bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonparametric analysis of the influence of buyers' characteristics and personal relationships on agricultural land prices
Authors: Kostov Philip , Patton Myles , McErlean Seamus
Published: April 2008

The influence of buyer and personal relationship characteristics on agricultural land prices has received little attention in the literature. Recently, G.M. Perry and L.J. Robinson (2001) used a restricted nonlinear specification to model the influence of personal relationships (and other factors) on the implicit prices of land characteristics. In this article, we extend and generalize their specification using nonparametric neural networks. The results indicate that buyer characteristics and personal relationships affect the terms of trade in the land market, which is consistent with the social capital hypothesis. The impact of buyer characteristics and personal relationships on the implicit prices of land characteristics is, however, non‐uniform and highly nonlinear. [EconLit citations: C290, D450, Q150]. © 2008 Wiley Periodicals, Inc.
Demand for milk labels in Germany: organic milk, conventional brands, and retail labels
Authors: Jonas Astrid , Roosen Jutta
Published: April 2008

German milk brands have come under significant price pressure due to the introduction of retail labels at the lower price end and of organic milk as a premium product. This analysis provides elasticity estimates by milk types and analyzes sociodemographic determinants of demand. A censored system of German household demand for organic and conventional milk, further separated into retail‐label and brand milk, is estimated using a two‐step procedure on data from the 2000–2003 German GfK ConsumerScan Houshold Survey. Own‐price elasticities of conventional milk are around unity, but the demand for organic milk is very price‐elastic. Results suggest that the price of organic milk should be considered as an important marketing instrument. [JEL‐Code: D12, Q11]. © 2008 Wiley Periodicals, Inc.
Performance in vegetable supply chains: the role of Guanxi networks and buyer–seller relationships
Authors: Lu Hualiang , Feng Shuyi , Trienekens Jacques H. , (Onno) Omta S.W.F.
Published: April 2008

Guanxi is the lifeblood of the Chinese society. It also becomes a hot topic for achieving business success in China. The primary goal of this exploratory study is to empirically investigate the effect of guanxi networks on buyer–seller relationships and market performance for the Chinese vegetable sector. We interviewed 167 vegetable farmers (i.e., sellers) and 84 vegetable processing and exporting companies (i.e., buyers) in Jiangsu Province, P.R. China. The path analysis results reveal that guanxi networks in China directly and indirectly affect buyer–seller relationships and market performance; however, guanxi networks have different effects for vegetable sellers and buyers. Results demonstrate that vegetable sellers and buyers follow different approaches to achieve superior market performance. [EconLit citations: L100, Q130]. © 2008 Wiley Periodicals, Inc.
Greek wine firms: determinants of export performance
Authors: Karelakis Christos , Mattas Konstadinos , Chryssochoidis George
Published: April 2008

Although extensive research on the importance of the determinant factors of export performance exists, only a few studies on the wine sector have been conducted. The present study examines the export performance determinants of Greek wine firms. Primary data were collected from Greek wine exporters through a mail survey. A combination of exploratory, confirmatory, and path analyses were employed. Factors that were either similar or dissimilar to existing knowledge appear to be important for success in the wine sector. The main success dimensions, in ascending order of importance, include (a) aspects of export competitive advantage (e.g., firm export competence, export channel knowledge, product adaptation, competitive price, and distributor support), (b) environmental factors (e.g., hostility and price competition), and channel relationship antecedents (e.g., information exchange and cooperation). Implications of the findings are discussed. [EconLit citations: Q100, Q130]. © 2008 Wiley Periodicals, Inc.
Market integration and convergence to the law of one price in the North American onion markets
Authors: Susanto Dwi , Rosson C. Parr , Adcock Flynn J
Published: April 2008

The North American agricultural markets have become much more integrated; but the level of integration varies across sectors and over time. Differential tariff phasing‐out periods and remaining trade disputes are two of many factors contributing to this. This article applies panel data unit root tests to study price convergence and market integration in the North American onion markets. Commodity and variety monthly base price data for the period of 1998 to 2006 are used. Empirical results decisively suggest the existence of price convergence across markets as well as onion varieties. A two‐sample period analysis shows an increase in the speed of price convergence over time, suggesting deeper market integration as NAFTA was fully implemented. Further analysis based on a two‐country‐market basis found that U.S.–Canadian markets have experienced deeper market integration compared with U.S.–Mexican markets as well as Canadian–Mexican markets. [EconLit citations: F150, Q170]. © 2008 Wiley Periodicals, Inc.
In a big boost for the Federal Arbitration Act, the Supreme Court decides in Preston v. Ferrer that the arbitrator remains supreme
Authors: Johnson Michael E. , Loone Piret
Published: April 2008

The U.S. Supreme Court hands down the first decision from a 2007‐08 docket that now includes four arbitration cases. Michael E. Johnson and Piret Loone, of New York, who wrote the January preview of the Preston v. Ferrer case, return to analyze the Court's holding that the Federal Arbitration Act preempts a California statute that a state appeals court had said sent a management contract dispute to the state's labor commissioner before the arbitrator.
ABA task force releases mediation recommendations—and calls for more research
Authors: Bleemer Russ
Published: April 2008

