| 1. |
- Blagoveshchenskaya, N. F., et al.
(författare)
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Heater-induced phenomena in a coupled ionosphere-magnetosphere system
- 2006
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Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 38:11, s. 2495-2502
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results from HF pumping experiments in the nightside auroral E and F region are reported. The experiments were carried out by the use of the EISCAT HF heating facility located near Tromso, Norway, allowing HF pumping the ionosphere in a near magnetic field-aligned direction. We present experimental results from multi-instrument observations related to heater-induced phenomena in a coupled ionosphere-magnetosphere system. The following results have been observed on different occasions: a reverberation effect in scattered signals observed simultaneously on two diagnostic paths which is an indication of Alfven wave generation. This phenomenon was seen under specific disturbed background geophysical conditions, namely, a high electron density in the F region up to 8 MHz produced by soft electron precipitation from the magnetosphere along with low electron density in lower ionosphere; increased ionospheric electric fields; ion outflows from the ionosphere. On another occasion a magnetospheric response to heater turning on and off was found from magnetic pulsation observations over a frequency range up to 5 Hz (the upper frequency limit of the sensitive magnetometer at Kilpisjarvi, located near Tromso). The response manifests itself about 1 min after the heater is turned on and off. Other results have shown the modification of a natural auroral arc and local spiral-like formation. It is thought that a local heater-driven current system is formed. An interesting feature is the generation of the heater-induced ion outflows from the ionosphere. They are observed in night hours under both quiet and disturbed magnetic conditions.
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| 2. |
- Blagoveshchenskaya, N.F., Kornienko, V.A., Rietveld, M.T., Thidé, B., Brekke, A., Moskvin, I.V., Nodrachev, S.
(författare)
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Stimulated emissions around second harmonic of Tromsø heater frequency observed by long-distance diagnostic HF tools
- 1998
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Ingår i: Geophysical Research Letters. ; 25, s. 863-876
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Bottillo, Irene, et al.
(författare)
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Germline and somatic NF1 mutations in sporadic and NF1-associated malignant peripheral nerve sheath tumours
- 2009
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 217:5, s. 693-701
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Tidskriftsartikel (refereegranskat)abstract
- Malignant peripheral nerve sheath tumours (MPNSTs) are a malignancy occurring with increased frequency in patients with neurofibromatosis type 1 (NF1). In contrast to the well-known spectrum of germline NF1 mutations, the information on somatic mutations in MPNSTs is limited. In this study, we screened NF1, KRAS, and BRAF in 47 MPNSTs from patients with (n = 25) and without (n = 22) NF1. In addition, DNA from peripheral blood and cutaneous neurofibroma biopsies from, respectively, 14/25 and 7/25 of the NF1 patients were analysed. Germline NF1 mutations were detected in ten NF1 patients, including three frameshift, three nonsense, one missense, one splicing alteration, and two large deletions. Somatic NF1 mutations were found in 10/25 (40%) NF1-associated MPNSTs, in 3/7 (43%) neurofibromas, and in 9/22 (41%) sporadic MPNSTs. Large genomic copy number changes accounted for 6/10 and 7/13 somatic mutations in NF1-associated and sporadic MPNSTs, respectively. Two NF1-associated and 13 sporadic MPNSTs did not show any NF1 mutation. A major role of the KRAS and BRAF genes was ruled out. The spectrum of germline NF1 mutations in neurofibromatosis patients with MPNST is different from the spectrum of somatic mutations seen in MPNSTs. However, the somatic events share common characteristics with the NF1-related and the sporadic tumours. Copyright (C) 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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| 4. |
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| 5. |
- Frank, Brandon, et al.
(författare)
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Plasma p-tau181 shows stronger network association to Alzheimer's disease dementia than neurofilament light and total tau.
- 2022
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 18:8, s. 1523-1536
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Tidskriftsartikel (refereegranskat)abstract
- We examined the ability of plasma hyperphosphorylated tau (p-tau)181 to detect cognitive impairment due to Alzheimer's disease (AD) independently and in combination with plasma total tau (t-tau) and neurofilament light (NfL).Plasma samples were analyzed using the Simoa platform for 235 participants with normal cognition (NC), 181 with mild cognitive impairment due to AD (MCI), and 153 with AD dementia. Statistical approaches included multinomial regression and Gaussian graphical models (GGMs) to assess a network of plasma biomarkers, neuropsychological tests, and demographic variables.Plasma p-tau181 discriminated AD dementia from NC, but not MCI, and correlated with dementia severity and worse neuropsychological test performance. Plasma NfL similarly discriminated diagnostic groups. Unlike plasma NfL or t-tau, p-tau181 had a direct association with cognitive diagnosis in a bootstrapped GGM.These results support plasma p-tau181 for the detection of AD dementia and the use of blood-based biomarkers for optimal disease detection.
