Investigation of Microstructure and Wear Properties of Precipitates-Strengthened Cu-Ni-Si-Fe Alloy.

Based on multi-component alloys using precipitation hardening, a Cu-Ni-Si-Fe copper alloy was prepared and studied for hardness, electrical conductivity, and wear resistance. Copper Nickel Silicon (Cu-Ni-Si) intermetallic compounds were observed as precipitates, leading to an increase in mechanical and physical properties. Further, the addition of Fe was discussed in intermetallic compound formation. Moreover, microstructures, age hardening, and dry sliding wear resistances of the present alloy were analyzed and compared with C17200 beryllium copper. The results showed that the present alloy performed extraordinarily, with 314 HV in hardness and 22.2 %IACS in conductivity, which is almost similar to C17200 alloy. Furthermore, the dry sliding wear resistance of the present alloy was 2199.3 (m/MPa·mm3) at an ambient temperature, leading to an improvement of 208% compared with the C17200 alloy.

Edge-dislocation-induced ultrahigh elevated-temperature strength of HfMoNbTaW refractory high-entropy alloys.

Over 150 refractory high-entropy alloys (RHEAs) have been proposed in the last decade. Early alloys such as MoNbTaW and MoNbTaVW still show an unparalleled yield strength of approximately 400 MPa at 1600°C. However, RHEAs with even elevated high-temperature strength are necessary in aerospace vehicles and nuclear reactors to cope with advanced technology in the future. Here, solid-solution strengthening calculation and melting point prediction are combined to design single-phase RHEA for attaining ultrahigh strength at 1600°C. The results show that Hf0.5MoNbTaW and HfMoNbTaW alloys after fully homogeneous treatment at 2100°C for 2 h reveal a homogenous body-centered cubic phase. HfMoNbTaW alloy exhibits a yield strength of 571 MPa at 1600°C, much higher than that of MoNbTaVW (477 MPa). It is found that a plateau of strength occurs from 800°C to 1200°C, which is important for raising the strength level of RHEAs at high temperatures. This strengthening mechanism is explained with the change of deformation mode from screw to edge dislocations, which contributes an edge-dislocation-induced strength. A similar alloy design strategy could be applied to develop more RHEAs with an ultrahigh strength level.

Unusual presentation of linear wrist blisters associated with hereditary angioedema: The first case report in Taiwan.

Hereditary angioedema (HAE) is an autosomal dominant disease characterized clinically by recurrent episodes of swelling in the tissues of the extremities, face, abdomen, and respiratory tract. It is most often caused by C1 esterase inhibitor (C1 INH) gene mutation. This swelling may lead to bradykinin release, resulting in recurrent, paroxysmal, painful angioedema. Blister formation is an uncommon cutaneous manifestation of HAE. Herein, we report a case of a patient with HAE who developed linear wrist blisters on her skin, with swelling, as a rare complication of HAE. She was treated with attenuated androgens (Danazol) for two weeks at our clinic, after which the blisters showed dramatic improvement. To date, only a few HAE cases have been reported across the world. Therefore, it is important to focus on and recognize the development of edema blisters as a flare of HAE, which could consequently avoid unnecessary dermatological diagnostic workup and treatment.

A novel weighted distance threshold method for handling medical missing values.

Data in the medical field often contain missing values and may result in biased research results. Therefore, the objective of this work is to propose a new imputation method, a novel weighted distance threshold method, to impute missing values. After several experiments, we find that the proposed imputation method has the following benefits. (1) The proposed method with purity can reassign instances into the nearest class of the dataset, and the purity computation can filter outliers; (2) The proposed method redefines the degree of missing values and can determine attributes and instances relative to the missing values in different datasets; and (3) The proposed method need not set the k value of the nearest neighborhood because this study identifies the k value based on the best threshold to calculate purity to enhance the results of imputation. In addition, the distance threshold can adjust the optimal nearest neighborhood to estimate missing values. This study implements several experiments to compare the proposed method with other imputation methods using different missing types, missing degrees, and types of datasets. The results indicate that the proposed imputation method is better than the listed methods. Moreover, this study uses the stroke dataset from the International Stroke Trial (IST) to verify whether the proposed method can be effectively applied in practice, and the results show that the proposed method achieves 90% accuracy in the Stroke dataset.

Using an electro-microchip, a nanogold probe, and silver enhancement in an immunoassay.

This paper presents a novel immunoassay that uses an electro-microchip to detect the immuno-reaction signal, gold nanoparticles (ANPs) as a label of antigen or antibody and as a catalyst for silver precipitation, and the silver enhancement reaction to magnify the detection signal. This study is based on the direct immunoassay (two-layer format) and the sandwich immunoassay (three-layer format). The ANPs were introduced into the electro-microchip by the specific binding of the antibodies-ANPs conjugates and then were coupled with silver enhancement to produce black spots of silver metal. The silver precipitation constructs a "bridge" between two electrodes of the electro-microchip allowing electrons to pass. The variation of impedance can be easily measured with a commercial LCR meter. Various gap sizes (20, 50, 100, and 200 microm) of the electrodes of electro-microchips were designed for the sensitivity study. The experimental data show that a chip with a 20microm gap has the highest sensitivity. There was a significant difference in impedance between the experiment sample and the negative control after 10 min of reaction time. The proposed method requires less time and fewer steps than the conventional enzyme-linked immunosorbent assay (ELISA). In addition, it shows a high detection sensitivity (10 microg/mL of 1st antibody (IgG) immobilized on slides and 1 ng/mL of antigen (protein A)). There is a clear distinction between the signal intensity and the logarithm of the sample concentration. The proposed new immunoassay method has potential applications in proteomics research and clinical diagnosis.