bluuebunny/crossref_metadata_2025 huggingface dataset:
The synthesis of 9–10 Dibromo stearic acid glycidyl methacrylate and its use in vinyl ester resins
Authors: Can E. , La Scala J. J. , Sands J. M. , Palmese G. R.
Published: September 2007

In this study, 9–10 dibromo stearic acid glycidyl methacrylate (Di‐BrSAGMA) was synthesized from oleic acid and used as a replacement for styrene in vinyl ester (bisphenol A type VE (VE 828) and Novalac type VE (VE160)) to introduce fire retardance to these systems and to decrease the volatile organic compound (VOC) emissions caused by styrene. When the Di‐BrSAGMA was used as the comonomer, these resins exhibited too high viscosities, reduced modulus and glass transition temperature (Tg) values compared to those of the styrene based systems. Thus, the Di‐BrSAGMA was used in the presence of styrene in these resins. The viscosities of the resins with various Di‐BrSAGMA contents were determined and the modulus and the Tg values of the resulting polymers were measured via dynamic mechanical analysis (DMA) to determine the ideal formulations for each resin system. Similar analysis was performed, with similar oleic acid glycidyl methacrylate (OAGMA) contents, to determine the effect of the introduction of the bromine groups onto the network. Reactive diluent blends of the fatty acid based monomers with styrene, at styrene contents as low as 15–20 wt % at 35–45 wt % total comonomer content, in VE formulations were shown to have processable viscosities for liquid molding processes, and modulus and Tg values that are comparable to those of the commercial VE‐styrene systems. The effect of the replacement of styrene by the Di‐BrSAGMA monomer on the thermal degradation behavior of the VE 828 and VE 160 networks was also explored by thermal gravimetric analysis (TGA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Electrospun three‐dimensional silk fibroin nanofibrous scaffold
Authors: Ki Chang Seok , Kim Jong Wook , Hyun Jin Ho , Lee Ki Hoon , Hattori Masahiro , Rah Dong Kyun , Park Young Hwan
Published: September 2007

Practical application to three‐dimensional (3‐D) tissue culture has been limited by the structural restriction of two‐dimensional (2‐D) nature of electrospun nanofiber mat. In this study, for constructing 3‐D nanofibrous structure as real 3‐D tissue engineering scaffold, we developed new fabrication process with silk fibroin (SF) by electrospinning and evaluated the features of this SF nanofiber scaffold (SFNS) through morphological and cell‐culture analyses. Foam type of the SFNS exhibited high porosity as well as large pores and its cell proliferation well occurred inside (inner spaces of pores), which makes this suitable for 3‐D cell‐culture scaffold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Novel Ni/polypyrrole and Cu/polypyrrole composites prepared in the presence of different acids: Synthesis and investigation of thermal stability
Authors: Şen Songül , Gök Ayşegül , Gülce Handan
Published: September 2007

We report the synthesis and characterization of new organic/inorganic hybrid materials constituted of Ni(0) and Cu(0) nanoparticles and polypyrrole (PPy). Copper and nickel nanoclusters were synthesized by a chemical reduction of aqueous metal salt solutions by sodium borohydride. PPy/Ni(0) and PPy/Cu(0) composites were obtained in the presence of two different acids (H3BO3, CH3COOH), by polymerizing pyrrole‐Ni and pyrrole‐Cu particles by using iron (III) chloride. The composites have been characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and magnetic susceptibility techniques. Conductivity measurements of samples were taken using four‐probe devices. The PPy/Ni(0) and PPy/Cu(0) nanocomposites doped with different acids exhibited higher conductivity values than those of homopolymers. Among all samples, Ni/PPy‐H3BO3 has the highest conductivity (1.42 S cm−1). Homopolymers and composites showed a stable and increasing conductivity with increasing temperature, except Ni(0). We observed that from TGA analysis of polymers, metal composites of PPy synthesized in two different media are more stable than those of PPy‐CH3COOH and PPy‐H3BO3. The magnetic susceptibility values of homopolymers and Cu are negative, whereas the other samples are positive. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Design of a drug delivery system based on poly(acrylamide‐co‐acrylic acid)/chitosan nanostructured hydrogels
Authors: Becerra‐Bracamontes Fausto , Sánchez‐Díaz Juan C. , González‐Álvarez Alejandro , Ortega‐Gudiño Pedro , Michel‐Valdivia Enrique , Martínez‐Ruvalcaba Agustín
Published: September 2007

To obtain biodegradable materials for biomedical applications, new biopolymeric hydrogels based on blends of polyacrylamide nanoparticles and chitosan have been prepared. In this work, we have studied the behavior of the diffusion of ascorbic acid (V‐C) from poly(acrylamide‐co‐acrylic acid)/chitosan nanostructured hydrogels. The process involves the synthesis of nanoparticles of polyacrylamide by inverse microemulsion polymerization and their complexation with chitosan dissolved in an acrylic acid aqueous solution. We have studied the effect of the concentration of the polyacrylamide nanoparticles, which are crosslinked with N,N′‐methylenebisacrylamide, in the delivery of V‐C. The results indicate that the drug delivery operates by a non‐Fickian mechanism. Also, we have obtained the diffusion coefficient for V‐C in gels for different nanoparticle concentrations, using a modified form of Fick's second law that takes into account dimensional changes in the hydrogels during drug release. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and characterization of polycyanurate networks modified by oligo(ϵ‐caprolactone) as precursors of porous thermosets
Authors: Fainleib A. , Grigoryeva O. , Garda M. R. , Saiter J. M. , Lauprêtre F. , Lorthioir C. , Grande D.
Published: September 2007

