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Category: chemistry

Deep-Earth seismic anomalies may be explained by newly discovered manganese compound

Scientists know that manganese, in its various oxide forms, plays a significant role in Earth’s geochemical cycles. However, the exact forms of manganese, their abundance and the mechanisms behind these cycles that occur in Earth’s deep, high-pressure interior are not well understood. But, a recent study, published in Physical Review B, reports on a newly discovered manganese rich compound that might help shed light on manganese’s behavior in Earth’s interior and explain why seismic waves slow down in certain regions.

While Earth’s mantle mostly consists of oxygen, magnesium, silicon, and iron, other elements, like manganese, also play an important role. Manganese oxides, such as MnO, Mn3O4, Mn2O3, MnO2, are known to exist in Earth’s interior and have been studied in the context of their stability in the high-pressure conditions of Earth’s mantle, but researchers think there may be additional manganese oxides involved.

These compounds have the ability to react with other compounds (and oxidize) depending on the surrounding pressure and temperature. They often act as powerful, pressure-sensitive redox agents, actively participating in deep-Earth geochemical cycling by reacting with and oxidizing subducted iron-bearing minerals.

Open-source software unlocks rapid DNA structure generation and analysis in one workflow

Computational chemists at the University of Amsterdam’s Van ‘t Hoff Institute for Molecular Sciences have developed a comprehensive software suite to create accurate models of DNA in biomolecular assemblies. Called MDNA, the user-friendly molecular modeling toolkit helps biochemists, molecular biologists, bioinformaticians, and biophysicists to visualize and analyze DNA structures and perform accurate simulations.

The development of the MDNA suite, led by associate professor Jocelyne Vreede, has been presented in a paper in Nucleic Acids Research.

The software is open-source and publicly available through Figshare and Github. It is easily accessible, providing inspiration to any scientist with an interest in DNA. It has been thoroughly tested by students in mathematics, chemistry and biology, some of whom had hardly any programming experience.

Highly Efficient Perovskite/CIGS Tandem Enabled by Modification of Band Profile of CIGS Bottom Cell

This study examined the potential of narrow-bandgap (Perovskite-based tandem solar cells are a promising photovoltaic (PV) technology to exceed the Shockley–Queisser limit of single-junction solar cells. Perovskite/Si tandem solar cells have been intensively studied, demonstrating a record power conversion efficiency (PCE) of 34.6% [1]. In contrast, the certified record PCE of perovskite/Cu(In, Ga)Se2 (CIGS) tandem solar cells remains 24.6% with a reported efficiency of 24.9% [1, 2]. Theoretical calculations for double-junction tandem solar cells using a detailed balance model indicate that the bandgap (Eg) combinations of 1.12 eV (for a bottom cell) and 1.70 eV (for a top cell) or 0.90 to 1.04 eV (for a bottom cell) and 1.58 to 1.67 eV (for a top cell) can yield a maximum theoretical tandem efficiency [3, 4]. Wide-bandgap perovskite (with Eg equal to or greater than 1.7 eV) has been actively studied for tandem application with Si (Eg = 1.12 eV), the most successful solar cell technology to date as a bottom cell. However, previous studies have shown that wide-bandgap perovskite suffers from substantial open-circuit voltage (VOC) loss due to halide segregation [5], and the maximum PCEs of single-junction perovskite cells have been produced by perovskite with Eg between 1.52 and 1.63 eV [6– 8]. The bandgap of CIGS can be tuned between 1.01 and 1.68 eV by adjusting the Ga/(Ga+In) (GGI) ratio and through tuning of bandgap grading profile [9]. Employing a narrow-bandgap CIGS close to 1.00 eV as a bottom cell is advantageous to use the most efficient, conventional bandgap perovskite as the top cell. Therefore, unlike Si, the bandgap tunability of CIGS offers an opportunity for perovskite/CIGS to attain a greater ultimate performance than perovskite/Si tandem solar cells. Han et al. [10] introduced a thick indium-doped tin oxide (ITO) recombination layer to bury the intrinsic surface roughness of CIGS, followed by chemical mechanical polishing to prepare a smooth surface for the subsequent solution process of perovskite, attaining a certified PCE of 22.4%. Albrecht and coworkers have improved the PCE of perovskite/CIGS tandem solar cells by modifying the hole transport layer (HTL). In their earlier work, a NiOx/PTAA bilayer was utilized to form a uniform HTL on CIGS bottom cells. Recently, a self-assembled monolayer such as 2PACz and Me-4PACz was used, which can enhance the device performance of single-junction perovskite solar cell and its perovskite/CIGS tandem counterpart, achieving a certified PCE of 24.2% [2, 11 – 13].

Most recent studies on perovskite/CIGS tandem solar cells have focused on optimizing the perovskite top cell. In contrast, all CIGS bottom cells include an absorber with a double-graded (DG) bandgap profile optimized around the bandgap of ~1.1 eV. The DG bandgap profile has been adapted primarily for CIGS absorbers prepared by thermal evaporation, which has resulted in high-performing CIGS solar cells with PCEs up to 23.4% [14], and it has proven to be an effective strategy for enhancing performance, optimized for “single-junction” CIGS; however, it has not been determined whether DG would be the ideal configuration for tandem applications. Kim et al. [15] used single-graded (SG) CIGS with a bandgap close to 1.0 eV, where the band grading is only formed on the backside of the absorber. They employed dual alkali post-deposition treatment (PDT) with KF and CsF, demonstrating a CIGS solar cell with a PCE of 20.

