| 1. |
- Asghar, Naveed, 1983-, et al.
(författare)
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Flavivirus replicon-based novel vaccine candidates against Hepatitis viruses
- 2024
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Konferensbidrag (refereegranskat)abstract
- Chronic liver disease, resulting from Hepatitis B virus (HBV), Hepatitis D virus (HDV), or Hepatitis C virus (HCV) infections, contributes to a major health burden worldwide. Chronic infections with the hepatitis C virus (HCV) can be effectively cured by antivirals. However, the cured patients can be re-infected as they lack protective immune responses. In addition, the relatively high cost of the HCV treatment brings concerns about the accessibility, especially in the developing countries. Hence, there exists a need for cost effect vaccines with high efficiency to control and possibly eradicate Hepatitis viruses globally. The vaccine should induce either, or both, neutralizing antibodies and protective T cell responses. We have developed and utilized flavivirus replicons as delivery system to prime hepatitis-specific T cell responses. We generated subgenomic replicons of Tick-borne encephalitis virus (TBEV), Langat virus (LGTV), West-Nile virus (WNV), and Kunjin virus (KUNV) expressing either a fusion protein between the HCV NS3/4A and a stork hepatitis B virus core or a vaccine candidate gene of HB/DV. Transfection experiments showed that the antigen expression by KUNV and WNV replicons was several folds higher than the antigen expression of control DNA plasmid with CMV promoter. The immunogenicity of these flavivirus replicons was evaluated in mice. The KUNV replicon triggered a potent cellular immune response with respect to priming of HCV NS3/4A-specific T cells as determined by ELISpot, and polyfunctionality. In short, the newly developed KUNV replicon- based vaccine is an attractive candidate to provide protection against hepatitis viruses.
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| 2. |
- Gruzieva, Olena, et al.
(författare)
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Comparison of personal exposure to black carbon levels with fixed-site monitoring data and with dispersion modelling and the influence of activity patterns and environment
- 2024
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Ingår i: Journal of Exposure Science and Environmental Epidemiology. - 1559-0631 .- 1559-064X. ; 34:3, s. 538-545
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Tidskriftsartikel (refereegranskat)abstract
- Background: Short-term studies of health effects from ambient air pollution usually rely on fixed site monitoring data or spatio-temporal models for exposure characterization, but the relation to personal exposure is often not known.Objective: We aimed to explore this relation for black carbon (BC) in central Stockholm.Methods: Families (n = 46) with an infant, one parent working and one parent on parental leave, carried battery-operated BC instruments for 7 days. Routine BC monitoring data were obtained from rural background (RB) and urban background (UB) sites. Outdoor levels of BC at home and work were estimated in 24 h periods by dispersion modelling based on hourly real-time meteorological data, and statistical meteorological data representing annual mean conditions. Global radiation, air pressure, precipitation, temperature, and wind speed data were obtained from the UB station. All families lived in the city centre, within 4 km of the UB station.Results: The average level of 24 h personal BC was 425 (s.d. 181) ng/m3 for parents on leave, and 394 (s.d. 143) ng/m3 for working parents. The corresponding fixed-site monitoring observations were 148 (s.d. 139) at RB and 317 (s.d. 149) ng/m3 at UB. Modelled BC levels at home and at work were 493 (s.d. 228) and 331 (s.d. 173) ng/m3, respectively. UB, RB and air pressure explained only 21% of personal 24 h BC variability for parents on leave and 25% for working parents. Modelled home BC and observed air pressure explained 23% of personal BC, and adding modelled BC at work increased the explanation to 34% for the working parents.Impact: Short-term studies of health effects from ambient air pollution usually rely on fixed site monitoring data or spatio-temporal models for exposure characterization, but the relation to actual personal exposure is often not known. In this study we showed that both routine monitoring and modelled data explained less than 35% of variability in personal black carbon exposure. Hence, short-term health effects studies based on fixed site monitoring or spatio-temporal modelling are likely to be underpowered and subject to bias.
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| 3. |
- Gustafsson, Mats, 1966-, et al.
