bluuebunny/crossref_metadata_2025 huggingface dataset:
On Turing degrees of points in computable topology
Authors: Kalantari Iraj , Welch Larry
Published: August 2008

This paper continues our study of computable point‐free topological spaces and the metamathematical points in them. For us, a point is the intersection of a sequence of basic open sets with compact and nested closures. We call such a sequence a sharp filter. A function fF from points to points is generated by a function F from basic open sets to basic open sets such that sharp filters map to sharp filters. We restrict our study to functions that have at least all computable points in their domains.

We follow Turing's approach in stating that a point is computable if it is the limit of a computable sharp filter; we then define the Turing degree Deg(x) of a general point x in an analogous way. Because of the vagaries of the definition, a result of J. Miller applies and we note that not all points in all our spaces have Turing degrees; but we also show a certain class of points do. We further show that in ℝn all points have Turing degrees and that these degrees are the same as the classical Turing degrees of points defined by other researchers.

We also prove the following: For a point x that has a Turing degree and lies either on a computable tree T or in the domain of a computable function fF, there is a sharp filter on T or in dom(F) converging to x and with the same Turing degree as x. Furthermore, all possible Turing degrees occur among the degrees of such points for a given computable function fF or a complete, computable, binary tree T. For each x ∈ dom(fF) for which x and fF (x) have Turing degrees, Deg(fF (x)) ≤ Deg(x). Finally, the Turing degrees of the sharp filters convergent to a given x are closed upward in the partial order of all Turing degrees. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effective Fine‐convergence of Walsh‐Fourier series
Authors: Mori Takakazu , Yasugi Mariko , Tsujii Yoshiki
Published: August 2008

We define the effective integrability of Fine‐computable functions and effectivize some fundamental limit theorems in the theory of Lebesgue integrals such as the Bounded Convergence Theorem, the Dominated Convergence Theorem, and the Second Mean Value Theorem. It is also proved that the Walsh‐Fourier coefficients of an effectively integrable Fine‐computable function form a Euclidian computable sequence of reals which converges effectively to zero. This property of convergence is the effectivization of the Walsh‐Riemann‐Lebesgue Theorem. The article is closed with the effective version of Dirichlet's test. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monotone numerical schemes for a Dirichlet problem for elliptic operators in divergence form
Authors: Limić Nedžad , Rogina Mladen
Published: August 2008

We consider a second‐order differential operator A(x)=−∑∂iaij(x)∂j+ ∑∂j(bj(x)·)+c(x) on ℝd, on a bounded domain D with Dirichlet boundary conditions on ∂D, under mild assumptions on the coefficients of the diffusion tensor aij. The object is to construct monotone numerical schemes to approximate the solution of the problem A(x)u(x)=µ(x), x∈D, where µ is a positive Radon measure. We start by briefly mentioning questions of existence and uniqueness introducing function spaces needed to prove convergence results. Then, we define non‐standard stencils on grid‐knots that lead to extended discretization schemes by matrices possessing compartmental structure. We proceed to discretization of elliptic operators, starting with constant diffusion tensor and ending with operators in divergence form. Finally, we discuss W‐convergence in detail, and mention convergence in C and L1 spaces. We conclude by a numerical example illustrating the schemes and convergence results. Copyright © 2008 John Wiley & Sons, Ltd.
Prognostic MRI biomarkers of treatment efficacy for retinopathy
Authors: Berkowitz Bruce A. , Roberts Robin
Published: August 2008

There is a pressing need for retina‐specific imaging biomarkers that robustly measure early (subclinical) changes in physiology, are linked to the histopathology responsible for vision loss, and, importantly, predict treatment efficacy. This review focuses on the following four MRI markers that we have developed and applied in preclinical and clinical settings: preretinal vitreous oxygen level (a steady‐state biomarker of inner retinal oxygen tension); leakage of contrast agent into the vitreous (a steady‐state biomarker of blood–retinal barrier permeability surface area product); change in preretinal vitreous oxygen tension during a hyperoxic provocation (a functional biomarker of vascular autoregulation); and retinal uptake of systemically administered manganese during a visual task (a functional biomarker of intraretinal ion regulation). We conclude that functional biomarkers are most promising for prognostic evaluation of treatment efficacy earlier in the course of retinopathy than is currently possible. Copyright © 2008 John Wiley & Sons, Ltd.
Detection and resolution of feature interactions in IP multimedia subsystem
Authors: Gouya Anahita , Crespi Noël
Published: August 2008

The IP Multimedia Subsystem (IMS) enables the delivery of multimedia services through different access networks. 3GPP adopted the Session Initiation Protocol (SIP) as the IMS signalling protocol. However, IMS interaction with these services faces the ‘feature interaction’ problem encountered in traditional telephony networks. This problem occurs as features invoked during a session behave correctly when processed separately from each other, but not when running together. Although much research work has explored managing feature interactions, applying these solutions in IMS remains challenging and further investigation is needed. This paper aims to analyze the feature interaction issue in IMS and to propose a new solution. We defined a SIP‐based algorithm and the associated mechanisms to enhance IMS service invocation. This algorithm is the core of the Service Broker, a new functional entity in charge of managing feature interaction. We validated our proposal through a performance evaluation and prototyped the Service Broker on an open source IMS platform. Copyright © 2008 John Wiley & Sons, Ltd.
Carnivores and their prey in the Wezmeh Cave (Kermanshah, Iran): a Late Pleistocene refuge in the Zagros
Authors: Mashkour M. , Monchot H. , Trinkaus E. , Reyss J.‐L. , Biglari F. , Bailon S. , Heydari S. , Abdi K.
Published: August 2008

