1,022 research outputs found

    Evaluación Bidimensional y Tridimensional de la Vía Aérea Superior

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    Indexación: Scopus; Scielo.The aim of this study was to validate and correlate the two-dimensional (2D) with the three-dimensional (3D) measures of the upper airway assessment. Lateral cephalograms and cone beam CT of 100 adult subjects were used to perform a 2D and 3D assessment of the upper airway. Spearman correlation coefficient was used to determine whether there was correlation between variables. Additionally, specificity, sensitivity, negative predictive value and positive predictive value was calculated for the 2D assessment of the upper airway. Correlation between all two and three dimensional variables was found. In the nasopharynx and oropharynx, a weak correlation (r <0.51) was found; in the oropharynx a moderate one (0.50 <r <0.76). The validity tests of the 2D assessment resulted in a 73% sensitivity, 45% specificity, 93% negative predictive value and 14% positive predictive value for the nasopharynx; 100% sensitivity, 51% specificity, 100% negative predictive value and 6% positive predictive value in the oropharynx and 100% sensitivity, 71% specificity, 100% negative predictive value and 13% positive predictive value in the hypopharynx. There is a weak correlation between the 2D and 3D assessment of the upper airway. However, the lateral cephalogram has a high sensitivity and high negative predictive value, therefore, an additional complementary examination would not be necessary if the 2D assessment of the upper airway throws a normal result.http://ref.scielo.org/mpkrn

    Mathematical modeling of injury healing process under the action of an active pharmaceutical ingredient (API)

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    In this work we carried out the mathematical modeling of the wound healing process, which is a well documented topic in medical and biological practice; but mathematically speaking there are still too much to be done for a clear understanding of the healing phenomom. Here we contribute to the mathematical modelling by using chemical kinetic concepts and mathematical tools, from which we have been able to formulate a system of ordinary differential equations of initial value, whose solution is presented graphically in front of a case study, where we have tested an active pharmaceutical principle with respect to its effectiveness. Finally, the speed of the healing process for such a case study produced an excellent agreement with experimental data that has been omitted due to confidentiality.En este trabajo llevamos a cabo el modelado matemático del proceso de curación de heridas, que es un tema bien documentado en la práctica médica y biológica; pero matemáticamente hablando, todavía hay mucho por hacer para una comprensión clara del fenómeno curativo. Aquí contribuimos al modelado matemático mediante el uso de conceptos de cinética química y herramientas matemáticas, a partir de los cuales hemos podido formular un sistema de ecuaciones diferenciales ordinarias de valor inicial, cuya solución se presenta gráficamente frente a un estudio de caso, donde hemos probado un principio farmacéuticamente activo con respecto a su eficacia. Finalmente, la velocidad del proceso de curación para tal estudio de caso produjo un excelente acuerdo con los datos experimentales, que se han omitido debido a la confidencialidad

    Optimization of the Position of the CR-39 Polycarbonate Sheet Inside the Solid State Track Detector “Measuring Device” Through Computational Fluid Dynamics Technique

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    The “measuring device” is one of the most reliable, efficient and economic indoor radon dosimeters that exist. This device was developed by the Proyecto de Aplicaciones de la Dosimetría (PAD) at the Physics Institute of UNAM (IF-UNAM) and consists of a transparent rigid plastic cup, a CR-39 polycarbonate sheet and a standard size metal clip that is used to hold the polycarbonate in the center of the cup. The cup is wrapped and covered with a low-density polyurethane protector in order to prevent the detector from being irradiated by ionizing particles found in the environment. In this work, an analysis was carried out that allowed to understand how the radon concentration on the polycarbonate sheet varies when its height is changed with respect to the base of the plastic cup, in order to understand what position increase the probability of interaction between radon and the surface of the detector. For the development of this work, four computational simulations were performed with the technique called Computational Fluid Dynamics (CFD). The results shows that as the CR-39 is positioned more closed to the base of the cup, the probability of interaction of the radon and the detector increase. Based on these results it is concluded that, when there is a limit in the time in which a measuring device can be placed in the zone where it is desired to quantify indoor radon, it is recommended to collocated the CR-39 at 1 cm with respect to the base of the cup

    Interrelationship between skin sensitization, rhinitis, and asthma in patients with allergic rhinitis: a study of Spain and Portugal

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    OBJECTIVE: Allergic rhinitis can determine the presence and type of asthma. The main aim of this study was to evaluate the link between allergic rhinitis, asthma, and skin test sensitization in patients with allergic rhinitis. METHODS: Patients with allergic rhinitis, aged 10 to 50 years, were consecutively enrolled at different allergy centers in Spain and Portugal. All the patients underwent skin prick tests with a panel of 20 biologically standardized aeroallergens. Allergic rhinitis was classified according to etiology and the Allergic Rhinitis and its Impact on Asthma guidelines and asthma was classified according to the Global Initiative for Asthma guidelines. RESULTS: A total of 3225 patients, with a mean age of 27 years, were evaluated. House dust mites and grass and olive tree pollens were the most common aeroallergens. The mean (SD) number of positive skin tests per patient was 6.5 (4), the mean wheal size was 42.3 (28) mm2, and the mean atopy index was 6.5 (2). Forty-nine percent of the patients had concomitant asthma. Asthma severity was associated with a longer time since onset (P < .04) and allergic rhinitis severity (P < .001). Patients with concomitant asthma had a significantly higher number of aeroallergens and sensitization intensity than those without asthma (P < .001). CONCLUSIONS: In this broad population sample, the presence and type of asthma was influenced by skin sensitization and both time since onset and severity of allergic rhinitis

