bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rigidity and gamma convergence for solid‐solid phase transitions with SO(2) invariance
Authors: Conti Sergio , Schweizer Ben 
Published: January 2006

AbstractThe singularly perturbed two‐well problem in the theory of solid‐solid phase transitions takes the formwhereu: Ω ⊂ ℝn→ ℝnis the deformation, andWvanishes for all matrices inK= SO(n)A∪ SO(n)B. We focus on the casen= 2 and derive, by means of Gamma convergence, a sharp‐interface limit forIε. The proof is based on a rigidity estimate for low‐energy functions. Our rigidity argument also gives an optimal two‐well Liouville estimate: if ∇uhas a small BV norm (compared to the diameter of the domain), then, in theL1sense, either the distance of ∇ufrom SO(2)Aor the one from SO(2)Bis controlled by the distance of ∇ufromK. This implies that the oscillation of ∇uin weakL1is controlled by theL1norm of the distance of ∇utoK. © 2006 Wiley Periodicals, Inc.
Decay of correlations and the central limit theorem for meromorphic maps
Authors: Dinh Tien‐Cuong , Sibony Nessim 
Published: January 2006

AbstractLet f be a dominant meromorphic self‐map of large topological degree on a compact Kähler manifold. We give a new construction of the equilibrium measure μ of f and prove that μ is exponentially mixing. As a consequence, we get the central limit theorem in particular for Hölder‐continuous observables, but also for noncontinuous observables. © 2005 Wiley Periodicals, Inc.
Long‐time dynamics of KdV solitary waves over a variable bottom
Authors: Dejak Steven I. , Sigal Israel Michael 
Published: January 2006

AbstractWe study the variable‐bottom, generalized Korteweg—de Vries (bKdV) equation ∂tu = −∂x(∂u + f(u) − b(t,x)u), where f is a nonlinearity and b is a small, bounded, and slowly varying function related to the varying depth of a channel of water. Many variable‐coefficient KdV‐type equations, including the variable‐coefficient, variable‐bottom KdV equation, can be rescaled into the bKdV. We study the long‐time behavior of solutions with initial conditions close to a stable, b = 0 solitary wave. We prove that for long time intervals, such solutions have the form of the solitary wave whose center and scale evolve according to a certain dynamical law involving the function b(t,x) plus an H1(ℝ)‐small fluctuation. © 2005 Wiley Periodicals, Inc.
Form boundedness of the general second‐order differential Operator
Authors: Maz′ya Vladimir G. , Verbitsky Igor E. 
Published: January 2006

AbstractWe give explicit necessary and sufficient conditions for the boundedness of the general second‐order differential operatorwith real‐ or complex‐valued distributional coefficientsaij,bj, andc, acting from the Sobolev spaceW1, 2(ℝn) to its dualW−1, 2(ℝn). This enables us to obtain analytic criteria for the fundamental notions of relative form boundedness, compactness, and infinitesimal form boundedness of ℒ︁ with respect to the Laplacian onL2(ℝn).In particular, we establish a complete characterization of the form boundedness of the Schrödinger operator$(i \nabla + \vec{a})^2 + q$with magnetic vector potential$\vec{a} \in L^2_{{\rm loc}} (R^{n})^{n}$andq∈D′(ℝn). © 2005 Wiley Periodicals, Inc.
Study of the Pm$\bar 3$n Space Group of Cubic Mesoporous Silica
Authors: Han Shuhua , Hou Wanguo , Xu Jun , Huang Xirong , Zheng Liqiang 
Published: January 2006

