| 1. |
- Andersson, Erik, 1966, et al.
(författare)
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Konsumtionens finansialisering
- 2014
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Ingår i: Konsumtionsrapporten 2014. - Göteborg : University of Gothenburg. ; , s. 35-39
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Fredriksson, Ingemar, 1980-, et al.
(författare)
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Inverse Monte Carlo in a multilayered tissue model: merging diffuse reflectance spectroscopy and laser Doppler flowmetry
- 2013
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Ingår i: Journal of Biomedical Optics. - Bellingham, WA, United States : SPIE - International Society for Optical Engineering. - 1083-3668 .- 1560-2281. ; 18:12, s. 127004-1-127004-14
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Tidskriftsartikel (refereegranskat)abstract
- The tissue fraction of red blood cells (RBCs) and their oxygenation and speed-resolved perfusion areestimated in absolute units by combining diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry(LDF). The DRS spectra (450 to 850 nm) are assessed at two source–detector separations (0.4 and 1.2 mm), allowingfor a relative calibration routine, whereas LDF spectra are assessed at 1.2mmin the same fiber-optic probe. Data areanalyzed using nonlinear optimization in an inverse Monte Carlo technique by applying an adaptive multilayeredtissue model based on geometrical, scattering, and absorbing properties, as well as RBC flow-speed information.Simulations of 250 tissue-like models including up to 2000 individual blood vessels were used to evaluatethe method. The absolute root mean square (RMS) deviation between estimated and true oxygenation was 4.1percentage units, whereas the relative RMS deviations for the RBC tissue fraction and perfusion were 19% and23%, respectively. Examples of in vivo measurements on forearm and foot during common provocations arepresented. The method offers several advantages such as simultaneous quantification of RBC tissue fractionand oxygenation and perfusion from the same, predictable, sampling volume. The perfusion estimate is speedresolved, absolute (% RBC × mm∕s), and more accurate due to the combination with DRS.
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| 3. |
- Fredriksson, Ingemar, 1980-, et al.
(författare)
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Laser doppler flowmetry
- 2012
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Ingår i: Microcirculation imaging. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 3527328947 - 9783527328949 - 9783527651238 ; , s. 67-86
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Adopting a multidisciplinary approach with input from physicists, researchers and medical professionals, this is the first book to introduce many different technical approaches for the visualization of microcirculation, including laser Doppler and laser speckle, optical coherence tomography and photo-acoustic tomography. It covers everything from basic research to medical applications, providing the technical details while also outlining the respective strengths and weaknesses of each imaging technique. Edited by an international team of top experts, this is the ultimate handbook for every clinician and researcher relying on microcirculation imaging.
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| 4. |
- Green, Rikard, et al.
(författare)
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Pricing electricity swaptions under a stochastic volatility term structure model
- 2013
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Ingår i: Journal of Energy Markets. - : Incisive Media Investments Ltd.. - 1756-3607 .- 1756-3615. ; 6:4, s. 43-67
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Tidskriftsartikel (refereegranskat)abstract
- This paper suggests a stochastic volatility term structure model applied to the pricing of electricity swaptions in the Nordic power market traded at the Nasdaq OMX Commodities exchange. The volatility structure in the model is specified as a product of a time-dependent function, which handles the maturity effect, and a Cox-Ingersoll-Ross process for the stochastic volatility. We employ a Fourier-based approach to pricing electricity swaptions and perform an empirical analysis by calibrating the model to a data set consisting of more than 12 000 pairs of implied bid-ask volatilities, corresponding to swaption prices from the Nordic power market. We show that our model outperforms the lognormal benchmark both in- and out-of-sample.
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| 5. |
- Larsson, Karl, 1974-, et al.
(författare)
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Jumps and stochastic volatility in oil prices : Time series evidence
- 2011
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Ingår i: Energy Economics. - : Elsevier. - 0140-9883 .- 1873-6181. ; 33:3, s. 504-514
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we examine the empirical performance of affine jump diffusion models with stochastic volatility in a time series study of crude oil prices. We compare four different models and estimate them using the Markov Chain Monte Carlo method. The support for a stochastic volatility model including jumps in both prices and volatility is strong and the model clearly outperforms the others in terms of a superior fit to data. Our estimation method allows us to obtain a detailed study of oil prices during two periods of extreme market stress included in our sample; the Gulf war and the recent financial crisis. We also address the economic significance of model choice in two option pricing applications. The implied volatilities generated by the different estimated models are compared and we price a real option to develop an oil field. Our findings indicate that model choice can have a material effect on the option values.
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| 6. |
- Pettersson, Camilla, 1978, et al.
(författare)
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LDL-associated apolipoprotein J and lysozyme are associated with atherogenic properties of LDL found in type 2 diabetes and the metabolic syndrome.
