Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ferric Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1982

Chemical aspects on chromate in cement.

A certain amount of chromate can be added to calcium aluminate and calcium aluminate ferrite, 2 compounds present in clinker, without being extractable with water. Solutions of sulfate and the chemically related selenate and molybdate can extract about 2/3 of the added chromate. Also a certain amount of molybdate can be added to calcium aluminate without being extractable with water. About 2/3 of the added molybdate can be extracted with solutions of sulfate, selenate and chromate. Chromate present in clinker can partly be extracted with solutions of sulfate, selenate and molybdate. The present results indicate that chromate is partly present in crystals of calcium aluminate and calcium aluminate ferrite and that the correlation between chromate and sulfate in cement is due to an equilibrium between these two compounds inside and outside the crystals. The results also indicate that chromate, sulfate, selenate and molybdate can substitute each other. As cement always contains gypsum, which is partly water soluble, the possibility to make chromatefree cement is limited.

Aluminum↗
PubMed2003

Photochemical oxidation of As(III) in ferrioxalate solutions.

Photochemical reactions involving aqueous Fe(III) complexes are known to generate free radical species such as OH* that are capable of oxidizing numerous inorganic and organic compounds. Recent work has shown that As(III) can be oxidized to As(V) via photochemical reactions in ferric-citrate solutions; however, the mechanisms of As(III) oxidation and the potential importance of photochemical oxidation in natural waters are poorly understood. Consequently, the objectives of this study were to evaluate oxidation rates of As(III) in irradiated ferrioxalate solutions as a function of pH, identify mechanisms of photochemical As(III) oxidation, and evaluate the oxidation of As(III) in a representative natural water containing dissolved organic C (DOC). The oxidation of As(III) was studied in irradiated ferrioxalate solutions as a function of pH (3-7), As(III), Fe(III), and 2-propanol concentration. Rates of As(III) oxidation (0.5-254 microM h(-1)) were first-order in As(III) and Fe(III) concentration and increased with decreasing pH. Experiments conducted at pH 5.0 using 2-propanol as an OH* scavenger in light and dark reactions suggested that OH* is the important free radical responsible for As(III) oxidation. Significant rates of As(III) oxidation (4-6 microM h(-1)) were also observed in a natural water sample containing DOC, indicating that photochemical oxidation of As(III) may contribute to arsenic (As) cycling in natural waters.

Arsenic↗
PubMed2005

Sorption of the antimicrobial ciprofloxacin to aluminum and iron hydrous oxides.

Solution chemistry (pH, ionic strength (I), and sorbate-to-sorbent ratio) effects on ciprofloxacin sorption to hydrous oxides of Al (HAO) and Fe (HFO) were investigated using macroscopic and spectroscopic analyses. Sorption to both HAO and HFO showed a strong pH-dependent behavior, following the fraction of zwitterionic species over the entire pH range studied. Increase in I from 0.01 to 0.5 M had an insignificant effect on the extent of ciprofloxacin sorption, and isotherms were well-described by the Langmuir model. HFO possessed a higher sorption capacity (0.066 mmol kg(-1)) than HAO (0.041 mmol kg(-1)). Ligand-promoted dissolution of hydrous oxides, more pronounced for HAO, was observed in the presence of ciprofloxacin, but at a fairly high initial concentration (0.5 mM). Attenuated total reflectance Fourier transform infrared spectroscopy analysis indicated that different types of ciprofloxacin surface complexes are formed with HAO and HFO; while a monodentate mononuclear complex (with -COO-) appears likely between ciprofloxacin and HAO, keto O and one O from COO- seem to be involved in the formation of a six-membered ring with Fe on the HFO surface. The study results are expected to increase our understanding of the environmental reactivity of fluoroquinolones, an important class of antimicrobial compounds.

Adsorption↗
PubMed1995

Use of Mishell-Dutton culture for the detection of the immunosuppressive effect of iron-containing compounds.

