. Scientific Frontline: Chemistry
Showing posts with label Chemistry. Show all posts
Showing posts with label Chemistry. Show all posts

Monday, January 23, 2023

A Rainbow of Force-Activated Pigments

A time-elapse video showing how color develops in areas of a specialized polymer that have been placed under strain.
Video Credit: Peter Holderness/Caltech

Stress isn't just the psychological pressure you feel in response to a looming deadline at work. It is also a description of the physical forces pushing, pulling, or twisting an object, structure, or material. Examples of stress include gravity dragging downward on a bridge, wind blowing against the side of a building, or even a waistband drawn taut by a big meal.

With stress affecting literally everything made and used by people, often in damaging ways, it is important to identify when and where it is happening and the extent to which it is occurring. This is not always easy, though, because many materials show no obvious signs of being under stress.

Caltech's Maxwell Robb, an assistant professor of chemistry, has been working to make stress easier to identify through the creation of polymers that change color when a force is applied to them. Now, in a paper published in Nature Chemistry, Robb shows how his team created a new type of these polymers that can be made to change to almost any colors the user wants. This is in contrast to the polymers he had previously developed, which could only change to a single, predetermined color.

Friday, January 20, 2023

RUDN University chemist creates nanocatalysts for vanillin synthesis

Illustration Credit: RUDN University

RUDN University chemist proposed a new method to create catalysts on a porous silicon matrix with metal nanoparticles. Efficient catalysts for organic reactions are obtained, for example, for the synthesis of vanillin, which is in demand in the food and perfume industry.

Only 1% of the annually produced worldwide 20 thousand tons of vanillin is made from natural vanilla. Almost all vanillin in seasonings, pastries, pharmaceuticals and cosmetics is synthesized by chemical protocols. Usually, petrochemical raw materials are used for this, but synthesis from inexpensive plant biomass is also possible. The main ingredient is lignin. This polymer is widely available as it is part of the trees, and it is obtained in the production of paper as a by-product. It is easy to isolate eugenol and other substances suitable for the synthesis of vanillin from lignin, but the next step is challenging. In oxidation reactions, along with vanillin, several by-products similar to it in structure are formed. It is difficult to separate them. The RUDN University chemist proposed a number of eco-friendly nanocatalysts that will allow obtaining more vanillin from plant raw materials than traditional methods.

Algae Can Help Dispose of Hazardous Substances and Produce Bioethanol

Algae can absorb zinc, magnesium, iron, aluminum, silicon and lead.
Photo Credit: Rodion Narudinov

Scientists of the Ural Federal University have developed a technology for the production of environmentally friendly bioethanol fuel using waste heat from thermal power plants (TPP) and combined heat and power plants (CHPP) and freshwater algae produced in large quantities in cooling ponds. The use of this technology leads to a reduction in harmful emissions and makes energy production more efficient. The developers emphasize that the technology signifies a transition from hydrocarbon to green energy. An article describing the technology has been published in the International Journal of Hydrogen Energy.

TPPs and CHPPs are the main suppliers of heat, light, and hot water; at the same time, they are sources of greenhouse gas emissions generated during fuel combustion and saturated with carbon dioxide, soot, unburned particles, and various chemical substances. Another byproduct is the so-called waste heat - water heated during the cooling of superheated steam, rotating turbines of TPPs and CHPPs. The waste heat, in the form of steam, evaporates into the atmosphere in large quantities and is discharged together with industrial effluents into storage ponds. Process water containing solutions of hydrochloric acid, caustic soda, ammonia, ammonium salts, iron and other substances is discharged after flushing the flue gases and boiler units.

Researchers unravel the complex reaction pathways in zero carbon fuel synthesis

Chemical plant
Photo Credit: Robert Jones

When the eCO2EP: A chemical energy storage technology project started in 2018, the objective was to develop ways of converting carbon dioxide emitted as part of industrial processes into useful compounds, a process known as electrochemical CO2 reduction (eCO2R)

While eCO2R is not a new technique, the challenge has always been the inability to control the end products. Now, researchers from the University of Cambridge have outlined how carbon isotopes can be used to trace intermediates during the process, which will allow scientists to create more selective catalysts, control product selectivity, and promote eCO2R as a more promising production method for chemicals and fuels in the low-carbon economy. Their results are reported in the journal Nature Catalysis.

