bluuebunny/crossref_metadata_2025_split huggingface dataset:
Does nitrogen concentration affect relative uptake rates of nitrate, ammonium, and glycine?
Authors: Warren Charles R. 
Published: March 2009

AbstractPlant roots are exposed to a variety of nitrogen forms (e.g., nitrate, ammonium, amino acids) and take up these forms at different rates. Many studies have investigated whether plants prefer nitrate, ammonium, or amino acids; but studies may not be comparable because they used substrate concentrations between 100 and 2000 μmol L–1. This study tests the hypothesis that substrate concentrations from 10 to 1750 μmol L–1 affect plant preference for N forms. Nitrogen uptake by the herb Ocimum basilicum and the evergreen tree Eucalyptus regnans was examined by placing roots of intact seedlings in equimolar mixtures of nitrate, ammonium, and glycine in which one of the N forms was 15N‐labelled (and 13C‐labelled in the case of glycine). In both species, preference for N forms was affected by substrate concentration. At 10 μmol L–1 (O. basilicum) or 10 and 50 μmol L–1 (E. regnans), rates of N uptake did not differ among N forms. At substrate concentrations of 50 μmol L–1 and greater O. basilicum took up ammonium the fastest, glycine the slowest, and nitrate at an intermediate rate. At substrate concentrations from 100 to 1750 μmol L–1, E. regnans took up ammonium the fastest with glycine and nitrate taken up at slower rates. The absence of significant differences at lower concentrations was a true biological effect rather than a function of larger relative errors. This study demonstrates that substrate concentration has a large effect on plant preference for N forms, and sounds a warning for studies of N nutrition that do not consider the concentration‐dependence of plant preference for N forms.
State‐ and time‐resolved rotational relaxation signatures in two‐color resonant four‐wave mixing spectra
Authors: Chen X. , Settersten T. B. , Kouzov A. P. 
Published: March 2009

AbstractTwo‐color resonant four‐wave mixing (TC‐RFWM) is advertised as a unique spectroscopic device, enabling direct time‐resolved measurement of the collisional state‐to‐state transfer characteristics (rates and correlation times). These characteristics are phase‐sensitive and open wider opportunities to study the rotational relaxation processes. Further perspectives are offered by the recently recorded collision‐induced picosecond TC‐RFWM signals of OH. Their quantitative interpretation is now under development.Copyright © 2009 John Wiley & Sons, Ltd.
Raman scattering studies of (GaP)n/(InP)n (n = 1, 1.7, 2) short‐period superlattice structures
Authors: Rho H. , Lim J.‐R. , Song J. D. , Choi W. J. , Lee Y. T. 
Published: March 2009

AbstractWe report Raman scattering from (GaP)n/(InP)n (n = 1, 1.7, 2) short‐period superlattice (SPS) structures to study the effect of lateral composition modulation (LCM) on the behavior of optical phonons. Cross‐sectional transmission electron microscope images revealed that LCM was formed with complex pattern in the n = 1.7 and n = 2 samples grown at 490 °C. Interestingly, both the InP‐ and the GaP‐like longitudinal optical (LO) phonon energies increased systematically as the number of monolayers was increased from n = 1 to n = 2. A significant broadening of the phonon line shapes was also observed for the n = 1.7 and n = 2 samples. In contrast, for samples grown at 425 °C, both the increase of the LO phonon energies and the broadening of the phonon line shapes were observed only when n = 1.7. Our results demonstrate that the optical phonons in the (GaP)n/(InP)n SPS structures are significantly affected in the occurrence of LCM related to the growth temperature and the number of monolayers.Copyright © 2009 John Wiley & Sons, Ltd.
Detection of horse DNA in food and feedstuffs using a polymerase chain reaction assay
Authors: Martín Irene , García Teresa , Fajardo Violeta , Rojas María , Hernández Pablo E , González Isabel , Martín Rosario 
Published: March 2009

AbstractBACKGROUND: Development of accurate methods for rapid identification of animal materials in food and feedstuffs is essential to protect consumers and also to enforce feed bans. The aim of this study was to develop a polymerase chain reaction (PCR) assay for the specific detection of horse DNA in food and feedstuffs.RESULTS: The primers designed amplified a horse‐specific fragment of 114 bp of the mitochondrial 12S ribosomal RNA gene. The specificity of the primers was verified by PCR analysis of DNA from 32 non‐target species including mammals, birds, fish and plant species. The PCR assay developed allowed the detection of raw and heated horse tissues in muscle/oats mixtures even when the concentration of horse‐derived materials was reduced to 1 g kg−1.CONCLUSION: The performance of the method was not affected by prolonged heat treatment (up to 133 °C for 20 min at 300 kPa), and consequently it could be very useful in verifying the origin of raw materials in food and feedstuffs submitted to denaturing technologies, for which other methods cannot be applied. Copyright © 2009 Society of Chemical Industry
Prospects for measurement‐based quantum computing with solid state spins
Authors: Benjamin S.C. , Lovett B.W. , Smith J.M. 
Published: March 2009

