bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on the performance of different coiled column configurations for compact type‐I countercurrent chromatography
Authors: Yang Yi , Gu Dongyu , Aisa Haji Akber , Ito Yoichiro
Published: April 2011

Three types of novel coiled column configurations, i.e. a triangular coiled column and elliptical coiled columns I and II, were designed for type‐I countercurrent chromatography and their performances were evaluated with two solvent systems each with suitable test samples. Three dinitrophenyl (DNP) amino acids (DNP‐DL‐glu, DNP‐β‐ala and DNP‐L‐ala) were separated with a moderately hydrophobic two‐phase solvent system composed of hexane–ethyl acetate–metanol–0.1 M hydrochloric acid (1:1:1:1, v/v), while two dipeptides (tryptophyl‐tyrosine and valyl‐tyrosine) were separated with a polar solvent system composed of 1‐butanol–acetic acid–water (4.75:0.25:5, v/v). The overall results indicated that the performance of compact type‐I countercurrent chromatography was improved by elliptical coiled column I which was mounted with its maximum coil diameter perpendicular to the surface of the column holder. Hydrodynamic effects involved in these separations were discussed.
Synthesis and application of a novel molecularly imprinted polymer‐coated stir bar for microextraction of triazole fungicides in soil
Authors: Hu Yuling , Li Jiawei , Li Gongke
Published: April 2011

The preparation, characteristics and application of a sorptive stir bar coated with molecularly imprinted polymer (MIP) using triadimefon as the template molecule are described here. Raw glass capillary was coated with MIP through chemical bonding. The synthesis method was effective and reproducible with the batch‐to‐batch RSD within 7.8%. Scanning electron micrographs of the stir bar revealed a highly porous coating with average thickness of 15 μm. The synthesized stir bar was proved to be highly stable in most of the solvent for use. Extraction performance showed the fabricated stir bar has excellent molecular recognition abilities for triadimefon and the structure‐related compounds, such as triadimenol, diniconazole, flutriafol, hexaconazole, tebuconazole, paclobutrazol and uniconazole, and thus can be applied for simultaneous determination of these triazole fungicides from complex samples by coupling with high‐performance liquid chromatography. The variables that influence extraction were optimized with 10.0 μg/L standard solutions of triazole fungicides, and the analytical method was established for the determination of triazole fungicides in soil. The detection limits were in the range of 0.14–0.34 μg/L, and the recoveries were from 86.7 to 114.6% for spiked soil sample.
EPR Spectroscopy Provides a Molecular View on Thermoresponsive Dendronized Polymers Below the Critical Temperature
Authors: Junk Matthias J. N. , Li Wen , Schlüter A. Dieter , Wegner Gerhard , Spiess Hans W. , Zhang Afang , Hinderberger Dariush
Published: April 2011

The nanoscopic structure of thermoresponsive dendronized polymers below the critical aggregation temperature (TC) is revealed by CW EPR spectroscopy. At temperatures far below TC, the water‐swollen polymers start to dehydrate and hydrophobic cavities are formed. Two different dehydration processes can be discerned, the more effective of which is observed within 4 K below TC. The dehydration predominantly takes place at the peripheral dendritic shell, rendering it increasingly hydrophobic and eventually triggering an interchain aggregation and the formation of mesoglobules at the critical temperature. While the polymer aggregation is mainly dependent on the dendron periphery, the efficiency of the dehydration below TC is closely related to the hydrophobicity of the dendritic core.

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The Influence of Blend Morphology (Co‐Continuous or Sub‐Micrometer Droplets Dispersions) on the Nucleation and Crystallization Kinetics of Double Crystalline Polyethylene/Polyamide Blends Prepared by Reactive Extrusion
Authors: Córdova Miguel E. , Lorenzo Arnaldo T. , Müller Alejandro J. , Gani Léa , Tencé‐Girault Sylvie , Leibler Ludwik
Published: April 2011

Reactive blending of functionalized polyethylenes (PE) and polyamides (PA) is performed by carefully choosing extrusion conditions and polymeric materials in order to obtain two types of stable morphologies. The first blend type yields a co‐continuous morphology and the second type a dispersion of sub‐micron droplets of the PA phase in a PE matrix. The crystallization kinetics of the PA change from a sigmoidal classical type (for the co‐continuous blend) to first‐order kinetics in the case of the sub‐micron PA droplets. The results demonstrate an intimate relationship between blend morphology and nucleation and crystallization kinetics of the blend components.

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Synthesis and Photovoltaic Properties of a Poly(2,7‐carbazole) Derivative Based on Dithienosilole and Benzothiadiazole
Authors: Zhou Jiaoyan , Wan Xiangjian , Liu Yongsheng , Wang Fei , Long Guankui , Li Chenxi , Chen Yongsheng
Published: April 2011

A low bandgap poly(2,7‐carbazole) derivative PCDSBT containing dithienosilole and benzothiadiazole is synthesized by Stille polymerization. The incorporation of dithienosilole and carbazole causes PCDSBT to have a broad absorption from 350 to 800 nm and a relatively low HOMO level. Solar cell devices fabricated by blending PCDSBT with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) at a 1:2 weight ratio in a mixed solvent of 3% (by volume), 1,8‐diiodooctane, and 97% dichlorobenzene lead to a power conversion efficiency of 1.65% under the illumination of AM 1.5G (100 mW · cm−2).

