bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conductance fluctuations and corrections to the localization length in two‐dimensional localized systems
Authors: Prior J. , Somoza A. M. , Ortuño M. 
Published: December 2005

AbstractWe have studied numerically the average and the fluctuations of the conductance in two‐dimensional disordered non‐interacting systems in the localized regime. We have calculated the zero temperature conductance from the Green functions, which can be efficiently obtained propagating strip by strip. We have studied the finite size corrections to the average of the logarithm of the conductance and they turn out to be crucial in the numerical calculation of the localization length. We found that the third moment of the logarithm of the conductance ln g is proportional to 〈ln g〉 for large systems. As the variance goes as 〈ln g〉2/3, we conclude that the distribution of ln g does not tend to a log normal distribution, but to an asymmetric distribution that keeps a constant shape in the limit of large sizes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantitative non‐destructive determination of trace elements in archaeological pottery using a portable beam stability‐controlled XRF spectrometer
Authors: Romano F. P. , Pappalardo G. , Pappalardo L. , Garraffo S. , Gigli R. , Pautasso A. 
Published: December 2005

AbstractA portable beam stability‐controlled XRF spectrometer developed at the LNS/INFN laboratories at Catania (Italy) was used for the non‐destructive determination of some trace elements (Rb, Sr, Y, Zr and Nb) in fine pottery artefacts. The XRF system and the method developed to control the energy and intensity stability of the excitation beam are briefly discussed. Concentrations of Rb, Sr, Y, Zr and Nb were determined in 50 fine potsherds from the votive deposit of San Francesco in Catania by using a multi‐linear regression method. Additionally, in order to test the homogeneity of the material composing the fine pottery samples, a small portion of a few potsherds was powdered and analysed using the XRF system and the multilinear regression method. A comparison between non‐destructive and destructive approaches is presented and discussed. Finally, quantitative XRF data were compared with those obtained by chemical analysis of the powdered samples. The results allowed the testing of a non‐destructive methodology to be used for the identification and grouping of the different typological classes of fine pottery mainly represented in the San Francesco sanctuary. Copyright © 2005 John Wiley & Sons, Ltd.
Theory of two-layer hydraulic exchange flows with rotation
Authors: RIEMENSCHNEIDER ULRIKE , SMEED DAVID A. , KILLWORTH PETER D. 
Published: December 2005

Two-layer rotating exchange flows through channels of rectangular cross-section are modelled using semi-geostrophic, zero-potential-vorticity theory. For a given channel cross-section the full range of possible flow states is considered. The interface always has a uniform slope across the channel, but may separate from one or both of the sidewalls to attach to the upper or lower boundary. The flow may be subcritical, critical or supercritical. These different states are identified in a pseudo-Froude-number plane analogous to that developed by Armi (1986) for non-rotating flows. If the ratio of the channel width to the Rossby radius is constant along the length of the channel, then the solution may be traced along the entire channel using a single diagram. Several examples of maximal and submaximal exchanges are considered. This graphical method of solution is contrasted with the functional approach of Dalziel (1988, 1990).The exchange flux is determined as a function of the channel geometry, the strength of rotation and the difference in Bernoulli potential between the two layers.
Development of a Method To Analyze Single Cell Activity by Using Dielectrophoretic Levitation
Authors: Hakoda M. , Hachisu T. , Wakizaka Y. , Mii S. , Kitajima N. 
Published: December 2005

AbstractIn cell fusion and genetic recombination, although the activity of single cells is extremely important, there is no method to analyze single cell activity. Development of a quick analyzing method for single cell activity is desired in various fields. Dielectrophoresis (DEP) refers to the force exerted on the induced dipole moment of an uncharged dielectric and/or conductive particle by a nonuniform electric field. By applying DEP, we obtained experimentally a relationship between the cell activity and the dielectric property, Re[K(ω)], and examined how to evaluate the single cell activity by measuring Re[K(ω)] of a single cell. A cone and plate electrode geometry was adapted in order to achieve the feedback‐controlled DEP levitation. The single cell is exposed to a nonuniform field induced by the cone and plate electrode, and a more polarizable cell is moved to the direction of the cone electrode by the DEP force. The cell settles in the position where the DEP force and gravity are balanced by controlling applied voltage. This settled position, measured on the center axis of the cone electrode, depended on the dielectric constant of the cell. From these results, the relationship between the specific growth rates in cell growth phase and the dielectric properties Re[K(ω)] was obtained. Furthermore, the effect on the cell activity of various stresses, such as concentration of carbon dioxide, temperature, etc., was examined.
Kinetics of the Extraction of Succinic Acid with Tri‐n‐octylamine in 1‐Octanol Solution
Authors: Jun Young‐Si , Huh Yun Suk , Hong Won Hi , Hong Yeon Ki 
Published: December 2005

