A Bifunctional Cyclopropeneimine with a Tunable Hydrogen-Bond Donating Group and Its Application in the Enantioselective Synthesis of α,β-Diamino Phosphonates.

Lambert and co-workers have developed several chiral bases using a cyclopropeneimine as the basic moiety. Typically, these catalysts have a pendant hydroxyl group which acts as a hydrogen-bond donor and activates the electrophile. In catalysts with a hydrogen-bond donor, prior work from the Sigman group has shown that the acidity of the donor plays an important role in imparting selectivity.

Mycobacterial MutT1-mediated dephosphorylation of the sensor histidine kinases reveals a new link in the regulation of the two-component signaling.

Bacterial pathogens such as Mycobacterium tuberculosis majorly rely on two-component signaling (TCS) systems to sense and generate adaptive responses to the dynamic and stressful host environment. TCS comprises a sensor histidine kinase (SHK) that perceives the environmental signal and a response regulator (RR) that modulates the target gene expression. TCS occurs via a phosphotransfer event from SHK to RR.

4-Dimethylamino-1,8-Naphthalimide as a Fluorescence Signal Amplification for Site Selective and in Situ Probing of the Hydroxyl Radical.

Overproduction of reactive oxygen species (ROS) is involved in several diseases. Copper can be an efficient catalysts for ROS generation, as it was suggested for Cu bound to aberrant sites. Determination of rates and type of ROS production in more complex biological media is challenging and often only down-stream events can be monitored.

Triplet-to-singlet FRET (TS-FRET) in pure organic phosphors: emerging applications and new opportunities.

Förster resonance energy transfer (FRET) involving spin conversion from the triplet to the singlet state, commonly referred to as triplet-to-singlet FRET (TS-FRET) or phosphorescence energy transfer, has recently emerged as an active area of research in purely organic systems, driven by the development of efficient organic phosphors. This mechanism enables delayed fluorescence with several advantages, including long-lived emission, high quantum yields, large Stokes shifts, and tunable emission profiles, all achieved without the need for complex molecular design strategies. While the growing number of TS-FRET scaffolds has expanded the chemical space of such systems, further progress in this field depends on redirecting the focus toward their practical applications and long-term potential, akin to the well-established singlet-to-singlet FRET systems.

Circularly polarized luminescence-active low molecular weight lanthanide gels: tunable emission including white light.

Circularly polarized luminescence (CPL)-active lanthanide gels are seldom reported, despite their vast potential for various applications. Here, we report CPL-active lanthanide gels with a high dissymmetry factor () and a high quantum yield of 59%. This is the first report of both left- and right-handed CPL-active lanthanide gels by employing simple low molecular weight chiral gelators.

Chemically Boosting Intercalation Voltage and Cycling Stability of Layered Na-Fe-Mn-O Cathode for Na-Ion Batteries through Li/Cu Cosubstitution.

Iron-manganese-based layered Na-ion cathodes are appealing for building low-cost Na-ion batteries. However, their practical realization is hindered by the lower intercalation voltage (<3 V Na/Na) and limited cycle life. To tackle these issues, we utilize Li/Cu-cosubstitution into the O3-Na(FeMn)O cathode to tune the ionocovalency of Fe/Mn-O bonds, which in turn can modulate the electrochemical properties.

Side Chain Driven Mass Spectral Fragmentation of Lys Containing Peptides: C-CO Bond Cleavage in Xxx-Lys-Xxx Sequences.

Mass spectral fragmentation of the tripeptide amide Ala-Lys-Ala-amide (AKA*) yields a product ion at / 228.1, which corresponds to a neutral loss of 43 Da from the ion (/ 271.1).

Programmed cell revival from imminent cell death enhances tissue repair and regeneration.

Cell recovery from near-death states is a critical yet poorly understood aspect of cell biology. Here, we describe a tightly-regulated programmed cell revival process after exposure of cells to cell death-inducing lysosomotropic agents, such as L-leucyl-L-leucine methyl ester (LLOMe). In the initial stage of cell recovery, we observe increased chromatin accessibility and upregulation of genes and pathways associated with embryonic development, regeneration, stemness, and inflammation.

Tuning Phase Stability and Band Gap in Vacancy-Ordered Double Perovskites Rb CsSnI Through Variations in A-Site Cation.

