| 1. |
- Bailey-Wilson, Joan E, et al.
(författare)
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Analysis of Xq27-28 linkage in the international consortium for prostate cancer genetics (ICPCG) families
- 2012
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Ingår i: BMC Medical Genetics. - London : BioMed Central. - 1471-2350. ; 13, s. 46-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genetic variants are likely to contribute to a portion of prostate cancer risk. Full elucidation of the genetic etiology of prostate cancer is difficult because of incomplete penetrance and genetic and phenotypic heterogeneity. Current evidence suggests that genetic linkage to prostate cancer has been found on several chromosomes including the X; however, identification of causative genes has been elusive.Methods: Parametric and non-parametric linkage analyses were performed using 26 microsatellite markers in each of 11 groups of multiple-case prostate cancer families from the International Consortium for Prostate Cancer Genetics (ICPCG). Meta-analyses of the resultant family-specific linkage statistics across the entire 1,323 families and in several predefined subsets were then performed.Results: Meta-analyses of linkage statistics resulted in a maximum parametric heterogeneity lod score (HLOD) of 1.28, and an allele-sharing lod score (LOD) of 2.0 in favor of linkage to Xq27-q28 at 138 cM. In subset analyses, families with average age at onset less than 65 years exhibited a maximum HLOD of 1.8 (at 138 cM) versus a maximum regional HLOD of only 0.32 in families with average age at onset of 65 years or older. Surprisingly, the subset of families with only 2-3 affected men and some evidence of male-to-male transmission of prostate cancer gave the strongest evidence of linkage to the region (HLOD = 3.24, 134 cM). For this subset, the HLOD was slightly increased (HLOD = 3.47 at 134 cM) when families used in the original published report of linkage to Xq27-28 were excluded.Conclusions: Although there was not strong support for linkage to the Xq27-28 region in the complete set of families, the subset of families with earlier age at onset exhibited more evidence of linkage than families with later onset of disease. A subset of families with 2-3 affected individuals and with some evidence of male to male disease transmission showed stronger linkage signals. Our results suggest that the genetic basis for prostate cancer in our families is much more complex than a single susceptibility locus on the X chromosome, and that future explorations of the Xq27-28 region should focus on the subset of families identified here with the strongest evidence of linkage to this region.
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| 2. |
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| 3. |
- Lu, Lingyi, et al.
(författare)
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Chromosomes 4 and 8 implicated in a genome wide SNP linkage scan of 762 prostate cancer families collected by the ICPCG
- 2012
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Ingår i: The Prostate. - : Wiley. - 0270-4137 .- 1097-0045. ; 72:4, s. 410-426
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND In spite of intensive efforts, understanding of the genetic aspects of familial prostate cancer (PC) remains largely incomplete. In a previous microsatellite-based linkage scan of 1,233 PC families, we identified suggestive evidence for linkage (i.e., LOD?=?1.86) at 5q12, 15q11, 17q21, 22q12, and two loci on 8p, with additional regions implicated in subsets of families defined by age at diagnosis, disease aggressiveness, or number of affected members. METHODS. In an attempt to replicate these findings and increase linkage resolution, we used the Illumina 6000 SNP linkage panel to perform a genome-wide linkage scan of an independent set of 762 multiplex PC families, collected by 11 International Consortium for Prostate Cancer Genetics (ICPCG) groups. RESULTS. Of the regions identified previously, modest evidence of replication was observed only on the short arm of chromosome 8, where HLOD scores of 1.63 and 3.60 were observed in the complete set of families and families with young average age at diagnosis, respectively. The most significant linkage signals found in the complete set of families were observed across a broad, 37cM interval on 4q13-25, with LOD scores ranging from 2.02 to 2.62, increasing to 4.50 in families with older average age at diagnosis. In families with multiple cases presenting with more aggressive disease, LOD cores over 3.0 were observed at 8q24 in the vicinity of previously identified common PC risk variants, as well as MYC, an important gene in PC biology. CONCLUSIONS. These results will be useful in prioritizing future susceptibility gene discovery efforts in thiscommon cancer. Prostate 72: 410-426, 2012. (C) 2011 Wiley Periodicals, Inc.
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| 5. |
- Golovitchev, Valeri, 1945, et al.
