bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and Characterization of a New Quercetin‐bonded Stationary Phase for High Performance Liquid Chromatography
Authors: Li Laisheng , Fang Yishan , Chen Hong , Zhang Yang 
Published: May 2012

AbstractA quercetin‐bonded silica gel stationary phase (QUSP) containing natural flavonoid ligand was first prepared viaγ‐glycidoxypropyltrimethoxysilane (KH‐560) as a coupling reagent for high‐performance liquid chromatography. Its chemical structure was characterized by Fourier infrared spectroscopy, elemental analysis, thermal thermogravimetry and13C cross polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR). The chromatographic property of QUSP was systematically evaluated by using neutral, basic and acidic aromatic compounds as probes. In order to clarify its retention mechanism, a comparative study of QUSP with conventional octadecylsilyl‐bonded stationary phase (ODS) was also carried out under the same conditions. The results showed that the new quercetin‐bonded phase exhibited an excellent reversed‐phase chromatographic property with relatively weak hydrophobicity. However, it has an advantage over ODS in the fast separation of polar aromatic compounds because the quercetin ligand could provide various sites besides hydrophobicity, such as hydrogen bonding, dipole‐dipole, π‐π staking and charge transfer interactions. QUSP was performed in the baseline separations of ionized polar basic or acidic compounds, including pyridines, anilines, pyrimidines, purines and phenols with symmetric peak shape in common mobile phases without buffer salt within relatively short time. The natural ligands from herbs are readily available and contain a variety of active sites, which facilitate the exploration of industrial chromatographic separation materials for green products.
Synthesis and Cyclization of 8‐Formyl‐2‐(phenoxymethyl)quinoline‐3‐carboxylic Acids
Authors: Gao Wentao , Zhao Zhigang , Li Yang , Yan Yan , Li Feng 
Published: May 2012

AbstractA facile synthesis of a series of new quinoline‐8‐carbaldehyde compounds, namely 8‐formyl‐2‐(phenoxymethyl)quinoline‐3‐carboxylic acids (4a–4h) and 13‐oxo‐6,13‐dihydro[1]benzoxepino[3,4‐b]quinoline‐8‐carbaldehyde (5a–5g) is described, involving the one‐pot synthesis reaction of ethyl 2‐(chloromethyl)‐8‐formylquinoline‐3‐carboxylate (3) with substituted phenols followed by the intramolecular cyclization reaction via the treatment with polyphosphoric acid (PPA). Quinoline‐8‐carbaldehydes 4a–4h and 5a–5g are novel and their structures were supported by IR, 1H NMR, 13C NMR, MS and elemental analysis.
A Highly Sensitive Electrochemical Impedance Spectroscopy Immunosensor for Determination of 1‐Pyrenebutyric Acid Based on the Bifunctionality of Nafion/Gold Nanoparticles Composite Electrode
Authors: Yang Ping , Zheng Qiaoli , Xu He , Liu Jianshe , Jin Litong 
Published: May 2012

AbstractA simple, highly sensitive and label‐free electrochemical impedance spectroscopy (EIS) immunosensor was developed using Nafion and gold nanoparticles (nano‐Au/Nafion) composites for the determination of 1‐pyrenebutyric acid (PBA). Under the optimal conditions, the amount of immobilized antibody was significantly improved on the nano‐Au/Nafion electrode due to the synergistic effect and biocompatibility of Nafion film and gold nanoparticles composites. The results showed that the sensitivity and stability of nano‐Au/Nafion composite electrode for PBA detection were much better than those of nano‐Au modified glassy carbon electrode (nano‐Au/GCE). The plot of increased electron transfer resistances (Rets) against the logarithm of PBA concentration is linear over the range from 0.1 to 150 ng·mL−1 with the detection limit of 0.03 ng·mL−1. The selectivity and accuracy of the proposed EIS immunosensor were evaluated with satisfactory results.
Facile Synthesis of Dendritic Hydroxyl‐terminated Cyanuric Chloride Derivatives and Their Properties
Authors: Lin Xiuxiu , Zhou Jianhua , Xu Dongmei 
Published: May 2012