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Biomimetic Route to Calcium Phosphate Coated Polymeric Nanoparticles: Influence of Different Functional Groups and pH
Authors: Schöller Katrin , Ethirajan Anitha , Zeller Anke , Landfester Katharina
Published: April 2011

The controlled synthesis of organic–inorganic hybrid particles with selective morphology using polymeric nanoparticles as templates offers an effective biomimetic route to design composite materials with interesting properties for various potential applications. In this study, the formation of hybrid particles via the bio‐inspired mineralization of calcium phosphate (CaP) on the surface of different surface‐functionalized polymeric nanoparticles is reported. The versatile miniemulsion polymerization is used to prepare different surface functionalized nanoparticles with covalently bound carboxylic acid and phosphonic acid surface‐functionalities. Functional comonomers with varying hydrophilicity like acrylic acid (AA), vinylphosphonic acid (VPA), and vinylbenzylphosphonic acid (VBPA) are employed for the copolymerization with styrene. The influence of different functional groups at different pH on the crystal phase and morphology of the calcium phosphate phase in the hybrid nanoparticles is analyzed in detail by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron as well as X‐ray diffraction (ED and XRD) techniques. The calcium ion binding affinity of different surface functional groups at varying loading conditions is studied using calcium ion selective electrode to shed light on the mineralization kinetics as well as on the interfacial chemistry involved between the complexing ions and the functional groups on the particle surface. The CaP/polymer hybrid particles with well‐defined crystal phases and morphologies offering varying surface topographies are interesting candidates for cell adhesion and proliferation studies for potential tissue engineering applications. They could be used as bone fillers, building blocks for the nucleation, and the growth of new bone material or implant coatings to reduce the immune response.

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Coordination Polymer Nanobelts as an Effective Sensing Platform for Fluorescence‐enhanced Nucleic Acid Detection
Authors: Li Hailong , Wang Lei , Zhai Junfeng , Zhang Yingwei , Tian Jingqi , Sun Xuping
Published: April 2011

In this communication, the application of coordination polymer nanobelts (CPNs) assembled from H2PtCl6 and 3,3′,5,5′‐tetramethylbenzidine (TMB) are explored as an effective fluorescent sensing platform for nucleic acid detection for the first time. The suggested method has a high selectivity down to single‐base mismatch. DNA detection is accomplished by the following two steps: (1) CPN binds fluorecent dye‐labeled single‐stranded DNA (ssDNA) probe via both electrostatic attraction and π‐π stacking interactions between unpaired DNA bases and CPN. As a result, the fluorescent dye is brought into close proximity to CPN and substantial fluorescence quenching occurs due to photoinduced electron transfer from the nitrogen atom in CPN to the excited fluorophore. (2) The hybridization of adsorbed ssDNA probe with its target generates a double stranded DNA (dsDNA). The duplex cannot be adsorbed by CPN due to its rigid conformation and the absence of unpaired DNA bases, leading to an obvious fluorescence enhancement.

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The Consumption of Oxygen and p‐Methoxyphenol in Acrylic Acid – Kinetics and Modeling
Authors: Brand Raphael H. , Hartwig A. , Opitz B. , Pfeifer C. , Drochner A. , Vogel G. Herbert
Published: April 2011

For a safe storage and handling of acrylic acid (AA), a lot of knowledge is necessary. In the present work, investigations were made in order to describe the stabilization processes during the inhibition period (IP) of AA more exactly. The oxygen and p‐methoxyphenol consumption was determined for AA at 70 and 80 °C in an enhanced parameter range and simulated with a kinetic model, using the software Presto Kinetics (R). In the simulation accelerated stabilizer consumptions at 80 °C could be confirmed. The known stabilization mechanism must be enhanced with autocatalytic steps, which lead to an accelerated stabilizer consumption. Furthermore, the stability of AA was examined as a function of the dissolved oxygen mass fraction and the temperature in isoperibolic reactors. The IP follows an Arrhenius behavior; therefore, an extrapolation from higher reaction temperatures to storage conditions is possible. These measurements also confirm the nonlinear stabilizer consumption during the IP at temperatures over 75 °C.

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Semibatch Aqueous‐Solution Polymerization of Acrylic Acid: Simultaneous Control of Molar Masses and Reaction Temperature
Authors: Minari Roque J. , Caceres Gerardo , Mandelli Paola , Yossen Mariana M. , Gonzalez‐Sierra Manuel , Vega Jorge R. , Gugliotta Luis M.
Published: April 2011

The semibatch polymerization of non‐ionized acrylic acid (AA) was investigated with the aim of producing poly(acrylic acid) (PAA) of controlled molar masses, at complete AA conversion, and under safe conditions. The proposed strategy mainly consists in feeding the AA at a constant rate along the reaction, for simultaneously controlling polymerization rate and molar masses. PAA of intermediate ${\bar {M}}_{{\rm n}} $, in the range 1 × 104–2 × 105 g · mol−1, was produced through an adequate selection of both the initiator concentration and the AA flow rate. In all experimental conditions, backbiting reactions were confirmed by 13C NMR. A simple mathematical model was developed to help interpret the experimental results.

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Catalytic Degradation of Polystyrene: Modeling of Molecular Weight Distribution
Authors: Gianoglio Pantano Ioana A. , Asteasuain Mariano , Díaz Mónica F. , Sarmoria Claudia , Brandolin Adriana
Published: April 2011

Two of the most abundant polymers in household waste streams, PS and PE, may be recycled by compatibilization through a Friedel‐Crafts alkylation. This reaction produces a graft copolymer PE‐g‐PS that improves the properties of the blend, but simultaneously degrades PS chains. Since the copolymer efficiency as a compatibilizer depends both on the molecular weight and MWD of its two blocks, the operating conditions for the copolymer synthesis must be carefully tuned. To aid in this task, we present a preliminary mathematical model that focuses on the effect of the catalyst and cocatalyst of the Friedel‐Crafts alkylation on the MWD of the PS chains. The model's predictions are shown to agree with experimental data.

