bluuebunny/crossref_metadata_2025 huggingface dataset:
A DFT study of transition structures and reactivity in solvolyses of tert‐butyl chloride, cumyl chlorides, and benzyl chlorides
Authors: Ruff Ferenc , Farkas Ödön
Published: December 2007

DFT computations were performed on the SN1 and SN2 solvolyses of substituted cumyl chlorides and benzyl chlorides in ethanol and water, by increasing stepwise the CCl distance and by optimization. The total energy increases with the increase in the ClC distance in SN1 reactions, while free energy of activation pass through maximum. To validate the results, the calculated free energies of activation were compared with data obtained by kinetic measurements. The structural parameters of the transition states were correlated with the Hammett substituent constants and compared with the data of hydrolyses of tert‐butyl chloride and methyl chloride, which proceed with known mechanisms. Conclusions on the mechanisms of the reactions were driven from the effect of substituents on free energies of activation. Cumyl chlorides substituted with electron‐donating (e‐d) groups solvolyze with SN1 mechanism, while the reactions of substrates that bear electron‐withdrawing groups proceed with weak nucleophilic assistance of the solvent. Benzyl chlorides hydrolyze through an SN2 pathway except those derivatives that have strongly e‐d groups, where the reaction has SN1 character, but a weak nucleophilic assistance of the water should also be taken into consideration. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of poly(ethyl acrylate) by single electron transfer‐degenerative chain transfer living radical polymerization in water catalyzed by Na2S2O4
Authors: Coelho Jorge F. J. , Carvalho Erica Y. , Marques Dina S. , Popov Anatoliy V. , Percec Virgil , Gonçalves Pedro M. F. O. , Gil M. H.
Published: December 2007

Living radical polymerization of ethyl acrylate was achieved by single‐electron‐transfer/degenerative‐chain transfer mediated living radical polymerization in water catalyzed by sodium dithionite. The plots of number‐average molecular weight versus conversion and ln[M]0/[M] versus time are linear, indicating a controlled polymerization. This method leads to the preparation of α,ω‐di(iodo)poly(ethyl acrylate) (α,ω‐di(iodo)PEtA) macroinitiator that can be further functionalized. The molecular weight distributions were determined using a combination of three detectors (TriSEC): right‐angle light scattering, a differential viscometer and refractive index. The method studied in this work represents a possible route to prepare well‐tailored macromolecules made of ethyl acrylate in environmental friendly reaction medium. To the best of our knowledge there is no previous report dealing with the synthesis of PEtA by any LRP approach in aqueous medium. Furthermore, the method described in this article was successfully applied in pilot scale reactions under industrial production conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 421–432, 2008
Appreciable norbornene incorporation in the copolymerization of ethylene/norbornene using titanium catalysts containing trianionic N[CH2CH(Ph)O]33− ligands
Authors: Sudhakar Padmanabhan
Published: December 2007

The newly synthesized 1‐TiCl (C3 symmetric) and 2‐TiCl (Cs symmetric) precatalysts in combination with MAO polymerized ethylene, cyclic olefins, and copolymerized ethylene/norbornene in good yields. The catalyst with C3 symmetry exhibits moderate catalytic activity and efficient norbornene incorporation for E/NBE copolymerization in the presence of MAO [activity = 360 kg polymer/(mol Ti h), ethylene 1 atm, NBE 5 mmol/mL, 10 min], affording poly(ethylene‐co‐NBE)s with high norbornene contents (42.0%) and the Cs symmetric catalyst showed an activity of 420 kg polymer/(mol Ti h), ethylene 1 atm, NBE 5 mmol/mL affording poly(ethylene‐co‐NBE)s with 33.0% norbornene content. The effect of monomer concentration at ambient temperature and constant Al/Ti ratio for the homo and copolymerization was studied in a detailed manner. We found that apart from the electronic environment around the metal center the steric environment provided by the symmetry of the catalyst systems has a considerable influence on the percentage of norbornene content of the copolymer obtained. We also found that with a given catalyst a variable clearly influencing the copolymer microstructure, hence also the copolymer properties, is the monomer concentration at a given feed ratio. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 444–452, 2008
Specific stimuli‐responsive antipolyelectrolyte swelling of amphiphilic gel based on methacryloxyethyl dimethyloctane ammonium bromide
Authors: Xu Ling , Zhai Maolin , Huang Ling , Peng Jing , Li Jiuqiang , Wei Genshuan
Published: December 2007

An amphiphilic electrolyte, methacryloxyethyl dimethyloctane ammonium bromide (MODAB), was synthesized by quaternization of dimethylaminoethyl methacrylate (DMAEMA) with 1‐bromooctane. Then amphiphilic PMODAB gel was synthesized by radiation cross‐linking with ethyleneglycol dimethacrylate as cross‐linker. PMODAB gels possess distinguished different swelling behaviors with those of DMAEMA hydrogels: (1) Antipolyelectrolyte phenomenon was observed in NaCl solution, that is, a remarkable increment of equilibrium degree of swelling (EDS) in the low NaCl concentration region (10−4 to 10−3 mol L−1), followed by a significant decrease (10−3 to 0.2 mol L−1), and a collapsed state (>0.2 mol L−1); (2) Compared with PDMAEMA, PMODAB was a temperature‐sensitive polymer which showed an upper critical solution temperature (UCST) behavior. The EDS of PMODAB gel dramatically increased at the UCST; (3) In the 0.2 mol L−1 NaCl solutions, PMODAB gel swelled more significantly in a basic condition (pH > 10) than that in an acidic condition. The special volume phase transition behavior of PMODAB gel is ascribed to the hydrophobic interaction between octyl groups and the formation of ion‐cluster between tetra‐alkyl ammonium cation and Br−, which lead to the aggregation of gel structure and could be affected by the composition and temperature of the surrounding solution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 473–480, 2008
Monodispersed PEG‐b‐PSt nanoparticles prepared by atom transfer radical emulsion polymerization under microwave irradiation
Authors: Xu Zushun , Hu Xiaoxi , Li Xiaoqin , Yi Changfeng
Published: December 2007

