bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functionalization of Heteropolyanions—Osmium and Rhenium Nitrido Derivatives of Keggin‐ and Dawson‐Type Polyoxotungstates: Synthesis, Characterization and Multinuclear (183W, 15N) NMR, EPR, IR, and UV/Vis Fingerprints
Authors: Dablemont Céline , Hamaker Christopher G. , Thouvenot René , Sojka Zbigniew , Che Michel , Maatta Eric A. , Proust Anna 
Published: November 2006

AbstractReaction of K10[α2‐P2W17O61] or K10[α1‐P2W17O61] or [Bu4N][OsCl4N] in a water/methanol mixture, and subsequent precipitation with (Bu4N)Br provided [α2‐P2W17O61{OsVIN}]7− and [α1‐P2W17O61{OsVIN}]7− Dawson structures as tetrabutylammonium salts. Reactions of [(Bu4N)4][α‐H3PW11O39] with either [ReCl3(N2Ph2)(PPh3)2] or [Bu4N][ReCl4N] are alternatives to the synthesis of [(Bu4N)4][α‐PW11O39{ReVIN}]. 183W and 15N NMR, EPR, IR, and UV‐visible spectroscopies and cyclic voltammetry have been used to characterize these compounds and the corresponding [(Bu4N)4][α‐PW11O39{OsVIN}] Keggin derivative.
Self‐Assembled Ionophores from Isoguanosine: Diffusion NMR Spectroscopy Clarifies Cation's and Anion's Influence on Supramolecular Structure
Authors: Evan‐Salem Tamar , Frish Limor , van Leeuwen Fijs W. B. , Reinhoudt David N. , Verboom Willem , Kaucher Mark S. , Davis Jeffery T. , Cohen Yoram 
Published: November 2006

AbstractCation‐templated self‐assembly of the lipophilic isoguanosine (isoG 1) with different monovalent cations (M+=Li+, Na+, K+, NH4+, and Cs+) was studied in solvents of different polarity by using diffusion NMR spectroscopy. Previous studies that did not use diffusion NMR techniques concluded that isoG 1 forms both pentamers (isoG 1)5⋅M+ and decamers (isoG 1)10⋅M+ in the presence of alkali‐metal cations. The present diffusion NMR studies demonstrate, however, that isoG 1 does not form (isoG 1)5⋅M+ pentamers. In fact, the diffusion NMR data indicates that both doubly charged decamers of formula (isoG 1)10⋅2 M+ and singly charged decamers, (isoG 1)10⋅M+, are formed with lithium, sodium, potassium, and ammonium tetraphenylborate salts (LiB(Ph)4, KB(Ph)4, NaB(Ph)4 and NH4B(Ph)4), depending on the isoG 1:salt stoichiometry of the solution. In the presence of CsB(Ph)4, isoG 1 affords only the singly charged decamers (isoG 1)10⋅Cs+. By monitoring the diffusion coefficient of the B(Ph)4− ion in the different mixtures of solvents, we also concluded that the anion is more strongly associated to the doubly charged decamers (isoG 1)10⋅2 M+ than to the singly charged decamers (isoG 1)10⋅M+. The (isoG 1)10⋅2 M+ species can, however, exist in solution without the mediation of the anion. This last conclusion was supported by the finding that the doubly charged decamers (isoG 1)10⋅2 M+ also prevail in 1:1 CD3CN:CDCl3, a solvent mixture in which the B(Ph)4− ion does not interact significantly with the self‐assembled complex. These diffusion measurements, which have provided new and improved structural information about these decameric isoG 1 assemblies, demonstrate the utility of combining diffusion NMR techniques with conventional NMR methods in seeking to characterize labile, multicomponent, supramolecular systems in solution, especially those with high symmetry.
Catalysis of a Peptidic Micellar Assembly Covalently Immobilized within Mesoporous Silica Channels: Importance of Amphiphilic Spatial Design
Authors: Otani Wataru , Kinbara Kazushi , Zhang Qingmin , Ariga Katsuhiko , Aida Takuzo 
Published: November 2006

