| 1. |
- Capdevila, S., et al.
(författare)
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RFID based probes for EM-field measurements
- 2009
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Ingår i: European Conference on Antennas and Propagation, EuCAP 2009, Proceedings. - : IEEE. - 9783000245732 ; , s. 2787-2790
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Konferensbidrag (refereegranskat)abstract
- In this paper the use of RFID for EM field measurement is studied. A novel RFID antenna with high tuning capabilities is presented and measured, and it is used in combination with several RFID IC to measure the EM field along the H-plane of a horn antenna. A calibration procedure for the non-linear effects in RFID IC is introduced and used to correct the measured fields.
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| 2. |
- Couch, Fergus J., et al.
(författare)
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AURKA F31I polymorphism and breast cancer risk in BRCA1 and BRCA2 mutation carriers: A consortium of investigators of modifiers of BRCA1/2 study
- 2007
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 16:7, s. 1416-1421
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Tidskriftsartikel (refereegranskat)abstract
- The AURKA oncogene is associated with abnormal chromosome segregation and aneuploidy and predisposition to cancer. Amplification of AURKA has been detected at higher frequency in tumors from BRCA1 and BRCA2 mutation carriers than in sporadic breast tumors, suggesting that overexpression of AURKA and inactivation of BRCA1 and BRCA2 cooperate during tumor development and progression. The F31I polymorphism in AURKA has been associated with breast cancer risk in the homozygous state in prior studies. We evaluated whether the AURKA F31I polymorphism modifies breast cancer risk in BRCA1 and BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2. Consortium of Investigators of Modifiers of BRCA1/2 was established to provide sufficient statistical power through increased numbers of mutation carriers to identify polymorphisms that act as modifiers of cancer risk and can refine breast cancer risk estimates in BRCA1 and BRCA2 mutation carriers. A total of 4,935 BRCA1 and 2,241 BRCA2 mutation carriers and 11 individuals carrying both BRCA1 and BRCA2 mutations was genotyped for F31I. Overall, homozygosity for the 311 allele was not significantly associated with breast cancer risk in BRCA1 and BRCA2 carriers combined [hazard ratio (HR), 0.91; 95% confidence interval (95% CI), 0.77-1.061. Similarly, no significant association was seen in BRCA1 (HR, 0.90; 95% Cl, 0.75-1.08) or BRCA2 carriers (HR, 0.93; 95% CI, 0.67-1.29) or when assessing the modifying effects of either bilateral prophylactic oophorectomy or menopausal status of BRCA1 and BRCA2 carriers. In summary, the F31I polymorphism in AURKA is not associated with a modified risk of breast cancer in BRCA1 and BRCA2 carriers.
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| 3. |
- Aibinu, A.M., et al.
(författare)
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A New Method of Correcting Uneven Illumination Problem in Fundus Images
- 2007
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Konferensbidrag (refereegranskat)abstract
- Recent advancements in signal and image processing have reduced the time of diagnoses, effort and pressure on the screeners by providing auto diagnostic tools for different diseases. The success rate of these tools greatly depend on the quality of acquired images. Bad image quality can significantly reduce the specificity and the sensitivity which in turn forces screeners back to their tedious job of manual diagnoses. In acquired fundus images, some areas appear to be brighter than the other, that is areas close to the center of the image are always well illuminated, hence appear very bright while areas far from the center are poorly illuminated hence appears to be very dark. Several techniques including the simple thresholding, Naka Rushton (NR) filtering technique and histogram equalization (HE) method have been suggested by various researchers to overcome this problem. However, each of these methods has limitations at their own and hence the need to develop a more robust technique that will provide better performance with greater flexibility. A new method of compensating uneven (irregular) illumination in fundus images termed global-local adaptive histogram equalization using partially-overlapped windows (GLAPOW) is proposed in this paper. The developed algorithm has been tested and the results obtained show superior performance when compared to other known techniques for uneven illumination correction.
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| 4. |
- Aibinu, A.M., et al.
