Current‐density–voltage (J–V) hysteresis in perovskite solar cells (PSCs) is a critical issue because it is related to power conversion efficiency and stability. Although parameters affecting the ...hysteresis have been already reported and reviewed, little investigation is reported on scan‐direction‐dependent J–V curves depending on perovskite composition. This review investigates J–V hysteric behaviors depending on perovskite composition in normal mesoscopic and planar structure. In addition, methodologies toward hysteresis‐free PSCs are proposed. There is a specific trend in hysteresis in terms of J–V curve shape depending on composition. Ion migration combined with nonradiative recombination near interfaces plays a critical role in generating hysteresis. Interfacial engineering is found to be an effective method to reduce the hysteresis; however, bulk defect engineering is the most promising method to remove the hysteresis. Among the studied methods, KI doping is proved to be a universal approach toward hysteresis‐free PSCs regardless of perovskite composition. It is proposed from the current studies that engineering of perovskite film near the electron transporting layer (ETL) and the hole transporting layer (HTL) is of vital importance for achieving hysteresis‐free PSCs and extremely high efficiency.
Photocurrent–voltage hysteresis in perovskite solar cells (PSCs) induced by ion migration combined with nonradiative recombination near the interface depends on perovskite composition and device structure. Among the methods used in the attempt to reduce the hysteresis, potassium‐ion doping is found to be a universal approach toward hysteresis‐free PSCs regardless of perovskite composition.
Poly(vinylidene fluoride) (PVDF) membranes have been extensively applied to scientific research and industrial process due to its outstanding properties such as high thermal stability, good chemical ...resistance and membrane forming properties. This article provides an overview of recent progress on the application and modification of PVDF membranes. The applications include water treatment, membrane distillation, gas separation, pollutants removal, bioethanol recovery, separator for lithium ion battery, support for preparing composite membranes, etc. Subsequently, on the basis of two major problems of PVDF membranes in applications, i.e., membrane fouling and membrane wetting, the hydrophilic modification and hydrophobic modification methods are comprehensively reviewed. Finally, the key issues associated with the modification of PVDF membranes for actual applications are discussed. This paper may provide an insight for the development of PVDF membranes in future.
•A broad overview of applications of PVDF membranes is presented.•Hydrophilic modification to reduce membrane fouling in water treatment.•Hydrophobic modification to improve wetting resistance in membrane contactor.•Improving membrane preparation process and modifying existing membranes.
Abstract
5-Fluorouracil (5-FU) remains the first-line treatment for colorectal cancer (CRC). Although 5-FU initially de-bulks the tumor mass, recurrence after chemotherapy is the barrier to effective ...clinical outcomes for CRC patients. Here, we demonstrate that p53 promotes
WNT3
transcription, leading to activation of the WNT/β-catenin pathway in
Apc
Min/+
/Lgr5
EGFP
mice, CRC patient-derived tumor organoids (PDTOs) and patient-derived tumor cells (PDCs). Through this regulation, 5-FU induces activation and enrichment of cancer stem cells (CSCs) in the residual tumors, contributing to recurrence after treatment. Combinatorial treatment of a WNT inhibitor and 5-FU effectively suppresses the CSCs and reduces tumor regrowth after discontinuation of treatment. These findings indicate p53 as a critical mediator of 5-FU-induced CSC activation via the WNT/β-catenin signaling pathway and highlight the significance of combinatorial treatment of WNT inhibitor and 5-FU as a compelling therapeutic strategy to improve the poor outcomes of current 5-FU-based therapies for CRC patients.
With the current interest in cultured meat, mammalian cell-based meat has mostly been unstructured. There is thus still a high demand for artificial steak-like meat. We demonstrate in vitro ...construction of engineered steak-like tissue assembled of three types of bovine cell fibers (muscle, fat, and vessel). Because actual meat is an aligned assembly of the fibers connected to the tendon for the actions of contraction and relaxation, tendon-gel integrated bioprinting was developed to construct tendon-like gels. In this study, a total of 72 fibers comprising 42 muscles, 28 adipose tissues, and 2 blood capillaries were constructed by tendon-gel integrated bioprinting and manually assembled to fabricate steak-like meat with a diameter of 5 mm and a length of 10 mm inspired by a meat cut. The developed tendon-gel integrated bioprinting here could be a promising technology for the fabrication of the desired types of steak-like cultured meats.
In this study, the possibility of inactivating viral, bacterial, and fungal aerosols in a chamber-type air disinfection system by using a UVC light-emitting-diode (LED) array was investigated and ...inactivation rate constants of each microorganism were calculated in fitting curves of surviving populations. UVC LED array treatment effectively inactivated viral infectivity, achieving 5-log reductions within 45 mJ/cm
for MS2, Qβ, and ϕX174 viruses. UVC LED array effectiveness in inactivating
O157:H7,
serovar Typhimurium,
, and
aerosols achieved 2.5- to 4-log reductions within 1.5 to 4.6 mJ/cm
Also, 4-log reductions of
and
were achieved at a dosage of 23 mJ/cm
using UVC LED array irradiation. The highest UV susceptibility, represented by the inactivation rate constant, was calculated for bacteria, followed by fungi and viruses. UVC LED, an innovative technology, can effectively inactivate microorganisms regardless of taxonomic classification and can sufficiently substitute for conventional mercury UV lamps.
