Synthesis, characterization of a new carbonylated zirconium metallocene using a dichloro-zirconocene derived from partially alkylated s-indacene

Indexación: ScieloThis work describes the synthesis and characterization of new organometallic species, an unprecedented mononuclear zirconium complex bearing a tetraalkylated s-indacene ligand, and secondly, its respective dicarbonyl complex obtained by reduction with Mg/HgCl2. Theoretical calculations of these two compounds were carried out to gain further understanding of these novel molecular systems.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072009000300014&lng=es&nrm=is

Thermodynamics of Higher Spin Black Holes in AdS3_3

We discuss the thermodynamics of recently constructed three-dimensional higher spin black holes in SL(N,R)\times SL(N,R) Chern-Simons theory with generalized asymptotically-anti-de Sitter boundary conditions. From a holographic perspective, these bulk theories are dual to two-dimensional CFTs with W_N symmetry algebras, and the black hole solutions are dual to thermal states with higher spin chemical potentials and charges turned on. Because the notion of horizon area is not gauge-invariant in the higher spin theory, the traditional approaches to the computation of black hole entropy must be reconsidered. One possibility, explored in the recent literature, involves demanding the existence of a partition function in the CFT, and consistency with the first law of thermodynamics. This approach is not free from ambiguities, however, and in particular different definitions of energy result in different expressions for the entropy. In the present work we show that there are natural definitions of the thermodynamically conjugate variables that follow from careful examination of the variational principle, and moreover agree with those obtained via canonical methods. Building on this intuition, we derive general expressions for the higher spin black hole entropy and free energy which are written entirely in terms of the Chern-Simons connections, and are valid for both static and rotating solutions. We compare our results to other proposals in the literature, and provide a new and efficient way to determine the generalization of the Cardy formula to a situation with higher spin charges.Comment: 30 pages, PDFLaTeX; v2: typos corrected, explicit expressions for the free energy adde

Laparoscopy and Natural Orifice Surgery: First Entry Safety Surveillance Step

Results of this study suggest that surveillance of the first entrance port in laparoscopic and natural orifice transvaginal endoscopic procedures may assist in recognizing complications that might otherwise be missed

Morphological and genetic diversity of the Balearic lizard,Podarcis lilfordi(Gunther, 1874): Is it relevant to its conservation?

Aims: To characterize the genetic and morphological diversification of the endangered Balearic lizard Podarcis lilfordi and to assess the relevance of this diversity, and how it is described, to conservation measures. Location: This study covers all the populations of the Balearic lizard, Podarcis lilfordi, present in its range of distribution at coastal islets of Menorca, Mallorca and Cabrera Archipelago. Methods: We analysed genetic and morphological variation across the 43 known extant populations of the Balearic lizard, using mitochondrial and nuclear markers. We examined morphometric and scalation characters using, in some cases, phylogenetically independent contrasts. We also incorporated the study of dorsal coloration and dorsal colour pattern including the analysis of melanism in several populations. Results: We detected clear genetic divergence between Menorcan populations and populations from Mallorca and Cabrera, in both nuclear and mtDNA markers, but genetic divergence is relatively low among different insular populations within these groups. In contrast, morphological divergence was substantial both between Menorcan and remaining populations and within these groups. Morphological traits, such as dorsal coloration, body size and the number and size of scales, seemed to be linked with differences in climatic conditions between populations. In addition, some traits, as melanism, showed a strong phylogenetic signal. Main conclusions: The morphological and genetic diversity of the Balearic lizard is incongruent with the subspecies described in the classical taxonomic literature. Moreover, current populations differ not only in some genetic and morphological features, but also in several ecological and ethological characteristics, in many cases unique to one population. Based on our results, we propose abandoning the use of subspecies to describe the extraordinary morphological diversity of the Balearic lizard and its replacement with the concept of evolutionary significant units (ESUs). ESUs are particularly suitable to describe and recognize such diversity and, especially, to ensure the continuity of the evolutionary process

Suplementación de raciones para cebo intensivo de terneros con aceites vegetales: rendimientos productivos, calidad de la canal, de la grasa y de la carne

Se han estudiado los efectos de la incorporación de aceites de origen vegetal sobre los rendimientos productivos, calidad de la canal y de la grasa en el ganado vacuno. Se utilizaron 240 terneros agrupados en 24 lotes de 10 terneros cada uno. Las raciones experimentales fueron: Tratamiento Control (4% de aceite de palma), Oliva (4,8% de jabón cálcico de aceite de oliva), Soja (4% de aceite de soja). De cada lote se seleccionó al azar un ternero (8 terneros por tratamiento) para diseccionar su 6ª costilla. No se han observado diferencias significativas entre tratamientos para ningún parámetro productivo ni de calidad de la canal. Los animales que consumieron aceite de oliva presentaron un mayor contenido (P=0,09) en C18:2 cis-9, trans-11 CLA en la grasa intramuscular que los que consumieron palma

Suplementación de raciones para cebo intensivo de terneros con aceites vegetales: calidad de carne

Se han estudiado los efectos de la incorporación de aceites de origen vegetal sobre la calidad de carne en el ganado vacuno. Se utilizaron 240 terneros agrupados en 24 lotes de 10 terneros cada uno. Las raciones experimentales fueron: Tratamiento Control (4% de aceite de palma), Oliva (4,8% de jabón cálcico de aceite de oliva), Soja (4% de aceite de soja). De cada lote se seleccionó al azar un ternero (8 terneros por tratamiento) para diseccionar su 6ª costilla. Se tomaron medidas de pH, color y textura del músculo Longissimus dorsi. Por último se realizó un análisis sensorial mediante un panel de catadores en el que se analizaron los parámetros de olor, textura y flavor de la carne. La carne de los animales alimentados con aceite de palma (Control) presentó el valor más alto (P0,05). En el análisis sensorial de la carne no se han observado diferencias significativas en los parámetros estudiados

