46 research outputs found

    Electron-Poor Butenolides:The Missing Link between Acrylates and Maleic Anhydride in Radical Polymerization

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    Butenolides are a class of 5-membered lactones that hold great potential as bio-based monomers to replace oil-derived acrylates, of which they are cyclic analogues. Despite this structural resemblance, the reactivity of the unsaturated ester moiety of electron-poor butenolides leans toward that of maleic anhydride, another essential monomer that does not homopolymerize but copolymerizes in a highly alternating fashion with polarized electron-rich comonomers. By studying the reactivity of 5-methoxy and 5-acyloxy butenolides through a combination of kinetics and density functional theory (DFT) experiments, we explain why electron-poor butenolides constitute a missing link between acrylates and maleic anhydride in radical polymerization.</p

    A sustainable polymer and coating system based on renewable raw materials

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    Paints and coatings are widely used in modern society and their current production is mainly dependent on the petrochemical industry. The establishment of processes using sustainable alternative monomers based on biorenewable resources, using exclusively biobased reagents and green synthetic transformations are highly warranted for a more sustainable future. Herein, we report on a sustainable polymer and coating system based on the monomer methoxybutenolide, a biobased acrylate alternative. Methoxybutenolide and the comonomer dodecyl vinyl ether are synthesized from biobased platform chemicals using the environmentally benign synthetic transformations photooxygenation and vinylation. For the photooxygenation, a biobased photosensitizer was developed showing high quantum yields. The monomers were copolymerized using biomass derived (photo)initiators to yield fully biobased polymers and coatings with properties comparable to acrylate based coatings

    Estudio transversal del crecimiento infantil y de adolescentes en Ecuador

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    Child growth is internationally recognized as an important indicator for monitoring health in populations. There exists a wide controversy regarding the use of international growth standards versus local references. This study seeks to construct reference growth curves for school-age Ecuadorian children and adolescents, and to compare them with World Health Organization (WHO) standards, in order to identify the differences and their public health implications. The study authors enrolled 2891 children (1644 girls and 1247 boys) aged 5 to 18 years, from a variety of climatic zones and ethnic groups. LMS method was used to construct Ecuadorian curves for height, weight and Body Mass Index. Comparisons of Ecuadorian and WHO curves were graphically illustrated. U.S children were taller than Ecuadorian children across all age ranges, with larger differences between the two populations in children over 13 years. Consequently, estimates of low height and extremely low height, as well as overweight, obese and undernourished, were significantly different between WHO standards and the Ecuadorian references. Population-specific growth curves may be more adequate for growth monitoring of Ecuadorian children than WHO growth curves. We advocate for the construction of an Ecuadorian growth reference for clinical use based on national population, from conception to maturity, as an accurate instrument for monitoring growth.El crecimiento infantil es reconocido internacionalmente como un indicador importante para monitorear la salud en las poblaciones. Existe una gran controversia con respecto al uso de estĂĄndares de crecimiento internacional versus referencias locales. Este estudio busca construir referencias de crecimiento para niños y adolescentes ecuatorianos, y compararlas con los estĂĄndares de la OrganizaciĂłn Mundial de la Salud (OMS), para identificar las diferencias y sus implicaciones para la salud pĂșblica. Se incluyĂł 2891 niños (1644 niñas y 1247 niños) de 5 a 18 años de una variedad de zonas climĂĄticas y grupos Ă©tnicos. El mĂ©todo LMS se utilizĂł para construir las curvas ecuatorianas de altura, peso e Ă­ndice de masa corporal. Las comparaciones de curvas ecuatorianas y de la OMS se ilustraron grĂĄficamente. Los niños de EE. UU., fueron mĂĄs altos que los niños ecuatorianos en todos los rangos de edad, con mayores diferencias entre las dos poblaciones en niños mayores de 13 años. En consecuencia, las estimaciones de baja altura y altura extremadamente baja, asĂ­ como sobrepeso, obesidad y desnutriciĂłn, fueron significativamente diferentes entre los estĂĄndares de la OMS y las referencias ecuatorianas. Las curvas de crecimiento especĂ­ficas de la poblaciĂłn pueden ser un parĂĄmetro de monitoreo del crecimiento para niños ecuatorianos mĂĄs adecuado que las curvas de crecimiento de la OMS. Abogamos por la construcciĂłn de una referencia de crecimiento ecuatoriana para uso clĂ­nico basada en la poblaciĂłn nacional, desde la concepciĂłn hasta la madurez, como un instrumento preciso para monitorear el crecimiento.AsociaciĂłn de AntropologĂ­a BiolĂłgica de la RepĂșblica Argentin

