| 1. |
- Coustenis, A., et al.
(author)
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TandEM : Titan and Enceladus mission
- 2009
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In: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 893-946
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Journal article (peer-reviewed)abstract
- TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (MontgolfiSre) and possibly several landing probes to be delivered through the atmosphere.
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| 2. |
- Thalén, B. E., et al.
(author)
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Release of corticotropin after administration of corticotropin-releasing hormone in depressed patients in relation to the dexamethasone suppression test
- 1993
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In: Acta Psychiatrica Scandinavica. - : Wiley. - 0001-690X .- 1600-0447. ; 87:2, s. 133-140
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Journal article (peer-reviewed)abstract
- The possible hypersecretion involvement of corticotropin-releasing hormone (CRH) in the pathophysiology of hypothalamic-pituitary-adrenocortical axis disturbances in patients with major depressive episode and with an abnormal dexamethasone suppression test (DST) was investigated. The corticotropin (ACTH) and cortisol response to the injection of 45 micrograms of synthetic human CRH at 1630 were analyzed in 24 inpatients with normal (suppressors) or abnormal (nonsuppressors) DST. The outcome of the DST was analyzed using 3 cut-off points for the cortisol levels. The clinical assessments included two rating scales. The results showed that nonsuppressors had a significantly lower ACTH response to CRH stimulation than suppressors at all cut-off points (calculated as net area under the curve and as the difference between the peak and the baseline level) despite no significant differences in the severity of depression.
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| 3. |
- Almkvist, O, et al.
(author)
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Mild cognitive impairment -- An early stage of Alzheimer´s disease?
- 1998
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In: Journal of Neural Transmission. ; 53, s. 21-29
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Journal article (peer-reviewed)abstract
- The hypothesis that mild cognitive impairment (MCI) represents an early stage of Alzheimer´s disease (AD) was investigated by reviewing recent research from three sources: asymptomatic and symptomatic individuals carrying mutations that cause AD; hospital
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| 4. |
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| 5. |
- Eyjolfsdottir, H., et al.
(author)
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Targeted delivery of nerve growth factor to the cholinergic basal forebrain of Alzheimer's disease patients: application of a second-generation encapsulated cell biodelivery device
- 2016
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In: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 8
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Journal article (peer-reviewed)abstract
- Background: Targeted delivery of nerve growth factor (NGF) has emerged as a potential therapy for Alzheimer's disease (AD) due to its regenerative effects on basal forebrain cholinergic neurons. This hypothesis has been tested in patients with AD using encapsulated cell biodelivery of NGF (NGF-ECB) in a first-in-human study. We report our results from a third-dose cohort of patients receiving second-generation NGF-ECB implants with improved NGF secretion. Methods: Four patients with mild to moderate AD were recruited to participate in an open-label, phase Ib dose escalation study with a 6-month duration. Each patient underwent stereotactic implant surgery with four NGF-ECB implants targeted at the cholinergic basal forebrain. The NGF secretion of the second-generation implants was improved by using the Sleeping Beauty transposon gene expression technology and an improved three-dimensional internal scaffolding, resulting in production of about 10 ng NGF/device/day. Results: All patients underwent successful implant procedures without complications, and all patients completed the study, including implant removal after 6 months. Upon removal, 13 of 16 implants released NGF, 8 implants released NGF at the same rate or higher than before the implant procedure, and 3 implants failed to release detectable amounts of NGF. Of 16 adverse events, none was NGF-, or implant-related. Changes from baseline values of cholinergic markers in cerebrospinal fluid (CSF) correlated with cortical nicotinic receptor expression and Mini Mental State Examination score. Levels of neurofilament light chain (NFL) protein increased in CSF after NGF-ECB implant, while glial fibrillary acidic protein (GFAP) remained stable. Conclusions: The data derived from this patient cohort demonstrate the safety and tolerability of sustained NGF release by a second-generation NGF-ECB implant to the basal forebrain, with uneventful surgical implant and removal of NGF-ECB implants in a new dosing cohort of four patients with AD.
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| 6. |
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| 7. |
- Liberg, B., et al.
