الثلاثاء، 25 فبراير 2014

ScienceDaily: Top News

ScienceDaily: Top News


New insights into origin of birds focuses on key characteristics that preceded flight: Body size, forelimb length

Posted: 23 Feb 2014 06:51 PM PST

The key characteristics of birds which allow them to fly -- their wings and their small size -- arose much earlier than previously thought, according to new research that examined closely the Paraves, the first birds, and their closest dinosaurian relatives which lived 160 to 120 million years ago. Researchers investigated the rates of evolution of the two key characteristics that preceded flight: body size and forelimb length. In order to fly, hulking meat-eating dinosaurs had to shrink in size and grow much longer arms to support their feathered wings.

Mysterious polio-like illness found in five California children

Posted: 23 Feb 2014 06:51 PM PST

Researchers have identified a polio-like syndrome in a cluster of children from California over a one-year period, according to a case report released. Polio is a contagious disease that sometimes caused paralysis. The United States experienced a polio epidemic in the 1950s, until a vaccine was introduced. The five children experienced paralysis of one or more arms or legs that came on suddenly and reached the height of its severity within two days of onset. Three of the children had a respiratory illness before the symptoms began. All of the children had been previously vaccinated against poliovirus. The children were treated but their symptoms did not improve and they still had poor limb function after six months.

Nanoparticles target anti-inflammatory drugs where needed

Posted: 23 Feb 2014 10:17 AM PST

A system for precisely delivering anti-inflammatory drugs to immune cells gone out of control, has been developed that spares the well-behaved counterpart cells in the body. The system uses nanoparticles made of tiny bits of protein designed to bind to unique receptors found only on neutrophils, a type of immune cell engaged in detrimental acute and chronic inflammatory responses. In chronic inflammation, neutrophils can pile up at the site of injury, sticking to the blood vessel walls and to each other and contributing to tissue damage.

Climate change won't reduce deaths in winter, British study concludes

Posted: 23 Feb 2014 10:17 AM PST

Climate change is unlikely to reduce the United Kingdom's excess winter death rate, which was a previous hypothesis. The study debunks the widely held view that warmer winters will cut the number of deaths normally seen at the coldest time of year. The study found that from 1951 to 1971, the number of cold winter days was strongly linked to death rates, while from 1971 to 1991, both the number of cold days and flu activity were responsible for increased death rates. However, their analysis showed that from 1991 to 2011, flu activity alone was the main cause in year to year variation in winter mortality.

Stream of stars in Andromeda satellite galaxy shows cosmic collision

Posted: 23 Feb 2014 10:17 AM PST

The Andromeda Galaxy is surrounded by a swarm of small satellite galaxies. Researchers have detected a stream of stars in one of the Andromeda Galaxy's outer satellite galaxies, a dwarf galaxy called Andromeda II. This galaxy is very small -- less than one percent of the Milky Way. The movement of the stars tells us that what we are observing is the remnant of a merger between two dwarf galaxies. Mergers between galaxies of such low mass has not been observed before.

Lymphoid cells discovered in human spleen, essential for production of antibodies

Posted: 23 Feb 2014 10:17 AM PST

Researchers have discovered the presence of a novel subtype of innate lymphoid cells in human spleen essential for the production of antibodies. This discovery clears the path to the identification of novel strategies to develop more efficient vaccines against encapsulated bacteria, considered highly virulent. This research involved in vitro studies with isolated cells from human spleen samples and in vivo studies performed with different mice models.

malaria parasite transmission to mosquitos: Protein discovered as essential

Posted: 23 Feb 2014 10:17 AM PST

Scientists studying the sexual transformation of the malaria parasite have solved a long-standing mystery in parasite biology. Two research teams have independently discovered that a single protein acts as the master genetic switch that triggers the development of male and female sexual forms of the malaria parasite. The research also gives important clues for identifying the underlying mechanisms that control this developmental fate, determining whether or not a malaria parasite will be able to transmit the disease. The discovery has important implications for human health.

Skin cells transformed into functioning liver cells in mouse study

Posted: 23 Feb 2014 10:17 AM PST

An important breakthrough has been made that could affect patients waiting for liver transplants. Scientists have discovered a way to transform skin cells into mature, fully functioning liver cells that flourish on their own, even after being transplanted into laboratory animals modified to mimic liver failure. In previous studies on liver-cell reprogramming, scientists had difficulty getting stem cell-derived liver cells to survive once being transplanted into existing liver tissue. But this team figured out a way to solve this problem, and have revealed a new cellular reprogramming method that transforms human skin cells into liver cells that are virtually indistinguishable from the cells that make up native liver tissue.