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| 6. |
- Bebbington, Emily, et al.
(författare)
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Exploring the similarities and differences of burn registers globally: Results from a data dictionary comparison study
- 2024
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Ingår i: Burns. - : ELSEVIER SCI LTD. - 0305-4179 .- 1879-1409. ; 50:4, s. 850-865
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Pooling and comparing data from the existing global network of burn registers represents a powerful, yet untapped, opportunity to improve burn prevention and care. There have been no studies investigating whether registers are sufficiently similar to allow data comparisons. It is also not known what differences exist that could bias analyses. Understanding this information is essential prior to any future data sharing. The aim of this project was to compare the variables collected in countrywide and intercountry burn registers to understand their similarities and differences. Methods: Register custodians were invited to participate and share their data dictionaries. Inclusion and exclusion criteria were compared to understand each register population. Descriptive statistics were calculated for the number of unique variables. Variables were classified into themes. Definition, method, timing of measurement, and response options were compared for a sample of register concepts. Results: 13 burn registries participated in the study. Inclusion criteria varied between registers. Median number of variables per register was 94 (range 28 - 890), of which 24% (range 4.8 - 100%) were required to be collected. Six themes (patient information, admission details, injury, inpatient, outpatient, other) and 41 subthemes were identified. Register concepts of age and timing of injury show similarities in data collection. Intent, mechanism, inhalational injury, infection, and patient death show greater variation in measurement. Conclusions: We found some commonalities between registers and some differences. Commonalities would assist in any future efforts to pool and compare data between registers. Differences between registers could introduce selection and measurement bias, which needs to be addressed in any strategy aiming to facilitate burn register data sharing. We recommend the development of common data elements used in an international minimum data set for burn injuries, including standard definitions and methods of measurement, as the next step in achieving burn register data sharing. (c) 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 7. |
- Birkeland, A., et al.
(författare)
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The ultrasound visualization pipeline
- 2014
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Ingår i: Mathematics and Visualization. - London : springer berlin. - 1612-3786. ; 37, s. 283-303
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Tidskriftsartikel (refereegranskat)abstract
- Radiology is one of themain tools inmodernmedicine.Anumerous set of deceases, ailments and treatments utilize accurate images of the patient. Ultrasound is one of the most frequently used imaging modality in medicine. The high spatial resolution, its interactive nature and non-invasivenessmakes it the first choice inmany examinations. Image interpretation is one of ultrasound’s main challenges. Much training is required to obtain a confident skill level in ultrasound-based diagnostics. State-of-the-art graphics techniques is needed to providemeaningful visualizations of ultrasound in real-time. In this paper we present the process-pipeline for ultrasound visualization, including an overview of the tasks performed in the specific steps. To provide an insight into the trends of ultrasound visualization research, we have selected a set of significant publications and divided them into a technique-based taxonomy covering the topics pre-processing, segmentation, registration, rendering and augmented reality. For the different technique types we discuss the difference between ultrasound-based techniques and techniques for other modalities.
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| 8. |
- Brekke, Hilde Kristin, 1972, et al.
(författare)
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Lifestyle changes can be achieved through counseling and follow-up in first-degree relatives of patients with type 2 diabetes.
- 2003
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Ingår i: Journal of the American Dietetic Association. - 0002-8223. ; 103:7, s. 835-43
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To describe two lifestyle prevention strategies tested in first-degree relatives of patients with type 2 diabetes and to present the short-term effects of these strategies on nutrient intake, physical activity pattern, and body weight. DESIGN: In this 16-week controlled intervention trial, subjects were assigned to one of three treatment conditions: diet group (D) (n=25), diet and exercise group (DE) (n=30), or control group (C) (n=22). Subjects/setting Non-diabetic relatives of individuals with diabetes were recruited (n=77; men and women; age 25 to 55 years). INTERVENTION: Intervention groups received group counseling on two occasions and follow-up through unannounced telephone interviews every 10 days. Counseling regarding diet and physical activity was based on the Nordic Nutrition Recommendations. In addition, increased intake of fatty fish and low glycemic index foods were recommended. Main outcome measures Changes in diet (assessed by food frequency questionnaires), leisure time physical activity (assessed through interviews), fatty acid composition of erythrocyte membrane, and body weight. Statistical analysis One-way analysis of variance and Mann-Whitney U test were used to compare changes among groups. RESULTS: Compared with the control group, both intervention groups decreased intake of saturated fatty acids (percent of energy), increased intake of dietary fiber, and reduced average glycemic index of the diet. The ratio of n-6:n-3 fatty acids of the erythrocyte membranes decreased, confirming increased intake of fatty fish. Body weight decreased 1.7 kg (2.1%, P=.030) in group DE, and physical activity increased in the least-active subjects (+70 min/week, P<.01 within group). Applications/Conclusions Healthy individuals with heredity for type 2 diabetes can achieve desired changes in lifestyle factors associated with increased risk for the disease.
