Potassium dichromate

About: Potassium dichromate is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 18967 citations. The topic is also known as: Potassium dichromate(VI) & Chromium potassium oxide.

A Golgi-electron microscope method for insect nervous tissue.

Abstract: Golgi's light microscopic method of selective silver impregnation for nervous tissue combined with electron microscopy appears to offer a promising method for working out the detailed anatomy of individual neurons and their connections. Insect nervous tissue is fixed in a mixture of 2% paraformaldehyde and 21/2% glutaraldehyde in Millonig's buffer (pH 7.2) before postfixation for 12 hours in a solution brought to pH 7.2 with KOH containing 2% potassium dichromate, 1% osmium tetroxide and 2% D-glucose. The tissue is then transferred to a solution of 4% potassium dichromate for 1 day; and for 1-2 days to a 0.75% silver nitrate solution. After dehydration and embedding in Araldite, 50μm sections am made. Areas of interest are cut from these sections and re-embedded in silicone molds. Ultrathin sections are then cut and stained with uranyl acetate and lead citrate. The Golgi method described here gives good results at the level of both light and electron microscopy.

The beneficial effects of thyroxine on nephrotoxic acute renal failure in the rat.

Abstract: We were able to confirm previous studies demonstrating that administration of thyroxine is capable of ameliorating the severity of acute nephrotoxic renal failure in the rat. Nephrotoxic acute renal failure was induced by the subcutaneous injection of potassium dichromate (6.25 mg/kg) into Sprague-Dawley rats. Twenty-four hours after this injection, rats received an intraperitoneal injection of either thyroxine (80 micrograms/kg body wt) or normal saline. Forty-eight hours after the potassium dichromate injection, renal clearance studies were performed. Inulin clearance was significantly higher in the thyroxine-treated than in the saline-treated acute renal failure rats: 1.12 +/- 0.13 (SEM) mL/g versus 0.75 +/- 0.07 mL/min/g kidney wt (P = 0.025). Thyroxine treatment also effected an increase of p-aminohippuric acid extraction from 0.23 +/- 0.03 to 0.33 +/- 0.02 (P = 0.011) and a decrease in the fractional excretion of sodium from 0.38 +/- 0.21 to 0.11 +/- 0.03% (P = 0.037 by Mann-Whitney U test). In order to investigate one potential mechanism of the beneficial effect of thyroxine we studied renal tubular regeneration in this model of acute renal failure. Renal cortical uptake of labeled thymidine into DNA was significantly increased 48 h after the injection of potassium dichromate, and thyroxine administration further enhanced this repair process: 53.9 +/- 3.6 versus 81.4 +/- 5.3 dpm/200 pg of DNA (P = 0.0033).

Spiral Crystal Growth of Potassium Dichromate in Gelatin

Abstract: Huge spiral crystals of potassium dichromate (K 2 Cr 2 O 7 ) have been found to grow three-dimensionally in a gelatin medium when gelatin containing K 2 Cr 2 O 7 was dried slowly in a test tube at a low temperature. These spirals were all right-handed, and their widths, axial pitches and lengths were 2–3 mm, 5–6 mm and 20–25 mm, respectively. When the gelatin concentration in the medium was decreased, ordinary platelike crystals were observed to grow, instead of the spiral crystals. To the best of our knowledge, inorganic compounds such as K 2 Cr 2 O 7 have so far not been reported to form such huge spiral crystals. It is conjectured that collagen molecules, which compose the gelatin medium and have right-handed triple helix structure lead to the growth of spiral crystals.

Method and composition for acidizing subterranean formations

Abstract: Gelled acidic compositions suitable for either matrix acidizing or fracture-acidizing of subterranean formations, and methods of using said compositions in acidizing operations, are provided. Said compositions comprise water, a water-dispersible polymer of acrylamide, an acid, and a flavotannin gelling agent. In a preferred embodiment, said compositions also comprise a gelation promoter, e.g., sodium dichromate or potassium dichromate.