273 research outputs found

    Statistical estimation of crosstalk for cable bundles

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    Predicting electromagnetic interference problems for cable bundles early in the design stage is of significant value for both automotive and other industries. Effective methods are needed for predicting interference when little design information is known. The random variation in parameters like wire position in the bundle require that statistical variations be taken into account. In the first part of this thesis, a method to analytically predict the reasonable worst-case crosstalk within a cable bundle is proposed. The method uses the per-unit-length LC matrices associated with the cross-sectional geometry of the bundle to generate probability a distribution function for mutual inductance and capacitance between wires within the bundle...In the second part of this thesis, a fast simulation method to estimate the crosstalk in cable bundles is proposed. The method makes use of the T-parameter (Transfer parameter) matrix and can be implemented with a simple MATLAB script --Abstract, page iv

    Structural Analysis and Deletion Mutagenesis Define Regions of QUIVER/SLEEPLESS that Are Responsible for Interactions with Shaker-Type Potassium Channels and Nicotinic Acetylcholine Receptors.

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    Ly6 proteins are endogenous prototoxins found in most animals. They show striking structural and functional parallels to snake α-neurotoxins, including regulation of ion channels and cholinergic signaling. However, the structural contributions of Ly6 proteins to regulation of effector molecules is poorly understood. This question is particularly relevant to the Ly6 protein QUIVER/SLEEPLESS (QVR/SSS), which has previously been shown to suppress excitability and synaptic transmission by upregulating potassium (K) channels and downregulating nicotinic acetylcholine receptors (nAChRs) in wake-promoting neurons to facilitate sleep in Drosophila. Using deletion mutagenesis, co-immunoprecipitations, ion flux assays, surface labeling and confocal microscopy, we demonstrate that only loop 2 is required for many of the previously described properties of SSS in transfected cells, including interactions with K channels and nAChRs. Collectively our data suggest that QVR/SSS, and by extension perhaps other Ly6 proteins, target effector molecules using limited protein motifs. Mapping these motifs may be useful in rational design of drugs that mimic or suppress Ly6-effector interactions to modulate nervous system function

    Validation of Worst-Case and Statistical Models for an Automotive EMC Expert System

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    Previous papers have presented algorithms for an EMC expert system used to predict potential electromagnetic compatibility problems in a vehicle early in the design process. Here, the accuracy of inductive and capacitive coupling algorithms are verified through representative measurements of crosstalk within an automobile. Worst-case estimates used by the algorithms are compared to measured values and are compared to values estimated using statistical methods. The worst-case algorithms performed well up to 10-20 MHz, but overestimated measured results by several dB in some cases and up to 10-15 dB in others. An approximate statistical variation of the current expert system algorithms also worked well and can help avoid overestimation of problems; however, worst-case estimates better ensure that problems will not be missed, especially in the absence of complete system information

    Estimation of the Statistical Variation of Crosstalk in Wiring Harnesses

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    Analyzing interference problems in vehicle wiring harnesses requires fast and accurate methods of approximating crosstalk. Worst-case approximations using lumped element models are fast and easy to use, but run the risk of overestimating problems. Statistical methods that account for the random variation of wire position help prevent overdesign, but are often difficult and time-consuming to apply and lack a clear link between problems and their cause. Here we investigate the use of simple lumped-element models to predict the statistical variation of crosstalk in wire harness bundles. Models are based on lumped-element approximations, where inductance and capacitance values are calculated for a single bundle crosssection, and only the circuit position is varied. Accuracy was evaluated by comparing results to numerical simulations. The method does a good job of quickly predicting the reasonable worst-case values of crosstalk due to inductive or capacitive coupling

    Tissue distribution of emulsified γ-tocotrienol and its long-term biological effects after subcutaneous administration

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    BACKGROUND: γ-tocotrienol (GT3), an analogue of vitamin E, has gained increasing scientific interest recently as it provides significant health benefits. It has been shown that emulsified GT3, after subcutaneous administration, has long-term biological effects. However, whether the effects are due to the increase of GT3 level in the early phase following administration or the persistent functions after accumulation in tissues is unknown. This study was conducted to determine the levels of GT3 in different tissues by high performance liquid chromatography (HPLC) with a fluorescence detector after a single-dose of GT3 with polyethylene glycol (PEG-400) emulsion via subcutaneous injection. Previous studies have explored that GT3 has favorable effects on bone and can inhibit osteoclast formation. To confirm the persistent biological activity of accumulated GT3 in tissues, receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) gene expressions, which have an important role in regulating osteoclast formation, were also evaluated in bone tissue on day 1, 3, 7 and 14 after a signal subcutaneous injection of GT3. METHODS: C57BL/6 female mice were administrated GT3 (100 mg/kg body weight) with PEG-400 emulsion by subcutaneous injection. GT3 levels in different tissues were determined by HPLC with a fluorescence detector. Gene expressions were measured by real-time PCR. RESULTS: GT3 predominantly accumulated in adipose and heart tissue, and was maintained at a relatively stable level in bone tissues after a single-dose administration. Accumulated GT3 in bone tissues significantly inhibited the increase in RANKL expression and the decrease in OPG expression induced by db-cAMP. CONCLUSIONS: We investigated the tissue distribution of GT3 with PEG emulsion by subcutaneous administration, which has never been reported so far. Our results suggest that GT3 with PEG emulsion accumulated in tissues is able to carry out a long-term biological effect and has therapeutic value for treating and preventing osteoporosis

    Diagnostic models of the pre-test probability of stable coronary artery disease: A systematic review

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    A comprehensive search of PubMed and Embase was performed in January 2015 to examine the available literature on validated diagnostic models of the pre-test probability of stable coronary artery disease and to describe the characteristics of the models. Studies that were designed to develop and validate diagnostic models of pre-test probability for stable coronary artery disease were included. Data regarding baseline patient characteristics, procedural characteristics, modeling methods, metrics of model performance, risk of bias, and clinical usefulness were extracted. Ten studies involving the development of 12 models and two studies focusing on external validation were identified. Seven models were validated internally, and seven models were validated externally. Discrimination varied between studies that were validated internally (C statistic 0.66-0.81) and externally (0.49-0.87). Only one study presented reclassification indices. The majority of better performing models included sex, age, symptoms, diabetes, smoking, and hyperlipidemia as variables. Only two diagnostic models evaluated the effects on clinical decision making processes or patient outcomes. Most diagnostic models of the pre-test probability of stable coronary artery disease have had modest success, and very few present data regarding the effects of these models on clinical decision making processes or patient outcomes
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