bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parameters affecting adsorption of microorganisms on activated charcoal cloth
Authors: George Neil , Davies John T. 
Published: July 2010

AbstractAn experimental apparatus and protocol has been developed in which adsorption of microorganisms to activated charcoal cloth and the influence of various physicochemical parameters, including the effects of externally applied electrical potential, was examined. Unlike Langmuir‐type isotherms which were obtained when Ecoli adsorption was studied in revolving universal tubes, in the stirred cell described here multilayer isotherms were produced. The differences in adsorption trends were possibly due to differences in the hydrodynamic environment. Although under certain conditions long‐range electrostatic and electrodynamic forces seemed to influence adsorption, under the standard experimental conditions used, strong, nonbiological, close‐range interactions were occurring and cation bridging was implicated. Electrical polarisation of the activated charcoal cloth surface did not influence adsorption within the limits examined. Electrochemically induced aggregation in conditions where pH varied was observed, which was enhanced in the presence of MgSO4 and was associated with a precipitated material which appeared to bridge between the bacteria and the activated charcoal surface.
Dissolution kinetics of an oxidized copper ore in water saturated by chlorine
Authors: Ekmekyapars Ahmet , Clolak Sabri , Alkan Mahir , Kayadeniz Ilker 
Published: July 2010

AbstractDissolution kinetics of an oxidized copper ore (mainly malachite) in water saturated by Cl2 has been studied. The effect of particle size, flow rate of the gas, temperature and solid‐liquid ratio has been determined. The dissolution rate increased with decrease in particle size and solid‐liquid ratio and with increase in the gas flow rate and temperature. It has been found that the dissolution proceeds in two stages and is controlled by diffusion through the ash layer in each stage. The activation energies for the first and second stage are 27.15 and 20.21 kJ mol−1, respectively.
Isolation of high‐purity zirconia from Australian zircon sands using an ion‐exchange process
Authors: Ooi Choon W. , Hobday Malcolm D. , Bentata Albert 
Published: July 2010

AbstractZirconia produced by acid‐leaching zircon sand can be significantly contaminated by other elements leached from the sand. A simple cationexchange procedure has been developed that allows separation of the impurity elements from the zirconium to give zirconia with up to 99.99% purity. The addition of formic acid to the acid‐leach solution prior to ion exchange provides the removal of about three‐quarters of the hafnium present in the product zirconia.
Changes in intracellular sodium and potassium in chemostat‐cultivated Escherichia coli
Authors: Ratwatt Hiran A. M. , Wase D. A. John 
Published: July 2010

AbstractEscherichia coli was continuously cultivated at constant dilution rate for a range of agitation rates, and at constant agitation rate over a range of dilution rates. Mean cell volume increased linearly both with increase in agitation rate (as we have previously found) and with increase in dilution rate. In each case, measurement of intracellular sodium and potassium content after rapid separation of cells from the medium by centrifugation through silicone oil showed these to increase as the mean cell volume increased. In absolute terms, the increase in sodium or potassium per unit cell volume was significantly greater for changes in agitation rate than for changes in dilution rate.
New approaches to the development of viral vaccines: Scientific and regulatory aspects
Authors: Robertson James S. 
Published: July 2010

AbstractThe revolution in biotechnology in the 1980s raises the possibility of producing vaccines which were hitherto difficult or impossible to produce by classical techniques. This revolution must be met by parallel considerations of appropriate evaluation and control procedures to ensure the safety and efficacy of such new vaccines. A significant problem of these new approaches is the difficulty in identifying a suitable subunit component able to induce a satisfactory protective immune response in the host. In addition vaccines produced in unusual cell substrates may contain contaminants not previously encountered by man. These and other problems are being met by the application of many of the control measures found useful in the past, by evaluation of all manufacturing processes, by the formulation of guidelines by international groups of experts, and by free international exchange of information on new problems of control as they arise.
The assessment of real hazards and appropriate counter‐measures: The clinician's view
Authors: Freestone D. S. 
Published: July 2010