Oligo(ϵ‐caprolactone)‐modified polycyanurate networks were synthesized by thermal polycyclotrimerization of dicyanate ester of bisphenol E in the presence of a dihydroxy‐telechelic poly(ϵ‐caprolactone) (PCL) oligomer with varying compositions. Using FTIR, gel fraction content and density measurements, it has been proved that the main part of the reactive modifier was chemically incorporated into the PCN network structure. According to the thermal behavior of the polymer networks as investigated by TGA, they can be divided into two groups. The first group of systems with low modifier content (i.e., up to 20 wt %) is characterized by one stage of decomposition under nitrogen, and two stages under oxygen. A second group of systems with higher modifier content is generally characterized by two stages of decomposition in nitrogen and three stages in oxygen. DSC and DMTA investigations have shown the occurrence of at least a two‐phase structure in all the samples. The PCN/PCL‐based hybrid networks can be effectively used as precursors for the generation of porous PCN thermosets, as evidenced by FTIR and SEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Influence of H+ and Cl− ions on inhibitive performance of poly(aniline) for iron corrosion in acid
Authors: Manivel P. , Sathiyanarayanan S. , Venkatachari G.
Published: September 2007

The inhibition effect of poly(aniline) on pure iron corrosion in 1M HCl and with various H+ ions and Cl− ions concentrations was investigated by the polarization and electrochemical impedance spectroscopy methods. The results showed that poly(aniline) suppressed both cathodic and anodic processes of iron dissolution in 1M HCl by its adsorption on the iron surface according to Langmuir's adsorption isotherm. The inhibition efficiency of poly(aniline) was found to increase with the inhibitor concentrations. Further, it was observed that, there was no significant variation in corrosion potential (Ecorr) values in the presence of inhibitors suggesting that, this polymer behaved as mixed type inhibitor. Similar studies for the inhibitor at 500 ppm in various concentrations of H+ and Cl− ions, have shown that the inhibition efficiency decreases with decrease in concentrations of H+ ions and Cl− ions in aqueous solution. It reveals that, the adsorption of inhibitor on iron surface is by more cationic form of inhibitor and higher efficiency at higher H+ and Cl− ions is due to enhanced adsorption of cat ionic form of inhibitor molecules. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Additives effects on the shrinkage behavior of PVC sheets
Authors: Hadi P. , Babaluo A. A.
Published: September 2007

Despite the unique applications of heat shrinkable PVC sheets in food packaging industry, a few works have been carried out on the shrinkage behavior of this kind of sheets. So, in our work, investigation of the shrinkability of PVC sheets and influence of different parameters on the above‐mentioned property has been focused, intensively. This paper presents the results of research aimed at characterizing the shrinkage behavior of PVC sheets, accompanied by the effect of different additives and their weight fractions on the shrinkability of the prepared sheets using experimental design Taguchi method. Also, shrinkage behavior of PVC sheets at optimum conditions has been studied and the stretching and shrinking temperature effects have been investigated. It was found that, among seven investigated variables, plasticizer has the most significant effect on the shrinkability of PVC sheets. Also, at optimum conditions, an increase in the stretching temperature can extensively influence the crystalline structure of the polymer and subsequently, shrinking temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Preparation and properties of dough‐modeling compound/fly ash/reclaim powder composites
Authors: Wu Weili
Published: September 2007

A novel composite was prepared with reclaim powder (RP) matrix, dough‐modeling compound (DMC) reinforcement and fly ash (FA) filler in this article. The compatibility and crosslinking construction of the FA/RP composites were respectively, studied by the polarizing microscope and IR, the optimal formulation and experimental process were determined by measuring the mechanical properties such as shore A hardness, tensile strength, elongation at break, wear resistance and the thermal stability. The results showed that DMC/FA/RP composites exhibited extremely high mechanical and thermal properties when the mass ratio of the DMC/FA/RP composites was 45/25/100, and the cure condition is at 145°C for 30 min under 9 MPa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Germanates of 1D Chains, 2D Layers, and 3D Frameworks Built from Ge–O Clusters by Using Metal‐Complex Templates: Host–Guest Symmetry and Chirality Transfer
Authors: Liu Guang‐Zhen , Zhang Hong‐Xia , Lin Zhi‐En , Zheng Shou‐Tian , Zhang Jie , Zhao Jing‐Tai , Wang Guo‐Ming , Yang Guo‐Yu
Published: September 2007

The self‐assembly of Ge–O polyhedra by metal‐complex templates leads to initial examples of open germanate structures under mild solvothermal conditions. These materials are constructed from Ge–O cluster building bocks (Ge7X19 (X=O, OH, or F) or Ni@Ge14O24(OH)3) and span the full range of dimensionalities from 1D chains of Ge7O13(OH)2F3⋅Cl⋅2[Ni(dien)2] (FJ‐6) to 2D layers of Ge7O14F3⋅0.5[In(dien)2]⋅0.5H3dien⋅ 2H2O (1) and 3D frameworks of Ni@ Ge14O24(OH)3⋅2[Ni(L)3] (FJ‐1 a/FJ‐1 b) (dien=diethylenetriamine, L=ethylenediamine (en) or 1,2‐diaminopropane (enMe)). The Ge7X19 cluster in FJ‐6 and 1 is formed by condensation of four GeX4 tetrahedra, two GeX5 trigonal bipyramids, and one GeX6 octahedron with a μ3‐O atom at the center of the cluster, whereas the Ni@ Ge14O24(OH)3 cluster in FJ‐1 a/FJ‐1 b is formed by condensation of nine peripheral GeO4 tetrahedra and five interior GeO3Ni units with one μ5‐Ni atom at the center of the cluster. FJ‐6 is characterized by a pair of racemic Ge7O14(OH)2F3 cluster chains and represents only one example of 1D germanates; 1 exhibits unique germanate layers with uniform 10‐membered‐ring apertures encapsulating an unknown indium complex, and the framework structure of FJ‐1 a/FJ‐1 b with large 24‐membered‐ring channels is the first example of porous materials that contain metal–metal bonds (Ge2+Ni+). These initial examples of germanates from metal‐complex templates provide a useful model system for understanding the mechanisms of host–guest interactions, which may further facilitate the design and development of new porous materials “on demand”. It is shown that the symmetry and configuration of the guest metal complex can be imprinted onto the host inorganic framework through hydrogen bonding between host and guest.
Finite‐Elemente‐Methode für geotechnische Nachweise nach neuer Normung?
Authors: Heibaum Michael , Herten Markus
Published: September 2007

