The ground penetration radar (GPR) can be used for soil water content measurements. To prove the accuracy of the GPR, measurements were carried out on four lysimeters (surface 1m2, depth 1.5m) during ...one vegetation period. The lysimeters were planted with lucerne and filled with three different soils: a loamy sand, a sandy loam and a silt loam. The ground water tables were at 1.35 and 2.1m. The lysimeters were weighed, so that it was possible to calculate the changes in water content with very high accuracy. For the GPR-measurements a 1GHz-antenna was used. Only in the sandy loam reflected signal from the bottom of the lysimeter could be obtained. The standard deviation between the GPR and the lysimeter data was 0.01m3/m3 using all data and 0.0026m3/m3 using only measurements in the wetter range. For this material an experimental calibration curve between the soil water content (θ) and the relative dielectric constant (ε) was calculated by comparing GPR-results with lysimeter data. The data results in a linear function θ(ε) for the measured range of water contents. Compared to published calibration curves used for TDR-technique, the Topp-function gives the best results.
We investigated smoke emissions from fires in savanna, forest, and agricultural ecosystems by airborne sampling of plumes close to prescribed burns and incidental fires in southern Africa. Aerosol ...samples were collected on glass fiber filters and on stacked filter units, consisting of a Nuclepore prefilter for particles larger than ∼1–2 μm and a Teflon second filter stage for the submicron fraction. The samples were analyzed for soluble ionic components, organic carbon, and black carbon. Onboard the research aircraft, particle number and volume distributions as a function of size were determined with a laser‐optical particle counter and the black carbon content of the aerosol with an aethalometer. We determined the emission ratios (relative to CO2 and CO) and emission factors (relative to the amount of biomass burnt) for the various aerosol constituents. The smoke aerosols were rich in organic and black carbon, the latter representing 10–30% of the aerosol mass. K+ and NH4+ were the dominant cationic species in the smoke of most fires, while Cl− and SO42− were the most important anions. The aerosols were unusually rich in Cl−, probably due to the high Cl content of the semiarid vegetation. Comparison of the element budget of the fuel before and after the fires shows that the fraction of the elements released during combustion is highly variable between elements. In the case of the halogen elements, almost the entire amount released during the fire is present in the aerosol phase, while in the case of C, N, and S, only a small proportion ends up as particulate matter. This suggests that the latter elements are present predominantly as gaseous species in the fresh fire plumes studied here.
CO, CH4, and organic trace gases were measured in air samples collected during several flights with a DC‐3 aircraft through the plumes from savanna fires and agricultural fires during the SAFARI 92 ...campaign in southern Africa in September and October 1992. In all samples a variety of higher molecular weight organic compounds was found, most of which are very reactive. More than 70 of the roughly 140 major components present could be identified. Typically, mixing ratios of several hundred parts per billion carbon of organic compounds were measured inside the plumes, corresponding to an emission ratio of total organic carbon relative to CO2 of up to 1%. About 50% of these emissions were in the form of oxygenated and unsaturated compounds. The contributions of still unknown compounds to the total emission of organic compounds add up to another 20–30%. The observed emission ratios relative to CO2 show a considerable variation depending on the fuel type and the burning stages of the fire. The lowest value of the emission ratio of the sum of all identified organic compounds relative to CO2 was found for a sugar cane fire with (1.7±0.7)×10−3 (ppb C/ppb CO2). For a large savanna fire in Kruger National Park the ratio was (7.4±1.6)×10−3 (ppb C/ppb CO2). The highest value was (13.7±0.9)×10−3 (ppb C/ppb CO2) for an uncontrolled fire of mainly wood and shrub in the Drakensberg region. Results of model calculations show that in biomass‐burning plumes, reactive organic compounds contribute significantly to the formation of ozone, especially during the initial phase of photochemical processing.
As part of the Oxidizing Capacity of the Tropospheric Atmosphere (OCTA) project, an intensive measurement campaign was conducted in July/August 1993 at the high‐altitude observatory Izaña, Tenerife. ...Measurements of NO, NO2, NOy, PAN, JNO2, CO, VOC, HCHO, H2O2, O3, and ROx were made to study the photochemical processes which control the oxidizing capacity of the remote troposphere. Special attention was paid to the processes controlling the budget of ozone. Diurnal changes in the concentration of the species resulted primarily from the transition between downslope flow (usually free tropospheric air) and upslope flow (a mixture of marine boundary layer air and free tropospheric air modified by island emissions). Median concentrations for downslope and upslope conditions were NOx (47/76 parts per trillion by volume (pptv)), NOy (392/519 pptv), peroxyacetylnitrate (PAN) (10/23 pptv), CO (89/92 parts per billion by volume (ppbv), ethane (499/486 pptv), propane (35/40 pptv), ethene (25/31 pptv), isoprene (0/60 pptv), HCHO (1.1/1.4 ppbv), H2O2 (2.4/2.1 ppbv), and O3 (40/38 ppbv). Maximum amounts of ROx were measured around noon and reached values up to 70 pptv with no observable signal in the night during downslope conditions.
