bluuebunny/crossref_metadata_2025_split huggingface dataset:
Food preservation: An example of the application of negative biotechnology
Authors: Jarvis B. , Paulus K. 
Published: July 2010

AbstractThe processing of foods to ensure the availability for the consumer of a wide variety of safe stable products provides a good example of the application of ‘negative biotechnology’. The objectives are to optimise the use of food resources by reduction or elimination of spoilage and waste, control food‐borne health problems and develop ‘new’ food products. Our work describes the way in which technology is applied to control of biological, chemical and physical changes in foods. Examples are given to illustrate the implications for product shelf‐life of the various process operations including inter alia, thermal and irradiation treatments, restriction of available water, use of chemical preservatives and the choice of packaging systems. Special emphasis is placed on the need to optimise quality and safety by the proper application of kinetic data for the various process operations. The concepts of quality assurance, ‘in‐line’ process control and the use of microprocessor technology in the control of critical processes is considered. The work concludes with a look at the future requirements of the food processing industry in relation to developments in ‘negative’ biotechnology.
Strain improvement in antibiotic‐producing microorganisms
Authors: Normansell Ian D. 
Published: July 2010

AbstractIn the context of commercial strain development for improved antibiotic production it is important to stress the efficiency and practicability of the procedures used. Typical constraints are the novelty of the microorganism, time and manpower. Established and more novel techniques applied to strain improvement can be divided into the induction of beneficial alterations and the screen for and recognition of such altered mutants. Recent advances have contributed mainly to the former of these two divisions. The empiricism of mutagenesis can be removed as more is known about mutation induction with respect to repair phenomena. Mutagens must be assessed for efficiency with rapid test systems for forward and reverse mutation. Enhanced mutation frequencies can be achieved with repair‐deficient mutants or chemical inhibitors of repair processes. It is widely accepted that recombinational methods are an important part of strain development although published examples of its successful application are rare. Parasexuality in asexual fungi and protoplast fusion in both bacteria and fungi facilitate recombination and therefore the construction of improved strains. As a result of these advances it has become necessary to deviate from the classical, linear mutation and selection programmes. The application of recombinant DNA technology to strain development is undoubtedly promising. In the field of antibiotic research this approach may necessitate extensive basic research before its potential can be realised. Major constraints may be poor knowledge of both the biosynthesis of the antibiotic and the genetic systems in the producing microorganism. It will also be necessary to develop suitable vector systems. This approach clearly consumes time and resources which are important considerations in commercial terms. The ability to recognise and isolate improved mutants is just as important as their production and again time and efficiency is paramount. Shake‐flask screening has been central to most programmes although its format may be changing to accommodate multiline screens to capitalise on recombination techniques. Its major limitation as a primary screen is in the work involved in testing a comparatively small number of strains. To circumvent this problem many laboratories are miniaturising screens or moving towards ‘plate‐based’ screens in which colony productivity is assessed on agar. Plate screens also permit less empirical screening procedures such as reversion of mutants impaired in antibiotic production or the use of chemical inhibitors of antibiotic biosynthesis. This approach has the advantage of allowing large numbers to be screened as well as providing information of a biosynthetic nature if the mutants and inhibitors are subject to investigation in their own right.
Environmental factors influencing the growth of animal cells in culture
Authors: Birch John R. , Cartwright Terence 
Published: July 2010

AbstractAn analysis is made of environmental factors controlling growth rate and maximum population density of cultured mammalian cells. Three factors may limit maximum population density: accumulation of an inhibitor, exhaustion of essential nutrients or availability of surface for growth. Whilst the significance of inhibitors is uncertain, examples are given of nutrient exhaustion limiting maximum population density. Growth of anchorage‐dependent cells is influenced by both available surface area and by the physicochemical properties of the surface. Finally examples are given of ways in which environmental terms may interact, often in complex fashion, to modify cell growth.
Cultivation of anchorage‐dependent cells and their applications
Authors: van Wezel A. L. 
Published: July 2010

AbstractA short review and evaluation of the various cultivation systems for anchorage‐ dependent cells is given. From the cultivation systems presently available the micro‐carrier culture system might be considered to be the most suitable system for large‐scale cultivation of these cells. Beside its high potential for scaling up and control of environmental conditions, it has the advantage of easy separation of cells and culture medium. This facilitates medium changes either batch‐wise or continuously. For continuous refreshment the sieve for retaining the beads with cells in the fermenter should be built on the stirrer shaft in order to avoid blocking.
Hydrogenation of benzene to cyclohexene on a ruthenium catalyst: Physical and chemical characterisation of the catalyst and its precursor
Authors: Ingemar Odenbrand C. U. , Andersson S. Lars T. 
Published: July 2010

