226 research outputs found

    Nature and Location of Carbonaceous Species in a Composite HZSM-5 Zeolite Catalyst during the Conversion of Dimethyl Ether into Light Olefins

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    The deactivation of a composite catalyst based on HZSM-5 zeolite (agglomerated in a matrix using boehmite as a binder) has been studied during the transformation of dimethyl ether into light olefins. The location of the trapped/retained species (on the zeolite or on the matrix) has been analyzed by comparing the properties of the fresh and deactivated catalyst after runs at different temperatures, while the nature of those species has been studied using different spectroscopic and thermogravimetric techniques. The reaction occurs on the strongest acid sites of the zeolite micropores through olefins and alkyl-benzenes as intermediates. These species also condensate into bulkier structures (polyaromatics named as coke), particularly at higher temperatures and within the mesoand macropores of the matrix. The critical roles of the matrix and water in the reaction medium have been proved: both attenuating the effect of coke deposition.The financial support of this work was undertaken by the Ministry of Economy and Competitiveness of the Spanish Government, some cofounded with ERDF funds (Project CTQ2013-46172-P, CTQ2013-46173-R and CTQ2016-79646-P projects), by the Basque Government (Project IT748-13) and by the University of the Basque Country (UFI 11/39). M. Ibafiez is grateful for the postgraduate grant from the University of the Basque Country (No. UPV/EHU2016)

    PRIMER REGISTRO DEL TIGRILLO (LEOPARDUS WIEDII, SCHINZ 1821) Y DEL GATO MONTÉS (LYNX RUFUS, KERR 1792) EN LA RESERVA DE LA BIÓSFERA DE TEHUACÁN-CUICATLÁN, OAXACA, MÉXICO

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    Using camera-traps, two new records of margay (Leopardus wiedii) and two of lynx (Lynx rufus) were obtained at the Biosphere Reserve de Tehuacán-Cuicatlán, Oaxaca, Mexico, in 2003 and 2004. These are the first records documenting the presence of both species in this reserve

    Risk factors for major adverse cardiovascular events in postmenopausal women: UK Biobank prospective cohort study

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    Background and aims Cardiovascular risk increases during menopause, so the medical and scientific community should consider women's specific risk factors to prevent cardiovascular disease. This study aims to assess the risk factors for the incidence of major adverse cardiovascular events (MACE) exclusive to postmenopausal women. Methods We conducted a prospective cohort study in postmenopausal women aged 40 years and older, who were included in the UK Biobank cohort between 2006 and 2010 and followed to 2021 (12 years). A total of 156,787 women were followed for a median of 12.5 years (nearly 2 million person-years), and MACE risk was assessed using Fine-Gray competing risk models. Results The cumulative incidence of cardiovascular morbidity and mortality was 1.2% (0.97 cases per 1000 women-years). Not having taken birth control pills, not having children, and early menarche (≤12 years) were independently associated with cardiovascular morbidity and mortality. Conclusions Risk factors for cardiovascular disease that are specific to women include early menarche, not having taken oral contraceptives, and reproductive history, and this relationship is independent of classic cardiovascular risk factors

    Factors affecting nectar sugar composition in chiropterophilic plants

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    AbstractMost pollinators prefer the sugars present in the nectar they consume, so it has been hypothesized that they have molded nectar trait evolution. However, nectar-feeding bats do not exhibit preferences for the sugars present in their diet. We analyzed the role that biochemical and ecological factors could play in shaping the nectar traits of chiropterophilic plants. We studied nectar traits and flower production in 49 plant species. We evaluated the relationship between nectar concentration and sugar composition using phylogenetically independent contrasts and if nectar traits were related to flower production using a Manova. We found that 42 species produced high hexoses nectars, and 7 species produced sucrose rich nectars. Phylogenetically independent contrasts showed that nectar concentration was negatively related to glucose content, positively related to fructose content, and was not related to sucrose content. A negative relationship was found from glucose and fructose contents to sucrose content, and glucose content was negatively related to fructose content. Finally, we did not found any relationship between nectar traits and the plants’ flowering strategies. We conclude that bat physiology and the relative low evolutionary time of the interaction between plants and bats may determine the lack of pattern in the nectar characteristics of chiropterophilic plants

    Acute oxidant damage promoted on cancer cells by amitriptyline in comparison with some common chemotherapeutic drugs

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    Oxidative therapy is a relatively new anticancer strategy based on the induction of high levels of oxidative stress, achieved by increasing intracellular reactive oxygen species (ROS) and/or by depleting the protective antioxidant machinery of tumor cells. We focused our investigations on the antitumoral potential of amitriptyline in three human tumor cell lines: H460 (lung cancer), HeLa (cervical cancer), and HepG2 (hepatoma); comparing the cytotoxic effect of amitriptyline with three commonly used chemotherapeutic drugs: camptothecin, doxorubicin, and methotrexate. We evaluated apoptosis, ROS production, mitochondrial mass and activity, and antioxidant defenses of tumor cells. Our results show that amitriptyline produces the highest cellular damage, inducing high levels of ROS followed by irreversible serious mitochondrial damage. Interestingly, an unexpected decrease in antioxidant machinery was observed only for amitriptyline. In conclusion, based on the capacity of generating ROS and inhibiting antioxidants in tumor cells, amitriptyline emerges as a promising new drug to be tested for anticancer therapy

