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91.
Matteo Lualdi Sara Lögdberg Francesco Regali Magali Boutonnet Sven Järås 《Topics in Catalysis》2011,54(13-15):977-985
A series of different mechanical mixtures of a narrow-pore Co/γ-Al2O3 catalyst and a Cu-based WGS-catalyst has been investigated in the low-temperature Fischer–Tropsch synthesis (483 K, 20 bar) with a model bio-syngas (H2/CO = 1.0) in a fixed-bed reactor. The higher the fraction of WGS-catalyst in the mixture, the lower is the Co-catalyst-time yield to hydrocarbons. This is ascribed to a strong positive kinetic effect of water on the Fischer–Tropsch rate of the Co-catalyst, showing the importance of the indigenously produced water, especially in fixed-bed reactors where the partial pressure of water is zero at the reactor inlet. A preliminary kinetic modeling suggests that the reaction order in P $ _{{{\text{H}}_{ 2} {\text{O}}}} $ is 0.3 for the Co/γ-Al2O3 catalyst in the range of the studied reactor-average partial pressures of water (i.e., 0.04–1.2 bar). 相似文献
92.
Valerie Guillet Magali Vatton Gaëlle Guehenneux Patrick Baussand 《Polycyclic Aromatic Compounds》2013,33(3-4):589-599
Dioxins are among aromatic compounds that at present arouse the most part of discussions as environment pollutants. In the present works from the French norm AFNOR, there is no simple way of sampling and analysis for gas emissions. Solid-phase microextraction (SPME) proves to be an adapted technology for dioxin sampling in gaseous phase due to its rapidity, reliability, and simplicity of material. In this study, a sample preparation method with a 100 w m polydimethylsiloxane fiber interfaced with a gas chromatography has been optimized for a monochlorinated dibenzo- p -dioxin: exposure of the fiber into the gaseous sample during 1 hr at 125°C. The partition coefficient fiber/matrix of the 1-monochlorinated dibenzo- p -dioxin has also been calculated versus temperature (K = 5.85 at 125°C). 相似文献
93.
Film-boiling heat transfer is a key phenomenon governing severe accident sequence in a sodium-cooled fast reactor. Experimental the fuel-coolant interaction process which may occur during a and theoretical work on film-boiling heat transfer in sodium has hardly been carried out in the past. An experiment has been conducted in the early seventies to investigate sodium pool boiling. In this experiment, a hot tantalum sphere was immersed into subcooled liquid sodium. Film boiling was obtained for various sets of parameters: sodium subcooling from 4.1 K to 29. 1 K, initial sphere temperature ranging from 1,802.6 K to 2,633.7 K, sphere diameters of 1.27, 1.91 and 2.54 cm and sodium depths of 7.6 cm and 11.4 cm. In the present work, a simplified analysis based on the boundary layer theory is developed to describe pool film-boiling heat transfer on a hot sphere in liquid sodium. Two extreme cases are considered depending on sodium subcooling. In the case of high subcooling, most of the heat lost by the sphere is used to heat the sodium while for low subcooling, it is used to vaporize the liquid at the liquid-vapor interface. It will be shown that the scaling analysis predicts the heat fluxes within the order of magnitude when compared to the available experimental data. Besides, it allows an estimation of the contribution of these fluxes to the liquid heating and vaporization processes. 相似文献
94.
Separation of metals in the cationic form is the basis of hydrometallurgy. Ion-specific separation is achieved via selective transfer between liquid phases that have been emulsified in order to be in “close” contact. We show here how the organization of water-in-oil (w/o) “reverse” aggregates in the solvent phase controls the free energy of transfer of cations in the form of neutral salts between phases. Indeed, all known efficient ion separation mechanisms rely on complex fluids in the Winsor II regime, i.e. when a concentrated mixed salt solution is in equilibrium with a solvent phase containing self-assembled aggregates. Here, we point out that, in the general case of water-poor complex fluids containing extractant molecules, long-range interactions linked to w/o interface curvature participate in the selectivity of any multivalent ion extraction process. The free energy related to ion transfer between phases, i.e. the extraction free energy, is different from the complexation free energy. This difference is the key to the selectivity of the separation process. We give here general expressions linking complexation free energy and transfer free energy as derived from known adsorption isotherms, taking into account interfacial curvature, considered as a generalized scalar related to the packing near the interface. 相似文献
95.
Antonio Bisconsin-Junior Amauri Rosenthal Magali Monteiro 《Food and Bioprocess Technology》2014,7(6):1670-1677
The influence of high hydrostatic pressure (HHP) on Pêra Rio orange juice was investigated using response surface methodology. A central composite design was used to evaluate the effects of three processing conditions (independent variables), namely pressure (100–600 MPa), temperature (30–60 °C) and time (30–360 s), on the native microflora and pectin methylesterase (PME) activity of orange juice. Analysis of variance showed that second-order polynomial models fitted well with the experimental data for PME residual activity (R 2?=?0.9586, p?<?0.001) and aerobic microorganism count (R 2?=?0.9879, p?<?0.001). The optimum HHP processing conditions to produce orange juice with PME residual activity of less than 20 % and low microorganism count (<2 log cycles CFU/mL) were 550 to 600 MPa, 55 to 60 °C and 330 to 360 s. 相似文献
96.
