bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of fluorescence end‐labeled polystyrene via reversible addition‐fragmentation chain transfer (RAFT) polymerization
Authors: Zhou Di , Zhu Xiulin , Zhu Jian , Cheng Zhenping 
Published: August 2008

AbstractFluorescence end‐labeled polystyrene (PS) with heteroaromatic carbazole or indole group were prepared conveniently via reversible addition‐fragmentation chain transfer (RAFT) polymerization using dithiocarbamates, ethyl 2‐(9H‐carbazole‐9‐carbonothioylthio)propanoate (ECCP) and benzyl 2‐phenyl‐1H‐indole‐1‐carbodithioate (BPIC) as RAFT agents. The end functionality of obtained PS with different molecular weights was high. The steady‐state and the time‐resolved fluorescence techniques had been used to study the fluorescence behaviors of obtained end‐labeled PS. The fluorescence of dithiocarbamates resulting PS in solid powder cannot be monitored; however, they exhibited structured absorptions and emissions in solvent DMF and the fluorescence lifetimes of PS had no obvious change with molecular weights increasing. These observations suggested that the polymer chains were possibly stretched adequately in DMF, that is, the fluorescence end group was exposed into solvent molecules and little quenching of excited state occurred upon incorporation into polymer chain. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6198–6205, 2008
Thermal recordable novel cholesteric liquid crystalline polyacrylates containing various chiral moieties
Authors: Liu Jui‐Hsiang , Hung Hsien‐Jung , Yang Po‐Chih , Tien Kai‐Hsin 
Published: August 2008

AbstractTo investigate the effect of spacer length and linkages between the rigid mesogenic core and the terminal group on the molecular interaction and physical properties of polymers, two series of novel side chain liquid crystalline polyacrylates were synthesized. These were composed of liquid crystalline monomers with six or eleven methylene segments as spacers, and chiral monomers end capped with menthyl or cholesteryl groups. Liquid crystalline phases of the polymers were investigated using differential scanning calorimetry and polarized optical microscopy, and confirmed with X‐ray diffractometry. Color image recording of the synthesized polymer films was achieved using a thermal treatment, and then fixed by quenching. This investigation demonstrates that the introduction of carbonate linking groups between the rigid mesogenic core and terminal group decreases both the lateral molecular interaction and thermal stability of the liquid crystalline polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6214–6228, 2008
Thermal treatment of dense polyimide membranes
Authors: Duthie X. , Kentish S. , Pas S. J. , Hill A. J. , Powell C. , Nagai K. , Stevens G. , Qiao G. 
Published: August 2008

AbstractA study has been conducted to clarify the relationship between polymer structure, annealing temperature, and the extent of plasticization by high‐pressure CO2 for two typical polyimide membranes; BTDA‐DAPI (poly(3,3′‐4,4′‐benzophenone tetracarboxylic–dianhydride diaminophenylindane) and 6FDA‐TMPDA (poly(2,2′‐bis(3,4′‐dicasrboxyphenyl) hexafluoropropane dianhydride–2,3,5,6‐tetramethyl‐1,4‐phenylenediamine). Both membrane materials are exposed to varying levels of thermal annealing at 200 and 250 °C. The effect of this heat treatment on free volume is examined using positron annihilation lifetime spectroscopy (PALS), whereas fluorescence spectroscopy is used to monitor changes in electronic structure. Results show that thermal annealing causes a reduction in both the size and number of free volume elements. A strong relationship is found between the fluorescence peak intensity for 6FDA‐TMPDA and both the membrane gas permeability and plasticization pressure. This correlation is most likely the result of the formation of charge transfer complexes, particularly at 250 °C. However, the formation of covalent crosslinks at these temperatures cannot be discounted. No fluorescence is observed for BTDI‐DAPI. Although thermal annealing has a significant effect on the extent of plasticization in both polymers, it is found that the rate of plasticization is unaffected by the annealing temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1879–1890, 2008
Characterization of the stable and metastable poly(ethylene oxide)–urea complexes in electrospun fibers
Authors: Liu Yang , Antaya Hélène , Pellerin Christian 
Published: August 2008