    Estudio transversal del crecimiento infantil y de adolescentes en Ecuador

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    Child growth is internationally recognized as an important indicator for monitoring health in populations. There exists a wide controversy regarding the use of international growth standards versus local references. This study seeks to construct reference growth curves for school-age Ecuadorian children and adolescents, and to compare them with World Health Organization (WHO) standards, in order to identify the differences and their public health implications. The study authors enrolled 2891 children (1644 girls and 1247 boys) aged 5 to 18 years, from a variety of climatic zones and ethnic groups. LMS method was used to construct Ecuadorian curves for height, weight and Body Mass Index. Comparisons of Ecuadorian and WHO curves were graphically illustrated. U.S children were taller than Ecuadorian children across all age ranges, with larger differences between the two populations in children over 13 years. Consequently, estimates of low height and extremely low height, as well as overweight, obese and undernourished, were significantly different between WHO standards and the Ecuadorian references. Population-specific growth curves may be more adequate for growth monitoring of Ecuadorian children than WHO growth curves. We advocate for the construction of an Ecuadorian growth reference for clinical use based on national population, from conception to maturity, as an accurate instrument for monitoring growth.El crecimiento infantil es reconocido internacionalmente como un indicador importante para monitorear la salud en las poblaciones. Existe una gran controversia con respecto al uso de estĂĄndares de crecimiento internacional versus referencias locales. Este estudio busca construir referencias de crecimiento para niños y adolescentes ecuatorianos, y compararlas con los estĂĄndares de la OrganizaciĂłn Mundial de la Salud (OMS), para identificar las diferencias y sus implicaciones para la salud pĂșblica. Se incluyĂł 2891 niños (1644 niñas y 1247 niños) de 5 a 18 años de una variedad de zonas climĂĄticas y grupos Ă©tnicos. El mĂ©todo LMS se utilizĂł para construir las curvas ecuatorianas de altura, peso e Ă­ndice de masa corporal. Las comparaciones de curvas ecuatorianas y de la OMS se ilustraron grĂĄficamente. Los niños de EE. UU., fueron mĂĄs altos que los niños ecuatorianos en todos los rangos de edad, con mayores diferencias entre las dos poblaciones en niños mayores de 13 años. En consecuencia, las estimaciones de baja altura y altura extremadamente baja, asĂ­ como sobrepeso, obesidad y desnutriciĂłn, fueron significativamente diferentes entre los estĂĄndares de la OMS y las referencias ecuatorianas. Las curvas de crecimiento especĂ­ficas de la poblaciĂłn pueden ser un parĂĄmetro de monitoreo del crecimiento para niños ecuatorianos mĂĄs adecuado que las curvas de crecimiento de la OMS. Abogamos por la construcciĂłn de una referencia de crecimiento ecuatoriana para uso clĂ­nico basada en la poblaciĂłn nacional, desde la concepciĂłn hasta la madurez, como un instrumento preciso para monitorear el crecimiento.AsociaciĂłn de AntropologĂ­a BiolĂłgica de la RepĂșblica Argentin

