bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of the energetic parameters associated with the aerobic degradation of quinoline by Comamonas acidovorans in continuous culture
Authors: Solomon Bamidele Ogbe , Hecht Volker , Posten Clemens , Deckwer Wolf‐Dieter
Published: May 2005

An estimation of the true growth yields and maintenance coefficients for Comamonas acidovorans DSM 6426 under continuous cultivation on quinoline has been performed. The data were checked for consistency using available electron, carbon and nitrogen balances. The true biomass energetic yields, ηmax, and energetic maintenance coefficients, me, were estimated using two models based on control of growth rate and control of substrate uptake rate, respectively. The estimations were converted to the various familiar true growth yield and maintenance units such as substrate‐based (Y, mS/X), oxygen‐based (Y, m) and carbon dioxide‐based (Y, m) units. For the complete mineralization of quinoline by C. acidovorans, values of ηmax = 0.371 and me = 0·0426 h−1 were obtained.
Electrooxidation of dyestuffs in waste waters
Authors: Allen Stephen J. , Khader Kayed Y. H. , Bino Murad
Published: May 2005

An electrochemical oxidation cell is used to reduce the concentrations of organic dyes and chemical oxygen demand in an aqueous effluent. The importance of the presence of an electrolyte is recorded and the effects of changing both electrolyte concentration and initial dye concentration are reported. The rate of the electrooxidation process is shown to be a pseudo‐first‐order kinetic process with the rate constant being affected by both the electrolyte concentration and the dye concentration. The use of different electrolytes is reported.
Adsorption of Pb2+ on blast furnace sludge
Authors: Lopez Felix A. , Perez Carlos , Sainz Enrique , Alonso Manuel
Published: May 2005

An evaluation of the applicability of blast furnace sludge, generated during the purification of blast furnace gases, as an adsorbent to remove heavy metals from industrial effluents is presented. The influence of residence time and temperature on the adsorption efficiency of the sludge is studied for the particular case of Pb2+. The adsorption data, which fit the Langmuir equation well, show that the blast furnace sludge has a high adsorption capability, up to 80 mg Pb per g dried sludge at saturation. The order of magnitude of the adsorption enthalpy, calculated from the apparent equilibrium constant, indicates that the adsorption of Pb2+ on the sludge is of a physical nature. XPS and EDAX analysis suggest that the physical adsorption process partially occurs through ionic exchange between Pb2+ and other ions such as Ca2+. Techniques exist for the recovery of metallic iron and either metallic lead or lead oxide from the sludge. The rendering of sludge into pellets, followed by their controlled heating, allows not only the extraction of these metals, but also makes use of the coke within the sludge. These techniques are clearly interesting alternatives to the dumping of this toxic and hazardous waste.
Epoxidized polyurethaneamide and polyesteramide as petroleum pipeline coatings
Authors: Motawie Ahmed Magdy , Hassan El‐Said Ali , Manieh Atef , Aboul‐Fetouh Mostafa , El‐Din Ashraf Fakhr
Published: May 2005

Linseed oil fatty acids were epoxidized by peracetic acid, then reacted with diethanolamine to give epoxidized hydroxy ethyl linseed oil fatty acid amide (I). This amide was rejected with toluene diisocyanate to produce epoxidized polyurethane‐amide (II). Component I was also reacted with phthalic anhydride to give epoxidized polyesteramide (III). Resins II and III were evaluated as coating materials. The results obtained were compared with commercial epoxy resin, and show that resins II and III may be suitable to use as petroleum pipeline coatings.
Structure–basicity relationships for pyridine extractants
Authors: Szymanowski Jan , Borowiak‐Resterna A. , Voelkel A.
Published: May 2005

Topological indices are determined for models of prospective pyridine extractants and the relationships structure–topological index and topological index–pyridine nitrogen basicity are described. The second order valence molecular connectivity index, the Balaban index and the Wiener number are appropriate structural descriptors of pyridine derivatives and, in several cases, permit the pyridine nitrogen basicity to be predicted. The relationships between pKa values and the structural descriptors are given and described.
Catalysis by superacidic zirconia: Transalkylation of di‐isopropylbenzene with benzene and substituted benzenes
Authors: Suresh R. , Rajadhyaksha R. A. , Kumbhar P. S.
Published: May 2005

The transalkylation reaction of di‐isopropylbenzene with benzene and substituted benzenes over sulphate‐treated superacidic zironia catalyst was studied. The catalyst was found to show comparable activity to that of zeolite and acid‐treated clay (Filtrol‐24). However, it was found to deactivate because of the heavy compounds in the starting reaction mixture and coke formation.
Chemical degradation of aldicarb in water using ozone
Authors: Beltrán Fernando J. , Alvarez Pedro M. , Legube Bernard , Allemane Hellene
Published: May 2005

The use of ozone to degrade aldicarb in water was investigated under different conditions. The oxidation develops through the direct attack of ozone since the presence of hydroxyl radical inhibitors, such as tert‐butanol, does not affect the degradation rate of aldicarb. The combination of ozone with hydrogen peroxide does not improve the oxidation rate which also confirms the absence of radical reactions to eliminate aldicarb. However, TOC removal increases 51% in the presence of hydrogen peroxide after 65 min of oxidation. The oxidation rate is strongly affected by the type of device for feeding ozone, which indicates that a fast gas‐liquid reaction is taking place. Therefore, mass transfer and chemical reaction steps are important factors in the establishment of the global rate of oxidation. Application of kinetic equations derived from gas absorption theories allows the determination of the rate constant of the direct ozone–aldicarb reaction, which was found to be: k = 3·18 × 1011 exp(–6000/T) m3 mol−1s−1.
Influence of the gas—liquid separator design on hydrodynamic and mass transfer performance of split‐channel airlift reactors
Authors: Choi Keun H. , Chisti Yusuf , Moo‐Young Murray
Published: May 2005

