bluuebunny/crossref_metadata_2025_split huggingface dataset:
Half‐Sandwich o‐N,N‐Dimethylaminobenzyl Complexes over the Full Size Range of Group 3 and Lanthanide Metals. Synthesis, Structural Characterization, and Catalysis of Phosphine PH Bond Addition to Carbodiimides
Authors: Zhang Wen‐Xiong , Nishiura Masayoshi , Mashiko Tomohiro , Hou Zhaomin 
Published: December 2007

AbstractThe acid‐base reactions between the rare‐earth metal (Ln) tris(ortho‐N,N‐dimethylaminobenzyl) complexes [Ln(CH2C6H4NMe2‐o)3] with one equivalent of the silylene‐linked cyclopentadiene‐amine ligand (C5Me4H)SiMe2NH(C6H2Me3‐2,4,6) afforded the corresponding half‐sandwich aminobenzyl complexes [{Me2Si(C5Me4)(NC6H2Me3‐2,4,6)}Ln(CH2C6H4NMe2‐o)(thf)] (2‐Ln) (Ln=Y, La, Pr, Nd, Sm, Gd, Lu) in 60–87 % isolated yields. The one‐pot reaction between ScCl3 and [Me2Si(C5Me4)(NC6H2Me3‐2,4,6)]Li2 followed by reaction with LiCH2C6H4NMe2‐o in THF gave the scandium analogue [{Me2Si(C5Me4)(NC6H2Me3‐2,4,6)}Sc(CH2C6H4NMe2‐o)] (2‐Sc) in 67 % isolated yield. 2‐Sc could not be prepared by the acid‐base reaction between [Sc(CH2C6H4NMe2‐o)3] and (C5Me4H)SiMe2NH(C6H2Me3‐2,4,6). These half‐sandwich rare‐earth metal aminobenzyl complexes can serve as efficient catalyst precursors for the catalytic addition of various phosphine PH bonds to carbodiimides to form a series of phosphaguanidine derivatives with excellent tolerability to aromatic carbon‐halogen bonds. A significant increase in the catalytic activity was observed, as a result of an increase in the metal size with a general trend of La>Pr, Nd>Sm>Gd>Lu>Sc. The reaction of 2‐La with 1 equiv of Ph2PH yielded the corresponding phosphide complex [{Me2Si(C5Me4)(NC6H2Me3‐2,4,6)}La(PPh2)(thf)2] (4), which, on recrystallization from benzene, gave the dimeric analogue [{Me2Si(C5Me4)(NC6H2Me3‐2,4,6)}La(PPh2)]2 (5). Addition of 4 or 5 to iPrNCNiPr in THF yielded the phosphaguanidinate complex [{Me2Si(C5Me4)(NC6H2Me3‐2,4,6)}La{iPrNC(PPh2)NiPr}(thf)] (6), which, on recrystallization from ether, afforded the ether‐coordinated structurally characterizable analogue [{Me2Si(C5Me4)(NC6H2Me3‐2,4,6)}La{iPrNC(PPh2)NiPr}(OEt2)] (7). The reaction of 6 or 7 with Ph2PH in THF yielded 4 and the phosphaguanidine iPrNC(PPh2)NHiPr (3 a). These results suggest that the catalytic formation of a phosphaguanidine compound proceeds through the nucleophilic addition of a phosphide species, which is formed by the acid‐base reaction between a rare‐earth metal o‐dimethylaminobenzyl bond and a phosphine PH bond, to a carbodiimide, followed by the protonolysis of the resultant phosphaguanidinate species by a phosphine PH bond. Almost all of the rare earth complexes reported this paper were structurally characterized by X‐ray diffraction studies.
Highly Enantio‐ and s‐trans CC Bond Selective Catalytic Hydrogenation of Cyclic Enones: Alternative Synthesis of (−)‐Menthol
Authors: Ohshima Takashi , Tadaoka Hiroshi , Hori Kiyoto , Sayo Noboru , Mashima Kazushi 
Published: December 2007

