| 1. |
- Goey, Kaitlyn K. H., et al.
(författare)
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Consensus statement on essential patient characteristics in systemic treatment trials for metastatic colorectal cancer : Supported by the ARCAD Group
- 2018
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Ingår i: European Journal of Cancer. - : ELSEVIER SCI LTD. - 0959-8049 .- 1879-0852. ; 100, s. 35-45
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patient characteristics and stratification factors are key features influencing trial outcomes. However, there is substantial heterogeneity in reporting of patient characteristics and use of stratification factors in phase 3 trials investigating systemic treatment of metastatic colorectal cancer (mCRC). We aimed to develop a minimum set of essential baseline characteristics and stratification factors to include in such trials. Methods: We performed a modified, two-round Delphi survey among international experts with wide experience in the conduct and methodology of phase 3 trials of systemic treatment of mCRC. Results: Thirty mCRC experts from 15 different countries completed both consensus rounds. A total of 14 patient characteristics were included in the recommended set: age, performance status, primary tumour location, primary tumour resection, prior chemotherapy, number of metastatic sites, liver-only disease, liver involvement, surgical resection of metastases, synchronous versus metachronous metastases, (K)RAS and BRAF mutation status, microsatellite instability/mismatch repair status and number of prior treatment lines. A total of five patient characteristics were considered the most relevant stratification factors: RAS/BRAF mutation status, performance status, primary tumour sidedness and liver-only disease. Conclusions: This survey provides a minimum set of essential baseline patient characteristics and stratification factors to include in phase 3 trials of systemic treatment of mCRC. Inclusion of these patient characteristics and strata in study protocols and final study reports will improve interpretation of trial results and facilitate cross-study comparisons.
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| 2. |
- Akkerman, V., et al.
(författare)
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Flow-flame interaction in a closed chamber
- 2008
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Ingår i: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 20:5, s. 21-
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Tidskriftsartikel (refereegranskat)abstract
- Numerous studies of flame interaction with a single vortex and recent simulations of burning in vortex arrays in open tubes demonstrated the same tendency for the turbulent burning rate proportional to U-rms lambda(2/3), where U-rms is the root-mean-square velocity and lambda is the vortex size. Here, it is demonstrated that this tendency is not universal for turbulent burning. Flame interaction with vortex arrays is investigated for the geometry of a closed burning chamber by using direct numerical simulations of the complete set of gas-dynamic combustion equations. Various initial conditions in the chamber are considered, including gas at rest and several systems of vortices of different intensities and sizes. It is found that the burning rate in a closed chamber (inverse burning time) depends strongly on the vortex intensity; at sufficiently high intensities it increases with U-rms approximately linearly in agreement with the above tendency. On the contrary, dependence of the burning rate on the vortex size is nonmonotonic and qualitatively different from the law lambda(2/3). It is shown that there is an optimal vortex size in a closed chamber, which provides the fastest total burning rate. In the present work, the optimal size is six times smaller than the chamber height.
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| 3. |
- Goey, Kaitlyn K. H., et al.
(författare)
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Reporting of patient characteristics and stratification factors in phase 3 trials investigating first-line systemic treatment of metastatic colorectal cancer : A systematic review
- 2018
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049 .- 1879-0852. ; 96, s. 115-124
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Forskningsöversikt (refereegranskat)abstract
- Background: Patient characteristics and stratification factors are important factors influencing trial outcomes. Uniform reporting on these parameters would facilitate cross-study comparisons and extrapolation of trial results to clinical practice. In 2007, standardisation on patient characteristics reporting and stratification in metastatic colorectal cancer (mCRC) trials was proposed. We investigated the reporting of prognostic factors and implementation of this proposal in mCRC trials published from 2005 to 2016.Methods: We searched PubMed and Embase (January 2005 – June 2016) for first-line phase 3 mCRC trials. Patient characteristics reporting and use of stratification factors were extracted and analysed for adherence to the proposal from 2007.Results: Sixty-seven trials (35,315 patients) were identified, reporting 48 different patient characteristics (median: 9 [range: 5–18] per study). Age, gender, performance status (PS), primary tumour site and adjuvant chemotherapy were frequently reported (87%–100%), in contrast to laboratory values, such as alkaline phosphatase, lactate dehydrogenase and white blood cell count (10%–25%). We identified 29 different stratification factors (median: 3 [range: 1–9] per study). The most common strata were PS and treatment centre (>60%). A median of 8/12 (range: 4–11) of the proposed parameters was reported. Although the percentage of studies reporting each factor slightly increased over time, there was no significant correlation between publication year and adherence to the proposal from 2007.Conclusions: We observed persistent heterogeneity in the reporting of patient characteristics and use of stratification factors in first-line mCRC trials. The proposal from 2007 has not led to increased uniformity of patient characteristics reporting and use of stratification over time. There is an urgent need to address this issue to improve the interpretation of trial results.