Thu Hang Lai Susann Schrder Magali Toussaint Sladjana Duki-Stefanovi Mathias Kranz Friedrich-Alexander Ludwig Steffen Fischer Jrg Steinbach Winnie Deuther-Conrad Peter Brust Rare-Petru Moldovan 《International journal of molecular sciences》2021,22(5)
The adenosine A2A receptor (A2AR) represents a potential therapeutic target for neurodegenerative diseases. Aiming at the development of a positron emission tomography (PET) radiotracer to monitor changes of receptor density and/or occupancy during the A2AR-tailored therapy, we designed a library of fluorinated analogs based on a recently published lead compound (PPY). Among those, the highly affine 4-fluorobenzyl derivate (PPY1; Ki(hA2AR) = 5.3 nM) and the 2-fluorobenzyl derivate (PPY2; Ki(hA2AR) = 2.1 nM) were chosen for 18F-labeling via an alcohol-enhanced copper-mediated procedure starting from the corresponding boronic acid pinacol ester precursors. Investigations of the metabolic stability of [18F]PPY1 and [18F]PPY2 in CD-1 mice by radio-HPLC analysis revealed parent fractions of more than 76% of total activity in the brain. Specific binding of [18F]PPY2 on mice brain slices was demonstrated by in vitro autoradiography. In vivo PET/magnetic resonance imaging (MRI) studies in CD-1 mice revealed a reasonable high initial brain uptake for both radiotracers, followed by a fast clearance. 相似文献
97.
Kurniawan Mario Stich Michael Marimon Mayra Camargo Magali Peipmann Ralf Hannappel Thomas Bund Andreas 《Journal of Materials Science》2021,56(20):11866-11880
Journal of Materials Science - Photoelectrochemical (PEC) water splitting can be an efficient and economically feasible alternative for hydrogen production if easily processed photoelectrodes made... 相似文献
98.
de Souza Fabrício R. Duarte-Figueiredo Fátima Gouvêa Meireles Magali R. 《Telecommunication Systems》2020,74(4):451-465
Telecommunication Systems - An efficient and fair packet scheduler is very important to guaranty the cellular network quality of service (QoS). In general, classic packet schedulers follow static... 相似文献
99.
Daisy Y. Shu Erik R. Butcher Magali Saint-Geniez 《International journal of molecular sciences》2021,22(9)
PGC-1α, a key orchestrator of mitochondrial metabolism, plays a crucial role in governing the energetically demanding needs of retinal pigment epithelial cells (RPE). We previously showed that silencing PGC-1α induced RPE to undergo an epithelial-mesenchymal-transition (EMT). Here, we show that induction of EMT in RPE using transforming growth factor-beta 2 (TGFβ2) suppressed PGC-1α expression. Correspondingly, TGFβ2 induced defects in mitochondrial network integrity with increased sphericity and fragmentation. TGFβ2 reduced expression of genes regulating mitochondrial dynamics, reduced citrate synthase activity and intracellular ATP content. High-resolution respirometry showed that TGFβ2 reduced mitochondrial OXPHOS levels consistent with reduced expression of NDUFB5. The reduced mitochondrial respiration was associated with a compensatory increase in glycolytic reserve, glucose uptake and gene expression of glycolytic enzymes (PFKFB3, PKM2, LDHA). Treatment with ZLN005, a selective small molecule activator of PGC-1α, blocked TGFβ2-induced upregulation of mesenchymal genes (αSMA, Snai1, CTGF, COL1A1) and TGFβ2-induced migration using the scratch wound assay. Our data show that EMT is accompanied by mitochondrial dysfunction and a metabolic shift towards reduced OXPHOS and increased glycolysis that may be driven by PGC-1α suppression. ZLN005 effectively blocks EMT in RPE and thus serves as a novel therapeutic avenue for treatment of subretinal fibrosis. 相似文献
100.
Organogel-Based Emulsion Systems,Micro-Structural Features and Impact on In Vitro Digestion 总被引:2,自引:0,他引:2
Nicola Duffy Han C. G. Blonk Christiaan M. Beindorff Magali Cazade Arjen Bot Guus S. M. J. E. Duchateau 《Journal of the American Oil Chemists' Society》2009,86(8):733-741
Organogels based on edible oils and specific mixtures of phytosterols can serve as structured systems with a low saturated
fat content. These low-SAFA organogels can be used also to create o/w emulsions. Little is known about the structures formed
in these specific organogels and at the emulsion interface. We studied o/w organogels on different length scales to describe
and understand their micro-structural features. Very basic processing conditions such as composition, temperature and storage
time were taken into account. Two different types of structure were observed; at the smallest scale, long thin crystals are
formed out of the oil phase into the continuous water phase. We propose that these are needle-like crystals. Next, tube-like
structures are identified and can be visualized as tubular micelles. A model is proposed which fits the dimension (~7 nm)
with the length scale of the molecular building blocks (TAGs and sterols). As edible fats from food products are enzymatically
hydrolyzed in the gut prior to absorption, we also looked into the impact on the lipase reaction speed. Simple in vitro enzymatic
hydrolysis experiments showed a slower enzymatic digestion. Organogel systems and emulsion made thereof have interesting food
structuring properties with possible advantages in composition (low SAFA) and digestion speed.
All authors were full time employees or trainee (MC) of Unilever during actual execution of this study. 相似文献