bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on calcium sulphate dihydrate formed in media rich in phosphoric acid. I. Precipitation of calcium sulphate dihydrate
Authors: Adami A. , Ridge M. J.
Published: July 2010

A study has been made of the properties of the products of digesting calcium sulphate hemihydrate in media containing finally 29·4% P2O5. Hydration to the dihydrate occurred at temperatures between 35° and 65°. The product was almost phosphate‐free when the reaction was carried out between 52·5° and 57·5°.
Removal of yttrium ions from aqueous solution by ion flotation
Authors: Rose M. W. , Sebba F.
Published: July 2010

Conditions for the concentration of yttrium from aqueous solution by ion flotation using α‐sulphonated fatty acids were studied. The effects of change of collector and colligend concentration and pH, as well as the effect of interfering ions, were investigated. Maximum recovery was 99·5%.
Some aspects of the behaviour of potassium sulphate in aqueous solutions
Authors: Halstead W. D.
Published: July 2010

The solubility of potassium sulphate in sulphuric acid at 293°K has been determined. The effects of traces of Fe2+, Fe3+ and Cr3+ ions on the recrystallisation of potassium sulphate from both neutral and acidic solutions have been studied. While Fe2+ ions had no significant effect, concentrations of 0.07 g Fe3+ or 0.02 g Cr2+ per 100 g H2O inhibited crystallisation of potassium sulphate from 100% supersaturated solutions. A method for purifying potassium sulphate contaminated with Fe3+ and Cr3+ ions, by means of fractional crystallisation, is outlined.
Absorption of oxygen by 2‐ethylhexaldehyde
Authors: Ladhabhoy M. E. , Sharma M. M.
Published: July 2010

The kinetics of absorption of oxygen by 2‐ethylhexaldehyde dissolved in 2‐ethylhexanoic acid at concentrations up to 1.38 × 10−3 mole/cm3 (20 wt.‐%), in the presence of manganese acetate, was studied in a stirred cell and in bubble and packed bubble columns. Diffusion of oxygen was found to play a major role. The reaction was first order in oxygen and second order with respect to the aldehyde, and the overall third‐order rate constant was found to be 2.98 × 107 cm6 mole−2 sec−1 at 30°. The effect of cobaltous acetate on the specific rate of absorption of oxygen was also studied and manganese acetate was found to be the better catalyst.
Mathematical models of fermentations and a simulation of the griseofulvin fermentation
Authors: Calam C. T. , Ellis S. H. , McCann M. J.
Published: July 2010

A number of models which have recently appeared in the microbiological literature are described and discussed. A simulation of the griseofulvin fermentation is also reported.

Models described range from simple models involving curve‐generating equations providing parameters which describe fermentation phenomena adequately for optimisation purposes, to more elaborate mechanistic models which involve the quantity of substrate required to produce cells and products. Beyond this are complex models capable of describing biochemical mechanisms and able to elucidate a fermentation at a deeper level.

The construction of the model for griseofulvin fermentation and its comparison with actual results have shown how a model can bring to light new ideas about the way fermentations behave and point to the most useful areas of investigational work.
Composition of the gases formed in electrical insulating oils
Authors: Davies I.
Published: July 2010

The composition of the gases formed in electrical insulating oils can be used to detect the onset of faults in the plant. A number of methods of analysis are in use. This paper describes a method of expressing the results of an analysis which shows that most samples fall into a pattern from which deviations are assumed to indicate the presence of a fault.

The procedure is described and some examples given which illustrate its use in practice.
Factors affecting the skid‐resistance of calcined bauxite
Authors: Dews S. J. , Bishop R. J.
Published: July 2010

Calcined bauxite (RASC Grade from Guyana) has been demonstrated as an excellent, albeit expensive, aggregate material for road surfacing which has unique properties with regard to its performance under traffic. Its high wear resistance and anti‐skid properties have resulted in a dramatic decrease in the number of accidents wherever the surface has been laid. This paper discusses results from an examination of certain physical and chemical properties of this heterogeneous material and relates them to its outstanding performance as a surfacing aggregate.
Structural changes of flavylium salts
Authors: Harper Kevi N. A.
Published: July 2010

A general discussion is presented of the effects of hydroxylation pattern upon the structural changes of flavylium salts and their stability at different pH levels. The discussion is based upon the results of spectrometric and polarographic investigations of flavylium salts and incorporates hitherto unpublished data for the anthocyanidin, cyanidin chloride.
Equilibrium distribution data for salicylic acid + water + solvent systems
Authors: Sinha Rathindranath , Rao R. Jagannadha
Published: July 2010

Equilibrium distribution data have been presented at 30 °C for the distribution of salicylic acid between water and each of the solvents benzene, toluene, xylene and kerosene. The equilibrium distribution plots reveal that except in the case of kerosene, the acid favours the solvent layer more than the aqueous phase at higher concentrations, i.e., above 0.04 wt‐ % acid content. At lower concentrations the acid prefers more the aqueous phase. In the case of kerosene, the acid favours only the aqueous phase uniformly at all concentrations. The lower hydrocarbons seem to be better suited for the extraction of salicylic acid from the aqueous phase.
Transient behaviour of encapsulated enzyme reactor systems
Authors: Choi Paul S. K. , Fan Liang T.
Published: July 2010