Mishell-Dutton culture, known as an in vitro model for the evaluation of the humoral immune response of mice spleen cells to sheep red blood cells (SRBC), was used to study the immunosuppressive effect of iron-containing compounds. This response was indicated by the number of antibody forming cell (AFC) per million nucleated cells. Ferrous sulfate and ferric citrate (0.1 mM), when continuously present in Mishell-Dutton culture, significantly decreased the SRBC AFC response by approximately 63% and 86% of the control values, respectively. Ferric citrate, preincubated (24 h) with spleen cells and followed by lavage, significantly decreased the SRBC AFC response by approximately 54% of the control values. Primary and iron-treated coal, in concentrations ranging from 40 micrograms.ml-1 to 120 micrograms.ml-1, significantly decreased the SRBC AFC response when continuously present in Mishell-Dutton culture. Iron-treated coal, suppressed this response, in dose-dependent amounts, to a greater extent than did the primary coal:73% versus 54% at 120 micrograms.ml-1. We concluded that Mishell-Dutton culture is suitable for studying the immunotoxicity of iron and these results may contribute to explain a decrease of host resistance against parasitic and bacterial infection in workers exposed to iron.

Animals↗
PubMed1996

Alveolar macrophages accumulate iron and ferritin after in vivo exposure to iron or tungsten dusts.

Extracellular iron present in alveolar structures may contribute to oxidative lung injury induced by toxic mineral dusts by enhancing dust-induced generation of hydroxyl radicals. Alveolar macrophages (AMs) can sequester iron within ferritin and limit generation of hydroxyl radicals. In the current study we sought to assess whether AMs accumulate iron and ferritin after in vivo exposure to a dust with high iron content, to iron oxide, or to an inflammatory dust, calcium tungstate. We performed lung lavage 1, 7, 14, 28, 42, and 56 days after intratracheal instillation of mineral dust in saline solution or instillation of saline solution alone and quantitated cell recovery and AM content of iron and ferritin. Instillation of iron oxide increased neutrophil recovery only on a day 1 when compared with results in controls, whereas calcium tungstate increased neutrophil recovery through day 14. AMs recovered after instillation of iron oxide contained increased amounts of iron and ferritin, beginning on day 1 and progressing through day 56 after treatment (7.57 +/- 0.38 microgram iron per 10(6) AMs vs 1.54 +/- 0.28 microgram iron per 10(6) AMs for controls, p < 0.001; and 5908 +/- 768 ng ferritin per 10(6) AMs vs 395 +/- 20 ng ferritin per 10(6) AMs, p < 0.001). AMs recovered after calcium tungstate instillation also contained increased amounts of iron and ferritin beginning 14 days after treatment, with greatest content 42 days after treatment (4.85 +/- 0.68 microgram iron per 10(6) AMs, p < 0.001, and 2274 +/- 736 ng ferritin per 10(6) AMs, p < 0.001). Tumor necrosis factor, which can enhance iron accumulation by macrophages, was spontaneously released by AMs recovered from tungsten-treated rats. These studies indicate that AMs accumulate iron and ferritin in response to both iron loading of the lungs with iron oxide exposure and lung inflammation induced by calcium tungstate exposure.

Adult↗
PubMed2003

Removal of PCR inhibitors from soil DNA by chemical flocculation.

Extracting high-purity DNA directly from soil has become essential for the study of microorganisms in environmental samples. However, many soils contain compounds that inhibit enzymes involved in manipulating DNA. In this study, chemical flocculation using multivalent cations was investigated as a potential method for eliminating soil-based inhibitors during the extraction process. The addition of AlNH(4)(SO(4))(2) during extraction significantly reduced the co-purification of PCR inhibitors with minimal loss of DNA yield.

Alum Compounds↗
PubMed2002

Microsomal P450-catalyzed N-dealkylation of N,N-dialkylanilines: evidence for a C(alpha)-H abstraction mechanism.

The early proposal that P450-catalyzed N-dealkylation of N,N-dialkylamines proceeds through a single-electron-transfer (SET) mechanism was later challenged in favor of the C(alpha)-H abstraction mechanism. In the present study, a series of N-alkyl-N-cyclopropyl-p-chloroaniline probes have been used to examine whether the P450-catalyzed N-dealkylations proceed through a C(alpha)-H abstraction and/or a SET mechanism, using phenobarbital-induced rat liver microsomal P450 enzymes as a model system. While the findings are highly consistent with a C(alpha)-H abstraction mechanism, further experimental evidence may be necessary to completely rule out the SET mechanism.

Alkylation↗
PubMed2001

New contrast agents for imaging the liver.

