41 research outputs found

    Testing PtCu nanoparticles supported on highly ordered mesoporous carbons CMK3 and CMK8 as catalysts for low-temperature fuel cells

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    Pt(Cu) nanoparticles supported on CMK3 and CMK8 ordered mesoporous carbons (OMCs) have been synthesized by electroless deposition of Cu followed by galvanic exchange with Pt. The structural characterization by high-resolution transmission electron microscopy and X-ray diffraction showed the formation of Pt(Cu) nanoparticles of 4-5 nm, in which PtCu alloys with contracted fcc Pt lattice and 70-80 at.% Pt was identified. The X-ray photoelectron spectroscopy analyses indicated that the Pt(Cu) nanoparticles were mainly composed of a PtCu alloy core covered by a Ptrich shell, in agreement with the steady cyclic voltammograms, which did not show any Cu oxidation peaks. Electroactive surface areas up to about 70 m2 gPt−1 were obtained. The onset potentials for CO oxidation and the oxygen reduction reaction were more negative and positive, respectively, as compared to Pt/C, thus indicating higher activity of these Pt(Cu) catalysts with respect to the latter. Based on the corresponding binding energies, these better activities were attributed to the favorable geometric and ligand effects of Cu on Pt, which were able to reduce the adsorption energy of the intermediates on Pt. Pt(Cu)/CMK3 showed competitive mass and specific activities, as well as better stability than Pt/C

    Nanostructuring determines poisoning: Tailoring CO adsorption on PtCu bimetallic nanoparticles.

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    Here we show, combining CO stripping voltammograms on different PtCu nanoparticle (NP) low-temperature fuel cell electrocatalysts and density functional calculations, that surface chemical ordering and the presence of certain defects explain the CO tolerance vs. poisoning of such systems. The CO withdrawal for these duelling CO-slingers depends on whether they are well-shaped core@shell Cu@Pt NPs, more CO-tolerant, or having Cu-surrounded surface Pt atoms or adatoms/vacancies surface defects, less CO-tolerant. The latter sites are critical on nm-sized PtCu NPs, displaying stronger CO adsorption compared to pure Pt NPs. Avoiding such sites is key when designing less expensive and CO-poisoned Cu@Pt NP-based electrocatalysts

    Synthesis and evaluation of PtNi electrocatalysts for CO and methanol oxidation in low temperature fuel cells

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    Pt(Ni)/C and PtRu(Ni)/C catalysts were synthesized by electroless deposition of Ni on a carbon dispersion followed by sequenced Pt deposition and spontaneous deposition of Ru species. The structural analyses of the catalysts with 88:12 and 98:2 Pt:Ni atomic ratios pointed out to the formation of small hexagonal Ni crystallites covered by thin cubic Pt surface structures with no evidence about PtNi alloy formation. The onset potentials for CO oxidation on Pt(Ni)/C and PtRu(Ni)/C were about 0.10 and 0.24 V more negative than those of Pt/C, thus indicating their better CO tolerance. The surface Ru species appeared to have the major effect by facilitating the CO removal by the bifunctional mechanism. The onset potential for the methanol oxidation reaction (MOR) of Pt(Ni)/C was about 0.15 V lower than that of Pt/C. The mass and specific activities together with the exchange current densities of the Pt(Ni)/C catalysts were also higher than those of Pt/C, making in evidence their higher activity in front of the MOR. The Tafel slopes for the MOR on Pt(Ni)/C suggested different reaction mechanism than on Pt/C. The electronic (ligand) effect of Ni on Pt was considered the main reason to explain the higher activity of Pt(Ni)/C in front of the CO oxidation and the MOR

    Electrochemical performance of carbon-supported Pt(Cu) electrocatalysts for low-temperature fuel cells

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    Pt(Cu) nanoparticles supported on carbon nanofibers (CNFs), multi-walled carbon nanotubes (MWCNTs) and Vulcan carbon XC72, have been synthesized by electroless deposition and galvanic exchange. The structural analyses show contracted Pt fcc lattices due to the formation of a PtCu alloy core covered by a Pt-rich shell, mean crystallite sizes of about 3 nm, as well as good dispersion and carbon attachment. The electrochemical surface areas (ECSAs) of Pt(Cu)/CNF and Pt(Cu)/XC72 are comparable to those of commercial Pt/C and PtCu/C. The Pt(Cu) electrocatalysts show more negative onset potentials for CO oxidation than Pt/C and PtCu/C, thus indicating their greater CO tolerance. Pt(Cu)/CNF and Pt(Cu)/MWCNT present the highest mass activity and specific activity for the O2 reduction, respectively, both with better relative stability than Pt(Cu)/XC72. Pt(Cu)/CNF and Pt(Cu)/MWCNT are then considered good cathode catalysts, yielding estimated savings of about 50 wt.% Pt, when applied to low-temperature fuel cells

