bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequential processes of phosphate limitation and of phosphate release in streptomycin fermentations
Authors: Müller P. J. , Christner A. , Ozegowski J. H. 
Published: July 2010

AbstractThe significance of the sequential processes of phosphate limitation and of phosphate release from medium constituents is demonstrated in technical streptomycin fermentations. The phosphate limitation initiated the streptomycin synthesis as well as the formation of phosphatases and protease. In later periods of the process the phosphate release influences especially the enzyme formation.
Influence of phosphate concentration on the respiratory activity of Azotobacter vinelandii
Authors: Haldenwang L. , Behrens U. 
Published: July 2010

AbstractAzotobacter vinelandii was grown in batch cultures supplied with ammonia as an N‐source and phosphate at limiting concentration. After phosphate depletion the respiratory rate was affected in a characteristic way. The oxygen consumption during growth and the phase following growth was substantially higher than in cultures amply supplied with phosphate. It is suggested that phosphate limitation impairs the oxidative phosphorylation and stimulates the substrate phosphorylation which leads to a higher degree of respiratory NAD(P)H oxidation due to changes in the branched electron transport system.
Ultrastructural characterization of core structures and paracrystalline inclusion bodies in L‐form cells of streptomycetes
Authors: Gumpert J. 
Published: July 2010

AbstractProtoplast type L‐form cells of Streptomyces hygroscopicus and S. griseus contain different types of inclusion bodies. Cytoplasmic cores and paracrystalline structures are peculiar inclusions which could not be observed in normal parent bacteria. The cytoplasmic cores are 1–4 μm long and 0.05–0.25 μm broad straight and stiff non‐tubular structures consisting of homogeneous moderate electron opaque material. Paracrystalline inclusions have side‐lengths between 0.2 and 0.5 μm and show a characteristic pattern of 15–20 nm thick straight dark lines and electron lucent intervening spaces of 20–30 nm. Both cytoplasmic cores and paracrystalline inclusions are apparently proteins. Their occurrence in L‐form cells indicates an altered synthesis of one or several proteins in these cell types.
Ciprofloxacin up‐regulates tendon cells to express matrix metalloproteinase‐2 with degradation of type I collagen
Authors: Tsai Wen‐Chung , Hsu Chih‐Chin , Chen Carl P.C. , Chang Hsiang‐Ning , Wong Alice M.K. , Lin Miao‐Sui , Pang Jong‐Hwei S. 
Published: July 2010

AbstractCiprofloxacin‐induced tendinopathy and tendon rupture have been previously described, principally affecting the Achilles tendon. This study was designed to investigate the effect of ciprofloxacin on expressions of matrix metalloproteinases (MMP)‐2 and ‐9, tissue inhibitors of metalloproteinase (TIMP)‐1 and ‐2 as well as type I collagen in tendon cells. Tendon cells intrinsic to rat Achilles tendon were treated with ciprofloxacin and then underwent MTT (tetrazolium) assay. Real‐time reverse‐transcription polymerase chain reaction (RT‐PCR) and Western blot analysis were used, respectively, to evaluate the gene and protein expressions of type I collagen, and MMP‐2. Gelatin zymography was used to evaluate the enzymatic activities of MMP‐2 and ‐9. Reverse zymography was used to evaluate TIMP‐1 and ‐2. Immunohistochemical staining for MMP‐2 in ciprofloxacin‐treated tendon explants was performed. Collagen degradation was evaluated by incubation of conditioned medium with collagen. The results revealed that ciprofloxacin up‐regulated the expression of MMP‐2 in tendon cells at the mRNA and protein levels. Immunohistochemistry also confirmed the increased expressions of MMP‐2 in ciprofloxacin‐treated tendon explants. The enzymatic activity of MMP‐2 was up‐regulated whereas that of MMP‐9, TIMP‐1 or TIMP‐2 was unchanged. The amount of secreted type I collagen in the conditioned medium decreased and type I collagen was degraded after ciprofloxacin treatment. In conclusion, ciprofloxacin up‐regulates the expressions of MMP‐2 in tendon cells and thus degraded type I collagen. These findings suggest a possible mechanism of ciprofloxacin‐associated tendinopathy. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:67–73, 2011
Short‐time clay‐mineral evolution in a soil chronosequence in Oléron Island (France)
Authors: Caner Laurent , Joussein Emmanuel , Salvador‐Blanes Sébastien , Hubert Fabien , Schlicht Jean‐Frédéric , Duigou Nelly 
Published: July 2010

