558 research outputs found

    On the structure and evolution of planets and their host stars - effects of various heating mechanisms on the size of giant gas planets

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    It is already stated in the previous studies that the radius of the giant planets is affected by stellar irradiation. The confirmed relation between radius and incident flux depends on planetary mass intervals. In this study, we show that there is a single relation between radius and irradiated energy per gram per second (ll_-), for all mass intervals. There is an extra increase in radius of planets if ll_- is higher than 1100 times energy received by the Earth (ll_\oplus). This is likely due to dissociation of molecules. The tidal interaction as a heating mechanism is also considered and found that its maximum effect on the inflation of planets is about 15 per cent. We also compute age and heavy element abundances from the properties of host stars, given in the TEPCat catalogue (Southworth 2011). The metallicity given in the literature is as [Fe/H]. However, the most abundant element is oxygen, and there is a reverse relation between the observed abundances [Fe/H] and [O/Fe]. Therefore, we first compute [O/H] from [Fe/H] by using observed abundances, and then find heavy element abundance from [O/H]. We also develop a new method for age determination. Using the ages we find, we analyse variation of both radius and mass of the planets with respect to time, and estimate the initial mass of the planets from the relation we derive for the first time. According to our results, the highly irradiated gas giants lose 5 per cent of their mass in every 1 Gyr.Comment: 15 pages, 13 figures, 3 tables. Accepted by MNRA

    Shapiro and parametric resonances in coupled Josephson junctions

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    The effect of microwave irradiation on the phase dynamics of intrinsic Josephson junctions in high temperature superconductors is investigated. We compare the current-voltage characteristics for a stack of coupled Josephson junctions under external irradiation calculated in the framework of CCJJ and CCJJ+DC models.Comment: 4 pages, Manuscript for Dubna-Nano 2012, submitted for Journal of Physics:Conference Serie

    Electrospun Oxygen Scavenging Films of Poly(3-hydroxybutyrate) Containing Palladium Nanoparticles for Active Packaging Applications

