905 research outputs found

    On the soot combustion mechanism using 3DOM ceria catalysts

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    CeO2 catalysts have been prepared with conventional (Ref) and three dimensionally order macroporous (3DOM) structures, and the effect of the structure on the soot combustion mechanism has been studied in detail. Isotopic exchange experiments showed that the CeO2-3DOM catalyst produces more active oxygen upon O2 chemisorption than the counterpart CeO2-Ref catalyst, and this active oxygen is transferred more efficiently to soot due to the macroporous structure. CeO2-3DOM and CeO2-Ref also accelerate the oxidation of NO to NO2, and their activity is equal. However, CeO2-3DOM utilizes NO2 more efficiently than CeO2-Ref for soot combustion. NO2 has two roles in the soot combustion mechanism: i) reacts with soot and ii) is chemisorbed on ceria and produces active oxygen, which is more oxidizing than NO2. In ceria catalysts with a conventional structure, the main role of NO2 is the direct oxidation of soot, because active oxygen has restrictions to be transferred from catalyst to soot due to the poor soot-catalyst solid-solid contact. However, the 3DOM structure improves the transfer of active oxygen, and therefore, an additional benefit is obtained from NO2, that is, NO2 contributes to active oxygen production and the 3DOM structure allows its efficient transference to soot.The authors thank the financial support of Generalitat Valenciana (Project PROMETEOII/2014/010), the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-67597-C2-2-R), the Spanish Ministry of Education, Culture and Sports (grant FPU14/01178) and the UE (FEDER funding)

    PrOx catalysts for the combustion of soot generated in diesel engines: effect of CuO and 3DOM structures

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    PrOx and CuO/PrOx catalysts have been prepared with conventional (Ref) and three dimensionally ordered macroporous (3DOM) structures, and the effect of the structure on soot combustion has been studied. It has been demonstrated that the 3DOM structure significantly improves the catalytic combustion of soot with O2. The activity follows the trend PrOx-3DOM > CuO/PrOx-3DOM ∼ CuO/PrOx-Ref ≫ PrOx-Ref, which is explained considering two aspects: the production of active oxygen and its transfer from catalyst to soot. FESEM microscopy, N2 adsorption, Hg porosimetry and He density show that the 3DOM catalysts have ordered macroporosity with pores of 80 nm in diameter, which favors the carbon–catalyst contact. In addition, the 3DOM catalysts present higher surface density of active oxygen (Oads), which follows the trend CuO/PrOx-3DOM > PrOx-3DOM ∼ CuO/PrOx-Ref > PrOx-Ref. Consequently, the PrOx-3DOM catalyst combines a good production of active oxygen and an efficient transfer to soot, making it the most active catalyst to accelerate soot combustion. In contrast, PrOx-Ref is the least active since it is the least efficient in producing and transferring active oxygen. The impregnation of copper with the conventional support (CuO/PrOx-Ref) enhances the production and transfer of active oxygen, improving the activity with respect to PrOx-Ref. However, CuO blocks the porosity of the 3DOM support, hindering the contact with soot. Soot combustion is accelerated in the presence of NOx due to the production of NO2. This NO2, once produced, is mostly readsorbed on the surface of the catalysts producing active oxygen that must be transferred to soot. For this reason, the porosity of the catalysts also plays a relevant role during combustion with NOx/O2 because it affects the transfer of active oxygen produced by NO2 to soot.The authors thank the financial support of the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-67597-C2-2-R and grant FJCI-2015-23769), the Spanish Ministry of Education, Culture and Sports (grant FPU14/01178) and the UE (FEDER funding)

    Sentidos e indicios de vida de las prácticas religiosas urbanas de las mujeres laicas. Estudio de casos: parroquia santa maría de la paz y parroquia San Nicolás de Bari pastoral urbana, 2011-2012.