AbstractMajor weathering sequences in soils are well established; however, knowledge on rates of mineral transformations remains unknown, because it is often difficult to date precisely soil processes. This work was carried out on soils developed on recent (< 188 y) sand dunes on the W coast of Oléron Island (France). The coast has been protected against marine and wind erosion by constructing five consecutives barriers close to the coastline since 1820 (1820, 1864, 1876, 1889, 1948) defining the maximum age of the soil parent material, as before the areas between the barriers were under water. Soils on the older dunes have low clay content (> 94% of sand) and exhibit a bleached E horizon that overlies a yellowish brown B horizon. The process responsible for their formation is podzolization promoted by the high permeability of the material and complexing organic matter produced by coniferous vegetation. Initial mineralogy of C horizons is homogenous and constituted of chlorite, illite, illite/smectite mixed‐layer minerals, and kaolinite, quartz, calcite (≈ 8% related to shell fragments), and feldspars. The initial clay‐mineral assemblage of the E horizons is dominated by illite (well‐crystallized WCI and poorly crystallized PCI) and chlorite. With progressive podzolization, poorly crystallized illite is first transformed to illite/smectite mixed‐layer minerals and in a further step into smectite. In addition, transformation of well‐crystallized illite leads to formation of ordered illite/smectite mixed‐layer minerals in the E horizons, which is not commonly described in soils. In the B horizons, illite/smectite mixed‐layer minerals are present with traces of smectite, as well as Al and Fe oxi‐hydroxides as revealed by DCB and oxalate chemical extractions. This chronosequence illustrates that over short distances and short time (< 188 y) intense mineral weathering and soil development occur. Major clay‐mineral changes occur between 132 and 188 y in agreement with development of the pine forest producing acidic litter.
Synthesis of New Polysialic Acid Derivatives
Authors: Su Yi , Kasper Cornelia , Kirschning Andreas , Dräger Gerald , Berski Silke 
Published: July 2010

AbstractIn this paper we report the first synthesis of novel polysialic acid derivatives which is initiated by treatment of polysialic acid with EDC‐HCl to yield the inter‐residual δ‐lactone. Subsequent reaction with amines or hydrazine gives the corresponding polysialic acid amides and hydrazide. Alkylation of the tetrabutylammonium salt of polysialic acid yields polysialic acid esters. In contrast a variety of N‐derivatives of polysialic acid can be prepared starting from deacetylated polysialic acid. The N‐derivatives prepared in this communication can be used for the Cu‐catalyzed as well as Cu‐free “click” chemistry.
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Formation of Poly(propylene)‐Based Biocomposite Films and Their Use in the Attachment of Methylene Blue
Authors: Cavallo Jesica A. , Gomez Cesar G. , Strumia Miriam C. 
Published: July 2010

AbstractBiocomposite PP‐g‐PAAc‐CS films based on PP were generated and utilized as support of methylene blue, a thiazidic dye. Using a photograft polymerization of acrylic acid, the PP film was functionalized with carboxyl groups (PP‐g‐PAAc), which attached chitosan by electrostatic bond. A longer poly(acrylic acid) chain or a higher CS immobilization temperature led to a higher chain interpenetration and crosslinking reaction. Immobilized MB confirmed to possess redox activity from its reaction with ascorbic acid, where the dye decomposition rate ($R'_{\rm d} $) increases together with the chain interpenetration, then decreasing with the increase in the crosslinking degree.magnified image
Polarizability of DNA Block Copolymer Nanoparticles Observed by Electrostatic Force Microscopy
Authors: Sowwan Mukhles , Faroun Maryam , Mentovich Elad , Ibrahim Imad , Haboush Shayma , Alemdaroglu Fikri Emrah , Kwak Minseok , Richter Shachar , Herrmann Andreas 
Published: July 2010

AbstractIn this study, DNA block copolymer (DBC) micelles with a polystyrene (PS) core and a single‐stranded (ss) DNA shell were doped with ferrocene (Fc) molecules. Tapping mode atomic force microscopy (AFM) was used to study the morphology of the doped and undoped block copolymer aggregates. We show that introducing Fc molecules into the hydrophobic core does not affect the structural properties such as shape or size. In contrast, doping with Fc significantly changes the micelles' electrical properties, namely their polarizability. Electrostatic force microscopy (EFM) measurements reveal that the undoped micelles show no significant polarization signal, while the Fc‐doped aggregates exhibit strongly enhanced polarizability. Furthermore, the nucleic acid moieties were utilized in combination with complementary ssDNA strands to assemble single particles into linear arrays of DBC nanoobjects. The ability to tune the electrostatic properties of the polymer core and the presence of nucleic acids might open the way for using these bioorganic nanoparticles as building blocks for nanoelectronic or biosensing devices.magnified image
Multicomponent Phase Change Microfibers Prepared by Temperature Control Multifluidic Electrospinning
Authors: Wang Nü , Chen Hongyan , Lin Ling , Zhao Yong , Cao Xinyu , Song Yanlin , Jiang Lei 
Published: July 2010

