| 1. |
- Abelev, B., et al.
(författare)
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Technical Design Report for the Upgrade of the ALICE Inner Tracking System
- 2014
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 41:8
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Tidskriftsartikel (refereegranskat)abstract
- LICE (A Large Ion Collider Experiment) is studying the physics of strongly interacting matter, and in particular the properties of the Quark–Gluon Plasma (QGP), using proton–proton, proton–nucleus and nucleus–nucleus collisions at the CERN LHC (Large Hadron Collider). The ALICE Collaboration is preparing a major upgrade of the experimental apparatus, planned for installation in the second long LHC shutdown in the years 2018–2019. A key element of the ALICE upgrade is the construction of a new, ultra-light, high-resolution Inner Tracking System (ITS) based on monolithic CMOS pixel detectors. The primary focus of the ITS upgrade is on improving the performance for detection of heavy-flavour hadrons, and of thermal photons and low-mass di-electrons emitted by the QGP. With respect to the current detector, the new Inner Tracking System will significantly enhance the determination of the distance of closest approach to the primary vertex, the tracking efficiency at low transverse momenta, and the read-out rate capabilities. This will be obtained by seven concentric detector layers based on a 50 μm thick CMOS pixel sensor with a pixel pitch of about 30×30 μm2. This document, submitted to the LHCC (LHC experiments Committee) in September 2013, presents the design goals, a summary of the R&D activities, with focus on the technical implementation of the main detector components, and the projected detector and physics performance.
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| 2. |
- Maxwell, Christopher A., et al.
(författare)
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Interplay between BRCA1 and RHAMM Regulates Epithelial Apicobasal Polarization and May Influence Risk of Breast Cancer
- 2011
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Ingår i: PLoS Biology. - : Public Library of Science (PLoS). - 1545-7885 .- 1544-9173. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Differentiated mammary epithelium shows apicobasal polarity, and loss of tissue organization is an early hallmark of breast carcinogenesis. In BRCA1 mutation carriers, accumulation of stem and progenitor cells in normal breast tissue and increased risk of developing tumors of basal-like type suggest that BRCA1 regulates stem/progenitor cell proliferation and differentiation. However, the function of BRCA1 in this process and its link to carcinogenesis remain unknown. Here we depict a molecular mechanism involving BRCA1 and RHAMM that regulates apicobasal polarity and, when perturbed, may increase risk of breast cancer. Starting from complementary genetic analyses across families and populations, we identified common genetic variation at the low-penetrance susceptibility HMMR locus (encoding for RHAMM) that modifies breast cancer risk among BRCA1, but probably not BRCA2, mutation carriers: n = 7,584, weighted hazard ratio ((w)HR) = 1.09 (95% CI 1.02-1.16), p(trend) = 0.017; and n = 3,965, (w)HR = 1.04 (95% CI 0.94-1.16), p(trend) = 0.43; respectively. Subsequently, studies of MCF10A apicobasal polarization revealed a central role for BRCA1 and RHAMM, together with AURKA and TPX2, in essential reorganization of microtubules. Mechanistically, reorganization is facilitated by BRCA1 and impaired by AURKA, which is regulated by negative feedback involving RHAMM and TPX2. Taken together, our data provide fundamental insight into apicobasal polarization through BRCA1 function, which may explain the expanded cell subsets and characteristic tumor type accompanying BRCA1 mutation, while also linking this process to sporadic breast cancer through perturbation of HMMR/RHAMM.
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| 3. |
- Qi, Qibin, et al.
(författare)
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FTO genetic variants, dietary intake and body mass index : insights from 177 330 individuals
- 2014
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:25, s. 6961-6972
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Tidskriftsartikel (refereegranskat)abstract
- FTO is the strongest known genetic susceptibility locus for obesity. Experimental studies in animals suggest the potential roles of FTO in regulating food intake. The interactive relation among FTO variants, dietary intake and body mass index (BMI) is complex and results from previous often small-scale studies in humans are highly inconsistent. We performed large-scale analyses based on data from 177 330 adults (154 439 Whites, 5776 African Americans and 17 115 Asians) from 40 studies to examine: (i) the association between the FTO-rs9939609 variant (or a proxy single-nucleotide polymorphism) and total energy and macronutrient intake and (ii) the interaction between the FTO variant and dietary intake on BMI. The minor allele (A-allele) of the FTO-rs9939609 variant was associated with higher BMI in Whites (effect per allele = 0.34 [0.31, 0.37] kg/m(2), P = 1.9 × 10(-105)), and all participants (0.30 [0.30, 0.35] kg/m(2), P = 3.6 × 10(-107)). The BMI-increasing allele of the FTO variant showed a significant association with higher dietary protein intake (effect per allele = 0.08 [0.06, 0.10] %, P = 2.4 × 10(-16)), and relative weak associations with lower total energy intake (-6.4 [-10.1, -2.6] kcal/day, P = 0.001) and lower dietary carbohydrate intake (-0.07 [-0.11, -0.02] %, P = 0.004). The associations with protein (P = 7.5 × 10(-9)) and total energy (P = 0.002) were attenuated but remained significant after adjustment for BMI. We did not find significant interactions between the FTO variant and dietary intake of total energy, protein, carbohydrate or fat on BMI. Our findings suggest a positive association between the BMI-increasing allele of FTO variant and higher dietary protein intake and offer insight into potential link between FTO, dietary protein intake and adiposity.
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| 4. |
- Ellinor, Patrick T., et al.
(författare)
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Meta-analysis identifies six new susceptibility loci for atrial fibrillation
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 44:6, s. 88-670
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Tidskriftsartikel (refereegranskat)abstract
- Atrial fibrillation is a highly prevalent arrhythmia and a major risk factor for stroke, heart failure and death(1). We conducted a genome-wide association study (GWAS) in individuals of European ancestry, including 6,707 with and 52,426 without atrial fibrillation. Six new atrial fibrillation susceptibility loci were identified and replicated in an additional sample of individuals of European ancestry, including 5,381 subjects with and 10,030 subjects without atrial fibrillation (P < 5 x 10(-8)). Four of the loci identified in Europeans were further replicated in silico in a GWAS of Japanese individuals, including 843 individuals with and 3,350 individuals without atrial fibrillation. The identified loci implicate candidate genes that encode transcription factors related to cardiopulmonary development, cardiac-expressed ion channels and cell signaling molecules.
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| 5. |
- Peden, John F., et al.
