184 research outputs found

    Generación de electricidad en horas de punta a partir de la digestión anaeróbica de camalote

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    El presente trabajo tiene como objeto de presentar una propuesta novedosa y sustentable para la generación de energía eléctrica en el área metropolitana de Asunción basada en una fuente renovable de energía. Dicha generación se realizaría principalmente en horas de punta con el fin de reducir la potencia contratada por la ANDE en las usinas existentes y de esta forma disminuir costos y al mismo tiempo estabilizar las redes de transmisión y de distribución en la zona de Asunción. La electricidad se generaría en una planta térmica de ciclo combinado de 130 MW de potencia instalada utilizando como combustible biogás obtenido por medio de la digestión anaeróbica en biodigestores de plantas de camalote cultivadas en piletas a ser construidas en la orilla del río Paraguay frente al Jardín Botánico de Asunción. La principal ventaja para el aprovechamiento del camalote es su elevado índice de crecimiento, que es entre 100 y 500 g por día y por m2 según las condiciones ambientales, lo que permite que se duplique su masa vegetal cada 6 a 15 días. La relación entre carbono y nitrógeno, que se encuentra en su masa vegetal es óptima para la generación de biogás, cuyo poder calorífico de unos 6,4 kWh/m3 es suficientemente elevado para utilizarlo para la generación de calor y por ende también de electricidad en una planta térmica. Esa usina podría conectarse directamente al SIN a través de la Estación de Puerto Botánico mediante una línea de transmisión en 220 kV de 2 km cruzando el río Paraguay. Mediante este proyecto la ANDE podría ahorrar por año hasta US25,000,000enconceptodelacontratacioˊndepotenciaenlarepresadeItaipuˊ.Aunquedichoahorrosereducirıˊacadaan~ode3 25,000,000 en concepto de la contratación de potencia en la represa de Itaipú. Aunque dicho ahorro se reduciría cada año de 3% por el incremento de la demanda, la inversión de unos US 98,000,000 podría ser amortizada en un plazo de 15 años y tendrá un TIR del 5% y un VAN de US40,548,000TheobjectiveofthepresentpaperistopresentaninnovativeandsustainableproposalforgeneratingelectricityinthemetropolitanareaofAsuncion,thecapitalofParaguay,basedonarenewablesourceofenergy.ElectricitywouldmainlybegeneratedduringpeakhourswiththeaimofreducingpowercontractedbytheParaguayanElectricityAdministration(ANDE)fromexistinghydroelectricpowerplantsandthusreducecostsandstabilisetransmissionanddistributiongridsintheareaofAsuncion.Electricitywouldbegeneratedata130MWcombinedcyclethermalpowerplantusingbiogasasfuel,thisbeingobtainedbyanaerobicdigestionofwaterhyacinthscultivatedinpools,whichwouldbebuiltonthebanksoftheParaguayriveroppositeAsuncionsbotanicalgarden.Themainadvantageofusingwaterhyacinthsistheirhighgrowthrate,thisbeing100to500g/day/m2dependingonenvironmentalconditions,therebyallowingplantmasstodoubleevery6to15days.Additionally,carbontonitrogenratioinwaterhyacinthvegetalmassisoptimumforbiogasgeneration.About6.4kWh/m3biogascalorificvalueishighenoughtobeusedforproducingheatand,therefore,forgeneratingelectricityinathermalpowerplant.SuchpowerplantcouldbedirectlyconnectedtothenationalgridthroughthePuertoBotanictransformerstationbybuildinga2kmlong220kVtransmissionlinecrossingtheParaguayRiver.ThisprojectcouldsaveANDEupto25millionUS 40,548,000The objective of the present paper is to present an innovative and sustainable proposal for generating electricity in the metropolitan area of Asuncion, the capital of Paraguay, based on a renewable source of energy. Electricity would mainly be generated during peak hours with the aim of reducing power contracted by the Paraguayan Electricity Administration (ANDE) from existing hydroelectric power plants and thus reduce costs and stabilise transmission and distribution grids in the area of Asuncion. Electricity would be generated at a 130 MW combined cycle thermal power plant using biogas as fuel, this being obtained by anaerobic digestion of water hyacinths cultivated in pools, which would be built on the banks of the Paraguay river opposite Asuncion’s botanical garden. The main advantage of using water hyacinths is their high growth rate, this being 100 to 500 g/day/m2 depending on environmental conditions, thereby allowing plant mass to double every 6 to 15 days. Additionally, carbon to nitrogen ratio in water hyacinth vegetal mass is optimum for biogas generation. About 6.4 kWh/m3 biogas calorific value is high enough to be used for producing heat and, therefore, for generating electricity in a thermal power plant. Such power plant could be directly connected to the national grid through the Puerto Botanic transformer station by building a 2 km long 220 kV transmission line crossing the Paraguay River. This project could save ANDE up to 25 million US every year due to reduced contracted power at the Itaipu power plant. Although this reduction will decline by 3% each year due to increased electricity demand, the investment of around 98 million UScouldberepaidwithin15yearsandwouldhave5 could be repaid within 15 years and would have 5% IRR and US 40.5 million NPV

    Liver resection rate following downsizing chemotherapy with cetuximab in metastatic colorectal cancer: UK retrospective observational study

