| 1. |
- Hannuksela, Matias, 1969-
(author)
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Familial thoracic aortic aneurysms and dissections : studies on genotype and phenotype
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Background: Thoracic aortic aneurysms and dissections (TAAD) have a genetic component with an estimated 20-25% of the patients having a positive family history. An aneurysm often precedes a dissection. Acute aortic dissections are associated with high mortality and morbidity, even when operated on. Complications due to prophylactic surgery are considerably fewer. Therefore, patients at risk for dissection should be identified, followed-up and evaluated for prophylactic intervention.Aims: 1. To establish reference values for ascending (AoA) and descending aortic (AoD) diameters measured by computed tomography. 2. To study the effectiveness of phenotypic cascade screening in families with an inherited form of thoracic aortic aneurysms and dissections (FTAAD) and to address questions that arise when screening for a genetic disorder is applied. 3. To study the agreement of aortic diameters obtained by TTE and MRI and to study aortic stiffness in individuals from families with FTAAD. 4. To perform exome sequencing in order to identify pathogenic sequence variants causing FTAAD, to characterize the phenotype, and to compare thoracic aortic diameter and stiffness in mutation carriers and non-carriers.Results: Paper I: The diameter of the thoracic aorta increased by 0.17 mm (0.12 – 0.20 mm) per year. The mean sex-related difference in diameter was 1.99 mm (1.28 – 2.60 mm) with men having larger aortas than women. The mean difference in aortic diameter per unit BMI was 0.27 mm (0.14 – 0.44 mm). Upper normal limits for the AoA can be calculated by the formula D (mm)=31+0.16*age and for the AoD by D (mm)=21+0.16*age.Paper II: Of 106 individuals from families with FTAAD but without known thoracic aortic disease, 19 individuals (18%) were identified to have a dilated AoA. The expected number of individuals in this group with an autosomal dominant disease would have been 40 (p<0.0001). In first-degree relatives younger than 40, we found only one individual with a dilated aorta although the expected number of individuals with disease causing mutation would have been 10.Paper III: Of 116 individuals investigated, 21 were identified with thoracic aortic dilatation and 95 individuals with normal thoracic aortic diameter. Aortic stiffness increased with age and diameter. The individuals with aortic dilatation were older than those without (49 vs. 37 years, p=0.001) and showed lower aortic elastic properties. The diameters measured by TTE and MRI correlated strongly (r2=0.93). The mean difference in diameters between the two methods was 0.72 mm (95% CI 0.41-1.02) with TTE giving larger diameters than MRI.Paper IV: From exome sequencing and segregation analysis, a 2-bp deletion in the MYLK gene (c.3272_3273del) was identified to cause FTAAD. The age and the aortic diameter at dissection or rupture varied in the family members. We did not find any differences in aortic diameter, aortic stiffness, or pulse wave velocity between carriers and non-carriers.Conclusions: Thoracic aortic diameter increases with age, and sex and body size are also associated with the diameter. In FTAAD, screening identifies family members with a previously unknown aortic dilatation. However, a normal aortic diameter does not exclude an individual from being a carrier of FTAAD. TTE can be used in follow-up for the ascending aorta. Individuals identified to have a dilated thoracic aorta have increased aortic stiffness compared to individuals with normal thoracic aortic diameter. The MYLK mutation (c.3272_3273del) causes thoracic aortic dissections with variable clinical expression. No differences in aortic stiffness were identified between MYLK mutation carriers and non-carriers.
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| 2. |
- Johansson, F., et al.
(author)
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3D-thermal modelling of a bifacial agrivoltaic system: a photovoltaic module perspective
- 2022
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In: Energy Nexus. - : Elsevier BV. - 2772-4271. ; 5
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Journal article (peer-reviewed)abstract
- This study presents a 3D computational fluid dynamic model to evaluate the temperature distribution and energy performances of a vertical bifacial photovoltaic module for agrivoltaic applications. This last is compared to a conventionally tilted bifacial photovoltaic module for ground-mounted applications. The simulations are performed in SolidWorks Flow Simulation® and validated with measured data gathered from the first experimental agrivoltaic system in Sweden. Additionally, four more simulations scenarios were defined to compare the performances of vertically mounted and conventionally tilted bifacial photovoltaic modules under different operating conditionsThe validation of the computational fluid dynamic model shows that the model tends to underestimate the readings performed with the thermal camera in the order of 3°C to 4°C for the vertical bifacial PV module. The comparison of the results obtained from the computational fluid dynamic model with existing models available in literature shows a good agreement. The comparison of the heat distribution from the computational fluid dynamic model and the thermal images also shows a good agreement. In all the scenarios investigated, the vertical bifacial photovoltaic module's overall efficiency was higher than that of the ground-mounted module due to lower average operating temperatures. The use of the computational fluid dynamic approach for studying the performance of a single photovoltaic module showed promising results that can be extended to study the system performance and microclimatic conditions.
