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41.
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Magnetization prepared segmented acquisition requires a view order that maximizes signal contrast during the acquisition of the central portion of k-space. Steady state free precession (SSFP) acquisition further requires a view order that minimizes changes in phase-encoding gradients from one repetition to the next in order to minimize eddy current artifacts. In this article, optimal view ordering schemes satisfying these two requirements are formulated and applied to inversion prepared 3D SSFP contrast-enhanced MR angiography (MRA). Experiments on phantoms and pigs demonstrated improved background suppression and reduced image artifacts. 相似文献
43.
C Schweitzer L T T Vu Y T Nguyen C Choné B Demoulin F Marchal 《The European respiratory journal》2006,28(1):89-95
The bronchomotor effects of a deep inhalation (DI) may provide relevant information about the mechanisms of exercise-induced airway obstruction in children and may be assessed by respiratory conductance (Grs) measured using the forced oscillation technique. The aims of the present study were to assess the effect of DI on Grs after exercise in relationship to the lung function response to exercise. Grs at 12 Hz using a head generator and spirometric data were measured in 62 children suspected of asthma before and 5 min after a 6-min free run. After exercise, Grs was significantly increased by DI in 38 subjects, who also showed larger Grs and forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) responses to exercise than the 24 nonresponders. Stepwise regression indicated significant correlation between the response of Grs to DI and both Grs and FEV1/FVC responses to exercise. The data are consistent with exercise-induced bronchoconstriction being reversed by deep inhalation. 相似文献
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Hung Anh Nguyen Herv Cheradame Ernest Marchal 《Macromolecular chemistry and physics.》1992,193(9):2495-2503
The 1,3-dipolar addition of 2-azido-2,4,4-trimethylpentane ( 1 ) to acetylene and ethylene derivatives such as phenylacetylene (2), acrylonitrile, diphenyl fumarate ( 4 ) and N,N′-methylenebis(1,4-phenylene)dimaleimide ( 8 ) leads to the corresponding triazole and triazoline derivatives. This study demonstrates that tertiary azides are able to react with dienophiles, and the application of this reaction for the synthesis of block copolymers was investigated with monoazido-telechelic poly(2-methylpropene) (PMP). It was shown that the azido group is stable under the severe conditions of the polycondensation reaction without decomposition (170°C, 24 h), and the monoadduct PMP- 8 is produced with acceptable yield. 相似文献
47.
Since the last two decades, rapid progress has been made in the field of cancer immunotherapy relevant to manipulation of adaptative cytotoxic T lymphocytes (CTLs) and innate immunity natural killer (NK) cells as well as antibodies. Many possibilities are now offered for therapeutic purposes contributing to better approaches in treatment of cancer. 相似文献
48.
Previous research has demonstrated that 2-item versions of subscales from the Chronic Pain Coping Inventory, Coping Strategy Questionnaire, and the Survey of Pain Attitudes appear adequately reliable and valid for use in studies with large sample sizes. It was suggested that use of the abbreviated scales might help to expand the testing and application of cognitive-behavioral models of pain to new settings and with new populations where assessment burden might be a key issue. This study explored the utility of these brief scales among veterans in a Veterans Affairs setting. Strong associations were found between the 2-item versions and their respective parent scales. In addition, the 2-item scales were found to be associated with other pain-related measures, supporting their predictive validity. The results of this study replicate previous findings and offer support for the use of the 2-item versions for both screening and research purposes in Veterans Affairs settings with a veteran population. PERSPECTIVE: This article presents the psychometric properties of brief versions of 3 commonly used pain coping and belief questionnaires in a unique population. These measures could be used clinically for initial screening purposes, as well as for treatment monitoring. 相似文献
49.
The ability of wound fluids to support events required for skeletal muscle regeneration was examined. Wound fluids were obtained from polyvinyl alcohol sponges 1, 3, 5, 10, and 15 days after implantation. Neonatal rat L8 myoblasts were used to test the ability of early wound fluids to promote myoblast proliferation and late wound fluids to promote myoblast differentiation-two characteristics deemed critical for effective skeletal muscle regeneration. Early wound fluids (1- and 3-day) stimulated DNA replication by myoblasts, as judged by tritiated thymidine uptake, up to ninefold (p < 0.05). Later wound fluids (5-, 10-, and 15-day) displayed decreasing ability to stimulate proliferation, with 15-day wound fluid failing to significantly stimulate proliferation. In contrast, myoblast differentiation, as judged by myotube fusion and creatine kinase activity, was progressively reduced by wound fluids of increasing age. In fact, late wound fluids (5, 10, and 15 days) reduced myotube fusion by 88% to 100% and depressed creatine kinase activity by 60% to 75% (p < 0.05). Thus, wound fluids from a repair environment appear to support myoblast proliferation early but suppress myoblast differentiation later. These characteristics suggest that the wound repair environment cannot fully support skeletal muscle regeneration. 相似文献
50.
Phuc Nguyen 《Child & youth care forum》1992,21(2):91-104
A Vietnamese social work and youth studies student describes her experiences and her feelings as a volunteer intern in an urban shelter program for children and youth in the United States. 相似文献