bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melt spinning of conducting polymeric composites containing carbonaceous fillers
Authors: Strååt Martin , Toll Staffan , Boldizar Antal , Rigdahl Mikael , Hagström Bengt 
Published: September 2010

AbstractFibers produced by melt spinning of conductive polymer composites are attractive for several applications; the main drawback is however reduced processability at high filler concentrations. Carbon nanotubes (CNTs) are considered suitable fillers for conductive polymer composites, replacing conductive grades of carbon black (CB). In this study, the fiber‐forming properties of conductive polymer composites based on a conductive grade of CB and two masterbatches with CNT in a polyethylene matrix were investigated. The CB was also used in a polypropylene matrix for comparison. The rheological properties of the filler‐containing melts in shear and their extensional behavior were evaluated. A piston‐driven device was used to extrude the molten materials through a capillary; different capillary geometries were tested. Fibers were produced at various draw ratios, and their conductivity was determined. To assess the ultimate extensibility, a modified Rheotens method was used. The results showed that a conductive CB grade can have a lower percolation threshold and higher conductivity than a material with CNT. Conductivity decreased with increasing melt draw ratio for both types of fillers. The spinnability of the materials decreased with increasing concentration of filler material and correlations were found between spinnability and melt elasticity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of tetraacid on the properties of ODPA/4,4′‒ODA polyimide foams
Authors: Liu Xiao‒Yan , Zhan Mao‒Sheng , Shen Yan‒Xia , Wang Kai 
Published: September 2010

AbstractIn this research, a new flexible polyimide (PI) foams was successfully prepared and characterized based on precursor powder foaming. This foams were derived from 3,3',4,4'‒oxydiphethalic anhydride (ODPA), 3,3',4,4'‒oxydiphethalic tetraacid (ODPA‒tetraacid), and 4,4'‒oxydianiline (4,4'‒ODA). With varying molar percentage of ODPA‒tetraacid in (ODPA + ODPA‒tetraacid), the changes of properties of PI precursor powders and PI foams were comparatively investigated. The foaming processes of PI foams were observed by a self‒made visualization device. The decomposition products of precursor powders were analyzed by thermogravimetry‒Fourier transform infrared spectroscopy (TG‒FTIR). The crystallinity of precursor powders was investigated by wide‒angle X‒ray diffraction (WXRD). The chemical structure of PI precursor powders and foams was analyzed by FTIR. The thermal properties of PI foams were tested by the methods of dynamic mechanical analysis (DMA), and TG/differential thermogravimetry (DTG) analysis. The cell structure of PI foams was observed by a scanning electron microscopy. The rebound resilience of PI foams was studied by a self‒made drop‒ball instrument. With the increasing of ODPA‒tetraacid, the inflation onset temperatures and inflation degrees of PI foams decreased from 210°C to 118°C and increased from 10 to 14.8 times, respectively. The crystallinity of PI precursor powders increased. The thermal stability of PI foams decreased. The cell structure of PI foams became more uniform and the rebound rates increased linearly. Besides, ODPA‒tetraacid did not yield any negative effect on the complete imidization of the PI precursor powder by the FTIR spectra. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanism analysis of poly(lactic acid) particles formation by mesoscale simulation
Authors: Zhu Aimei , Weng Jian , Liu Qinglin 
Published: September 2010

AbstractIn this work, the mechanism analysis of Poly(DL‐lactic acid) (PLA) particles formation is investigated by dissipative particle dynamics (DPD) simulations. The polymer PLA is usually as a carrier at the drug deliver system (DDS), first, the mechanism analysis of PLA particles formation was preceded on the basis of the blank PLA particles. At the same time, the formation of PLA particles for drug delivery systems has been investigated. The results of DPD simulations indicate that the formation of PLA particles with drug or not, consists of three steps: (1) aggregation‐individual PLA chains got aggregated with each other in solution; (2) formation and disruption of PLA particles; (3) solidification of PLA particles. At the same time, the effects of PLA, drug content on the aggregation morphology are investigated, which indicates the PLA particles with drug or not aggregated and formed is spherical particles, drug molecules are amorphously and homogeneously distributed inside the PLA matrix, the size of PLA particles increases with increasing the initial PLA content and drug content in the solution. The content of DMF is gotten when PLA chains and drug molecules begin to aggregate and form the particles. These could be used to guide the experimental preparation of PLA blank particles and DDS with desired properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A new context‐dependent term weight computed by boost and discount using relevance information
Authors: Dang E.K.F. , Luk R.W.P. , Allan J. , Ho K.S. , Chan S.C.F. , Chung K.F.L. , Lee D.L. 
Published: September 2010