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| 4. |
- Prins, A. J., et al.
(författare)
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Visualization of Biomass Pyrolysis and Temperature Imaging in a Heated-Grid Reactor
- 2009
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 23:1, s. 993-1006
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Tidskriftsartikel (refereegranskat)abstract
- The main advantage of a heated-grid reactor for studying pyrolysis kinetics of solid fuel samples is that high heating rates of up to 1000 K/s can be obtained. However, one of the concerns is whether the temperature distribution over the grid material is uniform and whether the presence of a thermocouple welded to the grid causes any measurement errors. Biomass samples were placed on the heated-grid reactor, and the volatiles, emitted in the biomass pyrolysis process as hot gas plumes, were imaged with an infrared camera with a high framing speed. The temporal resolved infrared images indicate that the pyrolysis process does not take place at the same rate everywhere on the grid. Two-dimensional temperature images of a heated grid made of stainless steel were recorded using the method of laser-induced thermometry with thermographic phosphors. As expected from a heat-transfer model, measured temperatures were found to be significantly higher than temperatures indicated by a thermocouple welded to the bottom of the grid. It was also observed that there is a large temperature gradient between the two electrodes on which the grid is connected. It is shown that replacing a wire mesh by a foil as a grid material may lead to more homogeneous temperature distribution. The paper recommends additional research to demonstrate the suitability of the heated-grid reactor for carrying out accurate measurements.
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| 5. |
- Prins, M. J., et al.
(författare)
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Biomass pyrolysis in a heated-grid reactor: Visualization of carbon monoxide and formaldehyde using Laser-Induced Fluorescence
- 2011
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier BV. - 1873-250X .- 0165-2370. ; 92:2, s. 280-286
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Tidskriftsartikel (refereegranskat)abstract
- The development of improved biomass pyrolysis models is vital for more accurate modelling and design of biomass conversion equipment. Such improved models must be based on reliable experimental data: biomass should be pyrolyzed at high heating rates and the reaction products should be measured using an on-line, non-intrusive method. Therefore, a heated grid reactor with heating rate of 300-600 K/s was used to study pyrolysis of biomass at temperatures in the range of 500-700 degrees C. The formation of formaldehyde and carbon monoxide from wood at high heating rates was successfully visualized using Laser-Induced Fluorescence (LIF). A thin vertical laser line or sheet was present directly above the biomass lying on the heated grid. Two-photon excitation at 230 nm was applied to induce fluorescence of carbon monoxide present in the volatiles, whereas excitation of formaldehyde was done at 355 nm. Visualization of these compounds shows that the release rises strongly with temperature; this typically happens on a timescale in the order of seconds. In principle, the method described allows for the determination of truly primary products. Future research is recommended, aimed at quantifying the concentrations measured by LIE. Care must be taken to calibrate for quenching of the fluorescence signal. Avoiding secondary reactions taking place in the gas phase is another experimental challenge. (C) 2011 Elsevier B.V. All rights reserved.
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| 6. |
- Raida, M. B., et al.
(författare)
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Laminar burning velocity measurements of ethanol+air and methanol+air flames at atmospheric and elevated pressures using a new Heat Flux setup
- 2021
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 230
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Tidskriftsartikel (refereegranskat)abstract
- A new setup for burning velocity measurements of liquid fuels at elevated pressures using the Heat Flux method has been constructed. The burner design has been improved comparing to previous studies in this and other laboratories. Laminar burning velocities were determined experimentally for ethanol+air and methanol+air mixtures over a range of conditions including equivalence ratio (0.8 to 1.3), inlet gas temperature (318–338 K), and pressure (1–5 bar). Experimental uncertainties have been determined and analyzed. The overall accuracy of the burning velocity, SL, was evaluated to be better than ±1 cm/s for atmospheric pressure and ±1.5 cm/s at elevated pressure conditions. Experimental results at 1 atm are in good agreement with recent literature data. To compare the present measurements with the literature data often obtained at other initial temperatures and pressures, an empirical expression SL = SL0 (T/T0)α (p/p0)β, which correlates the burning velocity at a specific temperature, T, and pressure, p, with that at standard conditions indicated by superscripts 0, was implemented. At a fixed temperature, pressure dependence at each equivalence ratio can be analyzed. It was found that power exponents β derived in the present work and from the literature data possess large scattering. The best agreement was found between the present results and experimental literature data from spherical flames using non-linear stretch correction models. Burning velocities at atmospheric as well as elevated pressures and power exponents β have been also compared with kinetic modeling results using several detailed kinetic mechanisms, showing a fair to a good agreement. As the new results are accurate and free from stretch effects, they form a new source of reliable data for validation of the reaction mechanisms.
