301 research outputs found

    Evaluación funcional en ancianos intervenidos de fractura de cadera

    Get PDF
    Estudio observacional prospectivo en pacientes mayores de 65 años intervenidos de fractura de cadera. El objetivo fue conocer la evolución funcional de los pacientes a los tres meses del alta hospitalaria, identificar variables relacionadas con dicha recuperación funcional, describir la mortalidad e institucionalización asociadas al proceso. Se analizaron variables demográficas como edad, sexo, convivencia. Otros aspectos registrados fueron: comorbilidad, deterioro cognitivo, capacidad para caminar, nivel de dependencia según índice de Barthel, institucionalización y mortalidad. Se recogió la información al ingreso y a los 3 meses del alta. El 89,6% de la muestra, fueron mujeres, la edad media fue de 83,56 años. El 40% de los pacientes recuperaron la independencia previa registrándose una mortalidad del 16,7% así como una leve progresión hacia la institucionalización. La capacidad funcional y el deterioro cognitivo del paciente, previos a la fractura condicionan su recuperación funcional y dependencias posteriores

    Thermal properties comparison of hybrid CF/FF and BF/FF cyanate ester-based composites

    Full text link
    [EN] Insights within thermal expansion, conductivity, and decomposition dependencies with temperature on symmetrical and unsymmetrical layered carbon (CF) or basalt (BF) fabrics in combination with flax fibers (FF) were approached. Driven by commercial application and environmental concerns, the paper draws attention on a modified formula of cyanate ester with a common epoxy resin under an optimized ratio of 70:30 (vol%) as well as on the hybrid reinforcements stacking sequences. Synergetic effects were debated in terms of the CF and BF stacking sequences and corresponding volume fraction followed by comparisons with values predicted by the deployment of hybrid mixtures rules (RoHM/iRoHM). CF hybrid architectures revealed enhanced effective thermophysical properties over their BF counterparts and both over the FF-reinforced polymer composite considered as a reference. Thermal conductivities spread between 0.116 and 0.299 W m-1 K-1 from room temperature up to 250 C on all hybrid specimens, giving rise to an insulator character. Concerning the coefficient of thermal expansion, CF hybrid architectures disclosed values of 1.236 10-6 K-1 and 3.102 10-6 K-1 compared with BF affine exhibiting 4.794 10-6 K-1 and 6.245 10-6 K-1, respectively, with an increase in their volume fraction.The corresponding author gratefully acknowledges the financial assistance of German Academic Exchange Service-DAAD that enabled and supported the internship with Fraunhofer Research Institution for Polymeric Materials and Composites-PYCO, Germany. Many thanks go to Dr. Christian Dreyer and Dr. Maciej Gwiazda for the resin formula and access to the composite manufacturing technology.Motoc, DL.; Ferrándiz Bou, S.; Balart, R. (2018). Thermal properties comparison of hybrid CF/FF and BF/FF cyanate ester-based composites. Journal of Thermal Analysis and Calorimetry. 133(1):509-518. https://doi.org/10.1007/s10973-018-7222-yS5095181331Assarar M, Zouari W, Sabhi H, Ayad R, Berthelot J-M. Evaluation of the damping of hybrid carbon–flax reinforced composites. Compos Struct. 2015;132:148–54.Duc F, Bourban PE, Plummer CJG, Månson JAE. Damping of thermoset and thermoplastic flax fibre composites. Compos A Appl Sci Manuf. 2014;64:115–23.Saba N, Jawaid M, Alothman OY, Paridah MT. A review on dynamic mechanical properties of natural fibre reinforced polymer composites. Constr Build Mater. 2016;106:149–59.Tian H, Zhang S, Ge X, Xiang A. Crystallization behaviors and mechanical properties of carbon fiber-reinforced polypropylene composites. J Therm Anal Calorim. 2017;128(3):1495–504.Alvarez V, Rodriguez E, Vázquez A. Thermaldegradation and decomposition of jute/vinylester composites. J Therm Anal Calorim. 2006;85(2):383–9.Manfredi LB, Rodríguez ES, Wladyka-Przybylak M, Vázquez A. Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres. Polym Degrad Stab. 2006;91(2):255–61.Lazko J, Landercy N, Laoutid F, Dangreau L, Huguet MH, Talon O. Flame retardant treatments of insulating agro-materials from flax short fibres. Polym Degrad Stab. 2013;98(5):1043–51.Bar M, Alagirusamy R, Das A. Flame retardant polymer composites. Fibers Polym. 2015;16(4):705–17.Kollia E, Loutas T, Fiamegkou E, Vavouliotis A, Kostopoulos V. Degradation behavior of glass fiber reinforced cyanate ester composites under hydrothermal ageing. Polym Degrad Stab. 2015;121:200–7.Jawaid M, Abdul Khalil HPS. Cellulosic/synthetic fibre reinforced polymer hybrid composites: a review. Carbohyd Polym. 2011;86(1):1–18.Azwa ZN, Yousif BF, Manalo AC, Karunasena W. A review on the degradability of polymeric composites based on natural fibres. Mater Des. 2013;47:424–42.H-y Cheung, M-p Ho, K-t Lau, Cardona F, Hui D. Natural fibre-reinforced composites for bioengineering and environmental engineering applications. Compos B Eng. 2009;40(7):655–63.Dittenber DB, GangaRao HVS. Critical review of recent publications on use of natural composites in infrastructure. Compos A Appl Sci Manuf. 