bluuebunny/crossref_metadata_2025_split huggingface dataset:
Verstärken von Stahlbetonstützen mit textilbewehrtem Beton
Authors: Ortlepp Regine , Curbach Manfred 
Published: September 2009

AbstractDer Aufsatz beschreibt die Ergebnisse experimenteller Untersuchungen zur Wirkung einer Textilbetonverstärkung an 2 m langen Stützen mit und ohne innen liegender Stahlbewehrung. Die Verstärkung mit textilbewehrtem Beton wurde auf zwei verschiedene Weisen ausgeführt, sowohl als vollständige Umwicklung über die gesamte Länge der Stützen als auch als teilweise Verstärkung über eine Länge von 30 cm in den Lasteinleitungsbereichen. Die einzelnen Anteile am Tragverhalten der verstärkten Stützen wurden untersucht. Ein einfaches Berechnungsmodell wird angegeben.Strengthening of Columns using Textile Reinforced Concrete (TRC)In the context of rehabilitation and repair works or in the course of usage changes of existing buildings the planning engineer frequently is confronted with the task of strengthening the loadbearing structure. This can become necessary, for example, if live loads are increased because of changes of use or if the structural safety of a building must be restored after a fire or earthquake. Particularly columns represent important components and elements of the static system for many buildings, whose main task is bearing normal forces.The results of experimental tests on the effect of a strengthening from textile reinforced concrete at 2 m long columns, both with and without internal steel reinforcement, are described in this article. The strengthening with textile reinforced concrete was made both wrapping round completely along the full height of the columns and partly wrapping round the columns along 300 mm in the load introduction ranges. Related to the unstrengthened reference columns ultimate load increasings by up to 85% could thereby be achieved. The individual components of the load bearing properties are analysed. A simple calculation model is indicated.
Structures of Micelle‐Bound Selected Insect Neuropeptides and Analogues: Implications for Receptor Selection
Authors: Zdobinsky Tino , Scherkenbeck Jürgen , Zerbe Oliver , Antonicek Horst , Chen Heru 
Published: September 2009

AbstractNeuropeptides control essential physiological processes in insects such as water balance and muscle activity. Due to their metabolic instability and adverse physiochemical properties, insect neuropeptides are unsuited for a direct application in plant protection. As a first approximation towards the biologically active conformation, the structures of selected neuropeptides from economically important pest insects were determined by NMR spectroscopy and fluorescence measurements in a membrane‐mimicking environment. A receptor binding model is suggested for the helicokinins and discussed in connection with biological activities and membrane‐bound conformations of linear and cyclic analogues.
“Doubly Selective” Antimicrobial Polymers: How Do They Differentiate between Bacteria?
Authors: Lienkamp Karen , Kumar Kushi‐Nidhi , Som Abhigyan , Nüsslein Klaus , Tew Gregory N. 
Published: September 2009

AbstractWe have investigated how doubly selective synthetic mimics of antimicrobial peptides (SMAMPs), which can differentiate not only between bacteria and mammalian cells, but also between Gram‐negative and Gram‐positive bacteria, make the latter distinction. By dye‐leakage experiments on model vesicles and complementary experiments on bacteria, we were able to relate the Gram selectivity to structural differences of these bacteria types. We showed that the double membrane of E. coli rather than the difference in lipid composition between E. coli and S. aureus was responsible for Gram selectivity. The molecular‐weight‐dependent antimicrobial activity of the SMAMPs was shown to be a sieving effect: while the 3000 g mol−1 SMAMP was able to penetrate the peptidoglycan layer of the Gram‐positive S. aureus bacteria, the 50000 g mol−1 SMAMP got stuck and consequently did not have antimicrobial activity.
Catalytic Carbanion Reactions: Formation and Reaction of Carbanions from Ester or Amide Equivalents Using Catalytic Amounts of Bases
Authors: Kobayashi Shu , Matsubara Ryosuke 
Published: September 2009

AbstractWe describe here carbanion reactions using catalytic amounts of bases. The carbanions formed are different from conventional carbanions in which stoichiometric amounts of bases are needed for the formation. Two types of reactions using such carbanions from amide (imido) and ester equivalents are discussed.
Cyclopentadienyl Ruthenium(II) Complexes with Bridging Alkynylphosphine Ligands: Synthesis and Electrochemical Studies
Authors: Di Credico Barbara , Fabrizi de Biani Fabrizia , Gonsalvi Luca , Guerri Annalisa , Ienco Andrea , Laschi Franco , Peruzzini Maurizio , Reginato Gianna , Rossin Andrea , Zanello Piero 
Published: September 2009

