| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
- Broman, J., et al.
(författare)
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Long-term risk of recurrent vascular events and mortality in young stroke patients: Insights from a multicenter study
- 2023
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Ingår i: European Journal of Neurology. - 1351-5101. ; 30:9, s. 2675-2683
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although the incidence of stroke in the young is rising, data on long-term outcomes in these patients are scarce. We thus aimed to investigate the long-term risk of recurrent vascular events and mortality in a multicenter study. Methods: We followed 396 consecutive patients aged 18-55 years with ischemic stroke (IS) or transient ischemic attack (TIA) enrolled in three European centers during the period 2007-2010. A detailed outpatient clinical follow-up assessment was performed between 2018 and 2020. When an in-person follow- -up visit was not possible, outcome events were assessed using electronic records and registry data. Results: During a median follow-up of 11.8 (IQR 10.4-12.7) years, 89 (22.5%) patients experienced any recurrent vascular event, 62 (15.7%) had any cerebrovascular event, 34 (8.6%) had other vascular events, and 27 (6.8%) patients died. Cumulative 10-year incidence rate per 1000 person-years was 21.6 (95% CI 17.1-26.9) for any recurrent vascular event and 14.9 (95% CI 11.3-19.3) for any cerebrovascular event. The prevalence of cardiovascular risk factors increased over time, and 22 (13.5%) patients lacked any secondary preventive medication at the in-person follow-up. After adjustment for demographics and comorbidities, atrial fibrillation at baseline was found to be significantly associated with recurrent vascular events. Conclusions: This multicenter study shows a considerable risk of recurrent vascular events in young IS and TIA patients. Further studies should investigate whether detailed individual risk assessment, modern secondary preventive strategies, and better patient adherence may reduce recurrence risk.
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| 8. |
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| 9. |
- Kivioja, R., et al.
(författare)
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Risk factors for early-onset ischemic stroke: A case-control study
- 2018
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Ingår i: Journal of the American Heart Association. - 2047-9980. ; 7:21
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Tidskriftsartikel (refereegranskat)abstract
- Background-Recent studies have shown an increasing prevalence of vascular risk factors in young adults with ischemic stroke (IS). However, the strength of the association between all vascular risk factors and early-onset IS has not been fully established. Methods and Results-We compared 961 patients with a first-ever IS at 25 to 49 years to 1403 frequency-matched stroke-free controls from a population-based cohort study (FINRISK). Assessed risk factors included an active malignancy, atrial fibrillation, cardiovascular disease, current smoking status, a family history of stroke, high low-density lipoprotein cholesterol, high triglycerides, low high-density lipoprotein cholesterol, hypertension, and type 1 and type 2 diabetes mellitus. We performed subgroup analyses based on age, sex, and IS etiology. In a fully adjusted multivariable logistic regression analysis, significant risk factors for IS consisted of atrial fibrillation (odds ratio [OR], 10.43; 95% confidence interval [CI], 2.33–46.77], cardiovascular disease (OR, 8.01; 95% CI, 3.09–20.78), type 1 diabetes mellitus (OR, 6.72; 95% CI, 3.15–14.33), type 2 diabetes mellitus (OR, 2.31; 95% CI, 1.35–3.95), low high-density lipoprotein cholesterol (OR, 1.81; 95% CI, 1.37–2.40), current smoking status (OR, 1.81; 95% CI, 1.50–2.17), hypertension (OR, 1.43; 95% CI, 1.17–1.75), and a family history of stroke (OR, 1.37; 95% CI, 1.04–1.82). High low-density lipoprotein cholesterol exhibited an inverse association with IS. In the subgroup analyses, the most consistent associations appeared for current smoking status and type 1 diabetes mellitus. Conclusions-Our study establishes the associations between 11 vascular risk factors and early-onset IS, among which atrial fibrillation, cardiovascular disease, and both type 1 and 2 diabetes mellitus in particular showed strong associations. © 2018 The Authors.
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| 10. |
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| 11. |
- Westerling, M., et al.
(författare)
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Photoexcitation dynamics in an alternating polyfluorene copolymer
- 2007
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Ingår i: Phys. Rev. B: Condens. Matter Mater. Phys. FIELD Full Journal Title:Physical Review B: Condensed Matter and Materials Physics. ; 75:22
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Tidskriftsartikel (refereegranskat)abstract
- The authors used transient photoinduced absorption on femtosecond to nanosecond time scales as well as delayed fluorescence up to microseconds to study the photogeneration and recombination of charges in thin films of the alternating polyfluorene copolymer poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]. The authors interpret the results using a coupled rate equation model and find that the authors can fit all exptl. results with a single set of parameters. The model includes prompt (
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