51. On spin description of water-biopolymer interactions: theory and experiment of reentrant order-disorder transition.Artem Badasyan, predavanje na tuji univerzi Opis: The experimental studies of biopolymer conformations have reached an unprecedented level of
detailization during the past decade and allow now to study single molecules in vivo [1]. Processing of
experimental data essentially relies on theoretical approaches to conformational transitions in
biopolymers [2]. However, the models that are currently used, originate from the early 1960's and
contain several unjustified assumptions, widely accepted at that time. Thus, the view on the
conformational transitions in the polypeptides as a two-state process has very limited applicability
because the all-or-none transition mechanism takes place only in short polypeptides with sizes
comparable to the spatial correlation length; the original formulation of Zimm-Bragg model is
phenomenological and does not allow for a microscopic model for water; the implicit consideration of
the water-polypeptide interactions through the ansatz about the quadratic dependence of free energy
difference on temperature can only be justified through the assumption of an ideal gas with a constant
heat capacity. To get rid of these deficiencies, we augment the Hamiltonian formulation [3] of the
Zimm-Bragg model [4] with the term describing the water-polypeptide interactions [5]. The analytical
solution of the model results in a formula, ready to be fit to Circular Dichroism (CD) data for both heat
and cold denaturation. On the example of several sets of experimental data we show, that our formula
results in a significantly better fit, as compared to the existing approaches. Moreover, the application
of our procedure allows to compare the strengths of inter- and intra-molecular H-bonds, an
information, inaccessible before.
Ključne besede: helix-coil transition, water-polypeptide interactions
Objavljeno v RUNG: 13.03.2019; Ogledov: 3142; Prenosov: 0
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52. Optimization of DGT technique for determination of iron species in natural water and sediments by photothermal beam deflection spectroscopyHanna Budasheva, Arne Bratkič, Dorota Korte, Mladen Franko, 2018, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: beam deflection spectroscopy, diffusive gradients in thin-film technique, iron redox species, photothermal techniques, natural water, sediments
Objavljeno v RUNG: 23.11.2018; Ogledov: 3736; Prenosov: 0
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55. Arsenic in natural waters: hydrogeochemistry characterization and toxicity effectsDoroteja Gošar, 2018, magistrsko delo Opis: Arsenic contamination in natural water is a worldwide problem and a major health concern. In master thesis hydrogeochemistry and toxicity effects of natural waters rich in arsenic were studied. The main objective of the master thesis was to evaluate As pollution of the Freixeda stream and groundwater in abandoned Freixeda gold mine area in NE Portugal near Mirandela city (41.413767 N 7.103562 W) and compare it with the data from previous studies. Further on, toxicological evaluation of selected water samples was performed in the in vitro system of human cell line Caco-2.
Chemical analyses of sampled water samples with use of different modelling sofware show that groundwater have higher sulphate and bicarbonate values than surface water, which could be the reason for As desorption and higher As values in groundwater. Water-rock interaction promotes reduction and dissolution of sulphide minerals and in reductive environments dissolution of secondary Fe minerals releases adsorbed As into solution.
Toxicological testing on human cells included cytotoxicity assay, genotoxicity assay and production of reactive oxigene species (ROS). Genotoxicity was only modestly affected by a short-term exposure to As-contaminated water samples, however, higher concentrations of As in real samples lead to higher level of oxidative stress and decreased cell viability. Exposure of cells to pure As(III) solution show clear concentration dependent decrease in cell metabolism and viability, strong genotoxicity and increased ROS generation.
Considering the worldwide extent of As contamination in natural waters and ability of intestinal epithelium to reduce the potential harmful effects of As, more studies evaluating the human intestinal permeability for As should be done in the future.
Ključne besede: Water quality, arsenic, hydrogeochemistry, toxicity, Caco-2 cell line
Objavljeno v RUNG: 26.09.2018; Ogledov: 5332; Prenosov: 197
 Celotno besedilo (3,76 MB) |
56. Synthesis of molybdenum carbide thin films for production of hydrogen via electrochemical water splitting : M. Sc. thesisCesur Altinkaya, 2018, magistrsko delo Ključne besede: molybdenum, platinum, molybdenum carbide thin films, hydrogen evolution reaction, water splitting, electrolysis, electrochemistry, pyrolysis, thin films
Objavljeno v RUNG: 30.08.2018; Ogledov: 4870; Prenosov: 0
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59. Absorption Spectra of Ethanol and Water Using a Photothermal Lens SpectrophotometerHumberto Cabrera, Jehan Akbar, Dorota Korte, Imrana Ashraf, Evelio E. Ramírez- Miquet, Ernesto Marin, Joseph Niemela, 2018, izvirni znanstveni članek Ključne besede: Thermal lens spectrometry, TLS, absorption of water, absorption of ethanol, vibration overtones
Objavljeno v RUNG: 08.06.2018; Ogledov: 4313; Prenosov: 0
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