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Comment by Dr. Krishna Kumari Challa on February 5, 2015 at 6:50am

A team of researchers from MIT and the University of Liege, in Belgium, have shown through high-speed images of raindrops splashing down on leaves that raindrops can act as a dispersing agent of contaminated droplets from one plant to another.

Comment by Dr. Krishna Kumari Challa on February 4, 2015 at 9:43am

Mercury levels in Hawaiian Yellowfin tuna – known as ahi on the plate – are on the rise, scientists report February 2 in Environmental Toxicology and Chemistry.

Data collected in 1998 and 2008 showed that mercury levels increased at a rate of about 3.8 percent per year, the researchers say. A tuna about 75 kilograms in size might have had about 0.4 parts per million of mercury in its body in 1998. In 2008, the same-sized fish would have had around 0.6 parts per million.

The tuna’s increase in toxic baggage mirrors increasing levels of mercury pollution from human activities, such as burning coal in power plants and mining.
http://onlinelibrary.wiley.com/doi/10.1002/etc.2883/abstract

Comment by Dr. Krishna Kumari Challa on February 4, 2015 at 9:06am

Is there a The Best Position For Birth?
The time honored tradition of elevating women 15 degrees during birth does not actually reduce venous compression, study says.
New research is challenging what many obstetricians and physician anesthesiologists believe is the best way to position women during labor. According to a study published in Anesthesiology, the traditional practice of positioning women on their side does not effectively reduce compression of the inferior vena cava, a large vein located near the abdominal area that returns blood to the heart, as previously thought. "It is widely believed that lying women flat on their back during labor can lead to dangerously low blood pressure caused by the compression of both the inferior vena cava and the aorta due to the weight of the fetus," said Dr. Hideyuki Higuchi, study author from Tokyo Women's Medical University. "It is accepted by many physicians that positioning women on their side, with hips tilted at 15 degrees, during childbirth reduces this complication. However, our research found no evidence of aortic compression in pregnant women in any position and the recommended degree of tilt that most physicians follow did not reduce compression of the inferior vena cava at all. This is the first study to challenge this antiquated practice." In the study, magnetic resonance images (MRI) of ten pregnant women at full term and ten non-pregnant women were obtained for measurement of the abdominal aorta, the largest artery in the abdominal cavity, and the inferior vena cava. Measurements were taken while the women laid flat on their back and while tilted at 15, 30, and 45 degrees. Foam was placed under the right side of the study participants to achieve the desired amount of tilt. The study found that abdominal aortic blood volume did not differ significantly between pregnant and non-pregnant women regardless of the position in which they were placed. Conversely, inferior vena cava blood volume was significantly lower in pregnant women than in non-pregnant women when the women were positioned flat on their back, indicating almost complete compression of the vein. Inferior vena cava blood volume did not increase at 15 degrees, but partially increased at 30 degrees. An accompanying editorial commented favorably on the study's results, but offered a word of caution: "Although it would be great to be able to conclude by saying all of our patients in the delivery room should be placed in at least 30 degrees left lateral tilt after regional anesthetic, I have serious doubts that our obstetric colleagues would find it a reasonable position for cesarean delivery, particularly in obese patients," said editorial author Dr. Craig Palmer from the University of Arizona College of Medicine. "There quite probably are patients for whom the modest (15 degree) tilt we apply has a salutary effect. However, I will have to be less dogmatic about the practice. Kudos to the authors of this study for revisiting an 'ancient' practice, applying current technology to the matter, and shedding new light on an old routine." The article can be found at: Higuchi et al. (2015) Effect of Lateral Tilt Angle on the Volume of the Abdominal Aorta and Inferior Vena Cava in Pregnant and Nonpregnant Women Determined by Magnetic Resonance Imaging.
Source: American Society of Anesthesiologists.

