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Watching stem cells repair the human brain

Thu, 20 Aug 2009 01:30:37 GMT

There is no known cure for neurodegenerative diseases such as Huntington's, Alzheimer's and Parkinson's. But new hope, in the form of stem cells created from the patient's own bone marrow, can be found ― and literally seen ― in laboratories at Tel Aviv University.

Dr. Yoram Cohen of TAU's School of Chemistry has recently proven the viability of these innovative stem cells, called mesenchymal stem cells, using in-vivo MRI. Dr. Cohen has been able to track their progress within the brain, and initial studies indicate they can identify unhealthy or damaged tissues, migrate to them, and potentially repair or halt cell degeneration. His findings have been reported in the journal Stem Cells.

"By monitoring the motion of these cells, you get information about how viable they are, and how they can benefit the tissue," he explains. "We have been able to prove that these stem cells travel within the brain, and only travel where they are needed. They read the chemical signalling of the tissue, which indicate areas of stress. And then they go and try to repair the situation."

Tracking live cells in the brain

To test the capabilities of this innovative new stem cells, Dr. Cohen created a study to track the activity of the live cells within the brain using the in-vivo MRI at the Strauss Centre for Computational Neuro-Imaging. Watching the live, active cells has been central to establishing their viability as a therapy for neurodegenerative disease.

Dr. Cohen and his team of researchers took magnetic iron oxide nanoparticles and used them to label the stem cells they tested. When injected into the brain, they could then be identified as clear black dots on an MRI picture. The stem cells were then injected into the brain of an animal that had an experimental model of Huntington's disease. These animals suffer from a similar neuropathology as the one seen in human Huntington's patients, and therefore serve as research tool for the disease.

On MRI, it was possible to watch the stem cells migrating towards the diseased area of the brain. "Cells that go toward a certain position that needs to be rescued are the best indirect proof that they are live and viable," explains Dr. Cohen. "If they can migrate towards the target, they are alive and can read chemical signalling."

An ethically viable stem cell

This study is based on differentiated mesenchymal cells (MSC), which were discovered at Tel Aviv University. Bone marrow cells are transformed into NTFs-secreting stem cells, which can then be used to treat neurodegenerative diseases. This advance circumvents the ethical debate caused by the use of stem cells obtained from embryos.

Although there is a drawback to using this particular type of stem cell ― the higher degree of difficulty involved in rendering them "neuron-like" ― the benefits are numerous. "Bone marrow-derived MSCs bypass ethical and production complications," says Dr. Cohen, "and in the long run, the cells are less likely to be rejected because they come from the patients themselves. This means you don't need immunosuppressant therapy."

New Tool Gives Researchers a Glimpse of Biomolecules in Motion

Tue, 11 Aug 2009 01:50:23 GMT

The ability of biomolecules to flex and bend is important for the performance of many functions within living cells. However, researchers interested in how biomolecules such as amino acids and proteins function have long had to make inferences from a series of X-ray-like �still pictures� of pure crystalline samples. Now, using a new technique based on terahertz (THz) spectroscopy, scientists at the National Institute of Standards and Technology (NIST) have recently taken the first step toward revealing the hidden machinations of biomolecules in water.

With wavelengths that range from 1 millimeter to 25 micrometers, terahertz radiation falls between the infrared and microwave spectral regions. Researchers can determine how molecules are moving by passing terahertz radiation through a sample and measuring which wavelengths are absorbed. Unfortunately, room temperature water, the medium in which biological molecules typically are studied, absorbs nearly all of the terahertz radiation, limiting the utility of terahertz spectroscopy for probing biomolecular function.

To avoid the water problem, the NIST team needed to find a way to provide a simple but realistic environment for the biomolecules that contained the least amount of water possible. NIST researcher Ted Heilweil, National Research Council postdoctoral fellow Catherine Cooksey and NIST Summer Undergraduate Research Fellow Ben Greer from Carnegie Mellon University found their solution in the form of nanoscale droplets made of soap-like molecules called micelles.

Using the micelles as tiny test tubes, the team filled the hollow molecules with a small sample of water and the amino acid L-proline, a protein building block. Measurements validated their hypothesis that the micelles would provide an aqueous environment that allows the amino acid to flex and bend while limiting the absorption of the terahertz radiation by water. The terahertz measurements on this simple biomolecule compared well with expectations from other studies, further validating the technique.

According to Heilweil, this study is an important first step toward using terahertz radiation for studying biomolecules. More ambitious measurements on larger molecules such as small peptides, proteins, and DNA fragments will be more challenging, but he says it may be possible in the near future.

