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Category: chemistry – Page 16

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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In anticipation for my next public lecture, the organizer requested the title of my lecture. I suggested: “Hunting for Aliens.” The organizer expressed concern that some members of the audience might confuse me for a U.S. government employee in search of illegal aliens near the southern border wall. I explained that no two-dimensional wall erected on Earth would protect us from extraterrestrials because they will arrive from above. It is just a matter of time until we notice interstellar travelers arriving without a proper visa. A policy of deporting them back to their home exoplanet will be expensive — over a billion dollars per flight. The trip will also take a long time — over a billion years with conventional chemical propulsion. We will have to learn how to live with these aliens, and promote diversity and inclusion in a Galactic context.

The Sun formed in the last third of cosmic history, so we are relatively late to the party of interstellar travelers. Experienced travelers might have been engaged in their interstellar journeys for billions of years. To properly interpret their recorded diaries and photo albums in terms of the specific stars they visited, we would need to accurately interpret their time measurements.

Imagine an interstellar tourist wearing a mechanical analog watch. Such a timepiece is at best accurate to within 3 seconds per day, or equivalently 30,000 years per billion years. This timing error is comparable to the amount of time it takes to hop from one star to another with chemical propulsion. Interstellar travelers must wear better clocks in order to have a reliable record of time.

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A study conducted by researchers from the University of São Paulo sheds light on new discoveries about the mechanisms of oxidative phosphorylation in ATP production. Recent findings highlight the involvement of sodium in mitochondrial respiration.

In an article published in Trends in Biochemical Sciences, Alicia Kowaltowski, a full professor at the University of São Paulo’s Institute of Chemistry (IQ-USP) in Brazil, calls for a “rewriting” of textbooks regarding the location of the electron transport chain in mitochondria and the role of sodium in mitochondrial respiration.

Kowaltowski is also a member of the Research Center for Redox Processes in Biomedicine (Redoxoma), a Research, Innovation, and Dissemination Center (RIDC) funded by FAPESP and based at IQ-USP.

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Scientists have identified an enzyme from soil bacteria that can turn air into electricity. They believe it might be transformed into a renewable power source for small devices.

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The Monash University study, published in the peer-reviewed magazine Nature, demonstrates that the enzyme “Huc” can convert small amounts of hydrogen in the air into an electrical current. An enzyme is a protein that can accelerate chemical reactions in cells.

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Countries worldwide are continuously pursuing green and hygienic technology to generate power from limited natural resources. Power generation from renewable energy sources has reached equality with conventional forms. However, the portability of energy derived from cleaner sources has always been challenging.

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Conventional batteries use elements such as lithium-ion and lead acid, which are toxic, have a serious risk of explosion, and are expensive and harmful to the environment.

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In a new study, EPFL scientists visualized the intricate interplay between electron dynamics and solvent polarization in this process. This is a significant step in understanding a critical process of many chemical phenomena, and it might be the first step to improving energy conversion technologies.

CTTS is like a dance of microbes where one electron from a dissolved material (like salt) emerges and becomes part of the water. This produces a “hydrated” electron, essential for several watery processes, including those necessary for life. Comprehending CTTS is crucial to understanding the motion of electrons in solutions.

In a recent study, EPFL researchers Jinggang Lan, Majed Chergui, and Alfredo Pasquarello examined the complex interactions between electrons and their solvent surroundings. The work was mostly done at EPFL, with Jinggang Lan’s final contributions made while he was a postdoctoral fellow at the Simons Center for Computational Physical Chemistry at New York University.

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Now, a new study combines meteorite data with thermodynamic modeling and determines that the earliest inner solar system planetesimals must have formed in the presence of water, challenging current astrophysical models of the early solar system.

Researchers study iron meteorites as samples from the early solar system. These meteorites represent the metallic cores of the earliest planetesimals that didn’t become planets but orbited the solar system before reaching Earth. By analyzing the chemical compositions of these meteorites, scientists can learn about the conditions in which they formed.

This helps answer questions about whether Earth’s building blocks formed far from the Sun, allowing the existence of water ice, or closer to the Sun, resulting in dry planetesimals. Even though the meteorites don’t contain water, scientists can deduce its past presence by examining its effects on other chemical elements.

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Density functional theory (DFT) is a cornerstone tool of modern physics, chemistry, and engineering used to explore the behavior of electrons. While essential in modeling systems with many electrons, it suffers from a well-known flaw called self-interaction error. A recent study has identified a new area where a correction for this error breaks down.

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The ultrafast dynamics and interactions of electrons in molecules and solids have long remained hidden from direct observation. For some time now, it has been possible to study these quantum-physical processes—for example, during chemical reactions, the conversion of sunlight into electricity in solar cells and elementary processes in quantum computers—in real time with a temporal resolution of a few femtoseconds (quadrillionths of a second) using two-dimensional electronic spectroscopy (2DES).

However, this technique is highly complex. Consequently, it has only been employed by a handful of research groups worldwide to date. Now a German-Italian team led by Prof. Dr. Christoph Lienau from the University of Oldenburg has discovered a way to significantly simplify the experimental implementation of this procedure. “We hope that 2DES will go from being a methodology for experts to a tool that can be widely used,” explains Lienau.

Two doctoral students from Lienau’s Ultrafast Nano-Optics research group, Daniel Timmer and Daniel Lünemann, played a key role in the discovery of the new method. The team has now published a paper in Optica describing the procedure.

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