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    Aims The high objective response rate to cetuximab along with chemotherapy in patients with colorectal liver metastases makes it an effective downsizing protocol to facilitate surgery in those with initially unresectable disease. Adoption of this strategy has been variable in the UK. A retrospective observational study was conducted in 7 UK specialist liver surgical centres to describe the liver resection rate following a downsizing protocol of cetuximab and chemotherapy and to evaluate the quality and efficiency of processes by which the treatment was provided. Methods Data were collected in 2012 by reviewing medical records of patients with colorectal metastases confined to the liver, defined as unresectable without downsizing therapy at first review by a specialist Multi Disciplinary Team (MDT). Results Sixty patients were included; 29 (48%) underwent liver resection following cetuximab and chemotherapy. Of the 29, 17 (59% or 28% of all patients) achieved R0 resection and 7 (24% or 12% of all patients) R1 resection. All treated patients were KRAS wild-type. Conclusion In specialist liver surgical centres, where patients are evaluated for liver resection, optimal management by MDT using KRAS testing, cetuximab and chemotherapy results in a 28% R0 resection rate in patients with initially unresectable colorectal cancer liver metastases

    Aneurysm Ostium Angle: A Predictor of the Need for Stent as Assistance for Endovascular Aneurysm Coiling in Internal Carotid Artery Sidewall Aneurysms

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    BACKGROUND AND PURPOSE: There is no satisfactory parameter that can predict the need for assistant devices for endovascular aneurysm coiling. Our aim was to evaluate the utility of MOA as a predictor of the need for stent-assisted coiling in ICA sidewall aneurysms

    LipidXplorer: A Software for Consensual Cross-Platform Lipidomics

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    LipidXplorer is the open source software that supports the quantitative characterization of complex lipidomes by interpreting large datasets of shotgun mass spectra. LipidXplorer processes spectra acquired on any type of tandem mass spectrometers; it identifies and quantifies molecular species of any ionizable lipid class by considering any known or assumed molecular fragmentation pathway independently of any resource of reference mass spectra. It also supports any shotgun profiling routine, from high throughput top-down screening for molecular diagnostic and biomarker discovery to the targeted absolute quantification of low abundant lipid species. Full documentation on installation and operation of LipidXplorer, including tutorial, collection of spectra interpretation scripts, FAQ and user forum are available through the wiki site at: https://wiki.mpi-cbg.de/wiki/lipidx/index.php/Main_Page

    Lipidomic Analysis of Extracellular Vesicles from the Pathogenic Phase of Paracoccidioides brasiliensis

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    Background: Fungal extracellular vesicles are able to cross the cell wall and transport molecules that help in nutrient acquisition, cell defense, and modulation of the host defense machinery.Methodology/Principal Findings: Here we present a detailed lipidomic analysis of extracellular vesicles released by Paracoccidioides brasiliensis at the yeast pathogenic phase. We compared data of two representative isolates, Pb3 and Pb18, which have distinct virulence profiles and phylogenetic background. Vesicle lipids were fractionated into different classes and analyzed by either electrospray ionization- or gas chromatography-mass spectrometry. We found two species of monohexosylceramide and 33 phospholipid species, including phosphatidylcholine, phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Among the phospholipid-bound fatty acids in extracellular vesicles, C181 predominated in Pb3, whereas C18:2 prevailed in Pb18. the prevalent sterol in Pb3 and Pb18 vesicles was brassicasterol, followed by ergosterol and lanosterol. Inter-isolate differences in sterol composition were observed, and also between extracellular vesicles and whole cells.Conclusions/Significance: the extensive lipidomic analysis of extracellular vesicles from two P. brasiliensis isolates will help to understand the composition of these fungal components/organelles and will hopefully be useful to study their biogenesis and role in host-pathogen interactions.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)National Institutes of Health (NIH)Universidade Federal de São Paulo, UNIFESP, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniv Texas El Paso, Dept Biol Sci, Border Biomed Res Ctr, El Paso, TX 79968 USAUniversidade Federal de São Paulo, UNIFESP, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilFAPESP: 06/05095-6FAPESP: 07/04757-8FAPESP: 07/59768-4CNPq: 301666/2010-5National Institutes of Health (NIH): 5G12RR008124-16A1National Institutes of Health (NIH): 5G12RR008124-16A1S1National Institutes of Health (NIH): G12MD007592Web of Scienc

    Advances in structure elucidation of small molecules using mass spectrometry

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    The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

    Unravelling polar lipids dynamics during embryonic development of two sympatric brachyuran crabs (Carcinus maenas and Necora puber) using lipidomics

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    Embryogenesis is an important stage of marine invertebrates with bi-phasic life cycles, as it conditions their larval and adult life. Throughout embryogenesis, phospholipids (PL) play a key role as an energy source, as well as constituents of biological membranes. However, the dynamics of PL during embryogenesis in marine invertebrates is still poorly studied. The present work used a lipidomic approach to determine how polar lipid profiles shift during embryogenesis in two sympatric estuarine crabs, Carcinus maenas and Necora puber. The combination of thin layer chromatography, liquid chromatography – mass spectrometry and gas chromatography – mass spectrometry allowed us to achieve an unprecedented resolution on PL classes and molecular species present on newly extruded embryos (stage 1) and those near hatching (stage 3). Embryogenesis proved to be a dynamic process, with four PL classes being recorded in stage 1 embryos (68 molecular species in total) and seven PL classes at stage 3 embryos (98 molecular species in total). The low interspecific difference recorded in the lipidomic profiles of stage 1 embryos appears to indicate the existence of similar maternal investment. The same pattern was recorded for stage 3 embryos revealing a similar catabolism of embryonic resources during incubation for both crab species
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