Abstract
Chlorine evolution reaction (CER) is a critical anode reaction in chlor-alkali electrolysis. Although precious metal-based mixed metal oxides (MMOs) have been widely used as CER catalysts, ...they suffer from the concomitant generation of oxygen during the CER. Herein, we demonstrate that atomically dispersed Pt−N
4
sites doped on a carbon nanotube (Pt
1
/CNT) can catalyse the CER with excellent activity and selectivity. The Pt
1
/CNT catalyst shows superior CER activity to a Pt nanoparticle-based catalyst and a commercial Ru/Ir-based MMO catalyst. Notably, Pt
1
/CNT exhibits near 100% CER selectivity even in acidic media, with low Cl
−
concentrations (0.1 M), as well as in neutral media, whereas the MMO catalyst shows substantially lower CER selectivity. In situ electrochemical X-ray absorption spectroscopy reveals the direct adsorption of Cl
−
on Pt−N
4
sites during the CER. Density functional theory calculations suggest the PtN
4
C
12
site as the most plausible active site structure for the CER.
We developed an automatic method for staging periodontitis on dental panoramic radiographs using the deep learning hybrid method. A novel hybrid framework was proposed to automatically detect and ...classify the periodontal bone loss of each individual tooth. The framework is a hybrid of deep learning architecture for detection and conventional CAD processing for classification. Deep learning was used to detect the radiographic bone level (or the CEJ level) as a simple structure for the whole jaw on panoramic radiographs. Next, the percentage rate analysis of the radiographic bone loss combined the tooth long-axis with the periodontal bone and CEJ levels. Using the percentage rate, we could automatically classify the periodontal bone loss. This classification was used for periodontitis staging according to the new criteria proposed at the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. The Pearson correlation coefficient of the automatic method with the diagnoses by radiologists was 0.73 overall for the whole jaw (p < 0.01), and the intraclass correlation value 0.91 overall for the whole jaw (p < 0.01). The novel hybrid framework that combined deep learning architecture and the conventional CAD approach demonstrated high accuracy and excellent reliability in the automatic diagnosis of periodontal bone loss and staging of periodontitis.
Atomically dispersed precious metal catalysts have emerged as a frontier in catalysis. However, a robust, generic synthetic strategy toward atomically dispersed catalysts is still lacking, which has ...limited systematic studies revealing their general catalytic trends distinct from those of conventional nanoparticle (NP)-based catalysts. Herein, we report a general synthetic strategy toward atomically dispersed precious metal catalysts, which consists of “trapping” precious metal precursors on a heteroatom-doped carbonaceous layer coated on a carbon support and “immobilizing” them with a SiO2 layer during thermal activation. Through the “trapping-and-immobilizing” method, five atomically dispersed precious metal catalysts (Os, Ru, Rh, Ir, and Pt) could be obtained and served as model catalysts for unravelling catalytic trends for the oxygen reduction reaction (ORR). Owing to their isolated geometry, the atomically dispersed precious metal catalysts generally showed higher selectivity for H2O2 production than their NP counterparts for the ORR. Among the atomically dispersed catalysts, the H2O2 selectivity was changed by the types of metals, with atomically dispersed Pt catalyst showing the highest selectivity. A combination of experimental results and density functional theory calculations revealed that the selectivity trend of atomically dispersed catalysts could be correlated to the binding energy difference between *OOH and *O species. In terms of 2 e– ORR activity, the atomically dispersed Rh catalyst showed the best activity. Our general approach to atomically dispersed precious metal catalysts may help in understanding their unique catalytic behaviors for the ORR.
