Extending fundamental knowledge on aerosol formation bymeasuring sub–3 nm ions and particles

This thesis focuses on the experimental characterization of secondary atmospheric nanoparticles and ions during their formation. This work was developed in two distinct and complementary levels: a scientific level, aimed to advance the understanding of particle formation and a more technical level, dedicated to instrument development and characterization. Understanding and characterizing aerosol formation, is important, as formation of aerosol particles from precursor gases is one of the main sources of atmospheric aerosols. Elucidating how aerosol formation proceeds in detail is critical to better quantify aerosol contribution to the Earth's radiation budget. Experimentally characterizing the first steps of aerosol formation is the key to understanding this phenomenon. Developing and characterizing suitable instrumentation to measure clusters and ions in the sub 3 nm range, where aerosol formation starts, is necessary to clarify the processes that lead to aerosol formation. This thesis presents the results of a series of experimental studies of sub 3 nm aerosol particles and ions. It also shows the results of the technical characterization and instrument development that were made in the process. Specifically, we describe three scientific results achieved from chamber experiments. Firstly the relative contributions of sulfuric acid, ammonia and ions in nucleation processes was quantified experimentally, supporting that sulfuric acid alone cannot explain atmospheric observation of nucleation rates. Secondly, the chemical composition of cluster ions was directly measured for a ternary system, where sulfuric acid, ammonia and water were the condensable vapors. In these measurements we observed a decreasing acidity of the clusters with increasing concentration of gas phase ammonia, with the ratio of sulfuric acid/ammonia staying closer to that of ammonium bisulfate than to that of ammonium sulfate. Finally, in a series of chamber experiments the ion ion recombination coefficient was quantified at different conditions. The ion ion recombination coefficient is a basic physical quantity for modeling ion induced and ion mediated nucleation. We observed a steep increase in the ion ion recombination coefficient with decreasing temperatures and with decreasing relative humidity. This thesis also reviews technical results of: 1) laboratory verification, characterization and testing of different aerosol and ion instruments measuring in the sub 3 nm range; 2) the development of new inlets for such instruments to improve the detection of sub-3 nm particles and ions.Tämä väitöstutkimus keskittyy ilmakehän sekundääristen aerosolihiukkasten ja ionien muodostumisen kokeelliseen tutkimiseen. Tässä työssä saatiin uutta tietoa hiukkasmuodostuksesta, sekä kehitettiin ja karakterisoitiin pienimpien muodostuneiden hiukkasten mittaamiseen soveltuvia mittalaitteita. Ilmakehän aerosolihiukkaset vaikuttavat muun muassa maapallon säteilytasapainoon. Aerosolien muodostuminen kaasuista on yksi niiden merkittävimmistä lähteistä ilmakehässä. Siksi niiden muodostumisprosessien ymmärtäminen on tärkeää. Näiden prosessien tutkimiseen tarvitaan mittalaitteita, joilla voidaan havaita alle 3 nm:n kokoisia molekyyliklustereita ja ioneja. Tässä väitöskirjatyössä kehitettiin tähän tarkoitukseen soveltuvia mittalaitteita. Tämän tutkimuksen kolme tärkeintä tulosta ovat: 1) Rikkihapon, ammoniakin ja ionien merkitystä hiukkasmuodostuksessa tutkittiin kokeellisesti, ja havaittiin että rikkihappo ei yksinään selitä ilmakehässä havaittuja hiukkasten muodostumisnopeuksia. 2) Rikkihapon, ammoniakin ja veden muodostamassa systeemissä klusteri-ionien happamuuden havaittiin vähenevän kaasumaisen ammoniakin pitoisuuden kasvaessa. Rikkihapon ja ammoniakin välinen suhde klustereissa oli lähempänä ammoniumbisulfaattia kuin ammoniumsulfaattia. 3) Kammiomittauksissa määritettiin ionien rekombinaatiokerroin erilaisissa olosuhteissa. Rekombinaatiokerroin on suure, jolla on merkitystä ionien aiheuttamassa hiukkasmuodostuksessa. Sen havaittiin kasvavan jyrkästi sekä lämpötilan että suhteellisen kosteuden laskiessa. Edellämainittujen tulosten lisäksi väitöskirjatyössä testattiin ja karakterisoitiin laboratorio-olosuhteissa erilaisia alle 3 nm:n hiukkasten havaitsemiseen soveltuvia hiukkas- ja ionimittalaitteita, sekä kehitettiin näihin laitteisiin sopivat näytteenottolinjat, jotka parantavat pienimpien hiukkasten ja molekyyliklustereiden havaitsemista

