bluuebunny/crossref_metadata_2025 huggingface dataset:
Zirconium‐based intermetallics as heterogeneous catalysts for the fischer‐tropsch reaction: III. Zr‐Co‐Ni‐Cu and Ru catalysts
Authors: Al‐Shammary A. F. Y. , Caga I. T. , Tata A. Y. , Winterbottom J. M. , Harris I. R.
Published: July 2010

Intermetallic alloys of the general type Zr50MxN50‐x, where 0 ≦x≧ 50, were prepared by argon arc melting of the constituent elements. M and N are combinations of cobalt, nickel, copper and ruthenium. The alloys were powdered by hydrogen decrepitation, which yielded hydrided species of the general composition Zr50MxN50‐′H150‐x′ in which form they were used as catalysts.

The reactions were carried out in a semi‐micro‐tubular flow reactor at 1 barg, 350°C and a H2/CO feed ratio of 3. It was observed that, while methane (CH4) was the dominant product, there was clear indication that intermetallic alloys containing Cu and Ru gave larger quantities of higher hydrocarbons and one alloy Zr50Ru25Co25 was 102‐103 times more active than any of the others, based on turnover number (TON) calculations; its activity was also observed to decline rapidly. The study of catalysts derived from intermetallic compounds provides a useful means of investigating alloy effects, due to the precise stoichiometry of the starting compounds which have long‐range order in respect of crystal structure. However, they can be rendered unstable by involvement with reactants, especially with oxygen.
Thermal decomposition of azobisisobutyronitrile dissolved in xylene in the presence of tin(IV) chloride
Authors: Juang Ruey‐Shin , Liang Ji‐Feng
Published: July 2010

The rate of thermal decomposition of azobisisobutyronitrile (AIBN) dissolved in xylene was investigated alone and in the presence of tin(IV) chloride over the temperature range of 90–107°C. It was found that the decomposition rate of AIBN increases linearly with increasing concentration of tin(IV) chloride, which suggests the formation of an activated complex between AIBN and tin(IV) chloride. A parallel reaction mechanism is proposed to describe the kinetic behavior. The Arrhenius relationships of rate constants were also obtained.
Uptake of benzenecarboxylate ions by magnesium aluminium oxides
Authors: Sato Tsugio , Kato Kenji , Yoshioka Toshiaki , Okuwaki Akitsugu
Published: July 2010

The behaviour of uptake of the benzenecarboxylate ions, C6H6‐n(COO)nn (n = 1–6), in aqueous solutions by rock‐salt type magnesium aluminium oxide, Mg(1‐x)(2+x)Al2x/(2+x)O (x = 0.17, 0.30, 0.33) was investigated at 0.70°C. All the benzenecarboxylate ions were taken up from solution competitively with OH‐ to form the hydrotalcite‐like layered double hydroxides. The uptake rate could be adequately described by a surface chemical reaction controlled shrinking core model, and the apparent activation energy was c. 60 kJ mol−1. The selectivity of anion uptake increased with increasing the charge density of the benzenecarboxylate ions. The amount of benzenecarboxylate ions incorporated in the interlayer of hydrotalcite and the selectivity of uptake for benzenecarboxylate possessing higher electric change increased with increasing aluminium content in the magnesium aluminium oxide.
Reduction of aqueous carbonate photocatalysed by treated semiconductors
Authors: Khalil Laila B. , Youssef Nabil S. , Rophael Magdy W. , Moawad Mona M.
Published: July 2010

Heterogeneous photocatalysed reduction of aqueous Na2CO3 solution (1 m) was achieved by using phthalocyanine‐coated semiconductor powders (1–3% coating) as well as bare semiconductors. The suspensions were irradiated with 254 nm light from a low‐pressure mercury lamp in a nitrogen atmosphere. The phthalocyanine dyes (Fe2+‐Pc or Co2+‐Pc) absorb > 80% of the 254 nm radiation and thus sensitize the semiconductor. The products of reduction (CH3OH and HCHO) were determined spectrophotometrically. The CH3OH yields obtained are much higher than the HCHO yields, due to a photocatalysed reduction of HCHO to CH3OH. The CH3OH yields from coated titania increased linearly with irradiation time over the period 6–18 h. However, the straight line does not pass through the origin, and it seems that a slowing‐down occurs at times > 6 h. Titania coated with both dyes gave an optimum CH3OH yield at 2% surface coating. At higher coating percentages, phthalocyanine screens the surface, thus reducing the light reaching the semiconductor. Changing the redox potential of the phthalocyanine dye by changing its central metal from Fe to Co affects the CH3OH yields. The bare MoS2 photocatalyst gave a much higher CH3OH yield due to the characteristic behaviour of the semiconducting layer‐type disulphide, distinguished from that of classical semiconducting materials. In the various semiconductors studied, it seems that there is no correlation between the position of the conduction band and the yield of CH3OH. Such correlation was argued. Generally, a decrease in the yield of CH3OH was observed as the band gap width of the semiconductor increased. The yields of the photoproduced CH3OH generally increased with the percentage of light absorbed at 254 nm by the various semiconductors. Irradiation leads to the production of electrons in the conduction band of the semiconductor. It is likely that the photoproduced electrons reduce CO32‐ initially to HCOO‐ and then to HCHO and CH3OH.
An examination into the structure of stable foams formed on activated sludge plants
Authors: Foot R. J. , Kocianova E. , Forster C. F. , Wilson A. J.
Published: July 2010

Although stable foams on activated sludge plants have been under discussion for about 25 years, their structure and the reasons for their structure are still unresolved. The paper describes a study, based on cryogenic electron microscopy and rheology, into foam structure. The results have shown that a foam consists of air bubbles held in a dense matrix of filamentous microbes and that the individual bubbles were surrounded by a film which contained cellular material. Rheology measurements showed that foams had an appreciable viscosity which varied with the concentration of solids in the foam. A significant difference occurred between the foam viscosities and those of non‐foaming activated sludge that had been thickened to similar concentrations of solids.
Selective extraction of metal ions through liquid surfactant membranes
Authors: Shiau Ching‐Yeh , Jung Shou‐Wen
Published: July 2010