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    La investigación enfoca los sentidos e indicios de vida de las prácticas religiosas de las mujeres que asisten a dos parroquias de la ciudad: Santa María de la Paz, ubicada en los barrios del noroeste, y San Nicolás de Bari, emplazada en la zona periférica noreste de la Ciudad de Córdoba. A modo de hipótesis se plantea la emergencia de nuevos modos de vinculación y de pertenencia a la institución parroquial de los actores sociales laicos que concurren a las mismas, mayoritariamente mujeres con niveles de instrucción medio, que presumible-mente han modificado sus modos de vivir la fe y de practicar la religión a partir de las condiciones de transformación de la cultura urbana experimentada en la Ciudad en los últimos 20 años y que dan origen, a su vez, a nuevos sentidos de la religiosidad urbana y de la construcción de las subjetividades femeninas a partir de las nuevas referencias urbanas e identitarias. El objetivo principal pretende desarrollar un trabajo interdisciplinario de análisis e interpretación de los sentidos de las prácticas de espiritualidad de los crono-topos urbanos de los laicos, particularmente de las mujeres, que asisten a estas parroquias. Se espera obtener un exhaustivo conocimiento de la realidad urbana religiosa-cultural y de las prácticas espirituales de estas dos parroquias. La realización del proyecto de investigación supone un abordaje interdisciplinario bajo una metodología hermenéutica-cualitativa que implica dos momentos: empírico (sociológico: estudio de caso)y crítico hermenéutico (teológico y filosófico)

    QUARENTA ANOS DO HERBÁRIO COR: ESTADO DA ARTE

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    O Herbário da Universidade Federal de Mato Grosso do Sul – Câmpus do Pantanal (COR) completou 40 anos em 2022. Ao longo de sua história o COR teve vários curadores e o seu acervo representa a compilação do conhecimento de cada curador ao longo de sua história. O COR possui 18.191 espécimes registrados, a maioria dos registros refere-se a plantas fanerógamas, o seu acervo conta com 14 materiais tipos, um deles, Holótipo. O acervo foi digitalizado e está disponível para toda comunidade científica. Outras atividades são desenvolvidas, como ações de extensão, atividades científicas e culturais, extensivas a toda comunidade

    Macroporous carrier-free Sr-Ti catalyst for NOx storage and reduction

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    A novel concept is presented, consisting of a macroporous carrier-free catalyst. As a proof of concept, a novel Cu-containing Sr-Ti NSR catalyst with a macroporous network has been synthesized, and its maximum NOx storage capacity (1500 μmolNOx/gcatalyst) significantly surpasses that of conventional Pt/Ba/Al2O3 formulations (∼600–800 μmolNOx/gcatalyst). This high NOx storage capacity is achieved because the active phases (mainly SrCO3 and Cu-containing Sr-Ti perovskites, as deduced by XRD) are not diluted in an inert carrier, and this can be done because the macroporous structure obtained using a polymethylmethacrylate colloidal crystal template allows the access of gases to the particles bulk. In situ DRIFTS experiments showed that NOx were chemisorbed on the novel Cu-containing Sr-Ti macroporous catalyst as a mixture of nitrite and nitro species, and this suggests that several NOx chemisorption pathways are simultaneously taking place probably involving chemisorption of both NO and NO2. Additionally, this novel catalyst is totally selective towards N2 formation as NOx reduction product, without traces of N2O nor NH3. CO2 and H2O compete with NOx for being chemisorbed on the catalyst, and this hinders the utilization of this catalyst in real diesel exhausts. However, we believe that this new concept of macroporous carrier-free catalyst could be extended to other heterogeneous catalyzed reactions or materials to avoid the diluting effect of the catalyst support.Authors thank the financial support from Generalitat Valenciana (Project PROMETEOII/2014/010), Spanish Ministry of Economy and Competitiveness (Projects MAT2014-61992-EXP and CTQ2015-67597-C2-2-R), Spanish Ministry of Education, Culture and Sports (grant FPU14/01178) and EU (FEDER funding)

