ascorbic-acid and potassium-nitrate

The trace detection and forensic analysis of black powders and black powder substitutes, directly from wipe-based sample collections, was demonstrated using infrared thermal desorption (IRTD) coupled with direct analysis in real time mass spectrometry (DART-MS). Discrete 15 s heating ramps were generated, creating a thermal desorption profile that desorbed more volatile species (e.g., organic and semivolatile inorganic compounds) at lower temperatures (250-400 °C) and nonvolatile inorganic oxidizers at high temperatures (450-550 °C). Common inorganic components of black powders (e.g., sulfur and potassium nitrate) as well as the alternative and additional organic and inorganic components of common black powder substitutes (e.g., dicyandiamide, ascorbic acid, sodium benzoate, guanidine nitrate, and potassium perchlorate) were detected from polytetrafluoroethylene-coated fiberglass collection wipes with no additional sample preparation. IRTD-DART-MS enabled the direct detection of intact inorganic salt species as nitrate adducts (e.g., [KClO

Topics: Ascorbic Acid; Forensic Sciences; Guanidine; Guanidines; Humans; Mass Spectrometry; Nitrates; Perchlorates; Potassium Compounds; Powders; Sodium Benzoate; Spectrophotometry, Infrared; Sulfur; Temperature; Time Factors

To evaluate the effect of topically administered ascorbic acid on experimentally induced corneal neovascularization in the rat model.. Corneal chemical cauterization of 72 eyes in Long-Evans male rats was performed using silver nitrate/potassium nitrate sticks. Nine groups of eight eyes were used to evaluate eight concentrations of ascorbic acid with one group of eight eyes serving as a control. Topical instillation of 100 mg/ml non-pH-neutralized ascorbic acid was performed in one group while the remaining seven groups were evaluated using pH-neutralized ascorbic acid in concentrations of 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 microg/ml, and 250 microg/ml.. The percentage of corneal neovascularization and burn stimulus score was determined for all the eyes. The means of percent of corneal neovascularization in ascorbic acid 100 mg/ml (non-neutralized), 100 mg/ml, 50 mg/ml, 10 mg/ml, 5 mg/ml, 1 mg/ml, 500 microg/ml, 250 microg/ml, and control group were 17.50 +/- 12.80 (p = 0.001), 17.00 +/- 19.30 (p = 0.001), 15.25 +/- 13.26 (p = 0.001), 17.62 +/- 11.89 (p = 0.001), 28.87 +/- 23.08 (p = 0.001), 29.62 +/- 16.91 (p = 0.001), 60.12 +/- 8.50 (p = 0.04), 65.62 +/- 2.26 (p = 0.185), and 68.25 +/- 4.06, respectively (Tables 1 and 2). All animals had a burn score of 2+ or higher (Table 1).. Ascorbic acid applied in a topical solution appears to inhibit corneal neovascularization in the rat model of inflammatory neovascularization in concentrations in a dose-dependent manner. The optimal dose-effect relation was in our model found in concentrations between 1 mg and 500 microg/ml. At concentrations below 500 microg/ml there was no statistically significant inhibition in the degree of corneal neovascularization compared to control.

Topics: Administration, Topical; Angiogenesis Inhibitors; Animals; Antioxidants; Ascorbic Acid; Corneal Neovascularization; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Combinations; Hydrogen-Ion Concentration; Nitrates; Potassium Compounds; Rats; Rats, Long-Evans; Silver Nitrate