AbstractBy using a Gemini surfactant, [C14H25N+(CH3)2(CH2)2N+(CH3)2C14H25]⋅2 Br−(C14‐2‐14), with a short spacer group (s=2) as structure‐directing agent and sodium silicate as precursor, high‐quality, ordered cubic mesoporous silica with space group Pm$\bar 3$n was prepared by the S+I−route (S=surfactants, I=precursor). The samples were characterized by small‐angle X‐ray diffraction, transmission electron microscopy, and N2 adsorption–desorption. The results showed that the pore structure of the resulting mesoporous silica belonged to the cubic system (space group Pm$\bar 3$n). The unit‐cell parameter of the cubic system was in the range of 8.81–9.14 nm. The high‐quality cubic mesoporous structure was formed at molar ratios of C14‐2‐14to sodium silicate of 0.33:1 to 0.16:1 and a molar ratio of ethyl acetate to sodium silicate of 2:1. N2 adsorption–desorption curves revealed type IV isotherms and H1 hysteresis loops. The primary pore volume, and the most probable pore size according to the Barrett–Joyner–Halenda (BJH) model, increased with increasing molar ratio of C14‐2‐14to sodium silicate.
Asbestos Mineral Analysis by UV Raman and Energy‐Dispersive X‐ray Spectroscopy
Authors: Petry Renate , Mastalerz Remigius , Zahn Stefan , Mayerhöfer Thomas G. , Völksch Günther , Viereck‐Götte Lothar , Kreher‐Hartmann Birgit , Holz Lothar , Lankers Markus , Popp Jürgen 
Published: January 2006

AbstractThe applicability of a UV micro‐Raman setup was assessed for the rapid identification of fibrous asbestos minerals using 257 and 244 nm laser light for excitation. Raman spectra were obtained from six asbestos reference standards belonging to two basic structural groups: the serpentines (chrysotile) and the amphiboles (crocidolite, tremolite, amosite, anthophyllite, and actinolite). The UV Raman spectra reported here for the first time are free from fluorescence, which is especially helpful in assessing the hydroxyl‐stretching vibrations. The spectra exhibit sharp bands characteristic of each asbestos species, which can be used for the unambiguous identification of known and unknown asbestos fibres. Evident changes of the relative band intensities sensitively reflect the chemical substitutions that typically occur in asbestos minerals. The elemental composition of the asbestos reference samples was analysed by using a scanning electron microscope equipped with an energy‐dispersive X‐ray (EDX) spectrometer. The discussion of the experimental results in terms of EDX analysis sheds new light on the structural and vibrational consequences of cation distribution in asbestos minerals.
Synthesis and Photoluminescence of Titania Nanoparticle Arrays Templated by Block‐Copolymer Thin Films
Authors: Sun Zaicheng , Kim Dong Ha , Wolkenhauer Markus , Bumbu Gabriela Gina , Knoll Wolfgang , Gutmann Jochen S. 
Published: January 2006

AbstractHigh‐density arrays of titania nanoparticles were prepared using a polystyrene‐b‐poly(ethylene oxide) block copolymer (PS‐b‐PEO) as a template and a titanium tetraisopropoxide based sol–gel precursor as titania source via a spin‐coating method. The hydrophilic titania sol–gel precursor was selectively incorporated into hydrophilic PEO domains of PS‐b‐PEO and form titania nanoparticle arrays, due to a microphase separation between the PS block and the sol–gel/PEO phase. Field emission scanning electron microscopy (FESEM) and scanning probe microscopy (SPM) images showed that the uniformity and long‐range order of the titania/PEO domains improved with increasing sol–gel precursor amount. Grazing incidence small‐angle X‐ray scattering (GISAXS) results indicate that the ordered structures exist over large length scales. Titania nanocrystal arrays of anatase modification were obtained by calcination at 600 °C for 4 h. After calcination, separated particles were observed for low and medium amounts of sol–gel precursors. Films with higher precursor amounts showed wormlike structures due to the aggregation between neighboring particles. Removal of the polymer matrix via UV treatment leads to highly ordered arrays of amorphous titania while retaining the domain size and interparticle distance initially present in the hybrid films. Photoluminescence (PL) properties were investigated for samples before and after calcination. The PL intensity increases with the increasing amount of sol–gel precursor. Bands at 412 nm were ascribed to self‐trapped exitons and bands at 461 and 502 nm to oxygen vacancies, respectively. Uncalcined or UV‐treated samples also showed PL properties similar to calcined samples, indicating that the local environment of the titanium atoms is similar to the environment of the crystalline anatase modification.
The multi‐faceted cross‐talk between the insulin and angiotensin II signaling systems
Authors: Velloso Licio A. , Folli Franco , Perego Lucia , Saad Mario J. A. 
Published: January 2006

