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Spiking Neural Networks (SNNs) can closely mimic the biological neural network systems. Recently, the SNNs have been developed in hardware circuits to emulate the time encoding and information-processing aspects of the human brain in real-time. However, the hardware SNN systems are suffering from large hardware resource consumption due to the high complexity of computational units. In this paper, a novel hardware SNN system based on stochastic computing is proposed to address this problem. Pair-based spiking-timing-dependent plasticity, coupled with integrate-and-fire neurons are employed to design the SNN. Stochastic computing can simplify the computational components of multipliers, adders, and subtractors in conventional hardware SNNs, hence reduce the hardware resource cost. Experimental results show that compared with the state-of-the-art approaches the proposed SNN system reduces the resource consumption by 58.0% (especially registers by ≥ 65.6%). In the meantime, the maximum normalized root mean square error between the proposed hardware and others is only 0.0097, which can maintain the behaviours of SNN. This work provides a beneficial alternative to the large-scale hardware SNN implementations. [ABSTRACT FROM AUTHOR]

Wire and arc additive manufacturing (WAAM) has a high deposition rate, high material utilization, and compact structure, so it is especially suitable for low-cost, high-efficiency, and fast near-net-shape manufacturing of large-scale complex parts. However, in the WAAM process, many challenges limiting the quality and performance of the deposited layers, such as the WAAM process options and material selections limiting deposition performance and microstructure, manufacturing defects weakening the quality of the deposited layer, and the difficulty in predicting the quality and the performance. This paper outlines the challenges of WAAM, summarizes the challenges of material selections and processing methods, improving microstructure and performance, defect monitoring and improvement, simulation technology and artificial intelligence technology introducing predictive WAAM, and finally analyzes its development trends. [ABSTRACT FROM AUTHOR]

Studying the effects of key processing parameters during the actual production of aluminum alloys produced by cold metal transfer (CMT) welding on solidification cracks is pivotal to reducing their occurrence and greatly improving the quality of the products. In this work, a mathematical model based on the response surface methodology (RSM) is developed to analyze the influence of the multi-factor processing parameters of 4043 aluminum alloys produced by CMT welding on their susceptibility to solidification cracks and the optimization of the crack rate. The results show that the mathematical model is reliable and predictable. However, due to the complexity of the polynomial model, it is difficult for it to predict which parameters are prone to crack formation. After calculating the RSM, it is found that wire feeding speed and wire withdrawal are more likely to cause solidification cracks. Furthermore, the processing parameters are optimized by minimizing the susceptibility to solidification cracks. Consequently, a visual parameter map with crack-free curve boundaries is obtained and the crack-free area is calculated to facilitate operation. [ABSTRACT FROM AUTHOR]

The Yangtze River Delta white goat is a unique goat species that can produce superior-quality brush hair. The formation of superior-quality brush hair cannot occur without goat hair follicle stem cell differentiation. However, knowledge regarding the regulatory role of miR-149-5p in hair follicle stem cell differentiation is limited. Here, we found that miR-149-5p is widely expressed in the tissues of Yangtze River Delta white goats, but its expression in the skin tissue of superior-quality brush hair goats is high compared to normal- quality goats. The functional studies showed that miR-149-5p overexpression markedly facilitated hair follicle stem cell differentiation, whereas inhibiting miR-149-5p inhibited hair follicle stem cell differentiation. These results more clearly elucidate the regulatory role of miR-149-5p in hair follicle stem cell growth. [ABSTRACT FROM AUTHOR]

Wire-arc additive manufacturing (WAAM) based on cold metal transfer (CMT) welding process has been used to fabricate Cu-6.5 wt.% Al alloy by simultaneously feeding two separate wires. The deformation behavior of as-fabricated Cu-6.5 wt.% Al alloy and heat-treated Cu-6.5 wt.% Al alloy under quasi-static (0.1 s−1) tension was investigated. The obtained tensile results show that the heat treatment can improve the mechanical properties. The enhancements of strength and ductility originate from the work-hardening capacity and fine grain due to solid solution strengthening. The TEM characterization of the samples has shown the existence of deformation twinning. The optical micrographs have shown that during the tensile process, cracks are first formed inside the large grains, and then the cracks propagate, which cause dendritic columnar structure are broken into fragments. [ABSTRACT FROM AUTHOR]