Atom transfer radical emulsion polymerization of styrene using PEG‐Cl as macroinitiator under microwave irradiation was successfully conducted and monodispersed nanoparticles were prepared. The PEG‐Cl macroinitiator was synthesized, and confirmed by FTIR spectrum. The structure of the PEG‐b‐PSt diblock copolymer was characterized by 1H‐NMR and the number of styrene unit in the diblock copolymer was calculated. The morphology, size, and size distribution of the nanoparticles were characterized by transmission electron microscope (TEM) and photon correlation spectroscopy (PCS). The effects of the ratio of macroinitiator and monomer, the ratio of catalyst and macroinitiator on the size and size distribution of nanoparticles were investigated. It was found that the diameters of PEG‐b‐PSt nanoparticles prepared under microwave irradiation were smaller (<50 nm) and more monodispersed than those prepared with conventional heating. Moreover, with the increasing of the ratio of St/PEG‐Cl, the hydrodynamic diameters (Dh) of the nanoparticles increased and the poly index decreased, both Dh and poly index of the nanoparticles prepared under microwave irradiation were smaller then those prepared with conventional heating; as the concentration of catalyst increased, the Dh of the nanoparticles decreased and the poly index of the nanoparticles increased. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 481–488, 2008
Luminescence properties of soluble 2,2′,7,7′‐Tetrakis(2‐(9‐hexyl‐9H‐carbazol‐3‐yl)‐vinyl)‐9,9′‐spirobifluorene‐labeled dendrimers: Photoluminescence and electroluminescence
Authors: Kim Hong Suk , Cho Min Ju , Jung Kyung Moon , Yu Young‐Jun , Park Young Woo , Jin Jung‐Il , Choi Dong Hoon
Published: December 2007

New light emitting dendrimers were synthesized by reacting 3,5‐bis‐(3,5‐bis‐benzyloxy‐benzyloxy)‐benzoic acid or 3,5‐bis‐[3,5‐bis‐(3,5‐bis‐benzyloxy‐benzyloxy)‐benzyloxy]‐benzoic acid with a carbazolyl vinyl spirobifluorene moiety. A blue‐emitting core dye was encapsulated by multibenzyloxy dendrons, and two dendrimers having different densities of dendrons were prepared. Photoluminescence (PL) studies of the dendrimers demonstrated that at the higher density of benzyloxy dendrons, the featureless vibronic transitions were improved, causing lesser excimer emission. The similarity of the solution and solid emission spectra of the larger dendrimer, 10, revealed the suppression of molecular aggregation in the solid film, which is attributed to the presence of the bulky benzyloxy dendrons. The electroluminescence spectra of multilayered devices made using 10 predominantly exhibited blue emissions; similar emission was observed in the PL spectra of its thin film. The multilayered devices made using 3, 9, and 10 showed luminances of 1021 cd m−2 at 5 V, 916 cd m−2 at 6 V, and 851 cd m−2 at 6.5 V, respectively. The largest dendrimer, 10, bearing a greater number of benzyloxy dendrons, exhibited a blue‐like emission with CIE 1931 chromaticity coordinates of x = 0.16 and y = 0.13, which is due to the influence of a higher shielding effect. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 501–514, 2008
Preparation of MEH‐PPV/nanosized titania hybrids via in situ sol–gel reaction of titanium alkoxide: Optical property
Authors: Chen Hung‐Jen , Wang Leeyih , Chiu Wen‐Yen
Published: December 2007

Homogenously dispersed organic (MEH‐PPV)/inorganic (nanosized titania) hybrids were successfully synthesized. The method of preparation was based on a simple one‐step in situ sol–gel technique using titanium isopropoxide (TIP) as the precursor. The key benefit of this preparation was that TIP interacted with both 2‐chlorophenol and MEH‐PPV, so that the degree of aggregation and phase separation could be kept to a minimum with a suitable recipe. MEH‐PPV/TIP/H2O/2‐chlorophenol of various weight ratios were synthesized to examine the morphology as well as optical properties of the MEH‐PPV/TIP(titania) hybrid. The observation of MEH‐PPV gelation and Fourier transform infrared results verified the interaction existing between MEH‐PPV and TIP. SEM photographs showed that TIP(titania) were homogenously dispersed in the MEH‐PPV film if the hybrid solution was clear from the use of a suitable recipe. UV–vis absorption measurements showed that the addition of TIP decreased the conjugation length of MEH‐PPV. A redshift in the photoluminescence (PL) emission was observed in almost all the hybrids in the solution state, because of the aggregation of MEH‐PPV. However, it was found that spinning destroyed the aggregation of MEH‐PPV, resulting in a blueshift in the PL emission of the hybrids. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 515–529, 2008
Copolymers of 4‐(1‐methyl‐1‐mesityl‐3‐cyclobutyl)‐2‐N‐1, 3‐thiazole‐2‐yl methacrylamide with 2‐[(5‐methylisoxazol‐3‐yl) amino]‐2‐oxo‐ethyl methacrylate: Synthesis, characterization, monomer reactivity ratios and biological activity
Authors: Erol Ibrahim , Dedelioglu Ayşe
Published: December 2007

