Analyses of regulatory CD4(+)CD25(+)FOXP3(+) T cells and observations from peripheral T cell subpopulation markers during the development of type 1 diabetes in children

Our aim was to study whether the aberrant amount or function of regulatory T cells is related to the development of type 1 diabetes (T1D) in children. We also set out to investigate the balance of different T cell subtype markers during the T1D autoimmune process. Treg cells were quantified with flow cytometric assay, and the suppression capacity was analysed with a carboxyfluorescein succinimidyl ester (CFSE)-based T cell suppression assay in children in various phases of T1D disease process and in healthy autoantibody-negative control children. The mRNA expression of different T cell subpopulation markers was analysed with real-time qPCR method. The proportion and suppression capacity of regulatory T cells were similar in seroconverted children at an early stage of beta cell autoimmunity and also in children with T1D when compared to healthy and autoantibody-negative children. Significant differences were observed in the mRNA expression of different T cell subpopulation markers in prediabetic children with multiple (2) autoantibodies and in children with newly diagnosed T1D when compared to the control children. In conclusion, there were no quantitative or functional differences in regulatory T cells between the case and control groups in any phase of the autoimmune process. Decreased mRNA expression levels of T cell subtype markers were observed in children with multiple islet autoantibodies and in those with newly diagnosed T1D, probably reflecting an exhaustion of the immune system after the strong immune activation during the autoimmune process or a generally aberrant immune response related to the progression of the disease.Peer reviewe

Changes in background aerosol composition in Finland during polluted and clean periods studied by TEM/EDX individual particle analysis