Recent advance in sequencing technology has enabled comprehensive profiling of genetic alterations in cancer. We have established a targeted sequencing platform using next-generation sequencing (NGS) ...technology for clinical use, which can provide mutation and copy number variation data. NGS was performed with paired-end library enriched with exons of 183 cancer-related genes. Normal and tumor tissue pairs of 60 colorectal adenocarcinomas were used to test feasibility. Somatic mutation and copy number alteration were analyzed. A total of 526 somatic non-synonymous sequence variations were found in 113 genes. Among these, 278 single nucleotide variations were 232 different somatic point mutations. 216 SNV were 79 known single nucleotide polymorphisms in the dbSNP. 32 indels were 28 different indel mutations. Median number of mutated gene per tumor was 4 (range 0-23). Copy number gain (>X2 fold) was found in 65 genes in 40 patients, whereas copy number loss (<X0.5 fold) was found in 103 genes in 39 patients. The most frequently altered genes (mutation and/or copy number alteration) were APC in 35 patients (58%), TP53 in 34 (57%), and KRAS in 24 (40%). Altered gene list revealed ErbB signaling pathway as the most commonly involved pathway (25 patients, 42%). Targeted sequencing platform using NGS technology is feasible for clinical use and provides comprehensive genetic alteration data.
•Degradation efficiency of PFOS by electron beam was evaluated.•Twelve decomposition products were confirmed by LC-MS/MS, HPLC, and IC data matching.•Seven short-chain PFCA radiolytic products were ...formed due to repeated CF2 cleavage.•Decreased toxicity of by-products with reducing C-chain and head group by e-beam.•E-beam radiation process is ecotoxicologically effective for the treatment of PFOS.
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Perfluorooctane sulfonate (PFOS) has been found in wastewater treatment plants (WWTPs) and in surface water as a result of domestic uses of textiles, electronics, and surfactants. The detection of PFOS in the aqueous environment has been linked to hazardous biological effects including estrogenicity and genotoxicity. To provide an alternative to conventional processes, one of the radical-based advanced oxidation and reduction processes being tested for treatment of refractory compounds in water, involves the use of an electron beam. Therefore, the aims of this study were to investigate the degradation efficiency of PFOS (100mg/L) by electron beam, to evaluate the predicted toxicity of the radiolysis products using the ECOSAR model, and to identify the radiolytic products of PFOS. As a result of using the ECOSAR model, the toxicity levels of by-products after electron beam treatment were reduced by decreasing the carbon-chain number of PFOS. The molecular structures of the radiolytic products were elucidated using authentic standards via liquid chromatography and tandem mass spectrometry, and by the interpretation of MS2 fragmentation patterns of each product using liquid chromatography with quadrupole time of-flight mass spectrometry (LC-QTOF-MS). In total, ten radiolytic products were confirmed by LC-MS/MS, HPLC, and IC data matching with commercial standards. The two radiolytic substances produced during irradiation with an electron beam were predicted by LC-QTOF-MS. This study led to an understanding of the role of electron beams in the transformation of parent compounds and to the decomposition products created when an electron beam is applied to treat perfluorinated compounds.
We investigated the optical and electrical properties of red AlGaInP light-emitting diodes (LEDs) as functions of chip size, p-cladding layer thickness, and the number of multi-quantum wells (MQWs). ...External quantum efficiency (EQE) decreased with decreasing chip size. The ideality factor gradually increased from 1.47 to 1.95 as the chip size decreased from 350 μm to 15 μm. This indicates that the smaller LEDs experienced larger carrier loss due to Shockley-Read-Hall nonradiative recombination at sidewall defects. S parameter, defined as ∂lnL/∂lnI, increased with decreasing chip size. Simulations and experimental results showed that smaller LEDs with 5 pairs of MQWs had over 30% higher IQE at 5 A/cm
than the LED with 20 pairs of MQWs. These results show that the optimization of the number of QWs is needed to obtain maximum EQE of micro-LEDs.
Alkaline water electrolysis (AWE) systems offer a cost‐effective and scalable approach for large‐scale hydrogen production using renewable energy sources. However, their susceptibility to load ...fluctuations, particularly the reverse‐current (RC) phenomenon during shutdown events, poses a significant challenge to the long‐term stability and scalability of these systems. Herein, a catalytic approach for enhancing the RC tolerance in AWE systems by using Pb‐decorated Ni cathode catalysts (Pb/Ni) is introduced. The oxidation of Pb/Ni by repeated RC lowers the electromotive force for the reverse current operation, and consequently, imparts RC tolerance. Intriguingly, contrary to the expectation that the decoration with lead, an inert material for the hydrogen evolution reaction (HER), will interfere with the hydrogen generation of the Ni catalyst, the presence of Pb on the Ni cathode after the RC flow promotes both the proton desorption and water‐dissociation steps, improving the HER activity. Furthermore, the AWE stack testing with Pb/Ni catalysts is perfectly operated, demonstrating remarkably enhanced RC tolerance during startup/shut‐down (SU/SD) testing protocol. This paper presents a new strategy for mitigating the AWE performance degradation induced by RC flow and for achieving Pb/Ni catalysts with improved operational durability against RC flow in AWE systems.
