bluuebunny/crossref_metadata_2025_split huggingface dataset:
The thioredoxin system from Streptomyces coelicolor
Authors: Štefanková Petra , Perečko Dušan , Barák Imrich , Kollárová Marta 
Published: February 2006

AbstractThis paper describes the cloning, purification and characterization of thioredoxin (TrxA) and thioredoxin reductase (TrxR) from bacterial strain Streptomyces coelicolor . The genes of S. coelicolor encoding TrxA and TrxR were amplified by polymerase chain reaction, inserted into pET expression vector and used to overexpress these proteins in Escherichia coli . TrxA and TrxR were produced as the hexahistidine fusion proteins and were recovered from the cytoplasm as the soluble proteins. The activity of the purified recombinant proteins was demonstrated. The activity of TrxA was shown by efficient reduction of insulin and activity of NADPH‐dependent TrxR was revealed by catalyses of 5,5′‐dithiobis (2‐nitrobenzoic acid) (DTNB) reduction reaction. The reduction reaction was fully dependent upon the presence of TrxA as intermediate electron carrier with the pH optimum 7.5 and the temperature optimum 29 °C. Km value of TrxR for TrxA was 0.217 ± 0.02 µM. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of nif genes in N2‐fixing bacterial strains isolated from rice fields along the Yangtze River Plain
Authors: Xie Guang Hui , Cui Zongjun , Yu Jun , Yan Jing , Hai Weili , Steinberger Yosef 
Published: February 2006

AbstractThe aim of this research was to identify nifH and nifHDKYE ′ genes in twenty strains of N2‐fixing heterotrophic bacteria isolated from rice fields in the Yangtze River Plain. Southern hybridization of the total DNA from each strain was performed with the Klebsiella pneumoniae nifHDKYE ′ gene probe (6.2 kb Eco RI fragment from pSA30) and the Azospirillum brasilense nifH gene probe (0.6 kb Eco RI‐Hin dIII fragment from pHU8). We found that Eco RI fragments of total DNA from Aeromonas hydrophila HY2, Bacillus azotoformans FD, Bacillus licheniformis NCH1, NCH5, WH4, Bacillus brevis NC2, Bacillus pumilus NC12, Bacillus cereus NCH2, Citrobacter freundii HY5, HY9, Derxia gummosa HZ5, Pseudomonas mendocina HZ1 and Pseudomonas pseudoalcaligenes WH3 were positively hybridized with both of the probes. Agrobacterium radiobacter HY17, Corynebacterium sp. HY12, YZ and Pseudomonas sp. HY11 had Eco RI fragments hybridized with the K. pneumoniae nifHDKYE ′ gene probe. An Eco RI fragment of total DNA from Bacillus megaterium YY4 was positively hybridized to the A. brasilense nifH gene probe. No hybridization sign was found in the total DNA fragments from Alcaligenes cupidus YY6 and Corynebacterium sp. NC11 hybridized with either of the gene probes. The data provide the number and size of EcoRI fragments of the total DNA hybridized with the nif gene probes for these strains of rarely studied species, suggesting additional evidence for N2 fixing and nif gene diversity of N2‐fixing bacteria in rice fields along the Yangtze River Plain. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biodegradation of gallotannins and ellagitannins
Authors: Mingshu Li , Kai Yao , Qiang He , Dongying Jia 
Published: February 2006

AbstractNowadays, many researches have been made on gallotannin biodegradation and have gained great success in further utilization. Some of industrial applications of these findings are in the production of tannase, the biotransformation of tannic acid to gallic acid or pyrogallol and detannification of food and fodder. Although ellagitannins have the typical C–C bound which is more difficult to be degraded than gallotannins, concerted efforts are still in progress to improve ellagitannin degradation and utilization. Currently, more attention is mainly focused on intestinal microflora biodegradation of tannins especially ellagitannins which can contribute to the definition of their bioavailability for both human beings and ruminants. Also there have been endeavours to utilize the tannin‐degrading activity of different fungi for ellagitannin‐rich biomass, which will facilitate application of tannin‐degrading enzymes in strategies for improving industrial and livestock production. Due to the complicated structures of complex tannins and condensed tannins, the biodegradation of them is much more difficult and there are fewer researches on them. Therefore, the researches on the mechanisms of gallotannin and ellagitannin biodegradation can result in the overall understanding to the biodegradation of complex tannins and condensed tannins. Biodegradation of tannins is in an incipient stage and further studies have to be carried out to exploit the potential of various tannins for largescale applications in food, fodder, medicine and tannery effluent treatment. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adsorptive removal of textile dyes from aqueous solutions by dead fungal biomass
Authors: Asma Dilek , Kahraman Sibel , Cing Seval , Yesilada Ozfer 
Published: February 2006