Aerosol samples were collected at a rural background site in southern Finland in May 2004 during pollution episode ( PM1 similar to 16 mu g m(-3), backward air mass trajectories from south-east), intermediate period (PM1 similar to 5 mu g m(-3), backtrajectories from north-east) and clean period (PM1 similar to 2 mu g m(-3), backtrajectories from northwest/ north). The elemental composition, morphology and mixing state of individual aerosol particles in three size fractions were studied using transmission electron microscopy (TEM) coupled with energy dispersive X-ray (EDX) microanalyses. The TEM/EDX results were complemented with the size-segregated bulk chemical measurements of selected ions and organic and elemental carbon. Many of the particles in PM0.2-1 and PM1-3.3 size fractions were strongly internally mixed with S, C and/or N. The major particle types in PM0.2-1 samples were 1) soot and 2) ( ammonium) sulphates and their mixtures with variable amounts of C, K, soot and/or other inclusions. Number proportions of those two particle groups in PM0.2-1 samples were 0 - 12% and 83 - 97%, respectively. During the pollution episode, the proportion of Ca-rich particles was very high ( 26 - 48%) in the PM1- 3.3 and PM3.3-11 samples, while the PM0.2-1 and PM1- 3.3 samples contained elevated proportions of silicates ( 22 - 33%), metal oxides/hydroxides ( 1 - 9%) and tar balls ( 1 - 4%). These aerosols originated mainly from polluted areas of Eastern Europe, and some open biomass burning smoke was also brought by long-range transport. During the clean period, when air masses arrived from the Arctic Ocean, PM1- 3.3 samples contained mainly sea salt particles ( 67 - 89%) with a variable rate of Cl substitution ( mainly by NO3-). During the intermediate period, the PM1- 3.3 sample contained porous (sponge-like) Na-rich particles (35%) with abundant S, K and O. They might originate from the burning of wood pulp wastes of paper industry. The proportion of biological particles and C-rich fragments ( probably also biological origin) were highest in the PM3.3-11 samples ( 0 - 81% and 0 - 22%, respectively). The origin of different particle types and the effect of aging processes on particle composition and their hygroscopic and optical properties are discussed.Aerosol samples were collected at a rural background site in southern Finland in May 2004 during pollution episode ( PM1 similar to 16 mu g m(-3), backward air mass trajectories from south-east), intermediate period (PM1 similar to 5 mu g m(-3), backtrajectories from north-east) and clean period (PM1 similar to 2 mu g m(-3), backtrajectories from northwest/ north). The elemental composition, morphology and mixing state of individual aerosol particles in three size fractions were studied using transmission electron microscopy (TEM) coupled with energy dispersive X-ray (EDX) microanalyses. The TEM/EDX results were complemented with the size-segregated bulk chemical measurements of selected ions and organic and elemental carbon. Many of the particles in PM0.2-1 and PM1-3.3 size fractions were strongly internally mixed with S, C and/or N. The major particle types in PM0.2-1 samples were 1) soot and 2) ( ammonium) sulphates and their mixtures with variable amounts of C, K, soot and/or other inclusions. Number proportions of those two particle groups in PM0.2-1 samples were 0 - 12% and 83 - 97%, respectively. During the pollution episode, the proportion of Ca-rich particles was very high ( 26 - 48%) in the PM1- 3.3 and PM3.3-11 samples, while the PM0.2-1 and PM1- 3.3 samples contained elevated proportions of silicates ( 22 - 33%), metal oxides/hydroxides ( 1 - 9%) and tar balls ( 1 - 4%). These aerosols originated mainly from polluted areas of Eastern Europe, and some open biomass burning smoke was also brought by long-range transport. During the clean period, when air masses arrived from the Arctic Ocean, PM1- 3.3 samples contained mainly sea salt particles ( 67 - 89%) with a variable rate of Cl substitution ( mainly by NO3-). During the intermediate period, the PM1- 3.3 sample contained porous (sponge-like) Na-rich particles (35%) with abundant S, K and O. They might originate from the burning of wood pulp wastes of paper industry. The proportion of biological particles and C-rich fragments ( probably also biological origin) were highest in the PM3.3-11 samples ( 0 - 81% and 0 - 22%, respectively). The origin of different particle types and the effect of aging processes on particle composition and their hygroscopic and optical properties are discussed.Aerosol samples were collected at a rural background site in southern Finland in May 2004 during pollution episode ( PM1 similar to 16 mu g m(-3), backward air mass trajectories from south-east), intermediate period (PM1 similar to 5 mu g m(-3), backtrajectories from north-east) and clean period (PM1 similar to 2 mu g m(-3), backtrajectories from northwest/ north). The elemental composition, morphology and mixing state of individual aerosol particles in three size fractions were studied using transmission electron microscopy (TEM) coupled with energy dispersive X-ray (EDX) microanalyses. The TEM/EDX results were complemented with the size-segregated bulk chemical measurements of selected ions and organic and elemental carbon. Many of the particles in PM0.2-1 and PM1-3.3 size fractions were strongly internally mixed with S, C and/or N. The major particle types in PM0.2-1 samples were 1) soot and 2) ( ammonium) sulphates and their mixtures with variable amounts of C, K, soot and/or other inclusions. Number proportions of those two particle groups in PM0.2-1 samples were 0 - 12% and 83 - 97%, respectively. During the pollution episode, the proportion of Ca-rich particles was very high ( 26 - 48%) in the PM1- 3.3 and PM3.3-11 samples, while the PM0.2-1 and PM1- 3.3 samples contained elevated proportions of silicates ( 22 - 33%), metal oxides/hydroxides ( 1 - 9%) and tar balls ( 1 - 4%). These aerosols originated mainly from polluted areas of Eastern Europe, and some open biomass burning smoke was also brought by long-range transport. During the clean period, when air masses arrived from the Arctic Ocean, PM1- 3.3 samples contained mainly sea salt particles ( 67 - 89%) with a variable rate of Cl substitution ( mainly by NO3-). During the intermediate period, the PM1- 3.3 sample contained porous (sponge-like) Na-rich particles (35%) with abundant S, K and O. They might originate from the burning of wood pulp wastes of paper industry. The proportion of biological particles and C-rich fragments ( probably also biological origin) were highest in the PM3.3-11 samples ( 0 - 81% and 0 - 22%, respectively). The origin of different particle types and the effect of aging processes on particle composition and their hygroscopic and optical properties are discussed.Peer reviewe

Future biogeochemical forcing in Eastern Siberia: cooling or warming?