The American Bar Association Section of Dispute Resolution's Task Force on Mediation Quality has completed its extensive focus group‐based investigation, and issued a report. The study shifts the dialogue about mediation evaluation to a broader view of widely used analytical techniques. But the report also acknowledges that a “substantial minority” of mediation users and lawyers still don't want mediator opinions.
Structural characterization of residual lignins isolated with cyanamide‐activated hydrogen peroxide from various organosolvs pretreated wheat straw
Authors: Xu F. , Geng Z. C. , Liu C. F. , Ren J. L. , Sun J. X. , Sun R. C.
Published: April 2008

The posttreatment of various organosolvs pretreated wheat straw with cyanamide‐activated hydrogen peroxide was studied. About 44–80% of the total residual lignin and 38–85% of the total residual hemicelluloses were released or degraded during the posttreatment with 1.8% H2O2–0.18% cyanamide at 50°C under pH 10.0 for 4 h from different aqueous organic acids or alcohols pretreated straw. The seven degraded residual lignin preparations were subjected to a comprehensive physicochemical and structural characterization by UV, FTIR, and 1H and 13NMR spectroscopy, and GPC. The nitrobenzene oxidation method was also applied to the in situ lignins. It was found that the seven residual lignin preparations contained large amounts of noncondensed syringyl and guaiacyl units, together with fewer noncondensed p‐hydroxyphenyl units, esterified p‐coumaric acid, and mainly etherified ferulic acid. All of the lignin fractions are free of associated polysaccharides and had molecular‐average weights ranging between 2980 and 3820 g mol−1. Analysis of these low molecular weight degradation products revealed an oxidation of residual lignin had occurred. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of aligned polyetherimide fiber by electrospinning
Authors: Moon SungCheal , Choi JaeKon , Farris Richard J.
Published: April 2008

Fifteen to 20 wt % polyetherimide (PEI) solutions with 1‐methyl‐2‐pyrrolidinone (NMP) were prepared. The electrical conductivity and surface tension of the solutions were determined. The fiber spinning technique of electrospinning was optimized in order to prepare unidirectionally aligned, structurally oriented nanofiber tows. The morphology of the PEI fibers was investigated using field emission scanning electron microscopy (FESEM). The well‐aligned fibers with diameters between 0.58 and 0.90 μm (FESEM) were collected by electrospinning 20 wt % PEI solutions with NMP in the range of 8–10 kV onto a target rotating with a surface velocity 9.8 m/s. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Evaluation of the curing process of polyurethane end‐capped with trialkoxysilanes by a boron trifluoride/amine complex and organotin compound
Authors: Nomura Yukihiro , Sato Shinichi , Mori Hideharu , Endo Takeshi
Published: April 2008

Polyurethanes end‐capped with some trialkoxysilanes, such as trimethoxysilane, triethoxysilane, tripropoxysilane, and tributoxysilane (silylated polyurethanes), were synthesized. Boron trifluoride/monoethylamine (BF3–MEA) complex and dibutyltin dimethoxide (DBTDM) were examined as curing catalysts for the obtained silylated polyurethanes to compare their curing speeds. It was found that BF3–MEA worked as a more efficient catalyst for the condensation reaction of the alkoxysilyl groups in the silylated polyurethanes to form the corresponding networked polyurethanes. BF3–MEA had a great advantage as one of the curing catalysts because it gave a fast curing speed for the silylated polyurethanes having long alkoxysilyl groups (ethoxy, propoxy, and butoxy) in comparison with DBTDM. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of temperature on the optical and electro‐optical properties of poly(methyl methacrylate)/E7 polymer‐dispersed liquid crystal composites
Authors: Deshmukh R. R. , Malik M. K.
Published: April 2008

Experiments on the effect of temperature on the optical and electro‐optical behaviors of polymer‐dispersed liquid crystals (PDLCs) are considered. Composite films composed of poly(methyl methacrylate) (PMMA) and the nematic‐type liquid crystal (LC) E7 were prepared by solvent casting in chloroform. The PDLC film contained droplets of E7 from 10 to 80 wt % in a PMMA matrix. Morphological studies illustrated the formation of isolated droplets of LC due to phase separation, and their homogeneous distribution increased with increasing E7 content. Thermo‐optical studies showed an increase in the nematic–isotropic transition temperature of composites, which indicated preferential solvation during the phase‐separation process. The electro‐optical characteristics were studied under the conditions of an externally applied square wave electric field with a He–Ne laser (λ = 632.8 nm) as a light source. The responses improved as the E7 content in PMMA increased. Semipermanent memory effects were noticed in composites at higher temperatures. Changes in the transmittance due to thermal variations provided the possibility of using such a device as a temperature sensor. The results obtained indicate that under these experimental conditions, the output can be controlled to the desired level by the selection of a suitable loading of LC to prepare PDLC electro‐optically active composite films with a response time on the order of only a few milliseconds. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Overlap concentration of an aqueous poly(N‐vinylcaprolactam) solution in the dynamic and static states
Authors: Foroutan Masoumeh , Khoee Sepideh , Zarrabi Mona
Published: April 2008

The overlap concentration of poly(N‐vinylcaprolactam)s (PVCLs) of low molecular weights was studied with dynamic and static methods (with viscosity and refractive‐index measurements) at three temperatures (25, 30, and 35°C). This concentration, determined by viscometry, was lower than the overlap concentration determined by refractometry. Also, the influence of the temperature and molecular weight on the viscosity and refractive index was investigated, and the opposite effect of the temperature on the viscosity and refractive index of PVCL solutions was observed. The experimental overlap concentration values were compared with those calculated with the Rao, Huggins, and Fuoss equations. The results showed that the Huggins equation is the best equation to describe the dilute solution properties of this polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Photodissociation of CH2I2 and Subsequent Electron Transfer in Solution
Authors: Saitow Ken‐ichi , Naitoh Yukito , Tominaga Keisuke , Yoshihara Keitaro
Published: April 2008