The free radical copolymerization of 4‐(1‐methyl‐1‐mesityl‐3‐cyclobutyl)‐2‐N‐1, 3‐thiazole‐2‐yl methacrylamide (MCTMA) with 2‐[(5‐methylisoxazol‐3‐yl)amino]‐2‐oxo‐ethyl methacrylate (IAOEMA) has been carried out in 1, 4‐dioxane at 65 °C ± 1 and were analyzed by Fourier transform infrared, 1H NMR, 13C NMR, and gel permeation chromatography. 1H‐NMR analysis was used to determine the molar fractions of MCTMA and IAOEMA in the copolymers. The monomer‐reactivity ratios were calculated according to the general copolymerization equation using Kelen–Tüdõs and Finemann–Ross linearization methods. The reactivity ratios indicated a tendency toward random copolymerization. The polydispersity indices of the polymers, determined with gel permeation chromatography, suggested a strong tendency for chain termination by disproportionation. The thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. The glass‐transition temperature of the copolymers increased with increasing MCTMA content in the copolymers. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Shimadzu TGA 60 thermogravimetric analysis thermobalance. All the products showed moderate activity against different strains of bacteria and fungi. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 530–542, 2008
Development of an immuno tandem mass spectrometry (iMALDI) assay for EGFR diagnosis
Authors: Jiang Jian , Parker Carol E. , Hoadley Katherine A. , Perou Charles M. , Boysen Gunnar , Borchers Christoph H.
Published: December 2007

The epidermal growth factor receptor (EGFR) is highly expressed in a variety of tumors, and is therefore an important biomarker for cancer diagnosis and a target for cancer therapy. We have developed a novel peptide‐based immuno tandem mass spectrometry (iMALDI) diagnostic assay for highly sensitive, highly specific, and quantitative analysis of EGFR, which we have applied to the detection of the EGFR peptide in three cell lines and in a tumor biopsy sample. This assay is capable of detecting the EGFR target peptide bound to the antibody beads at attomole levels. The ability to directly obtain amino acid sequence data by MS/MS on any affinity‐captured peptides provides specificity to this diagnostic technique. This avoids the problem of “false positives” which can result from the nonspecific binding that can occur with any affinity‐based technique. The addition of stable‐labeled versions of the target peptide (synthesized from stable‐isotope coded amino acids) as internal standards allows absolute quantitation of the target protein.
In vitroandin vivoeffects ofRanunculus peltatussubsp.baudotiimethanol extract on models of eicosanoid production and contact dermatitis
Authors: Prieto J. M. , Recio M. C. , Giner R. M. , Schinella G. R. , Máñez S. , Ríos J. L.
Published: December 2007

Ranunculus(Crowfoot) species are numerous and they are all reputed to be counter‐irritants and are used in several topical conditions. In order to study the pharmacological mechanisms of action underlying this popular use, a methanol extract ofRanunculus peltatuswas testedin vitroin various assays involving eicosanoid and human elastase release by intact cells as well asin vivo, with models of delayed‐type hypersensitivity (DTH) contact dermatitis. The extract proved to be a selective inhibitor of the cyclooxygenase‐1 pathway, producing the total inhibition of 12‐(S)‐HHTrE release at 200 µg/mL, while leaving both 5‐lipoxygenase and 12‐lipoxygenase activities unaffected at the same dose. Then‐hexane, chloroform and ethyl acetate fractions of the crude methanol extract inhibited LTB4release by intact rat peritoneal neutrophils, but more polar fractions were inactive and did not increase the 5‐LOX activity as seen previously for extracts of otherRanunculusspecies. In thein vivomodels, the methanol extract reduced the dinitrofluorobenzene (DNFB)‐induced oedema by 40%, but failed to inhibit the oedema brought on by oxazolone. The results agree with the age‐old assertion that Water Crowfoot species can be used as a topical antiinflammatory remedy without the prominent irritant action that accompanies the application of non‐aquaticRanunculusspecies. Copyright © 2007 John Wiley & Sons, Ltd.
Hypoglycemic activity of Ailanthus excelsa leaves in normal and streptozotocin‐induced diabetic rats
Authors: Cabrera W. , Genta S. , Said A. , Farag A. , Rashed K. , Sánchez S.
Published: December 2007

The hypoglycemic activity of a 70% methanol extract from the leaves of Ailanthus excelsa Roxb. (Simaroubaceae) was studied in normal, transiently hyperglycemic and streptozotocin (STZ)‐induced diabetic rats. Oral administration of the extract at doses of 14, 70 and 350 mg/kg body weight caused no significant changes in fasting blood glucose levels of normal rats. In an oral glucose tolerance test, the extract produced a significant decrease in glycemia 90 min after the glucose pulse. Daily administration of A. excelsa extract for 60 days produced a significant hypoglycemic effect in diabetic animals. In addition, this treatment improved the altered renal function observed in diabetic control rats. This study suggests that Ailanthus leaf extract could be potentially useful for post‐prandial hyperglycemia treatment. Copyright © 2007 John Wiley & Sons, Ltd.
Antiviral and immunomodulatory effect of a lyophilized extract of Capparis spinosa L. buds
Authors: Arena A. , Bisignano G. , Pavone B. , Tomaino A. , Bonina F. P. , Saija A. , Cristani M. , D'Arrigo M. , Trombetta D.
Published: December 2007