Wezmeh Cave is located on the northeastern edge of the Islamabad plain, a high intermontane valley in the western‐central Zagros. In 1999 a disturbed but large faunal assemblage was recovered from this site. The abundant and extremely diverse faunal spectra present at Wezmeh Cave has highlighted the importance of this assemblage. Carnivore remains constitute the bulk of the assemblage; red fox (Vulpes vulpes) has the highest number of identified specimens followed by spotted hyena (Crocuta crocuta), brown bear (Ursus arctos), wolf (Canis lupus), felids (lion, leopard, lynx/caracal and wildcat), mustelids (badger, polecat, marten) and viverrids (mongoose). Artiodactyls (bovid, cervid, suid), equids, rhinoceros (Dicerorhinus sp.) and small animals (Cape hare, porcupine, tortoise, snake, birds) are also present. According to U‐series dating, the site was occupied from around 70 ka BP through to sub‐recent periods by carnivores. Amongst this rich assemblage, a human fossil tooth was also found and dated by non‐invasive spectrometry gamma dating to 20–25 ka BP. A preliminary zooarchaeological and taphonomic study shows that Wezmeh Cave was used by multiple carnivore species, a unique phenomenon in the Zagros Mountains in particular and southwest Asia in general. Copyright © 2008 John Wiley & Sons, Ltd.
Die kurze Geschichte der Proteinkinase‐Inhibitoren. Jung, kompetitiv, erfolgreich
Authors: Kunick Conrad , Egert‐Schmidt Anne‐Marie
Published: August 2008

Obwohl Proteinkinasen vielfältig an pathophysiologischen Vorgängen beteiligt sind, wurde die Option, durch eine Hemmung dieser Enzyme therapeutisch einzugreifen, lange unterschätzt. In der Grundlagenforschung wurden Anfang der 1980er Jahre bahnbrechende Erkenntnisse zur Struktur, Funktion und Bedeutung der Proteinkinasen gewonnen. Viele der forschenden Pharmaunternehmen machten daraufhin die Suche nach Proteinkinase‐Inhibitoren zu einem Forschungsschwerpunkt.
Protein‐Tyrosinkinasen als Wirkstoff‐Targets. Eine wichtige Gruppe intrazellulärer Regulatoren
Authors: Winckler Thomas , Zündorf Ilse , Dingermann Theo
Published: August 2008

Protein‐Tyrosinkinasen sind wichtige Regulatoren von Signalwegen, die unter anderem die Proliferation von Zellen beeinflussen. Deshalb sind diese Kinasen wichtige Ziele für die Entwicklung von Wirkstoffen gegen Tumorerkrankungen und chronische Entzündungen.
Enzymersatztherapie bei Morbus Gaucher
Authors: Winckler Thomas
Published: August 2008

Rekombinant hergestellte Glucocerebrosidase (Imiglucerase, Cerezyme®) zur Therapie der lysosomalen Speicherkrankheit Morbus Gaucher ist eine der teuersten Medikationen überhaupt. Rekombinante Glucocerebrosidase aus Pflanzenzellen könnte zukünftig helfen, die Therapiekosten zu senken.
A validated reverse‐phase HPLC analytical method for the quantification of phenolic compounds in Baccharis dracunculifolia
Authors: de Sousa João Paulo B. , da Silva Filho Ademar A. , Bueno Paula C. P. , Gregório Luiz E. , Furtado Niege A. J. C. , Jorge Renata F. , Bastos Jairo K.
Published: August 2008

Introduction

Baccharis dracunculifolia, which has great potential for the development of new phytotherapeutic medicines, is the most important botanical source of the southeastern Brazilian propolis, known as green propolis on account of its color.

Objective

To develop a reliable reverse‐phase HPLC chromatographic method for the analysis of phenolic compounds in both B. dracunculifolia raw material and its hydroalcoholic extracts.

Methodology

The method utilised a C18 CLC‐ODS (M) (4.6 × 250 mm) column with nonlinear gradient elution and UV detection at 280 nm. A procedure for the extraction of phenolic compounds using aqueous ethanol 90%, with the addition of veratraldehyde as the internal standard, was developed allowing the quantification of 10 compounds: caffeic acid, coumaric acid, ferulic acid, cinnamic acid, aromadendrin‐4′‐methyl ether, isosakuranetin, drupanin, artepillin C, baccharin and 2,2‐dimethyl‐6‐carboxyethenyl‐2H‐1‐benzopyran acid.

Results

The developed method gave a good detection response with linearity in the range 20.83–800 µg/mL and recovery in the range 81.25–93.20%, allowing the quantification of the analysed standards.

Conclusion

The method presented good results for the following parameters: selectivity, linearity, accuracy, precision, robustness, as well as limit of detection and limit of quantitation. Therefore, this method could be considered as an analytical tool for the quality control of B. dracunculifolia raw material and its products in both cosmetic and pharmaceutical companies. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of desiccation‐induced candidate phosphoproteins from Craterostigma plantagineum isolated with a modified metal oxide affinity chromatography procedure
Authors: Röhrig Horst , Colby Tom , Schmidt Jürgen , Harzen Anne , Facchinelli Fabio , Bartels Dorothea
Published: August 2008

