bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of trypsin by t‐Butyloxycarbonyl‐α‐aza‐(4‐aminophenyl)alanine phenyl ester
Authors: Din H. , Gray C. J. , Ireson J. C. , McDonald R. 
Published: July 2010

AbstractT‐Butyloxycarbonyl‐α‐aza‐(4‐aminophenyl)alanine phenyl ester (Fig. 1, III: R = NH2) has been synthesized. The rate of inhibition of trypsin (EC 3.4.21.4) by this compound (due to acylation followed by slower deacylation) shows a marked pH maximum at approximately 6. The shape of the pH—rate curve is discussed in terms of (i) the normal pH—activity curve of trypsin reacting with a charged substrate, i.e. the protonated form of the amino compound, (ii) the deprotonation of the 4‐amino group with pKa 4·3, and (iii) the lower rate of reaction of the enzyme with the uncharged, deprotonated form of the ester.
Dry anaerobic batch digestion of the organic fraction of municipal solid waste
Authors: Brummeler E. Ten , Horbach H. C. J. M. , Koster I. W. 
Published: July 2010

AbstractAnaerobic digestion at high solid concentrations (dry anaerobic digestion) is an attractive method for the stabilization of solid organic wastes. A new concept for dry anaerobic batch digestion (BIOCEL) of the organic fraction of municipal solid waste is presented. The start up of a BIOCEL reactor was studied with several methods of process set up and operation. Dry anaerobic digestion of the pure undiluted organic fraction obtained from a shredding/separation process was not accelerated by partial spatial separation of substrate and methanogenic inoculum (granular sludge) or leachate recycle, or both. With these three methods after 30 days the high organic acids concentration and low pH in the reactor indicated a sour reactor, unable to establish significant methane production.When the organic fraction was digested in combination with compost addition (40% (w/w) of the initial solids) and leachate recycle, the stabilization rate increased significantly. Leachate recycling in combination with partial spatial separation of the substrate/compost mixture and the inoculum showed the shortest lag phase in the methane production and the shortest digestion time. When the digested residue of a completed digestion was applied as the methanogenic inoculum (40% (w/w) of the initial total solids) the digestion time was slightly shorter. It is concluded that dilution with compost had a positive effect on the start up of the dry anaerobic digestion and compensated for a suboptimal amount of initial methanogenic biomass. During the start up of dry anaerobic batch digestion of municipal solid waste the rapid recovery of methane formation from an initial overloading was observed and was found to be the result of a population shift in the methanogenic biomass and the existence of zones in the reactor with more optimal conditions (higher p H, lower organic acids concentration). The observed digestion time was 36 days. Recommendations are given to shorten the period needed, for complete digestion.
Hydroconversion of n‐heptane on platinum/H‐Mordenite catalysts prepared via different routes
Authors: Aboul‐Gheit Ahmed K. , Menoufy Mohammed F. , El‐Morsi Akila K. 
Published: July 2010

AbstractTwo Pt/H‐mordenite catalysts were prepared via different routes: (a) by impregnating H2PtCl6 in H‐mordenite (HM) (catalyst 1) and (b) in NH4HM (catalyst II), followed by drying, calcination and reduction. Catalyst I was found (i) to be more active for n‐heptane hydroconversion, (ii) to be more selective for its isomerisation, (iii) to encounter more diffusion limitation as it yields a larger Thiele modulus, (iv) to give a lower effectiveness factor and (v) to give lower activation energy, Ea, values than catalyst II. A study of the pressure effect between 1·5 and 5·5 MNm−2 showed an increase of the catalytic activities to a maximum at 3·0 MNm−2, followed by a decrease. A compensation effect plot gave a linear relationship between In A (pre‐exponential factor in the Arrhenius equation) and Ea at various pressures for n‐heptane hydroconversion and its hydrocracking. High selectivities for central hydrocracking of heptane components and high iso‐butane to n‐butane ratios were obtained on both catalysts.
Comparative cost of colour removal from textile effluents using natural adsorbents
Authors: Nassar Mamdouh M. , El‐Geundi Mohammad S. 
Published: July 2010