We studied photoinduced reactions of diiodomethane (CH2I2) upon excitation at 268 nm in acetonitrile and hexane by subpicosecond–nanosecond transient absorption spectroscopy. The transient spectra involve two absorption bands centered at around 400 (intense) and 540 nm (weak). The transients probed over the range 340–740 nm show common time profiles consisting of a fast rise (<200 fs), a fast decay (≈500 fs), and a slow rise. The two fast components were independent of solute concentration, whereas the slow rise became faster (7–50 ps) when the concentration in both solutions was increased. We assigned the fast components to the generation of a CH2I radical by direct dissociation of the photoexcited CH2I2 and its disappearance by subsequent primary geminate recombination. The concentration‐dependent slow rise produced the absorption bands centered at 400 and 540 nm. The former consists of different time‐dependent bands at 385 and 430 nm. The band near 430 nm grew first and was assigned to a charge‐transfer (CT) complex, CH2I2δ+⋅⋅⋅Iδ−, formed by a photofragment I atom and the solute CH2I2 molecule. The CT complex is followed by full electron transfer, which then develops the band of the ion pair CH2I2+⋅⋅⋅I− at 385 nm on the picosecond timescale. On the nanosecond scale, I3− was generated after decay of the ion pair. The reaction scheme and kinetics were elucidated by the time‐resolved absorption spectra and the reaction rate equations. We ascribed concentration‐dependent dynamics to the CT‐complex formation in pre‐existing aggregates of CH2I2 and analyzed how solutes are aggregated at a given bulk concentration by evaluating a relative local concentration. Whereas the local concentration in hexane monotonically increased as a function of the bulk concentration, that in acetonitrile gradually became saturated. The number of CH2I2 molecules that can participate in CT‐complex formation has an upper limit that depends on the size of aggregation or spatial restriction in the neighboring region of the initially photoexcited CH2I2. Such conditions were achieved at lower concentrations in acetonitrile than in hexane.
Brief functional anlaysis and treatment of elopement in preschoolers with autism
Authors: Perrin Christopher J. , Perrin Stefanie H. , Hill Elizabeth A. , DiNovi Kristin
Published: April 2008

As a result of the impact of functional analysis methodologies in identifying maintaining variables of problem behavior, considerable research has been devoted to tailoring the methodologies to be practical for an outpatient setting. The purpose of this study was (a) to use brief functional analysis (BFA) methodologies to empirically demonstrate the function of elopement exhibited by two preschoolers diagnosed with autism and (b) to develop function‐based interventions derived from the results of the BFA. In phase one, a BFA consisting of 5‐min sessions with multiple repetitions of each condition was conducted with each participant. In phase two, the efficacy of function‐based interventions was assessed using a pairwise design. Both participants' rates of elopement were differentially lower during the implementation of the function‐based intervention relative to baseline. Collectively, these results demonstrated that brief functional methodologies could be applied successfully to the assessment and treatment of elopement. Moreover, the application of BFA and the ensuing treatment in an outpatient setting extend the existing research on functional analysis. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of a supervisory intervention on assessment of interobserver agreement by educational service providers
Authors: Garrity Meredith L. , Luiselli James K. , McCollum Sara A.
Published: April 2008

Effective data collection requires routine assessment of interobserver agreement (IOA). This study evaluated a supervisory intervention to increase the frequency of IOA assessments performed by educational staff at a school for children with developmental disabilities. Intervention components included action directives, strategic posting of IOA recording forms, and performance feedback (positive reinforcement and correction). Implemented in a multiple baseline design, intervention increased IOA assessments targeting skill acquisition and behavior support plans. The study illustrates a systems‐level approach towards performance enhancement of human services personnel. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of dendritic stationary phases with surface‐bonded L‐phenylalanine derivate as chiral selector and their evaluation in HPLC resolution of racemic compounds
Authors: Yin Chuan‐Qi , He Bao‐Jiang , Huang Shao‐Hua , Zhang Jun‐Yi , Bai Zheng‐Wu , Li Zao‐Ying
Published: April 2008

Four dendrimers were synthesized on aminopropyl‐modified silica gel using methyl acrylate and ethylene diamine as building blocks by divergent method. Four generations of chiral stationary phases (CSPs) were prepared by coupling of L‐2‐(p‐toluenesulfonamido)‐3‐phenylpropionyl chloride to corresponding dendrimers. The derivatives prepared on silica gel were characterized by FT‐IR, 1H NMR, and elemental analysis. The selector loadings of these four generations of CSPs generally showed a decrease tendency with the increase of generation numbers of dendrimers. The enantioseparation properties of these CSPs were preliminarily investigated by high‐performance liquid chromatography. The CSP derived from the three‐generation dendrimer exhibited the best enantioseparation capability. Effects of the mobile phase composition and molecular structures of racemic mixtures on enantioseparation were further studied. Chirality, 2008. © 2008 Wiley‐Liss, Inc.
Discrimination of chiral guests by chiral channels: Variable temperature studies by SXRD and solid state 13C NMR of the deoxycholic acid complexes of camphorquinone and endo‐3‐bromocamphor
Authors: Tahir Mohamed I. M. , Rees Nicholas H. , Heyes Stephen J. , Cowley Andrew R. , Prout Keith
Published: April 2008