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    [EN] This paper reports on the development and characterization of oxygen scavenging films made of poly(3-hydroxybutyrate) (PHB) containing palladium nanoparticles (PdNPs) prepared by electrospinning followed by annealing treatment at 160 degrees C. The PdNPs were modified with the intention to optimize their dispersion and distribution in PHB by means of two different surfactants permitted for food contact applications, i.e., hexadecyltrimethylammonium bromide (CTAB) and tetraethyl orthosilicate (TEOS). Analysis of the morphology and characterization of the chemical, thermal, mechanical, and water and limonene vapor barrier properties and the oxygen scavenging capacity of the various PHB materials were carried out. From the results, it was seen that a better dispersion and distribution was obtained using CTAB as the dispersing aid. As a result, the PHB/PdNP nanocomposites containing CTAB provided also the best oxygen scavenging performance. These films offer a significant potential as new active coating or interlayer systems for application in the design of novel active food packaging structures.This research has received funding from the Spanish Ministry of Economy and Competitiveness (MINECO, project AGL2015-63855-C2-1-R) and the EU H2020 project YPACK (reference number 773872). A.C. and S.T.-G. would like to thank the Brazilian Council for Scientific and Technological Development (CNPq) and MINECO for her predoctoral grant (205955/2014-2) and his Juan de la Cierva contract (IJCI-2016-29675), respectively.Cherpinski, A.; Gozutok, M.; Turkoglu Sasmazel, H.; Torres-Giner, S.; Lagaron, JM. (2018). Electrospun Oxygen Scavenging Films of Poly(3-hydroxybutyrate) Containing Palladium Nanoparticles for Active Packaging Applications. Nanomaterials. 8(7):1-19. https://doi.org/10.3390/nano8070469S11987Puglia, D., Fortunati, E., D’Amico, D. A., Manfredi, L. B., Cyras, V. P., & Kenny, J. M. (2014). Influence of organically modified clays on the properties and disintegrability in compost of solution cast poly(3-hydroxybutyrate) films. Polymer Degradation and Stability, 99, 127-135. doi:10.1016/j.polymdegradstab.2013.11.013Ma, P., Xu, P., Chen, M., Dong, W., Cai, X., Schmit, P., … Lemstra, P. J. (2014). Structure–property relationships of reactively compatibilized PHB/EVA/starch blends. Carbohydrate Polymers, 108, 299-306. doi:10.1016/j.carbpol.2014.02.058Molinaro, S., Cruz Romero, M., Boaro, M., Sensidoni, A., Lagazio, C., Morris, M., & Kerry, J. (2013). Effect of nanoclay-type and PLA optical purity on the characteristics of PLA-based nanocomposite films. Journal of Food Engineering, 117(1), 113-123. doi:10.1016/j.jfoodeng.2013.01.021Imre, B., & Pukánszky, B. (2013). Compatibilization in bio-based and biodegradable polymer blends. European Polymer Journal, 49(6), 1215-1233. doi:10.1016/j.eurpolymj.2013.01.019Bittmann, B., Bouza, R., Barral, L., Diez, J., & Ramirez, C. (2013). Poly(3-hydroxybutyrate-co -3-hydroxyvalerate)/clay nanocomposites for replacement of mineral oil based materials. Polymer Composites, 34(7), 1033-1040. doi:10.1002/pc.22510Castro-Mayorga, J. L., Fabra, M. J., & Lagaron, J. M. (2016). Stabilized nanosilver based antimicrobial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanocomposites of interest in active food packaging. Innovative Food Science & Emerging Technologies, 33, 524-533. doi:10.1016/j.ifset.2015.10.019Bartczak, Z., Galeski, A., Kowalczuk, M., Sobota, M., & Malinowski, R. (2013). Tough blends of poly(lactide) and amorphous poly([R,S]-3-hydroxy butyrate) – morphology and properties. European Polymer Journal, 49(11), 3630-3641. doi:10.1016/j.eurpolymj.2013.07.033Furukawa, T., Sato, H., Murakami, R., Zhang, J., Duan, Y.-X., Noda, I., … Ozaki, Y. (2005). Structure, Dispersibility, and Crystallinity of Poly(hydroxybutyrate)/Poly(l-lactic acid) Blends Studied by FT-IR Microspectroscopy and Differential Scanning Calorimetry. Macromolecules, 38(15), 6445-6454. doi:10.1021/ma0504668Zhang, M., & Thomas, N. L. (2011). Blending polylactic acid with polyhydroxybutyrate: The effect on thermal, mechanical, and biodegradation properties. Advances in Polymer Technology, 30(2), 67-79. doi:10.1002/adv.20235Yildirim, S., Röcker, B., Rüegg, N., & Lohwasser, W. (2015). Development of Palladium-based Oxygen Scavenger: Optimization of Substrate and Palladium Layer Thickness. Packaging Technology and Science, 28(8), 710-718. doi:10.1002/pts.2134Cernohorsky, O., Zdansky, K., Zavadil, J., Kacerovsky, P., & Piksova, K. (2011). Palladium nanoparticles on InP for hydrogen detection. Nanoscale Research Letters, 6(1). doi:10.1186/1556-276x-6-410Damaj, Z., Joly, C., & Guillon, E. (2014). Toward New Polymeric Oxygen Scavenging Systems: Formation of Poly(vinyl alcohol) Oxygen Scavenger Film. Packaging Technology and Science, 28(4), 293-302. doi:10.1002/pts.2112Torres-Giner, S., Pérez-Masiá, R., & Lagaron, J. M. (2016). A review on electrospun polymer nanostructures as advanced bioactive platforms. Polymer Engineering & Science, 56(5), 500-527. doi:10.1002/pen.24274Echegoyen, Y., Fabra, M. J., Castro-Mayorga, J. L., Cherpinski, A., & Lagaron, J. M. (2017). High throughput electro-hydrodynamic processing in food encapsulation and food packaging applications: Viewpoint. Trends in Food Science & Technology, 60, 71-79. doi:10.1016/j.tifs.2016.10.019Dainelli, D., Gontard, N., Spyropoulos, D., Zondervan-van den Beuken, E., & Tobback, P. (2008). Active and intelligent food packaging: legal aspects and safety concerns. Trends in Food Science & Technology, 19, S103-S112. doi:10.1016/j.tifs.2008.09.011Kundu, S. (2013). A new route for the formation of Au nanowires and application of shape-selective Au nanoparticles in SERS studies. J. Mater. Chem. C, 1(4), 831-842. doi:10.1039/c2tc00315eMayer, A., & Antonietti, M. (1998). Investigation of polymer-protected noble metal nanoparticles by transmission electron microscopy: control of particle morphology and shape. Colloid & Polymer Science, 276(9), 769-779. doi:10.1007/s003960050309Cherpinski, A., Torres-Giner, S., Cabedo, L., & Lagaron, J. M. (2017). Post-processing optimization of electrospun submicron poly(3-hydroxybutyrate) fibers to obtain continuous films of interest in food packaging applications. Food Additives & Contaminants: Part A, 34(10), 1817-1830. doi:10.1080/19440049.2017.1355115Tekmen, C., Tsunekawa, Y., & Nakanishi, H. (2010). Electrospinning of carbon nanofiber supported Fe/Co/Ni ternary alloy nanoparticles. Journal of Materials Processing Technology, 210(3), 451-455. doi:10.1016/j.jmatprotec.2009.10.006Sainudeen, S. S., Asok, L. B., Varghese, A., Nair, A. S., & Krishnan, G. (2017). Surfactant-driven direct synthesis of a hierarchical hollow MgO nanofiber–nanoparticle composite by electrospinning. 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Incorporation of palladium nanoparticles into aromatic polyamide/clay nanocomposites through facile dry route. Polymer Science Series B, 57(4), 380-386. doi:10.1134/s1560090415040120Yeo, S. Y., Tan, W. L., Abu Bakar, M., & Ismail, J. (2010). Silver sulfide/poly(3-hydroxybutyrate) nanocomposites: Thermal stability and kinetic analysis of thermal degradation. Polymer Degradation and Stability, 95(8), 1299-1304. doi:10.1016/j.polymdegradstab.2010.02.025Díez-Pascual, A., & Díez-Vicente, A. (2014). Poly(3-hydroxybutyrate)/ZnO Bionanocomposites with Improved Mechanical, Barrier and Antibacterial Properties. International Journal of Molecular Sciences, 15(6), 10950-10973. doi:10.3390/ijms150610950Torres-Giner, S., Montanes, N., Boronat, T., Quiles-Carrillo, L., & Balart, R. (2016). Melt grafting of sepiolite nanoclay onto poly(3-hydroxybutyrate-co-4-hydroxybutyrate) by reactive extrusion with multi-functional epoxy-based styrene-acrylic oligomer. 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    A novel treatment strategy for preterm birth: Intra-vaginal progesterone-loaded fibrous patches

