332) Adipose Tissue

Adipose tissue, or fatty tissue, connective tissue consisting mainly of fat cells (adipose cells, or adipocytes), specialized to synthesize and contain large globules of fat, within a structural network of fibres. It is found mainly under the skin but also in deposits between the muscles, in the intestines and in their membrane folds, around the heart, and elsewhere. It is also found in the bone marrow, where it imparts a yellow colour; yellow marrow is most abundant in adults. The fat stored in adipose tissue comes from dietary fats or is produced in the body.

Mammals have two different types of adipose: white adipose tissue and brown adipose tissue. White adipose, the most common type, provides insulation, serves as an energy store for times of starvation or great exertion, and forms pads between organs. When muscles and other tissues need energy, certain hormones bind to adipose cells and trigger the hydrolysis of triacylglycerol, resulting in the release of energy-rich fatty acids and glycerol—a process known as lipolysis. The enzyme responsible for hydrolysis is lipase, which occurs in the blood, certain gastrointestinal juices, and adipose tissue. Lipase is activated by the hormones epinephrine, norepinephrine, glucagon, and adrenocorticotropin, which bind to adipocytes.

White adipose tissue also is a source of a number of different hormones, which serve various roles in metabolism and endocrine function. The adipose-produced hormones adiponectin, leptin, and resistin are involved in energy metabolism, for example, whereas plasminogen activator inhibitor-1 prevents the dissolution of blood clots.

Brown adipose, found mainly in newborn animals, generates heat and actually consumes energy. In humans, the percentage of brown adipose found in the body decreases with age. In other animals, however, particularly those that hibernate (e.g., grizzly bears and black bears), it is found in adults and plays an important role in survival. Species that hibernate experience a drop in body temperature and a slowing of metabolism during winter dormancy, which allows them to conserve energy. Brown adipose, by consuming energy, releases heat, which is vital for awakening and emergence from dormancy. Brown adipose tissue typically is tan to red in colour. Its colour and heat-generating properties are imparted by the abundance of organelles known as mitochondria found in brown fat cells. (Mitochondria are the energy-producing components of cells.)

In humans, the distribution of adipose tissue in the body can vary depending on gender. In general, men accumulate fat around the waist, and women tend to accumulate more fat around the hips than the waist. Geneticists have located distinct regions in the human genome that are associated with fat distribution, and several genes in particular appear to have a greater influence on waist-to-hip ratio in women than in men. Because these genes are involved in regulating the activities of fat cells, knowledge of their precise functions could provide insights into the biological mechanisms underlying obesity, diabetes mellitus, and cardiovascular disease.

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M # 511. If the radius of a circle is 6 centimeters and the length of an arc is 12 centimeters, find the area of the sector.

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The solution #7392 is correct. Excellent, Monox D. I-Fly!

#7393. The sum of 15% of a positive number and 10% of the same number is 70. What is twice that number?

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#7211. Name the French writer (24 July 1802 – 5 December 1870). His works have been translated into many languages, and he is one of the most widely read French authors. Many of his historical novels of high adventure were originally published as serials, including 'The Count of Monte Cristo', 'The Three Musketeers', 'Twenty Years After', and 'The Vicomte of Bragelonne: Ten Years Later'. His novels have been adapted since the early twentieth century for nearly 200 films.

#7212. In Norse mythology, it is a burning rainbow bridge that reaches between Midgard (Earth) and Asgard, the realm of the gods. What is it?

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The solution #7391 is correct. Neat work, Monox D. I-Fly!

#7392. The difference between 89% of a number and 73% of the same number is 448. What is 49% of that number?

507) Martin van Marum

Martin(us) van Marum (20 March 1750, Delft – 26 December 1837, Haarlem) was a Dutch physician, inventor, scientist and teacher, who studied medicine and philosophy in Groningen. Van Marum introduced modern chemistry in the Netherlands after the theories of Lavoisier, and several scientific applications for general use. He became famous for his demonstrations with instruments, most notable the ‘Large electricity machine’, to show statical electricity and chemical experiments while curator for the Teylers Museum.

Biography

Early career

Born in Delft, Van Marum moved to Haarlem in 1776 ‘because the Haarlemmers had more taste in the sciences than anywhere else in the Netherlands’. After his arrival in Haarlem he began to practise medicine, but devoted himself mainly to lecturing on physical subjects and creating instruments to demonstrate physical theory. He must have made a big impression on Haarlem society, because he became a member of the Dutch Society of Science in the same year, but was named director and curator of their cabinet of curiosities in the next year.

Van Marum received at first no salary, but by scaring off the former cabinet concierge Nicolaus Linder, he was able to collect Linder's' salary of 100 guilders, and when the cabinet moved later in 1777 to new quarters in the Grote Houtstraat 51, van Marum lived there as concierge. He managed to scare off Linder by obtaining permission from the society to allow his servants to keep tips they received from cabinet visitors; a source of income that Linder had come to rely on. Then van Marum increased this salary to 300 from 100 by adding responsibilities to his list of duties, such as a summer garden in the Rozenprieel and eliminating other expenses.

Curator of two museums

In 1779 he was entrusted with the care of the ‘Second society’ left to Haarlem by Pieter Teyler van der Hulst (1702–1778), which led under his direction to the foundation of the Teylers Museum. The Teyler legacy was split into three societies, one for religion, one for science, and one for the arts, known as the first, second, and third societies. The caretakers had to meet in Teyler's home weekly, and each society had 5 caretakers, so all of the gentlemen involved lived in Haarlem.