AbstractSolution electrospinning was used for the first time to prepare nanofibers of the stable (α) and metastable (β) complexes between poly(ethylene oxide) (PEO) and urea. Both types of fibers were highly crystalline and presented a large level of molecular orientation. Detailed characterization of the ill‐studied β complex was performed using wide angle X‐ray diffraction (WAXD), infrared spectroscopy, and differential scanning calorimetry (DSC). Results reveal that it possesses a 3:2 PEO:urea stoichiometry and suggest that it belongs to the orthorhombic system with a = 1.907 nm, b = 0.862 nm, and c = 0.773 nm. The PEO chains are oriented along the fiber axis and present a conformation significantly affected by strong hydrogen bonding with urea when compared with the pure polymer and the stable complex. A layered structure model is suggested for the metastable complex, in which the urea molecules would be arranged into a ribbon‐like structure intercalated between two PEO layers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1903–1913, 2008
Synthesis and optoelectronic characterization of poly(fluorenylethynylene)s containing perylene bisimide moiety in the backbone
Authors: Wang Hong‐Yu , Peng Bo , Wei Wei 
Published: August 2008

AbstractA series of poly(fluorenylethynylene)s containing different ratios of perylene bisimide moiety in the backbone were synthesized by Sonogashira cross‐coupling reaction. The electron‐deficient perylene bisimide moiety was introduced into the backbone to construct the donor‐acceptor architectures. The chemical structures of these copolymers were determined by 1H NMR and FTIR. The solubility, thermal, and optoelectronic properties were studied. The results of UV–vis absorption and fluorescence spectra of these copolymers showed that intramolecular energy transfer and charge separation occur between the fluorenyl alkyne segment and perylene bisimide moiety. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1932–1938, 2008
The relationship between chondroprotective and antiinflammatory effects of Withania somnifera root and glucosamine sulphate on human osteoarthritic cartilage in vitro
Authors: Sumantran Venil N. , Chandwaskar Rucha , Joshi Asavari Kulkarni , Boddul Sanjay , Patwardhan Bhushan , Chopra Arvind , Wagh Ulhas V. 
Published: August 2008

AbstractUsing a validated explant model of in vitro cartilage damage, the effects of aqueous extracts of Withania somnifera (Ashwagandha) root and glucosamine sulphate (GlcS) were tested on the levels of nitric oxide (NO) and glycosaminoglycans (GAGs) secreted by knee cartilage from chronic osteoarthritis (OA) patients. W. somnifera extracts significantly decreased NO release by explants from one subset of patients (antiinflammatory response) and significantly increased levels of NO and GAGs released by explants from the second subset (‘non‐responders’). This is the first study showing direct, statistically significant, antiinflammatory effects of W. somnifera on human OA cartilage. It also confirmed that glucosamine sulphate exhibited statistically significant, antiinflammatory and chondroprotective activities in human OA cartilage. However, these beneficial effects of GlcS were observed in cartilage explants from 50% of patients tested (‘responders’). In contrast, glucosamine significantly increased secretion of NO but not GAGs in explants from the second subset of OA patients (‘non‐responders’). Cartilage explants from the 11 OA patients gave differential responses to both drugs. Patient samples which responded to the antiinflammatory effects of W. somnifera did not always give a similar response to glucosamine, and vice versa. Thus, this in vitro model of human cartilage damage provides qualitative and statistically significant, quantitative pre‐clinical data on antiinflammatory and chondroprotective activities of antiarthritic drugs. Copyright © 2008 John Wiley & Sons, Ltd.
Omega‐3 fatty acid deficiency augments amphetamine‐induced behavioral sensitization in adult DBA/2J mice: Relationship with ventral striatum dopamine concentrations
Authors: McNamara Robert K. , Sullivan Juliana , Richtand Neil M. , Jandacek Ronald , Rider Therese , Tso Patrick , Campbell Nick , Lipton Jack 
Published: August 2008

