9,533 research outputs found

    Gene expression profiling of Mycobacterium avium subsp. paratuberculosis in simulated multi-stress conditions and within THP-1 cells reveals a new kind of interactive intramacrophage behaviour

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    Recent studies have identified in Mycobacterium avium subsp. paratuberculosis (MAP), already known as a pathogen in ruminants, a potential zoonotic agent of some autoimmune diseases in humans. Therefore, considering the possible risk for public health, it is necessary a thorough understanding of MAP's gene expression during infection of human host as well as the identification of its immunogenic and/or virulence factors for the development of appropriate diagnostic and therapeutic tools.In order to characterize MAP's transcriptome during macrophage infection, we analyzed for the first time the whole gene expression of a human derived strain of MAP in simulated intraphagosomal conditions and after intracellular infection of the human macrophage cell line THP-1 by using the DNA-microarray technology. Results showed that MAP shifts its transcriptome to an adaptive metabolism for an anoxic environment and nutrient starvation. It up-regulates several response factors to oxidative stress or intracellular conditions and allows, in terms of transcription, a passive surface peptidoglycan spoliation within the macrophage along with an intensification of the anabolic activity for lipidic membrane structures.These results indicate a possible interactive system between MAP and its host cell based on the internal mimicry unlike other intracellular pathogens, bringing new hypothesis in the virulence and pathogenicity of MAP and its importance in human health

    Use of spectroscopic indicators for the monitoring of bromate generation in ozonated wastewater containing variable concentrations of bromide

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    Time-resolved monitoring of bromate and other by-products formed into effluents treated with ozone or advanced oxidation processes in wastewater treatment plants (WWTPs) is time-consuming and expensive. This study examined whether concentrations of bromate formed in wastewater after ozonation in the presence of widely varying bromide levels (from ca. 0.7–21.2 mg/L) can be quantified based on measurements of changes in optical properties (differential UV absorbance (ΔUVA), spectral slopes, total or regional fluorescence) of the ozonated samples. Batch ozonation was carried out using a secondary effluent produced at a major wastewater treatment plant located in the Metropolitan Seattle Area. The tests involved raw and bromide-spiked samples treated with ozone doses from 0.1 to 1 mg O3/mg DOC. Measurements of the absorbance at 254 nm (UVA254), fluorescence and bromate concentrations were performed on the treated samples. In the ozonated wastewater the concentration of bromate increased approximately linearly, from 10 mg/L) tended to inhibit the generation of bromate. Relative reduction of UVA254 and total fluorescence (TF) were found to be good predictors of bromate generation. Specifically, exponential curves could adequately fit the non-linear relationships found to exist between the concentrations of bromate and the relative reductions of the UV254 and TF, for any initial bromide concentrations used in this study. Little formation of bromate was found to occur for reduction ranges for UVA254 and TF of 30–40% and 70–80% respectively. Conversely, rapid increases in bromate generation were observed when the decrease of UVA254 or TF exceeded these threshold values

    Analysis of the emergent climate change mitigation technologies

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    A climate change mitigation refers to efforts to reduce or prevent emission of greenhouse gases. Mitigation can mean using new technologies and renewable energies, making older equipment more energy efficient, or changing management practices or consumer behavior. The mitigation technologies are able to reduce or absorb the greenhouse gases (GHG) and, in particular, the CO2 present in the atmosphere. The CO2 is a persistent atmospheric gas. It seems increasingly likely that concentrations of CO2 and other greenhouse gases in the atmosphere will overshoot the 450 ppm CO2 target, widely seen as the upper limit of concentrations consistent with limiting the increase in global mean temperature from pre-industrial levels to around 2◦C. In order to stay well below to the 2◦C temperature thus compared to the pre-industrial level as required to the Paris Agreement it is necessary that in the future we will obtain a low (or better zero) emissions and it is also necessary that we will absorb a quantity of CO2 from the atmosphere, by 2070, equal to 10 Gt/y. In order to obtain this last point, so in order to absorb an amount of CO2 equal to about 10 Gt/y, it is necessary the implementation of the negative emission technologies. The negative emission technologies are technologies able to absorb the CO2 from the atmosphere. The aim of this work is to perform a detailed overview of the main mitigation technologies possibilities currently developed and, in particular, an analysis of an emergent negative emission technology: the microalgae massive cultivation for CO2 biofixation

