bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficiency of Nanoscaled Flow Regulators
Authors: Odeku O. A. , Weber S. , Zimmermann I. 
Published: November 2010

AbstractIn dry powders the particle flow is mainly determined by van der Waals forces. It was proved in systematic studies that in addition to the hydrophilic silica Aerosil® 200 also hydrophobic silicas, various types of carbon black, or precipitated silicas are able to act as flow regulators if these highly aggregated nanomaterials can be broken down into smaller fragments comprising only a few primary particles. To characterize the ability of a given nanomaterial to act as flow regulator, the two terms effectiveness and efficiency were introduced. Effectiveness describes the maximum achievable reduction of the tensile strength by a given concentration of the nanomaterial. The parameter efficiency expresses the mixing time required to achieve the maximum reduction of tensile strength. The efficiency, however, is strongly dependent on the energy brought up by the mixing procedure. This energy is needed to desagglomerate the highly aggregated nanomaterials. Since up to now there is no method to measure these forces directly and methods allowing their indirect determination were looked for.
Enzymatic Racemization of Amines Catalyzed by Enantiocomplementary ω‐Transaminases
Authors: Koszelewski Dominik , Grischek Barbara , Glueck Silvia M. , Kroutil Wolfgang , Faber Kurt 
Published: November 2010

AbstractA strategy for the biocatalytic racemization of primary α‐chiral amines was developed by employing a pair of stereocomplementary PLP‐dependent ω‐transaminases. The interconversion of amine enantiomers proceeded through reversible transamination by a prochiral ketone intermediate, either catalyzed by a pair of stereocomplementary ω‐transaminases or by a single enzyme possessing low stereoselectivity. To tune the system, the type and concentration of a nonchiral amino acceptor proved to be crucial. Finally, racemization could be achieved by the cross‐transamination of two different amines without a requirement for an external amino acceptor. Several synthetically and industrially important amines could be enzymatically racemized under mild reaction conditions.
Polymorph‐Tuned Synthesis of α‐ and β‐Bi2O3 Nanowires and Determination of Their Growth Direction from Polarized Raman Single Nanowire Microscopy
Authors: In Juneho , Yoon Ilsun , Seo Kwanyong , Park Jeunghee , Choo Jaebum , Lee Yonghoon , Kim Bongsoo 
Published: November 2010

AbstractWe report polymorph‐tuned synthesis of α‐ and β‐Bi2O3 nanowires and their single nanowire micro‐Raman study. The single crystalline Bi2O3 nanowires in different phases (α and β) were selectively synthesized by adjusting the heating temperature of Bi precursor in a vapor transport process. No catalyst was employed. Furthermore, at an identical precursor evaporation temperature, α‐ and β‐ phase Bi2O3 nanowires were simultaneously synthesized along the temperature gradient at a substrate. The growth direction of α‐Bi2O3 nanowires was revealed by polarized Raman single nanowire spectra. For thin β‐Bi2O3 nanowires with a very small diameter, the polarized Raman single nanowire spectrum was strongly influenced by the shape effect.
Synthesis of Biaryl Compounds Using Tandem Ruthenium‐Catalyzed Ring‐Closing Metathesis
Authors: Yoshida Kazuhiro , Shida Hiroaki , Takahashi Hidetoshi , Yanagisawa Akira 
Published: November 2010

AbstractTandem ring‐closing enyne metathesis (RCEM)/ring‐closing olefin metathesis (RCM) of tetraenynes with Grubbs second‐generation catalyst, followed by elimination, was found to be a new and efficient synthetic approach to biaryl compounds. A preliminary asymmetric version of this approach, which used homochiral Ru–alkylidene catalysts, is also presented.
Regioisomeric Control Induced by DABCO Coordination to Rotatable Self‐Assembled Bis‐ and Tetraporphyrin α,γ‐Cyclic Octapeptide Dimers
Authors: Hernández‐Eguía Laura P. , Brea Roberto J. , Castedo Luis , Ballester Pablo , Granja Juan R. 
Published: December 2010

