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PubMed2004

Determination of a polymeric hindered amine light stabilizer in polypropylene formulated with magnesium hydroxide flame retardant by reactive thermal desorption-gas chromatography.

A polymeric hindered amine light stabilizer (HALS), Tinuvin 622 (MW [symbol: see text] 4000), in PP materials formulated with a magnesium hydroxide flame retardant was determined by reactive thermal desorption (RTD) gas chromatography (GC). Two kinds of the HALS components that were formed through the RTD in the presence of tetramethylammonium hydroxide [(CH3)4NOH, TMAH] were clearly observed in the chromatograms of the PP samples, with negligible interference from the other additives and the PP substrate. Here, the coexisting flame retardant was proved to affect significantly the RTD process of the occluded HALS. As a result, the recovery of the HALS components in the RTD-GC chromatograms of the PP samples increased with increase in the content of the flame retardant. This enhancement of the HALS recovery is attributed mainly to the preferential exposure of the HALS on the surface of the ground PP sample through the interaction between the polymeric HALS and the flame retardant in the molten PP during kneading. In spite of such a considerable action of the flame retardant, the observed intensities of the characteristic peaks of HALS by RTD-GC showed a good linear relationship with the HALS content in the PP samples with constant content of the flame retardant (50 phr); this relationship could be used as the calibration line for the determination of the polymeric HALS in the PP materials containing the flame retardant.

Journal Article↗
PubMed2006

Determination of soluble bromine in an extra-high-pressure mercury discharge lamp by sodium hydroxide decomposition-suppressed ion chromatography.

We have established a simple method for assaying the quantity of soluble bromine in the discharge tubes of an extra-high-pressure mercury discharge lamp. Each discharge tube is destroyed in 5 ml of 10 mM sodium hydroxide, and the recovered sodium hydroxide solution is analyzed by suppressed-ion chromatography using gradient elution. We have clarified that this method can assay less than 1 microg of soluble bromine in a discharge tube.

Journal Article↗
PubMed2006

Gold ultra-microelectrode arrays: application to the steady-state voltammetry of hydroxide ion in aqueous solution.

Gold ultra-microelectrode arrays are used to explore the electrochemical oxidation of hydroxide ions and are shown to be analytical useful. Two types of ultra-microelectrode arrays are used; the first consist of 256 individual electrodes of 5 microm in radius, 170 of which are electrochemically active in a cubic arrangement which are separated from their nearest neighbour by a distance of 100 microm. The second array compromises 2597 electrodes of 2.5 microm in radius and of which 1550 of which are electrochemically active in a hexagonal arrangement separated by the nearest neighbour by 55 microm. Well defined voltammetric waves are found with peak currents proportional to the concentration of hydroxide ions in the range 50 microM to 1 mM. Detection limits of 20 microM using the 170 ultra-microelectrode and 10 microM with the 1550 ultra-microelectrode array are shown to be possible but with a higher sensitivity of 4 mA M(-1) observed using the 1550 ultra-microelectrode array compared to 1.2 mA M(-1) with the 170 ultra-microelectrode array.

Journal Article↗
PubMedDate not supplied

Evaluation of barium hydroxide treatment efficacy on a dolomitic marble.

The Arch of Peace, by Luigi Cagnola, is one of the most famous neoclassical monuments in Milan. It has been subjected to conservative intervention in 1998. In the present paper the efficacy of the consolidation by means of barium hydroxide has been evaluated. The stone material showed severe degradation phenomena as: erosion, pulverisation, exfoliation. The analytical data acquired through X-ray diffraction (XRD), infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM-EDX), allowed to compare the conditions of stone before and after the treatment with barium hydroxide. The presence of barium has been put in evidence mainly on the surface as barium sulphate, whereas barium is only sporadically present within the thickness of the decayed material. The treatment was judged not satisfying and its inefficacy is, most probably, due to a not suitable cleaning procedure carried out before the consolidation.

Barium Compounds↗
PubMed1975

The action of quartz in the presence of iron hydroxides in the human lung.

In 1932 Kettle reported that the fibrogenic action of quartz particles is inhibited when they are coated with iron. Many authors subsequently confirmed this finding. Reif et al., who studied the effect of different iron-ore mine dusts, showed that, like aluminium hydroxide, iron hydroxide has a strong effect in inhibiting the fibrogenic action due to quartz. The findings of this paper, based on an X-ray survey of a group of 7735 iron ore miners, on autopsy examinations, tissue dust analysis and physiological examinations, confirm the view that FeO(OH) is a most powerful inhibiting substance.

Adult↗
PubMed1975

Studies on the dominant-lethal and fertility effects of the heavy metal compounds methylmercuric hydroxide, mercuric chloride, and cadmium chloride in male and female mice.

