669 research outputs found
DNA adducts in fish following an oil spill exposure
On 12 December 1999, one third of the load of the Erika tanker, amounting to about 10,000 t crude oil flowed into sea waters close to the French Atlantic Coast. This oil contained polycyclic aromatic compounds (PAC) that are known to be genotoxic. Genotoxic effects induce DNA adducts formation, which can thus be used as pollution biomarkers. Here, we assessed the genotoxic impact of the “Erika” oil spill by DNA adducts detection in the liver of immature fishes (Solea solea) from four locations of the French Brittany coasts. Two months after the spill, a high amount of DNA adducts was found in samples from all locations, amounting to 92–290 DNA adduct per 109 nucleotides. Then total DNA adduct levels decreased to reach about 50 adducts per 109 nucleotides nine months after the spill. In vitro experiments using human cell cultures and fish liver microsomes evidence the genotoxicity of the Erika fuel. They also prove the formation of reactive species able to create DNA adducts. Furthermore, in vitro and in vivo DNA adducts fingerprints are similar, thus confirming that DNA adducts are a result of the oil spill
The influence of initial xylose concentration, agitation, and aeration on ethanol production by Pichia stipitis from rice straw hemicellulosic hydrolysate
Rice straw hemicellulosic hydrolysate was used as fermentation medium for ethanol production by Pichia stipitis NRRL Y-7124. Shaking bath experiments were initially performed aiming to establish the best initial xylose concentration to be used in this bioconversion process. In the sequence, assays were carried out under different agitation (100 to 200 rpm) and aeration (V flask/V medium ratio varying from 2.5 to 5.0) conditions, and the influence of these variables on the fermentative parameters values (ethanol yield factor, Y P/S; cell yield factor, Y X/S; and ethanol volumetric productivity, Q P) was investigated through a 22 full-factorial design. Initial xylose concentration of about 50 g/l was the most suitable for the development of this process, since the yeast was able to convert substrate in product with high efficiency. The factorial design assays showed a strong influence of both process variables in all the evaluated responses. The agitation and aeration increase caused a deviation in the yeast metabolism from ethanol to biomass production. The best results (Y P/S = 0.37 g/g and Q P = 0.39 g/l.h) were found when the lowest aeration (2.5 V flask/V medium ratio) and highest agitation (200 rpm) levels were employed. Under this condition, a process efficiency of 72.5% was achieved. These results demonstrated that the establishment of adequate conditions of aeration is of great relevance to improve the ethanol production from xylose by Pichia stipitis, using rice straw hemicellulosic hydrolysate as fermentation medium.The financial support from Fapesp (Brazil) is gratefully acknowledged
Effect of light and darkness on the growth and development of downy mildew pathogen Hyaloperonospora arabidopsidis
Disease development in plants requires a susceptible host, a virulent pathogen, and a favourable environment. Oomycete pathogens cause many important diseases and have evolved sophisticated molecular mechanisms to manipulate their hosts. Day length has been shown to impact plant‐oomycete interactions but a need exists for a tractable reference system to understand the mechanistic interplay between light regulation, oomycete pathogen virulence, and plant host immunity. Here we present data demonstrating that light is a critical factor in the interaction between Arabidopsis thaliana and its naturally occurring downy mildew pathogen Hyaloperonospora arabidopsidis (Hpa). We investigated the role of light on spore germination, mycelium development, sporulation and oospore formation of Hpa, along with defence responses in the host. We observed abundant Hpa sporulation on compatible Arabidopsis under day lengths ranging from 10 to 14 hours. Contrastingly, exposure to constant light or constant dark suppressed sporulation. Exposure to constant dark suppressed spore germination, mycelial development and oospore formation. Interestingly, exposure to constant light stimulated spore germination, mycelial development and oospore formation. A biomarker of plant immune system activation was induced under both constant light and constant dark. Altogether, these findings demonstrate that Hpa has the molecular mechanisms to perceive and respond to light and that both the host and pathogen responses are influenced by the light regime. Therefore, this pathosystem can be used for investigations to understand the molecular mechanisms through which oomycete pathogens like Hpa perceive and integrate light signals, and how light influences pathogen virulence and host immunity during their interactions
Ethanol production from xylose by pichia stipitis NRRL Y-7124 in a stirred tank bioreactor
The ethanol production by Pichia stipitis was evaluated in a stirred tank bioreactor using semidefined medium containing xylose (90.0 g/l) as the main carbon source. Experimental assays were performed
according to a 22 full factorial design to evaluate the influence of aeration (0.25 to 0.75 vvm) and agitation (150 to 250 rpm) conditions on ethanol production. In the studied range of values, the agitation increase and aeration decrease favored ethanol production, which was maximum (26.7 g/l) using 250 rpm and 0.25 vvm,
