bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Design Imbalance on the Power of the F‐test of a Variance Component in the One‐Way Random Model
Authors: Lee Juneyoung 
Published: March 2003

AbstractThe ANOVA‐based F‐test used for testing the significance of the random effect variance component is a valid test for an unbalanced one‐way random model. However, it does not have an uniform optimum property. For example, this test is not uniformly most powerful invariant (UMPI). In fact, there is no UMPI test in the unbalanced case (see Khuri, Mathew, and Sinha, 1998).The power of the F‐test depends not only on the design used, but also on the true values of the variance components. As Khuri (1996) noted, we can gain a better insight into the effect of data imbalance on the power of the F‐test using a method for modelling the power in terms of the design parameters and the variance components. In this study, generalized linear modelling (GLM) techniques are used for this purpose. It is shown that GLM, in combination with a method of generating designs with a specified degree of imbalance, is an effective way of studying the behavior of the power of the F‐test in a one‐way random model.
Determination of laccase activity in mixed solvents: Comparison between two chromogens in a spectrophotometric assay
Authors: Cantarella Gaetano , d'Acunzo Francesca , Galli Carlo 
Published: March 2003

AbstractSpectrophotometric determination of laccase activity with ABTS acting as chromogen yields exceedingly low values whenever conducted in a water–organic mixed solvent. Nevertheless, there is firm evidence that laccase is able to oxidize substrates such as phenols and amines quantitatively in these mixed solvents. We show that the apparently small rate of ABTS oxidation by laccase in a mixed solvent, such as buffered water–dioxane 1:1, is not amenable to the denaturation of laccase but rather to the decreased stability of ABTS·+. We propose HAA as a more reliable chromogen for the determination of laccase activity in mixed solvents. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 395–398, 2003.
Effect of methanol feeding strategies on production and yield of recombinant mouse endostatin from Pichia pastoris
Authors: Trinh L. B. , Phue J. N. , Shiloach Joseph 
Published: March 2003

AbstractPichia pastoris, a methylotrophic yeast, is an efficient producer of recombinant proteins in which the heterologous gene is under the control of the methanol‐induced AOX1 promoter. Hence, the accepted production procedure has two phases: In the first phase, the yeast utilizes glycerol and biomass is accumulated; in the second phase, the yeast utilizes methanol which is used both as an inducer for the expression of the recombinant protein and as a carbon source. Since the yeast is sensitive to methanol concentration, the methanol is supplied gradually to the growing culture. Three methanol addition strategies were evaluated for the purpose of optimizing recombinant endostatin production. Two strategies were based on the yeast metabolism; one responding to the methanol consumption using a methanol sensor, and the other responding to the oxygen consumption. In these two strategies, the methanol supply is unlimited. The third strategy was based on a predetermined exponential feeding rate, controling the growth rate at 0.02 h−1, in this strategy the methanol supply is limited. Throughout the induction phase glycerol, in addition to methanol, was continuously added at a rate of 1 g L h−1. Total endostatin production was similar in all three strategies, (400 mg was obtained from 3 L initial volume), but the amount of methanol added and the biomass produced were lower in the predetermined rate method. This caused the specific production of endostatin per biomass and per methanol to be 2 times higher in the predetermined rate than in the other two methods, making the growth control strategy not only more efficient but also more convenient for downstream processing. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 438–444, 2003.
High‐density seeding of myocyte cells for cardiac tissue engineering
Authors: Radisic Milica , Euloth Michelle , Yang Liming , Langer Robert , Freed Lisa E. , Vunjak‐Novakovic Gordana 
Published: March 2003

