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PubMed2005

Ribbon- and boardlike nanostructures of nickel hydroxide: synthesis, characterization, and electrochemical properties.

We report the synthesis, characterization, and electrochemistry properties of ribbon- and boardlike nanostructures of nickel hydroxide, which crystallize in different phases. The ribbonlike nanostructures (nanoribbons) of nickel hydroxide were synthesized by treating amorphous alpha-Ni(OH)2 with high concentrations of nickel sulfate. These nanoribbons crystallized in a new phase had typical widths of 5-25 nm, thicknesses of 3-9 nm, and lengths of up to a few micrometers. After further treatment in alkali at 60 degrees C, the nanoribbons converted to boardlike nanostructures (nanoboards), which crystallized in the beta-phase with the average length-width-thickness ratio of 20:6:1. The crystal structures, Raman spectra, and electrochemical properties of these nanostructures of nickel hydroxide are described in this paper. For comparison, the amorphous alpha-Ni(OH)2 has also been investigated. Moreover, the intermediate product between the nanoribbons and the nanoboards displays a unique structure, which implied an interesting transformation process. The nanoribbons with the new phase show some unique features in Raman spectra, two new peaks located at 3534 and 3592 cm(-1) in the OH stretching region, indicating the new chemical environment of the hydroxyl groups. The nanoboards exhibit the highest specific capacity, which is close to the theoretical capacity of beta-Ni(OH)2. It suggests that the boardlike nanostructure is helpful in improving the electrochemical performance of nickel hydroxide. Because of their unique structures and properties, the nanoribbons and nanoboards of nickel hydroxide may give a new perspective for applications in the areas of catalysts and rechargeable batteries.

Journal Article↗

PubMed1983

A morphological study of ferritin synthesis in macrophages with ingested ferric hydroxide-potassium polyvinyl sulfate complexes.

A ferric hydroxide-polyvinyl sulfate colloidal solution (Fe-PVS), prepared by mixing potassium polyvinyl sulfate (PVSK) and ferric hydroxide colloidal solution was used to study ferritin synthesis in rat peritoneal macrophages. The colloidal particles had spherical electron opaque ferric hydroxide cores with diameters of about 250 nm surrounded by radially arranged fibrous PVS molecules. They also had strong negative electric charges. Fe-PVS particles injected into the peritoneal cavity were taken up by the macrophages then disintegrated rapidly. In the phagolysosomes the electron opaque ferric hydroxide cores of Fe-PVS were denuded of their PVS frames then decomposed into small 5-6 nm granules 24 to 48 h after injection. These small granules were released from the lysosomes into the hyaloplasm and the myelin figures were found in the lysosomal vacuoles. No reaccumulation of granules in lysosomes was found even 3 months later. The intracellular distribution of ferritin in macrophages demonstrated by the immunocytochemical method showed a pattern similar to that of the small granules formed by the disintegration of Fe-PVS. This means that in rat peritoneal macrophages that contain ingested Fe-PVS particles ferritin first is synthesized in phagolysosomes by the ferric hydroxide cores that conjugate with apoferritin or protein subunits then they are dispersed into the cytoplasm. Two possible pathways for the biosynthesis of ferritin are discussed.

Animals↗

PubMed2006

Effects of ferric hydroxide on methanogenesis from lipids and long-chain fatty acids in anaerobic digestion.

The addition of ferric hydroxide to sludge from a municipal anaerobic digester stimulated the rate of methanogenesis from canola oil when the initial oil concentration was high (4600 mg/L; P < 0.002), but not when it was low (920 mg/L; P > 0.05). Similar trends were observed when oleic acid, a fatty acid that is a major component of canola oil triglycerides, was provided, but the effects were statistically significant only when the initial concentration of ferric hydroxide was also high (18 g/L; P = 0.015). Iron reduction occurred when ferric hydroxide was added to microcosms containing anaerobic digester sludge, but the extent of ferrous iron production was much less in acetate-amended microcosms than in those that were provided with canola oil or oleic acid. Methanogenesis and acetate consumption were completely inhibited when the initial acetate concentration was approximately 5000 mg/L, regardless of the initial ferric hydroxide concentration. The main effect of ferric hydroxide in this system appears to have been a result of stimulation of the rate of fatty acid oxidation.

Anaerobiosis↗

PubMed1978

Bioassay of triphenyltin hydroxide for possible carcinogenicity.

