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Search Results: 1 - 10 of 410633 matches for " Laura M. Machuca "
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N-Acetylated Gemini Surfactants: Synthesis, Surface-Active Properties, Antifungal Activity, and Ecotoxicity Bioassays  [PDF]
Laura M. Machuca, Ulises Reno, Silvana C. Plem, Ana María Gagneten, Marcelo C. Murguía
Advances in Chemical Engineering and Science (ACES) , 2015, DOI: 10.4236/aces.2015.52023
Abstract: A series of N-acetylated cationic gemini surfactants (3a-e) having dimeric structures derived from tertiary amines were synthesized. Their antifungal potency and surface properties were determined. It also studied the acute toxicity of the molecule with the best performance and the best water solubility (3e) through Chlorella vulgaris and Daphnia magna bioassays. The results were compared to those obtained for a commercially available reference compound 2-(thiocyanomethylthio) benzothiazole (TCMTB). Parameters such as surface tension (ϒCMC), critical micelle concentration (CMC), surface excess concentration (Γ), and area per molecule (A) were determined. The resulting values indicated that the five gemini surfactants are characterized by good surface-active and self-aggregation properties. All surfactants were tested to evaluate their antifungal activity. Six fungal strains were used to conduct the study. The minimum inhibitory concentration (MIC) value was measured by the fungal growth inhibition. The results of the MICs were compared with two commercially available reference compounds (Fluconazole and TCMTB). The least active molecule was 3e, but 3b and 3d were found to be the most potent compounds with a similar activity for all strains. Candida albicans was the most sensitive one. In contrast, Aspergillus niger was resistant. Ecotoxicity of gemini 3e was assessed: the commercial formulation (TCMTB) was between three and four orders of magnitude more toxic than the gemini one for the biological species tested.
Production and Sensory Evaluation of Novel Cheeses Made with Prebiotic Substances: Inulin and Oligofructose  [PDF]
Laura M. Machuca, Yamila E. Rodriguez, Daniela E. Guastavino Meneguini, María E. Bruzzo, María F. Acu?a Ojeda, Marcelo C. Murguía
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.616153
Abstract: In recent years, the processing and consumption of functional foods worldwide have greatly increased. These foods benefit the body functions which improve consumers’ health and also reduce the risk factors that cause the onset of disease. Furthermore, prebiotic substances favor the multiplication of beneficial intestinal bacteria rather than harmful ones. The purpose of this study was to conduct the sensory evaluation of two functional cheeses containing inulin and oligofructose as a distinctive ingredient, including testing a cheese made with conventional ingredients, called control cheese. Affective type tests, which measured the degree of liking or disliking, were conducted using a verbal 7-point hedonic scale. According to the inclusion and exclusion criteria, 57 untrained judges were selected. This study is a quantitative, analytic and experimental-cross design. Statistical analysis of the data was performed by ANOVA with repeated measures. The results show a similar average degree of liking for the three cheeses, above 5 on the scale or “like”. By analyzing the critical level and the result of the Mauchly’s sphericity test, it is concluded that there is no statistically significant difference in the degree of liking for the three cheeses. Therefore, the addition of prebiotics to artisanal cheeses achieves to satisfy consumers and provide them benefits superior to those provided by traditional foods.
Los hacendados y rancheros mayas de Yucatán en el siglo XIX
Machuca Gallegos, Laura;
Estudios de cultura maya , 2010,
Abstract: haciendas were not exclusive for "white" powerful groups, since they were available for the maya. hacienda was one of the only productive economic activities in the peninsula, so the maya (in spite of being a minority) became the owners. they even had debtor workers. they were not marginalized from economic development but rather participated actively in it. this paper studies maya masters by following some of their strategies and reconstructing both their binds and relations. our main source are notarial documents, particularly testaments, where some variables like spouse, testamentary executor and witness are studied.
