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排序方式: 共有2533条查询结果,搜索用时 15 毫秒
61.
CW van Haselen PV Diederen J Toonstra SC van der Putte LH Rademakers JA Faber WA van Vloten 《Canadian Metallurgical Quarterly》1998,290(11):583-590
Small-cell variants of Sézary syndrome and mycosis fungoides (MF) have been described. However, in these studies the nuclear area of the small-cell variant of MF (SC-MF) as compared to histological classical MF (CL-MF) was not characterized objectively by quantitative electron microscopy. In a 14-year follow-up period, of a total of 76 patch/plaque stage MF patients seen in the Department of Dermatology of the University Hospital Utrecht, 14 (18%) had an infiltrate composed of atypical lymphocytes characterized by a distinctly smaller cell diameter and smaller, hyperchromatic, deeply indented nuclei as compared to the usual cell type of MF. The aim of the investigation was to confirm this observation objectively using quantitative electron microscopy (morphometry) and to define SC-MF as compared to CL-MF. The study was performed on the 14 patients with SC-MF, and 10 patients with clinical and histological CL-MF and 4 patients with chronic eczema. Electron micrographs of sections obtained from each biopsy were analysed by computer to produce the following data: a nuclear contour index (NCI), the mean nuclear area (MNA), the mean nuclear area of the cells above the 75th percentile (P75NA) and the percentage of cells larger than 30 microm2. The values of MNA differed significantly between patients with SC-MF and those with CL-MF (17.6 vs 23.2 microm2; P = 0.02), as did the values of P75NA (20.7 vs 27.9 microm2; P = 0.01). The NCI of the SC-MF and CL-MF patients were similar. These results are consistent with our observations that SC-MF does indeed exist. 相似文献
62.
63.
SC Messer T Kempton VB Van Hasselt JA Null OG Bukstein 《Canadian Metallurgical Quarterly》1994,18(3):339-351
Despite a proliferation of recent research examining childhood and adolescent depression, the area still lags behind the adult depression field, particularly in the investigation of cognitive correlates of affective psychopathology. To advance cognitive research with youth, the Children's Negative Cognitive Error Questionnaire (CNCEQ) was developed to provide a measure of cognitive distortions or errors in children and adolescents. Yet, few studies have employed the CNCEQ and no evidence exists supporting the validity of its four component cognitive error scales. The purpose of the present study was to examine the construct validity of the CNCEQ and its constituent scales through the use of factor analysis and criterion-group comparisons. Groups of adolescent psychiatric inpatients, diagnosed as affective or disruptive disordered, completed the CNCEQ following admission. Results failed to support the implicit four-factor structure of the CNCEQ, instead suggesting the appropriateness of a single-factor solution labeled "negative thinking." Despite no diagnostic group differences on the CNCEQ total or other scale scores, affective disordered patients evinced more cognitive errors on the Overgeneralizing scale. Findings suggest that the CNCEQ in its current stage of development holds promise, yet requires refinement to produce a valid measure of cognitive functioning in youth. 相似文献
64.
BA Brown Y Li JC Brown CC Hardin JF Roberts SC Pelsue LD Shultz 《Canadian Metallurgical Quarterly》1998,37(46):16325-16337
A cell line that produces an autoantibody specific for DNA quadruplex structures has been isolated and cloned from a hybridoma library derived from 3-month-old nonimmunized autoimmune, immunodeficient "viable motheaten" mice. This antibody has been tested extensively in vitro and found to bind specifically to DNA quadruplex structures formed by two biologically relevant sequence motifs. Scatchard and nonlinear regression analyses using both one- and two-site models were used to derive association constants for the antibody-DNA binding reactions. In both cases, quadruplexes had higher association constants than triplex and duplex molecules. The anti-quadruplex antibody binds to the quadruplex formed by the promoter-region-derived oligonucleotide d(CGCG4GCG) (Ka = 3.3 x 10(6) M-1), and has enhanced affinity for telomere-derived quadruplexes formed by the oligonucleotides d(TG4) and d(T2G4T2G4T2G4T2G4) (Ka = 5.38 x 10(6) and 1.66 x 10(7) M-1, respectively). The antibody binds both types of quadruplexes but has preferential affinity for the parallel four-stranded structure. In vitro radioimmunofilter binding experiments demonstrated that purified anti-DNA quadruplex antibodies from anti-quadruplex antibody-producing tissue culture supernatants have at least 10-fold higher affinity for quadruplexes than for triplex and duplex DNA structures of similar base composition and length. The antibody binds intramolecular DNA triplexes formed by d(G4T3G4T3C4) and d(C4T3G4T3G4), and the duplex d(CGCGCGCGCG)2 with an affinities of 6. 76 x 10(5), 5.59 x 10(5), and 8.26 x 10(5) M-1, respectively. Competition experiments showed that melted quadruplexes are not effective competitors for antibody binding when compared to native structures, confirming that the quadruplex is bound structure-specifically. To our knowledge, this is the first immunological reagent known to specifically recognize quadruplex structures. Subsequent sequence analysis demonstrates homologies between the antibody complementarity determining regions and sequences from Myb family telomere binding proteins, which are hypothesized to control cell aging via telomeric DNA interactions. The presence of this antibody in the autoimmune repertoire suggests a possible linkage between autoimmunity, telomeric DNA binding proteins, and aging. 相似文献
65.
