155,673 research outputs found

    Desarrollo de papeles biocativos por injerto de moléculas específicas en celulosa

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    Tesis (DCI)--FCEFN-UNC, 2019En la presente tesis se presenta el desarrollo de papeles bioactivos con potencial aplicaci√≥n en el envasado activo de alimentos. Para tal fin, se propuso el injerto de eugenol, un compuesto de origen natural con propiedades antimicrobiana, antioxidante y repelente de insectos, en celulosa, utilizando √°cido policarbox√≠lico como agente ligante. Con el objetivo de evaluar la escalabilidad del proceso propuesto, se estudiaron distintas tecnolog√≠as de curado, tales como calentamiento por convecci√≥n, infrarrojo, microondas y conducci√≥n. En todos los casos, se analizaron la influencia de las variables operativas sobre el avance de la reacci√≥n y propiedades finales del papel preparado, utilizando un dise√Īo de experimentos Doehlert para elegir las experiencias a realizar, y analizando los resultados mediante metodolog√≠a de superficie de respuesta y an√°lisis estad√≠stico ANOVA. Se pudo comprobar que la reacci√≥n de injerto de eugenol en papel comercial se produjo con √©xito en todas las tecnolog√≠as estudiadas. Asimismo, se encontraron las condiciones √≥ptimas de reacci√≥n para cada una de las tecnolog√≠as, para lo cual se busc√≥ un compromiso entre el avance de la reacci√≥n y las propiedades finales del material (mec√°nicas y color). A partir de estas condiciones, se prepararon papeles y se realiz√≥ una caracterizaci√≥n m√°s espec√≠fica para su aplicaci√≥n como envase de alimentos comparando los papeles modificados con el papel virgen. Se analizaron las propiedades mec√°nicas por ensayo de tracci√≥n, rasgado y punzonado y se midi√≥ la absorci√≥n de agua y la capacidad de degradaci√≥n. Por otro lado, las propiedades bioactivas analizadas fueron la actividad antioxidante, antimicrobiana, repelente e insecticida de gorgojos (T. castaneum y R. dominica). Una vez probado que el papel modificado presenta buenas caracter√≠sticas f√≠sicas y bioactivas para su posible aplicaci√≥n en el envasado de alimentos, se realizaron prototipos de envasado para harina, como alimento representativo de alimentos derivados de cereales, susceptibles al ataque de plagas. En este estudio se analiz√≥ la migraci√≥n de reactivos, propiedades organol√©pticas y conservaci√≥n del alimento, arrojando resultados promisorios para la industria de envases de alimentos. Finalmente, se realiz√≥ una comparaci√≥n de las tecnolog√≠as de curado ensayadas, analizando diferentes aspectos como avance de reacci√≥n, propiedades finales, apariencia, tiempo de reacci√≥n, consumo de energ√≠a, entre otros, como as√≠ tambi√©n disponibilidad y uso de estas tecnolog√≠as a escala industrial, seleccionando la tecnolog√≠a de conducci√≥n como la m√°s adecuada para una propuesta de escalado industrial.Fil: Muratore, Florencia. Universidad Nacional de C√≥rdoba. Facultad de Ciencias Exactas, F√≠sicas y Naturales; Argentina.Fil: Muratore, Florencia. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Instituto de Investigaci√≥n y Desarrollo en Ingenier√≠a de Procesos y Qu√≠mica Aplicada; Argentina

    Application of lactic acid bacteria for the biopreservation of meat products: A systematic review

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    .The increasing concern of consumers about food quality and safety and their rejection of chemical additives has promoted the breakthrough of the biopreservation field and the development of studies on the use of beneficial bacteria and their metabolites as potential natural antimicrobials for shelf life extension and enhanced food safety. Control of foodborne pathogens in meat and meat products represents a serious challenge for the food industry which can be addressed through the intelligent use of bio-compounds or biopreservatives. This article aims to systematically review the available knowledge about biological strategies based on the use of lactic acid bacteria to control the proliferation of undesirable microorganisms in different meat products. The outcome of the literature search evidenced the potential of several strains of lactic acid bacteria and their purified or semi-purified antimicrobial metabolites as biopreservatives in meat products for achieving longer shelf life or inhibiting spoilage and pathogenic bacteria, especially when combined with other technologies to achieve a synergistic effect.S

    How Does Reciprocity Affect Undergraduate Student Orientation towards Stakeholders?

