990 resultados para Toxicological effects


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This study examined the efficacy of a participatory ergonomics intervention in preventing musculoskeletal disorders (MSDs) and changing unsatisfactory psychosocial working conditions among municipal kitchen workers. The occurrence of multiple-site musculoskeletal pain (MSP) and associations between MSP and psychosocial factors at work over time were studied secondarily. A cluster randomized controlled trial was conducted during 2002-2005 in 119 municipal kitchens with 504 workers. The kitchens were randomized to an intervention (n = 59) and control (n = 60) group. The intervention lasted 11 to 14 months. The workers identified strenuous work tasks and sought solutions for decreasing physical and mental workload. The main outcomes were the occurrence of and trouble caused by musculoskeletal pain in seven anatomical sites, local musculoskeletal fatigue after work, and musculoskeletal sick leaves. Psychosocial factors at work (job control, skill discretion, co-worker relationships, supervisor support, mental strenuousness of work, hurry, job satisfaction) and mental stress were studied as intermediate outcomes of the intervention. Questionnaire data were collected at three months intervals during the intervention and the one-year post-intervention follow-up. Response rates varied between 92 % and 99 %. In total, 402 ergonomic changes were implemented. In the control group, 80 changes were spontaneously implemented within normal activity. The intervention did not reduce perceived physical workload and no systematic differences in any health outcomes were found between the intervention and control groups during the intervention or during the one-year follow-up. The results suggest that the intervention as studied in the present trial was not more effective in reducing perceived physical workload or preventing MSDs compared with no such intervention. Little previous evidence of the effectiveness of ergonomics interventions in preventing MSDs exists. The effects on psychosocial factors at work were adverse, especially in the two of the participating cities where re-organization of foodservices timed simultaneously with the intervention. If organizational reforms at workplace are expected to occur, the execution of other workplace interventions at the same time should be avoided. The co-occurrence of musculoskeletal pain at several sites is observed to be more common than pain at single anatomical sites. However, the risk factors of MSP are largely unknown. This study showed that at baseline, 73 % of the women reported pain in at least two, 36 % in four or more, and 10 % in six to seven sites. The seven pain symptoms occurred in over 80 different combinations. When co-occurrence of pain was studied in three larger anatomical areas (neck/low back, upper limbs, lower limbs), concurrent pain in all three areas was the most common combination (36 %). The 3-month prevalence of MSP (≥ 3 of seven sites) varied between 50 % and 61 % during the two-year follow-up period. Psychosocial factors at work and mental stress were strong predictors for MSP over time and, vice versa, MSP predicted psychosocial factors at work and mental stress. The reciprocality of the relationships implies either two mutually dependent processes in time, or some shared common underlying factor(s).

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Quantifying surfactant interaction effects on soil moisture and turf quality.

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This project aims to determine plant growth response to water treated with the Silverwater disinfestation system against plants that have been irrigated with non treated water. The trial will monitor and measure plant growth rates and health to identify any variations that can be attributed to the Silverwater Technologies disinfestation unit.

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In this paper, for the first time, the effects of energy quantization on single electron transistor (SET) inverter performance are analyzed through analytical modeling and Monte Carlo simulations. It is shown that energy quantization mainly changes the Coulomb blockade region and drain current of SET devices and thus affects the noise margin, power dissipation, and the propagation delay of SET inverter. A new analytical model for the noise margin of SET inverter is proposed which includes the energy quantization effects. Using the noise margin as a metric, the robustness of SET inverter is studied against the effects of energy quantization. A compact expression is developed for a novel parameter quantization threshold which is introduced for the first time in this paper. Quantization threshold explicitly defines the maximum energy quantization that an SET inverter logic circuit can withstand before its noise margin falls below a specified tolerance level. It is found that SET inverter designed with CT:CG=1/3 (where CT and CG are tunnel junction and gate capacitances, respectively) offers maximum robustness against energy quantization.

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This project investigates the impact of vegetable production systems on sensitive waterways focusing on the risk of off-site nutrient movement at farm block scale under current management practices. The project establishes a series of case studies in two environmentally important Queensland catchments and conducts a broader survey of partial nutrient budgets across tropical vegetable production. It will deliver tools to growers that can improve fertiliser use efficiency delivering profitability and environmental improvements.

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Serum butyrylcholinesterase (BCHE) activity is associated with obesity, blood pressure and biomarkers of cardiovascular and diabetes risk. We have conducted a genome-wide association scan to discover genetic variants affecting BCHE activity, and to clarify whether the associations between BCHE activity and cardiometabolic risk factors are caused by variation in BCHE or whether BCHE variation is secondary to the metabolic abnormalities. We measured serum BCHE in adolescents and adults from three cohorts of Australian twin and family studies. The genotypes from approximately 2.4 million single-nucleotide polymorphisms (SNPs) were available in 8791 participants with BCHE measurements. We detected significant associations with BCHE activity at three independent groups of SNPs at the BCHE locus (P = 5.8 x 10(-262), 7.8 x 10(-47), 2.9 x 10(-12)) and at four other loci: RNPEP (P = 9.4 x 10(-16)), RAPH1-ABI2 (P = 4.1 x 10(-18)), UGT1A1 (P = 4.0 x 10(-8)) and an intergenic region on chromosome 8 (P = 1.4 x 10(-8)). These loci affecting BCHE activity were not associated with metabolic risk factors. On the other hand, SNPs in genes previously associated with metabolic risk had effects on BCHE activity more often than can be explained by chance. In particular, SNPs within FTO and GCKR were associated with BCHE activity, but their effects were partly mediated by body mass index and triglycerides, respectively. We conclude that variation in BCHE activity is due to multiple variants across the spectrum from uncommon/large effect to common/small effect, and partly results from (rather than causes) metabolic abnormalities.

