Browse Articles

A leucine responsive small RNA AbcR200 regulates expression of the lactate utilization (lut) operon in Acinetobacter baumannii DS002

Electric field-induced depolarization of direct current and alternating current poled PMN-PT single crystals

Understanding the depolarization of ferroelectric materials caused by external stimuli is critical for maintaining the aligned polarization states. Although thermal depolarization in poled materials is well established, the mechanisms of electric field-induced depolarization remain largely unexplored. In this study, we investigate the electrical depoling behavior of [001]-oriented rhombohedral Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals poled using direct current poling (DCP) and alternating current poling (ACP). We reveal that the ACP sample exhibits a lower reverse coercive field than the DCP specimen. We compare the effects of bipolar and unipolar electric fields applied in the reverse poling direction, analyzing the changes in permittivity and piezoelectric resonance. Piezoresponse force microscopy is employed to characterize domain configurations in poled and electrically depoled samples. Our findings suggest that property degradation may arise from the nucleation and growth of domains oriented opposite to the initial arrangement.

A fucose-binding superlectin from Enterobacter cloacae with high Lewis and ABO blood group antigen specificity

Toward flexible intensity control of resonantly scattered <b> <i>γ</i> </b>-rays using multi-frequency vibrating resonant absorber

We report a method for coherent control of γ-photons, enabling the shaping of γ-ray intensity in nearly arbitrary waveforms. Different intensity waveforms are created by adjusting the motion profile of a resonant absorber (an ensemble of Mössbauer nuclei) and tuning the energy of the incident radiation. A crucial aspect of this method is the use of a low fundamental frequency of vibrations, which broadens the possibilities for γ-ray control. The results of numerical simulations are experimentally validated by generating single and double γ-pulses and inducing short-term absorption. For this, a resonant absorber containing 57Fe nuclei was vibrated with different motion profiles composed of 12 harmonics with a fundamental frequency of 1 MHz. The proposed technique represents an advancement in the manipulation of γ-rays, and potentially x rays, paving the way for the performance of unique types of γ-ray or x-ray quantum experiments and the development of tools such as adjustable table-top γ-pulse sources or γ-ray or x-ray delays and gates. Moreover, inverse application of the method enables investigation of motion at the picometer scale.

ECM stiffness regulates lung fibroblast survival through RasGRF1-dependent signaling

Effect of electronic state for in-materio physical reservoir computing performance with a porphyrin-polyoxometalate/single-walled carbon nanotube network

Semiconducting single-walled carbon nanotube (SWNT)/porphyrin-polyoxometalate (por-POM) networks were fabricated using [H4tBuTPP]2[SV2W10O40] (tBu H4TPP-POM) and [H4TPP]2[SV2W10O40] (H4TPP-POM) to compare their reservoir computing (RC) performances. Nonlinear electrical properties, phase shifts, and higher harmonics, which are required for superior RC performances, were generated in SWNT/por-POM networks. Lissajous plots show various phase shifts as the input frequency decreases, reflecting the relaxation time of the dynamics in the por-POMs. The SWNT/H4TPP-POM network exhibits the best performance of the RC benchmark task, indicating that H4TPP-POM generates rich chemical dynamics based on different charge accumulation with different electronic state in por-POM.

The “Ins and Outs and What-Abouts” of H2A.Z: A tribute to C. David Allis

One-step fabrication of sharp platinum/iridium tips via amplitude-modulated alternating-current electropolishing

The platinum/iridium (Pt/Ir) alloy tip for scanning probe microscopy was fabricated by amplitude-modulated alternating-current electropolishing. The clean tips with a radius of curvature less than 100 nm were reproducibly obtained by applying the sinusoidal voltage in the frequency (f0) of 900 Hz≤f0≤1500 Hz with amplitude modulation by the sinusoidal wave in the modulation frequency (fs) of fs=0.1f0 in CaCl2/H2O/acetone solution. The analyses by scanning electron microscopy with an energy-dispersive x-ray analyzer and atom probe tomography showed that a uniform Pt/Ir alloy was exposed on the tip surface as a clean surface without O or Cl contamination. The scanning tunneling microscopy (STM) imaging using the fabricated tip showed that it is more suitable for investigating rough surfaces than conventional as-cut tips and applicable for atomic-resolution imaging. Furthermore, we applied the fabricated tip to qPlus atomic force microscopy (AFM) analysis in liquid and showed that it has atomic resolution in both the horizontal and vertical directions. Therefore, it is concluded that the amplitude-modulated AC etching method reproducibly provides sharp STM/AFM tips capable of both atomic resolution and large-area analyses without complex etching setups.

