bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrimination of three medicinal materials from the Citrus genus by HPLC fingerprint coupled with two complementary software
Authors: Qin Xue‐Mei , Dai Yun‐Tao , Zhang Li‐Zeng , Guo Xiao‐Qing , Shao Hong‐Xia 
Published: June 2009

AbstractIntroductionPericarpium Citri Reticulatae, Pericarpium Citri Reticulatae Viride and Fructus Aurantii come from the fruit of Citrus genus and possess analogous pharmacological activities. Either two or three of them are often present in one preparation. However, there is no standard method to differentiate the three herbal medicines for quality control.ObjectiveTo develop a fingerprint method for authentication of these three herbal medicines by HPLC.MethodologyMethanol extracts were analysed by HPLC, with a mobile phase of 0.1% phosphoric acid in water (A) and acetonitrile (B) in a gradient programme. The flow rate was set at 0.8 mL/min and UV detection at 320 nm. Principal component analysis and similarity evaluation were employed to analyse the chromatographic dataset.ResultsThe chromatograms of 20 Pericarpium Citri Reticulatae, 13 Pericarpium Citri Reticulatae Viride and 15 Fructus Aurantii samples from diverse habitats had 13 peaks in common, and showed one peak characteristic for Pericarpium Citri Reticulatae Viride and two peaks characteristic for Fructus Aurantii. Furthermore, it was possible to differentiate the three medicines by a ‘fingerprint region’. The difference between Pericarpium Citri Reticulatae and Fructus Aurantii was much bigger than that between Pericarpium Citri Reticulatae and Pericarpium Citri Reticulatae Viride, as could be shown by calculation of common peak ratio and variation peak ratio.ConclusionA reliable HPLC fingerprint method coupled with principal component analysis and similarity evaluation was developed and showed substantial differentiation power for the three medicines. Copyright © 2009 John Wiley & Sons, Ltd.
Curing of diglycidyl ether of bisphenol‐A epoxy resin using a poly(aryl ether ketone) bearing pendant carboxyl groups as macromolecular curing agent
Authors: Liu Fuhua , Wang Zhonggang , Liu Dan , Li Jianfeng 
Published: June 2009

AbstractBACKGROUND: Reactive thermoplastics have received increasing attention in the field of epoxy resin toughening. This paper presents the first report of using a novel polyaryletherketone bearing one pendant carboxyl group per repeat unit to cure the diglycidyl ether of bisphenol‐A epoxy resin (DGEBA). The curing reactions of DGEBA/PEK‐L mixtures of various molar ratios and with different catalysts were investigated by means of dynamic differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy methods.RESULTS: FTIR results for the DGEBA/PEK‐L system before curing and after curing at 135 °C for different times demonstrated that the carboxyl groups of PEK‐L were indeed involved in the curing reaction to form a crosslinked network, as evidenced by the marked decreased peak intensities of the carboxyl group at 1705 cm−1 and the epoxy group at 915 cm−1 as well as the newly emerged strong absorptions of ester bonds at 1721 cm−1 and hydroxyl groups at 3447 cm−1. Curing kinetic analysis showed that the value of the activation energy (Ea) was the highest at the beginning of curing, followed by a decrease with increasing conversion (α), which was attributed to the autocatalytic effect of hydroxyls generated in the curing reaction.CONCLUSION: The pendant carboxyl groups in PEK‐L can react with epoxy groups of DGEBA during thermal curing, and covalently participate in the crosslinking network. PEK‐L is thus expected to significantly improve the fracture toughness of DGEBA epoxy resin. Copyright © 2009 Society of Chemical Industry
Toughening effects of poly(butylene terephthalate) with blocked isocyanate‐functionalized poly(ethylene octene)
Authors: Yin Ligang , Shi Dean , Liu Yanlong , Yin Jinghua 
Published: June 2009