    Traditional free-weight vs. variable resistance training applied to elite young soccer players during a short preseason: effects on strength, speed, and power performance

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    Maximizing the neuromuscular capacities of players is a critical challenge during short soccer preseasons. This study compared the effects of two strength-power training regimes, on the strength, speed, and power performance of elite young soccer players during a 4-week preseason. Twenty-five under-20 players from the same club were pair-matched in two training groups as follows: traditional training group (TTG) (n=13), athletes performed half-squat (HS) and jump-squat (JS) exercises as traditionally prescribed; and EB group (EBG) (n=12), athletes performed HS and JS with EB attached to the barbell. Vertical jump height, 20-m sprint velocity, change-of-direction (COD) speed, HS and JS power, and one-repetition maximum (1RM) in the HS were assessed pre, post 2-week, and post 4-week of training. An ANOVA two-way with repeated measures was used to assess the effects of both training protocols over the experimental period. Both strategies were effective for significantly improving HS and JS power (effect sizes [ES] 1.00 - 1.77), HS 1RM (ES = 1.68 and 1.51 for TTG and EBG, respectively), vertical jumping ability (ES 0.37 - 0.65), and COD speed (ES = 0.81 and 0.39 for TTG and EBG, respectively), when comparing pre- and post-measures. In contrast, both TTG and EBG failed to increase 20-m sprint velocity (ES ranging between -0.54 and 0.23). In conclusion, both training schemes were able to improve the strength and power performance, but not the sprint capacity of young soccer players. To accelerate strength gains over very-short time periods (i.e., 2-week), variable resistance training may be advantageous. Conversely, to optimize power adaptations in ballistic exercises across a similar time period, traditional FW training may be preferred

    Reaction of the NAD(P)H:flavin oxidoreductase from Escherichia coli with NADPH and riboflavin: identification of intermediates.

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    International audienceFlavin reductase catalyzes the reduction of free flavins by NAD(P)H. As isolated, Escherichia coli flavin reductase does not contain any flavin prosthetic group but accommodates both the reduced pyridine nucleotide and the flavin substrate in a ternary complex prior to oxidoreduction. The reduction of riboflavin by NADPH catalyzed by flavin reductase has been studied by static and rapid kinetics absorption spectroscopies. Static absorption spectroscopy experiments revealed that, in the presence of riboflavin and reduced pyridine nucleotide, flavin reductase stabilizes, although to a small extent, a charge-transfer complex of NADP+ and reduced riboflavin. In addition, reduction of riboflavin was found to be essentially irreversible. Rapid kinetics absorption spectroscopy studies demonstrated the occurrence of two intermediates with long-wavelength absorption during the catalytic cycle. Such intermediate species exhibit spectroscopic properties similar to those of charge-transfer complexes of oxidized flavin and NAD(P)H, and reduced flavin and NAD(P)+, respectively, which have been identified as intermediates during the reaction of flavoenzymes of the ferredoxin-NADP+ reductase family. Thus, a minimal kinetic scheme for the reaction of flavin reductase with NADPH and riboflavin can be proposed. After formation of the Michaelis complex of flavin reductase with NADPH and riboflavin, a first intermediate, identified as a charge-transfer complex of NADPH and riboflavin, is formed. It is followed by a second charge-transfer intermediate of enzyme-bound NADP+ and reduced riboflavin. The latter decays, yielding the Michaelis complex of flavin reductase with NADP+ and reduced riboflavin, which then dissociates to complete the reaction. These results support the initial hypothesis of a structural similarity between flavin reductase and the enzymes of the ferredoxin-NADP+ reductase family and extend it at a functional level