Evolutionary scenarios for the specific recognition of nonhomologous endogenous peptides by G protein–coupled receptor paralogs

Signal-noise analysis of miniaturized delta-E effect magnetic field sensors

Delta-E effect sensors developed for detecting small amplitude and low-frequency magnetic fields have shown potential for miniaturization. However, a comprehensive signal-and-noise analysis of such miniaturized sensors is lacking. Here, we present an in-depth study of the key performance characteristics of sub-millimeter-sized delta-E effect sensors with a double-wing resonator geometry. Several resonance modes are evaluated for their sensitivity, noise, and limit of detection (LoD) as functions of the excitation voltage amplitude and magnetic bias flux density. We identify and discuss the optimal conditions for sensor operation and compare the performance to that of the reported macroscopic devices. While all investigated resonance modes behave qualitatively similar, quantitative differences in signal and noise lead to an almost sevenfold difference in LoD s. The performance is limited by magnetic noise at large excitation amplitudes and, unlike reported macroscopic delta-E effect sensors, by noise from the excitation signal and charge amplifier at low excitation amplitudes. The best performance is achieved in the third resonance mode excited at 683 kHz with a LoD≤7.4±3 nT/Hz between 10 and 1000 Hz and a minimum of 2.8 nT/Hz at 195 Hz. This demonstrates an improvement over previously reported values for miniaturized delta-E effect sensors in this frequency range. Moreover, the sensors show a −3 dB bandwidth of ≈440 Hz, which is significantly wider compared to macroscopic delta-E effect sensors. Reducing electronic noise and employing advanced magnetic multilayers can further improve the LoD, making these miniaturized sensors promising candidates for compact arrays.

The RecA-NT homology motif in ImuB mediates the interaction with ImuA′, which is essential for DNA damage–induced mutagenesis

Visible-blind bipolar response photodetector based on GaN/ZnO:Ga/GaAs double heterojunctions for dual-band optoelectronic logic operation

Bipolar response photodetectors have sparked considerable interest in optical switches, smart chips, and artificial neuroscience, but invisible ones are still scarce. Here, a visible-blind bipolar response photodetector based on GaN/ZnO:Ga/GaAs double heterojunctions is proposed. Under self-powered conditions, the designed photodetector only shows dual-band photoresponse in the ultraviolet (UV) and infrared (IR) spectrum. Specifically, originating from the absorption characteristics and suitable energy band of multilayered structures, it exhibits positive (negative) photocurrents under UV (IR) illumination. The maximum responsivity of 4.7 mA/W (−1.8 mA/W) under the UV (IR) illumination and fast response time (19.6/36.8 μ s) are achieved. Dual-band optoelectronic logic operations, including OR, AND, NOR, NOT, and NAND, are realized with a single photodetector by precisely regulating the UV and IR illumination. This work paves an approach for the development of visible-blind bipolar photodetection and all-in-one optoelectronic logic gates.

Disruption of deoxyribonucleotide triphosphate biosynthesis leads to RAS proto-oncogene activation and perturbation of mitochondrial metabolism

Band structure modulation of chalcogenide perovskite with Eu as A-site cation

Chalcogenide perovskites with distorted structures, such as BaZrS3 and SrZrS3, are promising photovoltaic materials due to their high stability, strong absorption, and excellent electrical transport properties. Researchers have explored BaZr1-xTixS3 and BaZrS3-xSex alloys to reduce their band gaps, allowing them to absorb lower-energy photons. However, the hexagonal structures of BaTiS3 and BaZrSe3, along with the incompatibility of Ti or Se atoms in BaZrS3, lead to phase separation in these alloys. In this work, using EuZrS3 and Sr0.7Eu0.3ZrS3 alloys as examples, we demonstrate that the band structure of chalcogenide perovskites can be tuned by using Eu as the A-site cation. In EuZrS3, the Eu 4f orbitals contribute to the valence band maximum, thereby raising the valence band and resulting in a narrow bandgap of 0.54 eV. Furthermore, due to the structural and atomic compatibility of Eu with SrZrS3, the Sr1-xEuxZrS3 alloy is designed to fine-tune the band structures of both SrZrS3 and EuZrS3. EuZrS3 also exhibits typical semiconducting characteristics, making it promising for potential optoelectronic devices.