AbstractThe chemical and physical characteristics of a ruthenium catalyst used in the hydrogenation of benzene to cyclohexene has been investigated. The active catalyst consists of metallic ruthenium obtained by hydrogen reduction of the precursor suspended in the alkaline aqueous phase. The precursor consists of hydrous oxides of ruthenium with a surface area of 27 m2 g−1. After reduction the surface area increases to 112 m2 g−1 and a drastic change in pore‐size distribution occurs. The average pore diameter decreases from 28 to 13 nm and the number of pores < 8 nm increases substantially. The macroscopic particle size, in the range 25–40 μm, decreases along with the decreasing ruthenium concentration. Poisoning of the catalyst by corrosion products, mainly hydroxides of iron and chromium, is also discussed.
On the importance of dimension variation in determining the limiting steps in adsorption kinetics
Authors: Kärger Jörg , Bülow Martin , Ulin Vladimir I. , Voloshchuk Albert M. , Zolotarev Pavel P. , Kočiřik Milan , Zikánová Arlette 
Published: July 2010

AbstractInformation about the limiting processes in adsorption kinetics can be obtained by an analysis of the shape of the uptake curves (first and second statistical moments M1 and M2) as well as by an analysis of the dependence of the adsorption time constants on the radii (R) of the adsorbing particles. The sensitivity of these dependences on the various models of adsorption has been investigated by introducing the factors M12/M2 and d ln M1/d ln R. d ln M1/d ln R‐2 is shown to be a reliable criterion for diffusion‐limited adsorption. From the shape of M12/M2 no corresponding criterion can be derived.
Study of multicycle melting and freezing of sodium thiosulphate pentahydrate
Authors: Stunić Zlatko , Djuričković Veljko , Majstorović Slobodan , Buljan Vlado 
Published: July 2010

AbstractThe behaviour of sodium thiosulphate pentahydrate in the course of repeated use as a heat‐storing medium can be predicted, cycle by cycle, on the basis of a generalised phase‐transition equation adapted for incongruently melting material. An indice is derived for this purpose and named ‘coefficient of true phase‐transition reversibility’. Its predictive value is shown for three additional incongruently melting materials well known as heat‐storing media: CaCl2.6H2O, Na2SO4.10H2O and the mixture Na2SO4.10H2O + 2/3NH4Cl + 2/3NaCJ.
Synthesis and biological activity of new β‐lactam and thiazolidinones containing a sulphanilamide moeity
Authors: Hassan Khairy M. , El‐Shafei Ahmed K. , El‐Kashef Hussein S. , Mashaly Mohamed M. 
Published: July 2010

AbstractSome new sulpha drugs containing both β‐lactam and/or thiazolidinone moieties have been prepared. The biological screening of the prepared compounds has been carried out on some strains of pathogenic bacteria. It is clear that these compounds have a different mechanism of action other than that already known for the sulpha drugs.
Electrochemical treatment of effluents from adipic acid plants
Authors: Cox David A. , El‐Ghaoui Elias A. , Ellis Keith G. , Jansson Robert E. W. , Meissner Dieter 
Published: July 2010

AbstractElectrochemical measurements have been made on the system Cu2+‐adipic acid‐HNO3 (which models the effluent from adipic acid plants) to investigate the reasons for the observed low current efficiency for copper deposition from such solutions. The most probable cause is a cathodic shift in the deposition potential of copper making the reduction of NO3− the preferred process. Depletion experiments have been carried out on real effluent in two three‐dimensional cells, a bipolar trickle tower and a porous reticulated carbon bed. Each performs reasonably well and, while the current efficiencies are low (c 20%), the deposition is essentially mass‐transfer controlled.
Syntheses of dihydrolavandulol and its related compounds from carboxylic acids and conjugated dienes
Authors: Fujita Tsutomu , Watanabe Shoji , Suga Kyoichi , Miura Toshiro , Sugahara Kotoji , Kikuchi Hajime 
Published: July 2010