AbstractInsulin and angiotensin II are hormones that play pivotal roles in the control of two vital and closely related systems, the metabolic and the circulatory systems, respectively. A failure in the proper action of each of these hormones results, to a variable degree, in the development of two highly prevalent and commonly overlapping diseases—diabetes mellitus and hypertension. In recent years, a series of studies has revealed a tight connection between the signal transduction pathways that mediate insulin and angiotensin II actions in target tissues. This molecular cross‐talk occurs at multiple levels and plays an important role in phenomena that range from the action of anti‐hypertensive drugs to cardiac hypertrophy and energy acquisition by the heart. At the extracellular level, the angiotensin‐converting enzyme controls angiotensin II synthesis but also interferes with insulin signaling through the proper regulation of angiotensin II and through the accumulation of bradykinin. At an early intracellular level, angiotensin II, acting through JAK‐2/IRS‐1/PI3‐kinase, JNK and ERK, may induce the serine phosphorylation and inhibition of key elements of the insulin‐signaling pathway. Finally, by inducing the expression of the regulatory protein SOCS‐3, angiotensin II may impose a late control on the insulin signal. This review will focus on the main advances obtained in this field and will discuss the implications of this molecular cross‐talk in the common clinical association between diabetes mellitus and hypertension. Copyright © 2006 John Wiley & Sons, Ltd.
Determinants of glycaemic control in type 1 diabetes during intensified therapy with multiple daily insulin injections or continuous subcutaneous insulin infusion: importance of blood glucose variability
Authors: Pickup John C. , Kidd Julia , Burmiston Sheila , Yemane Nardos 
Published: January 2006

AbstractBackground and methodsWe investigated the factors that determine the best glycaemic control on multiple daily insulin (MDI) injections and continuous subcutaneous insulin infusion (CSII), and the hypothesis that blood glucose variability is a major determinant of control and that the resultant HbA1c on MDI correlates with the improvement achieved by CSII. We studied 30 type 1 diabetic subjects already receiving MDI. Renewed attempts to improve control on MDI were made for a median of five months, and then the subjects were switched to CSII. The variability of within‐day and between‐day blood glucose concentrations was calculated from blood glucose self‐monitoring data.ResultsHbA1c during MDI varied from 5.7 to 11.7% (mean ± SD, 8.5 ± 1.4%). Within‐ and between‐day blood glucose variability correlated with HbA1c on MDI (r = 0.59, p < 0.001; r = 0.48, p < 0.03). Within‐day variability remained an independent predictor of HbA1c on MDI. Mean HbA1c improved with CSII (to 7.3 ± 0.9%, p < 0.001), but reduction in HbA1c was variable and was related to the HbA1c on MDI (r = 0.79, p < 0.001) and within‐day variability (r = 0.56, p < 0.01). Similar results were observed for subjects treated only with glargine‐based MDI.ConclusionsThe best glycaemic control achievable on MDI is related to blood glucose variability—those with the largest swings in blood glucose retaining the highest HbA1c. The improvement in control achieved by CSII is related to HbA1c and blood glucose variability on MDI. Pump therapy is most effective in those worst controlled on MDI. Copyright © 2006 John Wiley & Sons, Ltd.
Chiral, Enantiopure Aluminum(III) and Titanium(IV) Azatranes
Authors: Forcato Massimiliano , Lake Fredrik , Mba Blazquez Myriam , Renner Patrick , Crisma Marco , Gade Lutz H. , Licini Giulia , Moberg Christina 
Published: January 2006

