bluuebunny/crossref_metadata_2025_split huggingface dataset:
Normal and Lateral Deformation of Lyotropically Ordered Polymer Brush
Authors: Polotsky Alexey A. , Birshtein Tatiana M. 
Published: November 2006

AbstractSummary: Planar polymer brush formed by semirigid chains of freely jointed rigid segments and immersed into a solvent is considered. Brush collapse induced by deterioration of the solvent quality and its deformation by external normal or lateral force is studied. It is demonstrated that these three different situations can be described in the framework of the common approach. It is shown that the collapse is accompanied by liquid‐crystalline (LC) ordering within the brush. The LC transition can be jump‐like (the first order) or continuous, depending on the segment's aspect ratio and grafting density. Transition point is investigated in detail, the corresponding phase diagrams are calculated. It is shown that the phase diagrams of a normally deformed brush have different structures, with a narrow ‘leg’ in the good solvent region for sparsely grafted brush, with two coexistence regions and a triple point, in addition, for shorter segment length or without these features if the chains are densely grafted. For the laterally deformed brush, phase diagrams have similar structures with a critical point in the good solvent regime.Polymer brush subjected to deformation by normal (top) and lateral (bottom) external force.imagePolymer brush subjected to deformation by normal (top) and lateral (bottom) external force.
Effects of flavonoids on the expression of the pro‐inflammatory response in human monocytes induced by ligation of the receptor for AGEs
Authors: Huang Shang‐Ming , Wu Chi‐Hao , Yen Gow‐Chin 
Published: November 2006

AbstractIncreasing evidence has shown advanced glycation end products (AGEs) receptor ligation (RAGE) to be an important part of complex interactions of the oxidative stress and pro‐inflammatory responses. In this study, flavonoids were used to monitor the protective effects against the oxidative damage and inflammation mediated by AGEs in human monocytes. S100B (RAGE ligand) treatment in human THP‐1 monocytic cells (THP‐1) significantly increased gene expression of the pro‐inflammatory cytokines TNF‐α and IL‐1β; chemokines MCP‐1 and IP‐10; adhesion factors platelet endothelial cell adhesion molecule (PECAM‐1) and β2‐integrin; and pro‐inflammatory cyclooxygenase‐2 (COX‐2). S100B treatment with quercetin and catechin in THP‐1 cells had inhibitory effects on the expression of pro‐inflammatory genes and protein levels. Quercetin and catechin could regulate S100B‐activated oxidant stress‐sensitive pathways through blocking p47phox protein expression. Treatment with quercetin and catechin could eliminate reactive oxygen species (ROS) to reduce oxidative stress stimulated by S100B in THP‐1 cells. Quercetin and catechin also showed different regulatory abilities on mitogen‐activated protein kinase (MAPK) signaling pathways by inhibiting protein expression in S100B‐stimulated inflammatory responses in THP‐1 cells. This study suggests that quercetin and catechin may be of benefit for diabetic vascular complications due to its antioxidant abilities against AGE‐mediated oxidative stress through oxidative stress‐sensitive and oxidative stress‐responsive signaling pathways, which lead to inflammation in human monocytes.
In vitro fermentability of differently digested resistant starch preparations
Authors: Fässler Caroline , Arrigoni Eva , Venema Koen , Brouns Fred , Amadò Renato 
Published: November 2006

AbstractThe in vitro fermentability of two resistant starch preparations type 2 (RS2) and type 3 (RS3) was investigated using human colonic microbiota. Prior to the fermentation experiments, samples were digested using two in vitro models, a batch (ba) and a dynamic (dy), as well as an in vivo method (il) for RS3. Digestion residues were fermented in vitro using a simple batch model lasting 24 h and a more sophisticated dynamic model enduring 72 h. During batch fermentation, metabolite productions and starch degradation rates were similar for RS2 and RS3 but higher for dy‐ compared to ba‐digested samples. RS3il led to the lowest fermentability. Furthermore, increased butyrate ratios were observed for all preparations. The varying RS preparations behaved similarly in the dynamic fermentation but showed high SDs. Moreover, the fermentability was slow during the first 24 h, indicating that the microbiota needed an adaptation period to ferment RS. Propionate ratios increased at the expense of butyrate with exception for RS2dy showing an increase in acetate only. Differences in fermentability observed between the dynamic model, allowing a closer simulation of the in vivo behavior, and the batch model, recommended for screening purposes, could be due to the varying microbiota used.
Effect of lupeol and lupeol linoleate on lipemic – hepatocellular aberrations in rats fed a high cholesterol diet
Authors: Sudhahar Varatharajan , Ashokkumar Sekar , Varalakshmi Palaninathan 
Published: November 2006

