Gene selection is an important issue in microarray data processing. In this paper, we propose an efficient method for selecting relevant genes. First, we use spectral biclustering to obtain the best two eigenvectors for class partition. Then gene combinations are selected based on the similarity between the genes and the best eigenvectors. We demonstrate our semi-unsupervised gene selection method using two microarray cancer data sets, i.e., the lymphoma and the liver cancer data sets, where our method is able to identify a single gene or a two-gene combinations which can lead to predictions with very high accuracy.
Directly probing deep tissue activities from body surfaces offers a noninvasive approach to monitoring essential physiological processes1-3. However, this method is technically challenged by rapid signal attenuation toward the body surface and confounding motion artifacts4-6 primarily due to excessive contact impedance and mechanical mismatch with conventional electrodes. Herein, by formulating and directly spray coating biocompatible two-dimensional nanosheet ink onto the human body under ambient conditions, we create microscopically conformal and adaptive van der Waals thin films (VDWTFs) that seamlessly merge with non-Euclidean, hairy, and dynamically evolving body surfaces. Unlike traditional deposition methods, which often struggle with conformality and adaptability while retaining high electronic performance, this gentle process enables the formation of high-performance VDWTFs directly on the body surface under bio-friendly conditions, making it ideal for biological applications. This results in low-impedance electrically functionalized body surfaces (EFBS), enabling highly robust monitoring of biopotential and bioimpedance modulations associated with deep-tissue activities, such as blood circulation, muscle movements, and brain activities. Compared to commercial solutions, our VDWTF-EFBS exhibits nearly two-orders of magnitude lower contact impedance and substantially reduces the extrinsic motion artifacts, enabling reliable extraction of bioelectrical signals from irregular surfaces, such as unshaved human scalps. This advancement defines a technology for continuous, noninvasive monitoring of deep-tissue activities during routine body movements.
Dataset of the article "Unriddling the role of alkali metal cations and Pt-surface hydroxide in alkaline hydrogen evolution reaction" accepted in Nature Catalysis. The optimized geometries (in VASP format) and full 100-ps AIMD trajectories (in xyz format) of Pt(111)/water interface with alkali metal cations (Li+, Na+, K+) and with or without surface *OH.
Recently, the rapid development of the anion exchange membrane (AEM) shows a promising future in the commercialization of low cost and long-term stable AEM based fuel cells and water electrolyzers. AEM features an alkaline electrolyte, where non-precious metal ORR catalysts possess high ORR activity and can replace Pt catalysts. However, Pt is still the best selection for HOR catalysts in the alkaline medium. The HOR activity of Pt is highly pH-dependent and decreases over two orders of magnitude when pH increases from 1 to 14. Thus, the sluggish anodic HOR reaction becomes the most critical issue in the development of AEMFCs. The major reason for the slow HER/HOR process in the alkaline electrolyte is ascribed to the positive shift of potential of zero free charge (PZFC) while pH value goes up from pH = 1 to 14. As PZFC shifts to a more positive value, it becomes more difficult for OH ads to get adsorbed on the Pt surface to facilitate the water dissociation or the removal of H ads . Tailoring Pt surface with a second transition metal hydroxides has been proved to be an effective method to enhance the HOR activity on Pt, but at the sacrifice of tremendous active surface Pt sites (~50%), leading to the waste of electrochemical surface area (ECSA) and the decrease of the maximum mass activity (MA). Herein, taking advantage of the single-atom tailoring strategy, we have achieved single Rh atom tailoring of Pt nanowires for the optimization of surface oxophilicity for OH adsorption to boost the HER/HOR activity in the alkaline condition. The HOR activity of PtRh nanowires is highly sensitive to the oxophilicity of Pt surface and the structure of surface Rh species. Pt surface with higher oxophilicity usually shows a higher HER/HOR rate in alkaline conditions because the sluggish Volmer step can be accelerated by the early adsorption of OH in the H upd potential region. However, both the HOR and HER activity of the PtRh nanowires reach the maximum value only when the Rh is in the single-atom form and the Pt surface is under the optimum oxophilicity. It was revealed by the XANES spectra that the single Rh atoms under 0 V vs. RHE are positively charged. The in-situ and ex-situ XANES spectra of Rh L edge show that Rh atoms are redox-active and electroactive. The positive shift of the edge position from Rh foil to Rh single atoms under 0 V vs. RHE indicates that the single Rh atoms are slightly oxidized and coordinated with eight Pt and one O, even under 0 V vs. RHE. When the applied potential increases, Rh-O bond intensity increases, and Rh-Pt bond intensity decreases, as expected from the oxidation from slightly charged single atom Rh to single Rh(OH) x species. We also noted that the Rh-O peak shift positively when potentials shifts from 0.54 V to 0 V vs. RHE, indicating an elongated Rh-O bond at a lower overpotential, which indicates that the adsorbed oxygen species under 0 V are not the OH from Rh(OH) x and should be weakly adsorbed OH or H 2 O ↓ . The fitting of in-situ EXAFS of Rh L edge on the SARh-PtNWs also confirms that the Rh atoms are bonded with eight Pt atoms and one O , and no Rh-Rh interaction is found throughout the whole HOR range. The existence of single atom Rh-OH ads or Rh-H 2 O ↓ under 0 V vs. RHE significantly facilitates the sluggish Volmer step at the minimal sacrifice of the active Pt sites where H 2 dissociation and H adsorption takes place. When the surface Rh concentration surpasses a critical point, singly dispersed Rh atoms start to aggregate to a continuously distributed Rh layer which significantly increases the surface oxophilicity for earlier OH adsorption, but at the sacrificial of highly active Pt site for H 2 dissociation and high H ads surface coverage. HOR/HER requires an equilibrium of H adsorption and OH/H 2 O adsorption on the Pt surface to reach the maximum oxidation/production rate of H 2 . However, both the Tafel step and the Volmer step on the Rh rich Pt surface are far away from the optimum condition, Also, the excess Rh and adsorbed water may form a rigid water layer that covers the Pt surface and prevent it from accessing the H 2 , results in the decreased overall HOR activity. In short, we have synthesized single atom Rh tailored Pt nanowires and used in-situ EXAFS and XANES to prove the existence of the surface Rh-OH ads or Rh-H 2 O ↓ which significantly facilitate the HER and HOR process. Figure 1
Abstract Bionic impeller blades can improve cavitation performance of waterjets. A Special kind of bionic impeller with non-smooth leading edge is designed to improve the NPSH (net positive suction head) performance of waterjets. Based on the cavitation experiment of the waterjet with original impeller, a reliable CFD method using the commercial software StarCCM+ is verified. The detailed flow field of the bionic blades is obtained by simulating the viscous flow field. The stream line, pressure distribution and vortex reveal the mechanism of bionic blades flow adjustment. The influence of bionic impeller factors, which are the amplitude, the interval and the phase, on cavitation performance is systematically studied. The area and volume of the blade cavitation pattern is used to characterize the blade cavitation performance. An efficient method of cavitation pattern recognition is proposed to determine the information of the blade cavitation pattern accurately. A feasible cavitation-adjustment method is proposed to improve the hydraulic performance by optimizing the cavitation distribution and strength.
Au-doped PtAgRhCu alloy wavy nanowire electrocatalysts deliver ultrahigh mass activity and selectivity for alcohol oxidation, enabling energy-saving hydrogen production and selective alcohol upgrading via alcohol-assisted water electrolysis.
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