In the last decade, an increasing number of glycosaminoglycans (GAGs), chitin and chitosan applications have been reported. Their commercial demands have been extended to different markets, such as cosmetics, medicine, biotechnology, food and textiles. Marine wastes from fisheries and aquaculture are susceptible sources for polymers but optimized processes for their recovery and production must be developed to satisfy such necessities. In the present work, we have reviewed different alternatives reported in the literature to produce and purify chondroitin sulfate (CS), hyaluronic acid (HA) and chitin/chitosan (CH/CHs) with the aim of proposing environmentally friendly processes by combination of various microbial, chemical, enzymatic and membranes strategies and technologies.
The aim of this work was to study the recovery of proteolytic and collagenolytic activities from rayfish (Raja clavata) viscera wastes. Initially, different parts of the gastrointestinal tract by-products (stomach, duodenum section including pancreas, final intestine) were evaluated. The extracts from proximal intestine yielded the highest values of both enzymatic activities. Optimal conditions for protease activity quantification were established at pH = 6, T = 40 °C and incubation time ≤20 min. The mathematical equation used to model the joint effect of pH and temperature led to maximum activity at pH = 8.66 and 59.4 °C, respectively. Overcooled acetone was found to be best option for recovery of enzymatic activities in comparison with ethanol, PEG-4000, ammonium sulphate and ultrafiltration system. Finally, a simple and systematic protocol of partial purification and total recovery of proteases and collagenases was defined.
The most common method in the routine determination of uronic acids, the m-hydroxydiphenyl reaction, recently adapted to rapid microplate analysis, has as a main inconvenience, in any one of their modalities, interferences due to the frequent presence of proteins and neutral carbohydrates in the samples. Corresponding corrections in the literature are unsatisfactory when applied to complex matrices, and further adaptation to the microplate analysis is not free from additional problems. With particular reference to hyaluronic acid, the interactions between the principal reactants and the interfering materials are studied kinetically under realistic conditions, and simple mathematical models are proposed which satisfactorily describe the experimental results and allow adequate corrections to be made.
It was conducted a literature review on the relationship between masculinities and emotions, both understood as social constructs that respond to particular contexts. The principal aim is to describe the scientific production considering some parameters proposed by bibliometric studies. A comprehensive search of articles based on the definition of specific keywords and criteria according to a wide variety of databases of full text documents. The results of the systematization review show a very slow growth of these studies since the year 2000. More than a half of the studies were carried out in only two countries. There is a predominance of qualitative approach, particularly theoretical methods, such as ethnography, grounded theory and social constructionism. From the topics discussed in each of the studies, we propose a categorization to describe them and discuss implications of the emotions in the configuration of masculinities.
A new generation of extractant impregnated resin has been elaborated by encapsulation of extractants in biopolymer capsules. The extractant forms the core of the spherical particle, while the biopolymer entraps the extractant in a shell. The immobilization can reduce the loss of extractant. Cyanex 302 (bis(2,4,4‐trimethylpentyl)monothiophosphinic acid) was efficiently immobilized into alginate capsules prepared by ionotropic gelation in CaCl2 solutions. The influence of a series of parameters on microcapsule preparation was investigated. Selected materials were tested for Pd(II) recovery from HCl solutions through the study of sorption isotherms and uptake kinetics.
Objetivo. Identificar las representaciones sociales (RS) del cáncer de mama en mujeres con diagnóstico y mujeres sanas o libres de enfermedad (MLE), Guadalajara-Jalisco, 2016. Método. Se aplicó la técnica asociativa de listados libres y cuestionario de pares a 40 mujeres; para conocer la estructura de las RS se hizo análisis de contenido temático y estructural de la RS. Resultados. Los hallazgos muestran que las mujeres diagnosticadas tienen mayor conciencia sobre la importancia de prevención y detección oportuna. MLE otorgaron mayor importancia a aspectos negativos como miedo y muerte. La RS sobre la enfermedad se construye a través de las vivencias, ya sea propia con el diagnóstico o a través de experiencias de una persona cercana o conocimientos sociales.
Objetivo Identificar el contenido y organización de las representaciones sociales que tiene la población urbana de tres ciudades de América Latina sobre el COVID-19.Materiales y Métodos Estudio cualitativo hecho desde la antropología cognitiva a través del análisis estructural de las representaciones sociales. Se utilizaron técnicas de listados libres y comparación de pares de febrero a abril de 2020 en Pereira (Colombia), en la zona metropolitana de Guadalajara (México) y en León (también en México). Participaron 97 personas de ambos sexos (97 en la primera fase y 71 en la segunda), mayores de edad y que su ocupación o profesión no tuvieran relación con el área de salud; se realizó muestreo no probabilístico-propositivo.Resultados El imaginario sociocultural está asociado con términos como contagio y pandemia, con énfasis en los términos relacionados con la prevención de la enfermedad.Conclusiones Los saberes de la población sobre el COVID-19 privilegian aspectos clínicos y epidemiológicos, así como las medidas de contención y mitigación.
Objetivo Estimar el intervalo serial y el número básico de reproducción de COVID-19 entre casos importados durante la fase de contención en Pereira, Colombia, 2020.Método Se realizó un estudio cuantitativo para determinar algunos aspectos de la dinámica de transmisión de la COVID-19. Se utilizaron las entrevistas epidemiológicas de campo en los que se incluyeron 12 casos confirmados por laboratorio con PCR-RT para SARS-CoV-2 importados y sus correspondientes casos secundarios confirmados, entre los que estaban contactos familiares y sociales.Resultados Los intervalos seriales en la COVID-19 se ajustan a una distribución Gamma, con una media del intervalo serial de 3,8 días (± 2,7) y un R0 de 1,7 (IC 95% 1,06-2,7) inferior a lo encontrado en otras poblaciones con inicio del brote.Conclusiones Un intervalo serial inferior al periodo de incubación como el que se estimó en este estudio sugiere un periodo de transmisión presintomático que, según otras investigaciones, alcanza un pico promedio a los 3,8 días, hecho que sugiere que durante la investigación epidemiológica de campo la búsqueda de contactos estrechos se realice desde al menos 2 días antes del inicio de síntomas del caso inicial.
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