AbstractA number of low‐cost materials (natural clay, bagasse pith and maize cob) have been used as adsorbents for dyestuffs (Astrazon Blue, Maxilon Red and Telon Blue) in aqueous solutions. The adsorption capacity for each dye‐adsorbent system has been determined. The relative costs of dye removal were reported based on adsorption capacity only. The following results were found. First, the relative cost of the removal of Astrazon Blue using natural clay, bagasse pith and maize cob was found to be only 1·7%, 3·9% and 4·1% that of carbon respectively. Second, the relative cost of the removal of Maxilon Red using natural clay, maize cob and bagasse pith was found to be only 2·4%, 8·3% and 10·3% that of carbon respectively. Last, the relative cost of the removal of Telon Blue using maize cob, natural clay and bagasse pith was found to be only 2·9%, 3·0% and 5·2% that of carbon respectively.
A low cost adsorbent from spent bleaching earth. I—the selection of an activation procedure
Authors: Pollard Simon J. T. , Sollars Christopher J. , Perry Roger 
Published: July 2010

AbstractThe conversion of a spent filter cake from the edible oil industry to a heterogeneous clay‐carbon adsorbent is reported. Chemical and physical activation procedures have been applied and the resulting materials screened by carbon content and aqueous phenol uptake. Full adsorption isotherms are plotted for sorbents with high phenol capacities and their adsorptive behaviour is modelled to the Freundlich and Langmuir isotherms.
Fluorescent whitening agents in heavy duty liquid detergents
Authors: Lee Frank 
Published: July 2010

AbstractFluorescent whitening agents (FWAs) for laundry detergents have been known and successfully used for decades to provide a valuable contribution to the washing results. The increased sophistication of detergent formulations, which is expected to continue into the 1990s, presents new needs and challenges for the FWA.This paper looks specifically at the development of the heavy duty liquid detergent segment and its influence on FWA formulation and performance characteristics such as processability, compatibility, stability and spotting.
Effective laundry products leading to lower chemical usage
Authors: Hepworth Paul 
Published: July 2010

AbstractLaundry washing consumes and releases into the sewage treatment system large amounts of chemicals such as phosphate builders, surfactants and alkalis. By presenting the builders and surfactants in a more instantly usable form, considerable reductions in total chemical requirements can be achieved. Nonaqueous laundry liquids described here offer a 50 to 130% reduction in chemicals entering the sewage treatment system.
Prediction of the fate of detergent chemicals during sewage treatment
Authors: Birch Ronald R. 
Published: July 2010

AbstractConsideration of a conventional growth model for the activated sludge sewage treatment process has resulted in the development of an improved method for assessing the biodegradability of chemicals. The model indicates the importance of sludge retention time (SRT) and temperature on the treatment efficiency and suggests a need to control and examine the effect of both parameters on the biodegradation of materials.The effect of SRT and temperature is illustrated by data for the nutrification of ammonia and the biodegradation of alcohol‐ and alkylphenol‐ethoxylates, LAS and nitrilotriacetic acid. The results illustrate the predictive power of the technique in obtaining results in the laboratory which are consistent with data reported from studies involving full scale treatment plants.
Reactions of oxygen and toluene in an electrical discharge reactor
Authors: Eriksson Karl R. , Brooks Brian W. , Glover John 
Published: July 2010

AbstractGaseous mixtures of oxygen and toluene have been passed through a 50 Hz electrical discharge reactor at low pressure. Oxidation reactions produced benzaldehyde, benzene, benzyl alcohol and cresols. Reaction rates varied with partial pressure of reactants, electrical field strength and temperature, although, in the absence of an electrical discharge the thermal reaction was negligible. A fit to experimental data was obtained with an equation which included reactant concentrations, temperature and applied voltage.
Study on the kinetics of hazardous pollutants adsorption and desorption by biomass: Mechanistic considerations
Authors: Tsezos Marios , Wang X. 
Published: July 2010

AbstractThe kinetics of biosorption and desorption of lindane, diazinon and 2‐chlorobiphenyl by inactive activated sludge and Rhizopus arrhizus biomass was studied. The effects of solution initial concentration, temperature and type of biomass on the observed biosorption and desorption rates were also examined. The results of the present work show that the biosorption rates are reasonably rapid, with equilibrium attained within 4 h by activated sludge and 1 h by R. arrhizus. The observed biosorption kinetics consist of a rapid initial stage followed by a slower second stage. The observed rate of organic pollutants biosorption by activated sludge during the first stage can be described by second order kinetics. The biosorption of lindane by both biomass types is reversible and the desorption process is rapid and could be described by zero order kinetics when activated sludge is used as adsorbent. The type of biomass can have a significant effect on the observed biosorption and desorption rates.
Isolation of σ‐(L‐α‐aminoadipyl)‐L‐cysteinyl‐D‐valine from culture broths by covalent chromatography
Authors: Orford Colin D. , Adlard Maxwell W. , Perry David 
Published: July 2010

