250 research outputs found
Ionic liquid incorporated PVC based polymer electrolytes: electrical and dielectric properties
This paper is focussed on conductivity and dielectric properties of Poly (vinyl) chloride (PVC)- ammonium triflate (NH4CF3SO3) - butyltrimethyl ammonium bis (trifluoromethyl sulfonyl) imide (Bu3MeNTf2N) ionic liquid, electrolyte system. The electrolyte is prepared by solution cast technique. In this work, the sample containing 30 wt. % NH4CF3SO3 exhibits the highest room temperature conductivity of 2.50 × 10-7 S cm-1. Ionic liquid is added in various quantities to the 70 wt. % PVC-30 wt. % NH4CF3SO3 composition in order to enhance the conductivity of the sample. The highest conductivity at room temperature is obtained for the sample containing 15 wt. % Bu3MeNTf2N with a value of 1.56 × 10 -4 S cm-1. The effects of ionic liquid addition on the frequency dependent dielectric properties of PVC based electrolytes is investigated by electrochemical impedance spectroscopy (EIS) at room temperature. The values of dielectric constant were found to increase with increasing conductivity of the samples. Analysis of the ac conductivity data showed the electrolytes to be of the non-Debye type
Joint Optical Flow and Temporally Consistent Semantic Segmentation
The importance and demands of visual scene understanding have been steadily
increasing along with the active development of autonomous systems.
Consequently, there has been a large amount of research dedicated to semantic
segmentation and dense motion estimation. In this paper, we propose a method
for jointly estimating optical flow and temporally consistent semantic
segmentation, which closely connects these two problem domains and leverages
each other. Semantic segmentation provides information on plausible physical
motion to its associated pixels, and accurate pixel-level temporal
correspondences enhance the accuracy of semantic segmentation in the temporal
domain. We demonstrate the benefits of our approach on the KITTI benchmark,
where we observe performance gains for flow and segmentation. We achieve
state-of-the-art optical flow results, and outperform all published algorithms
by a large margin on challenging, but crucial dynamic objects.Comment: 14 pages, Accepted for CVRSUAD workshop at ECCV 201
Anomalous dielectric constant and AC conductivity in mixed transition-metal-ion xFe2O3-(20 - x)MnO2-80TeO2 glass system
Glasses with xFe2O3–(20−x)MnO2–80TeO2 (x=2, 5, 10, 15, and 20 mol%) composition were prepared by meltquenching technique to investigate the effects of mixed-transition metal ion Fe2 +/3 +//Mn3 +/4 + on AC conductivity and dielectric properties using impedance spectroscopy. Dielectric constant showed strong variation with Fe2O3 at a frequency ≥10 kHz, where έ decreased to a minimum value at x =10 mol% before increasing for x> 10%. The decrease in έ may be attributed to some form of hindrance effect on heavy dipoles caused by the mixed transition-ion effect (MTE). Meanwhile, variation of AC conductivity with Fe2O3 showed non-linear increase for x ≤ 10 mol% before dropping to a minimum at 15 mol% Fe2O3. This result was attributed to Anderson localization because of the disorder in the glass system. Conductivity analysis showed that the conduction mechanism at the dispersion region for x = 2 mol% followed the correlated barrier hopping (CBH) model, while the mechanism transformed to the overlapping large polaron tunnelling (OLPT) model at higher Fe2O3, content (x > 2 mol%). The electric modulus of the investigated samples showed asymmetric peak of the imaginary part of electric modulus (M¢¢), which reflected a non-Debye type relaxation
Hybrid carboxymethyl kappa-carrageenan/carboxymethyl cellulose- based biopolymer electrolytes for dye-sensitized solar cell application
Natural biopolymers have recently attracted a lot of attention for the development of new polymer electrolytes due to their environmental friendliness, nontoxicity, and abundance in nature. Biopolymer electrolytes based on carboxymethyl kappa carrageenan/carboxymethyl cellulose incorporated with sodium iodide were prepared and their structural and electrochemical stability were investigated using electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, transference number measurement, and linear sweep voltammetry. The film containing 30 wt% sodium iodide had the highest ionic conductivity and the highest relative number of charge carriers at room temperature. The relative number of charge carriers for each prepared electrolyte film in this study increased with salt concentration, according to Barker's electrolyte dissociation theory. The highest conducting electrolyte and the lowest salt concentration electrolyte films were used to fabricate and characterise dye-sensitized solar cell (DSSC). These DSSCs responded well to a light intensity of 100 mW cm-2
H-reflex amplitude asymmetry is an earlier sign of nerve root involvement than latency in patients with S1 radiculopathy
