bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategies towards the Functionalization of Subtilisin E from Bacillus subtilis for Wool Finishing Applications
Authors: Araújo R. , Cavaco‐Paulo A. , Casal M. 
Published: July 2008

AbstractSubtilisin E is an alkaline serine protease secreted by the Gram positive bacterium Bacillus subtilis and widely used in industry as a biocatalyst for various processes. The most common application of subtilisins is in laundry detergents. However, due to environmental concerns, the application of subtilisins to treat wool, is under study. There are some reports regarding the attempts to substitute the conventional chlorine treatment by an enzymatic process capable of providing the same characteristics to the fabric, like anti‐shrinking and better uptake and fixation of the dyestuff. However, the degree of uncontrolled hydrolysis due to diffusion of the enzyme inside the wool fiber causes unacceptable losses of strength. To overcome this fact, and taking advantage of the x‐ray crystallographic structure, the authors have modified subtilisin E genetically, increasing its molecular weight, to restrict the hydrolysis to the surface of the wool fibers. Therefore, three genetically modified enzymes with a molecular weight 2‐fold to 4‐fold higher than the native subtilisin E were produced and assessed for activity. The prokaryotic expression systems, pET25b (+), pET11b and pBAD C, were explored for the production of recombinant enzymes. The results demonstrated that regardless the expression system or strain used, chimeric subtilisins were not expressed with the correct folding. No active and soluble recombinant protein was recovered under the testing conditions. Despite this drawback, a novel approach was described to increase the molecular weight of subtilisin. The reported results are noteworthy and can indicate good guidelines for future work aiming at the solubilization of recombinant chimeric subtilisins.
Comparative Analysis of the Physiological and Structural Properties of a Medium Chain Length Polyhydroxyalkanoate Depolymerase from Pseudomonas putida KT2442
Authors: de Eugenio L. I. , García J. L. , García P. , Prieto M. A. , Sanz J. M. 
Published: July 2008

AbstractMedium‐chain‐length polyhydroxyalkanoates (mcl‐PHAs) produced by Pseudomonas putida KT2442 can be chiral 3‐hydroxyalkanoic acids catabolized by the intracellular PhaZ depolymerase when the bacteria are cultured under carbon limitation. PhaZ is an intracellular depolymerase and is attached to PHA granules. In this study, the PhaZ expression was analyzed by Western blot and Real Time RT‐PCR assays. The PhaZ expression depends on the carbon source and nitrogen limitation conditions. The substrate recognition of the binding surface was altered using directed mutagenesis experiments. A structural comparison between intracellular and extracellular PHA depolymerases was carried out using PhaZ from P. putida KT2442 and P. fluorescens GK13, respectively. Both share the presence of a core displaying an α/β‐hydrolase fold, but the former would possess an additional “lid” domain that suggests some kind of interfacial activation and that may account for differences in substrate specificity for both proteins.
Development of Active Antimicrobial Fiber‐Based Chitosan Polysaccharide Nanostructures using Electrospinning
Authors: Torres‐Giner S. , Ocio M. J. , Lagaron J. M. 
Published: July 2008

AbstractThe electrospinning technology opens up enormous possibilities for the implementation of bio‐based materials and food hydrocolloids in numerous applications. In this context, chitosan is a sustainable, biocompatible, biodegradable, antimicrobial and non‐toxic polysaccharide of great relevance in many fields of application. Because of its abundance in nature and excellent biocompatibility, the cationic polysaccharide chitosan is a very promising polymer for producing functional nanofibers. Although the material has good physicochemical properties, the electrospinning of the polymer is far from easy. In the current study, the effect of an unprecedented number of parameters (including solvent nature, polymer origin, molecular weight and spinning conditions) on morphology is reported. The work also aims to ascertain the antimicrobial properties of the generated biofibers of chitosan and relate them to its chemical structure. Finally, a new route is provided to generate chitosan based nanoporous structures starting from blends of chitosan and polylactic acid.
Enzymatically‐Modified Melt‐Extruded Guides for Peripheral Nerve Repair
Authors: Chiono V. , Ciardelli G. , Vozzi G. , Cortez J. , Barbani N. , Gentile P. , Giusti P. 
Published: July 2008