AbstractAn efficient procedure for the isolation of reduced ‐(L‐α‐aminoadipyl)‐L‐cysteinyl‐D‐valine (ACV) from culture supernatants of β‐lactam antibiotic‐producing microorganisms is described. The method utilises covalent chromatography to isolate thiols from culture broths that have been deproteinised and undergone borohydride reduction. 2‐Pyridyl disulphide activated thiopropyl Sepharose was employed batchwise to isolate the thiols present in such broths from cultures of the known ACV excreter Cephalosporium acremonium N2 and the penicillin producer Penicillium chrysogenum P2. ACV was separated from these mixtures of thiols by gel permeation chromatograhy. Reversed‐phase HPLC analysis showed the ACV to be of a high purity unless isolated from a highly complex culture medium.
A methanol fuel cell having a molybdenum‐modified platinum—SPE membrane electrode
Authors: Nakajima Hiroshi 
Published: July 2010

AbstractA direct methanol fuel cell was constructed by employing a platinum—solid polymer electrolyte composite (Pt—SPE). It was confirmed, by using the cell, that adsorption of molybdenum species on Pt enhances catalytic activity for methanol oxidation both at Pt and Pt—SPE electrodes. The molybdenum treatment increased the cell voltage by 100–200 mV at a current density lower than 2 mA per apparent unit area. Methanol permeated through the SPE membrane and reduced stability of the fuel cell.
Immobilization of Desulfovibrio vulgaris cells with hydrogenase activity
Authors: Barreto M. C. , Cabral J. M. S. 
Published: July 2010

AbstractDesulfovibrio vulgaris intact cells immobilized in calcium alginate retained 45% of the hydrogenase activity of free cells. Cell immobilization had no effect on the optimum temperature for the hydrogen uptake rate, whereas the pH optimum was shifted to a higher value. The immobilization conferred on the cells a protection both against oxygen inhibition and thermal denaturation of the hydrogenase system.
Whither Zinc?
Authors: Hopkin W. 
Published: July 2010

AbstractPresent technology for production of primary zinc by the Imperial Smelting and electrolytic zinc processes followed long and expensive process development, driven by the need to improve on inefficient, small scale and labour intensive retorting processes. These newer processes are complementary, very efficient and continue to develop to meet evolving needs, with no sign of a shortage of suitable concentrates to force major change to newer technology.Several proposed intensive zinc processes to treat calcines, and an innovative direct process treating polymetallic sulphide concentrates, all need to condense bulk metallic zinc from a dust‐ or fume‐laden gas, e.g. by absorption in a lead or zinc condenser. Efficient metal recovery and process control will meet major engineering and operating difficulties. Successful commercialisation to bulk zinc, if ever achieved, will require long and expensive development, and present need does not justify the costs and effort involved.Whither zinc? Most likely down an evolutionary path from present technology, with added environmental protection whose costs must be carried by the industry, then by society.
The use of lipase (acetone powder) from Vernonia galamensis in the fatty acid analysis of seed oils
Authors: Afolabi Oladapo A. , Ologunde M. O. , Anderson Winston A. , Read John S. , Dacosta Michelle D. , Epps Flavia A. , Ayorinde Folahan O. 
Published: July 2010

AbstractExamined in this study is a potential application of Vernonia galamensis lipase (acetone powder) in enzyme‐catalyzed hydrolysis of seed oils, most especially of those containing reactive functionalities which are easily affected under drastic hydrolytic and methylating/transesterification conditions during fatty acid analysis.Eight seed oils from V. galamensis, Ximenia kaffra, castor, corn, soyabean, palm kernel, sunflower and olive were hydrolyzed by lipase (acetone powder) followed by methylation using diazomethane in ethyl ether. Results obtained showed that the lipolytic hydrolysis of triglycerides by V. galamensis lipase (acetone powder) was probably nonspecific and did not result in isomerization and as such hydrolyzed the triglycerides of the seed oil in a fashion that the resulting fatty acids were unaltered during hydrolysis. The fatty acids obtained were representative of the parent seed oils. Values reported for the various seed oils were similar to those of previous studies.
Sorption of cadmium and lead ions on modified groundnut (Arachis hypogea) husks
Authors: Okieimen Felix E. , Okundia Esther U. , Ogbeifun David E. 
Published: July 2010

