廉州湾海水营养盐组成特征与主要环境因子的关系

根据1998年1月、4月、8月、10月4个航次的调查资料,分析廉州湾海水营养盐组成特征并用回归方法分析营养盐含量与主要环境因子的关系。结果表明,营养盐随季节不同而发生变化,丰水季节,营养盐组成Si：N：P比例明显偏高,枯水季节,营养盐组成比例明显偏低,影响这一特征变化的主要原因是与注入该湾的径流量和污染物有关。无机氮、无机磷、活性硅酸盐与主要环境因子具有明显的相关性,且相关程度随季节不同而发生差异。     

Inhibition of phosphorylcholine binding to antibodies using synthetic peptides

The amino-acid sequence Phe-Tyr-Met-Glu is unique to phosphorylcholine (PC)-binding antibodies. It occurs in the first complementarity-determining region (CDR1) of the immunoglobulin heavy chains in 89% of all the anti-PC myeloma and hybridoma proteins but is not present in 490 other immunoglobulin heavy chains, 854 light chains or in 2,260 other unrelated proteins. This unique tetrapeptide therefore seems to be involved in PC binding. Here we compare the effectiveness of Phe-Tyr-Met-Glu and other structurally related peptides in inhibiting the binding of PC to PC-binding proteins McPC603 and HOPC8. We also test a surface-simulation peptide that was constructed to mimic the combining site of McPC603. Our data suggest that all these peptides inhibit the binding of PC to PC-binding proteins non-specifically and we show by computer modelling that the surface-simulation peptide does not duplicate the combining site of McPC603.     

振动出矿机工作参数电算优化

本文在分析振动出矿动力学问题的基础上,建立了包括放矿生产能力、单位矿量能耗和物料干扰强度在内的三个振动出矿效果衡量指标。应用电子计算机对单轴和双轴惯性振动出矿机分别进行了工作参数最优化分析。室内模型试验的结果表明,本文所提出的最佳工作参数及其实用的计算公式是易行和基本可靠的。·     

薄层扫描法测定通达滴鼻剂中小檗碱的含量

采用双波长薄层扫描法测定通达滴鼻剂中小檗碱的含量，点样量在0．25～2．59μg范围内呈良好的线性关系，平均回收率为98.84％(n=5)。该方法可靠、数据准确、操作简便、易行，可以作为通达滴鼻剂质量控制的方法之一。     

Monoamine oxidase activity in tissues of spontaneously hypertensive rats

Summary Monoamine oxidase (MAO) activity was assayed both in central and peripheral blood vessels of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKR). The activity of MAO in the brain and peripheral vasculature was essentially the same in both SHR and WKR. It can therefore be concluded that central and peripheral vascular MAO activity is not altered in the genetically hypertensive animals.     

新澄杂种西瓜及其亲本的同工酶分析

对良种西瓜“新澄”杂种及其亲本的酯酶、过氧化物酶同工酶进行分析研究的结果表明,杂种与其亲本的同工酶酶谱有显著差异,杂种除了具有双亲的“互补酶带”外,还出现双亲所没有的“杂种酶带”;同时发现杂种优势与酶谱的变化有密切相关.应用同工酶分析法鉴定这种价值昂贵的杂种种子的纯度,有一定的经济价值.     

从“国际法”与国内法——美台安全关系法律基础的演变

蒋介石逃到台湾之后,台湾就一直在寻求美国的保护。1954年美台签订了共同防御条约。随着国际形势 的变化,美国一方面和中国建立外交关系,一方面却抛出《与台湾关系法》,用国内法的形式重新提出了对台湾安全 的关注。     

A novel OFDM transmission scheme with length-adaptive Cyclic Prefix

Conventional OFDM transmission system uses a fixed-length Cyclic Prefix to counteract Inter-Symbol Interferences (ISI) caused by channel delay spreading under wireless mobile environment. This may cause considerable performance deterioration when the CP length is less than the channel RMS delay spread, or may decrease the system power and spectrum efficiency when it is much larger. A novel OFDM transmission scheme is proposed in this paper to adapt the CP length to the variation of channel delay spread. AOFDM-VCPL utilizes the preamble or pilot sub-carriers of each OFDM packet to estimate the channel RMS delay spread; and then uses a criterion to calculate the CP length , which finally affects the OFDM transmitter. As illustrated in the simulation section, by deploying this scheme in a typical wireless environment, the system can transmit at data rate 11.5 Mb/s higher than conventional non-adaptive system while gaining a 0.65 dB power saving at the same BER performance.     

Molecular evolution of FOXP2, a gene involved in speech and language

Language is a uniquely human trait likely to have been a prerequisite for the development of human culture. The ability to develop articulate speech relies on capabilities, such as fine control of the larynx and mouth, that are absent in chimpanzees and other great apes. FOXP2 is the first gene relevant to the human ability to develop language. A point mutation in FOXP2 co-segregates with a disorder in a family in which half of the members have severe articulation difficulties accompanied by linguistic and grammatical impairment. This gene is disrupted by translocation in an unrelated individual who has a similar disorder. Thus, two functional copies of FOXP2 seem to be required for acquisition of normal spoken language. We sequenced the complementary DNAs that encode the FOXP2 protein in the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse, and compared them with the human cDNA. We also investigated intraspecific variation of the human FOXP2 gene. Here we show that human FOXP2 contains changes in amino-acid coding and a pattern of nucleotide polymorphism, which strongly suggest that this gene has been the target of selection during recent human evolution.