AbstractA mesostructured silica/organic composite 1‐MS, constructed from a rodlike micelle of amino acid amphiphile 1 that has a condensable head group and that can be used as a template, was found to be able to catalyze the acetalization of cyclohexanone, in ethanol at 25 °C (50 % in 12 h), whereas no reaction took place with unfunctionalized mesoporous silica. In sharp contrast, hydrolytic removal of the C16 alkyl tail of immobilized 1 resulted in the complete disappearance of the catalytic activity, which suggests the importance of a hydrophobic inner domain for the admission of cyclohexanone. Unsupported peptide amphiphile 2, under identical conditions to those above, was inefficient for acetalization regardless of the absence (2 % in 24 h) or presence of mesoporous silica (7 % in 24 h). Reference composite 2‐MS, which is a noncovalently immobilized peptidic micelle, was virtually inactive (1 % in 24 h). These observations indicate the importance of covalent immobilization of the peptidic rod micelle for catalysis. Mesostructured silicate 3‐MS hybridized with a nonpeptidic, ammonium ion amphiphile (3) showed a certain catalytic activity, but the yield (12 % in 24 h) of the acetal was much lower than that achieved by using 1‐MS as the catalyst. Amorphous silica with immobilized 1 on its surface was much less active than 1‐MS for acetalization (5 % in 24 h).
Effects of 3d–4f Magnetic Exchange Interactions on the Dynamics of the Magnetization of DyIII‐MII‐DyIII Trinuclear Clusters
Authors: Pointillart Fabrice , Bernot Kevin , Sessoli Roberta , Gatteschi Dante 
Published: November 2006

Abstract[{Dy(hfac)3}2{Fe(bpca)2}]⋅ CHCl3 ([Dy2Fe]) and [{Dy(hfac)3}2{Ni(bpca)2}]⋅CHCl3 ([Dy2Ni]) (in which hfac−=1,1,1,5,5,5‐hexafluoroacetylacetonate and bpca−=bis(2‐pyridylcarbonyl)amine anion) were synthesized and characterized. Single‐crystal X‐ray diffraction shows that [Dy2Fe] and [Dy2Ni] are linear trinuclear complexes. Static magnetic susceptibility measurements reveal a weak ferromagnetic exchange interaction between NiII and DyIII ions in [Dy2Ni], whereas the use of the diamagnetic FeII ion leads to the absence of magnetic exchange interaction in [Dy2Fe]. Dynamic susceptibility measurements show a thermally activated behavior with the energy barrier of 9.7 and 4.9 K for the [Dy2Fe] and [Dy2Ni] complexes, respectively. A surprising negative effect of the ferromagnetic exchange interaction has been found and has been attributed to the structural conformation of these trinuclear complexes.
Extraction of Proteins from Biological Fluids by Use of an Ionic Liquid/Aqueous Two‐Phase System
Authors: Du Zhuo , Yu Yong‐Liang , Wang Jian‐Hua 
Published: November 2006

AbstractAn ionic liquid/aqueous two‐phase system based on the hydrophilic ionic liquid 1‐butyl‐3‐methylimidazolium chloride (BmimCl) and K2HPO4 has been employed for direct extraction of proteins from human body fluids for the first time. Proteins present at low levels were quantitatively extracted into the BmimCl‐rich upper phase with a distribution ratio of about 10 between the upper and lower phase and an enrichment factor of 5. Addition of an appropriate amount of K2HPO4 to the separated upper phase results in a further phase separation, giving rise to an improved enrichment factor of 20. FTIR and UV spectroscopy demonstrated that no chemical (bonding) interactions between the ionic liquid and the protein functional groups were identifiable, while no alterations of the natural properties of the proteins were observed. The partitioning of proteins in the two‐phase system was assumed to have been facilitated by the electrostatic potential difference between the coexisting phases, as well as by salting out effects. The system could be applied successfully for the quantification of proteins in human urine after on‐line phase separation in a flow system. The use of an ionic liquid, as a green solvent, offers clear advantages over traditional liquid–liquid extractions, in which the use of toxic organic solvents is unavoidable.
Fluorescent Streptocyanine Dyes: Synthesis and Photophysical Properties – Synthesis of a New Hemicarboxonium Salt
Authors: Guieu Valérie , Izquierdo Albert , Garcia‐Alonso Sonia , André Chantal , Madaule Yves , Payrastre Corinne 
Published: November 2006

AbstractSeven new nonacarbon chain carboxonium salts were synthesized from variously substituted arylethanones, except a few which were too deactivated to react. By the action of several amines, thirteen new nonacarbon chain streptocyanine dyes were synthesized. Photophysical properties of these new dyes were evaluated to highlight that they all absorb around 700 nm and emit fluorescence above 720 nm. As the purity of the intermediary carboxonium salt was improved (up to 98 %), a new nonacarbon chain hemicarboxonium salt was synthesized and fully characterized by X‐ray crystallography.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Remote Trimethylsilyl Groups Interfering with the ortho Deprotonation of Fluoroarenes and Chloroarenes
Authors: Heiss Christophe , Marzi Elena , Mongin Florence , Schlosser Manfred 
Published: November 2006