(författare)
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A genome-wide association study in Europeans and South Asians identifies five new loci for coronary artery disease
- 2011
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 43:4, s. 339-344
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have identified 11 common variants convincingly associated with coronary artery disease (CAD)(1-7), a modest number considering the apparent heritability of CAD(8). All of these variants have been discovered in European populations. We report a meta-analysis of four large genome-wide association studies of CAD, with similar to 575,000 genotyped SNPs in a discovery dataset comprising 15,420 individuals with CAD (cases) (8,424 Europeans and 6,996 South Asians) and 15,062 controls. There was little evidence for ancestry-specific associations, supporting the use of combined analyses. Replication in an independent sample of 21,408 cases and 19,185 controls identified five loci newly associated with CAD (P < 5 x 10(-8) in the combined discovery and replication analysis): LIPA on 10q23, PDGFD on 11q22, ADAMTS7-MORF4L1 on 15q25, a gene rich locus on 7q22 and KIAA1462 on 10p11. The CAD-associated SNP in the PDGFD locus showed tissue-specific cis expression quantitative trait locus effects. These findings implicate new pathways for CAD susceptibility.
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| 6. |
- Vasile, Massimiliano, et al.
(författare)
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The Suaineadh Project : a Stepping Stone Towards the Deployment of Large Flexible Structures in Space
- 2010
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Ingår i: Proceedings of the 61<sup>st</sup> International Astronautical Congress. - : the International Astronautical Federation. ; , s. IAC-10-C3.4-
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Konferensbidrag (refereegranskat)abstract
- The Suaineadh project aims at testing the controlled deployment and stabilization of space web. The deployment system is based on a simple yet ingenious control of the centrifugal force that will pull each of the four daughters sections apart. The four daughters are attached onto the four corners of a square web, and will be released from their initial stowed configuration attached to a central hub. Enclosed in the central hub is a specifically designed spinning reaction wheel that controls the rotational speed with a closed loop control fed by measurements from an onboard inertial measurement sensor. Five other such sensors located within the web and central hub provide information on the surface curvature of the web, and progression of the deployment. Suaineadh is currently at an advanced stage of development: all the components are manufactured with the subsystems integrated and are presently awaiting full integration and testing. This paper will present the current status of the Suaineadh project and the results of the most recent set of tests. In particular, the paper will cover the overall mechanical design of the system, the electrical and sensor assemblies, the communication and power systems and the spinning wheel with its control system.
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| 7. |
- Arof, A. K., et al.
(författare)
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Quasi solid state dye-sensitized solar cells based on polyvinyl alcohol (PVA) electrolytes containing redox couple
- 2014
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Ingår i: Optical and Quantum Electronics. - : Springer Science and Business Media LLC. - 0306-8919 .- 1572-817X. ; 46:1, s. 143-154
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Tidskriftsartikel (refereegranskat)abstract
- Quasi solid state dye-sensitized solar cells (DSSCs) have been fabricated with electrolytes containing I-/I-3(-) redox couple using 80% hydrolyzed polyvinyl alcohol (PVA) doped with potassium iodide (KI) and a mixture of potassium iodide and tetrapropyl ammonium iodide (Pr4NI) salts. The quasi solid state gel polymer electrolytes were prepared using 1: 1 ethylene carbonate (EC): propylene carbonate (PC) mixture. The solar cells have the structure of ITO/TiO2/N-3-Dye/electrolyte/Pt/ITO. The conductivity of the electrolytes has been calculated from the bulk resistance value determined using the electrochemical impedance spectroscopy. The performance of the DSSCs has been studied by varying the concentration of the doping salts in the electrolyte and incident light intensity. The DSSC fabricated with the KI salt electrolyte containing 9.9 wt% PVA, 39.6 wt% EC, 39.6 wt% PC, 10.9 wt% KI(+I-2) exhibited the best power conversion efficiency of 1.97 %. However, the DSSC with a double-salt electrolyte containing 9.9 wt% PVA: 39.6 wt% EC: 39.6 wt% PC: (6.5 wt% KI: 4.4 wt% Pr4NI) (+I-2) exhibited a higher efficiency of 3.27% under 100 mW/cm(2) light intensity. The efficiency of this cell increased to 4.59 % under dimmer light of intensity of 54 mW/cm(2).
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| 8. |
- Aibinu, A.M., et al.
(författare)
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Vascular intersection detection in retina fundus images using a new hybrid approach
- 2010
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Ingår i: Computers in Biology and Medicine. - : Elsevier. - 0010-4825 .- 1879-0534. ; 40:1, s. 81-89
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Tidskriftsartikel (refereegranskat)abstract
- The use of vascular intersection aberration as one of the signs when monitoring and diagnosing diabetic retinopathy from retina fundus images (FIs) has been widely reported in the literature. In this paper, a new hybrid approach called the combined cross-point number (CCN) method able to detect the vascular bifurcation and intersection points in FIs is proposed. The CCN method makes use of two vascular intersection detection techniques, namely the modified cross-point number (MCN) method and the simple cross-point number (SCN) method. Our proposed approach was tested on images obtained from two different and publicly available fundus image databases. The results show a very high precision, accuracy, sensitivity and low false rate in detecting both bifurcation and crossover points compared with both the MCN and the SCN methods.
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| 9. |
- Ala-Laurinaho, J., et al.
(författare)
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TUMESA - MEMS tuneable metamaterials for smart wireless applications
- 2012
-
Ingår i: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012. - : IEEE. - 9782874870286 ; , s. 95-98
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Konferensbidrag (refereegranskat)abstract
- This paper describes the main results of the EU FP7 project TUMESA - MEMS tuneable metamaterials for smart wireless applications. In this project, we studied several reconfigurable antenna approaches that combine the new technology of MEMS with the new concept of artificial electromagnetic materials and surfaces (metamaterials and metasurfaces) for realisation of millimetre wave phase shifters and beam-steering devices. MEMS technology allows to miniaturise electronic components, reduce their cost in batch production, and effectively compete with semiconductor and ferroelectric based technologies in terms of losses at millimetre wavelengths. Novel tuneable materials and components proposed in this project perform as smart beam steering devices. Fabricated with MEMS technology in batch and on a single chip, proposed tuneable devices allow substituting of larger and more complex sub-system of, e.g., a radar sensor. This substitution provides a dramatic cost reduction on a system level.
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| 10. |
- Ali, A., et al.
(författare)
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Potentiometric urea biosensor utilizing nanobiocomposite of chitosan-iron oxide magnetic nanoparticles
- 2013
-
Ingår i: 21st International Laser Physics Workshop 23–27 July 2012, Calgary, Canada. - : Institute of Physics (IOP).
