| 1. |
- Al-Rubaei, Ahmed, et al.
(author)
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Long-term hydraulic and treatment performance of a 19-year old constructed stormwater wetland : Finally maturated or in need of maintenance?
- 2016
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In: Ecological Engineering. - : Elsevier BV. - 0925-8574 .- 1872-6992. ; 95, s. 73-82
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Journal article (peer-reviewed)abstract
- Constructed stormwater wetlands (CSWs) are a commonly used measure for stormwater retention and quality treatment. However, although questions have been raised about the long-term performance of CSWs, only a few studies have targeted this issue and none have evaluated the performance of CSWs more than approximately 5–10 years old. Further, most studies have not examined the development of the long-term performance of CSWs but delivered a snapshot at a certain point of time. The present study investigated the performance of a 19-year-old CSW in Växjö, Sweden, treating stormwater from a 320-ha urban catchment. Besides removal of sediment from the CSW’s forebay, no other maintenance had been conducted. However, regular inspections had been performed. The results of the present sampling campaign were compared to two existing datasets collected at the same CSW after three years of operation in 1997 and nine years of operation in 2003. The CSW was found to provide efficient peak flow reduction and, depending on the event characteristics, also volume reduction. It still treated stormwater effectively: removal of Cd, Cu, Pb, Zn, TSS and TP event mean concentrations were between 89 and 96%, whereas mean concentrations of TN were reduced by 59%. The load removal efficiencies were even higher. Comparative analysis of the three monitoring periods based on the load removal efficiency revealed that the CSW, despite the lack of maintenance, performed more efficiently and stably for most pollutants compared to when newly constructed. This underlines the importance of the establishment and maturation of constructed wetland systems. Overall, the results showed that CSWs are resilient systems, which if designed well and regularly inspected to prevent major issues, can work efficiently for at least two decades.
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| 2. |
- Al-Rubaei, Ahmed, et al.
(author)
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Long-term hydraulic performance of stormwater infiltration systems : a field survey
- 2013
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In: NOVATECH 2013.
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Conference paper (peer-reviewed)abstract
- This paper examined the factors influencing the long-term hydraulic performance of some stormwater infiltration systems (swale and two types of permeable pavements) in Växjö, southern Sweden. The infiltration capacities of 9 permeable pavements and 2 swales sites, all with different ages ranging from 1 year to 14 years, were measured using replicate double ring infiltrometers. The sites were either constructed of swale (2), interlocking concrete pavers (ICP) filled with gravel (2), concrete grid pavers (CGP) filled with gravel (3), or concrete grid pavers (CGP) filled with grass (4). The results of this study showed that the long-term behaviour of the infiltration capacity relies largely on the type and age of the system and the type of joint filling (gravel and grass). Furthermore, the study showed that the 11 year old concrete grid pavers filled with grass had the highest infiltration capacity (4.80 + 2.46 mm/min), whilst the 9 and 14 year old swales had the lowest infiltration capacity (0.10 + 0.00 mm/min).
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| 3. |
- Al-Rubaei, Ahmed Mohammed, et al.
(author)
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Effectiveness of a 19-Year Old Combined Pond-Wetland System in Removing Particulate and Dissolved Pollutants
- 2017
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In: Wetlands (Wilmington, N.C.). - : Springer. - 0277-5212 .- 1943-6246. ; 37:3, s. 485-496
-
Journal article (peer-reviewed)abstract
- This study monitored the stormwater runoff quantity and quality treatment performance of a 6.8 ha 19-year old combined pond-wetland system, located in south Sweden, over one year. The mean volume reductions for 53 storm events for the pond and wetland were 40% and 28%, respectively, while the mean flow reductions were 60% and 76%, respectively. Pollutant concentrations in the influent to the wetland were highly variable. The pond-wetland system could efficiently remove an average of 91%, 80%, 94%, 91%, 83% and 92% of TSS, TP, particulate Cd, Cu, Pb, and Zn, respectively, whereas the removal of particulate and dissolved Ni was highly variable with an average of 67% ± 62% and −5% ± 41%, respectively. The removal of TN, NH4-N and NO3 + NO2-N was highly variable with an average of 45% ± 27%, 12% ± 96% and 45% ± 43%, respectively. These removal percentages are high in comparison to other studies and underline that relatively old systems can also provide efficient treatment. Although the pond accounted for a substantial reduction of pollutant concentration, the wetland significantly enhanced both the treatment performance and the peak flow reduction. This underlines that a combined pond/wetland system is a more beneficial solution than a pond only. The pollutant removal efficiency was significantly influenced by some factors including Antecedent Dry Days, seasonal variations, air temperature, retention times, rainfall depth and duration, and peak rainfall intensity.
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| 4. |
- Al-Rubaei, Ahmed Mohammed, et al.
(author)
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Long-Term Treatment Efficiency of a Constructed Stormwater Wetland: Preliminary Results
- 2014
-
Conference paper (peer-reviewed)abstract
- Constructed stormwater wetlands (CSWs) are commonly used in Sweden and worldwide because of their high efficiency in urban stormwater management. However, questions have been raised about the long-term performance of CSWs. This study investigated the performance of a 19-year-old constructed wetland, which was designed to treat the stormwater from a 320-ha catchment located in the city of Växjö, southern Sweden. The system has not been maintained since its construction in 1994. The results of the present study were compared with results obtained from a previous study conducted by Växjö Municipality in 1997. The results showed that the CSW significantly reduced peak flows by 72%. High concentration reductions were found for Cd, Cr, Cu, Zn, Pb, TSS and TP (90, 89, 91, 90, 96, 96 and 86%, respectively). TN concentrations were reduced by 61%. The results indicated that lack of maintenance had no effect on the performance of wetland system during this long period of operation (19 years). In contrast, especially the removal of Cu and nitrogen was enhanced compared to 1997, which may be due to maturing of the system. The results show that CSWs are resilient systems, which (provided that design is sufficient) can work efficiently for at least two decades.
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| 5. |
- Andersen, Malin, 1977-, et al.
