| 1. |
- Ericsson, Olle, et al.
(author)
-
Clinical validation of a novel automated cell-free DNA screening assay for trisomies 21, 13, and 18 in maternal plasma.
- 2019
-
In: Prenatal diagnosis. - : Wiley. - 1097-0223 .- 0197-3851. ; 39:11, s. 1011-1015
-
Journal article (peer-reviewed)abstract
- To evaluate clinical performance of a new automated cell-free (cf)DNA assay in maternal plasma screening for trisomies 21, 18, and 13, and to determine fetal sex.Maternal plasma samples from 1200 singleton pregnancies were analyzed with a new non-sequencing cfDNA method, which is based on imaging and counting specific chromosome targets. Reference outcomes were determined by either cytogenetic testing, of amniotic fluid or chorionic villi, or clinical examination of neonates.The samples examined included 158 fetal aneuploidies. Sensitivity was 100% (112/112) for trisomy 21, 89% (32/36) for trisomy 18, and 100% (10/10) for trisomy 13. The respective specificities were 100%, 99.5%, and 99.9%. There were five first pass failures (0.4%), all in unaffected pregnancies. Sex classification was performed on 979 of the samples and 99.6% (975/979) provided a concordant result.The new automated cfDNA assay has high sensitivity and specificity for trisomies 21, 18, and 13 and accurate classification of fetal sex, while maintaining a low failure rate. The study demonstrated that cfDNA testing can be simplified and automated to reduce cost and thereby enabling wider population-based screening.
|
|
| 2. |
- Gustafsson, Harald, et al.
(author)
-
Den dubbla blicken. En inledning
- 2007
-
In: Den dubbla blicken. Historia i de nordiska samhällena. - 9789185767007 ; , s. 7-26
-
Book chapter (other academic/artistic)
|
|
| 3. |
- Nyberg, Lena, 1979, et al.
(author)
-
A single-step competitive binding assay for mapping of single DNA molecules
- 2012
-
In: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 417:1, s. 404-408
-
Journal article (peer-reviewed)abstract
- Optical mapping of genomic DNA is of relevance for a plethora of applications such as scaffolding for sequencing and detection of structural variations as well as identification cif pathogens like bacteria and viruses. For future clinical applications it is desirable to have a fast and robust mapping method based on as few steps as possible. We here demonstrate a single-step method to obtain a DNA barcode that is directly visualized using nanofluidic devices and fluorescence microscopy. Using a mixture of YOYO-1, a bright DNA dye, and netropsin, a natural antibiotic with very high AT specificity, we obtain a DNA map with a fluorescence intensity profile along the DNA that reflects the underlying sequence. The netropsin binds to AT-tetrads and blocks these binding sites from YOYO-1 binding which results in lower fluorescence intensity from AT-rich regions of the DNA. We thus obtain a DNA barcode that is dark in AT-rich regions and bright in GC-rich regions with kilobasepair resolution. We demonstrate the versatility of the method by obtaining a barcode on DNA from the phage T4 that captures its circular permutation and agrees well with its known sequence.
|
|
| 4. |
- Persson, Fredrik, et al.
(author)
-
USING SIMULATION TO DETERMINE THE SAFETY STOCK LEVEL FOR INTERMITTENT DEMAND
- 2017
-
In: 2017 WINTER SIMULATION CONFERENCE (WSC). - : IEEE. - 9781538634288 ; , s. 3768-3779
-
Conference paper (peer-reviewed)abstract
- Safety stock calculations are difficult for products with intermittent demand, long production lead times, and high monetary values. Theoretically, forecasts can be used to reduce the need for safety stocks. A high precision forecast minimizes the need for safety stock and forecast evaluation measurements can be used to calculate the safety stock level. However, a more realistic determination of safety stock levels can he obtained by simulation. In this paper, simulation is used to model and experiment on a case with three end products in order to determine the relationship between safety stock levels and service levels. Also, a comparison is made with theoretically calculated safety stocks to see how well basic theoretical models for safety stock calculations fulfill the requirements of service level. The result is that simulation can provide a much more accurate determination of safety stock levels for intermittent demands than theoretical calculations.
|
|
| 5. |
- Alizadehheidari, Mohammadreza, 1987, et al.
(author)
-
Nanoconfined Circular and Linear DNA: Equilibrium Conformations and Unfolding Kinetics
- 2015
-
In: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 48:3, s. 871-878
-
Journal article (peer-reviewed)abstract
- Studies of circular DNA confined to nanofluidic channels are relevant both from a fundamental polymer-physics perspective and due to the importance of circular DNA molecules in vivo. We here observe the unfolding of confined DNA from the circular to linear configuration as a light-induced double-strand break occurs, characterize the dynamics, and compare the equilibrium conformational statistics of linear and circular configurations. This is important because it allows us to determine to what extent existing statistical theories describe the extension of confined circular DNA. We find that the ratio of the extensions of confined linear and circular DNA configurations increases as the buffer concentration decreases. The experimental results fall between theoretical predictions for the extended de Gennes regime at weaker confinement and the Odijk regime at stronger confinement. We show that it is possible to directly distinguish between circular and linear DNA molecules by measuring the emission intensity from the DNA. Finally, we determine the rate of unfolding and show that this rate is larger for more confined DNA, possibly reflecting the corresponding larger difference in entropy between the circular and linear configurations.
|
|
| 6. |
- Alizadehheidari, Mohammadreza, et al.
(author)
-
Nanoconfined Circular DNA
- 2014
-
In: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 106:2, s. 274A-274A
-
Journal article (other academic/artistic)abstract
- Nanofluidic channels have become a versatile tool to manipulate single DNA molecules. They allow investigation of confined single DNA molecules from a fundamental polymer physics perspective as well as for example in DNA barcoding techniques.
|
|
| 7. |
|
|
| 8. |
- Alizadehheidari, Mohammadreza, 1987, et al.
(author)
-
Unfolding of nanoconfined circular DNA
- 2015
-
In: BIOPHYSICAL JOURNAL. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 108:2 Supplement 1
-
Journal article (other academic/artistic)
|
|
| 9. |
- Asp, Michaela, et al.