-
Konferensbidrag (refereegranskat)abstract
- The iron oxide (Fe3O4) magnetic nanoparticles have been fabricated through a simple, cheap and reproducible approach. Scanning electron microscope, x-rays powder diffraction of the fabricated nanoparticles. Furthermore, the fabrication of potentiometric urea biosensor is carried out through drop casting the initially prepared isopropanol and chitosan solution, containing Fe3O4 nanoparticles, on the glass fiber filter with a diameter of 2 cm and a copper wire (of thickness −500 μm) has been utilized to extract the voltage signal from the functionalized nanoparticles. The functionalization of surface of the Fe3O4 nanoparticles is obtained by the electrostatically immobilization of urease onto the nanobiocomposite of the chitosan- Fe3O4 in order to enhance the sensitivity, specificity, stability and reusability of urea biosensor. Electrochemical detection procedure has been adopted to measure the potentiometric response over the wide logarithmic concentration range of the 0.1 mM to 80 mM. The Fe3O4 nanoparticles based urea biosensor depicts good sensitivity with ~42 mV per decade at room temperature. Durability of the biosensor could be considerably enhanced by applying a thin layer of the nafion. In addition, the reasonably stable output response of the biosensor has been found to be around 12 sec.
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| 11. |
- Almas, Muhammad Shoaib, et al.
(författare)
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Open Source SCADA Implementation and PMU Integration for Power System Monitoring and Control Applications
- 2014
-
Ingår i: PES General Meeting | Conference & Exposition, 2014 IEEE. - : IEEE conference proceedings. ; , s. -5
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the implementation of an Open Source SCADA system in a laboratory and discusses methods for PMU data integration into SCADA. SCADA BR is a web-browser based SCADA that enables the user to access monitoring, control and automation equipment over multiple protocols. For implementation, protection relays from SEL are configured as DNP3 outstations to act as slaves and SCADA BR which is installed in one of the workstations in the laboratory acts as master. The evaluation of SCADA BR has been performed by executing a power system model in a real-time simulator and coupling its analog outputs with the protection relays. The integration of PMU measurements in the SCADA system and their use for monitoring is discussed. The limitations of the SCADA systems to fully utilize PMU data are also presented.
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| 12. |
- Almas, Muhammad Shoaib, et al.
(författare)
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Synchrophasor Network, Laboratory and Software Applications Developed in the STRONg2rid Project
- 2014
-
Ingår i: PES General Meeting Conference & Exposition, 2014 IEEE. - : IEEE conference proceedings. ; , s. 1-5
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the activities carried out in one of the work packages of the Nordic Energy Research funded project Smart Transmission Grid Operation and Control (STRONg2rid). The main objective of the work package is to deploy a state-of-the-art software and hardware for developing power system operation, protection, control and automation applications. Several PMUs have been deployed at partner universities and a network of synchrophasors has been set up. In addition the Smart Transmission System Laboratory (SmarTS-Lab) has been established. This laboratory serves as a test-bench to develop and verify smart transmission grid technologies. A software development kit (S3DK) was developed within the project. The S3DK has been used to implement PMU-based applications and deploy them in different targets, including smart phones and tablets. Several tools and software applications which utilize synchrophasor measurements (from the laboratory or the deployed university PMU network) to perform power system monitoring, sub-synchronous power oscillation detection, etc., have been developed and are presented herein.
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| 13. |
- Cairns, Marie-Louise, et al.
(författare)
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The potential of electron beam radiation for simultaneous surface modification and bioresorption control of PLLA.
- 2012
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Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 100:9, s. 2223-9
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Tidskriftsartikel (refereegranskat)abstract
- Bioresorbable polymers have been widely investigated as materials exhibiting significant potential for successful application in the fields of tissue engineering and drug delivery. Further to the ability to control degradation, surface engineering of polymers has been highlighted as a key method central to their development. Previous work has demonstrated the ability of electron beam (e-beam) technology to control the degradation profiles and bioresorption of a number of commercially relevant bioresorbable polymers (poly-l-lactic acid (PLLA), L-lactide/DL-lactide co-polymer (PLDL) and poly(lactic-co-glycolic acid (PLGA)). This work investigates the further potential of e-beam technology to impart added biofunctionality through the manipulation of polymer (PLLA) surface properties. PLLA samples were subjected to e-beam treatments in air, with varying beam energies and doses. Surface characterization was then performed using contact angle analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy. Results demonstrated a significant increase in surface wettability post e-beam treatment. In correlation with this, XPS data showed the introduction of oxygen-containing functional groups to the surface of PLLA. Raman spectroscopy indicated chain scission in the near surface region of PLLA (as predicted). However, e-beam effects on surface properties were not shown to be dependent on beam energy or dose. E-beam irradiation did not seem to affect the surface roughness of PLLA as a direct consequence of the treatment.
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| 14. |
- Chuquimia, Olga D., 1977-, et al.
(författare)
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The Role of Alveolar Epithelial Cells in Initiating and Shaping Pulmonary Immune Responses : Communication between Innate and Adaptive Immune Systems
- 2012
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:2, s. e32125-
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Tidskriftsartikel (refereegranskat)abstract
- Macrophages and dendritic cells have been recognized as key players in the defense against mycobacterial infection. However, more recently, other cells in the lungs such as alveolar epithelial cells (AEC) have been found to play important roles in the defense and pathogenesis of infection. In the present study we first compared AEC with pulmonary macrophages (PuM) isolated from mice in their ability to internalize and control Bacillus Calmette-Guerin (BCG) growth and their capacity as APCs. AEC were able to internalize and control bacterial growth as well as present antigen to primed T cells. Secondly, we compared both cell types in their capacity to secrete cytokines and chemokines upon stimulation with various molecules including mycobacterial products. Activated PuM and AEC displayed different patterns of secretion. Finally, we analyzed the profile of response of AEC to diverse stimuli. AEC responded to both microbial and internal stimuli exemplified by TLR ligands and IFNs, respectively. The response included synthesis by AEC of several factors, known to have various effects in other cells. Interestingly, TNF could stimulate the production of CCL2/MCP-1. Since MCP-1 plays a role in the recruitment of monocytes and macrophages to sites of infection and macrophages are the main producers of TNF, we speculate that both cell types can stimulate each other. Also, another cell-cell interaction was suggested when IFNs (produced mainly by lymphocytes) were able to induce expression of chemokines (IP-10 and RANTES) by AEC involved in the recruitment of circulating lymphocytes to areas of injury, inflammation, or viral infection. In the current paper we confirm previous data on the capacity of AEC regarding internalization of mycobacteria and their role as APC, and extend the knowledge of AEC as a multifunctional cell type by assessing the secretion of a broad array of factors in response to several different types of stimuli.