A bioassay of triphenyltin hydroxide for possible carcinogenicity was conducted using Fischer 344 rats and B6C3F1 mice. Triphenyltin hydroxide was administered in the feed, at either of two concentrations, to groups of 50 male and 50 female animals of each species. The high and low concentrations of triphenyltin hydroxide were, respectively, 75 and 37.5 ppm for rats and mice. After a 78-week period of compound administration, there was an additional observation period of 26 weeks for both species. Twenty animals of each sex and species were placed on test as controls. For male mice, there was a significant positive association between dosage and mortality. In both species, however, adequate numbers of animals survived sufficiently long to be at risk from late-developing tumors. Except for a slight depression of mean body weight gain in male rats and female mice, compound-related mean body weight depression was not observed in either species. In female rats no significant accelerated mortality, retardation of growth, or other signs of toxicity were associated with the dietary administration of triphenyltin hydroxide. Therefore, it is possible that the compound was not administered at the maximum tolerated concentrations. No tumors occurred at a significantly higher incidence in dosed rats or mice than in controls. Under the conditions of this bioassay, there was no evidence for the carcinogenicity of triphenyltin hydroxide to Fischer 344 rats or B6C3F1 mice.

Journal Article↗

PubMed2003

Relationship between the degree of antigen adsorption to aluminum hydroxide adjuvant in interstitial fluid and antibody production.

The effect of the degree of adsorption after exposure to interstitial fluid on the immune response in mice to model vaccines containing ovalbumin, alpha casein or dephosphorylated alpha casein adsorbed to aluminum hydroxide adjuvant was studied. Ovalbumin and dephosphorylated alpha casein were adsorbed in the vaccine but were completely eluted when exposed to interstitial fluid for 4 h. The presence of aluminum hydroxide adjuvant in the vaccine produced immunopotentiation compared to a solution of the protein even though the protein desorbed rapidly upon subcutaneous administration. In contrast, alpha casein was completely adsorbed to aluminum hydroxide adjuvant in both the vaccine and upon exposure to interstitial fluid. Immunopotentiation by aluminum hydroxide adjuvant was also observed in this model vaccine compared to a solution of alpha casein. The results indicated that antigen presenting cells can take up desorbed antigen from interstitial fluid as well as antigen adsorbed to aluminum-containing adjuvants.

Adjuvants, Immunologic↗

PubMed2004

Apatite-forming ability of alginate fibers treated with calcium hydroxide solution.

Calcium alginate fibers were prepared by extruding an aqueous sodium alginate solution into an aqueous calcium chloride solution. The fibers were treated with a saturated aqueous calcium hydroxide solution for various periods and their apatite-forming ability was examined in a simulated body fluid (SBF). The calcium alginate fibers were treated with the aqueous calcium hydroxide solution for periods longer than five days formed apatite on their surfaces in SBF, and their apatite-forming ability improved with increasing calcium hydroxide treatment time. The amount of calcium ions released from the fibers also increased with increasing calcium hydroxide treatment time, resulting in acceleration of nucleation and growth of apatite on the fiber surfaces. The resultant apatite-alginate fiber composite is expected to be useful as a flexible bioactive bone-repairing material.

Alginates↗

PubMed2001

PH changes at the surface of root dentin after intracanal dressing with calcium oxide and calcium hydroxide.

This study was designed to compare pH changes at the cervical and apical surfaces of root dentin after canal obturation with calcium oxide or calcium hydroxide pastes. The effect of the exposure to CO2 on the pH at the root surface also was assessed for both materials. Thirty-six extracted human canines were selected and instrumented. Wells 1 mm deep x 1.5 mm in diameter were drilled in the cervical and apical regions of the buccal root surface. The teeth were randomly divided into two groups and obturated with either calcium hydroxide or calcium oxide. pH was measured in the cervical and apical wells at varying time intervals until 48 days posttreatment. After pH measurement on day 48 the vials were flushed with CO2 and the pH measured again at days 53 and 68. The results indicated a similar pattern of pH increase after treatment with either calcium oxide or calcium hydroxide. pH dropped significantly after exposure to CO2 in both groups. This study demonstrated that hydroxyl ions produced when calcium oxide reacts with water diffuse through the dentinal tubules to the surface of the root in a manner similar to hydroxyl ions from calcium hydroxide.

Analysis of Variance↗

PubMed2003

Release of hydroxyl ions from calcium hydroxide preparations used in endodontic treatment.

