Tag: Science

When molecules interact with ultraviolet (UV) light, they can change shape quickly, producing strain—stress in a molecule’s chemical structure due to an increase in the molecule’s internal energy. These processes typically take just tens of picoseconds (one millionth of a millionth of a second). Advanced capabilities at X-ray free electron laser (XFEL) facilities now enable scientists to create images of these ultrafast structural changes.

In work appearing in The Journal of Physical Chemistry A, researchers found structural evidence of a strained bicyclic molecule (a molecule consisting of two joined rings) that emerges from the chemical reaction that occurs when a cyclopentadiene molecule absorbs UV light. Cyclopentadiene is a good sample chemical for studying a range of reactions, and these findings have broad implications for chemistry.

Highly strained molecules have a variety of interesting applications in solar energy and pharmaceuticals. However, strain doesn’t typically occur naturally—energy must be added to a molecular system to create the strain. Identifying processes that produce molecules with strained rings is a challenge of broad interest in physical chemistry.

The study confirms a prediction that controlled interactions between light and cyclopentadiene molecules produce strained structures. The team was also able to differentiate between types of ring strain, which could inform future methods for synthesizing molecules.

The team used the Linac Coherent Light Source’s X-ray pulses to study the structural dynamics of cyclopentadiene molecules (i.e., an organic molecule C₅H₆, where the carbon atoms from a symmetric ring), observing the transition to a highly strained state after photoexcitation.

The team excited the molecules with UV light pulses at 243 nanometers and compared time-dependent X-ray scattering data to theoretical models of scattering from different strained molecules that exist during the course of the reaction. The data are consistent with the direct formation of bicylo[2.1.0]pentene, as hypothesized but not directly observed previously.

On the other hand, the experiments did not observe tricyclo[2.1.0.0]pentane, which was also hypothesized as a potential product. These results pave the way toward a greater understanding of how molecular strain plays a role in photoexcited hydrocarbon molecules.

Dr. Byungwook Hwang’s research team from the CCS Research Department at the Korea Institute of Energy Research (KIER) has successfully developed a process that applies the circulating fluidized bed technology, commonly used in coal-fired power plant boilers, to recycle waste plastics and produce pyrolysis oil on a large scale.

Their research is published in the Chemical Engineering Journal.

The COVID-19 pandemic has led to a sharp increase in household plastic waste worldwide. In response, countries around the globe are focusing on recycling technologies, such as pyrolysis, for eco-friendly waste plastic management. Recently, the Korean government announced plans to expand the annual volume of plastic waste processed via pyrolysis from 10,000 tons to 900,000 tons by 2030.

Currently, the kiln method is used in the Republic of Korea for the pyrolysis of waste plastics. This process involves placing waste plastics inside a cylindrical chamber, applying heat externally, and condensing the resulting vapor to produce pyrolysis oil. While the process design is relatively simple, it faces scalability limitations, as heat transfer from the exterior to the center of the cylinder becomes increasingly difficult as the size of the chamber increases.

The kiln method can process only up to 20 tons of plastic per day, which falls far short of the 900,000 tons per year target set by the government for pyrolysis processing. Additionally, the kiln method requires continuous external heat supply and cannot operate continuously, as the process must be paused to handle residual waste before restarting. These limitations make it inefficient for large-scale applications.

The research team developed a technology to recycle waste plastics using a circulating fluidized bed (CFB) process, overcoming the limitations of conventional methods. The CFB process is a technology in which heat carriers, such as high-temperature sand, circulate to enable continuous heat transfer during reactions. For the first time globally, the team successfully applied the CFB process to the pyrolysis of waste plastics, enabling both continuous operation and scalability—key challenges of existing processes.

The core of the developed process lies in heat circulation. In this system, catalyst particles heated in the combustion reactor are circulated to the pyrolysis reactor, where they transfer heat to facilitate the pyrolysis of waste plastics. After transferring heat, the catalyst, now at a lower temperature, returns to the combustion reactor along with the residual waste. The residual waste is incinerated, generating heat to reheat the catalyst. The reheated catalyst is then recirculated back to the pyrolysis reactor, maintaining a continuous process of heat transfer and pyrolysis.