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| 15. |
- Dabrowski, Michal, et al.
(författare)
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Reliability assessment of null allele detection : inconsistencies between and within different methods
- 2014
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 14:2, s. 361-373
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Tidskriftsartikel (refereegranskat)abstract
- Microsatellite loci are widely used in population genetic studies, but the presence of null alleles may lead to biased results. Here, we assessed five methods that indirectly detect null alleles and found large inconsistencies among them. Our analysis was based on 20 microsatellite loci genotyped in a natural population of Microtus oeconomus sampled during 8years, together with 1200 simulated populations without null alleles, but experiencing bottlenecks of varying duration and intensity, and 120 simulated populations with known null alleles. In the natural population, 29% of positive results were consistent between the methods in pairwise comparisons, and in the simulated data set, this proportion was 14%. The positive results were also inconsistent between different years in the natural population. In the null-allele-free simulated data set, the number of false positives increased with increased bottleneck intensity and duration. We also found a low concordance in null allele detection between the original simulated populations and their 20% random subsets. In the populations simulated to include null alleles, between 22% and 42% of true null alleles remained undetected, which highlighted that detection errors are not restricted to false positives. None of the evaluated methods clearly outperformed the others when both false-positive and false-negative rates were considered. Accepting only the positive results consistent between at least two methods should considerably reduce the false-positive rate, but this approach may increase the false-negative rate. Our study demonstrates the need for novel null allele detection methods that could be reliably applied to natural populations.
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| 16. |
- Danielson, Magnus, et al.
(författare)
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Analysis of Communication Network Challenges for Synchrophasor-Based Wide-Area Applications
- 2013
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Ingår i: Proceedings of IREP Symposium. - : IEEE conference proceedings. - 9781479901999
-
Konferensbidrag (refereegranskat)abstract
- Wide-area synchrophasor applications inherently depend on the underlying IT and communications infrastructure supporting them. In particular, closed loop control systems for power grid oscillation damping is problematic, as it is a complex mixture of power grid monitoring, communication network properties and overall system stability issues. This article offers a holistic analysis of these fields, proposing a combined requirement on the full system: to keep system delays down to maintain stability. Simulation results to support the analysis findings, also showing how observability of power oscillations is important in combination with system delays related to feedback signals, and finally laying out experimentation plans to be performed in the lab on a complex power-grid model with real PMUs, communication network and controllers interacting with the SmarTS Lab real-time hardware-in-the-loop simulator platform.
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Golsteijn, Laura, et al.
(författare)
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Assessing predictive uncertainty in comparative toxicity potentials of triazoles
- 2014
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 33:2, s. 293-301
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Tidskriftsartikel (refereegranskat)abstract
- Comparative toxicity potentials (CTPs) quantify the potential ecotoxicological impacts of chemicals per unit of emission. They are the product of a substance's environmental fate, exposure, and hazardous concentration. When empirical data are lacking, substance properties can be predicted. The goal of the present study was to assess the influence of predictive uncertainty in substance property predictions on the CTPs of triazoles. Physicochemical and toxic properties were predicted with quantitative structure-activity relationships (QSARs), and uncertainty in the predictions was quantified with use of the data underlying the QSARs. Degradation half-lives were based on a probability distribution representing experimental half-lives of triazoles. Uncertainty related to the species' sample size that was present in the prediction of the hazardous aquatic concentration was also included. All parameter uncertainties were treated as probability distributions, and propagated by Monte Carlo simulations. The 90% confidence interval of the CTPs typically spanned nearly 4 orders of magnitude. The CTP uncertainty was mainly determined by uncertainty in soil sorption and soil degradation rates, together with the small number of species sampled. In contrast, uncertainty in species-specific toxicity predictions contributed relatively little. The findings imply that the reliability of CTP predictions for the chemicals studied can be improved particularly by including experimental data for soil sorption and soil degradation, and by developing toxicity QSARs for more species. (c) 2013 SETAC
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| 21. |
- Gram, Magnus, et al.
(författare)
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Increased levels of hemoglobin and alpha1-microglobulin in Huntington's disease.
- 2012
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Ingår i: Frontiers in Bioscience (Elite Edition). - 1945-0508. ; 4, s. 950-957
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Tidskriftsartikel (refereegranskat)abstract
- Hemoglobin released from damaged erythrocytes is a major pro-oxidant, generator of free radicals and inflammatory mediator. Huntington's disease is an inherited neurodegenerative disorder characterized by both neurological and systemic abnormalities, in which oxidative stress has been suggested as a possible pathogenic mechanism. In the present work we have investigated levels of hemoglobin and markers of oxidative damage, including the heme- and radical-scavenger alpha1-microglobulin, in plasma and urine samples from two separate sample cohorts, including controls, premanifest gene carriers and subjects at different stages of Huntington's disease. The results show statistically significant increased levels of hemoglobin and alpha1-microglobulin in Huntington's disease urine samples. Interestingly, urine hemoglobin levels correlate with clinical severity. The results suggest that hemolysis may be linked to the pathogenesis of Huntington's disease and that assay of hemoglobin and alpha1-microglobulin may provide biomarkers that are linked to biologically relevant processes.
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| 22. |
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| 23. |
- Iqbal, Muhammad Sarfraz, et al.
(författare)
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Understanding quantitative structure-property relationships uncertainty in environmental fate modeling
- 2013
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 32:5, s. 1069-1076
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Tidskriftsartikel (refereegranskat)abstract
- In cases in which experimental data on chemical-specific input parameters are lacking, chemical regulations allow the use of alternatives to testing, such as in silico predictions based on quantitative structure–property relationships (QSPRs). Such predictions are often given as point estimates; however, little is known about the extent to which uncertainties associated with QSPR predictions contribute to uncertainty in fate assessments. In the present study, QSPR-induced uncertainty in overall persistence (POV) and long-range transport potential (LRTP) was studied by integrating QSPRs into probabilistic assessments of five polybrominated diphenyl ethers (PBDEs), using the multimedia fate model Simplebox. The uncertainty analysis considered QSPR predictions of the fate input parameters' melting point, water solubility, vapor pressure, organic carbon–water partition coefficient, hydroxyl radical degradation, biodegradation, and photolytic degradation. Uncertainty in POV and LRTP was dominated by the uncertainty in direct photolysis and the biodegradation half-life in water. However, the QSPRs developed specifically for PBDEs had a relatively low contribution to uncertainty. These findings suggest that the reliability of the ranking of PBDEs on the basis of POV and LRTP can be substantially improved by developing better QSPRs to estimate degradation properties. The present study demonstrates the use of uncertainty and sensitivity analyses in nontesting strategies and highlights the need for guidance when compounds fall outside the applicability domain of a QSPR.
