355 research outputs found

    Effect of the activator dose on the compressive strength and accelerated carbonation resistance of alkali silicate-activated slag/metakaolin blended materials

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    The effects of activator dose on the properties of alkali-activated slag/metakaolin blends, were studied in fresh and hardened states: heat evolution, strength and accelerated carbonation. High activator concentrations affect the slag dissolution rate, reducing compressive strength when this is the sole precursor. An increased activator concentration favours metakaolin reaction, promoting high strengths and reduced permeability. Metakaolin addition, and increased activator concentrations reduce the susceptibility to carbonation, associated with the refinement of the pore network under extended CO2 exposure. The effect of adding an aluminosilicate precursor to an alkali-activated slag system is strongly dependent on the activator concentration

    PDE problems with concentrating terms near the boundary

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    In this paper we study several PDE problems where certain linear or nonlinear termsin the equation concentrate in the domain, typically (but not exclusively) near the boundary. We analyze some linear and nonlinear elliptic models, linear and nonlinear parabolic ones as well as some damped wave equations. We show that in all these singularly perturbed problems, the concentrating terms give rise in the limit to a modification in the original boundary condition of the problem. Hence we describe in each case which is the singular limit problem and analyze the convergence of solutions

    Structure-function dissection of Myxococcus xanthus CarD N-terminal domain, a defining member of the CarD-CdnL-TRCF family of RNA polymerase interacting proteins

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    © 2015 Bernal-Bernal et al. Two prototypes of the large CarD-CdnL-TRCF family of bacterial RNA polymerase (RNAP)-binding proteins, Myxococcus xanthus CarD and CdnL, have distinct functions whose molecular basis remain elusive. CarD, a global regulator linked to the action of several extracytoplasmic function (ECF) σ-factors, binds to the RNAP β subunit (RNAP-β) and to protein CarG via an N-terminal domain, CarDNt, and to DNA via an intrinsically unfolded C-terminal domain resembling eukaryotic high-mobility-group A (HMGA) proteins. CdnL, a CarDNt-like protein that is essential for cell viability, is implicated in σA-dependent rRNA promoter activation and interacts with RNAP-β but not with CarG. While the HMGA-like domain of CarD by itself is inactive, we find that CarDNt has low but observable ability to activate ECF σ-dependent promoters in vivo, indicating that the C-terminal DNA-binding domain is required to maximize activity. Our structure-function dissection of CarDNt reveals an N-terminal, five-stranded β-sheet Tudor-like domain, CarD1-72, whose structure and contacts with RNAP-β mimic those of CdnL. Intriguingly, and in marked contrast to CdnL, CarD mutations that disrupt its interaction with RNAP-β did not annul activity. Our data suggest that the CarDNt C-terminal segment, CarD61-179, may be structurally distinct from its CdnL counterpart, and that it houses at least two distinct and crucial function determinants: (a) CarG-binding, which is specific to CarD; and (b) a basic residue stretch, which is also conserved and functionally required in CdnL. This study highlights the evolution of shared and divergent interactions in similar protein modules that enable the distinct activities of two related members of a functionally important and widespread bacterial protein family.Peer Reviewe

    Thermodynamic modelling of phase evolution in alkali-activated slag cements exposed to carbon dioxide

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    Carbonation of cementitious materials induced by their interaction with atmospheric CO2 is one of the main degradation mechanisms threatening their durability. In this study, a novel thermodynamic model to predict the phase evolution of alkali-activated slags exposed to an accelerated carbonation environment is presented. This model predicts the phase assemblages of carbonated alkali-activated slag cements, as a function of CO2 uptake under 1 v/v % CO2 conditions, considering the bulk slag chemistry and activators used. The changes taking place during the carbonation process regarding the physicochemical properties of the main binding gel, an alkali calcium aluminosilicate hydrate (C-(N)-A-S-H), the secondary reaction products CaAl and MgAl layered double hydroxides, and amorphous aluminosilicate gels, were simulated and discussed. The predictions of the thermodynamic model are in good agreement with experimental data retrieved from the literature, demonstrating that this is a valuable tool for predicting long-term performance of alkali-activated slag cements

    Toward a clinical practice guide in pharmacogenomics testing for functional polymorphisms of drug-metabolizing enzymes. Gene/drug pairs and barriers perceived in Spain