Abstract(2‐Fluorophenyl)trimethylsilane (2‐F) and (2‐chlorophenyl)trimethylsilane (2‐Cl) react with sec‐butyllithium or lithium 2,2,6,6‐tetramethylpiperidide under permutational hydrogen/metal interconversion (metalation) more slowly than, respectively, the corresponding 4‐fluoro‐ and 4‐chloro isomers (1‐F and 1‐Cl, respectively) or, on the other hand, fluorobenzene and chlorobenzene themselves. The bulky silyl substituent impedes the neighboring halogen to get out of the way when the base attacks the ortho position. For the same reason, (2,4‐difluorophenyl)‐ and (2,4‐dichlorophenyl)trimethylsilane (7‐F and 7‐Cl) are less reactive than their 3,5‐isomers (6‐F and 6‐Cl) and metalation occurs more rapidly at the 4‐ rather than 3‐position of (2,5‐difluorophenyl)‐ and (2,5‐dichlorophenyl)trimethylsilane (5‐F and 5‐Cl, respectively). The decrease in kinetic acidity due to buttressing is most pronounced with the congested substrates (2,4,6‐trihalophenyl)trimethylsilanes (8‐F and 8‐Cl) and, particularly (2,4,6‐trihalophenylene)‐1,3‐bis(trimethylsilanes) (9‐F and 9‐Cl). Fluorine being far less effective than chlorine as a transmitter of steric pressure, (3,4‐ and 2,3‐difluorophenyl)trimethylsilane (3‐F and 4‐F) exhibit comparable reactivity whereas (3,4‐dichlorophenyl)trimethylsilane (3‐Cl) clearly surpasses its 2,3‐dichloro isomer (4‐Cl). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The use of CE‐electrochemiluminescence with ionic liquid for the determination of bioactive constituents in Chinese traditional medicine
Authors: Gao Ying , Xiang Qian , Xu Yuanhong , Tian Yiling , Wang Erkang 
Published: November 2006

AbstractCE / tris(2,2‐bipyridyl) ruthenium(II) (Ru(bpy)32+) electrochemiluminescence (ECL), CE‐ECL, with an ionic liquid (IL) detection system was established for the determination of bioactive constituents in Chinese traditional medicine opium poppy which contain large amounts of coexistent substances. A minimal sample pretreatment which involves a one‐step extraction approach avoids both sample loss and environmental pollution. As the nearby hydroxyl groups in some alkaloid such as morphine may react with borate to form complexes and IL, as a high‐conductivity additive in running buffer, could cause an enhanced field‐amplified effect of electrokinetic injection. Running buffer containing 25 mM borax–8 mM 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMImBF4) IL (pH 9.18) was used which resulted in significant changes in separation selectivity and obvious enhancement in ECL intensities for those alkaloids with similar structures. Sensitive detection could be achieved when the distance between the Pt working electrode and the outlet of separation capillary was set at 150 µm and the stainless steel cannula was fixed approximately 1 cm away from the outlet of the capillary. Quantitative analysis of four alkaloids was achieved at a detection voltage of 1.2 V and a separation voltage of 15 kV in less than 7 min. Detection limits of thebaine, codeine, morphine, and narcotine were 2.5×10−7, 2.5×10−7, 1×10&&minus;9 and 1×10−6 M (S/N = 3), respectively. The method was successfully applied to determine the amounts of opium alkaloids in real poppy samples.
Computation of transmission line magnetic field harmonics
Authors: Faria J. A. Brandão , Almeida M. E. 
Published: November 2006

AbstractThis work presents an accurate procedure to evaluate low‐frequency magnetic fields produced by overhead power line distorted currents containing several harmonic orders. The analysis is conducted in the framework of quasi‐stationary regimes where wave‐propagation phenomena are of little relevance. Bearing in mind that international regulations for safe public exposure to electromagnetic fields establish increasingly stringent reference levels for the magnetic‐field intensity as the frequency increases, the key issue addressed here is whether the presence of higher order harmonics may cause those reference levels to be exceeded. Complying with standard power quality requirements, our analysis considers that the harmonics have prescribed small magnitudes. Computation examples, including balanced and non‐balanced loads, are presented. It is shown that the worst‐case scenario corresponds to the injection of harmonics produced by balanced loads whose order is a multiple of three. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of gypsum board type (X or C) on real fire performance of partition assemblies
Authors: Manzello Samuel L. , Gann Richard G. , Kukuck Scott R. , Lenhert David B. 
Published: November 2006

