| 1. |
- Alenius Dahlqvist, Jenny, 1972-, et al.
(författare)
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Changes in Heart Rate and Heart Rate Variability During Surgical Stages to Completed Fontan Circulation
- 2021
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Ingår i: Pediatric Cardiology. - : Springer Science and Business Media LLC. - 0172-0643 .- 1432-1971. ; 42:5, s. 1162-1169
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Tidskriftsartikel (refereegranskat)abstract
- Arrhythmia is related to heart rate variability (HRV), which reflects the autonomic nervous regulation of the heart. We hypothesized that autonomic nervous ganglia, located at the junction of the superior vena cava's entrance to the heart, may be affected during the bidirectional Glenn procedure (BDG), resulting in reduced HRV. We aimed to investigate changes in heart rate and HRV in a cohort of children with univentricular heart defects, undergoing stepwise surgery towards total cavopulmonary connection (TCPC), and compare these results with healthy controls. Twenty four hours Holter-ECG recordings were obtained before BDG (n = 47), after BDG (n = 47), and after total cavopulmonary connection (TCPC) (n = 45) in patients and in 38 healthy controls. HRV was analyzed by spectral and Poincare methods. Age-related z scores were calculated and compared using linear mixed effects modeling. Total HRV was significantly lower in patients before BDG when compared to healthy controls. The mean heart rate was significantly reduced in patients after BDG compared to before BDG. Compared to healthy controls, patients operated with BDG had significantly reduced heart rate and reduced total HRV. Patients with TCPC showed reduced heart rate and HRV compared with healthy controls. In patients after TCPC, total HRV was decreased compared to before TCPC. Heart rate was reduced after BDG procedure, and further reductions of HRV were seen post-TCPC. Our results indicate that autonomic regulation of cardiac rhythm is affected both after BDG and again after TCPC. This may be reflected as, and contribute to, postoperative arrhythmic events.
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| 2. |
- Almby, Kristina E., et al.
(författare)
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Effects of Gastric Bypass Surgery on the Brain : Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia
- 2021
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 70:6, s. 1265-1277
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Tidskriftsartikel (refereegranskat)abstract
- While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by F-18-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.
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| 3. |
- Almby, Kristina E., et al.
(författare)
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Time course of metabolic, neuroendocrine, and adipose effects during 2 years of follow-up after gastric bypass in patients with type 2 diabetes
- 2021
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : Oxford University Press. - 0021-972X .- 1945-7197. ; 106:10, s. E4049-E4061
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Tidskriftsartikel (refereegranskat)abstract
- Context: Roux-en-Y gastric bypass surgery (RYGB) markedly improves glycemia in patients with type 2 diabetes (T2D), but underlying mechanisms and changes over time are incompletely understood.Objective: Integrated assessment of neuroendocrine and metabolic changes over time inT2D patients undergoing RYGB.Design and Setting: Follow-up of single-center randomized study.Patients: Thirteen patients with obesity andT2D compared to 22 healthy subjects.Interventions: Blood chemistry, adipose biopsies, and heart rate variability were obtained before and 4, 24, and 104 weeks post-RYGB.Results: After RYGB, glucose-lowering drugs were discontinued and hemoglobin A1c fell from mean 55 to 41 mmol/mol by 104 weeks (P < 0.001). At 4 weeks, morning cortisol (P < 0.05) and adrenocorticotropin (P = 0.09) were reduced by 20%. Parasympathetic nerve activity (heart rate variability derived) increased at 4 weeks (P < 0.05) and peaked at 24 weeks (P < 0.01). C-reactive protein (CRP) and white blood cells were rapidly reduced (P < 0.01). At 104 weeks, basal and insulin-stimulated adipocyte glucose uptake increased by 3-fold vs baseline and expression of genes involved in glucose transport, fatty acid oxidation, and adipogenesis was upregulated (P < 0.01). Adipocyte volume was reduced by 4 weeks and more markedly at 104 weeks, by about 40% vs baseline (P < 0.01).Conclusions: We propose this order of events: (1) rapid glucose lowering (days); (2) attenuated cortisol axis activity and inflammation and increased parasympathetic tone (weeks); and (3) body fat and weight loss, increased adipose glucose uptake, and whole-body insulin sensitivity (months-years; similar to healthy controls).Thus, neuroendocrine pathways can partly mediate early glycemic improvement after RYGB, and adipose factors may promote long-term insulin sensitivity and normoglycemia.
