Detailed H-1 and C-13 NMR structural assignment and relative stereochemistry determination for three new and one known semi-synthetic sesquiterpene lactones

In this work is described a complete H-1 and C-13 NMR analysis for a group of four sesquiterpene lactones, three previously unknown. The unequivocal assignments were achieved by H-1 NMR, C-13{H-1} NMR, gCOSY. gHMQC, gHMBC and NOESY experiments and no ambiguities were left behind. All hydrogen coupling constants were measured, clarifying all hydrogen signals multiplicities. (C) 2011 Elsevier B.V. All rights reserved.

COMPLETE H-1 AND C-13 NMR STRUCTURAL ASSIGNMENTS FOR A GROUP OF FOUR GOYAZENSOLIDE-TYPE FURANOHELIANGOLIDES

Four goyazensolide-type sesquiterpene lactones - lychnofolide, centratherin, goyazensolide and goyazensolide acetate - were thoroughly studied by NMR experimental techniques. H-1 NMR, C-13 NMR {H-1}, COSY, HMQC, HMBC, J-res. and NOE experiments were performed to provide the needed structural information. Complete and unequivocal assignment, including the determination of all multiplicities, was obtained for each structure and the data collections are presented in tables.

The role of the C-terminal region of pulchellin A-chain in the interaction with membrane model systems

Pulchellin is a Ribosome Inactivating Protein containing an A-chain (PAC), whose toxic activity requires crossing the endoplasmic reticulum (ER) membrane. In this paper, we investigate the interaction between recombinant PAC (rPAC) and Langmuir monolayers of dipalmitoyl phosphatidyl glycerol (DPPG), which served as membrane model. Three catalytically active, truncated PACs with increasing deletion of the C-terminal region, possessing 244,239 and 236 residues (rPAC(244), rPAC(239) and rPAC(236)), were studied. rPAC had the strongest interaction with the DPPG monolayer, inducing a large expansion in its surface pressure-area isotherm. The affinity to DPPG decreased with increased deletion of the C-terminal region. When the C-terminal region was deleted completely (rPAC(236)), the interaction was recovered, probably because other hydrophobic regions were exposed to the membrane. Using Polarization Modulated-Infrared Reflection Absorption Spectroscopy (PM-IRRAS) we observed that at a bare air/water interface rPAC comprised mainly alpha-helix structures, the C-terminal region had unordered structures when interacting with DPPG. For rPAC(236) the alpha-helices were preserved even in the presence of DPPG. These results confirm the importance of the C-terminal region for PAC-ER membrane interaction. The partial unfolding only with preserved C-terminal appears a key step for the protein to reach the cytosol and develop its toxic activity. (C) 2011 Elsevier B.V. All rights reserved.

Prevalence and risk factors of Hepatitis C virus infection in Brazil, 2005 through 2009: a cross-sectional study

Abstract Background Hepatitis C chronic liver disease is a major cause of liver transplant in developed countries. This article reports the first nationwide population-based survey conducted to estimate the seroprevalence of HCV antibodies and associated risk factors in the urban population of Brazil. Methods The cross sectional study was conducted in all Brazilian macro-regions from 2005 to 2009, as a stratified multistage cluster sample of 19,503 inhabitants aged between 10 and 69 years, representing individuals living in all 26 State capitals and the Federal District. Hepatitis C antibodies were detected by a third-generation enzyme immunoassay. Seropositive individuals were retested by Polymerase Chain Reaction and genotyped. Adjusted prevalence was estimated by macro-regions. Potential risk factors associated with HCV infection were assessed by calculating the crude and adjusted odds ratios, 95% confidence intervals (95% CI) and p values. Population attributable risk was estimated for multiple factors using a case–control approach. Results The overall weighted prevalence of hepatitis C antibodies was 1.38% (95% CI: 1.12%–1.64%). Prevalence of infection increased in older groups but was similar for both sexes. The multivariate model showed the following to be predictors of HCV infection: age, injected drug use (OR = 6.65), sniffed drug use (OR = 2.59), hospitalization (OR = 1.90), groups socially deprived by the lack of sewage disposal (OR = 2.53), and injection with glass syringe (OR = 1.52, with a borderline p value). The genotypes 1 (subtypes 1a, 1b), 2b and 3a were identified. The estimated population attributable risk for the ensemble of risk factors was 40%. Approximately 1.3 million individuals would be expected to be anti-HCV-positive in the country. Conclusions The large estimated absolute numbers of infected individuals reveals the burden of the disease in the near future, giving rise to costs for the health care system and society at large. The known risk factors explain less than 50% of the infected cases, limiting the prevention strategies. Our findings regarding risk behaviors associated with HCV infection showed that there is still room for improving strategies for reducing transmission among drug users and nosocomial infection, as well as a need for specific prevention and control strategies targeting individuals living in poverty.

