DIC for Surface Motion Analysis Applied to Displacement of a Stent Graft for Abdominal Aortic Repair in a Pulsating Flow

Stent graft migration has been recognized to influence the long-term durability of endovascular aortic repair. Flow-induced displacement forces acting on the attachment zones may contribute to this migration. An experimental perfusion model consisting of the flow loop described by Roos et al. 2014 was used for further characterization of the pulsating flow induced stent graft movements with monocular and stereoscopic configurations of an optical imaging system. This paper adds new information on displacement measurement accuracy and 3D deformation analysis of the stent graft, which is used for abdominal aortic aneurysm treatment. The work describes used modification of Soloff’s Stereo PIV reconstruction algorithm for surface motion analysis. It was found that the oscillation of the stent graft’s body in the perpendicular direction to the front plane was 5 times less than side movements of the bent stent graft. These results can be used for further studies on different stent graft geometrical configurations and CFD simulations using fluid-structure interaction approach

Serum concentrations of phthalate metabolites are related to abdominal fat distribution two years later in elderly women

BACKGROUND: Phthalates, commonly used to soften plastic goods, are known PPAR-agonists affecting lipid metabolism and adipocytes in the experimental setting. We evaluated if circulating concentrations of phthalates were related to different indices of obesity using data from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Data from both dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) were used. METHODS: 1,016 subjects aged 70 years were investigated in the PIVUS study. Four phthalate metabolites were detected in the serum of almost all subjects (> 96%) by an API 4000 liquid chromatograph/tandem mass spectrometer. Abdominal MRI was performed in a representative subsample of 287 subjects (28%), and a dual-energy X-ray absorptiometry (DXA)-scan was obtained in 890 (88%) of the subjects two year following the phthalate measurements. RESULTS: In women, circulating concentrations of mono-isobutyl phthalate (MiBP) were positively related to waist circumference, total fat mass and trunk fat mass by DXA, as well as to subcutaneous adipose tissue by MRI following adjustment for serum cholesterol and triglycerides, education, smoking and exercise habits (all p < 0.008). Mono-methyl phthalate (MMP) concentrations were related to trunk fat mass and the trunk/leg-ratio by DXA, but less powerful than MiBP. However, no such statistically significant relationships were seen in men. CONCLUSIONS: The present evaluation shows that especially the phthalate metabolite MiBP was related to increased fat amount in the subcutaneous abdominal region in women measured by DXA and MRI two years later

Alcohol Consumption, Cigarette Smoking, and Risk of Breast Cancer for BRCA1 and BRCA2 Mutation Carriers: Results from The BRCA1 and BRCA2 Cohort Consortium.

BACKGROUND: Tobacco smoking and alcohol consumption have been intensively studied in the general population to assess their effects on the risk of breast cancer, but very few studies have examined these effects in BRCA1 and BRCA2 mutation carriers. Given the high breast cancer risk for mutation carriers and the importance of BRCA1 and BRCA2 in DNA repair, better evidence on the associations of these lifestyle factors with breast cancer risk is essential. METHODS: Using a large international pooled cohort of BRCA1 and BRCA2 mutation carriers, we conducted retrospective (5,707 BRCA1 mutation carriers and 3,525 BRCA2 mutation carriers) and prospective (2,276 BRCA1 mutation carriers and 1,610 BRCA2 mutation carriers) analyses of alcohol and tobacco consumption using Cox proportional hazards models. RESULTS: For both BRCA1 and BRCA2 mutation carriers, none of the smoking-related variables was associated with breast cancer risk, except smoking for more than 5 years before a first full-term pregnancy (FFTP) when compared with parous women who never smoked. For BRCA1 mutation carriers, the HR from retrospective analysis (HRR) was 1.19 [95% confidence interval (CI), 1.02-1.39] and the HR from prospective analysis (HRP) was 1.36 (95% CI, 0.99-1.87). For BRCA2 mutation carriers, smoking for more than 5 years before an FFTP showed an association of a similar magnitude, but the confidence limits were wider (HRR = 1.25; 95% CI, 1.01-1.55 and HRP = 1.30; 95% CI, 0.83-2.01). For both carrier groups, alcohol consumption was not associated with breast cancer risk. CONCLUSIONS: The finding that smoking during the prereproductive years increases breast cancer risk for mutation carriers warrants further investigation. IMPACT: This is the largest prospective study of BRCA mutation carriers to assess these important risk factors

Re-interventions after endovascular aortic repair: clinical and experimental studies

