VOC emission rates over London and South East England obtained by airborne eddy covariance.

Volatile organic compounds (VOCs) originate from a variety of sources, and play an intrinsic role in influencing air quality. Some VOCs, including benzene, are carcinogens and so directly affect human health, while others, such as isoprene, are very reactive in the atmosphere and play an important role in the formation of secondary pollutants such as ozone and particles. Here we report spatially-resolved measurements of the surface-to-atmosphere fluxes of VOCs across London and SE England made in 2013 and 2014. High-frequency 3-D wind velocities and VOC volume mixing ratios (made by proton transfer reaction - mass spectrometry) were obtained from a low-flying aircraft and used to calculate fluxes using the technique of eddy covariance. A footprint model was then used to quantify the flux contribution from the ground surface at spatial resolution of 100 m, averaged to 1 km. Measured fluxes of benzene over Greater London showed positive agreement with the UK's National Atmospheric Emissions Inventory, with the highest fluxes originating from central London. Comparison of MTBE and toluene fluxes suggest that petroleum evaporation is an important emission source of toluene in central London. Outside London, increased isoprene emissions were observed over wooded areas, at rates greater than those predicted by a UK regional application of the European Monitoring and Evaluation Programme model (EMEP4UK). This work demonstrates the applicability of the airborne eddy covariance method to the determination of anthropogenic and biogenic VOC fluxes and the possibility of validating emission inventories through measurements.

Effects of land use on surface-atmosphere exchanges of trace gases and energy in Borneo: comparing fluxes over oil palm plantations and a rainforest.

This paper reports measurements of land-atmosphere fluxes of sensible and latent heat, momentum, CO(2), volatile organic compounds (VOCs), NO, NO(2), N(2)O and O(3) over a 30 m high rainforest canopy and a 12 m high oil palm plantation in the same region of Sabah in Borneo between April and July 2008. The daytime maximum CO(2) flux to the two canopies differs by approximately a factor of 2, 1200 mg C m(-2) h(-1) for the oil palm and 700 mg C m(-2) h(-1) for the rainforest, with the oil palm plantation showing a substantially greater quantum efficiency. Total VOC emissions are also larger over the oil palm than over the rainforest by a factor of 3. Emissions of isoprene from the oil palm canopy represented 80 per cent of the VOC emissions and exceeded those over the rainforest in similar light and temperature conditions by on average a factor of 5. Substantial emissions of estragole (1-allyl-4-methoxybenzene) from the oil palm plantation were detected and no trace of this VOC was detected in or above the rainforest. Deposition velocities for O(3) to the rainforest were a factor of 2 larger than over oil palm. Emissions of nitrous oxide were larger from the soils of the oil palm plantation than from the soils of the rainforest by approximately 25 per cent. It is clear from the measurements that the large change in the species composition generated by replacing rainforest with oil palm leads to profound changes in the net exchange of most of the trace gases measured, and thus on the chemical composition of the boundary layer over these surfaces.

Endovenous laser ablation of the small saphenous vein sparing the saphenopopliteal junction.

To assess outcomes after endovenous laser ablation (EVLA) of the small saphenous vein (SSV). Retrospective review was performed of all consecutive EVLA procedures performed over a 39-month period at three neighboring vein practices for symptomatic, duplex ultrasound-proven incompetence of the SSV. EVLA was performed under ultrasound guidance with an 810- or 980-nm diode laser in continuous mode using the pullback method while sparing the deep, most cephalad segment of the SSV near the saphenopopliteal junction. Follow-up after EVLA included patient symptoms, physical examination, and duplex ultrasound. Pretreatment variables were similar across all three practices. EVLA was performed to treat 67 incompetent SSVs in 63 patients (86% women; mean age and 95% confidence interval, 50 +/- 3 years; range, 20-82 years). Average energy delivered was 92 J/cm. Immediate technical success and occlusion of the treated vein at 1-2 weeks was 100%. Imaging follow-up length was 243 +/- 65 days (range, 3-893 days). Clinical follow-up (243 +/- 66 days) showed symptomatic improvement in 66 (99%) of 67 patients; one patient had recanalization with recurrent reflux by ultrasound (2%). Complications included one case of paresthesias lasting beyond 1 month of follow-up (2%) and three cases of superficial phlebitis (4%), but no deep vein thrombosis, skin burns, or other complications. Although ablation involved only the superficial portion of the SSV and spared its deep segment in the popliteal fossa, SSV occlusion typically extended up to the saphenopopliteal junction or to a gastrocnemial collateral, without popliteal vein involvement. EVLA of the SSV is safe and effective when the saphenopopliteal junction and popliteal fossa are avoided. This approach may help reduce the risk of paresthesias or other complications while maintaining low recanalization rates.

Solubility of toluene, benzene and TCE in high-microbial concentration systems.

We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g mL(-1) for TCE and 0.25 g mL(-1) for benzene and toluene. The solubility limit increased from 21 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20mM. For TCE, the solubility increased from 8mM to more than 1000 mM. Solubility for TCE (trichloroethylene) was most heavily impacted by biomass levels, changing by two orders of magnitude as the microbial concentrations approach those in biofilms.

Impact of quality management monitoring and intervention on central venous catheter dysfunction in the outpatient chemotherapy infusion setting.

