bluuebunny/crossref_metadata_2025 huggingface dataset:
Neural cell adhesion molecule stimulates survival of premyelinating oligodendrocytes via the fibroblast growth factor receptor
Authors: Palser Anne L. , Norman Adele L. , Saffell Jane L. , Reynolds Richard
Published: September 2009

Axonal signals are critical in promoting the survival and maturation of oligodendrocytes during myelination, with contact‐dependent signals thought to play a key role. However, the exact nature of these signals remains unclear. Neural cell adhesion molecule (NCAM) is expressed by both axons and oligodendrocytes and is ideally localized to transduce signals from the axon. This study sought to investigate the influence of NCAM on premyelinating oligodendrocytes in vitro. Both a soluble molecule comprising the extracellular domain of NCAM and a peptide derived from the fibroblast growth factor receptor (FGFR) binding motif within the first fibronectin domain stimulated a dose‐dependent increase in survival of premyelinating oligodendrocytes in vitro. The survival effect was blocked by a mitogen‐activated protein kinase (MAPK) inhibitor and an FGFR inhibitor, suggesting that activation of MAPK signalling pathways following interaction with the FGFR is involved in the survival effect of NCAM. Furthermore, NCAM presented in a cellular monolayer induced an increase in radial process outgrowth of oligodendrocyte progenitor cells. These data suggest that NCAM may play a role in axon–oligodendrocyte signalling during myelination, leading to an increase in oligodendrocyte survival and process outgrowth following axonal contact. © 2009 Wiley‐Liss, Inc.
Molecular structure, vibrational spectroscopic, first‐order hyperpolarizability and HOMO, LUMO studies of 3‐hydroxy‐2‐naphthoic acid hydrazide
Authors: Karpagam J. , Sundaraganesan N. , Sebastian S. , Manoharan S. , Kurt M.
Published: September 2009

The Fourier‐transform infrared spectrum of 3‐hydroxy‐2‐naphthoic acid hydrazide (3H2NAH) was recorded in the region 4000–400 cm−1. The Fourier‐transform Raman spectrum of 3H2NAH was also recorded in the region 3500–10 cm−1. Quantum chemical calculations of energies, geometrical structure and vibrational wavenumbers of 3H2NAH were carried out by density functional theory (DFT/B3LYP) method with 6‐31G(d,p) as basis set. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. The values of the electric dipole moment (µ) and the first‐order hyperpolarizability (β) of the investigated molecule were computed using ab initio quantum mechanical calculations. The UV spectrum was measured in ethanol solution. The calculation results also show that the 3H2NAH molecule might have microscopic nonlinear optical (NLO) behavior with non‐zero values. A detailed interpretation of the infrared and Raman spectra of 3H2NAH is also reported based on total energy distribution (TED). The calculated HOMO and LUMO energies shows that charge transfer occur within the molecule. The theoretical FT‐IR and FT‐Raman spectra for the title molecule have also been constructed. Copyright © 2009 John Wiley & Sons, Ltd.
Raman spectra of nitrogen‐containing organic compounds obtained using a portable instrument at −15 °C at 2860 m above sea level
Authors: Jehlička J. , Culka A.
Published: September 2009

Well‐resolved Raman spectra of samples of nitrogen‐containing compounds were detected using a portable Raman instrument (Ahura First Defender XL) outdoors at a low ambient temperature of −15 °C and at an altitude of 2860 m (Pitztall, Austria). The portable Raman spectrometer tested here is equipped with a 785‐nm diode laser and a fixed frontal probe. Solid form of formamide, urea, 3‐methylpyridine, aniline, indene, 1‐(2‐aminoethyl)piperazine, indoline and benzofuran were detected unambiguously under high‐mountain field conditions. The main Raman features (strong, medium and partially weak bands) were observed at the correct wavenumber positions (with a spectral resolution 7–10 cm−1) in the wavenumber range 200–1600 cm−1. The results obtained demonstrate the possibility of employing a miniaturised Raman spectrometer as a key instrument for investigating the presence of nitrogen‐containing organic compounds and biomolecules outdoors under low temperature conditions. Within the payload designed by European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) for future missions, focussing not only on Mars, Raman spectroscopy represents an important instrumentation for the detection of organic nitrogen‐containing compounds relevant to life detection on planetary surfaces or near sub‐surfaces. Copyright © 2009 John Wiley & Sons, Ltd.
Can Raman spectroscopy detect cumulenic structures of linear carbon chains?
Authors: Innocenti Francesco , Milani Alberto , Castiglioni Chiara
Published: September 2009

The molecular and vibrational structures of cumulenic carbon chains are investigated by density functional theory calculations and compared with that of hydrogen‐capped polyynes. The small value of bond length alternation (BLA) along the CC bonds sequence obtained by geometry optimization of uncapped Cn chains and vinyl‐capped carbon chains confirms their cumulenic structure. It is demonstrated that for finite length chains the structural parameters are determined by end effects as far as the Peierls distortion, expected for very long molecules, does not occur. The Raman spectra of such molecules are calculated to verify the possibility of identifying markers of cumulenic chains by means of vibrational spectroscopy. As expected, the longitudinal mode consisting of the BLA oscillation, which is responsible for the strongest Raman transition of polyynes, becomes very weak for cumulenes; this behaviour is rationalized in terms of local polarizability derivatives. However, other longitudinal modes can be observed in the Raman spectra of Cn chains. The wavenumber behaviour and the optical activity of these modes are interpreted on the basis of the phonon dispersion branch of an ideally infinite cumulenic polymer. Raman intensities computed for chains of different lengths allow to conclude that cumulenic molecules could be detected and identified by means of Raman spectroscopy. Copyright © 2009 John Wiley & Sons, Ltd.
Vibrational spectroscopy study of hydrothermally produced scorodite (FeAsO4·2H2O), ferric arsenate sub‐hydrate (FAsH; FeAsO4·0.75H2O) and basic ferric arsenate sulfate (BFAS; Fe[(AsO4)1−x(SO4)x(OH)x]·wH2O)
Authors: Gomez M. A. , Assaaoudi H. , Becze L. , Cutler J. N. , Demopoulos G. P.
Published: September 2009