AbstractIn this work, melt‐extruded guides for peripheral nerve repair were produced, based on blends between poly‐(ϵ‐caprolactone) and gelatin with a low gelatin amount (10 wt. %), with the aim of combining the good melt process ability of the synthetic polymer with the optimal biocompatibility of the natural polymer. In one case, a blend was produced between poly‐(ϵ‐caprolactone) and gelatin previously crosslinked by transglutaminase, using a solution mixing technique. The blend was then melt‐extruded obtaining nerve guidance channels. In another case, a blend between poly‐(ϵ‐caprolactone) and uncrosslinked gelatin was first produced, then melt‐extruded into tube‐shaped manufacts. Finally, poly‐L‐lysine was grafted on the gelatin domains exposed on the inner tube surface using transglutaminase catalysis, with the aim to confer to the channel guide a specific signaling for nerve cells attachment, proliferation and migration. Scanning electron microscopy (SEM) and Fourier transform infrared‐attenuated total reflectance spectroscopy (FTIR‐ATR) coupled with Chemical Imaging analysis showed that the obtained binary blends were poor compatible, however, appropriate mixing techniques might lead to an homogeneous distribution of gelatin domains within the poly‐(ϵ‐caprolactone) matrix. Confocal microscopy (CM) was applied as a powerful tool to study the accessibility of mTGase towards gelatin substrates, using suitable model lysine‐rich peptides (FITC‐labeled KKKKGY). Confocal microscopy also gave a confirmation of poly‐L‐lysine enzymatic grafting on the exposed gelatin domains on the inner blend tube surface. In vitro cell tests using S5Y5 neuroblastoma cells showed that the produced nerve guides were biocompatible, however, gelatin was confirmed to be a non‐specific protein for the attachment and proliferation of nerve cells. On the other hand, poly‐L‐lysine functionalization of the inner tube surface greatly improved the in‐vitro cell response.
A Novel Heme Peroxidase from Raphanus sativus Intrinsically Resistant to Hydrogen Peroxide
Authors: Gil‐Rodríguez P. , Ferreira‐Batista C. , Vázquez‐Duhalt R. , Valderrama B. 
Published: July 2008

AbstractAll known heme peroxidases are susceptible to self‐inflicted oxidative damage. Substrate oxidation in peroxidases is a naturally imperfect process and damage emerges from the utilization of protein elements as electron sources through the catalytic intermediate Compound III. Given their wide application potential, the search for more stable heme peroxidases has been actively pursued in the past, albeit with limited success. Here, the identification and biochemical characterization of a novel H2O2‐resistant isoenzyme is reported which was isolated from daikon radish (Raphanus sativus L. cv. daikon) and named Zo peroxidase (ZoPrx). Partial protein sequencing demonstrated that ZoPrx is more related to anionic isoenzyme 53 from Arabidopsis thaliana and to anionic isoenzyme 2 from Armoracia rusticana (HRPA2) than to any other protein known to date. The stability of ZoPrx was demonstrated by rigorous evaluation of resistance to H2O2 in the absence or presence of exogenous reductants which was consistent with porphyrin integrity. ZoPrx systematically outperformed the reference HRPA2 isoenzyme, a heme peroxidase known for its relative oxidative stability. The catalytic cycle of ZoPrx is conventional in the sense that the usual intermediate Compounds I and II were identified although reaction rates are significantly different compared to HRPA2. The distinctive characteristic of ZoPrx is that when Compound III is formed in the presence of excess H2O2, it is particularly more stable and, instead of engaging into the regular deactivation decay pathways, it commits to the ground state restoration decay pathway. ZoPrx is the only known case of a naturally occurring stable heme peroxidase based on intrinsic properties. Deeper study of the structural determinants underlying this property may eventually allow us to graft it into other peroxidases with established commercial potential.
Laccase‐Mediated Wood Surface Functionalization
Authors: Kudanga T. , Prasetyo E. N. , Sipilä J. , Nousiainen P. , Widsten P. , Kandelbauer A. , Nyanhongo G. S. , Guebitz G. 
Published: July 2008

