基于合成法的定位误差的分析与计算

为保证机床夹具设计的可靠性,定位误差的计算是机床夹具设计过程中必不可少的重要环节之一。为此从定位误差的产生机理出发,介绍了定位误差的概念、产生原因,并给出计算公式,有助于快速实现定位误差的求解。     

Effects of Lactic Acid Bacteria and Fructooligosaccharides on Growth Performance,Nutrient Digestibility and Serum Biochemical Indices of Arctic Foxes (Alopex lagopus) during Early Growth Period北大核心CSCD

This experiment was conducted to study the effects of dietary lactic acid bacteria (LAB) and fructooligosaccharides (FOS) on growth performance, nutrient digestibility and serum biochemical indices of Arctic foxes (Alopex lagopus) during early growth period. Sixty male post-litter Arctic foxes with the average body weight of (1.16±0.15) kg and at the age of (45±3) days were randomly assigned to 4 groups with 3 replicates per group and 5 foxes per replicate. The foxes were fed the following diets, respectively: basal diet (control group), basal diet+3×109 CFU / kg LAB (LAB group), basal diet+5 g / kg FOS (FOS group) and basal diet+3×109 CFU / kg LAB+5 g / kg FOS (LAB+FOS group). The experiment lasted for 30 days. The results showed as follows: 1) on the days 1 to 15, the diarrhea rate of foxes in the LAB group and LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05). On the days 16 to 30, the average daily gain of foxes in the LAB+FOS group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); the diarrhea rate of foxes in the LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); compared with the FOS group, the feed to gain ratio of foxes in the LAB+FOS group was significantly decreased (P<0.05). 2) The dry matter digestibility of foxes in the LAB + FOS group was significantly higher than that in the control group and FOS group (P < 0.05), but had no significant difference with LAB group (P>0.05). There were no significant differences in nitrogen intake, fecal nitrogen, urine nitrogen, nitrogen deposition, net protein utilization and protein biological value among all groups (P>0.05). 3) Serum total protein (TP) content of foxes in the LAB+FOS group was significantly higher than that in the FOS group (P<0.05), but had no significant difference with control group and LAB group (P>0.05). Serum albumin (ALB) content of foxes in the LAB group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB+ FOS group (P>0.05). Serum urea nitrogen (UN) content of foxes in the LAB+FOS group was significantly decreased compared with the control group (P < 0. 05). In conclusion, the combined supplementation of 3 × 109 CFU / kg LAB and 5 g / kg FOS in the diet is beneficial to reduce diarrhea rate, improve dry matter digestibility, improve body immune level, and promote the growth of Arctic foxes during early growth period. © 2023 Chinese Journal of Urology. All rights reserved.     

我国水产品品牌战略实施现状及对策研究

水产品品牌战略是提高产品质量管理水平,促进水产品行业良性发展的有效途径,然而由于多种原因,我国水产品品牌建设一直进展较为迟缓.该研究对我国水产品品牌战略的实施状况进行研究,分析水产品品牌战略实施过程中存在的问题与障碍,在此基础上提出我国实施水产品品牌战略的方法与途径.     

水泵机组状态监测与故障诊断系统研究

从20世纪60年代到21世纪，我国的泵站工程为输水、供水以及防洪减灾提供了有力保障。针对水泵机组的状态监测与故障诊断进行研究，建立水泵机组状态监测与诊断的软件及各分析模块与数据库，进行机组性能的预测研究，为水泵机组的状态维修提供支持。     

以“德”抗“位”的回归——论孟子、赵岐和朱熹的君臣观

在君臣关系上，先秦孟子主张德高于位，东汉赵岐虽未能继承孟子衣钵以德抗位，却也守道不违，守住了人臣的基本原则。而至南宋朱熹在吸纳与反省宋代《孟子》议题的时候，再次开掘和彰显仁义道德本真，以德抗位的人臣之本也自东汉赵岐之后得以回归。     

鱼胶风味挂面加工工艺的研究

研究了以鱼鳞、鱼皮及鱼鳍为原料进行预处理,提取其营养成分,然后添加到挂面中,做成一款独特的鱼胶风味挂面的加工工艺。同时对鱼胶的提取、除腥及调味进行了较深的探讨,结果显示,鱼胶挂面的光滑度及弹韧性均比一般产品更好,其口感及理化指标均达花色挂面国家标准。     

AR regulates porcine immature Sertoli cell growth via binding to RNF4 and miR-124a

Sertoli cells are the only somatic cells in the seminiferous epithelium which directly contact with germ cells. Sertoli cells exhibit polarized alignment at the basal membrane of seminiferous tubules to maintain the microenvironment for growth and development of germ cells, and therefore play a crucial role in spermatogenesis. Androgens exert their action through androgen receptor (AR) and AR signalling in the testis is essential for maintenance of spermatogonial numbers, blood–testis barrier integrity, completion of meiosis, adhesion of spermatids and spermiation. In the present study, we demonstrated that AR gene could promote the proliferation of immature porcine Sertoli cells (ST cells) and the cell cycle procession, and accelerate the transition from G1 phase into S phase in ST cells. Meanwhile, miR-124a could affect the proliferation and cell cycle procession of ST cells by targeting 3′-UTR of AR gene. Furthermore, AR bound to the RNF4 via AR DNA-binding domain (DBD) and we verified that RNF4 was necessary for AR to regulate the growth of ST cells. Above all, this study suggests that AR regulates ST cell growth via binding to RNF4 and miR-124a, which may help us to further understand the function of AR in spermatogenesis.     

猪场生物安全体系中十个通道的设计应用

2018年8月开始,非洲猪瘟在我国快速多点发生,该病是高度接触性传染性疾病,目前无有效的疫苗和药物控制,各大公司和养殖户开始了猪场生物安全体系的升级改造。两年后我国大部分猪场的成功复产,全国生猪出栏量的大幅提升,证明了生物安全措施巨大效力;同时在严格的生物安全措施下创新了精准剔除、快速复产等操作,进一步证明了生物安全措施的有效作用。文章主要介绍猪场生物安全体系中入口(大门)和出口(后门)最为关键防线处的通道设计,方便所有的生物安全操作能够高效落实,切断病原轻易进出猪场的途径。