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Search Results: 1 - 10 of 328183 matches for " F Ruiz-Terán "
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Antioxidant and free radical scavenging activities of plant extracts used in traditional medicine in Mexico
F Ruiz-Terán, A Medrano-Martínez, A Navarro-Oca a
African Journal of Biotechnology , 2008,
Abstract: Twenty-two species of medicinal plants collected in the Mexican state of Morelos were selected to evaluate their free radical scavenging and antioxidant activities. The extracts from the aerial parts of the plants were obtained using hexane, acetone and methanol (66 extracts). The initial qualitative screening of antioxidants was made using two TLC methods against the stable DPPH (1,1-diphenyl-2- picrylhydrazyl-hydrate) and -carotene-linoleic acid bleaching assay. All the extracts displayed antioxidant activity. However, the methanol extracts appeared to have the highest antioxidant activity, so they were examined further. The quantitative assays against DPPH radical, -carotene-linoleic acid bleaching and total amount of phenols in the methanol extracts (TPME) showed nine plants as having the highest scavenging and antioxidant activities. For the nine methanolic extracts analysed, a clear relation between the total phenolic content of the extracts and their antioxidant activity was found. Plants such as Annona squamosa and Sapium macrocarpum showed two times more antioxidant activity than the commercial BHA (butylated hydroxyanisole) antioxidant. Moreover, some methanolic extracts of the plants showed activities comparable to commercial antioxidants BHA and TBHQ (tertbutylhydroquinone), thus making it possible to consider some of the studied plants as a potential source of antioxidants of natural origin.
Las interpretaciones del simbolo ?X? en los polinomios
Quintero,Roy; Ruiz,Deyse; Terán,Ruperto;
Educere , 2006,
Abstract: this article has the analysis of research results that set out to investigate the many interpretations that both professors and students give the symbol ?x?, which is used in scholarly environments to represent the concepts of ?variable ?, ?indeterminate? and ?unknown? within the polynomial unit in eight grade of primary education. the same symbol represents diferent mathematical objects, that is, ?x? is used to represent the indeterminate in the ?polynomial definition ?; the unknown in a ?polynomial equation ? and the variable in a ?polynomic function ?. to achieve this, the methodological approach used was ethnography.
Helicobacter Pylori: Enteropatógeno frecuente del ser humano
Rivera,M; Contreras,F; Terán,A;
Archivos Venezolanos de Farmacología y Terapéutica , 2004,
Abstract: this paper reviews current knowledge in relation to the bacterial infection caused by helicobacter pylori, frequently associated to gastrointestinal diseases, and direct cause of peptic ulcer disease. besides this, it is recognized as a carcinogenic agent, given its association with gastric carcinoma. helicobacter pylori, is a gram negative bacillus that colonizes gastric mucosa, with a worldwide distribution, and it?s highly detected in patients with gastrointestinal symptoms, therefore its physiology and different morphologies that exert an effect over its pathogenicity are described, among the physiopathologic mechanisms underlying clinical presentations, endoscopic methods and biochemistry tests specific for diagnosis and finally treatment.
What is thermodynamics and what is it for?
tern,Gyula Gróf
Interdisciplinary Description of Complex Systems , 2012,
Abstract: Thermodynamics – contrary to its name – is not a dynamic theory. However, some relatively new developments, like finite time, endo-reversible or ordinary thermodynamics introduce time into thermostatics. In this framework the Second Law becomes a set of conditions ensuring the asymptotic stability of equilibrium. In this manuscript some examples are shown, how this basic conceptual change can lead to a profound understanding.