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Topical naphazoline in the treatment of myasthenic blepharoptosis
Authors: Nagane Yuriko , Utsugisawa Kimiaki , Suzuki Shigeaki , Masuda Masayuki , Shimizu Yuko , Utsumi Hiroya , Uchiyama Shinichiro , Suzuki Norihiro
Published: April 2011

Introduction. When treating ocular myasthenia gravis (MG), the risk/benefit profile of corticosteroids is unclear, and acetylcholinesterase inhibitors are not very effective. We examined the efficacy of topical naphazoline in the treatment of myasthenic blepharoptosis. Methods. Sixty MG patients with blepharoptosis (32 with ocular symptoms only and 28 with mild generalized symptoms) were enrolled in a multicenter open trial of topical naphazoline. The effects were reported by patients via a questionnaire and were also confirmed for each patient at the clinic. Results. Among 70 eyes of 60 patients, 20 eyes (28.6%) of 17 patients (28.3%) exhibited a marked response (full eye opening), and 24 eyes (34.3%) of 20 patients (33.3%) showed a good response (adequate but incomplete eye opening). Topical naphazoline was evaluated as useful in the treatment of myasthenic blepharoptosis by >70% of the patients. Conclusions. Topical naphazoline was found to be an effective supplementary symptomatic treatment for myasthenic blepharoptosis. Muscle Nerve 44: 41–44, 2011.
Remote Hydrogen Microwave Plasma Chemical Vapor Deposition of Amorphous Silicon Carbonitride (a‐SiCN) Coatings Derived From Tris(dimethylamino)Silane
Authors: Wrobel Aleksander M. , Blaszczyk‐Lezak Iwona , Uznanski Pawel , Glebocki Bartosz
Published: April 2011

Amorphous silicon carbonitride films were produced by remote hydrogen plasma CVD (RP‐CVD) from Tris(dimethylamino)silane precursor. The effect of substrate temperature (TS) on the kinetics of RP‐CVD, chemical composition, structure, surface morphology, and properties of resulting films is reported. The TS dependence of film growth rate imply that RP‐CVD is an adsorption‐controlled process. The increase of TS from 30 to 400 °C causes the elimination of organic moieties from the film and the formation of SiC and SiN network structure. The structure–property relationships were determined. The films deposited at TS = 300 °C appear to be dense materials exhibiting very small surface roughness, high hardness, and an extremely low friction coefficient. They seem to be suitable protective coatings for metal surfaces to increase their wear strength.

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Fast approximations of the rotational diffusion tensor and their application to structural assembly of molecular complexes
Authors: Berlin Konstantin , O'Leary Dianne P. , Fushman David
Published: April 2011

We present and evaluate a rigid‐body, deterministic, molecular docking method, called ELMDOCK, that relies solely on the three‐dimensional structure of the individual components and the overall rotational diffusion tensor of the complex, obtained from nuclear spin‐relaxation measurements. We also introduce a docking method, called ELMPATIDOCK, derived from ELMDOCK and based on the new concept of combining the shape‐related restraints from rotational diffusion with those from residual dipolar couplings, along with ambiguous contact/interface‐related restraints obtained from chemical shift perturbations. ELMDOCK and ELMPATIDOCK use two novel approximations of the molecular rotational diffusion tensor that allow computationally efficient docking. We show that these approximations are accurate enough to properly dock the two components of a complex without the need to recompute the diffusion tensor at each iteration step. We analyze the accuracy, robustness, and efficiency of these methods using synthetic relaxation data for a large variety of protein‐protein complexes. We also test our method on three protein systems for which the structure of the complex and experimental relaxation data are available, and analyze the effect of flexible unstructured tails on the outcome of docking. Additionally, we describe a method for integrating the new approximation methods into the existing docking approaches that use the rotational diffusion tensor as a restraint. The results show that the proposed docking method is robust against experimental errors in the relaxation data or structural rearrangements upon complex formation and is computationally more efficient than current methods. The developed approximations are accurate enough to be used in structure refinement protocols. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Synthesis, characterization, and optical properties of Ag2Mo2O7 nanowires
Authors: Hashim Muhammad , Hu Chenguo , Chen Yanxue , Zhang Cuiling , Xi Yi , Xu Jing
Published: April 2011

Ag2Mo2O7 nanowires were synthesized by facile hydrothermal method from sodium molybdate and silver nitrate at temperature of 150 °C without any surfactant or template. The synthesized product was characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and transmission electron microscopy (TEM). It was found that the product is of anorthic phase and single crystalline nanowires with width of 200 nm and length up to 100 µm. UV–Visible reflection spectrum demonstrated a band gap of 2.94 eV. Photoluminescence (PL) spectrum exhibited strong violet emission centered at 412 nm and red emission ranging from 600 to 700 nm at room temperature. The greatly enhanced red emission was observed at low temperature. The emission mechanism has been discussed according to the calculated results of electron density of states (DOSs) for Ag2Mo2O7 with consideration of oxygen vacancies by using the Vienna ab initio simulation package (VASP).
XPS analysis and valence band structure of a low‐dimensional SiO2/Si system after Si+ ion implantation
Authors: Zatsepin D. A. , Mack P. , Wright A. E. , Schmidt B. , Fitting H.‐J.
Published: April 2011