Comment by Dr. Krishna Kumari Challa on February 4, 2015 at 8:39am

Gravitational waves discovery now officially dead

Combined data from South Pole experiment BICEP2 and Planck probe point to Galactic dust as confounding signal.
A team of astronomers that last year reported evidence for gravitational waves from the early Universe has now withdrawn the claim. A joint analysis of data recorded by the team's BICEP2 telescope at the South Pole and by the European spacecraft Planck has revealed that the signal can be entirely attributed to dust in the Milky Way rather than having a more ancient, cosmic origin.

The European Space Agency (ESA) announced the long-awaited results on January 30, a day after a summary of it had been unintentionally posted online by French members of the Planck satellite team and then widely circulated before it was taken down.
http://www.nature.com/news/gravitational-waves-discovery-now-offici...

Comment by Dr. Krishna Kumari Challa on February 1, 2015 at 10:16am

The hepatitis-liver cancer connection...
Using whole genomic sequencing, scientists from RIKEN in Japan have for the first time demonstrated the profound effect that chronic hepatitis infection and inflammation can have on the genetic mutations found in tumors of the liver, potentially paving the way to a better understanding of the mechanisms through which these chronic infections can lead to cancer. Recent studies have shown that particularly in Asia, infection with either hepatitis B or C is often associated with such cancers.
For the study, which was published in Nature Communications, the group performed whole genomic sequencing on 30 individual tumors classified as liver cancer displaying a biliary phenotype. This type of cancer originates in the liver, but is different from hepatocellular carcinoma, the dominant form of primary liver cancer, and is generally more aggressive, with poorer prognosis. They compared the data with 60 of the more-common hepatocellular carcinoma tumors. To study gene expression, they then examined RNA sequencing data from 25 of the biliary-phenotype cancers and 44 hepatocellular cancers.
Surprisingly, they found that although the patterns of gene expression—as shown by the RNA sequencing—differed between the hepatocellular carcinomas and the liver cancers with biliary phenotype and depended on the histological type, the overall pattern of mutations in the cells was actually similar between the tumors—of either type—that had emerged in patients who had had infections with either hepatitis C or B, and were different in patients without such infections. This same kind of clustering is also found in cancers with well-understood etiologies, such as melanoma (UV light) and lung cancer (smoking). According to Hidewaki Nakagawa of the RIKEN Center for Integrative Medical Sciences, who led the team, "This is an interesting finding and could indicate that the cancers—even of different histological types—in patients with hepatitis infections could be derived from similar cells, perhaps hepatic progenitor cells. In patients without hepatitis, we did not find any clustering, and this indicates that their cancers might have a very different cellular origin."

Through the analysis, researchers were also able to identify changes in mutations that are associated with more aggressive biliary-type liver cancers. Specifically, they found that mutations of KRAS and IDHs, which are linked to more aggressive cancers, were less common in the cancers in patients with chronic hepatitis.
http://www.nature.com/ncomms/2015/150130/ncomms7120/full/ncomms7120...

Comment by Dr. Krishna Kumari Challa on February 1, 2015 at 9:44am

Comment by Dr. Krishna Kumari Challa on January 31, 2015 at 12:42pm

Norovirus, the most common cause of gastroenteritis in the world, can be killed with "cold plasma," researchers in Germany have reported.

The virus, which elicits vomiting and diarrhea, has gained international notoriety for causing outbreaks on cruise ships.

However, such incidents represent merely a fraction of the tens of millions of cases that occur around the world each year.

The research appears in mBio journal.

Preventing norovirus outbreaks is complicated by the fact that the virus is highly resistant to several different chemical disinfectants.

Bleach, a chlorine-based solution, is currently the most effective treatment, but researchers are seeking more convenient alternatives.

One such alternative is cold plasma, also known as non-thermal plasma. This "fourth state of matter" consists of ionized gas molecules at room temperature. These ions can destroy many kinds of microbes, but their effect on viruses was less clear.

