76 research outputs found

    Cytotoxicity, antibacterial and physicochemical properties of a new epoxy resin-based endodontic sealer containing calcium hydroxide

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    This study evaluated the cytotoxicity, antibacterial and physicochemical properties of a new epoxy resin-based endodontic sealer containing calcium-hydroxide Sealer Plus. AH Plus was used as a reference for comparison. Cytotoxicity evaluation was performed according to ISO-10993-5 specifications using MTT assay to check the 3T3 cells viability at 1- to 4-week periods. Antibacterial activity was evaluated using a direct contact test against Enterococcus faecalis. Radiopacity, solubility and flow evaluations were performed according to ISO-6876/2012 specifications. Setting time was assessed following the ANSI/ADA-standard-n.57. The pH level was measured at 3,24,48,72, and 168 hours. Data were statistically analyzed using t-test. The signi?cance level adopted was P0.05). Direct contact results revealed that both freshly prepared sealers has antibacterial effects against Enterococcus faecalis. However, after 7 days both sealers had lost much of their antibacterial effects. Although AH Plus presented higher radiopacity and flow than Sealer Plus (P0.05). AH Plus showed a higher setting time when compared to Sealer Plus (P<0.05). AH Plus and Sealer Plus showed a neutral pH during all tested periods (P<0.05). It can be concluded that Sealer Plus showed suitable properties to be used as an endodontic sealer, comparable with those obtained by AH Plus

    Shear-Modulus Investigations of Monohydroxy Alcohols: Evidence for a Short-Chain-Polymer Rheological Response

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    In addition to the ubiquitous structural relaxation of viscous supercooled liquids, monohydroxy alcohols and several other hydrogen-bonded systems display a strong single-exponential electrical low-frequency absorption. So far, this so-called Debye process could be observed only using dielectric techniques. Exploiting a combination of broad-band and high-resolution rheology experiments for three isomeric octanols, unambiguous mechanical evidence for the Debye process is found. Its spectral signature is similar to the viscoelastic fingerprint of small-chain polymers, enabling us to estimate the effective molecular weight for the supramolecular structure formed by the studied monohydroxy alcohols. This finding opens the venue for the application of further non-dielectric techniques directed at unraveling the microscopic nature of the Debye process and for an understanding of this phenomenon in terms of polymer concepts.Comment: 12 pages, 4 figure

    Corresponding States of Structural Glass Formers

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    The variation with respect to temperature T of transport properties of 58 fragile structural glass forming liquids (68 data sets in total) are analyzed and shown to exhibit a remarkable degree of universality. In particular, super-Arrhenius behaviors of all super-cooled liquids appear to collapse to one parabola for which there is no singular behavior at any finite temperature. This behavior is bounded by an onset temperature To above which liquid transport has a much weaker temperature dependence. A similar collapse is also demonstrated, over the smaller available range, for existing numerical simulation data.Comment: 6 pages, 2 figures. Updated References, Table Values, Submitted for Publicatio

    Statistical Mechanics of Glass Formation in Molecular Liquids with OTP as an Example

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    We extend our statistical mechanical theory of the glass transition from examples consisting of point particles to molecular liquids with internal degrees of freedom. As before, the fundamental assertion is that super-cooled liquids are ergodic, although becoming very viscous at lower temperatures, and are therefore describable in principle by statistical mechanics. The theory is based on analyzing the local neighborhoods of each molecule, and a statistical mechanical weight is assigned to every possible local organization. This results in an approximate theory that is in very good agreement with simulations regarding both thermodynamical and dynamical properties

    Globalization, multinationals and institutional diversity

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    This article aims to explore the impact of globalization and in particular multinationals on diversity within national varieties of capitalism. Do the actions of multinationals create more diversity within national systems, do they reduce diversity or do they have relatively little impact on diversity within national systems? The article argues that there are distinctive structures of institutional diversity across different national systems. Therefore, the question is not how do MNCs impact on institutional diversity per se but how do they impact on these different structures of diversity? In order to develop this argument, the paper also differentiates types of multinational. The article uses distinction between market-seeking, resource-seeking, efficiency-seeking and strategic asset-seeking in order to identify a range of different MNC activity across manufacturing, professional and financial sectors. These different sorts of MNC activity vary across time and contexts in terms of their significance. The article looks in detail at four different models of capitalism and examines how the entry of different sorts of multinationals with distinctive objectives impacts on the relationships between key social actors which underpin and reinforce these models. In this way, it suggests how institutional diversity within different types of capitalism may evolve under the impact of MNCs and globalization

