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Search Results: 1 - 10 of 349276 matches for " E. León "
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Ocular complication of malar fracture and its handling. Case report
León Miguel E.
Colombia Médica , 2004,
Abstract: Antecedents: The superior orbital fissure syndrome (SOFS) is a rare complication in patient with maxillofacial fractures, that consists of a direct compression or hematoma of the structures related to the SOFS. The characteristic clinics are: gross and persistent edema of the periorbital tissues; proptosis and subconjuntival echyimosis; ptosis and ophtalmoplegia; dilatation of the pupil; direct light, reflex absent, inderect reflex (consensual) present; loss of the accommodation reflex; loss of corneal reflex; anesthesia of the eyelid and the front; radiological evidence of reduction in the dimensions of the SOF. Objetive: The objective of this report is to present a clinical case of a patient who underwent the syndrome of the superior orbitaria fissure, its the pos surgery handling and results. Materials: It is presented a clinical case of a 20-year-old age patient, who in his postoperatorio immediate of fracture reduction malar presented the characteristic clinics and radiological of the SOFS. An updated revision of the subject and the different options from treatment appears. Results: This case was handled quickly with megadosis of corticoides and the patient recovered totally his normal visual function. Conclusions: The conducted treatment was successful.
Patterns of Genetic Diversity of the White-Nosed Coati Reveals Phylogeographically Structured Subpopulations in Mexico  [PDF]
Adrián Silva-Caballero, Gloria León-ávila, David Valenzuela-Galván, Jesús E. Maldonado, Jorge Ortega
Natural Resources (NR) , 2017, DOI: 10.4236/nr.2017.81003
Abstract: Coatis (Procyonidae; Nasua) are considered the only truly social meso-carnivore mammals in Neotropical forests. In Mexico, white-nosed coatis (Nasua narica) are suspected to have undergone population reduction due to habitat loss and fragmentation and led to a lack of genetic adaptability and genetic isolation throughout its range. We examined patterns of genetic diversity and connectivity of five populations of Nasua narica distributed throughout Mexico (n = 60) by sequencing an ≈ 800 bp fragment of the mitochondrial cytochrome-b gene and also by screening 12 microsatellite loci. We found moderate to high levels of genetic variability for both genetic markers. We recorded twenty-two different cytochrome-b haplotypes throughout the 5 sampled areas and found that each of the sampled population of white-nosed coatis in Mexico harbors unique haplotypes and only three haplotypes were shared among two different populations that were closer geographically. All populations had high haplotype diversity (h) (0.968 ± 0.008 (SD)) but lower levels of nucleotide diversity (π) of 0.007 ± 0.001 (SD). All microsatellite loci were polymorphic in all of the populations and the mean number of alleles per locus was 5.033 ± 1.545 (SD) with expected (HE) and observed (HO) heterozygosity values of 0.774 and 0.664, respectively. However, low Wright F statistic values suggest the existence of a reduced heterozygosity (FST = 0.203, FIS = 0.134 and FIT = 0.310). Significant differences between the five populations confirmed isolation by distance, which suggests genetic structure among five subpopulations.
SYNTHESIS AND CHARACTERIZATION OF THE LAMELLAR OXYCHLORIDE C0(2)CU4TE4O11CL4
RUIZ - LEóN,D; SPODINE,E;
Journal of the Chilean Chemical Society , 2008, DOI: 10.4067/S0717-97072008000200012
Abstract: in this work we describe the synthesis and characterization of the co2cu4te4o11cl4 phase prepared by the hydrothermal technique. from the polycrystalline x-ray diffraction pattern the obtained new phase was indexed in the p-l space group with cell parameters a= 9.274(7), b= 12.132(2), c= 9.252(2) ?, á = 98.18(14), ? = 108.22(13) and γ = 111.07(8) °. the nominal composition and morphology were obtained using sem-edx measurements. the optical band gap of the material corresponds to an insulating system with 2.7 ev, and the thermogravimetric data shows that the phase is stable up to 700 °c.