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| 9. |
- Brekke, Helge R, et al.
(författare)
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Genomic Changes in Chromosomes 10, 16, and X in Malignant Peripheral Nerve Sheath Tumors Identify a High-Risk Patient Group.
- 2010
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Ingår i: Journal of Clinical Oncology. - 1527-7755. ; 28, s. 1573-1582
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to identify genetic aberrations contributing to clinical aggressiveness of malignant peripheral nerve sheath tumors (MPNSTs). PATIENTS AND METHODS: Samples from 48 MPNSTs and 10 neurofibromas were collected from 51 patients with (n = 31) or without (n = 20) neurofibromatosis type 1 (NF1). Genome-wide DNA copy number changes were assessed by chromosomal and array-based comparative genomic hybridization (CGH) and examined for prognostic significance. For a subset of 20 samples, RNA microarray data were integrated with the genome data to identify potential target genes. RESULTS: Forty-four (92%) MPNSTs displayed DNA copy number changes (median, 18 changes per tumor; range, 2 to 35 changes). Known frequent chromosomal gains at chromosome arms 8q (69%), 17q (67%), and 7p (52%) and losses from 9p (50%), 11q (48%), and 17p (44%) were confirmed. Additionally, gains at 16p or losses from 10q or Xq identified a high-risk group with only 11% 10-year disease-specific survival (P = .00005). Multivariate analyses including NF1 status, tumor location, size, grade, sex, complete remission, and initial metastatic status showed that the genomic high-risk group was the most significant predictor of poor survival. Several genes whose expression was affected by the DNA copy number aberrations were identified. CONCLUSION: The presence of specific genetic aberrations was strongly associated with poor survival independent of known clinical risk factors. Conversely, within the total patient cohort with 34% 10-year disease-specific survival, a low-risk group was identified: without changes at chromosomes 10q, 16p, or Xq in their MPNSTs, the patients had 74% 10-year survival.
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| 10. |
- Brekke, Helge R., et al.
(författare)
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Identification of p53 as a strong predictor of survival for patients with malignant peripheral nerve sheath tumors
- 2009
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Ingår i: Neuro-Oncology. - : Oxford University Press (OUP). - 1523-5866 .- 1522-8517. ; 11:5, s. 514-528
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to identify new prognostic biomarkers with clinical impact in malignant peripheral nerve sheath tumor (MPNST), a highly aggressive malignancy for which no consensus therapy exists besides surgery. We have used tissue microarrays (TMAs) to assess in situ expression of 14 cell-cycle-regulating proteins in 64 well-characterized MPNST patients: 36 sporadic and 28 with neurofibromatosis type 1 (NF1). We developed a new software application for evaluation and logistics of the TMA images and performed a literature survey of cell cycle proteins in MPNST. For NF1-associated patients, there was a clear association between nuclear expression of p53 and poor survival (p = 0.004). Among the other proteins analyzed, we also found significant associations between survival and clinical variables, but none were as strong as that for p53. For the total series of MPNSTs, p53 was shown to be an independent predictor of survival, and patients without remission, with tumor size larger than 8 cm, and with positive p53 expression had a 60 times greater risk of dying within the first 5 years compared with the remaining patients (p = 0.000002). This is the most comprehensive study of in situ protein expression in MPNST so far, and expressed p53 was found to be a strong surrogate marker for outcome. Patients in complete remission with a primary p53-positive MPNST diagnosis may be considered in a high-risk subgroup and candidates for adjuvant treatment. Neuro-Oncology 11, 514-528, 2009 (Posted to Neuro-Oncology [serial online], Doc. D08-00271, January 30, 2009.)
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