AbstractBiologicals whether or not produced by biotechnological techniques comprise a heterogeneous collection of substances which are derived from natural organisms or cells, or equivalent substances produced by synthesis, which are assayed by biological methods. These substances are used for various purposes in medicine and may be divided into three principal groups; vaccines, sera (including immunoglobulins and monoclonal antibodies) and biologically active proteins.General concerns specific to the safety of biological products relate to possible adverse immunological interactions and the presence of contaminants: particularly viruses and bacteria, nucleic acids, and ‘additives’. Additives include impurities derived from the manufacturing and purification processes and materials deliberately added as preservatives or adjuvants. Each biological product demands individual review but in making assessments special consideration is needed of the extent of batch to batch variability and whether studies to confirm the absence of any increased frequency of neoplasia as a consequence of nucleic acid contamination should be pursued.In the future more biologically active proteins will be produced including some which differ from natural proteins in being more specific in activity, of greater potency or with a different pattern of distribution metabolism and excretion. These and new monoclonal antibodies may interact immunologically with host tissues in unexpected and undesirable ways and demand the application of new specific preclinical and clinical screens.The need for post marketing surveillance studies of an appropriate scale is no less for biologicals than for defined chemical entities.
Public perception of biotechnology hazards
Authors: Tait Joyce 
Published: July 2010

AbstractSo far the public reaction to new biotechnology industries has been largely benign, at least in the UK, but it is questionable how deeply held and how stable this attitude is. Biotechnology has some features in common with classic risk related issues, like nuclear power and pesticides, and could provoke an equally adverse public response.This paper examines what we currently know about perceptions of biotechnology with the conclusion that the ‘public’ has yet to make up its mind. Factors that could influence the future public response include: rural social disruption caused by further increases in the productivity of agricultural land; any failure to control the new technology effectively, leading to a loss of public trust in the regulatory system; and intrinsic moral and ethical issues surrounding genetic manipulation, particularly in higher animals.
Oxide films on iron and iron‐copper alloys: An imaging atom probe investigation
Authors: Cornell Rochelle M. , Smith George D. W. , Cranstoun G. K. L. 
Published: July 2010

AbstractAn imaging atom probe has been used to analyse the oxide films formed by room‐temperature oxidation and atmospheric rusting on iron and on an ironcopper alloy. Both rusted and oxidised specimens field evaporated as Fe2+ Fe+, O+, FeO+ and FeO2+. In addition, hydroxylated iron species field evaporated from rust. Exposure of the specimen to sulphate ions during rusting led to incorporation of sulphate in the rust. Oxide films grown on the iron‐copper alloy were enriched in copper. Cu+ and Cu2+ field vaporated from this oxide, but CuO species were not detected. All the oxide films examined consisted of a mixture of amorphous iron hydroxide and magnetite. It is suggested that the copper in the oxide film may have been present as a substitutent in the magnetite lattice.
Effects of temperature and moisture on the anaerobic digestion of refuse
Authors: Kasali George B. , Senior Eric 
Published: July 2010

AbstractThe influence of the first‐tier variable temperature on the anaerobic decomposition of refuse was investigated by use of laboratory models. Temperature was found to exert significant effects on the interrelated metabolic processes of acidogenesis, solventogenesis and methanogenesis. A temperature elevation from a mean ambient regime (18.7°C) to 30°C resulted in a 2.6‐fold increase in the methanogenic rate while a 7.8‐fold increase was observed when the temperature was raised from 18.7 to 40°C. The rate of methanogenesis at 40°C was approximately three‐fold higher than at 30°C. Further temperature elevation to 55°C, however, resulted in the cessation of methanogenesis although solventogenesis was promoted. An attempt was made to extrapolate the results obtained to actual landfill, with specific reference to the role of refuse density in thermogenesis.
Mixing time in bioreactors
Authors: Kawase Y. , Moo‐Young M. 
Published: July 2010

AbstractThe mixing time in bioreactors is discussed. Theoretical correlations for the mixing time in stirred tank and bubble column reactors respectively, are derived. They are based on Kolmogoroff's theory of isotropic turbulence and the relationships between the mixing time and the axial dispersion coefficient in the turbulent flow regime. The predictions of the proposed correlations are in reasonable agreement with several available data and correlations. A wide divergence among the data for the mixing time reported in the literature is also discussed.
Microbial sensors: Fundamentals and application for process control
Authors: Riedel Klaus , Renneberg Reinhard , Wollenberger Ulla , Kaiser Gabi , Scheller Frieder W. 
Published: July 2010

