bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Synthesis of an Ionomycin Calcium Complex
Authors: Gao Zhanghua , Li Yingfa , Cooksey John P. , Snaddon Thomas N. , Schunk Stefan , Viseux Eddy M. E. , McAteer Stephen M. , Kocienski Philip J. 
Published: June 2009

AbstractCaught in the middle: The ionomycin calcium complex (see structure; O red, Ca green) was the target of an approach featuring the efficient asymmetric synthesis of an allene by a copper(I)‐mediated anti‐selective SN2′ reaction, a highly stereoselective gold(III)‐catalyzed cycloisomerization of an α‐hydroxyallene, and a Rh‐catalyzed rearrangement of an α‐diazo‐β‐hydroxyketone.magnified image
Hydrogen Evolution at Liquid–Liquid Interfaces
Authors: Hatay Imren , Su Bin , Li Fei , Partovi‐Nia Raheleh , Vrubel Heron , Hu Xile , Ersoz Mustafa , Girault Hubert H. 
Published: June 2009

AbstractBlowing bubbles: Hydrogen evolution by proton reduction with [(C5Me5)2Fe] occurs at a soft interface between water and 1,2‐dichloroethane (DCE). The reaction proceeds by proton transfer assisted by [(C5Me5)2Fe] across the water–DCE interface with subsequent proton reduction in DCE. The interface essentially acts as a proton pump, allowing hydrogen evolution by directly using the aqueous proton.magnified image
Impact of impregnation with boron compounds on the surface hardness and abrasion resistance of some varnished woods
Authors: Atar Musa , Uysal Burhanettin , Saríca Mutlu 
Published: June 2009

AbstractThis study was performed to determine the impact of impregnation with boron compounds on the surface hardness and abrasion resistance of some varnished woods. For this purpose, test specimens prepared from Oriental beech, White oak, Scotch pine, and Uludag fir, which met the requirements of ASTM D 358, were impregnated according to ASTM D 1413‐99 with boric acid (Ba), borax (Bx), and boric acid + borax (Ba+Bx) by the vacuum technique. After impregnation, the surfaces are coated with synthetic (Sn), water‐borne (Wb) and acid hardening (Ah) varnishes in accordance with ASTM D 3023. the surface hardness of specimens after the varnishing process was determined in accordance with ASTM D 4366. The abrasion resistance of specimens after the varnishing process was determined in accordance with TS 4755. According to the wood type, impregnation material and varnish type, the surface hardness was the highest for Oriental beech impregnated with borax + boric acid and acid hardening varnish and the lowest for Uludag fir impregnated with borax + boric acid and synthetic varnish. According to the wood type, impregnation material and varnish type, the abrasion resistance was the highest for Oriental beech impregnated with borax + boric acid and acid hardening varnish and the lowest for Scotch pine impregnated with borax + boric acid and synthetic varnish. Those results should be taken into account for applications like parquet, flooring etc., where the surface hardness and abrasion resistance values are very important. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Investigation of electrical conduction mechanism in double‐layered polymeric system
Authors: Shukla Prashant , Gaur M. S. 
Published: June 2009

AbstractThe electrical conduction in solution‐grown polymethylmethacrylate (PMMA), polyvinylidenefluoride (PVDF) and PMMA‐PVDF double‐layered samples in the sandwich configuration (metal‐polymer‐metal) was investigated at different fields in the range 100–120 kV/cm as a function of temperature in the range 293–423 K for samples of constant thickness of about 50 μm. Certain effects which lead to a large burst of current immediately after the application of field were observed in double‐layered samples. An attempt was made to identify the nature of the current by comparing the observed dependence on electric field, electrode material and temperature with the respective characteristic features of the existing theories on electrical conduction. The observed linear I‐V characteristics show that the electrical conduction follows Pool‐Frenkel mechanism in PMMA and PVDF samples. Whereas, the non‐linear behavior of current‐voltage measurements in PMMA‐PVDF double‐layered samples have been interpreted on the basis of space charge limited conduction (SCLC) mechanism. The conductivity of the polymer films increased on formation of their double‐layer laminates. The polymer‐polymer interface act as charge carrier trapping centres and provides links between the polymer molecules in the amorphous region. The interfacial phenomenon in polymer‐polymer heterogeneous system has been interpreted in terms of Maxwell‐Wagner model. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cellulose–chitosan interpenetrating polymer network for electro‐active paper actuator
Authors: Cai Zhijiang , Kim Jaehwan 
Published: June 2009

