Towards data-driven mass spectrometry in atmospheric science

Aerosols found in the atmosphere affect the climate and worsen air quality. To mitigate these adverse impacts, aerosol formation and aerosol chemistry in the atmosphere need to be better mapped out and understood. Currently, mass spectrometry is the single most important analytical technique in atmospheric chemistry and is used to track and identify compounds and processes. Vast amounts of data are collected in each measurement of current time-of-flight and orbitrap mass spectrometers using modern rapid data acquisition practices. However, compound identification remains as a major bottleneck during data analysis due to lacking reference libraries and analysis tools. Data-driven compound identification approaches could alleviate the problem, yet remain rare to non-existent in atmospheric science. In this perspective, we review the current state of data-driven compound identification with mass spectrometry in atmospheric science, and discuss current challenges and possible future steps towards a digital mass spectrometry era in atmospheric science

Drought effects on volatile organic compound emissions from Scots pine stems

Tree stems have been identified as sources of volatile organic compounds (VOCs) that play important roles in tree defence and atmospheric chemistry. Yet, we lack understanding on the magnitude and environmental drivers of stem VOC emissions in various forest ecosystems. Due to the increasing importance of extreme drought, we studied drought effects on the VOC emissions from mature Scots pine (Pinus sylvestris L.) stems. We measured monoterpenes, acetone, acetaldehyde and methanol emissions with custom-made stem chambers, online PTR-MS and adsorbent sampling in a drought-prone forest over the hot-dry summer of 2018 and compared the emission rates and dynamics between trees in naturally dry conditions and under long-term irrigation (drought release). The pine stems were significant monoterpene sources. The stem monoterpene emissions potentially originated from resin, based on their similar monoterpene spectra. The emission dynamics of all VOCs followed temperature at a daily scale, but monoterpene and acetaldehyde emission rates decreased nonlinearly with drought over the summer. Despite the dry conditions, large peaks of monoterpene, acetaldehyde and acetone emissions occurred in late summer potentially due to abiotic or biotic stressors. Our results highlight the potential importance of stem emissions in the ecosystem VOC budget, encouraging further studies in diverse environments.Peer reviewe

Scots Pine Stems as Dynamic Sources of Monoterpene and Methanol Emissions

Funding Information: We are grateful for the funding received from Academy of Finland Center of Excellence program (Grant No. 307331), the University of Helsinki Center for Environment HENVI, the Nordic Center of Excellence CRAICC and the University of Helsinki Doctoral program AGFOREE. Publisher Copyright: © Copyright © 2020 Vanhatalo, Aalto, Chan, Hölttä, Kolari, Rissanen, Kabiri, Hellén and Bäck.The volatile organic compound (VOC) fluxes of living plant compartments other than foliage are poorly known. In this paper we describe for the first time the methanol and monoterpene fluxes from living Scots pine stems in situ, over 4 years at the SMEAR II station in southern Finland. The VOC fluxes from stems were measured online with an automated chamber measurement system. Both methanol and monoterpene emissions showed strong diurnal and seasonal cycles. Methanol emission rates were highest in mid-summer, and coincided with the most intensive period of stem radial growth. Methanol emission rates correlated moderately with the xylem sap flow rate and foliage transpiration rate, which suggests that many simultaneous and overlapping processes are related to methanol transport and production in trees. Monoterpene emissions from stems were highest on the hottest summer days, but also substantial in winter during times when the temperature was above zero °C for several days. Overall, the emissions from stems constitute about 2% of the whole stand monoterpene emissions under normal, non-stressed conditions. This can be used in stand monoterpene emission models as the rough estimate of woody compartment contribution.Peer reviewe

