947 research outputs found

    Population dynamics of the zebra mussel (Dreissena polymorpha) in the Hudson River: settlement and post-settlement processes

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    Submitted in partial fulfillment of contract requirements with NOAA, Semi-Annual Report - October 2004,Report issued on: October 2004INHS Technical Report for submission to: National Oceanic and Atmospheric Administration (NOAA

    Multilevel variance components and brain volume mediation of life stress on post-traumatic stress disorder symptoms in children via regularization

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    Alterations of volume in brain regions of interest (ROIs) are associated with post-traumatic stress disorder (PTSD). Most of the extant neuroimaging research in PTSD has studied adults. The present study extends this research by using data from children (N=11,869, M age =9.92) from the ABCD study, a multisite longitudinal long-term study of brain development and childhood health in the U.S. Traumatic events (TEs) and PTSD symptoms were measured through the K- SADS for DSM-5. Values of brain ROIs were assessed using structural MRI measures. The unidirectional model was able to detect the small differences from site variance in sMRI mediators (subc: VS\u3c.009, SE\u3c.004; cort: VS\u3c.009, SE\u3c.004). Additive genetic factors explained 23.49% of the variance in TEs, 41.73% in subcortical and 19.94% in cortical mediators, and residual 21.01% in PTSD symptoms. Environmental factors explained most of the variance in TEs (C=.61, E=.16) and PTSD symptoms (resC=.19, resE=.21), as well as unique environmental factors in the cortical mediators (cort=.66). TEs highly influenced PTSD symptoms (.92). However, the indirect effect of TEs on PTSD symptoms through the mediation of volume in brain ROIs was small to non-influential at this age (subc=-.0003-.001, cort=-.001- .002). Several estimates of mediation effects were notably higher than most. Regularization via elastic net is implemented to train the mediation model to reduce bias and noise from overfitting, and to select the ROIs with mediation effects that explain the data with increased sparsity.https://scholarscompass.vcu.edu/gradposters/1102/thumbnail.jp

    Production of Bio-Based Chemicals and Polymers from Renewable Feedstocks: Bioprocesses Development