PURPOSE: The purpose of our study was to compare the in vitro release of hydroxyl ions from several calcium hydroxide preparations used in endodontic treatment. MATERIAL AND METHODS: Equal quantities of the materials--nonsetting (pure calcium hydroxide, Biopulp, Calcicure), setting--canal sealers (Sealapex, Apexit) and points were placed in dialysis tubes which were then immersed in deionized water. The release of hydroxyl ions from the preparations was measured by the median pH of the deionized water used for dialysis, by means of a pH-meter. The results of our study were analyzed by means of Tukey's reasonable correlation. Significance difference (one-way variance analysis ANOVA) and Pearson's linear correlation coefficient (r2). RESULTS: Nonsetting preparations of calcium hydroxide have a significantly higher capability of hydroxyl ions release in comparison with sealers and points, irrespective of time (p < 0.05). Sealapex and "plus" points released hydroxyl ions to a much greater extent than both Apexit and "regular" points at most periods of the experiment (p < 0.05). Apexit released significantly more of hydroxyl ions than "regular" points, and Sealapex more than "plus" points in the later periods of the experiment (p < 0.05). The pH values of dialysis samples of all materials correlated positively with time and the pH. Almost all materials reached a maximum on the 8-th day of the experiment. CONCLUSIONS: To achieve maximum concentration of hydroxyl ions in tissues: for temporary root fillings nonsetting preparations of calcium hydroxide should be chosen rather than points and they should be placed for at least one week, for permanent root fillings it is more recommended to use Sealapex than Apexit as a sealer.

Calcium Hydroxide↗

PubMed1991

Investigation of the possible influence of the absorption of vinpocetine with concomitant application of magnesium-aluminium-hydroxide gel.

The concomitant application of magnesium-aluminium-hydroxide gel does not influence the absorption of vinpocetine (CAS 42971-09-5). The pharmacokinetics of vinpocetine under the influence of a concomitant application of magnesium-aluminium-hydroxide gel was investigated. 18 healthy male volunteers were included in the study. Vinpocetine was administered in the galenic form of a film-coated tablet in a dosage of 20 mg t.i.d. over 10 days. On days 5 and 6 of the study, blood samples were taken at 16 different moments over 24 h and analyzed as to their vinpocetine content. Starting with the 6th day of the study, the patients were administered in addition 1 sachet of an magnesium-aluminium-hydroxide gel 4 times a day. On day 9 of the trial, blood samples were taken again over 24 h. The parameters examined were AUC, Cmin, Cmax, tmax and Mean Residence Time. The results as to these parameters of day 5 were compared with those of day 9. As a further parameter, apovincaminic acid plasma levels were determined. There was no difference as to the vinpocetine amount absorbed with or without concomitant application of magnesium-aluminium-hydroxide gel. Apovincaminic acid plasma levels were lowered by approx. 11% when associated with the antacid.

Adult↗

PubMed1996

Comparison of the effects of ranitidine effervescent tablets and magnesium hydroxide-aluminium oxide on intragastric acidity. A single-centre, randomised, open cross-over study.

In previous studies measuring intragastric pH in healthy volunteers it was shown that there was a faster onset of action with ranitidine (CAS 66357-35-5) 300 mg effervescent tablets (Zantac) compared to standard tablets. In a single-centre, randomised, open cross-over study the pH-values obtained over 6 h following the administration of one ranitidine 150 mg effervescent tablet were compared with those after aluminium oxide-magnesium hydroxide (algeldrate, CAS 1330-44-5, Al-Mg-hydroxide) 10 ml and placebo in healthy volunteers. 24 healthy male subjects between 19 and 32 years of age entered the study, 19 subjects were available for all three measurements. After an overnight fast, intragastric pH was monitored for 7 h using a glass electrode and a digital data recorder. The time in % during which the pH was > or = 3.5 and the area under the curve of the obtained pH-curves were compared. There was a highly statistically significant difference between ranitidine effervescent tablets versus Al-Mg-hydroxide and placebo whereas there was no such difference between Al-Mg-hydroxide and placebo. The onset of action of ranitidine effervescent tablets was almost immediate. It is concluded that there was a clear superiority of ranitidine effervescent tablets in healthy volunteers and it is suggested that pH-metry in patients with acidity-related diseases should be investigated for a better understanding of the function of effervescent tablets.

Adult↗

PubMed2004

Flow cytometry: interesting tool for studying binding behavior of DNA on inorganic layered double hydroxide (LDH).

