bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of microstructural functional polyaniline layers on SPEEK/HPW proton exchange membranes
Authors: Ren Suzhen , Xu Meiling , Yang Ying , Ma Shaobo , Hao Ce 
Published: June 2014

ABSTRACTIn this study, a method is developed to fabricate sulfonated poly (ether ether ketone)/phosphotungstic acid‐polyaniline (SPEEK/HPW‐PANI) membranes by in situ polymerization of aniline for the purpose of decreasing the weight loss of HPW in the membranes. The synthesis involves the production of a SPEEK/HPW hybrid membrane followed by different layer of PANI coatings on the membrane surface, and subsequent treatment using drying in vacuum procedures. The scanning electronic microscopy images showed that HPW had good compatibility with SPEEK polymers and energy dispersive X‐ray spectroscopy revealed the successfully doping with HPW and polymerization of PANI. The surface of SPEEK/HPW‐PANI becomes more compact than that of SPEEK/HPW and pure SPEEK, which may lead to reduce the water uptake and swelling property. The proton conductivity was found for the SPEEK/HPW‐PANI‐5 composite membrane (91.53 mS/cm at 80°C) higher than that of pure SPEEK membrane (68.72 mS/cm at 80°C). Better thermal stability was determined in both SPEEK/HPW and SPEEK/HPW‐PANI membranes than pristine SPEEK membrane. Therefore, PANI is a good potential coating for organic–inorganic hybrid e.g. SPEEK/HPW membrane materials to improve their hydrothermal stable properties and SPEEK/HPW PANI is a material that shows promise as a proton exchange membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41033.
Synthesis of chitosan‐graft‐β‐cyclodextrin for improving the loading and release of doxorubicin in the nanopaticles
Authors: Lu Lu , Shao Xiaohong , Jiao Yanpeng , Zhou Changren 
Published: June 2014

ABSTRACTChitosan‐graft‐β‐cyclodextrin (CS‐g‐β‐CD) copolymer was synthesized by conjugating β‐cyclodextrins to chitosan molecules through click chemistry. The copolymer structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). CS‐g‐β‐CD/CMC nanoparticles were prepared by a polyelectrolyte complexation process in aqueous solution between CS‐g‐β‐CD copolymer and carboxymethyl chitosan (CMC), which was used to load anticancer drug (Doxorubicin hydrochloride, DOX·HCl) with hydrophobic group. The particle size, surface charge, zeta potential, and morphology of the nanoparticles were characterized with dynamic light scattering. The drug loading efficiency and in vitro release of DOX·HCl of the nanoparticles were measured by ultraviolet spectrophotometer. The results demonstrated that the size, surface charge and drug loading efficiency of the nanoparticles could be modulated by the fabrication conditions. The drug loading efficiency of CS‐g‐β‐CD/CMC nanoparticles was improved from 52.7% to 88.1% because of the presence of β‐CD moieties with hydrophobic cavities, which can form inclusion complexes with the drug molecules. The in vitro release results showed that the CS‐g‐β‐CD/CMC nanoparticles released DOX·HCl in a controlled manner, importantly overcoming the initial burst effect. These nanoparticles possess much potential to be developed as anticancer drug delivery systems, especially those drugs with hydrophobic group. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41034.
Surface modification using self‐assembled layers of amphiphilic cyclodextrins
Authors: Lumholdt Ludmilla , Thorbjørn Terndrup Nielsen , Kim Lambertsen Larsen 
Published: June 2014

ABSTRACTIn this study six amphiphilic cyclodextrin derivatives were prepared by esterification and used to coat five industrial products made from polypropylene, polyethylene, polyvinyl chloride, or polyurethane using a new, patented coating technology. This simple approach, which consists merely of dipping the material to be coated into a suspension of a given cyclodextrin derivative in an ethanol/water solution, was used to functionalize support materials with a coat that is stable in aqueous solutions and which renders the coated materials hydrophilic. The functionalization proved to be controllable in terms of amount of cyclodextrin on the surface and can be implemented in existing production lines without investment in advanced production equipment. It is hypothesized that the cyclodextrins order themselves in structured layers forming channel‐like structures preserving the very large potential for uptake and release of active compounds that is known to cyclodextrins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41047.
Do Student Evaluations of University Reflect Inaccurate Beliefs or Actual Experience? A Relative Rank Model
Authors: Brown Gordon D. A. , Wood Alex M. , Ogden Ruth S. , Maltby John 
Published: June 2014