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    Tesis por compendio[ES] El aprovechamiento de subproductos para producir biocombustibles, energía y compuestos químicos básicos es cada vez más necesario en la situación actual de escasez de petróleo y preocupación por el medioambiente. Muchos compuestos que tradicionalmente han sido producidos a partir del petróleo pueden sintetizarse hoy día de forma biotecnológica empleando recursos renovables. En este contexto, los microorganismos pueden aprovecharse eficazmente como biocatalizadores para llevar a cabo estas transformaciones. Con este tipo de procesos se pueden aprovechar residuos o materias primas renovables para la obtención de productos de interés como bioplásticos de origen microbiano o productos químicos que pueden servir como monómeros para la síntesis de plásticos biodegradables u otro tipo de aplicaciones. La contaminación ambiental causada por los residuos de polímeros sintéticos no biodegradables es un problema en aumento debido a la estabilidad de los compuestos derivados de los combustibles fósiles. En contraste, los bioplásticos pueden obtenerse de fuentes renovables, lo que posibilita el desarrollo de procesos de producción sostenible. En este trabajo de investigación se han estudiado y desarrollado bioprocesos para la producción de polihidroxialkanoatos, 2,3-butanodiol y ácido D-láctico de forma sostenible empleando materias primas renovables como el suero lácteo de quesería, aceite de camelina, glicerina, fracción orgánica de residuos urbanos y residuos de naranja. La caracterización de las materias primas de partida se realizó mediante técnicas de análisis composicional, análisis en HPLC, cromatografía de gases y técnicas espectrofotométricas. Con estos resultados se hizo una selección de cepas bacterianas capaces de sintetizar los productos de interés a partir de los sustratos seleccionados. Una vez seleccionadas las cepas, el trabajo se centró en el desarrollo de los procesos para conseguir buenos rendimientos de fermentación y su escalado. Por lo tanto, este trabajo de investigación aporta conocimientos sobre la identificación y selección de biocatalizadores industriales para el uso de materias primas renovables y residuos industriales para la producción de productos químicos y polímeros de base biológica. Estos estudios allanan el camino para el futuro desarrollo de procesos biotecnológicos sostenibles en el marco de las biorrefinerías y de la bioeconomía circular.[CA] L'aprofitament de bioproductes per produir biocombustibles, energia i compostos químics bàsics és cada vegada més necessari en la situació actual d'escassetat de petroli i preocupació pel medi ambient. Molts compostos que tradicionalment s'han produït a partir de petroli es poden sintetitzar hui en dia biotecnològicament utilitzant recursos renovables. En aquest context, els microorganismes es poden utilitzar eficaçment com a biocatalitzadors per dur a terme aquestes transformacions. Amb aquest tipus de processos es poden utilitzar residus o matèries primeres renovables per obtenir productes d'interès com bioplàstics d'origen microbià o químics que puguen servir de monòmers per a la síntesi de plàstics biodegradables o altres aplicacions. La contaminació ambiental causada per residus de polímers sintètics no biodegradables és un problema creixent a causa de l'estabilitat dels compostos de combustibles fòssils. Per contra, els bioplàstics es poden obtenir a partir de fonts renovables, permetent el desenvolupament de processos productius sostenibles. En aquest treball de recerca s'han estudiat i desenvolupat bioprocessos per a la producció de polihidroxialcanoats, 2,3-butanodiol i àcid D-làctic de manera sostenible utilitzant matèries primeres renovables com sèrum de llet, oli de camelina, glicerina, fracció orgànica de residus urbans i residus de taronges. La caracterització de matèries primeres inicials es realitza mitjançant tècniques d'anàlisi composicional, anàlisi HPLC, cromatografia de gasos i tècniques espectrofotomètriques. Amb aquests resultats es crea una selecció de soques bacterianes capaç de sintetitzar els productes d'interès dels substrats seleccionats. Una vegada seleccionades les soques, el treball es va centrar en el desenvolupament dels processos per aconseguir uns bons rendiments de fermentació i el seu escalat. Per tant, aquest treball de recerca aporta coneixements sobre la identificació i selecció de biocatalitzadors industrials per a l'ús de matèries primeres renovables i residus industrials per a la producció de productes químics i polímers de base biològica. Aquests estudis amplien el coneixement per al futur desenvolupament de processos biotecnològics sostenibles en el marc de la biorefineria i la bioeconomia circular.[EN] The use of by-products to produce biofuels, energy and basic chemicals is increasingly necessary in the current situation of oil shortages and environmental concern. Many compounds that have traditionally been produced from oil can now be synthesised in a biotechnological way using renewable resources. In this context, microorganisms can be effectively used as biocatalysts to carry out these transformations. With this type of process, waste streams or renewable raw materials can be used to obtain products of interest such as bioplastics of microbial origin or chemical products that can serve as monomers for the synthesis of biodegradable plastics or other types of applications. Environmental pollution caused by non-biodegradable synthetic polymer waste is a growing problem due to the stability of compounds derived from fossil fuels. In contrast, bioplastics can be obtained from renewable sources, which enables the development of sustainable production processes. In this research work, bioprocesses for the production of polyhydroxyalkanoates, 2,3-butanediol and D-lactic acid using renewable raw materials such as cheese whey, camelina oil, glycerine, organic waste and orange waste were studied and developed. The characterisation of the raw materials was carried out using compositional analysis, HPLC analysis, gas chromatography and spectrophotometric techniques, among others. With these results, a selection of bacterial strains capable of synthesising the products of interest from the selected substrates was made. Once the strains were selected, the work was focused on process development in order to optimize fermentation yields and scale-up. Therefore, this research work provides knowledge on the identification and selection of industrial biocatalysts for the use of renewable feedstocks and industrial wastes for the production of bio-based chemicals and polymers. These studies pave the way for further development of sustainable biotechnological processes in the framework of biorefineries and circular bioeconomy.Bustamante Jaramillo, DA. (2021). Production of Bio-Based Chemicals and Polymers from Renewable Feedstocks: Bioprocesses Development [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/175819TESISCompendi

