Browse Articles

A dynamic structural framework for the allosteric regulation of Hsp70 chaperones

A Homobimetallic Frustrated Lewis Pair Cobalt Catalyst for the Methanolysis of Hydrosilanes

Abstract The bimetallic Co(I)/Co(–I) complex [Co(CO) 2 (κ 3 ‐ P , N , P ‐PN H P)][Co(CO) 4 ] ( 1 ) has shown excellent activities in the methanolysis of hydrosilanes, surpassing the related bimetallic Co(I)/Co(–I) complex [Co(CO)(PMe 2 Ph)(κ 3 ‐ P , N , P ‐PN H P)][Co(CO) 4 ] ( 2 ), the Co(II) complex [Co(Cl) 2 (κ 3 ‐ P , N , P ‐PN H P)] ( 3 ), and the Co(I) complex [Co(CO) 2 (κ 3 ‐ P , N , P ‐PN H P)]Cl ( 4 ). A comprehensive DFT study of the plausible reaction mechanisms indicates that the enhanced activity of 1 can be attributed to the presence of the [Co(CO) 4 ] – anion, which enables a frustrated Lewis pair (FLP) mechanism that provides a low energy pathway for the heterolytic splitting of the Si─H bond. The reaction mechanism entails the coordination of the hydrosilane to the Co(I) center upon decoordination of the amine functionality of the PN H P ligand, followed by heterolytic splitting of the Si─H bond with the participation of the Co(I) and Co(–I) centers. Then, the PhSiH 2 group at the Co(–I) center is transferred to the oxygen atom of a methanol molecule, which affords the [H 2 SiPh(HOMe)] + cation, regenerating the [Co(CO) 4 ] – species. [H 2 SiPh(HOMe)] + protonates the hydride at the Co(I) center, leading to the formation of H 2 and the corresponding silyl ether. Alternative reaction pathways, including alternative ionic mechanisms or NH‐assisted bifunctional mechanisms, result in higher activation energies.

Association of CD14 rs2569190 and rs2569191 polymorphisms with tuberculosis susceptibility in the Kurdish population of Iran

Molecular determinants of picornavirus 3C protease binding to phosphoinositide-enriched lipid membranes

Assessment of habitat fragmentation for grey wolf and Persian leopard in some Iranian desert landscapes

Distinct domains of LINGO1 control surface expression and biophysical properties of large conductance Ca2+- and voltage-activated potassium (BK) channels

Genome mining of Streptomyces bambergiensis AC-800 unravels the biosynthetic gene cluster for inhibitors of prolyl hydroxylase fibrostatins

Abstract Streptomyces bambergiensis AC-800 is known as a producer of moenomycin family antibiotics active against gram-positive bacteria. Complete genome sequencing of S. bambergiensis revealed 3 replicons represented by the linear chromosome (7,652,101 bp) and two linear plasmids, pSB1 (418,507 bp) and pSB2 (81,486 bp). Analysis of the chromosome for the presence of secondary metabolite biosynthesis gene clusters (BGCs) revealed 25 BGCs, while other 4 were located on the linear plasmid pSB1. The bioinformatics-based analysis of the moenomycin BGC provided new insights into its biosynthesis. The largest reported polyketide synthase gene cluster spanning over 190 kb was identified on the pSB1 plasmid, with its putative product likely to be represented by a 67-membered glycosylated macrolide related to stambomycins. Co-cultivation of S. bambergiensis AC-800 with a strain of Rhodococcus isolated from a fresh-water bryozoan induced production of a red pigment tentatively identified as fibrostatin. CRISPR-BEST-assisted inactivation of the only PKSIII-encoding gene abolished the production of fibrostatin, allowing the identification of the previously unreported fibrostatin BGC. Subsequent secondary metabolomics of S. bambergiensis cultivated in different media revealed production of both known and presumably novel compounds. This study sets a stage for further investigation of this strain by means of genome mining that may result in the discovery of novel bioactive natural products.

Structural insights into the substrate transport mechanism of the amino acid transporter complex

Temporal transcriptomic dynamics in rat spinal cord after tibial fracture unveil crosstalk between spinal cord and bone

Mechanisms of mitochondrial reactive oxygen species action in bone mesenchymal cells

Antisolvent‐Bathing Strategy with Ultra‐Wide Processing Window for Making High‐efficiency Perovskite Solar Cells in Ambient Air

Abstract Most record‐efficiency perovskite solar cells rely on spin‐coating with antisolvent dripping, which is fundamentally incompatible with roll‐to‐roll (R2R) manufacturing. The crystallization kinetics of dynamic wet film during spin coating differs widely from the static wet film during R2R fabrication, which makes the existing crystallization control strategies become inapplicable while upscaling. The crystallization regulation of static wet film remains a critical challenge, particularly under ambient conditions. In this study, we employed the antisolvent‐bathing method that can efficiently regulate the crystallization process of static wet films made by drop coating. Through systematic investigation of solvent‐antisolvent interdiffusion kinetics and in‐situ crystallization monitoring via time‐resolved UV–Vis spectroscopy, we identify alkyl chlorides (particularly chloroform) as optimal bathing agents. The champion device made by CF bathing achieved an efficiency of 24.49% under ambient conditions (RH 30%–50%), representing the highest efficiency for perovskite solar cells made by the antisolvent bathing method. The device showed negligible decay after 2256 h storage in N 2 atmosphere. The method demonstrates exceptional environmental resilience to humidity and solvent accumulation, accompanied by an ultra‐wide processing window (10 s–10 min bathing duration, >2 min post‐bathing delay tolerance).

