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Search Results: 1 - 10 of 481409 matches for " Jorge A. García-Macedo "
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Evaluación de la degradación de un colorante textil usando el fotocatalizadores Fe/TiO2/SiO2 (0.0, 0.5, 0.7, 1.0 % en masa Fe) y en presencia de H2O2
José Manuel Barrera-Andrade,Sayra Lissette Orozco-Cerros,Guadalupe Valverde-Aguilar,Jorge A. García-Macedo
Tecnología, Ciencia, Educación , 2011,
Abstract: En este trabajo se evalúa la degradación de un colorante textil antraquinónico empleando fototalizadores de TiO2 dopados con iones de Fe soportado sobre SiO2, Fe/TiO2/SiO2. Los foto-catalizadores fueron sintetizados para diferentes contenidos de Fe (0, 0.5, 0.7, 1.0% en masa), empleando la técnica de sol-gel. Como fuente de sílice fue empleada sílice pirogénica (tama o de partícula 0.007 um y área superficial de 390±40 m2 g-1) y los precursores de titanio y hierro fueron TiCl4 y Fe(NO3)3, respectivamente. Los soles de TiO2 fueron preparados vía peptización ácida del precipitado de la solución de TiCl4 con NH3H2O. La proporción de TiO2, en los foto-catalizadores Fe/TiO2/SiO2, fue de 10% en masa. Los materiales sintetizados fueron sometidos a un tratamiento térmico de 550°C por 3 horas. Los foto-catalizadores Fe/TiO2/SiO2 se caracterizaron por espectroscopía óptica, en modo de reflectancia difusa UV-Vis-NIR y difracción de rayos X. La degradación del colorante textil se efectuó en solución acuosa en presencia de H2O2 a pH de 3.0. El proceso de degradación fue llevado a cabo en un reactor intermitente (tipo batch) y bajo radiación UV-A. Los resultados demuestran que la actividad catalítica de los fotocatalizadores se incrementó con la introducción de 0.7% de Fe en la matriz TiO2/SiO2.
Effect of lamellar nanostructures on the second harmonic generation of polymethylmethacrylate films doped with 4-(4-nitrophenylazo)aniline chromophores
Alfredo Franco,Laura Romero-Miranda,Guadalupe Valverde-Aguilar,Jorge García-Macedo,Giovanna Brusatin,Massimo Guglielmi
Physics , 2011,
Abstract: The kinetics of the orientation of Disperse Orange 3 molecules embedded in amorphous and nanostructured Polymethylmethacrylate films was studied under the effect of an intense electrostatic poling field. Non-centrosymmetric chromophore distributions were obtained in Polymethylmethacrylate films by Corona poling technique. These distributions depends on the Corona poling time. The changes in the orientation of the Disperse Orange 3 molecules were followed by in-situ transmitted Second Harmonic Generation measurements. The Second Harmonic Generation signal was recorded as function of time at several temperatures; it was fitted as function of the Corona poling time, considering matrix-chromophore interactions. The Polymethylmethacrylate films were nanostructured by the incorporation of an anionic surfactant, the Sodium Dodecyl Sulfate. The lamellar nanostructures in the films were identified by X-ray diffraction measurements.