    Ni/LnOx catalysts (Ln = La, Ce or Pr) for CO2 methanation

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    The effect of the LnOx support has been studied for Ni‐based CO2 methanation catalysts. 10 wt. % nickel catalysts with LaOx, CeO2 and PrOx supports have been prepared, characterized by N2 adsorption, XRD, XRF, TG‐MS (N2‐TPD and H2‐TPR) and XPS, and have been tested for CO2 methanation. The catalytic activity follows the trend Ni/CeO2 > Ni/PrOx >> Ni/LaOx, all catalysts being very selective towards CH4 formation. The activity depends both on the nature of the catalytic active sites and on the stability of the surface CO2 and H2O species. Ni/CeO2 is the most active catalyst because (i) the Ni2+‐ceria interaction leads to the formation of the highest population of active sites for CO2 dissociation, (ii) the reduced Ni0 sites where H2 dissociation takes place are the most electronegative and active, and (iii) the stability of surface CO2 and H2O species is lowest. Ni/LaOx achieves lower activity because of the strong chemisorption of H2O and CO2, which poison the catalyst surface, and because this support is not able to promote the formation of highly active sites for CO2 and H2 dissociation. The behavior of Ni/PrOx is intermediate, being slightly lower to that of Ni/CeO2 because the formation of active sites is not so efficient and because the stability of chemisorbed CO2 is slightly higher.The authors thank the financial support of Basque Government (Consolidated Group IT657-13), Spanish Ministry of Economy and Competitiveness (Projects CTQ2015-67597-C2-1-R and CTQ2015-67597-C2-2-R), and the EU (FEDER funding). ADQ thanks the Spanish Ministry of Education, Culture and Sports (grant FPU14/01178) and AQ the University of the Basque Country (grant PIF15/351)

    A questionnaire-based survey in Spain provides relevant information to improve the control of ovine coccidiosis

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    Ovine coccidiosis is a widespread intestinal parasitic disease caused by Eimeria spp. Lambs are infected by the ingestion of sporulated oocysts, experiencing diarrhea and low growth rates. Control should be based on measures to reduce infection pressure and stress on the animals as well as on appropriate diagnosis and strategic treatment. To obtain information on how control measures are implemented in the ovine sector in Spain, a questionnaire-based survey was completed in 2022 by 154 veterinarians and 173 farmers working in this sector. Coccidiosis was highlighted as a relevant disease by 34% of the respondents. The period of greatest risk seemed to differ between production systems, being mainly early after weaning (7–15 days after weaning) in meat flocks and feedlots and later (1–2 months after weaning) in dairy flocks. The absence of cleaning and disinfection measures was identified as a risk factor by 51% of the veterinarians, with 22% mentioning overcrowding of animals and 22% indicating that coccidiosis has more incidence in flocks with large number of animals. The use of laboratory diagnosis methods (fecal oocyst count) was unusual in 70 and 84% of the veterinarians and farmers, respectively. Regarding control, dairy flocks usually housed a larger number of animals under intensive conditions, and they implemented more frequently control measures for coccidiosis than meat flocks. Anticoccidial drugs were used in 79% of the flocks, and in 74–82% of them, they were applied based on clinical criteria. Comparing protocols for anticoccidial treatment among different production systems, in meat flocks, anticoccidial drugs were applied more frequently when clinical signs were observed, and coccidiostats were used for less than 28 days compared to dairy flocks. These results highlight the need for improvement in the use of anticoccidial treatments adjusted to the new regulatory framework in the EU, which in turn will rationalize the use of antimicrobial compounds and may help to mitigate the impact of coccidiosis in flocks

    Alteração da massa corporal e do consumo alimentar de ratos suplementados com whey proteins