AbstractThis article aims to review the developments, both theoretical and experimental, that have in the past decade laid the ground for a new approach to solid state quantum computing. Measurement‐based quantum computing (MBQC) requires neither direct interaction between qubits nor even what would be considered controlled generation of entanglement. Rather it can be achieved using entanglement that is generated probabilistically by the collapse of quantum states upon measurement. Single electronic spins in solids make suitable qubits for such an approach, offering long coherence times and well defined routes to optical measurement. We will review the theoretical basis of MBQC and experimental data for two frontrunner candidate qubits – nitrogen‐vacancy (NV) centres in diamond and semiconductor quantum dots – and discuss the prospects and challenges that lie ahead in realising MBQC in the solid state.
Self‐Assembled Nanogel of Hydrophobized Dendritic Dextrin for Protein Delivery
Authors: Ozawa Yayoi , Sawada Shin‐ichi , Morimoto Nobuyuki , Akiyoshi Kazunari 
Published: March 2009

AbstractHighly branched cyclic dextrin derivatives (CH‐CDex) that are partly substituted with cholesterol groups have been synthesized. The CH‐CDex forms monodisperse and stable nanogels with a hydrodynamic radii of ≈10 nm by the self‐assembly of 4–6 CH‐CDex macromolecules in water. The CH‐CDex nanogels spontaneously trap 10–16 molecules of fluorescein isothiocyanate‐labeled insulin (FITC‐Ins). The complex shows high colloidal stability: no dissociation of trapped insulin is observed after at least 1 month in phosphate buffer (0.1 M, pH 8.0). In the presence of bovine serum albumin (BSA, 50 mg · mL−1), which is a model blood system, the FITC‐Ins trapped in the nanogels is continuously released (≈20% at 12 h) without burst release. The high‐density nanogel structure derived from the highly branched CDex significantly affects the stability of the nanogel–protein complex.magnified image
A Micellar Complex of a Conjugated Polyelectrolyte for Efficient FRET to Dye‐Labeled DNA
Authors: Nayak Rati Ranjan , Nag Okhil Kumar , Kang Mijeong , Jin Youngeup , Suh Hongsuk , Lee Kwanghee , Woo Han Young 
Published: March 2009

AbstractA polymer–surfactant micellar complex has been studied as a fluorescence resonance energy transfer (FRET) donor to fluorescein‐labeled DNA (ssDNA‐Fl). In water, the molar absorptivity and fluorescence quantum efficiency of cationic poly(fluorene‐co‐phenylene) (c‐PFP) are substantially increased in the presence of non‐ionic surfactants. A TEM microscopic study shows the formation of a nanowire micellar complex of c‐PFP and the surfactants. About a 400% enhancement of the FRET signal is measured in c‐PFP/ssDNA‐Fl with Brij 30, relative to that without surfactants. The signal amplification is successfully modulated using different types of non‐ionic surfactants which perturb the complexation, fine‐structure of the complex (i.e., donor‐acceptor separation), and the resulting energy transfer process.magnified image
Precipitation Polymerization in Ethanol and Ethanol/Water to Prepare Uniform Microspheres of Poly(TMPTA‐styrene)
Authors: Kong Xiang Zheng , Gu Xiang Ling , Zhu Xiaoli , Zhang Lina 
Published: March 2009

AbstractThe precipitation polymerization of styrene‐trihydroxymethyl propane triacrylate has been carried out using ethanol and an ethanol/water mixture as the solvent. Uniform microspheres with high monomer conversion are achieved within 4 h, a much shorter polymerization time than that reported for the precipitation polymerization of divinyl benzene‐styrene in acetonitrile. The results clearly demonstrate that use of water as a co‐solvent is indeed very effective to promote the polymerization to high conversion and to obtain uniform microspheres. With no water under the otherwise same experimental conditions, only about 57% of monomer conversion is obtained; while the monomer conversion is remarkably increased to 96% when 12 vol.‐% of water is used.magnified image
A direct method for a regularized least‐squares problem
Authors: Elfving Tommy , Skoglund Ingegerd 
Published: March 2009