'Organic' May Not Mean Healthier

Thu, 30 Jul 2009 22:17:43 GMT

Food that beckons from the organic aisles of grocery stores may not be any better for you than what lines the rest of supermarket shelves.

According to a British review of studies done over the past 50 years, organic and conventionally produced foods have about the same nutrient content, suggesting that neither is better in terms of health benefits.

"We did not find any important differences in nutrient content between organically and conventionally produced foods," said study author Alan Dangour, a registered public health nutritionist with the London School of Hygiene and Tropical Medicine.

Nonetheless, the researchers noted, organic foods continue to grow in popularity. In the United Kingdom, the market share for organic foods increased 22 percent from 2005 to 2007, they said.

Likewise, the market for organic foods in the United States has grown at about a 20 percent rate each year since 1990, reaching $13.8 billion in consumer sales in 2005, according to the Organic Trade Association. That represents 2.5 percent of total food sales in the country, the trade group noted.

"As a registered dietitian, it is good to see that a systematic review of the literature supports what has long been believed -- that the nutritional content of traditionally grown foods and organic foods are comparable," said Connie Diekman, director of university nutrition at Washington University in St. Louis and past president of the American Dietetic Association. "This report provides confirmation for consumers that if they choose conventionally grown foods or organic foods they will be meeting their nutritional needs."

The review zeroed in on 162 studies that dealt with the nutrient content of foods. Only 55 were of what the researchers considered to be "satisfactory quality" -- a strong indicator that, overall, the science on the subject is not up to snuff.

They found no noted differences between conventional and organic crops with regard to vitamin C, magnesium, calcium, potassium, zinc and copper content. Organic crops did have higher levels of phosphorus, and conventionally produced crops had higher levels of nitrogen.

The Lonely Life of a Lighthouse Keeper

Sat, 27 Jun 2009 02:04:19 GMT

Keeping the lighthouse in working condition was a twenty-four hour job. The light was lit only between sunset and sunrise, but there was work to do all day long. The head keeper and three assistants shared the load in four six-hour shifts.

Every evening, a half-hour before sunset, a keeper walked down the wooden stairs to light the oil lamp, the lighthouse's source of illumination. Once the lamp was lit, the keeper wound the clockwork mechanism, lifting a 170 pound weight, which was attached to the clockwork mechanism by a hemp rope, nine feet off the floor. The earth's gravity would then pull the weight, through a small trap door, to the ground level 17 feet below. The clockwork mechanism was built to provide resistance so that it would take two hours and twenty minutes for the weight to descend the 17 feet. And as the weight descended and the clockwork mechanism's gears spun, the Fresnel lens would turn so that the light appeared to flash every five seconds. In addition to winding the clockwork mechanism every two-hours and twenty minutes throughout the night, the keeper had to keep the lamp wicks trimmed so that the light would burn steadily and efficiently, thus the nickname "wickie."

Daytime duties for the keepers included cleaning the lens, polishing the brass, stoking the steam-powered fog signal and making necessary repairs. At the end of each shift, the keeper trudged back up the wooden staircase. Sometimes the winds were so strong that he had to crawl on his hands and knees to keep from being knocked down. The highest wind speed recorded at Point Reyes was 133 m.p.h., and 60 m.p.h. winds are common.

The hard work, wind, fog and isolation at Point Reyes made this an undesirable post. Even so, one keeper stayed for about twenty-four years, a testament to his devotion and love of Point Reyes!

Insect's Fast

Tue, 23 Jun 2009 21:39:13 GMT

The male deer bot fly is reputed to develop flying speeds of several hundred miles per hour, but this is probably an exaggeration. A tabanid fly, related to horse flies, has been clocked at 90 miles per hour. Hawk moths have been timed at 33.5 miles per hour. A dragonfly of the species Anax parthenope has been clocked at almost 18 miles per hour. Honeybees fly at about 7 miles per hour, and have to beat their wings 190 times per second to do it.

Insects with the fastest wing beat frequency are the no-see-ums, or very tiny midges, which beat their hairy wings 1,046 times per second. Male mosquitoes beat their wings 450 to 600 times per second. Cabbageworm butterflies beat their wings nine times per second.

Varieties of Orange

Mon, 22 Jun 2009 20:31:22 GMT

Persian orange

The Persian orange, grown widely in southern Europe after its introduction to Italy in the 11th century, was bitter. Sweet oranges brought to Europe in the 15th century from India by Portuguese traders, quickly displaced the bitter, and are now the most common variety of orange cultivated. The sweet orange will grow to different sizes and colours according to local conditions, most commonly with ten carpels, or segments, inside.

