bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on curing kinetics and thermal behavior of phosphorylated epoxy resin in the presence of aromatic amide‐amines
Authors: Durga Geeta , Kukreja Parveen , Narula A. K. 
Published: July 2010

AbstractThis article describes the synthesis of some novel aromatic amide‐amine curing agents by reacting 1 mole of p‐amino benzoic acid with 1 mole of each of 1,4‐phenylene diamine (P), 1,5‐diamino naphthalene (N), 4,4′‐(9‐fluorenyllidene)‐dianiline (F), 3,4′‐oxydianiline (O), and 4,4′‐diaminodiphenyl sulphide (DS) and were designated as PA, NA, FA, OA, and SA, respectively. The aromatic amide‐amines so synthesized were characterized with the help of spectroscopic techniques, viz., Fourier Transform Infrared, proton nuclear magnetic resonance, and carbon nuclear magnetic resonance. The curing kinetics of the epoxy resins obtained by reacting amines with diglycidyl ether of bisphenol‐A blended with tris(glycidyloxy)phosphine oxide in a ratio of 3 : 2, respectively, were investigated by DSC technique using multiple heating rate method (5, 10, 15, 20°C/min). Activation energies were determined by fitting the experimental data into Kissinger and Flynn‐Wall‐Ozawa Kinetic models. The activation energies obtained through Flynn‐Wall‐Ozawa method were slightly higher than Kissinger method but were comparable. However, both the energies were found to be dependent on the structure of amines. The thermal stability and weight loss behavior of isothermally cured thermosets were also investigated using thermogravimetric analysis in nitrogen atmosphere. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of polyacrylonitrile via ARGET ATRP using CCl4 as initiator
Authors: Zong Guangxi , Chen Hou , Wang Chunhua , Liu Delong , Hao Zhihai 
Published: July 2010

AbstractActivators regenerated by electron transfer (ARGET) for atom transfer radical polymerization (ATRP) of acrylonitrile (AN) was investigated using carbon tetrachloride (CCl4) as initiator, ferric trichloride anhydracs (FeCl3)/iminodiacetic acid (IDA) as catalyst system, L‐ascorbic acid (VC) as reducing agent, and N,N‐dimethylformamide (DMF) as solvent. Kinetic data of polymerization demonstrated the features of living/controlled free‐radical polymerization. The conversion of AN increased with the increasing concentration of CCl4, [FeCl3]/[IDA] catalyst system and VC. The molecular weight decreased with the increasing concentration of CCl4, [FeCl3]/[IDA] catalyst system and VC. The value of polydispersity index (PDI) increased with the increasing concentration of [FeCl3]/[IDA] catalyst system and VC, while the value of PDI decreased first and then increased with the increasing concentration of CCl4 and IDA. 1H‐NMR spectra of PAN further verified the features of living/controlled free radical polymerization of AN. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of processing conditions and physicochemical interactions on morphology and fracture behavior of a clay/thermoplastic/thermosetting ternary blend
Authors: Hernandez M. , Duchet‐Rumeau J. , Sautereau H. 
Published: July 2010

AbstractThis study provides information on the mechanical behavior of epoxy‐poly(methyl methacrylate) (PMMA)‐clay ternary composites, which have been prepared using the phase separation phenomenon of PMMA and the introduction of organophilic‐modified montmorillonites (MMTs), the continuous matrix being the epoxy network. Two dispersion processing methods are used: a melt processing without any solvent and an ultrasonic technique with solvent and a high‐speed stirrer. TEM analysis shows that phase separation between PMMA and the epoxy network was obtained in the shape of spherical nodules in the presence of the clay in both process methods used. Nanoclay particles were finely dispersed inside thermosetting matrix predominantly delaminated when ultrasonic blending was used; whereas micrometer‐sized aggregates were formed when melt blending was used. The mechanical behavior of the ternary nanocomposites was characterized using three‐point bending test, dynamic mechanical analysis (DMA), and linear elastic fracture mechanics. The corresponding fracture surfaces were examined by scanning electron microscopy to identify the relevant fracture mechanisms involved. It was evidenced that the better dispersion does not give the highest toughness because ternary nanocomposites obtained by melt blending present the highest fracture parameters (KIc). Some remaining disordered clay tactoids seem necessary to promote some specific toughening mechanisms. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Thermally stimulated depolarization study in polyvinylidenefluoride–polysulfone polyblend films
Authors: Saxena Pooja , Gaur M. S. 
Published: July 2010