(författare)
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NORDUST II : Nordic Road Dust Project Phase II
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Road dust is an important source to airborne particles in the Nordic countries. It consists of wear products from road pavement, tyres, brakes, traction sand, salt and dust dragged in from adjacent unbound roads or deposited from nearby or long distance dust sources, like building sites and farmland. The cold climate in the Nordic countries enhances the formation of road dust compared to most European countries, since it promotes the use of studded tyres, which abrades the road surfaces, and winter maintenance where dust forming material is added to the road surfaces.The NORDUST II project has aimed to enhance knowledge about road dust emissions through extensive investigations, including laboratory and field studies, measurements, modeling, and future scenarios. An initial work package summarized current knowledge on mitigating road dust emissions. It found that dust binding solutions are most effective during acute dust episodes, while sweeping is beneficial on a seasonal basis. Preventive measures during autumn and winter can reduce airborne dust in spring. A core component of the project was experimental parameterization of processes in the NORTRIP emissions model. Studies revealed that vehicle weight and speed significantly influence particulate matter (PM) emissions, with heavier vehicles and higher speeds increasing emissions. The type of tire and road surface properties also play crucial roles.Experiments showed that winter sand is quickly crushed into finer fractions when driven over, but only a small portion of the sand mass is crushed. Coarse particles are removed more efficiently than finer particles at low speeds, but all particles are removed at speeds above 20 km/h. A field test in Linköping, Sweden, examined the removal of the dust binder CMA by traffic. Results indicated that the NORTRIP model could largely replicate the impact of traffic migration on CMA concentrations.
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| 4. |
- Larsson, Elin, 1996, et al.
(författare)
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Establishment of the Patient Acceptable Symptom State (PASS) for the Achilles Tendon Total Rupture Score in a Swedish Population
- 2024
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Ingår i: ORTHOPAEDIC JOURNAL OF SPORTS MEDICINE. - 2325-9671. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Background: As the use of patient-reported outcome measures (PROMs) is increasing in orthopaedic research, there is also a growing need for a standardized interpretation of these scores, such as the Patient Acceptable Symptom State (PASS), defined as the value beyond which patients consider themselves well. The Achilles tendon Total Rupture Score (ATRS) is the only PROM specific for Achilles tendon ruptures.Purpose: To establish the PASS for the ATRS in a Swedish population.Study Design: Cross-sectional study; Level of evidence, 3.Methods: Patients treated for an acute Achilles tendon rupture at a single institution in Sweden (injured between July 1, 2018, and December 31, 2020) were asked to participate in this study. The patients completed a questionnaire consisting of the ATRS and an anchor question: "How satisfied are you with the result of your treatment?" Receiver operating characteristic curve analysis was performed to calculate the PASS threshold for a positive response to the anchor question.Results: Of 516 eligible patients, 316 (61%) were included. The time from injury to completion of the questionnaire ranged from 12 to 27 months. The PASS threshold for the ATRS was found to be 75. The median ATRS of all patients was 80; 66% of patients reached an ATRS >= 75. Overall, 79% of patients were satisfied with the results of their treatment.Conclusion: The estimated PASS for the ATRS was 75 in the general Swedish population at 12 to 27 months after an acute Achilles tendon rupture.
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| 5. |
- Martin, Romain G., et al.
(författare)
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CF/PEEK skins assembly by induction welding for thermoplastic composite sandwich panels
- 2024
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Ingår i: Composites Part B. - : Elsevier Ltd. - 1359-8368 .- 1879-1069. ; 284
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Tidskriftsartikel (refereegranskat)abstract
- A method to assemble sandwich panels made of carbon fibre reinforced poly-ether-ether-ketone (CF/PEEK) facesheets and 3D-printed poly-ether-imide (PEI) honeycomb cores using induction welding is presented. Induction heating patterns inside CF/PEEK laminates of variable dimensions are first evaluated with a thermal camera and compared to a COMSOL Multiphysics model. Sandwich samples are then prepared by vacuum-assisted continuous induction welding under parameters selected from the modelling effort. Joining of sandwich panels made of CF/PEEK facesheets by induction welding under vacuum is demonstrated. Facesheets do not deconsolidate in the process and core crushing is avoided. Flatwise skin/core strength of the welded samples reaches up to 7 MPa, above reported performance for thermoset or thermoplastic composite sandwich panels. s
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| 6. |
- Martin, R. G., et al.
