1,255 research outputs found

    Design of a fuzzy PID controller for a MEMS tunable capacitor for noise reduction in a voltage reference source

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    This study presents a conventional Ziegler-Nichols (ZN) Proportional Integral Derivative (PID) controller, having reviewed the mathematical modeling of the Micro Electro Mechanical Systems (MEMS) Tunable Capacitors (TCs), and also proposes a fuzzy PID controller which demonstrates a better tracking performance in the presence of measurement noise, in comparison with conventional ZN-based PID controllers. Referring to importance and impact of this research, the proposed controller takes advantage of fuzzy control properties such as robustness against noise. TCs are responsible for regulating the reference voltage when integrated into Alternating Current (AC) Voltage Reference Sources (VRS). Capacitance regulation for tunable capacitors in VRS is carried out by modulating the distance of a movable plate. A successful modulation depends on maintaining the stability around the pull-in point. This distance regulation can be achieved by the proposed controller which guarantees the tracking performance of the movable plate in moving towards the pull-in point, and remaining in this critical position. The simulation results of the tracking performance and capacitance tuning are very promising, subjected to measurement noise. Article Highlights This article deals with MEMS tunable capacitor dynamics and modeling, considering measurement noise. It designs and applies fuzzy PID control system for regulating MEMS voltage reference output. This paper contributes to robustness increase in pull-in performance of the tunable capacitor

    Coronary artery dominance and the risk of adverse clinical events following percutaneous coronary intervention: insights from the prospective, randomised TWENTE trial

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    Aims: To investigate the prognostic value of coronary dominance for various adverse clinical events following the implantation of drug-eluting stents. Methods and results: We assessed two-year follow-up data of 1,387 patients from the randomised TWENTE trial. Based on the origin of the posterior descending coronary artery, coronary circulation was categorised into left and non-left dominance (i.e., right and balanced). Target vessel-related myocardial infarction (MI) was defined according to the updated Academic Research Consortium (ARC) definition (2x upper reference limit of creatine kinase [CK], confirmed by CK-MB elevation), and periprocedural MI (PMI) as MI ≤48 hours following PCI. One hundred and thirty-six patients (9.8%) had left and 1,251 (90.2%) non-left dominance. Target lesions were more frequently located in dominant arteries (p<0.005). Left dominance was associated with more severe calcifications (p=0.006) and more bifurcation lesions (p=0.031). Non-left dominance tended to be less frequent in men (p=0.09). Left coronary dominance was associated with more target vessel-related MI (14 [10.3%] vs. 62 [5.0%], p=0.009). Left dominance independently predicted PMI (adjusted HR 2.19, 95% CI: 1.15-4.15, p=0.017), while no difference in other clinical endpoints was observed between dominance groups. Conclusions: In the population of the TWENTE trial, we observed a higher incidence of periprocedural myocardial infarction in patients who had left coronary dominance. - See more at: http://www.pcronline.com/eurointervention/ahead_of_print/201402-11/#sthash.p3Zkzx7X.dp

    Occurrence of Lead and Other Toxic Metals Derived from Drinking-Water Systems in Three West African Countries

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    Background: Exposure to toxic metals (TMs) such as lead can cause lifelong neurodevelopmental impairment and other adverse outcomes. TMs enter drinking water from human activity, geogenic contamination, and corrosion of water system components. Several studies report TM contamination in piped systems and private wells in high-income countries (HICs). However, few robust studies report on TM contamination in low- and middle-income countries (LMICs). Objectives: We characterized the occurrence and investigated sources of TM contamination in 261 rural water systems in three West African LMICs to inform prevention and management. Methods: Water samples were collected from 261 community water systems (handpumps and public taps) across rural Ghana, Mali, and Niger. Scrapings were collected from accessible components of a subset of these systems using a drill with acid-washed diamond-tipped bits. Samples were analyzed by inductively coupled plasma (ICP) mass spectrometry or ICP optical emission spectroscopy. Results: Of the TMs studied, lead most frequently occurred at levels of concern in sampled water system components and water samples. Lead mass fractions exceeded International Plumbing Code (IPC) recommended limits (0.25% wt/wt) for components in 82% (107/130) of systems tested; brass components proved most problematic, with 72% (26/36) exceeding IPC limits. Presence of a brass component in a water system increased expected lead concentrations in drinking-water samples by 3.8 times. Overall, lead exceeded World Health Organization (WHO) guideline values in 9% (24/261) of drinking-water samples across countries; these results are broadly comparable to results observed in many HICs. Results did not vary significantly by geography or system type. Discussion: Ensuring use of lead-free (<0.25% ) components in new water systems and progressively remediating existing systems could reduce drinking-water lead exposures and improve health outcomes for millions. However, reflexive decommissioning of existing systems may deprive users of sufficient water for health or drive them to riskier sources. Because supply chains for many water system components are global, TM monitoring, prevention, and management may be warranted in other LMICs beyond the study area as well. https://doi.org/10.1289/EHP780

    Advanced optical imaging in living embryos

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    Developmental biology investigations have evolved from static studies of embryo anatomy and into dynamic studies of the genetic and cellular mechanisms responsible for shaping the embryo anatomy. With the advancement of fluorescent protein fusions, the ability to visualize and comprehend how thousands to millions of cells interact with one another to form tissues and organs in three dimensions (xyz) over time (t) is just beginning to be realized and exploited. In this review, we explore recent advances utilizing confocal and multi-photon time-lapse microscopy to capture gene expression, cell behavior, and embryo development. From choosing the appropriate fluorophore, to labeling strategy, to experimental set-up, and data pipeline handling, this review covers the various aspects related to acquiring and analyzing multi-dimensional data sets. These innovative techniques in multi-dimensional imaging and analysis can be applied across a number of fields in time and space including protein dynamics to cell biology to morphogenesis

