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- Annebäck, Matilda, et al.
(författare)
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Validating the risk of hypoparathyroidism after total thyroidectomy in a population-based cohort : plea for improved follow-up
- 2024
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Ingår i: British Journal of Surgery. - : Oxford University Press. - 0007-1323 .- 1365-2168. ; 111:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundA previous nationwide study from Sweden showed that the rate of permanent hypoparathyroidism is high and under-rated in the Swedish Quality Register. This retrospective population-based study aimed to validate the rate and diagnosis of permanent hypoparathyroidism found in the previous study. A secondary aim was to assess the relationship between the rate of low parathyroid hormone (PTH) levels within 24 h after surgery and the rate of permanent hypoparathyroidism.MethodsAll patients who underwent total thyroidectomy from 2005 to 2015 in a region of Sweden were included. Data were retrieved from local health records, the National Patient Registry, the Swedish Prescribed Drug Registry, and the Swedish Quality Register. A strict definition of permanent hypoparathyroidism was used, including biochemical data and attempts to stop the treatment.ResultsA total of 1636 patients were included. Altogether, 143 patients (8.7 per cent) developed permanent hypoparathyroidism. Of these, 102 (6.2 per cent) had definitive permanent hypoparathyroidism, whereas 41 (2.5 per cent) had possible permanent hypoparathyroidism, because attempts to stop the treatment were lacking (28) or patients were lost to follow-up (13). The agreement between the Swedish Quality Register and the chart review was 29.3 per cent. A proportion of 23.2 per cent with a PTH level below the reference value corresponded to a 6.7 per cent rate of permanent hypoparathyroidism.ConclusionThe risk of permanent hypoparathyroidism after total thyroidectomy is high. Some patients are overtreated because attempts to stop the treatment are lacking. Quality registers might underestimate the risk of permanent hypoparathyroidism. Approximately one-quarter of all patients with low PTH levels immediately after surgery developed permanent hypoparathyroidism.
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| 4. |
- Osterman, Jesper, 1971-
(författare)
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Investigations of Optical Properties and Photo-Alignment in Bistable Nematic Liquid Crystal Displays
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years portable electronic devices, such as mobile phones and personal digital assistants, have increased the demand for high performance displays with low power consumption. An interesting candidate with the potential of fulfilling these demands is the reflective single-polarizer surface controlled bistable twisted nematic liquid crystal display. The main focus of this work involves the optical properties of displays based on these bistable structures. In the investigations, the display is considered as an integrated optical system, containing not only the liquid crystal cell, but also components such as polarizers and retardation films. The specific aim of the thesis was to derive new optical modes of the reflective single-polarizer bistable twisted nematic device using the Jones matrix method to study the interaction between the polarization of light and the optically anisotropic media. The electro-optical properties of the derived modes have been studied and evaluated both theoretically and experimentally. The modes possess excellent brightness and high contrast ratio. By introducing a quarter-wave retardation film into the optical configuration, the contrast ratio can be significantly increased by preventing spectral leakage of light in the dark state. To experimentally realize the derived optical modes, special layers for the alignment of the liquid crystal molecules on the cell substrate surface have been proved needed. Therefore, also the photo-alignment technology of nematic liquid crystals on novel alignment materials has been studied with the aim to control liquid crystal cell parameters such as pretilt angle and anchoring energy, both critical for the bistable switching. The results of this thesis will increase the understanding of the optical properties of the reflective single-polarizer bistable twisted nematic liquid crystal display and will be valuable when considering this type of device for practical applications.
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| 5. |
- Osterman, Jesper, et al.
(författare)
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Mechanically stabilized bistable FLC cells on plastic substrates
- 2005
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Ingår i: Proceedings of the twenty-fifth international display research conference, Eurodisplay 2005.
