1,591 research outputs found

    Effect of row orientation on soil water content and vine water status on a Cabernet franc vineyard in Madrid, spain

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    The aim of this study was to evaluate the effects of row orien¬tation on vine and soil water status in an irrigated vineyard. The trial was developed during 2006, 2007 and 2008, in the South East region of Madrid (Spain) on 5-year old Cabernet franc grapevines (Vitis vinifera L.) grafted onto 140Ru. Plant spacing was 2.5 m x 1.5 m and vines were trained to a VSP. Four orientations were stu¬died: North-South (N-S), East-West (E-W), Northeast-Southwest (N+45) and North-South +20o (N+20). Irrigation (0.4•ET0) started when shoot growth stopped. Soil water availability was measured using a TDR technique with forty buried probes. Row orientation did not have any effect on water consumption in the vineyard. At maturity, leaf water potential was measured at predawn, early mor¬ning, midday and 14:00 solar time, on both canopy sides - sun and shade – ; the early morning measurement was the one that better differentiated treatments. Leaf water potential was a good indica¬tor of plant water status. Differences between (N-S and E-W) and (N+20 and N+45) treatments were obtained both on sun and shade canopy sides, N+20 and N+45 having lower leaf water potentials then drier leaves. The water stress integral shows that N-S and E-W reach the end of maturation with a greater level of hydration than N+45 and N+20. As a whole, N+45 and N+20 orientations, without affecting too much the soil available water content, induce regularly more water stress to the vine at some periods, probably due to an higher sunlight interception in early morning which makes water limitation for the vine more early and thus more severe during the day

    The Bad, the Good, and the Ugly about Oxidative Stress

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    Alzheimer's disease (AD), Parkinson's disease (PD), and cancer (e.g., leukemia) are the most devastating disorders affecting millions of people worldwide. Except for some kind of cancers, no effective and/or definitive therapeutic treatment aimed to reduce or to retard the clinic and pathologic symptoms induced by AD and PD is presently available. Therefore, it is urgently needed to understand the molecular basis of these disorders. Since oxidative stress (OS) is an important etiologic factor of the pathologic process of AD, PD, and cancer, understanding how intracellular signaling pathways respond to OS will have a significant implication in the therapy of these diseases. Here, we propose a model of minimal completeness of cell death signaling induced by OS as a mechanistic explanation of neuronal and cancer cell demise. This mechanism might provide the basis for therapeutic design strategies. Finally, we will attempt to associate PD, cancer, and OS. This paper critically analyzes the evidence that support the “oxidative stress model” in neurodegeneration and cancer

    Biodegradation of alkyl branched aromatic alkanoic naphthenic acids by Pseudomonas putida KT2440

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    The majority of the world's crude oil reserves consist of highly biodegraded heavy and super heavy crude oils and oil sands that have not yet been fully exploited. These vast resources contain complex mixtures of carboxylic acids known as naphthenic acids (NAs). NAs cause major environmental and economic problems, as they are recalcitrant, corrosive and toxic. Although aromatic acids make up a small proportion of most NA mixtures, they have demonstrable toxicities to some organisms (e.g. some bacteria and algae) and ideally need to be removed or reduced by remediation. The present study analysed the ability of Pseudomonas putida KT2440 to degrade highly recalcitrant aromatic acids, as exemplified by the alkyl phenylalkanoic acid (4'-t-butylphenyl)-4-butanoic acid (t-BPBA) and the more degradable (4'-n-butylphenyl)-4-butanoic acid (n-BPBA). n-BPBA was completely metabolized after 14 days, with the production of a persistent metabolite identified as (4'-n-butylphenyl)ethanoic acid (BPEA) which resulted from removal of two carbon atoms from the carboxyl side chain (beta-oxidation) as observed previously with a mixed consortium. However, when n-BPBA concentration was increased two-fold, degradation decreased by 56% with a concomitant six-fold decrease in cell numbers, suggesting that at greater concentrations, n-BPBA may be toxic to P. putida KT2440. In contrast, P. putida KT2440 was unable to degrade the highly recalcitrant t-BPBA even after 49 days. These findings have implications for NA bioremediation in the environment. © 2011

    X-ray scatter measurements from thermally slumped thin glass substrates for the HEFT hard x-ray telescopes

