Continuous fractionation of glycerol acetates. Physicochemical properties glycerol acetates + CO2 mixtures at high pressure

Glycerol acetates are high-added value biosurfactants that find applications in different industrial sectors. Previous studies show the supercritical CO2 technology has a great potential for the fractionation of these highly viscous, amphiphilic, and non-volatile products (mono, di, and triacetyl glycerol) according to the quality standards of the food and cosmetic industry [1-3]. A proper design of fractionation columns and their further scale-up to commercial scale requires a robust thermodynamic model for phase equilibrium and PVT predictions [4], as well as proper correlations for physical properties like viscosity to assess the mass transfer and estimate the height of theoretical stages [5]. Physiochemical properties of these multicomponent mixtures are difficult to predict due to the complex nature of this system [6]. Thus, in this work, we determine experimentally the density and viscosity of CO2 saturated glycerol acetates mixtures at different pressures (30 bar to 150 bar), temperatures (25 °C to 50 °C) and CO2 concentrations (30 mol % to 70 mol %). Operating conditions were selected based on phase equilibrium predictions with the GCA-EOS of a high-pressure fractionation column [2]. First, a variable volume equilibrium cell is used to measure bubble points and saturated liquid molar volumes of glycerol acetates + CO2 mixtures. Thereafter, a high-pressure falling ball type viscometer is used to determine the dynamic viscosity of saturated liquid mixtures in the same range of pressure, temperature and CO2 concentrations.Fil: Pereda, Selva. 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; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Fortunatti Montoya, Mariana. 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; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Hegel, Pablo Ezequiel. 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; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina1º Encuentro Ibérico de Fluidos SupercríticosSantiago de CompostelaEspañaUniversidad de Santiago de Compostel

Vanillin as a natural cross-linking agent in chitosan-based films: Optimizing formulation by response surface methodology

One way of improving mechanical and water barrier properties of chitosan films is through cross-linking reactions. Cross-linking agents usually used for this purpose include glutaraldehyde, glyoxal, and formaldehyde, which may cause some undesirable side effects and are consider health hazards. Hence, the objective of this work was to optimize the formulation of chitosan (CH) films with vanillin as a natural antioxidant cross-linking agent, to simultaneously improve their physical, barrier, antioxidant and mechanical properties. Three parameters were studied at three levels: vanillin content (0, 25 and 50% w/w chitosan), glycerol content (30, 45 and 60% w/w chitosan) and drying temperature (35, 50 and 65 °C). Response surface methodology (RSM) and desirability function (D) were used to find the levels of each factor that simultaneously optimize different properties of the films: opacity value, total soluble matter (TSM), Young modulus (YM), T0 and Tmax parameters (obtained from thermogravimetric analysis), water vapor permeability (WVP), total phenolic content (TPC) and antioxidant capacity by DPPH method. Fifteen formulations combining the studied factors were prepared according to a Box-Behnken design. An optimal chitosan film formulation was found, with vanillin content of 37.5% (w/w of CH), glycerol content of 45% (w/w of CH) and drying temperature of 57.5 °C. RSM approach using the desirability function was found to be an effective tool to investigate changes in films properties and to search for the optimal active chitosan film formulation with a natural cross-linking agent, such as vanillin.Fil: Tomadoni, Bárbara María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ponce, Alejandra Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pereda, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ansorena, Maria Roberta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Bio-películas para el envasado de alimentos: proteínas y carbohidratos

