bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical studies of the interaction of time‐modulated multi‐gigabit sequences with metamaterial structures at millimeter‐wave frequencies
Authors: Franson Steven J. , Ziolkowski Richard W. 
Published: March 2006

AbstractIt is shown with time domain simulations using the finite integration technique (FIT) that a metamaterial that acts as an artificial magnetic conductor (AMC), i.e. a metamaterial which produces an in‐phase reflection, exhibits a time delay before its intended response can occur. A millimeter‐wave metamaterial AMC is obtained as a generalization of a successfully designed microwave frequency AMC block consisting of an array of capacitively loaded loops (CLLs). It is also shown that while this time delay does distort millimeter‐wave frequency signals composed of time‐modulated multi‐gigabit sequences, it does not have a detrimental impact on the overall system performance when these multi‐gigabit/s signals interact with this CLL‐based AMC. This time delay behaviour is demonstrated for several different but common communication‐based modulation schemes. The presence of peculiar spikes in the output waveforms is tied to the time domain behaviour of the currents on the CLLs in the metamaterial AMC. Copyright © 2006 John Wiley & Sons, Ltd.
Off‐normal incidence simulations of metamaterials using FDTD
Authors: Schurig D. 
Published: March 2006

AbstractA method is described for applying FDTD simulation to electromagnetic metamaterial slabs with off‐normal incident plane wave radiation. Issues of incommensurate spatial periods and interpolation of irregularly spaced data are discussed. Validity of the method is tested on a dielectric slab with known analytical solutions and the method is used to analyse split ring resonators of current interest. Copyright © 2006 John Wiley & Sons, Ltd.
Impact of South Pacific circulation variability on east African rainfall
Authors: McHugh Maurice J. 
Published: March 2006

AbstractWhile examining the atmospheric structure and dynamics through which the El Niño‐Southern Oscillation phenomenon is associated with east African rainfall, it was discovered that circulation variability in the subtropical South Pacific Ocean has a significant but seasonally varying influence on east African rainfall receipt on interannual timescales. Enhanced equatorial east African rainfall receipt associated with El Niño events is well known to occur during the long rains from October to December, but rainfall deficits during the same season are typical of La Niña events. South Pacific circulation variability is found to enhance rainfall receipt during the October to December period, but is associated with significant east African rainfall deficits during the March to May rainy period. It is demonstrated here that outbreaks of moist South Atlantic westerly flows that are often associated with anomalous rainfall receipt over east Africa are enhanced (weakened) during El Niño (La Niña) periods.An empirical orthogonal function analysis is performed to extract the principal mode of sea level pressure variability in the tropical and subtropical South Pacific region. The time series associated with the principal mode of South Pacific circulation variability is correlated with circulation, atmospheric humidity, and outgoing longwave radiation fields during the short rains (October–December) and long rains (March–May). It is shown that South Pacific circulation variability is positively associated with east African rainfall receipt (r = 0.42, significant at the 99% confidence interval). Strengthened inflows of moist South Atlantic westerlies are associated with enhanced low‐level moisture convergence, decreased lower tropospheric stability, increased cloudiness, and increased precipitable water anomalies observed during OND. Reverse circulation and hydroclimatic anomalies observed during MAM are consistent with a negative association with east African rainfall during that season; r = −0.33, significant at the 98% confidence interval.The temporal stability of these associations was tested during periods in which the principal interannual signal associated with El Niño was either very strong or very weak, and it was demonstrated that the correlations strengthened slightly (weakened markedly) during the period when the 5‐year signal was very strong (weak). Copyright © 2006 Royal Meteorological Society
Effects of a glycoconjugate from Lycium barbarum on body composition in growing mice
Authors: Zhang Min , Chen Haixia 
Published: March 2006

AbstractThis study investigated the effect of a kind of glycoconjugate from Lycium barbarum (GLB) on body composition in growing mice. The composition of GLB was determined; the body weight, food conversion rate, visceral index, fat index and mineral concentration in bone and muscle of mice were assessed. The health of the mice was evaluated in a swimming endurance test. The results showed that the contents of neutral sugar, uronic acid, protein and mineral in GLB were (mg g−1): 287.8, 494.5, 56.3 and 161, respectively. GLB fed at rates of 5 mg kg−1 d−1, 10 mg kg−1 d−1 and 20 mg kg−1 d−1 could reduce the growth rate of body weight, food conversion rate and the subcutaneous fat of mice. The swimming time of the growing mice was increased by GLB treatment. GLB induced an increase in thymus index and a decrease in spleen index. GLB had significant effects on the concentration of Zn and Fe in shank (p < 0.01) and could elevate the concentration of Ca and Zn in haunch muscle. The results showed that GLB was helpful to the development of mice. Copyright © 2006 Society of Chemical Industry
Ripening‐related changes in the cell walls of olive (Olea europaea L.) pulp of two consecutive harvests
Authors: Mafra Isabel , Barros António S , Nunes Cláudia , Vitorino Rui , Saraiva Jorge , Smith Andrew C , Waldron Keith W , Delgadillo Ivonne , Coimbra Manuel A 
Published: March 2006