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| 24. |
- Kaewmaraya, Thanayut, et al.
(författare)
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Electronic structure and ionic diffusion of green battery cathode material : Mg2Mo6S8
- 2014
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Ingår i: Solid State Ionics. - : Elsevier BV. - 0167-2738 .- 1872-7689. ; 261, s. 17-20
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Tidskriftsartikel (refereegranskat)abstract
- We report ab-initio density functional theory calculations of crystal and electronic structure of Mg2Mo6S8, a candidate material to be used in rechargeable magnesium batteries, by employing hybrid exchange-correlation functionals. We find that Mg2Mo6S8 crystalizes in a triclinic geometry and it is a semiconductor with an indirect band gap. Ab-initio molecular dynamics shows that Mg ions present progressive diffusion starting at 200 K with a preferable path through the channel between Mo6S8 blocks along the [010] direction. The intercalation voltage of the system is also determined and the results show that the voltage evaluated by PBE and hybrid functionals likely implies the lower and the upper limit of the experimental value. Lastly, we confirm the dynamical stability of the crystal structure by the calculated phonon dispersion relation.
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| 25. |
- MacLennan, Steven, et al.
(författare)
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Systematic Review of Oncological Outcomes Following Surgical Management of Localised Renal Cancer
- 2012
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Ingår i: European Urology. - : Elsevier BV. - 0302-2838 .- 1873-7560. ; 61:5, s. 972-993
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Forskningsöversikt (refereegranskat)abstract
- Context: Renal cell carcinoma (RCC) accounts for 2-3% of adult malignancies. There remain uncertainties over the oncological outcomes for the surgical management of localised RCC. Objective: Systematically review relevant literature comparing oncological outcomes of surgical management of localised RCC (T1-2N0M0). Evidence acquisition: Relevant databases including Medline, Embase, and the Cochrane Library were searched up to October 2010, and an updated scoping search was performed up to January 2012. Randomised controlled trials (RCTs) or quasi-RCTs, prospective observational studies with controls, retrospective matched-pair studies, and comparative studies from well-defined registries/databases were included. The main outcomes were overall survival, cancer-specific survival, recurrence, and metastases. The Cochrane risk of bias tool was used to assess RCTs, and an extended version was used to assess nonrandomised studies (NRSs). The quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Evidence synthesis: A total of 4580 abstracts and 389 full-text articles were assessed. Thirty-four studies met the inclusion criteria (6 RCTs and 28 NRSs). Meta-analyses were planned but were deemed inappropriate due to data heterogeneity. There were high risks of bias and low-quality evidence across the evidence base. Open radical nephrectomy and open partial nephrectomy showed similar cancer-specific and overall survival, but when both open and laparoscopic approaches are considered together, the evidence showed improved survival for partial nephrectomy for tumours <= 4 cm. The overall evidence suggests either equivalent or better survival with partial nephrectomy. Laparoscopic radical nephrectomy offered equivalent survival to open radical nephrectomy, and all laparoscopic approaches achieved equivalent survival. Open and laparoscopic partial nephrectomy achieved equivalent survival. The issue of ipsilateral adrenalectomy or complete lymph node dissection with radical nephrectomy or partial nephrectomy remains unresolved. Conclusions: The evidence base suggests localised RCCs are best managed by nephron-sparing surgery where technically feasible. However, the current evidence base has significant limitations due to studies of low methodological quality marked by high risks of bias. (C) 2012 European Association of Urology. Published by Elsevier B. V. All rights reserved.
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| 26. |
- MacLennan, Steven, et al.
(författare)
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Systematic review of perioperative and quality-of-life outcomes following surgical management of localised renal cancer
- 2012
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Ingår i: European Urology. - : Elsevier BV. - 0302-2838 .- 1873-7560. ; 62:6, s. 1097-1117
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Forskningsöversikt (refereegranskat)abstract
- Context: For the treatment of localised renal cell carcinoma (RCC), uncertainties remain over the perioperative and quality-of-life (QoL) outcomes for the many different surgical techniques and approaches of nephrectomy. Controversy also remains on whether newer minimally invasive nephron-sparing interventions offer better QoL and perioperative outcomes, and whether adrenalectomy and lymphadenectomy should be performed simultaneously with nephrectomy. These non-oncological outcomes are important because they may have a considerable impact on localised RCC treatment decision making.Objective: To review systematically all the relevant published literature comparing perioperative and QoL outcomes of surgical management of localised RCC (T1-2N0M0).Evidence acquisition: Relevant databases including Medline, Embase, and the Cochrane Library were searched up to January 2012. Randomised controlled trials (RCTs) or quasi-randomised controlled trials, prospective observational studies with controls, retrospective matched-pair studies, and comparative studies from well-defined registries/databases were included. The outcome measures were QoL, analgesic requirement, length of hospital stay, time to normal activity level, surgical morbidity and complications, ischaemia time, renal function, blood loss, length of operation, need for blood transfusion, and perioperative mortality. The Cochrane risk of bias tool was used to assess RCTs, and an extended version was used to assess nonrandomised studies (NRSs). The quality of evidence was assessed using Grading of Recommendations, Assessment, Development, and Evaluation.Evidence synthesis: A total of 4580 abstracts and 380 full-text articles were assessed, and 29 studies met the inclusion criteria (7 RCTs and 22 NRSs). There were high risks of bias and low-quality evidence for studies meeting the inclusion criteria. There is good evidence indicating that partial nephrectomy results in better preservation of renal function and better QoL outcomes than radical nephrectomy regardless of technique or approach. Regarding radical nephrectomy, the laparoscopic approach has better perioperative outcomes than the open approach, and there is no evidence of a difference between the transperitoneal and retroperitoneal approaches. Alternatives to standard laparoscopic radical nephrectomy (LRN) such as hand-assisted, robot-assisted, or single-port techniques appear to have similar perioperative outcomes. There is no good evidence to suggest that minimally invasive procedures such as cryotherapy or radiofrequency ablation have superior perioperative or QoL outcomes to nephrectomy. Regarding concomitant lymphadenectomy during nephrectomy, there were low event rates for complications, and no definitive difference was observed. There was no evidence to base statements about concomitant ipsilateral adrenalectomy during nephrectomy.Conclusions: Partial nephrectomy results in significantly better preservation of renal function over radical nephrectomy. For tumours where partial nephrectomy is not technically feasible, there is no evidence that alternative procedures or techniques are better than LRN in terms of perioperative or QoL outcomes. In making treatment decisions, perioperative and QoL outcomes should be considered in conjunction with oncological outcomes. Overall, there was a paucity of data regarding QoL outcomes, and when reported, both QoL and perioperative outcomes were inconsistently defined, measured, or reported. The current evidence base has major limitations due to studies of low methodological quality marked by high risks of bias.(C) 2012 European Association of Urology. Published by Elsevier B. V. All rights reserved.