AbstractA highly enantioselective catalytic hydrogenation of cyclic enones was achieved by using the combination of a cationic RhI complex, (S)‐5,5′‐bis{di(3,5‐di‐tert‐butyl‐4‐methoxyphenylphosphino)}‐4,4′‐bi‐1,3‐benzodioxole (DTBM‐SEGPHOS), and (CH2CH2PPh3Br)2. The presence of an s‐cis CC bond isopropylidene moiety on the cyclic enone influenced the enantioselectivity of the hydrogenation. Thus, the hydrogenation of 3‐alkyl‐6‐isopropylidene‐2‐cyclohexen‐1‐one, which contains both s‐cis and s‐trans enones, proceeded in excellent enantioselectivity (up to 98 % ee). To obtain high enantio‐ and s‐trans selectivities, the addition of a halogen source to the cationic Rh complex was the essential step. With the key step of the s‐trans selective asymmetric hydrogenation of piperitenone, we demonstrated a new synthetic method for optically pure (−)‐menthol via three atom‐economical hydrogenations. Moreover, we found that the complete s‐trans and s‐cis CC bond selective reactions were also realized by the proper choice of both the chiral ligands and halides.
Conjugate Addition of Indoles to α,β‐Unsaturated Ketones (Chalcones) Catalyzed by KHSO4 under Ultrasonic Conditions
Authors: ZENG Xiao‐Fei , JI Shun‐Jun , SHEN Shu‐Su 
Published: December 2007

AbstractConjugate addition of indoles to a variety of α,β‐unsaturated ketones (chalcones) mediated by a catalytic amount of KHSO4 at room temperature under ultrasonic conditions to afford the corresponding Michael adducts in good to excellent yields was reported.
Synthesis of a Novel Carbon Based Acid Catalyst and Its Catalytic Activity for the Acetalization and Ketalization
Authors: LIANG Xue‐Zheng , GAO Shan , CHEN Wen‐Ping , WANG Wen‐Juan , YANG Jian‐Guo 
Published: December 2007

AbstractA novel carbon based strong solid acid catalyst has been synthesized successfully. The catalytic activity for acetalization and ketalization was investigated. The results showed that the novel catalyst was very efficient with the average yield over 92%. The novel heterogeneous catalyst also has the advantages of high activity, wide applicability even to the preparation of 7 membered ring acetals and ketals, strikingly simple workup procedure, non‐pollution and reusability, which will contribute to the green process greatly.
Fast Determination of Clenbuterol and Salbutamol in Feed and Meat Products Based on Miniaturized Capillary Electrophoresis with Amperometric Detection
Authors: CHU Qing‐Cui , GENG Cheng‐Huai , ZHOU Hui , YE Jian‐Nong 
Published: December 2007

AbstractThe fast separation capability of a novel miniaturized capillary electrophoresis with an amperometric detection (μCE‐AD) system was demonstrated by determining clenbuterol and salbutamol in real samples. The effects of several factors such as the acidity and concentration of the running buffer, the separation voltage, the applied potential and the injection time on CE‐AD were examined and optimized. Under the optimum conditions, the two β‐agonists could be baseline separated within 60 s at a separation voltage of 2 kV in a 90 mmol/L H3BO3‐Na2B4O7 running buffer (pH 7.4), which was not interfered by ascorbic acid and uric acid. Highly linear response was obtained for above compounds over three orders of magnitude with detection limits ranging from 1.20×10−7 to 6.50×10−8 mol/L (S/N=3). This method was successfully used in the analysis of feed and meat products with relatively simple extraction procedures.
Esterification of Carboxylic Acids and Diacids by Trialkyl Borate under Solvent and Catalyst‐Free Conditions
Authors: MANSOORI Yagoub , TATAROGLU SEYIDOV Firdovsi , BOHLOOLI Shahrbanoo , ZAMANLOO Mohammad Reza , IMANZADEH Gholam Hassan 
Published: December 2007

AbstractEsterification or transesterification reactions are usually carried out in the presence of homogeneous or heterogeneous catalysts. However, recently a new method was reported for the esterification of carboxylic acids by tributyl borate under solvent‐ and catalyst‐free conditions. In order to show the synthetic ability of trialkyl borate esters in the esterification reactions, here, the esterification of other carboxylic acids and diacids by tributyl‐, triisoamyl‐, and tribenzyl borate under the same conditions were reported. Some of the prepared ester and diester products have found wide applications as plasticizers and synthetic ester base lubricants. The esterification reactions have been cleanly carried out in the absence of any solvent under catalyst‐free conditions. The maximum rate belongs to isoamyl trichloroacetate (VIb) which reached about 76% within about 6.5 h. On the basis of obtained findings, it seems that electron withdrawing groups on carboxylic acid facilitate the esterification reaction.
Description of the Structure and Properties of Atactic Polystyrene Melt Using Integral Equation Theory
Authors: ZHAO Lei , LI Yi‐Gui , ZHONG Chong‐Li 
Published: December 2007