(author)
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In silico detection of sequence variations modifying transcriptional regulation
- 2008
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In: PloS Computational Biology. - : Public Library of Science (PLoS). - 1553-734X .- 1553-7358. ; 4:1, s. e5-
-
Journal article (peer-reviewed)abstract
- Identification of functional genetic variation associated with increased susceptibility to complex diseases can elucidate genes and underlying biochemical mechanisms linked to disease onset and progression. For genes linked to genetic diseases, most identified causal mutations alter an encoded protein sequence. Technological advances for measuring RNA abundance suggest that a significant number of undiscovered causal mutations may alter the regulation of gene transcription. However, it remains a challenge to separate causal genetic variations from linked neutral variations. Here we present an in silico driven approach to identify possible genetic variation in regulatory sequences. The approach combines phylogenetic footprinting and transcription factor binding site prediction to identify variation in candidate cis-regulatory elements. The bioinformatics approach has been tested on a set of SNPs that are reported to have a regulatory function, as well as background SNPs. In the absence of additional information about an analyzed gene, the poor specificity of binding site prediction is prohibitive to its application. However, when additional data is available that can give guidance on which transcription factor is involved in the regulation of the gene, the in silico binding site prediction improves the selection of candidate regulatory polymorphisms for further analyses. The bioinformatics software generated for the analysis has been implemented as a Web-based application system entitled RAVEN ( regulatory analysis of variation in enhancers). The RAVEN system is available at http://www.cisreg.ca for all researchers interested in the detection and characterization of regulatory sequence variation.
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| 6. |
- Araghi, Marzieh, et al.
(author)
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Use of moist oral snuff (snus) and pancreatic cancer : Pooled analysis of nine prospective observational studies
- 2017
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 141:4, s. 687-693
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Journal article (peer-reviewed)abstract
- While smoking is a well-established risk factor for pancreatic cancer, the effect of smokeless tobacco is less well understood. We used pooled individual data from the Swedish Collaboration on Health Effects of Snus Use to assess the association between Swedish snus use and the risk of pancreatic cancer. A total of 424,152 male participants from nine cohort studies were followed up for risk of pancreatic cancer through linkage to health registers. We used shared frailty models with random effects at the study level, to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for confounding factors. During 9,276,054 person-years of observation, 1,447 men developed pancreatic cancer. Compared to never-snus use, current snus use was not associated with risk of pancreatic cancer (HR 0.96, 95% CI 0.83-1.11) after adjustment for smoking. Swedish snus use does not appear to be implicated in the development of pancreatic cancer in men. Tobacco smoke constituents other than nicotine or its metabolites may account for the relationship between smoking and pancreatic cancer. What's new? While smoking is a well-established risk factor for pancreatic cancer, the effect of smokeless tobacco is less well understood. Smokeless tobacco like snus yields lower exposure to tobacco carcinogens compared with smoking, because it does not undergo combustion, but delivers an equivalent dose of nicotine. Using pooled individual data from the Swedish Collaboration on Health Effects of Snus Use, here the authors show that Swedish snus use does not appear to be implicated in the development of pancreatic cancer in men. Tobacco smoke constituents other than nicotine or its metabolites may account for the relationship between smoking and pancreatic cancer.
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| 7. |
- Ayob, Mohd Nasir, et al.
(author)
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Small-Scale Renewable Energy Converters for Battery Charging
- 2018
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In: Journal of Marine Science and Engineering. - : MDPI. - 2077-1312. ; 6:1
-
Journal article (peer-reviewed)abstract
- This paper presents two wave energy concepts for small-scale electricity generation. In the presented case, these concepts are installed on the buoy of a heaving, point-absorbing wave energy converter (WEC) for large scale electricity production. In the studied WEC, developed by Uppsala University, small-scale electricity generation in the buoy is needed to power a tidal compensating system designed to increase the performance of the WEC in areas with high tides. The two considered and modeled concepts are an oscillating water column (OWC) and a heaving point absorber. The results indicate that the OWC is too small for the task and does not produce enough energy. On the other hand, the results show that a hybrid system composed of a small heaving point absorber combined with a solar energy system would be able to provide a requested minimum power of around 37.7W on average year around. The WEC and solar panel complement each other, as the WEC produces enough energy by itself during wintertime (but not in the summer), while the solar panel produces enough energy in the summer (but not in the winter).
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| 8. |
- Bartholdson, Örjan, et al.
(author)
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Does paying pay off? : paying for ecosystem services and exploring alternative possibilities
- 2012
-
Reports (other academic/artistic)abstract
- The ongoing degradation of ecosystems threaten future food production and the international community thus urgently has to plan for how to secure fundamental life-support services for the future, so called ecosystem services (ES). Examples of such ES are climate regulation, nutrient cycles, fresh water provision, etc.This report is focused on two distinct strategies to make land users in tropical rainforest areas continue to provide ecosystem services. The first approach, Payment for Ecosystem Services (PES), is an economic instrument designed at global and national levels. Several PES schemes are currently implemented in a global context where increasing human demands for food, fibre and fuel are accelerating competition for land. The overall aim of the PES projects covered by this report is to lower the emission of green house gas on national and global levels and they are especially directed towards forest areas. The PES projects specify that specific rural groups are paid if they agree to protect, manage or restore the ecosystem service provisioning system within their forest territories. This report highlights that many PES initiatives are being implemented with a ‘conservation perspective’, rather than seeing ecosystem services as integrated with production and livelihoods. There are also alternative strategies to manage ecosystem services. In this report we put an emphasis on an approach where production and conservation are planned for within the same landscape and production systems. Many smallholders already integrate and maintain ecosystem services in their agricultural/forest production systems in a long-term perspective, while producing food, fibre and fuel for the households’ own consumption as well as for sale. In such a system, the local communities are totally dependent on the ecosystem services to re-generate conditions for their agricultural production and/or forest extraction. The focus in such farming-forestry systems, using little or no inputs, which are totally dependent on renewable resources, is on how to increase agricultural/forest production by supporting local ecosystem services, such as soil fertility and structure, pollination, micro climate, biological control of crop pests, etc. The ecosystem services functions, such as carbon sequestration, then emerge as a ‘by-product’ out of these production systems. Increased soil humus in the soil and biomass accumulation are other examples of such ‘by-products’. We want to illustrate potentials and challenges with the aforementioned two approaches to secure ecosystem provisions, and how they are articulated within their specific contexts. This report explores these two approaches by examining case-studies in tropical forest areas in Peru, Brazil, Tanzania and Vietnam, as well as the experiences of EU-designed PES schemes for subsidies/support so as to achieve environmental protection in Sweden.