    Home parenteral nutrition (HPN) registry in spain for the years 2007, 2008 and 2009 (Nadya-SENPE group)

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    Objetivo: Comunicar los datos del registro de Nutrición Parenteral Domiciliaria (NPD) del grupo de trabajo NADYA-SENPE de los años 2007, 2008 y 2009. Material y métodos: Recopilación de los datos del registro “on-line” introducidos por las Unidades responsables del seguimiento de la NPD desde el 1 de enero de 2007 al 31 de diciembre de 2009 dividido por años naturales. Resultados: Año 2007: Se registraron 133 pacientes con NPD (61 hombres y 72 mujeres), de 21 hospitales. La edad media de los 119 pacientes mayores de 13 años fue de 53,7 ± 14,9 años, y de 3,6 ± 3,6 años la de los 14 pacientes que no los superaban. La patología más frecuente fue la neoplasia (24%) seguida de las alteraciones de la motilidad intestinal y la enteritis posradiación (ambas 14%). En el 43% de los casos el motivo de indicación fue el síndrome de intestino corto, seguido de malabsorción (27%) y obstrucción intestinal (23%). Los catéteres más utilizados fueron los tunelizados (69%) y los reservorios subcutáneos (27%). Las complicaciones mas frecuentes fueron las sépticas relacionadas con el catéter con una tasa de 0,92 infecciones por cada mil días de NPD. La duración de la NPD fue superior a los dos años en el 50% de los casos. Al acabar el año seguía en activo el 71,4% de los pacientes; la muerte fue la principal causa de la finalización de la NPD (57,5%). El 26% de los pacientes se consideraron candidatos al trasplante intestinal. Año 2008: Se registraron 143 pacientes con NPD (62 hombres y 81mujeres), de 24 hospitales. La edad media de los 133 pacientes mayores de 13 años fue de 54,7 ± 13,9 años, y de 3,7 ± 0,6 años la de los 10 pacientes que no los superaban. La patología más frecuente fue la neoplasia (20%) seguida de la enteritis rádica (14%) y las alteraciones de la motilidad intestinal (13%). En el 44% de los casos el motivo de indicación fue el síndrome de intestino corto, seguido de malabsorción (28%) y obstrucción Nutriintestinal (20%). Los catéteres más utilizados fueron los tunelizados (60%) y los reservorios subcutáneos (29%). Las complicaciones mas frecuentes fueron las sépticas relacionadas con el catéter con una tasa de 0,50 infecciones por cada mil días de NPD. La duración de la NPD fue superior a los dos años en el 67% de los casos. Al acabar el año seguía en activo el 71,6% de los pacientes; la muerte fue la principal causa de la finalización de la NPD (52,4%). El 29% de los pacientes se consideraron candidatos al trasplante intestinal. Año 2009: Se registraron 158 pacientes con NPD (62 hombres y 96 mujeres), de 24 hospitales. La edad media de los 149 pacientes mayores de 13 años fue de 55,2 ± 13,0 años. La patología más frecuente fue la neoplasia (25%) seguida de la enteritis rádica (12%) y las alteraciones de la motilidad intestinal (11%). En el 42% de los casos el motivo de indicación fue el síndrome de intestino corto, seguido de malabsorción y obstrucción intestinal (ambas 23%). Los catéteres más utilizados fueron los tunelizados (60%) y los reservorios subcutáneos (36%). Las complicaciones mas frecuentes fueron las sépticas relacionadas con el catéter con una tasa de 0,67 infecciones por cada mil días de NPD. La duración de la NPD fue superior a los dos años en el 58% de los casos. Al acabar el año seguía en activo el 79,2% de los pacientes; el paso a alimentación oral fue la principal causa de la finalización de la NPD (48%). El 23% de los pacientes se consideraron candidatos a trasplante intestinal. Conclusiones: Se observa un aumento progresivo de los pacientes registrados respecto a años anteriores con una prevalencia muy variable según comunidades autónomas. La principal patología sigue siendo la