AbstractCholesterol feeding has been often used to study the etiology of hypercholesterolaemia‐related metabolic disturbances. The aim of the present study is to investigate the effects of a pentacyclic triterpene, lupeol, and its ester derivative on hepatic abnormalities associated with hypercholesterolemic rats. Hypercholesterolaemia was induced in male Wistar rats by feeding them with a high cholesterol diet (HCD) containing normal rat chow supplemented with 4% cholesterol and 1% cholic acid, for 30 days. Lupeol and lupeol linoleate were supplemented (50 mg/kg body wt/day) during the last 15 days. Increased hepatic lipid profile along with abnormalities in lipid‐metabolizing enzyme activities were seen in hypercholesterolemic rats. An apparent increase in the expression of Acyl‐CoA cholesterol acyltransferase mRNA was seen in HCD fed rats. The activities of hepatic marker enzymes, which serve as indices of cellular injury, were altered in HCD fed rats. Treatment with triterpenes significantly modulated the abnormalities induced by hypercholesterolaemia. Also, an increased (P >0.001) faecal excretion of cholesterol and bile acids were observed in lupeol and lupeol linoleate group when compared with HCD fed group. Therefore, it can be concluded that triterpenes treatment afforded substantial protection against the anomalies, which are manifested during the early stage of hypercholesterolemic atherogenesis.
Analysis of sphingolipids in potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) by reversed phase high‐performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC‐ESI‐MS/MS)
Authors: Bartke Nana , Fischbeck Anne , Humpf Hans‐Ulrich 
Published: November 2006

AbstractCeramides and glucocerebrosides of potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas (L.) Lam.) were analyzed using RP‐HPLC‐ESI‐MS/MS. Ceramides and glucocerebrosides containing the three different long‐chain bases 4,8‐sphingadienine (d18:2Δ4,Δ8), 4‐hydroxy‐8‐sphingenine (t18:1Δ8), and 8‐sphingenine (d18:1Δ8) acylated to saturated and unsaturated hydroxy‐ and nonhydroxy fatty acids with 16–26 carbon atoms were detected. For ceramides and glucocerebrosides 4,8‐sphingadienine (d18:2Δ4,Δ8) was found as the major long‐chain base, with lesser amounts of 4‐hydroxy‐8‐sphingenine (t18:1Δ8) and 8‐sphingenine (d18:1Δ8). 2‐(α‐)Hydroxypalmitic acid (C16:0h) was the major fatty acid, which was found to be acylated to the long‐chain bases. For quantification of these compounds, an RP‐HPLC‐ESI‐MS/MS method with an “echo‐peak”‐technique simulating internal standard injection was developed. The analyzed samples of potatoes and sweet potatoes showed amounts of ˜0.1–8 μg/kg single ceramides and amounts up to 500 μg/kg glucocerebrosides, with C16:0h‐glucosyl‐4,8‐sphingadienine as the major component.
Robust fault estimation approach and its application in vehicle lateral dynamic systems
Authors: Gao Z. , Ding S. X. , Ma Y. 
Published: November 2006

AbstractFor state‐space systems with unknown process disturbances, a robust state‐space observer is designed to simultaneously estimate the system state, the finitely times derivatives of the fault, and the fault signal. The considered fault signal can be allowed to be unbounded provided its finitely times derivative is bounded. A numerical example is given to illustrate the design procedure. Vehicle lateral dynamic system plays an important role in the vehicle manoeuverability, stability and driving safety. An application example with the real data for the vehicle lateral dynamic system is finally provided to demonstrate the efficiency of the present estimation technique. Copyright © 2006 John Wiley & Sons, Ltd.
Current analytical methods to study plant water extracts: the example of two mushrooms species, Inonotus hispidus and Sparassis crispa
Authors: Politi Matteo , Silipo Alba , Siciliano Tiziana , Tebano Marianna , Flamini Guido , Braca Alessandra , Jiménez‐Barbero Jesús 
Published: November 2006

