Showing papers on "Potassium dichromate published in 1979"
TL;DR: In 12 cases an etiological connection could be traced between the oral symptoms and the denture base, indicating that contact sensitivity to base materials or to allergens and microbial antigens on the dentures plays a greater role in the pathogenesis of BMS in edentulous persons than previously suggested.
Abstract: The significance of sensitizing compounds in the denture base for the etiology of the burning mouth syndrome (HMS) has been studied in 53 denture-wearing persons, seven mules and 46 females. Epicutaneous patch tests were performed with standard concentrations of benzoyl peroxide, dibutylphthalate, dimethyl-p-toluidine, formaldehyde, hydroquinone, methylmethacrylate, p-phenylendiamine and with cadmium sulfate, potassium dichromate, cobalt chloride and nickel sulfate. Furthermore, patch testing was performed with filings from the denture mixed with the patient's own saliva. In cases with an inflamed oral mucosa, the presence of hyphae of Candida albicans was assessed by a smear technique. Positive skin reactions were observed in 15 persons to dimethyl-p-toluidine, hydroquinone, formaldehyde, methylmethacrylate, p-phenylendiamine, potassium dichromate, cobalt chloride and nickel sulfate, including three cases with reactions to filings from their dentures, and one patient, who after subsequent testing showed skin sensitivity to balsam of Peru. In 12 cases an etiological connection could be traced between the oral symptoms and the denture base, indicating that contact sensitivity to base materials or to allergens and microbial antigens on the denture plate plays a greater role in the pathogenesis of BMS in edentulous persons than previously suggested.
98 citations
Journal Article•
TL;DR: Caputi et al. as discussed by the authors used the chemical oxidation method for alcohol determination in wine after microdistillation of the samples, which is used routinely in many winery laboratories. But, analysts often experience a number of difficulties with the procedure, including using the distilling apparatus and indicator endpoint when dichromate is titrated with ferrous ammonium sulfate.
Abstract: The chemical oxidation method for alcohol determination in wine after microdistillation of the samples is used routinely in many winery laboratories. However, analysts often experience a number of difficulties with the procedure, including use of the distilling apparatus and indicator endpoint when dichromate is titrated with ferrous ammonium sulfate. The procedure was modified to avoid some of the problems. Five ml of wine were distilled in a Cash volatile acid still, operated to ensure complete condensation and recovery of alcohol distillate in a 50-ml volume. Two ml of distillate were oxidized at 60°C with 10 ml of dichromate solution (34 g potassium dichromate plus 325 ml sulfuric acid per liter). Alcohol concentration was determined spectrophotometrically at 600 nm, according to Caputi et al. [Am. J. Enol. Vitic. 19:160-5 (1968)]. The method as modified provided acceptable speed, precision, and accuracy for routine analysis of wine alcohol.
95 citations
TL;DR: A reliable Golgi-Kopsch variant is described and procedures for cutting, counterstaining, and handling sections are described.
53 citations
TL;DR: The time course of thymidine and deoxycytidine pool saturation suggests however that the effects of K2Cr2O7 on plasma membrane permeability are partially counterbalanced by modifications of pool size deriving from the concomitant alteration of steps of nucleoside metabolism separate from nucleosid uptake.
24 citations
TL;DR: Patients with apositive patch test to potassium dichromate 0.5% were retested after 4–7 years; 38 patients (79%) still had a positive patch test and in 72% of the cases a history of occupational exposure to chromates could be proved.
Abstract: Forty-eight patients with a positive patch test to potassium dichromate 0.5% were retested after 4-7 years; 38 patients (79%) still had a positive patch test. Chromate allergy seems to be persistent. In 72% of the cases a history of occupational exposure to chromates could be proved.
22 citations
TL;DR: In this paper, the emission and excitation spectra of K 2 Cr 2 O 7 crystals were first measured over the temperature range of 4-30 K. On the ground of these observations, the energy level scheme of transitions has been proposed and the vibrational analysis of the spectra has been carried out.
15 citations
TL;DR: In vanadates and potassium dichromate, triplet levels have been observed by luminescence measurements as mentioned in this paper, and the energy level schemes are in good agreement with each other and with calculated results.
15 citations
TL;DR: In this paper, both susceptibility to chemical oxidation and biodegradability of nitrobenzene were determined and both were shown to be resistant to chemical oxidization with potassium permanganate and partially oxidized with potassium dichromate.
