bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of polyacrylamide‐co‐acrylic acid on cellulose production by Acetobacter xylinum
Authors: Joseph Gerard , Rowe Gerald E , Margaritis Argyrios , Wan Wankei
Published: August 2003

Polyacrylamide‐co‐acrylic acid (PA) added to shake flask cultures of Acetobacter xylinum at concentrations up to 3 g dm−3 resulted in increased production of bacterial cellulose. For PA concentrations of 0–3 g dm−3, 7‐day cellulose production rose monotonically from 2.7 ± 0.8 to 6.5 ± 0.5 g dm−3 at a shaker speed of 175 rpm, and from 1.7 ± 0.01 to 3.7 ± 0.5 g dm−3 at shaker speed of 375 rpm. Addition of PA also changed the morphology of the biomass from amorphous/stringy forms to spheroidal particles with diameters ≤2 mm. Similarly, bioreactor cultures grown in the absence of PA formed long fibrous masses which deposited on the internals, while those grown in the presence of 1–2 g dm−3 PA formed small discrete particles with diameters ≤0.1 mm. Tests performed with 1 and 2 g dm−3 PA, and stirrer speeds from 500 to 900 rpm, appeared to give the highest cellulose concentration of 5.3 ± 0.7 g dm−3 in 64–68.5 h in the presence of 2 g dm−3 PA at 700 rpm, although this value was statistically indistinguishable from that obtained at 1 g dm−3 PA and 900 rpm. A qualitative model is proposed to describe the mechanisms by which PA affects biomass morphology, resulting in its advantageous formation as small, dispersed, spheroidal pellets. Quantitative analysis of the results gave inverse correlations between both the fraction of fructose carbon going to cellulose synthesis and the specific fructose consumption rate, and the maximum cellulose concentration and the fraction of fructose carbon going to by‐product formation. Since cellulose yield was almost universally improved by higher polyacrylamide concentration, it appears likely that increased viscosity reduces fructose uptake rate by limiting mass transfer. Copyright © 2003 Society of Chemical Industry
Hydrodynamic considerations on optimal design of a three‐phase airlift bioreactor with high solids loading
Authors: Klein Jaroslav , Vicente António A , Teixeira José A
Published: August 2003

The hydrodynamic study of a three‐phase airlift (TPAL) bioreactor with an enlarged gas–liquid dual separator was carried out. Different lengths and diameters of the draft tube were tested to show how the design of the separator zone affects the hydrodynamic performance of the TPAL reactor. Ca‐alginate beads with entrapped yeast biomass at different loadings (0, 7, 14 and 21% v/v) were used in order to mimic the solid phase of conventional high cell density systems, such as those with cells immobilized on carriers or flocculating cells. Important information on multiphase flow and distribution of gas and solid phases in the internal‐loop airlift reactor (ALR) with high solids loading was obtained, which can be used for suggesting optimal hydrodynamic conditions in a TPAL bioreactor with high solids loading. It is finally suggested that the ALR with a dual separator and a downcomer to riser cross‐sectional area ratio (AD/AR) ranging from 1.2 to 2.0 can be successfully applied to batch/continuous high cell density systems, where the uniform distribution of solid phase, its efficient separation of particles from the liquid phase, and an improved residence time of air bubbles inside the reactor are desirable. Copyright © 2003 Society of Chemical Industry
Bacterial biodegradation of phenol and 2,4‐dichlorophenol
Authors: Gallizia Ilaria , McClean Stephen , Banat Ibrahim M
Published: August 2003

Nine bacterial strains capable of utilising phenol and 2,4‐dichlorophenol (DCP) have been isolated from a mixed culture grown on substrates containing these compounds. One of these strains, a Micrococcus sp, was further investigated under aerobic conditions using phenol and DCP as sole carbon and energy sources at various pH values. Phenol degradation was enhanced under alkaline conditions, and up to 500 mg dm−3 phenol was mineralised within 50 h at pH 10. DCP was more recalcitrant; however up to 883 mg g−1 and 230 mg g−1 were degraded within 10 days, when using initial DCP concentrations of 100 and 200 mg dm−3, respectively. Biomass measurements showed cell growth, proving that both phenol and DCP are used as growth substrates for this isolate. Copyright © 2003 Society of Chemical Industry
Photoelectrocatalytic humic acid degradation kinetics and effect of pH, applied potential and inorganic ions
Authors: Selcuk Huseyin , Sene Jeosadaque J , Anderson Marc A
Published: August 2003

This study addresses the removal of humic acid (HA) dissolved in an aqueous medium by a photoelectrocatalytic process. UV254 removal and the degradation of color (Vis400) followed pseudo‐first order kinetics. Rate constants were 1.1 × 10−1 min−1, 8.3 × 10−2 min−1 and 2.49 × 10−2 min−1 (R2 > 0.97) for UV254 degradation and 1.7 × 10−1 min−1, 6.5 × 10−2 min−1 and 2.0 × 10−2 min−1 for color removal from 5 mg dm−3, 10 mg dm−3 and 25 mg dm−3 HA respectively. Following a 2 h irradiation time, 96% of the color, 98% of the humic acid and 85% of the total organic carbon (TOC) was removed from an initial 25 mg dm−3 HA solution in the photoanode cell. Photocatalytic removal on the same photoanode was also studied in order to compare the two methods of degradation. Results showed that the photoelectrocatalytic method was much more effective than the photocatalytic method especially at high pH values and with respect to UV254 removal. The effect of other important reaction variables, eg pH, external potential and electrolyte concentration, on the photoelectrocatalytic HA degradation was also studied. Copyright © 2003 Society of Chemical Industry
Synthesis of [18F]‐labeled adenosine analogues as potential PET imaging agents
Authors: Alauddin Mian M. , Fissekis John D. , Conti Peter S.
Published: August 2003

