Composición química y actividades biológicas de Annona muricata L

Colombia es un país biodiverso en flora y fauna, donde las especies vegetales son de gran importancia porque a partir de estas se pueden generar medicamentos para el tratamiento de patologías y el desarrollo de materias primas en la producción de bienes y servicios. La utilización de medicamentos derivados de plantas se remonta a la antigüedad y es una costumbre que ha perdurado en el tiempo. Un ejemplo es Annona muricata L, popularmente conocida como “Guanábana”. En la literatura existe evidencia de las diversas actividades biológicas que presentan los metabolitos secundarios de esta planta, entre ellos, gran cantidad de compuestos antimicrobianos. Lo anterior es de vital importancia, debido a que la resistencia a los antimicrobianos convencionales es una constante amenaza global. La búsqueda de nuevas moléculas de origen natural con menores efectos secundarios y con posibles diferentes rutas o mecanismos de acción que los antibióticos tradicionales brindan una herramienta para combatir estas problemáticas. Por lo anterior se propuso una búsqueda exhaustiva de los compuestos reportados en la literatura de A. muricata, y sus respectivas actividades biológicas haciendo énfasis en los compuestos con actividad antimicrobiana en las bases de datos científicas, reportes institucionales entre otros documentos verificables, en los últimos 5 años.Universidad Libre Seccional Barranquilla -- Facultad de Ciencias Exactas y Naturales -- MicrobiologíaColombia is a bio-diverse country in terms of flora and fauna, where plant species has high importance because they can be used to generate medicines for the treatment on pathologies and the development of raw materials for the production of assets and services. The use of medicines derived from plants dates back to ancient times and is a practice that has endured over time. One example is Annona muricata L, popularly known as "Guanábana". In the literature there is evidence of the diverse biological activities presented in the secondary metabolites of this plant, including a large number of antimicrobial compounds. This is particularly important because resistance to conventional antimicrobials is a constant global challenge. The research for new molecules derived from natural sources with fewer side effects and with different possible routes or mechanisms than traditional antibiotics provides a tool to combat these problems. Therefore, an exhaustive search of the compounds reported in the literature of A. muricata, and their respective biological activities was proposed, with emphasis on compounds with antimicrobial activity in scientific databases, institutional reports and other reliable documents, in the last 5 years

Distributed X-ray dosimetry with optical fibers by Optical Frequency Domain Interferometry

This article reports on the first demonstration of in situ, real-time dosimetry realized with an enhanced backscatttering optical fiber, and a high resolution optical backscattering reflectometry measurement. This work is devised to overcome the current problems in monitoring radiotherapy treatments, in particular, the difficult evaluation of not only the actual X-ray dose that is accumulated on the target volume but also the distribution profile of the ionizing radiation beam. Overall, the research aims at developing a dose sensor with the most demanding features of small form factor, spatial profiling, and remote interrogation. The experiments have been conducted by evaluating the spatial profile of radiation-induced spectral shift of the Rayleigh backscattering along an optical fiber exposed to X-rays. The sensing element is a section of specialty optical fiber whose Rayleigh backscattering signature changes under ionizing radiation. The specialty fiber is designed to exhibit an enhanced backscattering, in order to overcome the poor sensitivity to radiation of standard optical fibers that are normally, used in telecommunications. The enhanced sensitivity is achieved by doping the core with either aluminum or magnesium nanoparticles, and two different fibers have been fabricated and tested. The experimental results show the capability of real time detection of the radiation profile from high-dose rates (700 Gy/min) to low-dose rates (2 Gy/min). Moreover, different sensing mechanisms and responses to high- and low-dose rates are evidenced. A comparison with a quasi-distributed sensing system based on an array of fiber Bragg gratings (FBGs) is discussed, highlighting the superior performance of the backscattering approach in terms of sensitivity and spatial resolution, whereas the array of FBGs exhibits an advantage in terms of sampling speed