A new regulation mechanism for KCNN4, the Ca2+-dependent K+ channel, by molecular interactions with the Ca2+pump PMCA4b

High-pressure modulation of altermagnetism in MnF2

We investigate the phase transition behavior and electronic band structure of MnF2 under high pressures ranging from 0 to 20 GPa based on first-principles calculations. At ambient pressure, MnF2 in the rutile structure displays antiferromagnetic properties along with significant altermagnetic characteristics. Upon increasing pressure, MnF2 undergoes sequential phase transitions from the rutile structure to the SrI2-type structure and further to the α-PbCl2-type structure. Under high pressure, all three structures of MnF2 exhibit stable altermagnetism, with the maximum spin splitting of 307.5 meV at 3 GPa for the rutile structure, 133.6 meV at 12 GPa for the SrI2-type structure, and 58.4 meV at 20 GPa for the α-PbCl2-type structure. Additionally, our findings suggest that the magnitude of spin splitting can be effectively controlled by modulating the antiferromagnetic exchange interactions and the electron hopping parameters between sublattices. This work elucidates the crystal structure, electronic structure, and altermagnetic properties of MnF2 under high pressure, providing important theoretical foundations for expanding the library of altermagnetic materials.

Hypusinated and unhypusinated isoforms of the translation factor eIF5A exert distinct effects in models of pancreas development and function

Molecule design enabled high efficiency flexible zirconium-based lead-free perovskite scintillator

Metal halide perovskites are the most promising candidates in the field of X-ray detection and imaging. However, the self-absorption and toxicity of lead-based perovskites severely limit their widespread application. Herein, zirconium-based halide perovskites have attracted much attention due to their excellent stability, low toxicity, and suitable bandgap, self-free absorption, wide emission spectrum. In this work, (C8H20N)2ZrCl6 single crystals are synthesized by evaporation crystallization, which presents a large Stokes shift of 203 nm, a high PLQY of 80.77%, and good stability over 180 days. Then, the assembled (C8H20N)2ZrCl6@PDMS films show good flexibility (bending and stretching) and a spatial resolution of 5.8 lp/mm. Thus, this work not only provides a route to explore lead-free metal halide perovskites with broadband emission but also demonstrates flexible zirconium-based scintillators for X-ray scintillation imaging.

The steroid hormone 20-hydroxyecdysone induces lipophagy via the brain-adipose tissue axis by promoting the adipokinetic hormone pathway

Enhancing CZTSSe solar cell efficiency to 11.07% with NaClO-induced Mo texturing for improved light management and carrier collection

This study systematically investigates the optimization mechanism of NaClO solution treatment on Mo substrates for enhancing the optoelectronic performance of CZTSSe thin film solar cells. Experimental results demonstrate that a 10 s NaClO soaking forms a “spike-like” texture on the Mo surface, increasing the average surface roughness difference from 34.52 to 77.75 nm. This significantly enhances light scattering, particularly for photons reaching the back Mo electrode, thereby extending the optical path and promoting photon reabsorption. Additionally, the roughened Mo surface improves the wettability of the precursor solution (contact angle decreases from 19.3° to 12.7°), facilitating the formation of larger CZTSSe grains. Electrical characterization reveals that the NaClO-treated Mo substrate significantly reduces the density of negative charge traps at CZTSSe grain boundaries (contact potential difference increases from −1.1 V to −263 mV), suppressing hole recombination and optimizing carrier collection efficiency. The spike-like structure of the Mo surface also shortens the transport path of hole carriers generated by short-wavelength light, further enhancing collection efficiency. Ultimately, the PCE of CZTSSe devices based on the Mo-10 substrate increases from 9.34% to 11.07%, attributed to the reduction in Rs and J0. This study highlights the critical role of a back electrode interface microstructure design in synergistically optimizing light absorption and carrier transport.