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| 9. |
- Bay, Annika, et al.
(author)
-
Patient reported outcomes are associated with physical activity level in adults with congenital heart disease.
- 2017
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In: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 243, s. 174-179
-
Journal article (peer-reviewed)abstract
- BACKGROUND: In general, adults with congenital heart disease (CHD) have impaired exercise capacity, and approximately 50% do not reach current recommendations on physical activity. Herein we analysed factors associated with physical activity level (PAL) in adults with CHD by using patient-reported outcomes (PRO).METHODS: Patients with CHD (n=471) were randomly selected from the national register on CHD and categorized according to complexity of lesions - simple (n=172, 39.1±14.6years), moderate (n=212, 39±14.1years), and severe (n=87, 31.7±10.7years). Participants completed a standardized questionnaire measuring PRO-domains including PAL. Variables associated with PAL were tested in multivariate logistic regression.RESULTS: PAL was categorized into high (≥3 METs ≥2.5h/week, n=192) and low (≥3 METs <2.5h/week, n=279). Patients with low PAL were older (42.6 vs. 35.8years, p≤0.001), had more prescribed medications (51% vs. 39%, p=0.009), more symptoms (25% vs. 16%, p=0.02) and comorbidity (45% vs. 34% p=0.02). Patients with low PAL rated a lower quality of life (76.6 vs. 83.4, p<0.001), satisfaction with life (25.6 vs. 27.3, p=0.003), a lower Physical Component Summary score (PCS) (78.1 vs. 90.5, p<0.001) and Mental Component Summary score (MCS) (73.5 vs. 79.5, p<0.001). Complexity of heart lesion was not associated with PAL. The included PROs - separately tested in the model, together with age were associated with PAL.CONCLUSIONS: PCS and MCS are stronger associated with PAL than age and medical factors. The use of these PROs could therefore provide valuable information of benefit for individualized advice regarding physical activity to patients with CHD.
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| 10. |
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| 11. |
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| 12. |
- Carstensen, John, et al.
(author)
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How does comorbidity influence healthcare costs? A population-based cross-sectional study of depression, back pain and osteoarthritis
- 2012
-
In: BMJ Open. - : BMJ. - 2044-6055. ; 2, s. e000809-
-
Journal article (peer-reviewed)abstract
- Objectives To analyse how comorbidity among patients with back pain, depression and osteoarthritis influences healthcare costs per patient. A special focus was made on the distribution of costs for primary healthcare compared with specialist care, hospital care and drugs.Design Population-based cross-sectional study.Setting The County of Östergötland, Sweden.Patients Data on diagnoses and healthcare costs for all 266 354 individuals between 20 and 75 years of age, who were residents of the County of Östergötland, Sweden, in the year 2006, were extracted from the local healthcare register and the national register of drug prescriptions.Main outcome measures The effects of comorbidity on healthcare costs were estimated as interactions in regression models that also included age, sex, number of other health conditions and education.Results The largest diagnosed group was back pain (11 178 patients) followed by depression (7412 patients) and osteoarthritis (5174 patients). The largest comorbidity subgroup was the combination of back pain and depression (772 patients), followed by the combination of back pain and osteoarthritis (527 patients) and the combination of depression and osteoarthritis (206 patients). For patients having both a depression diagnosis and a back pain diagnosis, there was a significant negative interaction effect on total healthcare costs. The average healthcare costs among patients with depression and back pain was SEK 11 806 lower for a patient with both diagnoses. In this comorbidity group, there were tendencies of a positive interaction for general practitioner visits and negative interactions for all other visits and hospital days. Small or no interactions at all were seen between depression diagnoses and osteoarthritis diagnoses.Conclusions A small increase in primary healthcare visits in comorbid back pain and depression patients was accompanied with a substantial reduction in total healthcare costs and in hospital costs. Our results can be of value in analysing the cost effects of comorbidity and how the coordination of primary and secondary care may have an impact on healthcare costs.
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| 13. |
- Chronéer, Diana, et al.
(author)
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Born global in a heartbeat
- 2009
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In: Proceedings of the XX ISPIM Conference, Vienna, Austria, 21-24 June 2009.
-
Conference paper (peer-reviewed)abstract
- This paper aims to enhance the knowledge of business model development in the mobile service sector by exploring the underlying components of a business model for organizations within that industry. By drawing from business model literature combined with findings from a longitudinal case study of an iPhone application, a conceptual business model for mobile services was developed. Proposed model extends earlier frameworks by adding contingency aspects and the view of core resources into a dynamic business model. Findings from the study highlight the importance for application developers to have an overall resource strategy in order to support the sustainability of their business models. This is particularly important due to the rapid pace of change in the industry and the technology.
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| 14. |
- Crespo, Alejandro J., et al.
(author)
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On the state-of-the-art of CFD simulations for wave energy converters within the open-source numerical framework of DualSPHysics
- 2023
-
In: Proceedings of the 15th European Wave and Tidal Energy Conference, Bilbao, 3-7 September 2023. - : European Wave and Tidal Energy Conference.