AbstractThe analytical study of two hot‐water extracts from the mushrooms Inonotus hispidus (Bull.) P. Karst and Sparassis crispa Wulf.:Fr was performed by NMR, HPLC‐PAD‐MS and GC‐MS. The simultaneous use of different analytical techniques highlighted the diverse classes of natural products contained in these extracts. This study describes an attempt to adapt a useful phytochemical method to the direct investigation of plant water extracts, which represent the typical traditional manner for the administration of natural remedies. The heritage concerning plant processing procedures, known as traditional pharmaceutical knowledge, could play an important role in future research on medicinal species. This kind of study could be used as an update for current and future perspectives in this research field. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of isoflavone glycosides in Pueraria lobata cultures by tandem mass spectrometry
Authors: Prasain Jeevan K. , Reppert Adam , Jones Kenneth , Moore II D. Ray , Barnes Stephen , Lila Mary Ann 
Published: November 2006

AbstractIsoflavones in the methanolic extracts of kudzu (Pueraria lobata) callus, suspension and root cultures were compared in order to develop an experimental system in which puerarin (daidzein 8‐C‐glucoside) and other isoflavones could be synthesised in vitro. Quantitative variation of puerarin and other known isoflavones was estimated in kudzu culture extracts using HPLC‐UV. The highest and lowest amounts of puerarin (14.56 and 0.33 mg/g) were present in in vitro root cultures and leaf tissue‐derived callus cultures, respectively. A total of 48 isoflavone metabolites were detected in extracts of kudzu root cultures by HPLC‐MS/MS, and the structures of 33 of them were tentatively assigned. Amongst these, 12 isoflavone C‐glycosides were identified. Hydroxy‐derivatives of puerarin in several isomeric forms were detected, some of which have not been previously reported in kudzu root. The molecular weights, interpretation of characteristic fragment ions obtained from HPLC‐MS/MS and comparison with reported data allowed the putative identification of the isoflavone metabolites. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation of polystyrene/polyaniline core/shell structured particles and their epoxy‐based conductive composites
Authors: Wang Yangyong , Jing Xinli 
Published: November 2006

AbstractPolyaniline (PANI) was synthesized by chemical oxidative polymerization of aniline (ANI) in the presence of sulfonated crosslinked polystyrene (SCPS) particles in neutral water. The polymerization of ANI occurred preferentially on the surfaces of the SCPS particles, resulting in core/shell structured SCPS/PANI particles. The conductivities of the SCPS/PANI particles increased with increasing degree of sulfonation of the SCPS and with increasing ANI/SCPS weight ratios in the reactants. Conductive epoxy‐based composites were prepared by curing the blend of SCPS/PANI particles and epoxy resin with an aromatic amine curing reagent, indicating the core/shell structured particles were stable, to some extent, to alkaline environments, which will be of significant importance for the practical application of PANI in many cases. Copyright © 2006 Society of Chemical Industry
Surface tension of poly(ester urethane)s and poly(ether urethane)s
Authors: Lupu Mihaela , Macocinschi Doina , Ioanid Ghiocel , Butnaru Maria , Ioan Silvia 
Published: November 2006

AbstractThe correlation between the surface tension parameters and the chemical composition of poly(ester urethane) and poly(ether urethane) thin films with different soft and hard segments, both before and after plasma treatment, was investigated. Calculations are based on the geometric mean approach of Owens and Wendt (Owens DK and Wendt RC, J Appl Polym Sci 13:1741 (1969)), Rabel (Rabel W, Physikalische Blätter 33:151 (1977)) and Kälble (Kälble DH, J Adhesion 1:102 (1969)), on the Lifshitz–van der Waals acid/base approach of van Oss and co‐workers (van Oss CJ, Good RJ and Chaudhury MK, Langmuir 4:884 (1988); van Oss CJ, Ju L, Chaudhury MK and Good RJ, Chem Rev 88:927 (1988); van Oss CJ, Interfacial Forces in Aqueous Media. Marcel Dekker, New York (1994)) and on the theoretical methods involving quantitative structure–property relationships (Bicerano J, JMS Rev Macromol Chem Phys C36:161 (1996)). For all investigated films, the polar terms contribute significantly to the total surface tensions, as due to the large electron donor, $\gamma_{\rm {sv}}^{-}$, interactions. Plasma treatment alters the surface energy of samples by changing their surface polarity and hydrophilicity. The hydrophilicity trends for polyurethanes were also studied by means of the free energy of hydration between compounds and water. Preliminary blood contact tests of the selected polyurethane sample with higher hydrophilicity were developed for biomedical applications. Copyright © 2006 Society of Chemical Industry
Dimensionally and thermally stable polymer, containing disordered graphitic structure and adamantane
Authors: Burnham Kikue S. , Roth Robert , Zhou Faith , Fan Wenya , Brouk Emma , Stifanos Mehari 
Published: November 2006