AbstractWe studied the effectiveness of a new class of context‐dependent term weights for information retrieval. Unlike the traditional term frequency–inverse document frequency (TF–IDF), the new weighting of a term t in a document d depends not only on the occurrence statistics of t alone but also on the terms found within a text window (or “document‐context”) centered on t. We introduce a Boost and Discount (B&D) procedure which utilizes partial relevance information to compute the context‐dependent term weights of query terms according to a logistic regression model. We investigate the effectiveness of the new term weights compared with the context‐independent BM25 weights in the setting of relevance feedback. We performed experiments with title queries of the TREC‐6, ‐7, ‐8, and 2005 collections, comparing the residual Mean Average Precision (MAP) measures obtained using B&D term weights and those obtained by a baseline using BM25 weights. Given either 10 or 20 relevance judgments of the top retrieved documents, using the new term weights yields improvement over the baseline for all collections tested. The MAP obtained with the new weights has relative improvement over the baseline by 3.3 to 15.2%, with statistical significance at the 95% confidence level across all four collections.
A new short proof of Naranan's theorem, explaining Lotka's law and Zipf's law
Authors: Egghe Leo 
Published: September 2010

AbstractNaranan's important theorem, published in Nature in 1970, states that if the number of journals grows exponentially and if the number of articles in each journal grows exponentially (at the same rate for each journal), then the system satisfies Lotka's law and a formula for the Lotka's exponent is given in function of the growth rates of the journals and the articles. This brief communication re‐proves this result by showing that the system satisfies Zipf's law, which is equivalent with Lotka's law. The proof is short and algebraic and does not use infinitesimal arguments.
Member activities and quality of tags in a collection of historical photographs in Flickr
Authors: Stvilia Besiki , Jörgensen Corinne 
Published: September 2010

AbstractTo enable and guide effective metadata creation it is essential to understand the structure and patterns of the activities of the community around the photographs, resources used, and scale and quality of the socially created metadata relative to the metadata and knowledge already encoded in existing knowledge organization systems. This article presents an analysis of Flickr member discussions around the photographs of the Library of Congress photostream in Flickr. The article also reports on an analysis of the intrinsic and relational quality of the photostream tags relative to two knowledge organization systems: the Thesaurus for Graphic Materials (TGM) and the Library of Congress Subject Headings (LCSH). Thirty seven percent of the original tag set and 15.3% of the preprocessed set (after the removal of tags with fewer than three characters and URLs) were invalid or misspelled terms. Nouns, named entity terms, and complex terms constituted approximately 77% of the preprocessed set. More than a half of the photostream tags were not found in the TGM and LCSH, and more than a quarter of those terms were regular nouns and noun phrases. This suggests that these terms could be complimentary to more traditional methods of indexing using controlled vocabularies.
The effect of spelling and retrieval system familiarity on search behavior in online public access catalogs: A mixed methods study
Authors: Willson Rebekah , Given Lisa M. 
Published: September 2010

AbstractAlthough technology can often correct spelling errors, the complex tasks of information searching and retrieval in an online public access catalog (OPAC) are made more difficult by these errors in users' input and bibliographic records. This study examines the search behaviors of 38 university students, divided into groups with either easy‐to‐spell or difficult‐to‐spell search terms, who were asked to find items in the OPAC with these search terms. Search behaviors and strategy use in the OPAC and on the World Wide Web (WWW) were examined. In general, students used familiar Web resources to check their spelling or discover more about the assigned topic. Students with difficult‐to‐spell search terms checked spelling more often, changed search strategies to look for the general topic and had fewer successful searches. Students unable to find the correct spelling of a search term were unable to complete their search. Students tended to search the OPAC as they would search a search engine, with few search terms or complex search strategies. The results of this study have implications for spell checking, user‐focused OPAC design, and cataloging. Students' search behaviors are discussed by expanding Thatcher's (2006) Information‐Seeking Process and Tactics for the WWW model to include OPACs.
Principal pathogenetic components and biological endophenotypes in autism spectrum disorders
Authors: Sacco Roberto , Curatolo Paolo , Manzi Barbara , Militerni Roberto , Bravaccio Carmela , Frolli Alessandro , Lenti Carlo , Saccani Monica , Elia Maurizio , Reichelt Karl‐Ludvig , Pascucci Tiziana , Puglisi‐Allegra Stefano , Persico Antonio M. 
Published: September 2010