AbstractThe design and synthesis of two α,γ‐cyclic octapeptides decorated with one and two Zn–porphyrin units in their periphery is described. In nonpolar organic solvents the α,γ‐cyclic octapeptides quantitatively self‐assemble into Zn–bis‐ or –tetraporphyrin architectures that could act as molecular tweezers. The self‐assembly process, however, is not regioselective and affords a mixture of different regioisomers that are involved in chemical exchange processes. The regioisomers with the Zn–porphyrin units positioned in register with respect to each other are proposed to be the less abundant species in the solution mixture. It has been demonstrated that the coordination of 1,4‐diazabicyclo[2.2.2]octane (DABCO) to the supramolecular bis‐ or tetraporphyrin tweezers is an effective way to achieve regioisomeric control of the self‐assembled mixture of dimers. Thus, DABCO functions as an external molecular trigger and, when used under strict stoichiometric control with respect to the Zn–porphyrin units, provokes the exclusive formation of self‐assembled dimers with a cofacial arrangement of Zn–porphyrin units through the formation of sandwich‐type complexes. The use of excess DABCO fragments the sandwich complexes and affords open dimers of high stoichiometry with DABCO molecules axially monocoordinated to the Zn–porphyrin units, probably as a regioisomeric mixture. In the case of Zn–tetraporphyrin tweezers, the ditopic coordination of DABCO at the two binding sites shows a moderate positive cooperativity factor, αP=5. These assemblies have potential applications as light‐induced energy and electron‐transfer switches regulated by DABCO coordination; such applications would require the introduction of additional chromophores in the cyclic peptide scaffold.
Delayed Fluorescent Emission from Pyrene Doped Phenanthrene Nanoparticles Based on Triplet‐triplet Energy Transfer
Authors: Jiang Ziwen , Zhao Yongsheng , Luo Zhixun , Peng Aidong , Wang Hao , Yao Jiannian 
Published: November 2010

AbstractDoped nanoparticles were prepared from pyrene and phenanthrene using a facile reprecipitation method. The doped nanoparticles presented unique delayed fluorescent emissions of pyrene under the unprotected condition. The ratio of the intensity of delayed fluorescence (IDF) to that of phosphorescence (IP) is about 4:1, which almost keeps unchanged with the decrease of pyrene content at room temperature. The intensity of the delayed fluorescence emissions is dependent on the relative content of pyrene, as well as the aggregation degree of nanoparticles. The delayed emissions are contributed to efficient triplet‐triplet energy transfer from phenanthrene (donor) to pyrene (acceptor). Steady fluorescence measurement have proved that the singlet‐singlet energy transfer process was also existent dominated by the radiation energy transfer mechanism.
Photo Catalytic Degradation of Azo Dyes over Mn2+ Doped TiO2 Catalyst under UV/Solar Light: An Insight to the Route of Electron Transfer in the Mixed Phase of Anatase and Rutile
Authors: Lakshmipathi Naik Gomathi Devi , Kottam Nagaraju , Shivashankar Girish Kumar 
Published: November 2010

AbstractMn2+ ion was doped into the TiO2 matrix and its photocatalytic activity was evaluated for the degradation of a mono azo dye methyl orange (MO) and a di‐azo dye brilliant yellow (BY) under UV/solar light. X‐ray diffraction results revealed the phase transformation from anatase to rutile due to the inclusion of Mn2+ ion into the TiO2 matrix. All the doped catalysts showed a red shift in the band gap to the visible region. The degradation reaction of the dyes was found to be dependent on its structure. It was found that mono azo dye degrades faster than di azo dye under UV/solar light. The rate constant under identical conditions calculated for the degradation of MO is 2.4 times (under UV light) and 4.5 times (under solar light) higher compared to BY. Among the photocatalysts studied, Mn2+(0.06 at.%)‐TiO2 showed higher activity under both UV and solar light illumination. The synergestic effect in the bicrystalline framework of anatase and rutile effectively suppresses the charge carrier recombination and enhances the photocatalytic activity. The degradation reaction was followed by UV‐visible spectroscopy and the photoproducts formed were analyzed by GC‐MS techniques.
Synthesis, Crystal Structure, Spectroscopic, Electrochemical and Antimicrobial Properties of Cu(II) Complex with the Mixed Ligands of 2,9‐Dimethyl‐1,10‐phenanthroline and 4‐Hydroxypyridine‐2,6‐dicarboxylic Acid
Authors: Derikvand Zohreh , Talei Gholam Reza , Aghabozorg Hossein , Olmstead Marilyn M. , Azadbakht Azadeh , Nemati Andya , Gharamaleki Jafar Attar 
Published: November 2010