AbstractThe polymer reference interaction site model (PRISM) integral equation theory was used to describe the structure and thermodynamic properties of atactic polystyrene (aPS) melt, in which the monomer of aPS is represented with an eight‐site model to characterize its microstructure. The intramolecular structure factors needed in the PRISM calculations were obtained from single chain MD simulations. The calculated results indicate that the results by the integral equation method agrees well with experiments, and can reflect the fine microscopic structure of real aPS melt. This work shows that the PRISM theory is a powerful tool for investigating the structure and properties of complex polymers.
A New matching strategy: Trial of the principal component coordinates
Authors: Agahian Farnaz , Amirshahi Seyed Hossein 
Published: December 2007

AbstractA new matching strategy based on the equalization of the first three principal component coordinates of sample and target in a 3D eigenvector space is stated. Two series of databases including 1269 specimens of Munsell Color Book and a virtual sample population of textile materials were selected. Their first three basis functions were extracted and considered as axes of eigenvector space. The principal component coordinates of two different collections of textile samples were determined in these spaces and considered as matching criteria. The performance of the proposed algorithm is evaluated by the color difference values under different light sources as well as the root mean square differences of reflectance curves. Results indicate some types of improvements in comparison with previous algorithms in terms of spectral as well as colorimetric accuracy. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 10–18, 2008
Camera color analysis gamut
Authors: Hunt Robert W. G. , Pointer Michael R. 
Published: December 2007

AbstractMichael Brill has opened a valuable discussion about camera gamuts and Roy Berns has questioned the use of the word “gamut” in that proposal. We would like to stress the importance of associating a gamut with an imaging output device and would thus question the use of the concept proposed for assessing the capabilities of an input device. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 81–82, 2008
Try camera gamut again: Not for size, but for camera and profile evaluation
Authors: Brill Michael H. 
Published: December 2007

AbstractHunt and Pointer call into question the utility of the camera color gamut (at least by my definition). Such doubt may be partly due to the connection of gamut with a size metric. Quite apart from gamut size, the sets that define my gamut definition are essential to the evaluation of digital cameras in conjunction with their profiles. The output‐device gamut; emphasized by Hunt and Pointer is also important, but appears at another stage of color management. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 82–83, 2008
Particle‐in‐Cell Simulation of Stationary Plasma Thruster
Authors: Taccogna F. , Longo S. , Capitelli M. , Schneider R. 
Published: December 2007

AbstractA very good example for the application of PIC techniques for detailed studies of low‐temperature plasmas is the Hall thrusters. Here, a variety of models with different complexities are needed to get better insight into the physics of these systems. Particular emphasis has been spent for the geometrical scaling, for the simulation of the plasma‐wall interaction inside the acceleration channel and for ion‐neutral collision into the plume emitted from the thruster. Results show the axial acceleration mechanism, the secondary electron emission instability, the azimuthal fluctuations into the channel and the ion backflow and electron trapping in the plume. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electric Microfield Distributions in Dense One‐ and Two‐Component Plasmas
Authors: Sadykova S. , Ebeling W. 
Published: December 2007

AbstractThe electric microfield distributions have been calculated using an integral‐equation method for one‐component plasmas proposed by Iglesias [1] and the coupling‐parameter integration technique for two‐component plasmas proposed by Ortner et al. [2]. Electric microfield distributions are studied in the frame of the Kelbg pseudopotential model, taking into account quantum‐mechanical effects (diffraction, quantum symmetry effects) and screening effects. The screened pseudopotential is represented in a numerically approximated form. The results are compared with simulation results obtained by other authors. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic Field
Authors: Stoiljković M. M. , Pavlović M. , Savović J. , Kuzmanović M. 
Published: December 2007

AbstractDirect current (dc) arc plasma with continuous aerosol supply was coupled with an external oscillatingmagnetic field of a few tens of mT and a frequency of up to 1 kHz. Such configuration was used to alter the plasma‐related radiative properties. The magnetic field was oriented perpendicularly to the electric field in the plasma and forced the arc column to oscillate as a whole with respect to the surrounding atmosphere. The magnitude of the appliedmagnetic.eld controls the amplitude of the oscillatory motion. Several parameters that can contribute to the radiative properties of the plasma were investigated (arc current, composition of aerosol introduced into the plasma, amplitude and frequency of the magnetic field applied). Spectral emission from different zones of the plasma column was measured by optical emission spectroscopy (OES). In comparison to steady‐state plasma, the applied magnetic field induces an intensity enhancement of emission of the most analytes considered. The intensity enhancement is strongly affected by the amplitude and frequency of plasma column oscillations, i.e. by plasma column velocity. Also, intensity enhancement depends on the plasma zone observed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Cathode and Anode Voltage on an Ion Sheath Thickness in a Magnetically Confined Diffusion Plasma
Authors: Mishra M. Kr. , Phukan A. 
Published: December 2007

