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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

Comment by Dr. Krishna Kumari Challa on January 29, 2015 at 7:20am

There are so many different genetic forms of autism that using the singular term, autism, is misleading, science researchers on the subject say.

A better term to use while referring to the condition is ‘the autisms,’ or ‘the autism spectrum disorders’ (that is, plural). There are many different forms of autism. In other words, autism is more of a collection of different disorders that have a common clinical manifestation.
The DNA of affected individuals varies remarkably, researchers found. Two-thirds of brothers and sisters with what’s still called autism spectrum disorder, or ASD, showed different genetic changes.
The research results were reported in Nature Medicine.

http://bit.ly/1rgBrwG Nature Medicine

Comment by Dr. Krishna Kumari Challa on January 29, 2015 at 7:16am

Climate, vocal folds, and tonal languages: Connecting the physiological and geographic dots
http://www.pnas.org/content/early/2015/01/14/1417413112.abstract
The sound systems of human languages are not generally thought to be ecologically adaptive. We offer the most extensive evidence to date that such systems are in fact adaptive and can be influenced, at least in some respects, by climatic factors. Based on a survey of laryngology data demonstrating the deleterious effects of aridity on vocal cord movement, we predict that complex tone patterns should be relatively unlikely to evolve in arid climates. This prediction is supported by careful statistical sampling of climatic and phonological data pertaining to over half of the world’s languages. We conclude that human sound systems, like those of some other species, are influenced by environmental variables.
Extensive research on human physiology suggests that really dry air makes it hard for us to use our vocal cords very precisely.
Dry-throat-phenomenon in regards to complex tonal languages, like Cantonese <>, where various combinations of rising and falling tones can actually change the meaning of a word—as opposed to non-tonal languages, like English or Italian.
By mapping the distribution of more than 3,700 tonal and non-tonal languages, Everett and his colleagues found that tonal languages tend to cluster in warm, humid areas. And they're 10 times less prevalent in dry, sub-freezing climes, like Siberia, compared with non-tonal languages.
According to the researchers, language evolves in relation to where it’s spoken. It is not impervious to the effects of environment. Just as ecologies impact human behavior and the adaptive processes of human cultures in myriad ways, they seem to also influence the ways in which languages develop.

Comment by Dr. Krishna Kumari Challa on January 28, 2015 at 9:32am

Immune response: new light
Recognition of rare “foreign” peptides by the alpha-beta T-cell receptor (TCR) on T lymphocytes is critical for the adaptive immune response that protects our bodies. T cell motions during immune surveillance generate forces that are detected by the mechanosensing action of the TCR.

Using single-molecule and single-cell optical tweezer assays, Matthew Lang, Ph.D., and colleagues at Vanderbilt and at the Dana-Farber Cancer Institute in Boston demonstrate that the TCR uses force to enhance binding to foreign peptides and transitions to an extended conformation to release. They found that another part of the TCR complex controls the bond strength and extension transition in this “catch-and-release” model for TCR function.

The findings, reported this week in the Proceedings of the National Academy of Sciences, explain how T-cell receptors are able to seek out and bind to rare foreign peptides among many irrelevant interactions, all with low apparent binding affinity. The research sheds light on how T cells recognize their targets and on strategies for immunotherapies.

Force-dependent transition in the T-cell receptor β-subunit allosterically regulates peptide discrimination and pMHC bond lifetime. Dibyendu Kumar Das et al. PNAS, 2015.

Force-dependent transition in the T-cell receptor β-subunit allosterically regulates peptide discrimination and pMHC bond lifetime. Dibyendu Kumar Das et al. PNAS, 2015. doi:10.1073/pnas.1424829112

Comment by Dr. Krishna Kumari Challa on January 28, 2015 at 9:29am

Beating the clock: Researchers develop new treatment for rabies
Successfully treating rabies can be a race against the clock. Those who suffer a bite from a rabid animal have a brief window of time to seek medical help before the virus takes root in the central nervous system, at which point the disease is almost invariably fatal.

Now, researchers at the University of Georgia have successfully tested a new treatment on mice that cures the disease even after the virus has spread to the brain. They published their findings recently in the Journal of Virology.

"Basically, the best way to deal with rabies right now is simple: Don't get rabies," said study co-author Biao He, a professor of infectious diseases in the UGA College of Veterinary Medicine. "We have vaccines that can prevent the disease, and we use the same vaccine as a kind of treatment after a bite, but it only works if the virus hasn't progressed too far.