AbstractThe removal of cadmium and lead ions from aqueous solutions by groundnut husks modified by reaction with EDTA (% N = 12.05) was examined by equilibrium sorption studies at 29°C. The maximum metal ion binding capacity of the EDTA‐modified husk determined from the sorption isotherm from solutions of pH 6.8 was found to be 0.36 mmol g−1 and 0.19 mmol g−1 for Cd(II) and Pb(II) ions, respectively. It was found that the rate of sorption was particle‐diffusion controlled, and the particle‐diffusion control rate coefficient was determined to be of the order of 10−2 min−1.
Characterization of cellulase and xylanase activities of Clostridium celerecrescens
Authors: Palop M. Llanos , Vallés Salvador , Piñaga Francisco , Flors Agustí 
Published: July 2010

AbstractThe production of cellulases and xylanase by Clostridium celerecrescens, a new anaerobic mesophilic cellulolytic bacterium, was studied using various substrates (cellobiose, xylan and cellulose Whatman CF‐11). While both cellulase (β‐1,4‐D‐glucan glucanohydrolase) and xylanase (β‐1,4‐xylan xylanohydrolase) were produced on cellulose, only the latter was produced when xylan was used as the sole carbon source. A weak p‐nitrophenyl‐β‐D cellobiohydrolase activity was detected in the extracellular filtrates when using cellulose as a substrate. Otherwise, β‐glucosidase (p‐nitrophenyl‐β‐D‐glucopyranosidase) was always found to be associated with the bacteria and reached its maximum levels of growth on cellobiose. In all cases, enzyme production showed a cell growth associated profile. Activities of these enzymes had their optimal values within the ranges of temperature and pH reported for the corresponding enzymes from similar anaerobic mesophilic microorganisms, although a relatively high optimum temperature, 55°C, was found for xylanase. All enzymes showed a 90% reduction of half‐life time for each 8°C increment of temperature. A 50% inhibition of xylanase and β‐cellobiohydrolase activity was observed, through a competitive mechanism, by xylose (0.677 mmol dm−3) and cellobiose (28 mmol dm−3) respectively.
Hydrogenation of phenol to cyclohexanone over Pd/MgO
Authors: Galvagno S. , Donato A. , Neri G. , Pietropaolo R. 
Published: July 2010

AbstractHydrogenation of phenol to cyclohexanone has been investigated in the temperature range 160–250°C on a series of Pd/MgO catalysts. At 160°C the orders of reaction were found on all catalysts to be about −1 with respect to phenol and about + 1 with respect to hydrogen. On the basis of the kinetic results it is suggested that the rate determining step is the surface reaction between phenol and hydrogen adsorbed on the catalyst. An increase in the reaction temperature decreases the rate of reaction. This has been explained through a change of the orders of reaction which increase with temperature. Palladium dispersion does not influence the reaction mechanism. The specific activity was found to be independent of palladium particle size.
Polarographic reduction mechanism and quantum chemical calculations of some α‐arylhydrazononitriles
Authors: Ismail M. I. 
Published: July 2010

AbstractThe polarographic reduction of 2‐arylhydrazono‐3‐keto‐3‐phenylpropionitriles (Ia–i) and 2‐arylhydrazono‐3‐ketobutyronitriles (IIa–i) over a wide pH range is reported and discussed. The mechanism of the electrode process is elucidated and confirmed via coulometric analysis, quantum chemical calculations and IR spectra of the electrolysis products. The molecular structures and molecular orbital energies were calculated and correlated with the redox potentials of these compounds.
1‐Amino‐4‐hydroxyanthraquinone‐β‐ethers and thioethers: Red dyes for synthetic‐polymer fibres
Authors: Peters Arnold T. 
Published: July 2010

AbstractCondensation of 1‐amino‐2‐bromo‐4‐hydroxyanthraquinone and of 1‐amino‐3‐bromo‐4‐hydroxyanthraquinone with alcohols, phenols and thiols yields the corresponding β‐ethers and thioethers. These compounds colour polyester in deep rose‐red to violet‐red hues of excellent build‐up and good fastness to light and sublimation. The colour of the dyes is discussed with respect to the nature and orientation of the β‐substituents.
Solubilities and diffusivities of N2O and CO2 in aqueous sulfolane solutions
Authors: Wang Yi‐Wei , Otto Frederick D. , Mather Alan E. , Xu Shuo 
Published: July 2010

