可锻铸铁热浸镀锌合理温度的探讨

目前国内可锻铸铁件热镀锌温度一般是580～640℃,与国外相比高出了100～200℃。根据对可锻铸铁件在460～620℃期间锌铁反应的测定和镀层的结构分析,结合我国目前热镀锌工艺的不足,讨论在生产上如何选择合理的温度和控制热镀锌质量。     

Myelin phagocytosis by macrophages and nonmacrophages during Wallerian degeneration

The literature concerning Schwann cells (SCs) and macrophages in myelin phagocytosis during Wallerian degeneration is reviewed. SCs carry out the first step in the removal of myelin by segmenting myelin and then incorporating the degraded myelin. The recruited macrophages then join in the myelin-phagocytosis event, appearing to make full use of their original phagocyte abilities until the end of myelin clearance. The molecular mechanisms of the two cells underlying myelin phagocytosis are thought to be different; myelin phagocytosis by SCs being lectin-mediated, i.e., opsonin-independent, whereas that of macrophages is mainly opsonin-dependent. It is important to note that SCs and macrophages cooperatively accomplish myelin phagocytosis.     

Peptides from the N-terminal end of bovine lactoferrin induce apoptosis in human leukemic (HL-60) cells

To determine the effects of the multifunctional iron-binding glycoprotein, lactoferrin (LF) and related compounds on the growth of leukemic cells, human myeloid leukemic cells (HL-60) were exposed to bovine lactoferrin (bLF) and proteolytic hydrolysates of bLF. Pepsin hydrolysates of bLF showed a greater growth suppressive effect than tryptic hydrolysates or mature bLF. Four peptides with proliferation inhibition activity were purified from pepsin hydrolysates by ion-exchange chromatography, reverse-phase HPLC, and gel-filtration. All peptides were from the N-terminal end, in a region where lactoferricin B (Lfcin B), an antibacterial peptide, is located. Among the four peptides, peptide 1 (pep1) was found to exhibit highest activity and corresponded to residues 17 to 38 of bLF, with a molecular weight of 2753.88. The IC50 value of this peptide was 6.3 micrograms/ml. Three other peptides were less active and corresponded to sequences 1 to 16 and 45 to 48, linked by disulfide-bridge (pep2, molecular mass of 2430.13), 1 to 15 and 45 to 46 linked by disulfide bridge (pep3, molecular mass of 2017,92) and from residues 1 to 13 (pep4, molecular mass of 1558.73). Cell proliferation inhibition activity of the peptides was thought to be due to induction of apoptosis, which was evaluated by DNA ladder formation, DNA fragmentation, enhanced expression of phosphatidyl serine, and morphological changes. The IC50 values of the three peptides were confirmed using synthetic peptides and were consistent with those of purified peptides.     

基于USB的多路输入输出模块设计

USB总线是一种新型的串行总线，即插即用、可热插拔、最多同时可连接127个设备，尤其是USB2．0规范的提出，使得传输速率最高可以达到480Mbps且具有向下兼容的特征。通过对USB2．0规范的研究，结合实际工作介绍了基于USB总线的多路输入输出模块设计。利用CYPRESS公司的USB2．0控制芯片EZ-USB FX2实现了USB接口电路设计，并解决了多个FPGA之间的通信问题。     

12C6+离子束照射不同肿瘤细胞显示重离子治疗癌症的明显优势

通过观察两种人恶性肿瘤细胞(人肝癌细胞SMMC-7721和人黑色素瘤细胞A375)对高LET12C6 离子和γ射线辐照的敏感性及其差异,考察重离子治疗肿瘤的可行性及优势.以这两种体外培养的来源于人体不同组织的具有高辐射抗性的恶性肿瘤细胞为实验对象,分别进行12C6 和γ射线0-6Gy内不同剂量点的单次和分次照射,采用克隆存活法统计细胞的存活分数.结果显示,无论是单次还是分次照射,12C6 照射后两种细胞的存活分数均明显低于γ射线照射,而且两种细胞的辐射敏感性差异明显降低,同时分次照射细胞的存活分数没有明显提高.结果表明,高LET重离子照射对肿瘤细胞能明显提高杀伤能力,同时降低了不同细胞辐射敏感性的差异且导致细胞低的修复.以上特点与重离子剂量深度分布相结合,使得重离子在治疗肿瘤时具有特殊的优势.     