Selective separation of metal ion from a liquid solution with the help of different permeation rate of solutes through liquid membranes was performed. The salts used were ZnCl2, CdCl2, NiCl2. D2EHPA and LIX64N were used as carrier to study the extraction rate of the solutes. The results show that at low pH value of external phase the order of degree of extraction by D2EHPA or LIX64N is Zn > Cd > Ni, while at high pH value with the presence of ammonia in the feed solution the order of degree of extraction is reversed to Ni > Cd > Zn. The results also indicate that when the mixed carrier is used an enhanced effect on the extraction was observed. Synergistic effect was also noted when comparing the cases with mixed carriers to those with pure carriers.
Production of the enzyme dihydrofolate reductase by methotrexate‐resistant bacteria isolated from soil
Authors: Nigam Poonam , Marchant Roger
Published: July 2010

Six bacterial cultures isolated from soil were capable of growing in the presence of methotrexate (MTX). Two strains, PFR‐1 and 3, developed resistance to 500 μg cm−3 MTX in the medium and produced elevated levels of the enzyme dihydrofolate reductase (EC 1.5.1.3): 2580 and 2702 U dm−3 compared to the sensitive parent strains (28 and 35 U dm−3). Isolate PFR‐3 showed maximum enzyme production (4950 U dm−3, specific activity 12.56 U mg−1 in flasks and 5737 U dm−3, specific activity 14.80 U mg−1 in 5‐dm3 fermenter) during exponential phase of growth (6 h) at 37°C and pH 7.0.
Studies on the fungicidal properties of some triphenyltin(IV) compounds
Authors: Chandra Shubhra , Gioskos Sam , James Bruce D. , Macauley Barry J. , Magee Robert J.
Published: July 2010

The results are reported for an investigation into the fungicidal properties of six triphenyltin(IV) compounds representing metal coordination numbers of four through six. These experiments were conducted against a number of soil and plant pathogenic fungi and compared with the results obtained from triphenyltin chloride. While all the compounds examined proved to be effective fungicides, differences at the concentration levels tested were not sufficiently pronounced to relate the degree of toxicity to the molecular structure.
Recovery of epichlorohydrin and dichloropropanols from waste
Authors: Milchert Eugeniusz , Goc Waldemar , Myszkowski Jerzy
Published: July 2010

A method of recovery of the organic compounds: dichloropropanols, epichlorohydrin, 1,2,3‐trichloropropane from epichlorohydrin plant waste has been performed. The method depends on the adsorption of organic compounds in the active carbon and their desorption by allyl chloride. Allyl chloride is desorbed by steam. After desorption the solutions are recirculated to the epichlorohydrin plant.
Electrosynthesis of organic compounds. XVI. Cathodic reduction of some haloalkyl naphthyl sulfides and sulfones in nonaqueous solvent
Authors: Ismail Mohamed T. , El‐Zohry Maher F.
Published: July 2010

Three aryl haloalkyl sulfur compounds—chloroethyl β‐naphthyl sulfide, chloropropyl β‐naphthyl sulfide and chloroethyl β‐naphthyl sulfone—were subjected to cathodic reduction. The compounds were cathodically electrolyzed under a controlled potential of −2.00 ± 0.03 V vs SCE on a zinc cathode as the working electrode and a platinum anode as helping electrode in absolute methanol containing Ba(ClO4)2 as supporting electrolyte at constant temperature (30°C). The isolated products were alkyl β‐naphthyl sulfides, alkyl β‐naphthyl sulfones, alkenyl β‐naphthyl sulfides, alkenyl β‐naphthyl sulfone, β‐naphthyl thiols (in case of sulfides), naphthalene and other identified products. Suitable mechanisms are suggested.
Kinetics of oxygen absorption in aqueous sodium dithionite solutions
Authors: Shaikh Abdulla A. , Zaidi S. M. Javaid
Published: July 2010

The absorption and reaction of oxygen in aqueous alkaline solutions of sodium dithionite has been experimentally investigated in a novel gas‐liquid contactor. The novel gas‐lift bubble column contactor was used to study the kinetics over wide ranges of reactant concentrations, temperature, and pH. The oxygen‐sodium dithionite reaction was found to be first‐order with respect to dithionite in the range of dithionite concentration < 0.1 M, and second‐order in the range of dithionite concentration > 0.1 M. The reaction with respect to oxygen was found to be zero‐order for all dithionite concentrations. These results and experimental investigations of the effect of solution alkalinity and temperature on the reaction rate are consistent with previous findings obtained in different gas‐liquid contactors. The results thus confirm the feasibility of using the gas‐lift bubble column for the kinetics of gas‐liquid reactions.
Kinetic study of an anaerobic fluidized bed system used for the purification of fermented olive mill wastewater
Authors: Martín A. , Borja R. , Chica A.
Published: July 2010

The anaerobic digestion of olive mill wastewater (OMW) in a fluidized bed, pretreated with Geotrichum candidum, has been studied. The bioreactor used (volume = 3.5 dm3; biomass concentration = 11.5 g VSS dm−3) maintained satisfactory operation for 4 to 35 days, in terms of hydraulic retention time, and removed 92% of the initial COD. The system was used to develop and test a kinetic model which was subsequently employed to determine growth yield and maintenance coefficient. From the results obtained, the Michaelis‐Menten equation accurately described the substrate uptake (i.e. COD removal) in the anaerobic fluidized bed system. Pretreatment of the OMW was found to increase the rate of substrate uptake by a factor of 3.2 when compared to untreated OMW.
Cyclohexanethiol separation from kerosene oil by red mud
Authors: Singh Awadhesh Pratap , Singh P. C. , Singh V. N.
Published: July 2010