AbstractMulticomponent phase change microfibers, which can storage and release thermal energy in a stepwise manner, are firstly prepared through a facile one‐step multifluidic compound‐jet electrospinning with temperature control. The multiresponsive effect benefits from a special multichannel tubular microstructure that could controllably encapsulate different phase change materials into the channels independently. Aside from the fabrication of multicomponent phase change microfibers, the melt multifluidic compound‐jet electrospinning is promising for applications related to microencapsulation and multifunctional material fields.magnified image
Effect of Finite Extensibility on the Equilibrium Chain Size
Authors: Miao Bing , Vilgis Thomas A. , Poggendorf Stefanie , Sadowski Gabriele 
Published: July 2010

AbstractWe investigate the finite‐extensibility effect on the equilibrium size of a single polymer chain by using a Flory‐type calculation. The finite extensibility of the chain is effectively taken into account by modifying the Gaussian stretching energy to a non‐Gaussian form which recovers the harmonic spring behavior in the limit of weak stretch and diverges when the chain extension approaches the total contour length. In general, the finite extensibility decreases the equilibrium size of the chain compared to that obtained from Flory's classic theory, due to a steeper free energy or effective potential of the chain generated by the finite‐extensibility effect. It is illustrated clearly that, for a chain with a short contour length and/or with strong repulsions between monomers, the finite‐extensibility correction is important and necessary to be taken into account. A typical system where the finite extensibility plays an important role is suggested to be the highly charged and highly crosslinked hydrogel.magnified image
Measurement of alveolar oxygen partial pressure in the rat lung using Carr‐Purcell‐Meiboom‐Gill spin–spin relaxation times of hyperpolarized 3He and 129Xe at 74 mT
Authors: Kraayvanger Ryan J. , Bidinosti Christopher P. , Dominguez‐Viqueira William , Parra‐Robles Juan , Fox Matthew , Lam Wilfred W. , Santyr Giles E. 
Published: July 2010

AbstractRegional measurement of alveolar oxygen partial pressure can be obtained from the relaxation rates of hyperpolarized noble gases, 3He and 129Xe, in the lungs. Recently, it has been demonstrated that measurements of alveolar oxygen partial pressure can be obtained using the spin–spin relaxation rate (R2) of 3He at low magnetic field strengths (<0.1 T) in vivo. R2 measurements can be achieved efficiently using the Carr‐Purcell‐Meiboom‐Gill pulse sequence. In this work, alveolar oxygen partial pressure measurements based on Carr‐Purcell‐Meiboom‐Gill R2 values of hyperpolarized 3He and 129Xe in vitro and in vivo in the rat lung at low magnetic field strength (74 mT) are presented. In vitro spin–spin relaxivity constants for 3He and 129Xe were determined to be (5.2 ± 0.6) ×10−6 Pa−1 sec−1 and (7.3 ± 0.4) ×10−6 Pa−1 s−1 compared with spin‐lattice relaxivity constants of (4.0 ± 0.4) ×10−6 Pa−1 s−1 and (4.3 ± 1.3) × 10−6 Pa−1 s−1, respectively. In vivo experimental measurements of alveolar oxygen partial pressure using 3He in whole rat lung show good agreement (r2 = 0.973) with predictions based on lung volumes and ventilation parameters. For 129Xe, multicomponent relaxation was observed with one component exhibiting an increase in R2 with decreasing alveolar oxygen partial pressure. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Time‐resolved bolus‐chase MR angiography with real‐time triggering of table motion
Authors: Johnson Casey P. , Haider Clifton R. , Borisch Eric A. , Glockner James F. , Riederer Stephen J. 
Published: July 2010