Three geometric configurations of gas–liquid separators were used in split‐channel airlift reactors (0·1 m3 liquid volume; riser‐to‐downcomer cross‐sectional area ratio = 0·7; aspect ratio = 3.6) to test the effect of geometry on hydrodynamic performance and oxygen transfer behaviour. For otherwise fixed conditions, the design of gas–liquid separators affected the induced liquid circulation rate, the depth of penetration of the bubble layer in the downcomer, the gas holdup in the downcomer, the mixing time and the overall volumetric gas–liquid oxygen transfer coefficient. The gas holdup in the riser was only marginally affected by the design of the separator. The impact of the various separator designs on hydrodynamic behaviour could be explained as emanating from a combination of the gas–liquid separating ability of the design and its hydraulic resistance.
Enzymatic resolution of 1‐ferrocenylethanol and 1‐ferrocenyl‐2,2,2‐trifluoroethanol using lipases
Authors: Izumi Taeko , Aratani Satoshi
Published: May 2005

1‐Ferrocenylethanol and 1‐ferrocenyl‐2,2,2‐trifluoroethanol were resolved with transesterification by lipases to the optically active (R)‐esters and (S)‐alcohols. Enzymatic hydrolysis of the racemic esters of 1‐ferrocenylethanol using lipases yielded (R)‐alcohol and (S)‐esters. Enantioselective hydrolysis of racemic acetate or butanoate of 1‐ferrocenyl‐2,2,2‐trifluoroethanol yielded the (S)‐alcohol and (R)‐esters. Enzymatic hydrolysis of (±)‐acetate of 1‐ferrocenyl‐2,2,2‐trifluoroethanol yielded (R)‐alcohol and (S)‐acetate, but the equivalent (±)‐butanoate was not hydrolyzed.
Aqueous solutions of hydrotropes as effective reaction media for the synthesis of 4‐aryl‐1,4‐dihydropyridines
Authors: Sadvilkar V. G. , Khadilkar B. M. , Gaikar V. G.
Published: May 2005

The condensation of benzaldehydes with acetoacetic esters and ammonia was carried out in aqueous solutions of aliphatic hydrotropes. Substantial enhancement in the rates of the reactions along with easy recovery of the product were noted. The recyclabilty of the hydrotropes has also been tested.
Molecular transport characteristics of a chlorosulfonated polyethylene geomembrane in the presence of aromatic esters
Authors: Aminabhavi T. M. , Munnolli R. S.
Published: May 2005

Results of a study on sorption and diffusion of chlorosulfonated polyethylene geomembrane with methyl benzoate, ethyl benzoate, methyl salicylate, iso‐butyl salicylate, phenyl acetate, and diethyl phthalate in the temperature range 25–60°C are presented. A gravimetric sorption method is used to calculate the diffusion and permeation coefficients from the Fickian relationship. The diffusion results are dependent on penetrant–membrane interactions, temperature, and on penetrant concentration. The values of diffusion coefficients range from 0·02 × 10−7 cm2 s−1 for diethyl phthalate at 25°C to 1·81 × 10−7 cm2 s−1 for ethyl benzoate at 60°C. The activation energies for diffusion range from 21 to 50 kJ mol−1. The values of heat of sorption ranged between 2·2 and 6·4 kJ mol−1. Sorption results are also analyzed using a first‐order sorption kinetic equation. Experimental results and calculated parameters are used to discuss the transport behavior. None of the esters used have shown any chemical attack toward the geomembrane.
Study of water repellent effect of earth substrates impregnated with water‐based silicones
Authors: Ren Kebao , Kagi Douglas A.
Published: May 2005

As part of a study to assess the efficacy of impregnation for masonry materials, the impregnation of earth substrates with soluble sodium silicate followed by water‐based silane/siloxane emulsion was investigated. The treatment was found to be successful in achieving water repellent and consolidation effects for the earth substrates. The water repellent effect is developed by the silane/siloxane emulsion which forms a polysiloxane thin film on the capillary wall surface through siloxane bonds. The water repellent effect is greatly enhanced by pre‐impregnation with the silicate. The consolidation of the earth substrate by soluble sodium silicate is caused by the silicate gel formed by crosslinking with the substrate. The water repellent and consolidation effects in the earth substrates have been studied by using water absorption tests and FTIR examination.
Biosorption of heavy metals by Saccharomyces cerevisiae: Effects of nutrient conditions
Authors: Engl Andrea , Kunz Benno
Published: May 2005

Studies took place to investigate the effects of different nutrient conditions on the biosorption ability and selectivity of heavy metals by Saccharomyces cerevisiae. After having grown in media supplemented with additional glucose, ammonium, phosphate or cysteine, the yeast was exposed to an equimolar solution of lead, cadmium, zinc and copper. Lead removal from a mixed solution was significantly higher than that of copper, followed by zinc and cadmium. Generally, yeasts from cysteine‐rich media showed greatest sorption capacity whereas phosphate addition influenced zinc selectivity. In addition, glucose, fructose and sucrose as carbon sources were examined. Cultures grown in glucose had a better uptake than those cultivated with fructose at an incubation time of 30 min.
Selective manipulation of only one of two similar sites within a molecule ‘odin reactions’: Strategic advantage for synthesis and tactics available
Authors: Milner David J.
Published: May 2005