AbstractNovel dendritic compounds G1.5(OH)4 and G1.5(OH)8 with peripheral hydroxyl were synthesized under mild conditions from cyanuric chloride, ethylene diamine, ethanolamine and diethanolamine. The products could be separated and purified through dispersion and precipitation in organic solvents with good yields (over 93.0%) and high purity (above 98.0%, HPLC). The structures of the products were characterized by IR, MS, 1 H NMR and elementary analysis. G1.5(OH)4 and G1.5(OH)8 could be dissolved in polar solvents such as methanol, water and dimethylsulfoxide. TGA analysis showed that G1.5(OH)4 and G1.5(OH)8 had good thermo stability. The aqueous solutions of G1.5(OH)4 and G1.5(OH)8 exhibited low surface tension.
Facile Synthesis of 3‐Substituted Isoquinolines Derivatives via Microwave‐assisted Tandem Three‐component Coupling Cyclization
Authors: Lin Long , Wu Qiongyou , Huang Shaowei , Yang Guangfu 
Published: May 2012

AbstractA novel three‐component reaction of o‐bromobenzaldehyde, terminal alkynes and tert‐butyl amine has been established, which proceeded smoothly to give 3‐substituted isoquinolines in good yields in the presence of palladium/copper catalysts under microwave irradiation.
A New Copper(I) Complex Based on Imidazole and Triphenylphosphine Ligands: Synthesis, Structure, Third‐Order NLO, and Fluorescence Properties
Authors: Liu Faqian , Jin Yanling , Liu Baocheng , Li Rongxun , Deng Yueyi , Li Weihua , Jian Fangfang 
Published: May 2012

AbstractA new candidate [Cu(PPh3)2Him]Br (1, PPh3=triphenylphosphine, Him=1‐H‐imidazole) for nonlinear optical (NLO) materials has been synthesized and characterized crystallographically. The third‐order NLO optical properties were measured by the Z‐scan technique with an 8 ns pulsed laser at 532 nm. Compound 1 exhibits strong NLO absorptive abilities [α2=(61±5)×10−12] and effective self‐focusing performance [n2=(15±3)×10−18 m2·W−1] in 1.01×10−4 mol·dm−3 DMF solution. The compound also exhibits luminescence in DMF solution at room temperature and shows narrow emission with maximum at 382 nm. The electronic structure and photoluminescent process were investigated by means of TD‐DFT calculations. The results suggest that the contribution to the frontier orbitals from the CuBr δ bond plays a crucial role in its linear optical properties, and the origin of luminescence is attributable to the π∗︁→n transitions.
A Novel Method for Biomimetic Synthesis of Mannich Bases
Authors: Guo Yuan , An Jing , Lu Zhenhuan , Peng Mengjiao 
Published: May 2012

AbstractSince the early studies of Mannich, Mannich reaction has become an important tool for the synthesis of new compounds. Mannich bases can be either directly employed or used as intermediates. In this work, the one‐carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. 1,3‐Dimethylimidazolidine as a new tetrahydrofolate coenzyme model at formaldehyde oxidation level was used to react with ketone having active hydrogen atoms and amine to give the corresponding Mannich base in good yield by a covert Mannich reaction. A novel method for biomimetic synthesis of various Mannich bases is provided.
Efficient Synthesis of the Functionalized Spiro[indoline‐3,4′‐pyridine] via Four‐component Reaction
Authors: Sun Jing , Wu Qun , Zhang Lijuan , Yan Chaoguo 
Published: May 2012