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    Progesterone-loaded poly(lactic) acid fibrous polymeric patches were produced using electrospinning and pressurized gyration for intra-vaginal application to prevent preterm birth. The patches were intravaginally inserted into rats in the final week of their pregnancy, equivalent to the third trimester of human pregnancy. Maintenance tocolysis with progesterone-loaded patches was elucidated by recording the contractile response of uterine smooth muscle to noradrenaline in pregnant rats. Both progesterone-loaded patches indicated similar results from release and thermal studies, however, patches obtained by electrospinning had smaller average diameters and more uniform dispersion compared to pressurized gyration. Patches obtained by pressurized gyration had better results in production yield and tensile strength than electrospinning; thereby pressurized gyration is better suited for scaled-up production. The patches did not affect cell attachment, viability, and proliferation on Vero cells negatively. Consequently, progesterone-loaded patches are a novel and successful treatment strategy for preventing preterm birth

    Manifestation of Resonance-Related Chaos in Coupled Josephson Junctions

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    Chaotic features of systems of coupled Josephson junctions are studied. Manifestation of chaos in the temporal dependence of the electric charge, related to a parametric resonance, is demonstrated through the calculation of the maximal Lyapunov exponent, phase-charge and charge-charge Lissajous diagrams and correlation functions. The number of junctions in the stack strongly influences the fine structure in the current voltage characteristics and a strong proximity effect results from the nonperiodic boundary conditions. The observed resonance-related chaos exhibits intermittency over a range of conditions and parameters. General features of the system are analyzed by means of a linearized equation and the criteria for a breakpoint region with no chaos are obtained. Such criteria could clarify recent experimental observations of variations in the power output from intrinsic Josephson junctions in high temperature superconductors.Comment: 13 pages, 16 figure

    Characterisation and mechanical modelling of polyacrylonitrile-based nanocomposite membranes reinforced with silica nanoparticles

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    In this study, neat polyacrylonitrile (PAN) and fumed silica (FS)-doped PAN membranes (0.1, 0.5 and 1 wt% doped PAN/FS) are prepared using the phase inversion method and are characterised extensively. According to the Fourier Transform Infrared (FTIR) spectroscopy analysis, the addition of FS to the neat PAN membrane and the added amount changed the stresses in the membrane structure. The Scanning Electron Microscope (SEM) results show that the addition of FS increased the porosity of the membrane. The water content of all fabricated membranes varied between 50% and 88.8%, their porosity ranged between 62.1% and 90%, and the average pore size ranged between 20.1 and 21.8 nm. While the neat PAN membrane’s pure water flux is 299.8 L/m2 h, it increased by 26% with the addition of 0.5 wt% FS. Furthermore, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques are used to investigate the membranes’ thermal properties. Finally, the mechanical characterisation of manufactured membranes is performed experimentally with tensile testing under dry and wet conditions. To be able to provide further explanation to the explored mechanics of the membranes, numerical methods, namely the finite element method and Mori–Tanaka mean-field homogenisation are performed. The mechanical characterisation results show that FS reinforcement increases the membrane rigidity and wet membranes exhibit more compliant behaviour compared to dry membranes

    Investigating the biological properties of carbohydrate derived fulvic acid (CHD-FA) as a potential novel therapy for the management of oral biofilm infections.

