Showing posts with label chemistry. Show all posts
Showing posts with label chemistry. Show all posts

Monday, October 28, 2013

Scientists who took chemistry into cyberspace win Nobel Prize

University of Southern California professor Arieh Warshel talks on the phone with Israeli President Shimon Peres after hearing he won the Nobel chemistry prize in Los Angeles, California October 9, 2013. REUTERS/Lucy Nicholson


1 of 10. University of Southern California professor Arieh Warshel talks on the phone with Israeli President Shimon Peres after hearing he won the Nobel chemistry prize in Los Angeles, California October 9, 2013.

Credit: Reuters/Lucy Nicholson

By Mia Shanley and Sven Nordenstam


STOCKHOLM | Wed Oct 9, 2013 3:21pm EDT


STOCKHOLM (Reuters) - Three U.S. scientists won the Nobel chemistry prize on Wednesday for pioneering work on computer programs that simulate complex chemical processes and have revolutionized research in areas from drugs to solar energy.


The Royal Swedish Academy of Sciences, awarding the prize of 8 million crowns ($1.25 million) to Martin Karplus, Michael Levitt and Arieh Warshel, said their work had effectively taken chemistry into cyberspace. Long gone were the days of modeling reactions using plastic balls and sticks.


"Today the computer is just as important a tool for chemists as the test tube," the academy said in a statement. "Computer models mirroring real life have become crucial for most advances made in chemistry today."


Chemical reactions occur at lightning speed as electrons jump between atomic nuclei, making it virtually impossible to map every separate step in chemical processes involving large molecules like proteins.


Powerful computer models, first developed by the three scientists in the 1970s, offer a new window onto such reactions and have become a mainstay for researchers in thousands of academic and industrial laboratories around the world.


'LIKE A MOVIE'


In drug design, for example, scientists can now use computers to calculate how an experimental medicine will react with a particular target protein in the body by working out the interplay of atoms.


"The field of computational modeling has revolutionized how we design new medicines by allowing us to accurately predict the behavior of proteins," said Dominic Tildesley, president-elect of Britain's Royal Society of Chemistry.


Today, all pharmaceutical companies use computational chemistry to screen experimental compounds for potential as medicines before further testing them on animals or people.


The ability to model chemical reactions has also grown as computers have become more powerful, while progress in biotechnology has produced ever more complex large molecules for use in treating diseases like cancer and rheumatoid arthritis.


"It has revolutionized chemistry," Kersti Hermansson, professor in organic chemistry at Uppsala University, said of the computer modeling. "When you solve equations on the computer, you obtain information that is at such detail it is almost impossible to get it from any other method."


"You can really follow like a movie, in time and in space. This is fantastic detail..."


Karplus, a U.S. and Austrian citizen, carries out research at the University of Strasbourg and Harvard University. Levitt, a U.S. and British citizen, is at the Stanford University School of Medicine. Warshel, a U.S. and Israeli citizen, is a professor at the University of Southern California, Los Angeles.


The approach has applications in industrial processes, such as materials science, the design of solar cells or catalysts used in cars. For the former, programs can be used to mimic the process of photosynthesis by which green leaves absorb sunlight and produce oxygen.


EARLY SETBACKS


It was not an easy scientific journey, however. Warshel said he had been convinced of the case for using computers to simulate chemical reactions since 1975 but did not know if he would live to see it adopted.


"I always knew it was the right direction, but I had infinite difficulties and setbacks in the research. None of my papers were ever published without being rejected first," he told Reuters.


Karplus said his early work using computers was initially met coldly by many of his scientific colleagues in the '70s.


"My chemistry colleagues thought it was a waste of time," he told reporters at Harvard in Cambridge, Massachusetts, adding that the next generation of scientists should be courageous and "not believe their colleagues necessarily if they say they can't do something."


Karplus's family brought him to the United States in 1938 after the Nazi annexation of Austria. Austrian President Heinz Fischer said on Wednesday the Nobel Committee's decision to award the prize to Karplus "is gratifying and at the same time an occasion to reflect on Austria's responsibility."


A unique insight of the trio's work was to use computer simulations to combine quantum mechanics, which explains the making and breaking of chemical bonds, with classical Newtonian mechanics, which captures the movement of proteins.


Ultimately, the ability to computerize such complex chemical processes might make it possible to simulate a complete living organism at the molecular level - something Levitt has described as one of his dreams.


"I am a computer geek," Levitt told Reuters.


Back in the 1960s there were no personal computers, he said, so the only way for scientists to get their hands on a computer was to find ways to use it in their work.


"That's not to say that I became a computational chemist in order to play with computers, but a large part of any creative activity is to feel that you're playing."


"I think if everybody did everything with passion, the world would be a better place," he said.