Für geotechnische Berechnungen nimmt der Einsatz der Finite‐Elemente‐Methode (FEM) dank immer leistungsfähigerer Rechner zu, weshalb untersucht werden muss, inwieweit dieses Berechnungsverfahren für geotechnische Nachweise entsprechend den europäischen und deutschen Normen geeignet ist. Die nach Norm geforderten Sicherheiten basieren auf bestimmten Modellen und den damit vorliegenden Erfahrungen, die nicht ungeprüft auf andere Ansätze übertragen werden können. Für die Nachweise gemäß DIN 1054 bzw. dem Verfahren 2* nach EN 1997‐1 wird unter Verwendung von Berechnungsbeispielen gezeigt, dass Einwirkungen und Beanspruchungen gut mit der FEM ermittelt werden können. Auch Widerstände können durchaus berechnet werden. Die Erfahrungsgrundlage zur Beurteilung ihrer Verlässlichkeit ist jedoch zu gering, so dass zum gegenwärtigen Zeitpunkt die bestehende Vorgehensweise beibehalten werden sollte. Ebenso kann eine Abweichung von den festgelegten Sicherheiten nicht ausreichend abgesichert werden.
Zusammenführung von europäischen und deutschen Normen Eurocode 7, DIN 1054 und DIN 4020
Authors: Schuppener Bernd , Ruppert Franz‐Reinhard
Published: September 2007

Der Eurocode 7, “Entwurf, Berechnung und Bemessung in der Geotechnik”, liegt mit seinen beiden Teil en: DIN EN 1997‐1 “Allgemeine Regeln” und DIN EN 1997‐2 “Erkundung und Untersuchung des Baugrunds” seit September 2007 vollständig in deutscher Sprache vor. Der Inhalt dieser beiden Teil e des Eurocode deckt sich zum Teil mit zwei fundamentalen deutschen Normen der Geotechnik, DIN 1054:2005‐1 “Baugrund – Sicherheitsnachweise im Erd‐ und Grundbau” und DIN 4020:2003‐09 “Geotechnische Untersuchungen für bautechnische Zwecke”. Die Regeln der Europäischen Union verlangen, dass nach einer Kalibrierungsperiode von zwei Jahren und einer Koexistenzperiode von weiteren drei Jahren alle deutschen Normen zurückgezogen werden müssen, die Regelungen der Eurocodes enthalten. In etwa drei bzw. fünf Jahren werden daher DIN 1054 und DIN 4020 in der jetzigen Form nicht mehr gültig sein und durch überarbeitete Fassungen abgelöst werden. Es wird dargestellt, welche inhaltlichen und formalen Anpassungen für die zukünftigen deutschen geotechnischen Normen erforderlich werden und wie die in den deutschen Normen enthaltenen speziellen deutschen Erfahrungen im Erd‐ und Grundbau in das neue Normenwerk integriert werden.
Ein Ansatz zur versuchstechnischen Simulation und Übertragbarkeit der Hydroabrasion strömungsbeanspruchter Betonoberflächen im Wasserbau
Authors: Helbig Ulf , Horlacher Hans‐B.
Published: September 2007

An strömungsbeanspruchten Bauwerksoberflächen des konstruktiven Wasserbaus oder auch des Siedlungswasserbaus werden regelmäßig Schäden unterschiedlichster Art, insbesondere durch Hydroabrasion, beobachtet und in der Fachliteratur dargestellt und dokumentiert. Das im Folgenden beschriebene Verfahren stellt auf der Basis des Einsatzes von Abrasionstrommeln einen Ansatz zur versuchstechnischen Simulation und Übertragbarkeit verschiedener praktisch auftretender Abrasionsregimes dar. Hierbei ist wesentlich zu beachten, dass natürliche Fließgewässer unterschiedliche Einflussgrößen bezüglich vorhandener Fließgeschwindigkeiten, Geschiebezusammensetzungen und resultierender Feststofftransportraten aufweisen. Dies ist sowohl bei der Bemessung von Bauwerksoberflächen als auch bei der versuchstechnischen Replikation zu beachten.
The effect of mobile phone electromagnetic fields on the alpha rhythm of human electroencephalogram
Authors: Croft R.J. , Hamblin D.L. , Spong J. , Wood A.W. , McKenzie R.J. , Stough C.
Published: September 2007

Mobile phones (MP) emit low‐level electromagnetic fields that have been reported to affect neural function in humans; however, demonstrations of such effects have not been conclusive. The purpose of the present study was to test one of the strongest findings in the literature; that of increased “alpha” power in response to MP‐type radiation. Healthy participants (N = 120) were tested using a double‐blind counterbalanced crossover design, with each receiving a 30‐min Active and a 30‐min Sham Exposure 1 week apart, while electroencephalogram (EEG) data were recorded. Resting alpha power (8–12 Hz) was then derived as a function of time, for periods both during and following exposure. Non‐parametric analyses were employed as data could not be normalized. Previous reports of an overall alpha power enhancement during the MP exposure were confirmed (relative to Sham), with this effect larger at ipsilateral than contralateral sites over posterior regions. No overall change to alpha power was observed following exposure cessation; however, there was less alpha power contralateral to the exposure source during this period (relative to ipsilateral). Employing a strong methodology, the current findings support previous research that has reported an effect of MP exposure on EEG alpha power. Bioelectromagnetics 29:1–10, 2008. © 2007 Wiley‐Liss, Inc.
Some effects of a buried electricity transmission cable on bulk soil
Authors: Scalenghe Riccardo
Published: September 2007

