Inta Kalnina - Academia.edu (original) (raw)
Papers by Inta Kalnina
Journal of physics, 2023
Physical vapor deposition (PVD) of metallic thin films is used extensively in the fabrication of ... more Physical vapor deposition (PVD) of metallic thin films is used extensively in the fabrication of semiconductor technology devices - use as of lately for them have grown. Tungsten (W) is a low resistivity, refractory metal, that is often deposited by PVD methods for use as a gate contact to semiconductor devices and due to the low work function and high thermal stability, W can be used for the fabrication of field emitters in microelectronics [1-3]. In order to monitor quality of the synthesized thin films by magnetron sputtering method, it is necessary to develop methodology suitable for the analysis of these thin films. Infrared spectrometry is a sensitive method for the analysis of chemical bonds, but W thin films contain weakly polar and non-polar W-W bonds, that cannot be directly detected by infrared spectrometry, therefore oxidation of W is selected as thermal oxidation method for detecting oxidized products for thin films of thickness 150 nm, for instance, W-O bonds. After oxidation, it was observed, that the oxidation of W thin films takes place already at a 600 °C in the air atmosphere. The Fourier transform infrared spectrometry (FTIR) spectra of modified coatings showed formation of additional new signals in the region of 700-900 cm−1 attributed to W-O, O-W-O, W=O bonds - formation of W-oxygen bonds on Si-SiO2 substrate was achieved. For coating homogeneity and production quality formation, additionally synthesized control samples are recommended for FTIR analysis.
Journal of Nuclear Materials, 2009
Beryllium pebbles and tiles will be used as neutron multiplier and as plasma facing material, res... more Beryllium pebbles and tiles will be used as neutron multiplier and as plasma facing material, respectively, in future fusion reactors and will be subjected to action of radiation, temperature, electric and magnetic fields (MF) simultaneously. Tritium is generated in beryllium by its reactions with neutrons and by action of plasma under operation conditions of the reactor and will accumulate in both the beryllium articles-pebbles and tiles. The tritium retention may cause fuel problems and environmental hazard. Tritium release at thermo-annealing of the beryllium pebbles irradiated in the BERYLLIUM and EXOTIC experiments, and the beryllium tiles from JET (exposed to D+D, D+T plasma) was investigated in temperature programmed experiments both without and in magnetic field of 2.35 T, and at a constant temperature under 5 MeV fast electron radiation of the dose rate 14 MGy/h and in magnetic field of 1.7 T separately and simultaneously in order to evaluate possible effects of these factors. Also, tritium sorption and desorption of unused beryllium tiles were investigated to evaluate action of radiation and magnetic field. Chemical forms of tritium and their distribution were determined in the beryllium samples with lyomethods. Chemical forms of tritium in the beryllium pebbles and tiles both not treated and treated are similar-T2, T+, T • , but their abundances and their distribution are different in the volume of the samples. MF influence on the tritium release from differently irradiated beryllium pebbles and tiles is slightly different. Irradiation with fast electrons facilitated the process of tritium release, but all three factors together considerably increased the tritium release at thermoannealing. Irradiation with fast electrons stimulated thermo-sorption of tritium about 0.1 Pa at 773 K for 3 h in unused beryllium tiles, but the simultaneous action of magnetic field and radiation did not change sorption. The simultaneous action of radiation and magnetic field increased the tritium desorption at 773 K for 0.5 h by a factor of 6.
International Journal of Low Radiation, Mar 20, 2015
ABSTRACT Around 6000 inhabitants (20-49 years old in 1986) of Latvia took part in clean-up work i... more ABSTRACT Around 6000 inhabitants (20-49 years old in 1986) of Latvia took part in clean-up work in Chernobyl from 1986 till 1991. Most of them were officially documented as recipients of ionising radiation exposure (1-50 cGy). ABM (a 3-aminobenzanthrone derivative developed at the Riga Technical University, Riga, Latvia) has been previously shown to be a potential probe for determining the immune state of patients with different pathologies. The first study (using ABM) of Peripheral Blood Mononuclear Cell (PBMC) membranes of Chernobyl clean-up workers (n-97) from Latvia was conducted in 1996-1997. In 2006-2007 we examined the same (n = 54) individuals. Lipid peroxidation, ABM and ANS spectral parameters in PBMC suspension, fluorescence anisotropy and blood plasma albumin characteristics were recorded. In 1997 screening showed five different patterns of fluorescence spectra, but in 2007 we obtained only four. These patterns of spectra had never been seen previously in healthy individuals or patients with tuberculosis, multiple sclerosis, rheumatoid arthritis, etc., examined by us. The patterns of ABM fluorescence spectra were associated with membrane anisotropy and conformational changes of blood plasma albumin. It is necessary to note that all investigated parameters significantly differed in the observed groups of patients. These findings reinforce our understanding that the cell membrane is a significant biological target of radiation. These studies reveals a progressive trend towards certain resemblances to PBMC membranes of chronic B-cell lymphoid leukaemia and protein coformational alterations.
