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11.
Temporal and spatial patterns of zinc and iron accumulation during barley (Hordeum vulgare L.) grain development. Journal of agricultural and food chemistry.
Amelie Detterbeck, Paula Pongrac, Daniel Persson, Iztok Arčon, Primož Pelicon, Primož Vaupetič, Mitja Kelemen, Søren Husted, Katarina Vogel-Mikuš, Stephan Clemens, Jan Kofod Shjoerring, 2020, izvirni znanstveni članek

Opis: Breeding and engineering of biofortified crops will benefit from a better understanding of bottlenecks controlling micronutrient loading within the seeds. However, few studies have addressed the changes in micronutrient concentrations, localization, and speciation occurring over time. Therefore, we studied spatial patterns of zinc and iron accumulation during grain development in two barley lines with contrasting grain zinc concentrations. Microparticle-induced-X-ray emission and laser ablationinductively coupled plasma mass spectrometry were used to determine tissue-specific accumulation of zinc, iron, phosphorus, and sulfur. Differences in zinc accumulation between the lines were most evident in the endosperm and aleurone. A gradual decrease in zinc concentrations from the aleurone to the underlying endosperm was observed, while iron and phosphorus concentrations decreased sharply. Iron co-localized with phosphorus in the aleurone, whereas zinc co-localized with sulfur in the sub-aleurone. We hypothesize that differences in grain zinc are largely explained by the endosperm storage capacity. Engineering attempts should be targeted accordingly.
Najdeno v: osebi
Ključne besede: barley (Hordeum vulgare L.), biofortification, grain development, grain loading, LA-ICP-MS, μ-PIXE
Objavljeno: 20.10.2020; Ogledov: 1596; Prenosov: 0
.pdf Polno besedilo (4,76 MB)

12.
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Comparing black-carbon- and aerosol-absorption-measuring instruments – a new system using lab-generated soot coated with controlled amounts of secondary organic matter
Antti-Pekka Hyvärinen, Konstantina Vasilatou, Matthias Oscity, Ernest Weingartner, Bradley Visser, Jannis Röhrbein, Luka Drinovec, Daniel M. Kalbermatter, Griša Močnik, 2022, izvirni znanstveni članek

Opis: We report on an inter-comparison of black-carbon- and aerosol-absorption-measuring instruments with laboratory-generated soot particles coated with controlled amounts of secondary organic matter (SOM). The aerosol generation setup consisted of a miniCAST 5201 Type BC burner for the generation of soot particles and a new automated oxidation flow reactor based on the micro smog chamber (MSC) for the generation of SOM from the ozonolysis of α-pinene. A series of test aerosols was generated with elemental to total carbon (EC  TC) mass fraction ranging from about 90 % down to 10 % and single-scattering albedo (SSA at 637 nm) from almost 0 to about 0.7. A dual-spot Aethalometer AE33, a photoacoustic extinctiometer (PAX, 870 nm), a multi-angle absorption photometer (MAAP), a prototype photoacoustic instrument, and two prototype photo-thermal interferometers (PTAAM-2λ and MSPTI) were exposed to the test aerosols in parallel. Significant deviations in the response of the instruments were observed depending on the amount of secondary organic coating. We believe that the setup and methodology described in this study can easily be standardised and provide a straightforward and reproducible procedure for the inter-comparison and characterisation of both filter-based and in situ black-carbon-measuring (BC-measuring) instruments based on realistic test aerosols.
Najdeno v: osebi
Ključne besede: black carbon, aerosol absorption, secondary organic aerosol, coating
Objavljeno: 01.02.2022; Ogledov: 464; Prenosov: 13
.pdf Polno besedilo (752,94 KB)

14.
A dual-wavelength photothermal aerosol absorption monitor
Konstantina Vasilatou, Griša Močnik, Ernest Weingartner, Daniel M. Kalbermatter, Bradley Visser, Jannis Röhrbein, Luca Ferrero, Kristijan Vidović, Mario Kurtjak, Miha Škarabot, Luka Pirker, Luka Drinovec, Uroš Jagodič, 2022, izvirni znanstveni članek

Opis: There exists a lack of aerosol absorption measurement techniques with low uncertainties and without artefacts. We have developed the two-wavelength Photothermal Aerosol Absorption Monitor (PTAAM-2λ), which measures the aerosol absorption coefficient at 532 and 1064 nm. Here we describe its design, calibration and mode of operation and evaluate its applicability, limits and uncertainties. The 532 nm channel was calibrated with ∼ 1 µmol mol−1 NO2, whereas the 1064 nm channel was calibrated using measured size distribution spectra of nigrosin particles and a Mie calculation. Since the aerosolized nigrosin used for calibration was dry, we determined the imaginary part of the refractive index of nigrosin from the absorbance measurements on solid thin film samples. The obtained refractive index differed considerably from the one determined using aqueous nigrosin solution. PTAAM-2λ has no scattering artefact and features very low uncertainties: 4 % and 6 % for the absorption coefficient at 532 and 1064 nm, respectively, and 9 % for the absorption Ångström exponent. The artefact-free nature of the measurement method allowed us to investigate the artefacts of filter photometers. Both the Aethalometer AE33 and CLAP suffer from cross-sensitivity to scattering – this scattering artefact is most pronounced for particles smaller than 70 nm. We observed a strong dependence of the filter multiple scattering parameter on the particle size in the 100–500 nm range. The results from the winter ambient campaign in Ljubljana showed similar multiple scattering parameter values for ambient aerosols and laboratory experiments. The spectral dependence of this parameter resulted in AE33 reporting the absorption Ångström exponent for different soot samples with values biased 0.23–0.35 higher than the PTAAM-2λ measurement. Photothermal interferometry is a promising method for reference aerosol absorption measurements.
Najdeno v: osebi
Ključne besede: aerosol absorption, calibration, black carbon
Objavljeno: 28.06.2022; Ogledov: 120; Prenosov: 3
.pdf Polno besedilo (2,90 MB)
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