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Friday, 20 January 2017

Chemists create new type of nanomaterial

EVANSTON, US: A team of chemists led by Northwestern University’s William Dichtel has cooked up something big: The scientists have created an entirely new type of nanomaterial and watched it form in real time — a chemistry first.
“Our work sets the stage for researchers interested in studying the fundamental properties of interesting materials and applied systems, such as solar cells, batteries, sensors, paints and drug delivery systems. The findings have enormous implications for how chemists and materials scientists think about nanotechnology and their science in general,” said Dichtel, the Robert Letsinger professor of chemistry at the Weinberg College of Arts and Sciences.
The researchers made covalent organic frameworks (COFs) that are stable — a major development. These strong, stiff polymers with an abundance of tiny pores are suitable for storing all kinds of things, including energy, drugs and other cargo. But what limits COFs from realising these applications is that they are usually prepared as powdery substances that can’t be processed into useful forms.
In this study, the nanoparticles stay suspended in a liquid “ink,” creating a new nanomaterial called a COF colloid. This structure allows the unique materials to be processed into useful forms, such as films of arbitrary size and thickness.
Also, for the first time, the chemists demonstrated that the “cooking,” or heating up, of the ingredients for the nanomaterial can take place inside the imaging tool itself, in this case, a powerful microscope called a transmission electron microscope. With this new technique, Dichtel and his team could study how molecules come together to form COF colloids.
The field of COF is only a decade old, and much needs to be learned about how the porous polymers form and how to keep them stable. Dichtel is a leader in the young field, focused on bringing unprecedented functionality and improved stability to COFs.
The study is published in the journal ACS Central Science. Dichtel is a corresponding author of the study.
The COF colloids are nanoparticles (approximately 50 nanometers in diameter, roughly the size of a virus) made from any number of building blocks in a predictable way. The COF colloids also feature small pores, whose size, shape and chemical groups can be designed precisely. (Each pore is approximately 2.5 nanometers wide, big enough to hold a variety of cargo.)
“This is about as close to useful ‘molecular LEGOs’ as I’ve seen,” Dichtel said. “Being able to keep these materials stable in solution is a major step forward towards taking advantage of their unique combination of properties.”
For the study, Dichtel teamed up with Nathan Gianneschi at the University of California, San Diego, who has developed cutting-edge analysis techniques. Gianneschi, a professor of chemistry and biochemistry, is also a corresponding author of the paper.
Dichtel and Gianneschi developed a new way to watch COF colloids form inside a transmission electron microscope, another major advancement.
The inability to observe reactions as they occur using electron microscopy has been a major limitation, Gianneschi said. Usually, samples have to be dried or frozen to use this technique. The microscopy in this study opens the door to a new dimension: allowing scientists to initiate and observe materials as they form in real time.
“This is something that is routine on the macro scale, of course, but has eluded chemists, biologists and physicists at the nanoscale,” Gianneschi added.
The Camille and Henry Dreyfus Foundation and the US Army Research Office supported the research.
Read More: Chemists create new type of nanomaterial

FMC appoints new director for agricultural solutions, Latin America

PHILADELPHIA, US: FMC Corporation has appointed Ronaldo Pereira as vice president and business director, Latin America for agricultural solutions, and president, FMC Latin America, effective immediately. Pereira most recently served as general manager, Brazil, Agricultural Solutions.
Pereira succeeds Antonio Zem, who retired from FMC after a 38-year distinguished career.
Pereira is uniquely qualified to lead FMC's Latin America business having served extensively in marketing, business development and commercial leadership roles. He joined FMC in 1995 and progressed through a series of market and business development roles in Latin America as well as strategic marketing for FMC's global agricultural business. He also served as Latin America South business director for agricultural solutions and was general manager for Rotam Cropsciences in Brazil. 
Read More: FMC appoints new director for agricultural solutions, Latin America

