| 1. |
|
|
| 2. |
|
|
| 3. |
- Chen, Ding Yuan, et al.
(författare)
-
Microwave Performance of 'Buffer-Free' GaN-on-SiC High Electron Mobility Transistors
- 2020
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 41:6, s. 828-831
-
Tidskriftsartikel (refereegranskat)abstract
- High performance microwave GaN-on-SiC HEMTs are demonstrated on a heterostructure without a conventional thick doped buffer. The HEMT is fabricated on a high-quality 0.25~\boldsymbol {\mu }\text{m} unintentional doped GaN layer grown directly on a transmorphic epitaxially grown AlN nucleation layer. This approach allows the AlN-nucleation layer to act as a back-barrier, limiting short channel effects and removing buffer leakage. The devices with the 'buffer-free' heterostructure show competitive DC and RF characteristics, as benchmarked against the devices made on a commercial Fe-doped epi-wafer. Peak transconductances of 500 mS/mm and a maximum saturated drain current of 1 A/mm are obtained. An extrinsic \text{f}-{\sf T} of 70 GHz and \text{f}-{\sf max} of 130 GHz are achieved for transistors with a gate length of 100 nm. Pulsed-IV measurements reveal a lower current slump and a smaller knee walkout. The dynamic IV performance translates to an output power of 4.1 W/mm, as measured with active load-pull at 3 GHz. These devices suggest that the 'buffer-free' concept may offer an alternative route for high frequency GaN HEMTs with less electron trapping effects.
|
|
| 4. |
- Ekblom Bak, Elin, 1981-, et al.
(författare)
-
Accelerometer derived physical activity patterns in 27.890 middle‐aged adults : The SCAPIS cohort study
- 2022
-
Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : John Wiley & Sons. - 0905-7188 .- 1600-0838. ; 32:5, s. 866-880
-
Tidskriftsartikel (refereegranskat)abstract
- The present study aims to describe accelerometer-assessed physical activity (PA) patterns and fulfillment of PA recommendations in a large sample of middle-aged men and women, and to study differences between subgroups of socio-demographic, socio-economic, and lifestyle-related variables. A total of 27 890 (92.5% of total participants, 52% women, aged 50–64 years) middle-aged men and women with at least four days of valid hip-worn accelerometer data (Actigraph GT3X+, wGT3X+ and wGT3X-BT) from the Swedish CArdioPulmonary bioImage Study, SCAPIS, were included. In total, 54.5% of daily wear time was spent sedentary, 39.1% in low, 5.4% in moderate, and only 0.1% in vigorous PA. Male sex, higher education, low financial strain, born in Sweden, and sedentary/light working situation were related to higher sedentary time, but also higher levels of vigorous PA. High BMI and having multiple chronic diseases associated strongly with higher sedentary time and less time in all three PA intensities. All-year physically active commuters had an overall more active PA pattern. The proportion fulfilling current PA recommendations varied substantially (1.4% to 92.2%) depending on data handling procedures and definition used. Twenty-eight percent was defined as having an “at-risk” behavior, which included both high sedentary time and low vigorous PA. In this large population-based sample, a majority of time was spent sedentary and only a fraction in vigorous PA, with clinically important variations between subgroups. This study provides important reference material and emphasizes the importance of a comprehensive assessment of all aspects of the individual PA pattern in future research and clinical practice.
|
|
| 5. |
- Gummesson, Anders, 1973, et al.
(författare)
-
Non-alcoholic fatty liver disease is a strong predictor of coronary artery calcification in metabolically healthy subjects: A cross-sectional, population-based study in middle-aged subjects
- 2018
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:8
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives This study aims to estimate the relationship between non-alcoholic fatty liver disease (NAFLD) and measures of atherosclerotic cardiovascular disease (ASCVD), and to determine to what extent such relationships are modified by metabolic risk factors. The study was conducted in the population-based Swedish CArdioPulmonary bioImage Study (SCAPIS) pilot cohort (n = 1015, age 50-64 years, 51.2% women). NAFLD was defined as computed tomography liver attenuation <= 40 Hounsfield Units, excluding other causes of liver fat. Coronary artery calcification score (CACS) was assessed using the Agatston method. Carotid plaques and intima media thickness (IMT) were measured by ultrasound. Metabolic status was based on assessments of glucose homeostasis, serum lipids, blood pressure and inflammation. A propensity score model was used to balance NAFLD and non NAFLD groups with regards to potential confounders and associations between NAFLD status and ASCVD variables in relation to metabolic status were examined by logistic and generalized linear regression models. NAFLD was present in 106 (10.4%) of the subjects and strongly associated with obesity-related traits. NAFLD was significantly associated with CACS after adjustment for confounders and metabolic risk factors (OR 1.77, 95% CI 1.07-2.94), but not with carotid plaques and IMT. The strongest association between NAFLD and CACS was observed in subjects with few metabolic risk factors (n = 612 [60% of all] subjects with 0-1 out of 7 predefined metabolic risk factors; OR 5.94, 95% CI 2.13-16.6). NAFLD was independently associated with coronary artery calcification but not with measures of carotid atherosclerosis in this cohort. The association between NAFLD and CACS was most prominent in the metabolically healthy subjects.
|
|
| 6. |
- Hagberg, Eva, et al.