The syntheses of adenosine analogues, 2′‐deoxy‐2′‐[18F]fluoro‐9‐β‐D‐arabinofuranosyladenine ([18F]‐FAA) and 3′‐deoxy‐3′‐[18F]fluoro‐9‐β‐D‐xylofuranosyladenine ([18F]‐FXA) are reported. Adenosine (1) was converted to its methoxytrityl derivatives 2 and 3 as a mixture. After separation, these derivatives were converted to their respective triflates 4 and 5. Each triflate was reacted with tetrabutylammonium[18F]fluoride to produce 6b or 7b, which by acidic hydrolysis yielded compounds 8b and 9b. Crude preparations were purified by HPLC to obtain the desired pure products. The radiochemical yields were 10‐18% decay corrected (d. c.) for 8b and 30‐40% (d. c.) for 9b in 4 and 3 runs, respectively. Radiochemical purity was >99% and specific activity was >74 GBq/μmol at the end of synthesis (EOS). The synthesis time was 90‐95 min from the end of bombardment (EOB). Copyright © 2003 John Wiley & Sons, Ltd.
Efficient synthesis of [11C]befloxatone, a selective radioligand for the in vivo imaging of MAO‐A density using PET
Authors: Dollé F. , Bramoullé Y. , Hinnen F. , Demphel S. , George P. , Bottlaender M.
Published: August 2003

Carbon‐11 labelled befloxatone ((5R)‐5‐(methoxymethyl)‐3‐[4‐[(3R)‐4,4,4‐trifluoro‐3‐hydroxybutoxy]phenyl]‐2‐oxazolidinone) is a reversible and selective monoamine oxidase‐A (MAO‐A) inhibitor and appears to be a new potent PET tracer for the in vivo imaging of MAO‐A density. In this paper, the radiosynthesis of befloxatone was investigated and orientated towards the preparation of multi milliCuries of radiotracer. Typically, using no‐carrier‐added [11C]phosgene, 150–300 mCi (5.55–11.10 GBq) of [11C]befloxatone was obtained within 20 min of radiosynthesis (including HPLC purification) with specific radioactivities ranging from 500 to 2000 mCi/µmol (18.5–74.0 GBq/µmol). The high efficiency of these radiosyntheses allows for multi‐injection protocols and kinetic approaches for absolute quantification of the tracer. Copyright © 2003 John Wiley & Sons, Ltd.
Regioselective F‐18 radiolabeling of AM694, a CB1 cannabinoid receptor ligand
Authors: Willis Peter G. , Katoch‐Rouse Reeti , Horti Andrew G.
Published: August 2003

[18F]AM694, [1‐(5‐[18F]fluoropentyl)‐1H‐indol‐3‐yl]‐(2‐iodophenyl)methanone, 1b, a potential radiotracer for imaging of cerebral cannabinoid receptor (CB1), has been synthesized by no‐carrier‐added regioselective radiofluorination of the corresponding tosylate. [18F]AM694 was obtained in 20% radiochemical yield (non‐decay‐corrected) with a specific activity of 14 500 mCi/µmol, a radiochemical purity of > 99%, and a chemical purity of 95.5%. Copyright © 2003 John Wiley & Sons, Ltd.
3H‐labelled alkyl‐nucleotides, ‐nucleosides and ‐bases for the immunoanalytical quantification of DNA damage and repair
Authors: Drosdziok Wolfgang , Lutze Catrin , Krüger Kai , Glüsenkamp Karl‐Heinz , Rajewsky Manfred F.
Published: August 2003

Analysis of the formation and repair of structurally modified DNA is of particular interest in the study of carcinogenesis, cancer therapy and aging. The quantification of specific DNA lesions by sensitive immunoanalytical methods requires radiotracers with high specific activity. We describe the synthesis of 3H‐labelled adenine‐, cytosine‐, guanine‐ and thymine‐alkyl derivatives by nucleophilic N‐ and O‐alkylation using alkyl halides and diazoalkanes: 3‐alkyl‐[8‐3H]adenine (Alkyl = Me, Et, n‐Bu); O6‐alkyl‐deoxy[1′,2′‐3H]guanosine (Alkyl = Me, Et, i‐Pro, n‐Bu); O6‐ethyl‐deoxyguanosine‐5′‐triphosphate ([2‐3H‐Ethyl]; [8‐3H]); O6‐alkyl‐9‐hydroxyhexyl‐[8‐3H] guanine (Alkyl=Me, Et); 7‐ethyl‐[8,5′‐3H]guanosine‐3′,5′‐cyclic‐phosphate; O2‐andO4‐alkyl‐[methyl, 1′,2′‐3H]thymidine (Alkyl=Me, Et); the conversion of 3H‐labelled thymidine to the corresponding 5‐methylcytidine; the synthesis of three different 8‐oxo‐guanine tracers; and the generation of thymidine glycol (5,6‐dihydroxy‐5,6‐dihydro‐[methyl‐3H]thymidine) from thymidine. All radiotracers were sucessfully employed in competitive radioimmunoassays for the quantification of defined DNA alkylation products in DNA repair analyses. Copyright © 2003 John Wiley & Sons, Ltd.
Efficient in‐loop synthesis of high specific radioactivity [11C]carfentanil
Authors: Studenov Andrei R. , Jivan Salma , Buckley Kenneth R. , Adam Michael J.
Published: August 2003