Some South East Indo-European tongues name orange after Portugal, which was formerly the main source of imports of sweet oranges. Examples are Bulgarian portokal, Greek portokali , Persian porteghal , and Romanian portocala. Also in South Italian dialects , orange is named portogallo or purtualle, literally "the Portuguese ones". Related names can also be found in other languages: Turkish Portakal, Arabic al-burtuqal, Amharic birtukan, and Georgian phortokhali.

Portuguese, Spanish, Arab, and Dutch sailors planted citrus trees along trade routes to prevent scurvy. On his second voyage in 1493, Christopher Columbus brought the seeds of oranges, lemons and citrons to Haiti and the Caribbean. They were introduced in Florida in 1513 by Spanish explorer Juan Ponce de Leon, and were introduced to Hawaii in 1792.

Navel orange

A single mutation in 1820 in an orchard of sweet oranges planted at a monastery in Brazil yielded the navel orange, also known as the Washington, Riverside, or Bahie navel. The mutation causes navel oranges to develop a second orange at the base of the original fruit, opposite the stem. The second orange develops as a conjoined twin in a set of smaller segments embedded within the peel of the larger orange. From the outside, it looks similar to the human navel.

Because the mutation left the fruit seedless and, therefore, sterile, the only means available to cultivate more of this new variety is to graft cuttings onto other varieties of citrus tree. Two such cuttings of the original tree were transplanted to Riverside, California in 1870, which eventually led to worldwide popularity.

Today, navel oranges continue to be produced via cutting and grafting. This does not allow for the usual selective breeding methodologies, and so not only do the navel oranges of today have exactly the same genetic makeup as the original tree, and are therefore clones; in a sense, all navel oranges can be considered to be the fruit of that single over-a-century-old tree. This is similar to the common yellow seedless banana, the Cavendish.

On rare occasions, however, further mutations can lead to new varieties.

Valencia orange

The Valencia or Murcia orange is one of the sweet oranges used for juice extraction. It is a late-season fruit, and therefore a popular variety when the navel oranges are out of season. For this reason, the orange was chosen to be the official mascot of the 1982 FIFA World Cup, which was held in Spain. The mascot was called "Naranjito" , and wore the colours of the Spanish soccer team uniform.

Blood orange

The blood orange has streaks of red in the fruit, and the juice is often a dark burgundy colour. The fruit has found a niche as an interesting ingredient variation on traditional Seville marmalade, with its striking red streaks and distinct flavour. The scarlet navel is a variety with the same dual-fruit mutation as the navel orange.

Hawker Siddeley

Fri, 19 Jun 2009 20:56:49 GMT

Hawker Siddeley, one of the largest and best-known companies in British aviation, got its start through a bankruptcy. The failed firm, Sopwith Aviation, had been very active during World War I and had built the famous Sopwith Camel fighter plane. Orders from the government dried up following the end of the war, in 1918, and Sopwith found itself struggling. Then the British treasury presented a very large bill for excess profits during the war. Unable to pay it, Sopwith responded by declaring that it was bankrupt. Its assets were taken over by a group of investors led by the test pilot Harry Hawker. His new firm, H. G. Hawker Engineering Company, opened for business late in 1920.

Hawker found work initially by building motorcycles and motorcars and by rebuilding used aircraft. However, company officials wanted to return to being full-time planebuilders. The Royal Air Force was placing orders for small numbers of new aircraft from a variety of British companies, which gave Hawker Engineering its opportunity. A brilliant chief designer, Sydney Camm, helped as well.

Under his leadership, Hawker scored a substantial success with a single-engine bomber, the Hart. Camm introduced a steel framework for light weight. The finished aircraft had an empty weight of only 2,530 pounds (1,148 kilograms), which gave it great speed. When the first Harts entered service in 1930, they had a top speed of 184 miles per hour (296 kilometers per hour), which was 30 miles per hour (48 kilometers per hour) faster than biplane fighters that tried to intercept.

The Hart remained in production through much of the 1930s, and gave rise to 17 variants. Because of its high speed, it was adapted for use as a fighter. Another version, fitted with pontoons, flew with aircraft carriers of the Royal Navy. More than 3,000 Harts were built, making this the most produced British airplane in the years before World War II.

