| 1. |
- Backenius, Erik, 1974-
(författare)
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On Reduction of Substrate Noise in Mixed-Signal Circuits
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Microelectronics is heading towards larger and larger systems implemented on a single chip. In wireless communication equipment, e.g., cellular phones, handheld computers etc., both analog and digital circuits are required. If several integrated circuits (ICs) are used in a system, a large amount of the power is consumed by the communication between the ICs. Furthermore, the communication between ICs is slow compared with on-chip communication. Therefore, it is favorable to integrate the whole system on a single chip, which is the objective in the system-on-chip (SoC) approach.In a mixed-signal SoC, analog and digital circuits share the same chip. When digital circuits are switching, they produce noise that is spread through the silicon substrate to other circuits. This noise is known as substrate noise. The performance of sensitive analog circuits is degraded by the substrate noise in terms of, e.g., lower signal-to-noise ratio and lower spurious-free dynamic range. Another problem is the design of the clock distribution net, which is challenging in terms of obtaining low power consumption, sharp clock edges, and low simultaneous switching noise.In this thesis, a noise reduction strategy that focus on reducing the amount of noise produced in digital clock buffers, is presented. The strategy is to use a clock with long rise and fall times. It is also used to relax the constraints on the clock distribution net, which also reduce the design effort. Measurements on a test chip show that the strategy can be implemented in an IC with low cost in terms of speed and power consumption. Comparisons between substrate coupling in silicon-on-insulator (SOI) and conventional bulk technology are made using simple models. The objective here is to get an understanding of how the substrate coupling differs in SOI from the bulk technology. The results show that the SOI has less substrate coupling when no guard band is used, up to a certain frequency that is highly dependent of the chip structure. When a guard band is introduced in one of the analyzed test structures, the bulk resulted in much higher attenuation compared with SOI. An on-chip measurement circuit aiming at measuring simultaneous switching noise has also been designed in a 0.13 µ SOI process.
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| 2. |
- Brodszki, Nicholas, et al.
(författare)
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A novel treatment approach for paediatric Gorham-Stout syndrome with chylothorax
- 2011
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Ingår i: Acta Pædiatrica. - : Wiley. - 1651-2227 .- 0803-5253. ; 100:11, s. 1448-1453
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To expand the treatment options in paediatric Gorham-Stout syndrome (GSS) when conventional therapy is ineffective. Method: Two children with biopsy confirmed GSS, a rare disorder with progressive lymphangiomatosis, were treated with a combination of interferon-alpha-2b, low anticoagulant, low molecular weight heparin, radiotherapy and surgery. Results: The combined therapy resolved the symptoms in the acute phase, and both patients have since been free of symptoms for >2 years. Conclusion: The successful addition of a low anticoagulant, low molecular weight heparin ( tafoxiparin) to the treatment protocol in two paediatric cases of the GSS may justify the use of this approach in similar cases.
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| 3. |
- Ekström, Erik, 1989-
(författare)
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Growth and thermoelectric properties of CaMnO3-based thin films
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The field of them1oelectrics started in early 19th century. Since the discovery of the Seebeck effect and the Peltier effect, thermoelectric modules have found their way into, mostly, niche applications such as radioisotope thermoelectric generators on space missions. Thermoelectric modules can also be used for cooling, utilizing the Peltier effect.Thermoelectrics are promising materials due to the operation nature of the modules. That is, they have no moving parts, no exhaust, long lifetime without maintenance, features that make them attractive for many applications. Despite these promising properties, thermoelectric modules are mostly used in niche applications. The main reason for this is conventional modules with the highest efficiency are commonly made of expensive and/or rare elements which prevents mass production.To tackle this problem, new materials are investigated to find a module that can be made widely available. Oxides are one possibility, where an added benefit is that they are chemically stable even at elevated temperature. The perovskite CaMnO3 is one of the more promising oxides, with elements that are abundant on earth and cheap. The material does suffer from low electrical conductivity which results in a low electrical conductivity and efficiency. A substantial effort has been put in to increase the efficiency of CaMnO3, hut it still needs improvement.In my thesis, I have investigated the CaMnO3 system. CaMnO3 was synthesized using co-reactive RF-magnetron sputtering and post annealing. The synthesis method is already known hut has not been used for deposition of perovskites. I have also demonstrated that this synthesis method can be used to dope CaMnO3 with niobium at appropriate levels for enhancing the efficiency.
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| 4. |
- Elbornsson, Jonas, et al.
