367 research outputs found

    An oxygen isotope record of lacustrine opal from a European Maar indicates climatic stability during the Last Interglacial

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    The penultimate temperate period, 127–110 ka before present (BP), bracketed by abrupt shifts of the global climate system initiating and terminating it, is considered as an analogue of the Holocene because of a similar low global ice‐volume. Ice core records as well as continental and marine records exhibit conflicting evidence concerning the climate variability within this period, the Last Interglacial. We present, for the first time, a high‐resolution record of oxygen isotopes in diatom opal of the Last Interglacial obtained from the Ribains Maar in France (44°50′09″N 3°49′16″E). Our results indicate that the Last Interglacial in southwestern Europe was generally a period of climatic stability. The record shows that the temperate period was initiated by an abrupt warm event followed midway by a minor climatic transition to a colder climate. An abrupt isotopic depletion that occurs simultaneously with abrupt changes in pollen and diatom assemblages marks the end of the temperate period, and is correlative with the Melisey I stadial. Variations in the isotopic composition of lake‐water related to the isotopic composition of precipitation and evaporation dominate the biogenic opal oxygen isotope record

    clostridium perfringens occurrence and ribotypes in healthy broilers reared in different european countries

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    Abstract The main aim of this study was to investigate the occurrence and ribotypes of Clostridium perfringens in broiler flocks reared in 2 European countries that apply European Union Regulation 1831/2003. A total of 1,532 cecum contents were collected between June 2005 and November 2006 from birds belonging to 51 intensively reared flocks produced in the Czech Republic and 41 intensive production, organic, and free-range flocks reared in Italy. Clostridium perfringens was detected in 64.7 and 82.9% of the Czech Republic and Italian flocks, respectively, at mean loads ranging between 3.65 and 4.77 log10 cfu per gram of cecum content. More than 1 ribotype was identified among isolates belonging to the same flock in 57.1 and 76.5% of the Czech Republic and Italian flocks, respectively. Moreover, common ribotypes were identified between strains belonging to 2 up to 8 different flocks. In particular, 4 ribotypes were shared between strains isolated in the 2 European countries. The results of this study report on C. perfringens occurrence and mean populations in broilers reared on diets devoid of antibiotic growth promoters. Moreover, these findings show for the first time the presence of common ribotyping profiles among isolates collected from birds reared more than 1,000 km apart

    Aptamers against the β-conglutin allergen: Insights into the behavior of the shortest multimeric (intra)molecular dna gquadruplex

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    In previous work, a 93-mer aptamer was selected against the anaphylactic allergen, β-conglutin and truncated to an 11-mer, improving the affinity by two orders of magnitude, whilst maintaining the specificity. This 11-mer was observed to fold in a G-quadruplex, and preliminary results indicated the existence of a combination of monomeric and higher-order structures. Building on this previous work, in the current study, we aimed to elucidate a deeper understanding of the structural forms of this 11-mer and the effect of the structure on its binding ability. A battery of techniques including polyacrylamide gel electrophoresis, high-performance liquid chromatography in combination with electrospray ionization time-of-flight mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight, thermal binding analysis, circular dichroism and nuclear magnetic resonance were used to probe the structure of both the 11-mer and the 11-mer flanked with TT- at either the 5′ or 3′ end or at both ends. The TT-tail at the 5′ end hinders stacking effects and effectively enforces the 11-mer to maintain a monomeric form. The 11-mer and the TT- derivatives of the 11-mer were also evaluated for their ability to bind its cognate target using microscale thermophoresis and surface plasmon resonance, and biolayer interferometry confirmed the nanomolar affinity of the 11-mer. All the techniques utilized confirmed that the 11-mer was found to exist in a combination of monomeric and higher-order structures, and that independent of the structural form present, nanomolar affinity was observed

    Potential reactivity assessment of mechanically activated kaolin as alternative cement precursor