生物性组织工程血管支架的制备及其内皮化研究

研究经乙二醇缩水甘油醚（EX-810）处理的猪动脉的性能特点,为构建组织工程化血管提供理想支架材料,并在体外实现其内皮化.用EX-810处理猪动脉7 min～72 h.所获材料进行形态学观察并测定交联指数和力学性能.在体外培养、扩增人脐静脉内皮细胞,随后种植培养于四组不同改性的材料表面并用MTT法检测细胞活性;最后用加压铺坪法将其种植到经赖氨酸处理并复合I型胶原的EX-810交联血管支架材料内表面,体外静态培养7天,取样行形态学检测及第Ⅷ因子相关抗原检测.结果显示EX-810既能有效去除和降低组织中产生抗原性的细胞成分和自由氨基,又保持了血管总体组织构架完整;经它处理的血管组织柔韧性好、接近天然血管组织,在各项力学性能方面也与天然血管组织相似;本材料经用赖氨酸处理并复合I型胶原后细胞毒性小,与细胞亲和性高,人脐静脉内皮细胞在其内表面能较好的生长增殖,容易内皮化.     

利用废旧干电池制备Mn-Zn铁氧体前躯体的研究

采用酸溶解法将废旧电池作溶解处理以获得含有锰、锌、铁、铜和镍等金属离子的混合溶液，并通过添加铁粉以除去混合溶液中的铜、镍，以及汞杂质，获得了锰、锌和铁的混合溶液．根据锰锌铁氧体的组成对所得溶液进行调整，采用共沉淀的方法合成了锰锌铁氧体的前躯体．研究表明：利用该方法无需将干电池中的各种金属离子分离，通过调整直接合成锰锌铁氧体的前躯体，从而在解决目前大量废旧电池回收后的再利用问题、实现废旧电池无害化和资源化的同时，为铁氧体的生产提供了一个新的原料来源，具有较好的应用前景．     

微小卫星太阳电池阵的设计计算方法研究

通过全面分析太阳电池的种类和选择,并对影响太阳电池阵的各种因素进行讨论,提出了微小卫星太阳电池阵的设计方法。推导出了基于单圈能量平衡和多圈能量平衡的计算公式,并计算出所需太阳电池阵的面积。设计及计算结果表明:该算法用于微小卫星太阳电池阵的设计与计算是可行的。     

色素增感太阳能电池电解质的研究进展

介绍了色素增感太阳能电池基本结构及原理;综述了色素增感太阳能电池电解质的研究进展及离子液体在电解质中的应用;分析了电解质对色素增感太阳能电池的影响;展望了其应用前景.     

Effects of Photo‐oxidation on the Performance of Poly[2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylene vinylene]:[6,6]‐Phenyl C61‐Butyric Acid Methyl Ester Solar Cells

A study of the photo‐oxidation of films of poly[2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylene vinylene] (MDMO‐PPV) blended with [6,6]‐phenyl C₆₁‐butyric acid methyl ester (PCBM), and solar cells based thereon, is presented. Solar‐cell performance is degraded primarily through loss in short‐circuit current density, J_SC. The effect of the same photodegradation treatment on the optical‐absorption, charge‐recombination, and charge‐transport properties of the active layer is studied. It is concluded that the loss in J_SC is primarily due to a reduction in charge‐carrier mobility, owing to the creation of more deep traps in the polymer during photo‐oxidation. Recombination is slowed down by the degradation and cannot therefore explain the loss in photocurrent. Optical absorption is reduced by photo‐bleaching, but the size of this effect alone is insufficient to explain the loss in device photocurrent.