(författare)
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Analysis of Mismatch Effects in Randomly Interleaved A/D Converter System
- 2005
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Ingår i: IEEE Transactions on Circuits And Systems Part I. - : Institute of Electrical and Electronics Engineers (IEEE). - 1057-7122 .- 1558-1268. ; 52:3, s. 465-476
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Tidskriftsartikel (refereegranskat)abstract
- To significantly increase the sampling rate of an A/D converter (ADC), a time interleaved ADC system is a good option. The drawback of a time interleaved ADC system is that the ADCs are not exactly identical due to errors in the manufacturing process. This means that time, gain and offset mismatch errors are introduced in the ADC system. These errors cause non harmonic distortion in the sampled signal. One way to decrease the impact of the mismatch errors is to spread the distortion over a wider frequency range by randomizing the order in which the ADCs are used in the interleaved structure. In this paper we analyze how the spectrum is affected by mismatch errors in a randomly interleaved ADC system. We also discuss how the mismatch errors can be estimated.
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| 5. |
- Engkvist, Inga-Lill, et al.
(författare)
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Joint investigation of working conditions, environmental and system performance at recycling centres : Development of instruments and their usage
- 2010
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 0003-6870 .- 1872-9126. ; 41:3, s. 336-346
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Tidskriftsartikel (refereegranskat)abstract
- Recycling is a new and developing industry, which has only been researched to a limited extent. This article describes the development and use of instruments for data collection within a multidisciplinary research programme "Recycling centres in Sweden - working conditions, environmental and system performance". The overall purpose of the programme was to form a basis for improving the function of recycling centres with respect to these three perspectives and the disciplines of: ergonomics, safety, external environment, and production systems. A total of 10 instruments were developed for collecting data from employees, managers and visitors at recycling centres. including one instrument for observing visitors. Validation tests were performed in several steps. This, along with the quality of the collected data, and experience from the data collection, showed that the instruments and methodology used were valid and suitable for their purpose.
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| 6. |
- Engkvist, Inga-Lill, 1950-, et al.
(författare)
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Planera, utforma och driva en återvinningscentral
- 2009
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Bok (populärvet., debatt m.m.)abstract
- Denna bok baserar sig på de forskningsresultat och erfarenheter som kommit fram inom forskningsprogrammet ”Framtidens återvinningscentral” som är ett multidiciplinärt forskningsprogram som drivits vid Linköpings universitet under åren 2002-2007.Boken vänder sig till alla som är involverade vid planering, byggnation, ombyggnation och drift av återvinningscentraler. Dessa kan vara ansvariga inom kommuner, arkitekter, konsulter, arbetsledare på återvinningscentral, skyddsombud, fackliga förtroendemän med flera.
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| 7. |
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| 8. |
- Galosi, Serena, et al.
(författare)
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De novo DHDDS variants cause a neurodevelopmental and neurodegenerative disorder with myoclonus
- 2022
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 145:1, s. 208-223
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Tidskriftsartikel (refereegranskat)abstract
- Subcellular membrane systems are highly enriched in dolichol, whose role in organelle homeostasis and endosomal-lysosomal pathway remains largely unclear besides being involved in protein glycosylation. DHDDS encodes for the catalytic subunit (DHDDS) of the enzyme cis-prenyltransferase (cis-PTase), involved in dolichol biosynthesis and dolichol-dependent protein glycosylation in the endoplasmic reticulum. An autosomal recessive form of retinitis pigmentosa (retinitis pigmentosa 59) has been associated with a recurrent DHDDS variant. Moreover, two recurring de novo substitutions were detected in a few cases presenting with neurodevelopmental disorder, epilepsy, and movement disorder. We evaluated a large cohort of patients (n=25) with de novo pathogenic variants in DHDDS and provided the first systematic description of the clinical features and long-term outcome of this new neurodevelopmental and neurodegenerative disorder. The functional impact of the identified variants was explored by yeast complementation system and enzymatic assay. Patients presented during infancy or childhood with a variable association of neurodevelopmental disorder, generalized epilepsy, action myoclonus/cortical tremor, and ataxia. Later in the disease course they experienced a slow neurological decline with the emergence of hyperkinetic and/or hypokinetic movement disorder, cognitive deterioration, and psychiatric disturbances. Storage of lipidic material and altered lysosomes were detected in myelinated fibers and fibroblasts, suggesting a dysfunction of the lysosomal enzymatic scavenger machinery. Serum glycoprotein hypoglycosylation was not detected and, in contrast to retinitis pigmentosa and other congenital disorders of glycosylation involving dolichol metabolism, the urinary dolichol D18/D19 ratio was normal. Mapping the disease-causing variants into the protein structure revealed that most of them clustered around the active site of the DHDDS subunit. Functional studies using yeast complementation assay and in vitro activity measurements confirmed that these changes affected the catalytic activity of the cis-PTase and showed growth defect in yeast complementation system as compared with the wild-type enzyme and retinitis pigmentosa-associated protein. In conclusion, we characterized a distinctive neurodegenerative disorder due to de novo DHDDS variants, which clinically belongs to the spectrum of genetic progressive encephalopathies with myoclonus. Clinical and biochemical data from this cohort depicted a condition at the intersection of congenital disorders of glycosylation and inherited storage diseases with several features akin to of progressive myoclonus epilepsy such as neuronal ceroid lipofuscinosis and other lysosomal disorders.