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| 27. |
- Millati, Ria, 1972, et al.
(författare)
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Ethanol from Oil Palm Empty Fruit Bunch via Dilute-Acid Hydrolysis and Fermentation by Mucor indicus and Saccharomyces cerevisiae
- 2011
-
Ingår i: Agricultural Journal. - : Medwell Journals. - 1994-4616 .- 1816-9155. ; 6:2, s. 54-59
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Tidskriftsartikel (refereegranskat)abstract
- Oil Palm Empty Fruit Bunch (OPEFB) was hydrolyzed in a one-stage hydrolysis using dilute-sulfuric acid (0.2, 0.8%) at 170-230°C with a holding time of 5 and 15 min. The maximum yield of xylose was 135.94 g kg-1 OPEFB, obtained at 0.8% acid, 190°C and 5 min. The maximum yield of glucose was 62.70 g kg-1 OPEFB, obtained at 0.8% acid, 210°C and 5 min. Based on these results, two-stage hydrolysis was performed to produce hydrolyzates for the fermentation process. Hydrolyzate from the first stage was fermented by Mucor indicus while the hydrolyzate from the second stage was fermented by Saccharomyces cerevisiae. The corresponding ethanol yields were 0.45 and 0.46 g ethanol g-1 sugar consumed.
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| 28. |
- Muhammad, Junaid, et al.
(författare)
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Two-domain formation during the epitaxial growth of GaN (0001) on c-plane Al2O3 (0001) by high power impulse magnetron sputtering
- 2011
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 110:12, s. 123519-
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Tidskriftsartikel (refereegranskat)abstract
- We study the effect of high power pulses in reactive magnetron sputter epitaxy on the structural properties of GaN (0001) thin films grown directly on Al2O3 (0001) substrates. The epilayers are grown by sputtering from a liquid Ga target, using a high power impulse magnetron sputtering power supply in a mixed N2/Ar discharge. X-ray diffraction, micro-Raman, micro-photoluminescence, and transmission electron microscopy investigations show the formation of two distinct types of domains. One almost fully relaxed domain exhibits superior structural and optical properties as evidenced by rocking curves with a full width at half maximum of 885 arc sec and a low temperature band edge luminescence at 3.47 eV with the full width at half maximum of 10 meV. The other domain exhibits a 14 times higher isotropic strain component, which is due to the higher densities of the point and extended defects, resulting from the ion bombardment during growth. Voids form at the domain boundaries. Mechanisms for the formation of differently strained domains, along with voids during the epitaxial growth of GaN are discussed.
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| 29. |
- Nilsson, Mats F., et al.
(författare)
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Improved methodology for identifying the teratogenic potential in early drug development of hERG channel blocking drugs
- 2010
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Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 29:2, s. 156-163
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Tidskriftsartikel (refereegranskat)abstract
- Drugs blocking the potassium current IKr of the heart (via hERG channel-inhibition) have the potential to cause hypoxia-related teratogenic effects. However, this activity may be missed in conventional teratology studies because repeat dosing may cause resorptions. The aim of the present study was to investigate an alternative protocol to reveal the teratogenic potential of IKr-blocking drugs. The IKr blocker astemizole, given as a single dose (80mg/kg) on gestation day (GD) 13 to pregnant rats caused digital defects. In whole rat embryo culture (2h) on GD 13, astemizole caused a decrease in embryonic heart rate at 20nM, and arrhythmias at 200-400nM. Cetirizine, without IKr-blocking properties, did not affect the rat embryonic heart in vitro. The present study shows that single dose testing on sensitive days of development, together with whole embryo culture, can be a useful methodology to better characterize the teratogenic potential of IKr-blocking drugs.
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| 30. |
- Pang, Andy W., et al.
(författare)
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Towards a comprehensive structural variation map of an individual human genome
- 2010
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Ingår i: Genome biology. - : Springer Science and Business Media LLC. - 1474-7596 .- 1465-6906. ; 11:5, s. R52-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Several genomes have now been sequenced, with millions of genetic variants annotated. While significant progress has been made in mapping single nucleotide polymorphisms (SNPs) and small (< 10 bp) insertion/deletions (indels), the annotation of larger structural variants has been less comprehensive. It is still unclear to what extent a typical genome differs from the reference assembly, and the analysis of the genomes sequenced to date have shown varying results for copy number variation (CNV) and inversions. Results: We have combined computational re-analysis of existing whole genome sequence data with novel microarray-based analysis, and detect 12,178 structural variants covering 40.6 Mb that were not reported in the initial sequencing of the first published personal genome. We estimate a total non-SNP variation content of 48.8 Mb in a single genome. Our results indicate that this genome differs from the consensus reference sequence by approximately 1.2% when considering indels/CNVs, 0.1% by SNPs and approximately 0.3% by inversions. The structural variants impact 4,867 genes, and >24% of structural variants would not be imputed by SNP-association. Conclusions: Our results indicate that a large number of structural variants have been unreported in the individual genomes published to date. This significant extent and complexity of structural variants, as well as the growing recognition of their medical relevance, necessitate they be actively studied in health-related analyses of personal genomes. The new catalogue of structural variants generated for this genome provides a crucial resource for future comparison studies.
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| 31. |
- Qadeer, Muhammad I., et al.
(författare)
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Anomalous high temperature oxidation of Sm 2(Fe,Co,Cu,Zr) 17 particles
- 2012
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 65, s. 453-460
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Tidskriftsartikel (refereegranskat)abstract
- Sm 2Co 17 alloys are attractive as high temperature permanent magnets; however their magnetic properties are prone to degrade by oxidation. The oxidation mechanism is not clearly understood, and inconsistent results are reported in the literature.This work correlates the oxidation of Sm 2(Co,Fe,Cu,Zr) 17 with microstructural and microchemical changes as a consequence of chemical reaction of alloy particles with their environment at high temperature. Thermogravimetric analysis suggests a change in oxidation mechanism occurs at 550°C. Energy dispersive X-ray spectroscopy suggests this is related to the loss of Sm by sublimation.