Three crystalline ferric arsenate phases: (1) scorodite; FeAsO4·2H2O, (2) ferric arsenate sub‐hydrate (FAsH; FeAsO4·0.75H2O) and (3) basic ferric arsenate sulfate (BFAS; Fe[(AsO4)1−x(SO4)x(OH)x]·wH2O) synthesized by hydrothermal precipitation (175–225 °C) from Fe(III)‐AsO43−–SO42− solutions have been investigated via Raman and infrared spectroscopies. The spectroscopic nature of these high‐temperature Fe(III)‐ AsO43−–SO42− phases has not been extensively studied despite their importance to the hydrometallurgical industrial processing of precious metal (Au and Cu) arsenic sulfidic ores. It was found that scorodite, FAsH and BFAS all gave rise to very distinct arsenate, sulfate and hydroxyl vibrations. In scorodite and FAsH, the distribution of the internal arsenate modes was found to be distinct, with the factor effect being more predominant in the crystal system. For the crystallographically unknown BFAS phase, vibrational spectroscopy was used to monitor the arsenate ↔ sulfate solid solution behavior that occurs in this phase where the molecular symmetry of arsenate and sulfate in the crystal structure is reduced from an ideal Td to a distorted Td or C2/C2v symmetry. With the new collected vibrational data of the pure phases, the use of attenuated total reflectance infrared (ATR‐IR) spectroscopy was finally extended to investigate the nature of the arsenate in an industrial residue generated by pressure oxidation of a gold ore, where it was found that the arsenate was present in the form of BFAS. Copyright © 2009 John Wiley & Sons, Ltd.
Molecular imprinting of AMP by an ionic‐noncovalent dual approach
Authors: Breton Florent , Delépée Raphaël , Agrofoglio Luigi A.
Published: September 2009

In order to mimic recognition properties of adenylate kinase, molecularly imprinted polymers (MIPs) were prepared for adenosine 5′‐monophosphate (AMP), a substrate of the enzyme. Different functional monomers interacting with the phosphate moiety were tested, and the MIP giving the best specific binding of AMP was composed with one equivalent of 2‐(dimethylamino)ethyl methacrylate and ten equivalents of acrylamide compared to AMP. Packed into solid phase cartridge, this polymer showed similar characteristics than the enzyme, since it was specific for AMP toward other nucleotides.
Studies towards enantioselective surface imprinted polymers
Authors: Yilmaz Ecevit , Billing Johan , Boyd Brian , Möller Per , Rees Anthony
Published: September 2009

Molecularly imprinted polymers (MIPs) are tailor‐made materials that can specifically rebind desired target molecules. Usually, the template is in solution with monomers that form a specific polymeric cavity around the template. Here, a model system with an amino acid (Fmoc‐L‐Histidine) is presented. This new approach entails the imprinting of templates that are bound to support materials. It is shown that the new approach leads to materials that exhibit symmetric peak shapes for both enantiomers under isocratic conditions.
Selective sample pretreatment by molecularly imprinted polymer for the determination of LSD in biological fluids
Authors: Chapuis‐Hugon Florence , Cruz‐Vera Marta , Savane Ramatoulaye , Ali Wassim Hadj , Valcarcel Miguel , Deveaux Marc , Pichon Valerie
Published: September 2009

For the first time, a molecularly imprinted polymer (MIP) was synthesized by a noncovalent imprinting approach for the selective extraction of an illicit drug, LSD, from hair and urine samples. For the synthesis of MIP, an analog of LSD, was taken as a dummy template, methacrylic acid as a functional monomer, and ACN as a porogen solvent. The MIP was used for offline extraction before HPLC‐MS analysis. By studying the interactions taking place between the LSD and the MIP, a selective procedure was established in organic media and applied to hair samples. By this way, 0.1 ng/mg of LSD was successfully detected in hair with 82% of extraction recovery. A low retention was also obtained on the control polymer (only 9%). This procedure was then modified to obtain a selective extraction in aqueous media for the determination of LSD in urine samples. The comparison with a conventional C18 clearly demonstrated the selectivity brought by the MIP to the determination of LSD in urine. LSD was easily detected in urine at only 0.5 ng/mL with 83% of extraction recovery on the MIP and 11% on the NIP. An LOQ of 0.2 pg/mL was estimated in urine samples.
Cartilage myringoplasty
Authors: Klacansky Juraj
Published: September 2009

Myringoplasty is considered the simplest reconstructive procedure of the middle ear. There are many variations and types of myringoplasties. In the past, these variations were categorized according to the types of tissue and the way the tissue was fixated in the middle ear. Currently, the types of myringoplasties are differentiated only by the fixation of the transplant, because a majority of ear surgeons use only fascia, perichondrium, or cartilage. The percentage of successful healings after myringoplasties does not depend on the tissue used. More important is the condition of the middle ear at the time of the operation and the experience and skill of the surgeon. Regardless which type of tissue is used, 90% to 95% of good anatomical healing can be achieved. The author of this article performed more than 7,000 cartilage myringoplasties and presents his experience and alternatives of cartilage use in the eardrum reconstructions. He introduces three types of cartilage grafts: 1) island cartilage graft, 2) ring cartilage graft, and 3) double island cartilage graft. Laryngoscope, 2009
Strategies for Zonal Cartilage Repair using Hydrogels
Authors: Klein Travis J. , Rizzi Simone C. , Reichert Johannes C. , Georgi Nicole , Malda Jos , Schuurman Wouter , Crawford Ross W. , Hutmacher Dietmar W.
Published: September 2009