A case study in NW Italy investigating an underground electric line (1 m depth triple cable at operative voltages 220–380 kV) measured electric fields in the surrounding soil virtually close to zero but magnetic fields (µTs) 20 times the background level. After 6 months, the influence radius around the cable on microbial activity (estimated by soil ATP), organic carbon, and total nitrogen follows exactly the inverse trend of the MF, shifting the biological activity with a lag distance of 5 m from the 220 kV cable. Bioelectromagnetics 28:667–671, 2007. © 2007 Wiley‐Liss, Inc.
An elementary metabolite unit (EMU) based method of isotopically nonstationary flux analysis
Authors: Young Jamey D. , Walther Jason L. , Antoniewicz Maciek R. , Yoo Hyuntae , Stephanopoulos Gregory
Published: September 2007

Nonstationary metabolic flux analysis (NMFA) is at present a very computationally intensive exercise, especially for large reaction networks. We applied elementary metabolite unit (EMU) theory to NMFA, dramatically reducing computational difficulty. We also introduced block decoupling, a new method that systematically and comprehensively divides EMU systems of equations into smaller subproblems to further reduce computational difficulty. These improvements led to a 5000‐fold reduction in simulation times, enabling an entirely new and more complicated set of problems to be analyzed with NMFA. We simulated a series of nonstationary and stationary GC/MS measurements for a large E. coli network that was then used to estimate parameters and their associated confidence intervals. We found that fluxes could be successfully estimated using only nonstationary labeling data and external flux measurements. Addition of near‐stationary and stationary time points increased the precision of most parameters. Contrary to prior reports, the precision of nonstationary estimates proved to be comparable to the precision of estimates based solely on stationary data. Finally, we applied EMU‐based NMFA to experimental nonstationary measurements taken from brown adipocytes and successfully estimated fluxes and some metabolite concentrations. By using NFMA instead of traditional MFA, the experiment required only 6 h instead of 50 (the time necessary for most metabolite labeling to reach 99% of isotopic steady state). Biotechnol. Bioeng. 2008;99: 686–699. © 2007 Wiley Periodicals, Inc.
Identification of age‐structured models: Cell cycle phase transitions
Authors: Sherer E. , Tocce E. , Hannemann R.E. , Rundell A.E. , Ramkrishna D.
Published: September 2007

A methodology is developed that determines age‐specific transition rates between cell cycle phases during balanced growth by utilizing age‐structured population balance equations. Age‐distributed models are the simplest way to account for varied behavior of individual cells. However, this simplicity is offset by difficulties in making observations of age distributions, so age‐distributed models are difficult to fit to experimental data. Herein, the proposed methodology is implemented to identify an age‐structured model for human leukemia cells (Jurkat) based only on measurements of the total number density after the addition of bromodeoxyuridine partitions the total cell population into two subpopulations. Each of the subpopulations will temporarily undergo a period of unbalanced growth, which provides sufficient information to extract age‐dependent transition rates, while the total cell population remains in balanced growth. The stipulation of initial balanced growth permits the derivation of age densities based on only age‐dependent transition rates. In fitting the experimental data, a flexible transition rate representation, utilizing a series of cubic spline nodes, finds a bimodal G0/G1 transition age probability distribution best fits the experimental data. This resolution may be unnecessary as convex combinations of more restricted transition rates derived from normalized Gaussian, lognormal, or skewed lognormal transition‐age probability distributions corroborate the spline predictions, but require fewer parameters. The fit of data with a single log normal distribution is somewhat inferior suggesting the bimodal result as more likely. Regardless of the choice of basis functions, this methodology can identify age distributions, age‐specific transition rates, and transition‐age distributions during balanced growth conditions. Biotechnol. Bioeng. 2008;99: 960–974. © 2007 Wiley Periodicals, Inc.
Purification of an acidic recombinant protein from transgenic tobacco
Authors: Holler Chris , Zhang Chenming
Published: September 2007

Tobacco has proven to be a promising alternative for the production of recombinant therapeutic proteins and offers numerous advantages over other plants as a host system. However, the recovery and purification steps needed to obtain a protein at high recovery and purity have not been well investigated. In this study, a process was developed to purify a model acidic protein, recombinant β‐glucuronidase (rGUS) from transgenic tobacco leaf tissue, in three main steps after extraction: polyelectrolyte precipitation, hydrophobic interaction chromatography (HIC), and hydroxyapatite chromatography (HAC). Using this three‐step process, up to 40% of the initial rGUS activity could be recovered to near homogeneity as judged by SDS–PAGE. This work demonstrates that acidic recombinant proteins expressed in tobacco may be purified to high yield with high purity in a minimal amount of steps that are suitable for scale‐up. Furthermore, the general steps used in this process may suggest that a wide variety of acidic recombinant proteins may be purified in a similar manner from transgenic tobacco or other leafy crops. Biotechnol. Bioeng. 2008;99: 902–909. © 2007 Wiley Periodicals, Inc.
Electrooptical measurements for monitoring metabolite fluxes in acetone–butanol–ethanol fermentations
Authors: Junne Stefan , Klein Eva , Angersbach Alexander , Goetz Peter
Published: September 2007

