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16. Localization, ligand environment, bioavailability and toxicity of mercury in Boletus spp. and Scutiger pes-caprae mushroomsAnja Kavčič, Klemen Mikuš, Marta Debeljak, Johannes Teun van Elteren, Iztok Arčon, Alojz Kodre, Peter Kump, Andreas-Germanos Karydas, Alessandro Migliori, Mateusz Czyzycki, Katarina Vogel-Mikuš, 2019, izvirni znanstveni članek Opis: 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.
Ključne besede: edible mushrooms, HgSe complex, imaging of elemental distribution, LA-ICP-MS, alpha-XRF, XAS
Objavljeno v RUNG: 24.10.2019; Ogledov: 5471; Prenosov: 0
Gradivo ima več datotek! Več... |
17. STUDY OF ATMOSPHERIC AEROSOL PROPERTIES IN THE VIPAVA VALLEYLonglong Wang, doktorska disertacija Opis: The aim of the dissertation was to study aerosol loading distributions and properties over the Vipava valley, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin.
An infrared Mie and a two-wavelength polarization Raman lidar systems
were used as main detection tools. The polarization Raman lidar, which
provides the capability to extract the extinction coefficient, backscatter coefficients, depolarization ratio, backscatter Ångström exponent, lidar ratio and
water vapor mixing ratio profiles, was itself designed, built and calibrated as
a part of this thesis. Lidar data, combined with in-situ measurements, was
used to determine detailed information on different aerosol types. Vertical
profiles of aerosol mass concentration were extracted from the Mie lidar data
taken in April 2016, where the in-situ measurements of aerosol size distribution and number concentration as well as aerosol absorption coefficient and black carbon mass concentration were used to estimate the mass extinction efficiency (MEE). Aerosol morphology and chemical composition determined by SEM-EDX on sampled particles were used for the identification
of primary aerosol types. Two cases with different atmospheric conditions
(long range mineral dust transport and local biomass burning) and different
expected the dominant presence of specific aerosol types (mineral dust and
soot) were investigated in more detail. They revealed significantly different
aerosol properties and distributions within the valley, affecting radiative heat
exchange.
A more detailed investigation of aerosol properties throughout the troposphere in different atmospheric conditions was made possible by the two-wavelength polarization Raman lidar system, deployed in Ajdovščina (town
of Vipava valley) from September 2017. Using its aerosol identification capabilities, based on particle depolarization ratio and lidar ratio measurements,
it was possible to identify predominant aerosol types in the observed atmospheric structures, for example in different atmospheric layers in the case of
the stratified atmosphere. Primary anthropogenic aerosols within the valley were found to be mainly emitted from two sources: individual domestic
heating systems, which mostly use biomass fuel and traffic. Natural aerosols,
transported over large distances, such as mineral dust and sea salt, were observed both above and entering into the planetary boundary layer. Backscatter contribution of each aerosol type was separated and the corresponding
extinction contribution was derived from lidar observations.
Ključne besede: Vipava valley, aerosol distribution, aerosol characterization, lidar
remote sensing, in-situ measurements, aerosol loading.
Objavljeno v RUNG: 23.10.2018; Ogledov: 8608; Prenosov: 164
 Celotno besedilo (29,39 MB) |
18. Determination of petrophysical properties of sedimentary rocks by optical methodsDorota Korte, Dejan Kaukler, Mattia Fanetti, Humberto Cabrera, Efrain Daubronte, Mladen Franko, 2017, izvirni znanstveni članek Ključne besede: sedimentary rocks, beam deflection spectroscopy, grain size distribution, petrophysical
properties, chemical composition
Objavljeno v RUNG: 06.02.2017; Ogledov: 5197; Prenosov: 0
Gradivo ima več datotek! Več... |
19. Accurate estimation of the entropy of rotation-translation probability distributionsFederico Fogolari, Cedrix Jurgal Dongmo Foumthuim, Sara Fortuna, Miguel Angel Soler, Alessandra Corazza, Gennaro Esposito, 2016, izvirni znanstveni članek Opis: The estimation of rotational and translational entropies in the context of ligand binding has been the subject of long-time investigations. The high dimensionality (six) of the problem and the limited amount of sampling often prevent the required resolution to provide accurate estimates by the histogram method. Recently, the nearest-neighbor distance method has been applied to the problem, but the solutions provided either address rotation and translation separately, therefore lacking correlations, or use a heuristic approach. Here we address rotational–translational entropy estimation in the context of nearest-neighbor-based entropy estimation, solve the problem numerically, and provide an exact and an approximate method to estimate the full rotational–translational entropy.
Ključne besede: entropy, probability distribution, molecular dynamics, nearest-neighbor
Objavljeno v RUNG: 11.10.2016; Ogledov: 5171; Prenosov: 0
Gradivo ima več datotek! Več... |
20. The AMIGA Muon Counters of the Pierre Auger Observatory: Performance and Studies of the Lateral Distribution FunctionBrian Wundheiler, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, objavljeni znanstveni prispevek na konferenci Opis: The AMIGA enhancement (Auger Muons and Infill for the Ground
Array) of the Pierre Auger Observatory consists of a 23.5 km2
infill area where air shower particles are sampled by water-
Cherenkov detectors at the surface and by 30 m2 scintillation
counters buried 2.3 m underground. The Engineering Array of
AMIGA, completed since February 2015, includes 37 scintillator
modules (290 m2) in a hexagonal layout. In this work, the muon
counting performance of the scintillation detectors is analysed
over the first 20 months of operation. Parametrisations of the
detector counting resolution and the lateral trigger
probability are presented. Finally, preliminary results on the observed muon lateral distribution function (LDF) are discussed.
Ključne besede: Pierre Auger Observatory, AMIGA (Auger Muons and Infill for the Ground Array) muon
counters, muon lateral distribution function (LDF)
Objavljeno v RUNG: 03.03.2016; Ogledov: 5198; Prenosov: 181
Celotno besedilo (499,33 KB) |