    Estudio transversal del crecimiento infantil y de adolescentes en Ecuador

    Get PDF
    Child growth is internationally recognized as an important indicator for monitoring health in populations. There exists a wide controversy regarding the use of international growth standards versus local references. This study seeks to construct reference growth curves for school-age Ecuadorian children and adolescents, and to compare them with World Health Organization (WHO) standards, in order to identify the differences and their public health implications. The study authors enrolled 2891 children (1644 girls and 1247 boys) aged 5 to 18 years, from a variety of climatic zones and ethnic groups. LMS method was used to construct Ecuadorian curves for height, weight and Body Mass Index. Comparisons of Ecuadorian and WHO curves were graphically illustrated. U.S children were taller than Ecuadorian children across all age ranges, with larger differences between the two populations in children over 13 years. Consequently, estimates of low height and extremely low height, as well as overweight, obese and undernourished, were significantly different between WHO standards and the Ecuadorian references. Population-specific growth curves may be more adequate for growth monitoring of Ecuadorian children than WHO growth curves. We advocate for the construction of an Ecuadorian growth reference for clinical use based on national population, from conception to maturity, as an accurate instrument for monitoring growth.El crecimiento infantil es reconocido internacionalmente como un indicador importante para monitorear la salud en las poblaciones. Existe una gran controversia con respecto al uso de estĂĄndares de crecimiento internacional versus referencias locales. Este estudio busca construir referencias de crecimiento para niños y adolescentes ecuatorianos, y compararlas con los estĂĄndares de la OrganizaciĂłn Mundial de la Salud (OMS), para identificar las diferencias y sus implicaciones para la salud pĂșblica. Se incluyĂł 2891 niños (1644 niñas y 1247 niños) de 5 a 18 años de una variedad de zonas climĂĄticas y grupos Ă©tnicos. El mĂ©todo LMS se utilizĂł para construir las curvas ecuatorianas de altura, peso e Ă­ndice de masa corporal. Las comparaciones de curvas ecuatorianas y de la OMS se ilustraron grĂĄficamente. Los niños de EE. UU., fueron mĂĄs altos que los niños ecuatorianos en todos los rangos de edad, con mayores diferencias entre las dos poblaciones en niños mayores de 13 años. En consecuencia, las estimaciones de baja altura y altura extremadamente baja, asĂ­ como sobrepeso, obesidad y desnutriciĂłn, fueron significativamente diferentes entre los estĂĄndares de la OMS y las referencias ecuatorianas. Las curvas de crecimiento especĂ­ficas de la poblaciĂłn pueden ser un parĂĄmetro de monitoreo del crecimiento para niños ecuatorianos mĂĄs adecuado que las curvas de crecimiento de la OMS. Abogamos por la construcciĂłn de una referencia de crecimiento ecuatoriana para uso clĂ­nico basada en la poblaciĂłn nacional, desde la concepciĂłn hasta la madurez, como un instrumento preciso para monitorear el crecimiento.AsociaciĂłn de AntropologĂ­a BiolĂłgica de la RepĂșblica Argentin

    Structural Basis of Outstanding Multivalent Effects in Jack Bean α-Mannosidase Inhibition

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    Multivalent design of glycosidase inhibitors is a promising strategy for the treatment of diseases involving enzymatic hydrolysis of glycosidic bonds in carbohydrates. An essential prerequisite for successful applications is the atomic‐level understanding of how outstanding binding enhancement occurs with multivalent inhibitors. Herein we report the first high‐resolution crystal structures of the Jack bean α‐mannosidase (JBα‐man) in apo and inhibited states. The three‐dimensional structure of JBα‐man in complex with the multimeric cyclopeptoid‐based inhibitor displaying the largest binding enhancements reported so far provides decisive insight into the molecular mechanisms underlying multivalent effects in glycosidase inhibition.Instituto de FĂ­sica de LĂ­quidos y Sistemas BiolĂłgico

    Dynamic phase diagram of the REM

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    By studying the two-time overlap correlation function, we give a comprehensive analysis of the phase diagram of the Random Hopping Dynamics of the Random Energy Model (REM) on time-scales that are exponential in the volume. These results are derived from the convergence properties of the clock process associated to the dynamics and fine properties of the simple random walk in the nn-dimensional discrete cube.Comment: This paper is in large part based on the unpublished work arXiv:1008.3849. In particular, the analysis of the overlap correlation function is new as well as the study of the high temperature and short time-scale transition line between aging and stationarit

    Induction of Selective Blood-Tumor Barrier Permeability and Macromolecular Transport by a Biostable Kinin B1 Receptor Agonist in a Glioma Rat Model

