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排序方式: 共有1920条查询结果,搜索用时 15 毫秒
991.
M del Cerro SZ Child CH Raeman EL Carstensen MW Miller 《Canadian Metallurgical Quarterly》1994,20(9):981-986
Neonatal rats were exposed or sham exposed for 30 min to pulsed ultrasound [2.25 MHz carrier frequency, 1 microsecond pulse length, 50 Hz pulse repetition frequency (PRF), 50 W/cm2 Imax, 2 mW/cm2 ITA], euthanised and prepared for electron microscopic analysis of the nodes of Ranvier of the dorsal and ventral roots of the spinal cord. There was also a cage control. All materials were processed and scored blindly, evaluating whether perinodal myelin was normal. Rats from all regimens had areas of disrupted myelination. There was no statistically significant difference among the regimens for absence of myelination. The results did not confirm an earlier report that diagnostic ultrasound disrupts myelination in neonatal rats. 相似文献
992.
The main results obtained in the small tokamak TBR-1 of University of São Paulo (USP) are reviewed. The main effort has been concentrated on the characterization and external control of MHD activity, plasma edge phenomena and diagnostic development. The design of a small-aspectratio tokamak, TBR-E, and the research program to be carried out in TCA, to be transferred from Lausanne to São Paulo, are also briefly described. 相似文献
993.
CS North DE Pollio SJ Thompson DA Ricci EM Smith EL Spitznagel 《Canadian Metallurgical Quarterly》1997,33(6):531-543
OBJECTIVE: This study compared psychiatric diagnoses ascertained by independent clinicians with structured research interviews of homeless psychiatric patients assessed in a mental health clinic and in the community. Problems of both overdiagnosis and underdiagnosis in structured research interviews compared to clinician assessment were predicted. METHOD: Over a period of a year, 97 patients referred to a mental health clinic for homeless people were assessed with the Diagnostic Interview Schedule (DIS) administered by a clinical social worker who then completed a full clinical psychiatric social work assessment. These same patients received a thorough and systematic clinical psychiatric evaluation by a psychiatrist or psychologist, both experienced with this population. These clinicians gathered data from multiple sources, often with extended observation over time. The DIS and clinician diagnoses were made blind to one another and then compared; the clinician was often made aware of some of the symptoms that the social worker had elicited, but not whether the elicited material was from the DIS or from the clinical assessment. Diagnoses of 33 clinic patients previously assessed by trained nonclinician DIS interviews in an epidemiologic study of the homeless population in the community were also compared to clinician diagnoses, and no information from these patients' survey DIS interviews was made available to the clinicians. RESULTS: Compared to clinician assessment, structured interviews underdiagnosed antisocial personality disorder (ASPD) and overdiagnosed major depression. Alcohol use disorder and schizophrenia showed only small discrepancies by assessment method. Drug use disorder revealed no bias according to method of ascertainment, but showed very discrepant kappa levels comparing DIS to clinician assessment in the two different comparison contexts. CONCLUSIONS: If structured research methods assessing the homeless population actually overestimate depression, underestimate ASPD, and misclassify drug abuse, then policies stemming from structured interview research recommendations may call for levels and types of services not optimally suited to the reality of this population's needs. Because mental illness and substance abuse are thought to be critical factors in the generation and perpetuation of homelessness, the issue of accurate diagnosis is tantamount to understanding and providing workable solutions to the problem of homelessness. Further research is needed to untangle potential confounders of the homeless situation to psychiatric diagnosis. 相似文献
994.
Plasma human immunodeficiency virus type 1 (HIV-1) populations were genetically analyzed at their most variable locus, the envelope gene, during the rapid emergence of resistance to protease inhibitor monotherapy. Plasma virus populations remained genetically constant prior to drug treatment and during the 1 to 2 weeks following initiation of therapy, while viremia fell 10- to 100-fold. Concomitant with rapid plasma viremia rebounds associated with the emergence of drug-resistant virus, marked alterations were then detected at the env locus. Plasma population changes lasted only a few weeks before the reappearance of the pretreatment envelope variants. The emergence of resistance to single protease inhibitors was therefore associated with major but transient changes at a nonselected locus. Selection for resistance to single protease inhibitors thus appears to be more complex than the continued replication of a large, random, and therefore genetically representative sampling of the pretreatment plasma population. The possibility that drug-privileged anatomical sites containing distinct envelope variants and/or a small effective HIV-1 population size account for these results is discussed. 相似文献
995.