The synthesis of the precursor for [11C]carfentanil and the precursor labelling with 11C have both been improved. The problem ‘bottleneck’ step in the carfentanil precursor synthesis, due to low chemical yield (14%) of intermediates nitrile into amide conversion, has been solved. Application of a H2O2/K2CO3/DMSO reaction method significantly increased the yield of this chemical transformation (up to 84%). A simple and straight‐forward synthesis of [11C]carfentanil was achieved by combining in‐loop methylation of the ammonia salt of the precursor by [11C]CH3I, using tetrabutylammonium hydroxide as a base, with a previously developed product purification procedure using a C2 extraction disc. A decay corrected yield with respect to [11C]CH3I of [11C]carfentanil was 64±12% (n=6) with the synthesis time of 21 min. The radiochemical purity was >98%. Comparatively high specific radioactivity of [11C]carfentanil [11.2±4.8 Ci/μmol (EOS, n=5)] was partially attributed to the use of [11C]methane target gas for production of carbon‐11 methyl iodide. Copyright © 2003 John Wiley & Sons, Ltd.
‘Mass defect’ tags for biomolecular mass spectrometry
Authors: Hall Michael P. , Ashrafi Siamak , Obegi Imad , Petesch Robert , Peterson Jeffrey N. , Schneider Luke V.
Published: August 2003

We present a new class of ‘mass defect’ tags with utility in biomolecular mass spectrometry. These tags, incorporating element(s) with atomic numbers between 17 (Cl) and 77 (Ir), have a substantially different nuclear binding energy (mass defect) from the elements common to biomolecules. This mass defect yields a readily resolvable mass difference between tagged and untagged species in high‐resolution mass spectrometers. We present the use of a subset of these tags in a new protein sequencing application. This sequencing technique has advantages over existing mass spectral protein identification methodologies: intact proteins are quickly sequenced and unambiguously identified using only an inexpensive, robust mass spectrometer. We discuss the potential broader utility of these tags for the sequencing of other biomolecules, differential display applications and combinatorial methods. Copyright © 2003 John Wiley & Sons, Ltd.
A strategy for liquid chromatography/tandem mass spectrometric assays of intracellular drugs: application to the validation of the triphosphorylated anabolite of antiretrovirals in peripheral blood mononuclear cells
Authors: Becher François , Pruvost Alain , Gale Jane , Couerbe Philippe , Goujard Cécile , Boutet Valerie , Ezan Eric , Grassi Jacques , Benech Henri
Published: August 2003

The pharmacokinetics of intracellular drugs have recently aroused new interest because monitoring a drug's behaviour near the site of action can enhance knowledge of its efficacy and toxicity. Liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) is particularly attractive for intracellular analytes. Very few papers deal precisely with special features encountered in intracellular drug assay or with how closely the assay matches the actual recommendations.

Particular problems are encountered mainly because the analytes are located intracellularly. This mainly concerns the handling of biological media, including provision of blank samples using Ficoll gradient separation, cell counts, optimisation of cell lysis, sample extraction, plotting standard curves using either fmol/106 cells or fmol/ml of extract or fmol/sample, the matrix effect as a function of the number of cells, stability before and during cell separation, as well as in storage conditions using clinical samples, biological matrix replacement and interference by endogenous compounds.

This paper describes a strategy for the full validation and routine use of an LC/MS/MS assay applied to the simultaneous intracellular determination of the triphosphorylated anabolites of didanosine (2′,3′‐dideoxyadenosine triphosphate or ddA‐TP) and stavudine (2′,3′‐didehydro‐3′‐deoxythymidine triphosphate or d4T‐TP), two nucleoside reverse transcriptase inhibitors of HIV, in human peripheral blood mononuclear cells (PBMCs), as a guide for further LC/MS/MS assay of intracellular drugs. Copyright © 2003 John Wiley & Sons, Ltd.
New strategy for the determination of gliadins in maize‐ or rice‐based foods matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry: fractionation of gliadins from maize or rice prolamins by acidic treatment
Authors: Hernando Alberto , Valdes Israel , Méndez Enrique
Published: August 2003

A procedure for determining small quantities of gliadins by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) in gluten‐free foods containing relatively large amounts of prolamin proteins from maize or rice is described. We report for the first time that gliadins, the ethanol‐soluble wheat prolamin fraction, can be quantitatively solubilized in 1.0 M acetic acid, while the corresponding ethanol‐soluble maize or rice prolamin fraction remains insoluble in acetic acid. We describe a methodology for the detection of gliadins in maize and rice foods based on a two‐step procedure of extraction (60% aqueous ethanol followed by 1 M acetic acid). Subsequent MALDI‐TOFMS analysis of the resulting acidic extract from these gluten‐free foods clearly confirms the presence of a typical mass pattern corresponding to gliadin components, ranging from 30 to 45 kDa. Depending on the percentages of maize or rice flours employed in the elaboration of these foods, the combined procedure enables levels of gliadins from 100 to 400 ppm to be detected. The efficiency of this combined procedure corroborates enzyme‐linked immunosorbent assay data for a large number of maize/rice gluten‐free foods by means of direct visualization of the characteristic gliadin mass pattern in maize or rice foods. Copyright © 2003 John Wiley & Sons, Ltd.
Separation of 11 protease and reverse transcriptase inhibitors by capillary zone electrophoresis
Authors: Gutleben Wolfgang , Scherer Karin , Tuan Nguyen Duc , Stoiber Heribert , Dierich Manfred P. , Zemann Andreas
Published: August 2003