Biologicheskie membrany
ABSTRACT
Arkhiv patologii
To evaluate the possible antitumour effect of intensified deposition of serotonin in the region o... more To evaluate the possible antitumour effect of intensified deposition of serotonin in the region of localization of the tumour caused by a pharmacological preparation studies of the effect of inhibitors of monoamine oxidase transamine and N2N2-dibenzylhydrazide of DL-malic acid on rat's cerebellum tumour de-differentiated by astrocytoma (strain No 101/12) were carried out. The effect of inhibitors of monoamine oxidase was compared with that of antiblastic preparation of phthorafur. Differences in the mechanisms of action of pharmacological agents referred to above are shown. It was established that inhibitors of monoamine oxidase administered against the background of the developing tumour caused a considerable reduction in its weight and prononced dystrophic and necrotic changes.
We report the results on the spectroscopic properties of a new fluorescent lipophilic probes. Bas... more We report the results on the spectroscopic properties of a new fluorescent lipophilic probes. Basic photophysical characteristics of the novel benzanthrone 3amino-derivatives such as the absorption and fluorescence maxima, extinction coefficient, Stokes shift, fluorescence intensity were measured in benzene, chloroform and ethanol solutions. Novel benzanthrone 3-N-derivatives show bright fluorescence and are quite sensitive to the surrounding environment. The behaviour of the investigated benzanthrone derivatives was dependent on the polarity of the medium showing strong fluorescent solvatochromism arising from the donor-acceptor nature of the benzanthrone carbonyl group and electron-rich substituted amino group.
Impact of hydrodynamic stress on microorganisms is very complicated, because in bioreactors with ... more Impact of hydrodynamic stress on microorganisms is very complicated, because in bioreactors with mixing systems stirring conditions are different at various points of the reactor. There are zones with extremely high stirring intensity, where mycelial and other shear sensitive cells can be damaged, while in less intensive zones the mass transfer rate is insufficient. Considering this counterflow mixing systems, which maintain practically even distribution of the introduced power in the whole volume of bioreactor were used. The objective of the study was investigation of physiological and biochemical changes in microbial populations ( eucaryotes and procaryotes ) caused by physical, chemical and mechanical impact of stirring intensity. It has been established that the excess turbulence created by high stirring intensity results in inhibition of microbial growth and metabolism. Significant increase of biologically active amine - histamine concentration in cells with increasing stirring...
International Journal of Low Radiation
International Journal of Low Radiation, 2010
... 7, No. 5, 2010 409 Copyright © 2010 Inderscience Enterprises Ltd. Antioxidant therapy and its... more ... 7, No. 5, 2010 409 Copyright © 2010 Inderscience Enterprises Ltd. Antioxidant therapy and its stability on Chernobyl clean-up workers Andrejs Skesters Laboratory of Biochemistry, Riga Stradins University, Riga, Latvia Email: Andrejs.Skesters@rsu.lv Tija Zvagule ...
The use of a newly synthesized fluorescent probe, ABM (conditional name), to determine changes of... more The use of a newly synthesized fluorescent probe, ABM (conditional name), to determine changes of membrane composition (fluidity), biomass yield, ethanol productivity, and yield of Zymomonas mobilis under anaerobic conditions was investigated. A strong correlation between ABM spectral characteristics in cell suspension and all obtained parameters was observed. It was concluded that application of ABM is a useful tool to detect temperature-induced changes in the membrane composition of Zymomonas mobilis.