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    Introduction: Whey proteins have received great attention because of their benefits on skeletal muscle hypertrophy, body fat reduction, performance, appetite regulation, immune system regulation, regulation of the lipid profile and the combat against metabolic stress. In this sense, their importance is often overestimated, leading athletes and physical activity individuals to consume very high doses of protein, without the guarantee of additional benefits.  Aim: For 12 weeks quantify the evolution of food intake and total body mass of Wistar rats supplemented with whey proteins with dosages of 2, 4, 6g/kg/day. Materials and methods: Approval protocol of the Ethics Committee on the Use of Animals of the Federal University of Maranhão nº 23115.014424 / 2015-54). An experimental research design was adopted with the rats being randomly distributed in 4 groups: Control Group (C), Supplemented groups (W2, W4, W6); the study was performed with 38 male Rattus novergicus Wistar rats with initial age of 60 days and body mass between 218 and 323 grams; supplementation with whey proteins dissolved in water followed the dosages 2, 4 and 6 g / kg / day supplementation was performed for 12 weeks, daily, three times a day, by volume of 5 ml, with an hour interval between each gavage. Variables were tested for distribution using the Shapiro-Wilk test (P> 0.05). The data of the feed consumption were analyzed by the ANOVA test; the classification variable was the interaction between feed consumption or body mass and supplementation (C, W2, W4, W6); the Tukey post-test was used to determine the statistical differences between the groups (C, W2, W4, W6), GraphPad Prism 7 software was used. Results: The mean intake of rations in the control group did not present a statistically significant difference in relation to the Whey 4 group at weeks 1 (p=0,3450), 2 (p=0,1027), 3 (p=0,1595), 4 (p=0,5572) and 5 (p=0,2539). There was a statistically significant difference in the increase of the total body mass of the control group compared to the Whey 4 group at weeks 10 (p=0,0454), 12 (p=0,0348) and at the final week (p=0,0138). Likewise, there was a significant statistical difference in the increase of the total body mass of the control group compared to the Whey group 6 in the final week (p=0,0048). In the same sense, there was a statistically significant difference in the total body mass increase of the Whey 2 group compared to the Whey 6 group in weeks 1 (p=0,0210), 2 (p=0,0434) and in the final week (p=0,0289). Discussion: Diets with high protein content play an important role in satiety due to its involvement with intestinal production of several anorectic hormones, which in turn stimulate the vagus nerve, promoting neuronal stimuli to the solitary tract nucleus, signaling satiety. As a result, the long-term ingestion of a high-protein diet reduces not only food intake, but also body mass and body adiposity in rats. Conclusion: Supplementation with serum whey proteins at doses of 4 and 6 g/kg/day in sedentary animals conferred stability over total body weight and a significant reduction in feed intake over 12 weeks. Supplementation with serum whey proteins at 2 g/kg/day in sedentary animals did not lead to a reduction in the average feed intake and showed a similar effect to the other doses on total body weight.Introdução: As whey proteins tem recebido grande atenção por conta de seus