Mathematical models are developed for the transient behaviour of encapsulated enzyme reactor systems such as the continuous stirred tank reactor (CSTR) and the packed bed tubular reactor. The rate processes taking place in the encapsulated enzyme bed are approximated by using a combined rate control model of enzyme reaction and membrane diffusion. The change in transient substrate concentration is obtained by using the developed rate expression in the material balance over the substrate as a function of time for the CSTR and as a function of time and position for the packed bed tubular reactor. The effects of various parameters such as the enzymic reaction rate constant, Michaelis constant, diffusional resistance of membranes, and Peclet number on the substrate concentration distribution, which varies with respect to operating time, are investigated. This study affords insight into the transient operating characteristics of the encapsulated enzyme reactor system. The results should be useful in understanding the start‐up performance of the reactor systems and to control such reactor systems at desired operating conditions.
Hydration of calcium sulphate hemihydrate in the presence of calcium hydroxide
Authors: Ridge Mayhew J. , King George A.
Published: July 2010

A study has been made of the effects of calcium hydroxide on the hydration of calcium sulphate hemihydrate in accelerated, inhibited and unmodified systems, using techniques developed in this laboratory. The results were interpreted in terms of an equation developed earlier, and the parameters k (which is related to the transport of matter in the system) and α0 (which is a measure of heterogeneous nucleation) determined. A small addition of calcium hydroxide leads in all cases to a sharp increase in k. Further additions lead only to effects caused by dilution of the system. Calcium hydroxide has complex effects on α0. These are large in inhibited systems. The basic effects of calcium hydroxide are to increase the concentration of hydroxyl ions which have specific effects, increase the concentration of Ca2+ ions, adsorb inhibitors and extend the system as an inert diluent.
Effect of the method of preparation and pretreatment on the texture of alumina and related catalysts
Authors: Ravindram Maddury , Murty Koganti S.
Published: July 2010

The effect of the method of preparation and pretreatment on catalyst texture was investigated in the case of alumina, silica‐alumina, 10 × molecular sieve and thoria catalysts. All the catalysts were characterised with respect to their specific surface area, surface acidity, pore size distribution and pore volume. The above properties were found to reflect the textural changes that might have been undergone by the catalyst surface as a result of the method of preparation and pretreatment. The method of preparation was found to influence markedly the acidity of the surface and to a lesser extent the surface area and pore size distribution. Acid‐treatment was found to increase selectively the acidity of the catalyst while heat‐treatment was found to decrease proportionally the acidity as well as surface area of the catalyst.
Adsorption of dyestuffs from aqueous solutions with activated carbon I: Equilibrium and batch contact‐time studies
Authors: McKay Gordon
Published: July 2010

The ability of one activated carbon to remove dyestuffs from aqueous solutions has been investigated. The range of dyestuffs includes acidic, basic, disperse and direct dyes, and several factors have been studied, namely, agitation, initial dye concentration, adsorbent concentration, adsorbent particle‐size range, dye solution temperature, pH of solution and salt concentration.
Kinetics and mechanism of slag cement hydration
Authors: Abo‐El‐enein S. A. , Ata A. A. , Hassanien A. , Sh. Mikhai R.
Published: July 2010

Granulated blastfurnace slag and Portland cement were first ground separately into samples of different fineness, covering the range 2500 to 6000 cm2 g−1 in Blaine areas. For each sample, various slag‐cement mixtures were prepared using Portland cement with the same Blaine area. Paste‐hydration of the various slag‐cement mixtures was carried out at room temperature for different curing periods; the initial W/C ratios used were 0.30 and 0.40. From the results of combined (non‐evaporable) water, free slag and free lime contents of the hardened pastes at various hydration ages, and their relation to the development in compressive strength, the mechanism of the hydration process could be specified. The suggested mechanism includes six hydration stages; these are (i) pre‐dormant, (ii) first dormant, (iii) first acceleration, (iv) second dormant, (v) second acceleration and (vi) diffusion period. The beginning and duration of each hydration period depended primarily on the fineness and the constitution of the slag‐cement dry mixture.
Lightfastness and flash photolysis of hydroxyanthraquinones
Authors: Allen Norman S. , McKellar John F. , Moghaddam Bahram M.
Published: July 2010

The photostability of the commercially important dye 1,2‐dihydroxyanthraquinone (alizarin) is compared with that of four other structurally related hydroxyanthraquinones in both solution and polymer substrates. In solution the flash photolysis experiments showed that in a polar solvent, 2‐propanol, the 1,2‐hydroxy derivative is the least reactive. A similar trend in lightfastness (LF) is found when the dyes are applied to the highly polar substrate nylon‐6,6.
Adsorption from aqueous solution by δ‐manganese dioxide II. Adsorption of some heavy metal cations
Authors: Gray Malcom J. , Malati Mounir A.
Published: July 2010