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| 4. |
- Andersson, Urban, et al.
(författare)
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Nurses’ experiences of informal coercion on adult psychiatric wards
- 2020
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Ingår i: Nursing Ethics. - : SAGE Publications. - 0969-7330 .- 1477-0989. ; 27:3, s. 741-753
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Tidskriftsartikel (refereegranskat)abstract
- Background:Informal coercion, that is, situations where caregivers use subtle coercive measures to impose their will on patients, is common in adult psychiatric inpatient care. It has been described as ‘a necessary evil’, confronting nurses with an ethical dilemma where they need to balance between a wish to do good, and the risk of violating patients’ dignity and autonomy.Aim:To describe nurses’ experiences of being involved in informal coercion in adult psychiatric inpatient care.Research design:The study has a qualitative, inductive design.Participants and research context:Semi-structured interviews with 10 Swedish psychiatric nurses were analysed with qualitative content analysis.Ethical considerations:The study was performed in accordance with the Declaration of Helsinki. In line with the Swedish Ethical Review Act, it was also subject to ethical procedures at the university.Findings:Four domains comprise informal coercion as a process over time. These domains contain 11 categories focusing on different experiences involved in the process: Striving to connect, involving others, adjusting to the caring culture, dealing with laws, justifying coercion, waiting for the patient, persuading the patient, negotiating with the patient, using professional power, scrutinizing one’s actions and learning together.Discussion:Informal coercion is associated with moral stress as nurses might find themselves torn between a wish to do good for the patient, general practices and ‘house rules’ in the caring culture. In addition, nurses need to be aware of the asymmetry of the caring relationship, in order to avoid compliance becoming a consequence of patients subordinating to nurse power, rather than a result of mutual understanding. Reflections are thus necessary through the process to promote mutual learning and to avoid violations of patients’ dignity and autonomy.Conclusion:If there is a need for coercion, that is, if the coercion is found to be an ‘unpleasant good’, rather than ‘necessary evil’ considering the consequences for the patient, it should be subject to reflecting and learning together with the patient
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| 5. |
- Carlsson, Jenny, 1984-, et al.
(författare)
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Investigating tool engagement in groundwood pulping : finite element modelling and in-situ observations at the microscale
- 2020
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Ingår i: Holzforschung. - : Walter de Gruyter GmbH. - 0018-3830 .- 1437-434X. ; 74:5, s. 477-487
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Tidskriftsartikel (refereegranskat)abstract
- With industrial groundwood pulping processes relying on carefully designed grit surfaces being developed for commercial use, it is increasingly important to understand the mechanisms occurring in the contact between wood and tool. We present a methodology to experimentally and numerically analyse the effect of different tool geometries on the groundwood pulping defibration process. Using a combination of high-resolution experimental and numerical methods, including finite element (FE) models, digital volume correlation (DVC) of synchrotron radiation-based X-ray computed tomography (CT) of initial grinding and lab-scale grinding experiments, this paper aims to study such mechanisms. Three different asperity geometries were studied in FE simulations and in grinding of wood from Norway spruce. We found a good correlation between strains obtained from FE models and strains calculated using DVC from stacks of CT images of initial grinding. We also correlate the strains obtained from numerical models to the integrity of the separated fibres in lab-scale grinding experiments. In conclusion, we found that, by modifying the asperity geometries, it is, to some extent, possible to control the underlying mechanisms, enabling development of better tools in terms of efficiency, quality of the fibres and stability of the groundwood pulping process.
