bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular cloning of a novel myeloid granule protein
Authors: Moscinski Lyn N. C. , Hill Bobbye
Published: May 2005

Granulocytes are recognized by the presence of granules, including primary (azurophilic) and secondary types. Each granule ype contains distinct and characteristic families of enzymes. We have secreened a murine bone marrow cDNA library to obtain a series of sequences corresponding to mRNAs which are both myeloid‐specific and appear to be expressed only in immature bone marrow cells. A 1, 160 bp sequence (B9) has been isolated which shows restricted expression in murine bone marrow, with the highest levels in cultures enriched for promyelocytes. Translation yields a single open reading frame of 167 amino acids and a calculated MW of 19.33 kd. A single potential N‐glycosylation site is present. Evaluatin of the amino terminal sequence shows 2 polar amino acids flanking a hydrophobic region, suggesting a signal sequence and possibility of post‐translational modification. An extensive search of the protein data base reveals 30% identity over 90 amino acids with porcine cathelin, a cystain‐like systeine proteinase inhibitor. This sequence identity includes conservation of the 4 cysteine residues noted in all members of the cystain superfamily. In an attempt to further characterize this novel sequence, a polyclonal antiserum was prepared by immunization with a 20 amino acid synthetic peptide corresponding to a unique portion of the carboxy terminus. Immunoelectron microscopy localized B9 to neutrophilic granules. We have identified a novel myeloid‐specific granule protein related to porcine cathelin, but showing important structural differences. This may represent this first isolated member of a new cystatin family. More importantly, the small size of the B9 gene and its tight pattern of early expression make B9 an excellent reporter molecule for the study of new factors important in myeloid differentiation. © 1995 Wiley‐Liss, Inc.
rHox: A homeobox gene expressed in osteoblastic cells
Authors: Hu Yunshan , Flanagan Judith , Brennan Denise P. , Zhou Hong , Ng Kong Wah , Eisman John A. , Morrison Nigel A.
Published: May 2005

Homeodomain proteins are characterized by a conserved domain with a helix‐turn‐helix motif. These proteins act as regulatory factors in tissue differentiation and proliferation. However, their role in the regulation of osteoblast differentiation is unknown. In this study we have identified and characterized a homeobox gene in osteoblast‐like cells. This gene, termed rHox, was isolated from a cDNA library derived from rat osteoblast‐like cells. The nucleotide sequence of the 1,375 base pair (bp) cDNA contains a noncoding leader sequence of 329 bp, a 735 bp open reading frame, and 312 bp of 3′ noncoding sequence. Sequence comparison demonstrates that rHox is identical to the mouse Pmx gene (also called MHox) at the amino acid level and 90% homologous at the nucleotide level. Both Southwestern blotting and gel shift analyses indicate that rHox has potential to bind both the collagen l α 1 and the osteocalcin promoters. Transfection experiments using an rHox expression vector showed a strong repression of target promoter activity, regardless of whether the target promoters contained homeodomain binding reponse elements. These data suggest that rHox is a potent negative regulator of gene expression, although the specific role of rHox in bone gene regulation remains to be determined. © 1995 Wiley‐Liss, Inc.
Human myeloid cell nuclear differentiation antigen binds specifically to nucleolin
Authors: Xie Jingping , Briggs Judith A. , Olson Mark O. J. , Sipos Katalin , Briggs Robert C.
Published: May 2005

The human myeloid cell nuclear differentiation antigen (MNDA) is a nuclear protein expressed specifically in cells of the myelomonocytic lineage and regulated by interferon α in a cell‐specific fashion. MNDA is also a member of a family of interferon‐regulated genes of unknown function. In an effort to elucidate the function of MNDA, three techniques (affinity purification, coimmunoprecipitation, and protein blot assay) were used to characterize its specific protein binding activities. Microsequence analysis showed that MNDA bound the 100 kDa nucleolin protein. The identification of nucleolin was confirmed by immunoreaction with specific antibodies. MNDA contains motifs which could account for specific binding to nucleolin. Nucleolin binds other macromolecules and exhibits features consistent with roles in signal transduction, production of ribosomes, nuclear matrix structure, and regulation of transcription. The present results indicate that the function of MNDA is most likely related to interactions with other proteins. Through these associations, MNDA could contribute cell/lineage‐ and differentiation‐specific limits to the function of ubiquitous proteins such as nucleolin. Further analysis of MNDA protein binding could be critical to elucidating the function of MNDA and could contribute to understanding the fuction of the products of other members of this interferon‐inducible family of genes. © 1995 Wiley‐Liss, Inc.
Simultaneous solvent extraction of cobalt and magnesium in the presence of nickel from sulfate solutions by Ionquest 801
Authors: Tsakiridis Petros E , Agatzini‐Leonardou Stella
Published: May 2005

The simultaneous extraction of Co(II) and Mg(II) from nickel sulfate solutions has been carried out using the organophosphonic extractant Ionquest 801 diluted in Exxsol D‐80. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the solvent extraction parameters, which were the extraction pH at equilibrium, the temperature, the extractant concentration and the organic/aqueous phase ratio. A statistically designed experiment was also carried out to study the stripping of the Ionquest 801 organic phase loaded with cobalt and magnesium by sulfuric acid solution. The number of stages required for both extraction and stripping processes of cobalt and magnesium was evaluated. The results of continuous counter‐current mini‐plant tests demonstrated the simultaneous recovery of cobalt and magnesium from nickel sulfate solution. Copyright © 2005 Society of Chemical Industry
Purification and renaturation of recombinant human lymphotoxin (tumour necrosis factor beta) expressed in Escherichia coli as inclusion bodies
Authors: Jin Hong , Uddin Mohammad S. , Huang Yu L. , Teo Wah K.
Published: May 2005