BACKGROUND: A new method was established to characterize the binding kinetics of DNA toward layered double hydroxides (LDHs). The setup consisted of a newly developed sampling tube that allows the injection of analyte during the flow cytometric measurement. METHODS: Layered double hydroxides consist of cationic metal hydroxide layers and exchangeable interlayer anions. This negatively charged structure permits biomolecules such as DNA to adsorb, and a so-called DNA-LDH hybrid is formed. The hydroxide layers can be removed in acidic media and the DNA will be released. CERATOFIX (a registered trademark of Sud-Chemie AG NA that belongs to the family of LDHs, produced by Sud-Chemie AG). The chemical structure can be summarized as [Mg(2)Al(OH)(6)](CO(3))(0.5). The binding capacity and kinetic characteristics of different types of CERATOFIX NA for a model DNA was determined by flow cytometry. RESULTS: The static binding capacities of the different LDHs were determined after 1- and 16-h incubation with DNA solution, showing different binding patterns between the LDH materials. The binding kinetics were revealed by flow cytometric measurements in short-term and long-term kinetic experiments, showing that the majority of DNA adsorbs within the first 60 s. CONCLUSIONS: DNA removal from cell culture supernatants is one of the major concerns in downstream processing. Due to the anion exchange capabilities of LDHs it seemed a very interesting approach to use these materials for binding of DNA for elimination purposes.

Adsorption↗

PubMed2006

Effect of alkali metal hydroxides on the enantioseparation of amines using di-O-isopropylidene-keto-L-gulonic acid as the selector in NACE.

The present work demonstrates the importance of the ionic composition in the BGE for enantioseparation. (-)-2,3:4,6-di-O-Isopropylidene-2-keto-L-gulonic acid ((-)-DIKGA) has been used as the chiral selector in methanolic and ethanolic BGEs. The influence of added alkali metal hydroxides on the EOF and the chiral separation of amines (atenolol, isoprenaline, pindolol and propranolol) have been studied. The ion-pair formation constants in ethanol were determined by precision conductometry for the enantiomers of pindolol with (-)-DIKGA, for Li(+), Na(+) and Cs(+) with (-)-DIKGA, and also for the corresponding alkali metal hydroxides. The effective mobilities and the enantiomeric mobility differences were affected by the type of alkali metal hydroxide (LiOH, NaOH, KOH, RbOH or CsOH) added to the BGE. The effective mobility and mobility difference were increased with decrease in solvated radius of the alkali metal cation. These differences could partly be correlated to the ion-pair formation constants of the alkali metal cations with the chiral selector, affecting the equilibrium concentration of the free selector. The electroosmosis was also affected by the alkali metal hydroxide added to the BGE. The cathodic electroosmosis decreased with decreasing solvated radius of the alkali metal cation added to the BGE. Interestingly, the cathodic EOF was even reversed, i.e. became anodic in the ethanolic BGEs containing KOH, RbOH or CsOH and the methanolic ones with RbOH and CsOH.

Amines↗

PubMed1977

pH-stat titration of aluminum hydroxide gel.

The pH-stat titration of aluminum hydroxide gel was evaluated and was affected by pH, temperature, concentration, and ionic strength. Control of these parameters resulted in a highly sensitive and reproducible in vitro antacid test. The utility of the pH-stat test was illustrated by monitoring the aging of several carbonate-containing aluminum hydroxide gels and by comparing the antacid properties as measured by the pH-stat titration, the acid-consuming capacity, the Rossett-Rice test, and the test proposed by the food and Drug Administration Drug Evaluation Panel. The pH-stat titration also was useful for relatively nonreactive aluminum hydroxide gels. The use of sodium fluoride as the reaction medium extended the capability of the pH-stat titration to monitor the aging of chloride-containing gels. The pH-stat titrigram was interpreted in terms of a previously published polymer model of the structure of a chloride-containing aluminum hydroxide gel. The acid reactivity of relatively nonreactive gel is believed to be due totally to the chemical neutralization of acid, because the milliequivalents of aluminum ion appearing in solution is the same as the milliequivalents of acid neutralized throughout the ph-stat titration.

Adsorption↗

PubMed1981

Effect of adsorbed carbonate on surface charge characteristics and physical properties of aluminum hydroxide gel.

A titration procedure was used to determine the zero point of charge of a number of chloride-containing aluminum hydroxide gels and aluminum hydroxycarbonate gels. The surface charge characteristics of aluminum hydroxide gel were determined by both hydroxyls and the surface density of specifically adsorbed carbonate anion. The wide range of zero point of charge values reported for aluminum hydroxide is thought to be due to the presence of specifically adsorbed anions such as carbonate. The effect of ionic strength on the pH of aluminum hydroxide gel is important during washing since the ease of electrolyte removal is related to surface charge. Viscosity and sedimentation characteristics are related to the relationship between the zero point of charge and bulk pH. Maximum possibility was observed when the bulk pH was adjusted to the zero point of charge.

Adsorption↗

PubMed1983

Acetaminophen-aluminum hydroxide interaction in rabbits.

