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排序方式: 共有92条查询结果,搜索用时 93 毫秒
1.
Wireless Personal Communications - Complementary coded code-division multiple access (CC-CDMA) has been originated as one of the extremely robust multiuser access technique in designing high data... 相似文献
2.
Ben L. O’Connor Miki Hondzo Judson W. Harvey 《Canadian Metallurgical Quarterly》2009,135(12):1304-1314
Traditionally, dissolved oxygen (DO) fluxes have been calculated using the thin-film theory with DO microstructure data in systems characterized by fine sediments and low velocities. However, recent experimental evidence of fluctuating DO concentrations near the sediment-water interface suggests that turbulence and coherent motions control the mass transfer, and the surface renewal theory gives a more mechanistic model for quantifying fluxes. Both models involve quantifying the mass transfer coefficient (k) and the relevant concentration difference (ΔC). This study compared several empirical models for quantifying k based on both thin-film and surface renewal theories, as well as presents a new method for quantifying ΔC (dynamic approach) that is consistent with the observed DO concentration fluctuations near the interface. Data were used from a series of flume experiments that includes both physical and kinetic uptake limitations of the flux. Results indicated that methods for quantifying k and ΔC using the surface renewal theory better estimated the DO flux across a range of fluid-flow conditions. 相似文献
3.
Judson P.D.L. Groom K.M. Childs D.T.D. Hopkinson M. Hogg R.A. 《Optoelectronics, IET》2009,3(2):100-104
The design and operating parameters of a novel multi-contact quantum dot superluminescent diode incorporating a number of features which inhibit lasing are described and compared with that of a single-contact device. Such devices allow the independent tuning of emission power and spectral shape; hence the penetration depth and resolution in optical coherence tomography are decoupled. The emission spectrum of a device utilising chirped quantum dots is shown to be tuned to produce a broadband single Gaussian emission, centred at the required wavelength of 1050 nm, at higher output powers than a singlecontact device. 相似文献
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As the effects on injury scaling of the differences between the 1980 and 1985 revisions of the AIS are unknown in blunt trauma, we compared them in all 1270 critically injured (median ISS, 26) blunt trauma patients (75% male, 74% road crash, overall mortality 17%) admitted to the Department of Critical Care Medicine at Auckland Hospital from 1983 through 1987. In 911 patients (72%) there were no differences between AIS-80 and AIS-85 in any body region or in derived ISS. Changes in AIS grades were most common in the abdomen (205 patients), thorax (100 patients), and head (61 patients) regions. Median ISS overall for the 1270 patients was unchanged at 26. One percent of patients had changes in ISS of 16-24 points. Direct comparison of groups of patients scored with these two revisions of the AIS is inappropriate, particularly in those with abdomen region injury. 相似文献
6.
JR Hibbs JM Douglas FN Judson WL McGill CA Rietmeijer EN Janoff 《Canadian Metallurgical Quarterly》1997,25(2):195-199
The hemagglutinating virus of Japan (HVJ)-liposome method involves the entrapment of DNA and nuclear protein within liposomes and the use of HVJ to enhance liposome fusion with cell membranes. This method has been used successfully for in vivo gene transfer to various types of tissue. In this study, we investigated whether this method transfers genes effectively to normal and malignantly transformed keratinocytes in vivo. We applied HVJ-liposome complex (HLC) containing the beta-galactosidase gene to the tape-stripped skin of hairless rats and detected the enzyme activity in the keratinocytes of the treated skin. Comparison of this method with the naked DNA injection method, which was shown recently to be useful for in vivo gene transfer to keratinocytes, demonstrated that the transfer efficiency of the latter was about 5 times higher than that of the former. We assessed the efficacy of the HVJ-liposome method for gene transfer to transformed keratinocytes by examining the effect of HLC containing the herpes simplex virus thymidine kinase gene on the growth of mouse squamous cell carcinomas. Local injection of HLC into the tumors followed by administration of ganciclovir to mice resulted in tumor growth inhibition. These results indicate that the HVJ-liposome method is suitable for in vivo gene transfer to keratinocytes; also that this method may prove a good tool for basic research into keratinocyte biology and future keratinocyte gene therapy. 相似文献
7.