Quick ceramic-metal processing technology for superior composites

COLLEGE STATION, US: Recent advancements in automotive, aerospace and power generation industries have inspired materials scientists to engineer innovative materials. Ceramic-metal composites or cermets are an example of a new and improved class of materials that can enhance transportation and energy conversion technologies.
Cermets combine useful properties from each of their primary constituent materials such as high-temperature stability of ceramics and machinability and ductility of metals. However, cermets are effective only if their constituent materials do not react with each other during their processing.
Researchers at Texas A&M University have developed a rapid and efficient technology that enables processing ceramics and metals together into cermets with little to no reaction between constituent materials. This breakthrough opens the possibilities for development of new and superior composite materials.
Most ceramics and metals are unstable when combined at high temperatures and are known to react with each other, leaving the final composite materials with undesirable properties such as brittleness or low-temperature resistance.
“This severely limits the number of new composite materials that can be developed for our growing needs,” said Dr Miladin Radovic, associate professor and associate department head in the department of materials science and engineering.
The research is published in the journals Scientific Reports.
Radovic along with Dr Ibrahim Karaman, Chevron Professor I and head of the materials science and engineering department, and former doctoral students Dr Liangfa Hu and Dr Ankush Kothalkar, and Morgan O’Neil, an undergraduate student in the department of mechanical engineering, have developed the current-activated pressure-assisted infiltration (CAPAI) method to combine ceramics and metals resulting in stable, high performance composites.
In only nine seconds, the CAPAI method combines ceramics and metals with little to no reaction between constituent materials. It uses electric current to instantly heat the metal and applied pressure to drive the molten metal into foam made of ceramic.
In their primary study, the researchers selected aluminium for its light weight, corrosion resistance and popularity in automotive and aerospace industries, and ceramic foams of titanium aluminium carbide (Ti2AlC) for their good fracture toughness, electrical and thermal conductivity, and combined them into lightweight cermets with high strength and good temperature stability.
“The electric current and the pressure together provided simultaneous heating and pressure that actively drove the molten metals into the ceramic preform. The fast and controllable heating rate, which was as high as 700 degrees Celsius, offered an easy and efficient way to avoid reactions between ceramics and molten metal,” said Radovic.
The researchers discovered that the resulting composite (Ti3AlC3/Al) was lightweight with competitive mechanical properties at both ambient (room) temperatures and elevated temperatures. It was 10 times stronger at room temperatures and 14 times stronger at 400 degrees Celsius than aluminium alloys and was less prone to severe degradation after exposure to high temperatures.
“Both aluminium and titanium aluminium carbides challenged the conventional methods for producing desirable composite materials because they react to each other at a temperature that is well beyond that needed to combine them in the composite material,” added Radovic. “The CAPAI method allowed processing novel ceramic-metal composites which could not otherwise be obtained using powder metallurgy and conventional infiltration techniques.”
Radovic is optimistic about the limitless opportunities that new and advanced composite materials will offer for both economical and sustainable manufacturing on an industrial scale.
The research was funded by US Air Force Office of Scientific Research, Multidisciplinary Research Program of the University Research Initiative (MURI).
Read More: Quick ceramic-metal processing technology for superior composites

Martin Pugh to retire as COO of Trinseo

BERWYN, US: Trinseo, a global materials company said that Martin Pugh, currently the executive vice president and chief operating officer (COO), will retire, effective 1 March.
The COO position was established as an interim role in 2015 while Trinseo integrated a number of strategic initiatives into the business. The company will not be replacing Pugh in the COO role, as these initiatives have been completed.
Tim Stedman (senior vice president and Business President for basic plastics and feedstocks) and Hayati Yarkadas (senior vice president and business president for performance materials), will now report directly to Chris Pappas, president and CEO of Trinseo.
With a career in the chemical industry spanning nearly 40 years, Pugh has made exceptional contributions to business leadership, marketing management and sales roles around the world. Pugh joined Trinseo (known as Styron at that time) in March 2013 as senior VP and business president for Plastics and later served as SVP and Business President for Performance Materials. During his stay in the company, he held a various leadership position.  
“Martin is a trusted business executive, a respected industry leader, and a friend. In his four years with Trinseo, he has truly made his mark by propelling the company’s evolution and growth to become the successful enterprise it is today. His wisdom, strategic insights and leadership excellence will be missed by Trinseo colleagues and customers alike, and we wish him all the best in his retirement,” said Pappas.
Read More: Martin Pugh to retire as COO of Trinseo