AbstractIn an attempt to develop a low‐k interlayer dielectric, adamantane‐diphenyldiethynyl moiety containing oligomer is prepared. Oligomerization of 1,3,5,7‐tetrakis[3/4‐ethynylphenyl]adamantane (4) is accomplished by a Glaser–Hay oxidative coupling with 1,3,5‐triethynylbenzene and phenylacetylene end‐capping agent. The CHCl3 soluble oligomer is then thermally treated by step‐curing at 200, 300, 380, and 450 °C for 30 min at each temperature under nitrogen flow to render a shiny void‐free black polymer. TGA analysis indicates that the polymer is stable under nitrogen up to 500 °C with a marginal decomposition up to 800 °C. Solid‐state 13C NMR, Raman scattering, and FTIR are used to characterize the structure of the polymer. The polymer consists of amorphous carbon networks with the adamantane moieties and nanosized graphitic regions (clusters), which are generated from the thermal crosslinking of the diphenyldiethynyl units. It shows a remarkably low linear coefficient of thermal expansion (∼25 ppm/°C), presumably due to the presence of the disordered graphitic structure. Its high density (∼1.21 g/cm3), refractive index (∼1.80 at 632 nm), and Young's modulus (∼17.0 GPa) are also consistent with the interpretation. This study reveals important details about the effect of microscopic structure on the macroscopic properties of the highly crosslinked polymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6909–6925, 2006
Copolymerizations of ethylene and polar comonomers with bis(phenoxyketimine) group IV complexes: Effects of the central metal properties
Authors: Zhang Xiaofan , Chen Shangtao , Li Huayi , Zhang Zhicheng , Lu Yingying , Wu Chunhong , Hu Youliang 
Published: November 2006

AbstractWith triisobutylaluminum as a protection reagent, copolymerizations of ethylene with 10‐undecen‐1‐ol, 10‐undecenoic acid, and 5‐hexen‐1‐ol have been performed with bis[(3,5‐di‐tBuC6H22‐O)PhCN(2‐FC6H4)]ZrCl2 (a)/methylaluminoxane or bis[(3,5‐di‐tBuC6H22‐O)PhCN(2‐FC6H4)]TiCl2 (b)/methylaluminoxane as the catalyst. Both catalysts exhibit high activities of copolymerization in the presence of polar groups. The properties of the copolymers are strongly affected by the central metal properties of the catalysts. In comparison with complex a, titanium complex b appears to be less sensitive to polar monomers and more favorable for the preparation of higher molecular weight functionalized polyethylenes containing higher contents of polar groups. Studies on the polymerization temperature indicate that the catalytic activities decrease greatly with both complex a and complex b. The comonomer contents incorporated into the copolymers are slightly dependent on the polymerization temperature in the case of complex a, whereas in the case of complex b, the effect of the polymerization temperature is more distinct: an increase in the polymerization temperature can efficiently facilitate the incorporation of polar comonomers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 59–68, 2007
Poly(ethylene glycol)‐b‐phosphorylated polyglycidols as CaCO3 crystal growth modifiers. II. Macromolecular architecture versus the crystal size and shape and crystallization inhibition
Authors: Kaluzynski K. , Pretula J. , Penczek S. 
Published: November 2006

AbstractIonic–nonionic dihydrophilic block copolymers with poly(ethylene glycol) as nonionic blocks and phosphorylated polyglycidol as ionic blocks of various lengths and various degrees of phosphorylation were prepared. The influence of these variables on the CaCO3 crystal structure and the inhibition of crystal growth was studied. The best results (small crystal size, low dispersity of sizes, and longest inhibition time) were observed for limited degrees of phosphorylation. A certain part of the dihydrophilic block copolymers was permanently bound to the formed particles, opening a way to the synthesis of inorganic–organic (polymer) hybrids based on these components. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 90–98, 2007
Similarities between polyelectrolyte gels and biopolymer solutions
Authors: Horkay Ferenc , Hecht Anne‐Marie , Geissler Erik 
Published: November 2006

