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Archive for the ‘chemistry’ category: Page 278

Oct 5, 2020

Giant electrochemical actuation in a nanoporous silicon-polypyrrole hybrid material

Posted by in categories: biological, chemistry, computing, cyborgs, sustainability

The absence of piezoelectricity in silicon makes direct electromechanical applications of this mainstream semiconductor impossible. Integrated electrical control of the silicon mechanics, however, would open up new perspectives for on-chip actuorics. Here, we combine wafer-scale nanoporosity in single-crystalline silicon with polymerization of an artificial muscle material inside pore space to synthesize a composite that shows macroscopic electrostrain in aqueous electrolyte. The voltage-strain coupling is three orders of magnitude larger than the best-performing ceramics in terms of piezoelectric actuation. We trace this huge electroactuation to the concerted action of 100 billions of nanopores per square centimeter cross section and to potential-dependent pressures of up to 150 atmospheres at the single-pore scale. The exceptionally small operation voltages (0.4 to 0.9 volts), along with the sustainable and biocompatible base materials, make this hybrid promising for bioactuator applications.

An electrochemical change in the oxidation state of polypyrrole (PPy) can increase or decrease the number of delocalized charges in its polymer backbone (1). Immersed in an electrolyte, this is also accompanied by a reversible counter-ion uptake or expulsion and thus with a marcroscopic contraction or swelling under electrical potential control, making PPy one of the most used artificial muscle materials (15).

Here, we combine this actuator polymer with the three-dimensional (3D) scaffold structure of nanoporous silicon (68) to design, similarly as found in many multiscale biological composites in nature (9), a material with embedded electrochemical actuation that consists of a few light and abundant elemental constituents (i.e., H, C, N, O, Si, and Cl).

Oct 4, 2020

A New Chemical ‘Tree of The Origins of Life’ Reveals Our Possible Molecular Evolution

Posted by in categories: biological, chemistry, evolution

One of the greatest mysteries in our Universe is right here on our own doorstep. No, closer — it’s in every fibre of our being.

At least 3.7 billion years ago, a few simple molecules worked together to create something new. Then a few more. And, somehow, these snowballing combinations eventually produced the first very basic living organisms that would evolve and branch out to become all life on Earth.

Continue reading “A New Chemical ‘Tree of The Origins of Life’ Reveals Our Possible Molecular Evolution” »

Oct 4, 2020

DARPA’s SIGMA Program Transitions to Protect Major U.S. Metropolitan Region

Posted by in categories: biological, biotech/medical, chemistry, terrorism, transportation

On a blustery winter day last December, a car carrying radioactive material approached one of the Port Authority of New York and New Jersey’s major transportation hubs. As the car got closer, an alarm flashed and sounded on a large monitor in the police operations center, identifying on a digital map the exact location of the vehicle and the specific radioactive isotope radiating from the car – Cesium-137. Within minutes, officers in the Port Authority Police Department – equipped with vehicle-mounted and pocket-sized radiation sensors displaying the same real-time digital map – tracked the vehicle and apprehended the suspects in a parking lot. Thankfully, the potential terrorists and radiation-emitting isotope were not a threat, as the scenario was only a drill.

The December exercise marked the capstone for DARPA’s SIGMA program, culminating a five-year effort to develop and deploy an automated, high-performance, networked radiation detection capability for counterterrorism and continuous city-to-region scale radiological and nuclear threat monitoring. The transition of the radiation-detection system took place prior to the coronavirus disease (COVID-19) pandemic. In the eight months since the SIGMA transition, DARPA has been developing and testing additional sensors under its SIGMA+ effort to detect chemical, biological and explosive threats as well.

“We want to thank the Port Authority for their outstanding support throughout the SIGMA program and their continued support as we test SIGMA+ sensors,” said Mark Wrobel, DARPA program manager in the Defense Sciences Office. “Being able to test and refine the system in the country’s largest metropolitan region was invaluable in taking SIGMA from a research project to an operationally deployed system in just five years.”

Oct 3, 2020

The role of solid state chemistry in the development of metal-ion batteries

Posted by in categories: chemistry, particle physics, sustainability

Professors from the Skoltech Center for Energy Science and Technology (CEST), Lomonosov Moscow State University and College de France shared their vision on the importance of solid state chemistry in advancements currently awaited from contemporary and prospective metal-ion batteries. The opinion was contributed as an invited review to Nature Communications.

Metal-ion batteries are the main drivers enabling a smooth transfer to renewables and green energy for a sustainable planet. The artfully designed electrode materials have greatly contributed to the development of high-performance Li-ion batteries that was eventually hallmarked by the 2019 Nobel Prize, which had signified the role solid state chemistry. Targeted design of novel metal-ion battery materials to bring the technology to the next level clearly stands as a great challenge for today’s chemistry community.

The individual properties of atoms and ions encoded in the Periodic Table along with the fundamental trends and principles multiplied by further levels of complexity constitute multitude of possible combinations for scientists to find new battery electrodes. Obviously, the researchers need solid guidelines while searching through this huge parameter space for the best chemical combinations and structures.

Oct 3, 2020

Scientists Made a Super-Enzyme That Absolutely Ravages Plastic Bottles

Posted by in categories: chemistry, food, military, sustainability

The bacteria cocktail eats plastic six times faster than any other bug.


A newly discovered “super-enzyme” could finally mean effective recycling of plastic bottles and other materials, scientists say. The plastic-eating bacteria can digest plastic six times faster than current methods of chemically breaking it down.

