Δευτέρα, 2 Ιουνίου 2014

ScienceDaily: Latest Science News

ScienceDaily: Latest Science News


Leptin also influences brain cells that control appetite, researchers find

Posted: 01 Jun 2014 12:09 PM PDT

Twenty years after the hormone leptin was found to regulate metabolism, appetite, and weight through brain cells called neurons, researchers have found that the hormone also acts on other types of cells to control appetite. Leptin, a naturally occurring hormone, is known for its hunger-blocking effect on the hypothalamus, a region in the brain. Food intake is influenced by signals that travel from the body to the brain. Leptin is one of the molecules that signal the brain to modulate food intake.

Exciton detected in metal for first time: Microscopic quantum mechanical description of how light excites electrons in metals

Posted: 01 Jun 2014 12:09 PM PDT

Scientists have detected a fundamental particle of light-matter interaction in metals, the exciton for the first time. Humankind has used reflection of light from a metal mirror on a daily basis for millennia, but the quantum mechanical magic behind this familiar phenomenon is only now being uncovered.

Subtle change in DNA, protein levels determines blond or brunette tresses, study finds

Posted: 01 Jun 2014 12:09 PM PDT

A molecule critical to stem cell function plays a major role in determining human hair color, according to a new study. The study describes for the first time the molecular basis for one of our most noticeable traits. It also outlines how tiny DNA changes can reverberate through our genome in ways that may affect evolution, migration and even human history.

Graphene's multi-colored butterflies

Posted: 01 Jun 2014 12:09 PM PDT

Combining black and white graphene can change the electronic properties of the one-atom thick materials, researchers have found. One of the major challenges for using graphene in electronics applications is the absence of a band gap, which basically means that graphene's electrical conductivity cannot be switched off completely. Whatever researchers tried to do with the material so far, it remained highly electrically conductive.

Tracking animals on videos: Software able to identify and track a specific individual within a group

Posted: 01 Jun 2014 12:08 PM PDT

It is easy to follow the route traced by an animal by using video recordings of the animal. The problem arises when the behavior of two or more individuals is studied, as animals often cross or interact with other members of the group and wrong assignments of identity for each animal occur. These faults make virtually impossible to identify an individual after several minutes of video.

'Quadrapeutics' works in preclinical study of hard-to-treat tumors: Animal tests show technology effective against aggressive cancer

Posted: 01 Jun 2014 12:08 PM PDT

The first preclinical tests for a novel anti-cancer technology called 'quadrapeutics' that converts current clinical treatments to instantaneously detect and kill only cancer cells have been successful. Quadrapeutics combines clinically available drugs, colloidal gold, pulsed lasers and radiation in a novel and safe micro-treatment that improved standard therapy by 17-fold against aggressive, drug-resistant tumors.

New genetic cause of male reproductive birth defects identified

Posted: 01 Jun 2014 12:08 PM PDT

A previously unrecognized genetic cause for two types of birth defects found in newborn boys has described in a report. Cryptorchidism is characterized by the failure of descent of one or both testes into the scrotum during fetal development. In the adult man, the testes produce sperm and the male hormone, testosterone. Hypospadias is the abnormal placement of the opening of the urethra on the penis. Both birth defects are usually surgically repaired during infancy.

Smokers with gene defect have one in four chance of developing lung cancer

Posted: 01 Jun 2014 12:08 PM PDT

Around a quarter of smokers who carry a defect in the BRCA2 gene will develop lung cancer at some point in their lifetime, a large-scale, international study reveals. Scientists announce a previously unknown link between lung cancer and a particular BRCA2 defect, occurring in around 2 per cent of the population.

Drug combination extends survival by more than a year in metastatic prostate cancer

Posted: 01 Jun 2014 12:06 PM PDT

Men with newly diagnosed metastatic, hormone-sensitive prostate cancer lived more than a year longer when they received a chemotherapy drug as initial treatment instead of waiting to for the disease to become resistant to hormone-blockers, report scientists. The dramatic results in a multi-center phase III trial should change the way physicians have routinely treated such patients since the 1950s, they said.

