bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal polymorphism and enhanced dielectric performance of composite nanofibers of poly(vinylidene fluoride) with silver nanoparticles
Authors: Shi Naien , Duan Juanjuan , Su Jie , Huang Fengzhen , Xue Wei , Zheng Chao , Qian Yan , Chen Shufen , Xie Linghai , Huang Wei 
Published: July 2012

AbstractComposite nanofibers of poly(vinylidene fluoride) (PVF2) with silver nanoparticles are fabricated by electrospinning. According to the X‐ray diffraction patterns and Fourier transform IR (FTIR) spectra, the content of piezoelectric β‐polymorph of PVF2 is enhanced in the composite fibers of PVF2 and silver as compared with the pristine PVF2 raw materials and electrospun nanofibers. The differential scanning calorimeter (DSC) measurement indicates that the composite of PVF2 and silver has higher melting point and crystallization temperature than that of pristine PVF2 nanofibers. Moreover, the existence of silver nanoparticles greatly enhances the dielectric constant of PVF2 nanofibers and keeps a low dielectric loss simultaneously, which mainly relates to the internal fibrous structure of the composite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Study on influence of terminal structure on mechanical properties of GAP elastomers
Authors: Zhai Jinxian , Shan Zhongqing , Li Jianmin , Li Xiaodong , Guo Xiaoyan , Yang Rongjie 
Published: July 2012

AbstractTo improve mechanical properties of glycidyl azide polymer (GAP) elastomer, primary hydroxyl terminated GAP prepolymer (PH‐GAP) has been synthesized by end‐capping modification of GAP using carbamate reaction. FTIR, 13C‐NMR, GPC results indicate that the functionality, molecular weight, and molecular weight distribution of PH‐GAP are consistent with those of the original GAP. Mechanical tests indicate that mechanical properties of PH‐GAP elastomer are much better than those of GAP elastomer. Swelling tests discover that the apparent molecular weight of the network chain in PH‐GAP elastomer is much less than that of the original GAP elastomer, and PH‐GAP elastomer has much perfect network structure. Network structure defect is the main factor causing inferior mechanical properties, and the GAP prepolymer terminal structure plays an outstanding role in the mechanical properties of its cross‐linked elastomers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Polyaniline synthesis using hydrofluoric acid as doping agent: Comparative evaluation with polyaniline doped with sulfuric acid
Authors: Silveira F. Z. , Duarte G. W. , Tachinski C. G. , Piletti R. , Fiori J. , Peterson M. , Riella H. G. , Fiori M. A. 
Published: July 2012

AbstractThis work focuses on the comparison between the morphological, chemical, and electrical properties of polyaniline doped with fluoridric and polyaniline, and doped with sulfuric acid. The FT‐IR, XRD, and SEM/EDS results indicate that the use of hydrofluoric acid as doping agent does not provide meaningful changes in the crystalline and morphological structure of polyaniline. Although, the inclusion of F− type counter‐ions from the doping process with HF provide more compact, denser, and with higher electrical conductivity polymeric matrices. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Release of dexamethasone from poly(N‐vinyl pyrrolidone‐co‐n‐hexyl methacrylate) copolymers of controlled hydrophilicity
Authors: Huma Farhat , Akhter Zareen , Zafar‐Uz‐Zaman M. , Yasin Tariq 
Published: July 2012

AbstractA copolymer system with controlled hydrophilicity has been prepared through copolymerization technique and its capability as controlled drug release carrier is investigated. The effect of copolymer composition on water uptake, thermal properties, and morphology is reported. The water uptake increases with increasing N‐vinyl pyrrolidone content and diffusion of water molecules appears to be non‐Fickian. Dexamethasone has been selected as model drug and its controlled release from selected water stable copolymers follows for more than 1 month. Initial burst release of more than 50% occurs in 7 days. The remaining drug is released in a sustained way upto 37 days. Initial 10 h drug release pattern involves first‐order kinetics (NH73) and zero‐order kinetics (NH55), whereas initial 60% drug release mechanism appears to be non‐Fickian for NH73 (n = 0.71) and Case II transport (n = 1.24) for NH55. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Preparation of carboxymethyl sago pulp hydrogel from sago waste by electron beam irradiation and swelling behavior in water and various pH media
Authors: Pushpamalar Vengidesh , Langford Steven James , Ahmad Mansor , Hashim Kamaruddin , Lim Yau Yan 
Published: July 2012