AbstractThe solubilities of N2O and CO2 in aqueous sulfolane solutions and pure sulfolane solvent, and the diffusivities of N2O in aqueous sulfolane solutions were measured and correlated over the temperature range from 20° to 85°C; also, the data for density and viscosity that were needed in this experimental work were measured. This experiment revealed that the parameter of N2O analogy method depends not only on the temperature, but also on the character of the solvent. Therefore, different solvents possess different analogy parameters. Only for dilute aqueous solutions can the parameter be replaced by the analogy parameter of water. The results also proved that the sum of volume fractions contribution is a simple method to estimate the solubility in aqueous sulfolane solutions over the whole range of the concentrations and experimental temperatures, with an average deviation of less than 4·0%.
Starch hydrolysis kinetics of Bacillus licheniformis α‐amylase
Authors: Komolprasert Vanee , Ofoli Robert Y. 
Published: July 2010

AbstractThe reaction kinetics for thermostable Bacillus licheniformis α‐amylase was determined under two sets of conditions: an initial rate study over a range of low starch concentrations (1–8%, w/w) in a batch reactor, and a continuous rate study at a high starch concentration of 40% during which a twin‐screw extruder was used as a bioreactor for the first 600 s and the reaction was continued to equilibrium in a batch reactor. The Michaelis–Menten model was found to be sufficient for describing the kinetics at low starch concentrations; however, a modified first‐order model was required at high concentration. There was no evidence of substrate inhibition at the high starch concentration. The rate of product formation, calculated in terms of dextrose equivalent (DE) values, was found to be proportional to the square root of the rate of starch consumption.
Model dyes for optimizing the dyeing of polyamide
Authors: Savarino Piero , Viscardi Guido , Carpignano Rosarina , Barni Ermanno 
Published: July 2010

AbstractModel disperse azo dyes, containing a salicylic moiety, hydrophobic alkyl chains and usual substituents, allowed the investigation of the effects of these structural variations on dyeing properties.By combining the results of both equilibrium and rate studies, some interesting structures for practical purposes could be identified.
Aminopropylsilane treatment for the surface of porous glasses suitable for enzyme immobilisation
Authors: Janowski Frank , Fischer Gunter , Urbaniak Wlodzimierz , Foltynowicz Zenon , Marciniec Bogdan 
Published: July 2010

AbstractDuring silylation of porous glass with 3‐aminopropyltriethoxysilane, the properties of the carrier affected the concentration of bound amino groups, the formation of aminopolysiloxane mono‐ or multilayer on the surface, and the hydrolytic stability of the layer formed. The influence of the carrier depended on the specific surface area and the size of pores.In contrast to silylation performed in organic solvents, in aqueous solutions a monolayer of aminopolysiloxane of high hydrolytic stability was formed on the surface of porous glass. Tetraethoxysilane modification of porous glass prior to silylation with aminosilane yields carriers of increased hydrolytic stability. Glucoamylase immobilised on carriers, that were modified in aqueous solutions, exhibit higher enzymatic activity.
Interfacial activity of N‐8‐quinolyl‐p‐dodecylbenzenesulphonamide and the interfacial mechanism of copper extraction
Authors: Szymanowski Jan , Jakubiak Artur , Alejski Krzysztof 
Published: July 2010

AbstractVarious adsorption isotherms were matched to the interfacial tension data in the N‐8‐quinolyl‐p‐dodecylbenzenesulphonamide‐toluene‐water system and used to compute the surface excess isotherms and to predict the reaction orders with respect to extractant for various versions of the interfacial mechanism of copper extraction. Comparison of these reaction orders with those determined experimentally shows that the reaction rate can be limited by the formation of the stable 2:1 complex in the reaction of intermediate 1:1 complex with the sulphonamide molecule both adsorbed at the interface and present in the aqueous film near the interface.
Kinetics and mechanism of Yttrium extraction with three acidic phosphorus extractants
Authors: Ma Enxin , Jiang Peihua , Jin Pinli 
Published: July 2010

AbstractA mechanic study is reported, which deal with the kinetic aspects of yttrium extraction from HAc‐NaAc‐EDTA media, using three acidic phosphorus extractants (HL), di(2‐ethylhexyl)phosphoric acid (HDEHP), 2‐ethylhexylphosphonic acid mono‐2‐ethylhexyl ester (HEH[EHP]) and di(2,2,4‐trimethylpentyl)phosphinic acid(H[DTMPP]) in n‐octane solution. The initial rates of extraction for these three systems were determined under conditions of energetic stirring or mixing of the two phases. The rate data were correlated as a function of the concentration of the relevant species. From the rate equations magnified image and the interfacial characteristics, the heterogeneous chemical reaction magnified image was established as the rate‐determining step of the overall reaction for the three extractants studied. A mechanism has been proposed for this reaction. The order of the extraction rate was found to be HDEHP>HEH[EHP] > H[DTMPP], and is related to the number of CP bonds in the extractants.