The Yangtze River Delta White Goat is the only goat breed in the world that can produce superior-quality brush hair. Previous studies have shown that some genes are expressed differentially in the skin tissues between the goats produced superior-quality and normal-quality brush hair. Studies also have shown that different gene play varied roles in regulating the proliferation and apoptosis of hair follicle stem cells. However, the biological function of MAP3K1 (mitogen-activated protein kinase kinase kinase 1) gene in hair follicle stem cells is not fully understood. This study aims to investigate the role of MAP3K1 knockdown during the proliferation and apoptosis of hair follicle stem cells. RT-qPCR and Western blot were used to detect mRNA gene and protein expression level, CCK-8 and EdU assays were used to detect cell proliferation, and cell cycle and apoptosis were detected by flow cytometry. The results showed that the MAP3K1 expression level was significantly higher in the skin tissue of produced superior-quality brush hair than that in produced normal-quality brush hair. Moreover, functional studies indicated that si-MAP3K1 significantly inhibits the proliferation of hair follicle stem cells that came from a superior goat and promotes its apoptosis. Based on aforementioned assays, we speculated that MAP3K1 might play a regulatory effect in superior-quality brush hair traits. [ABSTRACT FROM AUTHOR]

In this work, the cold metal transfer (CMT) welding technique was used to additive manufacture Cu-6.6%Al-3.2%Si alloy. A dual wire feeding approach was adopted to separately feed SAFRA CuSi3 wire and AlSi5-ER4043 wire into the molten pool. To overcome the defect of non-uniform sample height, the CMT welding head was used in the round-trip configuration to deposit the samples. The deposited samples were characterized for their (1) microstructure and (2) mechanical properties of hardness and tensile strength. Microstructural characterization was done using optical microscopy (OM), scanning electron microscopy and transmission electron microscopy. From the elemental analysis, the central region of the deposited layer was enriched in aluminum and depleted in silicon compared to the region at the border of the layer. Evaluation of the mechanical properties showed that the deposited samples had good strength and ductility. The addition of silicon and manganese effectively improved the hardness and tensile strength properties of the deposited alloy. [ABSTRACT FROM AUTHOR]

The authors describe an electrochemiluminescent (ECL) DNA biosensor that is based on the use of gold nanoparticles (AuNPs) modified with graphite-like carbon nitride nanosheets (g-CN NSs) and carrying a DNA probe. In parallel, nanoparticles prepared from gold-platinum (Au/Pt) alloy and carbon nanotubes (CNTs) were placed on a glassy carbon electrode (GCE). Once the g-CN NHs hybridize with DNA-modified AuNPs, they exhibit strong and stable cathodic ECL activity. The Au/Pt-CNTs were prepared by electrochemical deposition of Au/Pt on the surface of the CNTs in order to warrant good electrical conductivity. On hybridization of immobilized capture probe (S), target DNA (S) and labeled signal probe (S), a sandwich-type DNA complex is formed that produces a stable ECL emission at a typical applied voltage of −1.18 V and in the presence of peroxodisulfate. Under optimized conditions, the method has a response to target DNA that is linearly related to the logarithm of its concentration in the range between 0.04 f. and 50 pM, with a 0.018 f. detection limit. [ABSTRACT FROM AUTHOR]

A paper-based portable and disposable cyto-device was fabricated for the purpose of detecting cancer cells and in-situ screening of anticancer drugs. The device was prepared as follows: (a) Au@Pd paper electrodes were prepared by growing Au@Pd nanoparticles on cellulose; (b) the aptamer against MCF-7 cells was immobilized on the paper electrodes; (c) PtNi alloy particles were loaded with carbon dots to form a PtNi@C-dot composite acting as the ECL label, (d) concanavalin A (Con A) was labeled with the ECL label and then dropped on sensor surface carrying cancer cell. Con A can specifically recognize the mannose on the cancer cell surface. The assay is performed in the following way: (1) The aptamer-modified electrode is placed in a solution containing MCF-7 cancer cells; (2) buffer containing peroxodisulfate is added; (3) a potential sweep (from −0.5 to −1.8 V) is applied to the electrode, and ECL intensity is recorded. ECL intensity is related to the number of captured MCF-7 cells in the 480 to 2.0 × 10 cells⋅mL‾ concentration range. The electrode was applied to design a screening method for anti-cancer drugs. This is accomplished by monitoring the number of apoptotic cancer cells after exposing the cells on the electrode to a drug-containing medium. In our perception, the method presented here has a wide range of potential applications in cancer diagnosis and treatment. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