AbstractAlIII and TiIV complexes of C3‐symmetric tetradentate trisamidoamine ligands with trigonal bipyramidal coordination geometry, containing chlorine or dialkylamido groups, or with a free coordination site in the apical position, have been synthesised by salt metathesis and amine elimination. Products with threefold symmetry were generally obtained for tetravalent titanium, whereas for the aluminium complexes either asymmetric structures with two of the three podand arms taking part in coordination to the metal or symmetric arrangements possessing the full threefold symmetry were formed depending on the steric properties of the ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Molecular Structures and Magnetism of Mn12 Nanomagnets Containing the 3‐Thiophenecarboxylate Ligand
Authors: Lim Jin Mook , Do Youngkyu , Kim Jinkwon 
Published: January 2006

AbstractThe new Mn12 single‐molecule magnets containing thiophenyl ligands, [Mn12O12(O2CC4H3S)16(HO2CC4H3S)(H2O)2]·5CH2Cl2(1) and [Mn12O12(O2CC4H3S)16(H2O)4]·6CH2Cl2·2H2O (2), have been synthesized by ligand‐substitution reactions of 3‐thiophenecarboxylic acid and [Mn12O12(O2CCH3)16(H2O)4] and investigated by magnetic measurements with a SQUID magnetometer. The X‐ray analysis of 1 shows five‐coordination geometry around the MnIII ion due to the unusual coordination of 3‐thiophenecarboxylic acid to the MnIII ion. Compound 1 displays two different rates of magnetization relaxation, which are faster than that of compound 2 because of structural distortion in the Mn12 complex of 1. Magnetic susceptibility measurements on 1 and 2 give the following parameters: Ueff (the faster relaxation form of 1) = 51.81 K, 1/τ0 = 1.90·108 s–1; Ueff (the slower relaxation form of 1) = 66.44 K, 1/τ0 = 1.50·108 s–1; Ueff(2) = 67.09 K, 1/τ0 = 1.32·108 s–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
New Ligands for Rh‐Catalysed Hydroformylation of 1‐Octene in Supercritical Carbon Dioxide – X‐ray Structure of [Rh{PPh2(OC9H19)}4]PF6
Authors: Giménez‐Pedrós Marta , Aghmiz Ali , Ruiz Núria , Masdeu‐Bultó Anna M. 
Published: January 2006

AbstractThe new P‐donor ligands PPh3–n(OC9H19)n (n = 3, 2, 1) containing branched alkyl chains were synthesised and their coordination to RhI and PdII studied. The X‐ray structure of [Rh{PPh2(OC9H19)}4]PF6 was determined. Reaction of the [Rh(acac)(CO)2]/PPh3–n(OC9H19)n systems with CO/H2 at 5 atm and 80 °C in toluene led to the formation of [RhH(CO){PPh3–n(OC9H19)n}3] as the main species. The Rh‐catalysed hydroformylation of 1‐octene with these ligands was investigated in supercritical carbon dioxide (scCO2) and toluene as solvents. Although the catalytic systems are not soluble in scCO2, they are active. The activities are higher in toluene than in scCO2 but the selectivities for aldehydes in the case of the phosphonite derivative are higher in the supercritical medium than in toluene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Strained Dehydrobenzoannulenes
Authors: Hisaki Ichiro , Sonoda Motohiro , Tobe Yoshito 
Published: January 2006

AbstractDehydrobenzoannulenes (DBAs) have been attracting a great deal of interest as a result of their potential applications as optoelectronic materials, precursors of new forms of carbon materials, and as building blocks for hitherto‐unknown 2D carbon networks consisting of sp and sp2 carbon atoms. Among the DBAs, those with substantial strain due to bond‐angle deformation at the triple bonds exhibit greater potential as electronic communication units and precursors of new polycyclic, conjugated ring systems owing to their high reactivity towards carbon–carbon bond‐forming reactions. It is also of interest to see how the deformation of triple bonds affects the cyclic conjugation of π systems, that is, the aromaticity/antiaromaticity of DBAs. This article reviews these characteristic aspects of strained DBAs. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Selective and Rapid Access to Six‐ or Seven‐Membered Ring Iminosugars via 6,8‐Diazabicyclo[3.2.1]oct‐6‐ene Intermediates
Authors: Tite Tony , Tsimilaza Andriamihamina , Lallemand Marie‐Christine , Tillequin François , Leproux Pascale , Libot Francine , Husson Henri‐Phillipe 
Published: January 2006

