Brucellosis remains a major global public health concern, with B. melitensis and B. abortus being the primary causative agents in China. This study describes the development of a multiplex droplet digital PCR (ddPCR) assay for the simultaneous detection and differentiation of B. melitensis and B. abortus. The assay employs TaqMan probes targeting the bcsp31 gene (genus-specific), a transposase gene (B. melitensis-specific) and an autotransporter-associated beta strand repeat-containing protein gene (B. abortus-specific), each labeled with distinct fluorophores (FAM, HEX, ROX). The optimized assay exhibited no cross-reactivity with other pathogens and exhibited significantly higher sensitivity than both qPCR and conventional PCR, with detection limits as low as 2.54-3.11 copies/reaction. Repeatability was excellent, with intra- and inter-assay coefficients of variation below 9%. When validated on a panel of clinical nucleic acid samples, the ddPCR assay showed strong agreement with qPCR (kappa = 0.85), with a sensitivity of 100% (79.42%~100%, 95%CI) and specificity of 95.96% (92.08%~99.84%, 95%CI). These findings establish the multiplex ddPCR as a rapid, sensitive, and highly specific diagnostic platform that improves brucellosis detection accuracy and supports targeted control strategies.

This study systematically investigates the deformation behavior of Ni, Ni5W, and Ni9W alloys during tensile testing accompanied by electron backscatter diffraction (EBSD) analysis. During the plastic deformation stage, the loss of EBSD signals at grain boundaries is significantly influenced by the direction of tensile loading. Grain boundaries perpendicular to the tensile direction are prone to strain localization but do not typically result in the loss of EBSD signals. In contrast, grain boundaries parallel to the tensile direction frequently show EBSD signal loss. Further analysis indicates that, with increasing deformation, the grain behavior in Ni, Ni5W, and Ni9W samples diverges into two main trends: one trend involves grains rotating towards a low Schmid factor orientation, which effectively resists dislocation slip and results in the formation of specific texture; the other trend maintains a high Schmid factor orientation, aligns with dislocation slip, and leads to texture evolution. In summary, this study enhances the understanding of the tensile deformation in face-centered cubic (FCC) metals, providing a theoretical foundation for optimizing the mechanical properties of metallic materials.

Given the limitation of the precipitation strengthening effect in high strength and high conductivity Cu-Cr alloy, work hardening emerges as a practical and effective means to further enhance its strength. The Cu-0.4 wt%Cr alloy underwent varying degrees of cold rolling between the solution and aging treatments. The results of TEM characterization indicate that plastic deformation enhances precipitation, which occurs earlier than recrystallization in the deformed Cu-0.4 wt%Cr alloy. Thermodynamic calculations indicate that the driving force for precipitation is several orders of magnitude higher than that for recrystallization, while the nucleation barrier for precipitation is several orders of magnitude lower than that for recrystallization. Thus, the delayed recrystallization relative to precipitation theoretically allows for the coexistence of precipitates and deformed microstructures. In the peak aging state, despite the presence of numerous deformed microstructures, conductivity is almost fully restored. After aging for 1 h, the synergistic strengthening effects of precipitation and work hardening result in the yield strength and tensile strength of the sample cold rolled 64 % reaching 384.6 MPa and 422.0 MPa, respectively.

In clinical applications, titanium and its alloy implants often suffer from corrosion, wear and tear, and poor biological activity. Surface modification is critical for improving the stability and bioactivity of titanium and its alloys. Zinc phosphate chemical conversion has received increasing attention as a promising technique for biomedical applications. However, the presence of a passive oxide layer on the TC4 (Ti6Al4V) surface poses challenges for conventional chemical conversion methods. In this study, the principle of galvanic coupling was utilized to facilitate the surface chemical transformation of TC4 titanium alloy, referred to as galvanic coupling phosphate chemical conversion (GCPCC). The effects of two types of galvanic coupling and different plastic deformations on the surface chemical transformation of TC4 titanium alloy at different temperatures were mainly investigated. The results indicate that the Ti/Fe multipoint coupling formed by magnetron sputtering during chemical transformation at 70 C-degrees significantly enhances the nucleation sites of hopeite (Zn-3(PO4)(2)& sdot;4H(2)O) and accelerates the nucleation rate. Compared with line-coupled conversion coatings, multipoint coupling GCPCC coatings exhibit superior uniformity and finer microstructure, and the thickness of the laths is significantly reduced from 5 to 10 mu m to less than 1 mu m. Moreover, the temperature exerts a substantial influence on the formation of conversion coatings. At 70 C-degrees, the GCPCC coating primarily comprises hopeite, while the coating resulting from chemical conversion treatment consists of both hopeite and an amorphous ZnP-like granular coating at 50 C-degrees.