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| 3. |
- Johansson, Karna, 1982-
(author)
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Altered body composition in adults with complex congenital heart disease
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Introduction: Thanks to achievements in paediatric heart surgery and medicine, the population of adults with surgically repaired or palliated congenital heart defects is growing. Many of these adults have reduced exercise capacity, weaker muscular strength and shorter height, all of which suggest an altered body composition.The overall aim of this thesis was to evaluate the body composition, in terms of bone, muscle and fat mass, in adults with complex congenital heart disease (CHD). Changes as such may be of prognostic importance and thus suggest future therapeutic targets outside the traditional hunting grounds of the cardiologist.Material and methods: The overall material consisted of two cohorts. The first cohort, recruited in a Swedish multicentre study, comprised 73 adult patients with complex CHD and 73 controls, matched for age and sex. Participants were examined with full body dual-energy x-ray absorptiometry (DXA), providing muscle, bone and fat mass for arms, legs and trunk respectively (papers I and II).The second cohort, recruited within a single centre study, comprised 49 adult patients with complex CHD and 49 age and sex matched controls. Participants were examined with peripheral quantitative computed tomography (pQCT), providing slices of forearm and calf, describing muscle, bone and fat area and corresponding density (papers III and IV). Muscular strength in selected muscle groups was also evaluated in both cohorts.Results: More than half of the adults with complex CHD had a pathologically low skeletal muscle mass and strength compared to controls, a trait referred to as sarcopenia. There was a strong association between forearm muscle mass and grip strength.Bone mass was lower in adults with complex CHD, according to both DXA and pQCT analyses, also when adjusting for shorter height. Patients also had lower full body bone mineral density (BMD) as measured with DXA. However, analysis of BMD in limbs with pQCT showed no such reduction. Despite this latter finding, the strength-strain index (a surrogate marker for bone strength provided by pQCT in the lower limbs) was still lower in patients compared to controls.Female patients had a higher amount of fat, both in terms of fat mass and proportion of fat, in comparison to controls. The fat mass was predominantly distributed around the internal organs, known as visceral adipose tissue. Male patients showed no such difference regarding fat mass compared to controls.Conclusion: Consequences of living with complex CHD go far beyond the heart; this young population presents a reduced skeletal muscle mass as well as reduced bone strength – both premature traits of frailty, prone to increase with further ageing. Also, women with complex CHD have an increased amount of visceral adipose tissue, which may elevate the risk of acquired heart disease.The extent of future complications remains to be seen. However, the standard treatments for both sarcopenia and osteoporosis include optimal nutritional intake and increased physical exercise. These measures should start sooner rather than later, preferably evaluated through existing quality registers and interventional trials.
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| 4. |
- Thalén-Lindström, Annika
(author)
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Screening and Assessment of Distress, Anxiety, and Depression in Cancer Patients
- 2014
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Doctoral thesis (other academic/artistic)abstract
- Aims and Methods The overall aim was to evaluate methods of screening and assessment of distress, anxiety, and depression in cancer patients. Further, to evaluate effects of a psychosocial intervention and to explore changes of distress, anxiety, depression, and HRQoL during six months. Study I included 495 consecutive patients screened with the Hospital Anxiety and Depression Scale (HADS) at their first visit to an Oncology Department. Half of the patients with >7 on any of HADS subscales received standard care (SCG), and half received a psychosocial intervention (IG). To compare HADS with a thorough clinical assessment (CA), Study II included 171 identified patients representing both sexes, <65/≥65 years, and curative/palliative treatment intention.Results Screening with HADS identified anxiety or/and depression symptoms in 36% of the 495 patients. Thirty-six (43%) of 84 IG patients attended CA, resulting in support for 20 (24%) of them. There were no differences between SC and IG during follow-up, anxiety and depression decreased and HRQoL increased, although anxiety was still present and HRQoL impaired at six months. The Distress Thermometer (DT) ≥4 (sensitivity 87%, specificity 73%) is valid for screening of distress; its ability to measure changes over time is comparable to HADS. Of 319 patients screened with <8 on both HADS subscales, 196 (80%) were stable non-cases with HRQoL comparable to that of the general population and 49 (20%) patients were unstable non-cases, with deteriorated anxiety, depression, and HRQoL. >4 on HADS subscales may be useful for early detection of unstable non-cases. In Study II, HADS identified 49 (34%) and the CA 71 (49%) patients as having distress, anxiety or depression. CA identified more men and more young patients with distress than HADS did.Conclusion Screening and assessment identifies patients with persistent symptoms and increases access to CA and support. The DT may be used routinely in oncology care. When HADS is used, healthcare professionals should be aware of psychosocial problems perceived by patients but not covered by HADS. Most patients identified with distress seem to have resources to manage problems without needing additional support. Patients screened as non-cases indicate no need for re-assessment.
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