Bio-inspired functional surface fabricated by electrically assisted micro-embossing of AZ31 magnesium alloy

Developing bio-inspired functional surfaces on engineering metals is of extreme importance, involving different industrial sectors, like automotive or aeronautics. In particular, micro-embossing is one of the efficient and large-scale processes for manufacturing bio-inspired textures on metallic surfaces. However, this process faces some problems, such as filling defects and die breakage due tocsize effect, which restrict this technology for some components. Electrically assisted micro-forming has demonstrated the ability of reducing size effects, improving formability and decreasing flow stress, making it a promising hybrid process to control the filling quality of micro-scale features. This research focuses on the use of different current densities to perform embossed micro-channels of 7 um and sharklet patterns of 10 um in textured bulk metallic glass dies. These dies are prepared by thermoplastic forming based on the compression of photolithographic silicon molds. The results show that large areas of bio-inspired textures could be fabricated on magnesium alloy when current densities higher than 6 A/mm2 (threshold) are used. The optimal surface quality scenario is obtained for a current density of 13 A/mm2. Additionally, filling depth and depth–width ratio nonlinearly increases when higher current densities are used, where the temperature is a key parameter to control, keeping it below the temperature of the glass transition to avoid melting or an early breakage of the die.Peer ReviewedPostprint (published version

Size effect on the springback of CuZn37 brass foils in tension and micro W-bending

With the ever-increasing demands on miniaturization, the requirement on good forming quality and high dimensional accuracy of micro parts is dramatically motivated. As a decisive factor affecting the accuracy of micro-bent parts, the springback is significantly influenced by size effects. In order to explore size-effect associated springback behaviour and evaluate the forming quality of micro-bent parts, an experimentally-based investigation on the influence of foil thickness, grain size and their interactive effect on the springback behaviour of CuZn37 brass foils with different thicknesses and grain sizes was carried out. The experimental results obtained via micro tensile tests revealed that the yield strength, Young’s modulus and elongation had a close correlation with the thickness to average grain size ratio. A micro W-bending process was used to perform the bending tests. Both springback and negative springback phenomena were observed. It was found that how size effects may influence the amount of springback would depend on the springback behaviours, e.g. positive springback or negative sprinback, etc. In addition, scatter phenomenon of the springback behaviour was analyzed quantitatively. An increased scatter was observed for the 50 μm thick specimens when the thickness to average grain size decreased, whereas an inverse tendency of the decreased scatter of the negative springback was found for the 75 and 100 μm thick specimens with increase of the grain size. Finally, forming quality of the W-shaped micro-bent parts was assessed

Peste des Petits Ruminants Virus in Tibet, China

Serologic and molecular evidence indicates that peste des petits ruminants virus (PPRV) infection has emerged in goats and sheep in the Ngari region of southwestern Tibet, People’s Republic of China. Phylogenetic analysis confirms that the PPRV strain from Tibet is classified as lineage 4 and is closely related to viruses currently circulating in neighboring countries of southern Asia

Genetic variants, pathophysiological pathways, and oral anticoagulation in patients with hypertrophic cardiomyopathy and atrial fibrillation

Atrial fibrillation (AF) is commonly prevalent in patients with hypertrophic cardiomyopathy (HCM). However, whether the prevalence and incidence of AF are different between genotype-positive vs. genotype-negative patients with HCM remains controversial. Recent evidence has indicated that AF is often the first presentation of genetic HCM patients in the absence of a cardiomyopathy phenotype, implying the importance of genetic testing in this population with early-onset AF. However, the association of the identified sarcomere gene variants with HCM occurrence in the future remains unclear. How the identification of these cardiomyopathy gene variants should influence the use of anticoagulation therapy for a patient with early-onset AF is still undefined. In this review, we sought to assess the genetic variants, pathophysiological pathways, and oral anticoagulation in patients with HCM and AF

A novel triplex real-time PCR assay for the differentiation of lumpy skin disease virus, goatpox virus, and sheeppox virus