AbstractLaccase‐catalyzed grafting of functional molecules on wood surface presents an eco‐friendly opportunity to improve wood properties. In a novel stepwise approach, functional molecules were bound to an enzymatically modified wood surface containing anchor groups. As anchor groups, phenolic amines were coupled to lignin moieties of wood using the 62 kDa Trametes hirsuta laccase. The coupling reaction to lignin was mimicked using the lignin model compounds 4‐O‐methyl guaiacylglycerol β‐guaiacyl ether A, guaiacylglycerol β‐guaiacyl ether E, dehydrodivanillyl alcohol type dibenzodioxocin D and syringylglycerol β‐guaiacylether G. Using this approach it was possible to increase binding of the fungicides propiconazole and thiabendazole by 42 % and 58 %, respectively, when compared to coupling onto wood pieces which were oxidized by laccase only.
Pharmacokinetics, dose‐range, and mutagenicity studies of methylphenidate hydrochloride in B6C3F1 mice
Authors: Manjanatha Mugimane G. , Shelton Sharon D. , Dobrovolsky Vasily N. , Shaddock Joseph G. , McGarrity Lynda G. , Doerge Daniel R. , Twaddle Nathan W. , Lin Chien‐Ju , Chen James J. , Mattison Donald R. , Morris Suzanne M. 
Published: July 2008

AbstractMethylphenidate hydrochloride (MPH) is one of the most frequently prescribed pediatric drugs for the treatment of attention deficit hyperactivity disorder. In a recent study, increased hepatic adenomas were observed in B6C3F1 mice treated with MPH in their diet. To evaluate the reactive metabolite, ritalinic acid (RA) of MPH and its mode of action in mice, we conducted extensive investigations on the pharmacokinetics (PK) and genotoxicity of the drug in B6C3F1 mice. For the PK study, male B6C3F1 mice were gavaged once with 3 mg/kg body weight (BW) of MPH and groups of mice were sacrificed at various time points (0.25–24 hr) for serum analysis of MPH and RA concentrations. Groups of male B6C3F1 mice were fed diets containing 0, 250, 500, 1,000, 2,000, or 4,000 ppm of MPH for 28 days to determine the appropriate doses for 24‐week transgenic mutation studies. Also, the micronucleus frequencies (MN‐RETs and MN‐NCEs), and the lymphocyte Hprt mutants were determined in peripheral blood and splenic lymphocytes, respectively. Mice fed 4,000 ppm of MPH lost significant BW compared to control mice (P < 0.01). There was a significant increase in the average liver weights whereas kidneys, seminal vesicle, testes, thymus, and urinary bladder weights of mice fed higher doses of MPH were significantly lower than the control group (P ≤ 0.05). There was no significant increase in either the Hprt mutant frequency or the micronucleus frequency in the treated animals. These results indicated that although MPH induced liver hypertrophy in mice, no genotoxicity was observed. Environ. Mol. Mutagen., 2008. Published 2008 Wiley‐Liss, Inc.
Mutagenic potential of nitrenium ions of nitrobenzanthrones: Correlation between theory and experiment
Authors: Reynisson Jóhannes , Stiborová Marie , Martínek Václav , Gamboa da Costa Gonçalo , Phillips David H. , Arlt Volker M. 
Published: July 2008

AbstractThe mutagenic activity of nine substituted nitrobenzanthrone (NBA) derivatives was recently established in the Ames assay and ranged from near inactivity to extremely high mutagenic activity (Takamura‐Enya et al. 2006: Mutagenesis 21:399–404). Using thermochemical and molecular modeling techniques, the activation pathway of these NBA derivatives, namely 1‐nitro‐, 2‐nitro‐, 3‐nitro‐, 9‐nitro‐, 11‐nitro‐, 1,9‐dinitro‐, 3,9‐dinitro‐, 3,11‐dinitro‐, and 3,9,11‐trinitrobenzanthrone, and the formation of the corresponding aryl‐nitrenium ions, were investigated using density functional theory calculations. The calculated properties of the NBA derivatives were systematically compared with their bacterial mutagenic potency. Accommodation of the ligand substrates into the binding pocket of the bacterial nitroreductases was not sterically inhibited for the NBAs. Moreover, electron affinities, water elimination energies, esterification, and solvolysis energies did not reveal any possible links with the observed mutagenic potency of the NBAs. However, a strong negative linear correlation was found when the relative energies of the nitrenium ions of the mono and disubstituted NBAs were plotted against the logarithm of the mutagenic potency of the NBAs found in the different Salmonella typhimurium strains. Therefore, our data clearly indicate that the stability of the nitrenium ions is one critical determinant of the mutagenic potency of NBAs in Salmonella tester strains. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Evaluation of putative hazard tests under background risk heterogeneity
Authors: Liu Yuan , Lawson Andrew B. , Ma Bo 
Published: July 2008

