bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amphiphilic diblock copolymers poly(2‐hydroxyethylmethacrylate)‐b‐(N‐phenylmaleimide) and poly(2‐hydroxyethylmethacrylate)‐b‐(styrene) using the macroinitiator poly(HEMA)‐Cl by ATRP: Preparation, characterization, and thermal properties
Authors: Pizarro Guadalupe del C. , Marambio Oscar G. , Jeria‐Orell Manuel , Flores Mario E. , Rivas Bernabé L. 
Published: July 2010

AbstractIn recent years, much attention has been given to the development of specialty polymers from useful materials. In this context, amphiphilic block copolymers were prepared by atom transfer radical polymerization (ATRP) of N‐phenylmaleimide (N‐PhMI) or styrene using a poly(2‐hydroxyethylmethacrylate)‐Cl macroinitiator/CuBr/bipyridine initiating system. The macroinitiator P(HEMA)‐Cl was directly prepared in toluene by reverse ATRP using BPO/FeCl3 6 H2O/PPh3 as initiating system. The microstructure of the block copolymers were characterized using FTIR, 1H‐NMR, 13C‐NMR spectroscopic techniques and scanning electron microscopy (SEM). The thermal behavior was studied by differential scanning calorimetry (DSC), and thermogravimetry (TG). The theoretical number average molecular weight (Mn,th) was calculated from the feed capacity. The microphotographs of the film's surfaces show that the film's top surfaces were generally smooth. The TDT of the block copolymer P(HEMA)80‐b‐P(N‐PhMI)20 and P(HEMA)90‐b‐P(St)10 of about 290°C was also lower than that found for the macroi′nitiator poly(HEMA)‐Cl. The block copolymers exhibited only one Tg before thermal decomposition, which could be attributed to the low molar content of the N‐PhMI or St blocks respectively. This result also indicates that the phase behavior of the copolymers is predominately determined by the HEMA block. The curves reveal that the polymers show phase transition behavior of amorphous polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Analysis of the structure and mass transport properties of clay nanocomposites based on amorphous PET
Authors: Greco A. , Corcione C. Esposito , Strafella A. , Maffezzoli A. 
Published: July 2010

AbstractThe aim of this work is to characterize the rheological and permeability behavior of nanocomposites based on amorphous poly(ethylene terephthalate) (PETg) and organically modified montmorillonites (omMMT), obtained by melt intercalation. The use of PETg instead of semicrystalline PET is believed to reduce the risks associated to organic modifier degradation during processing at high temperatures. X‐ray and transmission electron microscopy analysis performed on the PETg nanocomposites showed that processing for long time at temperatures lower than melting of semicrystalline PET allowed to obtain a partially intercalated structure with some degree of exfoliation. The rheological behavior of PETg nanocomposites was studied as a function of shear rate in a cone–plate rheometer in order to correlate the viscosity with the aggregation state of omMMT. A simple model accounting for an apparent increase of rheological units size, associated with the intercalation of PETg macromolecules into omMMT galleries, is proposed. The glass transition temperature, Tg, as a function of the volume fraction of omMMT content of the nanocomposite, was measured using differential scanning calorimetry. Finally, the water vapour permeability of PETg nanocomposites was correlated to the volume fraction of the impermeable inorganic part of the omMMT. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Studies on the thermal stability and degradation kinetics of Pd/PC nanocomposites
Authors: Onbattuvelli Valmikanathan P. , Rochefort Willie E. , Simonsen John , Park Seong‐Jin , German Randall M. , Atre Sundar V. 
Published: July 2010