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    This work aims to assess the potential reactivity of a mechanically activated kaolin for its use as an alternative cement precursor. The mechanical activation was successfully achieved by grinding at different rotation speeds (250, 300, and 350 rpm) and times (60, 90, and 120 min), obtaining a highly amorphous and reactive material. The amorphization was monitored through XRD with amorphous content estimation and FTIR deconvolution. The potential reactivity was evaluated through chemical attacks, obtaining SiO2 and Al2O3 availabilities up to 95 wt% and 93 wt% of total SiO2 and Al2O3 content. XRD and FTIR also allowed the identification of the nonreactive phases on the insoluble residue after chemical attacks. NMR analysis revealed that part of the aluminium was in IV coordination, limiting the reactivity in the alkali activation process. This work demonstrated the effectiveness of mechanical activation as a greener treatment than thermal dehydroxylation to increase the raw kaolin's reactivity

    The multi-risk vulnerability of global coal regions in the context of mine closure

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    Coal mining industries face real challenges to meet legal demands on a low carbon future. The history of coal in industrial transitions seems to come to a rapid end, accompanied by widespread boom of closing active coal mining projects. This change can result in negative ramifications for coal mining regions, involving a complex interplay of multiple risks. In this paper, we aim to analyse the complexity of environmental, social, and governance factors that can cause significant difficulties in closure of coal mining operations. We identify multi-factor risk profiles for operating mines by applying spatially explicit indicators within a proposed multi-risk framework. The indicators have not been captured by conventional market, as they tend to be more long-term oriented in the context of strategy and performance. We map eight risk categories: stability, water and climate, biodiversity, vulnerability of land uses, indigenous people, social fragility, political fragility, and regulatory environment, and analyse their effect on a global dataset of active open pit coal mines. The spatial analysis reveals that a significant proportion of the projects face accumulation of multiple risk factors. A total of 552 projects out of 916 show medium to very high-risk occurrence. In this paper, we present global risk vulnerability across the coal mining projects by indicating extent to which operators of the mines face multiple risk factors when planning for closure

    Assessing the effects of forest-to-bog restoration in the hyporheic zone at known Atlantic salmon (Salmo salar) spawning sites

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    In the UK, large areas of blanket bogs were afforested with non-native conifers between the 1960s and the 1980s. Following recognition of the detrimental effects of such practice on biodiversity and carbon stocks, large-scale restoration trials started in the late 1990s and are further supported by recent changes in policy. The removal of forestry from peatlands is likely to be a widespread land-use change in the coming decades and could affect adjacent freshwater systems. This study aimed to investigate whether forestry removal with drain blocking affected nearby spawning sites used by Atlantic salmon (Salmo salar). We analysed the chemistry of hyporheic (beneath and just above the streambed) and surface water, and measured sediment deposition upstream of, within and downstream of a forestry block in the north of Scotland, during and after restoration management operations. We found no immediate effect of management except on potassium and zinc concentrations, which increased after restoration. The general lack of effect is attributed to catchment properties, including the small proportion of catchment (< 5 %) affected by management, and to dilution effects related to heavy precipitation during the intervention phase. We suggest that longer-term monitoring should be implemented as the sizes of areas undergoing restoration management increases

    Bifidobacterium canis sp. Nov., a novel member of the bifidobacterium pseudolongum phylogenetic group isolated from faeces of a dog (canis lupus f. familiaris)

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    A fructose-6-phosphate phosphoketolase-positive strain (GSD1FST) was isolated from a faecal sample of a 3 weeks old German Shepherd dog. The closest related taxa to isolate GSD1FST based on results from the EZBioCloud database were Bifidobacte-rium animalis subsp. animalis ATCC 25527T, Bifidobacterium animalis subsp. lactis DSM 10140T and Bifidobacterium anseris LMG 30189T, belonging to the Bifidobacterium pseudolongum phylogenetic group. The resulting 16S rRNA gene identities (compared length of 1454 nucleotides) towards these taxa were 97.30, 97.23 and 97.09 %, respectively. The pairwise similarities of strain GSD1FST using argS, atpA, fusA, hsp60, pyrG, rpsC, thrS and xfp gene fragments to all valid representatives of the B. pseudo-longum phylogenetic group were in the concatenated range of 83.08–88.34 %. Phylogenomic analysis based on whole-genome methods such as average nucleotide identity revealed that bifidobacterial strain GSD1FST exhibits close phylogenetic relatedness (88.17 %) to Bifidobacetrium cuniculi LMG 10738T. Genotypic characteristics and phylogenetic analyses based on nine molecular markers, as well as genomic and comparative phenotypic analyses, clearly proved that the evaluated strain should be considered as representing a novel species within the B. pseudolongum phylogenetic group named as Bifidobacterium canis sp. nov. (GSD1FST=DSM 105923T=LMG 30345T=CCM 8806T)