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| 7. |
- Verhoeven, L. M., et al.
(författare)
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A numerical and experimental study of Polycyclic Aromatic Hydrocarbons in a laminar diffusion flame
- 2013
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 34, s. 1819-1826
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Tidskriftsartikel (refereegranskat)abstract
- During the process of biomass gasification tars are formed which exit the gasifier in vapor phase. Tar condensation creates problems like fouling and plugging of after-treatment, conversion and end-use equipment. Gasification tars consist mainly of Polycyclic Aromatic Hydrocarbons (PAHs). Former research has shown the possibilities and difficulties of tar conversion by partial combustion. Basic studies to investigate the oxidation of tars in non-premixed combustion processes are expected to give more insight in this problem. In this paper the ability of the flamelet-generated manifold (FGM) approach to numerically model multi-dimensional, laminar, non-premixed flames with the inclusion of PAH chemistry is investigated. Modeling detailed PAH chemistry requires the employment of large reaction mechanisms which lead to expensive numerical calculations. The application of a reduction technique like FGM leads to a considerable decrease (up to two orders) in the required computation time. A 1D numerical validation shows that the improvements achieved by implementing a varying Lewis number for the progress variable Y are significant for PAH species with a large Lewis number, such as C10H8. Considerable improvements are found near the flame front and on the fuel side of the flame. A comparison has been made of FGM results with qualitative Planar Laser Induced Fluorescence (PLIF) measurements. A laminar CH4/N-2-air co-flow flame has been doped with two dopants, benzene and toluene, at three different concentrations. A set of filters was used in order to qualitatively distinguish the small (1-2 rings) and large (3 or more rings) aromatic species. The results show that the model is able to capture the major flame characteristics typical for PAH formation in multi-dimensional laminar non-premixed flames. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 8. |
- Yu, J. F., et al.
(författare)
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Heat transfer and flame stabilization of laminar premixed flames anchored to a heat-flux burner
- 2016
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Ingår i: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199. ; 41:3, s. 2037-2051
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Tidskriftsartikel (refereegranskat)abstract
- Measurement of the burning velocity of unstretched laminar hydrogen/air premixed flames suffers from large uncertainties owing to the highly diffusive nature of hydrogen that can give rise to flame instability. This paper reports on a numerical study of the structures and stability of laminar premixed CH4/O2/CO2 flames and H2/O2/N2 flames anchored to a heat-flux burner using a high-order numerical method with detailed chemical kinetic mechanisms and detailed transport properties. The aim is to elucidate the effect of the flow and temperature inhomogeneity generated by the burner plate holes on flame structures and burning velocity. Heat transfer flux between the burner plate and the surrounding gaseous mixture is investigated under various standoff distances and burner plate temperatures. The burning velocity and the detailed flow, temperature and species distributions in flames with a zero net heat flux between the flames and the burner plate are analyzed. It is found that for the methane flames, when the standoff distance is sufficiently small, the burner can essentially suppress the intrinsic flame instability, but the plate holes can give rise to flame wrinkles of the size of the holes. At high standoff distances, the non-uniformity of the flow from the burner plate holes has a minor effect on the flame surface wrinkling; however, large-scale cellular structures can appear on the flame surface due to intrinsic flame instability. For the studied methane flames the effect of non-uniformity of the flow from the burner plate holes on the burning velocity is fairly small. For the studied hydrogen flames the burner plate could not totally suppress the intrinsic flame instability. The intrinsic flame instability can give rise to a significant increase in the flame surface area and mean burning velocity, with more than 25% increase in the burning velocity.
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| 9. |
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