In vitro expression and antiserum production against the movement protein of Citrus leprosis virus C (CiLV-C)

Citrus leprosis, caused by Citrus leprosis virus C (CiLV-C), is currently considered the most important viral disease in the Brazilian citrus industry due to the high costs required for the chemical control of its vector, the mite Brevipalpus phoenicis. The pathogen induces a non-systemic infection and the disease is characterized by the appearance of localized lesions on citrus leaves, stems and fruits, premature fruit and leaf drop and dieback of stems. Attempts were made to promote in vitro expression of the putative cell-to-cell movement protein of CiLV-C in Escherichia coli and to produce a specific polyclonal antibody against this protein as a tool to investigate the virus-plant-vector relationship. The antibody reacted strongly with the homologous protein expressed in vitro by ELISA, but poorly with the native protein present in leaf lesion extracts from sweet orange caused by CiLV-C. Reactions from old lesions were more intense than those from young lesions. Western blot and in situ immunolocalization assays failed to detect the native protein. These results suggest low expression of the movement protein (MP) in host tissues. Moreover, it is possible that the conformation of the protein expressed in vitro and used to produce the antibody differs from that of the native MP, hindering a full recognition of the latter.

A generalization of the Moore-Penrose inverse related to matrix subspaces of C(nxm)

[EN]A natural generalization of the classical Moore-Penrose inverse is presented. The so-called S-Moore-Penrose inverse of a m x n complex matrix A, denoted by As, is defined for any linear subspace S of the matrix vector space Cnxm. The S-Moore-Penrose inverse As is characterized using either the singular value decomposition or (for the nonsingular square case) the orthogonal complements with respect to the Frobenius inner product. These results are applied to the preconditioning of linear systems based on Frobenius norm minimization and to the linearly constrained linear least squares problem.

Rivera, Luis Fernando: "Antropología existenciaria; el hombre como centro y sentido" Bs. As., Guadalupe, 1983.

Fil: Yerga de Ysaguirre, M. C.. Universidad Nacional de Cuyo. Facultad de Filosofía y Letras. Instituto de Filosofía Argentina y Americana

Metales pesados como indicador de impacto de un sistema ecológico fragmentado por usos de suelo, San Luis Potosí, México

La necesidad de estudiar la presencia de metales pesados en el suelo radica en su impacto como indicador de contaminación ambiental. Se determinó la presencia de Cu, Zn, Pb y Cd en suelos donde se distribuyen especies vegetales en un corredor ecológico. Entre los municipios de Soledad de Graciano Sánchez y San Luis Potosí (México) fueron establecidos 30 puntos distribuidos en cinco prácticas dominantes de usos de suelo: agropecuario, residencial rural, comercio y servicios, residencial urbano y minero. Los muestreos se realizaron en cuatro épocas durante 2009 y 2010 (verano, otoño, invierno y primavera). Se encontró un efecto significativo del uso del suelo en cuanto a los niveles de Cu (p = 0,000), Pb (p = 0,043) y Cd (p = 0,010). En el caso del Zn, el uso del suelo (p = 0,000) y la estación (p = 0,059) fueron significativos. El uso del suelo minero mostró las mayores concentraciones de metales y el agrícola las menores. Los niveles de los cuatro metales se encuentran en el rango marcado como alto por la EPA y por otras fuentes técnicas. En el caso de Pb y Cd no rebasan los estándares NOM-147- SEMARNAT-SSA1. Estos resultados reflejan el potencial indicativo del uso del suelo en la evaluación de la calidad ambiental, sin embargo, se requiere continuar con un monitoreo de metales pesados en la zona.

