Immobilization of enological pectinase in calcium alginate hydrogels: A potential biocatalyst for winemaking

A biocatalyst was obtained by immobilizing an enological commercial pectinase within calcium alginate hydrogels using an entrapment technique, and its catalytic activity was evaluated during different storage conditions. Hydrogel beads were stored at 4 °C in three different ways: (i) wet, in citrate buffer solution (pH 3.8); (ii) dehydrated by using a vacuum stove; and (iii) freeze-dried. Biocatalyst surface and their internal morphology were characterized by Scanning Electron Microscopy and a good enzyme distribution throughout alginate matrix was observed. Fourier Transform Infrared Spectroscopy results confirmed the presence of absorption bands associated with amino groups present in enzymes. Immobilization procedure did not modify the optimal pH and temperature (pH = 4.0 and 20 °C) for pectinase activity, comparing to free enzyme. Entrapped pectinase showed activity until six reaction cycles with 40% residual activity. Storage stability studies demonstrated that wet entrapped pectinase retained its initial enzymatic activity up to 11 weeks, whereas that lyophilized hydrogels retained its original activity after 8 months of storage. These results suggest that immobilized pectinase may be successfully exploited in various industrial applications, with special concern in grape juice clarification process. Thus, the turbidity of grape must decreased significantly using the immobilized pectinase during 150 min at 20 °C. This biocatalyst could be easily removed after clarification process and it can be reused, minimizing production economic costs in wine industry.Fil: Martín, María Carolina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Lopez, Olivia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Ciolino, Andrés Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Morata, Vilma Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; ArgentinaFil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Ninago, Mario Daniel. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin

Prueba de hipótesis estadística. Estudio de dificultades conceptuales en estudiantes de grado y de postgrado

La práctica de consultoría estadística nos ha revelado algunas dificultades y errores de investigadores de distintas disciplinas en la utilización de las pruebas de hipótesis estadísticas, particularmente, en la interpretación de resultados. Estas dificultades pudieran tener origen y solución desde la formación universitaria, por lo que nuestro propósito es describir la naturaleza de esas dificultades en el contexto de estudiantes universitarios e investigadores sudamericanos. Aunque el problema que plantean esas dificultades y su prevención puede estudiarse desde la complejidad de sus componentes sistémicas, esta investigación se centra en la epistemológica y en la cognitiva. Se realizó un estudio exploratorio aplicando una encuesta, adaptada de la utilizada por Vallecillos (1996), a una muestra de estudiantes de grado y a otra de postgrado. Se analizan en este trabajo los resultados relativos al nivel de significación

Nephron segment-specific gene expression using AAV vectors.

AAV9 vector provides efficient gene transfer in all segments of the renal nephron, with minimum expression in non-renal cells, when administered retrogradely via the ureter. It is important to restrict the transgene expression to the desired cell type within the kidney, so that the physiological endpoints represent the function of the transgene expressed in that specific cell type within kidney. We hypothesized that segment-specific gene expression within the kidney can be accomplished using the highly efficient AAV9 vectors carrying the promoters of genes that are expressed exclusively in the desired segment of the nephron in combination with administration by retrograde infusion into the kidney via the ureter. We constructed AAV vectors carrying eGFP under the control of: kidney-specific cadherin (KSPC) gene promoter for expression in the entire nephron; N

User preferences and water use savings owing to washbasin taps retrofit:a case study of the DECivil building of the University of Aveiro