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    5987Nowadays, students are more aware of the impact of companies on their stakeholders and the need for properly handling their expectations to operationalize corporate social responsibility. Nevertheless, little is known about how certain individual traits may relate to their stance on the issue. This exploratory research contributes to stakeholder theory by analysing the e ect of the individual’s decision-making process, including the consideration of their social preferences, on their orientation toward stakeholder management. Here, we draw upon a theoretical model for resource-allocation decision-making consisting of reciprocal and non-reciprocal components. Our data, from undergraduate students enrolled in di erent degrees, were collected through a questionnaire and two social within-subject experiments (ultimatum and dictator games). Thus, our results show that the presence of a reciprocal component when decisions are made is positively linked to an instrumental orientation toward stakeholders. In addition, a greater non-reciprocal component in the decision-making process corresponds to a more normative orientation.S

    Analysis of reliable deployment of TDOA local positioning architectures

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    .Local Positioning Systems (LPS) are supposing an attractive research topic over the last few years. LPS are ad-hoc deployments of wireless sensor networks for particularly adapt to the environment characteristics in harsh environments. Among LPS, those based on temporal measurements stand out for their trade-off among accuracy, robustness and costs. But, regardless the LPS architecture considered, an optimization of the sensor distribution is required for achieving competitive results. Recent studies have shown that under optimized node distributions, time-based LPS cumulate the bigger error bounds due to synchronization errors. Consequently, asynchronous architectures such as Asynchronous Time Difference of Arrival (A-TDOA) have been recently proposed. However, the A-TDOA architecture supposes the concentration of the time measurement in a single clock of a coordinator sensor making this architecture less versatile. In this paper, we present an optimization methodology for overcoming the drawbacks of the A-TDOA architecture in nominal and failure conditions with regards to the synchronous TDOA. Results show that this optimization strategy allows the reduction of the uncertainties in the target location by 79% and 89.5% and the enhancement of the convergence properties by 86% and 33% of the A-TDOA architecture with regards to the TDOA synchronous architecture in two different application scenarios. In addition, maximum convergence points are more easily found in the A-TDOA in both configurations concluding the benefits of this architecture in LPS high-demanded applicationS

    Tense times for young migrants: temporality, life-course and immigration status

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    This article explores the intersection between immigration status, life-course and the experience of time. It looks at how time and life-course transitions are experienced by young people who are in constant encounter with the immigration regime in the UK. The encounters at this intersection produce a complex landscape for young people to navigate during their transitions to adulthood. What emerges from unpicking the relations of this messy and complex temporal-immigration status matrix, are distinct experiences of time and life-course transitions for young migrants. First, in dealing with the immigration regime young people are confined to a passive role of waiting that results in a sense of feeling stuck. Secondly, pre-18 young people experience a growing up too early and upon turning 18 and gaining legal independence, their situation paradoxically leads to practical dependence. And thirdly, the immigration status renewal system produces long-term uncertainty for young people’s futures

    The Idiosyncrasy of Involuntary Musical Imagery Repetition (IMIR) Experiences: The Role of Tempo and Lyrics

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    Involuntary musical imagery repetition (IMIR), colloquially known as ‚Äúearworms,‚ÄĚ is a form of musical imagery that arises involuntarily and repeatedly in the mind. A growing number of studies, based on retrospective reports, suggest that IMIR experiences are associated with certain musical features, such as fast tempo and the presence of lyrics, and with individual differences in music training and engagement. However, research to date has not directly assessed the effect of such musical features on IMIR and findings about individual differences in music training and engagement are mixed. Using a cross-sectional design (Study 1, n = 263), we examined IMIR content in terms of tempo (fast, slow) and presence of lyrics (instrumental, vocal), and IMIR characteristics (frequency, duration of episode and section) in relation to 1) the musical content (tempo and lyrics) individuals most commonly expose themselves to (music-listening habits), and 2) music training and engagement. We also used an experimental design (Study 2, n = 80) to test the effects of tempo (fast or slow) and the presence of lyrics (instrumental or vocal) on IMIR retrieval and duration. Results from Study 1 showed that the content of music that individuals are typically exposed to with regard to tempo and lyrics predicted and resembled their IMIR content, and that music engagement, but not music training, predicted IMIR frequency. Music training was, however, shown to predict the duration of IMIR episodes. In the experiment (Study 2), tempo did not predict IMIR retrieval, but the presence of lyrics influenced IMIR duration. Taken together, our findings suggest that IMIR is an idiosyncratic experience primed by the music-listening habits and music engagement of the individual

