| 1. |
- Ozcelik, Ozgur, et al.
(författare)
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System Identification of a Six-Span Railway Bridge Using Ambient Vibration Measurements at Different Temperature Conditions
- 2019
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Ingår i: Journal of performance of constructed facilities. - : American Society of Civil Engineers (ASCE). - 0887-3828 .- 1943-5509. ; 33:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents modal parameter estimation work on a steel railway bridge at three different temperature conditions using ambient vibration test data. The bridge was built at the end of the 19th century using the available technology of its time. It is composed of six spans, each 30 m long, with a total length of 180 m. It is slightly curved in the horizontal plane with a radius of 300 m, and has a vertical grade of 2.5%. Modal parameters of the bridge were estimated using two different output-only system identification methods. The identified results obtained under different temperature conditions were compared in assessing the effects of temperature variation in the identification results. A comparative study in assessing method-to-method and test-to-test variability was also conducted. A three-dimensional finite-element model of the bridge was developed. In order to match the experimentally obtained modal parameters with the numerical ones, a trial-and-error–based model updating study was conducted. This way, a benchmark model of the 199+325 steel railway bridge was obtained for future capacity assessment, prediction, and sensitivity-based model updating work.
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| 2. |
- Sarp, Salih, et al.
(författare)
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An XAI approach for COVID-19 detection using transfer learning with X-ray images
- 2023
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Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 9:4
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Tidskriftsartikel (refereegranskat)abstract
- The coronavirus disease (COVID-19) has continued to cause severe challenges during this unprecedented time, affecting every part of daily life in terms of health, economics, and social development. There is an increasing demand for chest X-ray (CXR) scans, as pneumonia is the primary and vital complication of COVID-19. CXR is widely used as a screening tool for lung-related diseases due to its simple and relatively inexpensive application. However, these scans require expert radiologists to interpret the results for clinical decisions, i.e., diagnosis, treatment, and prognosis. The digitalization of various sectors, including healthcare, has accelerated during the pandemic, with the use and importance of Artificial Intelligence (AI) dramatically increasing. This paper proposes a model using an Explainable Artificial Intelligence (XAI) technique to detect and interpret COVID-19 positive CXR images. We further analyze the impact of COVID-19 positive CXR images using heatmaps. The proposed model leverages transfer learning and data augmentation techniques for faster and more adequate model training. Lung segmentation is applied to enhance the model performance further. We conducted a pre-trained network comparison with the highest classification performance (F1-Score: 98%) using the ResNet model. © 2023 The Author(s)
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| 3. |
- Alderson, Helen V, et al.
(författare)
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Longitudinal change in c-terminal fibroblast growth factor 23 and outcomes in patients with advanced chronic kidney disease
- 2021
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Ingår i: BMC Nephrology. - : BioMed Central (BMC). - 1471-2369. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Fibroblast growth factor23 (FGF23) is elevated in CKD and has been associated with outcomes such as death, cardiovascular (CV) events and progression to Renal Replacement therapy (RRT). The majority of studies have been unable to account for change in FGF23 over time and those which have demonstrate conflicting results. We performed a survival analysis looking at change in c-terminal FGF23 (cFGF23) over time to assess the relative contribution of cFGF23 to these outcomes.METHODS: We measured cFGF23 on plasma samples from 388 patients with CKD 3-5 who had serial measurements of cFGF23, with a mean of 4.2 samples per individual. We used linear regression analysis to assess the annual rate of change in cFGF23 and assessed the relationship between time-varying cFGF23 and the outcomes in a cox-regression analysis.RESULTS: Across our population, median baseline eGFR was 32.3mls/min/1.73m2, median baseline cFGF23 was 162 relative units/ml (RU/ml) (IQR 101-244 RU/mL). Over 70 months (IQR 53-97) median follow-up, 76 (19.6%) patients progressed to RRT, 86 (22.2%) died, and 52 (13.4%) suffered a major non-fatal CV event. On multivariate analysis, longitudinal change in cFGF23 was significantly associated with risk for death and progression to RRT but not non-fatal cardiovascular events.CONCLUSION: In our study, increasing cFGF23 was significantly associated with risk for death and RRT.