Articular cartilage is a highly hydrated tissue with depth‐dependent cellular and matrix properties that provide low‐friction load bearing in joints. However, the structure and function are frequently lost and there is insufficient repair response to regenerate high‐quality cartilage. Several hydrogel‐based tissue‐engineering strategies have recently been developed to form constructs with biomimetic zonal variations to improve cartilage repair. Modular hydrogel systems allow for systematic control over hydrogel properties, and advanced fabrication techniques allow for control over construct organization. These technologies have great potential to address many unanswered questions involved in prescribing zonal properties to tissue‐engineered constructs for cartilage repair.

magnified image
Cyclodextrin Complexation for Affinity‐Based Antibiotic Delivery
Authors: Thatiparti Thimma Reddy , von Recum Horst A.
Published: September 2009

Novel β‐cyclodextrin polymer (CD)‐based drug delivery hydrogels were prepared by varying type and concentration of crosslinkers and optimizing the gel synthesis conditions. For comparison, dextrose gels were prepared using the same crosslinkers. The optimized gels were characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), and X‐ray diffraction (XRD) as well as swelling and release studies. For drug release studies, the gels were loaded with three different model antibiotics varying in size and hydrophobicity: rifampin (RM), novobiocin (NB), and vancomycin (VM), using a common solvent method. The loading efficiency was calculated and release kinetics were determined in vitro. As expected for affinity‐based mechanisms, the release of drugs, from CD‐based gels, was slower than release from dextrose gels which indicated that the antibiotics all form inclusion complexes with CD. Release kinetics were also more linear in the observed time frame when using CD‐based hydrogels versus dextrose hydrogels. This modification in release depended on the affinity‐between CD and drug, such that larger drugs and more hydrophilic ones had their release profiles altered less than small hydrophobic ones. In conclusion, affinity‐based mechanisms can be used to load antibiotics and obtain longer, more linear release profiles than purely diffusion‐based mechanisms.

magnified image
Studies on corrosion inhibition of copper by alkanethiol SAMs prepared in aqueous micellar solution
Authors: Wang P. , Liang C. , Huang N.
Published: September 2009

The character of 1‐dodecanethiol (DT) self‐assembled monolayers (SAMs) formed on copper surface in aqueous micellar solution is investigated by means of contact angle measurement, electrochemical impedance spectroscopy (EIS), and polarization curves. The contact angle measurement shows that the SAMs formed in aqueous micellar solution are oriented and compact. According to the electrochemical measurements, it is found that both the concentration of DT and temperature can significantly affect the property of SAMs. The DT SAMs can prevent the corrosion of copper in chloride‐containing solution effectively because the inhibition efficiency can reach 99.59% at the DT concentration of 10−2 M. The adsorption of DT in aqueous micellar solution obeys to the Langmuir adsorption isotherm, and the value of the free energy of adsorption calculated indicates that the adsorption of DT molecule is a spontaneous process and a typical of chemical adsorption.
Micelle Behavior of Copolymers Composed of Linear and Hyperbranched Blocks in Aqueous Solution
Authors: Lim Su‐Hoon , Cha Eui‐Joon , Huh June , Ahn Cheol‐Hee
Published: September 2009

Multi‐arm poly(THF)‐b‐polyglycerol linear‐hyperbranched copolymers consisting of a linear hydrophobic poly(THF) block and a hyperbranched hydrophilic polyglycerol block were synthesized by ring opening polymerization of tetrahydrofuran with silver trifluoromethane sulfonate as a catalyst and the consecutive polymerization of glycidol. Initiators with different geometries that propagated into different numbers of arms (e.g., 1, 2 or 4) were used to investigate the dependence of the micelle properties of the copolymers on the number of arms. The critical micelle concentration (CMC) first decreased and then increased with increasing numbers of arms showing a minimum CMC at an arm number of 2. A minimum CMC was difficult to obtain using multi‐arm block copolymers composed of linear polymers with the small number of arms investigated in this study. DLS showed that the 4‐arm poly(THF)‐b‐polyglycerol copolymer had a micelle size of approximately 83 nm under aqueous conditions, and the micelle size of the copolymers with different numbers of arms was similar. Unimolecular micelles could eventually be obtained using this system by increasing the number of arms, they are considered an ideal drug delivery carrier due to the concentration‐independent stability in the blood stream.

magnified image
A Facile Route to Prepare Organic/Inorganic Hybrid Nanomaterials by ‘Click Chemistry’
Authors: Lu Xunyu , Sun Fu , Wang Jing , Zhong Jianfeng , Dong Qingzhi
Published: September 2009

An organosilane with an alkyne group at the non‐condensable end, [(2‐propynylcarbamate)propyl]triethoxysilane, has been synthesized. Condensation of this organosilane with tetraethoxysilane can be achieved by a co‐condensation strategy to produce silica nanoparticles with surface alkyne functionality. The size and uniformity of size distribution of the silica nanoparticles are influenced by varying the concentration of the added organosilane. The alkyne‐functionalized silica nanoparticles are coupled directly with azide‐modified polymers by ‘click chemistry’ to yield organic–inorganic hybrid nanomaterials.

