Intramammary expression and therapeutic effect of a human lysozyme-expressing vector for treating bovine mastitis

To develop a gene therapy strategy for treating bovine mastitis, a new mammary-specific vector containing human lysozyme (hLYZ) cDNA and kanamycin resistance gene was constructed for intramammary expression and clinical studies. After one time acupuncture or intracisternal infusion of healthy cows with 400 μg of the p215C3LYZ vector, over 2.0 μg/ml of rhLYZ could be detected by enzymatic assay for about 3 weeks in the milk samples. Western blotting showed that rhLYZ secreted into milk samples from the vector-injected cows had molecular weight similar to that of the natural hLYZ in human colostrums. Twenty days after the primary injection, the quarters were re-injected with the same vector by quarter acupuncture and even higher concentrations of rhLYZ could be detected. Indirect competitive ELISA of milk samples showed that the vector injection did not induce detectable humoral immune response against hLYZ. Clinical studies showed that twice acupuncture of quarters with the p215C3LYZ vector had overt therapeutic effect on clinical and subclinical mastitis previously treated with antibiotics, including disappearance of clinical symptoms and relatively high microbiological cure rates. These data provide a solid rationale for using the vector to develop gene therapy for treating bovine mastitis.     

美国五次并购浪潮及其历史背景

美国历史上曾发生过五次大的并购浪潮，对这段历史进行研究，对于进一步加强对我国并购活动管理工作具有重要的指导意义。     

浅谈数字逻辑实验教学改革

结合实验教学实际 ,对传统数字逻辑实验教学体系进行了改革 ,提出了在新形势下确立数字逻辑实验教学目标、内容、组织形式、手段和评价的措施 .     

水下沉桩施工新技术

肇庆换流站供水工程之一的五尺峡取水泵站施工中，在受施工条件限制的情况下，采用将钢筋混凝土预制桩改为开口钢管桩，将双排桩改为单排桩，尝试搭设水上竹平台作沉桩施工平台等措施均取得成功，保证了质量、安全、进度，降低了施工成本．     

食物安全的内涵及其与相关概念的比较

食物是人类赖以生存和发展的基本物质基础,食物安全状况不仅关系到人民的身体健康,更影响到国家的安全和民族的整体素质.因此,食物安全成为政府重视、社会关注和人民群众极大关心的焦点,也必然地成为科学研究的重点课题.     

乙酸乙酯分离竹子中木质素制浆造纸研究

用乙酸乙酯浸提竹子制取纸浆，并用造纸行业相关国家标准对纸浆进行了分析。探讨了乙酸乙酯浓度、反应温度、反应时间、原料与溶剂的固液比对纸浆质量的影响。实验结果表明：当乙酸乙酯浓度为60％、反应温度为180℃、反应时间2h、原料-溶剂比为1：6时，制得的纸浆中残余木素含量相对较低、纸浆得率较高。     

断裂带中岩石硅化的微束研究

断裂带中岩石的硅化现象,通常称之为硅化岩或硅化破碎带,即经动力变质作用的断层岩,通过微束技术对其观察,它们显示出下列特征:在扫描电镜(SEM)下,硅化物质表现为细脉状,而在偏光里微镜下则表现为浸染状;对硅化岩进行组构观察,可见压扁 S 面和剪切 S 面;在透射电镜(TEM)下,可进一步区别不同的位错现象;断裂带岩石的硅化现象是受组成岩石的化学元素的构造地球化学作用所制约的,包括动力分异和化学亲和作用,动热变质作用和退化变质作用,氧化和还原作用以及脱水和水解作用。     

双间隙加速管设计中几个问题的研究

对加速管的放电或击穿与绝缘环，电极材料，极间距离和真空度等因素的关系进行了分析，为加速管的设计提供了依据。以此研制的加速算运行正常。     

A High Speed Detection Scheme for Point Targets in a Multitarget Environment

The purpose of this paper is to develop a high speed detection scheme for moving and / or stationary point targets in a multitarget environment as registered in an IR image sequence. An iterative approximate 3-D line searching algorithm based upon the geometric representation of lines (for non-maneuvering targets in space) in a 3-D space is derived. The convergency of the algorithm is proved. An analysis is performed of the theoretical detection performance of the algorithm. The statistical experiment results show high effectiveness and computational efficiency of the algorithm in the case of low SNR. The idea may be employed to satisfy the real-time processing requirement of an IR system.     

Fe_3Al的抗高温氧化和耐热腐蚀性能

在７００℃与８５０℃的高温下，Ｆｅ＿３Ａｌ金属间化合物表面形成了Ａｌ＿２Ｏ＿３保护膜，使其抗氧化性能远优于不妨钢，２％Ｃｒ（原子百分比）加入Ｆｅ＿３Ａｌ会导致氧化过程初期氧化速率的增高，在熔融的硫酸盐和高压锅炉的烟气中，Ｆｅ＿３Ａｌ的耐热腐蚀性能优于高温合金ＧＨ１３２．