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PubMed2001

[Microbial reduction ability of various iron oxides in pure culture experiment].

The microbial reduction of ferrihydrite, lepidocrocite, hematite, goethite and aluminum-substituted iron oxides were examined by iron-reducer GS-15 under anaerobic pure culture condition. The results indicated that the ferrihydrite and lepidocrocite can be rapidly reduced by iron-reducer, and the percentage of microbial reduction are respectively 95.4% and 95.8% after 4 days incubation at 25 degrees C. The other iron oxides like hematite, Al-hematite, goethite and Al-goethite are very difficult to reduce during short-term incubation. The amounts of Fe(III)-reducing, Fe(II)-producing and Fe-reducing calculated by acetate consumption are identical under the conditions of lower concentration iron oxides addition.

Culture Media↗
PubMedDate not supplied

[Biological oxidation of sulfide raw material using a culture of Thiobacillus ferrooxidans under various conditions of leaching].

Major parameters of the first stage of leaching of a copper-zinc sulfide product by a culture of Thiobacillus ferrooxidans have been studied, including the effects of solid phase concentration, Fe2+ and Fe3+ ions, pH, and the intensity of mixing. The first stage of leaching of the sulfide raw material is optimum under the following conditions: pH of the original leaching solution equal to 1.6; Fe3+ concentration of order of 10 g/l; and vigorous mixing of the suspension at solid phase concentrations of 30-35%. A theoretical substantiation of the observed dependences is proposed.

Biodegradation, Environmental↗
PubMedDate not supplied

[Pathophysiological mechanisms of formation of iron deficiency states and modern approaches to administration of oral forms of iron preparations in their prophylaxis and treatment].

In the review, modern conceptions are presented on mechanisms of formation of iron deficiency states and status of the problem of administration of pathogenetically validated treatment in iron deficiency anemia (IDA) is analyzed. A brief comparative analysis is given of iron-containing medicines used in Ukraine. Current principles of medical management of IDA are set forth. Under adequate treatment with making use of modern iron-containing medicinal agents one can achieve a positive clinical effect. Data are submitted on high efficacies and good tolerability of the hydroxidepolymaltose-based iron preparations to be employed in IDA.

Administration, Oral↗
PubMedDate not supplied

[Physiology of organotrophic and lithotrophic growth of the thermophilic iron-reducing bacteria Thermoterrabacterium ferrireducens and Thermoanaerobacter siderophilus].

Growth physiology of the iron-reducing bacteria Thermoterrabacterium ferrireducens and Thermoanaerobacter siderophilus was investigated. The stimulation of the organotrophic growth of T. ferrireducens and T. siderophilus in the presence of Fe(III) was shown to be due to the utilization of ferric iron as an electron acceptor in catabolic processes and not to the effect exerted on the metabolism by Fe(II) or by changes in the redox potential. It was established that Fe(III) reduction in T. ferrireducens is not a detoxication strategy. In T. siderophilus, this process is carried out to relieve the inihibitory effect of hydrogen. T. ferrireducens was shown to be capable of lithoautotrophic growth with molecular hydrogen as electron donor and amorphous ferric oxide as electron acceptor, in the absence of any organic substances. The minimum threshold of H2 consumption was 3 x 10(-5) vol % of H2. The presence of CO dehydrogenase activity in T. ferrireducens suggests that CO2 fixation in this organism involves the anaerobic acetyl-CoA pathway. T. siderophilus failed to grow under lithoautotrophic conditions. The fact that T. ferrireducens contains c-type cytochromes and T. sidrophilus lacks them confirms the operation of different mechanisms of ferric iron reduction in these species.

Bacteria, Anaerobic↗
PubMed2002

[Determination of major and minor components in standard talc samples by ICP-AES].

The standard talc sample was fused with Na2CO3 and Na2B4O7 and then the fused disc was dissolved with HCl solution. SiO2, MgO, Al2O3, Fe3O2 and CaO in talc samples were determined simultaneously by ICP-AES. The optimum analytical line with high sensitivity and low spectral interference were carefully chosen. The sources and properties of the interference were discussed. The recoveries for these elements were 98.8%-104.4%, with precision of 0.12%-2.4% RSD (n = 6). The results of major and minor components in talc samples by this method were in agreement with those provided by the standard method.

Aluminum Oxide↗
PubMed2004

Enhanced remediation of carbon tetrachloride by Fe(II)-Fe(III) systems in the presence of copper ions.