(författare)
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Automatic Diagnosis of Diabetic Retinopathy from Fundus Images Using Digital Signal and Image Processing Techniques
- 2007
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Konferensbidrag (refereegranskat)abstract
- Automatic diagnosis and display of diabetic retinopathy from images of retina using the techniques of digital signal and image processing is presented in this paper. The acquired images undergo pre-processing to equalize uneven illumination associated with the acquired fundus images. This stage also removes noise present in the image. Segmentation stage clusters the image into two distinct classes while the abnormalities detection stage was used to distinguish between candidate lesions and other information. Methods of diagnosis of red spots, bleeding and detection of vein-artery crossover points have also been developed in this work using the color information, shape, size, object length to breadth ration as contained in the acquired digital fundus image. Furthermore, two graphical user interfaces (GUIs) have also been developed during this work; the first is for the collection of lesion data information and was used by the ophthalmologist in marking images for database while the second GUI is for automatic diagnosing and displaying of the result in a user friendly manner. The algorithm was tested with a separate set of 25 fundus images. From this, the result obtained for microaneurysms and haemorrhages diagnosis shows the appropriateness of the method.
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| 5. |
- Ali, Muhammad, et al.
(författare)
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Effect of wake consideration on estimated costs of wind energy curtailments
- 2009
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Ingår i: 8th International Workshop on Large Scale Integration of Wind Power into Power Systems as well as on Transmission Networks of Offshore Wind Farms, 14-15 Oct. 2009 Bremen.
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Konferensbidrag (refereegranskat)abstract
- Measures such as energy curtailment or gridreinforcement are required to integrate the upcoming windgeneration in parts of the power system with existing transmissionbottlenecks. In order to choose between these two measurespotential wind energy curtailments and its costs need to becarefully evaluated. The paper analyzes the effect of wakeconsideration on the overall energy curtailment cost. For thispurpose detailed wake model was used taking into account partialand multiple shading of wind turbines. It is shown that not onlywind speed but also wind direction of the incoming wind affects theamount of energy produced by a wind farm. A comparison ofcurtailment cost with cost for grid reinforcement in areas withlimited transmission capacity was carried out with and withoutconsideration of wake effect. The effect on curtailment cost due toavailability of wind turbines is also investigated both with andwithout wake effect consideration. The results have proven thatwith consideration of wake effect and availability potential windenergy curtailments are reduced and hence curtailment costs arelowered, making curtailment a cheaper option than gridreinforcement. The method illustrated in the paper can be used inpre-feasibility study to compare the costs of wind curtailment withthe costs of grid reinforcement in order to make sound economicdecision. The method can also be applied in wind farm energy yield estimation.
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| 6. |
- Arko-Mensah, John, et al.
(författare)
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Resistance to mycobacterial infection : a pattern of early immune responses leads to a better control of pulmonary infection in C57BL/6 compared with BALB/c mice.
- 2009
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Ingår i: Vaccine. - : Elsevier BV. - 0264-410X .- 1873-2518. ; 27:52, s. 7418-27
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have compared the immunological responses associated with early pulmonary mycobacterial infection in two mouse strains, BALB/c and C57BL/6 known to exhibit distinct differences in susceptibility to infection with several pathogens. We infected mice via the intranasal route. We have demonstrated that BALB/c was less able to control mycobacterial growth in the lungs during the early phase of pulmonary infection. Our results showed that during the early phase (day 3 to week 1), BALB/c mice exhibited a delay in the production of TNF and IFN-gamma in the lungs compared to C57BL/6 mice. Levels of IL-12 and soluble TNF receptors (sTNFR) were comparable between the mouse strains. The cellular subset distribution in these mice before and after infection showed a higher increase in CD11b+ cells in the lungs of C57BL/6, compared to BALB/c as early as day 3 postinfection. At early time points, higher levels of monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory protein 1 (MIP)-alpha were detected in C57BL/6 than BALB/c mice. In vitro, BCG-infected bone marrow derived macrophages (BMM) from both mouse strains displayed similar capacities to either phagocytose bacteria or produce soluble mediators such as TNF, IL-12 and nitric oxide (NO). Although IFN-gamma stimulation of infected BMM in both mouse strains resulted in the induction of antimycobacterial activity, BALB/c mice had a reduced capacity to kill ingested bacteria. The above observations indicate that the chain of early, possibly innate immunological events occurring during pulmonary mycobacterial infection may directly impact on increased susceptibility or resistance to infection.
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| 7. |
- Babar, Muhammad Ali, et al.