PURPOSE: To assess the utility of maintaining and analyzing a quality-management database while investigating a subjectively perceived increase in the incidence of tunneled catheter and port dysfunction in a cohort of oncology outpatients. MATERIALS AND METHODS: All 152 patients undergoing lytic therapy (2-4 mg alteplase) of a malfunctioning indwelling central venous catheter (CVC) from January through June 2004 at a single cancer center in the United States were included in a quality-management database. Patients were categorized by time to device failure and the initial method of catheter placement (surgery vs interventional radiology). Data were analyzed after 3 months, and areas of possible improvement were identified and acted upon. Three months of follow-up data were then collected and similarly analyzed. RESULTS: In a 6-month period, 152 patients treated for catheter malfunction received a total of 276 doses of lytic therapy. A 3-month interim analysis revealed a disproportionately high rate (34%) of early catheter malfunction (ECM; <30 days from placement). Postplacement radiographs demonstrated suboptimal catheter positioning in 67% of these patients, all of whom had surgical catheter placement. There was a 50% absolute decrease in the number of patients presenting with catheter malfunction in the period from April through June (P < .001). Evaluation of postplacement radiographs in these patients demonstrated a 50% decrease in the incidence of suboptimal positioning (P < .05). CONCLUSIONS: Suboptimal positioning was likely responsible for some, but not all, cases of ECM. Maintenance of a quality-management database is a relatively simple intervention that can have a clear and important impact on the quality and cost of patient care.

Decabromodiphenyl ether (deca-BDE) commercial mixture components, and other PBDEs, in airborne particles at a UK site.

The occurrence of the major components of the decabromodiphenyl ether (deca-BDE) flame retardant and other PBDEs was investigated in daily air particulate samples from 17th April to 20th May 2004 at a semi-rural site in north-west England. BDE-209 was found at between <0.49 and 100 pg m(-3) (median 13 pg m(-3)), and other higher-brominated PBDE congeners were also found, particularly the nona-BDEs (e.g. BDE-207: <0.042-79 pg m(-3), median 2.5 pg m(-3)). Deca- and nona-BDEs dominated the median particulate sample congener profile: 60% BDE-209, 16% BDE-207, 6% BDE-208 and 4% BDE-206. Nona-BDEs were greatly enriched, relative to BDE-209, compared to the deca-BDE commercial mixture, which may suggest degradation of BDE-209 between source and sampling site, or release from older deca-BDE commercial mixtures, which may have contained higher proportions of nona-BDEs. The highest PBDE concentrations occurred when air-masses passed over urban and industrial areas to the SSW-SW, though small local influences may also be seen. PBDE concentrations appear to have been influenced mainly by particle levels: 1-3 microm diameter particles for BDE-153, and 3-10 microm particles for BDEs with 7-10 Br atoms. BDE-153 may either be released from combustion sources, or re-condense onto small particles after emission, whereas BDE-209 and nona-BDEs appear to be associated with larger dust particles from industrial or domestic sources.

Descending tumor thrombus from renal cell carcinoma metastases with SVC syndrome.

We describe a case of renal cell carcinoma metastases to the thyroid gland invading local veins and extending to the neck veins causing superior vena cava (SVC) syndrome.

Percutaneous treatment of high-output chylothorax with embolization or needle disruption technique.

Surgical ligation of the thoracic duct is associated with a high degree of morbidity; therefore, a minimally invasive approach is desirable. Herein, eight percutaneously treated patients are described. In four patients, the thoracic duct was embolized with use of coils and glue. In the other four patients, lymphatic ducts were disrupted by multiple needle punctures. The median chest tube drainage substantially decreased in both patient groups from more than 1,300 mL the day before the procedure to less than 300 mL 2 days after the procedure. The median times to chest tube removal were 7 days in the embolization group and 3.5 days in the needle disruption group.

A simplified method to create quantitative, "fixed" uranyl-contaminated metal coupons.

A method was developed and validated to quantitatively apply and "fix" uranyl contamination onto a metal surface (steel). Simple approaches are needed to create test surfaces in order to quantify contaminant removal or "decon" methods. We used steel discs sized to allow direct and accurate alpha counting in a Ludlum scanner from radioactive contaminants. A typical 3.8-cm-diameter coupon had a depleted uranyl loading of about 0.1 mg U cm with a count of 980 dpm. The resulting alpha radiation was measured with a precision of >97% for the same coupon. The alpha concentration on replicate coupons differed by as much as 9% (standard deviation). This method, based on earlier methods, required a uranyl solution to be dried but lowers the baking temperature to less than 100 degrees C to increase safety in a typical radiological laboratory. A dike was used to provide a uniform coating of the uranyl solution.

Varus collapse of comminuted distal femur fractures after open reduction and internal fixation with a lateral condylar buttress plate.

Twenty-six comminuted distal femur fractures treated with a lateral condylar buttress plate were followed up until fracture union or implant revision (mean follow-up, 26 months). Mean postoperative angle (medial distal femoral angle immediately after surgery) was 96 degrees, and mean final angle (angle at fracture healing or implant revision) was 91 degrees (P = .06). Distal femoral angle decreased 5 degrees or less in 15 patients, 6 degrees to 10 degrees in 8 patients, and more than 10 degrees in 3 patients. Final distal femoral angle was 90 degrees or less in 13 of the 26 fractures: 38% of these 13 fractures required reconstruction for nonunion, malunion, or knee arthrosis. The lateral condylar buttress plate, which is not a fixed-angle device, allowed more than 5 degrees of varus collapse to occur in 42% of the comminuted distal femur fractures.