magnified image
On Helmholtz decompositions and their generalizations—An overview
Authors: Sprössig W.
Published: September 2009

Helmholtz' theorem initiates a remarkable development in the theory of projection methods that are adapted to the numerical solution of equations in fluid dynamics and elasticity. There is a dense connection with Hodge‐de Rham decompositions of smooth 1‐forms. We give an overview of this type of decompositions and discuss their applications to vector, quaternionic and Clifford‐valued boundary value problems in the corresponding Hilbert–Sobolev spaces. Copyright © 2009 John Wiley & Sons, Ltd.
Work and energy equations and the principle of generalized effective stress for unsaturated soils
Authors: Zhao C. G. , Liu Y. , Gao F. P.
Published: September 2009

The effective stress principle has been efficiently applied to saturated soils in the soil mechanics and geotechnical engineering practice; however, its applicability to unsaturated soils is still under debate. The appropriate selection of stress state variables is essential for the construction of constitutive models for unsaturated soils. Owing to the complexity of unsaturated soils, it is difficult to determine the deformation and strength behaviors of unsaturated soils uniquely with the previous single‐effective‐stress variable theory and two‐effective‐stress‐variable theory in all the situations. In this paper, based on the porous media theory, the specific expression of work is proposed, and the effective stress of unsaturated soils conjugated with the displacement of the soil skeleton is further derived. In the derived work and energy balance equations, the energy dissipation in unsaturated soils is taken into account. According to the derived work and energy balance equations, all of the three generalized stresses and the conjugated strains have effects on the deformation of unsaturated soils. For considering these effects, a principle of generalized effective stress to describe the behaviors of unsaturated soils is proposed. The proposed principle of generalized effective stress may reduce to the previous effective stress theory of single‐stress variable or the two‐stress variables under certain conditions. This principle provides a helpful reference for the development of constitutive models for unsaturated soils. Copyright © 2009 John Wiley & Sons, Ltd.
Complex geometric models of diffusion and relaxation in healthy and damaged white matter
Authors: Landman Bennett A. , Farrell Jonathan A. D. , Smith Seth A. , Reich Daniel S. , Calabresi Peter A. , van Zijl Peter C. M.
Published: September 2009

Which aspects of tissue microstructure affect diffusion weighted MRI signals? Prior models, many of which use Monte‐Carlo simulations, have focused on relatively simple models of the cellular microenvironment and have not considered important anatomic details. With the advent of higher‐order analysis models for diffusion imaging, such as high angular resolution diffusion imaging (HARDI), more realistic models are necessary. This paper presents and evaluates the reproducibility of simulations of diffusion in complex geometries. Our framework is quantitative, does not require specialized hardware, is easily implemented with little programming experience, and is freely available as open‐source software. Models may include compartments with different diffusivities, permeabilities, and T2 time constants using both parametric (e.g. spheres and cylinders) and arbitrary (e.g. mesh‐based) geometries. Three‐dimensional diffusion displacement probability functions are mapped with high reproducibility, and thus can be readily used to assess reproducibility of diffusion‐derived contrasts. Copyright © 2009 John Wiley & Sons, Ltd.
The maleimide modified epoxy resins for the preparation of UV‐curable hybrid coatings
Authors: Altıntaş Zerrin , Karataş Sevim , Kayaman‐Apohan Nilhan , Güngör Atilla
Published: September 2009

In the present study, maleimide‐modified epoxide resin containing UV‐curable hybrid coating materials were prepared and coated on polycarbonate substrates in order to improve their surface properties. UV‐curable, bismaleimide‐modified aliphatic epoxy resin was prepared from N‐(p‐carboxyphenyl) maleimide (p‐CPMI) and cycloaliphatic epoxy (Cyracure‐6107) resin. The structure of the bismaleimide modified aliphatic epoxy resin was analyzed by FTIR and the characteristic absorption band for maleimide ring was clearly observed at 3100 cm−1. Silica sol was prepared from tetraethylorthosilicate (TEOS) and methacryloxy propyl trimethoxysilane (MAPTMS) by sol–gel method. The coating formulations with different compositions were prepared from UV‐curable bismaleimide‐based epoxy oligomer and sol–gel mixture. The molecular structure of the hybrid coating material was analyzed by 29Si‐CP/MAS NMR spectroscopy techniques. In the 29Si CP/MAS NMR spectrum of the hybrid coating, mainly two kinds of signals were observed at −68 and −110 ppm that correspond to T3 and Q4 peaks, respectively. This result shows that a fully condensed structure was obtained. The thermal and morphological properties of these coatings materials were investigated by using TGA and SEM techniques. Hardness and abrasion resistance properties of coating materials were examined and both were found to increase with sol–gel precursor content of the coating. The photopolymerization kinetics was investigated by using RT‐IR. 70% conversion was attained with the addition of 15 wt% of BMI resin into the acrylate‐based coating formulation. It was found that the UV‐curable organic–inorganic hybrid coatings improved the surface properties of polycarbonate. Copyright © 2009 John Wiley & Sons, Ltd.
Efficient polymers in conjunction with membranes to remove As(V) generated in situ by electrocatalytic oxidation
Authors: Rivas Bernabé L. , Aguirre María del Carmen , Pereira Eduardo , Bucher Christophe , Moutet Jean‐Claude , Aman Eric Saint , Royal Guy
Published: September 2009