Anisotropy of electrical polarizability in Clostridium acetobutylicum cells during pH 5 controlled acetone butanol ethanol fermentations was observed. Cell length was determined from the electrooptical data. Mean length was determined as being 2.5 μm in the growth phase and 3.5 μm in the early stationary phase. Based on the obtained frequency dispersion of polarizability anisotropy (FDPA) in the range of 190 to 2,100 kHz, the switch from the acidogenic to the solventogenic phase could be monitored. The slope of polarizability versus the frequency made it possible to differentiate between phases of dominating acid and solvent production. Metabolite fluxes determined from concentration measurements correlated well to the polarizability. A partial least‐squares (PLS) model was established and validated by applying data from several fermentations. The root mean square error of calibration (RMSEC) was 0.09 for the acid fluxes and 0.11 for the solvent fluxes. The root mean square error of prediction (RMSEP) was 0.20 for acid fluxes and 0.24 for solvent fluxes. The ratio of polarizability at high and low frequencies correlated to the ongoing sporulation process. At ratios below 0.25, spore formation in the cells became visible under the microscope. The advantage of using electrooptical measurements is the ability to observe metabolite fluxes rather than concentrations, which provides useful information on productivity during a bioprocess. Biotechnol. Bioeng. 2008;99: 862–869. © 2007 Wiley Periodicals, Inc.
Silicon Analogues of the Retinoid Agonists TTNPB and 3‐Methyl‐TTNPB, Disila‐TTNPB and Disila‐3‐methyl‐TTNPB: Chemistry and Biology
Authors: Büttner Matthias W. , Burschka Christian , Daiss Jürgen O. , Ivanova Diana , Rochel Natacha , Kammerer Sabrina , Peluso‐Iltis Carole , Bindler Audrey , Gaudon Claudine , Germain Pierre , Moras Dino , Gronemeyer Hinrich , Tacke Reinhold
Published: September 2007

Twofold sila‐substitution (C/Si exchange) in the saturated ring of the tetrahydronaphthalene skeleton of the retinoid agonists TTNPB (1 a) and 3‐methyl‐TTNPB (2 a) leads to disila‐TTNPB (1 b) and disila‐3‐methyl‐TTNPB (2 b), respectively. The silicon compounds 1 b and 2 b were synthesized in multiple steps, and their identities were established by elemental analyses, multinuclear NMR experiments, and single‐crystal X‐ray diffraction studies. Like TTNPB (1 a) and 3‐methyl‐TTNPB (2 a), the analogous silicon‐based arotinoids 1 b and 2 b are strong pan‐RAR agonists and display the same strong differentiation and apoptosis‐inducing activity in NB4 promyelocytic leukemia cells as the parent carbon compounds. These results are in keeping with the nearly isomorphous structures of 1 a and 1 b bound to the complex of the RARβ ligand‐binding domain with the nuclear receptor (NR) box 2 peptide of the SRC‐1 coactivator. The contacts within the ligand‐binding pocket are identical except for helix H11, for which two turns are shifted in the disila‐TTNPB (1 b) complex. This study represents the first comprehensive structure–function analysis of a carbon/silicon switch in a signaling molecule and demonstrates that silicon analogues can have the same biological functionalities and conserved structures as their parent carbon compounds, and it illustrates at the same time that silicon analogues of biologically active compounds have the potential to induce alternative allosteric effects, as in the case of helix H11, which might allow for novel options in drug design.
Chiral recyclable dimeric and polymeric Cr(III) salen complexes catalyzed aminolytic kinetic resolution of trans‐aromatic epoxides under microwave irradiation
Authors: Kureshy Rukhsana I. , Prathap K. Jeya , Singh Surendra , Agrawal Santosh , Khan Noor‐Ul H. , Abdi Sayed H.R. , Jasra Raksh V.
Published: September 2007

Aminolytic kinetic resolution (AKR) of trans‐stilbene oxide and trans‐β‐methyl styrene oxide proceeded smoothly under microwave irradiation using chiral dimeric and polymeric Cr(III) salen complexes as efficient catalysts, giving regio‐, diastereo‐, and enantioselective anti‐β‐amino alcohols in high yields (49%) and chiral purity (ee up to 94%) in case of 4‐methylaniline within 2 min. The kinetic resolution system is approximately five times faster than traditional oil bath heating at 70°C and 420 times faster than the reaction conducted at room temperature with concomitant recovery of respective chirally enriched epoxides (ee, 92%) in excellent yields (up to 48%). The catalyst 1 worked well in terms of enantioselectivity than the catalyst 2, but both the catalysts were easily recovered and reused five times with the retention of its efficiency. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Physical foundations, models, and methods of diffusion magnetic resonance imaging of the brain: A review
Authors: Minati Ludovico , Węglarz Władysław P.
Published: September 2007

The foundations and characteristics of models and methods used in diffusion magnetic resonance imaging, with particular reference to in vivo brain imaging, are reviewed.

The first section introduces Fick's laws, propagators, and the relationship between tissue microstructure and the statistical properties of diffusion of water molecules. The second section introduces the diffusion‐weighted signal in terms of diffusion of magnetization (Bloch–Torrey equation) and of spin‐bearing particles (cumulant expansion). The third section is dedicated to the rank‐2 tensor model, the bb‐matrix, and the derivation of indexes of anisotropy and shape. The fourth section introduces diffusion in multiple compartments: Gaussian mixture models, relationship between fiber layout, displacement probability and diffusivity, and effect of the b‐value. The fifth section is devoted to higher‐order generalizations of the tensor model: singular value decompositions (SVD), representation of angular diffusivity patterns and derivation of generalized anisotropy (GA) and scaled entropy (SE), and modeling of non‐Gaussian diffusion by means of series expansion of Fick's laws. The sixth section covers spherical harmonic decomposition (SHD) and determination of fiber orientation by means of spherical deconvolution. The seventh section presents the Fourier relationship between signal and displacement probability (Q‐space imaging, QSI, or diffusion‐spectrum imaging, DSI), and reconstruction of orientation‐distribution functions (ODF) by means of the Funk–Radon transform (Q‐ball imaging, QBI). © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 278–307, 2007.
The standardized uptake value for F‐18 fluorodeoxyglucose is a sensitive predictive biomarker for cervical cancer treatment response and survival
Authors: Kidd Elizabeth A. , Siegel Barry A. , Dehdashti Farrokh , Grigsby Perry W.
Published: September 2007

BACKGROUND.

