bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular biology, phytochemistry and bioactivity of three endemic Aloe species from Mauritius and Réunion Islands
Authors: Ranghoo‐Sanmukhiya Mala , Govinden‐Soulange Joyce , Lavergne Christophe , Khoyratty Shannoo , Da Silva Denis , Frederich Michel , Kodja Hippolyte
Published: September 2010

Introduction – Aloe tormentorii, A. purpurea and A. macra are used as multipurpose folk medicines in Réunion and Mauritius Islands and are mistaken for the introduced Aloe vera.

Objective – To compare the phytochemical, antimicrobial and DNA profiles of Aloe endemic to Mauritius and Réunion with the profiles of A. vera.

Methodology – Leaf extracts of these Aloe species were analysed using standard phytochemical screening techniques, TLC and by HPLC. These extracts were also assayed for antimicrobial activity using microdilution techniques. Genetic diversity was studied using RAPD markers.

Results – Phytochemical and antimicrobial assays and RAPD analysis showed that Mascarene Aloe species were very different from A. vera.

Conclusion – This study is the first report highlighting the differences between Aloe sp.p from Mascarene and Aloe vera at the metabolic and genomic level. Copyright © 2010 John Wiley & Sons, Ltd.
Development of an LC‐MS method for simultaneous quantitation of amentoflavone and biapigenin, the minor and major biflavones from Hypericum perforatum L., in human plasma and its application to real blood
Authors: Michler Hans , Laakmann Gregor , Wagner Hildebert
Published: September 2010

Introduction – Biflavones of Hypericum perforatum L. are bioactive compounds used in the treatment of inflammation and depression. Determination of amentoflavone and biapigenin from blood is challenging owing to their similar structures and low concentrations.

Objective – To develop a rapid, sensitive and accurate method based on liquid‐phase extraction followed by high‐performance liquid chromatography and electrospray ionisation mass spectrometry (HPLC‐ESI‐MS) for quantification of biflavones in human plasma.

Methodology – After extraction from blood, the analytes were subjected to HPLC with an XTerra® MS C18 column and a binary mobile phase consisting of 2% formic acid in water and acetonitrile under isocratic elution conditions, with ESI‐MS detection in the negative ion mode and multiple reaction monitoring (MRM).

Results – Both calibration curves showed good linearity within the concentration range 1–500 ng/mL. Limits of detection (S/N = 3) were 0.1 ng for pure substances and the limits of quantitation (S/N = 5) were 1.0 ng/mL from analyte‐spiked serum. The grand mean recovery was 90% from several subsamples of each biflavone. The imprecision (RSD) of peak areas was between 5% (intraday) and 10% (interday) for high concentrations (250 ng/mL) and between 10% (intraday) and 15% (interday) for low concentrations (1 ng/mL). Inaccuracy of the mean was less than 20% at the lower limit of quantitation.

Conclusion – The developed and validated method for determination of biflavones from human plasma was effectively applied to pharmacokinetic studies of 13 probands and preliminary results indicate biphasic concentration–time curves. Copyright © 2010 John Wiley & Sons, Ltd.
Determination of Co(II) in plant tissue by microwave digestion and ion chromatography coupled with luminol/perborate or luminol/percarbonate chemiluminescence detection
Authors: Murillo Pulgarín José A. , García Bermejo Luisa F. , Durán Armando Carrasquero
Published: September 2010

Introduction – The cobalt is an essential element for leguminous plants but may be harmful for other species; for that reason determination of Co(II) is very important for the management of polluted areas and for discover plants with capacity for the hyperaccumulation of heavy metals, which has produced a growing necessity of fast, sensitive and selective analytical techniques.

Objective – To develop an analytical procedure for the determination of cobalt in plant tissue by coupling the ionic chromatography to the luminol‐based chemiluminescence detection.

Methodology – The sample was digested in a mixture of concentrated nitric acid and hydrogen peroxide, using an microwave oven to dissolve the Co(II). The solution containing Co(II) ions was injected to an ionic chromatograph using oxalic acid as the eluent. The detection was based on the catalytic effect of Co(II) on the luminol chemiluminescence using perborate or percarbonate as oxidants. Experimental variables, such as concentrations, pH, flow rates and acid digestion conditions were optimised.

Results – Well‐resolved chromatographic peaks were obtained. The height and area showed linear dependences with the Co(II) concentration, which were used to quantify the heavy metal, with recoveries up to 95%. The microwave irradiation (60 s) was sufficient for the complete mineralisation of 200 mg of sample, employing 2 mL of the acid mixture. The method was free from the interferences, requiring less than 12 minutes to complete the analysis.

Conclusion – The method was simple and rapid for the determination of cobalt in plant tissue with detection limits comparable to those obtained with more sophisticated and expensive analytical equipments. Copyright © 2010 John Wiley & Sons, Ltd.
First‐trimester serum PAPP‐A and fβ‐hCG concentrations and other maternal characteristics to establish logistic regression‐based predictive rules for adverse pregnancy outcome
Authors: van Ravenswaaij R. , Tesselaar‐van der Goot M. , de Wolf S. , van Leeuwen‐Spruijt M. , Visser G. H. A. , Schielen P. C. J. I.
Published: September 2010

Objective

To determine the clinical relevance of maternal characteristics and first‐trimester serum concentrations of pregnancy‐associated plasma protein A (PAPP‐A) and free beta human chorionic gonadotrophin (fβ‐hCG) in predicting placenta‐related complications, miscarriage and preterm delivery.

