Rapid growth of organic aerosol nanoparticles over a wide tropospheric temperature range.

Nucleation and growth of aerosol particles from atmospheric vapors constitutes a major source of global cloud condensation nuclei (CCN). The fraction of newly formed particles that reaches CCN sizes is highly sensitive to particle growth rates, especially for particle sizes <10 nm, where coagulation losses to larger aerosol particles are greatest. Recent results show that some oxidation products from biogenic volatile organic compounds are major contributors to particle formation and initial growth. However, whether oxidized organics contribute to particle growth over the broad span of tropospheric temperatures remains an open question, and quantitative mass balance for organic growth has yet to be demonstrated at any temperature. Here, in experiments performed under atmospheric conditions in the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN), we show that rapid growth of organic particles occurs over the range from [Formula: see text]C to [Formula: see text]C. The lower extent of autoxidation at reduced temperatures is compensated by the decreased volatility of all oxidized molecules. This is confirmed by particle-phase composition measurements, showing enhanced uptake of relatively less oxygenated products at cold temperatures. We can reproduce the measured growth rates using an aerosol growth model based entirely on the experimentally measured gas-phase spectra of oxidized organic molecules obtained from two complementary mass spectrometers. We show that the growth rates are sensitive to particle curvature, explaining widespread atmospheric observations that particle growth rates increase in the single-digit-nanometer size range. Our results demonstrate that organic vapors can contribute to particle growth over a wide range of tropospheric temperatures from molecular cluster sizes onward.

Impact of immunosuppressive and antifungal drugs on PBMC- and whole blood-based flow cytometric CD154+ Aspergillus fumigatus specific T-cell quantification.

Flow cytometric quantification of CD154+ mould specific T-cells in antigen-stimulated peripheral blood mononuclear cells (PBMCs) or whole blood has been described as a supportive biomarker to diagnose invasive mould infections and to monitor therapeutic outcomes. As patients at risk frequently receive immunosuppressive and antifungal medication, this study compared the matrix-dependent impact of representative drugs on CD154+ T-cell detection rates. PBMCs and whole blood samples from healthy adults were pre-treated with therapeutic concentrations of liposomal amphotericin B, voriconazole, posaconazole, cyclosporine A (CsA) or prednisolone. Samples were then stimulated with an Aspergillus fumigatus lysate or a viral antigen cocktail (CPI) and assessed for CD154+ T-helper cell frequencies. Specific T-cell detection rates and technical assay properties remained largely unaffected by exposure of both matrices to the studied antifungals. By contrast, CsA and prednisolone pre-treatment of isolated PBMCs and whole blood adversely impacted specific T-cell detection rates and caused elevated inter-replicate variation. Unexpectedly, the whole blood-based protocol that uses additional α-CD49d co-stimulation was less susceptible to CsA and prednisolone despite prolonged drug exposure in the test tube. Accordingly, addition of α-CD49d during PBMC stimulation partially attenuated the impact of immunosuppressive drugs on test performance. Translating these results into the clinical setting, false-negative results of CD154+ antigen-specific T-cell quantification need to be considered in patients receiving T-cell-active immunosuppressive medication. Optimized co-stimulation regimes with α-CD49d could contribute to an improved feasibility of functional T-cell assays in immunocompromised patient populations.

Development and evaluation of a whole blood-based approach for flow cytometric quantification of CD154+ mould-reactive T cells.

CD154+ mould-reactive T cells were proposed as a novel biomarker in the diagnosis of invasive mycoses. As PBMC-based protocols for flow cytometric quantification of these cells are logistically challenging and susceptible to preanalytic delays, this study evaluated and optimized a whole blood-based method for the detection of mould-reactive T cells. Blood collection tubes containing costimulatory antibodies and Aspergillus fumigatus mycelial lysates were inoculated with heparinized whole blood from healthy adults, and detection rates of CD154+/CD4+A. fumigatus reactive T cells were compared with PBMC-based detection using samples from the same donors. In contrast to the PBMC-based method, double costimulation with αCD28 and αCD49d was crucial for reliable whole blood stimulation. Optimizing stimulation schemes for both matrixes, significantly higher specific T-cell detection rates were achieved by the whole blood-based method, whereas the unspecific background stimulation remained low. MHC II-dependent CD154+ upregulation was demonstrated for both matrixes. Excellent correlation and reproducible conversion factors between whole blood and PBMC-based results were observed. Using frozen ready-to-use test tubes containing costimulatory antibodies and lysates, detection rates of specific T cells were comparable to freshly prepared blood collection tubes. The optimized whole blood-based protocol was also used to detect Rhizopus arrhizus and Rhizomucor pusillus reactive T cells, resulting in 1.5- to 2.7-fold higher detection rates compared with PBMC-based measurement. In summary, the whole blood protocol is a robust, highly sensitive, and cost-effective method for mould-reactive T-cell quantification, allowing for point-of-care sample stimulation and contributing to better assay standardization in multi-centre evaluation of mould reactive T-cell quantification.

Evaluation of Aspergillus and Mucorales specific T-cells and peripheral blood mononuclear cell cytokine signatures as biomarkers of environmental mold exposure.