AbstractOlive fruits, harvested in two consecutive seasons at green, cherry and black stages, were used to study compositional changes in the cell walls during ripening. Ripening‐related changes in both harvests were characterised mainly by an increase in the solubilisation of pectic and hemicellulosic polysaccharides, an increase in the relative amount of arabinose in pectic polysaccharides and a decrease in the degree of methylesterification of pectic polysaccharides. Further to degrading processes, the data obtained suggest the synthesis of new polysaccharides. The analysis of olive cell wall phenolics showed mainly the presence of p‐coumaric acid, which increased in one harvest, whereas in the other the values did not differ. The samples of the second harvest, although presenting green, cherry and black colours, had less distinct ripening characteristics than those of the previous harvest. Different activity levels of polyphenol oxidase, polygalacturonase and pectin methylesterase might have contributed to the differences observed between the two harvests. The results showed the distinct extension of ripening‐related changes in the cell walls of the two harvests, indicating that the olive colour, although characteristic of the stage of ripening, cannot be strictly used for its evaluation and definition. Copyright © 2006 Society of Chemical Industry
Green Polymers from Geobacillus thermodenitrificans DSM465 – Candidates for Molecularly Imprinted Materials
Authors: Yoshikawa Masakazu , Kawamura Kensuke , Ejima Akinori , Aoki Takashi , Sakurai Shinichi , Hayashi Kyoko , Watanabe Kunihiko 
Published: March 2006

AbstractSummary: Novel molecular recognition materials were prepared from water soluble proteins from thermophile G. thermodenitrificans DSM465 by an alternative molecular imprinting method. Water soluble proteins from G. thermodenitrificans DSM465 were converted into the molecularly imprinted materials by adopting 9‐EA as a print molecule. The molecularly imprinted protein membranes recognized As in preference to Gs. The adsorption isotherms led to the conclusion that molecular recognition sites toward As were constructed by the presence of 9‐EA during the membrane preparation process. The affinity constant between As and the molecular recognition site thus constructed was determined to be 1.75 × 105 mol−1 dm3. The results obtained in the present study suggest that water soluble proteins from G. thermodenitrificans DSM465 is one of environmentally‐friendly ‘green’ polymers to be converted into molecular recognition materials by applying an alternative molecular imprinting method.Adsorption isotherms of As and Gs in the 9‐EA molecularly imprinted protein and the control non‐imprinted membranes. (a): As in the 9‐EA molecularly imprinted membrane. (b): Gs in the 9‐EA molecularly imprinted membrane. (c): As in the control non‐imprinted membrane. (d): Gs in the control non‐imprinted membrane.magnified imageAdsorption isotherms of As and Gs in the 9‐EA molecularly imprinted protein and the control non‐imprinted membranes. (a): As in the 9‐EA molecularly imprinted membrane. (b): Gs in the 9‐EA molecularly imprinted membrane. (c): As in the control non‐imprinted membrane. (d): Gs in the control non‐imprinted membrane.
Tailored Synthesis and Fundamental Characterization of Organic‐Inorganic Hybrid Gels by Means of a Hydrosilylation Reaction
Authors: Naga Naofumi , Oda Emiko , Toyota Akinori , Horie Kazuyuki , Furukawa Hidemitsu 
Published: March 2006

