1,041 research outputs found

    Feature extraction of arc tracking phenomenon

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    This document outlines arc tracking signals -- both the data acquisition and signal processing. The objective is to obtain the salient features of the arc tracking phenomenon. As part of the signal processing, the power spectral density is obtained and used in a MATLAB program

    Fault handling schemes in electronic systems with specific application to radiation tolerance and VLSI design

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    Naturally occurring space radiation particles can produce transient and permanent changes in the electrical properties of electronic devices and systems. In this work, the transient radiation effects on DRAM and CMOS SRAM were considered. In addition, the effect of total ionizing dose radiation of the switching times of CMOS logic gates were investigated. Effects of transient radiation on the column and cell of MOS dynamic memory cell was simulated using SPICE. It was found that the critical charge of the bitline was higher than that of the cell. In addition, the critical charge of the combined cell-bitline was found to be dependent on the gate voltage of the access transistor. In addition, the effect of total ionizing dose radiation on the switching times of CMOS logic gate was obtained. The results of this work indicate that, the rise time of CMOS logic gates increases, while the fall time decreases with an increase in total ionizing dose radiation. Also, by increasing the size of the P-channel transistor with respect to that of the N-channel transistor, the propagation delay of CMOS logic gate can be made to decrease with, or be independent of an increase in total ionizing dose radiation. Furthermore, a method was developed for replacing polysilicon feedback resistance of SRAMs with a switched capacitor network. A switched capacitor SRAM was implemented using MOS Technology. The critical change of the switched capacitor SRAM has a very large critical charge. The results of this work indicate that switched capacitor SRAM is a viable alternative to SRAM with polysilicon feedback resistance

    Transsulfuration pathway thiols and methylated arginines: the hunter community study

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    Background: Serum homocysteine, when studied singly, has been reported to be positively associated both with the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine [ADMA, via inhibition of dimethylarginine dimethylaminohydrolase (DDAH) activity] and with symmetric dimethylarginine (SDMA). We investigated combined associations between transsulfuration pathway thiols, including homocysteine, and serum ADMA and SDMA concentrations at population level. Methods: Data on clinical and demographic characteristics, medication exposure, C-reactive protein, serum ADMA and SDMA (LC-MS/MS), and thiols (homocysteine, cysteine, taurine, glutamylcysteine, total glutathione, and cysteinylglycine; capillary electrophoresis) were collected from a sample of the Hunter Community Study on human ageing [n = 498, median age (IQR) = 64 (60–70) years]. Results: Regression analysis showed that: a) age (P = 0.001), gender (P = 0.03), lower estimated glomerular filtration rate (eGFR, P = 0.08), body mass index (P = 0.008), treatment with beta-blockers (P = 0.03), homocysteine (P = 0.02), and glutamylcysteine (P = 0.003) were independently associated with higher ADMA concentrations; and b) age (P = 0.001), absence of diabetes (P = 0.001), lower body mass index (P = 0.01), lower eGFR (P&lt;0.001), cysteine (P = 0.007), and glutamylcysteine (P&lt;0.001) were independently associated with higher SDMA concentrations. No significant associations were observed between methylated arginines and either glutathione or taurine concentrations. Conclusions: After adjusting for clinical, demographic, biochemical, and pharmacological confounders the combined assessment of transsulfuration pathway thiols shows that glutamylcysteine has the strongest and positive independent associations with ADMA and SDMA. Whether this reflects a direct effect of glutamylcysteine on DDAH activity (for ADMA) and/or cationic amino acid transport requires further investigations.</br

    Clinical and biochemical correlates of serum L-ergothioneine concentrations in community-dwelling middle-aged and older adults

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    Background: Despite the increasing interest towards the biological role of L-ergothioneine, little is known about the serum concentrations of this unusual aminothiol in older adults. We addressed this issue in a representative sample of communitydwelling middle-aged and older adults. Methods: Body mass index, estimated glomerular filtration rate, serum concentrations of L-ergothioneine, taurine, homocysteine, cysteine, glutathione, cysteinylglycine, and glutamylcysteine were evaluated in 439 subjects (age 55–85 years) randomly selected from the Hunter Community Study. Results: Median L-ergothioneine concentration in the entire cohort was 1.01 IQR 0.78–1.33 mmol/L. Concentrations were not affected by gender (P = 0.41) or by presence of chronic medical conditions (P = 0.15). By considering only healthy subjects, we defined a reference interval for L-ergothioneine serum concentrations from 0.36 (90% CI 0.31–0.44) to 3.08 (90% CI 2.45–3.76) mmol/L. Using stepwise multiple linear regression analysis L-ergothioneine was negatively correlated with age (rpartial =20.15; P = 0.0018) and with glutamylcysteine concentrations (rpartial =20.13; P = 0.0063). Conclusions: A thorough analysis of serum L-ergothioneine concentrations was performed in a large group of communitydwelling middle-aged and older adults. Reference intervals were established. Age and glutamylcysteine were independently negatively associated with L-ergothioneine serum concentration.</br

    Patient reported frequency of lupus flare: associations with foundation makeup and sunscreen use

