Implications of storage and handling conditions on glass transition and potential devitrification of oocytes and embryos

Devitrification, the process of crystallization of a formerly crystal-free, amorphous glass state, can lead to damage during the warming of cells. The objective of this study was to determine the glass transition temperature of a cryopreservation solution typically used in the vitrification, storage, and warming of mammalian oocytes and embryos using differential scanning calorimetry. A numerical model of the heat transfer process to analyze warming and devitrification thresholds for a common vitrification carrier (open-pulled straw) was conducted. The implications on specimen handling and storage inside the dewar in contact with nitrogen vapor phase at different temperatures were determined. The time required for initiation of devitrification of a vitrified sample was determined by mathematical modeling and compared with measured temperatures in the vapor phase of liquid nitrogen cryogenic dewars. Results indicated the glass transition ranged from -126°C to -121°C, and devitrification was initiated at -109°C. Interestingly, samples entered rubbery state at -121°C and therefore could potentially initiate devitrification above this value, with the consequent damaging effects to cell survival. Devitrification times were calculated considering an initial temperature of material immersed in liquid nitrogen (-196°C), and two temperatures of liquid nitrogen vapors within the dewar (-50°C and -70°C) to which the sample could be exposed for a period of time, either during storage or upon its removal. The mathematical model indicated samples could reach glass transition temperatures and undergo devitrification in 30seconds. Results of the present study indicate storage of vitrified oocytes and embryos in the liquid nitrogen vapor phase (as opposed to completely immersed in liquid nitrogen) poses the potential risk of devitrification. Because of the reduced time-handling period before samples reach critical rubbery and devitrification values, caution should be exercised when handling samples in vapor phase.Fil: Sansinena, Marina Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Santos, Maria Victoria. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Taminelli, Guillermo Luis. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Zaritzky, Noemi Elisabet. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

Implications of storage and handling conditions on glass transition and potential devitrification of oocytes and embryos

Devitrification, the process of crystallization of a formerly crystal-free, amorphous glass state, can lead to damage during the warming of cells. The objective of this study was to determine the glass transition temperature of a cryopreservation solution typically used in the vitrification, storage, and warming of mammalian oocytes and embryos using differential scanning calorimetry. A numerical model of the heat transfer process to analyze warming and devitrification thresholds for a common vitrification carrier (open-pulled straw) was conducted. The implications on specimen handling and storage inside the dewar in contact with nitrogen vapor phase at different temperatures were determined. The time required for initiation of devitrification of a vitrified sample was determined by mathematical modeling and compared with measured temperatures in the vapor phase of liquid nitrogen cryogenic dewars. Results indicated the glass transition ranged from -126°C to -121°C, and devitrification was initiated at -109°C. Interestingly, samples entered rubbery state at -121°C and therefore could potentially initiate devitrification above this value, with the consequent damaging effects to cell survival. Devitrification times were calculated considering an initial temperature of material immersed in liquid nitrogen (-196°C), and two temperatures of liquid nitrogen vapors within the dewar (-50°C and -70°C) to which the sample could be exposed for a period of time, either during storage or upon its removal. The mathematical model indicated samples could reach glass transition temperatures and undergo devitrification in 30seconds. Results of the present study indicate storage of vitrified oocytes and embryos in the liquid nitrogen vapor phase (as opposed to completely immersed in liquid nitrogen) poses the potential risk of devitrification. Because of the reduced time-handling period before samples reach critical rubbery and devitrification values, caution should be exercised when handling samples in vapor phase.Fil: Sansinena, Marina Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Santos, Maria Victoria. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Taminelli, Guillermo Luis. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Zaritzky, Noemi Elisabet. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

Specifying quality characteristics and attributes for E-Learning sites

Education involves a continuous process of exploration, acquisition, organization, integration and delivery of information and knowledge. In recent years, e-learning sites and applications have exponentially started to grow, being a central phenomenon for the industry and education fields. Key factors for the present and future success of these applications and organizations are, on one hand, the fulfillment of technological standards for e-learning environments, and, on the other hand, the utilization of well-defined development processes and the production of required quality. One of our current concerns is the quality assessment of e-learning sites and applications. In this paper, a taxonomy of e-learning sites and applications, and ultimately the quality requirements for the Functionality characteristic are thoroughly described, regarding an intentional audience. An evaluation case study for this domain, using the WebQEM (Quality Evaluation Methodology) strategy is being runned.Eje: Tecnología informática aplicada en la EducaciónRed de Universidades con Carreras en Informática (RedUNCI

