328 research outputs found

    SPARCS: Stream-processing architecture applied in real-time cyber-physical security

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    In this paper, we showcase a complete, end-To-end, fault tolerant, bandwidth and latency optimized architecture for real time utilization of data from multiple sources that allows the collection, transport, storage, processing, and display of both raw data and analytics. This architecture can be applied for a wide variety of applications ranging from automation/control to monitoring and security. We propose a practical, hierarchical design that allows easy addition and reconfiguration of software and hardware components, while utilizing local processing of data at sensor or field site ('fog computing') level to reduce latency and upstream bandwidth requirements. The system supports multiple fail-safe mechanisms to guarantee the delivery of sensor data. We describe the application of this architecture to cyber-physical security (CPS) by supporting security monitoring of an electric distribution grid, through the collection and analysis of distribution-grid level phasor measurement unit (PMU) data, as well as Supervisory Control And Data Acquisition (SCADA) communication in the control area network

    Identification of 5-Hydroxy-6-indolyl-O-sulfate in Urine of Patients with Malignant MelanomaIdentification of 5-Hydroxy-6-indolyl-O-sulfate in Urine of Patients with Malignant Melanoma

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    It has previously been shown that enzymatically hydrolyzed urine of patients with malignant melanoma contains 5,6-dihydroxyindole (5,6DHI). In this study we describe the elucidation of the entire structure of urinary 5,6DHI-conjugate. Differential hydrolysis of melanotic urine revealed that, in contrast to β-glucuronidase, sulfatase can liberate 5,6DHI from its conjugated form. 5,6DHI-sulfate was synthesized by reacting 5,6DHI with sulfur trioxide trimethylamine complex. Thin-layer chromatography (TLC) documented its close similarity to the Thormählen-positive compound usually entitled “C.” Gas chromatographic-mass spectrometric (GC-MS) analysis of methylated and subsequently hydrolyzed synthetic 5,6DHI-sulfate showed that the synthetic product consisted of a mixture of 5-hydroxy-6- indolyl-O-sulfate and 6-hydroxy-5-indolyl-O-sulfate (with a certain amount of 5,6DHI-disulfate). 5,6DHI-sulfate was purified with use of DEAE-cellulose column chromatography from melanotic urine. Methylation of this conjugate with deuterated dimethylsulfate and subsequent GC-MS analysis of the hydrolyzed product provided evidence that 5,6DHI from melanotic urine was almost exclusively sulfated in position 6. It was concluded (1) that 5,6DHI is excreted as a 6-O-sulfate, and (2) that this compound is consistent with Thormählen-positive compound “C.

    In vivo – in vitro toxicogenomic comparison of TCDD-elicited gene expression in Hepa1c1c7 mouse hepatoma cells and C57BL/6 hepatic tissue

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    BACKGROUND: In vitro systems have inherent limitations in their ability to model whole organism gene responses, which must be identified and appropriately considered when developing predictive biomarkers of in vivo toxicity. Systematic comparison of in vitro and in vivo temporal gene expression profiles were conducted to assess the ability of Hepa1c1c7 mouse hepatoma cells to model hepatic responses in C57BL/6 mice following treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). RESULTS: Gene expression analysis and functional gene annotation indicate that Hepa1c1c7 cells appropriately modeled the induction of xenobiotic metabolism genes in vivo. However, responses associated with cell cycle progression and proliferation were unique to Hepa1c1c7 cells, consistent with the cell cycle arrest effects of TCDD on rapidly dividing cells. In contrast, lipid metabolism and immune responses, representative of whole organism effects in vivo, were not replicated in Hepa1c1c7 cells. CONCLUSION: These results identified inherent differences in TCDD-mediated gene expression responses between these models and highlighted the limitations of in vitro systems in modeling whole organism responses, and additionally identified potential predictive biomarkers of toxicity

    Protocols for the assurance of microarray data quality and process control

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    Microarrays represent a powerful technology that provides the ability to simultaneously measure the expression of thousands of genes. However, it is a multi-step process with numerous potential sources of variation that can compromise data analysis and interpretation if left uncontrolled, necessitating the development of quality control protocols to ensure assay consistency and high-quality data. In response to emerging standards, such as the minimum information about a microarray experiment standard, tools are required to ascertain the quality and reproducibility of results within and across studies. To this end, an intralaboratory quality control protocol for two color, spotted microarrays was developed using cDNA microarrays from in vivo and in vitro dose-response and time-course studies. The protocol combines: (i) diagnostic plots monitoring the degree of feature saturation, global feature and background intensities, and feature misalignments with (ii) plots monitoring the intensity distributions within arrays with (iii) a support vector machine (SVM) model. The protocol is applicable to any laboratory with sufficient datasets to establish historical high- and low-quality data

    Release characteristics of selected carbon nanotube polymer composites

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    Multi-walled carbon nanotubes (MWCNTs) are commonly used in polymer formulations to improve strength, conductivity, and other attributes. A developing concern is the potential for carbon nanotube polymer nanocomposites to release nanoparticles into the environment as the polymer matrix degrades or is mechanically stressed. Here, we review characteristics related to release potential of five sets of polymer systems: epoxy, polyamide, polyurethane, polyethylene, and polycarbonate. Our review includes consideration of general characteristics and use of the polymer (as related to potential MWCNT release) and its MWCNT composites; general potential for nanomaterial release (particularly MWCNTs) due to degradation and mechanical stresses during use; and potential effects of stabilizers and plasticizers on polymer degradation. We examine UV degradation, temperature extremes, acid-base catalysis, and stresses such as sanding. Based on a high-level summary of the characteristics considered, the potential for release of MWCNT with typical, intended consumer use is expected to be low. © 2013 Elsevier Ltd. All rights reserved