AbstractThe reaction of [CpRuCl(PPh3)2] (Cp=cyclopentadienyl) and [CpRuCl(dppe)] (dppe=Ph2PCH2CH2PPh2) with bis‐ and tris‐phosphine ligands 1,4‐(Ph2PC≡C)2C6H4 (1) and 1,3,5‐(Ph2PC≡C)3C6H3 (2), prepared by Ni‐catalysed cross‐coupling reactions between terminal alkynes and diphenylchlorophosphine, has been investigated. Using metal‐directed self‐assembly methodologies, two linear bimetallic complexes, [{CpRuCl(PPh3)}2(μ‐dppab)] (3) and [{CpRu(dppe)}2(μ‐dppab)](PF6)2 (4), and the mononuclear complex [CpRuCl(PPh3)(η1‐dppab)] (6), which contains a “dangling arm” ligand, were prepared (dppab=1,4‐bis[(diphenylphosphino)ethynyl]benzene). Moreover, by using the triphosphine 1,3,5‐tris[(diphenylphosphino)ethynyl]benzene (tppab), the trimetallic [{CpRuCl(PPh3)}3(μ3‐tppab)] (5) species was synthesised, which is the first example of a chiral‐at‐ruthenium complex containing three different stereogenic centres. Besides these open‐chain complexes, the neutral cyclic species [{CpRuCl(μ‐dppab)}2] (7) was also obtained under different experimental conditions. The coordination chemistry of such systems towards supramolecular assemblies was tested by reaction of the bimetallic precursor 3 with additional equivalents of ligand 2. Two rigid macrocycles based on cis coordination of dppab to [CpRu(PPh3)] were obtained, that is, the dinuclear complex [{CpRu(PPh3)(μ‐dppab)}2](PF6)2 (8) and the tetranuclear square [{CpRu(PPh3)(μ‐dppab)}4](PF6)4 (9). The solid‐state structures of 7 and 8 have been determined by X‐ray diffraction analysis and show a different arrangement of the two parallel dppab ligands. All compounds were characterised by various methods including ESIMS, electrochemistry and by X‐band ESR spectroscopy in the case of the electrogenerated paramagnetic species.
A Stereodivergent Synthesis of All Stereoisomers of Centrolobine: Control of Selectivity by a Protecting‐Group Manipulation
Authors: Schmidt Bernd , Hölter Frank 
Published: September 2009

AbstractAll stereoisomers of the natural product centrolobine are selectively synthesized, by starting from a common precursor. Key steps are an enantioselective allylation with enantiomerically pure allylsilanes, a tandem ring‐closing metathesis–isomerization reaction, and a Heck reaction by using an arene diazonium salt. By choosing appropriate conditions for the final deprotection step, either the cis‐configured centrolobines or their epimers are selectively obtained.
ChemInform Abstract: Superparamagnetism and Other Magnetic Features in Granular Materials: A Review on Ideal and Real Systems
Authors: Knobel M. , Nunes W. C. , Socolovsky L. M. , De Biasi E. , Vargas J. M. , Denardin J. C. 
Published: October 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Density Functional Theory Study of Hydrogen Bonds of Bipyridine with 1,3,5‐Benzenetricarboxylic Acid
Authors: Li Quan , Zhao Keqing 
Published: September 2009

AbstractThe hydrogen‐bonded dimer and trimer formed between 1,3,5‐benzenetricarboxylic acid and bipyridine have been investigated using a density functional theory (DFT) method and 6‐31++G** basis set. The interaction energies are −45.783 and −89.998 kJ·mol−1 for the most stable dimer and trimer, respectively, after the basis set superposition error and zero‐point corrections. The formation of O–H...N hydrogen bonds makes O–H symmetric stretching modes in the dimer and trimer red‐shifted relative to those of the 1,3,5‐benzenetricarboxylic acid monomer. The natural bond orbit analysis shows that the inter‐molecular charge transfers are 0.60475e and 1.20225e for the dimer and trimer, respectively. Thermodynamic analysis indicates that the formation of trimer is an exothermic and spontaneous process at low and room temperature. A supramolecule can be constructed through the strong N···H–O intermolecular hydrogen bonds between bipyridine and 1,3,5‐benzenetricarboxylic acid, which is in good agreement with the experimental results.
Theoretical Studies on Electronic Structures and NMR Spectra of Oligo(4‐vinylpyridine)
Authors: Zhao Hongjian , Zhou Jia , Hu Lingjing , Teng Qiwen 
Published: September 2009