AbstractThermally stimulated depolarization currents (TSDCs) in short‐ and open‐circuit modes in polyvinylidenefluoride (PVDF)–polysulfone (PSF) polyblend have been recorded. The TSDC thermograms of PVDF and PSF in short‐circuit mode show two peaks, whereas the polyblend of the two polymers shows a single peak. With the increase in PSF weight percentage in the polyblend, the magnitude of TSDC peak current increased and the peak current position shifted toward the lower temperature side. The single peak in polyblend appears at 165°C ± 10°C, which is at higher temperature than the temperature of low‐temperature peak for individual polymers. This suggests that this peak may be due to dipolar polarization. Subsequently, shifting of peak toward higher temperature side with increase in polarizing temperature indicates the space charge peak. This contradiction has been explained on the basis of induced dipole theory. The behavior of short circuit TSDC could be explained in terms of the heterocharge caused by dipole orientation and ionic homocharge drift, together with the injection of charge carriers from electrodes and their subsequent localization in surface and bulk traps. However, two oppositely directed TSDC peaks observed in open‐circuit mode in all the polyblend samples could be considered as the result of superposition of two overlapped and oppositely directed peaks, one caused by relaxation of dipole polarization and the other by the space charge. Thus, we have compared TSDC measured in open‐ and short‐circuit modes to distinguish between these two relaxation processes and separate them. There is only one broad peak observed in the short‐circuit mode of the polyblend, which entirely corresponds to the relaxation of dipole polarization. Insertion of a dielectric gap in the open‐circuit mode does not affect the dipole current, but the space charge component flowing in the opposite direction is added to the former. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Morphology, thermal and mechanical properties of the polyhedral oligomeric silsesquioxane side‐chain epoxy hybrid material
Authors: Chiu Yie‐Chan , Chou I‐Chen , Tsai Hsieh‐Chih , Riang Linawati , Ma Chen‐Chi M. 
Published: July 2010

AbstractThe side‐chain polyhedral oligomeric silsesquioxane (POSS)‐type epoxy (IPEP) hybrid material was synthesized, and the particle sizes of the POSS segment were less than 5 nm and which particles dispersed uniformly. The 3D AFM microphotograph of the IPEP/DGEBA (diglycidyl ether of bisphenol A) hybrid material exhibited the unique “island” shape, and their XRD pattern displayed amorphous halo structure. The POSS segments of the IPEP could improve the thermal degradation activation energies. Additionally, introduction of the IPEP into the DGEBA could improve the char yield and provide the antioxidation property in the air atmosphere. The char yields of the IPEP/DGEBA hybrid materials could improve from 14.48 to 19.21% and from 0.18 to 1.17% in the nitrogen and air atmospheres, respectively. The IPEP segments could also improve the hardness when the IPEP contents of the IPEP/DGEBA hybrid materials were less than 50 wt %. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Innovation, sustainability and regional development: the Nelson/Marlborough seafood cluster, New Zealand
Authors: Pavlovich Kathryn , Akoorie Michèle 
Published: July 2010