AbstractThe principal polyunsaturated fatty acid acids found in brain, arachidonic acid (AA) and docosahexaenoic acid (DHA), preferentially accumulate in synaptic membranes. Although neurochemical studies have found that dietary‐induced deficits in rat brain DHA composition significantly alter mesocorticolimbic dopamine (DA) neurotransmission, its impact on DA‐mediated behavior remains poorly understood. In the present study, we determined the effects of dietary‐induced deficits in brain DHA composition on amphetamine (AMPH)‐induced locomotor activity and sensitization in DBA/2J mice, an inbred strain previously found to be hyporesponsive to AMPH, as well as monoamine concentrations in the PFC and ventral striatum following the AMPH challenge. Chronic dietary ω‐3 fatty acid deficiency significantly decreased PFC (−25%) and ventral striatum (−20%) DHA composition, increased PFC (+7%) and ventral striatum (+6%) AA composition, and increased the AA:DHA ratio in PFC (+30%) and ventral striatum (+24%). The development and expression of AMPH‐induced sensitization was significantly increased in DHA‐deficient mice, whereas novelty‐ and acute AMPH‐induced locomotor activity were not altered. DHA‐deficient mice exhibited significantly greater ventral striatum, but not PFC, DA and DA metabolite concentrations following the AMPH challenge, whereas serotonin and noradrenalin concentrations were not altered. Ventral striatum AA composition and the AA:DHA ratio were both positively correlated with DA concentrations, and both ventral striatum AA composition and DA concentrations were positively correlated with locomotor activity during the preceding AMPH challenge. These results demonstrate that dietary‐induced brain DHA deficiency, and associated elevation in the AA:DHA ratio, augment AMPH‐induced sensitization in DBA/2J mice, and that this augmented response is associated with selective alterations in the mesolimbic DA pathway. Synapse 62:725–735, 2008. © 2008 Wiley‐Liss, Inc.
Differences in aggressive behavior and in the mesocorticolimbic DA system between A/J and BALB/cJ mice
Authors: Couppis Maria H. , Kennedy Craig H. , Stanwood Gregg D. 
Published: August 2008

AbstractThe neurotransmitters DA and serotonin are known to be important modulators of aggression, but endogenous differences in these systems between aggressive and nonaggressive animals are poorly understood. To examine this issue, the mesocorticolimbic DA and serotonin systems of two mouse strains that differ in aggressive behavior, BALB/cJ and A/J, were analyzed using high performance liquid chromatography and quantitative receptor autoradiography. Significant differences in both serotonergic and dopaminergic systems were found between aggressive and nonaggressive mice. The nonaggressive A/J mice exhibited higher DA utilization in the nucleus accumbens and prefrontal cortex, higher D1 receptor expression in the rostral pole of the accumbens, and lower D2 receptor expression throughout the accumbens, as compared with aggressive BALB/cJ mice. Although correlative in nature, these data suggest that differences in mesocorticolimbic DA and serotonin systems may contribute to endogenous differences in aggression. Synapse 62:715–724, 2008. © 2008 Wiley‐Liss, Inc.
Repeated morphine exposure decreased the nucleus accumbens excitability during short‐term withdrawal
Authors: Heng Li‐Jun , Yang Jing , Liu Yi‐Hui , Wang Wen‐Ting , Hu San‐Jue , Gao Guo‐Dong 
Published: August 2008

AbstractIt is well known that the nucleus accumbens plays an important role in drug reinforcing effect and relapse. However, the cellular neuroadaptations that take place in accumbens neurons after repeated drug exposure are still not well understood, especially for opioids. Here, we examined how nucleus accumbens neuronal excitability becomes affected in rats exposed to morphine using whole‐cell patch‐clamp recordings. Medium spiny neurons recorded from brain slices of repeated morphine treated rats exhibited a significant decrease in the intrinsic excitability after 3–4 days withdrawal, compared to that of neurons from saline treated animals, which was indicated by the increase of current to evoke the first spike and the decrease of spike number induced by depolarizing current steps in the morphine group. Moreover, the excitability decrease was accompanied by related membrane property changes, such as resting membrane potential hyperpolarization, input resistance, and membrane time constant decrease, inward rectification increase, and action potential duration decrease. Taken together, repeated morphine exposure and short‐term withdrawal may reduce nucleus accumbens activity and output by modulating intrinsic membrane properties of its output neurons, which could be an important neuroadaptation process that mediates morphine addictive effect. Synapse 62:775–782, 2008. © 2008 Wiley‐Liss, Inc.
Identification of the orotidine‐5′‐monophosphate decarboxylase gene of the oleaginous yeast Rhodosporidium toruloides
Authors: Yang Fan , Zhang Sufang , Tang Wei , Zhao Zongbao K. 
Published: August 2008

