bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of design and operation parameters on the flow pattern of submerged filters
Authors: Fdez‐Polanco Fernando , García Pedro , Villaverde Santiago 
Published: May 2005

AbstractThe 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

AbstractThe 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

AbstractTen 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

AbstractAdsorptive 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

AbstractTwo 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

AbstractSuspension 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

AbstractExperimental 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

AbstractThe 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

AbstractContinuous 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

AbstractThe 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

AbstractDynamic 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.
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

AbstractA 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

AbstractTen 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

AbstractThe 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

AbstractTrichloroacetic 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

AbstractAn 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

AbstractA 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

AbstractIn 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

AbstractAn 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

AbstractThe 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

AbstractHydropathic 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

AbstractPurposeTo 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 MethodsDynamic 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.ResultsA 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.ConclusionThe 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.