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31.
Müller T Ball T Kristeva-Feige R Mergner T Timmer J 《Medical & biological engineering & computing》2000,38(1):62-67
The aim is to describe a general approach to determining important electrode positions when measured electro-encephalogram
signals are used for classification. The approach is exemplified in the frame of the brain-computer interface, which crucially
depends on the classification of different brain states. To classify two brain states, e.g. planning of movement of right
and left index fingers, three different approaches are compared: classification using a physiologically motivated set of four
electrodes, a set determined by principal component analysis and electrodes determined by spatial pattern analysis. Spatial
pattern analysis enhances the classification rate significantly from 61.3±1.8% (with four electrodes) to 71.8±1.4%, whereas
the classification rate using principal component analysis is significantly lower (65.2±1.4%). Most of the 61 electrodes used
have no influence on the classification rate, so that, in future experiments, the setup can be simplified drastically to six
to eight electrodes without loss of information. 相似文献
32.
目的:获得足够量的分泌片(SC)及其相应的抗血清,用于研究SC的功能与SC在人和某些物种黏膜组织内的分布。方法:在已有的凝胶过滤和离子交换层析的基础上,进一步通过亲和层析和凝胶过滤分离纯化人的SC并进行相应的鉴定。用免疫组织化学技术检测了SC在部分小鼠组织中的表达。结果:获得了免疫纯的SC,并制备了相应的兔抗人SC的免疫血清;免疫组化显示,SC在小鼠小肠和子宫内膜处有表达。结论:利用改进的方法可以获得免疫纯的SC,进一步证实人和小鼠SC之间的交叉反应性。 相似文献
33.
The classical enzyme and protein markers ACP1 and GC have gained new importance because of the biological functions of their gene products. ACP1 encodes a low molecular weight enzyme which is now recognized as a phosphotyrosine phosphatase with a role in the regulation of signal transduction pathways, and GC‐globulin acts both as a transporter of vitamin D and as a plasma actin scavenger and plays a role in macrophage activation. These two polymorphisms were phenotyped for decades on the basis of electrophoretic isozyme or protein patterns; the gene structures are now known. Nucleotide substitutions determining the common alleles are close enough at each locus to be contained in one short PCR product. We have developed a simple, rapid and reliable multiplex method based on PCR and SSCP which allows the simultaneous determination of the common ACP1 and GC genotypes. 相似文献
34.
Atsushi Sasaki Tsutomu Daa Kenji Kashima Shigeo Yokoyama Iwao Nakayama Shiro Noguchi 《Pathology international》1996,46(12):939-946
Forty-four thyroid carcinomas with an Insular component (JC) were reviewed from 2457 tumors diagnosed as papillary (PC) or follicular carcinoma (FC). These tumors were classified as FC with an IC (FCIC; 30 cases) and PC with an IC (PCIC; 14 cases). Both tumors were composed of solid cell nests in some areas and had a tendency toward a characteristic nuclear size: FCIC had a small nucleus and PCIC contained a nucleus of an Intermediate type or a large nucleus similar to that of PC, although there were numerous tumors with an exceptional nuclear size. The mean age and tumor diameter were the highest and largest in FCIC, respectively, followed by PCIC. Among the 44 cases, 17 patients died of the disease, two were alive with the disease and 18 were alive without the disease. From 13 clinicopathological factors, the presence of an IC, age, non-encapsulation, tumor size, vascular invasion and necrosis were found to be independent variables for actual prognosis of FC and PC based on univariate analysis followed by multtvariate analysis. The results of the present study indicate that the presence of an IC is an independent aggressive prognostic factor for patients with PC and FC. 相似文献
35.
36.
Inaccurate reporting of the absence of an endocervical (EC) component on Pap smears often results in slide rescreens, amended reports, clinician dissatisfaction, and sometimes unnecessary repeat smears. Therefore, the accuracy of reporting EC component adequacy was selected as a quality indicator for the laboratory continuous quality improvement program (CQI). The process consisted of problem identification, analysis of the situation, collection of data, implementation of solutions, and evaluation of results. The objective of the study was to determine if the accuracy of reporting EC component adequacy on Pap smears improved after application of such a program. During the first phase, 150 Pap smears originally reported with the absence of an adequate EC component and 150 smears reported with the presence of an adequate EC component were rescreened to measure the baseline accuracy of EC component adequacy reporting. The improvement process was then implemented. A cause-and-effect diagram was developed and root cause was determined. A presentation was then made to the cytology staff. Criteria for EC component adequacy were reviewed, examples were shown, and standardized marking of EC component was implemented. Following improvement actions, a second audit of 150 Pap smears reported with the absence of an adequate EC component as well as 150 smears reported with the presence of an adequate EC component was undertaken to measure change in performance in assessing EC component adequacy. For the baseline rescreening, before initiation of the CQI program, 98% accuracy was achieved with smears that were reported as adequate for EC component present. However, the accuracy with smears reported as absence of an adequate EC component was only 71%, i.e., an adequate EC component was identified in almost 1/3 of these cases on rescreen. After the implementation of improvement actions, the accuracy with smears reported with the presence of EC component remained high (98%) and the accuracy of reporting the absence of EC component was 90%. The difference of the latter before and after the implementation was statistically significant (P = 0.015, z-test). The accuracy of reporting EC component adequacy increased following the CQI process. Using reporting EC component adequacy as an example, we demonstrate that by treating clinical problems as quality control issues and applying basic quality improvement tools, a positive outcome can be effected. 相似文献
37.
