Direct assessment of international consistency of standards for ground-level ozone: strategy and implementation toward metrological traceability network in Asia.

An international exercise to directly assess consistency of standards for ground-level ozone in East Asia was conducted as part of the East Asian Regional Experiment 2005 (EAREX 2005) in the framework of the Atmospheric Brown Clouds (ABC) project. Ten organizations collaboratively participated in the intercomparison. Four groups representing Japan, Korea, Hong Kong, and Taiwan made comparisons at the Gosan super observatory, Jeju Island, Korea, in March 2005, with ozone instruments calibrated to their national standards, and four Japanese groups made off-site comparisons with laboratory-level standards. All comparisons generally indicated good agreement with the standard reference photometer (SRP) 35, built by the National Institute of Standards and Technology (USA) and maintained by the National Institute for Environmental Studies (Japan). The assessment was expanded to measurement networks contributing to the World Meteorological Organization's Global Atmospheric Watch (WMO/GAW) program as part of off-site comparisons, and excellent agreement was achieved. These efforts contribute to propagating traceability of the national metrology standards among the atmospheric science community, to ensuring comparability of the existing ozone measurements, and to establishing an integrated network of air quality monitoring in Asia.

Coronary stenosis and steal phenomenon in coronary-pulmonary fistula--assessment with stress thallium tomography after coronary angioplasty and fistulectomy.

We present a 46-year-old male with unstable angina and bilateral coronary-to-pulmonary artery fistulae in whom reversible myocardial ischemia was detected by exercise-stress thallium-201 single-photon emission computed tomography (SPECT). Coronary angiography revealed a 99% stenosis at the proximal site of the left descending coronary artery and bilateral coronary-to-pulmonary artery fistulae with a saccular aneurysm. Percutaneous transluminal coronary angioplasty abolished chest pain and electrocardiographic changes. However, definitely improved, but still present, stress-induced perfusion abnormalities were demonstrated by an exercise-stress thallium-201 SPECT study. Myocardial ischemia was the only serious complication related to the coronary fistulae, and after they were surgically resected, the reversible perfusion abnormality was no longer observed. These findings suggest that coronary-to-pulmonary artery fistulae potentiated the myocardial ischemia in patient with coronary stenosis leading to unstable angina and prolonged the presence of coronary perfusion abnormality on stress thallium scans probably through a coronary steal phenomenon.