The project was led by Professor Alexei Lapkin, from Cambridge’s Centre for Advanced Research and Education in Singapore (CARES Ltd) and Professor Joel Ager, from the Berkeley Education Alliance for Research in Singapore (BEARS Ltd). Both organizations are part of the Campus for Research Excellence and Technological Enterprise (CREATE) funded by Singapore’s National Research Foundation.

Magnetic method to clean PFAS contaminated water

Researchers at The University of Queensland have pioneered a simple, fast and effective technique to remove PFAS chemicals from water.  

Using a magnet and a reusable absorption aid that they developed, polymer chemist Dr Cheng Zhang and PhD candidate Xiao Tan at the Australian Institute for Bioengineering and Nanotechnology have cleared 95 per cent of per- and polyfluoroalkyl substances (PFAS) from a small amount of contaminated water in under a minute.

“Removing PFAS chemicals from contaminated waters is urgently needed to safeguard public and environmental health,” Dr Zhang said.

“But existing methods require machinery like pumps, take a lot of time and need their own power source.

“Our method shows it is possible to remove more of these chemicals in a way that is faster, cheaper, cleaner, and very simple.

Thursday, January 19, 2023

New, safe, and biodegradable compound blocks radiation

Hesham Zakali: The material developed by an international group of scientists could become an alternative to toxic lead, for example.
Photo Credit: Anastasia Kurshpel

Polylactic acid combined with tungsten trioxide effectively blocks gamma radiation, an international group of scientists including specialists from Russia (Ural Federal University), Saudi Arabia and Egypt has found. In the future, it will be possible to create safe and biodegradable screens for protection against low-energy radiation on the basis of the new material, the researchers believe. Such screens are used in medicine, agriculture and the food industry. A description of the material has been published in the journal Radiation Physics and Chemistry.

"Polylactic acid is a non-toxic polymer of natural origin. It is inexpensive and, importantly, can be broken down by microbes when placed in an industrial plant at high temperatures. Since lactic acid is regularly produced as a byproduct of metabolism in both plants and animals, polylactic acid and its degradation products are non-toxic and safe for the environment," explains Hesham Zakali, co-author of the development and Researcher at the Department of Experimental Physics at UrFU.

Wednesday, January 18, 2023

New ‘chain mail’ material of interlocking molecules is tough, flexible and easy to make

The individual building blocks of a catenane are polyhedral molecules — a type of adamantane — that link arms to form a 2D mesh or 3D network that is sturdy but flexible.
Illustration Credit: Tianqiong Ma, UC Berkeley

University of California, Berkeley, chemists have created a new type of material from millions of identical, interlocking molecules that for the first time allows the synthesis of extensive 2D or 3D structures that are flexible, strong and resilient, like the chain mail that protected medieval knights.

The material, called an infinite catenane, can be synthesized in a single chemical step.

French chemist Jean-Pierre Sauvage shared the 2016 Nobel Prize in Chemistry for synthesizing the first catenane — two linked rings. These structures served as the foundation for making molecular structures capable of moving, which are often referred to as molecular machines.

But the chemical synthesis of catenanes has remained laborious. Adding each additional ring to a catenane requires another round of chemical synthesis. In the 24 years since Sauvage created a two-ring catenane, chemists have achieved, at most, a mere 130 interwoven rings in quantities too small to see without an electron microscope.

Scientists Suggest New Approach to Targeted Treatment of Bacterial Infections

Photo Source: Ural Federal University

It is based on the nanosystem with polyoxometalate

Chemists from the Ural Federal University have proposed a new approach to targeted treatment of affected areas of the human body, in particular, bacterial infections. It is based on a nanosystem, the core of which is polyoxometalate (containing molybdenum and iron). A broad-spectrum antibiotic, tetracycline, is attached to the surface of the polyoxometalate. This approach makes it possible to fight bacteria more effectively by targeting them. The results of the study are published in the journal Inorganics.

"The polyoxometalate ion is a charged nanoparticle that can be used as a base. It is very small - 2.5 nanometers. This allows it to easily penetrate cells and the walls of blood vessels. Drugs and additional substances (vector molecules) can be "planted" on it to help the system reach a specific affected organ. In this case, the drug is distributed less throughout the rest of the body. This reduces side effects, especially of highly toxic drugs," explains Margarita Tonkushina, a Researcher at the Section of Chemical Material Science and the Laboratory of Functional Design of Nanoclusters of Polyoxometalates at UrFU.