Escisión de la apófisis unciforme del hueso ganchoso
Valbuena,Sebastián E; Le Viet,Dominique;
Revista de la Asociaci?3n Argentina de Ortopedia y Traumatolog?-a , 2010,
Abstract: background: the hook of the hamate fracture is rare. the diagnosis is generally late and nonunion is frequent. methods: between 1988 and 2005, 14 patients with nonunion of the hook of the hamate were treated surgically with hook excision. we analyzed the following: time to diagnosis, images, and clinical presentation. results were evaluated with the mayo modified wrist score, while the student's t-test was used for the statistical analysis. results: the time to diagnosis was 9 months in average (range 3-204). eight patients had very good results (57.2%), 4 good (28.6%), 1 fair (7.1%) and 1 poor result (7.1%). from 11 athletes, 10 returned to the same level at the final follow up. no major complications were found. conclusions: the excision of the hook of the hamate is an excellent option in case of non-union, allowing a quick return to daily activities.
SYNTHESIS AND CHARACTERIZATION OF THE LAMELLAR OXYCHLORIDE C0(2)CU4TE4O11CL4
D RUIZ - LEóN,E SPODINE
Journal of the Chilean Chemical Society , 2008,
Abstract: In this work we describe the synthesis and characterization of the Co2Cu4Te4O11Cl4 phase prepared by the hydrothermal technique. From the polycrystalline X-ray diffraction pattern the obtained new phase was indexed in the P-l space group with cell parameters a= 9.274(7), b= 12.132(2), c= 9.252(2) , á = 98.18(14), = 108.22(13) and γ = 111.07(8) °. The nominal composition and morphology were obtained using SEM-EDX measurements. The optical band gap of the material corresponds to an insulating system with 2.7 eV, and the thermogravimetric data shows that the phase is stable up to 700 °C.
BINDING OF ROSE BENGAL TO BOVINE SERUM ALBUMIN
ABUIN,E; ASPéE,A; LISSI,E; LEóN,L;
Journal of the Chilean Chemical Society , 2007, DOI: 10.4067/S0717-97072007000200017
Abstract: the association of rose bengal (rb) with bovine serum albumin (bsa) was investigated by absorbance spectroscopy. the binding constant was determined from the effect observed in the absorbance of rb at 548 nm upon addition of the protein according with the benesi-hildebrand treatment. results were obtained in phosphate buffer at ph = 7.0. the effect of the salinity of the buffer and the sensitivity of the binding constant to the presence of urea were also studied. the results obtained allow to conclude that the binding of rb to bsa is dominated by hydrophobic effects
BINDING OF ROSE BENGAL TO BOVINE SERUM ALBUMIN
E ABUIN,A ASPéE,E LISSI,L LEóN
Journal of the Chilean Chemical Society , 2007,
Abstract: The association of Rose Bengal (RB) with bovine serum albumin (BSA) was investigated by absorbance spectroscopy. The binding constant was determined from the effect observed in the absorbance of RB at 548 nm upon addition of the protein according with the Benesi-Hildebrand treatment. Results were obtained in phosphate buffer at pH = 7.0. The effect of the salinity of the buffer and the sensitivity of the binding constant to the presence of urea were also studied. The results obtained allow to conclude that the binding of RB to BSA is dominated by hydrophobic effects
Estudio anátomo-patológico del disco de la articulación temporomandibular en individuos colombianos
Ballesteros A,Luis E; León-S,Fidias E;
Revista médica de Chile , 1999, DOI: 10.4067/S0034-98871999001200008
Abstract: background: the temporomandibular joint is an oval fibrous plate that completely divides the joint and accommodates irregularities existent in the bone articular surfaces. aim: to study the frequency of temporomandibular joint disk abnormalities among colombian subjects. material and methods: we studied 120 temporomandibular joint disks obtained from fresh cadavers arrived in the instituto de medicina legal, in cali colombia. these were analyzed according to subject?s dental status and age. results: nineteen percent of disks had small erosions. in 7,5% of disks there were wider erosions or perforations. twenty six percent of discs were very thin and this alteration was seen mostly in people aged 50 years or older. conclusions: these results are intermediate between those who claim that disk perforations are rare and those who had shown tile opposite. the loss of dental pieces seems to be a risk factor leading to such disk perforation.