'Microbial Pompeii:' 1,000 year old plaque preserves bacteria, microscopic particles of food on skeleton teeth, creating mineral tomb for microbiomes

Posted: 23 Feb 2014 10:16 AM PST

A 'microbial Pompeii' has been discovered, preserved on the teeth of skeletons around 1,000 years old. The research team discovered that the ancient human oral cavity carries numerous opportunistic pathogens and that periodontal disease is caused by the same bacteria today as in the past, despite major changes in human diet and hygiene. "The study of ancient microbiomes helps us understand the evolutionary history of human health and disease," says a senior author of the study. "It informs modern medicine."

Acupuncture holds promise for treating inflammatory disease

Posted: 23 Feb 2014 10:16 AM PST

Electroacupuncture may reduce inflammation that causes sepsis death, a recent study has shown. This research shows physical evidence of acupuncture's value beyond any that has been demonstrated before, and also shows potential benefits not just for sepsis, but for treating other inflammatory diseases such as rheumatoid arthritis, osteoarthritis and Crohn's disease. While investigating acupuncture mechanisms, the researchers also have determined that fenoldopam, a dopamine receptor agonist, also shows promise as a pharmaceutical sepsis treatment.

Brain region essential for social memory identified

Posted: 23 Feb 2014 10:16 AM PST

A small region of the hippocampus known as CA2 is essential for social memory, the ability of an animal to recognize another of the same species, a new study concludes. In humans, the importance of the hippocampus for social memory was famously illustrated by the case of Henry Molaison, who had much of his hippocampus removed by surgeons in 1953 in an attempt to cure severe epilepsy. Molaison was subsequently unable to form new memories of people. A better grasp of the function of CA2 could prove useful in understanding and treating disorders characterized by altered social behaviors, such as autism, schizophrenia, and bipolar disorder.

Oldest bit of crust firms up idea of cool early earth

Posted: 23 Feb 2014 10:16 AM PST

With the help of a tiny fragment of zircon extracted from a remote rock outcrop in Australia, the picture of how our planet became habitable to life about 4.4 billion years ago is coming into sharper focus. New research reveals data that confirms that Earth's crust first formed just 160 million years after the formation of our solar system. It also confirms that the timeframe that the planet was a fiery ball covered in a magma ocean came earlier, and that in order to become habitable, Earth cooled and formed its crust during the first geologic eon of the planet. The research may help scientists to understand how other habitable planets may form.

The Hubble showdown: Starbursts versus monsters

Posted: 23 Feb 2014 08:25 AM PST

The dominating figure in the middle of this new Hubble image is a galaxy known as MCG-03-04-014. It belongs to a class of galaxies called luminous infrared galaxies -- galaxies that are incredibly bright in the infrared part of the spectrum.

Reducing HIV transmission among drug injectors lowers AIDS mortality in heterosexuals

Posted: 21 Feb 2014 09:57 AM PST

A recent study sheds light on the pathways connecting HIV epidemics in different populations, concluding that programs for people who use drugs -- like syringe exchange, HIV counseling and testing, and drug abuse treatment -- are associated with subsequent lower rates of AIDS incidence and death among heterosexuals. The study also highlights a link between racial/ethnic residential segregation and rates of AIDS incidence and mortality among heterosexuals and points to evidence pairing social causations like income inequality with mortality.

Degradation of viral DNA in cell nucleus opening up new treatment for hepatitis B

Posted: 21 Feb 2014 07:39 AM PST

Viruses such as HBV can persist by depositing their genetic information (DNA) in the cell nucleus, where the DNA is normally not degraded. This prevents antiviral drugs from eliminating these viruses. But a newly discovered mechanism could make this possible without damaging the infected cell in the liver, possibly opening up new therapeutic possibilities.

Lower cancer incidence rate in patients with central nervous system disease explained

Posted: 20 Feb 2014 04:35 PM PST

Epidemiological studies demonstrate that diseases of the central nervous system such as Alzheimer, Parkinson and schizophrenia protect against cancer. The most remarkable example is Alzheimer's disease, which can reduce the risk of suffering from cancer by up to 50%. Various theories have been put forward in an attempt to explain this relationship between diseases at a first glance seem to be so different from the pharmacological, genetic and environmental perspectives. This week, the first evidence of a molecular relationship between cancer and central nervous system diseases has been published, identifying almost a hundred genes that could explain this relationship.

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