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| 32. |
- Qadeer, Muhammad Ifran, et al.
(författare)
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High temperature magnetic properties of Sm-Co and Sm-Co/polyamide-12 materials : effects of temperature, particle size, and silanization
- 2013
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 48:23, s. 8163-8170
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing demand for polymer-bonded magnets (PBM) in high temperature applications. While most research deals with high temperature properties of NdFeB-PBM, only a few studies consider Sm-Co PBM. Therefore, this study, on the thermal and magnetic properties of Sm-Co alloy powders and blends of these with polyamide-12 (PA12), was undertaken. Since the Sm-Co powders were the product of ball milling, they contained a variety of shapes and sizes. Studies on size fractions of these showed that the thermal stability and magnetic properties were improved as the particle size increased. It was suggested that higher residual strains and smaller crystallite sizes in the small particles were responsible for a decrease in the thermal stability and magnetic properties. In addition, energy dispersive X-ray spectroscopy revealed that the oxygen content increased with decreasing particle size (larger specific surface area) and higher oxygen content was possibly also responsible for a decrease in the magnetic properties. It was shown that, in general, the surface modification by silanization, using (3-aminopropyl)trimethoxsilane, increased the saturation magnetization and remanence of both the particles and the Sm-Co/PA12 composite. The silanization also improved the thermal stability of the particles.
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| 33. |
- Qadeer, Muhammad Ifran, et al.
(författare)
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Improved oxidation resistance of SmCo magnetic alloy powders by silanization
- 2013
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Ingår i: Progress in organic coatings. - : Elsevier BV. - 0300-9440 .- 1873-331X. ; 76:1, s. 94-100
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Forskningsöversikt (refereegranskat)abstract
- The thermal stability of Sm2Co17 powders coated with four different silanes was studied between 25 degrees C and 500 degrees C and isothermally at 400 degrees C. Thermogravimetry data indicated that the silane-based coatings provided improved oxidation resistance. The microstructural analysis of uncoated powders oxidized for 10 h at 400 degrees C revealed the formation of a featureless ca. 10 mu m thick shell, surrounding the unreacted core. The development of this shell was attributed to the inward diffusion of oxygen, decomposition of intermetallic phases and redistribution of alloying elements. The EDS elemental maps revealed that the shell was rich in O, Fe and Co, and depleted in Sm, Zr and Cu. In the presence of the silane-based coatings the thickness of the shell was reduced by more than 80% (to less than 2 mu m) and the redistribution of alloying elements was insignificant. Based on the thermogravimetric analysis at or above ca. 400 degrees C and the nnicrostructural analysis it was possible to assess the relative effectivity of the different silanes in preventing the oxidation of the SmCo powder. Methyltrimethoxysilane (MTMS), which also formed the thinnest coating, was the best silane. (3-Glycidyloxypropyl)trimethoxysilane, forming a thicker coating, was less effective than MTMS, but superior to the two amine-functionalized silanes ((3-aminopropyl)triethoxysilane and (3-aminopropyl)trimethoxysilane).
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| 34. |
- Qadeer, Muhammad I., et al.
(författare)
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Rheological and dynamic mechanical properties of polymer-bonded magnets based on Sm2Co17 and polyamide-12
- 2014
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Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 49:21, s. 7529-7538
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Tidskriftsartikel (refereegranskat)abstract
- The rheological and dynamic mechanical properties of polymer-based composites of Sm2Co17 and polyamide-12 with different particle loadings, sizes, and surface treatments are reported. Sm2Co17 particles were surface-treated with three different silanes: 3-glycidoxy(propyl)trimethoxysilane, 3-amino(propyl)trimethoxysilane (APTMS), and methyltrimethoxysilane (MTMS). It was shown, for the composites with untreated particles, that the viscosity and storage modulus increased with increasing filler content (0-60 vol%) and decreasing filler particle size. In addition, the glass transition temperature increased significantly and the damping decreased with increasing filler content. Of the silanes, the MTMS, which yielded only a thin surface layer, had in general the least effect on the rheological properties of the composite. The composite containing the APTMS-coated filler showed the highest storage modulus. The results give new insights on how to prepare polymer-bonded magnets with optimal process conditions (rheology) and dynamic mechanical properties, by varying the amount of particles, their size, and surface treatment.
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| 35. |
- Qadeer, Muhammad Ifran, et al.
(författare)
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The Effect of Silanisation on Microstructural Stability and Magnetic Properties of the Intermetallic Sm2(Co, Fe, Cu, Zr)17
- 2011
-
Ingår i: Materials Research Society Symposium Proceedings. - : Springer Science and Business Media LLC. - 0272-9172 .- 1946-4274. ; 1295, s. 443-448
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Tidskriftsartikel (refereegranskat)abstract
- The effects of silanising using the coupling agent γ-glycidoxpropyltrimethoxysilane on microstructural stability and magnetic properties of Sm-Co powder particles have been investigated. The silanisation provides structural stability by improving the oxidation resistance at 400oC for 10 hours. The untreated particles undergo microchemical changes by redistribution of alloying elements which mainly accumulate in parallel black and grey streaks in the interior of the particles. The silanised particles after heat treatment show coercivity of 836 Oe and the untreated particles show a much lower coercivity of 376 Oe. The difference in magnetic properties of uncoated particles is caused by diffusion of oxygen and microstructural instability.
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| 36. |
- Qureshi, Muhammad Tayyab, 1985, et al.
(författare)
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Passive Reciprocal high-pass/low-pass 4-bit phase shifter at 2.45 GHz
- 2014
-
Ingår i: 44th European Microwave Conference, EuMC 2014 - Held as Part of the 17th European Microwave Week, EuMW 2014; Fiera di RomaRome; Italy; 6 October 2014 through 9 October 2014. - 9782874870354 ; , s. 1076-1078
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the design, fabrication and measurement of a low cost, reciprocal 4-bit phase shifter at 2.45 GHz ISM band using COTS components. High-pass/low-pass filters in π configuration are used to implement the phase shifter bit sections. SPDT switches are realized with BAP51 dual PIN diodes, with resonant inductors in the off-state to provide high isolation. The driver circuit consisting of 74AHC240 octal buffer/inverter was implemented to switch the PIN diodes and control the phase states. A compact layout of the 4-bit phase shifter and driver circuitry was fabricated on a 4-layer FR4 substrate. The total size of the PCB board was 4.9×5.3 cm. The measurement results showed an RMS phase error better than 4.1°, insertion loss better than 8.8 dB and return loss better than 13 dB. The maximum power consumption of the 4-bit phase shifter was 80 mW.