Abstract5‐Methyl‐2‐isopropyl‐4‐hexenoic acid, dihydrolavandulic acid (III), was synthesised in 65% yield from 3‐methylbutanoic acid and isoprene with sodium naphthalenide in the presence of N,N,N′,N′‐tetramethylethylenediamine. Reduction of III with lithium aluminum hydride gave 5‐methyl‐2‐isopropyl‐4‐hexen‐l‐ol, dihydrolavandulol (IV) (85% yield). Oxidation of IV with pyridinium chlorochromate gave 5‐methyl‐2‐isopropyl‐4‐hexenal, dihydrolavandulyl aldehyde (V) (81 % yield).
Polarographic reduction of some oxazolones at the dropping mercury electrode
Authors: Fahmy Hussein M. , Daboun Hamed A. , Hussein Mona M , Elnagdi Mohamed H. 
Published: July 2010

AbstractThe polarographic behaviour of a series of 4‐arylidene‐2‐phenyl‐2‐oxazolin‐5‐one derivatives over a wide range of pH is reported and discussed. A mechanism for the electrode process is elucidated and confirmed via isolation and characterisation of electrolysis products.
Hydrogen‐gas production with Citrobacter intermedim and Clostridium pasteurianum
Authors: Brosseau James D. , Zajic J. E. 
Published: July 2010

AbstractCitrobacter intermedius and Clostridium pasteurianum were grown in 14‐dm3 batch reactors on glucose and measured for biomass and H2 production. Gas production with C. intermedius was found to be growth related, whereas that with C. pasteurianum was entirely produced during the stationary phase of growth. The maximum yield and productivity of H2 with C. intermedius was 60% H2 or 1 mol of H2 mol−1 of glucose at a maximum of 3.7 mmol of H2 h−1 and 85% H2 or 1.5 mol of Ha mol−1 of glucose at a maximum of 9.0 mmol of H2 h−1 with C. pasteurianum. The overall H2 productivity (QH2) was 2.5 mmol of H2 h−1 g−1 dry biomass for C. pasteurianum at a glucose concentration of 7.6 g dm−3. As the glucose concentration was increased from 7.6 to 15.4 g dm−3, up to 44% of the gas produced with C. pasteurianum was growth associated. The remainder of the gas was produced in the stationary phase. In this case the overall Ha productivity (QH2) was 1.2 mmol of H2 h−1 g−1 dry biomass. The comparative experiments indicate that maximum yields and rates of H2 production were achieved with C. pasteurianum.
Effect of some aromatic hydroxy sulphonic acids on uptake of acid dyes by nylon 6
Authors: Guthrie John , Cook Christopher C. 
Published: July 2010

AbstractThe major constituents of a synthetic tanning agent for leather, prepared from the condensation of a naphthol sulphonic acid with formaldehyde, have been separately synthesised and have been shown to be of low molecular weight. The effect of these ‘syntan components’ on the uptake of four acid dyes by nylon 6 has been studied as has the desorption of the agents during the uptake of dye. Although the components have only a minor effect on the rate at which dye is adsorbed by the fibre, they reduce the extent to which dye is taken up at equilibrium. The restraining effect observed is governed by the affinity of both dye and agent. It is concluded that unlike commercial syntans which are available for the aftertreatment of dyed nylon, the products studied diffuse readily into the polymer matrix and, after application to nylon, are not held firmly at the fibre surface.
Crystallisation of pentaerythritol. III. Impurity distribution coefficients
Authors: Simons Terrence J. , de Silva Rohan L. , Creasy Dennis E. 
Published: July 2010

AbstractCommercially available pentaerythritol usually contains di‐pentaerythritol, a formal and formaldehyde as impurities. The distribution coefficients of these impurities were measured on crystallising pentaerythritol from aqueous solution at temperatures of 30, 50 and 70°C. It was found that di‐pentaerythritol did not co‐precipitate with pentaerythritol. The formal readily co‐precipitates and crystallisation will only yield purification if carried out above 90°C. Purification from formaldehyde was achieved readily and only at temperatures below 10°C should the product be less pure. The free energy of the transfer was found to be approx.‐40 kJ mol−1 in both cases.
Effect of trace impurities on calcium sulphate precipitation
Authors: Sarig Sara , Mullin John W. 
Published: July 2010

