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1.
In this study we have investigated the role of CD4+, MHC class II-restricted cytotoxic T lymphocytes (CTLs) in the disease caused by lymphocytic choriomeningitis virus (LCMV) in beta 2-microglobulin deficient (beta 2m-) mice. Intracranial (i.c.) infection with LCMV resulted in death of six out of 11 beta 2m- mice. Mice that survived showed a marked loss in body weight. Death and loss of body weight could be prevented by immunosuppressing the mice with irradiation or cyclosporine prior to i.c. injection of LCMV. This treatment also prevented induction of virus-specific, MHC class II-restricted CTL following peripheral inoculation with LCMV. In vivo depletion of CD4+ cells with antibody also prevented death following i.c. injection whereas in vivo depletion of CD8+ cells had no effect. Disease could be transferred to recipient beta 2m- mice by adoptive transfer of beta 2m- derived immune spleen cells. Transfer of non-immune spleen cells did not result in illness. In vitro treatment of immune spleen cells with anti-CD4 antibody and complement eliminated class II-restricted CTL activity and also prevented mortality of recipients after adoptive transfer. Treatment with anti-CD8 antibody had no effect. We were unable to transfer LCM disease to beta 2m- recipients by adoptive transfer of immune spleen cells from C57BL/6 mice. These results suggest that, unlike normal mice, the pathology of LCM disease in beta 2m- mice is dependent upon virus-specific, CD4+CD8-, MHC class II-restricted T cells. 相似文献
2.
Gunapala S.D. Bundara S.V. Liu J.K. Winn Hong Mani Sundaram Maker P.D. Muller R.E. Shott C.A. Carralejo R. 《Electron Devices, IEEE Transactions on》1998,45(9):1890-1895
A 9-μm cutoff 640×486 snap-shot quantum well infrared photodetector (QWIP) camera has been demonstrated. The performance of this QWIP camera is reported including indoor and outdoor imaging. The noise equivalent differential temperature (NEΔT) of 36 mK has been achieved at 300 K background with f/2 optics. This is in good agreement with expected focal plane array sensitivity due to the practical limitations on charge handling capacity of the multiplexer, read noise, bias voltage, and operating temperature 相似文献
3.
Analysis of electrocardiograms during atrial fibrillation 总被引:1,自引:0,他引:1
Vincent Jacquemet Adriaan van Oosterom Jean-Marc Vesin Lukas Kappenberger 《IEEE engineering in medicine and biology magazine》2006,25(6):79-88
The research discussed in this article is motivated by the search for an optimal classification of the different types of atrial fibrillation (AF) on the basis of recorded atrial signals. This would facilitate the selection of an optimal therapy. This article focuses on the biophysical models of the genesis of ECG waveforms during AF. The model of the electric activity of the atria was found to have sufficient realism to be used to describe the electric sources during AF. The inclusion of the volume conduction model resulted in electrocardiographic signals that are in all aspects similar to those observed clinically. The model is currently applied to solve various problems related to optimal signal preprocessing and extraction of features in AF signals for the classification of AF abnormalities. The biophysical model of the atrial activity is an essential element in this research, since it is capable of describing the electric source specifications derived from different hypotheses relating to the etiology of AF 相似文献
4.
5.
SiC-based field-effect gas sensors with catalytic platinum electrodes (Pt-MOSiC) have been subjected to a series of gas response measurements. Structural analysis of the Pt electrodes revealed that the gas sensitivity and the selectivity of Pt-MOSiC gas sensors depend on two major parameters: the porosity and the catalytic activity of the Pt electrodes. Pt-MOSiC gas sensors with thick, dense Pt electrodes only exhibit hydrogen sensitivity, whereas Pt-MOSiCs with thin porous gates exhibit a broad range of gas sensitivities similar to resistive metal-oxide gas sensors. A model is put forward that explains the nonhydrogen gas response of Pt-MOSiC devices and of conventional polycrystalline metal-oxide materials on a common basis. 相似文献
6.
7.