Approaches used to effect selective reaction at one of two or more similar sites in a molecule are reviewed. The nature of the problem is defined and the strategic advantage to be gained through the use of symmetrical intermediates is outlined early and re‐emphasised throughout the discussion with specific examples of multistage syntheses of important products. The various tactics used to effect site selectivity in a late synthetic step are described in a logical sequence and presented in a form aimed to help in the design of syntheses of unsymmetric products from symmetric intermediates.
Biological and integrated chemical–biological treatment of PCB congeners in soil/sediment‐containing systems
Authors: Aronstein Boris N. , Rice Laura E.
Published: May 2005

A series of experiments was conducted on the integrated chemical–biological treatment of 14C‐labelled polychlorinated biphenyl congeners in soil/sediment‐containing systems. The hydroxyl radicals, generated by Fenton's reagent (1% (v/v) H2O2, 1 mmol dm−3 FeSO4), followed by inoculation with Pseudomonas sp., strain LB400, and Alcaligenes eutrophus, strain H850, increased the overall extent of 2‐chlorobiphenyl mineralisation in slurries of contaminated manufactured gas plant soil and sediment by 2·9 and 7·4 times, respectively, compared with biodegradation alone. In uncontaminated topsoil slurries the effect of chemical pretreatment was not observed. In the systems amended with 2,2′,4,4′‐tetrachlorobiophenyl, the application of Fenton's reagent increased the overall extent of mineralisation by 2·4 times, compared with the biological treatment alone, but had no effect in the slurries of contaminated soil and sediment. The increased level of radioactivity in the liquid phase of experimental systems suggests that intermediates produced in the process of chemical oxidation are less hydrophobic than parent polychlorinated biphenyls and therefore more available for further biodegradation.
A novel multienzyme electrode for the determination of citrate
Authors: Gajovic Nenad , Warsinke Axel , Scheller Frieder W.
Published: May 2005

A novel amperometric biosensor for the determination of citric acid in food samples and fermentation broths has been developed. The sensor is composed of citrate lyase (CL, EC 4.1.3.6), oxaloacetate decarboxylase (OAC, EC 4.1.1.3) and pyruvate oxidase (POP, EC 1.2.3.3), co‐immobilized in gelatin, and an amperometric transducer. A Clark‐type O2‐electrode and a modified Clark‐type H2O2‐electrode were alternatively used as a transducer. The biosensor covers a linear detection range from 1 μmol dm−3 to 1 mmol dm−3 citrate, with a response time of 2·5 min for the steady state response. The lower detection limit for citrate is 0·5 μmol dm−3. The response of the sensor remained constant for 8 days and decreased to 25% after 18 days at 20–23°C. The results obtained from citrate determinations in food samples and fermentation broths agree well with those determined by enzymatic sample anlaysis. The relative standard deviation for citrate determinations with the new biosensor was 2·2% (n = 7).
Performance enhancement with tapered anaerobic fluidized‐bed bioreactors
Authors: Wu Chun‐Sheng , Huang Ju‐Sheng
Published: May 2005

The substrate removal efficiencies of the conventional (taper angle of 0°) and three tapered anaerobic fluidized‐bed bioreactors (tape angles of 2·5°, 5° and 10°) predicted from a kinetic model correlated with the average biofilm thickness measured. The predicted substrate removal efficiencies of the three tapered bioreactors were higher than that of the conventional bioreactor. This result was also confirmed by the experimental study, implying the performance of the conventional bioreactor can be significantly enhanced by changing the geometrical configuration to a tapered form. Moreover, the rate‐limiting step of acetate methanogenesis in the bioreactors was reaction‐controlled and the biofilm was fully‐penetrated.
Activated sludge treatment of wash waters derived from the purification of virgin olive oil in a new manufacturing process
Authors: Borja Rafel , Alba José , Banks Charles J.
Published: May 2005

Effluent derived from the washing of virgin olive oil in a new manufacturing process was found to be readily treated using a completely mixed activated sludge process. The biokinetic coefficients for the process were derived by operating laboratory‐scale plant at four different input chemical oxygen demand (COD) concentrations and four differing solids retention times. Results showed effluent COD to be correlated with input feed growth and proportional to the product of feed strength and specific growth rate. The proportional to the product of feed strength and specific grown rate. The multiple‐substrate model of Admas et al. fitted the data well and could be used productively to determine effluent COD from a wide range of input substrate concentrations.
Removal of the tetravalent actinide thorium from solution by a biocatalytic system
Authors: Young Ping , Macaskie Lynne E.
Published: May 2005

The aim of this work was to study the effects of pH, a metal complexing reagent (citrate) and the concentration of substrate on the bioaccumulation of tetravalent actinides, using Th4+ as a model, by a phosphates‐catalysed reaction. This yields HPO which precipitates with heavy metals as cell‐bound metal phosphate. Poor removal of The from solution was observed, which is in accordance with the solution chemistry of the metal. A considerable improvement in the efficiency of thorium removal was obtained by incorporating ammonium acetate (NH4Ac) into the solution. Although extensive deposition of polycrustaling NH4UO2PO4 was observed previously by cells that had accumulated UO, no evidence for deposition of cstalline thorium phosphate was obtained by X‐ray diffraction analysis. Examination by proton induced X‐ray emission (PIXE) analysis. Examination by proton induced X‐ray emission (PIXE) analysis showed a non‐homogenous thorium deposit of variable phosphorous content.
The swelling of a low‐rank coal in benzene–pyridine and toluene–pyridine mixtures
Authors: Jones J. Clifford , Prawistasari Bayu
Published: May 2005