The objective of this study was to evaluate cervical tumor uptake of F‐18 fluorodeoxyglucose (FDG) measured as the maximal standardized uptake value (SUVmax) by positron emission tomography (PET) and its association with treatment response and prognosis in patients with cervical cancer.

METHODS.

The study population consisted of 287 patients with stage IA2 through IVB cervical cancer who underwent pretreatment FDG‐PET studies. SUVmax, tumor volume, and sites of lymph node metastasis were recorded. Therapy included surgery, chemoradiation, or palliation.

RESULTS.

The mean SUVmaxwas 11.4 (range, 1–50.4). The mean tumor volume by stage was 42.1 cm3for stage I tumors (using International Federation of Gynecology and Obstetrics [FIGO] staging criteria), 63.7 cm3for stage II tumors, 129.2 cm3for stage III tumors, and 166.2 cm3for stage IV tumors. There was no correlation between tumor volume and SUVmax(correlation coefficient [R2] = 0.01). No significant difference in SUVmaxwas observed between squamous histology (n = 247 patients) and nonsquamous histology (n = 40 patients;P= .089). Higher SUVmaxwas associated with an increased risk of lymph node metastasis at diagnosis (P= .0009). A Cox proportional‐hazards model for death from cervical cancer was used to evaluate tumor histology, lymph node metastasis, tumor volume, and SUVmax. The results indicated that SUVmaxwas the only significant independent factor (P= .0027). Three prognostic groups were established using SUVmax. The overall survival rates at 5 years were 95% for an SUVmax≤ 5.2, 70% for an SUVmax> 5.2 and ≤13.3, and 44% for an SUVmax> 13.3 (P< .0001). Increasing SUVmaxwas associated with persistent abnormal FDG uptake in the cervix on 3‐month FDG‐PET studies in 238 patients who received curative chemoradiation (P= .04).

CONCLUSIONS.

The SUVmaxof the cervical tumor at diagnosis was a sensitive biomarker of treatment response and prognosis for patients with cervical cancer. Cancer 2007. © 2007 American Cancer Society.
Hypermethylation, risk factors, clinical characteristics, and survival in 235 patients with laryngeal and hypopharyngeal cancers
Authors: Dikshit Rajesh P. , Gillio‐Tos Anna , Brennan Paul , De Marco Laura , Fiano Valentina , Martinez‐Peñuela Jose Maria , Boffetta Paolo , Merletti Franco
Published: September 2007

BACKGROUND.

It has been established that promoter hypermethylation occurs in several genes during the pathogenesis of head and neck cancer. The authors investigated the role played by the hypermethylation of 4 cancer‐related genes in the survival of patients who had laryngeal and hypopharyngeal cancer and in the occurrence of second primary tumors.

METHODS.

Archival paraffin‐embedded tissue (PET) samples were available from patients who were enrolled in a multicentric European case‐control study that was performed between 1979 and 1982 and was followed up to 2000. Genomic DNA extracted from 235 PET samples were analyzed for promoter methylation status of the p16, O6‐methylguanine‐DNA methyltransferase (MGMT), death‐associated protein kinase (DAP‐K), and E‐cadherin genes by using a methylation‐specific polymerase chain reaction assay.

RESULTS.

Hypermethylation was present in 44% of samples for p16, in 27% of samples for MGMT, in 42% of samples for DAP‐K, and in 43% of samples for E‐cadherin. Hypermethylation of either individual genes or their combination was not associated with mortality from all causes, mortality from upper aerodigestive tract cancer, or the occurrence of second primary tumors.

CONCLUSIONS.

The analysis of a large series of patients with laryngeal and hypopharyngeal cancer suggested that hypermethylation is a frequent event in laryngeal and hypopharyngeal cancer, but it is not a predictor of mortality or second primary cancer. Cancer 2007. © 2007 American Cancer Society.
Die neue Schallschutznormung – Zur Neufassung der DIN 4109
Authors: Pohlenz Rainer
Published: September 2007

Die im Jahre 1989 geborene Fassung der DIN 4109 ist in die Jahre gekommen. Dabei war es ihr leider nicht vergönnt, in Würde zu altern. Als Kind vieler zerstrittener Väter schon mit Geburtsfehlern zur Welt gekommen, kamen im Laufe der Jahre immer mehr Krankheiten ans Licht, von denen leider nicht alle geheilt werden konnten. So war es nur verständlich, dass sich sehr bald neue Eltern für eine neue Norm fanden, und viele Paten wurden ihnen zur Seite gestellt. Jedoch auch jetzt will es mit der Geburt nicht so recht klappen. Der Termin wird ein ums andere mal verschoben. Was war also krank an der alten Norm, und was muss die neue Norm besser machen?
Dinuclear Titanium(IV) Complexes Bearing Phenoxide‐Tethered N‐Heterocyclic Carbene Ligands with cisoid Conformation through Control of Hydrolysis
Authors: Zhang Dao
Published: September 2007