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    Objective: To test the hypothesis that usage of foundation makeup (FM) and sunscreen lotion (SS), used individually or in combination, is associated with significant changes in the likelihood of lupus symptom exacerbation. Methods: Self-reported flare days (SRF) and use of FM and SS products, were retrospectively examined in 80 Caucasian Australian women with ACR classified SLE for a year. Negative binomial regression modelled SRF days (outcome) against independent FMSS variable and covariates: age; diagnosis years; outdoor hours; BMI; stress; immune therapy medication (ITM) use. Results: Statistically significant inverse associations between SRF days and FMSS use were found. Protective effects were statistically significant (p < 0.05) for combined FMSS exposure days (OR 0.998, CI 0.997 - 1.0) and FM alone (OR 0.603, CI 0.363 - 1.0). Significant associations consistent with increased SRF risk were seen in sub-analysis models for participants taking ITM: univariate model (OR 1.968, p = 0.03); multivariate model for FMSS (OR 2.11, CI 1.161 - 3.835); FM days (OR 1.855, CI 1.023 - 3.364). Results show SRF day reduction of 0.15% for each day of product exposure. Conclusion: Study results highlight protective effects of wearing FM with or without SS. This reduction in flare days ultimately has potential to improve quality of life in SLE patients

    Engineering Standards: An Introduction for Electrical and Computer Engineering Students

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    Engineering standards are summaries of industrial best practices. The specifications are written in terms of functional, mechanical and electrical aspects that allow proper usage of available components to build a system. Standards may also be regarded as codified guidelines that define how tests should be performed, and how products are to be designed. Standards are created by bringing together experience and expertise of stakeholders on specific issues. Standards protect public health and safety, improve product quality, help to advance the growth of new technologies, and foster international trade. It is important that students get familiar with standards while in school

    Effects of study design and allocation on self-reported alcohol consumption: randomized trial.

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    BACKGROUND: What participants think about the nature of a study might affect their behaviour and bias findings. We tested two hypotheses: (1) participants told they were in an intervention trial would report lower alcohol consumption at follow-up than those told they were in a cohort study; (2) participants told they were in the intervention group in a trial would have lower alcohol consumption at follow-up than those told they were in the control group. METHODS: Students from four universities (N = 72,903) were invited to participate in a 'research project on student drinking'. Of 10,415 respondents, 6,788 were moderate to heavy drinkers and were randomized. Group A ('cohort') were informed their drinking would be assessed at baseline and again in one month. Group B ('control') were told the study was an intervention trial and they were in the control group. Group C ('intervention') were told the study was an intervention trial and they were to receive the intervention. All were assessed and directed to read identical online alcohol education material. Whether and how long they accessed the material were recorded. One month later, alcohol intake was reassessed. RESULTS: In relation to hypothesis 1, there were no differences between the groups on the prespecified outcome measures. In relation to hypothesis 2, there were no differences though all point estimates were in the hypothesized direction (that is, 'intervention' < 'control'). The 'cohort' and 'control' groups accessed the material to a similar extent (59% versus 57%) while the 'intervention' group were more likely to access it (78%) and to read it for longer (median 35 s (25th and 75th percentiles: 6, 97) versus medians of 7 s (0, 28) and 8 s (4, 42) for the 'cohort' and 'control' groups, respectively). CONCLUSIONS: Although the context given to the research participants significantly influenced access to the online information and reading time, this did not translate into any effect on drinking behaviour, for either hypothesis. This might be because of failure in the experimental paradigm or the possibility of weaker effects using the online approach. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000846022

    Short sleep duration is associated with risk of future diabetes but not cardiovascular disease: a prospective study and meta-analysis

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    Epidemiologic studies have observed association between short sleep duration and both cardiovascular disease (CVD) and type 2 diabetes, although these results may reflect confounding by pre-existing illness. This study aimed to determine whether short sleep duration predicts future CVD or type 2 diabetes after accounting for baseline health. Baseline data for 241,949 adults were collected through the 45 and Up Study, an Australian prospective cohort study, with health outcomes identified via electronic database linkage. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals. Compared to 7h sleep, <6h sleep was associated with incident CVD in participants reporting ill-health at baseline (HR=1.38 [95% CI: 1.12-1.70]), but not after excluding those with baseline illness and adjusting for baseline health status (1.03 [0.88-1.21]). In contrast, the risk of incident type 2 diabetes was significantly increased in those with <6h versus 7h sleep, even after excluding those with baseline illness and adjusting for baseline health (HR=1.29 [1.08-1.53], P=0.004). This suggests the association is valid and does not simply reflect confounding or reverse causation. Meta-analysis of ten prospective studies including 447,124 participants also confirmed an association between short sleep and incident diabetes (1.33 [1.20-1.48]). Obtaining less than 6 hours of sleep each night (compared to 7 hours) may increase type 2 diabetes risk by approximately 30%.The Sax Institute; Cancer Council New South Wales; the National Heart Foundation of Australia (New South Wales Division); The New South Wales Ministry of Health; Beyondblue: the National Depression Initiative; Ageing, Disability and Home Care, New South Wales Family and Community Services; the Australian Red Cross Blood Service; Uniting Care Ageing; the Australian National Health and Medical Research Council
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