AbstractBACKGROUND: Blocked isocyanate‐functionalized polyolefins have great potential for use in semicrystalline polymer blends to obtain toughened polymers. In this study, poly(butylene terephthalate) (PBT) was blended with allyl N‐[2‐methyl‐4‐(2‐oxohexahydroazepine‐1‐carboxamido)phenyl] carbamate‐functionalized poly(ethylene octene) (POE‐g‐AMPC).RESULTS: New peaks at 2272 and 1720 cm−1, corresponding to the stretching vibrations of NCO and the carbonyl of NHCON, respectively, in AMPC, appeared in the infrared spectrum of POE‐g‐AMPC. Both rheological and X‐ray photoelectron spectroscopy results indicated a new copolymer was formed in the reactive blends. Compared to uncompatibilized PBT/POE blends, smaller dispersed particle sizes with narrower distribution were found in the compatibilized PBT/POE‐g‐AMPC blends. There was a marked increase in impact strength by about 10‐fold over that of PBT/POE blends with the same rubber content and almost 30‐fold higher than that of pure PBT when the POE‐g‐AMPC content was 25 wt%.CONCLUSION: The blocked isocyanate‐functionalized POE is an effective toughener for semicrystalline polymers. Super‐toughened PBT blends can be obtained when the POE‐g‐AMPC content is equal to or more than 15 wt%. Copyright © 2009 Society of Chemical Industry
Influence of chain microstructure on the hydrolytic degradation of copolymers from 1,3‐trimethylene carbonate and L‐lactide
Authors: Hua Jiajie , Gebarowska Katarzyna , Dobrzynski Piotr , Kasperczyk Janusz , Wei Jia , Li Suming 
Published: June 2009

AbstractRing‐opening copolymerization of L‐lactide (LLA) and 1,3‐trimethylene carbonate (TMC) blends with LLA/TMC feed ratios from 90/10 to 50/50 was realized at 110 or at 180 °C for various time periods, using low toxic zirconium (IV) acetylacetonate (Zr(Acac)4) as initiator. The resulting copolymers exhibit different chain microstructures. Copolymers obtained at 110 °C exhibit a gradient chain structure with the presence of lactidyl sequences next to very short ones, and are semicrystalline. In contrast, copolymers obtained at 180 °C are amorphous because of a more random chain microstructure with the presence of larger amounts of medium sequences. Degradation of the copolymers was carried out in pH 7.4 phosphate buffer at 37 °C. Analytical techniques such as 1H NMR, DSC, GPC, and XRD were used to monitor the degradation. Initially amorphous copolymers can remain amorphous during degradation because of the highly random unit's distribution, and equivalent LLA and TMC contents. However, initially amorphous copolymers containing larger amounts of lactidyl units are able to crystallize during degradation because of the presence of relatively long LLA blocks. Insofar, as initially semicrystalline copolymers are concerned, degradation occurs preferentially in the amorphous zones. Therefore, various degradation behaviors and degradation rates can be obtained by varying the chemical composition, chain microstructure, and morphology of PLLA‐PTMC copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3869–3879, 2009
Effects of polydepsipeptide side‐chain groups on the temperature sensitivity of triblock copolymers composed of polydepsipeptides and poly(ethylene glycol)
Authors: Ohya Yuichi , Yamamoto Hidetoshi , Nagahama Koji , Ouchi Tatsuro 
Published: June 2009

AbstractTo develop new types of biodegradable polymers possessing predictable responses to changes in temperature, ABA‐type and BAB‐type triblock copolymers composed of various polydepsipeptides (PDP) and poly(ethylene glycol) (PEG) (PDP‐PEG‐PDP and PEG‐PDP‐PEG) were synthesized. The specific focus of this study was on the effect of the different side‐chain groups of various amino acids on the temperature‐responsive behavior of the triblock copolymers. An ABA‐type triblock copolymer containing the less hydrophobic glycine (PGG‐PEG‐PGG) did not exhibit any temperature‐responsive behavior; however, ABA‐type triblock copolymers containing the hydrophobic α‐amino acids, L‐leucine and L‐phenylalanine (PGL‐PEG‐PGL or PGF‐PEG‐PGF), did exhibit temperature‐responsive behavior. The cloud point of PGF‐PEG‐PGF was 10 °C lower than that of PGL‐PEG‐PGL. It can be possible to control temperature‐sensitivity by changing not only PDP segment length but also kind of α‐amino acid in PDP segment. Moreover, BAB‐type triblock copolymer containing L‐leucine (PEG‐PGL‐PEG) showed temperature‐responsive sol‐gel transition. Because polydepsipeptides are biodegradable polymers, the information obtained in this study is useful to design biodegradable injectable polymers having controllable temperature‐sensitivity for biomedical use.© 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3892–3903, 2009
Synthesis and properties of poly(sulfone‐arylate) copolymers
Authors: Stephen Ranimol , Gibon Cécile M. , Weber Martin , Gaymans Reinoud J. 
Published: June 2009