AbstractOleaginous yeast Rhodosporidium toruloides is an excellent microbial lipid producer of great industrial potential, yet there is no effective genetic tool for rationally engineering this microorganism. To develop a marker recycling system, the orotidine‐5′‐monophosphate (OMP) decarboxylase gene of R. toruloides (RtURA3) was isolated using methods of degenerate polymerase chain reaction (PCR) together with rapid amplification of cDNA ends. The results showed that RtURA3 contains four extrons and three introns, and that the encoded polypeptide holds a sequence of 279 amino acid residues with significant homology to those of OMP decarboxylases from other yeasts. A shuttle vector pYES2/CT–RtURA3 was constructed via site‐specific insertion of RtURA3 into the commercial vector pYES2/CT. Transformation of the shuttle vector into Saccharomyces cerevisiae BY4741, a URA3‐deficient yeast strain, ensured the viability of the strain on synthetic dextrose agar plate without uracil, suggesting that the isolated RtURA3 was functionally equivalent to the URA3 gene from S. cerevisiae. The GenBank Accession Nos for the cDNA and genomic DNA sequences of RtURA3 are EU693528 and EU693529, respectively. Copyright © 2008 John Wiley & Sons, Ltd.
Photosynthetic response of Fragaria orientalis in different water contrast clonal integration
Authors: Zhang Yunchun , Zhang Qiaoying , Luo Peng , Wu Ning 
Published: August 2008

AbstractThe capacity to exchange resources and non‐resource agents is one of the most outstanding features of clonal plants. Contrast between patches in a heterogeneous environment is the main external driving force behind integration effects. It was hypothesized, on the basis of the source–sink hypothesis, that assimilate demand from drought‐stressed ramets will result in enhancement of the photosynthesis of well‐watered ramets by a mechanism of feedback regulation, that the negative effect of drought on the photosynthesis of drought‐stressed ramets will be ameliorated by physiological integration, and that these effects will be enhanced by increasing contrast. A pot experiment was conducted with clonal fragments consisting of two interconnected ramets of Fragaria orientalis. In the experiment, both the connected and the disconnected clonal fragments were divided into three water contrast groups: (1) homogeneous (no contrast) group; (2) low‐contrast group; (3) high‐contrast group. The photosynthesis and stress tolerance of drought‐stressed ramets did not decrease under the support of well‐watered ramets when they were connected, allowing clones to maintain their performance in less favorable environments. But the photosynthesis and stress tolerance of drought‐stressed ramets decreased with increasing drought‐stress when stolons were disconnected. With a feedback regulation process, the photosynthesis of well‐watered ramets connected to drought‐stressed ramets was enhanced by the latter, which can compensate, at least partially, for the cost of maintaining the stressed ramets. Drought‐stressed ramets gained more benefits in a high‐contrast environment than in a lower‐contrast environment; this can enhance the survival of drought‐stressed ramets in unfavorable habitats, especially stressed patches that would otherwise be unexploitable by independent ramets. But photosynthesis of well‐watered ramets did not increase with increasing water availability contrast. It can be concluded that photosynthesis and stress tolerance of F. orientalis was affected by clonal integration and by contrasts of water availability.
Biological Functions and Metabolism of Oleoylethanolamide
Authors: Thabuis Clémentine , Tissot‐Favre Delphine , Bezelgues Jean‐Baptiste , Martin Jean‐Charles , Cruz‐Hernandez Cristina , Dionisi Fabiola , Destaillats Frédéric 
Published: August 2008

AbstractThe present review is focused on the metabolism and the emerging roles of oleoylethanolamide (OEA) with emphasis on its effects on food intake control and lipid metabolism. The biological mechanism of action, including a non‐genomic effect mediated through peroxisome proliferator‐activated receptor alpha (PPAR‐α) and transient receptor potential vanilloid type 1 (TRPV1) receptor, is discussed. The research related to fatty acid ethanolamides has been focused until recently on anandamide and its interaction with cannabinoid receptor subtype 1. The roles of other N‐acyl ethanolamine fatty acid derivatives have been neglected until it was demonstrated that OEA can modulate food intake control through interaction with PPAR‐α. Further investigations demonstrated that OEA modulates lipid and glucose metabolism, and recent study confirmed that OEA is an antagonist of TRVP1. It has been demonstrated that OEA has beneficial effects on health by inducing food intake control, lipid β‐oxidation, body weight loss and analgesic effects. The investigation of the mechanism of action revealed that OEA activates PPAR‐α and stimulates the vagal nerve through the capsaicin receptor TRPV1. Pre‐clinical studies showed that OEA remains active when administered orally.
Establishment and functional characterization of a tracheal epithelial cell line RTEC11 from transgenic rats harboring temperature‐sensitive simian virus 40 large T‐antigen
Authors: Tabuchi Yoshiaki , Doi Takeshi , Takasaki Ichiro , Takahashi Ri‐ichi , Ueda Masatsugu , Suzuki Yoshihisa , Obinata Masuo 
Published: August 2008