During the last decades, achieving water efficiency in buildings has increasingly become an important challenge in the scope of sustainability. Water consumption is directly related to individual conduct. Despite the various technological improvements in fixtures and appliances, their performance will be influenced by human preferences and behavior. As a result, the potential for effective water consumption saving is influenced by behavior change as well as water-efficient fixtures and appliances. This work evaluates the impact of user preferences and behavior change on the water-efficient performance of tap aerators in a case study building: the Department of Civil Engineering building of the University of Aveiro, Portugal. Four aerators with different discharge reductions and types were installed in the toilet’s washbasins and the user’s preferences and behavior change measured through direct and online questionnaires. It was observed that the effective water consumption reduction (15 to 49%) was less than the discharge reduction (30 to 70%), confirming that user factors influence water savings. Water use reductions in the tested range (2.0 to 6.7 l/min) also varied according to gender, with male users using less water than their female counterparts. It was noted that an awareness of sustainability values prevailed amongst the users when confronted with the choice between comfort and water efficiency, although differences were observed in the user preferences regarding the various aerators. When confronted with the information that the lower discharge aerator would contribute to a reduction of about 70% on the water discharge, 25% of the users agreed with its use, even if it resulted in a certain degree of dissatisfaction. In comparison, only 8% of the users completely disagreed with its installation. On average, the water consumption reduction was 46% smaller than the discharge reduction achievable with the aerator alone. This further confirms the user factors inform the degree of water savings that is achievable from water-efficient fittings and fixtures

Formação de Professores no Brasil em Pensamento Computacional: uma Revisão Sistemática de Literatura

O Pensamento Computacional (PC) pode auxiliar o desenvolvimento de competências para a resolução de problemas em diversos contextos.  Embora ainda não exista um consenso específico acerca de sua definição, seu desenvolvimento deve ser propiciado aos estudantes na escola básica. No Brasil, a Base Nacional Comum Curricular (BNCC) propõe o desenvolvimento do PC aliado à disciplina de Matemática. Para tanto, é necessário que o professor tenha domínio sobre essas competências, bem como utilize metodologias que favoreçam o desenvolvimento do PC de seus estudantes. Este artigo tem como objetivo apresentar um estudo realizado por meio de um levantamento nas teses e dissertações que abordam como está sendo efetuada a formação dos professores que atuam na Educação Básica diante desse novo contexto. A coleta ocorreu em duas bases de dados brasileiras. Apenas oito trabalhos se enquadram como pesquisas de campo envolvendo a formação inicial ou continuada de professores, apontando a necessidade de se ampliarem estudos a respeito do tema. Ressaltamos a importância de a formação proporcionar ao professor a reconstrução do conhecimento na perspectiva do Technological Pedagogical Content Knowledge (TPACK), a fim de desenvolver práticas que enfoquem o PC de maneira transversal, para que os estudantes possam assumir-se como protagonista de suas aprendizagens

Estudio de prefactibilidad para la creación de una empresa certificadora de trabajo seguro en alturas en el municipio de Soacha.

Elaborar un estudio de prefactibilidad, para la creación de una empresa certificadora en trabajo seguro en alturas ubicada en el municipio de Soacha.El presente documento contiene los principales aspectos a considerar para realizar un estudio de prefactibilidad para la implementación de una empresa certificadora de trabajo seguro en alturas, aplicado al municipio de Soacha. El objetivo es elaborar un plan de trabajo en el cual se apliquen las técnicas, los requisitos exigidos por la normatividad y se genere recursos económicos por medio de capacitaciones teórico prácticas, que estén comprometidas con el desarrollo del talento humano y la responsabilidad al momento de trabajar en alturas. En este trabajo se desarrollan objetivos, planteamiento del problema, justificación, estudio de mercado, tamaño, localización, ingeniería, aspectos legales y administrativos, inversiones, presupuesto, entre otros

A Perspective on PEF Synthesis, Properties, and End-Life

This critical review considers the extensive research and development dedicated, in the last years, to a single polymer, the poly(ethylene 2,5-furandicarboxylate), usually simply referred to as PEF. PEF importance stems from the fact that it is based on renewable resources, typically prepared from C6 sugars present in biomass feedstocks, for its resemblance to the high-performance poly(ethylene terephthalate) (PET) and in terms of barrier properties even outperforming PET. For the first time synthesis, properties, and end-life targeting-a more sustainable PEF-are critically reviewed. The emphasis is placed on how synthetic roots to PEF evolved toward the development of greener processes based on ring open polymerization, enzymatic synthesis, or the use of ionic liquids; together with a broader perspective on PEF end-life, highlighting recycling and (bio)degradation solutions