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Category: chemistry – Page 9

Mankind is facing a central challenge: It must manage the transition to a sustainable and carbon dioxide-neutral energy economy.

Hydrogen is considered a promising alternative to fossil fuels. It can be produced from water using electricity. If the electricity comes from , it is called green . But it would be even more sustainable if hydrogen could be produced directly with the energy of sunlight.

In nature, light-driven water splitting takes place during photosynthesis in plants. Plants use a complex molecular apparatus for this, the so-called photosystem II. Mimicking its active center is a promising strategy for realizing the sustainable production of hydrogen. A team led by Professor Frank Würthner at the Institute of Organic Chemistry and the Center for Nanosystems Chemistry at Julius-Maximilians-Universität Würzburg (JMU) is working on this.

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Firefighters show higher rates of glioma-linked SBS42 mutational signatures associated with haloalkane exposure, suggesting occupational risk. The study highlights a clear link between firefighting, chemical exposure, and brain cancer mutations.

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In a megascience-scale collaboration with French researchers from College de France and the University of Montpellier, Skoltech scientists have shown a much-publicized problem with next-generation lithium-ion batteries to have been induced by the very experiments that sought to investigate it. Published in Nature Materials, the team’s findings suggest that the issue of lithium-rich cathode material deterioration should be approached from a different angle, giving hope for more efficient lithium-ion batteries that would store some 30% more energy.

Efficient energy storage is critical for the transition to a low-carbon economy, whether in grid-scale applications, electric vehicles, or portable devices. Lithium-ion batteries remain the best-developed electrochemical storage technology and promise further improvements. In particular, next-generation batteries with so-called lithium-rich cathodes could store about one-third more energy than their state-of-the-art counterparts with cathodes made of lithium nickel manganese cobalt oxide, or NMC.

A key challenge hindering the commercialization of lithium-rich batteries is voltage fade and capacity drop. As the battery is repeatedly charged and discharged in the course of normal use, its cathode material undergoes degradation of unclear nature, causing gradual voltage and capacity loss. The problem is known to be associated with the reduction and oxidation of the in NMC, but the precise nature of this redox process is not understood. This theoretical gap undermines the attempts to overcome voltage fade and bring next-generation batteries to the market.

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Researchers at the University of Turku, Finland, have succeeded in producing sensors from single-wall carbon nanotubes that could enable major advances in health care, such as continuous health monitoring. Single-wall carbon nanotubes are nanomaterial consisting of a single atomic layer of graphene.

A long-standing challenge in developing the material has been that the nanotube manufacturing process produces a mix of conductive and semi-conductive nanotubes which differ in their chirality, i.e., in the way the graphene sheet is rolled to form the cylindrical structure of the nanotube. The electrical and chemical properties of nanotubes are largely dependent on their chirality.

Han Li, Collegium Researcher in materials engineering at the University of Turku, has developed methods to separate nanotubes with different chirality. In the current study, published in Physical Chemistry Chemical Physics, the researchers succeeded in distinguishing between two carbon nanotubes with very similar chirality and identifying their typical electrochemical properties.

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Demand for lithium is rising due to its use in batteries for mobile devices, cars and clean energy storage. Securing access to natural deposits of the mineral is now a matter of strategic importance, but lithium can be found elsewhere in nature.

As an alternative to mining, Imperial researchers have created a technology that could be used to efficiently extract it from saltwater sources such as salt-lake brines or geothermal brine solutions.

Conventional extraction from brines takes months and uses significant amounts of water and chemicals, generating greenhouse gas emissions in the process. The alternative developed by Dr. Qilei Song and his team in the Department of Chemical Engineering uses a membrane that separates lithium from by filtering it through tiny pores.

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A research team led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has discovered “berkelocene,” the first organometallic molecule to be characterized containing the heavy element berkelium.

Organometallic molecules, which consist of a metal ion surrounded by a carbon-based framework, are relatively common for early actinide elements like uranium (atomic number 92) but are scarcely known for later actinides like berkelium (atomic number 97).

“This is the first time that evidence for the formation of a chemical bond between berkelium and carbon has been obtained. The discovery provides new understanding of how berkelium and other actinides behave relative to their peers in the periodic table,” said Stefan Minasian, a scientist in Berkeley Lab’s Chemical Sciences Division and one of four co-corresponding authors of a new study published in the journal Science.

Breakthrough in heavy-element chemistry shatters long-held assumptions about transuranium elements.

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Much of cell behavior is governed by the actions of biomolecular condensates: building block molecules that glom together and scatter apart as needed. Biomolecular condensates constantly shift their phase, sometimes becoming solid, sometimes like little droplets of oil in vinegar, and other phases in between.

Understanding the electrochemical properties of such slippery molecules has been a recent focus for researchers at Washington University in St. Louis.

In research published in Nature Chemistry, Yifan Dai, assistant professor of biomedical engineering at the McKelvey School of Engineering, shares the rules involving the intracellular electrochemical properties that affect movement and chemical activities inside the cell and how that might impact cell processes as a ages. The research can inform the development of treatments for diseases like amyotrophic lateral sclerosis (ALS) or cancer.

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Organolithium compounds, molecules containing a carbon–lithium bond, are excellent precursors for building new carbon–carbon and other carbon–heteroatom bonds. They are widely utilized in both academia and industry for their applications in polymer synthesis, pharmaceuticals, and general organic synthesis.

A conventional method for generating organolithium compounds is done by reacting organohalide compounds, molecules containing a carbon–halogen bond, with lithium metal in an organic solvent. For example, a reaction between 1-bromobutane and lithium metal produces n-butyllithium.

Organolithiums are typically unstable and are therefore rapidly converted into a new product in situ after generating them.

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We evaluated the long-term treatment outcomes and toxicities in patients with clinically localized and locally advanced prostate cancer (PC) who underwent high-dose-rate brachytherapy (HDR-BT) with external beam radiotherapy (EBRT). We retrospectively analyzed 417 patients with PC who underwent HDR-BT with EBRT. The treatment dose was 19-and 13-Gy HDR-BT in two and single fractions, respectively, both combined with external irradiation of 46 Gy in 23 fractions, and hormonal therapy (HT). The median observation period was 7.2 (range, 2.0–17.6) years. The 7-year recurrence-free, PC-specific, and overall survival rates were 93.3%, 99.1%, and 94.8%, respectively, with only six PC mortalities. Multivariable analysis showed that pre-radiotherapy prostate-specific antigen (PSA) of 0.05 ng/mL after neoadjuvant HT was an independent poor prognostic factor of recurrence (HR, 4.44; 95% CI 1.56–12.63; p = 0.005) and overall mortality (HR, 2.20; 95% CI 1.11–4.39; p = 0.025). The 7-year cumulative incidence rate of grade ≥ 2 toxicities in genitourinary and gastrointestinal tracts were 15.7% and 2.0%, respectively. HDR-BT combined with EBRT shows promising disease control and tolerant toxicities for PC. Poor PSA response to neoadjuvant androgen deprivation predicts worse survival measures. These patients may require more intensive multidisciplinary treatment in combination with radiotherapy.

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