Discrimination the geographical origin of Yanchi Tan Lamb with different muscle sections by stable isotopic ratios and elemental profiles

In the study, lamb, feed and soil samples were collected from three regions of China in the year 2017 and 2018. The δ¹³C and δ¹⁵N values in lamb (defatted dry mass and lipids) and grass and the contents of nine elements in lamb, grass and soil were determined. The results indicated that except for Fe, Zn and Rb, most variables of lamb showed significant differences among two or three regions, and the contents of Fe, Sr and Cs showed significant differences between two years, and the contents of Cu and Zn showed significant differences among different muscle sections. Besides, significant correlations were found for δ¹³C between defatted lamb and lipid (r² = 0.973, P < 0.05) and for the element contents between lamb and soil. Finally, four key variables δ¹³C, δ¹⁵N, Sr and Mo were selected through stepwise canonical discriminant analysis with the cross-validation correct classification rate of 99.1%.     

一种牵引供电系统地震灾害风险评估方法

电气化铁路牵引供电系统的安全可靠至关重要,然而部分地区牵引供电系统面临地震灾害威胁.为有效评估地震灾害下牵引供电系统的风险水平,该文首先采用蒙特卡洛方法模拟地震灾害并得到表征地震动强度的峰值加速度指标;然后通过分析系统主接线,建立系统的有向图逻辑模型,在此基础上,考虑系统停运概率、关键设备损失以及停运时间等因素定义风险指标,提出牵引供电系统地震灾害风险评估方法;最后选取西南地区某规划中的电气化铁路牵引供电系统作为算例,评估系统在地震灾害下的风险.结果表明,该文算法能有效量化牵引供电系统在地震灾害下的风险水平,可实现震后快速损失评估,为灾后抢险、应急物资调配提供参考,也可为牵引供电系统抗震规划提供理论依据.     

堤坝隐患无损探测技术综述

堤坝无损探测技术包括物探和化探方法,已广泛地应用于渗漏、洞穴等堤坝隐患探测.本文对各种探测方法的基本原理、优点、缺点、探测深度、应用条件和应用领域等进行系统的总结.最后总结影响堤坝隐患探测效果的三个因素:探测对象的复杂性、单一探测方法的不足和物探方法的局限性;并提出三点提高探测效果的建议.     

高能同步辐射光源逐束团束流位置测量电子学研制

基于高能同步辐射光源（HEPS）储存环，研制了一套逐束团束流位置测量（BPM）电子学系统，电子学的硬件部分由模拟信号采集板卡和数字信号处理板卡组成，软件部分由底层固件和顶层应用软件组成。系统的采样频率为500 MHz，带宽为1 GHz，对来自储存环BPM探头的4路模拟信号进行数字化，得到束团幅度数据，利用ZYNQ芯片计算出每个束团在真空管道中的位置。逐束团BPM电子学在实验室的测试结果为：输入信号峰峰值小于1.8 V时ADC通道非线性度小于1%，无杂散动态范围约60 dB，灵敏度系数取8.26 mm时位置分辨率优于10 μm，测试结果满足HEPS逐束团BPM的需求。     

Methylglyoxal: A newly detected and potentially harmful metabolite in the blood of ketotic dairy cows

Ketosis causes serious economic losses for the modern dairy industry because it is a highly prevalent metabolic disease among cows in high-producing herds during the transition period. Due to some striking similarities between diabetes in humans and ketosis in dairy cows, there is potential for the use of methylglyoxal (MGO)—commonly used in human diabetics—as a biomarker in dairy cattle. However, currently no data are available about the presence of MGO in the serum of dairy cattle or about the characteristics of its production or its potential contribution in the pathogenesis of ketosis. To determine the potential origin and pathway of formation of MGO, cows in different metabolic conditions [i.e., non-subclinically ketotic dairy cows in early lactation (n = 7), subclinically ketotic dairy cows in early lactation (n = 8), overconditioned dry cows (BCS >4.25, n = 6), and nonlactating heifers (n = 6)] were selected. Serum MGO concentrations were determined and correlated with indicators of the glucose and lipid metabolism and with haptoglobin (Hp) as an inflammatory marker. The serum MGO concentrations in subclinically ketotic cows (712.60 ± 278.77 nmol/L) were significantly greater than in nonlactating heifers (113.35 ± 38.90 nmol/L), overconditioned dry cows (259.71 ± 117.97 nmol/L), and non-subclinically ketotic cows (347.83 ± 63.56 nmol/L). In serum of lactating cows, concentrations of glucose and fructosamine were lower than in heifers and were negatively correlated with MGO concentrations. Even so, concentrations of metabolic and inflammatory markers such as dihydroxyacetone phosphate, nonesterified fatty acids, β-hydroxybutyrate, acetone, and Hp were remarkably higher in subclinically ketotic cows compared with nonlactating heifers; these metabolites were also positively correlated with MGO. In human diabetics elevated MGO concentrations are stated to originate from both hyperglycemia and the enhanced lipid metabolism, whereas higher MGO concentrations in subclinically ketotic cows were not associated with hyperglycemia. Therefore, our data suggest MGO in dairy cows to be a metabolite produced from the metabolization of acetone within the lipid metabolization pathway and from the metabolization of dihydroxyacetone phosphate. Furthermore, the highly positive correlation between MGO and Hp suggests that this reactive compound might be involved in the proinflammatory state of subclinical ketosis in dairy cows. However, more research is needed to determine the potential use of MGO as a biomarker for metabolic failure in dairy cows.     

