Miscellany

Jai Ganesh · 2024-10-23 00:03:41

2251) Asphalt

Gist

Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac or bitumen macadam in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads, parking lots, airports, and the core of embankment dams.

Asphalt is known as a mixture of bitumen (as binding material) and a significant amount of inert minerals such as sand, gravel, and crushed stone. It has a blackish-brown colour and is available as a solid at low temperatures and as a liquid at temperatures above 50°C.

Summary

asphalt, black or brown petroleum-like material that has a consistency varying from viscous liquid to glassy solid. It is obtained either as a residue from the distillation of petroleum or from natural deposits. Asphalt consists of compounds of hydrogen and carbon with minor proportions of nitrogen, sulfur, and oxygen. Natural asphalt (also called brea), which is believed to be formed during an early stage in the breakdown of organic marine deposits into petroleum, characteristically contains minerals, while residual petroleum asphalt does not.

The use of asphalt is very old, dating back to its use as a water stop between brick walls of a reservoir at Mohenjo-Daro (about the 3rd millennium bc) in Pakistan. In the Middle East it was extensively used for paving roads and sealing waterworks, important applications even today. The Pitch Lake on the island of Trinidad was the first large commercial source, but natural sources have since declined in importance as petroleum became the major source. Gilsonite, wurzilite, and similar vein asphalts have special uses in heat-resistant enamels; they are hard and are mined like coal. Petroleum asphalt is produced in all consistencies from light road oils to heavy, high-viscosity industrial types.

Asphalt softens when heated and is elastic under certain conditions. The mechanical properties of asphalt are of little significance except when it is used as a binder or adhesive. The principal application of asphalt is in road surfacing, which may be done in a variety of ways. Light oil “dust layer” treatments may be built up by repetition to form a hard surface, or a granular aggregate may be added to an asphalt coat, or earth materials from the road surface itself may be mixed with the asphalt.

Other important applications include canal and reservoir linings, dam facings, and other harbour and sea works; asphalt so used may be a thin, sprayed membrane, covered with earth for protection against weathering and mechanical damage, or thicker surfaces, often including riprap (crushed rock). Asphalt is also used for roofs, coatings, floor tilings, soundproofing, waterproofing, and other building-construction elements and in a number of industrial products, such as batteries. For certain applications an asphaltic emulsion is prepared, in which fine globules of asphalt are suspended in water.

Details

Asphalt is a mixture of aggregates, binder and filler, used for constructing and maintaining roads, parking areas, railway tracks, ports, airport runways, bicycle lanes, sidewalks and also play- and sport areas.

Aggregates used for asphalt mixtures could be crushed rock, sand, gravel or slags. Nowadays, certain waste and by-products, such as construction and demolition debris, are being used as aggregates, which increases the sustainability of asphalt.

In order to bind the aggregates into a cohesive mixture a binder is used. Most commonly, bitumen is used as a binder, although nowadays, a series of bio-based binders are also under development with the aim of minimising the environmental impact of the roads.

An average asphalt pavement consists of the road structure above the formation level which includes unbound and bituminous-bound materials. This gives the pavement the ability to distribute the loads of the traffic before it arrives at the formation level.

How is asphalt produced?

Asphalt is produced in an asphalt plant. This can be a fixed plant or even in a mobile mixing plant. It is possible to produce in an asphalt plant up to 800 tons per hour. The average production temperature of hot mix asphalt is between 150 and 180°C, but nowadays new techniques are available to produce asphalt at lower temperatures.

Different kinds of asphalt

To be able to provide the best performance to different applications, a large variety of asphalt mixes can be used. Due to the different requirements (amount of traffic, amount of heavy vehicles, temperature, weather conditions, noise reduction requirements, etc.) the respective mix used needs to have an sufficient stiffness and resistance to deformation in order to cope with the applied pressure from vehicle wheels on the one hand, yet on the other hand, they need to have an adequate flexural strength to resist cracking caused by the varying pressures exerted on them. Moreover, good workability during application is essential in order to ensure that they can be fully compacted to achieve optimum durability.

Asphalt mixtures can be produced at different temperatures:

Hot Mix Asphalt (HMA)

Hot asphalt mixes are generally produced at a temperature between 150 and 180 °C. Depending on the usage, a different asphalt mixture can be used. For more details of the different asphalt mixtures, go to “Asphalt products”

Warm Mix Asphalt (WMA)

A typical WMA is produced at a temperature around 20 – 40 °C lower than an equivalent Hot Mix Asphalt. Significantly less energy is involved and, consequently, less fumes are produced (as rule of thumb, a reduction of 25ºC produces a reduction of 75% of fumes emission). In addition, during the paving operations, the temperature of the material is lower, resulting in improved working conditions for the crew and an earlier opening of the road.

Cold Mix Asphalt

Cold mixes are produced without heating the aggregate. This is only possible, due to the use of bitumen emulsified in water, which breaks either during compaction or during mixing. Producing the coating of the aggregate. Over the curing time, water evaporates and strength increases. Cold mixes are particularly recommendable for lightly trafficked roads.

Different asphalt layers

An asphalt pavement consists of different asphalt layers.

In general the asphalt layers are paved on a bound or unbound road base layer. Starting at the road surface, the first layer is called the surface course. The second layer is mostly called the binder course. The lower layers are the base courses.

Surface course

The surface course constitutes the top layer of the pavement and should be able to withstand high traffic- and environmentally-induced stresses without exhibiting unsatisfactory cracking and rutting. Its main mission is to provide an even profile for the comfort of the user, while providing enough texture to ensure minimum and safe skid resistance. Depending on local conditions, functional characteristics such as skid resistance, noise reduction and durability are often required for wearing courses. In some cases, rapid drainage of surface water is desired while in other cases, the wearing course should be impermeable in order to keep water out of the pavement structure. A wide range of surface layer products can be used depending on specific requirements.

Binder course

Binder courses are designed to withstand the highest shear stresses that occur about 50 – 70 mm below the asphalt surface. The binder course is therefore placed between the surface course and base course to reduce rutting by combining qualities of stability and durability. Stability can be achieved by sufficient stone-on-stone contact and stiff and/or modified binders.

Base course

The base course is perhaps the most important structural layer of the pavement, which is intended to effectively distribute traffic and environmental loading in such a way that underlying unbound layers are not exposed to excessive stresses and strains. This often implies comparatively high stiffness of the base course. Next to this the base course should also show adequate fatigue resistance.

Unbound materials and foundation

Since the formation and sub-soil often constitute relatively weak materials, it is of utmost importance that the damaging loadings are effectively eliminated by the layers above. In this case, unbound road-base or sub-base layers consisting of uncrushed or crushed aggregate can be suitable.

Additional Information

Asphalt is a dark brown to black, highly viscous, hydrocarbon produced from petroleum distillation residue. This distillation can occur naturally, resulting in asphalt lakes, or occur in a petroleum refinery using crude oil. In 2020, the U.S. produced about 21 million tons of asphalt (US EIA). Roads and highways constitute the largest single use of asphalt at about 80 percent of the total (Fredonia Group). In HMA, asphalt functions as a waterproof, thermoplastic, viscoelastic adhesive. By weight, asphalt generally accounts for between 4 and 8 percent of HMA and makes up about 25 – 30 percent of the cost of an HMA pavement structure depending upon the type and quantity. The paving industry also uses asphalt emulsions, asphalt cutbacks and foamed asphalt.

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Jai Ganesh · 2024-10-24 00:02:59

2252) Millenium

Gist

A millennium is a period of one thousand years, especially one which begins and ends with a year ending in `000,' for example the period from the year 1000 to the year 2000. [formal]

Since in Latin mille means "thousand", a millennium lasts 1,000 years.

A millennium ( pl. millennia or millenniums) is a period of one thousand years or one hundred decades or ten centuries, sometimes called a kiloannum (ka), or kiloyear (ky).

Summary

A millennium is a period of 1,000 years. The Gregorian calendar, put forth in 1582 and subsequently adopted by most countries, did not include a year 0 in the transition from bc (years before Christ) to ad (those since his birth). Thus, the 1st millennium is defined as spanning years 1–1000 and the 2nd the years 1001–2000.

A millennium is a period of 1,000 years. The Gregorian calendar, put forth in 1582 and subsequently adopted by most countries, did not include a year 0 in the transition from bc (years before Christ) to ad (those since his birth). Thus, the 1st millennium is defined as spanning years 1–1000 and the 2nd the years 1001–2000. Although numerous popular celebrations marked the start of the year 2000, the 21st century and 3rd millennium ad began on January 1, 2001.

Details

A millennium (pl. millennia or millenniums) is a period of one thousand years or one hundred decades or ten centuries, sometimes called a kiloannum (ka), or kiloyear (ky). Normally, the word is used specifically for periods of a thousand years that begin at the starting point (initial reference point) of the calendar in consideration and at later years that are whole number multiples of a thousand years after the start point.[clarification needed] The term can also refer to an interval of time beginning on any date. Millennia sometimes have religious or theological implications.

The word millennium derives from the Latin mille, thousand, and annus, year.

There was a public debate leading up to the celebrations of the year 2000 as to whether the beginning of that year should be understood as the beginning of the "new" millennium. Historically, there has been debate around the turn of previous decades, centuries, and millennia, but not so much for decades. The issue arises from the difference between the convention of using ordinal numbers to count years and millennia, as in "the third millennium", or using a vernacular description, as in "the two thousands". The difference of opinion comes down to whether to celebrate, respectively, the end or the beginning of the "-000" year. The first convention is common in English-speaking countries, but the latter is favoured in, for example, Sweden (tvåtusentalet, which translates literally as the two thousands period).

Those holding that the arrival of the new millennium should be celebrated in the transition from 2000 to 2001 (i.e., December 31, 2000, to January 1, 2001) argued that the Anno Domini system of counting years began with the year 1 (there was no year 0) and therefore the first millennium was from the year 1 to the end of the year 1000, the second millennium from 1001 to the end of 2000, and the third millennium beginning with 2001 and ending at the end of 3000. Similarly, the first millennium BC was from the year 1000 BC to the end of the year 1 BC.

Popular culture supported celebrating the arrival of the new millennium in the transition from 1999 to 2000 (i.e., December 31, 1999, to January 1, 2000), in that the change of the hundreds digit in the year number, with the zeroes rolling over, is consistent with the vernacular demarcation of decades by their 'tens' digit (e.g. naming the period 1980 to 1989 as "the 1980s" or "the eighties"). This has been described as "the odometer effect". Also, the "year 2000" had been a popular phrase referring to an often utopian future, or a year when stories in such a future were set. There was also media and public interest in the Y2K computer bug.

A third position was expressed by Bill Paupe, honorary consul for Kiribati: "To me, I just don't see what all the hoopla is about ... it's not going to change anything. The next day the sun is going to come up again and then it will all be forgotten." Even for those who did celebrate, in astronomical terms, there was nothing special about this particular event.

Stephen Jay Gould, in his essay "Dousing Diminutive Dennis' Debate (or DDDD = 2000)", discussed the "high" versus "pop" culture interpretation of the transition. Gould noted that the high culture, strict construction had been the dominant viewpoint at the 20th century's beginning, but that the pop culture viewpoint dominated at its end.

The start of the 21st century and 3rd millennium was celebrated worldwide at the start of the year 2000. One year later, at the start of the year 2001, the celebrations had largely returned to the usual ringing in of just another new year, although some welcomed "the real millennium", including America's official timekeeper, the U.S. Naval Observatory, and the countries of Cuba and Japan.

The popular approach was to treat the end of 1999 as the end of "a millennium" and to hold millennium celebrations at midnight between December 31, 1999, and January 1, 2000, with the cultural and psychological significance of the events listed above combining to cause celebrations to be observed one year earlier than the formal date.

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Jai Ganesh · 2024-10-25 00:23:45

2253) Liquid Paraffin

Gist

Liquid paraffin is primarily used as a pediatric laxative in medicine and is a popular treatment for constipation and encopresis. Because of its ease of titration, the drug is convenient to synthesize.

Liquid Parafin belongs to the group of medicines called 'laxatives' used to treat constipation in conditions like piles, fistula, fissures, pre/post-operative conditions, elderly and bed-ridden patients. Constipation refers to infrequent bowel movements in which the stools are often dry, painful, and hard to pass.