By utilizing this process, a continuous operation is achievable as the cycle of raw material input, heat supply, and residual waste treatment is seamlessly maintained. Additionally, since the catalyst moves freely within the reactor, heat can be effectively transferred from the center to the edges of the reactor, enabling scalability and the development of larger systems.

The research team conducted pyrolysis experiments on waste plastics using their process, handling up to 100 kilograms per day. They confirmed that the process can pyrolyze not only plastics but also solid recovered fuel (SRF) made from household waste. When SRF was processed, the yield was approximately 37%, which is 1.2 times higher than conventional methods. Additionally, the produced pyrolysis oil showed a significant improvement in quality, with a 45% content of light fractions, nearly doubling the quality compared to existing processes.

Dr. Byungwook Hwang, the lead researcher, stated, “The most significant achievement of this study is the design and development of a technology capable of continuously processing waste, including plastic waste, through pyrolysis. This core pyrolysis technology is highly suitable for achieving Korea’s waste plastic pyrolysis targets, as it enables the processing of large volumes of waste plastics while producing high-quality pyrolysis oil.”

In the past, chemicals like asbestos and lead caused widespread harm before their dangers were fully understood. Today, many unknown chemicals similarly pose potential risks. Recently, Chiba University researchers developed a new analysis method for detecting such chemicals in the human body. By studying blood samples from pregnant women, they identified 106 compounds, including potentially harmful substances like phthalates and parabens. This innovative approach could inform new regulations to better protect public health.

From the 1960s to the 1980s, the use of lead in fuel, paints, and pipes caused widespread contamination. It is estimated that 170 million Americans alive today were exposed to high lead levels as children, which caused significant harm, including a measurable drop in IQ scores. While we now understand the dangers of these chemicals, large sections of the population are still exposed to them. UNICEF reports that about 800 million children globally, nearly half of whom live in South Asia, are still exposed to unsafe levels of lead resulting from the hazardous recycling of lead-acid batteries.

Much like the hidden dangers of lead in the past, many of the chemicals we are exposed to today remain poorly understood, along with their potential long-term health effects. To address this issue, researchers at Chiba University in Japan have recently developed an innovative method to detect unrecognized foreign chemicals in the human body. The study was made available online on 26 October 2024 and was published in the journal Ecotoxicology and Environmental Safety. Led by adjunct researcher Dr. Akifumi Eguchi, the study included contributions from Dr. Chisato Mori, Dr. Kenichi Sakurai, and Dr. Midori Yamamoto from the Center for Preventive Medical Sciences at Chiba University.

“There is a growing need for non-targeted chemical analysis to detect new or previously unrecognized substances that are not covered by current targeted analyses,” says Dr. Eguchi, emphasizing the need for broader analytical approaches.

Non-targeted chemical analysis poses significant challenges owing to the large volume of data involved. Additionally, since chemicals exist in various forms, it is necessary to distinguish between endogenous (those naturally produced by the body) and exogenous (those derived from external sources like air, water, or food) chemicals.

To address this, the proposed method uses advanced statistical techniques, including Principal Component Analysis, regularized Generalized Canonical Correlation Analysis, Uniform Manifold Approximation and Projection, and OPTICS clustering. These approaches reduce data complexity and help reveal patterns and groupings among the chemical compounds present in the samples, providing deeper insights into their origins and potential impacts.

Using this method, the researchers analyzed serum samples from 84 pregnant women at 32 weeks of pregnancy. These samples were then examined using Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry.

The detected chemicals were classified based on their origin using the PubChemLite for Exposomics database, which contains information on over 371,663 chemicals. Endogenous chemicals were identified as those naturally produced by the body and associated with biological pathways, while exogenous chemicals were categorized as substances introduced from external sources such as the environment, diet, or lifestyle.

