Síntesis de nanopartículas de TiO2 con alta área superficial para degradación de contaminantes en agua

Síntesis de nanopartículas con baja aglomeración a partir del método sol-gel, con el uso de un surfactante Polivinilpirrolidona PVP.El dióxido de titanio es uno de los materiales más importantes y básicos de nuestra vida diaria, ha emergido como un material con excelente propiedades fotocatalíticas para la purificación del medio ambiente. Sin embargo existen limitaciones debido a la naturaleza de la muestra que impiden que incremente su eficiencia de degradación de colorantes orgánicos. La originalidad de este proyecto consiste en sintetizar dióxido de titanio con alta área superficial. El preparar materiales a escala nanométrica tiene grandes ventajas debido a que para alguna aplicaciones los materiales incrementan sus propiedades enormemente. Sin embargo para el proceso de fotocatálisis existe un fenómeno que disminuye su eficiencia, llamado “aglomeración”. Dicho fenómeno consiste en que las partículas con tamaño nanométrico, se unen mediante fuerzas electrostáticas, reduciendo el área expuesta. En este proyecto se trabajaron con surfactantes orgánicos que tienen la función de evitar que las partículas se aglomeren y con ello aumenten su eficiencia fotocatalítica. Los resultados de microscopía electrónica de barrido de alta resolución muestran que el surfactante tiene el efecto que se deseaba debido a que se muestran partículas menos aglomeradas. Dicha propiedad aumento la eficiencia de degradación del azul de metileno general, el cual presenta deplorables condiciones

Clinical utility of two-dimensional Doppler echocardiographic techniques for estimating pulmonary to systemic blood flow ratios in children with left to right shunting atrial septal defect, ventricular septal defect or patent ductus arteriosus

Range gated two-dimensional Doppler echocardiographic methods were evaluated for quantifying pulmonary (QP) to systemic (QS) blood flow ratios. Twenty-one patients were studied, 4 with patent ductus arteriosus, 6 with atrial septal defect and 11 with ventricular septal defect. The Doppler pulmonary to systemic flow (QP:QS) estimation method involved calculating volume flow (liters/min) at a variety of intracardiac sites by using imaging information for flow area and Doppler outputs to calculate mean flow velocity as a function of time. Area volume flows were combined to yield QP:QS ratios. The sites sampled were main pulmonary artery, ascending aorta, mitral valve orifice and subpulmonary right ventricular outflow tract. The overall correlation between Doppler QP:QS estimates and those obtained at cardiac catheterization (n = 18) or radionuclide angiography (n = 3) was r = 0.85 (standard error of the estimate = 0.48:1). These preliminary results suggest that clinical application of this Doppler echocardiographic method should allow noninvasive estimation of the magnitude of cardiac shunts

Pre- and post-surgical evaluation of the inflammatory response in patients with aortic stenosis treated with different types of prosthesis

Abstract Background The inflammatory process in aortic valvular stenosis persists after surgery to replace the valve in almost half of the patients. No association has been found to its persistence. The main objective of this study was to evaluate the inflammatory response in patients with aortic stenosis through the determination of several biomarkers in plasma measured before and after the valvular replacement and to seek an association with the type of prosthesis used. Methods This is an observational study with a follow up of 6 months in subjects with severe aortic stenosis. Seric concentrations of TNFa, IL-1, IL-6 and ICAM and echocardiographic variables were quantified previous to the surgery and a week and 6 months after it. A group of control subjects paired by age and gender was included. Results Seventy-nine subjects were studied of which 57% were male; the average age was of 59 (± 11.4) years. Previous to surgery, the concentration of cytokines was higher in patients than in control subjects. A biological prosthesis was implanted in 48 patients and a mechanical prosthesis in 31. Both, types of prosthesis have components made of titanium. The echocardiograms 1 week and 6 months after the surgery showed a decrease in the mean aortic gradient and an increase in the valvular area (p = 0.001). Half of the patients still showed high proinflammatory cytokine levels. There were no differences according to the type of prosthesis implanted after adjustments for demographic variables, comorbidities and echocardiographic data. Conclusions The inflammatory response caused by both types of valvular prothesis at 6 months after implantation were similar. Both types of prosthesis are recommended, they had similarities in hemodynamic profiles registered with Doppler echocardiography. Age of the patient or the suitability use of anticoagulants determines the type of prosthesis to be used

Bioprosthesis in aortic valve replacement: long-term inflammatory response and functionality

Background: The evaluation of long-term inflammatory response and function in postoperative patients with aortic valve replacement (AVR) deserves special analysis because it is important to try to prevent reoperation and improve durability and functionality of the prostheses. It is our objectiveMethodsIn this study, we included a cohort of patients with aortic valve damage treated by AVR with mechanical prosthesis, bio prosthesis and we included a control group.ResultsWe found that IL-4 and osteopontin levels were higher in patients with mechanical vs biological prostheses (p=0.01 and p=0.04, respectively), osteoprotegerin (OPG) levels were decreased (p=0.01), women had lower levels of ET-1 and IL-6, (p=0.02) (p=0.04), respectively. Patients older than 60 years had decreased levels of IL-1ß pThe findings provide us with the opportunity to effectively treat patients with AVR in the postoperative period, which could prolong the functionality of the bio prostheses. Trial registration number NCT04557345.</jats:p