FT-IR product study of the reactions of NO3 radicals with ortho-, meta-, and para-cresol.

Product analyses of the NO3 radical-initiated oxidation of ortho-, meta-, and para-cresol have been performed in large-volume chamber systems at the University of Wuppertal (1080 L quartz glass reactor: QUAREC) and the European Photoreactor (EUPHORE), Valencia, Spain. The reaction of O3 with NO2 was used for the in situ generation of NO3 radicals in both QUAREC and EUPHORE. In the QUAREC experiments the gas-phase reaction of ortho-cresol isomer with NO3 yielded (11.5 ± 0.8) % 6-methyl-2-nitrophenol (6M2NP), (4.4 ± 0.3) % methyl-1,4-benzoquinone (MQUIN) and (77.2 ± 6.3) % HNO3. The reaction of NO3 radicals with meta-cresol yielded (21.2 ± 1.4) % 3-methyl-2-nitrophenol (3M2NP), (22.8 ± 1.8) % 3-methyl-4-nitrophenol (3M4NP), (23.5 ± 1.8) % 5-methyl-2-nitrophenol (5M2NP), (4.2 ± 0.7) % MQUIN and (72.3 ± 6.4) % HNO3. In the reaction of NO3 radicals with para-cresol, 4-methyl-2-nitrophenol (4M2NP) and HNO3 were identified as products with yields of (41.3 ± 3.7) % and (85.0 ± 10.2) %, respectively. In the EUPHORE chamber not all products were formed at levels above the detection limit, however, in cases where detection was possible similar product yields were observed. The product formation yields determined in both chambers are compared with available literature data and a gas-phase mechanism is proposed to explain the formation of the products observed from the reaction of NO3 and with cresol isomers.

Modern risk stratification in coronary heart disease.

The prevalence and impact of cardiovascular diseases in the world are growing. There are 2 million deaths due to cardiovascular disease each year in the European Union; the main cause of death being the coronary heart disease responsible for 16% of deaths in men and 15% in women. Prevalence of cardiovascular disease in Romania is estimated at 7 million people, of which 2.8 million have ischemic heart disease. In this epidemiological context, risk stratification is required for individualization of therapeutic strategies for each patient. The continuing evolution of the diagnosis and treatment techniques combines personalized medicine with the trend of therapeutic management leveling, based on guidelines and consensus, which are in constant update. The guidelines used in clinical practice have involved risk stratification and identification of patient groups in whom the risk-benefit ratio of using new diagnostic and therapeutic techniques has a positive value. Presence of several risk factors may indicate a more important total risk than the presence / significant increase from normal values of a single risk factor. Modern trends in risk stratification of patients with coronary heart disease are polarized between the use of simple data versus complex scores, traditional data versus new risk factors, generally valid scores versus personalized scores, depending on patient characteristics, type of coronary artery disease, with impact on the suggested therapy. All known information and techniques can be integrated in a complex system of risk assessment. The current trend in risk assessment is to identify coronary artery disease in early forms, before clinical manifestation, and to guide therapy, particularly in patients with intermediate risk, which can be classified in another class of risk based on new obtained information.

Atmospheric photooxidation of fluoroacetates as a source of fluorocarboxylic acids.

A 1080 L environmental chamber with in situ FTIR spectroscopy detection was used to study the product distribution and the mechanism of the Cl-initiated photooxidation of a series of fluoroacetates. The gas-phase reactions of Cl atoms with ethyl trifluoroacetate (CF(3)C(O)OCH(2)CH(3)), methyl trifluoroacetate (CF(3)C(O)OCH(3)), and methyl difluoroacetate (CF(2)HC(O)OCH(3)) were investigated at 296 +/- 2 K and atmospheric pressure (approximately 760 Torr) of synthetic air. The fate of the fluoroalkoxy radicals formed in the reaction with Cl atoms mainly occurs through (i) an H-atom abstraction by reaction with O(2,) to produce the corresponding fluoroanhydride and (ii) an alpha-ester rearrangement via a five-membered ring intermediate to give the corresponding fluoroacetic acid. The yields of fluoroacids (CF(2)XC(O)OH, with X = H, F) obtained were as follows: 78 +/- 5, 23 +/- 2, and 30 +/- 5% for CF(3)C(O)OCH(2)CH(3), CF(3)C(O)OCH(3), and CF(2)HC(O)OCH(3,), respectively. Yields of