A X‐ray photoelectron spectroscopy (XPS) of valence band (VB) and core levels are performed for a SiO2/p‐Si heterostructure containing a thin oxide layer of d = 20 nm thickness and implanted by Si+ ions. With an implantation energy of 12 keV the maximum density of the implanted Si+ profile is located close to the SiO2–Si interface at a depth of 18 nm, but a piling‐up of Si is also found immediately beneath the surface up to 2 nm, i.e., within the escape depth of XPS electrons. Thus we may expect a partial phase separation associated with Si aggregation and nanocluster formation imbedded in a non‐stoichiometric SiOx matrix. By means of XPS and in comparison to X‐ray emission spectroscopy (XES) the related changes of the VB structure are investigated.
Fragmentation of xanthene dyes by laser activation and collision‐induced dissociation on a high‐resolution Fourier transform ion cyclotron resonance mass spectrometer
Authors: Peters Jonathan , Grotemeyer Jürgen
Published: April 2011

Surprising fragmentation reactions in different xanthene dyes have been investigated by means of photodissociation and collision‐induced dissociation in a 9.4 T FT‐ICR mass spectrometer. It is shown that extensive rearrangement reactions lead to the formation of unexpected fragments which are identified for the first time by the use of high resolving mass power. The observed reactions are an example of the fragmentation of a quinoidal even‐electron cation. Copyright © 2011 John Wiley & Sons, Ltd.
Determination of aflatoxins in animal feeds by liquid chromatography/tandem mass spectrometry with isotope dilution
Authors: Li Wei , Herrman Timothy J. , Dai Susie Y.
Published: April 2011

The objective of the present study is to develop a simple, fast method for detection of aflatoxins in animal feeds. Simultaneous quantitation of four aflatoxins (AFB1, AFB2, AFG1 and AFG2) in animal feeds was achieved in a single liquid chromatography/tandem mass spectrometry (LC/MS/MS) run. The solid‐phase extraction cleanup step is eliminated with the stable isotope dilution method. Matrix effects were observed and overcome by isotope dilution. The method was tested in a variety of animal feed matrices and proved to be accurate and reliable. Method ruggedness tests resulted in recoveries of 78% to 122% with an intra‐day assay precision of 2% to 15% and an inter‐day assay precision of 3% to 17%. These results indicate that this method is suitable for quantitation of aflatoxins in animal feeds. Copyright © 2011 John Wiley & Sons, Ltd.
Fragmentation pathways of oxygenated tetracyclic triterpenoids and their application in the qualitative analysis of Ganoderma lucidum by multistage tandem mass spectrometry
Authors: Cheng Chun‐Ru , Yang Min , Wu Zhi‐Yuan , Wang Yang , Zeng Feng , Wu Wan‐Ying , Guan Shu‐Hong
Published: April 2011

The fragmentation pathways of oxygenated tetracyclic triterpenoids from Ganoderma lucidum were systematically studied based on interpreting the mass spectra of 44 known triterpenoids using a combination of multistage tandem mass spectrometry (MSn) experiments and high‐resolution mass spectrometry (HRMS) analysis. In negative ion mode, the fragmentation pathways of triterpenoid acids are rather characteristic. After the prominent loss of H2O or CO2, cleavages take place on the A, B, C and D rings. Interestingly, the cleavage mode is highly dependent on the positions of the carbonyl groups and hydroxyl groups in the tetracyclic skeleton. Characteristic cleavage of ring A occurs in 7‐oxo‐11‐H or 7‐oxo‐11‐hydroxy derivatives; characteristic cleavage of ring B occurs in the 7‐oxo‐11‐hydroxy derivatives; characteristic cleavage of ring C occurs in the 7‐hydroxy‐15‐oxo derivatives; while the cleavage of ring D can be observed in the majority of the compounds investigated. The odd‐electron species, which disobey the ‘even‐electron rule’, are also observed and discussed in this paper. These phenomena provide an easy way to determine the tetracyclic skeleton and distinguish the isomers of the triterpenoids from each other. What is more, the fragmentation pathways of triterpenoid alcohols were also investigated in positive ion mode. The accurate masses of the product ions were determined using quadrupole orthogonal time‐of‐flight (QTOF) instruments. Finally, the fragmentation rules were applied to identify the components of G. lucidum. As a result, 73 triterpenoids including 11 new ones were identified. The triterpenoids were classified into six subclasses according to their different fragmentation behaviors. The application of tandem mass spectrometry was further explored. Copyright © 2011 John Wiley & Sons, Ltd.
Density functional theory study of BnC clusters
Authors: Liu Chunhui , Han Peilin , Tang Mingsheng
Published: April 2011

BnC clusters (n = 3–10) were studied at the density functional theory (DFT) (B3LYP)/6‐311G** level of theory. The calculations predicted that the most stable configurations of the BnC clusters are the (n + 1)‐membered cyclic structures. For boron–carbon clusters, the configurations containing greater numbers of three‐membered boron rings are more favorable, except for the B7C and B9C clusters. Through molecular orbital analysis of these BnC clusters, we have concluded that π‐electron delocalization plays a crucial role in the stability of n + 1‐membered cyclic structures. In this paper, the relative stability of each cluster is discussed based on their single atomic‐binding energies. The capability of clusters to obtain or lose an electron was also discussed, based on their vertical electron detachment energies (VDEs), adiabatic electron detachment energies (ADEs), vertical electron affinities (VEAs) and adiabatic electron affinities (AEAs). Copyright © 2011 John Wiley & Sons, Ltd.
Detection of illicit drugs on surfaces using direct analysis in real time (DART) time‐of‐flight mass spectrometry
Authors: Grange Andrew H. , Sovocool G. Wayne
Published: April 2011