(författare)
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Development of dual fuel combustion models for direct injected heavy duty diesel engines
- 2013
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Ingår i: Diesel Fuels: Characteristics, Performances and Environmental Impacts. - 9781626188662 ; , s. 85-118
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- A new model incorporating two combustion modes was developed to simulate dualfuel(DF) combustion engines with different fuel compositions (natural gas/diesel oil andmethanol/dimethyl ether (DME)). The model involved two coupled combustion modes: a"conventional" partially premixed reactor diesel mode and a flame propagation mode.For the flame propagation combustion mode, an expression for the reaction rate wasdeduced based on the equation for the flame speed. Laminar flame speeds for theaspirated fuels were calculated using the PREMIX code within the Chemkin-2 packageby using the chemical mechanisms for the fuel compositions and species moleculartransport properties and were subsequently fitted to polynomial expressions. Theturbulent flame speed was assumed to depend on the laminar speed and characteristics offlow turbulence.CFD partial and full cycle engine simulations were performed for two heavy dutydiesel engines, a Volvo D12C and an IF (Isotta Fraschini), using the 3D CFD KIVA3Vand KIVA4 codes supplemented by similar spray models and semi-detailed combustionand emission formation mechanisms for both fuel compositions. The natural gas fuel wasselected as a four-component mixture of methane (>90%), ethane, propane and n-butane,while diesel oil vapor was represented as a blend of n-heptane and toluene. The solutionalgorithm accounted for the two coupled combustion modes by employing aninterpolation procedure. The predicted DF engine in-cylinder parameters (pressure,energy release rate, NOx and H2O/CO2 concentrations) and combustion efficiencies forhe different DF compositions were compared with conventional diesel data for bothengines.
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| 6. |
- Imren, A., et al.
(författare)
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The Full Cycle HD diesel Engine Simulation using KIVA-4 Code
- 2010
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; , s. 20-
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Konferensbidrag (refereegranskat)abstract
- With the advent of the KIVA-4 code which employs an unstructured mesh to represent the engine geometry, the gap in flexibility between commercial and research modeling software becomes more narrow. In this study, we tried to perform a full cycle simulation of a 4-stroke HD diesel engine represented by a highly boosted research IF (Isotta Fraschini) engine using the KIVA-4 code. The engine mesh including the combustion chamber, intake and exhaust valves and helical manifolds was constructed using optional O-Grids catching a complex geometry of the engine parts with the help of the ANSYS ICEM CFD software. The KIVA-4 mesh input was obtained by a homemade mesh converter which can read STAR-CD and CFX outputs. The simulations were performed on a full 360 deg mesh consisting of 300,000 unstructured hexahedral cells at BDC. The physical properties of the liquid fuel were taken corresponding to those of real diesel #2 oil. The spray atomization and droplet dynamics models were described by the KH-RT hybrid model which is a modified replica of the ERC model; the droplet collisions were modeled by the droplet-trajectory-based method with a reduced grid dependency. The original KIVA-4 droplet evaporation model was replaced by the KIVA-3V model. Chemical kinetics (71 species, 323 reactions) was based on the mechanism for diesel oil surrogate represented by a blend of n-heptane (70%) and toluene (30%) coupled with the EDC (eddy dissipation concept) model to simulate turbulent combustion. The emission (soot and NO\dx) formations were described in terms of sub-models based on the evolution of soot precursors, A2R5, and the extended Zel'dovich mechanism, respectively. All stages of the engine cycle were successfully calculated. Due to a small amount of experimental data available for the research IF engine, predictions were successfully compared with experimental data on the in-cylinder pressure and RoHR (rate of heat release) histories only. Comparisons of the predictions produced on the full and sector meshes were also made.
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| 7. |
- Mattarelli, E., et al.
(författare)
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CFD-3D Analysis of a Light Duty Dual Fuel (Diesel/Natural Gas) Combustion Engine
- 2014
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 45, s. 929-937
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Konferensbidrag (refereegranskat)abstract
- Nowadays, the most critical issues concerning internal combustion engines are the reduction of the pollutant emissions, in particular of CO2, and the replacement of fossil fuels with renewable sources. An interesting proposition for Diesel engines is the Dual Fuel (DF) combustion, consisting in the ignition of a premixed charge of gaseous fuel (typically natural gas) by means of a pilot injection of Diesel Fuel. Dual fuel combustion is a quite complex process to model, since it includes the injection of liquid fuel, superimposed with a premixed combustion. However, CFD simulation is fundamental to address a number of practical issues, such as the setting of the liquid injection parameters and of the gaseous fuel metering, as well as to get the maximum benefit from the DF technique. In this paper, a customized version of the KIVA-3V Computational Fluid Dynamic (CFD) code was adopted to analyze the combustion process of a 4-cylinder, 2.8 l, turbocharged HSDI Diesel engine, operating in both Diesel and DF (Diesel and Natural Gas) modes. Starting from a previously validated diesel combustion model, a natural gas combustion model was implemented and added to simulate the DF operations. Available engine test data were used for validation of the diesel-only operation regimes. Using the calibrated model, the influence of the premixed charge composition was investigated, along with the effect of the diesel injection advance angle, at a few characteristic operating conditions. An optimum setting was eventually found, allowing the DF engine to deliver the same brake power of the original Diesel unit, yielding the same maximum in-cylinder pressure.It was found that DF combustion is soot-less, yields a strong reduction of CO and CO2, but also an increase of NO.