AbstractPoly(sulfone‐arylate) was synthesized in a reaction between dihydroxy polysulfone prepolymers and either diphenyl terephthalate or terephthaloyl chloride. The dihydroxy polysulfone prepolymers had molecular weights of 2000 and 4000 g/mol. The polymerization with diphenyl terephthalate was carried out at high temperature (280 °C) in the presence of a catalyst, whereas the polymerization with terephthalic chloride was conducted in solution at low temperature in the presence of an acid acceptor. High‐molecular weight copolymers (ηinh ∼ 0.60 dL/g) could be obtained through both methods. The copolymers were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, DMA, and differential scanning calorimetry measurements and were found to exhibit high Tg values. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3904–3913, 2009
Synthesis of dendritic macromolecules through divergent iterative thio‐bromo “Click” chemistry and SET‐LRP
Authors: Rosen Brad M. , Lligadas Gerard , Hahn Christian , Percec Virgil 
Published: June 2009

AbstractThe development of a novel nucleophilic thio‐bromo “Click” reaction, specifically base‐mediated thioetherification of thioglycerol with α‐bromoesters was reported in an earlier article. The combination of this thio‐bromo click reaction with subsequent acylation with 2‐bromopropionyl bromide provides an iterative two‐step divergent growth approach to the synthesis of a new class of poly(thioglycerol‐2‐ propionate) (PTP) dendrimers. In this article, the addition of a third step, the single‐electron transfer living radical polymerization (SET‐LRP) of methyl acrylate (MA), was shown to provides access to a three‐step “branch” and “grow” divergent approach to dendritic macromolecules wherein poly(methyl acrylate) (PMA) connects the branching subunits. This facile methodology can provide a diversity of dendritic macromolecular topologies and will ultimately provide the means to the development of self‐organizable dendritic macromolecules. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3940–3948, 2009
Synthesis of dendrimers through divergent iterative thio‐bromo “Click” chemistry
Authors: Rosen Brad M. , Lligadas Gerard , Hahn Christian , Percec Virgil 
Published: June 2009

AbstractThe development of a novel nucleophilic thio‐bromo “Click” reaction, specifically base‐mediated thioetherification of thioglycerol with α‐bromoesters, is reported. Combination of this thio‐bromo click reaction with subsequent acylation with 2‐bromopropionyl bromide provides an iterative two‐step divergent growth approach to the synthesis of a new class of poly(thioglycerol‐2‐propionate) (PTP) dendrimers. This approach is demonstrated in the rapid preparation of four generation (G1–G4) of PTP dendrimers with high‐structural fidelity. The isolated G1–G4 bromide‐terminated dendrimers can be used directly as dendritic macroinitiators for the synthesis of star‐polymers via SET‐LRP. Additionally, the intermediate hydroxy‐terminated dendrimers are analogs of other water‐soluble polyester and polyether dendrimers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3931–3939, 2009
Effect of molecular weight of macro‐iniferter on electro‐optical properties of polymer dispersed liquid crystal films prepared by iniferter polymerization
Authors: Yan Bin , He Jie , Du Xin , Qin Ailin , Zhang Qin , Wang Yinghan 
Published: June 2009

AbstractPolymer dispersed liquid crystal (PDLC) films were prepared by a devised method, in which photo‐polymerization induced phase separation in a mixtures of a macro‐iniferter, methyl acrylater, and liquid crystal. The morphology of the obtained PDLC films was examined on a polarized optical microscopy, and the effect of molecular weight of MIs on the electro‐optical properties was deliberately investigated. Decreasing the molecular weight of MIs in the films led to formation of larger liquid crystal droplets and a lower Vth values. Vsat increased and the memory effect decreased because of the increased interface anchoring strength induced by the higher molecular weight of polymer matrices. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1530–1534, 2009
The effects of melt annealing and counterpart's molecular weight on the thermal properties and phase morphology of poly(L‐lactide)‐based blends
Authors: Chiu Fang‐Chyou , Kan Chin‐Yu , Yang Jen‐Chang 
Published: June 2009