(författare)
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Manufacturing of thermoplastic composite sandwich panels using induction welding under vacuum
- 2024
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier Ltd. - 1359-835X .- 1878-5840. ; 182
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Tidskriftsartikel (refereegranskat)abstract
- A new method to manufacture thermoplastic composite sandwich panels is presented, making use of the induction welding process in which a magnetic susceptor generates the heat at the core/facesheet interface. This technique proposes a fast way to assemble thermoplastic sandwich structures without risking the deconsolidation of the composites skin. The welding pressure is obtained by applying vacuum over the sandwich panel. This vacuum induction welding method (Vac-IW) allows joining thermoplastic composite facesheets to a thermoplastic polymer core in a clean and non-contact manner. The feasibility of the method is demonstrated by preparing sandwich samples made of glass fibre reinforced polyetheretherketone (PEEK) skins and a 3D-printed polyetherimide (PEI) honeycomb core. A susceptor made of PEI and µm-sized nickel (Ni) particles is used to generate heat by magnetic hysteresis losses. The strength of the sandwich samples assembled by the Vac-IW method is evaluated by flatwise tensile (FWT) tests.
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| 7. |
- Zhang, Zhiguo, et al.
(författare)
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Improving 3-day deterministic air pollution forecasts using machine learning algorithms
- 2024
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 24:2, s. 807-851
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Tidskriftsartikel (refereegranskat)abstract
- As air pollution is regarded as the single largest environmental health risk in Europe it is important that communication to the public is up to date and accurate and provides means to avoid exposure to high air pollution levels. Long- and short-term exposure to outdoor air pollution is associated with increased risks of mortality and morbidity. Up-to-date information on present and coming days' air quality helps people avoid exposure during episodes with high levels of air pollution. Air quality forecasts can be based on deterministic dispersion modelling, but to be accurate this requires detailed information on future emissions, meteorological conditions and process-oriented dispersion modelling. In this paper, we apply different machine learning (ML) algorithms - random forest (RF), extreme gradient boosting (XGB), and long short-term memory (LSTM) - to improve 1, 2, and 3d deterministic forecasts of PM10, NOx, and O3 at different sites in Greater Stockholm, Sweden. It is shown that the deterministic forecasts can be significantly improved using the ML models but that the degree of improvement of the deterministic forecasts depends more on pollutant and site than on what ML algorithm is applied. Also, four feature importance methods, namely the mean decrease in impurity (MDI) method, permutation method, gradient-based method, and Shapley additive explanations (SHAP) method, are utilized to identify significant features that are common and robust across all models and methods for a pollutant. Deterministic forecasts of PM10 are improved by the ML models through the input of lagged measurements and Julian day partly reflecting seasonal variations not properly parameterized in the deterministic forecasts. A systematic discrepancy by the deterministic forecasts in the diurnal cycle of NOx is removed by the ML models considering lagged measurements and calendar data like hour and weekday, reflecting the influence of local traffic emissions. For O3 at the urban background site, the local photochemistry is not properly accounted for by the relatively coarse Copernicus Atmosphere Monitoring Service ensemble model (CAMS) used here for forecasting O3 but is compensated for using the ML models by taking lagged measurements into account. Through multiple repetitions of the training process, the resulting ML models achieved improvements for all sites and pollutants. For NOx at street canyon sites, mean squared error (MSE) decreased by up to 60%, and seven metrics, such as R2 and mean absolute percentage error (MAPE), exhibited consistent results. The prediction of PM10 is improved significantly at the urban background site, whereas the ML models at street sites have difficulty capturing more information. The prediction accuracy of O3 also modestly increased, with differences between metrics. Further work is needed to reduce deviations between model results and measurements for short periods with relatively high concentrations (peaks) at the street canyon sites. Such peaks can be due to a combination of non-typical emissions and unfavourable meteorological conditions, which are rather difficult to forecast. Furthermore, we show that general models trained using data from selected street sites can improve the deterministic forecasts of NOx at the station not involved in model training. For PM10 this was only possible using more complex LSTM models. An important aspect to consider when choosing ML algorithms is the computational requirements for training the models in the deployment of the system. Tree-based models (RF and XGB) require fewer computational resources and yield comparable performance in comparison to LSTM. Therefore, tree-based models are now implemented operationally in the forecasts of air pollution and health risks in Stockholm. Nevertheless, there is big potential to develop generic models using advanced ML to take into account not only local temporal variation but also spatial variation at different stations.
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| 8. |
- Zhou, Chunguang, et al.
