Explore the vast range of titles available.

The optical properties of transition metal dichalcogenides (TMDs) are known to change dramatically with doping near their excitonic resonances. However, little is known about the effect of doping on the optical properties of TMDs at wavelengths far from these resonances, where the material is transparent and therefore could be leveraged in photonic circuits. We demonstrate the strong electrorefractive response of monolayer tungsten disulfide (WS2) at near-infrared wavelengths (deep in the transparency regime) by integrating it on silicon nitride photonic structures to enhance the light–matter interaction with the monolayer. We show that the doping-induced phase change relative to the change in absorption (|∆n/∆k|) is ~125, which is significantly higher than the |∆n/∆k| observed in materials commonly employed for silicon photonic modulators, including Si and III–V on Si, while accompanied by negligible insertion loss.Strong electrorefractive effects in semiconductor transition metal dichalcogenides (TMDs) at near-infrared wavelengths, where the TMDs are transparent, are observed and used to demonstrate photonic devices based on a composite SiN–TMD platform with large phase modulation, minimal induced loss and low electrical power consumption.

We systematically measure the dielectric function of atomically thin MoS 2 films with different layer numbers and demonstrate that excitonic effects play a dominant role in the dielectric function when the films are less than 5–7 layers thick. The dielectric function shows an anomalous dependence on the layer number. It decreases with the layer number increasing when the films are less than 5–7 layers thick but turns to increase with the layer number for thicker films. We show that this is because the excitonic effect is very strong in the thin MoS 2 films and its contribution to the dielectric function may dominate over the contribution of the band structure. We also extract the value of layer-dependent exciton binding energy and Bohr radius in the films by fitting the experimental results with an intuitive model. The dominance of excitonic effects is in stark contrast with what reported at conventional materials whose dielectric functions are usually dictated by band structures. The knowledge of the dielectric function may enable capabilities to engineer the light-matter interactions of atomically thin MoS 2 films for the development of novel photonic devices, such as metamaterials, waveguides, light absorbers and light emitters.

Epitranscriptomic modifications, particularly N6-methyladenosine (m 6 A), are crucial regulators of gene expression, influencing processes such as RNA stability, splicing, and translation. Traditional computational methods for detecting m 6 A from Nanopore direct RNA sequencing (DRS) data are constrained by their reliance on experimentally validated labels, often resulting in the underestimation of modification sites. Here, we introduce pum6a, an innovative attention-based framework that integrates positive and unlabeled multi-instance learning (MIL) to address the challenges of incomplete labeling and missing read-level annotations. By combining electrical signal features with base alignment data and employing a weighted Noisy-OR probability mechanism, pum6a achieves enhanced sensitivity and accuracy in m 6 A detection, particularly in low-coverage loci. Pum6a outperforms existing methods in identifying m 6 A sites across various cell lines and species, without requiring extensive parameter tuning. We further apply pum6a to study the dynamic regulation of m 6 A demethylases in gastric cancer under hypoxia, revealing distinct roles for FTO and ALKBH5 in modulating m 6 A modifications and uncovering key insights into m 6 A -mediated transcript stability. Our findings highlight the potential of pum6a as a powerful tool for advancing the understanding of epitranscriptomic regulation in health and disease, paving the way for biotechnological and therapeutic applications. RNA modifications like m6A are vital for gene expression but challenging to detect at single-base resolution. Here, the authors introduce pum6a, an advanced computational framework, to enable precise single-base m6A detection and uncovering regulatory mechanisms in hypoxic cancer cells.

Peripheral nerve injury is a serious medical problem with limited surgical and clinical treatment options. It is of great significance to integrate multiple guidance cues in one platform of nerve guidance conduits (NGCs) to promote axonal elongation and functional recovery. Here, a multi‐functional NGC is constructed to promote nerve regeneration by combining ordered topological structure, density gradient of biomacromolecular nanoparticles, and controlled delivery of biological effectors to provide the topographical, haptotactic, and biological cues, respectively. On the surface of aligned polycaprolactone nanofibers, a density gradient of bioactive nanoparticles capable of delivering recombinant human acidic fibroblast growth factor is deposited. On the graded scaffold, the proliferation of Schwann cells is promoted, and the directional extension of neurites from both PC12 cells and dorsal root ganglions is improved in the direction of increasing particle density. After being implanted in vivo for 6 and 12 weeks to repair a 10‐mm rat sciatic nerve defect, the NGC promotes axonal elongation and remyelination, achieving the regeneration of the nerve not only in anatomical structure but also in functional recovery. Taken together, the NGC provides a favorable microenvironment for peripheral nerve regeneration and holds great promise for realizing nerve repair with an efficacy close to autograft. A multi‐functional electrospun fiber‐based NGC is constructed to promote nerve regeneration by combining ordered topological structure, density gradient of biomacromolecular nanoparticles, and controlled delivery of biological effectors to provide the topographical, haptotactic, and biological cues, respectively.

