| 1. |
- Graco-Roza, Caio, et al.
(författare)
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Distance decay 2.0 – A global synthesis of taxonomic and functional turnover in ecological communities
- 2022
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 31:7, s. 1399-1421
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Understanding the variation in community composition and species abundances (i.e., beta-diversity) is at the heart of community ecology. A common approach to examine beta-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments.Location: Global.Time period: 1990 to present.Major taxa studied: From diatoms to mammals.Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features.Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances.Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments.
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| 2. |
- Vuorinen, V., et al.
(författare)
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Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors
- 2020
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Ingår i: Safety Science. - : Elsevier BV. - 0925-7535. ; 130
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Tidskriftsartikel (refereegranskat)abstract
- We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic. We utilize physics-based modeling at different levels of complexity, along with previous literature on coronaviruses, to investigate the possibility of airborne transmission. The previous literature, our 0D-3D simulations by various physics-based models, and theoretical calculations, indicate that the typical size range of speech and cough originated droplets (d⩽20μm) allows lingering in the air for O(1h) so that they could be inhaled. Consistent with the previous literature, numerical evidence on the rapid drying process of even large droplets, up to sizes O(100μm), into droplet nuclei/aerosols is provided. Based on the literature and the public media sources, we provide evidence that the individuals, who have been tested positive on COVID-19, could have been exposed to aerosols/droplet nuclei by inhaling them in significant numbers e.g. O(100). By 3D scale-resolving computational fluid dynamics (CFD) simulations, we give various examples on the transport and dilution of aerosols (d⩽20μm) over distances O(10m) in generic environments. We study susceptible and infected individuals in generic public places by Monte-Carlo modelling. The developed model takes into account the locally varying aerosol concentration levels which the susceptible accumulate via inhalation. The introduced concept, ’exposure time’ to virus containing aerosols is proposed to complement the traditional ’safety distance’ thinking. We show that the exposure time to inhale O(100) aerosols could range from O(1s) to O(1min) or even to O(1h) depending on the situation. The Monte-Carlo simulations, along with the theory, provide clear quantitative insight to the exposure time in different public indoor environments.
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| 3. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 4. |
- van Dongen, M. M. E., et al.
(författare)
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Use of antihypertensive medication after ischemic stroke in young adults and its association with long-term outcome
- 2019
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Ingår i: Annals of Medicine. - : Informa UK Limited. - 0785-3890 .- 1365-2060. ; 51:1, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- Background: Knowledge on the use of secondary preventive medication in young adults is limited. Methods: We included 936 first-ever ischemic stroke 30-day survivors aged 15-49, enrolled in the Helsinki Young Stroke Registry, 1994-2007. Follow-up data until 2012 came from Finnish Care Register, Statistics Finland, and Social Insurance Institution of Finland. Usage thresholds were defined as non-users, low (prescription coverage <30%), intermediate (30-80%) and high users (>80%). Adjusted Cox regression allowed assessing the association of usage with all-cause mortality and recurrent vascular events. Results: Of our patients, 40.5% were non-users, 7.8% had low usage, 11.8% intermediate usage and 40.0% high usage. Median follow-up was 8.3 years. Compared to non-users, risk of mortality and recurrent stroke or TIA was lower for patients with low-intermediate (HR 0.40, 95% CI 0.22-0.65; HR 0.31, 95% CI 0.18-0.53) and high usage (HR 0.25, 95% CI 0.15-0.42; HR 0.30, 95% CI 0.19-0.46), after adjustment for confounders. Conclusions: Use of antihypertensives was suboptimal in one-third of patients in whom antihypertensives were initially prescribed. Users were at lower risk of mortality and recurrent stroke or TIA compared to non-users.Key Messages The use of antihypertensive medication is suboptimal in one-third of patients in whom antihypertensive medication was initially prescribed after ischemic stroke at young age. The risk of mortality and recurrent stroke or TIA is lower for users of antihypertensive medication after ischemic stroke at young age compared to non-users, after adjustment for relevant confounders including pre-existing hypertension and prior use of antihypertensive medication. Specific guidelines on antihypertensive medication use after ischemic stroke at young age are lacking. However, our results may motivate doctors and patients in gaining better usage of antihypertensive medication, since better usage was associated with more favorable outcome in this study.