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Oct 2, 2020

New nanotechology design provides hope for personalized vaccination for treating cancer

Posted by in categories: biotech/medical, chemistry, nanotechnology

One of the key challenges in developing effective, targeted cancer treatments is the heterogeneity of the cancer cells themselves. This variation makes it difficult for the immune system to recognize, respond to and actively fight against tumors. Now, however, new advances in nanotechnology are making it possible to deliver targeted, personalized “vaccines” to treat cancer.

A new study, published on October 2, 2020 in Science Advances, demonstrates the use of charged nanoscale metal-organic frameworks for generating free radicals using X-rays within tumor tissue to kill directly. Furthermore, the same frameworks can be used for delivering immune signaling molecules known as PAMPs to activate the immune response against . By combining these two approaches into one easily administered “vaccine,” this new technology may provide the key to better local and systemic treatment of difficult-to-treat cancers.

In a collaboration between the Lin Group in the University of Chicago Department of Chemistry and the Weichselbaum Lab at University of Chicago Medicine, the research team combined expertise from inorganic chemistry and to tackle the challenging problem of properly targeting and activating an innate immune response against . This work leveraged the unique properties of nanoscale metal-organic frameworks, or nMOFs —nanoscale structures built of repeating units in a lattice formation that are capable of infiltrating tumors.

Oct 2, 2020

Tunable free-electron X-ray radiation from van der Waals materials

Posted by in categories: biotech/medical, chemistry, engineering, nanotechnology, quantum physics, security

Technion researchers have developed accurate radiation sources that are expected to lead to breakthroughs in medical imaging and other areas. They have developed precise radiation sources that may replace the expensive and cumbersome facilities currently used for such tasks. The suggested apparatus produces controlled radiation with a narrow spectrum that can be tuned with high resolution, at a relatively low energy investment. The findings are likely to lead to breakthroughs in a variety of fields, including the analysis of chemicals and biological materials, medical imaging, X-ray equipment for security screening, and other uses of accurate X-ray sources.

Published in the journal Nature Photonics, the study was led by Professor Ido Kaminer and his master’s student Michael Shentcis as part of a collaboration with several research institutes at the Technion: the Andrew and Erna Viterbi Faculty of Electrical Engineering, the Solid State Institute, the Russell Berrie Nanotechnology Institute (RBNI), and the Helen Diller Center for Quantum Science, Matter and Engineering.

The researchers’ paper shows an experimental observation that provides the first proof-of-concept for theoretical models developed over the last decade in a series of constitutive articles. The first article on the subject also appeared in Nature Photonics. Written by Prof. Kaminer during his postdoc at MIT, under the supervision of Prof. Marin Soljacic and Prof. John Joannopoulos, that paper presented theoretically how two-dimensional materials can create X-rays. According to Prof. Kaminer, “that article marked the beginning of a journey towards sources based on the unique physics of two-dimensional materials and their various combinations—heterostructures. We have built on the theoretical breakthrough from that article to develop a series of follow-up articles, and now, we are excited to announce the first experimental observation on the creation of X-ray radiation from such materials, while precisely controlling the radiation parameters.”

Oct 2, 2020

Novel Role of Microglia as Modulators of Neurons in the Brain Is Discovered

Posted by in categories: chemistry, neuroscience

Researchers have identified a bio-chemical circuit that supports neuron-microglia communication. When neurons are active, they release ATP. Microglia sense extracellular ATP and the compound draws the immune cell toward the neuron.circuit that supports neuron-microglia communication. When neurons are active, they release ATP. Microglia sense extracellular ATP and the compound draws the immune cell toward the neuron.circuit that supports neuron-microglia communication. When neurons are active, they release ATP. Microglia sense extracellular ATP and the compound draws the immune cell toward the neuron.

Sep 29, 2020

Why disordered light-harvesting systems produce ordered outcomes

Posted by in categories: chemistry, energy, nanotechnology, physics

Scientists typically prefer to work with ordered systems. However, a diverse team of physicists and biophysicists from the University of Groningen found that individual light-harvesting nanotubes with disordered molecular structures still transport light energy in the same way. By combining spectroscopy, molecular dynamics simulations and theoretical physics, they discovered how disorder at the molecular level is effectively averaged out at the microscopic scale. The results were published on 28 September in the Journal of the American Chemical Society.

The double-walled light-harvesting nanotubes self-assemble from molecular building blocks. They are inspired by the multi-walled tubular antenna network of photosynthetic bacteria found in nature. The nanotubes absorb and transport light energy, although it was not entirely clear how. “The nanotubes have similar sizes but they are all different at the with the molecules arranged in a disordered way,” explains Maxim Pshenichnikov, Professor of Ultrafast Spectroscopy at the University of Groningen.

Sep 28, 2020

Sediment Discovered in Texas Cave Upends Meteorite Explanation for Global Cooling

Posted by in categories: chemistry, climatology

Researchers say cooling 13,000 years ago is coincident with major volcanic eruption.

Texas researchers from the University of Houston, Baylor University and Texas A&M University have discovered evidence for why the earth cooled dramatically 13,000 years ago, dropping temperatures by about 3 degrees Centigrade.

The evidence is buried in a Central Texas cave, where horizons of sediment have preserved unique geochemical signatures from ancient volcanic eruptions — signatures previously mistaken for extraterrestrial impacts, researchers say.