Herpes simplex virus type 1 (HSV‐1) and herpes simplex virus type 2 (HSV‐2) are common human pathogens that in particular cases can also cause severe problems especially in immunodeficient patients. The present paper reports the antiviral and immunomodulatory properties of a methanolic extract of C. spinosa buds (CAP), rich in flavonoids, including several quercetin and kaempferol glycosides. In particular we have investigated whether the in vitro exposure of human peripheral blood mononuclear cells (PBMCs) to CAP might inhibit the replication of HSV‐2 and modulate the induction kinetics of IL‐12, TNF‐α IFN‐γ. Our findings have shown that CAP treatment interferes with HSV‐2 replication in PBMCs inhibiting the extracellular virus release upregulating their production of IL‐12, IFN‐γ and TNF‐α. One could speculate that CAP may contribute in improving immune surveillance of PBMCs toward virus infection by up‐regulating expression of peculiar proinflammatory cytokines; it should thus be successfully employed for treatment of HSV‐2 infections in immunocompromised hosts.
Simultaneous lipidomic analysis of three families of bioactive lipid mediators leukotrienes, resolvins, protectins and related hydroxy‐fatty acids by liquid chromatography/electrospray ionisation tandem mass spectrometry
Authors: Masoodi Mojgan , Mir Adnan A. , Petasis Nicos A. , Serhan Charles N. , Nicolaou Anna
Published: December 2007

Bioactive lipid mediators derived from polyunsaturated fatty acids (PUFA) exhibit a range of tissue‐ and cell‐specific activities in many physiological and pathological processes. Electrospray ionisation tandem mass spectrometry coupled to liquid chromatography (LC/ESI‐MS/MS) is a sensitive, versatile analytical methodology for the qualitative and quantitative analysis of lipid mediators. Here we present an LC/ESI‐MS/MS assay for the simultaneous analysis of twenty mono‐ and poly‐hydroxy‐fatty acid derivatives of linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acids. The assay was linear over the concentration range 1–100 pg/µL, whilst the limits of detection and quantitation were 10–20 and 20–50 pg, respectively. The recovery of the extraction methodology varied from 76–122% depending on the metabolite. This system is useful for profiling a range of biochemically related potent mediators including the newly discovered resolvins and protectins, and their precursor hydroxyeicosapentaenoic and hydroxydocosahexaenoic acids, and, consequently, advance our understanding of the role of PUFA in health and disease. Copyright © 2007 John Wiley & Sons, Ltd.
Optimization to eliminate the interference of migration isomers for measuring 1‐O‐β‐acyl glucuronide without extensive chromatographic separation
Authors: Xue Y.‐J. , Akinsanya J. Billy , Raghavan Nirmala , Zhang Donglu
Published: December 2007

A highly selected reaction monitoring (SRM) method has been investigated for the determination of muraglitazar 1‐O‐β‐acyl glucuronide in animal and human plasma without chromatographic separation of this naturally formed acyl glucuronide from its migration isomers. In the ion source or the collision cell, glucuronides are often prone to lose the dehydrated glucuronic acid (176 Da) and convert back into the parent drug (aglycone). The extent of loss of the glucuronide moiety can differ among glucuronides. For the naturally occurring muraglitazar 1‐O‐β‐acyl glucuronide, or its synthetic anomer 1‐O‐α‐glucuronide, the loss of the glucuronide moiety was a major fragment ion. The loss of the glucuronide moiety was greater for the 1‐O‐β‐acyl glucuronide than the 1‐O‐α‐anomer. In addition, the loss of the glucuronide moiety was insignificant (less than 0.01%) with the other glucuronide isomers (2‐, 3‐ or 4‐O, α or β). Given the fact that the 1‐O‐α‐anomer was a minor impurity in the muraglitazar 1‐O‐β‐acyl glucuronide reference standard, and not either a conversion product of 1‐O‐β‐acyl glucuronide or endogenously formed, the SRM transition corresponding to the loss of the glucuronide moiety was very specific for 1‐O‐β‐acyl glucuronide, and practically free from interference of the other isomers under optimized collision‐cell conditions. As a result, extensive chromatographic separation of 1‐O‐β‐acyl glucuronide from its migration isomers was not required. The use of this specific SRM transition effectively reduced the separation time from 12.0 min of a long‐column high‐performance liquid chromatography (HPLC) method to 2.5 min by use of a shorter column. The standard curve performance and analysis results of 1‐O‐β‐acyl glucuronide incubation samples showed that the short‐column method could produce equivalent results to the long‐column method but with a 4.5‐fold improvement in sample throughput. This approach may be useful for other 1‐O‐β‐acyl glucuronide measurements with proper tuning of collision energy. The generation of a breakdown curve (abundance vs. collision energy) helps to define whether appropriate conditions may be selected for specific MRM transitions. Copyright © 2007 John Wiley & Sons, Ltd.
Morse theory for indefinite nonlinear elliptic problems
Authors: Chang Kung-Ching , Jiang Mei-Yue
Published: December 2007

Using the heat flow as a deformation, a Morse theory for the solutions of the nonlinear elliptic equation:

−\mathrm{\Delta }u−\lambda u = a_{ + }(x)|u|^{q−1}u−a_{−}(x)|u|^{p−1}u + h(x,u)

in a bounded domain

\Omega \subset \mathbf{R}^{N}

with the Dirichlet boundary condition is established, where

a_{ \pm }⩾0

,

\mathrm{\sup p}(a_{−}) \cap \mathrm{\sup p}(a_{ + }) = \emptyset

,

\mathrm{\sup p}(a_{ + }) \neq \emptyset

,

1 < q < 2^{ \ast }−1

and

p > 1

. Various existence and multiplicity results of solutions are presented.
Existence and uniqueness for a nonlinear parabolic/Hamilton–Jacobi coupled system describing the dynamics of dislocation densities
Authors: Ibrahim Hassan
Published: December 2007

We study a mathematical model describing the dynamics of dislocation densities in crystals. This model is expressed as a 1D system of a parabolic equation and a first order Hamilton–Jacobi equation that are coupled together. We examine an associated Dirichlet boundary value problem. We prove the existence and uniqueness of a viscosity solution among those assuming a lower-bound on their gradient for all time including the initial time. Moreover, we show the existence of a viscosity solution when we have no such restriction on the initial data. We also state a result of existence and uniqueness of entropy solution for the initial value problem of the system obtained by spatial derivation. The uniqueness of this entropy solution holds in the class of bounded-from-below solutions. In order to prove our results on the bounded domain, we use an “extension and restriction” method, and we exploit a relation between scalar conservation laws and Hamilton–Jacobi equations, mainly to get our gradient estimates.