(author)
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The neural correlates of self-paced finger tapping in bipolar depression with motor retardation
- 2013
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In: Acta Neuropsychiatrica. - : Cambridge University Press (CUP). - 0924-2708 .- 1601-5215. ; 25:1, s. 43-51
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Journal article (peer-reviewed)abstract
- Objective: Motor retardation is a characteristic feature of bipolar depression, and is also a core feature of Parkinson's disease. Within the framework of the functional deafferentiation theory in Parkinson's disease, we hypothesised that motor retardation in bipolar depression is mediated by disrupted subcortical activation, leading to decreased activation of cortical motor areas during finger tapping. Methods: We used functional magnetic resonance imaging to investigate neural activity during self-paced finger tapping to elucidate whether brain regions that mediate preparation, control and execution of movement are activated differently in subjects with bipolar depression (n = 9) compared to healthy controls (n = 12). Results: An uncorrected whole-brain analysis revealed significant group differences in dorsolateral and ventromedial prefrontal cortex. Corrected analyses showed non-significant differences in patients compared to controls: decreased and less widespread activation of the left putamen and left pallidum; increased activity in the left thalamus and supplementary motor area; decreased activation in the left lateral pre- and primary motor cortices; absence of activation in the pre-supplementary motor area; activation of the bilateral rostral cingulate motor area. Conclusion: Both movement preparation and execution may be affected in motor retardation, and the activity in the whole left-side motor circuit is altered during self-initiated motor performance in bipolar depression.
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| 8. |
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| 9. |
- Visser, P. J., et al.
(author)
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Development of screening guidelines and clinical criteria for predementia Alzheimer's disease
- 2008
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In: Neuroepidemiology. - : S. Karger AG. - 1423-0208 .- 0251-5350. ; 30:4, s. 254-265
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Journal article (peer-reviewed)abstract
- Background: There is an urgent need to identify subjects with Alzheimer's disease (AD) in the predementia phase, but validated diagnostic approaches are currently lacking. In this paper, we present the background, design and methods of a study, which aims to develop clinical criteria for predementia AD. We also present baseline characteristics of the subjects included. The study was part of the multicentre DESCRIPA project, which is being conducted within the network of the European Alzheimer's Disease Consortium. Methods: Clinical criteria will be based on a prospective cohort study of non-demented subjects older than 55 years and referred to a memory clinic. At baseline, a number of markers and risk factors for AD were collected, including demographic variables, measures of performance in activities of daily living, cognitive, neuroimaging and genetic markers, and serum and cerebrospinal fluid markers. Subjects will be reassessed annually for 2 - 3 years, and we will evaluate which combination of variables best predicts AD-type dementia at follow-up. Results: Between 2003 and 2005, 881 subjects were included from 20 memory clinics. Subjects were on average 70.3 years old, and had 10.4 years of education. The average score on the Mini-Mental State Examination was 27.4.
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| 10. |
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| 11. |
- Besga, A., et al.
(author)
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Differences in brain cholesterol metabolism and insulin in two subgroups of patients with different CSF biomarkers but similar white matter lesions suggest different pathogenic mechanisms
- 2012
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In: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 510:2, s. 121-126
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Journal article (peer-reviewed)abstract
- Investigate possible associations of white matter hyperintensities (WMHs) with the metabolism of cholesterol and insulin in two subgroups of patients with memory complaints and different CSF A beta 42 and CSF tau levels. 59 patients from the memory clinic at Karolinska Hospital were included. Degree of WMHs was rated using the ARWMC scale and the following biomarkers were measured in CSF and plasma: insulin, cholesterol, lanosterol, lathosterol, and oxidized cholesterol metabolites. The WMHs in CSF control-like group correlated with increased brain cholesterol synthesis and reduced efflux of oxysterols and insulin in CSF. In the CSF AD-like group, the WMHs correlated with increased peripheral cholesterol metabolism. Despite having similar appearance on FLAIR images, the pathogenic mechanisms of WMHS are likely to be different in the two groups investigated.
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| 12. |
- Boström, R., Eriksson, A.I., Åhlén, L., Blomberg, L., Gustafsson, G., Holback, B., Holmgren, G., Holtet, J., Jansson, S.E., Lindqvist, P.A., Lybekk, B., Mälkki, A., Riihelä, P. and Wahlund, J.E.
(author)
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The Rosetta Dual Langmuir Probe Instrument for Measurements of Plasma Density, Temperature and Flow Velocity.
- 2001
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In: ESA SP-1165.
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Conference paper (other academic/artistic)
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| 13. |
- Dyrby, Tim B, et al.
(author)
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Segmentation of age-related white matter changes in a clinical multi-center study.
