This paper presents modelling results on the RBMK-1500 reactor water purification and cooling system (PCS) components contamination at Ignalina NPP Unit 1. The modelling was performed using a ...computer code LLWAA-DECOM (Tractebel Energy Engineering, Belgium), taking into consideration PCS components characteristics, parameters of the water flowing in circuits, system work regimes, and so forth. During the modelling, results on activity of PCS subsystems and components’ deposits and nuclide composition of deposits at the moment of the final shutdown of the reactor, as well as activity decay of the most contaminated PCS components’ deposits and dose rates after the final shutdown of the reactor, were obtained. Significant difference of contamination levels was revealed among PCS subsystems and subsystems components. The subsystem of nonpurified water is the most contaminated in PCS, and the activity of the least contaminated component in this subsystem is only 1.42% compared to the activity of the most contaminated component. The most contaminated and the least contaminated components of the purified water subsystem comprise 28.33% and 0.86% of activity, respectively, compared to the activity of the most contaminated PCS component.
A hyphenated LC-DAD-SPE-NMR setup in combination with on-line radical scavenging detection has been applied for the identification of radical scavenging compounds in extracts of ...Rhaponticumcarthamoides. After NMR measurements, the pure compounds were infused into a mass spectrometer. The technique enabled selective detection and identification of individual radical scavenging compounds without any prior off-line chromatographic steps. Seven compounds, namely, quercetagetin-7-beta-glucopyranoside (1), quercetagetin-7-(6"-acetyl-beta-glucopyranoside) (3), 6-hydroxykaempferol-7-beta-glucopyranoside (2), 6-methoxykaempferol-3-beta-glucopyranoside (4), 6-hydroxykaempferol-7-(6"-acetyl-beta-glucopyranoside) (5), chlorogenic acid (6), and beta-ecdysone (7), were identified in ethanol or aqueous extracts. Compound 5 is a new natural compound. Its radical scavenging activity was tested against DPPH radical and was found to be weaker than that of the reference antioxidants rosmarinic acid and Trolox.
Antioxidant activity of Potentilla fruticosa Miliauskas, G; Beek, T.A. van; Venskutonis, P.R ...
Journal of the science of food and agriculture,
December 2004, Letnik:
84, Številka:
15
Journal Article
Recenzirano
The molecular structures of the radical scavenging compounds present in extracts of Potentilla fruticosa blossoms were elucidated and the antioxidant activities of various extracts were determined. ...The activities of the different fractions were monitored by off-line and on-line RP-HPLC DPPH ̇and ABTS+̇ scavenging methods. Twelve compounds were isolated and identified, namely ellagic acid, catechin, quercetin-3-beta-glucopyranoside, quercetin-3-beta-galactopyranoside, quercetin-3-beta-rutinoside, quercetin-3-beta-glucuronopyranoside, quercetin-3-beta-arabinofuranoside, kaempferol-3-beta-rutinoside, kaempferol-3-O-beta-(6-O-(E)-p-coumaroyl)glucopyranoside, rhamnetin-3-beta-glucopyranoside and rhamnetin-3-beta-galactopyranoside. The radical scavenging activity of each isolated compound was measured using DPPH ̇and ABTS+̇ assays and compared with the activity of rosmarinic acid. Catechin and ellagic acid were found to be the most active radical scavengers. The antioxidant properties of plant fractions were assessed in model systems by measuring superoxide anion and hydrogen peroxide scavenging, beta-carotene bleaching, hexanal production in edible oil, peroxide formation, and the increase in UV absorbance in the course of oxidation.
Antioxidative properties of
Geranium macrorrhizum,
Potentilla fruticosa and
Rosmarinus officinalis (as a reference) extracts were evaluated in Dutch style fermented sausages. Extracts were ...incorporated into sausages during preparation. The sausages were subsequently fermented, tested and compared to a standard spices mix, traditionally used for the production of such sausages. Formation of the primary oxidation products – peroxides, and secondary – TBARS and hexanal was monitored. The polar extracts from
Potentilla showed some antioxidant activity, especially in combination with ascorbate, however the activity was low compared to the standard spices mix. Polar extracts from
Geranium showed only negligible antioxidant activity.
Antioxidative activity of Geranium macrorrhizum MILIAUSKAS, Giedrius; VAN BEEK, Teris A; VENSKUTONIS, Petras R ...