The contrast agents suited for hepatic imaging can be divided into nonspecific, extracellular space- (ECS) directed, reticuloendothelial system- (RES) selective, and hepatocyte-selective compounds. There is a wide variation in regard to biodistribution, pharmacokinetics, contrast behavior, and tissue specificity. The ECS contrast agents provide information on vascularization and perfusion similar to that of X-ray contrast agents. The RES- and hepatocyte-specific contrast agents offer more "functional" information that may enhance tissue characterization; however, the biology of the different hepatocellular and nonhepatocellular tumors is limiting the diagnostic efficacy of the tissue-specific compounds in many respects.

Animals↗
PubMed2005

Chemical and physical surface and bulk material characterization of white ProRoot MTA and two Portland cements.

OBJECTIVES: The chemical and physical properties of white ProRoot MTA were analyzed in the bulk and at the surface and compared with two common Portland cements types CEM1 and CEM2. METHODS: The main components were analyzed by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray analysis (EDX), and the minor constituents were identified with inductively coupled plasma optical emission spectroscopy (ICP-OES). Moreover, the setting of the different cements was studied: the chemical composition of the surface of both powder and bound cement was investigated by XPS and the morphological changes were examined by scanning electron microscopy (SEM). RESULTS: In ProRoot MTA, the amount of gypsum is approximately half of that of the Portland cements. ProRoot MTA consists of less toxic heavy metals (Cu, Mn, Sr), less chromophores (Fe3+), and less Al-species, but contains about 2 at % Bi. In contrast to Portland cements, ProRoot MTA contains about 2 at.% Bi. In all three products, the amount of sulfur at the surface in the bound cements was 3 times higher than in the powder, indicating that in terms of the kinetics of the hardening reaction, a sulfate action mechanism prolongs the setting time. The Portland cements are composed of particles with a wide range of size, whereas ProRoot MTA showed a uniform and smaller particle size. SIGNIFICANCE: With regard to chemical and physical surface and bulk properties, ProRoot MTA cannot simply be substituted by the cheaper Portland cement. Both products are similar but not equal and exhibit marked differences.

Aluminum Compounds↗
PubMed1999

Current methods of finish-line exposure by practicing prosthodontists.

PURPOSE: The purpose of this study was to survey members of The American College of Prosthodontists to evaluate current methods of finish-line exposure. In addition, frequency of use of epinephrine compounds and observed side effects were assessed. MATERIALS AND METHODS: A questionnaire was mailed to the 2,436 members of The American College of Prosthodontists. Group differences were evaluated using chi 2 analysis. RESULTS: Completed questionnaires were returned by 1,246 prosthodontists, which is a return rate of 51%. Ninety-eight percent of respondent prosthodontists use retraction cord, and 48% use a double-cord technique. Plain cord is the most commonly used cord (44%), followed by aluminum chloride-impregnated cord (18%), and epinephrine-impregnated cord (14%). Nine hundred one respondents (81%) soak the cord before placing it in the gingival sulcus. The most common medicament for soaking the cords is buffered aluminum chloride (55%). Side effects to epinephrine were reported by 387 respondents (33%), with the most common side effect reported being increased pulse rate, followed by anxiety. Approximately one quarter (24%) of the prosthodontists surveyed had observed side effects to chemical agents other than epinephrine. CONCLUSIONS: Prosthodontists throughout the country use many different techniques and agents to expose finish lines. No statistically significant differences (p > .05) were found between year of specialty training completion groups with respect to retraction cord use. Copper bands are used significantly more frequently (p < .05) in the northwest region of the United States than elsewhere.

Aluminum Chloride↗
PubMed2004

Behaviour of endocrine disrupting chemicals during the treatment of municipal sewage sludge.

Agricultural application of municipal sewage sludge has been emotionally discussed in the last decades, because the latter contains endocrine disrupting chemicals (EDCs) and other organic micropollutants with unknown fate and risk potential. Bisphenol A (BPA) was chosen as a model substance to investigate the influence of sludge conditioning on the end-concentration of EDCs in sludge. Adsorption studies with radioactive-labelled BPA showed that more than 75% BPA in anaerobically digested sludge is bound to solids (log Kd = 2.09-2.30; log Koc = 2.72-3.11). Sludge conditioning with polymer or iron (III) chloride alone had no influence on the adsorption of BPA. After conditioning with iron (III) chloride and calcium hydroxide desorption of BPA took place. Apparently, it occurred due to the deprotonation of BPA (pKa= 10.3) as the pH-value reached 12.4 during the process. The same behaviour is expected for other phenolic EDCs with similar pKa (nonylphenol, 17beta-estradiol, estron, estriol, 17alpha-ethinylestradiol). This study shows high affinity of BPA to the anaerobically digested sludge and importance of conditioning in the elimination of EDCs during the sludge treatment. Addition of polymer is favourable in the case of sludge incineration. Conditioning with iron (III) chloride and calcium hydroxide shows advantages for the use of sludge as fertiliser.

