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排序方式: 共有713条查询结果,搜索用时 31 毫秒
61.
JD Kaufman MA Cohen SR Sama JW Shields J Kalat 《Canadian Metallurgical Quarterly》1998,88(7):1047-1051
OBJECTIVES: This study sought to characterize occupational dermatoses and cutaneous hazards. METHODS: Workers' compensation claims filed for skin disease in the Washington State Fund were analyzed for 1989 through 1993; incidence rates for industries and employers were calculated, and cutaneous hazards associated with the highest rates were identified. RESULTS: A total of 7445 claims were filed for skin disorders, principally contact dermatitis; 675 (9.1%) involved more than 3 missed work-days. The rate of accepted skin disorder claims was 1.0 per 1000 full-time employee-years. The highest incidence rates (4.6 to 30.7 accepted claims per 1000 full-time employee-years) were in certain manufacturing industries (plastics related, concrete products, aircraft parts, sporting goods, and boat building), wholesale farm product raw materials, automotive glass replacement, and beauty shops. Seven of the 10 employers with the highest incidence rates (19.6 to 85.5 accepted claims per 1000 full-time employee-years) used fiber-reinforced plastics (composites) and exposed workers to epoxy and other resin systems associated with contact dermatitis. CONCLUSIONS: Workers' compensation data identify known and emerging workplace cutaneous hazards and show promise for targeting prevention efforts. 相似文献
62.
Glutamate is an important excitatory signal in the hypothalamus for the steroid-mediated preovulatory gonadotropin surge. Steroids may exert this action by regulating glutamate receptor levels or glutamate release, or both. Work in our laboratory found no changes in NMDA and kainate receptor binding in the hypothalamus of castrated or castrated plus steroid-replaced male and female rats. Likewise, we found that NMDA and kainate binding did not change over the onset of puberty in the female rat. A competitive quantitative RT-PCR assay using exogenous internal standards was used to measure NMDAR1, GluR1, and beta-actin mRNAs levels. NMDAR1 and GluR1 expression was examined in the preoptic hypothalamic area and in the medial basal hypothalamus at Postnatal Days 10, 15, 20, 25, 30, 32, 34, 36, 40, and 63. A transient increase in GluR1 mRNA levels in the preoptic hypothalamic area was observed on Day 20, with all other time points showing comparable levels. NMDAR1 levels in the POA and medial basal hypothalamus did not change significantly at any of the time points; in contrast, however, AMPA receptor binding levels were increased in the hypothalamus at the time of puberty in the female rat. Thus, in addition to the previously reported elevation of glutamate release rates in the hypothalamus at the time of puberty, AMPA receptors may also be elevated and play a role in mediating glutamate regulatory effects on the timing of puberty in the female rat. 相似文献
63.
GA Smith SD Strausbaugh C Harbeck-Weber DM Cohen BJ Shields JD Powers 《Canadian Metallurgical Quarterly》1998,37(7):405-412
When a rigorous methodological approach is utilized, a substantial majority of recent studies provide evidence for the familial transmission of schizophrenia. Although the absolute rates of schizophrenia among relatives of schizophrenics tend to be lower than those reported in the earlier studies due to the restrictiveness of contemporary definitions of schizophrenia, the risk to relatives compared to that of controls has remained quite consistent. This observation that relatives of schizophrenics have an elevated risk for schizophrenia compared to controls is consistent with theories of both genetic and environmental transmission. Twin studies of schizophrenia have consistently reported greater concordance rates for monozygotic than dizygotic twins. Although this indicates the importance of genetic factors, the less than 100% concordance for monozygotic twins observed in every study indicates that nongenetic factors also play a role in the etiology of schizophrenia. Further, adoption studies offer an opportunity to unconfound genes and environment. The findings of adoption studies confirm that there are genetic components for schizophrenia. Even though we have shown that family, twin, and adoption studies have provided strong evidence for the role of genetic factors in schizophrenia, the mode of transmission remains unclear. The results of mathematical modeling studies do not support the single gene model. There is somewhat more support for the multifactorial polygenic model, but the model has also been rejected in several studies. Thus, the pattern of inheritance of schizophrenia has eluded an unambiguous characterization. Genetic linkage analysis promised to clarify the mechanisms of transmission, but early positive reports were subsequently overturned and, to date, there are no consistently replicated positive linkage findings for schizophrenia. There is now a world-wide search for the location of the genes on specific chromosomes which are responsible for schizophrenia. The clinical implications of current work to the future of locating a schizophrenic gene or genes will be discussed. 相似文献
64.
Shields H. Fornaca S.W. Petach M.B. Orsini R.A. Moyer R.H. St Pierre R.J. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2002,90(10):1689-1695
Pulsed Nd:YAG lasers have been developed to achieve high peak power and high pulse repetition rate. These systems are being used as drivers for laser-produced plasmas which efficiently convert the 1064-nm laser output to extreme ultraviolet (EUV) light at 13.5 nm for future microlithography systems. The requirements for laser-produced plasma EUV light sources and their integration in lithography tools for high-volume manufacturing are reviewed to establish the key design issues for high-power lasers and plasma targets. Xenon has been identified as a leading target material to realize the goals of intense EUV emission and clean operation. Recent progress in high-power diode-pumped Nd:YAG lasers and xenon targets for EUV generation is reviewed, showing that laser-produced plasma sources meet the needs for current EUV lithography development tools. Future directions to meet EUV source requirements for high-volume manufacturing tools are discussed. 相似文献
65.
