PET／PC共混物的辐射效应研究

研究了经溶液共混制备的聚对苯二甲酸乙二醇酯／聚碳酸酯（ＰＥＴ／ＰＣ）共混物的辐射效应。结果表明：ＰＥＴ／ＰＣ共混物在辐照过程中未发生酯交换反应和交联反应，但有降解反应发生。在研究的剂量范围内，辐照对ＰＥＴ／ＰＣ共混物中ＰＥＴ和ＰＣ的晶体形态影响不明显。     

以YAG为添加剂的气压烧结氮化硅

本文以添加ＹＡＧ的反应烧结氮化硅（ＲＢＳＮ）为前驱体，采用气氛加压烧结的工艺，在０．５～９．０ＭＰａ氮气压力范围，研究了不同氮压对烧结体的密度、相组成、强度和显微结构的影响及其相互间的关系。研究表明，通过改变氮气压力能有效地调控材料的显微结构，材料的性能又受控于显微结构的变化。     

Expression of bovine beta-lactoglobulin/human erythropoietin fusion protein in the milk of transgenic mice and rabbits

We have generated several transgenic mouse lines and rabbits expressing efficiently (up to 0.3 mg/ml in mice and up to 0.5 mg/ml in rabbits) human erythropoietin in their milk as bovine beta-lactoglobulin fusion protein. Human erythropoietin cDNA was inserted in frame into exon 5 of the bovine beta-lactoglobulin gene with a linker oligonucleotide encoding the cleavage site for bacterial IgA protease. RNA analysis performed on one lactating transgenic mouse and one transgenic rabbit revealed that the fusion gene was expressed almost exlusively in the mammary gland, although low amounts of transgene-derived RNA were detectable in salivary glands and uterus or in the kidney. The fusion protein was specifically cleaved with IgA protease. The erythropoietin part obtained upon digestion had a lower molecular mass than recombinant erythropoietin produced in Chinese hamster ovary cells. By deglycosylation analysis it was shown that the difference in size was due to a different type of glycosylation. Biological activity of the fusion protein, as determined by growth stimulation of TF-1 erythroleukemia cells, was less than 15% of that of human recombinant erythropoietin. Upon digestion of the fusion protein with IgA protease, biological activity comparable to that of the recombinant erythropoietin was recovered. Transgenic males and virgin females did not show signs of enhanced erythropoiesis, but lactating females expressing the transgene displayed transient increases in their hematocrit values.     

GnRH molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes). Immunological and chromatographic evidence for the presence of a novel molecular variant

Gonadotropin-releasing hormone (GnRH) molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes), were characterized by gradient reverse phase high performance liquid chromatography (RP-HPLC). Eluted fractions were tested in radioimmunoassays with different antisera. The results show that the brain extract contains three forms of GnRH: one is immunologically and chromatographically similar to cIIGnRH (chicken II), and another is similar to sGnRH (salmon). A third GnRH appears to be chromatographic and immunologically different from the nine other known forms of the vertebrate hormone. This is the only variant present in the pituitary gland.     

The impact of Project 2000

The research study described here was commissioned by the English National Board to examine nursing in the context of Project 2000 implementation. The research team explored the impact of Project 2000 on students, managers and practitioners. Students and diplomates were perceived to be patient-oriented and holistic in approach; basic nursing care was identified as a central role of qualified nurses. Perceptions of nursing shifted as the course progressed to include health promotion, and research and theory as a basis for practice. Aspects of the course valued by students included the broader academic input, interpersonal skills, life sciences, supernumerary status and the challenging approach advocated by the course. Students were concerned about the timing of the biological science modules, which often did not coincide with their practice experiences. Students identified poor course organisation and poor teaching skills of some lecturers as areas for concern. Managers and practitioners identified students as potential agents of change who challenged traditional expectations of newly qualified nurses.     

Health status of the over 60 years of age population and its relationship with sociodemographic factors (ANCO Project)

OBJECTIVE: To describe the health status of a population over 60 years and to study their relationship with several socio-demographic variables. DESIGN: A cross-sectional study, population based. SETTINGS: A community. PARTICIPANTS: A randomized sample of 1,103 non institutionalized people over 60 years living in the city of Cordoba (Spain). MEASUREMENTS AND MAIN RESULTS: By mean of a personal interview at home we used the OARS-MFAQ-VE questionnaire. Low self-rated health was associated with the age, to be female sex, a low cultural background, and a low income. Only 5.2% of the study people do not suffered any illness and 56% state that their health problems are major problems for doing their current activities. 4.9% declared to have some degree of physical incapacity. 3.7% of elderly population has an important cognitive deficit. CONCLUSIONS: The majority of elderly people has good health. Age is related with a poor health. Women have more health problems than men.     

Delay-optimal quorum consensus for distributed systems

Given a set of nodes S, a coterie is a set of pairwise intersecting subsets of S. Each element in a coterie is called a quorum. Mutual exclusion in a distributed system can be achieved if each request is required to gel consensus from a quorum of nodes. This technique of quorum consensus is also used for replicated distributed database systems, and bicoteries and wr-coteries have been defined to capture the requirements of read and write operations in user transactions. The author is interested in finding coteries, bicoteries, and wr-coteries with optimal communication delay. The protocols take into account the network topology. They design delay-optimal quorum consensus protocols for network topologies of trees, rings, and clustered networks