- 2008
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In: NeuroImage. - : Elsevier BV. - 1053-8119. ; 41:2, s. 335-45
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Journal article (peer-reviewed)abstract
- Age-related white matter changes (WMC) are thought to be a marker of vascular pathology, and have been associated with motor and cognitive deficits. In the present study, an optimized artificial neural network was used as an automatic segmentation method to produce probabilistic maps of WMC in a clinical multi-center study. The neural network uses information from T1- and T2-weighted and fluid attenuation inversion recovery (FLAIR) magnetic resonance (MR) scans, neighboring voxels and spatial location. Generalizability of the neural network was optimized by including the Optimal Brain Damage (OBD) pruning method in the training stage. Six optimized neural networks were produced to investigate the impact of different input information on WMC segmentation. The automatic segmentation method was applied to MR scans of 362 non-demented elderly subjects from 11 centers in the European multi-center study Leukoaraiosis And Disability (LADIS). Semi-manually delineated WMC were used for validating the segmentation produced by the neural networks. The neural network segmentation demonstrated high consistency between subjects and centers, making it a promising technique for large studies. For WMC volumes less than 10 ml, an increasing discrepancy between semi-manual and neural network segmentation was observed using the similarity index (SI) measure. The use of all three image modalities significantly improved cross-center generalizability compared to neural networks using the FLAIR image only. Expert knowledge not available to the neural networks was a minor source of discrepancy, while variation in MR scan quality constituted the largest source of error.
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| 14. |
- Enache, D, et al.
(author)
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Medial temporal lobe atrophy and depressive symptoms in elderly patients with and without Alzheimer disease
- 2015
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In: Journal of geriatric psychiatry and neurology. - : SAGE Publications. - 0891-9887 .- 1552-5708. ; 28:1, s. 40-48
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Journal article (peer-reviewed)abstract
- To determine whether depressive symptoms are associated with medial temporal lobe atrophy in older people with and without Alzheimer disease (AD).Method:A total of 368 memory clinic patients with AD, mild cognitive impairment, and subjective cognitive impairment (SCI) were included. Depressive symptoms were defined as a score of 8 or higher on Cornell Scale for Depression in Dementia or use of antidepressant medications. Magnetic resonance imaging and computer tomography scans were rated for medial temporal lobe atrophy (MTA), using the Scheltens scale. For a subsample (n = 57 patients), hippocampal volume was manually traced.Results:Based on visual assessment, AD patients with depressive symptoms had less atrophy of the right medial temporal lobe (odds ratio [OR] for having MTA: 0.39; 95% confidence interval [CI] 0.16-0.99) and decreased scores on Scheltens scale for the left medial temporal lobe (OR: 0.43, 95% CI 0.19-0.96) in comparison to AD patients without depressive symptoms. In the subgroup where manual tracing was used to measure hippocampal volume, people with SCI experiencing depressive symptoms had smaller right (mean difference: 0.28 cm3; P = .005) and left (mean difference 0.32 cm3; P = .002) hippocampal volumes compared to people with SCI who did not have depressive symptoms.Conclusion:Hippocampal atrophy was more pronounced among patients having SCI with depressive symptoms, while the medial temporal lobe was less atrophic in patients having AD with depressive symptoms than those without depressive symptoms. These findings suggest that different mechanisms underlie depression in older people with and without AD and may explain some of the inconsistent observations in previous studies.
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| 15. |
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| 16. |
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| 17. |
- Gustafsson, Georg, et al.
(author)
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First results of electric field and density observations by Cluster EFW based on initial months of operation
- 2001
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In: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 19:12-okt, s. 1219-1240
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Journal article (peer-reviewed)abstract
- Highlights are presented from studies of the electric field data from various regions along the CLUSTER orbit. They all point towards a very high coherence for phenomena recorded on four spacecraft that are separated by a few hundred kilometers for structures over the whole range of apparent frequencies from I mHz to 9 kHz. This presents completely new opportunities to study spatial-temporal plasma phenomena from the magnetosphere out to the solar wind. A new probe environment was constructed for the CLUSTER electric field experiment that now produces data of unprecedented quality. Determination of plasma flow in the solar wind is an example of the capability of the instrument.
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| 18. |
- Herique, A., et al.
(author)
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Direct observations of asteroid interior and regolith structure : Science measurement requirements
- 2018
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In: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 62:8, s. 2141-2162
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Journal article (peer-reviewed)abstract
- Our knowledge of the internal structure of asteroids is, so far, indirect - relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling of formation and evolution. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape asteroid internal structures? Is the composition and size distribution observed on the surface representative of the bulk? These questions are crucial to understand small bodies' history from accretion in the early Solar System to the present, and direct measurements are needed to answer these questions for the benefit of science as well as for planetary defense or exploration. Radar is one of the main instruments capable of sounding asteroids to characterize internal structure from sub-meter to global scale. In this paper, we review the science case for direct observation of the deep internal structure and regolith of a rocky asteroid of kilometer size or smaller. We establish the requirements and model dielectric properties of asteroids to outline a possible instrument suite, and highlight the capabilities of radar instrumentation to achieve these observations. We then review the expected science return including secondary objectives contributing to the determination of the gravitational field, the shape model, and the dynamical state. This work is largely inherited from MarcoPolo-R and AIDA/AIM studies.
