bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boratabenzene Anions C5B(CN)6− and C5B(CF3)6− and the Superacidic Properties of their Conjugate Acids
Authors: Kütt Agnes , Koppel Ivar , Koppel Ilmar A. , Leito Ivo 
Published: July 2008

AbstractDesigning superacids: A computational study of protonated boratabenzenes and the gas‐phase acidity of their conjugate acids is presented. Conjugate acids of boratabenzenes substituted with CN or CF3 groups (see figure) are highly acidic species; the protonated hexacyanoboratabenzene and hexakis(trifluoromethyl)boratabenzene have computational gas‐phase acidities of 250.5 and 276.8 kcal mol−1, respectively.magnified image
Growth, etching morphology and spectra of LiAlO2 crystal
Authors: Huang Taohua , Zhou Shengming , Teng Hao , Lin Hui , Wang Jun 
Published: July 2008

Abstractγ‐LiAlO2 single crystal was successfully grown by Czochralski method. The crystal quality was characterized by X‐ray rocking curve and chemical etching. The effects of air‐annealing and vapor transport equilibration (VTE) on the crystal quality, etch pits and absorption spectra of LiAlO2 were also investigated in detail. The results show that the as‐grown crystal has very high quality with the full width at half maximum (FWHM) of 17.7‐22.6 arcsec. Dislocation density in the middle part of the crystal is as low as about 3.0×103 cm–2. The VTE‐treated slice has larger FWHM value, etch pits density and absorption coefficient as compared with those of untreated and air‐annealed slices, which indicates that the crystal quality became inferior after VTE treatment. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flux growth of La‐doped lead zirconate stannate titanate antiferroelectric crystals
Authors: Wang Lin , Li Qiang , Zhang Yiling 
Published: July 2008

AbstractRelaxor antiferroelectric single crystals lead lanthanum zirconate stannate titanate (PLZST) with the composition around the morphotropic phase boundary (MPB) have been grown by flux method using 50 wt% PbO‐PbF2‐B2O3 as a flux. The obtained crystals are light yellow in color. The XRD patterns revealed that the habitual faces of the obtained crystal are (001). The crystal morphology was studied and related to a layer growth mechanism controlled by two‐dimensional growth. The chemical composition of as‐grown crystal was analyzed by inductively coupled plasma atomic emission spectrometry (ICP), indicating a slight decrease of the amount of Ti compared to the starting materials. The result was verified by the XRD patterns with the phase transformation from the co‐existence of tetragonal and rhombohedra phases to the single tetragonal phase. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth aspects of barium oxalate monohydrate single crystals in gel medium
Authors: Raj A. Moses Ezhil , Jayanthi D. Deva , Jothy V. Bena , Jayachandran M. , Sanjeeviraja C. 
Published: July 2008

AbstractSingle crystals of barium oxalate monohydrate (BaC2O4.H2O, BOM) were grown in pure form by controlled diffusion of Ba2+ using the gel technique at different temperatures. Starting from aqueous Ba2+ chloride (BaCl2) and acetic acid (C2H2O4) in gel, this method offers a low‐cost and an easiest alternative to other preparation methods for the production of barium oxalate bulky single crystals. The optimal conditions for the growth of BOM crystals in silica gel were found by investigating different growth parameters such as gel pH, gel aging and crystallization temperature. Irrespective of all such crystallization environments, growth rate of the crystals were initially less and then exhibited supersaturation effect leading to non‐linearity. Gel aging and temperature has profound effect on nucleation density that resulted less number of crystals of maximum size in the gel matrix. Perfect single crystals were grown on gels of higher pH. The macropore morphology and porosity was controlled by changing age of the gel. It has been found that temperature has a fabulous effect in controlling the nucleation density by altering the supersaturation conditions for the formation of critical nuclei. The entire growth kinetics informed that the grown crystals were derived by the one dimensional diffusion controlled process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of Ytterbium doped KGd(WO4)2 single crystal
Authors: Samuel P. , Moorthy Babu S. 
Published: July 2008

AbstractSingle crystals of Ytterbium doped KGd(WO4)2 were grown by Top Seeded Solution Growth technique using K2WO4 as flux system. The growth parameters were optimised to get optically transparent crystals. Variation in the lattice parameters were observed in comparison to the pure KGd(WO4)2 crystals. The absorption spectra recorded for the Yb:KGW confirms the material suitability for diode pumped solid state lasers. The vibrational studies carried out using spontaneous Raman spectra indicate the strong anionic vibration of the material. PL spectra show the lasing channel of the laser active ions present. Stimulated Raman scattering analysis confirms the material as an efficient Raman laser material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A theory for elastic properties of single crystals with microstructure and its application to diffusion induced segregation
Authors: Blesgen T. 
Published: July 2008