The transient stability of the catalyst caused by the reverse‐current phenomenon during the shutdown of the AWE system by load fluctuations is one of the most challenging limitations to address. This study introduces a catalytic approach for enhancing the RC by decorating lead on Ni catalysts. The surface decoration of the Ni catalyst with Pb (Pb/Ni) catalyst exhibits improved HER activity as well as remarkable RC‐flow resistance.
Targeted protein degradation allows targeting undruggable proteins for therapeutic applications as well as eliminating proteins of interest for research purposes. While several degraders that harness ...the proteasome or the lysosome have been developed, a technology that simultaneously degrades targets and accelerates cellular autophagic flux is still missing. In this study, we develop a general chemical tool and platform technology termed AUTOphagy-TArgeting Chimera (AUTOTAC), which employs bifunctional molecules composed of target-binding ligands linked to autophagy-targeting ligands. AUTOTACs bind the ZZ domain of the otherwise dormant autophagy receptor p62/Sequestosome-1/SQSTM1, which is activated into oligomeric bodies in complex with targets for their sequestration and degradation. We use AUTOTACs to degrade various oncoproteins and degradation-resistant aggregates in neurodegeneration at nanomolar DC
values in vitro and in vivo. AUTOTAC provides a platform for selective proteolysis in basic research and drug development.
Developing efficient and inexpensive electrocatalysts for the hydrogen evolution reaction (HER) in alkaline water electrolysis plays a key role for renewable hydrogen energy technology. The slow ...reaction kinetics of HER in alkaline solutions, however, has hampered advances in high-performance hydrogen production. Herein, we investigated the trends in HER activity with respect to the binding energies of Ni-based thin film catalysts by incorporating a series of oxophilic transition metal atoms. It was found that the doping of oxophilic atoms enables the modulation of binding abilities of hydrogen and hydroxyl ions on the Ni surfaces, leading to the first establishment of a volcano relation between OH-binding energies and alkaline HER activities. In particular, Cr-incorporated Ni catalyst shows optimized OH-binding as well as H-binding energies for facilitating water dissociation and improving HER activity in alkaline media. Further enhancement of catalytic performance was achieved by introducing an array of three-dimensional (3D) Ni nanohelixes (NHs) that provide abundant surface active sites and effective channels for charge transfer and mass transport. The Cr dopants incorporated into the Ni NHs accelerate the dissociative adsorption process of water, resulting in remarkably enhanced catalytic activities in alkaline medium. Our approach can provide a rational design strategy and experimental methodology toward efficient bimetallic electrocatalysts for alkaline HER using earth-abundant elements.
The heterogeneous catalysis is widely recognized to promote polysulfide fragmentations can play a key role for the rate capability enhancement of lithium sulfur batteries (LSB). In this study, we ...report the most active catalysts (Ta2O5) for LSB which showed an enhanced rate capability (914 mAh g−1 at 5 C) in comparison with the previously reported catalysts, TiN (865 mAh g−1 at 5 C). The addition of Ta2O5 into the carbon-coated separator facilitates the chemical disproportionation of reaction intermeditates, Li2S4 into Li2S8 and Li2S effectively, which leads to the greatly lengthened second plateau in discharge profile. The heterogeneous catalysis of Ta2O5 is clearly verified with the UV–Vis spectra directly showing the change of Li2S4 concentration and the battery performance tests without any active elemental sulfur.
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•Heterogeneous catalysts as reaction intermediates can enhance battery performance.•Ta2O5 is one of the most promising heterogeneous catalysts for Li-S battery.•Strong chemical bonding between S and Ta2O5 result in catalytic effect of Ta2O5.•Ta2O5 can accelerate slow disproportionation reaction of LiPS.•Modified separator can help achieving long cycle life and enhanced rate capability.
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