ABSTRACTIt was shown that student satisfaction ratings are influenced by context in ways that have important theoretical and practical implications. Using questions from the UK's National Student Survey, the study examined whether and how students' expressed satisfaction with issues such as feedback promptness and instructor enthusiasm depends on the context of comparison (such as possibly inaccurate beliefs about the feedback promptness or enthusiasm experienced at other universities) that is evoked. Experiment 1 found strong effects of experimentally provided comparison context—for example, satisfaction with a given feedback time depended on the time's relative position within a context. Experiment 2 used a novel distribution‐elicitation methodology to determine the prior beliefs of individual students about what happens in universities other than their own. It found that these beliefs vary widely and that students' satisfaction was predicted by how they believed their experience ranked within the distribution of others' experiences. A third study found that relative judgement principles also predicted students' intention to complain. An extended model was developed to show that purely rank‐based principles of judgement can account for findings previously attributed to range effects. It was concluded that satisfaction ratings and quality of provision are different quantities, particularly when the implicit context of comparison includes beliefs about provision at other universities. Quality and satisfaction should be assessed separately, with objective measures (such as actual times to feedback), rather than subjective ratings (such as satisfaction with feedback promptness), being used to measure quality wherever practicable. © 2014 The Authors. Journal of Behavioral Decision Making published by John Wiley & Sons Ltd.
Conformational preferences of peptide–peptoid hybrid oligomers
Authors: Butterfoss Glenn L. , Drew Kevin , Renfrew P. Douglas , Kirshenbaum Kent , Bonneau Richard 
Published: June 2014

ABSTRACTPeptomers are oligomeric molecules composed of both α‐amino acids and N‐substituted glycine monomers, thus creating a hybrid of peptide and peptoid units. Peptomers have been used in several applications such as antimicrobials, protease inhibitors, and antibody mimics. Despite the considerable promise of peptomers as chemically diverse molecular scaffolds, we know little about their conformational tendencies. This lack of knowledge limits the ability to implement computational approaches for peptomer design. Here we computationally evaluate the local structural propensities of the peptide–peptoid linkage. We find some general similarities between the peptide residue conformational preferences and the Ramachandran distribution of residues that precede proline in folded protein structures. However, there are notable differences. For example, several β‐turn motifs are disallowed when the i+2 residue is also a peptoid monomer. Significantly, the lowest energy geometry, when dispersion forces are accounted for, corresponds to a “cis‐Pro touch‐turn” conformation, an unusual turn motif that has been observed at protein catalytic centers and binding sites. The peptomer touch‐turn thus represents a useful design element for the construction of folded oligomers capable of molecular recognition and as modules in the assembly of structurally complex peptoid–protein hybrid macromolecules. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 369–378, 2014.
Host cell pigmentation in Scenedesmus dimorphus as a beacon for nascent parasite infection
Authors: Collins Aaron M. , Jones Howland D.T. , McBride Robert C. , Behnke Craig , Timlin Jerilyn A. 
Published: June 2014

ABSTRACTBiofuels derived from the mass cultivation of algae represent an emerging industry that aims to partially displace petroleum based fuels. Outdoor, open‐pond, and raceway production facilities are attractive options for the mass culture of algae however, this mode of cultivation leaves the algae susceptible to epidemics from a variety of environmental challenges. Infestations can result in complete collapse of the algal populations and destruction of their valuable products making it paramount to understand the host–pathogen relationships of known algal pests in order to develop mitigation strategies. In the present work, we characterize the spatial‐temporal response of photosynthetic pigments in Scenedesmus dimorphus to infection from Amoeboaphelidium protococcarum, a destructive endoparasite, with the goal of understanding the potential for early detection of infection via host pigment changes. We employed a hyperspectral confocal fluorescence microscope to quantify these changes in pigmentation with high spatial and spectral resolution during early parasite infection. Carotenoid abundance and autofluorescence increased within the first 24 h of infection while chlorophyll emission remained constant. Changes in host cell photosynthesis and bulk chlorophyll content were found to lag behind parasite replication. The results herein raise the possibility of using host–cell pigment changes as indicators of nascent parasite infection. Biotechnol. Bioeng. 2014;111: 1748–1757. © 2014 Wiley Periodicals, Inc.
Characterization and quantitative amino acids analysis of analgesic peptides in cinobufacini injection by size exclusion chromatography, matrix‐assisted laser desorption/ionization time of flight mass spectrometry and gas chromatography mass spectrometry
Authors: Wu Xu , Si Nan , Bo Gao , Hu Hao , Yang Jian , Bian Baolin , Zhao Hai Yu , Wang Hongjie 
Published: June 2014