AbstractEffect of heating rate, Pd content, and synthesis method on the thermal stability of the ex situ and in situ Palladium/polycarbonate (Pd/PC) nanocomposites was investigated. TEM images revealed discrete Pd nanoclusters of about 5 and 15 nm sizes for 1 and 2 vol % ex situ nanocomposites, respectively. However, agglomerated Pd nanoclusters were noticed in the in situ samples, irrespective of the Pd content. The ex situ Pd/PC nanocomposites showed high onset temperature (Ti) for thermal degradation of PC than the in situ and pure PC samples. Pd content and heating rates were found to have a positive influence on the Ti and Tm (temperature at the maximum degradation rate occurs) of the Pd/PC nanocomposites. Thermal degradation of the PC was found to follow the first‐order kinetics in the Pd/PC nanocomposites. The activation energies associated with the degradation were determined by using the Kissinger method. These activation energies are used to construct the Master decomposition curve (MDC) and weight–time–temperature (α–t–T) plots that describe the time‐temperature dependence of the PC pyrolysis in the Pd/PC nanocomposites. These constructed α–t–T plots were validated with the data from isothermal measurements. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of epoxy resin contents on the rheological properties of epoxy‐asphalt blends
Authors: Peiliang Cong , Jianying Yu , Shuanfa Chen 
Published: July 2010

AbstractEpoxy‐asphalt and its mixture have been proposed for the long span orthotropic steel deck bridges because it shows excellent heat resistance, free from bleeding, low temperature cracking resistance, and aggregate scattering resistance. In this study, the effects of epoxy resin contents on rheological properties of epoxy‐asphalt binders were studied using dynamic shear rheometer. Experimental results indicated that the improvement of the viscoelastic performance of asphalt binder is noticeable at high temperatures, at which the elasticity is increased (higher G* and lower δ) for epoxy‐asphalt with increase in epoxy resin contents. The viscous behavior of the asphalt also increased when epoxy resin is added. Creep test results indicated that epoxy‐asphalt binder can not only resist deformation at elevated temperatures but recover satisfactorily from strain. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of alginate‐g‐vinyl sulfonic acid with a potassium peroxydiphosphate/thiourea system
Authors: Sand Arpit , Yadav Mithilesh , Behari Kunj 
Published: July 2010

AbstractAlginate‐g‐vinyl sulfonic acid graft copolymer was synthesized through the graft copolymerization of vinyl sulfonic acid (VSA) onto alginate with an efficient system, i.e., potassium peroxydiphosphate (PDP)/thiourea in an aqueous medium. The effects of the concentration of thiourea, PDP, hydrogen ion, alginate, and VSA along with the time and temperature on the graft copolymerization were studied by the determination of the grafting parameters (grafting ratio, add‐on, conversion, grafting efficiency, and homopolymer). The synthesized graft copolymer was characterized by FTIR analysis. Thermogravimetric analysis showed that the alginate‐g‐vinyl sulfonic acid is thermally more stable than alginate. Water swelling capacity, metal ion sorption, flocculation, and resistance to biodegradability studies of synthesized graft copolymer have been performed with respect to the parent polymer. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Macroporous crosslinked hydrophobic/hydrophilic polystyrene/polyamide interpenetrating polymer network: Synthesis, characterization, and adsorption behaviors for quercetin from aqueous solution
Authors: Liao Wenwen , Gao Shuqin , Xie Xianglin , Xu Mancai 
Published: July 2010

AbstractIn the present study, a novel hydrophobic/hydrophilic polystyrene/polyamide interpenetrating polymer network (PS/PAM IPN) was synthesized and its molecular structure was characterized by Fourier transform infrared ray (FT‐IR) spectrum, chemical analysis, swelling test, and N2 adsorption‐desorption experiment. The obtained PS/PAM IPN was employed as a polymeric adsorbent to adsorb quercetin from aqueous solution, and the adsorption thermodynamics were calculated according to thermodynamic equations. It was found that no chemical bond was formed between PS and PAM and PS/PAM IPN held characters of amphiphilic polymer network (APN). The adsorption isotherms could be well fitted by Freundlich isotherm, and the adsorption was shown to be an exothermic, spontaneous, and more ordered process. The total adsorption capacity from the column adsorption experiment was measured to be 8.6 mg/mL wet resin, and the adsorbed quercetin on PS/PAM IPN could be easily desorbed by 10% of hydrochloric acid‐ethanol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Improvement of mechanical performance of epoxy resins filled with cobalt and chromium powders
Authors: El Homrany M. , Maaroufi A. , Benavente R. , Pereña J. M. , Pinto G. , Halim M. 
Published: July 2010