Tetravalent Sn-iodide-based ASnI vacancy-ordered double perovskites have received extensive attention in the recent past. Their phase instabilities, triggered by temperature or compositional changes, offer a pathway to control structure and functional properties. Here, we report the solution synthesis of RbSnI, RbCsSnI, and CsSnI, and their phase transition study using variable temperature powder X-ray diffraction (PXRD).

Neutral genetic diversity during selective sweeps in non-recombining populations.

Selective sweeps, resulting from the spread of beneficial, neutral, or deleterious mutations through a population, shape patterns of genetic variation at linked neutral sites. While many theoretical, computational, and statistical advances have been made in understanding the genomic signatures of selective sweeps in recombining populations, relatively less is understood in populations with little/no recombination, and arbitrary dominance and inbreeding. Using diffusion theory, we obtain the full expression for the expected site frequency spectrum (SFS) at linked neutral sites immediately post and during the fixation of moderately or strongly beneficial mutations.

Device area invariant conductance linearity in scalable silver nanostructure based neuromorphic devices with threshold activation following nociceptive behavior.

Achieving precise control over conductance linearity and low-power switching across different device geometries remains a significant challenge in neuromorphic computing research aiming to mimic efficient in-memory processing. Despite notable advancements, traditional resistive switching elements often face issues such as stochastic switching and non-linear conductance evolution, limiting precision and scalability in neuromorphic applications. This study presents a self-assembled hierarchical Ag nanostructure active material with interdigitated electrode architecture designed to achieve area-invariant conductance linearity and low-voltage threshold switching (∼0.

Fungi as models of centromere innovation: from DNA sequence to 3-dimensional arrangement.

Faithful chromosome segregation is facilitated by the centromeres, specialized genomic loci, which connect chromosomes to microtubules in every cell cycle by recruiting the kinetochore complex. However, a single conserved code does not govern the formation and maintenance of centromeres, as we begin to realize that enormous diversity exists in molecular mechanisms dictating centromere homeostasis across species. The fungal kingdom is a vast resource to study and appreciate the divergent nature of the conserved phenomenon of chromosome segregation.

Decoding Temperature-Dependent Conformer Populations and Dipole Moments in Liquid Ethylene Glycol with Classical and Machine-Learned Potentials.

Delineating the conformer populations in neat liquid ethylene glycol (EG) has been challenging as experiments lack sufficient resolution, while simulations suffer from low accuracy and/or high computational demand. Ab initio MD (AIMD) simulations of liquid EG at ambient conditions have reported that about 20% of the molecules have their central (OCCO) dihedral in the conformation. Yet, adequate conformational sampling is an issue with AIMD simulations, given the limited duration of the trajectory.

Generation of beta actin reporter line (BJNhem20 ACTB-eGFP) in human embryonic stem cells BJNhem20 using CRISPR-Cas9 gene targeting.

Beta actin is a cytoskeletal protein that contributes to a wide range of cellular processes. Here we generated beta actin reporter knock-in in BJNhem20 human embryonic stem cell line by CRISPR Cas9 gene editing. The reporter mEGFP is integrated at the beta actin locus, tagging the N-terminal of the protein via a linker.

Atomic Off-Centering Driven Phonon-Glass Electron-Crystal-like Thermoelectric Transport in Entropy-Stabilized Quinary Telluride.

Entropy engineering offers innovative design opportunities for synthesizing new thermoelectric materials by integrating conflicting physical parameters. Optimization of configurational entropy holds the potential to simultaneously reduce the thermal conductivity through inherent disorder and enhance the Seebeck coefficient by symmetrizing the crystal lattice, both of which are crucial to augmenting the thermoelectric performance of a crystalline solid. Here, we synthesized an entropy-stabilized quinary metal telluride single crystal, AgGeSnSbTe, exhibiting an intriguing phonon-glass electron-crystal (PGEC)-like thermoelectric transport.

Crystallization of Low-Dimensional Lead-Free (R/S-MBA)CuBr Chiral Perovskite Thin Films.

Low-dimensional halide perovskites with chiral organic spacer cations possess unique properties that are appealing for next-generation optoelectronic and spintronic applications. However, a complete understanding and effective control over the thin-film crystallization kinetics of these materials have not yet been established. Here, we unravel a plausible diffusion-controlled crystallization mechanism with spontaneous nucleation for lead-free (R/S-MBA)CuBr thin films by estimating the Avrami exponent, ≈ 0.