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The photochemistry and photophysics of organic molecules in organized assemblies are being studied with great interest in order to understand the features controlling the selectivity in the photoreactions brought about by these media.l These studies have paved the way to an intriguing number of possibilities by which photoreactivity can be modified. In this connection, we have investigated the photobehavior of a number of phenyl alkyl ketones and cu,cu-dimethylphenyl alkyl ketones (Scheme I) incorporated in the hydrophobic interior of cyclodextrin cavities.

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The impact of erroneous genotypes having passed standard quality control (QC) can be severe in genome-wide association studies, genotype imputation, and estimation of heritability and prediction of genetic risk based on single nucleotide polymorphisms (SNP). To detect such genotyping errors, a simple two-locus QC method, based on the difference in test statistic of association between single SNPs and pairs of SNPs, was developed and applied. The proposed approach could detect many problematic SNPs with statistical significance even when standard single SNP QC analyses fail to detect them in real data. Depending on the data set used, the number of erroneous SNPs that were not filtered out by standard single SNP QC but detected by the proposed approach varied from a few hundred to thousands. Using simulated data, it was shown that the proposed method was powerful and performed better than other tested existing methods. The power of the proposed approach to detect erroneous genotypes was approximately 80% for a 3% error rate per SNP. This novel QC approach is easy to implement and computationally efficient, and can lead to a better quality of genotypes for subsequent genotype-phenotype investigations.

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An investigation of the problem of controlled doping of amorphous chalcogenide semiconductors utilizing a Bridgman anvil high pressure technique, has been undertaken. Bulk amorphous semiconducting materials (GeSe3.5)100-x doped with M = Bi (x = 2, 4, 10) and M = Sb (x = 10) respectively are studied up to a pressure of 100 kbar down to liquid nitrogen temperature, with a view to observe the impurity induced modifications. Measurement of the electrical conductivity of the doped samples under quasi-hydrostatic pressure reveals that the pressure induced effects in lightly doped (2 at % Bi) and heavily doped (x = 4, 10) semiconductors are markedly different. The pressure effects in Sb-doped semiconductors are quite different from those in Bi-doped material.

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Knowledge of cattle tick (Rhipicephalus (Boophilus) microplus; Acari: Ixodidae) molecular and cellular pathways has been hampered by the lack of an annotated genome. In addition, most of the tick expressed sequence tags (ESTs) available to date consist of similar to 50% unassigned sequences without predicted functions. The most common approach to address this has been the application of RNA interference (RNAi) methods to investigate genes and their pathways. This approach has been widely adopted in tick research despite minimal knowledge of the tick RNAi pathway and double-stranded RNA (dsRNA) uptake mechanisms. A strong knockdown phenotype of adult female ticks had previously been observed using a 594 bp dsRNA targeting the cattle tick homologue for the Drosophila Ubiquitin-63E gene leading to nil or deformed eggs. A NimbleGen cattle tick custom microarray based on the BmiGI.V2 database of R. microplus ESTs was used to evaluate the expression of mRNAs harvested from ticks treated with the tick Ubiquitin-63E 594 bp dsRNA compared with controls. A total of 144 ESTs including TC6372 (Ubiquitin-63E) were down-regulated with 136 ESTs up-regulated following treatment. The results obtained substantiated the knockdown phenotype with ESTs identified as being associated with ubiquitin proteolysis as well as oogenesis, embryogenesis, fatty acid synthesis and stress responses. A bioinformatics analysis was undertaken to predict off-target effects (OTE) resulting from the in silico dicing of the 594 bp Ubiquitin-63E dsRNA which identified 10 down-regulated ESTs (including TC6372) within the list of differentially expressed probes on the microarrays. Subsequent knockdown experiments utilising 196 and 109 bp dsRNAs, and a cocktail of short hairpin RNAs (shRNA) targeting Ubiquitin-63E, demonstrated similar phenotypes for the dsRNAs but nil effect following shRNA treatment. Quantitative reverse transcriptase PCR analysis confirmed differential expression of TC6372 and selected ESTs. Our study demonstrated the minimisation of predicted OTEs in the shorter dsRNA treatments (similar to 100-200 bp) and the usefulness of microarrays to study knockdown phenotypes.

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Telomere length has been purported as a biomarker for age and could offer a non-lethal method for determining the age of wild-caught individuals. Molluscs, including oysters and abalone, are the basis of important fisheries globally and have been problematic to accurately age. To determine whether telomere length could provide an alternative means of ageing molluscs, we evaluated the relationship between telomere length and age using the commercially important Sydney rock oyster (Saccostrea glomerata). Telomere lengths were estimated from tissues of known age individuals from different age classes, locations and at different sampling times. Telomere length tended to decrease with age only in young oysters less than 18 months old, but no decrease was observed in older oysters aged 2-4 years. Regional and temporal differences in telomere attrition rates were also observed. The relationship between telomere length and age was weak, however, with individuals of identical age varying significantly in their telomere length making it an imprecise age biomarker in oysters.