Face-centered cubic (FCC) metals exhibit varying stacking fault energies (SFE), which predominantly lead to the development of copper-type and brass-type textures during extensive deformation rolling. However, the mechanism underlying the formation of brass-type textures remains poorly understood. This study identifies the significant role of Goss-oriented texture in driving the development of brass-type texture in nickel-based metals. Despite its importance, the Goss-oriented texture has often been overlooked in studies focusing on the rolling texture of FCC metals due to its relatively low occurrence. This investigation explores the formation of Gossoriented texture during the rolling process of nickel-based metals and its influence on microstructural deformation. Research indicates that the formation of Goss-oriented texture primarily arises from two mechanisms: dislocation slip and twinning deformation of copper-oriented grains. While dislocation slip minimally affects the microstructure during metal rolling, twinning deformation induces stress concentration and the initiation of shear bands. These factors subsequently influence dislocation slip in copper-oriented grains, ultimately leading to the formation of brass-type rolling texture.

In this study, CoCrFeNi high entropy alloy thin films were prepared on 304 stainless steel and single crystal Si substrates using the direct-current magnetron sputtering process under different bias voltages. The effects of these bias voltages on the film micrographs, phase structure, surface roughness, corrosion resistance, and mechanical characteristics of thin films were studied by a scanning electron microscope, transmission electron microscope, X-ray diffractometer, atomic force microscope, electrochemical workstation and nanoindentation tester, respectively. The results indicated that all films exhibited equiaxed nano-scale grains and developed a columnar structure. Fe, Co, Cr, and Ni were uniformly dispersed in all films and all films displayed face centered cubic solid solution (FCC). At a bias voltage of 0 V, the CoCrFeNi HEAs film formed a FCC single phase. With increasing bias voltage, the crystallinity decreased and then increased, reaching the worst crystalline state at bias voltage of -200 V due to the fact that the structure of the film was composed of FCC nanocrystalline and amorphous biphasic structure. Meanwhile, the surfaces of the film prepared at bias voltage of -200 V exhibited the densest structures and the least roughness, with grain sizes reaching a minimum value of approximately 10 nm. In addition, columnar grains of the film prepared at a bias voltage of -200 V displayed the densest state and had the least size, thus this film displayed the best corrosion resistance of a minimum value 1.51 x 10- 7 A/ cm2, a maximum hardness of approximately 11.18 f 0.2 GPa and a maximum elastic modulus of approximately 193 f 2.8 GPa. The passivation films of CoCrFeNi HEAs films were mainly composed of Cr2O3.

In this study, CrNiTiMo high-entropy alloys films were prepared on 304 stainless steel and silicon wafer substrates by direct current magnetron sputtering and the effects of bias voltages (0 to −200 V) on microstructure, chemical composition, hardness and corrosion resistance were investigated. The results showed that the surface of the CrNiTiMo HEAs films exhibited equiaxed nanoparticles and are composed of uniformly distributed Cr, Ni, Ti, and Mo elements. Meanwhile, the films developed a columnar structure and formed a biphasic structure with body-centered cubic solid solution and amorphous phases. The roughness decreased and then increased with increasing bias voltage, and the film deposited at −50 V had the lowest roughness (1.02 ± 01 nm), which also had a maximum hardness of approximately 9.52 ± 0.2 GPa and a maximum elastic modulus of approximately 187 ± 6 GPa. In addition, all films showed better corrosion resistance compared to 304 stainless steel substrates at 3.5 wt% NaCl solution. The corrosion current density (icorr) of the films decreased and then increased with increasing bias voltages and reached the lowest icorr of about 2.49 × 10−8A/cm2, indicating that the films deposited at a bias voltage of −50 V had the best corrosion resistance. These was attributed to the formation of the passivation films mainly composed of TiO2 and Cr2O3 and the improvement of the surface quality of the film as well as the refinement of the columnar structure and particles.