AbstractIn this paper, an evaluation of some tests for adverse health effects around fixed locations (putative hazard sites) is made. We address the situation where a heterogeneous background is included both in terms of correlated and uncorrelated heterogeneity (UH). In addition, we examine a set of tests for case event data (residential case addresses) including both distance and directional effects. The tests include distance and directional score tests (DIR), integrated intensity tests, the Besag & Newell (BES) test, and Kulldorff's focus clustering scan test. Monte Carlo power of the tests is evaluated and power curves are finally presented. Interesting results from this work include the lack of power found when correlated heterogeneity (CH) is present. This is not found with UH. The BES and Scan tests have lower power than the integrated intensity tests and score tests in general. The integrated intensity test demonstrates its omnibus ability to detect either distance or directional effects. Copyright © 2008 John Wiley & Sons, Ltd.
A hierarchical model for non‐stationary multivariate extremes: a case study of surface‐level ozone and NOxdata in the UK
Authors: Eastoe Emma F. 
Published: July 2008

AbstractWithin the last couple of decades much effort has been put into monitoring and analysing air pollution levels in an attempt to improve both our understanding of the scientific mechanisms involved and our ability to make predictions of future levels. In this paper we use extreme value methods to produce a statistical model for the joint distribution of surface‐level ozone (O3), nitric oxide (NO) and nitrogen dioxide (NO2) daily maxima, observed at a single urban location in the UK. Much recent work on the statistical analysis of extreme values has focused on methods for multivariate extremes, however, for all of the existing methods, it is unclear how to model non‐stationary data. By extending the pre‐processing method for the analysis of the extremes of non‐stationary univariate processes, we propose a hierarchical modelling approach for non‐stationary multivariate processes. This method allows prediction of the probabilities of any marginal or joint extreme events for non‐stationary multivariate data. We illustrate this by predicting marginal return levels for each of the pollutants of interest and then looking at the bivariate distribution of NO and NO2, conditional on ozone achieving a given marginal return level. Copyright © 2008 John Wiley & Sons, Ltd.
A buffered impact damper for multi‐degree‐of‐freedom structural control
Authors: Li Kuinian , Darby Antony P. 
Published: July 2008

AbstractThe results of an experimental investigation into the use of a buffered impact damper for controlling the dynamic response of an MDOF (multi‐degree‐of‐freedom) structure are presented in this paper. Free and forced vibration tests of a three‐DOF test structure equipped with a buffered impact damper are performed to evaluate the resulting damping effect and impact characteristics. The effect of damper parameters, such as clearance, and excitation type on the performance of the impact damper is also investigated. The performance of the buffered impact damper is compared with that of an equivalent conventional rigid impact damper. It is found that the buffered impact damper not only significantly reduces the peak contact force and the associated accelerations and noise generated by collisions but can also substantially enhance the damping effect over a wide range of frequencies, encompassing the natural frequencies of the test structure. Copyright © 2008 John Wiley & Sons, Ltd.
Dual high‐strength steel eccentrically braced frames with removable links
Authors: Dubina D. , Stratan A. , Dinu F. 
Published: July 2008

AbstractStructural damage in buildings designed according to the dissipative design philosophy can be significant, even under moderate earthquakes. Repair of damaged members is an expensive operation and may affect building use, which in turn increases the overall economic loss. If damage can be isolated to certain dissipative members realized to be removable following an earthquake, the repair costs and time of interruption of building use can be reduced. Dual structural configurations, composed of a rigid subsystem with removable ductile elements and a flexible subsystem, are shown to be appropriate for the application of removable dissipative element concept. Eccentrically braced frames with removable links connected to the beams using flush end‐plate bolted connections are investigated as a practical way of implementing this design concept. High‐strength steel is used for members outside links in order to enhance global seismic performance of the structure by constraining plastic deformations to removable links and reducing permanent drifts of the structure. Copyright © 2008 John Wiley & Sons, Ltd.
On the use of the notion of suitable weak solutions in CFD
Authors: Guermond Jean‐Luc 
Published: July 2008

AbstractThe notion of suitable weak solutions for the three‐dimensional incompressible Navier–Stokes equations together with some standard regularization techniques for constructing these solutions is reviewed. The novel result presented in this paper is that Faedo–Galerkin weak solutions to the Navier–Stokes equations are suitable provided they are constructed using finite‐dimensional spaces having a discrete commutator property and satisfying a proper inf–sup condition. Low‐order mixed finite element spaces appear to be acceptable for this purpose. Connections between the notion of suitable solutions and LES modeling are investigated. A proposal for a large eddy scale model based on the notion of suitable solutions is made and numerically illustrated. Copyright © 2008 John Wiley & Sons, Ltd.
Onset of mixing layer instability in flow past a plate
Authors: Mittal Sanjay 
Published: July 2008