Capillary zone electrophoresis is employed for the simultaneous screening of protease and reverse transcriptase inhibitors which are used as antiretroviral therapy drugs against the Human Immunodeficiency Virus. Because of the basic character of the analytes, the electrophoretic system makes use of an acidic buffer electrolyte. In order to establish a strong anodic electroosmotic flow, a cationic surfactant is added to the background electrolyte. This causes the cationic analytes to migrate against the electroosmotic stream (counter‐electroosmotic CE). The developed separation system permits a simultaneous separation of protease and reverse transcriptase inhibitors with good selectivity and sensitivity.
Quantitative determination of rutin, quercetin, and adenosine in Flos Carthami by capillary electrophoresis
Authors: Sun Yi , Guo Tao , Sui Yin , Li Famei
Published: August 2003

A capillary electrophoresis method was developed for the separation and determination of adenosine, rutin, and quercetin in Flos Carthami. The CE separation was achieved using 50 mmol L–1 sodium tetraborate solution (pH 9.7) containing 18% methanol as the running buffer, with an applied voltage of 24 kV and detection at 210 nm. The contents of these constituents in an ethanol‐water extract of Flos Carthami could be easily determined within 45 min. The RSDs of the contents of these constituents were within 5.2% (n = 5). The contents of adenosine, rutin, and quercetin were determined in Flos Carthami from ten sources. Differences in contents were observed between various sources, which may be attributed to the growth environment of the plant, the time of harvesting, the storage conditions, and the drying process. The current method may serve as a valuable tool for the quality control of Flos Carthami.
Capillary electrophoresis profiles of fucoidan and heparin fractions: significance of mobility dispersity for their characterization
Authors: Kim Moo Young , Varenne Anne , Daniel Régis , Gareil Pierre
Published: August 2003

Capillary electrophoresis was investigated for characterization of the natural anionic polysaccharide fucoidan from marine brown algae and its comparison with heparin under different pH, ionic strength, and counter‐ion conditions. Reproducible profiles of these polysaccharides were obtained in indirect UV detection mode by introducing sulfosalicylic acid or anisic acid as chromophores in background electrolytes. Theoretical evaluations of zone spreading originating from molecular diffusion, electromigration, and initial zone width have shown that these dispersive contributions remain negligible compared to the overall profile dispersion. Therefore, the conversion of the experimental electropherograms (absorbance vs. time plots) into absorbance vs. electrophoretic mobility curves enables a comparison of these polysaccharides in terms of electrophoretic mobility dispersity. Nevertheless, a linear correlation between mobility and chemical charge rate cannot be established for these highly sulfated polysaccharides, because their chemical charge rate is higher than the threshold value for which counter‐ion condensation occurs.
A portable multi‐dimensional gas chromatographic system for field applications
Authors: Wahl Jon H. , Riechers Douglas M. , Vucelick Mark E. , Wright Bob W.
Published: August 2003

We have constructed and tested a multi‐dimensional gas chromatographic system that can be utilized for field portable applications. The chromatographic system is capable of one‐dimensional separations and multi‐dimensional gas chromatographic (MDGC) separations in a single compact package. Three different general multi‐dimensional separation approaches are possible: column switching; traditional heart‐cutting; and comprehensive analyses. The MDGC system utilizes a simple 10‐port valving approach to accomplish these separations to a single point detector. Because of this valving scheme no hardware change is required to switch between the heart‐cut and the comprehensive separation modes, only a software methodology change is required. An additional advantage of this valving approach is that 100% of the first‐dimensional effluent is sampled to the second dimension for separation. The system is capable of rapid column heating (room temperature to 250°C in approximately 10 s) and rapid column cooling (250°C to room temperature within approximately 30 s). Preliminary results for heart‐cut and comprehensive separations that target five compounds against high concentration levels of complex background are illustrated.
Performance of three chemically‐ modified silica materials for solid phase extraction of polar compounds from aqueous solutions
Authors: Pizzolato Tânia Mara , Foschiera José Luis , Benvenutti Edilson , Gomes Fabiana , Geller Ana Maria , Lopes Adriana , do Carmo Ruaro Peralba Maria , dos Santos João H. Z.
Published: August 2003

Silica gel (320 m2g–1, 10 nm) was chemically modified with 3‐chloropropyltrimethoxysilane or 3‐aminopropyltrimethoxysilane, followed by reaction with aniline, 3‐phenylchloropropylamine, or benzylamine. The resulting silicas were characterized by elemental analysis and spectroscopic techniques, namely diffuse reflectance spectroscopy (DRS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and 29Si variable amplitude cross‐polarization magic‐angle spin nuclear magnetic resonance (VACP‐MAS‐NMR). The resulting solids were shown to be stable in aqueous and non‐aqueous media and were tested as sorbents for pre‐concentration of derivatized phenolic compounds (acetyl derivatives of: phenol, o‐cresol, m‐cresol, p‐cresol, 2‐ethylphenol, 3‐ethylphenol, and 4‐ethylphenol) and some organochloride pesticides (endrin, pentachlorobenzene, heptachloro epoxide, hexachlorobenzene, and lindane) in aqueous media. Extractionexperiments were undertaken using a precleaned cartridge (10 cm×10 mm ID) packed with modified silica gel and with commercial C‐18 in order to evaluate the influence of the nature of the functional group onretention of the compounds under study. Results showed that silica modified with aniline gave the highest retention for the studied acetylated phenolic compounds. Silica modified with 3‐phenylchloropropyl groups exhibited the highest retention for hexachlorobenzene and aldrin, while that modified with benzylamine showed the highest retentionfor eldrin, pentachlorobenzene, and heptachloro epoxide. Lindane was not retained by any of the tested materials.
Non‐specific retention characteristics of dissolved β‐cyclodextrin derivatives in open tubular column gas chromatography
Authors: Kiridena Waruna , Poole Colin F. , Nawas Mohamed I. , Koziol Wladyslaw W.
Published: August 2003