Ascorbic acid (AA) fulfils many essential functions in plants. It is a key antioxidant and an important reducing substrate for a number of enzymes. The effects of low AA on plant architecture and leaf ultrastructure were studied in Arabidopsis thaliana mutants, which have constitutively moderately low (vtc1) or very low (vtc2) leaf AA contents compared with the wild type. Shoot development was comparable in all accessions over the first 14 d of growth. The production of primary roots was slightly different in vtc1, vtc2, and wild-type plants. However, the most notable difference was that a high proportion of the primary roots of the vtc2 plants grown on soil had lost the wild-type responses to gravity. The vtc mutants showed the antagonistic interaction between nitrate and sugar in the regulation of lateral root (LR) development that was observed in the wild type. However, the vtc2 mutants produced greater numbers of longer LRs than wild-type or vtc1 plants at all levels of nitrate. At later stages of development, the vtc rosettes were smaller than those of the wild type and the leaves showed intracellular structural changes that are consistent with programmed cell death (PCD). PCD symptoms such as nuclear chromatin condensation, the presence of multivesicular bodies, and extensive degradation and disorganization of the grana stacks were observed in 8-week-old vtc2 leaves and in 10-week-old vtc1 leaves. The data presented here illustrate the importance of tissue AA contents in regulating whole plant morphology, cell structure, and development.

Topics: Antioxidants; Arabidopsis; Ascorbic Acid; Cell Death; Chloroplasts; Morphogenesis; Mutation; Nitrates; Plant Leaves; Plant Roots; Potassium Compounds; Seedlings; Sucrose

The effect of curing agents (nitrate, glucose, ascorbic acid and chloride) and physical parameters (temperature, water activity and pressure) on porcine muscle cathepsin D has been studied. Chloride (in the assayed range 0 to 75 g Cl-/L) showed a strong inhibitory effect. Nitrate (in the assayed range 0 to 800 mg/L) and high concentrations of ascorbic acid (4 to 8 g/L) slightly inhibited cathepsin D. However, its activity increased when glucose was added up to 4 g/L. Cathepsin D activity was maximal when incubated at 33 to 53 degrees C, was affected by a decrease in water activity and unaffected by pressure.

Topics: Animals; Ascorbic Acid; Cathepsin D; Food Preservation; Glucose; Meat; Muscles; Nitrates; Potassium Compounds; Sodium Chloride; Swine; Temperature

Topics: Animals; Ascorbic Acid; Campylobacter fetus; Cattle; Culture Media; Meat; Nitrates; Phosphates; Potassium Compounds; Sodium Chloride; Sodium Glutamate; Sodium Nitrite; Tissue Extracts

The kinetics and mechanism of the reduction of oxidized cytochrome c by ascorbate has been investigated in potassium nitrate, potassium 4-morpholineethanesulfonate (KMes), potassium sulfate and potassium ascorbate media. The results are consistent with simple second order electron transfer from ascorbate dianion to cytochrome c and do not support electron transfer from an ascorbate dianion bound to the protein of the cytochrome as recently proposed by Myer and Kumar. A rate constant of 8 X 10(5) M-1 X s-1 (25 degrees C, ionic strength, 0.1) was found for the electron-transfer step. This rate constant is essentially independent of the specific ions used in controlling ionic strength.

Topics: Alkanesulfonates; Alkanesulfonic Acids; Animals; Ascorbic Acid; Cytochrome c Group; Electron Transport; Horses; Kinetics; Morpholines; Myocardium; Nitrates; Oxidation-Reduction; Potassium Compounds; Solutions; Sulfates

Nitrate poisoning was induced in a cow by giving it 200 g potassium nitrate through a rumen fistula for three to four days in succession. The effect of treatment with methylene blue, ascorbic acid and menadione, administered intravenously in different dosages was assessed by measuring methaemoglobin as a percentage of total haemoglobin and comparing the results with those from the untreated cow. The results obtained indicate that ascorbic acid and menadione are unsuitable for treatment of methaemoglobinaemia in nitrate poisoned cattle, but treatment with methylene blue at 1 mg/kg body weight appears to be adequate.

Topics: Animals; Ascorbic Acid; Cattle; Cattle Diseases; Female; Hemostatics; Methemoglobinemia; Methylene Blue; Nitrates; Potassium Compounds; Vitamin K; Vitamin K 3