AbstractTissue engineering of 1‐ to 5‐mm‐thick, functional constructs based on cells that cannot tolerate hypoxia for prolonged time periods (e.g., cardiac myocytes) critically depends on our ability to seed the cells at a high and spatially uniform initial density and to maintain their viability and function. We hypothesized that rapid gel–cell inoculation in conjunction with direct medium perfusion through the seeded scaffold would increase the rate, yield, viability, and uniformity of cell seeding. Two cell types were studied: neonatal rat cardiomyocytes for feasibility studies of seeding and cultivation with direct medium perfusion, and C2C12 cells (a murine myoblast cell line) for detailed seeding studies. Cells were seeded at densities corresponding to those normally present in the adult rat heart ([0.5–1] × 108 cells/cm3), into collagen sponges (13 mm × 3 mm discs), using Matrigel® as a vehicle for rapid cell delivery. Scaffolds inoculated with cell–gel suspension were seeded either in perfused cartridges with alternating medium flow or in orbitally mixed Petri dishes. The effects of seeding time (1.5 or 4.5 h), initial cell number (6 or 12 million cells per scaffold), and seeding set‐up (medium perfusion at 0.5 and 1.5 mL/min; orbitally mixed dishes) were investigated using a randomized three‐factor factorial experimental design with two or three levels and three replicates. The seeding cell yield was consistently high (over 80%), and it appeared to be determined by the rapid gel inoculation. The decrease in cell viability was markedly lower for perfused cartridges than for orbitally mixed dishes (e.g., 8.8 ± 0.8% and 56.3 ± 4%, respectively, for 12 million cells at 4.5 h post‐seeding). Spatially uniform cell distributions were observed in perfused constructs, whereas cells were mainly located within a thin (100–200 μm) surface layer in dish seeded constructs. Over 7 days of cultivation, medium perfusion maintained the viability and differentiated function of cardiac myocytes, and the constructs contracted synchronously in response to electrical stimulation. Direct perfusion can thus enable seeding of hypoxia‐sensitive cells at physiologically high and spatially uniform initial densities and maintain cell viability and function. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 403–414, 2003.
Accelerated process development for protease production in continuous multi‐stage cultures
Authors: Raninger A. , Steiner W. 
Published: March 2003

AbstractA fermentation process was developed and optimized for the production of a specific protease from Bacillus licheniformis PWD‐1. Media formulations were constructed and crucial environmental parameters were optimized to enhance growth and product formation. Process dynamics of substrate consumption, biomass‐, product‐, as well as by‐product formation were determined under controlled conditions in a bioreactor. Using kinetic data from batch‐ and continuous‐culture experiments, a fed‐batch process was developed producing proteolytic activities 10 times those found during regular batch culture. In one stage continuous stirred tank culture protease formation was completely decoupled from sporulation. Shift experiments in one‐stage continuous cultures led to the development of a two‐stage continuous stirred tank fermentation process using optimized conditions for growth in the first stage and protease formation in the second stage. Accordingly, the basis for a continuous production of the enzyme on a pilot scale was accomplished. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 517–524, 2003.
Expression and characterization of a humanized cocaine‐binding antibody
Authors: Redwan El‐Rashdy M. , Larsen Nicholas A. , Zhou Bin , Wirsching Peter , Janda Kim D. , Wilson Ian A. 
Published: March 2003

AbstractThe murine immunoglobulin G (IgG) cocaine‐binding monoclonal antibody (mAb), GNC92H2, is notable for its exquisite specificity for cocaine, as opposed to chemically‐related cocaine metabolites, and for its moderately high affinity (Kd ≈ 200 nM) for cocaine. Recently, we described the crystal structure of a mouse/human chimeric Fab construct at 2.3 Å resolution. Herein, we report the successful framework humanization of a single‐chain Fv (scFv) GNC92H2 construct without loss of affinity for cocaine. In brief, we compared the mAb GNC92H2 sequence to human antibody sequences, and used structure‐based design to incorporate mutations (total = 49) that would humanize the framework region without affecting the overall shape of the binding pocket or the key cocaine‐contact residues. The codons of the rationally designed sequence were optimized for E. coli expression, and the gene was synthesized by a de novo PCR reaction using 14 overlapping primers. Expression of the scFv construct was significantly improved in E. coli by fusion to thioredoxin. Intriguingly, this construct apparently refolds to form soluble active antibody in the reducing environment of the cytoplasm. Competitive ELISA and equilibrium dialysis demonstrated comparable binding activity between the humanized scFv and the whole IgG. The successful humanization of mAb GNC92H2 should enhance its potential therapeutic value by reducing its overall. immunogenicity. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 612–618, 2003.
Measurement of trehalose loading of mammalian cells porated with a metal‐actuated switchable pore
Authors: Acker Jason P. , Lu Xiao‐ming , Young Vernon , Cheley Stephen , Bayley Hagan , Fowler Alex , Toner Mehmet 
Published: March 2003