Simultaneous in situ measurements of NOy, HNO3, O3, N2O, and CO have been performed in the lower stratosphere during the Stratosphere‐Troposphere Experiment by Aircraft Measurements (STREAM) II ...intensive winter campaign in February 1995 from Kiruna airport (northern Sweden) with a Cessna Citation II twinjet aircraft up to a maximum altitude of 12.8 km. The flights were coordinated with the Arctic Second European Stratospheric Arctic and Midlatitude Experiment (SESAME) winter campaign. Strongly elevated levels of total reactive nitrogen (NOy) and its most abundant contributing species, nitric acid (HNO3), with mixing ratios up to 9 parts per billion by volume (ppbv), were observed during all flights at altitudes near 12 km. On average, the measured NOy concentrations exceed the expected levels by a factor of 2–3. Normal background NOy has been calculated from observed N2O mixing ratios using the NOy‐N2O correlation reported for the undisturbed northern hemisphere. This indicates that subsidence of air in the vortex alone cannot explain these findings. We propose that the elevated NOy concentrations were caused by nitrification of the lower stratosphere associated with sedimentation and evaporation of polar stratospheric cloud particles that carry down HNO3 from higher altitudes, that is, from altitudes up to about 25 km.
The recently disclosed next generation of reversible, selective, and potent MetAP-2 inhibitors introduced a cyclic tartronic diamide scaffold. However, the lead compound 1a suffered from ...enterohepatic circulation, preventing further development. Nevertheless, 1a served as a starting point for further optimization. Maintaining potent antiproliferation activity, while improving other compound properties, enabled the generation of an attractive array of new MetAP-2 inhibitors. The most promising derivatives were identified by a multiparameter analysis of the compound properties. Essential for the efficient selection of candidates with in vivo activity was the identification of molecules with a long residence time on the target protein, high permeability, and low efflux ratio not only in Caco-2 but also in the MDR-MDCK cell line. Orally bioavailable, potent, and reversible MetAP-2 inhibitors impede the growth of primary endothelial cells and demonstrated antitumoral activity in mouse models. This assessment led to the nomination of the clinical development compound M8891, which is currently in phase I clinical testing in oncology patients.
Zenker diverticulum (ZD), a pulsion diverticulum of the esophagus, has been traditionally managed with an open surgical approach, but endoscopic transoral stapling has been reported with increasing ...frequency. The objective of this study was to evaluate the results of endoscopic repair of ZD by a thoracic surgery service.
We conducted a retrospective review of patients who underwent transoral stapling repair of ZD at our institution by the thoracic surgery service. We evaluated perioperative outcomes including dysphagia (1, no dysphagia to 5, unable to swallow saliva) and failure of repair requiring surgical intervention.
A total of 151 patients (median age, 78 years; 75 men, 76 women) underwent evaluation for endoscopic repair of ZD. Endoscopic stapled repair of the ZD was completed in 135. Sixteen patients underwent conversion to open repair. The perioperative mortality was 0.6% (1 patient). The median hospital stay was 2 days (range, 0-18 days). Complications occurred in 5 patients who underwent endoscopic repair. The mean preoperative dysphagia score was 2.8 and improved to 1.2 during follow-up (median, 16 months; P < .001). During further follow-up (median, 52 months), 8 patients (5.3%) had failure of the endoscopic repair requiring open surgery (n = 5) or redo transoral stapling (n = 3).
Endoscopic stapling repair of ZD can be performed safely with good results in experienced centers by thoracic surgeons with significant esophageal experience. Long-term follow-up is required to evaluate the durability of endoscopic repair of ZD.
Transoral stapling of Zenker diverticulum (ZD) by a thoracic surgical service. A total of 151 patients underwent attempted endoscopic transoral repair of ZD. Endoscopic stapled repair of the ZD was completed in 135. The mean preoperative (Pre Op) dysphagia score was 2.8 and improved to 1.2 during follow-up (median, 16 months; P < .001). During further follow-up (median, 52 months), 8 patients (5.3%) had failure of the endoscopic repair requiring open surgery (n = 5) or redo transoral stapling (n = 3). Transoral endoscopic stapling repair of ZD can be performed safely with good results in experienced centers by thoracic surgeons with significant esophageal experience. Post Op, Postoperative. Display omitted
Importance of this Paper: The degradation of isoprene under the effect of photochemistry, leads to the formation of carbonyl compounds: mainly formaldehyde, methyl vinyl ketone and methacrolein. The ...relative abundance of these species depends on the oxidation processes and mainly on the oxidants involved in their production, leading to significant diurnal variations. These yields of formation have been studied from `in situ' measurements during the FIELDVOC'94 campaign in a eucalyptus forest of Portugal.
During FIELDVOC'94, isoprene and its main degradation products, methyl vinyl ketone (MVK), methacrolein (MAC) and formaldehyde (HCHO) were measured in a Portuguese eucalyptus forest. All compounds were analyzed by two or three different techniques. Isoprene mixing ratios were highest on sunny days (8 to 12 ppbv) correlating with temperature, and lowest at night (<0.02 ppbv). MVK and MAC reached on daytime ∼1 and ∼0.5 ppbv, respectively, and minimum values at night, for both species, comprised between 0.1 and 0.2 ppbv. Formaldehyde varied between 1 ppbv (night) and 9 ppbv (sunny day). Ambient mixing ratios of all compounds were highly variable due to changeable meteorological conditions. The MVK/MAC ratio between 1.5 and 2.5 is indicative of OH-oxidation as the primary isoprene degradation process during the day.
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