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Archive for the ‘chemistry’ category: Page 287

Feb 3, 2017

Neutrons reveal ‘quantum tunnelling’ on graphene enables the birth of stars

Posted by in categories: chemistry, nanotechnology, particle physics, quantum physics, space travel

Graphene is known as the world’s thinnest material due to its 2-D structure, in which each sheet is only one carbon atom thick, allowing each atom to engage in a chemical reaction from two sides. Graphene flakes can have a very large proportion of edge atoms, all of which have a particular chemical reactivity. In addition, chemically active voids created by missing atoms are a surface defect of graphene sheets. These structural defects and edges play a vital role in carbon chemistry and physics, as they alter the chemical reactivity of graphene. In fact, chemical reactions have repeatedly been shown to be favoured at these defect sites.

Interstellar molecular clouds are predominantly composed of hydrogen in molecular form (H2), but also contain a small percentage of dust particles mostly in the form of carbon nanostructures, called polyaromatic hydrocarbons (PAH). These clouds are often referred to as ‘star nurseries’ as their low temperature and high density allows gravity to locally condense matter in such a way that it initiates H fusion, the nuclear reaction at the heart of each star. Graphene-based materials, prepared from the exfoliation of graphite oxide, are used as a model of interstellar carbon dust as they contain a relatively large amount of , either at their edges or on their surface. These defects are thought to sustain the Eley-Rideal chemical reaction, which recombines two H into one H2 molecule.

The observation of interstellar clouds in inhospitable regions of space, including in the direct proximity of giant stars, poses the question of the origin of the stability of hydrogen in the molecular form (H2). This question stands because the clouds are constantly being washed out by intense radiation, hence cracking the hydrogen molecules into atoms. Astrochemists suggest that the chemical mechanism responsible for the recombination of atomic H into molecular H2 is catalysed by carbon flakes in interstellar clouds. Their theories are challenged by the need for a very efficient surface chemistry scenario to explain the observed equilibrium between dissociation and recombination. They had to introduce highly reactive sites into their models so that the capture of an atomic H nearby occurs without fail.

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Feb 1, 2017

Missouri S&T researcher works to develop nanodiamond materials

Posted by in categories: biotech/medical, chemistry, military, nanotechnology, particle physics

Nice.


When you think of diamonds, rings and anniversaries generally come to mind. But one day, the first thing that will come to mind may be bone surgery. By carefully designing modified diamonds at the nano-scale level, a Missouri University of Science and Technology researcher hopes to create multifunctional diamond-based materials for applications ranging from advanced composites to drug delivery platforms and biomedical imaging agents.

Dr. Vadym Mochalin, an associate professor of chemistry and materials science and engineering at Missouri S&T, is characterizing and modifying 5-nanometer nanodiamond particles produced from expired military grade explosives so that they can be developed to perform specific tasks. His current research studies their use as a filler in various types of composites.

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Jan 19, 2017

Will synthetic biology help us to eliminate age-related diseases?

Posted by in categories: bioengineering, biotech/medical, chemistry, computing, genetics, health, life extension

A quick look at synthetic biology and its potential for health and treating age-related diseases.


All living organisms contain an instruction set that determines what they look like and what they do. These instructions are encoded in the organism’s DNA within every cell, this is an organism’s genetic code (or “genome”).

Mankind has been altering the genetic code of plants and animals for thousands of years, by selectively breeding individuals with desired features. Over time we have become experts at viewing and manipulating this code, and we can now take genetic information associated with the desired features from one organism, and add it into another one. This is the basis of genetic engineering, which has allowed us to speed up the process of developing new breeds of plants and animals.

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Jan 17, 2017

Messy Chemistry, Evolving Rocks, and the Origin of Life

Posted by in categories: chemistry, evolution

Noted synthetic life researcher Steven Benner of Foundation for Applied Molecular Evolution is fond of pointing out that gooey tars are the end product of too many experiments in his field. His widely-held view is that the tars, made out of chemicals known to be important in the origin of life, are nonetheless a dead end to be avoided when trying to work out how life began.

But in the changing world of origins of life research, others are asking whether those messy tars might not be a breeding ground for the origin of life, rather than an obstacle to it.

One of those is chemist and astrobiologist Irena Mamajanov of the Earth-Life Science Institute (ELSI) in Tokyo. As she recently explained during an institute symposium, scientists know that tar-like substances were present on early Earth, and that she and her colleagues are now aggressively studying their potential role in the prebiotic chemical transformations that ultimately allowed life to emerge out of non-life.