Design, Setting and Population

A historical cohort study of data of the National Institute for Public Health and the Environment of first‐trimester screening tests performed between July 2002 and May 2006 was done. Data from 28 566 (64.1%) tests were eligible for analysis.

Methods

By logistic regression, predictive rules were made based on PAPP‐A and fβ‐hCG concentrations, maternal smoking, maternal weight and age, low birth weight, stillbirth and hypertensive disorders, miscarriage and preterm birth. Predictive values were analysed with the area under the curve (AUC) of receiver operating curves (ROC).

Results

Predictive for placenta‐related complications were low PAPP‐A, low fβ‐hCG, smoking and weight (AUC 54%). For miscarriage low PAPP‐A, low fβ‐hCG and maternal age (MA) were predictive (AUC 78%) and for preterm delivery low PAPP‐A, smoking, MA and maternal weight (AUC 55%).

Conclusion

Only the predictive model for miscarriage had a clinically relevant predictive value of 28%. Results together do not justify closer surveillance of chromosomally normal pregnancies with PAPP‐A or fβ‐hCG levels below the fifth percentile. Copyright © 2010 John Wiley & Sons, Ltd.
Elucidation of the avian nucleolar proteome by quantitative proteomics using SILAC and changes in cells infected with the coronavirus infectious bronchitis virus
Authors: Emmott Edward , Smith Catriona , Emmett Stevan R. , Dove Brian K. , Hiscox Julian A.
Published: September 2010

The nucleolus is a dynamic subnuclear compartment involved in ribosome subunit biogenesis, regulation of cell stress and modulation of cellular growth and the cell cycle, among other functions. The nucleolus is composed of complex protein/protein and protein/RNA interactions. It is a target of virus infection with many viral proteins being shown to localize to the nucleolus during infection. Perturbations to the structure of the nucleolus and its proteome have been predicted to play a role in both cellular and infectious disease. Stable isotope labeling with amino acids in cell culture coupled to LC‐MS/MS with bioinformatic analysis using Ingenuity Pathway Analysis was used to investigate whether the nucleolar proteome altered in virus‐infected cells. In this study, the avian nucleolar proteome was defined in the absence and presence of virus, in this case the positive strand RNA virus, avian coronavirus infectious bronchitis virus. Data sets, potential protein changes and the functional consequences of virus infection were validated using independent assays. These demonstrated that specific rather than generic changes occurred in the nucleolar proteome in infectious bronchitis virus‐infected cells.
The 2009 Human Liver Proteome Project (HLPP) Workshop 26 September 2009, Toronto, Canada
Authors: Gao Xue , Zheng Junjie , Beretta Laura , Mato Jose , He Fuchu
Published: September 2010

The Human Liver Proteome Project (HLPP) was formally launched by HUPO in 2002. The 11th HLPP Workshop was held on September 26th, 2009 during the 8th HUPO World Congress in Toronto, Canada. The representative progresses were presented from four groups. Subsequently, the workshop ended with a lively discussion on four topics related to the project as well as other initiatives.
Alcohol oxidation catalysed by Ru(VI) in the presence of alkaline hexacyanoferrate(III)
Authors: Poblete Francisco J. , Corrochano Pablo
Published: September 2010

The oxidation of sodium lactate, 2‐methyl‐2,4‐pentanediol, 2,4‐butanediol, 2‐butanol and 2‐propanol upon treatment with alkaline hexacyanoferrate(III) using a Ru(VI) catalyst is highly effective for the oxidation of alcohols by ${\rm Fe}({\rm CN})_{6}^{3{-} }$. The reaction mechanism proposed involves the oxidation of the alcohol by the catalyst, a process that occurs through the formation of a substrate‐catalyst complex. The decomposition of this complex yields Ru(IV) and a carbocation (owing to a hydride transfer from the α‐CH bond of the alcohol to the oxoligand of ruthenium). The role of the co‐oxidant, hexacyanoferrate(III), is to regenerate the catalyst. In the oxidation reactions, the rate constants for complex decomposition and catalyst regeneration have been determined and a comparative study of the structure versus reactivity has been carried out. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of cationic diacetylene‐co‐carbazole‐co‐fluorene polymers and their sensitive fluorescent quenching properties with DNA
Authors: Zeng Wennan , Liu Shouping , Zou Hanxun , Wang Linyun , Beuerman Roger , Cao Derong
Published: September 2010

Two neutral precursor conjugated copolymers based 2,7‐diethynylfluorene and 3,6‐diethynylcarbazole units in the main chain (PFC and PF2C) were prepared by Hay coupling polymerization. Their cationic copolymers (CPFC and CPF2C) were prepared by the methylation of their diethylpropylamino groups with CH3I. For comparison, neutral conjugated homopolymers of 2,7‐diethynylfluorene (PF), 3,6‐diethynylcarbazole units (PC) and their cationic polymers (CPF and CPC) were also prepared with the same method. A comparative study on the optical properties of cationic polymers CPFC and CPF2C in DMF and DMF/H2O showed that they underwent water‐induced aggregation. The spectral behaviors of CPFC and CPF2C with calf thymus DNA showed that a distinct fluorescent quenching took place with minute addition of CT DNA (3.3 × 10−13 M). The results showed that the polymers would be promising biosensor materials for sensitive detection of DNA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4168–4177, 2010
Molecular weight and configurational stability of poly[(fluorophenyl)acetylene]s prepared with metathesis and insertion catalysts
Authors: Bondarev Dmitrij , Zedník Jiří , Plutnarová Iva , Vohlídal Jiří , Sedláček Jan
Published: September 2010