Background: Endovascular aortic repair (EVAR) has lower morbidity and mortality than open surgery. Late complications and re-interventions are more common, however, and the timing of different re-interventions and their respective underlying causes are not fully understood. Aims: The overall aim was to describe re-interventions after EVAR and to identify possible underlying causes. Specific aims were as follows: 1. To describe re-interventions after EVAR, including incidence, indications, procedures, and outcome, concentrating especially on non-access-related re-interventions. 2. To determine underlying causes and to identify anatomical factors associated with additional iliac stent grafting. 3. To study flow-induced displacement forces in iliac limb stent grafts and the influence of stent graft angulation, fluid pressure, pulsation frequency, distal diameter of the stent graft, and asymmetric graft curvatures in an experimental aortic model. 4. To describe a new endovascular technique to close small entries that persist in the aortic arch. Materials and methods: Studies 1 and 2 were retrospective single-centre cohort studies of re-interventions after standard EVAR, focusing especially on non-access-related re-interventions. In Study 1, incidence, indications, procedures, and outcome were analyzed in 405 patients. In Study 2, 24 patients with additional iliac stent grafts after EVAR were studied. Computed tomography examinations were reviewed in detail regarding causes of re-intervention and underlying anatomic factors. These patients were compared with 420 patients treated with bifurcated EVAR during the same time period who did not require additional iliac stent grafts during follow-up, regarding patient characteristics and preoperative anatomic measurements. Studies 3 and 4 involved investigation of flow-induced displacement forces in iliac limb stent grafts in an experimental flow model mimicking physiologic conditions. In Study 3, the forces on a tubular stent graft with symmetric curvature were studied in relation to graft angulation, fluid pressure, and stroke rate. In Study 4 tapered, non-tapered, and bell-bottom grafts were studied at symmetric graft curvature and non-tapered grafts were studied at asymmetric curvature. Study 5 involved a new endovascular technique for closure of persistent small entries in selected patients with aneurysmal dilatation of chronic aortic dissections. Results: Study 1 showed that embolization of endoleak type II and placement of additional iliac stent grafts were the most common re-interventions after EVAR. These interventions were performed long after the initial intervention. Medium-term outcome in patients with re-intervention was comparable to that in patients without re-intervention. Study 2 showed that a considerable number of additional iliac stent grafting were caused by rupture. Migration at the distal landing site or graft interconnections was the most common cause, followed by disease progression. Study 3 demonstrated that flow-induced displacement forces were of similar magnitude at both ends of a non-tapered iliac stent graft, and the force increased with increasing graft angulation and fluid pressure but not with increasing pulse frequency. There was a high correlation between pulsatile graft movement and displacement forces. Study 4 showed that there were particularly high displacement forces in bell-bottom grafts, and that the forces were dependent on distal graft diameter and shape of the curvature. Study 5 showed that endovascular closure of persistent entries in chronic dissections is feasible, and in selected patients it may be an alternative to open surgery. Conclusions: Re-interventions are still common after EVAR, but most are percutaneous procedures and outcomes are generally good. Additional iliac stent grafting is one of the more frequent re-interventions, and in most cases it is related to stent graft migration, with a higher risk in patients with large iliac diameters and short attachment zones. Flow-induced displacement forces may have a role in the increased risk of migration. Patients with EVAR landing zones in wide iliac arteries may need improved graft fixation and more vigorous surveillance

Physical Planning of ASIC’s in mobile systems

With increasing demands in terms of timing, area and power, today’s ASIC (Application Specific Integrated Circuit) designers are faced with new problems as technology emerges. Ericsson has started to work in 65 nm and realized that the methods used in previous, larger technologies, does not offer good enough correlation between synthesis and the results after physical placement. This leads to several expensive and time consuming iterations back and forth between Ericsson and the ASIC vendor. In order to narrow the gap between Ericsson and the ASIC vendor, and hence increase correlation, physical planning has been identified as a possible solution. Cadence First Encounter, part of the Cadence Encounter digital IC design platform, is an advanced tool for silicon virtual prototyping. The tool basically brings back-end placement knowledge to front-end ASIC designers. This master’s thesis main goal is to evaluate Cadence First Encounter and investigate how it could be integrated with Ericsson’s design flow. The tool has been tested on previous designs with known issues and the results are positive. By using the prototype work flow in First Encounter that is described in this report, it is possible to identify and correct issues with the netlists in time, which will help shortening the lead time in projects and hence also the time to market

Fluid pressure derived force is the main contributor to iliac limb displacement forces – shear force and redirection of flow are negligible