Nous étudions un modèle mathématique décrivant la dynamique de densités de dislocations dans les cristaux. Ce modèle s'écrit comme un système 1D couplant une équation parabolique et une équation de Hamilton–Jacobi du premier ordre. Nous examinons un problème de Dirichlet associé. On montre l'existence et l'unicité d'une solution de viscosité dans la classe des fonctions ayant un gradient minoré pour tout temps ainsi qu'au temps initial. De plus, on montre l'existence d'une solution de viscosité sans cette condition sur la donnée initiale. On présente également un résultat d'existence et d'unicité d'une solution entropique pour le problème d'évolution obtenu par dérivation spatiale. L'unicité de cette solution entropique a lieu dans la classe des solutions minorées. Pour montrer nos résultats sur le domaine borné, on utilise une méthode de « prolongement et restriction », et on profite essentiellement d'une relation entre les lois de conservation scalaire et les équations de Hamilton–Jacobi, pour obtenir des contrôles du gradient.
Regularity of Hölder continuous solutions of the supercritical quasi-geostrophic equation
Authors: Constantin Peter , Wu Jiahong
Published: December 2007

We present a regularity result for weak solutions of the 2D quasi-geostrophic equation with supercritical (

\alpha < 1/ 2

) dissipation

(−\mathrm{\Delta })^{\alpha }

: If a Leray–Hopf weak solution is Hölder continuous

\theta \in C^{\delta }(\mathbb{R}^{2})

with

\delta > 1−2\alpha

on the time interval

[t_{0},t]

, then it is actually a classical solution on

(t_{0},t]

.
A stochastic Lagrangian proof of global existence of the Navier–Stokes equations for flows with small Reynolds number
Authors: Iyer Gautam
Published: December 2007

We consider the incompressible Navier–Stokes equations with spatially periodic boundary conditions. If the Reynolds number is small enough we provide an elementary short proof of the existence of global in time Hölder continuous solutions. Our proof uses a stochastic representation formula to obtain a decay estimate for heat flows in Hölder spaces, and a stochastic Lagrangian formulation of the Navier–Stokes equations.
Functional magnetic resonance imaging of cerebral activation during spinal cord stimulation in failed back surgery syndrome patients
Authors: Stančák Andrej , Kozák Jiří , Vrba Ivan , Tintěra Jaroslav , Vrána Jiří , Poláček Hubert , Stančák Marián
Published: December 2007

Spinal cord stimulation (SCS) consisting of electrical stimulation of the dorsal spinal cord using epidural electrodes has been shown to relieve chronic neuropathic pain. To analyze the cerebral activation patterns related to SCS, and to evaluate the effects of SCS on the processing of acute experimental pain, we performed functional magnetic resonance imaging (fMRI) on eight patients suffering from failed back surgery syndrome who were also being treated with SCS for severe pain in their legs and lower back. Three types of stimulation were used, each lasting 36s: (i) SCS, (ii) heat pain (HP) applied to the leg affected by neuropathic pain, and (iii) simultaneous HP and SCS.

During SCS, we found increased activation of the medial primary sensorimotor cortex somatotopically corresponding to the foot and/or perineal region, contralateral posterior insula, and the ipsilateral secondary somatosensory cortex (S2). Decreased activation was seen in the bilateral primary motor cortices and the ipsilateral primary somatosensory cortex corresponding to the shoulder, elbow and hand. Compared to separately presented HP and SCS, simultaneous HP and SCS showed statistically significant activation of the bilateral inferior temporal cortex and the ipsilateral cerebellar cortex.

The activation of the primary motor cortex, insula and S2 during SCS may directly interfere with the processing of neuropathic pain. When SCS is associated with heat pain, the paralimbic association cortex and cerebellum show activation exceeding the sum of activations resulting from separate SCS and heat pain stimulation. The explanation of this could possibly rest with the continuous comparisons of simultaneous pain and somatosensory sensations occurring in a single dermatome.
Diosgenin, a naturally occurring steroid, suppresses fatty acid synthase expression in HER2‐overexpressing breast cancer cells through modulating Akt, mTOR and JNK phosphorylation
Authors: Chiang Chun-Te , Way Tzong-Der , Tsai Shang-Jie , Lin Jen-Kun
Published: December 2007

