oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 190 )

2018 ( 330 )

2017 ( 339 )

2016 ( 534 )

Custom range...

Search Results: 1 - 10 of 197983 matches for " N. Nagles "
All listed articles are free for downloading (OA Articles)
Page 1 /197983
Display every page Item
LIQUID CULTURE FOR ISOLATING MICROORGANISMS WITH POTENTIAL TO DEGRADE METHYL PARATHION FROM AGRICULTURAL SOILS AND ORGANIC WASTE CULTIVO LíQUIDO PARA AISLAR MICROORGANISMOS CON POTENCIAL PARA DEGRADAR METIL PARATIóN A PARTIR DE SUELOS AGRíCOLAS Y RESIDUOS ORGáNICOS
L. R. Botero,N. Nagles,E. Barriuso,G. A. Pe?uela
Revista Ingenierías Universidad de Medellín , 2012,
Abstract: The search for microorganisms with high capacity for pesticide degradation is a very interesting attempt to approach bioremediation strategies in order to prevent contamination. This study evaluates the potential of agricultural soils and solid organic waste cultures microbial isolation as a strategy for screening microorganisms with potential for Methyl parathion (MP) degradation. For the study, microbial consortia were recovered from the liquid fraction of suspension cultures of agricultural soils and solid organic waste. Then, the MP degradation ability and its toxic effect on microbial activity were determined during microbial incubations under laboratory controlled conditions. The results showed that it is not possible to recover the active microorganisms that have potential to degrade the MP from the agricultural soils. However, an active consortium that would degrade both MP and its degradation products was isolated from the organic solid waste. La búsqueda de microorganismos con alta capacidad de degradación de los plaguicidas es un intento muy interesante de acercarse a las estrategias de biorremediación con el fin de evitar la contaminación. Este estudio evalúa el potencial del cultivo de microorganismos de suelos agrícolas y de residuos sólidos orgánicos como una estrategia para la detección de microorganismos con potencial para el metil paratión (MP) la degradación. Para el estudio, consorcios microbianos fueron recuperados de la fracción líquida de los cultivos en suspensión de los suelos agrícolas y los residuos sólidos orgánicos. La capacidad de degradación de la MP y su efecto tóxico sobre la actividad microbiana se determinó durante las incubaciones de los microorganismos en condiciones controladas de laboratorio. Los resultados mostraron que no es posible recuperar los microorganismos activos que tienen potencial para degradar el MP de los suelos agrícolas. Sin embargo, un consorcio activo que degradaría tanto MP y como sus productos de degradación se aisló a partir de los residuos sólidos orgánicos.
EFECTO DE LA CONCENTRACIóN DEL METIL PARATIóN Y EL EXTRACTO DE LEVADURA COMO FACTORES DE SELECCIóN DE MICROORGANISMOS DEGRADADORES DEL PESTICIDA A PARTIR DE SUELOS CONTAMINADOS Effect of Methyl Parathion Concentration and Yeast Extract as Factors for Selecting Pesticide Degrading Microorganisms from Polluted Soils
L. R. Botero,N. Nagles,J.C. Quintero,G. A. Pe?uela
Revista Ingenierías Universidad de Medellín , 2011,
Abstract: El aislamiento y cultivo de microorganismos con capacidades para degradar los contaminantes ambientales es importante para implementar planes de biorremediación. En este estudio se evaluó el efecto del extracto de levadura tanto en la capacidad de asimilación microbiana del pesticida organofosforado metil paratión, como en los procesos de aislamiento de microorganismos útiles para de degradar este pesticida. Los microorganismos evaluados fueron obtenidos de suelo fresco fumigado históricamente con este pesticida. Los ensayos se efectuaron con medios sólidos definidos enriquecidos con metil paratión (0-60 mg L-1) y extracto de levadura (0-0.5 g L -1). Se encontró que los microorganismos fueron capaces de asimilar hasta 5 mg L -1 del metil paratión en ausencia de extracto de levadura sin evidenciar