Sheets made from poly (butylene succinate) (PBS) were prepared by extrusion. They have been studied under uniaxial drawing as a function of the draw condition. Changes in molecular orientation and crystallinity were investigated using the criteria of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile testing, sonic modulus, X-ray diffraction, density, birefringence and measurements of % Haze. Rolling improved the thermo-mechanical and dynamic properties of extruded sheets as a result of changes in molecular orientation and crystallinity.
Fibers of poly (butylene succinate) (PBS) were prepared using a single screw extruder at various take-up speeds. Changes in fiber structure, morphology and physical properties were investigated using sonic velocity measurements and X-ray diffraction. High take up speeds enhanced some of the properties of PBS fibers as a consequence of changes in molecular orientation and crystallinity. Spherulites of PBS were also obtained at 90°C.
La infección por VIH suprime el sistema inmune al aumentar el riesgo de adquirir una infección por un virus del papiloma humano de alto riesgo (VPH-AR), la persistencia y, en último caso, el desarrollo de cáncer de cérvix. Objetivo: Caracterizar los genotipos del VPH, describir las características sociodemográficas y epidemiológicas, y establecer la asociación entre el VPH y las variables clínicas de monitoreo en las mujeres VIH positivo que acudieron a la UAI-HR de marzo de 2019 a agosto de 2021. Método: Investigación descriptiva-transversal retrospectiva en 406 mujeres con VIH. Se llevó a cabo un muestreo no probabilístico de casos consecutivos; los datos fueron analizados en el software Jamovi, mediante el cálculo de frecuencias y porcentajes para variables categóricas y a través de tablas de contingencia, empleando la prueba de chi cuadrado. Resultados: Se encontró una frecuencia de genotipos del VPH-AR de 36.95% (150/406), predominando otros VPH-AR (95, 76.0%). El rango de edad que más se presentó (58, 39.5%) fue de 30 a 39 años. La mayor frecuencia de positividad para genotipos de VPH-AR fue en pacientes con recuentos mayores a 500 células/ µL (30.6%, 66) y con cargas virales del VIH indetectables (28.3%,53). Conclusión: La frecuencia de genotipos del VPH-AR evidencia la importancia de realizar el tamizaje para el mismo en las pacientes de diagnóstico reciente del VIH, así como la búsqueda periódica del VPH a toda mujer negativa en su primera prueba.
The large use of plastics in the world generates a large amount of waste which persists around 200 years in the environment. To minimize this effect is important to search some new polymer materials: the blends of biodegradable polymers with synthetic polymers. It is a large area that needs an intensive research to investigate the blends properties and its behavior face to the different treatments to aim at the biodegradation. The blends used in this work are: some biodegradable polymers such as: poly(hydroxybutyrate) (PHB) and poly(8-polycaprolactone) (PCL) with a synthetic polymer, polypropylene (PP), in lower concentration. These blends were prepared using an internal mixer (Torque Rheometer), and pressed. These films were submitted to fungus biotreatment. The films analyses will be carried out by Fourier Transform Infrared (FTIR), UV-Vis absorption (UV-Vis), Scanning Electronic Microscopy (SEM), DSC and TGA.
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