AbstractWe consider a linear system of the form A1x1+ A2x2+η=b1. The vector η consists of identically distributed random variables all with mean zero. The unknowns are split into two groups x1 and x2. In the model usually there are more unknowns than observations and the resulting linear system is most often consistent having an infinite number of solutions. Hence some constraint on the parameter vector x is needed. One possibility is to avoid rapid variation in, e.g. the parameters x2. We formulate the problem as a partially regularized least‐squares problem, and propose a direct solution method based on the QR decomposition of matrix blocks. Further we consider regularizing using one and two regularization parameters, respectively. We also discuss the choice of regularization parameters, and extend Reinsch's method to the case with two parameters. Also the cross‐validation technique is treated. We present test examples taken from an application in modelling of the substance transport in rivers. Copyright © 2009 John Wiley & Sons, Ltd.
A mixed finite element method for non‐linear and nearly incompressible elasticity based on biorthogonal systems
Authors: Lamichhane Bishnu P. 
Published: March 2009

AbstractWe present a finite element method for non‐linear and nearly incompressible elasticity. The formulation is based on Petrov–Galerkin discretization for the pressure and is closely related to the average nodal pressure formulation presented earlier in the context of incompressible and nearly incompressible dynamic explicit applications (Commun. Numer. Meth. Engng 1998; 14:437–449). Some numerical examples are presented to show the efficiency of the approach. Copyright © 2009 John Wiley & Sons, Ltd.
Preparation and properties of water‐soluble chitosan and polyvinyl alcohol blend films as potential bone tissue engineering matrix
Authors: Ma Guiping , Yang Dongzhi , Su Dandan , Mu Xueyan , Kennedy John F , Nie Jun 
Published: March 2009

AbstractThe blend film was prepared by casting solutions of water‐soluble hydroxyethyacryl‐chitosan (HEA‐CS) and polyvinyl alcohol (PVA) and cross‐linked by glutaraldehyde. The structure and properties of the blend films were estimated by wide‐angle X‐ray diffraction (WXRD), contact angle measurements with water, and scanning electron microscopy (SEM). The tensile properties of the blend films were investigated and the tensile strength (TS) and the elongation increased with the increased amount of PVA. The thermal stability (thermogravimetric (TG) and derivative thermogravimetric (DTG)) was evaluated and HEA‐CS was more thermally‐stable than that of PVA. The water swelling properties analysis indicated that HEA‐CS in the blends promoted the water absorption owing to its porous structure and the antimicrobial ability of the blend films was retained. Indirect cytotoxicity assessment of the blend films with human bone sarcoma cell (SW1353) indicated that the biomaterials were non‐toxic and did not release substances harmful to living cells. Copyright © 2009 John Wiley & Sons, Ltd.
Genomic and phenotypic analysis reveals a key role for CCN1 (CYR61) in BAG3—modulated adhesion and invasion
Authors: Kassis Jareer N , Virador Victoria M , Guancial Elizabeth A , Kimm Daniel , Ho Allen S , Mishra Mark , Chuang Eric Y , Cook John , Gius David , Kohn Elise C 
Published: March 2009

AbstractChaperone protein quantity may regulate the balance of proteins involved in invasion and malignancy. BAG3 is a co‐chaperone and pro‐survival protein that has been implicated in adhesion, migration, and metastasis. We reported that BAG3 overexpression in MDA435 human breast cancer cells results in a significant decrease in migration and adhesion to matrix molecules that is reversed upon deletion of the BAG3 proline‐rich domain (dPXXP). We now hypothesize that transcriptional analysis would identify proteins involved in matrix‐related processes that are regulated by BAG3 and/or its PXXP domain mutant. Expression array analysis of MDA435 cells overexpressing either wild‐type BAG3 (FL) or dPXXP identified CCN1 as a BAG3 target protein. CCN1 is a known AP‐1 target. Increased AP‐1 transcriptional activity and AP‐1 DNA‐binding was found in MDA435 dPXXP cells. Consistent with these findings, CCN1 quantity and secretion were increased in dPXXP mutants but suppressed in FL cells; both BAG3 forms resulted in up‐regulated CCN1 in HeLa cells. CCN1 silencing in the BAG3 FL overexpressors reduced the already low phospho‐integrin β1 in response to attachment on collagen IV. Matrigel invasion of HeLa cells engineered with the BAG3 constructs was enhanced in FL cells and minimal in dPXXP cells. CCN1 silencing blocked a greater percentage of the serum‐induced invasion in FL cells than in dPXXP cells. This implies a context‐dependent function of BAG3 on CCN1 and thus mesenchymal behaviour. CCN1 may be necessary for adhesion and matrix‐related signalling in FL cells, abrogating a negative signal of the PXXP domain when BAG3 is intact. We propose that BAG3 regulates CCN1 expression to regulate tumour cell adhesion and migration. Published in 2009 by John Wiley & Sons, Ltd.
Ovarian tumor in a 12‐year old female with severe hypothyroidism: A case of Van Wyk and Grumbach syndrome
Authors: Hunold Andrea , Alzen Gerhard , Wudy Stefan A. , Bluetters‐Sawatzki Renate , Landmann Eva , Reiter Alfred , Wagner Hans‐Joachim 
Published: March 2009

