Phase-Controlled Multi-Dimensional-Structure SnS/SnS2/CdS Nanocomposite for Development of Solar-Driven Hydrogen Evolution Photocatalyst.

The quest for water-splitting photocatalysts to generate hydrogen as a clean energy source from two-dimensional (2D) materials has enormous implications for sustainable energy solutions. Photocatalytic water splitting, a major field of interest, is focused on the efficient production of hydrogen from renewable resources such as water using 2D materials. Tin sulfide and tin disulfide, collectively known as SnS and SnS2, respectively, are metal sulfide compounds that have gained attention for their photocatalytic properties. Their unique electronic structures and morphological characteristics make them promising candidates for harnessing solar energy for environmental and energy-related purposes. CdS/SnS/SnS2 photocatalysts with two Sn phases (II and IV) were synthesized using a solvothermal method in this study. CdS was successfully placed on a broad SnS/SnS2 plane after a series of characterizations. We found that it is composited in the same way as a core-shell shape. When the SnS/SnS2 phase ratio was dominated by SnS and the structure was composited with CdS, the degradation efficiency was optimal. This material demonstrated high photocatalytic hydrogenation efficiency as well as efficient photocatalytic removal of Cr(VI) over 120 min. Because of the broad light absorption of CdS, the specific surface area, which is the reaction site, became very large. Second, it served as a transport medium for electron transfer from the conduction band (CB) of the SnS to the CB of the SnS2. Because of the composite, these electrons flowed into the CB of CdS, improving the separation efficiency of the photogenerated carriers even further. This material, which was easily composited, also effectively prevented mineral corrosion, which is a major issue with CdS.

Stem Cell Properties of Gastric Cancer Stem-Like Cells under Stress Conditions Are Regulated via the c-Fos/UCH-L3/ß-Catenin Axis.

Gastric cancer stem-like cells (GCSCs) possess stem cell properties, such as self-renewal and tumorigenicity, which are known to induce high chemoresistance and metastasis. These characteristics of GCSCs are further enhanced by autophagy, worsening the prognosis of patients. Currently, the mechanisms involved in the induction of stemness in GCSCs during autophagy remain unclear. In this study, we compared the cellular responses of GCSCs with those of gastric cancer intestinal cells (GCICs) whose stemness is not induced by autophagy. In response to glucose starvation, the levels of ß-catenin and stemness-related genes were upregulated in GCSCs, while the levels of ß-catenin declined in GCICs. The pattern of deubiquitinase ubiquitin C-terminal hydrolase-L3 (UCH-L3) expression in GCSCs and GCICs was similar to that of ß-catenin expression depending on glucose deprivation. We also observed that inhibition of UCH-L3 activity reduced ß-catenin protein levels. The interaction between UCH-L3 and ß-catenin proteins was confirmed, and it reduced the ubiquitination of ß-catenin. Our results suggest that UCH-L3 induces the stabilization of ß-catenin, which is required to promote stemness during autophagy activation. Also, UCH-L3 expression was regulated by c-Fos, and the levels of c-Fos increased in response to autophagy activation. In summary, our findings suggest that the inhibition of UCH-L3 during nutrient deprivation could suppress stress resistance of GCSCs and increase the survival rates of gastric cancer patients.

Identification of TRPC6 as a Novel Diagnostic Biomarker of PM-Induced Chronic Obstructive Pulmonary Disease Using Machine Learning Models.

Chronic obstructive pulmonary disease (COPD) was the third most prevalent cause of mortality worldwide in 2010; it results from a progressive and fatal deterioration of lung function because of cigarette smoking and particulate matter (PM). Therefore, it is important to identify molecular biomarkers that can diagnose the COPD phenotype to plan therapeutic efficacy. To identify potential novel biomarkers of COPD, we first obtained COPD and the normal lung tissue gene expression dataset GSE151052 from the NCBI Gene Expression Omnibus (GEO). A total of 250 differentially expressed genes (DEGs) were investigated and analyzed using GEO2R, gene ontology (GO) functional annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) identification. The GEO2R analysis revealed that TRPC6 was the sixth most highly expressed gene in patients with COPD. The GO analysis indicated that the upregulated DEGs were mainly concentrated in the plasma membrane, transcription, and DNA binding. The KEGG pathway analysis indicated that the upregulated DEGs were mainly involved in pathways related to cancer and axon guidance. TRPC6, one of the most abundant genes among the top 10 differentially expressed total RNAs (fold change ≥ 1.5) between the COPD and normal groups, was selected as a novel COPD biomarker based on the results of the GEO dataset and analysis using machine learning models. The upregulation of TRPC6 was verified in PM-stimulated RAW264.7 cells, which mimicked COPD conditions, compared to untreated RAW264.7 cells by a quantitative reverse transcription polymerase chain reaction. In conclusion, our study suggests that TRPC6 can be regarded as a potential novel biomarker for COPD pathogenesis.

Design of High-Power and High-Density Photovoltaic Modules Based on a Shingled Cell String.

Building-integrated photovoltaic (BIPV) arrays, which are installed on the roofs of buildings as part of urban solar power generation, have created a demand for high-power and high-density photovoltaic (PV) modules to produce high-output power in a limited area. In this paper, a high-power PV module using a shingles technology is designed. When the vertical and horizontal dimensions of the module were 201.78 cm × 96.75 cm in the same area as that of the conventional PV module, the number of cell strips reached 390. When six 65-interconnection shingled strings were connected in series, the output power of 367.8 W was achieved. Compared with a conventional PV module of the same area, the output power was 8% greater.

Optimization of Self-Cleaning Thin-Film Layer for Photovoltaic Applications.