AbstractPoly(4‐vinylpyridine) was determined to possess conductivity in the experiment. In order to understand properties of the polymer, a series of 4‐vinylpyridine oligomers were designed. The structures of these oligomers were optimized using density function theory (DFT) at B3LYP/6‐31G(d) level. The energy gaps and thermal stabilities of the oligomers were decreased when the chain lengths were increased. These properties were also decreased owing to the protonation of the pyridine ring. The holes were easily injected into the oligomers in the presence of hydrochloride. The electrons were conducted in the side chain composed of the pyridine rings rather than the main chain owing to the saturation of the main chain. The 13C nuclear magnetic resonance (NMR) spectra and nucleus independent chemical shifts (NICS) of these compounds were calculated at B3LYP/6‐31G(d) level. The chemical shifts of the carbon atoms connected with the nitrogen atoms in the protonated pyridines were moved upfield in comparison with those of the pyridines. The addition of hydrochloride on the pyridine ring in the oligomers led to the increase of the aromaticities, namely the aromaticities of the oligomers were obviously improved when the pyridine rings were protonated.
Microwave‐assisted Synthesis of Pyrazolo[4,3‐f]quinolin‐7‐one Derivatives via Multi‐component Reactions
Authors: Peng Juhua , Hao Wenjuan , Wang Xiang , Tu Shujiang , Ma Ning , Zhang Ge 
Published: September 2009

AbstractA series of new pyrazolo[4,3‐f]quinolin‐7‐one derivatives were synthesized by multi‐component reactions of equimolar amount of aromatic aldehydes with 2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione and 1H‐indazol‐5‐amine in ethylene glycol without catalyst under microwave irradiation. This one‐pot protocol has the advantage of good yields, simple workup procedure and shorter reaction time.
New Preparation Methodology of Functionalized Picolines
Authors: Nie Lifei , Yong Jianping , Ba Hang , Aisa Haji Akber 
Published: September 2009

AbstractUnder the organomagnesium complex n‐Bu2CH3MgLi conditions, picoline compounds provide a new entry to a broad range of polyfunctional picoline derivatives, after reaction with various electrophiles.
γ‐Irradiation Degradation of Methamidophos
Authors: Zhao Renbang , Bao Huaying , Xia Lingyun 
Published: September 2009

AbstractThe irradiation degradation of methamidophos in aqueous solutions by 60Co‐γ rays was investigated. The effects of absorbed doses, saturated gas, and the additive of H2O2 on the degradation were also studied. The results showed that the oxidative radical, such as ·OH, played an important role in the irradiation degradation of methamidophos; while the reductive radicals, e−aq and ·H, had no contribution to the degradation. The degradation rate of methamidophos increased with the increase of the irradiation dosage. At certain irradiation dosage, methamidophos could be degraded completely. The degradation rate of methamidophos in the solution saturated with oxygen was higher than those saturated with other gases, which reached 100% when the absorbed dose was 8 kGy. H2O2 degraded methamidophos slowly when it was used alone, but could accelerate the degradation obviously when it was used with irradiation together.
Binding Interaction of Captopril with Metal Ions: A Fluorescence Quenching Study
Authors: Siddiqi K. S. , Bano Shaista , Mohd Ayaz , Khan Aslam Aftab Parwaz 
Published: September 2009

AbstractThe binding interaction of captopril (CPL) with biologically active metal ions Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+and Zn2+was investigated in an aqueous acidic medium by fluorescence spectroscopy. The experimental results showed that the metal ions quenched the intrinsic fluorescence of CPL by forming CPL‐metal complexes. It was found that static quenching was the main reason for the fluorescence quenching. The quenching constant in the case of Cu2+was highest among all quenchers, perhaps due to its high nuclear charge and small size. Quenching of CPL by metal ions follows the order Cu2+>Ni2+>Co2+>Ca2+>Zn2+>Mn2+>Mg2+. The quenching constantKsv, bimolecular quenching constantKq, binding constantKand the binding sites "n" were determined together with their thermodynamic parameters at 27 and 37°C. The positive entropy change indicated the gain in configurational entropy as a result of chelation. The process of interaction was spontaneous and mainly ΔS‐driven.
Removal of Naphthol Green B from Aqueous Solution by Calcined Layered Double Hydroxides: Adsorption Property and Mechanism Studies
Authors: Zhang Feng , Ni Zheming , Xia Shengjie , Liu Xiaoming , Wang Qiaoqiao 
Published: September 2009

