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991.
In this paper, a positive effect of rapid thermal annealing (RTA) technique has been researched and compared with conventional furnace annealing for Si nanocrystalline in silicon carbide (SiC) matrix system. Amorphous Si-rich SiC layer has been deposited by co-sputtering in different Si concentrations (50 to approximately 80 v%). Si nanocrystals (Si-NC) containing different grain sizes have been fabricated within the SiC matrix under two different annealing conditions: furnace annealing and RTA both at 1,100°C. HRTEM image clearly reveals both Si and SiC-NC formed in the films. Much better "degree of crystallization" of Si-NC can be achieved in RTA than furnace annealing from the research of GIXRD and Raman analysis, especially in high-Si-concentration situation. Differences from the two annealing procedures and the crystallization mechanism have been discussed based on the experimental results.  相似文献   
992.
Bacterial biosynthesis of indole-3-acetic acid   总被引:1,自引:0,他引:1  
Production of the phytohormone indole-3-acetic acid (IAA) is widespread among bacteria that inhabit the rhizosphere of plants. Several different IAA biosynthesis pathways are used by these bacteria, with a single bacterial strain sometimes containing more than one pathway. The level of expression of IAA depends on the biosynthesis pathway; the location of the genes involved, either on chromosomal or plasmid DNA, and their regulatory sequences; and the presence of enzymes that can convert active, free IAA into an inactive, conjugated form. The role of bacterial IAA in the stimulation of plant growth and phytopathogenesis is considered.  相似文献   
993.
Using [14C] 2-deoxyglucose (2-DG) autoradiography with computerized densitometric analysis, unilateral foot pinch was found to significantly increase the relative optical density in laminae I and II of the ipsilateral, compared to the contralateral, spinal cord at lumbar 5 (L5). However, during vaginocervical mechanostimulation applied concurrently with the unilateral foot pinch, no comparable difference was observed. No response to foot pinch was observed in other laminae of the spinal cord at L5, and no effects comparable to the above were observed at L3. These findings indicate that vaginocervical mechanostimulation suppresses neural responses to noxious foot pinch stimulation selectively at the laminae I and II level of the spinal cord at L5, but not at L3.  相似文献   
994.
Inducible-Nitric oxide synthase (iNOS, EC 1.14.13.39) catalyzes the formation of nitric oxide (NO) and L-citrulline from L-Arg. NADPH and dioxygen. The natural product, (-)-noformycin was found to be a potent, competitive inhibitor of recombinant human iNOS with respect to L-Arg with a Ki = 1.3 +/- 0.3 microM. The reversible binding of noformycin caused a high spin type I spectral perturbation of the iNOS heme group with a Kd = 1.5 +/- 0.2 microM. These results demonstrate that natural products may be a useful source for inhibitors of NO-biosynthesis.  相似文献   
995.
(+)-cis-3,5-dimethyl-2-(3-pyridyl)thiazolidin-4-one hydrochloride (SM-12502) was oxidized by human liver microsomes to produce the S-oxide as a sole metabolite. Indirect evidence suggested that the S-oxidation was catalyzed by cytochrome P450 (CYP). Eadie-Hofstee plots showed biphasic pattern, suggesting that at least two enzymes were involved in the S-oxidation in human liver microsomes. Kinetic parameters of the S-oxidase with high-affinity showed Km and Vmax values of 20.9 +/- 4.4 microM and 0.111 +/- 0.051 nmol/min/mg microsomal protein, respectively. The S-oxidase activity was inhibited by coumarin and anti-CYP2A antibody. Among the contents of forms of CYP 20 samples of human liver microsomes, the content of CYP2A6 correlated with S-oxidase activity measured with 50 microM SM-12502 (r = .808, P < .0005). A close correlation (r = .908, P < .0001) was observed between activities of SM-12502 S-oxidase and coumarin 7-hydroxylase. Microsomes from genetically engineered human B-lymphoblastoid cells expressing CYP2A6 metabolized SM-12502 to the S-oxide efficiently. The results indicate that CYP2A6 isozyme is a major form of CYP responsible for the S-oxidation of SM-12502 in human liver microsomes. Thus, SM-12502 will be a useful tool in further research to analyze a human genetic polymorphism of CYP2A6.  相似文献   
996.
