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Search Results: 1 - 10 of 599690 matches for " Marco A. Obregón-Mendoza "
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Facile Preparation of 1,2-Diols from Chalcones: An NMR Spectroscopy and X-Ray Crystallography Study  [PDF]
Marco A. Obregón-Mendoza, María Miriam Estévez-Carmona, Carolina Escobedo-Martínez, Manuel Soriano-García, Raúl G. Enríquez
International Journal of Organic Chemistry (IJOC) , 2015, DOI: 10.4236/ijoc.2015.53015
Abstract: Structures of 2-(naphthalen-2-ylmethyl)-2,3-dihydro-1H-indene-1,2-diol (C20H18O2), compound 1 and 1-(3,4-dimethoxyphenyl)-3-methoxy-3-(4-nitrophenyl)propane-1,2-diol chloroform (C18H21NO7·CHCl3) compound 2 were established by spectral and X-ray diffraction studies. Compound 1 crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 5.2177 (6), b = 13.903 (2), c = 21.121 (2) A, Z = 4. Compound 2 crystallizes in the triclinic space group P-1 with unit cell parameters a = 9.238 (1), b = 9.879 (1), c = 12.636 (1) A, α = 102.004 (1), β = 92.356 (1), γ = 90.779 (1)o, Z = 2. These two new molecules arise from a facile preparation of 1,2-diols from chalcones and have been fully characterized. Based on the crystallographic information obtained for compound 1, the relative configuration for the chiral centers is 1S and 2S. In structure 1, both hydroxyl groups adopt an anti-conformation with a torsion angle O1-C1-C2-O2 value of 93.1 (2)o [in molecule 2, both hydroxyl groups adopt a trans-conformation with a torsion angle O1-C1-C2-O2 value of 171.0 (2)]. In both structures, the molecules in the crystal are linked by intermolecular hydrogen bonds O-H···O and C-H···O interactions and adjacent molecules are interconnected by intermolecular weak C-H···π and C-H···Cl interactions which give additional support to molecular packing stability.
Crystal Structure, Synthesis and Biological Activity of Ether and Ester Trans-Ferulic Acid Derivatives  [PDF]
Marco A. Obregón-Mendoza, M. Mirian Estévez-Carmona, Yair Alvarez-Ricardo, William Meza-Morales, Carolina Escobedo-Martínez, Manuel Soriano-García, Raúl G. Enríquez
International Journal of Organic Chemistry (IJOC) , 2018, DOI: 10.4236/ijoc.2018.84028
Abstract: The structures of methoxymethyl (E)-3-(4-hydroxy-3-methoxyphenyl)acrylate, 2; (E)-3-(3-methoxy-4-(methoxymethoxy)phenyl)acrylic acid, 3; methyl (E)- 3-(4-(benzyloxy)-3-methoxyphenyl)acrylate, 4; benzyl (E)-3-(4-(benzyloxy)- 3-methoxyphenyl)acrylate, 6; and (E)-3-(4-(benzyloxy)-3-methoxyphenyl)- acrylic acid, 7; were established by spectroscopic and X-ray diffraction studies. Structure 2 is a new com-pound. Compounds with free phenolic hydroxyls v.gr. methyl (E)-3-(4-hydroxy-3-methoxyphenyl)acrylate 1, 2 and ben-zyl(E)-3-(4-hydroxy-3-methoxyphenyl)acrylate 5, showed scavenging free- radical and antioxidant activity while moderate scavenging free-radical was observed in compound 3. Moderate inhibition of lipid peroxidation was observed for 7. Compound 5 exerted significant inhibition of cell growth in PC-3, K562 tumor cell lines and 4 exhibited the largest cytotoxic effect upon the K562 cell line.
Medical-scientific knowledge raising in Cartagena de indias
Chajín-Mendoza Osiris María
Revista Ciencias Biomédicas , 2011,
Abstract: The importance of tracing the origins of acertain discipline in past practices that serve asits inheritance does not come simply from an interest in history. The importance lies inthat, in revising its origin, it is possible to discover that this wasn’t simple, but markedby contradictions. Medical practice isn’t stranger to such situations. In Cartagena, thedevelopment of medical knowledge is linked to significant concerns about urban life,such as public health, social assistance and the recognition of the medical profession,among other topics that are redefined by the force of imaginaries of the progress withthe passage of the 19th century to the 20th century. The aim of this paper is to surveythe rise of the scientific medical knowledge in Cartagena, from a corpus of researchconcerned with the subject, in the context of the historical evolution of the city.RESUMEN:La importancia de rastrear los orígenes de un determinado saber en las prácticas pasadasque le sirven de herencia, no proviene simplemente de un interés por la historia. Laimportancia radica en que, al revisar su origen, es posible descubrir que éste no fuesimple, sino que estuvo signado por contradicciones. La práctica médica no es ajena aeste tipo de situaciones. En Cartagena, el desarrollo del saber médico se vincula conpreocupaciones significativas de la vida urbana, como la higiene pública, la asistenciasocial y el reconocimiento del oficio médico, entre otros temas que se resignifican por lafuerza de los imaginarios del progreso propio del paso del siglo XIX al siglo XX. Nuestroobjetivo en este artículo es revisar el ascenso del saber médico científico cartagenero, através de un corpus de investigaciones preocupadas por el tema en el marco del devenirhistórico de la ciudad.