The solvation parameter model is used to identify contributions from intermolecular interactions responsible for non‐specific retention in gas chromatography for three dissolved β‐cyclodextrin derivatives in a poly(cyanopropylphenyldimethylsiloxane) stationary phase. The cyclodextrins are permethylated β‐cyclodextrin (Cyclodex‐B), heptakis(2,3‐di‐O‐methyl‐6‐O‐t‐butyldimethylsilyl)‐β‐cyclodextrin (CycloSil‐B) and heptakis(2,3‐di‐O‐acetoxy‐6‐O‐t‐butyldimethylsilyl)‐β‐cyclodextrin (Rt‐βDEXsa). Taking DB‐1701 as a reference phase for the poly(cyanopropylphenyldimethylsiloxane) solvent, it is shown that the dominant interactions for the cyclodextrin derivatives are associated with their hydrogen‐bond basicity and capacity for dipole‐type interactions. None of the cyclodextrin derivatives are hydrogen‐bond acids and all are weakly electron lone pair repulsive. The cohesive properties of the dissolved phases are similar to those of the solvent, except for Rt‐βDEXsa, which is significantly more cohesive. Also, Rt‐βDEXsa shows significant inclusion complexation for the compounds used to determine the system constants of the solvation parameter model resulting in poor statistical models, suitable only for qualitative interpretation. The Cyclodex‐B and CycloSil‐B columns are compared to a database of 23 open‐tubular column stationary phases possessing similar selectivity to each other but different selectivity for non‐specific interactions to the other stationary phase types.
Evaluation of denaturing conditions in analysis of DNA variants applied to multi‐capillary electrophoresis instruments
Authors: Bjørheim Jens , Minarik Marek , Gaudernack Gustav , Ekstrøm Per Olaf
Published: August 2003

Denaturant slab gel techniques (DGGE and variants thereof) and denaturing CE (DCE) have been used for the analysis of mutations and single nucleotide polymorphisms by several research groups. Recently, DCE applied to commercially available capillary electrophoresis instruments has been demonstrated to be sensitive, specific, and robust for mutation and SNP analysis. However, instruments currently available on the market are not designed for DCE in their present forms. In both single and multi‐capillary instruments inaccurate temperature control units lead to irreproducible denaturing conditions, both between runs and from capillary to capillary within an electrophoresis run. We have previously suggested that cycling a temperature gradient several times around a theoretically defined optimum for a given DNA fragment results in more reproducible and controllable denaturing conditions compared to a constant denaturant or single sweep temperature gradient. In this paper, we demonstrate that with the temperature differences observed, the common technique of applying a temperature gradient is not sufficient for optimal separation conditions in all capillaries. Furthermore, we demonstrate that cycling of the temperature around a fragment's theoretically calculated melting temperature during electrophoresis leads to reproducible results in all capillaries. These results clearly show the potential of standard commercial capillary instruments in automated cycling temperature CE applications.
Direct resolution of novel tetrahedral metal clusters on a cellulose tris‐(3,5‐dimethylphenylcarbamate) chiral stationary phase by high‐performance liquid chromatography
Authors: Zhu Xinyi , Cai Yingchun , Zhang Weiqiang , Chen Liren , Li Yongmin
Published: August 2003

Direct optical resolution of five novel tetrahedral heterometal cluster enantiomers has been achieved for the first time on a cellulose tris‐(3,5‐dimethylphenylcarbamate) chiral stationary phase, using hexane as the mobile phase with various alcohols as modifiers. UV detection was carried out at 254 nm. The influence of the mobile phase composition on enantioselectivity is discussed and optimum resolution has been achieved. The effect of structural variation of the solutes on their enantioseparation has also been investigated.
Determination of pharmaceutical process impurities by solid phase microextraction gas chromatography
Authors: Frost Richard P. , Hussain Mumtaz S. , Raghani Anil R.
Published: August 2003

A methodology for automated headspace solid‐phase microextraction for the trace analysis of pharmaceutical process‐related toxic impurities such as benzyl chloride, triethyl amine, chloroethyl methyl ether, N‐methylmorpholine, and N‐methylpyrrolidinone by gas chromatography and flame ionization detection is reported. Carboxen/polysiloxane/divinylbenzene fiber showed excellent sensitivity towards these analytes compared to direct injection and the highest sensitivity among the commercial SPME fibers evaluated in this study. However, a profound effect of competition for the available adsorption sites was observed on the Carboxen/PDMS/DVB fiber. The effects of extraction parameters such as extraction time, temperature, agitation rate, and headspace volume were studied. The influence of the addition of inorganic salt on the analyte extraction efficiency was also investigated. The sensitivity of method extended to the sub‐ppm level with acceptable precision and accuracy. The linearity of the method covered one order of magnitude. The narrower linear dynamic range is attributed largely to the limited number of adsorption sites on the Carboxen/PDMS/DVB fiber.
Large volume injection GC‐MS in electron capture negative ion mode utilizing isotopic dilution for the determination of polybrominated diphenyl ethers in air
Authors: Björklund Jonas , Tollbäck Petter , Östman Conny
Published: August 2003

