实验性猕猴1型糖尿病模型的建立及评价

7～10岁健康猕猴15只,随机分为Ⅰ、Ⅱ、Ⅲ组,每组5只,分别按照100、125、150mg/kg的剂量一次性静脉注射链脲菌素,连续观察血糖、血浆C肽和胰岛素浓度的动态变化,观察期15周.结果:与注射链脲菌素前比较,注射后1周,Ⅰ组猕猴血糖浓度明显升高,血浆C肽和胰岛素浓度显著下降(P＜0.01),随后趋于正常水平,而Ⅱ、Ⅲ组猕猴血糖浓度明显升高并在随后的时间内持续维持在高水平,血浆C肽和胰岛素浓度持续维持在低水平(P＜0.001),Ⅲ组动物至15周全部死亡.结论:按照125mg/kg的剂量一次性给猕猴静脉注射链脲菌素,可成功复制1型糖尿病动物模型,其维持高血糖和低胰岛素及C肽浓度至少15周.     

河西半荒漠驴驴蒿草原土壤水盐动态及其对牧草生长的影响

对驴驴蒿草原三个草地型(驴驴蒿型,驴驴蒿—红砂型,驴驴蒿+珍珠型)的土壤水盐动态及其与牧草产量的关系进行了研究。结果表明:土壤水分变化受雨量的影响具有阶段性。随着土壤深度的增加,土壤含水量随时间的变化而变小。土壤各层内,春季含水量相近,并呈下降趋势,夏季变化大,秋冬则随土壤深度增加而增加,趋向稳定。盐分随水分而移动,其含量基本上随土壤深度的增加而增加。牧草产量的变化与土壤水分的变化具有“一致性”。在驴驴蒿型和驴驴蒿—红砂型中,驴驴蒿的绝对生长量与0～40cm内各土层的含水量呈显著的正相关,并建立了产量预测模型。     

An animal model for interface tissue formation in cemented hip replacements

OBJECTIVE: To create a model in sheep for investigation of early changes related to the formation of an interface membrane in hip prosthesis. STUDY DESIGN: Experimental study. ANIMALS: Twenty-four female adult Swiss Alpine sheep. METHODS: Sheep were divided into 2 groups of 12 for unilateral cemented total hip arthroplasty. In Group I, the prosthesis was fixed with retrograde cement gun injection to achieve a complete cement mantle, whereas in Group II a primary cement mantle defect was produced. Groups I and II were further divided into 2 sub-groups with study end points of 2 and 8.5 months after surgery. Radiographs were evaluated postoperatively and at euthanasia for migration of the femoral component and bone resorption. Histologic sections were evaluated semiquantitatively for changes in cell types and numbers, and bone reactions; and quantitatively for size of interface membrane and new bone formation. RESULTS: Radiographically, there tended to be an increase in bone resorption and periosteal bone formation throughout the femoral shaft in Group II compared with Group I, but this was only statistically significant at the region of the femoral neck (R5) at both time periods (P<.05). Semiquantitative histologic evaluation revealed significant increases (P<.05) in cellularity, numbers of fibroblasts, giant cells, macrophages, and mononuclear cells, in Group II primarily at 2 months after surgery. This was also true for interface membrane formation and bone remodeling. Quantitative data showed an increased in the size of the interface membrane and area of bone formation at 8.5 months in Group II. CONCLUSIONS: The cement defect model offered controlled and repeatable production of an interface membrane. The results suggest that a primary cement mantle defect could be a possible trigger for implant instability, eliciting a cascade of biomechanical and molecular events in bone tissue leading to aseptic loosening. CLINICAL RELEVANCE: The results show the effect of defects in the cement mantle in promoting interface membrane formation. Long-term and biochemical studies are required to evaluate the relevance of this interface membrane formation.     

庆阳站持久高效草地农业优化模式

根据多年的技术资料和生产实际，采用线性规划法作为系统优化的基本方法，拟定了庆阳黄土高原试验站草地农业结构的优化模式。     

不同生长模型估计籽鹅早期体重发育规律及遗传参数

运用Logistic,Gompertz,VonBertalanfy和Cubic4种非线性生长模型对籽鹅1～1周龄的平均体重进行拟合,并分析生长发育规律及遗传参数。结果表明:虽然4个模型都能描述籽鹅的生长过程,拟合度均超过额0.99;但Logistic模型更符合实际饲养情况,能更好地预测体重,为最佳模型,其相应的体重极限参数A为2267.63g,调节参数B为16.27,瞬时相对生长率C为0.47,生长的拐点时间为6.48周龄,拐点体重为1136.81g。     

