One of the challenges of intracorporeal ureterolithotripsy is undesired stone migration. Stone-trapping devices have been designed to prevent this quite common phenomenon. These devices have to be ...effective in terms of ureteral obstruction and safe in terms of resistance to the action of commonly used lithotriptors. This work was conducted to evaluate the efficacy and safety of the recently approved Accordion stone-trapping device in vitro. In a rigid, submerged ureteral model with two different diameters (8 and 10 mm), artificial stones were positioned in direct contact with the engaged Accordion device. A defined number of pneumatic pulses of the LithoClast master at different performance levels was applied and the migration distance of the stone was measured after each single pulse. As a control, the same series was repeated without the stone-trapping device. Secondly, the Accordion device was exposed to a previously defined number of pneumatic or Ho:YAG-laser pulses, in direct contact with the lithotripsy probe, up to a total activation time of 2 min. At different time points, the device was controlled for damage and functionality. The mean stone migration distance without the Accordion device was between 39.2 and 52.8 mm and between 37.8 and 75.4 mm in the 8 and 10 mm tubes, respectively. In comparison, the stone or fragment travelling distance with the device was in the 0-2 mm range. This difference was highly significant. Both pneumatic and laser lithotriptor did not affect the functionality of the Accordion device. The Ho:YAG laser causes small perforations of the film without affecting the devices' stability. The Accordion device appears to be highly efficient and safe in vitro. Clinical trials will have to assess its value in endourological practice. Randomised comparative trials comparing different stone-trapping devices are needed.
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To examine the prevalence of glaucomatous optic neuropathy (GON) in a medium myopic to highly myopic group of patients and its association with parapapillary gamma zone and parapapillary delta zone.
...The retrospective observational hospital-based study included patients who had attended the Tokyo High Myopia Clinics within January 2012 and December 2012 and for whom fundus photographs were available. GON was defined based on the appearance of the optic nerve head on the fundus photographs.
The study included 519 eyes (262 individuals) with a mean age of 62.0±14.3 years (range:13-89 years) and mean axial length of 29.5±2.2 mm (range:23.2-35.3mm). GON was present in 141 (27.2%; 95% confidence intervals (CI): 23.3, 31.0%) eyes. Prevalence of GON increased from 12.2% (1.7, 22.7) in eyes with an axial length of <26.5mm to 28.5% (24.4, 32.5) in eyes with an axial length of ≥26.5mm, to 32.6% (27.9, 37.2) in eyes with an axial length of ≥28mm, to 36.0% (30.5, 41.4) in eyes with an axial length of ≥29mm, and GON prevalence increased to 42.1% (35.5, 48.8) in eyes with an axial length of ≥30mm. In multivariate analysis, higher GON prevalence was associated (Nagelkerke r2: 0.28) with larger parapapillary delta zone diameter (P<0.001; odds ratio (OR):1.86;95%CI:1.33,2.61), longer axial length (P<0.001;OR:1.45;95%CI:1.26,1.67) and older age (P = 0.01;OR:1.03;95%CI:1.01,1.05). If parapapillary delta zone width was replaced by the vertical disc diameter, higher GON prevalence was associated (r2:0.24) with larger vertical optic disc diameter (P = 0.04;OR:1.70;95%CI:1.03,2.81), after adjusting for longer axial length (P<0.001;OR:1.44;95%CI:1.26,1.64) and older age (P<0.001;OR:1.04;95%CI:1.02,1.06).
Axial elongation associated increase in GON prevalence (mean: 28.1% in a medium to highly myopic study population) was associated with parapapillary delta zone as surrogate for an elongated peripapillary scleral flange and with larger optic disc size.