The effect of Cu(II) ion on the dechlorination of carbon tetrachloride (CT) by Fe(II) associated with various iron oxides was investigated. Iron oxides including goethite, hematite, ferrihydrite and magnetite were selected as the model compounds. CT was dechlorinated to chloroform (CF) by 3 mM Fe(II) in iron oxide suspensions at pH 7.2. The dechlorination followed pseudo first-order kinetics and the pseudo first-order rate constants (k(obs)) were 0.048 h(-1), 0.0836 h(-1), 0.0609 h(-1) and 0.0144 h(-1) in goethite-, hematite-, ferrihydrite- and magnetite-amended systems, respectively. Addition of Cu(II) into systems increased the k(obs) for CT dechlorination significantly. A 3- to 120-fold increase in k(obs) relative to the systems without Cu(II) was observed when 0.5 mM Cu(II) was added to the Fe(II)-Fe(III) suspensions. The pH of the system is an important factor controlling the dechlorination rate of CT. The increase in concentrations of Fe(II) and iron oxides also enhanced the dechlorination efficiency and rate of CT. Moreover, a linear relationship between the k(obs) and Cu(II) concentration ranging between 0 and 0.4 mM was observed. Results obtained demonstrate the feasibility of using surface-bound iron species with Cu(III) for the detoxification of chlorinated solvents in the contaminated aquifers.

Carbon Tetrachloride↗
PubMed2005

Factors causing PAC cake fouling in PAC-MF (powdered activated carbon-microfiltration) water treatment systems.

Two pilot-scale powdered activated carbon-microfiltration (PAC-MF) reactors were operated using river water pretreated by a biofilter. A high permeate flux (4 m/d) was maintained in two reactors with different particle sizes of PAC. High concentration (20 g/L) in the PAC adsorption zone demonstrated 60-80% of organic removal rates. Analysis on the PAC cake fouling demonstrated that attached metal ions play more important role than organic matter attached on PAC to the increase of PAC cake resistance. Effects of factors which may cause PAC cake fouling in PAC-MF process were investigated and evaluated by batch experiments, further revealing that small particulates and metal ions in raw water impose prominent influence on the PAC cake layer formation. Fe (II) precipitates after being oxidized to Fe (III) during PAC adsorption and thus Fe(ll) colloids display more significant effect than other metal ions. At a high flux, PAC cake layer demonstrated a higher resistance with larger PAC due to association among colloids, metals and PAC particles, and easy migration of small particles in raw water into the void space in the PAC cake layer. Larger PAC possesses much more non-uniform particle size distribution and larger void space, making it easier for small colloids to migrate into the voids and for metal ions to associate with PAC particles by bridge effect, hence speeding up and intensifying the of PAC cake fouling on membrane surface.

Adsorption↗
PubMed2005

[Treatment of iron deficiency anaemia in pregnant, puerperal and gynaecological patients--different drugs, different approaches].

UNLABELLED: According to WHO about 50 per cent of women of fertile age have iron deficiency anaemia (IDA). Iron loss > 80 mg per month, with menstruation in 22 per cent of women cause a negative iron balance in the course of time. About 40 per cent of women have data of prelatent iron deficiency still before conception, and if the demands of occured pregnancy are added, IDA is quickly reached. Over 30 per cent of puerperal women are affected by anaemia. PURPOSE: To make a pharmacoeconomic assessment of peroral antianaemic drugs used for treatment of IDA in pregnant, puerperal and gynaecologically ill women. MATERIALS: There are presented- daily intake of drugs, number of drug package taken, the price of a drug package, value of treatment a month, reimbursement of the drugs below: Ferro Gradumet, Maltofer Fol, Sorbifer Durules, Tot'hema, Legofer, Ferro-Folgamma, Tardiferon. RESULTS: The survey made and the data of own studies show that the most important in treatment of IDA are the choice of iron- containing drug and the correct therapeutic approach. The choice of peroral iron- containing therapy is determined by: high "patient compliance"--good tolerance, independence on food intake, once daily intake, low frequency of adverse effects and treatment with low price (economic effect). CONCLUSION: The most suitable for treatment of IDA in pregnant and puerperal women are Maltofer Fol and Sorbifer Durules. Maltofer Fol is with the best correlation price: "patient compliance". Tot'hema and Legofer have a good tolerance, a few adverse effects, but they are with high price. Ferro folgamma has not a high "patient compliance" and it has comparatively high price. Ferro gradumet has a low price and low "patient compliance".

Anemia, Iron-Deficiency↗
PubMed1991

[Biological attestation of the fibrogenic effect of dust from selected coal mines on the lung tissue].

The studies aimed at determining the changes in respiratory system of animals after intratracheal administration of settled dusts sampled from seams 116 and 188 in Janina colliery and seams 314 and 317 in Victoria colliery. For comparison, dusts sampled gravimetrically from a/m seams in Janina and Victoria collieries were intratracheally administered to animals. Crystalline silica concentrations determined by Polezajew method in dusts from Janina and Victoria collieries were 2.4% to 8.1% and 1.6% to 2.8%, respectively. Biological aggressiveness of mine dusts was examined using intraperitoneal, pulmonary and hemolytic tests. Hydroxyproline concentration was determined by Stegemann method using the modification of Hurych and Chvapil (2). The results of biochemical analysis were subjected to a statistical analysis by t-Student's test. Specimens from lungs for histopathological examination were stained with hematoxylin and eosin, while collagen fibres were stained by Van Gieson method. A single intratracheal administration of dust collected gravimetrically from 116 seam and settled dust from seam 118 in Janina colciery caused, after six months, a hypro-increase by more than three times comparing with the control group. No correlations were found between higher hypro-levels in lungs and histological changes. It seems probable that higher hypro-levels in lungs can be caused mainly by SiO2 whose concentration in dusts was 8%. Similar concentrations of aluminium and ferrous compounds may suggest that their influence on the biological activity of silica is mutually eliminated. After a six-month intratracheal administration of dusts from Victoria colliery in Wałbrzych, a hypro-decrease was observed compared to a three-month period of administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗
PubMed2006

[Comparison of hydroxyl radical production rates in H2O2 solution under homogeneous catalysis of Fe3+ or Fe2+].