Chemistry was the third of this year's Nobel prizes. The prizes for achievements in science, literature and peace were first awarded in 1901 in accordance with the will of businessman and dynamite inventor Alfred Nobel.


(Additional reporting by Johan Ahlander and Ben Hirschler in London, Sharon Begley in New York, Richard Valdmanis in Boston, and Alex Dobuzinskis and Dana Feldman in Los Angeles; Editing by Alistair Scrutton, Ralph Boulton and Claudia Parsons)


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Thursday, April 18, 2013

Smoke signals: The intriguing chemistry of a conclave chimney

The eyes of the world are focused on a thin chimney on top of the Sistine Chapel. Underneath, ensconced in the papal conclave, 115 cardinals are due to make their decision as to who will succeed Benedict XVI as Pope. And the answer to the all-important question comes in the form of a simple smoke signal - no tweets or digital communication allowed - but will it be white or black smoke?

So, when the Royal Society of Chemistry was contacted with a question on what goes up the conclave chimney, we turned to our very own holy smoke expert, Reverend Ron Lancaster, former chemistry teacher and founder of Britain's biggest pyrotechnic display company, Kimbolton Fireworks.

As well as explaining some of the chemistry behind smoke production, Revd Lancaster says he's intrigued to know what the Vatican are using to colour the smoke that will herald the new Pope.

"White smokes are easy chemically and often based on zinc chloride from hexachloroethane and zinc oxide. As for making smoke black, we're not sympathetic chemically to making the necessary carbon compounds - the principle of smoke production needs you to burn something, which unfortunately can have nasty environmental side effects.

"The easiest way to create the black colour is to burn a carbon-rich organic material but it disintegrates in the air and tends to turn grey or white quite quickly. In the old days we used anthracine, but that's now thought to be carcinogenic, so they had to stop using that. They then started using naphthalene, which was used in mothballs - it's not damaging to humans but is toxic to fish. Whatever you're burning, someone somewhere doesn't like it!"

Reverend Lancaster spent 25 years as Chaplain and chemistry teacher at Kimbolton School in Cambridgeshire, founding a workshop conducting research into pyrotechnics which led to the creation of his fledgling fireworks company in 1963. He says while white smoke is going to be welcome in Rome this week, it is not always a welcome side-effect for pyrotechnics experts.

"Smoke is often a nuisance to fireworks makers like me as it gets in the way during daylight displays or on a night with no up-draft. And while you can do some incredible things with coloured smoke as a screen, you really want the clearest possible view of the fireworks.

"If I were involved in looking at making smoke at the Vatican, the question I would be asking is what colour it has changed to by the time it gets in air at the top of the chimney - and how many rehearsals they have had.

"Maybe the chimney design is important - I can imagine they must have got hold of some pyrotechnic experts in Italy. But where they did the tests is beyond me!"

Provided by Royal Society of Chemistry search and more info website


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Wednesday, April 10, 2013

First mobile app for green chemistry fosters sustainable manufacturing of medicines

Mention mobile applications, or mobile apps, and people think of games, email, news, weather, productivity and other software for Apple, Android and other smart phones and tablet computers. But an app with broader impact—the first mobile application to foster wider use of the environmentally friendly and sustainable principles of green chemistry—is the topic of a report in the American Chemical Society's new journal, ACS Sustainable Chemistry & Engineering.

Sean Ekins, Alex M. Clark and Antony Williams point out that the companies that manufacture medicines, electronics components and hundreds of other consumer products have a commitment to work in a sustainable fashion without damaging the environment. That's the heart of "green chemistry," often defined as "the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products."

Their article describes a guide on doing so for solvents, key ingredients in processes for making medicines. Some traditional processes generate 25-100 times more waste than the chemical they are making (e.g., pharmaceuticals). The solvents guide was developed by the ACS Green Chemistry Institute's Pharmaceutical Roundtable, a group of 14 pharmaceutical companies. The Green Solvents mobile app version of the guide for Apple devices covers 60 different solvents and is available online at https://itunes.apple.com/us/app/green-solvents/id446670983?mt=8, and the Lab Solvents app for Android devices is available online at https://play.google.com/store/apps/details?id=com.mmi.android.labsolvents.

More information: "Incorporating Green Chemistry Concepts into Mobile Chemistry Applications and Their Potential Uses", ACS Sustainable Chem. Eng., 2013, 1 (1), pp 8–13. DOI: 10.1021/sc3000509

Abstract
Green Chemistry related information is generally proprietary, and papers on the topic are commonly behind pay walls that limit their accessibility. Several new mobile applications (apps) have been recently released for the Apple iOS platform, which incorporate green chemistry concepts. Because of the large number of people who now own a mobile device across all demographics, this population represents a highly novel way to communicate green chemistry, which has not previously been appreciated. We have made the American Chemical Society Green Chemistry Institute (ACS GCI) Pharmaceutical Roundtable Solvent Selection Guide more accessible and have increased its visibility by creating a free mobile app for the Apple iOS platform called Green Solvents. We have also used this content for molecular similarity calculations using additional solvents to predict potential environmental and health categories, which could help in solvent selection. This approach predicted the correct waste or health class for over 60% of solvents when the Tanimoto similarity was >0.5. Additional mobile apps that incorporate green chemistry content or concepts are also described including Open Drug Discovery Teams and Yield101. Making green chemistry information freely available or at very low cost via such apps is a paradigm shift that could be exploited by content providers and scientists to expose their green chemistry ideas to a larger audience.