Averin S.V. Kohl A. Muller R. Mesquida Kusters A. Wisser J. Heime K. 《Electronics letters》1992,28(11):992-995
The p/sup +/-cap layer was used to fabricate a metal-semiconductor-metal (MSM) interdigitated photodetector on Ga/sub 0.47/In/sub 0.53/As. The measured barrier height was Phi /sub Bn=/0.52 V, the ideality factor n=1.1 and average dark current density 2 mA/cm/sup 2/. A rise time of 45 ps at lambda =1.3 mu m under 2 V bias was measured for an MSM photodiode with 3 mu m finger width and finger gaps and an active area of 100*100 mu m/sup 2/.<> 相似文献
8.
JR Perry SS Deodhare JM Bilbao D Murray P Muller 《Canadian Metallurgical Quarterly》1993,32(2):157-162
Sex hormones have profound effects on immune responses and may influence the outcome of autoimmune diseases such as rheumatoid arthritis (RA). We investigated the effect of gonadal steroids on the production of interleukin-1 (IL-1) and IL-6, cytokines believed to be important in the pathogenesis of RA. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy male donors and male patients with RA, and were stimulated with lipopolysaccharide (LPS) in the presence of different concentrations of 17-beta-estradiol, progesterone or testosterone. In studies of cells from normal male donors, 17-beta-estradiol at pharmacological concentrations (> or = 10(-6) M) enhanced IL-1 and IL-6 secretion as well as the production of cell-associated IL-1. Progesterone and testosterone at similar concentrations inhibited IL-1 secretion but had no significant effect on IL-6 secretion or on the production of cell-associated IL-1. In studies of male RA donors, 17-beta-estradiol failed to enhance IL-1 or IL-6 secretion and progesterone failed to inhibit IL-1 secretion. The inhibitory effects of testosterone, however, appeared to be similar to that in normal donors. It is suggested that 17-beta-estradiol may promote IL-1 and IL-6 production and release, while gestation hormone, progesterone, and testosterone may inhibit IL-1 release in vivo. These data may partly explain the gender and age differences in the incidence of RA and the development of the disease in men with low and androgen levels. 相似文献
9.
Afam I Jideani Richard K Owusu Apenten H G Muller 《Journal of the science of food and agriculture》1994,65(4):465-476
The effect of cooking on proteins from acha and durum wheat was assessed from an analysis of protein extractability, gel electrophoretic profiles, in-vitro protein digestibility (IVPD) and the amino acid compositions of wholemeal flour and residue proteins. Heating wholemeal flour samples at 100–140°C (t = 10–40 min) resulted in 0–30% and 45–55% decreases in acha and durum protein solubility, respectively. In general, high molecular weight (30–70 k Da) protein subunits were more susceptible to heat damage. For both cereals, sodium dodecyl sulphate (SDS; 10 g litre?1) and/or dithiothrcitol (DTT; 10 mM ) increased protein solubility in unheated and heated samples. The IVPD index was 90–91% and was not significantly altered by cooking (100–120°C, t = 40 min). Cooking at extreme temperatures (140°C, t = 40 min) reduced the IVPD by 8% (P = 0.05). Osborne fractionation resulted in a durum or acha residue level of 7.8% or 55.2%. Treatment with solvent containing propanol, SDS and/or DTT at room temperature followed by SDS-polyacrylamide gel electrophoresis of non-solubilised proteins showed that the glutelin fraction of acha, with the exception of a 65 kDa subunit, was insoluble owing to strong inter-subunit hydrophobic and disulphide interactions. Wholemeal acha flour and residue protein showed a significantly greater level of hydrophobic and sulphur amino acids as well as glutamine which is associated with H-bonding. The possibility that cereal protein solubility is also dependent on protein-carbohydrate links is discussed. 相似文献
10.
Schnepp H. Muller T. Luy J.-F. Russer P. 《Microwave and Wireless Components Letters, IEEE》2003,13(8):323-325
A novel channel diversity concept is proposed and demonstrated, which avoids receiving signal deterioration due to multipath fading in mobile receivers. The system is based on coherent superposition of the signals received from several transmitters supplying the same information at different frequencies. Based on a software radio architecture this concept may increase the quality of mobile reception in modern car receivers considerably. Compared with multiantenna-receivers which overcome the multipath fading problem by simultaneously receiving the same program with several antennas, the proposed solution is advantageous, since it requires only a single antenna. 相似文献