    Cross-species gene expression analysis of species specific differences in the preclinical assessment of pharmaceutical compounds

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    Animals are frequently used as model systems for determination of safety and efficacy in pharmaceutical research and development. However, significant quantitative and qualitative differences exist between humans and the animal models used in research. This is as a result of genetic variation between human and the laboratory animal. Therefore the development of a system that would allow the assessment of all molecular differences between species after drug exposure would have a significant impact on drug evaluation for toxicity and efficacy. Here we describe a cross-species microarray methodology that identifies and selects orthologous probes after cross-species sequence comparison to develop an orthologous cross-species gene expression analysis tool. The assumptions made by the use of this orthologous gene expression strategy for cross-species extrapolation is that; conserved changes in gene expression equate to conserved pharmacodynamic endpoints. This assumption is supported by the fact that evolution and selection have maintained the structure and function of many biochemical pathways over time, resulting in the conservation of many important processes. We demonstrate this cross-species methodology by investigating species specific differences of the peroxisome proliferatoractivator receptor (PPAR) a response in rat and human

    Approaches and considerations for the assessment of immunotoxicity for environmental chemicals: A workshop summary

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    AbstractAs experience is gained with toxicology testing and as new assays and technologies are developed, it is critical for stakeholders to discuss opportunities to advance our overall testing strategies. To facilitate these discussions, a workshop on practices for assessing immunotoxicity for environmental chemicals was held with the goal of sharing perspectives on immunotoxicity testing strategies and experiences, developmental immunotoxicity (DIT), and integrated and alternative approaches to immunotoxicity testing. Experiences across the chemical and pharmaceutical industries suggested that standard toxicity studies, combined with triggered-based testing approaches, represent an effective and efficient approach to evaluate immunotoxic potential. Additionally, discussions on study design, critical windows, and new guideline approaches and experiences identified important factors to consider before initiating DIT evaluations including assay choice and timing and the impact of existing adult data. Participants agreed that integrating endpoints into standard repeat-dose studies should be considered for fulfilling any immunotoxicity testing requirements, while also maximizing information and reducing animal use. Participants also acknowledged that in vitro evaluation of immunosuppression is complex and may require the use of multiple assays that are still being developed. These workshop discussions should contribute to developing an effective but more resource and animal efficient approach for evaluating chemical immunotoxicity

    Colesevelam enhances the beneficial effects of brown fat activation on hyperlipidemia and atherosclerosis development

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    Aims Brown fat activation accelerates the uptake of cholesterol-enriched remnants by the liver and thereby lowers plasma cholesterol, consequently protecting against atherosclerosis development. Hepatic cholesterol is then converted into bile acids (BAs) that are secreted into the intestine and largely maintained within the enterohepatic circulation. We now aimed to evaluate the effects of prolonged brown fat activation combined with inhibition of intestinal BA reabsorption on plasma cholesterol metabolism and atherosclerosis development and results APOE∗3-Leiden.CETP mice with humanized lipoprotein metabolism were treated for 9 weeks with the selective b3-adrenergic receptor (AR) agonist CL316,243 to substantially activate brown fat. Prolonged b3-AR agonism reduced faecal BA excretion (-31%), while markedly increasing plasma levels of total BAs (258%), cholic acid-derived BAs (295%), and chenodeoxycholic acid-derived BAs (217%), and decreasing the expression of hepatic genes involved in BA production. In subsequent experiments, mice were additionally treated with the BA sequestrant Colesevelam to inhibit BA reabsorption. Concomitant intestinal BA sequestration increased faecal BA excretion, normalized plasma BA levels, and reduced hepatic cholesterol. Moreover, concomitant BA sequestration further reduced plasma total cholesterol (-49%) and non-high-density lipoprotein cholesterol (-56%), tended to further attenuate atherosclerotic lesion area (-54%). Concomitant BA sequestration further increased the proportion of lesion-free valves (34%) and decreased the relative macrophage area within the lesion (-26%), thereby further increasing the plaque stability index (44%). Conclusion BA sequestration prevents the marked accumulation of plasma BAs as induced by prolonged brown fat activation, thereby further improving cholesterol metabolism and reducing atherosclerosis development. These data suggest that combining brown fat activation with BA sequestration is a promising new therapeutic strategy to reduce hyperlipidaemia and cardiovascular diseases

    Novel role of a triglyceride-synthesizing enzyme:DGAT1 at the crossroad between triglyceride and cholesterol metabolism

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    AbstractAcyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) is a key enzyme in triacylglycerol (TG) biosynthesis. Here we show that genetic deficiency and pharmacological inhibition of DGAT1 in mice alters cholesterol metabolism. Cholesterol absorption, as assessed by acute cholesterol uptake, was significantly decreased in the small intestine and liver upon DGAT1 deficiency/inhibition. Ablation of DGAT1 in the intestine (I-DGAT1−/−) alone is sufficient to cause these effects. Consequences of I-DGAT1 deficiency phenocopy findings in whole-body DGAT1−/− and DGAT1 inhibitor-treated mice. We show that deficiency/inhibition of DGAT1 affects cholesterol metabolism via reduced chylomicron size and increased trans-intestinal cholesterol excretion. These effects are independent of cholesterol uptake at the apical surface of enterocytes but mediated through altered dietary fatty acid metabolism. Our findings provide insight into a novel role of DGAT1 and identify a pathway by which intestinal DGAT1 deficiency affects whole-body cholesterol homeostasis in mice. Targeting intestinal DGAT1 may represent a novel approach for treating hypercholesterolemia
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