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- Adnane, Bouchaib, et al.
(författare)
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Photoluminescence excitation spectroscopy of self-assembled SiGe/Si quantum dots
- 2009
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Photoluminescence excitation (PLE) experiments are reported for various self-assembled SiGe/Si dot samples grown on Si(001) by molecular beam epitaxy at substrate temperatures ranging from 430 to 580 C. Two excitation peaks were observed, and the characteristics of the involved optical transitions were studied in detail by PLE (in one case implemented together with selective photoluminescence, SPL) on different samples containing either only one SiGe dot layer or multiple SiGe-dot/Si stacks. The temperature- and power-dependence of the excitation properties together with the results of six-band k.p calculations support the assignment of the observed PLE peaks to spatially direct and indirect transitions collected from two different SiGe dot populations.
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| 2. |
- Ahlgren, Kerstin. M, et al.
(författare)
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Diabetes mellitus in dog - : No evidence for a type-1-like phenotype
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Aims/hypothesis Diabetes mellitus (DM) is one of the most common endocrine disorders in dogs, and is commonly proposed to be of autoimmune origin. Although the clinical symptoms of human type 1 diabetes (T1D) and canine DM are similar, the aetiologies may differ. The aim of this study was to investigate if autoimmune aetiology resembling human T1D is as prevalent in dogs as previously reported. Methods Sera from 121 diabetic dogs representing 38 different breeds were tested for islet cell antibodies (ICA) and GAD65 autoantibodies (GADA) and compared with sera from 133 healthy dogs from 40 breeds. ICA was detected by indirect immunofluorescence using both canine and human frozen sections. GADA was detected by in vitro transcription and translation (ITT) of human and canine GAD65, followed by immunoprecipitation. Results None of the canine sera analyzed tested positive for ICA on sections of frozen canine or human ICA pancreas. However, serum from one diabetic dog was weakly positive in the canine GADA assay and serum from one healthy dog was weakly positive in the human GADA assay. Conclusions/interpretations Based on sera from 121 diabetic dogs from 38 different breeds were tested for humoral autoreactivity using four different assays, contrary to previous observations, we find no support for an autoimmune aetiology in canine diabetes.
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| 3. |
- Ahlgren, Kerstin, M., et al.
(författare)
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Type I Interferon signature in Nova Scotia duck tolling retriever dogs with steroid responsive meningitis-arteritis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: Dogs of the breed Nova Scotia duck tolling retriever (NSDTR) are prone to develop a disease complex in some aspects resembling human systemic lupus erythematosus (SLE). Peripheral blood mononuclear cells (PBMCs) from human SLE patients have an increased mRNA expression type I interferon (IFN) regulated genes. However, it is unknown whether diseased dogs also display the typical type I IFN signature. Methods: To test canine sera for their capacity to induce type I IFN response Mardin-Darby canine kidney (MDCK) cells were cultured with sera from healthy dogs (n=25), immune-mediated rheumatic disease (IMRD) dogs with anti-nuclear antibodies (ANA+) (n=30) or dogs with steroid responsive meningitis-arteritis (SRMA) (n=25). mRNA expression of the genes MX1, IFIT1 and CXCL10 was measured by quantitative Real Time PCR. Results: A highly significant (p=0.0009) increase in mRNA expression of the type I IFN responsive gene MX1 was detected in cells stimulated by sera from dogs with SRMA, but not from IMRD ANA+ dogs. Expression of IFIT1 was twice as high in cells stimulated by sera from dogs with SRMA compared to both healthy dogs and ANA+ dogs. The mean expression of CXCL10 was nearly ten times higher in cells stimulated by sera from SRMA dogs than by ANA+ dogs and four times higher compared to cells stimulated by control dogs. Conclusion: Presence of type I IFN in sera from diseased NSDTR dogs was found in this study. This implies that this canine model can be used for identification of pathways of importance for autoimmune disorders in humans and for testing of novel therapeutic approaches. Our results can also be a step on the way towards personalized drugs in these dogs.
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| 4. |
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| 5. |
- Larsson, Mats, et al.
(författare)
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Band alignment studies in Si/Ge quantum dots based on optical and structural investigations
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The present work is a photoluminescence study of Si-embedded Stranski-Krastanov Ge quantum dots. The value of the conduction band offset is a result of the magnitude of the tensile strain in the Si surrounding the compressive strained Ge dot. Due to the increased Si/Ge intermixing and reduced strain in the Si barrier, a reduction of the conduction band offset is observed at increased growth temperatures. The optical properties as derived from photoluminescence spectroscopy are correlated with structural properties obtained as a function of the growth temperature. High growth temperatures result in large Ge dots with low density due to the pronounced surface diffusion and Si/Ge intermixing. As confirmed by photoluminescence, the band gap of the Ge dots increases with increased growth temperature due to the higher degree of Si/Ge intermixing. The band alignment is of type-II in these structures, but the occurrence of both spatially indirect and spatially direct transitions are confirmed in temperature dependent photoluminescence measurements with varied excitation power conditions. An increasing temperature results in a gradual transition from the spatially indirect to the spatially direct recombination in the type-II band lineup, due to higher oscillator strength for the spatially direct transition combined with a higher population factor at higher temperatures.
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| 8. |
- Svens, Pontus, et al.
(författare)
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Analysis of ageing of commercial composite metal oxide : Li4Ti5O12 battery cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Commercial battery cells with Li4Ti5O12 negative electrode and composite metal oxidepositive electrode have been analyzed with respect to ageing mechanisms. Electrochemical impedancespectroscopy (EIS), differential capacity analysis (dQ/dV), differential voltage analysis (dV/dQ) andscanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) were used to identifydifferent ageing mechanisms such as lithium inventory loss, loss of active electrode material andsurface film growth. The active material of the positive electrode was also examined by X-raydiffraction (XRD). Ageing mechanisms were studied for both calendar-aged and cycle-aged cells. Datafrom half cells prepared from post mortem harvested electrode material, using lithium foil as negativeelectrode and pouch material as encapsulation, were used as reference to full cell data. Electrochemicalanalysis of full and half cells combined with material analysis showed to be a powerful method toidentify ageing mechanisms in this type of commercial cells. The calendar-aged cell showedinsignificant ageing while the cycle-aged cell showed noticeable loss of positive electrode activematerial and loss of cyclable lithium, but only minor loss of negative electrode active material. Theresults imply that Li4Ti5O12 negative electrode material is a good alternative to other materials if highenergy density is not the primary goal.
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| 9. |
- Wallander, Henrik, et al.
(författare)
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Patient Reported Outcome at 62-67 years of age in 83 patients treated for Congenital Clubfoot
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Patient reported outcome in 83 patients with congenital clubfoot was evaluated at a mean age of 64 years using three validated questionnaires assessing both quality of life (SF-36 and EQ-5D) and foot and ankle function (AAOS Foot and Ankle Questionnaire). In SF-36 male patients scored significantly better than male norms in 7/8 domains, while female patients scored significantly worse than female norms in 2/8 domains. The male patients scored better than male norms in both EQ-5D Index (p=0.027) and VAS (p=0.013) while female patients scored worse than female norms in VAS (p<0.001). Both male and female patients had a significantly worse outcome on the AAOS Core Scale when compared to norms. There was a significant correlation, for both genders, between the SF-36 Physical Component Summary Score and the AAOS Core Scale. In conclusion the influence on daily life activities was limited to foot and ankle problems, and in female patients’ also in physical aspects of quality of life.
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