AbstractInduction periods for the precipitation of CaSO4.2H2O in the concentration range 0.05‐lM have been determined by the stopped‐flow method utilising changes in the solution conductivity after nucleation and growth. The measured induction periods were insensitive to calcium sulphate concentration, suggesting that the nucleation process was heterogeneous. At first additions of Al3+ increasingly prolonged the induction period, but above a certain Al3+ concentration further additions caused the induction period to reduce again. Tentative explanations based on the poisoning of growth sites by [Al(H2O)6]3+ complexes for the first effect and the deaquation of aluminium complexes followed by formation of polymeric species for the second are given. It is suggested that the small crystallites which appeared on the surfaces of the gypsum crystals precipitated in the presence of relatively high fluoride concentrations are CaF2.
Effects of biocide and nutrient availability on microbial contamination of surfaces in cooling‐water systems
Authors: Miller P. C. , Bott T. R. 
Published: July 2010

AbstractThe results of an evaluation of the effects of different factors on formation, growth and removal of biological films are reported. Experiments have been performed both on laboratory equipment and a test system located on a cooling‐water system at an industrial site.The effects of temperature, nutrient availability and surface material of construction are discussed in relation to film formation. Experiments concerning continuous biocide treatment are assessed in relation to biofilm removal. A pure culture of Pseudomonas fluorescens was used to grow biological films in the laboratory under identical hydrodynamic conditions but at different temperatures. Drastic reductions in film thickness were noted at temperatures 5°C above and below the optimum temperature for growth of the organism. The effects of nutrient loading under similar hydrodynamic conditions have been studied in the laboratory. The maximum biofilm thickness was reduced by 55% when no air was present and by 80% when neither air nor nutrient were supplied. Biofilm growth at the industrial site was unexpectedly more pronounced on brass than mild steel. Examination of destruction of existing biofilms in the laboratory showed that at a concentration of 4 parts 10−‐6 free chlorine (sodium hypochlorite) the initial rate of film removal was four‐to‐six times higher than that at 2.5 parts 10−‐6 free chlorine. A higher velocity of sodium hypochlorite solution over the biofilm resulted in a higher rate of removal. The results are discussed in the light of published data in related tests.
A comparison of Nylon‐66‐supported platinum and palladium catalysts for the hydrogenation of 1‐octyne in the liquid phase
Authors: Bowden Colin , McLellan Richard J. , Macdonald Ronald P. , Winterbottom John M. 
Published: July 2010

AbstractA number of Nylon‐66 fibre‐supported platinum (Pt) catalysts were prepared by refluxing solutions of ammonium chloroplatinite with Nylon‐66 fibres. The resulting Pt‐Nylon‐66 catalysts were used for the hydrogenation of 1‐octyne in n‐propanol and n‐heptane at 70°C and 1 atm. total pressure. They, like their palladium (Pd) counterparts, exhibited solvent sensitivity in respect of their selectivity for 1‐octyne production. However, both activity and selectivity trends, as metal concentration increased, were different from those exhibited by Pd‐Nylon‐66 catalysts. Pd‐Nylon‐66 catalysts gave an activity maximum, whereas Pt‐Nylon‐66 catalysts did not, activity increasing with metal concentration. Both catalysts gave constant selectivity, independent of metal concentration in n‐heptane (Pd‐Nylon‐66 = 0.99–1.00; Pt‐Nylon‐66=0.75–0.76).In n‐propanol Pd catalysts gave high selectivity (0.99–1.00) for low metal concentrations. Pt‐Nylon‐66 catalysts exhibited the opposite tendency, giving low selectivity (0.46–0.50) at low metal concentrations and higher selectivity (0.75–0.76) at high metal concentrations. It is concluded that, whereas Pd‐Nylon‐66 catalysts exist as some form of Pd(II) complex over a wide concentration range, Pt‐Nylon‐66 only exists as a complex at low concentrations and becomes predominantly zero‐valent (metallic) Pt supported on the Nylon‐66 at higher concentrations.
Sorption of caesium by complex hexacyanoferrates: II. X‐ray crystallography and mössbauer spectroscopy of sodium‐copper cyanoferrates (II)
Authors: Bennett B. A. , Shahbandeh M. R. , Streat M. 
Published: July 2010