Efecto de la temperatura, basicidad, ciclo térmico y potencial oxidante en la formación de fases minerales en briquetas de mineral de hierro
Bedolla, E.,Aguilar, E. A.,León, C. A.
Revista de Metalurgia , 1997,
Abstract: In the present work, the effect of the firing conditions such as temperature, basicity, firing cycle and oxygen potential, on the formation of mineral phases in magnetitic iron ore briquettes was studied. It was found that a high oxygen potential (air) favors the oxidation reaction of magnetite to hematite and as a consequence calcium ferrite formation. The calcium ferrite increased with the increase of the basicity and decreased with the increase of the temperature. At a medium partial pressure of oxygen (ρO2 = 5 x 10-3 atm.), the agglomerate was composed in the majority of magnetite with small amounts of reoxidized hematite and negligible amounts of calcium ferrite. It could be noticed that magnetite increased and hematite decreased with increase of basicity. The mineral phases present in the briquettes fired at the gas mixture composed by 1 % CO, 24 % CO2 and 75 % N2 and then cooled in air, include magnetite and highly oxidized phases such as hematite and calcium ferrite. Se estudió el efecto de las condiciones de sinterización tales como temperatura, basicidad, ciclo térmico y potencial oxidante en la formación de fases minerales en briquetas de mineral de hierro magnetítico. Se encontró que un alto potencial de oxígeno (aire) favorece la reacción de oxidación de magnetita a hematites y como consecuencia la formación de calcioferrita. La calcioferrita se incrementó con el aumento de la basicidad y disminuyó con el incremento de la temperatura. Para un potencial de oxígeno medio (ρO2 = 5 x 10-3 atm.), el aglomerado estuvo compuesto en su mayor parte por magnetita con peque as cantidades de hematites reoxidada y cantidades insignificantes de calcioferrita. Se observó que la magnetita se incrementa y la hematites disminuye con el aumento de la basicidad. Las fases minerales presentes en briquetas sinterizadas en la mezcla gaseosa de 1 % CO, 24 % CO2 y 75 % N2, incluyen la magnetita y fases altamente oxidadas como hematites y calcioferrita.
Aplicación de técnicas cinéticas no isotérmicas en la reducción de tres minerales de hierro de grado comercial
Bedolla, E.,León, C. A.,Aguilar, E. A.
Revista de Metalurgia , 1997,
Abstract: The mechanism of reduction of iron ore agglomerates by both isothermal and nonisothermal TG studies was investigated, and the work was complemented with the structural characterization of the total and partially reacted samples. Three different commercial hematite pellets were studied. The mechanisms of reduction were obtained under isothermal conditions, resulting in a fitting to chemical reaction models. Nonisothermal reduction was carried out using a TGA system (CAHN TG-171) from 600 to 1,000 °C maintaining a lineal heating rate of 4, 7 and 10 °C/min, and the reducing atmospheres used were H2 (100 %) and H2-CO (95:5). The kinetic parameters were evaluated by Coats & Redfern, Dixit & Ray and Prakash & Ray techniques. It was found that the lower the heating rate, the higher the reduction degree and the higher activation energy. The activation energy for reduction with the mixture H2-CO was always higher than that obtained with pure H2. Se estudió el mecanismo de reducción en aglomerados de mineral de hierro mediante análisis termogravimétricos tanto isotérmicos como no isotérmicos, complementando el estudio por caracterización estructural de muestras parcial y completamente reducidas. Se estudiaron tres tipos de pelets hematíticos grado comercial. Los mecanismos de reducción se determinaron isotérmicamente y resultaron ser modelos de control por reacción química. La reducción no isotérmica se realizó en un TGA CAHN-171 de 600 a 1.000 °C a velocidad de calentamiento lineal de 4, 7 y 10 °C/min, en atmósferas reductoras de H2 (100 %) y H2-CO (95:5). Los parámetros cinéticos se evaluaron por las técnicas propuestas por Coats & Redfern, Dixit & Ray y Prakash & Ray. Se encontró que a menor velocidad de calentamiento, mayor es el grado de reducción no isotérmico y mayor la energía de activación del proceso. La energía de activación con la mezcla H2-CO, siempre fue mayor que con H2 puro.
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