High level expression of recombinant human tumour necrosis factor β (rh TNF‐β) in Escherichia coli results in the formation of two portions of protein, namely soluble active protein and insoluble protein which is inactive and aggregates in the form of inclusion bodies (IBs). In this study, a procedure for purification and renaturation of rh TNF‐β from inclusion bodies has been designed and verified experimentally with a product purity of more than 90% and a recovery of about 30%. The procedure includes washing of IBs with specific wash buffer (Triton X‐100/EDTA/lysozyme/PMSF), their solubilization with 8 mol dm−3 alkaline urea, purification with ion‐exchange columns, refolding with renaturation buffer and finally concentration and desalination with an ultrafiltration membrane. The characteristics of the renatured protein were identical with those of purified protein from the soluble fraction as demonstrated by (1) SDS‐PAGE, (2) cytotoxic activity on mouse L929 cells, (3) N‐terminal amino acid sequence, and (4) gel filtration chromatography.
Hydrolysis of tannery wastes to protein meal for animal feedstuffs: A process and product evaluation
Authors: Montoneri Enzo , Rizzi Giovanni , Rizzi Arnaldo , Mordenti Archimede , Bauli Adriano , Riolfatti Massimo , Pellegrini Laura
Published: May 2005

Hydrolysis of protein solid wastes from tanneries to yield protein meal for animal nutrition has been performed in a pilot assembly designed to process 400 kg h−1 of disposal material under optimum energy consumption and product yield conditions. Evaluation of the significance of amino acid degradation caused by the process, in relation to the product cost and quality in animal nutrition, was the purpose. A nutrition bioassay was carried out to study the incidence of dietary substitution of the above protein meal for soybean meal on growth performance by early weaned piglets. The results show that degradation of serine, proline, arginine and threonine occurs during collagen hydrolysis, and that only the threonine concentration in the product falls below the dietary requirement. However, integration of protein meal diets with the necessary amino acid content may be accomplished cheaply. Compared with other vegetable and animal commercial protein meals, the cost of the product obtained from tanned hides appears competitive. Processing of other tannery disposal material is not recommended, due to the low protein content of the starting material.
Immobilisation of β‐galactosidase onto gelatin by glutaraldehyde and chromium(III) acetate
Authors: Sungur Sibel , Akbulut Ural
Published: May 2005

β‐Galactosidase (EC 3.2.1.23) was immobilised onto a gelatin carrier system by crosslinking. Glutaraldehyde and chromium(III) acetate were used as crosslinking agents. The effect of pH on enzyme activity, kinetic parameters and reusability of the immobilised enzyme were investigated. To obtain a better relative activity, a method was developed and further modified to increase the surface area of the support system by using polyacrylamide. Relative activity enhancement of 68% was achieved in the gelatin–glutaraldehyde system.
FT‐IR studies on the evolution of different phases and their interaction in ferric molybdate—molybdenum trioxide catalysts
Authors: Belhekar Anagha A. , Ayyappan Subbiah , Ramaswamy Arumugamangalam V.
Published: May 2005

Two samples of Fe–Mo catalysts have been prepared from ferric nitrate and ammonium paramolybdate, one following a conventional procedure and the other by a new precipitation procedure in a buffer medium. The evolution of different Fe–Mo phases, from the fresh precipitate to the aged and then to the calcined state, has been followed by FT‐IR spectroscopy. All the spectral vibrations have been related to different coordination spheres of Mo and Fe ions in the samples and a comparison with a commercial catalyst of similar composition has been made. The new preparation procedure leads to small, uniform (0·3 μm size) particles and a homogeneous morphology of phases as seen by scanning electron microscopy. Additionally, a higher surface area (10·3 m2 g−1), lower bulk density (0·66 g cm−3), a methanol conversion efficiency of > 90% and an HCHO selectivity of 95% distinguish this sample from the conventionally prepared one. Better thermal stability of this sample is inferred from the IR spectral and XRD analyses of the heat‐treated (up to 800°C) samples and is related to the interaction between Fe2(MoO4)3 and MoO3 phases.
Interfacial activity and rate of palladium(II) extraction with fluorinated sulphides
Authors: Wisniewski Maciej , Szymanowski Jan , Cote Gérard , Meissner Egbert
Published: May 2005

Two 2‐hydroxyethylalkyl sulphides of which the alkyl chains are highly fluorinated were synthesised and their interfacial activity as well as their ability for extracting palladium(II) were investigated. Such fluorinated compounds adsorb at the toluene/3 mol dm−3 HCl interface more efficiently and effectively than 2‐hydroxyethyldecyl sulphide. It is shown that an increase in the fluorinated alkyl chain length from C7H4F10Cl to C9H4F14Cl has no important effect upon the interfacial activity. The fluorinated sulphides extract palladium(II) more quickly than their non‐fluorinated analogues so that the equilibrium can be reached in 10–30 min. The extraction of palladium(II) is already rapid in a concentration region in which the sulphides do not exhibit a strong adsorption at the interface. The initial extraction rates obtained with the two fluorinated sulphides considered above are comparable to those obtained with more surface active reagents such as 4‐decylphenylamine. Thus, the preadsorption of the fluorinated sulphides is not necessary for obtaining a high extraction rate.
Polymeric molluscicide for controlled release of bayluscide
Authors: Rehab Ahmed , Akelah Ahmed
Published: May 2005

Polymeric molluscicides containing a niclosamide moiety have been prepared by the chemical reactions of the commercial polymers poly(chloromethylstyrene) (2% DVB) and Amberlite IR‐120 (8% DVB) with Bayluscide. The resulting polymers contain the Bayluscide active group either via a covalent bond or through physical interaction with the diethanolamine groups of the modified polymers.