AbstractCinobufacini injection that comes from the water extract of Bufo bufo gargarizans Cantor skin is widely used for cancer treatment in China. Peptide is one of its major types of constituents, however the biological effects and content of this injection are little reported. In present study, the analgesic effect of peptides was determined and evaluated by in‐vivo models. To characterize and quantitatively analyze these peptides, a reliable and efficient method combining size exclusion chromatography and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry with amino acid analysis was developed. The peptides presented as a series of analogs with similar molecular weights mostly ranging from 2 to 8 kDa. The amino acid analysis by gas chromatography mass spectrometry (GC‐MS) was developed to determine both free and combined amino acids (FAA and CAA) in cinobufacini injection. This method achieved good linearity (R2, 0.9909–0.9999) and low limit of detection and quantification. FAA and CAA samples were efficiently analyzed by modified Phenomenex EZ: faast procedure. For the sample analysis, the method showed good repeatability (relative standard deviation, RSD ≤ 10%). For most FAA and CAA the mean recoveries were >80% with RSD <10%. The GC‐MS based method is useful for quality assurance of both FAA and CAA in cinobufacini injection. Copyright © 2014 John Wiley & Sons, Ltd.
UPLC‐MS/MS determination of voriconazole in human plasma and its application to a pharmacokinetic study
Authors: Wang Zhe , Huang Cheng‐ke , Sun Wei , Xiao Cui , Wang Zeng‐shou 
Published: June 2014

AbstractA sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC‐MS/MS) method was developed to determine voriconazole in human plasma. Sample preparation was accomplished through a simple one‐step protein precipitation with methanol. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using an isocratic mobile phase system composed of acetonitrile and water containing 1% formic acid (45:55, v/v) at a flow rate of 0.50 mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 351.0 → 281.5 and m/z 237.1 → 194.2 were used to quantify voriconazole and carbamazepine (internal standard), respectively. The linearity of this method was found to be within the concentration range of 2.0–1000 ng/mL with a lower limit of quantification of 2.0 ng/mL. Only 1.0 min was needed for an analytical run. This fully validated method was successfully applied to the pharmacokinetic study after oral administration of 200 mg voriconazole to 20 Chinese healthy male volunteers. Copyright © 2014 John Wiley & Sons, Ltd.
Target cell extraction coupled with LC‐MS/MS analysis for screening potential bioactive components in Ginkgo biloba extract with preventive effect against diabetic nephropathy
Authors: Qiu Jing‐ying , Chen Xu , Zheng Xiao‐xiao , Jiang Xiang‐lan , Yang Dong‐zhi , Yu Yan‐yan , Du Qian , Tang Dao‐quan , Yin Xiao‐xing 
Published: June 2014

AbstractA rapid and useful approach for screening potential bioactive components in Ginkgo biloba extract (GBE) with preventive effect against diabetic nephropathy (DN) was developed using mesangial cells extraction coupled with high‐performance liquid chromatography tandem mass spectrometry (LC‐MS/MS) analysis. Mesangial cells were first divided into two groups according to their treatments with high glucose or high glucose plus GBE. After incubation for 4, 8, 12, 16, 24 and 48 h, the cells were harvested and extracted with 40% acetic acid in water before LC‐MS/MS analysis. Then, 19 compounds and five metabolites were found to selectively combine with mesangial cells. Notably, compounds including quercetin and rutin were identified or tentatively characterized according to the results of retention time and MS spectra, which is highly consistent with our previous reports that quercetin and rutin are potent protective agents against glomerulosclerosis in DN. Therefore, all these results indicate that target cell extraction coupled with LC‐MS/MS analysis can be successfully applied for predicting the bioactive components in GBE with preventive effect against DN. Copyright © 2014 John Wiley & Sons, Ltd.
Simultaneous determination of linarin, naringenin and formononetin in rat plasma by LC‐MS/MS and its application to a pharmacokinetic study after oral administration of Bushen Guchi Pill
Authors: Guo Panpan , Dong Lihua , Yan Wenying , Wei Jianceng , Wang Chunying , Zhang Zijian 
Published: June 2014