AbstractWe report a 12‐year‐old female presenting with an abdominal tumor. Diagnostic workup revealed giant bilateral ovarian cysts, severe hypothyroidism as well as an elevation of CA 125. We refrained from ovariectomy, which would be necessary for a malignant tumor, in view of an evident Van Wyk and Grumbach syndrome. The patient promptly responded to L‐thyroxine with complete regression of all symptoms. Hypothyroidism should be considered in the evaluation of ovarian cysts. Although the Van Wyk and Grumbach syndrome is rare, it is crucial to rule it out in order to avoid unnecessary ovarian surgery when thyroid replacement is completely sufficient. Pediatr Blood Cancer 2009;52:677–679. © 2009 Wiley‐Liss, Inc.
Qualitative and quantitative determination of hydrolysable tannins and other polyphenols in herbal products from meadowsweet and dog rose
Authors: Fecka Izabela 
Published: March 2009

AbstractIntroductionMeadowsweet and dog rose are used as herbal medicines and foodstuffs. Their biological and pharmacological properties are mainly attributed to vitamins, flavonoids and tannins known to be effective antioxidants.ObjectiveTo evaluate the distribution of hydrolysable tannins and other polyphenols in commercially available products of Filipendula ulmaria and Rosa canina.MethodologyIn order to evaluate the distribution of polyphenols, the isolation and structure elucidation of six ellagitannins (tellimagrandins I and II, rugosins A, B, D and E) along with other well‐known compounds was performed. Further high‐performance chromatographic methods (HPLC, HPTLC) were developed for qualitative and quantitative studies of phenolic acids, flavonoids and tannins in meadowsweet flowers and dog rose fruits. The analysis of linearity, limits of detection and quantification, precision and accuracy showed that the HPLC assay was sufficiently precise for content evaluation. Selection of a suitable solvent and optimisation of the sample extraction procedure were also carried out.ResultsAmounts of more than 20 polyphenols were estimated in the studied pharmaceuticals (27 products of meadowsweet and 10 products of dog rose) using a Chromolith Performance RP‐18e column and UV detection. Methyl gallate 3‐O‐β‐glucoside was identified for the first time in dog rose, while rugosins A, B and E are new meadowsweet constituents.ConclusionThe results showed that meadowsweet flowers and rose hips with seeds yielded 55.53–124.8 and 0.43–1.26 mg/g of ellagitannins, respectively. The sum of detected polyphenols was 83.88–165.68 mg/g for Filipendulae ulmariae flos and 1.21–2.66 mg/g for Rosae pseudo‐fructus cum fructibus. Copyright © 2009 John Wiley & Sons, Ltd.
Preparation and reflectance properties of new cholesteric liquid crystalline copolymers containing cholesteryl group
Authors: Guo Jinbao , Liu Fang , Zhang Lipei , Cao Hui , Yang Huai 
Published: March 2009

AbstractIn this study, a new family of side‐chain cholesteric liquid crystal copolymers derived from cholesterol substituents were synthesized. The chemical structures of the copolymers were validated by FTIR and1H NMR. A wide‐band reflective polarizer from the above copolymers with stable optical properties was developed. The pitch gradient was formed by molecular diffusion between adjacent liquid crystal layers based on these cholesteric copolymers with different pitch lengths, and the pitch gradient was further stabilized by UV crosslinking of the polymerizable monomers during the diffusion process. The stability of these systems as a function of time was investigated. The polymer network was validated by scanning electron microscopy and this network played an important role in stabilizing the pitch gradient of the system. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Use of porous ion exchange film for glucose sensing
Authors: Hotta Saori , Miyano Kazuki , Aoki Hidemitsu , Fujiwara Nobuaki , Masui Akihiko , Yano Daisaku , Sano Kazuhiko , Yamanaka Koji , Kimura Chiharu , Sugino Takashi 
Published: March 2009