The release rates of niclosamide were determined in different pH media by UV spectrophotometric analyses. The hydrolysis data showed that the release rates are strongly dependent upon the pH of the medium, and the structure and composition of the polymers. The linkage between the polymer and the niclosamide moiety, i.e. the relative effects of covalent bonding against physical interaction of the molluscicide to a polymer substrate, also appeared to be an important factor affecting the rates of release as demonstrated by the resulting differences in the release rates from the different polymeric systems.
Production of β‐glucosidase by Aspergillus niger using carbon sources derived from agricultural wastes
Authors: Martino Angela , Pifferi Pier G. , Spagna Giovanni
Published: May 2005

The effects of various medium carbon sources and salt solutions on the production of β‐glucosidase (βG, EC 3.2.1.21) by Aspergillus niger have been studied. β‐Glucosidase productivity was found to be 50 times greater than that reported previously.1 This higher productivity was achieved by employing a mutant strain of the organism, readily available and inexpensive carbon sources, such as cellulose and orange peel, and a simple nutrient salt solution.
Kinetic analysis of benzyl alcohol oxidation by alcohol oxidase in aqueous—organic two‐phase systems
Authors: Mitarai Hitomi , Kawakami Koei
Published: May 2005

Alcohol oxidase‐catalyzed oxidation of benzyl alcohol to benzaldehyde was studied in three two‐liquid phase systems involving butyl acetate, xylene and n‐decane. A more highly hydrophobic solvent resulted in more favorable partitioning of the substrate into the aqueous phase and less deleterious effect on the enzyme activity. As a result, the overall production of aldehyde was highest with the n‐decane system and lowest with the butyl acetate system. In addition, the organic solvent served as an extractant for the product, which acted both as a competitive inhibitor and as a denaturant of the enzyme. The time courses of benzaldehyde production were simulated by a simple mathematical model assuming Michaelis–Menten kinetics in the aqueous phase, enzyme deactivation by organic solvents and the equilibrium partitioning of the reagents between the two phases.
Preparation of spherically agglomerated crystals of the 3,5‐diglucoside of cyanidin (cyanin)
Authors: Lasagabaster Aurora , Martín Carmen , Goñi M. Mar
Published: May 2005

Suitable proportions of the solvent mixture benzene:methanol:aqueous hydrochloric acid to yield the spherically agglomerated crystals of cyanin have been found. The physicochemical properties and dissolution rate of the agglomerates, in comparison with the crystals obtained by a conventional method, have been analysed. No change in the crystalline form of the basic crystals was found in acid conditions, after agglomeration. The dissolution rate of spherical agglomerates did not decrease as much as predicted from their low specific surface areas because of their improved wettability. The crystallization speed would not only avoid colour loss during the isolation and purification of anthocyanins from their natural sources, but also would increase production, save time and cost. On the other hand, a decrease in the specific surface areas will reduce powder hydroscopicity with subsequent technological and stability advantages.
Dispersion—flocculation studies on a Goethite‐clay system
Authors: Orumwense Osasere Faraday F.
Published: May 2005

Dispersion–flocculation studies on a Goethite–clay system using flocculants were carried out as a function of flocculant concentrations, pH of slurry, time of agitation and dispersant dosage. Also, the effects of pH and polymer concentrations on the adsorption behaviour of the system were investigated. Results show that well flocculated goethite was preferentially obtained from 4% goethite/kaolinite clay suspensions, with 50 ppm causticised starch in the slurry at pH values of 3–11·5 and with 50 ppm polyacrylamide at pH values of 3–8. Good flocs were also obtained on flocculation of the goethite suspension with 50 ppm polyacrylamide at pH values of 5–7, while the kaolinite suspension did not respond to the same dosage of causticised starch in the same pH range. Results further reveal that for the goethite/kaolinite suspension, the best results was obtained with 50 ppm polyacrylamide at pH values of 7–10. Based on the data generated in the study, it was concluded that causticised starch is a better flocculant than polyacrylamide for goethite suspensions although polyacrylamide is an excellent flocculant for kaolinite suspensions.
Adsorption of methylene chloride vapor on activated carbons
Authors: Tsai Wen‐Tien , Chang Ching‐Yuan
Published: May 2005

A laboratory investigation on the adsorption of hazardous methylene chloride (METH) vapor on the commercial activated carbons BPL and PCB, which were made from bituminous coal and coconut shell, respectively, was conducted at 283, 293, 303, and 313 K. The physical properties and surface functional groups of the two activated carbons were also measured and compared with each other. The experimental results indicate that the adsorption capacity of carbon PCB is slightly higher than that of carbon BPL. It was found that the Langmuir, Freundlich, and Dubinin–Radushkevich adsorption equations were well fitted by the measured adsorption data. The values of the parameters of the adsorption equations were determined for the two adsorbents. The physical properties (e.g. micropore volume) of the adsorbents are consistent with the parameters obtained from the adsorption results.
Influence of design and operation parameters on the flow pattern of submerged filters
Authors: Fdez‐Polanco Fernando , García Pedro , Villaverde Santiago
Published: May 2005