The development of liver transplantation has led to technical refinements such as liver graft reduction or splitting for transplantation in two recipients, the use of living related donors, and the temporary orthotopic transplantation of auxiliary liver grafts. Regarding immuno-suppression, new drugs are currently under evaluation, such as tacrolimus (FK 506) which could be effective on some severe rejections. On the other hand, the indications of liver transplantation have been revisited according to clinical results. In France, the increasing development of organ and tissue transplantation has led to the creation of the Etablissement Fran?ais des Greffes, which has the following missions: managing the waiting lists, supporting organ donation, ensuring sanitary safety, and evaluating transplantation activities. Future alternatives to allogenic liver transplantation are mainly represented by xenografting with monkey or pig livers, hepatic assistance and bioartificial liver, and gene therapy.  相似文献   
997.
998.
delta 8-Tetrahydrocannabinol (delta 8-THC) is a naturally occurring cannabinoid with a characteristic pharmacological profile of in vivo effects. Previous studies have shown that modification of the structure of delta 8-THC by inclusion of a nitrogen-containing functional group alters this profile and may alkylate the cannabinoid receptor, similar to the manner in which beta-funaltrexamine (beta-FNA) alkylates the micro-opioid receptor. Two novel analogs of delta 8-THC were synthesized: a nitrogen mustard analog with a dimethylheptyl side chain (NM-delta 8-THC) and a cyano analog with a dimethylpentyl side chain (CY-delta 8-THC). Both analogs showed high affinity for brain cannabinoid receptors and when administered acutely, produced characteristic delta 9-THC-like effects in mice, including locomotor suppression, hypothermia, antinociception and catalepsy. CY-delta 8-THC shared discriminative stimulus effects with CP 55,940; for NM-delta 8-THC, these effects also occurred, but were delayed. Although both compounds attenuated the effects of delta 9-THC in the mouse behavioral tests, evaluation of potential antagonist effects of these compounds was complicated by the fact that two injections of delta 9-THC produced similar results, suggesting that acute tolerance or desensitization might account for the observations. NM-delta 8-THC, but not CY-delta 8-THC, attenuated the discriminative stimulus effects of CP 55,940 in rats several days following injection. Hence, addition of a nitrogen-containing functional group to a traditional cannabinoid structure does not eliminate agonist effects and may produce delayed attenuation of cannabinoid-induced pharmacological effects.  相似文献   
999.
Distal biceps brachii tendon ruptures occur much less frequently than do their proximal counterparts. Distal tendon ruptures usually are associated with considerable function deficits and may require surgical treatment. Repair of chronic distal biceps brachii ruptures are extremely unusual. A free autogenous semitendinosus tendon graft was used to reconstruct the distal biceps tendon by reattaching the graft to the radial tuberosity via a 2-incision technique in a patient with symptoms and a chronic injury.  相似文献   
1000.
The effects of urinary symptoms on health-related quality of life (HRQL) are important in therapeutic decision making. Few have evaluated the treatment effects on HRQL in men with benign prostatic hyperplasia (BPH), even though increased urinary symptoms are associated with greater worry, bother, and interference with living activities. We report on patient assessments of such disease-specific measures as well as general HRQL measures from two placebo-controlled clinical trials of finasteride in the treatment of symptomatic BPH. Patients treated with finasteride appeared to have greater improvement than placebo-treated patients in disease-specific measures and in patient global assessment. The treated group appeared to have a greater mean increase in sexual domain scores. As expected, general measures (health rating, life satisfaction, ladder of life) changed little. Thus, treatment with finasteride appears to reduce bother, worry, and activity interference due to symptoms but in a small percentage of men may lead to slightly reduced sexual function.  相似文献   
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