Se utilizaron materiales provenientes de recursos renovables y desechos industriales para el desarrollo de películas poliméricas naturales y biodegradables con potencial aplicación en el envasado de alimentos. En particular se seleccionaron un derivado de la caseína que es la proteína que se encuentra en mayor concentración en la leche, denominado caseinato de sodio y, por otra parte un carbohidrato que se obtiene a partir del tratamiento de algunos desechos de la industria marina (principalmente caparazones de crustáceos), denominado quitosano, para preparar películas puras y compuestas. Estas películas son transparentes aunque ligeramente coloreadas, y se biodegradan rápidamente en el suelo. Sin embargo, difieren en otras propiedades (resistencia mecánica, propiedades biocidas, solubilidad en agua) dependiendo de su composición química. Aún así, es posible aprovechar la capacidad formadora de películas del caseinato de sodio, del quitosano o de sus mezclas para formular materiales aplicables al envasado y recubrimiento de alimentos. Materials from renewable resources and industrial wastes were used in the formulation of natural and biodegradable polymer films with potential application in food packaging. In particular, sodium caseinate derived from casein (the main milk protein), and chitosan, a carbohydrate derived from chitin, which is obtained from wastes of the fishing activity (mainly from the shrimp shells), were selected to prepare neat and composite films. All these films are transparent but slightly colored and they are rapidly biodegraded in soil. However, they can show other very different properties, such as mechanical strength, biocide properties or water solubility, depending on their chemical composition. In any case, it is possible and convenient to take advantage of their interesting properties as film formers to formulate materials applicable to food packaging and coating.Fil: Pereda, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Moreira, Maria del Rosario. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Departamento de Ingenieria Quimica. Grupo de Inv En Ingenieria En Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Roura, Sara Ines. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Departamento de Ingenieria Quimica. Grupo de Inv En Ingenieria En Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marcovich, Norma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); ArgentinaFil: Aranguren, Mirta Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación en Ciencia y Tecnología de Materiales (i); Argentin

Swine influenza: clinical, serological, pathological, and virological cross-sectional studies in nine farms in Argentina

Background: Influenza A viruses (IAV) are important pathogens responsible for economic losses in the swine industry and represent a threat to public health. In Argentina, clinical, pathological, and virological findings suggest that IAV infection is widespread among pig farms. In addition, several subtypes of IAV, such as pH1N1, H3N2, δ1H1N1, and δ2H1N2, have been reported. Objectives: To evaluate the infection patterns of influenza virus in nine pig farms in Argentina. Methods: Clinical, serological, pathological, and virological cross-sectional studies were conducted. Results: Clinical and pathological results were characteristic of endemic influenza infection in eight of the nine farms studied. By rRT-PCR, six of the nine farms were positive to influenza. Five IAV were obtained. Genome analysis determined that four of the isolations were pH1N1 and that the remaining one was a reassortant human origin H3N2 virus containing pandemic internal genes. Serological results showed that all farms were positive to influenza A antibodies. Moreover, the hemagglutination inhibition test showed that infection with viruses containing HA′s from different subtypes (pH1, δ1H1, δ2H1, and H3) is present among the farms studied and that coinfections with two or more subtypes were present in 80.5% of positive pigs. Conclusions: Because vaccines against IAV are not licensed in Argentina, these results reflect the situation of IAV infection in non-vaccinated herds. This study provides more information about the circulation and characteristics of IAV in a poorly surveyed region. This study provides more data that will be used to evaluate the tools necessary to control this disease.Facultad de Ciencias Veterinaria

Comparison between inmunohistochemestry and PCR for porcine circo virus type 2 detection in linfonodes

El síndrome multisistémico de adelgazamiento postdestete (SMAP) se caracteriza clínicamente por adelgazamiento progresivo, linfoadenomegalia, diarrea, disnea, palidez cutánea e ictericia. La presencia de circovirus porcino tipo 2 (PCV-2) es uno de los factores determinantes para la presentación de SMAP. Las lesiones macroscópicas son agrandamiento de linfonódulos, focos blancos en riñón, hepatomegalia, ulcera gástrica, consolidación pulmonar con edema interlobulillar. Las lesiones microscópicas características son depleción en tejido linfoide e infiltración granulomatosa, nefritis intersticial y neumonía.Facultad de Ciencias Veterinaria

Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs

Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The current study describes the clinical epidemiology, pathology, and molecular and biological characteristics of the virus. Phylogenetic analysis revealed that the virus isolate shared nucleotide identities of 96-98% with H3N2 IAVs that circulated in humans from 2000 to 2003. Antigenically, sera from experimentally inoculated animals cross-reacted mainly with noncontemporary human-origin H3N2 influenza viruses. In an experimental infection in a commercial swine breed, the virus was of low virulence but was transmitted efficiently to contact pigs and caused severe disease when an infected animal acquired a secondary bacterial infection. This is the first report of a wholly human H3N2 IAV associated with clinical disease in pigs in South America. These studies highlight the importance of two-way transmission of IAVs and SIVs between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide.Facultad de Ciencias Veterinaria