Reversible protein phosphorylation/dephosphorylation is crucial for regulation of many cellular events, and increasing evidence indicates that this post‐translational modification is also involved in the complex process of acquisition of desiccation tolerance. To analyze the phosphoproteome of the desiccation tolerant resurrection plant Craterostigma plantagineum, MOAC‐enriched proteins from leaves at different stages of a de‐/rehydration cycle were separated by 2‐D PAGE and detected by phosphoprotein‐specific staining. Using this strategy 20 putative phosphoproteins were identified by MALDI‐TOF MS and MS/MS, which were not detected when total proteins were analyzed. The characterized desiccation‐related phosphoproteins CDeT11‐24 and CDeT6‐19 were used as internal markers to validate the specificity of the analyses. For 16 of the identified proteins published evidence suggests that they are phosphoproteins. Comparative analysis of the 2‐D gels showed that spot intensities of most identified putative phosphoproteins change during the de‐/rehydration cycle. This suggests an involvement of these proteins in desiccation tolerance. Nearly all changes in the phosphoproteome of C. plantagineum, which are triggered by dehydration, are reversed within 4 days of rehydration, which is in agreement with physiological observations. Possible functions of selected proteins are discussed in the context of the de‐/rehydration cycle.
Translation initiation proteins, ubiquitin–proteasome system related proteins, and 14‐3‐3 proteins as response proteins in FL cells exposed to anti‐benzo[a]pyrene‐7,8‐dihydrodiol‐9,10‐epoxide
Authors: Shen Wenyan , liu Hui , Yu Yingnian
Published: August 2008

Benzo[a]pyrene (B[a]P) is an ubiquitous environmental carcinogen produced during incomplete combustion of organic substances. Anti‐benzo[a]pyrene‐7,8‐dihydrodiol‐9,10‐epoxide (BPDE), is the most carcinogenic form of the ultimate metabolites of B[a]P. The goal of this study was to investigate the responses of human amniotic epithelial FL cells to BPDE at different time intervals after exposure and to find potential biomarkers involved in these responses. Cells were treated with 0.05 μM BPDE for 2 h and incubated for another 3, 12, and 24 h to obtain protein extracts which were resolved by 2‐DE and visualized by silver staining. Sixty‐four spots were up‐regulated while 66 were down‐regulated following BPDE exposure. These altered spots were excised from the gels and analyzed by MALDI‐TOF‐MS. The analysis led to the identification of 84 proteins affected by BPDE. These proteins were involved in regulation of transcription, cell cycle, apoptosis, transport, signal transduction, metabolism,and so forth. Among them, subunits of eukaryotic translation initiation factor 3 (EIF3) including EIF3S2, EIF3S3, EIF3S12, and EIF5A, component proteins of ubiquitin–proteasome system (ubiquitin carboxyl‐terminal esterase L3, proteasome beta 4 subunit, and proteasome beta 3 subunit) and 14‐3‐3 proteins (14‐3‐3 zeta and epsilon) have not been previously associated with a response to BPDE exposure. All these results aid our understanding of the mechanism of BPDE induced cell defensive responses and hazardous effects as well as providing the possibility of the establishment of potential biomarkers.
Polycondensation of trialkoxysilane monomers accelerated by neighboring group participation of urea moiety
Authors: Eguchi Tetsuya , Sudo Atsushi , Endo Takeshi
Published: August 2008

(Phenylaminomethyl)trimethoxysilane (= α‐amino‐siloxane) was treated with various isocyanates to obtain a series of siloxanes having urea moieties (= α‐urea‐siloxanes). Their hydrolysis‐condensation reactions were monitored with 29Si NMR, to reveal that they exhibited much higher reactivity than a urea‐siloxane derived from [3‐(phenylamino)propyl]trimethoxysilane (= γ‐amino‐siloxane). When compared with the derivation of the γ‐amino‐siloxane into the corresponding γ‐urea‐siloxane, those of the α‐amino‐siloxane into the corresponding α‐urea‐siloxanes were accompanied by much larger shifts of the 29Si NMR signal toward a higher magnetic field. These results suggested that the location of the urea moiety in the α‐urea‐siloxanes was favorable to its intramolecular coordination to the silicon atom to exhibit its “neighboring group participation” that promoted transformation of the tetravalent silicon center into the pentavalent one, which is more electrophilic to make the siloxanes more susceptive to undergo the hydrolysis and condensation reactions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6654–6659, 2008
Photochromic LC copolymers containing azobenzene and crown‐ether groups
Authors: Shibaev Valery , Medvedev Alexey , Bobrovsky Alexey
Published: August 2008

An approach for the creation of a novel family of multifunctional crown‐ether‐containing comb‐shaped copolyacrylates consisting of chromophoric (azobenzene), ionophoric (crown‐ether), and mesogenic groups in the same macromolecule was developed. Phase behavior of the copolymers was studied, and correlation between their molecular structure and thermal properties was established. The increase of crown‐ether‐containing groups' concentration up to 26 mol % leads to disruption of nematic order and formation of amorphous phase. Influence of copolymers complexation with potassium perchlorate on mesomorphic properties of such systems was investigated. It was shown that complexation leads to decrease in mesophase thermostability due to the significant reducing of the side group anisometry by perchlorate counter ion. The comparative investigations of photooptical properties and photoorientation processes of copolymers and their complexes were also performed. An essential difference in kinetics of photooptical behavior was revealed; the bulky crown‐ether substituents decrease rotational mobility and prevent photoorientation process of azobenzene fragments diminishing photoinduced orientation and order parameter. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6532–6541, 2008
Influence of the isomeric structures of butyl acrylate on its 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 , Gil M. H.
Published: August 2008

The aim of this work is to the study the influence of the isomer structures of butyl acrylate monomer on the single‐electron transfer/degenerative chain transfer mediated living radical polymerization (SET‐DTLRP). The kinetic of isobutyl acrylate is determined for the first time by SET‐DTLRP in water catalyzed by sodium dithionite. The plots of number‐average molecular weight versus conversion and ln([M]0/[M]) versus time are linear, demonstrating a controlled polymerization. The influence of the isomer t‐butyl, i‐butyl, and n‐butyl on the kinetics, properties, and stereochemistry of the reactions was assessed. To the best of our knowledge, there is no previous report dealing with the synthesis of PiBA by any LRP approach in aqueous medium. The results presented in this work suggest that the stability provided by the acrylate side group has an important influence in the polymerization process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6542–6551, 2008
Electron beam curing with glycerol methacrylate
Authors: Langhals Heinz , Oginski Beata
Published: August 2008