The influence of design parameters (height and bed porosity) and operation parameters (liquid and gas superficial velocities) on the flow pattern of an up‐flow biological aerated filter has been studied. A lithium chloride pulse input was used for obtaining residence time distribution curves. Bed height was not found to influence the flow pattern but did increase retention time because of diffusion. Porosity was the controlling factor of the diffusional phenomena and, consequently, also controlled the hydrodynamic performance of the reactor. Thus, the flow pattern approximated more to plug‐flow and retention was greater in lower porosity filters (puzzolana bed) than in higher porosity units (sepiolite bed). The liquid velocity effect was more important than the gas velocity effect.
Enzymatic removal of selected aromatic contaminants from wastewater by a fungal peroxidase from Coprinus macrorhizus in batch reactors
Authors: Al‐Kassim Loola , Taylor Keith E. , Nicell James A. , Bewtra Jatinder K. , Biswas Nihar
Published: May 2005

The use of enzymes such as horseradish peroxidase (HRP) for degrading or removing toxic organics from synthetic wastewater has been demonstrated previously. Potential alternatives to HRP are other peroxidases, various ligninases, haloperoxidases and laccases. Results of this study indicate that a fungal peroxidase from Coprinus macrorhizus (CMP) has the capability to catalyze the same reactions as HRP. Similarly, in batch reactors the trend and removal efficiency of aromatic compounds by CMP from synthetic wastewater depend on the nature of the compound.
Azo disperse dyes for synthetic fibres. 2: Benzimidazole derivatives
Authors: Fadda A. A. , Etman H. A. , Amer F. A. , Barghout M. , Mohamed Kh. S.
Published: May 2005

Ten variously substituted derivatives (IIa–j) of 3′‐(benzimidazol‐2‐yl)‐4′‐hydroxyazobenzene were prepared. The effects of the nature and orientation of the substituents on the colour and dyeing properties of these dyes on polyester and acrylic fibres were evaluated.
Harvesting of Saccharomyces cerevisiae using colloidal gas aphrons
Authors: Save Sanjiv V. , Pangarkar Vishwas G.
Published: May 2005

Adsorptive bubble separation using Colloidal Gas Aphrons (CGA) can be used for harvesting of microorganisms. The effect of various operating parameters, for example pH, biomass loading, dispersed and continuous phase velocity, surfactant type and concentration, has been studied on the recovery of Saccharomyces cerevisiae. The operating conditions were optimised for maximum separation. The results obtained have been compared with the prediction of an model earlier.
Calcium alginate bead manufacture: With and without immobilised yeast. Drop formation at a two‐fluid nozzle
Authors: Gilson Christopher D. , Thomas Adrian
Published: May 2005

Two models were developed to predict the size of drops of aqueous sodium alginate solution formed at a two‐fluid nozzle. Experimental results revealed that actual drop sizes lay between the sizes predicted by the two models. Drop size was closely predicted by the volume mean of the two models. Several nozzles were tested and the influence of operating conditions on drop diameter was examined, with gas velocity and nozzle outer diameter having the largest effect. Only two nozzles would be needed to produce drops with diameters in the range 1–6 mm. The addition of yeast in amounts of up to 10% (w/w) had no effect on operation of the nozzles.
Kinetic analysis for effect of initial substrate concentration on growth and secondary metabolite production in cultures of Nicotiana tabacum
Authors: Shibasaki Namoi , Obika Ryousuke , Yonemoto Toshikuni , Tadaki Teiriki
Published: May 2005

Suspension cultures of tobacco cells were studied using airlift and rotary‐drum bioreactors. The effect of initial concentrations of a major substrate, sucrose, on the growth and production of a secondary metabolite, phenolic compounds, was investigated. The dry weights and total concentrations of the phenolic compounds increased with the initial sucrose concentration in both bioreactors. Both bioreactors were found to have the same tendency for the effect of initial sucrose concentration. The structured model, presented previously was modified by considering that sucrose was hydrolyzed to glucose and fructose by an enzymatic reaction. The previous and the new models were applied to the above two sets of experimental data obtained with two bioreactors, independently. The hydrolysis of sucrose was elucidated to contribute slightly to the overall kinetics of growth and secondary metabolite production in these cultures. Furthermore, the levels of shear damage in each bioreactor were quantitatively compared based on the death rate constant, ki, which is one of the model constants.
Measurement and prediction of pressure drop in two‐phase flow
Authors: Ferguson Michael E. G. , Spedding Peter L.
Published: May 2005

Experimental data for air–water two‐phase co‐current flow in two different pipe diameters were used to test the prediction of pressure drop by a number of existing theories and correlations. Several models are shown to be useful for prediction, particularly with the stratified regimes which have proved difficult to handle in the past. The model suggested by Olujic proved to be of particular value.
Mathematical modelling of the alcoholic fermentation of glucose by Zymomonas mobilis mobilis
Authors: Garro Oscar A. , Rodríguez Emilio , Unda Roberto Palacios , Callieri Danley A. S.
Published: May 2005