AbstractIn this article a general theory for elastically stressed single crystals in the presence of microstructure is presented and an explicit formula for the resulting non‐linear stored mechanical energy is obtained. The optimal microstructure under applied stress is characterised and the optimal laminates are identified in 2D. The analysis is based on a sharp lower estimate of the energy that relies on relaxation. The new theory is then used to extend existing models for diffusion induced segregation (DIS) in the case of (Zn,Fe)S single crystals. Numerical simulations based on finite elements are carried out and the results are compared with former computations of the homogeneous case. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and optical properties of ZnO nanorods
Authors: Lang Jihui , Yang Jinghai , Li Changsheng , Yang Lili , Han Qiang , Zhang Yongjun , Wang Dandan , Gao Ming , Liu Xiaoyan 
Published: July 2008

AbstractZnO nanorods were prepared on the silicon (100) substrates using the chemical solution deposition method (CBD) without catalyst under a low temperature (90°C). The cool water was used to dissolve the mixture of zinc nitrate hexahydrate (Zn (NO3)2·6H2O) and methenamine (C6H12N4) in order to decrease the size of ZnO nanorods. From the X‐ray diffraction (XRD) results, it can be seen that the growth orientation of the as‐prepared ZnO nanorods was (002). Scanning electron microscopy (SEM) results illustrated that the nanorods had a hexagonal wurzite structure and average diameter of about 120nm. The average diameter of nanorods prepared by the cool water process was much smaller than that by the room‐temperature (RT) water process we always used. Photoluminescence (PL) measurements were also carried out. The result showed that a blue shift in UV emission band appeared in the PL spectrum of the sample grown with cool water process, which was mainly due to the reduction of tensile strain when the diameter of the ZnO nanorods decreased. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization and crystal structure of a novel 3‐D copper(II) polymer with bent N‐containing ligand
Authors: Wang Fumin 
Published: July 2008

AbstractAn exploration of the mixed‐ligand system under hydrothermal condition, has led to the isolation of a 3‐D novel framework {[Cu2(mp)L2)(H2O)2]·6H2O}n (1) (mp = benzene‐1,2,4,5‐ tetracarboxylate tetraanion, L = 4‐(5‐(pyridin‐4‐yl)‐1,3,4‐thiadiazol‐2yl)pyridine). Single‐crystal X‐ray analyses reveal that it crystallizes in the triclinic space group P‐1, a = 8.807(4) Å, b =11.139(6) Å, c = 11.291(5) Å, α=75.337(7), β = 73.584(5), γ= 66.795(5)°. The CuII ions are linked into an extended 2‐D grid net via mp molecules. Further these layers are united together through the bridging L to form a 3‐D structure, which exhibits a new 4‐connected topological network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization and crystal structure of a novel 2D Cu(I) complex with flexible ligand
Authors: Liu Jianqiang , Wang Yaoyu , Zhang Weihong , Jin Juncheng , Zhang Mei , Shi Qizhen 
Published: July 2008

AbstractAn exploration of the Cu(I)‐L system under hydrothermal conditions, has led to the isolation of a novel framework [Cu(I)(L)]n (1) (L = bis(3,3‐dimethyl‐4,4‐dihydro‐1H‐pyrazol‐4‐yl)methane). Single‐crystal X‐ray analysis reveals that it crystallizes in the monoclinic, space group C2/c, a = 19.781(4) Å, b =11.026(3) Å, c = 16.339(4) Å, β = 127.186(3)°. The Cu ions are linked into an extended rainbow‐like chain via L molecules. Further, these adjacent chains are united together through hydrogen‐bonded interaction to a 2D layer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Real time monitoring of BMP Smads transcriptional activity during mouse development
Authors: Monteiro Rui M. , de Sousa Lopes Susana M. Chuva , Bialecka Monika , de Boer Sophie , Zwijsen An , Mummery Christine L. 
Published: July 2008

