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Wyszukujesz frazę "free iron" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Cation exchange capacity of clay rich soils in relation to mineralogical composition and organic matter content
Autorzy:
Dabkowska-Naskret, H
Jaworska, H.
Kobierski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1450278.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
organic matter
capacity
clay rich soil
mineralogical composition
aluminium oxide
soil component
clay fraction
manganese oxide
soil
cation exchange
whole soil
free iron
terrestrial ecosystem
Opis:
Contribution of clay mineral phase (<2 um) and organic matter to the cation exchange capacity (CEC) of two clayey soils (gleyic black earths from Gniew) was investigated. The XRD analysis showed dominance of illite and mixed laver illite/smectite as well as the presence of smectite, chlorite and trace of kaolinite in the clay fraction of studied soils. CEC of the soils ranged between 22.08-32.64 cmol(+)/kg. After removal of organic matter with 30% H2O2, CEC the above values decreased significantly. However, the CEC of organic and inorganic components is not an additive. This may be explained by the formation of organo-mineral complexes, which might lower the CEC of the soil as a whole.
Źródło:
Acta Agrophysica; 2001, 50; 113-118
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generation of ·OH initiated by interaction of Fe2+ and Cu+ with dioxygen; comparison with the Fenton chemistry.
Autorzy:
Urbański, Norbert
Beręsewicz, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1044216.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
superoxide dismutase
autoxidation
catalase
free radical
Fenton reaction
hydroxyl radical
iron ions
copper ions
desferrioxamine
Opis:
Iron and copper toxicity has been presumed to involve the formation of hydroxyl radical (·OH) from H2O2 in the Fenton reaction. The aim of this study was to verify that Fe2+-O2 and Cu+-O2 chemistry is capable of generating ·OH in the quasi physiological environment of Krebs-Henseleit buffer (KH), and to compare the ability of the Fe2+-O2 system and of the Fenton system (Fe2+ + H2O2) to produce ·OH. The addition of Fe2+ and Cu+ (0-20 μM) to KH resulted in a concentration-dependent increase in ·OH formation, as measured by the salicylate method. While Fe3+ and Cu2+ (0-20 μM) did not result in ·OH formation, these ions mediated significant ·OH production in the presence of a number of reducing agents. The ·OH yield from the reaction mediated by Fe2+ was increased by exogenous Fe3+ and Cu2+ and was prevented by the deoxygenation of the buffer and reduced by superoxide dismutase, catalase, and desferrioxamine. Addition of 1 μM, 5 μM or 10 μM Fe2+ to a range of H2O2 concentrations (the Fenton system) resulted in a H2O2-concentration-dependent rise in ·OH formation. For each Fe2+ concentration tested, the ·OH yield doubled when the ratio [H2O2]:[Fe2+] was raised from zero to one. In conclusion: (i) Fe2+-O2 and Cu+-O2 chemistry is capable of promoting ·OH generation in the environment of oxygenated KH, in the absence of pre-existing superoxide and/or H2O2, and possibly through a mechanism initiated by the metal autoxidation; (ii) The process is enhanced by contaminating Fe3+ and Cu2+; (iii) In the presence of reducing agents also Fe3+ and Cu2+ promote the ·OH formation; (iv) Depending on the actual [H2O2]:[Fe2+] ratio, the efficiency of the Fe2+-O2 chemistry to generate ·OH is greater than or, at best, equal to that of the Fe2+-driven Fenton reaction.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 951-962
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Association between body iron stores and level of oxidatively modified DNA bases
Autorzy:
Dziaman, T.
Jurgowiak, M.
Olinski, R.
Powiązania:
https://bibliotekanauki.pl/articles/80695.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
atherosclerosis
cancer
cardiovascular disease
cellular DNA
free radical damage
heterozygosity
iron deficiency anaemia
labile iron pool
oxidative damage
oxidative stress
reactive oxygen species
vascular disease
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2011, 92, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic analysis of cast irons solidification with various types of graphite
Autorzy:
Elbel, T.
Hampl, J.
Powiązania:
https://bibliotekanauki.pl/articles/380412.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pomiar aktywności tlenu
energia swobodna Gibbsa
krzepnięcie żeliwa
continuous oxygen activity measurement
calculation of Gibbs free energy
cast iron solidification
Opis:
The contribution summarises the results of oxygen activity determinations, which were measured and registered continuously in castings from cast irons with various types of graphite. The results were used to find the relationship between two variables: natural logarithm of oxygen activities and reverse value of thermodynamic temperature 1 /T. Obtained regression lines were used to calculate oxygen activity at different temperatures, to calculate Gibbs free energy \deltaG at the different temperatures and to calculate the single \deltaG value for significant temperature of the graphite solidification. The results were processed by a statistical analysis of data files for the different types of graphite with flake, vermicular and spheroidal graphite. Each material has its proper typical oxygen activities range and individual temperature function of Gibbs free energy for analysing and governing casting quality.
Źródło:
Archives of Foundry Engineering; 2012, 12, 4; 157-165
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Cast Iron Modification on Free Vibration Frequency of Casting
Autorzy:
Konopka, Z.
Łągiewka, M.
Zyska, A.
Powiązania:
https://bibliotekanauki.pl/articles/383158.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gray cast iron
modification process
free vibration
casting
vibration frequency of casting
żeliwo szare
proces modyfikacji
drgania swobodne
odlewy
częstotliwość drgań odlewu
Opis:
The paper presents the results of investigations concerning the influence of gray cast iron modification on free vibration frequency of the disc casting. Three different chemical composition melts of gray cast iron were prepared in induction furnace. During gravity casting 0.05% and 0.3% mass of the Inolate modifier was added on stream of metal for changing graphite flakes in castings. Sound signal vibration of cast iron sample was registered by means on microphone for free vibration frequency measurements. Decreasing of free vibration frequency of modified cast iron in comparison with non modified castings was observed. Higher contents of modifier causes more decreasing of free vibration frequency. Cast iron with smaller contents of carbon and silicon have higher free vibration frequency in comparison with eutectic composition cast iron. Hardness of examined cast iron is lower when the more modifier is added during modification process. Free frequency is smaller with smaller Brinell hardness of disc casting. It was concluded that control of free vibration frequency of disc castings by means of chemical composition and modification process can improved comfort and safety of working parts.
Źródło:
Archives of Foundry Engineering; 2020, 20, 1; 23-26
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of iron in pathogenesis of Parkinson disease
Autorzy:
Galazka-Friedman, J.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/80638.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cell membrane
electron microscopy
ELISA test
ferritin
free radical
human brain
iron
lipid peroxidation
liver
neurodegeneration
oxidative stress
Parkinson's disease
pathogenesis
substantia nigra
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2011, 92, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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