327 research outputs found
Computer Simulation of PMSM Motor with Five Phase Inverter Control using Signal Processing Techniques
The signal processing techniques and computer simulation play an important role in the fault diagnosis and tolerance of all types of machines in the first step of design. Permanent magnet synchronous motor (PMSM) and five phase inverter with sine wave pulse width modulation (SPWM) strategy is developed. The PMSM speed is controlled by vector control. In this work, a fault tolerant control (FTC) system in the PMSM using wavelet switching is introduced. The feature extraction property of wavelet analysis used the error as obtained by the wavelet de-noised signal as input to the mechanism unit to decide the healthy system. The diagnosis algorithm, which depends on both wavelet and vector control to generate PWM as current based manage any parameter variation. An open-end phase PMSM has a larger range of speed regulation than normal PMSM. Simulation results confirm the validity and effectiveness of the switching strategy
Bisphenol A and Bisphenol S Induce Endocrine and Chromosomal Alterations in Brown Trout
Bisphenol A is a widely used compound found in large amount of consumer products. As concerns have been raised about its toxicological and public health effect, the use of alternatives to bisphenol A are now increasing. Bisphenol S is one of the analogues being used as a replacement for bisphenol A despite the fact that little is known about the effects of bisphenol S on living organisms. In this study, we investigated the potential endocrine and genotoxic effects of bisphenol A and bisphenol S in juvenile brown trout (Salmo trutta). The fish were exposed to the compounds for either 2 weeks or 8 weeks via sustained-release cholesterol implants containing doses of 2 mg/kg fish or 20 mg/kg fish of the substances. The effects on the thyroid hormone levels and the estrogenic disrupting marker vitellogenin were evaluated, along with the genotoxic markers micronucleated cells and erythrocyte nuclear abnormalities. An increase in plasma vitellogenin was observed in fish exposed to the high dose of bisphenol A for 2 weeks. At this experimental time the level of the thyroid hormone triiodothyronine (T3) in plasma was elevated after bisphenol S exposure at the high concentration, and paralleled by an increase of micronucleated cells. Moreover, bisphenol A induced an increase of micronuclei frequency in fish erythrocytes after the exposure at the lowest dose tested. Taken together the results indicate that both bisphenol A and its alternative bisphenol S cause endocrine disrupting and genotoxic effects in brown trout, although suggesting two different mechanisms of damage underlying bisphenol A and bisphenol S activity
A gene to organism approach--assessing the impact of environmental pollution in eelpout (Zoarces viviparus) females and larvae
A broad biomarker approach was applied to study the effects of marine pollution along the Swedish west coast using the teleost eelpout (Zoarces viviparus) as the sentinel species. Measurements were performed on different biological levels, from the molecular to the organismal, including measurements of messenger RNA (mRNA), proteins, cellular and tissue changes, and reproductive success. Results revealed that eelpout captured in Stenungsund had significantly higher hepatic ethoxyresorufin O-deethylase activity, high levels of both cytochrome P4501A and diablo homolog mRNA, and high prevalence of dead larvae and nuclear damage in erythrocytes. Eelpout collected in Göteborg harbor displayed extensive macrovesicular steatosis, whereby the majority of hepatocytes were affected throughout the liver, which could indicate an effect on lipid metabolism. Results also indicate that eelpouts collected at polluted sites might have an affected immune system, with lower mRNA expression of genes involved in the innate immune system and a higher number of lymphocytes. Biomarker assessment also was performed on livers dissected from unborn eelpout larvae collected from the ovary of the females. No significant differences were noted, which might indicate that the larvae to some extent are protected from effects of environmental pollutants. In conclusion, usage of the selected set of biological markers, covering responses from gene to organism, has demonstrated site-specific biomarker patterns that provided a broad and comprehensive picture of the impact of environmental stressors
Care leavers’ transition into the labour market in England
This is the final version. Available from the Nuffield Foundation and the Rees Centre via the links in this recordNuffield Foundatio
Evaluation of the Universal Screening Strategy in Qatar for the Management of Pregnant Women Carrying Group B Streptococci
Group B Streptococcus infection (GBS) has emerged as a serious disease, infecting 18,000 people in the United States annually including life-threatening illness in about 8,000 newly-born infants. To evaluate the efficiency of the current universal screening strategy for the management of GBS carriers a retrospective analysis was made of the records of 1,620 pregnant women in Qatar, 550 of whom were found to be carriers. These latter were then used as a group to be compared with 450 uninfected pregnant women in terms of nationality, parity, age, treatment, and outcome. Young and nullipara pregnant women had a high incidence of GBS but there was no significant effect on birth mortality and morbidity regardless of whether or not they received treatment with antibiotics. It is suggested that the cost of screening for GBS at the 35 th week of gestation cannot be justified.qscienc
The Role of the Mucus Barrier in Digestion