3α,12α‐Dihydroxy‐5β‐cholan‐24‐oic acid (deoxycholic acid DCA) is able to discriminate between the R‐ and S‐enantiomers of camphorquinone and endo‐(+)‐3‐bromocamphor and select only the S‐enantiomers from a racemic mixture. DCA forms novel well ordered 1:1 adducts with (1S)‐(+)‐camphorquinone and (1S)‐endo‐(‐)‐3‐bromocamphor, both of which have been characterized by single crystal X‐ray diffraction (SXRD). When DCA is cocrystallized with (RS)‐camphorquinone and (RS)‐endo‐3‐bromocamphor, 1:1 adducts of the S‐enantiomers are produced together with crystals of the free racemic guest. In contrast, in the absence of (1S)‐(+)‐camphorquinone, DCA forms a 2:1 adduct with (1R)‐(−)‐camphorquinone. In this 2:1 adduct the guest is disordered at ambient temperature and undergoes a phase change in the region 160–130 K similar to that observed for the ferrocene adduct, but with only partial ordering of the guest. The SXRD structure of the low temperature form and the variable temperature 13C CP/MAS NMR are reported. Cocrystallizing DCA with (1R)‐endo‐(+)‐3‐bromocamphor gives the free guest and a glassy solid. Chirality, 2008. © 2008 Wiley‐Liss, Inc.
Analysis of the mechanism of asymmetric amplification by chiral auxiliary trans‐1,2‐diaminocyclohexane bistriflamide
Authors: Asakura Kouichi , Isoda Yuuki , Kondepudi Dilip K. , Yamaguchi Tomohiko
Published: April 2008

Asymmetric amplification is a phenomenon in which the enantiomeric excess (ee) of a product is higher than that of a chiral auxiliary for a catalyst. We analyzed the mechanism of asymmetric amplification observed in the addition of diethylzinc (Et2Zn) to benzaldehyde (PhCHO) to synthesize 1‐phenyl‐1‐propanol in the presence of trans‐1,2‐diaminocyclohexane bistriflamide (DCBF) and titanium tetraisopropoxide (TIOP). In a manner similar to the reaction in which 1‐piperidino‐3,3‐dimethyl‐2‐butanol is a chiral auxiliary for the catalyst, when asymmetric amplification was observed, the ee of the product varied as the reaction progressed. The mechanisms of variation in ee in the two reactions, however, were different. No asymmetric amplification was observed when TIOP and PhCHO were added to a mixture of DCBF and Et2Zn, while the ee of the product was always higher than that of DCBF when PhCHO and Et2Zn were added to a mixture of DCBF and TIOP. In the latter case, the product ee decreased as the reaction progressed. The results indicate that DCBF forms inactive heterochiral complex causing an increase in the ee of DCBF in the solution, which is the chiral auxiliary for the catalyst. But the complex is not very stable and gradually dissociates due to the reaction with Et2Zn. As a result, the asymmetric amplification decreases as the reaction progresses. Chirality, 2008. © 2008 Wiley‐Liss, Inc.
Rock around the Ring: An Experimental and Theoretical Study of the Molecular Dynamics of Stannyltriphospholes with Chiral Tin Substituents
Authors: Hofmann Martin , Clark Tim , Heinemann Frank W. , Zenneck Ulrich
Published: April 2008

The reaction of diphenyltin dichloride with enantiopure Grignard reagents prepared in situ leads to diphenyltin chlorides 7a–e, which contain chiral organyl substituents. The 2‐bornyl derivative 7a forms a mixture of exo and endo isomers and the (–)‐menthyl derivative 7b yields a mixture of epimers, whereas the cis‐ and trans‐myrtanyl complexes 7c and 7d and the m‐(2‐bornyl‐2‐ene)phenyl species 7e form only one enantiomer as the tin atom is separated from the next stereogenic centre by a methylene or m‐phenylene group. The target chirally modified 1‐(triorganylstannyl)‐1,2,4‐triphospholes 2a–e are accessible from 7a–e by treatment of the latter with the salt (3,5‐di‐tert‐butyl‐1,2,4‐triphospholyl)sodium (Na5) in good yield. As for 7c–e, complexes 2c–e exhibit enantiopure organyl tin substituents that combine with the planar chiral 1,2,4‐triphosphole moiety to form diastereomers. X‐ray diffraction studies on crystalline phases of 2a,b,d and 7b,c confirm the stereochemical interpretations of their spectroscopic data with the help of absolute structure parameter determinations. Dynamic NMR spectroscopy experiments with these compounds demonstrate for the first time a facile stannyl group shift between the two adjacent P atoms (P1 and P2) of the heterocycles that includes ring inversion through a planar transition state (Ti). In line with the NMR spectroscopic results for 2a–e, density functional calculations with the simplified model compound (trimethylstannyl)‐1,2,4‐triphosphole (9) point to 1‐(trimethylstannyl)‐1,2,4‐triphosphole (9a) as the global energetic minimum for 9 and an almost isoenergetic 1,2‐shift and ring inversion as the main epimerisation processes of the two enantiomers of 9a.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Monomeric Boron and Tin(II) Heterocyclic Derivatives of 1,8‐Diaminonaphthalenes: Synthesis, Characterization and X‐ray Structures
Authors: Jiménez‐Pérez Víctor M. , Muñoz‐Flores Blanca M. , Roesky Herbert W. , Schulz Thomas , Pal Aritra , Beck Tobias , Yang Zhi , Stalke Dietmar , Santillan Rosa , Witt Michael
Published: April 2008