OMC: A new material to trap radioactive elements from water

HOUSTON, US/ KAZAN, RUSSIA: Researchers at Rice University and Kazan Federal University (KFU) in Russia have found a way to extract radioactivity from water and said their discovery could help purify the hundreds of millions of gallons of contaminated water stored after the Fukushima nuclear plant accident.
They stated that their oxidatively modified carbon (OMC) material is low-cost and highly efficient at absorbing radioactive metal cations, including cesium and strontium, toxic elements released into the environment when the Fukushima plant melted down after an earthquake and tsunami in March 2011.
OMC can easily trap common radioactive elements found in water floods from oil extraction, such as uranium, thorium and radium, said Rice chemist James Tour, who led the project with Ayrat Dimiev, a research professor at KFU.
The material makes good use of the porous nature of two specific sources of carbon. One is an inexpensive, coke-derived powder known as C-seal F, used by the oil industry as an additive to drilling fluids. The other is a naturally occurring, a carbon-heavy mineral called shungite found mainly in Russia, Tour said.
The results are published in the journal Carbon.
Treating the carbon particles with oxidising chemicals increased their surface areas and decorated them with the oxygen molecules needed to adsorb the toxic metals. The particles were between 10 and 80 microns wide.
While graphene oxide excelled at removing strontium, the two types of OMC were better at extracting cesium, which he said has been the hardest element to remove from water stored at Fukushima. The OMC was also much easier and less expensive to synthesise and to use in a standard filtration system, he said.
“We know we can use graphene oxide to trap the light radioactive elements of relevance to the Fukushima cleanup, namely cesium and strontium,” Tour said. “But in the second study, we learned we can move from graphene oxide, which remains more expensive and harder to make, to really cheap oxidised coke and related carbons to trap these elements.”
While other materials used for remediation of radioactive waste need to be stored with the waste they capture, carbon presents a distinct advantage. Carbon that has captured the elements can be burned in a nuclear incinerator, leaving only a very small amount of radioactive ash that’s much easier to store,” Tour said.
“Just passing contaminated water through OMC filters will extract the radioactive elements and permit safe discharge to the ocean,” he said. “This could be a major advance for the cleanup effort at Fukushima.”
The two flavours of OMC particles – one from coke-derived carbon and the other from shungite — look like balls of crumpled paper, or roses with highly irregular petals. The researchers tested them by mixing the sorbents with contaminated water as well as through column filtration, a standard process in which fluid is pumped or pulled by gravity through a filter to remove contaminants.
In the mixing test, the labs dispersed nonradioactive isotopes of strontium and cesium in spring water, added OMC and stirred for two hours. After filtering out the sorbent, they measured the particles left in the water.
OMC1 (from coke) proved best at removing both cesium and strontium from contaminated water, getting significantly better as the sorbent was increased. A maximum 800 milligrammes of OMC1 removed about 83 percent of cesium and 68 percent of strontium from 100 millilitres of water, they reported.
OMC2 (from shungite) in the same concentrations adsorbed 70 percent of cesium and 47 percent of strontium.
“Interestingly, plain shungite was used by local people for water purification from ancient times. But we have increased its efficiency many times, as well as revealed the factors behind its effectiveness,” Dimiev said.
In column filtration tests, which involved flowing 1,400 millilitres of contaminated water through an OMC filter in 100-milliliter amounts, the filter removed nearly 93 percent of cesium and 92 percent of strontium in a single pass. The researchers were able to contain and isolate contaminants trapped in the filter material.
Co-authors of the paper are Artur Khannanov, Vadim Nekljudov, Bulat Gareev and Airat Kiiamov, all of the KFU. 
The Russian Government Program of Competitive Growth of KFU supported the research.
Read More: OMC: A new material to trap radioactive elements from water

US Water names current VP as its new CEO

ST MICHAEL, US: US Water Services Inc, a wholly owned subsidiary of Allete Inc has named current senior executive vice president of marketing and strategy, LaMarr Barnes as its new chief executive officer (CEO).
Barnes replaces former CEO Allan Bly, who resigned his position after a 20-year career with the company.
Barnes has more than 25 years of experience in industrial water treatment and technology management. Hired in 2010 as VP of marketing, Barnes assumed added responsibilities as VP of marketing and business development before being named senior executive VP of marketing and strategy in 2015. Barnes is recognised as an expert in plant operations and integrated water treatment program applications.
“I sincerely thank Al Bly for his service to US Water as one of the company’s co-founders and leading our organization as CEO, and wish him the best in his new endeavours,” said Barnes.
“I look forward to assuming the role of CEO and working with our talented employees on continuing customer service excellence and enhancements to our innovative products and services. Our initial focus will be on ensuring an effective transition and maintaining U.S. Water’s growth in an expanding market,” added Barnes.
Bob Adams, incoming Allete chief financial officer and chief risk officer, echoed Barnes’ thanks to Bly, and said he is confident in Barnes’ leadership and knowledge of US Water’s culture and customers.
“We foresee a seamless transition as LaMarr and the U.S. Water leadership team continues to seek growth opportunities by providing sustainable solutions for customers. Allete believes the demand for sustainable water management solutions will increase as large users seek ways to enhance efficiency and improve their bottom line,” concluded Adams.
Read More: US Water names current VP as its new CEO

