Construcción de un equipo para desgaste abrasivo según norma ASTM G–65

This work shows the construction and fine tuning of equipment for abrasive wear tests with dry sand rubber wheel "DSRW", according to ASTM G-65. Initially equipment components are described, some of which were purchased commercially and others were built. Subsequently the calibration of next variables was performed: diameter and hardness rubber coating, grain size, moisture and abrasive flow, motor speed and force applied to the specimen. Validation of equipment operation is then performed according to procedure B, using different types of material: gray iron, bronze and nickel-based coatings (Metaceram 23075 and Nitec 10224), repeatability presenting the results for each material. By applying statistical methods, the coefficient of variation was determined, which was below the maximum limit allowed in the standard (6%). Finally, the analysis of wear scars by scanning electron microscopy is performed, being wear mechanism typical of ductile and fragile materials.Este trabajo muestra la construcción y puesta a punto de un equipo para ensayos de desgaste abrasivo con arena seca y rueda de caucho “DSRW”, según norma ASTM G-65. Inicialmente se describen los componentes del equipo, de los cuales, algunos se adquirieron comercialmente y otros se construyeron. Posteriormente se realizó la calibración de las siguientes variables: diámetro y dureza del recubrimiento de caucho, tamaño de grano, humedad y flujo del abrasivo, velocidad del motor y fuerza ejercida sobre la probeta.  Luego se validó el funcionamiento del equipo según procedimiento B, usando diferentes tipos de materiales: hierro gris, bronce y recubrimientos a base de níquel (Metaceram 23075 y Nitec 10224); presentándose repetitividad en los resultados para cada material. Al aplicar los métodos estadísticos,  se determinó el coeficiente de variación, el cual dió por debajo del límite máximo permitido en la norma (6%). Finalmente se realiza el análisis de las huellas de desgaste por microscopía electrónica de barrido, encontrándose los mecanismos de desgaste típicos de los materiales dúctiles y frágiles.

GestaltMatcher Database - A global reference for facial phenotypic variability in rare human diseases

The most important factor that complicates the work of dysmorphologists is the significant phenotypic variability of the human face. Next-Generation Phenotyping (NGP) tools that assist clinicians with recognizing characteristic syndromic patterns are particularly challenged when confronted with patients from populations different from their training data. To that end, we systematically analyzed the impact of genetic ancestry on facial dysmorphism. For that purpose, we established the GestaltMatcher Database (GMDB) as a reference dataset for medical images of patients with rare genetic disorders from around the world. We collected 10,980 frontal facial images - more than a quarter previously unpublished - from 8,346 patients, representing 581 rare disorders. Although the predominant ancestry is still European (67%), data from underrepresented populations have been increased considerably via global collaborations (19% Asian and 7% African). This includes previously unpublished reports for more than 40% of the African patients. The NGP analysis on this diverse dataset revealed characteristic performance differences depending on the composition of training and test sets corresponding to genetic relatedness. For clinical use of NGP, incorporating non-European patients resulted in a profound enhancement of GestaltMatcher performance. The top-5 accuracy rate increased by +11.29%. Importantly, this improvement in delineating the correct disorder from a facial portrait was achieved without decreasing the performance on European patients. By design, GMDB complies with the FAIR principles by rendering the curated medical data findable, accessible, interoperable, and reusable. This means GMDB can also serve as data for training and benchmarking. In summary, our study on facial dysmorphism on a global sample revealed a considerable cross ancestral phenotypic variability confounding NGP that should be counteracted by international efforts for increasing data diversity. GMDB will serve as a vital reference database for clinicians and a transparent training set for advancing NGP technology.</p