AbstractEfforts to improve the tolerance of mammalian cells to desiccation have focused on the role that sugars have in protecting cells from lethal injury. Among the key determinants of desiccation tolerance is the intracellular trehalose concentration, and thus quantifying the amount and rate of trehalose accumulation has now become very critical to the success of these desiccation approaches. We introduced trehalose into 3T3 fibroblasts, human keratinocytes, and rat hepatocytes using a genetically engineered mutant of the pore‐forming α‐hemolysin from Staphylococcus aureus. Manipulating the extracellular Zn2+ concentration selectively opens and closes this pore (∼2 nm) and enables controlled loading of cells with sugars. We quantified intracellular trehalose using gas chromatography–mass spectroscopy (GC‐MS) to examine the trimethylsilyl derivative of intracellular trehalose. Using the GC‐MS method, we demonstrate that the switchable characteristics of H5 α‐hemolysin permit controlled loading of the high concentrations of trehalose (up to 0.5 M) necessary for engineering desiccation tolerance in mammalian cells. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 525–532, 2003.
Oil/water and pre‐emulsified oil/water (PIT) dispersions in a stirred vessel: Implications for fermentations
Authors: Erler S. T. , Nienow A. W. , Pacek A. W. 
Published: March 2003

AbstractThis study examines dispersions of rapeseed oil (RSO) in water by mechanical agitation under conditions mimicking those found in certain antibiotic fermentations; for example, in the presence of air, antifoam, and finely divided CaCO3 particles. A problem with residual oil has been reported for such fermentations, and it has been suggested that the use of pre‐emulsified oil can reduce this problem. Hence, the dispersion of a pre‐emulsified oil produced by the “phase inversion temperature (PIT) method” has been evaluated. In both cases, the volume fraction of oil was 2%. For the RSO systems, a relatively high agitation speed was required to disperse the oil, especially in the presence of the particles and, when the agitation was stopped, separation occurred rapidly. The Sauter mean drop diameters depended on the system, being at an average energy dissipation rate of approximately 0.9 W kg−1, 180 μm for RSO/water, 130 μm for RSO/water(antifoam)/air, 580 μm for RSO/water/CaCO3, and 850 μm for RSO/water(antifoam)/air/CaCO3. For the same four systems, the PIT emulsion, once dispersed, was very stable and the drop size was essentially independent of the operating conditions, with a Sauter mean diameter of ∼0.3 μm. The implications of these findings for fermentations in which oil is used as a carbon source are assessed. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 543–551, 2003.
Photocrosslinked hyaluronic acid hydrogels: Natural, biodegradable tissue engineering scaffolds
Authors: Baier Leach Jennie , Bivens Kathryn A. , Patrick Jr. Charles W. , Schmidt Christine E. 
Published: March 2003

AbstractIdeally, rationally designed tissue engineering scaffolds promote natural wound healing and regeneration. Therefore, we sought to synthesize a biomimetic hydrogel specifically designed to promote tissue repair and chose hyaluronic acid (HA; also called hyaluronan) as our initial material. Hyaluronic acid is a naturally occurring polymer associated with various cellular processes involved in wound healing, such as angiogenesis. Hyaluronic acid also presents unique advantages: it is easy to produce and modify, hydrophilic and nonadhesive, and naturally biodegradable. We prepared a range of glycidyl methacrylate‐HA (GMHA) conjugates, which were subsequently photopolymerized to form crosslinked GMHA hydrogels. A range of hydrogel degradation rates was achieved as well as a corresponding, modest range of material properties (e.g., swelling, mesh size). Increased amounts of conjugated methacrylate groups corresponded with increased crosslink densities and decreased degradation rates and yet had an insignificant effect on human aortic endothelial cell cytocompatibility and proliferation. Rat subcutaneous implants of the GMHA hydrogels showed good biocompatibility, little inflammatory response, and similar levels of vascularization at the implant edge compared with those of fibrin positive controls. Therefore, these novel GMHA hydrogels are suitable for modification with adhesive peptide sequences (e.g., RGD) and use in a variety of wound‐healing applications. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 578–589, 2003.
Controling the rate of protein release from polyelectrolyte complexes
Authors: Kamiya Noriho , Klibanov Alexander M. 
Published: March 2003