Mold specific T-cells have been described as a supportive biomarker to monitor invasive mycoses and mold exposure. This study comparatively evaluated frequencies and cytokine profiles of Aspergillus fumigatus and Mucorales reactive T-cells depending on environmental mold exposure. Peripheral blood mononuclear cells (PBMCs) obtained from 35 healthy donors were stimulated with mycelial lysates of A. fumigatus and three human pathogenic Mucorales species. CD154+ specific T-cells were quantified by flow cytometry. In a second cohort of 20 additional donors, flow cytometry was complemented by 13-plex cytokine assays. Mold exposure of the subjects was determined using a previously established questionnaire. Highly exposed subjects exhibited significantly greater CD154+A. fumigatus and Mucorales specific naïve and memory T-helper cell frequencies. Significant correlation (r = 0.48 - 0.79) was found between A. fumigatus and Mucorales specific T-cell numbers. Logistic regression analyses revealed that combined analysis of mold specific T-cell frequencies and selected cytokine markers (A. fumigatus: IL-5 and TNF-α, R. arrhizus: IL-17A and IL-13) significantly improves classification performance, resulting in 75-90 % predictive power using 10-fold cross-validation. In conclusion, mold specific T-cell frequencies and their cytokine signatures offer promising potential in the assessment of environmental mold exposure. The cytokines identified in this pilot study should be validated in the clinical setting, e. g. in patients with hypersensitivity pneumonitis.

Intra- and inter-individual variability of Aspergillus fumigatus reactive T-cell frequencies in healthy volunteers in dependency of mould exposure in residential and working environment.

Invasive aspergillosis remains a deadly disease in immunocompromised patients, whereas the combination of an exaggerated immune response and continuous exposure lead to various hyperinflammatory diseases. This pilot study aimed to gain an overview of the intra- and inter-individual variability in Aspergillus fumigatus reactive T-helper cells in healthy adults and the correlation with environmental mould exposure. In this flow cytometric study, the frequencies of CD154+ A. fumigatus reactive T cells were evaluated in 70 healthy volunteers. All subjects completed a standardised questionnaire addressing their mould exposure. Subjects with intensive mould exposure in their professional or residential surrounding demonstrated considerably higher mean frequencies of A. fumigatus reactive T-helper and T-memory cells. Comparative evaluation of multiple measurements over time demonstrated relatively conserved reactive T-cell frequencies in the absence of major changes to the exposure profile, whereas those frequently exposed in professional environment or with changes to their risk score demonstrated a marked dependency of antigen reactive T-cell frequencies on recent mould exposure. This pilot study was the first to provide data on the intra-individual variability in A. fumigatus reactive T-cell frequencies and its linkage to mould encounter. Fungus reactive T cells are to be considered a valued tool for the assessment of environmental mould exposure.

Multicomponent new particle formation from sulfuric acid, ammonia, and biogenic vapors.

A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NO x ) and sulfur oxides (SO x ) from fossil fuel combustion, as well as ammonia (NH3) from livestock and fertilizers. Here, we show how NO x suppresses particle formation, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.

Fate of 1,4-dioxane in the aquatic environment: from sewage to drinking water.

Potential health effects of 1,4-dioxane and the limited data on its occurrence in the water cycle command for more research. In the current study, mobility and persistence of 1,4-dioxane in the sewage-, surface-, and drinking water was investigated. The occurrence of 1,4-dioxane was determined in wastewater samples from four domestic sewage treatment plants (STP). The influent and effluent samples were collected during weekly campaigns. The average influent concentrations in all four plants ranged from 262 ± 32 ng L(-1) to 834 ± 480 ng L(-1), whereas the average effluent concentrations were between 267 ± 35 ng L(-1) and 62,260 ± 36,000 ng L(-1). No removal of 1,4-dioxane during water treatment was observed. Owing to its strong internal chemical bonding, 1,4-dioxane is considered non-biodegradable under conventional bio-treatment technologies. The source of increased 1,4-dioxane concentrations in the effluents was identified to originate from impurities in the methanol used in the postanoxic denitrification process in one of the STPs. In view of poor biodegradation in STPs, surface water samples were collected to establish an extent of 1,4-dioxane pollution. Spatial and temporal distribution of 1,4-dioxane in the Rivers Main, Rhine, and Oder was examined. Concentrations reaching 2200 ng L(-1) in the Oder River, and 860 ng L(-1) in both Main and Rhine River were detected. The average monthly load of 1,4-dioxane in the Rhine River was calculated to equal to 172 kg d(-1). In all rivers, concentration of 1,4-dioxane increased with distance from the spring and was found to negatively correlate with the discharge of the river. Additionally, bank filtration and drinking water samples from two drinking water facilities were analyzed for the presence of 1,4-dioxane. The raw water contained 650 ng L(-1)-670 ng L(-1) of 1,4-dioxane, whereas the concentration in the drinking water fell only to 600 ng L(-1) and 490 ng L(-1), respectively. Neither of the purification processes employed was able to reduce the presence of 1,4-dioxane below the precautionary guideline limit of 100 ng L(-1) set by the German Federal Environmental Agency.