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Search Results: 1 - 10 of 221098 matches for " Luis G. Mendoza Luna "
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Nucleation, solvation and boiling of helium excimer clusters
Luis G. Mendoza Luna,Nagham M. Siltagh,Mark J. Watkins,Nelly Bonifaci,Frederic Aitken,Klaus von Haeften
Physics , 2015,
Abstract: Helium excimers generated by a corona discharge were investigated in the gas and normal liquid phases of helium as a function of temperature and pressure between 3.8 and 5.0 K and 0.2 and 5.6 bar. Intense fluorescence in the visible region showed the rotationally resolved $d^3\Sigma_u^+ \rightarrow b^3\Pi_g$ transition of He$_2^*$. With increasing pressure, the rotational lines merged into single features. The observed pressure dependence of linewidths, shapes and lineshifts established phases of coexistence and separation of excimer-helium mixtures, providing detailed insight into nucleation, solvation and boiling of He$_2^*$-He$_n$ clusters.
Probing the structure and dynamics of molecular clusters using rotational wavepackets
Gediminas Galinis,Cephise Cacho,Richard T. Chapman,Andrew M. Ellis,Marius Lewerenz,Luis G. Mendoza Luna,Russell S. Minns,Mirjana Mladenovic,Arnaud Rouzée,Emma Springate,I. C. Edmond Turcu,Mark J. Watkins,Klaus von Haeften
Physics , 2014, DOI: 10.1103/PhysRevLett.113.043004
Abstract: The chemical and physical properties of molecular clusters can heavily depend on their size, which makes them very attractive for the design of new materials with tailored properties. Deriving the structure and dynamics of clusters is therefore of major interest in science. Weakly bound clusters can be studied using conventional spectroscopic techniques, but the number of lines observed is often too small for a comprehensive structural analysis. Impulsive alignment generates rotational wavepackets, which provides simultaneous information on structure and dynamics, as has been demonstrated successfully for isolated molecules. Here, we apply this technique for the firsttime to clusters comprising of a molecule and a single helium atom. By forcing the population of high rotational levels in intense laser fields we demonstrate the generation of rich rotational line spectra for this system, establishing the highly delocalised structure and the coherence of rotational wavepacket propagation. Our findings enable studies of clusters of different sizes and complexity as well as incipient superfluidity effects using wavepacket methods.
La electroterapia: una alternativa terapéutica para el tratamiento de tumores
Bergues Cabrales,Luis; Gómez Luna,Liliana;
Revista Cubana de Medicina , 2003,
Abstract: electrotherapy is the therapy with low intensity direct electric current. it is used in medicine as a therapeutic alternative to treat tumors, its cost is low and its adverse effects are minimum. in different in vitro and in vivo studies, it has been showed the marked antitumoral effect of the direct electric current. the complete regression (or cure) of tumors is achieved in many cases. the direct electric current potentiates the antineoplastic action of radiotherapy and chemotherapy, and reduces the side effects that they induce in the organism. the most important results obtained in the treatment of tumors, its antineoplastic and side effects, as well as its possible mechanisms of action have been summarized in this bibliographic review.
La electroterapia: una alternativa terapéutica para el tratamiento de tumores
Luis Bergues Cabrales,Liliana Gómez Luna
Revista Cubana de Medicina , 2003,
Abstract: La electroterapia es la terapia con corriente eléctrica directa de baja intensidad. Se utiliza en medicina como alternativa terapéutica para tratar tumores, es de bajo costo y mínimos efectos adversos. En diferentes estudios in vitro e in vivo se ha demostrado el marcado efecto antitumoral de la corriente eléctrica directa, en muchos casos se obtiene la regresión (o cura) completa de los tumores. La corriente eléctrica directa potencia la acción antineoplásica de la radioterapia y quimioterapia, minimiza los efectos colaterales que éstas inducen en el organismo. En esta revisión bibliográfica sobre la corriente eléctrica directa se han resumido los resultados más importantes obtenidos en el tratamiento de tumores, sus efectos antineoplásicos y colaterales, así como sus posibles mecanismos de acción. Electrotherapy is the therapy with low intensity direct electric current. It is used in medicine as a therapeutic alternative to treat tumors, its cost is low and its adverse effects are minimum. In different in vitro and in vivo studies, it has been showed the marked antitumoral effect of the direct electric current. The complete regression (or cure) of tumors is achieved in many cases. The direct electric current potentiates the antineoplastic action of radiotherapy and chemotherapy, and reduces the side effects that they induce in the organism. The most important results obtained in the treatment of tumors, its antineoplastic and side effects, as well as its possible mechanisms of action have been summarized in this bibliographic review.