- 2011
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Ingår i: Journal of internal medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 269:3, s. 306-321
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Exchangeable low-density lipoprotein (LDL)-associated proteins can affect the atherogenic properties of LDL. Our aim was to analyze the protein composition of LDL from individuals with or without type 2 diabetes and the metabolic syndrome (T2DM) in relation to other LDL-particle characteristics, to assess whether certain proteins associate more with certain subclasses of LDL typical for T2DM, such as small, apoCIII-rich LDL. Design LDL from two cohorts of 61-year-old men (n = 19 and 64) with or without T2DM was isolated using size-exclusion chromatography or deuterium oxide-based ultracentrifugation. LDL-associated proteins were identified using mass spectrometry and quantified using two-dimensional gel electrophoresis or enzyme-linked immunosorbent assay. Differently expressed LDL-associated proteins apolipoprotein (apo)J and lysozyme were also measured in serum from a third cohort of women (n = 71) with or without T2DM. Lysozyme binding to advanced glycation end product (AGE)-LDL was examined in vitro. Results ApoJ and lysozyme were increased in LDL particles with increased apoCIII content and decreased cholesterol content. When isolated with SEC, LDL from individuals with T2DM contained more apoJ and lysozyme and less apoA1 than LDL from control individuals. LDL content of apoJ correlated with a smaller LDL-particle size. Serum levels of lysozyme, but not apoJ, were increased in individuals with T2DM. In vitro, lysozyme associated more with AGE-LDL than with unmodified LDL. Conclusions Our results indicate that apoJ and lysozyme are increased in LDL with characteristics of small dense LDL in T2DM. Small dense LDL is easily glycated, and the increased affinity of lysozyme for AGE-LDL provides a possible partial explanation for an increase of lysozyme from those with type 2 diabetes.
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| 7. |
- Shi, Yonghong, et al.
(författare)
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Mammalian transcription factor A is a core component of the mitochondrial transcription machinery
- 2012
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Ingår i: Proceedings of the National Academy of Science of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:41, s. 16510-16515
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Tidskriftsartikel (refereegranskat)abstract
- Transcription factor A (TFAM) functions as a DNA packaging factor in mammalian mitochondria. TFAM also binds sequence-specifically to sites immediately upstream of mitochondrial promoters, but there are conflicting data regarding its role as a core component of the mitochondrial transcription machinery. We here demonstrate that TFAM is required for transcription in mitochondrial extracts as well as in a reconstituted in vitro transcription system. The absolute requirement of TFAM can be relaxed by conditions that allow DNA breathing, i.e., low salt concentrations or negatively supercoiled DNA templates. The situation is thus very similar to that described in nuclear RNA polymerase II-dependent transcription, in which the free energy of supercoiling can circumvent the need for a subset of basal transcription factors at specific promoters. In agreement with these observations, we demonstrate that TFAM has the capacity to induce negative supercoils in DNA, and, using the recently developed nucleobase analog FRET-pair tC(O)-tC(nitro), we find that TFAM distorts significantly the DNA structure. Our findings differ from recent observations reporting that TFAM is not a core component of the mitochondrial transcription machinery. Instead, our findings support a model in which TFAM is absolutely required to recruit the transcription machinery during initiation of transcription.
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| 8. |
- Strömberg, Tomas, 1966-, et al.
(författare)
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Experimental results using a three-layer skin model for diffuse reflectance spectroscopy
- 2013
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Ingår i: Optical Tomography and Spectroscopy of Tissue X. - : SPIE - International Society for Optical Engineering. - 9780819493477 ; , s. 857834-1-857834-8
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We have previously presented an inverse Monte Carlo algorithm based on a three-layer semi-infinite skin model for analyzing diffuse reflectance spectroscopy (DRS) data. The algorithm includes pre-simulated Monte Carlo data for a range of physiologically relevant epidermal thicknesses and tissue scattering levels. The simulated photon pathlength distributions in each layer are stored and the absorption effect from tissue chromophores added in the post-processing. Recorded DRS spectra at source-detector distances of 0.4 and 1.2 mm were calibrated for the relative intensity between the two distances and matched to simulated spectra in a non-linear optimization algorithm. This study evaluates the DRS spectral fitting accuracy and presents data on the main output parameters; the tissue fraction of red blood cells and local oxygenation (SO2). As a reference, the microcirculatory perfusion (Perf) was measured simultaneously in the same probe using laser Doppler Flowmetry. Data were recorded on the volar forearm of three healthy subjects in a protocol involving a 5 min systolic occlusion. The DRS spectra were modeled with an rms-error < 2%. In two subjects, SO2 decreased during occlusion to <10%, and increased to above baseline after hyperemia, while Perf increased >7 times compared to baseline. In the third subject the SO2 decreased less during occlusion and increased to baseline values at hyperemia with only a 2-fold increase in Perf. The observed difference could be due to different microvascular beds being probed. It is concluded that integrating DRS and LDF enables new possibilities to deduce microcirculation status.
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