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Micro-arc oxidation (MAO) is one of the most effective techniques for producing ceramic coatings on metal surfaces and is widely used for metal surface modification. However, energy is wasted due to the dispersion of energy when handling large workpieces. Scanning micro-arc oxidation (SMAO) is a coating process developed based on conventional micro-arc oxidation, where electrode confinement is carried out during the scanning process thus saving energy. In this paper, SMAO is further investigated and simulated using simulation software, which greatly saves the experimental cost. The results show that increasing the number of scans increases the thickness of the micro-arc oxidized film, while the scanning speed is the opposite. Both anodic oxidation and passivation zones exist at the periphery of the SMAO region, the roughness of the SMAO film layer decreases from the center to the edge, and the anodic oxidation reaction mainly occurs at the edge zone of the discharge region. The thickness of the film layer is about 17 um in a single scan, and the thickness of the film layer can reach 50 um after several scans, and there is a porous structure on its surface, which is favorable for the adsorption and diffusion of gas molecules. The results show that SMAO is suitable for producing large-volume and large-area metal surface coating, and it is a feasible metal surface coating process. [ABSTRACT FROM AUTHOR]

There is an urgent need for miniature heat sinks with superhydrophobic and efficient heat transfer properties for power-intensive electronic devices to operate properly under harsh conditions. Therefore, this paper firstly establishes the simulation model of surface wetting performance of miniature heat sink with square columnar array microstructure based on the phase field method and investigates the effect of dimensional parameters on the surface wetting performance of miniature heat sink. Then, miniature heat sinks with square columnar array microstructures of different dimensional parameters were prepared by wire electrical discharge machining (WEDM), and the 2D micromorphology, surface wetting performance, and heat transfer performance of the miniature heat sinks were characterized. The experimental results show that the simulation model has a high accuracy and the difference between the experimental results is less than 4.1%. The contact angle of the miniature heat sink with column width, column distance, and column height of 400 μm, 400 μm, and 1000 μm, respectively, is 151.4°. The heat source temperature with this miniature heat sink installed is 109.5 °C, which is 32.1 °C lower than the heat source temperature of 141.6 °C with the polished purple copper block installed without microstructure, a reduction of up to 22.7%. The miniature heat sink is prepared by WEDM in one-step, without any chemical modification treatment, to obtain super hydrophobic and efficient heat transfer performance. [ABSTRACT FROM AUTHOR]

To address the problems of high process complexity, uncontrollable and unpredictable wetting performance, and expensive processing equipment for the superhydrophobic surfaces of metal substrates prepared by conventional methods, in this paper, superhydrophobic surfaces consisting of rectangular cross-section double-scale arrays of microstructure were prepared on HT250 substrates using wire electrical discharge machining (WEDM). First, a simulation model of the surface wetting performance of the rectangular cross-section double-scale array microstructure prepared by WEDM is established, to analyze the effect of peak current and pulse width on the surface roughness, dimensional parameters, and surface wetting performance of the discharge micro-crater structure; the effect of the width and distance of the rectangular cross-section on the surface wetting performance of the double-scale array of microstructure with rectangular cross-section is further discussed. And the simulation model is experimentally verified. The results of the study in this paper indicate that at a peak current of 12A, a pulse width of 20 μs, and a rectangular cross-section with a width and distance of 200 μm, the contact angles of the rectangular cross-section double-scale array microstructure surface obtained from simulation and experiment are 133° and 135.3°, respectively, the prediction accuracy of the simulation model is 98.3%, and the surface has superhydrophobic performance after low surface energy treatment, with a static contact angle of 151.5°. This study not only extends the application area of WEDM, but also provides a theoretical reference for the design of metal substrate microstructure surface, realizes the controllable preparation and accurate prediction of wetting performance of metal substrate microstructure surface, and has important guiding significance for the preparation of metal substrate superhydrophobic surfaces. [ABSTRACT FROM AUTHOR]

Reduced Na-K-ATPase activity has close relationship with cardiomyocyte death. Reactive oxygen species (ROS) also plays an important role in cardiac cell damage. It has been proved that Na-K-ATPase and ROS form a feed-forward amplifier. The aim of this study was to explore whether DRm217, a proved Na/K-ATPase's DR-region specific monoclonal antibody and direct activator, could disrupt Na-K-ATPase/ROS amplifier and protect cardiac cells from ROS-induced injury. We found that DRm217 protected myocardial cells against hydrogen peroxide (HO)-induced cardiac cell injury and mitochondrial dysfunction. DRm217 also alleviated the effect of HO on inhibition of Na-K-ATPase activity, Na-K-ATPase cell surface expression, and Src phosphorylation. HO-treatment increased intracellular ROS, mitochondrial ROS and induced intracellular Ca, mitochondrial Ca overload. DRm217 closed Na-K-ATPase/ROS amplifier, alleviated Ca accumulation and finally inhibited ROS and mitochondrial ROS generation. These novel results may help us to understand the important role of the Na-K-ATPase in oxidative stress and oxidative stress-related disease. [ABSTRACT FROM AUTHOR]

To identify sociodemographic characteristics and risk factor of Demodex infestation, 756 students aged 13-22 years in Xi'an, China were sampled for the school-based cross-sectional study. Demodex was examined using the cellophane tape method (CTP). The results showed that the total detection rate of Demodex was 67.6%. Logistic regression analysis revealed that five variables (gender, residence, sharing sanitary ware, frequency of face-wash per day, and use of facial cleanser) were found to be uncorrelated with Demodex infestation, whereas three variables (age, skin type, and skin disease) were found to be independent correlates. Students aged over 18 years had 22.1 times higher odds of Demodex infestation compared to those under 16 years and students aged 16-18 years also had 2.1 times higher odds compared to those aged 13-15 years. Odds of having a Demodex infestation for oily or mixed skin were 2.1 times those for dry or neutral skin. Students with a facial skin disease had 3.0 times higher odds of being infested with Demodex compared to those without. The inception rate of students with facial dermatoses increased in parallel with increasing mite count. The inception rates were 21.3%, 40.7%, 59.2%, and 67.7% in the negative, mild, moderate, and severe infestation groups, respectively ( χ=60.6, P<0.001). Specifically, the amount of infested mites and inception rate of acne vulgaris were positively correlated ( R=0.57, moderate infestation odds ratio (OR)=7.1, severe infestation OR=10.3). It was concluded that Demodex prevalence increases with age, and Demodex presents in nearly all adult human. Sebaceous hyperplasia with oily or mixed skin seems to favour Demodex proliferation. Demodex infestation could be associated with acne vulgaris. The CTP is a good sampling method for studies of Demodex prevalence. [ABSTRACT FROM AUTHOR]