AbstractKinetic studies for the extraction of succinic acid from aqueous solution with 1‐octanol solutions of tri‐n‐octylamine (TOA) were carried out using a stirred cell with a microporous hydrophobic membrane. The interfacial concentrations of species were correlated and thus the intrinsic kinetics was obtained. The overall extraction process was controlled by the chemical reaction at or near the interface between the aqueous and organic phases. The formation reaction of succinic acid‐TOA complex was found to be first order with respect to the concentration of succinic acid in the aqueous phase and the order of 0.5 with respect to that of TOA in the organic phase with a rate constant of (3.14 ± 0.6) × 10−8 m2.5·mol−0.5·s−1. The dissociation reaction of succinic acid‐TOA complex was found to be the second‐order with respect to that of succinic acid‐TOA complex in the organic phase and the order of –2 with respect to that of TOA in the organic phase with a rate constant of (1.44 ± 1.4) × 10−4 mol·m−2·s−1.
Real‐Time Monitoring of Recombinant Bacterial Proteins by Mass Spectrometry
Authors: Jones Jeffrey J. , Wilkins Charles L. , Cai Ying , Beitle Robert R. , Liyanage Rohanna , Lay Jackson O. 
Published: December 2005

AbstractGenetically altered bacteria manipulated to express green fluorescent protein (GFP) were used in an investigation of real‐time monitoring for recombinant protein expression in cell by matrix‐assisted laser desorption/ionization (MALDI) time‐of‐flight (TOF) mass spectrometry (MS). A significant advantage to whole cell MALDI MS is its ability to analyze bacterial cultures without pretreatment other than concentration. This paper describes the simultaneous analysis of overexpressed GFP recombinant Escherichia coliJM101 by MALDI‐TOF MS and standard fluorescence measurements. Cells were harvested from liquid culture media during a 12 h GFP induced expression cycle to demonstrate the feasibility of near real‐time monitoring of induced protein expression. The results show that although MALDI MS is not as sensitive as fluorescence measurements, expression levels of the targeted protein can easily be determined. Data available only through MALDI MS measurements reveal the presence of both native GFP and GFP‐(histidine)6 proteins. Additionally, biochemical processes not yet fully understood are observed in the presence and absence of ribosomal protein constituents. Thus, the work presented here demonstrates the ability of MALDI MS to monitor and characterize in real time the expression of targeted and unexpected genetically recombinant proteins in active cell cultures.
Free‐Standing Nanogold Membranes as Supports for the Growth of Calcium Phosphate Crystals
Authors: Rautaray Debabrata , Sastry Murali 
Published: December 2005

AbstractCurrent strategies for bone tissue regeneration focus on the development of implantable matrices that mimic biological tissues. Inorganic composites are of special interest for bone substitute applications. It is necessary to create an artificial three‐dimensional scaffold‐like porous material with certain geometrical structure to induce bone growth. We report here the growth of calcium phosphate crystals on free‐standing carboxylic acid functionalized gold nanoparticle membranes. The gold nanoparticle membrane is synthesized by the spontaneous reduction of aqueous chloroaurate ions by a diamine molecule at a liquid‐liquid interface. This membrane is robust and malleable, and most importantly, the gold nanoparticles in the membrane may be functionalized with suitable ligands. In this study, the amino acids aspartic acid and cysteine together with an aromatic bifunctional molecule, anthranilic acid, were used to modify the surface of the gold nanoparticles in the membrane. The free carboxylic acid groups on the gold nanoparticles further to functionalization with these molecules were then used to bind Ca2+ ions and reacted with phosphate ions to yield calcium phosphate. The nature of the nanogold surface modifier directed the formation of either crystalline hydroxyapatite or amorphous calcium phosphate. The nanogold membrane thus suggests potential biomedical application as biocompatible implants and grafts.
Continuous Adsorption and Recovery of Cr(VI) in Different Types of Reactors
Authors: Bai Sudha R. , Abraham T. Emilia 
Published: December 2005