(author)
-
Spatial detection of fetal marker genes expressed at low level in adult human heart tissue
- 2017
-
In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
-
Journal article (peer-reviewed)abstract
- Heart failure is a major health problem linked to poor quality of life and high mortality rates. Hence, novel biomarkers, such as fetal marker genes with low expression levels, could potentially differentiate disease states in order to improve therapy. In many studies on heart failure, cardiac biopsies have been analyzed as uniform pieces of tissue with bulk techniques, but this homogenization approach can mask medically relevant phenotypes occurring only in isolated parts of the tissue. This study examines such spatial variations within and between regions of cardiac biopsies. In contrast to standard RNA sequencing, this approach provides a spatially resolved transcriptome- and tissue-wide perspective of the adult human heart, and enables detection of fetal marker genes expressed by minor subpopulations of cells within the tissue. Analysis of patients with heart failure, with preserved ejection fraction, demonstrated spatially divergent expression of fetal genes in cardiac biopsies.
|
|
| 10. |
- Bergström, Göran, 1964, et al.
(author)
-
Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
- 2021
-
In: Circulation. - Philadelphia : American Heart Association. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
-
Journal article (peer-reviewed)abstract
- Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
|
|
| 11. |
- Bergström, Göran, et al.
(author)
-
Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
- 2021
-
In: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
-
Journal article (peer-reviewed)abstract
- Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
|
|
| 12. |
- Enlund, Fredrik, 1968, et al.
(author)
-
Molecular analyses of the candidate tumor suppressor gene, PLAGL1, in benign and malignant salivary gland tumors
- 2004
-
In: EUROPEAN JOURNAL OF ORAL SCIENCES. - : Wiley. - 0909-8836 .- 1600-0722. ; 112:6, s. 545-547
-
Journal article (peer-reviewed)abstract
- Deletions affecting the long arm of chromosome 6 are a characteristic feature of all major subtypes of malignant salivary gland tumors. Moreover, a subgroup of adenoid cystic carcinomas have t(6;9)(q23-25;p21-24) translocations with breakpoints located within the commonly deleted region. Here we have examined the possible involvement of the candidate tumor suppressor gene, PLAGL1, in these deletions and translocations. Northern blot and fluorescence in situ hybridization (FISH) analyses of a series of 27 salivary gland tumors revealed no significant changes in the gene expression or rearrangements of PLAGL1. FISH analysis also demonstrated that the 6q translocation breakpoint in adenoid cystic carcinomas with t(6;9) is proximal to the PLAGL1 locus. Collectively, these results indicate that PLAGL1 is not likely to be the major target gene of the 6q rearrangements in salivary gland tumors.
|
|
| 13. |
- Espinoza, Fredrik, et al.
(author)
-
Analysis of Open Answers to Survey Questions throughInteractive Clustering and Theme Extraction
- 2018
-
In: Proceedings of Conference on Human Information Interaction & Retrieval. - New York, New York, USA : ACM Digital Library. ; , s. 317-320
-
Conference paper (peer-reviewed)abstract
- This paper describes design principles for and the implementation of Gavagai Explorer—a new application which builds on interactive text clustering to extract themes from topically coherent text sets such as open text answers to surveys or questionnaires.An automated system is quick, consistent, and has full coverage over the study material. A system allows an analyst to analyze more answers in a given time period; provides the same initial results regardless of who does the analysis, reducing the risks of inter-rater discrepancy; and does not risk miss responses due to fatigue or boredom. These factors reduce the cost and increase the reliability of the service. The most important feature, however, is relieving the human analyst from the frustrating aspects of the coding task, freeing the effort to the central challenge of understanding themes. Gavagai Explorer is available on-line at http://explorer.gavagai.se
|
|
| 14. |
- Fornander, Louise Helena, et al.
(author)
-
Using Nanofluidic Channels to Probe the Dynamics of Rad51-DNA Filaments
- 2014
-
In: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 106:2, s. 692A-693A
-
Journal article (other academic/artistic)abstract
- Rad51 is a key protein involved in the strand exchange reaction, a reaction where genetic material is transferred between two homologous DNA strands. Strand exchange is initiated by Rad51 forming a helical filament around single-stranded DNA (ssDNA), and the strand exchange is thereafter executed with a homologous double-stranded DNA (dsDNA). The structure of Rad51-DNA filaments, and also the activity of the strand exchange reaction, is dependent on the presence of ATP and dications, where Ca2+ has been shown to promote a higher degree of strand exchange than Mg2+.
|
|
| 15. |
- Fornander, Louise, 1984, et al.
(author)
-
Visualizing the Nonhomogeneous Structure of RAD51 Filaments Using Nanofluidic Channels
- 2016
-
In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 32:33, s. 8403-8412
-
Journal article (peer-reviewed)abstract
- RAD51 is the key component of the homologous recombination pathway in eukaryotic cells and performs its task by forming filaments on DNA. In this study we investigate the physical properties of RAD51 filaments formed on DNA using nanofluidic channels and fluorescence microscopy. Contrary to the bacterial ortholog RecA, RAD51 forms inhomogeneous filaments on long DNA in vitro, consisting of several protein patches. We demonstrate that a permanent "kink" in the filament is formed where two patches meet if the stretch of naked DNA between the patches is short. The kinks are readily seen in the present microscopy approach but would be hard to identify using conventional single DNA molecule techniques where the DNA is more stretched. We also demonstrate that protein patches separated by longer stretches of bare DNA roll up on each other and this is visualized as transiently overlapping filaments. RAD51 filaments can be formed at several different conditions, varying the cation (Mg2+ or Ca2+), the DNA substrate (single-stranded or double-stranded), and the RAD51 concentration during filament nucleation, and we compare the properties of the different filaments formed. The results provide important information regarding the physical properties of RAD51 filaments but also demonstrate that nanofluidic channels are perfectly suited to study protein-DNA complexes.
|
|
| 16. |
- Friederich-Persson, Malou, et al.
(author)
-
Increased kidney metabolism as a pathway to kidney tissue hypoxia and damage : effects of triiodothyronine and dinitrophenol in normoglycemic rats.