A low‐rank coal is examined for swelling in benzene–pyridine and toluene–pyridine mixtures. In each case, swelling is shown to mainly due to the pyridine, the action of which is specific and not amenable to interpretation by the solubility parameter approach to understanding coal swelling.
Contrasting adsorption exhibited by lignite‐based activated carbons
Authors: Allen Stephen J. , Balasundaram Vikram , Armenante Piero M. , Thom Linda , Kafkewitz David
Published: May 2005

The adsorption of sodium benzoate, 2,4‐dichlorophenol and 2,4,6‐trichlorophenol onto five activated carbons made from Northern Ireland lignite is reported. A Two‐stage process consisting of chemical activation during the charring of the lignite, followed by steam activation was used to produce the activated carbons. The adsorption equilibrium isotherms obtained for the carbons have been plotted to obtain the Freundlich, Langmuir and Redlich Peterson constants. Chemical and steam activation methods both produced improvements to the carbon performance on their own, with the combination of the two treatments providing the best results. In the main the chemical treatment providing the best improvement on its own also gave the biggest improvement when combined with steam treatment. BET surface area measurements made using nitrogen adsorption correlate strongly with the capacity for benzoate adsorption.
Additives from aromatic extracts
Authors: Mohamed Mohamed M. , El Naga Hamdi H. Abou , El Meneir Mohamed F.
Published: May 2005

Aromatic extract residues, as by‐products, are accumulated in local refineries through the refining of lubricating oils. These residues are dealt with as low economic value products, even their disposal imposes serious problems to the refineries. Therefore, the present work is aimed at upgrading these residues by using them to synthesis some different petroleum additives, e. g. antioxidants, ashless dispersant additives, pour point depressants and flow improvers for crankcase lubricating oils and fuels. Antioxidants are synthesised by reacting mono‐aromatics with phosphorus pentasulphide (P2S5) in the presence of zince oxide (ZnO). Ashless dispersant additives are synthesised by reacting alkylated mono‐aromatics (using chlorinated paraffin wax as alkylating agent) with formaldehyde solution (37%) in the presence of polyisobutylene succinimide. Pour point depressants and flow improvers are synthesised by acylating di‐aromatics via a Friedel‐Crafts' reaction. Comparative evaluation of the performance of the synthesised products with commercial additives showed their good efficiency.
Separation of phenylacetic acid, 6‐aminopenicillanic acid and penicillin G with electrodialysis under constant current
Authors: Chen Dong‐Hwang , Wang Sung‐Shyong , Huang Ting‐Chia
Published: May 2005

The separation behavior of phenylacetic acid (PAA), 6‐aminopenicillanic acid (6‐APA) and penicillin‐G (Pen‐G) with electrodialysis under constant current was studied. The effects of ionic concentrations and current density on their separation behavior were investigated. The sorption of PAA, 6‐APA and Pen‐G and in the anion exchange membrane, and the variations of the applied voltage and current efficiencies with time during electrodialysis were also examined. It was found that the molecular size and the affinity toward the anion exchange membrane played a key role for the electrodialysis of PAA, 6‐APA and Pen‐G. Phenylacetic acid had the lowest affinity toward the membrane but the fastest transport rate. Penicillin‐G had the highest affinity toward the membrane but the slowest transport rate. With the increase of Pen‐G concentration, the concentration polarization of Pen‐G in the vicinity of anion exchange membrane became very serious, which severely retarded the transport of PAA and 6‐APA. Although the increase of current density accelerated the transport of PAA, 6‐APA and Pen‐G, more serious concentration polarization of Pen‐G occurred and the separation ratio of PAA to 6‐APA decreased.
Transport and separation of cobalt, nickel and copper ions with alamine liquid membranes
Authors: Marchese José , Campderrós Mercedes , Acosta Adolfo
Published: May 2005

The transfer and separation of Co(II), Ni(II) and Cu(II) ions across a flat‐sheet supported liquid membrane containing Alamine 336 as the mobile carrier dissolved in kerosene solvent has been investigated. Both the Alamine composition in the organic solution and the hydrochloric acid concentration in the feed solution have a marked effect on Co(II) and Cu(II) transport. A maximum flow of these ions at 50% of Alamine in the diluent was obtained. Ni(II) ion was not transported in the whole range of experimental conditions studied and good separation from Co(II) and Cu(II) could thus be performed. With decreasing hydrochloric acid concentration in the feed solution the separation factor of Cu(II) from Co(II) increases thus decreasing the Cu(II) recuperation factor.
The effect of cobalt on the activation of fused iron catalyst for ammonia synthesis
Authors: Kaleńczuk Ryszard J.
Published: May 2005

BET, scanning electron microscopy, X‐ray diffraction, Mössbauer spectroscopy, X‐ray fluorescence spectroscopy and McBain thermobalance were used to investigate the effect of cobalt on the reduction behavior and activity of used iron catalyst for ammonia synthesis. Activity tests were carried out under 10 MPa in the 350–450°C temperature rang. Studies were performed on the traditional multipromoted iron catalyst and on the series of catalysts prepared with addition of cobalt. Addition of cobalt promoted the iron catalyst for ammonia synthesis. The most active sample was that containing approx. 5.5% wt Co. Cobalt changed the reduction behavior of the catalyst. The rate of the surface change during reduction was higher for the case of the ‘cobalt catalyst’; however the rate of mass change was higher for a typical iron catalyst. The process of reduction was probably followed by the formation of an Fe3Co compound and by the surface faceting, with the exposure of an Fe(111) plane.
Gradient elution under hydrostatic equilibrium in liquid chromatography. Part 1
Authors: Said A. S.
Published: May 2005

The theory of gradient elution under hydrostatic equilibrium is developed for the case where only one reservoir and one mixing chamber are used and where both solvents have equal densities. Given the shapes of the two vessels, effluent concentration curve equations are deduced for different mixing chamber‐reservoir combinations. On the other hand, given the equation for the effluent concentration curve, the reservoir cross‐sectional area, as a function of height, can be deduced when the mixing chamber has a constant cross‐section. The varying cross‐section of the reservoir is accomplished by inserting thin discs of different areas on top of one another inside a regular vessel of constant cross‐section.