AbstractThe adsorption of naphthol green B (NGB) by Mg/Al‐LDO (layered double oxides) with a Mg/Al molar ratio of 3:1 was investigated in a batch mode. Our study indicates that the maximum capacity of NGB adsorption at equilibrium is 193.4 mg and the percentage of absorption is 96.7%, with an adsorbent dose of 1.0 g/L under the following condition: 200 mg/L NGB concentration, temperature 298 K, pH 10.0 and an equilibrium time of 80 min. Langmuir and Freundlich adsorption models were used for fitting the isotherms, and the thermodynamic parameters have been calculated, which showed that the adsorption process was spontaneous and exothermic in nature. In the light of so called "memory effect", the Mg/Al‐LDO was found to recover their original layered structure after adsorption, and part of NGB ions intercalated into the interlayer of LDH (layered double hydroxides), which has been supported by XRD and FTIR. In addition, the competitive anions for adsorption and the regeneration of Mg/Al‐LDO have also been investigated.
New Azobenzene Dye Colorimetric and Ratiometric Chemosensors for Mercury(II) Ion
Authors: Guo Min , Xue Wei , Guan Mingyun , Sun Jianhua , Yin Gui 
Published: September 2009

AbstractA new series of azobenzene dyes, which possessed colorimetric and ratiometric recognition to Hg2+ based on the mechanism of internal charge transfer (ICT), was developed and characterized. The molecules involving azo and imino functional groups can coordinate with Hg2+ to result in a large blue shift from 453 to 363 nm corresponding to a notable color change from orange to pale yellow in aqueous methanol solution (H2O/CH3OH=1/4, V/V), which can be applied to naked eye detection of Hg2+. The sensitivity, selectivity and binding mode of the sensors to Hg2+ were investigated by UV‐Vis spectroscopy.
Complexes of Diquat with Dibenzo‐24‐Crown‐8
Authors: Li Shijun , Huang Feihe , Slebodnick Carla , Ashraf‐khorassani Mehdi , Gibson Harry W. 
Published: September 2009

AbstractThe complexation between dibenzo‐24‐crown‐8 (1) and diquat (2) was investigated in detail by NMR, MS and X‐ray analysis. It was found that dibenzo‐24‐crown‐8 and diquat formed a 1:1 complex 1·2 in acetone with Ka=2.0×102 L·mol−1, but, as shown by X‐ray analysis, a crystalline 2:1 host:guest inclusion complex 12·2 was isolated, in which a single molecule of diquat is enclosed in the concave cavity provided by two dibenzo‐24‐crown‐8 host molecules. Both results are different from the previously assumed stoichiometry of the complexation between dibenzo‐24‐crown‐8 and diquat. This result enriches the range of host‐guest complexes based on dibenzo‐24‐ crown‐8 and provides new opportunities for developing more complicated structures and chemosensors for diquat.
Efficient and Mild Protocol for the Synthesis of 4(3)‐Substituted 3(4)‐Nitro‐1H‐pyrroles and 3‐Substituted 4‐Methyl‐2‐tosyl‐1H‐pyrroles from Nitroolefins and Tosylmethyl Isocyanide in Ionic Liquids
Authors: Qin Jie , Zhang Ji , Wu Bo , Zheng Zhangguo , Yang Meng , Yu Xiaoqi 
Published: September 2009

Abstract A mild and convenient method for the synthesis of 4(3)‐substituted 3(4)‐nitro‐1H‐pyrroles and 3‐substituted 4‐methyl‐2‐tosyl‐1H‐pyrroles from nitroolefins and tosylmethyl isocyanide (TosMIC) in ionic liquid 1‐butyl‐3‐methylimidazolium bromide ([bmIm]Br) was developed. The reactions were performed at room temperature with KOH as base with good yields in a short time (about 2 h). Some tough conditions, such as absolutely anhydrous organic solvents, low temperature, hazardous and expensive strong base or organic base, were not needed. The yields of 4(3)‐substituted 3(4)‐nitro‐1H‐pyrroles were moderate, but excellent yields were achieved for the preparation of 3‐substituted 4‐methyl‐2‐tosyl‐1H‐pyrroles. This strategy was quite general and it worked in a broad range of nitroolefins with aromatic, aliphatic or heterocyclic substituents. The recovered ionic liquid could be reused as solvent for several times without significant decrease of reaction yields.
Chisiamols A–F, Triterpenoids from Chisocheton siamensis
Authors: Xie Bojun , Yang Shengping , Zhang Chen , Yue Jianmin 
Published: September 2009

