388 research outputs found

    Influence of the oxidizing agent in the synthesis of graphite oxide

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    The oxidation capacity of several procedures described in the literature which use different oxidizing agents has been exhaustively studied in order to describe the best route for oxidation of this material. The oxidation capacities of different types of materials were evaluated in the synthesis of graphite oxide in an effort to obtain a product with similar characteristics to those provided by commonly employed methods. The results obtained show that graphite oxide structures are greatly influenced by the nature of the oxidizing agent used. It was concluded that it is possible not only to establish the number of oxygenated groups attached to the structure but also, and depending on the oxidizing agent used, to know the stability of graphite oxide. The different characteristics of each graphite oxide obtained could facilitate their use in multiple applications.La capacidad de oxidación de varios procedimientos descritos en la literatura que utilizan diferentes agentes oxidantes ha sido exhaustivamente estudiada con el fin de describir la mejor ruta de oxidación de este material. Se evaluaron las capacidades de oxidación de diferentes tipos de materiales en la síntesis de óxido de grafito en un esfuerzo por obtener un producto con características similares a las proporcionadas por los métodos comúnmente empleados. Los resultados obtenidos muestran que las estructuras del óxido de grafito están muy influenciadas por la naturaleza del agente oxidante utilizado. Se concluyó que es posible no solo establecer el número de grupos oxigenados adheridos a la estructura sino también, y dependiendo del agente oxidante utilizado, conocer la estabilidad del óxido de grafito

    Effects of oxidizing procedures on carbon nanofibers surface and dispersability in an epoxy resin

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    Different oxygen functionalities were introduced in fishbone-type carbon nanofibers (CNFs) using three different oxidation procedures. The differences between these procedures are mainly based in the oxidizing agent used and the acid medium in which the process was carried out. Potassium permanganate-, ferrate- and chromate-based approaches were employed in conjunction with exfoliation and subsequent reduction with hydrazine. A complete evaluation of the effects produced by the different oxidative treatments on the resulting materials was carried out. The obtained materials were characterized by Scanning Electron Microscopy (SEM), EDX, RAMAN, Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), N2 adsorption/desorption measurements, particle size and thermogravimetric analysis. The results suggest that only those procedures in which H2SO4 was used as acid medium (i.e., potassium permanganate and ferrate processes) were fit to achieve intercalation of suitable species (SO42− ions) that weaken the van der Waals forces. The weakening of these forces facilitates the attack of the carbon skeleton by the strong oxidants MnO4− or FeO42–and, as a consequence, the fragmentation of the material occurs. Dispersibility of carbon materials are affected by functional groups and oxidation degree. Turbiscan stability index provide a useful tool in order to study the stability of carbon material into different solvents with different dipole moments: water, epoxy resin and decane.Se introdujeron diferentes funcionalidades de oxígeno en nanofibras de carbono tipo espina de pescado (CNF) utilizando tres procedimientos de oxidación diferentes. Las diferencias entre estos procedimientos se basan principalmente en el agente oxidante utilizado y el medio ácido en el que se llevó a cabo el proceso. Se emplearon enfoques basados ​​en permanganato, ferrato y cromato de potasio junto con la exfoliación y la posterior reducción con hidracina. Se realizó una evaluación completa de los efectos producidos por los diferentes tratamientos oxidativos sobre los materiales resultantes. Los materiales obtenidos se caracterizaron por microscopía electrónica de barrido (SEM), EDX , RAMAN, infrarrojo transformado de Fourier (FTIR), difracción de rayos X (XRD), medidas de adsorción/desorción de N 2 , tamaño de partícula yanálisis termogravimétrico . Los resultados sugieren que solo aquellos procedimientos en los que se usó H 2 SO 4 como medio ácido (es decir, procesos de permanganato y ferrato de potasio ) fueron aptos para lograr la intercalación de especies adecuadas (iones SO 4 2− ) que debilitan las fuerzas de van der Waals. El debilitamiento de estas fuerzas facilita el ataque de la estructura carbonada por los oxidantes fuertes MnO 4 − o FeO 4 2–y, como consecuencia, se produce la fragmentación del material. La dispersabilidad de los materiales de carbono se ve afectada por los grupos funcionales y el grado de oxidación. El índice de estabilidad Turbiscan proporciona una herramienta útil para estudiar la estabilidad del material de carbono en diferentes solventes con diferentes momentos dipolares : agua, resina epoxi y decano