AbstractBone morphogenetic protein (BMP) signaling is a key pathway in the patterning and development of organisms as diverse as fruit fly and humans. However, the determination of net BMP signaling, paramount to understanding organogenesis, is limited to the analysis of fixed material. We generated a transgenic mouse that reports the transcriptional response of BMP Smad activation by coupling a well established BMP response element (BRE), isolated from the Id1 promoter, to green fluorescent protein (BRE:gfp). We monitored BMP Smad transcriptional activity in fresh and fixed BRE:gfp embryos. GFP expression was observed where expected on the basis of known signaling sites, but also in specific cell populations in which BMP signaling had been implicated but not directly demonstrated. Deletion of Smad5 reduced GFP in vivo as expected. The BRE:gfp transgenic mice are a novel tool, which will facilitate the identification of specific BMP Smad responsive cell types and allow BMP Smad signaling to be monitored in real time, supporting studies in development and disease. genesis 46:335–346, 2008. © 2008 Wiley‐Liss, Inc.
Development of a gene‐trap vector with a highly sensitive fluorescent protein reporter system for expression profiling
Authors: Tanaka Tetsuya S. , Davey Ryan E. , Lan Qing , Zandstra Peter W. , Stanford William L. 
Published: July 2008

AbstractCombining high‐content screening (HCS) with random gene‐trap mutagenesis could be a powerful tool to investigate transcriptional networks, cell signaling, chemical genetics, and developmental processes. However, a critical limitation has been poor quantification of reporter expression per cell. To overcome this hurdle, we generated a variety of Gtx‐based expression cassettes and re‐evaluated translational enhancement of arrayed Gtx segments in tandem by HCS. We then modified the cassette into a new polyA trap vector, which consists of a variant of yellow fluorescent protein, Venus, in combination with the Gtx segments. Expression of Venus was detected in about 60% of trapped genes assayed in embryonic stem cell (ESC) cultures, comparable to expression screening of LacZ‐based vectors. Furthermore, tetraploid aggregations using a clone encoding a gene‐trap insertion into Twist2 demonstrated identical spatiotemporal expression between Venus and Twist2. This highly sensitive reporter system is amenable to high‐throughput expression‐based real‐time HCS including single cell analyses. genesis 46:347–356, 2008. © 2008 Wiley‐Liss, Inc.
Deletion of GAD67 in dopamine receptor‐1 expressing cells causes specific motor deficits
Authors: Heusner Carrie L. , Beutler Lisa R. , Houser Carolyn R. , Palmiter Richard D. 
Published: July 2008

AbstractThe medium spiny neurons (MSNs), which comprise the direct and indirect output pathways from the striatum, use γ‐aminobutyric acid (GABA) as their major fact‐acting neurotransmitter. We generated mice carrying a conditional allele of the Gad1 gene, which encodes GAD67, one of the two enzymes responsible for GABA biosynthesis, and bred them to mice expressing Cre recombinase at the dopamine D1 receptor locus (Drd1a) to selectively reduce GABA synthesis in the direct output pathway from the striatum. We show that these mice are deficient in some types of motor skills, but normal for others, suggesting a differential role for GABA release from D1 receptor‐containing neurons. genesis 46:357–367, 2008. © 2008 Wiley‐Liss, Inc.
Synthesis of Manganese Oxide Hollow Urchins with a Reactive Template of Carbon Spheres
Authors: Wang Nan , Gao Yu , Gong Jian , Ma Xinyan , Zhang Xiaoli , Guo Yihang , Qu Lunyu 
Published: July 2008

AbstractIn this paper, a novel route to synthesize manganese oxide (MnO2) hollow urchins by a reactive template of carbon spheres is described. The formation process of the MnO2 hollow urchins and the mechanism for the removal of the carbon spheres are suggested. The results of scanning electron microscopy and transmission electron microscopy indicate that MnO2 shows a hollow‐urchin structure with an average diameter of 1.5 μm and with cavities that are about 250–500 nm in diameter. The X‐ray diffraction pattern indicates that the as‐prepared hollow urchins are γ‐MnO2. It has a highBrunauer–Emmett–Teller surface area of 110 m2 g–1 and a mesoporous structure. In addition, the magnetic properties of the γ‐MnO2 hollow urchins are investigated. This method opens a way to obtain different morphologies of metal oxides by changing the morphologies of the reactive carbon template. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Crystal Packing in Di‐(μ‐OH)‐ortho‐palladated Complexes – A DFT Insight into the Molecular Structure and Solid‐State Interactions
Authors: Pérez Jose , Espinosa Arturo , Galiana Jose M. , Pérez Eduardo , Serrano Jose L. , Cabeza Aurelio , Aranda Miguel A. G. 
Published: July 2008

