Two–dimensional layered materials (2DLMs) have attracted considerable recent interest as a new material platform for fundamental materials science and potential new technologies. Here we report the ...growth of layered metal halide materials and their optoelectronic properties. BiI3 nanoplates can be readily grown on SiO2/Si substrates with a hexagonal geometry, with a thickness in the range of 10–120 nm and a lateral dimension of 3–10 µm. Transmission electron microscopy and electron diffraction studies demonstrate that the individual nanoplates are high quality single crystals. Micro‐Raman studies show characteristic Ag band at ≈115 cm−1 with slight red‐shift with decreasing thickness, and micro‐photoluminescence studies show uniform emission around 690 nm with blue‐shift with decreasing thickness. Electrical transport studies of individual nanoplates show n‐type semiconductor characteristics with clear photoresponse. Further, the BiI3 can be readily grown on other 2DLMs (e.g., WSe2) to form van der Waals heterostructures. Electrical transport measurements of BiI3/WSe2 vertical heterojunctions demonstrate p–n diode characteristics with gate‐tunable rectification behavior and distinct photovoltaic effect. The synthesis of the BiI3 nanoplates can expand the library of 2DLMs and enable a wider range of van der Waals heterostructures.
The synthesis of the BiI3 nanoplates can greatly expand the library of 2D layered materials to include a broad class of metal halides and enable metal halide‐based van der Waals heterostructures (e.g., BiI3/WSe2, BiI3/WS2) for exciting opportunities in electronics, optoelectronics, and hard radiation detectors.
Gas-nitriding was performed to enhance the surface hardness and fatigue performance of 4140 steel pre-treated with micro-shot peening (MSP). The 4140 steel was solutionized and tempered at ...200 °C/1 h, named as the base metal (BM) with the hardness of 500 HV0.05. Some BM samples were subjected to MSP (i.e., SPBM), and subsequently gas-nitrided at 520 °C/6 h (i.e., NBM). A compound layer of about 10 μm thickness formed on the surface of the NBM sample consisted of nano-grained Fe3N and Fe4N. The NBM sample showed a decline in hardness from the nitrided surface (750 HV0.05) to the matrix (300 HV0.05). In the as-peened condition, the peak residual compressive stress (RCS) was close to −500 MPa, and a very shallow stress field was obtained. After gas-nitriding, the peak RCS decreased to less than −400 MPa, while the affected depth expended to 300 μm. Defects in the compound layer did not deteriorate the fatigue strength/life of the nitrided 4140 steel. The RCS field effectively suppressed fatigue crack initiation and propagation at the surface of the NBM and SPBM samples. By contrast, surface cracks resulted in the fatigue failure of the BM sample.
•Gas-nitriding of 4140 steel pre-treated by micro-shot peening (MSP) was studied.•MSP introduced residual compressive stress (RCS) and refined structure.•Nano-grained Fe3N and Fe4N were formed in the compound layer.•The RCS field became deeper after gas-nitriding.•The sub-surface inclusions caused the fatigue failure of nitrided 4140 steel.
Microbial adhesion reduction as well as platelet compatibility improvement have been suggested as the key requirements for developing blood-contacting synthetic biomaterials. Surface grafting of ...hydrophilic polyethylene glycol chains or alkyl chains with zwitterionic terminal ends has been proposed for reducing microbial or platelet adhesion. Nonetheless, none has been reported to incorporate both polyethylene glycol and zwitterionic terminal functionality on the same surface-grafted alkyl chain. In this investigation, a novel surface modification scheme was reported for grafting zwitterionic alkyl chains with or without polyethylene glycol as the spacer. It was noted the bacterial adhesion reduction capability on the zwitterionic modified surface was dependent upon the use of polyethylene glycol spacer or not and the strain of microbe tested. Besides, the zwitterionic modified ones all showed greater antimicrobial adhesion capability than the surface modified with polyethylene glycol alone. On the other hand, significantly reduced platelet adhesion and activation were found, but with no statistical differences noted among the polyethylene glycol-modified surface and zwitterionic ones, with or without polyethylene glycol spacer. These suggested that the use of polyethylene glycol spacer on the zwitterionic terminated surface could further enhance the antimicrobial adhesion against gram-negative bacterial while still keeping its platelet compatibility.