Inactivation of a Foodborne Norovirus Outbreak Strain with Nonthermal Atmospheric Pressure Plasma
http://mbio.asm.org/content/6/1/e02300-14.full

Comment by Dr. Krishna Kumari Challa on January 30, 2015 at 9:17am

I always wondered about this and I got a few answers to my questions now on psychopathics: It seems Psychopathic violent offenders' brains can't understand punishment!

Psychopathic violent offenders have abnormalities in the parts of the brain related to learning from punishment, according to an MRI study led by Sheilagh Hodgins and Nigel Blackwood. “One in five violent offenders is a psychopath. They have higher rates of recidivism and don't benefit from rehabilitation programmes. their research reveals why this is and can hopefully improve childhood interventions to prevent violence and behavioural therapies to reduce recidivism”.

Psychopathic offenders are different from regular criminals in many ways. Regular criminals are hyper-responsive to threat, quick-tempered and aggressive, while psychopaths have a very low response to threats, are cold, and their aggressively is premeditated. Evidence is now accumulating to show that both types of offenders present abnormal, but distinctive, brain development from a young age.”

In order to develop programs that prevent offending and rehabilitation programs that reduce re-offending, it is essential to identify the neural mechanisms underlying psychopath's persistent violent behaviour. They have been using Magnetic Resonance Imaging to study brain structure and function in a sample of violent offenders in England, one group with psychopathy and one without, and a sample of healthy non-offenders. They have found structural abnormalities in both gray matter and specific white matter fiber tracts among the violent offenders with psychopathy. Grey matter is mostly involved with processing information and cognition, while white matter coordinates the flow of information between different parts of the brain.

The researchers observed reductions in gray matter volumes bilaterally in the anterior rostral prefrontal cortex and temporal poles relative to the other offenders and to the non-offenders. These brain regions are involved in empathy, the processing of pro-social emotions such as guilt and embarrassment, and moral reasoning. “Abnormalities were also found in white matter fiber tracts in the dorsal cingulum, linking the posterior cingulate cortex to the medial prefrontal cortex that were specifically associated with the lack of empathy that is typical of psychopathy. These same regions are involved in learning from rewards and punishment. In childhood, both psychopathic and non-psychopathic offenders alike are repeatedly punished by parents and teachers for breaking rules and for assaulting others, and from adolescence onwards, they are frequently incarcerated. Yet they persist in engaging in violent behaviour towards others. Thus, punishment does not appear to modify their behaviour. They found that the violent offenders with psychopathy, as compared to both the violent offenders without psychopathy and the non-offenders, displayed abnormal responding to punishment within the posterior cingulate and insula when a previously rewarded response was punished. Deciding on what to do involves generating a list of possible actions, weighing the negative and positive consequences of each, and hopefully choosing the behaviour most likely to lead to a positive outcome. Offenders with psychopathy may only consider the possible positive consequences and fail to take account of the likely negative consequences. Consequently, their behavior often leads to punishment rather than reward as they had expected. “Punishment signals the necessity to change behaviour. Clearly, in certain situations, offenders have difficulty learning from punishment to change their behaviour.”

http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366%2814...

