改进的小波域医学图像序列的运动估计

医学图像序列压缩是远程医疗系统中的重要技术，而运动估计在视频序列压缩中起着关键作用。我们提出了一种改进的正方形-菱形搜索算法来实现医学图像序列的运动估计。这种改进的正方形-菱形算法减少了搜索点数。我们将其应用于小波域的医学图像序列的运动估计，并对数字减影血管造影图像序列（DSA）进行实验。结果表明，改进后的小波域正方形-菱形算法较其他算法精度高。     

Worry研究的新进展

Worry具有难以控制性和持续性的特点。其机制既有自动的加工过程也包含控制的加工过程。高Worry倾向者对否定性信息具有过度的选择性注意,其结果是限制了问题的解决、增强了Worry的唯以控制感;高Worry倾向者确定问题解决策略的持续时间校长,从而造一步增强了解决问题的动机．长时间的持续思考增强了Worry的难以控制感。     

NIH 3T3细胞转化前后细胞骨架及细胞表面纤维粘连蛋白的免疫荧光观察

本实验用抗纤维粘连蛋白(FN)亲和层析纯抗体和抗管蛋白抗体及鬼笔环肽,以免疫荧光组织化学方法,对NIH3T3细胞转染人肺腺癌细胞系AGZY基因组DNA前后细胞表面FN及细胞内骨架系统进行染色观察。结果表明,细胞在发生转化后,微丝及微管均表现出明显受损,细胞骨架结构不清,呈现为弥散样荧光;细胞表面FN大量减少,仅及正常NIH3T3细胞的1/9,其分布也由细丝形成的网状,变成斑点或斑块状。这一结果进一步证实,细胞恶变是涉及到细胞骨架系统及膜表面糖蛋白变化的复杂过程,并预示这些变化可能就是导致细胞形态发生变化、细胞失去正常生长调控的原因之一。     

Task-dependent mixtures of coordinate systems in visuomotor transformations

In two experiments the involvement of relative and fixed coordinate systems in visuomotor transformations was examined. The experimental task required the successive performance of two movements in each trial, which had to “correspond” to different visual stimuli. One kind of visual display indicated target positions by way of different horizontal positions of a vertical line on a monitor (position mode), while the other indicated movement amplitudes by way of different lengths of a horizontal line (amplitude mode). Formal analysis of variances and covariances of successive individual movements led to the conclusion that in the position mode visuomotor transformations were based on a mixture of relative and fixed coordinate systems, while in the amplitude mode only a relative coordinate system was involved. Thus, visuomotor transformations can be characterized as mixtures of different coordinate systems, and their respective weights in the mixtures are task-dependent. Received: 18 March 1997 / Accepted: 25 September 1997     

Sequence analysis of the gene coding for glyceraldehyde-3-phosphate dehydrogenase (gpd) of Podospora anserina: use of homologous regulatory sequences to improve transformation efficiency

Summary The glyceraldehyde-3-phosphate dehydrogenase (gpd) gene of Podospora anserina has been isolated from a genomic library by heterologous hybridization with the corresponding gene of Curvularia lunata. The coding region consists of 1014 nucleotides and is interrupted by a single intron. The amino-acid sequence encoded by the gpd gene shows a high degree of sequence identity with the corresponding gene products of various fungi. Multiple alignments of all fungal GPD sequences so far available resulted in the construction of a phylogenetic tree. The evolutionary relationships of the various fungi belonging to different taxa will be discussed on the basis of these data. Sequence analysis of 1.9 kbp of the 5 non-coding region revealed the presence of typical fungal promoter elements. Utilizing different parts of the 5 regulatory sequence of the Podospora gpd gene, expression vectors containing a dominant selectable marker gene (hygromycin B phosphotransferase) have been constructed for the transformation of P. anserina protoplasts. The use of these homologous gpd regulatory sequences resulted in a significant increase in transformation efficiencies compared to those obtained with vectors in which the selectable marker gene is under the control of the corresponding heterologous promoter of Aspergillus nidulans.     

Effects of methylprednisolone on the neural conduction of the motor evoked potentials in spinal cord injured rats

Methylprednisolone(MP), a glucocorticoid steroid, has an anti-inflammatory action and seems to inhibit the formation of oxygen free radicals produced during lipid peroxidation in a spinal cord injury(SCI). However, the effects of MP on the functional recovery after a SCI is controversial. The present study was conducted to determine the effects of MP on the recovery of neural conduction following a SCI. A SCI was produced using the NYU spinal cord impactor. A behavioral test was conducted to measure neurological disorders, and motor evoked potentials (MEPs) were recorded. According to the behavioral test, using BBB locomotor scaling, MP-treated animals showed improved functional recoveries when compared to saline-treated animals. MEP latencies in the MP-treated group were shortened when compared to those in the control group. Peak amplitudes of MEPs were larger in the MP-treated group than those in the control group. The thresholds of MEPs tended to be lower in the MP-treated group than those in the control group. These results suggest that MP may improve functional recovery after a SCI.     