Series of high‐cis and cis/trans poly[(fluorophenyl)acetylene]s (PFPhA) have been prepared by polymerization of (2‐fluorophenyl)acetylene, (3‐fluorophenyl)acetylene, and (4‐fluorophenyl)acetylene with catalysts: [Rh(1,5‐cyclooctadiene) OCH3]2 (high‐cis PFPhAs) and tungsten(VI) oxychloride/tetraphenyltin (cis/trans PFPhAs). The molecular weight and configurational stability under various conditions at room temperature were studied for both PFPhAs series by means of size exclusion chromatography, 1H‐NMR, and UV‐vis techniques. All samples exhibited slow degradation when exposed to the atmosphere in the solid state; the rate of degradation was independent on the F‐position on the Ph ring. The rate of degradation increased up to three orders of magnitude in the tetrahydrofuran solution where it was higher for high‐cis polymers compared with their cis/trans counterparts. The degradation of high‐cis PFPhAs was accompanied by significant cis‐to‐trans isomerization in aerated tetrahydrofuran solution. Rate of degradation and isomerization exhibited the same dependence on the F‐position on the Ph ring. The hypothesis was postulated that the degradation of high‐cis PFPhAs in solution was accelerated by cis‐to‐trans isomerization due to which the content of unpaired electrons on the main chains is enhanced. In both high‐cis and cis/trans series of polymers the ortho‐substituted isomers exhibited an enhanced stability compared with meta‐ and para‐substituted isomers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4296–4309, 2010
Hybrid organo‐inorganic globular nanospecies: Transition from macromolecule to particle
Authors: Voronina N. V. , Meshkov I. B. , Myakushev V. D. , Laptinskaya T. V. , Papkov V. S. , Buzin M. I. , Il'ina M. N. , Ozerin A. N. , Muzafarov A. M.
Published: September 2010

Molecular forms of silica based on polyethoxysiloxane, silicasol, and tetraethoxysilane, being prospective fillers for polymer nanocomposites were prepared and studied thoroughly by gel permeation chromatography (GPC), viscometry, dynamic light scattering (DLS), thermomechanics, and wide angle X‐ray scattering (WAXS). All synthesized objects were shown to possess the structure of “core ‐ shell” type. Particle radius varies in a range of 0.5–10 nm. The core structure depends on a method of preparation, while a particle morphology (share of core and shell) may be regulated within every of three methods. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4310–4322, 2010
Synthesis and characterization of novel methacrylate copolymers based on sulfonamide and coumarine: Monomer reactivity ratios, biological activity, thermal stability, and optical properties
Authors: Erol Ibrahim , Sanli Gülay , Dİlek Meltem , Ozcan Levent
Published: September 2010

The free radical copolymerization of 2‐oxo‐2‐[(4‐sulfamoylphenyl)amino]ethyl‐2‐methylpropenoate (SAEMA) with 4‐methyl‐2‐oxo‐2H‐chromen‐7‐yl‐2‐methylpropenoate (MCMA) has been carried out in 1, 4‐dioxane at 65 °C ± 1 °C and the copolymers were analyzed by Fourier‐transform infrared, 1H‐NMR, 13C‐NMR and gel permeation chromatography. 1H‐NMR and elemental analysis was used to determine the molar fractions of SAEMA and MCMA in the copolymers. The monomer‐reactivity ratios were calculated according to the general copolymerization equation using Kelen‐Tüdõs and Fineman‐Ross linearization methods. The reactivity ratios indicated a tendency toward random copolymerization. The polydispersity indices of the polymers, determined with gel permeation chromatography, suggested a strong tendency for chain termination by disproportionation. The thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. The glass‐transition temperature of the copolymers increased with increasing MCMA content in the copolymers. Also, the apparent thermal decomposition activation energies were calculated by the Ozawa method with a Shimadzu TGA 60 thermogravimetric analysis thermobalance. All the products showed moderate activity against different strains of bacteria and fungi. The photochemical properties of the polymers were investigated by UV spectra. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4323–4334, 2010
Hydrophilic functionalization of syndiotactic polystyrene via a combination of electrophilic bromination and Suzuki–Miyaura reaction
Authors: Shin Jihoon , Chang Ying , Nguyen Thi Le Thanh , Noh Seok Kyun , Bae Chulsung
Published: September 2010

Postfunctionalization of high‐molecular‐weight syndiotactic polystyrene (sPS) was achieved via combination of electrophilic bromination at the para‐position of the polymer aromatic ring and subsequent Suzuki–Miyaura cross‐coupling reactions with functionalized phenylboronic acids. The concentration of brominated styrene repeating unit in sPS was conveniently controlled by changing the ratio of added bromine relative to the polymer repeating unit. Brominated sPS (8.5 mol %) was converted quantitatively to other polar functional groups via Suzuki–Miyaura cross‐coupling reactions with various functional group‐substituted phenylboronic acids. The surface properties of functionalized sPS were studied by measuring water contact angles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4335–4343, 2010
Novel triarylamine‐based alternating conjugated polymer with high hole mobility: Synthesis, electro‐optical, and electronic properties
Authors: Chen Wen‐Hsiang , Wang Kun‐Li , Hung Wen‐Yi , Jiang Jyh‐Chiang , Liaw Der‐Jang , Lee Kueir‐Rarn , Lai Juin‐Yih , Chen Ci‐Liang
Published: September 2010