Summary

Liquid paraffin is a mixture of liquid hydrocarbons. Its main use has been as a lubricant laxative but it is not recommended, because of its adverse effects. Nevertheless, it continues to be used for this purpose and is reportedly as effective as lactulose . However, the erstwhile Committee on Safety of Medicines in the UK recommended the following precautions :

• pack sizes to be limited to 160 ml;
• liquid paraffin to be used only for the symptomatic relief of constipation;
• prolonged use to be avoided and the package label to state “repeated use is not recommended”;
• to be contraindicated in children under 3 years of age.

Liquid paraffin has also been used in ointments, as an emollient in skin diseases, and as a lubricant in treating dry eyes. Injection of liquid paraffin into the pleural cavity (oleothorax) was a widely used treatment for pulmonary tuberculosis before effective antituberculosis drugs became available. Long-term complications continue to be reported.

Details

Liquid paraffin, also known as paraffinum liquidum, paraffin oil, liquid paraffin oil or Russian mineral oil, is a very highly refined mineral oil used in cosmetics and medicine. Cosmetic or medicinal liquid paraffin should not be confused with the paraffin (i.e. kerosene) used as a fuel. The generic sense of paraffin meaning alkane led to regional differences for the meanings of both paraffin and paraffin oil. It is a transparent, colorless, nearly odorless, and oily liquid that is composed of saturated hydrocarbons derived from petroleum.

The term paraffinum perliquidum is sometimes used to denote light liquid paraffin, while the term paraffinum subliquidum is sometimes used to denote a thicker mineral oil.

History

Petroleum is said to have been used as a medicine since 400 BC, and has been mentioned in the texts of classical writers Herodotus, Plutarch, Dioscorides, Pliny, and others. It was used extensively by early Arabians and was important in early Indian medicine. Its first use internally is attributed to Robert A. Chesebrough, who patented it in 1872 for the manufacture of a "new and useful product from petroleum." After Sir W. Arbuthnot Lane, who was then Chief Surgeon of Guy's Hospital, recommended it as a treatment for intestinal stasis and chronic constipation in 1913, liquid paraffin gained more popularity.

Usage in medicine

Liquid paraffin is primarily used as a pediatric laxative in medicine and is a popular treatment for constipation and encopresis. Because of its ease of titration, the drug is convenient to synthesize. It acts primarily as a stool lubricant, and is thus not associated with abdominal cramps, diarrhea, flatulence, disturbances in electrolytes, or tolerance over long periods of usage, side effects that osmotic and stimulant laxatives often engender (however, some literature suggests that these may still occur). The drug acts by softening the feces and coats the intestine with an oily film. Because of this it reduces the pain caused by certain conditions such as piles (haemorrhoids). These traits make the drug ideal for chronic childhood constipation and encopresis, when large doses or long-term usage is necessary.

Consensus has not been entirely reached on the safety of the drug for children. While the drug is widely accepted for the management of childhood constipation in North America and Australia, the drug is used much less in the United Kingdom. The drug is endorsed by the American Academy of Pediatrics and the North American Society for Gastroenterology and Nutrition, with the latter organization outlining it as a first choice for the management of pediatric constipation. The drug is suggested to never be used in cases in which the patient is neurologically impaired or has a potential swallowing dysfunction due to potential respiration complications. Lipoid pneumonia due to mineral oil aspiration is thus a recognized severe complication of this medication, and there is a need for a heightened awareness among caregivers about the potential dangers of inappropriate mineral oil use. Some go as far as saying that it should never be used with children due to this risk.

Liquid paraffin is also used in combination with magnesium as an osmotic laxative, sold under the trade name Mil-Par (among others).

Additionally, it may be used as a release agent, binder, or lubricant on capsules and tablets.

Usage in cosmetics

Liquid paraffin is a hydrating and cleansing agent. Hence, it is used in several cosmetics both for skin and hair products. It is also used as one of the ingredients of after wax wipes.

Health

Upon being taken orally, liquid paraffin might interfere with the absorption of fat-soluble vitamins, though evidence does not seem to fully support this. It can be absorbed into the intestinal wall and may cause foreign-body granulomatous reactions in some rat species. These reactions might not occur in humans, however. Some evidence suggests that it engenders a lack of carcinogenicity. If liquid paraffin enters the lungs, it can cause lipoid pneumonia.

If injected, it can cause granulomatous reactions.

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Jai Ganesh · 2024-10-26 00:02:23

2254) Anthracite

Gist

The principal use of anthracite today is for a domestic fuel in either hand-fired stoves or automatic stoker furnaces. It delivers high energy per its weight and burns cleanly with little soot, making it ideal for this purpose. Its high value makes it prohibitively expensive for power plant use.

Summary

Anthracite is the most highly metamorphosed form of coal. It contains more fixed carbon (86 percent or greater on a dry, ash-free basis) than any other form of coal and the least amount of volatile matter (14 percent or less on a dry, ash-free basis), and it has calorific values near 35 megajoules per kilogram (approximately 15,000 British thermal units per pound), not much different from the calorific values for most bituminous coal. Anthracite is the least plentiful form of coal. In the United States it is found mostly in northeastern Pennsylvania and makes up less than 2 percent of all coal reserves in the country. Smaller amounts of anthracite occur in South Africa, Australia, eastern Ukraine, western Canada, China, and other countries.

Anthracites are black to steel gray and have a brilliant, almost metallic lustre. They can be polished and used for decorative purposes. Hard and brittle, anthracites break with conchoidal fracture into sharp fragments. Unlike many bituminous coals, they are clean to the touch. Although anthracites are difficult to ignite, they burn with a pale blue flame and require little attention to sustain combustion. In the past they were used for domestic heating because they produce little dust upon handling, burn slowly, and emit relatively little smoke. Anthracite is rarely used for this purpose today because of its limited abundance and relatively high cost and the ready availability of other sources of energy (e.g., natural gas and electricity) for heating purposes.

Although anthracites usually occur in geologically deformed areas, such as in the intensely folded sedimentary rocks of the anthracite region of Pennsylvania, their origin is due to higher than normal heating caused by the presence of nearby igneous intrusions or high geothermal gradients. Both of these phenomena produce temperatures much higher than those reached at depth in most sedimentary basins. For instance, in Antarctica, large igneous sills intruded the coal measures and converted some of the existing bituminous coal to anthracite. Temperatures ranging from 170 to 250 °C (about 340 to 480 °F) are thought to be necessary for the formation of anthracite.

Details

Anthracite, also known as hard coal and black coal, is a hard, compact variety of coal that has a submetallic lustre. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.

The Coal Region of Northeastern Pennsylvania in the United States has the largest known deposits of anthracite coal in the world with an estimated reserve of seven billion short tons. China accounts for the majority of global production; other producers include Russia, Ukraine, North Korea, South Africa, Vietnam, Australia, Canada, and the United States. Total production in 2020 was 615 million tons.

Anthracite is the most metamorphosed type of coal, but still represents low-grade metamorphism, in which the carbon content is between 86% and 97%. The term is applied to those varieties of coal which do not give off tarry or other hydrocarbon vapours when heated below their point of ignition. Anthracite is difficult to ignite, and burns with a short, blue, and smokeless flame.

Anthracite is categorized into several grades. Standard grade is used predominantly in power generation, and high grade (HG) and ultra high grade (UHG), are used predominantly in the metallurgy sector. Anthracite accounts for about 1% of global coal reserves, and is mined in only a few countries around the world.

Names

Anthracite derives from the Greek anthrakítēs, literally "coal-like". Other terms which refer to anthracite are black coal, hard coal, stone coal, dark coal, coffee coal, blind coal (in Scotland), Kilkenny coal (in Ireland), crow coal or craw coal, and black diamond. "Blue Coal" is the term for a once-popular and trademarked brand of anthracite, mined by the Glen Alden Coal Company in Pennsylvania, and sprayed with a blue dye at the mine before shipping to its Northeastern U.S. markets to distinguish it from its competitors.

Culm has different meanings in British and American English. In British English, culm is the imperfect anthracite, located predominantly north Devon and Cornwall, which was used as a pigment. The term is also used to refer to some carboniferous rock strata found in both Britain and in the Rhenish hill countries, also known as the Culm Measures. In Britain, it may also refer to coal exported from Britain during the 19th century. In American English, "culm" refers to the waste or slack from anthracite mining, mostly dust and small pieces not suitable for use in home furnaces.

Properties

Anthracite is similar in appearance to the mineraloid jet and is sometimes used as a jet imitation.

Anthracite differs from ordinary bituminous coal by its greater hardness (2.75–3 on the Mohs scale), its higher relative density of 1.3–1.4, and luster, which is often semi-metallic with a mildly green reflection. It contains a high percentage of fixed carbon and a low percentage of volatile matter. It is also free from included soft or fibrous notches and does not soil the fingers when rubbed. Anthracitization is the transformation of bituminous coal into anthracite.

The moisture content of fresh-mined anthracite generally is less than 15 percent. The heat content of anthracite ranges from 26 to 33 MJ/kg (22 to 28 million Btu/short ton) on a moist, mineral-matter-free basis. The heat content of anthracite coal consumed in the United States averages 29 MJ/kg (25 million Btu/ton), on the as-received basis, containing both inherent moisture and mineral matter.

Since the 1980s, anthracite refuse or mine waste has been used for coal power generation in a form of recycling. The practice known as reclamation is being applied to culm piles antedating laws requiring mine owners to restore lands to their approximate original condition.

Chemically, anthracite may be considered as a transition stage between ordinary bituminous coal and graphite, produced by the more or less complete elimination of the volatile constituents of the former, and it is found most abundantly in areas that have been subjected to considerable stresses and pressures, such as the flanks of great mountain ranges. Anthracite is associated with strongly deformed sedimentary rocks that were subjected to higher pressures and temperatures (but short of metamorphic conditions) just as bituminous coal is generally associated with less deformed or flat-lying sedimentary rocks. The compressed layers of anthracite that are deep mined in the folded Ridge and Valley Province of the Appalachian Mountains of the Coal Region of East-central Pennsylvania are extensions of the same layers of bituminous coal that are mined on the generally flat lying and undeformed sedimentary rocks further west on the Allegheny Plateau of Kentucky and West Virginia, Eastern Ohio, and Western Pennsylvania.

In the same way the anthracite region of South Wales is confined to the contorted portion west of Swansea and Llanelli, the central and eastern portions producing steam coal, coking coal and domestic house coals.

Anthracite shows some alteration by the development of secondary divisional planes and fissures so that the original stratification lines are not always easily seen. The thermal conductivity is also higher; a lump of anthracite feels perceptibly colder when held in the warm hand than a similar lump of bituminous coal at the same temperature.

Anthracite has a history of use in blast furnaces for iron smelting; however, it lacked the pore space of metallurgical coke, which eventually replaced anthracite.

Additional Information

Hard and very brittle, anthracite is dense, shiny black, and homogeneous with no marks of layers. Unlike the lower rank coals, it has a high percentage of fixed carbon and a low percentage of volatile matter. Anthracites include a variety of slow-burning fuels merging into graphite at one end and bituminous coal at the other. They are the hardest coals on the market, consisting almost entirely of fixed carbon, with the little volatile matter present in them chiefly as methane, CH4. Anthracite is usually graded into small sizes before being burned on stokers: the ‘meta-anthracites’ burn so slowly as to require mixing with other coals, while the ‘semi-anthracites’, which have more volatile matter, are burned with relative ease if proper fired. Most anthracites have a lower heating value than the highest-grade bituminous coals. Anthracite is used principally for heating homes and in gas production.

Some semi-anthracites are dense, but softer than anthracite. This grade is shiny gray and somewhat granular in structure. The grains have a tendency to break off in handling and produce coarse, sand-like slack.

Other semi-anthracites are dark gray and distinctly granular. The grains break off easily in handling and produce a coarse slack. The granular structure has been produced by small vertical cracks in horizontal layers of comparatively pure coal separated by very thin partings. The cracks are the result of heavy downward pressure and shrinkage of the pure coal because of a drop in temperature.

Jai Ganesh · 2024-10-27 22:43:10

2255) Analgesic

Gist

Analgesics are medications used in the management and treatment of pain. They include several classes of medications (acetaminophen, nonsteroidal anti-inflammatory drugs, antidepressants, antiepileptics, local anesthetics, and opioids).

