Experimental determination of surface heat transfer coefficient in a dry ice-ethanol cooling bath using a numerical approach

Background: Dry ice-ethanol bath (-78ºC) have been widely used in low temperature biological research to attain rapid cooling of samples below freezing temperature. The prediction of cooling rates of biological samples immersed in dry ice-ethanol bath is of practical interest in cryopreservation. The cooling rate can be obtained using mathematical models representing the heat conduction equation in transient state. Additionally, at the solid cryogenic-fluid interface, the knowledge of the surface heat transfer coefficient (h) is necessary for the convective boundary condition in order to correctly establish the mathematical problem. Objective: The study was to apply numerical modeling to obtain the surface heat transfer coefficient of a dry ice-ethanol bath. Materials and methods: A numerical finite element solution of heat conduction equation was used to obtain surface heat transfer coefficients from measured temperatures at the center of polytetrafluoroethylene and polymethylmetacrylate cylinders immersed in a dry ice-ethanol cooling bath. The numerical model considered the temperature dependence of thermophysical properties of plastic materials used. Results: A negative linear relationship is observed between cylinder diameter and heat transfer coefficient in the liquid bath, the calculated h values were 308, 135 and 62.5 W/(m2K) for PMMA 1.3, PTFE 2.59 and 3.14 cm in diameter, respectively. Conclusion: The calculated heat transfer coefficients were consistent among several replicates; h in dry ice-ethanol showed an inverse relationship with cylinder diameter.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Rheological properties of honey from Burkina Faso: loss modulus and complex viscosity modelling

This is an Author's Accepted Manuscript of an article published in International Journal of Food Properties, 19, 11, 2575-2586 © Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/10942912.2015.1136938[EN] This study evaluated the rheological behaviour of Burkina Faso honey and the use of exponential and polynomial models to predict the influence of chemical composition and temperature on the viscoelastic parameters: complex viscosity (ç*) and loss modulus (G ). Samples were first characterized by evaluating: water activity, 5-hydroxy methyl furfural (HMF), sugars (fructose, glucose and sucrose), electrical conductivity, moisture and colour. Dynamic rheological properties were obtained at different temperatures (5, 10, 15, 20, 25, 30 and 40°C). All the honeys displayed Newtonian behaviour. Complex viscosity and loss modulus can be predicted based on the chemical composition and temperature using polynomial models (R2> 98.00%).The authors thank the Universitat Politecnica de Valencia for funding the project "Seguridad alimentaria en la Region Suroeste de Burkina Faso. Capacitacion en manipulacion, transformacion y conservacion de alimentos locales, y contra la malnutricion infantil (BONALIMENT2013)", in the framework of the Program ADSIDEO of the Area de Cooperacio al Desenvolupament.Escriche Roberto, MI.; Oroian, M.; Visquert Fas, M.; Gras Romero, ML.; Vidal Brotons, DJ. (2016). Rheological properties of honey from Burkina Faso: loss modulus and complex viscosity modelling. International Journal of Food Properties. 19(11):2575-2586. doi:10.1080/10942912.2015.1136938S25752586191

Cellular and ultrastructural characterization of the grey-morph phenotype in southern right whales (Eubalaena australis)

Southern right whales (SRWs, Eubalena australis) are polymorphic for an X-linked pigmentation pattern known as grey morphism. Most SRWs have completely black skin with white patches on their bellies and occasionally on their backs; these patches remain white as the whale ages. Grey morphs (previously referred to as partial albinos) appear mostly white at birth, with a splattering of rounded black marks; but as the whales age, the white skin gradually changes to a brownish grey color. The cellular and developmental bases of grey morphism are not understood. Here we describe cellular and ultrastructural features of grey-morph skin in relation to that of normal, wild-type skin. Melanocytes were identified histologically and counted, and melanosomes were measured using transmission electron microscopy. Grey-morph skin had fewer melanocytes when compared to wild-type skin, suggesting reduced melanocyte survival, migration, or proliferation in these whales. Grey-morph melanocytes had smaller melanosomes relative to wild-type skin, normal transport of melanosomes to surrounding keratinocytes, and normal localization of melanin granules above the keratinocyte nuclei. These findings indicate that SRW grey-morph pigmentation patterns are caused by reduced numbers of melanocytes in the skin, as well as by reduced amounts of melanin production and/or reduced sizes of mature melanosomes. Grey morphism is distinct from piebaldism and albinism found in other species, which are genetic pigmentation conditions resulting from the local absence of melanocytes, or the inability to synthesize melanin, respectively