AbstractA selective and rapid access to six‐ or seven‐membered ring iminosugars is reported. The key step of the strategy involves the highly regio‐ and stereoselective reduction of 6,8‐diazabicyclo[3.2.1]oct‐6‐ene intermediates, depending on the nature of imine substituents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Solvent‐Free Carbon–Oxygen Bond Formation Catalysed by CeCl3·7 H2O/NaI: Tetrahydropyranylation of Hydroxy Groups
Authors: Bartoli Giuseppe , Giovannini Riccardo , Giuliani Arianna , Marcantoni Enrico , Massaccesi Massimo , Melchiorre Paolo , Paoletti Melissa , Sambri Letizia 
Published: January 2006

AbstractAn efficient and highly chemoselective method fo the protection of free hydroxy compounds with 3,4‐dihydro‐2H‐pyran is reported. Since the deprotection of THP‐ethers occurs very readily at room temperature, the successful use of this type of protecting group depends only upon how readily it can be introduced. For this we have examined the tetrahydropyranylation of alcohols and phenols catalysed by the CeCl3·7 H2O/NaI system surface under solvent‐free conditions. The reaction presents the advantage of being performable under extremely mild conditions by use of catalytic amounts of an interesting Lewis acidic system consisting of the CeCl3·7 H2O/NaI catalyst combination, which can be easily separated from the reaction mixture. The advantages of this procedure, which utilizes cheap and “friendly” reagents, over the previously reported ones are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Ring‐Closing Metathesis Pathway to Fluorovinyl‐Containing Nitrogen Heterocyles
Authors: De Matteis Valeria , van Delft Floris L. , Tiebes Jörg , Rutjes Floris P. J. T. 
Published: January 2006

AbstractThe synthesis of highly functionalized fluorinated piperidines is described. The key step in this synthesis is a ring‐closing metathesis reaction involving fluoride‐substituted olefins, which leads to the corresponding cyclic vinyl fluorides. Several sequences to arrive at differently substituted piperidines have been evaluated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Fluorous Capping Strategy for Fmoc‐Based Automated and Manual Solid‐Phase Peptide Synthesis
Authors: Montanari Vittorio , Kumar Krishna 
Published: January 2006

AbstractJust add water: Peptides synthesized by the use of standardized Fmoc protocols with commercial automated synthesizers can be purified from deletion products by simple centrifugation of aqueous solutions. The deletion products are capped with fluorous trivalent iodonium salts. At the end of the synthesis, the crude peptide is dissolved in water and centrifuged, and the deletion products precipitate leaving only the full length peptide in solution. Protocols for generalized use of this strategy are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Signal Generation at an Electrochemical Immunosensor via the Direct Oxidation of an Electroactive Label
Authors: Akram Mohammad , Stuart Margaret C. , Wong Danny K. Y. 
Published: January 2006

AbstractIn this paper, we report the development of an electrochemical immunosensor with a direct signal generation scheme. To achieve this, ferrocenecarboxylic acid was conjugated as an electroactive label to an immunocomplex immobilized on an electrochemically pretreated glassy carbon electrode. The pregnancy hormone and tumor marker, human chorionic gonadotrophin (hCG), was employed as a model analyte. Direct oxidation of ferrocenecarboxylic acid facilitated a signal generation scheme for the quantification of hCG at the immunosensor. Evaluation of the immunosensor performance has yielded statistically acceptable agreement in hCG levels present in several human serum samples compared to those reported by a Sydney hospital.
Rapid extraction and analysis of volatile organic compounds of Iranian feverfew (Tanacetum parthenium) using headspace solvent microextraction (HSME), and gas chromatography/mass spectrometry
Authors: Besharati‐Seidani A. , Jabbari A. , Yamini Y. , Saharkhiz M. J. 
Published: January 2006