Except for complicated gradients, a given gradient can be accomplished using a reservoir with a cross‐sectional area which varies linearly with height. In the case of complex gradients, a reservoir having two or more linear segments becomes necessary. A numerical method is given for the calculation of the continuously varying reservoir cross‐section for the exact duplication of a given gradient.
Determination of triphenyltin hydroxide derivatives by capillary GC and tin‐selective FPD
Authors: Wright B. W. , Lee M. L. , Booth G. M.
Published: May 2005

A new method for the determination of triphenyltin hydroxide using capillary column gas chromatography with a tin‐selective flame photometric detector has been developed. Triphenyltin hydroxide and its potential metabolites are converted to methyl derivatives and separated on glass capillary columns coated with OV‐101. Derivatization of triphenyltin hydroxide, triphenyltin chloride, diphenyltin dichloride, phenyltin trichloride, and bis‐triphenyltin oxide is nearly quantitative with a minimum of redistribution products. The selectivity of the flame photometric detector is cearly demonstrated by the comparison of chromatographic profiles obtained from using both the flame photometric and flame ionization detectors.

The use of this chromatographic system in the analysis of triphenyltin hydroxide in a fortified water sample demonstrates the potential use of this system in organotin residue chemistry.
Effects of trapping temperature and film thickness in purge and trap with whole column cryotrapping on fused silica columns
Authors: Pankow J. F.
Published: May 2005

The effects of trapping temperature and column film thickness were investigated with respect to their ability to promote effective cryofocusing on fused silica capillary columns. The study was a further development of the purge and trap with whole column cryotrapping (P&T/WCC) method. The rates at which compounds could be thermally desorbed from a P&T unit and transferred to a column (with zero split) were first examined. A near quantitative transfer of the desorbable analytes was obtained with a 4 min, 180°C, 20 mL/min desorption. The compounds tested included naphthalene. Columns with film thicknesses from 0.12 to 3.0 μm were then investigated in P&T/WCC analyses with WCC temperatures ranging from −80 to 0°C. The trapping took place from a transfer line gas stream initially at 175°C. The volatilities of the compounds examined varied from that of 1,1‐dichloroethene to 1,1,2,2‐tetrachloroethane. A higher film thickness was found to ease the WCC temperature requirements. Within each column type, the warmest WCC temperatures which allowed good cryotrapping with no significant increases in peak width were: 0.25 μm, −70°C; 1.0 μm, −50°C; 3.0 μm, −20°C. In addition to being quantitative, the trapping provided good chromatography.
Capillary GC analysis of diesel fuels using simultaneous parallel triple detection
Authors: Williams P. T. , Bartle K. D. , Mills D. G. , Andrews G. E.
Published: May 2005

Diesel fuels from different parts of the UK have been analyzed for polycyclic aromatic hydrocarbons (PAH), nitrogen‐containing PAH, and sulfur‐containing PAH using capillary column GC with simultaneous parallel triple detection. The concentrations of polyaromatic compounds (PAC) were high and showed considerable variability amongst the fuels. The PAH are mainly naphthalene, fluorene, and phenanthrene and their alkylated homologs; the PANH are mainly carbazole and its methyl derivatives; the PASH are mainly dibenzothiophene and its methyl derivatives.
Preparation, evaluation, and comparison of wide bore (320 μm) and narrow bore (50 μm) cyanosilicone‐coated capillary columns for gas chromatography
Authors: Aerts A. , Rijks J. , Bemgard A. , Blomberg L.
Published: May 2005

The preparation of wide bore (320 μm) and narrow bore (50 μm) fused silica capillary columns is described for immobilized cyanopropyl substituted silicones containing 60 and 88% substitution. The effect of high temperature deactivation with cyanopropylcyclosiloxanes was studied with a special test mixture. Curing was achieved with dicumyl peroxide or azo‐tert‐butane.

The columns were evaluated and compared in terms of efficiency, activity, polarity, and temperature stability. Different coating methods were compared for the narrow bore columns. The activity of the 60% cyanopropyl columns that had been immobilized with dicumyl peroxide was significantly larger than for azo‐tert‐butane immobilized columns. The polarity of polar columns appeared to depend greatly on column temperature and is completely different for wide and narrow bore columns.
Further applications for capillary gas chromatography in routine quantitative toxicological analyses
Authors: Phillips A. Maury , Logan Barry K. , Stafford David T.
Published: May 2005

The use of capillary column gas chromatography for drug screening in forensic toxicology has become increasingly widespread. Screening procedures however are often lengthy and unsuitable for rapid confirmatory or quantitative applications. In order to develop a practical scheme for confirmatory/quantitative analysis, we have optimized a series of temperature profiles to allow the rapid quantitative determination of a wide range of acid/neutral and basic drugs in extracts from post mortem fluids and tissue. The appropriate profile is selected based on the retention index on a standard crosslinked methyl silicone column used to screen extracts. The use of a 5% phenyl methyl silicone phase allows complementary identification, and allows the separation of some pairs of compounds with identical retention indices in the screning procedure.
Optimization and application of the large volume on‐column introduction (LOCI) technique for capillary GC with preliminary on‐line capillary solvent distillation/concentration
Authors: Hiller Joseph F. , McCabe Terry , Morabito Paul L.
Published: May 2005

This report describes an on‐line capillary GC injection system which enables on‐column injection of a hundred or more microliters, and yields separations comparable with those obtained from on‐column injection of 1–2 microliters of solutions a hundred times more concentrated. Precision, carry‐over, linearity, and discrimination are comparable with those of classical sample‐introduction techniques. A selection of polar and high boiling compounds has been examined, and excellent peak shapes obtained for hundreds of injections. Initial results indicate that maintenance and long‐term reproducibility will also be comparable with those of classical techniques.