AbstractThis article reports about the ion sheath thickness variation occurring in front of a negatively biased plate immersed in the target plasma region of a double plasma device. The target plasma is produced due to the local ionization of neutral gas by the high energetic electrons coming from the source region (main discharge region). It is observed that for an increase in cathode voltage (filament bias voltage) in the source region, the ion flux into the plate increases. As a result, the sheath at the plate contracts. Again, for an increase in source anode voltage (magnetic cage bias), the ion flux to the plate decreases. As a result, the sheath expands at the plate. The ion sheath formed at the separation grid of the device is found to expand for an increase in cathode voltage and it contracts for an increase in the anode voltage of the main discharge region. One important observation is that the applied anode bias can control the Bohm speed of the ions towards the separation grid. Furthermore, it is observed that the ion current collected by the separation grid is independent of changes in plasma density in the diffusion region but is highly dependent on the source plasma parameters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anomalous Diffusion in a Linear Plasma Generator
Authors: Waldmann O. , Meyer H. , Fussmann G. 
Published: December 2007

AbstractPlasma production and particle transport of the magnetized plasma in the linear device PSI‐2 are investigated by analyzing the radial density and electron temperature pro.les obtained from Langmuir probe measurements. Additional information on the atomic (H) and proton temperatures is obtained from high resolution Doppler spectroscopy. The density profiles are found to be hollow, but do extend radially far beyond the visible rim with an exponential decay length of 3 cm. They can be explained by parallel and perpendicular diffusion in combination with a cylindrical source extending along the magnetic field all over the device. A large perpendicular diffusion coefficient in the range of 5 m2/s is inferred from the experimental results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variations of Plasma Parameters and Sheath Thickness Due to the Extraction of Ion and Electron Flux in a Double Plasma Device
Authors: Mishra M. K. , Phukan A. , Chakraborty M. 
Published: December 2007

AbstractInfluence of charged particle extraction on plasma parameters and on ion sheath has been investigated in a double plasma device. When ions are extracted from the plasma, the plasma density as well as the positive ion flux into the sheath increases. As a result a sheath contraction takes place. Again, in case of electron extraction, it is found that the plasma density as well as the positive ion flux into the sheath decreases. As a result a sheath expansion takes place. Furthermore, it is observed that the floating potential of a plate can be controlled by extracting charged particles from the plasma. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Influence of a Longitudinal Magnetic Fields on a Non‐Uniform Positive Column
Authors: Akbar D. , Bilikmen S. 
Published: December 2007

AbstractThe variations of plasma parameters of a dc discharge in a non‐uniform magnetized plasma were measured using fast floating double Langmuir probes. A solenoid is used to produce a uniform magnetic field parallel to the discharge axis. The axial changes of the plasma parameters are presented in the range of longitudinal magnetic fields 200 to 600 Gauss at the pressure range 0.3 to 2.1 Torr and discharge currents 5 and 15 mA in argon gas. The experimental results indicate that, as a consequence of the axial magnetic.eld and the variations in the discharge tube radii, the plasma parameters at small radius exhibit obvious changes in their distributions along the axis compared to the situation of unmagnetized plasma. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Increased TLR responses in dendritic cells lacking the ITAM‐containing adapters DAP12 and FcRγ
Authors: Chu Ching‐Liang , Yu Yen‐Ling , Shen Kuan‐Yin , Lowell Clifford A. , Lanier Lewis L. , Hamerman Jessica A. 
Published: December 2007