Photoluminescence Response of HfO2:Eu3+ Obtained by Hydrothermal Route  [PDF]
Elizabeth Navarro Cerón, Geonel Rodríguez Gattorno, Jose Guzmán-Mendoza, Manuel García-Hipólito, Ciro Falcony
Open Journal of Synthesis Theory and Applications (OJSTA) , 2013, DOI: 10.4236/ojsta.2013.22009
Abstract:

In this work, the synthesis and photoluminescence response of HfO2 doped with Eu3+ (HfO2:Eu3+) are reported. The synthesis was carried out by the hydrothermal route of HfCl4 and EuCl.6H2O with NH4OH dissolved in deionized water. To perform the hydrolysis, the precursors were subjected to hydrothermal treatment at 120°C, under autogenously pressure at reaction times of 24, 40, 52 and 72 hours. The synthesized nanoparticles were characterized by mean of X- ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), and energy dispersive spectroscopy (EDS). Samples excited with 395 nm radiation show photoluminescence emission lines corresponding to the electronic transitions 5D0

The institution of medical education in Cartagena From the look of Horacio zabaleta Jaspe
Chajín-Mendoza Osiris María,Monterrosa-Castro álvaro
Revista Ciencias Biomédicas , 2012,
Abstract: It was in October 1976, the year of final closure of the almost century-old Santa ClaraUniversity Hospital, where a doctor and professor at the Faculty of Medicine, Universityof Cartagena, Colombia, Horacio Zabaleta Jaspe gave birth a book, which has becomea classic and required document to uncover the history of medicine, doctors and localmedical education. Taking this hospital as the nucleus and calling to mind the feeling, thememory, to witness and document text wove a simple style and narrative. Embroideryon the edge of events, presents in detail the history of medical education in Cartagena,with a detailed account of its history, origins and development. The book fondly called,Requiem for an old hospital, on the starts and the becoming’s of medical education in Cartagena, from the beginning to the seventies of the twentieth century. Are extractedfrom its pages and discuss between the lines, the process of institutionalization ofmedical training and the rise of health care, from the chief physician to the formal figure of the professor.RESUMEN:Fue en octubre de 1976, a o del cierre definitivo del casi centenario HospitalUniversitario de Santa Clara, cuando el médico y profesor de la Facultad de Medicinade la Universidad de Cartagena, Colombia, Horacio Zabaleta Jaspe dio a la luz unlibro, que se ha convertido en clásico y obligado documento para develar la historiade la medicina, de los médicos y de la ense anza médica local. Tomando como núcleodicho hospital y apelando a la memoria, al sentimiento, al recuerdo, al testimonio yal documento, tejió un texto con estilo sencillo y narrativo. Bordado a la orilla de loseventos, presenta al detalle la historia de la ense anza de la medicina en Cartagena,haciendo un relato pormenorizado de sus antecedentes, orígenes y desarrollo. El librodenominado con nostalgia, Réquiem por un viejo hospital, presenta los inicios y losdevenires de la ense anza de la medicina en Cartagena, desde los albores hasta ladécada de los setenta del siglo XX. Se extraen de sus páginas y se comentan entrelíneas, el proceso de la institucionalización de la formación médica y el surgimientodel profesional médico, desde el protomédico a la figura formal del catedrático.
Variación espacial y temporal de la diversidad de hormigas en el Jardín Botánico del valle de Zapotitlán de las Salinas, Puebla
Guzmán-Mendoza, Rafael;Casta?o-Meneses, Gabriela;Herrera-Fuentes, María del Carmen;
Revista mexicana de biodiversidad , 2010,
Abstract: the knowledge about ants of arid zones of mexico is very poor. for this reason we assessed the biodiversity of this taxon in 2 sites with different vegetation structure. ten pitfall traps were placed in each site, and 2 surveys were conducted, 1 in august (rainy season, 2004) and another in february (dry season, 2005). the capture was more abundant in the rainy season; however, during the study, a higher ant diversity was observed in the site with low vegetation cover and few plant diversity. compared with other arid zones of mexico, the zapotitlán de las salinas valley is the site with the highest ant species richness. the new records have increased richness to 27 ant species, which is very close to the number of species registered in other localities near zapotitlan. our data suggest that increasing sampling effort and application of different sampling techniques, the ant richness species could be increased.
