眩晕73例的诊治观察

<正> 眩晕是临床比较常见的一个病症。对于眩晕的病情轻重和治疗效果的评定,主要依靠病人的主诉与医生的判断,目前还没有客观指标。为此,我们住中医辨证治疗眩晕的研究中,用平衡仪对73例眩晕患者进行了平衡试验观察,现将观察结果报告于下。方法和结果一、观察方法眩晕的检测工具为平衡仪(又称重心仪)Gravicorder,由检测平台和放大器二部分组成。检测平台是一块铸铝板(800×800×200毫米~3),它的四角放在四个负荷传感器(BLR-1

水生植物凤眼莲的种内基因型差异与入侵模式

原产于亚马逊河流域的水生植物凤眼莲（Eichhornia crassipes）在花部结构上有三种花型（L、M和S），故其配殖系统（mating system）为典型的三型花柱（tristyly）。但在入侵地区，它却常只有M和L两种花型，其中尤以M型占据绝对优势，使有性繁殖水平大为下降。为了解释凤眼莲在入侵过程中，花型频率为何发生变化以及该变化对其在入侵地的适应性进化上有何影响，作者在中国西南的两个居群中连续两年开展了野外生长和人工授粉实验，对比分析水面和泥地两类不同生境中M和L在克隆生长、生物量积累以及有性繁殖水平等方面的异同，并利用RAPD、 ISSR片段比较了具M型和L型花植物个体间的遗传变异水平。对三型花柱这一长期引人注目的遗传模式的分子位点也尝试了连锁片段的克隆和测序。 克隆生长的对比实验发现，在2004年，漂浮生长的M个体平均克隆分株数为25.37，L为21.20，前者显示较强的克隆生长能力（t＝2.252， P< 0.05）;2005年的实验再次证实M（每个个体19.83个分株）比L（每个个体15.53分株）表现出了显著较强的克隆优势（t＝2.631，P<0.001）。M较L多产生克隆约24%。 但在岸边泥地上固着生长时，2004年L个体平均克隆分株为16.20，M 为10.17个分株。L表现出了更强的克隆生长能力（t＝4.788，p<0.001），与漂浮生长状况下的情形恰恰相反，暗示M与L个体可能存在一定的生态位分化。这种分化可能是在入侵过程中形成的，也可能反映了原产地亚马孙流域旱涝交替造成的固着生长与漂浮生长交替发生的种内适应性。 生物量（干重）的对比分析发现，M个体在漂浮生长和固着生长的情况下都比L有着更高的生物量积累（漂浮生长实验：t＝6.173，p<0.005（2004年）;t＝6.99，p<0.001（2005年）。固着生长实验：t＝4.029，p<0.001）。生物量对凤眼莲的竞争和过冬有着一定的作用，因此较大的生物量积累可能是M个体在当地气候和环境中逐渐适应的一个结果。 有性繁殖的实验包括了实验个体的花序数与花朵数、自交与异交人工授粉的结实情况以及种子萌发率等方面的对比分析。结果表明，虽然M和L个体在花序数和花朵数上不存在显著差异，但是M个体在自交和异交的种子产量上比L略高，尤其是自交的种子产量，M显著高于L（M平均每个蒴果的自交种子产量为139.8，L为76.2）。以各100粒种子进行萌发实验，发现两花型之间在种子萌发率上不存在显著差异。对于M而言，其自交种子产量远大于异交种子产量 （139.8 vs. 93.3），且种子萌发率也略大于异交的种子萌发率（自交种子萌发率45.47％，异交种子萌发率 30.73％）。结合以上的实验结果，本文认为M基因型优势的形成可能与M个体与当地环境长期适应导致的生长与繁殖 上的优势有关。M的本地适应性是建立在特定的遗传背景上时，异交反而会破坏这种遗传组合，造成远交衰退。 对40个M和30个L个体进行20个RAPD引物和20个ISSR引物的遗传分析时发现，所有个体在RAPD表型上没有区别，但是在M中出现了3个ISSR表型，在L中出现了2个ISSR表型。本文还尝试利用RAPD技术扫描与三型花柱的遗传位点连锁的DNA片段。在146个RAPD随机引物中，初步发现两个候选片段，一个750bp，另一个2 000bp;已对它们进行了克隆、测序。 这些初步实验表明凤眼莲在我国的入侵可能伴随着基因型的差异表现和居群遗传分化，这种基因型的差异表现对该植物的成功入侵具有作用。其中，花型为M的个体的优势生长解释了该花型在中国分布区内的主导地位。推测该生长优势的遗传基础可能来源于基因组内较高的杂合子水平和在入侵地较长的适应历史，但最终结论尚有待进一步的实验证据。