Hormone that controls supply of iron in red blood cell production discovered by researchers

Posted: 01 Jun 2014 12:06 PM PDT

A new hormone called erythroferrone, which regulates the iron supply needed for red blood-cell production, has been discovered by researchers. Iron is an essential functional component of hemoglobin. Using a mouse model, researchers found that erythroferrone is made by red blood-cell progenitors in the bone marrow in order to match iron supply with the demands of red blood-cell production. Erythroferrone is greatly increased when red blood-cell production is stimulated, such as after bleeding or in response to anemia.

Amplification of cosmic magnetic fields replicated

Posted: 01 Jun 2014 12:06 PM PDT

Astrophysicists have established that cosmic turbulence could have amplified magnetic fields to the strengths observed in interstellar space. "Magnetic fields are ubiquitous in the universe," said one of the researchers. "We're pretty sure that the fields didn't exist at the beginning, at the Big Bang. So there's this fundamental question: how did magnetic fields arise?"

Paired enzyme action in yeast reveals backup system for DNA repair

Posted: 01 Jun 2014 12:06 PM PDT

The combined action of two enzymes, Srs2 and Exo1, prevents and repairs common genetic mutations in growing yeast cells, according to a new study. Because such mechanisms are generally conserved throughout evolution, at least in part, researchers say the findings suggest that a similar DNA repair kit may exist in humans and could serve as a target for controlling some cancers and treating a rare, enzyme-linked genetic disorder called Aicardi-Goutieres syndrome.

Newly identified brain cancer mutation will aid drug development

Posted: 01 Jun 2014 12:06 PM PDT

New genetic insights into a rare and deadly form of childhood and young adult brain cancer called brainstem glioma has been identified by an international team of researchers. The researchers identified a genetic mutation in the tumor cells that plays a role in both the growth and the death of a cell. Additionally, the mutation to the newly identified gene may also contribute to the tumor's resistance to radiation.

How to erase a memory –- and restore it: Researchers reactivate memories in rats

Posted: 01 Jun 2014 12:06 PM PDT

Researchers have erased and reactivated memories in rats, profoundly altering the animals' reaction to past events. The study is the first to show the ability to selectively remove a memory and predictably reactivate it by stimulating nerves in the brain at frequencies that are known to weaken and strengthen the connections between nerve cells, called synapses.

Escalating care in cormorbid elderly: Where do we stop?

Posted: 31 May 2014 06:35 PM PDT

A patient's age should not in itself be considered an ethically relevant criterion for deciding 'where to stop' providing care, an ethical expert says. He says: "If societies do wish to pursue such 'ageist' policies then they should do so only do so after widespread consultation and the enactment of democratically established laws according to which patients condemned to be denied life-prolonging therapies on grounds of age alone should have a legal right of appeal."

Patients admitted to hospital at weekends have higher mortality: Study of 55 million people adds further evidence

Posted: 31 May 2014 06:35 PM PDT

A systematic review and meta-analysis of hospital data worldwide adds further evidence that patients admitted to hospital at weekends have higher mortality than those admitted on weekdays. The analysis included 72 studies from various world regions, covering 55,053,719 participants. The authors found that weekend admission was associated with increased morality of between 15% and 17% depending on the statistical technique used.

Risk of death highest following surgery in afternoons, at weekends, and in February

Posted: 31 May 2014 06:35 PM PDT

On weekends, in the afternoons and in February are the times when the risk of death following surgery is the highest, research demonstrates. Hospital mortality is subject to day-night, weekly and seasonal variability. However, a cyclic influence on hospital mortality has not been shown in patients after surgery. In this study, the researchers investigated the daily, weekly, and seasonal variability of hospital mortality in patients after surgery.

Poor coverage of specific gene sets in exome sequencing gives cause for concern

Posted: 31 May 2014 06:35 PM PDT

Researchers have analyzed 44 exome datasets from four different testing kits and shown that they missed a high proportion of clinically relevant regions. At least one gene in each exome method was missing more than 40 percent of disease-causing genetic variants, and the worst-performing method missed more than 90 percent of such variants. This means that there is a  substantial possibility of reporting false negative results, they say.