We describe a paper-based chemiluminescence (CL) test for the determination of mercury(II) ion. A single-stranded DNA aptamer was first covalently immobilized via its amino groups to the hydroxy groups on the surface of cellulosic paper. The aptamer probes can capture Hg(II) ions due to their specific interaction with thymine. The CL reagent (a caboxylated phenylene-ethynylene referred to as P-acid) was immobilized on nanoporous silver (NPS@P-acid) and used a CL label on the aptamer. The stripe is then contacted with a sample containing Hg(II) ions and CL is induced by the addition of permanganate. CL intensity depends on the concentration of Hg(II) because Hg(II) increases the quantity of the P-acid-conjugated aptamer. The highly active surface of the NPS@P-acid composites results in an 8-fold higher CL intensity compared to the use of pure P-acid. This enables Hg(II) ion to be quantified in the 20 nM to 0.5 μM concentration range, with a limit of detection as low as 1 pM. This CL aptasensor is deemed to represent a promising tool for simple, rapid, and sensitive detection of Hg(II). [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A novel microfluidic paper-based chemiluminescence (CL) analytical device (μPAD) with high-throughput, rapid, stable, reusable point-of-care (POC) testing and quantitative response for DNA was designed. Sodium periodate was used to modify μPAD to covalently immobilize capture DNA. The paper device was fabricated by a low-cost, simple, and rapid wax screen-printing method. The developed paper-based CL immunodevice, combined with a typical luminol-HO CL system, showed excellent analytical performance for the detection of DNA. Moreover, gold nanoparticles for signal DNA immobilization were used for signal-on CL assay of target DNA, which greatly improved the sensitivity. This study shows the successful integration of the μPAD and the CL method to afford an easy-to-use, inexpensive, and portable alternative for POC monitoring. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A molecular imprinted polymer (MIP) thin film for photoelectrochemical (PEC) sensing of lindane molecules was constructed by electropolymerizing o-phenylenediamine ( o-PD) monomer and lindane template molecule on titanium dioxide nanotubes. The resulting PEC sensors were characterized by scanning electron microscopy, ultraviolet (UV)-vis spectra and electrochemical impedance spectra. Clearly, the imprinted film showed high selectivity to lindane in our case. Under visible light irradiation, MIP film can generate the photoelectric transition from the highest occupied molecular orbital to the lowest unoccupied molecular orbital, delivering the excited electrons to the conduction band of titanium dioxide nanotubes. Simultaneously, it is believed that a positive charged hole (h) of MIP that took part in oxidation process was consumed to promote the amplifying photocurrent response. The MIP-based PEC sensor had an excellent specificity and could be successfully applied to the recognition and detection of lindane, indicating a promising application in handling with organochlorine pesticide. [ABSTRACT FROM AUTHOR]

Biofuel cells (BFCs) based on anodic oxidation and cathodic oxygen reduction represent an attractive alternative to self-powered devices. A glucose/oxygen BFC is described for monitoring glucose. It is making use of a piece of paper carrying a glucose oxidase (GOx) based bioanode, and a bilirubin oxidase (BilOx) based biocathode. The performance of the BFC is affected by the generation of H2O2, a byproduct of enzymatic glucose oxidation. Therefore, the removal of H2O2 is a crucial step in terms of BFC performance and stability. In addition, direct, unambiguous visual read-out is an ideal way to provide quantitative information. The colorimetric readout system described here is based on the consumption of undesired H2O2 and to convert the extent of energy generation into recognizable variations in color. As the H2O2 travels along the hydrophilic channel by capillary action, the formation of red gold nanoparticles from AuCl4− leads to the appearance of a red bar that provides distance-based information that can be read visually. The multiply readable information (maximum power density of BFC or visible distance) provides further choices for quantification. It also enhances reliability. The self-powered system based on the BFC exhibits excellent performance. Glucose can be determined by this method in the 1 to 50 mM concentration range. [ABSTRACT FROM AUTHOR]