Glycerol methacrylate and hydroxyethyl methacrylate in combination with glycerol dimethacrylate as crosslinker were applied with electron beam irradiation to consolidate the color painting of the terracotta army of the first Chinese Emperor Qin Shihuangdi. The described mixture allowed reducing the necessary irradiation dose for consolidation to 40 kGy. The formation of glossy spots could be suppressed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6660–6663, 2008
Anionic polymerization of 1,3‐cyclohexadiene with alkyllithium/amine system in an aromatic hydrocarbon solvent: Predominant formation of 1,2‐addition product
Authors: Natori Itaru , Natori Shizue
Published: August 2008

Steric hindrance of the amine strongly affected the formation of the dominant 1,2‐addition product from the anionic polymerization of 1,3‐cyclohexadiene (1,3‐CHD) initiated by the alkyllithium (RLi)/amine system in an aromatic hydrocarbon solvent. 1,2‐Cyclohexadiene (1,2‐CHD)/1,4‐cyclohexadiene (1,4‐CHD) unit molar ratios from 85/15 to 93/7 were obtained using an RLi/N,N,N′,N′‐tetramethylethylenediamine (TMEDA) system in toluene. The CLi bonds of poly(1,3‐cyclohexadienyl)lithium (PCHDLi)/TMEDA complex in toluene appeared to be strongly polarized with small steric hindrance. Intermolecular forces contributing to the aggregation were strong for high‐molecular‐weight poly(1,3‐cyclohexadiene) (PCHD) consisting of almost all 1,2‐CHD units. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6604–6611, 2008
Influence of n‐dodecyl mercaptan as chain transfer agent in dispersion polymerization of styrene
Authors: Lee Ki‐Chang , Wi Han‐Ah
Published: August 2008

Dispersion polymerization of styrene with n‐dodecyl mercaptans (DDM) as the chain transfer agent was investigated. PS particles with various molecular weight, molecular weight distribution (MWD), and particle diameter were prepared by varying the concentration of DDM and also the addition time of DDM before and after the particle nucleation. The average particle diameter was increased, whereas polymerization rate, molecular weight, and MWD were decreased with increasing DDM concentrations from 0 to 10 wt %. The effect of addition of DDM before and after particle nucleation was studied at 0.4, 0.8, and 1.0 wt % DDM. The addition of DDM before particle nucleation produced PS particles of relatively large particle diameter and low molecular weight when compared with the addition of DDM after particle nucleation. This study shows that particle nucleation occurs in about 5–6 min, which corresponds to the 15–16% conversion, 372–378 nm in Dn, and provides a facile way to control the particle size and interesting information about the particle formation using the delayed addition of DDM. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6612–6620, 2008
Synthesis of ABCD 4‐miktoarm star polymers by combination of RAFT, ROP, and “Click Chemistry”
Authors: Yang Liping , Zhou Huaxing , Shi Gangyin , Wang Yang , Pan Cai‐Yuan
Published: August 2008

The ABCD 4‐miktoarm star polymers based on polystyrene (PS), poly(ε‐caprolactone) (PCL), poly(methyl acrylate) (PMA), and poly(ethylene oxide) (PEO) were synthesized and characterized successfully. Using the mechanism transformation strategy, PS with three different functional groups (i.e., hydroxyl, alkyne, and trithiocarbonate), PS‐HEPPA‐SC(S)SC12H25, was synthesized by the reaction of the trithiocarbonate‐terminated PS with 2‐hydroxyethyl‐3‐(4‐(prop‐2‐ynyloxy)phenyl) acrylate (HEPPA) in tetrahydrofuran (THF) solution. Subsequently, the ring‐opening polymerization (ROP) of ε‐caprolactone (CL) was carried out in the presence of stannous(II) 2‐ethylhexanoate and PS‐HEPPA‐SC(S)SC12H25, and then the PS‐HEPPA(PCL)‐SC(S)SC12H25 obtained was used in reversible addition‐fragmentation chain transfer (RAFT) polymerization of methyl acrylate (MA) to produce the ABC 3‐miktoarm star polymer, S(PS)(PCL)(PMA) carrying an alkyne group. The ABCD 4‐miktoarm star polymer, S(PS)(PCL)(PMA)(PEO) was successfully prepared by click reaction of the alkyne group on the HEPPA unit with azide‐terminated PEO (PEO‐N3). The target polymer and intermediates were characterized by NMR, FTIR, GPC, and DSC. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6641–6653, 2008
Enhancing dispersion of copper nanowires in melt‐mixed polystyrene composites
Authors: Gelves Genaro A. , Lin Bin , Haber Joel A. , Sundararaj Uttandaraman
Published: August 2008

Copper nanowire (CuNWs)/polystyrene (PS) composites were prepared by melt mixing using unfunctionalized and functionalized nanowires. Alkanethiols were utilized to modify the surface of CuNWs postsynthesis and enable their dispersion in a polymer melt. Unfunctionalized nanowires decreased the electrical resistivity of PS by nine orders of magnitude with 2.0 vol % Cu, and resulted in composites with a viscoelastic behavior dominated by polymer–polymer networks indicating that electrical percolation occurred without a transition from liquid‐like to solid‐like behavior (i.e., rheological percolation). Results from transmission electron microscopy (TEM), scanning electron microscopy (SEM), and melt rheology characterization indicated that surface modification of CuNWs contributed to the dispersion of the nanofiller in the polymer matrix. CuNWs functionalized with 1‐octanethiol and 1‐butanethiol produced rheological percolation and a gradual decrease in the electrical resistivity of the PS nanocomposites with increasing concentration of nanowires. Polymer nanocomposites with low concentrations of functionalized nanowires showed lower complex viscosities than pure PS; this was attributed to a plasticizing effect introduced by the alkanethiols. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2064–2078, 2008
Control of the microstructure of polymer network and effects of the microstructures on light scattering properties of UV‐cured polymer‐dispersed liquid crystal films
Authors: Li Wenbo , Cao Hui , Kashima Miki , Liu Fang , Cheng Zihui , Yang Zhou , Zhu Siquan , Yang Huai
Published: August 2008