The researchers identified 106 compounds, of which 51 were endogenous and 55 were exogenous. Most of the exogenous chemicals were found to have been introduced into the body through dietary sources. Additionally, they found compounds associated with possible health risks, such as phthalates, nitrogenous compounds, and parabens. Moreover, some of the chemicals identified were found to impact biological pathways, such as amino acid metabolism, protein and mineral transport, and energy metabolism.

While these findings show a link between chemical exposure and its effects on the body, the researchers emphasize that they do not establish a direct cause-and-effect relationship. Since most of the exogenous chemicals were linked to dietary sources, it remains unclear whether the changes in metabolites are due to the substances themselves or the diet. Despite these limitations, the study offers a new method for identifying chemicals and evaluating their potential effects on human health.

“These findings can contribute to public health improvement through the implementation of chemical regulations and related protective measures,” says Dr. Eguchi.

Just as the realization of dangers associated with lead and asbestos led to significant reform and restrictions on these chemicals, the results of this study could help identify new potentially harmful chemicals, paving the way for better regulations to protect human health.

Researchers at University of Tsukuba, Osaka University, and Kitasato University developed a novel amide cyclodextrin (cyclic oligosaccharide) that can selectively capture phosphate ions in water. In addition, the researchers revealed the mechanism by which this cyclic molecule captures phosphate in harmony with water molecules.

This investigation helps elucidate the interaction between water molecules and substances in a water-based environment. It can thus lead to the development of materials that function efficiently in an aqueous environment. The research is published in the journal Chemical Science.

Cyclic molecules are used in a wide range of applications, including molecular sensing, because they can incorporate specific molecules of interest into their inner cavities. Particularly, the ability to precisely recognize and capture specific molecules in water is critical for drug development and environmental analysis.

Cyclic molecules typically employ hydrogen bonding to capture molecules, whereby neighboring molecules are attracted to each other via functional groups bearing hydrogen atoms. However, water molecules present competition for the hydrogen bonding sites, making it challenging to develop cyclic molecules that can recognize target molecules for hydrogen bonding in aqueous systems.

In this project, the researchers developed a new cyclic molecule that achieves precise molecular recognition through hydrogen bonding in harmony with water molecules. Specifically, a novel cyclodextrin (cyclic oligosaccharide) was synthesized with numerous amide groups (-CONH-) that act as hydrogen bonding units. This molecule shows excellent selectivity for target molecules in water, whereby it traps phosphate, but not sulfate or carboxylate species.

The detailed mechanism by which this cyclic molecule selectively traps phosphate species through multi-point hydrogen bonding in harmony with water molecules was elucidated using nuclear magnetic resonance (NMR) spectroscopy, isothermal titration thermometry (ITC), and molecular dynamic (MD) simulations.

The findings of this study provide guidelines to design new cyclic molecules, while elucidating the interaction between water molecules and other substances. Therefore, it is significant for the development of materials that function in an aqueous environment.

What’s the best way to precisely manipulate a material’s properties to the desired state? It may be straining the material’s very atoms, according to a team led by researchers at Penn State. The team discovered that “spray painting” atoms of potassium niobate, a material used in advanced electronics, could tune the resulting thin films with exquisite control.

The finding, published in Advanced Materials, could drive environmentally friendly advancements in consumer electronics, medical devices and quantum computing, the researchers said.

The process, called strain tuning, alters a material’s properties by stretching or compressing its atoms. The researchers use molecular beam epitaxy (MBE), a technique that involves depositing a layer of atoms on a substrate to form a thin film. In this case, they produced a thin film of strain-tuned potassium niobate.

“This was the first time potassium niobate has been grown using MBE,” Gopalan said. “The technique is like spray-painting atoms onto a surface.”

According to the researchers, the novel MBE technique itself creates the strain needed to tune the material.

“This method allows the atoms in the thin films to adjust to the underlying material’s structure, causing strain,” said co-author Sankalpa Hazra, doctoral candidate in materials science and engineering.