Abstract Background Based on our clinical experience, the H-reflex amplitude asymmetry might be an earlier sign of nerve root involvement than latency in patients with S1 radiculopathy. However, no data to support this assumption are available. The purpose of this study was to review and report the electrophysiological changes in H-reflex amplitude and latency in patients with radiculopathy in order to determine if there is any evidence to support the assumption that H-reflex amplitude is an earlier sign of nerve root involvement than latency. Results Patients with radiculopathy showed significant amplitude asymmetry when compared with healthy controls. However, latency was not always significantly different between patients and healthy controls. These findings suggest nerve root axonal compromise that reduced reflex amplitude earlier than the latency parameter (demyelination) during the pathologic processes. Conclusion Contrary to current clinical thought, H-reflex amplitude asymmetry is an earlier sign/parameter of nerve root involvement in patients with radiculopathy compared with latency.</p
Testing and Validation of High Density Resequencing Microarray for Broad Range Biothreat Agents Detection
Rapid and effective detection and identification of emerging microbiological threats and potential biowarfare agents is very challenging when using traditional culture-based methods. Contemporary molecular techniques, relying upon reverse transcription and/or polymerase chain reaction (RT-PCR/PCR) provide a rapid and effective alternative, however, such assays are generally designed and optimized to detect only a limited number of targets, and seldom are capable of differentiation among variants of detected targets. To meet these challenges, we have designed a broad-range resequencing pathogen microarray (RPM) for detection of tropical and emerging infectious agents (TEI) including biothreat agents: RPM-TEI v 1.0 (RPM-TEI). The scope of the RPM-TEI assay enables detection and differential identification of 84 types of pathogens and 13 toxin genes, including most of the class A, B and C select agents as defined by the Centers for Disease Control and Prevention (CDC, Atlanta, GA). Due to the high risks associated with handling these particular target pathogens, the sensitivity validation of the RPM-TEI has been performed using an innovative approach, in which synthetic DNA fragments are used as templates for testing the assay's limit of detection (LOD). Assay specificity and sensitivity was subsequently confirmed by testing with full-length genomic nucleic acids of selected agents. The LOD for a majority of the agents detected by RPM-TEI was determined to be at least 104 copies per test. Our results also show that the RPM-TEI assay not only detects and identifies agents, but is also able to differentiate near neighbors of the same agent types, such as closely related strains of filoviruses of the Ebola Zaire group, or the Machupo and Lassa arenaviruses. Furthermore, each RPM-TEI assay results in specimen-specific agent gene sequence information that can be used to assess pathogenicity, mutations, and virulence markers, results that are not generally available from multiplexed RT-PCR/PCR-based detection assays
Diabetes in pregnancy among indigenous women in Australia, Canada, New Zealand, and the United States: a method for systematic review of studies with different designs
<p>Abstract</p> <p>Background</p> <p>Diabetes in pregnancy, which includes gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM), is associated with poor outcomes for both mother and infant during pregnancy, at birth and in the longer term. Recent international guidelines recommend changes to the current GDM screening criteria. While some controversy remains, there appears to be consensus that women at high risk of T2DM, including indigenous women, should be offered screening for GDM early in pregnancy, rather than waiting until 24-28 weeks as is current practice. A range of criteria should be considered before changing screening practice in a population sub-group, including: prevalence, current practice, acceptability and whether adequate treatment pathways and follow-up systems are available. There are also specific issues related to screening in pregnancy and indigenous populations. The evidence that these criteria are met for indigenous populations is yet to be reported. A range of study designs can be considered to generate relevant evidence for these issues, including epidemiological, observational, qualitative, and intervention studies, which are not usually included within a single systematic review. The aim of this paper is to describe the methods we used to systematically review studies of different designs and present the evidence in a pragmatic format for policy discussion.