基于LPC预测误差DWT的语音基音检测

在对语音信号进行ＬＰＣ分析的基础上，提出了一种有效的语音基音周期检测算法。该算法利用小波变换中著名的Ｍａｌｌａｔ算法逐层分解ＬＰＣ预测误差信号，在最低分辨率的逼近信号中寻找峰值，然后逐层回溯各个分辨率的逼近信号，最后在ＬＰＣ预测误差中确定出峰值，从而求出相应的基音周期。     

Regulation of the retinal interphotoreceptor matrix Na by the retinal pigment epithelium during the light response

We examined the rabbit retinal pigment epithelium (RPE) for Na transport properties which would allow it to buffer undesirable changes in Na concentrations in the interphotoreceptor matrix (IPM) during light and dark cycles. The RPE is selectivity permeable to sodium. Open and short circuit transport studies with RPE indicate a circulating (choroid to retina and back) Na current which does not compromise the electrical integrity of the blood brain barrier but together with the Na permeselectivity is of sufficient magnitude to buffer both upwards and downwards movements of IPM [Na] during light or dark responses.     

Protective effect of Shigyaku-to,a traditional Chinese herbal medicine,on the infection of herpes simplex virus type 1 (HSV-1) in mice

The antiviral activity of Shigyaku-to (TJS-109), a traditional Chinese herbal medicine, was investigated in mice infected with herpes simplex virus type 1 (HSV-1). TJS-109 is a combination of the medicinal plant extracts fromZingiberis siccatum rhizoma,Aconiti tuber andGlycyrrhizae radix in a specific proportion. Mice infected with a 10 LD₅₀ dose of HSV-1 were treated with TJS-109 orally at doses of 1.25 to 20 mg/kg 2 days before, and 1 and 4 days after the infection. The treated groups had 80% (1.25 mg/kg), 40% (5 mg/kg) and 23% (20 mg/kg) mortality rates 25 days after the infection as compared with a 100% mortality rate in control mice treated with saline. When HSV-1 infected mice (recipients) received CD8⁺T cell fractions derived from spleens of mice treated with TJS-109 (donors), 70% of recipients survived, as compared with 0% survivors in the groups of mice treated with saline, B cell fractions, CD4⁺ T cell fractions or macrophage-enriched fractions prepared from the same donors. TJS-109 did not show any virucidal activities against HSV-1 or any virostatic activities on the growth of HSV-1 in Vero cells. These results suggest that TJS-109 protected mice exposed to lethal amounts of HSV-1 through the activation of CD8⁺ T cells.     

A morphometric study of spermatogenesis in the testes of mice of a senescence accelerated strain

The morphometric parameters of spermatogenic cells in a mouse strain prone to accelerated senescence (SAM-P), a novel murine model of spontaneously promoted aging, were compared with those of a SAM resistant strain (SAM-R) after birth until 40 weeks (mean life span of SAM-P). A mixture of gonocytes and spermatogonia were present in the testis in 1-week-old mice, and no gonocytes were observed in 2-week-old mice. At 6 weeks of age, the absolute number of spermatogonia in SAM-P was 27% greater than that in SAM-R, whereas the cell number in 40-week-old SAM-P was 17% less than in SAM-R. Primary spermatocytes were first observed in 3-week-old animals, and the cell numbers in SAM-P at 3, 5 and 6 weeks were 78%, 31% and 25%, respectively, greater than in SAM-R, whereas the cell number in SAM-P at 40 weeks was 30% less than SAM-R. Round spermatids were first observed in all SAM-P at 4 weeks old, but 20% of SAM-r had no spermatids and the rest had only a few. At 5 and 6 weeks old, the absolute numbers of round spermatids in SAM-P was about 34% and 41%, respectively, greater than in SAM-R, whereas the cell number in 40-week-old SAM-P was about 34% less than SAM-R. These results indicate that testicular maturation begins at an earlier age in SAM-P than SAM-R. Furthermore, at the age of 40 weeks signs of testicular deterioration are evident in SAM-P mice only     