High strength and high conductivity Cu-0.67Cr-0.3Zr alloy was prepared by vacuum directional solidification equipment. The face centered cubic (FCC) and body centered cubic (BCC) Cr rich precipitations in Cu matrix were characterized by high resolution transmission electron microscopy. In the as cast and solution treated state, a large amount of coherent FCC Cr precipitates is uniformly distributed in the matrix. These FCC Cr precipitates are covered by close packed {111} crystal planes and presents regular morphology. Due to their small size and cube-cube orientation with the matrix, FCC Cr precipitates follows dislocation shearing mechanism, resulting in limited strengthening effect. After aging treatment, both incoherent ordered nearly spherical and incoherent rod-shaped BCC Cr precipitates were formed in the matrix. These incoherent precipitates always follow dislocation bypassing mechanism. Due to its small size and high-volume content, the spherical precipitation plays a major role in improving the strength of the alloy. On the contrary, the influence of rod-shaped precipitates on strength is minimal. According to the minimum free energy theory and local chemical potential equilibrium requirement, the precipitation with Kurdjumov-Sachs (K-S) orientation relationship tends to be rod-shaped extending along the direction of Cu [110] and Cr [111], while the precipitation with Nishiyama-Wassemann (N-W) orientation relationship tends to be nearly spherical.

有效防控动物疫病是实现畜牧业高质量发展的重要保障,也是扎实推进乡村产业振兴、保障多元化食物供给、拓宽农民致富渠道、提高农牧民生活品质的必然要求.本文梳理归纳了新中国成立以来我国动物疫病防控工作取得的四方面成效:成功消灭三大瘟疫,有效控制重大动物疫病,稳定控制部分人兽共患病,成功防范系列重大外来病;从动物疫病传染源、传播途径和易感动物等方面,分析了当前防控工作面临的风险与挑战;提出了坚持免疫与扑杀相结合、提高生物安全水平、严格调运监管、提升科技支撑力、精准实施宣传干预和强化兽医队伍等六方面工作建议,供行业参考.

【Objective】 This study was aimed to investigate the inter-group distribution, drug resistance characteristics and genetic relationships of carbapem-resistant Escherichia coli（CREC） strains from different poultry, so as to provide technical support for blocking the potential hazards of CREC.【Method】 A total of 1 131 cloacal swabs were collected from broilers, laying hens and waterfowls in Jiaodong area, and CREC strains were identified by selective isolation and culture, mass spectrometry identification, PCR,broth microdilution, multi-locus sequence typing（MLST） and whole genome sequencing（WGS）.【Result】 A total of 364 bla NDM gene positive CREC strains were isolated with a separation rate of 32.18% and the overall proportion of positive farms was 76.32%.The positive rates at both farm and individual levels of broilers were the highest（93.33% and 55.56% respectively）.All the strains from three types of poultry were multi-drug resistant.83.65% of the isolates were resistant to 8 or more classes of drugs simultaneously, and the resistance rate to most of the tested drugs was more than 80%.The multi-drug resistance in broilers was the most serious, followed by waterfowl and laying hens.45 whole-genome sequenced CREC strains carried 52 drug resistance genes in 12 classes within 4 kinds of bla NDM variants(mainly bla NDM-5 ,77.78%).The detection rates of specific drug resistant gene of CREC originated from three types of poultry were different.A total of 46 ST types were detected, with a diversity ratio of 44.23%.There were 82-71 307 SNPs among the CREC strains from three types of poultry, and the dominant ST types of different poultry were quite different.【Conclusion】 CREC that carrying bla NDM was widely prevalent in different poultry farms, especially in broiler farms, and the bla NDM-5 subtype was dominant.They were generally resistant to a variety of antimicrobial agents and carried a large number of drug-resistant genes, mainly plasmid transmission.CREC strains from three types of poultry showed diverse distribution, and the genetic relationship among most strains was quite far.It was suggested that surveillance and risk factors of CREC among different animals should be strengthened.

针对我国外来动物疫病(简称"外疫")传入风险高、病种多的现实,为提升外疫早期预警、快速诊断、应急处置能力,中国动物卫生与流行病学中心联合农业、卫生、海关、教育、科技等部门共10家单位共同承担了国家重点研发计划"重大动物源性病原体传入风险评估和预警技术研究"项目(项目编号:2017YFC1200500).