The transfer of cyclohexanethiol from kerosene oil to unconventional adsorbent, red mud and the influence of variation in agitation rate, concentration and temperature on separation by adsorption technique has been investigated. The maximum transportation of sulfur compound from oil containing 730.67 mg dm−3 (0.025% by weight sulfur) of cyclohexanethiol was noted at 45°C. The adsorption follows first order kinetics and is a diffusion controlled process. The applicability of Langmuir isotherm indicates monolayer coverage of sulfur on the outer interface of red mud. Calcination of red mud and thermodynamic parameters suggest the favorable separation of cyclohexanethiol from kerosene oil by adsorption.
Mesophilic degradation of butyric acid in anaerobic digestion
Authors: Lin Chiu‐Yue , Hu Yun‐Yao
Published: July 2010

Seed sludges acclimatized with iso and normal butyric acids were used in batch‐type anaerobic digestion. Isomerization between iso and normal butyric acid occurred; the formation of isobutyric acid was independent of pH but the reverse process was pH dependent. The relative formation percentages for normal and isobutyric acid, based on the added butyric acid concentrations, were about 2.3% and 6.0%, respectively. Acetic acid inhibited normal butyric acid degradation less than isobutyric acid degradation. Based on the experimental findings, a pathway for the degradation of butyric acid to acetic acid is proposed.
Characterization of products of interaction between kaolin ore and ammonium sulphate
Authors: Fouda M. F. R. , Amin R. S. , Abd‐Elzaher M. M.
Published: July 2010

The reaction products resulting from the interaction between kaolin ore and ammonium sulphate depend on molar ratios between reactants, reaction temperature and time of interaction. The reaction products were characterized by means of XRD. They were composed of silica, unreacted kaolin ore, traces of iron, magnesium, calcium, titanium and NH4Al(SO4)2 and (NH4)3Al(SO4)3. The last compound was produced alone at 553 K, whereas mixtures of them were produced between 553 and 823 K after a short time of interaction (0.5 h). On other hand the former compound was produced alone after longer heating (c. 2 h). At 823 K, a mixture composed of Al2(SO4) and NH4Al(SO4)2 was identified after 0.5 h, whereas anhydrous aluminium sulphate was detected alone after heating the reaction mixture for 2 h. The transformation of (NH4)3Al(SO4)3 into NH4Al(SO4)3 and alumina leads to a decrease in the percentages of extracted alumina from kaolin ore at relatively higher temperatures and/or longer heating of reaction mixtures. The investigation was also devoted to establishing the possible reactions which lead to the formation of Fe2O3, MgO, CaO and TiO2 as soluble salts together with aluminium compounds. The percentages of their extraction are low compared with the original quantities found in kaolin ore. From the obtained results, both Al2(SO4)3 and NH4Al(SO4)2 can be prepared from local kaolin with a reasonable degree of purity which makes it possible to produce them for use for different industrial and pharmaceutical purposes.
Kinetic studies of Mucor miehei lipase in phosphatidylcholine microemulsions
Authors: Oliveira A. C. , Cabral J. M. S.
Published: July 2010

Ethanol—oleic acid esterification by a free and microencapsulated lipase from Mucor miehei, using dodecane as solvent and phosphatidylcholine as surfactant, was studied.

The initial esterification rate was influenced by the water content in the biphasic system. Kinetic studies with free and microencapsulated enzyme showed that the microencapsulation led to an increase of the kinetic parameters (Vmax and Km), probably due to an increase of the interfacial area. The reaction rate was also affected by the shaking rate, the temperature and the pH. The optimal temperature and pH achieved were, respectively, 40°C and 4.5 using free enzyme, and 50°C and 6 using microencapsulated enzyme.
Ionic mass transfer measurements in the case of submerged multijets impinging on to a flat surface
Authors: Krishna P. Gopala , Venkateswarlu P.
Published: July 2010

In the case of submerged multijets impinging on to a flat surface, the limiting current densities were measured at microelectrodes, fixed flush with the target surface using diffusion controlled electrode reactions (i.e. reduction of ferricyanide ion). The height of the multijet distributor from the target surface (Y) was varied from 5 to 9 cm. The numbers of holes of the distributor (N) studied were 76 and 141. The variation of mass transfer data with radial distance reveals the existence of two different regions, i.e. the impingement region and the wall jet region. The mass transfer rate increased with increase in Y in the impingement region. The effect of Y is negligible in the wall jet region. Decrease in N decreases the mass transfer rate in both the regions. The data are correlated separately for the two regions.
Microencapsulation of Lactococcus lactis within cross‐linked gelatin membranes
Authors: Hyndman Caroline L. , Groboillot Anne F. , Poncelet Denis , Champagne Claude P. , Neufeld Ronald J.
Published: July 2010

Lactococci were encapsulated within gelatin membranes cross‐linked with toluene‐2,4‐diisocyanate at an oil/water interface. Reagent toxicity was avoided by use of vegetable or silicone oil as a dispersant, and by minimizing cell exposure to the water insoluble cross‐linking agent during membrane formulation. Growth of cells within the gelatin microcapsules was observed during fermentation and acidification activity of the encapsulated cells increased with subsequent reuse. A microencapsulated cell density of 109 cfu cm−3 resulted in acidification of milk to pH 5.5 within 2.8 h, similar to that achieved in free cell fermentations.
Structure—activity relationships for hydroxyoxime metal extractants
Authors: Voelkel Adam , Szymanowski Jan
Published: July 2010

