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Critical mineral constraints pressure energy transition and trade toward the Paris Agreement climate goals
Research on ecological management zoning in Jilin Province based on a human well-being framework
Why do histone monomethylation and dimethylation cause a significant difference in binding to LEDGF?
Lens epithelium-derived growth factor (LEDGF) is a chromatin-binding protein. It regulates gene transcription and is associated with acquired immunodeficiency syndrome and cancer. Its PWWP domain binds to histone H3 at K36 (H3K36). The binding affinity depends on H3K36 methylation. To investigate this dependency, we performed molecular dynamics simulations of the PWWP domain and histone fragments. We found that not only hydrophobic interaction but also electrostatic interaction is important. The binding is not maintained with nonmethylated and monomethylated H3K36 because the tips of these H3K36s form hydrogen bonds with water molecules, while dimethylated and trimethylated H3K36 form no such hydrogen bond, making this binding stable.
Engineering high-density microcrystalline boundary with V-doped RuO2 for high-performance oxygen evolution in acid
Taphonomic bias of hydrothermal silicification in biodiversity patterns of Cambrian shelly pavements from the Iberian Chains, NE Spain
Abstract Silicified fossils are ideal for taxonomic studies because they can be extracted without damage using acids. However, permineralization commonly introduces taphonomic biases: as silica neomorphism occurs, silicified fossils are also susceptible to loss of microstructural fidelity and diagnostic characters useful for taxonomic determination. These processes are studied in the traditional ‘lower‒middle Cambrian’ transition of the Iberian Chains, where the macrofossil content includes variable abundances of trilobites and linguliformean brachiopods. In contrast, acid etching of partly silicified limestone interbeds offers a quite different biodiversity pattern, dominated by trilobite larvae, chancelloriids and sponge spicules, accompanied by locally abundant calcite- and phosphate-walled brachiopods, echinoderm holdfasts, and psammosphaerids and serpulids encrusting disarticulated sclerites. Petrographic, geochemical (chondrite-normalized REE, gull-wing patterns), cathodoluminescence (prominent yellow emission bands between 560 and 580 nm, and weaker blue bands between 440 and 500 nm) and Raman spectral data (main peak at 465.2 cm−1 and secondary ones at 205.5 and 128.1 cm−1) yielded by silicified microfossils reveal that quartz precipitation was induced by a distinct episode of acidic hydrothermal activity, close to 100 °C. The event is linked to a broadly penecontemporaneous tectonic breakdown event, where fissures served as conduits for silica fluids.
Nanoscale surface effects on heterogeneous vapor bubble nucleation
Understanding the mechanisms underlying vapor bubble nucleation on solid surfaces is critical for multiple scientific and engineering applications, such as two-phase thermal management systems and turbomachinery, among others. While classical nucleation theory (CNT) explains how surface wettability influences nucleation by modifying the free energy barrier for smooth surfaces, the interplay between nanoscale surface roughness and wettability for rough surfaces remains less clear. Using molecular dynamics simulations, this study demonstrates that CNT can accurately describe wettability effects on nucleation. In addition, we show how surface cavities can create active nucleation sites without requiring trapped gases. This occurs through spontaneous dewetting of cavities at elevated temperatures, which reduces the nucleation barrier. Our results reveal that cavity-induced nucleation enhancement depends on both wettability and geometry, with dewetting promoting nucleation on lyophobic surfaces and rewetting neutralizing this effect for more lyophilic surfaces. These findings provide insights for designing surfaces to either enhance or suppress bubble nucleation.
Subcellular level spatial transcriptomics with PHOTON
The role of perioperative transfusion in mortality in geriatric patients with intertrochanteric fracture
Two-dimensional electronic spectroscopy of Betaine-30
Betaine-30 is well-established as a standard dye for solvatochromism and has long been studied by ultrafast spectroscopy. Electronic excitation leads to rapid intramolecular electron transfer, while the decay of the resulting state corresponds to back electron transfer to the electronic ground state. Thus, Betaine-30’s photophysics offers a route to probing the role that vibrational excitation and solvent dynamics play in electron transfer reaction rates. Here, we probe the excited state dynamics of Betaine-30 in two solvents (ethanol and acetonitrile) by means of two-dimensional electronic spectroscopy. Population dynamics in ethanol are measured at two pump wavelengths, and global analysis reveals a wavelength dependence of the electron transfer rate. This is assigned to excitation of distinct ground state conformers, which is confirmed by quantum chemical calculations. “Beatmaps” of coherently excited vibrations are recovered and analyzed in terms of the contribution of Raman active modes in ground and excited states. The contribution of modes in the excited state is a strong function of the rate of the electron transfer reaction.