"Our team has developed a new vaccine that rescues mice much longer after infection than what was traditionally thought possible."

In their mouse experiments, the animals were exposed to a strain of the rabies virus that generally reaches the brain of infected mice within three days. By day six, mice begin to exhibit the telltale physical symptoms that indicate the infection has become fatal.

However, 50 percent of mice treated with the new vaccine were saved, even after the onset of physical symptoms on day six.

"This is the most effective treatment that has reported in the scientific literature till date"
The researchers developed their vaccine by inserting a protein from the rabies virus into another virus known as parainfluenza virus 5, or PIV5, which is thought to contribute to upper respiratory infections in dogs but is completely harmless to humans.

PIV5 acts as a delivery vehicle that carries the rabies protein to the immune system so it may create the antibodies necessary to fight off the virus.
Apart from being very effective in saving the infected mice, the researchers emphasized that their vaccine is much safer when compared to the best current treatment in mice, which uses a weakened version of the rabies virus.
http://jvi.asm.org/content/early/2014/12/26/JVI.03656-14.full.pdf+html
Parainfluenza virus 5 expressing the G protein of rabies virus protected mice after rabies virus infection J. Virol. JVI.03656-14

Comment by Dr. Krishna Kumari Challa on January 28, 2015 at 9:23am

Cancer uses a little-understood element of cell signaling to hijack the communication process and spread, according to Rice University researchers.

A new computational study by researchers at the Rice-based Center for Theoretical Biological Physics shows how cancer cells take advantage of the system by which cells communicate with their neighbors as they pass messages to “be like me” or “be not like me.”

Led by Rice biophysicists Eshel Ben-Jacob and José Onuchic, the researchers decode how cancer uses a cell-cell interaction mechanism known as notch signaling to promote metastasis. This mechanism plays a crucial role in embryonic development and wound healing and is activated when a delta or jagged ligand of one cell interacts with the notch receptor on an adjacent one.
Cancer cells have the ability to hijack the notch-signaling mechanism that cells use to communicate with each other, especially when “jagged” ligands allow for two-way signaling, according to Rice University scientists. Signals pass between cells when delta or jagged ligands on one bind to external notch proteins on the other.
http://news.rice.edu/2015/01/26/how-cancer-turns-good-cells-to-the-...

At the heart of our new understanding is that the primary agents of metastasis are clusters of hybrid epithelial (nonmobile) and mesenchymal (migrating) cells,” Ben-Jacob said. “These, and not the fully mesenchymal cells, are the ‘bad actors’ of cancer progression that pose the highest risk. By acting together, these hybrid cancer cells have a better chance to evade the immune system during migration and can better survive while circulating in blood vessels.”

The multifaceted mechanism by which notch-delta-jagged signaling promotes cancer progression has been a mystery until now, Ben-Jacob said, but recent experimental studies have revealed the jagged ligand plays a critical role in tumor progression.

The new study provides a fresh theoretical framework for scientists who study the fates of cells. It shows the presence of jagged ligands can give rise to sender/receiver hybrid cells that send a signal — “be like me” — that is useful for embryonic development and healing, but can also be hijacked by cancer cells.

Comment by Dr. Krishna Kumari Challa on January 27, 2015 at 9:31am

The 50 most critical scientific & technological breakthroughs required for sustainable global development
https://www.ligtt.org/50-breakthroughs

Comment by Dr. Krishna Kumari Challa on January 27, 2015 at 7:01am

Why light rain brings sweet aromas:

MIT scientists have identified the mechanism that releases an earthy smell in the air after a light rain.

Using high-speed cameras, the researchers at the Massachusetts Institute of Technology observed that when a raindrop hits a porous surface, it traps tiny air bubbles at the point of contact.

As in a glass of champagne, the bubbles then shoot upward, ultimately bursting from the drop in a fizz of aerosols.

The team was also able to predict the amount of aerosols released, based on the velocity of the raindrop and the permeability of the contact surface.

The researchers suspect that in natural environments, aerosols may carry aromatic elements, along with bacteria and viruses stored in soil. These aerosols may be released during light or moderate rainfall, and then spread via gusts of wind.

This can help in identifying how soil-borne diseases spread.

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