Polymer‐dispersed liquid crystals (PDLC) films were prepared from ultraviolet (UV) irradiation‐induced polymerization of the photopolymerizable monomers in photopolymerizable monomers/nematic liquid crystal (LC) mixtures. The effects of the composition of the mixtures, the curing temperature, and the UV light intensity on the microstructure of the polymer network in the PDLC films were investigated. Furthermore, the effects of the microstructures on the light scattering properties of the PDLC films in the wavelength region of 300–2500 nm were studied experimentally and theoretically based on the combination of three kinds of classical light scattering theories: the Rayleigh‐Gans (RG) approach, the anomalous diffraction (AD) approach, and the geometrical optics (GO) approach. It was found that the sizes of LC domain in PDLC films increased with the increase of the LC content as well as the decrease of the UV curing intensity, while increased at first and then decreased with the increase of the curing temperature. Moreover, smaller LC domain sizes could exhibit strong scattering properties in a smaller VIS wavelength region and the transmittance in NIR region (especially in the wavelength range of 1300–2500 nm) obviously decreased with the increasing sizes of LC domain. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2090–2099, 2008
Glass transition and its characteristic length for thin crosslinked polystyrene shells of rodlike capsules
Authors: Sasaki Takashi , Misu Manabu , Shimada Takayuki , Teramoto Mitsuhiro
Published: August 2008

Rodlike capsules consisting of a calcium carbonate core and a crosslinked polystyrene shell were synthesized, and the glass transition temperature (Tg) and characteristic length of the glass transition ξ(Tg) for the thin outer shells were investigated by temperature‐modulated differential scanning calorimetry. The shell thickness ranged from 20 to 129 nm. The ratio of the Tg for the outer shell to the bulk Tg increases with decreasing shell thickness d. The d‐dependence of Tg is interpreted in terms of a simple two‐layer model which assumes that an immobile layer exists near the core‐shell interface. Shells of hollow capsules unexpectedly exhibit a similar d‐dependence of Tg to that for the filled capsules. This is characteristic of the crosslinked polymeric shells, and is attributed to certain spatial heterogeneity of crosslink distribution, and/or to the unstable configuration in the ultrathin shell that does not undergo relaxation due to the crosslink. The latter idea is based on the assumption that unstable configurational state is responsible for the Tg shift from the bulk value observed for nanosized polymeric materials. The ratio of the characteristic length for the shell of the filled capsule to that of the bulk ξf(Tg)/ξb(Tg) decreases with decreasing d. The results are interpreted in terms of the configurational entropy, and it is also suggested that the configurational state of network polymer chains in the shell affects the characteristic length. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2116–2125, 2008
Initial stage of fiber structure development in the continuous drawing of poly(ethylene terephthalate)
Authors: Yamaguchi Takayoshi , Kim Kyounghou , Murata Takahisa , Koide Mitsuharu , Hitoosa Shuuji , Urakawa Hiroshi , Ohkoshi Yutaka , Gotoh Yasuo , Nagura Masanobu , Kotera Masaru , Kajiwara Kanji
Published: August 2008

The initial stage of fiber structure development in the continuous neck‐drawing of amorphous poly(ethylene terephthalate) fibers was analyzed by in situ wide‐angle X‐ray diffraction, small‐angle X‐ray scattering, and fiber temperature measurements. The time error of the measurements (<600 μs) was obtained by synchrotron X‐ray source and laser irradiation heating. A highly ordered fibrillar‐shaped two‐dimensional (smectic‐like) structure was found to be formed less than 1 ms after necking. By analyzing its (001′) and (002′) diffractions, the length of the structure 60–70 nm were obtained. A three‐dimensionally ordered triclinic crystal began to form with the vanishing of the structure around 1 ms after necking. The amount and size of the crystal were almost saturated within several milliseconds of necking, during which time a mainly exothermic heat of crystallization was also observed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2126–2142, 2008
Thiocarbamate‐linked peptides by chemoselective peptide ligation
Authors: Besret Soizic , Ollivier Nathalie , Blanpain Annick , Melnyk Oleg
Published: August 2008

Peptide chemical ligation chemistries, which allow the chemoselective coupling of unprotected peptide fragments, are useful tools for synthesizing native polypeptides or unnatural peptide‐based macromolecules. We show here that the phenylthiocarbonyl group can be easily introduced into peptides on α or ε amino groups using phenylthiochloroformate and standard solid‐phase method. It reacts chemoselectively with cysteinyl peptides to give an alkylthiocarbamate bond. S,N‐shift of the alkylaminocarbonyl group from the Cys side chain to the α‐amino group did not occur. The method was used for linking two peptide chains through their N‐termini, for the synthesis of a cyclic peptide or for the synthesis of di‐ or tetravalent multiple antigenic peptides (MAPs). Thiocarbamate ligation is thus complementary to thioether, thioester or disulfide ligation methods. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Inhibition of soluble epoxide hydrolase by extracts derived from inflammation‐treating Chinese medicinal herbs
Authors: Shi Da‐Hua , Xu Chen , Guo Bin‐Xin , Wang Xiao‐Ting , Chen Yun‐Xi , Tan Ren‐Xiang
Published: August 2008