(författare)
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Application of the magnetic tracer-tracking system in solids circulation measurement in a fluidized bed standpipe
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier B.V.. - 1385-8947 .- 1873-3212. ; 498
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the application of a magnetic tracer-tracking method in measuring solids circulation in a fluidized bed standpipe is investigated, due to its advantages of little intervention and cost efficiency, especially in pressurized systems. The method only needs to inject one small magnetic tracer to follow the main solid flow in the standpipe, therefore predicting particles’ real-time velocities. The measurement accuracy was thoroughly tested via comparing to conventional descending and accumulation methods. Main tracer properties, including tracer shape, density, and magnet core, were considered. Solids flow patterns in the standpipe were also regulated by changing orifice sizes and adding an inclined pipe, for the purpose of investigating the measurement accuracy in various conditions. The adverse effect of a narrow orifice on measurement was addressed via constructing a model that includes sand particles’ non-uniform velocity distribution across the standpipe cross-section. To interpret behaviors of tracers varied in size and density, a mathematical model was constructed to describe forces exerted on the tracer in the solids bed. The behaviors of the tracer immersed into the solids bed were also examined, providing an insight to that in a standpipe with continuous solids circulation. The solids bed density was also regulated by varying the mixture of olivine sand and carbonaceous particles at different proportions. The magnetic tracer-tracking method has been successfully validated, demonstrating good measurement accuracy of solids discharge flow rates in the standpipe, particularly avoiding cumbersome calibration. Moreover, the method can also determine sand waving and oscillated discharge behaviors, which might be related to solids’ stick–slip phenomena and is unlikely to be accurately determined using conventional descending and accumulation methods.
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| 9. |
- Zhou, Chunguang, 1986-, et al.
(författare)
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Application of the magnetic tracer-tracking system in solids circulation measurement in a fluidized bed standpipe
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 498
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the application of a magnetic tracer-tracking method in measuring solids circulation in a fluidized bed standpipe is investigated, due to its advantages of little intervention and cost efficiency, especially in pressurized systems. The method only needs to inject one small magnetic tracer to follow the main solid flow in the standpipe, therefore predicting particles' real-time velocities. The measurement accuracy was thoroughly tested via comparing to conventional descending and accumulation methods. Main tracer properties, including tracer shape, density, and magnet core, were considered. Solids flow patterns in the standpipe were also regulated by changing orifice sizes and adding an inclined pipe, for the purpose of investigating the measurement accuracy in various conditions. The adverse effect of a narrow orifice on measurement was addressed via constructing a model that includes sand particles' non-uniform velocity distribution across the standpipe crosssection. To interpret behaviors of tracers varied in size and density, a mathematical model was constructed to describe forces exerted on the tracer in the solids bed. The behaviors of the tracer immersed into the solids bed were also examined, providing an insight to that in a standpipe with continuous solids circulation. The solids bed density was also regulated by varying the mixture of olivine sand and carbonaceous particles at different proportions. The magnetic tracer-tracking method has been successfully validated, demonstrating good measurement accuracy of solids discharge flow rates in the standpipe, particularly avoiding cumbersome calibration. Moreover, the method can also determine sand waving and oscillated discharge behaviors, which might be related to solids' stick-slip phenomena and is unlikely to be accurately determined using conventional descending and accumulation methods.
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| 10. |
- Zhukova, Valentina, et al.
(författare)
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Free Space Microwave Sensing of Carbon Fiber Composites with Ferromagnetic Microwire Inclusions
- 2024
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Ingår i: IEEE Sensors Letters. - 2475-1472. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- We provide new experimental results on studies of composites with glass-coated ferromagnetic microwires aligned with the requirements of carbon composites. This work focuses on the free space microwave measurements of composites made from carbon fibers and ferromagnetic microwires inclusion focusing on the electromagnetic properties. We prepared several glass-coated microwires and selected Co-based microwires with optimum soft magnetic properties and high magnetoimpedance effect for composite fabrication. We observed that by using a low frequency modulating AC magnetic field parallel oriented to the ferromagnetic microwires allows us to distinguish the microwave signals originated from the ferromagnetic microwires inclusions from the response generated by the carbon fibers. The location of carbon fibers near magnetic microwires has a critical effect on the response signals (parameters S amplitude) obtained from such composites.
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