bluuebunny/crossref_metadata_2025 huggingface dataset:
Dystopian Farming
Authors: Vergne Eric
Published: November 2010

In this project for Manhattan, the typology of the high‐rise is redefined. Farmers (producers) and city dwellers (consumers) are brought together in close proximity. Eric Vergne describes how rather than embracing the bucolic notion of the rural farm where food aspires to be grown in its most natural or organic state, this ‘dystopian farm’ by necessity embraces technologically advanced modes of food production such as genetic engineering. Copyright © 2010 John Wiley & Sons, Ltd.
Dross City
Authors: Kallipoliti Lydia
Published: November 2010

Dross or techno‐junk is threatening to take over and consume our cities, as exemplified by the Chinese city of Giuyu, a renowned recipient of electronic and toxic waste. Rather than reject dross as an unwanted and unsightly by‐product of urban life, Lydia Kallipoliti invokes a change in approach that calls for the need to engage with techo‐excrements, endorsing Slavoj Žižek's appeal for ‘more artificiality and less nature’. Copyright © 2010 John Wiley & Sons, Ltd.
Comings and Goings
Authors: Carter Brian
Published: November 2010

As a throwback to the idealism of the 1970s, with its contemporary layering of ‘obscure language, extreme ideas and incomprehensible rhetoric’, is EcoRedux helpful to architects? Brian Carter, Professor and Dean at the School of Architecture and Planning at the State University of New York at Buffalo, thinks so. A licensed architect in the UK, who most recently worked in practice with Arup Associates in London before taking up an academic position in North America, Carter regards environmental issues as a single but important aspect of design. He urges architects and architectural educators to make the direct engagement with the difficulties of designing and constructing buildings their priority. Copyright © 2010 John Wiley & Sons, Ltd.
Nonisothermal modeling of heat transfer inside an internal batch mixer
Authors: Bai Yun , Sundararaj Uttandaraman , Nandakumar Krishnaswamy
Published: November 2010

A nonisothermal transient process of temperature increase due to viscous heating was simulated for a 69 cm3 internal batch mixer (BM) using a computational fluid dynamics (CFD) software, Polyflow 3.9 form ANSYS, Inc., to obtain the temporal temperature distribution and characterize the heat transfer between polymer melt and mixer wall. The melt temperature obtained from simulation was verified with experiments. Starting from a uniform temperature of 463 K, when a rotation speed of 5.24 rad/s is imposed, viscous heating caused a maximum temperature rise of 3 K for a polyethylene (PE) resin, and 6 K for a polystyrene (PS) resin. The transient flow fields inside the batch mixer were characterized with velocity profiles and a mixing index parameter, which show that laminar flow dominates inside the mixer while a small percentage of elongational flow, converging flow, and recirculation flow is also present. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Optimal design of nonlinear temperature programmed reduction experiments
Authors: Heidebrecht Peter , Sundmacher Kai , Biegler Lorenz T.
Published: November 2010

We propose the application of nonconstant temperature gradients to improve the quality of temperature programmed reduction (TPR) experiments with respect to parameter estimation and model discrimination. This leads to TPR experiments with nonlinear temperature profiles (N‐TPR). To determine optimal profiles for the temperature gradient, optimal control problems are set up and solved numerically. The results show that N‐TPR experiments can be significantly better than traditional linear TPR experiments for many different scenarios. To implement these results in practice, we develop and demonstrate reduced optimization problem formulations, which can be solved faster and more reliably than the original formulation, with very similar results. © 2011 American Institute of Chemical Engineers AIChE J, 2011
Verification of filtered two‐fluid models for gas‐particle flows in risers
Authors: Igci Yesim , Sundaresan Sankaran
Published: November 2010

The effect of solid boundaries on the closure relationships for filtered two‐fluid models for riser flows was probed by filtering the results obtained through highly resolved kinetic theory‐based two‐fluid model simulations. The closures for the filtered drag coefficient and particle phase stress depended not only on particle volume fraction and the filter length but also on the distance from the wall. The wall corrections to the filtered closures are nearly independent of the filter length and particle volume fraction. Simulations of filtered model equations yielded grid length independent solutions when the grid length is ∼half the filter length or smaller. Coarse statistical results obtained by solving the filtered models with different filter lengths were the same and corresponded to those from highly resolved simulations of the kinetic theory model, which was used to construct the filtered models, thus verifying the fidelity of the filtered modeling approach. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Characterization of solvent‐spun polyester nanofibers
Authors: Duzyer S. , Hockenberger A. , Zussman E.
Published: November 2010

The aim of this study was to examine the properties of polyester nanofibers produced by the electrospinning method. Solvent‐spun nanofibers with different concentrations of poly(ethylene terephthalate) (13, 16, and 20 wt %) were produced. The morphology and surface energy of the fibers were analyzed by scanning electron microscopy and contact angle measurements. Tensile testing, dynamic mechanical analysis, and differential scanning calorimetry were carried out to characterize the thermal and mechanical properties. X‐ray diffraction and attenuated total reflection Fourier transform infrared spectroscopy tests were performed to analyze the microstructural properties. The results show that a nanoweb of the 16 wt % solution had better mechanical and thermal behaviors because of the increased molecular orientation in the amorphous structure and the narrower fiber diameter distribution in the web. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
The Variety of Microalgae Applications as a Renewable Resource
Authors: Rosello Sastre R. , Posten C.
Published: November 2010