- 2013
-
In: Advances in Experimental Medicine and Biology. - New York, NY : Springer-Verlag New York. - 0065-2598 .- 2214-8019. - 9781461474111 - 9781461472568 ; 789, s. 9-14
-
Journal article (peer-reviewed)abstract
- Intrarenal tissue hypoxia is an acknowledged common pathway to end-stage renal disease in clinically common conditions associated with development of chronic kidney disease, such as diabetes and hypertension. In diabetic kidneys, increased oxygen metabolism mediated by mitochondrial uncoupling results in decreased kidney oxygen tension (PO2) and contributes to the development of diabetic nephropathy. The present study investigated whether increased intrarenal oxygen metabolism per se can cause intrarenal tissue hypoxia and kidney damage, independently of confounding factors such as hyperglycemia and oxidative stress. Male Sprague-Dawley rats were untreated or treated with either triiodothyronine (T3, 10 g/kg bw/day, subcutaneously for 10 days) or the mitochondria uncoupler dinitrophenol (DNP, 30 mg/kg bw/day, oral gavage for 14 days), after which in vivo kidney function was evaluated in terms of glomerular filtration rate (GFR, inulin clearance), renal blood flow (RBF, Transonic, PAH clearance), cortical PO2 (Clark-type electrodes), kidney oxygen consumption (QO2), and proteinuria. Administration of both T3 and DNP increased kidney QO2 and decreased PO2 which resulted in proteinuria. However, GFR and RBF were unaltered by either treatment. The present study demonstrates that increased kidney metabolism per se can cause intrarenal tissue hypoxia which results in proteinuria. Increased kidney QO2 and concomitantly reduced PO2 may therefore be a mechanism for the development of chronic kidney disease and progression to end-stage renal disease.
|
|
| 17. |
|
|
| 18. |
- Fritzsche, Joachim, 1977, et al.
(author)
-
A lipid-based passivation scheme for nanofluidics
- 2012
-
In: 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2012; Okinawa; Japan; 28 October 2012 through 1 November 2012. - 9780979806452 ; , s. 1876-1878
-
Conference paper (peer-reviewed)abstract
- Stretching DNA in nanochannels allows for direct, visual studies of genomic DNA at the single molecule level. In order to facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We show long-term passivation of nanochannel surfaces to several relevant reagents and demonstrate that the performance of the lipid bilayer is significantly better compared to standard bovine serum albumin-based passivation. Moreover, we demonstrate how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation.
|
|
| 19. |
- Frykholm, Karolin, et al.
(author)
-
Probing Physical Properties of a DNA-Protein Complex Using Nanofluidic Channels
- 2014
-
In: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 106:2, s. 428A-429A
-
Journal article (other academic/artistic)abstract
- Nanofluidic channels have become an important tool to investigate single DNA molecules both from a fundamental polymer physics perspective as well as in e.g. optical mapping techniques. However, less effort has been made to study DNA-protein complexes. A main reason is that the extreme surface-to-volume ratio in the nanochannels causes most proteins to stick to the channel walls. We have recently overcome this problem by coating the channels with a lipid bilayer, thereby eliminating sticking.
|
|
| 20. |
- Frykholm, Karolin, 1977, et al.
(author)
-
Probing Physical Properties of a DNA- Protein Complex Using Nanofluidic Channels
- 2014
-
In: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 10:5, s. 884-887
-
Journal article (peer-reviewed)abstract
- A method to investigate physical properties of a DNA-protein complex in solution is demonstrated. By using tapered nanochannels and lipid passivation the persistence length of a RecA filament formed on double-stranded DNA is determined to 1.15 μm, in agreement with the literature, without attaching protein or DNA to any handles or surfaces.
|
|
| 21. |
- Gebert Persson, Sabine, et al.
(author)
-
Public and private networks in tourism – : barriers to network identity construction and commitmen
- 2019
-
Conference paper (peer-reviewed)abstract
- IntroductionDestinations all over the world encompass a broad range of stakeholders who all aspire to increase the tourism industry to accomplish regional development. At these destinations, there are many different stakeholders, who have mutual interest in a specific region, and there are different attempts to promote cooperation for joint efforts to attract visitors. Moreover, there is an increasing drive for municipalities to influence the tourism business as part of their regional development (Tillväxtverket, 2017).However, the aforementioned development of destinations has proven to involve competing interests between local, national and international stakeholders. Although private enterprises, the municipalities and on-governmental organizations, and residents have a common, or at least partly overlapping, interest in the development of a specific destination, competing interests will occasionally occur (c.f. Elbe et al., 2018). For instance, private businesses, like small local entrepreneurs, could be in direct competition with national or international corporations, despite the fact that they may have much to gain from joint marketing efforts (c.f. investment in a common brand). Similarly, public1organizations have a shared interest in the development of the tourism industry to increase tax revenues and job creation. However, municipalities have a greater responsibility for communities and its residents.As in many other sectors, public and private interactions are common within the tourism industry due to an overall reduction in public sector funding (Valente et al., 2015). Relationships between public and private actors are also set up to conjointly pool resources, share risks in the process of building, maintaining and developing public services (Keränen, 2017). Interactions between public-private actors have been acknowledged as important since these relationships enable firms to influence decisions within areas such as the public sector, rules and actions that can affect how the firm is perceived as legitimate or not (Hadjikhani, Lee, & Ghauri, 2008; Jansson, Saqib, & Sharma, 1995) but also as ways to develop new and existing resources. However, research has shown that uncertainty tends to be rather high in these relationships and the roles that the actors play are consequently dynamic and unclear. This in turn also affects how the actors perceive the cooperation between public and private actors (Keränen, 2017) and their commitment to these types of networks (Elbe et al., 2018). The sought after commitment would be enhanced if a mutual identity could be constituted; still the identity is established from how the stakeholders perceive their roles and relations to each other. So how could the identity of public actors merge with the identity of private actors to establish a mutual and common identity?Despite the apparent advantage to create a network to coordinate mutual, or at least overlapping, interests, it has proven to entail a number of difficult issues of which some will be addressed below. The combination of private and public stakeholders in one organization may have implications for its role and commitments (c.f. Elbe et al. 2009; 2018) i.e. it could influence the perceived identity construction of its constituents. The combination of public and private interests in the same organization could create tension; one perspective could have precedence over the other. For instance, if a publicly funded organization considers it to be its mission to only enhance businesses, there are stakeholder who could be overlooked, such as permanent residents, community services, and other lines of industry. Although the established networks are intended to work towards common goals, there may still be implicit and ambiguous goals, roles and identity formations.2The organizing of public and private interests in order to transform a place and its characteristics into a destination has proven to be a complex process. More research is needed in order to bring further clarity into factors affecting these types of relationships in terms of activities and resources (de Araujo and Bramwell, 2002) as well as how this affects the actors. Although there is a growing scholarly interest in public-private relationships, additional knowledge is needed on how the processes of these types of cooperation evolve (de Araujo and Bramwell, 2002). This is especially so in the context of created networks where the network is constructed rather than emerging and where the aim is to foster and manage activities, resource interactions and actor bonds.This paper sets out to further the understanding of interaction processes where