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    Treatment of malignant glioma with chemotherapy is limited mostly because of delivery impediment related to the blood-brain tumor barrier (BTB). B1 receptors (B1R), inducible prototypical G-protein coupled receptors (GPCR) can regulate permeability of vessels including possibly that of brain tumors. Here, we determine the extent of BTB permeability induced by the natural and synthetic peptide B1R agonists, LysdesArg9BK (LDBK) and SarLys[dPhe8]desArg9BK (NG29), in syngeneic F98 glioma-implanted Fischer rats. Ten days after tumor inoculation, we detected the presence of B1R on tumor cells and associated vasculature. NG29 infusion increased brain distribution volume and uptake profiles of paramagnetic probes (Magnevist and Gadomer) at tumoral sites (T1-weighted imaging). These effects were blocked by B1R antagonist and non-selective cyclooxygenase inhibitors, but not by B2R antagonist and non-selective nitric oxide synthase inhibitors. Consistent with MRI data, systemic co-administration of NG29 improved brain tumor delivery of Carboplatin chemotherapy (ICP-Mass spectrometry). We also detected elevated B1R expression in clinical samples of high-grade glioma. Our results documented a novel GPCR-signaling mechanism for promoting transient BTB disruption, involving activation of B1R and ensuing production of COX metabolites. They also underlined the potential value of synthetic biostable B1R agonists as selective BTB modulators for local delivery of different sized-therapeutics at (peri)tumoral sites

    The Bank of Standardized Stimuli (BOSS), a New Set of 480 Normative Photos of Objects to Be Used as Visual Stimuli in Cognitive Research

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    There are currently stimuli with published norms available to study several psychological aspects of language and visual cognitions. Norms represent valuable information that can be used as experimental variables or systematically controlled to limit their potential influence on another experimental manipulation. The present work proposes 480 photo stimuli that have been normalized for name, category, familiarity, visual complexity, object agreement, viewpoint agreement, and manipulability. Stimuli are also available in grayscale, blurred, scrambled, and line-drawn version. This set of objects, the Bank Of Standardized Stimuli (BOSS), was created specifically to meet the needs of scientists in cognition, vision and psycholinguistics who work with photo stimuli

    Comparison of user groups' perspectives of barriers and facilitators to implementing electronic health records: a systematic review

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    <p>Abstract</p> <p>Background</p> <p>Electronic health record (EHR) implementation is currently underway in Canada, as in many other countries. These ambitious projects involve many stakeholders with unique perceptions of the implementation process. EHR users have an important role to play as they must integrate the EHR system into their work environments and use it in their everyday activities. Users hold valuable, first-hand knowledge of what can limit or contribute to the success of EHR implementation projects. A comprehensive synthesis of EHR users' perceptions is key to successful future implementation. This systematic literature review was aimed to synthesize current knowledge of the barriers and facilitators influencing shared EHR implementation among its various users.</p> <p>Methods</p> <p>Covering a period from 1999 to 2009, a literature search was conducted on nine electronic databases. Studies were included if they reported on users' perceived barriers and facilitators to shared EHR implementation, in healthcare settings comparable to Canada. Studies in all languages with an empirical study design were included. Quality and relevance of the studies were assessed. Four EHR user groups were targeted: physicians, other health care professionals, managers, and patients/public. Content analysis was performed independently by two authors using a validated extraction grid with pre-established categorization of barriers and facilitators for each group of EHR users.</p> <p>Results</p> <p>Of a total of 5,695 potentially relevant publications identified, 117 full text publications were obtained after screening titles and abstracts. After review of the full articles, 60 publications, corresponding to 52 studies, met the inclusion criteria. The most frequent adoption factors common to all user groups were design and technical concerns, ease of use, interoperability, privacy and security, costs, productivity, familiarity and ability with EHR, motivation to use EHR, patient and health professional interaction, and lack of time and workload. Each user group also identified factors specific to their professional and individual priorities.</p> <p>Conclusions</p> <p>This systematic review presents innovative research on the barriers and facilitators to EHR implementation. While important similarities between user groups are highlighted, differences between them demonstrate that each user group also has a unique perspective of the implementation process that should be taken into account.</p
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