AbstractA tracheal epithelial cell line RTEC11 was established from transgenic rats harboring temperature‐sensitive simian virus 40 large T‐antigen. The cells grew continuously at a permissive temperature of 33 °C but not at a non‐permissive temperature of 39 °C. Morphological and functional investigations demonstrated that the cells were polarized epithelial cells maintaining a regulated permeability barrier function. Interestingly, the expression levels of Muc1 (mucin 1) and Scgb1a1 (uteroglobin), non‐ciliated secretory cell markers, and Tubb4 (tubulin beta 4), a ciliated cell marker, were significantly increased under the cell growth‐restricted condition. Global gene expression and computational network analyses demonstrated a significant genetic network associated with cellular development and differentiation in cells cultured at the non‐permissive temperature. The tracheal epithelial cell line RTEC11 with unique characteristics should be useful as an in vitro model for studies of the physiological functions and gene expression of tracheal epithelial cells.
Contact effects of translation: Distinguishing two kinds of influence in Old English
Authors: Taylor Ann 
Published: August 2008

ABSTRACTMany of our surviving Old English (OE) texts are translations from Latin originals. Given that the syntax of Latin and OE differ in a number of ways, the possibility of transference in the process of translation is an important issue for studies of OE syntax. This article examines one syntactic structure where the syntax of the languages differ: the prepositional phrase (PP) with pronominal complement. In Latin, PPs with pronominal complements are essentially head-initial, while in OE they vary between head-initial and head-final. I show that two distinct translation effects can be distinguished, one direct and one indirect, and that these effects apply differentially to two different types of translation, biblical and nonbiblical. I relate these different translation effects to the different strategies of OE translators when faced with biblical and nonbiblical texts.
Morphosyntactic and phonological constraints on negative particle variation in French-language chat discourse
Authors: van Compernolle Rémi A. 
Published: August 2008

ABSTRACTThis study investigates the variable presence or absence of the negative morphemenein online French-language chat environments. The data indicate an overwhelming preference for the omission ofnein most instances of verbal negation, which corroborates previous studies ofnein everyday conversational French. VARBRUL analyses revealed four principal results: (i) subject type (i.e., noun phrase [NP], pronoun, or inferred subject) is the most influential factor; (ii) NPs favornepresence irrespective of the conditioning factors considered in this study; (iii) the variable presence ofneis conditioned by phonological factors within the subject pronoun category; (iv) the type of second-negative present (i.e.,pasvs. second-negative other thanpas) influencesneretention in inferred subject environments.
Line-of-Sight Networks
Authors: FRIEZE ALAN , KLEINBERG JON , RAVI R. , DEBANY WARREN 
Published: August 2008

Random geometric graphs have been one of the fundamental models for reasoning about wireless networks: one places n points at random in a region of the plane (typically a square or circle), and then connects pairs of points by an edge if they are within a fixed distance of one another. In addition to giving rise to a range of basic theoretical questions, this class of random graphs has been a central analytical tool in the wireless networking community.For many of the primary applications of wireless networks, however, the underlying environment has a large number of obstacles, and communication can only take place among nodes when they are close in space and when they have line-of-sight access to one another – consider, for example, urban settings or large indoor environments. In such domains, the standard model of random geometric graphs is not a good approximation of the true constraints, since it is not designed to capture the line-of-sight restrictions.Here we propose a random-graph model incorporating both range limitations and line-of-sight constraints, and we prove asymptotically tight results for k-connectivity. Specifically, we consider points placed randomly on a grid (or torus), such that each node can see up to a fixed distance along the row and column it belongs to. (We think of the rows and columns as ‘streets’ and ‘avenues’ among a regularly spaced array of obstructions.) Further, we show that when the probability of node placement is a constant factor larger than the threshold for connectivity, near-shortest paths between pairs of nodes can be found, with high probability, by an algorithm using only local information. In addition to analysing connectivity and k-connectivity, we also study the emergence of a giant component, as well an approximation question, in which we seek to connect a set of given nodes in such an environment by adding a small set of additional ‘relay’ nodes.