    The EndoC-βH1 cell line is a valid model of human beta cells and applicable for screenings to identify novel drug target candidates

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    Objective: To characterize the EndoC-βH1 cell line as a model for human beta cells and evaluate its beta cell functionality, focusing on insulin secretion, proliferation, apoptosis and ER stress, with the objective to assess its potential as a screening platform for identification of novel anti-diabetic drug candidates. Methods: EndoC-βH1 was transplanted into mice for validation of in vivo functionality. Insulin secretion was evaluated in cells cultured as monolayer and as pseudoislets, as well as in diabetic mice. Cytokine induced apoptosis, glucolipotoxicity, and ER stress responses were assessed. Beta cell relevant mRNA and protein expression were investigated by qPCR and antibody staining. Hundreds of proteins or peptides were tested for their effect on insulin secretion and proliferation. Results: Transplantation of EndoC-βH1 cells restored normoglycemia in streptozotocin induced diabetic mice. Both in vitro and in vivo, we observed a clear insulin response to glucose, and, in vitro, we found a significant increase in insulin secretion from EndoC-βH1 pseudoislets compared to monolayer cultures for both glucose and incretins.Apoptosis and ER stress were inducible in the cells and caspase 3/7 activity was elevated in response to cytokines, but not affected by the saturated fatty acid palmitate.By screening of various proteins and peptides, we found Bombesin (BB) receptor agonists and Pituitary Adenylate Cyclase-Activating Polypeptides (PACAP) to significantly induce insulin secretion and the proteins SerpinA6, STC1, and APOH to significantly stimulate proliferation.ER stress was readily induced by Tunicamycin and resulted in a reduction of insulin mRNA. Somatostatin (SST) was found to be expressed by 1% of the cells and manipulation of the SST receptors was found to significantly affect insulin secretion. Conclusions: Overall, the EndoC-βH1 cells strongly resemble human islet beta cells in terms of glucose and incretin stimulated insulin secretion capabilities. The cell line has an active cytokine induced caspase 3/7 apoptotic pathway and is responsive to ER stress initiation factors. The cells' ability to proliferate can be further increased by already known compounds as well as by novel peptides and proteins. Based on its robust performance during the functionality assessment assays, the EndoC-βH1 cell line was successfully used as a screening platform for identification of novel anti-diabetic drug candidates. Keywords: EndoC-βH1, Pseudoislets, Glucose stimulated insulin secretion, Somatostatin signaling, Proliferatio

    Impaired Spleen Formation Perturbs Morphogenesis of the Gastric Lobe of the Pancreas

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    Despite the extensive use of the mouse as a model for studies of pancreas development and disease, the development of the gastric pancreatic lobe has been largely overlooked. In this study we use optical projection tomography to provide a detailed three-dimensional and quantitative description of pancreatic growth dynamics in the mouse. Hereby, we describe the epithelial and mesenchymal events leading to the formation of the gastric lobe of the pancreas. We show that this structure forms by perpendicular growth from the dorsal pancreatic epithelium into a distinct lateral domain of the dorsal pancreatic mesenchyme. Our data support a role for spleen organogenesis in the establishment of this mesenchymal domain and in mice displaying perturbed spleen development, including Dh +/−, Bapx1−/− and Sox11−/−, gastric lobe development is disturbed. We further show that the expression profile of markers for multipotent progenitors is delayed in the gastric lobe as compared to the splenic and duodenal pancreatic lobes. Altogether, this study provides new information regarding the developmental dynamics underlying the formation of the gastric lobe of the pancreas and recognizes lobular heterogeneities regarding the time course of pancreatic cellular differentiation. Collectively, these data are likely to constitute important elements in future interpretations of the developing and/or diseased pancreas

    Integrated Brain Atlas for Unbiased Mapping of Nervous System Effects Following Liraglutide Treatment

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    Light Sheet Fluorescence Microscopy (LSFM) of whole organs, in particular the brain, offers a plethora of biological data imaged in 3D. This technique is however often hindered by cumbersome non-Automated analysis methods. Here we describe an approach to fully automate the analysis by integrating with data from the Allen Institute of Brain Science (AIBS), to provide precise assessment of the distribution and action of peptide-based pharmaceuticals in the brain. To illustrate this approach, we examined the acute central nervous system effects of the glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide. Peripherally administered liraglutide accessed the hypothalamus and brainstem, and led to activation in several brain regions of which most were intersected
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