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41.
K J Falke R D Hill J Qvist R C Schneider M Guppy G C Liggins P W Hochachka R E Elliott W M Zapol 《Science (New York, N.Y.)》1985,229(4713):556-558
Arterial blood nitrogen tensions of free-diving Weddell seals (Leptonychotes weddelli) were measured by attaching a microprocessor-controlled blood pump and drawing samples at depth to determine how these marine mammals dive to great depths and ascend rapidly without developing decompression sickness. Forty-seven samples of arterial blood were obtained from four Weddell seals during free dives lasting up to 23 minutes to depths of 230 meters beneath the sea ice of McMurdo Sound, Antarctica. Peak arterial blood nitrogen tensions of between 2000 and 2500 millimeters of mercury were recorded at depths of 40 to 80 meters during descent, indicating that the seal's lung collapses by 25 to 50 meters. Then arterial blood nitrogen tensions slowly decreased to about 1500 millimeters of mercury at the surface. In a single dive, alveolar collapse and redistribution of blood nitrogen allow the seal to avoid nitrogen narcosis and decompression sickness. 相似文献
42.
Polymerase chain reaction with single-sided specificity: analysis of T cell receptor delta chain 总被引:104,自引:0,他引:104
In the polymerase chain reaction (PCR), two specific oligonucleotide primers are used to amplify the sequences between them. However, this technique is not suitable for amplifying genes that encode molecules where the 5' portion of the sequences of interest is not known, such as the T cell receptor (TCR) or immunoglobulins. Because of this limitation, a novel technique, anchored polymerase chain reaction (A-PCR), was devised that requires sequence specificity only on the 3' end of the target fragment. It was used to analyze TCR delta chain mRNA's from human peripheral blood gamma delta T cells. Most of these cells had a V delta gene segment not previously described (V delta 3), and the delta chain junctional sequences formed a discrete subpopulation compared with those previously reported. 相似文献
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Changelian PS Flanagan ME Ball DJ Kent CR Magnuson KS Martin WH Rizzuti BJ Sawyer PS Perry BD Brissette WH McCurdy SP Kudlacz EM Conklyn MJ Elliott EA Koslov ER Fisher MB Strelevitz TJ Yoon K Whipple DA Sun J Munchhof MJ Doty JL Casavant JM Blumenkopf TA Hines M Brown MF Lillie BM Subramanyam C Shang-Poa C Milici AJ Beckius GE Moyer JD Su C Woodworth TG Gaweco AS Beals CR Littman BH Fisher DA Smith JF Zagouras P Magna HA Saltarelli MJ Johnson KS Nelms LF Des Etages SG Hayes LS Kawabata TT 《Science (New York, N.Y.)》2003,302(5646):875-878
Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings. 相似文献
46.
Elliott WR 《Science (New York, N.Y.)》1967,157(3788):558-559
Yields of free radicals in irradiated aqueous solutions of saccharides at 77 degrees K are larger and qualitatively different from those observed in the components alone. In addition, a blue color results only with the solution. The mechanism proposed to explain the observations is the stabilization of hydrated electrons by the solute. 相似文献
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Batch and upflow column leaching experiments were used to evaluate the nature and extent of Cu and Zn solubilization from contaminated soil by nitrilotriacetic acid (NTA) in 0.025 M NaClO4. In batch soil suspensions, NTA levels of 10?5 to 10?3 M substantially promoted Cu and Zn release from the metal-enriched soil. The ability of NTA to enhance Cu and Zn solubility decreased with increasing solution acidity probably due to competitive binding of NTA by protons and Fe released by hydrous oxide dissolution. However, in the pH range typically encountered in northeastern U.S. soils, soluble metal levels were nearly constant for a given NTA concentration. Leaching soil columns with NTA solutions enhanced Cu release more than Zn, as the enrichment ratio (cumulative metal leached by NTA compared to the 0.025 M NaClO4 control leachate) after 85 pore volumes displacements was 23.6 and 4.3 for Cu and Zn, respectively. While Cu release by 0.01 M CaCl2 differed little from the control, 0.01 M CaCl2 was substantially more effective than 10?5 M NTA in displacing bound Zn. The data reflect different retention mechanisms for Cu and Zn in this soil. 相似文献
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