AbstractMicrobial sensors consist of microorganisms in intimate contact with transducer devices converting the biochemical reaction to a quantifiable electrical response signal. The aim of this combination is the sensitive determination of a large spectrum of substances in various fields, especially in fermentation processes and pollution control. Microbial sensors for more than 50 different parameters have been described in the literature.In this paper, the following main aspects are discussed: microbial and physical basis of microbial sensors, immobilization of microbes, principle of measurement, approaches for enhancing the selectivity and sensitivity of microbial sensors, applications in bioreactor and environmental control of microbial sensors.
Inhibition of phosphine liberation from amorphous red phosphorus
Authors: McCallum John J. , Alder John F. 
Published: July 2010

AbstractAn extensive study of the liberation of phosphine from commercial red phosphorus was undertaken. The influence of water, trace metals, magnesium, calcium and aluminium oxides and a selection of carbamates, phenols and quinones was investigated. Accelerated ageing tests at 50°C were used to assess the value of 1% (w/w) additions of p‐benzoquinone and 1,4‐naphthoquinone in particular, as inhibitors to the generation of phosphine from commercial phosphorus and a pyrotechnic composition including spindle oil and poly(vinylbutyral). The two quinones suppress the liberation of phosphine to < 5% the rate of generation from commercial unoiled phosphorus. The mechanism of phosphine generation is obscure, but involves dissociation of water in the phosphorus surface region and the formation of phosphorus acids which may disproportionate yielding phosphine. Alternatively, or simultaneously, hydrogenation of phosphorus may take place liberating phosphine. The quinones presumably arrest these processes by preferentially combining with hydrogen or free‐radical intermediates. The use of silver‐nitrate‐impregnated charcoal cloth and granules to remove gaseous phosphine was also studied.
Estimation of crystalline phase in ZSM‐5 zeolites by infrared spectroscopy
Authors: Shukla Dipak B. , Pandya Vyomesh P. 
Published: July 2010

AbstractA fast and accurate method for identification and determination of purity of Zeolite Socony Mobil 5 (ZSM‐5) zeolite was developed using the IR optical density ratio of the bands at 550 and 450 cm−1 in the mid‐IR region of the structure spectra. The optical density values obtained from the proposed method, for ZSM‐5 zeolite synthesized, are compared with those of the Bayer ZSM‐5 zeolite used as reference material. For well‐crystallized calcined ZSM‐5 zeolite, this ratio is circa 0.8. This ratio is found to be less, if amorphous silicate is present in zeolite. The presence of a band at 550 cmSUP>−1 in addition to the one at 450 cm−1 shows that ZSM‐5 zeolite has been formed even if the material is X‐ray amorphous. The absence of the structure‐sensitive band at 550 cm−1 unambiguously indicates that such a zeolite has not been formed.
Effect of Carrier Matrix on Fermentative Production of Ethanol by Surface Immobilised Yeast Cells
Authors: Passarinho Paula C. L. V. , Vieira Ana M. S. , Cabral Joaquim M. S. , Novais JúLio M. , Kennedy John F. 
Published: July 2010

AbstractThe production of ethanol for potable preparations is well established and the traditional methods used therein are changing. More important, however, has been the advent of fuel alcohol, first in Brazil, but now with ever‐increasing possibilities of being adopted in North America and Europe. Production of alcohol by fermentation has therefore come to stay, and it is essential to discover ways of improving the productivities of such fermentations.The effect of organic (cellulose and corn stover) and inorganic matrices (silica gel, porous silica, Celite and derivatised Celite) on the performance of ethanol fermentation by Saccharomyces bayanus was tested. The hydrophilicity degree of the support seems to play an important role in the ability of reaching high ethanol concentrations in the fermentation of 300 g dm−3 of glucose. Cells immobilised on carriers with low hydrophilicity degree, namely Celite, lead to better results (residual glucose: 56 g dm−3; ethanol: 111 g dm−3) than their free counterparts (residual glucose: 136 g dm−3; ethanol: 71 g dm−3).Celite was selected for further cell immobilisation studies, including time of adsorption, whole cell concentration, initial glucose concentration and time of addition of the support to the fermentation medium. The latter has revealed to be a very important factor, improving the performance of ethanol fermentation by reducing the fermentation time. Previous immobilisation seems to have no effect when compared with the simple addition of Celite to the inoculated medium and the eficiency of Celite did not increase when the concentration of glucose was enhanced.
Aerobic treatment of branched alkylbenzene sulfonates
Authors: Hashim M. A. , Kulandai J. 
Published: July 2010