“Even a tiny stretch of about 1% can create pressure that would be impossible to achieve by simply pulling or pressing on the material from the outside. This pressure can significantly improve how the material works from a ferroelectric perspective.”

Potassium niobate is ferroelectric, or a class of materials with a natural electric charge that can be reversed by applying an external electric field, much like how magnets have a magnetic field that can be flipped.

“Ferroelectrics are sort of like a mini battery that is already charged up permanently by nature,” said Venkatraman “Venkat” Gopalan, a professor of materials science and engineering at Penn State and corresponding author of the study.

“Despite not being a household name, ferroelectrics are everywhere in key technologies we take for granted in our daily lives. The internet, for example, relies on converting electrical to optical signals, which is performed by a ferroelectric crystal. These materials can reverse their electric polarity when exposed to an external electric field, a quality that also makes them vital for devices like ultrasound equipment, infrared cameras and precision actuators for advanced machinery.”

To “spray paint” the potassium niobate for the study, Gopalan turned to a former Penn State colleague, Darrell Schlom, who is currently the Tisch University Professor in the Department of Materials Science and Engineering at Cornell University. They grew the thin films at the Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM) thin film growth facility, which Schlom co-directs at Cornell. Schlom noted that both he and Gopalan worked at Penn State on the first-ever strain tuning of ferroelectric materials approximately 15 years ago.

“Our role was to help Venkat and Sankalpa realize this material that Venkat has been dreaming about for decades now,” Schlom said. “Venkat made thin films of this material during his doctoral work at Penn State, so he knows just how challenging it can be to grow it. For this work, my student Tobias Schwaigert and I helped them grow this material.”

Schlom explained that strain engineering works by layering two materials of slightly dissimilar sizes. Imagine raining down atoms onto a surface comprising the same type of atoms but spaced a little differently. If the layer being added is thin enough, it will stretch or compress slightly to match the surface below it.

The small change in spacing creates a strain in the material, similar to how a rubber band stretches when pulled. This strain, controlled by the size and spacing of the atoms on the surface, is what leads to changes in the material’s properties, like increasing its temperature limits or improving its ferroelectric performance.

“The superior strength of coupling between strain and polarization in potassium niobate compared to other ferroelectrics allows for a unique opportunity where relatively small amounts of strength can result in colossal tuning of both the ferroelectric structure and polarization of it,” Hazra said.

“A primary consequence of this superior strain sensitivity is that the ferroelectric performance of potassium niobate can be remarkably enhanced even surpassing those of lead titanate or lead zirconate titanate, which are considered to be industrial standard levels of ferroelectricity for device applications.”

Demonstrating the strain tuning of potassium niobate is particularly noteworthy, Hazra said, because potassium niobate is lead-free. While lead raises human toxicity and environmental concerns, the best ferroelectric materials—such as lead titanate and lead zirconate titanate—tend to include lead.

Without strain tuning, potassium niobate’s ferroelectric properties tend not to be as strong as its lead counterparts, but Hazra said the current study shows the potential of potassium niobate as a strong, yet environmentally friendly and safe, ferroelectric material.

According to Hazra, the research team also discovered that strain tuned-potassium niobate’s ferroelectric performance remained stable even at high temperatures. Typically, ferroelectric materials, when heated, lose their polarization—meaning they are no longer able to switch their electrical charge.

“In our work, we’ve shown that applying strain can increase the temperature at which the material loses its ferroelectric properties,” Gopalan said. “What’s even more impressive is that with just a 1% strain, we can push that temperature to over 975 degrees Kelvin, which is close to the point where the material starts to degrade.”

Next, the researchers need to overcome what they called a “serious hurdle” for practical applications: growing these thin films on silicon, which is widely used in the electronics industry. Gopalan’s team is also working on improving the electrical properties of the material by fine-tuning the film growth process. This would enable the use of strain-tuned potassium niobate in practical devices, such as high-temperature memory storage for space exploration, quantum computing and more environmentally friendly high-tech devices.