Soluble epoxide hydrolase (sEH) has been proved to be a key enzyme involved in inflammation progression, and inhibition of sEH is therefore very helpful or crucial for the treatment of inflammation‐related diseases. In order to uncover new clues suggesting the presence of phytochemical‐based sEH inhibitors, and to rationalize the utility of the inflammation‐treating Chinese medicinal herbs, the ethanol extracts derived from 46 medicinal herbs, traditionally used for the treatment of inflammation‐associated diseases in China, were tested for sEH‐inhibition activity using a recently developed sensitive fluorescence‐based assay. Screened at 10 µg/mL, four extracts showed substantial inhibitions of sEH (inhibition rates >50%). The ethanol extract of Sophora flavescens root (Fabaceae) possessed the strongest inhibitory activity against sEH (IC50: 2.07 µg/mL). These preliminary findings highlighted the presence of sEH inhibitor(s) in the plant kingdom, and the possibility that the inflammation‐treating herbal medicines could be an untapped reservoir for sEH‐inhibition agents. Copyright © 2008 John Wiley & Sons, Ltd.
The effect of the aqueous extract of the roots of Asparagus racemosus on hepatocarcinogenesis initiated by diethylnitrosamine
Authors: Agrawal Alka , Sharma Meenakshi , Rai Santosh Kumar , Singh Bharat , Tiwari Manisha , Chandra Ramesh
Published: August 2008

Histopathological studies of the hepatic tissues of Wistar rats treated with diethylnitrosamine (DEN) (200 mg/kg b wt, i.p.) once a week for 2 weeks, followed by treatment with DDT, a tumor promoter (0.05% in diet) for 2 weeks and kept under observation for another 18 weeks, demonstrated the development of malignancy. Pretreatment of Wistar rats with the aqueous extract of the roots of Asparagus racemosus prevented the incidence of hepatocarcinogenesis. Immunohistochemical staining of the hepatic tissues of rats treated with DEN showed the presence of p53+ foci (clusters of cells expressing the mutated p53 protein), whereas an absence of p53+ foci was observed in Wistar rats pretreated with the aqueous extract of the roots of Asparagus racemosus. The microsections of the hepatic tissue of rats treated with DEN followed by treatment with the aqueous extract of Asparagus racemosus showed an absence of p53+ foci. The results of the biochemical determinations also show that pretreatment of Wistar rats with the aqueous extract of Asparagus racemosus leads to the amelioration of oxidative stress and hepatotoxicity brought about by treatment with DEN. These results prove that the aqueous extract of the roots of Asparagus racemosus has the potential to act as an effective formulation to prevent hepatocarcinogenesis induced by treatment with DEN. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of Terminalia arjuna extract on adriamycin‐induced DNA damage
Authors: Reddy Tiyyagura Koti , Seshadri Prabhu , Reddy K. Kodanda Rami , Jagetia G. C. , Reddy C. Damodar
Published: August 2008

The effect of a bark extract of Terminalia arjuna (TAE) was studied on the alteration of adriamycin (ADR)‐induced micronuclei formation in cultured human peripheral blood lymphocytes. Exposure of lymphocytes to ADR resulted in a dose‐dependent increase in the micronuclei formation indicating DNA damage. Pretreatment of lymphocytes with TAE before ADR treatment resulted in a significant decline in micronuclei formation. Increasing doses of ADR caused a dose‐dependent increase in the frequency of lymphocytes bearing one, two and multiple micronuclei. Prior exposure of lymphocytes to 15 µg/mL of TAE significantly reduced the frequency of lymphocytes bearing one, two and multiple micronuclei when compared with ADR‐treated control. TAE‐inhibited the induction of •OH (hydroxyl), O2•− (superoxide), DPPH (1,1‐diphenyl‐2‐picrylhydrazyl), ABTS•+ (2,2‐azino‐bis‐3‐ethyl benzothiazoline‐6‐sulphonic acid) radicals in a dose‐dependent manner. These results demonstrate that TAE protects DNA against ADR‐induced damage. Copyright © 2008 John Wiley & Sons, Ltd.
Antioxidant activity of flavonoids in isolated mitochondria
Authors: Dorta Daniel J. , Pigoso Acácio A. , Mingatto Fábio E. , Rodrigues Tiago , Pestana Cezar R. , Uyemura Sérgio A. , Santos Antonio C. , Curti Carlos
Published: August 2008

Mitochondria are important intracellular sources and targets of reactive oxygen species (ROS), while flavonoids, a large group of secondary plant metabolites, are important antioxidants. Following our previous study on the energetics of mitochondria exposed to the flavonoids quercetin, taxifolin, catechin and galangin, the present work addressed the antioxidant activity of these compounds (1–50 µmol/L) on Fe2+/citrate‐mediated membrane lipid peroxidation (LPO) in isolated rat liver mitochondria, running in parallel studies of their antioxidant activity in non‐organelle systems. Only quercetin inhibited the respiratory chain of mitochondria and only galangin caused uncoupling. Quercetin and galangin were far more potent than taxifolin and catechin in affording protection against LPO (IC50= 1.23 ± 0.27 and 2.39 ± 0.79 µmol/L, respectively), although only quercetin was an effective scavenger of both 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and superoxide radicals. These results, together with the previous study, suggest that the 2,3‐double bond in conjugation with the 4‐oxo function in the flavonoid structure are major determinants of the antioxidant activity of flavonoids in mitochondria, the presence of ano‐di‐OH structure on the B‐ring, as occurs in quercetin, favours this activity via superoxide scavenging, while the absence of this structural feature in galangin, favours it via a decrease in membrane fluidity and/or mitochondrial uncoupling. Copyright © 2008 John Wiley & Sons, Ltd.
Antibacterial potential of Antarctic lichens against human pathogenic Gram‐positive bacteria
Authors: Paudel Babita , Bhattarai Hari Datta , Lee Jin Sung , Hong Soon Gyu , Shin Hyun Woung , Yim Joung Han
Published: August 2008