Studying Polymer Gels Through the Lens of Mechanochemistry and Solvent Swelling

Multinetwork polymer gels with color-changing linkers sensitive to mechanical stimuli provide a solid platform to study the dynamics of solvent swelling, as shown by researchers from Tokyo Tech. This innovative approach allowed them to gain detailed insight into the mechanical forces that a gel is subjected to when swollen after absorbing a solvent. Their findings will pave the way to developing new, mechanically responsive materials for many applications.

Polymer gels have become a staple technology in various fields, ranging from optics and drug delivery to carbon capture and batteries. However, there are still many open questions about gels and their network structure, which has prevented scientists from linking their remarkable macroscopic properties to specific molecular mechanisms.

One interesting way to tackle this puzzle is to study it from the lens of mechanochemistry; that is, chemical reactions that are triggered by mechanical stimuli such as compression, stretching, and grinding. To make this process easier, scientists can weave mechanophores into polymer networks. These are molecules that undergo predictable chemical changes upon exposure to mechanical stress. While there are many ways to apply mechanical forces to activate mechanophores in a gel, one has been studied in much less detail than others: solvent swelling.

Tuesday, January 17, 2023

New method for designing tiny 3D materials could make fuel cells more efficient

Authors of the study Professor Richard Tilley and Dr Lucy Gloag.
Photo Credit: UNSW Sydney / Courtesy of the researchers 

Researchers have developed an innovative technique for creating nanoscale materials with unique chemical and physical properties.

Scientists from UNSW Sydney have demonstrated a novel technique for creating tiny 3D materials that could eventually make fuel cells like hydrogen batteries cheaper and more sustainable.

In the study published in Science Advances, researchers from the School of Chemistry at UNSW Science show it’s possible to sequentially ‘grow’ interconnected hierarchical structures in 3D at the nanoscale which have unique chemical and physical properties to support energy conversion reactions.

In chemistry, hierarchical structures are configurations of units like molecules within an organization of other units that themselves may be ordered. Similar phenomena can be seen in the natural world, like in flower petals and tree branches. But where these structures have extraordinary potential is at a level beyond the visibility of the human eye – at the nanoscale.

Chemists Created a Substance with Potential Antitumor Activity

The new antitumor substance was synthesized at Ural Federal University's Scientific-educational and Innovation Center of Chemical and Pharmaceutical Technologies.
Photo Credit: Rodion Narudinov

New compound could be the basis of a drug for tumor cells

Chemists from the Ural Federal University and Volgograd State Medical University have created a compound that suppresses cancer cells. The powerful new substance could become the basis for antitumor drugs because it affects the pathology that leads to the development of malignant tumors, such as cancer of the breast, lung, prostate, and lymph nodes. The substance and the results of the experiments were published in the journal Molecules.

"Type 2 casein kinase (CK2) is known to suppress apoptosis in cells, but increased levels of type 2 casein kinase are observed in tumor cells, indicating that these cells are resistant to apoptosis compared to normal cells. If you block this protein, you can achieve tumor cell death. So, our team managed to develop a universal approach to the synthesis of new azolopyrimidines and obtain a library of corresponding heterocycles as potential inhibitors of casein kinase type 2," explains Grigory Urakov, an Engineer of the Scientific Laboratory of Medical Chemistry and Advanced Organic Materials at UrFU.

Monday, January 16, 2023

Speeding up sugar's conversion into fuel

The research has accelerated the production rate and yield of isobutanol from sugar.
Photo Credit: Bishnu Sarangi

University of Queensland researchers have found a way to more efficiently convert sugarcane into a building block of aviation fuel and other products.

By zeroing in on a specific enzyme, a UQ team working in collaboration with the Technical University of Munich (TUM) has sped up the slowest step in processing sugar into a chemical called isobutanol.

Professor Gary Schenk from UQ’s School of Chemistry and Molecular Biosciences said isobutanol from a renewable resource could be used to make fuels, plastics, rubbers and food additives.

“Our research into this particular enzyme means we can accelerate the production rate and yield of isobutanol from sugarcane, ultimately enabling biomanufacturers to make diverse products at scale sustainably and efficiently,” Professor Schenk said.

“Usually during a biomanufacturing process, cells such as yeasts are used as a production platform, but in our research only a small number of a sugar acid-specific dehydratase enzyme was used.