Analgesics are medications that relieve pain. They work either by reducing inflammation or by changing the way the brain processes and perceives pain. Side effects include heartburn, nausea, and headaches.

Some types of analgesics are available over the counter. However, stronger variants are available only with a prescription. This is because strong analgesics are more likely to cause side effects such as dependence, addiction, and withdrawal symptoms.

Summary

Analgesics are drugs that eliminate or alleviate the feeling of pain that accompanies many pathologic conditions. It is difficult to list all the situations in which it is necessary to use analgesics, for example, muscle aches and headaches, and where there is no possibility of becoming addicted. Analgesics are divided into two groups such as opioids, which predominantly influence the central nervous system (CNS), and Nonopioids, which act predominantly on the peripheral nervous system. Opioids are further subdivided into three large subgroups according to their action on opioids receptors such as agonists, mixed agonists/antagonists, and antagonists. Opioid agonists act first and foremost on μ-receptors. Reaction of agonists with opioid μ-receptors leads to an increase in the flow of potassium ions from the cell, simultaneously making it difficult for calcium ions to flow into the cell, which makes neurons less excitable. Opioid antagonists on the other hand also bind to opioid receptors but do not activate them. These compounds are not used for analgesia. Their therapeutic value is in relieving side effects that result from either absolute of relative overdoses or intolerance of drugs by patients, and also in treating cases of Opioid dependency. Drugs of mixed agonists/antagonists group display both agonistic and antagonistic activities. This group of compounds is used for analgesia in cases of moderate-to-severe pain. The chapter lists down widely used agnostic, antagonistic, and mixed agnostic/antagonistic drugs such as Morphine, Codeine, Heroin, Hydromorphone, Oxymorphone, Nalorphine, Pentazocine, Nalbuphine, Naloxone, and Naltrexone, highlighting their chemical structure, specific uses and synthesis. The chapter end with a discussion on non-steroid anti-inflammatory drugs and anti-fever analgesics, such as Salicylic acid derivatives, Pyrazolonees and p-Aminophenol derivatives.

Details

Analgesics are medications that relieve pain. They work either by reducing inflammation or by changing the way the brain processes and perceives pain. Side effects include heartburn, nausea, and headaches.

Some types of analgesics are available over the counter. However, stronger variants are available only with a prescription. This is because strong analgesics are more likely to cause side effects such as dependence, addiction, and withdrawal symptoms.

An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in some instances eliminate, sensation, although analgesia and anesthesia are neurophysiologically overlapping and thus various drugs have both analgesic and anesthetic effects.

Analgesic choice is also determined by the type of pain: For neuropathic pain, recent research has suggested that classes of drugs that are not normally considered analgesics, such as tricyclic antidepressants and anticonvulsants may be considered as an alternative.

Various analgesics, such as many NSAIDs, are available over the counter in most countries, whereas various others are prescription drugs owing to the substantial risks and high chances of overdose, misuse, and addiction in the absence of medical supervision.

Classification

Analgesics are typically classified based on their mechanism of action.

Paracetamol (acetaminophen)

Paracetamol, also known as acetaminophen or APAP, is a medication used to treat pain and fever. It is typically used for mild to moderate pain. In combination with opioid pain medication, paracetamol is now used for more severe pain such as cancer pain and after surgery. It is typically used either by mouth or rectally but is also available intravenously. Effects last between two and four hours. Paracetamol is classified as a mild analgesic. Paracetamol is generally safe at recommended doses.

NSAIDs

Nonsteroidal anti-inflammatory drug

Nonsteroidal anti-inflammatory drugs (usually abbreviated to NSAIDs), are a drug class that groups together drugs that decrease pain and lower fever, and, in higher doses, decrease inflammation. The most prominent members of this group of drugs, aspirin, ibuprofen and naproxen, Diclofenac are all available over the counter in most countries.

COX-2 inhibitors

These drugs have been derived from NSAIDs. The cyclooxygenase enzyme inhibited by NSAIDs was discovered to have at least two different versions: COX1 and COX2. Research suggested most of the adverse effects of NSAIDs to be mediated by blocking the COX1 (constitutive) enzyme, with the analgesic effects being mediated by the COX2 (inducible) enzyme. Thus, the COX2 inhibitors were developed to inhibit only the COX2 enzyme (traditional NSAIDs block both versions in general). These drugs (such as rofecoxib, celecoxib, and etoricoxib) are equally effective analgesics when compared with NSAIDs, but cause less gastrointestinal hemorrhage in particular.

After widespread adoption of the COX-2 inhibitors, it was discovered that most of the drugs in this class increase the risk of cardiovascular events by 40% on average. This led to the withdrawal of rofecoxib and valdecoxib, and warnings on others. Etoricoxib seems relatively safe, with the risk of thrombotic events similar to that of non-coxib NSAID diclofenac.

Additional Information

An analgesic, any drug that relieves pain selectively without blocking the conduction of nerve impulses, markedly altering sensory perception, or affecting consciousness. This selectivity is an important distinction between an analgesic and an anesthetic.

Analgesics may be classified into two types: anti-inflammatory drugs, which alleviate pain by reducing local inflammatory responses; and the opioids, which act on the brain. The opioid analgesics were once called narcotic drugs because they can induce sleep. The opioid analgesics can be used for either short-term or long-term relief of severe pain. In contrast, the anti-inflammatory compounds are used for short-term pain relief and for modest pain, such as that of headache, muscle strain, bruising, or arthritis.

Anti-inflammatory analgesics

Most anti-inflammatory analgesics are derived from three compounds discovered in the 19th century—salicylic acid, pyrazolone, and phenacetin (or acetophenetidin). Although chemically unrelated, the drugs in these families have the ability to relieve mild to moderate pain through actions that reduce inflammation at its source. Acetylsalicylic acid, or aspirin, which is derived from salicylic acid, is the most widely used mild analgesic. It is considered the prototype for anti-inflammatory analgesics, the two other major types of which include acetaminophen (a derivative of phenacetin) and the aspirin-like drugs, or nonsteroidal anti-inflammatory drugs (NSAIDs), which include compounds such as ibuprofen, naproxen, and fenoprofen. Pyrazolone derivatives, with some exceptions, are no longer widely used in many countries, because of their tendency to cause an acute infection known as agranulocytosis.

Aspirin and NSAIDs appear to share a similar molecular mechanism of action—namely, inhibition of the synthesis of prostaglandins (natural products of inflamed white blood cells) that induce the responses in local tissue that include pain and inflammation. In fact, aspirin and all aspirin-like analgesics, including indomethacin and sulindac, which are derived from a heterocyclic organic compound known as indole, inhibit prostaglandin synthesis and release. All these agents can be further divided into nonselective COX inhibitors and selective COX inhibitors. COX, or cyclooxygenase, is an enzyme responsible for the synthesis of prostaglandins and related compounds. It has two forms, COX-1, which is found in most normal tissues, and COX-2, which is induced in the presence of inflammation. Because COX-2 is not normally expressed in the stomach, the use of COX-2 inhibitors (e.g., rofecoxib, celecoxib) seems to result in less gastric ulceration than occurs with other anti-inflammatory analgesics, particularly aspirin. However, COX-2 inhibitors do not reduce the ability of platelets to form clots, a benefit associated with aspirin and other nonselective COX inhibitors.

Preferences in COX selectivity and the possibility of additional molecular actions of NSAIDs may explain differences in the therapeutic effects between aspirin, acetaminophen, and NSAIDs. For example, while aspirin is effective in reducing fever, as well as relieving inflammation, acetaminophen and NSAIDs are more potent antipyretic (fever-reducing) analgesics. Acetaminophen, on the other hand, possesses inferior anti-inflammatory activity compared with aspirin and NSAIDs and thus is relatively ineffective in treating inflammatory conditions such as rheumatoid arthritis. Despite this, acetaminophen is a popular mild analgesic and antipyretic and is a suitable alternative to aspirin for patients who develop severe symptoms of stomach irritation, because it is not as harmful to the gastrointestinal tract.

As might be expected from their common mechanisms of action, many of the anti-inflammatory analgesic drugs share similar side effects. Hypersensitivity responses to aspirin-like drugs are thought to be due to an accumulation of prostaglandins after the pathways that break down prostaglandins are blocked. These responses can be fatal when very strong anti-inflammatory compounds are given. Inhibition of prostaglandin synthesis may result in other serious side effects, such as peptic ulcers and a reduced ability of platelets in the blood to aggregate and form clots. The latter effect, however, has given aspirin an added use as a prophylactic antithrombotic drug to reduce chances of cardiac or cerebral vascular thrombosis—the formation of a clot in a blood vessel in the heart or brain. Some aspirin-like analgesics also have specific toxic effects: liver damage occasionally occurs after administration of acetaminophen, and renal toxicity is sometimes seen with use of NSAIDs. Aspirin itself, taken in overdose, can cause deafness, ringing in the ears, diarrhea, nausea, and headache, which disappear when the dose is reduced or stopped. Aspirin is also thought to be a causative agent of Reye syndrome, a rare and serious degenerative disease of the brain and fatty tissue of the liver that accompanies certain viral infections in children and young adults.

Jai Ganesh · 2024-10-30 00:03:20

2256) Pseudopodia

Gist

A pseudopod or pseudopodium ( pl. : pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments.

Summary

Pseudopodium, temporary or semipermanent extension of the cytoplasm, used in locomotion and feeding by all sarcodine protozoans (i.e., those with pseudopodia) and some flagellate protozoans. Pseudopodia are formed by some cells of higher animals (e.g., white blood corpuscles) and by amoebas. During amoeboid feeding, pseudopodia either flow around and engulf prey or trap it in a fine, sticky mesh.

Protozoans have four types of pseudopodia. Lobopodia, characteristic of Amoeba, are blunt and fingerlike; filopodia are slender and tapering, occasionally forming simple, branched networks; reticulopodia, found in the foraminiferans, are branching filaments that fuse to form food traps; and axopodia, characteristic of the actinopods, are long and sticky (like reticulopodia) but radiate singly and have a stiff, internal rod composed of numerous microtubules. Lobopodia and filopodia are formed as the result of a pressure system; reticulopodia and axopodia depend on a two-way flow of cytoplasm.

Details

A pseudopod or pseudopodium (pl.: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments. Pseudopods are used for motility and ingestion. They are often found in amoebas.

Different types of pseudopodia can be classified by their distinct appearances. Lamellipodia are broad and thin. Filopodia are slender, thread-like, and are supported largely by microfilaments. Lobopodia are bulbous and amoebic. Reticulopodia are complex structures bearing individual pseudopodia which form irregular nets. Axopodia are the phagocytosis type with long, thin pseudopods supported by complex microtubule arrays enveloped with cytoplasm; they respond rapidly to physical contact.

Generally, several pseudopodia arise from the surface of the body, (polypodial, for example, Amoeba proteus), or a single pseudopod may form on the surface of the body (monopodial, such as Entamoeba histolytica).

Formation

Cells which make pseudopods are generally referred to as amoeboids.

Via extracellular cue

To move towards a target, the cell uses chemotaxis. It senses extracellular signalling molecules, chemoattractants (e.g. cAMP for Dictyostelium cells), to extend pseudopodia at the membrane area facing the source of these molecules.

The chemoattractants bind to G protein-coupled receptors, which activate GTPases of the Rho family (e.g. Cdc42, Rac) via G proteins.

Rho GTPases are able to activate WASp which in turn activate Arp2/3 complex which serve as nucleation sites for actin polymerization. The actin polymers then push the membrane as they grow, forming the pseudopod. The pseudopodium can then adhere to a surface via its adhesion proteins (e.g. integrins), and then pull the cell's body forward via contraction of an actin-myosin complex in the pseudopod. This type of locomotion is called amoeboid movement.

Rho GTPases can also activate phosphatidylinositol 3-kinase (PI3K) which recruit PIP3 to the membrane at the leading edge and detach the PIP3-degrading enzyme PTEN from the same area of the membrane. PIP3 then activate GTPases back via GEF stimulation. This serves as a feedback loop to amplify and maintain the presence of local GTPase at the leading edge.