    Health care workers' influenza vaccination: motivations and mandatory mask policy

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    Background Vaccination of health care workers (HCW) against seasonal influenza (SI) is recommended but vaccination rate rarely reach >30%. Vaccination coverage against 2009 pandemic influenza (PI) was 52% in our hospital, whilst a new policy requiring unvaccinated HCW to wear a mask during patient care duties was enforced. Aims To investigate the determinants of this higher vaccination acceptance for PI and to look for an association with the new mask-wearing policy. Methods A retrospective cohort study, involving HCW of three critical departments of a 1023-bed, tertiary-care university hospital in Switzerland. Self-reported 2009-10 SI and 2009 PI vaccination statuses, reasons and demographic data were collected through a literature-based questionnaire. Descriptive statistics, uni- and multivariate analyses were then performed. Results There were 472 respondents with a response rate of 54%. Self-reported vaccination acceptance was 64% for PI and 53% for SI. PI vaccination acceptance was associated with being vaccinated against SI (OR 9.5; 95% CI 5.5-16.4), being a physician (OR 7.7; 95% CI 3.1-19.1) and feeling uncomfortable wearing a mask (OR 1.7; 95% CI 1.0-2.8). Main motives for refusing vaccination were: preference for wearing a surgical mask (80% for PI, not applicable for SI) and concerns about vaccine safety (64%, 50%) and efficacy (44%, 35%). Conclusions The new mask-wearing policy was a motivation for vaccination but also offered an alternative to non-compliant HCW. Concerns about vaccine safety and efficiency and self-interest of health care workers are still main determinants for influenza vaccination acceptance. Better incentives are needed to encourage vaccination amongst non-physician HC

    PRELIMINARY TAKE-OFF ANALYSIS AND SIMULATION FOR A PRANDTLPLANE COMMERCIAL AIRCRAFT

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    The paper describes the take-off performances and characteristics of an unconventional aircraft, called PrandtlPlane. The PrandtlPlane has a box-wing architecture, founded on the “Best Wing System” concept due to L. Prandtl, that minimizes the induced drag once wingspan and lift are given. This configuration has the potential to be a more efficient alternative to conventional tube-and-wing aircraft, and it is under investigation in the framework of the PARSIFAL project, funded by the European Union in the Horizon 2020 program. A numerical simulation tool for the take-off dynamics of the aircraft, based on the non-linear equations of motion, has been developed in order to evaluate the performance of the aircraft in take-off condition. The VLM solver has been integrated into this tool in order to evaluate the aerodynamic performance of the aircraft in ground effect at each moment of the manoeuvre. The same assessments have been made for a conventional tube-and-wing reference aircraft, with the aim of conducting a performance comparison with the reference PrandtlPlane. The preliminary results obtained show the aerodynamic and aeromechanical advantages of the reference PrandtlPlane, in terms of runway length and passenger comfort

    Origin of pyroxenites in the oceanic mantle and their implications on the reactive percolation of depleted melts