AbstractIn the present study, we have utilized headspace solvent microextraction (HSME) as a modern and rapid sample preparation method for the isolation and preconcentration of the volatile organic compounds (VOCs) from the headspace of a plant into a microdrop. The extraction was done by suspending a microliter drop of the solvent from the tip of a microsyringe to the headspace of dried and powdered feverfew flowers (Tanacetum parthenium) in a sealed vial for a preset extraction time. Then, the microdrop was retracted back into the microsyringe and injected directly into a GC injection port. In this study, the identification of the VOCs extracted by HSME was confirmed according to their retention indices and mass spectra (EI, 70 eV) and quantitative analysis was performed by GC‐FID. Parameters such as the nature of the extracting solvent, particle size of the sample, temperatures of the microdrop and sample, volumes of the microdrop and sample and the extraction time were studied and optimized and the method performance was evaluated. The optimized conditions were: sample particle size, 0.65 mm; sample volume, 8 ml (in a 15 ml vial); sample temperature, 50 °C; microsyringe needle temperature, 25 °C (room temperature); microdrop volume, 3 µl and extraction time, 8 min. Finally, under optimum working conditions, the percentage of the VOCs extracted from the headspace and the relative standard deviation of the extraction for each compound based on seven replicated analyses were evaluated. Copyright © 2006 John Wiley & Sons, Ltd.
Chemical composition of the volatile oil of aerial parts of Valeriana sisymbriifolia Vahl. grown in Iran
Authors: Javidnia K. , Miri R. , Kamalinejad M. , Khazraii H. 
Published: January 2006

AbstractThe essential oil of Valeriana sisymbriifolia growing wild in Iran was obtained by hydrodistallation and analyzed by GC‐MS technique. Forty‐one components representing 90.2% of the total oil were identified. The main components of the oil were β‐atlantone and 14‐hydroxy‐9‐epi‐(E)‐caryophyllene (16.3%), viridiflorol (11.4%), isovaleric acid (7.3%), (Z)‐α‐bisabolene (5.9%), allo‐aromadendrene‐epoxide (5.5%) and borneol (5.2%). Copyright © 2006 John Wiley & Sons, Ltd.
Geranium (Pelargonium sp. ‘hybrid’) essential oil in subtropical and temperate regions of Jammu and Kashmir
Authors: Bhan M. K. , Dhar A. K. , Choudhary D. K. , Rekha Kanti , Balyan S. S. , Khan S. , Agarwal S. G. , Shawl A. S. 
Published: January 2006

AbstractSix accessions of geranium (Pelargonium sp. ‘hybrid’) were introduced in temperate and subtropical regions of Jammu and Kashmir. The herbaceous parts in the commercial distillation gave 0.09–0.13% oil on fresh weight basis. The calculated herbage yield (tonnes/ha) and oil yield (litre/ha) varied from 31.5 ± 1.87 to 49.1 ± 2.73 and 32.40 to 57.12, respectively. The geranium oil produced in different regions of Jammu and Kashmir was comparable to that produced in other geranium‐growing areas in India in terms of its major constituents, citronellol (22.5–34.5%) and geraniol (13.9–24.7%), respectively. This suggests that geranium can be successfully grown in the state of Jammu and Kashmir. Copyright © 2006 John Wiley & Sons, Ltd.
Chemical composition of the essential oils of Rubia tinctorum L. aerial parts from Iran
Authors: Navaei Mehrdokht Najafpour , Mirza Mehdi , Dini Mohammad 
Published: January 2006

AbstractHydro‐distilled volatile oil from the aerial parts of Rubia tinctorum L. was obtained at yield of 0.1% w/w based on dry weight. The oil was analyzed by a combination of GC and GC‐MS. Thirty‐four components were identified, constituting 96.4% of the oil. The major constituents in the oil were pentadecanal (20.2%), tridecanal (16.7%) and globulol (7.8%). Copyright © 2006 John Wiley & Sons, Ltd.