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    The development of clinica lpractice recommendations or guidelines for the clinical use of biomarkers is an issue of great importance withr regard to adverse drug reactions.The poten-tial of pharmacogenomicbiomarkers has been extensively investigated in recent years.However,several barriers to implementing the use of pharmacogenomics testing exist.We conducted a survey among members of the Spanish Societies of Pharmacology and Clinical Pharmacology to obtain information about the perception of such barriers and to compare the perceptions of participants about the relative importance of majorgene/drug pairs.Of 11 potential barriers,the highest importance was attributed to lack of institutional support for pharmacogenomic stesting,and to the issues related to the lack of guidelines.Of the proposed gene/drug pairs the highest importance was assigned to HLA-B/abacavir, UGT1A1/irinotecan, and CYP2D6/tamoxifen.In this perspective article,we compare the relative importance of 29 gene/drugpairs in the Spanish study with that of the same pairs in the American Society for Clinical Pharmacology and Therapeutic sstudy,and we provide suggestions and areas of focus to develop a guide for clinical practice in pharmacogenomics testingThe work in the author’s laboratory is financed by Grants PS09/00943, PS09/00469, RETICS RIRAAF RD07/0064/0016, and CIBERehd from Instituto de Salud CarlosIII,Madrid, Spain, and by Grants GR10068 from Junta de Extremadura, Spain. Financed in part with FEDER funds from the European Unio

    Association of Adherence to Specific Mediterranean Diet Components and Cardiorespiratory Fitness in Young Adults

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    Objective: Cardiorespiratory fitness (CRF) and a healthy diet may be part of an overall healthy lifestyle. The association between cardiorespiratory fitness and adherence to an overall Mediterranean Diet (MedD) pattern and specific MedD foods has been assessed. Design: Subjects completed a lifestyle survey and dietary pattern, using the validated MedD Adherence 14-item questionnaire and two self-reported 24-h dietary recalls. Participants' height, body weight, waist circumference (WC), and CRF (maximum oxygen uptake, VO2max, ml/kg/min) were measured. Setting: University of Cadiz, Spain. Subjects: A sample of young adults (n = 275, 22.2 +/- 6.3 years). Results: Mean VO2max was 43.9 mL/kg/min (SD 8.5 mL/kg/min). Most participants had healthy CRF (75.9%). The average MedD score was 6.2 points (SD 1.8 points). Participants who consumed more servings of nuts had higher VO2max. Those who showed low CRF performed less physical activity (PA) and had a higher body mass index (BMI) and WC compared with those classified as having healthy CRF. Nut consumption was positively associated with VO2max (beta = 0.320; 95% CI 2.4, 10.7; p < 0.002), adjusting for sex, age, smoking PA, BMI, WC, and energy intake, showing the subjects who consumed more nuts were fitter than young adults who consumed less. Conclusions: CRF is positively associated with nut consumption but not with the overall MedD pattern and all other MedD foods in the young adults. The subjects who consumed more servings of nuts were fitter than young adults who consumed less. Moreover, fitter subjects performed more PA and had a lower BMI and WC than those who had lower fitness levels

    Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste

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    The properties and microstructure of alkali-activated (AA) vitreous calcium aluminosilicate (VCAS) are presented in this paper. VCAS is manufactured from a by-product of the glass fiber industry and has been activated using NaOH and KOH solutions. The microstructure and mechanical properties of AA VCAS pastes and mortars are reported. The results show that depending on the type and concentration of hydroxide solution used, mortar samples with compressive strengths up to 77 MPa can be formed after curing for three days at 65 °C. The research demonstrates the potential of VCAS to produce AA cements and the importance of alkali type and concentration in optimizing properties and microstructure.Mitsuuchi Tashima, M.; Soriano Martinez, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Cheeseman, CR.; Paya Bernabeu, JJ. (2012). Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste. Journal of Sustainable Cement-Based Materials. 1(3):83-93. doi:10.1080/21650373.2012.742610S839313Mahasenan N, Smith S, Humphreys K. The cement industry and global climate change: current and potential future cement industry CO2emissions. Greenhouse Gas Control Technologies – 6th International Conference. Oxford: Pergamon; 2003. p. 995–1000.Schneider, M., Romer, M., Tschudin, M., & Bolio, H. (2011). Sustainable cement production—present and future. Cement and Concrete Research, 41(7), 642-650. doi:10.1016/j.cemconres.2011.03.019WBCSD – World Business Council for Sustainable Development. Cement industry energy and CO2performance – Getting numbers right. Edited by WBCSD, Geneva-Switzerland (ISBN 978-3-940388-48-3). 2009.Shi, C., Jiménez, A. F., & Palomo, A. (2011). New cements for the 21st century: The pursuit of an alternative to Portland cement. Cement and Concrete Research, 41(7), 750-763. doi:10.1016/j.cemconres.2011.03.016Duxson, P., Fernández-Jiménez, A., Provis, J. L., Lukey, G. C., Palomo, A., & van Deventer, J. S. J. (2006). Geopolymer technology: the current state of the art. Journal of Materials Science, 42(9), 2917-2933. doi:10.1007/s10853-006-0637-zFernández-Jiménez, A., Palomo, A., & Criado, M. (2005). Microstructure development of alkali-activated fly ash cement: a descriptive model. Cement and Concrete Research, 35(6), 1204-1209. doi:10.1016/j.cemconres.2004.08.021Hossain, A. B., Shirazi, S. A., Persun, J., & Neithalath, N. (2008). Properties of Concrete Containing Vitreous Calcium Aluminosilicate Pozzolan. Transportation Research Record: Journal of the Transportation Research Board, 2070(1), 32-38. doi:10.3141/2070-05Neithalath, N., Persun, J., & Hossain, A. (2009). Hydration in high-performance cementitious systems containing vitreous calcium aluminosilicate or silica fume. Cement and Concrete Research, 39(6), 473-481. doi:10.1016/j.cemconres.2009.03.006Tashima MM, Soriano L, Borrachero MV, Monzó J, Payá J. Effect of curing time on the microstructure and mechanical strength development of alkali activated nbinders based on vitreous calcium aluminosilicate (VCAS). Bull. Mater. Sci. in press.Hemmings RT, Nelson RD, Graves PL, Cornelius BJ. White pozzolan composition and blended cements containing same. Patent US6776838. 2004.Provis, J. L., Lukey, G. C., & van Deventer, J. S. J. (2005). Do Geopolymers Actually Contain Nanocrystalline Zeolites? A Reexamination of Existing Results. Chemistry of Materials, 17(12), 3075-3085. doi:10.1021/cm050230iCriado, M., Fernández-Jiménez, A., de la Torre, A. G., Aranda, M. A. G., & Palomo, A. (2007). An XRD study of the effect of the SiO2/Na2O ratio on the alkali activation of fly ash. Cement and Concrete Research, 37(5), 671-679. doi:10.1016/j.cemconres.2007.01.013Rees, C. A., Provis, J. L., Lukey, G. C., & van Deventer, J. S. J. (2007). In Situ ATR-FTIR Study of the Early Stages of Fly Ash Geopolymer Gel Formation. Langmuir, 23(17), 9076-9082. doi:10.1021/la701185gLee, W. K. W., & van Deventer, J. S. J. (2003). Use of Infrared Spectroscopy to Study Geopolymerization of Heterogeneous Amorphous Aluminosilicates. Langmuir, 19(21), 8726-8734. doi:10.1021/la026127eGarcía-Lodeiro, I., Fernández-Jiménez, A., Blanco, M. T., & Palomo, A. (2007). FTIR study of the sol–gel synthesis of cementitious gels: C–S–H and N–A–S–H. Journal of Sol-Gel Science and Technology, 45(1), 63-72. doi:10.1007/s10971-007-1643-6Barbosa VFF. Sintese e caracterização de polissialatos (Synthesis and characterization of polysialates) [PhD thesis] (in Portuguese). Instituto Militar de Engenharia. Rio de Janeiro - Brazil. 190 p. 1999.Bernal, S. A., Rodríguez, E. D., Mejía de Gutiérrez, R., Gordillo, M., & Provis, J. L. (2011). Mechanical and thermal characterisation of geopolymers based on silicate-activated metakaolin/slag blends. Journal of Materials Science, 46(16), 5477-5486. doi:10.1007/s10853-011-5490-zBoccaccini, A. R., Bücker, M., Bossert, J., & Marszalek, K. (1997). Glass matrix composites from coal flyash and waste glass. Waste Management, 17(1), 39-45. doi:10.1016/s0956-053x(97)00035-4Kourti, I., Rani, D. A., Deegan, D., Boccaccini, A. R., & Cheeseman, C. R. (2010). Production of geopolymers using glass produced from DC plasma treatment of air pollution control (APC) residues. Journal of Hazardous Materials, 176(1-3), 704-709. doi:10.1016/j.jhazmat.2009.11.089Lampris, C., Lupo, R., & Cheeseman, C. R. (2009). Geopolymerisation of silt generated from construction and demolition waste washing plants. Waste Management, 29(1), 368-373. doi:10.1016/j.wasman.2008.04.007Wu, H.-C., & Sun, P. (2007). New building materials from fly ash-based lightweight inorganic polymer. Construction and Building Materials, 21(1), 211-217. doi:10.1016/j.conbuildmat.2005.06.052Kourti, I., Amutha Rani, D., Boccaccini, A. R., & Cheeseman, C. R. (2011). Geopolymers from DC Plasma–Treated Air Pollution Control Residues, Metakaolin, and Granulated Blast Furnace Slag. Journal of Materials in Civil Engineering, 23(6), 735-740. doi:10.1061/(asce)mt.1943-5533.000017

    Lifestyle and Treatment Adherence Intervention after a Coronary Event Based on an Interactive Web Application (EVITE): Randomized Controlled Clinical Trial Protocol

