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Comment by Dr. Krishna Kumari Challa on January 6, 2017 at 9:34am

Carbon Chemistry: What is new...Carbon can exceed four-bond limit

A molecule originally proposed more than 40 years ago breaks the rules about how carbon connects to other atoms, scientists have confirmed. In this unusual instance, a carbon atom bonds to six other carbon atoms. That structure, mapped for the first time using X-rays, is an exception to carbon’s textbook four-friend limit, researchers report in the Jan. 2 Angewandte Chemie.

Atoms bond by sharing electrons. In a typical bond two electrons are shared, one from each of the atoms involved. Carbon has four such sharable electrons of its own, so it tends to form four bonds to other atoms.

But that rule doesn’t always hold. In the 1970s, German scientists made an unusual discovery about a molecule called hexamethylbenzene. This molecule has a flat hexagonal ring made of six carbon atoms. An extra carbon atom sticks off each vertex of the ring, like six tiny arms. Hydrogen atoms attach to the ring’s arms. And leftover electrons zip around the middle of the ring, strengthening the bonds and making the molecule more stable. 

When the scientists removed two electrons from the molecule, leaving it with a positive charge, some evidence suggested it might dramatically change its shape. It seemed to rearrange so that one carbon atom was bonded to six other carbons.

A  different lab has revisited the question. 

When hexamethylbenzene lost two electrons, it reordered itself. One carbon atom jumped out of the ring and took a new position on top, turning the flat hexagonal ring into a five-sided carbon pyramid. And the carbon on top of the pyramid was indeed bonded to six other carbons — five in the ring below, and one above.

This molecule is very exceptional. Though scientists have found other exceptions to carbon’s four-bond limit, this is the first time carbon has been shown associating with this many other carbon atoms.

When scientists measured the length of the molecule’s chemical bonds, the top carbon’s six bonds were each a bit longer than an ordinary carbon-carbon bond. A longer bond is generally less strong. So by picking more partners, that carbon has a slightly weaker connection to each one.

The carbon isn’t making six bonds in the sense that we usually think of a carbon-carbon bond as a two-electron bond. That’s because the carbon atom still has only four electrons to share. As a result, it spreads itself a bit thin by sharing electrons among the six bonds.

Comment by Dr. Krishna Kumari Challa on January 6, 2017 at 9:01am

People who live near roads laden with heavy traffic face a higher risk of developing dementia than those living further away, possibly because pollutants get into their brains via the blood stream, according to researchers in Canada.

A study in The Lancet medical journal found that people who lived within 50 metres (55 yards) of high-traffic roads had a 7.0 percent higher chance of developing dementia compared to those who lived more than 300 metres away from busy roadways.

Air pollutants can get into the blood stream and lead to inflammation, which is linked with cardiovascular disease and possibly other conditions such as diabetes. This study suggests air pollutants that can get into the brain via the blood stream can lead to neurological problems.

Comment by Dr. Krishna Kumari Challa on January 5, 2017 at 8:57am

Disturbing facts: Approximately half of studies published on new medical treatments leave out at least some of the adverse effects they uncovered, according to a recent analysis in PLOS Medicine. A team of British researchers conducted the review after coming across individual cases of missing side effects in medical literature, which includes studies from pharmaceutical companies, hospitals and academics. To determine how widespread the problem was, they analyzed 28 journal articles that together cross-checked the published data from more than 500 clinical studies with their original data sets. The review's results quantitatively confirm that some drugs may have side effects not even doctors know about—which means treatments may not be as safe as they appear.

• These findings suggest that researchers should search beyond journal publications for information on side effects of treatments.
• These findings also support the need for the drug industry to release full data on side effects so that a complete picture can be given to health professionals, policy makers, and patients.

http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pm...

Reporting of Adverse Events in Published and Unpublished Studies of Health Care Interventions: A Systematic Review

Comment by Dr. Krishna Kumari Challa on January 5, 2017 at 7:02am

Comment by Dr. Krishna Kumari Challa on January 3, 2017 at 7:41am

Languages Are Still a Major Barrier to Global Science

A third of new scientific findings are published in languages other than English, contributing to biases in our understanding and hinderances to the advance of science and research, a new study has found.

English is now considered the common language of global science. All major scientific journals seemingly publish in English, despite the fact that their pages contain research from across the globe.

Language hinders new findings getting through to practitioners in the field and causes the international community missing important science, said researchers from the University of Cambridge in the UK.

They argue that whenever science is only published in one language, barriers to the transfer of knowledge are created.

The researchers call on scientific journals to publish basic summaries of a studys key findings in multiple languages and universities to encourage translations as part of their outreach evaluation criteria.

The researchers point out an imbalance in knowledge transfer in countries where English is not the mother tongue - much scientific knowledge that has originated there is available only in English and not in their local languages.

Researchers surveyed the web platform Google Scholar in a total of 16 languages for studies on biodiversity conservation published during a single year, 2014.

Of the over 75,000 documents, including journal articles, books and theses, some 35.6 per cent were not in English.