Comment by Dr. Krishna Kumari Challa on January 30, 2015 at 7:31am

New light on comets: Courtesy Rosetta:
The European Space Agency's Rosetta mission has now found that Comet 67P/Churyumov–Gerasimenko's is even stranger than initially expected.
The new comet findings, detailed in a special issue of the journal Science this week, are even calling into question an old axiom of comet research.
1. Many scientists have dubbed comets "dirty snowballs," but now it might be more appropriate to call this comet a "snowy dustball" because of its dust-to-gas ration.
2. Researchers working with Rosetta have found that the comet harbors organic compounds, carbon-based molecules that are sometimes known as the chemical building blocks of life. This marks the first time organic molecules have been detected on the surface of a comet's nucleus, according to Fabrizio Capaccioni, the principal investigator of the VIRTIS instrument on Rosetta.
3. The northern hemisphere of the comet's nucleus is also filled with dunes and ripples that look somewhat like geological markings on Earth, Mars and Venus. Comet 67P/C-G doesn't have a robust atmosphere and high gravity like those planets, and yet it still has structures resembling sand dunes. It's possible that the comet's outgassing in the active region on the comet could cause the odd surface features. The high-speed gas flows from the regions, expanding into the vacuum of space, and potentially creating the features.
4. If a person were to stand on the surface of the comet, he or she could jump very high into space because of Comet 67P/C-G's low gravity. The composition of the comet is also very diverse. You might sink in into the smooth dust where we find the thick snow-field like layers, other areas might be robust enough to carry you.
5. Comet 67P/C-G is very dark—darker than charcoal—without much water-ice on its surface potentially because it has taken multiple trips around the sun, burning off much of its ice. Right now, most of the comet's jet-creating activity is happening from the cliffs and pit walls.
6. Another study in Science this week also details new research about the temperature of the comet. It was found that the northern hemisphere of the comet is relatively warm, while the southern hemisphere is somewhat colder, indicating seasonal changes on Comet 67P/C-G.
7. Rosetta's findings have also potentially upturned a theory about how water was delivered to the early Earth. Many scientists think that comets brought Earth its water; however, the type of water found in Comet 67P/C-G is sodifferent from terrestrial water that some researchers are starting to second-guess that claim, opting instead to look at asteroids as the objects that delivered water to Earth at first.

- Space.com

Comment by Dr. Krishna Kumari Challa on January 30, 2015 at 7:14am

RNAs proofread themselves!
Molecular photographs of an enzyme bound to RNA reveal a new, inherent quality control mechanism
Building a protein is a complicated process. Information is passed along from one messenger to another, creating the potential for errors every step of the way. There are separate, specialized enzymatic machines that proofread at each step, ensuring that the instructions encoded in our DNA are faithfully translated into proteins. Scientists at Cold Spring Harbor Laboratory (CSHL) have uncovered a new quality control mechanism along this path, but in a remarkable role reversal, the proofreading isn't done by an enzyme. Instead, one of the messengers itself has a built-in mechanism to prevent errors along the way.

The building blocks for proteins are carried by molecules known as transfer RNAs (tRNAs). tRNAs work with other cellular machinery to ensure that the building blocks - amino acids - are arranged in the proper order. But before a building block can be loaded onto a tRNA molecule, a three-part chemical sequence that scientists call "CCA" must be added to the tRNA. The letters are added by an appropriately named machine, the CCA-adding enzyme, and they mark the tRNA as a fully functional molecule.

If a tRNA is mutated, the CCA-adding enzyme duplicates its message. The letters now read "CCACCA," signaling that the tRNA is flawed. The cell rapidly degrades the aberrant tRNA, preventing the flawed message from propagating.

But how does the CCA-adding enzyme distinguish between normal and mutant tRNAs?

CSHL Professor and Howard Hughes Medical Institute Investigator Leemor Joshua-Tor led a team of researchers to investigate how the CCA-adding enzyme makes this distinction. "We used X-ray crystallography - a type of molecular photography - to observe the enzyme at work, and we were surprised to find that the enzyme doesn't discriminate at all," explains Joshua-Tor. "In fact, it is the RNA that is responsible for proofreading itself."

The team used two tRNA-like molecules, called noncoding RNAs, to study the error-correcting mechanism. In previous work, Jeremy Wilusz, PhD, a former CSHL Watson School of Biological Sciences graduate student and an author on this current publication, found a noncoding RNA that is modified with a single CCA group, making it both stable and abundant. Another RNA used in the current study is normally present at negligible levels in cells, and Wilusz and CSHL Professor David Spector found that it is modified with a CCACCA sequence and is rapidly degraded. The difference between the two noncoding RNAs is a simple mutation, and the question the team addressed is how the presence of the mutation affects the addition of "CCA" sequences.

In work published in Cell's on line edition.
http://www.cell.com/cell/abstract/S0092-8674%2815%2900006-9

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