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| 9. |
- Malmström, Erik, et al.
(författare)
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The importance of fibroblasts in remodelling of the human uterine cervix during pregnancy and parturition.
- 2007
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Ingår i: Molecular Human Reproduction. - : Oxford University Press (OUP). - 1460-2407. ; 13, s. 333-341
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Tidskriftsartikel (refereegranskat)abstract
- It is well established that fibroblasts play a crucial role in pathophysiological extracellular matrix remodelling. The aim of this project is to elucidate their role in normal physiological remodelling. Specifically, the remodelling of the human cervix during pregnancy, resulting in an enabled passage of the child, is used as the model system. Fibroblast cultures were established from cervices of non-pregnant women, women after 36 weeks of pregnancy and women directly after partus. The cells were immunostained and quantified by western blots for differentiation markers. The cultures were screened for cytokine and metalloproteinase production and characterized by global proteome analysis. The cell cultures established from partal donors differ significantly from those from non-pregnant donors, which is in accordance with in vivo findings. A decrease in alpha-smooth actin and prolyl-4hydroxylase and an increase in interleukin (IL)-6, IL-8 and matrix metalloproteinases (MMP)-1 and MMP-3 were observed in cultures from partal donors. 2D-gel electrophoresis followed by mass spectrometry showed that the expression of 59 proteins was changed significantly in cultures of partal donors. The regulated proteins are involved in protein kinase C signalling, Ca2+ binding, cytoskeletal organization, angiogenesis and degradation. Our data suggest that remodelling of the human cervix is orchestrated by fibroblasts, which are activated or recruited by the inflammatory processes occurring during the ripening cascade.
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| 10. |
- Sundin, Erik, et al.
(författare)
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Improving the layout of recycling centres by use of lean production principles
- 2011
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Ingår i: WASTE MANAGEMENT. - : Elsevier Science B.V., Amsterdam.. - 0956-053X .- 1879-2456. ; 31:6, s. 1121-1132
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Tidskriftsartikel (refereegranskat)abstract
- There has been increased focus on recycling in Sweden during recent years. This focus can be attributed to external environmental factors such as tougher legislation, but also to the potential gains for raw materials suppliers. Recycling centres are important components in the Swedish total recycling system. Recycling centres are manned facilities for waste collection where visitors can bring, sort and discard worn products as well as large-sized, hazardous, and electrical waste. The aim of this paper was to identify and describe the main flows and layout types at Swedish recycling centres. The aim was also to adapt and apply production theory for designing and managing recycling centre operations. More specifically, this means using lean production principles to help develop guidelines for recycling centre design and efficient control. Empirical data for this research was primarily collected through interviews and questionnaires among both visitors and employees at 16 Swedish recycling centres. Furthermore, adapted observation protocols have been used in order to explore visitor activities. There was also close collaboration with a local recycling centre company, which shared their layout experiences with the researchers in this project. The recycling centres studied had a variety of problems such as queues of visitors, overloading of material and improper sorting. The study shows that in order to decrease the problems, the recycling centres should be designed and managed according to lean production principles, i.e. through choosing more suitable layout choices with visible and linear flows, providing better visitor information, and providing suitable technical equipment. Improvements can be achieved through proper planning of the layout and control of the flow of vehicles, with the result of increased efficiency and capacity, shorter visits, and cleaner waste fractions. The benefits of a lean production mindset include increased visitor capacity, waste flexibility, improved sorting quality, shorter time for visits and improved working conditions.
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