AbstractA sensitive and reproducible liquid chromatography tandem mass spectrometry (LC‐MS/MS) method was developed and validated for the simultaneous determination of linarin, naringenin and formononetin in rat plasma after addition of sulfamethoxazole as the internal standard (IS). Separation was carried out on a Diamonsil C18 column (150 × 4.6 mm, 5 µm) with liner gradient elution using methanol (A) and 0.5‰ formic acid aqueous solution (B). Detection was performed on a triple‐quadrupole linear ion trap mass spectrometer with the negative ion electrospray ionization in multiple‐reaction monitoring (MRM) mode. The MRM transitions were m/z 591.2 → 283.2, 271.0 → 150.9, 266.9 → 252.0 and 252.0 → 155.9 for linarin, naringenin, formononetin and IS, respectively. All analytes showed good linearity within the concentration range (r > 0.9973). The lower limits of quantitation of linarin, naringenin and formononetin were 0.64, 1.07 and 1.04 ng/mL, respectively. Intra‐day and inter‐day precisions of the investigated components exhibited an RSD within 9.96%, and the accuracy (relative error) ranged from −11.25 to 9.38% at all quality control levels. The developed method was successfully applied to a pharmacokinetic study of linarin, naringenin and formononetin in rats after oral administration of Bushen Guchi Pill. Copyright © 2014 John Wiley & Sons, Ltd.
Synthesis of Heterocycles through Transition‐Metal‐Catalyzed Isomerization Reactions
Authors: Ishoey Mette , Nielsen Thomas E. 
Published: June 2014

AbstractMetal‐catalyzed isomerization of N‐ and O‐allylic systems is emerging as an effective method to form synthetically useful iminium and oxocarbenium intermediates. In the presence of tethered nucleophiles, several recent examples illuminate this approach as a powerful strategy for the synthesis of structurally complex and diverse heterocycles. In this Concept article, we attempt to cover this area of research through a selection of recent versatile examples.
Direct Enantioselective Three‐Component Synthesis of Optically Active Propargylamines in Water
Authors: Ohara Mutsuyo , Hara Yoshichika , Ohnuki Tohru , Nakamura Shuichi 
Published: June 2014

AbstractAn enantioselective three‐component reaction of aldehydes, amines, and alkynes in water by using a bis(imidazoline)–CuI catalysts having a hydrophobic substituent and sodium dodecyl sulfate as a surfactant was developed. The reaction was applied to a broad range of aldehydes and alkynes to give optically active propargylamines with excellent yields (up to 99 %) and enantiomeric excesses (up to 99 % ee).
Polydopamine—An Organocatalyst Rather than an Innocent Polymer
Authors: Mrówczyński Radosław , Bunge Alexander , Liebscher Jürgen 
Published: June 2014

AbstractPolydopamine (PDA) is easily available by oxidation of dopamine and is widely used for persistent coatings of various materials. It is hitherto considered to be inert in many interesting biomedical and other applications. Results presented here, reveal an unexpected behavior of polydopamine as an organocatalyst in direct aldol reactions under mild conditions. Evidence was found for dual catalysis making use of amino and phenolic hydroxy groups found in PDA. Thus scientists must be aware that PDA is not an innocent polymer and can cause unwanted side effects in important applications, such as in biomedicine or as supports in catalysis.
Hydrophobic Modification of Pd/SiO2@Single‐Site Mesoporous Silicas by Triethoxyfluorosilane: Enhanced Catalytic Activity and Selectivity for One‐Pot Oxidation
Authors: Nakatsuka Kazuki , Mori Kohsuke , Okada Shusuke , Ikurumi Shohei , Kamegawa Takashi , Yamashita Hiromi 
Published: June 2014

AbstractTo enhance the catalytic activity in a selective one‐pot oxidation using in‐situ generated H2O2, a hydrophobically modified core–shell catalyst was synthesized by means of a simple silylation reaction using the fluorine‐containing silylation agent triethoxyfluorosilane (TEFS, SiF(OEt)3). The catalyst consisted of a Pd‐supported silica nanosphere and a mesoporous silica shell containing isolated TiIV and F ions bonded with silicon (SiF bond). Structural analyses using XRD and N2 adsorption–desorption suggested that the mesoporous structure and large surface area of the mesoporous shells were retained even after the modification. During the one‐pot oxidation of sulfide, catalytic activity was enhanced significantly by increasing the amount of fluorine in the shell. A hydrophobic surface enhanced adsorption of the hydrophobic reactant into the mesopore, while the less hydrophobic oxygenated products efficiently diffused into the outside of the shell, which improved the catalytic activity and selectivity. In addition, the present methodology can be used to enhance the catalytic activity and selectivity in the one‐pot oxidation of cyclohexane by using an Fe‐based core–shell catalytic system.
The Photo‐Nazarov Reaction: Scope and Application
Authors: Cai Shujun , Xiao Zheming , Shi Yingbo , Gao Shuanhu 
Published: June 2014