Novel bi‐triphenylamine‐containing aromatic dibromide M3, N,N‐bis(4‐bromophenyl)‐N′,N′‐dipheny‐l,4‐phenylenediamine, was successfully synthesized. The novel conjugated polymer P1 having number‐average molecular weight of 1.31 × 104 was prepared via Suzuki coupling from the dibromide M3 and 9,9‐dioctylfluorene‐2,7‐diboronic acid bis(1,3‐propanediol) ester. Polymer P1 had excellent thermal stability associated with a high glass‐transition temperature (Tg = 141 °C). The hole‐transporting and UV‐vis‐near‐infrared electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the conjugated polymer films cast onto indium‐tin oxide‐coated glass substrates exhibited two reversible oxidation redox couples at E1/2 values of 0.73 and 1.13 V versus Ag/Ag+ in acetonitrile solution. The hole mobility of the conjugated polymer P1 revealed ∼10−3 cm2 V−1 s−1, which is much higher than that of other conjugated polymer systems. The observed UV‐vis‐near‐infrared absorption change in the conjugated polymer film P1 at applied potentials ranging from 0.00 to 1.23 V are fully reversible and associated with strong color changes from pale yellowish in its neutral form to green and blue in its oxidized form. Using a combination of experimental study and theoretical investigation, we proposed an oxidation mechanism based on molecular orbital theory, which explains the cyclic voltammetry experimental results well. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Photoinitiated alternating copolymerization of dialkyl maleates and fumarates with vinyl ethers
Authors: Crivello James V. , McGrath Thomas M.
Published: September 2010

A systematic study of the free radical photoinitiated alternating crosslinking copolymerizations of dialkyl maleates and furmarates with multifunctional vinyl ethers was carried out. The photocopolymerizations were fast and highly efficient when carried out using a variety of α‐cleavage photoinitiators. The effects of the structures of the both the unsaturated esters and the vinyl ether monomers were examined. Dialkyl maleates were observed to be more reactive than the corresponding fumarate esters. The photopolymerization rates of several of these comonomer pairs were compared with standard diacrylate and dimethacrylate monomers. A range of different physical properties can be obtained by varying the length of the alkyl chain on alcohol portion of the unsaturated ester monomer. Prospects for the use of these comonomer systems in UV curable coatings, adhesives, printing inks, and composites are discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Preparation of highcis‐1,4 polyisoprene with narrow molecular weight distribution via coordinative chain transfer polymerization
Authors: Fan Changliang , Bai Chenxi , Cai Hongguang , Dai Quanquan , Zhang Xuequan , Wang Fosong
Published: September 2010

Highcis‐1,4 polyisoprene with narrow molecular weight distribution has been prepared via coordinative chain transfer polymerization (CCTP) using a homogeneous rare earth catalyst composed of neodymium versatate (Nd(vers)3), dimethyldichlorosilane (Me2SiCl2), and diisobutylaluminum hydride (Al(i‐Bu)2H) which has strong chain transfer affinity is used as both cocatalyst and chain transfer agent (CTA). Differentiating from the typical chain shuttling polymerization where dual‐catalysts/CSA system has been used, one catalyst/CTA system is used in this work, and the growing chain swapping between the identical active sites leads to the formation of highcis‐1,4 polyisoprene with narrowly distributed molecular weight. Sequential polymerization proves that irreversible chain termination reactions are negligible. Much smaller molecular weight of polymer obtained than that of stoichiometrically calculated illuminates that, differentiating from the typical living polymerization, several polymer chains can be produced by one neodymium atom. The effectiveness of Al(i‐Bu)2H as a CTA is further testified by much broad molecular weight distribution of polymer when triisobutylaluminum (Al(i‐Bu)3), a much weaker chain transfer agent, is used as cocatalyst instead of Al(i‐Bu)2H. Finally, CCTP polymerization mechanism is validated by continuously decreasedMw/Mnvalue of polymer when increasing concentration of Al(i‐Bu)2H extra added in the Nd(ver)3/Me2SiCl2/Al(i‐Bu)3catalyst system. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Proton‐conductive polymer nanocomposite membranes prepared from telechelic fluorinated polymers containing perfluorosulfonic acid side chains
Authors: Chanthad Chalathorn , Xu Kui , Huang He , Wang Qing
Published: September 2010

New classes of fluorinated polymer–polysilsesquioxane nanocomposites have been designed and synthesized. The synthesis method includes radical polymerization using the functional benzoyl peroxide initiator for the telechelic fluorinated polymers with perfluorosulfonic acids in the side chains and a subsequent in situ sol–gel condensation of the prepared triethoxylsilane‐terminated fluorinated polymers with oxide precursors. The telechelic polymer and nanocomposites have been carefully characterized by 1H and 19F NMR, FTIR, TGA, and TEM. The ion‐exchange capacity (IEC), water uptake, the state of the absorbed water, and transport properties of the composite membranes have been extensively studied as a function of the content and structure of the fillers. Unlike the conventional Nafion/silica composites, the proton conductivity of the prepared membranes increases steadily with the addition of small amounts of the polysilsesquioxane fillers. In particular, the sulfopropylated polysilsesquioxane‐based nanocomposites display proton conductivities greater than Nafion. This is attributed to the presence of pendant sulfonic acids in the fillers, which increases IEC and offers continuous proton transport channels between the fillers and the polymer matrix. The methanol permeability of the prepared membranes has also been examined. Lower methanol permeability and higher electrochemical selectivity than those of Nafion have been demonstrated in the polysilsesquioxane‐based nanocomposites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Energy diagrams and stability restrictions for electroelastic generators
Authors: Díaz‐Calleja Ricardo , Llovera‐Segovia Pedro
Published: September 2010

