bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability improvement in power systems with non‐linear TCSC control strategies
Authors: Lei X. , Jiang D. , Retzmann D. 
Published: July 2010

AbstractIn this paper, a non‐linear control scheme for the TCSC (thyristor‐controlled series compensator) to dampen power oscillations and to improve the transient stability of power systems is presented. Based on an one‐machine‐infinite‐bus system, a non‐linear mathematical model is established which is proven as an affine nonlinear system. With the help of the feedback linearization technique, the affine non‐linear model is exactly transferred to a linear model, and then the control scheme is designed for the TCSC based on the global linearization, where the input signal uses local measurements only. The effectiveness and robustness of the proposed non‐linear control scheme are demonstrated with an one‐machine test system, where the TCSC modelling and power system simulations are performed by using the program system NETOMAC. In comparison with a conventional control scheme, significant improvements of dynamical performance in the test power' system are achieved by the proposed non‐linear control strategy for the TCSC.
Digital implementation of fuzzy control algorithm for shunt active filter
Authors: Singh B. N. , Singh B. , Chandra A. , Al‐Haddad K. 
Published: July 2010

AbstractThe paper deals with a digital‐signal‐processor (DSP)‐based implementation of a Fuzzy control algorithm for a three‐phase active filter (AF). The laboratory prototype model of the AF uses voltage source inverter (VSl) with pulse‐width modulation (PWM) current control technique. The AF is employed to compensate harmonics and reactive power of a non‐linear load. A three‐phase diode bridge rectifier with resistive‐inductive load is taken as a non‐linear load. With a view to obtain the steady‐state and transient response of the AF system, its mathematical model is developed. Experimental verification of simulated results is carried out to validate the proposed fuzzy control technique for AF systems.
One‐pot synthesis of surface‐functionalized molecularly imprinted polymer microspheres by iniferter‐induced “living” radical precipitation polymerization
Authors: Li Junyi , Zu Baiyi , Zhang Ying , Guo Xianzhi , Zhang Huiqi 
Published: July 2010

AbstractThis article describes for the first time the development of a new polymerization technique by introducing iniferter‐induced “living” radical polymerization mechanism into precipitation polymerization and its application in the molecular imprinting field. The resulting iniferter‐induced “living” radical precipitation polymerization (ILRPP) has proven to be an effective approach for generating not only narrow disperse poly(ethylene glycol dimethacrylate) microspheres but also molecularly imprinted polymer (MIP) microspheres with obvious molecular imprinting effects towards the template (a herbicide 2,4‐dichlorophenoxyacetic acid (2,4‐D)), rather fast template rebinding kinetics, and appreciable selectivity over structurally related compounds. The binding association constant Ka and apparent maximum number Nmax for the high‐affinity sites of the 2,4‐D imprinted polymer were determined by Scatchard analysis and found to be 1.18 × 104 M−1 and 4.37 μmol/g, respectively. In addition, the general applicability of ILRPP in molecular imprinting was also confirmed by the successful preparation of MIP microspheres with another template (2‐chloromandelic acid). In particular, the living nature of ILRPP makes it highly useful for the facile one‐pot synthesis of functional polymer/MIP microspheres with surface‐bound iniferter groups, which allows their direct controlled surface modification via surface‐initiated iniferter polymerization and is thus of great potential in preparing advanced polymer/MIP materials. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3217–3228, 2010
Synthesis of amphiphilic A3B mikto‐arm copolymers from a sugar core: Combination of hydrophobic PCL and hydrophilic glycopolymers for biocompatible nanovector preparation
Authors: Suriano Fabian , Coulembier Olivier , Dubois Philippe 
Published: July 2010