AbstractTime‐resolved bolus‐chase contrast‐enhanced MR angiography with real‐time station switching is demonstrated. The Cartesian acquisition with projection reconstruction‐like sampling (CAPR) technique and high 2D sensitivity encoding (SENSE) (6× or 8×) and 2D homodyne (1.8×) accelerations were used to acquire 3D volumes with 1.0‐mm isotropic spatial resolution and frame times as low as 2.5 sec in two imaging stations covering the thighs and calves. A custom real‐time system was developed to reconstruct and display CAPR frames for visually guided triggering of table motion upon passage of contrast through the proximal station. The method was evaluated in seven volunteers. High‐spatial‐resolution arteriograms with minimal venous contamination were consistently acquired in both stations. Real‐time stepping table contrast‐enhanced MR angiography is a method for providing time‐resolved images with high spatial resolution over an extended field‐of‐view. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Computational modelling of shaped metal deposition
Authors: Anca Andrés , Fachinotti Víctor D. , Escobar‐Palafox Gustavo , Cardona Alberto 
Published: July 2010

AbstractShaped metal deposition (SMD) is a novel process for rapid prototyping that employs tungsten inert gas (TIG) welding controlled by a robot inside an inert gas chamber to build parts by successive layer deposition. This process can be enhanced through modelling and control. Industries are interested in developing systematized models to explain observed phenomena and to predict processing conditions for process planning and optimization. In this work, thermal and mechanical finite element (FE) modelling of SMD is presented. The thermal problem is solved with linear tetrahedral finite FEs that take into account the liquid/solid phase change phenomenon. The mechanical problem is solved with hexahedral elements with tri‐linear interpolation of displacements and constant interpolation of mean stresses (Q1– P0). Special techniques to account for material addition were developed, based on activation/deactivation of FEs. Numerical tests were conducted to determine the heat source model parameters. An experiment using Ti‐6Al‐4V material was developed to validate the formulation. The test consisted of a TIG‐wash procedure (arc passing without wire feeding to preheat the plate) followed by a single welding layer. The results, including temperatures and residual displacements, are compared with those obtained with the finite element method (FEM) code. Finally, a multilayer SMD numerical example is presented. Copyright © 2010 John Wiley & Sons, Ltd.
A Cartesian ghost‐cell multigrid Poisson solver for incompressible flows
Authors: Ma Z. H. , Qian L. , Causon D. M. , Gu H. B. , Mingham C. G. 
Published: July 2010

AbstractIn this paper, a simple Cartesian ghost‐cell multigrid Poisson solver is proposed for simulating incompressible fluid flows. The flow field is discretized efficiently on a rectangular mesh, in which solid bodies are immersed. A small number of ghost mesh cells and their symmetric image cells are distributed in the vicinity of the solid boundary. With the aid of the ghost and image cells, the Dirichlet and Neumann boundary conditions can be implemented effectively. Chorin's fractional‐step projection method is adopted for the coupling of velocity and pressure for the solution of the Navier–Stokes equations. Point‐wise Gauss–Seidel iteration is used to solve the pressure Poisson equation. To speed up the convergence of the solution to the corresponding linear system, sub‐level coarse meshes embedded with ghost and image cells are also introduced and operated in a sequential V‐cycle. Several test cases including the classical ideal incompressible flow around a cylinder, a lid‐driven cavity flow and viscous flow past a fixed/rotating cylinder are presented to demonstrate the accuracy and efficiency of the current approach. Copyright © 2010 John Wiley & Sons, Ltd.
Lucayan–Taíno burials from Preacher's cave, Eleuthera, Bahamas
Authors: Schaffer W. C. , Carr R. S. , Day J. S. , Pateman M. P. 
Published: July 2010

AbstractIn March 2007, three prehistoric skeletons were excavated and analysed from Preacher's Cave on the northern aspect of the island of Eleuthera in the Bahama archipelago. The human skeletal remains represent two males and one female dating toAD800–1300. The first is a female in the 30s with mild osteoarthritis of the joints and spine and several healed fractures who may have been an important community elder. The second is a male in the 20s with Schmorl's nodes who may have been a shaman or even a victim of interpersonal violence. The third is a male in the mid to late 20s also with marginal osteoarthritis of the joints and spine who may have been a ceremonial leader and village headman. The high incidence of carious lesions implies a cariogenic diet possibly rich in starchy foodstuffs or even fructose. The presence of grave goods and plaited mats suggest that at least two individuals may have been of high status. This study emphasises the significance of caves to Lucayan–Taíno mythology, cosmology and mortuary practice. Copyright © 2010 John Wiley & Sons, Ltd.
Hamiltonian two‐degrees‐of‐freedom control of chemical reactors
Authors: Costanza Vicente , Rivadeneira Pablo S. 
Published: July 2010