Particle pH is a critical but poorly constrained quantity that affects many aerosol processes and properties, including aerosol composition, concentrations, and toxicity. We assess PM1 pH as a ...function of geographical location and altitude, focusing on the northeastern U.S., based on aircraft measurements from the Wintertime Investigation of Transport, Emissions, and Reactivity campaign (1 February to 15 March 2015). Particle pH and water were predicted with the ISORROPIA‐II thermodynamic model and validated by comparing predicted to observed partitioning of inorganic nitrate between the gas and particle phases. Good agreement was found for relative humidity (RH) above 40%; at lower RH observed particle nitrate was higher than predicted, possibly due to organic‐inorganic phase separations or nitrate measurement uncertainties associated with low concentrations (nitrate < 1 µg m−3). Including refractory ions in the pH calculations did not improve model predictions, suggesting they were externally mixed with PM1 sulfate, nitrate, and ammonium. Sample line volatilization artifacts were found to be minimal. Overall, particle pH for altitudes up to 5000 m ranged between −0.51 and 1.9 (10th and 90th percentiles) with a study mean of 0.77 ± 0.96, similar to those reported for the southeastern U.S. and eastern Mediterranean. This expansive aircraft data set is used to investigate causes in variability in pH and pH‐dependent aerosol components, such as PM1 nitrate, over a wide range of temperatures (−21 to 19°C), RH (20 to 95%), inorganic gas, and particle concentrations and also provides further evidence that particles with low pH are ubiquitous.
Key Points
Highly acidic aerosols (pH = 0.77 ± 0.96) for altitudes up to 5000 m in the northeastern U.S. in wintertime
Thermodynamically predicted HNO3−NO3− partitioning by ISORROPIA‐II agrees with observation above 40% RH
Particle pH should be explicitly determined to accurately assess properties impacted by aerosol acidity, such as HNO3−NO3− partitioning
Evolution of brown carbon in wildfire plumes Forrister, Haviland; Liu, Jiumeng; Scheuer, Eric ...
Geophysical research letters,
16 June 2015, Letnik:
42, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Particulate brown carbon (BrC) in the atmosphere absorbs light at subvisible wavelengths and has poorly constrained but potentially large climate forcing impacts. BrC from biomass burning has ...virtually unknown lifecycle and atmospheric stability. Here, BrC emitted from intense wildfires was measured in plumes transported over 2 days from two main fires, during the 2013 NASA SEAC4RS mission. Concurrent measurements of organic aerosol (OA) and black carbon (BC) mass concentration, BC coating thickness, absorption Ångström exponent, and OA oxidation state reveal that the initial BrC emitted from the fires was largely unstable. Using back trajectories to estimate the transport time indicates that BrC aerosol light absorption decayed in the plumes with a half‐life of 9 to 15 h, measured over day and night. Although most BrC was lost within a day, possibly through chemical loss and/or evaporation, the remaining persistent fraction likely determines the background BrC levels most relevant for climate forcing.
Key Points
Biomass burning brown carbon has unknown lifecycle and atmospheric stability
Brown carbon and aerosol properties from two fires are measured for 50 h
Wildfire brown carbon lifetime was 9–15 h, but a small fraction is stable
Anthropogenic air pollutants such as nitrogen oxides (NO(x) = NO + NO(2)), sulfur dioxide (SO(2)), and volatile organic compounds (VOC), among others, are emitted to the atmosphere throughout the ...year from energy production and use, transportation, and agriculture. These primary pollutants lead to the formation of secondary pollutants such as fine particulate matter (PM(2.5)) and ozone (O(3)) and perturbations to the abundance and lifetimes of short-lived greenhouse gases. Free radical oxidation reactions driven by solar radiation govern the atmospheric lifetimes and transformations of most primary pollutants and thus their spatial distributions. During winter in the mid and high latitudes, where a large fraction of atmospheric pollutants are emitted globally, such photochemical oxidation is significantly slower. Using observations from a highly instrumented aircraft, we show that multi-phase reactions between gas-phase NO(x) reservoirs and aerosol particles, as well as VOC emissions from anthropogenic activities, lead to a suite of atypical radical precursors dominating the oxidizing capacity in polluted winter air, and thus, the distribution and fate of primary pollutants on a regional to global scale.
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