Journal of Experimental and Integrative Medicine, 2011
Journal of Experimental and Integrative Medicine, 2012
Journal of Experimental and Integrative Medicine, 2012
Journal of Experimental and Integrative Medicine, 2014
Journal of physics, 2023
Physical vapor deposition (PVD) of metallic thin films is used extensively in the fabrication of ... more Physical vapor deposition (PVD) of metallic thin films is used extensively in the fabrication of semiconductor technology devices - use as of lately for them have grown. Tungsten (W) is a low resistivity, refractory metal, that is often deposited by PVD methods for use as a gate contact to semiconductor devices and due to the low work function and high thermal stability, W can be used for the fabrication of field emitters in microelectronics [1-3]. In order to monitor quality of the synthesized thin films by magnetron sputtering method, it is necessary to develop methodology suitable for the analysis of these thin films. Infrared spectrometry is a sensitive method for the analysis of chemical bonds, but W thin films contain weakly polar and non-polar W-W bonds, that cannot be directly detected by infrared spectrometry, therefore oxidation of W is selected as thermal oxidation method for detecting oxidized products for thin films of thickness 150 nm, for instance, W-O bonds. After oxidation, it was observed, that the oxidation of W thin films takes place already at a 600 °C in the air atmosphere. The Fourier transform infrared spectrometry (FTIR) spectra of modified coatings showed formation of additional new signals in the region of 700-900 cm−1 attributed to W-O, O-W-O, W=O bonds - formation of W-oxygen bonds on Si-SiO2 substrate was achieved. For coating homogeneity and production quality formation, additionally synthesized control samples are recommended for FTIR analysis.
Journal of Nuclear Materials, 2009
Beryllium pebbles and tiles will be used as neutron multiplier and as plasma facing material, res... more Beryllium pebbles and tiles will be used as neutron multiplier and as plasma facing material, respectively, in future fusion reactors and will be subjected to action of radiation, temperature, electric and magnetic fields (MF) simultaneously. Tritium is generated in beryllium by its reactions with neutrons and by action of plasma under operation conditions of the reactor and will accumulate in both the beryllium articles-pebbles and tiles. The tritium retention may cause fuel problems and environmental hazard. Tritium release at thermo-annealing of the beryllium pebbles irradiated in the BERYLLIUM and EXOTIC experiments, and the beryllium tiles from JET (exposed to D+D, D+T plasma) was investigated in temperature programmed experiments both without and in magnetic field of 2.35 T, and at a constant temperature under 5 MeV fast electron radiation of the dose rate 14 MGy/h and in magnetic field of 1.7 T separately and simultaneously in order to evaluate possible effects of these factors. Also, tritium sorption and desorption of unused beryllium tiles were investigated to evaluate action of radiation and magnetic field. Chemical forms of tritium and their distribution were determined in the beryllium samples with lyomethods. Chemical forms of tritium in the beryllium pebbles and tiles both not treated and treated are similar-T2, T+, T • , but their abundances and their distribution are different in the volume of the samples. MF influence on the tritium release from differently irradiated beryllium pebbles and tiles is slightly different. Irradiation with fast electrons facilitated the process of tritium release, but all three factors together considerably increased the tritium release at thermoannealing. Irradiation with fast electrons stimulated thermo-sorption of tritium about 0.1 Pa at 773 K for 3 h in unused beryllium tiles, but the simultaneous action of magnetic field and radiation did not change sorption. The simultaneous action of radiation and magnetic field increased the tritium desorption at 773 K for 0.5 h by a factor of 6.
International Journal of Low Radiation, Mar 20, 2015
ABSTRACT Around 6000 inhabitants (20-49 years old in 1986) of Latvia took part in clean-up work i... more ABSTRACT Around 6000 inhabitants (20-49 years old in 1986) of Latvia took part in clean-up work in Chernobyl from 1986 till 1991. Most of them were officially documented as recipients of ionising radiation exposure (1-50 cGy). ABM (a 3-aminobenzanthrone derivative developed at the Riga Technical University, Riga, Latvia) has been previously shown to be a potential probe for determining the immune state of patients with different pathologies. The first study (using ABM) of Peripheral Blood Mononuclear Cell (PBMC) membranes of Chernobyl clean-up workers (n-97) from Latvia was conducted in 1996-1997. In 2006-2007 we examined the same (n = 54) individuals. Lipid peroxidation, ABM and ANS spectral parameters in PBMC suspension, fluorescence anisotropy and blood plasma albumin characteristics were recorded. In 1997 screening showed five different patterns of fluorescence spectra, but in 2007 we obtained only four. These patterns of spectra had never been seen previously in healthy individuals or patients with tuberculosis, multiple sclerosis, rheumatoid arthritis, etc., examined by us. The patterns of ABM fluorescence spectra were associated with membrane anisotropy and conformational changes of blood plasma albumin. It is necessary to note that all investigated parameters significantly differed in the observed groups of patients. These findings reinforce our understanding that the cell membrane is a significant biological target of radiation. These studies reveals a progressive trend towards certain resemblances to PBMC membranes of chronic B-cell lymphoid leukaemia and protein coformational alterations.
