| 1. |
- Lundberg, Jan, et al.
(författare)
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High-speed video photographs of lubrication breakdown in squeeze-sliding contact
- 1992
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Ingår i: Wear. - 0043-1648 .- 1873-2577. ; 157:2, s. 427-433
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Tidskriftsartikel (refereegranskat)abstract
- Using photographs from a high-speed video camera it was confirmed that the main part of breakdown of a lubricating film will appear at the end of the contact time for a contact simultaneously subjected to squeeze and sliding motion. This corresponds with earlier findings using totally different equipment for electric detection of the asperity contact. The present investigation used glass and steel as the lubricated surfaces, instead of steel and steel as was the case in the earlier investigation. In combination with far less stiff equipment, the new materials gave longer contact time and larger elastic deformations of the contact bodies. It was also verified that increased surface roughness, increased sliding velocity and decreased viscosity increase the risk of oil film breakdown
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| 2. |
- Adenskog, Magnus, 1985-
(författare)
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Democratic innovations in political systems : towards a systemic approach
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There are many indicators that the representative democratic system is currently facing serious legitimacy challenges. Two central indicators of these challenges are changing patterns of political participation and a decline in system support. Against this backdrop, a growing number of governments claim that democratic innovations (DIs) could reconnect institutions with citizens. This thesis focuses on online DIs implemented in real political contexts, and the overarching aim of the thesis is to contribute to the emergent empirical scholarship on how DIs can influence political systems. In the last two decades, most empirical studies in the field have analysed DIs at the micro level.This thesis takes a different stance by posing system-related research questions to the implementation of DIs and, by doing so, showing how DIs are interrelated with, rather than isolated from, the political system and that DIs can influence political systems. The thesis consists of one literature review and three empirical case studies, applying a multiple methodological approach. Its novelty lies in three main empirical findings that contribute to the development of the field. First, it shows that participation in DIs can influence citizens’ perceived trust towards local political institutions. In addition, the results suggest that predispositions and prior engagement mediate the direction of change in trust amongst citizens. Secondly, the results show that DIs can perform different political functions, such as facilitating spaces for citizens to provide original ideas and deliberation, while also having an agenda-setting function. Thirdly, the result suggest that long-term institutional change is complex and that the implementation of DIs can create a situation in which civil servants and politicians perceive their organisation to be in some ‘state of flux’, as they are torn between two competing institutional logics. In conclusion, this thesis should be understood as a piece in a broader movement that works towards a systemic approach to the study of DIs, and that by showing these empirical findings, the thesis contributes to deepening our understanding of what influences and functions DIs can have in political systems.
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| 3. |
- Aneq Åström, Meriam, et al.
(författare)
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Determination of right ventricular volume and function using multiple axially rotated MRI slices
- 2011
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Ingår i: Clinical Physiology and Functional Imaging. - : Blackwell Publishing Ltd. - 1475-0961 .- 1475-097X. ; 31:3, s. 233-239
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Tidskriftsartikel (refereegranskat)abstract
- Pandgt;Background: The conventional magnetic resonance imaging (MRI) method for right ventricular (RV) volume and motion, using short-axis (SA) orientation, is limited by RV anatomy and shape. We suggest an orientation based on six slices rotated around the long axis of the RV, rotated long axis (RLA). Materials and methods: Three phantoms were investigated in SA and RLA using cine balanced steady-state free precession MRI. Volumes were calculated based on segmentation and checked against true volumes. In 23 healthy male volunteers, we used six long-axis planes from the middle of the tricuspid valve to the RV apex, rotated in 30 degrees increments. For comparison, short-axis slices were acquired. Imaging parameters were identical in both acquisitions. Results: Right ventricular end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV) determined in the RLA 179 center dot 1 +/- 29 center dot 3; 80 center dot 1 +/- 17 center dot 1; 99 center dot 3 +/- 16 center dot 9 ml and in the SA were 174 center dot 0 +/- 21 center dot 1; 78 center dot 8 +/- 13 center dot 6; 95 center dot 3 +/- 14 center dot 5 ml with P-values for the difference from 0 center dot 17 to 0 center dot 64 (ns). Interobserver variability ranged between 3 center dot 2% and 6 center dot 6% and intraobserver variability between 2 center dot 8% and 6 center dot 8%. In SA views, consensus for the definition of the basal slice was necessary in 39% of the volunteers for whom the average volume change was 20% in ESV and 10% in EDV. Conclusions: The RLA method results in better visualization and definition of the RV inflow, outflow and apex. Accurate measurement of RV volumes for diagnosis and follow-up of cardiac diseases are enhanced by the RLA orientation, even though additional acquisition time is required.
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| 4. |
- Aneq Åström, Meriam, et al.
