Intramammary infusion of an Enterococcus faecium SF68 preparation promoted the involution of drying off Holstein cows partly related to neutrophil‐associated matrix metalloproteinase 9

A problem for dairy cows following milk stasis is to cope with a high risk of intramammary infection and there is a need to initiate an extensive renewal of secretory modules in mammary glands so that milk production in next lactation may be optimized. We recently reported that ultrasonicated Enterococcus faecium SF68 (SF68) is compatible with cow mammary glands and an enhancer of innate immunity during the immediate post‐milk stasis period. The current study further examines the concomitant effect of ultrasonicated SF68 on mammary tissue remodeling. Four Holstein cows each received intramammary infusions of regular antibiotic dry‐cow formula (positive control) and two different doses of SF68 in different quarters. Analyses of individual quarter secretion samples showed faster neutrophil infiltration, earlier modifications in protein composition, including caseins and lactoferrins, as well as more prompt elevation of the specific unit of 92‐kDa matrix metalloproteinase 9 (MMP9) in SF68‐infused quarters compared to the positive controls. Intramammary infusion of ultrasonicated SF68 seems able to accelerate the regression of mammary synthetic capacity and potentiate the breakdown of glandular extracellular matrix, indicating a more efficient mammary gland involution. Correlation analyses imply that the ability of ultrasonicated SF68 to induce faster neutrophil chemotaxis and the associated MMP9 release is partly responsible.     

高产优质水稻品种“滇黎202”的选育初报

 利用高杆大穗的蛋白种(BP)(粘米)与西双版纳地方种毫干和株型紧凑,抗性强的国际稻IR26杂交的中间材料杂交,选育出高产,优质抗病的品种──"滇黎202"。     

乌龙茶品种的机采适应性

多元回归及通径分析结果表明,衡量乌龙茶品种机械化采摘(简称机采)产量的因子为新梢生长量(通径系数P_y=1.2764)、发芽密度(P_y=0.9546)、新梢粗度(P_y=0.5998)和着叶数(P_y=-0.6087),其中前二者对产量的主效应和互作效应最大。机采产量与各因子之间的关系式为=-292.51+1.90x_1+29.78x_2-59.51x_3+1359.45x_4。质量因子为发芽整齐度。据此建立乌龙茶品种机采适应性评价模型,对梅占、黄旦、毛蟹3个乌龙茶品种的机采适应性作出评判。评判结果表明,梅占最适合机采,其次是毛蟹,第三为黄旦。这与实际情况相符。生产上及育种中可利用此模型选择或选育适合机采的乌龙茶品种。     

黄牛过食精料病理学与治疗同步研究

本试验将受试牛分别过食玉米和大豆进行病理学与治疗同步研究。结果表明两组牛瘤胃液和血液ｐＨ值发病前后有明显差异（Ｐ＜０．０５和Ｐ＜０．０１）;两组过食后的变化指标都是酸中毒的典型指征而非碱中毒。鲎试验检测胃液和血液细菌内毒素含量为１．２～４．８ｎｇ／ｍｌ,证实酸中毒中的同时两组都并存革兰氏阴性细菌内毒素血症。在与病理学变化同步治疗时,采取抗酸中毒、抗内毒素血症及解除脱水为主的综合治疗,对危笃病例取得了满意疗效     

基于PID参数模糊自适应的汽车EPS助力特性研究

在分析电动助力转向（EPS）系统结构及动力学特性基础上,构建了系统动力学模型和仿真模型.根据助力电机目标电流决策设计了助力特性曲线,同时采用自适应模糊PID控制策略对电动机目标电流进行闭环跟踪控制.通过对比仿真结果中目标电流响应速度、跟踪性等转向参数表明：该控制策略能够提高电动转向控制系统响应性、跟踪性能,使得汽车具有更好的转向性和操作稳定性.     