AbstractAn efficient synthetic procedure for the functionalized spiro[indoline‐3,4′‐pyridine] was developed via the four‐component reactions of arylamines, acetylenedicarboxylates, isatins and malononitrile with triethylamine as the base catalyst. The advantages of this reaction are using common starting material, mild reaction conditions, broad scope of reactants and operational simplicity.
Dimedone‐catalyzed Addition of Amines into Cyano Group: Facile Synthesis of Thiazol‐2‐yl Substituted E‐Acrylonitriles
Authors: Zhu Weijun , Tu Xingchao , Feng Hui , Tu Mansu , Jiang Bo , Wu Feiyue , Tu Shujiang 
Published: May 2012

AbstractAn efficient dimedone‐catalyzed synthesis of highly functionalized thiazol‐2‐yl substituted E‐acrylonitrile derivatives has been established through two‐step reaction of α‐thiocyanate ketones with malononitrile and amines. The α‐thiocyanate ketones were subjected with malononitrile to provide thiazol‐2‐ylidenemalononitrile derivatives, followed with various amines in the present of dimedone to yield the final thiazol‐2‐yl substituted acrylonitrile derivatives.
Synthesis and Insecticidal Activities of Novel Phthalic Acid Diamides
Authors: Yan Tao , Li Yuxin , Li Yongqiang , Wang Duoyi , Chen Wei , Liu Zhuo , Li Zhengming 
Published: May 2012

AbstractIn order to discover novel insecticides with the new action mode on ryanodine receptor (RyR), a series of novel phthalic acid diamide derivatives were designed and synthesized. All compounds were characterized by 1H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that some title compounds exhibited excellent insecticidal activities against Mythimna separata, Spodoptera exigua, and Plutella xylostella. The title compound 3‐nitro‐N‐cyclopropyl‐N′‐[2‐methyl‐4‐(perfluoropropan‐2‐yl)phenyl]phthalamide (4a) was more efficient against diamondback moths than the control (chlorantraniliprole). The effects of some title compounds on intracellular calcium of neurons from the Spodoptera exigua proved that the title compounds were RyR activators.
New Soluble Polyimides with High Optical Transparency and Light Color Containing Pendant Trifluoromethyl and Methyl Groups
Authors: Wang Chenyi , Zhao Xiaoyan , Li Guang 
Published: May 2012

AbstractA new aromatic diamine containing trifluoromethyl and methyl groups, namely α,α‐bis(4‐amino‐3‐methylphenyl)‐4‐(trifluoromethyl)phenylmethane (1), was synthesized from 2‐methylaniline and 4‐(trifluoromethyl)benzaldehyde. A series of fluorinated polyimides (PIs) were prepared from the diamine with four commercially available aromatic tetracarboxylic dianhydrides using a one‐step high‐temperature polycondensation procedure. These obtained PIs showed excellent solubility, with the dissolvability at a concentration of 10 wt% in most solvents, and they could afford flexible and strong films. Thin films of these PIs exhibited high optical transparency and light color, with the cutoff wavelength at 324–357 nm and transmittance higher than 74% at 450 nm. Moreover, these PIs possessed eminent thermal stability and good mechanical properties.
Three‐Component Cucurbit[6]uril Framework with 1:2 Host‐Guest Motif and Dimeric Boric Acid
Authors: Wang Meng , Li Xiang , Liu Li 
Published: May 2012

AbstractThree‐component framework of cucurbit[6]uril, 3‐(1‐methylimidazolium‐3‐yl)propane‐1‐sulfonate and boric acid has been constructed. The crystal structure reveals 1:2 host‐guest motif of cucurbit[6]uril and 3‐(1‐methyl‐imidazolium‐3‐yl)propane‐1‐sulfonate, demonstrating both cation binding of imidazolium moiety and anion binding of sulfonate moiety for the first time. Incorporation of dimeric boric acid facilitates the formation of metal‐free three‐dimensional framework.
Silicon‐Included Graphite Films Prepared by Thermally Induced CVD with a (C6F5)4Si Precursor
Authors: Bakovets Vladimir V. , Zelenina Ludmila N. , Levashova Tatiana M. , Uskov Evgeniy M. 
Published: May 2012