AbstractExtended protein release from readily prepared, water‐insoluble complexes with oppositely charged polyions is explored. Using hen egg‐white lysozyme as a model, its sustained release from such complexes with a number of polyanions under physiological conditions has been demonstrated and rationalized. The rate of release varies orders of magnitude and is controlled by the nature of the polyanion (decreasing upon increase in its linear charge density, length, and hydrophobicity) and the complex particle size (the larger the particles, the slower the release). © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 590–594, 2003.
Early indicators of child abuse and neglect: a multi‐professional Delphi study
Authors: Powell Catherine 
Published: March 2003

AbstractThrough the application of the Delphi technique, this study draws on the expertise of British child protection academics and practitioners from a wide range of disciplines in seeking to develop a consensus opinion on possible early indicators of child abuse and neglect. The search for early indicators is described in the context of a secondary preventative approach to the problem of child maltreatment. A very tentative conclusion arising from the study is that the early indicators of child abuse and neglect that achieved consensus of agreement may help in diagnosing child abuse and neglect at an earlier stage, although they are not necessarily diagnostic. Alternative explanations, differential diagnoses and information‐gathering are paramount, as is a willingness and ability to act on concerns. Although great caution is urged, it is suggested that the findings from the study are credible and of interest to those who are working towards more timely recognition and referral of abused and neglected children. Copyright © 2003 John Wiley & Sons, Ltd.
Difficulties with age estimation of internet images of south‐east Asian girls
Authors: Stathopulu Eleni , Antony Hulse J. , Canning David 
Published: March 2003

AbstractCommunity paediatricians are increasingly asked to provide expert opinion on internet child pornography related to ‘sex tourism’, mostly in south‐east Asian countries. The girls involved are often prepubertal, and the main legal question is to establish whether they are under 13 years of age. This paper provides a review of the literature related to this question. Although there are limited data of age of menarche from the countries at risk of ‘sex tourism’, one recent study from the Philippines showed that the mean age of menarche was similar to the mean age of British girls born between 1982 and 1986. There are no data in the above countries on the early pubertal changes in breast development, but studies from India and China suggested that these might be more prolonged than for British girls. In particular, the interval between B2 stage (early pubertal breast development) and menarche was nearly 3 years in these developing countries, compared with 2 years for the British girls. Maternal malnutrition and girls small for gestational age at birth resulted in an earlier menarche, while chronic malnutrition, severe enough to cause stunting in preschool years, caused a delay in menarche. Taking into account information from the existing studies, we estimated that 97.5% of south‐east Asian girls will show pubertal changes of B2 stage by the age of 13.7 years. Copyright © 2003 John Wiley & Sons, Ltd.
Cover Picture: NMR Structure of the Single QALGGH Zinc Finger Domain from the Arabidopsis thaliana SUPERMAN Protein (ChemBioChem 2‐3/2003)
Authors: Isernia Carla , Bucci Enrico , Leone Marilisa , Zaccaro Laura , Di Lello Paola , Digilio Giuseppe , Esposito Sabrina , Saviano Michele , Di Blasio Benedetto , Pedone Carlo , Pedone Paolo V. , Fattorusso Roberto 
Published: March 2003

