轴向柱塞液压马达机械液压耦合仿真分析

为了使轴向柱塞液压马达仿真模型接近于物理样机,采用机械、液压耦合模型并综合考虑柱塞和缸体、柱塞和斜盘等摩擦副的摩擦力和液体的粘性阻尼以及减小压力脉动的三角阻尼槽等因素,建立了轴向柱塞液压马达仿真模型。液压马达高压油推动柱塞位移、机械能推动柱塞排油,实现液压能和机械能相互转换,主要包括压力源(恒流源或恒压源)、负载(外部阻力矩,转动惯量)、柱塞缸体组件、柱塞往复和旋转运动转换组件、配流窗口等。仿真结果与有关文献中液压马达实验数据进行对比,马达转速、加速时间、最大输出流量的仿真值与实验值误差均小于5%,验证了仿真模型能够保证较好的计算精度。仿真结果表明,由于卸荷槽和腰型槽过渡区域有通流面积突变现象,容易产生局部压力脉冲现象,且转速越高压力波动越大,通过优化卸荷槽结构型式和参数可以减小脉动冲击;液压马达工作特性受负载的影响,负载的总转动惯量大时加速时间长而稳定转速波动区间窄,相应产生的脉动也趋于减小。     

Quantification of tryptase and T-cell immunoglobulin mucin 1 double-positive mast cells in different degrees of human periodontitis

AIM：To examine the expression of T-cell immunoglobulin mucin 1 (TIM-1) on tryptase-positive mast cells (MCs) in different severities of human chronic periodontitis. METHODS：Human gingival specimens (n=92) were involved in this study, including healthy control (n=27), mild chronic periodontitis (n=34) and severe chronic periodontitis (n=31). The gingival specimens were fixed in 4% formaldehyde. Paraffin embedding and serial sectioning with hematoxylin and eosin staining were performed for histopathological examination, and double-immunofluorescence staining was conducted for identification of tryptase-TIM-1 double-positive MCs in the gingival tissues. RESULTS：Compared with the healthy controls, the densities (cells/mm2) of tryptase-TIM-1 double-positive MCs were significantly increased in both mild chronic periodontitis group (P<0.05) and severe chronic periodontitis group (P<0.01). However, compared with mild chronic periodontitis group, both the score of gingival tissue inflammation and the density of tryptase-TIM-1 double-positive MCs in the gingival tissues were significantly increased in severe periodontitis group (P<0.05). CONCLUSION：Significantly increased number of tryptase-TIM-1 double-positive MCs has the similar tendency as the severity of periodontitis inflammation in human chronic periodontitis, suggesting that tryptase-TIM-1 double-positive MCs may play an important role in human chronic periodotitis.     

Effect of small interfering RNA on expression of β2M in pre-differentiated bone marrow mesenchymal stem cells

AIM：To study the effect of small interfering RNA (siRNA) on the expression of beta 2-microglo-bulin (β2M) in pre-differentiated bone marrow mesenchymal stem cells (BMSCs). METHODS：The β2M siRNA was transfected into the pre-differentiated BMSCs with Lipofectamine 2000. BMSCs were divided into transfection group, blank control group and negative control group. The expression of β2M at mRNA and protein levels was determined by real-time qPCR, Western blotting and laser confocal microscopy. The productions of aggrecan and type II collagen in pre-differentiated BMSCs were determined by toluidine blue staining and type Ⅱ collagen immunofluorescence. RESULTS：The results of real-time qPCR, Western blotting and laser confocal microscopy showed that siRNA successfully inhibited the expression of β2M at mRNA and protein levels in the pre-differentiated BMSCs. The results of toluidine blue and type Ⅱ collagen immunofluorescence staining showed that siRNA does not affect the productions of aggrecan and type Ⅱ collagen in the pre-differentiated BMSCs. CONCLUSION：siRNA targeting β2M reduces the expression of β2M in the pre-differentiated BMSCs and does not affect the chondrocyte characteristics of pre-differentiated BMSCs.     