    Medicina personalizada en lactantes con cáncer: Estudio farmacogenético de polimorfismos relacionados con toxicidad y respuesta a la quimioterapia

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    Introducci√≥n La farmacogen√©tica es una herramienta de la ‚ÄúMedicina personalizada‚ÄĚ que contribuye a optimizar los tratamientos antineopl√°sicos, adapt√°ndolos a las caracter√≠sticas gen√©ticas particulares de cada individuo, maximizando su eficacia y minimizando su toxicidad. El lactante con c√°ncer es un paciente de particular vulnerabilidad y sus comorbilidades tiene una especial repercusi√≥n vital. El estudio farmacogen√©tico en esta poblaci√≥n resulta pionero y novedoso en nuestro medio. La identificaci√≥n de marcadores predictivos espec√≠ficos permitir√° individualizar m√°s la terap√©utica en esta poblaci√≥n tan fr√°gil y mejorar en consecuencia su calidad de vida y su pron√≥stico vital. Material y m√©todos Estudio de cohortes ambispectivo de pacientes oncol√≥gicos entre 1 y 18 meses de edad, receptores de quimioterapia en el Hospital La Fe de Valencia, en el periodo comprendido entre enero 2007 y agosto 2019. La parte retrospectiva comprende hasta diciembre 2015, el estudio prospectivo desde enero 2016 hasta agosto 2019. En primer lugar, se realiza un an√°lisis descriptivo de variables epidemiol√≥gicas, cl√≠nico/biol√≥gicas, terap√©uticas y pron√≥sticas de 72 pacientes con dichas caracter√≠sticas. Se describe la toxicidad derivada de sus 578 ciclos de quimioterapia (37 variables cl√≠nicas), el tiempo de seguimiento y su supervivencia (meses). En segundo lugar, se realiza un estudio anal√≠tico cuyo objetivo es correlacionar los polimorfismos gen√©ticos relacionados con la quimioterapia de 64 de los pacientes, la toxicidad grave secundaria al tratamiento (‚Č• grado 3 seg√ļn CTAE 4.0) y su supervivencia. El genotipado se realiza en el Centro Nacional de Genotipado (CEGEN) mediante la tecnolog√≠a MassArray (AgenaBioscience), previa configuraci√≥n de un panel farmacogen√©tico pedi√°trico en base a las evidencias recogidas en la base de datos PharmGKB, fichas t√©cnicas de los medicamentos y consorcios internacionales expertos. El an√°lisis estad√≠stico descriptivo se realiza con los programas Excel 2016 y R: las variables cualitativas con el recuento num√©rico (porcentaje) y las variables cuantitativas como mediana +/- rango intercuart√≠lico ante ausencia de normalidad en la distribuci√≥n de los datos (p <0,05, prueba de Kolmogorov-Smirnov). En el an√°lisis de supervivencia se utiliza el estimador Kaplan-Meier. El an√°lisis estad√≠stico anal√≠tico de correlaci√≥n entre polimorfismos y toxicidad se realiza mediante regresi√≥n log√≠stica penalizada por Elastic Net empleando R. El an√°lisis estad√≠stico anal√≠tico de correlaci√≥n entre polimorfismos y reca√≠da/muerte se realiza mediante regresi√≥n de Cox penalizada por Elastic Net. Resultados Las variables epidemiol√≥gicas, cl√≠nico/biol√≥gicas y terap√©uticas de los pacientes de la muestra son consecuentes con las descritas en la literatura del lactante con c√°ncer. Las neoplasias con mayor impacto negativo en la supervivencia son la leucemia mielobl√°stica aguda y los tumores del sistema nervioso central. La toxicidad m√°s prevalente es hematol√≥gica, digestiva e infecciosa. Existe correlaci√≥n entre la toxicidad grave secundaria a los quimioter√°picos en forma de anemia, neutropenia y/o trombopenia y 46 polimorfismos gen√©ticos diferentes. As√≠ mismo se encuentra asociaci√≥n estad√≠sticamente significativa entre la supervivencia global y la supervivencia libre de enfermedad y ciertos polimorfismos gen√©ticos (26 y 13 respectivamente). Los polimorfismos obtenidos pertenecen a genes encargados del transporte (6 genes) y metabolismo (17 genes) de los f√°rmacos, de la reparaci√≥n del material gen√©tico y la supresi√≥n tumoral (5 genes) y de otras funciones biol√≥gicas (4 genes). Conclusi√≥n Los resultados del presente estudio muestran correlaci√≥n estad√≠stica entre 46 polimorfismos de genes implicados en la cin√©tica farmacol√≥gica y la reparaci√≥n del material gen√©tico y la variabilidad en la toxicidad quimioter√°pica y supervivencia de pacientes lactantes con c√°ncer. En definitiva, aportaciones de la farmacogen√©tica que pueden contribuir a la optimizaci√≥n del tratamiento antineopl√°sico en esta poblaci√≥n particular y a la predicci√≥n de sus riesgos, de especial impacto en los supervivientes del c√°ncer infantil