Ion production rates and cross-sections from the atmospheric observations and comparison with the CLOUD experiment results

We present and discuss experimental results obtained from the measurements of cosmic ray fluxes and ion concentrations at different altitudes (from ground level up to 30-35 km) and latitudes (from equator to polar regions) in the Earth's atmosphere. We calculated ionproduction cross-sections and ion production rates from these data sets. The same characteristics are possible to be derived from the CLOUD experimental data using ion concentrations, particle beam intensities, etc. We discuss the methods of estimation of these characteristics in the CLOUD experiment

Real-practice thromboprophylaxis in atrial fibrillation

This retrospective observational study was based on databases of the Local Health Authority of Treviso, Italy. It evaluated the prevalence and the effectiveness of oral anticoagulation treatment (OAT) for the management of nonvalvular atrial fibrillation (NVAF) in everyday clinical practice. Out of 6,138 NVAF patients, only 3,024 received Vitamin K antagonist (VKA). Potential barriers decreasing the probability of being treated with VKA were female sex, older age, antiplatelet treatment and history of bleeding. In addition, VKA-treatment was not in line with current ESC and AIAC guidelines, since the patients at high or low risk of stroke were under-or over-treated, resp. Among VKAtreated patients, 73 % of subjects were not at target with anticoagulation. OAT resulted to be effective in reducing stroke risk. However, stroke events were significantly influenced also by previous stroke or transient ischemic attack (hazard ratio, HR = 2.99, p < 0.001) and by previous bleeding events (HR = 1.60, p < 0.001)

West Nile virus infection in individuals with pre-existing Usutu virus immunity, northern Italy, 2018

In 2018, there was a large West Nile virus (WNV) outbreak in northern Italy. We observed five atypical cases of WNV infection that were characterised by the presence of WNV RNA and WNV IgG at the time of diagnosis, but no IgM response during follow-up. Neutralisation assays demonstrated pre-existing Usutu virus immunity in all patients. Besides challenging diagnosis, the immunological crosstalk between the two viruses warrants further investigation on possible cross-protection or infection enhancement effects

Total endovascular treatment for extent type 1 and 5 thoracoabdominal aortic aneurysms

OBJECTIVE: The study objective was to describe the results of thoracic endovascular aortic repair with the intentional coverage of the celiac artery and distal supramesenteric landing zone for extent type 1 and type 5 thoracoabdominal aortic aneurysms. METHODS: Inclusion criteria were thoracic endovascular aortic repair with celiac artery coverage to treat elective or urgent extent type 1 and 5 thoracoabdominal aortic aneurysms. Primary end points were in-hospital and follow-up survival, freedom from aortic-related mortality, and freedom from reintervention. RESULTS: Thoracoabdominal disease extent was type 1 in 12 patients (71%) and type 5 in 5 patients (29%). Urgent repair was performed in 4 patients (23.5%). Primary technical success was 100%. Early mortality and visceral ischemia did not occur. Permanent spinal cord ischemia rate was 6% (n = 1). Follow-up ranged from 3 to 120 months (interquartile range, 12-36.5). Survival estimate was 85% \ub1 9% (95% confidence interval, 67-94) at 1 year and 49% \ub1 17% (95% confidence interval, 21-78) at 5 years. Cumulative freedom from aortic-related mortality was 94%, and estimated freedom from reintervention at 1 and 5 years was 93% \ub1 7% (95% confidence interval, 68-99). Neither type 1 endoleaks nor distal stent-graft migration causing superior mesenteric artery occlusion was detected. CONCLUSIONS: Thoracic endovascular aortic repair with intentional coverage of celiac artery for extent 1 and 5 thoracoabdominal aortic aneurysms had satisfactory results in selected patients at high risk for open repair. Visceral ischemia did not occur, but spinal cord ischemia is still high at 6%. At midterm follow-up, neither endoleak development nor aortic reintervention was related to the inadequate distal landing zone. Follow-up survival is satisfactory and comparable to open repair