AbstractThe thermal properties and phase morphology of poly(L‐lactide) (PLLA)‐based blends have been studied. Two poly(ethylene glycol)s (PEGs) with molecular weight (MW) of about 1,500 (1.5k) g/mol and 2,000,000 (2M) g/mol, respectively, were used as counterparts. The blends were annealed at a preselected temperature of 200 °C for either 2 min or 30 min before the characterizations. Both PEGs were determined to enhance the crystallizability of PLLA. After a 2‐min process of annealing, the PEG(1.5k)'s crystallization efficiency on PLLA has been noted to increase with the increase of its content. Conversely, PEG(2M)'s crystallization efficiency declined with the increase of its content. Extending the annealing time has evidently changed the PEGs' crystallization effect on PLLA. Moreover, the PEG(1.5k) has, to a greater extent, brought about the depression of PLLA's melting temperature by increasing its content, and this depression increased with the annealing time. The blends exhibited lower thermal stability than those of the parent components, particularly for the PEG(1.5k)‐included system with a higher PEG content. Regardless of the annealing time, the PEG(1.5k)‐included blends have shown homogeneous melt morphology under light microscope, whereas the PEG(2M)‐included blends have displayed phase‐separated melt morphology. In addition to the composition, PEG's MW and annealing time influence the crystalline morphology of the blends. The ringed PLLA spherulites have appeared mostly in the 2‐min annealed PEG(1.5k)‐included blends. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1497–1510, 2009
Effective in situ synthesis and characteristics of polystyrene nanoparticle‐covered multiwall carbon nanotube composite
Authors: Patole Archana S. , Patole S. P. , Yoo Ji‐Beom , Ahn Jeong‐Ho , Kim Tae‐Ho 
Published: June 2009

AbstractThe higher surface area of selectively grown multiwall carbon nanotubes (MWCNTs) and the better proximity of the reactant species in in situ microemulsion polymerization were used to attach the polystyrene (PS) nanoparticles to the outer wall of MWCNTs. Attachment were achieved by replacing surfactant with PS nanoparticles. SEM showed that the MWCNTs and PS nanoparticles were distributed in the composite. High resolution transmission electron microscopy showed successful anchoring of PS nanoparticles to the outer wall of the MWCNTs. In addition, anchoring enhanced the Raman's G/D ratio of the MWCNT and degradation temperature in PS nanoparticles. A mechanism of attachment of PS nanoparticles on the outer wall of MWCNT was proposed. The modified MWCNTs exhibited good durability and dispersability in different organic solvents. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1523–1529, 2009
A potential low‐rate DoS attack against network firewalls
Authors: Salah K. , Sattar K. , Sqalli M. , Al‐Shaer Ehab 
Published: June 2009

AbstractIn this paper we identify a potential Denial of Service (DoS) attack that targets the last‐matching rules of the security policy of a firewall. The last‐matching rules are those rules that are located at the bottom of the ruleset of a firewall's security policy, and would require the most processing time by the firewall. If these rules are discovered, an attacker can potentially launch an effective low‐rate DoS attack to trigger worst‐case or near worst‐case processing, thereby overwhelming the firewall and bringing it to its knees. In this paper, we present a probing technique to remotely discover the last‐matching rules of a firewall. We study experimentally the effectiveness of this probing technique taking into account important factors such as the firewall's motherboard architecture and load conditions at network links and hosts. In addition we examine the impact of launching a low‐rate DoS attack on a firewall's performance. The performance is studied in terms of the firewall's CPU utilization and throughput, packet loss, and latency. Copyright © 2009 John Wiley & Sons, Ltd.
Investigation of transfer film of PTFE/bronze composites on 2024Al surface
Authors: Wang Yunxia , Wang Hongling , Yan Fengyuan 
Published: June 2009

AbstractPolytetrafluoroethylene (PTFE) composites filled with 10–30% volume content of bronze powder were prepared through molding and sintering process. Transfer films of these composites were prepared on surface of 2024 Al bar through friction method under certain condition. Roughness, morphology, andelement of these transfer films were investigated using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) methods. Tribological propertiesof these transfer films sliding against GCr15 steel ball were tested using a DFPM reciprocating tribometer. Worn surfaces were observed and analyzed using SEM and EDS methods. It was found that uniformity and continuity of the transfer films were obviously improved by the increase of bronze content of the composites. Transfer films with better uniformity and continuity holds longer wear life. Considerably lower friction coefficient and longer wear life of these transfer films indicate that the transfer films prepared in the experiment could effectively prevent direct contact of metal friction pair and thus protect them from heavy wear. SEM and EDS analyses of the worn surfaces indicate that adhesion wear and fatigue wear were main wear modes of the transfer film. Copyright © 2009 John Wiley & Sons, Ltd.
c‐Fos expression associated with reinstatement of cocaine‐seeking behavior by response‐contingent conditioned cues
Authors: Kufahl Peter R. , Zavala Arturo R. , Singh Akanksha , Thiel Kenneth J. , Dickey Erin D. , Joyce Jeffrey N. , Neisewander Janet L. 
Published: June 2009