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| 6. |
- Carlsson, Jenny, 1984-
(författare)
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On Crack Dynamics in Brittle Heterogeneous Materials
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Natural variation, sub-structural features, heterogeneity and porosity make fracture modelling of wood and many other heterogeneous and cellular materials challenging. In this thesis, fracture in such complicated materials is simulated using phase field methods for fracture. Phase field methods have shown promise in simulations of complex geometries as well as dynamics and require few additional parameters; only the material toughness and a length parameter, determining the width of a regularised crack, are needed.First, a dynamic phase field model is developed and validated against experiments performed on homogeneous brittle polymeric materials, wood fibre composites and polymeric materials with different hole patterns. Then, a high-resolution model of wood is developed and related to experiments, this time without considering fracture. Attention is finally focussed on high-resolution numerical analyses of fracture in wood and other cellular microstructures, considering both heterogeneity and relative density.The phase field model is found to reproduce crack paths, velocities and energy release rates well in homogeneous samples both with and without holes. In more complicated heterogeneous and porous materials, the model is also able to simulate crack paths, but the interpretation of the length scale is complicated by the inherent lengths of the micro-structural geometry. In sum, the thesis points to possibilities with the proposed method, as well as limitations in our current understanding of both quasistatic and dynamic fracture of heterogeneous and cellular materials. The findings of this thesis can contribute to an improved understanding of fracture in such materials.
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| 7. |
- Erelund, Sofia, et al.
(författare)
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Are ECG changes in heart-healthy individuals of various ages related to cardiac disease 20 years later?
- 2021
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Ingår i: Upsala Journal of Medical Sciences. - : Upsala Medical Society. - 0300-9734 .- 2000-1967. ; 126:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: This research study aimed at assessing the electrocardiographic (ECG) changes caused by ageing in a cohort of healthy subjects with normal echocardiographic examinations.Methods: A total of 219 healthy individuals (119 males and 100 females) were evaluated for possible arrhythmias with a standard 12-lead resting ECG and 24-h Holter ECG. As the recordings were performed between 1998 and 2000, a 20-year follow-up study was carried out by assessing the local medical records to investigate whether the subjects had experienced any cardiovascular health complications or disease since the baseline assessment.Results: Eighty-three subjects (45 males and 38 females) presented with pathological ECG findings at baseline. The most common finding on analysis of Holter ECG recordings was premature atrial contractions, and the most severe pathological finding was episodes of ventricular tachycardia (eight subjects). Regarding the analysis of the standard 12-lead ECG, the most common finding was left ventricular hypertrophy, and the most severe pathological findings were ST-T changes and prolongation of the QT interval. Despite other cardiac examinations performed on these patients showing normal results, in combination with a strict inclusion criterion, this study showed that 28% of all subjects had pathological resting 12-lead ECGs at rest and 35% had pathological heart rhythms when assessed by 24-h Holter ECG. At follow-up, 21% of females and 43% of males had presented with ECG abnormalities, and 30% of females and 36% of males had cardiovascular disease. There was hypertension in 45% of females and in 58% of males. However, no association was found between the follow-up findings and ECG changes seen at baseline.Conclusion: Although most ECG changes found at baseline could be considered as a normal variation, they may progress to more severe heart complications as the subject ages. The results of this study also validate ECG findings of previous studies and underline that diagnostic criteria should be based on gender and age.
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| 8. |
- Goel, Sneha, 1993-, et al.
(författare)
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Axial Plasma Spraying of Mixed Suspensions : A Case Study on Processing, Characteristics, and Tribological Behavior of Al2O3-YSZ Coatings
- 2020
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Ingår i: Applied Sciences. - : MDPI. - 2076-3417. ; 10:15
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Tidskriftsartikel (refereegranskat)abstract
- Thermal spraying deploying liquid feedstock offers an exciting opportunity to obtain coatings with characteristics vastly different from those produced using conventional spray-grade powders. The most extensively investigated variant of this technique is Suspension Plasma Spraying (SPS), which utilizes a suspension of fine powders in an appropriate medium. The relatively recent advent of axial feed capable plasma spray systems can enable higher throughputs during SPS, provides the possibility for spraying with longer stand-off distances, and also permit the use of suspensions with higher solid loading. The present work investigates axial plasma sprayed coatings produced using a mixed suspension of fine (submicron or nano-sized) powders of Al(2)O(3)and YSZ as a case study. Deposition of the mixed suspension using axial injection plasma spraying, comprehensive evaluation of characteristics of the resulting coatings, and assessment of their tribological behavior were of particular interest. Evaluation of surface morphology, microstructure, and hardness of the coatings reveals that axial SPS of mixed suspensions provides an exciting pathway to realize finely structured multi-constituent coatings using suspensions with as high as 40 wt.% solid loading. The study of scratch, dry sliding wear, and erosion behavior also specifically shows that the addition of YSZ in the Al(2)O(3)matrix can improve the tribological properties of the coating.