Provided by American Chemical Society search and more info website


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Smoke signals: The intriguing chemistry of a conclave chimney

The eyes of the world are focused on a thin chimney on top of the Sistine Chapel. Underneath, ensconced in the papal conclave, 115 cardinals are due to make their decision as to who will succeed Benedict XVI as Pope. And the answer to the all-important question comes in the form of a simple smoke signal - no tweets or digital communication allowed - but will it be white or black smoke?

So, when the Royal Society of Chemistry was contacted with a question on what goes up the conclave chimney, we turned to our very own holy smoke expert, Reverend Ron Lancaster, former chemistry teacher and founder of Britain's biggest pyrotechnic display company, Kimbolton Fireworks.

As well as explaining some of the chemistry behind smoke production, Revd Lancaster says he's intrigued to know what the Vatican are using to colour the smoke that will herald the new Pope.

"White smokes are easy chemically and often based on zinc chloride from hexachloroethane and zinc oxide. As for making smoke black, we're not sympathetic chemically to making the necessary carbon compounds - the principle of smoke production needs you to burn something, which unfortunately can have nasty environmental side effects.

"The easiest way to create the black colour is to burn a carbon-rich organic material but it disintegrates in the air and tends to turn grey or white quite quickly. In the old days we used anthracine, but that's now thought to be carcinogenic, so they had to stop using that. They then started using naphthalene, which was used in mothballs - it's not damaging to humans but is toxic to fish. Whatever you're burning, someone somewhere doesn't like it!"

Reverend Lancaster spent 25 years as Chaplain and chemistry teacher at Kimbolton School in Cambridgeshire, founding a workshop conducting research into pyrotechnics which led to the creation of his fledgling fireworks company in 1963. He says while white smoke is going to be welcome in Rome this week, it is not always a welcome side-effect for pyrotechnics experts.

"Smoke is often a nuisance to fireworks makers like me as it gets in the way during daylight displays or on a night with no up-draft. And while you can do some incredible things with coloured smoke as a screen, you really want the clearest possible view of the fireworks.

"If I were involved in looking at making smoke at the Vatican, the question I would be asking is what colour it has changed to by the time it gets in air at the top of the chimney - and how many rehearsals they have had.

"Maybe the chimney design is important - I can imagine they must have got hold of some pyrotechnic experts in Italy. But where they did the tests is beyond me!"

Provided by Royal Society of Chemistry search and more info website


View the original article here

Physical chemistry could answer many questions on fracking

The process of hydraulic fracturing involves drilling a vertical and horizontal well, which can allow the exploration of wide shale formations (up to 6,000 acres) with only a small surface pad (6 acres). Points A, B, C identify the locations for future research opportunities. Credit: Arun Yethiraj and Alberto Striolo, et al. ©2013 American Chemical Society

(Phys.org) —By some estimates, continued growth in hydraulic fracturing (or "fracking"/"fraccing") could put the US on the path to self-sufficiency in energy over the next few decades. Yet despite the potential economic benefits, fracking has also generated controversy due to the unknown long-term consequences of all the drilling, pumping, fracturing, and extracting processes involved. Now, two scientists have identified several important scientific challenges encountered in fracking that can be addressed with physical chemistry, which could lead to improved fracking techniques.

Physical chemists Arun Yethiraj, a professor at the University of Wisconsin-Madison, and Alberto Striolo, an associate professor at the University of Oklahoma in Norman, have published an overview of how physical chemistry could lead to a better understanding of fracking in a guest commentary in The Journal of Physical Chemistry Letters.

Over the past several years, fracking has become more widespread in the US as a relatively cheap way to produce natural gas and oil. The basic process involves drilling into the ground, first vertically and then horizontally; lining this well with a metal casing that contains small holes; and then pumping water (with some additives) into the well at high pressure, which flows through the holes and causes the surrounding rock to crack open. Out of the open cracks in the rock, fluids such as natural gas, oil, and about 10% of the pumped water can flow back to the well and be collected at the surface.

While fracking is currently being used with commercial success, much is still unknown about the details of the process. In 2012, the US National Science Foundation funded a workshop on hydraulic shale fracturing that brought together scientists and engineers from a variety of backgrounds. In the new commentary, Yethiraj and Striolo draw upon the information from this workshop to address the fundamental scientific problems that arise in fracking, and briefly propose how they might be solved with tools from physical chemistry.