The reaction of the diaminonaphthalene dilithium salt(THF)2Li2[(NSiMe3)2C10H6] with BX3 (X = Cl, Br) in hexane provides the monomeric compounds BX[(NSiMe3)2C10H6] [3 (X = Cl), 4 (X = Br)] with a tricoordinate boron atom. Attempts to reduce 3 and 4 with lithium, sodium, potassium or sodium/potassium alloy with the intention to isolate a boranide resembling a carbene were unsuccessful. However, the diaminonaphthalene dilithium salt (THF)2Li2[(NSi‐iPr3)2C10H6] (2) reacts with SnCl2 in THF to provide the carbene analog 5. Compounds 2, 3 and 5 were characterized by single‐crystal X‐ray structure analysis. The structures of 3 and 5 show the naphthalene backbone to be nearly planar, while the heterocycles in 3 and 5 containing boron and tin atoms, respectively, have torsion angles (3: 30.06°; 5: 37.27°) with respect to the naphthalene plane. The boron atom has a trigonal‐planar environment, and the stannylene tin–nitrogen bonds form a very acute N–Sn–N angle of 92.2°.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Stereoselective Synthesis of a cis‐1,2‐Dialkylcyclopentane Building Block and Its Application in Isoprostane Synthesis (5‐ent‐F2c‐IsoP)
Authors: Elsner Petteri , Jetter Peter , Brödner Kerstin , Helmchen Günter
Published: April 2008

The all‐cis substituted cyclopentane 3a, an analogue of the Corey lactone, has been prepared from a readily available nortricyclanone derivative by a five‐step sequence in an overall yield of 34 %. This chiral building block has been applied in total syntheses of two diastereomeric isoprostanes belonging to the 5‐F2 family: ent‐5‐F2c‐IsoP (ent‐1) and 5‐epi‐ent‐5‐F2c‐IsoP (ent‐2). Key features of the syntheses are the introduction of the two unsaturated alkyl side chains through an E‐selective Horner–Wadsworth–Emmons reaction with the base‐sensitive syn‐aldehyde 10, along with a Z‐selective Wittig olefination.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Determination of Trace Manganese by Square‐Wave Stripping Voltammetry
Authors: Wang Shujie , Ye Baoxian
Published: April 2008

A novel method of determining trace manganese by square‐wave stripping voltammetry with simultaneous plating mercury electrode is described in this paper. Well‐defined stripping peaks of manganese are obtained in H3BO4‐NaOH buffer (pH 8.0) and peak currents are in good linear relationship with manganese concentrations in two ranges: from 0.36 nM to 36 nM and from 73 nM to 909 nM. The obtained detection limit is 0.18 nM and relative standard deviation is 2.3% (n=7) under a predeposition time of 90 s. This proposed method has been used for the determination of trace manganese in real plasma samples with satisfiable results and good matching with the results of graphite furnace atomic absorption spectrometry.
Biomolecule‐Doped Organic/Inorganic Hybrid Nanocomposite Film for Label‐Free Electrochemical Immunoassay of α‐1‐Fetoprotein
Authors: Hong Chenglin , Yuan Ruo , Chai Yaqin , Zhuo Ying
Published: April 2008

A new electrochemical immunosensor for the detection of α‐1‐fetoprotien (AFP) was developed based on AFP antibody (anti‐AFP)‐functionalized organic/inorganic hybrid nanocomposite membrane. To fabricate such a hybrid composite membrane, 3,4,9,10‐perylenetetracarboxylic acid‐bound thionine molecules (PTCTH) were initially doped into titania colloids (TiO2), and then gold nanoparticles and anti‐AFP were immobilized onto the composite film in turn. Comparison with the electrode fabricated only with thionine not 3,4,9,10‐perylenetetracarboxylic acid, the immunosensor with PTCTH exhibited high sensitivity and fast electron transfer. The presence of gold nanoparticles provided a good microenvironment for the immobilization of biomolecules, enhanced the surface coverage of protein, and improved the sensitivity of the immunosensor. The modified process was characterized by scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The surface topography of the membrane was investigated by scanning electron microscopy (SEM). Under optimal conditions, the proposed immunosensor exhibited a wide linear range from 2.5 to 200.0 ng/mL towards AFP with a detection limit of 0.5 ng/mL (S/N=3). The stability, reproducibility and precision of the immunosensor were acceptable. Comparison with the conventional enzyme‐linked immunosorbent assay (ELISA), the present method did not require more labeled procedures and washing steps. Significantly, the detection methodology provides a promising approach for other proteins or biosecurities.
Electrochemically Induced Modulation of the Catalytic Activity of a Reversible Redoxsensitive Riboswitch
Authors: Strohbach Denise , Turcu Florin , Schuhmann Wolfgang , Müller Sabine
Published: April 2008