To improve the productivity of a photovoltaic (PV) module, TiO2 thin films of different thicknesses were applied as a self-cleaning layer on soda-lime glass and a Si PV module by spray-coating a TiO2 solution. The structural, optical, and wettability characteristics of the TiO2 thin films were investigated with respect to the thickness. Thermogravimetric-differential thermal analysis, X-ray diffraction, field-emission scanning electron microscopy, contact-angle analysis, ultraviolet-visible spectroscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and a solar simulator were used to analyze the prepared TiO2 thin films. The optimal thickness was determined to be 100 nm. The TiO2 thin film exhibited a self-cleaning ability even after post-annealing at 250 °C. After the self-cleaning ability was confirmed, the TiO2 thin film was applied to the PV module.

Short Ballistic Josephson Coupling in Planar Graphene Junctions with Inhomogeneous Carrier Doping.

We report on short ballistic (SB) Josephson coupling in junctions embedded in a planar heterostructure of graphene. Ballistic Josephson coupling is confirmed by the Fabry-Perot-type interference of the junction critical current I_{c}. The product of I_{c} and the normal-state junction resistance R_{N}, normalized by the zero-temperature gap energy Δ_{0} of the superconducting electrodes, turns out to be exceptionally large close to 2, an indication of strong Josephson coupling in the SB junction limit. However, I_{c} shows a temperature dependence that is inconsistent with the conventional short-junction-like behavior based on the standard Kulik-Omel'yanchuk prediction. We argue that this feature stems from the effects of inhomogeneous carrier doping in graphene near the superconducting contacts, although the junction is in fact in the short-junction limit.

Strong Proximity Josephson Coupling in Vertically Stacked NbSe2-Graphene-NbSe2 van der Waals Junctions.

A layered two-dimensional superconducting material 2H-NbSe2 is used to build a van der Waals heterostructure, where a proximity-coupled superconducting order can be induced in the interfacing materials. Vertically stacked NbSe2-graphene-NbSe2 is fabricated using van der Waals interlayer coupling, producing defect-free contacts with a high interfacial transparency. The atomically thin graphene layer allows the formation of a highly coherent proximity Josephson coupling between the two NbSe2 flakes. The temperature dependence of the junction critical current (Ic) reveals short and ballistic Josephson coupling characteristics that agree with theoretical prediction. The strong Josephson coupling is confirmed by a large junction critical current density of 1.6 × 104 A/cm2, multiple Andreev reflections in the subgap structure of the differential conductance, and a magnetic-field modulation of Ic. This is the first demonstration of strongly proximity-coupled Josephson junctions with extremely clean interfaces in a dry-transfer-stacked van der Waals heterostructure.

Abnormal Threshold Voltage Shifts in P-Channel Low-Temperature Polycrystalline Silicon Thin Film Transistors Under Negative Bias Temperature Stress.

In this research, we have investigated the instability of P-channel low-temperature polycrystalline silicon (poly-Si) thin-film transistors (LTPS TFTs) with double-layer SiO2/SiNx dielectrics. A negative gate bias temperature instability (NBTI) stress was applied and a turn-around behavior phenomenon was observed in the Threshold Voltage Shift (Vth). A positive threshold voltage shift occurs in the first stage, resulting from the negative charge trapping at the SiNx/SiO2 dielectric interface being dominant over the positive charge trapping at dielectric/Poly-Si interface. Following a stress time of 7000 s, the Vth switches to the negative voltage direction, which is "turn-around" behavior. In the second stage, the Vth moves from -1.63 V to -2 V, overwhelming the NBTI effect that results in the trapping of positive charges at the dielectric/Poly-Si interface states and generating grain-boundary trap states and oxide traps.

Synthesis and Characterization of Cadmium Sulfide Nanoparticles by Chemical Precipitation Method.

Cadmium sulfide (CdS) nanoparticles were synthesized by chemical precipitation method using cadmium chloride (CdCl2), sodium sulfide (Na2S) and water as a solvent by varying temperatures from 20-80 degrees C. The nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), High-resolution transmission electron microscopy (HR-TEM) and UV-Visible spectroscopy. XRD pattern revealed cubic crystal structure for all the synthesized CdS nanoparticles. Raman spectra showed first and second order longitudinal optical (LO) phonon vibrational modes of CdS. The size of CdS nanoparticles was found to be in the range of 15-80 nm by FE-SEM analysis, in all cases. The atomic percentage of cadmium and sulfur was confirmed to be 1:1 from EDS analysis. TEM micrograph depicts the spherical shape of the particles and the size is in the range of 15-85 nm while HR-TEM images of CdS nanoparticles exhibit well-resolved lattice fringes of the cubic structure of CdS. The optical properties of CdS were examined by UV-Visible spectroscopy which showed variation in absorption band from 460-480 nm. The band gap was calculated from the absorption edge and found to be in the range of 3.2-3.5 eV which is greater than the bulk CdS.

Local and nonlocal Fraunhofer-like pattern from an edge-stepped topological surface Josephson current distribution.

We report a surface-dominant Josephson effect in superconductor-topological insulator-superconductor (S-TI-S) devices, where a Bi1.5Sb0.5Te1.7Se1.3 (BSTS) crystal flake was adopted as an intervening TI between Al superconducting electrodes. We observed a Fraunhofer-type critical current modulation in a perpendicular magnetic field in an Al-TI-Al junction for both local and nonlocal current biasing. Fraunhofer-type modulation of the differential resistance was also observed in a neighboring Au-TI-Au normal junction when it was nonlocally biased by the Al-TI-Al junction. In all cases, the Fraunhofer-like signal was highly robust to the magnetic field up to the critical field of the Al electrodes, corresponding to the edge-stepped nonuniform supercurrent density arising from the top and rough side surfaces of the BSTS flake, which strongly suggests that the Josephson coupling in a TI is established through the surface conducting channels that are topologically protected.