The adsorption isotherms of M2+ ions (M2+ = Ni2+, Co2+, Cd2+, Zn2+ and Mn2+) on the K+‐form of δ‐MnO2, at pH 6 and at different temperatures, fitted the Langmuir equation and an apparent heat of adsorption, Q, was found to be ‐ 78, ‐ 33, ‐ 34, ‐ 19 and ‐ 15 kJ mol−1 respectively. The adsorption capacity of δ‐MnO2 increased in the series: Ni2+ < Co2+ < Cd2+ ± Zn2+ < Mn2+. This was nearly the order of decrease in the radii, r′, of the hydrated ions, estimated from hydration enthalpies. An ionexchange mechanism between hydrated K+ ions in the outer Helmholtz layer and hydrated M2+ ions in the solution, suggests positive entropy contributions which offset the endothermic Q. The proposed mechanism is in agreement with the observed sequence of adsorption capacity and with the decrease in Q in the above series, except for Co2+ adsorption (possibly complicated by the oxidation of Co2+ by δ‐MnO2). The adsorption of the cations is probably accompanied by the exchange with Mn ions from the solid. There was evidence of specific adsorption below the point of zero charge (pH 3.3). The adsorption isotherms of Mn2+ ions at pH 7 were higher than those at pH 6 and Q was found to be ‐ 19 kJ mol−1. As the ionic strength increased, the adsorption isotherm of Mn2+ ions at pH 7 and 298 K shifted to lower values. Adsorption isotherms of Cu(II)ions at pH 3.5 and of Fe(III) at pH 2 represent specific adsorption and Q was found to be ‐ 74 and ‐ 13 kJ mol−1 respectively.
The density of an ammonia cloud in the early stages of atmospheric dispersion
Authors: Haddock S. R. , Williams R. J.
Published: July 2010

The variation of the density of a cloud of ammonia vapour and droplets as it mixes with dry or wet air has been examined. This has involved a consideration of the possible chemical and physical interactions of the cloud with the components of the atmosphere, the thermal effects associated with these interactions and the competing processes of evaporation and precipitation of any drops of liquid ammonia that may be present in the cloud. It has been concluded that although pure ammonia vapour even at its normal boiling point is less dense than air under ambient atmospheric conditions, there are circumstances in which a cloud of ammonia dispersing in the atmosphere may be become denser than the surrounding air.
The difficulty of reducing nitrogen oxides in the presence of oxygen
Authors: Van Den Bleek Cornelis M. , Van Den Berg Pieter J.
Published: July 2010

A hypothesis is made, based on the literature, which makes it very unlikely that NO can be selectively reduced by any reducing agent other than ammonia. The hypothesis is based upon the very fast reduction of NO2, even in the presence of oxygen, and an easy reoxidation of NO to NO2which are both preferential to NO reduction in the presence of oxygen. The particular feature of ammonia originates from the fact that in parallel with this reaction, both reactants, under limiting conditions (defined by temperature), participate in a second scheme which leads to the formation of surface complexes dissociating into N2and/or N2O. These surface complexes are most probably NH4NO2and NH4NO3. In the presence of oxygen only this second scheme leads to the formation of N2and or N2O and is even accelerated by the re‐oxidation of NO to NO2.
Fermentation patterns of gramicidin S formation by Bacillus brevis ATCC 9999 in high‐yielding synthetic medium
Authors: Vandamme Erick J. , Leyman Dirk
Published: July 2010

Addition of the gramicidin S (GS)‐constituent amino acids, other than the limiting precursor L‐phenylalanine, to the high‐yielding chemically defined F3/6 and G3/6 media, enhanced growth and volumetric GS‐production by Bacillus brevis ATCC 9999 considerably, but did not yield a higher specific GS‐production level. L‐Leucine alone could duplicate this stimulatory effect in G3/6 medium. Replacing the fructose component of F3/6 medium by these four amino acids yielded a high specific GS‐production level, but resulted in poor growth and low volumetric antibiotic production. Nutrient‐utilisation patterns in F3/6 medium revealed that B. brevis initially grew at the expense of L‐glutamine and L‐arginine. After a diauxic lag period, D‐fructose was consumed together with L‐histidine. L‐Proline was mainly used during the stationary phase. L‐Methionine was broken down gradually throughout the whole fermentation cycle. L‐Phenylalanine was metabolised only after GS formation started, and its disappearance was proportional to the amount of GS produced. Lowering the aeration rate caused an acidification of the medium, resulting in a slower and incomplete, although similar, nutrient‐utilisation pattern. At a controlled pH of 7.3, under lowered aeration, utilisation patterns were again comparable with those of a fully aerated fermentation, but GS levels were enhanced considerably (0.220 mg of GS mg−1 dry cell wt). Depending on environmental culture conditions, B. brevis also excreted different amino acids (L‐lysine, L‐alanine, L‐valine, L‐serine), which were in turn metabolised during late growth and differentiation stages. The onset of GS synthesis occurred on depletion of L‐glutamine and L‐arginine. Soluble GS synthetase 1 and 2 peaks coincided with ‘diauxic’ lag phases; this supported the idea that a high growth rate is incompatible with GS synthetase formation.
Antibiotics from the newly isolated Streptomyces elizabethii. I. Production of a polyene antifungal agent (Elizabethin) and actinomycin in shake flask cultures
Authors: Pirt S. John , Pickett Susan M. A. , Pickett Andrew M. , Vandamme Erick J. , Bird Clive W.
Published: July 2010

A new streptomyces strain, designated Streptomyces elizabethii, was isolated from a soil sample using a method which selected antifungal antibiotic producers. S. elizabethii produces an antifungal polyene (elizabethin) and antibacterial actinomycins. Optimal conditions were elucidated for sporulation of the streptomycete in bottle cultures and for polyene production in shake flask cultures. High sugar concentrations were found to repress actinomycin biosynthesis and increase polyene production. Excess potassium phosphate inhibited polyene production.
Separation of close boiling substituted phenols by dissociation extraction
Authors: Wadekar Vishwas V. , Sharma Man Mohan
Published: July 2010

