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排序方式: 共有2225条查询结果,搜索用时 15 毫秒
51.
52.
Andrykowski Michael A.; Carpenter Janet S.; Studts Jamie L.; Cordova Matthew J.; Cunningham Lauren L. C.; Beacham Abbie; Sloan David; Kenady Daniel; McGrath Patrick 《Canadian Metallurgical Quarterly》2002,21(5):485
The impact of benign breast biopsy (BBB) on distress and perceptions of risk for breast cancer (BC) was examined. Interviews were conducted with 100 women shortly after notification of biopsy results and 4 and 8 months post-BBB. Compared with matched healthy comparison (HC) women without BBB, the BBB group evidenced greater BC-specific distress at baseline. BC-specific distress declined after BBB, remaining elevated relative to the HC group at the 8-month follow-up. Dispositional (optimism, informational coping style), demographic (education), clinical (family history of BC), and cognitive (BC risk perception) variables were associated with baseline levels of BC-specific distress or persistence of distress. Results support the monitoring process model (S. M. Miller, 1995) and the cognitive social health information processing model (S. M. Miller, Y. Shoda, & K. Hurley, 1996). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
53.
A dilute mixture of CCl4 in H2 has recently been shown to be a suitable carbon doping source for obtainingp-type GaAs grown by metalorganic chemical vapor deposition (MOCVD) with carbon acceptor concentrations in excess of 1 × 1019cm−3. To understand the effect of growth parameters on carbon incorporation in CCl4 doped Al
x
Ga1−x
As, carbon acceptor concentration was studied as a function of Al composition, growth temperature, growth rate, and CCl4 flow rate using electrochemical capacitance-voltage profiling. The carbon incorporation as a function of Al composition,
growth temperature and CCl4 flow rate was also measured by secondary ion mass spectroscopy (SIMS). All layers were grown by low pressure MOCVD using
TMGa and TMAl as column III precursors, and 100% AsH3 as the column V source. Increased Al composition reduced the dependence of carbon concentration on the growth temperature.
Reduced growth rate, which resulted in substantially decreased carbon acceptor concentrations in GaAs, had an insignificant
effect on the carrier concentration of Al0.4Ga0.6As. A linear relationship between hole concentration and CC14 flow rate in AlxGa1−x
As for 0.0 ≤x ≤ 0.8 was observed. These results are interpreted to indicate that adsorption and desorption of CCl
y
(y ≤ 3) on the Al
x
Ga1-x
As surface during crystal growth plays an important role in the carbon incorporation mechanism. 相似文献
54.
Xuezhe Zheng Lexau J.K. Bergey J. Cunningham J.E. Ron Ho Drost R. Krishnamoorthy A.V. 《Photonics Technology Letters, IEEE》2007,19(7):453-455
Combining the strengths of both proximity communication and optical communication, a new hybrid input-output (I/O) platform delivers on-chip bandwidth off-chip and over distance. We demonstrate, for the first time, a four-channel hybrid I/O interface by integrating proximity communication and vertical-cavity surface-emitting-laser-based parallel optical interconnects on the same commercial 90-nm complementary metal-oxide-semiconductor platform. The optical I/O can operate at 5 Gb/s per channel, and the complete hybrid I/O interface achieved 2.5 Gb/s per channel. We characterize the I/O link performance for various data rates and chip separations, and show 10-mum chip separation tolerance for proximity communication 相似文献
55.
Bcl-xL functions downstream of caspase-8 to inhibit Fas- and tumor necrosis factor receptor 1-induced apoptosis of MCF7 breast carcinoma cells 总被引:1,自引:0,他引:1
A Srinivasan F Li A Wong L Kodandapani R Smidt JF Krebs LC Fritz JC Wu KJ Tomaselli 《Canadian Metallurgical Quarterly》1998,273(8):4523-4529
Stimulation of the Fas or tumor necrosis factor receptor 1 (TNFR1) cell surface receptors leads to the activation of the death effector protease, caspase-8, and subsequent apoptosis. In some cells, Bcl-xL overexpression can inhibit anti-Fas- and tumor necrosis factor (TNF)-alpha-induced apoptosis. To address the effect of Bcl-xL on caspase-8 processing, Fas- and TNFR1-mediated apoptosis were studied in the MCF7 breast carcinoma cell line stably transfected with human Fas cDNA (MCF7/F) or double transfected with Fas and human Bcl-xL cDNAs (MCF7/FB). Bcl-xL strongly inhibited apoptosis induced by either anti-Fas or TNF-alpha. In addition, Bcl-xL prevented the change in cytochrome c immunolocalization induced by anti-Fas or TNF-alpha treatment. Using antibodies that recognize the p20 and p10 subunits of active caspase-8, proteolytic processing of caspase-8 was detected in MCF7/F cells following anti-Fas or TNF-alpha, but not during UV-induced apoptosis. In MCF7/FB cells, caspase-8 was processed normally while processing of the downstream caspase-7 was markedly attenuated. Moreover, apoptosis induced by direct microinjection of recombinant, active caspase-8 was completely inhibited by Bcl-xL. These data demonstrate that Bcl-xL can exert an anti-apoptotic function in cells in which caspase-8 is activated. Thus, at least in some cells, caspase-8 signaling in response to Fas or TNFR1 stimulation is regulated by a Bcl-xL-inhibitable step. 相似文献
56.