Electrochemistry and ultrafiltration membrane methods (electro‐oxidation and liquid phase polymer based retention technique LPR, respectively) were coupled to remove As(III) inorganic species from aqueous solutions. Our main objective was to achieve an efficient extraction of arsenic species by associating a polymer‐assisted liquid phase retention procedure, based on the As(V) adsorption properties of cationic water‐soluble polymers, with the electrocatalytic oxidation process of As(III) into its more easily removable analog As(V). The exhaustive oxidation of As(III)–As(V) was readily performed in high yield at iridium oxide film modified carbon felt electrodes in the presence of different water‐soluble poly(quaternary ammonium) salts acting also as supporting electrolyte. The progress of the macro‐scale oxidation of As(III)–As(V) was followed using iridium oxide film modified glassy carbon electrodes. Finally, a study on arsenic retention by LPR‐technique performed on fully oxidized solutions of arsenic, showing that complete (100%) retention of the arsenic could be achieved using a 20:1 polyammonium:As(III) mole ratio. Copyright © 2009 John Wiley & Sons, Ltd.
Thermally conductive boron nitride/SEBS/EVA ternary composites: “Processing and characterization”
Authors: Kemaloglu Sebnem , Ozkoc Guralp , Aytac Ayse
Published: September 2009

The aim of this study is to investigate the effect of hexagonal boron nitride (BN) particle shape/size and loading level on the thermal, mechanical, electrical properties, and morphology of styrene‐ethylene‐butylene‐styrene terpolymer (SEBS)/poly(ethylene‐co‐vinyl acetate) (EVA) blends to be used as thermal interface materials (TIM). It is observed from the scanning electron microscopy (SEM) of BN powders that each type has a characteristic particle size distribution and particle shape. SEM analysis conducted on matrices (i.e. SEBS/EVA blends) does not indicate any sign of interfacial delamination or phase separation between components. The surface energy measurements and subsequent wettability coefficient calculations point out that the dispersion of BN in SEBS is thermodynamically more favorable than that of BN in EVA. In other words, SEBS tends to encapsulate BN particles in comparison to EVA. Thermal conductivity of composites increases with increasing filler loading level regardless of filler size and shape. It is found that the composites with smaller BN particles (i.e. high aspect ratio and plate‐like particles) shows higher thermal conductivity than that of the composites with larger particles at the same filler content. The tensile strength of the composites reduces with the incorporation of BN regardless of BN content and matrix composition. The increasing content of BN in the matrix gradually improves the moduli of the composites. The hardness of composites enhances with BN loading level and SEBS/EVA ratio regardless of filler type. The increasing amount of EVA in the composites results in a decrease in dielectric constant of neat matrices and composites. POLYM. COMPOS., 31:1398–1408, 2010. © 2009 Society of Plastics Engineers
Substituent effects on conformational preference in α‐substituted α‐fluorophenylacetic acid methyl ester model systems for chiral derivatizing agents
Authors: Sahnoun Riadh , Fujimura Yuichi , Kabuto Kuninobu , Takeuchi Yoshio , Noyori Ryoji
Published: September 2009

In connection with study of chiral derivatizing agents (CDAs) for NMR determination of absolute configuration of organic compounds, factors controlling the conformational preference between syn‐ and anti‐forms in α‐substituted α‐fluorophenylacetic acid methyl ester (FC(X)(Ph)COOMe) model systems were theoretically investigated. Substituents X at the stereogenic carbon atom were X = H, CCH and CH3, the electronic and steric properties of which were significantly different from each other. The model system with X = CCH and that with X = CH3 were found to be possible candidates for fluorine‐containing CDAs. The syn conformation is stable compared with the anti one by 0.7 kcal mol−1 for the ester with X = CCH. On the other hand, the anti conformation is stable compared with the syn one by 0.5 kcal mol−1 for the ester with X = CH3. Both natural bond orbital (NBO) analysis and deletion of selected orbitals based on the donor–acceptor NBO scheme were adopted for semi‐quantitative estimation of factors responsible for the conformational preference as well as a qualitative inspection of occupied canonical molecular orbitals (MOs). It was shown that [σ–(σ* + π*)(CO)] and [σ–σ*(Ph) and π(Ph)–σ*] hyperconjugations are the main factors controlling the conformational preferences between the syn and anti conformations. Other types of effects such as electrostatic effects were also investigated. The role of the fluorine atom was also clarified. Copyright © 2009 John Wiley & Sons, Ltd.
Naphthalene‐based poly(arylene ether ketone) copolymers containing sulfobutyl pendant groups for proton exchange membranes
Authors: Shao Ke , Zhu Jing , Zhao Chengji , Li Xianfeng , Cui Zhiming , Zhang Yang , Li Hongtao , Xu Dan , Zhang Gang , Fu Tiezhu , Wu Jing , Na Hui , Xing Wei
Published: September 2009

A new monomer 1,5‐bis(4‐fluorobenzoyl)‐2,6‐dimethoxynaphthalene (DMNF) was prepared and further polymerized to form naphthalene‐based poly(arylene ether ketone) copolymers containing methoxy groups (MNPAEKs). The side‐chain‐type sulfonated naphthalene‐based poly(arylene ether ketone) copolymers (SNPAEKs) were obtained by demethylation and sulfobutylation. Flexible and tough membranes with reasonably high mechanical strength were prepared. The SNPAEKs membrane showed anisotropic membrane swelling with larger swelling in thickness than in plane. Transmission electron microscopy (TEM) analysis revealed clear nanophase separated structure of SNPAEKs membranes, which composed of hydrophilic side chain and hydrophobic main‐chain domains. Proton conductivities of copolymers increased gradually with increase in temperature. The highest conductivity of 0.179 S/cm was obtained for SNPAEK‐80 (IEC = 1.82 mequiv/g) at 80 °C, which is higher than that of Nafion117 (0.146 S/cm). The SNPAEKs membranes exhibit the methanol permeability in the range of 3.42 × 10−8−4.49 × 10−7 cm2/s, which are much lower than that of Nafion117. They could be the promising materials as alternative to Nafion membrane for direct methanol fuel cells applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47:5772–5783, 2009
The Influence of Surface Treatment on Photocatalytic Activity of PE CVD TiO2 Thin Films
Authors: Hajkova Pavlina , Spatenka Petr , Krumeich Joerg , Exnar Petr , Kolouch Ales , Matousek Jindrich
Published: September 2009