Dominant-lethal effects of 10 mg/kg methylmercuric hydroxide were studied in male mice from two hybrid stocks and in females from one of these stocks. Two other compounds, mercuric chloride (2 mg/kg) and cadmium chloride (2 mg/kh), were studied only in females for dominant-lethal (in one hybrid stock) and reproductive capacity effects (in two hybrid and one mixed stocks). All compounds were administered in a single intraperitoneal injection. When males of one of the two stocks studied were treated with methylmercuric hydroxide, the females to which they were mated exhibited a slight reduction in the total number of implantations and in the number of living embryos. These reductions were accompanied by a very small increase in the incidence of dead implantations. In females, cadmium chloride had no detectable dominant-lethal or other fertility effects, except superovulation. On the other hand, the two mercury compounds slightly reduced the numbers of implants and living embryos in females subjected to dominant-lethal studies. The two mercury compounds also induced a slight reduction in that long-term reproductive performance of one stock of females. These results and those reported earlier by others, indicate that the mercury compounds studied so far are not potent inducers of dominant-lethal mutations in male and female mice. It is not clear whether the small effects on male or female fertility induced in some cases, particularly the increase in dead implantations and reductions in the number of living embryos, were attributable to dominant-lethal mutations or to nongenetic causes.

Animals↗
PubMedDate not supplied

[Effect of iron hydroxide on the phosphate elimination during anaerobic digestion of active sludge].

Addition of iron (III) hydroxide during methanogenic digestion of active sludge by anaerobic sludge displaying an iron-reducing activity resulted in a microbial reduction of iron (III) with formation of iron (II), capable of precipitating phosphates. Feasibility of eliminating 66.6 to 99.6% of dissolved phosphate at initial concentrations of 1000 to 3500 mg PO4(3-)/l by adding 6420 mg/l iron (III) hydroxide into a reactor for anaerobic fermentation of active sludge. The optimal ratio of iron (III) added to dissolved phosphate eliminated (mg) providing a 95% elimination amounted to 2:1. These results may be used in a new technology for anaerobic wastewater treatment with phosphate elimination.

Bacteria, Anaerobic↗
PubMed1987

Pharmacokinetics of iron salts and ferric hydroxide-carbohydrate complexes.

Pharmacokinetic measurements of ferrous sulphate and ferric hydroxide-polymaltose complex on anaemic and non-anaemic rats have shown different postabsorption serum iron levels, invasion and elimination constants and distribution volumes for the two preparations. But nevertheless the absorption and utilization ratios of iron from both preparations are equal. It is therefore not justified to calculate utilization ratios for chemically different iron preparations on the basis of postabsorption serum iron measurements. Similar pharmacokinetic differences of these two iron preparations could also be found in clinical trials, which means that different serum iron increase results in an equal utilization ratio for both preparations. It is clear that ferrous sulphate and ferric hydroxide-polymaltose complex must have a different absorption mechanism. The postulated absorption mechanism is in agreement with all the facts known today and does explain the pharmacokinetic difference between the investigated preparations.

Anemia↗
PubMed1987

Synovectomy of the rheumatoid knee using intra-articular injection of dysprosium-165-ferric hydroxide macroaggregates.

One hundred and eleven patients who had seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with intra-articular injection of 270 millicuries of dysprosium-165 bound to ferric hydroxide macroaggregates. A two-year follow-up was available for fifty-nine of the treated knees. Thirty-nine had a good result; nine, a fair result; and eleven, a poor result. Of the twenty-five knees that had Stage-I radiographic changes, nineteen had a good result. Of the thirty-four knees that had Stage-II radiographic changes, twenty showed a good result. Systemic spread of the radioactivity from the injected joint was minimum. The mean whole-body dose was calculated to be 0.3 rad and that to the liver twenty-four hours after injection, 3.2 rads. The results indicated that dysprosium-165-ferric hydroxide macroaggregate is an effective agent for performing radiation synovectomy, particularly in knees that have Stage-I radiographic changes. Because of the minimum rate of systemic spread of the dysprosium-165, it offers a definite advantage over agents that previously have been used.

Adult↗
PubMed1993

Denaturing HPLC purification of tritylated oligonucleotides using tetraethylammonium hydroxide.

Purification of oligonucleotides by HPLC is limited by association between failure sequences and full-length oligonucleotide. We describe a protocol for denaturing purification of 5'-dimethoxytritylated oligonucleotides that ensures that separation of tritylated and non-tritylated species will not be complicated by strand association. Fully denaturing conditions are produced by the use of tetraethylammonium hydroxide, which is a basic reagent with ion-pairing properties similar to triethylammonium acetate. The method also includes two other convenient features: a) the option of loading the crude oligonucleotide without removing concentrated ammonium hydroxide and b) detritylation on the column with separation of dimethoxytrityl alcohol.