Absorption↗
PubMed1990

[Durability of bonding between 4-META/MMA-TBB resin to dentin pretreated with 10-3. The effect of 10-3 pretreating period and subsequent glutaraldehyde treatment].

Adhesion durability between dentin pretreated with 10-3 and 4-META/MMA-TBB resin was studied. Reduction of etching periods with 10-3 was not so effective as expected. The weakening of bond strength during immersion in water at 37 degrees C to the dentin pretreated for 1 sec occurred faster than those for either 5 sec or 10 sec. The strength decreased from 12 MPa at 1 day to 9 MPa at 3 months, 3 MPa at 6 months and finally 2 MPa at 1 year in the case of 1 sec pretreated dentin. On the other hand, the strength became half after the storage in water for 1 year in the cases of 5 and 10 sec pretreated dentins. Combination of 10-3 pretreatment and subsequent glutaraldehyde treatment could stabilize the decrease but not completely. SEM and TEM examinations suggested that dentinal collagen exposed by the etching but not entangled and impregnated by poly (4-META-co-MMA) easily deteriorated by water during the longer immersion. Collagen modified with 10-3 and then with glutaraldehyde was also changed by the longer immersion.

Acid Etching, Dental↗
PubMed1970

Spin-state changes in cytochrome P-450cam on binding of specific substrates.

The electron paramagnetic resonance signals of the soluble P-450 cytochrome from Pseudomonas putida were observed at temperatures from 4.2 to 80 degrees K. As isolated, P-450 has a signal typical of a low spin ferric-heme compound with sulfur as one of the axial ligands (g = 2.45, 2.26, 1.91(5)). We also detected a minor signal typical of high spin ferric heme (g = 8, 4, 1.8) equivalent to less than 7% of the heme at temperatures below 20 degrees K. On titration with the substrate, (+)-camphor, the low spin signal decreased and the high spin signal increased, maximally representing about 60% of the heme. For reasons not thus far understood, 40% of the heme is not converted to high spin by either (+) or (-)-camphor. The high spin signal has a rhombic character which is stronger than any previously observed with a heme compound (E = 0.33 cm(-1); D = 3.8 cm(-1); E/D = 0.087). We conclude that P-450(cam) as isolated is equal to or more than 95% in a low spin form probably having sulfur as one of the axial ligands. The binding of substrate displaces this ligand sufficiently to allow for conversion from a low to a high spin form.

Cold Temperature↗
PubMed1986

Hydroperoxyfatty acids inactivate the reticulocyte lipoxygenase independently of a hydroperoxidase reaction.

From a comparison of 9Ds-HPODE and 13Ls-HPODE and their methyl esters as substrates and inactivating agents of reticulocyte lipoxygenase it is concluded that the compounds inactivate the enzyme independently of any hydroperoxidase reaction. The protective effect of 4-nitrocatechol indicates the formation of Fe(III) complexes of the enzyme with the hydroperoxyfatty acid compounds prior to inactivation.

Anaerobiosis↗
PubMed1981

Neurotoxicity of quelamycin in the rat.

Male Sprague-Dawley rats were given a single dose of 10 or 20 mg/kg quelamycin intravenously and perfusion fixed at 4, 12, 28 and 48 days after drug administration. Light microscopical study of 1 micrometer thick sections of dorsal root ganglia revealed focal regions of neuronal nuclear clearing involving 40-50% of neurons at 4 days. There was subsequent progressive reduction in the incidence of such lesions. Neuronal necrosis apparently affecting less than one percent of dorsal root ganglia neurons was noted initially at 12 days in the 20 mg/kg group and 28 days in the 10 mg/kg group. Comparison of these findings with previous studies indicated that quelamycin was less neurotoxic to rats than its parent compound adriamycin.

Animals↗