(författare)
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Evaluation of Right and Left Ventricular Function Using Speckle Tracking Echocardiography in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy and Their First Degree Relatives
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Introduction and aim: The identification of right ventricular abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in early stages is still difficult. The aim of this study was to investigate if longitudinal strain based on speckle tracking can detect subtle right (RV) or left ventricular (LV) dysfunction as an early sign of ARVC. Methods and results: Seventeen male patients, fulfilling Task force criteria for ARVC, 49 (32-70) years old, nineteen male first degree relatives 29 (19-73) y.o. and twenty-two healthy male volunteers 36 (24-66) y.o participated in the study. Twelve-lead and signal-averaged electrocardiograms were recorded. All subjects underwent echocardiography. LV and RV diameters, peak systolic velocity from tissue Doppler and longitudinal strain based on speckle tracking were measured from the basal and mid segments in both ventricles. RV longitudinal strain measurement was successful in first degree relatives and controls (95 resp. 86%) but less feasible in patients (59%). Results were not systematically different between first degree relatives and controls. Using discriminant analysis, we then developed an index based on echocardiographic parameters. All normal controls had an index Conclusion: Longitudinal strain of LV and RV segments was significantly lower in patients than in relatives and controls. An index was developed incorporating dimensional and functional echocardiographic parameters. In combination with genetic testing this index might help to detect early phenotype expression in mutation carriers.
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| 5. |
- Aneq Åström, Meriam, et al.
(författare)
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Novel plakophilin2 mutation. Three generation family with arrhythmogenic right ventricular cardiomyopathy
- 2012
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa Healthcare. - 1401-7431 .- 1651-2006. ; 46:2, s. 72-75
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The autosomal dominant form of arrhythmogenic right ventricular cardiomyopathy (ARVC)has been linked to mutations in desmosomal proteins. Different studies have shown that amutation in plakophilin-2 (PKP 2) is a frequent genetic cause for ARVC. We describe a newmutation in the PKP2 gene, the genotype-phenotype variation in this mutation and its clinicalconsequences. Design: Individuals in a three generation family were investigated after the sudden cardiac death of a young male. Clinical evaluation, electrocardiography, echocardiography, magnetic resonance imaging, endomyocardial biopsy and genetic testing were performed. Results: A novel heterozygote mutation, a c.368G>A transition, located in exon 3 of the PKP2 gene was found (p.Trp123X). The phenotype was characterized by arrhythmia at an early age in some individuals, with mild abnormalities on imaging. However a relative carrying this mutation, with positive findings on endomyocardial biopsy had an otherwise normal phenotype, for 16 years, whereas a relative fulfilling the modified Task Force Criteria for ARVC turned out to be a non-carrier. Conclusions: This shows the variable penetrance and phenotypic expression in ARVC and highlights the need of genetic testing as well as a thorough phenotype examination as a part of the investigations in ARVC pedigrees.
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| 6. |
- Armstrong, Ben, et al.
(författare)
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The Role of Humidity in Associations of High Temperature with Mortality : A Multicountry, Multicity Study
- 2019
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Ingår i: Journal of Environmental Health Perspectives. - : The National Institute of Environmental Health Sciences. - 0091-6765 .- 1552-9924. ; 127:9
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is strong experimental evidence that physiologic stress from high temperatures is greater if humidity is higher. However, heat indices developed to allow for this have not consistently predicted mortality better than dry-bulb temperature.Objectives: We aimed to clarify the potential contribution of humidity an addition to temperature in predicting daily mortality in summer by using a large multicountry dataset.Methods: In 445 cities in 24 countries, we fit a time-series regression model for summer mortality with a distributed lag nonlinear model (DLNM) for temperature (up to lag 3) and supplemented this with a range of terms for relative humidity (RH) and its interaction with temperature. City-specific associations were summarized using meta-analytic techniques.Results: Adding a linear term for RH to the temperature term improved fit slightly, with an increase of 23% in RH (the 99th percentile anomaly) associated with a 1.1% [95% confidence interval (CI): 0.8, 1.3] decrease in mortality. Allowing curvature in the RH term or adding terms for interaction of RH with temperature did not improve the model fit. The humidity-related decreased risk was made up of a positive coefficient at lag 0 outweighed by negative coefficients at lags of 1–3 d. Key results were broadly robust to small model changes and replacing RH with absolute measures of humidity. Replacing temperature with apparent temperature, a metric combining humidity and temperature, reduced goodness of fit slightly.Discussion:The absence of a positive association of humidity with mortality in summer in this large multinational study is counter to expectations from physiologic studies, though consistent with previous epidemiologic studies finding little evidence for improved prediction by heat indices. The result that there was a small negative average association of humidity with mortality should be interpreted cautiously; the lag structure has unclear interpretation and suggests the need for future work to clarify.
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| 7. |
- Berg, Ingrid L., et al.