AbstractSolutions of carboxymethyl sago pulp (CMSP) of various degree of substitution were irradiated with electron beam of various radiation doses. The gelation dose (Dg) and po/qo ratio (po is degradation density, qo is crosslinking density) is dependent on CMSP concentration and degree of substitution. In the range of concentrations of 10% to 80% (w/v) CMSP with degree of substitutions of 0.4, 0.6, and 0.8, the po/qo ratio decreases with increasing %CMSP showing that crosslinking processes are dominating and increasing the gel network of the CMSP hydrogel. The fourier transform infrared spectra of CMSP hydrogels of degree of substitutions of 0.4, 0.6, and 0.8 with percentage of gel fractions 25, 35, and ≥ 40 show differences in the intensity of the absorption bands at 1020–1100, 1326, and 1422 cm−1 with different degree of substitutions and percentage of gel fraction (%GF) that correspond to different extents of chain scission and crosslinking. The swelling behavior in water shows that CMSP hydrogels could absorb 3500–5300% of water by 1 g of CMSP hydrogel. The ability to absorb water increases with the decrease of degree of substitution and %GF of the CMSP hydrogels. It is also observed that the optimum pH for swelling CMSP hydrogel is at pH 7. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Poly(ethylene terephthalate)/Poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate)/Clay nanocomposites: Morphology and isothermal crystallization kinetics
Authors: Wu Jyh‐Horng , Yen Ming‐Shien , Kuo M. C. , Wu Chien‐Pang , Leu Ming‐Tsong , Li Chia‐Hao , Tsai F. K. 
Published: July 2012

AbstractThis work prepared poly(ethylene terephthalate)/clay (PET/clay), PET/poly(ethylene glycol‐co‐1,3/1,4‐cyclohexanedimethanol terephthalate) (PET/PETG), and PET/PETG/clay nanocomposites via the twin‐screw extrusion process. The organoclay in PET and PET/PETG matrices are in homogeneous dispersion, and the spacing distances between the platelets in the PET/clay and PET/PETG/clay nanocomposites are larger than 33.9 Å. Differential scanning calorimetry (DSC) and polarizing optical microscope (POM) analyses showed that the inclusion of organoclay significantly increased the crystallinities and melting temperatures of PET/clay and PET/PETG/clay nanocomposites with less time required to undergo isothermal crystallization. These findings imply the occurrence of heterogeneous nucleation. However, amorphous PETG substantially decreased the crystallinity of the crystallizable units of PET. Morphologically, the inclusion of organoclay drove the crystallites of PET from a spherulite with more perfection and less dimension to a larger spherulite. This process was extended from PET/clay to PET/PETG/clay in which the crystallites propagated in two‐dimensional and disc‐like morphology. However, blending PET with amorphous PETG imparted the larger crystallites with relatively distorted Maltese‐cross patterns. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Assessment of resin formulations and determination of the formaldehyde to urea molar ratio by near‐ and mid‐infrared spectroscopy and multivariate data analysis
Authors: Costa Nuno , Amaral Sandrina , Alvim Ricardo , Nogueira Miguel , Schwanninger Manfred , Rodrigues José 
Published: July 2012

AbstractThe molar ratios of formaldehyde (F) to urea (U) of three resin formulations in the range from 0.90 to 1.49 have been analyzed by means of Attenuated Total Reflection‐Fourier Transform Infrared (ATR‐FTIR) spectroscopy and Fourier Transform‐Near‐Infrared (FT‐NIR) spectroscopy. Application of Principal Component Analysis (PCA) to the spectra (MIR and NIR) allowed to separate them according to the molar ratio and to distinguish between two groups of resins. Soft Independent Modeling of Class Analogy (SIMCA) allowed classification of new resin samples with high model distances between the classes. Partial Least Squares Regression (PLS‐R) models based on MIR (NIR) spectra resulted in high coefficients of determination (R2) values, low errors, and high residual prediction deviations (RPD). To confirm the reproducibility of the process and to carefully evaluate twice all multivariate analysis results obtained, different batches of resins have been prepared to have an additional independent sample set. The number of samples required for MIR and possible applications of MIR and NIR spectroscopy in this context including limitations have been discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Enhancement of weld line mechanical strength using a novel ejector‐pins compression system
Authors: Nian Shih‐Chih , Huang Ming‐Shyan 
Published: July 2012