AbstractA mononuclear Cu(II) complex with mixed ligands, formulated as [Cu(hypydc)(dmp)]·H2O (hypydc=4‐hydroxypyridine‐2,6‐dicarboxylate, dmp=2,9‐dimethyl‐1,10‐phenanthroline), was synthesized and well characterized by single crystal X‐ray diffraction analysis, as well as spectroscopic (IR, UV‐Vis), and electrochemical methods. The Cu(II) atom exhibits a distorted square‐pyramidal geometry. Intermolecular OH···O and CH···O hydrogen bonds, π‐π stacking interactions and CH···π interactions seem to be effective in the stabilization of the crystal structure. The complex was also evaluated for its antimicrobial activity using in vitro microdilution methods. Six standard bacteria and a strain of Candida albicans were used for the antimicrobial activities. There was a very strong activity against Candida albicans and significant activities against Enterococcus fecalis, Listeria monocytogenes, Bacillus cereus and Staphylococcus aureus, indicating important biological activities of the complex.
Spectrofluorimetric Determination and Validation of Biotin in Pure and Dosage Form via Derivatization with 4‐Fluoro‐7‐nitrobenzofurazan
Authors: Sevgi Tatar Ulu 
Published: November 2010

Abstract A simple and highly sensitive spectrofluorimetric method was developed for the determination of biotin in pure and dosage form. The method is based on the derivatization of biotin with 4‐fluoro‐7‐nitrobenzofurazan in borate buffer of pH 9.0 to yield a yellow, fluorescent product. The various chemical conditions that affected the reaction were studied. The method was validated for specificity, linearity, precision, accuracy, recovery and robustness. At optimized experimental conditions, a linear relationship between the fluorescence intensity of the concentration of biotin is observed in the range 45–450 ng/mL. Limit of detection and quantification were 0.038 and 0.114 ng/mL, respectively. The percentage mean recovery was 99.96. The proposed procedure was successfully applied to the determination of biotin in its dosage form with mean recovery of 101.23±1.22 for biotin tablets. The results obtained were in good agreement with those obtained by the reference method.
Regio‐ and Stereo‐selective Synthesis of Peracetylated Carbohydrate Esters of Aromatic Fatty Acid Using p‐Toluenesulfonic Acid as Catalyst
Authors: Zhu Zhenyuan , Li Shengfeng , Liu Rongqiang , Yuan Jing , Wang Haibiao , Zhang Yongmin , Liu Yang 
Published: November 2010

AbstractThis paper describes an efficient synthesis of carbohydrate fatty acid esters based on a highly stereo‐ and regio‐selective esterification. The suitably protected glycosyl was esterified with stearic acid to give mainly the β‐anomer in good yield using p‐toluenesulfonic acid as catalyst. The structures of these compounds were fully confirmed by 1H, 13C NMR, mass spectra and HRMS.
Application of N,N′‐Diiodo‐N,N′‐1,2‐ethandiylbis(p‐toluene sulfonamide) as a New Reagent for Synthesis of 2‐Arylbenzimidazoles and 2‐Arylbenzothiazoles under Solvent‐free Conditions
Authors: Veisi Hojat , Ghorbani‐Vaghei Ramin , Faraji Alireza , Ozturk Turan 
Published: November 2010

