bluuebunny/crossref_metadata_2025_split huggingface dataset:
A fundamental analysis of continuous flow bioreactor and membrane reactor models with death and maintenance included
Authors: Nelson Mark Ian , Kerr Tara Bridget , Chen Xiao Dong 
Published: December 2007

AbstractIn this research we analyse the steady‐state operation of a continuous flow bioreactor, with or without recycle, and an idealised, or non‐idealised, continuous flow membrane reactor. The reaction is assumed to be governed by the well‐known Monod growth kinetics. We show that a flow reactor with idealised recycle has the same performance as an idealised membrane reactor and that the performance of a non‐idealised membrane reactor is identical to an appropriately defined continuous flow bioreactor with non‐idealised recycle. The performance of all three reactor types can therefore be obtained by analysing a flow reactor with recycle. The steady‐states of the recycle model are found and their stability determined as a function of the residence time. The performance of the reactor at large residence times is obtained. In the limit, as the residence time becomes very large, all three reactor configurations have identical performances. Thus the main advantage of using a membrane reactor, or a flow reactor with recycle, for the treatment of industrial wastewaters and slurries is to improve the performance at low residence times. This is quantified for the case of an ideal membrane reactor. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Effects of mixed diluent compositions on poly(vinylidene fluoride) membrane morphology in a thermally induced phase‐separation process
Authors: Li Xianfeng , Xu Guoqiang , Lu Xiaolong , Xiao Changfa 
Published: December 2007

AbstractThe effects of a mixed diluent (MD) composition [dibutyl phthalate/dioctyl phthalate (DOP)] on poly (vinylidene fluoride) (PVDF) membrane morphology were investigated with scanning electron microscopy, and a bicontinuous morphology could be obtained with MD in a thermally induced phase‐separation process. The reasons for the morphology formation were explained according to the effect of MD on the phase diagrams. In addition, the effects of the PVDF concentration on the membrane morphology were examined. For the system with less DOP, the large spherulite morphology was obvious under all investigated concentrations, whereas no large spherulite structure existed in the membrane as the DOP content increased to concentrations other than 20%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Photocure properties of high‐heat‐resistant photoreactive polymers with cinnamate groups
Authors: Kim Whan Gun 
Published: December 2007

AbstractNew high‐heat‐resistant photoreactive polymers with cinnamate groups were synthesized by the reaction of cinnamic acid (CA) and epoxy resins. Their photocure properties were investigated with Fourier transform infrared spectroscopy, UV–visible spectroscopy, and thermogravimetric analysis (TGA). Their photocure reaction rates and the extent of reaction conversion increased with the intensity of UV irradiation. To investigate their photocure reaction kinetics, their reaction conversion rates were plotted against reaction conversion so that their photocure reactions could be analyzed in terms of an nth‐order kinetics reaction equation. The YX4000H–CA photoreactive polymer with a biphenyl moiety, which was expected to have strong molecular interactions, showed a lower reaction conversion rate and reaction constant, and the highest reaction conversion rate and reaction constant was observed in XP2030–CA with an optimum cure reaction space and a reduction of molecular interactions compared with the other photoreactive polymers. Thermal stability was studied by observation of the changes in the transmittance of the photocured polymer films upon heating and by measurement of the weight loss with temperature with TGA. These photoreactive polymers showed good thermal properties, with almost no transmittance change in the visible range even after they were heated at 250°C for 1 h, and they exhibited little weight loss up to about 250°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Novel approach in investigation of the poly(acrylic acid) hydrogel swelling kinetics in water
Authors: Adnadjevic B. , Jovanovic J. 
Published: December 2007

AbstractThe swelling kinetics curves of structurally defined poly(acrylic acid) hydrogel in bidistilled water at temperatures: 25, 30, 35, 40, and 45°C were determined. The possibility of kinetically explaining the isothermal swelling process by applying the following models: reaction controlled by diffusion, first order chemical reaction kinetics, and second order chemical reaction kinetics, was investigated. It was found that kinetically explaining the swelling process using these methods was limited to only certain parts of the process. The swelling process in bidistilled water was described in full range assuming that the hydrogel's swelling rate was a kinetically controlled reaction by the rate of the movement of reactive interface of hydrogel. Based on that model, the kinetic parameters, activation energy (Ea) and preexponential factor (A), of the swelling process were determined to be Ea = 35 kJ/mol and lnA = 8.6. A possible mechanism of the investigated swelling process was discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Moisture absorption and desorption in a UV cured urethane acrylate adhesive based on radiation source
Authors: Wrosch Matt , Xian Guijun , Karbhari Vistasp M. 
Published: December 2007