AbstractThis study reports the results of experiments on continuous adsorption and desorption of Cr(VI) ions by a chemically modified and polysulfone‐immobilized biomass of the fungus Rhizopus nigricans. A fixed quantity of polymer‐entrapped biomass beads corresponding to 2 g of dry biomass powder was employed in packed bed, fluidized bed, and stirred tank reactor for monitoring the continuous removal and recovery of Cr(VI) ions from aqueous solution and synthetic chrome plating effluent. Parameters such as flow rate (5, 10 and 15 mL/min), inlet concentration of Cr(VI) ions (50, 100, 150 and 250 mg/L) and the depth of biosorbent packing (22.8, 11.2 and 4.9 cm) were evaluated for the packed bed reactor. The breakthrough time and the adsorption rates in the packed bed column were found to decrease with increasing flow rate and higher Cr inlet concentrations and to increase with higher depths of sorbent packing. To have a comparative analysis of Cr adsorption efficiency in different types of reactors, the fluidized bed reactor and stirred tank reactor were operated using the same quantities of biosorbent material. For the fluidized bed reactor, Cr(VI) solution of 100 mg/L was pumped at 5 mL/min and fluidized by compressed air at a flow rate of 0.5 kg/cm.2 The stirred tank reactor had a working volume of 200 mL capacity and the inlet/outlet flow rate was 5 mL/min. The maximum removal efficiency (mg Cr/g biomass) was obtained for the stirred tank reactor (159.26), followed by the fluidized reactor (153.04) and packed bed reactor (123.33). In comparison to the adsorption rate from pure chromate solution, approximately 16% reduction was monitored for synthetic chrome plating effluent in the packed bed. Continuous desorption of bound Cr ions from the reactors was effective with 0.01 N Na2CO3 and nearly 80–94% recoveries have been obtained for all the reactors.
Quick Selection of a Chimeric T2 Phage That Displays Active Enzyme on the Viral Capsid
Authors: Tanji Yasunori , Murofushi Keita , Miyanaga Kazuhiko 
Published: December 2005

AbstractWe designed a bacteriophage T2 system to display proteins fused at the N‐terminus of the head protein small outer capsid (SOC) of a T2 phage. To facilitate selection of chimeric phage, a T2 phage encoding the β‐galactosidase gene (βgal) upstream of the soc gene was constructed. The phage, named T2βGal, produces blue plaques on agar plates containing XGal. Subsequently, a plasmid encoding the target protein upstream of soc was constructed and used to transform E. coli BE cells. Transformed cells were infected with T2βGal and homologous recombination between phage DNA and the plasmid resulted in a chimeric phage that produced transparent plaques due to the excision of the βgal gene. Chitosanase of Bacillus sp. strain K17 (ChoK), consisting of 453 amino acids, was used as a model target protein. Recombinant T2 phage that produced ChoK was named T2ChoK. T2ChoK was produced from T2βGal at a recombination frequency of about 0.1%. On the other hand, the value for T2βGal produced from wild‐type T2 was 0.001 %. This new system enables us to select recombinant phage very quickly and accurately. The number of molecules of ChoK was calculated at 14.7 per single phage. Latent period and burst size were estimated for the chimeric phages.
Variable Site‐Occupancy Classification of N‐Linked Glycosylation Using Artificial Neural Networks
Authors: Senger Ryan S. , Karim M. Nazmul 
Published: December 2005