眼底图像畸变的校正及多幅图像的特征点拼接算法

对于眼底图像 ,由于不在正视点取像造成的几何畸变和由于荧光素从血管壁渗漏等造成的灰度畸变 ,几乎是不可避免的。为临床诊断提供丰富信息的需要出发 ,进行多幅眼底图像的拼接是必要的。本文为此提出了几个新的处理方法 ,如基于大窗口的滤波灰度校正方法、基于透视投影原理的几何校正方法与基于小波子空间上的拼接算法 ,均具有效果好和耗时少的优点。     

Studies on homologous recombination in the green alga Chlamydomonas reinhardtii

The introduction of exogenous DNA into the nuclear genome of Chlamydomonas reinhardtii occurs predominantly via non-homologous (illegitimate) recombination and results in integration at apparently-random loci. Using truncated and modified versions of the C. reinhardtii ARG7 gene in a series of transformation experiments, we demonstrate that homologous recombination between introduced DNA molecules occurs readily in C. reinhardtii, requires a region of homology of no more than 230 bp, and gives rise to intact copies of ARG7 in the nuclear genome. Evidence is presented for homologous recombination between introduced ARG7 DNA and the resident copy of the gene, and for the de-novo synthesis of the ARG7 sequence during transformation.     

人肿瘤细胞TH2类细胞因子的逆转与NK抗性变化的研究

目的研究促使人肿瘤细胞中ＴＨ２类细胞因子表达向ＴＨ０型的逆转及逆转后的肿瘤细胞对ＮＫ抗性的变化。方法首先用ＭＴＴ方法对悬浮培养的肿瘤细胞株ＤＢ大淋巴细胞瘤、Ｋａｒｐａｓ淋巴瘤、Ｍｉｃｈａｅｌ淋巴瘤、Ｒａｊｉ、ＨＬ６０和Ｋ５６２进行了ＮＫ杀伤敏感性的筛选。选择ＮＫ不敏感的Ｋａｒｐａｓ淋巴瘤和ＨＬ６０，用ｒｈＩＦＮγ、ｒｈＩＬ－１２和抗ＩＬ－１０ＭｃＡｂ经不同组合对其进行由ＴＨ２类细胞因子表达向ＴＨ１类细胞因子表达的促逆转研究，并观察促逆转后的肿瘤细胞对ＮＫ抗性的变化。结果ＲＴ－ＰＣＲ结果表明，经上述不同细胞因子组合诱导后，Ｋａｒｐａｓ淋巴瘤细胞均从表达ＴＨ２类细胞因子为主向ＴＨ０型逆转，并且各组逆转后的肿瘤细胞对ＮＫ的抗性均有不同程度的减弱。结论ＴＨ１类细胞因子（如ＩＦＮγ）、ＴＨ２类细胞因子拮抗剂（如ＩＬ－１０单抗）和ＩＬ－１２不同程度地促进肿瘤细胞表达的细胞因子由ＴＨ２型向ＴＨ０／ＴＨ１型逆转。促逆转后可以改善肿瘤细胞对机体杀伤作用的敏感性，提高抗肿瘤免疫能力     

Cloning of the nitrate reductase gene of Stagonospora (Septoria) nodorum and its use as a selectable marker for targeted transformation

The nitrate reductase gene (NIA1) of the phytopathogenic fungus Stagonospora (Septoria) nodorum has been cloned from a cosmid library by homologous hybridisation with a PCR-generated probe. A 6.7-kb fragment carrying the NIA1 gene was subcloned and partially characterised by restriction mapping. Sequencing of the gene indicated a high degree of homology, both at the nucleotide and amino-acid levels, with nitrate reductase genes of other filamentous fungi. Furthermore, consensus regulatory signals thought to be involved in the control of nitrogen metabolism are present in the 5′ flanking region. The cloned NIA1 gene has been used to develop a gene-transfer system based on nitrate assimilation. Stable nia1 mutants of S. nodorum defective in nitrate reductase were isolated by virtue of their resistance to chlorate. These were transformed back to nitrate utilisation with the wild-type S. nodorum NIA1 gene. Southern analyses revealed that transformation occurred as a result of the integration of transforming DNA into the fungal genome; in all cases examined, integration was targeted to the homologous sequence. Received: 30 March / 9 June 1998