Responses with crizotinib in MET-amplified lung cancer show new targetable form of disease

Posted: 31 May 2014 12:49 PM PDT

In 2011, the drug crizotinib earned accelerated approval by the US FDA to target the subset of advanced non-small cell lung cancers caused by rearrangements of the anaplastic lymphoma kinase (ALK) gene. The drug also has shown dramatic responses in patients whose lung cancers harbored a different molecular abnormality, namely ROS1 gene rearrangements.

Results in Phase I trial targeting cancer stem cells

Posted: 31 May 2014 12:48 PM PDT

Results of a Phase I trial of OMP-54F28 (FZD8-Fc), an investigational drug candidate targeting cancer stem cells (CSCs) have been released. The drug was generally well tolerated, and several of the 26 patients with advanced solid tumors experienced stable disease for greater than six months. Three trials are now open in combinations with standard therapy for pancreatic, ovarian and liver cancers.

One step closer to a breath test for lung cancer

Posted: 31 May 2014 12:48 PM PDT

A test of organic compounds in exhaled breath can not only distinguish patients with lung cancer from patients with chronic obstructive pulmonary disease (COPD), but can also define the stage of any cancer present, new research shows. The device requires blowing up a balloon, which is then attached to an extremely sensitive gold nanoparticle sensor. The particles in the sensor trap and then help to analyze volatile organic compounds in the exhaled breath.

Patients with metastatic colon cancer respond to new combination therapy

Posted: 31 May 2014 10:23 AM PDT

In an aggressive disease known for poor response rates, researchers found patients with advanced colorectal cancer responded well to a combination therapy of the drugs vermurafenib, cetuximab and irinotecan. "What's promising is the fact that we're seeing these high response rates in early studies which suggests this could become a new standard of care down the line," one researcher said. "There's clearly some kind of synergistic activity with the combination."

Level of addiction to tobacco measured by new virtual platform

Posted: 31 May 2014 06:07 AM PDT

In Mexico, 21.7 percent of the population smokes, which is associated with 95 percent of (lung cancer cases and the development of 29 more different conditions. A citizen science project titled "Are you smoking away?" is part of the venture "Science that Breathes" that makes available a tool that leads to answer a series of questions about the perceptions that people have about smoking.

Prevalence of new genetic driver in lung cancer shown in study

Posted: 31 May 2014 06:06 AM PDT

A line has been drawn from mutation of the gene NTRK1, to its role as an oncogene in non-small cell lung cancer, to treatment that targets this mutation. "Everything we know about lung cancer points to the idea that when we find one of these genetic drivers and can target it with a drug, patients will respond and tend to have a good amount of time on drug before it becomes ineffective. Obviously we can't guarantee the effectiveness of targeting the NTRK1 mutation at this point, but everything we know about these kinds of genes makes us extremely hopeful," says one researcher.

There may be multiple paths to fuel reduction in the wildland-urban interface

Posted: 30 May 2014 04:05 PM PDT

Conservative fuel treatments designed to reduce fire severity while still providing forest cover and wildlife habitat worked equally as well as more intensive treatments in allowing for the protection of homes during the 2011 Wallow Fire, a study has found. The distance into the treated area where fire severity was reduced varied, however, between these different thinning approaches where fuels were reduced.

'Often and early' gives children a taste for vegetables

Posted: 30 May 2014 04:05 PM PDT

Exposing infants to a new vegetable early in life encourages them to eat more of it compared to offering novel vegetables to older children, new research suggests. The researchers also found that even fussy eaters are able to eat a bit more of a new vegetable each time they are offered it.

New genetic sequencing methods mean quicker, cheaper, equally accurate embryo screening

Posted: 30 May 2014 04:04 PM PDT

Results from the first study of the clinical application of next generation DNA sequencing (NGS) in screening embryos for genetic disease prior to implantation in patients undergoing in-vitro fertilization treatments show that it is an effective reliable method of selecting the best embryos to transfer. Research has shown that NGS, a high throughput sequencing method, has the potential to revolutionize pre-implantation genetic screening (PGS).