AbstractSilicon‐included graphite films obtained by thermally induced (T)CVD from tetrakis(pentafluorephenyl)silane as a precursor are characterized by X‐ray diffraction (XRD), X‐ray microprobe analysis (XMA), X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Raman spectroscopy (RS). It is shown that Si‐included graphite films are produced in H2 or Ar flow at 500–600 °C. Air storage of the films causes a silicon oxidation, partly resulting in graphite with the inclusion of SiOx. Using the Van der Pauw method, the conductivity of the films is shown to be p‐type, the mobility of charge carriers is about 0.4 cm2 V−1 c−1, and their concentration is 1019 cm−3.
Utility‐optimal cross‐layer resource allocation in distributed wireless cooperative networks
Authors: Cui Haixia , Wei Gang , Zhang Han , Zhong Qinghua 
Published: May 2012

SUMMARYIn this paper, we propose a distributed cross‐layer resource allocation algorithm for wireless cooperative networks based on a network utility maximization framework. The algorithm provides solutions to relay selections, flow pass probabilities, transmit rate, and power levels jointly with optimal congestion control and power control through balancing link and physical layers such that the network‐wide utility is optimized. Via dual decomposition and subgradient method, we solve the utility‐optimal resource allocation problem by subproblems in different layers of the protocol stack. Furthermore, by introducing a concept of pseudochannel gain, we model both the primal direct logical link and its corresponding cooperative transmission link as a single virtual direct logical link to simplify our network utility framework. Eventually, the algorithm determines its primal resource allocation levels by employing reverse‐engineering of the pseudochannel gain model. Numerical experiments show that the convergence of the proposed algorithm can be obtained and the performance of the optimized network can be improved significantly. Copyright © 2012 John Wiley & Sons, Ltd.
Multi‐Layered hypertrophied MEE formation by microtubule disruption via GEF‐H1/RhoA/ROCK signaling pathway
Authors: Kitase Yukiko , Shuler Charles F. 
Published: May 2012

AbstractBackground: Formation of the secondary palate is complex and disturbance during palatal fusion may result in cleft palate. The processes of adhesion, intercalation, and disappearance of medial edge epithelia (MEE) are characterized by morphological changes requiring dynamic cytoskeletal rearrangement. Microtubules are one of the cytoskeletal elements involved in maintenance of cell morphology. Microtubule‐disrupting drugs have been reported to cause craniofacial malformations including cleft palate. The mechanisms underlying the failure of palatal fusion remain poorly understood. We evaluated the effect of nocodazole (NDZ), a drug that disrupts microtubules, on palatal fusion in organ culture. Results: NDZ caused failure of palatal fusion due to the induction of a multi‐layered hypertrophied MEE in the mid‐region of the secondary palatal shelves. Microtubule disruption increased RhoA activity and stress fiber formation. Pharmacological inhibition of the RhoA/ROCK pathway blocked multi‐layered MEE formation. Partial prevention of hypertrophied MEE was observed with Y27632 and cytochalasin, but not with blebbistatin. NDZ induced re‐localization of GEF‐H1 into cytoplasm from cell–cell junctions. Conclusions: The present study provided evidence that the GEF‐H1/RhoA/ROCK pathway plays a pivotal role in linking microtubule disassembly to the remodeling of the actin cytoskeleton, which resulted in a multi‐layered hypertrophied MEE and failure of palatal fusion. Developmental Dynamics 241:1169–1182, 2012. © 2012 Wiley Periodicals, Inc.
Characterization of small RNAs in X. tropicalis gastrulae
Authors: Faunes Fernando , Almonacid Leonardo I. , Melo Francisco , Larrain Juan 
Published: May 2012