-
Conference paper (peer-reviewed)abstract
- There are currently several types of devices capable of harnessing wave energy, exploiting a broad variety of physical transformation processes. These devices – known as Wave Energy Converters (WECs) – are developed to maximize their power output. However, there are still uncertainties about their response and survivability to loads induced by adverse environmental conditions, with a consequent increase of the Levelized Cost of Energy (LCOE), which prevents in fact their commercial diffusion. As evidenced by a large body of research, marine renewable energy devices need to have more robust design practices. To address this issue, we propose the CFD-based DualSPHysics toolbox as a support in the design stages. DualSPHysics is high-fidelity software inherently suited to numerically address most challenges posed by multiphysics simulations, which are required to reliably predict WEC response in situations well beyond operational conditions. It should be noted that WECs, generally, may be connected to the seabed and comprise mechanical systems named Power Take-Offs (PTO) used to convert the energy from waves into electricity or other usable energies. To reproduce these features, DualSPHysics benefits from coupling with the multiphysics library Project Chrono and the dynamic mooring model Moordyn+. In this work, the augmented DualSPHysics framework is utilised to simulate a range of very different types of WECs with a variety of elements, such as catenary connections, taut mooring lines, or linear and nonlinear PTO actuators. Version 5.2 of the open-source licensed code was recently released, making the numerical framework publicly available as one unit. This work aims to provide a numerical review of past applications, and to demonstrate how the same open-source code is able to simulate very different technologies.Specifically, this paper proposes routine modeling and validation procedures using the SPH-based solver DualSPHysics applied to five different WEC types: i) a moored point absorber (PA); ii) an oscillating wave surge converter (OWSC); iii) a floating OWSC (so called FOSWEC); iv) a wave energy hyperbaric converter (WEHC); and v) a multi-body attenuator (so called Multi-float M4). For each device listed above, we provide validation proof against physical model data for various components of the floater(s) and PTO related quantities, performed under specific sea conditions that aim to challenge their survivability. Within the scope of this research, we present the WEC response with respect to the degrees of freedom that really matter for each of the floatings due to hydrodynamic interactions (i.e., heave, surge, and pitch), along with quantities more intimately connected to the anchoring systems (e.g., line tension) or the mechanical apparatus (e.g., end-stopper force). The quality of the results, the discussion built upon them and the demonstrated solver exploitability to a wide range of WECs show that one software model can run all cases using the exact same methodology, which is of great value for the marine energy R&D community. Finally, we discuss future research objectives, which include the implementation of automation to apply open control systems and possible applications to subsets of WEC farm arrays and other floating energy harnessing devices.
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| 15. |
- Ek, Malin, et al.
(author)
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AXIN1 in Plasma or Serum Is a Potential New Biomarker for Endometriosis
- 2019
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 20:1
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Journal article (peer-reviewed)abstract
- Although endometriosis is considered an inflammatory disease, no reliable diagnostic biomarkers exist for use in clinical practice. The aim was to investigate the inflammatory profile in endometriosis using an exploratory approach of inflammation-related proteins. Patients with laparoscopy-verified endometriosis (N = 172), women with microscopic colitis (N = 50), healthy controls (N = 31), and age-matched controls from the general population (N = 100) were enrolled and questionnaires regarding socioeconomic factors, lifestyle habits, and medical history were completed. Sera from patients and healthy controls were analyzed for 92 inflammatory biomarkers using Proximity Extension Assay technology (PEA). Plasma AXIN1 levels were analyzed in patients with endometriosis and controls from the general population by ELISA. General linear model adjusted for age, Mann⁻Whitney U-test, and principal component analysis (PCA) were used for statistical calculations. Serum levels of AXIN1 and ST1A1 were increased in endometriosis compared with MC (p < 0.001) and healthy controls (p = 0.001), whereas CXCL9 levels were decreased. Plasma levels of AXIN1 were elevated in endometriosis compared with age-matched controls from the general population (30.0 (17.0⁻38.0) pg/mL vs. 19.5 (15.0⁻28.0) pg/mL, p < 0.001). PCA analysis identified four clusters of proteins, where one cluster differed between endometriosis and controls, with strong correlations for AXIN1 and ST1A1. Plasma/serum AXIN1 is an interesting biomarker to be further evaluated in endometriosis.
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| 16. |
- Engström, Anders, et al.
(author)
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Summary report of CALPHAD XLIX - Stockholm, Sweden, 2022
- 2023
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In: Calphad. - : Elsevier BV. - 0364-5916 .- 1873-2984. ; 80, s. 102528-
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Journal article (other academic/artistic)abstract
- The CALPHAD XLIX conference took place in Stockholm, Sweden, from May 22 to 27, 2022. 112 participants from 18 countries attended the conference. The scientific program included 69 oral presentations divided into 16 thematic topics and 27 posters.
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| 17. |
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| 18. |
- Engström, Jens, et al.
(author)
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Buoy geometry and its influence on survivability for apoint absorbing wave energy converter : Scaleexperiment and CFD simulations
- 2017
-
Conference paper (peer-reviewed)abstract
- For wave energy to be an economically viable energysource, the technology has to withstand power levelsduring storms that can be close to 50 times higher thanduring normal operating conditions, and withstandmany years of wear. The impact of high wave loads isstudied not only within the field of wave energy, buthas long been a subject of study for ships, platformsand other offshore structures.To model the force on the device under extreme and/orovertopping waves is a difficult task. Experiments areexpensive and difficult to implement, and numerical meth-ods are either very computationally demanding CFD-methods, or less accurate approximative methods. Inaddition, the performance and experienced forces during extreme waves are model dependent, and differentoffshore structures must be studied independently.Here, a 1:20 scale model of the Uppsala Universitypoint-absorber type wave energy converter (WEC) has been tested in extreme wave conditions at the COASTLaboratory Ocean Basin at Plymouth University. The WEC consists of a linear generator connected to a buoyat the sea surface, and performance of two differentbuoys is studied: a cylinder and cylinder with moon-pool. Two types of wave sets have been used: focusedwaves embedded into regular waves, and irregular waves. The focus of this paperis on comparing the performance of the two buoys, and on analysing the experimental data using a numerical model. A fully non-linear computational fluid dynamics(CFD) model based on OpenFOAM is presented and validated.
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| 19. |
- Engström, Jens, et al.
(author)
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Energy absorption from parks of point-absorbing wave energy converters in the Swedish exclusive economic zone
- 2020
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In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 8:1, s. 38-49
-
Journal article (peer-reviewed)abstract
- In a future energy system based on renewable energy sources, wave energy will most likely play a role due to its high energy potential and low intermittency. The power production from parks of wave energy converters of point absorber type has been extensively studied. This is also the case for the wave energy resource at many coastal areas around the globe. Wave energy has not yet reached a commercial level, and a large variety of technologies exist; therefore, an established method to calculate the technical potential for wave energy has still not been established. To estimate the technical potential of wave energy conversion, some approximations inevitably need to be taken due to the systems high complexity. In this study, a detailed mapping of the wave climate and simulation of large arrays of hydrodynamically cross‐coupled wave energy converters are combined to calculate the technical potential for wave energy conversion in the Swedish exclusive economic zone. A 16‐year wave data set distributed in a 1.1 km × 1.1 km grid is used to calculate the absorbed energy from a park of 200 generic point absorbers. The areas with best potential have an average annual energy absorption of 16 GWh for the selected wave energy park adapted to 1 km2 when using a constant damping, while the theoretical upper bound is 63 GWh for the same area.