AbstractThe reaction conditions and scope of the photo‐Nazarov reaction of aryl vinyl ketones were investigated. In contrast to the conventional acid‐catalyzed methods, this photolytic electrocyclization proceeds in the neutral or basic conditions. Irradiating substrates bearing various aromatic rings, acid‐sensitive groups, cyclohexenyl, cycloheptenyl, and unsaturated pyran with UV‐light (254 nm) smoothly yielded hexahydrofluorenones and related structures. This photo‐Nazarov reaction could also be applicable to the substrates carrying β‐alkyl groups on the enone, which gave corresponding polycyclic rings containing quaternary centers. These photo‐electrocyclized products may prove useful for synthesizing a variety of natural products and their derivatives. Further application of this mild photo‐Nazarov reaction in the synthesis of taiwaniaquinol B was achieved.
Metal‐Free Stabilization of Monomeric Antimony(I): A Carbene‐Supported Stibinidene
Authors: Dorsey Christopher L. , Mushinski Ryan M. , Hudnall Todd W. 
Published: June 2014

AbstractA diamidocarbene was coordinated to an antimony(III) dichloride Lewis acid. Subsequent reduction with magnesium gave a monomeric, formally antimony(I) fragment that is supported by the diamidocarbene. Spectroscopic, crystallographic, and computational analyses demonstrated that the carbene ligand engages the antimony(I) center in π‐backbonding resulting in a short (2.068(7) Å) SbC interaction that is comparable to those observed in known stibaalkenes.
ChemInform Abstract: Self‐Assembly and Photocatalytic Hydrogen Evolution of a Niobium‐Containing Polyoxometalate.
Authors: Yang Zhao‐Xia , Huang Peng , Zhao Liang , Zhang Min , Zhang Yu‐Teng , Su Zhong‐Min 
Published: June 2014

AbstractCs19K2 [Nb4O6 (SiW9Nb3O40)4] Cl·27H2O is hydrothermally synthesized from a mixture of Cs8H[SiW9(NbO2)3O37], KCl, HCl, and H2O (autoclave, pH 2, 160 °C, 3 d, 76% yield).
ChemInform Abstract: Iron‐Catalyzed Reductive Cyclization of 1,6‐Enynes.
Authors: Lin Aijun , Zhang Zhi‐Wei , Yang Jiong 
Published: June 2014

AbstractA FeCl2‐catalyzed cyclization of 1,6‐enynes (I) and (III) is developed using a unique combination of Et2Zn and MgBr2·OEt2 as reagent for the in‐situ‐generation of the catalytically active species.
ChemInform Abstract: Enantioselective Synthesis of α‐Halo‐α‐alkylmalonates via Phase‐Transfer Catalytic α‐Alkylation.
Authors: Hong Suckchang , Kim Minsik , Jung Myunggi , Ha Min Woo , Lee Myungmo , Park Yohan , Kim Mi‐hyun , Kim Taek‐Soo , Lee Jihoon , Park Hyeung‐geun 
Published: June 2014

AbstractThis method gives also access to the precursor of Welch′s HIV‐1 protease inhibitor (VI).
ChemInform Abstract: Synthesis of Bis(halovinyl)benzenes by Catalytic Olefination.
Authors: Muzalevskiy V. M. , Shikhaliev N. G. , Magerramov A. M. , Gurbanova N. V. , Geydarova S. D. , Balenkova E. S. , Shastin A. V. , Nenajdenko V. G. 
Published: June 2014

AbstractThe catalytic olefination of hydrazines of terephthalic (I) and isoterephthalic (XI) aldehydes with several polyhaloalkanes is studied.
ChemInform Abstract: Synthesis of 1‐Haloethenamides from Ynamide Through Halotrimethylsilane‐Mediated Hydrohalogenation.
Authors: Ohashi Kazuhiro , Mihara Shigenori , Sato Akihiro H. , Ide Masataka , Iwasawa Tetsuo 
Published: June 2014

AbstractThe reaction is initiated by HX which is prepared in‐situ from halotrimethylsilane and water.
ChemInform Abstract: Highly Enantioselective Rh‐Catalyzed Alkenylation of Imines: Synthesis of Chiral Allylic Amines via Asymmetric Addition of Potassium Alkenyltrifluoroborates to N‐Tosyl Imines.
Authors: Gopula Balraj , Chiang Chien‐Wei , Lee Way‐Zen , Kuo Ting‐Shen , Wu Ping‐Yu , Henschke Julian P. , Wu Hsyueh‐Liang 
Published: June 2014

AbstractFor the first time, simple N‐tosyl aryl aldimines are used as substrates in the rhodium catalyzed 1,2‐addition reaction with alkenylboron nucleophiles.