Die biotechnologische Nutzung von Mikroalgen hat in den letzten Jahrzenten erheblich an Bedeutung gewonnen. Mikroalgen werden als eine der vielversprechendsten Quellen neuer Produkte und Anwendungen angesehen. Ziel dieses Beitrags ist es, eine Übersicht über den aktuellen technischen und kommerziellen Stand der Gewinnung von Produkten aus Mikroalgen zu geben. Während Anwendungen im Bereich von Kosmetik und Lebensmittelergänzung seit langem Standard sind, werden neue Massenprodukte für Futter‐ und Lebensmittel, Feinchemikalien und Biokraftstoffe intensiv erforscht. Zur Bedienung der sich abzeichnenden Märkte dieser Mittel‐ und Niedrigpreis‐ Produkte besteht allerdings noch Entwicklungsbedarf für die verbesserte Wirtschaftlichkeit der Mikroalgen‐Biotechnologie.
Density Functional Theory Study of Hydrogen Bonding Dimers with 4‐Pyridinecarboxylic Acid Hydrazine
Authors: Yang Qiongfen , Xie Bingyun , Li Quan , Zhao Keqing
Published: November 2010

The H‐bonding dimers of 4‐pyridinecarboxylic acid hydrazine were studied using density functional theory (DFT) at B3LYP/6‐311++G** level. The results showed that the most stable dimer D1 had two same linear NH···O hydrogen bonds, and the interaction energy between them was 51.038 kJ·mol−1 which was corrected by the basis set superposition error and zero‐point. The stretching vibration frequency of NH bond had a red shift because of the hydrogen bonds. The natural bond orbital analysis showed that each NH···O hydrogen bond in D1 had the biggest interaction stabilization energy of 69.078 kJ·mol−1. Thermodynamic analysis indicated that the formation process of D1 was exothermic and spontaneous at low and room temperatures.
Characterization and Analysis of the Electrochemical Properties of the Polyaniline Synthesized by Emulsion Polymerization in Constant Magnetic Field (0.4 T)
Authors: Ma Li , Luo Laizheng , Ma Haotian , Li Xiaofeng , Su Wenyi , Hao Shaona
Published: November 2010

A new, convenient and economical method was established firstly, which took loaded polyaniline (PANI) carbon paper as the working electrode to real‐time characterize and analyze the electrochemical properties of the PANI synthesized by emulsion polymerization in constant magnetic field (MF, 0.4 T). The characterization results of the electrochemical properties of the PANI had been proved by contrast analysis of the thermal stability of conductivity, FT‐IR, XRD and TGA of the PANI. The experimental results of cyclic voltammogram, AC impedance, Tafel curve and electrochemical stability showed that the PANI synthesized in the presence of the MF had larger redox current, smaller charge resistance, higher corrosion potential and better electrochemical stability. The PANI thermal stability of conductivity had been measured in the temperature range from 20 to 140°C, and the results showed that the PANI synthesized in the presence of the MF had better thermal stability of conductivity. The results of FT‐IR, XRD and TGA indicated that the characteristic peaks of FT‐IR spectra of the PANI synthesized in the presence of the MF shifted to the lower wavenumbers, and its crystallinity and thermal stability were also improved.
Direct Electrochemistry and Electrocatalysis Behaviors of Glucose Oxidase Based on Hyaluronic Acid‐Carbon Nanotubes‐Ionic Liquid Composite Film
Authors: Shangguan Xiaodong , Zheng Jianbin , Zhang Hongfang , Tang Hongsheng
Published: November 2010

Multi‐walled carbon nanotubes (MWNTs) were dispersed in the ionic liquid [BMIM][BF4] to form a uniform black suspension. Based on it, a novel glucose oxidase (GOx)‐hyaluronic (HA)‐[BMIM][BF4]‐MWNTs/GCE modified electrode was fabricated. UV‐vis spectroscopy confirmed that GOx immobilized in the composite film retained its native structure. The experimental results of EIS indicated MWNTs, [BMIM][BF4] and HA were successfully immobilized on the surface of GCE and [BMIM][BF4]‐MWNTs could obviously improve the diffusion of ferricyanide toward the electrode surface. The experimental results of CV showed that a pair of well‐defined and quasi‐reversible peaks of GOx at the modified electrode was exhibited, and the redox reaction of GOx at the modified electrode was surface‐confined and quasi‐reversible electrochemical process. The average surface coverage of GOx and the apparent Michaelis‐Menten constant were 8.5×10−9 mol/cm2 and 9.8 mmol/L, respectively. The cathodic peak current of GOx and the glucose concentration showed linear relationship in the range from 0.1 to 2.0 mmol/L with a detection limit of 0.03 mmol/L (S/N=3). As a result, the method presented here could be easily extended to immobilize and obtain the direct electrochemistry of other redox enzymes or proteins.
Theoretical Studies on the Electronic Structures and Optical Properties of Tri‐aryl End‐capped Terthiophene Derivatives
Authors: Wei Ni , Wang Wenliang , Yin Shiwei , Du Song , Wang Weina
Published: November 2010

The relationships between electronic structures and spectra properties are investigated by DFT/TDDFT for terthiophene derivatives, BMA‐3T (tri‐aryl amine end‐capped terthiophene), BBA‐3T (tri‐aryl amine and tri‐aryl boron end‐capped terthiophene) and BPB‐3T (tri‐aryl boron end‐capped terthiophene). The calculated results show that BMA‐3T, BBA‐3T and BPB‐3T have higher HOMO energy level and lower ionization potentials (IPs) than 3T. BMA‐3T has good hole injection ability and hole‐transport property as reported in experiment. The designed molecule of BBA‐3T and BPB‐3T own lower LUMO level and higher electron affinities (EAs) than BMA‐3T, which facilitate electron injection and improve their electron‐transport properties. Surprisingly, BPB‐3T has preferable charge equilibrium property since its hole reorganization energy (λh) is close to electron reorganization energy (λe). The ΔE (HOMO−LUMO) and Eg of these three derivatives are narrower compared to 3T, and the absorption as well as emission spectrum exhibited red‐shifts.
The Modifiable Character of a Novel Ru‐Fe‐B/ZrO2 Catalyst for Benzene Selective Hydrogenation to Cyclohexene
Authors: Liu Zhongyi , Sun Haijie , Wang Dongbin , Liu Shouchang , Li Zhongjun
Published: November 2010