AbstractEpoxy/ powder metal composites have interesting electrical properties, becoming conductors above the percolation threshold. To complete this study, mechanical investigations have been carried out to show the influence of the fillers on the mechanical performance of these composites. In this framework, different epoxy/metallic powders (Cobalt, Chromium) composites were prepared. Scanning Electron Microscopy showed that the dispersion of the metallic fillers in the matrix is almost homogeneous. The dynamic mechanical thermal analysis (DMTA) measurements showed the dependence of the viscoelastic parameters with the frequency, temperature, nature, and content of fillers. The main relaxations observed are the primary α relaxation (associated to the glass transition, Tg) and a secondary β relaxation. A second DMTA run on the same samples showed a slight increase of the Tg. It clearly showed that the used metallic fillers improve the mechanical properties of the obtained composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Organic‐soluble chitosan/polyhydroxybutyrate ultrafine fibers as skin regeneration prepared by electrospinning
Authors: Ma Guiping , Yang Dongzhi , Wang Kemin , Han Jing , Ding Shumin , Song Guoqiang , Nie Jun 
Published: July 2010

AbstractIn the present contribution, the ultrafine fiber membranes of polyhydroxybutyrate (PHB) and organic‐soluble chitosan(O‐CS) was prepared by electrospinning. The structure and thermal stability were studied by infrared (FTIR) and thermogravimetric analysis (TG). The surface properties of ultrafine fibers were estimated by contact angle measurements using water. The morphology was observed by scanning electron microscopy (SEM). The cytotoxicity assessment with mouse fibroblast cells (L929) was also investigated. Cell culture results showed that it benefits promoting the cell attachment and proliferation. The results showed it could be as tissue engineering for skin regeneration. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The N‐Arylamino Conjugation Effect in the Photochemistry of Fluorescent Protein Chromophores and Aminostilbenes
Authors: Huang Guan‐Jhih , Yang Jye‐Shane 
Published: July 2010

AbstractTo understand the nonradiative decay mechanism of fluorescent protein chromophores in solutions, a systematic comparison of a series of (Z)‐4‐(N‐arylamino)benzylidene‐2,3‐imidazolinones (ABDIs: 2P, 2PP, 2OM, and 2OMB) and the corresponding trans‐4‐(N‐arylamino)‐4′‐cyanostilbenes (ACSs: 1P, 1PP, 1OM, and 1OMB) was performed. We have previously shown that the parameter Φf+2 Φtc, in which Φf and Φtc are the quantum yields of fluorescence and trans→cis photoisomerization, respectively, is an effective probe for evaluating the contribution of twisted intramolecular charge transfer (TICT) states in the excited decays of trans‐aminostilbenes, including the push–pull ACSs. One of the criteria for postulating the presence of a TICT state is Φf+2 Φtc≪1.0, because its formation is decoupled with the CC bond (τ) torsion pathway and its decay is generally nonradiative. Our results show that the same concept also applies to ABDIs 2 with the parameter Φf+2 ΦZE in which ΦZE is the quantum yield of Z→E photoisomerization. We conclude that the τ torsion rather than the CC bond (φ) torsion is responsible for the nonradiative decays of ABDIs 2 in aprotic solvents (hexane, THF, acetonitrile). The phenyl‐arylamino CN bond (ω) torsion that leads to a nonradiative TICT state is important only for 2OM in THF and acetonitrile. If the solvent is protic (methanol and 10–20 % H2O in THF), a new nonradiative decay channel is present for ABDIs 2, but not for ACSs 1. It is attributed to internal conversion (IC) induced by solvent (donor)–solute (acceptor) hydrogen‐bonding (HB) interactions. The possible HB modes and the concept of τ torsion‐coupled proton transfer are also discussed.
Facile and Efficient Reduction of Ketones in the Presence of Zinc Catalysts Modified by Phenol Ligands
Authors: Enthaler Stephan , Eckhardt Björn , Inoue Shigeyoshi , Irran Elisabeth , Driess Matthias 
Published: July 2010