AbstractThis study proposes a novel ejector‐pins compression system (EPCS) to improve the mechanical strength of weld lines that are formed in the injection molding process. Weld lines are significant defects that affect injection molding quality, causing the poor appearance and low mechanical strength of injection‐molded parts. In this experiment, several ejector pins are placed intentionally near the weld lines appearing, and are initially sunken beneath the cavity surface to form a reflow trap such that some of the molten plastics are allowed to flow into it during the filling process. These molten plastics are then compressed by the arisen ejector pins. Accordingly, the compressed molten plastics reflow through the weld lines, disordering the molecular orientation. Experimental verification revealed that the use of an EPCS can efficiently eliminate the orientation of the molecules parallel to the weld line. The specimens' impact strength of using EPCS can increase to between one and two times than that of conventionally injection‐molded. Therefore, this simple and novel method is feasible for greatly improving the mechanical strength of weld lines. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Fabrication and characterization of mesoporous carbon nanosheets using halloysite nanotubes and polypyrrole via a template‐like method
Authors: Liu Yushan , Cai Qiang , Li Hengde , Zhang Jianmin 
Published: July 2012

AbstractA novel synthesis route for mesoporous carbon (MC) nanosheets were developed using halloysite nanotubes (HNTs), a type of natural clay that is structurally and chemically similar to mineral kaolinite, as inorganic matrix and using polypyrrole (PPy) as carbon precursor by a template‐like method. First, PPy/HNT hybrids were prepared by in situ oxidative polymerization. Carbon (C)/HNT hybrids were further obtained by pyrolysis of the PPy/HNT hybrids. MC was obtained after the removal of inorganic template by hydrochloric acid/hydrofluoric acid mixture at the end. Both the C/HNT and the MC were characterized by Fourier transform infrared spectroscopy analysis, X‐ray diffraction, Raman spectra measurement, and high‐resolution transmission electron microscopy. The MC was also characterized with specific surface area (BET). The results showed that the MC obtained was almost amorphous carbon. The increase in the ratio of [HNTs template]/[pyrrole monomer] led to an increase in the BET‐specific surface area. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Offsetting the impact of the marine ornamental trade: a case study of two temperate top shells (Osilinus lineatus and Gibbula umbilicalis) as potential clean‐up crew
Authors: Watson G. J. , Bonner A. , Murray J. M. , Hebblethwaite Z. 
Published: July 2012

Abstract

It is estimated that several million tropical gastropods are exported each year for the marine ornamental trade to become part of a clean‐up crew (those species that have a beneficial function such as controlling nuisance algae) in an aquarium. Collecting non‐tropical species could offset exploitation impacts, reduce shipping costs and increase survival rates due to shorter transport distances. However, these species must be able to survive and function at tropical marine tank temperatures (25 °C).
Two species of intertidal temperate top shell (Osilinus lineatus) and (Gibbula umbilicalis) were acclimated to 25 °C, 27 °C and 29 °C and survivorship compared with ambient (UK summer) conditions for 55 days. Virtually all G. umbilicalis died during the experiment in all elevated temperatures. In contrast, O. lineatus had minimal mortality in all treatments except the 29 °C, which reached 46.7% ±3.3 by day 55.
Locomotor activity and position in relation to the air/water interface were assessed at 25 °C and ambient conditions. All individuals from both species were active and the mean activity score did not differ between treatments. The majority (63–85%) of the individuals of both species also spent their time either submerged or at the air–water interface and those held at 25 °C spent less time on average out of the water.
Nitrocellulose plates impregnated with an algal extract were used to assess grazing of both species at 25 °C compared with ambient temperature. Over 24 h both consumed significant quantities, and no differences in levels were observed between temperatures or species.
Together this evidence shows that O. lineatus survives equally well at standard tropical aquarium temperatures and also continues to function as a clean‐up crew. Collection of this and other non‐tropical species may be an important alternative conservation approach to tropical collection if ethical and management issues are addressed. Copyright © 2012 John Wiley & Sons, Ltd.
The Gross Anatomy of the Original and Regenerated Tail in the Green Anole (Anolis carolinensis)
Authors: Ritzman Terrence B. , Stroik Laura K. , Julik Emily , Hutchins Elizabeth D. , Lasku Eris , Denardo Dale F. , Wilson‐Rawls Jeanne , Rawls J. Alan , Kusumi Kenro , Fisher Rebecca E. 
Published: July 2012