Methamphetamine (meth) from meth syntheses or habitual meth smoking deposited on household surfaces poses human health hazards. The U.S. State Departments of Health require decontamination of sites where meth was synthesized (meth labs) before they are sold. National Institute for Occupational Safety and Health (NIOSH) methods for meth analysis require wipe sampling, extraction, clean‐up, solvent exchange, derivatization, and/or mass spectral analysis using selected ion monitoring. Rapid and inexpensive analyses could screen for drug‐contamination within structures with greater spatial resolution, provide real‐time analyses during decontamination, and provide thorough documentation of successful clean ups. Herein an autosampler/open‐air ion source time‐of‐flight mass spectrometric technique is described that required only direct sampling using cotton‐swab wipes. Each wipe sample collection required 2 min and data acquisition required only 13 s per sample. Optimum collision‐induced dissociation voltages, desorption gas temperatures, and wipe sample solvents were determined for 11 drugs. Peaks were observed in analyte‐ion traces for 0.025 µg/100 cm2 of meth and seven other drugs. This level is half the detection limit of NIOSH methods and one‐fourth of the lowest U.S. state decontamination limit for meth. Dynamic ranges of 100 in concentration were demonstrated for eight drugs, which is sufficient for a screening technique. The volatilities of 11 drugs deposited on glass were determined. The pick up of the drugs by solvent‐soaked cotton‐swab wipes from glass relative to acrylic latex paint was also compared. Published in 2011 by John Wiley & Sons, Ltd.
Encoding of stoichiometric constraints in the composition depth profile reconstruction from angle resolved X‐ray photoelectron spectroscopy data
Authors: Macak Karol
Published: April 2011

The inversion of angle resolved XPS data is a difficult problem, due to mathematical complexity of accurate model of electron transport, sensitivity to noise and small number of measured points limiting the depth resolution and the accuracy of the calculated depth profiles. Extended maximum entropy model for the calculation of apparent compositions (measured intensity ratios) is presented which allows to encode linear relationship between element concentrations. These can be used to calculate a solution with additional stoichiometric relationships and analyze, simultaneously, signals from several synthetic peak components. The synthetic peak components used in the model can represent various core level energy shifts, which are otherwise difficult to determine unambiguously from the measured signal. Element concentrations linked with stoichiometric relationships are used to identify compound materials with known density and inelastic scattering properties. The new model, thus allows self‐consistent recovery of depth profiles using maximum entropy method without the assumption of homogeneous density. The improved accuracy of the recovered depth profiles is demonstrated on the analysis of HfON/SiON overlayers. Various artefacts in the depth profiles obtained with standard maximum entropy model, which assumes constants density are identified. Copyright © 2011 John Wiley & Sons, Ltd.
Silane grafting of TiO2 nanoparticles: dispersibility and photoactivity in aqueous solutions
Authors: Pazokifard Sh. , Mirabedini S. M. , Esfandeh M. , Mohseni M. , Ranjbar Z.
Published: April 2011

Titania nano‐sized particles were treated by various amounts of tetraethyl orthosilicate precursor. The extent of grafting was characterized using Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐Vis) spectroscopy techniques, thermal gravimetric analysis, X‐ray fluorescence and zeta potential measurements. Sedimentation behaviour of titanium dioxide (TiO2) nanoparticles in aqueous solutions was evaluated visually and using a separation analyser. Photocatalytic activity of nanoparticles was studied by photo‐activated degradation reaction of Rhodamine B dyestuff in aqueous solutions. The results showed that grafted particles had acquired enhanced dispersion stability and lower photocatalytic activity in aqueous solutions. Untreated TiO2 dispersions settled rapidly and sedimentation completed within 24 h through the coagulation mechanism, whereas that of the silica‐treated nanoparticles, depending on the silica content, showed different degrees of stability by flocculation mechanism. Photodebleaching of Rhodamine B in the presence of treated nanoparticles is evident by weaker intensity of UV absorption peak of 554 nm due to lowering concentration of Rhodamine B accompanied with the blue shift in UV absorption peaks. However, untreated TiO2 nanoparticles showed only weaker intensity of UV absorption peak. Copyright © 2011 John Wiley & Sons, Ltd.
Interaction between model poly(ethylene terephthalate) thin films and weakly ionised oxygen plasma
Authors: Doliška Aleš , Vesel Alenka , Kolar Metod , Stana‐Kleinschek Karin , Mozetič Miran
Published: April 2011

Model films of poly(ethylene terephthalate) were treated by oxygen plasma in order to quantify the etching rate and estimate the contribution of charged and neutral particles to the reaction probability. Model films with a thickness of 50 nm were deposited on a quartz crystal of a microbalance (QCM) by spin‐coating technique. The samples were exposed to oxygen plasma with the positive ion density of 4 × 1015 m−3 and neutral oxygen atom density of 6 × 1021 m−3. The etching rate was determined from the QCM signal and was 4.7 nm s−1. The etching was found rather inhomogeneous as the atomic force microscopic images showed an increase of the surface roughness as a result of plasma treatment. The model films were completely removed from the surface of the quartz crystals in about 12 s. Knowing the etching rate and the flux of oxygen atoms to the surface allowed for calculation of the reaction probability which was found to be rather low at the value of 1.6 × 10−4. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of Influencing Factors on Distribution Behaviors of Vanadium between Hot Metal and FeO‐SiO2‐MnO (‐TiO2) Slag System
Authors: Zhang Y. L. , Zhao F. , Wang Y. G.
Published: April 2011