AbstractThe crystal structures of [Pd(μ‐OH)(C∧N)]2[C∧N = phpy = 2‐(2‐pyridyl)phenyl (1), C∧N = bzq = 7,8‐benzoquinolin‐10‐yl (2)] have been elucidated by ab initio X‐ray powder diffraction methodology with monochromatic Cu‐Kα1radiation. The crystal structures have been refined by the Rietveld method. Both complexes exhibit a planar conformation in the solid state (which is the most frequent for this type of compounds as found in the Cambridge Structural Database). In compound1, three molecules are stacked in an overlappingparallel orientation. DFT calculations reveal that hydrogen bonds and Pd···Pd interactions are the reasons for the stability of this “trimer”. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Ferrocene‐Based Small Molecules for Multichannel Molecular Recognition of Cations and Anions
Authors: Molina Pedro , Tárraga Alberto , Caballero Antonio 
Published: July 2008

AbstractThis manuscript provides a summary of the relatively large body of research on the preparation and sensing properties of ferrocenes containing nitrogen functionalities, which have been mainly developed by our research group. After a general overview of the topic, selected recent advances in this field are described. In particular, new acyclic and cyclic structural motifs, in which the ferrocene unit is linked by unsaturated aza bridges (azadiene, azine, urea, guanidine, azaheterocycles) to a chromogenic or fluorescent signalling unit. Attention is drawn to the electrochemical and optical properties of these aza‐substituted ferrocene derivatives as well as their use in multichannel molecular recognition processes towards metal cations and anions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Amberlite IRA900F as a Solid Fluoride Source for a Variety of Organic Transformations under Solvent‐Free Conditions
Authors: Fringuelli Francesco , Lanari Daniela , Pizzo Ferdinando , Vaccaro Luigi 
Published: July 2008

AbstractWe have reported that Amberlite IRA900F (Amb‐F) is an efficient metal‐free catalyst for the activation of Si–N and Si–O bonds and a mild base in a variety of organic transformations under solvent‐free conditions, such as the addition of TMSN3 to (E)‐2‐aryl‐1‐cyano‐1‐nitroethenes, nitriles, α,β‐unsaturated acids and their esters, and the addition of dimethylsilylketene acetal and ethyl nitroacetate to β‐nitrostyrenes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Mechanisms of Brønsted Acid Catalyzed Additions of Phenols and Protected Amines to Olefins: A DFT Study
Authors: Li Xin , Ye Siyu , He Chuan , Yu Zhi‐Xiang 
Published: July 2008

AbstractDFT calculations at the B3LYP/6‐31G(d) level were performed to understand the mechanism of the recentlydeveloped trifluoromethanesulfonic acid (TfOH) catalyzed intermolecular additions of phenols and protected amines to simple olefins. A novel mechanism involving a concerted, eight‐membered‐ring transition structure for the addition of the alcohol/amine to the alkene with TfOH as a catalyst was located. In the addition transition structure, the alkene substrate is protonated and has significant carbocation character. Calculations to rationalize the relative reactivities of the alcohols and amines, together with the regioselectivity of amide addition to the diene, were also conducted. Factors affecting isomerization of the alkene substrates in the alcohol addition process are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Multicomponent Domino Reaction Promoted by Mg(ClO4)2: Highly Efficient Access to Functionalized 1,4‐Dihydropyridines
Authors: Bartoli Giuseppe , Bosco Marcella , Galzerano Patrizia , Giri Roberto , Mazzanti Andrea , Melchiorre Paolo , Sambri Letizia 
Published: July 2008

AbstractAn efficient, one‐pot multicomponent synthetic protocol toward substituted 1,4‐dihydropyridines from aromatic amines, β‐keto derivatives, and ethyl propiolate mediated by Mg(ClO4)2 is described. When ortho‐ or meta‐substituted arylamines are used, two conformational isomers are generated. An NMR spectroscopic study of the energy barrier involved in the interconversion of the isomers is reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Evaluation of an Intramolecular Approach for the Synthesis of the Elusive C58N2 Heterofullerene Family
Authors: von Delius Max , Hauke Frank , Hirsch Andreas 
Published: July 2008