Previous studies in rodents have reported that clonidine, an alpha 2-adrenergic receptor agonist, attenuated conditioned aversions to naloxone-precipitated opiate withdrawal when administered prior to each withdrawal conditioning episode. The current study was designed to determine whether clonidine could modify the expression of previously established conditioned place aversions and conditioned suppression of operant responding. Dose- and time-dependent effects of clonidine on activity and suppression of operant responding for food identified appropriate treatment parameters for subsequent studies in which rats rendered dependent on opiates through implantation of morphine pellets were tested for: (1) conditioned place aversion; and (2) conditioned suppression of operant responding for food (fixed ratio-15 schedule), in a paradigm wherein rats received four pairings of naloxone with a distinct tone and odor stimulus. Clonidine dose-dependently blocked the acquisition of both conditioned behaviors when administered prior to naloxone on each conditioning trial, but was ineffective in blocking the expression of these conditioned withdrawal signs when administered prior to the test session. 相似文献
66.
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68.
Understanding the retention time of water in waterbodies during periods of no surface flow in dryland rivers provides an important context for evaluating the ecological importance of a waterhole to the river system. Time series of water level data were collected from 10 waterbodies spread across three river systems of the Lake Eyre Basin (LBE), Australia. Observed loss rates in the absence of surface flow were compared to modelled evaporation rates in order to determine whether open water evaporation was the main loss process from isolated waterholes and to what extent there is evidence of interaction between the surface water and any shallow groundwater aquifers. The modelled evaporation rates were determined using the Penman combination equation and meteorological data from the closest climate station in the region of the waterbodies. The modelled evaporation data were able to explain only some of the variability in the observed loss data but did highlight periods where other processes (including observation error) need to be invoked. These other possible processes, which include temporary groundwater connection and the effect of heat storage on the evaporation losses, probably contribute as much to the observed data variability as error introduced by the use of regional meteorological data. Assuming evaporation is the dominant process determining water loss in the absence of flow, the persistence of a waterhole is primarily dependent upon its depth when flow ceases. The annual loss shown by most waterbodies lies within the range of the modelled evaporation rate using the Penman combination equation and equates between 1.5 and 2.5 m per annum. The use of water level data in conjunction with the modelled evaporation rates was able to provide important insights into controls on waterbody loss rates and persistence. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
69.
AD Anichkov AV Vodianov SV Mozhaev TN Trofimova VB Nizkovolos AV Obliapin IuZ Polonski? AL Spirin 《Canadian Metallurgical Quarterly》1998,(3):6-9; discussion 9-10
The paper summarizes experience with stereotactic operations by magnetic resonance imaging data by using a Russian OREOL stereotactic manipulator. It describes methods of preoperative preparation of patients by employing diagnostic magnetic resonance tomographs. A number of points of the procedure for identification and localization of deep target structures from magnetic resonance images in parkinsonism, temporal epilepsy and some mental disorders. 相似文献
70.
VB de Carvalho EF Sousa JH Vila JP da Silva MR Caiado SR Araujo R Macruz EJ Zerbini 《Canadian Metallurgical Quarterly》1996,94(8):1815-1817
BACKGROUND: Heart transplantation (HT) as a therapeutic option for end-stage chronic Chagas' heart disease (CCHD) is controversial. Reactivation of Trypanosoma cruzi infection and recurrence of the disease in the allograft are likely to occur. Furthermore, active myocarditis has been reported to predispose patients to an increased incidence and severity of rejection. METHODS AND RESULTS: We prospectively investigated the long-term follow-up of 10 patients with CCHD who underwent HT. Immunosuppression was based on cyclosporine A and azathioprine. T cruzi reactivation was prevented with benzonidazole. Besides allograft rejection surveillance, T cruzi infection was monitored through blood tests, myocardial biopsies, and serological tests. Over a mean follow-up period of 34 +/- 38 months (range, 73 to 124 months), 7 patients are alive and in NYHA functional class I. Life expectancy was 78% for the second year and 65% for 10 years. Rejection was less frequent in chagasic than in age- and sex-matched control patients (mean +/- SD, 1.60 +/- 1.26 versus 5.70 +/- 1.89 episodes per patient, respectively; P = .0001); decreased severity of rejection was also observed (P = .006). T cruzi parasitemias detected on three occasions were successfully treated with benzonidazole. There were no signs of recurrence of the disease in the allograft. CONCLUSIONS: These results suggest an important role of HT in the treatment of CCHD. There was a low frequency of T cruzi infection reactivation and no signs of recurrence of the disease in the allograft. The surprisingly decreased rejection incidence and severity require further studies for elucidation. 相似文献