(författare)
-
Semi-supervised learning with natural language processing for right ventricle classification in echocardiography—a scalable approach
- 2022
-
Ingår i: Computers in Biology and Medicine. - : Elsevier BV. - 0010-4825 .- 1879-0534. ; 143
-
Tidskriftsartikel (refereegranskat)abstract
- We created a deep learning model, trained on text classified by natural language processing (NLP), to assess right ventricular (RV) size and function from echocardiographic images. We included 12,684 examinations with corresponding written reports for text classification. After manual annotation of 1489 reports, we trained an NLP model to classify the remaining 10,651 reports. A view classifier was developed to select the 4-chamber or RV-focused view from an echocardiographic examination (n = 539). The final models were two image classification models trained on the predicted labels from the combined manual annotation and NLP models and the corresponding echocardiographic view to assess RV function (training set n = 11,008) and size (training set n = 9951. The text classifier identified impaired RV function with 99% sensitivity and 98% specificity and RV enlargement with 98% sensitivity and 98% specificity. The view classification model identified the 4-chamber view with 92% accuracy and the RV-focused view with 73% accuracy. The image classification models identified impaired RV function with 93% sensitivity and 72% specificity and an enlarged RV with 80% sensitivity and 85% specificity; agreement with the written reports was substantial (both κ = 0.65). Our findings show that models for automatic image assessment can be trained to classify RV size and function by using model-annotated data from written echocardiography reports. This pipeline for auto-annotation of the echocardiographic images, using a NLP model with medical reports as input, can be used to train an image-assessment model without manual annotation of images and enables fast and inexpensive expansion of the training dataset when needed. © 2022
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Hjelmgren, Ola, et al.
(författare)
-
A study of plaque vascularization and inflammation using quantitative contrast-enhanced US and PET/CT
- 2014
-
Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 83:7, s. 1184-1189
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Contrast-enhanced ultrasound (CEUS) is an in vivo methodology to quantify carotid plaque vascularization. Increased metabolism in plaques, measured as FDG uptake in PET/CT examination, has been associated with markers of inflammation in histological samples. In this study, we tested the association between FDG uptake and vascularization measured by CEUS to assess whether CEUS can be used as an in vivo marker of plaque vulnerability. Methods: After informed consent, subjects aged >60 years with carotid plaque height exceeding 2.5 mm were recruited. CEUS was performed and analyzed using earlier described protocol and software, Contrast Quantification Program, which calculates the fraction of the plaque being contrast positive (CQP value). PET/CT examination was performed within 3 months of CEUS (median time 7 days). PET/CT images were acquired 90 min after FDG injection (2.7 MBq/kg). FDG uptake was measured as tissue background index (TBI), calculated using Spearman's rho as mean standard uptake value (SUV) of the plaque divided by mean Shy in the jugular vein (mean of 7 measuring points). Local ethics committee approved the study. Results: We recruited 13 subjects (5 women) with a mean age of 71 years, 6 had a history of stroke or TIA, 1 had a history of ipsilateral stroke. CQP values showed a significant, positive correlation with TBI of carotid plaques, r= 0.67, p <0.02. Conclusions: Plaque vascularization measured by CEUS correlates positively with FDG uptake measured by PET/CT in humans. This indicates an association between vascularization and inflammation and/or hypoxia, supporting the use of CEUS as a non-invasive method to detect plaque vulnerability. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Malinovschi, Andrei, 1978-, et al.