AbstractA new approach towards the synthesis of the elusive heterofullerene C58N2 is presented. The synthetic strategy is based on the intramolecular 1,3‐dipolar cycloaddition of a spacer‐linked azide to a monoazaheterofullerene (C59N) core. Since this cycloaddition can theoretically result in 16 different isomeric products, the design of the spacer moiety was based on extensive molecular modelling. Two fundamental synthetic routes towards suitably functionalized C59N derivatives were designed and carried out. Subsequent one‐pot experiments, each making use of the same conditions as had previously been employed for the introduction of the first nitrogen atom into the fullerene framework, were performed. Immediate analysis by FAB mass spectrometry indicated that up to 20 % of the submitted material indeed gave C58N2 species as fragmentation products. This result not only represents the first strategic synthesis of a C58N2 derivative, but also holds great promise for further efforts directed towards the preparative isolation of a member of the diaza[60]fullerene family. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Alkynyl Halides in Ruthenium(II)‐Catalyzed [2+2] Cycloadditions of Bicyclic Alkenes
Authors: Allen Anna , Villeneuve Karine , Cockburn Neil , Fatila Elisabeth , Riddell Nicole , Tam William 
Published: July 2008

AbstractRu‐catalyzed [2+2] cycloadditions between bicyclic alkenes and alkynyl halides were found to occur in moderate to good yields. The presence of the halide moiety greatly enhances the reactivity of the alkyne component in the cycloaddition and can be transformed into a variety of products that are difficult or impossible to obtain by direct cycloaddition. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Spatial dependence in the tails of air pollutant distributions: alternatives to the spatial correlogram
Authors: Arbia G. , Copetti M. , Lafratta G. 
Published: July 2008

AbstractThe study of the pollutants needs a better understanding of their extreme behaviours which could potentially cause adverse health effects. When analysing spatial dependence of the pollutant, the dependogram proposed by Arbia and Lafratta is preferred to the traditional correlogram used in the spatial statistics literature because it captures nonlinear relationships in the tails of the joint distributions and helps in detecting a pattern of spatial regularities. In this paper, we present a new method to estimate the spatial dependogram that uses univariate and bivariate threshold models. The method is applied to a set of hourly NO2data collected by seven monitoring stations in the city of Rome (Italy) during the years 2000 and 2001. Copyright © 2008 John Wiley & Sons, Ltd.
Large‐scale seismic tests of tall concrete bridge columns with precast segmental construction
Authors: Wang Jui‐Chen , Ou Yu‐Chen , Chang Kuo‐Chun , Lee George C. 
Published: July 2008

AbstractPast experimental studies have shown that existing precast segmental concrete bridge columns possess unsatisfactory hysteretic energy dissipation capacity, which is an undesirable feature for applications in seismic regions. In this research, we propose new methods of precast segment construction for tall concrete bridge columns to enhance the columns' hysteretic energy dissipation capacity and lateral strength. This is accomplished by adding bonded mild steel reinforcing bars across the segment joints, strengthening the joint at the base of the column and increasing the height of the base segment (hinge segment). Four large‐scale column specimens were fabricated and tested with lateral cyclic loading in the laboratory. Each specimen consisted of a foundation and 9 or 10 precast column segments. Test results of specimens with the proposed design concepts showed ductile behavior and satisfactory hysteretic energy dissipation capacity. In addition to the experimental study, an analytical study using the finite element method was conducted to understand the bond conditions, strain contours and deformation patterns of the specimens tested. Good agreement was found between the experimental observations and the results of the calibrated analytical study. Copyright © 2008 John Wiley & Sons, Ltd.
Cyclic tests on a hybrid coupled wall utilizing a rocking mechanism
Authors: Hitaka Toko , Sakino Kenji 
Published: July 2008

AbstractA new type of hybrid coupled wall system, consisting of rolled steel coupling beams, reinforced concrete (RC) wall piers, and concrete‐filled tube (CFT) short columns, is introduced. In this new system, the bases of the wall piers are connected to the base beams only through CFT short columns, unlike conventional coupled walls. Yield occurs in the coupling beams and the short columns; hence, in the RC wall piers, only minimum cracking appears. A total of four subassembly specimens, designed to fail in various collapse mechanisms, were cyclically loaded under constant axial force. A benchmark specimen showed ductile behavior with large energy dissipation until fracture occurred in the coupling beam. In the specimen designed to fail in shear in its CFT, substantial axial shortening was observed, but the overall behavior was ductile. Behavior of specimens with small amounts of section steel in the wall panel fringe, or with thin wall panels, also showed ductile behavior, but the strength and energy dissipation were significantly smaller than other two specimens. An analytical model was proposed for a frame analysis program using fiber elements to simulate elastic–plastic behavior of the system. Design methods to prevent shear failure of CFT and RC panels are suggested using the analytical and test results. Copyright © 2008 John Wiley & Sons, Ltd.