AbstractThe cover picture shows the NMR structure of the SUPERMAN zinc finger domain, which is the first high‐resolution structure of a classical zinc finger domain from a plant protein. The structure consists of a very well‐defined ββα motif, typical of all the other Cys2–His2 zinc fingers so far structurally characterized. As a consequence, the QALGGH sequence, which is highly conserved in plant protein classical zinc finger domains, is located at the N terminus of the α helix. Interestingly, this domain region, in animal protein zinc fingers, is constituted of hypervariable residues deputed to the recognition of the DNA bases. Therefore, a peculiar DNA recognition code for the QALGGH zinc finger domain is proposed in the article by Fattorusso and co‐workers on p. 171 ff.
Modulated Nucleoside Kinases as Tools to Improve the Activation of Therapeutic Nucleoside Analogues
Authors: Monnerjahn Christian , Konrad Manfred 
Published: March 2003

AbstractThe use of nucleoside analogues in anticancer and antiviral treatments is often impaired by the slow intracellular activation of these drugs. This problem can be addressed by the modulation of rate‐limiting enzymes in the activation pathways of the nucleoside analogues. Therapeutic strategies based on the combination of optimized activating enzymes and established nucleoside drugs promise significant improvements to traditional chemotherapy.
Solid‐Phase Synthesis and Biological Activity of a Thioether Analogue of Conotoxin G1
Authors: Bondebjerg Jon , Grunnet Morten , Jespersen Thomas , Meldal Morten 
Published: March 2003

AbstractA bicyclic thioether analogue of α‐conotoxin G1, a neurotoxin found in the venom of cone snails, was synthesized on solid phase. Two successive intramolecular on‐bead cyclizations between a cysteine residue and a chloroacetylated reduced peptide bond are the key steps in the synthesis. The first reduced peptide bond was introduced by a reductive alkylation with a 9‐fluorenylmethoxycarbonyl protected amino aldehyde, and the second by coupling of a dipeptide building block containing an allyloxycarbonyl protected reduced peptide bond. The desired bicyclic product was obtained as a mixture of two isomers, which were evaluated for their ability to inhibit the muscular nicotinic acetylcholine receptor expressed in Xenopus oocytes. The two isomers were found to have IC50 values (inhibitory activities) of 144 μM and 48 μM, compared to 0.18 μM for native conotoxin G1.
Behavior Of Silica Aerogel Networks as Highly Porous Solid Solvent Media for Lipases in a Model Transesterification Reaction
Authors: El Rassy H. , Perrard A. , Pierre A. C. 
Published: March 2003

AbstractHighly porous silica aerogels with differing balances of hydrophobic and hydrophilic functionalities were studied as a new immobilization medium for enzymes. Two types of lipases from Candida rugosa and Burkholderia cepacia were homogeneously dispersed in wet gel precursors before gelation. The materials obtained were compared in a simple model reaction: transesterification of vinyl laurate by 1‐octanol. To allow a better comparison of the hydrophobic/hydrophilic action of the solid, very open aerogel networks with traditional organic hydrophobic/hydrophilic liquid solvents, this reaction was studied in mixtures containing different proportions of 2‐methyl‐2‐butanol, isooctane, and water. The results are discussed in relation to the porous and hydrophobic nature of aerogels, characterized by nitrogen adsorption. It was found that silica aerogels can be considered as “solid” solvents for the enzymes, able to provide hydrophobic/hydrophilic characteristics different from those prevailing in the liquid surrounding the aerogels. A simple mechanism of action for these aerogel networks is proposed.
Neuro‐Fuzzy Control of a Continuous Cooled MSMPR Crystallizer
Authors: Bravi M. , Chianese A. 
Published: March 2003

AbstractThis work deals with the design and application of a neuro‐fuzzy controller of the magma density of the fine crystals for the stabilisation of the crystal size distribution (CSD) of the product from an MSMPR (Mixed Suspension, Mixed Product Removal) continuous crystallizer. The cooling crystallization of potassium sulphate from aqueous solutions in a pilot‐scale stirred vessel was investigated. A control strategy, based on the elimination of fines by using a combined sedimentation‐dissolution device, is presented. The control scheme was successfully applied to a pilot‐scale draft‐tube (DT) crystallizer and yielded promising results. The proposed process control system allowed the reduction of the fines fraction by more than 30 %, while maintaining operation stability and short transient responses.