A novel Ru‐Fe‐B/ZrO2 catalyst for the selective hydrogenation of benzene to cyclohexene was prepared by the chemical reduction method. A yield of cyclohexene of 57.3% was achieved at benzene conversion of 80.6% on this catalyst. The activity and yield of cyclohexene were higher than those studied previously. The structural characterizations of the catalyst were performed by TEM‐SAED, XRD, and N2‐physisorption. Moreover, cyclohexene selectivities on this catalyst increased and the activities decreased with the increase of the ZnO dosages, however, the activities increased and cyclohexene selectivities decreased with the increase of the H2SO4 dosages. Different feeding manners of H2SO4 or ZnO exerted definitely influence on the performances of this catalyst, but the degrees of influence were different due to the character of chemisorptions. Furthermore, the activity and cyclohexene selectivity on the catalysts could be reversibly modified by adding H2SO4 or ZnO into reaction slurry, which provides an easy method to recover the activity and selectivity of Ru‐Fe‐B/ZrO2 catalysts during the process of producing cyclohexene. And the modifiable mechanisms involved were speculated.
Hydrogen Bonded Supramolecular Liquid Crystalline Complex of 2,4,6‐Triarylamino‐1,3,5‐triazines with Semiperfluorinated Benzoic Acids
Authors: Cheng Xiaohong , Jin Jie , Li Quan , Dong Xing
Published: November 2010

Hydrogen bonded supramolecular complexes of 2,4,6‐triarylamino‐1,3,5‐triazines (Tn) with semiperfluorinated benzoic acids have been prepared. The mesophase behaviors of such complexes were investigated with POM (polarized optical microscopy), DSC (differential scanning calorimetry) and X‐ray diffraction. Columnar mesophase was found in the equimolar mixtures of the triazines with the semiperfluorinated benzoic acids. While the equimolar mixture of triazines with the nonfluorinated three fold alkoxy‐modified carboxylic acid was not mesogen. The mesophase formation is analyzed as the hydrogen bonding between the Tn and benzoic acid which leads to discrete dimeric supermolecule and enhances the polarity of the core region of the dimeric supermolecule; simultaneously, an increased intramolecular polarity contrast upon replacing alkyl chains by semiperfluorinated chains, which favors a microsegregation, and leads to the fromation of the columnar phase.
A Competitor‐switched Electrochemical Sensor for Detection of DNA
Authors: Fan Hao , Xing Rong , Xu Ying , Chen Miao , Wang Qingjiang , He Pingang , Fang Yuzhi
Published: November 2010

A competitor‐switched electrochemical sensor based on a generic displacement strategy was designed for DNA detection. In this strategy, an unmodified single‐stranded DNA (cDNA) completely complementary to the target DNA served as the molecular recognition element, while a hairpin DNA (hDNA) labeled with a ferrocene (Fc) and a thiol group at its terminals served as both the competitor element and the probe. This electrochemical sensor was fabricated by self‐assembling a dsDNA onto a gold electrode surface. The dsDNA was pre‐formed through the hybridization of Fc‐labeled hDNA and cDNA with their part complementary sequences. Initially, the labeled ferrocene in the dsDNA was far from surface of the electrode, the electrochemical sensor exhibited a "switch‐off" mode due to unfavorable electron transfer of Fc label. However, in the presence of target DNA, cDNA was released from hDNA by target DNA, the hairpin‐open hDNA restored its original hairpin structure and the ferrocene approached onto the electrode surface, thus the electrochemical sensor exhibited a "switch‐on" mode accompanying with a change in the current response. The experimental results showed that as low as 4.4×10−10 mol/L target DNA could be distinguishingly detected, and this method had obvious advantages such as facile operation, low cost and reagentless procedure.
Electrocarboxylation of Carbon Dioxide with Polycyclic Aromatic Hydrocarbons Using Ni as the Cathode
Authors: Yuan Gaoqing , Li Liuguan , Jiang Huanfeng , Qi Chaorong , Xie Fengchun
Published: November 2010

Using Ni cathode and Al sacrificial anode, the electrocarboxylation of polycyclic aromatic hydrocarbons (naphthalene, 5‐methylnaphthalene, anthracene, phenanthrene and 1H‐indene) with carbon dioxide (4 MPa) could be successfully performed in an undivided cell containing n‐Bu4NBr‐DMF supporting electrolyte with a constant current at room temperature, affording the corresponding trans‐dicarboxylic acids in good to excellent yields (62% –90%). Among the examined cathode materials (Ni, Pt, Ag, Cu and Zn), Ni and Pt cathodes exhibited a good catalytic activity for the electrocarboxylations. In addition, the experimental results indicated that electrolytic conditions (conducting salts, electricity, CO2 pressure and temperature) could also affect the result of the electrocarboxylation. According to the results of the electrocarboxylations and CV (cyclic voltammetry), a possible electrochemical reaction mechanism was also proposed.
High‐performance Liquid Chromatographic Analysis of Pioglitazone, Gliquidone, Rosuvastatin and Simvastatin in Formulations and Human Serum
Authors: Arayne M. Saeed , Sultana Najma , Mirza Agha Zeeshan , Shamshad Hina
Published: November 2010