benefícios sobre a hipertrofia muscular esquelética, redução de gordura corporal, performance, regulação do apetite, regulação do sistema imunológico, regulação do perfil lipídico e combate ao estresse metabólico. Diante disso, a sua importância muitas vezes é superestimada, levando atletas e indivíduos praticantes de atividades físicas a consumirem doses muito elevadas de proteínas, sem a garantia de benefícios adicionais. Objetivo: Quantificar durante 12 semanas a alteração do consumo de ração e da massa corporal total de ratos wistar suplementados por whey proteins nas doses de 2, 4, 6g/kg/dia. Materiais e Métodos: Protocolo de aprovação da Comissão de Ética no Uso de Animais da Universidade Federal do Maranhão nº 23115.014424/2015-54). Foi adotado delineamento de pesquisa experimental com os ratos sendo distribuídos aleatoriamente em 4 grupos: Grupo Controle (C), Grupos suplementados (W2, W4, W6); o estudo foi realizado com 38 Rattus novergicus machos da linhagem Wistar com idade inicial de 60 dias e massa corporal entre 218 e 323 gramas; a suplementação com whey proteins dissolvidas em água seguiu as dosagens 2, 4 e 6 g/kg/dia a suplementação foi realizada durante 12 semanas, diariamente, três vezes por dia, em volume de 5ml, com uma hora de intervalo entre cada gavagem. As variáveis ​​foram testadas quanto à distribuição utilizando o teste de Shapiro-Wilk (p>0,05). Os dados do consumo de ração, foram analisados pelo teste ANOVA; a variável de classificação foi a interação entre o consumo de ração ou massa corporal e a suplementação (C, W2, W4, W6); o pós-teste de Tukey foi utilizado para determinar as diferenças estatísticas entre os grupos (C, W2, W4, W6), utilizou-se o software GraphPad Prism 7. Resultados: A média de consumo de ração no grupo controle não apresentou diferença estatística significativa em relação ao grupo Whey 4 nas semanas 1 (p=0,3450), 2 (p=0,1027), 3 (p=0,1595), 4 (p=0,5572) e 5 (p=0,2539). Houve diferença estatística significativa no aumento da massa corporal total do grupo controle em comparação ao grupo Whey 4 nas semanas 10 (p=0,0454), 12 (p=0,0348) e na semana final (p=0,0138). Do mesmo modo, houve diferença estatística significativa no aumento da massa corporal total do grupo controle em comparação ao grupo Whey 6 na semana final (p=0,0048). Nesse mesmo sentido, houve diferença estatística significativa no aumento massa corporal total do grupo Whey 2 em comparação ao grupo Whey 6 nas semanas 1 (p=0,0210), 2 (p=0,0434) e na semana final (p=0,0289). Discussão: Dietas com altos teores de proteínas desempenham um papel importante no surgimento da saciedade em função do seu envolvimento com a produção a nível intestinal de diversos hormônios anorexígenos que por sua vez estimulam o nervo vago, promovendo estímulos neuronais para o núcleo trato solitário, sinalizando saciedade. Em função disso, a ingestão a longo prazo de uma dieta rica em proteínas diminui não só a ingestão de alimentos, mas também a massa corporal e a adiposidade corporal em ratos. Conclusão: A suplementação com as proteínas do soro do leite nas doses de 4 e 6g/kg/dia em ratos sedentários conferiram estabilidade em relação a massa corporal total e redução significativa do consumo de ração ao longo de 12 semanas. A suplementação com as proteínas do soro do leite na dose de 2g/kg/dia em ratos sedentários não promoveu redução no consumo médio de ração e apresentou efeito semelhante as demais doses sobre a massa corporal total