AbstractSix new apotirucallane‐type triterpenoids, chisiamols A–F (1–6), along with two known compounds, were isolated from the twigs of Chisocheton siamensis. The structures of compounds 1–6 were established on the basis of spectroscopic and chemical methods.
DRIVE—Dispatching Requests Indirectly through Virtual Environment
Authors: Choi Hyung Won , Kwak Hukeun , Sohn Andrew , Chung Kyusik 
Published: September 2009

AbstractDispatching a large number of dynamically changing requests directly to a small number of servers exposes the disparity between the requests and the machines. In this paper, we present a novel approach that dispatches requests to servers through virtual machines, called Dispatching Requests Indirectly through Virtual Environment (DRIVE). Client requests are first dispatched to virtual machines that are subsequently dispatched to actual physical machines. This buffering of requests helps to reduce the complexity involved in dispatching a large number of requests to a small number of machines. To demonstrate the effectiveness of the DRIVE framework, we set up an experimental environment consisting of a PC cluster and four benchmark suites. With the experimental results, we demonstrate that the use of virtual machines indeed abstracts away the client requests and hence helps to improve the overall performance of a dynamically changing computing environment. Copyright © 2009 John Wiley & Sons, Ltd.
The velocity structure of the hypocenter area of 2003 M6.2 and M6.1 Dayao earthquake
Authors: Zhou Long‐Quan , Ma Hong‐Sheng , Jiang Chang‐Sheng , Zhou Jun‐Jie 
Published: September 2009

AbstractWe determine the 2003 M6.2 and M6.1 Dayao earthquake sequence location and velocity structure of the hypocenter area by the simultaneous inversion of hypocenter location and velocity structure. The distribution of the M6.2 earthquake sequences shows the shape of a ‘V’ along the depth, which corresponds to the reversing triangle shape of low‐velocity structure, namely, the after‐shocks of M6.2 are distributed along the transitional zones of high‐ and low‐velocity structure. The zones of rupture of M6.2 and M6.1 are located on the southeast side of the reversing triangle shape of low‐velocity structure. The mainshock of M6.2 ruptures downwards and the mainshock of M6.1 ruptures upwards along the transitional zones of high‐ and low‐velocity structure. The velocity structure at the depth of 6 km shows that there is the quadrant of high‐ and low‐velocity structure and the aftershocks of M6.2 and M6.1 are distributed along the northwest transitional zones of high‐ and low‐velocity structure. The value of low‐velocity structure at the southeast side of M6.2 is higher than the value of the low‐velocity structure at the northwest side, which is disadvantageous to rupture southeastward for M6.2 and is advantageous to accumulate the energy for the occurrence of M6.1. Copyright © 2009 John Wiley & Sons, Ltd.
DNA‐Based Polymers as Chiral Templates for Second‐Order Nonlinear Optical Materials
Authors: Wanapun Duangporn , Hall Victoria J. , Begue Nathan J. , Grote James G. , Simpson Garth J. 
Published: September 2009

AbstractThe unique symmetry properties of chiral systems allow the emergence of coherent second harmonic generation in polymeric materials lacking polar order. Deoxyribonucleic acid (DNA) treated with the surfactant cetyltrimethylammonium (CTMA) was drop‐cast to spontaneously form films that are active for coherent second harmonic generation (SHG). SHG images acquired as a function of incident and exigent polarization are in good agreement with theoretical predictions assuming nonpolar D∞ symmetry for the double‐stranded DNA chains. Doping the DNA films with crystal violet substantially increases the efficiency of SHG, but does not significantly alter the polarization‐dependence, suggesting that the SHG generated upon doping arises from the same chiral‐specific origin, presumably templated by the DNA. These results raise the possibility of new design strategies for organic nonlinear optical materials based on soft chiral polymers that do not require polar order.
Selectivity versus Mobility: Separation of Anode and Cathode in Microbial Bioelectrochemical Systems
Authors: Harnisch Falk , Schröder Uwe 
Published: September 2009

AbstractDuring the operation of a microbial bioelectrochemical system, charge balance must be maintained between the anode and the cathode. In an ideal scenario, the charge balance would be realized by the unhindered migration of H+ or OH−. At the same time, any kind of diffusion (crossover) between both electrode compartments should be avoided. However, as several studies have demonstrated, the experimental reality does not match this ideal picture. Crossover processes occur and H+/OH− migration only plays an inferior role in the charge‐balancing ion transfer, which results in significant losses in the performance of the microbial bioelectrochemical system. This Minireview summarizes the conflict of selectivity versus mobility and discusses principle strategies to cope with the resulting constraints, including pH‐static operation and the use of different separator materials and membrane‐free systems. Finally, we show that every setup compromises either selectivity or mobility, and no apparent ideal solution currently exists.