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| 19. |
- Ismail, MA, et al.
(author)
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27-Hydroxycholesterol impairs neuronal glucose uptake through an IRAP/GLUT4 system dysregulation
- 2017
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In: The Journal of experimental medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 214:3, s. 699-717
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Journal article (peer-reviewed)abstract
- Hypercholesterolemia is associated with cognitively deteriorated states. Here, we show that excess 27-hydroxycholesterol (27-OH), a cholesterol metabolite passing from the circulation into the brain, reduced in vivo brain glucose uptake, GLUT4 expression, and spatial memory. Furthermore, patients exhibiting higher 27-OH levels had reduced 18F-fluorodeoxyglucose uptake. This interplay between 27-OH and glucose uptake revealed the engagement of the insulin-regulated aminopeptidase (IRAP). 27-OH increased the levels and activity of IRAP, countered the IRAP antagonist angiotensin IV (AngIV)–mediated glucose uptake, and enhanced the levels of the AngIV-degrading enzyme aminopeptidase N (AP-N). These effects were mediated by liver X receptors. Our results reveal a molecular link between cholesterol, brain glucose, and the brain renin-angiotensin system, all of which are affected in some neurodegenerative diseases. Thus, reducing 27-OH levels or inhibiting AP-N maybe a useful strategy in the prevention of the altered glucose metabolism and memory decline in these disorders.
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| 20. |
- Jonhagen, ME, et al.
(author)
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Intracerebroventricular infusion of nerve growth factor in three patients with Alzheimer's disease
- 1998
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In: Dementia and geriatric cognitive disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 9:5, s. 246-257
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Journal article (peer-reviewed)abstract
- Nerve growth factor (NGF) is important for the survival and maintenance of central cholinergic neurons, a signalling system impaired in Alzheimer’s disease. We have treated 3 patients with Alzheimer’s disease with a total of 6.6 mg NGF administered continuously into the lateral cerebral ventricle for 3 months in the first 2 patients and a total of 0.55 mg for 3 shorter periods in the third patient. The patients were extensively evaluated with clinical, neuropsychological, neurophysiological and neuroradiological techniques. Three months after the NGF treatment ended, a significant increase in nicotine binding was found in several brain areas in the first 2 patients and in the hippocampus in the third patient as studied by positron emission tomography. A clear cognitive amelioration could not be demonstrated, although a few neuropsychology tests showed slight improvements. The amount of slow-wave cortical activity as studied by electroencephalography was reduced in the first 2 patients. Two negative side effects occurred with NGF treatment: first, a dull, constant back pain was observed in all 3 patients, which in 1 patient was aggravated by axial loading resulting in sharp, shooting pain of short duration. When stopping the NGF infusion, the pain disappeared within a couple of days. Reducing the dose of NGF lessened the pain. Secondly, a marked weight reduction during the infusion with a clear weight gain after ending the infusion was seen in the first 2 patients. We conclude from this limited trial that, while long-term intracerebroventricular NGF administration may cause certain potentially beneficial effects, the intraventricular route of administration is also associated with negative side effects that appear to outweigh the positive effects of the present protocol. Alternative routes of administration, and/or lower doses of NGF, perhaps combined with low doses of other neurotrophic factors, may shift this balance in favor of positive effects.
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| 21. |
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| 22. |
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| 23. |
- Macfarlane, M. D., et al.