Some mixtures of substituted phenols, which are difficult to separate by established methods such as distillation, crystallisation, etc., have been separated by dissociation extraction. Di‐n‐butyl ether was found to be an excellent solvent for the systems: phenol‐o‐chlorophenol; p‐chlorophenol‐2,4‐dichlorophenol; o‐cresol‐6‐chloro‐o‐cresol. In the case of m‐cresol‐2,6‐xylenol and p‐cresol‐2,6‐xylenol, benzene was found to be a good solvent. For the system: 4‐chloro‐m‐xylenol‐2,4‐dichloro‐m‐xylenol dissociation extraction in a solid‐liquid system without a solvent gave higher values of separation factor than a liquid‐liquid system. In all the cases, agreement between the experimental and theoretical values of separation factors was found to be reasonable.
Bioleaching of copper from a low‐grade chalcopyrite ore
Authors: Deepak Desh , Das Kumudeswar
Published: July 2010

Experiments conducted in this study provide good evidence that the rate of oxidation of chalcopyrite can be increased many fold by the action of the iron‐oxidising, chemoautotrophic bacteria, Thiobacillus ferrooxidans. Studies were made between the range 28–48°C and between pH 2.0 and 3.5. The optimum temperature and pH were found to be 35°C and 2.7, respectively. Particle sizes of chalcopyrite ore used in the study were between 60 and 190 μm in diameter. The rate of leaching was found to be directly proportional to the decrease in particle size. Supply of air to the system had a pronounced effect on the leaching of chalcopyrite by T. ferrooxidans. During the same period of 48 days, the conversion of copper obtained was 17.8, 58 and 54.4% in stationary, a shake flask and a percolator system, respectively.
Disproportionation of toluene over a metal‐supported type L‐zeolite catalyst
Authors: Halgeri A. B.
Published: July 2010

The disproportionation of toluene was studied using KHL zeolite, with and without metal supports. Incorporation of Ni and Pt to KHL increases significantly the surface acidity and catalytic activity. Their change in surface acidity due to metal‐zeolite interactions predominantly influences disproportionation activity. The performance of metal‐loaded zeolites is also better than that of KHL in terms of initial activity and stability. The effects of the metal, temperature and the carrier gas have been investigated. The bifunctional nature of metal zeolites as represented by the hydrogenation activity of the metallic component and disproportionation activity of acidic zeolites has been established.
The dielectric behaviour of lithium acetylacetonate
Authors: Molokhia N. M. , El‐Shahat M. F.
Published: July 2010

The dielectric constant and loss tangent of lithium acetylacetonate [Li(ac.ac)] have been measured at different frequencies for different temperatures. The results show that the dielectric behaviour of Li(ac.ac) is different from that of Na(ac.ac) and K(ac.ac) which exhibit a ferroelectric‐like behaviour. The activation energy of Li (ac.ac) was found to be 0.54 eV, nearly half the value for K(ac.ac). The infrared absorption spectra of Li(ac.ac) shows that in this compound the lithium metal resembles group II rather than group I.
Physico‐mechanical characteristics of hydrating tetracalcium aluminoferrite system at low water: Solid ratios
Authors: Ramachandran Vangipuram S. , Beaudoin James J.
Published: July 2010

Tetracalcium aluminoferrite (C4AF) mixed with gypsum in amounts of 0, 5, 10, 20 and 30% was hydrated at 25 or 80°C, either as discs (formed at pressures of 140 and 690 MPa to obtain an effective water:solid ratio of 0.08 and 0.13, respectively) or in powder form at water:cement ratios of 0.5 and 1.0. Hydration products formed at periods ranging from a few minutes to 7 days were identified and estimated. The sequence of hydrate formation and the accompanying length changes were also determined. The formation of hexagonal hydrate, cubic hydrate, ettringite, low sulphoaluminate series and their interconversions was primarily dependent on gypsum content, temperature, and initial water:solid (w/s) ratio. The study indicates that ettringite need not necessarily be a precursor of the formation of low sulphoaluminate hydrate when hydration is carried out at a very low w/s ratio at 80°C. The microhardness and porosity characteristics of the hydrated products were compared after 2 days of hydration. The relative contribution of low sulphoaluminate, ettringite, and other hydrated phases on strength development were assessed.
Oxidation products of secondary butyltoluene — a 1H‐n.m.r. study
Authors: Kulsrestha Girendra N. , Joshi Girish C.
Published: July 2010

α‐Primary‐ and α‐tertiary‐hydroperoxides and alcohols, methylacetophenone, s‐butylbenzaldehyde, s‐butylbenzyl ether, and 2‐tolylbut‐2‐ene were identified in s‐butyltoluene oxidates. The quantitative estimates of hydroperoxides and acetophenone by 1H‐n.m.r. compared within ca 2% with those obtained by chemical methods and gas‐liquid chromatography respectively. Unlike chemical methods, the procedure is quick, non‐destructive and unaffected by structural complications.
Study of the heterogeneous reaction between iron and lead oxides
Authors: Vetere Vicente F. , Romagnoli Roberto
Published: July 2010