    Role of inert gas in the Cvd-graphene synthesis over polycrystalline nickel foils

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    The role of the inert gas during CVD-graphene growth over polycrystalline nickel foils is reported. Nitrogen, hydrogen and methane were used as inert, reduction and carbonaceous gases, respectively. Graphene samples were characterized by using Optical Microscopy, Raman Spectroscopy and SEM equipped with EDX. Four different colors were distinguished over the optical microscope images. These colors were analyzed by Raman Spectroscopy and correlated to each type of graphene deposited over the foil (monolayer, bilayer, few-layers and multilayer). An Excel-VBA application was developed, which was used for computing the percentage of each type of graphene, resulting in an estimation of the graphene quality value. It was verified that the incorporation of the inert gas in the reaction step during CVD-graphene synthesis greatly influenced the quality of the obtained graphene. Different temperatures and percentages of nitrogen were studied in order to define the optimal reaction conditions. A factorial design study was performed to find the best experimental conditions leading to the highest quality graphene value, which resulted to be the following ones: 947 °C and 13 vol % of nitrogen in the feed stream, 1 min of reaction time, a relation between CH4 and H2 of 0.07 v/v, and a total flow of gases of 80 Nml/min.Se informa sobre el papel del gas inerte durante el crecimiento de CVD-grafeno sobre láminas de níquel policristalino . Se utilizaron nitrógeno, hidrógeno y metano como gases inertes, de reducción y carbonosos, respectivamente. Las muestras de grafeno se caracterizaron utilizando Microscopía Óptica, Espectroscopía Raman y SEM equipado con EDX .. Se distinguieron cuatro colores diferentes sobre las imágenes del microscopio óptico. Estos colores se analizaron mediante espectroscopia Raman y se correlacionaron con cada tipo de grafeno depositado sobre la lámina (monocapa, bicapa, pocas capas y multicapa). Se desarrolló una aplicación Excel-VBA, la cual se utilizó para calcular el porcentaje de cada tipo de grafeno, dando como resultado una estimación del valor de la calidad del grafeno. Se comprobó que la incorporación del gas inerte en el paso de reacción durante la síntesis de CVD-grafeno influyó mucho en la calidad del grafeno obtenido. Se estudiaron diferentes temperaturas y porcentajes de nitrógeno para definir las condiciones óptimas de reacción. Se realizó un estudio de diseño factorial para encontrar las mejores condiciones experimentales que conduzcan al valor de grafeno de mayor calidad, las cuales resultaron ser las siguientes:4 y H 2 de 0,07 v/v, y un caudal total de gases de 80 Nml/min

    The effect of orthodontic forces on calcitonin gene-related peptide (CGRP) expression in the human periodontal ligament and its relationship with the human dental pulp

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    The purpose of this study was to quantify the effect of moderate and severe orthodontic forces on Calcitonin gene-related peptide (CGRP) expression in the healthy human periodontal ligament (PDL) and its possible relationship with the human dental pulp

    Clinical information modeling processes for semantic interoperability of electronic health records: systematic review and inductive analysis