Otherwise, pseudopodia cannot grow on other sides of the membrane than the leading edge because myosin filaments prevent them to extend. These myosin filaments are induced by cyclic GMP in D. discoideum or Rho kinase in neutrophils for example.

Different physical parameters were shown to regulate the length and time-scale of pseudopodia formation. For example, an increase in membrane tension inhibits actin assembly and protrusion formation. It was demonstrated that the lowered negative surface charge on the inner surface of the plasma membrane generates protrusions via activation of the Ras-PI3K/AKT/mTOR signalling pathway.

Without extracellular cue

In the case there is no extracellular cue, all moving cells navigate in random directions, but they can keep the same direction for some time before turning. This feature allows cells to explore large areas for colonization or searching for a new extracellular cue.

In Dictyostelium cells, a pseudopodium can form either de novo as normal, or from an existing pseudopod, forming a Y-shaped pseudopodium.

The Y-shaped pseudopods are used by Dictyostelium to advance relatively straight forward by alternating between retraction of the left or right branch of the pseudopod. The de novo pseudopodia form at different sides than pre-existing ones, they are used by the cells to turn.

Y-shaped pseudopods are more frequent than de novo ones, which explain the preference of the cell to keep moving to the same direction. This persistence is modulated by PLA2 and cGMP signalling pathways.

Functions

The functions of pseudopodia include locomotion and ingestion:

* Pseudopodia are critical in sensing targets which can then be engulfed; the engulfing pseudopodia are called phagocytosis pseudopodia. A common example of this type of amoeboid cell is the macrophage.
* They are also essential to amoeboid-like locomotion. Human mesenchymal stem cells are a good example of this function: these migratory cells are responsible for in-utero remodeling; for example, in the formation of the trilaminar germ disc during gastrulation.

Additional Information

A pseudopodium or pseudopod (plural: pseudopodia or pseudopods) is a temporary cytoplasmic extension of an amoeboid cell, used for locomotion and ingestion of food. The name means literally ‘false foot’. Pseudopodia are powered by microfilaments near the cellular membrane. About half of the internal space of an amoeba contains microfilaments. A pseudopodium contains both granuloplasm and hyaloplasm. Pseudopodia which only contain hyaloplasm are called subpseudopodia.

Jai Ganesh · 2024-10-31 22:26:27

2257) Nosebleed

Gist

Epistaxis, or a nosebleed, is when you lose blood from the tissue that lines the inside of your nose. A combination of dry air and tiny blood vessels that line the inner surface of your nose often cause nosebleeds.

Summary

A nosebleed is loss of blood from the tissue lining the nose. Bleeding most often occurs from one nostril only.

Considerations

Nosebleeds are very common. Most nosebleeds occur because of minor irritations of the inside of the nostrils or colds.

The nose contains many small blood vessels that bleed easily. Air moving through the nose can dry and irritate the membranes lining the inside of the nose. Crusts can form that bleed when irritated. Nosebleeds occur more often in the winter, when cold viruses are common and indoor air tends to be drier.

Most nosebleeds occur on the front of the nasal septum. This is the piece of the tissue that separates the two sides of the nose. This type of nosebleed can be easy for a trained professional to stop. Less commonly, nosebleeds may occur higher on the septum or deeper in the nose such as in the sinuses or the base of the skull. Such nosebleeds may be harder to control. However, nosebleeds are rarely life threatening.

Causes

Nosebleed can be caused by:

* Irritation due to allergies, colds, sneezing or sinus problems
* Very cold or dry air
* Blowing the nose very hard, or picking the nose
* Injury to nose, including a broken nose, or an object stuck in the nose
* Sinus or pituitary surgery (transsphenoidal)
* Deviated septum (tissue that divides the nose into 2 nostrils)
* Chemical irritants including medicines or drugs that are sprayed or snorted
* Overuse of decongestant nasal sprays
* Oxygen treatment through nasal cannulas
* Snorting cocaine or amphetamine

Repeated nosebleeds may be a symptom of another disease such as high blood pressure, a bleeding disorder, or a tumor of the nose or sinuses. Blood thinners, such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin, may cause or worsen nosebleeds.

Details

A nosebleed, also known as epistaxis, is an instance of bleeding from the nose. Blood can flow down into the stomach, and cause nausea and vomiting. In more severe cases, blood may come out of both nostrils. Rarely, bleeding may be so significant that low blood pressure occurs. Blood may also be forced to flow up and through the nasolacrimal duct and out of the eye, producing bloody tears.

Risk factors include trauma, including putting the finger in the nose, blood thinners, high blood pressure, alcoholism, seasonal allergies, dry weather, and inhaled corticosteroids. There are two types: anterior, which is more common; and posterior, which is less common but more serious. Anterior nosebleeds generally occur from Kiesselbach's plexus while posterior bleeds generally occur from the sphenopalatine artery or Woodruff's plexus. The diagnosis is by direct observation.

Prevention may include the use of petroleum jelly in the nose. Initially, treatment is generally the application of pressure for at least five minutes over the lower half of the nose. If this is not sufficient, nasal packing may be used. Tranexamic acid may also be helpful. If bleeding episodes continue, endoscopy is recommended.

About 60% of people have a nosebleed at some point in their life. About 10% of nosebleeds are serious. Nosebleeds are rarely fatal, accounting for only 4 of the 2.4 million deaths in the U.S. in 1999. Nosebleeds most commonly affect those younger than 10 and older than 50.

Cause

Nosebleeds can occur due to a variety of reasons. Some of the most common causes include trauma from nose picking, blunt trauma (such as a motor vehicle accident), or insertion of a foreign object (more likely in children). Low relative humidity (such as in centrally heated buildings), respiratory tract infections, chronic sinusitis, rhinitis or environmental irritants can cause inflammation and thinning of the tissue in the nose, leading to a greater likelihood of bleeding from the nose.

Most causes of nose bleeding are self-limiting and do not require medical attention. However, if nosebleeds are recurrent or do not respond to home therapies, an underlying cause may need to be investigated.

Pathophysiology

The nasal mucosa contains a rich blood supply that can be easily ruptured and cause bleeding. Rupture may be spontaneous or initiated by trauma. Nosebleeds are reported in up to 60% of the population with peak incidences in those under the age of ten and over the age of 50 and appear to occur in males more than females. An increase in blood pressure (e.g. due to general hypertension) tends to increase the duration of spontaneous epistaxis. Anticoagulant medication and disorders of blood clotting can promote and prolong bleeding. Spontaneous epistaxis is more common in the elderly as the nasal mucosa (lining) becomes dry and thin and blood pressure tends to be higher. The elderly are also more prone to prolonged nosebleeds as their blood vessels are less able to constrict and control the bleeding.

The vast majority of nosebleeds occur in the front anterior (front) part of the nose from the nasal septum. This area is richly endowed with blood vessels (Kiesselbach's plexus). This region is also known as Little's area. Bleeding farther back in the nose is known as a posterior bleed and is usually due to bleeding from Woodruff's plexus, a venous plexus situated in the posterior part of inferior meatus. Posterior bleeds are often prolonged and difficult to control. They can be associated with bleeding from both nostrils and with a greater flow of blood into the mouth.

Sometimes blood flowing from other sources of bleeding passes through the nasal cavity and exits the nostrils. It is thus blood coming from the nose but is not a true nosebleed, that is, not truly originating from the nasal cavity. Such bleeding is called "pseudoepistaxis" (pseudo + epistaxis). Examples include blood coughed up through the airway and ending up in the nasal cavity, then dripping out.

Prevention

People with uncomplicated nosebleeds can use conservative methods to prevent future nosebleeds such as sleeping in a humidified environment or applying petroleum jelly to the nasal nares.

Individuals who suffer from nosebleeds regularly, especially children, are encouraged to use over-the-counter nasal saline sprays and avoid vigorous nose-blowing as preventative measures.

Treatment

Most anterior nosebleeds can be stopped by applying direct pressure, which helps by promoting blood clots. Those who have a nosebleed should first attempt to blow out any blood clots and then apply pressure to the soft anterior part of the nose (by pinching the nasal ala; not the bony nasal bridge) for at least five minutes and up to 30 minutes. Pressure should be firm and tilting the head forward helps decrease the chance of nausea and airway obstruction due to blood dripping into the airway. When attempting to stop a nosebleed at home, the head should not be tilted back. Swallowing excess blood can irritate the stomach and cause vomiting. Vasoconstrictive medications such as oxymetazoline (Afrin) or phenylephrine are widely available over the counter for treatment of allergic rhinitis and may also be used to control benign cases of epistaxis. For example, a few sprays of oxymetazoline may be applied into the bleeding side(s) of the nose followed by application of direct pressure. Those with nosebleeds that last longer than 30 minutes (despite use of direct pressure and vasoconstrictive medications such as oxymetazoline) should seek medical attention.

Additional Information

Nosebleed is an attack of bleeding from the nose. It is a common and usually unimportant disorder but may also result from local conditions of inflammation, small ulcers or polypoid growths, or severe injuries to the skull. Vascular disease, such as high blood pressure, may provoke it, and such diseases as scurvy and hemophilia also may be responsible. Usually it is easily controlled by rest and application of cold and pressure. On occasion it may require expert care.

Jai Ganesh · 2024-11-02 00:04:12

2258) Baker

Gist

A bakery is an establishment that produces and sells flour-based baked goods made in an oven such as bread, cookies, cakes, doughnuts, bagels, pastries, and pies. Some retail bakeries are also categorized as cafés, serving coffee and tea to customers who wish to consume the baked goods on the premises.

Details

A bakery is an establishment that produces and sells flour-based baked goods made in an oven such as bread, cookies, cakes, doughnuts, bagels, pastries, and pies. Some retail bakeries are also categorized as cafés, serving coffee and tea to customers who wish to consume the baked goods on the premises. In some countries, a distinction is made between bakeries, which primarily sell breads, and pâtisseries, which primarily sell sweet baked goods.

History

Baked goods have been around for thousands of years. The art of baking was very popular during the Roman Empire. It was highly famous art as Roman citizens loved baked goods and demanded them frequently for important occasions such as feasts and weddings. Because of the fame of the art of baking, around 300 BC, baking was introduced as an occupation and respectable profession for Romans. Bakers began to prepare bread at home in an oven, using grist mills to grind grain into flour for their breads. The demand for baked goods persisted, and the first bakers' guild was established in 168 BC in Rome. The desire for baked goods promoted baking throughout Europe and expanded into eastern parts of Asia. Bakers started baking bread and other goods at home and selling them on the streets.

This trend became common, and soon, baked products were sold in streets of Rome, Germany, London, and more. A system of delivering baked goods to households arose as the demand increased significantly. This prompted bakers to establish places where people could purchase baked goods. The first open-air market for baked goods was established in Paris, and since then bakeries have become a common place to purchase delicious goods and to socialize.

On July 7, 1928, a bakery in Chillicothe, Missouri introduced sliced bread using the automatic bread-slicing machine, invented by Otto Frederick Rohwedder. While the bread initially failed to sell, due to its "sloppy" aesthetic, and the fact it went stale faster, it later became popular. In World War II bread slicing machines were effectively banned, as the metal in them was required for wartime use. When they were requisitioned, creating 100 tons of metal alloy, the decision proved very unpopular with housewives.

World War II directly affected the bread industry in the UK. Baking schools closed during this time, so when the war ended there was a lack of skilled bakers. This resulted in new methods being developed to satisfy the world's desire for bread, including chemical additives, premixes and specialised machinery. Old methods of baking were almost completely eradicated when these new methods were introduced and the industry became industrialised. The old methods were seen as unnecessary and financially unsound. During this period there were not many traditional bakeries left.

Specialities

Some bakeries provide services for special occasions (such as weddings, anniversaries, birthday parties, business networking events, etc.) or customized baked products for people who have allergies or sensitivities to certain foods (such as nuts, peanuts, dairy or gluten, etc.). Bakeries can provide a wide range of cake designs such as sheet cakes, layer cakes, wedding cakes, tiered cakes, etc. Other bakeries may specialize in traditional or hand-made types of baked products made with locally milled flour, without flour bleaching agents or flour treatment agents, baking what is sometimes referred to as artisan bread.