The kinetics of alcoholic fermentation of a strain of Zymomonas mobilis, isolated from sugarcane juice, has been studied with the objective of determining the constansts of a non‐structured mathematical model that represents the fermentation process. Assays in batch and in continuous culture have been carried out with different initial concentrations of glucose. The final concentrations of glucose, ethanol and biomass were determined. The following kinetic parameters were obtained: μmax, 0·5 h−1; Ks, 4·64 g dm−3; Pmax, 106 g dm−3; Yx/s, 0·0265 g g−1; m, 1·4 g g−1 h−1; α, 17·38 g g−1; β, 0·69 g g−1 h−1.
The role of continuous culture in modelling the human microflora
Authors: Marsh Philip D.
Published: May 2005

Continuous culture techniques have been applied successfully to the modelling of the microflora at various human sites, but especially the mouth and the colon. Complex microbial communities can be grown satbly and reproducibly for prolonged periods under controlled environmental conditions. Key parameters can then be varied independently so that true cause‐and‐effect relationships can be established. The utility of some models has been increased by (a) the construction of diverse but defined inocula, (b) the use of growth media which reflect the main nutrients of the habitat, (c) the provision of surfaces for biofilm formation, and (d) the use of linked culture vessels (multi‐stage systems) to permit spatial or temporal heterogeneity. Comparisons of the properties of such communities with clinical data have supported the validity of such model systems. Applications of these models have ranged from determining the relative significance of dietary versus endogenous nutrients on community balance and metabolism, to the effect of antmicrobial agents. These modelling studies have enabled significant insights to be made into the functions and properties of the resident human microflora.
Combustion kinetics of agricultural wastes
Authors: Encinar José M. , Beltrán Fernando J. , Ramiro Antonio , González Juan F. , Bernalte Alvaro
Published: May 2005

The combustion of two agricultural residues, grape and olive bagasses, has been studied. The influence of oxygen partial pressure and gas flow rate have been analysed. The analysis of residual gases, mainly containing CO and CO2, shows that there are two successive stages or effects owing to the combustions of volatile compounds and solid. Oxygen partial pressure has a pronounced influence on the temperatures at which combustion effects are observed. In fact, both temperatures of combustion coincide when oxygen partial pressure is higher than 5 × 104 pa. For each run, curves of weight loss and differential weight loss have been followed. From a kinetic model proposed (first and nth reaction order, between 0·87 and 0·84, with respect to the solid and oxygen, respectively), the activation energy of combustion was found to be between 82·6 and 89·3 kJ mol−1
Incorporation of death kinetics into a 2‐dimensional dynamic heat transfer model for solid state fermentation
Authors: Sangsurasak Penjit , Mitchell David A.
Published: May 2005

Dynamic two‐dimensional modelling was used in a theoretical analysis of the overheating problem in solid‐state fermentation within a packed‐bed bioreactor. The model described the growth and death of the fungus Rhizopus oligosporus as functions of temperature; the generation of metabolic heat; and the transfer of heat within the packed‐bed by conduction and convection. The model predicted that convection was the dominant heat transfer mechanism under the design and operational parameters applied. Significant death occurred in the upper region of the bed where the highest temperatures were reached. The temperature rise at the top of the bed could be minimized by using high superficial air velocities or low inlet air temperatures. The most effective strategy for a column with a bed height: bed diameter ratio of 1:1 or less was to use a high superficial air velocity.
Combinatorial chemistry in the discovery and development of drugs
Authors: Doyel Paul M.
Published: May 2005

A Comprehensive review of the tractic and strategies that are available to the drug discovery process using combinatorial techniques.
Performance of a biphasic organic/aqueous hollow fibre reactor using immobilized lipase
Authors: Giorno L. , Molinari R. , Drioli E. , Bianchi D. , Cestic P.
Published: May 2005

A biphasic organic/aqueous membrane bioreactor, which combined chemical reaction with continuous extraction of production in the aqueous phase, was investigated. Lipase from Candida Cylindracea was used as catalyst with the hydrolysis of triglycerides, to fatty acids and glycerol, as a model‐system for studying the optimal operating conditions. Asymmetric capillary membranes, made of polyamide, were used as support for the enzyme, which was immobilized into the sponge layer of the membrane by cross‐flow filtration. The catalytic behavior of lipase, both immobilized in a hydrophilic membrane and free in solution, was compared. The effect of pH, temperature and substrate concentration on reactor performance were studied. The catalytic stability of the immobilized enzyme was improved compared with the enzyme in solution. The immobilized lapse showed no deactivating in an operating period of 16 days whereas lipase in solution gave an 80% decrease in specific activity after 2 days of continuous operation. The specific activity of immobilized lipase was significantly influenced by the amount of enzyme loaded into the membranes. The optimal range of immobilized protein was between 2 and 12 mg cm−3. The positive results obtained with the model‐system were also confirmed using the biphasic organic/aqueous membrane bioreactor in a potential practical application, namely the conversion and separation of one enantiomer from an organic racemic mixture of an ester.
Azo disperse dyes for synthetic fibres IV: Indole derivatives
Authors: Fadda A. A. , Etman H. A. , El‐Desoky S. E. , Bondk S.
Published: May 2005

Ten 4‐arylazo derivatives of 2‐(indol‐2′‐yl)phenol were prepared. The effects of the nature and orientation of the substituents on the colour and dyeing properties of these dyes on polyester, and acrylic fibres were evaluated.
Ultimate resolution in open tubular columns
Authors: de Clerk K. , Smuts T. W. , Buys T. S.
Published: May 2005