AbstractHere, we report and characterize deep sequencing data and bioinformatics analysis of small RNAs from X. tropicalis gastrula. A total of 17,553,124 reads with perfect match to the genome derived from 2,616,053 unique sequences were identified. Seventy‐seven percent of theses sequences were not found in previous reports from X. tropicalis oocytes and somatic tissues. Bioinformatics analyses indicate that a large fraction of the small RNAs are PIWI‐interacting RNAs. Up to 23.9% of small RNAs mapped to transposable elements and 27% to genic regions. Most of the abundant transposon‐derived small RNAs are found in oocyte and gastrula libraries, suggesting that transposons also need to be silenced during early embryonic development. Importantly, novel clusters of piRNAs whose expression is activated after zygotic transcription begins were identified in the genome of X. tropicalis. Additionally, miRNAs were also identified and many of them are not present in oocytes, suggesting that miRNA expression is stage‐specific. To the best of our knowledge, this is the first high throughput data release and bioinformatics characterization of small RNAs during Xenopus early embryonic development. genesis 50:572–58, 2012. © 2012 Wiley Periodicals, Inc.
Common use of anticholinergic medications in older patients with schizophrenia: findings of the Research on Asian Psychotropic Prescription Pattern (REAP) study, 2001–2009
Authors: Xiang Yu‐Tao , Dickerson Faith , Kreyenbuhl Julie , Ungvari Gabor S. , Wang Chuan‐Yue , Si Tian‐Mei , Lee Edwin H. M. , Chiu Helen F. K. , Lai Kelly Y. C. , He Yan‐Ling , Yang Shu‐Yu , Chong Mian‐Yoon , Tan Chay‐Hoon , Kua Ee‐Heok , Fujii Senta , Sim Kang , Yong Michael K. H. , Trivedi Jitendra K. , Chung Eun‐Kee , Udomratn Pichet , Chee Kok‐Yoon , Sartorius Norman , Shinfuku Naotaka 
Published: May 2012

ObjectiveThis study surveyed the use of anticholinergic medications (ACMs) in older Asian patients with schizophrenia and examined its demographic and clinical correlates.MethodA total of 1452 hospitalized patients with schizophrenia aged 55 years or older in nine Asian countries and territories were surveyed between 2001 and 2009. The cross‐sectional data of patients' socio‐demographic and clinical characteristics and the prescriptions of antipsychotic drugs and ACM were recorded using a standardized protocol and data collection procedure.ResultsThe frequency of ACM prescription was 64.6% in the pooled sample, with 72.4%, 61.9%, and 59.5% in 2001, 2004, and 2009, respectively. Multiple logistic regression analysis of the whole sample revealed that patients on ACM had a higher dose of antipsychotic medications, and were more likely to have extrapyramidal side effects and receive first‐generation antipsychotic medications.ConclusionsAnticholinergic medications were frequently used in older Asian patients with schizophrenia. Considering the potential side effects of ACM, the rationale for their widespread use in this patient population should be revisited. Copyright © 2012 John Wiley & Sons, Ltd.
A Return on Investment Assessment Model for a Mobile User Interface Project at the Predevelopment Stage
Authors: Kim Min‐Jeong , Park Jonghun 
Published: May 2012

AbstractWe present a new approach for assessing the business performance of a mobile user interface (UI) project at its predevelopment stage. Traditionally, the performance measurement of a mobile UI is made from the perspective of usability. Yet, as the number of mobile phone users is rapidly increasing, and, given that stakeholders are beginning to realize the importance of the UI, there is a growing demand to measure its business performance quantitatively as well as qualitatively. This article presents a model that can facilitate Return on Investment (ROI) estimations pertaining to the development of a mobile UI before the service with the new UI is launched. We base our method on stated preference data for the purpose of applying a conjoint analysis. Subsequently, we evaluate the viability of the proposed model quantitatively by comparing the estimated ROI at the predevelopment stage with the actual sales revenue achieved after the launch of the service. The proposed model was successfully applied to real‐world mobile UI design projects at Korea Telecom. Its benefits are demonstrated here through a case study. © 2012 Wiley Periodicals, Inc.
The influence of salinity on hysteresis of soil water‐retention curves
Authors: Ma Kuo‐Chen , Lin Yong‐Jun , Tan Yih‐Chi 
Published: May 2012