Porcine epidemic diarrhea (PED) is a highly contagious, intestinal infectious disease in pigs, characterized by severe diarrhea, vomiting and dehydration. PED is widely epidemic in China as well as in many eastern Asian and America countries, causing tremendous losses in pig industry. However, little was known about the disease frequency and the associated risk factors of PED in pig farms. A cross-sectional study was conducted to estimate the herd prevalence and to identify the potential risk factors of porcine epidemic diarrhea virus (PEDV) infection of pig farms (≥100 pigs) in Junan county, China. A two-stage random sampling strategy was adopted, and a total of 751 fecal samples from suckling piglets of 82 farms were collected and tested by RT-PCR and sequencing for PEDV. Meanwhile, information on the putative risk factors of PEDV infection of those farms were collected in forms of questionnaires, followed by a descriptive analysis, univariable and multivariable logistic regression analysis. The results showed that the herd-level true prevalence of PEDV infection of pig farms in Junan was 35.16 % (95 %CI: 22.91-53.89); there were two variables significantly associated with PEDV infection, which were 'having more than 1000 slaughter pigs per annum' (OR = 5.42, 95 %CI: 1.19-24.72), and 'Weaning at 21-25 days' old' (OR = 4.50, 95 %CI:1.25-16.20). The research suggested that PED was highly endemic in pig farms in Junan county; larger herd size and weaning at an earlier age were potential risk factors associated with PEDV infection in pig farms in Junan. This study set an example in the research on herd-level prevalence of PEDV infection and risk factors associated with PEDV infection, and the results were of practical significance for the future planning of prevention and control of PED in Junan or other areas of China.

依据世界动物卫生组织(WOAH)和联合国粮农组织(FAO)相关信息,系统梳理了全球食用动物、毛皮动物、伴侣动物、野生动物的新型冠状病毒(SARS-CoV-2)感染情况及其流行病学研究概况.全球动物感染SARS-CoV-2时有发生,且发生率呈上升趋势;食用动物对SARS-CoV-2具有抵抗力,而毛皮动物、伴侣动物以及多种野生动物对SARS-CoV-2易感.WOAH和FAO分析认为:当前人间SARS-CoV-2国际大流行的主要驱动力是人与人之间的传播,而动物对其传播不起重要作用;SARS-CoV-2在动物种群中传播可能会促进新病毒变种的出现,使新冠疫情防控形势复杂化.WOAH不建议对动物及其产品(生貂皮除外)设置SARS-CoV-2相关贸易限制措施,但同意成员基于风险分析实施相关卫生措施;FAO呼吁采取措施,降低SARS-CoV-2在人与野生动物之间的传播风险,进而降低病毒变异风险;现已有国家禁止水貂养殖,限制易感动物进口.

Background The H5 subtype avian influenza virus (AIV) has caused huge economic losses to the poultry industry and is a threat to human health. A rapid and simple test is needed to confirm infection in suspected cases during disease outbreaks. Methods In this study, we developed a reverse transcription recombinase-aided amplification (RT-RAA) assay for the detection of H5 subtype AIV. Assays were performed at a single temperature (39 °C), and the results were obtained within 20 min. Results The assay showed no cross-detection with Newcastle disease virus or infectious bronchitis virus. The analytical sensitivity was 10 3 RNA copies/μL at a 95% confidence interval according to probit regression analysis, with 100% specificity. Compared with published reverse transcription quantitative real-time polymerase chain reaction assays, the κ value of the RT-RAA assay in 420 avian clinical samples was 0.983 ( p < 0.001). The sensitivity for avian clinical sample detection was 97.26% (95% CI, 89.56–99.52%), and the specificity was 100% (95% CI, 98.64–100%). Conclusions These results indicated that our RT-RAA assay may be a valuable tool for detecting H5 subtype AIV.

Commercial high strength and high electrical conductivity Cu-0.67Cr-0.3Zr alloy was directionally solidified and subsequent aged. The specific strengthening mechanism of FCC and BCC structured chromium precipitations was discussed in detail. The strengthen effect of FCC Cr precipitation with a size less than 35 nm follows shear strengthening mechanism, while that of BCC Cr precipitation with size greater than 1.4 nm follows non-shear strengthening mechanism. After aging treatment, the yield strength of the alloy with a solidification rate of 50 μm/s increases from about 140 to 205 MPa, which is due to the transformation of Cr precipitation from FCC to BCC. Besides, the matrix purification caused by phase transformation increases the electrical conductivity. In addition, the wear resistance of the alloy is also improved with the increase in strength. These excellent properties make the alloy have the potential to be competent as the high-speed railway contact lines.