The distance‐based topological indices and connectivity indices were computed for various homologues of hydroxyoximes and correlated with the partition data and the rate of copper extraction from acidic sulphate solutions. The distance‐based topological indices are more sensitive to the structural changes in extractant molecule than the connectivity indices.
The physicochemical properties of the mixed solvent of 2‐piperidineethanol, sulfolane and water
Authors: Xu Shuo , Wang Yi‐Wei , Otto Frederick D. , Mather Alan E.
Published: July 2010

The physicochemical properties of the mixed solvent of 2‐piper‐idineethanol (2‐PE), sulfolane (TMS) and water were determined over a wide range of temperatures and compositions. The density, the viscosity and the dissociation constant, as well as the solubility of N2O in this mixed solvent were correlated as a function of temperature and composition over the entire experimental range. The models are useful not only for the ternary solvent system, but also for the binary solvent systems, such as 2‐PE+H2O and TMS+H2O. From the regression, it has been found that the interaction of aqueous 2‐PE solution and aqueous TMS solution is negligible.
Influence of serum proteins on the kinetics of attachment of vero cells to cytodex microcarriers
Authors: Mukhopadhyay Asok , Mukhopadhyay Satya N. , Talwar Gursaran P.
Published: July 2010

The attachment characteristics of the Vero cell line on microcarriers has been found to be influenced by the serum proteins. Significant quantities of serum proteins were found to be adsorbed on the carrier surface, which resulted in decreased exchange capacity and a lower attachment rate constant. The kinetics of attachment followed primarily first order with respect to the concentration of free cells. With positively charged microcarriers the attachment process exhibited two distinct phases, an initial phase of normal attachment followed by a second phase characterized by a lower rate of attachment. The attachment rate constant in the first phase (0·062 min−1) was reduced to 0·01 min−1 in the second phase. Presumably, at a low concentration of free Vero cells, the attachment process is retarded by unadsorbed Bovine Serum Albumin (BSA) and other serum proteins present in the medium.
Kinetics of aspartame precursor synthesis catalysed by Pseudomonas aeruginosa elastase
Authors: Lee Kong H. , Lee Pat M. , Siaw Yew S. , Morihara Kazuyuki
Published: July 2010

Elastase isolated from Pseudomonas aeruginosa IFO 3455 was found to be an efficient protease to catalyse the synthesis of N‐benzyloxycarbonyl‐aspartyl‐phenylalanine methyl ester, the precursor of the dipeptide sweetener, aspartame. The influence of methanol as a cosolvent in this synthetic reaction was investigated. It was found that the synthesis of the dipeptide precursor was most efficient in 25% (v/v) methanol, pH 7·0 at about 25°C for a reaction time of about 3 h. However, the activity of the enzyme was greatly reduced in 90% methanol. The values of K and k2 for N‐benzyloxycarbonyl‐aspartic acid were 0·17 mol dm−3 and 11·9 mol dm−3 s−1 respectively.
Overproduction of EcoRI and SpA::EcoRI fusion protein by Escherichia coli employing the combinations of three different types of multicopy plasmids: Comparison of plasmid stabilities and product concentrations
Authors: Wu Xiaoan , Brandes Lutz , Maschke Hans E. , Schügerl Karl
Published: July 2010

The copy numbers of the expression plasmids (pRTF309 + and pMTC48), the repression plasmids (pcI857 and pRK248cI) and the protection plasmid (pEcoR4) in recombinant E. coli JM103 were investigated. In the absence of the protection plasmid, the copy number of the expression plasmid dropped; in its presence, the copy numbers of the expression plasmids increased after gene expression by temperature‐shift induction. The copy numbers of the repression plasmids were not influenced by the presence or absence of the protection plasmid. The copy numbers of the latter were not changed during temperature‐induced gene expression. In the absence of the protection plasmid, the product concentration (EcoRI enzyme activity) was very low. With the plasmid combination pRTF309 +, pRK248cI, and pEcoR4, the enzyme (EcoRI) activity was higher, but with the plasmid combination pMTC48, pRK248cI, pEcoR4, the enzyme (SpA::EcoRI) activity was highest.
Self‐diffusion of strontium ions in hydrous zirconia and stannic oxide
Authors: Misak Nasr Z. , Ghoneimy Hussein F. , Mikhail Etidal M. , Shabana El‐Said I.
Published: July 2010

Self‐diffusion coefficients (D̄) of strontium ions in hydrous zirconia and stannic oxide heated at different temperatures have been determined at different apparent capacities. The study throws some light on the effects of capacity, acidity and porous texture on D̄. Except in the totally microporous stannic oxide heated at 50–200°C, D̄ in both oxides decreases continuously with capacity. For the former sample, the size of the diffusing entity seems to be relatively more important, and D̄ remains almost the same over a wide capacity range.
Synthesis, characterization and antitumour studies of metal chelates of N1‐isonicotinoyl‐3‐methyl‐4‐(p‐hydroxybenzilidene)‐2‐pyrazolin‐5‐one
Authors: Kuncheria Joshi , Aravindakshan K. K.
Published: July 2010

The cobalt(II), nickel(II) and copper(II) complexes of N‐Isonicotinoyl‐3‐methyl‐4‐(p‐hydroxybenzilidene)‐2‐pyrazolin‐5‐one (IMHBP) with different counter anions have been prepared and characterized. An octahedral geometry has been assigned to the cobalt(II) and nickel(II) complexes and a square‐planar structure to the copper(II) complexes. IMHBP acts as a neutral bidentate ligand in all these complexes by coordinating through the oxygen atoms of the amide group and carbonyl at position‐5. The other coordination sites are satisfied by anions alone or anions and water molecules. The ligand and the complexes were screened for their possible antitumour activity. The copper(II) complexes are appreciably active in reducing mice tumours.
Immobilization of penicillin acylase on copolymer of butyl acrylate and ethylene glycol dimethacrylate
Authors: Bryjak Jolanta , Noworyta Andrzej
Published: July 2010