AbstractThis paper explores how innovation, developed through multi‐sector partnerships within a regional context, has assisted in increasing the sustainability of the New Zealand fishery industry. Qualitative data were collected from a single regional cluster, the Nelson/Marlborough seafood industry, located in the upper South Island – the largest seafood region in New Zealand. This context is unique in that New Zealand controls the world's fourth largest coastal fishing zone, with a 200‐mile exclusive economic fishing zone (EEZ) established in 1978, and has one of the world's most innovative quota management systems. Analysis of the qualitative interview data demonstrated that: (1) collaboration among core firms was primarily at the product and process level, generally to improve the productivity of the firm; (2) opportunities for new sector growth were available from related industry collaboration; and (3) multi‐sector collaborations involving both core firms and social infrastructure contributed more significantly to sustainable strategic outcomes. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Two New Furanoeremophilanes from Senecio santelisis
Authors: Arias Cassará María L. , Borkosky Susana A. , Sierra Manuel González , Bardón Alicia , Ybarra María I. 
Published: July 2010

AbstractFrom an Argentine collection of Senecio santelisis Phil., the new furanoeremophilanoids, (10βH)‐6β‐acetoxy‐1α‐hydroxyfuranoeremophilan‐9‐one (1) and (10βH)‐1α‐hydroxy‐6β‐(propanoyloxy)furanoeremophilan‐9‐one (2), together with the known (10αH)‐6β‐acetoxy‐1α‐hydroxyfuranoeremophilan‐9‐one (3), (10αH)‐1α,6β‐diacetoxyfuranoeremophilan‐9‐one (4), and (10αH)‐1α‐hydroxy‐6β‐(propanoyloxy)furanoeremophilan‐9‐one (5) were isolated. Their structures and relative configurations were established on the basis of spectroscopic analysis. CHCl3 Extract and pure compounds were evaluated for their antifungal activity. Compound 5 exhibited remarkable mycelial growth inhibition against B. cinerea with an IC50 value of 21.4 μg/ml.
Insecticidal Constituents from the Argentine Liverwort Plagiochila bursata
Authors: Ramírez Marta , Kamiya Norma , Popich Susana , Asakawa Yoshinori , Bardón Alicia 
Published: July 2010

AbstractThe new 2,3‐secoaromadendrane 1, together with the known compounds plagiochilines A and M (2 and 3, resp.), fusicogigantone A (4), and 1,4‐dimethylazulene (5) were isolated from an Argentine collection of the liverwort Plagiochila bursata. Structures were elucidated by extensive 1D‐ and 2D‐NMR studies. Compounds 2 and 4, incorporated to the larval diet at 100 μg per g of diet, reduced the larval growth of Spodoptera frugiperda (Lepidoptera: Noctuidae) by 66±29% and 25±8% and produced 55 and 75% larval mortality at early instars and 20 and 25% pupal mortality, respectively. Treatment with compound 2 also produced abdomen and wing malformation in adults leading to impossibility to mate.
Antimicrobial Activity of Rosmarinus officinalis against Oral Pathogens: Relevance of Carnosic Acid and Carnosol
Authors: Bernardes Wagner A. , Lucarini Rodrigo , Tozatti Marcos G. , Souza Maria G. M. , Andrade Silva Márcio L. , da Silva Filho Ademar A. , Martins Carlos H. Gomes , Miller Crotti Antonio E. , Pauletti Patricia M. , Groppo Milton , Cunha Wilson R. 
Published: July 2010

AbstractThe in vitro inhibitory activity of crude EtOH/H2O extracts from the leaves and stems of Rosmarinus officinalis L. was evaluated against the following microorganisms responsible for initiating dental caries: Streptococcus mutans, S. salivarius, S. sobrinus, S. mitis, S. sanguinis, and Enterococcus faecalis. Minimum inhibitory concentrations (MIC) were determined with the broth microdilution method. The bioassay‐guided fractionation of the leaf extract, which displayed the higher antibacterial activity than the stem extract, led to the identification of carnosic acid (2) and carnosol (3) as the major compounds in the fraction displaying the highest activity, as identified by HPLC analysis. Rosmarinic acid (1), detected in another fraction, did not display any activity against the selected microorganisms. HPLC Analysis revealed the presence of low amounts of ursolic acid (4) and oleanolic acid (5) in the obtained fractions. The results suggest that the antimicrobial activity of the extract from the leaves of R. officinalis may be ascribed mainly to the action of 2 and 3.
A Novel Dimeric Coumarin Analog and Antimycobacterial Constituents from Fatoua pilosa
Authors: Chiang Chun‐Ching , Cheng Ming‐Jen , Peng Chien‐Fang , Huang Hung‐Yi , Chen Ih‐Sheng 
Published: July 2010

