bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoselective effect of kynurenine enantiomers on the excretion of serotonin and its metabolite in rat urine
Authors: Sasaki Tsukasa , Fukushima Takeshi , Yamashita Kazuhide , Toyo'oka Toshimasa 
Published: June 2009

AbstractA solution of optically pure kynurenine (KYN), i.e., D‐KYN or L‐KYN, was administered intravenously to male Sprague‐Dawley rats (10 mg kg−1 ml−1). The time‐course of changes in the concentrations of urinary monoamines and their metabolites such as 5‐hydroxytryptamine (5‐HT), 5‐hydroxyindole acetic acid (5‐HIAA), dopamine, and 3‐methoxytyramine were investigated by reversed‐phase high‐performance liquid chromatography with electrochemical detection after precolumn derivatization with (2R)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (NPCA). We observed a stereoselective difference in the effects of the KYN enantiomers. Only D‐KYN, not L‐KYN, caused a significant increase in urinary 5‐HT levels within 30 min after its administration. With regard to the metabolites, urinary 3‐MT level was increased by D‐KYN administration. On the other hand, no significant change in the DA level was observed after administration of either D‐KYN or L‐KYN. These results suggest that D‐KYN could affect the activity of neuroactive amines, especially 5‐HT, in vivo. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Stereoselective plasma protein binding of amlodipine
Authors: Maddi Srinivas , Yamsani Madhusudan Rao , Seeling Andreas , Scriba Gerhard K. E. 
Published: June 2009

AbstractThe binding of the (R)‐ and (S)‐enantiomers of amlodipine to bovine serum albumin (BSA), human serum albumin (HSA), α1‐acid glycoprotein (AGP), and human plasma (HP) was studied by equilibrium dialysis over the concentration range of 75–200 μM at a protein concentration of 150 μM. Unbound drug concentrations were determined by enantioselective capillary electrophoresis using 50 mM phosphate buffer, pH 2.5, containing 18 mM α‐cyclodextrin as background electrolyte. Saturation of the protein binding sites was not observed over the concentration range tested. Upon application of racemic amlodipine besylate, (S)‐amlodipine was bound to a higher extend by HSA and HP compared with (R)‐amlodipine, whereas the opposite binding of the enantiomers was observed for BSA and AGP. Scatchard analysis was used to illustrate the different binding affinities of amlodipine besylate enantiomers to BSA, HSA and AGP. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Effect of bile and lipids on the stereoselective metabolism of halofantrine by rat everted‐intestinal sacs
Authors: Patel Jigar P. , Korashy Hesham M. , El‐Kadi Ayman O.S. , Brocks Dion R. 
Published: June 2009

AbstractThe everted rat intestinal‐sac model was utilized to assess the effect of post‐prandial conditions on the stereoselective intestinal metabolism of halofantrine to its active metabolite desbutylhalofantrine. Everted intestinal sacs were incubated with (±)‐halofantrine HCl in the presence of simulated bile solution (containing lecithin, lipase and cholesterol) and lipids to mimic post‐prandial conditions in the small intestine. The halofantrine enantiomer concentrations in intestinal sacs were relatively constant in the presence of bile, but decreased significantly on addition of lipids to the incubation media. Formation of desbutylhalofantrine enantiomers was inversely proportional to bile concentration whereas addition of lipids in the presence of bile caused a significant decrease in desbutylhalofantrine:halofantrine ratio of (−) enantiomers. Pre‐treatment of rats with peanut oil had no significant effect on desbutylhalofantrine formation in the incubated sacs or microsomal preparations, nor did it affect the expression of intestinal cytochrome P450. Addition of extra cholesterol to the bile incubations caused a significant increase in tissue halofantrine and desbutylhalofantrine concentrations, which as for lower cholesterol, were diminished on addition of other lipids. The results were consistent with previous in vivo evaluations showing that the desbutylhalofantrine to halofantrine ratio was decreased by the ingestion of a high fat meal. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Produktdesign disperser Stoffe: Industrielle Sprühtrocknung
Authors: Rähse W. , Dicoi O. 
Published: June 2009