Acetaminophen-aluminum hydroxide interaction was investigated in a crossover study using six rabbits. Blood samples were collected at various time intervals for up to 6 hr following the oral administration of acetaminophen alone or in combination with aluminum hydroxide. Aluminum hydroxide at a 40-mg/kg dose did not appear to affect the rate and extent of acetaminophen absorption. The influence of aluminum hydroxide on gastric emptying could be compromised by gastric absorption of acetaminophen, resulting in a negligible effect on the overall bioavailability of acetaminophen.

Acetaminophen↗

PubMed1991

Differential effects of sodium bicarbonate and aluminium hydroxide on the absorption and activity of glipizide.

The effects of sodium bicarbonate and aluminium hydroxide on the absorption and activity of glipizide have been studied in healthy volunteers in two randomized cross-over trials. After an overnight fast, 5 mg glipizide was given either with 150 ml water or with water containing 3.0 g sodium bicarbonate or 1.0 g aluminium hydroxide. Sodium bicarbonate significantly increased the AUC of plasma glipizide from 0 to 0.5 h, 0 to 1 h, and from 0 to 2 h (six-, four- and twofold, respectively). The time to peak concentration (tmax) fell from 2.5 h during the control phase to 1.0 h during the sodium bicarbonate phase. The absorption half-life (t1/2a), lag time and mean residence time (MRT) were also significantly decreased. No significant change in peak plasma concentration (Cmax), total AUC or elimination half-life (t1/2) was noted. The decremental plasma glucose areas from 0 to 1 h and 0 to 2 h were significantly larger (80% and 50%, respectively) than during the control phase. The maximal decrease in glucose was 50% greater during the sodium bicarbonate phase, and the time to reach it was reduced by 35 min. Aluminium hydroxide had no significant effects on the rate or extent of absorption of glipizide, and the glucose response also remained unaffected. It is concluded that the concomitant ingestion of sodium bicarbonate and glipizide may result in accelerated absorption of glipizide and an increased effect on glucose. A common dose of aluminium hydroxide did not appear to affect the absorption of glipizide.

Adult↗

PubMed1986

Possible role of sulfhydryls in mucosal protection induced by aluminum hydroxide.

The involvement of sulfhydryl-containing compounds was investigated in the cytoprotective effect of certain antacids against ethanol-induced gastric mucosal damage in the rat. Not only the protective effect of a sulfhydryl containing compound, N-acetylcysteine, was abolished after pretreatment with N-ethylmaleimide, but also the adaptive cytoprotection induced by 20% ethanol. Pretreatment of the animals with the cyclooxygenase inhibitor indomethacin or with the thiol reagent N-ethylmaleimide significantly diminished the cytoprotection evoked by aluminum hydroxide. However, the protective effect of aluminium hydroxide could only be totally abolished by pretreatment with the combination of indomethacin and N-ethylmaleimide. The present results suggest the additional role of sulfhydryl-containing compounds localized in the gastric mucosa in the cytoprotection induced by a mild irritant or by aluminium hydroxide and aluminium hydroxide-containing antacids as well.

Acetylcysteine↗

PubMed1988

Effect of calcium carbonate and aluminum hydroxide on human intestinal function.

The effect of calcium carbonate (6 g daily) and of aluminum hydroxide (Amphojel, 7.2 g daily) on human gastrointestinal function was examined because these popular antacids have a documented effect on fecal fat, an undocumented association with constipation, and a putative ability to ameliorate cocarcinogenic effects of bile acids and fatty acids on colonic mucosa. Intake-output studies were conducted over periods of three weeks during which time dietary intake was controlled (20 g fiber daily), and the order of treatment (control, calcium carbonate, aluminum hydroxide) was randomized. Neither calcium carbonate nor aluminum hydroxide altered the mean intestinal transit time of eight subjects. Calcium carbonate increased daily output of feces from 106 +/- 30 (SD) to 131 +/- 41 g, of fecal fatty acids from 7.9 +/- 1.4 to 16.8 +/- 5.4 mmol, and of fecal 3 alpha-hydroxy-bile acids from 411 +/- 223 to 769 +/- 505 mumol. Aluminum hydroxide increased daily output of feces to 143 +/- 43 g, of fecal fatty acids to 12.4 +/- 5 mmol, and of fecal bile acids to 735 +/- 592 mumol. Both Ca2+ and Al3+ precipitated deoxycholate when these ions were incubated in vitro. These observations help to explain how these two antacids may lower blood lipids and ameliorate the effects of fecal bile acids and fatty acids on colonic mucosa.

Aluminum Hydroxide↗