Decoloración fotocatalítica homogénea y heterogénea de un colorante azoico, empleando como catalizador dióxido de titanio dopado con hierro soportado sobre sílice (Fe/TiO2/SiO2)
S. L. Orozco-Cerros,J. M. Barrera-Andrade,G. Valverde-Aguilar,J. A. García-Macedo
Tecnología, Ciencia, Educación , 2010,
Abstract: En esta investigación se presentan los resultados de la decoloración fotocatalítica homogénea y heterogénea de un colorante azoico, anaranjado de metilo, empleando catalizadores de TiO2 dopados con iones de hierro soportados sobre una matriz de sílice, Fe/TiO2/SiO2. El fotocatalizador Fe/TiO2/SiO2 fue preparado por la técnica sol-gel, en una relación molar de 0.01:0.02:1.0, respecto a la sílice. Adicionalmente, se prepararon los materiales Fe/SiO2 (a una relación molar de 0.01:1) y TiO2/SiO2 (a una relación molar de 0.02:1) por impregnación, como fotocatalizadores de control. Los materiales Fe/SiO2, TiO2/SiO2 y Fe/TiO2/ SiO2 fueron sometidos a un tratamiento térmico a 550°C por 24 horas. La caracterización física y óptica de los fotocatalizadores fue realizada empleando espectroscopía vibracional IR y óptica y difracción de rayos X. Los resultados de la caracterización demuestran que el fotocatalizador Fe/TiO2/SiO2 presenta una banda de absorción en la región visible desde 400 a 600 nm, lo que permitirá un uso más eficiente de la energía solar. Los resultados del proceso de decoloración de anaranjado de metilo demuestran que proceso se lleva a cabo principalmente por fotocatálisis heterogénea. La contribución de la fotocatálisis homogénea es mínima, debido a que la concentración de los iones de hierro en solución de muy baja, del orden de 0.5 mg L-1.
Adipocinas, tejido adiposo y su relación con células del sistema inmune
Sánchez-Mu?oz, Fausto;García-Macedo, Rebeca;Alarcón-Aguilar, Francisco;Cruz, Miguel;
Gaceta médica de México , 2005,
Abstract: a dipokines or adipocytokines are the proteins secreted by the adipose tissue. these bioactive molecules include proteins that modify insulin sensitivity (acylation stimulating protein (asp), tnf-a, il- 6, resistin, leptin and adiponectin), and proteins that have known effects on vascularity (angiotensinogen and the plasminogen inhibitor protein pai-1). several studies have found a close relationship between adipocytes and immune cells as a consequence of evolutionary mechanisms that favor metabolic adaptation and survival under adverse conditions. it is known that adipokines contribute to the inflammation and insulin resistance present in obese individuals. the aim of this review is to analyze current information related to the physiology of the adipose tissue, with a special emphasis on the secretion of adipokines and their role in inflammation. we recommend that therapies addressing the treatment of obesity related disorders should focus on modifying the inflammatory process that originates in the adipose tissue.
El papel de la inmunidad innata en la obesidad
Fortis,ángeles; García-Macedo,Rebeca; Maldonado-Bernal,Carmen; Alarcón-Aguilar,Francisco; Cruz,Miguel;
Salud Pública de México , 2012, DOI: 10.1590/S0036-36342012000200014
Abstract: obesity in mexico is alarmingly increasing in prevalence in adults and children, and it is a risk factor for the development of insulin resistance, as well as, of other metabolic alterations. the discovery of the expression of the toll-like receptors (tlrs) in adipocytes, suggests an important role in innate immunity. in different models of obesity, there has been observed an increase of tlrs expression in the fat tissue, therefore tlrs could be involved in systemic inflammation in this disease, and in the development of insulin resistance. tlr activation is mediated by fatty acids and their expression is regulated by leptin, adiponectin and ppars. knowledge of the role of tlrs in inflammation and adipocyte differentiation and their regulation, then it is important to try to develop new therapeutic anti-inflammatory targets that contribute in the treatment of obesity.