The aim of this paper is investigation of the photocatalytic properties of TiO2 thin films prepared by PECVD with metal nanoparticles built‐up on the film surface. The deposition of TiO2 films was carried out in the radio frequency (RF) low‐pressure PECVD reactor. Layers were deposited at two different substrate temperatures (40 and 300 °C). The surface of TiO2 films was subsequently covered by noble metal nanoparticles—silver, platinum, and gold, deposited by different methods. For determination of the photocatalytic decomposition the Acid orange 7 (AO7) C16H11N2NaO4S organic dye was used. Selected samples were used for antibacterial tests (Gram‐negative bacteria Escherichia coli). The results clearly proved that presence of metal clusters resulted in enhancement of the photocatalytic and antibacterial activity.
Thin Protective Aluminum Layer on Mg‐Li Alloy by Plasma Spraying and Cold Rolling
Authors: Oki Sachio , Tsujikawa Masato , Morishige Taiki , Kamita Masaichiro
Published: September 2009

Formation of a protective thin surface of pure aluminum on Mg‐14mass%Li alloy by plasma thermal spraying and the cold rolling was investigated. An Mg‐14mass%Li‐1mass%Al alloy ingot was melted and cast in a pressurized argon atmosphere. After homogeneous heat treatment, the ingot was rolled to 3 mm‐thick plate with a reduction ratio of 98%. The plate specimens were annealed again. Plasma sprayings of pure aluminum were carried out with various conditions after grit blasting. The coated layer thickness was about 100 µm. There was slight increase in temperature during spraying on substrates. The first pass of rolling was carried out at 250 °C; then several cold rolling passes were processed to reduce the entire thickness up to 90% in reduction ratio of the sprayed specimens' thickness. It was found that the determining factor for sound rolled sheet without separation of aluminum coating was the maximum temperature of the substrate at plasma processing. There were no separation, for specimen heated in the temperature range between 300 and 400 °C during thermal spraying, at rolling up to 90% in total reduction ratio. Sectional observation revealed a continuous thin aluminum layer adhered on the Mg‐14mass%Li alloy.
Changes in the urinary proteome post‐operatively in renal cancer patients – a reflection of tumour or kidney removal?
Authors: Sim Sheryl H. , Cairns David A. , Perkins David N. , Peng Jianhe , Stanley Anthea J. , Thompson Douglas , Lewington Andrew , Selby Peter J. , Banks Rosamonde E.
Published: September 2009

During the initial phases of a study focussed on discovering new urinary biomarkers for renal cell carcinoma, a number of challenges and limitations were identified, which we subsequently investigated. The purpose of this report is to provide insight into experimental design for such investigations and potential confounding factors that can impact on such studies. Sixty urine samples from 20 patients with clear cell renal cell carcinoma and ten live renal transplant donor patients, pre‐ and post‐nephrectomy, were profiled using SELDI‐TOF‐MS incorporating stringent quality control and in‐house data processing/analysis. There were 65 significantly differentially expressed peaks (five solitary peaks and four peak clusters that increased post nephrectomy and four peak clusters that decreased). Peak 3934 Da m/z and peaks within 11731–11961 Da m/z, which increased post nephrectomy were identified as the 36 amino acid isoform of β‐defensin‐1 and β2‐microglobulin, respectively. However, changes in these two protein forms were also seen in healthy donors following nephrectomy implying a relationship with kidney removal per se rather than tumour removal. This study indicates the difficulties in identifying SELDI peaks for subsequent validation and illustrates the need for appropriate controls in biomarker studies to determine whether changes are indirect consequences of treatment.
Characterization of a novel novobiocin analogue as a putative C‐terminal inhibitor of heat shock protein 90 in prostate cancer cells
Authors: Matthews Shawna B. , Vielhauer George A. , Manthe Craig A. , Chaguturu Vamsee K. , Szabla Kristen , Matts Robert L. , Donnelly Alison C. , Blagg Brian S. J. , Holzbeierlein Jeffrey M.
Published: September 2009

PURPOSE

Hsp90 is important in the folding, maturation and stabilization of pro‐tumorigenic client proteins and represents a viable drug target for the design of chemotherapies. Previously, we reported the development of novobiocin analogues designed to inhibit the C‐terminal portion of Hsp90, which demonstrated the ability to decrease client protein expression. We now report the characterization of the novel novobiocin analogue, F‐4, which demonstrates improved cytotoxicity in prostate cancer cell lines compared to the N‐terminal inhibitor, 17‐AAG.

MATERIALS AND METHODS

LNCaP and PC‐3 cells were treated with 17‐AAG or F‐4 in anti‐proliferative, apoptosis, cell cycle and cytotoxicity assays. Western blot and prostate specific antigen (PSA) ELISAs were used to determine client protein degradation, induction of Hsp90 and to assess the functional status of the androgen receptor (AR) in response to F‐4 treatment. Surface plasmon resonance (SPR) was also used to determine the binding properties of F‐4 to Hsp90.