AbstractIn the present study, the zinc‐catalyzed hydrosilylation of various ketones to give their corresponding alcohols has been examined in detail. Diethyl zinc that can be modified by easily accessible phenol ligands allows the efficient reduction of various aryl and alkyl ketones. By using a practical in situ catalyst, excellent turnover frequencies up to 1000 h−1 and a broad functional group tolerance were achieved.
Consumer eco‐innovation adoption: assessing attitudinal factors and perceived product characteristics
Authors: Jansson Johan 
Published: July 2010

AbstractFor business and environmental reasons, increased understanding of green consumer behavior is essential. This paper addresses consumer adoption and non‐adoption of a high involvement eco‐innovation (the alternative fuel vehicle, AFV). The purpose is to integrate two research streams to explore factors driving and hindering adoption. The factors are rooted in environmental psychology research and the diffusion of innovation literature. Survey results on Swedish car owners are reported. The results indicate that adopters and non‐adopters differ on norms, attitudes, novelty seeking and on how innovation attributes are perceived. Furthermore, the results show that the groups rank car attributes such as fuel consumption and carbon dioxide emissions differently. The main contribution of the paper is the integration of norms and attitudes together with consumer adoption factors in analyzing green consumer behavior in relation to a high involvement product. The implications for business and marketing strategy and for environmental policy are discussed. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
A Novel Sulfated Holostane Glycoside from Sea Cucumber Holothuria leucospilota
Authors: Han Hua , Zhang Wen , Yi Yang‐Hua , Liu Bao‐Shu , Pan Min‐Xiang , Wang Xiao‐Hua 
Published: July 2010

AbstractA new sulfated holostane glycoside, leucospilotaside B (1), together with the two related structurally known compounds holothurin B2 (2) and holothurin B (3), was isolated from sea cucumber Holothuria leucospilota collected from the South China Sea. The structure of 1 was elucidated by spectral analysis (1H‐, 13C‐, and 2D‐NMR, ESI‐MS, and HR‐ESI‐MS) and chemical methods. The compounds 1–3 possess the same disaccharide moiety, but were different in the side chains of the triterpene aglycone. Compound 1 showed significant cytotoxicities against four human tumor cell lines, HL‐60, MOLT‐4, A‐549, and BEL‐7402.
The Chemical Constituents of Endophytic Fungus Trichoderma sp. MFF‐1
Authors: Li Guo‐Hong , Wang Xing‐Biao , Liu Fang‐Fang , Dang Li‐Zhi , Li Lei , Yang Zhong‐Shan , Xin Xiong , Zhang Ke‐Qin 
Published: July 2010

AbstractA fungal strain named MFF‐1 was isolated from the flower of Pyrethrum cinerariifolium. Based on the sequence at the internal transcribed spacer (ITS) region, this strain was identified as a Trichoderma sp. Two new compounds, including a mitorubrin derivative and its potential biogenetic precursor, together with a known compound, were isolated from the cultures of the endophytic fungus. Their structures were established by spectroscopic methods and determined to be (3S*,6R*,7R*)‐3,4,5,6,7,8‐hexahydro‐7‐hydroxy‐7‐methyl‐8‐oxo‐3‐[(E)‐prop‐1‐enyl]‐1H‐isochromen‐6‐yl 2,4‐dihydroxy‐6‐methylbenzoate (1), named deacetylisowortmin, (E)‐2‐(hydroxymethyl)‐3‐(2‐hydroxypent‐3‐enyl)phenol (2), and wortmannin (3). All compounds were assayed for antimicrobial activity. Compound 3 showed activity against Candida albicans and Bacillus cereus.
1,2,3‐Thiadiazole Thioacetanilides. Part 2
Authors: Zhan Peng , Liu Xin‐Yong , Li Zhen‐Yu , Fang Zeng‐Jun , Pannecouque Christophe , De Clercq Erik 
Published: July 2010