In 1794 van Marum became secretary as well as director of the Dutch Society of Science. Under his management, both societies were advanced to the position of the most noted in Europe. Period travelogues mention both Museums.

Besides being involved with the ‘Hollandsche Maatschappij der Wetenschappen’, he was an ordinary member (5 December 1776) and a corresponding member (from 25 December 1776) of the 'Provinciaal Utrechtsch Genootschap van Kunsten en Wetenschappen', a member of the 'Bataafsch Genootschap der Proefondervindelijke wijsbegeerte' from 1784, a member of the 'Zeeuwsch Genootschap der Wetenschappenfrom' 27 August 1782, corresponding member of the 'Académie des Sciences' from 1783, and a member of the ‘Vergadering van Notabelen voor het departement Zuiderzee’ from 29 March 1814. In 1808 he was asked by Louis Bonaparte to be a member of the committee for the formation of the Koninklijk Instituut along with Jeronimo de Bosch, Jean Henri van Swinden, and Martinus Stuart. He became member of the institute the same year.

Merging societies, separate collections

Under his guidance the two societies slowly merged. His name is associated with the ‘Electriseermachine’, the largest electricity demonstration machine with Leiden jars built in the 18th century and at the time a crowd pleaser for the young Teylers museum. The demonstration model is still on display, as is a smaller version in the Museum Boerhaave of Leiden. Van Marum's researches (especially in connection with electricity) were remarkable for their number and variety.

The Teyler's Museum kept its role as a museum of scientific research (some of the periodical subscriptions he started are still running) and is a repository of important scientific demonstration models from the period. Not only items regarding electricity, but also weather stations, industrial models, steam engines, and other examples of the budding industrial revolution were collected and lovingly displayed. The collection of the Teyler's was mostly based on scientific theory, while the collection of the Dutch Society of Science was mostly based on scientific practise. The rooms in the Grote Houtstraat were filled with stuffed animals and other "naturalia", while the summer garden was a modern continuation of Linder's old Linnaeus hortus once located behind the original city hall quarters in the Prinsenhof. Since Linder had not known any Latin, it was easier for Van Marum to entertain foreign visitors with stories of Linnaean trivia and of course, the Haarlem story of tulip mania.

Teylers Museum

In 1784, when the Teylers Museum opened its new 'Oval Room', the artist Vincent Jansz van der Vinne was hired as curator of the art collection and lived in Pieter Teyler's former residence that was called the "Fundatiehuis" as concierge and caretaker of the art collection. He left the next year because of continuous disagreements with van Marum over art and the opening hours of the museum.

Van der Vinne was an artist born into an important Haarlem artist family – he was the great-grandson of Vincent van der Vinne. The Teyler's museum replaced him with another local artist, Wybrand Hendricks, who painted the famous oval room and many other Haarlem scenes. Hendricks is largely responsible for the Teyler's collection of Old Master prints, most notably the purchase in Rome 1790 of a print & drawing collection formerly owned by Christina of Sweden. Apparently he got along under van Marum, but when he left in 1819 at the age of 75, the Teyler's decided to discontinue the purchase of art "for the decline in art enthusiasts in this city".

During the tenure of Hendriks, van Marum himself was busy giving public demonstrations of electricity in the Oval room, but was also collecting in this period (this is why he was so involved with the lifestyle of the concierge of the Fundatiehuis, since he was there every day). He concentrated on scientific publications for the Teyler library. He concentrated his efforts on three aspects: 1) Greek and Latin authors, among them the church fathers, 2) Works of natural history including travelogues, and 3) natural history periodicals, including all publications of the Royal Society of London and all publications of the Dutch Society of Science, which Teyler had been a member of, but could not be on the board of, due to religious differences with the board. The criteria for purchase was always expense. If a Society member could afford to purchase it himself it was not worth adding to the collection. Any member could suggest purchases, however, which explains why the collection is filled with richly illustrated examples of contemporary publications. The most impressive of these are the large illustrated books of travellers. To view the collection, van Marum organised ‘gentleman evenings’ in Pieter Teyler's library, a tradition that still exists.

Legacy

Though the public is allowed access during the day to the museum rooms, the private rooms of Pieter Teyler in the "Fundatiehuis" are only open one day a year, on Monument Day. Because of its rich scientific tradition, many noted scholars of Physics moved to Haarlem to work at Teyler's, including Nobel prize winners Pieter Zeeman and Hendrik Lorentz.

Of van Marum's three categories, only the first was discontinued at the close of the 19th century. The collection of periodicals which has been expanded through exchange networks, contains uninterrupted series that are among the oldest in the world.

The Teyler's museum created a new wing in 1996 to house a rotational display of van Marum's library collection, such as the works of John James Audubon in combination with contemporary stuffed birds of Naturalis.

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Good attempt, Monox D. I-Fly!

#4449. The largest and the second largest angles of a triangle are in the ratio 13 : 12. The smallest angle is 20% of the sum of the largest and the second largest angles. What is the sum of the smallest and the second largest angles?

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The solution #7389 is correct. Neat work, Monox D. I-Fly!

#7390. 56% of a number is 1064. What is 38% of that number?

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Good attempt, Monox D. I-Fly!

M # 510. What is the diameter of a circle whose area is equal to the areas of two circles of radii 40 centimeters and 9 centimeters?

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#3197. What does the adjective derivative mean?

#3198. What does the noun dermatitis (Pathology) mean?

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M # 509. Find the perimeter of a sector of a circle whose radius is 7 centimeters and central angle is

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The solution #7388 is correct. Neat work, Monox D. I-Fly!

#7389. Evaluate: (take positive square roots only)