New method could enhance drug discovery, protein study

LA JOLLA, US: A team led by scientists at The Scripps Research Institute (TSRI) has developed a versatile new method that would enhance the discovery of new drugs and the study of proteins.
The new method empowers researchers to quickly find small molecules that bind to hundreds of thousands of proteins in their native cellular environment. Such molecules, called ligands, can be developed into important tools for studying how proteins work in cells, which may lead to the development of new drugs.
The technique can be used even without prior knowledge of protein targets to discover ligand molecules that disrupt a biological process of interest—and to quickly identify the proteins to which they bind.
“This new platform should be useful not only for discovering new drugs but also for discovering new biology,” said co-lead author Christopher Parker, a research associate in the laboratory of TSRI professor Benjamin Cravatt, chairman of the department of chemical biology.
This research is published in the journal Cell.
Finding new partners for un-targetable proteins
About 25,000 proteins are encoded in the human genome, but public databases list known ligands for only about 10 percent of them. Biologists have long sought better tools for exploring this terra incognita.
The new method involves the development of a set of small, but structurally varied, candidate ligand molecules known as “fragments.” Each candidate ligand is modified with a special chemical compound so that, when it binds with moderate affinity to a protein partner, it can be made to stick permanently to that partner by a brief exposure to UV light. A further modification provides a molecular handle by which scientists can grab and isolate these ligand-protein pairs for analysis.
For a primary demonstration, the team assembled a small “library” of candidate ligands whose structural features include many that are found in existing drugs. By applying just 11 of them to human cells, the researchers identified more than 2,000 distinct proteins that had bound to one or more of the ligands.
These ligand-bound proteins include many from categories—such as transcription factors—that previously had been considered “un-ligandable” and therefore un-targetable with drugs. In fact, only 17 percent of these proteins have known ligands, according to the widely used DrugBank database.
The researchers used further methods to identify, for many ligand-protein interactions, the site on the protein where the coupling occurred.
The candidate ligands initially used to screen for protein binding partners are generally too small to bind to their partners tightly enough to disrupt their functions in cells. But the team showed that, in multiple cases, that these initial small (“fragment”) ligands could be developed into larger, more complex molecules that display higher affinity interactions and disrupt their protein partner’s functions.
A new type of functional screen
For a final demonstration, collaborating chemists at Bristol-Myers Squibb helped create a library of several hundred slightly more complex candidate ligands. With TSRI colleagues associate professor Enrique Saez and co-first author research associate Andrea Galmozzi, the team then tested these ligands to find any that could promote the maturation of fat cells (adipocytes)—a process that in principle can alleviate the insulin resistance that leads to type 2 diabetes.
Traditional functional screens of this type do not pinpoint the proteins or other molecules through which the effect on the cell occurs. But with this new discovery method, the researchers quickly found not only a ligand that strongly promotes adipocyte maturation but also its binding partner, PGRMC2, a protein about which little was known.
“We found a new ‘druggable’ pathway, and we also seem to have uncovered some new biology—despite the fact that adipocyte maturation and other diabetes-related pathways have been studied a lot already,” Parker said.
“With this method, we look forward to exploring much more thoroughly the druggability of human proteins and accelerating investigations of protein biology,” Cravatt added.
Co-authors of the study include TSRI’s Yujia Wang, Kenji Sasaki, Christopher Joslyn and Arthur S. Kim; Bruno Correia of Ecole Polytechnique Federal in Lausanne, Switzerland; and Cullen Cavallaro, Michael Lawrence and Stephen Johnson of Bristol-Myers Squibb.
The work was supported by grants from the National Institutes of Health.
Read More: New method could enhance drug discovery, protein study

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