H Middleton 《Canadian Metallurgical Quarterly》1996,2(6):265-278
Self-report questionnaires have been used to compare panic patients' fears, anxious thoughts and behaviors with those of a group of controls. Individual items revealed significant differences between groups in all three areas: factor analysis revealed group differences in the pattern of intraquestionnaire associations between items. Correlational analysis of factor scores revealed significant group differences in the pattern of interquestionnaire associations. These findings only partly support a formulation of panic based upon "catastrophic interpretations." On the other hand, they do provide evidence of cognitive rigidity among panic patients which can be interpreted as evidence of impaired effortful processing when anxious. 相似文献
66.
The null controllable set of a system is the largest set of states that can be controlled to the origin. Control systems that have a region of attraction equal to the null controllable set are said to be maximally controllable closed-loop systems. In the case of open-loop unstable plants with amplitude constrained control it is well known that the null controllable set does not cover the entire state-space. Further the combination of input constraints and unstable system dynamics results in a set of state constraints which we call implicit constraints. It is shown that the simple inclusion of implicit constraints in a controller formulation results in a controller that achieves maximal controllability for a class of open-loop unstable systems. 相似文献
67.
In this paper a new systematic switching control approach to adaptive stabilization of linear time-varying (LTV) discrete-time systems is presented. A feature of the localization based method is its high model falsification capability, which in the case of LTI systems is manifested as the rapid convergence of the switching controller. We believe that the proposed method may help pave the way for design of practical adaptive switching controllers applicable to a wide range of linear time-invariant and time-varying systems 相似文献
68.
Edge detection in a hexagonal-image processing framework 总被引:2,自引:0,他引:2
With processing power of computers and capabilities of graphics devices increasing rapidly, the time is ripe to reconsider using hexagonal sampling for computer vision in earnest. This paper reports on an investigation of edge detection in the context of hexagonally sampled images. It presents a complete framework for processing hexagonally sampled images which addresses four key aspects: conversion of square to hexagonally sampled images, storage, processing, and display of these images. Results from using edge detection on this framework show that (a) the computational requirement for processing a hexagonally sampled image is less than that for square sampled images, and (b) a better qualitative performance which is due to the compact and circular nature of the hexagonal lattice. This last point needs to be exploited in the development of edge detectors for hexagonally sampled images. 相似文献
69.
Analysis of the S-phase fractions (SPF) measured by in vitro thymidine labeling, morphological appearances, and estrogen receptor (ER) assays of primary invasive breast carcinomas demonstrated several interrelationships. Lobular, mucinous, tubular, and adenocystic carcinomas consistently had low SPF and were usually positive for ER. The same was true for the carcinomas of no special histologic type [the not otherwise specified (NOS) group of E. R. Fisher including "infiltrating ductal" and undifferentiated carcinomas] with minimal anaplasia. Medullary, atypical medullary, and morphologically unclassifiable carcinomas with marked nuclear anaplasia nearly always had high SPF and were usually negative for ER. High SPF was associated with advanced stages of carcinoma initially or with early recurrence following mastectomy. 相似文献
70.
Intravenous glucose tolerance test in middle-aged men with and without latent coronary heart disease
During a cardiovascular survey, aimed at detecting cases of latent coronary heart disease (CHD), glucose elimination was studied after i.v. loading in 1970 presumably healthy men aged 40-59 years. The aim was to throw light on the importance of deranged glucose tolerance for the development of CHD. Of the 1970 individuals, 1798 were defined as "normals", 33 had chronic, non-anginal chest pain, 34 had slight albeit typical angina pectoris. The remaining 105 had various symptoms/signs strongly suggestive of CHD, and underwent diagnostic coronary angiography (69 angiopositive, 36 angionegative). Plasma insulin was determined in relation to the test in 249 of the subjects. The following conclusions were reached: 1) Mean k-values were similar in all subgroups (p less than 0.10). 2) Low and borderline k-values were significantly more frequent in angiographed individuals compared with the group of normals (p less than 0.025). However, an almost identical frequency was seen in angiopositive and angionegative cases. 3) K-values did not change with age between 40 and 59 years. 4) K-values were unrelated to the severity of angiographic findings in individuals with proven CHD. 5) Significantly lower k-values were found in individuals with a positive diabetic heredity, and 6) in individuals with a high insulin response. 7) The i.v. glucose loading did not influence an exercise ECG recorded in relation to a near-maximal bicycle exercise test. 相似文献