AbstractIn this article, the cellulose‐chitosan interpenetrating polymer network (IPN) films were prepared and fabricated as the electro‐active paper actuator. The characteristics of the cellulose–chitosan IPN films were examined by SEM, FT‐IR, XRD, DSC, and tensile test. The performance of the IPNs based actuator was evaluated in terms of bending displacement with respect to the actuation frequency, voltages, humidity levels, chitosan content, and time variation. It was observed that with chitosan content increasing in the IPNs, the crystallinity decreased and the network became denser, which caused the Young's modulus to increase. Chitosan content in IPNs also significantly affected the bending performance. The optimum IPN weight ratio of cellulose and chitosan was 60 : 40. The maximum bending displacement of 7.2 mm was found at 80% relative humidity level. In terms of durability, the bending lifetime at 70% humidity level was about 10 h with 17% performance degradation. More issues on the actuator performance and durability are addressed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of higher soluble nanostructured polyaniline by vapor‐phase polymerization and determination of its crystal structure
Authors: Bhadra Sambhu , Lee Joong Hee 
Published: June 2009

AbstractHigher soluble nanostructured polyaniline was prepared by vapor‐phase polymerization after passing aniline vapor through an aqueous acidic solution of ammonium persulfate (PANI‐V). Polyaniline was also synthesized by the conventional oxidative polymerization method (PANI‐C) in an aqueous medium for the comparison of its properties with PANI‐V. PANI‐V exhibited lower conductivity but higher hydrophilicity and higher solubility (2–3 times) in different solvents, such as tetrahydrofuran, N‐methyl‐2‐pyrrolidone, dimethylsulfoxide, N,N‐dimethyl formamide, and m‐cresol at room temperature compared with that of PANI‐C. The thermal stability of PANI‐V was higher than that of PANI‐C. In‐depth investigations of the crystal structures of PANI‐C and PANI‐V were performed through powder X‐ray diffraction analysis. The PANI‐V showed a less ordered structure with a lower crystallinity and crystallite size and with a higher d‐spacing and interchain separation compared with PANI‐C. The unit cell volume of PANI‐V was significantly higher with a greater number of atoms in the unit cell than that of PANI‐C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and properties of biocomposites based on jute fibers and blend of plasticized starch and poly(β‐hydroxybutyrate)
Authors: Belhassen Ramzi , Méndez José Alberto , Boufi Sami , López Joan Pere , Puig Josep , Pèlach Angels , Mutjé Pere 
Published: June 2009

AbstractIn this work, preparation and properties of biocomposites based on jute fibers and blend of plasticized starch and poly(β‐hydroxybutyrate) (PHB) have been investigated. Different amounts of glycerol and aliphatic polyesters (PHB) have been added to native starch to obtain a processable biodegradable matrix. In the same way natural jute fibers up to 30 wt % loading were added to improve the mechanical and thermal stability of the material. Tensile mechanical, thermal, and thermomecahnical analyses have been performed to characterize the ensuing materials. Significant enhancement in the mechanical properties and water sensitivity were noted by the addition of 8 wt % PHB. The fibers incorporation into the biopolymer matrix brings about an increase in both the mechanical strength and modulus as much higher as the fibers loading is important. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cloning and expression of the gene for an insect haemocyte anti‐aggregation protein (VPr3), from the venom of the endoparasitic wasp, Pimpla hypochondriaca
Authors: Dani M. Paulina , Richards Elaine H. 
Published: June 2009