    Crecimiento de pasto Guinea (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs) en respuesta a fertilización química en clima cálido húmedo

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    Objective: To determine the dynamics of growth in Guinea grass (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs) cv. Mombasa in response to the application of different doses of chemical fertilization with nitrogen (N), phosphorus (P) and potassium (K) in humid tropical climate conditions. Design/methodology/approach: The experiment was done in Loma Bonita, Oaxaca, Mexico. A plot of Guinea grass was established. Previously, a cut of uniform was done 15 cm above of soil level. Fertilizer treatments were applied based on chemical fertilization with N, P and K. The treatments were: T1=00-00-00, T2=100-00-00, T3=140-20-00, T4=180-40-20, T5=200-00-00, T6=240-40-20, T7=260-60-40, T8=300-00-00 of N:P:K. The response variables were: plant height (cm), dry matter accumulation (kg ha?1) and Chlorophyll content using the Chlorophyll meter SPAD-502 of MinoltaMR. Analysis of variance and mean comparison by Tukey (P£0.05) was realized.Results: The results suggest that fertilization treatments with the highest contents in N, P and K favored the height of plant, the content of Chlorophyll in leaves and the accumulation of dry matter per hectare.Limitations on study/implications: Applying fertilizer is a good alternative way to improve the growth and performance of Guinea grass. Nevertheless, a major number of environmental conditions and annual periods of investigation are required for the obtained results in different livestock zones. Findings/conclusions: The major plant eight was find used the fertilization 140-20-00, the chlorophyll content is high when the formula 260-60-40 is used. Dry matter is better if high doses of N (300-00-00) are used in Guinea grass.Objetivo: Determinar la dinámica de crecimiento de pasto Guinea (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs) cv. Mombasa con diferentes dosis de nitrógeno (N), fósforo (P) y potasio (K) en clima cálido húmedo. Diseño/metodología/aproximación. El experimento se realizó en Loma Bonita, Oaxaca, México, se estableció una pradera de pasto Guinea. Antes de iniciar la investigación se efectuó un corte de uniformidad a 15 cm de altura, y en etapa de emisión de macollos se fertilizó con N, P y K. Los tratamientos evaluados fueron las combinaciones: 00-00-00, 100-00-00, 140-20-00, 180-40-20, 200-00-00, 240-40-20, 260-60-40, 300-00-00 de N: P: K, respectivamente. Las variables evaluadas fueron: altura de planta (cm), acumulación de materia seca (kg ha-1) y contenido de clorofila con el SPAD-502 de MinoltaMR. Se hizo un análisis de varianza y prueba de comparación de medias por Tukey (P£0.05). Resultados: Los resultados indican que los tratamientos de fertilización con las fórmulas más altas en N, P y K, favorecieron la altura de la planta, el contenido de clorofila en hojas y la acumulación de materia seca por hectárea. Limitaciones del estudio/implicaciones: La fertilización química es una alternativa para mejorar el crecimiento y rendimiento de pasto Guinea; no obstante, se requiere utilizar un mayor número de ambientes y épocas del año para validar los resultados obtenidos en diferentes regiones ganaderas. Hallazgos/conclusiones: La mayor altura de planta se registró con la fórmula 140-20-00, el contenido de clorofila aumentó cuando se utilizó la fórmula 260-60-40 y la producción de materia seca mejoró al aplicar la dosis más alta de N (300-00-00)

    Apoptotic microtubules delimit an active caspase free area in the cellular cortex during the execution phase of apoptosis

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    Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath plasma membrane, which has an important role in preserving cell morphology and plasma membrane permeability. The aim of this study was to examine the role of AMN in maintaining plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptosis in H460 cells that AMN delimits an active caspase free area beneath plasma membrane that permits the preservation of cellular cortex and transmembrane proteins. AMN depolymerization in apoptotic cells by a short exposure to colchicine allowed active caspases to reach the cellular cortex and cleave many key proteins involved in plasma membrane structural support, cell adhesion and ionic homeostasis. Cleavage of cellular cortex and plasma membrane proteins, such as a-spectrin, paxilin, focal adhesion kinase (FAK), E-cadherin and integrin subunit b4 was associated with cell collapse and cell detachment. Otherwise, cleavage-mediated inactivation of calcium ATPase pump (PMCA-4) and Naþ/Ca2þ exchanger (NCX) involved in cell calcium extrusion resulted in calcium overload. Furthermore, cleavage of Naþ/Kþ pump subunit b was associated with altered sodium homeostasis. Cleavage of cell cortex and plasma membrane proteins in apoptotic cells after AMN depolymerization increased plasma permeability, ionic imbalance and bioenergetic collapse, leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the concomitant addition of colchicine that induces AMN depolymerization and the pan-caspase inhibitor z-VAD avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Furthermore, the presence of AMN was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that AMN is essential to preserve an active caspase free area in the cellular cortex of apoptotic cells that allows plasma membrane integrity during the execution phase of apoptosis

