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Search Results: 1 - 10 of 71199 matches for " Daniel Hernández Medina "
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Two agronomical aspects of Tagetes terniflora HBK for essential oil production  [PDF]
Miguel ángel Serrato Cruz, Francisco Díaz Cedillo, Daniel Hernández Medina, Arturo Curiel Rodríguez
Journal of Agricultural Chemistry and Environment (JACEN) , 2014, DOI: 10.4236/jacen.2014.31002
Abstract: The genus Tagetes is a possible source of essential oils for the biorational control of pests and diseases in Mexico. The aim of the present study was to assess the distance between plants (PD; 15 × 80, 30 × 80 and 60 × 80 cm) and urea fertilization (0, 60 and 120 kg·he-1 N) for biomass production and essential oil in Tagetes terniflora HBK. Oil was obtained by the aerial part hydro-distillation and its chemical composition was analyzed by gas chromatography coupled to mass spectrometry. Factors N, PD and their interaction did not change plant height or the number of branches per plant; however, PD factor modified fresh tissue (FW) and dry tissue (DW) weights and the amount of oil per plant (p ≤ 0.05) which represent a good biomass production (30 to 72.5 ton·he-1 FW, 11 to 27 ton·he-1 DW) and oil producing (168 to 383 L·he-1 ) potential in the field. Urea did not have effect on both biomass and oil response per plant but interaction of 15 x 80 DP and 120 N could favor higher biomass and oil production potential (78 ton FW, 28 ton·he-1 DW and 608 L·he-1 , respectively). Essential oil yield varied from 0.3 to 2.1% according to the management conditions. A total of 11 major compounds were identified in essential oil, the relative quantity was constant in different agronomic management factors: E- tagetone (22%), cistagetenone (20.4%), transtagetenone (20.4%), dihydrotagetone (13.4%) and cis-β-ocimene (10.3%), trans-β-ocimene (5.0%), propenyl anisole (4.3%), sphatulenole (1.1%), allyl anisole (0.7%), Z-tagetone (0.5%) and limonene (0.5%).
Molecular Modeling of Potential Dual Inhibitors of HIV Reverse Transcriptase and Integrase  [PDF]
Alberto Cabrera, Leonor Huerta Hernández, Daniel Chávez, José L. Medina-Franco
Computational Molecular Bioscience (CMB) , 2018, DOI: 10.4236/cmb.2018.81001
Abstract: With the goal of suggesting dual inhibitors of HIV reverse transcriptase (RT) and integrase (IN), herein we report the molecular docking of an initial set of 556 compounds related to the pyridinone class. Docking with multiple crystallographic structures of HIV-1 RT led to 160 potential binders of RT interacting with key amino acid residues at the enzyme’s allosteric site. Compounds selected from the docking with RT were further docked with a crystallographic structure of HIV-1 IN. A total of 31 structures had the potential to make contacts with Mg2+ ions located in a small space between DNA and IN. Interactions with Mg2+ ions are relevant because they participate in the stabilization of the IN-DNA complex. In conclusion, 31 compounds synthetically accessible are proposed as dual inhibitors of RT and IN. It is hypothesized that the suggested compounds will inhibit RT by occupying the allosteric site for NNRTIs and will inhibit the catalytic activity of IN by destabilizing the IN-DNA complex. The main perspective of this work is the synthesis and biological testing of the candidate molecules.
Molecular Modeling of Quinoline-Based Compounds as Potential Dual Inhibitors of Reverse Transcriptase and Integrase of HIV  [PDF]
Alberto Cabrera, Leonor Huerta Hernández, Daniel Chávez, José L. Medina-Franco
Computational Molecular Bioscience (CMB) , 2018, DOI: 10.4236/cmb.2018.83007
Abstract: As follow-up of our past publication[1], we propose that quinolones (as part of the pyridinone family) are capable to increase the number of interactions with HIV reverse transcriptase (RT) or integrase (IN) by adding a halogen in position C-8 of aromatic portion of the quinolones. This addition could help with the activity of dual inhibitors of RT and IN. In this work, we add a chlorine atom with the rationale to identify in the docking simulations a halogen interaction with the oxygen in the near aminoacids in the binding pockets of RT and IN enzymes. Our docking studies started with RT and 320 structures. Later, we took 73 structures with good results in docking with RT. The structures that we choose contain ester or acids groups in C-3 due the structural similarity with groups in charge to interact with the Mg++ ions in Elvitegravir. In conclusion, we obtained 14 structures that could occupy the allosteric pocket of RT and could inhibit the catalytic activity of IN, for this reason could be dual inhibitors. A major perspective of this work is the synthesis and testing of the potential dual inhibitors designed.
Utilidad de la biopsia estereotáctica en lesiones del tallo cerebral
HERNáNDEZ SALAZAR, MANUEL;LORENZANA GALICIA, RODRIGO DANIEL;RAMíREZ CASTA?EDA, VICENTE;ZáRATE MéNDEZ, ANTONIO;CERVERA MALTOS, ULISES;CEVALLOS MEDINA, JAVIER;
Archivos de neurociencias (México, D.F.) , 2004,
Abstract: the stereotactic biopsy has been recently developed from 80's for brainstem lesions, and is one of the most update and promising fields of medicine, despite of its potential complication, however most of the trials has shown its reliance and accuracy. patients and methods: from 85 consecutive stereotactic biopsies, 11 were made for brainstem lesions (13%) stereotactically. diagnostics were obtained by preoperative mr and ct which confirmed the brainstem lesions. it was made a frequency chart with age, gender, location and extension of the lesion, imagenologic and clinic features, as well as complementary treatments and survival time. an excel chart was made with all data and was submitted to descriptive and inferential statistical methods. results: fatal outcome in a period less than 6 months was in 45.5% (n=5), more than 6 months 54.5% (n=6), nevertheless the survival time in all the cases was 7.7 months ±6.8, we have to clear up that in 80% (n=9) of the cases in this study the survival time was 11 months. conclusions: the complications rates exists but the benefit is justified due to illness severity with a confirmed diagnostic. a stereotactic approach to the brainstem lesions can provide a field of positive histological diagnosis with a low mortality.