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| 4. |
- Arridge, Christopher S., et al.
(författare)
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Uranus Pathfinder : exploring the origins and evolution of Ice Giant planets
- 2012
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 33:2-3, s. 753-791
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Arslan, Engin, et al.
(författare)
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SiC Substrate Effects on Electron Transport in the Epitaxial Graphene Layer
- 2014
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Ingår i: ELECTRONIC MATERIALS LETTERS. - : Springer Science and Business Media. - 1738-8090 .- 2093-6788. ; 10:2, s. 387-391
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Tidskriftsartikel (refereegranskat)abstract
- Hall effect measurements on epitaxial graphene (EG) on SiC substrate have been carried out as a function of temperature. The mobility and concentration of electrons within the two-dimensional electron gas (2DEG) at the EG layers and within the underlying SiC substrate are readily separated and characterized by the simple parallel conduction extraction method (SPCEM). Two electron carriers are identified in the EG/SiC sample: one high-mobility carrier (3493 cm(2)/Vs at 300 K) and one low-mobility carrier (1115 cm(2)/Vs at 300 K). The high mobility carrier can be assigned to the graphene layers. The second carrier has been assigned to the SiC substrate.
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| 6. |
- Asa, Sylvia L., et al.
(författare)
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Pituitary neuroendocrine tumors : a model for neuroendocrine tumor classification
- 2021
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Ingår i: Modern Pathology. - : Springer Nature. - 0893-3952 .- 1530-0285. ; 34:9, s. 1634-1650
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Forskningsöversikt (refereegranskat)abstract
- The classification of adenohypophysial neoplasms as "pituitary neuroendocrine tumors" (PitNETs) was proposed in 2017 to reflect their characteristics as epithelial neuroendocrine neoplasms with a spectrum of clinical behaviors ranging from small indolent lesions to large, locally invasive, unresectable tumors. Tumor growth and hormone hypersecretion cause significant morbidity and mortality in a subset of patients. The proposal was endorsed by a WHO working group that sought to provide a unified approach to neuroendocrine neoplasia in all body sites. We review the features that are characteristic of neuroendocrine cells, the epidemiology and prognosis of these tumors, as well as further refinements in terms used for other pituitary tumors to ensure consistency with the WHO framework. The intense study of PitNETs has provided information about the importance of cellular differentiation in tumor prognosis as a model for neuroendocrine tumors in different locations.
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| 7. |
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| 8. |
- Aydin, Nursah, et al.
(författare)
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Ameliorative Effects by Hexagonal Boron Nitride Nanoparticles against Beta Amyloid Induced Neurotoxicity
- 2022
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 12:15, s. 2690-
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is considered as the most common neurodegenerative disease. Extracellular amyloid beta (A beta) deposition is a hallmark of AD. The options based on degradation and clearance of A beta are preferred as promising therapeutic strategies for AD. Interestingly, recent findings indicate that boron nanoparticles not only act as a carrier but also play key roles in mediating biological effects. In the present study, the aim was to investigate the effects of different concentrations (0-500 mg/L) of hexagonal boron nitride nanoparticles (hBN-NPs) against neurotoxicity by beta amyloid (A beta(1-42)) in differentiated human SH-SY5Y neuroblastoma cell cultures for the first time. The synthesized hBN-NPs were characterized by X-ray diffraction (XRD) measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A beta(1-42)-induced neurotoxicity and therapeutic potential by hBN-NPs were assessed on differentiated SH-SY5Y cells using MTT and LDH release assays. Levels of total antioxidant capacity (TAC) and total oxidant status (TOS), expression levels of genes associated with AD and cellular morphologies were examined. The exposure to A beta(1-42) significantly decreased the rates of viable cells which was accompanied by elevated TOS level. A beta(1-42) induced both apoptotic and necrotic cell death. A beta exposure led to significant increases in expression levels of APOE, BACE 1, EGFR, NCTSN and TNF-alpha genes and significant decreases in expression levels of ADAM 10, APH1A, BDNF, PSEN1 and PSENEN genes (p < 0.05). All the A beta(1-42)-induced neurotoxic insults were inhibited by the applications with hBN-NPs. hBN-NPs also suppressed the remarkable elevation in the signal for A beta following exposure to A beta(1-42) for 48 h. Our results indicated that hBN-NPs could significantly prevent the neurotoxic damages by A beta. Thus, hBN-NPs could be a novel and promising anti-AD agent for effective drug development, bio-nano imaging or drug delivery strategies.
