4,296 research outputs found

    Factors affecting the production of putrescine from agmatine by Lactobacillus hilgardii X1B isolated from wine

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    Aims: To elucidate and characterize the metabolic putrescine synthesis pathway from agmatine by Lactobacillus hilgardii X1B. Methods and Results: The putrescine formation from agmatine by resting cells (the normal physiological state in wine) of lactic acid bacteria isolated from wine has been determined for the first time. Agmatine deiminase and N-carbamoylputrescine hydrolase enzymes, determined by HPLC and LC-Ion Trap Mass Spectrometry, carried out the putrescine synthesis from agmatine. The influence of pH, temperature, organic acids, amino acids, sugars and ethanol on the putrescine formation in wine was determined. Conclusions: Resting cells of Lact. hilgardii X 1B produce putrescine in wine. The putrescine production was carried out from agmatine through the agmatine deiminase system. Significance and Impact of the Study: These results have significance from two points of view, wine quality and toxicological and microbiological aspects, taking account that putrescine, which origin is still controversial, is quantitatively the main biogenic amine found in wine. © 2008 The Authors.Fil: Arena, Mario Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Landete, J. M.. Universidad de Valencia; EspañaFil: Manca, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Pardo, I.. Universidad de Valencia; EspañaFil: Ferrer, S.. Universidad de Valencia; Españ

    Los vaivenes de la fortuna

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    Fil: López de Vega, Laura.Fil: Granados de Arena, Dolores

    La vejez : a veces un mal peor que la muerte. Juvenal, Sátira X. 188-191 y 240-286

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    Fil: Granados de Arena, Dolores. Universidad Nacional de CuyoFil: López de Vega, Laura. Universidad Nacional de Cuy

    Apuleyo, metamorfosis IX : una seguidilla de adúlteros descubiertos

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    Fil: Granados de Arena, Dolores.Fil: López de Vega, Laura

    El heroismo de los asediados

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    Esta ponencia pretende centrar el relato en el heroísmo de pueblos asediados que por defender su suelo, no vacilaron en ofrendarse como víctimas. Se habla de Sagunto, Numancia, Thala y Masada, todos ellos relacionados con el mundo romano. Se trata de ver las actitudes en común que tuvieron estos pueblos, lo que hay de esencial en estos verdaderos suicidios colectivos.Fil: López de Vega, Laura. Universidad Nacional de Cuyo. Facultad de Filosofía y LetrasFil: Granados de Arena, Dolores. Universidad Nacional de Cuyo. Facultad de Filosofía y Letra

    Use of partial load operating conditions for latent thermal energy storage management

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    A proper management of thermal energy storage (TES) charging and discharging processes allows the final users to optimize the performance of TES systems. In this paper, an experimental research is carried out to study how the percentage of charge in a latent heat TES system (partial load operating conditions) influences the discharge process. Several charging and discharging processes were performed at a constant heat transfer fluid (HTF) mass flow rate of 0.5 kg/s and temperature of 155 °C and 105 °C, respectively. High density polyethylene (HDPE) with a total mass of 99.5 kg was used as phase change material (PCM) in a 0.154m3 storage tank based on the shelland-tube heat exchanger concept. Five different percentages of charge have been studied: 58 %, 73 %, 83 %, 92 %, and 97 % (baseline test). Results showed that by modifying the percentage of charge, the time required for the charging process was reduced between 97.2% and 68.8% in comparison to the baseline case. However, the energy accumulated was only reduced a maximum of 35.1% and a minimum of 5.2%, while the heat transfer rates during the first 60 min of discharge were reduced a maximum of 45.8% and a minimum of 6%. Therefore, partially charging the TES system not lower than 85% of its maximum energy capacity becomes a good option if the final application accepts a maximum decrease of discharging heat transfer rates of 10% if compared to the fully charged system.The work was partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement No. PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 657466 (INPATH-TES). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2017 FI_B1 00092). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Simone Arena would like to thank the Department of Mechanical, Chemical and Materials Engineering of the University of Cagliari for funding his research grant