AbstractA photopolymerizable urethane acrylate (UA) adhesive was cured using two different sources: a conventional UV‐lamp and a UV‐emitting light emitting diode (LED). Moisture uptake in cured specimens was characterized by immersion in deionized water at 21.8, 30, 37.5, and 45°C for a period of 6 months. Additionally, desorption experiments were performed for selected specimens under vacuum at room temperature. Material degradation in the form of mass loss was observed in all samples after attainment of a maximum water uptake level, with the phenomenon being more pronounced at higher immersion temperatures. This degradation is attributed to leaching and dissolution of uncured monomers and lower weight molecular species from the samples. A two stage moisture uptake model is proposed to account for mass loss and excellent agreement between the tested mass loss and the loss‐rate parameters determined from the model is shown. Performance of specimens was characterized with dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). It was found the LED source was not as effective in curing surfaces, due to which there is a higher level of mass and lower Tg from hygrothermal exposure as compared to the core regions of the LED cured specimens and the overall lamp cured specimens. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Total Synthesis of Epohelmin B and Its Analogues
Authors: Fürstner Alois , Korte Alexander 
Published: December 2007

AbstractA concise synthesis of the pyrrolizidine alkaloid epohelmin B (1) and a series of analogues is described. The key steps en route to this lanosterol synthase (oxidosqualene cyclase) inhibitor comprise a highly practical “azonia–Cope rearrangement”, which sets the chiral amine center with excellent optical purity, a ring‐closing metathesis (RCM) reaction catalyzed by a readily prepared and now also commercially available ruthenium–indenylidene complex, a manganese‐catalyzed epoxidation of the resulting eight‐membered cycloalkene derivative, and a nosyl‐deprotection/transannular‐epoxide‐opening cascade to forge the pyrrolizidine core. Digression from the route leading to the natural product in the final stages allowed for the preparation of several “epohelmin‐like” compounds with modified side chains, which is necessary for investigations into a possible functional relationship with other known lanosterol synthase inhibitors.
The assessment of absorption of periplocinin situvia intestinal perfusion of rats by HPLC
Authors: Xie Yue‐Sheng , Ren Xiao‐Liang , Pan Gui‐Xiang , Gao Xiu‐Mei , Liu Chang‐Xiao 
Published: December 2007

AbstractPeriplocin is an important compound of Cortex Periplocae, which shows poor absorption when administered orally. The effective intestinal permeability of periplocin was investigated using single‐pass intestinal perfusion technique in male Wistar rats. SPIP was performed in rat jejunum. The samples of perfusate were collected at the designated time points after rat intestinal perfusion and analyzed by HPLC. The specificity of this method was demonstrated by the absence of interference of the drug peak with the intestinal sac artifacts and the components of the KRB solution. Recovery studies, as well as the intra‐day and inter‐day variations, were within statistical limits. This technique was applied to the study of the intestinal absorption of periplocin. The determined fraction absorbed (Fa) of periplocin was 0.151 ± 0.072 (n= 6) at a concentration of 6 µg/mL; the absorption rate constant (Ka) was 0.0102 ± 0.0039/min and the effective permeability coefficient (Peff) was 0.0021 ± 0.0012 cm/min. These data suggest that periplocin has high permeability and might be absorbed in rat intestine. Copyright © 2007 John Wiley & Sons, Ltd.
Microbial metabolism of loganin by intestinal bacteria and identification of new metabolites in rat
Authors: Li Xiaona , Huo Changhong , Wang Qiao , Zhang Xiaowei , Sheng Xiaona , Zhang Lantong 
Published: December 2007