2012;43(8):1419–29.Faruk O, Bledzki AK, Fink H-P, Sain M. Biocomposites reinforced with natural fibers: 2000–2010. Prog Polym Sci. 2012;37(11):1552–96.Praveen RS, Jacob S, Murthy CRL, Balachandran P, Rao YVKS. Hybridization of carbon–glass epoxy composites: an approach to achieve low coefficient of thermal expansion at cryogenic temperatures. Cryogenics. 2011;51(2):95–104.Jawaid M, Abdul Khalil HPS, Alattas OS. Woven hybrid biocomposites: dynamic mechanical and thermal properties. Compos A Appl Sci Manuf. 2012;43(2):288–93.Swolfs Y, Gorbatikh L, Verpoest I. Fibre hybridisation in polymer composites: a review. Compos A Appl Sci Manuf. 2014;67:181–200.Rojo E, Alonso MV, Oliet M, Del Saz-Orozco B, Rodriguez F. Effect of fiber loading on the properties of treated cellulose fiber-reinforced phenolic composites. Compos B Eng. 2015;68:185–92.LeGault M. Natural fiber composites: market share, one part at the time. Compos World. 2016;5(2):68–75.Joshi SV, Drzal LT, Mohanty AK, Arora S. Are natural fiber composites environmentally superior to glass fiber reinforced composites? Compos A Appl Sci Manuf. 2004;35(3):371–6.Wambua P, Ivens J, Verpoest I. Natural fibres: can they replace glass in fibre reinforced plastics? Compos Sci Technol. 2003;63(9):1259–64.Bertomeu D, García-Sanoguera D, Fenollar O, Boronat T, Balart R. Use of eco-friendly epoxy resins from renewable resources as potential substitutes of petrochemical epoxy resins for ambient cured composites with flax reinforcements. Polym Compos. 2012;33(5):683–92.Alam M, Akram D, Sharmin E, Zafar F, Ahmad S. Vegetable oil based eco-friendly coating materials: a review article. Arab J Chem. 2014;7(4):469–79.Bakare FO, Ramamoorthy SK, Åkesson D, Skrifvars M. Thermomechanical properties of bio-based composites made from a lactic acid thermoset resin and flax and flax/basalt fibre reinforcements. Compos A Appl Sci Manuf. 2016;83:176–84.Pardauil JJR, de Molfetta FA, Braga M, de Souza LKC, Filho GNR, Zamian JR, et al. Characterization, thermal properties and phase transitions of amazonian vegetable oils. J Therm Anal Calorim. 2017;127(2):1221–9.Głowińska E, Datta J, Parcheta P. Effect of sisal fiber filler on thermal properties of bio-based polyurethane composites. J Therm Anal Calorim. 2017;130(1):113–22.Mosiewicki MA, Aranguren MI. A short review on novel biocomposites based on plant oil precursors. Eur Polym J. 2013;49(6):1243–56.Lligadas G, Ronda JC, Galià M, Cádiz V. Renewable polymeric materials from vegetable oils: a perspective. Mater Today. 2013;16(9):337–43.Fombuena V, Sanchez-Nacher L, Samper MD, Juarez D, Balart R. Study of the properties of thermoset materials derived from epoxidized soybean oil and protein fillers. J Am Oil Chem Soc. 2013;90(3):449–57.Pil L, Bensadoun F, Pariset J, Verpoest I. Why are designers fascinated by flax and hemp fibre composites? Compos A Appl Sci Manuf. 2016;83:193–205.Wooster TJ, Abrol S, Hey JM, MacFarlane DR. Thermal, mechanical, and conductivity properties of cyanate ester composites. Compos A Appl Sci Manuf. 2004;35(1):75–82.Mallarino S, Chailan JF, Vernet JL. Glass fibre sizing effect on dynamic mechanical properties of cyanate ester composites I. Single frequency investigations. Eur Polym J. 2005;41(8):1804–11.Sothje D, Dreyer C, Bauer M, editors. Advanced possibilities in thermoset recycling. In: The 3rd international conference on thermosets. 2013; Berlin, Germany.Yuan L, Huang S, Gu A, Liang G, Chen F, Hu Y, et al. A cyanate ester/microcapsule system with low cure temperature and self-healing capacity. Compos Sci Technol. 2013;87:111–7.Czigány T. Special manufacturing and characteristics of basalt fiber reinforced hybrid polypropylene composites: mechanical properties and acoustic emission study. Compos Sci Technol. 2006;66(16):3210–20.Marom G, Fischer S, Tuler FR, Wagner HD. Hybrid effects in composites: conditions for positive or negative effects versus rule-of-mixtures behaviour. J Mater Sci. 1978;13(7):1419–26.Torquato S. Random heterogeneous materials: microstructure and macroscopic properties. New York: Springer; 2002.Cherki A-B, Remy B, Khabbazi A, Jannot Y, Baillis D. Experimental thermal properties characterization of insulating cork–gypsum composite. Constr Build Mater. 2014;54:202–9.Bismarck A, Aranberri-Askargorta I, Springer J, Lampke T, Wielage B, Stamboulis A, et al. Surface characterization of flax, hemp and cellulose fibers; Surface properties and the water uptake behavior. Polym Compos. 2002;23(5):872–94.Motoc Luca D, Ferrandiz Bou S, Balart Gimeno R. Effects of fibre orientation and content on the mechanical, dynamic mechanical and thermal expansion properties of multi-layered glass/carbon fibre-reinforced polymer composites. J Compos Mater. 2014;49(10):1211–1221.CES EduPack. Granta Design; 2013.Monteiro SN, Calado V, Rodriguez RJS, Margem FM. Thermogravimetric behavior of natural fibers reinforced polymer composites—An overview. Mater Sci Eng, A. 2012;557:17–28