Different theories are proposed in the literature to explain passivation mechanisms of iron by means of the use of lead compounds. In some cases the protective action is related to the formation of lead soaps with vegetable oils or oleoresinous binders. These soaps are partially dissolved from the film, acting at the interface metallic substrate/paint film. In the case of inert binders (those corresponding to vinyl resins), red lead acts as a passivating agent. The protection of iron plates in the presence of suspensions of red lead, lead monoxide and lead dioxide in a 0.5M sodium perchlorate solution as electrolyte is studied in this paper. Polarisation curves were traced and measurements of voltage at open circuits were made. Only two of the lead oxides tested (red lead and lead monoxide) have corrosion inhibiting action, both showing a similar behaviour.
Ageing studies on some titania gels
Authors: Ragai Jehane
Published: July 2010

Hydrous titania gels, precipitated from titanous chloride and aged in different aqueous media have different textural, thermal and structural properties as demonstrated by nitrogen adsorption, differential thermal analysis, X‐ray diffraction and scanning electron microscopy studies. Ageing in ammonia leads to the development of microporosity, whereas ageing in water causes an extension of the pore system in the primary particles with little change in the surface texture. Heat‐treatment of the precipitated gels prior to ageing seems to afford a certain stability to the primary particle by allowing hydroxo and oxo bridges to be formed, thus leading to the formation of a more rigid structure. The nature of the ageing medium and its effect on the inner coordination sphere of the titanium ions are important parameters affecting the textural and thermal behaviours of the titania gels.
A simplified model for the correlation of vapour‐liquid equilibrium in the CO2‐NH3‐H2O system
Authors: Paunović Ratomir , Petkovska Menka , Krnić Zoran , Ćirić‐Matijević Gordana
Published: July 2010

A new simplified VLE model of the CO2‐NH3‐H2O system under conditions of the distillation and absorption steps of the recycle urea process is developed. For the gaseous phase the virial state equation is adopted and the component activity coefficients are approximated by a simple linear expression. The resulting equations for the equilibrium constants of the physical and chemical equilibria are fitted to experimental values (in the literature) within the temperature range of 307 to 414 K and within the pressure range of 2 to 40 bar. Tests of the model on the experimental data are presented as well as the comparisons with other published simplified VLE models of the system.
Bioactivity of antifouling paints based on organotin toxicants
Authors: Benítez Juan Carlos , Giúdice Carlos A. , Rascio Vicente J. D.
Published: July 2010

This paper discusses the bioactivity of antifouling paints based on organotin toxicants, such as tributyltin fluoride (TBTF) and triphenyltin fluoride (TPTF). These compounds were used alone or mixed as the main toxicant in formulations. The use of TPTF or mixtures of TPTF and TBTF, with vinyl binders, led to paints with satisfactory bioactivity during a 24 months immersion period. With the same binders, TBTF alone provided only 12 months of antifouling protection. The correlation coefficients calculated from the fouling attachment values and the rosin content in the binder showed that the bioactivity of the tested formulations depended on the solubility of the toxicant in sea water and on the composition and solubility of the binders.
The growth behaviour of Azotobacter chroococcum in association with some microorganisms in the soil
Authors: Elwan S. H. , El‐Naggar M. R.
Published: July 2010

An investigation was made on the role of microorganisms in affecting the growth behaviour of Azotobacter in the soil. Azotobacter chroococcum, Bacillus licheniformis, B. megaterium, Pseudomonas striata, Aspergillus niger, A. terreus, A. flavus, A. sydowi, A. nidulans, Fusarium sp., and Helminthosporium sp. were isolated from a sandy neutral soil. This soil was sterilized, one lot was kept as such, and another was supplemented with glucose and potassium phosphates. Azotobacter chroococcum was inoculated alone or in association with any of the above microorganisms. Counts of Azotobacter were made weekly during 14 weeks on nitrogen‐free agar plates.

The results indicated the importance of the microbiological factor in affecting the growth behaviour of Azotobacter in the soil. A general pattern was observed showing a great decline for one week followed by a progressive increase more in non‐supplemented than in supplemented soils. In case of A. niger, however, a tendency of a decline was observed in the last 2 weeks.

The discussion showed that the variation of the microflora of different soils or the nonstationary microbial balance of a soil may contribute to the controversy of the results of the investigations of Azotobacter behaviour in the soil.
Beziehungen zwischen Carboxin‐Resistenz und glykolytischer Potenz bei Pilzen
Authors: Ritter G. , Kluge E. , Lyr H.
Published: July 2010

83 fungal species were tested for their correlation between carboxin sensitivity and glycolytic ability regarding the taxonomic position of the test fungi.

Besides basidiomycetes the ascomycetous orders Helotiales, Sordariales, Chaetomiales, and Dothiorales showed carboxin sensitivity which was coupled with lacking fermentation and acid production while carboxin resistant taxa as a rule behaved vice versa. Furthermore, hexose monophosphate participation was high and phosphofructokinase activity was low in carboxin sensitive fungi.