Friday, January 6, 2023

Lithium-sulfur batteries are one step closer to powering the future

Image shows microstructure and elemental mapping (silicon, oxygen and sulfur) of porous sulfur-containing interlayer after 500 charge-discharge cycles in lithium-sulfur cell.
Image Credit: Guiliang Xu/Argonne National Laboratory.

Batteries are everywhere in daily life, from cell phones and smart watches to the increasing number of electric vehicles. Most of these devices use well-known lithium-ion battery technology. And while lithium-ion batteries have come a long way since they were first introduced, they have some familiar drawbacks as well, such as short lifetimes, overheating and supply chain challenges for certain raw materials.

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are researching solutions to these issues by testing new materials in battery construction. One such material is sulfur. Sulfur is extremely abundant and cost effective and can hold more energy than traditional ion-based batteries.

In a new study, researchers advanced sulfur-based battery research by creating a layer within the battery that adds energy storage capacity while nearly eliminating a traditional problem with sulfur batteries that caused corrosion.

UCR scientists develop method to turn plastic waste into potentially valuable soil additive

Recent rain storms washed plastic waste into a creek bed in Riverside's Fairmount Park.
Photo Credit: David Danelski/UCR

University of California, Riverside, scientists have moved a step closer to finding a use for the hundreds of millions of tons of plastic waste produced every year that often winds up clogging streams and rivers and polluting our oceans.

In a recent study, Kandis Leslie Abdul-Aziz, a UCR assistant professor of chemical and environmental engineering, and her colleagues detailed a method to convert plastic waste into a highly porous form of charcoal or char that has a whopping surface area of about 400 square meters per gram of mass.

Such charcoal captures carbon and could potentially be added to soil to improve soil water retention and aeration of farmlands. It could also fertilize the soil as it naturally breaks down. Abdul-Aziz, however, cautioned that more work needs to be done to substantiate the utility of such char in agriculture.

The plastic-to-char process was developed at UC Riverside’s Marlan and Rosemary Bourns College of Engineering. It involved mixing one of two common types of plastic with corn waste — the leftover stalks, leaves, husks, and cobs — collectively known as corn stover. The mix was then cooked with highly compressed hot water, a process known as hydrothermal carbonization.

Monday, December 19, 2022

Daylong wastewater samples yield surprises

Rice University engineers compared wastewater “grabs” to daylong composite samples and found the grab samples were more likely to result in bias in testing for the presence of antibiotic-resistant genes.
 Illustration Credit: Stadler Research Group/Rice University

Testing the contents of a simple sample of wastewater can reveal a lot about what it carries, but fails to tell the whole story, according to Rice University engineers.

Their new study shows that composite samples taken over 24 hours at an urban wastewater plant give a much more accurate representation of the level of antibiotic-resistant genes (ARGs) in the water. According to the Centers for Disease Control and Prevention (CDC), antibiotic resistance is a global health threat responsible for millions of deaths worldwide.

In the process, the researchers discovered that while secondary wastewater treatment significantly reduces the amount of target ARG, chlorine disinfectants often used in later stages of treatment can, in some situations, have a negative impact on water released back into the environment.

The lab of Lauren Stadler at Rice’s George R. Brown School of Engineering reported seeing levels of antibiotic-resistant RNA concentrations 10 times higher in composite samples than what they see in “grabs,” snapshots collected when flow through a wastewater plant is at a minimum.

Scientists from NUS and NUHS identify predictive blood biomarker for cognitive impairment and dementia

Prof Barry Halliwell (left) and Dr Irwin Cheah (right), together with their collaborators from the National University Health System, have discovered that low levels of ergothioneine in blood plasma may predict an increased risk of cognitive impairment and dementia.
Photo Credit: National University of Singapore

Identification of elderly persons at risk of developing cognitive impairment and dementia could be made possible by examining ergothioneine levels in the blood

A recent study by a team comprising researchers from the National University of Singapore (NUS) and the National University Health System (NUHS) revealed that low levels of ergothioneine (ET) in blood plasma may predict an increased risk of cognitive impairment and dementia, suggesting possible therapeutic or early screening measures for cognitive impairment and dementia in the elderly.

The research teams were led by Professor Barry Halliwell from the Department of Biochemistry under the NUS Yong Loo Lin School of Medicine and Associate Professor Christopher Chen and Dr Mitchell Lai from the Memory, Ageing and Cognition Centre under NUHS. The results of their most recent study were published in the scientific journal Antioxidants.