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Konferensbidrag (refereegranskat)abstract
- The electro-optical properties of a full v flexible photo-aligned FLC cell are investigated. Two different methods, sticky spacers together with a photo-sensitive monomer and polymer spacers in a regular pattern formed by photo-lithography, are proposed to stabilize the structure in order to increase the bending tolerance of the FLC material during deformation of the cell.
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| 7. |
- Osterman, Jesper, et al.
(författare)
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Optical Modes for Single Polarizer Reflective BTN
- 2002
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Ingår i: Proceedings of the 22nd International Display Research Conference, Eurodisplay, Nice, France. - Nice, France. ; , s. 479-
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Tidskriftsartikel (refereegranskat)
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| 11. |
- Osterman, Jesper, et al.
(författare)
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Properties of azo-dye alignment layer on plastic substrates
- 2005
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Ingår i: Journal of the Society for Information Display. - : Wiley. - 1071-0922 .- 1938-3657. ; 13:12, s. 1003-1009
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Tidskriftsartikel (refereegranskat)abstract
- The alignment properties of the azo dye photo-alignment material SD-1/SDA-2 on plastic substrates are investigated. Excellent alignment with high anchoring energy can be achieved with a polarized UV dose less than 1.0 J/cm2. A reflective 6-digit flexible passive matrix driven TN-LCD for smart card applications showing excellent electro-optical properties is demonstrated.
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| 14. |
- Selo Mustafa, Muhammed, et al.
(författare)
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Synthesis, spectroscopic characterisation and alignment of novel azobenzene containing monomers
- 2005
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Ingår i: Liquid crystals (Print). - : Informa UK Limited. - 0267-8292 .- 1366-5855. ; 32:7, s. 901-908
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Tidskriftsartikel (refereegranskat)abstract
- A series of novel bifunctionalized photochromic monomers were synthesized, focusing on those with polymerizable acrylic/methacrylic groups attached to both ends of an azobenzene core via flexible spacers. The phase behaviour of the monomers was investigated using DSC, polarizing optical microscopy and X‐ray diffraction. The change in UV‐vis absorbance of the monomers under illumination with non‐polarized/polarized UV light was studied for both solutions and thin films; also studied was its relaxation in the dark. On illumination with LPUV light, in‐plane reorientation of the molecules normal to the polarization of the exciting UV light, and aggregation of the molecules in the films, were found.
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| 21. |
- Valyukh, Sergiy, et al.
(författare)
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Characterization of flexible reflective liquid crystal cells
- 2005
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Ingår i: Journal of the Society for Information Display. - : Wiley. - 1071-0922 .- 1938-3657. ; 13:6, s. 501-506
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Tidskriftsartikel (refereegranskat)abstract
- We consider peculiarities in testing flexible reflective liquid-crystal (LC) cells. Several new methods for measuring optical retardation of filled reflective LC cells on plastic substrates are proposed. Cases when the plastic is anisotropic and the LC cell consists of either one or two internal polarizers are studied. The majority of proposed methods can be applied for transmissive LC cells as well as for measuring twist angle.
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- Wang, Kun, et al.
(författare)
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Perception and annoyance of crosstalk in stereoscopic 3D projector systems
- 2014
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - Bellingham, WA, USA : SPIE. - 9780819499288 ; , s. 901125-
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Konferensbidrag (refereegranskat)abstract
- Crosstalk is a cause of a major perceptual problem in the 3D display system shown itself mostly as ghosting. In this work we aimed at investigating how much perceived crosstalk that is acceptable for the end-users in movie type contents played by 3D projection systems. Two types of 3D projection systems (one system using active shutter glasses, and the other system using passive polarized glasses) were compared in the experiment. The study included an objective measurement of crosstalk in the 3D projection system and a subjective users' experience of the visible distortions. The results shows that 10% can be considered as a crosstalk threshold for end-users not to be annoyed (MOS<3.5) by the distortions and thus acceptable. The distortions start to be perceived at about 3% crosstalk. The study found a linear relationship between perceived crosstalk and the amount of crosstalk. The perceived crosstalk also varies largely depending on the video contents.
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