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| 9. |
- Granåsen, Gabriel, 1980-
(författare)
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Patient stratification and treatment effects in diseases with disturbed cardiac function
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Cardiovascular disease characteristics are often measured using a combination of different measurement modalities. By combining information from these modalities using statistical modelling we can gain additional knowledge about these diseases. Patients with hereditary transthyretin amyloidosis (ATTRv amyloidosis) often present with heart rate disturbances and ventricular hypertrophy. Although ATTRv amyloidosis can lead to a thick ventricular myocardium and heart failure this can also be due to other pathologies e.g. hypertrophic cardiomyopathy (HCM), which may lead to misdiagnosis. Children with hereditary long QT syndrome (LQTS) carry the risk of lethal cardiac events linked to increased sympathetic activity. If the regulatory pattern, measured by heart rate variability (HRV), could differentiate between LQTS genotypes and healthy children during childhood, it may then establish a role for HRV in evaluating such patients. Statins is the most common pharmaceutical treatment for atherosclerosis. However, the effect of statins on coronary calcification has shown mixed results between studies.Aim: The overall aim of this thesis was to use statistically rigorous methodology to explore stratification of subgroups of patients and estimate treatment effects in diseases with cardiac involvement. The specific aims were: to evaluate discriminating features between ATTRv amyloidosis and HCM patients in different clinical examinations of their hearts; to evaluate the longitudinal growth pattern in HRV in children with LQTS; and, to estimate the short- and long-term treatment effects of statin treatment on coronary calcification in patients with coronary arteriosclerosis. Methods: In Study I we used classification and regression trees in order to create a clinical interpretable decision tree in order to differentiate between 35 ATTRv amyloidosis patients and 37 HCM patients based on features derived from echocardiography and ECG. In Study II a retrospective sample of 38 ATTRv amyloidosis patients, 41 HCM patients and 62 healthy controls were analyzed using k-means clustering and Random forest models in order to investigate similarities and differences in echocardiographic features and HRV. In Study III we calculated gender and treatment dependent age trends for spectral HRV features from longitudinal measurements from 70 children with LQTS (58 LQT1, 12 LQT2) and 65 healthy controls, using generalized additive mixed effects models. In Study IV data from two large clinical trials, in total 1585 patients with mild cardiac symptoms, was used to estimate the short- and long-term treatment effects of statin treatment on coronary calcification.Results: In study I we found that a decision tree using both ECG and echocardiographic measurements provided the best separation between HCM and ATTRv amyloidosis. In study II we found that HRV could be used for discriminating between these diseases and that abnormalities in HRV are related on ATTRv fibril type but uncommon in HCM. In study III we found that the age trend in HRV in LQTS-patients showed no clear differences between controls and patients different LQTS genotypes. In study IV we found that high dose statin treatment resulted in a dose dependent increase in calcium score at both short- and long-term follow up. At the long-term follow up, we found no evidence to suggest that the increased calcium score had resulted in increased cardiac events.Conclusions: The results from our studies could be used for differentiating HCM and ATTRv amyloidosis patients. The heterogeneity within these patient groups could further be characterized using features from echocardiography and HRV. Our data do not support evidence for a different age trend in HRV parameters in children with LQTS compared to controls of similar age. We also found that statin treatment increased calcium score on both short-and long-term follow up. Taken together the results and methods from this thesis may be used for future support in clinical decisions regarding patient stratification and knowledge of treatment effects.
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| 10. |
- Hallingbäck, Tomas, et al.
(författare)
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Rödlista över mossor - Bryophyta
- 2020. - 2020
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Ingår i: Rödlistade arter i Sverige 2020. - 9789187853548 - 9789187853555 ; , s. 59-66
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Bokkapitel (refereegranskat)
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