    Uso de las histonas circulantes y sus modificaciones post-traduccionales como biomarcadores en sepsis y shock séptico

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    La sepsis es una afecci√≥n potencialmente mortal causada por una respuesta anormal del hu√©sped a una infecci√≥n, produciendo respuestas fisiol√≥gicas alteradas que da√Īan los propios tejidos del paciente y pueden provocar disfunci√≥n org√°nica e incluso la muerte. Asimismo, algunos pacientes s√©pticos progresan a shock s√©ptico, caracterizado por alteraciones circulatorias, celulares y metab√≥licas sustanciales que aumentan el riesgo de mortalidad. A pesar de que la sepsis se caracteriza por un mal funcionamiento del sistema inmunol√≥gico, lo que a su vez conduce a una respuesta inmune alterada e inmunosupresi√≥n, la alta complejidad de la fisiopatolog√≠a de la sepsis requiere una mayor investigaci√≥n para comprender las respuestas inmunes que ocurren durante la sepsis. Asimismo, las histonas extracelulares circulantes han ganado relevancia como mediadores citot√≥xicos en la sepsis, ya que act√ļan como patrones moleculares asociados a da√Īo, que inducen estr√©s oxidativo y activan el inflamasoma NLRP3. Estos mecanismos median la activaci√≥n de la piroptosis, un mecanismo de muerte celular programada que produce inflamaci√≥n mediante la expresi√≥n de IL-18, IL-1ő≤ and IL-1őĪ. Sin embargo, a pesar de la evidencia de activaci√≥n del inflamasoma en las c√©lulas inmunes durante la sepsis, se desconoce si las histonas extracelulares son capaces de activar los inflamasomas endoteliales y sus consecuencias. En este trabajo destacamos el papel previamente desconocido de las histonas extracelulares, mediando la activaci√≥n del inflamasoma NLRP3 y la piroptosis en las c√©lulas endoteliales, contribuyendo a la disfunci√≥n endotelial y la desregulaci√≥n de la respuesta inmune mediada por el endotelio. Asimismo, tambi√©n demostramos c√≥mo la acetilaci√≥n de histonas disminuye la activaci√≥n de la piroptosis. Adem√°s, demostramos que la piroptosis se produce en pacientes con shock s√©ptico y los niveles de histonas circulantes se correlacionan con la expresi√≥n de citoquinas proinflamatorias y citoquinas piropt√≥ticas, la liberaci√≥n de factores de adhesi√≥n endotelial y la gravedad de la enfermedad. Proponemos la piroptosis mediada por histonas como un nuevo objetivo para desarrollar intervenciones cl√≠nicas. De manera similar, hemos analizado las respuestas inmunorelacionadas que ocurren durante las primeras etapas de la sepsis con el objetivo de proporcionar nuevos datos comparando las cantidades de citoquinas, inmunomoduladores y otros mediadores endoteliales en pacientes cr√≠ticamente enfermos no s√©pticos, s√©pticos y de shock s√©ptico. Nuestro enfoque ayudar√° a caracterizar r√°pidamente las respuestas inmunes alteradas en pacientes s√©pticos y de shock s√©ptico ingresados en la Unidad de Cuidados Intensivos. Finalmente analizamos el papel de la metilaci√≥n del ADN en el control del sistema inmune s√©ptico. Nuestros resultados demostraron el papel central de la metilaci√≥n del ADN modulando la respuesta molecular en los pacientes de shock s√©ptico y contribuyendo a la inmunosupresi√≥n, a trav√©s de la alteraci√≥n de los patrones de metilaci√≥n de los promotores de IL-10 y TREM-2.Sepsis is a life-threatening condition caused by an abnormal host response to an infection that produce altered physiological responses which damages own tissues of the patient and can result in organ dysfunction and in some cases death. Likewise, a subset of septic patients progresses to septic shock, characterized by substantial circulatory, cellular and metabolic abnormalities, which substantially increase the risk of mortality. Sepsis is characterized by a malfunction of the immune system and it can lead to an altered immune response and immunosuppression. Moreover, the high complexity of the pathophysiology of sepsis requires of further investigation to characterize the immune responses in sepsis and septic shock. Likewise, circulating extracellular histones have gained relevance as cytotoxic mediators in sepsis pathophysiology, since they act as damage-associated molecular patterns, which induce oxidative stress and activate NLRP3 inflammasome. Subsequently, inflammasome mediates pyroptosis activation, a programmed cell death mechanism that produces inflammation through the release of IL-18, IL-1ő≤ and IL-1őĪ. However, despite inflammasome activation may occur in immune cells during sepsis, it is unknown if this process also takes place in endothelial cells and particularly whether extracellular histones are capable of activating endothelial inflammasomes and their consequences. In this work we highlight a previously unknown role for extracellular histones, that mediates the activation of NLRP3 inflammasome and pyroptosis in endothelial cells by contributing to endothelial dysfunction and the dysregulation of the immune response mediated by endothelium. Likewise, we demonstrated how histone acetylation decreases pyroptosis activation. Furthermore, we show how pyroptosis occurs in septic shock patients and how circulating histone levels correlate with the expression of pro-inflammatory and pyroptotic cytokines, the release of endothelial adhesion factors and septic shock severity. We propose histone-mediated pyroptosis as a new target to develop clinical interventions. Similarly, we have analyzed the immune-related responses occurring during the early stages of sepsis with the aim of providing new data by comparing the amounts of cytokines, immune modulators and other endothelial mediators in critically-ill non-septic patients, septic and septic shock patients. Our approach will help to rapidly characterize the altered immune responses in septic and septic shock patients admitted in the Intensive Care Unit. Finally, we also analyzed the role of DNA methylation in the control of septic immune system. Our results demonstrated the central role of DNA methylation modulating the molecular response in septic shock patients and contributing to immunosuppression, through the alteration of DNA methylation patterns of IL-10 and TREM2 promoters