Helicobacter Pylori: Enteropatógeno frecuente del ser humano
M Rivera,F Contreras,A Terán
Archivos Venezolanos de Farmacología y Terapéutica , 2004,
Abstract: En este artículo se revisan los conceptos recientes en relación a una infección bacteriana cuyo agente causal es Helicobacter Pylori, frecuentemente implicado en cuadros gastrointestinales diversos y responsable directo de la enfermedad úlcero-péptica que además es reconocido como agente carcinógeno tipo I por su asociación con cáncer gástrico. Helicobacter Pylori es un bacilo gram negativo que coloniza la mucosa gástrica de amplia distribución mundial, presentes con una alta frecuencia en pacientes que consultan con sintomatología gastrointestinal, por lo que se analizan aspectos básicos de su fisiología, sus diferentes morfologías que directamente van a repercutir en su patogenicidad y se detallan los mecanismos fisiopatológicos responsables de los diferentes cuadros clínicos, los métodos endoscópicos y de laboratorio específicos para el diagnóstico y los avances más recientes en el tratamiento y profilaxis de la enfermedad. This paper reviews current knowledge in relation to the bacterial infection caused by Helicobacter pylori, frequently associated to gastrointestinal diseases, and direct cause of peptic ulcer disease. Besides this, it is recognized as a carcinogenic agent, given its association with gastric carcinoma. Helicobacter pylori, is a gram negative bacillus that colonizes gastric mucosa, with a worldwide distribution, and it’s highly detected in patients with gastrointestinal symptoms, therefore its physiology and different morphologies that exert an effect over its pathogenicity are described, among the physiopathologic mechanisms underlying clinical presentations, endoscopic methods and biochemistry tests specific for diagnosis and finally treatment.
Complicaciones Macrovasculares en Diabetes Tipo 2 Asociación con Factores de Riesgo
F Contreras,N Barreto,S Jiménez,L Terán
Archivos Venezolanos de Farmacología y Terapéutica , 2000,
Abstract: Con el objeto de determinar la incidencia de complicaciones macrovasculares en sujetos diabéticos tipo 2 en la ciudad de los Teques, se seleccionaron 40 pacientes que acuden a la consulta de diabetes del HVSR entre Febrero y Noviembre de 1998, con diagnóstico de diabetes tipo 2 y 30 pacientes con características semejantes, sanas. Se dise o un estudio de tipo descriptivo transversal. A tal fin se realizó historia clínica detallada que incluía la presencia de factores de riesgo cardiovascular (HTA, dislipemias, hábito tabáquico, consumo de alcohol, tratamiento dietético y/o farmacológico). Seguidamente se determinaron parámetros antropométricos, perfil lipídico, glicemia basal y hemoglobina glicosilada. Entre los principales resultados cabe se alar diferencias significativas entre el grupo experimental y el grupo control en cuanto a IMC; relación C/C, glicemia en ayunas y hemoglobina glicosilada. En el grupo experimental, además, destacan: edad 48±8.05 a os (x±DE) siendo su distribución por sexo del 45% varones y 55% mujeres. El tiempo de evolución de la diabetes desde su diagnóstico fue de 10,4 ± 8,3 a os. Se evidenció un consumo de alcohol de 15% en total y 10% de hábito tabáquico. El valor promedio, de glicemia basal 160,40±40,6 mg/dL con HbA1c de 7,4±1,2%. La hipertensión arterial estuvo presente en 60% de los pacientes. 70% presentaban dislipemia según los criterios de la Asociación Venezolana de Aterosclerosis (SVA). El IMC resultó elevado en 78% de los casos con un rango de 31,4±4,2. Se detectó hiperfibrinogenemia de 380±50 mg/dL; el 35,4% de los pacientes presentaba complicaciones macrovasculares al momento de su evaluación siendo la más frecuente la enfermedad vascular periférica en 25% de los casos. Todos estos resultados enfatizan la necesidad de realizar un enfoque integral del paciente diabético que permita no solo un control adecuado de la glicemia sino también un correcto tratamiento de los principales factores de riesgo asociados a complicaciones macrovasculares. In order to determine the incidence of gross vascular complications in adults with Diabetes Mellitus Type 2, was designed a descriptive transversal study. We selected 40 patients with diagnosis of Diabetes Mellitus type 2, attending the Outpatient Diabetic Clinic at the Victorino Santaella Ruiz Hospital in Los Teques, Venezuela and 30 healthy subjects with similar characteristics as group control, from February to November 1998. The patient’s age ranged from 30 to 75 years, all with more than five years since their first diagnosis of Diabetes Type 2 and complying with the inclusio
Ventrículo único. Estudio con ecocardiografía transtorácica. Single ventricle transthoracic echocardiography study.