Time evolution of decay of two identical quantum particles
Gastón García-Calderón,Luis Guillermo Mendoza-Luna
Physics , 2011, DOI: 10.1103/PhysRevA.84.032106
Abstract: An analytical solution for the time evolution of decay of two identical non interacting quantum particles seated initially within a potential of finite range is derived using the formalism of resonant states. It is shown that the wave function, and hence also the survival and nonescape probabilities, for factorized symmetric and entangled symmetric/antisymmetric initial states evolve in a distinctive form along the exponentially decaying and nonexponential regimes. Our findings show the influence of the Pauli exclusion principle on decay. We exemplify our results by solving exactly the s-wave delta shell potential model.
Chaotic Classical Scattering and Dynamics in Oscillating 1-D Potential Wells
G. A. Luna-Acosta,G. Orellana-Rivadeneyra,A. Mendoza-Galvan,C. Jung
Physics , 2001, DOI: 10.1016/S0960-0779(99)00184-8
Abstract: We study the motion of a classical particle interacting with one, two, and finally an infinite chain of 1D square wells with oscillating depth. For a single well we find complicated scattering behavior even though there is no topological chaos due to the absence of hyperbolic periodic orbits. In contrast, for two coupled square wells there is chaotic scattering. The infinite oscillating chain yields the generic transition to chaos, with diffusion in energy and in space, as the separation between wells is increased. We briefly discuss the relevance of our results to solid state physics.
Culture Mixed-Sex and Monosex of Tilapia in Ponds in Mexico City  [PDF]
Jose Luis Gómez-Márquez, Bertha Pe?a-Mendoza, María del Carmen Alejo-Plata, José Luis Guzmán-Santiago
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.62017
Abstract: In this study, the growth of Oreochromis niloticus both mixed sex and males sexually reversed were analyzed in concrete ponds in the FES Zaragoza, UNAM, under the environmental conditions of the Mexico City. The experiment was carried from May to November 2013, in two concrete ponds of 50 m2. Similar feeding regime and stocking density of fish were maintained for the culture systems. Different growth parameters like body weight, length, daily weight gain (DWG), specific growth rate (SGR), feed conversion rate (FCR), Fulton’s condition index (K) and survival were analyzed during six months culture period. It was found that culture with monosex males tilapias yielded the highest weight, length, DWG and SGR compared to mixed sex populations tilapias. Water quality was monitored along the experiment. Based on the results, there were statistically significant differences in size (W = 20942.5, p < 0.05) and weight (W = 21413.0, p < 0.05) between the divisions of the pond. The initial total length used was 1.2 cm and ended with 20.4 cm for monosex males, higher than mixed-sex population. The initial average body weight of the fish was 0.21 g and they recorded 192.2 g at the end of culture for monosex males. The weight-length relationship for both populations of fish was positive allometric. The percentage gain in body weight and total length averaged were 150% and 31.8% respectively. Specific growth rates in weight and length for monosex males were higher than mixed-sex population. Daily weight gain and size was similar in both populations. The FCR had a mean value of 1.9:1 for monosex males and condition factor (K) had an average of 1.45 for mixed-sex population. Water quality indicated good oxygenation (>5 mg/L), warm water (>20°C), productive (<100 mg/L CaCO3) and slightly basic (pH > 8). Acceptable growth of fish and a yield of 3 ton/ha/6 months were obtained in both two ponds; therefore, the culture of tilapia under conditions of Mexico City was recommended.
Non-Painful Peripheral Inflammation Blocks Conditioned Place-Preference to Morphine and Nicotine through an Ibuprofen-Sensitive and an Ibuprofen Insensitive Pathway  [PDF]
Marco Antonio Sotomayor-Sobrino, Abraham Ochoa-Aguilar, Eda Patricia Tenorio, Martha León-Olea, Roberto Velasco-González, Israel Luna-Mendoza, Claudia Gómez-Acevedo
Journal of Behavioral and Brain Science (JBBS) , 2018, DOI: 10.4236/jbbs.2018.82004
Abstract: The field of neuroimmunology has expanded in recent years providing new insights and therapies into pathologies like stroke, autism, and depression. However, few works explore the relationship between inflammatory stimuli and motivation. Thus, the aim of this study was to determine how non-painful inflammatory stimuli affect reward. To test reward-response, we used the morphine and the nicotine induced conditioned place-preference and place-aversion model in rats with non-painful inflammation. The following inflammatory models were used: non-painful infectious inflammation: 24 hrs prior to conditioning sessions, an injection with Calmette-Guerin bacillus (CGB) 1 × 107 cfu, ip, was administered. Non-painful non-infectious inflammation: 24 hrs prior to conditioning sessions, rats’ sciatic nerve was blocked and cut, followed by the injection of carrageenan (750 μl) in the paw. We then measured the cytokine concentration to determine the inflammatory profile of each of our models. Finally, we administered ibuprofen to determine if it could prevent the effect of inflammation over conditioned place-preference. We show that carrageenan significantly reduced the morphine-induced reward. Non-painful inflammatory stimulus, CGB and denervation + carrageenan, inhibit the conditioned place-preference to morphine and nicotine, CGB also block conditioned place-aversion to nicotine; carrageenan has no effect on CPA. The administration of ibuprofen reinstates conditioned place-preference to morphine and nicotine in the carrageenan model, but has no effect in the CGB model; finally ibuprofen has no effect on CPA. Our data suggest that non-painful-inflammatory stimuli inhibit the reward system, independent of cytokine concentration. Furthermore, the administration of a PGE 2 inhibitor can importantly modulate this phenomenon.