AbstractLoganin is an important constituent of the traditional Chinese medicine Fructus Corni, with several bioactivities. Microbial metabolism of loganin by intestinal bacteria was investigated. Two metabolites (log‐1 and log‐2) were isolated from anaerobic culture and their structures were identified by means of their ESI‐MS, 1H‐NMR, 13C‐NMR and 2D‐NMR spectral data. Log‐1 was an aglycone of loganin and log‐2 was proved to be a new compound. In vivo metabolites of loganin were detected in rat urine, bile and feces after oral administration of loganin and the structures were proved to be identical with that of the microbial metabolites log‐1 and log‐2 by HPLC–PDA analysis and comparison with the reference standards. Therefore we can prepare metabolites by anaerobic culture with intestinal bacteria. Copyright © 2007 John Wiley & Sons, Ltd.
HPLC assay for determination of amphotericin B in biological samples
Authors: Espada R. , Josa J. M. , Valdespina S. , Dea M. A. , Ballesteros M. P. , Alunda J. M. , Torrado J. J. 
Published: December 2007

AbstractA fast and selective HPLC method for assaying amphotericin B in biological samples was developed and validated. The chromatographic separation was achieved in less than 12 min on a reverse‐phase C18 column using an acetonitrile–acetic acid–water (52:4.3:43.7, v/v/v) mixture as mobile phase. The flow rate was 1 mL/min and the effluent was monitored at 406 nm. A linear response over the concentration range 0.1–10.0 µg/mL was obtained. Intra‐day and inter‐day RSDs were below 5% for all the sample types. This new HPLC method was applied to assay amphotericin B in plasma and several tissue samples such as kidney, liver, spleen and bone marrow. Application of this method to pharmacokinetic studies in mice and dog is provided. Copyright © 2007 John Wiley & Sons, Ltd.
‘It's not racist. It's common sense’. A critical analysis of political discourse around asylum and immigration in the UK
Authors: Capdevila Rose , Callaghan Jane E. M. 
Published: December 2007

AbstractThis paper looks at a political speech given by the leader of the opposition party during the run up to the UK elections in 2005. Using this speech as a starting point, we attempt to trace the path of ‘racism’ within a text that makes explicit claims to being ‘not racist’. Drawing on a number of theoretical and methodological resources, this paper approaches the analysis by focusing on a number of conceptually heterogeneous elements that, in relation with each other, function to produce, re‐produce and stabilize ‘racism’. One of the difficulties commonly encountered in social psychological work, we would suggest, is that an explicit statement of allegiance to a particular methodological and theoretical tradition can also result in a restriction of theorization to a particular ‘level of analysis’. That is to say, a methodological process that constructs a pre‐given category, presets the criteria by which ‘racism’ can be identified and fixes the ‘level of analysis’ at which it can be studied risks ignoring the multiple points of contact at which ‘racism’ can be made visible or made to disappear. The concern here it that such a process can work to reinscribe the very ‘racisms’ we aim to disrupt. Copyright © 2007 John Wiley & Sons, Ltd.
Ambivalent appetites: dissonances in social and medical constructions of anorexia nervosa
Authors: Boughtwood Desiree , Halse Christine 
Published: December 2007

AbstractIt is widely acknowledged that inpatient treatment for anorexia nervosa is largely unsuccessful, with many patients dropping out of treatment or having repeated, failed admissions. Autobiographical and feminist accounts of anorexia suggest that inpatient regimes are reductionist because they focus largely on weight gain. Being fattened up without any attention to the psychic aspects of anorexia can create an ambivalent, uncomfortable body. The paper is based on interviews with 25 adolescent girls1 with a medical diagnosis of anorexia nervosa2 and offers one reading of how girls negotiate hospitalization. Informed by poststructural theory, the transcripts are analysed using a discourse analytic approach to scrutinize the ways in which girls constructed treatment regimes and medical discourses. The focus is two‐fold: girls' engagement with food in the hospital and the dissonance between clinical and social measures of physicality. On the basis of this analysis, the paper offers some suggestions for clinical implications, specifically how hospital regimes might work differently.Girl/s is the term used by the participants in speaking about themselves and others who shared the experience of inpatient treatment with them.
Although anorexia can be a stigmatising label, it is erroneous to do away with the term anorexic as some girls articulated an investment in medicalisation, in being anorexic.
Copyright © 2007 John Wiley & Sons, Ltd.
The Rate‐Determining Step in the Rhodium–Xantphos‐Catalysed Hydroformylation of 1‐Octene
Authors: Zuidema Erik , Escorihuela Laura , Eichelsheim Tanja , Carbó Jorge J. , Bo Carles , Kamer Paul C. J. , van Leeuwen Piet W. N. M. 
Published: December 2007

