Dust and debris parade in an extremely misshapen ring around the young star HD 15115.

A stronomers using the Hubble Space Telescope (HST) and W.M. Keck Observatory have found a lopsided debris disk around young star HD 15115. As seen from Earth, the edge-on disk resembles a needle sticking out from the star.
Astronomers think the disk’s odd, imbalanced look is caused by dust following a highly elliptical orbit about the star. The lopsided disk may have been caused by the gravity of planets sweeping up debris in the disk, or by the gravity of a nearby star.
The observations were made by Paul Kalas, James Graham, and Michael P. Fitzgerald, all from the University of California at Berkeley, Astronomy.com reported.
“The lopsided disk presents a host of new challenges for theorists,“ said Kalas.
Debris disks are produced by dust from collisions among protoplanetary bodies, building blocks of planets. These dusty disks can be affected by planets near the star, much as Jupiter’s gravity affects asteroids in the asteroid belt.
This discovery is consistent with models for planetary upheavals in our own solar system, where Neptune may have originally formed between Saturn and Uranus. Neptune was eventually kicked out to its present location by a gravitational dance between Saturn and Jupiter before their orbits stabilized. “Therefore, we speculate that if such a planetary upheaval were occurring around HD 15115 at the present time, it could explain the highly asymmetric disk,“ Kalas said.
This might happen through a powerful gravitational interaction between planets that kicks one or more planets into highly elliptical orbits, or even ejects them into interstellar space. When the planet’s orbit becomes elliptical through a violent upheaval, the rest of the disk can be disturbed into an elliptical shape, according to Kalas.
Kalas also is studying whether the gravity of a star known as HIP 12545, located about 10 light-years from HD 15115, may have created the disk’s lopsided shape due to a close encounter in the past.
Dusty disks are known to exist around at least 100 stars, but because of the difficulty in observing material within the glare of a star, less than a dozen have been studied closely.
The dusty disk around HD 15115 was first inferred by observations at infrared wavelengths in 2000--its existence was confirmed in 2006 when HST resolved the disk in reflected light for the first time. The disk was investigated further using Keck adaptive optics in 2006 and 2007.

HIV-infected cell

An international collaboration between European, Australian and American researchers has unveiled some of the genetic mysteries explaining why some people naturally keep HIV levels almost undetectable, whereas others quickly lose control of the infection. Foundation irsiCaixa from the Hospital Germans Trias i Pujol, and Hospital Clinic are the two Catalan centers in this study.
This international collaboration has been the largest ever to have taken place in a large scale study on genetic differences between patients infected by HIV, and is the first study of this kind in the field of infectious disease. Catalan participants have been coordinated by Javier Martonez-Picado, ICREA research professor in the Foundation irsiCaixa of Hospital Germans Trias i Pujol, and Josep M. Miro, consultant of the Unit of Infectious Diseases and AIDS of Hospital Clinic-IDIBAPS of Barcelona, and had the collaboration of Hospital de la Santa Creu i Sant Pau, and Hospital Mutua de Terrassa.
Research has been conducted with the latest genomics and bioinformatics technologies, analyzing 550,000 variations of the complete human genome in 486 patients, mostly European, preselected from 30,000 potential candidates, Science Daily reported.
These variations, known as simple nucleotide polymorphisms (SNPs), are single variations affecting only one nucleotide or base of the genomic sequence. Despite humans sharing 99.9% of the genome sequence, there are still 3 million genetic variations Ðwhich make us different from one anotherÐ 90% of which are due to SNPs. Hence, a good knowledge of these variations is highly valuable for the determination of the progression of AIDS.
During the present study, obtained genetic data was compared to blood virus load in patients during the first two years after the infection, and also to the rhythm of immune degradation as a result of the infection. This type of comparison, known as association study, permitted to deduct main genetic variations playing a central role in the control of viral infection.
Results point to two gene variants related to the immune system. More precisely, these variations are in a genetic region responsible for the determination of immune response capacity against a number of infectious diseases, including AIDS. These variations are located in the short arm of chromosome 6 in genes controlling HLA-B and HLA-C molecular systems, responsible for the activation of the immune system so that it is able to locate and destroys cells infected by HIV. This study has also identified a third genetic variation involved in immune damage of patients, particularly in a gene encoding a protein which seemingly participates in viral replication, and is also located in chromosome 6.
Genetic variants associated to genes encoding HLA-B and HLA-C molecular systems would explain up to 15% of viral load variation among patients, whereas the third genetic variation would explain 5.8% of these differences. Further study of other genetic regions involved in this process is needed. Nevertheless, HLA-B variation presents the highest correlation with the immune response described until now.

