排序方式: 共有55条查询结果,搜索用时 31 毫秒
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Gilkes ML Albergo S Bieser F Brady FP Caccia Z Cebra DA Chacon AD Chance JL Choi Y Costa S Elliott JB Hauger JA Hirsch AS Hjort EL Insolia A Justice M Keane D Kintner JC Lindenstruth V Lisa MA Lynen U Matis HS McMahan M McParland C Müller WF Olson DL Partlan MD Porile NT Potenza R Rai G Rasmussen J Ritter HG Romanski J Romero JL Russo GV Sann H Scharenberg R Scott A Shao Y Srivastava BK Symons TJ Tincknell M Tuvé C Wang S Warren P Wieman HH Wolf K 《Physical review letters》1994,73(12):1590-1593
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Carl E. Wieman 《Hyperfine Interactions》1993,81(1-4):27-34
Parity nonconservation has now been measured in atomic cesium with a fractional uncertainty of 2%. This was done by observing the 6S–7S laser excited transition rate in a handed apparatus. When combined with recent precise calculations of the cesium atomic structure, this provides an important test of the Standard Model. Efforts are under way to achieve a more sensitive test by measuring parity nonconservation in a series of radioactive cesium isotopes which have been trapped using laser light. 相似文献
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We present techniques for the most efficient capture of atoms in a modified vaporcell magneto-optical trap. We explain how changing the size and power of the trapping beams affects the capture rate of the trap. We calculate the requirement of wall coatings designed to minimize the interaction of an alkali vapor with the wall and explain how this affects trapping efficiency. Finally, we present measurements of the performance of a Dryfilm coated cell. 相似文献
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The Effects of Thrombocytopenia on Vessel Stasis and Macromolecular Leakage after Photodynamic Therapy Using Photofrin 总被引:8,自引:0,他引:8
Victor H. Fingar T. Jeffery Wieman Pamela S. Haydon 《Photochemistry and photobiology》1997,66(4):513-517
Abstract— Several studies have reported thrombus formation and/or the release of specific vasoactive eicosanoids, suggesting that platelet activation or damage after photodynamic therapy (PDT) may contribute to blood flow stasis. The role of circulating platelets on blood flow stasis and vascular leakage of macromolecules during and after PDT was assessed in an intravital animal model. Sprague-Daw-ley rats bearing chondrosarcoma on the right hind limb were injected intravenously (i.v.) with 25 mg/kg Photofrin 24 h before light treatment of 135 J/cm2 at 630 nm. Thrombocytopenia was induced in animals by administration of 3.75 mg/kg of rabbit anti-rat platelet antibody i.v. 30 min before the initiation of the light treatment. This regimen reduced circulating platelet levels from 300000/mm3 to 20000/mm3 . Reductions in the luminal diameter of the microvasculature in normal muscle and tumor were observed in control animals given Photofrin and light. Venule leakage of macromolecules was noted shortly after the start of light treatment and continued throughout the period of observation. Animals made thrombocytopenic showed none of these changes after PDT in either normal tissues or tumor. The lack of vessel response correlated with the absence of thromboxane release in blood during PDT. These data suggest that platelets and eicosanoid release are necessary for vessel constriction and blood flow stasis after PDT using Photofrin. 相似文献
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Analysis of pulmonary microvasculature changes after photodynamic therapy delivered to distant sites
ten Tije AJ Wieman TJ Taber SW Tseng MT Cerrito PB Jansen JM Guo HH Fingar VH 《Photochemistry and photobiology》1999,69(4):494-499
Photodynamic therapy (PDT) can exert local damage by direct tumor cytotoxicity, by disruption of the microvasculature or by a combination of these effects. Although systemic effects after PDT of small tissue areas (< 1% total body surface area) are unlikely, treatment of larger areas may result in an accumulated effect leading to toxicity. Several investigators have described animal death after high dose PDT to tumors on the hind limb of animals and hypothesized that a toxic shock syndrome caused by vasoactive agents released after PDT is responsible. Because one of the most vulnerable organs to toxic shock injury is the lung, we studied the systemic effects of local PDT to this organ by intravital microscopy using a pulmonary window chamber. The PDT treatment conditions (25 mg/kg Photofrin, 24 h, 150 J/cm2 630 nm, maximum area 6.28 cm2) were chosen that produce systemic toxicity and lethality in rats. Adhesion of leukocytes in the lung was monitored in vivo using anti-CD-13-labeled microspheres. The progression of pulmonary edema was assessed by monitoring the leakage of rhodamine-labeled albumin and by wet-to-dry lung weight ratios. Although an increased leukocyte adherence was observed and a significant number of animals died after the extensive PDT treatment, no biologically significant lung edema could be demonstrated. These data indicate that lung edema and acute respiratory distress syndrome is not the cause of death in these animals and that the toxicity is related to other mechanisms including circulatory shock after extensive muscle damage. 相似文献
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We report on the observation of controllable phase separation in a dual-species Bose-Einstein condensate with 85Rb and 87Rb. Interatomic interactions between the different components determine the miscibility of the two quantum fluids. In our experiments, we can clearly observe immiscible behavior via a dramatic spatial separation of the two species. Furthermore, a magnetic-field Feshbach resonance is used to change them between miscible and immiscible by tuning the 85Rb scattering length. The spatial density pattern of the immiscible quantum fluids exhibits complex alternating-domain structures that are uncharacteristic of its stationary ground state. 相似文献
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