    Pruning height and frequency of Moringa oleifera and Leucaena leucocephala in a silvopastoral system

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    Objetive: Evaluate two heights (50 and 70 cm) and pruning frequencies (60 and 135 d) in Moringa oleifera and Leucaena leucocephala in a developing silvopastoral system. Desing/methodology/approach: Four treatments were established, T1: Moringa oleifera with pruning at 50 cm, T2: Moringa oleifera with pruning at 70 cm, T3: Leucaena leucocephala with pruning at 50 cm and T4: Leucaena leucocephala with pruning at 70 cm and pruning frequencies at the 60 and 135 d. The number of sprouts, diameter and length of the largest sprout, and biomass were recorded. The data were analyzed using a mixed model, analysis of variance and Tukey's tests. Results: The number of regrowths in L. leucocephala was higher than M. oleifera. The T2 had the highest behavior at 60 d, for L. leucocephala it was similar between pruning and frequencies. The diameter and length were greater for T2 at both frequencies, at 60 d for T3 and at 135 d for T4. Biomass was higher in M. oleífera than L. leucocephala, pruning at 70 cm was better than at 50 cm. Pruning at 135 days obtained higher biomass than at 60 days. T2 obtained higher biomass at 60 d, T1 and T4 at 135 d. Study limitations/implications: Forage species, frequencies and pruning heights determine the growth potential and amount of biomass available to the animals. Findings/conclusions:Leucaena leucocephala has better agronomic performance in response to pruning without influencing the height and frequency of pruning in a silvopastoral system.Objective: To evaluate two different heights (50 and 70 cm) and pruning frequencies (60 and 135 days) in Moringa oleifera and Leucaena leucocephala in a developing silvopastoral system. Design/methodology/approach: Four treatments were established: T1=Moringa oleifera with pruning at 50 cm; T2=Moringa oleifera with pruning at 70 cm; T3=Leucaena leucocephala with pruning at 50 cm; and T4=Leucaena leucocephala with pruning at 70 cm. In all cases, pruning frequencies were 60 and 135 days. The number of sprouts, diameter, and length of the largest sprout, as well as the amount of biomass, were recorded. A mixed model, variance analysis, and Tukey's test were used to analyze the data. Results: The number of regrowths for L. leucocephala was higher than for M. oleifera. Treatment T2 had the highest performance at day 60; in the case of L. leucocephala, performance was similar between pruning frequencies. For T2, diameter and length were larger at both frequencies; for T3, at 60 days; and for T4, at 135 days. Biomass was higher for M. oleifera than for L. leucocephala, while pruning at 70 cm was better than at 50 cm. Pruning at 135 days produced a higher biomass than at 60 days. For T2, biomass was higher at 60 days, while for T1 and T4, it was higher at 135 days. Study limitations/implications: Forage species, as well as pruning frequencies and heights, determine tree growth potential and the amount of biomass available for animals. Findings/conclusions: The agronomic performance of Leucaena leucocephala has a better response to pruning, regardless of pruning height and frequency, in a silvopastoral system

    Apoptotic microtubules delimit an active caspase free area in the cellular cortex during the execution phase of apoptosis

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    This work is licensed under the Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 Unported License.Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath plasma membrane, which has an important role in preserving cell morphology and plasma membrane permeability. The aim of this study was to examine the role of AMN in maintaining plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptosis in H460 cells that AMN delimits an active caspase free area beneath plasma membrane that permits the preservation of cellular cortex and transmembrane proteins. AMN depolymerization in apoptotic cells by a short exposure to colchicine allowed active caspases to reach the cellular cortex and cleave many key proteins involved in plasma membrane structural support, cell adhesion and ionic homeostasis. Cleavage of cellular cortex and plasma membrane proteins, such as α-spectrin, paxilin, focal adhesion kinase (FAK), E-cadherin and integrin subunit β4 was associated with cell collapse and cell detachment. Otherwise, cleavage-mediated inactivation of calcium ATPase pump (PMCA-4) and Na(+)/Ca(2+) exchanger (NCX) involved in cell calcium extrusion resulted in calcium overload. Furthermore, cleavage of Na(+)/K(+) pump subunit β was associated with altered sodium homeostasis. Cleavage of cell cortex and plasma membrane proteins in apoptotic cells after AMN depolymerization increased plasma permeability, ionic imbalance and bioenergetic collapse, leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the concomitant addition of colchicine that induces AMN depolymerization and the pan-caspase inhibitor z-VAD avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Furthermore, the presence of AMN was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that AMN is essential to preserve an active caspase free area in the cellular cortex of apoptotic cells that allows plasma membrane integrity during the execution phase of apoptosis.This work was supported by FIS PI10/00543 grant, FIS EC08/00076 grant, Ministerio de Sanidad, Spain and Fondo Europeo de Desarrollo Regional (FEDER-Unión Europea), SAS 111242 grant, Servicio Andaluz de Salud Junta de Andalucía, Proyecto de Investigación de Excelencia de la Junta de Andalucía CTS-5725, and by AEPMI (Asociación de Enfermos de Patología Mitocondrial).Peer reviewe
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