Income and beyond: Multidimensional poverty in six Latin American countries

This paper presents empirical results of a wide range of multidimensional poverty measures for: Argentina, Brazil, Chile, El Salvador, Mexico and Uruguay, for the period 1992–2006. Six dimensions are analysed: income, child attendance at school, education of the household head, sanitation, water and shelter. Over the study period, El Salvador, Brazil, Mexico and Chile experienced significant reductions of multidimensional poverty. In contrast, in urban Uruguay there was a small reduction in multidimensional poverty, while in urban Argentina the estimates did not change significantly. El Salvador, Brazil and Mexico together with rural areas of Chile display significantly higher and more simultaneous deprivations than urban areas of Argentina, Chile and Uruguay. In all countries, access to proper sanitation and education of the household head are the highest contributors to overall multidimensional poverty.Multidimensional poverty measurement, counting approach, Latin America, Unsatisfied Basic Needs, rural and urban areas.

Bridging the Gap between Security/Risk and Quality

An IT security vulnerability can be considered as an inherent weakness in a target system that could be exploited by a threat source. The underlying hypothesis in our proposal is that each identified attribute associated with the target entity to be controlled should show the highest quality satisfaction level as an elementary indicator. The higher the quality indicator value achieved per each attribute, the lower the vulnerability indicator value and therefore the potential impact from the risk standpoint. In the present work, we discuss the added value of supporting the IT security and risk assessment areas with measurement and evaluation (M&E) methods and strategy, which are based on metrics and indicators. Also we illustrate excerpts of an M&E case study for characteristics and attributes of Security, and their potential risk assessment.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Using web-site QEM to measure the quality of sites

In this position paper, the main steps to measure and evaluate quantitatively the quality of sites are shown. Besides, some specific models, criteria and procedures to apply in these activities are discussed by quoting case studies already performed (e.g., in the academic domain [4] as well as in museums [3] and e-commerce domain [6]). In order to get a general insight, we focus on the overview oí the proposed methodology called Web-site Quality Evaluation Method '(QEM). The proposed stepwise, expert-driven, model-based methodology is essentially quantitative, flexible, and robust covering most of the activities in the evaluation, comparison, and ranking process oí websites.Eje: Ingeniería de software y base de datosRed de Universidades con Carreras en Informática (RedUNCI

Bridging the Gap between Security/Risk and Quality

An IT security vulnerability can be considered as an inherent weakness in a target system that could be exploited by a threat source. The underlying hypothesis in our proposal is that each identified attribute associated with the target entity to be controlled should show the highest quality satisfaction level as an elementary indicator. The higher the quality indicator value achieved per each attribute, the lower the vulnerability indicator value and therefore the potential impact from the risk standpoint. In the present work, we discuss the added value of supporting the IT security and risk assessment areas with measurement and evaluation (M&E) methods and strategy, which are based on metrics and indicators. Also we illustrate excerpts of an M&E case study for characteristics and attributes of Security, and their potential risk assessment.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Estudios del comportamiento fisiológico de la semilla de granadilla (passiflora ligularis juss.) para la conservación ex situ

El genotipo de una especie vegetal comprende una diversidad genética per se que posee un valor para el presente o el futuro, y constituye un patrimonio de la humanidad de valor incalculable, por tanto, su pérdida es un proceso irreversible que supone una grave amenaza para la estabilidad de los ecosistemas, el desarrollo agrícola y la seguridad alimentaria. La conservación de los recursos genéticos de los frutales andinos ha sido poco implementada y en especial la ex situ, ya que permite mantener una gran representatividad de la variabilidad presente en cada taxa (Ocampo, 2007). La granadilla es la segunda especie en importancia económica del género Passiflora L., por su consumo en fresco en los mercados nacionales e internacionales. A pesar de esto, no hay información disponible que permita a los productores preservar la semilla de los mejores genotipos de cada cosecha sin deteriorar su calidad. El objetivo de este estudio es determinar el comportamiento fisiológico de la semilla frente al almacenamiento, y proponer estrategias para la conservación ex situ