Mucus forms a protective layer across a variety of epithelial surfaces. In the gastrointestinal (GI) tract, the barrier has to permit the uptake of nutrients, while excluding potential hazards, such as pathogenic bacteria. In this short review article, we look at recent literature on the structure, location, and properties of the mammalian intestinal secreted mucins and the mucus layer they form over a wide range of length scales. In particular, we look at the structure of the gel-forming glycoprotein MUC2, the primary intestinal secreted mucin, and the influence this has on the properties of the mucus layer. We show that, even at the level of the protein backbone, MUC2 is highly heterogeneous and that this is reflected in the networks it forms. It is evident that a combination of charge and pore size determines what can diffuse through the layer to the underlying gut epithelium. This information is important for the targeted delivery of bioactive molecules, including nutrients and pharmaceuticals, and for understanding how GI health is maintained
Carotenoids Play a Positive Role in the Degradation of Heterocycles by Sphingobium yanoikuyae
BACKGROUND: Microbial oxidative degradation is a potential way of removing pollutants such as heterocycles from the environment. During this process, reactive oxygen species or other oxidants are inevitably produced, and may cause damage to DNA, proteins, and membranes, thereby decreasing the degradation rate. Carotenoids can serve as membrane-integrated antioxidants, protecting cells from oxidative stress. FINDINGS: Several genes involved in the carotenoid biosynthetic pathway were cloned and characterized from a carbazole-degrading bacterium Sphingobium yanoikuyae XLDN2-5. In addition, a yellow-pigmented carotenoid synthesized by strain XLDN2-5 was identified as zeaxanthin that was synthesized from β-carotene through β-cryptoxanthin. The amounts of zeaxanthin and hydrogen peroxide produced were significantly and simultaneously enhanced during the biodegradation of heterocycles (carbazole < carbazole + benzothiophene < carbazole + dibenzothiophene). These higher production levels were consistent with the transcriptional increase of the gene encoding phytoene desaturase, one of the key enzymes for carotenoid biosynthesis. CONCLUSIONS/SIGNIFICANCE: Sphingobium yanoikuyae XLDN2-5 can enhance the synthesis of zeaxanthin, one of the carotenoids, which may modulate membrane fluidity and defense against intracellular oxidative stress. To our knowledge, this is the first report on the positive role of carotenoids in the biodegradation of heterocycles, while elucidating the carotenoid biosynthetic pathway in the Sphingobium genus
Impact of Atherosclerosis- and Diabetes-Related Dicarbonyls on Vascular Endothelial Permeability: A Comparative Assessment
Background. Malondialdehyde (MDA), glyoxal (GO), and methylglyoxal (MGO) levels increase in atherosclerosis and diabetes patients. Recent reports demonstrate that GO and MGO cause vascular endothelial barrier dysfunction whereas no evidence is available for MDA. Methods. To compare the effects of MDA, GO, or MGO on endothelial permeability, we used human EA.hy926 endothelial cells as a standard model. To study cortical cytoplasm motility and cytoskeletal organization in endothelial cells, we utilized time-lapse microscopy and fluorescent microscopy. To compare dicarbonyl-modified protein band profiles in these cells, we applied Western blotting with antibodies against MDA- or MGO-labelled proteins. Results. MDA (150–250 μM) irreversibly suppressed the endothelial cell barrier, reduced lamellipodial activity, and prevented intercellular contact formation. The motile deficiency of MDA-challenged cells was accompanied by alterations in microtubule and microfilament organization. These detrimental effects were not observed after GO or MGO (250 μM) administration regardless of confirmed modification of cellular proteins by MGO. Conclusions. Our comparative study demonstrates that MDA is more damaging to the endothelial barrier than GO or MGO. Considering that MDA endogenous levels exceed those of GO or MGO and tend to increase further during lipoperoxidation, it appears important to reduce oxidative stress and, in particular, MDA levels in order to prevent sustained vascular hyperpermeability in atherosclerosis and diabetes patients
Combination of p53AIP1 and survivin expression is a powerful prognostic marker in non-small cell lung cancer
<p>Abstract</p> <p>Background</p> <p>p53AIP1 is a potential mediator of apoptosis depending on p53, which is mutated in many kinds of carcinoma. High survivin expression in non-small cell lung cancer is related with poor prognosis. To investigate the role of these genes in non-small cell lung cancer, we compared the relationship between p53AIP1 or survivin gene expression and the clinicopathological status of lung cancer.</p> <p>Materials and methods</p> <p>Forty-seven samples from non-small cell lung cancer patients were obtained between 1997 and 2003. For quantitative evaluation of RNA expression by PCR, we used Taqman PCR methods.</p> <p>Results</p> <p>Although no correlation between p53AIP1 or survivin gene expression and clinicopathological factors was found, the relationship between survivin gene expression and nodal status was significant (p = 0.03). Overall survival in the p53AIP1-negative group was significantly worse than in the positive group (p = 0.04); however, although survivin expression was not a prognostic factor, the combination of p53AIP1 and survivin was a significant prognostic predictor (p = 0.04). In the multivariate cox proportional hazard model, the combination was an independent predictor of overall survival (p53AIP1 (+) survivin (+), HR 0.21, 95%CI = [0.01–1.66]; p53AIP1 (+) survivin (-), HR 0.01, 95%CI = [0.002–0.28]; p53AIP1 (-) survivin (-), HR 0.01, 95%CI = [0.002–3.1], against p53AIP1 (-) survivin (+), p = 0.03).</p> <p>Conclusion</p> <p>These data suggest that the combination of p53AIP1 and survivin gene expression may be a powerful tool to stratify subgroups with better or worse prognosis from the variable non-small cell lung cancer population.</p
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