RESULTS

F‐4 demonstrated improved potency and efficacy compared to novobiocin in anti‐proliferative assays and decreased expression of client proteins. PSA secretion was inhibited in a dose‐dependent manner that paralleled a decrease in AR expression. The binding of F‐4 to Hsp90 was determined to be saturable with a binding affinity (Kd) of 100 µM. In addition, superior efficacy was demonstrated by F‐4 compared to 17‐AAG in experiments measuring cytotoxicity and apoptosis.

CONCLUSIONS

These data reveal distinct modes of action for N‐terminal and C‐terminal Hsp90 inhibitors, which may offer unique therapeutic benefits for the treatment of prostate cancer. Prostate 70: 27–36, 2010. © 2009 Wiley‐Liss, Inc.
Long term increased expression of the short form 1b prolactin receptor in PC‐3 human prostate cancer cells decreases cell growth and migration, and causes multiple changes in gene expression consistent with reduced invasive capacity
Authors: Huang Kuang‐tzu , Walker Ameae M.
Published: September 2009

BACKGROUND

We have shown that treatment of human prostate cancer cells with the selective prolactin (PRL) receptor modulator, S179D PRL, inhibits growth in vitro, and the initiation and growth of xenografts in vivo. S179D PRL treatment also upregulates expression of the short form 1b (SF1b) PRL receptor, activation of which upregulates expression of the cell cycle‐regulating protein, p21.

METHODS

We examined the consequences of long term increased expression and activation of SF1b, at levels comparable to those resulting from treatment with S179D PRL, by creating PC‐3‐derived stable cell lines expressing a constitutively active form of SF1b, ΔS2 SF1b.

RESULTS

Increased expression of ΔS2 SF1b decreased growth and migration of the cells. This was accompanied by an increase in cell‐matrix interactions, and cell–cell aggregation when cells were plated on basement membrane components. Real‐time PCR evaluated the expression of genes related to invasive capacity. Of particular interest was decreased expression of the protease, urokinase‐type plaminogen activator, and its receptor, uPAR, and increased expression of its inhibitors, PAI‐1 and 2. Also decreased in cells with increased expression of ΔS2 SF1b was expression of basic fibroblast growth factor and vascular endothelial growth factor.

CONCLUSION

We conclude that at least part of the beneficial effects of S179D PRL is the result of increased expression of SF1b, and that the effects of increased expression and activation of SF1b continue to be of potential benefit in the long term. Prostate 70: 37–47, 2010. © 2009 Wiley‐Liss, Inc.
Global levels of histone modifications predict prostate cancer recurrence
Authors: Ellinger Jörg , Kahl Philip , von der Gathen Johannes , Rogenhofer Sebastian , Heukamp Lukas C. , Gütgemann Ines , Walter Bernhard , Hofstädter Ferdinand , Büttner Reinhard , Müller Stefan C. , Bastian Patrick J. , von Ruecker Alexander
Published: September 2009

PURPOSE

Epigenetic alterations such as DNA methylation and histone modifications play important roles in carcinogenesis. It was reported that global histone modification patterns are predictors of cancer recurrence in various tumor entities. Our study was performed to evaluate histone lysine (HxKy) and histone acetyl (HxAc) modifications in prostate tissue.

MATERIALS AND METHODS

A tissue microarray with 113 prostate cancer (PCA), 23 non‐malignant prostate tissues was stained with antibodies against H3K4 mono‐(H3K4me1), di‐(H3K4me2), tri‐(H3K4me3) methylation, H3K9me1, H3K9me2, H3K9me3, H3 and H4 pan‐acetylation (H3Ac, H4Ac). We also analyzed H3K4 methylation in patients with advanced PCA (hormone‐refractory PCA—HRPC, n = 34; hormone‐dependent PCA, n = 30). Sections were scored according the staining intensity and the proportion of epithelial cells showing nuclear staining.

RESULTS

H3K4me1, H3K9me2, H3K9me3, H3Ac, and H4Ac were significantly reduced in PCA compared to non‐malignant prostate tissue. H3Ac and H3K9me2 levels allowed discrimination of PCA and non‐malignant prostate tissue highly specifically (>91%) and sensitively (>78%) as determined via ROC analyses (AUC >0.91). Histone lysine methylation and histone acetylation marks were correlated with clinical–pathological parameters (i.e., digital rectal examination, preoperative PSA, pT‐stage, lymph node metastasis, Gleason score). In addition, H3K4me1 was a significant predictor of PSA recurrence following radical prostatectomy. H3K4me1, H3K4me2, and H3K4me3 levels were significantly increased in HRPC.

CONCLUSIONS

Global histone modification levels may help to identify patients with adverse prognosis, and represent a target for the future therapy of PCA. Prostate 70: 61–69, 2010. © 2009 Wiley‐Liss, Inc.
PSA and body composition by dual X‐Ray absorptiometry (DXA) in NHANES
Authors: Fowke Jay H. , Matthews Charles E.
Published: September 2009

BACKGROUND

Obese men are at higher risk for advanced prostate cancer and have a poorer prognosis following treatment. Several studies also report that obese men have lower blood PSA levels, suggesting that obesity may be interfering with the ability to detect early‐stage prostate cancer.

METHODS

Dual X‐ray absorptiometry (DXA) is considered a gold‐standard measurement of body composition. We investigated the association between PSA levels and body composition measured by DXA among 1,360 men participating in NHANES (2001–2004), a representative sample of the U.S. male population.

RESULTS

After controlling for age, race, and other factors, PSA concentration was ∼15% lower for men with the highest level of total mass, lean mass, fat mass, trunk lean mass, and trunk fat mass (all P for trend <0.05). We then multiplied PSA concentration by estimated plasma volume to calculate the amount of PSA in circulation (i.e., PSA mass). Total body fat mass and fat mass located in the body trunk were not significantly associated with PSA mass, however, PSA mass was ∼10–15% higher across low versus high categories of total body lean mass and bone mineral content (all P‐trend <0.05).