AbstractA rapid response biological and chemical sensor capable of detection to the micromolar level is required for health and environmental monitoring. We have investigated the glucose sensing by using a porous ion exchanger with a three‐dimensional open‐cellular monolith structure. Glucose oxidase (GOD), a typical enzyme, is effectively immobilized on the porous anion exchange film. Addition of glucose to the immobilized GOD results in the production of gluconic acid. The impedance of the ion exchange film increases linearly with glucose concentration, which can be indirectly detected by monitoring gluconic acid concentration. The results demonstrate the potential of the porous anion exchanger as a high performance device for sensitive detection of biological substances. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Thermal conductivity and mechanical properties of aluminum nitride filled linear low‐density polyethylene composites
Authors: Gu Junwei , Zhang Qiuyu , Dang Jing , Zhang Junping , Yang Zhaoying 
Published: March 2009

AbstractTo acquire polymer composites with high thermal conductivity and mechanical properties, the aluminum nitride (AlN) microparticles modified with titanate coupling reagent of isopropyltrioleictitanate (NDZ‐105) were employed to blend linear low‐density polyethylene (LLDPE) via powder mixing method. Thermal conductive coefficient of the AlN/LLDPE composites was measured using hot disk thermal analyzer, and the thermal stability characteristics of AlN/LLDPE composites were mainly investigated via thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC). The results indicated that the use of AlN particles modified by NDZ‐105 significantly enhanced thermal conductivity and mechanical properties of AlN/LLDPE composites. The thermal conductivity coefficient λ was 1.0842 W/mk with 30% volume fraction of AlN, about three times higher than that of native LLDPE. The tensile strength of composites was maximum (17.42 MPa) with 20% mass fraction of AlN. DSC analyses results indicated that AlN had an influence on the melting temperature and the crystallinity of LLDPE. Additionally, TGA analyses showed that the thermal stability of LLDPE was significantly increased with addition of AlN. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Thermodynamic characterization of hybrid polymer blend systems
Authors: Ophir Amos , Zonder Lior , Rios Pablo F. 
Published: March 2009

AbstractA thermodynamic model was used to predict the morphology of hybrid multicomponent polymer blend systems. Two systems were studied, both including two noncompatible polymers, a third compatibilizer polymer and layered, organo‐treated clays. The polar and nonpolar contributions of the surface energies of the components of the systems were calculated using measurements of the contact angles. The morphology of the multicomponent systems and the relative position of the organo‐clays within them, were predicted by calculating the interaction energies between the different components of the system and evaluating these values according to the Vaia and Giannelis thermodynamic model for polymer melt intercalation in organically modified layered silicates. The experimental results show good correlation with the prediction that the organo‐clays will have higher affinity to the compatibilizer polymer component situated at the interface between the two noncompatible blend components. In addition, the presence of the organo‐clays in this interface was found to have a significant additional compatibilizing effect between the two polymer phases. The results presented in this work support the idea that hybrid formation via polymer melt intercalation depends mostly on energetic factors that can be determined from surface energies of polymers and organo‐modified layered silicates, also in the case of multiphase polymer system. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Synthesis of poly (vinylcatechols)
Authors: Daly William H. , Moulay Saad 
Published: March 2009

AbstractFive vinylcatechol precursors have been synthesized by either alcohol dehydration or Wittig coupling techniques. Dehydration of the appropriate sec‐phenethyl alcohol is the most efficient synthetic approach: the following monomers (yields) are reported: 5‐vinyl‐1,3‐benzodioxole, I (63%); 3,4‐dimethoxystyrene, II (45%); 2,3‐dimethoxystyrene, III (85%);6‐vinyl‐1,4‐benzodioxane.IV(65%); and4‐vinyl‐l,3‐benzodioxole, V(50%). The monomers can be converted by free‐radical techniques to polymers with molecular weights up to 95,000. Monomers I, II, IV, and V polymerized in the presence of stannic chloride; monomers I, III, and IV yielded polymers upon treatment with butyllithium. With the exception of poly IV, the blocking groups can be removed by treatment with boron trichloride followed by methanolysis to liberate poly(3‐vinyl‐ or 4‐vinylcatechol). Suprisingly, the stability of the catechol polymers depends upon the substituent distribution; poly(3‐vinylcatechol) is more stable than any polycatechol previously reported. It is soluble in methanol, autooxidizes very slowly, but can be oxidized by ceric ammonium nitrate to poly(3‐vinyl‐1,2‐benzoquinone).