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    This is a pre-copyedited, author-produced PDF of an article accepted for publication in Journal of the American Medical Informatics Association following peer review. The version of record is available online at: http://dx.doi.org/10.1093/jamia/ocv008[EN] [Objective] This systematic review aims to identify and compare the existing processes and methodologies that have been published in the literature for defining clinical information models (CIMs) that support the semantic interoperability of electronic health record (EHR) systems. [Material and Methods] Following the preferred reporting items for systematic reviews and meta-analyses systematic review methodology, the authors reviewed published papers between 2000 and 2013 that covered that semantic interoperability of EHRs, found by searching the PubMed, IEEE Xplore, and ScienceDirect databases. Additionally, after selection of a final group of articles, an inductive content analysis was done to summarize the steps and methodologies followed in order to build CIMs described in those articles. [Results] Three hundred and seventy-eight articles were screened and thirty six were selected for full review. The articles selected for full review were analyzed to extract relevant information for the analysis and characterized according to the steps the authors had followed for clinical information modeling. [Discussion] Most of the reviewed papers lack a detailed description of the modeling methodologies used to create CIMs. A representative example is the lack of description related to the definition of terminology bindings and the publication of the generated models. However, this systematic review confirms that most clinical information modeling activities follow very similar steps for the definition of CIMs. Having a robust and shared methodology could improve their correctness, reliability, and quality. [Conclusion] Independently of implementation technologies and standards, it is possible to find common patterns in methods for developing CIMs, suggesting the viability of defining a unified good practice methodology to be used by any clinical information modeler.This research has been partially funded by the Instituto de Salud Carlos III (Platform for Innovation in Medical Technologies and Health), grant PT13/0006/0036 and the Spanish Ministry of Economy and Competitiveness, grants TIN2010-21388-C02-01 and PTQ-12-05620.Moreno-Conde, A.; Moner Cano, D.; Da Cruz, WD.; Santos, MR.; Maldonado Segura, JA.; Robles Viejo, M.; Kalra, D. (2015). Clinical information modeling processes for semantic interoperability of electronic health records: systematic review and inductive analysis. Journal of the American Medical Informatics Association. 22(4):925-934. https://doi.org/10.1093/jamia/ocv008S925934224Goossen W Goossen-Baremans A van der Zel M . Detailed clinical models: a review. Healthc Inform Res. 2010;16:201.Beeler, G. W. (1998). HL7 Version 3—An object-oriented methodology for collaborative standards development1Presented at the International Medical Informatics Association Working Group 16 Conference on Standardisation in Medical Informatics—Towards International Consensus and Cooperation, Bermuda, 12 September, 1997.1. International Journal of Medical Informatics, 48(1-3), 151-161. doi:10.1016/s1386-5056(97)00121-4Dolin, R. H., Alschuler, L., Boyer, S., Beebe, C., Behlen, F. M., Biron, P. V., & Shabo (Shvo), A. (2006). HL7 Clinical Document Architecture, Release 2. 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Editorial principles for the development of standards for the structure and content of health records. 2012. https://www.rcplondon.ac.uk/sites/default/files/documents/editorial-principles-for-the-development-of-record-standards.pdf . Accessed July 18, 2015.Yuksel, M., & Dogac, A. (2011). Interoperability of Medical Device Information and the Clinical Applications: An HL7 RMIM based on the ISO/IEEE 11073 DIM. IEEE Transactions on Information Technology in Biomedicine, 15(4), 557-566. doi:10.1109/titb.2011.2151868Nagy M Hanzlicek P Precková P . Semantic interoperability in Czech healthcare environment supported by HL7 version 3. Methods Inf Med. 2010;49:186.LOPEZ, D., & BLOBEL, B. (2009). A development framework for semantically interoperable health information systems. International Journal of Medical Informatics, 78(2), 83-103. doi:10.1016/j.ijmedinf.2008.05.009Lopez DM Blobel B . Enhanced semantic interoperability by profiling health informatics standards. Methods Inf Med. 2009;48:170–177.Lopez DM Blobel B . Enhanced semantic interpretability by healthcare standards profiling. Stud Health Technol Inform. 2008;136:735.Knaup, P., Garde, S., & Haux, R. (2007). Systematic planning of patient records for cooperative care and multicenter research. International Journal of Medical Informatics, 76(2-3), 109-117. doi:10.1016/j.ijmedinf.2006.08.002Goossen, W. T. F., Ozbolt, J. G., Coenen, A., Park, H.