Marrying Perona Malik diffusion with Mamba for efficient pediatric echocardiographic left ventricular segmentation

Abstract Segmenting echocardiographic images is a crucial step in assessing heart function, as clinical indicators can be obtained by precisely delineating the left ventricle. The success of subsequent heart analyses depends entirely on the precision of this segmentation. However, echocardiography is characterized by ambiguity and heavy background noise interference, making accurate segmentation more challenging. Present methods lack efficiency and are prone to mistakenly segmenting some background noise areas, such as the left ventricular area, due to noise disturbance. To address these issues, we introduce P-Mamba, which integrates the Mixture of Experts (MoE) concept for efficient pediatric echocardiographic left ventricular segmentation. Specifically, we utilize the recently proposed ViM layers from the vision mamba to enhance our model’s computational and memory efficiency while modeling global dependencies. In the DWT-based (Discrete Wavelet Transform) Perona-Malik Diffusion (PMD) Block, we introduce a block that suppresses noise while preserving the left ventricle’s local shape cues. Consequently, our proposed P-Mamba innovatively combines the PMD’s noise suppression and local feature extraction capabilities with Mamba’s efficient design for global dependency modeling. We conducted segmentation experiments on two pediatric ultrasound datasets and a general ultrasound dataset, namely Echonet-dynamic, and achieved state-of-the-art (SOTA) results. Specifically, on the Pediatric PSAX (8959 images) and Pediatric A4C datasets (6425 images), we achieved Dice scores of 0.922 and 0.906, respectively; on the EchoNet-Dynamic dataset (19882 images), we achieved a Dice score of 0.931. Leveraging the strengths of the P-Mamba block, our model demonstrates superior accuracy and efficiency compared to established models, including vision transformers with quadratic and linear computational complexity.

SMAD1/5-mediated recruitment of the histone demethylase KDM1A controls cell fate programs in embryonic stem cells

Fe─N ₄ ‐Anchored Carbon Layer Patched TiO ₂ Cavities to Construct an “In‐Lattice Heterojunction” for Enhanced Photocatalytic Nitrogen Reduction Reactions

Abstract Efficient charge separation and carrier transfer are critical determinants of the performance of photocatalysts for nitrogen reduction reactions (NRR) which are critical for agricultural and chemical industries. In this study, a novel type of heterostructure, termed an “In‐Lattice heterojunction”, has been constructed by introducing a Fe─N 4 ‐anchored carbon layer (Fe─N─C) onto the surface of defective TiO 2 (D‐TiO 2 ), as well as implanting it into the cavities of D‐TiO 2 . The in‐lattice heterojunction, defined as FNCTO, achieves efficient radial carrier transfer along the Ti─C─N─Fe in‐lattice atomic channel and greatly promoted N 2 adsorption benefiting photocatalytic NRR. Thus, FNCTO exhibits an excellent photocatalytic N 2 reduct`ion into NH 3 activity (88 µmol g −1  h −1 ), obviously higher than that of Fe─N─C sites on noncavity P25, illustrating the crucial role of cavity patch induced in‐lattice heterojunction. This study paves a way for the development of high‐performance Fe─N─C atomic photocatalysts based on noncarbon materials.

Diagnosis of misalignment faults using the DTCWT-RCMFDE and LSSVM algorithms

Reduced complex I activity in the retinal pigment epithelium, but not in rod photoreceptors, affects light signaling without impacting cell survival

Synthesis, photoluminescence properties, solvent effect in molecular structure level, topology, and docking studies on Sulfa drug derivative

ATP hydrolysis-driven structural transitions within the Saccharomyces cerevisiae Rad51 and Dmc1 nucleoprotein filaments

Effect of gastrointestinal digestion on the stability and cytotoxicity of conventional and pegylated liposomes encapsulated with stigmasterol and its esters

Abstract Conventional and PEGylated liposomes encapsulated with stigmasterol and its esters were prepared, and their stability and cytotoxicity during in vitro gastrointestinal digestion were determined. The release of stigmasterol and its oxidation products were analyzed using GC-FID. The cytotoxicity before and after digestion was assessed using human normal small intestinal HIEC-6 cells and colon mucosa CCD 841CoN cells. Both liposome PEGylation and the chemical structure of the encapsulated compounds affect the stability and cytotoxicity of the liposomes after gastrointestinal digestion. Esterification of stigmasterol had an effect on the encapsulation of stigmasterol in liposomes, especially PEGylated liposomes, but the level of fatty acid saturation had no significant influence. PEGylation of liposomes did not inhibit sterol oxidation, but in fact led to the formation of oxidation derivatives. Gastrointestinal digestion increased the cytotoxicity of liposomes with stigmasterol (L-St), but liposomes encapsulated with stigmasterol esters had lower cytotoxicity than did undigested liposomes. PEGylation of liposomes did not cause an increase in cytotoxicity to the small intestinal or colon mucosa cells. However, it should be highlighted that the cytotoxic effects of the digested PEGylated liposomes were considerable higher in colon CCD 841CoN cells than in small intestinal HIEC-6 cells.

Molecular recognition of fungal methylated glucosylceramides by ETD151 defensin