Plasma albumin-to-globulin ratio before dry-off as a possible index of inflammatory status and performance in the subsequent lactation in dairy cows

The dry-off of dairy cows represents an important phase of the lactation cycle, influencing the outcome of the next lactation. Among the physiological changes, the severity of the inflammatory response can vary after the dry-off, and this response might have consequences on cow adaptation in the transition period. The plasma protein profile is a diagnostic tool widely used in humans and animals to assess the inflammatory status and predict the outcome of severe diseases. The albumin-to-globulin ratio (AG) can represent a simple and useful proxy for the inflammatory condition. In this study, we investigated the relationship between AG before dry-off and inflammation, metabolic profile, and performance of 75 Holstein dairy cows. Blood samples were collected from ?62 (7 d before dry-off) to 28 d relative to calving (DFC) to measure metabolic profile biomarkers, inflammatory variables, and liver function. Daily milk yield in the first month of lactation was recorded. Milk composition, body condition score, fertility, and health status were also assessed. The AG calculated 1 wk before dry-off (?62 DFC) was used to retrospectively group cows into tertiles (1.06 ± 0.09 for HI, 0.88 ± 0.04 for IN, and 0.72 ± 0.08 for LO). Data were subjected to ANOVA using the PROC MIXED program in SAS software. Differences among groups observed at ?62 DFC were almost maintained throughout the period of interest, but AG peaked before calving. According to the level of acute-phase proteins (haptoglobin, ceruloplasmin, albumin, cholesterol, retinol-binding protein), bilirubin, and paraoxonase, a generally overall lower inflammatory condition was found in HI and IN than in the LO group immediately after the dry-off but also after calving. The HI cows had greater milk yield than LO cows, but no differences were observed in milk composition. The somatic cell count reflected the AG ratio trend, with higher values in LO than IN and HI either before dry-off or after calving. Fertility was better in HI cows, with fewer days open and services per pregnancy than IN and LO cows. Overall, cows with high AG before dry-off showed an improved adaptation to the new lactation, as demonstrated by a reduced systemic inflammatory response and increased milk yield than cows with low AG. In conclusion, the AG ratio before dry-off might represent a rapid and useful proxy to evaluate the innate immune status and likely the ability to adapt while switching from the late lactation to the nonlactating phase and during the transition period with emphasis on early lactation.     

高密度聚乙烯装置循环气冷却器腐蚀原因分析及防护

针对高密度聚乙烯装置循环气冷却器在使用中存在的腐蚀问题进行分析。通过采用相应的防护办法,取得良好的效果。     

岩石冻融循环试验建议性方案探讨

岩石冻融循环试验是低温岩石力学基础性试验,其主要涉及冻融循环温度、冻融时长、循环次数等3个指标。但目前关于指标的选取,国内外的试验规程或相关学者研究成果,均未给出明确参考依据,对岩石冻融循环试验方案的确定造成较大困扰。本研究旨在明确各指标的确定办法,提出建议性岩石冻融循环试验方案。首先,展开国内外冻融循环试验方案的全面综述,指出目前冻融循环试验方案确定时所存在问题,并藉此明确冻融循环试验方案思路;接着,针对以上三大影响指标,通过设计室内岩石冻融循环试验,详细探讨冻融循环温度、冻融时长、循环次数对岩石物理、力学参数的影响,最终根据试验结果,明确出针对不同岩性、孔隙率所对应的建议性试验方案。本研究将为后期冻融循环指标选取及标准化试验方案建立提供技术借鉴。     

Evolution of Oxidative Values during Kinetic Studies on Olive Oil Oxidation in the Rancimat Test

A comparative study was carried out in order to evaluate the kinetics of the formation of a number of primary and secondary oxidation products during oxidation of olive oil in the Rancimat test at 100–130 °C. There were good correlations between the Rancimat index (OSI) and stability indices (IP) measured in the Rancimat test with no significant differences in kinetic parameters calculated from them. Mean values of the temperature coefficient, Q₁₀ number, activation energy (E_a), frequency factor (A), and free energy of activation (ΔG⁺⁺) for olive oil oxidation were calculated to be ?3.44 × 10^?2°C^?1, 2.21, 98.91 kJ/mol, 12.17 × 10¹² h^?1, and 128.25 kJ/mol, respectively. Each unit change in E_a was accompanied by an average 1.43 × 10¹² change in A, indicating a higher contribution for factor A than for E_a to the olive oil stability. The E_a and A correlated well with the values of enthalpy and entropy, respectively. The values of OSI or IP could be described well by the ΔG⁺⁺ values. Kinetic data indicated that olive oil stability is more affected by the indigenous antioxidants than by the fatty acid composition.     

新时期智能建筑电气施工及管理探究

本文从智能建筑电气施工管理的概述出发，针对新时期智能建筑电气施工及管理中存在的问题，提出了加强智能建筑电气施工及管理的有效措施。     

转型期高职英语应用型人才培养模式研究——以辽宁金融职业学院为例

通过解读英语应用型人才的涵义和特点,分析当下高职英语教学的现状和存在的问题,以我院为例,提出在转型期高职院校培养英语应用型人才的有效意见。     

地质勘查单位转型期科学发展问题探讨

文章通过对地勘单位现状的分析，将地勘单位定位于从快速成长到持续发展之间的转型期，提出了实现地勘单位科学发展的具体举措。     

一种基于北斗信号的星载双站SAR成像频率同步的方法

针对基于北斗信号的星载双站SAR成像频率同步误差,提出一种在高噪声情况下新的频率同步方法。以北斗卫星直达波信号为同步信号源建立同步通道,使用单周期积累的扩频信号优化时频捕获算法得到较精确伪码时延,在码同步后使用已知时延的多周期积累的时频捕获算法获到频率误差。连续10次计算机仿真在SNR=-50db的高噪声环境下频率误差均不超过1.5Hz。