(författare)
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MutS alpha deficiency increases tolerance to DNA damage in yeast lacking postreplication repair
- 2020
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Ingår i: DNA Repair. - : Elsevier BV. - 1568-7864 .- 1568-7856. ; 91-92
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Tidskriftsartikel (refereegranskat)abstract
- By combining mutations in DNA repair genes, important and unexpected interactions between different repair pathways can be discovered. In this study, we identified a novel link between mismatch repair (MMR) genes and postreplication repair (PRR) in Saccharomyces cerevisiae. Strains lacking Rad5 (HLTF in mammals), a protein important for restarting stalled replication forks in the error-free PRR pathway, were supersensitive to the DNA methylating agent methyl methanesulfonate (MMS). Deletion of the mismatch repair genes, MSH2 or MSH6, which together constitutes the MutS alpha complex, partially suppressed the MMS super-sensitivity of the rad5 Delta, strain. Deletion of MSH2 also suppressed the MMS sensitivity of mms2 Delta, which acts together with Rad5 in error-free PRR. However, inactivating the mismatch repair genes MSH3 and MLH1 did not suppress rad5 Delta, showing that the suppression was specific for disabling MutS alpha. The partial suppression did not require translesion DNA synthesis (REV1, REV3 or RAD30), base excision repair (MAGI) or homologous recombination (RAD51). Instead, the underlying mechanism was dependent on RAD52 while independent of established pathways involving RAD52, like single-strand annealing and break-induced replication. We propose a Rad5- and Rad51-independent template switch pathway, capable of compensating for the loss of the error-free template-switch subpathway of postreplication repair, triggered by the loss of MutS alpha.
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| 8. |
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| 9. |
- Blixt Johansson, Patrik, et al.
(författare)
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Left ventricular longitudinal wall fractional shortening accurately predicts longitudinal strain in critically ill patients with septic shock
- 2021
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Ingår i: Annals of Intensive Care. - : Springer. - 2110-5820. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Left ventricular longitudinal strain (LVLS) may be a sensitive indicator of left ventricular (LV) systolic function in patients with sepsis, but is dependent on high image quality and analysis software. Mitral annular plane systolic excursion (MAPSE) and the novel left ventricular longitudinal wall fractional shortening (LV-LWFS) are bedside echocardiographic indicators of LV systolic function that are less dependent on image quality. Both are sparsely investigated in the critically ill population, and may potentially be used as surrogates for LVLS. We assessed if LVLS may be predicted by LV-LWFS and MAPSE in patients with septic shock. We also assessed the repeatability and inter-rater agreement of LVLS, LV-LWFS and MAPSE measurements. Results 122 TTE studies from 3 echocardiographic data repositories of patients admitted to ICU with septic shock were retrospectively assessed, of which 73 were suitable for LVLS analysis using speckle tracking. The correlations between LVLS vs. LV-LWFS and LVLS vs. MAPSE were 0.89 (p < 0.001) and 0.81 (p < 0.001) with mean squared errors of 5.8% and 9.1%, respectively. Using the generated regression equation, LV-LWFS predicted LVLS with a high degree of accuracy and precision, with bias and limits of agreement of -0.044 +/- 4.7% and mean squared prediction error of 5.8%. Interobserver repeatability was good, with high intraclass correlation coefficients (0.96-0.97), small bias and tight limits of agreement (<= 4.1% for all analyses) between observers for all measurements. Conclusions LV-LWFS may be used to estimate LVLS in patients with septic shock. MAPSE also performed well, but was slightly inferior compared to LV-LWFS in estimating LVLS. Feasibility of MAPSE and LV-LWFS was excellent, as was interobserver repeatability.
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| 10. |
- Blomstedt, Patric, et al.
(författare)
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Unilateral caudal zona incerta deep brain stimulation for Parkinsonian tremor
- 2012
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Ingår i: Parkinsonism & Related Disorders. - : Elsevier. - 1353-8020 .- 1873-5126. ; 18:10, s. 1062-1066
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Tidskriftsartikel (refereegranskat)abstract
- Background: The subthalamic nucleus is currently the target of choice in deep brain stimulation (DBS) for Parkinsons disease (PD), while thalamic DBS is used in some cases of tremor-dominant PD. Recently, a number of studies have presented promising results from DBS in the posterior subthalamic area, including the caudal zona incerta (cZi). The aim of the current study was to evaluate cZi DBS in tremor-dominant Parkinsons disease. less thanbrgreater than less thanbrgreater thanMethods: 14 patients with predominately unilateral tremor-dominant PD and insufficient relief from pharmacologic therapy were included and evaluated according to the motor part of the Unified Parkinson Disease Rating Scale (UPDRS). The mean age was 65 +/- 6.1 years and the disease duration 7 +/- 5.7 years. Thirteen patients were operated on with unilateral cZi DBS and 1 patient with a bilateral staged procedure. Five patients had non-L-dopa responsive symptoms. The patients were evaluated on/off medication before surgery and on/off medication and stimulation after a minimum of 12 months after surgery. less thanbrgreater than less thanbrgreater thanResults: At the follow-up after a mean of 18.1 months stimulation in the off-medication state improved the contralateral UPDRS III score by 47.7%. Contralateral tremor, rigidity, and bradykinesia were improved by 82.2%, 34.3%, and 26.7%, respectively. Stimulation alone abolished tremor at rest in 10 (66.7%) and action tremor in 8 (533%) of the patients. less thanbrgreater than less thanbrgreater thanConclusion: Unilateral cZi DBS seems to be safe and effective for patients with severe Parkinsonian tremor. The effects on rigidity and bradykinesia were, however, not as profound as in previous reports of DBS in this area.
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