Variación espacial y temporal de la diversidad de hormigas en el Jardín Botánico del valle de Zapotitlán de las Salinas, Puebla Spatial and temporal variation of the diversity ants in the Botanic Garden from Zapotitlán de las Salinas Valley, Puebla
Rafael Guzmán-Mendoza,Gabriela Casta?o-Meneses,María del Carmen Herrera-Fuentes
Revista mexicana de biodiversidad , 2010,
Abstract: Debido al escaso conocimiento que se tiene de las hormigas de las zonas áridas de México, se evaluó la biodiversidad de este taxón en el Jardín Botánico de Zapotitlán de las Salinas, Puebla. Se realizaron 2 colectas, una en época de lluvias (agosto de 2004) y otra en la temporada de secas (febrero de 2005). En ambas ocasiones se seleccionaron 2 sitios contrastantes en estructura vegetal y se colocaron 10 trampas de caída para cada sitio. La captura fue más abundante en temporada de lluvias. El sitio con menor diversidad y cobertura vegetal mostró una mayor diversidad de hormigas durante el estudio. Comparado con otras zonas áridas de México, el valle de Zapotitlán de las Salinas resultó ser una de las zonas semiáridas con mayor riqueza en especies de hormigas; con 12 nuevos registros se incrementó a 27 el número de especies, sólo una por debajo de otras localidades cercanas al valle. Los datos sugieren que con un mayor esfuerzo de muestreo y la aplicación combinada de otras técnicas de recolección, la riqueza de especies en el área podría elevarse considerablemente. The knowledge about ants of arid zones of Mexico is very poor. For this reason we assessed the biodiversity of this taxon in 2 sites with different vegetation structure. Ten pitfall traps were placed in each site, and 2 surveys were conducted, 1 in August (rainy season, 2004) and another in February (dry season, 2005). The capture was more abundant in the rainy season; however, during the study, a higher ant diversity was observed in the site with low vegetation cover and few plant diversity. Compared with other arid zones of Mexico, the Zapotitlán de las Salinas Valley is the site with the highest ant species richness. The new records have increased richness to 27 ant species, which is very close to the number of species registered in other localities near Zapotitlan. Our data suggest that increasing sampling effort and application of different sampling techniques, the ant richness species could be increased.
Respuesta a: Comentarios sobre el artículo "Evaluación de las técnicas de capacitación espermática y su efecto en la fragmentación del ADN" Answering to Comments on "Assesment of sperm capacitation techniques and their effect on DNA fragmentation"
Luisa Fernanda Calderón-Mendoza
Revista Colombiana de Obstetricia y Ginecología , 2012,
Abstract:
Apoptotic effect on HeLa Cells produced by Chlamydia trachomatis-LPS
Millán-Mendoza,Beatriz; Hakimi,Hamid; Eley,Adrian;
Kasmera , 2007,
Abstract: the interaction between the lipopolysaccharide (lps) of chlamydia trachomatis and mammalian cells is still largely unknown. chlamydia trachomatis is an obligate intracellular bacterium responsible for several diseases in humans and animals. in this work, thanks to the isolation of the lipopolysaccharide from two serovars of chlamydia trachomatis (lgv1-lgv2) and using a nuclear supravital fluorescent stain (hoechst 33258), it was possible to investigate the apoptotic effect on hela cells. this work shows the apoptotic effect on hela cells when they were exposed to c. trachomatis-lps from two serovars at concentrations equal to or higher than 0.5 μg/ml for a period of 48h. and also the lack of cellular response in the absence of c. trachomatis-lps or in the presence of lps obtained from other bacteria. additionally, the use in equal conditions of polymyxin b, known as an inhibitor of bacterial lps, showed a decrease of the apoptotic effect in such cells indicating that the cellular response observed was produced by c. trachomatis-lps. these results support the theory that the lps from c. trachomatis could be responsible for the toxic effect on cervical cells infected by these bacteria.
Adaptabilidad y estabilidad de 20 variedades de maíz, Panamá
Gordón-Mendoza,Román; Franco-Barrera,Jorge; Camargo-Buitrago,Ismael;
Agronomía Mesoamericana , 2010,
Abstract: adaptability and stability of 20 corn varieties in panama. the objective of this work was to determine the adaptability and stability of 20 corn varieties in panama. from sep tember 2007 to january 2008, uniform yield tests were evaluated in six locations with contrasting environments in panama. the genetic material consisted of nine qpm synthetics and eleven with normal grains, all from cimyt. the experimental design employed was complete randomized blocks with three replications. the experimental plots were two 5-m long rows with 0,75 m between rows. the combined analysis of variance showed statistically significant differences between the two groups (synthetic vs. normal) for yield and other economically and genetically important variables within groups. on the other hand, the interaction genotype x environment was significant for grain yield, indicating differential responses of the genotypes. the combined analysis of the mean yields showed that among the normal synthetics, sa-n6-07, sa-n8-07 and sa-n7- 07 exhibited outstanding yield with means higher than 4,0 t/ha, whereas within the qpm, sa-q14-07 and sa-q12-07 yielded 3,98 and 3,63 t/ha. the yield of a all these synthetics surpassed the normal grain control (guararé-8128) and the qpm control (sa-q5-06) which yielded 2.93 and 3.36 t/ha, respectively. the biplot gge-sreg model identified the synthetics sa-n6-07, sa-q14-07 and sa-n10-07 with the highest stability; additionally, the first two were the best yielding varieties within each group.
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