Diurnal patterns in Scots pine stem oleoresin pressure in a boreal forest

Coniferous tree stems contain large amounts of oleoresin under positive pressure in the resin ducts. Studies in North-American pines indicated that the stem oleoresin exudation pressure (OEP) correlates negatively with transpiration rate and soil water content. However, it is not known how the OEP changes affect the emissions of volatile vapours from the trees. We measured the OEP, xylem diameter changes indicating changes in xylem water potential and monoterpene emissions under field conditions in mature Scots pine (Pinus sylvestris L.) trees in southern Finland. Contrary to earlier reports, the diurnal OEP changes were positively correlated with temperature and transpiration rate. OEP was lowest at the top part of the stem, where water potentials were also more negative, and often closely linked to ambient temperature and stem monoterpene emissions. However, occasionally OEP was affected by sudden changes in vapour pressure deficit (VPD), indicating the importance of xylem water potential on OEP as well. We conclude that the oleoresin storage pools in tree stems are in a dynamic relationship with ambient temperature and xylem water potential, and that the canopy monoterpene emission rates may therefore be also regulated by whole tree processes and not only by the conditions prevailing in the upper canopy.Peer reviewe

Family's socioeconomic profile at birth and offspring mortality until midlife - The Northern Finland Birth Cohort 1966 study

Family's socioeconomic profile collected prenatally is known to predict offspring mortality during early life, but it remains unclear whether it has the potential to predict offspring mortality until later life. In this study, 12,063 individuals belonging to the Northern Finland Birth Cohort 1966 were followed up from mid-pregnancy for 52 years (570,000 person years). Five distinct socioeconomic profiles were identified by latent class analysis based on mother's marital status, education, and occupation; father's occupation; number of family members; location of residence, room count, and utilities; and family's wealth. The classes were highest status families (15.4% of the population), small families (22.1%), larger families (15.4%), average wealth families (23.4%), and rural families (23.3%). Their associations to offspring mortality, via linkage to national offspring death records, were analysed by Cox regression, stratified by sex and age groups (0-19, 20-38 and 40-52 years). In total, mortality was 9.2% among male and 5.0% among female offspring. Risk for midlife mortality was higher among male offspring from larger families (hazard ratio 2.19, 95% confidence interval 1.32-3.63), average wealth families (1.66, 1.02-2.73) and rural families (1.63, 1.00-2.68), relative to offspring from highest status families. It seems that family's socioeconomic profile constructed prenatally has predictive value for midlife mortality among male offspring. Premature mortality of men and women seem to be two distinct phenomena with differing underlying factors as socioeconomic profile was not associated with mortality among female offspring.Peer reviewe

Progressive dopaminergic defect in a patient with primary progressive multiple sclerosis

Dopamine has a modulatory role in a number of autoimmune diseases, but there are no published cases of longitudinal dopaminergic imaging in multiple sclerosis (MS). Here we report a patient with primary progressive multiple sclerosis (PPMS) who was scanned twice with brain dopamine transporter single photon emission computed tomography (SPECT) with an interval of four years. The results showed a loss of tracer binding that corresponded to a 4–7 fold steeper decline than in normal ageing. The finding points to a relevant role of nigrostriatal dopaminergic degeneration in the pathological process of PPMS.</p

Assessing the utilization of the decision to implement a palliative goal for the treatment of cancer patients during the last year of life at Helsinki University Hospital : a historic cohort study

Background: To avoid aggressive treatments at the end-of-life and to provide palliative care (PC), physicians need to terminate futile anti-cancer treatments and define the palliative goal of the treatment in time. This single center study assesses the practices used to make the decision that leads to treatment with a palliative goal, i.e., the PC decision and its effect on anti-cancer treatments at the end of life. Material and methods: Patients with a cancer diagnosis treated in tertiary hospital during 1st January 2013 - 31st December 2014 and deceased by the end of 2014 were identified in the hospital database (N = 2737). Of these patients, 992 were randomly selected for this study. The PC decision was screened from patient records, i.e., termination of cancer-specific treatments and a focus on symptom-centered PC. Results: The PC decision was defined in 82% of the patients during the last year of life (49% >30 days and 33%Peer reviewe

Maantieteen kenttäkurssin järjestäminen etäopetuksena koronapandemian aikana

Non peer reviewe