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| 8. |
- Mattarelli, E., et al.
(författare)
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Combustion optimization of a marine di diesel engine
- 2013
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Enhanced calibration strategies and innovative engine combustion technologies are required to meet the new limits on exhaust gas emissions enforced in the field of marine propulsion and on-board energy production. The goal of the paper is to optimize the control parameters of a 4.2 dm3 unit displacement marine DI Diesel engine, in order to enhance the efficiency of the combustion system and reduce engine out emissions. The investigation is carried out by means of experimental tests and CFD simulations. For a better control of the testing conditions, the experimental activity is performed on a single cylinder prototype, while the engine test bench is specifically designed to simulate different levels of boosting. The numerical investigations are carried out using a set of different CFD tools: GT-Power for the engine cycle analysis, STAR-CD for the study of the in-cylinder flow, and a customized version of the KIVA-3V code for combustion. All the models are calibrated through the above mentioned experimental campaign. Then, CFD simulations are applied to optimize the injection parameters and to explore the potential of the Miller combustion concept. It is found that the reduction of the charge temperature, ensuing the adoption of an early intake valve closing strategy, strongly affects combustion. With a proper valve actuation strategy, an increase of boost pressure and an optimized injection advance, a 40% reduction of NOx emissions can be obtained, along with a significant reduction of in-cylinder peak pressure, without penalizing fuel efficiency.
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| 9. |
- Raidén, A.B., et al.
(författare)
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Juggling work, family... and life in academia: The case of the "new" man
- 2012
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Ingår i: 28th Annual Conference of the Association of Researchers in Construction Management, ARCOM 2012; Edinburgh; United Kingdom; 3 September 2012 through 5 September 2012. - 9780955239069 ; , s. 273-283
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Konferensbidrag (refereegranskat)abstract
- Although the notion of the "new man" is gaining currency, there is very little research on how he manages to balance work and family. It is therefore timely to look moreclosely at this issue. We present preliminary results from an explorative pilot study onwork-life balance and "new men" in academia. Using an interprative approach, in-depth interviews were carried out with academics from construction-related universitydepartments in Britain and Sweden. Drawing on figures from the OECD and on Hofstede's masculine (Britain)/feminine (Sweden) dimension, we found that the smallpopulation of academic respondents studied struggled with the same kinds of workpressures and desires to achieve/perform according to the traditional norm of amasculine society. However, the Swedish men were more inclusive of the wholefamily life/circumstances in their accounts while the British men tended to be morefocused on themselves. Since the analysis of the data is still on-going, the findingsremain tentative. Early conclusions suggest that a satisfactory juggling of work-lifebalance for all these men is dependent on negotiations and re-negotiations ofresponsibilities between them and their partners. Some British men seemed to expectcompromise and sacrifice by their partners, while for all Swedish men there was anexpectation of compromise and sacrifice by both partners.
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| 10. |
- Rinaldini, C.A., et al.
(författare)
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Potential of the Miller cycle on a HSDI diesel automotive engine
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 112, s. 102-119
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Tidskriftsartikel (refereegranskat)abstract
- The paper explores, by means of CFD simulations, the potential of the Miller cycle, applied to High Speed Direct Injection (HSDI) Diesel engines, facing the challenge of emissions reduction enforced by the nearterm regulations, with particular reference to Euro VI. In fact, a valuable benefit of the Miller technique is the strong reduction of combustion temperature, thus the abating of NOx emissions, compared to a traditional cycle with the same values of AFR and EGR rate. The practical application of the Miller cycle yields a number of critical issues, which are generally addressed in the paper. However, the goal of the study is to assess the potential and the limits of this technique, more than develop a specific engine configuration. For the analysis, a 2.8 L 4-cylinder turbocharged engine produced by VM Motori was selected, carrying out a comprehensive experimental campaign, at both full and partial load. The experimental data allowed the authors to calibrate two types of numerical models, one for the whole engine analyses (0/1D), the other for the combustion process simulation (CFD-3D). The integrated use of these computational tools provides a reliable comparison between the base engine and the one modified according to the Miller cycle, in terms of both emissions and fuel consumption in the European Driving Cycle. It was found a reduction of NOx and Soot of 25% and 60%, respectively, and a worsening of fuel efficiency of 2%. The abating of NOx can be further enhanced, since it is demonstrated that the engine operated according to the Miller cycle can tolerate higher rates of EGR. (C) 2013 Elsevier Ltd. All rights reserved.
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