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

Construcción de un equipo para desgaste abrasivo según norma ASTM G–65

Este trabajo muestra la construcción y puesta a punto de un equipo para ensayos de desgaste abrasivo con arena seca y rueda de caucho “DSRW”, según norma ASTM G-65. Inicialmente se describen los componentes del equipo, de los cuales, algunos se adquirieron comercialmente y otros se construyeron. Posteriormente se realizó la calibración de las siguientes variables: diámetro y dureza del recubrimiento de caucho, tamaño de grano, humedad y flujo del abrasivo, velocidad del motor y fuerza ejercida sobre la probeta.  Luego se validó el funcionamiento del equipo según procedimiento B, usando diferentes tipos de materiales: hierro gris, bronce y recubrimientos a base de níquel (Metaceram 23075 y Nitec 10224); presentándose repetitividad en los resultados para cada material. Al aplicar los métodos estadísticos,  se determinó el coeficiente de variación, el cual dió por debajo del límite máximo permitido en la norma (6%). Finalmente se realiza el análisis de las huellas de desgaste por microscopía electrónica de barrido, encontrándose los mecanismos de desgaste típicos de los materiales dúctiles y frágiles.

Geotechnical characterisation of neutralised red mud for use in civil engineering construction and manufacturing

Red mud is a toxic by-product from the hot, caustic refining of bauxite to produce alumina, and is produced in the form of an aqueous slurry. It is typically thickened, and transported to a surface storage facility. The volume of red mud generated worldwide is increasing dramatically, leading to a massive amount of red mud to be stored annually. In order to alleviate the ongoing demand for the storage of red mud, means by which it may be used in civil engineering construction and manufacturing are being investigated. Its suitability for use demands that it's geotechnical and geochemical behaviour and parameters be better understood. The geotechnical characterisation of the red mud sample involved the determination of its as­supplied moisture content, specific gravity, particle size distribution, and Atterberg limits. The geochemical characterisation of the red mud sample involved the determination of its paste electrical conductivity, pH, chemistry and mineralogy, which also influence its mechanical behaviour and responses to external loading. The critical geotechnical parameters of red mud, such as compaction, shear strength, compressibility and permeability, also need to be determined, as a function of its moisture state. This paper describes the results of a series of geotechnical and geochemical characterisation and geotechnical parameter testing of a red mud sample to determine its applicability and potential uses in civil engineering construction and manufacturing applications

Estabilidad física y química de preparaciones líquidas extemporáneas elaboradas a partir de tabletas de captopril

Se estudió la estabilidad de preparaciones líquidas extemporáneas para administración peroral, elaboradas  a partir de tabletas de captopril de dos marcas comerciales del mercado nacional colombiano, codificadas como A y B, utilizando solventes de uso común en hospitales. Vehículo 1: agua destilada + vitamina C 10 %  (98 % : 2 %), Vehículo 2: dextrosa 10 % en agua destilada + vitamina C 10 % (98 % : 2 %). Las muestras fueron almacenadas a 5 ºC, 25 ºC y 40 ºC. La cuantificación del fármaco se realizó utilizando una metodología analítica HPLC, previamente validada. Los resultados indicaron que la temperatura es el factor que mayor incidencia presenta sobre el tiempo de vida útil de las preparaciones líquidas extemporáneas desarrolladas, siendo la condición de 40 ºC la menos favorable, en segundo lugar se ubicó el factor vehículo, en donde el vehículo 1 presentó un efecto mayor sobre la estabilidad,  mientras que finalmente  las marcas comerciales  evaluadas presentaron  comportamientos similares.The stability of oral liquid preparations compounded extemporaneously from two brands of Captopril tablets from the Colombian national market, coded as A and B was studied.  The triturate tablets were incorporated in two vehicles used commonly in the hospital, e.g. V-1: distilled water : vitamin C (98 % : 2 %)  and  V-2: dextrose 10 % in distilled water : vitamin C (98 % : 2 %), and stored at 5 °C, 25 °C and 40 °C. A previously validated HPLC methodology was used as method of analysis. Based on the results it may conclude that the temperature is the factor that shows a more incidence in the shelf time of the formulations compounded extemporaneously followed by the vehicle nature. However, the two brands have similar behaviors. The worst conditions obtained are 40 °C and vehicle No. 1