The production of *OH radicals was investigated by using the electron spin resonance (ESR) method with 5,5-dimethyl-1-lpyrroline-1-oxide (DMPO) as spin trap reagent. ESR signals composed of 4 lines with a 1:2:2:1 intensity ratio indicated the formation of *OH radicals in the Fenton-like reaction. For both systems, the production rates of hydroxyl radicals in the initial stage were considerably high, and increased with increasing concentrations of H2O2 and Fe2+ or Fe3+. However, the radical production rate in Fenton reaction system was markedly higher than that in Fenton-like reaction under similar dosing conditions. The differences of radical production rates between the reaction systems remained even in the slow reaction stage. The optimum pH ranges of the production of *OH radicals in Fenton process and Fenton-like process were 2.5 to approximately 3.5 and 2.8 to approximately 3.0 respectively. The above results demonstrate that the Fenton system and Fenton-like system are possibly based on different reaction mechanisms.

Catalysis↗
PubMedDate not supplied

Oral iron.

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Anemia, Iron-Deficiency↗
PubMed2006

Advanced oxidation processes in azo dye wastewater treatment.

The chemical degradation of synthetic azo dyes color index (C.I.) Acid Orange 7, C.I. Direct Orange 39, and C.I. Mordant Yellow 10 has been studied by the following advanced oxidation processes: Fenton, Fenton-like, ozonation, peroxone without or with addition of solid particles, zeolites HY, and NH4ZSM5. Spectrophotometric (UV/visible light spectrum) and total organic carbon measurements were used for determination of process efficiency and reaction kinetics. The degradation rates are evaluated by determining their rate constants. The different hydroxyl radical generation processes were comparatively studied, and the most efficient experimental conditions for the degradation of organic azo dyes solutions were determined.

Azo Compounds↗
PubMed1991

Effects of Fe2+, Fe3+ and desferrioxamine on paraquat accumulation by rabbit kidney cortex slices.

Effects of Fe2+, Fe3+ and desferrioxamine (DFO) on the accumulation of paraquat (PQ) into rabbit kidney cortical slices were studied. Fe3+ showed dose-dependent inhibition of PQ accumulation. Fe2+ had a more powerful stimulatory effect on the lipid peroxidation of cortical slices than Fe3+, but it did not reduce PQ accumulation. The addition of DFO made the inhibitory effect of Fe3+ on PQ accumulation more pronounced. These results suggest that Fe3+ is able to inhibit the accumulation of PQ independent of its peroxidative action, and that Fe(3+)-desferrioxamine (ferrioxamine) may serve as an antidote for the toxicity of PQ.

Animals↗
PubMed1991

Reactions of lignin peroxidase compounds I and II with veratryl alcohol. Transient-state kinetic characterization.

Stopped-flow techniques were utilized to investigate the kinetics of the reaction of lignin peroxidase compounds I and II (LiPI and LiPII) with veratryl alcohol (VA). All rate data were collected from single turnover experiments under pseudo first-order conditions. The reaction of LiPI with VA strictly obeys second-order kinetics over the pH range 2.72-5.25 as demonstrated by linear plots of the pseudo first-order rate constants versus concentrations of VA. The second-order rate constants are strongly dependent on pH and range from 2.62 x 10(6) M-1 s-1 (pH 2.72) to 1.45 x 10(4) M-1 s-1 (pH 5.25). The reaction of LiPII and VA exhibits saturation behavior when the observed pseudo first-order rate constants are plotted against VA concentrations. The saturation phenomenon is quantitatively explained by the formation of a 1:1 LiPII-substrate complex. Results of kinetic and rapid scan spectral analyses exclude the formation of a LiPII-VA cation radical complex. The first-order dissociation rate constant and the equilibrium dissociation constant for the LiPII reaction are also pH dependent. Binding of VA to LiPII is controlled by a heme-linked ionizable group of pKa approximately 4.2. The pH profiles of the second-order rate constants for the LiPI reaction and of the first-order dissociation constants for the LiPII reaction both demonstrate two pKa values at approximately 3.0 and approximately 4.2. Protonated oxidized enzyme intermediates are most active, suggesting that only electron transfer, not proton uptake from the reducing substrate, occurs at the enzyme active site. These results are consistent with the one-electron oxidation of VA to an aryl cation radical by LiPI and LiPII.

Basidiomycota↗