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2.
Using a previous model, which was developed to describe the light-induced creation of the defect density in the a-Si:H gap states, we present in this work a numerical modelling of the photodegradation effect in the a-Si:H p-i-n solar cell under continuous illumination. We first considered the simple case of a monochromatic light beam with a wavelength λ between 530-540 nm non uniformly absorbed, then the global standard solar spectrum (AM 1.5) illumination is taken into account. The photodegradation is analysed on the basis of the resulting changes in the free carrier's densities, recombination rate, band structure, electrical potential and field, space charge, and current densities. Changes in the cell's external parameters: the open circuit voltage Voc, the short circuit current density Jsc, the fill factor FF and the maximum power density Pmax are also presented. 相似文献
3.
I Ceccarelli F Casamenti C Massafra G Pepeu C Scali AM Aloisi 《Canadian Metallurgical Quarterly》1999,815(2):169-176
In vivo microdialysis was used to assess the effects of novelty and pain on hippocampal ACh release in male and female rats. Experiments were carried out during the dark phase and consisted of 2 days of tests: on Day 1, after Baseline 1, animals were exposed to a new cage (Novelty) to which, 30 min later, a plastic cylinder (Object) was introduced. On Day 2, after Baseline 2, the Formalin test (50 microl of formalin 10%, s.c. injected in the dorsal hindpaw) was carried out in the animal's home cage. All behaviors were recorded. The extracellular levels of ACh in the dorsal hippocampus were estimated, in 10-min samples, by assay of ACh in the dialysates by HPLC. On Day 1 the raw values of ACh were higher in females than in males, but no sex difference was present when the percentage of change was considered. In both sexes the Novelty and Object tests induced an increase in ACh levels with respect to Baseline. Higher levels of exploration were present in females than males during the first 10 min of Novelty. On Day 2, ACh release increased in both sexes during the Formalin test. No sex difference in either ACh raw values or the percentages of change were found. Females showed higher levels of licking and lower levels of activity than males. The present study shows that novelty and pain induce similar hippocampal cholinergic activation in male and female rats but different behaviors. The results are discussed in light of the several anatomical and functional sex differences present in the hippocampus. 相似文献
4.
T Knubovets JJ Osterhout PJ Connolly AM Klibanov 《Canadian Metallurgical Quarterly》1999,96(4):1262-1267
Hen egg-white lysozyme dissolved in glycerol containing 1% water was studied by using CD and amide proton exchange monitored by two-dimensional 1H NMR. The far- and near-UV CD spectra of the protein showed that the secondary and tertiary structures of lysozyme in glycerol were similar to those in water. Thermal melting of lysozyme in glycerol followed by CD spectral changes indicated unfolding of the tertiary structure with a Tm of 76.0 +/- 0.2 degreesC and no appreciable loss of the secondary structure up to 85 degreesC. This is in contrast to the coincident denaturation of both tertiary and secondary structures with Tm values of 74.8 +/- 0.4 degreesC and 74.3 +/- 0.7 degreesC, respectively, under analogous conditions in water. Quenched amide proton exchange experiments revealed a greater structural protection of amide protons in glycerol than in water for a majority of the slowly exchanging protons. The results point to a highly ordered, native-like structure of lysozyme in glycerol, with the stability exceeding that in water. 相似文献
5.
NN Ninkina EM Privalova LG Pin?n AM Davies VL Buchman 《Canadian Metallurgical Quarterly》1999,246(2):308-311
Synucleins constitute a group of unique, evolutionarily conserved proteins that are expressed predominantly in neurons of the central and peripheral nervous system. Although the normal cellular functions of synucleins are not clear, these proteins have been implicated in various neurodegenerative conditions in humans. We found that persyn, a recently characterized member of the synuclein family, is expressed not only in the nervous system but also in the stratum granulosum of the epidermis of neonatal and adult mice. This finding together with our recent observations that persyn influences neurofilament network integrity in sensory neurons raises the possibility that persyn in skin could be involved in modulation of the keratin network. 相似文献
6.