Extracts from five Antarctic lichens (L3, Stereocaulon alpinum; L5, Ramalina terebrata; L6, Caloplaca sp.; L8, Lecanora sp.; and L17, Caloplaca regalis) were tested for antimicrobial activities against several clinically important microbes by disk diffusion. The minimum inhibitory concentration (MIC) of each extract was determined by a broth dilution method. Extracts from L3, L5, L6 and L8 were active against two Gram(+) strains. B. subtilis was more sensitive to lichen extracts (except L5) than S. aureus. The MIC of lichen extracts against B. subtilis and S. aureus was observed from 36.7 ± 0.3 to 953.8 ± 85.8 µg/mL and 68.5 ± 0.6 to >1000 µg/mL, respectively. Comparisons of MIC values of Antarctic lichen crude extracts to previously published MIC values of some reported lichen metabolites against Gram(+) bacteria indicated that Antarctic lichens might be an enriched source of effective antibacterial agents against clinically relevant Gram(+) species. Copyright © 2008 John Wiley & Sons, Ltd.
Food supplementation with an olive (Olea europaea L.) leaf extract reduces blood pressure in borderline hypertensive monozygotic twins
Authors: Perrinjaquet‐Moccetti Tania , Busjahn Andreas , Schmidlin Caesar , Schmidt Annette , Bradl Barbara , Aydogan Cem
Published: August 2008

Hypertension is a harmful disease factor that develops unnoticed over time. The treatment of hypertension is aimed at an early diagnosis followed by adequate lifestyle changes rather than pharmacological treatment. The olive leaf extract EFLA®943, having antihypertensive actions in rats, was tested as a food supplement in an open study including 40 borderline hypertensive monozygotic twins. Twins of each pair were assigned to different groups receiving 500 or 1000 mg/day EFLA®943 for 8 weeks, or advice on a favourable lifestyle. Body weight, heart rate, blood pressure, glucose and lipids were measured fortnightly. Blood pressure changed significantly within pairs, depending on the dose, with mean systolic differences of ≤6 mmHg (500 mg vs control) and ≤13 mmHg (1000 vs 500 mg), and diastolic differences of ≤5 mmHg. After 8 weeks, mean blood pressure remained unchanged from baseline in controls (systolic/diastolic: 133 ± 5/77 ± 6 vs 135 ± 11/80 ± 7 mmHg) and the low‐dose group (136 ± 7/77 ± 7 vs 133 ± 10/76 ± 7), but had significantly decreased for the high dose group (137 ± 10/80 ± 10 vs 126 ± 9/76 ± 6). Cholesterol levels decreased for all treatments with significant dose‐dependent within‐pair differences for LDL‐cholesterol. None of the other parameters showed significant changes or consistent trends. Concluding, the study confirmed the antihypertensive and cholesterol‐lowering action of EFLA®943 in humans. Copyright © 2008 John Wiley & Sons, Ltd.
Gas‐phase proton‐transfer pathways in protonated histidylglycine
Authors: MacDonald Brandon I. , Thachuk Mark
Published: August 2008

Pathways for proton transfer in the histidylglycine cation are examined in the gas‐phase environment with the goal of understanding the mechanism by which protons may become mobile in proteins with basic amino acid residues. An extensive search of the potential energy surface is performed using density functional theory (DFT) methods. After corrections for zero‐point energy are included, it is found that all the lowest energy barriers for proton transfer between the N‐terminus and the imidazole ring have heights of only a few kcal/mol, while those between the imidazole ring and the backbone amide oxygen have heights of approximately 15 kcal/mol when the proton is moving from the ring to the backbone and only a few kcal/mol when moving from the backbone to the imidazole ring. In mass spectrometric techniques employing collision‐induced dissociation to dissociate protein complex ions or to fragment peptides, these barriers can be overcome, and the protons mobilized. Copyright © 2008 John Wiley & Sons, Ltd.
Oncogenesis by retroviruses: old and new paradigms
Authors: Maeda Naoyoshi , Fan Hung , Yoshikai Yasunobu
Published: August 2008

Retroviruses are associated with a variety of diseases including an array of malignancies, immunodeficiencies and neurological disorders. In particular, studies of oncogenic retroviruses established fundamental principles of modern molecular cancer biology. Studies of avian Rous sarcoma virus (RSV) led to the discovery of the viral oncogene src, and this was followed by the discovery of other viral oncogenes in retroviruses of mammals including rodents, cats, monkeys and so forth. Studies of the viral oncogenes in turn led to the discovery of cellular proto‐oncogenes in the host genome; cellular oncogenes have been shown to be activated in a variety of human cancers, including those with no viral involvement. Oncogenic animal retroviruses can be divided into two groups based on their mechanisms of tumourigenesis, acute transforming retroviruses and nonacute retroviruses. Acute transforming retroviruses are typically replication defective and they induce tumours rapidly due to expression of their viral oncogenes. Nonacute retroviruses are replication competent and they induce tumours with longer latencies, by activating cellular proto‐oncogenes in the tumour cells; this results from insertion of proviral DNA in the vicinity of the activated proto‐oncogene. More recently, human T‐cell leukaemia virus type I (HTLV‐I) was discovered as an etiological agent of human cancer (adult T‐cell leukaemia [ATL]); this virus also encodes regulatory genes some of which are important for its oncogenic potential. Most recently, the retroviral structural protein Envelope (Env) has been shown to be directly involved in oncogenic transformation for certain retroviruses. Env‐induced transformation is a new paradigm for retroviral oncogenesis. In this review, we will summarise research on retrovirus oncogenic transformation over the past 100 years since the first published report of an oncogenic virus with particular attention to Env‐induced transformation. Copyright © 2008 John Wiley & Sons, Ltd.
Dose‐escalation designs in oncology: ADEPT and the CRM
Authors: Shu Jianfen , O'Quigley John
Published: August 2008