AbstractX‐Ray diffraction patterns and Mössbauer spectra of sodium‐copper cyanoferrate(II) (NaCuFC) before and after incorporation of caesium atoms have been studied. The positions of the X‐ray reflections and the symmetry of the Mössbauer spectra suggest that NaCuFC has a cubic lattice structure which remains cubic as caesium atoms are introduced. Calculations based on the assumption that the lattice is face‐centred cubic, with high‐symmetry space group Fm3m, enable the distribution of atoms and vacancies to be estimated. In the case of iron atoms, 33 % of the corner sites are vacant in the sodium compound. The isomer shift data obtained by Mössbauer spectroscopy suggest that the sorption of caesium is not a simple ion‐exchange process. It may be regarded as ‘pseudochemisorption’ resulting from augmentation of 3d orbitals and/or the contribution from 4s bonding.
Synthesis of furoates and 5‐nitrofuroates in cyclohexane in the presence of cation‐exchange resins
Authors: Bigot Yves Le , Ayedi Hacine Ferid , Delmas Michel , Gorrichon Jean‐Pierre , Gaset Antoine 
Published: July 2010

AbstractThe use of ion‐exchange resins for the esterification of furoic acid and 5‐nitrofuroic acid was characterised by an excellent yield and the absence of side reactions, particularly when the reaction was carried out in cyclohexane in the presence of the resin, SPC 118. The use of this solvent for such a reaction in a biphasic medium is thus reported for the first time. This procedure might therefore be considered on a larger scale.
Effect of calcium oxide on the hydration of calcined by‐product gypsum
Authors: Beretka Julius , Crook Douglas N. , King George A. 
Published: July 2010

AbstractThe effect of adding increasing amounts of calcium oxide (CaO) in the pH range 3–11 on the rate of hydration and physical properties of calcined by‐product gypsums from four Australian locations was examined. The results were interpreted in terms of the Ridge equation. It was found that, as pH increased by the addition of small quantities of CaO, the kinetic parameters changed greatly. In particular, the velocity constant k gradually decreased, while α0, the measure of heterogeneous nucleation, increased. In general, increases in pH resulted in longer setting times but little change in water requirement. The mechanical strength of cast by‐product gypsum increased with the addition of CaO up to about pH 7–8, then decreased in the alkaline region. Below about pH 7 the kinetics of hydration of the hemihydrates were in close accordance with the model developed by Ridge, but differed from it above pH 7–8. This may be due to poisoning of the gypsum nuclei by habit modifiers, which are present in small quantities in by‐product gypsum.
Quantitative measurement of the percentage of aromatic carbons in petroleum crudes by using 13C‐nuclear magnetic resonance spectrometry
Authors: Srivastava Shanti P. 
Published: July 2010

AbstractQuantitative 13C‐nuclear magnetic resonance has been applied to the determination of the percentage of aromatic carbon atoms (% CA) of Nahorkatia, Ankleshwar (both Indian) and Basrah (Middle‐Eastern) crude oils. From the analysis of these results it has been demonstrated that a combination of the instrumental and chemical methods (gated decoupling with a relaxation reagent added) is the only satisfactory method for the precise determination of % CA The maximum deviation in % CA due to nuclear Overhauser effect has also been estimated.
Solar‐energy storage with quadricyclane systems
Authors: Behr Arno , Keim Wilhelm , Thelen Gerhard , Scharf Hans‐Dieter , Ressler Ingrid 
Published: July 2010

AbstractNorbornadiene derivatives are able to store solar energy under isomerisation to a quadricyclane system. This energy can be liberated by a transition‐metal catalysed back reaction. With methanol as a solvent during the isomerisation of dimethylquadri‐cyclanedicarboxylate I to the dimethylnorbornadienedicarboxylate II the isomeric nortricyclylmethylethers IIIa and IVa are formed as by‐products. In the presence of water the formation of the alcohols IIIb and IVb has been observed. As a result of the side‐reactions observed, it is concluded that this solar‐energy storage system I→II offers no practicability.
Decomposition of aziridine (ethyleneimine) and N‐acetylaziridine in aqueous solution
Authors: Clifford‐King William , Ferrige Anthony G. , Torkington Peter 
Published: July 2010

AbstractThe decompositions of ethyleneimine (EI) and its N‐acetyl derivative (AEI) have been studied in aqueous buffers at concentrations down to 1 mM. The course is determined by pH dependence, of two alternative reactions for AEI and of two consecutive reactions for EI. Consistent kinetic systems are presented. One of the reactions of AEI is a hydrolysis to EI, not reported previously. The rate‐determining step for EI decomposition is initial dimerisation to N‐(β‐aminoethyl)‐aziridine.