AbstractA novel neural‐network‐based model has been developed for the prediction of N‐linked glycosylation characteristics related to glycosylation site‐occupancy. Intracellular oligosaccharide transfer to a polypeptide is known to be either robust or dependent upon culture conditions during pharmaceutical production. This glycan attachment is classified by the model as robust or variable and is based on an input of the polypeptide primary sequence around the site of glycosylation. The glycosylation model utilizes multiple recurrent neural networks followed by a perceptron classifier. The input length of the polypeptide chain around the site of glycosylation (glycosylation window) was optimized through multiple independent training sessions. Incorporation of five residues prior (n – 5) to the site of glycosylation (n) and four residues beyond (n + 4) the glycan attachment site led to optimal network performance. The size of the glycosylation window for site‐occupancy determination is much larger than has been previously reported. This model was developed to evaluate the effects of theoretical polypeptide mutations on glycosylation site‐occupancy characteristics. Following correct prediction of the model testing data set, 20 independent networks were used to predict site‐occupancy characteristics of wild‐type and mutants of the rabies virus glycoprotein (rgp). Simulation results strongly correlated with previously published experimental results (Kasturi, L.; Hegang, C.; Shakin‐Eshleman, S. H. Regulation of N‐linked core glycosylation: use of a site‐directed mutagenesis approach to identify Asn‐Xaa‐Ser/Thr sequons that are poor oligosacchride acceptors. Biochem. J.1997, 323, 415–419. Mellquist, J. L.; Kasturi, L.; Spitalnik, S. L.; Shakin‐Eshleman, S. H. The amino acid following an Asn‐X‐Ser/Thr sequon is an important determinant of N‐linked core glycosylation efficiency. Biochemistry 1998, 37, 6833–6837). Further simulations on purely theoretical sequences suggested that influences of charged residues were a subset of multiple mechanisms in the determination of glycosylation site‐occupancy.
Molecular Characterization of Anaerobic Microbial Communities from Benzene‐Degrading Sediments under Methanogenic Conditions
Authors: Chang Wook , Um Youngsoon , Holoman Tracey R. Pulliam 
Published: December 2005

AbstractAnaerobic benzene degradation was confirmed in microbial communities enriched from Baltimore Harbor (Baltimore, MD) sediments under methanogenic conditions. Molecular characterization based on 16S rDNA gene sequences revealed that the strains in the communities were diversely affiliated with such phylogenetic branches as the Bacteroidetes, Euryarchaeota, Firmicutes, and Thermotogaephyla. Of interest was that the majority of the microbial populations detected in these cultures were closely related to the members of dechlorinating microbial communities. Further, some of those species were previously found in naphthalene‐ or phenanthrene‐degrading methanogenic communities. Finally, this result could be used to design targeted isolation strategies for anaerobic benzene‐degrading strains under methanogenic conditions.
Bioengineering of a Cellulosic Fabric for Insecticide Delivery via Grafted Cyclodextrin
Authors: Romi Roberto , Nostro Pierandrea Lo , Bocci Eugenio , Ridi Francesca , Baglioni Piero 
Published: December 2005

Abstractβ‐Cyclodextrin (β‐CD) can be easily grafted onto cellulosic textiles through covalent bonds. In such a way β‐CD empty cavities provide an efficient tool for entrapping different kinds of hydrophobic molecules on the surface of the fabric and releasing them slowly in time. The capability of cyclodextrins to include hydrophobic molecules such as fragrances, antimicrobial agents, and other chemicals can be then exploited to produce new grafted textiles with peculiar and useful performances. In this work we report the inclusion of two different products, the pyrethroid insecticide permethrin (PERM) and the insect repellentN,N‐diethyl‐m‐toluamide (DEET), into β‐CD molecules grafted on cotton fabric. UV‐vis spectrophotometry and thermal analysis confirmed the presence of the guest molecules on the fabric surface. Bioassays were carried out on two mosquito species of medical importance,Aedes aegyptiandAnopheles stephensi; knock down effect and mortality were measured using standard World Health Organization (WHO) cone tests. Repellency and irritancy (blood feeding inhibition) were also measured using cage tests and a baited tunnel device. PERM‐treated fabrics kept the insecticidal/irritant efficacy even for a long time after the treatment, whereas DEET activity lasted more shortly.
Identification of glucoselysine-6-phosphate deglycase, an enzyme involved in the metabolism of the fructation product glucoselysine
Authors: Wiame Elsa , Lamosa Pedro , Santos Helena , Van Schaftingen Emile 
Published: December 2005