The relation between electric and mechanical properties of dielectric elastomers allows using them as energy convertors under some conditions. The process is based on the relations between mechanical and electrical energy stored on the material. In this work, cycles of maximal mechanical energy to be converted into electrical energy are presented. The purpose of this article is to give a general formulation of electroelastic generator relations considering (1) Mooney‐Rivlin materials, (2) floating sample between electrodes and sample with compliant electrodes, and (3) explicit thermodynamic stability criteria. Estimations on the maximal energy to be converted are made. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2023–2028, 2010
Conductive and optical properties of PPV modified by N+ ion implantation
Authors: Li Baoming , Cheng Lei , Zheng Yuying
Published: September 2010

In this article, a soluble poly[2‐methoxy‐5‐(3′‐methyl)butoxy]‐p‐phenylene vinylene (MMB‐PPV) was synthesized by dehydrochlorination reaction and the MMB‐PPV film was implanted by nitrogen ions (N+) with the ion dose and energy in the range of 3.8 × 1015 to 9.6 × 1016 ions/cm2 and 15–35 keV, respectively. The surface conductivity, optical absorption, optical band gap (Eg) of modified MMB‐PPV film were studied, and the third‐order nonlinear optical susceptibility (χ(3)) as well as its environmental stability of modified MMB‐PPV film were also measured by degenerate four‐wave mixing system. The results showed that the surface conductivity of MMB‐PPV film was up to 3.2 × 10−2 S when ion implantation was performed with the energy of 35 keV at an ion dose of 9.6 × 1016 ions/cm2, which was seven order of magnitude higher than that of the pristine film. UV‐Vis absorption spectra demonstrated that the optical absorption of MMB‐PPV film was enhanced gradually in the visible region followed by a red shift of optical absorption threshold and the Eg value was reduced from 2.12 eV to 1.59 eV with the increase of ion dose and energy. The maximum χ(3) value of 2.45 × 10−8 esu for modified MMB‐PPV film was obtained with the ion energy of 20 keV at an ion dose of 3.8 × 1016 ions/cm2, which was almost 33 times larger than that for pristine film. In comparison to the reduction of 17% in the χ(3) value of pristine MMB‐PPV film, the maximum χ(3) value of 2.45 × 10−8 esu for modified MMB‐PPV film decreased by over 5.3% when they had been exposed under the same ambient conditions for 90 days. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2072–2077, 2010
Molecular dynamics simulations of semicrystalline polymers: Crystallization, melting, and reorganization
Authors: Sommer Jens‐Uwe , Luo Chuanfu
Published: September 2010

Large‐scale molecular dynamics (MD) simulations of semicrystalline entangled polymers are carried out to explore crystallization and melting processes. Semicrystalline polymers are obtained from disordered melts via homogeneous nucleation. In the early stage of the crystallization process, the collective scattering does not show the emergence of nuclei seeds. Although the crystallization process is thermodynamically simple, the melting process is complex resulting in multiple‐peaked melting endotherms. The molecular origin is found to be the different thermal stabilities of microcrystalline domains (MCDs). Coexistence of melting and growth of different MCDs during sufficiently slow heating enlarges the difference of their thermal stabilities. An increase of stem length close to the melting point is assisted by disorder effects in particular in the surface regions of the MCDs. The number of trans–trans states is decreasing, which increases the flexibility and mobility of the crystalline stems. We have also investigated self‐seeding processes, and we show how these can be used to obtain single lamellar crystals in MD simulations. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
The activity of recombinant human neuroglobin as an antioxidant and free radical scavenger
Authors: Li Weiguang , Wu Yonghong , Ren Changhong , Lu Yiming , Gao Yan , Zheng Xiaofei , Zhang Chenggang
Published: September 2010

Free radicals are by‐products of metabolism and exist in a homeostasis between generation and scavenging in vivo. Excessive free radicals cause various diseases, including nervous system diseases. Neuroglobin (Ngb), a nervous system‐specific oxygen‐binding protein, has been suggested to be a potential free radical scavenger in the nervous system in vivo; however, its underlying mechanism remains unclear. In this study, we investigated the antioxidant potential and free radical scavenging properties of recombinant human Ngb (rhNgb) in vitro. Interestingly, we found that the rhNgb protein itself has a direct and distinct antioxidant capacity and can efficiently scavenge a variety of free radicals, including the [2,2′‐azino‐di‐(3‐ethyl‐benzthiazoline‐6‐sulfonic acid)] (ABTS) cation, superoxide anion, hydrogen peroxide, and hydroxyl radical. The capacity of rhNgb to scavenge the superoxide anion and hydrogen peroxide was even comparable to that of vitamin C. In addition, rhNgb had Fe2+ chelating activity but hemoglobin did not. In conclusion, our results indicated that the rhNgb protein itself has antioxidant and free radical scavenging activities, providing fundamental evidence for the neuroprotective function of Ngb. These data provide key information for the origin of the neuroprotective and physiological role of Ngb and will promote the treatment of reactive oxygen species (ROS)‐related diseases using this novel oxygen‐binding globin. Proteins 2010. © 2010 Wiley‐Liss, Inc.
An X‐ray diffraction technique for analyzing basal‐plane stacking faults in GaN
Authors: Paduano Qing S. , Weyburne David W. , Drehman Alvin J.
Published: September 2010