The expression for the resolution function, R, in terms of operating parameters for open tubular columns has been extended to include inlet contributions to the peak variance. Subsequent optimization has revealed the existence of optima in the column radius, the stationary phase thickness and the diffusion coefficient ratio in the stationary and mobile phases‐in addition to the well‐known optimum in the flow velocity. This implies that R at optimum becomes R=f(K)L0.6Vi−0.2, i.e. a function only of the column length, L, the inlet volume, Vi, and the concentration distribution coefficient, K. For given K, L and Vi all other parameters such as retention time and pressure drop can thus be directly computed. The information is finally consolidated in the form of contour diagrams. The text itself is cast in the form of a science fantasy.
Trichloroacetic acid in the foliage of forest trees
Authors: Frank Hartmut , Vincon Antje , Reiss Johannes , Scholl Harald
Published: May 2005

Trichloroacetic acid (TCA) is an atmospheric oxidation product of airborne C2‐chlorocarbons and a widespread air pollutant. It was widely used as a herbicide in the fifties and sixties, in some countries, still today. It occurs in the foliage of conifers and deciduous trees of mountain forests in Germany, e. g. the Black Forest, the Northern Alps or the Erzgebirge. Quantitative determination in the ppb‐range is achieved by gas chromatography using thick film capillary columns and electron‐capture detection. The levels in spruce needles at two forest sites correlate with the extent of needle loss. The data are supportive of the hypothesis that TCA is causally involved in the induction of mountain forest decline.
Thermal degradation observed with different injection techniques: Quantitative estimation by the use of thermolabile carbamate pesticides
Authors: Müller Hans‐Martin , Stan Hans‐Jürgen
Published: May 2005

An experiment has been designed to study the thermal degradation of thermolabile compounds caused by various injection techniques. The four carbamate pesticides aminocarb, bendiocarb, carbaryl, and dioxacarb decompose thermally into methylisocyanate and the corresponding phenol. The carbamets and the phenols arising from them were separated on a 25 m SE‐54 fused silica column; all compounds exhibited sharp peak shape indicating that the degradation observed took place completely within the injector.

When cold on‐column injection was employed no thermal degradation was observed whereas with hot splitless injection at 220°C decomposition of the carbamates was almost complete.

PTV injection was found to produce intermediate results. When packed with glass wool and operated with glass wool and operated with starting temperatures lower than the boiling point of the solvent, decomposition was found to be almost complete. Applying isothermal conditions at 140°C (30°C above the boiling point of toluene) aminocarb and bendiocarb underwent only slight decomposition while carbaryl and dioxacarb were about half degraded. Results from PTV injection with an empty insert resembled those obtained using cold on‐column injection and in this mode the application of temperatures up to 200°C resulted in no visible degradation. This can be explained by the short residence time of the sample in the injector.
Analysis of antiepileptic drugs by capillary gas chromatography with on‐column injection
Authors: Volmut Juraj , Melník Miloslav , Matisová Eva
Published: May 2005

A simple and quick gas chromatographic method has been developed for the determination of up to six commonly used antiepileptic drugs in human serum. The antiepileptics are isolated from serum by solid phase extraction on to a reversed phase sorbent and recovered with ethyl acetate as eluent. The ethyl acetate eluate is suitable for direct on‐column injection on to a phenyl methyl siloxane capillary column; hydrogen is used as carrier gas and the compounds are separated with a two‐ramp temperature program. Detection is by FID.

The reproducibility of the method varies between 2 and 6% RSD, depending on the drug and the level analyzed; limits of detection were found to be 14–51 pg and minimum assayed concentrations in serum were between 14 and 51 ng/ml.
Erosion of efficiency in non‐uniform linear chromatography
Authors: Blumberg Leonid M.
Published: May 2005

In linear chromatography (i.e. chromatography performed in the absence of sample overloading), when the plate height of a column is roughly uniform along its length, variations in the velocities of solutes are the only possible causes of erosion of efficiency. The sources of these variations (variations in capacity ratio and in the density of the mobile phase, etc.) play no direct role in the erosion of efficiency except through their effect on solute velocities. In other words, what eventually causes the erosion of efficiency is merely variation in the time required for solutes to traverse equally small segments of a column. Significant erosion can only arise from abrupt and deep deceleration of solutes in one or several relatively small segments of a column.

If erosion of efficiency caused by pressure gradients in linear SFC is to be large, the depth and the sharpness of the deceleration of a solute must go beyond that hitherto confirmed experimentally. Many relevant examples are analyzed graphically.
Application of HPLC‐PBMS to the identification of unknown components in a triterpenoid fraction of Arbutus unedo fruits
Authors: Gaspar Elvira M. S. M. , das Neves Higuinaldo J. Chaves , Noronha João P.
Published: May 2005

An extract fraction fruits of Arbutus unedo, L., was cleaned‐up by column chromatography and shown by NMR to be a mixture of isomers that resists further attempts at separation by conventional chromatographic methods. High resolution gas chromatography‐mass spectrometry (HRGC‐MS) confirms the presence of triter‐penoid isomers but does not allow separation of all the components. This can be improved by trimethylsilylation but the absence of molecular ions and the complex spectra are difficult to interpret. Complete separation can be achieved by high pressure liquid chro‐matography (HPLC) coupled to a mass spectrometer by means of a particle beam interface (HPLC‐PBMS). Four triterpene com‐pounds are identified through analysis of the corresponding mass spectra: α‐amyrin, β‐amyrin, and Lupeol, have for the first time been identified in Arbutus unedo, L. Fruits. A new natural triterpene tentatively identified as olean‐12‐en‐3β, 23‐diol is described for the first time.
SFE of rosemary oil: Assessment of the influence of process variables and extract characterization
Authors: Coelho Luiz A. F. , Oliveira José V. , D'Ávila Saul G. , Vilegas Janete H. Y. , Lanças Fernando M.
Published: May 2005