The instrument utilizes a version of the large volume on‐column injector with solvent diversion described in an earlier communication, with the addition of a method for independent heating of the retention gap. This modification reduces the effects of activity in the retention gap and improves the capability of the technology to handle complex mixtures. It also increases reliability and system lifetime, fits readily into most GC ovens, is easily automated, and should be compatible with all capillary GC detectors.
Confirmation of anabolic hormone residues in bovine blood by micro‐HPLC–ion spray–tandem mass spectrometry
Authors: Draisci Rosa , Giannetti Luigi , Lucentini Luca , Palleschi Luca , Purifacto Ivana , Moretti Gabriella
Published: May 2005

Sensitive, specific analytical methods for the determination of an‐abolics in biological matrices are essential to control the illegal use of these substances in food‐producing animals. Programs of residue control are performed annually in Italy for the determination of endogenous sex hormones (17β‐estradiol, progesterone, testoster‐one) for which maximum physiological levels have been established. At present the methods used in the Italian programs to determine natural hormones in bovine blood are based on the sensitive radio‐immunoassay (RIA), due to relatively low levels of these substances in plasma/serum. In this study, we report a new method based on tandem mass spectrometry with on‐line micro‐high performance liquid chromatography (micro‐HPLC‐MS‐MS) using an atmos‐pheric pressure ionization (API) source and an ion spray (IS) interface for the specific direct detection of natural (progesterone and testosterone), and synthetic (17β19‐nortestosterone and me‐droxyprogesterone) hormone residues in bovine serum. 17‐Methyl‐testosterone was used as the internal standard. Analytes were extracted with acetate buffer, purified on C18 Solid Phase Extrac‐tion (SPE) cartridge and separated on a reverse phase C18 micro‐HPLC column (300 mm × 1 mm, 5 μm), using acetonitrile‐water, 80:20 (v/v) containing 2mM ammonium acetate as the mobile phase, at a flow rate of 10 μl/min. When anabolic hormones were ionized in the IS interface operating in the positive ion mode, only the protonated molecules, [M+H]+, were generated, without evidence of any fragmentation. These served as precursor ions for collision induced dissociation (CID) and Diagnostic daughter ions for each analyte were identified in order to carry out analysis by micro‐HPLC‐MS‐MS in the selected reaction monitoring (SRM) mode. For the analytes in question, the response of the mass detector was related linearly to the quantity of each analyte injected between 10 and 300 pg, in the SRM mode. The limit of detection, based on a 3:1 signal‐to‐noise ratio, is 6–7 pg for the hormones. Recoveries were higher than 83% for 17β‐19‐nortestosterone, testosterone, and 17‐methyltestosterone, and 72% for the medroxyprogesterone, and progesterone. The micro‐HPLC‐MS‐MS method for the determi‐nation of anabolic hormones in bovine blood requires no sample derivatization, minimal sample preparation, and provides a sensi‐tive, selective, rapid alternative to the existing purification, separa‐tion, and detection techniques. At present this very sensitive method is being successfully applied to measure bovine serum concentra‐tions of natural hormones, such as testosterone and progesterone, in order to then confirm any illegal administration of these sub‐stances.
Hypoxic injury to oligodendrocytes: Reversible inhibition of ATP‐dependent transport of ceramide from the endoplasmic reticulum to the golgi
Authors: Kendler A. , Dawson G.
Published: May 2005

Previous studies have shown that gradual progressive hypoxia specifically inhibits the synthesis of the major myelin lipid galactosylceramide (GalCer) in cultured neonatal rat Oligodendrocytes (OLG) (Kendler and Dawson, J Biol Chem 265:12259–12266, 1990). The inhibition of de novo synthesized GalCer (measured by [3H]palmitate incorporation) was accompanied by an increase in the [3H]labeled pool of nonhydroxy fatty acid ceramide, the precursor of GalCer. The decreased galactosylation of NFACer was not due to an inhibition of UDP‐Gal:ceramide:galactosyltransferase activity or to a depletion in available UDP‐Gal. Analysis of subcellular fractionations of OLG membranes on Percoll gradients indicated that NFA ceramide was accumulating in the endoplasmic reticulum (ER) during hypoxia, suggesting that the transport of NFACer from its site of synthesis (ER) to its site of galactosylation, presumably the Golgi, was blocked by hypoxia. This accumulation of ceramide was replicated by lowering ATP levels to 80–90% of control by treating OLG with 12 nM oligomycin, and was reversed by reoxygenation of. the cells. Conversion of [3H] palmitate‐labeled NFACer to GalCer in semi‐intact OLG required both exogenous UDP‐Gal 1 and ATP, further suggesting that the transport of NFACer from the ER to its site of synthesis (cis‐ Golgi) is an energy‐dependent step that is highly susceptible to relatively minor ATP depletion associated with early hypoxic injury. Our results further suggest that ceramide appears to be a good marker for ER eland GalCer is a good marker for the cis‐Golgi.
Synergistic effects of nerve growth factor and phorbol 12‐myristate 13‐acetate on rapid motility and process formation in PC12 cells: The role of laminin
Authors: Glowacka D. , Ginty D. D. , Wagner J. A.
Published: May 2005