neoplasia, que ocupa el primer lugar desde 2003. Se aprecia una disminución de las complicaciones sépticas relacionadas con el catéter en los dos últimos años, siendo la tasa de 2008 la más baja desde la creación del registroObjective: To report the data of the Home Parenteral Nutrition (HPN) registry of the NADYA-SENPE working group for the years 2007, 2008 and 2009. Methodology: We compiled the data from the on-line registry introduced by the responsible Units for the monitoring of HPN from January 1st 2007 to December 31st 2009. Included fields were: age, sex, diagnosis and reason for HPN, access path, complications, beginning and end dates, complementary oral or enteral nutrition, activity level, autonomy degree, product and fungible material supply, withdrawal reason and intestinal transplant indication. Results: 2007: 133 patients with HPN were registered (61 males and 72 females), belonging to 21 hospitals. Average age for the 119 patients older than 13 years old was 53.7 ± 14.9 years, and 3.6 ± 3.6 y. for the 14 patients under 14 years old. Most frequent pathology was neoplasm (24%), followed by intestinal motility disorders and actinic enteritis (14% both). The reason for HPN provision was short bowel syndrome (43%), malabsorption (27%), and intestinal obstruction (23%). Tunnelled catheters were mostly used (69%), followed by implanted port-catheters (27%). Catheter related infections were the most frequent complications, with a rate of 0.92 episodes/103 HPN days. HPN was provided for more than two years in 50% of the cases. By the end of 2007, 71.4% of the patients remained active; exitus was the most frequent reason to end HPN (57.5%). 26% of the patients were eligible for intestinal transplant. 2008: 143 patients with HPN were registered (62 males and 81 females), belonging to 24 hospitals. Average age for the 133 patients older than 13 years old was 54.7 ± 13.9 years, and 3.7 ± 0.6 y. for the 10 patients under 14 years old. Most frequent pathology was neoplasm (20%), followed by actinic enteritis (14%) and intestinal motility disorders (13% ). The reason for HPN provision was short bowel syndrome (44%), malabsorption (28%), and intestinal obstruction (20%). Tunnelled catheters were mostly used (60%), followed by implanted port-catheters (29%). Catheter related infections were the most frequent complications, with a rate of 0.50 episodes/103 HPN days. HPN was provided for more than two years in 67% of the cases. By the end of 2008, 71.6% of the patients remained active; exitus was the most frequent reason to end HPN (52.4%). 29% of the patients were eligible for intestinal transplant. 2009: 158 patients with HPN were registered (62 males and 96 females), belonging to 24 hospitals. Average age for the 149 patients older than 13 years old was 55.2 ± 13.0 years. Most frequent pathology was neoplasm (25%), followed by actinic enteritis (12%) and intestinal motility disorders (11%). The reason for HPN provision was short bowel syndrome (42%), malabsorption, and intestinal obstruction (23% both). Tunnelled catheters were mostly used (60%), followed by implanted port-catheters (36%). Catheter related infections were the most frequent complications, with a rate of 0.67 episodes/103 HPN days. HPN was provided for more than two years in 58% of the cases. By the end of 2009, 79.2% of the patients remained active; full oral nutrition was the most frequent reason to end HPN (48%). 23% of the patients were eligible for intestinal transplant. Conclusions: We observe an increase in registered patients with respect to previous years, with a very different prevalence among regions. Neoplasia remains as the main pathology since 2003. We observe a decrease in catheter-related infections in the last two years, being the 2008 rate the smallest since the register’s beginning