AbstractSummary: Organic‐inorganic hybrid gels have been synthesized from siloxane, 1,3,5,7‐tetramethylcyclotetrasiloxane (TMCTS), tetrakis(dimethylsilyloxy)silane (TDSS) or silsesquioxane, 1,3,5,7,9,11,13,15‐octakis(dimethylsilyloxy)pentacyclo‐[9,5,1,1,1,1]octasilsesquioxane (POSS), as crosslinking reagents and α,ω‐nonconjugated dienes, 1,5‐hexadiene (HD), 1,7‐octadiene (OD) and 1,9‐decadiene (DD), using a hydrosilylation reaction with a Pt catalyst. The network structures of the resulting gels were investigated by means of a novel scanning microscopic light scattering system. The structures of the crosslinking reagent and the length of the α,ω‐non‐conjugated dienes strongly affected the formation and network structures of the resulting gels. The critical gel concentration decreased when the molecular length of the non‐conjugated diene used was increased. The structures and SiH group numbers of the crosslinking reagents affected the critical gel concentration, and its values decreased in the following order: TDSS > TMCTS > POSS. The mesh size distribution in the network structure was quantitatively characterized using the light scattering system and almost presupposed sizes with quite narrow size distributions were attained in the gels from TMCTS‐HD, OD systems and TDSS‐OD systems. On the other hand, the gels derived from POSS or DD showed larger mesh sizes than expected.
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Melt Mixing of Polycarbonate with Multi‐Walled Carbon Nanotubes in Miniature Mixers
Authors: Lin Bin , Sundararaj Uttandaraman , Pötschke Petra 
Published: March 2006

AbstractSummary: MWNT mixtures with PC were prepared in three different miniature mixers at 265 °C and 50 rpm for 6 min by the master batch dilution method. One mixer is a 4.5 cm3 DACA microcompounder (DACA Instruments) consisting of two conical co‐rotating screws with a bypass, allowing the material to circulate for defined periods. The other two miniature mixers are custom‐built in our lab: the 2.2 cm3 APAM and the 3 cm3 MBM. The volume resistivity for the nanocomposites obtained from the APAM and the MBM showed a similar trend for different MWNT compositions. The electrical percolation concentration for the nanocomposites prepared in the APAM and the MBM is between 0.50 wt.‐% (or 0.34 vol.‐%) and 0.75 wt.‐% (or 0.52 vol.‐%) MWNT, and it is between 0.75 wt.‐% (or 0.52 vol.‐%) and 1.00 wt.‐% (or 0.69 vol.‐%) for the DACA microcompounder. Rheological characterization indicates that the microstructure of PC/MWNT composites prepared from the miniature mixers changes at a concentration of 0.38 wt.‐% for the APAM and the MBM and 0.50 wt.‐% for the DACA where an interconnected network is formed. TEM micrographs show that there are some small aggregates in the nanocomposites obtained from the APAM, fewer aggregates from the MBM, and least from the DACA. AFM analysis suggests that the length of nanotubes is reduced from 0.57 µm to 0.38–0.42 µm after they were melt mixed in the three mixers.Effect of MWNT content on volume resistivity of PC/MWNT obtained from different microcompounders.magnified imageEffect of MWNT content on volume resistivity of PC/MWNT obtained from different microcompounders.
Indentation Fracture Mechanics for Toughness Assessment of PMMA/SiO2 Nanocomposites
Authors: Lach Ralf , Kim Gyeong‐Man , Michler Goerg Hannes , Grellmann Wolfgang , Albrecht Klaus 
Published: March 2006

AbstractSummary: Based on the results from agglomerate‐free PMMA nanocomposites with 10 and 20 wt.‐% spherical SiO2 nanoparticles, it has been shown that indentation fracture mechanics is a straightforward, powerful, cost‐effective and time‐effective tool for analyzing the fracture resistance of novel polymer materials, such as brittle nanostructured polymer‐ceramic hybrids. In contrast to pure PMMA, the R‐curve effect, i.e., the enhancement in crack resistance as a function of crack size, was not observed in the nanocomposites investigated. Fracture toughness was found to depend on the SiO2 nanoparticle content, and the maximum value was observed at 10 wt.‐%. A significant reduction in fracture toughness occurred at 20 wt.‐% SiO2 nanoparticles, which is associated with a percolation of the bound layers (interfacial layers) around the SiO2 particles. From DSC data, the thickness of the interfacial polymer layer was estimated to be about 9 nm.Hardness, elastic modulus and fracture toughness of PMMA/SiO2 composites as a function of nanoparticle fraction.magnified imageHardness, elastic modulus and fracture toughness of PMMA/SiO2 composites as a function of nanoparticle fraction.
Ethylene and Propylene Polymerization Using In Situ Supported Me2Si(Ind)2ZrCl2 Catalyst: Experimental and Theoretical Study
Authors: Franceschini Fernando C. , da R. Tavares Tatiana T. , dos Santos João H. Z. , Ferreira Maria L. , Soares João B. P. 
Published: March 2006