Few other companies approached this success. Indeed, after 1930, the Great Depression placed many planebuilders under considerable financial stress. Officials of the British government responded by encouraging aviation leaders to reorganize their industry into fewer but stronger companies. Thomas Sopwith, chairman of Hawker, took the initiative by drawing on profits from sales of Harts as he raised capital of �2 million, some $10 million. He then bought up other firms: Gloster Aircraft, Armstrong Siddeley Motors, Armstrong Whitworth Aircraft, Air Service Training, and A. V. Roe. In 1935 he reorganized these holdings as the Hawker Siddeley Aircraft Company. These mergers placed those firms on a good financial footing, at a time when war was only a few years away.

Also during 1935, the rising threat of war with Germany led the Under-Secretary of State for Air, Sir Philip Sassoon, to announce a sharp increase in the purchase of warplanes. This change in policy took place at a time when aircraft design was changing dramatically. The best aircraft of the day, including the Hart, still were biplanes. However, by the mid-1930s the all-metal monoplane was in the forefront. Such aircraft were heavier than biplanes, but excellent streamlining made them considerably faster. At Hawker, Sydney Camm soon was ready with a new fighter: the Hurricane. It first flew in November 1935. In April 1936, the directors of Hawker placed it into production even before receiving a formal government order. It entered service in 1938 and showed a top speed of 325 miles per hour (523 kilometers per hour), nearly twice that of the Hart.

Then in April 1940, the dictator of Germany, Adolf Hitler, unleashed a powerful army that already had overrun Poland in less than a month. The Netherlands now fell in only five days. France surrendered in June. With complete victory in view, Hitler then ordered his generals to prepare to invade England. Only one military command stood in their way: the Royal Air Force.

The ensuing Battle of Britain succeeded in defending that nation, as Hitler called off his invasion. The Hawker Hurricane emerged as the outstanding fighter of this conflict. Hurricanes in service outnumbered all other British fighters combined, shooting down 55 percent of all enemy aircraft destroyed. The historian Francis Mason writes that the Hurricane showed superior "ability to withstand battle damage, ease of repair, better ability to operate from poor quality [airfields] and comparative ease of flight training. It also proved much simpler to fly at night."

The end of World War II led quickly to the Cold War, a prolonged confrontation with the Soviet Union. Jet engines now were the key to fighter design, and Sydney Camm took advantage of their power by developing the Hawker Hunter fighter-bomber. During an early flight in 1953, its test pilot set a world speed record of 728 miles per hour (1,172 kilometers per hour). Amid steady improvement, the Hunter was crafted in 12 versions, with some 2,000 of these aircraft being built by 1960. Faster fighters by then were available, but a Hunter could be refueled and rearmed in as little as five minutes. It found a particular role in attacking ground targets, for which it did not require supersonic speed. It became popular in the export market, with hundreds of Hunters remaining in service into the 1980s.

Even so, it was clear by the mid-1950s that modern aircraft were too costly for Britain to pursue on its own. Nor was there need for them; American warplanes were the world's best and could easily be purchased. In 1957 the British minister of defense, Duncan Sandys, issued a White Paper, a formal document that announced a new policy: Great Britain would build no new fighter aircraft for its Royal Air Force. The industry was free to build airliners, sell fighters overseas, and collaborate with the United States and with France. Even so, this policy brought a sharp cutback in the prospects for Britain's planebuilders.

They responded with a new wave of mergers. The engine-builders Armstrong Siddeley and Bristol Aero-Engines combined in 1959 to form Bristol Siddeley. Hawker Siddeley took over the big firm of De Havilland Aircraft in 1960. Vickers, English Electric, and Bristol Aircraft united to create British Aircraft Corporation, also in 1960. Rolls Royce, the nation's leading engine builder, merged with Bristol Siddeley in 1966.

At Hawker, innovation continued. Ralph Hooper, a senior manager, developed a strong interest in a new Bristol engine, the Pegasus, with nozzles that could swivel in any direction. Hooper saw that a fighter powered by such an engine could direct its thrust downward to take off and land vertically, to hover, to stop in midair, and to maneuver in flight with unprecedented agility. He built an experimental airplane, the P.1127, which first flew in 1960. This led to an operational fighter, the Harrier. It showed such promise that the British government reversed its White Paper policy and purchased Harriers for both the Royal Navy and Royal Air Force, with the first of them entering service in 1968. The U.S. Marines acquired their own Harriers. In addition, Hawker Siddeley formed a partnership with America's firm of McDonnell Douglas. This brought development of an advanced Harrier that could carry heavier loads.