AbstractThe rate‐determining step in the hydroformylation of 1‐octene, catalysed by the rhodium–Xantphos catalyst system, was determined by using a combination of experimentally determined 1H/2H and 12C/13C kinetic isotope effects and a theoretical approach. From the rates of hydroformylation and deuterioformylation, a small 1H/2H isotope effect of 1.2 was determined for the hydride moiety of the rhodium catalyst. 12C/13C isotope effects of 1.012(1) and 1.012(3) for the α‐carbon and β‐carbon atoms of 1‐octene were determined, respectively. Both quantum mechanics/molecular mechanics (QM/MM) and full quantum mechanics calculations were carried out on the key catalytic steps, for “real‐world” ligand systems, to clarify whether alkene coordination or hydride migration is the rate‐determining step. Our calculations (21.4 kcal mol−1) quantitatively reproduce the experimental energy barrier for CO dissociation (20.1 kcal mol−1) starting at the (bisphosphane)RhH(CO)2 resting state. The barrier for hydride migration lies 3.8 kcal mol−1 higher than the barrier for CO dissociation (experimentally determined trend ∼3 kcal mol−1). The computed 1H/2H and 12C/13C kinetic isotope effects corroborate the results of the energy analysis.
Magnetisierbare Funktionspartikel für die festphasenunterstützte Synthese am Beispiel einer Transferhydrierungsreaktion
Authors: Hickstein B. , Cecilia R. , Kunz U. , Peuker U. A. , Kirschning A. 
Published: December 2007

AbstractMagnetische Funktionspartikel, sogenannte Magnetic Beads, die bereits in der analytischen Biotechnologie ihre Anwendung finden, werden auf Ihre Eignung als Katalysatormaterial untersucht. Die Ionentauscherfunktion der Magnetic Beads soll als katalytisch aktives Material in einer Transferhydrierungsreaktion genutzt werden. Für die Herstellung der magnetischen Funktionspartikel wird ein neuer Syntheseweg eingesetzt, der nach einem Baukastenprinzip funktioniert. In einem Sprühprozess wird aus einer Dispersion/Lösung, die magnetisierbare Nanopartikel, nanoskalige funktionale Ionentauscherpartikel und ein gelöstes Matrixpolymer enthält, in einem Schritt das Funktionspartikel hergestellt. Für die Transferhydrierung wurden reaktionstechnische Untersuchungen unter Verwendung der magnetisierbaren Funktionspartikel in einem Rührkesselreaktor durchgeführt. Diese Daten werden mit in konvektiv durchströmten Komposit‐Mikroreaktoren erhaltenen verglichen.
A Composite Model for hERG Blockade
Authors: Kramer Christian , Beck Bernd , Kriegl Jan M. , Clark Timothy 
Published: December 2007

AbstracthERG blockade is one of the major toxicological problems in lead structure optimization. Reliable ligand‐based in silico models for predicting hERG blockade therefore have considerable potential for saving time and money, as patch‐clamp measurements are very expensive and no crystal structures of the hERG‐encoded channel are available. Herein we present a predictive QSAR model for hERG blockade that differentiates between specific and nonspecific binding. Specific binders are identified by preliminary pharmacophore scanning. In addition to descriptor‐based models for the compounds selected as hitting one of two different pharmacophores, we also use a model for nonspecific binding that reproduces blocking properties of molecules that do not fit either of the two pharmacophores. PLS and SVR models based on interpretable quantum mechanically derived descriptors on a literature dataset of 113 molecules reach overallR2values between 0.60 and 0.70 for independent validation sets andR2values between 0.39 and 0.76 after partitioning according to the pharmacophore search for the test sets. Our findings suggest that hERG blockade may occur through different types of binding, so that several different models may be necessary to assess hERG toxicity.
Estimation of surface roughness (z0) over a stabilizing coastal dune field based on vegetation and topography
Authors: Levin Noam , Ben‐Dor Eyal , Kidron Giora J. , Yaakov Yaron 
Published: December 2007