conditions that gave a volumetric oxygen transfer coefficient (kLa value) of 4.9 h-1. Under these conditions, the ethanol yield factor, ethanol productivity, and the process efficiency were 0.32 g/g, 0.32 g/l.h, and 63%, respectively. These results are promising and contribute to the development of a suitable process for ethanol
production from xylose by Pichia stipitis.The authors gratefully acknowledge Santander, Fapesp, Capes, and CNPq (Brazil)
Een verkenning van interventies om zelfstandige terugkeer te stimuleren
To promote the voluntary return of immigrants who are obliged to depart, an exploratory study was conducted into behavioural interventions in other social spheres that could be used in the return process. It looked for behavioural interventions that encourage people to exhibit other behaviour, which they were not initially prepared to exhibit. It looked at both behavioural interventions that focus on conscious behaviour modification and the possibility of using nudges that engage automatic and unconscious thought processes.Het voorliggende onderzoek bevat de resultaten van de verkenning van de mogelijkheden om inzichten over gedragsbeïnvloeding toe te passen in de begeleiding van vertrekplichtige vreemdelingen bij zelfstandige terugkeer. In dit onderzoek zijn de belangrijkste belemmeringen voor terugkeer geïnventariseerd, zijn zes gedragsinterventies uit andere beleidsterreinen dan de vreemdelingenketen nader bestudeerd en is de mogelijke bruikbaarheid van nudging voor het stimuleren van terugkeer in kaart gebracht. INHOUD: 1. Inleiding 2. Belemmeringen bij zelfstandige terugkeer 3. Gedragsinterventies andere sociale domeinen 4. Toepasbaarheid nudges bij terugkeer 5. Samenvatting en conclusi
Predicting survival of de novo metastatic breast cancer in Asian women: Systematic review and validation study
10.1371/journal.pone.0093755PLoS ONE94-POLN
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
PRELIMINARY STUDY OF WATER INJECTION ON THE COMBUSTION AND EMISSIONS CHARACTERISTICS IN A HCCI ETHANOL ENGINE
Our dependence on fossil fuels coupled with concerns about harmful emissions have motivated researchers to look for renewable fuels that have clean combustion and for advanced combustion modes. In this context, homogeneous charge compression ignition (HCCI) is an emerging technology which offers an alternative to conventional spark ignition and compression ignition engines and can operate on renewable fuels. Low temperature combustion, which can result in low NOx emissions with high indicated efficiency, is the more important characteristic of this combustion mode. It’s main problem is the combustion timing control due to lack of direct ignition control, once HCCI flame initiation is based on charge thermal state. Thus, controlled auto-ignition (CAI) combustion mode has been proposed. Several methods were proposed for combustion phasing control, between them, the injection of water in the intake manifold. This work investigated the influence of water injection in the intake runner of an ethanol HCCI cylinder from a converted three-cylinder diesel generator set, in which two cylinders operated on conventional diesel combustion and one diesel cylinder provided recycled exhaust gas for the one cylinder running on ethanol HCCI combustion. The water injection was used to control the CA50 combustion parameter. The results show that water injection is an efficient strategy to control the combustion timing, since the reactivity of the mixture can be controlled. The results at 400 and 600 kPa of IMEP and 1800 rpm indicated a good combustion stability, high efficiency and low emissions characteristics. The highest indicated fuel conversion efficiency found was 36.9% for 600 kPa of IMEP and 8 CAD of CA50. However, for 200 kPa of IMEP the combustion was unstable, the indicated efficiency was deteriorated and indicted CO emissions was high
Nordic cooperation amid pandemic travel restrictions
Since 2020, the Nordic countries have been confronted with the Covid-19 pandemic, which has been a multi-level stress test for the region. The strong basis of open borders and free movement in Nordic cooperation has been questioned by national pandemic measures, including wide travel restrictions. The Nordic dimension to pandemic responses has largely been missing, the trust between the countries has arguably been put to test and cross-border commuters have been subjected to differential treatment. Especially cross-border regions have suffered the consequences of travel restrictions, causing disruptions to work and private life. The report draws attention to the preparedness of the Nordic Region to jointly confront global crises. It explores the different strategies and travel restrictions adopted by four Nordic countries: Denmark, Finland, Norway and Sweden. It also studies how Nordic cooperation functioned in a time of crisis. At the local level, it examines the economic, labour market and social implications for three cross-border regions, that is, Tornedalen, Svinesund and Öresund. The report finds that while there is room for improvement in handling a crisis like the pandemic, there are diverging views on the desirability to have all-Nordic approaches to situations affecting national security. The consequences are, however, serious for free movement and the aim to become the most integrated region in the world.publishedVersio
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