European food research & technology,
02/2004, Letnik:
218, Številka:
3
Journal Article
Recenzirano
The composition of radical-scavenging compounds from Geranium macrorrhizum leaves was analyzed and the antioxidative activities of various extracts was determined. Seven compounds, namely gallic ...acid, ellagic acid, 4-galloyl quinic acid, the flavonoid quercetin and three of its glycosides, quercetin-3-β-glucopyranoside, quercetin-3-β-galactopyranoside and quercetin-4'-β-glucopyranoside were isolated and identified in the various fractions. The radical-scavenging activity of the isolated compounds was measured using DPPH^sup ·^ and ABTS^sup ·+^ scavenging assays and compared with the activity of rosmarinic acid. Quercetin-3-glucopyranoside and quercetin-3-galactopyranoside showed the highest antioxidative capacities. Antioxidative activities of all plant fractions were assessed by model system tests (superoxide anion and hydrogen peroxide scavenging) and by oxidation tests (β-carotene bleaching, peroxide value, UV absorbance and headspace-gas chromatography hexanal determination). The ethanol-butanol fraction of the plant possessed the highest activity in most of the tests.PUBLICATION ABSTRACT
The application of analytical and semi-preparative columns in reversed-phase liquid chromatography–solid-phase extraction–nuclear magnetic resonance (HPLC-SPE-NMR) was compared. The work was aiming ...at separating a higher sample amount in a single run and in this way to reduce the necessary NMR measurement time of separated compounds. Several parameters for compound separation and trapping procedures were optimised: flow rate of HPLC and make-up water pumps, choice of stationary phase cartridges and drying time. The separation and loadability of nine model compounds on analytical and semi-preparative columns was determined, as well as the focussing capacity of SH-type SPE cartridges. It was found that a semi-preparative column—or multiple peak trapping on analytical columns—gave better results than a standard 4.6
mm analytical column for non-polar compounds (e.g. flavonoid aglycones, sesquiterpene lactones, non-polar terpenes, log
P
>
2), but for polar compounds (log
P
<
−2) did not offer any advantage over an analytical column, or was even disadvantageous. For intermediately polar compounds (−2
<
log
P
<
2) this has to be investigated per compound.
Glomus tumours occur in many sites. We report the first case of a glomangiomyoma in the pancreas of a 17-year-old girl. The tumour was 5cm in diameter and consisted of rounded glomus cells, blood ...vessels and spindled smooth muscle cells. The glomus and smooth muscle tumour cells showed moderate diffuse cytoplasmic staining with vimentin, muscle-specific actin and smooth muscle actin. There was weak focal positivity for desmin in the spindle cell component only. The patient is alive and well with no evidence of recurrence 24 months after surgery.
The application of analytical and semi-preparative columns in reversed-phase liquid chromatography-solid-phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) was compared. The work was aiming ...at separating a higher sample amount in a single run and in this way to reduce the necessary NMR measurement time of separated compounds. Several parameters for compound separation and trapping procedures were optimised: flow rate of HPLC and make-up water pumps, choice of stationary phase cartridges and drying time. The separation and loadability of nine model compounds on analytical and semi-preparative columns was determined, as well as the focussing capacity of SH-type SPE cartridges. It was found that a semi-preparative column-or multiple peak trapping on analytical columns-gave better results than a standard 4.6mm analytical column for non-polar compounds (e.g. flavonoid aglycones, sesquiterpene lactones, non-polar terpenes, logP>2), but for polar compounds (logP
In the present paper, referring to known characteristics of the outer hair cells functioning in the cochlea of the inner ear, a functional model of the outer hair cells is constructed. It consists of ...a linear feed-forward circuit and a non-linear positive feedback circuit. The feed-forward circuit reflects the contribution of local basilar and tectorial membrane areas and passive outer hair cells’ physical parameters to the forming of low-selectivity resonance characteristics. The non-linear positive feedback circuit reflects the non-linear outer hair cell signal transduction processes and the active role of efferents from the medial superior olive in altering circuit sensitivity and selectivity.
Referring to an analytical description of the circuit model and computer simulation results, an explanation is given over the biological meaning of the outer hair cells’ non-linearities in signal transduction processes and the role of the non-linearities in achieving the following: signal compression, the dependency of circuit sensitivity and frequency selectivity upon the input signal amplitude, the compatibility of high-frequency selectivity and short transient response of the biological filtering circuits.
An adaptive nonlinear signal-filtering model of the cochlea is proposed based on the functional properties of the inner ear. The model consists of the cochlear filtering segments taking into account ...the longitudinal, transverse and radial pressure wave propagation.
On the basis of an analytical description of different parts of the model and the results of computer modeling, the biological significance of the nonlinearity of signal transduction processes in the outer hair cells, their role in signal compression and adaptation, the efferent control over the characteristics of the filtering structures (frequency selectivity and sensitivity) are explained.
PDF