    General and stereoselective aminoxylation of biradical titanium(IV) enolates with TEMPO: a detailed study on the effect of the chiral auxiliary

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    A comprehensive analysis of the influence of the chiral auxiliary on the α-aminoxylation of titanium(IV) enolates with TEMPO indicated that (S) 4-tert-butyl-1-oxazolidine-2-thione is the most appropriate scaffold to provide a single diastereomer in high yields for a variety of substrates, which converts such a radical reaction into a highly chemo- and stereoselective oxidatio

    Proposal of a water-quality index for high andean basins: application to the Chumbao river, Andahuaylas, Peru

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    Thewater fromthe high Andean rivers is peculiar due to its composition and the geomorphology of its sources, and naturally or anthropogenically contamination is not discarded along its course. This water is used for agriculture and human consumption, therefore knowing its quality is important. This research aimed to proposing and formulate a water-quality index for high Andean basins through the Delphimethod, and its application in the Chumbao River located in Andahuaylas-Peru. Forty-three water-quality parameters were evaluated through the Delphi method, and the water-quality index (WQIHA) was formulated with a weighted average of the weights of the selected parameters, it was compared with the WQI Dinius. For this purpose, ten sampling points were considered along the Chumbao River located between 4274 and 2572 m of altitude and theWQIHA was applied. In addition, field and laboratory analyses were carried out in 2018, 2019, and 2021, in dry and rainy seasons. Twenty parameters were grouped in the physicochemical sub-index (SIPC), heavy metals sub-index (SIHM), and organic matter sub-index (SIOM). Each group contributed with weights of 0.30, 0.30, and 0.40, respectively, for theWQIHA formulation. The SIPC and SIOM showed that the areas near the head of the basin presented excellent and good quality, while the urbanized areas were qualified as marginal to poor; SIHM reported good quality in all points and seasons. Regarding the WQIHA, the index shows good quality in the zones above 3184 m of altitude, contrasting with poor quality downstream, decreasing notably in both seasons, suggesting continuous degradation of the water body

    Experimental and computational evidence of the biradical structure and reactivity of titanium(IV) enolates

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    Quantum chemical calculations have unveiled the unexpected biradical character of titanium(IV) enolates from N-acyl oxazolidinones and thiazolidinethiones. The electronic structure of these species therefore involves a valence tautomerism consisting of an equilibrium between a closed shell (formally Ti(IV) enolates) and an open shell, biradical, singlet (formally Ti(III) enolates) electronic states, whose origin is to be basically found in changes of the Ti−O distance. Spectroscopic studies of the intermediate species lend support to such a model, which also turns out to be crucial for a better understanding of the overall reactivity of titanium(IV) enolates. In this context, a thorough computational analysis of the radical addition of titanium(IV) enolates from N-acyl oxazolidinones to TEMPO has permitted us to suggest an entire mechanism, which accounts for the experimental details and the diastereoselectivity of the process. All together, this evidence highlights the relevance of biradical intermediates from titanium(IV) enolates and may be a useful contribution to the foundations of a more insightful comprehension of the structure and reactivity of titanium(IV) enolates

    Comparative life cycle analysis between commercial porcelain stoneware and new ones designed by using volcanic scraps

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    : To achieve carbon neutrality by 2050, many companies have started implementing sustainability policies. The aim of this work, as result of collaboration between Universities and companies, is to assess the environmental impacts associated with the production of alternative formulations of porcelain stoneware. The proposed formulations contain extraction scraps and chamotte and have promising technological properties. A comparative analysis of the life cycle in three different scenarios was carried out to assess the environmental footprint of the final products. The analyzed scenarios were a glazed porcelain stoneware (which was taken as a reference and is commercially available), a porcelain stoneware containing pumice scraps, and one containing volcanic lapillus scraps. It was observed that the transportation of raw materials has the largest environmental impact, followed by the production and extraction of the raw materials themselves. From the performed analysis, it was possible to observe that by replacing the currently used materials by the ones hereby studied, environmental benefits can be obtained. In particular, depending on the considered pollutant, the environmental impact can be reduced between a minimum of about 8 % (Freshwater Aquatic Ecotoxicity category) to a maximum of 48 % (Acidification category). In a time when raw materials supply is difficult, the use of scraps, which would otherwise be disposed of, is particularly interesting and can lead to the production of an environmentally friendly product
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