杯形砂轮精密磨削WC-Co涂层的磨削力

使用杯形砂轮进行磨削,可以获得较高的加工效率和表面质量.但由于杯形砂轮的平面磨削方式与普通外圆砂轮平面磨削存在差异,故传统的磨削力建模不适合杯形砂轮的平面磨削.为了从本质上解释杯形砂轮磨削力的各种现象,本文对杯形砂轮的磨粒切削过程进行了分析,提出了杯形砂轮有效磨削宽度的概念,分析了杯形砂轮磨削陶瓷涂层时的磨削力,建立了杯形砂轮精密磨削陶瓷涂层磨削力的理论公式.磨削力工艺试验结果验证了理论公式的有效性和正确性.     

Control of stress-dependent cardiac growth and gene expression by a microRNA

The heart responds to diverse forms of stress by hypertrophic growth accompanied by fibrosis and eventual diminution of contractility, which results from down-regulation of alpha-myosin heavy chain (alphaMHC) and up-regulation of betaMHC, the primary contractile proteins of the heart. We found that a cardiac-specific microRNA (miR-208) encoded by an intron of the alphaMHC gene is required for cardiomyocyte hypertrophy, fibrosis, and expression of betaMHC in response to stress and hypothyroidism. Thus, the alphaMHC gene, in addition to encoding a major cardiac contractile protein, regulates cardiac growth and gene expression in response to stress and hormonal signaling through miR-208.     

牛体内卵形巴贝斯虫裂殖体阶段的形态观察

 将“洁净”长角血蜱成虫饲喂在人工感染卵形巴贝斯虫的牛体上，俟饱血脱落并产卵孵化后，利用其次代幼虫、若虫和成虫、分别叮咬感染健康易感牛，对牛体内裂殖体阶段的卵形巴贝斯虫形态进行了观察。结果，在幼虫、若虫和成虫感染牛的末梢血液、心、肝、脾、肺、肾、淋巴结切面刮取物和体表淋巴结穿刺物涂片的淋巴细胞中，均观察到了裂殖体。所见裂殖体有两种类型；即由小梨子形裂殖子组成的小裂殖体和由大梨子形裂殖子组成的大裂殖体。     

鲤鱼年龄的硬组织鉴定研究

鲤鱼背鳍棘，背鳍第１支鳍骨的年轮特征与耳石，脊椎骨，鳞片均很明显，鳃盖骨和胸鳍棘不适用于年龄鉴定，并提出这些年龄鉴定材料中年带形成的观点。     

奶牛催乳素基因多态性与产奶性状的关系

通过PCR-RFLP的方法,分析催乳素基因exon3在543头北京荷斯坦母牛中的多态性,得到3种基因型:AA、AB和BB,基因型频率分别为0.734,0.257,0.009,并对不同基因型间产奶性能进行了最小二乘法拟合线性模型分析。结果表明:在泌乳Ⅰ期,AA和AB基因型奶牛的奶、乳脂和乳蛋白产量高于BB基因型(P<0.01),在泌乳Ⅱ期,AB基因型奶牛的的奶、乳脂和乳蛋白产量高于AA基因型(P<0.01);在泌乳Ⅱ和Ⅲ期,AA基因型奶牛的乳蛋白率高于AB基因型(P<0.05)。     

Cyclosporine A inhibits intima proliferation of rat abdominal aortas injured by balloon