AbstractAutism is a complex neurodevelopmental disorder, likely encompassing multiple pathogenetic components. The aim of this study is to begin identifying at least some of these components and to assess their association with biological endophenotypes. To address this issue, we recruited 245 Italian patients with idiopathic autism spectrum disorders and their first‐degree relatives. Using a stepwise approach, patient and family history variables were analyzed using principal component analysis (“exploratory phase”), followed by intra‐ and inter‐component cross‐correlation analyses (“follow‐up phase”), and by testing for association between each component and biological endophenotypes, namely head circumference, serotonin blood levels, and global urinary peptide excretion rates (“biological correlation phase”). Four independent components were identified, namely “circadian & sensory dysfunction,” “immune dysfunction,” “neurodevelopmental delay,” and “stereotypic behavior,” together representing 74.5% of phenotypic variance in our sample. Marker variables in the latter three components are positively associated with macrocephaly, global peptiduria, and serotonin blood levels, respectively. These four components point toward at least four processes associated with autism, namely (I) a disruption of the circadian cycle associated with behavioral and sensory abnormalities, (II) dysreactive immune processes, surprisingly linked both to prenatal obstetric complications and to excessive postnatal body growth rates, (III) a generalized developmental delay, and (IV) an abnormal neural circuitry underlying stereotypies and early social behaviors.
Teaching children with autism a basic component skill of perspective‐taking
Authors: Gould Evelyn , Tarbox Jonathan , O'Hora Denis , Noone Steve , Bergstrom Ryan 
Published: September 2010

AbstractPerspective‐taking is an area of human functioning that is rarely studied by behavior analysts but likely entails a complex repertoire of verbal and relational behavior. Perspective‐taking is generally acknowledged to be an important skill for successful social functioning and a significant amount of research has documented deficits in these skills in individuals with autism. However, little previous research has examined behavioral intervention procedures for remediating these deficits. The current study evaluated the effectiveness of a multiple exemplar training procedure for teaching three children with autism to identify what other people can see, a simple component skill of perspective‐taking. All participants demonstrated generalization to novel table‐top tasks but generalization to natural environment probes was less consistent. Results are discussed in terms of the behavioral history required to develop perspective‐taking repertoires, as well as for the development of effective interventions. Descriptors: Perspective‐taking, autism, Theory of Mind, conditional discrimination, and multiple exemplar training. Copyright © 2010 John Wiley & Sons, Ltd.
Studies on the mass and temperature dependence of lyoluminescence intensity of microcrystalline powder of KCl
Authors: Nayar V. , Chowdhary P. S. , Bhujbal P. M. , Dhoble S. J. 
Published: September 2010

ABSTRACTThe temperature and mass dependence of lyoluminescence intensity of γ‐irradiated colored potassium chloride powder have been studied using a photomultiplier tube connected to an x–y recorder. The peak lyoluminescence intensity increases with increasing amount of solute added up to 50 mg and then tends to saturate. The lyoluminescence (LL) glow curves with mass of KCl microcrystals show that initially the LL intensity increases with time and then decreases exponentially with time. The decay time consists of two components for all the masses. The dependence of decay time, especially the longer component on mass, has been investigated. The temperature dependence of LL intensity shows that initially the peak LL intensity increases with temperature up to 60°C, and then decreases with further increase in temperature. The decay time tends to decrease with increasing temperature. An explanation for the experimental results has been attempted. Copyright © 2010 John Wiley & Sons, Ltd.
Aqueous synthesis of CdTe/CdS/ZnS quantum dots and their optical and chemical properties
Authors: Li Zhong , Dong Chaoqing , Tang Lichuan , Zhu Xin , Chen Hongjin , Ren Jicun 
Published: September 2010