AbstractA venom protein from the endoparasitic wasp, Pimpla hypochondriaca, was recently biochemically isolated. This protein possessed haemocyte anti‐aggregation activity in vitro and shares the same N‐terminal amino acid sequence as that deduced from a gene termed vpr3. The vpr3 gene was identified by sequence analysis of randomly isolated cDNAs from a P. hypochondriaca venom gland library. Presently, the gene for the full‐length sequence of mature VPr3 protein was amplified from the P. hypochondriaca venom gland cDNA library by PCR. The amplicon was directionally cloned into a pET expression vector so that recombinant VPr3 (rVPr3) would have an N‐terminal polyhistidine (His) tag. High levels of target protein expression were obtained following addition of IPTG (1 mM) and growth of the bacteria at 37°C for 5 h, or at 24°C for 20 h. Following lysis of bacteria grown at 37°C, the target protein partitioned into the insoluble fraction. However, at 24°C, a small amount of soluble protein was consistently detected. The amount of soluble rVPr3 was subsequently increased when the transformed bacteria were grown in Overnight Express Instant TB medium at 24°C. Soluble rVPr3 was purified utilizing the MagneHis Protein Purification System. Recombinant VPr3 was determined to have adverse effects on the cytoskeleton of Lacanobia oleracea haemocytes and to inhibit the ability of these cells to form aggregates in vitro. © 2009 Wiley Periodicals, Inc.
Managing polysemy and synonymy in science mapping using the mixtures of factor analyzers model
Authors: Kwakkel Jan H. , Cunningham Scott W. 
Published: June 2009

AbstractA new method for mapping the semantic structure of science is described. We assume that different researchers, working on the same set of research problems, will use the same words for concepts central to their research problems. Therefore, different research fields and disciplines should be identifiable by different words and the pattern of co‐occurring words. In natural language, however, there is quite some diversity because many words have multiple meaning. In addition, the same meaning can be expressed by using different words. We argue that traditional factor analytic and cluster analytic techniques are inadequate for mapping the semantic structure if such polysemous and synonymous words are present. Instead, an alternative model, the mixtures of factor analyzers (MFA) model, is utilized. This model extends the traditional factor analytic model by allowing multiple centroids of the dataset. We argue that this model is structurally better suited to map the semantic structure of science. The model is illustrated by a case study of the uncertainty literature sampled from data from the ISI Web of Science. The MFA model is applied with the goal of discovering multiple, potentially incommensurate, conceptualizations of uncertainty in the literature. In this way, the MFA model can help in creating understanding of the use of language in science, which can benefit multidisciplinary research and interdisciplinary understanding, and assist in the development of multidisciplinary taxonomies of science.
Measuring consistency for multiple taggers using vector space modeling
Authors: Wolfram Dietmar , Olson Hope A. , Bloom Raina 
Published: June 2009

AbstractA longstanding area of study in indexing is the identification of factors affecting vocabulary usage and consistency. This topic has seen a recent resurgence with a focus on social tagging. Tagging data for scholarly articles made available by the social bookmarking Website CiteULike (www.citeulike.org) were used to test the use of inter‐indexer/tagger consistency density values, based on a method developed by the authors by comparing calculations for highly tagged documents representing three subject areas (Science, Social Science, Social Software). The analysis revealed that the developed method is viable for a large dataset. The findings also indicated that there were no significant differences in tagging consistency among the three topic areas, demonstrating that vocabulary usage in a relatively new subject area like social software is no more inconsistent than the more established subject areas investigated. The implications of the method used and the findings are discussed.
Topological entropy and data rate for practical stability: a scalar case
Authors: Xie Li 
Published: June 2009

AbstractA special class of nonlinear systems,i.e.expanding piecewise affine discrete‐time scalar systems with limited data rate, is used to investigate the role of topological entropy and date rate in a practical stability problem. This special class of nonlinear system as an abstract model is an extension of discrete‐time unstable scalar systems, a well‐known model for quantized feedback design. For such systems with finite quantization levels, how to design a quantized feedback controller to achieve practical stability is considered as a boundability problem. Unlike the existing results about topological entropy for nonlinear stabilization and optimal control for linear systems, for the boundability problem under consideration, the feedback topological entropy defined in this paper is not equal to the minimum number of the quantization interval (i.e.the minimal information rate) and only provides a necessary condition for the boundability of our system under some condition. A necessary and sufficient condition for the boundability is also presented in terms of an inequality related to data rate and the minimum number of quantization intervals. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A new delay‐dependent stability criterion for time‐delay systems
Authors: Sun Jian , Liu G. P. 
Published: June 2009