José Abreu Cruz,Ana M. álvarez Ruiz,Saúl Armenteros Terán,Rogelio Romero Millares
Revista Cubana de Cardiología y Cirugía Cardiovascular , 1997,
Abstract: El ventrículo único ocurre en 1 x 6 500 nacimientos, asociándose a la transposición de grandes vasos y en la estenosis pulmonar, entre otros. El cuadro clínico dependerá de la anomalía coexistente. Mediante ecocardiografía 2-D (desde aproximación apical), se muestra imagenológicamente la ausencia de tabique interventricular y cámara rudimentaria en un varón de 38 a os, cianótico desde el nacimiento. Se confirma a través del angiocateterismo la existencia de un ventrículo común. The single ventricle occurs in 1 x 6 500 births. It is associated with the transposition of great vessels and also with lung stenosis, among others. The clinical picture depends on the coexistent anomaly. Echocardiography 2-D (from apical approximation) was used to show the absence of intraventricular septum and rudimentary chamber in a 38 year old man, who was cyanotic since birth. The single ventricle is confirmed by angiocatheterism.
Primer registro de Kunsia tomentosus (Rodentia: Cricetidae: Sigmodontinae) en el norte del departamento de La Paz, Bolivia
Terán,Marcos F.; Ayala,Jhonny; Hurtado,Juan C.;
Mastozoolog?-a neotropical , 2008,
Abstract: bolivia is a country with great biodiversity. it still holds areas that shelter a faunistic diversity that is poorly known. an example of this is province abel iturralde in departamento la paz. this region includes a variety of ecosystems including amazonian savannah fragments in an area called pampas del heath. in this site was captured the sigmodontine rodent kunsia tomentosus, species known only from the eastern part of bolivia. this report of k. tomentosus extends the species distribution in the continent, raising interesting questions on the biogeography of the species.
EFFICIENCY AND COST MODELLING OF THERMAL POWER PLANTS
ter Bihari,Gyula Gróf,Iván Gács
Thermal Science , 2010, DOI: tsci1003821b
Abstract: The proper characterization of energy suppliers is one of the most important components in the modelling of the supply/demand relations of the electricity market. Power generation capacity i. e. power plants constitute the supply side of the relation in the electricity market. The supply of power stations develops as the power stations attempt to achieve the greatest profit possible with the given prices and other limitations. The cost of operation and the cost of load increment are thus the most important characteristics of their behaviour on the market. In most electricity market models, however, it is not taken into account that the efficiency of a power station also depends on the level of the load, on the type and age of the power plant, and on environmental considerations. The trade in electricity on the free market cannot rely on models where these essential parameters are omitted. Such an incomplete model could lead to a situation where a particular power station would be run either only at its full capacity or else be entirely deactivated depending on the prices prevailing on the free market. The reality is rather that the marginal cost of power generation might also be described by a function using the efficiency function. The derived marginal cost function gives the supply curve of the power station. The load level dependent efficiency function can be used not only for market modelling, but also for determining the pollutant and CO2 emissions of the power station, as well as shedding light on the conditions for successfully entering the market. Based on the measurement data our paper presents mathematical models that might be used for the determination of the load dependent efficiency functions of coal, oil, or gas fuelled power stations (steam turbine, gas turbine, combined cycle) and IC engine based combined heat and power stations. These efficiency functions could also contribute to modelling market conditions and determining the environmental impact of power stations.
PRIMER REGISTRO DE Kunsia tomentosus (RODENTIA: CRICETIDAE: SIGMODONTINAE) EN EL NORTE DEL DEPARTAMENTO DE LA PAZ, BOLIVIA
Marcos F. Terán,Jhonny Ayala,Juan C. Hurtado
Mastozoolog?-a neotropical , 2008,
Abstract: Bolivia es un país megadiverso con una lista de 356 especies de mamíferos. A pesar de esto todavía existen áreas con poco conocimiento de la diversidad faunística. La provincia Abel Iturralde del departamento de La Paz alberga una variedad de ecosistemas que incluyen fragmentos de sabanas amazónicas como las denominadas Pampas del Heath. En esta región se capturó al raro sigmodontino Kunsia tomentosus, especie sólo conocida para el este del país. Este registro es el primer reporte de K. tomentosus en esta parte de Bolivia ampliando la distribución de esta especie en el continente.
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