Ozone depletion events observed in the high latitude surface layer during the TOPSE aircraft program

During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58° between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as Baffin Bay and Hudson Bay and as late as 22 May. There is good evidence that these more southern events did not form in situ but were the result of export of ozone-depleted air from the surface layer of the Arctic Ocean. Surprisingly, relatively intact transport of ODEs occurred over distances of 900–2000 km and in some cases over rough terrain. Accumulation of constituents in the frozen surface over the dark winter period cannot be a strong prerequisite of ozone depletion since latitudes south of the Arctic Ocean would also experience a long dark period. Some process unique to the Arctic Ocean surface or its coastal regions remains unidentified for the release of ozone-depleting halogens. There was no correspondence between coarse surface features such as solid ice/snow, open leads, or polynyas with the occurrence of or intensity of ozone depletion over the Arctic or subarctic regions. Depletion events also occurred in the absence of long-range transport of relatively fresh “pollution” within the high latitude surface layer, at least in spring 2000. Direct measurements of halogen radicals were not made. However, the flights do provide detailed information on the vertical structure of the surface layer and, during the constant 30 m altitude legs, measurements of a variety of constituents including hydroxyl and peroxy radicals. A summary of the behavior of these constituents is made. The measurements were consistent with a source of formaldehyde from the snow/ice surface. Median NOx in the surface layer was 15 pptv or less, suggesting that surface emissions were substantially converted to reservoir constituents by 30 m altitude and that ozone production rates were small (0.15–1.5 ppbv/d) at this altitude. Peroxyacetylnitrate (PAN) was by far the major constituent of NOy in the surface layer independent of the ozone mixing ratio

Ozone, aerosol, potential vorticity, and trace gas trends observed at high‐latitudes over North America from February to May 2000

Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty‐eight flights over seven deployments covering the latitudes of 40°–85°N between 4 February and 23 May 2000 as part of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) field experiment. Each deployment started from Broomfield, Colorado, with bases in Churchill, Canada, and on most deployments, Thule Air Base, Greenland. Nadir and zenith lidar O3 measurements were combined with in situ O3 measurements to produce vertically continuous O3 profiles from near the surface to above the tropopause. Potential vorticity (PV) distributions along the flight track were obtained from several different meteorological analyses. Ozone, aerosol, and PV distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. Ozone was found to increase in the middle free troposphere (4–6 km) at high latitudes (60°–85°N) by an average of 4.6 ppbv/mo (parts per billion by volume per month) from about 54 ppbv in early February to over 72 ppbv in mid‐May. The average aerosol scattering ratios at 1064 nm in the same region increased rapidly at an average rate of 0.36/mo from about 0.38 to over 1.7. Ozone and aerosol scattering were highly correlated over the entire field experiment, and PV and beryllium (7Be) showed no significant positive trend over the same period. The primary cause of the observed O3 increase in the mid troposphere at high latitudes was determined to be the photochemical production of O3 in pollution plumes with less than 20% of the increase from stratospherically‐derived O3

Relationship between HER-2 overexpression and brain metastasis in esophageal cancer patients

AIM: To study if HER-2 overexpression by locally advanced esophageal cancers increase the chance of brain metastasis following esophagectomy

Reperfusion Strategies and Outcomes of ST-Segment Elevation Myocardial Infarction Patients in Canada: Observations From the Global Registry of Acute Coronary Events (GRACE) and the Canadian Registry of Acute Coronary Events (CANRACE)

BACKGROUND: We examine the clinical characteristics and outcomes of ST-elevation myocardial infarction (STEMI) patients receiving various reperfusion therapies in 2 contemporary Canadian registries. METHODS: Of 4045 STEMI patients, 2024 received reperfusion therapy and had complete data on invasive management. They were stratified by reperfusion strategy used: primary percutaneous coronary intervention (PCI) (n =716); fibrinolysis with rescue PCI (n =177); fibrinolysis with urgent/elective PCI (n =210); and fibrinolysis without PCI (n =921). Data were collected on clinical and laboratory findings, and outcomes. RESULTS: Compared with fibrinolytic-treated patients, patients treated with primary PCI were younger and had higher Killip class, had longer time to delivery of reperfusion therapy, and utilized more antiplatelet therapy but less heparin, beta-blockers and angiotensin-converting enzyme inhibitors. In-hospital death occurred in 2.7% of patients treated with primary PCI, 1.7% fibrinolysis-rescue PCI, 1.0% fibrinolysis-urgent/elective PCI, and 4.8% fibrinolysis-alone (P =0.009); the rates of death/reinfarction were 3.9%, 4.0%, 4.3%, and 7.1% (P =0.032), respectively. The rate of shock was highest in the primary PCI group. Rates of heart failure or major bleeding were similar in the 4 groups. In multivariable analysis, no PCI during hospitalization was associated with death and reinfarction (adjusted odds ratio = 1.66; 95% confidence interval, 1.03-2.70; P =0.04). CONCLUSIONS: Clinical features, time to reperfusion, and medication utilization differed with respect to the reperfusion strategy. While low rates of re-infarction/death were observed, these complications occurred more frequently in those who did not undergo PCI during index hospitalization. Inc. All rights reserved