Fibroblast growth factor-18 (FGF18) has diverse organ development and damage repair roles. However, its role in cardiac homeostasis following hypertrophic stimulation remains unknown. Here we ...investigate the regulation and function of the FGF18 in pressure overload (PO)-induced pathological cardiac hypertrophy. FGF18 heterozygous (Fgf18
) and inducible cardiomyocyte-specific FGF18 knockout (Fgf18-CKO) male mice exposed to transverse aortic constriction (TAC) demonstrate exacerbated pathological cardiac hypertrophy with increased oxidative stress, cardiomyocyte death, fibrosis, and dysfunction. In contrast, cardiac-specific overexpression of FGF18 alleviates hypertrophy, decreased oxidative stress, attenuates cardiomyocyte apoptosis, and ameliorates fibrosis and cardiac function. Tyrosine-protein kinase FYN (FYN), the downstream factor of FGF18, was identified by bioinformatics analysis, LC-MS/MS and experiment validation. Mechanistic studies indicate that FGF18/FGFR3 promote FYN activity and expression and negatively regulate NADPH oxidase 4 (NOX4), thereby inhibiting reactive oxygen species (ROS) generation and alleviating pathological cardiac hypertrophy. This study uncovered the previously unknown cardioprotective effect of FGF18 mediated by the maintenance of redox homeostasis through the FYN/NOX4 signaling axis in male mice, suggesting a promising therapeutic target for the treatment of cardiac hypertrophy.
•DOPO coating is constructed by hydration reaction.•DOPO coating with a super-low p content displays good flame retardancy and anti-dripping ability on PA6 fabric.•DOPO coating effectively inhibits ...heat propagation and improves fire safety.•DOPO coating mainly works in gas-phase.
The application of insoluble 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to develop a durable coating for flame retardant (FR) modification of polyamide 6 (PA6) is of concern and difficult. This study found that the hydration reaction of DOPO provided the possibility of constructing a DOPO coating. Hence, DOPO compound was deposited onto PA6 fabric by dip-coating technique. Then, the impacts of DOPO coating on FR performance, anti-dripping property, smoke and heat release performance of coated PA6 fabric were systematically studied. The limiting oxygen index (LOI) of PA6 fabrics continued to increase with the increase of phosphorus content. However, the coated PA6 fabrics achieved anti-dripping property at a phosphorus content of 0.88 ∼1.75 mg/g. Besides, the heat release ability of coated PA6 reduced sharply at high phosphorus content of 1.75 mg/g, as suggested by a reduction of 20.9% and 21.8% in pHRR and THR, respectively. Moreover, DOPO coating exhibited good washing durability on PA6 fabric because of the hydrogen bond formed between DOPO and PA6, as well as the adhesion of DOPO coating. The coated PA6 fabric could still self-extinguish after 15 washing cycles. Further analysis proved that DOPO played a quenching role in the gas-phase with a weak condensed-phase action. This work points out the right direction for the future research on the preparation of FR PA6 fabric using DOPO derivatives.
Display omitted
The recreational drug γ-hydroxybutyric acid (GHB) is a central nervous system depressant, and can produce euphoria at low doses. GHB is a controlled substance in Taiwan. However, the organic solvents ...γ-butyrolactone (GBL) and 1,4-butanediol (BD), which are unregulated, may be used as an alternative source of GHB. There is no clinical report of analytically confirmed GHB use in Taiwan. We retrospective reviewed the clinical characteristics from the medical charts between May 2017 and April 2020. The urine samples of patients presented to the emergency departments with drug-related complaints were sent for toxicological analysis. Patients with urine samples detected GHB >10 μg/mL by liquid chromatography/tandem mass spectrometry were included. Overall, 11 men and one woman with an average age of 35.3 ± 8.7 years were included. Most patients co-ingested amphetamine (n = 6) and initially presented with depressed consciousness levels (n = 7). One patient presented with out-of-hospital cardiac arrest and one with respiratory depression. All patients regained consciousness within 6 h of admission. All patients used GBL to evade conviction. Although patients recovered with supportive care, respiratory failure and cardiac arrest occurred after GHB/GBL use. It is important to legislate GBL and BD as controlled chemical substances in Taiwan.