Hijo de madre adolescente: riesgos, morbilidad y mortalidad neonatal
Luis Alfonso Mendoza T,Martha Arias G,Laura Isabel Mendoza T
Revista Chilena de Obstetricia y Ginecología , 2012,
Abstract: Antecedentes: El embarazo en adolescentes es un problema de salud pública por las consecuencias para el binomio madre-hijo. Objetivo: Determinar las características y riesgos en madres adolescentes y sus hijos (antropometría, condición de nacimiento y morbi-mortalidad), en comparación con un grupo de madres adultas control de 20-34 a os. Métodos: Estudio de cohorte prospectiva con 379 hijos de mujeres adolescentes y 928 adultas. Los datos fueron analizados empleando mediana, promedio y medidas de dispersión, pruebas t-test no pareado o Wilcoxon rank-sum (Prueba de Mann-Whitney), ANOVA o Kruskall-Wallis, Chi2 o Exacta de Fisher, riesgo relativo y riesgo atribuible a la exposición porcentual con sus intervalos de confianza de 95%. Resultados: Entre adolescentes hubo mayor número de madres solteras (25,6%), menor escolaridad y seguridad social en salud (25,9%) (p<0,05). En adolescentes tempranas hubo más casos de preeclampsia (26,3%) y trabajo de parto prematuro (10,5%). Entre madres adolescentes el 30,9% de los hijos fueron prematuros, y presentaron más patología cardiaca, infecciones bacterianas, sífilis congénita, labio y paladar hendido, y mayor mortalidad, cuando se compararon con hijos de madres adultas (p<0,05). Conclusiones: La maternidad en adolescentes conlleva mayores riesgos de salud para ellas y sus hijos, aumentando la morbilidad, mortalidad, con una perspectiva de exclusión social a lo largo de la vida, pues la mayoría son pobres, con poca educación y madres solteras y sin pareja. Background: Adolescent pregnancy is a public health problem because of the consequences for mother and child. Objective: To determine the characteristics and risks in adolescent mothers and their children's (anthropometry, birth status, morbidity and mortality) compared with a group of older mothers 20-34 years and control their children. Methods: Prospective cohort study with 379 children and 928 adult female adolescents. Data were analyzed using median, mean and dispersion measures, tests unpaired t-test or Wil-coxon rank-sum (Mann-Whitney test), ANOVA or Kruskal-Wallis, Chi2 or Fisher's exact, relative risk and attributable risk percentage exposure with confidence intervals of 95%. Results: Among adolescents there were more single mothers (25.6%), lower education and social health insurance (25.9%) (p<0.05). In early adolescents were more cases of preeclampsia (26.3%) and preterm labor (10.5%). Among teenage mothers, 30.9% of the children were premature, and had more heart disease, bacterial infections, syphilis, and congenital cleft lip and palate and higher mo
Falla cardiaca e hiperaldosteronismo primario: Presentación de un caso Heart failure and primary hyperaldosteronism: Case report
Juan M Camargo,Fernán del C Mendoza,Efraín A Gómez,Rubén D Luna
Revista Colombiana de Cardiología , 2012,
Abstract: La insuficiencia cardiaca es un síndrome asociado con alta morbilidad y mortalidad, principalmente debido a episodios de agudización o descompensación. La cardiopatía hipertensiva es una etiología de la insuficiencia cardiaca con alta prevalencia en el mundo. El hiperaldosteronismo primario es una causa de hipertensión con incidencia creciente, que, independiente de la hipertensión, puede desencadenar miocardiopatía con todas sus consecuencias. En este artículo se presenta el caso de un paciente de cincuenta a os con insuficiencia cardiaca agudizada con disfunción sistólica, asociada a hipertensión resistente y como patología de base un estado con hipersecreción de aldosterona (hiperaldosteronismo primario). Heart failure is a syndrome associated with high morbidity and mortality, mainly due to episodes of exacerbation or decompensation. Hypertensive heart disease is a cause of heart failure with a high prevalence in the world. Primary hyperaldosteronism is a cause of hypertension with increasing incidence, which, independent of hypertension, can lead to cardiomyopathy with all its consequences. This article presents the case of a fifty years old male patient with acute heart failure exacerbated with systolic dysfunction, associated with resistant hypertension and having as underlying pathology a condition of aldosterone hypersecretion (primary hyperaldosteronism).
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