    Camelina Oil as a Promising Substrate for mcl-PHA Production in Pseudomonas sp. Cultures

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    Background and objective: Polyhydroxyalkanoates are biodegradable polyesters synthesized by some prokaryotic organisms from renewable sources. Medium-chain-length Polyhydroxyalkanoates show interesting properties as elastic and adhesive specialty polymers. Medium-chain-length Polyhydroxyalkanoates producers such as Pseudomonas sp. have demonstrated high yields on fats and oils. Camelina sativa is non-food chain competing crop, whose seed contain about 43% (w w-1) oil in dry matter with about 90% (w w-1) of unsaturated fatty acids. Camelina oil was for the first time tested for the production of medium-chainlength Polyhydroxyalkanoates by different Pseudomonas strains.Material and methods: The production of Polyhydroxyalkanoate was evaluated in a nitrogen-limited minimal medium supplemented with crude Camelina oil or saponified oil to compare the production capability of Pseudomonas sp. strains. A phosphates-limited medium was used to optimize polyhydroxyalkanoate production in fed-batch assays. Experiments were carried out by duplicates.Results and conclusion: Pseudomonas resinovorans was used for direct fermentation of Camelina oil without prior hydrolysis. A first approach to process development in bioreactor has provided up to 40% (w w-1) polymer content, matching highest medium-chain-length polyhydroxyalkanoates titer reported from plant oils (13.2 g l-1). Camelina oil was shown to be a suitable substrate for production of medium-chain-length polyhydroxyalkanoates. This non-food vegetable oil gave good results for Pseudomonas resinovorans DSM 21078 without any pre-treatment.Conflict of interest: The authors declare no conflict of interest

    Encuestas muestran una pequeña parte del contexto. Son válidas las críticas

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    Las encuestas sobre intención de voto siempre estarán acompañadas de un manto de duda. Pues, más allá de los asuntos técnicos de la estadística, las muestras y las metodologías utilizadas, las encuestas, desde la teoría de los partidos políticos, son instrumentos de deformación de la opinión pública. En ese sentido, tendríamos que afirmar que toda encuesta tiene un propósito político. En este orden de ideas, las encuestas deforman la opinión pública porque solo evidencian una porción muy reducida de la expresión electoral. Son solo una muestra de un momento específico, dejando por fuera la motivación electoral y, para el caso de nuestro país, las estructuras electorales o los llamados votos de maquinaria. No obstante, las encuestas son importantes en la medida que, cuando están segmentadas por zonas, pueden llegar a evidenciar el comportamiento regional de la opinión. Por Pedro Piedrahíta. PhD en Derecho. Docente del programa de Ciencia Política, U. de Medellín

    Solar and lighting transmission in complex fenestration systems with perforated solar protection systems

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    Santiago de Chile is a city with a semi-arid climate, with prolonged periods of high temperature and solar radiation. In recent years, in this city, office buildings have been built with high window to wall ratio (WWR) facades. 65% of the office buildings built in the period 2005-2014 have a WWR higher than 60%. Only 5% of these buildings showed an efficient glazed façade solar protection device. One of these systems corresponds to an exterior textile solar protection. This type of systems, together with the perforated screens, could be effective solutions for the solar protection of glazed facades, reducing the cooling energy consumption of buildings, without risking the visual comfort of the occupants. The objective of this research is to evaluate the solar transmission and lighting of seven perforated solar protection systems. Three of these systems correspond to external textile solar protections, and the remaining four are perforated metallic screens. The evaluation was carried out by applying an experimental protocol in two different calorimeters that simulate an office space. In one of the calorimeters, the solar protection systems are installed while the other is used as a reference without any solar protection system. Measurements were made with illuminance sensors and pyranometers. The horizontal illuminance sensors from Konica Minolta (T10) were installed outdoor and at different points inside the calorimeters. Near the facade, vertical indoor and outdoor pyrometers were installed (Kipp Zonnen, CMP11 and Sp Lite 2). The measurements on the north facade are made in summer on clear days. The measurements showed a reduction in solar transmission of 82.1% (metallic screen, 40% drilling) to 94.7% (cloth, 3% drilling) and from 70.8% to 95.4% in the transmission of lighting respectively