CONCLUSION

Our results using DXA to measure body composition confirm that a greater body mass, not just fat mass, is associated with a lower PSA concentration. This is consistent with PSA hemodilution within men with a higher body mass index. The separate associations between measured lean and fat mass on calculated PSA mass require further investigation. Prostate 70: 120–125, 2010. ©2009 Wiley‐Liss, Inc.
Modifying the conserved C‐terminal tyrosine of the peptide hormone PYY3‐36 to improve Y2 receptor selectivity
Authors: Pedersen Søren L. , Holst Birgitte , Vrang Niels , Jensen Knud J.
Published: September 2009

The Y2 selective PYY derived peptide PYY3‐36 was recently shown to play a role in appetite regulation. Novel PYY3‐36 analogs with high selectivity for the Y2 receptor could be potential drug candidates for the treatment of obesity. The C‐terminal pentapeptide segment of PYY3‐36 is believed to bind to the Y receptors. Tyr‐36 is highly conserved across species and only few successful modifications of Tyr‐36 have been documented. PYY3‐36 analogs were prepared using solid‐phase peptide chemistry and tested for binding to the Y1, Y2 and Y4 receptor subtypes by radioligand displacement assay. The Y2 receptor agonists with the best affinity and selectivity were further investigated for activity towards the Y1 and Y2 receptor subtypes. Unexpectedly, modifications of Tyr‐36 were well‐tolerated, and the analogs of PYY3‐36 in which the Tyr‐36 hydroxyl group was substituted with a halogen or an amino group were particularly well tolerated and yielded an improved selectivity and approximately equipotent affinity to the Y2 receptor. These modifications could be used to design new potential drug candidates for the treatment of obesity. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Incorporation of N‐amidino‐pyroglutamic acid into peptides using intramolecular cyclization of α‐guanidinoglutaric acid
Authors: Burov Sergey , Moskalenko Yulia , Dorosh Marina , Shkarubskaya Zoya , Panarin Evgeny
Published: September 2009

N‐terminal modification of peptides by unnatural amino acids significantly affects their enzymatic stability, conformational properties and biological activity. Application of N‐amidino‐amino acids, positively charged under physiological conditions, can change peptide conformation and its affinity to the corresponding receptor. In this article, we describe synthesis of short peptides, containing a new building block—N‐amidino‐pyroglutamic acid. Although direct guanidinylation of pyroglutamic acid and oxidation of N‐amidino‐proline using RuO4 did not produce positive results, N‐amidino‐Glp‐Phe‐OH was synthesized on Wang polymer by cyclization of α‐guanidinoglutaric acid residue. In the course of synthesis, it was found that literature procedure of selective Boc deprotection using TMSOTf/TEA reagent is accompanied by concomitant side reaction of triethylamine alkylation by polymer linker fragment. It should be mentioned that independently from cyclization time and coupling agent (DIC or HCTU), the lactam formation was incomplete. Separation of the cyclic product from the linear precursor was achieved by HPLC in ammonium formate buffer at pH 6. HPLC analysis showed N‐amidino‐Glp‐Phe‐OH stability at acidic and physiological pH and fast ring opening in water solution at pH 9. The suggested method of N‐amidino‐Glp residue formation can be applied in the case of short peptide chains, whereas synthesis of longer ones will require fragment condensation approach. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Modeling the effects of molecule distortion on the Kondo resonance in the conductance of CoPc/Au(111) and TBrPP‐Co/Cu(111)
Authors: Aguiar‐Hualde J. M. , Chiappe G. , Louis E. , Anda E. V. , Simonin J.
Published: September 2009

Recent scanning tunneling microscope (STM) experimental studies on transport through CoPc and TBrPP‐Co molecules adsorbed on metallic surfaces have reported several interesting results: (i) a high Kondo temperature as compared to those of adsorbed undressed magnetic atoms, (ii) the Kondo resonance shows up either as a Kondo peak (CoPc) or as a Fano dip (TBrPP‐Co), (iii) the Kondo temperature depends strongly on the molecule conformation and can be manipulated experimentally. Aiming to propose a theoretical framework that may serve to analyze these observations, we first discuss the case of an isolated magnetic atom adsorbed on a metallic surface. Much of the work on this simple case turns out to be of great help in the analysis of the more complex systems. Then, a simple model is proposed that, capturing the main features of the inner structure of the molecule (four lobe orbitals plus a strongly correlated orbital), offers a physical interpretation for most of the observations on those two moecules. In addition, it allows predicting the behavior of the system upon other symmetry or conformational changes, or when the STM tip is moved away from the Co atom.
Field quenching in photoconductive CdS as possible reason to enhance Voc and FF in thin‐film solar cells
Authors: Böer Karl W.
Published: September 2009

Field‐quenching via Frenkel–Poole excitation of Coulomb attractive hole traps limits the field in the CdS part of the junctions to 50 kV/cm. This is far below the field in typical other pn‐junctions of thin‐film semiconductors, which exceeds 100 kV/cm and approaches tunneling fields that make junctions leaky, hence reduces both Voc and FF. Field‐quenched CdS may become electronically inverted, thereby providing a possibility that the junction of the CdS/CdTe cell may extend into the CdS, with the cell becoming a hetero structure. With field quenching a region of negative differential conductivity is created causing a high‐field domain that prevents the maximum electric field in the junction to exceed 50 kV/cm, avoiding tunneling, hence electron leakage through it. A preliminary band model of this cell is proposed.