AbstractSummary: Me2Si(Ind)2ZrCl2 was in situ immobilized onto SMAO and used for ethylene and propylene polymerization in the presence of TEA or TIBA as cocatalyst. The catalytic system Me2Si(Ind)2ZrCl2/SMAO exhibited different behavior depending on the amount and nature of the alkylaluminum employed and on the monomer type. The catalyst activity was nearly 0.4 kg polymer · g cat−1 · h−1 with both cocatalysts for propylene polymerization. Similar activities were observed for ethylene polymerization in the presence of TIBA. When ethylene was polymerized using TEA at an Al/Zr molar ratio of 250, the activity was 10 times higher. Polyethylenes made by in situ supported or homogeneous catalyst systems had practically the same melting point (Tm). On the other hand, poly(propylenes) made using in situ supported catalyst systems had a slightly lower Tm than poly(propylenes) made using homogeneous catalyst systems. The nature and amount of the alkylaluminum also influenced the molar mass. The poly(propylene) molar mass was higher when TIBA was the cocatalyst. The opposite behavior was observed for the polyethylenes. Concerning the alkylaluminum concentration, the molar mass of the polymers decreased as the amount of TEA increased. In the presence of TIBA, the polyethylene's molar mass was almost the same, independent of the alkylaluminum concentration, and the poly(propylene) molar mass increased with increasing amounts of cocatalyst. The deconvolution of the GPC curves showed 2 peaks for the homogeneous system and 3 peaks for the heterogeneous in situ supported system. The only exception was observed when TEA was used at an Al/Zr molar ratio of 500, where the best fit was obtained with 2 peaks. Based on the GPC deconvolution results and on the theoretical modeling, a proposal for the active site structure was made.Molar mass distribution deconvolution of polyethylene prepared with the system Me2Si(Ind)2ZrCl2/SMAO/TIBA with 500 mol/mol of alkylaluminum as cocatalyst.magnified imageMolar mass distribution deconvolution of polyethylene prepared with the system Me2Si(Ind)2ZrCl2/SMAO/TIBA with 500 mol/mol of alkylaluminum as cocatalyst.
Combining In‐Situ Organic Modification of Montmorillonite and the Latex Compounding Method to Prepare High‐Performance Rubber‐Montmorillonite Nanocomposites
Authors: Jia Qing‐Xiu , Wu You‐Ping , Xu Yan‐Li , Mao Hui‐Hui , Zhang Li‐Qun 
Published: March 2006

AbstractSummary: To improve the interfacial interaction in MMT‐SBR nanocomposites, one type of UOAC was introduced to in‐situ modified MMT before latex compounding with SBR. The influence of the UOAC/MMT ratio on the structure and properties of MMT/SBR nanocomposites were carefully studied by XRD, TEM, and mechanical testing. It was found that through the in‐situ organic modification, a rubber‐intercalated structure of MMT was obtained in the nanocomposites, and the amount of rubber‐intercalated structure strongly depended on the UOAC/MMT ratio. The tensile strength of MMT‐SBR nanocomposites was enhanced dramatically from 4 to 18 MPa by in‐situ organic modification of MMT.Stress‐strain diagram of SBR/clay nanocomposites.magnified imageStress‐strain diagram of SBR/clay nanocomposites.
Development and Characterization of Novel Biomimetic Composite Scaffolds Based on Bioglass‐Collagen‐Hyaluronic Acid‐Phosphatidylserine for Tissue Engineering Applications
Authors: Wang Yingjun , Yang Chunrong , Chen Xiaofeng , Zhao Naru 
Published: March 2006

AbstractSummary: Biomimetic scaffolds are appealing products for the repair of bone defects using tissue engineering strategies. The present study prepared novel biomimetic composite scaffolds with similar composite to natural bone using bioactive glass, collagen, hyaluronic acid, and phosphatidylserine. The microstructure, swelling ratio, biodegradability, and biomineralization characteristic of the composite scaffolds with and without hyaluronic acid and phosphatidylserine were compared and analyzed by SEM/EDAX, XRD, and FTIR techniques and in vitro test, and the properties can be influenced by 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC)/N‐hydroxysuccinimide (NHS) crosslinking. The optimized properties of the crosslinked composite scaffolds observed in this study show the possibility of their use of bioactive and bioresorbable scaffolds in bone tissue engineering.SEM micrographs of BG‐COL‐HYA‐PS composite scaffolds after immersion in SBF for 1 d.magnified imageSEM micrographs of BG‐COL‐HYA‐PS composite scaffolds after immersion in SBF for 1 d.
Nanogel‐Templated Mineralization: Polymer‐Calcium Phosphate Hybrid Nanomaterials
Authors: Sugawara Ayae , Yamane Setsuko , Akiyoshi Kazunari 
Published: March 2006

