Nature of the molecular heterogeneity of human leukocyte interferon

The existence of two components of human leukocyte interferon has been recently reported. In the present study, the nature of this molecular heterogeneity was explored by affinity chromatography on immobilized micro- and macroligands, ion-exchange chromatography, and molecular sieving. Chromatography on a series of alkyl-agarose adsorbents shows, for the first time, the intrinsic hydrophobicity of human leukocyte interferon. Additionally, the separation of two interferon components is achieved by use of the alkyl-agarose as well as by the omega-aminoalkyl-agarose adsorbents. Clear-cut separation of the two components was also achieved by chromatography on BSA-CH-Sepharose and on DEAE-Bio Gel A. An important feature of these separations is that they do not require the use of denaturing conditions. The molecular weights of the leukocyte interferon components, as determined on Sephadex G-75, are quite similar or identical, approximately 26,000. Thus, the molecular heterogeneity of human leukocyte interferon can be attributed, at least in part, to differences in the hydrophobicity and ionic properties of its two components.     

The effects of sodium ricinoleate on small intestinal function and structure

The mechanism of hydroxy fatty acid-induced secretion was investigated in perfused hamster small intestine in vivo. Sodium ricinoleate at an 8-mM concentration resulted in not only secretion of water and sodium, but an increase in intestinal clearance of inulin and a 16,000 mol wt dextran as well. A concentration of ricinoleate (2 mM) which did not affect water transport, however, did not alter intestinal permeability. Ricinoleate-induced intestinal secretion was also accompanied by increased mucosal cell exfoliation as measured by the appearance of DNA in the perfusate and by apparent injury to epithelial cell membranes as judged by measurement of sucrase activity and phospholipid in cell-free aliquots of luminal fluid. Light and electron microscopic studies demonstrated substantial mucosal architectural changes with 8 mM ricinoleate with villus shortening and injury to epithelial cells at the villus tips. In contrast, cholera enterotoxin caused marked secretion of sodium and water, presumably by a cyclic AMP mechanism, but did not alter inulin clearance or enhance DNA or sucrase appearance in the lumen. These studies suggest that at least a component of ricinoleate-induced intestinal secretion is related to structural alterations of the mucosa.     

Comparative studies of social behavior in Callicebus and Saimiri: strength and specificity of attraction between male-female cagemates

The strength and specificity of attraction between male and female cagemates was compared in Saimiri and Callicebus, using paired-comparison and single-stimulus methods of testing. Results from both methods showed that the attraction to the cagemate was stronger and more specific in Callicebus than in Saimiri. Sex differences were more pronounced in Saimiri than in Callicebus. Squirrel monkey females were more strongly attracted to strangers than were males and they clearly preferred female strangers over male strangers or their male cagemates.     

一种新型压电式双向无阀微泵的研制

采用氧化、光刻、腐蚀、键合等MEMS技术,研制了一种硅基压电式双向无阀微泵,泵的外形尺寸为30×14×3 mm3,泵腔体体积约10 mm3.通过大量试验测试,得到了泵压、流量与工作频率、波形、电压幅值之间的关系.当工作电压为110 V、频率为40 Hz时,微泵的正向最大泵压为120 mm水柱,频率为50-90 Hz时,最大流量70μl/min;当频率为35 Hz时,微泵的反向最大泵压为70 mm水柱,最大流量56μl/min.     

吸附EDTA活性炭的电化学再生(英文)

采用吸附饱和EDTA的活性炭作为三维电极反应器中的粒子电极,多次使用后采用电化学方法对其再生。通过对吸附饱和EDTA的活性炭和多次电解使用后的活性炭的红外光谱谱图的分析得出,EDTA被活性炭吸附后产生甘氨酸H2NCH2COOH,通过N—H键生成一种永久性占据活性炭活性点的非催化活性缔合物,导致其催化活性消失,降解效率下降。采用电解方法使活性炭再生,得出活性炭的最佳活化条件为:电流100～300mA,溶液电导率1.39mS/cm,pH值6.0～8.0,电解1h可以使活性炭恢复活性,电解后有机物的残余TOC浓度低于10mg/L(初始浓度为200mg/L)。     

Determinant in human immunodeficiency virus type 1 for efficient replication under cytokine-induced CD4(+) T-helper 1 (Th1)- and Th2-type conditions

Cytokines are potent stimuli for CD4(+)-T-cell differentiation. Among them, interleukin-12 (IL-12) and IL-4 induce naive CD4(+) T cells to become T-helper 1 (Th1) or Th2 cells, respectively. In this study we found that macrophage-tropic human immunodeficiency virus type 1 (HIV-1) strains replicated more efficiently in IL-12-induced Th1-type cultures derived from normal CD4(+) T cells than did T-cell-line-tropic (T-tropic) strains. In contrast, T-tropic strains preferentially infected IL-4-induced Th2-type cultures derived from the same donor CD4(+) T cells. Additional studies using chimeric viruses demonstrated that the V3 region of HIV-1 gp120 was the principal determinant for efficiency of replication. Cell fusion analysis showed that cells expressing envelope protein from a T-tropic strain effectively fused with IL-4-induced Th2-type culture cells. Flow cytometric analysis showed that the level of CCR5 expression was higher on IL-12-induced Th1-type culture cells, whereas CXCR4 was highly expressed on IL-4-induced Th2-type culture cells, although a low level of CXCR4 expression was observed on IL-12-induced Th1-type culture cells. These results indicate that HIV-1 isolates exhibit differences in the ability to infect CD4(+)-T-cell subsets such as Th1 or Th2 cells and that this difference may partly correlate with the expression of particular chemokine receptors on these cells. The findings suggest that immunological conditions are one of the factors responsible for inducing selection of HIV-1 strains.     

微乳形成与应用研究进展

概述了微乳的形成及其应用研究进展,介绍了农药微乳剂的研究和应用现状,并对此进行了评述和展望.     

Mechanically Driven Alloying and Structural Evolution of Nanocrystalline Fe_(60)Cu_(40) Powder

Highly supersaturated nanocrystalline fcc Fe60Cu40 alloy has been prepared by mechanical alloying of elemental powders. The phase transformation is monitored by X-ray diffraction (XRD),Mossbauer spectroscopy and extended X-ray absorption fine structure (EXAFS). The powder obtained after milling is of single fcc structure with grain size of nanometer order. The Mossbauer spectra of the milled powder can be fitted by two subspectra whose hyperfine magnetic fields are 16 MA/m and 20 MA/m while that of pure Fe disappeared. EXAFS results show that the radial structure function (RSF) of Fe K-edge changed drastically and finally became similar to that of reference Cu K-edge, while that of Cu K-edge nearly keeps unchanged in the process of milling. These imply that bcc Fe really transforms to fcc structure and alloying between Fe and Cu occurs truly on an atomic scale. EXAFS results indicate that iron atoms tend to segregate at the boundaries and Cu atoms are rich in the fcc lattice. Annealing experiments show that the Fe atoms at the interfaces are easy to cluster to α-Fe at a lower temperature, whereas the iron atoms in the lattice will form γ-Fe first at temperature above 350℃, and then transform to bcc Fe