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| 5. |
- Snellman, Anniina, et al.
(författare)
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ASIC-E4: Interplay of Beta-Amyloid, Synaptic Density and Neuroinflammation in Cognitively Normal Volunteers With Three Levels of Genetic Risk for Late-Onset Alzheimer's Disease - Study Protocol and Baseline Characteristics
- 2022
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background:& nbsp;Detailed characterization of early pathophysiological changes in preclinical Alzheimer's disease (AD) is necessary to enable development of correctly targeted and timed disease-modifying treatments. ASIC-E4 study ( "Beta-Amyloid, Synaptic loss, Inflammation and Cognition in healthy APOE epsilon 4 carriers ") combines state-of-the-art neuroimaging and fluid-based biomarker measurements to study the early interplay of three key pathological features of AD, i.e., beta-amyloid (A beta) deposition, neuroinflammation and synaptic dysfunction and loss in cognitively normal volunteers with three different levels of genetic (APOE-related) risk for late-onset AD.& nbsp;Objective:& nbsp;Here, our objective is to describe the study design, used protocols and baseline demographics of the ASIC-E4 study.& nbsp;Methods/Design:& nbsp;ASIC-E4 is a prospective observational multimodal imaging study performed in Turku PET Centre in collaboration with University of Gothenburg. Cognitively normal 60-75-year-old-individuals with known APOE epsilon 4/epsilon 4 genotype were recruited via local Auria Biobank (Turku, Finland). Recruitment of the project has been completed in July 2020 and 63 individuals were enrolled to three study groups (Group 1: APOE epsilon 4/epsilon 4, N = 19; Group 2: APOE epsilon 4/epsilon 3, N = 22; Group 3: APOE epsilon 3/epsilon 3, N = 22). At baseline, all participants will undergo positron emission tomography imaging with tracers targeted against A beta deposition (C-11-PIB), activated glia (C-11-PK11195) and synaptic vesicle glycoprotein 2A (C-11-UCB-J), two brain magnetic resonance imaging scans, and extensive cognitive testing. In addition, blood samples are collected for various laboratory measurements and blood biomarker analysis and cerebrospinal fluid samples are collected from a subset of participants based on additional voluntary informed consent. To evaluate the predictive value of the early neuroimaging findings, neuropsychological evaluation and blood biomarker measurements will be repeated after a 4-year follow-up period.& nbsp;Discussion:& nbsp;Results of the ASIC-E4 project will bridge the gap related to limited knowledge of the synaptic and inflammatory changes and their association with each other and A beta in "at-risk " individuals. Thorough in vivo characterization of the biomarker profiles in this population will produce valuable information for diagnostic purposes and future drug development, where the field has already started to look beyond A beta.
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| 6. |
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| 7. |
- Aarnio, H., et al.
(författare)
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Photoinduced absorption in an alternating polyfluorene copolymer for photovoltaic applications
- 2006
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Ingår i: Chemical Physics. ; 321:1-2, s. 127-132
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Tidskriftsartikel (refereegranskat)abstract
- The authors present a detailed study of a novel alternating polyfluorene copolymer, poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3-benzo-thiadiazole)], and its blends with the fullerene deriv. [6,6]-phenyl-C61-butyric acid Me ester, using continuous wave photoinduced absorption (PA) techniques. The authors also present the use of phase information from the PA measurements for estg. the no. of different photoexcitation types present in the PA spectra as well as their lifetimes. In all blends the PA spectra show a broad high-energy PA band ranging from .apprx.1 to 2 eV as well as a low-energy band at .apprx.0.35 eV. The authors find two kinds of excitations present at 80 DegK, polarons showing dispersive recombination with lifetimes of roughly a millisecond, and a 2nd kind of photoexcitation tentatively assigned to coulombically bound intrachain polaron pairs showing practically nondispersive recombination with a lifetime of .apprx.20 ms. [on SciFinder (R)]
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| 8. |
- Aarnio, K., et al.