AbstractSummary: We report novel organic‐inorganic hybrid nanomaterials that consist of polymer hydrogel nanoparticles (nanogels) and calcium phosphate. Hybrid nanoparticles that measure ca. 40 nm are synthesized from a dilute solution of hydroxyapatite using nanogels as templates for calcium phosphate mineralization. These nanoparticles show a narrow size distribution and high colloidal stability. Nanogel‐adsorbed liposomes act as templates for hierarchical hybrid nanostructures. These nanohybrids can potentially be used as biocompatible drug carriers with controlled‐release properties.TEM images of calcium phosphate nanoparticles formed in the presence of CHP nanogels (0.5 mg · mL−1) (left) and nanogel‐liposomes (CHP 0.05 mg · mL−1, DPPC 0.08 mg · mL−1)(right).magnified imageTEM images of calcium phosphate nanoparticles formed in the presence of CHP nanogels (0.5 mg · mL−1) (left) and nanogel‐liposomes (CHP 0.05 mg · mL−1, DPPC 0.08 mg · mL−1)(right).
Preparation and Characterization of Polypyrrole/TiO2 Coaxial Nanocables
Authors: Lu Xiaofeng , Zhao Qidong , Liu Xincai , Wang Dejun , Zhang Wanjin , Wang Ce , Wei Yen 
Published: March 2006

AbstractSummary: We demonstrate in this communication that large‐scale coaxial nanocables of polypyrrole (PPy)/TiO2 can be obtained via three steps: (1) synthesis of TiO2 nanofibers by electrospinning; (2) physical adsorption Fe3+ oxidant on the surface of TiO2 nanofibers; (3) followed by polymerization of pyrrole (from vapor) on the surface of TiO2 nanofibers. During the synthesis, the PPy formed on TiO2 nanofibers as a template and formed PPy/TiO2 coaxial nanocables. TEM image proved that PPy (20 nm thickness) covered the surface of TiO2 nanofibers. Fourier‐transform infrared (FTIR), X‐ray photoelectron spectra (XPS), and X‐ray diffraction patterns (XRD) characterized the chemical structure of the coaxial nanocables. Surface photovoltage spectroscopy (SPS) revealed the surface properties of the PPy/TiO2 coaxial nanocables.TEM image of individual PPy/TiO2 coaxial nanocable.magnified imageTEM image of individual PPy/TiO2 coaxial nanocable.
Cooperative Self‐Assembly of Nanoparticle Mixtures in Lamellar Diblock Copolymers: A Dissipative Particle Dynamics Study
Authors: Liu Dahuan , Zhong Chongli 
Published: March 2006

AbstractSummary: Dissipative particle dynamics simulations are performed on the distribution of binary nanoparticle mixtures in lamellar diblock copolymers. The results show that the self‐assembly of nanoparticle mixtures in polymer matrix is a cooperative assembly that is affected by various factors, providing molecular‐level information for the rational design of new polymer nanocomposites with tailored properties.The simulated polymer nanocomposite structure (the polymer matrix was omitted for clarity; P, gray; Q, black).magnified imageThe simulated polymer nanocomposite structure (the polymer matrix was omitted for clarity; P, gray; Q, black).
Quantification of atherosclerotic plaque components using in vivo MRI and supervised classifiers
Authors: Hofman J.M.A. , Branderhorst W.J. , ten Eikelder H.M.M. , Cappendijk V.C. , Heeneman S. , Kooi M.E. , Hilbers P.A.J. , ter Haar Romeny B.M. 
Published: March 2006

AbstractIn this work we aimed to study the possibility of using supervised classifiers to quantify the main components of carotid atherosclerotic plaque in vivo on the basis of multisequence MRI data. MRI data consisting of five MR weightings were obtained from 25 symptomatic subjects. Histological micrographs of endarterectomy specimens from the 25 carotids were used as a standard of reference for training and evaluation. The set of subjects was divided in a training set (12 subjects) and an evaluation set (13 subjects). Four different classifiers and two human MRI readers determined the percentages of calcified tissue, fibrous tissue, lipid core, and intraplaque hemorrhage on the subject level for all subjects in the evaluation set. Quantification of the relatively small amounts of calcium could not be done with statistical significance by either the classifiers or the MRI readers. For the other tissues a simple Bayesian classifier (Bayes) performed better than the other classifiers and the MRI readers. All classifiers performed better than the MRI readers in quantifying the sum of hemorrhage and lipid proportions. The MRI readers overestimated the hemorrhage proportions and tended to underestimate the lipid proportions. In conclusion, this pilot study demonstrates the benefits of algorithmic classifiers for quantifying plaque components. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.