Rese a de "De colonial a nacional: la carrera eclesiástica del clero secular chileno entre 1650 y 1810" de Lucrecia Raquel Enríquez Agrazar
Laura Machuca Gallegos
Fronteras de la Historia , 2010,
Abstract:
Diputados yucatecos y campechanos en Cádiz y su idea sobre la Península de Yucatán, 1810-1814
Machuca Gallegos, Laura
Anuario de Estudios Americanos , 2012,
Abstract: This article analyzes the role of the six deputies who were sent to Cadiz by the Province of Yucatan from 1810 to 1814. They had not a remarkable performance; so far from worrying about issues of general interest, theirs efforts were on promoting local issues considered of vital importance for them. Until 1810, Yucatán had played with an image using the poverty of the population and the distance from the centers of power, but from Cadiz this speech was changed for one of wealth and autonomy to be suited in the new times. En este artículo se analiza el papel de los seis diputados que fueron mandados a Cádiz por la Provincia de Yucatán entre 1810 y 1814. No tuvieron una actuación notable, pues, lejos de preocuparse por los problemas de interés general, destaca el empe o que pusieron en favorecer asuntos locales que sí se consideraban de vital importancia. Hasta 1810 Yucatán había jugado con la carta de la pobreza de los habitantes y la lejanía de los centros de poder, pero desde Cádiz este discurso fue cambiado por uno de opulencia y autonomía, pues así convenía presentarse en los nuevos tiempos.
Los hacendados y rancheros mayas de Yucatán en el siglo XIX Maya hacendados and rancheros from Yucatán in the 19th Century
Laura Machuca Gallegos
Estudios de cultura maya , 2010,
Abstract: No sólo los grupos "blancos" y pudientes de la sociedad tuvieron haciendas, sino también los mayas. Al ser la hacienda una de las pocas actividades económicas productivas que se podían llevar a cabo en la península, algunos mayas (si bien son minoría) se volvieron propietarios, incluso tuvieron trabajadores adeudados; por tanto, no permanecieron al margen del desarrollo económico y participaron activamente de éste. Así, en este trabajo nos ocupamos de los amos mayas, seguimos algunas de sus estrategias y reconstruimos sus lazos y sus relaciones. La principal fuente utilizada han sido documentos de carácter notarial, en particular los testamentos, de los cuales se han estudiado algunas variables como la de cónyuge, albacea testamentario y testigo. Haciendas were not exclusive for "white" powerful groups, since they were available for the Maya. Hacienda was one of the only productive economic activities in the peninsula, so the Maya (in spite of being a minority) became the owners. They even had debtor workers. They were not marginalized from economic development but rather participated actively in it. This paper studies Maya masters by following some of their strategies and reconstructing both their binds and relations. Our main source are notarial documents, particularly testaments, where some variables like spouse, testamentary executor and witness are studied.
Efecto de tipos de inóculos de tres especies fúngicas en la micorrización controlada de plántulas de Pinus radiata
Chávez M,Daniel; Pereira C,Guillermo; Machuca H,ángela;
Bosque (Valdivia) , 2009, DOI: 10.4067/S0717-92002009000100002
Abstract: in the present study different types of inoculum: sporal (si), solid micelial (smi), and liquid micelial (lmi) of ectomycorrhizal fungi were evaluated on the controlled mycorrhization of pinus radiata seedlings growing under experimental nursery conditions. the fungal species were rhizopogon luteolus, suillus bellinii and suillus luteus collected from pinus radiata plantations in the province of bíobío, in the viiith region of chile. the fungal species were cultivated on the solid medium mmn (modified melin-norkrans), ph 5.8, and incubated for 30 days to produce the sources of micelial inoculum under liquid (lmi) and solid (smi) conditions. to obtain the si the carpophores collected in field were cleaned (previous identification in the laboratory) and then crushed in blender (1000 rpm) containing desionized water. the different types of inoculum were kept in glass bottles, at 4° c in darkness, until their use. the results indicated that the effect of the type of inoculum changed according to the fungal species studied. the best results after eleven months for the plant mycorrhization were observed when smi and lmi obtained from r. luteolus and lmi from s. luteus were used. the species s. bellinii did not present differences in the mycorrhization reached by the plants with the different types of inoculum. among three species of ectomycorrhizal fungi studied, r. luteolus showed the biggest effects on the growth of the p. radiata seedlings in nursery.
The Orton's hypothesis about hemispheric lateralization and reading-writing performance revisited: An ex post facto study in Spanish context
Machuca, M. y Fernández-Cano, A.
Revista Electrónica de Investigación y Evaluación Educativa , 2002,
Abstract: This paper attempts to inquiry the connections between hemispherical laterality and reading-writing performance, based on the theory that Samuel T. Orton established over 60 years ago. No evidence has been found to show a significant correlation between both constructs. Therefore, the widely held belief that the one depends on the other can be refuted.