AbstractThis study investigates the gross anatomy of the original and the regenerated tail in the green anole (Anolis carolinensis). Dissections were conducted on 24 original and 13 regenerated tails. While the extrinsic muscles of the original tail in A. carolinensis are similar to those in other known Anolis lizard species, the extent of the origins of m. caudofemoralis longus and m. caudofemoralis brevis is more restricted. These differences may underlie variation in locomotor performance among anole ecomorphs. The intrinsic muscles of the original tail are also described, confirming previous findings and documenting new details, including muscle origins and insertions and the range of intraspecific variation. A comparison of the intrinsic muscles of the original tail and the regenerated tail muscles reveals key differences, such as the lack of interdigitating muscle segments and intramuscular septa in the regenerated tail. These findings, along with the replacement of interlocking vertebrae with a stiff, cartilaginous rod, suggest that important functional differences exist between the original and regenerated tail. In particular, the regenerated tail is predicted to be less capable of coordinated, fine movements. Studies of the physical properties and range of motion of the original and regenerated tail are required to test this hypothesis. This atlas of tail anatomy in A. carolinensis represents a key resource for developmental and genetic studies of tail regeneration in lizards, as well as studies of anole evolution and biomechanics. Anat Rec,, 2012. © 2012 Wiley Periodicals, Inc.
Computer‐based learning: Interleaving whole and sectional representation of neuroanatomy
Authors: Pani John R. , Chariker Julia H. , Naaz Farah 
Published: July 2012

AbstractThe large volume of material to be learned in biomedical disciplines requires optimizing the efficiency of instruction. In prior work with computer‐based instruction of neuroanatomy, it was relatively efficient for learners to master whole anatomy and then transfer to learning sectional anatomy. It may, however, be more efficient to continuously integrate learning of whole and sectional anatomy. A study of computer‐based learning of neuroanatomy was conducted to compare a basic transfer paradigm for learning whole and sectional neuroanatomy with a method in which the two forms of representation were interleaved (alternated). For all experimental groups, interactive computer programs supported an approach to instruction called adaptive exploration. Each learning trial consisted of time‐limited exploration of neuroanatomy, self‐timed testing, and graphical feedback. The primary result of this study was that interleaved learning of whole and sectional neuroanatomy was more efficient than the basic transfer method, without cost to long‐term retention or generalization of knowledge to recognizing new images (Visible Human and MRI). Anat Sci Educ. © 2012 American Association of Anatomists.
Diastereoselective Total Synthesis of (±)‐Schindilactone A, Part 2: Construction of the Fully Functionalized CDEFGH Ring System
Authors: Li Yong , Chen Zhi‐Xing , Xiao Qing , Ye Qin‐Da , Sun Tian‐Wen , Meng Fan‐Ke , Ren Wei‐Wu , You Lin , Xu Ling‐Min , Wang Yue‐Fan , Chen Jia‐Hua , Yang Zhen 
Published: July 2012

AbstractThe successful synthesis of the highly complex model compound (2) of the CEFGH ring system of schindilactone A (1) is described. Several synthetic methodologies were developed and applied to achieve this goal, including ring‐closing metathesis (RCM) and Co–thiourea‐catalyzed Pauson–Khand reactions. Furthermore, two independent approaches were developed for the construction of the GH ring of model compound 2, the key steps of which included Pd–thiourea‐catalyzed carbonylative annulation, methylation, and sequential RCM/oxa‐Michael‐addition reactions. The chemistry developed herein has provided a greater understanding of the synthesis of schindilactone A (1) and its analogous compounds of the same family.
Diastereoselective Total Synthesis of (±)‐Schindilactone A, Part 3: The Final Phase and Completion
Authors: Ren Wei‐Wu , Chen Zhi‐Xing , Xiao Qing , Li Yong , Sun Tian‐Wen , Zhang Zi‐Yang , Ye Qin‐Da , Meng Fan‐Ke , You Lin , Zhao Ming‐Zhe , Xu Ling‐Min , Tang Ye‐Feng , Chen Jia‐Hua , Yang Zhen 
Published: July 2012