AI misses cancer drug target, revealing why lab validation still matters

Researchers at the Icahn School of Medicine at Mount Sinai have identified a previously hidden druggable site in a cancer-related protein that could open the door toward the development of a new generation of more precise cancer drugs. The finding also reveals important limitations in today’s artificial intelligence tools for drug discovery.

The study, published in the June 2 online issue of the Journal of the American Chemical Society, focused on PKMYT1, a type of protein known as a kinase that helps control how cells grow and divide. Because this process can go wrong in cancer, PKMYT1 has emerged as a promising target for new cancer drugs.

Most experimental drugs designed to block kinases work by targeting a region called the ATP-binding site—the part of the protein that uses the cell’s energy supply to function. But many kinases share nearly identical ATP-binding sites, making it difficult for drugs to distinguish between the desired target and other kinases, which can lead to unwanted side effects.

New propulsion system could make tiny satellites both fast and fuel-efficient

MIT engineers are testing a new propulsion system that combines the power and speed of conventional chemical thrusters with the precision and fuel-efficiency of electrical thrusters.

The system could enable the design of nimbler, more flexible small satellites, which could perform both fast, powerful maneuvers and slower, precise adjustments, depending on the mission and moment at hand.

The key to the new system is a special propellant that can power both chemical and electrical thrusters, which traditionally have required separate, bulky fuel sources.

Molecular glasses solve long-standing Arrhenius paradox

Glasses are non-crystalline but solid states of matter in which molecules and atoms are not arranged into a regular crystal lattice, but rather in a disordered pattern. Glassy materials are widely used in various settings, for instance, in the synthesis of pharmaceuticals and the development of electronics or optical devices.

When studying movement and changes in various materials and substances, physicists commonly rely on the so-called Arrhenius model. This is a mathematical framework introduced by Svante Arrhenius in 1889, which can be used to calculate how temperature affects the speed of a heat-activated chemical reaction or physical process.

Past studies have shown that when the Arrhenius model is applied to molecular glasses, it yields unrealistically small pre-exponential factors. Pre-exponential factors are values that describe the intrinsic timescale of the movement of molecules without considering temperature effects.

Proteins can be selectively controlled with radio waves

In a significant advance in biological quantum sensing, a research team led by the Technical University of Munich (TUM) has discovered and tested a new mechanism of action in which proteins can be controlled with radio waves. In doing so, they influence a sensitive quantum state known as spin and make it visible via light. In the future, such findings could help detect and even direct biochemical processes in cells simply from the outside using radio waves.

Until now, quantum sensing has primarily been known from solid-state materials such as diamonds with deliberately introduced tiny defects. The researchers are now transferring this principle to proteins —biological molecules that can be genetically produced and specifically tailored. In the future, this could allow quantum sensors to be built directly into cells or tissue.

These protein-based sensors are potentially particularly well suited for biosensing—that is, for imaging living cells, tissues, or organs. In theory, they sit directly where measurement is needed, making them suitable for studies in organisms—unlike bulky solid-state sensors.

Atomic reshuffle leads to record-breaking catalysts for hydrogen production

Researchers have discovered that atoms can be mixed, separated, and recombined within the same experiment, providing a pathway to a record-breaking catalyst for green hydrogen production. In their study, the team created nanoscale particles containing only a few dozen platinum and nickel atoms and observed unusual dynamic behavior in direct space and in real time. As the two metals separate from one another while maintaining an interface, they become highly active for electrochemical water splitting, leading to efficient hydrogen evolution.

The project was led by the University of Nottingham in collaboration with the University of Birmingham, Diamond Light Source, and Ulm University in Germany. The study appears in Advanced Materials.

Research team leader Dr. Jesum Alves Fernandes, from the School of Chemistry, University of Nottingham, said, “What makes this discovery exciting is that we can reversibly tune the structure of the particle while directly observing the process at the atomic scale. This opens a new strategy for designing adaptive catalysts for a wide range of applications.”

Scientists discover inherited traits that break Mendel’s Laws of genetics

A major mouse study found that some inherited traits are passed down through epigenetic changes that break the classic rules of genetics. Researchers discovered hundreds of cases where these chemical DNA marks behaved unexpectedly, including some that seemed to emerge out of nowhere. They also identified the first known naturally occurring paramutation in a mammal, hinting that environmental influences may play a larger role in inheritance than scientists realized.

John Nash (1928−2015)

John Nash was born on June 13, 1928, in Bluefield, West Virginia, a former coal town nestled deep in the Appalachian Mountains. As a young boy, Nash was solitary, bookish, and introverted. His father, John Sr., was a quiet engineer with an incisive mind. His mother, Virginia, also intelligent, was a former teacher who had large dreams for her son, pushing him to read at four, learn Latin, and skip a grade at school.

The first hint of John Nash’s math talent came in fourth grade, when a teacher told Virginia that the boy couldn’t do the math. Virginia laughed, well aware that her son was going down his own path to solve the simple problems. In high school, John solved his teachers’ clunky proofs in just a few elegant steps. He was one of ten nationally awarded winners of the George Westinghose Award, which provided him with a full scholarship to the Carnegie Institute of Technology. He hopped from engineering to chemistry before discovering his passion: mathematics.

He was accepted into Princeton University, which at the time was to mathematicians what Detroit was, and still is, to cars. Nash first wowed his peers with an elegantly playable board game, which his peers dubbed “Nash,” but later reached the market as Hex. He then absorbed himself in one of the sexiest math fields of the day, game theory, which described strategies in competition, whether in card games or business. His deceptively simple doctoral thesis would later re-orient the field of economics, although no one, not even Nash, predicted its potential.

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