The role of carbon catalyst coatings in the electrochemical water splitting reaction
Abstract Designing inexpensive, sustainable, and high-performance oxygen-evolution reaction (OER) electrocatalysts is one of the largest obstacles hindering the development of new electrolyzers. Carbon-coated metal/metal oxide (nano)particles have been used in such applications, but the role played by the carbon coatings is poorly understood. Here, we use a carbon-coated catalyst comprising metal-oxide nanoparticles encapsulated within single-walled carbon nanotubes (SWNTs), to study the effects of carbon coatings on catalytic performance. Electrolyte access to the encapsulated metal oxides is shut off by plugging the SWNT ends with size-matched fullerenes. Our results reveal that the catalytic activity of the composite rivals that of the metal oxide, despite the fact that the metal oxides cannot access the bulk electrolyte. Moreover, the rate-determining step (RDS) of the OER matches that measured at empty SWNTs, indicating that electrocatalysis occurs on the carbon surface. Synergism between the encapsulated metal oxide and carbon coating was explored using electrochemical Raman spectroscopy and computational analysis, revealing that charge transfer from the carbon host to the metal oxide is key to the high electrocatalytic activity of carbon in this system; decreasing electron density on the carbon surface facilitates binding of – OH, accelerating the rate of the OER on the carbon surface.
Green synthesis of imidazole derivatives in a ternary deep eutectic solvent system
<i>Ab initio</i> simulation of spin-vibronic spectra of methoxy radical
Despite the fact that experimental and theoretical work on the spectrum of methoxy has stretched from the microwave to the ultraviolet and proceeded for nearly 50 years, parts of the spectrum have remained a challenge to simulate theoretically and make reliable line-by-line assignments. The spectral complexity arises because the radical has a non-zero electron spin and significant vibronic coupling between the two electronic components of the ground state due to the presence of a conical intersection. This work describes a completely ab initio effort to understand and assign the spin-vibronic levels of the X̃2E state from 0 to above 3000 cm−1, a region that includes the fundamental transitions of the C–H symmetric and asymmetric stretches that have not previously been identified uniquely. A potential energy surface for methoxy was calculated at the equation-of-motion (EOM)-coupled cluster singles, doubles, and triples (CCSDT)/atomic natural orbital (ANO1) level of theory. Subsequently, this potential energy surface was fit to a quartic power series expansion of all nine vibrational normal coordinates (as determined at the minimum of the conical intersection) by the use of a machine-learning-based algorithm. After the addition of spin–orbit coupling, the spin-vibronic problem was solved using both the Krylov–Schur and Lanczos algorithms with the SOCJT3 software to converge eigenvalues up to 3500 cm−1 and their eigenvectors. The latter were used, in conjunction with the calculated dipole moment and its derivatives (calculated using finite differences at the EOM-CCSDT/ANO1 level), to determine spectral intensities for the spin-vibronic spectra. The calculated transition frequencies and intensities were used to simulate and assign the observed transitions of the spin-vibronic spectra of the radical. The credibility of the assignments and their significance is discussed in detail.
Probing the anomalous Hall transport and magnetic reversal of quasi-two-dimensional antiferromagnet Co1/3NbS2
Liposomal oncolytic adenovirus as a neoadjuvant therapy for triple-negative breast cancer
Abstract Breast cancer remains one of the leading causes of cancer-related death, with triple-negative breast cancer (TNBC) accounting for 15–20% of cases. TNBC, characterized by the absence of ER, PR, and HER2 protein, is an aggressive form of breast cancer that is unresponsive to hormonal therapies and HER2-targeted treatments, with fewer treatment options and poorer prognosis. Oncolytic adenoviruses (Ad) are a potential treatment option for TNBC but require coxsackievirus and adenovirus receptors (CAR) to effectively enter and transduce cancer cells. This study investigates a novel neoadjuvant therapy to improve the efficacy of an oncolytic Ad with human telomerase reverse transcriptase (Ad-hTERT) in CAR-low TNBC tumors using folate surface-modified liposomes to enhance delivery. This therapy helps deescalate treatment by reducing or eliminating the need for checkpoint inhibitors or toxic chemotherapy combinations. In vitro studies using CAR-low TNBC murine 4T1-eGFP cells, CAR-high TNBC human MDA-MB-231-GFP cells and several other TNBC human cancer cell lines with varying CAR expression demonstrated significantly higher cytotoxicity with encapsulated Ad-hTERT compared to Ad-hTERT. Similar results were observed in patient-derived primary TNBC cells. In vivo studies in immunocompetent mice with CAR-low 4T1-eGFP tumors revealed that encapsulated Ad-hTERT, administered as neoadjuvant therapy, resulted in stable or reduced tumor sizes, improved survival rates, higher apoptosis of cancer cells, lower cancer cell proliferation, and increased T-cell infiltration in resected tumors. Furthermore, encapsulated Ad-hTERT prevented lung metastasis and tumor recurrence at the primary site, resulting in higher survival rates in mice. Thus, liposomal encapsulation of Ad may be a viable strategy for treating TNBC.