AbstractAmphiphilic A3B mikto‐arm copolymers have been synthesized using a t‐butyl‐diphenyl silyl‐based methylglucoside derivative. The latter has been first used as initiator for the polymerization of ε‐caprolactone leading to three‐arm star‐shaped structures followed by several postpolymerization steps to obtain star‐shaped poly(ε‐caprolactone) macroinitiator. Atom transfer radical polymerization (ATRP) of diisopropylidene galactose methacrylate in THF at 60 °C using CuBr ligated with 1,1,4,7,10,10‐hexamethyltriethylenetetramine (HMTETA) as catalytic complex allowed the formation of A3B mikto‐arm copolymers with different compositions and molecular weights. Selective deprotection of sugar protecting groups finally generated amphiphilic mikto‐arm copolymers. The molecular characterization of those copolymers was performed by 1H NMR spectroscopy and gel permeation chromatography (GPC) analysis. The self‐assembly of the copolymers into micellar aggregates and the related critical micellization concentration (CMC) in aqueous media were determined by dynamic light scattering (DLS) and UV‐visible spectroscopy, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3271–3280, 2010
Novel long chain unsaturated diisocyanate from fatty acid: Synthesis, characterization, and application in bio‐based polyurethane
Authors: Hojabri Leila , Kong Xiaohua , Narine Suresh S. 
Published: July 2010

AbstractA novel long chain linear unsaturated terminal diisocyanate, 1,16‐diisocyanatohexadec‐8‐ene (HDEDI) was synthesized from oleic acid via Curtius rearrangement. Its chemical structure was identified by FTIR, 1H NMR, 13C NMR, and HRMS. This diisocyanate was used as a starting material for the preparation of entirely bio‐based polyurethanes (PUs) by reacting it with canola diol and canola polyol, respectively. The physical properties and crystalline structure of the PUs prepared from this diisocyanate were compared to their counterparts prepared from similar fatty acid‐derived diisocyanate, 1,7‐heptamethylene diisocyanate (HPMDI). The HDEDI based PUs demonstrated various different properties compared to those of HPMDI based PUs. For example, HDEDI based PUs exhibited a triclinic crystal form; whereas HPMDI based PUs exhibited a hexagonal crystal lattice. In addition, canola polyol‐HDEDI PU demonstrated a higher tensile strength at break than that of canola polyol‐HPMDI, attributed to the higher degree of hydrogen bonding associated with the former sample. Nevertheless, lower Young's modulus and higher elongation in canola polyol‐HDEDI PU were obtained because of the flexibility of the long chain introduced by the HDEDI diisocyanate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3302–3310, 2010
Synthesis and characterization of donor–acceptor poly(3‐hexylthiophene) copolymers presenting 1,3,4‐oxadiazole units and their application to photovoltaic cells
Authors: Wang Hsu‐Shen , Su Ming‐Shin , Wei Kung‐Hwa 
Published: July 2010

AbstractWe have used Grignard metathesis polymerization to prepare poly(3‐hexylthiophene)‐based copolymers containing electron‐withdrawing 4‐tert‐butylphenyl‐1,3,4‐oxadiazole‐phenyl moieties as side chains. We characterized these copolymers using 1H and 13C nuclear magnetic resonance spectroscopy, thermogravimetric analysis, and gel permeation chromatography. The band gap energy of copolymer was determined from the onset of the optical absorption. The quenching effects were observed in the photoluminescence spectra of the copolymers incorporating pendant electron‐deficient 1,3,4‐oxadiazole moieties on the side chains. The photocurrents of devices were enhanced in the presence of an optimal amount of the 1,3,4‐oxadiazole moieties, thereby leading to improved power conversion efficiencies. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3331–3339, 2010
Synthesis and properties of new aromatic polyamides with redox‐active 2,4‐dimethoxytriphenylamine moieties
Authors: Hsiao Sheng‐Huei , Liou Guey‐Sheng , Kung Yi‐Chun , Hsiung Tzu‐Jung 
Published: July 2010

AbstractA new triphenylamine‐based diamine monomer, 4,4′‐diamino‐2″,4″‐dimethoxytriphenylamine (2), was synthesized from readily available reagents and was reacted with various aromatic dicarboxylic acids to produce a series of aromatic polyamides (4a–h) containing the redox‐active 2,4‐dimethoxy‐substituted triphenylamine (dimethoxyTPA) unit. All the resulting polyamides were readily soluble in polar organic solvents and could be solution cast into tough and flexible films. These polymers exhibited good thermal stability with glass transition temperatures of 243–289 °C and softening temperatures of 238–280 °C, 10% weight loss temperatures in excess of 470 °C in nitrogen, and char yields higher than 60% at 800 °C in nitrogen. The redox behaviors of the polymers were examined using cyclic voltammetry (CV). All these polyamides showed two reversible oxidation processes in the first CV scan. The polymers also displayed low ionization potentials as a result of their dimethoxyTPA moieties. In addition, the polymers displayed excellent stability of electrochromic characteristics with coloration change from a colorless neutral state to green and blue‐purple oxidized states. These anodically coloring polyamides showed high green coloration efficiency (CE = 329 cm2/C), high contrast of optical transmittance change (ΔT% = 84% at 829 nm), and long‐term redox reversibility. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3392–3401, 2010
Cyclic alkoxyamine‐initiator tethered by azide/alkyne‐“click”‐chemistry enabling ring‐expansion vinyl polymerization providing macrocyclic polymers
Authors: Narumi Atsushi , Zeidler Sylvia , Barqawi Haitham , Enders Claudia , Binder Wolfgang H. 
Published: July 2010