Co‐administration of HMG‐CoA reductase with antidiabetic drugs is most common since antidiabetic drugs are mostly prescribed for long term therapy. In the present paper, we describe the simultaneous determination of antidiabetic (pioglitazone hydrochloride and gliquidone) in presence of statins (rosvastatin and simvastatin) in formulations and in human serum using RP‐HPLC technique. The serum samples were subjected to protein precipitation with acetonitrile prior to an HPLC analysis. At a flow rate of 1 mL·min−1 isocratic elution was employed, using mobile phase consisting of methanol/water (90:10, V:V), pH 3.50 with phosphoric acid and absorbance was recorded at 235 nm. The assay was reproducible, linear (concentration range of 5–50 μg·mL−1) and accurate. The LOD and LOQ values were 1.32, 0.28, 0.05 and 0.57 μg·mL−1 and 4.39, 0.93, 0.16 and 1.90 μg·mL−1 for pioglitazone hydrochloride, gliquidone, rosvastatin and simvastatin, respectively. There were no interfering peaks due to the excipients present in the pharmaceutical tablet and serum. Thus, the proposed method is simple and suitable for the analysis of active ingredient in tablet form and human serum.
Synthesis and Herbicidal Activity of α‐Hydroxy Phosphonate Derivatives Containing Pyrimidine Moiety
Authors: Song Hong , Mao Huiyu , Shi Deqing
Published: November 2010

A series of α‐hydroxy phosphonate derivatives containing pyrimidine moiety were designed and synthesized. Their structures were characterized by IR, 1H NMR, MS and elemental analysis. The results of preliminary herbicidal activities (in vitro) showed that some of the title compounds 2 exhibited moderate herbicidal activities against dicotyledonous weeds (Brassica campestris L), and most of compounds 2 showed better activity against dicotyledonous weeds than monocotyledonous weeds (Echinochloa crus‐galli). Further bioassays (in vivo) indicated that some of the title compounds 2 possessed good and selective herbicidal activity against amaranth pigweed (A. retroflexus) in both pre‐ and post‐emergence treatments at the dose of 1.5 kg/ha. For exmple, compounds 2a, 2b and 2e exhibited 100% inhibition against A. retroflexus in pre‐emergence treatment, and 91.7%, 98.8% and 99.5% inhibition in post‐emergence treatment at the dose of 1.5 kg/ha, respectively.
One Pot Synthesis of Amphiphilic Hyperbranched Poly‐(amino ester) and Its Dynamic Surface Activity
Authors: Gong Zhangshui , Ni Xufeng , Liang Zhenhua , Shen Zhiquan
Published: November 2010

Amphiphilic hyperbranched poly(amino ester)s with hydrophilic multi‐ethoxylated triacrylate backbone and hydrophobic long alkyl side chain were firstly synthesized via one pot Michael addition polymerization. The poly‐(amino ester) could dissolve in cold water and self‐assemble into loose micelle. Under 50–1000 ms bubble, the dynamic surface tension (DST) of the poly(amino ester) aqueous solution (0.5 wt%) still maintained in the range of 32–28 mN/m. The aqueous solutions of poly(amino ester)s with different molecular weights showed the lower critical solution temperature (LCST) in the range of 8–50°C, which could also be tuned by its pH. Capped with hydrophobic groups on the terminal units and partially neutralized with acid, the poly(amino ester)s still kept their stable dynamic surfactant behaviors, indicating promising application.
New estimation and feature selection methods in mixture‐of‐experts models
Authors: Khalili Abbas
Published: November 2010

We study estimation and feature selection problems in mixture‐of‐experts models. An$l_2$‐penalized maximum likelihood estimator is proposed as an alternative to the ordinary maximum likelihood estimator. The estimator is particularly advantageous when fitting a mixture‐of‐experts model to data with many correlated features. It is shown that the proposed estimator is root‐$n$consistent, and simulations show its superior finite sample behaviour compared to that of the maximum likelihood estimator. For feature selection, two extra penalty functions are applied to the$l_2$‐penalized log‐likelihood function. The proposed feature selection method is computationally much more efficient than the popular all‐subset selection methods. Theoretically it is shown that the method is consistent in feature selection, and simulations support our theoretical results. A real‐data example is presented to demonstrate the method.The Canadian Journal of Statistics38: 519–539; 2010 © 2010 Statistical Society of Canada
The pseudo‐GEE approach to the analysis of longitudinal surveys
Authors: Carrillo Iván A. , Chen Jiahua , Wu Changbao
Published: November 2010

Longitudinal surveys have emerged in recent years as an important data collection tool for population studies where the primary interest is to examine population changes over time at the individual level. Longitudinal data are often analyzed through the generalized estimating equations (GEE) approach. The vast majority of existing literature on the GEE method; however, is developed under non‐survey settings and are inappropriate for data collected through complex sampling designs. In this paper the authors develop a pseudo‐GEE approach for the analysis of survey data. They show that survey weights must and can be appropriately accounted in the GEE method under a joint randomization framework. The consistency of the resulting pseudo‐GEE estimators is established under the proposed framework. Linearization variance estimators are developed for the pseudo‐GEE estimators when the finite population sampling fractions are small or negligible, a scenario often held for large‐scale surveys. Finite sample performances of the proposed estimators are investigated through an extensive simulation study using data from the National Longitudinal Survey of Children and Youth. The results show that the pseudo‐GEE estimators and the linearization variance estimators perform well under several sampling designs and for both continuous and binary responses.The Canadian Journal of Statistics38: 540–554; 2010 © 2010 Statistical Society of Canada
Synthesis and Characterization of 1,3‐Dihalogeno‐2,4‐bis(2,4,6‐tri‐tert‐butylphenyl)‐cyclo‐1,3‐distiba‐2,4‐diazanes, [X–Sb(μ‐NR)]2 (X = F, Cl, Br, and I)
Authors: Lehmann Mathias , Schulz Axel , Villinger Alexander
Published: November 2010