A removable acyl group promoted the intramolecular didehydro-Diels–Alder reaction of styrene-ynes under mild reaction conditions is proposed. The reaction is free of metals and catalysts, is easy to ...perform, and exhibits good functional group tolerance, providing a highly chemoselective approach for obtaining the valuable aryldihydronaphthalene derivatives.
Immune-responsive gene 1 (IRG1) encodes aconitate decarboxylase (ACOD1) that catalyzes the production of itaconic acids (ITAs). The anti-inflammatory function of IRG1/ITA has been established in ...multiple pathogen models, but very little is known in cancer. Here, we show that IRG1 is expressed in tumor-associated macrophages (TAMs) in both human and mouse tumors. Mechanistically, tumor cells induce
expression in macrophages by activating NF-κB pathway, and ITA produced by ACOD1 inhibits TET DNA dioxygenases to dampen the expression of inflammatory genes and the infiltration of CD8
T cells into tumor sites. Deletion of
in mice suppresses the growth of multiple tumor types and enhances the efficacy of anti-PD-(L)1 immunotherapy. Our study provides a proof of concept that ACOD1 is a potential target for immune-oncology drugs and
-deficient macrophages represent a potent cell therapy strategy for cancer treatment even in pancreatic tumors that are resistant to T cell-based immunotherapy.
Surface modification layers are performed on the surfaces of biomaterials and have exhibited promise for decoupling original surface properties from bulk materials and enabling customized and ...advanced functional properties. The physical stability and the biological compatibility of these modified layers are equally important to ensure minimized delamination, debris, leaching of molecules, and other problems that are related to the failure of the modification layers and thus can provide a long-term success for the uses of these modified layers. A proven surface modification tool of the functionalized poly-para-xylylene (PPX) system was used as an example, and in addition to the demonstration of their chemical conjugation capabilities and the functional properties that have been well-documented, in the present report, we additionally devised the characterization protocols to examine stability properties, including thermostability and adhesive strength, as well as the biocompatibility, including cell viability and the immunological responses, for the modified PPX layers. The results suggested a durable coating stability for PPXs and firmly attached biomolecules under these stability and compatibility tests. The durable and stable modification layers accompanied by the native properties of the PPXs showed high cell viability against fibroblast cells and macrophages (MΦs), and the resulting immunological activities created by the MΦs exhibited excellent compatibility with non-activated immunological responses and no indication of inflammation.
Topological insulators display unique properties, such as the quantum spin Hall effect, because time-reversal symmetry allows charges and spins to propagate along the edge or surface of the ...topological insulator without scattering. However, the direct manipulation of these edge/surface states is difficult because they are significantly outnumbered by bulk carriers. Here, we report experimental evidence for the modulation of these surface states by using a gate voltage to control quantum oscillations in Bi(2)Te(3) nanoribbons. Surface conduction can be significantly enhanced by the gate voltage, with the mobility and Fermi velocity reaching values as high as ~5,800 cm(2) V(-1) s(-1) and ~3.7 × 10(5) m s(-1), respectively, with up to ~51% of the total conductance being due to the surface states. We also report the first observation of h/2e periodic oscillations, suggesting the presence of time-reversed paths with the same relative zero phase at the interference point. The high surface conduction and ability to manipulate the surface states demonstrated here could lead to new applications in nanoelectronics and spintronics.
PDF