Producción de hidrocarburos líquidos y gaseosos mediante la colicuefacción térmica del carbón mineral con residuos de polietileno de baja densidad
Fiderman Machuca,Juan M. Barraza,Alberto Bola?os
El Hombre y la Máquina , 2007,
Abstract: En este trabajo, un carbón sub bituminoso de la mina La Yolanda (Valle del Cauca), se colicuó térmicamente con residuos de polietileno de baja densidad (LDPE), en presencia de tetralina e hidrógeno. Se usó un reactor batch de 115 ml y agitación magnética, temperaturas de 380, 400 y 420°C, relaciones de masa carbón/polietileno/tetralina 1/5/3 y tiempo de residencia de 30 minutos. Los resultados muestran que para la colicuefacción térmica en presencia de tetralina, la conversión total y la distribución de productos fueron una función de la temperatura de reacción; la conversión decrece mientras que los aceites, asfaltenos, preasfaltenos y la selectividad se incrementan con la temperatura. Los resultados también muestran que elevadas conversiones y concentración de asfaltenos fueron obtenidas a 400°C utilizando una mezcla de carbón polietileno únicamente. En estas condiciones, la selectividad hacia aceites usualmente fue más baja que el 20%.
Efecto de tipos de inóculos de tres especies fúngicas en la micorrización controlada de plántulas de Pinus radiata Effect of inoculum type of three fungal species on the controlled mycorrhization of Pinus radiata seedlings
Daniel Chávez M,Guillermo Pereira C,ángela Machuca H
Bosque (Valdivia) , 2009,
Abstract: En el presente estudio se evaluó la incidencia de diferentes tipos de inóculos (esporal IE, miceliar sólido IMS y miceliar líquido IML) de hongos ectomicorrícicos en la micorrización controlada de plántulas de Pinus radiata en condiciones experimentales de invernadero. Las especies fúngicas utilizadas fueron Rhizopogon luteolus, Suillus bellinii y Suillus luteus, recolectadas de plantaciones de P. radiata, en la provincia de Bíobío, VIII Región, Chile. Las especies aisladas fueron cultivadas en medio de cultivo sólido MNM (Melin-Norkrans Modificado), pH 5,8, e incubadas durante 30 días para producir las fuentes de inóculos miceliares en condiciones líquidas (IML) y sólidas (IMS). Para obtener el IE se limpiaron los carpóforos recolectados en terreno (previa identificación en laboratorio) y luego se trituraron en una licuadora (1.000 rpm) con agua desionizada. Los diferentes tipos de inóculo fueron mantenidos en recipientes de vidrio, a 4° C en oscuridad, hasta su utilización. Los resultados obtenidos después de once meses indicaron que el efecto del tipo de inóculo varió según la especie fúngica. Para la especie R. luteolus, los mejores resultados de la micorrización de plantas fueron obtenidos con IMS e IML; en cambio, para S. luteus fue el IML. La especie S. bellinii no presentó diferencias en la micorrización alcanzada por las plantas con los diferentes tipos de inóculos aplicados. De las tres especies de hongos ectomicorrícicos estudiados, con R. luteolus fueron alcanzados los mayores efectos en el crecimiento de las plantas de P. radiata en vivero. In the present study different types of inoculum: sporal (SI), solid micelial (SMI), and liquid micelial (LMI) of ectomycorrhizal fungi were evaluated on the controlled mycorrhization of Pinus radiata seedlings growing under experimental nursery conditions. The fungal species were Rhizopogon luteolus, Suillus bellinii and Suillus luteus collected from Pinus radiata plantations in the province of Bíobío, in the VIIIth Region of Chile. The fungal species were cultivated on the solid medium MMN (modified Melin-Norkrans), pH 5.8, and incubated for 30 days to produce the sources of micelial inoculum under liquid (LMI) and solid (SMI) conditions. To obtain the SI the carpophores collected in field were cleaned (previous identification in the laboratory) and then crushed in blender (1000 rpm) containing desionized water. The different types of inoculum were kept in glass bottles, at 4° C in darkness, until their use. The results indicated that the effect of the type of inoculum changed according to the fungal s
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