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1.
Amplification of a 340 bp sequence of the 38 kDa protein gene of Mycobacterium tuberculosis by the polymerase chain reaction has been developed. The sensitivity of this PCR was shown to be 10 fg both by agarose gel electrophoresis and Southern blot hybridisation being equivalent to 2-3 organisms and highly specific to M. tuberculosis and excluding even M. tuberculosis H37Ra and Mycobacterium bovis BCG. Sputum samples from patients with pulmonary tuberculosis gave a positivity rate of 45%. PCR was also performed using pt8 and pt9 primers which amplified a 541 bp sequence of IS6110. 41% of the above samples gave positive amplification. Three samples that were positive for 38 kDa sequence were negative for IS6110. 相似文献
2.
AH Kolk LF Kox J van Leeuwen S Kuijper HM Jansen 《Canadian Metallurgical Quarterly》1998,11(6):1222-1226
This study examines the diagnostic utility of the polymerase chain reaction (PCR) in 156 patients (five human immunodeficiency virus (HIV) seropositive) suspected of extrapulmonary tuberculosis. The results of PCR in 226 samples from 11 different sites were compared with the results of microscopy and culture. Positive culture results were predicted in 86% of samples by PCR but in only 31% by microscopy. Specificity of PCR was 92%. In cases with culture-proven tuberculosis, PCR identified all 11 microscopy positive cases and 19 of 24 (79%) of the microscopy-negative cases. In four patients, PCR excluded the diagnosis of tuberculosis in microscopy-positive samples, which were later shown to contain mycobacteria other than Mycobacterium tuberculosis or laboratory contaminants. In 20 patients (microscopy, PCR and culture negative) a trial of antituberculous drugs was given, but patients showed no improvement and treatment was stopped. In 17 patients, all culture negative (in nine PCR was positive, three of whom also had positive microscopy) the diagnosis was probable tuberculosis based on clinical findings and response to treatment. This polymerase chain reaction has a much higher sensitivity than microscopy and can facilitate therapeutic decisions for those with suspected extrapulmonary tuberculosis. 相似文献
3.
Abstact The simulation of 3D fatigue crack growth is investigated and in combination with suitable experiments it is aimed to identify
a reliable crack growth criterion. To perform the crack growth simulation as effectively as possible the boundary element
method (BEM) in terms of the 3D Dual BEM is utilized. The relevant boundary integral equations are evaluated in the framework
of a collocation procedure. To compress the system matrix and to speed-up the solution procedure the adaptive cross approximation
(ACA) method is applied. It is an algebraic technique acting purely on the system matrix itself. The efficiency of this procedure
with respect to crack problems will be shown on both a standard fracture specimen and an industrial application. 相似文献
4.
MH Kolk M van der Graaf CT Fransen SS Wijmenga CW Pleij HA Heus CW Hilbers 《Canadian Metallurgical Quarterly》1998,17(24):7498-7504
The solution structure of an RNA-hairpin present in the pseudoknot, which is found at the 3'-terminus of turnip yellow mosaic virus genomic RNA, has been solved by nuclear magnetic resonance spectroscopy. The loop, which contains the sequence 5'-GGGUCA-3', was found to be highly structured and, contrary to expectations, does not attain its stability through GA or GC base pair formation but by triple interactions between the tilted adenosine and the minor groove sides of the first two guanosines. Interestingly, a very similar conformation was found for the cognate pseudoknot, implying that the 3'-hairpin is preformed for folding into a pseudoknotted structure. These findings suggest a mechanism of 'predetermined-fit' as a principle in RNA folding. 相似文献
5.
Health surveys, studies on physical symptom reporting, and medical registration of physical complaints find consistent sex differences in symptom reporting, with women having the higher rates. By and large, this female excess of physical symptoms is independent from the symptom measure, response format and time frame used, and the population under study. As most studies concern healthy individuals, the sex difference can not simply be attributed to a greater physical morbidity in women. In this paper we propose a number of explanations for this phenomenon, based on a biopsychosocial perspective on symptom perception. We discuss a symptom perception model that brings together factors and processes from the extant literature which are thought to affect symptom reporting, such as somatic information, selection of information through attention and distraction, attribution of somatic sensations, and the personality factors somatisation and negative affectivity. Finally, we discuss the explanations for sex differences in physical symptoms that arise from the model. 相似文献
6.
The first six years of the seventies have been a period of rapid developments in the field of rotating memory. Innovation has dominated the gamut of disk drive applications. For example, substantial inroads have been made by flexible disks into the low-entry-cost area where rotating memory was previously not competitive. Cartridge disk drives have gained dramatically in capacity and performance while prices have remained relatively steady. The announcement of the IBM 3340, Winchester, brought to the marketplace the concept of a pack with its own captive heads in order to obtain large capacity at modest cost by increased surface storage density. The IBM System 32 brought the concept of the "disk enclosure" which treats a substantial part of a disk system as a field replaceable component. Independent disk manufacturers have responded to the latter two IBM developments with their versions of modest-cost, high-capacity, replaceable media drives and with very low cost, fixed-disk systems. 相似文献
7.
G.J. Van Der Kolk A. Van Veen J.Th.M. De Hosson R.H.J. Fastenau 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1985,6(3):525-532
Trapping of He by vacancies and drainage of He from substitutional implants (Ag and Kr in W) to nearby vacancies are investigated using static lattice calculations. The calculations indicate that drainage of He will occur to vacancies within a radius of 2.5 lattice units from the implant. Furthermore the trapping probability of substitutional and interstitial random walkers on a bcc lattice by substitutional traps or vacancies is calculated. When implantation-produced vacancies are present in the vicinity of the observed trap a shielding effect occurs. Trapping constants are calculated with two random walk models for both the unshielded and the shielded defect. For the latter several configurations were taken. The results show that shielding of a defect by one vacancy at a distance of three lattice units leads already to a reduction of He trapping by that defect of 30% to 40%. 相似文献
8.
9.
David X. Kolk 《Energy Economics》1983,5(2):105-113
This paper presents a methodology for incorporating price-induced technological substitution into a regional input-output forecasting model. The model was used to determine the employment impacts of rapidly escalating energy costs on the Riverside-San Bernardino (California) SMSA. The results indicate that the substitution effect between energy and other goods was dominated by the income effect. A reallocation of consumer expenditures from labour intensive to energy intensive goods occured, resulting in a two-to threefold increase in the unemployment rate among low-skilled individuals. 相似文献
10.
Aguor EN Arslan F van de Kolk CW Nederhoff MG Doevendans PA van Echteld CJ Pasterkamp G Strijkers GJ 《Magma (New York, N.Y.)》2012,25(5):369-379