AbstractN,N′‐Diiodo‐N,N′‐1,2‐ethandiylbis(p‐toluene sulfonamide) (NIBTS) is a good and new reagent for synthesis of 2‐arylbenzimidazoles and 2‐arylbenzothiazoles at room temperature under solvent‐free condition with good to high yield. Absence of solvent, short reaction times, non‐corrosive, operational simplicity and environmentally friendliness are the main advantages of this procedure.
Catalysis by L‐Lysine: A Green Method for the Condensation of Aromatic Aldehydes with Acidic Methylene Compounds in Water at Room Temperature
Authors: Zhang Yan , Sun Cuizhi , Liang Jun , Shang Zhicai 
Published: November 2010

AbstractThe condensation of aromatic aldehydes with acidic methylene compounds such as ethyl benzoylacetate, 2,4‐pentanedione and dimedone proceeded efficiently in pure water in the presence of L‐lysine at room temperature. Interestingly, there are two different reaction mechanisms taking place under the same green catalyst system. This provides a green and mild synthetic method for the preparation of these two classes of compounds.
Synthesis of Fe3O4 Microspheres‐Supported Catalysts for Suzuki Coupling Reaction
Authors: Zhang Yanqi , Wei Xianwen , Yao Zijian 
Published: November 2010

AbstractTwo new Fe3O4 microspheres‐supported semi‐homogeneous catalysts, namely Fe3O4‐G4‐polyaminoamido (PAMAM) dendrimers‐Pd(0) and Fe3O4‐polyethylene glycols (PEGs)‐Pd(0) were synthesized and characterized by X‐ray powder diffraction, infrared spectrum, scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and thermal gravimetric analysis, which can catalyze Suzuki coupling reactions. The performance of catalysts was tested for the reactions of aryl halides with phenyl boronic acid and compared with a heterogeneous catalyst Fe3O4‐(3‐aminopropyl)triethoxysilane (APTS)‐Pd(0), in which Fe3O4‐G4‐PAMAM dendrimers‐Pd(0) shows the best activity among the three catalysts. The order of the catalytic activities is Fe3O4‐G4‐PAMAM dendrimers‐Pd(0)>Fe3O4‐PEGs‐Pd(0)>Fe3O4‐APTS‐Pd(0). The catalysts can be quickly and completely recovered by simply applying a magnet of 105 mT and the efficiencies remain unaltered even after four recycles.
Isomeric Effect on H/D Exchange of Resveratrol Studied by NMR Spectroscopy
Authors: Jiang Haipeng , Fang Hanjun , Jiang Ling , Zheng Limin , Wang Nian , Zheng Anmin , Deng Feng , Liu Maili 
Published: November 2010

AbstractResveratrol (3,5,4′‐trihydroxylstilbene), a phytoalexin in response to injury or fungal attack, is found in grapes and other food products. It has been well documented that the compound has beneficial effects as hypolipidemic, anticancer, antiviral, neuroprotective, antiaging, and anti‐inflammatory natural active principle. It was observed that both trans‐ and cis‐resveratrols undergo hydrogen‐deuterium (H/D) exchange at H‐2,6 and H‐4 positions of the A‐ring. The exchange rates were determined by 1H NMR spectroscopy. The results reveal that the exchange rates are configuration and pH dependent. Derivative of 2‐O‐β‐D‐glucoside can significantly speed up the H/D exchange reactions for both isomers. The trans‐resveratrol experiences faster H/D exchanging than the cis‐resveratrol. Such isomeric effect is possibly due to the factor that the trans‐resveratrol is in favor of forming larger/super conjugative system and has less spatial interference. Theoretical calculation shows that electronegativity at these positions is in the order of H‐2,6>H‐4, which is in consistent with the exchange rates observed by NMR. The results may be of help in understanding the properties of resveratrol, and in analysis of resveratrol in natural products or body fluids using mass spectroscopy that occasionally requires stable deuterium isotope labeling.
A Simple and Sensitive Method for the Detection of Trace Pb(II) and Cd(II) based on Nafion‐coated Antimony Film Electrode
Authors: Xu He , Yang Ping , Zheng Qiaoli , Liu Jianshe , Jin Litong 
Published: November 2010