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    We have performed x-ray specular reflectivity and scattering measurements of thermally slumped glass substrates on x-ray diffractometers utilizing a rotating anode x-ray source at the Danish Space Research Institute (DSRI) and synchrotron radiation at the European Synchrotron Radiation Facility (ESRF) optics Bending Magnet beamline. In addition, we tested depth graded W/Si multilayer-coated slumped glass using x-ray specular reflectivity measurements at 8.048 keV and 28 keV and energy-dispersive measurements in the 20-50 keV rang at a double-axis diffractometer at the Orsted Laboratory, University of Copenhagen. The thermally slumped glass substrates will be used to fabricate the hard x-ray grazing incidence optics for the High-Energy Focusing Telescope. We compared the measurements to the SODART- mirrors from the SRG telescope mission program. The surface scatter measurement of the thermally slumped glass substrates yields Half Power Diameters (HPD's) of single- bounce mirrors of full-illuminated lengths of ~ 40 arcseconds for typical substrates and as low as ~ 10 arcseconds for the best substrates, whereas the SODART mirrors yields HPD's of ~ 80 arcseconds with very little variation. Both free-standing glass substrates and prototype mounted and multilayer-coated optics were tested. The result demonstrate that the surface scatter contribution, plus any contribution from the mounting procedure, to the Half Power Diameter from a telescope using the slumped glass optics will be in the subarcminute range.In addition we measured low surface microroughness, yielding high reflectivity, from the glass substrates, as well as from the depth graded W/Si multilayer-coated glass glass (interfacial width 4.2 Å)

    Hard x-ray characterization of a HEFT single-reflection prototype

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    We have measured the hard X-ray reflectivity and imaging performance from depth graded W/Si multilayer coated mirror segments mounted in a single reflection cylindrical prototype for the hard X-ray telescopes to be flown on the High Energy Focusing Telescope (HEFT) balloon mission. Data have been obtained in the energy range from 18 - 170 keV at the European Synchrotron Radiation Facility and at the Danish Space Research Institute at 8 keV. The modeling of the reflectivity data demonstrate that the multilayer structure can be well described by the intended power law distribution of the bilayer thicknesses optimized for the telescope performance and we find that all the data is consistent with an interfacial width of 4.5 Å. We have also demonstrated that the required 5% uniformity of the coatings is obtained over the mirror surface and we have shown that it is feasible to use similar W/Si coatings for much higher energies than the nominal energy range of HEFT leading the way for designing Gamma-ray telescopes for future astronomical applications. Finally we have demonstrate 35 arcsecond Half Power Diameter imaging performance of the one bounce prototype throughout the energy range of the HEFT telescopes

    Flavonoid metabolites reduce tumor necrosis factor-α secretion to a greater extent than their precursor compounds in human THP-1 monocytes.

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    Scope - Flavonoids are generally studied in vitro, in isolation, and as unmetabolized precursor structures. However, in the habitual diet, multiple flavonoids are consumed together and found present in the circulation as complex mixtures of metabolites. Using a unique study design, we investigated the potential for singular or additive anti-inflammatory effects of flavonoid metabolites relative to their precursor structures. Methods and results - Six flavonoids, 14 flavonoid metabolites, and 29 combinations of flavonoids and their metabolites (0.1–10 μM) were screened for their ability to reduce LPS-induced tumor necrosis factor-α (TNF-α) secretion in THP-1 monocytes. One micromolar peonidin-3-glucoside, cyanidin-3-glucoside, and the metabolites isovanillic acid (IVA), IVA-glucuronide, vanillic acid-glucuronide, protocatechuic acid-3-sulfate, and benzoic acid-sulfate significantly reduced TNF-α secretion when in isolation, while there was no effect on TNF-α mRNA expression. Four combinations of metabolites that included 4-hydroxybenzoic acid (4HBA) and/or protocatechuic acid also significantly reduced TNF-α secretion to a greater extent than the precursors or metabolites alone. The effects on LPS-induced IL-1β and IL-10 secretion and mRNA expression were also examined. 4HBA significantly reduced IL-1β secretion but none of the flavonoids or metabolites significantly modified IL-10 secretion. Conclusion - This study provides novel evidence suggesting flavonoid bioactivity results from cumulative or additive effects of circulating metabolites

    Discursos sobre a migração venezuelana no Peru: trabalho e características do emprego