MIT researchers have identified a critical link between two proteins found in brain tumors, a discovery that could eventually help treat a form of brain cancer that kills 99 percent of patients.
Glioblastoma multiforme (GBM), the most aggressive brain tumor in adults, strikes about 15,000 people in the United States each year. GBM is currently treated with a combination of surgery, radiation and chemotherapy, but those treatments have proven ineffective. Most patients die within a year, Science Daily reported.
Now, MIT scientists have uncovered a connection between two proteins found in the tumor cells, and they have demonstrated that attacking both of those proteins kills tumor cells much more effectively than targeting either one alone.
The team focused on a protein called EGFRvIII, a mutated form of the cell receptor for epidermal growth factor (EGF). The mutated receptor, which is found in approximately a quarter of GBM tumors, is continuously active and relentlessly pushes cells to keep growing and dividing.
Doctors have tried treating GBM patients with drugs that inhibit EGFRvIII, but they have had little effect. This could be because the continuous stimulation of the receptor is so intense and because the receptor interacts with numerous other proteins that also promote tumor growth, said White, who is also affiliated with MIT’s Center for Cancer Research and its Computational and Systems Biology Initiative.
The researchers believe it is the cumulative action of EGFRvIII and those other proteins that leads to tumor growth.
“It seems that it is not the activation of one receptor that results in cancer. It’s the action of multiple receptors that leads to the tumors we see,“ said Paul Huang, a graduate student in biological engineering and lead author of the paper. “A potential way to overcome this is to attack multiple targets instead of just one.“
To find out what other proteins are involved in tumor growth, the researchers used a tool known as mass spectrometry to analyze the network of proteins activated by EGFRvIII in GBM tumor cells.
They found that when EGFRvIII is activated, so is another receptor called c-Met. C-Met is normally active during human development, but it’s turned off in most adult cells.
Until now, there had been no evidence of any “cross-talk“ between c-Met and EGFRvIII in GBM. This discovery could offer an explanation for why GBM tumors are so invasive, because over-activated c-Met has already been implicated in very invasive types of lung and breast cancers.
“The mechanism underlying this control has yet to be fully characterized,“ said White. “Our data shows that as EGFRvIII is activated, c-Met is activated as well. Whether it’s direct, or indirect, is something that we are currently deciphering.“

Two new diabetes drugs moderately reduce blood sugar without causing dangerous side effects, a review of more than two dozen studies finds, but the drugs haven’t been on the market long and need to be evaluated for long-term safety and effectiveness, authors say.
The drugs, Byetta and Januvia, along with others not yet on the market, fall into two classes that act on gut hormones called incretins.
Incretins regulate the release of insulin in response to fluctuations in blood sugar. One drug class, which includes Byetta, mimics the effect of incretins; the other class, which includes Januvia, blocks an enzyme that inactivates them, Worldscientist.com said.
When sugar levels return to normal, the drugs stop acting, reducing the risk of hypoglycemia, plunges in sugar levels that can lead to coma if unchecked. Another benefit is that, unlike several other diabetes drugs, these cause no weight gain and may even reduce weight. They can be used by people only with type 2 diabetes, who, unlike type 1 diabetics, produce some insulin.
Anastassios Pittas and colleagues from Tufts-New England Medical Center in Boston analyzed 29 studies that compared incretin drugs with placebo or other diabetes drugs, finding that the new drugs reduce average blood sugar levels by 1 percent or less. Older medications such as metformin reduce glucose levels by up to 2 percent, Pittas says.
The evaluation, known as a meta-analysis, found no alarming signs of dangerous side effects, Pittas says, aside from a slight increase in respiratory and urinary tract infections associated with Januvia and nausea with Byetta.
But, he added, “I would be more comfortable seeing two- and three-year data before embracing them.“