The distribution behavior of vanadium between a hot metal and a FeO‐SiO2‐MnO (‐TiO2) slag system was studied under laboratory conditions, together with the effects of influencing factors such as temperature, slag composition, the ratio of slag to hot metal, and the initial Si and/or Ti content in hot metal. The results suggested that in a ternary FeO‐SiO2‐MnO slag system, with an increase in temperature and an increase in the SiO2 content of slag, the extraction ratio ($\eta _{V} $), distribution ratio of V ($L_{V} $) and the vanadium capacity of the slag ($C_{VO_{3} {}^{3{-} } } $) decreased, while the effect of MnO content in slag showed a different tendency under different situations. For both high and low ratios of slag to hot metal, the extraction ratio of V reached its maximum value under slag compositions of 13%–25% MnO and 10%–24% SiO2, which correspond to the regions with lower melting point and lower viscosity of the slag. In a quaternary FeO‐SiO2‐MnO‐TiO2 slag system,$\eta _{V} $,$L_{V} $, and $C_{VO_{3} {}^{3{-} } } $ decreased, while the activity coefficient of V2O3 increased, as the TiO2 content increased. Further, the data suggested that under laboratory conditions the effects of influencing factors on the extraction ratio of V from hot metal decreased in the following order: final slag composition > temperature > initial Si and/or Ti content in hot metal.
A lvt‐type Framework [Cu2(tza)4]·ClO4·4H2O Derived from 1H‐tetrazole‐1‐acetic Acid
Authors: Ma Li , Peng Guo , Cai Jin‐Biao , Deng Hong , Zeller Matthias
Published: April 2011

The reaction of 1H‐tetrazole‐1‐acetic acid (Htza) and perchloric acid with cuprous chloride with slow evaporation at room temperature gave a novel 3D porous CuII coordination polymer, [Cu2(tza)4]·ClO4·4H2O (1), (tza = tetrazole‐1‐acetate). The structure exhibits an unusual 3D microporous coordination framework built up by four coordinated CuII nodes and bidentate bridging tza ligands with lvt‐type topology. Furthermore, the magnetic properties of complex 1 were also investigated.
Polymorph of Dibenzo‐24‐Crown‐8 and its Mercury Complex
Authors: Crochet Aurelien , Kottelat Emmanuel , Fleury Antoine , Neuburger Markus , Fromm Katharina M.
Published: April 2011

Dibenzo‐24‐crown‐8 is studied herein as a flexible ligand able to adopt different conformations, as well as for the complexation of mercury. The recrystallization of dibenzo‐24‐crown‐8 (DB24C8) from dry THF gives a new polymorphic structure of this ligand. This new structure is described and compared to the literature compound. Additionally, coordination of this ligand to mercury iodide HgI2 is studied.
Dietary dilemmas in the management of glycogen storage disease type I
Authors: Bhattacharya Kaustuv
Published: April 2011

Over the last 50 years, understanding the biochemical bases of glycogen storage disease type I has led to vastly improved survival and health outcomes but the management still centres around an extremely intensive dietary regimen. Patients’ metabolic profiles are really determined by the whole of the diet and it can be very difficult to adjust therapy accordingly. In an iso‐energetic diet with reference total energy intake, high carbohydrate intake could compromise other macro‐ and micro‐nutrients; if carbohydrates are not restricted then total energy intake is excessive. The quality of the macronutrient such as the glycemic index of carbohydrate, the type of sugar and the proportion of medium–chain triglyceride and essential fatty acids also has a bearing on an individual's long‐term metabolic control with potential clinical correlates. These factors as well as the different requirements between individuals and within individuals as they get older mean that the management of glycogen storage disease type I is particularly fraught. Regular clinical and dietary review is imperative as patients grow, ensuring adequate but not excessive low glycaemic index carbohydrate intake, appropriate dynamic biochemical profiles and suitable age appropriate eating patterns. Without diligent management, and education that empowers the patient, these individuals can struggle in adult life.
Extended Family Impact of Genetic Testing: The Experiences of X‐linked Carrier Grandmothers
Authors: Lehmann Anna , Speight Beverley S. , Kerzin‐Storrar Lauren
Published: April 2011

In many cases, X‐linked conditions are transmitted through families “silently” until the first affected individual is diagnosed. Grandmothers are often then tested to help determine the risk to other family members. To date, psychosocial research on carriers of X‐linked conditions has focused primarily on mothers and sisters of affected males. In the wider social science literature, studies on grandparents of children with disabilities have centered on their role within the family and relationship with the grandchild. We therefore know little about the impact of carrier testing for a genetic condition on grandparents. This qualitative study aims to contribute towards filling that gap. This study included thirteen grandmothers in families with Fragile X or Duchenne muscular dystrophy; ten had living affected grandsons and three had daughters who chose not to continue with affected male pregnancies after prenatal diagnosis. All thirteen took part in semi‐structured interviews and provided a rich and varied data source for conducting thematic analysis. Most of the grandmothers expressed recurring feelings of guilt and a strong sense of responsibility for what had occurred in the family. Other themes included feelings of shock after receiving their test result, changes in family relationships and searching to make sense of the inheritance within the context of the family's experience. This study provides evidence that X‐linked carrier testing can have a profound and lasting impact on grandmothers. Although genetic counseling for X‐linked conditions is often focused on the potential reproductive implications for carriers, these findings suggest that grandmothers should also be offered genetic counseling when tests are carried out, because of the likely psychosocial impact of a positive test result.
Unique bioactivities of bone morphogenetic proteins in regulation of reproductive endocrine functions
Authors: Otsuka Fumio , Inagaki Kenichi
Published: April 2011