    Research advances in Risaralda. An overview of 8 experiences

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    I am honored to present to you this remarkable book, a testament to the invaluable research conducted in the fields of Health, Law, Engineering, and Administrative Sciences. Each chapter within these pages represents the culmination of extensive investigations carried out by dedicated scholars affiliated with the Red Universitaria de Risaralda (RUN), a network comprising 15 esteemed higher education institutions. Risaralda has emerged as a thriving hub for higher education, bolstered by its strategic geographical location, high quality of life, rich biodiversity, and competitive development. Today, Pereira ranks third in the index of university cities, with a student enrollment rate exceeding 63%. Close to 50,000 students pursue academic programs within the department. Notably, three institutions have achieved accreditation for their excellence in education, positioning Risaralda among the most competitive regions in terms of accredited academic programs. As we celebrate the 20th anniversary of the Red Universitaria de Risaralda in 2023, it is with great pride that we reflect on its pivotal role in fostering collaboration among public and private higher education institutions. Our mission has been twofold: attracting students to our region and supporting sustainable development and quality of life for our community. The mesa de investigación (research committee) has diligently coordinated the necessary actions to unite our researchers, facilitating an integrated approach to various disciplines and themes associated with the challenges faced in our region.CONTENT Introduction...................................................................................................................5 CHAPTER ONE. Tobacco Use and Social Skills in Children from Two Schools in Pereira, Colombia .......................................................................................................9 Angélica María Blanco Vanegas, Natalia Jeaneth Carmona Valencia and Ángela Liceth Pérez Rendón CHAPTER TWO. Lesbian visibility: between control and family silence.................................................35 Mireya Ospina Botero and Carolina Carmona Castilla CHAPTER THREE. New centralities in the city of Pereira, 1990-2019 .......................................................65 Cesar Augusto Castaño Galvis CHAPTER FOUR. Bibliometric analysis of scientific publications on the effect of roots on slope stability ...........................................................................................................95 Alejandro Alzate Buitrago, Raúl Alberto Gaviria Valencia, César Augusto Peñuela Meneses, Carlos Alberto Ospina Parra CHAPTER FIVE. Sustainability of local agri-food systems in a municipality of the Eje Cafetero, Colombia...............................................................................................131 Jaime Cardona Ocampo, Orlando Ospina Salazar and Julia Arredondo Botero CHAPTER SIX. Organizational strategies aimed at the Emberá Chamí unified indigenous reservation, Inamurcito community located in the municipality of Pueblo Rico, Risaralda............................................................................................................163 Carla Johana Martínez García and Yenny Marcela Vélez Herrera CHAPTER SEVEN. Psychomotor profile of children between 4 and 5 years old in the city of Pereira, Colombia ...................................................................................................199 Jhonatan Gonzalez-Santamaría and Claudia Jimena Lopez-Garcia CHAPTER EIGHT. Analysis of assembly tasks without the use of vision: an opportunity for the design of support technologies in manufacturing environments.....................217 Gustavo Adolfo Peña Marín, Carlos Andrés Quintero Diaztagle and Juan Diego Gallego Góme

    Spanish home enteral nutrition registry of the year 2014 and 2015 from the NADYA-SENPE Group

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    Objetivo: exponer los resultados del registro de nutrición enteral domiciliaria (NED) del año 2014 y 2015 del Grupo NADYA-SENPE. Métodos: se recopilaron los pacientes introducidos en el registro desde el 1 de enero al 31 de diciembre de 2014 y la mismas fechas de 2015, y se procedió al análisis descriptivo y analítico de los datos. Resultados: en el año 2014, se registraron 3.749 pacientes y en 2015, 4.202; la prevalencia fue de 80,58 pacientes/millón de habitantes en el año 2014 y de 90,51 en 2015. Por sexos, hubo un 49,9% de mujeres en 2014 y un 50,3% en 2015. La edad media fue de 73 años (IIQ 59-83) en ambos años. Finalizaron 684 episodios de NED en 2014 y 631 en 2015, la causa principal fue el fallecimiento en el 54,9% y 50,4% de los casos, respectivamente. Los portadores de sonda nasogástrica presentan una edad media superior a los pacientes con cualquier otra vía (p < 0,001). Se registraron 67 pacientes pediátricos en 2014 (56,7% niñas) y 77 en 2015 (55,8% niñas). La vía principal de administración fue la gastrostomía en el 52,0% de los casos de 2014 y sonda nasogástrica en el 50,8% de los casos de 2015. La causa principal de fi nalización de la nutrición fue el fallecimiento (57,1% en 2014 y 38,5% en 2015). Se observó que los niños más pequeños eran los que se alimentaban preferentemente por SNG (p 0,004 vs. 0,002).Tanto en pacientes pediátricos como en adultos el diagnóstico principal que motivó la necesidad de NED fue la enfermedad neurológica que cursa con afagia o disfagia severa. Conclusiones: se ha incrementado el número de pacientes del registro, así como el número de centros participantes y el número medio de pacientes comunicados por cada centro respecto a años anteriores, sin que se hayan modificado sustancialmente las características de los pacientes, salvo mayor duración de los episodiosObjective: To present the results of the Spanish home enteral nutrition (HEN) registry of the NADYA-SENPE group for the years 2014 and 2015. Methods: From January 1st 2014 to December 31st 2015 the HEN registry was recorded and afterwards a further descriptive and analytical analysis was done. Results: In 2014, 3749 patients were recorded, and 4202 in 2015; prevalence was 80.58 patients/one million inhabitants in Spain in 2014 and 90.51 in 2015. There were 49.9% females in 2014 and 50.3% in 2015. Median age was 73 years (IQI 59-83) in 2014 as well as in 2015. 684 episodes fi nished in 2014 and 631 in 2015, with death as the main cause, in 54.9% and 50.4%, respectively. The ones who were fed through nasogastric tube had a mean age higher than the ones fed by any other route (p-value < 0.001). Sisty-seven paediatric patients were recorded in 2014 (56.7% females) and 77 in 2015 (55.8% females). Median age at the beginning of HEN among children was 5 months in 2014 and 5 months in 2015. The main route of administration was gastrostomy, in 52.5% in 2014 and nasogastric tube in 50.8% in 2015. 7 episodes fi nished in 2014 and 13 in 2015, having death as the main cause (57.1% in 2014 and 38.5% in 2015). It was found that were younger children the ones who were mainly fed by nasogastric tubes (p-value 0.004 vs. 0.002). Among paediatric patients as well as adults, the main diagnosis leading to HEN was neurological disease which gives aphagia or severe dysphagia. Conclusions: There has been an increase in the number of patients in the registry as well as the participating centers and the number of patients per center, without any signifi cant change in the characteristics of the patients other than longer duration of the episode