AbstractA cyclic initiator for the nitroxide‐mediated controlled radical polymerization (NMP) is a powerful tool for the preparation of macrocyclic polymers via a ring‐expansion vinyl polymerization mechanism. For this purpose, we prepared a Hawker‐type NMP‐initiator that includes an azide and a terminal alkyne as an acyclic precursor, which is subsequently tethered via an intramolecular azide/alkyne‐“click”‐reaction, producing the final cyclic NMP‐initiator. The polymerization reactions of styrene with cyclic initiator were demonstrated and the resultant polymers were characterized by the gel permeation chromatography (GPC) and the matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). These results prove that the ring‐expansion polymerization of styrene occurred together with the radical ring‐crossover reactions originating from the exchange of the inherent nitroxides generating macrocyclic polystyrenes with higher expanded rings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3402–3416, 2010
Hole‐transporting host‐polymer series consisting of triphenylamine basic structures for phosphorescent polymer light‐emitting diodes
Authors: Thesen Manuel W. , Höfer Bianca , Debeaux Marc , Janietz Silvia , Wedel Armin , Köhler Anna , Johannes Hans‐Hermann , Krueger Hartmut 
Published: July 2010

AbstractA series of novel styrene derived monomers with triphenylamine‐based units, and their polymers have been synthesized and compared with the well‐known structure of polymer ofN,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine with respect to their hole‐transporting behavior in phosphorescent polymer light‐emitting diodes (PLEDs). A vinyltriphenylamine structure was selected as a basic unit, functionalized at the para positions with the following side groups: diphenylamine, 3‐methylphenyl‐aniline, 1‐ and 2‐naphthylamine, carbazole, and phenothiazine. The polymers are used in PLEDs as host polymers for blend systems with the following device configuration: glass/indium–tin–oxide/PEDOT:PSS/polymer‐blend/CsF/Ca/Ag. In addition to the hole‐transporting host polymer, the polymer blend includes a phosphorescent dopant [Ir(Me‐ppy)3] and an electron‐transporting molecule (2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole). We demonstrate that two polymers are excellent hole‐transporting matrix materials for these blend systems because of their good overall electroluminescent performances and their comparatively high glass transition temperatures. For the carbazole‐substituted polymer (Tg= 246 °C), a luminous efficiency of 35 cd A−1and a brightness of 6700 cd m−2at 10 V is accessible. The phenothiazine‐functionalized polymer (Tg= 220 °C) shows nearly the same outstanding PLED behavior. Hence, both these polymers outperform the well‐known polymer ofN,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine, showing only a luminous efficiency of 7.9 cd A−1and a brightness of 2500 cd m−2(10 V). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3417–3430, 2010
Water‐soluble hyperbranched polyelectrolytes with high fluorescence quantum yield: Facile synthesis and selective chemosensor for Hg2+ and Cu2+ ions
Authors: Bao Biqing , Yuwen Lihui , Zhan Xiaowei , Wang Lianhui 
Published: July 2010