未来气候变化条件下青藏高原多年冻土区潜在植被类型面积预估

在青藏高原多年冻土区根据490个植被调查样点数据和3种遥感数据集的27个变量,利用决策树分类模型,模拟出4种代表性浓度路径情景下10个气候系统模式在2050年和2070年的青藏高原高寒草地类型(高寒沼泽草甸、高寒草甸、高寒草原、高寒荒漠和裸地)潜在分布结果。同时为保证数据分析的一致性,利用数据对当前高原草地类型也进行了反演。结果表明:相比当前高寒草地分布面积,预计在2050年和2070年裸地和高寒草甸面积微弱减少,高寒草原和高寒荒漠面积在微弱增加,高寒沼泽草甸面积变化不明显。结果在4种代表性浓度路径情景下的表现基本一致,研究不仅可以为高寒草地气候变化研究提供植被类型相关的数据支持,还可以为青藏高原多年冻土区碳循环的探讨提供部分的方法和理论依据。     

广西巴马小型猪动脉粥样硬化模型的制作

本试验旨在制作广西巴马小型猪动脉粥样硬化模型,初步判断猪发生动脉粥样硬化时的指数值,以期为今后建立相关模型提供依据。试验选取广西巴马小型猪试验组和对照组各10头,通过饲喂高脂高胆固醇饲料建立动脉粥样硬化模型,检测建模过程中血液生化指标,将动脉粥样硬化指数与血管切片作关联分析,初步拟定发生动脉粥样硬化时的指数值。屠宰后血管切片结果显示,试验组有2头广西巴马小型猪发生动脉粥样硬化,对照组均正常。2头广西巴马小型猪的血管切片结果与动脉粥样硬化指数进行关联分析后,初步拟定的动脉粥样硬化指数值在3.8以上,并持续3个月以上。     

Validating a Time Series of Annual Grass Percent Cover in the Sagebrush Ecosystem

We mapped yearly (2000–2016) estimates of annual grass percent cover for much of the sagebrush ecosystem of the western United States using remotely sensed, climate, and geophysical data in regression-tree models. Annual grasses senesce and cure by early summer and then become beds of fine fuel that easily ignite and spread fire through rangeland systems. Our annual maps estimate the extent of these fuels and can serve as a tool to assist land managers and scientists in understanding the ecosystem’s response to weather variations, disturbances, and management. Validating the time series of annual maps is important for determining the usefulness of the data. To validate these maps, we compare Bureau of Land Management Assessment Inventory and Monitoring (AIM) data to mapped estimates and use a leave-one-out spatial assessment technique that is effective for validating maps that cover broad geographical extents. We hypothesize that the time series of annual maps exhibits high spatiotemporal variability because precipitation is highly variable in arid and semiarid environments where sagebrush is native, and invasive annual grasses respond to precipitation. The remotely sensed data that help drive our regression-tree model effectively measures annual grasses’ response to precipitation. The mean absolute error (MAE) rate varied depending on the validation data and technique used for comparison. The AIM plot data and our maps had substantial spatial incongruence, but despite this, the MAE rate for the assessment equaled 12.62%. The leave-one-out accuracy assessment had an MAE of 8.43%. We quantified bias, and bias was more substantial at higher percent cover. These annual maps can help management identify actions that may alleviate the current cycle of invasive grasses because it enables the assessment of the variability of annual grass ? percent cover distribution through space and time, as part of dynamic systems rather than static systems.     

几种仔猪肠道损伤模型的建立及肠道损伤生物标志物的研究进展

肠道不仅是所有营养物质消化吸收的最终场所,也是动物体内最大的免疫器官,是机体防御体系的第一道屏障,维护动物肠道健康对保障养猪生产至关重要。肠道是机体应激反应的中心器官,各种应激因素致使肠道结构损伤与功能紊乱,从而导致仔猪健康不良与生长受阻。因此,建立稳定可靠的肠道损伤模型是研究仔猪肠道损伤机制及营养干预的关键,本文主要介绍了本实验室成功建立的几种仔猪肠道损伤模型,筛选了几种肠道功能紊乱的标志性分子,为猪和人类的肠道功能障碍研究及营养干预提供参考。     

Competition model for international comparisons of livestock

Interbull has been responsible for comparing dairy bulls across countries since the mid‐1980s. The current methodology is called MACE (multiple across country evaluations) which has been in use since 1995. Now that genomic data are being utilized in many countries, this has led to two serious problems. The first is that of preselection of young bulls such that the young animals are no longer a random sample of progeny from a sire by dam mating pair. Secondly, some countries are becoming less willing to share genomic data with Interbull. Both issues raise concern over the future of Interbull and international comparisons. This paper suggests a competition model as a potential replacement for MACE. The competition model makes pairwise comparisons between all pairs of bulls within a country and combines these differences across countries through bulls that are used in more than one country. Pedigree information is ignored as are all genomic data because bulls are treated as fixed. The model produces one international ranking of bulls averaging out any genotype by environment interactions which may exist. The competition model is illustrated by a small example. The limitations and advantages of the competition model are discussed.