public and private actors attempt to find ways to cooperate on a common issue. This is done by analyzing how the identity of a created network, consisting of public and private actors, develops over time. This paper focuses on explaining how a created network develops over time and why it evolves in the way it does. The purpose is to identify possible barriers to identity construction in a created network consisting of public and private actors. This is done through a case taking its point of departure in the decision of a major infrastructural investment in a destination in Sweden: the building of a new cruise quay on Gotland.Created public-private cooperation – previous research.Interactions between public-private actors have been acknowledged as important since these relationships enable firms to influence decisions within different areas such as the public sector, rules and actions (Keränen, 2017; Elbe et al., 2018) but also as ways to develop new and existing resources. These co-operations are encouraged by governments in many countries as interactions can facilitate the discussions and decisions related to how different activities evolve and are coordinated as well as how public resources are distributed. Moral responsibility and a way to recover citizens’ trust for politicians’ abilities to deliver on electoral pledge when resources are scarce has been emphasized as a reason for cooperation between public and private actors (Velotti, Botti & Vesci, 2012). In a tourism context, private-public cooperation can also increase the competitive advantage of destinations (Kotler et al., 1993).Over the last decades, a growing number of designated organizations for the coordination of tourist actors have been established using the concept of: Destination Management Organizations, DMO (c.f. Elbe et al. 2009). According to UNWTO (2018), the DMO’s3role should, “be to lead and coordinate activities under a coherent strategy in pursuit of this common goal.” The argument in research, and in practice, has been that these destination organizations can manage marketing and coordinate different actors from varying sectors in the society. Through this, it is assumed that the destination through facilitation of interactions among local actors and creation of networks can stimulate economic growth (Elbe et al., 2018). Hence, specific organizations are politically created to facilitate regional development. In addition, DMOs are proposed as a coalition of many organizations and interest although in practice, these organizations have proven to be composed in different ways, with varying performance (Tillväxtverket 2017). In order to understand the accomplishment the sought-after coordination of diverse stakeholder interests, a network approach has been suggested that encompasses inter-organizational relations (Elbe et al. 2018). The proposed network approach could take into account relations between organizations, not only limited to intra-organizational management models that do not encompass all stakeholders.Despite the numerous potential advantages of public-private interactions, they can be time- consuming and difficult as the participants come from different sectors and with deviating interests. Therefore, actors can perceive a risk that their power and influence may decrease. This can also lead to a lack of trust between the actors (de Araujo & Bramwell, 2002).Tensions and paradoxesInteraction between business actors are built around an economic rational. An assumption is that without economic incentives, interactions between business actors in networks will not come about (Håkansson, 1982; Finke et al., 2017). Different types of resources such as financial resources (capital), physical resources (time, technologies, people) and informational resources (knowledge) are exchanged and combined in new and unique ways through the interactions. Resources are through inherently dynamic and can always be used in new combinations within one relationship or in other relationships (Baraldi et al., 2012). An important condition and a factor influencing the interaction processes are the norms and perceptions of what constitutes the rules of the game. Through the interactions new norms for exchange can form and influence the continuation of the exchange. Whether to engage in the cooperation or not will be affected by previous experiences and expectations as expressed by Mousas and Ford (2009, p. 497): “Recurrent episodes are affected by the perceptions of the participants of their previous interactions and by their expectations of the future.” These exchange relationships, constitute the context in which interaction4processes between actors takes place (Easton & Håkansson, 1996; Håkansson & Ford, 2002; Håkansson & Waluszewski, 2002, 2007; Ritter, 2000).In tourist destinations, many of the resources used to attract tourists are public and common goods. The question of who owns these common goods is not always clear. Beaches, lakes, museums, culture heritage buildings are all resources that can attract tourists but that are public. Exchange relationships and agreement on how these public resources are exploited becomes essential for the survival of those organizations involved in developing act
|
|
| 22. |
|
|
| 23. |
- Karlsson, Fredrik, et al.
(author)
-
Sensor Fused Indoor Positioning Using Dual Band WiFi Signal Measurements
- 2015
-
In: 2015 European Control Conference (ECC). - 9783952426937 ; , s. 1669-1672
-
Conference paper (peer-reviewed)abstract
- In this paper, signal strengths from known WiFi access points are used together with a particle filter to perform indoor navigation. It is shown that more information is obtained by using signals of both 2.4 and 5.0 GHz, compared to using only one frequency. Thus, using both frequencies provides a more accurate positioning. The second contribution is an algorithm where WiFi measurements are combined with pedestrian dead reckoning (PDR), which is based on step counting using an accelerometer and hypotheses of the heading using a gyroscope. This was found to provide further accuracy compared to more conventional methods.
|
|
| 24. |
- Kesarimangalam, Sriram, 1983, et al.
(author)
-
Fluorescence Microscopy of Nanochannel-Confined DNA
- 2024
-
In: Methods in Molecular Biology. - 1940-6029 .- 1064-3745. - 9781071633779 - 9781071633762 ; 2694, s. 175-202
-
Book chapter (other academic/artistic)abstract
- Stretching of DNA in nanoscale confinement allows for several important studies. The genetic contents of the DNA can be visualized on the single DNA molecule level, and the polymer physics of confined DNA and also DNA/protein and other DNA/DNA-binding molecule interactions can be explored. This chapter describes the basic steps to fabricate the nanostructures, perform the experiments, and analyze the data.
|
|
| 25. |
- Mohammad, Moman A., et al.
(author)
-
Incidence and outcome of myocardial infarction treated with percutaneous coronary intervention during COVID-19 pandemic
- 2020
-
In: Heart. - : BMJ Publishing Group Ltd. - 1355-6037 .- 1468-201X. ; 106:23, s. 1812-1818
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: Most reports on the declining incidence of myocardial infarction (MI) during the COVID-19 have either been anecdotal, survey results or geographically limited to areas with lockdowns. We examined the incidence of MI during the COVID-19 pandemic in Sweden, which has remained an open society with a different public health approach fighting COVID-19.METHODS: We assessed the incidence rate (IR) as well as the incidence rate ratios (IRRs) of all MI referred for coronary angiography in Sweden using the nationwide Swedish Coronary Angiography and Angioplasty Registry (SCAAR), during the COVID-19 pandemic in Sweden (1 March 2020-7 May 2020) in relation to the same days 2015-2019.RESULTS: A total of 2443 MIs were referred for coronary angiography during the COVID-19 pandemic resulting in an IR 36 MIs/day (204 MIs/100 000 per year) compared with 15 213 MIs during the reference period with an IR of 45 MIs/day (254 MIs/100 000 per year) resulting in IRR of 0.80, 95% CI (0.74 to 0.86), p<0.001. Results were consistent in all investigated patient subgroups, indicating no change in patient category seeking cardiac care. Kaplan-Meier event rates for 7-day case fatality were 439 (2.3%) compared with 37 (2.9%) (HR: 0.81, 95% CI (0.58 to 1.13), p=0.21). Time to percutaneous coronary intervention (PCI) was shorter during the pandemic and PCI was equally performed, indicating no change in quality of care during the pandemic.CONCLUSION: The COVID-19 pandemic has significantly reduced the incidence of MI referred for invasive treatment strategy. No differences in overall short-term case fatality or quality of care indicators were observed.
|
|
| 26. |
|
|
| 27. |
- Nyberg, Lena, 1979, et al.