(author)
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Shape abnormalities of the caudate nucleus correlate with poorer gait and balance: Results from a subset of the ladis study
- 2015
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In: The American journal of geriatric psychiatry. - : Elsevier BV. - 1064-7481. ; 23:1, s. 59-
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Journal article (peer-reviewed)abstract
- Objective Functional deficits seen in several neurodegenerative disorders have been linked with dysfunction in frontostriatal circuits and with associated shape alterations in striatal structures. The severity of visible white matter hyperintensities (WMHs) on magnetic resonance imaging has been found to correlate with poorer performance on measures of gait and balance. This study aimed to determine whether striatal volume and shape changes were correlated with gait dysfunction. Methods Magnetic resonance imaging scans and clinical gait/balance data (scores from the Short Physical Performance Battery [SPPB]) were sourced from 66 subjects in the previously published LADIS trial, performed in nondisabled individuals older than age 65 years with WMHs at study entry. Data were obtained at study entry and at 3-year follow-up. Caudate nuclei and putamina were manually traced using a previously published method and volumes calculated. The relationships between volume and physical performance on the SPPB were investigated with shape analysis using the spherical harmonic shape description toolkit. Results There was no correlation between the severity of WMHs and striatal volumes. Caudate nuclei volume correlated with performance on the SPPB at baseline but not at follow-up, with subsequent shape analysis showing left caudate changes occurred in areas corresponding to inputs of the dorsolateral prefrontal, premotor, and motor cortex. There was no correlation between putamen volumes and performance on the SPPB. Conclusion Disruption in frontostriatal circuits may play a role in mediating poorer physical performance in individuals with WMHs. Striatal volume and shape changes may be suitable biomarkers for functional changes in this population. © 2015 American Association for Geriatric Psychiatry.
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| 24. |
- Milillo, A., et al.
(author)
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Investigating Mercury's Environment with the Two-Spacecraft BepiColombo Mission
- 2020
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In: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 216:5
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Research review (peer-reviewed)abstract
- The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well as their interactions with the solar wind, radiation, and interplanetary dust. Many scientific instruments onboard the two spacecraft will be completely, or partially devoted to study the near-space environment of Mercury as well as the complex processes that govern it. Many issues remain unsolved even after the MESSENGER mission that ended in 2015. The specific orbits of the two spacecraft, MPO and Mio, and the comprehensive scientific payload allow a wider range of scientific questions to be addressed than those that could be achieved by the individual instruments acting alone, or by previous missions. These joint observations are of key importance because many phenomena in Mercury's environment are highly temporally and spatially variable. Examples of possible coordinated observations are described in this article, analysing the required geometrical conditions, pointing, resolutions and operation timing of different BepiColombo instruments sensors.
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| 25. |
- Norberg, Joakim, et al.
(author)
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Regional Differences in Effects of APOE epsilon 4 on Cognitive Impairment in Non-Demented Subjects
- 2011
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In: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 32:2, s. 135-142
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Journal article (peer-reviewed)abstract
- Background: The APOE epsilon 4 allele is a risk factor for Alzheimer's disease (AD). APOE epsilon 4 is common in non-demented subjects with cognitive impairment. In both healthy people and people with AD, its prevalence has a north-south gradient across Europe. In the present study, we investigated whether the relation between the APOE epsilon 4 allele and cognitive impairment varied across Northern, Middle and Southern Europe. We also investigated whether a north-south gradient existed in subjects with subjective cognitive impairment (SCI), amnestic mild cognitive impairment (MCI) and non-amnestic MCI. Methods: Data from 16 centers across Europe were analyzed. Results: A north-south gradient in APOE epsilon 4 prevalence existed in the total sample (62.7% for APOE epsilon 4 carriers in the northern region, 42.1% in the middle region, and 31.5% in the southern region) and in subjects with SCI and amnestic MCI separately. Only in Middle Europe was the APOE epsilon 4 allele significantly associated with poor performance on tests of delayed recall and learning, as well as with the amnestic subtype of MCI. Conclusion: The APOE epsilon 4 allele frequencies in subjects with SCI and amnestic MCI have a north-south gradient. The relation between the APOE epsilon 4 allele and cognition is region dependent.
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| 26. |
- Persoon, A. M., et al.
(author)
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A diffusive equilibrium model for the plasma density in Saturn's magnetosphere
- 2009
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In: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 114:4, s. A04211-
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Journal article (peer-reviewed)abstract
- Electron density measurements have been obtained by the Cassini Radio and Plasma Wave Science (RPWS) instrument for more than 50 passes through Saturn's inner magnetosphere from 30 June 2004 to 30 September 2007. The electron densities are derived from RPWS measurements of the upper hybrid resonance frequency and span latitudes up to 35 degrees and L values from 3.6 to 10. The electron density measurements are combined with ion anisotropy measurements from the Cassini Plasma Spectrometer (CAPS) and electron temperature measurements from the RPWS and CAPS to develop a diffusive equilibrium model for the distribution of water group ions, hydrogen ions, and electrons in the inner region of Saturn's magnetosphere. The model uses an analytical solution of the field-aligned force equation, including the ambipolar electric field, to determine the equatorial ion densities and scale heights as a function of L. Density contour plots for water group ions, hydrogen ions, and electrons are presented.
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| 27. |
- Porsch, B, et al.