Fatty acid synthase (FAS) expression is markedly elevated in HER2‐overexpressing breast cancer cells. In this study, diosgenin, a plant‐derived steroid, was found to be effective in suppressing FAS expression in HER2‐overexpressing breast cancer cells. Diosgenin preferentially inhibited proliferation and induced apoptosis in HER2‐overexpressing cancer cells. Furthermore, diosgenin inhibited the phosphorylation of Akt and mTOR, and enhanced phosphorylation of JNK. The use of pharmacological inhibitors revealed that the modulation of Akt, mTOR and JNK phosphorylation was required for diosgenin‐induced FAS suppression. Finally, we showed that diosgenin could enhance paclitaxel‐induced cytotoxicity in HER2‐overexpressing cancer cells. These results suggested that diosgenin has the potential to advance as chemopreventive or chemotherapeutic agent for cancers that overexpress HER2.
Pyruvate‐sensitive AOX exists as a non‐covalently associated dimer in the homeothermic spadix of the skunk cabbage, Symplocarpus renifolius
Authors: Onda Yoshihiko , Kato Yoshiaki , Abe Yukie , Ito Takanori , Ito-Inaba Yasuko , Morohashi Miyuki , Ito Yuka , Ichikawa Megumi , Matsukawa Kazushige , Otsuka Minoru , Koiwa Hiroyuki , Ito Kikukatsu
Published: December 2007

The cyanide‐resistant alternative oxidase (AOX) is a homodimeric protein whose activity can be regulated by the oxidation/reduction state and by α‐keto acids. To further clarify the role of AOX in the skunk cabbage, Symplocarpus renifolius, we have performed expression and functional analyses of the encoding gene. Among the various tissues in the skunk cabbage, SrAOX transcripts were found to be specifically expressed in the thermogenic spadix. Moreover, our data demonstrate that the SrAOX protein exists as a non‐covalently associated dimer in the thermogenic spadix, and is more sensitive to pyruvate than to other carboxylic acids. Our results suggest that the pyruvate‐mediated modification of SrAOX activity plays a significant role in thermoregulation in the skunk cabbage.
Crystal structure of RVV‐X: An example of evolutionary gain of specificity by ADAM proteinases
Authors: Takeda Soichi , Igarashi Tomoko , Mori Hidezo
Published: December 2007

Russell's viper venom factor X activator (RVV‐X) is a heterotrimeric metalloproteinase with a mammalian ADAM‐like heavy chain and two lectin‐like light chains. The crystal structure of RVV‐X has been determined at 2.9 Å resolution and shows a hook‐spanner‐wrench‐like architecture, in which the metalloproteinase/disintegrin region constitutes a hook, and the lectin‐like domains constitute a handle. A 6.5 nm separation between the catalytic site and a putative exosite suggests a docking model for factor X. The structure provides a typical example of the molecular evolution of multi‐subunit proteins and insights into the molecular basis of target recognition and proteolysis by ADAM/adamalysin/reprolysin proteinases.
Inhibition of SH2‐domain containing inositol phosphatase 2 (SHIP2) in insulin producing INS1E cells improves insulin signal transduction and induces proliferation
Authors: Grempler Rolf , Leicht Stefanie , Kischel Ivonne , Eickelmann Peter , Redemann Norbert
Published: December 2007

Inhibition of the lipid phosphatase SH2‐domain containing inositol phosphatase 2 (SHIP2) in L6‐C10 muscle cells, in 3T3‐L1 adipocytes and in the liver of db/db mice has been shown to ameliorate insulin signal transduction and established SHIP2 as a negative regulator of insulin action. Here we show that SHIP2 inhibition in INS1E insulinoma cells increased Akt, glycogen synthase kinase 3 and extracellular signal‐regulated kinases 1 and 2 phosphorylation. SHIP2 inhibition did not prevent palmitate‐induced apoptosis, but increased cell proliferation. Our data raise the interesting possibility that SHIP2 inhibition exerts proliferative effects in β‐cells and further support the attractiveness of a specific inhibition of SHIP2 for the treatment of type 2 diabetes.
Correlation between cellulose binding and activity of cellulose‐binding domain mutants of Humicola grisea cellobiohydrolase 1
Authors: Takashima Shou , Ohno Mitsuhiro , Hidaka Makoto , Nakamura Akira , Masaki Haruhiko , Uozumi Takeshi
Published: December 2007

The cellulose‐binding domains (CBDs) of fungal cellulases interact with crystalline cellulose through their hydrophobic flat surface formed by three conserved aromatic amino acid residues. To analyze the functional importance of these residues, we constructed CBD mutants of cellobiohydrolase 1 (CBH1) of the thermophilic fungus Humicola grisea, and examined their cellulose‐binding ability and enzymatic activities. High activity on crystalline cellulose correlated with high cellulose‐binding ability and was dependent on the combination and configuration of the three aromatic residues. Tyrosine works best in the middle of the flat surface, while tryptophan is the best residue in the two outer positions.
Acute administration of 3,5‐diiodo‐l‐thyronine to hypothyroid rats affects bioenergetic parameters in rat skeletal muscle mitochondria
Authors: Lombardi Assunta , Lanni Antonia , de Lange Pieter , Silvestri Elena , Grasso Paola , Senese Rosalba , Goglia Fernando , Moreno Maria
Published: December 2007

We investigated the mechanism by which 3,5‐diiodo‐l‐thyronine (T2) affects skeletal muscle mitochondrial bioenergetic parameters following its acute administration to hypothyroid rats. One hour after injection, T2 increased both coupled and uncoupled respiration rates by +27% and +42%, respectively. Top‐down elasticity analysis revealed that these effects were the result of increases in the substrate oxidation and mitochondrial uncoupling. Discriminating between proton‐leak and redox‐slip processes, we identified an increased mitochondrial proton conductance as the “pathway” underlying the effect of T2 on mitochondrial uncoupling. As a whole, these results may provide a mechanism by which T2 rapidly affects energy metabolism in hypothyroid rats.
Self‐reported prevalence of endometriosis and its symptoms among Puerto Rican women
Authors: Flores Idhaliz , Abreu Silkha , Abac Sonia , Fourquet Jessica , Laboy Joaquin , Ríos‐Bedoya Carlos
Published: December 2007

Objective

To determine the prevalence of endometriosis and its symptoms in a Puerto Rican cohort, and to describe the menstrual, obstetric, and clinical profiles of the women.