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| 37. |
- Rahman, Muhammad J, et al.
(författare)
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Impact of Toll-like receptor 2 deficiency on immune responses to mycobacterial antigens
- 2011
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Ingår i: Infection and Immunity. - 0019-9567 .- 1098-5522. ; 79:11, s. 4649-4656
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we addressed the question of whether Toll-like receptor 2 (TLR2)-mediated innate immunity can contribute to the development of acquired immune responses. We immunized TLR2(-/-) and wild-type (WT) mice three times subcutaneously with the mycobacterial antigen (Ag19kDa) (a TLR2 ligand) or Ag85A (not a TLR2 ligand). One week after the last immunization, sera and spleens were collected. To evaluate cellular responses, we measured gamma interferon (IFN-γ) after in vitro restimulation of spleen cells with antigen alone or antigen-pulsed bone marrow-derived macrophages (BMM(Ag)) or pulmonary macrophages (PuM(Ag)). Antibody responses were comparable in the two mouse strains, but we observed differences in the cellular responses. Recall responses to Ag85A were similar in the two strains, but responses to Ag19kDa given alone or presented by BMM or PuM were lower in TLR2(-/-) than in WT mice. The largest differences in cellular responses were observed when Ag19kDa was presented by PuM. To understand this, we analyzed phenotypic and functional differences between BMM and PuM upon stimulation with various ligands. Generally, PuM had a lower response to the TLR2 ligand Pam(3)Cys-Ser-(Lys)(4) trihydrochloride and to anti-CD40 than BMM, as measured by cytokine secretion and upregulation of costimulatory molecules. This might provide a partial explanation for the lower capacity of PuM when pulsed with Ag19kDa, also a TLR2 ligand. Altogether, our results revealed weaknesses in the T cell and antigen-presenting cell (APC) compartments of the Ag19kDa-immunized TLR2(-/-) mice but indicated that specific immune responses could be generated in the absence of TLR2 regardless of the characteristics of the antigen used.
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| 38. |
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| 39. |
- Sjöland, Henrik, et al.
(författare)
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Ultra low power transceivers for wireless sensors and body area networks
- 2014
-
Ingår i: 2014 8th International Symposium on Medical Information and Communication Technology (ISMICT). - 2326-828X. - 9781479948567
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Konferensbidrag (refereegranskat)abstract
- A transceiver suitable for devices in wireless body area networks is presented. Stringent requirements are imposed by the high link loss between opposite sides of the body, about 85 dB in the 2.45 GHz ISM band. Despite this, minimum physical size and power consumption are required, and we target a transceiver with 1 mm2 chip area, 1 mW active power consumption, and data rate 250 kbit/s. The receiver is fully integrated., fabricated and measured in 65-nm CMOS, and size and power consumption are carefully considered at all levels of circuit and system design. The modulation is frequency shift keying, chosen because transmitters can be realized with high efficiency and low spurious emissions; a modulation index 2 creates a midchannel spectral notch. A direct-conversion receiver achieves minimum power consumption. A tailored demodulation structure makes the digital baseband compact and low power. The channel decoder has been implemented in both analog and digital domains to find the most power efficient solution. Antenna design and wave propagation are studied via simulations with phantoms. The 2.45 GHz ISM band was chosen as a good compromise between antenna size and link loss. An ultra-low power medium access scheme based on a duty-cycled wake-up receiver is designed.
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| 40. |
- Umair, Muhammad, et al.
(författare)
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Automatic frequency planning and optimization algorithm for cellular networks
- 2012
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Ingår i: Proceedings of the World Congress on Engineering 2012 Volume I & Volume II & Volume III. - : Newswood Limited. - 9789881925213 ; , s. 1287-1291
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Konferensbidrag (refereegranskat)abstract
- Frequency planning in ever growing cellular networks is an extremely arduous task. Any effort to lay down manual frequency plans promulgates inefficiency in the cellular radio systems. The extensive deployment and penetration of cellular networks necessitate the need to carry out automatic frequency planning. This paper presents a novel and ingenious algorithm for automatic generation and optimization of the frequency plan whereby curtailing the intra-system interference levels within the acceptable ranges of the key performance indicators (KPI’s) defined for any real time cellular network. The automatic frequency planning and optimization has been done using the concept of Inter-Cell Dependency Matrix (ICDM) which contains cell correlations in terms of the affect one cell has on the other primarily with regards to the co-channel interference. The proposed algorithm was simulated in MATLAB. It has been set forth and tested using inputs from live network data. It has been found to satisfy the verifiable network performance metrics.
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| 41. |
- Yang, Li Li, 1980-, et al.
(författare)
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Indirect optical transition due to surface band bending in ZnO nanotubes
- 2010
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Ingår i: Journal of Applied Physics. - : American Institute. - 0021-8979 .- 1089-7550. ; 108:10
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Tidskriftsartikel (refereegranskat)abstract
- ZnO nanotubes (ZNTs) have been successfully evolved from ZnO nanorods (ZNRs) by a simple chemical etching process. Two peaks located at 382 nm and 384 nm in the UV emission region has been observed in the room temperature photoluminescence (PL) spectrum of ZNTs since the surface band bending in ZNTs induces the coexistence of indirect and direct transitions in their emission process. In addition, a strong enhancement of total luminescence intensity at room temperature in ZNTs has also be observed in comparison with that of ZNRs. Both temperature-dependent PL and time-resolved PL results not only further testify the coexistence of indirect and direct transitions due to the surface band bending, but also reveal that less nonradiative contribution to the emission process in ZNTs finally causes their stronger luminescence intensity.
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| 42. |
- Århammar, C., et al.
(författare)
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Probing temperature-induced ordering in supersaturated Ti-1 (-) xAlxN coatings by electronic structure
- 2014
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 242, s. 207-213
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Tidskriftsartikel (refereegranskat)abstract
- The ordering of supersaturated cubic titanium aluminum nitride (c-Ti0.35Al0.65N) coatings is probed from room temperature up to and above the point of spinodal decomposition, using Near Edge X-ray Absorption Fine-structure (NEXAFS) and first principles calculations. The measured and calculated nitrogen (N) K spectra suggest that unoccupied N p states hybridize with Ti d states. When temperature is raised the N p-Ti d overlap decreases, whereas hybridization between N p and Al p tends to increase. The observed spectral changes with temperature together with calculations of defect heat of formation suggest a depletion of N in the surroundings of Ti in c-Ai(1) (-) xAlxN and/or in the formed c-TiN.
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