Declaración de Cancún: declaración internacional de Cancún sobre el derecho a la nutrición en los hospitales

La declaración de Cancún por el derecho humano de los enfermos a recibir una terapia nutricional oportuna y óptima en cualquier lugar donde se encuentren ha sido emitida por los Presidentes de las Sociedades y Asociaciones de Nutrición Clínica y Terapia Nutricional de América Latina y el Caribe, en el marco del XI Congreso de FELANPE/XV Congreso de AMAEE, en la Ciudad de Cancún Quintana Roo, México, el día 20 de mayo de 2008

Effect of Torrefaction on Water Vapor Adsorption Properties and Resistance to Microbial Degradation of Corn Stover

The equilibrium moisture content (EMC) of biomass affects transportation, storage, downstream feedstock processing, and the overall economy of biorenewables production. Torrefaction is a thermochemical process conducted in the temperature regime between 200 and 300 °C under an inert atmosphere that, among other benefits, aims to reduce the innate hydrophilicity and susceptibility to microbial degradation of biomass. The objective of this study was to examine water sorption properties of torrefied corn stover. The EMC of raw corn stover, along with corn stover thermally pretreated at three temperatures, was measured using the static gravimetric method at equilibrium relative humidity (ERH) and temperatures ranging from 10 to 98% and from 10 to 40 °C, respectively. Five isotherms were fitted to the experimental data to obtain the prediction equation that best describes the relationship between the ERH and the EMC of lignocellulosic biomass. Microbial degradation of the samples was tested at 97% ERH and 30 °C. Fiber analyses were conducted on all samples. In general, torrefied biomass showed an EMC lower than that of raw biomass, which implied an increase in hydrophobicity. The modified Oswin model performed best in describing the correlation between ERH and EMC. Corn stover torrefied at 250 and 300 °C had negligible dry matter mass loss due to microbial degradation. Fiber analysis showed a significant decrease in hemicellulose content with the increase in pretreatment temperature, which might be the reason for the hydrophobic nature of the torrefied biomass. The outcomes of this work can be used for torrefaction process optimization, and decision-making regarding raw and torrefied biomass storage and downstream processing

Tratamiento de reperfusión en el ictus isquémico agudo por disección arterial cervicocerebral: descripción de los resultados de un estudio nacional multicéntrico

Introducción El ictus isquémico (II) por disección arterial cervicocerebral (DAC) es una entidad infrecuente y existen pocos datos sobre el uso de terapias de reperfusión como la fibrinólisis intravenosa y la trombectomía mecánica. Se analizó el uso de dichas terapias en pacientes con II por DAC y se comparó con aquellos pacientes reperfundidos con II por otras causas. Método Estudio observacional retrospectivo multicéntrico de pacientes con II por DAC basado en el Registro Nacional de Ictus de la Sociedad Española de Neurología durante el periodo 2011-2019. Se realizaron análisis comparativos entre: a) pacientes con DAC tratados y no tratados con terapias de reperfusión y b) pacientes reperfundidos con II por DAC y pacientes reperfundidos con II por otras causas. Se incluyeron variables epidemiológicas, del ictus y resultados al alta y a los 3 meses. Resultados Un total de 21.037 pacientes con II fueron incluidos; 223 (1%) fueron por DAC y 68 (30%) recibieron tratamiento de reperfusión. El uso de tratamientos de reperfusión fue menor en los casos de DAC de arteria vertebral y mayor en los casos de oclusión carotídea. Los pacientes con II por DAC reperfundidos respecto a aquellos con II reperfundidos por otras causas fueron más jóvenes, la trombectomía mecánica se utilizó más y la fibrinólisis intravenosa menos. Las complicaciones hemorrágicas, la mortalidad y la autonomía a los 3 meses fueron similares. Conclusiones Las terapias de reperfusión se usan con frecuencia en los pacientes con II por DAC. Los resultados demuestran eficacia y seguridad y son equiparables a los pacientes tratados con terapias de reperfusión por II de otras causas. Introduction Ischaemic stroke (IS) due to cervical and cerebral artery dissection (CAD) is a rare entity, and few data are available on the use of such reperfusion therapies as intravenous fibrinolysis and mechanical thrombectomy in these patients. We analysed the use of these treatments in patients with IS due to CAD and compared them against patients receiving reperfusion treatment for IS of other aetiologies. Method We conducted an observational, retrospective, multicentre study of patients with IS due to CAD recorded in the National Stroke Registry of the Spanish Society of Neurology during the period 2011-2019. Comparative analyses were performed between: a) patients with CAD treated and not treated with reperfusion therapies and b) patients treated with reperfusion for IS due to CAD and patients treated with reperfusion for IS due to other causes. Epidemiological data, stroke variables, and outcomes at discharge and at 3 months were included in the analysis. Results The study included 21, 037 patients with IS: 223 (1%) had IS due to CAD, of whom 68 (30%) received reperfusion treatment. Reperfusion treatments were used less frequently in cases of vertebral artery dissection and more frequently in patients with carotid artery occlusion. Compared to patients with IS due to other causes, patients with CAD were younger, more frequently underwent mechanical thrombectomy, and less frequently received intravenous fibrinolysis. Rates of haemorrhagic complications, mortality, and independence at 3 months were similar in both groups. Conclusions Reperfusion therapy is frequently used in patients with IS due to CAD. The outcomes of these patients demonstrate the efficacy and safety of reperfusion treatments, and are comparable to the outcomes of patients with IS due to other aetiologies