AbstractDead fungal biomass prepared from Phanerochaete chrysosporium and Funalia trogii was tested for their efficiency in removal of textile dyes. The effects of contact time, initial dye concentration, amount of dead biomass and agitation rate on dye removal have been determined. Removal of all dyes required a very short time (60 min). Experimental results show that, P. chrysosporium was more effective than F. trogii . An increase in the amount of dead biomass positively affected of the dye removal. The removal efficiency of different amount of biomass was in order 1 g > 0.5 g > 0.2 g > 0.1 g. The highest removal was obtained at 150–200 rpm. Slightly lower removing activities were found at lower agitation rates. This study showed that it was possible to remove textile dyes by dead biomass of P. chrysosporium . (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Short‐term microvascular response of striated muscle to cp‐Ti, Ti‐6Al‐4V, and Ti‐6Al‐7Nb
Authors: Pennekamp Peter H. , Gessmann Jan , Diedrich Oliver , Burian Björn , Wimmer Markus A. , Frauchiger Vinzenz M. , Kraft Clayton N. 
Published: February 2006

AbstractDue to excellent mechanical properties and good corrosion resistance, titanium–aluminium–vanadium (Ti‐6Al‐4V) and titanium–aluminium–niobium (Ti‐6Al‐7Nb) are extensively used for orthopedic surgery. Concern has been voiced concerning the implications of the constituent vanadium in Ti‐6Al‐4V on the surrounding environment. Particularly in osteosynthesis where the alloys stand in direct contact to skeletal muscle, undesirable biologic reactions may have severe consequences. In a comparative study, we assessed in vivo nutritive perfusion and leukocytic response of striated muscle to the metals Ti‐6Al‐4V, Ti‐6Al‐7Nb, and commercially pure titanium (cpTi), thereby drawing conclusions on their short‐term inflammatory potential. In 28 hamsters, utilizing the dorsal skinfold chamber preparation and intravital microscopy, we quantified primary and secondary leukocyte–endothelial cell interaction, leukocyte extravasation, microvascular diameter change, and capillary perfusion in collecting and postcapillary venules of skeletal muscle. A manifest discrepancy between the metals concerning impact on local microvascular parameters was not found. All metals induced an only transient and moderate inflammatory response. Only a slight increase in leukocyte recruitment and a more sluggish recuperation of inflammatory parameters in animals treated with Ti‐6Al‐4V compared to the other two metals suggested a minor, overall not significant discrepancy in biocompatibility. Gross toxicity of bulk Ti‐6Al‐4V on surrounding tissue could not be found. Conclusively, the commonly used biomaterials Ti‐6Al‐4V, Ti‐6Al‐7Nb, and cpTi induce an only transient inflammatory answer of the skeletal muscle microvascular system. Our results indicate that on the microvascular level the tested bulk Ti‐alloys and cpTi do not cause adverse biologic reactions in striated muscle. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:531–540, 2006
Shoulder joint position sense improves with elevation angle in a novel, unconstrained task
Authors: Suprak David N. , Osternig Louis R. , van Donkelaar Paul , Karduna Andrew R. 
Published: February 2006