Over-proportional warming in the northern high latitudes, and large carbon stocks in boreal and (sub)arctic ecosystems have raised concerns as to whether substantial positive climate feedbacks from biogeochemical process responses should be expected. Such feedbacks occur if increasing temperatures lead to e.g., a net release of CO2 or CH4. However, temperature-enhanced emissions of biogenic volatile organic compounds (BVOC) have been shown to contribute to a cooling feedback via growth of secondary organic aerosol (SOA), and related aerosol forcings. Combining measurements in Eastern Siberia with model-based estimates of vegetation and permafrost dynamics, BVOC emissions and aerosol growth, we show here that the additional climate forcing from changes in ecosystem CO2 balance and BVOC-SOA interactions nearly cancel on a regional scale. The interactions between emissions and vegetation dynamics that underlie individual forcing estimates are complex and highlight the importance of addressing ecosystem-climate feedbacks in consistent, process-based model frameworks that account for a multitude of system processes

Nanoparticle ranking analysis: determining new particle formation (NPF) event occurrence and intensity based on the concentration spectrum of formed (sub-5 nm) particles

Here we introduce a new method, termed “nanoparticle ranking analysis”, for characterizing new particle formation (NPF) from atmospheric observations. Using daily variations of the particle number concentration at sizes immediately above the continuous mode of molecular clusters, here in practice 2.5–5 nm (i.e. ΔN2.5−5), we can determine the occurrence probability and estimate the strength of atmospheric NPF events. After determining the value of ΔN2.5−5 for all the days during a period under consideration, the next step of the analysis is to rank the days based on this simple metric. The analysis is completed by grouping the days either into a number of percentile intervals based on their ranking or into a few modes in the distribution of log (ΔN2.5−5) values. Using 5 years (2018–2022) of data from the SMEAR II station in Hyytiälä, Finland, we found that the days with higher (lower) ranking values had, on average, both higher (lower) probability of NPF events and higher (lower) particle formation rates. The new method provides probabilistic information about the occurrence and intensity of NPF events and is expected to serve as a valuable tool to define the origin of newly formed particles at many types of environments that are affected by multiple sources of aerosol precursors.</p

Aerosol charging state at an urban site: new analytical approach and implications for ion-induced nucleation

The charging state of aerosol populations was determined using an Ion-DMPS in Helsinki, Finland between December 2008 and February 2010. We extrapolated the charging state and calculated the ion-induced nucleation fraction to be around 1.3 % ± 0.4 % at 2 nm and 1.3 % ± 0.5 % at 1.5 nm, on average. We present a new method to retrieve the average charging state for a new particle formation event, at a given size and polarity. We improve the uncertainty assessment and fitting technique used previously with an Ion-DMPS. We also use a new theoretical framework that allows for different concentrations of small ions for different polarities (polarity asymmetry). We extrapolate the ion-induced fraction using polarity symmetry and asymmetry. Finally, a method to calculate the growth rates from the behaviour of the charging state as a function of the particle diameter using polarity symmetry and asymmetry is presented and used on a selection of new particle formation events

Future vegetation–climate interactions in Eastern Siberia: an assessment of the competing effects of CO2 and secondary organic aerosols

