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991.
HI Huppertz D Busch H Schmidt S Aleksic H Karch 《Canadian Metallurgical Quarterly》1996,128(3):341-346
The aim of this study was to evaluate the way in which short-term protection declines and is eventually lost in preconditioning and to determine the efficacy of a second preconditioning at various reperfusion intervals. Male rabbits were divided into six groups. Forty-five minutes (sustained) ischemia followed by 120 minutes reperfusion was applied 60, 65, 70, 75, and 80 minutes after a 5 minute preconditioning (groups A, B, C, D, and E) and in a control group (F) after no preconditioning. The infarct to risk ratio (I/R) was 38.3 +/- 3.5% in group A, 46.0 +/- 7.8% in B, 61.6 +/- 9.7% in C, 68.1 +/- 4.2% in D, 64.5 +/- 7.8% in E, and 61.0 +/- 7.7% in F. Group A had a smaller I/R compared with groups C, D, E, and F (p < 0.05). In another series, groups G, H, and I were exposed to two 5-minute preconditioning stimuli, separated, respectively, by 45, 60, and 75 minutes of reperfusion; 10 minutes after the last preconditioning, the animals were exposed to 45-minutes ischemia and 120 minutes reperfusion. Groups A and D (with the smaller and higher I/R ratio) were also incorporated into this protocol in order to compare the effect of the additional preconditioning with the single one. The I/R ratio was 25.4 +/- 8.5% in group G, 22.8 +/- 7.0% in group H, and 14.7 +/- 4.0% in group I (p = NS). Group D showed a higher I/R compared with groups G, A, and H (p < 0.01), and group I had a smaller I/R compared with groups A (p < 0.01) and D (p < 0.001). Cardioprotection after a first preconditioning declines gradually and is eventually lost. An additional preconditioning is always effective, and the longer the interval from the first preconditioning, the more potent is the effect. 相似文献
992.
The program HBexplore is a new tool for identifying and analysing H-bonding patterns in biological macromolecules. It selects all potential H-bonds according to geometrical criteria. The H-bond table can then be subjected to further automatic or interactive analysis tools. These tools include the calculation of mean values and distributions of geometrical H-bond parameters for parts of a single structure, for complete single structures and for structure sets, the classification of each H-bond according to the participation of backbone, side chain or base, ligand and water parts of nucleic acids or proteins, identification of Watson-Crick nucleotide pairs and of H-bonded pairs of equal nucleotides, the calculation of the mean number of H-bonds per residue, and of the fraction of potential donor and acceptor atoms involved in H-bonds. HBexplore further generates automatically a H-bond residue interaction table. This table lists for all residues of the structure the other residues, ligands or water molecules directly connected via a H-bond. By means of a binary tree search algorithm, this table is then converted into a H-bond cluster table. Clusters are understood here as an uninterrupted network of H-bonded residues. For nucleic acids, secondary structures and tertiary interactions are automatically derived from the H-bonding pattern. HBexplore is applied to two example RNA structures: a pseudoknot and a hairpin. It provides a comprehensive listing of individual H-bonds and statistical information for larger structure sets. In addition, it can identify interesting new H-bond motifs. One example is a pentanucleotide base-base H-bond interaction motif in the RNA pseudoknot. HBexplore is intended to contribute both to the elucidation of general principles of the architecture of biological macromolecules, and to the prediction and refinement of single structures. 相似文献
993.
V. A. Budarin 《Journal of Engineering Physics and Thermophysics》1995,68(2):182-185
The scheme of an experiment and certain results of the interaction of a free air vortex tube with a surface are considered. A solution of a differential equation for a plane cross section of a quasisolid tubular vortex core whose density varies according to a polytrope law is analyzed.Odessa Polytechnic University. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 2, pp. 212–216, March–April, 1995. 相似文献
994.
A. E. Bohe J. J. Andrade Gamboa E. M. Lopasso D. M. Pasquevich 《Journal of Materials Science》1996,31(13):3469-3474
A chlorination process for recovering Zr from zircaloy scrap has been studied. Zircaloy chlorination was possible at temperatures as low as 220 °C. The scale microstructure and its effect on the zircaloy reactivity was analysed using Thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS) and scanning electron microscopy (SEM) techniques. A solid-solid phase transformation took place into the oxide scale during the zircaloy chlorination. Zirconium, as ZrCl4(g), was separated from the oxide scale and chlorides of Cr and Fe. The effect of the reaction temperature was also analysed. 相似文献
995.
V. P. Naumenko 《Strength of Materials》1996,28(1):10-18
The adoption of unified fracture mechanics terminology (UFMT) will promote efficient communication between specialists in different fields of fracture research, harmonization of national and international standards relating to fracture mechanics, and last but not least improvement of the existing methodology for teaching and education in fatigue and fracture. In this paper the definitions of some basic and related terms included in different standards on fracture mechanics terminology are confronted with one another. Alternative definitions of the same terms are offered. By this strategy the author tries to show that the definitions of basic and related terms appropriate for the UFMT should emerge as a consequence of harmonizing a crack model with an actual crack and then both taken together with a fracture model, laboratory test methods, and failure assessment codes.Published in Problemy Prochonsti, No. 1, pp. 17–29, January, 1996.This paper is published as a matter of discussion. 相似文献
996.
R.M. Scanlan W.A. Barletta D. Dell'Orco A.D. McInturff A. Asner E.W. Collings P.F. Dahl H. Desportes A. Devred R. Garre E. Gregory W. Hassenzahl M. Lamm D. Larbalestier D. Leroy P. McIntyre J. Miller T. Shintomi H. ten Kate S. Wipf 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1996,380(3):544-554
997.
Design-quality metrics that are being developed for predicting the potential quality and complexity of the system being developed are discussed. The goal of the metrics is to provide timely design information that can guide a developer in producing a higher quality product. The metrics were tested on projects developed in a university setting with client partners in industry. To further validate the metrics, they were applied to professionally developed systems to test their predictive qualities. The results of applying two design metrics and a composite metric to data from a large-scale industrial project are presented 相似文献
998.
999.
G Makrydimas D Lolis I Georgiou C Skendou KH Nicolaides 《Canadian Metallurgical Quarterly》1997,6(6):314-316
For psychological reasons, coelocentesis was performed in 20 women prior to termination of pregnancy, at 6-11 weeks of gestation. The fetal heart rate (FHR) was measured immediately before the procedure and at 1, 5, and 10 min afterward. There was no significant difference between FHR before coelocentesis compared to the values at 1 min (mean = 158, range 114-178; z = -0.629, P = 0.529), 5 min (mean = 160, range 121-179; z = -0.191, P = 0.848), or 10 min (mean 159, range 117-183; z = -0.214, P = 0.83) after the procedure. These findings suggest that coelocentesis does not have a major effect on the fetal cardiovascular system. 相似文献
1000.