Outbreak of swine influenza in Argentina reveals a non-contemporary human H3N2 virus highly transmissible among pigs

Sporadic outbreaks of human H3N2 influenza A virus (IAV) infections in swine populations have been reported in Asia, Europe and North America since 1970. In South America, serological surveys in pigs indicate that IAVs of the H3 and H1 subtypes are currently in circulation; however, neither virus isolation nor characterization has been reported. In November 2008, an outbreak of respiratory disease in pigs consistent with swine influenza virus (SIV) infection was detected in Argentina. The current study describes the clinical epidemiology, pathology, and molecular and biological characteristics of the virus. Phylogenetic analysis revealed that the virus isolate shared nucleotide identities of 96-98% with H3N2 IAVs that circulated in humans from 2000 to 2003. Antigenically, sera from experimentally inoculated animals cross-reacted mainly with noncontemporary human-origin H3N2 influenza viruses. In an experimental infection in a commercial swine breed, the virus was of low virulence but was transmitted efficiently to contact pigs and caused severe disease when an infected animal acquired a secondary bacterial infection. This is the first report of a wholly human H3N2 IAV associated with clinical disease in pigs in South America. These studies highlight the importance of two-way transmission of IAVs and SIVs between pigs and humans, and call for enhanced influenza surveillance in the pig population worldwide.Facultad de Ciencias Veterinaria

La motivación y el significado de la escuela para los jóvenes

El propósito del proyecto de investigación “Representaciones Sociales del trabajo y del estudio en jóvenes de distintos niveles de escolaridad de la Escuela Media” (Programación Científica 2008-2010 UBACyT) es describir las representaciones sociales del trabajo y del estudio de jóvenes que cursan distintos niveles de escolaridad en escuelas públicas de Nivel de Educación Media de la Ciudad de Buenos Aires. Nuestro objetivo es explorar cómo se van configurando dichas representaciones en función de las trayectorias sociales y escolares. Particularmente, nos interesó indagar de qué manera incide la motivación académica en la construcción de las representaciones de sí y de las expectativas de logro futuro. Pensamos que la motivación académica incide en el desarrollo emocional y social, y en la construcción de las representaciones de sí mismo y en las expectativas y posibilidades futuras sobre el estudio y el trabajo de los jóvenes que asisten a escuelas medias pertenecientes a circuitos educativos diferenciados.Eje: Psicología educacional y orientación vocacionalFacultad de Psicologí

La motivación y el significado de la escuela para los jóvenes

El propósito del proyecto de investigación “Representaciones Sociales del trabajo y del estudio en jóvenes de distintos niveles de escolaridad de la Escuela Media” (Programación Científica 2008-2010 UBACyT) es describir las representaciones sociales del trabajo y del estudio de jóvenes que cursan distintos niveles de escolaridad en escuelas públicas de Nivel de Educación Media de la Ciudad de Buenos Aires. Nuestro objetivo es explorar cómo se van configurando dichas representaciones en función de las trayectorias sociales y escolares. Particularmente, nos interesó indagar de qué manera incide la motivación académica en la construcción de las representaciones de sí y de las expectativas de logro futuro. Pensamos que la motivación académica incide en el desarrollo emocional y social, y en la construcción de las representaciones de sí mismo y en las expectativas y posibilidades futuras sobre el estudio y el trabajo de los jóvenes que asisten a escuelas medias pertenecientes a circuitos educativos diferenciados.Eje: Psicología educacional y orientación vocacionalFacultad de Psicologí

Pandemic (H1N1) 2009 outbreak on pig farm, Argentina

In June-July 2009, an outbreak of pandemic (H1N1) 2009 infection occurred on a pig farm in Argentina. Molecular analysis indicated that the virus was genetically related to the pandemic (H1N1) 2009 influenza virus strain. The outbreak presumably resulted from direct human-to-pig transmission.Facultad de Ciencias Veterinaria