The chemical short-range order (CSRO) and grain size affect the strength and ductility of high-entropy alloys (HEAs). However, their superposition effect has not yet been studied, limiting further improvement in performance. In this work, we examined the synergistic effect of the CSRO and grain size on the tensile properties of CoCrFeMnNi at room temperature by conducting atomic simulations, because performing an experimental investigation on the formation and movement of dislocations is difficult. The results showed that the preferable locations of the various elements were different. Cr and Mn were preferentially distributed on the grain boundary, Co and Fe were enriched inside the grain, and Ni accumulated in the transition zone from the grain boundary to the intragranular region. In addition, increasing the CSRO appropriately can optimize the density and distribution of dislocations, simultaneously enhancing the strength and ductility of HEAs. Furthermore, an inverse Hall-Petch relation was observed in the system without the CSRO. The simulation computation revealed that the critical grain size that induces the inverse Hall-Petch relation is approximately 13.1 nm. However, the presence of the CSRO eliminates the inverse Hall-Petch relation.

China launched a H7N9 vaccination program in poultry, starting from the Guangxi and Guangdong provinces in July 2017, followed by other provinces in September 2017, as a response to a steep increase of H7N9 influenza human infections from September 2016. Since then, H5-H7 bivalent vaccine has been used in the nationwide avian influenza compulsory vaccination program to replace the existing H5N1 vaccine. However, the economic returns of the H7N9 vaccination program in China have never been adequately assessed. This study was designed to evaluate the economic value of the H7N9 vaccination program in Guangxi by assessing the benefits and costs of the program compared to not vaccinating against H7N9. A benefit-cost analysis (BCA) was undertaken to evaluate the adoption of a vaccination program against H7N9 in each of three consecutive years from July 2017 to June 2020 with the baseline scenario (the absence of H7N9 vaccination in the 12-month period July 2016 to June 2017). Both animal and public health perspectives were included in the BCA framework and took account of both the private and public sectors. Benefit-Cost Ratio (BCR) of the three-year H7N9 vaccination program was 18.6 (90 %PI: 15.4; 21.8), and total Net Present Values reached to CNY 1.63 billion (90 %PI: 1.37 billion; 1.89 billion). The extra revenue generated by the yellow broiler industry comprised 93.8 % of the total benefits after adoption of H7N9 vaccination program in Guangxi. While cost-savings in public health and animal health expenditure avoided were 3.6 % and 2.6 %, respectively. Total costs arising from adoption of the revised vaccination program over the three years were CNY 12.46 million (90 %PI: 11.49 million; 14.14 million), CNY 34.87 million (90 %PI: 31.88 million; 40.06 million), and CNY 44.28 million (90 %PI: 39.66 million; 52.27 million), respectively. Sensitivity analysis found the yellow broiler wholesale prices contributed 97.7 % of the variance of the total NPV of three vaccination years. The study results demonstrate the significant economic advantage of implementing a vaccination program against H7N9 in Guangxi. It also offers a new set of evidence to China's H7N9 vaccination policy and debates around economic values of conducting routine avian influenza vaccination.

为掌握新疆、青海、甘肃、四川和西藏等西部5省区农牧民包虫病防控相关知识、态度和行为("知信行"),分析影响"知信行"水平的关键因素,对1213名农牧民进行问卷调查,用百分比描述"知信行"的每个条目,采用t检验或方差分析,比较不同人群的"知信行"水平差异.结果显示:西部5省区农牧民对包虫病防控相关知识的知晓率为57.0％,其中感染途径知晓率最低,为30.8％;55.6％的农牧民对包虫病防控持有积极态度,68.3％的农牧民对包虫病防控有较好的行为习惯.当地农牧民获取包虫病防治知识的途径多来自医生和传统宣传资料,分别占60.7％和48.2％,未来还希望通过电视、广播和网络等大众媒体获取.青海省农牧民以及文化程度初中及以上、民族为汉族的农牧民具有较高的认知水平.结果表明,西部5省区农牧民对包虫病的认知水平较低,获取相关信息途径较为单一.建议加大宣传力度,突出包虫病源头防控;利用当前主流新媒体,丰富宣传方式,使宣传内容、载体更加契合西部少数民族地区的生活和文化习惯,切实推进农牧民防疫意识和自我防护意识的提升.

In present research, the phase evolution and mechanical properties of FeCoCrNiSix high-entropy alloys were investigated by using different testing techniques. The results showed that Si element can promote the formation of BCC phase and had a significant effect on the micro-hardness and wear resistance of alloys. The micro-hardness of HEAs increased from 89.52 HV to 653.71 HV and the depth of the wear track decreased from 22.139 mu m to 5.292 mu m with the addition of Si element. When x was equal to 1 (FeCoCrNiSix), the alloy possessed the highest micro-hardness and best wear resistance. Moreover, the wear mechanism was transformed into abrasive wear according to the wear tracks measurements due to the addition of Si elements. (C) 2020 Elsevier B.V. All rights reserved.