M Carrier TK Leung BC Solymoss R Cartier Y Leclerc LC Pelletier 《Canadian Metallurgical Quarterly》1996,61(5):1310-4; discussion 1314-5
BACKGROUND: A prospective, randomized clinical study involving 34 patients undergoing heart transplantation compared myocardial preservation of donor hearts maintained with continuous reperfusion with retrograde warm blood cardioplegia during surgical implantation versus the standard cold topical irrigation. METHODS: Hearts in both groups were arrested with a standard crystalloid solution and maintained in a cold saline solution during transportation. In the retrograde group, cardioplegia was administered through a catheter in the coronary sinus during surgical implantation. An average of 471 +/- 30 mL of hyperkalemic crystalloid solution diluted 1:4 in warm blood from the oxygenator was infused. In the standard group, the heart was kept cold by topical irrigation of cold saline solution and was reperfused only when the ascending aorta was unclamped. RESULTS: Preoperative characteristics of donors and recipients were similar in the two cohorts. Ischemic time average 139 +/- 12 minutes in the retrograde group compared with 130 +/- 11 minutes in the standard group (p = 0.57). Cardiopulmonary bypass time averaged 89 +/- 4 minutes in the retrograde group and 110 +/- 12 minutes in the standard group (p = 0.12). Defibrillation at reperfusion was performed in 4 patients (4/17, 24%) in the retrograde group and 12 patients (12/18, 67%) in the standard group (p = 0.01). There were no deaths in the retrograde group (0/17), whereas in the standard group, 3 patients (3/17) died of early graft failure (p = 0.11). Four early graft failures occurred in the standard group (p = 0.06). Two patients (2/17, 12%) were weaned from bypass with ventricular assist devices in the standard group. The number of subendocardial necrotic cells in the first two weekly endomyocardial biopsy specimens averaged 2.7 +/- 0.8 cells/mm2 in the retrograde group and 5.9 +/- 2.4 cells/mm2 in the standard group (p = 0.12). CONCLUSIONS: Retrograde warm blood reperfusion appears to improve the initial recovery of transplanted hearts. The technique is easy to use and may be a useful approach to graft protection during surgical implantation. 相似文献
57.
PR Jefferies TA Blumenkopf PJ Gengo LC Cole JE Casida 《Canadian Metallurgical Quarterly》1996,39(12):2331-2338
Ryanodine (1) and dehydroryanodine (2) have a polar face formed by cis-hydroxyls at C-2, C-4, C-6, and C-12. The importance of the hydroxyls to the action of 1 and 2 at the ryanodine receptor (ryr) of calcium release channels is examined at [3H]-1 binding sites in brain and skeletal muscle and in heart membranes relative to cardiac contractility, a pharmacologic response which appears to be mediated by the ryr. Five types of changes are considered: blocking the 4- and 6-hydroxyls as cyclic borates and boronates; blocking the 10- and 12-hydroxyls as cyclic phosphates, phosphonates, and phosphoramidates; methylation at nitrogen or hydroxyls at C-4 and C-10; dehydration of the C-2 hydroxyl; additional data for a 4,12-oxygen-bridged series. The first change has little effect on potency possibly due to the lability of the boron protective groups whereas the cyclic phosphorus compounds have reduced activity. Methylation reduces potency the least at nitrogen and the C-4 hydroxyl. Dehydration of 1 to 2-deoxy-2(13)-dehydro-1 allows the restoration of oxygen at C-2 by conversion to epoxides or a diol. One of the epoxides and 2-deoxy-2(13)-dehydro-2 retain 8-31% of ryanodine's potency in the ryr assays and 81% in the cardiac contractility system. In the 4,12-oxygen-bridged series, high potency at the receptor and cardiac muscle is retained in the 4-hydroxy ketal. 相似文献
58.
59.
Szucs Regina P.; Frankel Paul S.; McMahon Lance R; Cunningham Kathryn A. 《Canadian Metallurgical Quarterly》2005,119(5):1173
Serotonin 5-HT2A receptor antagonists have been shown to attenuate the locomotor stimulant effects of cocaine in rats. The present study used the expression of c-Fos protein as a marker to identify brain areas through which 5-HT2A receptors may modulate cocaine-induced behaviors. Significant correlations were observed between cocaine-induced hyperactivity and c-Fos expression in the nucleus accumbens core (NAcC), caudate-putamen (CPu), and subthalamic nucleus. In a separate experiment, a low, behaviorally relevant dose of cocaine was found to increase c-Fos immunoreactivity in the medial CPu, NAcC, and nucleus accumbens shell (NAcSh). The selective 5-HT2A receptor antagonist M100907 significantly attenuated cocaine-induced c-Fos expression in the medial CPu and in the NAcSh. These data suggest that 5-HT2A receptors in the NAcSh and CPu or in afferents to these regions may contribute to genomic responses to cocaine in the brain as well as to cocaine-induced locomotor activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.