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| 20. |
- Engström, Jens, et al.
(author)
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Offshore Measurements and Numerical Validation of the Mooring Forces on a 1:5 Scale Buoy
- 2023
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In: Journal of Marine Science and Engineering. - : MDPI. - 2077-1312. ; 11:1
-
Journal article (peer-reviewed)abstract
- Wave energy conversion is a renewable energy technology with a promising potential. Although it has been developed for more than 200 years, the technology is still far from mature. The survivability in extreme weather conditions is a key parameter halting its development. We present here results from two weeks of measurement with a force measurement buoy deployed at Uppsala University’s test site for wave energy research at the west coast of Sweden. The collected data have been used to investigate the reliability for two typical numerical wave energy converter models: one low fidelity model based on linear wave theory and one high fidelity Reynolds-Averaged Navier–Stokes model. The line force data is also analysed by extreme value theory using the peak-over-threshold method to study the statistical distribution of extreme forces and to predict the return period. The high fidelity model shows rather good agreement for the smaller waves, but overestimates the forces for larger waves, which can be attributed to uncertainties related to field measurements and numerical modelling uncertainties. The peak-over-threshold method gives a rather satisfying result for this data set. A significant deviation is observed in the measured force for sea states with the same significant wave height. This indicates that it will be difficult to calculate the force based on the significant wave height only, which points out the importance of more offshore experiments. © 2023 by the authors.
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| 21. |
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| 22. |
- Engström, Jens, et al.
(author)
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Performance of large arrays of point absorbing direct-driven wave energy converters
- 2013
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 114:20, s. 204502-
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Journal article (peer-reviewed)abstract
- Future commercial installation of wave energy plants using point absorber technology will require clusters of tens up to several hundred devices, in order to reach a viable electricity production. Interconnected devices also serve the purpose of power smoothing, which is especially important for devices using direct-driven power take off. The scope of this paper is to evaluate a method to optimize wave energy farms in terms of power production, economic viability and resources. In particular, the paper deals with the power variation in a large array of point-absorbing direct-driven wave energy converters, and the smoothing effect due to the number of devices and their hydrodynamic interactions. A few array geometries are compared and 34 sea states measured at the Lysekil research site at the Swedish west coast are used in the simulations. Potential linear flow theory are used with full hydrodynamic interactions between the buoys. It is shown that the variance in power production depends crucially on the geometry of the array and the number of interacting devices, but not significantly on the energy period of the waves.
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| 23. |
- Engström, Karolina, et al.
(author)
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Novel SMAD3 p.Arg386Thr genetic variant co-segregating with thoracic aortic aneurysm and dissection
- 2020
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In: Molecular Genetics & Genomic Medicine. - : John Wiley & Sons. - 2324-9269. ; 8:4
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Journal article (peer-reviewed)abstract
- Background: Pathogenic variants in the SMAD3 gene affecting the TGF-beta/SMAD3 signaling pathway with aortic vessel involvement cause Loeys-Dietz syndrome 3, also known as aneurysms-osteoarthritis syndrome.Methods: Description of clinical history of a family in Sweden using clinical data, DNA sequencing, bioinformatics, and pedigree analysis.Results: We report a novel SMAD3 variant, initially classified as a genetic variant of uncertain clinical significance (VUS), and later found to be co-segregating with aortic dissection in the family. The index patient presented with a dissecting aneurysm of the aorta including the ascending, descending, and abdominal parts. Genotype analysis revealed a heterozygous missense SMAD3 variant: NM_005902.3(SMAD3): c.11576G > C (p.Arg386Thr). The same variant was also identified in a 30 years old formalin-fixed paraffin-embedded block of tissue from a second cousin, who died at 26 years of age from a dissecting aneurysm of the aorta.Conclusion: A "variant of uncertain significance" according to the ACMG guidelines has always a scope for reappraisal. Genetic counselling to relatives, and the offering of surveillance service is important to families with aortic aneurysm disease. The report also highlight the potential use of FFPE analysis from deceased relatives to help in the interpretation of variants.
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| 24. |
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| 25. |
- Engström, My, 1977, et al.
(author)
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The meaning of awaiting bariatric surgery due to morbid obesity.
- 2011
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In: The open nursing journal. - : Bentham Science Publishers Ltd.. - 1874-4346. ; 5, s. 1-8
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Journal article (peer-reviewed)abstract
- The understanding of the association between the objective conditions of health and the subjective perceptions of morbidly obese patients appears to be poor. The use of objective indicators alone produces results totally unrelated to the feelings and experiences of the bariatric patients studied. No study has approached the bariatric patient from both an inside and a preoperative perspective.
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| 26. |
- Engström, Patrik, et al.
(author)
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Expansion of the Chlamydia trachomatis inclusion does not require bacterial replication
- 2015
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In: International Journal of Medical Microbiology. - : Elsevier BV. - 1438-4221 .- 1618-0607. ; 305:3, s. 378-382
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Journal article (peer-reviewed)abstract
- Chlamydia trachomatis replication takes place inside of a host cell, exclusively within a vacuole known as the inclusion. During an infection, the inclusion expands to accommodate the increasing numbers of C. trachomatis. However, whether inclusion expansion requires bacterial replication and/or de novo protein synthesis has not been previously investigated in detail. Therefore, using a chemical biology approach, we herein investigated C. trachomatis inclusion expansion under varying conditions in vitro. Under normal cell culture conditions, inclusion expansion correlated with C trachomatis replication. When bacterial replication was inhibited using KSK120: an inhibitor that targets C. trachomatis glucose metabolism, inclusions expanded even in the absence of bacterial replication. In contrast, when bacterial protein synthesis was inhibited using chloramphenicol, expansion of inclusions was blocked. Together, these data suggest that de novo protein synthesis is necessary, whereas bacterial replication is dispensable for C trachomatis inclusion expansion. (C) 2015 The Authors. Published by Elsevier GmbH.