Remarkable progress has been made in understanding the mechanism by which growth factors and oocytes can regulate the development and function of granulosa cells. Insufficiency of two oocyte‐specific growth factors, growth differentiation factor‐9 and bone morphogenetic protein (BMP)‐15, cause female infertility. Expression of mRNA and/or protein for the BMP system components, including ligands, receptors and intracellular signal transduction factors, was demonstrated in cell components of growing preantral follicles, and biofunctional experiments have further revealed many important roles of the BMP system in regulation of reproductive function. In this review, recent advances in studies on biological actions of BMPs in ovarian folliculogenesis and in related endocrine tissues are discussed.
Common primary tumours of the abdomen and pelvis and their patterns of tumour spread as seen on multi-detector computed tomography
Authors: Griffin Nyree , Burke Christopher , Grant Lee Alexander
Published: April 2011

Background

Multidetector computed tomography (MDCT) has become the main investigation of choice for staging of many cancers.

Aim

The purpose of this pictorial review is to discuss the imaging appearances on CT of some of the more common cancers arising within the abdomen and pelvis and to describe their typical sites of local, nodal and haematogenous tumour spread.

Methods

Cancers arising from the stomach, pancreas, colon, kidney, ovary and prostate will be reviewed.

Results

Awareness of the characteristic sites of tumour spread is important to allow accurate identification of all sites of disease.

Conclusion

This will clearly have an impact on both patient management and prognosis.
Familial Influences on Poverty Among Young Children in Black Immigrant, U.S.-born Black, and Nonblack Immigrant Families
Authors: Thomas Kevin J. A.
Published: April 2011

This study examines how familial contexts affect poverty disparities between the children of immigrant and U.S.-born blacks, and among black and nonblack children of immigrants. Despite lower gross child poverty rates in immigrant than in U.S.-born black families, accounting for differences in family structure reveals that child poverty risks among blacks are highest in single-parent black immigrant families. In addition, within two-parent immigrant families, child poverty declines associated with increasing assimilation are greater than the respective declines in single-parent families. The heads of black immigrant households have more schooling than those of native-black households. However, increased schooling has a weaker negative association with child poverty among the former than among the latter. In terms of racial disparities among the children of immigrants, poverty rates are higher among black than nonblack children. This black disadvantage is, however, driven by the outcomes of first-generation children of African and Hispanic-black immigrants. The results also show that although children in refugee families face elevated poverty risks, these risks are higher among black than among nonblack children of refugees. In addition, the poverty-reducing impact associated with having an English-proficient household head is about three times lower among black children of immigrants than among non-Hispanic white children of immigrants.
Vitamin B6: a challenging link between nutrition and inflammation in CVD
Authors: Lotto Valentina , Choi Sang-Woon , Friso Simonetta
Published: April 2011

The objective of the present review is to highlight the relationship between low vitamin B6status and CVD through its link with inflammation. While overt vitamin B6deficiency is uncommon in clinical practice, increasing evidence suggests that marginal vitamin B6deficiency is rather frequent in a consistent proportion of the population and is related to an increased risk of inflammation-related diseases. Ample evidence substantiates the theory of atherosclerosis as an inflammatory disease, and low plasma vitamin B6concentrations have been related to increased CVD risk. Several studies have also shown that low vitamin B6status is associated with rheumatoid arthritis and chronic inflammatory bowel diseases, both of which hold an underlying chronic inflammatory condition. Furthermore, the inverse association observed between inflammation markers and vitamin B6supports the notion that inflammation may represent the common link between low vitamin B6status and CVD risk. In addition to the epidemiological evidence, there are a number of cell culture and animal studies that have suggested several possible mechanisms relating impaired vitamin B6status with chronic inflammation. A mild vitamin B6deficiency characterises, in most cases, a subclinical at-risk condition in inflammatory-linked diseases which should be addressed by an appropriate individually tailored nutritional preventive or therapeutic strategy.
Testes of obese rats are highly responsive ton-3 long-chain fatty acids
Authors: Suh Miyoung , Merrells Krystal J. , Dick Amy , Taylor Carla G.
Published: April 2011