Saturday, December 17, 2022

UCLA-developed soft brain probe could be a boon for depression research

 Illustration of the soft probe with aptamer biosensors implanted in the brain.
Illustration Credit: Zhao, et al., 2022

Anyone familiar with antidepressants like Prozac or Wellbutrin knows that these drugs boost levels of neurotransmitters in the brain like serotonin and dopamine, which are known to play an important role in mood and behavior.

It might come as a surprise, then, that scientists still have very little data about the specific relationship between neurotransmitters — chemicals that relay messages from one brain cell to others — and our psychological states. Simply put, monitoring fluctuations of these neurochemicals in living brains has proved a persistent challenge.

Now, for the first time, UCLA scientists have attached nanoscale biochemical sensors, which are tuned to identify specific neurotransmitters, to a soft, implantable brain probe in order to continuously monitor these chemicals in real time. The new brain probe, described in a paper published in ACS Sensors, would allow scientists to track neurotransmitters in laboratory animals — and, ultimately, humans — during their day-to-day activities.

Friday, December 16, 2022

A poison helps to understand hydrogen-producing biocatalysts

Thomas Happe researches biocatalysts that can produce hydrogen in an environmentally friendly way.
 Photo Credit: RUB, Marquard

The toxic cyanide molecule attacks the enzymes, but also enables new insights into catalysis.

In nature, certain enzymes, so-called hydrogenases, are able to produce molecular hydrogen (H2) to produce. Special types of these biocatalysts, so-called [FeFe] hydrogenases, are extremely efficient and therefore of interest for bio-based hydrogen production. Although science already knows a lot about how these enzymes work, some details have not yet been fully clarified. The photobiotechnology working group at the Ruhr University Bochum around Dr. Jifu Duan and Prof. Dr. Close Thomas Happe. The researchers showed that external cyanide binds to the [FeFe] hydrogenases and inhibits hydrogen formation. They were able to demonstrate a structural change in the proton transport path that helps to understand the coupling of electron and proton transport. They report in the journal Angewandte Chemie.

Thursday, December 15, 2022

Biodegradable medical gowns may add to greenhouse gas

Photo Credit: National Cancer Institute

The use of disposable plasticized medical gowns – both conventional and biodegradable – has surged since the onset of the COVID-19 pandemic. Landfills now brim with them.

Because the biodegradable version decomposes faster than conventional gowns, popular wisdom held that it offers a greener option by less space use and chronic emissions in landfills.

That wisdom may be wrong.

Biodegradable medical gowns actually introduce harsh greenhouse gas discharge problems, according to new research published Dec. 20 in the Journal of Cleaner Production.

“There’s no magic bullet to this problem,” said Fengqi You, the Roxanne E. and Michael J. Zak Professor in Energy Systems Engineering, in the Smith School of Chemical and Biomolecular Engineering.

“Plasticized conventional medical gowns take many years to break down and the biodegradable gowns degrade much faster, but they produce gas emissions faster like added methane and carbon dioxide than regular ones in a landfill,” said You, who is a senior faculty fellow in the Cornell Atkinson Center for Sustainability. “Maybe the conventional gowns is not so bad.”

Scientists Have Figured Out How to Use Silicone to Protect against Radiation

Scientists plan to investigate a broader set of materials that can attenuate radiation.
Photo Credit: Anastasia Farafontova

An international team of scientists has developed a material that can be used in the future as radiation protection against gamma radiation, in particular, it can be used to create radiation protection for Nuclear Power Station workers. The new material is based on silicone using zinc oxide nano powder additions. The results of research on the new material and its properties have been published in the journal Optical Materials. Physicists from Russia (Ural Federal University), Jordan, and Turkey took part in the work.

"Gamma radiation is widespread in the health care, food and aerospace industries. Excessive exposure can be harmful to human health. Gamma radiation is now attenuated or absorbed using lead, concrete, lead-oxide, tungsten, or tin-based materials. These protective materials are not always convenient to use as protection against gamma rays. In addition, they are expensive, too heavy and highly toxic to humans and the environment. This is why it is important to find new materials and optimize their composition for radiation protection, which will ensure human and environmental safety," says Oleg Tashlykov, Associate Professor at the Department of Nuclear Power Plants and Renewable Energy Sources at UrFU.

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