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    Pyroxenites are diffuse in fertile mantle peridotites and considered an important component in the mantle source of oceanic basalts. They are rarely documented in abyssal and ophiolitic peridotites representing residual mantle after melt generation, and few studies defining their origin are to date available. We present a field-based microstructural and geochemical investigation of the pyroxenite layers associated with depleted peridotites from the Mt. Maggiore ophiolitic body (Corsica, France). Field and petrographic evidence indicate that pyroxenite formation preceded the melt\u2013rock interaction history that affected this mantle sector during Jurassic exhumation, namely (1) spinel-facies reactive porous flow leading to partial dissolution of the pyroxenites, and (2) plagioclase-facies melt impregnation leading to [plagioclase + orthopyroxene] interstitial crystallization. Pyroxenes show major element compositions similar to abyssal pyroxenites from slow-spreading ridges, indicative of magmatic segregation at pressures higher than 7 kbar. Both the parental melts of pyroxenites and the melts involved in the subsequent percolation were characterized by Na2O-poor, LREE-depleted compositions, consistent with unaggregated melt increments. This implies that they represent the continuous evolution of similarly depleted melts leading to different processes (pyroxenite segregation and later melt\u2013rock interaction) during their upward migration. To support the genetic relation and the continuity between the formation of pyroxenites and the subsequent melt\u2013rock interaction history, we modeled all the documented processes in sequence, i.e.: (1) formation of single-melt increments after 6% mantle decompressional fractional melting; (2) high-pressure segregation of pyroxenites; (3) spinel-facies reactive porous flow, (4) plagioclase-facies melt impregnation. The early fractionation of pyroxenites leads to a decrease in pyroxene saturation that is necessary for the subsequent reactive porous flow process, without any significant change in the melt REE composition

    EFEITOS DA PULVERIZAÇÃO FOLIAR COM SILÍCIO NA TOLERÂNCIA DE Theobroma cacao L. (MALVACEAE) AO DÉFICE HÍDRICO

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    Theobroma cacao L. (MALVACEAE) AO DÉFICE HÍDRICO Assim como em várias regiões do Brasil, o norte do estado do Espírito Santo, pólo produtor de cacau, apresenta intensos períodos de estiagem que provocam queda na produção agrícola. É anseio de qualquer agricultor o desenvolvimento de tecnologias de qualidade a baixo custo que permitam aumentar a produção agrícola, e é nesse contexto que surge a adubação com silício (Si), uma tecnologia pouco explorada no Brasil e que já se mostra promissora na manutenção ou aumento da produtividade em situações de estresse hídrico. Sendo assim, objetivou-se com este trabalho verificar as respostas fisiológicas e anatômicas de um clone de cacau (PH 16) submetido a um ciclo de défice hídrico após pulverização foliar com Si, visando a determinar se o Si confere tolerância à seca. O experimento foi instalado em casa de vegetação, no delineamento de blocos casualizados, com quatro repetições, em arranjo fatorial 2 x 3, constituído de dois regimes hídricos, irrigado ou não irrigado, e três doses de Si, 0,0, 1,5 e 3,0 mg/mL, com pó molhável de SiO2. Após vinte dias de suspensão da irrigação, avaliações foram realizadas na 2ª ou 3ª folha completamente expandida a partir do ápice do eixo ortotrópico. Os resultados mostraram que o teor de fenóis foi elevado com a aplicação de SiO2 independente da dose. O uso do SiO2 melhorou a estabilidade das membranas celulares das plantas sob défice hídrico, e a atividade de algumas enzimas antioxidantes: catalase (CAT), peroxidase do ascorbato (APX), peroxidase do guaiacol (POD) e polifenoloxidase (PPO), sendo a dose de 1,5 mg/mL a melhor. A aplicação dessa dose favoreceu as reações fotoquímicas, a taxa fotossintética, a eficiência do uso da água e a taxa de carboxilação das plantas de cacau sob défice. A densidade estomática foi reduzida nas plantas não irrigadas sob maior dose de Si. Contudo, a aplicação de Si não interferiu no conteúdo de água das folhas sob défice, apesar de reduzir o potencial hídrico foliar. Presume-se que a mucilagem tenha um papel importante na manutenção do conteúdo hídrico das folhas de T. cacao. As espessuras dos tecidos foliares (epiderme, parênquima paliçádico e esponjoso), bem como o teor de pigmentos fotossintetizantes e o conteúdo de Si nas folhas, não sofreram influência das doses de Si. Desse modo, sugere-se que o acúmulo de Si sobre as folhas foi benéfica, sendo a dose de 1,5 mg/mL, a mais eficiente para a tolerância das plantas de cacau ao défice hídrico. Palavras-chave: Anatomia, cacau, défice hídrico, enzimas antioxidantes, fotossíntese, silício
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