142,523 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

    A new index of resilience applicable to external pulse-disturbances that considers the recovery of communities in the short term

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    .Resilience is a key concept in the study of the recovery of ecosystems affected by disturbances. Currently, there are numerous indices to measure resilience, but many of them do not show the accuracy of the resilience value or the behaviour of ecological parameters in the face of disturbances. New approaches and technologies enable large amounts of information to be obtained, facilitating the proposal of new resilience indices that work consistently and intuitively for a wide variety of ecological response variables under different scenarios after pulse-disturbances. In this study, we propose and verify a new resilience index, comparing its performance with others previously published. We validated the performance of the new index using real data based on field measurements of changes in soil bacterial OTUs diversity and abundance after a wildfire. The new resilience index provided an automatic and robust functional classification of the behaviour of ecosystems after disturbances, supported by a bootstrap analysis. We identified 5 scenarios of ecosystem resilience performance according to their behaviour after a pulse-disturbance: resilient, non-resilient, recovering, rebound, and continuing.S

    Identification of Hindbrain Neural Substrates for Motor Initiation in the hatchling Xenopus laevis Tadpole

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    Animal survival profoundly depends on the ability to detect stimuli in the environment, process them and respond accordingly. In this respect, motor responses to a sensory stimulation evolved into a variety of coordinated movements, which involve the control of brain centres over spinal locomotor circuits. The hatchling Xenopus tadpole, even in its embryonic stage, is able to detect external sensory information and to swim away if the stimulus is considered noxious. To do so, the tadpole relies on well-known ascending sensory pathway, which carries the sensory information to the brain. When the stimulus is strong enough, descending interneurons are activated, leading to the excitation of spinal CPG neurons, which causes the undulatory movement of swimming. However, the activation of descending interneurons that marks the initiation of motor response appears after a long delay from the sensory stimulation. Furthermore, the long-latency response is variable in time, as observed in the slow-summating excitation measured in descending interneurons. These two features, i.e. long-latency and variability, cannot be explained by the firing time and pattern of the ascending sensory pathway of the Xenopus tadpole. Therefore, a novel neuronal population has been proposed to lie in the hindbrain of the tadpole, and being able to 'hold' the sensory information, thus accounting for the long and variable delay of swim initiation. In this work, the role of the hindbrain in the maintenance of the long and variable response to trunk skin stimulation is investigated in the Xenopustadpole at developmental stage 37/38. A multifaceted approach has been used to unravel the neuronal mechanisms underlying the delayed motor response, including behavioural experiments, electrophysiology analysis of fictive swimming, hindbrain extracellular recordings and imaging experiments. Two novel neuronal populations have been identified in the tadpole's hindbrain, which exhibit activation patterns compatible with the role of delaying the excitation of the spinal locomotor circuit. Future work on cellular properties and synaptic connections of these newly discovered populations might shed light on the mechanism of descending control active at embryonic stage. Identifying supraspinal neuronal populations in an embryonic organism could aid in understanding mechanisms of descending motor control in more complex vertebrates

    Bioinformatic characterization of a triacylglycerol lipase produced by Aspergillus flavus isolated from the decaying seed of Cucumeropsis mannii

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    Lipases are enzymes of industrial importance responsible for the hydrolysis of ester bonds of triglycerides. A lipolytic fungus was isolated and subsequently identified based on the ITS sequence analysis as putative Aspergillus flavus with accession number LC424503. The gene coding for extracellular triacylglycerol lipase was isolated from Aspergillus flavus species, sequenced, and characterised using bioinformatics tools. An open reading frame of 420 amino acid sequence was obtained and designated as Aspergillus flavus lipase (AFL) sequence. Alignment of the amino acid sequence with other lipases revealed the presence GHSLG sequence which is the lipase consensus sequence Gly-X1-Ser-X2-Gly indicating that it a classical lipase. A catalytic active site lid domain composed of TYITDTIIDLS amino acids sequence was also revealed. This lid protects the active site, control the catalytic activity and substrate selectivity in lipases. The 3-Dimensional structural model shared 34.08% sequence identity with a lipase from Yarrowia lipolytica covering 272 amino acid residues of the template model. A search of the lipase engineering database using AFL sequence revealed that it belongs to the class GX-lipase, superfamily abH23 and homologous family abH23.02, molecular weight and isoelectric point values of 46.95‚ÄČKDa and 5.7, respectively. N-glycosylation sites were predicted at residues 164, 236 and 333, with potentials of 0.7250, 0.7037 and 0.7048, respectively. O-glycosylation sites were predicted at residues 355, 358, 360 and 366. A signal sequence of 37 amino acids was revealed at the N-terminal of the polypeptide. This is a short peptide sequence that marks a protein for transport across the cell membrane and indicates that AFL is an extracellular lipase. The findings on the structural and molecular properties of Aspergillus flavus lipase in this work will be crucial in future studies aiming at engineering the enzyme for biotechnology applications

    The JCMT BISTRO Survey: Multi-wavelength polarimetry of bright regions in NGC 2071 in the far-infrared/submillimetre range, with POL-2 and HAWC+

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    Polarized dust emission is a key tracer in the study of interstellar medium and of star formation. The observed polarization, however, is a product of magnetic field structure, dust grain properties and grain alignment efficiency, as well as their variations in the line of sight, making it difficult to interpret polarization unambiguously. The comparison of polarimetry at multiple wavelengths is a possible way of mitigating this problem. We use data from HAWC+/SOFIA and from SCUBA-2/POL-2 (from the BISTRO survey) to analyse the NGC 2071 molecular cloud at 154, 214 and 850 őľm. The polarization angle changes significantly with wavelength over part of NGC 2071, suggesting a change in magnetic field morphology on the line of sight as each wavelength best traces different dust populations. Other possible explanations are the existence of more than one polarization mechanism in the cloud or scattering from very large grains. The observed change of polarization fraction with wavelength, and the 214-to-154 őľm polarization ratio in particular, are difficult to reproduce with current dust models under the assumption of uniform alignment efficiency. We also show that the standard procedure of using monochromatic intensity as a proxy for column density may produce spurious results at HAWC+ wavelengths. Using both long-wavelength (POL-2, 850 őľm) and short-wavelength (HAWC+, ‚Č≤200őľm) polarimetry is key in obtaining these results. This study clearly shows the importance of multi-wavelength polarimetry at submillimeter bands to understand the dust properties of molecular clouds and the relationship between magnetic field and star formation

    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

    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
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