AbstractProprioception, encompassing the submodalities of kinesthesia and joint position sense, is important in the maintenance of joint stability, especially in the shoulder. The purpose of this study was to examine the effects of plane and elevation angle on unconstrained shoulder joint position sense. Twenty‐two subjects (12 male, 10 female) without a history of shoulder pathology were recruited from a university campus. Subjects attempted to replicate, with respect to plane and elevation angles, various target positions. Target positions consisted of five plane angles at 90° of arm elevation and five arm elevation angles in the scapular plane. All target positions were tested twice to assess the reliability of the measurement. Intraclass correlation coefficients were generally low across target positions, possibly owing to the novelty and demanding nature of the task. No differences in repositioning errors were observed between plane angles (p = 0.255). Repositioning errors decreased linearly as the elevation angle increased from 30° to 90° (p = 0.007) and increased again from 90° to 110° of elevation (p = 0.029). Our results suggest that unconstrained joint position sense may be enhanced with increased muscular activation levels. Further, afferent feedback from musculotendinous mechanoreceptors may dominate over that from capsuloligamentous sources in unconstrained movements. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:559–568, 2006
Hermann Staudinger Award 2006
Authors: Mülhaupt Rolf 
Published: February 2006

AbstractMacromolecular News: This section contains news of the macromolecular community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. The editorial office decides which articles will be published.
On the Nitroxide Quasi‐Equilibrium in the Alkoxyamine‐Mediated Radical Polymerization of Styrene
Authors: Saldívar‐Guerra Enrique , Bonilla José , Becerril Fabiola , Zacahua Gregorio , Albores‐Velasco Martha , Alexander‐Katz Roberto , Flores‐Santos Leticia , Alexandrova Larissa 
Published: February 2006

AbstractSummary: The range of validity of two popular versions of the nitroxide quasi‐equilibrium (NQE) approximation used in the theory of kinetics of alkoxyamine mediated styrene polymerization, are systematically tested by simulation comparing the approximate and exact solutions of the equations describing the system. The validity of the different versions of the NQE approximation is analyzed in terms of the relative magnitude of (dN/dt)/(dP/dt). The approximation with a rigorous NQE, kc[P][N] = kd[PN], where P, N and PN are living, nitroxide radicals and dormant species respectively, with kinetic constants kc and kd, is found valid only for small values of the equilibrium constant K (10−11–10−12 mol · L−1) and its validity is found to depend strongly of the value of K. On the other hand, the relaxed NQE approximation of Fischer and Fukuda, kc[P][N] = kd[PN]0 was found to be remarkably good up to values of K around 10−8 mol · L−1. This upper bound is numerically found to be 2–3 orders of magnitude smaller than the theoretical one given by Fischer. The relaxed NQE is a better one due to the fact that it never completely neglects dN/dt. It is found that the difference between these approximations lies essentially in the number of significant figures taken for the approximation; still this subtle difference results in dramatic changes in the predicted course of the reaction. Some results confirm previous findings, but a deeper understanding of the physico‐chemical phenomena and their mathematical representation and another viewpoint of the theory is offered. Additionally, experiments and simulations indicate that polymerization rate data alone are not reliable to estimate the value of K, as recently suggested.Validity of the rigorous nitroxide quasi‐equilibrium assumption as a function of the nitroxide equilibrium constant.imageValidity of the rigorous nitroxide quasi‐equilibrium assumption as a function of the nitroxide equilibrium constant.
Modeling the Effect of Oxygen on Photopolymerization Kinetics
Authors: O'Brien Allison K. , Bowman Christopher N. 
Published: February 2006

AbstractSummary: A comprehensive one‐dimensional photopolymerization model was utilized to investigate the effect of oxygen on the free‐radical photopolymerization kinetics. The spatial profiling aspect of the model provided insight into the heterogeneity of the cure kinetics due to oxygen inhibition, specifically the variance in the concentration profile of monomer and oxygen. Double bond conversion was negligible for the top ten microns of the film due to continuous oxygen diffusion, and increased with increasing depth. Similarly, the oxygen concentration decreased with increasing depth due to the competition between oxygen diffusion time and the polymerization rate. The effect of initiation rate on the extent of oxygen inhibition was investigated for various oxygen concentrations. As the initiation rate increased, the polymerization rate increased, and eventually approached that of a sample in an inert environment. Similarly, as the oxygen concentration was decreased, the polymerization rate increased. The effect of varying the initiation rate on the cure profile in the oxygen‐exposed film was also studied. It was found that the unpolymerized tacky layer decreased from 50 µm to 5 µm with a 3 order of magnitude increase in initiation rate. Using the pseudo steady state approximation, the relationship between polymerization rate and initiation rate was derived for films in an oxygen environment. A direct relationship between the polymerization and initiation rate was found for films in air. The polymerization model supported this derivation and found that as the oxygen concentration was decreased, the dependence on initiation rate, or alpha, decreased, reaching the accepted value of 0.5 for alpha in inert environments.Double bond conversion versus film depth and cure time.imageDouble bond conversion versus film depth and cure time.
Mesoscopic Morphology of Proton‐Conducting Polyelectrolyte Membranes of Nafion® Type: A Self‐Consistent Mean Field Simulation
Authors: Galperin Dmitry Y. , Khokhlov Alexei R. 
Published: February 2006