It is concluded that response to carboxin and glucose metabolism are coupled characters but without strict causal connection. In yeast‐like fungi carboxin sensitivity may indicate their taxonomic position within the basidiomycetes.
Salt stimulated respiration and ion transport of Chlorella fusca
Authors: Löppert H. G.
Published: July 2010

Respiration has been measured in the dark before and after addition of salts to suspensions of Chlorella in distilled water. An immediate and marked, but transient, increase in oxygen uptake rate was observed with several alkali (Na, K, Rb) and heavy metal (Zn, Ce) salts. Comparison of this salt stimulated respiration (S.S.R.) with ion flux rates showed that, in contrast to higher plant cells, with Chlorella no simple relationship exists between S.S.R. and rate of salt uptake. An osmotic effect and direct action of salts with mitochondrial electron transport were excluded as causes of S.S.R. More likely, salt stimulated ATP hydrolysis at the plasmalemma acts upon electron flow to oxygen via respiratory control.
Biochemical studies on sporulation in blue‐green algae II. Factors affecting glycogen accumulation
Authors: Kanta Swarn , Sarma T. A.
Published: July 2010

Inorganic nitrogen sources like nitrate, nitrite enhanced sporulation and glycogen accumulation in Anabaena sp. but ammonium chloride neither influenced sporulation nor glycogen accumulation. Acetate and citrate also stimulated early sporulation and glycogen level was higher over nitrogen free control. Nitrogen and carbon sources in combination proved to be useful in inducing early sporulation and increased content of glycogen. Phosphate and calcium also affected glycogen accumulation significantly, although, the sporulation was found to be of the same order as in nitrogen free medium. Sulphate initiated early sporulation, the mechanism of which is not known.
Determination of a control function in three‐dimensional parabolic equations by Legendre pseudospectral method
Authors: Shamsi M. , Dehghan Mehdi
Published: July 2010

A Legendre pseudospectral method is proposed for solving approximately an inverse problem of determining an unknown control parameter p(t) which is the coefficient of the solution u(x, y, z, t) in a diffusion equation in a three‐dimensional region. The diffusion equation is to be solved subject to suitably prescribed initial‐boundary conditions. The presence of the unknown coefficient p(t) requires an extra condition. This extra condition considered as the integral overspecification over the spacial domain. For discretizing the problem, after homogenization of the boundary conditions, we apply the Legendre pseudospectral method in a matrix based manner. As a results a system of nonlinear differential algebraic equations is generated. Then by using suitable transformation, the problem will be converted to a homogeneous time varying system of linear ordinary differential equations. Also a pseudospectral method for efficient solving of the resulted system of ordinary differential equations is proposed. The solution of this system gives the approximation to values of u and p. The matrix based structure of the present method makes it easy to implement. Numerical experiments are presented to demonstrate the accuracy and the efficiency of the proposed computational procedure. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 74‐93, 2012
Synthesis and characterization of thermoresponsive poly(ethylene glycol)‐based hydrogels and their magnetic nanocomposites
Authors: Meenach Samantha A. , Anderson Kimberly W. , Hilt J. Zach
Published: July 2010

Temperature‐responsive hydrogels are one of the most widely studied types of stimuli‐responsive hydrogel systems. Their ability to transition between their swollen and collapsed states makes them attractive for controlled drug delivery, microfluidic devices, and biosensor applications. Recent work has shown that poly(ethylene glycol) (PEG) methacrylate polymers are temperature‐responsive and exhibit a wide range of lower critical solution temperatures based on the length of ethylene glycol units in the macromer chain. The addition of iron oxide nanoparticles into the hydrogel matrix can provide the ability to remotely heat the gels upon exposure to an alternating magnetic field (AMF). In this work, diethylene glycol (n = 2) methyl ether methacrylate and PEG (n = 4.5) methyl ether methacrylate copolymers were polymerized into hydrogels with 5 mol % PEG 600 (n = 13.6) dimethacrylate as the crosslinker along with 5 wt % iron oxide nanoparticles. Volumetric swelling studies were completed from 22 to 80 °C and confirmed the temperature‐responsive nature of the hydrogel systems. The ability of the gels to collapse in response to rapid temperature changes when exposed to an AMF was demonstrated showing their potential use in biomedical applications such as controlled drug delivery and hyperthermia therapy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3229–3235, 2010
Thiol‐isocyanate‐acrylate ternary networks by selective thiol‐click chemistry
Authors: Matsushima Hironori , Shin Junghwan , Bowman Christopher N. , Hoyle Charles E.
Published: July 2010

Thiol‐isocyanate‐acrylate ternary networks were formed by the combination of thiol‐isocyanate coupling, thiol‐acrylate Michael addition, and acrylate homopolymerization. This hybrid polymerization reaction sequence was preferentially controlled by using phosphine catalyst systems in combination with photolysis. The reaction kinetics of the phosphine/acrylate thiol‐isocyanate coupling reactions were systematically investigated by evaluating model, small molecule reactions. The thiol‐isocyanate reaction was completed within 1 min while the thiol‐acrylate Michael addition reaction required ∼10 min. Both thiol‐isocyanate coupling and thiol‐acrylate Michael addition reactions involving two‐step anionic processes were found to be both quantitative and efficient. However, the thiol‐isocyanate coupling reaction was much more rapid than the thiol‐acrylate Michael addition, promoting initial selectivity of the thiol‐isocyanate reaction in a medium containing thiol, isocyanate, and acrylate functional groups. Films were prepared from thiol‐isocyanate‐acrylate ternary mixtures using 2‐acryloyloxyethylisocyanate and di‐, tri‐, and tetra‐functional thiols. The sequential thiol‐isocyanate, thiol‐acrylate, and acrylate homopolymerization reactions were monitored by infrared spectroscopy during film formation, whereas thermal and mechanical properties of the films were evaluated as a function of the chemical composition following polymerization. The results indicate that the network structures and material properties are tunable over a wide range of properties (Tg ∼ 14–100 °C, FWHM ∼ 8–46 °C), while maintaining nearly quantitative reactions, simply by controlling the component compositions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3255–3264, 2010
Thermal stability of porous it‐PMMA thin film obtained by the extraction of st‐PMAA from it‐PMMA/st‐PMAA stereocomplex with layer‐by‐layer assembly on a substrate
Authors: Ajiro Hiroharu , Maegawa Masumi , Akashi Mitsuru
Published: July 2010

