| 1. |
- Botling, Johan, et al.
(författare)
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Biomarker Discovery in Non-Small Cell Lung Cancer : Integrating Gene Expression Profiling, Meta-analysis, and Tissue Microarray Validation
- 2013
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 19:1, s. 194-204
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Global gene expression profiling has been widely used in lung cancer research to identify clinically relevant molecular subtypes as well as to predict prognosis and therapy response. So far, the value of these multigene signatures in clinical practice is unclear, and the biologic importance of individual genes is difficult to assess, as the published signatures virtually do not overlap.Experimental Design: Here, we describe a novel single institute cohort, including 196 non-small lung cancers (NSCLC) with clinical information and long-term follow-up. Gene expression array data were used as a training set to screen for single genes with prognostic impact. The top 450 probe sets identified using a univariate Cox regression model (significance level P < 0.01) were tested in a meta-analysis including five publicly available independent lung cancer cohorts (n = 860).Results: The meta-analysis revealed 14 genes that were significantly associated with survival (P < 0.001) with a false discovery rate < 1%. The prognostic impact of one of these genes, the cell adhesion molecule 1 (CADM1), was confirmed by use of immunohistochemistry on tissue microarrays from 2 independent NSCLC cohorts, altogether including 617 NSCLC samples. Low CADM1 protein expression was significantly associated with shorter survival, with particular influence in the adenocarcinoma patient subgroup.Conclusions: Using a novel NSCLC cohort together with a meta-analysis validation approach, we have identified a set of single genes with independent prognostic impact. One of these genes, CADM1, was further established as an immunohistochemical marker with a potential application in clinical diagnostics. Clin Cancer Res; 19(1); 194-204. (c) 2012 AACR.
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| 2. |
- Bornefalk, Hans, et al.
(författare)
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Effect of Temperature Variation on the Energy Response of a Photon Counting Silicon CT Detector
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9499 .- 1558-1578. ; 60:2, s. 1442-1449
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Tidskriftsartikel (refereegranskat)abstract
- The effect of temperature variation on pulse height determination accuracy is determined for a photon counting multibin silicon detector developed for spectral CT. Theoretical predictions of the temperature coefficient of the gain and offset are similar to values derived from synchrotron radiation measurements in a temperature controlled environment. By means of statistical modeling, we conclude that temperature changes affect all channels equally and with separate effects on gain and threshold offset. The combined effect of a 1 degrees C temperature increase is to decrease the detected energy by 0.1 keV for events depositing 30 keV. For the electronic noise, no statistically significant temperature effect was discernible in the data set, although theory predicts a weak dependence. The method is applicable to all x-ray detectors operating in pulse mode.
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| 3. |
- Chen, Han, et al.
(författare)
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A photon-counting silicon-strip detector for digital mammography with an ultrafast 0.18-mu m CMOS ASIC
- 2014
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 749, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- We have evaluated a silicon-strip detector with a 0.18-mu m CMOS application specific integrated circuits (ASIC) containing 160 channels for use in photon-counting digital mammography. Measurements were performed at the Elettra light source using monochromatic X-ray beams with different energies and intensities. Energy resolution, Delta E/E-in, was measured to vary between 0.10 and 0.23 in the energy range of 15-40 keV. Pulse pileup has shown little effect on energy resolution.
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| 4. |
- Dreifaldt, Mats, 1959-
(författare)
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Conduits in coronary artery bypass grafting surgery : Saphenous vein, radial and internal thoracic arteries
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A novel technique for saphenous vein (SV) graft harvesting, the No-touch technique (NT), has been developed at the Dept. of Cardiovascular surgery, Örebro University hospital. With NT the SV is harvested with a pedicle of surrounding tissue. This avoids graft spasm and eliminates the need for distension. The surrounding tissue acts as a structural support and is a rich source of vaso-dilating agents. A randomized controlled trial (RCT) has shown a significantly higher patency rate for NT SV grafts compared to SV grafts harvested with conventional technique (CT). This thesis evaluates some of the properties of the surrounding tissue and compares patency rates between NT SV and radial artery (RA) grafts and patency rates for internal thoracic artery (ITA) grafts harvested with and without surrounding tissue. Paper I investigated vasa vasorum (VV) in SV grafts and showed that the NT preserves an intact VV whereas CT does not. This could be one of the mechanisms underlying the improved patency for NT SV grafts. Paper II evaluated VV and associated nitric oxide (NO) in SV and arterial grafts. SV grafts showed a higher number and larger VV, which correlated with NO production, compared to arterial grafts. NT SV grafts showed higher activity for e-NOS compared to CT SV grafts. Paper III is a RCT comparing patency rates between NT SV and RA grafts, three years after surgery, showing a significantly higher patency rate for NT SV grafts. Paper IV is a RCT comparing patency rates for ITA graft harvested with and without surrounding tissue and did not show any difference between graft preparations. In conclusion, the NT for SV graft harvesting preserves an intact vasa vasorum and associated NO production. NT SV grafts show a higher patency rate than RA grafts. Harvesting of ITA with or without surrounding tissue does not affect patency rate.