Reperfusion treatment in acute ischaemic stroke due to cervical and cerebral artery dissection: results of a Spanish national multicentre study

Introducción: El ictus isquémico (II) por disección arterial cervicocerebral (DAC) es una entidad infrecuente y existen pocos datos sobre el uso de terapias de reperfusión como la fibrinólisis intravenosa y la trombectomía mecánica. Se analizó el uso de dichas terapias en pacientes con II por DAC y se comparó con aquellos pacientes reperfundidos con II por otras causas. Método: Estudio observacional retrospectivo multicéntrico de pacientes con II por DAC basado en el Registro Nacional de Ictus de la Sociedad Española de Neurología durante el periodo 2011-2019. Se realizaron análisis comparativos entre: a) pacientes con DAC tratados y no tratados con terapias de reperfusión y b) pacientes reperfundidos con II por DAC y pacientes reperfundidos con II por otras causas. Se incluyeron variables epidemiológicas, del ictus y resultados al alta y a los 3 meses. Resultados: Un total de 21.037 pacientes con II fueron incluidos; 223 (1%) fueron por DAC y 68 (30%) recibieron tratamiento de reperfusión. El uso de tratamientos de reperfusión fue menor en los casos de DAC de arteria vertebral y mayor en los casos de oclusión carotídea. Los pacientes con II por DAC reperfundidos respecto a aquellos con II reperfundidos por otras causas fueron más jóvenes, la trombectomía mecánica se utilizó más y la fibrinólisis intravenosa menos. Las complicaciones hemorrágicas, la mortalidad y la autonomía a los 3 meses fueron similares. Conclusiones: Las terapias de reperfusión se usan con frecuencia en los pacientes con II por DAC. Los resultados demuestran eficacia y seguridad y son equiparables a los pacientes tratados con terapias de reperfusión por II de otras causas.Introduction: Ischaemic stroke (IS) due to cervical and cerebral artery dissection (CAD) is a rare entity, and few data are available on the use of such reperfusion therapies as intravenous fibrinolysis and mechanical thrombectomy in these patients. We analysed the use of these treatments in patients with IS due to CAD and compared them against patients receiving reperfusion treatment for IS of other aetiologies. Method: We conducted an observational, retrospective, multicentre study of patients with IS due to CAD recorded in the National Stroke Registry of the Spanish Society of Neurology during the period 2011-2019. Comparative analyses were performed between: a) patients with CAD treated and not treated with reperfusion therapies and b) patients treated with reperfusion for IS due to CAD and patients treated with reperfusion for IS due to other causes. Epidemiological data, stroke variables, and outcomes at discharge and at 3 months were included in the analysis. Results: The study included 21,037 patients with IS: 223 (1%) had IS due to CAD, of whom 68 (30%) received reperfusion treatment. Reperfusion treatments were used less frequently in cases of vertebral artery dissection and more frequently in patients with carotid artery occlusion. Compared to patients with IS due to other causes, patients with CAD were younger, more frequently underwent mechanicalthrombectomy, and less frequently received intravenous fibri nolysis. Rates of haemorrhagic complications, mortality, and independence at 3 months were similar in both groups. Conclusions: Reperfusion therapy is frequently used in patients with IS due to CAD. The outcomes of these patients demonstrate the efficacy and safety of reperfusion treatments, and are comparable to the outcomes of patients with IS due to other aetiologie