The metabolism of the glycation product fructose-ϵ-lysine in Escherichia coli involves its ATP-dependent phosphorylation by a specific kinase (FrlD), followed by the conversion of fructoselysine 6-phosphate into glucose 6-phosphate and lysine by fructoselysine-6-phosphate deglycase (FrlB), which is distantly related to the isomerase domain of glucosamine-6-phosphate synthase. As shown in the present work, several bacterial operons comprise: (1) a homologue of fructoselysine-6-phosphate deglycase; (2) a second homologue of the isomerase domain of glucosamine-6-phosphate synthase, more closely related to it; and (3) components of a novel phosphotransferase system, but no FrlD homologue. The FrlB homologue (GfrF) and the closer glucosamine-6-phosphate synthase homologue (GfrE) encoded by an Enterococcus faecium operon were expressed in E. coli and purified. Similar to FrlB, GfrF catalysed the reversible conversion of fructoselysine 6-phosphate into glucose 6-phosphate and lysine. When incubated with fructose 6-phosphate and elevated concentrations of lysine, GfrE catalysed the formation of a compound identified as 2-ϵ-lysino-2-deoxy-6-phospho-glucose (glucoselysine 6-phosphate) by NMR. GfrE also catalysed the reciprocal conversion, i.e. the formation of fructose 6-phosphate (but not glucose 6-phosphate) from glucoselysine 6-phosphate. The equilibrium constant of this reaction (0.8 M) suggests that the enzyme serves to degrade glucoselysine 6-phosphate. In conclusion, GfrF and GfrE serve to metabolize glycation products formed from lysine and glucose (fructoselysine) or fructose (glucoselysine), via their 6-phospho derivatives. The latter are presumably formed by the putative phosphotransferase system encoded by gfrA–gfrD. The designation gfr (glycation and fructation product degradation) is proposed for this operon. This is the first description of an enzyme participating in the metabolism of fructation products.
A novel regulation of IRS1 (insulin receptor substrate-1) expression following short term insulin administration
Authors: Ruiz-Alcaraz Antonio J. , Liu Hui-Kang , Cuthbertson Daniel J. , Mcmanus Edward J. , Akhtar Simeen , Lipina Christopher , Morris Andrew D. , Petrie John R. , Hundal Hari S. , Sutherland Calum 
Published: December 2005

Reduced insulin-mediated glucose transport in skeletal muscle is a hallmark of the pathophysiology of T2DM (Type II diabetes mellitus). Impaired intracellular insulin signalling is implicated as a key underlying mechanism. Attention has focused on early signalling events such as defective tyrosine phosphorylation of IRS1 (insulin receptor substrate-1), a major target for the insulin receptor tyrosine kinase. This is required for normal induction of signalling pathways key to many of the metabolic actions of insulin. Conversely, increased serine/threonine phosphorylation of IRS1 following prolonged insulin exposure (or in obesity) reduces signalling capacity, partly by stimulating IRS1 degradation. We now show that IRS1 levels in human muscle are actually increased 3-fold following 1 h of hyperinsulinaemic euglycaemia. Similarly, transient induction of IRS1 (3-fold) in the liver or muscle of rodents occurs following feeding or insulin injection respectively. The induction by insulin is also observed in cell culture systems, although to a lesser degree, and is not due to reduced proteasomal targeting, increased protein synthesis or gene transcription. Elucidation of the mechanism by which insulin promotes IRS1 stability will permit characterization of the importance of this novel signalling event in insulin regulation of liver and muscle function. Impairment of this process would reduce IRS1 signalling capacity, thereby contributing to the development of hyperinsulinaemia/insulin resistance prior to the appearance of T2DM.
Activation and torque deficits in ACL‐reconstructed patients 4 months post‐operative
Authors: Nicol Caroline , Gouby Nicolas , Coudreuse Jean‐marie , Flin Christian , Viton Jean‐michel , Delarque Alain , Brunet Christian , Komi Paavo 
Published: December 2005

This study compares knee extension and flexion torques and electromyographic (EMG) activity of normal and anterior cruciate ligament (ACL)‐reconstructed knees during maximal unilateral isometric and isokinetic tests performed 4–5 months after ACL reconstruction. The subjects consisted of 3 age‐ and activity‐matched groups of 6 subjects: a healthy control group (Ctrl) and 2 groups of patients, with Kenneth‐Jones technique using autologous patellar‐ligament graft (KJ group) and autologous graft from the semitendinosus tendon (ST group). When compared to the Ctrl group values, each patient group had significant bilateral extension torque deficits in isometric and at slow velocity concentric conditions. In the Op leg, this deficit was associated with lower quadriceps EMG activation. In all tests, bilateral hamstring co‐activation level was lower in the patient groups. Flexion torque deficits were observed in the Op leg of both patient groups and in the Nop leg of the KJ group, with minor differences in either hamstring EMG activation or quadriceps co‐activation. The inter‐leg difference in extension and flexion torques were significant for both patient groups, but only in the isometric strength test, and with no difference in activation. These data demonstrate bilateral knee extension and flexion torque deficits a few months after ACL reconstruction. The observed deficit in quadriceps activation emphasizes the interest to perform combined EMG and strength testings quite early during the rehabilitation period.