A126‐1B2 cells, a PKA (cAMP‐dependent protein kinase)‐deficient variant of PC12 cells, but not parental PC12 cells, form processes within 15–30 min of exposure to both nerve growth factor (NGF) and activators of protein kinase C when grown on tissue culture plastic (Glowacka and Wagner, J Neurosci Res 25: 453–462, 1990). Time‐lapse microscopy has demonstrated that these processes are formed by a novel mechanism, i.e., rapid movement of the cell body away from a point of attachment, which morphologically resembles a growth cone. These “fast” neurites are attached to the substratum at a number of points, which display membrane activity in the form of active ruffling and the extension of filopodia and membrane pleats. Thus, these processes are formed by a mechanism distinct from that used by PC12 and other neuronal cells to form processes in culture. Wild‐type PC12 cells also migrate and form fast neurites in response to a combination of NGF and phorbol 12‐myristate 13‐acetate (PMA), when they are grown in conditioned media or plates, suggesting that a secreted factor that can bind to the substratum is essential for the rapid formation of these neurites. Similarly, wild‐type PC12 cells grown on a laminincoated substratum also migrate and form “fast neurites” in response to a combination of NGF and PMA. This rapid migration is attenuated by an antiα1,β1‐integrin antisera, implicating a laminin‐integrin interaction; and it is inhibited by α‐lactalbumin, suggesting an involvement of a β1,4 galactosyltransferase in the response. The formation of fast neurites is not dependent on concurrent protein synthesis, but it is inhibited by lithium, cytochalasin D, and methylthioadenosine or pretreatment of cells with NGF. Thus PC12 cells grown on the appropriate substrate have the ability to migrate rapidly and thereby form neuron‐like processes within minutes of exposure to NGF and PMA. This morphological response to a combination of agents may provide an alternative means by which nerve cells form connections. Alternatively, it may reflect a mechanism that facilitates cellular migration during developmental processes.
Three‐dimensional reconstruction of bovine intradural spinal root myelin by electron microscope tomography
Authors: Sędzik J. , Öfverstedt L.‐G. , Skoglund U.
Published: May 2005

Electron microscope tomography was used to reconstruct three‐dimensionally the configuration of heavy metal staining in bovine intradural spinal root myelin. Samples were fixed with glutaraldehyde, exposed to osmium tetroxide, embedded, thin sectioned, and finally stained with uranyl‐acetate and lead citrate. Reconstructions up to 4.2 nm resolution showed a non‐uniform distribution of stain in the planes of individual cytoplasmfc appositions (major dense lines). In each reconstructed major dense line the stain was distributed in striated, well‐defined structures. Those structures appear to be nearly parallel between neighboring major dense lines. The distribution of stain in the Schmidt‐Lanterman cleft did not resemble the distribution of stain in the major dense line; however, weak striations were present. Evidence that the striated structures are not an artifact due to image calculation is discussed.
Substratum‐induced modulation of acetylcholinesterase activity in cultured dorsal root ganglion neurons
Authors: Gupta J. J. , Bigbee J. W.
Published: May 2005

Acetylcholinesterase (AChE) has been shown to be transiently expressed in the developing nervous system during periods of neuronal migration and axonal outgrowth. We are investigating the possible interaction of substratum with AChE activity in dorsal root ganglion neurons (DRGN) cultured on substrata with varying degrees of permissiveness for neurite outgrowth: (1) extracellular matrix substrata: reconstituted basal lamina Matrigel™ (MGEL), laminin (LAM) and type I collagen (COL), and (2) organotypic substrata: unfixed, frozen sections of sciatic nerve (SN) and spinal cord (SC). In group 1, histochemical staining for AChE in DRGN was lowest on MGEL where outgrowth was most vigorous, intermediate on LAM, and highest on COL where neurite outgrowth was reduced by 55 % compared to Matrigel™ and highly fasciculated. A similar trend was seen when the cultures were assayed biochemically, 2.84 ± 0.14 nmoles ACh hydrolyzed/ganglion/ hr (MGEL), 4.42 ± 0.19 (LAM), 5.79 ± 0.37 (COL). In group 2, SN supported an expansive outgrowth with lower AChE activity than in DRGN grown on SC where outgrowth was minimal. These studies show that the levels of AChE activity can be modulated by substratum, perhaps in proportion to the permissiveness of the substratum to neuritic outgrowth. These results are discussed in relation to possible non‐cholinergic roles of AChE.
Nerve growth factor and choline acetyltransferase activity levels in the rat brain following experimental impairment of cerebral glucose and energy metabolism
Authors: Hellweg R. , Nitsch R. , Hock C. , Jaksch M. , Hoyer S.
Published: May 2005

