蜂窝结构在面内剪力作用下的变形模式

本文建立了等壁厚与非等壁厚蜂窝结构在面内剪力作用下的变形模式,导出了等壁厚与非等壁厚蜂窝结构的面内折合剪切模量G_(xy)的计算公式。     

Suppression of natural killer cell activity in mouse spleen lymphocytes by several dopamine receptor antagonists

The effects of dopaminergic receptor inhibitors such as thiothixine (D₁/D₂), fluphenazine (D₁/D₂), trifluoperazine (D₁/D₂), pimozide (D₂), flupenthixol (D₁/D₂), (+/–)-SKF 83566 (D₁), and spiperone (D₂) on splenic natural killer (NK) cell cytotoxic activities were assessed in vitro using mouse spleen lymphocytes or enriched NK cells. Both the activities of the splenic NK cell cytotoxicity and the effector-target cell conjugation were suppressed by thiothixine, fluphenazine, and trifluoperazine at concentrations from 2.64 to 14.78 M. In addition, the augmentation of the cytolytic activity of NK cells induced by interferon- or interleukin-2 was antagonized by pretreatment with these neuroleptic compounds. However, neither the splenic NK cell cytotoxicity nor the effector-target cell conjugation were affected by treatment with other neuroleptic compounds such as pimozide, flupenthixol, (+/–)-SKF 83566, and spiperone. Thus, it appears that neuroleptic compounds such as thiothixine, fluphenazine, and trifluoperazine may act through the mechanisms other than a dopaminergic pathway to affect the NK cell-target cell interaction.     

Histochemical evidence for the presence of dipeptidylpeptidase IV in the Schwann cells of skin uymyelinated axons

Summary DPP IV activity was localized in the nerve fascicles of cat glabrous skin at light and electron microscope levels. The observation that the DPP IV end product was restricted to the axon-Schwann cell interface suggests that this enzyme may be involved in the interactions between unmyelinated axons and their Schwann cells.17 November 1986     

Hyperthermia-induced apoptosis and the inhibition of DNA laddering by zinc supplementation and withdrawal of calcium and magnesium in suspension culture of tobacco cells

In the present paper we report examination of stereotypic hallmarks of apoptosis in heat-treated tobacco cells. Hyperthermia (44 °C, 4 h) caused apoptosis in 53.6% of cells when assayed 24 h after heat treatment. The induction of apoptosis by heat treatment was confirmed by flow cytometric assay. Cytological observations revealed condensation of the cytoplasm and nucleus, as well as nuclear collapse. DNA ladders were observed in DNA extracted from heat-treated cells, whereas DNA from control cells remained undegraded. The terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay revealed that 51.8% of the heat-treated cells (44 °C, 4 h) show positive reaction after a 24-h recovery. When cells were cultured in a medium supplemented with 0.4–5.0 mM ZnSO₄, internucleosomal DNA fragmentation induced by heat shock was completely negated. Strikingly, when cells were cultured in Ca²⁺ and/or Mg²⁺ free medium for 44 h followed by heat treatment, DNA laddering was not observed. The results suggest hyperthermia-induced apoptosis and a correlation between the regula tion of endonucleases and heat shock signal in apoptotic tobacco cells. Received 17 September 1998; received after revision 4 January 1999; accepted 4 January 1999     

交联聚丙烯酰胺在锌锰干电池中的应用

在锌锰干电池正极中加入交联聚丙烯酰胺作为保水剂,使电池放电性能提高和储存寿命延长。     

Some cellular and molecular properties of abscisic acid: its particular involvement in growing plant roots

Several characteristics of the plant hormone abscisic acid (ABA) are critically discussed, more or less directly, in relation to the extension of root cells. A few topics have been selected some biochemical characteristics of ABA (chemical structure, metabolism), inhibiting-β complex, inhibiting regulators from root caps, endogenous ABA in growing roots (ABA gradients, microsurgical experiments, light effects), applied ABA on elongating roots, ABA and indol-3yl acetic acid (IAA) interactions (root growth, proton extrusion, hormone transport, auxin herbicides), ABA effect on the root cell cycle, ABA and drought cells of elongating roots [water deficit conditions, IAA and jasmonic acid (JA) as ‘stress hormones’ other than ABA, gene expression]. Received 28 January 1998; received after revision 20 April 1998; accepted 21 April 1998     

鳙鱼卵子成熟过程的细胞学研究

本文研究了镛鱼第Ⅳ时相卵母细胞发育成熟为第Ⅴ时相成熟卵子的细胞学演变程序。水温25—26度,镛鱼卵母细胞历经15(1/2)时,完成第Ⅳ时相到第Ⅴ时相的过渡,完成成熟排卵。在卵子成熟过程中,卵内各种有形物质发生有规律的移动和安排。注射后3小时,卵核开始移动。至注射后12(1/2)小时,胚泡破裂,相继产生两次成熟星光。注射后15(1/2)小时,卵核完成第一次成熟分裂,进入第二次成熟分裂中期。随着卵母细胞的成熟,精孔细胞逐渐溶解,最终消失殆尽,受精孔敞开,细胞质汇集动物性极,形成胚基。最终,成熟卵子突破滤泡膜,游离排出体外。本文还对家鱼卵细胞成熟过程中的有关基础理论问题进行了分析讨论。     

植物生长调节剂对几种海洋单细胞藻类增殖的影响

在室内温度16—26℃、光强4800—6500lux培养条件下,研究了3种植物生长调节剂分别对3种海洋单细胞藻类生长的影响。结果表明,在0.005×10_(-6)-1.0×10_(-6)浓度范围内,植物生长调节剂均能促进藻类细胞增殖。其中三十烷醇促进盐沼杜氏藻细胞增殖的最佳浓度为0.1×10_(-6),对巴夫藻的最佳浓度为0.01×10_(-6);生长素2,4-D促进巴夫藻增殖的最佳浓度为0.5×10_(-6);细胞分裂素6-BA促进球等鞭金藻增殖的最佳浓度为1.0×10_(-6)。在接种后第二和第三天植物生长调节剂对藻细胞的促进作用就明显地表现出来,大大缩短了延缓期而使指数生长期提前。     

Novel photoelectrochromic cells fabricated with wirelike photo-electrode

A novel structure of photoelectrochromic cell fabricated with titanium wirelike photo-electrode is in- troduced in this paper. The transmittance spectra show that average transmittance of devices is 68.0% （from 400 to 1100 nm） at bleached state and 26.1% （from 400 to 1100 nm） at colored state, respectively. And the maximal photopic transmittance of the device varies from 81.9% （bleached state） to 30.3% （colored state） at 736 nm. Compared with traditional devices, the spectral response range is improved obviously, which solves the problem of lower transmittance at bleached state for traditional devices.