In Situ Tracking of Ni-MOF Reconstruction into Active Ni(OH) OER Catalysts.

The oxygen evolution reaction (OER) remains a key bottleneck in electrochemical energy storage and conversion. In this work, we demonstrate the transmutation of a Ni-based metal-organic framework (Ni-MOF), composed of one-dimensional Ni-(μ-OH)/(μ-HO)-Ni chains interconnected by 1,4-ndc linker, into catalytically active β-Ni(OH). This top-down reconstruction strategy involves the disintegration of 1,4-ndc linker and transformation of 1D Ni-(μ-OH)/(μ-HO)-Ni chains (which act as precursors), into ultra-low-dimensional (thickness ∼ 1.

Synergistic Mn-Cr Co-doping in NaV(PO)OF Promising Cathode: Unlocking Superior Performance for Next-Generation Sodium-Ion Batteries.

Sodium vanadium fluorophosphate (NaVO(PO)F, NVOPF), with a NASICON framework, is a promising cathode material due to its robust 3D structure, high operating potential (∼3.8 V), and theoretical energy density (≈494 Wh kg). However, its commercial viability is limited by low electronic conductivity and a reduced practical energy density.

Conduction Band Convergence and Modular Nanostructures: Driving High Thermoelectric Performance in n-Type PbSe.

n-type lead chalcogenides showing high thermoelectric performance are rare due to the larger energy offset between the two lowest energy conduction bands minima, leaving ample opportunity to modulate electronic structure for improving their thermoelectric performance. Here, we present a remarkable thermoelectric figure of merit (zT) of ∼1.8 at 873 K in n-type PbSe doped with MoCl by modulation of the conduction bands, while simultaneously suppressing the phonon transport.

Unraveling Stochastic Dynamics and Switching Mechanism in Ag Network-Based Neuromorphic Device by Impedance Spectroscopy.

Neuromorphic devices are leading advancements in brain-inspired computing. The present study employs impedance spectroscopy on an in-plane volatile neuromorphic device with self-formed silver (Ag) structures to understand its conduction mechanism. Ag islands act as synaptic junctions, while smaller Ag nanoparticles serve as signal transmission channels, mimicking a neural network.

Differential response of neurons to autophagy modulation in Huntington's disease.

Huntington's disease (HD) is caused by the expansion of poly-glutamine repeats in the Huntingtin () gene and is associated with a wide variety of motor and physiological (sleep, metabolism, etc.) perturbations. Studies from diverse model organisms have proposed that modulation of autophagy (a key protein homeostatic pathway) can mitigate the toxic effects of mutant HTT protein.

Resurrection of the Helical Hairpin Hypothesis for Understanding Coronavirus Fusion.

Coronaviruses use the spike protein (spike) to bind to target cells, and fuse the viral envelope with a host lipid membrane. Spike is a large trimeric surface glycoprotein, anchored to the viral membrane (envelope) by a single membrane-spanning polypeptide helix and a short intra-virion domain. In the SARS-CoV-2 virus, the spike is formed by three protomers of 1273 residues, each with two distinct domains separable by enzymatic proteolysis prior to infection.

Multi-channel conduction in electron transport dynamics of three dimensional topological insulators.

Three-dimensional topological insulators (3D TIs) have been the subject of extensive research, primarily emphasizing their surface and bulk properties. Surface state transport is highly sought after due to its spin-momentum locking; however, in real systems, mixing between surface and bulk states often occurs because of defect states present in the bulk band gap. In this study, we provide a detailed electronic characterization of the 3D TI BiSbTeSe(BSTS), which exhibits pronounced surface transport effects.

Pathogenic Features, Experimental Models, and Molecular Tools of Human Fungal Pathogens: Who's on WHO's Radar?

With the prevalence of immunocompromising infections, the emergence of new pathogenic species, rising multidrug resistance, hospital outbreaks, and high mortality rates, once neglected fungal pathogens are now taking over the global healthcare arena, necessitating breakthroughs in diagnostics and therapeutics. The World Health Organization (WHO) recently published a list of critical and high-priority fungal pathogens, underlining the need and significance of broadening the focus to include fungal infections, among other life-threatening infectious diseases. This is also a wake-up call to the scientific community to facilitate a better understanding of the emergence, life cycle, spread, virulence, and drug resistance mechanisms in fungal pathogens.