AbstractOne novel dimeric coumarin analog, fatouapilosin (1), together with 18 known compounds, have been isolated from the whole plants of Fatoua pilosa. The structures of these isolates were elucidated by means of spectroscopic techniques (UV, IR, MS, 1H‐ and 13C‐NMR, DEPT, COSY, NOESY, HSQC, HMBC, and MS analyses). Among the tested compounds 2–14, scopoletin (3), isobavachalcone (12), and (E)‐1‐[2,4‐dihydroxy‐3‐(3‐methylbut‐2‐enyl)phenyl]‐3‐(2,2‐dimethyl‐8‐hydroxy‐2H‐benzopyran‐6‐yl)prop‐2‐en‐1‐one (14) exhibited the strongest antimycobacterial activities against Mycobacterium tuberculosis H37Rv, with MIC values of 42, 18, and 30 μg/ml, respectively.
Variation in Volatile Leaf Oils of Eleven Eucalyptus Species Harvested from Korbous Arboreta (Tunisia)
Authors: Elaissi Ameur , Medini Hanène , Larbi Khouja Mohamed , Simmonds Monique , Lynene Fréderic , Farhat Farhat , Chemli Rachid , Harzallah‐Skhiri Fethia 
Published: July 2010

AbstractHydrodistillation of the dried leaves of eleven species of the genus Eucalyptus L'Hér., i.e., E. astringens Maiden, E. camaldulensis Dehnh., E. diversifolia Bonpl., E. falcata Turcz., E. ficifolia F. Muell., E. gomphocephala DC., E. lehmannii (Schauer) Benth., E. maculata Hook., E. platypus Hook., E. polyanthemos Schauer, and E. rudis Endl., harvested from Korbous arboreta (region of Nabeul, northeast of Tunisia) in April 2006, afforded essential oils in yields varying from 0.1±0.1 to 3.8±0.1%, dependent on the species. E. astringens and E. ficifolia showed the highest and the lowest mean percentage of essential oil amongst all the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 138 components, representing 74.0 to 99.1% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8‐cineole, followed by trans‐pinocarveol (1), spathulenol (2), α‐pinene, p‐cymene, (E,E)‐farnesol, cryptone, globulol (3), β‐phellandrene, α‐terpineol, viridiflorol, and α‐eudesmol. The principal‐component and the hierarchical‐cluster analyses separated the eleven Eucalyptus leaf essential oils into seven groups, each constituting a chemotype.
Effect of Controlled Crossing on the Triglyceride and Fatty Acid Composition of Virgin Olive Oils
Authors: Dabbou Samia , Rjiba Imed , Echbili Adel , Gazzah Noureddine , Mechri Beligh , Hammami Mohamed 
Published: July 2010