(author)
-
Heterogeneous staining: a tool for studies of how fluorescent dyes affect the physical properties of DNA
- 2013
-
In: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 41:19, s. articlenr e184-
-
Journal article (peer-reviewed)abstract
- The commonly used fluorescent dye YOYO-1 (YOYO) has, using bulk techniques, been demonstrated to stain DNA heterogeneously at substoichiometric concentrations. We here, using nanofluidic channels and fluorescence microscopy, investigate the heterogeneous staining on the single DNA molecule level and demonstrate that the dye distribution is continuous. The equilibration of YOYO on DNA is extremely slow but can be accelerated by increasing the ionic strength and/or the temperature. Furthermore, we demonstrate how to use the heterogeneous staining as a tool for detailed and time-efficient studies of how fluorescent dyes affect the physical properties of DNA. We show that the relative increase in extension of DNA with increasing amount of YOYO bound is higher at low ionic strengths and also extrapolate the extension of native DNA. Our study reveals important information on how YOYO affects the physical properties of DNA, but it also has broader applications. First, it reveals how cationic intercalators, such as potential DNA drugs, affect DNA under strong confinement. Second, the strategy of using heterogeneous staining is of general use for single molecule studies of DNA interacting with proteins or ligands.
|
|
| 28. |
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
- Persson, Fredrik, et al.
(author)
-
Fluorescence microscopy of nanochannel-confined DNA
- 2011
-
In: Single Molecule Analysis : Methods and Protocols - Methods and Protocols. - Totowa, NJ : Humana Press. - 1064-3745. - 9781617792816 ; 783, s. 159-179
-
Book chapter (peer-reviewed)abstract
- Stretching of DNA in nanoscale confinement allows for direct visualization of the genetic contents of the DNA on the single DNA molecule level. DNA stretched in nanoscale confinement also allows for studies of DNA-protein interactions and DNA polymer physics in confined environments. This chapter describes the basic steps to fabricate the nanostructures, to perform the experiments, and to analyze the data.
|
|
| 33. |
- Persson, Fredrik, 1973, et al.
(author)
-
High-resolution array CGH analysis of salivary gland tumors reveals fusion and amplification of the FGFR1 and PLAG1 genes in ring chromosomes
- 2008
-
In: Oncogene. - : Springer Science and Business Media LLC. - 0950-9232 .- 1476-5594. ; 27:21, s. 3072-3080
-
Journal article (peer-reviewed)abstract
- We have previously identified a subgroup of pleomorphic salivary gland adenomas with ring chromosomes of uncertain derivation. Here, we have used spectral karyotyping (SKY), fluorescence in situ hybridization (FISH) and high-resolution oligonucleotide array-CGH to determine the origin and content of these rings and to identify genes disrupted as a result of ring formation. Of 16 tumors with rings, 11 were derived from chromosome 8, 3 from chromosome 5 and 1 each from chromosomes 1, 6 and 9. Array-CGH revealed that 10/11 r(8) consisted of amplification of a 19 Mb pericentromeric segment with recurrent breakpoints in FGFR1 in 8p12 and in PLAG1 in 8q12.1. Molecular analyses revealed that ring formation consistently generated novel FGFR1-PLAG1 gene fusions in which the 5'-part of FGFR1 is linked to the coding sequence of PLAG1. An alternative mechanism of PLAG1 activation was found in tumors with copy number gain of an intact PLAG1 gene. Rings derived from chromosomes 1, 5, 6 or 9 did not result in gene fusions, but rather resulted in losses indicative of the involvement of putative tumor suppressor genes on 8p, 5p, 5q and/or 6q. Our findings also reveal a novel mechanism by which FGFR1 contributes to oncogenesis and further illustrate the versatility of the FGFR1 and PLAG1 genes in tumorigenesis.
|
|
| 34. |
- Persson, Fredrik, 1979, et al.
(author)
-
Lipid-Based Passivation in Nanofluidics
- 2012
-
In: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 12:5, s. 2260-2265
-
Journal article (peer-reviewed)abstract
- Stretching DNA in nanochannels is a useful tool for direct, visual studies of genomic DNA at the single molecule level. To facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We demonstrate virtually complete long-term passivation of nanochannel surfaces to a range of relevant reagents, including streptavidin-coated quantum dots, RecA proteins, and RecA-DNA complexes. We show that the performance of the lipid bilayer is significantly better than that of standard bovine serum albumin-based passivation. Finally, we show how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation by DNase I. We expect that our approach will open up for detailed, systematic studies of a wide range of protein-DNA interactions with high spatial and temporal resolution.
|
|
| 35. |
- Persson, Fredrik, 1979, et al.
(author)
-
Local conformation of confined DNA studied using emission polarization anisotropy
- 2010
-
In: Biophysical Society 54th Annual Meeting.
-
Conference paper (other academic/artistic)abstract
- When confined in nanochannels with dimensions smaller than the DNA radius of gyration, DNA will extend along the channel. We investigate long DNA confined in nanochannels, using fluorescence microscopy and intercalated dyes. Studies of the dynamics and statics of DNA in such nanoscale confinements as a function of e.g. degree of confinement and ionic strength have yielded new insights into the physical properties of DNA with relevance for applications in genomics as well as fundamental understanding of DNA packaging in vivo. Our work extends the field by not only studying the location of the emitting dyes along a confined DNA molecule but also monitoring the polarization of the emitted light. By measuring the emission polarized parallel and perpendicular to the extension axis of the stretched DNA, information on the local spatial distribution of the DNA backbone can be obtained. Comparing polarizations in two directions for DNA confined in channels of effective diameters of 85 nm and 170 nm reveals a striking difference. Whereas the DNA in the larger channels shows an isotropic polarization of the emitted light, the light is to a large extent polarized perpendicular to the elongation of the DNA in the smaller channels. We expect this technique to have a large impact on the studies of changes in DNA conformation induced by protein binding or during DNA compactation as well as in fundamental polymer physics studies of DNA in confined environments, for example in bacterial spores and viruses.
|
|
| 36. |
- Persson, Fredrik, 1979, et al.