An X‐ray diffraction (XRD) technique for analyzing basal‐plane stacking faults (BSFs) is introduced and tested on GaN. The analysis considers the coexistence of multiple X‐ray broadening terms including tilt, twist, limited coherence length, and inhomogeneous strain. By measuring and fitting a series of symmetric and asymmetric reflections planes, we deduce the lattice tilt, twist, lateral coherence length, and inhomogeneous strain contributions, which allow us to determine the existence of any additional broadening in m‐plane GaN. We found that in fact certain ω‐scans do have excess broadening and that their lattice plane dependence is similar to the functional dependence of BSFs derived for powder XRD (θ/2θ‐scan). Applying such functional dependence allows us to estimate the BSF densities (I1‐ and I2‐type). The typical stacking fault density was estimated to be 1 × 106/cm in m‐plane GaN grown on m‐plane sapphire by MOCVD, while the relative densities of I1‐ and I2‐type are sample dependent. In contrast to the m‐plane GaN, stacking faults in GaN on c‐plane sapphire do not contribute significantly to Bragg peak broadening and are below the detection limit.
Correlation of geometrical and electronic properties in metallic nanowires
Authors: Pfnür H. , Tegenkamp C. , Czubanowski M. , Lükermann D. , Rönspies J. , Wießell S.
Published: September 2010

The structure on the atomic scale was found to be directly correlated with the electronic and transport properties of ultra‐thin metallic wires. We present examples of both self‐organized and artificially structured nanowires in the system Pb/Si(557). We demonstrate that artificial structuring on the nanoscale allows identification and determination of the electrical transport properties of atomic size defects, using Si(557) as a quasi‐insulating substrate and a Si double step in a monolayer high Pb nanowire as an example. One‐dimensional (1D) properties with strong electron correlation and various instabilities in metallic chains or ribbons generated by metal adsorption of sub‐monolayers on insulating substrates like Si(111) or Si(557) turn out to always be modified by the unavoidable coupling to 2D and 3D. The wealth of new and partly unexpected phenomena is exemplified here again in monolayers of Pb on Si(557), which forms wire‐like arrays. We identify structural self‐stabilization as the origin of 1D electronic transport and show that a new 1D state is generated by step decoration. Magnetoconductance measurements yield even deeper insight into mechanisms of electronic transport, as also exemplified in this specific system.
Organic solar cells with very high fill factor and voltage using tetrapropyl‐tetraphenyl‐diindenoperylene as green donor
Authors: Meiss Jan , Hummert Markus , Ziehlke Hannah , Leo Karl , Riede Moritz
Published: September 2010

We present 2,3,10,11‐tetrapropyl‐1,4,9,12‐tetraphenyl‐diindeno[1,2,3‐cd:1′,2′,3′‐lm]perylene (P4‐Ph4‐DIP) as new green donor for small molecule organic solar cells (SMOSC). P4‐Ph4‐DIP absorbs in the green spectral range of 490–580 nm and thus is a decisive building block towards broad coverage of the sun spectrum. SMOSC with P4‐Ph4‐DIP as donor and C60 as blue‐absorbing acceptor display very high fill factors FF > 76% and open circuit voltages of 0.99 V, reaching η = 1.92% for 12 nm P4‐Ph4‐DIP. Current voltage and external quantum efficiency spectra suggest that an exciton diffusion length ED < 20 nm is the main limiting factor. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of open‐ended TiO2 nanotube arrays by a simple two‐step anodization
Authors: Zhang Zhi‐Kun , Guo Deng‐Zhu , Xing Ying‐Jie , Zhang Geng‐Min
Published: September 2010

We report a two‐step anodizing approach for the fabrication of large‐scale open‐ended TiO2 nanotube arrays (TNAs) on a conductive Au layer. In this method, a deposited Ti/Au bilayer film is initially anodized under a high potential to form and shape the TNAs. A following low potential is then in situ applied at a suitable time to slowly eliminate the remaining barrier layer at the bottom of the TNAs without further treatment. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ethical considerations in industry‐sponsored Multiregional clinical trials
Authors: Ibia Ekopimo , Binkowitz Bruce , Saillot Jean‐Louis , Talerico Steven , Koerner Chin , Ferreira Irene , Agarwal Anupam , Metz Craig , Maman Marianne
Published: September 2010

During the last several decades, the scientific and ethics communities have addressed important ethical issues in medical research, resulting in the elaboration and adoption of concepts, guidelines, and codes.

Ethical issues in the conduct of Multiregional Clinical Trials have attracted significant attention mainly in the last two decades. With the globalization of clinical research and the rapid expansion to countries with a limited tradition of biomedical research, sponsors must proactively address local ethical issues, the adequacy of oversight as well as the applicability and validity of data, and scientific conclusions drawn from diverse patient populations.