Osteoporosis: Genetic researchers take major step towards better diagnosis, treatment

Posted: 30 May 2014 04:04 PM PDT

A new target that may be critical for the treatment of osteoporosis, a disease which affects about 25% of post-menopausal women, has been discovered by a group of researchers. New studies in zebrafish and mice have shown that injection of human plastin 3 (PLS3) or related proteins in zebrafish where PLS3 action has been suppressed can replace its loss and repair the bone development anomalies associated with this deficiency.

Genetically identical ants help unlock the secrets of larval fate

Posted: 30 May 2014 01:10 PM PDT

A young animal's genes are not the only genes that determine its fate. The genetic identity of its caretakers matters too. Researchers suspect the interaction between the two can sway the fate of the young animal, but this complex dynamic is difficult to pin down in lab experiments. However, social insect researchers have found a solution and are developing a species of small raider ants as a model organism in order to ask questions about the relationships between genes, social behavior and evolution.

Stem cell progeny tell their parents when to turn on

Posted: 30 May 2014 01:07 PM PDT

Stem cells switch off and on, sometimes dividing to produce progeny cells and sometimes resting. But scientists don't fully understand what causes the cells to toggle between active and quiet states. New research focused on stem cells in the hair follicle to determine what switches them on. The researchers found cells produced by the stem cells, progeny known at Transit-Amplifying Cells or TACs, emit a signal that tells quiet hair follicle stem cells to become active.

New method of wormlike motion lets gels wiggle through water

Posted: 30 May 2014 01:03 PM PDT

A special hydrogel substance has been developed that can be equipped to detect bacteria, carry cargo and deliver medicine. A researcher used a worm's contracting and expanding motion to provide a way for gels to swim in water. He explains, "Using a hand-held laser, we were able to selectively and quickly shrink the hydrogel (a hydrophilic polymer gel comprised mostly of water) in desired areas. By inducing a shrinking/swelling cycle down the length of a hydrogel, we were able to successfully mimic peristaltic, or earthworm-inspired, locomotion in water."

Quality of preschools depends on where you live

Posted: 30 May 2014 12:59 PM PDT

Private and voluntary (not-for-profit) nurseries and preschools catering for disadvantaged areas and children are lower quality than those serving more advantaged areas and children, according to research. The 'quality gap' is widest in relation to how they support children's language skills. This finding is particularly significant given that disadvantaged children at the age of five are already almost a year behind those from wealthier backgrounds in terms of their vocabulary, and the gap increases as they move through school.

Quality, not quantity, counts most in exercise, diet

Posted: 30 May 2014 12:41 PM PDT

The clear benefits of a multi-dimensional exercise regimen that includes resistance exercise, interval sprint exercise, stretching (including yoga or pilates), endurance exercise, and moderate amounts of protein consumed regularly throughout the day have been demonstrated and reported by exercise scientists. If your goal is to lose weight and maintain optimal health and fitness, the quality of your exercise and diet regimen matters more than the quantity, they say.

Increasing sensitivity of HPV detection in cancer with new test

Posted: 30 May 2014 12:41 PM PDT

Results from a pilot study demonstrating the utility of a new cancer panel to detect previously undetected viral and cancer mutations have been released by researchers. The panel identified human papilloma virus (HPV) sequences undetected by conventional laboratory tests as well as new unreported HPV mutations. It is estimated that each year there are approximately 30,000 cases of HPV-associated cancers in the US.

Coaxing iPS cells to become more specialized prior to transplantation cuts rejection risk

Posted: 30 May 2014 11:25 AM PDT

Coaxing iPS cells in the laboratory to become more-specialized progeny cells (a cellular process called differentiation) before transplantation into mice allows them to be tolerated by the body's immune system, research has found. "This study shows that undifferentiated iPS cells are rejected by the immune system upon transplantation in the same recipient, but that fully differentiating these cells allows for acceptance and tolerance by the immune system without the need for immunosuppression," said a researcher.