</p> <p>Methods/Design</p> <p>The inclusion criteria will be broad to ensure inclusion of the critical perspectives of indigenous women. Abstracts of the search results will be reviewed by two persons; the full texts of all potentially eligible papers will be reviewed by one person, and 10% will be checked by a second person for validation. Data extraction will be standardised, using existing tools to identify risks for bias in intervention, measurement, qualitative studies and reviews; and adapting criteria for appraising risk for bias in descriptive studies. External validity (generalisability) will also be appraised. The main findings will be synthesised according to the criteria for population-based screening and summarised in an adapted "GRADE" tool.</p> <p>Discussion</p> <p>This will be the first systematic review of all the published literature on diabetes in pregnancy among indigenous women. The method provides a pragmatic approach for synthesizing relevant evidence from a range of study designs to inform the current policy discussion.</p
An Image-Based High-Content Screening Assay for Compounds Targeting Intracellular Leishmania donovani Amastigotes in Human Macrophages
Leishmaniasis is a tropical disease threatening 350 million people from endemic regions. The available drugs for treatment are inadequate, with limitations such as serious side effects, parasite resistance or high cost. Driven by this need for new drugs, we developed a high-content, high-throughput image-based screening assay targeting the intracellular amastigote stage of different species of Leishmania in infected human macrophages. The in vitro infection protocol was adapted to a 384-well-plate format, enabling acquisition of a large amount of readouts by automated confocal microscopy. The reading method was based on DNA staining and required the development of a customized algorithm to analyze the images, which enabled the use of non-modified parasites. The automated analysis generated parameters used to quantify compound activity, including infection ratio as well as the number of intracellular amastigote parasites and yielded cytotoxicity information based on the number of host cells. Comparison of this assay with one that used the promastigote form to screen 26,500 compounds showed that 50% of the hits selected against the intracellular amastigote were not selected in the promastigote screening. These data corroborate the idea that the intracellular amastigote form of the parasite is the most appropriate to be used in primary screening assay for Leishmania
Perturbation of adhesion molecule-mediated chondrocyte-matrix interactions by 4-hydroxynonenal binding: implication in osteoarthritis pathogenesis
ABSTRACT: INTRODUCTION: Objectives were to investigate whether interactions between human osteoarthritic chondrocytes and 4-hydroxynonenal (HNE)-modified type II collagen (Col II) affect cell phenotype and functions and to determine the protective role of carnosine (CAR) treatment in preventing these effects. METHODS: Human Col II was treated with HNE at different molar ratios (MR) (1:20 to 1:200; Col II:HNE). Articular chondrocytes were seeded in HNE/Col II adduct-coated plates and incubated for 48 hours. Cell morphology was studied by phase-contrast and confocal microscopy. Adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and alpha1beta1 integrin at protein and mRNA levels were quantified by Western blotting, flow cytometry and real-time reverse transcription-polymerase chain reaction. Cell death, caspases activity, prostaglandin E2 (PGE2), metalloproteinase-13 (MMP-13), mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-kappaB) were assessed by commercial kits. Col II, cyclooxygenase-2 (COX-2), MAPK, NF-kappaB-p65 levels were analyzed by Western blotting. The formation of alpha1beta1 integrin-focal adhesion kinase (FAK) complex was revealed by immunoprecipitation. RESULTS: Col II modification by HNE at MR approximately 1:20, strongly induced ICAM-1, alpha1beta1 integrin and MMP-13 expression as well as extracellular signal-regulated kinases 1 and 2 (ERK1/2) and NF-kappaB-p65 phosphorylation without impacting cell adhesion and viability or Col II expression. However, Col II modification with HNE at MR approximately 1:200, altered chondrocyte adhesion by evoking cell death and caspase-3 activity. It inhibited alpha1beta1 integrin and Col II expression as well as ERK1/2 and NF-kappaB-p65 phosphorylation, but, in contrast, markedly elicited PGE2 release, COX-2 expression and p38 MAPK phosphorylation. Immunoprecipitation assay revealed the involvement of FAK in cell-matrix interactions through the formation of alpha1beta1 integrin-FAK complex. Moreover, the modification of Col II by HNE at a 1:20 or approximately 1:200 MR affects parameters of the cell shape. All these effects were prevented by CAR, an HNE-trapping drug. CONCLUSIONS: Our novel findings indicate that HNE-binding to Col II results in multiple abnormalities of chondrocyte phenotype and function, suggesting its contribution in osteoarthritis development. CAR was shown to be an efficient HNE-snaring agent capable of counteracting these outcomes
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