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| 27. |
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| 28. |
- Eriksson, Elisabet, 1971-, et al.
(author)
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Job satisfaction and wellbeing among migrant care workers in nursing homes : An integrative review
- 2023
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In: Nursing Open. - : John Wiley & Sons. - 2054-1058. ; 10:6, s. 3486-3505
-
Research review (peer-reviewed)abstract
- Aim: To systematically analyse and synthesize studies investigating job satisfaction (including turnover and turnover intention) and wellbeing (physical, social and psychological including work stress, acculturation stress and sick leave) among migrant care workers in nursing homes.Design: An integrated review was conducted.Methods: Joanna Briggs Institute's manual guided the analysis of qualitative data (n = 31). Quantitative data (n = 17) were summarized and integrated with the qualitative findings.Results: Migrants described high job demands, limited control and social support, and stress possibly related to acculturation. Although, compared to natives (born in the country), inconsistent results were reported about wellbeing and job satisfaction, migrant care workers reported enjoying the relational aspects of work and feeling pride when providing care. A satisfying work environment for migrant care workers enables them enjoying working in elderly care with pride.Public Contribution: Help managers to promote an inclusive working life in line with the United Nations Sustainable Development Goal number 8.
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| 29. |
- Flisberg, Per, et al.
(author)
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The effects of platelet transfusions evaluated using rotational thromboelastometry.
- 2009
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In: Anesthesia and Analgesia. - : Ovid Technologies (Wolters Kluwer Health). - 1526-7598 .- 0003-2999. ; 108:5, s. 1430-1432
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Journal article (peer-reviewed)abstract
- BACKGROUND: In this study, we assessed the immediate effects of platelet transfusion on whole blood coagulation. METHODS: Ten thrombocytopenic patients given a single unit platelet transfusion of 200-300 x 10(9) platelets had their coagulation status assessed before and immediately after transfusion using rotational thromboelastometry. RESULTS: Transfusion increased the median platelet count from 31.5 to 43.5 x 10(9)/L. Clot formation time decreased by 32% (P = 0.005), whereas maximum clot strength increased by 47% (P = 0.005). CONCLUSION: Statistically significant improvements in rotational thromboelastometry-measured parameters were observed in association with a mean increase of 12 x 109/L in platelet count after platelet transfusion in these patients.
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| 30. |
- Giannini, Gianmaria, et al.
(author)
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Wave Energy Converter Power Take-Off System Scaling and Physical Modelling
- 2020
-
In: Journal of Marine Science and Engineering. - : MDPI. - 2077-1312. ; 8:9
-
Journal article (peer-reviewed)abstract
- Absorbing wave power from oceans for producing a usable form of energy represents an attractive challenge, which for the most part concerns the development and integration, in a wave energy device, of a reliable, efficient and cost-effective power take-off mechanism. During the various stages of progress, for assessing a wave energy device, it is convenient to carry out experimental testing that, opportunely, takes into account the realistic behaviour of the power take-off mechanism at a small scale. To successfully replicate and assess the power take-off, good practices need to be implemented aiming to correctly scale and evaluate the power take-off mechanism and its behaviour. The present paper aims to explore and propose solutions that can be applied for reproducing and assessing the power take-off element during experimental studies, namely experimental set-ups enhancements, calibration practices, and error estimation methods. A series of recommendations on how to practically organize and carry out experiments were identified and three case studies are briefly covered. It was found that, despite specific options that can be strictly technology-dependent, various recommendations could be universally applicable.
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| 31. |
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| 32. |
- Giassi, Marianna, et al.
(author)
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Capturing the experimental behaviour of a point-absorber WEC by simplified numerical models
- 2020
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In: Journal of Fluids and Structures. - : Elsevier BV. - 0889-9746 .- 1095-8622. ; 99
-
Journal article (peer-reviewed)abstract
- The paper presents a wave basin experiment of a direct-driven point-absorber wave energy converter moving in six degrees of freedom. The goal of the work is to study the dynamics and energy absorption of the wave energy converter, and to verify under which conditions numerical models restricted to heave can capture the behaviour of a point-absorber moving in six degrees of freedom. Several regular and irregular long-crested waves and different damping values of the power take-off system have been tested. We collected data in terms of power output, device motion in six degrees of freedom and wave elevation at different points of the wave basin. A single-body numerical model in the frequency domain and a two-body model in the time domain are used in the study. Motion instabilities due to parametric resonance observed during the experiments are discussed and analysis of the buoy motion in terms of the Mathieu instability is also presented. Our results show that the simplified models can reproduce the body dynamics of the studied converter as long as the transverse non-linear instabilities are not excited, which typically is the case in irregular waves. The performance of the more complex time domain model is able to reproduce both the buoy and PTO dynamics, while the simpler frequency domain model can only reproduce the PTO dynamics for specific cases. Finally, we show that the two-body dynamics of the studied wave energy converter affects the power absorption significantly, and that common assumptions in the numerical models, such as stiff mooring line or that the float moves only in heave, may lead to incorrect predictions for certain sea states.
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| 33. |
- Giassi, Marianna, et al.
(author)
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Comparison of wave energy park layouts by experimental and numerical methods
- 2020
-
In: Journal of Marine Science and Engineering. - : MDPI AG. - 2077-1312. ; 8:10
-
Journal article (peer-reviewed)abstract
- An experimental campaign of arrays with direct-driven wave energy converters of point-absorbing type is presented. The arrays consist of six identical floats, moving in six degrees of freedom, and six rotating power take-off systems, based on the design developed at Uppsala University. The goals of the work were to study and compare the performances of three different array layouts under several regular and irregular long-crested waves, and in addition, to determine whether the numerical predictions of the best performing array layouts were confirmed by experimental data. The simulations were executed with a frequency domain model restricted to heave, which is a computationally fast approach that was merged into a genetic algorithm optimization routine and used to find optimal array configurations. The results show that good agreement between experiments and simulations is achieved when the test conditions do not induce phenomena of parametric resonance, slack line and wave breaking. Specific non-linear dynamics or extensive sway motion are not captured by the used model, and in such cases the simulation predictions are not accurate, but can nevertheless be used to get an estimate of the power output.