AbstractDie in Sprühtürmen durchgeführte Zerstäubungstrocknung stellt das Standardverfahren zur Herstellung von Pulvern aus Flüssigkeiten (Lösungen, Suspensionen, Emulsionen) dar. Dieser an sich einfache Prozess bietet viele Parameter zur Optimierung. So werden in der Industrie auch bei etablierten Verfahren Leistungssteigerungen, Energieverbräuche, Produktqualitäten, Anlagensicherheit und Abluft regelmäßig diskutiert. Leistungssteigerungen lassen sich über den Einsatz von deutlich mehr Düsen, die entsprechend kleiner sind, erreichen. Die dann mögliche, erhöhte Menge an gesprühter Flüssigkeit pro m3 Gas/h senkt den spezifischen Energieverbrauch. Das Partikeldesign (Form, Schüttgewicht, Rieselfähigkeit) wird über die stoffabhängige Strukturbildung während des Trocknungsvorganges bestimmt. In Abhängigkeit von den Stoffeigenschaften und vom Feststoffgehalt ist die getrocknete Partikel größer oder kleiner als der gesprühte Tropfen. Im Vergleich zu den Tropfengrößen weisen die am Turmkonus ausgetragenen Produkte infolge von Agglomerationen deutlich höhere Werte für die Partikeldurchmesser auf. Zum sicheren Betreiben des Zerstäubungsturms müssen Zündquellen vermieden werden. Viele organisch basierte Rezepturen erfordern das Arbeiten unter Stickstoff. Eine interessante Alternative stellt die Trocknung mit überhitztem Wasserdampf dar, weil kein Abgas entsteht und sich die Energie weitgehend zurückgewinnen lässt. Das übliche Scale‐up vom Labor über das Technikum in die Produktion ist nicht möglich. Die Vorgehensweise über die Auswahl der Düsen wird beschrieben.
Adsorption and flotation studies with quartz: Part I. Adsorption of calcium, hydrogen and hydroxyl ions on quartz
Authors: Ahmed S. M. , Van Cleave A. B. 
Published: June 2009

AbstractThe adsorption of calcium ions from aqueous solutions on − 65 + 200 mesh quartz has been measured using Ca45 as a tracer. Results are given for initial Ca++ ion concentrations of (4.2 to 11.5) × 10−4 gm. ions/liter over the pH range 4 to 12. Changes in pH occurring during the adsorption have also been determined. The mechanisms of cationic adsorption on quartz in aqueous media, and the activation of quartz surfaces for flotation with anionic collectors are critically discussed.
Adsorption and flotation studies with quartz: Part II. The adsorption of laurate and myristate on quartz
Authors: Ahmed S. M. , Van Cleave A. B. 
Published: June 2009

AbstractThe adsorption of laurate and myristate ions on quartz from solutions containing (1 to 25) × 10−5 gm. ions/liter of adsorbate at different pH values, both in the absence and in the presence of Ca++ ions, has been measured using C14‐labelled compounds as tracers. The results have been correlated with the flotation behavior of quartz as determined by Hallimond tube and bubble pick up techniques.
Chemical and physical limits on vapor‐phase diffusion flames of droplets
Authors: Brzustowski T. A. 
Published: June 2009

AbstractThe combustion of a fuel droplet can be described by a quasi‐steady theory at pressures up to about 1/10 of the critical pressure of the fuel. Finite rates of chemical reaction and evaporation impose lower bounds on the product of pressure and droplet size for which the theory is valid. An unsteady droplet theory becomes necessary for pressures between the highest pressure for a quasi‐steady theory and the critical pressure.Unsteady heat transfer and diffusion of dense gas are the significant processes in the combustion of a liquid fuel above its critical pressure. The burning rates above the critical pressure are likely of the same order as at lower pressures.
The influence of surfactants on mass transfer around spheres
Authors: Lochiel A. C. 
Published: June 2009

AbstractEquations are derived to predict the effect of trace surface‐active impurities on mass transfer across a spherical interface.Transfer in the bulk phase surrounding spheres with both rapid and slow internal circulation, and moving in creeping flow, is shown to decrease on increasing the surfactant concentration.Drag and transfer equations for contaminated rapidly‐circulating spheres moving at high Reynolds numbers are in semi‐quantitative agreement with published data.The influence of surface‐active contaminants on drag and transfer decreases as the viscosity of the bulk phase is increased.
Some further observations on tubular reactor stability
Authors: Amundson Neal R. 
Published: June 2009