The Harrier went to war in 1982, when Argentina seized the British-held Falkland Islands in the South Atlantic. Prime Minister Margaret Thatcher sent a naval force that included these fighters. They shot down 28 Argentine aircraft while losing none of their own in aerial combat. The British won the battle and took back the islands.

By then the firm of Hawker Siddeley no longer existed as such. An act of Parliament in 1977 had combined it with British Aircraft to form a single enormous company, British Aerospace. But old Thomas Sopwith�Sir Thomas, having been knighted in 1953�was still very much alive. He had been chairman first of Hawker and then of Hawker Siddeley since 1920. He died in 1989 at the age of 100 years, as the last pioneer from the early days of British aviation.

By - Joseph Letzelter

ABOUT THE GEORGIA AQUARIUM

Thu, 18 Jun 2009 20:55:23 GMT

The Georgia Aquarium in Atlanta, Georgia, is the world�s largest with more than eight million gallons of water and the largest collection of aquatic animals. The mission of the Georgia Aquarium is to be an entertaining, educational and scientific institution featuring exhibits and programs of the highest standards; offering engaging and exciting guest experiences promoting the conservation of aquatic biodiversity throughout the world. The Georgia Aquarium is an accredited member of the Association of Zoos and Aquariums and the Alliance of Marine Mammal Parks and Aquariums.

Cloning in Human

Wed, 17 Jun 2009 21:06:54 GMT

Human cloning is the creation of a genetically identical copy of a human being , human cell, or human tissue.

Although the possibility of cloning human beings has been the subject of speculation for much of the twentieth century, scientitists and policy makers began to take the prospect seriously in the 1960s. Nobel Prize winning geneticist Joshua Lederberg advocated for cloning and genetic engineering in a seminal article in the American Naturalist in 1966 and again, the following year, in the Washington Post. He sparked a debate with conservative bioethicist Leon Kass, who wrote at the time that "the programmed reproduction of man will, in fact, dehumanize him." Another Nobel Laureate, James Watson, publicized the potential and the perils of cloning in his Atlantic Monthly essay, "Moving Toward the Clonal Man", in 1971.

Human cloning also gained a foothold in popular culture, starting in the 1970s. Alvin Toffler's Future Shock, David Rorvik's In His Image: Toward Cloning of a Man, Woody Allen's film Sleeper and The Boys from Brazil all helped to make the public aware of the ethical issues surrounding human cloning.

Indian Space Programme

Tue, 16 Jun 2009 18:59:41 GMT

Despite being a developing economy with its attendant problems, India has effectively developed space technology and has applied it successfully for its rapid development and today is offering a variety of space services globally. During the formative decade of 1960s, space research was conducted by India mainly with the help of sounding rockets. The Indian Space Research Organisation (ISRO) was formed in 1969. Space research activities were provided additional fillip with the formation of the Space Commission and the Department of Space by the government of India in 1972. And, ISRO was brought under the Department of Space in the same year. In the history of the Indian space programme, 70s were the era of Experimentation during which experimental satellite programmes like Aryabhatta, Bhaskara, Rohini and Apple were conducted. The success of those programmes, led to era of operationalisation in 80s during which operational satellite programmes like INSAT and IRS came into being. Today, INSAT and IRS are the major programmes of ISRO.

For launching its spacecraft indigenously, India is having a robust launch vehicle programme, which has matured to the state of offering launch services to the outside world. Antrix, the commercial arm of the Department of Space, is marketing India�s space services globally. Fruitful co-operation with other space faring nations, international bodies and the developing world is one of the main characteristics of India's space programme.

The most significant milestone of the Indian Space Programme during the year 2005-2006 was the successful launch of PSLV-C6. On 5 May 2005, the ninth flight of Polar Satellite Launch Vehicle (PSLV-C6) from Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota successfully placed two satellites - the 1560 kg CARTOSTAR-1 and 42 kg HAMSAT - into a predetermined polar Sun Synchronous Orbit (SSO). Coming after seven launch successes in a row, the success of PSLV-C6 further demonstrated the reliability of PSLV and its capability to place payloads weighing up to 1600 kg satellites into a 600 km high polar SSO.

The successful launch of INSAT-4A, the heaviest and most powerful satellite built by India so far; on 22 December 2005 was the other major event of the year 2005-06. INSAT-4A is capable of providing Direct-To-Home (DTH) television broadcasting services.

Besides, the setting up of the second cluster of nine Village Resource Centres (VRCs) was an important ongoing initiative of the Department of Space during the year. VRC concept integrates the capabilities of communications and earth observation satellites to provide a variety of information emanating from space systems and other IT tools to address the changing and critical needs of rural communities.