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| 34. |
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| 35. |
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| 36. |
- Gliga, Anda R., et al.
(author)
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Maternal exposure to cadmium during pregnancy is associated with changes in DNA methylation that are persistent at 9 years of age
- 2022
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In: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 163
-
Journal article (peer-reviewed)abstract
- Background: Cadmium (Cd) exposure during gestation has been associated with altered DNA methylation at birth, but it is not known if the changes in methylation persist into childhood. Objectives: To evaluate whether gestational Cd-related changes of DNA methylation persist from birth to 9 years of age. Methods: We studied mother–child dyads in a longitudinal cohort in rural Bangladesh. Cadmium concentrations in maternal blood (erythrocyte fraction; Ery-Cd) at gestational week 14 and in child urine (U-Cd, long-term exposure marker) at 9 years were measured using inductively coupled plasma mass spectrometry. The epigenome-wide DNA methylation was measured in mononuclear cells (PBMCs) prepared from cord blood and peripheral blood at 9 years in 71 children (hereafter referred to as the explorative group) by Infinium HumanMethylation450K BeadChip. Replication of one differentially methylated region (DMR; 9 CpG sites) was performed in PBMCs of 160 9-year-old children (validation group) by EpiTyper MALDI-TOF mass spectrometry. Results: The median maternal Ery-Cd concentration was 1.24 µg/kg (range 0.35, 4.55) in the explorative group and 0.83 µg/kg (0.08, 2.97) in the validation group. The median U-Cd concentration in the 9-year-old children was 0.26 µg/L (0.09, 1.06) in the explorative group and 0.32 µg/L (0.07, 1.33) in the validation group. In the explorative group, we identified ten DMRs, both in cord blood and in PBMCs at 9 years, that were associated with maternal Ery-Cd. Eight out of the ten DMRs were hypomethylated and three of the hypomethylated DMRs were located in the HLA region on chromosome 6. One of the DMRs (hypomethylated) in the HLA region (upstream of the zinc finger protein 57 homolog, ZFP57 gene) was replicated in the validation group, and we found that it was hypomethylated in relation to maternal Ery-Cd, but not child U-Cd. Conclusion: Gestational exposure to Cd appears to be associated with regional changes, especially hypomethylated, in DNA methylation that linger from birth up to prepubertal age.
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| 37. |
- Göteman, Malin, 1980-, et al.
(author)
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Advances and Challenges in Wave Energy Park Optimization : A Review
- 2020
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In: Frontiers in Energy Research. - : Frontiers Media SA. - 2296-598X. ; 8
-
Research review (peer-reviewed)abstract
- A commercial wave energy system will typically consist of many interacting wave energy converters installed in a park. The performance of the park depends on many parameters such as array layout and number of devices, and may be evaluated based on different measures such as energy absorption, electricity quality, or cost of the produced electricity. As wave energy is currently at the stage where several large-scale installations are being planned, optimizing the park performance is an active research area, with many important contributions in the past few years. Here, this research is reviewed, with a focus on identifying the current state of the art, analyzing how realistic, reliable, and relevant the methods and the results are, and outlining directions for future research.
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| 38. |
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| 39. |
- Göteman, Malin, 1980-, et al.
(author)
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Arrays of Point-Absorbing Wave Energy Converters in Short-Crested Irregular Waves
- 2018
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In: Energies. - : MDPI AG. - 1996-1073. ; 11:4
-
Journal article (peer-reviewed)abstract
- For most wave energy technology concepts, large-scale electricity production and cost-efficiency require that the devices are installed together in parks. The hydrodynamical interactions between the devices will affect the total performance of the park, and the optimization of the park layout and other park design parameters is a topic of active research. Most studies have considered wave energy parks in long-crested, unidirectional waves. However, real ocean waves can be short-crested, with waves propagating simultaneously in several directions, and some studies have indicated that the wave energy park performance might change in short-crested waves. Here, theory for short-crested waves is integrated in an analytical multiple scattering method, and used to evaluate wave energy park performance in irregular, short-crested waves with different number of wave directions and directional spreading parameters. The results show that the energy absorption is comparable to the situation in long-crested waves, but that the power fluctuations are significantly lower.
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| 40. |
- Göteman, Malin, 1980-, et al.
(author)
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Fast modeling of large wave energy farms using interaction distance cut-off
- 2015
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In: Energies. - : MDPI AG. - 1996-1073. ; 8:12, s. 13741-13757
-
Journal article (peer-reviewed)abstract
- In many wave energy concepts, power output in the MW range requires the simultaneous operation of many wave energy converters. In particular, this is true for small point-absorbers, where a wave energy farm may contain several hundred devices. The total performance of the farm is affected by the hydrodynamic interactions between the individual devices, and reliable tools that can model full farms are needed to study power output and find optimal design parameters. This paper presents a novel method to model the hydrodynamic interactions and power output of very large wave energy farms. The method is based on analytical multiple scattering theory and uses time series of irregular wave amplitudes to compute the instantaneous power of each device. An interaction distance cut-off is introduced to improve the computational cost with acceptable accuracy. As an application of the method, wave energy farms with over 100 devices are studied in the MW range using one month of wave data measured at an off-shore site.
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| 41. |
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| 42. |
- Göteman, Malin, 1980-, et al.
(author)
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Methods of reducing power fluctuations in wave energy parks
- 2014
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In: Journal of Renewable and Sustainable Energy. - : AIP Publishing. - 1941-7012. ; 6, s. 043103-
-
Journal article (peer-reviewed)abstract
- One of the major challenges in constructing effective and economically viable wave energy parks is to reduce the large fluctuations in power output. In this paper, we study different methods of reducing the fluctuations and improve the output power quality. The parameters studied include the number of devices, the separating distance between units, the global and local geometries of the array, sea state and incoming wave direction, and the impact of including buoys of different radii in an array. Our results show that, e. g., the fluctuations as well as power per device decrease strictly with the number of interacting units, when the separating distance is kept constant. However, including more devices in a park with fixed area will not necessarily result in lowered power fluctuations. We also show that varying the distance between units affects the power fluctuations to a much larger extent than it affects the magnitude of the absorbed power. The fluctuations are slightly lower in more realistic, randomized geometries where the buoys tend to drift slightly off their mean positions, and significantly lower in semi-circular geometries as opposed to rectangular geometries.