AbstractA necessary and sufficient condition for stability of the empty adiabatic tubular reactor with axial mixing is derived which depends upon steady state information alone. The stability conditions require the solution of a linear ordinary differential equation and the character of this solution determines the stability or instability of the system without the use of transient calculation. The lumped constant reactor is always stable. The method of computation requires a minimum amount of memory capacity in a digital computer and could be carried out on an analogue computer with ease.
A kinetic study of the regeneration of a dehydrogenation catalyst
Authors: Mickley Harold S. , Nestor John W. , Gould Leonard A. 
Published: June 2009

AbstractExperimental measurements were made of the rate at which coke, deposited in situ, was burned off a porous chromia‐alumina dehydrogenation catalyst by hot air. Over the range of variables examined, the regeneration rate passed from complete dependence on chemical kinetics to complete dependence on the rate of oxygen diffusion through the catalyst pores. A model of the regeneration process which accounts for simultaneous pore diffusion and chemical kinetics was successfully fitted to the experimental data.
The turbulent flow characteristics of model fibre suspensions
Authors: Bobkowicz A. J. , Gauvin W. H. 
Published: June 2009

AbstractThe pressure drop of aqueous model nylon fibre suspensions was determined in a vertical 2‐in. copper tube in the turbulent range as a function of velocity, fibre length‐to‐diameter ratio (L/D) and concentration. Fibre diameters ranged from 20.2 to 51.6 microns and length from 0.52 to 1.21 mm. A marked depression below the value for the pressure drop of water was observed at high L/D's and its magnitude increased with the solids concentration. For low L/D values the depression was almost negligible. An explanation is advanced for the depression in pressure drop based on alterations in the turbulence characteristics in the presence of fibres.
Calcination of fluid coke in an electrically heated fluidized bed
Authors: Paquet J. L. , Foulkes P. B. 
Published: June 2009

AbstractLaboratory studies carried out by Alcan showed that fluid coke, being of consistent uniform spherical size, could easily be fluidized, with the fluidized bed being able to carry an electrical current. This discovery led Alcan people to the conclusion that electric calcination in a fluidized bed would be a most favorable method for calcining fluid coke.It is the purpose of this paper to outline the main features of a one‐ton per hour pilot unit which was built to study this new calcination technique, and in particular to focus attention on the numerous problems that had to be solved before obtaining a successful operating unit.
The flow of suspensions through tubes IV: Oscillatory flow of rigid spheres
Authors: Shizgal B. , Mason S. G. , Goldsmith H. L. 
Published: June 2009

AbstractThe theory of oscillatory flow of a homogeneous liquid in a straight circular tube developed by Lambossy and Womersley has been confirmed by direct measurements of the displacement profiles for a sinusoidal pressure gradient at various frequencies.Rigid spheres suspended in the liquid showed radial migration away from the walls and away from the tube axis when the particle Reynolds number was made sufficiently high. This is the analogue of the tubular pinch effect discovered by Segré and Silberberg for steady flow, and is also exhibited by concentrated suspensions.The modification of the flow behavior of suspensions by Miperposition of an oscillatory pressure is briefly discussed.
Old and new problems in the field of vapor‐liquid equilibria
Authors: Redlich Otto 
Published: June 2009

AbstractThe present survey elaborates some of the topics discussed in an address presented at the 13th Canadian Chemical Engineering Conference in Montreal, October 23, 1963. Such a survey, of course, can mention only few of the important contributions of various authors that have elucidated the field of vapor‐liquid equilibria in the last twenty years.Thermodynamic consistency is only briefly mentioned. Since activity and fugacity coefficients are used for quite different purposes it is better to define them differently without trying to maintain a formal analogy. Activity coefficients of non‐associating mixtures are satisfactorily represented by the traditional two‐parameter relations. For associated solutions, as a rule, an association function must be superimposed. Further development and testing of association terms is desirable. Progress in the systematic representation of interaction in solution is promising. Calorimetric measurements in recent years have made considerable contributions.
Saturated vapor and liquid densities of pure substances
Authors: Barile Ronald G. , Thodos George 
Published: June 2009

AbstractRelationships between zR and PR have been developed for the prediction of the complete saturated vapor and liquid density curves of pure substances. The coefficients and exponents of these relationships were derived from the saturated densities of 23 polar and nonpolar substances and were found to depend on zc, the critical compressibility factor of each of these substances. Densities calculated with these relationships produced average deviations of 1.5% for the saturated vapor region and 2.7% for the saturated liquid region from 54 points considered for each substance.
Experimental determination of circulation velocities inside drops
Authors: Horton T. J. , Fritsch T. R. , Kintner R. C. 
Published: June 2009