AbstractTaiwan is surrounded by the sea, and the southwestern seashores are suffering from a growing land subsidence problem caused by the excessive extraction of groundwater. There is also very serious intrusion by seawater along the coastline. These circumstances obstruct any land use, soil remediation or agriculture development in the area. When seawater intrudes, salt gets into the soil. The infiltration, evapotranspiration and the distribution of salinity in the unsaturated soil become a very complex problem. It is vital to investigate the hysteresis of soil water‐retention curves, combined with the salinity in these areas. Therefore, this study's main focus will be the calibration of variations in salinity and their effect on the hysteresis of soil water‐retention curves. In the wetting processes, the salty soil water‐retention curves undergo an upper shift compared with the original soil water‐retention curves because of the higher tension of saltwater. In the drying processes, there is also an upper shift compared with the original curves because the salinity influences the air‐entry pressure. The saltwater's high salinity causes the hysteresis of soil water‐retention curves to experience a greater shift. The changes in salinity also cause changes to the hysteresis curves’ shape factors, which conforms to Huang's model (developed by Huang H.C., Y.C. Tan, C.W. Liu, and C.H. Chen in 2005), the values of α and n. The value of α decreases with the increased salinity. The trend of the n value presents an irregular result. A linear regression of the αw and αd values was advanced where the R‐square values of αw and αd exceeded 0.97. Copyright © 2012 John Wiley & Sons, Ltd.
On the role of surface roughness in the corrosion of pure magnesium in vitro
Authors: Nguyen T. L. , Blanquet A. , Staiger M. P. , Dias G. J. , Woodfield T. B. F. 
Published: May 2012

AbstractThe relationship between surface roughness and degradation behavior in magnesium (Mg) biomaterials is still a controversial issue. This study aims to clarify the relationship between surface roughness and corrosion rate of pure Mg. Pure Mg samples with surface roughness values (Ra) of 0.59, 2.68, and 9.12 μm were cast using an indirect solid‐free form fabrication method. The in vitro corrosion behavior was evaluated using hydrogen evolution, mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. It was confirmed that surface roughness had a significant influence on the corrosion rate of pure Mg, with increasing roughness resulting in an accelerated corrosion rate. However, pitting corrosion was not observed, suggesting that surface roughness does not affect the pitting potential of Mg. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Antibacterial effect of a resin incorporating a novel polymerizable quaternary ammonium salt MAE‐DB against Streptococcus mutans
Authors: Huang Li , Sun Xiang , Xiao Yu‐Hong , Dong Yan , Tong Zhong‐Chun , Xing Xiao‐Dong , Li Fang , Chai Zhi‐Guo , Chen Ji‐Hua 
Published: May 2012

AbstractThe antibacterial properties of resins incorporating MAE‐DB and the underlying mechanisms of action were evaluated. Antibacterial effects against Streptococcus mutans were tested using the film contact method, with accumulation and membrane integrity observed by scanning electron microscopy and confocal laser scanning microscopy, respectively. Quantitative PCR was used to determine expression of the S. mutans glucosyltransferase B (gtfB) gene on the surface of resins containing 10% MAE‐DB. Bacterial growth was inhibited on resin containing 10% MAE‐DB as compared with the control at 1 day, 7 days, 30 days, or 180 days (p < 0.05). For the 10%‐MAE‐DB resin, no significant differences in bacterial viability were found regardless of the time of incubation (p > 0.05). The number of bacteria attached to resin containing 10% MAE‐DB was considerably lower than the control. The proportion of bacteria with damaged cell membranes was increased in the experimental resin over controls. Expression of gtfB was reduced by 10% MAE‐DB compared with the control (p < 0.05). These findings demonstrate that MAE‐DB can be incorporated into resin materials at sufficient concentrations for long‐term antibacterial effects against S. mutans after polymerization by attenuating gtfB expression and impairing membrane integrity. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.