This study aims to evaluate the effect of protocatechuic acid (PCA) on human hair follicle melanocytes (HFM). Normal primary HFM were isolated and cultured till logarithmic period of second passage, then treated with different concentrations of PCA (0.1–200 μmol L ) to study the cell proliferation, melanin contents, tyrosinase activity and protein and mRNA expression of melanogenic genes (tyrosinase-related protein 1 (TRP-1), tyrosinase-related protein 2 (TRP-2), and microphthalmia-associated transcription factor (MITF)) in the cultured HFM. In addition, we have also measured the contents of superoxide dismutase (SOD) and glutathione (GSH) in PCA treated HFM. Vitamin C was used as a positive control. The result showed that PCA can decrease the synthesis of melanin and the tyrosinase activity with = 8.9 μmol L and = 6.4 μmol L , respectively, at the treatment time of 24 hours, without inducing any cytotoxicity in HFM cells. In addition, the mRNA transcription and protein expression levels of TRP-1, TRP-2 and MITF significantly decreased with a dose-dependent manner after 24-hour PCA treated in HFM cells. Furthermore, PCA has significantly increased the SOD and GSH activity in a dose-dependent manner for 24-hour PCA treatment. This study suggested that PCA has an inhibitory effect on the production of melanin through down-regulation of the expression of melanogenesis-related protein and the effect of anti-oxidation, which could be useful for the therapy of melanin overproduction or skin whitening.

Dupilumab was the first biological medication licensed to treat atopic dermatitis (AD), and it has shown remarkable effectiveness and safety in the treatment of moderate-to-severe atopic dermatitis. There are limited drug-related adverse events associated with dupilumab in atopic dermatitis (AD) treatment. Here, we present two cases of local Staphylococcus aureus infection during the treatment of atopic dermatitis with dupilumab.

The mammalian outer hair cells (OHCs) provide a positive mechanical feedback to enhance the cochlea's hearing sensitivity and frequency selectivity. Although the OHC-specific, somatic motor protein prestin is required for cochlear amplification, it remains unclear whether prestin can provide sufficient cycle-by-cycle feedback. In cochlear mechanical modeling, varying amounts of OHC motor activity should provide varying degrees of feedback efficiency to adjust the gain of cochlear amplifier at resonant frequencies. Here we created and characterized two new prestin-hypomorphic mouse models with reduced levels of wild-type prestin. OHCs from these mice exhibited length, total elementary charge movement (Q(max)), charge density, and electromotility intermediate between those of wild-type and prestin-null mice. Remarkably, measurements of auditory brainstem responses and distortion product otoacoustic emissions from these mice displayed wild-type like hearing sensitivities at 4-22 kHz. These results indicate that as low as 26.7% Q(max), 34.0% charge density and 44.0% electromotility in OHCs were sufficient for wild-type-like hearing sensitivity in mice at 4-22 kHz, and that these in vitro parameters of OHCs did not correlate linearly with the feedback efficiency for in vivo gain of the cochlear amplifier. Our results thus provide valuable data for modeling cochlear mechanics and will stimulate further mechanistic analysis of the cochlear amplifier.

Neuromorphic computing based on memristors could help meet the growing demand for data-intensive computing applications such as artificial intelligence. Analogue memristors with multiple conductance states are of particular use in high-efficiency neuromorphic computing, but their weight mapping capabilities are typically limited by small on/off ratios. Here we show that memristors with analogue resistive switching and large on/off ratios can be created using two-dimensional van der Waals metallic materials (graphene or platinum ditelluride) as the cathodes. The memristors use silver as the top anode and indium phosphorus sulfide as the switching medium. Previous approaches have focused on modulating ion motion using changes to the resistive switching layer or anode, which can lower the on/off ratios. In contrast, our approach relies on the van der Waals cathode, which allows silver ion intercalation/de-intercalation, creating a high diffusion barrier to modulate ion motion. The strategy can achieve analogue resistive switching with an on/off ratio up to 10 8 , over 8-bit conductance states and attojoule-level power consumption. We use the analogue properties to perform the chip-level simulation of a convolutional neural network that offers high recognition accuracy. Memristors with on/off ratios up to 10 8 and analogue resistive switching can be created using the intercalation/de-intercalation of silver ions in a two-dimensional metallic electrode to modulate ion migration.

Two-dimensional (2D) materials hold great promise for applications in optoelectronics, quantum information science, and energy conversion due to their remarkable properties imbued by their physical characteristics. Although heterogeneities in their intrinsic structure are the major challenges limiting their synthesis and predictable properties, they also provide a pathway to controllably tune the properties and broaden the potential of 2D materials. Heterogeneities that can be tailored, including defects, dopants, strain, edges, and layer stackings offer transformative opportunities in heterogeneous 2D materials through the introduction of novel properties for technological applications. This article provides a review of recent progress in studying heterogeneities in 2D materials. The review uses examples from our work to develop a strategy to understand the heterogeneities across multiple length scales to link the effect of heterogeneity at the nanoscale with the macroscale properties of 2D materials. We describe specific types of heterogeneities and explore novel synthesis and processing methods for their controlled production with example of the potential impact and applications enabled by their intriguing properties. Finally, we provide a perspective on how to extend the range of tunable properties through further engineering the heterogeneities in 2D materials.