In situ generated N‐heterocyclic carbene salt derivative Na2(L) of 1,3‐bis(4,6‐di‐tert‐butyl‐2‐hydroxybenzyl)imidazolium bromide, [H3(L)]Br, reacted with 1 equiv. of TiBr4 at –78 °C to give a titanium complex of the composition [(L)TiBr2(thf)] (1), while the reaction in a 2:1 ratio under the same conditions afforded bisligand titanium complex [(L)2Ti] (2). Two oxygen‐bridged titanium dimers, {[(L)TiBr]2(μ‐O)} (4) and {[(L)Ti(μ‐O)]2} (5), were obtained by control of hydrolysis of 1 and [(L)Ti(CH2Ph)2] (3) in tetrahydrofuran and diethyl ether. The molecular structures of 2, 4, and 5 have been confirmed by X‐ray single‐crystal analysis. The phenoxide‐functionalized NHC ligand adopts transoid conformation in mononuclear complex 2 but rare cisoid conformation in dinuclear complexes 4 and 5. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Statement by the Editor, EurJIC
Authors: Hindson Karen
Published: September 2007

This Manuscript has been suspended pending investigation of potential unethical behavior. The header has been removed to protect innocent people. As soon as the investigation has been completed an official statement will be given at this site.
Fluorocycloalkylated Fullerenes in the Systems C60/70–C2F4I2
Authors: Pimenova Anna S. , Sidorov Lev N. , Kemnitz Erhard , Troyanov Sergey I.
Published: September 2007

An addition reaction of biradicals thermally generated from C2F4I2 was applied to functionalize fullerenes. This resulted in the formation of a number of C60(C2F4)n and C70(C2F4)m compounds. HPLC separation allowed the determination of the molecular structures of C60(C4F8)2 (two isomers), C60(C4F8)6, and C70(C2F4)2 and revealed that these compounds are formed by different modes of [4 + 2], [4 + 3], and [2 + 2] addition, respectively. A new synthetic approach for the preparation of a series of fluorocycloalkylated derivatives of fullerenes should be further exploited. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Investigation of the Role of Ionic Liquids in Imparting Electrocatalytic Behavior to Carbon Paste Electrode
Authors: Maleki Norouz , Safavi Afsaneh , Tajabadi Fariba
Published: September 2007

In this paper, a survey has been undertaken to clarify the possible reasons for the electrocatalytic activity obtained by the presence of ionic liquid in carbon paste electrode (CPE). For this purpose, the effect of the addition of traces of ionic liquid to conventional CPE was investigated. Fe(CN)63−/4− was used as a probe and two ionic liquids, namely n‐octylpyridinum hexafluorophosphate and 1‐octyl‐3‐methylimidazolium hexaflourophosphate were tested for their electrocatalytic activity. The reasons for this electrocatalytic behavior were evaluated and it was found that different factors such as increase in the ionic conduction of the binder, decrease in the resistance of the modified electrode, increase in ion exchange properties of the electrode and the inherent catalytic activity of ionic liquids are responsible for the considerable improved electrochemical response obtained in the presence of traces of ionic liquid.
Adsorptive Stripping Analysis of Riboflavin at Electrically Heated Graphite Cylindrical Electrodes
Authors: Wu Shao‐Hua , Sun Jian‐Jun , Lin Zhi‐Bin , Wu Ai‐Hong , Zeng Yong‐Ming , Guo Liang , Zhang De‐Feng , Dai Hui‐Ming , Chen Guo‐Nan
Published: September 2007

Electrically heated graphite cylindrical electrodes (HGCEs) made from ground pencil leads have been used to perform adsorptive stripping square wave voltammetry (SWV) measurements of trace riboflavin (RF). The SWV stripping peak current was significantly enhanced with increasing the electrode temperature only during preconcentration step. This enhancement was due to the forced thermal convection induced by heating the electrode rather than the bulk solution. It is the thermal convection that has the ability to improve mass transfer and facilitate adsorption thus enhance stripping responses. It was found that the detection limit of 5×10−9 M (S/N=3) could be obtained at an electrode temperature of 72 °C during 5 min accumulation, more than one magnitude lower than that at 22 °C (room temperature), the sensitivity could be enhanced ca. eight or four folds for two different RF concentration ranges. So it is possible to develop a new highly sensitive method to determine riboflavin at HGCEs. Such HGCEs were also successfully used to determine RF in multivitamin tablets.
Recent trends in CE of inorganic ions: From individual to multiple elemental species analysis
Authors: Timerbaev Andrei R.
Published: September 2007

The major methodological developments in CE related to inorganic analysis are overviewed. This is an update to a previous review article by the author (Timerbaev, A. R., Electrophoresis 2004, 25, 4008–4031) and it covers the review work and innovative research papers published between January 2004 and the first part of 2006. As was underlined in that review, a growing interest of analytical community in providing elemental speciation information found a sound response of the CE method developers. Presently, almost every second research paper in the field of interest deals with element species analysis, the use of inductively coupled plasma MS detection and biochemical applications being the topics of utmost research efforts. On the other hand, advances in general methodology traditionally centered on a CE system modernization for improvements in sensitivity and separation selectivity have attracted less attention over the review period. While there is no indication that inorganic ion applications would surpass by the developmental rate the more matured analysis of organic analytes, CE can now be seen as an analytical technique to be before long customary in a number of inorganic analysis arenas.
Study of the determination of inorganic arsenic species by CE with capacitively coupled contactless conductivity detection
Authors: Nguyen Huong Thi Anh , Kubáň Pavel , Pham Viet Hung , Hauser Peter C.
Published: September 2007

The determination of arsenic(III) and arsenic(V), as inorganic arsenite and arsenate, was investigated by CE with capacitively coupled contactless conductivity detection (CE‐C4D). It was found necessary to determine the two inorganic arsenic species separately employing two different electrolyte systems. Electrolyte solutions consisting of 50 mM CAPS/2 mM L‐arginine (Arg) (pH 9.0) and of 45 mM acetic acid (pH 3.2) were used for arsenic(III) and arsenic(V) determinations, respectively. Detection limits of 0.29 and 0.15 μM were achieved for As(III) and As(V), respectively by using large‐volume injection to maximize the sensitivity. The analysis of contaminated well water samples from Vietnam is demonstrated.
Differentiation of semantic dementia and Alzheimer's disease using the Addenbrooke's Cognitive Examination (ACE)
Authors: Davies R. Rhys , Dawson Kate , Mioshi Eneida , Erzinçlioğlu Sharon , Hodges John R.
Published: September 2007

Background

The Addenbrooke's Cognitive Examination (ACE) is a simple diagnostic tool bridging the gap between the very brief Mini Mental State Exam (MMSE) and much longer test batteries used by neuropsychologists which has proven extremely popular internationally.

