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Abstract: This paper complements the existing studies of Bora flow properties in the Vipava valley with the study of Bora turbulence in a lower region of the troposphere. The turbulence characteristics of Bora flow were derived from high resolution Doppler wind lidar measurements during eight Bora wind episodes that occurred in November and December 2019. Based on the vertical profiles of wind velocity, from 80 to 180 m above the valley floor, the turbulence intensity related to all three spatial directions and the along-wind integral length scales related to three velocity components were evaluated and compared to the approximations given in international standards. The resulting turbulence characteristics of Bora flow in a deep mountain valley exhibited interesting behaviour, differing from the one expected and suggested by standards. The intensity of turbulence during Bora episodes was found to be quite strong, especially regarding the expected values for that particular category of terrain. The specific relationship between along-wind, lateral and vertical intensity was evaluated as well. The scales of turbulence in the along-wind direction were found to vary widely between different Bora episodes and were rather different from the approximations given by standards, with the most significant deviations observed for the along-wind length scale of the vertical velocity component. Finally, the periodicity of flow structures above the valley was assessed, yielding a wide range of possible periods between 1 and 10 min, thus confirming some of the previous observations from the studies of Bora in the Vipava valley.
Keywords: doppler wind lidar, Bora wind, turbulence intensity, complex terrain, turbulence integral length scale
Published in RUNG: 05.11.2021; Views: 2026; Downloads: 42
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Abstract: According to current models, dimeric DNA Polymerases coordinate the replication of DNA leading and lagging strands. However, it was recently shown that trimeric DNA Polymerases, assembled in vitro, replicate the lagging strand more efficiently than dimeric replicases. Here we show that the τ, α, ε, and θ subunits of Escherichia coli DNA Polymerase III can be assembled in vivo, yielding the trimeric τ3α3ε3θ3 complex. Further, we propose a molecular model of this complex, whose catalytic action was investigated using model DNA substrates. Our observations indicate that trimeric DNA replicases reduce the gap between leading and lagging strand synthesis.
Keywords: Trimeric DNA Polymerase, E. coli, DNA Polymerase III, τ3α3ε3θ3 complex, Triple DNA extension
Published in RUNG: 27.01.2021; Views: 1965; Downloads: 0
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Abstract: This study provides information on mercury (Hg) localization, speciation and ligand environment in edible mushrooms: Boletus edulis, B. aereus and Scutiger pes-caprae collected at non-polluted and Hg polluted sites, by LA-ICP-MS, SR-μ-XRF and Hg L3-edge XANES and EXAFS. Mushrooms (especially young ones) collected at Hg polluted sites can contain more than 100 μg Hg g−1 of dry mass. Imaging of the element distribution shows that Hg accumulates mainly in the spore-forming part (hymenium) of the cap. Removal of hymenium before consumption can eliminate more than 50% of accumulated Hg. Mercury is mainly coordinated to di-thiols (43–82%), followed by di-selenols (13–35%) and tetra-thiols (12–20%). Mercury bioavailability, as determined by feeding the mushrooms to Spanish slugs (known metal bioindicators owing to accumulation of metals in their digestive gland), ranged from 4% (S. pes-caprae) to 30% (B. aereus), and decreased with increasing selenium (Se) levels in the mushrooms. Elevated Hg levels in mushrooms fed to the slugs induced toxic effects, but these effects were counteracted with increasing Se concentrations in the mushrooms, pointing to a protective role of Se against Hg toxicity through HgSe complexation. Nevertheless, consumption of the studied mushroom species from Hg polluted sites should be avoided.
Keywords: edible mushrooms, HgSe complex, imaging of elemental distribution, LA-ICP-MS, alpha-XRF, XAS
Published in RUNG: 24.10.2019; Views: 3331; Downloads: 0
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Abstract: We report the crystallisation of three forms of copper(II) isonicotinate-N-oxide complex and their phase interconversion via solvent-mediated crystal to crystal transformation. The different forms of copper complex have been isolated and characterised by single crystal X-ray diffraction. Gel phase crystallisation performed in hydrogels, low molecular weight gels and gels of tailored gelator showed crystal habit modification. Crystallisation in aqueous ethanol resulted in concomitant formation of blue (form-I) and green (form-II/IV) crystals while use of low molecular weight gel results in selective crystallization of the blue form-I under identical conditions. Comparison of gel phase and the solution state crystallisation in various solvent compositions reveals that the blue form-I is the thermodynamically stable form under ambient conditions.
Keywords: copper(II) complex, gel phase crystallisation, crystal habit modification, isonicotinate-N-oxide, X-ray diffraction
Published in RUNG: 08.11.2018; Views: 3381; Downloads: 0
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