Muscle synergies involved in shifting the center of pressure while making a first step 总被引:4,自引:0,他引:4
Wang Y Zatsiorsky VM Latash ML 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2005,167(2):196-210
We used the framework of the uncontrolled manifold (UCM) hypothesis to analyze multi-muscle synergies involved in making a
step by a standing person. We hypothesized that leg and trunk muscles are organized into stable groups (muscle modes, M-modes)
related to shifts of the center of pressure (COP) in the anterior-posterior and medio-lateral directions. Another hypothesis
was that the magnitudes of the modes co-vary across repetitive trials to stabilize a certain magnitude of the COP shift in
both directions. M-modes were defined using principal component analysis applied to indices of changes in the electromyographic
(EMG) activity prior to releasing variable loads that were held by the subject using a pulley system. For the task of releasing
the load behind the body three M-modes associated with a backward COP shift were defined. Four M-modes were defined for the
task of releasing the load at the body side associated with a lateral COP shift. Multiple regression analysis was used to
relate changes in the M-mode magnitudes to COP shifts. EMG changes prior to making a step were quantified over five 100 ms
time windows before the lift-off of the stepping leg. Two components of the variance in the M-mode space computed across repetitions
of a stepping task were quantified—a component that did not affect the average COP shift in a particular direction (variance
within the UCM, V
UCM), and a component that affected the COP shift (variance orthogonal to the UCM, V
ORT). V
UCM was significantly higher than V
ORT for both directions of the COP shifts. This relation was observed for the M-modes in the stepping leg as well as in the support
leg. The stepping leg showed a different time evolution of the ratio V
UCM/V
ORT such that the difference between the two variance components disappeared closer to the time of the lift-off. The findings
corroborate both main hypotheses. The study supports a view that control of whole-body actions involves grouping the muscles,
using fewer elemental variables to scale the muscle activity, and forming synergies in the space of the elemental variables
that stabilize time profiles of important performance variables. 相似文献
38.
Mutual inhibition of the binding of Clq and protein A to rabbit IgG immune complexes 总被引:1,自引:0,他引:1
A complex of rabbit IgG antibody with horseradish peroxidase covalently linked to Sepharose 4B was used as an insoluble immune complex for studying the binding of complement factor C1q protein A from Staphylococcus aureus, and its IgG-binding fragments AB and B, to rabbit IgG. It was shown that protein A (mol. wt approx. 42,000) and fragments AB and B (mol. wts approx. 14,000 and 7000, respectively) inhibited the binding of C1q to insoluble immune complex at 4 degrees C. However, at 37 degrees C fragment B did not inhibit this binding. On the other hand, C1q, when bound to an insoluble immune complex, almost completely blocked the binding of protein A and fragment B at both temps. The higher affinity of C1q for its CH2-binding site than of fragment B for its CH2-binding site may explain the displacement of the latter from the CH2 domain. The mutual inhibition of the binding of C1q and protein A (and its smaller fragments) indicates that the binding sites for C1q and protein A are closely located in the CH2 domain. 相似文献
39.
Principal components analysis of evoked potentials differing between groups presents an interpretive problem, particularly in psychiatric research. Two sets of principal components and associated factor scores may appear to differ. The issue is to determine the extent to which visually differing principal components and resultant factor scores span the same factor space. Sets of evoked potentials from controls and from schizophrenics were each subjected to principal components analysis, from which factor score coefficients were computed for all subjects. This allowed determination of the extent to which (1) the two sets of basis waves were similar and (2) the factor scores resulting from the set of basis waves derived from principal components analysis of the control subjects' evoked potential data adequately represented those of the schizophrenics and vice-versa. Canonical correlation analyses indicated substantial similarities between the principal component structures (sets of basis waves). Multiple correlational analyses confirmed that the basis waves from either group spanned the other group's factor space. Factor scores from either set of basis waves were highly correlated. These results suggest that principal component structures derived from evoked potentials of a control group may be used in computing evoked potential factor scores of psychiatrically diverse populations even though the average evoked potentials of the groups may differ in several ways. 相似文献
40.
目的 检测血清淀粉样P成分(SAP)与不同DNA的结合活性并研究SAP与DNA的结合是否有利于此类抗原的清除,探讨它在SLE发生发展中的作用及意义。方法 用亲和层析和凝胶过滤方法自小鼠和人血清中纯化SAP,分别提取来自细菌、质粒、酵母、小鼠淋巴细胞等不同DNA,用DOT-EIA方法检测SAP与它们的结合活性,用巨噬细胞吞噬实验观察SAP与DNA结合后对DNA清除的影响。结果 人和小鼠SAP均与细菌DNA结合最强,其次为质粒、酵母DNA,与淋巴细胞DNA和小牛胸腺DNA的结合较弱,与单链λDNA结合最弱;与来源于活化状态小鼠淋巴细胞DNA的结合力高于非活化状态;SAP与活化淋巴细胞DNA结合后可促进巨噬细胞对DNA的吞噬。结论 SAP与不同DNA结合活性各异。 相似文献