AbstractThis paper is concerned with the problem of stability of time‐delay systems. A new type of augmented Lyapunov functional is proposed. By introducing some free‐weighting matrices and using the parameterized model transformation method, a new delay‐dependent stability condition is obtained in terms of a linear matrix inequality (LMI). Numerical examples are given to illustrate the effectiveness of the proposed methods. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Global sliding‐mode control with generalized sliding dynamics
Authors: Lu Yu‐Sheng , Chiu Chien‐Wei 
Published: June 2009

AbstractA global sliding‐mode control (GSMC) scheme is proposed to provide a framework for ensuring the existence of a sliding mode throughout an entire response. Based on this framework, robust eigenvalue‐assignment GSMC (REA‐GSMC) is proposed to robustly assign closed‐loop eigenvalues that must be real. The eigenvalues being all real, however, leads to sluggish responses. According to most error criteria such as IAE, ISE, and ITAE, the optimum system should have complex eigenvalues. This paper proposes a GSMC scheme with generalized sliding dynamics, referred to as Generalized GSMC, in order to release the previous constraint on the REA‐GSMC. Thus, the Generalized GSMC can be designed to achieve a system that is both robust and optimum in the sense that it minimizes certain error performance indices in spite of the presence of system uncertainties. Experiments were conducted on a two‐link direct‐drive manipulator to demonstrate the effectiveness of the proposed scheme. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
The impact of human superoxide dismutase 1 expression in a mouse model on the embryotoxicity of hydroxyurea
Authors: Larouche Geneviève , Hales Barbara F. 
Published: June 2009

AbstractBACKGROUND:Oxidative stress is hypothesized to mediate embryotoxicity during organogenesis, yet the reactive oxygen species involved are not defined. The superoxide oxygen radical is converted to hydrogen peroxide, a less reactive species, by superoxide dismutases (SODs). If superoxide is important in mediating embryotoxicity, increased SOD expression should protect embryos against insult. Exposure to hydroxyurea during organogenesis causes brain defects, cleft palate, tail anomalies, and limb defects; administration of D‐mannitol, a free radical scavenger, ameliorates hydroxyurea embryotoxicity, suggesting that oxidative stress is important. To elucidate the role of superoxide in mediating hydroxyurea embryotoxicity, we assessed the impact of human SOD1 expression in a murine model.METHODS:hSOD1 hemizygous male mice, carrying the human SOD1 gene, were mated to wild‐type or hSOD1 hemizygous females. Dams were treated on gestation day (GD) 9 with saline (control) or 400 (low) or 600 (high) mg/kg hydroxyurea (n = 8–13/group). Mice were euthanized on GD 18 and developmental toxicity was assessed.RESULTS:Exposure to hydroxyurea caused a dose‐dependent increase in fetal deaths that was not affected by hSOD1 expression; hydroxyurea decreased fetal weights in litters from wild‐type but not hemizygous dams. Hydroxyurea increased the incidence of external and skeletal malformations; fetuses from hemizygous dams treated with high‐dose hydroxyurea had fewer malformations compared to wild‐type dams. There was no correlation between embryonic phenotype and genotype or SOD activity.CONCLUSION:Maternal hSOD1 expression protected fetuses against malformations induced by hydroxyurea, providing evidence that superoxide plays a role in mediating the response of organogenesis stage embryos to this teratogen. Birth Defects Research (Part A) 2009. © 2009 Wiley‐Liss, Inc.
Lack of chick embryotoxicity after 20 kHz, 1.1 mT magnetic field exposure
Authors: Nishimura Izumi , Imai Setsuo , Negishi Tadashi 
Published: June 2009

AbstractThis investigation was undertaken because biological studies to evaluate the effects of intermediate frequency magnetic fields are insufficient. White Leghorn fertile eggs (60/group) were either exposed to a 20 kHz, 1.1 mT(rms) sinusoidal magnetic field or sham‐exposed during the first 2, 7, or 11 days of embryogenesis. Lower dose exposures at 0.011 and 0.11 mT(rms) for 2 days were also conducted to elucidate possible dose–response relationships. Additional eggs given all‐trans‐retinoic acid, a teratogen, were exposed to the 1.1 mT(rms) magnetic field for the same periods to investigate the modification of embryotoxicity. After exposure, embryos were examined for mortality and developmental abnormalities. Developmental stage, number of somite pairs, and other developmental endpoints were also evaluated. Experiments were triplicated and conducted in a blind fashion. No exposure‐related changes were found in any of the endpoints in intact embryos exposed to1.1 mT(rms) or to the lower doses of 0.11 and 0.011 mT(rms) magnetic fields. Retinoic acid administration produced embryotoxic responses, which were embryonic death and developmental abnormalities, in 40–60% of embryos in the sham‐exposed groups. The magnitude of these responses was not changed significantly by the magnetic field exposures. Under the present experimental conditions, exposure to 20 kHz magnetic field up to 1.1 mT(rms) was not embryotoxic in the chick and did not potentiate the embryotoxic action of retinoic acid. Bioelectromagnetics 30:573–582, 2009. © 2009 Wiley‐Liss, Inc.
A comprehensive kinetic model of laccase‐catalyzed oxidation of aqueous phenol
Authors: Kurniawati Selvia , Nicell James A. 
Published: June 2009