AbstractThe capability of cocaine cues to generate craving in cocaine‐dependent humans, even after extended abstinence, is modeled in rats using cue reinstatement of extinguished cocaine‐seeking behavior. We investigated neural activity associated with incentive motivational effects of cocaine cues usingc‐fosmRNA and Fos protein expression as markers. Unlike preceding studies, we used response‐contingent presentation of discrete cues to elicit cocaine seeking. Rats were first trained to press a lever, resulting in cocaine reinforcement and light and tone cues. Rats then underwent extinction training, during which lever presses decreased. On the test day, rats either received response‐contingent cocaine cues or received no cues. The cues reinstated extinguished cocaine‐seeking behavior on the test day. In general, cue‐elicitedc‐fosmRNA and protein expression were similar and both were enhanced in the prefrontal cortex, ventral tegmental area (VTA), dorsal striatum, and nucleus accumbens. Cues elicited more widespread Fos protein expression relative to our previous research in which cues were presented noncontingently without prior extinction training, including increases in the VTA, substantia nigra, ventral subiculum, and lateral entorhinal cortex. We also observed a correlation between cocaine‐seeking behavior and Fos in the agranular insula (AgI) and basolateral amygdala (BLA). The findings suggest that connections between BLA and AgI play a role in cue‐elicited incentive motivation for cocaine and that reinstatement of cocaine seeking by response‐contingent cues activates a similar corticolimbic circuit as that observed with other modes of cue presentation; however, activation of midbrain and ventral hippocampal regions may be unique to reinstatement by response‐contingent cues. Synapse 63:823–835, 2009. © 2009 Wiley‐Liss, Inc.
Building International Collaborative Capacity: Contributions of Community Psychologists to a European Network
Authors: García-Ramírez Manuel , Paloma Virginia , Suarez-Balcazar Yolanda , Balcazar Fabricio 
Published: June 2009

AbstractEurope is in the process of building a more participative, just, and inclusive European Union.The European Social Fund, which is an initiative developed to actively promote multinational partnerships that address pressing social issues, is a good example of the European transformation. This article describes the steps taken to develop and evaluate the activities of an international network promoting collaborative capacity among regional partners involved in the prevention of labor discrimination toward immigrants in three European countries—Spain, Belgium, and Italy. An international team of community psychologists proposed an empowering approach to assess the collaborative capacity of the network. This approach consisted of three steps: (1) establishing a collaborative relationship among partners, (2) building collaborative capacity, and (3) evaluating the collaborative capacity of the network. We conclude with lessons learned from the process and provide recommendations for addressing the challenges inherent in international collaboration processes.
Scale‐up of Enzyme‐Assisted Aqueous Extraction Processing of Soybeans
Authors: de Moura Juliana Maria Leite Nobrega , de Almeida N. M. , Johnson L. A. 
Published: June 2009

AbstractThe effects of scaling‐up enzyme‐assisted aqueous extraction process (EAEP) using 2 kg of flaked and extruded soybeans as well as the effects of different extrusion and extraction conditions were evaluated. Standard single‐stage EAEP at 1:10 solids‐to‐liquid ratio (SLR) was used to evaluate the effects of different extruder screw speeds and whether or not collets were extruded directly into water. Increasing extruder screw speed from 40 to 90 rpm improved oil extraction yield from 85 to 95%. Oil, protein, and solids extraction yields of 97, 86, and 78% were obtained when extruding directly into water and 95, 84, and 77% when not extruding into water. When not extruding into water, standard single‐stage EAEP (1:10 SLR) yielded 95, 84, and 77% of total oil, protein, and solids extraction, respectively, and two‐stage countercurrent EAEP (1:6 SLR) yielded 99, 94, and 83% total oil, protein, and solids extraction, respectively. These yields were similar to those previously obtained in the laboratory (0.08 kg soybeans), but higher oil contents were observed in the skim fractions produced at pilot‐plant scale for both processes. Modifying processing parameters improved the oil distribution among the fractions, increasing oil yield in the cream fraction (from 76 to 86%) and reducing oil yield in the skim fraction (from 23 to 12%). Steady‐state oil extraction was achieved after two 2‐stage extractions. Two‐stage countercurrent EAEP is particularly attractive due to reduced water usage compared to conventional single‐stage extraction.