AbstractA global stability analysis of the flow past a flat plate, normal to the flow, is carried out to determine the critical Re for the onset of convective instability of the mixing‐layer‐type modes. To suppress the primary wake mode, which leads to von Karman vortex shedding, flow past one half of the plate is studied and symmetry conditions are enforced along the wake centerline. The linearized perturbation equations for an incompressible flow are written in a moving frame of reference that travels with the perturbation and solved using a stabilized finite element method. The critical Re for the onset of convective instability is found to be 22, approximately, for H=5. Here, H is the distance of the lateral boundary from the plate centerline. Computations have also been carried out for H=10 and 20. The critical Re decreases with increase in H. Excellent agreement is observed between the results from global stability analysis and direct time integration of linearized disturbance equations. The results from the global analysis are compared with earlier reported results from local analysis of a Gaussian wake profile. Copyright © 2008 John Wiley & Sons, Ltd.
Hilfe für den Zappelphilipp
Authors: Warnke Andreas , Renner Tobias , Romanos Marcel , Lesch Klaus‐Peter 
Published: July 2008

AbstractHyperaktiv und abgelenkt: Mehr als 650 000 Kinder und Jugendliche in Deutschland leiden unter ADHS. Forscher sind den Ursachen auf der Spur – und neuen Therapien
„Achtung, Zigeuner!”︁
Authors: Uerlings Herbert , Patrut Iulia‐Karin 
Published: July 2008

AbstractZwischen Verklärung und Vernichtung: Der gesellschaftliche Umgang mit dem „fahrenden Volk”︁ wandelte sich über Jahrhunderte immer wieder. Bis heute prägen Stereotype die Wahrnehmung der Sinti und Roma
NMR Studies of Proton Transport in Anhydrous Polymer Electrolytes for High Temperature Fuel Cells
Authors: Every H. A. , Ionescu L. D. , de Heer M. P. , Álvarez‐Gallego Y. , Janssen G. J. M. 
Published: July 2008

AbstractThis paper presents an NMR study of the dynamic processes related to proton transport in a new polymer consisting of two blocks – poly(2,6‐diphenylphenol) (P3O) and an imidazole functionalised poly(2,6‐dimethylphenol) (imi‐PPE) – and subsequently doped with polyphosphoric acid (PPA). From 1H and 31P NMR relaxation and diffusion measurements of the individual homopolymers and block copolymer, it was observed that addition of PPA significantly enhanced the mobility of imi‐PPE and the imi‐block copolymer, but not of P3O. The similarity in 1H T2 values between imi‐PPE and the imi‐block copolymer suggests that the relaxation behaviour in the block copolymer is dominated by the imi‐PPE phase. 1H diffusion in P3O and the imi‐block copolymer were comparable to pure PPA, suggesting that the proton diffusion is similar in each case. For imi‐PPE, the diffusion coefficients were several orders of magnitude lower, reflecting a restricted diffusion process that is not indicative of the proton mobility. For all three polymers, the 31P T2 relaxation behaviour and inability to measure 31P diffusion coefficients imply hindered translational motion of the phosphonate groups. From these results, it can be concluded that hydrogen bonds between the phosphoric acid and the polymer form a network that facilitates proton transport via a hopping mechanism.
Proton Conducting Membranes Based on Benzimidazole Sulfonic Acid Doped Sulfonated Poly(Oxadiazole–Triazole) Copolymer for Low Humidity Operation
Authors: Ponce M. L. , Boaventura M. , Gomes D. , Mendes A. , Madeira L. M. , Nunes S. P. 
Published: July 2008

AbstractThis work reports for the first time the preparation of sulphonated poly(oxadiazole–triazole) copolymer membranes doped with amphoteric molecule, 1H‐benzimidazole‐2‐sulphonic acid and their characterisation as proton conductors at 120 °C and low humidity. The membranes had not only high proton conductivities, up to 4 × 10–3 S cm–1 at 120 °C and low relative humidity (5 and 10%), but also had good mechanical properties with a storage modulus of about 3 GPa at 300 °C and high thermal stability with Tg up to around 420 °C. Because of their superior ion conducting and mechanical properties they have potential as a proton conducting membrane for fuel cell applications, in particular at high temperature and extremely low‐humidity conditions.