AbstractNew water‐soluble hyperbranched polyfluorenes bearing carboxylate side chains have been synthesized by the simple “A2 + B2 + C3” protocol based on Suzuki coupling polymerization. The linear polyfluorene analogue LPFA was also synthesized for comparative investigation. The optical properties of the neutral precursory polymers in CHCl3 and final carboxylic‐anionic conjugated polyelectrolytes in buffer solution were investigated. The obtained hyperbranched polyelectrolyte HPFA2 with lower content of branch unit (2%) showed excellent solubility and high fluorescence quantum yield (ϕF = 89%) in aqueous solution. Fluorescence quenching of HPFA2 by different metal ions was also investigated, the polyelectrolyte showed high selectivity for Hg2+ and Cu2+ ions relative to other various metal ions in buffer solution. The Stern‐Volmer constant Ksv was determined to be 0.80 × 106 M−1 for Hg2+ and 3.11 × 106 M−1 for Cu2+, respectively, indicating the potential application of HPFA2 as a highly selective and sensitive chemosensor for Hg2+ and Cu2+ ions in aqueous solution. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3431–3439, 2010
Thermo‐responsive glycopolymer chains grafted onto honeycomb structured porous films via RAFT polymerization as a thermo‐dependent switcher for lectin Concanavalin a conjugation
Authors: Min Eun Hee , Ting S. R. Simon , Billon Laurent , Stenzel Martina H. 
Published: July 2010

AbstractStable and surface‐modified films with regular porous arrays were created by crosslinking honeycomb structured porous films prepared via breath figures from poly(styrene‐co‐maleic anhydride). The formation of open or closed pores of the films was controlled by the addition of a polyion complex. Subsequent crosslinking of the films with 1,8‐diaminooctane led to films, which maintain their structure in solvents. In addition, excess amino functionality after crosslinking allowed the attachment of RAFT agent, 3‐benzylsulfanyl thiocarbonyl sulfanylpropionic acid, for the controlled surface polymerization of N‐isopropyl acrylamide (NIPAAm) and N‐acryloyl glucosamine (AGA). The attachment of thermo‐responsive glycopolymers onto the honeycomb structured porous films was confirmed using contact angle measurements and confocal fluorescence microscopy. Cleavage of surface anchored polymers via aminolysis revealed that the molecular weights of the surface grafted chains are significantly larger than the molecular weight of the chains generated in solution. The honeycomb structured porous films with their grafted PNIPAAm‐ran‐PAGA polymer chains showed selective recognition of Concanavalin A (ConA). Below the lower critical solution temperature (LCST) of the surface, the conjugation is switched off, while above the LCST the surface grafted glucose moieties bind strongly to ConA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3440–3455, 2010
Intrinsic viscosity of polyacrolein
Authors: Seibert E. E. 
Published: July 2010

AbstractWhen acrolein is polymerized to polyacrolein, a rapid control procedure is required in order to follow the degree of polymerization. Polyacrolein is insoluble in most organic liquids and in water but dissolves in sulfurous acid with the formation of a polyelectrolyte. Ionization of the polymer is suppressed by adding sodium sulfate, and consequently the viscosity of solutions with respect to concentration may be obtained. The intrinsic viscosity may be obtained from the viscosity of a single concentration by use of a correlation between specific viscosity and the product of intrinsic viscosity and concentration obtained from data on many four point determinations. The effects of various concentrations of suppression ions, the level of pH, aging of solutions, and some organic solvents are discussed. The variables which affect the intrinsic viscosity arts empirically established for the greatest degree of repeatability.
The crystallization of branched polymers. II. Substitutional solution of side chains
Authors: Vonk C. G. 
Published: July 2010

AbstractThe crystalline structure of bulk polyethylene containing short chain branches was investigated with the aid of small‐angle and wide‐angle x‐ray scattering. The crystalline density obtained from measurements of the invariant, the crystallinity, and the overall density were compared with the crystalline density following from the lattice constants. Good agreement was found for linear and alkyl branched samples; however systematic differences were observed for copolymers containing ester and carboxylic acid side groups. These results are explained by assuming the side groups to enter into the crystalline lattice by substitutional solution rather than at interstitial positions. The chains around the side groups would have to show a kinked structure. This type of crystallization is in agreement with the principle of optimal space filling laid down by Kitaigorodskii [5].
The Use of Rectus Sheath Catheters as an Analgesic Technique for Patients Undergoing Radical Cystectomy
Authors: Parsons B.A. , Aning J. , Daugherty M.O. , McGrath J.S. 
Published: July 2010