A large volume injection GC‐MS method for the determination of polybrominated diphenyl ethers (PBDEs) is presented. A loop‐type injection system with an early solvent vapor exit has been constructed and evaluated. With this system sample volumes up to 500 μL could be injected with high reproducibility and low carry‐over. The peak distortion problem associated with this kind of injection system is discussed in detail and solutions are suggested. We also introduce 13C‐labeled BDE‐209 as internal surrogate standard for the determination of high molecular weight PBDEs in low‐resolution mass spectrometry electron capture negative ionization mode. The complete method has been applied to air samples from an electronic waste dismantling facility, collected with personal exposure measurement equipment. Nine BDE congeners have been identified and quantified.
The relevance of MCDM for financial decisions
Authors: Hallerbach Winfried G. , Spronk Jaap
Published: August 2003

For people working in finance, either in academia or in practice or in both, the combination of ‘finance’ and ‘multiple criteria’ is not obvious. However, we believe that many of the tools developed in the field of MCDM can contribute both to the quality of the financial economic decision making process and to the quality of the resulting decisions. In this paper we answer the question why financial decision problems should be considered as multiple criteria decision problems and should be treated accordingly. Copyright © 2003 John Wiley & Sons, Ltd.
Evolving economy bank asset‐liability and risk management under uncertainty with hierarchical objectives and nonlinear pricing
Authors: Dash Gordon H. , Kajiji Nina
Published: August 2003

Quantitative modelling of the asset‐liability management (ALM) problem faced by banking institutions is reexamined in this paper. The model presented here joins stochastic programming with non‐linear goal programming (SNGP). A bank optimization model with multiple objectives, multiple non‐linear economic relationships and a complex options hedge is proposed as an extension to the contemporary model structure now used by most financial institutions. The model structure is particularly well suited to solve the ALM decision problem in evolving economies where shareholder value maximization is often stated across a multiple goal hierarchy. The result of solving the SNGP provided significant evidence that the method is viable for efficient bank management under quasi‐planned economics. Stating the non‐linear demand and supply relationships within the two‐stage representation of the stochastic decision environment proved to be an effective method for resolving complex pricing policy issues. Finally, the SNGP model extends prior ALM models by simultaneously hedging interest rate risk under uncertainty through the incorporation of a complex chooser option. The complex chooser option, a hedge with a known pay‐off, was chosen to assist an inexperienced management team with an effective risk‐abatement tool. Copyright © 2003 John Wiley & Sons, Ltd.
A multi‐criterion approach for selecting attractive portfolio
Authors: Bouri A. , Martel J. M. , Chabchoub H.
Published: August 2003

According to the conventional theory of finance, maximizing return with minimum risk should be a hallmark of every successful investor. However, contrary to the theoretical expectations of the conventional theory, the tests achieved on most financial markets have revealed the existence of other variables. Morever, behavioural aspects, like the investor's attitude to solvency and liquidity, are not taken into consideration. Then the problem of selecting an attractive portfolio is a multi‐criteria issue which should be tackled by using the appropriate techniques. A Multicriterion approach is proposed and applied to the Tunisian Stock Market to select an attractive portfolio. Copyright © 2003 John Wiley & Sons, Ltd.
On the use of a multi‐criteria hierarchical discrimination approach for country risk assessment
Authors: Doumpos M. , Zopounidis C.
Published: August 2003

Country risk is an issue with multidimensional implications in economic and social development at the national, regional and global levels. The assessment of country risk is often realized as a classification problem, involving the assignment of the countries into predefined groups according to their economic prospects. Within this framework, this study employs the MHDIS multi‐criteria decision aid method (Multi‐group Hierarchical DIScrimination) for developing country risk assessment models. The data used in the analysis involve a set of 161 countries obtained from the World Bank. An extensive comparison is also performed with other well‐known parametric and non‐parametric classification methods. Copyright © 2003 John Wiley & Sons, Ltd.
Identification of biologic markers of the premature rupture of fetal membranes: Proteomic approach
Authors: Vuadens Françoise , Benay Corinne , Crettaz David , Gallot Denis , Sapin Vincent , Schneider Philippe , Bienvenut Willy‐Vincent , Lémery Didier , Quadroni Manfredo , Dastugue Bernard , Tissot Jean‐Daniel
Published: August 2003

In obstetrics, premature rupture of the membranes (PROM) is a frequent observation which is responsible for many premature deliveries. PROM is also associated with an increased risk of fetal and maternal infections. Early diagnosis is mandatory in order to decrease such complications. Despite that current biological tests allowing the diagnosis of PROM are both sensitive and specific, contamination of the samples by maternal blood can induce false positive results. Therefore, in order to identify new potential markers of PROM (present only in amniotic blood, and absent in maternal blood), proteomic studies were undertaken on samples collected from six women at terms (pairs of maternal plasma and amniotic fluid) as well as on four samples of amniotic fluid collected from other women at the 17th week of gestation. All samples (N = 16) were analyzed by two‐dimensional (2‐D) high‐resolution electrophoresis, followed by sensitive silver staining. The gel images were studied using bioinformatic tools. Analyses were focused on regions corresponding to pI between 4.5 and 7 and to molecular masses between 20 and 50 kDa. In this area, 646 ± 113 spots were detected, and 27 spots appeared to be present on the gels of amniotic fluid, but were absent on those of maternal plasma. Nine out of these 27 spots were also observed on the gels of the four samples of amniotic fluids collected at the 17th week of pregnancy. Five of these 9 spots were unambiguously detected on preparative 2‐D gels stained by Coomassie blue, and were identified by mass spectrometry analyses. Three spots corresponded to fragments of plasma proteins, and 2 appeared to be fragments of proteins not known to be present in plasma. These 2 proteins were agrin (SWISS‐PROT: O00468) and perlecan (SWISS‐PROT: P98160). Our results show that proteomics is a valuable approach to identify new potential biological markers for future PROM diagnosis.
Proteomics application exercise of the Swiss Proteomics Society: Report of the SPS'02 session
Authors: Binz Pierre‐Alain , Abdi Fadi , Affolter Michael , Allard Laure , Barblan Jachen , Bhardwaj Sanjeev , Bienvenut Willy V. , Bulet Philippe , Burgess Jennifer , Carrette Odile , Corthals Garry , Delalande François , Diemer Hélène , Favreau Philippe , Giuliano Elia , Gueguen Yannick , Guillaume Elisabeth , Hahner Stephanie , Man Petr , Michalet Sophie , Neri Dario , Noukakis Dimitrios , Palagi Patricia , Paroutaud Pierre , Carvalho Pimenta Daniel , Quadroni Manfredo , Resemann Anja , Richert Sophie , Rybak Jascha , Sanchez Jean‐Charles , Scherl Alexander , Scheurer Simone , Schweiger Hufnagel Ulrike , Siethoff Christoph , Suckau Detlev , van Dorsselaer Alain , Wagner Redeker Winfried , Walter Nadia , Stöcklin Reto
Published: August 2003