This paper highlights some core ethical principles and milestones in medical research, and, from an industry perspective, it discusses ethical issues that the clinical trial team may face when conducting Multiregional Clinical Trials (MRCT, clinical trials conducted at sites located across multiple geographic regions of the world). This paper further highlights the areas of consensus and controversies and proposes points to consider. Copyright © 2010 John Wiley & Sons, Ltd.
A high‐performance, safer and semi‐automated approach for the δ18O analysis of diatom silica and new methods for removing exchangeable oxygen
Authors: Chapligin B. , Meyer H. , Friedrichsen H. , Marent A. , Sohns E. , Hubberten H.‐W.
Published: September 2010

The determination of the oxygen isotope composition of diatom silica in sediment cores is important for paleoclimate reconstruction, especially in non‐carbonate sediments, where no other bioindicators such as ostracods and foraminifera are available. Since most currently available analytical techniques are time‐consuming and labour‐intensive, we have developed a new, safer, faster and semi‐automated online approach for measuring oxygen isotopes in biogenic silica. Improvements include software that controls the measurement procedures and a video camera that remotely records the reaction of the samples under BrF5 with a CO2 laser. Maximum safety is guaranteed as the laser‐fluorination unit is arranged under a fume hood in a separate room from the operator. A new routine has been developed for removing the exchangeable hydrous components within biogenic silica using ramp degassing. The sample plate is heated up to 1100°C and cooled down to 400°C in ∼7 h under a flow of He gas (the inert Gas Flow Dehydration method – iGFD) before isotope analysis. Two quartz and two biogenic silica samples (∼1.5 mg) of known isotope composition were tested. The isotopic compositions were reproducible within an acceptable error; quartz samples gave a mean standard deviation of <0.15‰ (1σ) and for biogenic silica <0.25‰ (1σ) for samples down to ∼0.3 mg. The semi‐automated fluorination line is the fastest method available at present and enables a throughput of 74 samples/week. Copyright © 2010 John Wiley & Sons, Ltd.
A robotic system for monitoring carp in Minnesota lakes
Authors: Tokekar Pratap , Bhadauria Deepak , Studenski Andrew , Isler Volkan
Published: September 2010

Robotic sensor networks (RSNs) find increasing use in environmental monitoring as they can collect data from obscure, hard‐to‐reach places over long periods of time. This work reports progress in building a network of small, lightweight robotic rafts that will be used to monitor common carp tagged with radio transmitters across Minnesota lakes. We describe the design and architecture of the robotic raft and demonstrate the robustness of our waypoint navigation algorithm through field tests conducted in various lakes. We also present results from experiments aimed at localizing tagged fish. © 2010 Wiley Periodicals, Inc.
Model selection procedure for high‐dimensional data
Authors: Zhang Yongli , Shen Xiaotong
Published: September 2010

For high‐dimensional regression, the number of predictors may greatly exceed the sample size but only a small fraction of them are related to the response. Therefore, variable selection is inevitable, where consistent model selection is the primary concern. However, conventional consistent model selection criteria like Bayesian information criterion (BIC) may be inadequate due to their nonadaptivity to the model space and infeasibility of exhaustive search. To address these two issues, we establish a probability lower bound of selecting the smallest true model by an information criterion, based on which we propose a model selection criterion, what we call RICc, which adapts to the model space. Furthermore, we develop a computationally feasible method combining the computational power of least angle regression (LAR) with that of RICc. Both theoretical and simulation studies show that this method identifies the smallest true model with probability converging to one if the smallest true model is selected by LAR. The proposed method is applied to real data from the power market and outperforms the backward variable selection in terms of price forecasting accuracy. Copyright © 2010 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 3: 350‐358, 2010
A novel framework for detecting maximally banded matrices in binary data
Authors: Alqadah Faris , Bhatnagar Raj , Jegga Anil
Published: September 2010

Binary data occurs often in real‐world applications ranging from social networks to bioinformatics. As such, extracting patterns from binary data has been a fundamental task of data mining. Recently, the utility of banded structures in binary matrices has been pointed out for applications such as paleontology, bioinformatics, and social networking. A binary matrix has a banded structure if both the rows and columns can be permuted so that the 1s exhibit a staircase pattern down the rows, along the leading diagonal. Natural interpretations of banded structures include overlapping communities in social networks, patterns of species occurring in spatially correlated sites, and overlapping roles of genes in various diseases. In this paper, we show the correspondence between formal concept analysis and banded structure; as a direct result of this correspondence a novel framework for discovering banded structures is presented. Utilizing the framework, the MMBS algorithm (mine maximally banded submatrices) is developed. The current state‐of‐the‐art algorithm, MBS, only allows for the discovery of a single band and assumes a fixed‐column permutation. On the other hand, MMBS facilitates the discovery of multiple bands that may possibly be overlapping or segmented. Our experimental results, presented here, clearly indicate the advantage of MMBS over MBS with both, synthetic and real datasets. Copyright © 2010 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 3: 431‐445, 2010
Secrecy coding for the binary symmetric wiretap channel
Authors: Chen Yanling , Han Vinck A. J.
Published: September 2010

In this paper, we investigate the binary symmetric wiretap channel. We show that the secrecy capacitycan be achieved by using random linear codes. The random coding scheme gives insight into the structure of secrecy capacity achieving code but unfortunately involves a rather impractical decoder. We further explore the coset‐coding schemeconstructed by linear codes. As a result, we give an upper bound on the total information loss, which sheds light on the design of the applicable coset codes for the secure transmission with limited information leakage. Copyright © 2010 John Wiley & Sons, Ltd.
Several methods to assess improvement in risk prediction models: Extension to survival analysis
Authors: Chambless Lloyd E. , Cummiskey Christopher P. , Cui Gang
Published: September 2010