AbstractOur study reports the triglyceride (triacylglycerol, TAG) composition of five new Tunisian virgin olive oil cultivars obtained through controlled crossings of the cultivar (cv.) Chemlali Sfax. These cultivars have been selected among a progeny of 500 olive descendants, based on an evaluation of the fatty‐acid (FA) composition of their oils. Among these samples, two were derived from the crossing with the cv. Sigoise as pollinator (SM634) or pollen acceptor (SM1110) and the others from the crossing with the cv. Meski as pollen acceptor (SM513, SM514, and SM517). The five descendants were characterized by a good fat value, a balanced FA composition, and a high content of triolein, varying between 26.9 (SM514) and 45.46% (SM1110). They had an improved FA composition as compared to that of the cv. Chemlali Sfax and their fruits were slightly bigger. The principal component analysis suggested that the TAG variables were more suitable than the total FAs for an optimum classification of the cultivar samples analyzed. The cultivars obtained through the crossing with the cv. Sigoise (as pollen acceptor or pollinator) had a more favorable composition of FAs and TAG than those obtained through the crossing with the cv. Meski, which indicated that genetic factors had the most important influence on the quality of the virgin olive oils.
ent‐Kaurene Diterpenoids from Blepharispermum hirtum
Authors: Fatope Majekodunmi O. , Varma Gouri B. , Alzri Nasser M. , Marwah Ruchi G. , Nair Rani S. 
Published: July 2010

AbstractThe twigs and leaves of Blepharispermum hirtum Oliver (Asteraceae) were investigated for their larvicidal and antimicrobial activity. Fractionation of the extracts of the twigs, directed by brine shrimp test and antibacterial activities, led to the isolation of compounds 1–4; two of which are new ent‐kaurene diterpenoids, blepharispins A and B (1 and 2, resp.). The structures of compounds 1 and 2 were established from spectral data. The absolute configuration at C(15) in 1 was inferred from Mosher ester analysis and relative configurations were suggested by a NOESY experiment. Compound 4 was significantly larvicidal to newly hatched naupleii of Artemia salina L. (BST LC50=1.3 (3.7–0.0) μg/ml), but the blepharispins were not (BST LC50>500 μg/ml). Nevertheless, compound 1 inhibited the growth of Staphylococcus aureus and Bacillus subtilis at a MIC value of 62.5 μg/ml. The significance of the bioactivity results and the presence of ent‐kaurene diterpenoids in B. hirtum are discussed from biosynthetic and local utilization viewpoints.
How to Spoil the Taste of Insect Prey? A Novel Feeding Deterrent against Ants Released by Larvae of the Alder Leaf Beetle, Agelastica alni
Authors: Hilker Monika , Häberlein Christopher , Trauer Ute , Bünnige Martina , Vicentini Mark‐Oliver , Schulz Stefan 
Published: July 2010

AbstractChemical defense of leaf beetle larvae (Chrysomelidae) against enemies is provided by secretions containing a wide range of deterrent compounds or by unpalatable hemolymph constituents. Here we report a new, very strong feeding deterrent against ants released by larvae of the alder leaf beetle Agelastica alni when attacked. The larvae release a defensive fluid from openings of pairwise, dorsolaterally located tubercles on the first to the eighth abdominal segments. The fluid, consisting of hemolymph and probably a glandular cell secretion, has previously been shown to contain a very stable, non‐volatile feeding deterrent. The major deterrent component was isolated by repeated HPLC separation and analyzed by NMR and MS. The compound proved to be γ‐L‐glutamyl‐L‐2‐furylalanine (1), a novel dipeptide containing the unusual amino acid L‐2‐furylalanine. This amino acid, although synthetically well known, has not previously been reported from natural sources. The absolute configuration of the natural compound was elucidated by enantioselective gas chromatography after derivatization. The structure of the dipeptide was verified by the synthesis of several isomeric dipeptides. In bioassays a concentration of 1 μg μL−1 was sufficient to deter polyphagous Myrmica rubra ants from feeding.
Low‐Temperature Alkane CH Bond Activation by Zeolites: An In Situ Solid‐State NMR H/D Exchange Study for a Carbenium Concerto
Authors: Haouas Mohamed , Fink Gerhard , Taulelle Francis , Sommer Jean 
Published: July 2010