Leaping liquids

After bouncing shampoo, physicists now bring you bouncing cooking oil. A team in Texas has found that the trampolining of a liquid jet falling onto a bath of the same liquid is more common than expected.
Last year, a group in the Netherlands studied this bouncing effect for a jet of shampoo (see ’Puzzle of leaping liquid solved’). The bounce, which was first reported more than 40 years ago, happens because of the peculiar nature of shampoo, which gets thinner (less viscous) as it flows. A jet of it hitting a liquid surface is therefore lubricated by a thin layer at the interface, enabling it to bounce off rather than merge, News@Nature.com reported.
But the liquids now studied by Matthew Thrasher and his colleagues at the University of Texas in Austin don’t have this property. The silicone oils in their experiment are viscous but have ’normal’ flow behaviour, like water1.
The researchers directed a jet of oil vertically onto the surface of a tank of the same oil. They found that the jet could undergo both a ’leaping’ rebound and a bizarre ’flat’ bounce in which it sprang horizontally across the liquid surface.
The bounce here is due to a thin layer of air that separates the two liquid surfaces, the researchers say in an article submitted to Physical Review E.
They point out that the effect can easily be recreated in a kitchen experiment with cooking oil. Just fill a glass pie dish with about 4 centimetres of oil and pour onto it a thin stream from a cup about 3 to 6 centimetres above the surface. While pouring, move the stream in a circle about once every 2 seconds (or perhaps less messily rotate the dish on a Lazy Susan). The bounce can be encouraged by passing a chopstick or some other small rod through the stream every now and then.

Individuals who receive blood transfusions from donors with undiagnosed cancers are at no higher risk of developing malignant disease than people who receive blood from donors without cancer.
Before donated blood can be used in a clinical setting, it must go through tests to ensure that no diseases are passed between the donor and recipient. However, whereas the risk of transmission of infectious agents is well established and appropriate precautions are routinely taken, Physorg.com said.
There is some evidence to support the theory that cancers might be transmissible through blood. Reports of transmission of cancer cells from needles or surgical instruments demonstrate that tumors cells have the capability to be transplanted to, and develop in, healthy recipients. And there is some data to show that transfused patients are at increased risk of cancers, particularly non-Hodgkin lymphoma.
To test some of these ideas, Gustaf Edgren and colleagues set out to investigate whether there is a history of increased cancer diagnoses among individuals that receive blood transfusions from people who donate blood while unaware of their cancers. Researchers created a database from which they identified a group of exposed individuals, who had received donated blood from a person who was diagnosed with cancer less than 5 years after giving blood.
The study population comprised all individuals with no history of malignant disease who had received at least one unit of whole blood, erythrocytes, plasma or platelets between 1968 and 2002. All blood donors who contributed to these transfusions were traced through population and health registers and donors who were subsequently diagnosed with a malignancy within 5 years of the blood donation were deemed to harbor a sub-clinical malignancy at the time of donation.
Recipients of blood from people with a known history of cancer were excluded from the analysis as were those for whom 5 years of follow up was not available. All recipients were followed for cancer occurrence using the Swedish and Danish cancer registries. Any recipients diagnosed with cancer within 6 months of transfusion were excluded.
The researchers identified 978 cases of cancer among all the blood recipients but after statistical analysis they found no excess risk of cancer overall among individuals who had received one or more blood products from a precancerous blood donor.

Decreasing the number of nurses on duty in an intensive care unit (ICU) increases the risk of serious infection, according to a report published in the open access journal Critical Care.
StŽphane Hugonnet and colleagues from the University of Geneva Hospitals, Switzerland, investigated the number of patients admitted to the ICU who developed ventilator-associated pneumonia (VAP), over a four-year period. They then compared this to the number of nurses on duty for each patient in the preceding days. VAP affected over a fifth of the 936 patients who received mechanical ventilation during the study.
The team found that when there were lower numbers of nurses, patients were more likely to catch pneumonia six days or more after being placed on a ventilator. This suggests that bacteria are transferred between patients, or from one site to another in the same patient. This could be due to short-staffed nurses having less time to follow hand hygiene recommendations and proper isolation procedures or being unable to provide adequate care to the ventilated patient. The nurses’ training level had no effect on infection rates.
The authors concluded that this study backs up findings from their earlier general study on ICU infection risks, namely that employing more than two nurses per patient per day would prevent a large proportion of infections. There was an average ratio of two nurses per patient per day in the ICU during this study, Science Daily reported.
“This study shows that a low nurse-to-patient ratio increases the risk of late-onset VAP,“ said Hugonnet. “It adds also to the growing body of evidence demonstrating that adequate staffing is a key determinant and a prerequisite for adequate care and patient safety.“ VAP is caused by bacteria entering the lungs as a consequence of the ventilator tubing and is one of the most common preventable problem affecting critically ill hospital patients. It can cause a stay of about an average of 10 extra days in hospital at a cost of US$10,000 to $40,000.