Alejandro Korn. Lecciones de Historia de la Filosofía c. 1918. Transcripción y primera edición por Clara Alicia Jalif de Bertranou. Introducción por Juan Carlos Torchia Estrada. Mendoza, Argentina, Universidad Nacional de Cuyo, Facultad de Filosofía y Letras, Instituto de Filosofía Argentina y Americana– IFFA, 2011, 412 p.

Fil: Manzo Guaquil, Luis. Universidad de Valparaíso

La presencia de Cansinos Assens en las letras de Jorge Luis Borges

Rafael Cansinos Assens, figura determinante en el nacimiento del "ismo" español en épocas de vanguardias europeas, el ultraísmo, y Jorge Luis Borges, introductor de los principios del movimiento en la Argentina, traban amistad en el año 1920, cuando este último comienza a participar en las tertulias organizadas por el escritor sevillano en el Café Colonial de Madrid. Y dicha relación se intenta recuperar, en este trabajo, no como mención a los escritores en un plano eminentemente biográfico, sino como integrante de la producción escrita de Jorge Luis Borges en la década del 20 del siglo pasado. En este sentido se destacan, entre otros, algunos textos borgeanos como "Ultraísmo" de 1921, "La traducción de un incidente", "Definición de Cansinos Assens" y "A Rafael Cansinos Assens" de 1924, "Las luminarias de Hanukah" de 1926 y "R. Cansinos Assens" de 1927.

Polémicas por la detención de Pinochet : El caso de Jorge Edwards y Luis Sepúlveda

El artículo se sitúa ante las polémicas suscitadas entre escritores chilenos y españoles a raíz de la detención de Augusto Pinochet en octubre de 1998. LIntenta mostrar cómo las posiciones que encarnaron entonces los escritores chilenos Jorge Edwards y Luis Sepúlveda, sobre todo a través de la polémica que sostuvieron desde las páginas del diario madrileño El País, sirvieron de referentes básicos en la toma de posturas ante el «episodio de Londres¼. Se reavivóLa detención de Pinochet obligó a un debate urgente sobre los pactos de transición chilenos y el estado de la memoria histórica reciente del país. Sepúlveda encauzó el sentir de aquellos que no terminaban de suscribíanir los acuerdos oficiales de la transicióntransición, por juzgarlos «amnésicos¼ conrespecto a la memoria de las víctimas de la dictadura. Edwards, por su parte, encarnó la postura de quienes preferían posponer a otras etapas de la transición los juicios históricos adel periodo de la dictadura, en aras de la consolidación de la paz social. Mientras la postura de Sepúlveda reunió a la mayoríapractica totalidad de escritores e intelectuales, la de Edwards resumió una opinión más extendida entre políticos y analistas hispanoamericanos. A propósito de la invocación de Edwards a una Ilustración política pendiente en Latinoamérica, en este artículo se incluye en responde a una línea de investigadoración más dilatada en torno a la presencial significado deado a la Ilustración hispanoamericana en las narraciones históricas deque sobre este periodo se han hecho en las últimas décadas. En este sentido, se analiza la polémica en un contexto amplio, al considerar los referentes históricos a que recurrieron ambos autores.

Las "autobiografías" de Luis Cernuda

Las dos compilaciones de poemas en prosa de Luis Cernuda, así como su texto Historial de un libro presentan algunas características autobiográficas que implican diversas variantes respecto del canon del género. Se analiza en especial Variaciones sobre un tema mexicano, su estructura y temporalidad, las consideraciones histórico-literarias que el texto contiene y el esfuerzo del autor por crear una imagen idealizada de México, en cuyo centro significante, aunque no representado, se destaca la figuración del lenguaje coloquial mexicano.