Commercialization

In many countries, many grocery stores and supermarkets sell "sliced bread" (prepackaged/presliced bread), cakes, and other pastries. They may also offer in-store baking, with products either fully baked on site or part-baked prior to delivery to store, and some offer cake decoration. Nonetheless, many people still prefer to get their baked goods from a small artisanal bakery, either out of tradition, the availability of a greater variety of baked products, or due to the higher quality products characteristic of the trade of baking.

Additional Information

Baking is the process of cooking by dry heat, especially in some kind of oven. It is probably the oldest cooking method. Bakery products, which include bread, rolls, cookies, pies, pastries, and muffins, are usually prepared from flour or meal derived from some form of grain. Bread, already a common staple in prehistoric times, provides many nutrients in the human diet.

History

The earliest processing of cereal grains probably involved parching or dry roasting of collected grain seeds. Flavour, texture, and digestibility were later improved by cooking whole or broken grains with water, forming gruel or porridge. It was a short step to the baking of a layer of viscous gruel on a hot stone, producing primitive flat bread. More sophisticated versions of flat bread include the Mexican tortilla, made of processed corn, and the chapati of India, usually made of wheat.

Baking techniques improved with the development of an enclosed baking utensil and then of ovens, making possible thicker baked cakes or loaves. The phenomenon of fermentation, with the resultant lightening of the loaf structure and development of appealing flavours, was probably first observed when doughs or gruels, held for several hours before baking, exhibited spoilage caused by yeasts. Some of the effects of the microbiologically induced changes were regarded as desirable, and a gradual acquisition of control over the process led to traditional methods for making leavened bread loaves. Early baked products were made of mixed seeds with a predominance of barley, but wheat flour, because of its superior response to fermentation, eventually became the preferred cereal among the various cultural groups sufficiently advanced in culinary techniques to make leavened bread.

Brewing and baking were closely connected in early civilizations. Fermentation of a thick gruel resulted in a dough suitable for baking; a thinner mash produced a kind of beer. Both techniques required knowledge of the “mysteries” of fermentation and a supply of grain. Increasing knowledge and experience taught the artisans in the baking and brewing trades that barley was best suited to brewing, while wheat was best for baking.

By 2600 bce the Egyptians, credited with the first intentional use of leavening, were making bread by methods similar in principle to those of today. They maintained stocks of sour dough, a crude culture of desirable fermentation organisms, and used portions of this material to inoculate fresh doughs. With doughs made by mixing flour, water, salt, and leaven, the Egyptian baking industry eventually developed more than 50 varieties of bread, varying the shape and using such flavouring materials as poppy seed, sesame, and camphor. Samples found in tombs are flatter and coarser than modern bread.

The Egyptians developed the first ovens. The earliest known examples are cylindrical vessels made of baked Nile clay, tapered at the top to give a cone shape and divided inside by a horizontal shelflike partition. The lower section is the firebox, the upper section is the baking chamber. The pieces of dough were placed in the baking chamber through a hole provided in the top.

In the first two or three centuries after the founding of Rome, baking remained a domestic skill with few changes in equipment or processing methods. According to Pliny the Elder, there were no bakers in Rome until the middle of the 2nd century bce. As well-to-do families increased, women wishing to avoid frequent and tedious bread making began to patronize professional bakers, usually freed slaves. Loaves molded by hand into a spheroidal shape, generally weighing about a pound, were baked in a beehive-shaped oven fired by wood. Panis artopticius was a variety cooked on a spit, panis testuatis in an earthen vessel.

Although Roman professional bakers introduced technological improvements, many were of minor importance, and some were essentially reintroductions of earlier developments. The first mechanical dough mixer, attributed to Marcus Vergilius (sometimes spelled Virgilius) Eurysaces, a freed slave of Greek origin, consisted of a large stone basin in which wooden paddles, powered by a horse or donkey walking in circles, kneaded the dough mixture of flour, leaven, and water.

Guilds formed by the miller-bakers of Rome became institutionalized. During the 2nd century ce, under the Flavians, they were organized into a “college” with work rules and regulations prescribed by government officials. The trade eventually became obligatory and hereditary, and the baker became a kind of civil servant with limited freedom of action.

During the early Middle Ages, baking technology advances of preceding centuries disappeared, and bakers reverted to mechanical devices used by the ancient Egyptians and to more backward practices. But in the later Middle Ages the institution of guilds was revived and expanded. Several years of apprenticeship were necessary before an applicant was admitted to the guild; often an intermediate status as journeyman intervened between apprenticeship and full membership (master). The rise of the bakers’ guilds reflected significant advances in technique. A 13th-century French writer named 20 varieties of bread varying in shape, flavourings, preparation method, and quality of the meal used. Guild regulations strictly governed size and quality. But outside the cities bread was usually baked in the home. In medieval England rye was the main ingredient of bread consumed by the poor; it was frequently diluted with meal made from other cereals or leguminous seeds. Not until about 1865 did the cost of white bread in England drop below brown bread.

At that time improvements in baking technology began to accelerate rapidly, owing to the higher level of technology generally. Ingredients of greater purity and improved functional qualities were developed, along with equipment reducing the need for individual skill and eliminating hand manipulation of bread doughs. Automation of mixing, transferring, shaping, fermentation, and baking processes began to replace batch processing with continuous operations. The enrichment of bread and other bakery foods with vitamins and minerals was a major accomplishment of the mid-20th-century baking industry.

Market preparation:

Slicing

Bread often is marketed in sliced form. Slicing is performed by parallel arrays of saw blades through which the loaves are carried by gravity or by conveyors. The blades may be endless bands carried on rotating drums, or relatively short strips held in a reciprocating frame. Most bread is sliced while still fairly warm, and the difficulty of cutting the sticky, soft crumb has led to development of coated blades and blade-cleaning devices. Horizontal slicing of hamburger rolls and similar products is accomplished by circular (disk) blades, usually two blades in a slicer, between which a connected array of four or six rolls is carried by a belt. The cutter blades are separated to avoid cutting completely through the roll, in order to leave a “hinge.”

Freezing

Freezing is an indispensable bakery industry process. Ordinary bread and rolls are rarely distributed and sold in frozen form because of the excessive cost in relation to product value, but a substantial percentage of all specialty products is sold in frozen form. Most bakery products respond well to freezing, although some cream fillings must be specially formulated to avoid syneresis, or gel breakdown. Rapid chilling in blast freezers is preferred, although milder methods may be used. Storage at −18 °C (0 °F) or lower is essential for quality maintenance. Thawing and refreezing is harmful to quality. Frozen bakery products can dehydrate under freezer conditions and must be packaged in containers resistant to moisture-vapour transfer.

Wrapping

Most American consumers prefer wrapped bread, and the trend toward wrapping is growing in other countries. Sanitary and aesthetic considerations dictate protection of the product from environmental contamination during distribution and display. Waxed paper was originally the only film used to package bread, after which cellophane became popular, and then polyethylene, polypropylene, and combination laminates became common. Other bakery products are packaged in a variety of containers ranging from open bags of greaseproof material to plastic trays with sealed foil overwraps.

Canning

The market for bakery products in tin cans is small, but hunters and campers find canned foods convenient. Canning protects against drying and environmental contamination, but texture staling and some degree of flavour staling still occur. In processing, an amount of dough or batter known to fill exactly the available space after baking is placed in a can, and the cover is loosely fastened to allow gases to escape. The product is then baked in a conventional oven, the lid is hermetically sealed immediately after baking, and the sealed can is sprayed with water to cool it. Vacuum sealing, needed to assure storage stability, can be routinely achieved by this method. Special can linings and sealing compounds are needed to survive oven temperatures, and the exterior should be dark-coloured (e.g., olive drab) in order to absorb radiant heat in the oven, avoiding long baking times. Spores of some pathogens are not killed by the conditions reached in the centre of the baked product, but pH and osmotic pressure can be adjusted to prevent growth of spoilage organisms. There is no record of food poisoning attributable to canned bakery food.

Jai Ganesh · 2024-11-03 00:01:45

2259) Administrator

Gist

An administrator is someone whose job is to manage a business or business activity.

The boss, the head honcho, the person in charge: An administrator is the person responsible for managing things and running the show.

Administrators are often found directing government agencies, organizing institutions, or leading school departments. They're the decision makers and the planners, the people who put in place or administer the rules and guidelines.

Administrators play a critical role in businesses, with their responsibilities varying across industries, and including tasks such as managing an office, fielding inquiries, overseeing office inventory, scheduling meetings and supervising other administrative personnel.

Summary:

A database administrator (DBA) manages computer databases. The role may include capacity planning, installation, configuration, database design, migration, performance monitoring, security, troubleshooting, as well as backup and data recovery.

Skills

Required skills for database administrators include knowledge of SQL, database queries, database theory, database design, specific databases, such as Oracle, Microsoft SQL Server, or MySQL, storage technologies, distributed computing architectures, operating systems, routine maintenance, recovery, and replication/failover.

Certification

Training for DBAs with accompanying certifications is widely available, offered by database vendors and third parties. Offerings include:

* IBM Certified Advanced Database Administrator – DB2 10.1 for Linux, Unix and Windows
* IBM Certified Database Administrator – DB2 10.1 for Linux, Unix, and Windows
* Oracle Database 12c Administrator Certified Professional
* Oracle MySQL 5.6 Database Administrator Certified Professional
* MCSA SQL Server 2012
* MCSE Data Platform Solutions Expert

Internet Forum Administrator

The administrators (short form: "admin") manage the technical details required for running the site. As such, they have the authority to appoint and revoke members as moderators, manage the rules, create sections and sub-sections, as well as perform any database operations (database backup, etc.). Administrators often also act as moderators. Administrators may also make forum-wide announcements or change the appearance (known as the skin) of a forum. There are also many forums where administrators share their knowledge.

Network administrator

A network administrator is a person designated in an organization whose responsibility includes maintaining computer infrastructures with emphasis on local area networks (LANs) up to wide area networks (WANs). Responsibilities may vary between organizations, but installing new hardware, on-site servers, enforcing licensing agreements, software-network interactions as well as network integrity and resilience are some of the key areas of focus.

System administrator

An IT administrator, system administrator, sysadmin, or admin is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems, especially multi-user computers, such as servers. The system administrator seeks to ensure that the uptime, performance, resources, and security of the computers they manage meet the needs of the users, without exceeding a set budget when doing so.

To meet these needs, a system administrator may acquire, install, or upgrade computer components and software; provide routine automation; maintain security policies; troubleshoot; train or supervise staff; or offer technical support for projects.

Details

What Is an Administrator?

An administrator is a court-appointed individual who handles all remaining financial matters for a decedent—a person who has died—during probate.

The administrator organizes all the pieces of the decedent's estate and then settles outstanding debt, expenses, and other obligations. They also distribute all remaining assets according to the decedent's will, or if there was no will (a situation called intestacy), according to a specific state's intestate succession laws.

Key Takeaways

* An administrator is an individual appointed by the court who is responsible for executing a decedent's estate.
* An administrator is responsible for settling all financial matters–including outstanding debt, expenses, and other obligations–related to a decedent's estate.
* States have different criteria outlined in their probate codes for choosing administrators.
* Administrators are chosen by a court when the decedent has not named an executor in their will or if the executor cannot carry out the responsibilities.
* The term "administrator" is used in various other contexts, such as state administrators, pension plan administrators, and third-party administrators.

Understanding the Role of Administrators

An administrator is also referred to as an executor. However, legally speaking, an administrator is appointed by a court when a decedent has not named an executor in their will or if a named executor refuses or is unable to assume the responsibilities. A court cannot force a named executor to fulfill their duties.

Depending on the state, a decedent's estate administrator is chosen based on different criteria. For example, one of the criteria specified in the state of Pennsylvania's probate code is that the administrator is chosen based on the size of their interest in a decedent's estate rather than their closeness with the deceased.

Other persons who may be considered are guardianship agencies (in cases where the decedent was incapacitated) or creditors. Persons under 18 years of age, corporations, and individuals who have an unfit background (such as a criminal record) are not considered when appointing an administrator.

The probate proceeding begins with the selection of the administrator. Once appointed, the administrator receives Letters of Testamentary issued by the court, authorizing them to discharge outstanding financial matters.