AbstractThis paper compares the responses of wall‐size partition assemblies, composed of either type X or type C gypsum wallboard panels over steel studs, when each was exposed to an intense room fire. The exposures lasted from the time of ignition to beyond flashover. Heat flux gauges provided time histories of the energy incident on the partitions, while thermocouples provided data on the propagation of heat through the partitions and on the progress toward perforation. Visual and infrared cameras were used to image partition behaviour during the fire exposure. Contraction of the seams of the two types of assemblies occurred under similar thermal conditions on the unexposed surface. However, there were noticeable differences in cracking behaviour. Reduced scale experiments were performed in conjunction with the real‐scale fire tests to provide insight into the contraction and cracking behaviour of the different gypsum board types. Results obtained from these experiments are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Survey of small‐scale flame spread test results of modern fabrics
Authors: Hirschler Marcelo M. , Piansay Timothy 
Published: November 2006

AbstractThe flammability of apparel worn on a person has one of the highest ratios of fire fatalities per fire, and there are few statutory requirements. A series of evaluations was conducted on the flammability of 50 fabrics (both cellulosic and thermoplastic) using the (now withdrawn) NFPA 701 small‐scale test. The fabrics covered a broad range of areal densities (weights) and many were not intended for apparel. A series of conclusions were reached. In particular, it is apparent that the following primary correlation exists between fabric weight and flammability: the heavier the fabric the better it behaves in a fire. Secondarily, however, the type of fabric also strongly affects this conclusion. This paper presents the results of the testing and offers an analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Three‐dimensional instability of axisymmetric flows: solution of benchmark problems by a low‐order finite volume method
Authors: Gelfgat Alexander Y. 
Published: November 2006

AbstractSeveral problems on three‐dimensional instability of axisymmetric steady flows driven by convection or rotation or both are studied by a second‐order finite volume method combined with the Fourier decomposition in the periodic azimuthal direction. The study is focused on the convergence of the critical parameters with mesh refinement. The calculations are done on the uniform and stretched grids with variation of the stretching. Converged results are reported for all the problems considered and are compared with the previously published data. Some of the calculated critical parameters are reported for the first time. The convergence studies show that the three‐dimensional instability of axisymmetric flows can be computed with a good accuracy only on fine enough grids having about 100 nodes in the shortest spatial direction. It is argued that a combination of fine uniform grids with the Richardson extrapolation can be a good replacement for a grid stretching. It is shown once more that the sparseness of the Jacobian matrices produced by the finite volume method allows one to enhance performance of the Newton and Arnoldi iteration procedures by combining them with a direct sparse linear solver instead of using the Krylov‐subspace‐based iteration methods. Copyright © 2006 John Wiley & Sons, Ltd.
Numerical simulation of thin airfoil stall by using a modified DES approach
Authors: Li Dong 
Published: November 2006

AbstractThe detached‐Eddy simulation (DES) method was applied to calculate pre‐ and post‐stall aerodynamic characteristics of airfoil stall. A discrepancy between numerical and experimental data was observed near the stall regime for the airfoil NACA64A‐ 006 which is a thin airfoil stall type. The reason of this discrepancy and one possible way for improvement of the numerical model are discussed here. It is shown that the use of the Baldwin–Lomax model in the RANS region improves the DES results in this case. If the relevant factors (grid density, time step, turbulence model, etc.) are appropriately taken into account, the DES approach could reliably predict stall aerodynamical characteristics. Copyright © 2006 John Wiley & Sons, Ltd.
Sex‐specific QTL effects on variation in paraoxonase 1 (PON1) activity in Mexican Americans
Authors: Winnier Deidre A. , Rainwater David L. , Cole Shelley A. , Williams Jeff T. , Dyer Thomas D. , Blangero John , MacCluer Jean W. , Mahaney Michael C. 
Published: November 2006