The whole series of four‐membered rings of the type [X–Sb(μ‐NR)]2, containing alternating antimony(III) and nitrogen centers, have been synthesized and fully characterized (X = halogen, R = supermesityl = 2,4,6‐tri‐tert‐butylphenyl = Mes*) and represent rare examples of cyclo‐distiba‐diazanes. The synthesis was carried out starting from the triflate species [TfO–Sb(μ‐NR)]2, which has been generated by utilizing a new synthetic route. By Me3Si–OTf elimination, reactions of [TfO–Sb(μ‐NR)]2 with Me3Si–X yielded the halogen compounds [X–Sb(μ‐NR)]2 with the exception of the fluorine species for which an iodine/fluorine exchange reaction with AgF was successfully applied. The structures of all starting materials, along the reaction pathway, and of all halogen species were determined by single‐crystal X‐ray diffraction. While for the compounds [X–Sb(μ‐NR)]2 (X = OTf, Cl, Br, and I), a molecular structure with no significant intermolecular interactions was observed, the analogous fluorine species[F–Sb(μ‐NR)]2 displays Sb···F van der Waals interactions between the centrosymmetric dimers, which leads to a chain‐like structure in the crystal.
Efficient and Practical One‐Pot Conversions of N‐Tosyltetrahydroisoquinolines into Isoquinolines and of N‐Tosyltetrahydro‐β‐carbolines into β‐Carbolines through Tandem β‐Elimination and Aromatization
Authors: Dong Jing , Shi Xiao‐Xin , Yan Jing‐Jing , Xing Jing , Zhang Qiang , Xiao Sen
Published: November 2010

An efficient, practical, and general method for conversions of N‐tosyltetrahydroisoquinolines (N‐tosyl‐THIQs) into isoquinolines and of N‐tosyltetrahydro‐β‐carbolines (N‐tosyl‐THBCs) into β‐carbolines is described. Treatment of N‐tosyl‐THIQs or N‐tosyl‐THBCs with base in dimethyl sulfoxide afforded dihydroisoquinolines or dihydro‐β‐carbolines as intermediates, and these were then oxidized in situ by molecular oxygen to furnish isoquinolines or β‐carbolines in good to high yields. Both one‐pot conversions occurred through tandem β‐elimination and aromatization.
Akt1 deficiency in schizophrenia and impairment of hippocampal plasticity and function
Authors: Balu Darrick T. , Carlson Gregory C. , Talbot Konrad , Kazi Hala , Hill‐Smith Tiffany E. , Easton Rachel M. , Birnbaum Morris J. , Lucki Irwin
Published: November 2010

Genetic studies have associated deficient function of the serine/threonine kinase Akt1 with schizophrenia. This disorder is associated with developmental, structural, and functional abnormalities of the hippocampus that could be traced to abnormal Akt1 function. To establish a closer connection between Akt1 and hippocampal function, mice with a selective deletion of Akt1 (Akt1−/− mice) were examined for physiological and behavioral outcomes dependent on the hippocampus and associated with schizophrenia. Genetic deletion of Akt1 was associated with both impaired proliferative capacity of adult‐born hippocampal progenitors and hippocampal long‐term potentiation, indicating deficient functions of this brain region associated with neuroplasticity. Moreover, Akt1−/− mice demonstrated impairments in contextual fear conditioning and recall of spatial learning, behaviors known to selectively involve the hippocampus. Akt1−/− mice also showed reduced prepulse inhibition of the acoustic startle response, a sensorimotor gating response that is perturbed in schizophrenia. Postmortem tissue samples from patients with schizophrenia showed significant reductions of phosphorylated Akt levels in hilar neurons of the dentate gyrus, the neurogenic zone of the hippocampus. Taken together, these results implicate the Akt1 isoform in regulating hippocampal neuroplasticity and cognition and in contributing to the etiology of schizophrenia. © 2010 Wiley Periodicals, Inc.
Adult‐born neurons are necessary for extended contextual discrimination
Authors: Tronel Sophie , Belnoue Laure , Grosjean Noelle , Revest Jean‐Michel , Piazza Pier‐Vincenzo , Koehl Muriel , Abrous Djoher Nora
Published: November 2010

New neurons are continuously produced in the adult dentate gyrus of the hippocampus. It has been shown that one of the functions of adult neurogenesis is to support spatial pattern separation, a process that transforms similar memories into nonoverlapping representations. This prompted us to investigate whether adult‐born neurons are required for discriminating two contexts, i.e., for identifying a familiar environment and detect any changes introduced in it. We show that depleting adult‐born neurons impairs the animal's ability to disambiguate two contexts after extensive training. These data suggest that the continuous production of new dentate neurons plays a crucial role in extracting and separating efficiently contextual representation in order to discriminate features within events. © 2010 Wiley Periodicals, Inc.
Estimating the physical cluster‐size distribution within materials using atom‐probe
Authors: Stephenson L.T. , Moody M.P. , Gault B. , Ringer S.P.
Published: November 2010