ABSTRACTIn this paper, we described a strategy for synthesis of thiol‐coated CdTe/CdS/ZnS (core–shell–shell) quantum dots (QDs) via aqueous synthesis approach. The synthesis conditions were systematically optimized, which included the size of CdTe core, the refluxing time and the number of monolayers and the ligands, and then the chemical and optical properties of the as‐prepared products were investigated. We found that the mercaptopropionic acid (MPA)‐coated CdTe/CdS/ZnS QDs presented highly photoluminescent quantum yields (PL QYs), good photostability and chemical stability, good salt tolerance and pH tolerance and favorable biocompatibility. The characterization of high‐resolution transmission electron microscopy (HRTEM), X‐ray powder diffraction (XRD) and fluorescence correlation spectroscopy (FCS) showed that the CdTe/CdS/ZnS QDs had good monodispersity and crystal structure. The fluorescence life time spectra demonstrated that CdTe/CdS/ZnS QDs had a longer lifetime in contrast to fluorescent dyes and CdTe QDs. Furthermore, the MPA‐stabilized CdTe/CdS/ZnS QDs were applied for the imaging of cells. Compared with current synthesis methods, our synthesis approach was reproducible and simple, and the reaction conditions were mild. More importantly, our method was cost‐effective, and was very suitable for large‐scale synthesis of CdTe/CdS/ZnS QDs for future applications. Copyright © 2010 John Wiley & Sons, Ltd.
A sensitive fluorescence reagent, 2‐[2‐(7H‐dibenzo[a,g]carbazol‐7‐yl)‐ethoxy]ethyl chloroformate, for amino acids determination in Saussurea involucrate and Artemisia capillaris Thunb using high‐performance liquid chromatography with fluorescence detection and identification with mass spectroscopy/electrospray ionization source
Authors: Li Guoliang , Sun Zhiwei , Song Cuihua , Xia Lian , Zheng Jie , Suo Yourui , You Jinmao 
Published: September 2010

AbstractRecent researches shows that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. More precise analysis of AA composition is reckoned to be one of the most important applications in the biomedical and pharmaceutical fields. In this paper, we develop a sample, sensitive and mild method using 2‐[2‐(7H‐dibenzo[a,g]carbazol‐7‐yl)‐ethoxy]ethyl chloroformate (DBCEC) as A labeling reagent for AA determination by high‐performance liquid chromatography (HPLC) with fluorescence detection (FLD) and identification with mass spectroscopy. The maximum excitation and emission wavelengths for DBCEC‐AA derivatives were 300 and 395 nm, respectively. This method, in conjunction with a gradient elution, offered a baseline resolution of 20 AA on a reversed‐phase Hypersil BDS C18 column. LC separation for the derivatized AA showed good reproducibility, and all AA were found to give excellent linear responses with correlation coefficients > 0.9993. The calculated detection limits with a 25.0 fmol injection of each AA (at a signal‐to‐noise ratio of 3:1) ranged from 2.62 to 22.6 fmol. This method was applied to determine the AA composition in Saussurea involucrate and Artemisia capillaris Thunb. Meanwhile, this method exhibits a powerful potential for trace analysis of AA from biomedicine, foodstuff and other complex samples. Copyright © 2010 John Wiley & Sons, Ltd.
A reliable method of liquid chromatography for the quantification of acetaminophen and identification of its toxic metabolite N‐acetyl‐p‐benzoquinoneimine for application in pediatric studies
Authors: Flores‐Pérez Carmen , Chávez‐Pacheco Juan Luis , Ramírez‐Mendiola Blanca , Alemón‐Medina Radamés , García‐Álvarez Raquel , Juárez‐Olguín Hugo , Flores‐Pérez Janett 
Published: September 2010