Biologicheskie membrany
ABSTRACT
Arkhiv patologii
To evaluate the possible antitumour effect of intensified deposition of serotonin in the region o... more To evaluate the possible antitumour effect of intensified deposition of serotonin in the region of localization of the tumour caused by a pharmacological preparation studies of the effect of inhibitors of monoamine oxidase transamine and N2N2-dibenzylhydrazide of DL-malic acid on rat's cerebellum tumour de-differentiated by astrocytoma (strain No 101/12) were carried out. The effect of inhibitors of monoamine oxidase was compared with that of antiblastic preparation of phthorafur. Differences in the mechanisms of action of pharmacological agents referred to above are shown. It was established that inhibitors of monoamine oxidase administered against the background of the developing tumour caused a considerable reduction in its weight and prononced dystrophic and necrotic changes.
We report the results on the spectroscopic properties of a new fluorescent lipophilic probes. Bas... more We report the results on the spectroscopic properties of a new fluorescent lipophilic probes. Basic photophysical characteristics of the novel benzanthrone 3amino-derivatives such as the absorption and fluorescence maxima, extinction coefficient, Stokes shift, fluorescence intensity were measured in benzene, chloroform and ethanol solutions. Novel benzanthrone 3-N-derivatives show bright fluorescence and are quite sensitive to the surrounding environment. The behaviour of the investigated benzanthrone derivatives was dependent on the polarity of the medium showing strong fluorescent solvatochromism arising from the donor-acceptor nature of the benzanthrone carbonyl group and electron-rich substituted amino group.
Impact of hydrodynamic stress on microorganisms is very complicated, because in bioreactors with ... more Impact of hydrodynamic stress on microorganisms is very complicated, because in bioreactors with mixing systems stirring conditions are different at various points of the reactor. There are zones with extremely high stirring intensity, where mycelial and other shear sensitive cells can be damaged, while in less intensive zones the mass transfer rate is insufficient. Considering this counterflow mixing systems, which maintain practically even distribution of the introduced power in the whole volume of bioreactor were used. The objective of the study was investigation of physiological and biochemical changes in microbial populations ( eucaryotes and procaryotes ) caused by physical, chemical and mechanical impact of stirring intensity. It has been established that the excess turbulence created by high stirring intensity results in inhibition of microbial growth and metabolism. Significant increase of biologically active amine - histamine concentration in cells with increasing stirring...
International Journal of Low Radiation
International Journal of Low Radiation, 2010
... 7, No. 5, 2010 409 Copyright © 2010 Inderscience Enterprises Ltd. Antioxidant therapy and its... more ... 7, No. 5, 2010 409 Copyright © 2010 Inderscience Enterprises Ltd. Antioxidant therapy and its stability on Chernobyl clean-up workers Andrejs Skesters Laboratory of Biochemistry, Riga Stradins University, Riga, Latvia Email: Andrejs.Skesters@rsu.lv Tija Zvagule ...
The use of a newly synthesized fluorescent probe, ABM (conditional name), to determine changes of... more The use of a newly synthesized fluorescent probe, ABM (conditional name), to determine changes of membrane composition (fluidity), biomass yield, ethanol productivity, and yield of Zymomonas mobilis under anaerobic conditions was investigated. A strong correlation between ABM spectral characteristics in cell suspension and all obtained parameters was observed. It was concluded that application of ABM is a useful tool to detect temperature-induced changes in the membrane composition of Zymomonas mobilis.
Journal of Experimental and Integrative Medicine, 2011
Journal of Experimental and Integrative Medicine, 2012
Journal of Experimental and Integrative Medicine, 2012
Journal of Experimental and Integrative Medicine, 2014