IntroductionThree members of Capripoxvirus (CaPV) genus, including lumpy skin disease virus (LSDV), goatpox virus (GTPV), and sheeppox virus (SPPV), are mentioned as notifiable forms by World Organization for Animal Health. These viruses have negatively impacted ruminant farming industry worldwide, causing great economic losses. Although SPPV and GTPV cause more severe clinical disease in only one animal species, they can transfer between sheep and goats. Both homologous and heterologous immunization strategies are used to protect animals against CaPVs. However, development of accurate and rapid methods to distinguish these three viruses is helpful for the early detection, disease surveillance, and control of CaPV infection. Therefore, we developed a novel triplex real-time PCR (qPCR) for the differentiation of LSDV, GTPV, and SPPV.MethodsUniversal primers were designed to detect pan-CaPV sequences. Species-specific minor groove binder (MGB)-based probes were designed, which were labeled with FAM for LSDV, HEX for GTPV, and ROX for SPPV. The sensitivity, specificity, reproducibility, and ability of detecting mixed infections were evaluated for the triplex qPCR. Further, 226 clinical samples of the infection and negative controls were subjected to the triplex qPCR, and the results were verified using PCR-restriction fragment length polymorphism (PCR-RFLP) and sequencing methods for PRO30 gene.ResultsThe triplex qPCR could successfully distinguish LSDV, GTPV, and SPPV in one reaction, and the assay sensitivity was 5.41, 27.70, and 17.28 copies/μL, respectively. No cross-reactivity was observed with other viruses causing common ruminant diseases, including des petits ruminants virus, foot-and-mouth disease virus, bluetongue virus, ovine contagious pustular dermatitis virus, infectious bovine rhinotracheitis virus, and bovine viral diarrhea-mucosal disease virus. Inter-and intra-assay variabilities were < 2.5%. The results indicated that the triplex qPCR was highly specific, sensitive, and reproducible. Simulation experiments revealed that this assay could successfully distinguish two or three viruses in case of mixed infections without any cross-reaction. For clinical samples, the results were completely consistent with the results of PCR-RFLP and sequencing. This demonstrated that the assay was reliable for clinical application.DiscussionThe triplex qPCR is a robust, rapid, and simple tool for identifying various types of CaPV as it can successfully distinguish LSDV, GTPV, and SPPV in one reaction. Furthermore, the assay can facilitate more accurate disease diagnosis and surveillance for better control of CaPV infection

RNA interference in Lepidoptera: an overview of successful and unsuccessful studies and implications for experimental design

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Investigation of the Size Effects on the Elongation of Ti-2.5Al-1.5Mn Foils with Digital Image Correlation Method

The increasing demand for parts with a large specific surface area such as fuel panels has put forward higher requirements for the plasticity of foils. However, the deformation characteristics of foils is hard to be illustrated in-depth due to their very short deformation process. In this paper, the digital image correlation method was applied to investigate the influence of size effect on the elongation of Ti-2.5Al-1.5Mn foils. The results showed that the elongation of Ti-2.5Al-1.5Mn foils increased with the decrease in the ratio of thickness-to-grain diameter (t/d value). Then, the macro deformation distribution of foils was analyzed, combined with their microstructure characteristics, and it was found that the increasing influence of individual grain heterogeneity leads to the earlier formation of a concentrated deformation zone, which changes the deformation mode of foils. The concentrated deformation increases with the decrease in t/d value, thus dominating the trend of the foil elongation. Furthermore, the homogeneous deformation and concentrated deformation can be divided into two different zones by a certain critical t/d value. These results provide a basis for understanding and further exploration of the deformation behavior of titanium foils

Friction related size-effect in microforming – a review

This paper presents a thorough literature review of the size effects of friction in microforming. During miniaturization, the size effects of friction occur clearly. The paper first introduces experimental research progress on size effects of friction in both micro bulk and sheet forming. The effects of several parameters are discussed. Based on the experimental results, several approaches have been performed to develop a model or functions to analyse the mechanism of size effects of friction, and simulate the micro deep drawing process by integrating them into an FE program. Following this, surface modification, e.g. a DLC film and a micro structure/textured surface, as a method to reduce friction are presented. Finally, the outlook for the size effect of friction in the future is assessed, based on the understanding of the current research progress