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Search Results: 1 - 10 of 435500 matches for " H. S. Luna "
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Influência da vitrifica o na incidência de ovócitos bovinos aneuplóides maturados in vitro.
H. S. Luna,I. Ferrari,R. Rumpf
Revista Brasileira de Saúde e Produ??o Animal , 2006,
Abstract: O presente estudo objetivou verificar a incidência de aneuploidias em ovócitos bovinos vitrificados em diferentes períodos de matura o. Os ovócitos foram obtidos de ovários de abatedouro e divididos em cinco grupos: controle (ovócitos n o vitrificados); grupos 0-h (vitrificados antes do come o da matura o); e grupos 8, 12 e 22-h (vitrificados respectivamente 8, 12 e 22 h após o come o da matura o). Os ovócitos permaneceram vitrificados por 24 h e ent o foram descongelados e completaram 24 horas de matura o. Em seguida os ovócitos foram desnudados, fixados em lamina e corados com orceína-acética. Nenhuma diferen a foi encontrado (P > 0,05) entre o grupo controle (6,2%, 1/16 ) e grupos 0, (22,0, 2/9) 8 h (22,0, 2/9), 12 (25,0%, 3/12), 22 h (23,5%, 4/17). Os resultados sugerem que a vitrifica o em diferentes períodos de matura o n o influencia na taxa de aneuploidia.
Spectroscopic binaries in the open cluster Trumpler 16 revisited
G. J. Luna,H. Levato,S. Malaroda,M. Grosso
Physics , 2003,
Abstract: We have recalculated the orbits of 3 binary systems, members of the open cluster Trumpler 16 in the Carina region. We have added new observations to those available in the literature. Also, we have also tried to find the orbital periods for two suspected binary systems in the same cluster. We have improved considerably the precision of some of the orbital parameters.
Developing an Advanced Prototype of the Acousto-Optical Radio-Wave Spectrometer for Studying Star Formation in the Milky Way  [PDF]
Alexandre S. Shcherbakov, Abraham Luna
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.41012
Abstract:

The designed practically prototype of an advanced acousto-optical radio-wave spectrometer is presented in a view of its application to investigating the Milky Way star formation problems. The potential areas for observations of the cold interstellar medium, wherein such a spectrometer can be exploited successfully at different approximations, are: 1) comparison of the Milky Way case with extragalactic ones at scale of the complete galactic disk; 2) global studies of the Galactic spiral arms; and 3) characterization of specific regions like molecular clouds or star clusters. These aspects allow us to suggest that similar instrument will be really useful. The developed prototype of spectrometer is able to realize multi-channel wideband parallel spectrum analysis of very-high-frequency radio-wave signals with an improved resolution power exceeding 103. It includes the 1D-acousto-optic wide-aperture cell as the input device for real-time scale data processing. Here, the current state of developing this acousto-optical spectrometer in frames of the astrophysical instrumentation is briefly discussed, and the data obtained experimentally with a tellurium dioxide crystalline acousto-optical cell are presented. Then, we describe a new technique for more precise spectrum analysis within an algorithm of the collinear wave heterodyning. It implies a two-stage integrated processing, namely, the wave heterodyning of a signal in an acoustically square-law nonlinear medium and then the optical processing in the same solid-state cell. Technical advantage of this approach lies in providing a direct multi-channel parallel processing of ultra-high-frequency radio-wave signals with the resolution power exceeding 104. This algorithm can be realized on a basis of exploiting a large-aperture effective acousto-optical cell, which operates in the Bragg regime and performs the ultra-high-frequency co-directional collinear acoustic wave heterodyning. The general concept and basic conclusions here are confirmed by proof-of-principle experiments with the specially designed cell of a new type based on a lead molybdate crystal.

Multibody effects in intermolecular interactions and reaction pathways for catalytic processes. Part II the contributions of Sidonio Castillo
Novaro, O.;Pacheco-Sánchez, J.H.;Luna, H.;
Revista mexicana de física , 2009,
Abstract: we here continue the review on the work of octavio novaro and collaborators in the important field of nonadditivity of intermolecular interactions and catalysis, with special interest in the work that sidonio castillo contributed to this effort before his demise. his early work with polish coauthors on methane and ammonia trimers and with british coauthors on n3, p3, n4 and p4 are highlighted. then our focus will shift mainly to his work on the activation of methane, silane and germane starting with his ph.d. thesis under o. novaro and ending in his last papers with the present authors which marked the end of his short but brilliant career.
Multibody effects in intermolecular interactions and reaction pathways for catalytic processes. Part II the contributions of Sidonio Castillo
O. Novaro,J.H. Pacheco-Sánchez,H. Luna
Revista mexicana de física , 2009,
Abstract: Aquí continuaremos la revisión del trabajo de Octavio Novaro y sus colaboradores en los importantes campos de la no aditividad de las interacciones intermoleculares y de la catálisis, enfatizando las contribuciones de Sidonio Castillo que resultaron altamente útiles en este esfuerzo conjunto, antes de su prematuro fallecimiento. Sus primeros trabajos, con reconocidos científico polacos en los trímeros de metano y amoniaco y con coautores ingleses en trimeros y tetrámeros de fósforo y nitrógeno, serán presentados primero, seguidos de sus estudios sobre la activación catalítica de moléculas de metáno, silano y germano (de alto potencial en aplicaciones valiosas). Sus primeros trabajos en catálisis formaron parte de su tesis doctoral dirigida por O. Novaro y los últimos fueronconsecuencia de las tesis doctorales que el Dr. Castillo dirigió a los otros dos coautores de esta revisión. Esta labor fue desgraciadamente interrumpida por la muerte de Sidonio. Así concluyó su corta pero brillante carrera.