Vaccination opt out is a cop out that literally is making people sick, says infectious disease leader

Posted: 30 May 2014 11:24 AM PDT

Measles have reached a 20-year high in the United States and the cause lies squarely with those who deliberately refuse to be vaccinated. Eighty-five percent of the unvaccinated U.S. residents who contracted measles cited religious, philosophical or personal reasons for not getting immunized. "Religious, philosophical or personal reasons are not medical reasons for not getting vaccinated," says one infectious disease expert.

Stopping statins may benefit terminally ill patients

Posted: 30 May 2014 11:24 AM PDT

People in the late stages of cancer and other terminal illnesses are not only unharmed by discontinuing statins for cholesterol management, they may benefit, according to a study. The finding addresses a thorny question in treating people with life-limiting illnesses: When, if ever, is it appropriate to discontinue medications prescribed for other conditions that will likely not lead to their death?

Women with metastatic breast cancer can safely receive bisphosphonates less frequently, without compromising care

Posted: 30 May 2014 11:24 AM PDT

Women with metastatic breast cancer to the bone may be able to receive bisphosphonates, the bone-targeting class of drugs like zoledronic acid, less often after the first year of monthly administration. With that practice change, women may also reduce their risk of serious side effects, according to a study.

Genetic profile predicts which bladder cancer patients will benefit from early chemotherapy

Posted: 30 May 2014 10:33 AM PDT

Three genetic changes can predict whether a patient will benefit from chemotherapy before surgery to remove bladder cancer, according to new findings. These results suggest that doctors may one day sequence patients' tumors for the presence of these three mutations, to determine who will likely benefit most from chemotherapy before surgery, said one investigator.

Hepatitis C reactivation doesn't worsen survival for HIV+ patients diagnosed with lymphoma

Posted: 30 May 2014 10:32 AM PDT

Hepatitis C reactivation doesn't worsen survival for HIV+ patients diagnosed with lymphoma, research shows. More than a quarter of HIV+ patients are also infected with the Hepatitis C virus (HCV), which may complicate treatment and care decisions after a cancer diagnosis. The specifics of those complications haven't been well-researched before this study.

Urbanization, future heat-related mortality linked

Posted: 30 May 2014 10:32 AM PDT

Phoenix stands at a parched crossroads. Global scale climate change is forecast to bring hotter summers and more extreme heat to the Valley, but regional urbanization also will impact temperatures experienced by residents. So how should Phoenix grow knowing that such growth could cause temperatures to increase in the future and bring added health risks? Should the city deploy mitigating technologies to help fight summer's heat? Would adopting a low-growth strategy reduce the adverse health consequences of hot weather?

Compounds in saliva, common body proteins may fend off DNA-damaging chemicals in tea, coffee and liquid smoke

Posted: 30 May 2014 10:31 AM PDT

A compound in saliva, along with common proteins in blood and muscle, may protect human cells from powerful toxins in tea, coffee and liquid smoke flavoring, according to results of a new study. The findings suggest that the presence of these defenses could help explain why PLPs are not crippling cells and causing illness as would be expected from their toxic punch and widespread use, the researchers say.

Rush a light wave and you'll break its data, say scientists

Posted: 30 May 2014 09:44 AM PDT

Quantum information can't break the cosmic speed limit, according to researchers. The scientists have shown how attempts to 'push' part of a light beam past the speed of light results in the loss of the quantum data the light carries. The results could clarify how noise might limit the transfer of information in quantum computers.

Novel laser system mimics sunlight to test solar cell efficiency

Posted: 30 May 2014 09:44 AM PDT

A laser-based instrument that generates artificial sunlight to help test solar cell properties, and find ways to boost their efficiency, has been developed by researchers. The novel system simulates sunlight well across a broad spectrum of visible to infrared light. More flexible than conventional solar simulators such as xenon arc-lamps or light-emitting diodes, the laser instrument can be focused down to a small beam spot -- with resolution approaching the theoretical limit -- and shaped to match any desired spectral profile.

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