(author)
-
Local conformation of confined DNA studied using emission polarization anisotropy
- 2010
-
In: NanoBioTech-Montreux 2009.
-
Conference paper (other academic/artistic)abstract
- In nanochannels with dimensions smaller than the DNA radius of gyration, DNA will extend along the channel. We investigate long DNA confined in nanochannels using fluorescence microscopy and intercalated dyes. Studies of the dynamics and statics of the DNA extension or position in such nanoscale confinements as a function of e.g. DNA contour length, degree and shape of confinement as well as ionic strength have yielded new insights in the physical properties of DNA with relevance for applications in genomics as well as fundamental understanding of DNA packaging in vivo. Our work extends the field by not only studying the location of the emitting dyes along a confined DNA molecule but also monitoring the polarization of the emitted light. We use intercalating dyes (YOYO-1) whose emission is polarized perpendicular to the DNA extension axis, and by measuring the emission polarized parallel and perpendicular to the extension axis of the stretched DNA, information on the local spatial distribution of the DNA backbone can be obtained. The results obtained are analogous to linear dichroism (LD) but on a single-molecule level, and obtained in a highly parallel fashion. We will discuss results in shallow (60 nm) and deep (180 nm) channels and describe an example of how the technique can be used to investigate non-uniform stretching of DNA on the single molecule level. Comparing polarizations in two directions for DNA confined in channels of effective diameters of 85 nm and 170 nm reveals a striking difference. Whereas the DNA in the larger channels shows an isotropic polarization of the emitted light, the light is to a large extent polarized perpendicular to the elongation of the DNA in the smaller channels. The ratio of the polarization parallel and perpendicular to the elongation direction, I|| / I⊥, is a measure of the relative local orientation of the DNA backbone. We believe that this technique will have a large impact on the studies of changes in DNA conformation induced by protein binding or during DNA compactation as well as in fundamental polymer physics studies of DNA in confined environments, for example in bacterial spores and viruses.
|
|
| 37. |
|
|
| 38. |
- Persson, Fredrik, et al.
(author)
-
Polarization anisotropy of DNA in nanochannels
- 2008
-
In: ; , s. 668-670
-
Conference paper (peer-reviewed)abstract
- The local alignment of DNA stretched in nanofluidic channels is measured using polarization sensitive detection. With increased degree of stretching the polarization anisotropy increases both in the deGennes and the Odijk regime. The technique is expected to find use in studies of, for example, local conformational changes in polymer physics in confined spaces, studies of protein-DNA interactions and compactation of DNA.
|
|
| 39. |
- Persson, Fredrik, et al.
(author)
-
Supply chain dynamics in the SCOR model : A simulation modeling approach
- 2012
-
In: Proceedings of the 2012 Winter Simulation Conference (WSC). - Piscataway, NJ, USA : IEEE. ; , s. 1-12
-
Conference paper (peer-reviewed)abstract
- Supply Chain Simulation (SCS) is today a well-defined branch of discrete-event simulation applications. The differences between different applications are usually small, but in the case of SCS, models tend to be larger, take longer time to build and are harder to validate. To remedy some of these issues in SCS, we propose to use the SCOR model (Supply Chain Operations Reference Model) as a tool to speed up the simulation modeling of supply chains. The SCOR model can be useful in the conceptual phase, the modeling phase, and in the experimental phase of a simulation project. In SCOR Template, a modeling template in Arena, all level 3 processes of Source, Make, and Deliver are modeled to provide the SCS model builder a tool that is fast, follows the SCOR standards in processes and metrics, and simple to use. Here we report on the third version of the SCOR Template.
|
|
| 40. |
- Persson, Marta, 1979, et al.
(author)
-
Clinically significant copy number alterations and complex rearrangements of MYB and NFIB in head and neck adenoid cystic carcinoma.
- 2012
-
In: Genes, chromosomes & cancer. - : Wiley. - 1098-2264 .- 1045-2257. ; 51:8, s. 805-17
-
Journal article (peer-reviewed)abstract
- Adenoid cystic carcinoma (ACC) of the head and neck is a malignant tumor with poor long-term prognosis. Besides the recently identified MYB-NFIB fusion oncogene generated by a t(6;9) translocation, little is known about other genetic alterations in ACC. Using high-resolution, array-based comparative genomic hybridization, and massively paired-end sequencing, we explored genomic alterations in 40 frozen ACCs. Eighty-six percent of the tumors expressed MYB-NFIB fusion transcripts and 97% overexpressed MYB mRNA, indicating that MYB activation is a hallmark of ACC. Thirty-five recurrent copy number alterations (CNAs) were detected, including losses involving 12q, 6q, 9p, 11q, 14q, 1p, and 5q and gains involving 1q, 9p, and 22q. Grade III tumors had on average a significantly higher number of CNAs/tumor compared to Grade I and II tumors (P = 0.007). Losses of 1p, 6q, and 15q were associated with high-grade tumors, whereas losses of 14q were exclusively seen in Grade I tumors. The t(6;9) rearrangements were associated with a complex pattern of breakpoints, deletions, insertions, inversions, and for 9p also gains. Analyses of fusion-negative ACCs using high-resolution arrays and massively paired-end sequencing revealed that MYB may also be deregulated by other mechanisms in addition to gene fusion. Our studies also identified several down-regulated candidate tumor suppressor genes (CTNNBIP1, CASP9, PRDM2, and SFN) in 1p36.33-p35.3 that may be of clinical significance in high-grade tumors. Further, studies of these and other potential target genes may lead to the identification of novel driver genes in ACC.
|
|
| 41. |
- Persson, Marta, 1979, et al.