AbstractBranched alkylbenzene sulphonates, recalcitrant xenobiotic compounds, were treated aerobically in a single‐tank activated‐sludge reactor and also by means of three continuous‐stirred‐tank reactors (CSTR) in series. For the single‐tank reactor it was observed that, the longer the hydraulic retention time, the greater were the reductions in biological oxygen demand (BOD), chemical oxygen demand (COD) and methylene blue active substances (MBAS). Reductions of 80%, 60% and 63% were achieved in the levels of BOD, COD and MBAS, respectively. In the case of the three‐CSTR system, acclimatization of the microorganisms was achieved 15 days after start‐up. For this system, the reductions in the levels of BOD, COD and MBAS were 80%, 68% and 69%, respectively.
Macrokinetics and mathematical modelling of quinone reduction by cyanobacteria
Authors: Kreysa G. , Krämer P. 
Published: July 2010

AbstractThe kinetics of the reduction of externally added 2‐hydroxy‐1,4‐naphthoquinone by blue‐green algae of the strains Anabaena PCC 7120 and Anacystis nidulans PCC 6301 were studied in aqueous cell suspensions by electrochemical monitoring of the concentration of the formed hydroquinone. This reaction is of potential interest for bioelectrochemical fuel cells. The experimental curves obtained could be interpreted by a model that takes into account that both substrate and product have to be transported through the microbial cell walls and that the conversion reaction takes place with firstorder kinetics within the microbial cells. No clear evidence was found for the involvement of photosynthesis. It is suggested that the reduction of the quinone probably occurs via the enzyme‐catalyzed oxidation of endogenous storage product(s), presumably glycogen.
Diffusion rates in a dense matrix of methane‐producing microorganisms
Authors: Nilsson Britt K. , Karlsson Hans T. 
Published: July 2010

AbstractThe diffusion rate of a species, in a dense matrix of methane‐producing microorganisms, was determined experimentally. To this end, a specially designed diaphragm diffusion cell was utilized. The experimental results revealed that the effective diffusion coefficient in a microorganism matrix was 22–33% of the diffusion coefficient in pure water.
Heterocyclic hansa yellow analogues: Synthesis of novel azodisperse dyes from 3‐oxo‐N‐(pyrazol‐4‐yl) butanamide as possible dyes for polyester fibres
Authors: Girges M. M. , Hanna M. A. , Elagamey A. A. 
Published: July 2010

AbstractDifferent heterocyclic Hansa Yellow analogues were synthesized from 3‐oxo‐N‐(pyrazol‐4‐yl)butanamide for possible use as azodisperse dyes for dyeing polyester fibres. The free energy relationship between the position of absorption of these dyes‐λ‐and substituent Hammett sigma constants was investigated.
Nickel extraction from a nickel‐tungsten spent catalyst using column leaching
Authors: Kelebek S. , Distin P. A. 
Published: July 2010

AbstractNickel extraction from an uncrushed spent nickel‐tungsten catalyst was studied using sulphuric acid leaching in a column. The effects of flowrate, temperature and acid concentration on the cumulative nickel recovery was investigated using a three‐variable, two‐level factorial design. Statistical analysis indicated that among these variables only acid concentration was significant (at the 95% confidence level) in the ranges investigated. The catalyst can be leached either by a two‐step process or in a single step following catalyst preoxidation. In either case extractions exceeding 95% can be obtained. With oxidized samples, single‐step acid leaching at 82°C yielded significantly better nickel extraction than at 95°C. This was attributed mainly to tungstic acid precipitation in the catalyst pellets, an effect which occurs rapidly at 95°C and retards the leaching of nickel. Nickel extraction was also suppressed following preoxidation at over 300°C. This was thought to be due to formation of slow‐leaching nickel oxide‐tungstate. Following preoxidation at the optimum of 300°C, 97% of the nickel could be leached in 4 h at 82°C using (by volume) 3% sulphuric acid and 0.6% nitric acid flowing at 1.5 litres/h. About 70% of the nickel could be extracted from preoxidized catalyst using only water for 40 h at room temperature. These findings are incorporated in a simple proposed flowsheet.
Anaerobic sludge digestion using mesophilic‐thermophilic phase separation
Authors: Chang Tan C. , Wu Yeun C. , Ouyang Chua F. , Hao Oliver J. 
Published: July 2010