The effects of glutaraldehyde, enzyme concentrations and reactants volumes, ionic strength, pH value and carrier particle diameter on immobilization of penicillin acylase onto acrylic carriers were studied. The activity of immobilized enzyme preparations was also studied over a range of pH values and temperatures and thermal and pH stabilities were determined. The use of the immobilized preparation for penicillin G hydrolysis in a batch reactor was investigated. The immobilized enzyme gave a significant reduction in hydrolysis time compared to hydrolysis by the native enzyme.
An investigation of phosphate adsorption by Clays and its relation to the problems of eutrophication of the river stour, Kent
Authors: Fox Ian , Malati Mounir A.
Published: July 2010

Eutrophication of the River Stour in Kent and its potential remedy are related to the adsorption of phosphates by its bed deposits, which are derived largely from Gault and Weald clays. The main minerals in these clays are: kaolin, mica, vermiculite and smectite. Four reference samples of these clays and samples of Gault and Weald clays were characterised by X‐ray diffraction, thermal analysis (DTA and TGA) as well as by infrared spectroscopy and BET surface area. For the reference clays, also characterised by chemical analysis, the cation exchange capacity (CEC) and the point of zero charge (PZC) were determined. A kinetic study of phosphate adsorption showed an initial fast step followed by a slower process. The effects of pH, phosphate concentration, rate of shaking and temperature, on the rate of adsorption, are reported. Desorption of phosphate also revealed two consecutive kinetic stages. Adsorption isotherms of phosphate on the reference clays are presented over a range of pH values. In the case of kaolin, the heat of adsorption was found to be 17 kJ mol−1. Electrophoretic mobilities of the mica particles were measured in the presence and in the absence of phosphate, over a pH range. The mechanisms of adsorption are discussed.
Influence of cultural conditions on coal solubilization by Penicillium simplicissimum
Authors: Achi Ome K. , Emeruwa Augustine C.
Published: July 2010

Sub‐bituminous coal, preoxidized with nitric acid and treated with sodium hydroxide solutions to obtain a water‐soluble extract, was used for the study of coal degradation by Penicillium simplicissimum. The influence of different carbon and nitrogen sources was examined in connection with growth and production of acid‐precipitable coal polymers. The yield was increased after the addition of maltose, lactose and cellobiose while glucose, fructose and xylose had little effect. An organic nitrogen source, yeast extract, was an improved source of nitrogen compared with ammonium chloride. The coal‐degrading system appeared before the depletion of the carbon or nitrogen source. In addition, the effects of initial pH of the culture medium demonstrated an increase in the yield of coal polymers up to a pH of 7.5. Above this pH, non‐biological catalysis increased gradually. However Ca2+ and Mn2+ increased the yield of coal polymers over a 14‐day period, but yield was unaffected by Cu2+, Al3+ and Fe2+.
Causticization of sodium carbonate with rock‐salt type magnesium aluminium oxide formed by the thermal decomposition of hydrotalcite‐like layered double hydroxide
Authors: Sato Tsugio , Onai Satoshi , Yoshioka Toshiaki , Okuwaki Akitsugu
Published: July 2010

The causticization behaviour of Na2CO3 with rock‐salt type oxide, Mg2(1‐x/(2+x) O (M = Al3+ and Fe3+, x = 0.2 and 0.33), produced by the thermal decomposition of hydrotalcite‐like layered double hydroxide was investigated at 30–60°C. The degree of causticization increased with increasing the molar ratio of [rock‐salt type oxide]/[Na2CO3] and increasing the temperature but decreased with increasing the initial concentration of Na2CO3. The causticization behaviour could be adequately described by the equation of anion exchange equilibria between CO32‐ and OH− for layered double hydroxide.
Growth and kinetic parameters of ajuga hairy root in fed‐batch culture on monosaccharide medium
Authors: Uozumi Nobuyuki , Kohketsu Katsuhito , Kobayashi Takeshi
Published: July 2010

The batch culture of a transgenic plant, Ajuga hairy root, in sucrose and MS medium exhibited glucose and fructose accumulation with culture time and depletion of phosphate ion after 16 days. The use of a monosaccharide instead of sucrose in fed‐batch culture avoided the difficulty of estimating the concentration of saccharides. Glucose was the most adequate monosaccharide for attaining a high cell mass. In fed‐batch culture using a turbine blade fermentor, 27.2 kg‐dry cell m−3 was obtained at 39 days in glucose medium, with the final cell mass and production of 20‐hydroxyecdysone increasing 2.6‐fold and 2.0‐fold, respectively, compared with batch culture results with sucrose in a shake flask. The growth of the hairy root was divided into two phases, an exponential growth phase and linear growth phase. The linear growth phase from 5 through 25 kg‐dry cell m−3 predominated over the growth curve. On the basis of the data of the fed‐batch culture with glucose, the cell yield, 0.77 g g−1, and maintenance coefficient, 0.105 g g−1 day−1, for Ajuga hairy root were comparable to those of various calluses. The cell yield of the plant cell was larger than the yields of microorganisms and the maintenance coefficient was smaller.
Salt effect in vapour liquid equilibria
Authors: Subbaiah T.
Published: July 2010

In the present work the effect of ammonium chloride on the vapour liquid equilibrium of the system 1,4 dioxane‐water at atmospheric pressure of 760 ± 1 mm Hg has been studied. It was observed that the ammonium chloride is helpful in shifting the azeotropic composition. Linear relationships are developed between the relative volatilities and salt concentrations.
Inactivation of rice bran lipase with metal ions
Authors: Munshi S. K. , Bhatia Neena , Sekhon B. S. , Sukhija P. S.
Published: July 2010