(författare)
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On the Importance of Sound Architectural Practices in the Use of OSS in Software Product Lines
- 2007
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Ingår i: Proceedings of the 2nd International Workshop on Open Source Software and Product Lines (OSSPL 2007), collocated with the 11th International Software Product Line Conference (SPLC 2007), Kyoto, Japan, September 10-14, 2007. - : Cosi. ; , s. 25-32
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Konferensbidrag (refereegranskat)abstract
- Software Product Line (SPL) and Open Source Software (OSS) haveemerged as successful modes of developing software. Although they appear todiffer in terms of development principles and processes, researchers andpractitioners have been increasingly emphasising the need to achieve synergiesby exploiting the ever growing repositories of OSS components for developingSPLs. While there have been calls for the SPL community to accelerate thewidespread use of OSS in SPL, less attention has been paid to how OSScommunities could increase the use of OSS components in SPL. Sincearchitectural issues are considered critical in the SPL community, we proposethat an increased attention on architectural aspects of OSS components mayprovide the confidence that organizations need in order for them to choose anduse OSS components in SPL. We identify a number of architectural practiceswhich are followed by the SPL community and discuss the possibilities for andpotential benefits of incorporating those practices in OSS developmentprocesses.
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| 8. |
- Bari, Muhammad R., et al.
(författare)
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H2O2-induced Ca2+ influx and its inhibition by N-(p-amylcinnamoyl) anthranilic acid in the beta-cells : involvement of TRPM2 channels
- 2009
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Ingår i: Journal of Cellular and Molecular Medicine. - : Wiley. - 1582-1838 .- 1582-4934. ; 13:9B, s. 3260-3267
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 melastatin-related transient receptor potential channel (TRPM2), a member of the melastatin-related TRP (transient receptor potential) subfamily is a Ca(2+)-permeable channel activated by hydrogen peroxide (H(2)O(2)). We have investigated the role of TRPM2 channels in mediating the H(2)O(2)-induced increase in the cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) in insulin-secreting cells. In fura-2 loaded INS-1E cells, a widely used model of beta-cells, and in human beta-cells, H(2)O(2) increased [Ca(2+)](i), in the presence of 3 mM glucose, by inducing Ca(2+) influx across the plasma membrane. H(2)O(2)-induced Ca(2+) influx was not blocked by nimodipine, a blocker of the L-type voltage-gated Ca(2+) channels nor by 2-aminoethoxydiphenyl borate, a blocker of several TRP channels and store-operated channels, but it was completely blocked by N-(p-amylcinnamoyl)anthranilic acid (ACA), a potent inhibitor of TRPM2. Adenosine diphosphate phosphate ribose, a specific activator of TRPM2 channel and H(2)O(2), induced inward cation currents that were blocked by ACA. Western blot using antibodies directed to the epitopes on the N-terminal and on the C-terminal parts of TRPM2 identified the full length TRPM2 (TRPM2-L), and the C-terminally truncated TRPM2 (TRPM2-S) in human islets. We conclude that functional TRPM2 channels mediate H(2)O(2)-induced Ca(2+) entry in beta-cells, a process potently inhibited by ACA.
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| 9. |
- Fletcher, Olivia, et al.
(författare)
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Family history, genetic testing, and clinical risk prediction : pooled analysis of CHEK2 1100delC in 1,828 bilateral breast cancers and 7,030 controls
- 2009
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Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - 1055-9965 .- 1538-7755. ; 18:1, s. 230-4
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Tidskriftsartikel (refereegranskat)abstract
- If breast cancers arise independently in each breast the odds ratio (OR) for bilateral breast cancer for carriers of CHEK2 1100delC should be approximately 5.5, the square of the reported OR for a first primary (OR, 2.34). In the subset of bilateral cases with one or more affected relatives, the predicted carrier OR should be approximately 9. We have tested these predictions in a pooled set of 1,828 cases with 2 primaries and 7,030 controls from 8 studies. The second primary OR for CHEK2 1100delC carriers was 6.43 (95% confidence interval, 4.33-9.56; P < 0.0001), significantly greater than the published estimate for a first primary (P < 0.001) but consistent with its square. The predicted increase in carrier OR with increasing numbers of affected relatives was seen using bilateral cases from the UK (P(trend) = 0.0003) and Finland (P(trend) = 0.37), although not using those from the Netherlands and Russia (P = 0.001 for heterogeneity between countries). Based on a standard genetic model, we predict lifetime risks for CHEK2 1100delC carrier and noncarrier daughters of bilateral breast cancer cases of 37% and 18%, respectively. Our results imply that clinical management of the daughter of a woman with bilateral breast cancer should depend on her CHEK2 1100delC carrier status. This and other moderate penetrance breast cancer susceptibility alleles, together with family history data, will thus identify increasing numbers of women at potentially very high risk. Before such predictions are accepted by clinical geneticists, however, further population-based evidence is needed on the effect of CHEK2 1100delC and other moderate penetrance alleles in women with a family history of breast cancer.