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    Within the Critical Discourse Analysis framework and through micro-level linguistic tools, we analyze 64 interviews with Peruvians from Lima and Arequipa about the Venezuelan population recently arrived in Peru with the objective of identifying the main representations on labor and working characteristics of migrants. To do so, we interview two groups of people according to their occupation: basic occupation (mainly services) and non-basic occupation (mainly professionals). This criterion is relevant to identify differences in the discourses of the interviewees. Results point out some positive aspects of migrants, such as being hardworking, friendly and attentive to clients, prepared and educated; on the other hand, they also signal negative features, such as stating that they take work away from locals or describing them as lazy, since it is considered that in Venezuela they were not used to work. In the analysis, we observe how these discourses are supported by the contrast with representations of identity within Peruvians, conceived as hard-working and striving. In addition, we note the presence of ideological dilemmas, referring to tensions between contradictory discourses in the same group of interviewees or in the same person.En el marco del Análisis Crítico del Discurso y mediante herramientas lingüísticas a nivel micro, se analizan 64 entrevistas a población peruana de Lima y Arequipa sobre la comunidad venezolana en el Perú. El objetivo de la investigación es identificar las principales representaciones que se construyen sobre los migrantes en torno al trabajo y las características laborales. Para ello, se entrevistan grupos de ambas ciudades caracterizados por dos tipos de ocupación: básica (servicios y atención al cliente) y no básica (principalmente profesionales). Este criterio resulta relevante para identificar diferencias en los discursos de los entrevistados. Los resultados señalan aspectos positivos de los migrantes, como ser trabajadores, amables y atentos, preparados y educados; por otro lado, apuntan a rasgos negativos, como afirmar que quitan trabajo a los locales o, por el contrario, describirlos como flojos, pues se considera que en Venezuela no tenían costumbre de trabajar. En el análisis, se observa cómo los discursos contrastan con las representaciones acerca de la identidad de los peruanos, concebidos como trabajadores y esforzados. Además, se identifican dilemas ideológicos, referidos a tensiones entre discursos contradictorios en un mismo grupo o entrevistado.No âmbito da Análise do Discurso Crítico e utilizando ferramentas linguísticas de nível micro, analisamos 64 entrevistas com a população peruana em Lima e Arequipa sobre a comunidade venezuelana no Peru, com o objetivo de identificar as principais representações que são construídas sobre os migrantes em termos de trabalho e características do emprego. Assim, entrevistamos grupos caracterizados por dois tipos de ocupação: básica (serviços e atendimento ao cliente) e não-básica (principalmente profissionais). Este critério é relevante para identificar as diferenças nos discursos dos entrevistados. Os resultados apontam para aspectos positivos dos migrantes, como ser trabalhador, amigável e atencioso, preparado e educado; por outro lado, apontam para traços negativos, como afirmar que tiram trabalho dos locais ou descrevê-los como preguiçosos, pois se considera que na Venezuela eles não estavam acostumados a trabalhar. Na análise, observamos como estes discursos são apoiados pelo contraste com as representações dos peruanos de sua própria identidade , que são concebidos como trabalhadores e trabalhadoras. Além disso, identificamos dilemas ideológicos, referentes a tensões entre discursos contraditórios dentro de um mesmo grupo ou entrevistado

    Repositioning small molecule drugs as allosteric inhibitors of the BFT-3 toxin from enterotoxigenic Bacteroides fragilis

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    Bacteroides fragilis is an abundant commensal component of the healthy human colon. However, under dysbiotic conditions, enterotoxigenic B. fragilis (ETBF) may arise and elicit diarrhea, anaerobic bacteremia, inflammatory bowel disease, and colorectal cancer. Most worrisome, ETBF is resistant to many disparate antibiotics. ETBF's only recognized specific virulence factor is a zinc-dependent metallopeptidase (MP) called B. fragilis toxin (BFT) or fragilysin, which damages the intestinal mucosa and triggers disease-related signaling mechanisms. Thus, therapeutic targeting of BFT is expected to limit ETBF pathogenicity and improve the prognosis for patients. We focused on one of the naturally occurring BFT isoforms, BFT-3, and managed to repurpose several approved drugs as BFT-3 inhibitors through a combination of biophysical, biochemical, structural, and cellular techniques. In contrast to canonical MP inhibitors, which target the active site of mature enzymes, these effectors bind to a distal allosteric site in the proBFT-3 zymogen structure, which stabilizes a partially unstructured, zinc-free enzyme conformation by shifting a zinc-dependent disorder-to-order equilibrium. This yields proBTF-3 incompetent for autoactivation, thus ablating hydrolytic activity of the mature toxin. Additionally, a similar destabilizing effect is observed for the activated protease according to biophysical and biochemical data. Our strategy paves a novel way for the development of highly specific inhibitors of ETBF-mediated enteropathogenic conditions
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