AbstractNafion‐coated antimony film electrode (NCAFE) was prepared in situ by simultaneously plated antimony with analytes, and applied to the determination of trace Pb(II) and Cd(II) in non‐deaerated solutions by differential pulse anodic stripping voltammetry (DPASV). Various experimental parameters, which influenced the response of the NCAFE to those metals, were thoroughly optimized and discussed. The results indicated that the sensitivity and resistance to surfactants at the NCAFE were remarkably improved with relative to the antimony film electrode (AFE). In the presence of 5 mg·L−1 gelatin, the peak heights at the NCAFE showed 4‐fold enhancement for Pb and a 9‐fold enhancement for Cd over a bare AFE. Reproducibility of the sensor was satisfactory, and the relative standard deviations were 4.8% for 20 μg·L−1 Pb and 3.2% for 25 μg·L−1 Cd (n=15) with preconcentration time of 180 s. The determination limits (S/N=3) of this sensor were determined to be 0.15 μg·L−1 for Pb and 0.30 μg·L−1 for Cd with accumulation time of 300 s. The NCAFE was successfully applied to determining Pb(II) and Cd(II) in vegetable and water samples with satisfactory results.
Development of High Performance Liquid Chromatography Method for Costunolide and Dehydrocostuslactone in Mice Plasma and Tissues: Application to Pharmacokinetic Study
Authors: Hu Fangdi , Feng Shilan , Wu Yuqiong , Bi Yingyan , Cui Fang , Li Yongjie , Wang Chunming 
Published: November 2010

AbstractA simple and sensitive high performance liquid chromatographic (HPLC) method for simultaneous determination of costunolide and dehydrocostuslactone in mice plasma and tissues was developed and validated. Costunolide and dehydrocostuslactone were extracted into acetonitrile and separated using an isocratic mobile phase, on a Hypersil ODS C18 column. The effluent was monitored by UV detector at 210 nm and at a flow rate of 1.0 mL· min−1 and 25°C. The linearity ranges of proposed method were 0.223–8.920 µg·mL−1 for costunolide and 0.227–9.080 µg·mL−1 for dehydrocostuslactone. The intra‐day and inter‐day RSD of the assay method for the two components were less than 5%, and mean recovery was within the 86.5% to 101.8% range. The method was found to be precise, accurate, and specific during the study. The method was successfully applied for pharmacokinetic study of costunolide and dehydrocostuslactone after application of ethanol extraction of Muxiang (EEM) in mice.
Shape‐controlled Synthesis of Nanostructure Ramsdellite‐type Manganese Oxide at Atmospheric Pressure
Authors: Qiu Guohong , Wang Jun , Zhao Wei , Feng Xionghan , Tan Wenfeng , Zhang Qin , Liu Fan 
Published: November 2010

AbstractRamsdellite (R‐MnO2) was prepared by oxidizing bivalent manganese salts, such as MnCl2, MnSO4 and Mn(NO3)2, with NaClO solution using a refluxing process at atmospheric pressure. The products were characterized by X‐ray diffraction, fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and flame photometry. R‐MnO2 microstructure and morphology were controlled by adjusting reaction temperature, the amount of hydrochloric acid (HCl) and anions of bivalent manganese salts. Ramsdellite grain was formed with three different bivalent manganese salts oxidized by NaClO solution at 60°C, and increased with the increase of reflux temperature. R‐MnO2 nanorod and nanowire crystals were obtained when MnCl2 and MnSO4 were used as bivalent manganese salts at 100°C respectively. Nanosized flake of R‐MnO2 came into being when Mn(NO3)2 was applied at 80°C. When 30 mmol MnCl2 was oxidized by 60 mmol NaClO solution with adding 20 mmol HCl in refluxing solution, specific surface area of R‐MnO2 grain obtained at 60°C was greater than 140 m2/g, and the self‐assembly of nanorod bundles into interesting flowerlike architectures was achieved at 100°C. The process of dissolution‐precipitation equilibrium might be the primary cause for the morphology transformation.
How to assess cytotoxicity of (iron oxide‐based) nanoparticles. A technical note using cationic magnetoliposomes
Authors: Soenen Stefaan J.H. , De Cuyper Marcel 
Published: December 2010