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Jan 13, 2017

Making hydrogen from wax

Posted by in categories: chemistry, energy, transportation

This publication suggests that wax could be carried on vehicles and used to create hydrogen gas in situ, the waste carbon being used to make more wax via syngas production and the Fischer-Tropsch process, where carbon monoxide and hydrogen is converted into hydrocarbons as a potential source of petro-chemicals that does not involve releasing fossil carbon into the atmosphere. While this publication is still a long way from a working industrial-scale process, it offers a very hopeful potential avenue for less-polluting technology.


Philip recently attended an event for other Oxford University chemistry alumni, and one of the speakers drew attention to a recent publication from, among others, Oxford chemists, regarding the production of hydrogen from paraffin waxes by microwave degradation using a ruthenium catalyst.

Hydrogen has often been suggested as an environmentally-friendly replacement energy source for fossil fuels in transport vehicles and other applications requiring high energy density. (Note that hydrogen is not a “fuel”, as it must be made using energy from other sources, which can be environmentally-friendly or not.) However, there are significant problems with this, notably involving the safe storage of a highly-inflammable and explosive gas which is much lighter than air.

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Jan 13, 2017

Forget What You Learned in High School

Posted by in categories: chemistry, education

It’s the stuff of Chemistry 101: carbon can only form four bonds because it only has four shareable electrons.

But this rule no longer applies, because scientists have confirmed the existence of an exotic carbon molecule that can form six bonds, meaning the most classic example of tetravalence in our high school chemistry textbooks now comes with a hefty caveat.

If all of this is kinda giving you conniptions, we’re right there with you.

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Jan 5, 2017

Nano-chimneys can cool circuits

Posted by in categories: chemistry, nanotechnology

Very cool.


A few nanoscale adjustments may be all that is required to make graphene-nanotube junctions excel at transferring heat, according to Rice University scientists.

The Rice lab of theoretical physicist Boris Yakobson found that putting a cone-like “chimney” between the graphene and nanotube all but eliminates a barrier that blocks heat from escaping.

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Dec 15, 2016

New structure shows how cells assemble protein-making machinery

Posted by in categories: chemistry, nanotechnology, particle physics, robotics/AI

Scientists at The Rockefeller University have created the most detailed three-dimensional images to date of an important step in the process by which cells make the nano-machines responsible for producing all-important protein. The results, described December 15 in Science, are prompting the researchers to re-evaluate how they envision this early phase in the construction of ribosomes.

“The structure they determined, shown above, belongs to a particle formally called the “small subunit processome.” Before this particle can fulfill its destiny to become the smaller half of a complete ribosome, the RNA within it needs to be folded, tweaked, and cut.

“Initially, we thought of the small subunit processome as a product on an assembly line, with molecular workers arriving from outside, much like the robots that would put together a car. But that analogy no longer appears apt,” says senior author Sebastian Klinge, head of the Laboratory of Protein and Nucleic Acid Chemistry.

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Dec 6, 2016

Ukrainian Scientist Creates Battery That Can Power Smartphones for 12 Years

Posted by in categories: chemistry, mobile phones, transportation

Ukrainian scientist Vladislav Kiselev claims that he has developed a type of battery that can power gadgets like smartphones and even cars for up to 12 years, without having to be recharged.

Kiselev, a senior researcher at the Institute of Bioorganic Chemistry and Petrochemistry in Kiev, and professor at Ukraine’s National Academy of Sciences, unveiled his intriguing battery prototype during the 2016 edition of Sikorsky Challenge, a prestigious international competition for research projects. The matchbox-like device looks fairly unimpressive, but the Ukrainian scientist claims that it has been continuously powering electrical devices for a year and four months without a single recharge, and will continue to do so for the next 11 years. That’s because his “battery” produces energy instead of simply storing it.

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Nov 30, 2016

Scientists design living organisms that make chemical bonds not found in nature

Posted by in categories: alien life, biological, chemistry

Move over, chemists. Thanks to proteins from Icelandic bacteria, scientists at Caltech have managed to coax microbes into making silicon-carbon bonds, a feat that until now has been achieved only by humans in the lab.

The findings, published last week in the journal Science, could open the door to new avenues in organic chemistry and drug development — and could help scientists investigate essential mysteries, such as whether life could be based on silicon instead of carbon on other planets.

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