    Challenges to the surveillance of non-communicable diseases – a review of selected approaches

    Get PDF
    Background: The rising global burden of non-communicable diseases (NCDs) necessitates the institutionalization of surveillance systems to track trends and evaluate interventions. However, NCD surveillance capacities vary across high- and low- and middle-income countries. The objective of the review was to analyse existing literature with respect to structures of health facility-based NCD surveillance systems and the lessons low- and middle-income countries can learn in setting up and running these systems. Methods: A literature review was conducted using Pub Med, Web of Knowledge and WHOLIS databases to identify citations published in English language between 1993 and 2013. In total, 20 manuscripts met inclusion criteria: 12 studies were analysed in respect to the surveillance approach, eight supporting documents in respect to general and regional challenges in NCD surveillance. Results: Eleven of the 12 studies identified were conducted in high-income countries. Five studies had a single disease focus, three a multiple NCD focus and three covered communicable as well as non-communicable diseases. Nine studies were passive assisted sentinel surveillance systems, of which six focused on the primary care level and three had additional active surveillance components, i.e., population-based surveys. The supporting documents reveal that NCD surveillance is rather limited in most low- and middle-income countries despite the increasing disease burden and its socioeconomic impact. Major barriers include institutional surveillance capacities and hence data availability. Conclusions: The review suggests that given the complex system requirements, multiple surveillance approaches are necessary to collect comprehensive information for effective NCD surveillance. Sentinel augmented facility-based surveillance, preferably supported by population-based surveys, can provide improved evidence and help budget scarce resources. Electronic supplementary material: The online version of this article (doi:10.1186/s12889-015-2570-z) contains supplementary material, which is available to authorized users