AbstractVelocities inside large drops suspended in a fluid flowing upward in a tapered glass tube were measured by darkfield particle trace photography. Drop Reynolds numbers were between 3.76 and 19. There was a slow decay of internal velocity and a change in circulatory pattern with the accumulation of minute amounts of colloidal impurities at the interface. The evidence indicates that streamlines leave the interface over the entire rear hemisphere of the drop as circulation is damped.
The electrical resistance of fluidized beds of coke and graphite
Authors: Graham W. , Harvey E. A. 
Published: June 2009

AbstractThe electrical resistance of beds of finely divided graphite and conducting coke have been investigated in the settled and fluidized regions.In almost all cases a maximum in the bed resistance occurs at a gas velocity slightly greater than that required for minimum fluidizing. This has been explained qualitatively by assuming current flow along a continuous network of touching particles the resistance of which is modified by the growth of gas bubbles in the bed.
Pressure‐volume‐temperature behaviour of ethyl alcohol in the gaseous and liquid states
Authors: Bhattacharyya Dibakar , Thodos George 
Published: June 2009

AbstractPVT data available in the literature for ethyl alcohol have been utilized for the development of a reduced density correlation for this substance. The critical constants accepted in this study are those determined by Young(1)Tc= 516.3°K, Pc= 62.96 atm, andpe= 0.276 g/cm.3. To extend the available PVT information for ethyl alcohol over the complete range of temperatures up to TR= 1.8 and pressures up to PR= 40, use has been made of the available reduced density correlation of ammonia(2)and the Nelson‐Obert compressibility factor charts(3).
Radioactive tracer experiments on large stirrers for liquid‐liquid contacting
Authors: Stemerding S. , Groothuis H. , Hoogendoorn C. J. 
Published: June 2009

AbstractThe use of radioactive tracer techniques for studying the flow through large‐scale plant reactors under operating conditions is illustrated by tests on a 530‐cu. ft. stirred vessel used for contacting a hydrocarbon and an aqueous stream. The two streams had to be traced simultaneously. Simple equations are given for calculating the phase holdup from pulse response curves.It was found that the reactor, a vessel equipped with propeller stirrer and draught tube, contained a relatively large proportion of the heavier aqueous phase which even partly formed a dead zone at the bottom, when the propeller was pumping downwards. Reversal of the pumping direction resulted in an improved operation.
The effect of changes in initial composition on the equilibria of solid‐gas systems
Authors: Storey S. H. 
Published: June 2009

AbstractA method is given for calculating the change in the equilibrium composition of a multicomponent solid‐gas system at constant temperature and pressure directly from a given change in the initial reactant composition, thus avoiding the complete recalculation of the equilibrium for each new initial mixture. The method can also be used to calculate individual equilibrium compositions. Two examples of how the calculations should be set up are given.
Kinetics of the catalytic oxidation of isobutene
Authors: Mann R. S. , Rouleau D. 
Published: June 2009

AbstractThe air oxidation of isobutene was investigated over supported and unsupported copper oxide catalysts in an isothermal integral flow reactor. The effect of various variables, that is, ratio of oxygen to isobutene in the feed, process temperature, copper concentration on the catalyst and reciprocal of space velocity on the conversion and yield were determined.Though several mechanisms were postulated, the rate of reaction was most satisfactorily correlated by a mechanism which assumes the rate controlling step as the surface reaction between strongly adsorbed isobutene and gaseous (weakly adsorbed) oxygen. A rate equation has been derived and the kinetic rate constant and adsorption constants for isobutene and methacrolein are reported as functions of temperature.
Treatment of hydrocarbon lubricating oil by sodium alloys
Authors: Sirianni A. F. , Alexander W. A. , Puddwgton I. E. 
Published: June 2009

AbstractSodium extended in the form of alloys with inert metals indicates marked acid neutralizing properties for hydrocarbon lubricating oil when the systems contain at least 20 atom percent sodium. Transparency of the treated oil correlated well with pH measurements.
Critical temperatures and pressures of the ethane–n‐heptane system
Authors: Ekiner Okan , Thodos George 
Published: June 2009