(author)
-
Recurrent fusion of MYB and NFIB transcription factor genes in carcinomas of the breast and head and neck
- 2009
-
In: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 106:44, s. 18740-4
-
Journal article (peer-reviewed)abstract
- The transcription factor gene MYB was identified recently as an oncogene that is rearranged/duplicated in some human leukemias. Here we describe a new mechanism of activation of MYB in human cancer involving gene fusion. We show that the t(6;9)(q22-23;p23-24) translocation in adenoid cystic carcinomas (ACC) of the breast and head and neck consistently results in fusions encoding chimeric transcripts predominantly consisting of MYB exon 14 linked to the last coding exon(s) of NFIB. The minimal common part of MYB deleted as the result of fusion was exon 15 including the 3'-UTR, which contains several highly conserved target sites for miR-15a/16 and miR-150 microRNAs. These microRNAs recently were shown to regulate MYB expression negatively. We suggest that deletion of these target sites may disrupt repression of MYB leading to overexpression of MYB-NFIB transcripts and protein and to activation of critical MYB targets, including genes associated with apoptosis, cell cycle control, cell growth/angiogenesis, and cell adhesion. Forced overexpression of miR-15a/16 and miR-150 in primary fusion-positive ACC cells did not significantly alter the expression of MYB as compared with leukemic cells with MYB activation/duplication. Our data indicate that the MYB-NFIB fusion is a hallmark of ACC and that deregulation of the expression of MYB and its target genes is a key oncogenic event in the pathogenesis of ACC. Our findings also suggest that the gain-of-function activity resulting from the MYB-NFIB fusion is a candidate therapeutic target.
|
|
| 42. |
- Persson, Patrik, et al.
(author)
-
Adenosine A(2)a receptor stimulation prevents proteinuria in diabetic rats by promoting an anti-inflammatory phenotype without affecting oxidative stress
- 2015
-
In: Acta Physiologica. - : Wiley: 12 months. - 1748-1708 .- 1748-1716. ; 214:3, s. 311-318
-
Journal article (peer-reviewed)abstract
- AimDiabetic patients are at increased risk for kidney disease. There is presently no clinical treatment available that effectively protects kidney function in diabetics. This study investigates whether chronic stimulation of the adenosine A(2a) receptor (A(2a)AR) protects kidney function in insulinopenic diabetic rats. MethodsStreptozotocin-induced diabetic rats and corresponding controls were chronically treated with the adenosine A(2a)AR agonist CGS21680 throughout the four-week diabetes duration. Kidney function was thereafter investigated, and urine and plasma samples were collected for analysis of protein, oxidative stress and inflammatory markers. ResultsGlomerular filtration rate, renal blood flow, filtration fraction and diabetes-induced kidney hypoxia were all unaffected by chronic A(2a)AR stimulation. Furthermore, diabetic rats had increased oxidative stress, which was further increased by chronic A(2a)AR stimulation. However, the 10-fold increased urinary protein excretion observed in the diabetic rats was completely prevented by chronic A(2a)AR stimulation. These beneficial effects were accompanied by reduced levels of the pro-inflammatory TNF- and increased levels of the anti-inflammatory IL-10 as well as decreased infiltration of macrophages, glomerular damage and basement membrane thickness. ConclusionChronic A(2a)AR stimulation prevents proteinuria and glomerular damage in experimental diabetes via an anti-inflammatory mechanism independent of oxidative stress and kidney hypoxia.
|
|
| 43. |
|
|
| 44. |
- Rusek, Fredrik, et al.
(author)
-
Scaling up MIMO : Opportunities and Challenges with Very Large Arrays
- 2013
-
In: IEEE signal processing magazine (Print). - : IEEE. - 1053-5888 .- 1558-0792. ; 30:1, s. 40-60
-
Journal article (peer-reviewed)abstract
- Multiple-input multiple-output (MIMO) technology is maturing and is being incorporated into emerging wireless broadband standards like long-term evolution (LTE) [1]. For example, the LTE standard allows for up to eight antenna ports at the base station. Basically, the more antennas the transmitter/receiver is equipped with, and the more degrees of freedom that the propagation channel can provide, the better the performance in terms of data rate or link reliability. More precisely, on a quasi static channel where a code word spans across only one time and frequency coherence interval, the reliability of a point-to-point MIMO link scales according to Prob(link outage) ` SNR-ntnr where nt and nr are the numbers of transmit and receive antennas, respectively, and signal-to-noise ratio is denoted by SNR. On a channel that varies rapidly as a function of time and frequency, and where circumstances permit coding across many channel coherence intervals, the achievable rate scales as min(nt, nr) log(1 + SNR). The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time [2].
|
|
| 45. |
- Sahlgren, Magnus, et al.
(author)
-
The Gavagai Living Lexicon
- 2016
-
In: 10th edition of the Language Resources and Evaluation Conference, 23-28 May 2016, Portorož (Slovenia). - : ELRA.
-
Conference paper (peer-reviewed)abstract
- This paper presents the Gavagai Living Lexicon, which is an online distributional semantic model currently available in 14 different languages. We describe the underlying distributional semantic model, and how we have solved some of the challenges in applying such a model to large amounts of streaming data. We also describe the architecture of our implementation, and discuss how we deal with continuous quality assurance of the lexicon.
|
|
| 46. |
- Sehlstedt-Persson, Margot, et al.
(author)
-
Robust processtyrning av vandringstorkar för jämnare torkningskvalitet
- 2015
-
Reports (other academic/artistic)abstract
- Under 2000-talet har vandringstorkarna genomgått något av en renässans och alltfler verk har investerat i nya vandringstorkar med stor kapacitet och helt nya möjligheter. Kunskapen om att styra dessa vandringstorkar för att få en jämn löpande torkningskvalitet har dock hamnat på efterkälken. Det finns ett stort kunskapsbehov att fylla för att förstå processen, kunna hantera avvikelser, tolka och hantera processparametrar, att ha en plan när något ”går snett” för att våga röra styrparametrar och tolka konsekvenserna i dessa trögstyrda system. Syftet med denna förstudie är identifiera de problemställningar som dagens ansvariga för styrning av vandringstorkar måste hantera. Målet är att få en jämnare torkningskvalitet samt en fördjupad förståelse av hur torkningsprocessen ska styras och göras mer robust. Förstudien inleddes med en entusiastisk workshop med god uppslutning från industrin där en gemensam prioritering gjordes av ett antal punkter som förstudien har fokuserat på nämligen medelvärdesstyrning i zon 1 och 2, tryckfallsmätning över batteri samt test av en ny typ av lufthastighetsgivare. Övriga frågor som prioriterades högt har på grund av förstudiens begränsade resurser ej kunnat genomföras i förstudien utan finns med i framtida arbete. • Inledande försök med medelvärdesstyrning i zon 1, samt i både zon 1 och zon 2, visar fördelar med förbättrad målfuktkvotsträff, mindre fuktkvotsspridning och färre ändringar i satsningstider. • Inledande mätningar av differenstryck över batteri som signal för att indikera när värmebatterier behöver rengöras från spånlimning bedöms vara en lovande metod med tydliga signaler. Fortsatt arbete med att få en kontinuerlig mätning över en hel vintersäsong fortgår. Förhoppningsvis kommer faktiska effekter på cirkulationsfläktarnas elförbrukning och/eller lufthastigheten genom virket kunna påvisas.• Den nya lufthastighetsgivaren som kopplades till en datalogger och kördes igenom kanalen flera gånger fungerade väl. Ytterligare tester genomförda av Valutec med liknande givare har slagit väl ut och har varit ett bra hjälpmedel vid t.ex. felsökning.
|
|
| 47. |
- Sehlstedt-Persson, Margot, et al.