AbstractThe aim of the present study was to develop a simple, selective and reliable method to quantify acetaminophen and its toxic metabolite N‐acetyl‐p‐benzoquinoneimine (NAPQI) for pediatric studies using 100 µL plasma samples, by reverse‐phase HPLC and UV detection. The assay was performed using a C18 column and an isocratic elution with water–methanol–formic acid (70:30:0.15; v/v/v) as mobile phase. Linearity of the method was assayed in the range of 1–30 µg/mL for acetaminophen and 10–200 µg/mL for NAPQI, with a correlation coefficient r = 0.999 for both compounds, and inter‐ and intra‐day coefficients of variation of less than 13%. Several commonly co‐administered drugs were analyzed for selectivity and no interference with the determinations was observed. The detection and quantification limits for acetaminophen and NAPQI were 0.1 and 1 µg/mL, and 0.1 and 10 µg/mL respectively. The present method can be used to monitor acetaminophen levels using 100 µL plasma samples, which may be helpful when very small samples need to be analyzed, as in pharmacokinetics determination or drug monitoring in plasma in children. This assay is also able to detect the NAPQI for drug monitoring in patients diagnosed with acetaminophen intoxication. Copyright © 2010 John Wiley & Sons, Ltd.
Quantitative analysis of nine coumarins in rat urine and bile after oral administration of Radix Glehniae extract by high‐performance liquid chromatography–electrospray ionization tandem mass spectrometry
Authors: Liu Man , Shi Xiaowei , Yang Wei , Liu Songchen , Wang Na , Shi Rui , Qiao Shi , Wang Qiao , Wang Yongli 
Published: September 2010

AbstractCoumarins are the primary bioactive ingredients in Radix Glehniae, named Beishashen in China, which possesses many pharmacological activities, including anticancer, anti‐inflammation and antivirus activities. In the present study, we employed a sensitive and selective high‐performance liquid chromatography–electrospray ionization–tandem mass spectrometry (HPLC‐ESI‐MS/MS) method for the quantification of nine coumarins in rat urine and bile: scopoletin (1), xanthotoxol (2), xanthotoxin (3), psoralen (4), isoimpinellin (5), bergapten (6), oxypeucedanin (7), imperatorin (8) and isoimperatorin (9). Pimpinellin (10) was used as the internal standard (IS). The urine and bile samples were pretreated by liquid–liquid extraction with ethyl acetate (EtOAc). The chromatographic separation was carried out on a C18 column with gradient elution. The detection of analytes was performed on a tandem mass system equipped with a turbo ion spray interface in positive mode using multiple‐reaction monitoring (MRM). The specificity, linearity, accuracy, precision, recovery, matrix effect and several stabilities were validated for coumarins in rat urine and bile samples. The results showed that this method is robust, specific and sensitive and it can successfully fulfill the requirements of the excretion study of the nine coumarins in Radix Glehniae. Copyright © 2010 John Wiley & Sons, Ltd.
Highly sensitive method for the determination of a novel triple kinase inhibitor with anti‐cancer activity, JI‐101, in rat plasma by liquid chromatography–electrospray ionization tandem mass spectrometry: application to a pharmacokinetic study
Authors: Gurav Sandip Dhondiram , Gilibili Ravindranath Reddy , Jeniffer Sherine , Giri Sanjeev , Srinivas Nuggehally R , Mullangi Ramesh 
Published: September 2010

AbstractA highly sensitive, rapid assay method has been developed and validated for the estimation of JI‐101 in rat plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The assay procedure involves extraction of JI‐101 and phenacetin (internal standard, IS) from rat plasma with a solid‐phase extraction process. Chromatographic separation was achieved using a binary gradient using mobile phase A (acetonitrile) and B (0.2% formic acid in water) at a flow rate of 0.30 mL/min on a Prodigy ODS column with a total run time of 4.0 min. The MS/MS ion transitions monitored were 466.1 → 265 for JI‐101 and 180.1 → 110.1 for IS. Method validation and sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 5.03 ng/mL and the linearity range extended from 5.03 to 2014 ng/mL. The intra‐day and inter‐day precisions were in the ranges of 1.17–19.6 and 3.09–10.4%, respectively. This method has been applied to a pharmacokinetic study of JI‐101 in rats. Copyright © 2010 John Wiley & Sons, Ltd.