简易太阳能手机充电器的设计

选择ICR1211为直流变换器件,并以它为核心设计了一款简易太阳能手机充电器。文中阐述了电路的工作原理,实物测试表明,该充电器工作稳定、可靠,使用灵活。     

系统性红斑狼疮患者血清铁蛋白水平检测

用酶联免疫吸附试验测定２８例系统性红斑狼疮（ＳＬＥ）患者血清铁蛋白水平，结果表明，与正常对照比较ＳＬＥ患者血清铁蛋白水平增高，但治疗前后血清铁蛋白改变无显著性，与疾病活动指数无显著相关性．这些结果提示ＳＬＥ患者存在有异常铁代谢，本文对此进行了讨论．     

Biochemistry of Nitric Oxide

Nitric oxide (NO) a free radical having both cytoprotective as well as tumor promoting agent is formed from l-arginine by converting it to l-citrulline via nitric oxide synthase enzymes. The reaction product of nitric oxide with superoxide generates potent oxidizing agent, peroxynitrite which is the main mediator of tissue and cellular injury. Peroxynitrite is reactive towards many biomolecules which includes amino acids, nucleic acid bases; metal containing compounds, etc. NO metabolites may play a key role in mediating many of the genotoxic/carcinogenic effects as DNA damage, protein or lipid modification, etc. The basic reactions of nitric oxide can be divided as direct effect of the radical where it alone plays a role in either damaging or protecting the cell milieu and an indirect effect in which the byproducts of nitric oxide formed by convergence of two independent radical generating pathways play the role in biological reactions which mainly involve oxidative and nitrosative stress. Nitric oxide is also capable of directly interacting with mitochondria through inhibition of respiration or by permeability transition. Reaction of nitric oxide with metal ions include its direct interaction with the metals or with oxo complexes thereby reducing them to lower valent state. Excessive production of nitric oxide can be studied by inhibiting the synthetic pathway of nitric oxide using both selective or specific nitric oxide synthase inhibitor or non-selective nitric oxide synthase inhibitor with respect to isoforms of nitric oxide.     

基于DDC的锅炉温度控制系统的设计

本次设计主要通过带有A/D、D/A功能的数据采集模块及外围的检测与执行元件,结合试验室所提供的过程控制对象,针对双层锅炉夹套水温为被控参数,设计研究锅炉温度控制系统,完成了系统的锅炉温度控制定值控制。     

Production of a monoclonal antibody against oxytetracycline and its application for oxytetracycline residue detection in shrimp简

A novel monoclonal antibody (MAb) against oxytetracycline (OTC) was generated and characterized. The MAb was used in the development of an enzyme-linked immunosorbant assay (ELISA)-based detection system. An OTC-bovine serum albumin (BSA) conjugate was prepared and used in the immunization of mice. A conventional somatic cell fusion technique was used to generate MAb-secreting hybridomas denoted 2–4F, 7–3G, and 11–11A. An indirect competitive ELISA (icELISA) was applied to measure the sensitivity and specificity of each MAb in terms of its 50% inhibitory concentration (IC50) and percentage of cross-reactivity, respectively. MAb 2–4F exhibited the highest sensitivity, with an IC₅₀ of 7.01 ng/ml. This MAb showed strong cross-reactivity to rolitetracycline, but no cross-reactivity to other unrelated antibiotics. When MAb 2–4F was used to detect OTC from shrimp samples, the recoveries were in the range of 82%–118% for an intra-assay and 96%–113% for an inter-assay. The coefficients of variation of the assays were 3.9%–13.9% and 5.5%–14.9%, respectively.     

政府行为与自主创新:基于供求视角的分析框架

自主创新离不开政府行为,本文从政府支持自主创新的供给和需求角度实证分析了政府直接财政科技投入和政府采购对我国自主创新的影响。研究显示:政府直接财政科技投入和政府采购均对我国自主创新有显著的促进作用。另外,本文还发现,中国的R&D人员和居民消费亦对我国自主创新有正面影响,并且其对自主创新的促进效果要强于政府财政科技投入和政府采购,而出口对自主创新存在负效应。政府直接财政科技投入和政府采购对自主创新的影响表现出明显的地区差异,但其对我国东西部地区的自主创新均产生正面影响。     

Preparation of high-affinity rabbit monoclonal antibodies for ciprofloxacin and development of an indirect competitive ELISA for residues in milk

A convenient competitive enzyme-linked immunosorbent assay (ELISA) for ciprofloxacin (CPFX) was developed by using rabbit monoclonal antibodies (RabMAbs) against a hapten-protein conjugate of CPFX-bovine serum albumin (BSA). The indirect competitive ELISA of CPFX had a concentration at 50% inhibition (IC₅₀) of 1.47 ng/ml and a limit of detection (LOD) of 0.095 ng/ml. The mAb exhibited some cross-reactivity, however, not so high with enrofloxacin (28.8%), ofloxacin (13.1%), norfloxacin (11.0%), fleroxacin (22.6%), and pefloxacin (20.4%). And it showed almost no cross-reactivity with other antibiotics or sulfonamides evaluated in this study. The competitive ELISA kit developed here could be used as a screening tool to detect and control illegal addition of CPFX in food products. This kit had been applied to milk detection and the recovery rates from samples spiked by CPFX were in a range of 63.02%–84.60%, with coefficients of variation of less than 12.2%.     

Investigation on the application of reformed coke oven gas in direct reduction iron production with a mathematical model

To investigate the application of reformed coke oven gas （COG） in producing the direct reduction iron （DRI）, we simulated a countercurrent gas solid moving bed reactor in which the iron ore pellet was reduced by reformed COG. An ordinary differential equation （ODE） was set based on the unreacted shrinking core model considering both mass and energy balances of the reactor. The concentration and temperature profiles of all species within the reactor were obtained by solving the ODE sys tem. The solid conversion and gas utilization were studied by changing gas flow rate, solid flow rate, reactor length, and the ratio of O/CHa to guide the practical application of COG in DRI production. Model results showed that COG was suitable for the DRI production. In order to meet the requirement of the industrial production, the minimum gas flow rate was set as 130,000 Nm3/h, and the maximum production was 90 t/h. The reactor length and the mole ratio x（O）： x（CH4） were depended on the actual industrial situations.     

Exploring student learning approaches on an initial teacher education programme: A comparison of mature learners and direct entry third-level students

This article compares the learning approaches of students on an initial teacher education programme. Using a mixed method approach, the study examines differences between mature learners and direct entry students, across the domains of deep, strategic and surface learning approaches. Following the quantitative phase, group interviews were conducted to gain additional insights into the factors, which impacted learning approach. Significant differences were evident between both cohorts. The key categories that contributed to learning approach included; motivation to learn, collaborative and competitive learning, prior educational experiences and school placement. The findings provide insights into the diversity of student cohorts.     

Is there a role for direct instruction in problem-based learning? Comparing student-constructed versus integrated model answers

Problem-based learning (PBL) requires students to formulate learning issues that need to be answered by studying multiple literature resources. Advocates of high instructional guidance argue that this is too cognitively demanding for students and ineffective for learning. Therefore, we examined the effects of studying an integrated model answer in the self-study phase in PBL. Participants (N = 62) engaged in a simulated group discussion, ending with the establishment of learning issues. Then they either studied integrated model answers to the learning issues, or undertook a standard PBL self-study phase in which students needed to construct their own answers based on multiple literature resources. Higher learning outcomes were obtained for the participants who studied integrated model answers when compared to the participants who constructed their own answers. These higher learning outcomes were obtained with lower investment of self-study and equal investment of mental effort during learning.