41 research outputs found

    Thermo-Chromic Response of Polymer Stabilized Cholesteric Liquid Crystal for Thermal Imaging

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    Cholesteric liquid crystal (Ch-LC) exhibits many remarkable optical properties due to formation of a macroscopic helical structure. A low amount of monomer (5wt.%) is dispersed into cholesteric liquid crystal and get polymerized under UV radiations to form polymer stabilized cholesteric texture (PSCT). The thermo-chromic response made this device suitable for the developing applications in thermal imaging. Temperature based measurements of PSCT exploits the key property of some polymer stabilized cholesteric liquid crystals (PSCLC) to reflect definite colors at specific temperatures. The selective color of PSCT texture shifts with raise in temperature from 30oC to 85oC, which can be utilized in thermal imaging applications

    Experimental and neural network approach to effective electrical conductivity of carbon nanotubes dispersed chiral nematic liquid crystals

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    Single walled carbon nanotubes (SWCNT’s) doped cholesteric liquid crystal composite has been prepared and characterized for their electrical responses. Also theoretically, an artificial neural network (ANN) approach has been trained for predicting the effective electrical conductivity of these composites. The ANN models are based on a feedforward backpropagation (FFBP) network with such training functions as the adaptive learning rate (GDX), gradient descent with adaptive learning rate (GDA), gradient descent (GD), conjugates gradient with Powell-Beale restarts (CGB), one-step secant (OSS), and Levenberg–Marquardt (LM), and training algorithms run at the uniform threshold transfer functions-Tangent sigmoid (TANSIG) and pure linear (PURELIN) for 1000 epochs. Our modeling confirms that the expected effective electrical conductivity by different training functions of ANN is in higher agreement with the experimental results of SWCNT doped CLC composites

    Regulation of Neuronal Cell Death by c-Abl-Hippo/MST2 Signaling Pathway

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    BACKGROUND: Mammalian Ste20-like kinases (MSTs) are the mammalian homologue of Drosophila hippo and play critical roles in regulation of cell death, organ size control, proliferation and tumorigenesis. MSTs exert pro-apoptotic function through cleavage, autophosphorylation and in turn phosphorylation of downstream targets, such as Histone H2B and FOXO (Forkhead box O). Previously we reported that protein kinase c-Abl mediates oxidative stress-induced neuronal cell death through phosphorylating MST1 at Y433, which is not conserved among mammalian MST2, Drosophila Hippo and C.elegans cst-1/2. METHODOLOGY/PRINCIPAL FINDINGS: Using immunoblotting, in vitro kinase and cell death assay, we demonstrate that c-Abl kinase phosphorylates MST2 at an evolutionarily conserved site, Y81, within the kinase domain. We further show that the phosphorylation of MST2 by c-Abl leads to the disruption of the interaction with Raf-1 proteins and the enhancement of homodimerization of MST2 proteins. It thereby enhances the MST2 activation and induces neuronal cell death. CONCLUSIONS/SIGNIFICANCE: The identification of the c-Abl tyrosine kinase as a novel upstream activator of MST2 suggests that the conserved c-Abl-MST signaling cascade plays an important role in oxidative stress-induced neuronal cell death

    Cytogenetical studies in five Atlantic Anguilliformes fishes

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    The order Anguilliformes comprises 15 families, 141 genera and 791 fish species. Eight families had at least one karyotyped species, with a prevalence of 2n = 38 chromosomes and high fundamental numbers (FN). The only exception to this pattern is the family Muraenidae, in which the eight species analyzed presented 2n = 42 chromosomes. Despite of the large number of Anguilliformes species, karyotypic reports are available for only a few representatives. In the present work, a species of Ophichthidae, Myrichthys ocellatus (2n = 38; 8m+14sm+10st+6a; FN = 70) and four species of Muraenidae, Enchelycore nigricans (2n = 42; 6m+8sm+12st+16a; FN = 68), Gymnothorax miliaris (2n = 42; 14m+18sm+10st; FN = 84), G. vicinus (2n = 42; 8m+6sm+28a; FN = 56) and Muraena pavonina (2n = 42; 6m+4sm+32a; FN = 52), collected along the Northeastern coast of Brazil and around the St Peter and St Paul Archipelago were analyzed. Typical large metacentric chromosomes were observed in all species. Conspicuous polymorphic heterochromatic regions were observed at the centromeres of most chromosomes and at single ribosomal sites. The data obtained for Ophichthidae corroborate the hypothesis of a karyotypic diversification mainly due to pericentric inversions and Robertsonian rearrangements, while the identification of constant chromosome numbers in Muraenidae (2n = 42) suggests a karyotype diversification through pericentric inversions and heterochromatin processes

    Karyotype differentiation in 19 species of river loach fishes (Nemacheilidae, Teleostei): extensive variability associated with rDNA and heterochromatin distribution and its phylogenetic and ecological interpretation

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    Understanding Objections to One Anastomosis (Mini) Gastric Bypass: A Survey of 417 Surgeons Not Performing this Procedure.

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    BACKGROUND Despite published experience with thousands of patients, the uptake of One Anastomosis/Mini Gastric Bypass (OAGB/MGB) has been less than enthusiastic and many surgeons still harbour objections to this procedure. The purpose of this study was to understand these objections scientifically. METHODS Bariatric surgeons from around the world were invited to participate in a questionnaire-based survey on SurveyMonkeyŸ. Surgeons already performing this procedure were excluded. RESULTS Four hundred seventeen bariatric surgeons (from 42 countries) not currently performing OAGB/MGB took the survey. There were 211/414 (50.97%) and 188/414 (45.41%) respondents who expressed concerns that it will lead to an increased risk of gastric and oesophageal cancers respectively. A total of 62/416 (14.9%) and 201/413 (n = 48.6%) surgeons respectively felt that OAGB/MGB was associated with a higher early (30-day) and late complication rate compared to the RYGB. Moreover, 7.8% (n = 32/411) and 16.26% (n = 67/412) of the respondents were concerned that OAGB/MGB carried a higher early (30-day) and late mortality, respectively, in comparison with the RYGB. There were 79/410 (19.27%) and 88/413 (21.3%) respondents who were concerned that OAGB/MGB was not an effective procedure for weight loss and co-morbidity resolution, respectively. A total of 258/411 (62.77%) respondents reported that OAGB/MGB was not approved by their national society as a mainstream bariatric procedure; 51.0% of these surgeons would start performing this procedure if it was. CONCLUSIONS Surgeons not performing OAGB/MGB cite a number of concerns for not performing this operation. This survey is the first scientific attempt to understand these objections scientifically
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