The functionality of porous isotactic (it) poly(methyl methacrylate) (PMMA) thin films, which were previously developed by the selective extraction of syndiotactic (st) poly(methacrylic acid) (PMAA) from the it‐PMMA/st‐PMAA stereocomplex thin film on a substrate using the layer‐by‐layer assembly method was investigated after thermal treatment (70, 80, and 90 °C) in water for 4 h. Quartz crystal microbalance analysis and infrared spectra measurements revealed that the st‐PMAA incorporation ability of the porous it‐PMMA thin film decreased in order at 80 and 90 °C, while there was no decrease observed at 70 °C. X‐ray diffraction analysis also supported the thermal stability of the porosity at 70 °C, whereas two it‐PMMA crystalline peaks (2θ = 9° and 14°) were generated during heating at 90 °C. The loss of the functionality of the it‐PMMA thin film was thus shown to be due to crystallization, which was caused by the increase in polymer‐chain mobility during the heating process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3265–3270, 2010
Synthesis of polymer microspheres functionalized with chiral ligand by precipitation polymerization and their application to asymmetric transfer hydrogenation
Authors: Haraguchi Naoki , Nishiyama Akihiro , Itsuno Shinichi
Published: July 2010

Monodisperse, crosslinked poly(divinylbenzene) and poly(methacrylic acid‐co‐ethylene glycol dimethacrylate) microspheres with (1R,2R)‐N1‐toluenesulfonyl‐1,2‐diphenylethylene‐1,2‐diamine ((R,R)‐TsDPEN) moiety were successfully prepared by precipitation polymerization. Introduction site of the (R,R)‐TsDPEN moiety into the polymer microspheres could be controlled by changing the order of addition of the corresponding monomers. The functionalized polymer microspheres were applied to asymmetric transfer hydrogenation of ketone and imine. Polymer microsphere‐supported chiral catalysts showed good reactivity and enantioselectivity in the catalytic asymmetric transfer hydrogenations. Chiral secondary alcohol was quantitatively obtained with 94% ee in the asymmetric transfer hydrogenation of acetophenone in water. We also found that introduction site of the chiral catalyst and hydrophobicity of the microspheres, as well as degree of the crosslinking, affected the yield and enantioselectivity of chiral product in this reaction. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3340–3349, 2010
Synthesis, characterization, and properties of amphiphilic chitosan copolymers with mixed side chains by click chemistry
Authors: Yuan Weizhong , Zhao Zhengda , Gu Shuying , Ren Jie
Published: July 2010

Novel amphiphilic chitosan copolymers with mixed side chains of poly(ε‐caprolactone) and poly(ethylene oxide) (CS‐g‐PCL/PEO) were successfully synthesized by “graft to” approach via click chemistry. The melting and crystallization behaviors and crystalline morphology of CS‐g‐PCL/PEO copolymers can be adjusted by the alteration of the feed ratio of PCL and PEO segments. CS‐g‐PCL/PEO copolymers revealed crystalline morphology different from that of linear alkynyl PCL and alkynyl PEO due to the influence of brush structure of copolymers and the mutual influence of PCL and PEO segments. The hydrophilicity of the CS copolymers can be improved and adjusted by the alteration of the composition of PCL and PEO segments. Moreover, the CS copolymers can self‐assemble into spherical micelles in aqueous solution. Investigation shows that the size of the CS copolymer micelles increased with the increase of the content of hydrophobic PCL segments in copolymers, which indicated that the micellar behavior of the copolymers can be controlled by the adjustment of the ratio of PCL and PEO segments in copolymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3476–3486, 2010
Thermoelasticity and conformational behavior of polyethylene and ethylene‐propylene copolymers
Authors: Opschoor A. , Prins W.
Published: July 2010

Force‐temperature measurements at constant length and pressure are reported for amorphous, crosslinked networks of polyethylene and some ethylene‐propylene copolymers. The ratio of the energy contribution to the total tension, fe/f, calculated from these measurements and thermal expansion data, was found to depend strongly on the extension ratio as well as on the crosslink density. In current theory fe/fT is equal to the temperature coefficient of the unperturbed mean‐square end‐to‐end distance of the polymer chain in the network (d In (r02)/dT). The experimentally found nonconstancy of the fe/f makes it impossible to calculate a single value of d In (r20)/dT) for comparison with our a priori calculations of this quantity. These findings are at variance with previously published data of Flory, Ciferri, and Hoeve. Possibly, stress‐induced crystallization or, more generally, stress‐dependent intermolecular forces may play a role in thermoelas‐ticity studies under certain circumstances, in spite of the reversibility of the temperature cycles.
The decomposition mechanisms of xanthates of model compounds for cellulose. I. Xanthates of primary, secondary, and tertiary alcohols
Authors: Joedodibroto Roehjati , Rånby Bengt
Published: July 2010