Introduction: Despite improvements in peri-operative care and the recent introduction of enhanced recovery protocols, radical cystectomy continues to be associated with a greater morbidity and a more prolonged in-patient stay than other urological procedures. There is significant scope for improvement and it is now well recognised that the analgesic technique used can impact on post-operative recovery. In this paper, we report on our early experience of using bilateral rectus sheath catheters (RSC) and highlight potential benefits of the technique. Methods: Over a 12-month period between November 2007 and November 2008, 20 patients underwent a radical cystectomy performed by a single surgeon and anaesthetist. Ten patients had bilateral rectus sheath catheters sited under ultrasound-guidance and they were compared to a preceding group of 10 patients who had epidural catheters inserted. Data were analysed retrospectively and primary outcome measures included pain scores, ileus rates, time to bowel opening and length of stay. Results: The demographics of the two groups showed no significant differences. Analgesic effect was equivalent between the groups. The time to passage of flatus and bowel opening was similar between the 2 groups. There was a slightly lower ileus rate and a shorter median length of stay in the RSC group (13 vs. 15 days) though the data are non-randomised and case numbers were small. Practical benefits in the placement and post-operative care of the RSCs were also observed. Conclusion: The rectus sheath block is a novel analgesic technique that appears to have an equivalent analgesic effect to epidurals in this early observational case series. RSCs have other potential advantages including earlier mobilisation and reduced burden on nursing and medical staff, thus making it ideally suited to an enhanced recovery protocol. Larger studies are needed to confirm the findings of the current case series.
Role of vasodilator stimulated phosphoprotein in VEGF induced blood–brain barrier permeability in endothelial cell monolayers
Authors: Davis Brandon , Tang Jun , Zhang Li , Mu Dezhi , Jiang Xiangning , Biran Valerie , Vexler Zinaida , Ferriero Donna M. 
Published: July 2010

AbstractThe blood–brain barrier (BBB) plays an important role in the pathophysiology of central nervous system (CNS) disorders such as stroke and hypoxic–ischemic brain injury. Vascular endothelial growth factor (VEGF) is involved in angiogenesis and vasogenic edema during stroke and hypoxia. However, the role of VEGF in BBB permeability after hypoxia has not been fully elucidated. We therefore investigated VEGF effects in an in vitro BBB model using rbcec4 endothelial cell line with the stimulation of VEGF or hypoxia. In this study, BBB permeability was studied using 14C‐sucrose detection. The expression of BBB tight junction protein ZO‐1, and the expression and phosphorylation of vasodilator stimulated phosphoprotein (VASP), VEGF and VEGF receptor 2 (VEGFR2) were determined using fluorescent immunocytochemistry and western blot analyses. We found that hypoxia upregulated VEGF expression, and VEGF increased BBB permeability. Hypoxia also increased VASP phosphorylation, which was mediated, in part, through VEGFR2. We also found that VASP at tight junctions was co‐localized with ZO‐1 in cell–cell contacts. Our findings show that VASP phosphorylation is affected by hypoxia and VEGFR2 inhibition suggesting a role for VASP in BBB permeability.
A double-blind, placebo-controlled, cross-over study to establish the bifidogenic effect of a very-long-chain inulin extracted from globe artichoke (Cynara scolymus) in healthy human subjects
Authors: Costabile Adele , Kolida Sofia , Klinder Annett , Gietl Eva , Bäuerlein Michael , Frohberg Claus , Landschütze Volker , Gibson Glenn R. 
Published: July 2010

There is growing interest in the use of inulins as substrates for the selective growth of beneficial gut bacteria such as bifidobacteria and lactobacilli because recent studies have established that their prebiotic effect is linked to several health benefits. In the present study, the impact of a very-long-chain inulin (VLCI), derived from globe artichoke (Cynara scolymus), on the human intestinal microbiota compared with maltodextrin was determined. A double-blind, cross-over study was carried out in thirty-two healthy adults who were randomised into two groups and consumed 10 g/d of either VLCI or maltodextrin, for two 3-week study periods, separated by a 3-week washout period. Numbers of faecal bifidobacteria and lactobacilli were significantly higher upon VLCI ingestion compared with the placebo. Additionally, levels ofAtopobiumgroup significantly increased, whileBacteroides–Prevotellanumbers were significantly reduced. No significant changes in faecal SCFA concentrations were observed. There were no adverse gastrointestinal symptoms apart from a significant increase in mild and moderate bloating upon VLCI ingestion. These observations were also confirmed byin vitrogas production measurements. In conclusion, daily consumption of VLCI extracted from globe artichoke exerted a pronounced prebiotic effect on the human faecal microbiota composition and was well tolerated by all volunteers.