An administrator is compensated for their services based on the quality of their work and results. They are required to submit a detailed accounting of time spent and fee expenses to get paid. Professional administrators are also available for hire. These administrators generally charge a fixed fee for their services but may negotiate their rates for estates that are in excess of $1 million.

Administrator Duties

One of the first things that an administrator must do is obtain a tax identification number so they can file with the Internal Revenue Service (IRS). Then, the administrator is tasked with gathering up all of the documents and personal files that encompass the financial dealings and transactions of the decedent: bank account records, brokerage statements, credit card statements, insurance claims, tax notices, medical expense invoices, vehicle financing statements, etc.

If the decedent owned a business, the administrator takes legal title to the assets of the business and must hire a third-party appraiser to value the assets before the administrator liquidates them, pays all the business's liabilities, and finally, closes the business down. Independent valuation services must also be retained to ascertain fair market prices for real estate, art, or other illiquid personal assets.

Important : In many wills, the decedent will set aside a specific amount of cash or assets to be used as compensation for the administrator or executor.

The administrator determines if there are any tax obligations with federal and state authorities and settles them, in addition to settling any liabilities with other parties that had outstanding claims when the person died. An administrator must take particular care to clear out all of the decedents' tax claims because they can, in certain instances, be held personally responsible for unpaid taxes.

After all debts and expenses have been settled, any remaining assets are distributed by the administrator to named beneficiaries in a will. If there was no will left behind by the decedent, the assets are distributed in accordance with state procedure.

Simple probate cases may take just a few months, while complex cases can take two to three years before they are concluded.

Other Types of Administrators

The term "administrator" is a common word with different meanings depending on the situation. Some uses are as follows.

Pension Plan Administrator

A pension plan administrator is an individual or an investment management company that is responsible for the management of a retirement account or pension plan.

The plan administrator ensures that the funds are invested appropriately and with the right degrees of risk as well as distributing funds to the beneficiaries.

Some of the responsibilities of a pension plan administrator include enrolling company employees, calculating the benefit amounts, and ensuring that the funds are being invested in risk-appropriate assets.

Third-Party Administrator

A third-party administrator is any company that provides specific services on behalf of another company. A third-party administrator is one that is usually hired to complete operational tasks, including the administration of employee benefits, such as a 401(k) plan.

Third-party administrators are far-ranging in their types but can be contracted to assist with health insurance, commercial liability insurance, retirement planning, other investment services, and audits. Third-party administrators are primarily used by companies as a way to outsource a variety of administrative functions.

State Administrator

A state administrator is a government representative who enforces state regulations related to the securities industry. The Securities and Exchange Commission (SEC) enforces federal securities law while the Uniform Securities Act allows states to set their own laws.

A state administrator performs many of the same actions as the SEC, such as regulating companies and individuals, granting or suspending licenses, and generally enforcing securities law.

Example of an Administrator

Dmitri died without leaving a will and he had no surviving spouse or children. When he heard about Dmitri's death, Malik contacted the court to be appointed as his administrator. Malik applied to be Dmitri's administrator because he was a creditor to Dmitri and had loaned him funds amounting to $50,000 over the years.

Once the court approved his application, Malik set about finding more information about the state of Dmitri's finances. He inquired with Dmitri's bank and combed through his previous tax filings. Malik discovered that Dmitri did not have much money in his account but he did have a property holding that could help pay off his loan. He petitioned the court to sell off the property, settled Dmitri's tax liabilities, and paid off the remaining creditors. He was also compensated by the court for his work.

What Is the Difference Between an Administrator and an Executor?

An administrator and an executor perform the same function: the handling of all remaining financial matters for a decedent during probate. The difference is that an administrator is appointed by the court if the decedent has not named an executor in their will or if the executor is not able to carry out the required responsibilities.

How Long Does It Take to Be Appointed Administrator of an Estate?

It typically takes between six to eight weeks to receive the appropriate documentation to act as the administrator of a decedent's estate. The document needed is the "Letter of Administration" and has to be applied for.

How Much Does an Administrator of a Will Get Paid?

The amount an administrator gets paid depends on the state as well as the size of the estate. In California, for example, for an estate that is valued under $100,000, an administrator typically receives 4% of the estate's value. If the estate is valued between $100,000 and $25 million, the administrator can claim a specific percentage. If the estate is valued at over $25 million, then the court will decide the appropriate compensation.

Can an Administrator of an Estate Be a Beneficiary?

Yes, an administrator of an estate can be a beneficiary. This is common. For example, when an individual dies, their spouse, who will most likely be the beneficiary, can also act as the administrator of the estate.

The Bottom Line

An administrator manages various financial matters during probate for a decedent, an individual who has died. Typically appointed by the court, the administrator processes the decedent's debt and distributes their assets to their beneficiaries.

Jai Ganesh · 2024-11-04 00:04:17

2260) Chairman

Gist

The chair, also chairman, chairwoman, or chairperson, is the presiding officer of an organized group such as a board, committee, or deliberative assembly.

A chairman is the leader of a business meeting or group. The chairman often opens a meeting by addressing the group and explaining what the agenda will be. Charities, clubs, and the boards of companies have a chairman who acts as president or leader.

A chairman is the leader of a business meeting or group. The chairman often opens a meeting by addressing the group and explaining what the agenda will be.

Charities, clubs, and the boards of companies have a chairman who acts as president or leader. The noun chairman can refer to this person, whether male or female, though sometimes a woman is called a chairwoman. These days, it's more common still to simply call her (or him) a chair. The word chairman comes from a sense of "occupying a chair of authority," while "presiding member of a corporate body" first emerged in the 18th century.

Details

The chair, also chairman, chairwoman, or chairperson, is the presiding officer of an organized group such as a board, committee, or deliberative assembly. The person holding the office, who is typically elected or appointed by members of the group or organisation, presides over meetings of the group, and is required to conduct the group's business in an orderly fashion.

In some organizations, the chair is also known as president (or other title). In others, where a board appoints a president (or other title), the two terms are used for distinct positions. The term chairman may be used in a neutral manner, not directly implying the gender of the holder. In meetings or conferences, to "chair" something (chairing) means to lead the event.

Terminology

Look up chair, chairman, chairwoman, chairperson, or preside in Wiktionary, the free dictionary.
Terms for the office and its holder include chair, chairperson, chairman, chairwoman, convenor, facilitator, moderator, president, and presiding officer. The chair of a parliamentary chamber is sometimes called the speaker. Chair has been used to refer to a seat or office of authority since the middle of the 17th century; its earliest citation in the Oxford English Dictionary dates to 1658–1659, four years after the first citation for chairman. Feminist critiques have analysed Chairman as an example of sexist language, associating the male gender with the exercise of authority, this has led to the widespread use of the generic "Chairperson".

In World Schools Style debating, as of 2009, chairperson or chair refers to the person who controls the debate; it recommends using Madame Chair or Mr. Chairman to address the chair. The FranklinCovey Style Guide for Business and Technical Communication and the American Psychological Association style guide advocate using chair or chairperson. The Oxford Dictionary of American Usage and Style (2000) suggested that the gender-neutral forms were gaining ground; it advocated chair for both men and women. The Daily Telegraph's style guide bans the use of chair and chairperson; the newspaper's position, as of 2018, is that "chairman is correct English". The National Association of Parliamentarians adopted a resolution in 1975 discouraging the use of chairperson and rescinded it in 2017.

Usage

The word chair can refer to the place from which the holder of the office presides, whether on a chair, at a lectern, or elsewhere. During meetings, the person presiding is said to be "in the chair" and is also referred to as "the chair". Parliamentary procedure requires that members address the "chair" as "Mr. (or Madam) Chairman (or Chair or Chairperson)" rather than using a name – one of many customs intended to maintain the presiding officer's impartiality and to ensure an objective and impersonal approach.

In the British music hall tradition, the chairman was the master of ceremonies who announced the performances and was responsible for controlling any rowdy elements in the audience. The role was popularised on British TV in the 1960s and 1970s by Leonard Sachs, the chairman on the variety show The Good Old Days.

"Chairman" as a quasi-title gained particular resonance when socialist states from 1917 onward shunned more traditional leadership labels and stressed the collective control of Soviets (councils or committees) by beginning to refer to executive figureheads as "Chairman of the X Committee". Lenin, for example, officially functioned as the head of Soviet Russian government not as prime minister or as president but as "Chairman of the Council of People's Commissars". At the same time, the head of the state was first called "Chairman of the Central Executive Committee" (until 1938) and then "Chairman of the Presidium of the Presidium of the Supreme Soviet". In Communist China, Mao Zedong was commonly called "Chairman Mao", as he was officially Chairman of the Chinese Communist Party and Chairman of the Central Military Commission.

Roles and responsibilities:

Duties at meetings

In addition to the administrative or executive duties in organizations, the chair presides over meetings. Such duties at meetings include:

* Calling the meeting to order
* Determining if a quorum is present
* Announcing the items on the "order of business", or agenda, as they come up
* Recognition of members to have the floor
* Enforcing the rules of the group
* Putting questions (motions) to a vote, which is the usual way of resolving disagreements following discussion of the issues

Adjourning the meeting

While presiding, the chair should remain impartial and not interrupt a speaker if the speaker has the floor and is following the rules of the group. In committees or small boards, the chair votes along with the other members; in assemblies or larger boards, the chair should vote only when it can affect the result. At a meeting, the chair only has one vote (i.e. the chair cannot vote twice and cannot override the decision of the group unless the organization has specifically given the chair such authority).

Powers and authority

The powers of the chair vary widely across organizations. In some organizations they have the authority to hire staff and make financial decisions. In others they only make recommendations to a board of directors, or may have no executive powers, in which case they are mainly a spokesperson for the organization. The power given depends upon the type of organization, its structure, and the rules it has created for itself.

Disciplinary procedures

If the chair exceeds their authority, engages in misconduct, or fails to perform their duties, they may face disciplinary procedures. Such procedures may include censure, suspension, or removal from office. The rules of the organization would provide details on who can perform these disciplinary procedures. Usually, whoever appointed or elected the chair has the power to discipline them.

Public corporations

There are three common types of chair in public corporations.

Chairman and CEO

The chief executive officer (CEO) may also hold the title of chair, in which case the board frequently names an independent member of the board as a lead director. This position is equivalent to the position of président-directeur général in France.

Executive chair

Executive chair is an office separate from that of CEO, where the titleholder wields influence over company operations, such as Larry Ellison of Oracle, Douglas Flint of HSBC and Steve Case of AOL Time Warner. In particular, the group chair of HSBC is considered the top position of that institution, outranking the chief executive, and is responsible for leading the board and representing the company in meetings with government figures. Before the creation of the group management board in 2006, HSBC's chair essentially held the duties of a chief executive at an equivalent institution, while HSBC's chief executive served as the deputy. After the 2006 reorganization, the management cadre ran the business, while the chair oversaw the controls of the business through compliance and audit and the direction of the business.

Non-executive chair

Non-executive chair is also a separate post from the CEO; unlike an executive chair, a non-executive chair does not interfere in day-to-day company matters. Across the world, many companies have separated the roles of chair and CEO, saying that this move improves corporate governance. The non-executive chair's duties are typically limited to matters directly related to the board, such as:

* Chairing the meetings of the board.
* Organizing and coordinating the board's activities, such as by setting its annual agenda.
* Reviewing and evaluating the performance of the CEO and the other board members.

Examples

Many companies in the US have an executive chair; this method of organization is sometimes called the American model. Having a non-executive chair is common in the UK and Canada; this is sometimes called the British model. Expert opinion is rather evenly divided over which is the preferable model. There is a growing push by public market investors for companies with an executive chair to have a lead independent director to provide some element of an independent perspective.

The role of the chair in a private equity-backed board differs from the role in non-profit or publicly listed organizations in several ways, including the pay, role and what makes an effective private-equity chair. Companies with both an executive chair and a CEO include Ford, HSBC, Alphabet Inc., and HP.

Vice-chair and deputy chair

A vice- or deputy chair, subordinate to the chair, is sometimes chosen to assist and to serve as chair in the latter's absence, or when a motion involving the chair is being discussed. In the absence of the chair and vice-chair, groups sometimes elect a chair pro tempore to fill the role for a single meeting. In some organizations that have both titles, deputy chair ranks higher than vice-chair, as there are often multiple vice-chairs but only a single deputy chair. This type of deputy chair title on its own usually has only an advisory role and not an operational one (such as Ted Turner at Time Warner).