“With further development, this novel version of the material could become a key player in the next generation of green, high-performance technologies that impact everything from our personal devices to space exploration,” Gopalan said.

The Wadsworth–Emmons (HWE) reaction is a fundamental reaction in organic chemistry, widely used to create conjugated carbonyl compounds. Conjugated carbonyl compounds are used in many industries for synthesizing perfumes, plastics, and pharmaceuticals and are also involved in biological processes. Consequently, methods for improving HWE reactions are an active area of research.

One potential application of HWE reactions is to develop (E)-isomers of conjugated carbonyl compounds that are useful for synthesizing chemicals called hynapene analogs with promising anti-cancer properties. Unfortunately, traditional HWE reaction methods are sometimes inconsistent in their (E)- and (Z)-selectivity and require several steps to get further elongated compounds.

Several studies have investigated new reagents to improve the selectivity of HWE reactions. However, the reason for their enhanced selectivity has not yet been examined enough, nor has the range of substrates suitable for these Weinreb amide-type HWE reagents been fully explored. Additionally, the effect of different reaction conditions on the HWE reaction using the same substrate hasn’t been studied.

In a breakthrough, a research team from the Department of Applied Chemistry at Tokyo University of Science (TUS), Japan, led by Assistant Professor Takatsugu Murata, including Mr. Hisazumi Tsutsui and Professor Isamu Shiina from TUS, conducted a detailed study on HWE reactions and developed a robust and highly (E)-selective Weinreb amide-type HWE reaction with a broad substrate scope.

“The reaction we developed is faster than traditional methods such as the Wittig reaction and the corresponding ester-type HWE reaction, and the applicable compounds can be used in an extremely wide range of applications, including the synthesis of pharmacologically active analogs,” says Murata.

“A key achievement is the isolation of the active species in the reaction, which allows us to efficiently synthesize the important precursor for producing pharmacologically active compounds on a larger scale by preparing the active species in advance.”

Their study is published in The Journal of Organic Chemistry.

In this study, the researchers systematically tested the effect of different bases, solvents, cations, reaction concentrations, and temperatures on the reactivity and selectivity of the Weinreb amide–type HWE reaction.

They discovered that using isopropyl magnesium bromide (ⁱPrMgBr) as a base resulted in high (E)-selectivity, thanks to the formation of a magnesium phosphonoenolate intermediate. The structure of the intermediate and the valence of the metal cation were key to improving selectivity. Moreover, replacing bromine with chlorine in the base further improved selectivity.

Interestingly, the researchers also found that the magnesium phosphonoenolate intermediate formed using the ⁱPrMgCl base was stable enough to be isolated. This isolated intermediate was exceptionally stable, showing no deterioration when stored at room temperature in an argon atmosphere for over six months. This intermediate could be directly used in HWE reaction with high (E)-selectivity.

The team further optimized the amount of ⁱPrMgCl, solvents, and the Weinreb amide–type HWE reagent to maximize the yield of the reaction. The optimized conditions worked well across a wide range of substrates, including various aliphatic saturated aldehydes, aliphatic a, β-unsaturated aldehydes, and aromatic aldehydes, demonstrating the robustness and scalability of the method.

To demonstrate its application, the team applied their novel reaction methodology to synthesize various complex organic compounds, including products from successive elongation processes, the HWE reaction of a cyclic ketone, and Weinreb ketone synthesis.

“Currently, hynapene analogs are being tested in various drug efficacy studies, including animal studies, and their development is highly anticipated, leading to more efficient drug development,” remarks Murata. “We are committed to improving this method further and conducting more studies to gain better insights into the reaction mechanisms.”

The researchers hope that this study offers a pathway towards novel anti-cancer drugs with potential benefits for countless patients.

A group of chemists at the University at Albany have developed a new method for fast-acting salmonella detection. The test employs a paper strip that changes color in the presence of the bacterial genome, enabling quick screening for salmonella in food products.