AbstractThe final phase for the total synthesis of (±)‐schindilactone A (1) is described herein. Two independent synthetic approaches were developed that featured Pd–thiourea‐catalyzed cascade carbonylative annulation reactions to construct intermediate 3 and a RCM reaction to make intermediate 4. Other important steps that enabled the completion of the synthesis included: 1) A Ag‐mediated ring‐expansion reaction to form vinyl bromide 17 from dibromocyclopropane 30; 2) a Pd‐catalyzed coupling reaction of vinyl bromide 17 with a copper enolate to synthesize ketoester 16; 3) a RCM reaction to generate oxabicyclononenol 10 from diene 11; 4) a cyclopentenone fragment in substrate 8 was constructed through a Co–thiourea‐catalyzed Pauson–Khand reaction (PKR); 5) a Dieckmann‐type condensation to successfully form the A ring of schindilactone A (1). The chemistry developed for the total synthesis of schindilactone A (1) will shed light on the synthesis of other family members of schindilactone A.
Evidence of Two Key Intermediates Contributing to the Selectivity of P450‐Biomimetic Oxidation of Sulfides to Sulfoxides and Sulfones
Authors: Zhou Xinrui , Chen Xian , Jin Yaqin , Markó Istvan E. 
Published: July 2012

AbstractA mild process for the selective oxidation of sulfides is in great demand. Therefore, probing the mechanism underlying the biological oxidation of sulfides under ambient conditions may provide valuable insights for the development of such a reaction. Based on porphyrin models of P450 enzymes, evidence of two key intermediates, Int0 and Int1, in this reaction is provided. Spectroscopic studies indicated the formation of a hydroperoxide‐iron(III) species (Int0) upon addition of H2O2. This intermediate proved to be highly selective for sulfoxide production. By contrast, a defined porphyrin oxoiron(IV) cation radical (Int1) directly reacted with sulfoxides, leading selectively to the corresponding sulfones. Interestingly, the available sulfoxides reversibly act as a new axial ligand for Int0 forming a more active species Int0SO. The amount of Int0 increased in the presence of alkyl, aryl, or aromatic sulfides, while Int1 formed in the absence of these sulfides. Thus, sulfoxides and sulfones would selectively form under conditions that favor the corresponding intermediates, which elucidate the biological oxidation pathway.
Quantitative analyses of individual sugars in mixture using FRET‐based biosensors
Authors: Ha Jae‐Seok , Gam Jongsik , Choi Su‐Lim , Oh Ki‐Hoon , Ro Hyeon‐Su , Song Jae Jun , Shin Chul Soo , Lee Seung‐Goo 
Published: July 2012

AbstractMolecular biosensors were developed and applied to measure individual sugars in biological mixtures such as bacterial culture broths. As the sensing units, four sugar‐binding proteins (SBPs for allose, arabinose, ribose, and glucose) were selected from the Escherichia coli genome and connected to a cyan fluorescent protein and yellow fluorescent protein via dipeptide linkers (CFP‐L‐SBP‐YFP). The putative sensors were randomized in the linker region (L) and then investigated with regard to the intensity of fluorescence resonance energy transfer on the binding of the respective sugars. As a result, four representatives were selected from each library and examined for their specificity using 16 available sugars. The apparent dissociation constants of the allose, arabinose, ribose, and glucose sensors were estimated to be 0.35, 0.36, 0.17, and 0.18 μM. Finally, the sugar sensors were applied to monitor the consumption rate of individual sugars in an E. coli culture broth. The individual sugar profiles exhibited a good correlation with those obtained using an HPLC method, confirming that the biosensors offer a rapid and easy‐to‐use method for monitoring individual sugars in mixed compositions. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Laccase for biobleaching of eucalypt kraft pulp by means of a modified industrial bleaching sequence
Authors: Moldes D. , Vidal T. 
Published: July 2012

AbstractBiobleaching of kraft pulp is a possible application of laccase, but it has not been described in detail for complete industrial bleaching sequences yet. Therefore, in this work, the biobleaching of Eucalyptus globulus kraft pulp was performed using a modified industrial totally chlorine‐free sequence. The modification consisted in the substitution of an enzymatic delignification stage, based on the application of laccase from Trametes villosa, for the first alkaline extraction one. The enzymatic stage was performed with several synthetic and natural mediators, namely 1‐hydroxybenzotriazole (HBT), violuric acid (VA), methyl syringate, and syringaldehyde. Several pulp properties were analyzed after each stage of the bleaching process—kappa number, ISO brightness, viscosity, and optical properties of CIEL*a*b* system. The new biobleaching sequence improved the pulp properties, in comparison to the conventional bleaching sequence, if HBT or VA was used as mediators. VA was selected as the best mediator of those tested and the effect of its concentration in the enzymatic stage was subsequently studied. Reducing the initial concentration by 30%, the same pulp quality was obtained, but if the reduction attained 60%, an important decrease in pulp integrity was detected. The modified bleaching sequence could improve the bleached pulp properties (kappa number 10%, ISO brightness 1%, and viscosity 5%) in comparison to the mill sequence. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012