LA SOLARIZACIóN DEL SUELO EN EL MARCO DE LA CONSERVACIóN DEL MEDIO AMBIENTE
CARLOS HERNáNDEZ MEDINA
Lámpsakos , 2010,
Abstract: Se conceptualiza en la solarización del suelo como método de Manejo Integrado de Plagas y Enfermedades que afectan a las plantas cultivadas. Se definen los factores que influyen sobre la efectividad de la solarización en la desinfección del suelo. Se explican los procesos por los cuales los patógenos son inactivados al solarizar el suelo. El empleo de la solarización posibilita el uso combinado de técnicas de control que utilicen métodos biológicos y culturales con un mínimo trabajo de control químico. Su combinación nos permite evitar el uso de fumigantes como el Bromuro de Metilo y Vapam de conocida toxicidad y efecto esterilizante sobre el agroecosistema.
Infecciones del sistema nervioso central por enterovirus en ni?os atendidos en un hospital de Lima, Perú
Espinoza,Iván O; Ochoa,Theresa J; Mosquito,Susan; Barletta,Francesca; Hernández,Roger; Medina,María del Pilar; Stiglich,María Luisa; Ugarte,Claudia; Guillén,Daniel;
Revista Peruana de Medicina Experimental y Salud Pública , 2011, DOI: 10.1590/S1726-46342011000400005
Abstract: objectives. to determine the frequency and clinical features of central nervous system infections caused by enterovirus in children treated at the hospital nacional cayetano heredia in lima, peru. materials and methods. a prospective, descriptive study was performed from april 2008 to march 2010. patients aged 1 month - 14 years with clinical diagnosis of encephalitis or aseptic meningitis were included. we investigated the presence of enterovirus, herpes simplex virus 1 (hsv-1), herpes simplex virus 2 (hsv-2) and varicella-zoster virus (vzv) by polymerase chain reaction (pcr). results. 97 patients were included, out of which 69 % had acute encephalitis and 31 % acute meningitis. enteroviruses were identified in 52,6% of all acute non-bacterial central nervous system infections; corresponding to 83,3 % of meningitis and 38,8 % of encephalitis. there were no cases of infection due to hsv-1, hsv-2 or vzv. enterovirus infections reached 82,9 % in the warm months (november-january) and 28,6 % in the colder months (may-july). conclusions. enteroviruses are the principal etiologic agents in acute aseptic meningitis and encephalitis in pediatric patients in lima, peru. enteroviruses have a seasonal epidemiological pattern with a clear increase in the number of cases during the summer months. it is useful to have this rapid diagnostic method available as an aid in the management of acute central nervous system infections.
The night and day of dung beetles (Coleoptera, Scarabaeidae) in the Serra do Japi, Brazil: elytra colour related to daily activity
Hernández, Malva Isabel Medina;
Revista Brasileira de Entomologia , 2002, DOI: 10.1590/S0085-56262002000400015
Abstract: in the present study 387 dung beetles (coleoptera: scarabaeidae) were surveyed at the serra do japi, in the atlantic forest in s?o paulo state, with four baited pitfall traps during the months of december, 1998, and january, 1999 during eight 24 hour cycles. a total of 30 species were identified and temporal variation in activity patterns among the species shows a specialization in the use of food resources: 9 species were classified as nocturnal and 13 as diurnal. the daily activity pattern of dung beetles does not necessarily correspond to the taxonomic classification, but is strongly related to the colouring of species, determined by predominant elytra colour: nocturnal species have 89 % more chances of being black as opposed to colourful. black nocturnal species might have evolved as an interspecific adaptation to avoid predation (cryptic colouring). among the colourful diurnal dung beetles, measure of body length of each species shows that development of bright colouring was more often found in medium to large species, which suggests that colouring evolved as a response to intraspecific pressures, important in agonistic encounters among males.
Los estudios sobre comunicación masiva en América Latina
Lic. Ileana Medina Hernández
Revista Latina de Comunicación Social , 1998,
Abstract: En el continente latinoamericano, primero colonizado, luego neocolonizado y siempre subdesarrollado, muchas veces las tendencias culturales y académicas han sido eco de las metrópolis europeas y norteamericanas. La investigación en comunicaciones no ha estado exenta de ello.
Cuba, Canarias y la prensa, en el contexto del 98
Lic. Ileana Medina Hernández
Revista Latina de Comunicación Social , 1998,
Abstract: 1898 es para Espa a el a o del Desastre, con mayúscula; 1898 es para Cuba el a o de la independencia, quizá con minúscula. Canarias es la puerta de salida de Europa; Cuba es puerta la entrada de América. La migración canario - cubana ha sido un factor histórico decisivo en la formación de ambas nacionalidades. La prensa de masas naciente a fines del siglo XIX jugó un papel determinante en la guerra hispano-norteamericana y su desenlace. Conjugando esas cuatro sentencias aplastantes y archiconocidas, la investigación del reflejo del proceso independentista cubano en la prensa de canaria aporta sustanciosos elementos al conocimiento del papel de los procesos de comunicación en la historia y en la cultura de ambos archipiélagos, en el importante contexto del fin de siglo XIX.
Los grupos étnicos y los sistemas tradicionales de poder en México
Andrés Medina Hernández
Nueva antropología , 1983,
Abstract:
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