基于免疫机制的径向基函数网络动态训练方法

提出了一种针对动态系统的两级径向基函数（RBF）网络训练方法.该方法借鉴自然免疫系统的动态特性和自适应处理能力,将RBF网络的隐层节点分为粗、细拟合节点,分别对动态系统中的稳定部分和突变部分作不同强度的训练.通过自适应免疫机制,较大地降低了计算复杂度,提高了系统的动态追踪能力.仿真结果表明,所提出的方法能较好地平衡训练精度与收敛速度的矛盾,达到了很高的性能.
     

Circadian pacemaker does not arrest in deep hibernation. Evidence for desynchronization from the light cycle

Summary A freerunning rhythm of locomotor activity was observed between hibernation bouts in Turkish hamsters (Mesocricetus brandti) kept in 10L:14D light-dark cycles at 10±1°C. The data further indicate an influence of natural hypothermia upon the circadian system and its ability to entrain to light-dark cycles.     

具有免疫体亲近性的遗传算法及其应用

遗传算法处理具有离散变量的优化问题及网络问题是比较有效的，但在此算法时，容易产生限于局部的最优解，本文根据生物体的免疫体具有亲近性的特征，改进了遗传算法，并应用改进后的算法，求解旅行商问题。     

DNA fragmentation in leukocytes following subacute lowdose nerve agent exposure

The objective of the present study was to determine levels of DNA fragmentation in blood leukocytes from guinea pigs by single-cell gel electrophoresis (comet assay) after exposure to the chemical warfare nerve agent (CWNA), soman, at doses ranging from 0.1 LD₅₀ to 0.4 LD₅₀, once per day for either 5 or 10 days. Post-exposure recovery periods ranged from 0 to 17 days. Leukocytes were imaged from each animal, and the images analyzed by computer. Data obtained for exposure to soman demonstrated significant increases in DNA fragmentation in circulating leukocytes in CWNA-treated guinea pigs compared with saline-injected control animals at all doses and time points examined. Notably, significantly increased DNA fragmentation was observed in leukocytes 17 days after cessation of soman exposure. Our findings demonstrate that leukocyte DNA fragmentation assays may provide a sensitive biomarker for low-dose CWNA exposure.Received 29 July 2003; accepted 14 August 2003     

HLA－G inhibits xenogenetic cytotoxicity mediated by human NK cells and T lymphocytes against PECs

In order to investigate whether the non-classical HLA-G class I molecule protects the prcine endothelial cells(PECs)from the lysis mediated by human immune cells in pig to human discordant xenotransplantation,we have cloned HLA-G cDNA from a human placents by RT-PCR.Mammalian expression vector,pEFG-neo,was constructed by insertion of HLA-G cDNA in pEF-neo.We obtained efficiently expressed PECs by stable transfection.Cytotoxicity assay showed that overexpression of HLA-G on PECs was sufficient to inhibit human NK-92 cell lysis.The level of lysis was equal to or less than that of the lysis of human umbilical vein endothelial cells mediated by human NK-92 cells.It also indicated that HLA-G inhibited the lysis of PECs mediated by xeno-antigen specific T lymphocytes.The reduction of lysis ranged between 59.1% and 88.9A%.These findings suggest that the transgenic approach to overexpress HLA-G is believed to be a new immunotherapy in overconing the immune rejections in xenotransplantion,including delayed xenograft rejection and cell-mediated rejection.     

甲亢患者双特异性免疫复合物的研究

采用捕捉法ELISA,检测108例亢患者的抗体／补体类双特异性免疫合（Ig-C3-TCIC）和抗体／抗体类双特异性免疫复合物（Ig/Ig-TCIC),结果发现,甲亢患者除了C3／IgA-tcic含量显著高于健康人,C3／IgM-TCIC与健康人无显著性差异外,IgM/C3-TCIC、IgG/C3-TCIC、IgA/C3-TCIC和C3／IgG－TCIC的含量均显著低于健康人;各类Ig/Ig－含量,除IgA/IgM-TCIC与健康人无显著差异外,其余均显著高于健康人,结果表明,甲亢患者排除“异己”原的能力低下,而免疫调节水平紊乱,从而出现过高的免疫应答,也证明甲亢患者存在整体的和细胞免疫紊乱。     

Regular oscillations in suspensions of a putatively chaotic mutant ofDictyostelium discoideum

Summary We have tested the light-scattering properties of suspensions of theDictyostelium discoideum mutantHH201 derived from the mutantFr17. Previous studies indicated thatHH201 andFr17 possess highly irregular rhythmic properties which might represent aperiodic oscillations, i.e. chaos. We report that the former mutant can display regular oscillatory behavior. Possible explanations for this result are discussed, including that of a transition from chaotic to periodic behavior resulting from some parameter change or from strong intercellular coupling in cell suspensions.     

The contribution of extrapineal sites of melatonin synthesis to circulating melatonin levels in higher vertebrates

While the production of melatonin in higher vertebrates occurs in other organs and tissues besides the pineal, the contribution of extrapineal sites of melatonin synthesis such as the retina, the Harderian glands and the gut to circulating melatonin levels is still a matter of debate. The amount of melatonin found in the gastrointestinal tract is much higher than in any other organ including the pineal and the gut appears to make a significant contribution to circulating melatonin at least under certain conditions. The gut has been identified to be the major source of the elevated plasma concentrations of melatonin seen after tryptophan administration and of the changes of circulating melatonin level induced by the feeding regime. Whereas the circadian and circannual fluctuations of the concentration of melatonin in the blood seem to be triggered by changes of the photoenvironment and its effect of pineal melatonin formation, basal daytime melatonin levels and the extent of their elevation at nighttime appear to be additionally controlled by nutritional factors, such as the amount and the composition of ingested food and therefore availability of tryptophan as a rate-limiting precursor of melatonin formation by the enterochromaffin cells of the gastrointestinal tract.     

Acclimatization effect on the evening fall in core temperature under the influence of two types of clothing

This paper reports the effect of acclimatization on the evening fall in core temperature under the influence of two different types of clothing. Two groups of subjects dressed in either knee-length skirts or full trousers during the daytime for the three months from April to June. To compare the circadian rhythm of core temperature, the experiments were carried out before and after the three month program of acclimatization. It was found that the subjects who had worn knee-length skirts showed lower rectal temperatures during the nighttime and a bigger amplitude of circadian rhythm in July than in March.