Significance of calcium: its correlation with red and white muscle contraction, fatigue and potential

According to the predominant types of muscle fibers in an individual, they will have the ability to perform different types of exercises (both aerobic and anaerobic). To comprehend the mechanism of muscle fibers, which can act in diverse ways, enhancing either resistance or power, it is essential to examine the significance of calcium. Calcium plays a crucial role in both red and white muscle fibers. The release of calcium in white (fast-twitch) muscle fibers is significantly greater and faster, resulting in increased energy consumption, facilitating explosive physical activities. Conversely, in red (slow-twitch) muscle fibers, the release of calcium occurs in smaller amounts and over a prolonged period, leading to sustained energy consumption. The characteristics of contraction in red fibers enable endurance activities. A reduction in the amount of calcium results in diminished muscle contractile capacity, known as fatigue. The primary contributing factor, as previously mentioned, is the decline in calcium, but factors such as lactic acid and the dephosphorylation of the myosin head also contribute to its onset

Adaptación y validación de un cuestionario para medir burnout académico en estudiantes de medicina de la universidad Ricardo Palma: Adaptation and validation of a questionnaire to measure academic burnout in medical university students

Introduction: Evaluate the validity and reliability of an instrument adapted to Peru to measure pre-presenceof Burnout Syndrome in university students of the career of Human Medicine at the UniversityRicardo Palma, taking as a starting point the Burnout Inventory of Maslach - Student Survey (MBISS). Methods: Cross-sectional analytical study, with level of application research. Validity was evaluated byanalysis of factorial structure with the principal components method, Kaiser-Meyer Olkin tests and Varimax rotation were applied; the reliability by the Cronbach alpha value. Results: 223 students from the Faculty of Human Medicine of the Ricardo Palma University were included, from November to December 2016. The prevalence of academic Burnout found was 28.25% (63); The Kaiser-Meyer Olkin fitness test had a result of 0.813 and Barlett's sphericity test of 1007.5 (p <0.000). The cumulative variance explained by 3 factors was calculated to be 55.4%. The instrument obtained a Cronbach's Alpha coefficient = 0.794, with correlations between the items, Emotional Exhaustion (α =, 855), Cynicism (α = 0.623) and Academic Efficiency (α = 0.744). Conclusion: The adapted and validated instrument gathers the psychometric properties to be considered a useful and reliable instrument initially in human medicine students of the Ricardo Palma University, presenting an adequate factorial structure and internal consistency to determine the level of Burnout Syndrome Academic.   DOI 10.25176/RFMH.v19.n1.1794Introducción: Evaluar lLa validez y fiabilidad de un instrumento adaptado al Perú para medir la pre-senciadel Síndrome de Burnout en estudiantes universitarios de la carrera de Medicina Humana en la UniversidadRicardo Palma, tomando como punto de partida el Inventa-rio de Burnout de Maslach - Student Survey (MBISS). Métodos: Estudio transversal analítico, con nivel de investigación aplicativo. Se evaluó la validez poranálisis de estructura factorial con el método de componentes principales, se apli-caron las pruebas de Kaiser- Meyer Olkin y la rotación Varimax; la confiabilidad por el valor alfa de Cronbach. Resultados: Fueron incluidos 223 estudiantes de la Facultad de Medicina Humana de la Universidad Ricardo Palma, en el periodo noviembre a diciembre del año 2016. La prevalencia de Burnout académico encontrada fue 28,25% (63); La prueba de adecuación de Kaiser-Meyer Olkin tuvo un resultado de 0.813 y la prueba de esfericidad de Barlett de 1007.5 (p<0.000). Se calculó la varianza acumulada explicada por 3 factores fue de 55.4%. El instrumento obtuvo un coeficiente Alfa de Cronbach= 0,794, con correlaciones entre los ítems, Agotamiento Emocional (α= ,855), Cinismo (α=0,623) y Eficacia Académica (α= 0,744). Conclusión: El instrumento adaptado y validado reúne las propiedades psicométricas para ser con-siderado un instrumento útil y fiable inicialmente en estudiantes de medicina humana de la Universidad Ricardo Palma, presentando una adecuada estructura factorial y consistencia interna para la determinación del nivel de Síndrome de Burnout Académico.   DOI 10.25176/RFMH.v19.n1.179

Methionine adenosyltransferase S-nitrosylation is regulated by the basic and acidic amino acids surrounding the target thiol

S-Adenosylmethionine serves as the methyl donor for many biological methylation reactions and provides the propylamine group for the synthesis of polyamines. S-Adenosylmethionine is synthesized from methionine and ATP by the enzyme methionine adenosyltransferase. The cellular factors regulating S-adenosylmethionine synthesis have not been well defined. Here we show that in rat hepatocytes S-nitrosoglutathione monoethyl ester, a cell-permeable nitric oxide donor, markedly reduces cellular S-adenosylmethionine content via inactivation of methionine adenosyltransferase by S-nitrosylation. Removal of the nitric oxide donor from the incubation medium leads to the denitrosylation and reactivation of methionine adenosyltransferase and to the rapid recovery of cellular S-adenosylmethionine levels. Nitric oxide inactivates methionine adenosyltransferase via S-nitrosylation of cysteine 121. Replacement of the acidic (aspartate 355) or basic (arginine 357 and arginine 363) amino acids located in the vicinity of cysteine 121 by serine leads to a marked reduction in the ability of nitric oxide to S-nitrosylate and inactivate hepatic methionine adenosyltransferase. These results indicate that protein S-nitrosylation is regulated by the basic and acidic amino acids surrounding the target cysteine