AbstractAs part of our studies to discover new HIV‐1 reverse transcriptase inhibitors, a series of 3,4‐dichlorophenyl substituted 1,2,3‐thiadiazole thioacetanilide (TTA=[(1,2,3‐thiadiazole‐5‐yl)sulfanyl]acetanilide) derivatives were synthesized, and in vitro anti‐HIV activity was evaluated. The results revealed that nearly half of the compounds show moderate‐to‐good inhibitory potency against HIV‐1. In particular, compound 7f is highly potent, with an EC50 value of 0.95±0.33 μM. The preliminary structure–activity relationship among the newly synthesized congeners is discussed.
Antimutagenic and Antioxidant Potentials of Teucrium ramosissimum Essential Oil
Authors: Sghaier Mohamed Ben , Boubaker Jihed , Neffati Aicha , Limem Ilef , Skandrani Ines , Bhouri Wissem , Bouhlel Ines , Kilani Soumaya , Chekir‐Ghedira Leila , Ghedira Kamel 
Published: July 2010

AbstractThe mutagenic and antimutagenic effects of the essential oil extracted from the aerial parts of Teucrium ramosissimum were evaluated by the bacterial reverse mutation assay in Salmonella typhimurium TA98, TA100, and TA1535, with and without exogenous metabolic activation (S9 fraction). The T. ramosissimum essential oil showed no mutagenic effect. In contrast, our results established that it possessed antimutagenic effects against sodium azide (SA), aflatoxin B1 (AFB1), benzo[a]pyrene (B[a]P), and 4‐nitro‐o‐phenylenediamine (NOPD). The antioxidant capacity of the tested essential oil was evaluated using enzymatic, i.e., the xanthine/xanthine oxidase (X/XOD) assay, and nonenzymatic systems, i.e., the nitro‐blue tetrazolium (NBT)/riboflavin and the DPPH assays. A moderate free radical‐scavenging activity was observed towards DPPH. and O$\rm{{_{2}^{{^\cdot} -}}}$. In contrast, T. ramosissimum essential oil showed no effect for all the tested concentrations in the X/XOD assay.
Triterpenoid Alkaloids from Buxus microphylla
Authors: Yan Yu‐Xin , Chen Jian‐Chao , Sun Yun , Wang Yuan‐Yuan , Su Jia , Li Yan , Qiu Ming‐Hua 
Published: July 2010

AbstractTwo new triterpenoid alkaloids, buxmicrophyllines J and K (1 and 2, resp.), together with four analogues, 3–6, were isolated from the leaves and stems of Buxus microphylla. The structures of the new compounds were elucidated by NMR and MS spectroscopic analyses. The partial assignments of the NMR spectra of 3 were also revised. Compounds 1 and 3–6 were evaluated for their growth inhibitory activity against human cell lines HL‐60, SMMC‐7721, A‐549, SK‐BR‐3, and PANC‐1. Compound 6 showed significant cytotoxicity against HL‐60, SK‐BR‐3, and PANC‐1 cell lines, with IC50 values of 6.46, 19.61, and 28.57 μM, respectively.
A New Quinolone and Other Constituents from the Fruits of Tetradium ruticarpum: Effects on Neutrophil Pro‐Inflammatory Responses
Authors: Wang Tzu‐Ying , Wu Jin‐Bin , Hwang Tsong‐Long , Kuo Yueh‐Hsiung , Chen Jih‐Jung 
Published: July 2010

