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31.
Quantitative detection of Microcystis aeruginosa in fresh water using single domain antibodies (VHHs)
Ario de Marco, Dorota Korte, Hanna Budasheva, Mladen Franko, Elisa Mazzega, Sandra Folarin Oloketuyi, Gbenga Folorunsho Oginni, published scientific conference contribution abstract

Found in: ključnih besedah
Summary of found: ...thermal lens spectrometry, nanobodies, fluobodies, cyanobacteria...
Keywords: thermal lens spectrometry, nanobodies, fluobodies, cyanobacteria
Published: 18.11.2019; Views: 1057; Downloads: 58
.pdf Fulltext (15,09 KB)

32.
A multi-thermal-lens approach to evaluation of multi-pass probe beam configuration in thermal lens spectrometry
Humberto Cabrera, Leja Goljat, Dorota Korte, Ernesto Marin, Mladen Franko, original scientific article

Abstract: In this work, a recently proposed thermal lens instrument based on multi-pass probe beam concept is investigated and described as a multi-thermal-lens equivalent system. A simulation of the photothermal lens signal formation in a multi-thermal-lens equivalent configuration of the system is performed and validated by comparing the experimental signals of single, dual and ten-pass configurations to theoretically calculated values. The theoretically predicted enhancement of the signal is 9 to 10-fold for a weak thermal lens when comparing the ten-pass configuration with the conventional single-pass thermal lens system. Experimentally achieved signal enhancement in the ten-pass system is 8.3 for pure ethanol sample and between 8 and 9 for solutions with different concentrations of the Fe(II) - 1,10-Phenanthroline complex. Additionally, a value of 9.1 was calculated as the ratio of the slopes of the calibration lines obtained using the ten-pass and single-pass configurations. The achieved limit of detection for determination of Fe(II), in the ten-pass configuration, was 0.4 µgL-1, with a relative standard deviation around 4.5%, which compares favorably with previously reported results for TLS determination of Fe(II) in thin samples using low excitation power. For the multi-pass configuration the linear range of measurement is reduced when compared to the single-pass configuration. This is explained by the theoretical analysis of the photothermal signal under multi-pass condition, which shows the important contribution of the nonlinear term in the theoretical expression for the photothermal signal. The ten-pass configuration, which is presented and validated experimentally for the first time, offers important signal enhancement needed in recently developed TLS instruments with tunable, low power excitation sources.
Found in: ključnih besedah
Keywords: Thermal lens spectrometry, Photothermal detection, Trace determination, Chemical sensor
Published: 10.12.2019; Views: 718; Downloads: 0
.pdf Fulltext (656,75 KB)

33.
Mineral element composition in grain of awned and awnletted wheat (Triticum aestivum L.) cultivars tissue-specific iron speciation and phytate and non-phytate ligand ratio
Hiram Castillo Michel, Iztok Arčon, Paula Pongrac, Katarina Vogel-Mikuš, 2020, original scientific article

Abstract: In wheat (Triticum aestivum L.), the awns—the bristle-like structures extending from lemmas—are photosynthetically active. Compared to awned cultivars, awnletted cultivars produce more grains per unit area and per spike, resulting in significant reduction in grain size, but their mineral element composition remains unstudied. Nine awned and 11 awnletted cultivars were grown simultaneously in the field. With no difference in 1000-grain weight, a larger calcium and manganese—but smaller iron (Fe) concentrations—were found in whole grain of awned than in awnletted cultivars. Micro X-ray absorption near edge structure analysis of different tissues of frozen-hydrated grain cross-sections revealed that differences in total Fe concentration were not accompanied by differences in Fe speciation (64% of Fe existed as ferric and 36% as ferrous species) or Fe ligands (53% were phytate and 47% were non-phytate ligands). In contrast, there was a distinct tissue-specificity with pericarp containing the largest proportion (86%) of ferric species and nucellar projection (49%) the smallest. Phytate ligand was predominant in aleurone, scutellum and embryo (72%, 70%, and 56%, respectively), while nucellar projection and pericarp contained only non-phytate ligands. Assuming Fe bioavailability depends on Fe ligands, we conclude that Fe bioavailability from wheat grain is tissue specific.
Found in: ključnih besedah
Summary of found: ...phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry, phosphorus, sulphur, nicotianamine...
Keywords: biofortification, phytate, iron, awn, X-ray fluorescence, X-ray absorption spectrometry, phosphorus, sulphur, nicotianamine
Published: 16.01.2020; Views: 567; Downloads: 0
.pdf Fulltext (2,63 MB)

34.
Implementation of high performance liquid chromatography coupled to thermal lens spectrometry (HPLC‑TLS) for quantification of pyranoanthocyanins during fermentation of Pinot Noir grapes
Lorena Butinar, Jelena Topič Božič, Natka Ćurko, Karin Kovačević Ganić, Branka Mozetič Vodopivec, Dorota Korte, Mladen Franko, 2020, original scientific article

Abstract: In this work high performance liquid chromatography coupled to thermal lens spectrometry (HPLC-TLS) was applied for monitoring of vinylphenolic pyranoanthocyanins formation during the fermentation of Pinot Noir wines. Vinylphenolic pyranoanthocyanins are wine pigments, present in low concentrations, but very important for wine colour stability. Fermentation process was conducted with four different yeast strains, used as starters, either in sequential fermentation of non-Saccharomyces with S. cerevisiae yeast or as single fermentation with S. cerevisiae yeasts in order to test the applicability of developed method for monitoring of selected compounds in real wine fermentation experiments. The developed HPLC-TLS method showed higher sensitivity compared to HPLC coupled to diode array detection (DAD) technique for particular wine colour compounds. Obtained limits of detection (LODs), were 6- and 22-times lower in comparison to HPLC–DAD in gradient and isocratic elution mode, respectively, whereas limits of quantification (LOQs) 5 and 18-times lower. Lower LODs enabled earlier observation of vinylphenolic pyranoanthocyanins formation during fermentation (already at day 7) in the case of HPLC-TLS method in gradient mode, while by using HPLC–DAD in gradient elution mode the formation of vinylphenolic pyranoanthocyanins was noticed only after 12 days of fermentation.
Found in: ključnih besedah
Keywords: Thermal lens spectrometry (TLS), High performance liquid chromatography (HPLC), Pyranoanthocyanins, Wine, Yeasts
Published: 18.06.2020; Views: 442; Downloads: 0
.pdf Fulltext (1,94 MB)

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