    APOE polymorphism and its effect on plasma C-reactive protein levels in a large general population sample

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    The literature on association between apolipoprotein E (APOE) gene variations and plasma levels of C-reactive protein (CRP) remains inconsistent, mainly due to low statistical power of previous studies. To clarify this question, we analysed data from large population sample of randomly selected individuals from 7 Czech towns (2886 males and 3344 females, the HAPIEE study). In both males and females, the lowest levels of plasma hsCRP were observed in the carriers of the APOE ε4ε4 and ε4ε3 genotypes. The median (inter-quartile range, IQR) concentration of hsCRP in carriers of the most common APOE ε3ε3 genotype (two thirds of participants) was 1.13 (IQR 0.56; 2.33) mg/l in men and 1.23 (IQR 0.61; 2.65) mg/l in women, compared with 0.72 (IQR 0.61; 0.86) mg/l in male and 0.72 (IQR 0.61-0.85) mg/l in female carriers of APOE ε4ε3/ε4ε4 genotypes; the differences were statistically significant (p<0.001). The association between APOE and CRP was not materially affected by adjustment for age, sex, history of cardiovascular disease or cardiovascular risk factors. This study, the largest to date, provides robust evidence of an association between plasma hsCRP and the APOE genotype, an association not explained by history of cardiovascular disease nor its risk factors

    Acetylcholinesterase sensors based on gold electrodes modified with dendrimer and polyaniline: A comparative research

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    Potentiometric and amperometric enzyme sensors based on modified gold electrodes have been developed and compared in pesticide determination. PAMAM dendrimer (generation G4) stabilized with 1-hexadecanethiol was used for the immobilization of acetylcholinesterase from electric eel and choline oxidase from Alcaligenes species in the assembly of amperometric sensor. Polyaniline-doped with camphorsulfonic acid was used to obtain potentiometric response. Trichlorfon, carbofuran and eserine suppress the biosensor response due to their inhibitory effect. The detection limits of 0.003 and 200 nmol l-1 (trichlorfon), 0.04 and 6 nmol l-1 (carbofuran) and 0.1 and 700 nmol l-1 were obtained for amperometric and potentiometric sensors, respectively. The difference in the biosensor behavior and the high sensitivity of the dendrimer modified sensor to the inhibitors is due to the specific organization of protein layer at charged surface of the modifier macromolecules. © 2004 Elsevier B.V. All rights reserved

    Schreibersite: an effective catalyst in the formose reaction network

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    We report on the ability of the meteoritic material schreibersite to catalyze the generation of higher sugars from simple carbohydrates in the formose reaction network. Since the analysis of carbonaceous meteorites like the Murchison meteorite it has become generally accepted that a substantial amount of organic material has been delivered to the early earth and, therefore, ought to be considered in scenarios for the origin (s) of life. Also for the open question of accessible phosphorus sources, an extraterrestrial material called schreibersite has been identified that is capable of releasing soluble and reactive phosphorus oxyanions that would react with organics to form for instance nucleotides and membrane associated molecules. We have reinvestigated this material using capillary electrophoresis to monitor its corrosion process in water and probed its ability to phosphorylate a wide range of organics. Although showing a poor reactivity of schreibersite, we have found that the material catalyzes the aldol reaction of small carbohydrates forming larger sugar molecules. This reaction in the formose reaction network is a prebiotically likely route to biologically relevant sugars. The results of our study present one of the first instances of connecting extraterrestrial material to prebiotic chemistry on the early earth
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