"We attempted to outline many physical chemistry questions, to engage the broad community," Striolo told Phys.org. "Every scientist can target a question of his/her personal interest. The impact on the development of the fracking technology, however, is likely to depend on a global systemic approach, where all aspects we pointed out, and others, are tackled together."

For instance, some of the big questions in fracking require a better understanding of the physical properties of fluids in shale, which could be addressed by methods that characterize the shale microstructure and nanostructure, as well as measurements that monitor changes in rock properties upon infiltration of fluids. And since only 10% of the water that was pumped into the well flows back out, where does the rest of it go? If the water is absorbed into the shale, how does it affect the rocks' response to mechanical movement? Experimental data, computer simulations, coarse-grained models, and theoretical studies could help answer these questions.

Other questions include how much natural gas is absorbed by the porous shale, how much natural gas (and other hydrocarbons) is present in source rocks, whether these can be produced, whether fracturing fluids can be designed to reduce the amount of salt and trace metals that are extracted along with the hydrocarbons, how proppants (additives used to "prop" open the fractures) change the flow properties of the hydrocarbons, how back-flow water is treated after it flows back to the surface, how to minimize natural gas and oil leaks at the surface to avoid contaminating aquifers, and many more.

"We believe that proper fundamental investigations and attention in the application of the hydraulic fracturing technology will be able to limit the environmental impact of hydraulic fracturing," Striolo said. "Although accidents can always happen, proper planning and attention to safety and environmental regulations will limit the likelihood of such events."

Essentially every stage of the fracking process poses fundamental questions, but Yethiraj and Striolo think that physical chemists, with collaboration from researchers in other fields, are capable of providing answers.

Both scientists are currently investigating questions that could impact fracking in the future. Yethiraj and his group are developing models for water and aqueous solutions and investigating the static and dynamic properties of water-soluble polymers. Striolo has been investigating the thermodynamic and transport properties of aqueous systems confined in narrow pores. He is also participating in an international initiative (Deep Carbon Observatory https://dco.gl.ciw.edu), whose goal is to better understand the Earth's carbon cycle. The results from these areas of research could help answer some of the questions highlighted in the commentary.

More information: Arun Yethiraj and Alberto Striolo. "Fracking: What Can Physical Chemistry Offer?" The Journal of Physical Chemistry Letters. DOI: 10.1021/jz4000141e

Journal reference: Journal of Physical Chemistry Letters search and more info website

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All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Phys.org.


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New insights into boron's chemistry at room temperature

A ball-and-stick structural model of rhombohedral boron is shown in the foreground and a picture of Badwater Basin in California is shown in the background. The Badwater Basin salt flats contain high concentrations of evaporative minerals such as borax, an important boron-containing compound. Credit: Tadashi Ogitsu; Liam Krauss/Livermore Computing.

(Phys.org) —Livermore researchers have described in detail the properties of the room temperature form of the element boron.

In the periodic table, boron occupies a peculiar, transitional position. It sits on the first row, and has metallic elements to its left, and non-metals to its right. Furthermore, it is the only non-metal in the third column of the periodic table.

It is not surprising that the crystallographic structure and topology of boron's stable form at room temperature (ß-boron) are not shared by any other element, and are extremely complex. The formidable intricacy of ß-boron, characterized by interconnecting icosahedra (a regular polyhedron with 20 identical equilateral triangular faces) partially occupied sites, and an unusually large number of atoms per unit cell (more than 300), has been known for more than 40 years.

Boron chemistry reported in Chemical Reviews The bonding orbitals (red and blue surfaces) in B-boron demonstrate how vacancies and self-interstitials can stabilize the structure. Left: Part of the stable form of boron called the B28 unit (gold ball-and-stick) has a local instability that leads to the introduction of B13 vacancies with unoccupied orbitals (red surfaces). Right: The system is stabilized as two interstitials boronatoms (B17 and B18) are introduced as a pair, which transforms the unoccupied orbitals (red surfaces on the left) to nearly complete chemical bonds (blue surfaces on the right nearby the B17 and B18 interstitials).

Boron remains the only element purified in macroscopic quantities for which the ground state geometry has not been completely determined by experiments. Theoretical progress over the last decade has shed light on numerous properties of elemental boron, leading to a thorough characterization of its structure at ambient conditions, as well as of its electronic and thermodynamic properties.

In the March 8 online edition of Chemical Reviews, LLNL researchers Tadashi Ogitsu and Eric Schwegler along with Giulia Galli of University of California, Davis, discuss in detail starting from the history of boron research, and the properties of ß-boron, as inferred from experiments and the ab-initio theories developed over the last decade.

More information: To read the full research article, go tohere.

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