After the success of the mass spectrometry (MS) round table that was held at the first Swiss Proteomics Society congress (SPS'01) in Geneva, the SPS has organized a proteomics application exercise and allocated a full session at the SPS'02 congress. The main objective was to encourage the exchange of expertise in protein identification, with a focus on the use of mass spectrometry, and to create a bridge between the users’ questions and the instrument providers’ solutions. Two samples were sent to fifteen interested labs, including academic groups and MS hardware providers. Participants were asked to identify and partially characterize the samples. They consisted of a complex mixture of peptide/proteins (sample A) and an almost pure recombinant peptide carrying post‐translational modifications (sample B). Sample A was an extract of snake venom from the species Bothrops jararaca. Sample B was a recombinant and modified peptide derived from the shrimp Penaeus vannamei penaeidin 3a. The eight labs that returned results reported the use of a wide range of MS instrumentation and techniques. They mentioned a variety of time and manpower allocations. The origin of sample A was generally identified together with a number of database protein entries. The difficulty of the sample identification lay in the incomplete knowledge of the Bothrops species genome sequence and is discussed. Sample B was generally and correctly identified as penaeidin. However, only one group reported the full primary structure. Interestingly, the approaches were again varied and are discussed in the text.
Detection of in situ labeled cell surface proteins by mass spectrometry: Application to the membrane subproteome of human mammary epithelial cells
Authors: Chen Wan‐Nan U. , Yu Li‐Rong , Strittmatter Eric F. , Thrall Brian D. , Camp David G. , Smith Richard D.
Published: August 2003

Characterization of the surface exposed membrane subproteome of human mammary epithelial cells (strain 184 A1L5) implemented lysine specific in situ labeling of the proteins using sulfosuccinimidyl‐6‐(biotinamido)hexanoate, followed by enrichment of the biotinylated, tryptically digested peptides, and then liquid chromatography‐tandem mass spectrometry analysis of the labeled peptides. Probing the membrane subproteome in this manner yielded unambiguous identification of proteins situated on the cell surface. The method reported can be adapted to include stable isotope labeling of proteins for quantitation of changes occurring on the cell surface in response to specific perturbations.
A panel of cerebrospinal fluid potential biomarkers for the diagnosis of Alzheimer's disease
Authors: Carrette Odile , Demalte Isabelle , Scherl Alexander , Yalkinoglu Oezkarn , Corthals Garry , Burkhard Pierre , Hochstrasser Denis F. , Sanchez Jean‐Charles
Published: August 2003

The diagnosis of Alzheimer's disease (AD), the most common form of dementia in the general population, usually relies upon the presence of typical clinical features and structural changes on brain magnetic resonance imaging. Over the last decade, a number of biological abnormalities have been reported in the cerebrospinal fluid (CSF) of AD patients, in particular altered levels of the tau protein and the 1‐42 fragment of the amyloid precursor protein. These, however, have not yet proved sensitive and specific enough to be included in the diagnostic criteria for AD, leaving plenty of room for the search of novel biomarkers. The present study describes the analysis of CSF polypeptides by a protein‐chip array technology called surface enhanced laser desorption/ionization‐time of flight‐mass spectrometry (SELDI‐TOF‐MS). Using this approach, we detected statistically significant quantitative differences (p < 0.05) regarding four overexpressed and one underexpressed polypeptides in the CSF of AD patients as compared to healthy controls. Four of them were further purified by strong anionic exchange chromatography (SAX) and identified by MS analysis as cystatin C, two β‐2‐microglobulin isoforms, an unknown 7.7 kDa polypeptide, and a 4.8 kDa VGF polypeptide. The combination of the five polypeptides for the diagnosis of AD allowed to classified six AD patients out of the nine included in this study and all the ten controls, which means in this small cohort that the specificity and sensitivity are 100% and 66%, respectively. This study, based on the protein‐chip array technology, demonstrates the presence in the CSF of novel potential biomarkers for AD, which may be used for the diagnosis and perhaps the assessment of the severity and progression of the disease.
Prefractionation techniques in proteome analysis
Authors: Righetti Pier Giorgio , Castagna Annalisa , Herbert Ben , Reymond Frederic , Rossier Joël S.
Published: August 2003