(author)
-
Virkestorkningens inverkan på impregnerbarhet i furusplint – Del II : TCN Delrapport 1
- 2013
-
Reports (other academic/artistic)abstract
- Projektets målsättning är att undersöka om och hur virkestorkning påverkar impregnerbarhet i furusplint med vattenbaserat kopparmedel, samt att ge rekommendationer om hur torkningsbetingelserna kan göras så gynnsamma som möjligt för ett bra impregneringsresultat. Det bör tydliggöras att det virke som impregnerats i denna studie inte kommer att säljas inom detaljhandeln. Virket anses inte heller vara representativt för impregnerat virke då det har impregnerats vid fuktkvoter som avsiktligt avviker från normala förhållanden och som kan antas vara ogynnsamma för inträngningen. Virket impregnerades enligt Nordiska Träskyddsföreningen (NTR) klass AB.I delsteg 1 som avrapporteras i denna rapport, har huvudfrågan varit att undersöka inverkan av fuktkvotsnivå och maxtemperatur under torkningen på impregneringsresultatet. Försöksmaterialet har bestått av totalt 553 hyvlade bräder och plank (28 resp. 48 mm). Både planken och bräderna sågades fram ur centrumutbyte och innehöll därför kärnved. Virket torkades industriellt vid 60°C och 80°C maxtemperatur till tre målfuktkvoter: 24 %, 18 % och 10 %. Efter impregnering har samtliga virkesstycken kapats upp var 50:e cm och impregneringsresultat har analyserats visuellt enligt NTR:s bedömningsgrunder. Vissa kemiska analyser har även utförts för att undersöka om och hur extraktiver och fetter kan förklara impregneringsmissarna i bräderna. Undersökningen visar att virkesdimension, fuktkvot och temperaturnivå har betydelse för impregneringsresultatet. Totalt sett fanns det fler missar i planken än i bräderna. Plank och bräder uppvisar dessutom något olika beteende: för bräder är resultatet mera tydligt vilket även framkom vid multivariat dataanalys (MVDA) på medelvärdesnivå: högre temperatur och högre fuktkvot visar minst impregneringsmissar hos brädgrupperna. För plankgrupper erhölls överhuvudtaget inga MVDA-modeller. Även för plank hade den högre temperaturen i medel bättre impregneringsresultat. Sambandet hög fuktkvot och god impregnerbarhet är inte lika tydligt för plank, möjligen att kombinationen låg temperatur och låg fuktkvot är ogynnsam.Densitetsvariationerna visade sig vara tämligen liten och inga låga/höga extremvärden fanns i försöksmaterialet. Vid MVDA framkom ändå tendenser att det hos bräder var gynnsamt ur impregneringssynpunkt med högre densitet.Kemiska analyser visar inga dramatiska omfördelningar av extraktiver under torkning som förklaring till impregneringsmissar. Detekterbara fetter och hartssyror var dock lägre i ytliga än i inre delar av splintveden troligen beroende på oxidativ förnätning av deras struktur under torkningen.Sammanfattningsvis blir tolkningen att torktemperatur, fuktkvotsintervall och virkesdimensioner har betydelse för impregneringsresultat men att det finns ett antal okända materialvariabler som har stor inverkan på resultatet på individnivå. Även om torkningsbetingelserna görs så gynnsamma som möjligt för impregnering förekommer individer som har allvarliga genomgående missar.
|
|
| 48. |
- Sehlstedt-Persson, Margot, et al.
(author)
-
Virkestorkningens inverkan på impregnerbarhet i furusplint – Del II : TCN Delrapport 2 Inverkan av mellanlagring och konditionering
- 2013
-
Reports (other academic/artistic)abstract
- Projektets målsättning är att undersöka om och hur virkestorkning påverkar impregnerbar-het i furusplint med vattenbaserat kopparmedel, samt att ge rekommendationer om hur torkningsbetingelserna kan göras så gynnsamma som möjligt för ett bra impregnerings-resultat.I delsteg 2 som avrapporteras i denna rapport, har huvudfrågan varit att undersöka hur torkningsparametrarna fuktkvotsgradient, torkningsspänningar, konditionering och mellan-lagringstid mellan torkning och impregnering påverkar impregneringsresultatet i ohyvlade, centrumsågade furuplank 50x125 mm som torkats i labbtork till målfuktkvoten 18 % vid max torrtemperatur 75°C.Försöksvirket har impregnerats med kopparbaserat medel enligt Nordiska Träskydds-föreningen (NTR) klass AB. Det försöksvirke som impregnerats i denna studie uppvisar stor andel impregneringsmissar då det har impregnerats under förhållanden som avviker från normala produktionsförhållanden och som antas vara ogynnsamma för inträngningen. Det bör därför starkt betonas att impregneringsresultatet från denna studie inte är representa-tivt för normal produktion av impregnerat virke i klass AB. Men, eftersom målet med denna undersökning har varit att undersöka inverkan av rena torkningsparametrar ses inte detta som något som helst problem vid analysen eftersom samtliga provbitar varit behandlade på samma sätt och impregnerats i samma tryckning.Undersökningen visar* att konditionering av virke före impregnering tenderar att öka impregnerings-missarna i ohyvlat virke.* att hög fuktkvot, som t.ex. kan bero på att plankorna är blötare i mitten, dvs. en hög fuktkvotsgradient, är gynnsamt för impregneringen.* ingen inverkan av torkspänningarnas storlek på impregneringsresultatet.* att mellanlagring av virke mellan torkning och impregnering ökar andelen missar. Detta resultat förklaras sannolikt av att fuktkvotsgradienterna minskar under mellanlagringen och att stora gradienter visade sig vara gynnsamt för impregnering.Sammanfattningsvis visar studien att bästa impregneringsresultatet erhålls om ohyvlat virke inte konditioneras utan impregneras direkt efter torkning utan någon mellanlagring. Konditionering visade sig försämra resultatet och en trolig förklaring till detta bedöms vara att konditioneringen ökar kådvandringen i splintens kådkanaler ut på splintvedytorna vilket försvårar medelinträngningen.
|
|
| 49. |
|
|
| 50. |
|
|