    Alteration of food consumption and body mass of whey proteins supplemented rats

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    Introduction: Whey proteins have received great attention because of their benefits on skeletal muscle hypertrophy, body fat reduction, performance, appetite regulation, immune system regulation, regulation of the lipid profile and the combat against metabolic stress. In this sense, their importance is often overestimated, leading athletes and physical activity individuals to consume very high doses of protein, without the guarantee of additional benefits.  Aim: For 12 weeks quantify the evolution of food intake and total body mass of Wistar rats supplemented with whey proteins with dosages of 2, 4, 6g/kg/day. Materials and methods: Approval protocol of the Ethics Committee on the Use of Animals of the Federal University of Maranhão nº 23115.014424 / 2015-54). An experimental research design was adopted with the rats being randomly distributed in 4 groups: Control Group (C), Supplemented groups (W2, W4, W6); the study was performed with 38 male Rattus novergicus Wistar rats with initial age of 60 days and body mass between 218 and 323 grams; supplementation with whey proteins dissolved in water followed the dosages 2, 4 and 6 g / kg / day supplementation was performed for 12 weeks, daily, three times a day, by volume of 5 ml, with an hour interval between each gavage. Variables were tested for distribution using the Shapiro-Wilk test (P> 0.05). The data of the feed consumption were analyzed by the ANOVA test; the classification variable was the interaction between feed consumption or body mass and supplementation (C, W2, W4, W6); the Tukey post-test was used to determine the statistical differences between the groups (C, W2, W4, W6), GraphPad Prism 7 software was used. Results: The mean intake of rations in the control group did not present a statistically significant difference in relation to the Whey 4 group at weeks 1 (p=0,3450), 2 (p=0,1027), 3 (p=0,1595), 4 (p=0,5572) and 5 (p=0,2539). There was a statistically significant difference in the increase of the total body mass of the control group compared to the Whey 4 group at weeks 10 (p=0,0454), 12 (p=0,0348) and at the final week (p=0,0138). Likewise, there was a significant statistical difference in the increase of the total body mass of the control group compared to the Whey group 6 in the final week (p=0,0048). In the same sense, there was a statistically significant difference in the total body mass increase of the Whey 2 group compared to the Whey 6 group in weeks 1 (p=0,0210), 2 (p=0,0434) and in the final week (p=0,0289). Discussion: Diets with high protein content play an important role in satiety due to its involvement with intestinal production of several anorectic hormones, which in turn stimulate the vagus nerve, promoting neuronal stimuli to the solitary tract nucleus, signaling satiety. As a result, the long-term ingestion of a high-protein diet reduces not only food intake, but also body mass and body adiposity in rats. Conclusion: Supplementation with serum whey proteins at doses of 4 and 6 g/kg/day in sedentary animals conferred stability over total body weight and a significant reduction in feed intake over 12 weeks. Supplementation with serum whey proteins at 2 g/kg/day in sedentary animals did not lead to a reduction in the average feed intake and showed a similar effect to the other doses on total body weight

    The Core/E1 domain of Hepatitis C virus genotype 4a in Egypt does not contain viral mutations or strains specific for hepatocellular carcinoma

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    [EN] Background: Hepatitis C virus (HCV) infection is a well-documented etiological factor for hepatocellular carcinoma (HCC). As HCV shows remarkable genetic diversity, an interesting and important issue is whether such a high viral genetic diversity plays a role in the incidence of HCC. Prior data on this subject are conflicting. Objectives: Potential association between HCV genetic mutations or strain variability and HCC incidence has been examined through a comparative genetic analysis merely focused on a single HCV subtype (genotype 4a) in a single country (Egypt). Study design: The study focused on three HCV sequence datasets with explicit sampling dates and disease patterns. An overlapping HCV Core/E1 domain from three datasets was used as the target for comparative analysis through genetic and phylogenetic approaches. Results: Based on partial Core/E1 domain (387 bp), genetic and phylogenetic analysis did not identify any HCC-specific viral mutations and strains, respectively. Conclusions: The Core/E1 domain of HCV genotype 4a in Egypt does not contain HCC-specific mutations or strains. Additionally, sequence errors resulting from the polymerase chain reaction, together with a strong evolutionary pressure on HCV in patients with end-stage liver disease, have significant potential to bias data generation and interpretation. (C) 2011 Elsevier B.V. All rights reserved.This work was supported by NIH grants R01 DK80711 (Dr. Xiaofeng Fan), R21 AI076834 (Dr. Adrian M. Di Bisceglie) and USA and Egypt Science and Technology Joint Fund BIO6-002-004 (Dr. Adrian M. Di Bisceglie).Zhang, X.; Ryu, SH.; Xu, Y.; Elbaz, T.; Zekri, AN.; Abdelaziz, AO.; Abdel-Hamid, M.... (2011). The Core/E1 domain of Hepatitis C virus genotype 4a in Egypt does not contain viral mutations or strains specific for hepatocellular carcinoma. Journal of Clinical Virology. 52(4):333-338. https://doi.org/10.1016/j.jcv.2011.08.022S33333852
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