Risk prediction models have been widely applied for the prediction of long‐term incidence of disease. Several parameters have been identified and estimators developed to quantify the predictive ability of models and to compare new models with traditional models. These estimators have not generally accounted for censoring in the survival data normally available for fitting the models. This paper remedies that problem. The primary parameters considered are net reclassification improvement (NRI) and integrated discrimination improvement (IDI). We have previously similarly considered a primary measure of concordance, area under the ROC curve (AUC), also called the c‐statistic. We also include here consideration of population attributable risk (PAR) and ratio of predicted risk in the top quintile of risk to that in the bottom quintile. We evaluated estimators of these various parameters both with simulation studies and also as applied to a prospective study of coronary heart disease (CHD). Our simulation studies showed that in general our estimators had little bias, and less bias and smaller variances than the traditional estimators. We have applied our methods to assessing improvement in risk prediction for each traditional CHD risk factor compared to a model without that factor. These traditional risk factors are considered valuable, yet when adding any of them to a risk prediction model that has omitted the one factor, the improvement is generally small for any of the parameters. This experience should prepare us to not expect large values of the risk prediction improvement evaluation parameters for any new risk factor to be discovered. Copyright © 2010 John Wiley & Sons, Ltd.
Understanding the Photothermal Conversion Efficiency of Gold Nanocrystals
Authors: Chen Huanjun , Shao Lei , Ming Tian , Sun Zhenhua , Zhao Chunmei , Yang Baocheng , Wang Jianfang
Published: September 2010

Plasmon‐based photothermal therapy is one of the most intriguing applications of noble metal nanostructures. The photothermal conversion efficiency is an essential parameter in practically realizing this application. The effects of the plasmon resonance wavelength, particle volume, shell coating, and assembly on the photothermal conversion efficiencies of Au nanocrystals are systematically studied by directly measuring the temperature of Au nanocrystal solutions with a thermocouple and analyzed on the basis of energy balance. The temperature of Au nanocrystal solutions reaches the maximum at ∼75°C when the plasmon resonance wavelength of Au nanocrystals is equal to the illumination laser wavelength. For Au nanocrystals with similar shapes, the larger the nanocrystal, the smaller the photothermal conversion efficiency becomes. The photothermal conversion can also be controlled by shell coating and assembly through the change in the plasmon resonance energy of Au nanocrystals. Moreover, coating Au nanocrystals with semiconductor materials that have band gap energies smaller than the illumination laser energy can improve the photothermal conversion efficiency owing to the presence of an additional light absorption channel.
Interaction of Hypoxia-Inducible Factor-1α and Notch Signaling Regulates Medulloblastoma Precursor Proliferation and Fate
Authors: Pistollato Francesca , Rampazzo Elena , Persano Luca , Abbadi Sara , Frasson Chiara , Denaro Luca , D'Avella Domenico , Panchision David M. , Puppa Alessandro Della , Scienza Renato , Basso Giuseppe
Published: September 2010

Medulloblastoma (MDB) is the most common brain malignancy of childhood. It is currently thought that MDB arises from aberrantly functioning stem cells in the cerebellum that fail to maintain proper control of self-renewal. Additionally, it has been reported that MDB cells display higher endogenous Notch signaling activation, known to promote the survival and proliferation of neoplastic neural stem cells and to inhibit their differentiation. Although interaction between hypoxia-inducible factor-1α (HIF-1α) and Notch signaling is required to maintain normal neural precursors in an undifferentiated state, an interaction has not been identified in MDB. Here, we investigate whether hypoxia, through HIF-1α stabilization, modulates Notch1 signaling in primary MDB-derived cells. Our results indicate that MDB-derived precursor cells require hypoxic conditions for in vitro expansion, whereas acute exposure to 20% oxygen induces tumor cell differentiation and death through inhibition of Notch signaling. Importantly, stimulating Notch1 activation with its ligand Dll4 under hypoxic conditions leads to expansion of MDB-derived CD133+ and nestin+ precursors, suggesting a regulatory effect on stem cells. In contrast, MDB cells undergo neuronal differentiation when treated with γ-secretase inhibitor, which prevents Notch activation. These results suggest that hypoxia, by maintaining Notch1 in its active form, preserves MDB stem cell viability and expansion.
Development of Multiple Power Quality Supply System
Authors: Hirose Keiichi , Fukui Akiyoshi , Matsumoto Akira , Murai Hideyuki , Takeda Takashi , Matsumura Toshiro
Published: September 2010

This paper describes the characteristics and performances of a multiple power quality supply system (MPQSS), which consists of power electronics‐based voltage compensators and three types of distributed generators (DGs). Its original concept of a future power delivery system having different service levels to meet each customer or load requirement at the same time was proposed as Flexible, Reliable, and Intelligent Electrical eNergy Delivery System (FRIENDS). The effectiveness of the developed power system was measured during an actual field demonstration conducted in 2007 by the New Energy and Industrial Technology Development Organization (NEDO), Sendai, Japan. Its effectiveness in feeding four classes of alternative current (AC) and one of direct current (DC) power while meeting various customer requirements was confirmed. Some sets of test data and an analysis using the data indicate that the developed system meets all the requirements for DG‐related plants and has additional benefits. The power system maintains voltage and frequency conditions without interruption in the every state, grid interconnection, islanding, and backup modes. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.