Enzymatic Hydrolysis of N-protected 2-Hydroxymethylpiperidine Acetates
Solís, Aida;Nava, Artemio;Pérez, Herminia Inés;Manjarrez, Norberto;Luna, Héctor;Cassani, Julia;
Journal of the Mexican Chemical Society , 2008,
Abstract: liver acetone powders (laps) were used as hydrolase sources to biocatalyze the hydrolysis of n-protected-2-hydroxymethylpiperidine acetates (n-ts and n-boc). different reaction conditions were evaluated, like source of lap (cat, guinea pig, chicken, dog, sheep, bovine, rat, mouse, pig and rabbit), proportion of cosolvent, type of cosolvent and ph.
Producción de Dextrinas a partir de Almidón Nativo de Yuca por Ruta Seca en una Agroindustria Rural
Velasco,Reinaldo J; Luna,William A; Mera,Julián A; Villada,Héctor S;
Información tecnológica , 2008, DOI: 10.4067/S0718-07642008000200003
Abstract: in a rural agricultural industry, cassava variety mcol 1505 was used to obtain dextrin using a dry route developed in the laboratory and tested in a pilot plant. the optimum concentration of starch was 37.8 (w / v) and the final ph had an average of 3.1. the pre-drying process was conducted with air between 55 and 60 °c at a flowrate of 0.21 m3/s with a homogenization system, during 120 minutes for pellets of 3 to 5% moisture. for the conversion of cassava to dextrin an airflow of 0.1 m3/s at 150 °c and a homogenization system were used, being the conversion time of 45 minutes. cassava dextrin of quality similar to the commercial corn starch dextrin was obtained. it was found that experimental conditions determined in the laboratory continued to be valid at industrial level except for the mixing and drying operations.
Microbial biocatalytic preparation of 2-furoic acid by oxidation of 2-furfuryl alcohol and 2-furanaldehyde with Nocardia corallina
HI Pérez, N Manjarrez, A Solís, H Luna, MA Ramírez, J Cassani
African Journal of Biotechnology , 2009,
Abstract: The preparation of 2-furoic acid via oxidation of 2-furfuryl alcohol and 2-furanaldehyde was studied by two procedures using whole cells of Nocardia corallina B-276. We describe a comparison using a batch cultivation (3-L) versus resting cells in potassium phosphate buffer (0.1 M, pH 7.0). In the 3-L bioreactor, 2-furfuryl alcohol (1.35 g/L) was biotransformed after 24 h, to the acid with 81% yield. The bioconversion of 2-furfuryl alcohol using resting cells leads to and almost quantitative yield (98%) of 2-furoic acid in 21 h. 2-furanaldehyde was also oxidized to the 2-furoic acid in 88% yield in 8 h, the ratio substrate:cells was 1:3.5 (w/w). This method was scaled up to 9 g/L of 2-furanaldehyde.
Hydrogen Fuel Cell Design and Manufacturing Process Used for Public Transportation in Mexico City
G. Luna-Sandoval,G. Urriolagoitia-C,L.H. Hernandez,G. Urriolagoitia-S
Lecture Notes in Engineering and Computer Science , 2011,
Abstract:
Screening of Liver Acetone Powders in the Enantioselective Hydrolysis of Naproxen Esters
Ana Pacheco,Héctor Luna,Aida Solís,Herminia I. Pérez
Revista de la Sociedad Química de México , 2006,
Abstract: Polvos acetónicos de hígado de diferentes fuentes fueron aplicados a la hidrólisis de los ésteres metílico y butílico del naproxén. Los resultados muestran que es difícil hacer generalizaciones respecto a las condiciones de reacción, ya que estas dependen significativamente de la fuente del LAP y del sustrato. Por ejemplo, en la hidrólisis del naproxenato de metilo por el LAP de conejo la conversión fue del 20% con un ee en el ácido producido del 44% a pH 8, en contraste a un 80% de ee a pH 7.5 con el LAP de pollo a la misma conversión. El LAP de gato dio una conversión del 80% en todos los pHs con un 90% de ee a pH 7.5. Los resultados para la hidrólisis del naproxenato de butílo fueron diferentes; con el LAP de puerco la conversión fue del 40%, pero solo dio 43% ee, el LAP de guajolote dio solo 12% de conversión y un 90% de ee y el LAP de gato dio 17% de conversión y 90% de ee, todos estos resultados a un pH de 7.5. Todos los LAPs probados, a excepción del de borrego, mostraron una preferencia hacia la hidrólisis del enantiómero R.
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