    The Cysteine-Rich Protein Thimet Oligopeptidase as a Model of the Structural Requirements for S-glutathiolation and Oxidative Oligomerization

    Get PDF
    Thimet oligopeptidase (EP24.15) is a cysteine-rich metallopeptidase containing fifteen Cys residues and no intra-protein disulfide bonds. Previous work on this enzyme revealed that the oxidative oligomerization of EP24.15 is triggered by S-glutathiolation at physiological GSSG levels (10–50 µM) via a mechanism based on thiol-disulfide exchange. In the present work, our aim was to identify EP24.15 Cys residues that are prone to S-glutathiolation and to determine which structural features in the cysteinyl bulk are responsible for the formation of mixed disulfides through the reaction with GSSG and, in this particular case, the Cys residues within EP24.15 that favor either S-glutathiolation or inter-protein thiol-disulfide exchange. These studies were conducted by in silico structural analyses and simulations as well as site-specific mutation. S-glutathiolation was determined by mass spectrometric analyses and western blotting with anti-glutathione antibody. The results indicated that the stabilization of a thiolate sulfhydryl and the solvent accessibility of the cysteines are necessary for S-thiolation. The Solvent Access Surface analysis of the Cys residues prone to glutathione modification showed that the S-glutathiolated Cys residues are located inside pockets where the sulfur atom comes into contact with the solvent and that the positively charged amino acids are directed toward these Cys residues. The simulation of a covalent glutathione docking onto the same Cys residues allowed for perfect glutathione posing. A mutation of the Arg residue 263 that forms a saline bridge to the Cys residue 175 significantly decreased the overall S-glutathiolation and oligomerization of EP24.15. The present results show for the first time the structural requirements for protein S-glutathiolation by GSSG and are consistent with our previous hypothesis that EP24.15 oligomerization is dependent on the electron transfer from specific protonated Cys residues of one molecule to previously S-glutathionylated Cys residues of another one

    Prezygotic Barriers to Hybridization in Marine Broadcast Spawners: Reproductive Timing and Mating System Variation

    Get PDF
    Sympatric assemblages of congeners with incomplete reproductive barriers offer the opportunity to study the roles that ecological and non-ecological factors play in reproductive isolation. While interspecific asynchrony in gamete release and gametic incompatibility are known prezygotic barriers to hybridization, the role of mating system variation has been emphasized in plants. Reproductive isolation between the sibling brown algal species Fucus spiralis, Fucus guiryi (selfing hermaphrodite) and Fucus vesiculosus (dioecious) was studied because they form hybrids in parapatry in the rocky intertidal zone, maintain species integrity over a broad geographic range, and have contrasting mating systems. We compared reproductive synchrony (spawning overlap) between the three species at several temporal scales (yearly/seasonal, semilunar/tidal, and hourly during single tides). Interspecific patterns of egg release were coincident at seasonal (single peak in spring to early summer) to semilunar timescales. Synthesis of available data indicated that spawning is controlled by semidiurnal tidal and daily light-dark cues, and not directly by semilunar cycles. Importantly, interspecific shifts in timing detected at the hourly scale during single tides were consistent with a partial ecological prezygotic hybridization barrier. The species displayed patterns of gamete release consistent with a power law distribution, indicating a high degree of reproductive synchrony, while the hypothesis of weaker selective constraints for synchrony in selfing versus outcrossing species was supported by observed spawning in hermaphrodites over a broader range of tidal phase than in outcrossers. Synchronous gamete release is critical to the success of external fertilization, while high-energy intertidal environments may offer only limited windows of reproductive opportunity. Within these windows, however, subtle variations in reproductive timing have evolved with the potential to form ecological barriers to hybridization
    • …
    corecore