(author)
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Molecular mass distribution analysis of ethyl(hydroxyethyl)cellulose by size-exclusion chromatography with dual light-scattering and refractometric detection
- 2002
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In: Journal of Chromatography A. - 0021-9673. ; 946:1-2, s. 69-81
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Journal article (peer-reviewed)abstract
- Dual low-angle light scattering and refractometric detection coupled to size-exclusion chromatography provided proof for the presence of a low amount of stable aggregates/particles in ethyl(hydroxyethyl)cellulose. Unlike the correct size-exclusion chromatographic behavior of the parent polysaccharide itself, the aggregates exhibit variable size-dependent weak retention as a function of flow-rate and of ionic strength of the aqueous mobile phase. Therefore, determination of the molecular mass of non-aggregated polymer is possible in aqueous mobile phase containing 0.1 M NaCl under conditions at which aggregates are completely adsorbed on the column packing irrespective of the flow-rate used. Flow-rate and ionic strength-dependent variations of aggregate behavior as well as model size-exclusion experiments with latex particles indicate that they partly carry a minute charge and have a compact structure. Their weak retention under the separation conditions used suggests a difference in their surface chemistry when compared with the dissolved polymer coils which exhibit a correct size-exclusion behavior. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 28. |
- Srikrishna, Meera, et al.
(author)
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CT-based volumetric measures obtained through deep learning: Association with biomarkers of neurodegeneration
- 2024
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In: Alzheimers & Dementia. - 1552-5260. ; 20:1, s. 629-640
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Journal article (peer-reviewed)abstract
- INTRODUCTIONCranial computed tomography (CT) is an affordable and widely available imaging modality that is used to assess structural abnormalities, but not to quantify neurodegeneration. Previously we developed a deep-learning-based model that produced accurate and robust cranial CT tissue classification.MATERIALS AND METHODSWe analyzed 917 CT and 744 magnetic resonance (MR) scans from the Gothenburg H70 Birth Cohort, and 204 CT and 241 MR scans from participants of the Memory Clinic Cohort, Singapore. We tested associations between six CT-based volumetric measures (CTVMs) and existing clinical diagnoses, fluid and imaging biomarkers, and measures of cognition.RESULTSCTVMs differentiated cognitively healthy individuals from dementia and prodromal dementia patients with high accuracy levels comparable to MR-based measures. CTVMs were significantly associated with measures of cognition and biochemical markers of neurodegeneration.DISCUSSIONThese findings suggest the potential future use of CT-based volumetric measures as an informative first-line examination tool for neurodegenerative disease diagnostics after further validation.HIGHLIGHTSComputed tomography (CT)-based volumetric measures can distinguish between patients with neurodegenerative disease and healthy controls, as well as between patients with prodromal dementia and controls.CT-based volumetric measures associate well with relevant cognitive, biochemical, and neuroimaging markers of neurodegenerative diseases.Model performance, in terms of brain tissue classification, was consistent across two cohorts of diverse nature.Intermodality agreement between our automated CT-based and established magnetic resonance (MR)-based image segmentations was stronger than the agreement between visual CT and MR imaging assessment.
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| 29. |
- Vos, S. J. B., et al.
(author)
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Prediction of Alzheimer disease in subjects with amnestic and nonamnestic MCI
- 2013
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In: Neurology. - 0028-3878 .- 1526-632X. ; 80:12, s. 1124-1132
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Journal article (peer-reviewed)abstract
- Objective: To compare the predictive accuracy of beta-amyloid (A beta)1-42 and total tau in CSF, Methods: We selected 399 subjects with aMCI and 226 subjects with naMCI from a multicenter Results: At least 1 follow-up was available for 538 subjects (86%). One hundred thirty-two subjects with Conclusions: AD biomarkers are useful to predict AD-type dementia in subjects with aMCI and naMCI.
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| 30. |
- Wahlund, B, et al.
(author)
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Seizure (Ictal)--EEG characteristics in subgroups of depressive disorder in patients receiving electroconvulsive therapy (ECT)--a preliminary study and multivariate approach
- 2009
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In: Computational intelligence and neuroscience. - : Hindawi Limited. - 1687-5273 .- 1687-5265. ; , s. 965209-
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Journal article (peer-reviewed)abstract
- Objectives. Examine frequency distributions of ictal EEG after ECT stimulation in diagnostic subgroups of depression.Methods. EEG registration was consecutively monitored in 33 patients after ECT stimulation. Patients were diagnosed according to DSM IV and subdivided into: (1) major depressive disorder with psychotic features(n=7), (2) unipolar depression(n=20), and (3) bipolar depression(n=6).Results. Results indicate that the diagnostically subgroups differ in their ictal EEG frequency spectrumml: (1) psychotic depression has a high occurrence of delta and theta waves, (2) unipolar depression has high occurrence of delta, theta and gamma waves, and (3) bipolar depression has a high occurrence of gamma waves. A linear discriminant function separated the three clinical groups with an accuracy of 94%.Conclusion. Psychotic depressed patients differ from bipolar depression in their frequency based on probability distribution of ictal EEG. Psychotic depressed patients show more prominent slowing of EEG than nonpsychotic depressed patients. Thus the EEG results may be supportive in classifying subgroups of depression already at the start of the ECT treatment.