efectos tóxicos. La capacidad de asimilación aumentó a 10 mg L-1 en los cultivos enriquecidos con 0.5 g L-1 de extracto de levadura. El extracto de levadura en las dosis usadas no afectó el aislamiento de microorganismos. Sin embargo, el aislamiento por siembra directa en medios enriquecidos con metil paratión como única fuente de carbono se dificultó por el aporte de la materia orgánica del suelo que permitió el crecimiento de cepas tolerantes sin capacidad para degradar el pesticida. Isolation and culture of microorganisms with capacity to degrade environmental pollutants are important for implementing bioremediation plans. This study is an evaluation of the yeast extract effect on both the microbial capacity to assimilate the organo-phosphorous pesticide methyl parathion and the isolation processes of microorganisms useful for degrading this pesticide. Microorganisms evaluated were obtained from fresh soil historically fumigate with this pesticide. Trials were conducted with defined solid means enriched with methyl parathion (0-60 mg L-1) and yeast extract (0-0.5 g L-1). It was found that microorganisms were able to assimilate up to 5 mg L-1 methyl parathion with no yeast extract, without evidence of toxic effects. Assimilation capacity increased 10 mg L-1 in cultures enriched with 0.5 mg L-1 yeast extract. Yeast extract in doses used did not affect the isolation of microorganisms. However, isolation through direct culture in means enriched with methyl parathion as the only source of carbon was difficult due to the addition of organic matter of soil, which allowed the growth of resistant strains with no pesticide degrading capacity.
Efectividad de la profilaxis para enfermedad tuberculosa en pacientes infectados por el virus de la inmunodeficiencia humana, Medellín, 2002-2005
Arbeláez,María Patricia; Arbeláez,Alexánder; Gómez,Rubén Darío; Rojas,Carlos; Vélez,Lázaro; Arias,Sonia Luz; Nagles,Jorge; Peláez,Luz Marina; Betancourt,Gloria; Velásquez,Gloria;
Biomédica , 2007,
Abstract: introduction. prophylaxis against tuberculosis has been recognized as important for preventing clinical forms of tuberculosis, mainly in hiv positive patients. however, in countries with high tuberculosis prevalence, prophylaxis application and effectiveness remains controversial. objective. effectiveness was established for two prophylaxis regimens -isoniazid treatment for nine months and pirazinamid/rifampin for 60 days. materials and methods. two cohort groups of patients diagnosed with hiv/aids were compared. one consisted of 131 volunteer patients, who received one of the two prophylactic regimens -pirazinamid/rifampin or isoniazid. the tuberculosis treatment drugs were self-administered and independent of tuberculin response tests. the second group consisted of 200 patients selected from the records of a hiv/aids control program. follow up for both groups was conducted over a two-year period through clinical records. results. the 2 groups were similar with respect to clinical and demographic variables. a higher proportion of patients in the control group had cd4 counts <200/ml and viral load >100,000 copies. in the prophylactic group, 8% of patients reported adverse effects due to the drug, and one person had tuberculosis in that group (0.8%). ten persons in the control group contracted tuberculosis (5%) rr=0.15, 95%ci 0.02-1.18, p=0.07. the prophylaxis protective level was calculated to be 80%, after taking into account cd4, viral load, and effective antiretroviral therapy. conclusion. the prophylaxis against tuberculosis was effective in hiv positive patients, independently of the immune status, viral load, and highly effective antiretroviral therapy.
DISE O DE UNA MAQUINA PRELIMPIADORA DE LABORATORIO DE ARROZ PADDY
OSCAR ARAQUE DE LOS RIOS,JOHAN ERICK NAGLES B.
Scientia Et Technica , 2009,