PW Jungnickel PA Maloley EL Vander Tuin TE Peddicord JR Campbell 《Canadian Metallurgical Quarterly》1997,12(10):591-596
OBJECTIVE: To compare the effects of pretreatment with two aspirin regimens and placebo on niacin-induced cutaneous reactions. DESIGN: Randomized, double-blind, placebo-controlled, crossover study. SETTING: Internal medicine clinic in an academic health center. PARTICIPANTS: Forty-two healthy subjects (22 males and 20 females) between the ages of 35 and 65 (mean age 44.2 years) were recruited and completed the study. Subjects received aspirin 325 mg, aspirin 650 mg, and placebo for 4 consecutive days, and on the fourth day also ingested 500 mg of immediate-release niacin 30 minutes after taking aspirin or placebo. They reported the intensity of flushing, headache, pruritus, tingling, and warmth on a 10-cm visual analogue scale. Reactions were evaluated at time 0 (before the niacin dose), and at 15, 30, 60, and 120 minutes following the niacin dose. Cutaneous reactions were compared at each evaluation time and scored by two other methods. The peak intensity was the highest score recorded at any of the four evaluation times after niacin administration. An intensity-time factor was calculated by totaling the scores of each of the four evaluation times. MEASUREMENT AND MAIN RESULTS: The symptom scores for flushing, itching, tingling, and warmth were all significantly reduced by both aspirin regimens (p < .05 in all cases), although there were no significant differences between the 325-mg and 650-mg doses. The results were similar for each scoring method. CONCLUSIONS: An aspirin regimen of 325 mg is effective in suppressing niacin-induced cutaneous reactions. Increasing the dose to 650 mg does not provide additional benefit. 相似文献
996.
997.
Photoecological consequence of ozone holes are considered. Analysis of the total UV-radiation intensity and the short-wave edge of atmospheric transmittance depending on ozone content is presented. Characteristic times of some photodamages to skin and eyes have been estimated under ozone content reducing. A role of photosensitizers including drugs in phototoxical effects is discussed. Possible ways of photoprotection are considered. 相似文献
998.
After being weaned, the Wistar rats (12) were fed on a sucrose diet for five weeks to induce dental caries. Tetracycline was injected intraperitoneally into 7 of them to label the mineralizing dentin front. Five rats without tetracycline injection were used to verify spontaneous fluorescence. The evidently carious area under one prominent fissure from each mandibular molar hemisected sagittally in the midline was photographed under ultraviolet light so that autofluorescence would be revealed. The jaws were then stained with Schiff's reagent and photographed under normal light and again under ultraviolet light. The areas of all the lesions were quantified planimetrically as they appeared on the photographs. The mineral contents of the areas were verified with the back-scattered electron images. The caries lesions revealed with Schiff's reagent also exhibited a change in the color of the dentin fluorescence regardless of the tetracycline labeling. The areas of these lesions followed the shapes of the lesions stained by Schiff's reagent but they were greater. Staining with Schiff's reagent was repeatable after the specimen was washed with ethanol for a few weeks. The loss of minerals was seen in the areas stained with Schiff's reaction but was also related to the change in dentin fluorescence, which seems to be a more sensitive indicator of the caries progression than Schiff's reagent, especially in the early phase of the carious process. 相似文献
999.
OBJECTIVE: We present current concepts and assess the quality of information available for the prevention of cardiovascular disease in women. METHODS: This article reviews research bearing on the prevention of cardiovascular disease in women, with particular attention to modifiable risk factors. We describe the magnitude of the problem and assess the quality of the data with respect to the classic risk factors. The concept is emphasized that changes at menopause, states of endocrine aberration, and benefits and risks of hormone substitution and oral contraception must be understood in conjunction with all other potentially modifiable and nonmodifiable risk factors. CONCLUSIONS: Primary care physicians, especially obstetrician/gynecologists, have a pivotal role to play in the reduction of this disease. Behavior modification is the key to integrating prevention into the regular annual visit. 相似文献
1000.
Kazem M. Sadeghi Henrique C. G. do Nascimento Mohammad-Ali Sadeghi Lian Sheng Wang Yu Wang Teh Fu Yen 《Petroleum Science and Technology》1994,12(10):1393-1412
A solvent refining coal liquefaction process recycle water (No. 3) from Du Pont, Washington, a true in-situ oil shale retort water (Omega-9) from Rock Springs, Wyoming, and a ten-ton unit simulated in-situ oil shale retort water (No, 16) from Laramie, Wyoming, were subjected to solvent extraction procedure and subsequent instrumental analysis including: (a) high performance liquid chromatography (HPLC) of polynuclear aromatics (PNA's) having more than four rings; (b) capillary gas chromatography (GC) of low molecular weight volatile PNA's; and (c) gas chromatography-mass spectrometry (GC-MS) for complementary identification of PNA's having functional and heterocyclic modifications.
A total of 41 PNA's were identified. Identification of 28 PNA's in the coal derived water (No. 3) was attained, whereas that of the true in-situ retort water (Omega-9) and the simulated retort water (No. 16) were 24 and 18, respectively. Thirteen PNA's were found to be common to all three wastewater samples. Thirteen PNA's were exclusively found in sample No. 3 whereas that of samples Omega-9 and No. 16 were 8 and 4, respectively. It was estimated that the concentration of PNA's in all samples ranged from traces to 30.0 ppb. 相似文献
A total of 41 PNA's were identified. Identification of 28 PNA's in the coal derived water (No. 3) was attained, whereas that of the true in-situ retort water (Omega-9) and the simulated retort water (No. 16) were 24 and 18, respectively. Thirteen PNA's were found to be common to all three wastewater samples. Thirteen PNA's were exclusively found in sample No. 3 whereas that of samples Omega-9 and No. 16 were 8 and 4, respectively. It was estimated that the concentration of PNA's in all samples ranged from traces to 30.0 ppb. 相似文献