Xanthates of methanol, ethanol, isopropanol and t‐butyl alcohol were prepared and purified. The decomposition of these xanthates in aqueous alkali solutions (NaOH and KOH) at different temperatures was studied by UV spectrophotometry at 300‐303 nm. The methyl, ethyl, and isopropyl xanthates decomposed without salt effect and showed increasing stability in this order. They appeared to decompose by a bimolecular reaction (addition of a hydroxyl ion to the xanthate group) according to an Sn2 mechanism. The t‐butyl xanthate decomposed at a much faster rate and with salt effect, apparently by a monomolecular reaction (dissociation of the xanthate to a t‐butyl carbonium ion and a dithiocarbonate ion) according to an Sn1 mechanism. The decomposition behavior of these model xanthates cannot explain the previous findings that xanthates of primary alcohols (e.g. on cellulose chains) are more stable than xanthates of secondary alcohols.
Fracture of polymers in biaxial and triaxial tension
Authors: Smith Thor L.
Published: July 2010

Macroscopic fracture is preceded by localized deformation and rupture processes that depend on the state of combined stress (i.e., on the stress state) and other test conditions as well as on polymer structure and morphology. To illustrate the effect of stress state on the mode of fracture initiation and crack growth, data obtained on elastomers in triaxial tension are reviewed along with those for an unfilled styrenebutadiene rubber vulcanizate in simple tension, equal biaxial tension, and under the biaxial tensile conditions that give a pure shear deformation. The behavior of plastics, including the dependence of the strength of a notched specimen on its thickness, is briefly considered.
Structural changes of drawn polyacrylonitrile during annealing
Authors: Hinrichsen Georg
Published: July 2010

Fibers and solvent‐cast films of polyacrylonitrile have been investigated by x‐ray small‐angle and wide‐angle measurements and dynamic‐mechanical analysis. It has been found that the structure of this polymer is better described by a two‐phase model consisting of more and less ordered regions. By the aid of x‐ray methods, transition temperatures have been observed; there are indications that the molecules within the ordered regions are responsible for motion mechanisms. By annealing, the colloidal structure and thereby the mechanical behavior is influenced.
RAMEA: how to support regional policies towards sustainable development
Authors: Sansoni Michele , Bonazzi Elisa , Goralczyk Malgorzata , Stauvermann Peter J.
Published: July 2010

A Regional Accounting Matrix including Environmental Accounts (RAMEA) is the Regional version of a ‘National Accounting Matrix including Environmental Accounts’ (NAMEA), an environmental accounting system that combines economic and environmental accounts into a single framework, which is useful for the evaluation and comparison of the integrated economic–environmental–social performance of regions. Presenting the first results of compiling and applying a RAMEA in three European regions: Emilia‐Romagna (Italy), Noord‐Brabant (the Netherlands) and Małopolska (Poland), this paper analyses the difficulties in achieving internationally comparable regional models. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Hearing loss in Pompe disease revisited: results from a study of 24 children
Authors: van Capelle Carine I. , Goedegebure Andre , Homans Nienke C. , Hoeve Hans L. J. , Reuser Arnold J. , van der Ploeg Ans T.
Published: July 2010

Little information is available regarding the auditory function in Pompe patients. Hearing loss has been reported in classic infantile patients, but it is still unknown whether central nervous system involvement interferes with auditory function and whether enzyme replacement therapy can improve hearing. Auditory function has not been studied in children with milder forms of the disease. We analyzed repetitive auditory brainstem response measurements and pure tone audiometry in 24 children with Pompe disease. Only 1 of 13 patients with milder phenotypes showed recurrent conductive hearing loss, while 10 out of 11 classic infantile patients had sensorineural hearing defects. These patients also had a high prevalence of conductive hearing loss. Five patients showed evidence of mild retrocochlear pathology, suggestive of glycogen accumulation in the central nervous system. Hearing loss persisted during therapy in all patients. The results emphasize the need for careful monitoring of auditory function in classic infantile Pompe patients, and for early implementation of hearing aids to protect speech and language development.
Conservation study of Myrsine seguinii in Japan: current distribution explained by past land use and prediction of distribution by land use‐planning simulation
Authors: Vega Luis A. , Koike Fumito , Suzuki Makoto
Published: July 2010

The causes of the current distribution of a warm temperate tree Myrsine seguinii population were studied from topographic, geographical, and historical perspectives, and future land management to conserve this species. The study site is the Tokyo University forest located in Chiba Prefecture, at the northern distribution limit of this species. Presence and absence of individuals was surveyed in 10 × 10 m plots along the census line, making a total of 9,697 plots. The current distribution was modeled by multivariate logistic regression using environmental variables determined based on 10‐m mesh digital elevation model (elevation, slope, solar radiation, topographic wetness index, surface curvature), 1‐km mesh climatic information, and current (2005) and historic (1900) land‐use maps. It was clarified that the current distribution area coincides with a Pinus densiflora forest present by the end of the 19th‐century Meiji era, where 88.6% of individuals of M. seguinii were found. Inland suitable areas show small patches distributed among the ridges and mountainsides facing south, decreasing as the average monthly minimum winter temperature decreases. Simulated scenarios showed that in the future the potential distribution area of the studied species would decrease in the case of a complete coverage of Cryptomeria or Chamaecyparis plantation, and the case of evergreen broadleaf forest coverage would be better than these plantations. The strong effect of past land use suggests vulnerability and difficulty in the rapid recovery of M. seguinii population from human disturbance.