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| 5. |
- Dreifaldt, Mats, et al.
(författare)
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The ‘‘no-touch’’ harvesting technique for vein grafts in coronary artery bypass surgery preserves an intact vasa vasorum
- 2011
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Ingår i: The Internet Journal of Thoracic and Cardiovascular Surgery. - New York, USA : Elsevier. - 1524-0274 .- 0022-5223. ; 141:1, s. 145-150
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Our objective was to evaluate the impact of vein graft harvesting technique on structure and function of vasa vasorum.Methods: Paired segments of great saphenous veins harvested either with conventional harvesting technique or no-touch technique were obtained from 9 consecutive patients undergoing coronary artery bypass grafting. Quantitative measurements, using immunohistochemistry and morphometry, were performed. Ultrastructural analyses of vasa vasorum were performed with electron microscopy. Video footage of superficial vasa vasorum in an implanted saphenous vein graft harvested with the no-touch technique was captured during a coronary bypass operation and is presented for online viewing.Results: The total area of vasa vasorum in vein grafts harvested with the conventional technique was significantly reduced both in the media (P¼.007) and in the adventitia (P¼.014) compared with vein grafts harvested with the no-touch technique. Ultrastructural findings indicated that the no-touch technique preserved an intact vasa vasorum whereas the conventional technique did not. Video footage showed retrograde flow in the vasa vasorum in vein graft harvested with the no-touch technique.Conclusions: These findings showthat the no-touch technique for saphenous vein graft harvesting for coronary bypass grafting preserves an intact vasa vasorum. This could represent one of the mechanisms underlying the improved patency of saphenous vein grafts harvested with this technique.
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| 6. |
- Falck, Eva, et al.
(författare)
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Loss of Glutathione peroxidase 3 expression is correlated with epigenetic mechanisms in endometrial adenocarcinoma
- 2010
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Ingår i: Cancer Cell International. - : BioMed Central (BMC). - 1475-2867. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Glutathione peroxidase 3 (GPX3) is one of the key enzymes in the cellular defense against oxidative stress and the hepatocyte growth factor receptor, (MET) has been suggested to be influenced by the GPX3 gene expression. In a previous microarray study performed by our group, Gpx3 was identified as a potential biomarker for rat endometrial adenocarcinoma (EAC), since the expression was highly downregulated in rat EAC tumors. Herein, we have investigated the mRNA expression and Gpx3 and Met in rat EAC by real time quantitative PCR (qPCR), and the methylation status of Gpx3. In addition we have examined the expression of GPX3 and MET in 30 human EACs of different FIGO grades and 20 benign endometrial tissues. We found that the expression of GPX3 was uniformly down regulated in both rat and human EAC, regardless of tumor grade or histopathological subtype, implying that the down-regulation is an early event in EAC. The rate of Gpx3 promoter methylation reaches 91%, where biallelic methylation was present in 90% of the methylated tumors. The expression of the Met oncogene was slightly upregulated in EACs that showed loss of expression of Gpx3, but no tumor suppressor activity of Gpx3/GPX3 was detected. Preliminary results also suggest that the production of H2O2 is higher in rat endometrial tumors with down-regulated Gpx3 expression. A likely consequence of loss of GPX3 protein function would be a higher amount of ROS in the cancer cell environment. Thus, the results suggest important clinical implications of the GPX3 expression in EAC, both as a molecular biomarker for EAC and as a potential target for therapeutic interventions.
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| 7. |
- Frogner, Kenneth, et al.
(författare)
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Towards manufacturing of perfect magnets
- 2010
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Ingår i: Proceeding of the conference on Flexible Automation and Intelligent Manufacturing, FAIM2010.