AbstractSummary: A SCMF simulation is presented for a coarse‐grained model of Nafion®. Based on a number of simplifying assumptions, this study predicts distinct morphological changes in the material upon alteration of temperature and water content. We found that the hydration level corresponding to the microphase segregation depends on the temperature of the system. Spherical clusters constituting the hydrophilic microphase of the membrane at relatively low water content (but above the transition point) grow in size, coalesce and form a network of channels responsible for the ionic transport at higher hydration levels. This hydrophilic phase is shielded from the hydrophobic matrix by the sidechains of Nafion®, their end‐groups being turned towards the water clusters. The results obtained are similar to those reported from dissipative particle dynamics studies and support the “cluster‐network” model for the low hydration levels and the “sponge” model at higher hydration levels. The simulation approach chosen proved to be effective for the mesoscopic structure analysis of the heterogeneous polymeric material.Schematic representation of the structure of Nafion®‐water blends.imageSchematic representation of the structure of Nafion®‐water blends.
Botulinum toxin changes intrafusal feedback in dystonia: A study with the tonic vibration reflex
Authors: Trompetto Carlo , Currà Antonio , Buccolieri Alessandro , Suppa Antonello , Abbruzzese Giovanni , Berardelli Alfredo 
Published: February 2006

AbstractTo investigate the possible role of botulinum toxin (BT‐A) injection in reducing muscle afferent feedback, we evaluated electrophysiologically 10 right‐handed patients with writer's cramp before and 3 weeks after treatment. The ratio between pre‐ and postinjection values of maximal M‐wave (M‐max), maximal voluntary contraction (MVC), and tonic vibration reflex (TVR) were measured in the injected muscles (wrist flexors or extensors). In all the subjects, BT‐A injection reduced the TVR more than the M‐max and MVC (mean ratio ± SD: TVR, 0.24 ± 0.22; MVC, 0.59 ± 0.32; M‐max, 0.68 ± 0.24; P = 0.003). Long‐term evaluation of 2 patients disclosed that, after 7 months, when some clinical benefits persisted, M‐max and MVC had fully recovered, whereas the TVR was still depressed. This special sensitivity of the TVR to suppression by BT‐A injection could be mediated by the chemodenervation of intrafusal muscle fibers, leading to a reduction in spindle inflow to the central nervous system during vibration. The action on intrafusal fibers could alter sensorimotor integration, thus contributing to the clinical benefits of BT‐A injection. © 2006 Movement Disorder Society
Feasibility of simultaneous temperature and tissue stiffness detection by MRE
Authors: Le Yuan , Glaser Kevin , Rouviere Olivier , Ehman Richard , Felmlee Joel P. 
Published: February 2006

AbstractTemperature and tissue stiffness are two indices that can be used to monitor MRI‐guided focused ultrasound thermal therapy. It would be beneficial to have both measures available to monitor treatment progression during thermal therapy. MR Elastography (MRE) has already been shown to provide tissue stiffness information; the purpose of this work is to demonstrate how temperature can be derived from the same MRE data acquisition. MRE data were acquired from 1.5% agarose phantoms and ex vivo porcine muscle tissue (from a grocery store) while they were heated slowly. The temperatures were measured using a fluorescent thermometer. The phase average from the MRE acquisition was used to calculate the phase shift induced by the proton resonance frequency shift associated with the temperature change. The results show that the phase shift due to temperature extracted from MRE data correlate well with the temperature change recorded by thermometer, yielding a temperature coefficient of −0.0096 ppm/°C for the agarose phantom, and −0.0103 ppm/°C for the ex vivo porcine tissue. These results indicate that it is possible to simultaneously measure both temperature and tissue shear stiffness using a new method of MRE data reconstruction. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Measurement of arterial input functions for dynamic susceptibility contrast magnetic resonance imaging using echoplanar images: Comparison of physical simulations with in vivo results
Authors: Duhamel Guillaume , Schlaug Gottfried , Alsop David C. 
Published: February 2006