-A., Mead, C., Ehnfors, M., & Marin, H. F. (2004). Development of a Provisional Domain Model for the Nursing Process for Use within the Health Level 7 Reference Information Model. Journal of the American Medical Informatics Association, 11(3), 186-194. doi:10.1197/jamia.m1085Anderson, H. V., Weintraub, W. S., Radford, M. J., Kremers, M. S., Roe, M. T., Shaw, R. E., … Tcheng, J. E. (2013). Standardized Cardiovascular Data for Clinical Research, Registries, and Patient Care. Journal of the American College of Cardiology, 61(18), 1835-1846. doi:10.1016/j.jacc.2012.12.047Jian, W.-S., Hsu, C.-Y., Hao, T.-H., Wen, H.-C., Hsu, M.-H., Lee, Y.-L., … Chang, P. (2007). Building a portable data and information interoperability infrastructure—framework for a standard Taiwan Electronic Medical Record Template. Computer Methods and Programs in Biomedicine, 88(2), 102-111. doi:10.1016/j.cmpb.2007.07.014Spigolon, D. N., & Moro, C. M. C. (2012). Arquétipos do conjunto de dados essenciais de enfermagem para atendimento de portadoras de endometriose. Revista Gaúcha de Enfermagem, 33(4), 22-32. doi:10.1590/s1983-14472012000400003Späth, M. B., & Grimson, J. (2011). Applying the archetype approach to the database of a biobank information management system. International Journal of Medical Informatics, 80(3), 205-226. doi:10.1016/j.ijmedinf.2010.11.002Smith, K., & Kalra, D. (2008). Electronic health records in complementary and alternative medicine. International Journal of Medical Informatics, 77(9), 576-588. doi:10.1016/j.ijmedinf.2007.11.005Bax, M. P., Kalra, D., & Santos, M. R. (2012). Dealing with the Archetypes Development Process for a Regional EHR System. Applied Clinical Informatics, 03(03), 258-275. doi:10.4338/aci-2011-12-ra-0074Moner D Moreno A Maldonado JA . Using archetypes for defining CDA templates. Stud Health Technol Inform. 2012;180:53–57.Moner D Maldonado JA Boscá D . CEN EN13606 normalisation framework implementation experiences. In: Seamless Care, Safe Care: The Challenges of Interoperability and Patient Safety in Health Care: Proceedings of the EFMI Special Topic Conference, June 2–4, 2010; Reykjavik, Iceland. IOS Press; 2010: 136.Marcos, M., Maldonado, J. A., Martínez-Salvador, B., Boscá, D., & Robles, M. (2013). Interoperability of clinical decision-support systems and electronic health records using archetypes: A case study in clinical trial eligibility. 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The EHR-ARCHE project: Satisfying clinical information needs in a Shared Electronic Health Record System based on IHE XDS and Archetypes. International Journal of Medical Informatics, 82(12), 1195-1207. doi:10.1016/j.ijmedinf.2013.08.002Dias, R. D., Cook, T. W., & Freire, S. M. (2011). Modeling healthcare authorization and claim submissions using the openEHR dual-model approach. BMC Medical Informatics and Decision Making, 11(1). doi:10.1186/1472-6947-11-60Buck, J., Garde, S., Kohl, C. D., & Knaup-Gregori, P. (2009). Towards a comprehensive electronic patient record to support an innovative individual care concept for premature infants using the openEHR approach. International Journal of Medical Informatics, 78(8), 521-531. doi:10.1016/j.ijmedinf.2009.03.001Puentes, J., Roux, M., Montagner, J., & Lecornu, L. (2012). Development framework for a patient-centered record. 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Telemedicine and e-Health, 19(8), 632-642. doi:10.1089/tmj.2012.0189Jing, X., Kay, S., Marley, T., Hardiker, N. R., & Cimino, J. J. (2012). Incorporating personalized gene sequence variants, molecular genetics knowledge, and health knowledge into an EHR prototype based on the Continuity of Care Record standard. Journal of Biomedical Informatics, 45(1), 82-92. doi:10.1016/j.jbi.2011.09.001Hsu, W., Taira, R. K., El-Saden, S., Kangarloo, H., & Bui, A. A. T. (2012). Context-Based Electronic Health Record: Toward Patient Specific Healthcare. IEEE Transactions on Information Technology in Biomedicine, 16(2), 228-234. doi:10.1109/titb.2012.2186149Hoy D Hardiker NR McNicoll IT . Collaborative development of clinical templates as a national resource. Int J Med Inf. 2009;78:S3–S8.Buyl, R., & Nyssen, M. (2009). Structured electronic physiotherapy records. International Journal of Medical Informatics, 78(7), 473-481. doi:10.1016/j.ijmedinf.2009.02.007D’Amore JD Mandel JC Kreda DA . Are Meaningful Use Stage 2 certified EHRs ready for interoperability? Findings from the SMART C-CDA Collaborative. J Am Med Inform Assoc. 2014. Advance access published; doi:10.1136/amiajnl-2014-002883.Kalra D Tapuria A Austin T . Quality requirements for EHR archetypes. In: MIE; 2012: 48–52.Garde S Hovenga EJ Gränz J . Managing archetypes for sustainable and semantically interoperable electronic health records. Electron J Health Inform. 2007;2:e9.Madsen M Leslie H Hovenga EJS . Sustainable clinical knowledge management: an archetype development life cycle. Stud Health Technol Inform. 2010;151:115–132.Kohl CD Garde S Knaup P . Facilitating the openEHR approach-organizational structures for defining high-quality archetypes. Stud Health Technol Inform. 2008;136:437.Stroetmann VN Kalra D Lewalle P . Semantic interoperability for better health and safer healthcare. European Commission, Directorate-General Information Society and Media; 2009. http://dx.doi.org/10.2759/38514