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    Coronary heart disease is one of the main causes of morbimortality around the world. Patients that survive a coronary event suffer a high risk of readmission, relapse and mortality, attributed to the sub-optimal control of cardiovascular risk factors (CVRF), which highlights the need to improve secondary prevention strategies aimed at improving their lifestyle and adherence to treatment. Through a randomized controlled clinical trial, this study aims to evaluate the effect of an intervention involving an online health application supported by a mobile telephone or tablet (mHealth) on lifestyle (diet, physical activity, and tobacco consumption) and treatment adherence among people with coronary heart disease after percutaneous coronary intervention. The sample will comprise 240 subjects (120 in each arm: intervention and usual care). They are assessed immediately and nine months after their hospital discharge about sociodemographic, clinical, CVRF, lifestyle, and treatment adherence characteristics. The educative intervention, involving a follow-up and self-monitoring, will be performed using an online mHealth tool consisting of an application for mobile phones and tablets. The quantitative primary outcomes from the two groups will be compared using an analysis of covariance (ANCOVA) adjusted for age and gender. A multivariate analysis will be performed to examine the association of the intervention with lifestyle habits, the control of CVRFs, and outcomes after discharge in terms of the use of health services, emergency visits, cardiovascular events and readmissions.Andalusian Ministry of Health and Families, Spain. Public funding. PI-0067-2018. JA Tur is funded by CIBEROBN (CB12/03/30038)-Instituto de Salud Carlos III and cofunded by the European Regional Development Fund

    Evaluación de granos agrícolas para la elaboración artesanal de inoculo de <i>ganoderma lucidum</i>

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    Los hongos son organismos que se encuentran en todos los biomas y sobre los más variados sustratos. Se estima que se conoce 5% del total de los hongos existentes en el planeta y que están involucrados en la desintegración de la materia orgánica, procesos industriales de fermentación, producción comercial de alimentos y medicamentos, así mismo, en los sistemas agroforestales. Dentro de los hongos medicinales se encuentra, Ganoderma lucidum que ocupa los primeros lugares en China, dado que se lo utiliza para elaboración de productos artesanales, con fines curativos. Este hongo presenta una gran demanda en el mercado internacional y no existe un sistema de cultivo que brinde las condiciones óptimas para su producción. El objetivo del presente trabajo fue evaluar las características organolépticas del inoculo de Ganoderma lucidum en 60 días de producción, con sustratos a base de maíz quebrado, grano de trigo y olote de maíz en diferentes proporciones. Los resultados mostraron que la mejor adición de sustrato, es el grano de trigo; pero el tratamiento a base de maíz quebrado y olote de maíz (parte central de la mazorca una vez que ha perdido los granos) confiere un buen desarrollo en la estimación de la biomasa, aportando un 100 % de colonización con agradable aroma y nula contaminación, mostrando que es posible su empleo para la producción de Ganoderma lucidum a nivel artesanal.Fungi are organisms present on all biomes in a wide variety of substrates. It is estimated that 5% of all existing fungi are known and they are involved in organic disintegration, industrial fermetation processes, comercial production in food and medicine, on the same way in agroforestry systems. Among medicinal mushrooms is, Ganoderma lucidum which occupies first place in China, since it is used for making handicrafts, for medicinal purposes. This fungus has a high demand and not there is a culture system that provides the optimum conditions for production. The aim of this study was to evaluate the organoleptic characteristics of inoculum of Ganoderma lucidum in 60 days of production in substrates based to cracked corn, wheat grain and corn cob in different proportions. The results showed that the best addition of substrate, is the grain of wheat; but the treatment with cracked corn and corn cob, he developed a good estimate of biomass, providing 100% of colonization with pleasant aroma and no pollution, showing that it is possible to use this substrate for the production of Ganoderma lucidum at the artisanal level.Eje A5: Sistemas de conocimientoFacultad de Ciencias Agrarias y Forestale

    Wide binaries as a critical test of Classical Gravity

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    Modified gravity scenarios where a change of regime appears at acceleration scales a<a0a<a_{0} have been proposed. Since for 1M1 M_{\odot} systems the acceleration drops below a0a_{0} at scales of around 7000 AU, a statistical survey of wide binaries with relative velocities and separations reaching 10410^{4} AU and beyond should prove useful to the above debate. We apply the proposed test to the best currently available data. Results show a constant upper limit to the relative velocities in wide binaries which is independent of separation for over three orders of magnitude, in analogy with galactic flat rotation curves in the same a<a0a<a_{0} acceleration regime. Our results are suggestive of a breakdown of Kepler's third law beyond aa0a \approx a_{0} scales, in accordance with generic predictions of modified gravity theories designed not to require any dark matter at galactic scales and beyond.Comment: accepted for publication in EPJ
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