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| 10. |
- Iqbal, Muhammad Imran, et al.
(författare)
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Detection of Vascular Intersection in Retina Fundus Image Using Modified Cross Point Number and Neural Network Technique
- 2008
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Konferensbidrag (refereegranskat)abstract
- Vascular intersection can be used as one of the symptoms for monitoring and diagnosis of diabetic retinopathy from fundus images. In this work we apply the knowledge of digital image processing, fuzzy logic and neural network technique to detect bifurcation and vein-artery cross-over points in fundus images. The acquired images undergo preprocessing stage for illumination equalization and noise removal. Segmentation stage clusters the image into two distinct classes by the use of fuzzy c-means technique, neural network technique and modified cross-point number (MCN) methods were employed for the detection of bifurcation and cross-over points. MCN uses a 5x5 window with 16 neighboring pixels for efficient detection of bifurcation and cross over points in fundus images. Result obtained from applying this hybrid method on both real and simulated vascular points shows that this method perform better than the existing simple cross-point number (SCN) method, thus an improvement to the vascular point detection and a good tool in the monitoring and diagnosis of diabetic retinopathy. ©2008 IEEE.
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| 11. |
- Muhammad, Riaz, et al.
(författare)
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Experimental and finite element method calculation of piezoelectric power generation from ZnO nanowire arrays grown on different substrates using high and low temperature methods
- 2008
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we investigate the piezoelectric power generation from ZnO nanowire arrays grown using different methods. The ZnO nanowires are grown on n-SiC and n-Si substrates using both the high-temperature vapor liquid solid (VLS) and the lowtemperature aqueous chemical growth (ACG) methods. A conductive atomic force microscope (AFM) is used in contact mode to deflect the ZnO nanowire arrays. A piezoelectric potential across the nanowires is produced and then released via the rectifying behavior of the Schottky barrier at the platinum metal-ZnO interface. We do not observe any substrate effect but the growth method, crystal quality, density, length and diameter (aspect ratio) of the nanowires are found to affect the piezoelectric behavior. These parameters can significantly affect the performance manifested in the observed output voltage signal. Based on these parameters, we compare four nanogenerators under identical conditions. During the AFM scanning in contact mode without biased voltage, the ZnO nanowire arrays grown by the VLS method produce higher and larger output voltage signal of 35 mV compared to ZnO nanowires arrays grown by the ACG method, which produce smaller output voltage signal of 5 mV. We apply finite element (FE) method calculations to investigate the output voltage of ZnO nanowires based nanogenerators with different aspects ratios. From FE results we find that the output voltage of the nanogenerator is decreased above an aspect ratio 80 of ZnO nanowires.
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| 12. |
- Nawrot, Tim S, et al.
(författare)
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Oxidative properties of ambient PM2.5 and elemental composition : heterogeneous associations in 19 European cities
- 2009
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:30, s. 4595-4602
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Tidskriftsartikel (refereegranskat)abstract
- We assessed the extent to which constituents of PM2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium.
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| 13. |
- Ullah, Muhammad Muneeb, et al.
(författare)
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Towards Robust Place Recognition for Robot Localization
- 2008
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Ingår i: 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9. ; , s. 530-537
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Konferensbidrag (refereegranskat)abstract
- Localization and context interpretation are two key competences for mobile robot systems. Visual place recognition, as opposed to purely geometrical models, holds promise of higher flexibility and association of semantics to the model. Ideally, a place recognition algorithm should be robust to dynamic changes and it should perform consistently when recognizing a room (for instance a corridor) in different geographical locations. Also, it should be able to categorize places, a crucial capability for transfer of knowledge and continuous learning. In order to test the suitability of visual recognition algorithms for these tasks, this paper presents a new database, acquired in three different labs across Europe. It contains image sequences of several rooms under dynamic changes, acquired at the same time with a perspective and omnidirectional camera, mounted on a socket. We assess this new database with an appearance based algorithm that combines local features with support vector machines through an ad-hoc kernel. Results show the effectiveness of the approach and the value of the database.
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