AbstractParaoxonase 1 (PON1), a high‐density lipoprotein‐associated enzyme known to protect against cellular damage from toxic agents, may also have antioxidant properties. PON1 activity levels have been reported to differ by sex in human and animal studies with females exhibiting higher basal levels. We measured PON1 activity frozen serum for 1,406 individuals in over 40 extended pedigrees from the San Antonio Family Heart Study (SAFHS). We used a maximum likelihood‐based, variance decomposition approach implemented in SOLAR to test for genotype‐by‐sex (G × S) interaction on variation in PON1 activity and to determine if any of the four PON1 quantitative trait loci (QTL) previously reported by us for this population might account for sex differences in PON1 activity levels. The residual additive genetic correlation (ρG = 0.82) between males and females is significantly different from 1 (P = 0.009), suggesting that some of the genes that influence PON1 activity act differently in females and males or, possibly, that a different combination of genes influences this trait in each sex. In addition to the QTL at or near the PON structural locus on 7q21‐22, three other potential QTLs were evaluated for sex‐specific effects: one each on chromosomes 12, 17 and 19. The QTL on chromosome 17 (LOD = 2.32, P = 0.0003; flanked by microsatellite marker loci D17S974 and D17S969) shows a significant (P = 0.005) sex‐specific effect on PON1 activity; accounting for 6% of the additive genetic variance in males and 20% in females. This study represents the first formal statistical genetic test for G × S interactions on normal quantitative variation in PON1 activity in humans. Genet. Epidemiol. © 2006 Wiley‐Liss, Inc.
ROCK inhibition with Y27632 activates astrocytes and increases their expression of neurite growth‐inhibitory chondroitin sulfate proteoglycans
Authors: Chan Carmen C. M. , Wong Angel K. , Liu Jie , Steeves John D. , Tetzlaff Wolfram 
Published: November 2006

AbstractInhibition of Rho‐kinase (ROCK) with Y27632 stimulates sprouting by injured corticospinal tract and dorsal column tract axons, and accelerates functional recovery. However, regeneration of these axons across the glial scar was not observed. Here we examined the effects of Y27632 treatment on chondroitin sulfate proteoglycan (CSPG) expression by astrocytes, which are a key component of the reactive gliosis inhibiting axonal regeneration. In vivo, rats underwent a dorsal column transection and were treated with Y27632 via intrathecal pump infusion. Compared with controls, Y27632‐treated injury sites displayed exaggerated upregulation of glial fibrillary acid protein and neurocan immunoreactivity along the lesion edge. In vitro, astrocytes assumed a reactive morphology (stellate shape) and increased their expression of CSPGs after Y27632 treatment. Neurite growth by dissociated cortical neurons decreased when cultured on the extracellular matrix (ECM) derived from Y27632‐treated astrocytes. This decrease in neurite growth was reversed with chondroitinase‐ABC (ChABC) digestion, indicating that the inhibition was due to CSPG depositions within the ECM. Interestingly, conditioned medium (CM) from untreated astrocytes was inhibitory to neurite growth, which was overcome by ChABC digestion. Such inhibitory activity was not found in the CM of Y27632‐treated astrocytes. Taken together, these data support a model where ROCK inhibition by Y27632 modifies astrocytic processing of CSPGs, and increases the presence of CSPGs within the ECM while reduces CSPGs in the CM (cerebrospinal fluid in vivo). This increased expression of inhibitory CSPGs in the ECM of the glial scar may counteract the growth promoting effects of ROCK inhibition on axonal growth cones. © 2006 Wiley‐Liss, Inc.
Rapid detection of metastasis of gastric cancer using reverse transcription loop‐mediated isothermal amplification
Authors: Horibe Daisuke , Ochiai Takenori , Shimada Hideaki , Tomonaga Takeshi , Nomura Fumio , Gun Ma , Tanizawa Tohru , Hayashi Hideki 
Published: November 2006

AbstractTailor‐made surgeries for patients with solid malignancies have been under consideration on the basis of the development of new approaches for minor metastatic foci of malignant tumors. Accurate and reliable methods to detect metastases in biopsy specimens with certain rapidity are essential for the performance of these surgeries. The aim of this study was to develop a rapid and practical method to detect metastasis in specimens from patients with gastric carcinoma with the use of reverse transcription loop‐mediated isothermal amplification (RT‐LAMP) reaction, a novel technique for detecting mRNA expressions of targeted sequences with high sensitivity, specificity and rapidity under isothermal conditions. RT‐LAMP primers to detect cytokeratin19 (CK19) mRNA were generated and 92 lymph nodes (LNs) obtained from 9 patients with gastric cancer were tested for tumor metastases with this technique. Among 92 LNs, 15 were metastasis‐positive by routine histopathological examination. RT‐LAMP reaction detected CK19 expression in all of the pathologically positive LNs and in 16 of 77 negative LNs. Nested RT‐PCR assay for CK19 expression was also performed on 2 of the 9 cases including 32 LNs. The agreement rate of CK19 expression detection by RT‐LAMP and RT‐PCR analysis was 31/32 (97%). The RT‐LAMP technique showed similar sensitivity to detect metastases as nested RT‐PCR assay, with a rapidity comparable to that of intraoperative histopathological examination with frozen sectioning and hematoxylin and eosin staining. This method is expected to play an essential role in the performance of tailor‐made surgeries in the near future. © 2006 Wiley‐Liss, Inc.