Disproportional warming in the northern high latitudes, and large carbon stocks in boreal and (sub)arctic ecosystems have raised concerns as to whether substantial positive climate feedbacks from biogeochemical process responses should be expected. Such feedbacks occur if increasing temperatures lead to e.g. a net release of CO2 or CH4. However, temperature-enhanced emissions of biogenic volatile organic compounds (BVOC) have been shown to contribute to the growth of secondary organic aerosol (SOA) which is known to have a negative radiative climate effect. Combining measurements in Eastern Siberia with model-based estimates of vegetation and permafrost dynamics, BVOC emissions and aerosol growth, we assess here possible future changes in ecosystem CO2 balance and BVOC-SOA interactions, and discuss these changes in terms of possible climate effects. On global level, both are very small but when concentrating on Siberia and the northern hemisphere the negative forcing from changed aerosol direct and indirect effects become notable – even though the associated temperature response would not necessarily follow a similar spatial pattern. While our analysis does not include other important processes that are of relevance for the climate system, the CO2 and BVOC-SOA interplay used serves as an example of the complexity of the interactions between emissions and vegetation dynamics that underlie individual terrestrial feedbacks and highlights the importance of addressing ecosystem-climate feedbacks in consistent, process-based model frameworks

Intercomparison of air ion spectrometers: An evaluation of results in varying conditions

We evaluated 11 air ion spectrometers from Airel Ltd. after they had spent one year in field measurements as a part of the EUCAARI project: 5 Air Ion Spectrometers (AIS), 5 Neutral cluster and Air Ion Spectrometers (NAIS) and one Airborne NAIS (ANAIS). This is the first time that an ANAIS is evaluated and compared so extensively. The ion spectrometers' mobility and concentration accuracy was evaluated. Their measurements of ambient air were compared between themselves and to reference instruments: a Differential Mobility Particle Sizer (DMPS), a Balanced Scanning Mobility Analyzer (BSMA), and an Ion-DMPS. We report on the simultaneous measurement of a new particle formation (NPF) event by all 11 instruments and the 3 reference instruments. To our knowledge, it is the first time that the size distribution of ions and particles is measured by so many ion spectrometers during a NPF event. The new particle formation rates (~0.2 cm−3 s−1 for ions and ~2 cm−3 s−1 for particles) and growth rates (~25 nm h−1 in the 3–7 nm size range) were calculated for all the instruments. The NAISs and the ANAIS gave higher concentrations and formation rates than the AISs. For example, the AISs agreed with the BSMA within 11 % and 28 % for negative and positive ion concentration respectively, whereas the NAISs agreed within 23 % and 29 %. Finally, based on the results presented here, we give guidelines for data evaluation, when data from different individual ion spectrometers are compared

Size distributions, sources and source areas of water-soluble organic carbon in urban background air

International audienceThis paper represents the results of one year long measurement period of the size distributions of water-soluble organic carbon (WSOC), inorganic ions and gravimetric mass of particulate matter. Measurements were done at an urban background station (SMEAR III) by using a micro-orifice uniform deposit impactor (MOUDI). The site is located in northern European boreal region in Helsinki, Finland. The WSOC size distribution measurements were completed with the chemical analysis of inorganic ions, organic carbon (OC) and monosaccharide anhydrides from the filter samples. During the measurements gravimetric mass in the MOUDI collections varied between 3.4 and 55.0 ?g m?3 and the WSOC concentration was between 0.3 and 7.4 ?g m?3. On average, water-soluble particulate organic matter (WSPOM, WSOC multiplied by 1.6) comprised 25±7.7% and 7.5±3.4% of aerosol PM1 mass and the PM1?10 mass, respectively. Inorganic ions contributed 33±12% and 28±19% of the analyzed PM1 and PM1?10 aerosol mass. Five different aerosol categories corresponding to different sources or source areas were identified (long-range transport aerosols, biomass burning aerosols from wild land fires and from small-scale wood combustion, aerosols originating from marine areas and from the clean arctic areas). Clear differences in WSOC concentrations and size distributions originating from different sources or source areas were observed, although there are also many other factors which might affect the results. E.g. the local conditions and sources of volatile organic compounds (VOCs) and aerosols as well as various transformation processes are likely to have an impact on the measured aerosol composition. Using the source categories, it was identified that especially the oxidation products of biogenic VOCs in summer had a clear effect on WSOC concentrations