AIM: To observe the effect of cyclosporine A on intima hyperplasia of rat abdominal aortas injured by balloon.METHODS: Thirty-six healthy adult male SD rats were randomly divided into 3 groups: sham group (n=12), balloon-injured group (n=12) and cyclosporine A treatment group (n=12).From the 3rd day before injury to the 30th day after injury, the rats in cyclosporine A treatment group were treated with cyclosporine A at a dose of 12.5 mg/kg everyday, while the rats in sham group and balloon-injured group were fed with the same volume of water.On the 30th day after injury, the specimens were obtained from the rats.HE staining and immunohistochemistry were used to measure the expression level of calcineurin (CaN) in arterial wall.Pathological changes of the arterial wall were observed under light microscope.The expression of CaN and nuclear factor 3 of activated T-cells(NFATc3) in the abdominal aortas was detected by the technique of real-time PCR.RESULTS: Intimal hyperplasia was observed in balloon-injured rats.The neointima was not uniform in thickness on the 30th day.The thickness of the intimal layers and the ratio of the intimal to the medial layers in cyclosporine A group were obviously lower than those in balloon group(P<0.05).Immunohistochemistry revealed that calcineurin expression increased after balloon injury, but the expression of calcineurin in cyclosporine A group was obviously decreased as compared with balloon group (P<0.05).The results of real-time PCR showed that the mRNA expression of calcineurin and NFATc3 in cyclosporine A group was significantly lower than that in balloon-injured group (P<0.05).CONCLUSION: Cyclosporine A attenuates restenosis by suppressing the CaN-NFATc signaling pathway.     

Paraquat detoxification with p-sulfonatocalix-[4]arene by a pharmacokinetic study

The p-sulfonatocalix[n]arenes are supposed to show potential application in the clinical treatment of viologen poisoning. In the present study, p-sulfonatocalix[4]arene (C4AS), the most common derivative of p-sulfonatocalix[n]arenes, is used to study the antidotic mechanism for paraquat (PQ) by pharmacokinetics in vivo. A high-performance liquid chromatography (HPLC) method was established to determine the concentration of PQ in rat plasma. The results showed that the peak plasma concentration (C(max)) and area under the plasma concentration-time curve (AUC(0-t)) were significantly lower after C4AS intervention than in the PQ intoxication group. It was considered that C4AS has great effective detoxication to PQ poisoning, and the results of in vitro intestinal absorption studies showed that C4AS can inhibit the absorption of PQ via oral administration by forming a stable inclusion constant.     

夹持式棉花精密穴播轮改进设计与试验

针对夹持式棉花精密穴播轮作业引起的振动脱种问题,改进了取种器的结构,增设了护种装置。应用二次回归通用旋转组合试验方法,建立了穴播轮排种性能指标与取种器夹种口主要尺寸间的回归方程。分析了试验因素对穴播轮排种性能指标的影响规律,对于新陆早-26号棉种在单粒率最大、重播率和空穴率在一定范围内的条件下,优化得出夹种板长度为4.50mm、夹种口宽度为5.70mm、夹种口开度为7.50mm。试验表明,改进后的穴播轮减小了振动对精密取种的影响。     

半导体生物培养箱的研制

研制了一种利用半导体作为温控元件的生物培养箱.利用半导体体积小、传热速度快以及无噪声等优点,尝试将其作为生物培养箱的温控元件,并利用ARM开发板进行核心程序的设计,且使用液晶触摸屏进行温、湿度的实时监测,使得设计出的培养箱具有人机界面友好、操作简单等优点,并通过实验验证其具有良好的控制效果.     

组培枣苗基因组DNA提取方法及其含量的比较

本文以组培二倍体木枣、四倍体变异苗和二倍体京枣苗为供试材料,采用琼脂糖凝胶电泳和紫外分光光度检测技术,研究了不同提取方法对其叶片基因组DNA的提取效果。结果表明,CTAB法提取枣叶片DNA的效果优于SDS法,表现为蛋白质杂质干扰少,DNA结构完整、纯度与得率高;用不同方法提取的样液中DNA片段的大小和分布是不同的,以改进的CTAB法提取的样液中大片段的DNA分子较多,所以在其底部分布较多,而用SDS法提取的样液中小片段的DNA分子较多,故在其上部分布较多;电泳时不同的加样量获得的DNA带也有较大差异,试验选出CTAB法提取样液的适宜的加样量为5μL（7.485μg）,SDS法提取样液的适宜的加样量为4μL（5.988μg）;枣品种间DNA的含量明显不同,木枣四倍体的DNA含量（3.074μg/μL）相当于组培木枣二倍体（1.497μg/μL）的2倍,也明显地高于京枣二倍体（2.182μg/μL）。这些结果为枣树遗传种质资源的研究奠定了一定的科学与技术基础。