Role of hsp70 in cytokine production

Interleukin-1 and tumor necrosis factor-alpha are potent, multifunctional cytokine mediators of inflammation and immune responses that are produced primarily by activated monocytes and macrophages. Three published papers by different groups have shown that heat shock and chemical stress with heavy metal salts or sulfhydryl reagents, all of which induce the expression of heat shock protein 70 (hsp70), concomitantly inhibit the production of these cytokines in human monocytes and mouse macrophages activated by lipopolysaccharide. These papers are reviewed and discussed in some detail. Other studies suggest that various anti-inflammatory drugs, including acetylsalicyclic acid, auranofin and dexamethasone, can also facilitate HSP expression in macrophages. However, while these studies are interesting, it is clear that not a great deal of work has been done and/or published in this area. Since many pharmaceutical companies are developing cytokine synthesis inhibitors as potential anti-inflammatory drugs, one aim of this article is to emphasize that understanding the molecular mechanism(s) that lead to increased HSP expression and decreased cytokine biosynthesis may assist in achieving this goal.     

碘放射性核素在土壤－蔬菜系统中的转移系数

人工引入核电站排放的关键核素￣（１３１）Ｉ，采用γ能谱和总β计数两种方法确定核素在土壤－蔬菜系统中的转移系数。测得核素不同迁移时间、不同生长期的蔬菜、以及土壤中不同核素浓度等各种情况下的转移系数。给出转移系数的频数分布及变异性。γ能谱法测得的￣（１３１）Ｉ在广东土壤－蔬菜系统中转移系数的观察值范围为１．２８×１０￣（－２）～２．１０×１０￣（－１），几何平均值为５．０５×１０￣（－２），几何标准偏差为１．９６．实验中观察到蔬菜棵株大小、不同气候条件等因素对转移系数的影响。     

Calcium/calmodulin-dependent protein kinase II increases glutamate and noradrenaline release from synaptosomes

A variety of evidence indicates that calcium-dependent protein phosphorylation modulates the release of neurotransmitter from nerve terminals. For instance, the injection of rat calcium/calmodulin-dependent protein kinase II (Ca2+/CaM-dependent PK II) into the preterminal digit of the squid giant synapse leads to an increase in the release of a so-far unidentified neurotransmitter induced by presynaptic depolarization. But until now, it has not been demonstrated that Ca2+/CaM-dependent PK II can also regulate neurotransmitter release in the vertebrate nervous system. Here we report that the introduction of Ca2+/CaM-dependent PK II, autoactivated by thiophosphorylation, into rat brain synaptosomes (isolated nerve terminals) increases the initial rate of induced release of two neurotransmitters, glutamate and noradrenaline. We also show that introduction of a selective peptidergic inhibitor of Ca2+/CaM-dependent PK II inhibits the initial rate of induced glutamate release. These results support the hypothesis that activation of Ca2+/CaM-dependent PK II in the nerve terminal removes a constraint on neurotransmitter release.     

A binding site for the T-cell co-receptor CD8 on the alpha 3 domain of HLA-A2

Adhesion measurements between CD8 and 48 point mutants of HLA-A2.1 show that the CD8 alpha-chain binds to the alpha 3 domain of HLA-A2.1. Three clusters of alpha 3 residues contribute to the binding, with an exposed, negatively charged loop (residues 223-229) playing a dominant role. CD8 binding correlates with cytotoxic T-cell recognition and sensitivity to inhibition by anti-CD8 antibodies. Impaired alloreactive T-cell recognition of an HLA-A2.1 mutant with reduced affinity for CD8 is not restored by functional CD8 binding sites on an antigenically irrelevant class I molecule. Therefore, complexes of CD8 and the T-cell receptor bound to the same class I major histocompatibility complex molecule seem to be necessary for T-cell activation.