The effects of temperature and solvent density on the characteristics of the extracts obtained from supercritical fluid extraction (SFE) of the volatile compounds from Brazilian rosemary (Rosamarinus officianalis L., Labiatae) using carbon dioxide (CO2) as solvent were investigated. The experiments were performed in a semi‐batch laboratory scale home‐made unit at two temperatures, viz. 310.15 and 320.15 K, over the pressure range of 100‐160 bar. This study allowed to determine the crossover point and the maximum solubility of the oil. The products were analyzed by HRGC‐MS, and compounds grouped in three different classes according to their molecular mass distribution in order to evaluate the influence of the variables studied on the characteristics of the extracts. The model proposed by Sovová was adopted in an attempt to interpret the mass transfer phenomena in the extraction process.
Prediction of homologous binding sites on RB and p107 common for viral oncoproteins and cellular ligands
Authors: Wendtner Clemens M. , Radulescu Razvan T.
Published: May 2005

Hydropathic anticomplementarity of amino acids specifies that peptides translated from complementary DNA strands may acquire amphiphlic conformations and bind to each other. This concept has been coined ‘Molecular Recognition Theory’ (MRT) or ‘complementary peptide theory’. Inactivation of retinoblastoma protein (RB), a tumor suppressor gene product, has been shown to be involved in the pathogenesis of many tumors and to be due to either mutation of the RB gene, hyperphosphorylation or complex formation with viral oncoproteins. The viral oncoproteins share a common RB binding motif with cellular ligands. The exact site on RB associating with this common RB binding motif of viral oncoproteins and cellular ligands has not been identified yet. This study is the first to predict putative binding sites on RB and p107, a cellular protein with RB sequence homology, respectively, by using the hydropathic complementarity approach. These sites are residues 649–654 of RB and 657–662 of p107. Moreover, this paper proposes a structure for a potential antineoplastic agent based on the amino acid sequence of the predicted RB binding site. The data presented herein should have important implications both for the understanding of cancer pathophysiology and for the drug design of antineoplastic compounds.
Dynamic susceptibility contrast perfusion imaging of radiation effects in normal‐appearing brain tissue: Changes in the first‐pass and recirculation phases
Authors: Lee Michael C. , Cha Soonmee , Chang Susan M. , Nelson Sarah J.
Published: May 2005

Purpose

To identify radiation‐induced changes in the cerebral vasculature of healthy tissue in the first four months following radiotherapy through the analysis of dynamic‐susceptibility contrast perfusion imaging.

Materials and Methods

Dynamic gradient‐echo imaging was performed on 22 patients during injection of a bolus of Gd‐DTPA contrast. The relative cerebral blood volume (rCBV), maximum ΔR2* of the first passage of the bolus, and a recirculation parameter were derived from gamma‐variate fits of the dynamic data. The white matter (WM) rCBV and peak heights were estimated through correlation with segmented T1‐weighted images. A percent recovery to baseline was also computed to further describe the recirculation phase.

Results

A significant elevation of the recirculation phase was observed at doses > 15 Gy at two months following radiotherapy. This was reflected in an increased recirculation parameter in the fitted curves in the 15–30, 30–45, and >45 Gy dose groups to 2.8%, 3.8%, and 2.4% above the <15 Gy voxels, as well as in a decline in percent recovery to baseline. A trend toward lower rCBV and peak heights was observed at that same time point.

Conclusion

The observed results suggest a dose‐dependent decline in vessel density and increase in vascular permeability and/or tortuosity in irradiated normal‐appearing brain tissue at two months following radiotherapy. J. Magn. Reson. Imaging 2005;21:683–693. © 2005 Wiley‐Liss, Inc.
Spiral imaging: A critical appraisal
Authors: Block Kai Tobias , Frahm Jens
Published: May 2005

In view of recent applications in cardiovascular and functional brain imaging, this work revisits the basic performance characteristics of spiral imaging in direct comparison to echo‐planar imaging (EPI) and conventional rapid gradient‐echo imaging. Using both computer simulations and experiments on phantoms and human subjects at 2.9 T, the study emphasizes single‐shot applications and addresses the design of a suitable trajectory, the choice of a gridding algorithm, and the sensitivity to experimental inadequacies. As a general result, the combination of a spiral trajectory with regridding of the k‐space data poses no principle obstacle for high‐quality imaging. On the other hand, experimental difficulties such as gradient deviations, resonance offset contributions, and concomitant field effects cause more pronounced and even less acceptable image artifacts than usually obtained for EPI. Moreover, when ignoring parallel imaging strategies that are also applicable to EPI, improvements of image quality via reduced acquisition periods are only achievable by interleaved multishot spirals because partial Fourier sampling and rectangular fields of view (FOVs) cannot be exploited for non‐Cartesian trajectories. Taken together, while spiral imaging may find its niche applications, most high‐speed imaging needs are more easily served by EPI. J. Magn. Reson. Imaging 2005;21:657–668. © 2005 Wiley‐Liss, Inc.
Digital subtraction dark‐lumen MR colonography: Initial experience
Authors: Ajaj Waleed , Veit Patrick , Kuehle Christiane , Joekel Michaela , Lauenstein Thomas C. , Herborn Christoph U.
Published: May 2005

Purpose

To evaluate image subtraction for the detection of colonic pathologies in a dark‐lumen MR colonography exam.