    Nutrición parenteral domiciliaria en España, 2019: informe del Grupo de Nutrición Artificial Domiciliaria y Ambulatoria NADYA

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    RESUMEN Objetivo: comunicar los datos de nutrición parenteral domiciliaria (NPD) obtenidos del registro del grupo NADYA-SENPE (www.nadyasenpe.com) del año 2019. Material y métodos: análisis descriptivo de los datos recogidos de pacientes adultos y pediátricos con NPD en el registro NADYA-SENPE desde el 1 de enero al 31 de diciembre de 2019. Resultados: se registraron 283 pacientes (51,9 %, mujeres), 31 niños y 252 adultos procedentes de 47 hospitales españoles, lo que representa una tasa de prevalencia de 6,01 pacientes/millón de habitantes/año 2019. El diagnóstico más frecuente en los adultos fue “oncológico paliativo” y “otros” (21,0 %). En los niños fue la enfermedad de Hirschsprung junto a la enterocolitis necrotizante, las alteraciones de la motilidad intestinal y la pseudoobstrucción intestinal crónica, con 4 casos cada uno (12,9 %). El primer motivo de indicación fue el síndrome del intestino corto tanto en los niños (51,6 %) como en los adultos (37,3 %). El tipo de catéter más utilizado fue el tunelizado tanto en los niños (75,9 %) como en los adultos (40,8 %). Finalizaron 68 episodios, todos en adultos: la causa más frecuente fue el fallecimiento (54,4 %). Pasaron a la vía oral el 38,2 %. Conclusiones: el número de centros y profesionales colaboradores con el registro NADYA va incrementándose. Se mantienen estables las principales indicaciones y los motivos de finalización de la NPD

    Serological response and breakthrough infection after COVID-19 vaccination in patients with cirrhosis and post-liver transplant

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    BACKGROUND: Vaccine hesitancy and lack of access remain major issues in disseminating COVID-19 vaccination to liver patients globally. Factors predicting poor response to vaccination and risk of breakthrough infection are important data to target booster vaccine programs. The primary aim of the current study was to measure humoral responses to 2 doses of COVID-19 vaccine. Secondary aims included the determination of factors predicting breakthrough infection. METHODS: COVID-19 vaccination and Biomarkers in cirrhosis And post-Liver Transplantation is a prospective, multicenter, observational case-control study. Participants were recruited at 4-10 weeks following first and second vaccine doses in cirrhosis [n = 325; 94% messenger RNA (mRNA) and 6% viral vaccine], autoimmune liver disease (AILD) (n = 120; 77% mRNA and 23% viral vaccine), post-liver transplant (LT) (n = 146; 96% mRNA and 3% viral vaccine), and healthy controls (n = 51; 72% mRNA, 24% viral and 4% heterologous combination). Serological end points were measured, and data regarding breakthrough SARS-CoV-2 infection were collected. RESULTS: After adjusting by age, sex, and time of sample collection, anti-Spike IgG levels were the lowest in post-LT patients compared to cirrhosis (p < 0.0001), AILD (p < 0.0001), and control (p = 0.002). Factors predicting reduced responses included older age, Child-Turcotte-Pugh B/C, and elevated IL-6 in cirrhosis; non-mRNA vaccine in AILD; and coronary artery disease, use of mycophenolate and dysregulated B-call activating factor, and lymphotoxin-α levels in LT. Incident infection occurred in 6.6%, 10.6%, 7.4%, and 15.6% of cirrhosis, AILD, post-LT, and control, respectively. The only independent factor predicting infection in cirrhosis was low albumin level. CONCLUSIONS: LT patients present the lowest response to the SARS-CoV-2 vaccine. In cirrhosis, the reduced response is associated with older age, stage of liver disease and systemic inflammation, and breakthrough infection with low albumin level

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality
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