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    Background: A number of oral diseases, including periodontitis, derive from microbial biofilms and are associated with increased antimicrobial resistance. Despite the widespread use of mouthwashes being used as adjunctive measures to control these biofilms, their prolonged use is not recommended due to various side effects. Therefore, alternative broad-spectrum antimicrobials that minimise these effects are highly sought after. Carbohydrate derived fulvic acid (CHD-FA) is an organic acid which has previously demonstrated to be microbiocidal against Candida albicans biofilms, therefore, the aims of this study were to evaluate the antibacterial activity of CHD-FA against orally derived biofilms and to investigate adjunctive biological effects.<p></p> Methods: Minimum inhibitory concentrations were evaluated for CHD-FA and chlorhexidine (CHX) against a range of oral bacteria using standardised microdilution testing for planktonic and sessile. Scanning electron microscopy was also employed to visualise changes in oral biofilms after antimicrobial treatment. Cytotoxicity of these compounds was assessed against oral epithelial cells, and the effect of CHD-FA on host inflammatory markers was assessed by measuring mRNA and protein expression.<p></p> Results: CHD-FA was highly active against all of the oral bacteria tested, including Porphyromonas gingivalis, with a sessile minimum inhibitory concentration of 0.5%. This concentration was shown to kill multi-species biofilms by approximately 90%, levels comparable to that of chlorhexidine (CHX). In a mammalian cell culture model, pretreatment of epithelial cells with buffered CHD-FA was shown to significantly down-regulate key inflammatory mediators, including interleukin-8 (IL-8), after stimulation with a multi-species biofilm.<p></p> Conclusions: Overall, CHD-FA was shown to possess broad-spectrum antibacterial activity, with a supplementary function of being able to down-regulate inflammation. These properties offer an attractive spectrum of function from a naturally derived compound, which could be used as an alternative topical treatment strategy for oral biofilm diseases. Further studies in vitro and in vivo are required to determine the precise mechanism by which CHD-FA modulates the host immune response.<p></p&gt

    Visible photoluminescence from SiOx films grown by low temperature plasma enhanced chemical vapor deposition

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    a-SiOx films of varying stoichiometry have been prepared by low temperature plasma enhanced chemical vapor deposition. The majority of films showed photoluminescence (PL) and films prepared in a narrow range of gas flows exhibited much stronger PL after annealing. Peak PL energies ranging from the ultraviolet to the near infrared have been observed. PL, infrared and X-ray diffraction on selected samples indicate formation of Si clusters in the films. The effects of annealing on the PL properties of the films have been found to depend on initial stoichiometry of the films. © 1995

    Mitochondrial carrier homolog 1 (Mtch1) antibodies in neuro-Behçet's disease

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    Cataloged from PDF version of article.Efforts for the identification of diagnostic autoantibodies for neuro-Behcet's disease (NBD) have failed. Screening of NBD patients' sera with protein macroarray identified mitochondrial carrier homolog 1 (Mtch1), an apoptosis-related protein, as a potential autoantigen. ELISA studies showed serum Mtch1 antibodies in 68 of 144 BD patients with or without neurological involvement and in 4 of 168 controls corresponding to a sensitivity of 47.2% and specificity of 97.6%. Mtch1 antibody positive NBD patients had more attacks, increased disability and lower serum nucleosome levels. Mtch1 antibody might be involved in pathogenic mechanisms of NBD rather than being a coincidental byproduct of autoinflammation. © 2013 Elsevier B.V

    First Observation of PP-odd γ\gamma Asymmetry in Polarized Neutron Capture on Hydrogen

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    We report the first observation of the parity-violating 2.2 MeV gamma-ray asymmetry AγnpA^{np}_\gamma in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. AγnpA^{np}_\gamma isolates the ΔI=1\Delta I=1, \mbox{3S13P1^{3}S_{1}\rightarrow {^{3}P_{1}}} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless EFT. We measured Aγnp=[3.0±1.4(stat)±0.2(sys)]×108A^{np}_\gamma = [-3.0 \pm 1.4 (stat) \pm 0.2 (sys)]\times 10^{-8}, which implies a DDH weak πNN\pi NN coupling of hπ1=[2.6±1.2(stat)±0.2(sys)]×107h_{\pi}^{1} = [2.6 \pm 1.2(stat) \pm 0.2(sys)] \times 10^{-7} and a pionless EFT constant of C3S13P1/C0=[7.4±3.5(stat)±0.5(sys)]×1011C^{^{3}S_{1}\rightarrow ^{3}P_{1}}/C_{0}=[-7.4 \pm 3.5 (stat) \pm 0.5 (sys)] \times 10^{-11} MeV1^{-1}. We describe the experiment, data analysis, systematic uncertainties, and the implications of the result.Comment: 6 pages, 5 figure
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