Unlike other methods, which can take days to yield a result, this system can detect salmonella in under four hours. It is also able to identify and differentiate between two common salmonella strains, and costs less per test than current methods. The work was published in Advanced Healthcare Materials and was featured on the journal’s September cover.

“Salmonella is one of the most common foodborne pathogens, making it a leading concern for food safety worldwide,” said Mehmet Yigit, associate professor in UAlbany’s Department of Chemistry and the RNA Institute, both part of the College of Arts & Sciences.

“Contamination occurs when food comes into contact with animal feces during production, processing or handling. Products like raw or undercooked meat, poultry, eggs, seafood and fresh produce are common sources. Even processed items like peanut butter or frozen meals have been linked to outbreaks.

“In this study, we demonstrate a new method for salmonella detection that uses a novel combination of molecular approaches to signal contamination in a food sample. Designed to be simple, fast and versatile, our method addresses a critical need for quicker, more accessible ways to identify foodborne pathogens.

“Being able to rapidly identify and isolate the source of a pathogen can reduce illness spread, minimize risks to vulnerable populations and reduce disruptions throughout the food supply chain.”

Salmonellosis, the illness caused by ingesting salmonella, can trigger acute gastrointestinal issues and fever. While the illness can resolve without treatment, severe infections can require hospitalization, especially in young children, the elderly or those with weakened immune systems. According to the U.S. Centers for Disease Control and Prevention, about 1.35 million cases of salmonellosis and 420 related deaths occur in this country every year.

For food distributors and restaurants, monitoring for salmonella is both a health imperative and a business priority. Outbreaks are expensive; they can trigger costly product recalls, loss of consumer trust and even legal liabilities, disrupting operations with potential for long-term financial and reputational impacts.

Honing precise and affordable detection

The team’s method uses CRISPR-Cas12a gene editing technology, combined with recombinase polymerase amplification (RPA) and a molecular tool called a “toehold switch” to trigger a visible color change on a paper test strip. In the presence of salmonella, the strip turns red, signaling contamination. If it turns yellow, the sample is clean.

This approach is not only quick and sensitive but also highly specific. The test can detect as few as 100 genome copies of salmonella bacteria and can distinguish between two common serotypes: S. Typhimurium and S. Enteritidis. Identifying the strain type can help track the origin of an outbreak and can dictate the optimal clinical approach to treat an infection.

“A strength of our system is its ability to minimize false-positive results,” Yigit said. “Other approaches involving nanoparticle-based or instrumental techniques often can’t differentiate between pathogens, which reduces practical efficacy in the field.

“Our method also offers cost savings. By using tiny paper disks as the medium for detection, rather than a vial of reaction solution, a much smaller amount of test solution is required to achieve a result. This makes our method about 20 times less expensive per test.”

A portable, adaptable test kit

Unlike traditional methods, this test eliminates the need for extensive laboratory equipment or re-engineering for different bacterial strains, making it possible to implement in a variety of settings, including farms, food processing plants, distribution facilities or restaurants.

“With further development, we aim to transform this technology into a portable, user-friendly kit that can be used widely in the food supply chain,” said lead author Mahera Kachwala, who worked on the project while completing her Ph.D. with Yigit at UAlbany.

“Anyone handling food will be able to easily integrate this test into daily on-site operations, making it possible to stop a salmonella outbreak before it spreads. It could also become a useful tool for restaurant workers and health inspectors, to help ensure that routine hygienic protocols are being employed effectively, and customers are receiving safe, high-quality food.”

The system’s design is also highly adaptable. By changing a single RNA element, it can be programmed to detect other pathogens responsible for food-borne illnesses. For example, the team is exploring ways to use their platform to test for additional types of salmonella, campylobacter and Shiga toxin-producing E. coli (STEC), which together account for millions of hospitalizations and billions in lost food production costs each year.

“Our method demonstrates the power of synthetic biology to create flexible tools for pathogen detection,” Yigit said. “By collaborating with experts in nanotechnology and microbiology, we are excited to bring this innovative technology closer to portable, consumer-ready use.”