AbstractPhase separation of sludge digestion was investigated using a suspended growth system for the acid phase and a fixed‐film system for the methane phase. A thermophilic temperature of 50°C was used in the methane reactor, while a mesophilic temperature of 37°C was maintained in the acid reactor. During the acid‐phase stage, the volatile acid concentration and the reduction of volatile solids averaged approximately 2200 mg dm−3 as acetic acid and 13% (w/v), respectively, under a hydraulic retention time of 2 days. These parameters were not significantly affected by the applied solids concentration. Reduction of the retention time in the acid reactor from 2 days to 1 day decreased the methane content (18% versus 28%) and the volatile solids destruction (8% versus 13%), but produced the same amount of volatile acids. The total gas production for 10 days overall retention time was slightly higher than that for conventional single‐phase sludge digestion. The significant cost saving in reactor volume and enhanced methane production may offset the increased energy consumption required for maintaining a thermophilic temperature during the methane phase.
Hydrodynamics of the flow transition from a bubble column to an airlift‐loop reactor
Authors: Verlaan Paul , Vos Jan‐Chris , Van T Riet Klaas 
Published: July 2010

AbstractThe hydrodynamics of an airlift‐loop reactor (ALR) and a bubble column (BC) were studied in the same reactor unit. When the liquid circulation in the ALR was impeded gradually in order to obtain a BC mode of operation, there was a transition flow regime inbetween that of the ALR‐type flow and the BC‐type flow. In the BC the heterogeneous flow was represented by an instationary circulatory flow pattern and characterized by a liquid circulation velocity. The liquid flow in the ALR was represented by a drift‐flux model. In the transition flow regime, hydrodynamic calculations based on the plug‐flow behavior of an ALR appeared to be valid up to a certain defined value of the total gas‐liquid flow rate. To distinguish between BC and ALR flow characteristics, a simple criterion is proposed, qualifying that the distinction between both flow patterns is determined by the superficial liquid velocity and the liquid circulation velocity. If the latter velocity exceeds the superficial liquid velocity a hydrodynamic transition will occur from a uniform ALR type of flow to a heterogeneous BC type of flow. The criterion coincides with an empirical power law function in which the liquid velocity is given as a function of the gas velocity. The values of the power‐law coefficients depended on the characteristics of the two‐phase flow. The change in value cohered with the onset of a change in the flow pattern.
Use of dimensionless parameters in design of cascade‐connected reactors
Authors: Muslu Yilmaz 
Published: July 2010

AbstractGeneral relationships applicable to a wide variety of bacterial mediated wastewater treatment processes have been developed using continuous‐flow stirred‐tank reactors (CSTR) arranged in series. Monod kinetics and mathematical models of reactors‐in‐series were used to represent the actual conditions resulting from varying degrees of axial dispersion and wastewater qualities. A numerical method was developed and effluent concentrations from an equivalent reactor series expressed based upon a plug‐flow reactor with the same inlet and outlet conditions. Using the numerical results obtained, a nomogram has been derived that enables the required hydraulic and solids residence times for a reactor with a given dispersion number to be determined, when inlet and outlet conditions and the coefficients of Monod kinetics are known.
Spectrophotometric determination of zinc in some aluminum base alloys
Authors: Zaki M. Tarek M. , Ragheb Abdel‐Ghani , Mohamed Adel S. 
Published: July 2010

AbstractThe complexation of zinc with hematoxylin was studied in the presence and absence of cetyltrimethylammonium bromide (CTAB). The sensitivity of the color reaction between zinc and hematoxylin was significantly increased by the sensitizing action of CTAB. The optimum range of pH for complex formation was 7.3±8.0. The molar absorptivity of the complex was 6.3 × 104 liter mol−1 cm−1 at 610 nm and Sandell's sensitivity was 0.001 μg cm−2. Beer's law was obeyed up to 0.92 μg of zinc per ml. To determine zinc in aluminum base alloys, a preliminary solvent extraction separation of zinc from 2M hydrochloric acid solution with tri(iso‐octyl)amine in isobutyl methyl ketone was carried out.