The Effects of Visual Object Size in The Depth Perception in KM Mouse

Whether mice perceive the depth of space dependent on the visual size of object targets was explored when visual cues such as perspective and partial occlusion in space were excluded. A mouse was placed on a platform the height of which is adjustable. The platform located inside a box in which all other walls were dark exception its bottom through that light was projected as a sole visual cue. The visual object cue was composed of 4x4 grids to allow a mouse estimating the distance of the platform relative to the grids. Three sizes of grids reduced in a proportion of 2/3 and seven distances with an equal interval between the platform and the grids at the bottom were applied in the experiments. The duration of a mouse staying on the platform at each height was recorded when the different sizes of the grids were presented randomly to test whether the Judgment of the mouse for the depth of the platform from the bottom was affected by the size information of the visual target. The results from all conditions of three object sizes show that time of mice staying on the platform became longer with the increase in height. In distance of 20 similar to 30 cm, the mice did not use the size information of a target to judge the depth, while mainly used the information of binocular disparity. In distance less than 20 cm or more than 30 cm, however, especially in much higher distance 50 cm, 60 cm and 70 cm, the mice were able to use the size information to do so in order to compensate the lack of binocular disparity information from both eyes. Because the mice have only 1/3 of the visual field that is binocular. This behavioral paradigm established in the current study is a useful model and can be applied to the experiments using transgenic mouse as an animal model to investigate the relationships between behaviors and gene functions.

Anomalous Pressure Behavior of N-Cluster Emissions in GaAs0.973Sb0.022N0.005

Photoluminescence of GaAs0.973Sb0.022N0.005 is investigated at different temperatures and pressures. Both the alloy band edge and the N-related emissions, which show different temperature and pressure dependences, are observed. The pressure coefficients obtained in the pressure range 0-1.4GPa for the band edge and N-related emissions are 67 and 45 meV/GPa, respectively. The N-related emissions shift to a higher energy in the lower pressure range and then begin to redshift at about 8.5 GPa. This redshift is possibly caused by the increase of the X-valley component in the N-related states with increasing pressure.

MnSi similar to 1.73 grown on silicon with mass-analyzed low energy dual ion beam epitaxy technique

Semiconducting manganese silicide, Mn27Si47 and Mn15Si26, were obtained using mass-analyzed low energy dual ion beam epitaxy technique, Auger electron spectroscopy depth profiles showed that some of the Mn ions were deposited on single-crystal silicon substrate and formed a 37.5 nm thick Mn film, and the other Mn ions were successfully implanted into the Si substrate with the implantation depth of 618 nm. Some samples were annealed in the atmosphere of flowing N-2 at 840 degreesC. X-ray diffraction measurements showed that the annealing was beneficial to the formation of Mn27Si47 and Mn15Si26 (C) 2001 Published by Elsevier Science B.V.

Development of expressed sequence tags from the bay scallop, Argopecten irradians irradians

The bay scallop, Argopecten irradians irradians, introduced from North America, has become one of the most important aquaculture species in China. Inan effort to identify scallop genes involved in host defense, a high-quality cDNA library was constructed from whole body tissues of the bay scallop. A total of 5828 successful sequencing reactions yielded 4995 expressed sequence tags (ESTs) longer than 100 bp. Cluster and assembly analyses of the ESTs identified 637 contigs (consisting of 2853 sequences) and 2142 singletons, totaling 2779 unique sequences. Basic Local Alignment Search Tool (BLAST) analysis showed that the majority (73%) of the unique sequences had no significant homology (E-value >= 0.005) to sequences in GenBank. Among the 748 sequences with significant GenBank matches, 160 (21.4%) were for genes related to metabolism, 131 (17.5%) for cell/organism defense, 124 (16.6%) for gene/protein expression, 83 (11.1%) for cell structure/motility, 70 (9.4%) for cell signaling/communication, 17 (2.3%) for cell division, and 163 (21.8%) matched to genes of unknown functions. The list of host-defense genes included many genes with known and important roles in innate defense such as lectins, defensins, proteases, protease inhibitors, heat shock proteins, antioxidants, and Toll-like receptors. The study provides a significant number of ESTs for gene discovery and candidate genes for studying host defense in scallops and other molluscs.