Over the past decade, RNA conformation has been shown to respond to external stimuli. Thus, dependent on the presence of a high affinity ligand, specifically designed ribozymes can be regulated in a classical allosteric way. In this scenario, a binding event in one part of the RNA structure induces conformational changes in a separated part, which constitutes the catalytic centre. As a result activity is switched on (positive regulation) or off (negative regulation). We have developed a hairpin aptazyme responding to flavine mononucleotide (FMN). Ribozyme activity is dependent on binding of FMN and thus is switched on in the presence of FMN in its oxidized form. Under reducing conditions, however, FMN changes its molecular geometry, which is associated with loss of binding and consequently down‐regulation of ribozyme activity. While in previous experiments sodium dithionite was used for reduction of FMN, we now present an assay for electrochemically induced activity switching. We have developed an electrochemical microcell that allows for iterative cycles of reduction/oxidation of FMN in an oxygen free atmosphere and thus for reversible switching of ribozyme activity. The reaction proceeds in droplets of 3 to 10 μL at micro‐ to nanomolar concentrations of the reaction components.
Potentiometric DNA Sensor Based on Electropolymerized Phenothiazines for Protein Detection
Authors: Evtugyn Gennady A. , Porfireva Anna V. , Hianik Tibor , Cheburova Maria S. , Budnikov Herman C.
Published: April 2008

Novel method of potentiometric detection of DNA‐protein interactions has been proposed. For this purpose, polymeric phenothiazine dyes, methylene blue (MB) and methylene green (MG), were electrochemically deposited onto the glassy carbon electrode and covered with double stranded DNA (dsDNA) as a target for antibodies (DNA‐sensor) or DNA aptamer specific to human α‐thrombin (aptasensor). The biosensors were consecutively incubated at pH 7.5 and 3.0 and the difference in potentials, ΔE, was used as a measure of protein concentration. The potentiometric DNA‐sensors were tested in standard serum of autoimmune disease patients (systemic lupus erythemathosus (SLE) and autoimmune thyroidites). It was shown, that the ΔE value of DNA‐sensor depends on the dilution of serum in the range from 1 : 1 to 1 : 100. Nonthermostated serum exhibited bell‐shape dependence of ΔE on serum dilution due to interfering effect of serine proteins at maximum dilution between 1 : 20 and 1 : 50. For SLE serum thermostated at 56 °C the ΔE linearly decreased as a function of serum dilution and reached saturation at dilution 1 : 20. Similarly the changes in the potential of aptasensor allowed us to determine the α‐thrombin in the range from 1 nM to 1 μM. The Faradic impedance spectra measured at presence of redox probe [Fe(CN)6]4−/3− revealed changes in the resistance and capacitance attributed to the shielding effect of anti‐DNA antibodies and an increase in the electron transfer. The developed potentiometric biosensors can be used for preliminary diagnostics of autoimmune diseases and thrombin detection with sensitivity comparable to traditional methods. The developed assay is, however simpler and cheaper in comparison with commonly used methods.
Effect of blockage on free vibration of a circular cylinder at low Re
Authors: Prasanth T. K. , Mittal S.
Published: April 2008

The effect of the blockage on vortex‐induced vibrations of a circular cylinder of low non‐dimensional mass (m*=10) in the laminar flow regime is investigated in detail. A stabilized space–time finite element formulation is utilized to solve the incompressible flow equations in primitive variables form in two dimensions. The transverse response of the cylinder is found to be hysteretic at both ends of synchronization/lock‐in region for 5% blockage. However, for the 1% blockage hysteresis occurs only at the higher Re end of synchronization/lock‐in region. Computations are carried out at other blockages to understand its effect on the hysteretic behavior. The hysteresis loop at the lower Re end of the synchronization decreases with decrease in blockage and is completely eliminated for blockage of 2.5% and less. On the other hand, hysteresis persists for all values of blockage at the higher Re end of synchronization/lock‐in. Although the peak transverse oscillation amplitude is found to be same for all blockage (∼0.6D), the peak value of the aerodynamic coefficients vary significantly with blockage. The r.m.s. values show lesser variation with blockage. The effect of streamwise extent of computational domain on hysteretic behavior is also studied. The phase between the lift force and transverse displacement shows a jump of almost 180° at, approximately, the middle of the synchronization region. This jump is not hysteretic and is independent of blockage. Copyright © 2008 John Wiley & Sons, Ltd.
Differential involvement of TNFα in hypoxic suppression of astrocyte glutamate transporters
Authors: Boycott Hannah E. , Wilkinson Jenny A. , Boyle John P. , Pearson Hugh A. , Peers Chris
Published: April 2008

Transporter‐mediated glutamate uptake is a principal function of astrocytes. Our previous studies have shown that this process is compromised under hypoxic conditions through the NF‐κB mediated inhibition of expression of the glutamate transporters EAAT‐1 and EAAT‐2. Here, we demonstrate that identical conditions of hypoxia (1% O2, 24 h) lead to a dramatic increase in TNFα production from astrocytes without altering their viability. This hypoxia‐evoked production of TNFα was prevented in the presence of any of three mechanistically distinct NF‐κB inhibitors. Exogenous application of TNFα was without effect on EAAT‐1 expression as determined by Western blotting, but mimicked the effects of hypoxia to suppress expression of EAAT‐2. Furthermore thalidomide, which prevents TNFα production, was without effect on hypoxic suppression of EAAT‐1 but prevented hypoxic suppression of EAAT‐2. These data indicate that regulation of glutamate transporter expression in astrocytes by hypoxia is subtype specific. Regulation of both EAAT‐1 and EAAT‐2 is mediated by NF‐κB, and this transcriptional regulator is also required for increased production of TNFα. However, while TNFα is essential for hypoxic suppression of EAAT‐2, hypoxic modulation of EAAT‐1 expression is unaffected by this cytokine. © 2008 Wiley‐Liss, Inc.
Differential neutrophil infiltration contributes to regional differences in brain inflammation in the substantia nigra pars compacta and cortex
Authors: Ji Kyung‐Ae , Eu Mi Young , Kang Seung‐Hee , Gwag Byoung Joo , Jou Ilo , Joe Eun‐Hye
Published: April 2008