The present review deals with a number of prefractionation protocols in preparation for two‐dimensional map analysis, both in the fields of chromatography and in the field of electrophoresis. In the first case, Fountoulaki’s groups has reported just about any chromatographic procedure useful as a prefractionation step, including affinity, ion‐exchange, and reversed‐phase resins. As a result of the various enrichment steps, several hundred new species, previously undetected in unfractionated samples, could be revealed for the first time. Electrophoretic prefractionation protocols include all those electrokinetic methodologies which are performed in free solution, essentially all relying on isoelectric focusing steps. The devices here reviewed include multichamber apparatus, such as the multicompartment electrolyzer with Immobiline membranes, Off‐Gel electrophoresis in a multicup device and the Rotofor, an instrument also based on a multichamber system but exploiting the conventional technique of carrier‐ampholyte‐focusing. Other instruments of interest are the Octopus, a continuous‐flow device for isoelectric focusing in a upward flowing liquid curtain, and the Gradiflow, where different pI cuts are obtained by a multistep passage through two compartments buffered at different pH values. It is felt that this panoply of methods could offer a strong step forward in “mining below the tip of the iceberg” for detecting the “unseen proteome”.
OLAV: Towards high‐throughput tandem mass spectrometry data identification
Authors: Colinge Jacques , Masselot Alexandre , Giron Marc , Dessingy Thierry , Magnin Jérôme
Published: August 2003

Mass spectrometry combined with database searching has become the preferred method for identifying proteins in proteomics projects. Proteins are digested by one or several enzymes to obtain peptides, which are analyzed by mass spectrometry. We introduce a new family of scoring schemes, named OLAV, aimed at identifying peptides in a database from their tandem mass spectra. OLAV scoring schemes are based on signal detection theory, and exploit mass spectrometry information more extensively than previously existing schemes. We also introduce a new concept of structural matching that uses pattern detection methods to better separate true from false positives. We show the superiority of OLAV scoring schemes compared to MASCOT, a widely used identification program. We believe that this work introduces a new way of designing scoring schemes that are especially adapted to high‐throughput projects such as GeneProt large‐scale human plasma project, where it is impractical to check all identifications manually.
Preprocessing of tandem mass spectrometric data to support automatic protein identification
Authors: Gentzel Marc , Köcher Thomas , Ponnusamy Saravanan , Wilm Matthias
Published: August 2003

Liquid chromatography tandem mass spectrometry is a major tool for identifying proteins. The fragment spectra of peptides can be interpreted automatically in conjunction with a sequence database search. With the development of powerful automatic search engines, research now focuses on optimizing the result returned from database searches. We present a series of preprocessing steps for fragment spectra to increase the accuracy and specificity of automatic database searches. After processing, the correct amino acid sequences from the database can be related better to the fragment spectra. This increases the sensitivity and reliability of protein identifications, especially with very large genomic databanks, and can be important for the systematic characterization of post‐translational modifications.
Mass spectrometric proteome analysis for profiling temperature‐dependent changes of protein expression in wild‐typeCaenorhabditis elegans
Authors: Mádi András , Mikkat Stefan , Ringel Bruno , Ulbrich Markus , Thiesen Hans‐Jürgen , Glocker Michael O.
Published: August 2003

We investigated the effect of cultivation temperatures on the protein expression levels in the fourth larval stage of the postembryonic development of wild‐typeCaenorhabditis elegansby mass spectrometric proteome analysis. From the 64 protein spots that were investigated, 5 spots were found reproducibly differently expressed when proteome maps derived from animals kept at 15°C and at 25°C, respectively, were compared. Spots of heat shock proteins HSP 70 (CE18679 or CE09682) and HSP 16 (CE14249) were present only in gels from protein extracts when worms were grown at 15°C. Spots of two metabolic enzymes, the isocitrate dehydrogenase (CE10345) and the aspartic proteinase (CE21681) were detected only in cultures grown at the lower temperature as well. A protein with still unknown function (CE05036) was present only in gels from worm samples grown at 25°C. We show for the first time by proteome analyses that cultivation of worms at the lowest temperature of the known physiological range (15°C) already triggers a (weak) stress response in wild‐type animals. This work led to the identification of “internal control proteins” in the wild‐type strain for further characterization of temperature‐sensitive strains using a proteomics approach.
Changes in protein expression profiles in bivalve molluscs (Chamaelea gallina) exposed to four model environmental pollutants
Authors: Rodríguez‐Ortega Manuel J. , Grøsvik Bjørn Einar , Rodríguez‐Ariza Antonio , Goksøyr Anders , López‐Barea Juan
Published: August 2003

Proteomics has been used in the clam Chamaelea gallina as a preliminary screening of changes in protein expression caused by pollutants, potentially useful as new biomarkers. Clams were exposed in water for seven days to four model contaminants, Aroclor 1254, copper(II), tributyltin (TBT), and arsenic(III), and cytosolic fractions were initially analyzed by two‐dimensional (2‐D) electrophoresis in 7 cm IPG strips (pH 4–7). On average, about 1000 spots were resolved and altered expression was qualitatively detected in 9–26 spots per treatment. Aroclor 1254, Cu(II) and As(III) had a mainly upregulating effect, in contrast to TBT. Altered protein expression was confirmed in 18 cm gels (at narrow pH ranges). The 15 spots more drastically altered were excised and analyzed by mass spectrometry (MS), and four proteins were identified. Aroclor 1254 and Cu(II) upregulated putative isoforms of tropomyosin and light chain of myosin. Actin was downregulated by Aroclor and Cu(II) but upregulated by TBT and As(III), while the opposite behavior was shown by a truncated actin form, homologous to the Drosophila act87E gene product. The exclusive identification of cytoskeletal proteins could reflect their relative abundance, their prevalence in databases in molluscs, or their role as major targets of pollutant‐related oxidative stress.