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Quintero K.,Central University of Venezuela | Martinez M.,Central University of Venezuela | Hackley P.,U.S. Geological Survey | Marquez G.,University of Huelva | And 3 more authors.
Energy Sources, Part A: Recovery, Utilization and Environmental Effects | Year: 2011

The aim of this work was to carry out a geochemical study of channel samples collected from six coal beds in the Marcelina Formation (Zulia State, western Venezuela) and to determine experimentally the gas content of the coals from the Paso Diablo mine. Organic geochemical analyses by gas chromatography-mass spectrometry and isotopic analyses on-line in coalbed gas samples were performed. The results suggest that the Guasare coals were deposited in a continental environment under highly dysoxic and low salinity conditions. The non-detection of 18α(H)-oleanane does not preclude that the organic facies that gave rise to the coals were dominated by angiosperms. In addition, the presence of the sesquiterpenoid cadalene may indicate the subordinate contribution of gymnosperms (conifers) in the Paleocene Guasare mire. The average coalbed gas content obtained was 0.6 cm 3/g. δ 13C and D values indicate that thermogenic gas is prevalent in the studied coals. Copyright © Taylor & Francis Group, LLC. Source


Naranjo-Briceno L.,Institute Estudios Avanzados IDEA | Pernia B.,Institute Estudios Avanzados IDEA | Guerra M.,Instituto Zuliano Of Investigaciones Tecnologicas Inzit | Demey J.R.,Institute Estudios Avanzados IDEA | And 6 more authors.
Microbial Biotechnology | Year: 2013

Large amount of drilling waste associated with the expansion of the Orinoco Oil Belt (OOB), the biggest proven reserve of extra-heavy crude oil (EHCO) worldwide, is usually impregnated with EHCO and highly salinized water-based drilling fluids. Oxidative exoenzymes (OE) of the lignin-degrading enzyme system (LDS) of fungi catalyse the oxidation of a wide range of toxic pollutants. However, very little evidences on fungal degradation or biotransformation of EHCO have been reported, which contain high amounts of asphaltenes and its biodegradation rate is very limited. The aims of this work were to study the ability of Pestalotiopsis palmarumBM-04 to synthesize OE, its potential to biotransform EHCO and to survive in extreme environmental conditions. Enzymatic studies of the LDS showed the ability of this fungus to overproduce high amounts of laccase (LACp) in presence of wheat bran or lignin peroxidase (LIPp) with EHCO as sole carbon and energy source (1300 U mgP-1 in both cases). FT-IR spectroscopy with Attenuated Total Reflectance (ATR) analysis showed the enzymatic oxidation of carbon and sulfur atoms in both maltenes and asphaltenes fractions of biotreated EHCO catalysed by cell-free laccase-enriched OE using wheat bran as inducer. UV-visible spectrophotometry analysis revealed the oxidation of the petroporphyrins in the asphaltenes fraction of biotreated EHCO. Tolerance assays showed the ability of this fungus to grow up to 50000 p.p.m. of EHCO and 2000mM of NaCl. These results suggest that P.palmarumBM-04 is a hopeful alternative to be used in remediation processes in extreme environmental conditions of salinity and EHCO contamination, such as the drilling waste from the OOB. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology. Source


Toro R.,University of Los Andes, Venezuela | Bruno-Colmenarez J.,Instituto Zuliano Of Investigaciones Tecnologicas Inzit | De Delgado G.D.,University of Los Andes, Venezuela | Delgado J.M.,University of Los Andes, Venezuela
Powder Diffraction | Year: 2013

Clenbuterol hydrochloride is an active pharmaceutical ingredient usually prescribed for treatment of respiratory diseases due to its activity as a decongestant and bronchodilator. It has also been used as a performance- enhancing drug. In the PDF-4/Organics 2012 database there are six entries related to this compound: three for its hydrochloride phase calculated using single-crystal data, two for a MeOH and a DMSO solvate of two Cu-clenbuterol complexes, and one experimental unindexed pattern. In this contribution the powder diffraction pattern and the crystal structure, determined using single crystal X-ray diffraction techniques of clenbuterol hemihydrate, C12H18Cl2N2O·0.5H2O, an unreported phase, are presented. Copyright © International Centre for Diffraction Data 2013. Source


Briceno S.,Venezuelan Institute for Scientific Research | Bramer-Escamilla W.,Venezuelan Institute for Scientific Research | Silva P.,Venezuelan Institute for Scientific Research | Garcia J.,University of Los Andes, Venezuela | And 6 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2014

Nickel ferrite (NiFe2O4) was supported on activated carbon (AC) from petroleum coke (petcoke). Potassium hydroxide (KOH) was employed with petcoke to produce activated carbon. NiFe2O4 were synthesized using PEG-Oleic acid assisted hydrothermal method. The structural and magnetic properties were determined using thermogravimetric and differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), Fourier Transform Infrared (IR-FT), surface area (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). XRD analysis revealed the cubic spinel structure and ferrite phase with high crystallinity. IR-FT studies showed that chemical modification promoted the formation of surface oxygen functionalities. Morphological investigation by SEM showed conglomerates of spherical nanoparticles with an average particle size of 72 nm and TEM showed the formation of NiFe2O4/carbon nanofibers. Chemical modification and activation temperature of 800 C prior to activation dramatically increased the BET surface area of the resulting activated carbon to 842.4 m2/g while the sulfur content was reduced from 6 to 1%. Magnetic properties of nanoparticles show strong dependence on the particle size. © 2014 Elsevier B.V. Source


Fernandez-Delgado M.,Venezuelan Institute for Scientific Research | Rojas H.,Central University of Venezuela | Duque Z.,Instituto Zuliano Of Investigaciones Tecnologicas Inzit | Suarez P.,Simon Bolivar University of Venezuela | And 3 more authors.
Revista do Instituto de Medicina Tropical de Sao Paulo | Year: 2016

Vibrio cholerae represents a significant threat to human health in developing countries. This pathogen forms biofilms which favors its attachment to surfaces and its survival and transmission by water or food. This work evaluated the in vitro biofilm formation of V. cholerae isolated from clinical and environmental sources on stainless steel of the type used in food processing by using the environmental scanning electron microscopy (ESEM). Results showed no cell adhesion at 4 h and scarce surface colonization at 24 h. Biofilms from the environmental strain were observed at 48 h with high cellular aggregations embedded in Vibrio exopolysaccharide (VPS), while less confluence and VPS production with microcolonies of elongated cells were observed in biofilms produced by the clinical strain. At 96 h the biofilms of the environmental strain were released from the surface leaving coccoid cells and residual structures, whereas biofilms of the clinical strain formed highly organized structures such as channels, mushroom-like and pillars. This is the first study that has shown the in vitro ability of V. cholerae to colonize and form biofilms on stainless steel used in food processing. © 2016, Instituto de Medicina Tropical de Sao Paulo. All rights reserved. Source

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