AbstractSmall angle neutron scattering (SANS) measurements and osmotic swelling pressure measurements are reported for polyelectrolyte gels and solutions under nearly physiological conditions. A synthetic polymer (sodium‐polyacrylate) and three biopolymers (DNA, hyaluronic acid, and polyaspartic acid) are studied. The neutron scattering response of these anionic polyelectrolytes is closely similar, indicating that at larger length scales the organization of the polymer molecules is not significantly affected by the fine details of the molecular architecture (e.g., size and chemical structure of the monomer unit, type of polymer backbone). The results suggest that specific interactions between the polyelectrolyte chains and the surrounding monovalent cations are negligible. It is found that the osmotic compression modulus of these biopolymer solutions determined from the analysis of the SANS response decreases with increasing chain persistence length. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3679–3686, 2006
Phase equilibria and phase separation dynamics in a polymer composite containing a main‐chain liquid crystalline polymer
Authors: Kim Do , Kyu Thein , Hashimoto Takeji 
Published: November 2006

AbstractVarious topological phase diagrams of blends of main‐chain liquid crystalline polymer (MCLCP) and flexible polymer have been established theoretically in the framework of Matsuyama–Kato theory by combining Flory–Huggins (FH) free energy for isotropic mixing, Maier–Saupe (MS) free energy for nematic ordering in the constituent MCLCP, and free energy pertaining to polymer chain‐rigidity. As a scouting study, various phase diagrams of binary flexible polymer blends have been solved self‐consistently that reveal a combined lower critical solution temperature (LCST) and upper critical solution temperature (UCST), including an hourglass phase diagram. The calculated phase diagrams exhibit liquidus and solidus lines along with a nematic–isotropic (NI) transition of the constituent MCLCP. Depending on the strengths of the FH interaction parameters and the anisotropic (nematic–nematic) interaction parameters, the self‐consistent solution reveals an hourglass type phase diagram overlapping with the NI transition of the constituent MCLCP. Subsequently, thermodynamic parameters estimated from the phase diagrams hitherto established have been employed in the numerical computation to elucidate phase separation dynamics and morphology evolution accompanying thermal‐quench induced phase separation of the MCLCP/polymer mixture. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3621‐3630, 2006
Production of an Atmospheric‐Pressure Glow Discharge Using an Inductive Energy Storage Pulsed Power Generator
Authors: Takaki Koichi , Kirihara Hidekazu , Noda Chiharu , Mukaigawa Seiji , Fujiwara Tamiya 
Published: November 2006

AbstractSummary: An atmospheric‐pressure glow discharge has been generated using an inductive energy storage pulsed power generator. A pulsed high voltage with a short rise time of under 30 ns is employed to generate streamer discharges simultaneously at all tips of a needle‐array electrode in nitrogen. The large number of streamer discharges prevent glow‐to‐arc transitions caused by inhomogeneous thermalization. SOS diodes are used as an opening switch to shorten the rise time. Circuit parameters such as the capacitance of a primary energy storage capacitor and/or the inductance of a secondary energy storage inductor are determined by experimental results using dummy resistive loads. The results show that circuit parameters adequate for producing atmospheric glow discharges are different from those for producing corona discharges. The energy transfer efficiency of the pulsed power generator has a maximum value of 75% at 193 Ω dummy load resistance. Voltage‐current characteristics of the glow discharge show two regions: constant voltage (normal glow) and an increasing voltage with discharge current (abnormal glow). The glow current is drastically decreased by eliminating the SOS diodes, in which case the charging voltage is directly applied to the electrode. Spatial‐ and time‐averaged electron densities in a positive column are estimated from calculations based on nitrogen swarm data. The electron density is estimated to be 1.8 × 1011 cm−3, which is much larger than 9.7 × 109 cm−3 in the case without the SOS diodes.Photographs of atmospheric pressure nitrogen glow discharge generated using a needle‐array electrode at a 1.0 cm gap length.imagePhotographs of atmospheric pressure nitrogen glow discharge generated using a needle‐array electrode at a 1.0 cm gap length.