AbstractThe critical temperatures and critical pressures of the ethane—n‐heptane system have been established experimentally with a visual PVT cell which utilized mercury as the pressurizing medium. The information obtained from the relative hydrocarbon volumes of the vapor and liquid phases permitted the measurement of these critical values.Five different binary compositions were used to establish the critical temperature locus and critical pressure locus for compositions of x2 ≥ 0.655. The critical constants obtained in this study have been compared with corresponding values from the work of Kay(1).
Absorption of ethylene by aqueous chlorine solution
Authors: Akehata T. , Johnson A. I. 
Published: June 2009

AbstractA study has been made of the rates of absorption of ethylene into aqueous chlorine solutions. The results are reported graphically as enhancement factors which have been compared with the predictions of the Hatta theory and with a simple model based on slow chemical reaction and diffusion of the main reactants. At lower temperatures the proposed model provides a reasonable description of the reaction accompanied mass transfer and yielded a rate constant for the formation of ethylene chlorohydrin; at 20 °C. and above, the Hatta model is sufficient.Studies were made using solutions with increased concentrations of hydrochloric acid and hypochlorous acid and the catalytic effect of glass and gas liquid surfaces was studied.
Influence of a falling thin liquid film upon a co‐currently flowing gas stream in a vertical duct
Authors: Pike John G. 
Published: June 2009

AbstractA theoretical model of a gas stream flowing co‐currently with a liquid film is established. The model is used to analyse the experimental results obtained for the co‐current flow of an air stream and a thin water film in a vertical rectangular duct. The influences of the motion and non‐smooth nature of the film surface upon the air stream are isolated and values of equivalent sand roughness are determined.
The application of stereophotogrammetry to the measurement of interfacial waves
Authors: Charles M. E. , Lilleleht L. U. 
Published: June 2009

AbstractA stereophotogrammetric technique is described which was used to measure amplitudes and wavelengths for wave patterns generated at the interface between two liquid layers flowing co‐currently in a closed rectangular conduit. In the preliminary experiments differences in the interfacial elevation due to the presence of Waves of amplitude as low as 0.2 mm. and wavelength of 75 mm. could be detected using this technique. Stereophotogrammetry having the advantage that no probes of any kind interfere with the flowing liquids may well become another useful tool in chemical engineering research.
The pipeline flow of paste slugs: I. Concepts and general flow behavior
Authors: Berkowitz N. , Brown R. A. S. , Jensen E. J. 
Published: June 2009

AbstractCylindrical paste segments, carried by a liquid hydrocarbon (such as crude petroleum), can be transmitted through pipelines in much the same manner as rigid capsules or ingots, and the technique may therefore offer a useful method for long‐distance bulk commodity transportation.In this paper, basic concepts of paste slug conveyance are briefly discussed and a first detailed study—mainly concerned with general flow behavior and flow velocities of individual slugs in an experimental 1‐in. i.d., 70‐ft. long closed‐loop line—is reported. As a matter of convenience, attention is confined to the flow of coal paste segments (prepared from a 70:30 w/w coal‐water paste) in a refined light mineral oil (ρ = 0.829 gm./cc. and μ = 7.05 cp at 60°F.). Slug‐to‐pipe diameter ratios varied from 0.5 to 0.8, and fluid velocities ranged to 11 ft./sec. (corresponding to pipe Reynolds numbers up to ca. 12,000).
Isobaric binary vapor‐liquid equilibria system: Carbon tetrachloride‐tetrachloroethylene
Authors: Subbarao B. V. , Venkatarao C. 
Published: June 2009

AbstractVapor‐liquid equilibrium data are presented for the binary system, carbon tetrachloride‐tetrachloroethylene, at 760 ± 1 mm.Hg. total pressure using a modified Colburn equilibrium still. The system showed a tendency for ideal behavior. The experimental data have been correlated with the stepwise integration method of Othmer and with Hirata and Prahl correlations. Excellent agreement was obtained with Prahl correlation.
Reaction accompanied mass transfer between liquid phases
Authors: Seto P. , Furter W. F. , Johnson A. I. 
Published: June 2009

AbstractSimple apparatus for studying the rates of transfer of esters such as ethyl acetate and ethyl formate across a plane surface into water and into caustic solutions is described. Quantitative measurements of the rate of transfer are reported.In a semibatch operation using stirring in both phases, an unexpected retardation of the transfer of ethyl acetate into the reacting solutions was observed.To investigate the phenomenon at the interface, reaction mass transfer studies with still phases were carried out. The use of Moiré patterns for observing the formation of a turbulent reaction zone and the concentration gradients in the aqueous phase has been studied. Factors influencing the rate of propagation of the reaction zone are discussed.