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| 43. |
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| 44. |
- Göteman, Malin, 1980-, et al.
(author)
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Optimizing wave energy parks with over 1000 interacting point-absorbers using an approximate analytical method
- 2015
-
In: International Journal of Marine Energy. - : Elsevier BV. - 2214-1669. ; 10, s. 113-126
-
Journal article (peer-reviewed)abstract
- Large arrays of wave energy converters of point-absorber type are studied using an approximate analytical model. The model is validated against a numerical method that takes into account full hydrodynamic interactions based on linear potential flow theory. The low computational cost of the analytical model enables parameter studies of parks in the MW range and includes up to over 1000 interacting devices. The model is actuated by irregular wave data obtained at the Swedish west coast. In particular, focus is on comparing park geometries and improving park configurations to minimize the power fluctuations.
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| 45. |
- Göteman, Malin, 1980-, et al.
(author)
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Resilience of wave energy farms using metocean dependent failure rates and repair operations
- 2023
-
In: Ocean Engineering. - : Elsevier. - 0029-8018 .- 1873-5258. ; 280
-
Journal article (peer-reviewed)abstract
- Emerging offshore renewable energy technologies are expected to become an important part of the futureenergy system, and reliability for these new technologies in different metocean scenarios must be guaranteed.This poses a challenge in extreme weather scenarios like storms, in particular for less mature technologiessuch as wave energy. Not only the offshore survivability must be controlled; the restoration after disruptiveevents and failures should be addressed and optimized. Offshore operations are costly and cannot be carriedout if the weather is too harsh, and the resulting downtime after failures may be financially devastating forprojects. In this paper, the resilience of large wave energy systems is studied with respect to wave conditions,metocean dependent failure rates, and weather windows available for offshore repair operations. A metocean-and time-dependent failure rate is derived based on a Weibull distribution, which is a novelty of the paper.The performance of the farm is assessed using the varying failure rates and metocean data at different offshoresites. Critical metocean thresholds for different offshore vessels are considered, and the resilience is quantifiedusing relevant measures such as unavailability and expected energy not supplied. The resilience analysis iscoupled to an economic assessment of the wave farm and different repair strategies. Our results show thatthe commonly used assumption of constant failure rates is seen to overestimate the annual energy productionthan when a more realistic varying failure rate is used. Two offshore sites are compared, and the availabilityis found to be higher at the calmer site. Most of the evaluated repair strategies cannot be considered to beeconomically justified, when compared to the cost of the energy not supplied.
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| 46. |
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| 47. |
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| 48. |
- Hallengren, Erik, et al.
(author)
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Genetic determinants of growth hormone and GH-related phenotypes
- 2017
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In: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 18, s. 1-9
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Higher fasting Growth Hormone (GH) has been associated with increased cardiovascular morbidity and mortality. Our objective was to find genetic determinants of fasting GH in order to facilitate future efforts of analyzing the association between fasting growth hormone and cardiovascular disease. A genome-wide association study (GWAS) was performed in a discovery cohort of 4134 persons (58% females; age 46-68 yrs), linking SNPs to fasting hs-GH. Fifteen SNPs were replicated in an independent cohort of 5262 persons (28.9% females; age 56-85 yrs). The best performing SNP was analyzed vs GH-related variables in a third independent cohort (n = 24,047; 61% females; age 44-73 yrs). A candidate gene approach searched for significant SNPs in the genes GH1 and GHR in the discovery cohort and was replicated as previously described.RESULTS: In the GWAS, the minor allele of rs7208736 was associated with lower GH in the discovery cohort (p = 5.15*10^-6) and the replication cohort (p = 0.005). The GH reducing allele was associated with lower BMI (P = 0.026) and waist (P = 0.021) in males only. In the candidate gene approach rs13153388 in the GHR-gene was associated with elevated GH-levels (P = 0.003) in the discovery cohort only and reduced height (P = 0.003).CONCLUSION: In the first GWAS ever for GH, we identify a novel locus on chromosome 17 associated with fasting GH levels, suggesting novel biological mechanisms behind GH secretion and GH-related traits. The candidate gene approach identified a genetic variant in the GHR, which was associated with an elevation of fasting hs-GH and lower height suggesting reduced GHR ligand sensitivity. Our findings need further replication.
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| 49. |
- Inghammar, Malin, et al.
(author)
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COPD and the risk of tuberculosis--a population-based cohort study.
- 2010
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:4
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Both chronic obstructive pulmonary disease (COPD) and tuberculosis (TB) primarily affect the lungs and are major causes of morbidity and mortality worldwide. COPD and TB have common risk factors such as smoking, low socioeconomic status and dysregulation of host defence functions. COPD is a prevalent co-morbid condition, especially in elderly with TB but in contrast to other diseases known to increase the risk of TB, relatively little is known about the specific relationship and impact from COPD on TB-incidence and mortality. METHODS AND FINDINGS: All individuals > or = 40 years of age, discharged with a diagnosis of COPD from Swedish hospitals 1987-2003 were identified in the Swedish Inpatient Register (n = 115,867). Records were linked to the Swedish Tuberculosis Register 1989-2007 and the relative risk of active TB in patients with COPD compared to control subjects randomly selected from the general population (matched for sex, year of birth and county of residence) was estimated using Cox regression. The analyses were stratified by year of birth, sex and county of residence and adjusted for immigration status, socioeconomic status (SES) and inpatient co-morbidities previously known to increase the risk of TB. COPD patients had a three-fold increased hazard ratio (HR) of developing active TB (HR 3.0 (95% confidence interval 2.4 to 4.0)) that was mainly dependent on an increased risk of pulmonary TB. In addition, logistic regression estimates showed that COPD patients who developed active TB had a two-fold increased risk of death from all causes within first year after the TB diagnosis compared to the general population control subjects with TB (OR 2.2, 95% confidence interval 1.2 to 4.1). CONCLUSIONS: This population-based study comprised of a large number of COPD patients shows that these patients have an increased risk of developing active TB compared to the general population. The results raise concerns that the increasing global burden of COPD will increase the incidence of active TB. The underlying contributory factors need to be disentangled in further studies.
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| 50. |
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