AbstractA novel unified approach to two‐degrees‐of‐freedom control is devised and applied to a classical chemical reactor model. The scheme is constructed from the optimal control point of view and along the lines of the Hamiltonian formalism for nonlinear processes. The proposed scheme optimizes both the feedforward and the feedback components of the control variable with respect to the same cost objective. The original Hamiltonian function governs the feedforward dynamics, and its derivatives are part of the gain for the feedback component. The optimal state trajectory is generated online, and is tracked by a combination of deterministic and stochastic optimal tools. The relevant numerical data to manipulate all stages come from a unique off‐line calculation, which provides design information for a whole family of related control problems. This is possible because a new set of PDEs (the variational equations) allow to recover the initial value of the costate variable, and the Hamilton equations can then be solved as an initial‐value problem. Perturbations from the optimal trajectory are abated through an optimal state estimator and a deterministic regulator with a generalized Riccati gain. Both gains are updated online, starting with initial values extracted from the solution to the variational equations. The control strategy is particularly useful in driving nonlinear processes from an equilibrium point to an arbitrary target in a finite‐horizon optimization context. Copyright © 2010 John Wiley & Sons, Ltd.
Production of highly conductive textile viscose yarns by chemical vapor deposition technique: a route to continuous process
Authors: Bashir Tariq , Skrifvars Mikael , Persson Nils‐Krister 
Published: July 2010

AbstractAn oxidative chemical vapor deposition (OCVD) process was used to coat flexible textile fiber (viscose) with highly conductive polymer, poly (3,4‐ethylenedioxythiophene) (PEDOT) in presence of ferric (III) chloride (FeCl3) oxidant. OCVD is a solvent free process used to get uniform, thin, and highly conductive polymer layer on different substrates. In this paper, PEDOT coated viscose fibers, prepared under specific conditions, exhibited high conductivity 14.2 S/cm. The effects of polymerization conditions, such as polymerization time, oxidant concentration, dipping time of viscose fiber in oxidant solution, and drying time of oxidant treated viscose fiber, were carefully investigated. Scanning electron microscopy (SEM) and FT‐IR analysis revealed that polymerization of PEDOT on surface of viscose fiber has been taken place and structural analysis showed strong interactions between PEDOT and viscose fiber. Thermogravimetric analysis (TGA) was employed to investigate the amount of PEDOT in PEDOT coated viscose fiber and interaction of PEDOT with viscose fiber. The effect of PEDOT coating on the mechanical properties of the viscose fiber was evaluated by tensile strength testing of the coated fibers.The obtained PEDOT coated viscose fiber having high conductivity, could be used in smart clothing for medical and military applications, heat generation, and solar cell demonstrators. Copyright © 2010 John Wiley & Sons, Ltd.
Antithrombotic therapies in patients with heart failure: hypothesis formulation from a research database
Authors: Yuan Zhong , Weinstein Rachel , Zhang John , Cheng Mei , Griffin George , Zolynas Robert , Plotnikov Alexei N. , Lee Mary S. , Oppenheimer Leonard , Burton Paul 
Published: July 2010

AbstractPurposeHeart failure is a significant public health problem. The present study is intended to explore in a research database whether antithrombotic therapies (ATTs) affect cardiovascular outcomes in patients with incident heart failure (IHF).MethodsUsing the United Kingdom Health Improvement Network research database, several multivariable models (including logistic and Cox's regression models, as well as propensity score methods) were used to examine all‐cause mortality and clinical outcomes among five treatment groups.ResultsThe cohort included 24 554 patients with IHF (50.2% men), with a mean age (standard deviation [SD]) of 76.4 (11.0) years. Nearly three‐fourths of patients received at least one form of ATT. Patients receiving ATTs tended to be younger and more likely to be men, and had more cardiovascular comorbidities. During the 18‐month follow‐up period, the mortality rates were 11.1%, 14.6%, 17.8%, 19.5%, and 32.6% for warfarin combination therapy, warfarin alone, clopidogrel therapy, aspirin (ASA) alone, and no therapy, respectively, yielding odds ratios (95%confidence intervals [CI]) relative to no therapy of 0.28 (0.24, 0.33), 0.38 (0.34, 0.43), 0.46 (0.40, 0.52), and 0.49 (0.45, 0.53) for each therapy group, accordingly. The use of ATTs also appeared to be associated with a reduced risk for ischemic or thrombotic events.ConclusionsThese data contribute to the formulation of the hypothesis that use of ATTs in clinical practice decreases the risk of morbidity and mortality in patients with IHF, although findings require further confirmative studies. Copyright © 2010 John Wiley & Sons, Ltd.