    Comparative Analysis of Multiplicity Distributions in Inelastic Processes for Different Colliding Particles and Nuclei

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    Theoretical prediction of oscillations of cumulant moments of parton multiplicity distributions inside a jet supported by experimental data in some multiple production processes asks for analysis of the phenomenon for the whole set of available reactions. We have found out that the oscillations persist in any kind of processes and increase for particles with more complicated structure i.e. in the order of ee, eh, hh, hA, AA. The effect is not strongly dependent on the available phase space. Theoretical values of moments for quark and gluon jets up to 5th rank are shown. Zeros of the truncated generating function and singularities of the total generating function are discussed.Comment: revised version -- no changes in the text, corrected 3 references; 10 pages, 4 Postscript figure

    Opinions about Smoking, Secondhand Smoke Exposure, and Smoking Behaviors of Freshmen College Students

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    The purpose of this project was to assess first semester freshman college students’ opinions about smoking, secondhand smoke exposure, and smoking behaviors on a smoke-free campus. This research used an online cross-sectional survey. For two years, surveys were emailed via Zoomerang to all first semester freshmen students at Valparaiso University. Survey questions contained 60 forced-choice or open-ended options. Data were analyzed using descriptive statistics. A total of 630 students responded. Subjects were primarily female (58.4%) and Caucasian (84.9%). Twenty-five percent of the respondents reported being exposed to secondhand smoke in their environments. Twenty-nine percent were unaware that the campus is a smoke-free environment, 79% have seen smoking on campus, and 25% believed the smoke-free policy is not enforced. Seventy-seven percent of the respondents agreed or strongly agreed that the campus should be a smoke-free environment. Thirty-four percent of respondents admitted to smoking at some point in their lifetime. Fourteen percent (n=91) indicated that they had smoked during the previous 30 days, with only 28% of these identifying themselves as “current” smokers. The majority of the respondents supported a smoke-free environment and believed the current campus policy is enforced. Data from this study will add to the growing body of evidence about college students’ smoking behaviors

    Decomposizione della lettiera di quattro specie della macchia mediterranea: relazioni con alcune caratteristiche fogliarie con la qualità della lettiera

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    La velocità di decomposizione della lettiera di quattro specie tipiche della Macchia Mediterranea, Q. ilex, P. angustifolia, P. lentiscus e Cistus sp., è stata misurata dopo circa tre, sei e tredici mesi di incubazione in situ nella Riserva Naturale di Castel Volturno (Caserta). Sono state valutate le relazioni tra velocità di decomposizione e 1) indice di area fogliare specifica (SLA), 2) densità dei tessuti fogliari (LDMC), 3) grado di sclerofillia (GS), 4) contenuto in N, C e lignina e rapporto C/N della lettiera. Queste caratteristiche possono influenzare la colonizzazione e la utilizzazione della lettiera da parte dei microrganismi e, di conseguenza, la sua resistenza alla decomposizione. Dopo poco più di un anno la perdita di peso della lettiera era circa 50% in cisto, 41% in fillirea e 32% in leccio e lentisco. Nei primi tre mesi di incubazione, la velocità di decomposizione della lettiera è tanto maggiore quanto più alto è il valore di SLA e diminuisce con l’aumento del valore di LDMC e GS. La correlazione decomposizione - SLA e decomposizione - GS è statisticamente significativa solo se si esclude la fillirea che, ha caratteristiche fogliari simili a quelle di leccio e lentisco (spiccata sclerofillia) ma contenuto di lignina più basso non solo rispetto alle altre due specie sclerofille, ma anche rispetto al cisto (che ha caratteristiche mesofile). La velocità di decomposizione è correlata negativamente al contenuto di lignina e al rapporto lignina/N quando vengono considerate le quattro specie; se si considerano solo fillirea e cisto la correlazione diventa positiva. I risultati mostrano che la decomposizione della lettiera è la risultante degli effetti congiunti delle caratteristiche fogliari e della composizione chimica della lettiera
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