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| 36. |
- Andersson, L, et al.
(author)
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Electron signatures and Alfven waves
- 2002
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In: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 107:A9
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Journal article (peer-reviewed)abstract
- [1] We identify two distinct electron populations associated with Alfven waves in the Freja data set using the high time resolution state of the art electron detector. One of the populations, detected together with an Alfven wave, is field-aligned and can be seen as trapped within the wave. The other electron population is detected before the wave and consists of electrons which have left the wave at a point with a velocity higher than the local Alfven speed. In the paper, the electrons leaving wave are modeled for different density profiles and are compared with the observed data. Depending on the density profile, the model can produce the same energy-time and pitch angle-time dispersion that is observed in the Freja data. The conclusion of the paper is that the Alfven wave can explain the observed particle signatures. It is shown that the Alfven wave acceleration can create electron signatures similar to inverted-V structures. The density distribution along a flux tube has an important role in the type of particle signatures that can be detected at low altitudes.
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| 37. |
- Andersson, L., Wahlund, J.E., Clemmons, J., Gustavsson, B. and Eliasson, L.
(author)
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Electromagnetic waves and bursty electron acceleration: implications from Freja.
- 2001
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In: Annales Geophysicae. ; 20:2, s. 139-150
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Journal article (peer-reviewed)abstract
- Dispersive Alfven wave activity is identified in four dayside auroral oval events measured by the Freja satellite. The events are characterized by ion injection, bursty electron precipitation below about 1 keV, transverse ion heating and broadband extreme
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| 38. |
- Andersson, M, et al.
(author)
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Accuracy in multiangle light scattering measurements for molar mass and radius estimations. Model calculations and experiments.
- 2003
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 75:16, s. 4279-4291
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Journal article (peer-reviewed)abstract
- Multiangle light scattering (MALS) is a well-established technique used to determine the size of macromolecules and particles. In this study, different extrapolation procedures used in MALS were investigated with regard to accuracy and robustness in the obtained molar mass and rms radius. Three different mathematical transformations of the light scattering function referred to as the Debye, Zimm, and Berry methods for constructing the Debye plot were investigated for two idealized polymer shapes, homogeneous spheres and random coils, with radii from 25 to 250 nm. The effect of the angular interval used for the extrapolation was investigated, as was the robustness of the different transformations toward errors in the measured light scattering intensity at low angles. For an rms radius less than 50 nm, the relative error in molar mass due to extrapolation was less than 1% independent of the method used. For larger radii, the error increased and the extrapolation procedure became more critical. For random coil polymers, the Berry method was superior in terms of accuracy and robustness. For spheres, the Debye method was superior. The Zimm method was inferior to the others. The different extrapolation methods were evaluated and compared on experimental data from a size exclusion chromatography-MALS analysis of an ultrahigh molar mass poly(ethylene oxide) (PEO). The PEO data qualitatively verified the calculations and stressed the importance of optimizing the extrapolation procedure after careful evaluation of the experimental data. A discussion of how to detect erroneous data in an experimental Debye plot is given.
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| 39. |
- Andersson, M., et al.
(author)
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Size and structure characterization of ethylhydroxyethyl cellulose by the combination of field-flow fractionation with other techniques. Investigation of ultralarge components
- 2004
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In: Biomacromolecules. - : Wiley. - 1525-7797 .- 1526-4602. ; 5:1, s. 97-105
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Journal article (peer-reviewed)abstract
- Ethylhydroxyethyl cellulose (EHEC) of three different viscosity classes (EHEC I, II, and III) was analyzed by programmed cross-flow asymmetrical flow field-flow fractionation coupled to multiangle light scattering and refractive index detectors to determine their size and molar mass distribution. Two size populations were detected in the two lower viscosity classes, EHEC I and II, one high molar mass and one ultrahigh molar mass (UHM). The two covered molar masses from 10(4) up to 10(9) g.mol(-1). The highest viscosity class EHEC III was less size-dispersed covering molar masses from 5x10(5) to 5x10(7) g.mol(-1). Filtering of the EHEC II solution removed small amounts of compact UHM material. Enzyme treatments were performed on EHEC II to further characterize it. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and anion ion-exchange chromatography coupled to pulsed amperometric detection showed that the UHM component contained EHEC.