(författare)
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Cardiovascular events after ischemic stroke in young adults: A prospective follow-up study
- 2016
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 86:20, s. 1872-1879
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Tidskriftsartikel (refereegranskat)abstract
- Objectives:To study the long-term risk of recurrent cardiac, arterial, and venous events in young stroke patients, and whether these risks differed between etiologic subgroups.Methods:The study population comprised 970 patients aged 15-49 years from the Helsinki Young Stroke Registry (HYSR) who had an ischemic stroke in 1994-2007. We obtained follow-up data until 2012 from the Finnish Care Register and Statistics Finland. Cumulative 15-year risks were analyzed with life tables, whereas relative risks and corresponding confidence intervals (CI) were based on hazard ratios (HR) from Cox regression analyses.Results:There were 283 (29.2%) patients with a cardiovascular event during the median follow-up of 10.1 years (range 0.1-18.0). Cumulative 15-year risk for venous events was 3.9%. Cumulative 15-year incidence rate for composite vascular events was 34.0 (95% CI 30.1-38.2) per 1,000 person-years. When adjusted for age and sex, patients with an index stroke caused by high-risk sources of cardioembolism had the highest HR for any subsequent cardiovascular events (3.7; 95% CI 2.6-5.4), whereas the large-artery atherosclerosis group had the highest HR (2.7; 95% CI 1.6-4.6) for recurrent stroke compared with patients with stroke of undetermined etiology.Conclusions:The risk for future cardiovascular events after ischemic stroke in young adults remains high for years after the index stroke, in particular when the index stroke is caused by high-risk sources of cardioembolism or large-artery atherosclerosis.
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| 9. |
- Allaouat, S, et al.
(författare)
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Long-term exposure to ambient fine particulate matter originating from traffic and residential wood combustion and the prevalence of depression
- 2021
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Ingår i: Journal of epidemiology and community health. - : BMJ. - 1470-2738 .- 0143-005X. ; 75:11, s. 1111-1116
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution has been suggested to be associated with depression. However, current evidence is conflicting, and no study has considered different sources of ambient particulate matter with an aerodynamic diameter below 2.5 µm (PM2.5). We evaluated the associations of long-term exposure to PM2.5 from road traffic and residential wood combustion with the prevalence of depression in the Helsinki region, Finland.MethodsWe conducted a cross-sectional analysis based on the Helsinki Capital Region Environmental Health Survey 2015–2016 (N=5895). Modelled long-term outdoor concentrations of PM2.5 were evaluated using high-resolution emission and dispersion modelling on an urban scale and linked to the home addresses of study participants. The outcome was self-reported doctor-diagnosed or treated depression. We applied logistic regression and calculated the OR for 1 μg/m3 increase in PM2.5, with 95% CI. Models were adjusted for potential confounders, including traffic noise and urban green space.ResultsOf the participants, 377 reported to have been diagnosed or treated for depression by a doctor. Long-term exposure to PM2.5 from road traffic (OR=1.23, 95% CI 0.86 to 1.73; n=5895) or residential wood combustion (OR=0.78, 95% CI 0.43 to 1.41; n=5895) was not associated with the prevalence of depression. The estimates for PM2.5 from road traffic were elevated, but statistically non-significant, for non-smokers (OR=1.38, 95% CI 0.94 to 2.01; n=4716).ConclusionsWe found no convincing evidence of an effect of long-term exposure to PM2.5 from road traffic or residential wood combustion on depression.
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