Adiponectin in eutrophic and obese children as a biomarker to predict metabolic syndrome and each of its components
Miguel Klünder-Klünder, Samuel Flores-Huerta, Rebeca García-Macedo, Jesús Peralta-Romero, Miguel Cruz
BMC Public Health , 2013, DOI: 10.1186/1471-2458-13-88
Abstract: A cross sectional study was conducted in 190 school-age children classified as obese and 196 classified as eutrophic. Adiponectin, glucose, insulin, high density lipoprotein cholesterol (HDL-C) and triglycerides were determined from a fasting blood sample. Height, weight, waist circumference, systolic and diastolic blood pressures (BP) were measured; MetS was evaluated with the IDF definition. The study groups were divided according to tertiles of adiponectin, using the higher concentration as a reference. Linear regression analysis was used to assess the association between adiponectin and components of the MetS. Finally, stepwise forward multiple logistic regression analysis controlling for age, gender, basal HOMA-IR values and BMI was performed to determine the odds ratio of developing MetS according to adiponectin tertiles.Anthropometric and metabolic measurements were statistically different between eutrophic and obese children with and without MetS (P <0.001). The prevalence of MetS in obese populations was 13%. Adiponectin concentrations were 15.5?±?6.1, 12.0?±?4.8, 12.4?±?4.9 and 9.4?±?2.8 μg/mL for eutrophic and obese subjects, obese without MetS, and obese with MetS, respectively (P <0.001). Obese children with low values of adiponectin exhibited a higher frequency of MetS components: abdominal obesity, 49%; high systolic BP, 3%; high diastolic BP, 2%; impaired fasting glucose, 17%; hypertriglyceridemia, 31%; and low HDL-C values, 42%. Adjusted odds ratio of presenting MetS according to adiponectin categories was 10.9 (95% CI 2.05; 48.16) when the first tertile was compared with the third.In this sample of eutrophic and obese Mexican children we found that adiponectin concentrations and MetS components have an inversely proportional relationship, which supports the idea that this hormone could be a biomarker for identifying individuals with risk of developing MetS.During the last three decades, obesity has emerged worldwide as an epidemic affecting all age
Tratamento cirúrgico para ectasia anulo-aórtica
García-Macedo, Ricardo;Kalil, Renato A. K;Prates, Paulo Roberto;Lucchese, Fernando A;Sant'Ana, Jo?o Ricardo;Pereira, Edemar M;Costa, Altamiro Reis;Lara, Raul Feck A;Nesralla, Ivo A;
Revista Brasileira de Cirurgia Cardiovascular , 1986, DOI: 10.1590/S0102-76381986000100007
Abstract: this is a report of 27 patients presenting annulo-aortic ectasia submitted to surgical correction with a composite valve-tube graft (bentall-de bono technique), between 1976 and 1985. twenty three (85.2%) had cystic medial necrosis, 3 (11,1%) were chronic aortic disections and 1 (3.7%) was luetic aortitis. age ranged from 29 to 64 years (m = 48). three were female and 24 male patients. the valves used were homologous dura maier in 7 cases, heterologous aorta in 9 and mechanical prosthesis in 11. functional class (nyha) was i-ii in 7 and iii-iv in 9 patients. there was 1 (3.7%) hospital death, due to bleeding and renal failure. significant early complications were represented by arrhythmias in 13 cases (48%) and bleeding in 3 (11%). in the late follow-up therev.were 9 deaths, due to: sudden death (2 patients, 7.4%), bleeding in reoperation (1 patient, 3.7%), hospital infection (1 patient, 3.7%), infectious endocarditis (1 patient, 3.7%) and accidental causes (2 patients, 7.4%). five patients (18.5%) needed reoperation in the late follow-up: 2 due to bioprosthetic failure, 2 for replacement of an infected dacron tube and 1 for repair of pseudo-aneurysm and periprosthetic leak. the actuarial survival curve showed a probability of 83.7% up to the 3rd. year, 61 % for the 5th. year and 42.7% from the 6th. to the 9th. year of follow-up. the 17 patients surviving are in functional class i-ii (nyha). the composite valve-dacron tube graft (bentall-de bono) technique for correction of annulo-aortic ectasia is associated with a low hospital mortality. the improvement in functional class is significant. there have been a small number of complications and the long term survival is very satisfactory.