AbstractMeasurement of the arterial input bolus shape is essential to the quantification of mean transit time and blood flow with dynamic susceptibility contrast (DSC) MRI. Input functions derived from the echoplanar signal intensity within or near arteries are highly nonlinear, yet such input functions are widely used. We employed a physical model for the echoplanar signal intensity from an artery as a function of contrast agent concentration, artery size, and angle to the magnetic field to test approaches for the measurement of the arterial input function. The simulated results confirmed the strong nonlinearity of signal in the neighborhood of vessels. Of the input function measurement methods considered, the simulations suggested that measurement of signal near but not within a large vessel is most accurate, but mean transit times (MTT) calculated with these input functions are highly sensitive to peak bolus concentration. Input functions determined from voxels demonstrating the shortest first moment overestimated the MTT but the measured MTTs were more robust to changes in peak concentration. Characteristics of the measured in vivo input functions were consistent with the simulations. Our results emphasize the important contribution of input function errors to the uncertainty in MTT and blood flow imaging with DSC MRI. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
In vivo proton electron double resonance imaging of the distribution and clearance of nitroxide radicals in mice
Authors: Li Haihong , He Guanglong , Deng Yuanmu , Kuppusamy Periannan , Zweier Jay L. 
Published: February 2006

AbstractProton electron double resonance imaging (PEDRI) is an emerging technique that utilizes the Overhauser effect to enable in vivo and in vitro imaging of free radicals in biological systems. Nitroxide spin probes enable measurement of tissue redox state based on their reduction to diamagnetic hydroxylamines. PEDRI instrumentation at 0.02 T was applied to assess the ability to image the in vivo distribution, clearance, and metabolism of nitroxide radicals in living mice. Using phantoms of 2,2,5,5‐tetramethyl‐3‐carboxylpyrrolidine‐N‐oxyl (PCA) in normal saline the dependence of the enhancement on RF power and spin probe concentration was determined. Enhancements of up to −23 were obtained in phantoms with 2 mM levels. Maximum enhancement of −7 was observed in vivo. Coronal images of nitroxide‐infused mice enabled visualization of the kinetics of spin probe uptake and clearance in different organs including the great vessels, heart, lungs, kidneys, and bladder with an in‐plane spatial resolution of 0.6 mm. PEDRI of living mice was also performed using 3‐carbamoyl‐proxyl and 2,2,6,6‐tetramethyl‐4‐oxopiperidine‐N‐oxyl to compare the different rate of clearance and metabolism among different nitroxide probes. PCA, due to its intravascular compartmentalization, provided the sharpest contrast for the vascular system and highest enhancement values in the PEDRI images among the three nitroxides. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Robust analysis of short echo time 1H MRSI of human brain
Authors: Zhu X. P. , Young K. , Ebel A. , Soher B. J. , Kaiser L. , Matson G. , Weiner W. M. , Schuff N. 
Published: February 2006

AbstractShort echo time proton MR Spectroscopic Imaging (MRSI) suffers from low signal‐to‐noise ratio (SNR), limiting accuracy to estimate metabolite intensities. A method to coherently sum spectra in a region of interest of the human brain by appropriate peak alignment was developed to yield a mean spectrum with increased SNR. Furthermore, principal component (PC) spectra were calculated to estimate the variance of the mean spectrum. The mean or alternatively the first PC (PC1) spectrum from the same region can be used for quantitation of peak areas of metabolites in the human brain at increased SNR. Monte Carlo simulations showed that both mean and PC1 spectra were more accurate in estimating regional metabolite concentrations than solutions that regress individual spectra against the tissue compositions of MRSI voxels. Back‐to‐back MRSI studies on 10 healthy volunteers showed that mean spectra markedly improved reliability of brain metabolite measurements, most notably for myo‐inositol, as compared to regression methods. Magn Reson Med, 2006. Published 2006 Wiley‐Liss, Inc.