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedThe paper describes a magnetizing machine for producing permanent magnets of desired magnetization pattern by use of feedback control. This will in theory mean that an ideal magnetization pattern can be realized, what could be described as a perfect magnet. The machine is to be used for applications requiring high accuracy magnets in terms of the shape of the magnetized area. This is, for example, important for reducing cogging in electrical motors. Results of initial experiments involving use of the machine are presented. The functionality of the machine from a production standpoint and modifications of it that could be useful for mass production purposes, the properties of materials used for magnets, processes involved in manufacturing workpieces that are to be magnetized are discussed. Applications that can benefit from use of a machine of this type are compared with more traditional solutions.
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| 8. |
- Gustafsson, Stefan, et al.
(författare)
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Electromagnetic dispersion modeling and measurements for HVDC power cables
- 2014
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Ingår i: IEEE Transactions on Power Delivery. - : IEEE Press. - 0885-8977 .- 1937-4208. ; 29:6, s. 2439-2447
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a general framework for electromagnetic (EM) modeling, sensitivity analysis, computation, and measurements regarding the wave propagation characteristics of high-voltage direct-current (HVDC) power cables. The modeling is motivated by the potential use with transient analysis, partial-discharge measurements, fault localization and monitoring, and is focused on very long (10 km or more) HVDC power cables with transients propagating in the low-frequency regime of about 0-100 kHz. An exact dispersion relation is formulated together with a discussion on practical aspects regarding the computation of the propagation constant. Experimental time-domain measurement data from an 80-km-long HVDC power cable are used to validate the electromagnetic model, and a mismatch calibration procedure is devised to account for the connection between the measurement equipment and the cable. Quantitative sensitivity analysis is devised to study the impact of parameter uncertainty on wave propagation characteristics. The sensitivity analysis can be used to study how material choices affect the propagation characteristics, and to indicate which material parameters need to be identified accurately in order to achieve accurate fault localization. The analysis shows that the sensitivity of the propagation constant due to a change in the conductivity in the three metallic layers (the inner conductor, the intermediate lead shield, and the outer steel armor) is comparable to the sensitivity with respect to the permittivity of the insulating layer. Hence, proper modeling of the EM fields inside the metallic layers is crucial in the low-frequency regime of 0-100 kHz.
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| 9. |
- Karlberg, Magnus, et al.
(författare)
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Dynamics of rotor systems with clearance and weak pedestals in full contact
- 2010
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Ingår i: 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery 2010 (ISROMAC-13). - Red Hook, NY : Curran Associates, Inc.. - 9781617388484 ; , s. 531-536
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Konferensbidrag (refereegranskat)abstract
- Many rotating machineries are supported by bearings with clearance, which are further clamped in, compared to the bearing stiffness, weak pedestals. As have been reported in several studies, it is essential to choose a proper clearance in order to avoid unwanted vibrations. When rotating machineries supported by bearings with clearance are subjected to stationary loads (gravity, magnetic pull etc.), it may not loose contact between the shaft and the bearing (i.e. full contact). However, even in full contact unwanted dynamics can occur which is of interest in this paper. It is found that the clearance give raise to anisotropic pedestal stiffness. It is further shown that some of the resonance frequencies decrease with the clearance.
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| 10. |
- Karlsson, Christina, et al.
(författare)
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Effects of long-term storage on the detection of proteins, DNA, and mRNA in tissue microarray slides
- 2011
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Ingår i: Journal of Histochemistry and Cytochemistry. - : Sage Publications. - 0022-1554 .- 1551-5044. ; 59:12, s. 1113-1121
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Tidskriftsartikel (refereegranskat)abstract
- Storage of tissue slides has been claimed to induce dramatically reduced antigen detection particularly for immunohistochemistry (IHC). With tissue microarrays, the necessity to serially cut blocks in order to obtain as much material as possible is obvious. The presumed adverse effect of storage might hamper such an approach. The authors designed an experimental setting consisting of four different storage conditions with storage time of tissue slides of up to 1 year. Detection of proteins, DNA, and mRNA was performed using IHC and in situ hybridization techniques. Slight but significant changes in IHC occurred over time. The most important factor is the primary antibody used: four showed no significant changes, whereas limited decreases in 8 antibodies could be detected by image analysis. Whether the antigen was nuclear or cytoplasmic/membranous did not matter. No major differences between different storage conditions could be shown, but storage at 4C was overall the best procedure. Furthermore, gene copy number aberrations, chromosomal translocations, and the presence of mRNA could be detected on slides stored up to 1 year. In conclusion, in tissues optimally formalin fixed and using modern histological techniques, only minute changes in tissue antigenicity are induced by long-term storage.
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