Of these, the majority was in Spanish (12.6 per cent) or Portuguese (10.3 per cent). Simplified Chinese made up six per cent and three per cent were in French.

Random sampling showed that only around half of non-English documents included titles or abstracts in English.

This means that around 13,000 documents on conservation science published in 2014 are unsearchable using English keywords.

This can result in sweeps of current scientific knowledge - known as systematic reviews - being biased towards evidence published in English, researchers said.

This, in turn, may lead to over-representation of results considered positive or statistically significant, and these are more likely to appear in English language journals deemed high-impact.

In addition, information on areas specific to countries where English is not the mother tongue can be overlooked when searching only in English.

For environmental science, this means important knowledge relating to local species, habitats and ecosystems - but also applies to diseases and medical sciences.

But native English speakers tend to assume that all the important information is available in English which is not the case in real terms. On the other hand, non-native English speakers tend to think carrying out research in English is the first priority, often ending up ignoring non-English science and its communication.

The research was published in the journal PLOS Biology.

http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbi...

Comment by Dr. Krishna Kumari Challa on December 30, 2016 at 9:55am

Vera Rubin Didn't Discover Dark Matter

https://blogs.scientificamerican.com/guest-blog/vera-rubin-didnt-di...

Comment by Dr. Krishna Kumari Challa on December 29, 2016 at 10:32am

Scientists face Intimidation and death threats in the US!

Troubling Signs for Science under Trump

The next four years are looking grim for science in America

https://blogs.scientificamerican.com/rosetta-stones/troubling-signs...

Comment by Dr. Krishna Kumari Challa on December 28, 2016 at 11:31am

The Postmortem Skin Microbiome to Estimate the Postmortem Interval

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.01...

Necrobiome. Heard about it before? It is the microbiological ecology of dead bodies. The genetic signatures of that microbial community as it waned and waxed after death can be used to build an algorithm that could pinpoint a corpse's time of death, to an accuracy of just two summertime days and can be used in forensic science.

Comment by Dr. Krishna Kumari Challa on December 28, 2016 at 11:18am

China's pollution is causing millions of premature deaths.

A team of researchers led by Professor Zhu Tong from Peking university used PM2.5 data from over 500 ground observation stations in China, re-analyzing them using a newly developed integrated exposure-response (IER) model to estimate the risk of premature death due to exposure to PM2.5. They found that 84 percent of China’s population live in areas where the yearly average PM2.5 exceeded 35 micrograms per cubic meter, the upper limit set in ambient air quality standards by the World Health Organization. Their model predicted that this exposure to high PM2.5 levels resulted in 1.37 million premature deaths, of which 50 percent, 28 percent and 12 percent were due to cerebrovascular disease, ischemic heart disease and chronic obstructive pulmonary disease respectively. The study also points out that if the concentration of PM2.5 meets the WHO standards, the risk of premature death can decrease by 39 percent, 23 percent and 66 percent respectively, revealing the non-linear relationship between the decrease of PM2.5 and the improvement of different health conditions. 

Estimating adult mortality attributable to PM_2.5 exposure in China with assimilated PM_2.5 concentrations based on a ground monitoring network

http://www.sciencedirect.com/science/article/pii/S0048969716310956

Comment by Dr. Krishna Kumari Challa on December 20, 2016 at 11:31am

Earth’s surface is shattered by roads into over 600,000 fragments – more than half of which are smaller that one square kilometre – severely reducing the ability of ecosystems to function effectively, a new study has found.

Roads have made it possible for humans to access almost every region but this comes at a very high cost ecologically to the planet’s natural world. Despite substantial efforts to conserve the world’s natural heritage, large tracts of valuable roadless areas remain unprotected, researchers said.

The researchers from the Eberswalde University for Sustainable Development in Germany used a dataset of 36 million kilometres of roads across the landscapes of the earth. They are dividing them into more than 600,000 pieces that are not directly affected by roads.

Of these remaining roadless areas only seven per cent are larger than 100 square kilometres. The largest tracts are to be found in the tundra and the boreal forests of North America and Eurasia, as well as some tropical areas of Africa, South America and Southeast Asia. Only nine per cent of these areas undisturbed by roads are protected.

Roads introduce many problems to nature. For instance, they interrupt gene flow in animal populations,facilitate the spread of pests and diseases, and increase soil erosion and the contamination of rivers and wetlands.

Then there is the free movement of people made possible by road development in previously remote areas, which has opened these areas up to severe problems such as illegal logging, poaching and deforestation.

Most importantly, roads trigger the construction of further roads and the subsequent conversion of natural landscapes, a phenomenon the study labels “contagious development.”

“Our global map provides guidance on the location of the most valuable roadless areas,” said Pierre Ibisch, from the Eberswalde University. In many cases they represent remaining tracks of extensive functional ecosystems, and are of key significance to ecological processes, such as regulating the hydrological cycle and the climate,” said Ibisch.

The researchers used a large data base generated through crowd-sourcing platform to produce a global map for roadless.

All roads affect the environment in some shape or form including timber extraction tracks and minor dirt roads, and the impacts can be felt far beyond the road edge.

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