An unrelated definition of vice- and deputy chairs describes an executive who is higher ranking or has more seniority than an executive vice-president (EVP).

Jai Ganesh · Yesterday 00:12:45

2261) Nursing Home

Gist

A nursing home is a public or private residential facility providing a high level of long-term personal and nursing care for persons (such as the aged or the chronically ill) who are unable to care for themselves properly.

Today nursing homes have a more active role in health care, helping patients prepare to live at home or with a family member when possible. They help conserve expensive hospital facilities for the acutely ill and improve the prospects of the chronically disabled.

Summary

Nursing home is a facility for care (usually long-term) of patients who are not sick enough to need hospital care but are not able to remain at home. Historically, most residents were elderly or ill or had chronic irreversible and disabling disorders, and medical and nursing care was minimal. Today nursing homes have a more active role in health care, helping patients prepare to live at home or with a family member when possible. They help conserve expensive hospital facilities for the acutely ill and improve the prospects of the chronically disabled. However, quality of care varies widely, and the potential for abuse exists.

Details

A nursing home is a facility for the residential care of older people, senior citizens, or disabled people. Nursing homes may also be referred to as care homes, skilled nursing facilities (SNF) or long-term care facilities. Often, these terms have slightly different meanings to indicate whether the institutions are public or private, and whether they provide mostly assisted living, or nursing care and emergency medical care. Nursing homes are used by people who do not need to be in a hospital, but require care that is hard to provide in a home setting. The nursing home staff attends to the patients' medical and other needs. Most nursing homes have nursing aides and skilled nurses on hand 24 hours a day.

In the United States, while nearly 1 in 10 residents aged 75 to 84 stays in a nursing home for five or more years, nearly 3 in 10 residents in that age group stay less than 100 days, the maximum duration covered by Medicare, according to the American Association for Long-Term Care Insurance. Some nursing homes also provide short-term rehabilitative stays following surgery, illness, or injury. Services may include physical therapy, occupational therapy, or speech-language therapy. Nursing homes also offer other services, such as planned activities and daily housekeeping. Nursing homes may offer memory care services, often called dementia care.

History

Poorhouses/workhouses were the first implemented national framework to provide a basic level of care to the old and infirm. Pictured, is "The workroom at St James's workhouse" from The Microcosm of London (1808).
From before the 17th century to modern day, many families care for their elders in the family's home. While this is still common practice for many communities and families around the world, this has become increasingly more difficult over time as life expectancy increases, family size decreases, and increased expertise in caring for a person with a chronic disease is needed. In the 21st century, nursing homes have become a standard form of care for most aged and incapacitated persons to account for those complexities. Nearly 6 percent of older adults are sheltered in residential facilities that provide a wide range of care. Yet such institutions have not always existed; rather, their history and development reflect relatively recent demographic and political realities that shape the experience of growing old.

In the 17th century, poorhouses (also referred to as almshouses) originated in England as municipalities were expected to care for their poor. Orphans, people determined to be mentally ill, and elderly people were often placed into these living commons while able-bodied individuals were expected to work and could be imprisoned if they refused. This model was brought to North America by English settlers. Before the 19th century, no age-restricted institutions existed for long-term care; elderly individuals, who needed shelter because of incapacity, impoverishment, or family isolation, often ended their days in an almshouse. Placed alongside people deemed insane, people who were inebriated, or people who were homeless, they were simply categorized as part of the community's most needy recipients. Poorhouses gave a place where they could be given shelter and daily meals.

In the 1800s in the US, women's and church groups began to establish special homes for elderly people. Often concerned that individuals of their own ethnic or religious communities might die alongside the most despised society, this led to the creation of private care facilities for the elderly in these communities. Poorhouses continued to exist into the early 20th century, despite the criticism of the poor conditions of the poorhouses. In the US, the Great Depression overwhelmed the poorhouses, leading to not enough space and funding. Due to muckraking in the 1930s, the less-than-favorable living conditions of the poorhouses were exposed to the public. This led to the provision of the Social Security Act (1935) to only give people their pension if they did not live in poorhouses, but could live in private institutions.

In the US, poorhouses were then replaced with residential living homes, known as board-and-care homes or convalescent homes. These board-and-care homes provided basic levels of care and meals in a private setting for a specific fee. Board-and-care homes proved to be a success and by World War II, the new way of nursing homes began to take shape. As the times continued to change, the government identified the issue of people spending extensive amounts of time in hospitals. To combat these long stays in short-term settings, board-and-care homes began to convert into something more public and permanent that was state and federally funded. From this, by 1965 nursing homes were a solid fixture. Nursing homes were a permanent residence where the elderly and disabled could receive any necessary medical care and receive daily meals. These nursing homes showed improvement in maintaining care and cleanliness standards in comparison to almshouses and poorhouses. From the 1950s through the 1970s, the dynamics of nursing homes began changing significantly. In the United States, Medicare and Medicaid began to make up much of the money that would filter through the homes and the 1965 amendment laws enforced nursing homes to comply with safety codes and required registered nurses to be on hand at all times. Additionally, nursing homes may sue children for the costs of caring for their parents in jurisdictions which have filial responsibility laws. Later in 1987, in the US the Nursing Reform Act was introduced to begin defining the different types of nursing home services and later added the Residents' Bill of Rights.

In the UK, after World War II many soldiers and civilians needing hospital care due to casualties during the war were placed in the hospital along with the many elderly patients present there, leading to overcrowding. The implementation of the NHS in 1948 and the abolishment of the Old Poor Law allowed for the creation of what would become modern day, public nursing homes. In the 1950s, Professor Peter Townsend brought to light the discrepancies the standard of care between the publicly and privately funded cares homes, leading to health policy reforms that assured the standard care practices for the elderly living in NHS funded care homes. The 1980s and 1990s saw care homes becoming a large industry in the UK. Thus, policies ensuring that private care homes are regulated (Registered Homes Act 1984) and patient needs are met (Care Standards Act of 2000) were established.

Today, nursing homes are varied. Some nursing homes still resemble a hospital while others look more like a home. Nursing home residents can pay for their care out of pocket or with government assistance. In the US, others may receive Medicare for a short time, while in other countries, public assistance may be available, and some may use long-term insurance plans. Across the spectrum, most nursing homes in the US will accept Medicaid as a source of payment.

Considerations

Below are a few reasons to consider a nursing home:

* Managing a worsening and progressive disease such as Alzheimers.
* Care after a recent hospital admission and not ready to transition to independently caring for oneself at home.
* When medical needs at home become unmanageable by the primary caregiver at home.
* When activities and socialization with people of similar age is deprived.
* When primary caregiver at home do not have the proper knowledge of the nutrition needed.

When looking into nursing homes, consider what activities and/or medical needs patients one would need from the nursing home. Also consider finances, such as medical insurance and personal funds. Ensure the nursing home is properly licensed and has qualified staff. If time allows, visit the nursing home in person to receive a walk through of the facility and if given the opportunity to speak with a guest or family member of guest, ask about their experience thus far.

Staff

Nursing home employees are all required to be licensed or uphold a certificate in the state of which they work. In most facilities, nursing homes are required to provide enough staff to adequately care for residents. In the US, for instance, nursing homes must have at least one registered nurse (RN) available for at least 8 straight hours a day throughout the week, and at least one licensed practical nurse (LPN) on duty 24 hours a day. Direct care nursing home employees usually include registered nurses, licensed practical nurses, social workers, certified nursing assistants, and physical therapists, amongst others.

Medical staff:

Nurses

Nursing homes require assessment and monitoring of residents by a registered nurse (RN) who is typically required to have between two and six years of education. The RN's job duties include implementing care plans, administering medications, recording and maintaining accurate reports for each resident, monitoring and recording medical changes, and providing direction to the nursing assistants and licensed practical nurses (LPN). RNs are not required to choose a specialization. To gain recognition as a specialized nurse professional, RNs typically need education in their specialized field, and further experience through clinical practices. LPNs are typically required to have a year of training before working with any patients. The LPN monitors residents' well-being and administers treatments and medications, such as dressing wounds and dispensing prescribed drugs. LPNs are responsible for patients' direct bed care and carry out a daily routine.

Nursing assistants

A nursing assistant provides basic care to patients while working directly under a LPN or RN. These basic care activities, also referred to as activities of daily living, can include assisting with bathing and dressing residents, helping residents with meals, either serving them or with feeding, transferring to and from the bed or wheelchair, making and cleaning beds, assisting with toileting, and answering call lights. Nursing assistants' official titles can vary between jurisdictions and facilities. They can include Certified Nursing Assistants (CNAs), nursing aides, caregivers, patient care associates, patient care technicians, personal care attendants (PCAs), and care assistants.

Physicians

At skilled nursing facilities, in addition to required 24 hour skilled nursing, a licensed physician supervises individual patients. At nursing homes other than skilled nursing facilities, patients receive care from physicians not affiliated with the nursing home. These physicians are typically employed by a private agency that sends physicians to nursing homes per the request of the patient, nursing home, or patient's family. The majority of these physicians are family medicine doctors or internists; however, some specialists such as cardiologist or nephrologist may also make independent visits to supplement their care.

Non-medical staff:

Administration

Depending on the size of the nursing home, a nursing home may have either a nursing home administrator or an executive director. Some nursing homes may have both, but their job duties are similar and can include overseeing staff, supplying medical supplies, and financial matters. Some nursing homes also have human resources personnel, who are in charge of all aspects of hiring new employees. Human resources job duties vary but can also include coordinating payroll, organizing orientation programs for new employees, interviewing, disciplinary actions, and ensuring compliance with federal and state laws. Nursing homes are usually licensed and heavily regulated under governing legislation. Compliance with the federal and state legislatures are reviewed regularly for adherence to strict standards of building codes, care plans, behavior and altercations between residents, nutrition and dietary services, medical services, nursing and personal care, religious and spiritual practices, pets, and recreational programs.

Housekeeping

Housekeepers perform everyday cleaning and upkeep in nursing homes. They play a huge part in ensuring that nursing homes are kept clean and free of disease causing agents. Housekeepers have a long list of duties which include cleaning floors, changing linens, disinfecting bathrooms, changing towels, washing clothes, emptying trashcans, sanitizing rooms, replenishing supplies, dusting, vacuuming, and keeping windows and woodwork clean. These duties can vary from facility to facility but it will overall include basic cleaning. Housekeeping does not require any licensure or schooling, but some jobs may prefer experienced housekeepers.

Recreational staff

Recreational staff usually include an activity director and possibly activity assistants depending on the size of the nursing home. Activities aim to meet each resident's emotional, intellectual, physical, social, spiritual, and vocational needs. The transition from being independent to having to depend on others and be away from home is oftentimes very difficult, which is why activities are important to combat depression and anxiety. Some of the different activities that may be offered include hosting birthday parties, celebrating holidays, book clubs, musical events, outdoor activities, discussion and social groups, exercise, arts and crafts, pet therapy, religious services and community outings. Volunteer involvement is also an important part of nursing home activities given that volunteers can act as a link between the nursing home and the outside community.

Additional Information

As the United States population continues to age, the need for quality elder care will grow. One common living option for those who require a high level of care is a nursing home. Nursing homes are complex healthcare facilities with different departments dedicated to maintaining the physical, psychological, and emotional health of their residents. The Centers for Disease Control and Prevention (CDC) reported in 2016 that there were 15,600 nursing homes in the U.S., with about 1.7 million total beds.

To support all of their patients, nursing homes employ a diverse group of professionals. These employees may specialize in business, healthcare, or other disciplines. Working in a nursing home is a unique experience. In these environments, professionals with different skill sets collaborate with one another to improve the lives of senior community members. Continue reading to explore why nursing homes are rewarding work environments and the professional opportunities they offer.

What Are Nursing Homes Like?

No matter what hour of the day or night, there are nursing home employees awake and tending to the needs of residents. There’s often a great deal of activity, such as nurses making their rounds, maintenance staff preparing the facility for the next day’s activities, or finance professionals balancing the budgets. At their busiest hours, the halls and wings of nursing homes are full of movement, with residents heading out to activities, visitors stopping in, and staff members performing their daily tasks.