AbstractThe range of different types of nanoparticles and their biomedical applications is rapidly growing, creating a need to thoroughly examine the effects these particles have on biological entities. One of the most commonly used nanoparticle types is iron oxide nanoparticles, which can be used as MRI contrast agents. The main research topic is the in vitro labeling of cells with iron oxide nanoparticles to render the cells detectable for MRI upon in vivo transplantation. For the correct evaluation of cell function and behavior in vivo, any effects of the nanoparticles on the cells must be completely ruled out. The present work provides a technical note where a detailed overview is given of several assays that could be useful to determine nanoparticle toxicity. The assays described focus on (i) nanoparticle internalization, (ii) immediate cell toxicity, (iii) cell proliferation, (iv) cell morphology, (v) cell functionality and (vi) cell physiology. Potential pitfalls, appropriate controls and advantages/disadvantages of the different assays are given. The main focus of this work is to provide a detailed guide to help other researchers in the field interested in setting up nanoparticle‐toxicity studies. Copyright © 2010 John Wiley & Sons, Ltd.
A phase 2 study of irinotecan, cisplatin, and simvastatin for untreated extensive‐disease small cell lung cancer
Authors: Han Ji‐Youn , Lim Kun Young , Yu Sun Young , Yun Tak , Kim Heung Tae , Lee Jin Soo 
Published: November 2010

AbstractBACKGROUND:The objective of this study was to investigate the efficacy of simvastatin in combination with irinotecan and cisplatin in chemotherapy‐naive patients with extensive‐disease small‐cell lung cancer (ED‐SCLC).METHODS:In this phase 2 study, 61 patients received treatment with irinotecan (65 mg/m2) and cisplatin (30 mg/m2) on Days 1 and 8 every 3 weeks until either death or disease progression occurred. Patients also received oral simvastatin (40 mg daily) during the course of chemotherapy. The primary endpoint was 1‐year survival. Secondary endpoints included the response rate (RR), progression‐free survival (PFS), and toxicity.RESULTS:The 1‐year survival rate was 39.3%. The median overall survival (OS) was 11 months, and the median PFS was 6.1 months. Overall, the RR was 75%. The most common grade 3/4 toxicity was neutropenia (67%). Efficacy of the treatment was associated significantly with smoking status. Compared with never‐smokers, ever‐smokers had a better RR (40% vs 78%; P = .01), a longer PFS (2.5 months vs 6.4 months; P = .018), and had a trend toward an improved OS (9.0 months vs 11.2 months; P = .095). The effect of smoking on survival was apparent when ever‐smokers were subdivided according to pack‐years (PY) of smoking. Ever‐smokers who had smoked >65 PY had a significantly longer OS compared with ever‐smokers who had smoked ≤65 PY or never‐smokers (20.6 months vs 10.6 months vs 9.0 months, respectively; log‐rank P = 0.032). In multivariate analysis, PY >65 was predictive of longer survival (hazard ratio, 0.280; 95% confidence interval, 0.113‐0.694).CONCLUSIONS:The current results indicated that simvastatin in combination with irinotecan and cisplatin did not improve the survival of patients with ED‐SCLC. Although the subgroup analysis by smoking status was exploratory, the addition of simvastatin to irinotecan and cisplatin may improve the outcome of heavy smokers with ED‐SCLC. Cancer 2011. © 2010 American Cancer Society.