The inactivation of rice bran lipase was studied in vitro and in vivo using metal ions in methanol or HCl. Lipase was extracted from rice bran in 0.1 M potassium phosphate buffer, pH 7.0 and purified by ammonium sulphate fractionation. The 25–55% ammonium sulphate fraction was subjected to DEAE‐cellulose ion exchange chromatography and the fraction (F6) eluted at Ve/Vo of 14.37 was purified about 333‐fold. In‐vitro studies on F6 lipase showed that Fe3+ and Ni2+ completely inhibited the lipase activity at 5 × 10−5 M concentration, while Zn2+ and Cu2+ did so at 2.5 × 10−4 M. The results on in‐vivo inactivation of rice bran lipase showed that Fe3+ and Ni2+ at 200 μg g−1 significantly checked the release of free fatty acids (FFA) from rice bran for 6 days of storage when compared with using concentrated HCl (2%, v/w) only. The triglyceride content of oil was also maximum with Fe3+ and Ni2+ treatment at 200 μg g−1. The present results suggest that Fe3+ and Ni2+ could be effectively used to arrest the release of FFA in rice bran and thus contribute to improving the edible quality of rice bran oil.
Enzymatic synthesis of (R)‐ and (S)‐2‐cyclohexen‐1‐ol
Authors: Izumi Taeko , Nakamura Toshihiko , Eda Yuji
Published: July 2010

The synthetically useful chiral synthons (R)‐ and (S)2‐cyclohexen‐1‐ol can be prepared by an enantioselective transesterification of racemic trans‐2‐(phenylseleno) cyclohexanol using lipases, followed by selenoxide elimination and hydrolysis.
Removal of phosphate by foam‐immobilized Phormidium laminosum in batch and continuous‐flow bioreactors
Authors: Garbisu Carlos , Hall David O. , Serra Juan L.
Published: July 2010

Free‐living and polyvinyl foam‐immobilized cells of Phormidium laminosum were studied for their phosphate uptake characteristics. Initial phosphate uptake rates yielded hyperbolic curves when plotted against the external phosphate concentration, indicating the existence of a saturatable transport system. The phosphate uptake rates of N‐starved free‐living cyano‐bacteria were also examined and showed that N‐starvation led to lower uptake rates. The addition of nitrate to N‐starved cyanobacteria markedly increased phosphate uptake.

Phosphate uptake by free and immobilized cyanobacteria was inhibited in the dark and stimulated by the presence of calcium ions or bicarbonate. No phosphate uptake was observed when a chelating agent, such as ethylenediaminetetraacetic acid (EDTA), was added to the cultures.

Several bioreactors were established for initial studies in using immobilized cyanobacteria for the removal of phosphate from water. Three different types of batch fluidized‐bed, as well as two continuous‐flow bioreactors (i.e. fluidized‐ and packed‐bed), were examined. Although cyanobacteria immobilized on the polymer foams did not show high phosphate uptake efficiencies, simultaneous removal of nitrate and phosphate from water by means of N‐starved immobilized cyano‐bacteria appeared to be a promising possibility for future development.
Biotechnology and pollution monitoring: Use of molecular biomarkers in the aquatic environment
Authors: Livingstone David R.
Published: July 2010

Metals and organic contaminants, present in the water‐column, sediment or food, are readily accumulated by aquatic organisms. Exposure to and toxic effects of contaminants can be measured in terms of the biochemical responses of the organisms—so‐called molecular biomarkers. The applications, advantages and limitations of such diagnostic and prognostic tests are discussed. The hepatic biotransformation enzyme cytochrome P4501A in fish and other vertebrates is specifically induced by organic contaminants such as aromatic hydrocarbons, PCBs and dioxins, and is used as a biomarker of exposure to organic pollution. Its induction is involved in chemical carcinogenesis via catalysis of the covalent binding of organic contaminants to DNA (DNA‐adducts). P4501A‐induction, measured as enzyme activity, enzyme amount, or mRNA, has been successively used in many field studies, involving some 27 fish species, in USA and Europe. Metallothioneins (MTs) bind and are specifically induced by metals such as Cd, Hg, Ag and Cu, and are used in both vertebrates and invertebrates as a biomarker for metal exposure. Bulky, hydrophobic DNA‐adducts are used as a biomarker for organic contaminant damage. MTs (measured at protein and mRNA levels) and DNA‐adducts (32P‐postlabelling method) have been applied less extensively in the field than P4501A, but the results are similarly encouraging. Biomarkers should be used as part of an integrated programme of pollution monitoring, involving also general measurements of biological damage and animal health, and analysis of chemical contaminants in the biota and environment. Commercial availability of antibodies and mRNA probes will accelerate the widespread application of these molecular biomarkers.
Synthesis of monodispersed micaceous iron oxide by the oxidation of iron with oxygen under hydrothermal conditions
Authors: Uchida Satoshi , Sato Tsugio , Okuwaki Akitsugu
Published: July 2010

The oxidation behavior of iron powder with oxygen was investigated in 5–25 m NaOH solutions at 5 MPa of oxygen partial pressure and 130–290°C, where m = mol(kg H2O)−1. Monodispersed micaceous iron oxide, α‐Fe2O3, was synthesized by the oxidation of iron powder with 5 MPa of oxygen in 10–16 m NaOH solutions at 250–270°C. The diameter of micaceous iron oxide greatly changed depending on the reaction conditions such as the temperature, reaction time and concentrations of NaOH and coexisting ions.
Design and operation of rotating‐disk foam‐breakers fitted to tower fermenters
Authors: Takesono Satoshi , Onodera Masayuki , Yamagiwa Kazuaki , Ohkawa Akira
Published: July 2010