Jobs in nursing homes often fall into one of three categories: administration, direct care, and support.

Administration

Administrative professionals keep nursing homes running efficiently. They’re responsible for managing other employees, working with patients’ health insurance companies, and paying facility bills. Administrative positions in nursing homes include business roles such as marketing director, finance director, human resources specialist, accounts payable, and receptionist. These positions do not directly interact with residents, and some nursing homes house administrative staff in separate buildings.

Direct Care Staff

The direct care staff consists of those directly responsible for patient care. Registered nurses (RNs) represent the largest percentage of the direct care staff, as nursing homes have skilled nurses on the clock at all times working under the direction of one or more physicians. These RNs might also have nursing assistants or medical technicians assisting them. The direct care staff at nursing homes also includes therapeutic and recreational personnel, such as physical therapists, recreational therapists, activities directors, and other professionals who keep patients active and their quality of life high.

Support Staff

Support staff can include janitorial, maintenance, landscaping, and transportation personnel. These employees typically have minimal contact with facility residents but may receive specialized training on how to perform jobs in the context of a healthcare facility, as they will be among people with vulnerable medical conditions.

What Are the Benefits of Working in a Nursing Home?

Each day and night, thousands of administrators, direct care staff, and support staff wake up and head to their jobs at nursing homes. When asked, “why did you want to work in a nursing home?” many would respond that they find their careers fulfilling for a host of different reasons. From helping those in need to learning from the wisdom of seniors in their care, working in a nursing home has many benefits to offer.

Helping People in Need

Working in a nursing home means providing healthcare for people who need it. Nursing homes provide seniors with a safe, clean, healthy environment where they can receive the care they need, access proper nutrition, and experience the social benefits of being around their peers. Nursing home employees have the satisfaction of providing such care and attention, knowing they’re making a difference in the lives of their residents.

Learning About Life

Working around people in the later stages of life can teach nursing home employees valuable lessons about the aging process, the mindset of the elderly, and what it means to age. The senior members of any community have a wealth of knowledge and wisdom to share. While some fear aging, the elderly can illustrate that it’s a natural part of life and that one’s later years can be enjoyable.

Teamwork Environment

Nursing homes rely on an interdisciplinary staff to ensure operations run smoothly and provide high-quality care. As such, all nursing home employees learn what it means to work as part of a team. Each staff member at a nursing home fulfills a specific, valuable role. In most of these positions, employees work with professionals in other areas as well as with members of their own departments, thereby providing them with the opportunity to develop their communication and collaboration skills.

A Professional Future in Caring for the Elderly

There are a lot of great reasons to work in a nursing home. It means stepping into a fulfilling career in which you can provide essential care to the most senior members of your community. The U.S. Bureau of Labor Statistics (BLS) projects the healthcare field to grow by 3.3 million jobs between 2018 and 2028, making work in a nursing home environment not just rewarding but also increasingly in demand. Find out more about how Maryville University’s online bachelor’s in healthcare management with a certificate in senior living management can help you land a great job in this important field.

Jai Ganesh · Today 00:08:49

2262) Boron Nitride

Gist

Boron Nitride, (chemical formula BN), synthetically produced crystalline compound of boron and nitrogen, is an industrial ceramic material of limited but important application, principally in electrical insulators and cutting tools.

What is boron nitride used for?

BN nanostructures are used for thermal conductivity enhancement, mechanical strength enhancement, insulating coatings, oxidation and corrosion-resistant coatings, electrical circuits, water treatment, and hydrogen storage.

Summary

The empirical formula of boron nitride (BN) is deceptive. BN is not at all like other diatomic molecules such as carbon monoxide (CO) and hydrogen chloride (HCl). Rather, it has much in common with carbon, whose representation as the monatomic C is also misleading.

BN, like carbon, has multiple structural forms. BN’s most stable structure, hBN, is isoelectronic with graphite and has the same hexagonal structure with similar softness and lubricant properties. hBN can also be produced in graphene-like sheets that can be formed into nanotubes.

In contrast, cubic BN (cBN) is isoelectronic with diamond. It is not quite as hard, but it is more thermally and chemically stable. It is also much easier to make. Unlike diamond, it is insoluble in metals at high temperatures, making it a useful abrasive and oxidation-resistant metal coating. There is also an amorphous form (aBN), equivalent to amorphous carbon.

BN is primarily a synthetic material, although a naturally occurring deposit has been reported. Attempts to make pure BN date to the early 20th century, but commercially acceptable forms have been produced only in the past 70 years. In a 1958 patent to the Carborundum Company (Lewiston, NY), Kenneth M. Taylor prepared molded shapes of BN by heating boric acid (H3BO3) with a metal salt of an oxyacid such as phosphate in the presence of ammonia to form a BN “mix”, which was then compressed into shape.

Today, similar methods are in use that begin with boric trioxide (B2O3) or H3BO3 and use ammonia or urea as the nitrogen source. All synthetic methods produce a somewhat impure aBN, which is purified and converted to hBN by heating at temperatures higher than used in the synthesis. Similarly, to the preparation of synthetic diamond, hBN is converted to cBN under high pressure and temperature.

Details

Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula BN. It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form corresponding to graphite is the most stable and soft among BN polymorphs, and is therefore used as a lubricant and an additive to cosmetic products. The cubic (zincblende aka sphalerite structure) variety analogous to diamond is called c-BN; it is softer than diamond, but its thermal and chemical stability is superior. The rare wurtzite BN modification is similar to lonsdaleite but slightly softer than the cubic form.

Because of excellent thermal and chemical stability, boron nitride ceramics are used in high-temperature equipment and metal casting. Boron nitride has potential use in nanotechnology.

Structure

Boron nitride exists in multiple forms that differ in the arrangement of the boron and nitrogen atoms, giving rise to varying bulk properties of the material.

Amorphous form (a-BN)

The amorphous form of boron nitride (a-BN) is non-crystalline, lacking any long-distance regularity in the arrangement of its atoms. It is analogous to amorphous carbon.

All other forms of boron nitride are crystalline.

Hexagonal form (h-BN)

The most stable crystalline form is the hexagonal one, also called h-BN, α-BN, g-BN, and graphitic boron nitride. Hexagonal boron nitride has a layered structure similar to graphite. Within each layer, boron and nitrogen atoms are bound by strong covalent bonds, whereas the layers are held together by weak van der Waals forces. The interlayer "registry" of these sheets differs, however, from the pattern seen for graphite, because the atoms are eclipsed, with boron atoms lying over and above nitrogen atoms. This registry reflects the local polarity of the B–N bonds, as well as interlayer N-donor/B-acceptor characteristics. Likewise, many metastable forms consisting of differently stacked polytypes exist. Therefore, h-BN and graphite are very close neighbors, and the material can accommodate carbon as a substituent element to form BNCs. BC6N hybrids have been synthesized, where carbon substitutes for some B and N atoms. Hexagonal boron nitride monolayer is analogous to graphene, having a honeycomb lattice structure of nearly the same dimensions. Unlike graphene, which is black and an electrical conductor, h-BN monolayer is white and an insulator. It has been proposed for use as an atomic flat insulating substrate or a tunneling dielectric barrier in 2D electronics.

Cubic form (c-BN)

Cubic boron nitride has a crystal structure analogous to that of diamond. Consistent with diamond being less stable than graphite, the cubic form is less stable than the hexagonal form, but the conversion rate between the two is negligible at room temperature, as it is for diamond. The cubic form has the sphalerite crystal structure, the same as that of diamond (with ordered B and N atoms), and is also called β-BN or c-BN.

Wurtzite form (w-BN)

The wurtzite form of boron nitride (w-BN) has the same structure as lonsdaleite, a rare hexagonal polymorph of carbon. As in the cubic form, the boron and nitrogen atoms are grouped into tetrahedra. In the wurtzite form, the boron and nitrogen atoms are grouped into 6-membered rings. In the cubic form all rings are in the chair configuration, whereas in w-BN the rings between 'layers' are in boat configuration. Earlier optimistic reports predicted that the wurtzite form was very strong, and was estimated by a simulation as potentially having a strength 18% stronger than that of diamond. Since only small amounts of the mineral exist in nature, this has not yet been experimentally verified. Its hardness is 46 GPa, slightly harder than commercial borides but softer than the cubic form of boron nitride.

Properties:

Physical

The partly ionic structure of BN layers in h-BN reduces covalency and electrical conductivity, whereas the interlayer interaction increases resulting in higher hardness of h-BN relative to graphite. The reduced electron-delocalization in hexagonal-BN is also indicated by its absence of color and a large band gap. Very different bonding – strong covalent within the basal planes (planes where boron and nitrogen atoms are covalently bonded) and weak between them – causes high anisotropy of most properties of h-BN.

For example, the hardness, electrical and thermal conductivity are much higher within the planes than perpendicular to them. On the contrary, the properties of c-BN and w-BN are more homogeneous and isotropic.

Those materials are extremely hard, with the hardness of bulk c-BN being slightly smaller and w-BN even higher than that of diamond. Polycrystalline c-BN with grain sizes on the order of 10 nm is also reported to have Vickers hardness comparable or higher than diamond. Because of much better stability to heat and transition metals, c-BN surpasses diamond in mechanical applications, such as machining steel. The thermal conductivity of BN is among the highest of all electric insulators.

Boron nitride can be doped p-type with beryllium and n-type with boron, sulfur, silicon or if co-doped with carbon and nitrogen. Both hexagonal and cubic BN are wide-gap semiconductors with a band-gap energy corresponding to the UV region. If voltage is applied to h-BN or c-BN, then it emits UV light in the range 215–250 nm and therefore can potentially be used as light-emitting diodes (LEDs) or lasers.

Little is known on melting behavior of boron nitride. It degrades at 2973 °C, but melts at elevated pressure.

Thermal stability

Hexagonal and cubic BN (and probably w-BN) show remarkable chemical and thermal stabilities. For example, h-BN is stable to decomposition at temperatures up to 1000 °C in air, 1400 °C in vacuum, and 2800 °C in an inert atmosphere.

Thermal stability of c-BN can be summarized as follows:

* In air or oxygen: B2O3 protective layer prevents further oxidation to ~1300 °C; no conversion to hexagonal form at 1400 °C.
* In nitrogen: some conversion to h-BN at 1525 °C after 12 h.
* In vacuum ({10}^{-5} Pa): conversion to h-BN at 1550–1600 °C.

Mechanical properties

BN nanosheets consist of hexagonal boron nitride (h-BN). They are stable up to 800°C in air. The structure of monolayer BN is similar to that of graphene, which has exceptional strength, a high-temperature lubricant, and a substrate in electronic devices.

The anisotropy of Young's modulus and Poisson's ratio depends on the system size. h-BN also exhibits strongly anisotropic strength and toughness, and maintains these over a range of vacancy defects, showing that the anisotropy is independent to the defect type.

Additional Information

Boron Nitride, (chemical formula BN), is a synthetically produced crystalline compound of boron and nitrogen, an industrial ceramic material of limited but important application, principally in electrical insulators and cutting tools. It is made in two crystallographic forms, hexagonal boron nitride (H-BN) and cubic boron nitride (C-BN).

H-BN is prepared by several methods, including the heating of boric oxide (B2O3) with ammonia (NH3). It is a platy powder consisting, at the molecular level, of sheets of hexagonal rings that slide easily past one another. This structure, similar to that of the carbon mineral graphite, makes H-BN a soft, lubricious material; unlike graphite, though, H-BN is noted for its low electric conductivity and high thermal conductivity. H-BN is frequently molded and then hot-pressed into shapes such as electrical insulators and melting crucibles. It also can be applied with a liquid binder as a temperature-resistant coating for metallurgical, ceramic, or polymer processing machinery.

C-BN is most often made in the form of small crystals by subjecting H-BN to extremely high pressure (six to nine gigapascals) and temperature (1,500° to 2,000° C, or 2,730° to 3,630° F). It is second only to diamond in hardness (approaching the maximum of 10 on the Mohs hardness scale) and, like synthetic diamond, is often bonded onto metallic or metallic-ceramic cutting tools for the machining of hard steels. Owing to its high oxidation temperature (above 1,900° C, or 3,450° F), it has a much higher working temperature than diamond (which oxidizes above 800° C, or 1,475° F).

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