    Genetic polymorphisms of angiotensin-2 type 1 receptor and angiotensinogen and risk of renal dysfunction and coronary heart disease in type 2 diabetes mellitus

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    <p>Abstract</p> <p>Background</p> <p>Increased activation of the renin-angiotensin system (RAS) may be important in promoting coronary heart disease (CHD) and renal dysfunction, but limited data are available on associations between angiotensin type 1 receptor (<it>AGT1R</it>) and angiotensinogen (<it>AGT</it>) genotypes in type 2 diabetes.</p> <p>Methods</p> <p>Study participants were diabetics from the Health Professionals Follow-Up Study (HPFS) and the Nurses' Health Study (NHS). We analyzed single nucleotide polymorphisms (SNPs) associated with cardiovascular pathophysiology (including <it>AGT1R </it>T573C, <it>AGT1R </it>A1166C, and <it>AGT </it>M235T) and presence of renal dysfunction (eGFR<60 ml/min/1.73 m<sup>2</sup>) or history of CHD.</p> <p>Results</p> <p>The <it>AGT1R </it>1166 C-allele was associated with eGFR<60 ml/min/1.73 m<sup>2 </sup>(multivariable OR 1.63 [1.01, 2.65]) in the HPFS men (n = 733) and in the combined dataset (n = 1566) (OR 1.42 [1.02, 1.98]). The <it>AGT1R </it>1166 C-allele was also associated with CHD in men (OR 1.57 [1.10, 2.24]). In NHS women (n = 833), <it>AGT </it>235T-allele was associated with CHD (OR 1.72 [1.20, 2.47]). Removal of hypertension from the fully adjusted models did not influence results, suggesting that the associations may not be mediated by hypertension. There were significant interactions between sex and <it>AGT1R </it>1166 C-allele (p = 0.008) and <it>AGT </it>M235T (p = 0.03) in models for CHD. No significant associations were seen between <it>AGT1R </it>T573 C-allele and renal dysfunction or CHD.</p> <p>Conclusion</p> <p>Polymorphisms in <it>AGT1R </it>and <it>AGT </it>genes are associated with renal dysfunction and CHD in type 2 diabetes and further support the important role of the RAS in these complications. Sex may modify associations between <it>AGT1R </it>1166 C-allele and <it>AGT </it>235T and CHD in type 2 diabetes.</p

    Quantification of SLIT-ROBO transcripts in hepatocellular carcinoma reveals two groups of genes with coordinate expression

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    <p>Abstract</p> <p>Background</p> <p>SLIT-ROBO families of proteins mediate axon pathfinding and their expression is not solely confined to nervous system. Aberrant expression of <it>SLIT-ROBO </it>genes was repeatedly shown in a wide variety of cancers, yet data about their collective behavior in hepatocellular carcinoma (HCC) is missing. Hence, we quantified <it>SLIT-ROBO </it>transcripts in HCC cell lines, and in normal and tumor tissues from liver.</p> <p>Methods</p> <p>Expression of <it>SLIT-ROBO </it>family members was quantified by real-time qRT-PCR in 14 HCC cell lines, 8 normal and 35 tumor tissues from the liver. ANOVA and Pearson's correlation analyses were performed in R environment, and different clinicopathological subgroups were pairwise compared in Minitab. Gene expression matrices of cell lines and tissues were analyzed by Mantel's association test.</p> <p>Results</p> <p>Genewise hierarchical clustering revealed two subgroups with coordinate expression pattern in both the HCC cell lines and tissues: <it>ROBO1</it>, <it>ROBO2</it>, <it>SLIT1 </it>in one cluster, and <it>ROBO4</it>, <it>SLIT2</it>, <it>SLIT3 </it>in the other, respectively. Moreover, <it>SLIT-ROBO </it>expression predicted <it>AFP</it>-dependent subgrouping of HCC cell lines, but not that of liver tissues. <it>ROBO1 </it>and <it>ROBO2 </it>were significantly up-regulated, whereas <it>SLIT3 </it>was significantly down-regulated in cell lines with high-<it>AFP </it>background. When compared to normal liver tissue, <it>ROBO1 </it>was found to be significantly overexpressed, while <it>ROBO4 </it>was down-regulated in HCC. We also observed that <it>ROBO1 </it>and <it>SLIT2 </it>differentiated histopathological subgroups of liver tissues depending on both tumor staging and differentiation status. However, <it>ROBO4 </it>could discriminate poorly differentiated HCC from other subgroups.</p> <p>Conclusion</p> <p>The present study is the first in comprehensive and quantitative evaluation of <it>SLIT-ROBO </it>family gene expression in HCC, and suggests that the expression of <it>SLIT-ROBO </it>genes is regulated in hepatocarcinogenesis. Our results implicate that <it>SLIT-ROBO </it>transcription profile is bi-modular in nature, and that each module shows intrinsic variability. We also provide quantitative evidence for potential use of <it>ROBO1</it>, <it>ROBO4 </it>and <it>SLIT2 </it>for prediction of tumor stage and differentiation status.</p
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