BACKGROUND/AIMS: After liver transplantation for autoimmune hepatitis, the long-term results and the incidence of recurrence of primary disease are unknown. METHODS: In this retrospective study we reviewed the clinical course of 25 patients transplanted for autoimmune hepatitis and followed for a mean of 5.3 years (2-8.5 years). RESULTS: The actuarial 5-year patient and graft survival rates were 91% (+/-6%) and 83% (+/-8%). The actuarial 1-year rate of acute rejection was 50% (+/-10.2%), which was comparable to that of patients transplanted for primary biliary cirrhosis and primary sclerosing cholangitis. Autoantibodies persisted in 77% of patients, at a lower titer than before liver transplantation. Ten patients were excluded from the study of autoimmune hepatitis recurrence, one because of an early postoperative death and nine because of hepatitis C virus infection acquired before or after liver transplantation. In the remaining 15 patients, who were free of hepatitis C virus infection, 5-year patient and graft survivals were 100% and 87%, respectively. Despite triple immunosuppressive therapy, three patients (20%) developed chronic hepatitis with histological and serological features of autoimmune hepatitis in the absence of any other identifiable cause. The disease was severe in two patients, leading to graft failure and asymptomatic in another, despite marked histological abnormalities. In one of these three patients, autoimmune hepatitis recurred on the second liver graft as well. CONCLUSIONS: Patients undergoing liver transplantation for autoimmune hepatitis have an excellent survival rate although severe primary disease may recur, suggesting the need for stronger post-operative immunosuppressive therapy. 相似文献
7.
A seminested PCR assay, based on the amplification of the pneumococcal pbp1A gene, was developed for the detection of penicillin resistance in clinical isolates of Streptococcus pneumoniae. The assay was able to differentiate between intermediate (MICs = 0.25 to 0.5 microgram/ml) and higher-level (MICs = >/=1 microgram/ml) resistance. Two species-specific primers, 1A-1 and 1A-2, which amplified a 1,043-bp region of the pbp1A penicillin-binding region, were used for pneumococcal detection. Two resistance primers, 1A-R1 and 1A-R2, were designed to bind to altered areas of the pbp1A gene which, together with the downstream primer 1A-2, amplify DNA from isolates with penicillin MICs of >/=0.25 and >/=1 microgram/ml, respectively. A total of 183 clinical isolates were tested with the pbp1A assay. For 98.3% (180 of 183) of these isolates, the PCR results obtained were in agreement with the MIC data. The positive and negative predictive values of the assay were 100 and 91%, respectively, for detecting strains for which the MICs were >/=0.25 microgram/ml and were both 100% for strains for which the MICs were >/=1 microgram/ml. 相似文献
8.
AM Avunduk S Yardimci MC Avunduk L Kurnaz A Aydin MC Ko?kar T Deliba?i V Dayanir 《Canadian Metallurgical Quarterly》1999,40(2):537-541
PURPOSE: To evaluate the possible protective effect and mechanism of alpha-tocopherol (vitamin E) treatment on lens degeneration associated with in vivo exposure to cigarette smoke and to further clarify the role of iron in cigarette smoke-generated lens damage. METHODS: Twenty-eight male Wistar rats were randomly divided into four equal groups. Rats in groups 3 and 4 were exposed to cigarette smoke for 1 hour each day over 90 consecutive days, and rats in groups 1 and 2 were treated in similar fashion but only exposed to room air. Additionally, vitamin E was given to the rats in groups 2 and 4 via intramuscular route. At the end of the study, both eyes of all the animals were enucleated; one eye was prepared for histopathologic examination, and the fellow eye was used for the measurement of iron and calcium levels. RESULTS: Significantly higher iron and calcium levels were observed in the lenses of group 3 rats than in other groups. Similar comparisons performed between groups 1 and 2, groups 1 and 4, and groups 2 and 4 did not show any significant difference. Distinct histopathologic changes in the anterior lens epithelium, such as hyperplasia, hypertrophy, epithelial multilayering, and the presence of epithelial cells over posterior lens capsule, observed in group 3 rats were not present in other groups. CONCLUSIONS: Cataractogenesis after cigarette smoke exposure was associated with an accumulation of iron and calcium in the rat lens, and vitamin E supplementation protected such accumulations and cataractogenesis. 相似文献
9.
Tinnitus is the perceived sensation of sound in the absence of acoustic stimulation. Individuals who suffer from it are commonly between the ages of 40 and 80 years. Tinnitus is often classified as objective or subjective, yet the pathophysiologic cause is still unknown. Subjective tinnitus is largely identified with hearing loss. Management of tinnitus is based on an individual approach; there is no single treatment or regimen for it. 相似文献
10.
EA Liberman AM Arzumanian MA Vladimirova LM Tsofina 《Canadian Metallurgical Quarterly》1976,21(3):476-481
"Zero-loop" of the molecular potential transformer of submitochondrial particles (SMP) is separated from the remaining electron transfer chain by rotenone, and its e.m.f. ET=0,003+RT/2F in [NADP X H] [NAD+]/[NADP+] [NAD X H] volts is used in the compensative method of measurement of the potential difference across the SMP membrane (delta USMP). The phospholipid membrane, measuring the concentration of the penetrating anions in the solution contained SMP, is used as "zero-indicators". This concentration drops monotonically with increase in delta USMP. Delta USMP is equal to ET when the addition of substrates of transhydrogenase reaction with definite ET does not change the potential across phospholipid membrane. 相似文献