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| 41. |
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| 44. |
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| 45. |
- Arridge, Christopher S., et al.
(author)
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Uranus Pathfinder : exploring the origins and evolution of Ice Giant planets
- 2012
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In: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 33:2-3, s. 753-791
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Journal article (peer-reviewed)abstract
- The "Ice Giants" Uranus and Neptune are a different class of planet compared to Jupiter and Saturn. Studying these objects is important for furthering our understanding of the formation and evolution of the planets, and unravelling the fundamental physical and chemical processes in the Solar System. The importance of filling these gaps in our knowledge of the Solar System is particularly acute when trying to apply our understanding to the numerous planetary systems that have been discovered around other stars. The Uranus Pathfinder (UP) mission thus represents the quintessential aspects of the objectives of the European planetary community as expressed in ESA's Cosmic Vision 2015-2025. UP was proposed to the European Space Agency's M3 call for medium-class missions in 2010 and proposed to be the first orbiter of an Ice Giant planet. As the most accessible Ice Giant within the M-class mission envelope Uranus was identified as the mission target. Although not selected for this call the UP mission concept provides a baseline framework for the exploration of Uranus with existing low-cost platforms and underlines the need to develop power sources suitable for the outer Solar System. The UP science case is based around exploring the origins, evolution, and processes at work in Ice Giant planetary systems. Three broad themes were identified: (1) Uranus as an Ice Giant, (2) An Ice Giant planetary system, and (3) An asymmetric magnetosphere. Due to the long interplanetary transfer from Earth to Uranus a significant cruise-phase science theme was also developed. The UP mission concept calls for the use of a Mars Express/Rosetta-type platform to launch on a Soyuz-Fregat in 2021 and entering into an eccentric polar orbit around Uranus in the 2036-2037 timeframe. The science payload has a strong heritage in Europe and beyond and requires no significant technology developments.
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| 46. |
- Badji, A., et al.
(author)
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Cerebrospinal Fluid Biomarkers, Brain Structural and Cognitive Performances Between Normotensive and Hypertensive Controlled, Uncontrolled and Untreated 70-Year-Old Adults
- 2022
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In: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 13
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Journal article (peer-reviewed)abstract
- Background: Hypertension is an important risk factor for Alzheimer's disease (AD). The pathophysiological mechanisms underlying the relationship between AD and hypertension are not fully understood, but they most likely involve microvascular dysfunction and cerebrovascular pathology. Although previous studies have assessed the impact of hypertension on different markers of brain integrity, no study has yet provided a comprehensive comparison of cerebrospinal fluid (CSF) biomarkers and structural brain differences between normotensive and hypertensive groups in a single and large cohort of older adults in relationship to cognitive performances.Objective: The aim of the present work was to investigate the differences in cognitive performances, CSF biomarkers and magnetic resonance imaging (MRI) of brain structure between normotensive, controlled hypertensive, uncontrolled hypertensive, and untreated hypertensive older adults from the Gothenburg H70 Birth Cohort Studies.Methods: As an indicator of vascular brain pathology, we measured white matter hyperintensities (WMHs), lacunes, cerebral microbleeds, enlarged perivascular space (epvs), and fractional anisotropy (FA). To assess markers of AD pathology/neurodegeneration, we measured hippocampal volume, temporal cortical thickness on MRI, and amyloid-beta(42), phosphorylated tau, and neurofilament light protein (NfL) in cerebrospinal fluid. Various neuropsychological tests were used to assess performances in memory, attention/processing speed, executive function, verbal fluency, and visuospatial abilities.Results: We found more white matter pathology in hypertensive compared to normotensive participants, with the highest vascular burden in uncontrolled participants (e.g., lower FA, more WMHs, and epvs). No significant difference was found in any MRI or CSF markers of AD pathology/neurodegeneration when comparing normotensive and hypertensive participants, nor among hypertensive groups. No significant difference was found in most cognitive functions between groups.Conclusion: Our results suggest that good blood pressure control may help prevent cerebrovascular pathology. In addition, hypertension may contribute to cognitive decline through its effect on cerebrovascular pathology rather than AD-related pathology. These findings suggest that hypertension is associated with MRI markers of vascular pathology in the absence of a significant decline in cognitive functions.
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