Previous studies have implicated targeting Pim-1 proto-oncogene, serine/threonine kinase (PIM1) as a preventive measure against high glucose-induced cellular stress and apoptosis. This study aimed to reveal the potential role and regulatory mechanism of PIM1 in diabetic retinopathy. Human retinal microvascular endothelial cells (hRMECs) underwent high glucose induction, and fluctuations in PIM1 levels were assessed.
View Article and Find Full Text PDFInherent symmetry breaking at the interface has been fundamental to a myriad of physical effects and functionalities, such as efficient spin-charge interconversion, exotic magnetic structures and an emergent bulk photovoltaic effect. It has recently been demonstrated that interface asymmetry can induce sizable piezoelectric effects in heterostructures, even those consisting of centrosymmetric semiconductors, which provides flexibility to develop and optimize electromechanical coupling phenomena. Here, by targeted engineering of the interface symmetry, we achieve piezoelectric phenomena behaving as the electrical analogue of the negative Poisson's ratio.
View Article and Find Full Text PDFGiven its innate coupling with wavefunction geometry in solids and its potential to boost the solar energy conversion efficiency, the bulk photovoltaic effect (BPVE) has been of considerable interest in the past decade. Initially discovered and developed in ferroelectric oxide materials, the BPVE has now been explored in a wide range of emerging materials, such as Weyl semimetals, van der Waals nanomaterials, oxide superlattices, halide perovskites, organics, bulk Rashba semiconductors and others. However, a feasible experimental approach to optimize the photovoltaic performance is lacking.
View Article and Find Full Text PDFSemiconductor technology, which is rapidly evolving, is poised to enter a new era for which revolutionary innovations are needed to address fundamental limitations on material and working principle level. 2D semiconductors inherently holding novel properties at the atomic limit show great promise to tackle challenges imposed by traditional bulk semiconductor materials. Synergistic combination of 2D semiconductors with functional ferroelectrics further offers new working principles, and is expected to deliver massively enhanced device performance for existing complementary metal-oxide-semiconductor (CMOS) technologies and add unprecedented applications for next-generation electronics.
View Article and Find Full Text PDFFlexible and self-powered deep ultraviolet (UV) photodetectors are pivotal for next-generation electronic skins to enrich human life quality. The fabrication of epitaxial β-GaO thin films is challenging on flexible substrates due to high-temperature growth requirements. Herein, β-GaO ([Formula: see text] 0 1) films are hetero-epitaxially grown on ultra-thin and environment-friendly muscovite mica which is the first time β-GaO epitaxy growth on any flexible substrate.
View Article and Find Full Text PDFInterfaces in heterostructures have been a key point of interest in condensed-matter physics for decades owing to a plethora of distinctive phenomena-such as rectification, the photovoltaic effect, the quantum Hall effect and high-temperature superconductivity-and their critical roles in present-day technical devices. However, the symmetry modulation at interfaces and the resultant effects have been largely overlooked. Here we show that a built-in electric field that originates from band bending at heterostructure interfaces induces polar symmetry therein that results in emergent functionalities, including piezoelectricity and pyroelectricity, even though the component materials are centrosymmetric.
View Article and Find Full Text PDFNeuromorphic visual sensory and memory systems, which can perceive, process, and memorize optical information, represent core technology for artificial intelligence and robotics with autonomous navigation. An optoelectronic synapse with an elegant integration of biometric optical sensing and synaptic learning functions can be a fundamental element for the hardware-implementation of such systems. Here, we report a class of ferroelectric field-effect memristive transistors made of a two-dimensional WS semiconductor atop a ferroelectric PbZrTiO (PZT) thin film for optoelectronic synaptic devices.
View Article and Find Full Text PDFIt has been recently shown that the strain gradient is able to separate the light-excited electron-hole pairs in semiconductors, but how it affects the photoelectric properties of the photo-active materials remains an open question. Here, we demonstrate the critical role of the strain gradient in mediating local photoelectric properties in the strained BiFeO thin films by systematically characterizing the local conduction with nanometre lateral resolution in both dark and illuminated conditions. Due to the giant strain gradient manifested at the morphotropic phase boundaries, the associated flexo-photovoltaic effect induces on one side an enhanced photoconduction in the R-phase, and on the other side a negative photoconductivity in the morphotropic [Formula: see text]-phase.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2019
The light control of nonvolatile nanoscale memories could represent a fundamental step toward novel optoelectronic devices with memory and logic functionalities. However, most of the proposed devices exhibit insufficient control in terms of the reversibility, data retention, photosensitivity, limited-photoactive area, and so forth. Here, in a proof-of-concept work, we demonstrate the use of the tip-enhanced bulk photovoltaic (BPV) effect to realize programmable nanoscopic writing of nonphotoactive electronic devices by light control.