Brain inflammation is a suggested risk factor for neurodegenerative disease. Interestingly, severe inflammation in the substantia nigra pars compacta (SNpc) accelerates the onset and progression of Parkinson's disease. In this study, we examined the underlying mechanisms of severe inflammation in the SNpc by comparing the inflammatory process with that in the cortex. In intact brain, the densities of CD11b+ microglia were similar in the SNpc and cortex. However, lipopolysaccharide injection enhanced the CD11b+ cell number in the SNpc, but not in the cortex. Previously, we reported that CD11b and myeloperoxidase (MPO) double‐positive neutrophils infiltrate the SNpc following LPS injection (GLIA 55:1577–88). Notably, the MPO+ neutrophil number increased dramatically in the SNpc, but only slightly in the cortex. The extent of neutrophil infiltration appeared to correlate with neuronal damage. We confirmed that loss of neurons in the SNpc was significantly reduced in neutropenic rats versus normal rats following LPS injection. In addition, the densities of astrocytes were much lower in the intact SNpc, compared with the cortex. Furthermore, after LPS injection, damage of endothelial cells and astrocytes, and blood–brain barrier (BBB) permeability was more pronounced in the SNpc. These results collectively suggest that excessive neutrophil infiltration and environmental factors, such as lower astrocyte density and higher BBB permeability, contribute to severe inflammation and neuronal death in the SNpc. © 2008 Wiley‐Liss, Inc.
Cortical responses to self and others
Authors: Hodzic Amra , Muckli Lars , Singer Wolf , Stirn Aglaja
Published: April 2008

The extrastriate body area (EBA) is one among the multiple, functionally specialized regions of the human visual cortex exhibiting modulation by body‐related stimuli. Here we investigate whether activation patterns differ for the perception of one's own body and the bodies of others. We used functional magnetic resonance imaging to identify body‐related brain areas and to see how these areas differentiate between images of one's own body and those of others in the absence of facial or motion cues. Whole brain explorative group‐level analysis identified body‐related blood oxygen level dependent (BOLD) signal enhancement in five regions of the right and in one region of the left hemisphere (right: in the extrastriate visual and parietal cortex and in the precentral gyrus, left: in the extrastriate visual cortex). General linear model group‐level random effects analysis of the self–other contrast revealed self‐related responses in the extrastriate and parietal regions in the right hemisphere but also in the right middle frontal gyrus. These results suggest the existence of a cortical network for the extraction of body‐related information and another cortical network for the extraction of self‐related body information. The two networks partially overlap in the right superior and inferior parietal cortices, but are clearly segregated in the extrastriate visual cortex and in the middle frontal gyrus. In addition, we report that the classical EBA is only involved in the analysis of body‐related information but not in the assignment of body identity. The latter appears to be accomplished by a network in right hemisphere comprising the fusiform body area, regions of the superior parietal lobe, the inferior parietal cortex, and the middle frontal gyrus. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Relevance of clinical trials in acute myeloid leukaemia
Authors: Tsimberidou Apostolia M. , Estey Elihu
Published: April 2008

Patients with newly diagnosed acute myeloid leukaemia (AML) are increasingly being enrolled in clinical trials sponsored by pharmaceutical companies or the National Cancer Institute. These trials routinely exclude patients who are less likely to respond (LLTR), e.g. those with Zubrod performance status >2 and levels of bilirubin or creatinine ≥2.0 mg/dL. Here we examine rates of enrollment of LLTR patients in clinical trials over the past 16 years. Overall, 2323 adults with newly diagnosed AML (excluding acute promyelocytic leukaemia) were registered on clinical trials from 1991 to 2006. LLTR patients constituted a significantly smaller proportion of the patients enrolled from 1999 to 2006 than from 1991 to 1998 (p < 0.0001, considering all patients and patients 60 years or older). While 54% of patients considered ‘more likely to respond’ (MLTR) (i.e. those with performance status <3, bilirubin <2.0 mg/dL and creatinine <2.0 mg/dL) were enrolled in these studies from 1999 to 2006, only 36% of LLTR patients were enrolled during this period (p < 0.0001). Our results suggest that newer clinical trials may be less applicable to LLTR patients than previous trials. There is a need for clinical trials specific to the LLTR population, the group most in need of novel therapies. Copyright © 2008 John Wiley & Sons, Ltd.
Caspase polymorphisms and genetic susceptibility to multiple myeloma
Authors: Hosgood H. Dean , Baris Dalsu , Zhang Yawei , Zhu Yong , Zheng Tongzhang , Yeager Meredith , Welch Robert , Zahm Shelia , Chanock Stephen , Rothman Nathaniel , Lan Qing
Published: April 2008