A limiting characteristic of the atom‐probe technique is the nondetection of ions and this embodies a significant “missing information” problem in investigations of atomic clustering phenomena causing difficulty in the interpretation of any atom‐probe experiment. It is shown that the measurable cluster‐size distribution can be modeled by a mixed binomial distribution. A deconvolution method based upon expectation‐maximization (EM) algorithm is presented to obtain the original physical distribution from an efficiency‐degraded distribution, thereby providing means to calculate accurate cluster number densities from atom probe results. The accuracy of this restoration was predominantly dependent upon the detector efficiency and was proved to be highly accurate in the case of conventional atom‐probe detector efficiencies (ϵ = 57%). Such considerations and measures are absolutely necessary when the number density of clusters and small precipitates is in any way regarded as important. We conclude that limitations in detector efficiency are more limiting for cluster‐finding analyses via atom‐probe techniques than spatial resolution issues, and therefore the current endeavors for improving detector technologies are well found. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.
Effect of long‐term cattle grazing on seasonal nitrogen and phosphorus concentrations in range forage species in the fescue grassland of southwestern Alberta
Authors: Li Chunli , Hao Xiying , Willms Walter D. , Zhao Mengli , Han Guodong
Published: November 2010

Numerous studies have examined the nutritive quality of fodder plants in different seasons but few have related this seasonal response to long‐term grazing intensity. Our objective was to examine the effect of long‐term grazing on the concentrations of total nitrogen, δ15N, and total phosphorus in selected forage species from the fescue grassland near Stavely, Alberta. Plants were selected from paddocks that had been stocked at 0 (control), 2.4 (moderate grazing), and 4.8 (heavy grazing) animal unit months ha–1 for 58 years. Plant material from ten species was sampled and analyzed at monthly intervals from May to September in 2007. Total N and P concentrations were not (p > 0.05) affected by grazing for most species, but total N and P concentrations in Poa. pratensis L. were higher (p < 0.05) in grazed treatments than in the control. These results reflect an altered plant phenology through defoliation and illustrate delayed phenology in P. pratensis when grazed. The higher δ15N concentration for most species in the grazed treatments than the control is an indication of accelerated nitrogen cycling through dung and urine deposition.
Increased β‐cyanoalanine synthase and asparaginase activity in nitrogen‐deprived wheat exposed to cyanide
Authors: Machingura Marylou , Ebbs Stephen D.
Published: November 2010

The β‐cyanoalanine pathway in plants detoxifies cyanide by assimilating this metabolic poison. Given the possibility that cyanide in soil could serve as an alternate source of nitrogen for plant nutrition, this study investigated whether nitrogen deprivation of wheat seedlings altered the activity of the first enzyme of the pathway (β‐cyanoalanine synthase) or asparaginase. The results suggest that ambient, nontoxic concentrations of soil cyanide may serve as an alternate source of nitrogen for plants under nitrogen‐limiting conditions.
A combined application of thermal desorber and gas chromatography to the analysis of gaseous carbonyls with the aid of two internal standards
Authors: Kim Ki‐Hyun , Anthwal A. , Pandey Sudhir Kumar , Kabir Ehsanul , Sohn Jong Ryeul
Published: November 2010

In this study, a series of GC calibration experiments were conducted to examine the feasibility of the thermal desorption approach for the quantification of five carbonyl compounds (acetaldehyde, propionaldehyde, butyraldehyde, isovaleraldehyde, and valeraldehyde) in conjunction with two internal standard compounds. The gaseous working standards of carbonyls were calibrated with the aid of thermal desorption as a function of standard concentration and of loading volume. The detection properties were then compared against two types of external calibration data sets derived by fixed standard volume and fixed standard concentration approach. According to this comparison, the fixed standard volume‐based calibration of carbonyls should be more sensitive and reliable than its fixed standard concentration counterpart. Moreover, the use of internal standard can improve the analytical reliability of aromatics and some carbonyls to a considerable extent. Our preliminary test on real samples, however, indicates that the performance of internal calibration, when tested using samples of varying dilution ranges, can be moderately different from that derivable from standard gases. It thus suggests that the reliability of calibration approaches should be examined carefully with the considerations on the interactive relationships between the compound‐specific properties and the operation conditions of the instrumental setups.
High‐throughput quantification of isoflavones, biochanin A and genistein, and their conjugates in female rat plasma using LC‐ESI‐MS/MS: Application in pharmacokinetic study
Authors: Singh Sheelendra Pratap , Wahajuddin  , Ali Mushir M. , Jain Girish Kumar
Published: November 2010

Isoflavones containing foods and dietary supplements are widely consumed for putative health benefits (e.g. cancer chemoprevention, beneficial effects on serum lipids associated with cardiovascular health, reduction of osteoporosis, relief of menopausal symptoms). This paper describes the development and validation of a sensitive high throughput LC‐ESI‐MS/MS method for quantifying biochanin A (BCA) and genistein (GEN), and their conjugates in rat plasma. The analytes were separated on a Supelco Discovery C18 (4.6×50 mm, 5.0 μm) column under isocratic condition using acetonitrile/methanol (50:50, v/v) and 0.1% acetic acid in the ratio of 90:10 v/v as a mobile phase. The intra‐ and inter‐day assay precision ranged from 2.66 to 8.34% and 4.40 to 8.10% (RSD %), respectively, and intra‐ and inter‐day assay accuracy was between 90.67–109.25% and 95.86–106.32%, respectively, for both the analytes. The lowest quantitation limit for BCA and GEN was 0.5 ng/mL in 0.1 mL of rat plasma. The method was successfully applied to the estimation of BCA, GEN and their conjugates in rat plasma following oral administration of BCA. Circulating conjugates (glucuronides/sulfates) of BCA and GEN were quantified using enzymatic hydrolysis of plasma samples. The levels of isoflavones glucuronides/sulfates were found to be much greater than the corresponding aglycones.
A sensitive column‐switching HPLC method for aripiprazole and dehydroaripiprazole and its application to human pharmacokinetic studies
Authors: Akamine Yumiko , Yasui‐Furukori Norio , Kojima Midori , Inoue Yoshimasa , Uno Tsukasa
Published: November 2010