AbstractAccurate knowledge of the surface roughness and the resultant wind speed are important for many applications, such as climatic models, wind power meteorology, agriculture and erosion hazards, especially on sand dunes in arid and semi‐arid environments, where vegetation cover is scarce. In this study we aimed at quantifying the effects of vegetation cover and topography on surface roughness over a stabilizing dune field on the southern coast of Israel. Forty‐six wind measurements were made at various distances from the coastline, ranging from 10 to 2800 m, and z0 values were calculated from the wind measurements based on the ratio between the wind gust and the average wind speed. We estimated vegetation cover using the soil adjusted vegetation index (SAVI) from Landsat satellite images for the upwind sector at various lengths, ranging from 15 to 400 m, and based on digital elevation models and differential GPS field measurements we calculated the topographic variable of the relative heights of the stations. z0 values were positively correlated with the winter SAVI values (r = 0·87 at an upwind length of 200 m) and negatively correlated with the relative height (r = −0·68 at an upwind length of 200–400 m for the inland dune stations). Using these variables we were able to create a map of estimated z0 values having an accuracy of over 64%. Such maps provide a better understanding of the spatial variability in both wind speed and sand movement over coastal dune areas. Copyright © 2007 John Wiley & Sons, Ltd.
Numerical simulation of viscous flow interaction with an elastic membrane
Authors: Matthews Lisa A. , Greaves Deborah M. , Williams Chris J. K. 
Published: December 2007

AbstractA numerical fluid–structure interaction model is developed for the analysis of viscous flow over elastic membrane structures. The Navier–Stokes equations are discretized on a moving body‐fitted unstructured triangular grid using the finite volume method, taking into account grid non‐orthogonality, and implementing the SIMPLE algorithm for pressure solution, power law implicit differencing and Rhie–Chow explicit mass flux interpolations. The membrane is discretized as a set of links that coincide with a subset of the fluid mesh edges. A new model is introduced to distribute local and global elastic effects to aid stability of the structure model and damping effects are also included. A pseudo‐structural approach using a balance of mesh edge spring tensions and cell internal pressures controls the motion of fluid mesh nodes based on the displacements of the membrane.Following initial validation, the model is applied to the case of a two‐dimensional membrane pinned at both ends at an angle of attack of 4° to the oncoming flow, at a Reynolds number based on the chord length of 4 × 103. A series of tests on membranes of different elastic stiffness investigates their unsteady movements over time. The membranes of higher elastic stiffness adopt a stable equilibrium shape, while the membrane of lowest elastic stiffness demonstrates unstable interactions between its inflated shape and the resulting unsteady wake. These unstable effects are shown to be significantly magnified by the flexible nature of the membrane compared with a rigid surface of the same average shape. Copyright © 2007 John Wiley & Sons, Ltd.
Validation of an in vitro model for assessment of androstenedione hepatotoxicity using the rat liver cell line clone‐9
Authors: Sahu Saura C. , Wiesenfeld Paddy L. , Kim Chung S. , Ross Ivan A. , Sapienza Philip P. , Newell Richard , O'Donnell Michael W. , Flynn Thomas J. 
Published: December 2007

AbstractAndrostenedione, a naturally occurring steroid hormone, has been used to enhance athletic performance. Little is known, however, about its hepatotoxicity. Clone‐9 cells, a non‐transformed epithelial cell line that was originally isolated from normal liver of a 4‐week old Sprague‐Dawley rat, were used as an in vitro model to assess the hepatotoxic potential of androstenedione. The cultures were treated with androstenedione for 24 h at 37 °C in 5% CO2 at concentrations of 0–100 µg ml−1. After the treatment period, the cells and the culture supernatants were assayed for markers of cytotoxicity which included: release of liver enzymes, cell viability, cellular double‐stranded DNA content, oxidative stress, steatosis, cellular ATP content, caspase‐3 activity, the mitochondrial permeability transition and induction of cytochrome P450 activity. Significant concentration‐dependent differences from control were observed in some endpoints at medium concentrations of 10 µg ml−1 and above. These in vitro findings were compared with comparable endpoints obtained from an in vivo study of androstenedione toxicity in female Sprague‐Dawley rats. Of the eight endpoints that could be compared between the two studies, only three (lipid accumulation, ATP depletion and P450 activity) appeared to be concordant. This suggests that, under the experimental conditions used, the clone‐9 cells were not a good model for androstenedione hepatotoxicity. Published in 2007 by John Wiley & Sons, Ltd.