Base Sequence↗
PubMed1993

Induction of micronuclei in peripheral blood lymphocytes of patients treated for rheumatoid or osteo-arthritis of the knee with dysprosium-165 hydroxide macroaggregates or yttrium-90 silicate.

The advantages of radiation synovectomy, using preparations containing dysprosium-165 (Dy-165), over conventional materials based on yttrium-90 (Y-90) include a more ideal spectrum of decay energies, and a much shorter half-life permitting quicker and more efficient treatment. A new therapeutic agent, Dy-165 hydroxide macroaggregates, has been developed for the treatment of arthritis making use of these advantages. As part of a clinical trial of this material 42 patients were examined for micronucleus frequency in their peripheral blood lymphocytes prior to, and 2 weeks after, radiation synovectomy using Dy-165 hydroxide macroaggregates or Y-90 silicate. In the majority of patients from each treatment group no significant increase in micronucleus frequency was observed. This indicates that in these cases leakage of material from the site of treatment was not resulting in detectable irradiation of circulating cells irrespective of the choice of radiopharmaceutical. The maximum increase in micronucleus frequency observed corresponded to a radiation dose to circulating cells of approximately 0.3 Gray.

Adult↗
PubMed1998

Comparative study of tolerability and efficacy of iron protein succinylate versus iron hydroxide polymaltose complex in the treatment of iron deficiency in children.

One-hundred children, 48 males and 52 females, mean age +/- SD 39.9 +/- 28.2 months (range 12 to 113) with sideropenia or sideropenic anemia were randomly divided into 2 groups of 50 patients each (groups A and B) and were treated with iron protein succinylate (group A) or iron hydroxide polymaltose complex (group B). Patients of both groups received 4 mg/kg elemental iron, maximally 80 mg daily, for 2 months. Side-effects of therapy and laboratory values (RBC, hematocrit, hemoglobin, MCV, serum iron, total iron binding capacity, and ferritin) were registered before treatment, 30 days after the beginning of therapy as well as after 60 days in order to evaluate tolerability and efficacy of the drugs. Both drugs were well tolerated and showed only few adverse reactions, which were comparable in severity and frequency. Iron protein succinylate led not only to a faster increase of hemoglobin, hematocrit, MCV, serum iron, and ferritin than iron hydroxide polymaltose complex, but the laboratory values remained higher in group A than in B even after 2 months of treatment.

Abdominal Pain↗
PubMed1998

Accumulation and metabolism of low density lipoprotein-derived cholesteryl linoleate hydroperoxide and hydroxide by macrophages.

Cholesteryl linoleate hydroperoxide (CLOOH) and hydroxide (CLOH) are present in human atheroma. The intracellular metabolism of low density lipoprotein (LDL)-derived CLOOH and CLOH remain undefined because extensive free radical-mediated LDL oxidation, which modifies LDL apolipoprotein B sufficiently to allow endocytosis by the scavenger receptor (ScR), also degrades CLOOH and CLOH. This problem was approached by first acetylating LDL lysine residues (AcLDL) to achieve protein modification, then exposing AcLDL to the aqueous radical donor 2,2'-azobis(2-amidinopropane) HCl (AAPH), to generate mildly oxidized AcLDL (OxAcLDL). Murine peritoneal macrophages incubated with OxAcLDL accumulated large quantities of CE and small, non-toxic quantities of CLOOH and CLOH in a time- and concentration-dependent manner, and accumulation was inhibited by fucoidin. Inhibition of acyl CoA: cholesterol acyltransferase during loading did not inhibit the accumulation of either CLOOH or CLOH, whereas NH4Cl decreased intracellular clearance of accumulated CLOOH from 68.3 +/- 1.7% to 35.3 +/- 1.0% over 12 h, suggesting lysosomal or pre-lysosomal accumulation. Intracellular clearance of unoxidized lipoprotein-derived CE decreased from 84.0 +/- 5.9% to 43.1 +/- 2.3% over 12 h when cells were loaded with AcLDL or OxAcLDL, respectively. Aggregation of mildly oxidized LDL, even without acetylation, also promoted cellular accumulation of CLOOH and CLOH. We conclude that intracellular accumulation of cholesteryl linoleate hydroperoxide and cholesteryl linoleate hydroxide can follow charge modification or aggregation of mildly oxidized LDL, and that LDL-derived oxidation products may inhibit hydrolysis of LDL-derived CE in foam cell macrophages.

Acetylation↗
PubMedDate not supplied

Concentration of simple aldehydes by sulfite-containing double-layer hydroxide minerals: implications for biopoesis.