The design and operation of rotating‐disk mechanical foam‐breakers (MFRDs) fitted to tower fermenters, i.e. bubble columns (BCs), treating various foaming liquids were studied. The foam‐breaking behaviour of MFRDs fitted to BCs and the foaming behaviour of BCs were investigated respectively from the changes in the required critical disk rotational speed Nc and those in liquid hold‐up in the foam, øL. The effects of operating conditions on Nc and øL were evaluated quantitatively. On the basis of their results, the empirical equations for predicting Nc and øL in foam‐breaking regions, useful for the design and operation of MFRDs fitted to BCs, were obtained. The level of the required foam‐breaking power Pkc of MFRDs was also clarified in relation to the level of øL which reflects the foaming intensity of BCs and is related to the difficulty of foam‐breaking.
Optimization of the synthesis of furanic polyols from hemicellulose hydrolyzates leading to a route to l‐arabinose as a by‐product
Authors: Bonzon Valérie , El‐Mahdi Halima , Rigal Luc , Borredon Marie‐Elisabeth
Published: July 2010

Extending the synthesis of furanic polyols to mixtures of sugars representative of hemicellulose hydrolyzates leads to important yields of furanic polyols of glucose and xylose together with high yields of unreacted L‐arabinose.
Microencapsulation of silicone oils within polyamide—polyethylenimine membranes as oxygen carriers for bioreactor oxygenation
Authors: Poncelet Denis , Leung Ricky , Centomo Liana , Neufeld Ronald J.
Published: July 2010

Silicone oils were microencapsulated within polyamide (nylon) membranes cross‐linked with polyethylenimine. Solubility of oxygen within the silicones, whether encapsulated or not, was approximately 6 mmol dm−3, representing solubilities approximately 20‐fold higher than that of oxygen in water. The response time of oxygen transfer from the microencapsulated oxygen carrier was less than 2.5 s; a more precise measurement was limited by the response time characteristics of the oxygen probe. Assuming that the bioreactor volume consists of 10–20% (v/v) microencapsulated silicone oil, this represents an enhancement of the oxygen reservoir by a factor ranging from 4 to 7 and improvement in oxygen transfer rates greater than 15‐fold due to the greatly increased specific surface area in comparison to conventional bubble aeration. Circulation of oxygenated silicone oils encapsulated within inert polymeric membranes may provide an efficient alternative to bioreactor oxygenation with shear sensitive cell systems, or in fermentations with high oxygen requirements.
Photodecomposition of 2,4‐dichlorophenoxyacetic acid: Influence of pH
Authors: Chamarro Esther , Esplugas Santiago
Published: July 2010

The photodecomposition of 2,4‐dichlorophenoxyacetic acid (2,4‐D) in aqueous solutions has been studied by using ultraviolet radiation in an annular batch reactor. The dark reactions were negligible. For short irradiation times, a first order reaction was found with respect to the absorbed radiation and a simple mechanism of this reaction at initial times has been proposed. pH influences the reaction rate only for long times of irradiation, possibly due to the formation of humic acids in the reaction medium.
Mass transfer and reaction of trimethylamine in a three‐phase biological reactor
Authors: Partidário P. J. , Carrondo M. J. T.
Published: July 2010

A model system, consisting of a mixed culture of microorganisms, was used to study the performance of a bench‐scale packed bed bubble column (PBC) bioreactor treating trimethylamine. Three mesophilic bacterial strains were selected, mixed and acclimatized to grow with trimethylamine as the sole carbon source; degradation kinetic constants were determined for a bacterial suspension system. Gas transfer to the liquid phase was modelled in order to characterize solute transport and availability into the biofilm. The overall performance of the system is discussed based on mass transfer considerations.
Uptake and recovery of gold by immobilized persimmon tannin
Authors: Nakajima Akira , Sakaguchi Takashi
Published: July 2010

Some attempts were made to recover gold from aqueous systems using immobilized persimmon tannin. This adsorbent adsorbed gold from solutions containing hydrogen tetrachloroaurate(III) with high efficiency, whereas there was minimal adsorption from solutions containing gold(I) sodium thiomalate and sodium dicyanoaurate(I). The adsorption of gold was rapid, and was affected by the pH of the solution, temperature, external gold concentration and amount of adsorbent. Adsorbed gold was easily desorbed with 1 mol dm−3 thiourea solution, indicating that immobilized persimmon tannin can be repeatedly re‐used for the recovery of gold using adsorption‐desorption cycles.
Xylanase production by Bacillus polymyxa
Authors: Piñaga F. , Peña J. L. , Vallés S.
Published: July 2010

Bacillus polymyxa produced high levels (12–13 U cm−3) of extracellular xylanases when grown in a complex medium containing yeast extract and oat spelt xylan as nitrogen and carbon sources respectively. Substantially lower yields of enzyme were produced during growth on the monosaccharides glucose, arabinose and xylose. Meagre growth occurred when ammonium sulphate, instead of yeast extract, was used as nitrogen source. When assayed in culture broth supernatants, xylanase showed an optimum activity in 48°C and at pH values in the range 5.0–6.5. Under such conditions, the half‐life of this xylanase preparation was 8 h. Mn2+ showed a strong inhibitory effect on the enzyme, but inhibition by EDTA (27% w/v) suggested dependence on a metallic ion. SDS‐PAGE and zymogram overlay showed that up to five separate xylanases in the range of 20 to 116 kDa were produced.
Synthesis of some new heterocyclic systems derived from 2‐acetylbenzimidazole
Authors: Hozien Zeinab A.
Published: July 2010