AbstractA comprehensive model was developed to describe the kinetics of the laccase‐catalyzed oxidation of phenol that incorporates enzyme kinetics, enzyme inactivation, variable reaction stoichiometry between substrate and oxygen, and oxygen mass‐transfer. The model was calibrated and validated against data obtained from experiments conducted in an open system, which allowed oxygen to transfer from air to the reacting mixture and phenol conversion to approach completion. Inactivation of laccase was observed over the course of the reaction and was found to be dependent on the rate of substrate transformation. A single kinetic expression was sufficient to describe laccase inactivation arising from interaction with reacting species over time. Excellent agreement was found between model predictions of phenol and oxygen concentrations and experimental data over time for a wide range of initial substrate concentrations and enzyme activities. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Assessment of physiological conditions in E. coli fermentations by epifluorescent microscopy and image analysis
Authors: Carneiro Sónia , Amaral António L. , Veloso Ana C. A. , Dias Teresa , Peres António M. , Ferreira Eugénio C. , Rocha Isabel 
Published: June 2009

AbstractThe development of monitoring methods for assessing the physiological state of microorganisms during recombinant fermentation processes has been encouraged by the need to evaluate the influence of processing conditions in recombinant protein production. In this work, a technique based on microscopy and image analysis was developed that allows the simultaneous quantification of parameters associated with viability and fluorescent protein production in recombinant Escherichia coli fermentations. Images obtained from light microscopy with phase contrast are used to assess the total number of cells in a given sample and, from epifluorescence microscopy, both protein producing and injured cells are evaluated using two different fluorochromes: propidium iodide and enhanced yellow fluorescent protein. This technique revealed the existence of different cell populations in the recombinant E. coli fermentation broth that were evaluated along four batch fermentations, complementing information obtained with standard techniques to study the effects of the temperature and induction time in recombinant protein production processes. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Reduced modeling and state observation of an activated sludge process
Authors: Queinnec Isabelle , Gómez‐Quintero Claudia‐Sophya 
Published: June 2009

AbstractThis article first proposes a reduction strategy of the activated sludge process model with alternated aeration. Initiated with the standard activated sludge model (ASM1), the reduction is based on some biochemical considerations followed by linear approximations of nonlinear terms. Two submodels are then obtained, one for the aerobic phase and one for the anoxic phase, using four state variables related to the organic substrate concentration, the ammonium and nitrate‐nitrite nitrogen, and the oxygen concentration. Then, a two‐step robust estimation strategy is used to estimate both the unmeasured state variables and the unknown inflow ammonium nitrogen concentration. Parameter uncertainty is considered in the dynamics and input matrices of the system. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Resolution of (±)‐β‐methylphenylethylamine by a novel chiral stationary phase for Pirkle‐type column chromatography
Authors: Yilmaz Hayrullah , Topal Giray , Cakmak Resit , Hosgoren Halil 
Published: June 2009

AbstractIn this study, a new Pirkle‐type chiral column stationary phase for resolution of β‐methylphenylethyl amine was described by using activated Sepharose 4B as a matrix, L‐tyrosine as a spacer arm, and an aromatic amine derivative of L‐glutamic acid as a ligand. The binding capacities of the stationary phase were determined at different pH values (pH = 6, 7, and 8) using buffer solutions as mobile phase, and enantiomeric excess (ee) was determined by HPLC equipped with chiral column. The ee was found to be 47%. Chirality, 2010. © 2009 Wiley‐Liss, Inc.