AbstractThe inhibitory effect of DAP12 on macrophages has been revealed by examining myeloid cells from DAP12‐deficient mice. In this report, we demonstrate that both DAP12 and the FcϵRIγ‐chain (FcRγ) are required for negative regulation of TLR responses in bone marrow‐derived dendritic cells (DC). Loss of both DAP12 and FcRγ enhanced the pro‐inflammatory cytokine production and maturation of DC after TLR stimulation, resulting in a greater percentage of DC that produced IL‐12 p40, TNF, and IL‐6, and expressed high levels of MHC class II, CD80, and CD86. Whereas DC lacking only DAP12 showed some increased TLR responses, those lacking only FcRγ had a greater enhancement of maturation and cytokine production, though to a lesser extent than DC lacking both DAP12 and FcRγ. Additionally, antigen‐specific T cell proliferation was enhanced by DAP12–/–FcRγ–/– DC relative to wild‐type DC after maturation. Similar to DAP12–/–FcRγ–/– DC, Syk‐deficient DC also had increased inflammatory cytokine production, maturation, and antigen presentation. These results confirm the inhibitory effect of immunoreceptor tyrosine‐based activation motif (ITAM) signaling in myeloid cells and show that DC and macrophages differ in their dependence on the ITAM‐containing adapters DAP12 and FcRγ for negative regulation of TLR signaling.
Long‐term maternal imprinting of the specific B cell repertoire by maternal antibodies
Authors: Fink Katja , Zellweger Raphael , Weber Jacqueline , Manjarrez‐Orduno Nataly , Holdener Martin , Senn Beatrice M. , Hengartner Hans , Zinkernagel Rolf M. , Macpherson Andrew J. 
Published: December 2007

AbstractMaternal antibodies protect newborns whilst they are immunologically immature. This study shows that maternal antibodies can also shape the B cell repertoire of the offspring long after the maternal antibodies themselves become undetectable. VHDJH gene‐targeted (VI10) mice expressing a heavy chain specific for vesicular stomatitis virus (VSV) produce a 20‐fold increased spontaneous titer of VSV‐neutralizing antibodies. When transferred from mother to offspring, these antibodies prevented accumulation of Ag‐specific transitional type 2 and marginal zone B cells with an activated phenotype and favored selection to the B cell follicles. This effect was B cell‐intrinsic and lasted up to adulthood. The pups nursed by mothers producing specific antibodies developed higher endogenous antibody titers of this specificity which perpetuated the effects of specific B cell selection into the mature follicular compartment, presumably by blocking auto‐Ag‐dependent development of transitional type 2 B cells in the spleen. This repertoire change was functional, as following infection of adult mice with VSV, those pups that had received specific maternal antibodies as neonates had increased pre‐immune titers and mounted strong early IgG neutralizing antibodies.
Electrochemical Synthesis of ZnO Nanoparticles
Authors: Starowicz Maria , Stypuła Barbara 
Published: December 2007

AbstractThe anodic behaviour of zinc was investigated in ethanol solution containing LiCl and water. Zinc was polarised by using cyclic voltammetry and chronoamperometry techniques. During the course of the dissolution of zinc, a colloidal suspension of ZnO nanoparticles was obtained in 0.1 M LiCl/ethanol solutions that contain H2O. The suspension is formed only if water is present, and the rate of the process depends on the water content. Moreover, the concentration of H2O directly influences the size of the particles. However, there is evidence of a Zn5(OH)8Cl2·H2O admixture, which is detectable in the precipitates obtained with a high concentration of water. Polarisation of zinc under the given conditions is a very simple method of producing ZnO nanoparticles. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Interesterification of sesame oil and a fully hydrogenated fat using an immobilized lipase catalyst in both batch and continuous‐flow processes
Authors: Lopez‐Hernandez Arnoldo , Otero Cristina , Hernández‐Martín Estela , Garcia Hugo S. , Hill Charles G. 
Published: December 2007

AbstractLipase‐mediated interesterification of sesame oil and a fully hydrogenated soybean oil was studied at 70 °C in both a batch reactor (BR) and a continuous‐flow packed‐bed reactor (PBR) using four different initial weight ratios of substrates (90 : 10, 80 : 20, 70 : 30 and 60 : 40) with Lipozyme TL IM (Thermomyces lanuginosa) as the biocatalyst. Reaction rates were determined by following the dependence of the profile of the product triacylglycerols (TAG) on the reaction time (BR) or the space time (PBR) via RP‐HPLC‐ELSD. Product TAG identities were confirmed by HPLC‐APCI‐MS. Primary differences between the performances of the two reactors were the maximum level of net hydrolysis (ca. 3 and 10 wt‐% lower acylglycerols at equilibrium for the PBR and BR, respectively), the time or space time required to approach quasi‐equilibrium conditions, and less migration of acyl groups in the PBR trials. For the BR trials, quasi‐equilibrium conditions were approached in 4–6 h, while for the PBR trials short space times (15 min to 2 h) were sufficient to produce effluent compositions similar to equilibrium BR compositions. The predominant TAG families formed by interesterification were LLS, PSO, PSL, SSL, and SSO (L = linoleic; S = stearic; P = palmitic; O = oleic). Oxidative stabilities, melting profiles and solid fat contents were determined for selected reaction products.