The ADEPT software package is not a statistical method in its own right as implied by Gerke and Siedentop (Statist. Med. 2008; DOI: 10.1002/sim.3037). ADEPT implements two‐parameter CRM models as described in O'Quigley et al. (Biometrics 1990; 46(1):33–48). All of the basic ideas (use of a two‐parameter logistic model, use of a two‐dimensional prior for the unknown slope and intercept parameters, sequential estimation and subsequent patient allocation based on minimization of some loss function, flexibility to use cohorts instead of one by one inclusion) are strictly identical. The only, and quite trivial, difference arises in the setting of the prior. O'Quigley et al. (Biometrics 1990; 46(1):33–48) used priors having an analytic expression whereas Whitehead and Brunier (Statist. Med. 1995; 14:33–48) use pseudo‐data to play the role of the prior. The question of interest is whether two‐parameter CRM works as well, or better, than the one‐parameter CRM recommended in O'Quigley et al. (Biometrics 1990; 46(1):33–48). Gerke and Siedentop argue that it does. The published literature suggests otherwise. The conclusions of Gerke and Siedentop stem from three highly particular, and somewhat contrived, situations. Unlike one‐parameter CRM (Biometrika 1996; 83:395–405; J. Statist. Plann. Inference 2006; 136:1765–1780; Biometrika 2005; 92:863–873), no statistical properties appear to have been studied for two‐parameter CRM. In particular, for two‐parameter CRM, the parameter estimates are inconsistent. This ought to be a source of major concern to those proposing its use. Worse still, for finite samples the behavior of estimates can be quite wild despite having incorporated the kind of dampening priors discussed by Gerke and Siedentop. An example in which we illustrate this behavior describes a single patient included at level 1 of 6 levels and experiencing a dose limiting toxicity. The subsequent recommendation is to experiment at level 6! Such problematic behavior is not common. Even so, we show that the allocation behavior of two‐parameter CRM is very much less stable than that of one‐parameter CRM. Copyright © 2008 John Wiley & Sons, Ltd.
Multiple imputation to correct for partial verification bias revisited
Authors: de Groot J. A. H. , Janssen K. J. M. , Zwinderman A. H. , Moons K. G. M. , Reitsma J. B.
Published: August 2008

Partial verification refers to the situation where a subset of patients is not verified by the reference (gold) standard and is excluded from the analysis. If partial verification is present, the observed (naive) measures of accuracy such as sensitivity and specificity are most likely to be biased. Recently, Harel and Zhou showed that partial verification can be considered as a missing data problem and that multiple imputation (MI) methods can be used to correct for this bias. They claim that even in simple situations where the verification is random within strata of the index test results, the so‐called Begg and Greenes (B&G) correction method underestimates sensitivity and overestimates specificity as compared with the MI method. However, we were able to demonstrate that the B&G method produces similar results as MI, and that the claimed difference has been caused by a computational error. Additional research is needed to better understand which correction methods should be preferred in more complex scenarios of missing reference test outcome in diagnostic research. Copyright © 2008 John Wiley & Sons, Ltd.
Carbon Nanotubes as Liquid Crystals
Authors: Zhang Shanju , Kumar Satish
Published: August 2008

Carbon nanotubes are the best of known materials with a combination of excellent mechanical, electronic, and thermal properties. To fully exploit individual nanotube properties for various applications, the grand challenge is to fabricate macroscopic ordered nanotube assemblies. Liquid‐crystalline behavior of the nanotubes provides a unique opportunity toward reaching this challenge. In this Review, the recent developments in this area are critically reviewed by discussing the strategies for fabricating liquid‐crystalline phases, addressing the solution properties of liquid‐crystalline suspensions, and exploiting the practical techniques of liquid‐crystal routes to prepare macroscopic nanotube fibers and films.

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Alkyl‐Functionalized Oxide‐Free Silicon Nanoparticles: Synthesis and Optical Properties
Authors: Rosso‐Vasic Milena , Spruijt Evan , van Lagen Barend , De Cola Luisa , Zuilhof Han
Published: August 2008

Highly monodisperse silicon nanoparticles (1.57 ± 0.21 nm) are synthesized with a covalently attached alkyl monolayer on a gram scale. Infrared spectroscopy shows that these silicon nanoparticles contain only a few oxygen atoms per nanoparticle. XPS spectra clearly show the presence of unoxidized Si and attached alkyl chains. Owing to the relatively efficient synthesis (yields ≈100‐fold higher than of those previously reported) the molar extinction coefficient ε can be measured: εmax = 1.7 × 10−4 M−1cm−1, only a factor of 4 lower than that of CdS and CdSe nanoparticles of that size. The quantum yield of emission ranges from 0.12 (C10H21‐capping) to 0.23 (C16H33‐capping). UV/Vis absorption and emission spectroscopy show clear vibrational progressions (974 ± 14 cm−1; up to five vibrational bands visible at room temperature), resembling bulk SiC phonons, which support the monodispersity observed by TEM. This was also confirmed by time‐resolved fluorescence anisotropy measurements, which display a strictly monoexponential decay that can only be indicative of monodisperse, ball‐shaped nanoparticles.