A simple and sensitive column‐switching HPLC‐UV method was developed for the simultaneous determination of aripiprazole, a novel atypical antipsychotic drug, and its active metabolite, dehydroaripiprazole in human plasma. Aripiprazole, its active metabolite and 7‐[5‐[4‐(3‐chloro‐2‐methylphenyl)‐1‐piperazinyl]pentyloxy]‐3,4‐dihydro‐2(1H)‐quinolinone (OPC‐14558) as an internal standard were extracted from 1 mL of plasma using a mixture of chloroform/n‐heptane (3:7, v/v), and the extract was injected into a column I (TSK BSA‐ODS/S precolumn, 5 μm) for cleanup and column II (C18 STR ODS‐II analytical column, 5 μm) for separation. Peaks were detected with an UV detector set at a wavelength of 254 nm, and the total time for chromatographic separation was ∼20 min. Mean absolute recoveries were 74.0 and 74.7% for aripiprazole and dehydroaripiprazole, respectively. Intra‐ and inter‐day CVs were less than 7.5 and 7.1% for aripiprazole concentrations ranging from 2 to 600 ng/mL, and 9.2 and 4.5% for dehydroaripiprazole concentrations ranging from 2 to 160 ng/mL. The validated concentration ranges for this method were 1–500 ng/mL and the limits of detection were 0.5 ng/mL for both aripiprazole and dehydroaripiprazole. This method was applied to pharmacokinetic study in human volunteers and patients taking aripiprazole.
Effects of intracellular organelles on the apparent diffusion coefficient of water molecules in cultured human embryonic kidney cells
Authors: Colvin Daniel C. , Jourquin Jerome , Xu Junzhong , Does Mark D. , Estrada Lourdes , Gore John C.
Published: November 2010

The apparent diffusion coefficient (ADC) of water in tissues is dependent on the size and spacing of structures in the cellular environment and has been used to characterize pathological changes in stroke and cancer. However, the factors that affect ADC values remain incompletely understood. Measurements of ADC are usually made using relatively long diffusion times; so they reflect the integrated effects of cellular structures over a broad range of spatial scales. We used temporal diffusion spectroscopy to study diffusion in packed cultured human embryonic kidney cells over a range of effective diffusion times following microtubule and actin/cytoskeleton depolymerization and disassembly of the Golgi complex. While Golgi disruption did not change ADC, depolymerization of the microtubule and the actin filament networks caused small decreases in ADC at short diffusion times only. Temporal diffusion spectroscopy provided a novel way to assess intracellular influences on the diffusion properties of tissue water. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Systematic review of pregnancy‐related carpal tunnel syndrome
Authors: Padua Luca , Pasquale Antonella Di , Pazzaglia Costanza , Liotta Giovanna A. , Librante Alessia , Mondelli Mauro
Published: November 2010

The reported incidence of pregnancy‐related carpal tunnel syndrome (PRCTS) ranges from 0.8% to 70%, and little is known of its natural history. We systematically reviewed the reported incidence of PRCTS and evaluated its natural history. We identified 214 studies that fulfilled our selection criteria. Six publications fulfilled the inclusion criteria. Five fulfilled the incidence criteria, 3 fulfilled the natural history criteria, and 2 of the 6 publications satisfied both. The reported incidence of neurophysiologically confirmed PRCTS ranged from 7% to 43%, whereas the incidence of clinically diagnosed PRCTS ranged from 31% to 62%. Symptoms persisted in more than 50% of the patients after 1 year and in about 30% after 3 years. Our review suggests that variations in the reported incidence of PRCTS largely depend on the methods used to detect this syndrome. Our data also suggest that symptoms persist in a substantial number of patients 1 or more years after delivery. Muscle Nerve 42: 697–702, 2010
Side‐chain effect of octa‐substituted POSS fillers on refraction in polymer composites
Authors: Tanaka Kazuo , Adachi Shigehiro , Chujo Yoshiki
Published: November 2010

To investigate the relationship between the chemical structures of the side chains of polyoctahedral oligomeric silsesquioxanes (POSS) fillers and the ability to decrease the refractive indices of the polymer composites, we examined the influence on the degree of polymer chain packing by the existence of the octa‐substituted POSS derivatives. The polymer composites containing methyl‐, ethyl‐, vinyl‐, isobutyl‐, octyl‐, octadecyl‐, cyclopentyl‐, and phenyl‐substituted POSS in poly(methyl methacrylate) (PMMA) were prepared. The packing coefficients of the PMMA composites containing POSS derivatives were evaluated from molar refractions and refractive indices of the films with the Lorentz–Lorenz equation. We found that the ethyl group shows the lowest values of the packing coefficients and a significant effect in reducing the refractive indices of the polymer composites. Finally, in summary, it was shown that POSS molecules can intrinsically offer to reduce a packing. In addition, less entanglement and smaller interactions between polymer chains and the substitution groups are favorable to release a packing, resulting in decreases in refractive indices. Our findings described here are the first efforts to quantitatively evaluate the ability of POSS fillers to lower refractive indices at the molecular level. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Waterborne polyesters partially based on renewable resources
Authors: Jasinska Lidia , Koning Cor E.
Published: November 2010