LJ Conley TJ Bush SP Buchbinder KA Penley FN Judson SD Holmberg 《Canadian Metallurgical Quarterly》1996,10(10):1121-1126
OBJECTIVE: To clarify the effect of cigarette smoking on the development of conditions associated with HIV infection. DESIGN: Prospective and retrospective cohort study, with interview and examination twice a year since 1988. METHODS: Data on 516 HIV-infected men from cohorts of homosexual and bisexual men in San Francisco, Denver and Chicago, who were repeatedly interviewed and examined between 1988 and 1992, were analysed. After excluding men who did not have well-defined dates of seroconversion and those who were classified as ex- or intermittent smokers, 232 men remained for analysis: 106 were smokers and 126 were non-smokers. Univariate and Kaplan-Meier survival analyses were performed to assess the relationship between cigarette smoking and loss of CD4+ T-lymphocytes, diagnosis of any AIDS-defining illness, and specific diagnosis of Kaposi's sarcoma, Pneumocystis carinii pneumonia (PCP), oral candidiasis, hairy leukoplakia, and community-acquired pneumonia. RESULTS: By univariate analyses, cigarette smoking was not associated with clinical AIDS, loss of CD4+ cells, Kaposi's sarcoma or PCP, but was significantly associated with oral candidiasis [relative risk (RR), 1.32; 95% confidence interval (CI), 1.02-1.70], hairy leukoplakia (RR, 1.51; 95% CI, 1.15-1.99), and community-acquired pneumonia (RR, 2.62; 95% CI, 1.30-5.27). Dose-response effect was also evident for these three conditions (all P < 0.01). Kaplan-Meier survival analysis indicated no association between cigarette smoking and time of progression to clinical AIDS, Kaposi's sarcoma (KS), or PCP (P = 0.62, 0.54 and 0.11, respectively) but showed that cigarette smokers developed oral candidiasis, hairy leukoplakia, and pneumonia more quickly than non-smokers (P = 0.031, 0.006 and 0.009, respectively). CONCLUSIONS: Cigarette smoking was not associated with an increased likelihood or rate of developing KS, PCP or AIDS, but was associated with developing community-acquired pneumonia, oral candidiasis, and hairy leukoplakia in these HIV-infected men. 相似文献
8.
M Jarman HM Coley IR Judson TJ Thornton DE Wilman G Abel CJ Rutty 《Canadian Metallurgical Quarterly》1993,36(26):4195-4200
In exploring the structural features which determine the antitumor activity of 2,4,6-tris-[(hydroxymethyl)methylamino]-1,3,5-triazine (trimelamol, 1), we have synthesized analogues in which the methyl groups have been replaced by the electron-withdrawing substituents 2,2,2-trifluoroethyl (5), propargyl (13), and cyanomethyl (15) via the respective tris(alkylamino)triazines 3, 12, and 14. Three mono[(hydroxymethyl)amino]triazines (4, 7, and 10) were also prepared. All the new tris(hydroxymethyl) derivatives showed cytotoxicities toward a variety of experimental rodent and human ovarian tumor cell lines similar to those shown by 1, the cyanomethyl analogue (15) having the most favorable profile. Mono(hydroxymethyl) derivatives (4 and 7) were ca. one-third as toxic. The new tris(hydroxymethyl) analogues were more stable to aqueous hydrolysis than was 1. Half-life (pH 7.5) values were, for 1, 120 min, for 5, 690 min, for 13, 450 min, and for 15, 275 min, but at pH 2.0, 15 (t1/2 350 min) was the most stable. This cyanomethyl analogue was also the most water-soluble, being comparable to 1 whereas 5 and 13 were poorly soluble. 相似文献
9.
O'Donnell Meaghan L.; Creamer Mark C.; Parslow Ruth; Elliott Peter; Holmes Alexander C. N.; Ellen Steven; Judson Rodney; McFarlane Alexander C.; Silove Derrick; Bryant Richard A. 《Canadian Metallurgical Quarterly》2008,76(6):923
Posttraumatic stress disorder (PTSD) and major depressive episode (MDE) are frequent and disabling consequences of surviving severe injury. The majority of those who develop these problems are not identified or treated. The aim of this study was to develop and validate a screening instrument that identifies, during hospitalization, adults at high risk for developing PTSD and/or MDE. Hospitalized injury patients (n = 527) completed a pool of questions that represented 13 constructs of vulnerability. They were followed up at 12 months and assessed for PTSD and MDE. The resulting database was split into 2 subsamples. A principal-axis factor analysis and then a confirmatory factor analysis were conducted on the 1st subsample, resulting in a 5-factor solution. Two questions were selected from each factor, resulting in a 10-item scale. The final model was cross-validated with the 2nd subsample. Receiver-operating characteristic curves were then created. The resulting Posttraumatic Adjustment Scale had a sensitivity of .82 and a specificity of .84 when predicting PTSD and a sensitivity of .72 and a specificity of .75 in predicting posttraumatic MDE. This 10-item screening index represents a clinically useful instrument to identify trauma survivors at risk for the later development of PTSD and/or MDE. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献
Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology. 相似文献