    Rainfall Prediction: A Comparative Analysis of Modern Machine Learning Algorithms for Time-Series Forecasting

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    Rainfall forecasting has gained utmost research relevance in recent times due to its complexities and persistent applications such as flood forecasting and monitoring of pollutant concentration levels, among others. Existing models use complex statistical models that are often too costly, both computationally and budgetary, or are not applied to downstream applications. Therefore, approaches that use Machine Learning algorithms in conjunction with time-series data are being explored as an alternative to overcome these drawbacks. To this end, this study presents a comparative analysis using simplified rainfall estimation models based on conventional Machine Learning algorithms and Deep Learning architectures that are efficient for these downstream applications. Models based on LSTM, Stacked-LSTM, Bidirectional-LSTM Networks, XGBoost, and an ensemble of Gradient Boosting Regressor, Linear Support Vector Regression, and an Extra-trees Regressor were compared in the task of forecasting hourly rainfall volumes using time-series data. Climate data from 2000 to 2020 from five major cities in the United Kingdom were used. The evaluation metrics of Loss, Root Mean Squared Error, Mean Absolute Error, and Root Mean Squared Logarithmic Error were used to evaluate the models' performance. Results show that a Bidirectional-LSTM Network can be used as a rainfall forecast model with comparable performance to Stacked-LSTM Networks. Among all the models tested, the Stacked-LSTM Network with two hidden layers and the Bidirectional-LSTM Network performed best. This suggests that models based on LSTM-Networks with fewer hidden layers perform better for this approach; denoting its ability to be applied as an approach for budget-wise rainfall forecast applications
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