    Animal models of chronic pain. Are naturally occurring diseases a potential model for translational research?

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    Despite the vast amount of molecular data obtained from classical pain studies, there is an ongoing translational pain model crisis reflected by the reduced amount of new effective and safe compounds developed to treat chronic pain in humans. Naturally occurring chronic pain in animals may offer some advantages over induced models of chronic pain, including a natural development of the condition that induces pain, the heterogenicity of the population that affects, and the chronologic age in which they develop, among others. The identification and study of naturally occurring painful diseases that resemble a particular chronic painful condition in humans has been proposed as a potential tool to investigate the molecular mechanisms and thus, accelerating drug development at the preclinical and clinical level. Currently, certain types of chronic pain in companion and large animals have gained attention as potential translational models of chronic pain. Examples of these include canine and feline osteoarthritis, neoplastic diseases as osteosarcoma and bovine and equine lameness. The present review describes the limitations of animal models of chronic pain and briefly enters in how naturally occurring pain models could represent a translational approach to chronic pain

    Mortality determinants of children with cancer and febrile neutropenia

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    Objetivo: Identificar los determinantes de la mortalidad del niño con cáncer y neutropenia febril. Métodos: se realizó un estudio prospectivo observacional, de pacientes menores de 19 años con diagnóstico de neutropenia febril atendidos en el servicio de pediatría del Instituto Nacional de Cancerología y se evaluaron las variables que impactaron sobre los desenlaces desfavorables como la muerte y el ingreso a la Unidad de Cuidado Intensivo Pediátrico, además de las variables demográficas. Resultados: se evaluaron 175 episodios de neutropenia febril en 102 pacientes. Las patologías oncológicas que más registraron episodios fueron las leucemia linfoblástica agudas y los Linfomas Linfoblasticos. La celulitis y mucositis fueron nuestros principales focos infecciosos. La mortalidad por neutropenia febril fue del 2.8% y la probabilidad de muerte se relacionó positivamente con el crecimiento de Gram negativos en los hemocultivos. Conclusiones: La neutropenia febril sigue siendo una causa relevante de mortalidad en el paciente pediátrico con cáncer y el crecimiento de Gram negativos en los hemocultivos se relaciona en forma estadísticamente significativa con la posibilidad de muerte por esta entidad.Instituto Nacional de CancerologíaAim: To identify determinants of mortality for children with cancer and febrile neutropenia. Methods: we conduced a prospective observational study of patients under 19 years with diagnosis of febrile neutropenia treated in the National Cancer Institute from Colombia and we analyzed the variables that impacted on adverse outcomes such death and need of Pediatric Intensive Care Unit, in addition to demographic variables. Results: 175 episodes of febrile neutropenia were evaluated in 102 patients. Oncological pathologies recorded more episodes were acute lymphoblastic leukemia and lymphoblastic lymphoma. Cellulitis and mucositis were our main sources of infection. The mortality from febrile neutropenia was 2.8% and the probability of death was positively related to the growth of Gram negative blood cultures. Conclusions: Febrile neutropenia remains a major cause of mortality in pediatric patients with cancer and the growth of Gram negative blood cultures were statistically significantly associated with the likelihood of death by this entity
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