Performance of diethylene glycol based particle counters in the sub 3 nm size range [Discussion paper]

When studying new particle formation, the uncertainty in determining the "true" nucleation rate is considerably reduced when using Condensation Particle Counters (CPCs) capable of measuring concentrations of aerosol particles at sizes close to or even at the critical cluster size (1–2 nm). Recently CPCs, able to reliably detect particles below 2 nm in size and even close to 1 nm became available. The corrections needed to calculate nucleation rates are substantially reduced compared to scaling the observed formation rate to the nucleation rate at the critical cluster size. However, this improved instrumentation requires a careful characterization of their cut-off size and the shape of the detection efficiency curve because relatively small shifts in the cut-off size can translate into larger relative errors when measuring particles close to the cut-off size. Here we describe the development of two continuous flow CPCs using diethylene glycol (DEG) as the working fluid. The design is based on two TSI 3776 counters. Several sets of measurements to characterize their performance at different temperature settings were carried out. Furthermore two mixing-type Particle Size Magnifiers (PSM) A09 from Airmodus were characterized in parallel. One PSM was operated at the highest mixing ratio (1 L min−1 saturator flow), and the other was operated in a scanning mode, where the mixing ratios are changed periodically, resulting in a range of cut-off sizes. Different test aerosols were generated using a nano-Differential Mobility Analyzer (nano-DMA) or a high resolution DMA, to obtain detection efficiency curves for all four CPCs. One calibration setup included a high resolution mass spectrometer (APi-TOF) for the determination of the chemical composition of the generated clusters. The lowest cut-off sizes were achieved with negatively charged ammonium sulphate clusters, resulting in cut-offs of 1.4 nm for the laminar flow CPCs and 1.2 and 1.1 nm for the PSMs. A comparison of one of the laminar-flow CPCs and one of the PSMs measuring ambient and laboratory air showed good agreement between the instruments

cost of illness study of diabetes mellitus focus on patients with type 2 diabetes

ObjectiveThe aim of the study was to assess the cost of management of diabetic patients; moreover, for type 2 not insulin-dependent patients, also the durability of treatments was evaluated, in ord..

dapagliflozin as add on to metformin network meta analysis and budget impact analysis

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On the accuracy of ion measurements using a neutral cluster and air ion spectrometer

Here, we present a calibration of the Neutral cluster and Air Ion Spectrometer (NAIS, Airel Ltd.) for the size and concentration of ions in the mobility-diameter size-range 0.98-29.1 nm. Previous studies raised accuracy issues in size and concentration determination and highlighted the importance of used data inversion algorithm. Therefore, we investigated the performance of the NAIS by using five inversion methods. The presented results illustrate that the size information given by the NAIS is very accurate, regardless of the version of the data inversion. The number concentrations determined by the NAIS were 15%-30% too low especially at the lower end of the measurement size range (<5 nm), whereas concentrations at diameters 19.6 nm and larger were overestimated by up to 8%. With the correction presented in this study, the uncertainty of the ion concentration measurement of the NAIS can be reduced to less than 10%, allowing the NAIS to be used in quantitative ion cluster studies and more accurate determination of formation and growth rates.Peer reviewe

Measurements of cluster ions using a nano radial DMA and a particle size magnifier in CLOUD

We built a new instrumental setup for measuring ion distributions in the size range [1.3-6] nm. The implementation of an high transmission inlet increased the total transmission efficiency to more than 6% at 1.47 nm mobility equivalent diameter, allowing the detection of ions at atmospheric concentrations. The size resolution of our measurements is as high as 6. We characterized the instrument in the laboratory and carried out measurements during the CLOUD7 campaign. We compared the results obtained with the Neutral cluster and Air Ion spectrometer finding very good agreement