<i>Ab initio</i> phase diagrams of binary alloys in the low solute concentration limit
Phase diagrams are crucial to the design of new materials, to understand their phase stability and metastability under different thermodynamic conditions, such as composition, temperature, and pressure. Here, we use an ab initio approach to study the phase diagram of a binary alloy within the low concentration limit of a solute. Using the ab initio molecular dynamics calculations based on density functional theory, we estimate the solute partitioning ratios in solid–liquid phase equilibria. The chemical potential difference between the solvent and solute atoms in both solid and liquid phases is calculated using thermodynamic integration. As an illustration of the techniques, we have applied this method to reproduce the phase diagram of the Al–Mg alloy at zero pressure. We also compute the ab initio solid–liquid coexistence curve of pure Al by applying the phase-coexistence method with the free energy correction technique. The calculated results are in close agreement with the experiment, demonstrating the reliability of the models.
Cadherins orchestrate specific patterns of perisomatic inhibition onto distinct pyramidal cell populations
Abstract GABAergic interneurons were thought to regulate excitatory networks by establishing unselective connections onto diverse pyramidal cell populations, but recent studies demonstrate the existence of a cell type-specific inhibitory connectome. How and when interneurons establish precise connectivity patterns among intermingled populations of excitatory neurons remains enigmatic. We explore the molecular mechanisms orchestrating the emergence of cell type-specific inhibition in the mouse cerebral cortex. We demonstrate that layer 5 intra- (L5 IT) and extra-telencephalic (L5 ET) neurons express unique transcriptional programs, allowing them to shape parvalbumin- (PV+) and cholecystokinin-positive (CCK+) interneuron wiring. We identified Cdh12 and Cdh13 , two cadherin superfamily members, as underpinnings of cell type- and input-specific inhibitory patterns of L5 pyramidal cell populations. Multiplex monosynaptic tracing revealed a minimal overlap between IT and ET presynaptic inhibitory networks and suggests that different PV+ basket cell populations innervate distinct L5 pyramidal cell types. Here, we unravel the contribution of cadherins in shaping cell-type-specific cortical interneuron wiring.
Ringxiety and internet addiction as factors affecting medical students’ behaviour during clinical rotations
You reap what you sow: On the impact of nuclei morphology on seeded molecular dynamics simulations
Seeded molecular dynamics represents an increasingly popular approach to investigate crystal nucleation via computer simulations. This method involves the insertion of crystalline seeds into the supercooled liquid phase (often over a range of temperatures or sizes) in order to measure their evolution in time. When dealing with the prototypical scenario of crystal nucleation from Lennard-Jones melts, these seeds are artificially constructed to be approximately spherical fcc nuclei. In addition, the order parameter used to monitor the time evolution of a seed is typically chosen as the number of crystal-like atoms within it—consistent with the tenets of classical nucleation theory. However, evidence suggests that these artificially constructed seeds might be rather different from the crystalline nuclei formed during unbiased molecular dynamics simulations. In particular, previous studies of Lennard-Jones crystallization indicate that non-spherical, as well as bcc, nuclei might be involved with the nucleation process. In this work, we assess the impact of the choice of the initial crystalline nuclei in the context of seeded molecular dynamics by directly comparing two different classes of seeds. Specifically, we consider either crystalline nuclei extracted from “brute force” nucleation trajectories (“unbiased seed”) or artificially constructed fcc spherical nuclei (“constructed seeds”). We show that the properties of these two classes of seeds, most notably their committor probability distributions, are markedly different. We also discuss the importance of choosing an appropriate order parameter for seeded molecular dynamics simulations and the implications of our results in the context of estimating crystal nucleation rates via computer simulations.