AbstractThe fruit of Tetradium ruticarpum is widely used in healthcare products for the improvement of blood circulation, headache, abdominal pain, amenorrhea, chill limbs, migraine, and nausea. A new quinolone, 2‐[(6Z,9Z)‐pentadeca‐6,9‐dienyl]quinolin‐4(1H)‐one (1), has been isolated from the fruits of T. ruticarpum, together with eleven known compounds. The structure of the new compound was determined by NMR and MS analyses. Rutaecarpine (4), evodiamine (5), and skimmianine (7) exhibited inhibition (IC50≤20.9 μM) of O$\rm{{_{2}^{{^\cdot} -}}}$ generation by human neutrophils in response to N‐formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine/cytochalasin B (fMLP/CB). In addition, 1, evocarpine (2), 4, 7, and evodol (8) inhibited fMLP/CB‐induced elastase release with IC50 values ≤14.4 μM.
Structure–Activity Relationship Studies on Derivatives of Eudesmanolides from Inula helenium as Toxicants against Aedes aegypti Larvae and Adults
Authors: Cantrell Charles L. , Pridgeon Julia W. , Fronczek Frank R. , Becnel James J. 
Published: July 2010

AbstractAn Aedes aegypti larval toxicity bioassay was performed on compounds representing many classes of natural compounds including polyacetylenes, phytosterols, flavonoids, sesquiterpenoids, and triterpenoids. Among these compounds, two eudesmanolides, alantolactone, and isoalantolactone showed larvicidal activities against Ae. aegypti and, therefore, were chosen for further structure–activity relationship study. In this study, structural modifications were performed on both alantolactone and isoalantolactone in an effort to understand the functional groups necessary for maintaining and/or increasing its activity, and to possibly lead to more effective insect‐control agents. All parent compounds and synthetic modification reaction products were evaluated for their toxic activities against Ae. aegypti larvae and adults. Structure modifications included epoxidations, reductions, catalytic hydrogenations, and Michael additions to the α,β‐unsaturated lactones. None of the synthetic isomers synthesized and screened against Ae. aegypti larvae were more active than isoalantolactone itself which had an LC50 value of 10.0 μg/ml. This was not the case for analogs of alantolactone for which many of the analogs had larvicidal activities ranging from 12.4 to 69.9 μg/ml. In general, activity trends observed from Ae. aegypti larval screening were not consistent with observations from adulticidal screening. The propylamine Michael addition analog of alantolactone was the most active adulticide synthesized with an LC50 value of 1.07 μg/mosquito. In addition, the crystal structures of both alantolactone and isoalantolactone were determined using CuKα radiation, which allowed their absolute configurations to be determined based on resonant scattering of the light atoms.
A Genetic Circuit System Based on Quorum Sensing Signaling for Directed Evolution of Quorum‐Quenching Enzymes
Authors: Kim Jin‐Hyun , Lee Sang‐Chul , Kyeong Hyun‐Ho , Kim Hak‐Sung 
Published: July 2010

AbstractQuorum sensing is a cell–cell communication mechanism that is involved in the regulation of biological functions such as luminescence, virulence, and biofilm formation. Quorum‐quenching enzymes, which interrupt quorum‐sensing signaling through degradation of quorum‐sensing molecules, have emerged as a new approach to controlling and preventing bacterial virulence and pathogenesis. In an effort to develop quorum‐quenching enzymes with improved catalytic activities, a genetic circuit system based on acylhomoserine‐lactone (AHL)‐mediated quorum‐sensing signaling was constructed. The genetic circuit system was composed of lux‐R, lux‐I promoter, β‐lactamase, and β‐lactamase inhibitor, and designed to confer antibiotic resistance on host cells expressing an AHL‐degrading enzyme, thereby enabling rapid screening of quorum‐quenching enzymes. To demonstrate the utility of the genetic circuit system, we attempted the directed evolution of the AHL hydrolase from Bacillus sp. The genetic circuit system was shown to be effective in screening of quorum‐quenching enzymes with high catalytic efficiency. From these results it is expected that the genetic circuit system can be widely used for the isolation and directed evolution of quorum‐quenching enzymes with greater potential.