Introduction -\ua0Complications after EVAR, including aortic rupture, continue to be a problem also in long term follow-up1. There is still a need for life-long surveillance and late re-interventions raises the question about long term EVAR-durability. Additional iliac stent grafts due to distal endoleak type I are among the more frequent among these late re-interventions2,3,4. There are indications that graft migration at iliac landing zones and graft interconnections are among the most common causes and that wide iliac arteries predispose for these complications5. Flow induced displacement forces have, in an experimental model, been shown to be significant also at distal landing zones in EVAR stent grafts6\ua0and particularly high in grafts with large distal diameters7. These findings indicate that late EVAR failures are linked to flow induced displacement forces and subsequent graft migration. We have therefore conducted a study of fluid structure interaction with the aim to differentiate the magnitude of the different force components and numerically evaluate the forces acting on iliac limb stent grafts in different graft configurations.Methods -\ua0The displacement forces in iliac limb stent grafts were numerically evaluated using a finite volume approach for fluid-structure interaction (FSI) with the open source tool FOAM-extend-3.1. The grafts were modelled with homogeneous properties in three configurations; tapered (16 mm proximal diameter, 12 mm distal diameter), non tapered (16-16 mm) and bellbottom (16-27 mm), all at 90\ub0 angulation (see 16-27 in figure). Experimentally determined pulsatile conditions were applied for different pressures; 145/80, 170/90, 195/100 mmHg.Results -\ua0Stent graft displacement forces increased with higher fluid pressure in all graft configurations. Maximum forces in bellbottom grafts (proximal end 2.3 N, distal end 8.1 N) were particularly high compared to tapered (proximal end 2.5 N, distal end 1.2 N) and non tapered grafts (proximal end 2.5 N, distal end 2.5 N). The effects of shear stress and redirection of flow were together less than 2.8 % of the total forces in all graft configurations, whereas pressure derived forces were the main contributor to the forces acting on the stent graft. The flexibility of the stent graft absorbed up to 15 % of the forces.Conclusion -\ua0The forces acting on stent grafts during pulsatile flow are significant and particularly high in the distal end of grafts with large distal diameter. The main contributor to these displacement forces is pressure while the contribution of shear and redirection of flow are negligible. The flexibility of the stent graft tends to absorb a significant part of the forces

Kvinnor och missbruk : En teoretisk uppsats om kvinnors missbruk av alkohol och droger

The aim of this study was, with a theoretical approach, to examine women’s alcohol- and drug problems. Our questions at issues considered early debut, heredity and environment as well as which factors can explain women’s use of alcohol and drugs. This study is based on 5 international published articles, Swedish literature and reports and a minor questionnaire meant to be at help in our analysis of the material. We examine our material with the control theory, the social learning theory, the masculinity theory and developmental psychological theory. Research shows an increase in young women’s alcohol and drug abuse and possible reasons are increase of media exposure, changed gender roles, sexual abuse, stress and mental health problems and social marginalization. Our questionnaire shows similar results as earlier research. We found that peers and boyfriends influenced the women in our study in their early onset and that heredity and environment also is pertinent factors for developing abuse of drugs and alcohol. For the women in our study, there seems to be a lack of protective factors which researchers find important. On the contrary, there seemed to be several numbers of risk factors who could explain the women’s development of alcohol and drug abuse. Keywords: Abuse, addict, adolescence, alcohol, drugs, drug misuse and women

Kvinnor och missbruk : En teoretisk uppsats om kvinnors missbruk av alkohol och droger

The aim of this study was, with a theoretical approach, to examine women’s alcohol- and drug problems. Our questions at issues considered early debut, heredity and environment as well as which factors can explain women’s use of alcohol and drugs. This study is based on 5 international published articles, Swedish literature and reports and a minor questionnaire meant to be at help in our analysis of the material. We examine our material with the control theory, the social learning theory, the masculinity theory and developmental psychological theory. Research shows an increase in young women’s alcohol and drug abuse and possible reasons are increase of media exposure, changed gender roles, sexual abuse, stress and mental health problems and social marginalization. Our questionnaire shows similar results as earlier research. We found that peers and boyfriends influenced the women in our study in their early onset and that heredity and environment also is pertinent factors for developing abuse of drugs and alcohol. For the women in our study, there seems to be a lack of protective factors which researchers find important. On the contrary, there seemed to be several numbers of risk factors who could explain the women’s development of alcohol and drug abuse. Keywords: Abuse, addict, adolescence, alcohol, drugs, drug misuse and women