Intracerebroventricular (ICV) injection of streptozotocin (STZ) has been reported to impair cerebral glucose utilization and energy metabolism (Nitsch and Hoyer: Neurosci Lett, 128:199–202, 1991) and also to prejudice passive avoidance learning in adult rats (Mayer et al.: Brain Res 532:95–100, 1990). It is well established that the forebrain cholinergie whose integrity is essential for learning and memory functions, depends on the target‐derived retrograde messenger nerve growth factor (NGF). Therefore, we measured NGF and choline acetyltransferasc (ChAT) activity levels in the forebrain cholinergic system in adult rats that had received a single injection of either STZ or artificial cerebrospinal fluid into the left ventricle 1 or 3 weeks prior to sacrifice. One week after ICV STZ treatment, NGF content was significantly decreased (−32%) in the septal region, where NGF‐responsive cell bodies are located and NGF exerts its neurotrophic action after retrograde transport from NGF‐producing targets. In contrast, NGF levels in the cortex and hippocampus, which are target regions for the basal forebrain cholinergic neurons, and in the brainstem and cerebellum were increased ( + 12% to +47%) within 3 weeks after ICV STZ treatment. The alterations in NGF levels were not related to changes in ChAT activity that decreased in the hippocampus by only 15%. This might be due to maskling effects exerted by compensatory NGF‐mediated stimulation of ChAT activity in remaining functional neurons. It is suggested that impaired behavior which fnas been observed after STZ‐induced impairment of cerebral glucose and energy metabolism may be at least partially related to a diminished capacity of cental NGF‐responsive neurons to bind and/or transport NGF. Damage of the cerebral glucose and energy metabolism by ICV treatment with STZ may therefore provide an appropriate animal model for the study of the early metabolic events in brain abnormalities associated with cognitive impairments.
cDNA cloning and chromosome assignment of the gene for human brain 14–3–3 protein η chain
Authors: Ichimura‐Ohshima Y. , Morii K. , Ichimura T. , Araki K. , Takahashi Y. , Isobe T. , Minoshima S. , Fukuyama R. , Shimizu N. , Kuwano R.
Published: May 2005

We present the nucleotide sequence of a cDNA clone of mRNA encoding human 14‐3‐3 protein, a protein kinase‐dependent activator of tyrosine and tryp‐tophan hydroxylases and an endogenous inhibitor of protein kinase C. The 1,730‐nucleotide sequence of the cloned cDNA contains 191 bp of a 5′‐noncoding region, the complete 738 bp of coding region, and 801 bp of a 3′‐noncoding region containing three canonical polyadenylation signals. The 14‐3‐3 protein η chain cDNA encoded a polypeptide of 246 amino acids with a predicted molecular weight 28,196. The predicted amino acid sequence of human 14‐3‐3 protein η was highly homologous to that of previously reported bovine and rat 14‐3‐3 proteins with only two amino acid differences. The sequence carries structural features as putative regions responsible for activation of tyrosine and tryptophan hydroxylases and for inhibition of Ca2+/phospholipid‐dependent protein kinase C. Northern blot analysis demonstrated widespread expression of the 14‐3‐3 protein η chain in cultured cell lines derived from various human tumors. These findings suggest the conservative functions of the 14‐3‐3 protein among species. Spot blot hybridization analysis with flow‐sorted chromosomes it showed that the human 14‐3‐3 protein η chain gene is assigned to chromosome 22.
An immortalized cell line expresses properties of activated microglial cells
Authors: Bocchini V. , Mazzolla R. , Barluzzi R. , Blasi E. , Sick P. , Kettenmann H.
Published: May 2005

Murine cultured microglial cells were immortalized after infection with a v‐raf/v‐myc recombinant retro‐virus. This immortalized cell line (BV‐2) shares properties with body macrophages with respect to the antigen profile, their phagocytic capacity and antimicrobial activity. BV‐2 cells are not constitu‐tively able to kill tumor cells in vitro, but acquire antitumor activity following an increase in [Ca++]i. BV‐2 cells, like microglial cells, are however, distinct from peripheral macrophages by their expression of inwardly rectifying K+ cannels in concert with a Jack in outwardly rectifying K+ channels and the formation of spineous processes. The BV‐2 cell line thus represents a suitable model for in vitro studies of activated microglial cells.
Isolation and characterization of neonatal schwann cells from cryopreserved rat sciatic nerves
Authors: Mason P. W. , Attema B. L. , DeVries G. H.
Published: May 2005

Much of our knowledge about the development and maintenance of the peripheral nervous system has been learned through studying the interaction of neurons, or their isolated membranes, with Schwann cells (SC), in tissue culture. Numerous approaches have been employed to obtain an adequate quantity of SC, but all have been limited by either the uncertainty of obtaining a sufficient amount of starting material, the time and expertise required to isolate the SC, or by the limited number of SC that can be generated. We have developed a procedure to isolate SC from cryopreserved sciatic nerves. This procedure allows for sciatic nerves to be pooled until adequate numbers of nerves are obtained, yet still produces cells that retain the functional abilities of SC isolated from fresh nerves. Sciatic nerves were isolated from 2 day old rat pups, placed in either DME media and used fresh or placed in a freezing solution containing DME media (25%), DMSO (25%), fetal calf serum (50%), frozen at −70°C and stored in liquid nitrogen. The frozen nerves were rapidly thawed to 37°C and single cells were prepared from both fresh and frozen nerves using enzymatic and mechanical disruption as previously described (Brockes et al., Brain Res 165:105–118, 1979). Comparable cell yields were obtained for SC isolated from both frozen and fresh nerves. Immunohistochemical staining of both fresh and frozen SC produced similar staining patterns with antibodies to GFAP, laminin, CNPase, S100, MBP, and Po protein. Addition of axolemmal enriched membrane fractions to both the frozen and fresh SC gave a similar dose response curve of 3H‐thymidine incorporation, with SC from frozen sciatic nerves responding even better than fresh sciatic nerves at higher doses (50 μg and 100 μg of protein/ml). As demonstrated by the cell yield, immunohistochemical staining and responses to axolemmal mitogens, this procedure produces SC from frozen sciatic nerves with similar characteristics to those isolated from fresh nerves. This procedure will allow the production and utilization of a large number of SC, which will be critical in further studies on the development and maintenance of the peripheral nervous system.