    Different strategies to simultaneously N-doping and reduce graphene oxide for electrocatalytic applications

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    Two different approaches to simultaneously introduce nitrogen atoms within the graphene framework and, reduce graphene oxide nanoplatelets (GO), have been explored in order to improve the electrocatalytic activity of the resulting materials. Thus, a facile hydrothermal method using 2-chloroethylamine under conditions at 180 °C and, another one, based in the formation of polypyrrole (PPy) on graphene oxide nanoplatelets by in situ polymerization of pyrrole monomer in the presence of GO, were compared through a deep characterization of the final materials by SEM, RAMAN, FTIR, XPS, Zeta potential, XRD and TGA analysis. Physico-chemical properties of the graphene-based materials were subsequently related with their electron transfer efficiency and electrocatalytic activity. The as prepared rGO prepared by the PPy method showed an N content quite superior (~6–8%) than the rGO prepared by the hydrothermal one (~1%) being an important part of their nitrogen state pyridinic type. The electrocatalytic results showed that GO exhibited higher specific capacitance than rGO materials due to its intrinsic higher porosity. However, the presence of N species seems to have a positive effect on the ORR activity, although the N incorporation through the PPy-rGO synthesis method seems to be the preferred one according for the complete ORR pathway.Se han explorado dos enfoques diferentes para introducir simultáneamente átomos de nitrógeno dentro del marco de grafeno y reducir las nanoplaquetas de óxido de grafeno ( GO) con el fin de mejorar la actividad electrocatalítica de los materiales resultantes. Así, se comparó un método hidrotermal fácil usando 2-cloroetilamina en condiciones a 180 °C y otro, basado en la formación de polipirrol (PPy) sobre nanoplaquetas de óxido de grafeno por polimerización in situ del monómero pirrol en presencia de GO. una caracterización profunda de los materiales finales por SEM, RAMAN, FTIR, XPS , potencial Zeta , XRD yanálisis TGA . Las propiedades fisicoquímicas de los materiales a base de grafeno se relacionaron posteriormente con su eficiencia de transferencia de electrones y su actividad electrocatalítica. El rGO preparado por el método PPy mostró un contenido de N bastante superior (~6–8%) que el rGO preparado por el hidrotermal (~1%) siendo una parte importante de su estado nitrogenado de tipo piridínico. Los resultados electrocatalíticos mostraron que GO exhibió una capacitancia específica más alta que los materiales rGO debido a su mayor porosidad intrínseca. Sin embargo, la presencia de especies de N parece tener un efecto positivo sobre la actividad de ORR, aunque la incorporación de N a través del método de síntesis de PPy-rGO parece ser el preferido según la vía completa de ORR

    Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

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    Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI

    Protozoan Parasites and Type I IFNs

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    International audienceFor many years, the role of interferon (IFN)-I has been characterized primarily in the context of viral infections. However, regulatory functions mediated by IFN-I have also been described against bacterial infections and in tumor immunology. Only recently, the interest in understanding the immune functions mediated by IFN-I has dramatically increased in the field of protozoan infections. In this review, we discuss the discrete role of IFN-I in the immune response against major protozoan infections: Plasmodium, Leishmania, Trypanosoma, and Toxoplasma

    Differential Expression of Iron Acquisition Genes by Brucella melitensis and Brucella canis during Macrophage Infection

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    Brucella spp. cause chronic zoonotic disease often affecting individuals and animals in impoverished economic or public health conditions; however, these bacteria do not have obvious virulence factors. Restriction of iron availability to pathogens is an effective strategy of host defense. For brucellae, virulence depends on the ability to survive and replicate within the host cell where iron is an essential nutrient for the growth and survival of both mammalian and bacterial cells. Iron is a particularly scarce nutrient for bacteria with an intracellular lifestyle. Brucella melitensis and Brucella canis share ∼99% of their genomes but differ in intracellular lifestyles. To identify differences, gene transcription of these two pathogens was examined during infection of murine macrophages and compared to broth grown bacteria. Transcriptome analysis of B. melitensis and B. canis revealed differences of genes involved in iron transport. Gene transcription of the TonB, enterobactin, and ferric anguibactin transport systems was increased in B. canis but not B. melitensis during infection of macrophages. The data suggest differences in iron requirements that may contribute to differences observed in the lifestyles of these closely related pathogens. The initial importance of iron for B. canis but not for B. melitensis helps elucidate differing intracellular survival strategies for two closely related bacteria and provides insight for controlling these pathogens
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