AbstractIsotopic H/D exchange has been monitored by in situ MAS NMR spectroscopy of 2‐[D14]methylpentane with H‐USY to probe the controversy over the alkane conversion mechanism. The probe molecule has distinct exchangeable sites with different accessibility to the zeolite surface. In the early stages of the process, the regioselectivity of exchange demonstrates that the slow step of the mechanism is controlled by a carbenium ion intermediate. At a later stage of exchange, intramolecular hydride migrations, typical of carbenium chemistry, replace D by H also on other carbon atoms, resulting in a loss of regioselectivity. Therefore, the first and the subsequent steps of the H/D exchange proceed at this temperature through a carbenium intermediate species.
Improving handoff efficiency by IS‐FMIPv6 based on IEEE 802.21
Authors: Wu Tin‐Yu , Chen Wei , Lee Wei‐Tsong , Huang Yong‐Ping 
Published: July 2010

SUMMARYThe Media‐Independent Handover (MIH) standard proposed by IEEE 802.21 can reduce handoff delay when mobile nodes switch between heterogeneous access networks and help Mobile Nodes (MNs) roam seamlessly. The MIH standard is suitable for not only heterogeneous networks but also homogeneous networks. According to the Fast Mobile IPv6 (FMIPv6), during handover initiation, for MNs to get new Access Router (nAR's) prefixes, using Router Solicitation for Proxy Advertisement (RtSolPr)/Proxy Router Advertisement (PrRtAdv) may be time consuming. If there are additional quality of service requirements, the FMIPv6 would require much more time. Based on FMIPv6, this paper proposes a new IS‐FMIPv6, which combines MIH services. We also propose a new mechanism for discovering the access route. This scheme reduces the time spent for finding the route to the nAR and increases the probability that FMIPv6 operates in the predictive mode by reducing initiation handoff delay. Published in 2010 by John Wiley & Sons, Ltd.
Reduction of NO by CO on Unsupported Ir: Bridging the Materials Gap
Authors: Chen Wenhua , Shen Quantong , Bartynski Robert A. , Kaghazchi Payam , Jacob Timo 
Published: July 2010

AbstractTemperature programmed desorption (TPD) and density functional theory (DFT) are used to investigate adsorption sites and reaction of coadsorbed NO and CO on planar Ir(210) and faceted Ir(210) with tailored sizes of three‐sided nanopyramids exposing (311), (31${\bar 1}$) and (110) faces. Both planar and faceted Ir(210) are highly active for reduction of NO by CO with high selectivity to N2, which is accompanied by simultaneous oxidation of CO. Evidence is found for structure sensitivity in adsorption sites and reaction of coadsorbed NO and CO on faceted Ir(210) versus planar Ir(210). Strong interaction between NO and CO at high NO exposure and one‐monolayer CO pre‐coverage results in “explosive” evolution of N2 and CO2 on planar Ir(210) and size effects in reduction of NO by CO on faceted Ir(210) for average facet size ranging from 5 to 14 nm without change in facet structure.
Sexually distinct development of vocal pathways in Xenopus laevis
Authors: Yamaguchi Ayako , Muñoz Martha M. , Bose Tina O. , Oberlander Joseph G. , Smith Shane 
Published: July 2010

AbstractDeterministic rules, rather than experience, are thought to regulate the development of simple behaviors in vertebrates and invertebrates. We revisited this issue through examination of the sexually distinct vocalizations of African clawed frogs (Xenopus laevis), a reproductive behavior used by sexually mature males and females. We discovered that, as expected for simple behavior, female vocalizations develop through deterministic rules. The rare calls of juvenile females are indistinguishable from those of adult females. The vocal pathways of juvenile females, as measured by the contractile properties of the laryngeal muscles (the vocal muscles) and the laryngeal motoneuron somata (vocal motoneurons) size, are the developmental default and do not differentiate as they mature. Male Xenopus, in contrast, produce extensive vocalizations with rudimentary acoustic structure before reaching sexual maturity. Moreover, the functional properties of the vocal central pattern generator mature before muscle fibers and motoneuron size are fully masculinized. The results suggest that neuronal activity during development may be important in organizing the contractile properties of the muscle fibers in male, but not in female Xenopus. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 862–874, 2010