The United Nations Environment Programme (UNEP) convened the Minamata Convention on Mercury in 2013 to ban mercury-containing products in order to ensure human and environmental health. It will be effectuated in 2020 to discontinue use of low-pressure mercury lamps and new UV-emitting sources have to replace this conventional technology. However, the UV germicidal irradiation (UVGI) system still uses conventional UV lamps, and no research has been conducted for air disinfection using UVC LEDs. The research reported here investigated the inactivation effect of aerosolized microorganisms, including viruses, bacteria, and fungi, with an UVC LED module. The results can be utilized as a primary database to replace conventional UV lamps with UVC LEDs, a novel type of UV emitter. Implementation of UVC LED technology is truly expected to significantly reduce the extent of global mercury contamination, and this study provides important baseline data to help ensure a healthier environment and increased health for humanity.
An ultrahigh performance MoS2 photodetector with high photoresponsivity (1.94 × 106 A W–1) and detectivity (1.29 × 1012 Jones) under 520 nm and 4.63 pW laser exposure is demonstrated. This ...photodetector is based on a methyl‐ammonium lead halide perovskite/MoS2 hybrid structure with (3‐aminopropyl)triethoxysilane doping. The performance degradation caused by moisture is also minimized down to 20% by adopting a new encapsulation bilayer of octadecyltrichlorosilane/polymethyl methacrylate.
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•Un-doped CQD (C-CQD), N doped CQD (N-CQD), and NS doped CQD were synthesized with malic acid, alanine, and cysteine.•N and/or S doping lowered the band gap energy, making CQD have ...the visible-light-driven (VLD) antimicrobial activity.•VLD antimicrobial activity increases as the ratio of S decreases during N and S doping.•N-CQD had greater specific surface area, the fluorescence quantum yield and photoluminescence lifetime values than NS-CQD.
The purpose of this study was to investigate the effects of nitrogen and sulfur derived from amino acids on the visible-light-driven (VLD) antimicrobial activity of carbon quantum dots (CQDs) and to establish an optimal doping form. Various CQDs were synthesized by combining malic acid as a carbon source, alanine containing N, and cysteine containing N and S through microwave heating. The results showed that the VLD antimicrobial activity of the CQD against Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative pathogens (Escherichia coli O157:H7 and Salmonella Typhimurium) was improved by N and/or S doping, which increased as the ratio of S decreased. The doping of N and/or S made CQDs have a lower band gap energy, and CQD doped with only N (N-CQDs) exhibited greater specific surface area and fluorescence quantum yields (FLQYs), and longer photoluminescence (PL) lifetimes than CQD doped with N and S (NS-CQDs) even though NS-CQD and N-CQD had similar hand gap energies. Based on these results, the mechanism by which the VLD antimicrobial activity of CQD changes by doping was discussed. Furthermore, this study suggests that for CQD synthesis using food by-products, the more amino acids that can induce the doping of N and/or S, wherein the smaller ratio of S containing amino acids, the better VLD antimicrobial activity the synthesized CQD will have.
Recently, crack segmentation studies have been investigated using deep convolutional neural networks. However, significant deficiencies remain in the preparation of ground truth data, consideration ...of complex scenes, development of an object-specific network for crack segmentation, and use of an evaluation method, among other issues. In this paper, a novel semantic transformer representation network (STRNet) is developed for crack segmentation at the pixel level in complex scenes in a real-time manner. STRNet is composed of a squeeze and excitation attention-based encoder, a multi head attention-based decoder, coarse upsampling, a focal-Tversky loss function, and a learnable swish activation function to design the network concisely by keeping its fast-processing speed. A method for evaluating the level of complexity of image scenes was also proposed. The proposed network is trained with 1203 images with further extensive synthesis-based augmentation, and it is investigated with 545 testing images (1280 × 720, 1024 × 512); it achieves 91.7%, 92.7%, 92.2%, and 92.6% in terms of precision, recall, F1 score, and mIoU (mean intersection over union), respectively. Its performance is compared with those of recently developed advanced networks (Attention U-net, CrackSegNet, Deeplab V3+, FPHBN, and Unet++), with STRNet showing the best performance in the evaluation metrics-it achieves the fastest processing at 49.2 frames per second.
The two oxidation states of ceria nanoparticles, Ce3+ and Ce4+, play a pivotal role in scavenging reactive oxygen species (ROS). In particular, Ce3+ is largely responsible for removing O2− and .OH ...that are associated with inflammatory response and cell death. The synthesis is reported of 2 nm ceria–zirconia nanoparticles (CZ NPs) that possess a higher Ce3+/Ce4+ ratio and faster conversion from Ce4+ to Ce3+ than those exhibited by ceria nanoparticles. The obtained Ce0.7Zr0.3O2 (7CZ) NPs greatly improve ROS scavenging performance, thus regulating inflammatory cells in a very low dose. Moreover, 7CZ NPs are demonstrated to be effective in reducing mortality and systemic inflammation in two representative sepsis models. These findings suggest that 7CZ NPs have the potential as a therapeutic nanomedicine for treating ROS‐related inflammatory diseases.
An optimized ROS scavenging agent: 2 nm‐sized ceria–zirconia nanoparticles (CZ NPs) with increased Ce3+ ratios outperform ceria NPs as scavengers of reactive oxygen species (ROS). The composition‐tuned 7CZ (Ce0.7Zr0.3O2) NPs are superior in reducing inflammation in vitro and decrease the mortality in sepsis in vivo.
A high‐performance ReS2‐based thin‐film transistor and photodetector with high on/off‐current ratio (104), high mobility (7.6 cm2 V−1 s−1), high photoresponsivity (2.5 × 107 A W−1), and fast temporal ...response (rising and decaying time of 670 ms and 5.6 s, respectively) through O2 plasma treatment is reported.
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