Environmental conditions play an important role in conceptual studies of prebiotically relevant chemical reactions that could have led to functional biomolecules. The necessary source compounds are likely to have been present in dilute solution, raising the question of how to achieve selective concentration and to reach activation. With the assumption of an initial 'RNA World', the questions of production, concentration, and interaction of aldehydes and aldehyde phosphates, potential precursors of sugar phosphates, come into the foreground. As a possible concentration process for simple, uncharged aldehydes, we investigated their adduct formation with sulfite ion bound in the interlayer of positively charged expanding-sheet-structure double-layer hydroxide minerals. Minerals of this type, initially with chloride as interlayer counter anion, have previously been shown to induce concentration and subsequent aldolization of aldehyde phosphates to form tetrose, pentose, and hexose phosphates. The reversible uptake of the simple aldehydes formaldehyde, glycolaldehyde, and glyceraldehyde by adduct formation with the immobilized sulfite ions is characterized by equilibrium constants of K=1.5, 9, and 11, respectively. This translates into an observable uptake at concentrations exceeding 50 mM.

Acetaldehyde↗
PubMed2006

Synthesis and properties of cordycepin intercalates of Mg-Al-nitrate layered double hydroxides.

Layered double hydroxides (LDHs) were investigated as cordycepin delivery nanocarriers for the first time in this study. Negatively charged biomolecule-cordycepin was intercalated in the gallery spaces of [Mg-Al-NO(3)] as the charge-compensating species, which was confirmed by the results of XRD, FT-IR, TEM, CZE and electrophoretic mobility. Cell experiment suggested that the new bio-LDH nanohybrid could prevent cordycepin decomposition by adenosine deaminase. This new formulation could possibly be used as a novel form cordycepin intravenous injection.

Adenosine Deaminase↗
PubMed2005

Preparation of layered double hydroxides and their applications as additives in polymers, as precursors to magnetic materials and in biology and medicine.

In recent years layered double hydroxides (LDHs), also known as hydrotalcite-like materials, have attracted considerable interest from both industry and academia. In this article, we discuss methods of preparing LDHs with an emphasis on the way in which particle size and morphology can be controlled with regard to specific target applications; scale-up of one such preparation procedure is also described. In addition, we review selected applications of LDHs developed by our own and other laboratories.

Aluminum Hydroxide↗
PubMed1976

Influence of magnesium and aluminum hydroxide mixture on chlordiazepoxide absorption.

Ten healthy male subjects ingested 25 mg of chlordiazepoxide hydrochloride (Librium) with 100 ml of water or with 100 ml of magnesium and aluminum hydroxide (Maalox) in a single-dose crossover study. Multiple venous blood samples drawn during the first 24 hr after each dose were assayed for concentrations of chlordiazepoxide and its major metabolite, desmethylchlordiazepoxide. The antacid prolonged the mean chlordiazepoxide absorption half-time from 11 to 24 min, and in 6 of 10 subjects delayed achievement of the peak blood concentration by from 0.5 to 3.0 hrs. The formation of desmethylclordiazepoxide was also slowed. The areas under the 24 hr blood concentration curve for chlordiazepoxide and for its metabolite were not influenced by the antacid. The apparent elimination half-life of chlordiazepoxide (8.4 and 8.2 hr) was not significantly affected. Administration of chlordiazepoxide with antacid reduces the rate of its absorption but does not alter the completeness of absorption or the apparent rate of elimination.

Adult↗
PubMed2004

Mg,Al layered double hydroxides with intercalated indomethacin: synthesis, characterization, and pharmacological study.

Magnesium aluminium layered double hydroxides (LDH) with a molar Mg/Al ratio of 2.0 have been prepared with intercalated indomethacin following two routes: reconstruction from a previously calcined Mg(2)Al-CO(3) LDH, and coprecipitation from the corresponding chlorides. The solids have been characterized by powder X-ray diffraction, FTIR, and (13)C CP/MAS NMR spectroscopies and thermal stability (differential thermal analysis and thermogravimetric analysis). Intercalation of the drug is attained by both routes; however, while coprecipitation leads to a single layered structure, contamination with another layered MgAl-CO(3) phase occurs by the reconstruction method. The amount of drug intercalated, as well as the height of the gallery, are larger by the coprecipitation than by the reconstruction one. The data obtained support a somewhat tilted, upwards orientation of the drug molecules forming an interdigited bilayer, in the case of the sample prepared by coprecipitation, with the carboxylate groups pointing towards the hydroxyl layers. However, in the case of the sample prepared by reconstruction, the molecules are forming a tilted, upwards monolayer. The solids prepared are stable up to 250 degrees C. Pharmacological studies in vivo show that intercalation of the drug in the LDH reduces the ulcerating damage of the drug.

Aluminum Hydroxide↗