The named compound was reacted with thiosemicarbazide and/or semicarbazide to produce the corresponding condensation products II and V respectively. Reaction of II with chloroacetic acid in ethanol containing anhydrous sodium acetate yielded III. Condensation of III with aromatic aldehydes yielded the corresponding arylidene derivatives (IV). Oxidation of the semicarbazone V with selenium dioxide gave 2‐(1,2,3‐selenadiazole‐4‐yl)benzimidazole (VIa, b) while with thionyl chloride it gave 2‐(1,2,3‐thiadiazole‐4‐yl)benzimidazole (VIIa, b). The chalcones of 2‐acetyl and/or 1‐methyl‐2‐acetylbenzimidazole were condensed with hydrazine hydrate, phenylhydrazine and/or hydroxylamine to produce 2‐(5‐aryl‐1(H)‐pyrazolin‐3‐yl)‐, 2‐(5‐aryl‐1‐phenyl‐2‐pyrazolin‐3‐yl)‐ and 2‐(5‐aryl‐2‐isoxazolin‐3‐yl)benzimidazole (IX, X, XI) respectively.
Analysis of niobium, tantalum and titanium extracted from tantalite and columbite chlorination
Authors: Ruiz María Del C. , González Jorge A. , Olsina Roberto A.
Published: July 2010

Several analytical methodologies have been developed for determining niobium, tantalum and titanium concentrations in the products of columbite‐tantalite chlorination from the San Luis Province (Argentina). The ore mixed with carbon was attacked with gaseous chlorine in different working conditions. Volatile products were dissolved in concentrated hydrochloric acid after being condensed when coming out of the reactor. The results obtained from molecular absorptiometry in the UV‐visible region of the spectrum, combined with previous separation of the elements studied, were satisfactory. X‐ray fluorescence, carried out on solutions from the dissolution of previously separated oxides gave results in agreement with those obtained by absorptiometry, the former methodology being more versatile than the latter. In all cases analytical results were compared with standards and the errors produced are reported.
Adsorption of disperse dye by powdered activated carbon
Authors: Lin Sheng H.
Published: July 2010

The purpose of this laboratory study is to investigate the effectiveness of powered activated carbon (PAC) on the removal of chemical oxygen demand (COD) and color of disperse dye and the effect of PAC particle size on the treatment efficiency. The adsorption isotherm parameters for the Langmuir, Freundlich and BET model are determined using the adsorption data. It has been found that the multilayer BET isotherm yields significantly better fit to the observed data than the monolayer ones. A simplified mass transfer model is proposed in the present work also for estimating the external mass transfer coefficient using the initial adsorption data at low PAC dosage.
Sodium inhibition and sulphate reduction in the anaerobic treatment of mussel processing wastewaters
Authors: Soto Manuel , Méndez Ramón , Lema Juan M.
Published: July 2010

An anaerobic filter treating high saline wastewaters from a sea food processing industry was subjected to sodium and sulphate shocks. Sodium concentrations ranging from 5 to 12 g dm−3 had no significant influence on the methane production rate, with maximum value of 15 kg COD m−3 day−1. The sulphate‐reducing capacity of the filter was estimated at 2.2 kg SO42‐ m−3 day−1. When using propionic or acetic acid as substrates, the sulphate‐reducing activities were 0.021 and 0.006 g SO42‐ g−1 VSS day−1 respectively. Determination of the methanogenic activity of the sludges indicated that sodium concentrations of 14 g dm−3 caused a 50% inhibition of the methanogenic activity from the anaerobic filter. However, when using the anaerobic filter effluent as the assay medium, the sodium concentration giving the same percent inhibition was 17.7 g dm−3, indicating a beneficial effect probably due to the antagonism caused by the presence of other sea salts. The sludge showed a higher tolerance to sodium toxicity than that reported in previous literature, which can be explained as a consequence of sludge adaptation.
Novel dyes and intermediates for synthetic‐polymer fibres: Synthesis and dyeing performance of 1‐aryl‐5‐hetarylphenylazo‐4‐hydroxypyrazole derivatives and their isomeric 1‐hetarylphenyl‐5‐arylazo analogues as disperse dyes for polyester fibre
Authors: Hanna M. A.
Published: July 2010

In a multi‐step synthesis, a series of 5‐arylazo‐4‐hydroxy‐1‐(substituted imidazol‐5‐on‐2‐ylphenyl)pyrazole‐3‐carboxanilide dyes (VIIIa—i), their isomeric 4‐hydroxy‐1‐phenyl‐5‐(substituted imidazol‐5‐on‐2‐ylphenylazo)pyrazole‐3‐carboxanilide analogues (XIIa—i) and a related series of 4‐hydroxy‐1‐phenyl‐5‐(substituted oxazol‐5‐on‐2‐ylphenylazo)pyrazole‐3‐carboxanilide derivatives (XIa—h) were prepared with a view to evaluating and comparing the assessment of their dyeing performance on synthetic polymer fibres. Fastness ratings were generally good, particularly for the imidazolonylphenylazo series (XIIa—i). Substituents of the latter type are of greater value in attaining optimum light fastness in these dyestuffs. The structures of the synthesized dyes were inferred from elemental and spectral data and, whenever possible, by alternative synthetic routes.
Immobilization studies of an industrial penicillin acylase preparation on a silica carrier
Authors: Fonseca L. P. , Cardoso J. P. , Cabral J. M. S.
Published: July 2010

Penicillin acylase (EC 3.5.1.11) was immobilized by covalent binding on a silica gel carrier activated by silanization. High immobilization yields, operational stability, enzyme loading and support reutilization capacity were obtained. The effects of several variables on the activation of the support and on the immobilization method were studied.

Other supports and immobilization methods were assessed for the immobilization of penicillin acylase and compared with the basic process used.

Activity versus temperature, pH, buffer molarity and penicillin concentration profiles were determined and compared for the free, crosslinked and covalently‐bound silica carrier penicillin acylase preparations.

The hydrolysis performance of the latter preparation was assessed in a batch basket reactor and the time course of the hydrolysis reaction modelled by a two parameter model equation.

The operational stabilities of penicillin acylase coupled covalently to the silica gel support and immobilized by a crosslinking procedure using glutaraldehyde were also compared.