Abstract: La Empresa Molino Los Andes Ltda del sector arrocero, está interesada en el mejoramiento de su productividad preocupada por el porcentaje de impurezas en el momento de la recepción del producto, decide emprender un proyecto tendiente al mejoramiento de la estructura operativa del departamento de laboratorio lo cual redunda en los costos relacionados a la operación de pre limpiado. El documento propone el dise o de una maquina pre limpiadora de laboratorio que permita una extracción eficiente de impurezas en la etapa de recepción del producto. Inicialmente se caracterizan las variables físicomecánicas involucradas en el proceso, con base en esto se propone el dise o de un equipo que simule las condiciones particulares de la empresa y permita el control de las variables, finalmente se construye un prototipo experimental para determinar el porcentaje de impurezas en el proceso de pre limpiado de arroz paddy.
Frequency of CCR5 Delta-32 Mutation in Human Immunodeficiency Virus (HIV)-seropositive and HIV-exposed Seronegative Individuals and in General Population of Medellin, Colombia
Díaz, Francisco J;Vega, Jorge A;Pati?o, Pablo J;Bedoya, Gabriel;Nagles, Jorge;Villegas, Cecilia;Vesga, Rodrigo;Rugeles, Maria T;
Memórias do Instituto Oswaldo Cruz , 2000, DOI: 10.1590/S0074-02762000000200018
Abstract: repeated exposure to human immunodeficiency virus (hiv) does not always result in seroconversion. modifications in coreceptors for hiv entrance to target cells are one of the factors that block the infection. we studied the frequency of delta-32 mutation in ccr5 gene in medellin, colombia. two hundred and eighteen individuals distributed in three different groups were analyzed for delta-32 mutation in ccr5 gene by polymerase chain reaction (pcr): 29 hiv seropositive (sp), 39 exposed seronegative (esn) and 150 individuals as a general population sample (gps). the frequency of the delta-32 mutant allele was 3.8% for esn, 2.7% for gps and 1.7% for sp. only one homozygous mutant genotype (delta-32/delta-32) was found among the esn (2.6%). the heterozygous genotype (ccr5/delta-32) was found in eight gps (5.3%), in one sp (3.4%) and in one esn (2.6%). the differences in the allelic and genotypic frequencies among the three groups were not statistically significant. a comparison between the expected and the observed genotypic frequencies showed that these frequencies were significantly different for the esn group, which indirectly suggests a protective effect of the mutant genotype (delta-32/delta-32). since this mutant genotype explained the resistance of infection in only one of our esn persons, different mechanisms of protection must be playing a more important role in this population.
Implementation of a Higher Quality dc Power Converter  [PDF]
N. N. Barsoum
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.22012
Abstract: Many single and three-phase converters are well developed, and covered up in most of electric markets. It is used in many applications in power systems and machine drives. However, an exact definite output signal from the dc side still not recognized. The waveforms of output voltage and current demonstrate an imperfect dc signal and constitute losses, harmonic distortion, low power factor, and observed some ripples. An approximately perfect rectifier bridge is the aim of this research. Perhaps it gives the ability to identify the parameters of the converter to obtain, as much as possible, a perfect dc signal with less ripple, high power factor and high efficiency. Design is implemented by simulation on Power Simulator PSIM, and practically, a series regulator LM723 is applied to provide regulating output voltage. Comparisons of both simulation and hardware results are made to observe differences and similarities.
Estimation of Sensitivity of the DS/AHP Method While Solving Foresight Problems with Incomplete Data  [PDF]
N. Pankratova, N. Nedashkovskaya
Intelligent Control and Automation (ICA) , 2013, DOI: 10.4236/ica.2013.41011
Abstract:

The paper provides mathematical analysis of sensitivity of different combination rules in the DS/AHP method when an alternative is added to the set of decision alternatives while solving foresight problems. Different cases of rank reversals are defined and two sets of conditions for these cases using the method DS/AHP are considered. Rank reversals are illustrated when the DS/AHP method is used to solve practical problem of critical technologies of energy conservation and power efficiency evaluation in Ukraine. It is shown that the DS/AHP method is not sensitive to exclusion (or addition) of an irrelevant decision alternative from (or to) the set of decision alternatives.

Computation of the Genetic Code: Full Version  [PDF]
N. N. Kozlov
Journal of Computer and Communications (JCC) , 2017, DOI: 10.4236/jcc.2017.510008
Abstract: One of the problems in the development of mathematical theory of the genetic code (summary is presented in [1], the detailed—to [2]) is the problem of the calculation of the genetic code. Similar problem in the world is unknown and could be delivered only in the 21st century. One approach to solving this problem is devoted to this work. For the first time a detailed description of the method of calculation of the genetic code was provided, the idea of which was first published earlier [3]), and the choice of one of the most important sets for the calculation was based on an article [4]. Such a set of amino acid corresponds to a complete set of representation of the plurality of overlapping triple gene belonging to the same DNA strand. A separate issue was the initial point, triggering an iterative search process all codes submitted by the initial data. Mathematical analysis has shown that the said set contains some ambiguities, which have been founded because of our proposed compressed representation of the set. As a result, the developed method of calculation was reduced to two main stages of research, where at the first stage only single-valued domains were used in the calculations. The proposed approach made it possible to significantly reduce the amount of computation at each step in this complex discrete structure.
The Study of the Secrets of the Genetic Code  [PDF]
N. N Kozlov
Journal of Computer and Communications (JCC) , 2018, DOI: 10.4236/jcc.2018.67007
Abstract: The disclosure of many secrets of the genetic code was facilitated by the fact that it was carried out on the basis of mathematical analysis of experimental data: the diversity of genes, their structures and genetic codes. New properties of the genetic code are presented and its most important integral characteristics are established. Two groups of such characteristics were distinguished. The first group refers to the integral characteristics for the areas of DNA, where genes are broken down in pairs and all 5 cases of overlap, allowed by the structure of DNA, were investigated. The second group of characteristics refers to the most extended areas of DNA in which there is no genetic overlap. The interrelation of the established integral characteristics in these groups is shown. As a result, a number of previously unknown effects were discovered. It was possible to establish two functions in which all the over-understood codons in mitochondrial genetic codes (human and other organizations) participate, as well as a significant difference in the integral characteristics of such codes compared to the standard code. Other properties of the structure of the genetic code following from the obtained results are also established. The obtained results allowed us to set and solve one of the new breakthrough problems—the calculation of the genetic code. The full version of the solution to this problem was published in this journal in August 2017.
Guidelines for Optimization of the Absorber Layer Energy Gap for High Efficiency Cu(In,Ga)Se2 Solar Cells  [PDF]
N. Severino, N. Bednar, N. Adamovic
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.64015
Abstract: This work investigates in-depth the effects of variation of the compositional ratio of the absorber layer in Cu(In,Ga)Se2 (CIGS) thin-film solar cells. Electrical simulations were carried out in order to propose the most suitable gallium double-grading profile for the high efficiency devices. To keep the model as close as possible to the real behavior of the thin film solar cell a trap model was implemented to describe the bulk defects in the absorber layer. The performance of a solar cell with a standard CIGS layer thickness (2 μm) exhibits a strong dependence on the front grading height (decreasing band gap toward the middle of the CIGS layer). An absolute gain in the efficiency (higher than 1%) is observed by a front grading height of 0.22. Moreover, simulation results show that the position of the plateau (the region characterized by the minimum band gap) should be accurately positioned at a compositional ratio of 20% Ga and 80% In, which corresponds to the region where a lower bulk defect density is expected. The developed model demonstrates that the length of the plateau is not playing a relevant role, causing just a slight change in the solar cell performances. Devices with different absorber layer thicknesses were simulated. The highest efficiency is obtained for a CIGS thin film with thicknesses between 0.8 and 1.1 μm.
Page 1 /197983
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.