| 1. |
- Bränström, Robert, et al.
(författare)
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Electrical short-circuit in β-cells from a patient with non-insulinoma pancreatogenous hypoglycemic syndrome (NIPHS) : a case report
- 2010
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Ingår i: Journal of Medical Case Reports. - : Springer Science and Business Media LLC. - 1752-1947. ; 4:1, s. 315-
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Non-insulinoma pancreatogenous hypoglycemic syndrome is a rare disorder among adults, and, to our knowledge, only about 40 cases have been reported in the literature. CASE PRESENTATION: The patient is a previously healthy 35-year-old Caucasian man. His symptoms began four years ago when he suddenly felt weakness in his legs and started sweating for unknown reasons. The symptoms worsened, and laboratory tests revealed hypoglycemia and hyperinsulinemia at the time of the symptoms. All diagnostics attempts using magnetic resonance imaging, computed tomography, and endoscopic ultrasound did not reveal any abnormalities. At this stage, surgical intervention was planned, and a distal 80% pancreatectomy was performed. The histopathologic and immunohistochemical investigations of the pancreas showed an increased number of islets of different sizes, more or less evenly distributed in the gland, but no insulinoma. Patch-clamp recordings from isolated pancreatic β-cells showed that, even at a low glucose concentration (3 mmol/L), the β-cell membrane was depolarized, and action potentials were seen. Surprisingly, in patch-clamp experiments, the addition of diazoxide had a marked effect on K-ATP channel activity and membrane potential, but no effect on insulin levels in vivo before surgery. CONCLUSION: This case report adds new information on the pathogenesis of non-insulinoma pancreatogenous hypoglycemic syndrome, as we performed an electrophysiologic characterization of isolated islet cells. We show, for the first time, that β-cells isolated from a non-insulinoma pancreatogenous hypoglycemic syndrome patient are constantly depolarized, even at low glucose levels, but display normal K-ATP channel physiology.
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| 2. |
- Avall, Karin, et al.
(författare)
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Apolipoprotein CIII links islet insulin resistance to beta-cell failure in diabetes
- 2015
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:20, s. E2611-E2619
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Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance and beta-cell failure are the major defects in type 2 diabetes mellitus. However, the molecular mechanisms linking these two defects remain unknown. Elevated levels of apolipoprotein CIII (apoCIII) are associated not only with insulin resistance but also with cardiovascular disorders and inflammation. We now demonstrate that local apoCIII production is connected to pancreatic islet insulin resistance and beta-cell failure. An increase in islet apoCIII causes promotion of a local inflammatory milieu, increased mitochondrial metabolism, deranged regulation of beta-cell cytoplasmic free Ca2+ concentration ([Ca2+](i)) and apoptosis. Decreasing apoCIII in vivo results in improved glucose tolerance, and pancreatic apoCIII knockout islets transplanted into diabetic mice, with high systemic levels of the apolipoprotein, demonstrate a normal [Ca2+](i) response pattern and no hallmarks of inflammation. Hence, under conditions of islet insulin resistance, locally produced apoCIII is an important diabetogenic factor involved in impairment of beta-cell function and may thus constitute a novel target for the treatment of type 2 diabetes mellitus.
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| 3. |
- Axsäter, Sven, et al.
(författare)
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Comparison of Echelon Stock and Installation Stock Policies for Two-Level Inventory Systems
- 1996
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Ingår i: International Journal of Production Economics. - : Elsevier BV. - 0925-5273 .- 1873-7579. ; 45:1-3, s. 303-310
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Tidskriftsartikel (refereegranskat)abstract
- It is previously known that echelon stock reorder point policies dominate installation stock reorder point policies for serial and assembly multi-level inventory systems. This paper presents worst-case results for the relative cost difference in case of constant demand and no backorders. Furthermore, we analyze distribution systems with stochastic demand by simulation. Depending on the structure of the system either echelon stock or installation stock policies may be advantageous.
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| 4. |
- Axsäter, Sven, et al.
(författare)
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Comparison of echelon stock and installation stock policies with policy adjusted order quantities
- 1997
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Ingår i: International Journal of Production Economics. - 0925-5273 .- 1873-7579. ; 48:1, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Echelon stock and installation stock reorder point policies for multi-level inventory control have been compared in previous studies. It is known that echelon stock policies dominate installation stock policies for serial and assembly systems. Earlier comparisons assume that both policies use the same given order quantities, while each policy is optimized with respect to its reorder points. This paper presents worst case results for the cost ratio when the order quantities can be optimized for each policy.
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| 7. |
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| 8. |
- Tiensuu, Kiira, et al.
(författare)
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RAVEN: a student rocket program at Luleå University of Technology, Sweden
- 2021
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Ingår i: IAC 2021 Congress Proceedings, 72nd International Astronautical Congress (IAC), Dubai, United Arab Emirates. - : International Astronautical Federation (IAF).
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Konferensbidrag (refereegranskat)abstract
- RAVEN, Rocketry and Aerospace Vehicle Engineering in Norrbotten, is the first rocket project at Luleå University of Technology (LTU), Sweden. The project started in early 2020, and it aims to design, build, test and launch a hybrid propulsion rocket. The initial objectives are to reach an altitude of 10 km with an accompanying payload of 10 kg. The RAVEN team is based at the Kiruna Space Campus and consists of approximately 30 graduate students. The main goal of the first RAVEN rocket is to demonstrate its technology. The team is designing the entire rocket from scratch, including the hybrid propulsion system that uses nitrous oxide as the oxidising agent and paraffin as the solid fuel component, to produce approximately 6 kN of thrust. A modular rocket structure will offer customisation, enabling simple design changes in future iterations. Thus, the layout allows individual subsystems to be re-designed without changes directly affecting others. The project is meant to create a foundation for future student and research rocket projects at LTU. The follow-up developments could further iterate on the first rocket design, increasing hands-on education and providing more collaboration opportunities between the university and the aerospace industry – and eventually provide an in-house platform for research and education at the university or even for commercial start-ups. The infrastructure and resources, such as the proximity to the Esrange Space Center launch facility and support from the university and industry, make Northern Sweden an ideal location to establish a continuous rocket program.
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| 9. |
- Wågberg, Lars, et al.
(författare)
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Engineering of fibre surface properties by application of the polyelectrolyte multilayer concept. Part I : Modification of paper strength
- 2002
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Ingår i: Journal of Pulp and Paper Science (JPPS). - 0826-6220. ; 28:7, s. 222-228
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Tidskriftsartikel (refereegranskat)abstract
- Consecutive layers of cationic polyallylamine and anionic polyacrylic acid have been deposited on both unbeaten and beaten fully bleached cellulosic fibres. By preparing sheets of these fibres and by forming 5-10 layers of these polyelectrolytes on the unbeaten fibres, it was possible to develop the same strength as can be achieved by conventional beating. Experiments show that considerable strength improvement can be achieved with this type of treatment also on beaten fibres. Atomic force microscopy investigations of multilayers of the polylectrolytes formed on silicon oxide surfaces showed that the thickness of 10 layers of polyelectrolytes was 52 nm. Since the strength improvement was significant with 5 layers, it is suggested that a 26 nm thick multilayer of polyelectrolytes is sufficient to create a strong joint between fibres. The structure of the polyelectrolyte multilayers formed on the fibres was not determined.
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