program prior to designing and conducting toxicology studies. The purpose of the research concept document is to outline the general elements of a research program that would address the specific public health concerns that prompted the nomination of the substance or issue for study. It may also encompass substance-specific studies that address larger public health issues or topics in toxicolog...

The cytotoxic chloroform fraction of Euphorbia aellenii afforded two cycloartane type triterpenes — cycloart-25-en-3,24-diol (1) and 24-methylene-cycloartan-3-ol (2) — for the first time from this plant. Preparation of cycloartane derivatives, 3, 24-O-diacetyl-cycloart-25-en as compound 3 and 3-O-acetyl-24-methylene-cycloartan (4) were conducted by acetylating of 1 and 2, respectively. The ...

The cytotoxic chloroform fraction of Euphorbia aellenii afforded two cycloartane type triterpenes — cycloart-25-en-3,24-diol (1) and 24-methylene-cycloartan-3-ol (2) — for the first time from this plant. Preparation of cycloartane derivatives, 3, 24-O-diacetyl-cycloart-25-en as compound 3 and 3-O-acetyl-24-methylene-cycloartan (4) were conducted by acetylating of 1 and 2, respectively. The ...

Automated and manual direct methods for the determination of urea in blood or serum are described. These methods determine urea by the colored product formed when urea, in relatively weak acid solution, reacts with diacetyl monoxime in the presence of thiosemicarbazide and ferric ion. Results are compared with those obtained by urease conversion of urea to ammonia and measurement of the ammonia...

some 3, 5-diacyl or 3,5-diester 1,4-dihydropyridines were oxidized to the corresponding pyridine derivatives using hydrogen peroxide in aqueous ethanol in the presence of potassium bromide and acetic acid as the catalysts. the reaction was carried out in ethanol and products were isolated in high to excellent yields. however, oxidation of 3,5-diacetyl 1,4-dihydropyridines is slower than 3,5-die...

Nasal dosimetry models, including physiologically based pharmacokinetic (PBPK) models, computational fluid dynamics (CFD) models, and hybrid CFD-PBPK models, have played a prominent role in inhalation toxicology and the risk assessment of inhaled gases. Although different in their approach, their goals are similar: to accurately describe tissue dosimetry of inhaled gases in an anatomically accu...

the cytotoxic chloroform fraction of euphorbia aellenii afforded two cycloartane type triterpenes — cycloart-25-en-3,24-diol (1) and 24-methylene-cycloartan-3-ol (2) — for the first time from this plant. preparation of cycloartane derivatives, 3, 24-o-diacetyl-cycloart-25-en as compound 3 and 3-o-acetyl-24-methylene-cycloartan (4) were conducted by acetylating of 1 and 2, respectively. the ...