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| 9. |
- Azharuddin, Mohammad, 1986-, et al.
(författare)
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A repertoire of biomedical applications of noble metal nanoparticles
- 2019
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:49, s. 6964-6996
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Forskningsöversikt (refereegranskat)abstract
- Noble metals comprise any of several metallic chemical elements that are outstandingly resistant to corrosion and oxidation, even at elevated temperatures. This group is not strictly defined, but the tentative list includes ruthenium, rhodium, palladium, silver, osmium, iridium, platinum and gold, in order of atomic number. The emerging properties of noble metal nanoparticles are attracting huge interest from the translational scientific community and have led to an unprecedented expansion of research and exploration of applications in biotechnology and biomedicine. Noble metal nanomaterials can be synthesised both by top-down and bottom up approaches, as well as via organism-assisted routes, and subsequently modified appropriately for the field of use. Nanoscale analogues of gold, silver, platinum, and palladium in particular, have gained primary importance owing to their excellent intrinsic properties and diversity of applications; they offer unique functional attributes, which are quite unlike the bulk material. Modulation of noble metal nanoparticles in terms of size, shape and surface functionalisation has endowed them with unusual capabilities and manipulation at the chemical level, which can lead to changes in their electrical, chemical, optical, spectral and other intrinsic properties. Such flexibility in multi-functionalisation delivers Ockhams razor to applied biomedical science. In this feature article, we highlight recent advances in the adaptation of noble metal nanomaterials and their biomedical applications in therapeutics, diagnostics and sensing.
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| 10. |
- bazargan, mohsen
(författare)
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Thermal fluid circulation around the Karliova triple junction: Geochemical features and volcano-tectonic implications (Eastern Turkey)
- 2019
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Ingår i: Geothermics. - : Elsevier BV. - 0375-6505.
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Tidskriftsartikel (refereegranskat)abstract
- The Karlıova triple junction (KTJ) in eastern Turkey has been subjected to incremental deformation resulting in complex kinematic and mechanical interactions throughout the upper crust. These interactions have generated tectonic inversions and uplift, extensive seismicity and volcanism. The regional tectonics generate local stresses, some of which are favourable to magma transport and thermal water circulation throughout the lithosphere. Here we evaluate hydrogeochemical, geological and numerical results relating to the mechanism of thermal fluid circulation around the KTJ. Hydrogeochemistry of the samples indicates that the thermal water springs are probably heated by steam. Volcanic rocks at the site appear to be the host rock owing to the enrichment of Na+ and Cl− ions in water and the abundance of these elements in minerals of the volcanic rocks. In addition, it is clear that the thermal fluids are sourced from the depth and migrate through permeable networks of faults. The effects of crustal heterogeneities, in particular the geometry and mechanical properties of many faults and layers, on thermal fluid circulation in relation to active magma chambers were investigated under a variety of different mechanical conditions. The numerical results indicate very close relationships between the stress field causing faulting and thermal fluid movement in the KTJ. The effect of thermal transfer was modelled with depth throughout the crust and along the crustal surface. The models show that some faults encourage thermal fluid circulation below the Varto and Özenç volcanoes. Hydrogeochemical, geological and numerical results suggest that magmas residing beneath both the Varto caldera and the Özenç volcano are the main heat source for thermal fluid in the Varto region. Fluid-solid interactions and fluid circulation models show that permeable faults are important factors affecting heat transport and fluid circulation. In a series of thermal fluid flow models we probe the mechanism for fluid and gas transport from the 900 °C ‘hot’ zone around the deep magma chambers and investigate how heat is lost throughout the crust on the way to the surface and so eventually creates water channels of temperatures between 50 to 60 °C.
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