?Envenenamiento por consumo de Asclepias curassavica o nematodiasis gastrointestinal en ovinos en pastoreo? Hallazgos de un estudio de caso
Macedo Barragán, Rafael;Arredondo Ruiz, Victalina;Ramírez Rodríguez, Julia;García Márquez, Luis Jorge;
Veterinaria México , 2009,
Abstract: a case study was conducted with the objective to describe and determine whether the occurrence of sheep poisoning was due to milkweed asclepias curassavica or an acute case of gastrointestinal nematosis. milkweed population and distribution as well as animal data such as grazing behavior and poisoning symptoms were collected in the field. a necropsy was carried out with the objective to describe histopathological findings in relation to the observed symptomatology and confirm poisoning diagnosis. symptoms such as inability to stand, muscle paralysis, salivation, diarrhea, followed by facial edema and death, began when the animals grazed on native grass prairie with a scarcity of forage but a high density of a. curassavica. nevertheless, the study of the grazing behavior in the area where there were intoxication cases showed only exploratory contacts between lambs and milkweed. necropsy findings showed diffuse edema of the subcutaneous tissue (anasarca), serous fat atrophy, poor development of pale muscles, hydrothorax, hydropericardium, hydroperitoneum and abomasum containing blood, mucous, and abundant blood-sucking nematodes haemonchus contortus with no evidence of poisoning. these findings indicated a severe mucohemorrhagic abomasum inflammation and generalized edema associated with a hypoproteinemia due to an acute haemonchosis as the cause of death.
Envenenamiento por consumo de Asclepias curassavica o nematodiasis gastrointestinal en ovinos en pastoreo? Hallazgos de un estudio de caso
Rafael Macedo Barragán,Victalina Arredondo Ruiz,Julia Ramírez Rodríguez,Luis Jorge García Márquez
Veterinaria México , 2009,
Abstract: Se realizó un estudio de caso con el objetivo de documentar la posible ocurrencia de envenenamiento por el consumo de Asclepias curassavica o de casos agudos de nematodiasis gastrointestinal en ovinos en pastoreo. Se registró la densidad de población, la ubicación espacial de la maleza y el tipo de vegetación; además, se observaron los hábitos de pastoreo del reba o y la semiología mostrada por los ovinos afectados. Posteriormente se realizó una necropsia con la finalidad de describir hallazgos histopatológicos relacionados con la semiología observada, que confirmaran el diagnóstico de envenenamiento. El estudio de campo mostró que la aparición de signos característicos de envenenamiento, como incoordinación, parálisis muscular, salivación, diarrea, seguidos por edema facial y muerte, inició cuando los animales pastaban bajo condiciones propicias para la ingestión de la planta tóxica: mala oferta de forraje y abundante población de A. curassavica. El estudio de los hábitos de pastoreo en el área en que se presentaron los casos de intoxicación, sólo mostró acercamientos y consumos de A. curassavica de tipo exploratorio, mientras que la necropsia mostró un edema generalizado del tejido subcutáneo (anasarca) con atrofia serosa de la grasa y músculos pálidos con mal desarrollo, hidrotórax, hidropericardio, hidroperitoneo y abomaso con presencia abundante de sangre, moco y nematodos del género Haemonchus contortus sin evidencias de intoxicación. Se concluye que la muerte de los animales se debió a abomasitis mucohemorrágica severa difusa y edemas generalizados asociados con una hipoproteinemia causados por hemoncosis aguda.
La tortura en el marco de la guerra sucia en México: un ejercicio de memoria colectiva
Mendoza García, Jorge;
Polis , 2011,
Abstract: during the last century's 60's and 70's, in mexico, guerrilla groups emerged all over the country; equally in rural areas such as the state of guerrero, as in cities like monterrey, guadalajara and mexico city. in facing this wave of armed groups, the mexican state resorted not to the law but to violent strategies, surpassing even the legal frameworks instituted in the country. this terrifying manner of confronting the guerrillas was known as guerra sucia (dirty war). it displayed multiple tactics such as illegal imprisonment, forced disappearance, detention of guerrillas' kin and torture. torture was practiced equally on men and women accused of being guerrillas or of providing support to these groups. branding, beatings, mutilations, and even the introduction of objects into the body, were some of the manners that torture adopted in this guerra sucia. by means of several testimonies presented as an exercise of collective memory, this essay aims to reconstruct some of the experiences of those decades and, at the same time, clarify the use of bodily violence by those who exert terror through power.
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