Methods

A self‐administered questionnaire was given to 1285 Puerto Rican women. Categorical variables were compared using χ2 analysis or Fisher exact test.

Results

There were 57 self‐reported cases of endometriosis (48 surgically confirmed) among 1193 valid questionnaires, for a point prevalence of 4.0%. A diagnosis of endometriosis was significantly associated with dysmenorrhea, dyspareunia, and chronic pelvic pain, but not with menstrual cycle characteristics. Undiagnosed women commonly reported signs and symptoms of endometriosis.

Conclusions

The estimated prevalence of endometriosis in Puerto Rico is 4.0%, comparable to what has been reported in other populations. Endometriosis symptoms were common in the population surveyed, indicating the need for increased awareness and development of public health policies leading to early diagnosis and appropriate management.
Fatty acids, antioxidants, and oxidative stress in pre‐eclampsia
Authors: Mehendale Savita , Kilari Anitha , Dangat Kamini , Taralekar Vaishali , Mahadik Sahebarao , Joshi Sadhana
Published: December 2007

Objective

To investigate whether free radical‐mediated membrane lipid peroxidation may be implicated in the pathogenesis of pre‐eclampsia.

Methods

A prospective study using a sample of 55 healthy pregnant women and 60 pre‐eclamptic women recruited at Bharati Medical Hospital, Pune, India. Maternal and cord samples were examined for (red blood cells and plasma) fatty acid profiles, antioxidants, and oxidative stress levels. Mean values were compared between case and control groups using the t test and Wilcoxon rank test.

Results

Pre‐eclamptic women showed reduced total omega‐3 fatty acids (P < 0.05), increased omega‐6:omega‐3 ratio (P < 0.05), higher oxidative stress (P < 0.05), and lower antioxidant (P < 0.05) levels. Similar trends were also observed in cord samples.

Conclusion

Reduced antioxidants and increased oxidative stress leading to impaired essential polyunsaturated fatty acid levels may be a key factor in the development of pre‐eclampsia.
Prevalence of and attitude toward urinary incontinence in postmenopausal women
Authors: Hsieh Ching‐Hung , Su Tsung‐Hsien , Chang Shao‐Tung , Lin Shu‐Hui , Lee Meng‐Chih , Lee Mei Yu
Published: December 2007

Objective

To investigate the prevalence of urinary incontinence, and the knowledge, attitudes, and practices of Taiwanese women aged 60 years or older.

Method

A nationwide epidemiological study was conducted and a sample of 2410 women was selected. Personal visits to 1517 women were completed.

Results

A total of 485 (29.8%) women reported urinary incontinence; 250 (69.9%) urinary incontinent women experienced symptoms less than once a month. Regarding knowledge, attitudes, and practices, 822 (54.3%) of the women surveyed knew the meaning of urinary incontinence, and 147 (30.3%) with urinary incontinence had visited a doctor. The main reason given for not seeking medical help was shyness.

Conclusion

Although urinary incontinence is a common symptom, it is often not reported to doctors, which leads to undertreatment. From a public health perspective, there is considerable opportunity to improve women's quality of life by increasing health education about urinary incontinence and its treatment.
Culdocele repair in female pelvic organ prolapse
Authors: Cronjé H.S. , de Beer J.A.A.
Published: December 2007

Objectives

To review patients with a culdocele, a wide and deep cul‐de‐sac, and to report the results of treatment by sacrocolpopexy.

Methods

A retrospective review of 117 patients with a culdocele identified by clinical examination and intraoperatively.

Results

The mean age and parity of the patients were 61.4 years and 3.1, respectively. Bladder complaints occurred in 46% of patients and bowel problems in 74% (mainly obstructed defecation). Something protruded through the vaginal introitus in 84% of patients. All patients were treated with a sacrocolpopexy: 96% with mobilization and elevation of the rectum (rectopexy), and 79% with Burch colposuspension. Follow‐up results were obtained for 98% of the patients (mean, 14.7 months). Recurrent prolapse occurred in 10% of patients.

Conclusions

A culdocele differs from an enterocele because it a distended and deep cul‐de‐sac without a true hernia between the distal vagina and rectum. Sacrocolpopexy resulted in a 10% recurrence rate of prolapse.
Reassociated tones and coalescent syllables in Naxi (Tibeto-Burman)
Authors: Michaud Alexis , Xueguang He
Published: December 2007

The Western dialect of Naxi has four lexical tones: High, Mid, Low and Rising; the latter is rare in the lexicon. Rising contours on monosyllables are frequent in connected speech, however, as a result of a process of syllable reduction: reduction of a morpheme carrying the High tone results in re-association of its tone to the syllable that precedes it in the sentence, creating a rising contour. An experiment (with one speaker and five listeners) establishes that there is not only one rising contour that originates in tonal reassociation, as reported in earlier descriptions, but two: Low-to-High and Mid-to-High – as could be expected by analogy with phenomena observed in Niger-Congo languages and elsewhere. A second set of experiments (same speaker; six listeners) investigates the reduction of Mid- and Low-tone syllables: they reduce to [] and [], respectively, and coalesce with the preceding syllable (in Naxi, syllabic structure is simply consonant + glide + vowel). Unlike High-tone syllable reduction, this process stops short of complete tonal de-linking. These experiments aim to provide a complete picture of syllable reduction patterns in Naxi. It is argued that the notions of floating tones and tonal reassociation can be usefully applied to the Naxi data.
Variation and change in thetrapandstrutvowels of RP: a real time comparison of five acoustic data sets
Authors: Fabricius Anne H.
Published: December 2007