Bacterium‐Templated Polymer for Self‐Selective Ablation of Multidrug‐Resistant Bacteria

The recognition and inactivation of specific pathogenic bacteria remain an enormous scientific challenge and an important therapeutic goal. Therefore, materials that can selectively target and kill specific pathogenic bacteria, without harming beneficial strains are highly desirable. Here, a material platform is reported that exploits bacteria as a template to synthesize polymers with aggregation‐induced emission (AIE) characteristic by copper‐catalyzed atom transfer radical polymerization for self‐selective killing of the bacteria that templates them with no antimicrobial resistance. The bacteria‐templated polymers show very weak fluorescence in aqueous media, however, the fluorescence is turned on upon recognition of the bacteria used as the template to synthesize the polymer even at a low concentration of 600 ng mL^?1. Moreover, the incorporated AIE fluorogens (AIEgens) can act as an efficient photosensitizer for reactive oxygen species (ROS) generation after bacteria surface binding, which endows the templated polymers with the capability for selective bacterial killing. The bacterium‐templated synthesis is generally applicable to a wide range of bacteria, including clinically isolated multidrug‐resistant bacterial strains. It is envisioned that the bacterium‐templated method provides a new strategy for bacteria‐specific diagnostic and therapeutic applications.     

西安脉冲堆反应性测量空间效应修正方法研究

反应性是反应堆重要的物理参数，在西安脉冲堆上增加反应性实时监测功能，能够为操纵员提供反应性实时大小和变化趋势，有利于其安全运行。逆动态方法以其实时性好、能测量任意反应性引入而被广泛应用于反应性测量，但由于控制棒的移动会导致中子注量率空间分布前后不一致，而出现偏差。本文对逆动态方法和静态空间效应因子进行了理论分析，给出了相应的计算方法；以西安脉冲堆为研究对象，使用蒙特卡罗（MCNP）程序计算了探测器三维空间的响应函数，同时计算了归一化节块功率密度，由此得到静态空间效应因子；最后在脉冲堆上进行了不同棒速下插控制棒实验，处理实验数据得到控制棒积分价值曲线。结果表明，进行空间效应修正是必要的，经修正后计算得到的控制棒价值曲线更稳定，计算结果与真实值误差更小。      

Sparse recovery formulation for secure distance-based localization in the presence of cheating anchors

Wireless Networks - Secure localization in the presence of cheating anchors is a critical issue in wireless sensor networks, where compromised anchors attempt to falsify the measured distances in...     

Effect of lactose content on dielectric properties of whole milk and skim milk

Dielectric properties (dielectric constant ε′ and dielectric loss factor ε′′) of whole milk and skim milk with the lactose content of 4.56–6.44% and 4.57–6.47%, respectively, were measured over the frequency range of 20–4500 MHz at 25 °C using a vector network analyzer. The results showed that ε′ decreased with increasing frequency, and ε′′ changed with V shape and its minimum was noted at about 2000 MHz. Whole milk had lower dielectric properties than skim milk at almost same lactose content and a given frequency. ε′ had weak positive linear relationship with lactose content for whole milk, but had negative linear relationship for skim milk. No matter for which milk, ε′′ had very good negative linear relationship with lactose content below 1000 MHz and had good positive linear relationship above 2300 MHz. The study provides information on developing rapid lactose detector for milk in future.     

Solution-Processed Organic Solar Cells with High Open-Circuit Voltage of 1.3 V and Low Non-Radiative Voltage Loss of 0.16 V

Compared with inorganic or perovskite solar cells, the relatively large non-radiative recombination voltage losses (ΔV_non-rad) in organic solar cells (OSCs) limit the improvement of the open-circuit voltage (V_oc). Herein, OSCs are fabricated by adopting two pairs of D–π–A polymers (PBT1-C/PBT1-C-2Cl and PBDB-T/PBDB-T-2Cl) as electron donors and a wide-bandgap molecule BTA3 as the electron acceptor. In these blends, a charge-transfer state energy (E_CT) as high as 1.70–1.76 eV is achieved, leading to small energetic differences between the singlet excited states and charge-transfer states (ΔE_CT ≈ 0.1 eV). In addition, after introducing chlorine atoms into the π-bridge or the side chain of benzodithiophene (BDT) unit, electroluminescence external quantum efficiencies as high as 1.9 × 10⁻³ and 1.0 × 10⁻³ are realized in OSCs based on PBTI-C-2Cl and PBDB-T-2Cl, respectively. Their corresponding ΔV_non-rad are 0.16 and 0.17 V, which are lower than those of OSCs based on the analog polymers without a chlorine atom (0.21 and 0.24 V for PBT1-C and PBDB-T, respectively), resulting in high V_oc of 1.3 V. The ΔV_non-rad of 0.16 V and V_oc of 1.3 V achieved in PBT1-C-2Cl:BTA3 OSCs are thought to represent the best values for solution-processed OSCs reported in the literature so far.