Abstract: Both susceptibility to chemical oxidation and biodegradability of nitrobenzene are determined. Nitrobenzene is found to be resistant to chemical oxidation with potassium permanganate and is partially oxidized with potassium dichromate. Biodegradability is studied in a batch and in a flow-through system both with municipal and with artificially prepared wastewaters. Nitrobenzene present in municipal wastewater at 300 g/m3 concentrations is found to be biodegradable after adaptation of the biomass. In a flow-through system nitrobenzene is degradable at 400 g/m3 concentration. Concentrations exceeding 10 g/m3 inhibit the nitrification process.
15 citations
Journal Article•
11 citations
TL;DR: The reaction of o-allylphenols (1) with potassium dichromate dissolved in benzene using Adogen 464, a commerical mixture of methyl-trialkyl-(C8-C10)-ammonium chloride, or with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in ether affords the corresponding chrom-3-enes (3) in good yields as discussed by the authors.
Abstract: The reaction of o-allylphenols (1) with potassium dichromate dissolved in benzene using Adogen 464, a commerical mixture of methyl-trialkyl-(C8–C10)-ammonium chloride, or with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in ether affords the corresponding chrom-3-enes (3) in good yields.
10 citations
TL;DR: Stimulation of renal PAH excretion is possible in injured rats by repeated administrations of PAH and cyclopenthiazide, respectively, although the duration of injury is shortened whereas the intensity of the nephrotoxic effect is not changed.
01 Jan 1979
TL;DR: The titrimetric method of determining soil organic matter is preferable to the ignition loss method, as the need to estimate losses due to bound water is eliminated as mentioned in this paper, where the Walkley & Black redoxometric method uses potassium dichromate to oxidise carbon, after which excess dichromates is titrated against ferrous ammonium suplhate, giving a measure of the organic carbon digested.
Abstract: The titrimetric method of determining soil organic matter is preferable to the ignition loss method, as the need to estimate losses due to bound water is eliminated. The Walkley & Black redoxometric method uses potassium dichromate to oxidise carbon, after which excess dichromate is titrated against ferrous ammonium suplhate, giving a measure of the organic carbon digested. The procedure is described. Samples should not exceed 5g. Dry master samples should be crushed and ground to pass a 0.5 mm sieve. Moist fine grained cohesive soils can be kneaded instead of ground, a correction being made for moisture content. The figures obtained are influenced by the presence of manganese oxides in the soil. The oxidising effect of these can be determined by preliminary titration against a standard solution of ferrous ammonium sulphate. (TRRL)
Patent•
30 Apr 1979
TL;DR: In this paper, a bead-like structure and a Vickers hardness of from 1050 to 1500 was achieved in order to achieve a chromium layer having a beadlike structure, and an aqueous bath was employed which contained from 200 to 550 g/l of chromium trioxide, in addition to strontium sulphate, in the form of the malonate if required.
Abstract: In order to achieve a chromium layer having a bead-like structure and a Vickers hardness of from 1050 to 1500, an aqueous bath is employed which, in addition to from 200 to 550 g/l of chromium trioxide from 1 to 18 g/l of strontium sulphate from 2 to 30 g/l of potassium silicofluoride from 2 to 8 g/l of potassium dichromate, as the synergetic active compound contains from 4 to 50 g/l of 2,2-dichloromalonic acid, in the form of the malonate if required.
TL;DR: The chapter describes the extension of the use of potassium dichromate through a potentiometric end point for the assay of ascorbic acid with iodine, potassium iodate, and iodine monochloride using starch as indicator.
Abstract: Publisher Summary This chapter provides an overview of vitamin C (ascorbic acid). The assay of ascorbic acid with iodine, potassium iodate, potassium bromate, and iodine monochloride using starch as indicator is described in the chapter. Variamine blue is proposed as the indicator in the place of starch for the assay of ascorbic acid with iodine, potassium iodate, and iodine monochloride. Carbon tetrachloride or chloroform in the presence of mercuric chloride is also used for the detection of the equivalence point by extractive end point. In view of the advantages of potassium dichromate as a primary standard oxidimetric reagent, the usual difficulty encountered in the assay of ascorbic acid in colored solutions by visual methods, and the problem of stability of iodine in very dilute solutions, the chapter describes the extension of the use of potassium dichromate through a potentiometric end point. The principle involved in this procedure is that potassium dichromate when added to the titration mixture first reacts with potassium iodide, added in the beginning, liberating iodine that in turn reacts with ascorbic acid that is reduced to iodide. Oxalic acid is used as the catalyst to accelerate the reaction between potassium dichromate and potassium iodide.
TL;DR: In this paper, DSC and TG were applied to the study of reactions in solid mixtures of pentaerythritol (PE), 2,2-bis-(hydroxymethyl)-1,3-propanediol, and the oxidizing agents potassium dichromate and potassium permanganate.