Multiple myeloma is a haematological malignency, characterized by clonal expansion of plasma cells. However, little is known about the cause of multiple myeloma. Cancer cells must avoid apoptosis to ensure unregulated tumour formation and growth. The highly conserved caspase cascade is essential to the regulation of the apoptotic pathway. To examine if five single nucleotide polymorphisms (SNPs) in four caspase genes [CASP3 Ex8‐280 C > A (rs6948), CASP3 Ex8 + 567 T > C (rs1049216), CASP8 Ex14‐271 A > T (rs13113), CASP9 Ex5 + 32 G > A (rs1052576), CASP10 Ex3‐171 A > G (rs39001150)] alter multiple myeloma risk, we conducted a population‐based case‐control study of women (128 cases; 516 controls) in Connecticut. Compared to individuals with the TT genotype of CASP3 Ex8 + 567 T > C, subjects with the CC genotype had a five‐fold decreased risk of multiple myeloma (odds ratio (OR)CC = 0.2, 95% confidence interval (CI) = 0.0–1.0). Further, individuals with the AG and AA genotypes of CASP9 Ex5 + 32 G > A also experienced a decreased risk of multiple myeloma (ORAG = 0.8, 95% CI =  0.5–1.3; ORAA = 0.5, 95% CI = 0.3–0.9; p‐trend = 0.02). While no previous study has evaluated the association between caspase genes and multiple myeloma, studies have found associations with lung, breast, esophageal, gastric, colorectal and cervical cancers. Our parallel study of non‐Hodgkin lymphoma, which utilized the same controls, found strong evidence that caspase genes play a key role in lymphogenesis. The protective associations observed in two key caspase genes suggest that genetic variation in CASP genes may play an important role in the aetiology of multiple myeloma. Copyright © 2008 John Wiley & Sons, Ltd.
Interactive silences within spontaneous early infant–father ‘dialogues’
Authors: Kokkinaki Theano
Published: April 2008

The present longitudinal and naturalistic study aims to investigate infants' and fathers' facial expressions of emotions during pauses preceding and following spontaneous early infant–father conversation. Studying emotional expressions in the course of pauses in early infant–father interaction is important because it may extend our knowledge on how, without being able to speak, infants begin communication and develop a capacity to share understanding of what they and Significant Others (such as fathers) mean by what they do. Eleven infant–father dyads from Crete, Greece, were observed during their natural interactions at home from the second to the sixth month of life. The microanalysis of fathers' and infants' facial expressions of emotions provided evidence that: (a) in the course of pauses preceding and following early infant–father conversation, either the infant is interested in the father while the latter expresses pleasure to the infant, or the infant expresses external interest while the father is interested in the infant, (b) infants seem to attune their descending and stable emotional intensity to the same direction as their father's emotional intensity, (c) infants and fathers remain consistent in their emotional expression in the beginning and at the end of the pause, and (d) infant and paternal pleasure and interest did not change significantly across the nine age points of this study. Exploratory analysis of the relationship of paternal and infant emotional expressions across infants' birth order provided evidence of certain differences and similarities. It is proposed that pausal interruptions preceding and following free early infant–father ‘dialogues’ constitute interactive silences, since in their course there is evidence of inter‐subjective emotional coordination and intra‐subjective regulation of emotion. Copyright © 2008 John Wiley & Sons, Ltd.
Periostin, secreted from stromal cells, has biphasic effect on cell migration and correlates with the epithelial to mesenchymal transition of human pancreatic cancer cells
Authors: Kanno Atsushi , Satoh Kennichi , Masamune Atsushi , Hirota Morihisa , Kimura Kenji , Umino Jun , Hamada Shin , Satoh Akihiko , Egawa Shinichi , Motoi Fuyuhiko , Unno Michiaki , Shimosegawa Tooru
Published: April 2008

Periostin is a secretory protein that has been suggested to function as a cell adhesion molecule and promote the invasiveness or growth rate of tumors. However, little is known about the association of its expression and epithelial to mesenchymal transition (EMT), which is considered to play a crucial role in cancer cell metastasis. Thus, the authors investigated whether periostin could be involved in the process of EMT and the role of this gene in pancreatic cancer development. The expression of periostin was observed mainly in stromal cells but very little in cancer cells by immunohistochemistry and real‐time RT‐PCR. In vitro, pancreatic stellate cells (PSCs) exhibited a much higher basal expression of periostin compared with cancer cells. Periostin secreted in the supernatant from 293T cells that expressed periostin (approximately 150 ng/ml) inhibited the migration of pancreatic cancer cells. Coculture assay revealed that periostin expression in PSC was induced by pancreatic cancer cells. To assess the direct role of periostin in pancreatic cancer cells, the authors generated pancreatic cancer cell lines that stably express periostin. The induced expression of periostin (to 150 ng/ml) altered the morphology of cancer cells, changing them from mesenchymal to epithelial phenotypes with the induction of epithelial markers and a reduction of mesenchymal markers, and showed reduced cell migration in vitro and formed smaller tumors as well as suppressed metastasis in vivo. On the other hand, high concentration of recombinant periostin (1 μg/ml) promoted cell migration with AKT activation. The findings suggest that periostin has biphasic effect on the development of pancreatic cancer. © 2008 Wiley‐Liss, Inc.
Lymphoma presenting as an echogenic periportal mass: Sonographic findings
Authors: Kim Honsoul , Kim Ki Whang , Park Mi‐Suk , Kim Hyunki
Published: April 2008

Abdominal lymphoma usually appears as homogeneous, markedly hypoechoic masses on sonography. We report a case of primary lymphoma presenting as an extrahepatic and intrahepatic periportal echogenic mass encasing the hepatic vessels. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008.