大豆品种磷素积累和利用效率的基因型差异

在酸性红壤的立培条件下，16个南方春大豆品种磷积累量存在极显著差异。不施磷处理，品种间磷积累量最高的比最低的增加48．3％；施磷处理则增加33．9％。施磷后品种间磷积累量增加15．75～21．97mg／株，磷肥利用率为10．9％～15．6％。大豆磷积累量与品种生育期相关性不显著，但不施磷条件下与苗期叶片酸性磷酸酶活性是显著正相关。不施磷时，品种间籽粒产量磷利用效率相差143．73mg／mgP，生物学产量磷利用效率相差406.78mg／mgP；施磷时，分别相差64．51mg／mgP和110．95mg／mgP。     

Proteomic analysis of the hypothalamus of broiler‐type Taiwan country chickens in response to acute heat stress

The hypothalamus is a critical center for regulating heat retention or dissipation. This study investigated global protein changes in the hypothalamus of broiler‐type Taiwan country chickens (TCCs) after acute heat stress. Twelve TCC hens aged 30 weeks were allocated to groups subjected to acute heat stress at 38°C for 2 hr without recovery, with 2 hr of recovery, and with 6 hr of recovery; a control group was maintained at 25°C. Hypothalami were collected for protein expression analysis at the end of each time point. The results showed 114 protein spots differentially expressed after acute heat stress. Most of the differentially expressed proteins were involved in cellular processes, metabolism, transport, and cellular component organization. Functional annotation analysis suggested that these proteins were related to cellular defensive responses against heat and oxidative stress, detoxification and toxin export/delivery, cytoskeleton integrity, oxygen transport, and neural development. The results of this study suggest that acute heat stress damages the hypothalamus of broiler‐type TCCs through oxidative stress and provokes a series of responses to stabilize protein structures, degrade misfolded proteins, and remodel cytoskeletons for attenuating the detrimental effects by acute heat stress.     

Trace elements and polycyclic aromatic hydrocarbons in road gully sediments from different land uses,Hong Kong

Purpose

This study investigated the concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), and polycyclic aromatic hydrocarbons (PAHs) in sediments collected from gully pots for road drainage in Hong Kong. The presence and intensity of anthropogenic contamination of road gully sediments were assessed. Identifications of potential sources of trace elements and PAHs were performed to help understand the situation for future control of pollution to the land and aquatic environments.

Materials and methods

Gully sediment samples were collected from gully pots of 18 roads that are potentially exposed to different pollution sources in Hong Kong. The selection of roads considered different road features, adjacent land uses, and traffic volumes. Composite samples were collected for the analysis of trace elements (Cd, Cr, Cu, Pb, Ni, and Zn) and PAHs by an accredited environmental testing laboratory. Geo-accumulation index (I_geo), contamination factor (C_f), modified degree of contamination (mC_d), ecological risk factor (Er), and pollution load index (PLI) were used to assess the level of ecological risk of trace element contamination. Positive matrix factorization (PMF) and PAH diagnostic ratios were applied to identify the sources of trace elements and PAHs.

Results and discussion

Elevated trace element concentrations were commonly found in gully sediments. The concentrations of Zn (267–3700 mg kg^?1) were the highest compared to the other trace elements. Noticeable high concentrations of Cu (27–1020 mg kg^?1), Pb (21–332 mg kg^?1), and Cr (14–439 mg kg^?1) were found in all samples. The PAH contents were moderate to high (0.6 to 24.7 mg kg^?1). Commercial/industrial emissions and road features that cause frequent acceleration-deceleration and turning events showed important influences on the contaminant levels. Strong correlations between the concentrations of Cd, Cr, Pb, and Zn were identified, implying that these trace elements are likely from common sources. The contamination assessment indices reflect significant sediment pollution. The ecological risk ranges from the considerable/moderate-risk class to over the high-risk class.

Conclusions

The collected gully sediments are identified as highly contaminated and need to be isolated from the environment upon final disposal. Through the comprehensive analysis of the collected data, this study provides a detailed insight into the contaminant levels of road gully sediments and potential sources of contamination. Disposal of gully sediments and potential impacts due to release of contaminants into the downstream aquatic environment during rainstorm events should receive attention and need further investigation.

     

影响笋用小竹造林成活率因子分析

针对嵊州市目前部分笋用小竹造林单位成活率较差的状况,对1986年以来营造的笋用小竹在确保造林质量的前提下开展了调查,调查面积1000余亩,母竹总株数为47897株。通过对造林季节、土壤种类、母竹年龄、水分管理、母竹质量等因子对笋用小竹造林成活率影响的分析,阐明影响笋用小竹造林成活率的主要因子,提出提高造林成活率的措施。