Materials and Methods

A total of 20 patients (12 males; 8 females; mean 51.4 years of age) underwent MR colonography after standard cleansing and a rectal water enema on a 1.5‐T whole‐body MR system. After suppression of peristaltic motion, native and Gd‐contrast‐enhanced three‐dimensional T1‐w gradient echo images were acquired in the coronal plane. Two radiologists analyzed the MR data sets in consensus on two separate occasions, with and without the subtracted images for lesion detection, and assessed the value of the subtracted data set on a five‐point Likert scale (1 = very helpful to 5 = very unhelpful). All imaging results were compared with endoscopy.

Results

Without subtracted images, MR‐colonography detected a total of five polyps, two inflammatory lesions, and one carcinoma in eight patients, which were all verified by endoscopy. Using subtraction, an additional polyp was found, and readout time was significantly shorter (6:41 vs. 7:39 minutes; P < 0.05). In two patients, endoscopy detected a flat adenoma and a polyp (0.4 cm) that were missed in the MR exam. Sensitivity and specificity without subtraction were 0.67/1.0, and 0.76/1.0 with the subtracted images, respectively. Subtraction was assessed as helpful in all exams (mean value 1.8 ± 0.5; Likert scale).

Conclusion

We consider subtraction of native from contrast‐enhanced dark‐lumen MR colonography data sets as a beneficial supplement to the exam. J. Magn. Reson. Imaging 2005;21:841–844. © 2005 Wiley‐Liss, Inc.
Proximal pulmonary artery blood flow characteristics in healthy subjects measured in an upright posture using MRI: The effects of exercise and age
Authors: Cheng Christopher P. , Herfkens Robert J. , Taylor Charles A. , Feinstein Jeffrey A.
Published: May 2005

Purpose

To use MRI to quantify blood flow conditions in the proximal pulmonary arteries of healthy children and adults at rest and during exercise in an upright posture.

Materials and Methods

Cine phase‐contrast MRI was used to calculate mean flow and reverse flow index (RFI) in the main (MPA), right (RPA), and left (LPA) pulmonary arteries in healthy children and adults in an open‐MRI magnet equipped with an upright MRI‐compatible ergometer.

Results

From rest to exercise (150% resting heart rate), blood flow (liters/minute/m2) increased in the RPA (1.4 ± 0.3 vs. 2.5 ± 0.4; P < 0.001), LPA (1.1 ± 0.3 vs. 2.2 ± 0.6; P < 0.001), and MPA (2.7 ± 0.5 vs. 4.9 ± 0.5; P < 0.001). RFI decreased in the LPA (0.040 ± 0.030 vs. 0.017 ± 0.018; P < 0.02) and MPA (0.025 ± 0.024 vs. 0.008 ± 0.007; P < 0.03). Adults experienced greater retrograde flow in the MPA than the children (0.042 ± 0.029 vs. 0.014 ± 0.012; P < 0.02).

Conclusion

It appears that at both rest and during exercise, in children and adults alike, RPA/LPA mean blood flow distribution is predominantly determined by distal vascular resistance, while retrograde flow is affected by proximal pulmonary bifurcation geometry. J. Magn. Reson. Imaging 2005;21:752–758. © 2005 Wiley‐Liss, Inc.
Magnetic resonance techniques for the in vivo assessment of multiple sclerosis pathology: Consensus report of the white matter study group
Authors: Filippi Massimo , Falini Andrea , Arnold Douglas L. , Fazekas Franz , Gonen Oded , Simon Jack H. , Dousset Vincent , Savoiardo Mario , Wolinsky Jerry S.
Published: May 2005

On October 9–11, 2003, the third meeting of the White Matter Study Group of the International Society for Magnetic Resonance in Medicine was held in Venice, Italy. This article is the report of the meeting on how to use MRI in the diagnostic workup of multiple sclerosis (MS) and allied white matter disorders, and to define the nature and the extent of MS pathology in vivo. Both of these steps are central to the design of future treatment strategies aimed at limiting the functional consequences of the most disabling aspects of this disease. J. Magn. Reson. Imaging 2005;21:669–675. © 2005 Wiley‐Liss, Inc.
Diffusion‐weighted images of the liver: Comparison of tumor detection before and after contrast enhancement with superparamagnetic iron oxide
Authors: Naganawa Shinji , Sato Chiho , Nakamura Tatsuya , Kumada Hisashi , Ishigaki Takeo , Miura Shunichi , Maruyama Katsuya , Takizawa Osamu
Published: May 2005

Purpose

To study the recognition of malignant lesions of the liver on diffusion‐weighted images (DWI) can be improved by the administration of superparamagnetic iron oxide (SPIO).

Materials and Methods

Pre‐ and post‐SPIO mediated DWI of the liver was compared in six patients with suspected malignant liver lesions at 1.5 Tesla using a parallel imaging technique.

Results

Post‐SPIO DWI showed improved contrast‐to‐noise ratio between malignant lesions and liver. Furthermore, the spleen signal was decreased on post‐SPIO DWI, thus avoiding the overlap of the spleen and left lobe of the liver on maximum intensity projections (MIP).

Conclusion

Recognition of malignant lesions of the liver was improved by SPIO on DWI. On MIP images of DWI, SPIO helped to decrease the overlap of spleen signal on the liver in some projection angles. J. Magn. Reson. Imaging 2005;21:836–840. © 2005 Wiley‐Liss, Inc.