Four Years of Active Sampling and Measurement of Atmospheric Polycyclic Aromatic Hydrocarbons and Oxygenated Polycyclic Aromatic Hydrocarbons in Dronning Maud Land, East Antarctica.

Antarctica, protected by its strong polar vortex and sheer distance from anthropogenic activity, was always thought of as pristine. However, as more data on the occurrence of persistent organic pollutants on Antarctica emerge, the question arises of how fast the long-range atmospheric transport takes place. Therefore, polycyclic aromatic hydrocarbons (PAHs) and oxygenated (oxy-)PAHs were sampled from the atmosphere and measured during 4 austral summers from 2017 to 2021 at the Princess Elisabeth station in East Antarctica. The location is suited for this research as it is isolated from other stations and activities, and the local pollution of the station itself is limited. A high-volume sampler was used to collect the gas and particle phase (PM10) separately. Fifteen PAHs and 12 oxy-PAHs were quantified, and concentrations ranging between 6.34 and 131 pg m3 (Σ15PAHs-excluding naphthalene) and between 18.8 and 114 pg m3 (Σ13oxy-PAHs) were found. Phenanthrene, pyrene, and fluoranthene were the most abundant PAHs. The gas-particle partitioning coefficient log(Kp) was determined for 6 compounds and was found to lie between 0.5 and -2.5. Positive matrix factorization modeling was applied to the data set to determine the contribution of different sources to the observed concentrations. A 6-factor model proved a good fit to the data set and showed strong variations in the contribution of different air masses. During the sampling campaign, a number of volcanic eruptions occurred in the southern hemisphere from which the emission plume was detected. The FLEXPART dispersion model was used to confirm that the recorded signal is indeed influenced by volcanic eruptions. The data was used to derive a transport time of between 11 and 33 days from release to arrival at the measurement site on Antarctica.

Value of magnetic resonance imaging/ultrasound fusion prostate biopsy to select patients for focal therapy.

PURPOSE: To investigate the role of transrectal MRI fusion biopsy to select patients for prostate cancer focal therapy. METHODS: Patients with suspected prostate cancer underwent transrectal MRI fusion biopsy with the Koelis trinity device. Two focal therapy eligibility criteria were subsequently defined: Group 1: PSA ≤ 15 ng/ml, unilateral csPCa, ISUP grade ≤ 2, no contralateral PIRADS 3-5 lesion; Group 2: same criteria but ISUP grade 3. These subgroups were correlated with histopathological post-prostatectomy parameters for stage pT2, unilateral csPCa, no ISUP upgrading. In addition, parameters of csPCa detection were analyzed for patients undergoing primary and re-biopsy. RESULTS: Four hundred fourteen consecutive patients were analyzed (314 for primary biopsy, 100 for re-biopsy). Post-prostatectomy whole mount section analysis was available from 155 patients. 39 and 62 of these patients met focal therapy inclusion criteria for group 1 and group 2, respectively. A correlation with final pathology parameters following radical prostatectomy (stage pT2, unilateral csPCa, no ISUP upgrading) revealed a positive predictive value of only 53.8% and 64.5% for Group 1 and 2, respectively. The overall csPCa detection rate was 73.7%. In the re-biopsy group 20% additional patients with csPCa were detected by targeted biopsy. CONCLUSION: Despite high csPCa detection rates following MRI fusion biopsy our study demonstrated that, using final pathology to confirm locally advanced tumor stage, presence of bilateral csPCa and ISUP upgrading, between 35.5 and 46.2% of patients would have been incorrectly selected for focal therapy.

Atmospheric phase distribution of oxidized and reduced nitrogen at a forest ecosystem research site.

Atmospheric concentrations of gaseous NH3 and HNO3 and of particulate NH4+ and NO3- were measured during various seasons at a forest ecosystem research site in the "Fichtelgebirge" mountains in Central Europe. Air masses arriving at this site were highly variable with respect to trace compound concentration levels and their concentration ratios. However, the distributions of NH4+ and NO3- within the aerosol particle size spectra exhibited some very consistent patterns, with the former dominating the fine particle concentrations, and the latter dominating the coarse particles range, respectively. Overall, the particulate phase (NH4+ + NO3-) dominated the atmospheric nitrogen budget (particulate and gas phase, NH4+ + NO3- + NH3 + HNO3) by more than 90% of the median total mixing ratio in winter, and by more than 60% in summer. The phase partitioning varied significantly between the winter and summer seasons, with higher relative importance of the gaseous species during summer, when air temperatures were higher and relative humidities lower as compared to the winter season. Reduced nitrogen dominated over oxidized nitrogen, indicating the prevailing influence of emissions from agricultural activity as compared to traffic emissions at this mountainous site. A model has been successfully applied in order to test the hypothesis of thermodynamic equilibrium between the particulate and gas phases.

Aerosol chamber study of optical constants and N2O5 uptake on supercooled H2SO4/H2O/HNO3 solution droplets at polar stratospheric cloud temperatures.

The mechanism of the formation of supercooled ternary H(2)SO(4)/H(2)O/HNO(3) solution (STS) droplets in the polar winter stratosphere, i.e., the uptake of nitric acid and water onto background sulfate aerosols at T < 195 K, was successfully mimicked during a simulation experiment at the large coolable aerosol chamber AIDA of Forschungszentrum Karlsruhe. Supercooled sulfuric acid droplets, acting as background aerosol, were added to the cooled AIDA vessel at T = 193.6 K, followed by the addition of ozone and nitrogen dioxide. N(2)O(5), the product of the gas phase reaction between O(3) and NO(2), was then hydrolyzed in the liquid phase with an uptake coefficient gamma(N(2)O(5)). From this experiment, a series of FTIR extinction spectra of STS droplets was obtained, covering a broad range of different STS compositions. This infrared spectra sequence was used for a quantitative test of the accuracy of published infrared optical constants for STS aerosols, needed, for example, as input in remote sensing applications. The present findings indicate that the implementation of a mixing rule approach, i.e., calculating the refractive indices of ternary H(2)SO(4)/H(2)O/HNO(3) solution droplets based on accurate reference data sets for the two binary H(2)SO(4)/H(2)O and HNO(3)/H(2)O systems, is justified. Additional model calculations revealed that the uptake coefficient gamma(N(2)O(5)) on STS aerosols strongly decreases with increasing nitrate concentration in the particles, demonstrating that this so-called nitrate effect, already well-established from uptake experiments conducted at room temperature, is also dominant at stratospheric temperatures.