(författare)
-
Consequences of Using Post- or Prebronchodilator Reference Values in Interpreting Spirometry
- 2023
-
Ingår i: American Journal of Respiratory and Critical Care Medicine. - : American Thoracic Society. - 1073-449X .- 1535-4970. ; 208:4, s. 461-471
-
Tidskriftsartikel (refereegranskat)abstract
- RATIONALE: Post-bronchodilator (BD) spirometry is used for diagnosis of chronic obstructive pulmonary disease (COPD). However, pre-BD reference values are used for spirometry interpretation.OBJECTIVES: To compare the resulting prevalence rates of abnormal spirometry and study the consequences of using pre- or post-BD reference values generated within the Swedish CArdioPulmonary bioImage Study (SCAPIS) when interpreting post-BD spirometry in a general population.METHODS: SCAPIS reference values for post-BD and pre-BD spirometry were based on 10,156 and 1,498 never-smoking, healthy participants, respectively. We studied the associations of abnormal spirometry, defined by using pre- or post-BD reference values, with respiratory burden in the SCAPIS general population (28,851 individuals).MEASUREMENTS AND MAIN RESULTS: Bronchodilation resulted in higher predicted median and lower limit of normal (LLN) for FEV1/FVC ratio. The prevalence of post-BD FEV1/FVC < pre-bronchodilator LLN was 4.8% and that of post-BD FEV1/FVC < post-bronchodilator LLN was 9.9% for the general population. An additional 5.1% was identified as having an abnormal post-BD FEV1/FVC ratio and this group had more respiratory symptoms, emphysema (13.5% vs. 4.1%, p<0.001) and self-reported physician-diagnosed COPD (2.8% vs. 0.5%, p<0.001) than subjects with post-BD FEV1/FVC ratio > LLN for both pre- and post-bronchodilation).CONCLUSIONS: Pre- and post-bronchodilator spirometry reference values differ with regard to FEV1/FVC ratio. Use of post-bronchodilator reference values doubled the population prevalence of airflow obstruction; this was related to a higher respiratory burden. Using post-bronchodilator reference values when interpreting post-bronchodilator spirometry might enable identification of individuals with mild disease and be clinically relevant.
|
|
| 13. |
- Malmros, Anna, 1977, et al.
(författare)
-
Enhanced Mobility in InAlN/AlN/GaN HEMTs Using a GaN Interlayer
- 2019
-
Ingår i: IEEE Transactions on Electron Devices. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1557-9646 .- 0018-9383. ; 66:7, s. 2910-2915
-
Tidskriftsartikel (refereegranskat)abstract
- © 1963-2012 IEEE. An enhancement of the electron mobility ( \mu ) in InAlN/AlN/GaN heterostructures is demonstrated by the incorporation of a thin GaN interlayer (IL) between the InAlN and AlN. The introduction of a GaN IL increases \mu at room temperature (RT) from 1600 to 1930 cm2/Vs. The effect is further enhanced at cryogenic temperature (5 K), where the GaN IL sample exhibits a \mu of 16000 cm2/Vs, compared to 6900 cm2/Vs without IL. The results indicate the reduction of one or more scattering mechanisms normally present in InAlN/AlN/GaN heterostructures. We propose that the improvement in \mu is either due to the suppression of fluctuations in the quantum well subband energies or to reduced Coulomb scattering, both related to compositional variations in the InAlN. HEMTs fabricated on the GaN IL sample demonstrate larger improvement in dc-and high-frequency performance at 5 K; {f}-{\text {max}} increases by 25 GHz to 153 GHz, compared to an increase of 6 GHz to 133 GHz without IL. The difference in improvement was associated mainly with the drop in the access resistances.
|
|
| 14. |
- Olson, Fredrik J., 1975, et al.
(författare)
-
Increased vascularization of shoulder regions of carotid atherosclerotic plaques from patients with diabetes.
- 2011
-
Ingår i: Journal of vascular surgery. - : Elsevier BV. - 1097-6809 .- 0741-5214. ; 54:5
-
Tidskriftsartikel (refereegranskat)abstract
- Increased vascularization is considered an important contributing factor for plaque vulnerability. Microvascular proliferative disease in patients with diabetes results in renal damage and visual loss. We assessed the hypothesis that vascularization in carotid atherosclerotic tissue is increased in diabetic patients, especially in the critical shoulder regions of the plaque.
|
|
| 15. |
- Ragnarson Tennvall, Gunnel, et al.
(författare)
-
Annual costs of treatment for venous leg ulcers in Sweden and the United Kingdom
- 2005
-
Ingår i: Wound Repair and Regeneration. - : Wiley. - 1524-475X .- 1067-1927. ; 13:1, s. 13-18
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to estimate costs of treating venous leg ulcers in Sweden and the United Kingdom during 1 year and to quantify costs in different health states, The costs of treating four different types of venous leg ulcers were estimated for 52 weeks by a stochastic health economic model, which simulated resource use data obtained from prospectively collected patient data, expert panels in the two countries, and published scientific. literature, The average cost of treating an ulcer varied between E 1332 and E2585 in Sweden and from E814 to E1994 in the United Kingdom. Cost of treating large ulcers (greater than or equal to10 cm(2)) of long duration (greater than or equal to6 months) was highest in both countries. Frequency of dressing changes and duration of time for each dressing change were higher in Sweden than in the United Kingdom, resulting in higher total cost per patient in Sweden. An important factor for the total costs was time to heal. Other important variables influencing treatment costs were frequency and duration of dressing changes, Actions to reduce time used for dressing changes and the total time to healing are thus very important in reducing costs spent on treatment of venous leg ulcers in both countries.
|
|