A new experimental approach for preparing biobased, water‐soluble polyesters (PEs) via titanium(IV) n‐butoxide‐catalyzed bulk polycondensation is presented. In the described method polymers were obtained from isosorbide, maleic anhydride and poly(ethylene glycol) (PEG). The chemical structure of the synthesized PEs was confirmed using 2D NMR spectroscopy and by titration methods. Careful analysis of 2D NMR spectra viz. correlation spectra (COSY), heteronuclear single quantum correlation spectra (HSQC) and heteronuclear multiple‐bond correlation spectra (HMBC) allowed to accomplish the complete proton assignment of isosorbide, PEG, and unsaturated acid residues in the PEs. Moreover, by using NMR spectroscopy the transformation of maleic anhydride into fumaric acid ester and the absence of maleic acid ester units in the final polymer were proven. However, during polycondensation part of the unsaturated bonds has reacted in a Michael addition with isosorbide or PEG. Gel permeation chromatography measurements revealed that the unsaturated PEs have Mn values in the range 3000–5000 g/mol. These PEs, with a low content of carboxylic acid end groups, exhibited sufficient thermal resistance for practical applications, for example, as free radical curable coatings. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis and characterization of self‐catalyzed imide‐containing pthalonitrile resins
Authors: Amir Badshah , Zhou Heng , Liu Feng , Aurangzeb Hasan
Published: November 2010

Some new amino‐ and imide‐containing phthalonitrile compounds with 1:1 molar ratio of amino group to pthalonitrile unit were successfully synthesized. The molecular structures were characterized by spectroscopic techniques. They were thermally polymerized under nitrogen/air, even in the absence of curing additives. The thermal properties of the cured products were characterized by thermogravimetric analysis and differential scanning calorimetry. The 5% weight loss temperatures ranged from 525 to 528 °C and 513 to 520 °C under nitrogen and air, respectively. Char yields (900 °C) were in the range of 62–70%. Rheometric measurements showed that the rate of the cure reaction differs for all the three monomers. The glass transition temperature advances with increasing extent of cure and disappears on postcure at 375 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Report from the Wellcome Trust/EBA “Perspectives in Clinical Proteomics” retreat – A strategy to implement Next‐Generation Proteomic Analyses to the clinic for patient benefit: Pathway to translation
Authors: Patterson Scott D. , Van Eyk Jennifer E. , Banks Rosamonde E.
Published: November 2010

Proteomics has long been thought to hold the promise of producing results of clinical utility which will influence patient treatment and outcomes. A recent Wellcome Trust/EBI meeting and retreat ‐ “Perspectives in Clinical Proteomics” ‐ brought together experts from a broad range of stakeholder groups with an interest in ensuring proteomics achieves this aim. This viewpoint presents views derived from these forums, proposing a pathway for the development of next‐generation proteomic analyses in the clinical setting from selection of candidates through to their validation and ultimate demonstration of utility through health technology assessments. Although not meant to be all encompassing, important elements for proteomics researchers to consider are presented.
Novel fluctuation‐based approach to optimization of frequency performance and degradation of nitride heterostructure field effect transistors
Authors: Matulionis A. , Liberis J. , Matulionienė I. , Šermukšnis E. , Leach J. H. , Wu M. , Morkoç H.
Published: November 2010

The fluctuation‐based technique has been used to shed light onto the physical processes responsible for the performance of nitride heterostructure field effect transistors. A non‐monotonic dependence of hot‐phonon lifetime on the density of two‐dimensional electron gas (2DEG) is found and interpreted in terms of plasmon–longitudinal‐optical‐phonon resonance. Experimental data show that the hot‐phonon lifetime acquires the shortest value in the vicinity of the resonance. At a fixed 2DEG density of the 2DEG, the resonance can be tuned in with supplied electric power. The signatures of the resonance have also been resolved in frequency performance of the transistors and their degradation. In particular, the transistor operation is the fastest and the reliability is the highest when the hot‐phonon lifetime is the shortest.

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(online colour at: www.pss‐a.com) Drain current degradation (stars 8) correlates with hot‐phonon lifetime (curve).
The influence of early science experience in kindergarten on children's immediate and later science achievement: Evidence from the early childhood longitudinal study
Authors: Saçkes Mesut , Trundle Kathy Cabe , Bell Randy L. , O'Connell Ann A.
Published: November 2010

This study explores the impacts of selected early science experiences in kindergarten (frequency and duration of teachers' teaching of science, availability of sand/water table and science areas, and children's participation in cooking and science equipment activities) on children's science achievement in kindergarten and third grade using data for 8,642 children from the Early Childhood Longitudinal Study‐Kindergarten cohort (ECLS‐K). A theoretical model that depicts the relationships between the study variables was developed and tested using structural equation modeling. Results demonstrated that availability of science materials in kindergarten classrooms facilitated teachers' teaching of science and children's participation in science activities. Likewise, the frequency and the duration of kindergarten science teaching was a significant predictor of children's science activities but not of the children's end of kindergarten science achievement scores. Children's engagement with science activities that involved using science equipment also was not a significant predictor of their end of kindergarten science achievement. However, children's participation in cooking activities was. Children's prior knowledge, motivation, socio‐economic status, and gender were all statistically significant predictors of their science achievement at the end of kindergarten and end of third grade. Results of this study indicate that early science experiences provided in kindergarten are not strong predictors of children's immediate and later science achievement. Findings of the study suggest that the limited time and nature of science instruction might be related to the limited effect of the science experiences. Implications for teacher education programs and educational policy development are discussed. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 48: 217–235, 2011