The present study examines evidence for change in real time within the short vowel subsystem of the RP accent of English over the course of the twentieth century. It compares plots of average formant positions for the short vowels, stemming from several data corpora. It furthermore describes a change over time in the juxtaposition of thetrapandstrutvowels as captured in the calculated angle and distance between the two, usingtrapas a fixed point. This representation of a relationship in a single measurement by means of angle calculation is a methodological innovation for the sociophonetic enterprise. A value specifying the geometric relationship between two vowel positions is precise and replicable, as well as abstract enough to be comparable across data sets. Differences between ‘phonetic’ and ‘sociolinguistic’ stances on the interpretation of acoustic vowel data in formant plots and the issue of suitable vowel normalisation procedures for sociophonetics will also be discussed.
Remarriage in a pre-transitional Italian community
Authors: BRESCHI MARCO , MANFREDINI MATTEO , FORNASIN ALESSIO
Published: December 2007

The article explores the roles of household compositional factors and socio-economic status on widowhood and remarriage. By using micro-level data from a nineteenth-century Italian community for the period 1819–1859, we found evidence of the very predominant role of household structure in the decision to remarry for both widows and widowers. In particular, the interplay between the presence of a supportive family network and the presence of coresiding children from previous marriages stood out as the key factors. The presence of children aged 12 and under promoted the search for a new bride for widowers, whilst the presence of children of any age, especially young ones, decreased the chances of remarriage for widows.
Uniqueness of spacelike hypersurfaces with constant higher order mean curvature in generalized Robertson–Walker spacetimes
Authors: ALÍAS LUIS J. , COLARES A. GERVASIO
Published: December 2007

In this paper we study the problem of uniqueness for spacelike hypersurfaces with constant higher order mean curvature in generalized Robertson–Walker (GRW) spacetimes. In particular, we consider the following question: under what conditions must a compact spacelike hypersurface with constant higher order mean curvature in a spatially closed GRW spacetime be a spacelike slice? We prove that this happens, essentially, under the so callednull convergence condition. Our approach is based on the use of the Newton transformations (and their associated differential operators) and the Minkowski formulae for spacelike hypersurfaces.
Lehmer's Question, Knots and Surface Dynamics
Authors: SILVER DANIEL S. , WILLIAMS SUSAN G.
Published: December 2007

Lehmer's question is equivalent to one about generalized growth rates of Lefschetz numbers of iterated pseudo-Anosov surface homeomorphisms. One need consider only homeomorphisms that arise as monodromies of fibered knots in lens spacesL(n, 1),n> 0. Lehmer's question for Perron polynomials is equivalent to one about generalized growth rates of words under free group endomorphisms.
There exist conjugate simple braids whose associated permutations are not strongly conjugate
Authors: MANCHÓN P. M. G.
Published: December 2007

If two permutations are strongly conjugate, then their corresponding positive permutation braids (also called simple braids) are conjugate. In this paper we exhibit two conjugate simple braids whose associated permutations are not strongly conjugate. In terms of the grey and black graphs with vertices in the ultra summit set defined in [1], this result can be reformulated by saying that there are ultra summit sets with simple braids (hence with canonical lengthk= 1) in which the grey graph is not connected. Birman, Gebhardt and González Meneses have given similar examples, but withk≥ 2 [1]. Recall that the set of simple braids onnstrings is a basis of the Hecke algebraHn. If two simple braids onnstrings are conjugate, the associated permutations are centrally conjugate, which means that the coefficients of any central element ofHncorresponding to these simple braids are equal. Working on topological dynamics, Hall and Carvalho [8] have discovered two braids on 12 strings (one and its reverse) which are not conjugate. Since one braid is the reverse of the other, their corresponding permutations are centrally conjugate. Forn≤ 6 we checked that central conjugacy implies conjugacy of the corresponding simple braids.
Polynomial bounds for equivalence of quadratic forms with cube-free determinant
Authors: DIETMANN RAINER
Published: December 2007

Given two integrally equivalent integral quadratic forms in at least three variables and with cube-free determinant, we establish an upper bound on the smallest unimodular matrix transforming one of the forms into the other. This bound is polynomial in the height of the two forms involved, confirming a conjecture of Masser for the class of forms considered.
Interactions of particles, adjectival resultatives and benefactive double object constructions in Norwegian
Authors: Tungseth Mai
Published: December 2007

In this paper, I take a closer look at a set of observations concerning word order and co-occurrence restrictions on verb-particle constructions, benefactive double object constructions and resultative constructions in Norwegian. While a particle can co-occur with both a beneficiary DP and a resultative AP, beneficiary DPs and resultatives cannot co-occur at all. I give an analysis in terms of the system proposed in Ramchand (2006), where I argue that the co-occurrence restrictions follow from the syntactic structure assumed together with independent properties of adjectival resultative constructions and verb-particle constructions.
Introduction: perfectivity, telicity and the Nordic languages
Authors: Harley Heidi , Folli Raffaella , Jensen Britta
Published: December 2007

This volume contains articles by Kristín M. Jóhannsdóttir, Ingebjørg Tonne, Mai Tungseth and Anne Tamm on perfectivity and telicity in some of the Nordic languages. In this introduction, we summarise the main claims and conclusions of each paper, and briefly discuss the recurring themes and differences in the analyses proposed in the articles included in this special issue of the Nordic Journal of Linguistics.