The present study investigated whether fatty acid compositions of testes are affected by the obese condition and dietaryn-3 long-chain fatty acid (LCFA) intake. Male lean and obese Zucker rats were fed a 15 % (w/w, total diet) fat diet containing either 0 or 5·0 % (w/w, total fatty acids)n-3 LCFA for 8 weeks. Reproductive organ weights, sperm morphology and fatty acid composition of phosphatidylcholine (PC), and phosphatidylethanolamine (PE) of testes were analysed. The obese rats had significantly (P < 0·0001) smaller epididymides and seminal vesicles, larger prostates and abundant underdeveloped testes compared with lean rats. Diet treatment did not affect the sex organ weights. The effect of genotype on fatty acid composition was minor in PC and PE except for DHA (22 : 6n-3). Then-3 LCFA diet significantly (P < 0·0001) elevated 22 : 6n-3 and reduced arachidonic acid (20 : 4n-6) and DPA (22 : 5n-6) in testicular PC and PE of lean and obese rats compared with the control diet. The acylation of dietaryn-3 LCFA into 22 : 6n-3 was 2-fold higher in obese rat testes than in lean rats fed the same diet. Underdeveloped testes had 70 % less 22 : 5n-6 in PC and PE than normal-size testes. Results indicate that testicular fatty acid composition is sensitive to dietary fat modulations and especially obese rats responded more to dietaryn-3 LCFA than their lean counterparts. The selective reduction in 22 : 5n-6 in underdeveloped testes indicates that 22 : 5n-6 is important in male reproduction in rats and requires further study to define the role of elongation and desaturation in testicular development.
Modified endotracheal tube: emergency alternative to paediatric tracheostomy tube
Authors: Kurien M , Raviraj R , Mathew J , Kaliaperumal I , Ninan S
Published: April 2011

Background:

In an emergency, the non-availability of a conventional paediatric tracheostomy tube is a therapeutic challenge for the attending surgeon.

Objective:

To describe a simple alternative to a paediatric tracheostomy tube for use in an emergency situation.

Method:

Case report of a 14-year-old boy who developed tracheomalacia following partial cricotracheal resection for subglottic stenosis. As a suitably sized tracheostomy tube (with a long narrow segment) was not available, an endotracheal tube was modified and used successfully. Details of the modification, and a relevant literature review, are also discussed.

Conclusion:

In the paediatric age group, when an appropriately sized tracheostomy tube is not available, a modified endotracheal tube is a simple temporary alternative; this may be especially useful in an emergency.
Numerical simulations to study whistler turbulence by kinetic Alfvén wave
Authors: SHARMA R. P. , BATRA K. , DWIVEDI N. K.
Published: April 2011

This work presents the model equations governing the excitation of weak whistler by a stronger Kinetic Alfvén wave (KAW) in the plasma having β value (β ≫ me/mi, where beta is the ratio of the ion sound speed to the Alfvén speed), applicable to magnetotail in Earth's magnetosphere, when the ponderomotive nonlinearity is incorporated in the KAW dynamics. Numerical solution of the model equations has been obtained when the incident pump KAW is having a small perturbation. Energy exchange between main KAW and perturbation and the resulting localized structures of the KAW have been studied. A weak whistler signal propagating in these localized structures is amplified and leads to the development of envelope solitons. Our result reveals that the amplified (excited) whistler has an electric field power spectrum that is steeper than k−8/3. This result is consistent with recent observations by the Cluster spacecraft Eastwood et al. (Phys. Rev. Lett., vol. 102, 2009, 035001) in the magnetotail region of the Earth's magnetosphere.
Minors in Graphs with High Chromatic Number
Authors: BÖHME THOMAS , KOSTOCHKA ALEXANDR , THOMASON ANDREW
Published: April 2011

We develop lower bounds on the Hadwiger number h(G) of graphs G with high chromatic number. In particular, if G has n vertices and chromatic number k then h(G) ≥ (4k − n)/3.
Upper and Lower Extremity Motor Function and Cognitive Impairment in Multiple Sclerosis
Authors: Benedict Ralph H.B. , Holtzer Roee , Motl Robert W. , Foley Frederick W. , Kaur Sukhmit , Hojnacki David , Weinstock-Guttman Bianca
Published: April 2011

Motor impairments and cognitive dysfunction are common in multiple sclerosis (MS). We aimed to delineate the relationship between cognitive capacity and upper and lower motor function in 211 MS patients, and 120 healthy volunteers. Lower and upper motor function were assessed with the Timed 25 Foot Walk (T25FW) and the Nine Hole Peg Test (NHPT) as implemented in the Multiple Sclerosis Functional Composite (MSFC). Subjects also underwent neuropsychological evaluation. Hierarchical linear regression analysis was conducted separately for the MS and healthy groups with the T25FW and NHPT serving as the outcome measures. Cognitive performance indices served as predictors. As expected, healthy subjects performed better than the MS group on all measures. Processing speed and executive function tests were significant predictors of lower and upper motor function in both groups. Correlations were more robust in the MS group, where cognitive tests predicted variability in motor function after controlling for disease duration and physical disability. In conclusion, we find evidence of higher order cognitive control of motor function that appears to be particularly salient in this large and representative MS sample. The findings may have implications for risk assessment and treatment of mobility dysfunction in MS. (JINS, 2011, 17, 643–653)
LIQUIDITY PROVISION IN CAPACITY-CONSTRAINED MARKETS
Authors: Weill Pierre-Olivier
Published: April 2011

We study a competitive dynamic financial market subject to a transient selling pressure when market makers face a capacity constraint on their number of trades per unit of time with outside investors. We show that profit-maximizing market makers provide liquidity in order to manage their trading capacity constraint optimally over time: they use slack trading capacity early to accumulate assets when the selling pressure is strong in order to relax their trading capacity constraint and sell to buyers more quickly when the selling pressure subsides. When the trading capacity constraint binds, the bid–ask spread is strictly positive, widening and narrowing as market makers build up and unwind their inventories. Because the equilibrium asset allocation is constrained Pareto-optimal, the time variations in bid–ask spread are not a symptom of inefficient liquidity provision.