秋海棠新品种———‘昆明鸟’、‘康儿’和‘白雪’

 ‘昆明鸟’秋海棠系由大王秋海棠和掌叶秋海棠杂交F₁ 选育而成, 常有多节短茎, 叶浅裂、被浅白斑, 直立性较强, 抗倒伏, 抗白粉病, 具较高的观赏价值。‘康儿’秋海棠由大王秋海棠和长翅秋海棠杂交F₁ 选育而成, 常有1～3 节花茎, 叶大型、浅裂, 长势旺盛, 抗白粉病极强, 适宜栽培观赏。‘白雪’秋海棠为野外发现的自然杂交新品种, 通过研究证实其为变色秋海棠和掌叶秋海棠的杂交F₁ 代个体, 为根茎类秋海棠, 无地上茎或地上茎不明显, 叶片中型、被毛、浅裂且密被白色斑点, 十分美丽, 对白粉病有较强的抗性。     

20份欧洲型黄瓜种质资源的半致死温度与耐热性研究

为探讨不同欧洲型黄瓜种质资源对高温的适应性差异,为耐热种质资源筛选及耐热机理的深入研究提供理论和实践依据,以20份欧洲型黄瓜的叶片为材料,设置6个高温处理,以室温为对照,测定浸提液电导率值并计算相对电导率,通过拟合Logistic方程,计算半致死温度(LT50)。试验结果表明,随着温度升高,相对电导率呈"S"型曲线,且相对电导率与处理温度存在显著的直线相关关系,通过计算"S"型曲线拐点求得20份欧洲型黄瓜的半致死温度在45~51℃,其中33-2的半致死温度最高,达到50.09℃,37-1的半致死温度最低,为45.82℃。20份欧洲型黄瓜的耐高温能力由强到弱依次为33-275-232-233-111-231-209-236-276-136-137-210-135-276-211-143-235-175-132-137-1。因此,半致死温度可作为评价欧洲型黄瓜耐热性的一个可靠指标。     

Does Dietary Administration of Lactococcus lactis Modulate the Gut Microbiota of Grouper,Epinephelus coioides

The effect of dietary administration of probiotic Lactococcus lactis MM1 for 60 d on the autochthonous microbiota in the foregut, midgut and hindgut of juvenile grouper, Epinephelus coioides, was evaluated using polymerase chain reaction‐denaturing gradient gel electrophoresis (DGGE). Samples collected from the probiotic and control groups showed different DGGE patterns, while 11 common bands presented in both groups. The similarity dendrogram revealed three different clusters depending on the three sections of the gastrointestinal (GI) tract, and the probiotic triplicates in each GI section were generally clustered into one group distinctly different from the corresponding control triplicates. Increased species richness and Shannon index were observed in the foregut, midgut, and hindgut samples in the probiotic group compared with the control group, which suggested that probiotic L. lactis MM1 could improve the autochthonous microbial diversity along the GI tract of E. coioides. The growth of many potentially beneficial and unidentified bacteria was stimulated by the probiotic, whereas the growth of some potential harmful species, like Staphylococcus saprophyticus, was depressed.     

技术推广部门在农业产业发展中的作用分析——以桂林市食用菌产业为例

本文以桂林市食用菌产业为例,选取市、县、乡三级政府部门领导、管理人员以及食用菌种植区域内不同面积、不同产量的种植户为调查对象,采取座谈、访问、调查问卷等方式,分析技术推广部门在农业产业发展中的作用及制约技术推广部门发挥作用的因素进行分析,并对如何发挥技术推广部门在发展食用菌产业中的作用提出对策建议.     

TDP穴区照射调整奶牛分娩前后血液流变性的研究

 健康妊娠奶牛20头随机分为照射组和对照组各10头。照射组奶牛分别于分娩前10～3d和产后1～3d,用TDP辐射仪交替照射百会和后海穴区,每天1次,60min。奶牛分别于分娩前20、15、10、5、3、1d,1～4h和产后1～4h、1、3、15d,颈静脉采血样。检测血样的ηb80s-1,ηb20s-1,ηp,PCV,ηr,RI,AI和血浆的Glu,TP,FG的含量。与对照组比较,结果:TDP穴区照射对奶牛分娩前和后一定时期内的ηb80s-1,ηb20s-1和ηp具有一定调整作用;调整和改善分娩过程中的血糖含量和血液的流动性与变形性,减少血液丢失等,从而提高机体分娩应激反应综合适应能力。其作用机理可能是TDP辐射红外热能的经、穴感应调整作用和机体产生的生物能量效应等的综合。     

家畜性别鉴定与性别控制技术在猪育种中的应用

简介了胚胎性别的鉴定和采用X精子与Y精子分离的性别控制技术在猪育种中的应用。     

肉仔鸡强毒新城疫的诊断与治疗

近年来,河南省肉仔鸡发生新城疫的病例逐渐增多,其临床症状和剖检病变与低血糖综合征、药物中毒等极为相似,容易发生误诊,延误治疗时机。为此,笔者将近年肉仔鸡新城疫的发病特点和治疗方法进行了总结。