View Article and Find Full Text PDFMultiferroic BiFeO crystals were investigated by means of micro-Raman spectroscopy using the laser wavelengths of 442 nm (resonant conditions) and 633 nm (non-resonant conditions). The azimuthal angle dependence of the intensity of the Raman modes allowed their symmetry assignment. The experimental data are consistent with a simulation based on Raman tensor formalism.
View Article and Find Full Text PDFDefect-engineered perovskite oxides that exhibit ferroelectric and photovoltaic properties are promising multifunctional materials. Though introducing gap states by transition metal doping on the perovskite B-site can obtain low bandgap (i.e.
View Article and Find Full Text PDFIt is highly desirable to discover photovoltaic mechanisms that enable enhanced efficiency of solar cells. Here we report that the bulk photovoltaic effect, which is free from the thermodynamic Shockley-Queisser limit but usually manifested only in noncentrosymmetric (piezoelectric or ferroelectric) materials, can be realized in any semiconductor, including silicon, by mediation of flexoelectric effect. We used either an atomic force microscope or a micrometer-scale indentation system to introduce strain gradients, thus creating very large photovoltaic currents from centrosymmetric single crystals of strontium titanate, titanium dioxide, and silicon.
View Article and Find Full Text PDFManipulation of ferroic order parameters, namely (anti-)ferromagnetic, ferroelectric, and ferroelastic, by light at room temperature is a fascinating topic in modern solid-state physics due to potential cross-fertilization in research fields that are largely decoupled. Here, full optical control, that is, reversible switching, of the ferroelectric/ferroelastic domains in BiFeO thin films at room temperature by the mediation of the tip-enhanced photovoltaic effect is demonstrated. The enhanced short-circuit photocurrent density at the tip contact area generates a local electric field well exceeding the coercive field, enabling ferroelectric polarization switching.
View Article and Find Full Text PDFDomain walls, which are intrinsically two dimensional nano-objects exhibiting nontrivial electronic and magnetic behaviours, have been proven to play a crucial role in photovoltaic properties of ferroelectrics. Despite this recognition, the electronic properties of domain walls under illumination until now have been accessible only to macroscopic studies and their effects upon the conduction of photovoltaic current still remain elusive. The lack of understanding hinders the developing of nanoscale devices based on ferroelectric domain walls.
View Article and Find Full Text PDFA new method for the determination of nine organophosphorus pesticides (OPPs): Dichlorvos, methamidophos, acephate, diazinon, dimethoate, chlorpyrifos, parathion-methyl, malathion and parathion-ethyl in concentrated fruit juice was developed using the cloud point extraction coupled with ultrasonic-assisted back-extraction prior to gas chromatography with flame photometric detection (GC-FPD) analysis. The parameters and variables that affect the extraction were investigated. Under optimum conditions: a solution containing 6% (W/V) polyethylene glycol 6000 (PEG 6000) and 20% (W/V) Na(2)SO(4) for the extraction of the OPPs.
View Article and Find Full Text PDFA simple and sensitive cloud point extraction high-performance liquid chromatography method is proposed for the determination of isoniazid in blood. The procedure is based on the product of the reaction of isoniazid with benzaldehyde. It can be validated that there is a linear relationship between the signal of isonicotinyl hydrazone and the concentration of isoniazid.
View Article and Find Full Text PDFA highly sensitive method for the determination of arprocarb (AC), carbofuran (CF), isoprocarb (IC), and fenobucarb (FC) is proposed. The method is based on alkaline hydrolysis of the four carbamate pesticides, and the resultant hydrolysis products are reacted with 4-aminoantipyrene (AP) to give four red color products. The colored compounds are enriched and separated by cloud point extraction (CPE) method, and the coacervate phase containing the compounds is determined with a high-performance liquid chromatography (HPLC) system in the visible region.
View Article and Find Full Text PDFIsoniazid (INH) reacted with p-dimethylaminobenzaldehyde (DABD) in the presence of trichloroacetic acid to give isonicotinylhydrazone (INZ) having lambda(max) 365nm. Cloud point extraction (CPE) is carried out to extract INH and IHZ in aqueous solutions using surfactant poly(ethylene glycol) 4000 (PEG4000), respectively. Langmuir model is used to study the adsorption behaviors of the two solutes on micelles of PEG4000.
View Article and Find Full Text PDF4-Amino-4'-nitrobiphenyl, which is formed by catalytic effect of trichlorfon on sodium perborate oxidizing benzidine, is extracted with a cloud point extraction method and then detected using a high performance liquid chromatography with ultraviolet detection (HPLC-UV). Under the optimum experimental conditions, there was a linear relationship between trichlorfon in the concentration range of 0.01-0.
View Article and Find Full Text PDFA CPE-HPLC (UV) method was developed for the determination of Sudan (I-IV) dyes, non-ionic surfactant Triton X-100 was used to extract and preconcentrate Sudan dyes from chilli powder prior to their determination by HPLC-UV. The separation and determination of Sudan dyes was then carried out in the HPLC-UV system with isocratic elution, and the detector was set at 500 nm. The parameters and variables that affect the extraction were investigated.
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