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J Ali EB Freyfogle RJ Parker RM Bell C Maimaris BE Krantz IS Hughes 《Canadian Metallurgical Quarterly》1997,163(7):483-486
OBJECTIVES: To determine whether blurred vision caused by exposure to triethylamine (TEA) can be detected by the measurement of contrast sensitivity. METHODS: 41 cold box core makers of three foundries and 82 control workers were examined. A detailed ocular and medical history was obtained from the subjects. The contrast sensitivity of the core makers was measured on Monday and Friday of the same week both before and immediately after work and also on a third day, when air samples of TEA were collected. Contrast sensitivity and visual acuity were measured by optotype figures at full contrast, 2.5% contrast, and 0.6% contrast. The changes in contrast sensitivity were used for the analysis. The results of binocular vision and the results of the dominant eye were analysed. Urine specimens for the analysis of TEA were collected on every occasion when contrast sensitivity was measured. RESULTS: 78% of the core makers had had symptoms of blurred vision, and 31% had had trouble driving or working. The breathing zone eight hour time weighted average TEA concentrations were 0.3-60 mg/m3. The mean urinary TEA concentration after the shift was 35 mmol/mol creatinine. Continuous monitoring showed high peaks of TEA leakage at a core making machine. Changes in binocular visual acuity did not differ between the exposed and unexposed workers. The contrast sensitivity decreased in 49% of the core makers and 21% of the controls (P = 0.002). CONCLUSIONS: The blurred vision caused by exposure to TEA can be documented by measuring contrast sensitivity. The mechanism by which TEA produces symptoms remains an issue of further study. 相似文献
83.
Maisto Stephen A.; Pollock Nancy Kaczynski; Lynch Kevin G.; Martin Christopher S.; Ammerman Robert 《Canadian Metallurgical Quarterly》2001,15(1):68
Clinical course was studied in 131 male and female adolescents with current alcohol use disorder (AUD) at baseline (BL). Participants were classified into 4 groups according to their diagnosis and drinking pattern 1 year later. The 4 groups were compared with each other and with 37 community control participants. Results showed that over half of the clinical sample no longer had a current AUD at 1 year; about 64% were and 36% were not still drinking. BL discriminators of 1-year status were alcohol dependence, other drug use, and coping. All of the clinical groups tended to show improvement at 1 year in the main dependent variables, and the abstainers' level of drug use and coping were comparable with that of the community participants. These findings suggest that many adolescents improve in functioning during the 1 year after alcohol and drug treatment and that a stress and coping model is useful for studying clinical course of AUDs in adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
84.
D Reddy AS Pollock SA Clark K Sooy RC Vasavada AF Stewart T Honeyman S Christakos 《Canadian Metallurgical Quarterly》1997,94(5):1961-1966
85.
Describes a balanced pinFET receiver which employs two signal amplification paths for homodyne detection of multigigabit-per-second, pilot-carrier PSK optical signals. Using narrow-line 1.51 mu m semiconductor lasers, the authors have employed this receiver to phaselock a local oscillator to a 295 pW pilot carrier with 8 degrees RMS phase error.<> 相似文献
86.
The effects of fibre/matrix interface strength and thermal residual stresses on the mechanical properties of a silicon carbide/titanium composite were investigated. A 3-ply [0/90/0] composite was subjected to a simulated superplastic forming/diffusion bonding (SPF/DB) temperature cycle which changed fibre/matrix interfacial strength and thermal residual stresses in the composite. The [0/90/0] composite subjected to the SPF/DB process showed a 25% decrease in ultimate tensile strength (UTS) and a 30% decrease in failure strain compared to the as-fabricated (ASF) material. The fatigue life for the SPF/DB specimens was approximately 50% lower than the ASF specimens. The fracture surface of the ASF specimens was very irregular accompanied by substantial fibre pull-out as compared to the planar fracture surface of the SPF/DB cycled specimens that showed negligible fibre pull-out. The large changes in the tensile strength and fatigue life due to the SPF/DB cycle are explained by a difference in the failure mechanisms occurring as a result of the SPF/DB-induced changes in the strength of the fibre/matrix interface and higher thermal residual stresses. Unreinforced titanium was also tested to study the effect of the SPF/DB cycle on the matrix static properties. Fibres were etched from the composite and then individually tested for modulus and strength. Finally, a microscopic examination of the fibre/matrix interface was performed to study the effects of the SPF/DB cycle on the interface. 相似文献
87.
LS Wafelman BH Pollock J Kreutzer DS Richards AA Hutchison 《Canadian Metallurgical Quarterly》1999,75(2):73-81
Prognostic factors for survival of 62 fetuses and neonates with nonimmune hydrops fetalis (NIHF) were studied retrospectively. Twenty-eight infants survived >/=28 days which is 45% for all fetuses and newborns diagnosed with NIHF and 61% for liveborns with unresolved NIHF. Univariate analysis identified that mortality was associated with the presence of >/=2 serous cavity effusions and a need for chest compressions at birth. Multivariate logistic regression analysis confirmed that the presence of >/=2 serous cavity effusions was significantly associated with mortality from NIHF <28 days after birth [OR = 48.2 (CI 3.6, 662.9) (p < 0.004)]. We conclude that, compared to published cases from the 1970s and early 1980s, survival of liveborns with NIHF seems improved. The decrease in stillbirths is more notable. The severity of hydrops at birth is the key determinant for survival. 相似文献
88.
Lymphocytes of a New World primate, the cotton-top tamarin (Saguinus oedipus), express classical G-related major histocompatibility complex (MHC) class I molecules with unusually limited polymorphism and variability. Three G-related loci, an F locus, an E locus, and two pseudogenes (So-N1 and So-N3) have been identified by cDNA library screening and extensive PCR analysis of both cDNA and genomic DNA from the cotton-top tamarin. Furthermore, each genus of the subfamily Callitrichinae (tamarins and marmosets) appears to express its own unique set of MHC class I genes, likely due to a rapid turnover of loci. The rapid emergence of unique MHC class I genes in the Callitrichinae genera, resulting from an active process of duplication and inactivation of loci, may account for the limited diversity of the MHC class I genes in the cotton-top tamarin. To determine the nature of the entire complement of MHC class I genes in the cotton-top tamarin, we synthesized a genomic DNA library and screened it with MHC class I-specific probes. We isolated nine new MHC class I pseudogenes from this library. These newly isolated tamarin G-related MHC class I pseudogenes are not closely related to any of their functional counterparts in the tamarin, suggesting that they do not share a recent common ancestral gene with the tamarin's currently expressed MHC class I loci. In addition, these tamarin sequences display a high rate of nonsynonymous substitutions in their putative peptide binding region. This indicates that the genes from which they have derived were likely subject to positive selection and, therefore, were once functional. Our data support the notion that an extremely high rate of loci turnover is largely responsible for the limited diversity of the MHC class I genes in the cotton-top tamarin. 相似文献
89.
90.