Objective

We aimed to assess the ability of the ACE to differentiate semantic dementia (SD) from Alzheimer's disease (AD).

Methods

The ACE was administered to three groups: SD patients (n = 40) and two separate groups of AD patients (n = 40 in each), matched for overall ACE or MMSE score.

Results

Significant differences were found between SD and both AD groups for the ACE sub‐scores of naming, reading and orientation in time. Discriminant analysis (SD versus AD) led to the formulation of a ‘semantic index’ (naming plus reading minus scores for serial‐7s, orientation in time and drawing). Application of the semantic index to the patient data found values of less than zero to be predictive of SD rather than AD with 88% sensitivity and 90% specificity. Validation analysis in an independent sample of 24 SD and AD patients proved even more favourable.

Conclusions

The overall ACE score is known to be a sensitive, and specific, indicator of early neurodegenerative dementia; this study shows that the ACE can also be used to detect SD through application of the semantic index. Copyright © 2007 John Wiley & Sons, Ltd.
Swallowing disorders in the first year after radiation and chemoradiation
Authors: Logemann Jeri A. , Pauloski Barbara Roa , Rademaker Alfred W. , Lazarus Cathy L. , Gaziano Joy , Stachowiak Linda , Newman Lisa , MacCracken Ellen , Santa Daphne , Mittal Bharat
Published: September 2007

Background

Radiation alone or concurrent chemoradiation can result in severe swallowing disorders. This manuscript defines the swallowing disorders occurring at pretreatment and 3 and 12 months after completion of radiation or chemoradiation.

Methods

Forty‐eight patients (10 women and 38 men) participated in this study involving videofluorographic evaluation of oropharyngeal swallow at the 3 time points.

Results

At baseline, patients had some swallow disorders, probably related to presence of their tumor. At 3 months posttreatment, frequency of reduced tongue base retraction, slow or delayed laryngeal vestibule closure, and reduced laryngeal elevation increased from baseline. Some disorders continued at 12 months posttreatment. Functional swallow decreased over time in patients treated with chemoradiation, but not those treated with radiation alone.

Discussion

Chemoradiation results in fewer functional swallowers than radiation alone at 12 months posttreatment completion. © 2007 Wiley Periodicals, Inc. Head Neck, 2008
Spatial and temporal variability of the hydrological response in a small Mediterranean research catchment (Vallcebre, Eastern Pyrenees)
Authors: Latron J. , Soler M. , Llorens P. , Gallart F.
Published: September 2007

This paper analyses the spatial and temporal variability of the hydrological response in a small Mediterranean catchment (Cal Rodó). The first part of the analysis focuses on the rainfall–runoff relationship at seasonal and monthly scale, using an 8‐year data set. Then, using storm‐flow volume and coefficient, the temporal variability of the rainfall–runoff relationship and its relationship with several hydrological variables are analysed at the event scale from hydrographs observed over a 3‐year period. Finally, the spatial non‐linearity of the hydrological response is examined by comparing the Cal Rodó hydrological response with the Can Vila sub‐catchment response at the event scale. Results show that, on a seasonal and monthly scale, there is no simple relationship between rainfall and runoff depths, and that evapotranspiration is a factor that introduced some non‐linearity in the rainfall–runoff relationship. The analysis of monthly values also reveals the existence of a threshold in the relationship between rainfall and runoff depths, denoting a more contrasted hydrological response than the one usually observed in humid catchments. At the event scale, the storm‐flow coefficient has a clear seasonal pattern with an alternance between a wet period, when the catchment is hydrologically responsive, and a dry summer period, when the catchment is much less reactive to any rainfall. The relationship between the storm‐flow coefficient and rainfall depth, rainfall maximum intensity and base‐flow shows that observed correlations are the same as those observed for humid conditions, even if correlation coefficients are notably lower. Comparison with the Can Vila sub‐catchment highlights the spatial heterogeneity of the rainfall‐runoff relationship at the small catchment scale. Although interpretation in terms of runoff processes remains delicate, heterogeneities between the two catchments seem to be related to changes in the ratio between infiltration excess and saturation processes in runoff formation. Copyright © 2007 John Wiley & Sons, Ltd.
A note on estimating urban roof runoff with a forest evaporation model
Authors: Gash J. H. C. , Rosier P. T. W. , Ragab R.
Published: September 2007

A model developed for estimating the evaporation of rainfall intercepted by forest canopies is applied to estimate measurements of the average runoff from the roofs of six houses made in a previous study of hydrological processes in an urban environment. The model is applied using values of the mean rates of wet canopy evaporation and rainfall derived previously for forests and an estimate of the roof storage capacity derived from the data collected in the previous study. Although the model prediction is sensitive to the value of storage capacity, close correlation between the modelled and measured runoff indicates that the model captures the essential processes. It is concluded that the process of evaporation from an urban roof is sufficiently similar to that from a forest canopy for forest evaporation models to be used to give a useful estimate of urban roof runoff. Copyright © 2007 John Wiley & Sons, Ltd.