bluuebunny/crossref_metadata_2025 huggingface dataset:
Latent cationic palladium(II) phosphine carboxylate complexes for norbornene polymerization
Authors: Thirupathi Natesan , Amoroso Dino , Bell Andrew , Protasiewicz John D.
Published: November 2008

The catalytic efficacy of trans‐[(R3P)2Pd(O2CR′)(LB)][B(C6F5)4] (1) (LB = Lewis base) and [(R3P)2Pd(κ2‐O,O‐O2CR′)][B(C6F5)4] (2) for mass polymerization of 5‐n‐butyl‐2‐norbornene (Butyl‐NB) was investigated. The nature of PR3 and LB in 1 and 2 are the most critical components influencing catalytic activity/latency for the mass polymerization of Butyl‐NB. Further, it was shown that 1 is in general more latent than 2 in mass polymerization of Butyl‐NB. 5‐n‐Decyl‐2‐norbornene (Decyl‐NB) was subjected to solution polymerization in toluene at 63(±3) °C in the presence of several of the aforementioned palladium complexes as catalysts and the polymers obtained were characterized by gel permeation chromatography. Cationic trans‐[(R3P)2PdMe(MeCN)][B(C6F5)4] [R = Cy (3a), and iPr (3b)] and trans‐[(R3P)2PdH (MeCN)][B(C6F5)4] [R = Cy (4a), and iPr (4b)], possible products from thermolysis of trans‐[(R3P)2Pd(O2CMe)(MeCN)][B(C6F5)4] [R = Cy (1a) and iPr (1g)], as well as trans‐[(R3P)2Pd(η3‐C3H5)][B(C6F5)4] [R = Cy (5a), and iPr (5b)], were also examined as catalysts for solution polymerization of Decyl‐NB. A maximum activity of 5360 kg/(molPd h) of 2a was achieved at a Decyl‐NB/Pd: 26,700 ratio which is slightly better than that achieved with 5a [activity: 5030 kg/(molPd h)] but far less compared with 4a [activity: 6110 kg/(molPd h)]. Polydispersity values indicate a single highly homogeneous character of the active catalyst species. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 103–110, 2009
Synthesis and properties of monodisperse multi‐triarylamine‐substituted oligothiophenes and 4,7‐bis(2′‐oligothienyl)‐2,1,3‐benzothiadiazoles for organic solar cell applications
Authors: XIA Ping Fang , Lu Jianping , Kwok Chi Ho , Fukutani Hiroshi , Wong Man Shing , Tao Ye
Published: November 2008

Two novel series of monodisperse multi‐triarylamine‐substituted oligothiophenes, G2‐OT(n)‐G2 with thiophene unit (n) varying from 6 to 8, and 4,7‐bis(2′‐oligothienyl)‐2,1,3‐benzothiadiazoles G2‐OT(n)BTD‐G2 (n = 2, 4, 6) have been synthesized by the Suzuki coupling reactions. With an elongation of alkyl‐substituted oligothiophene core or an incorporation of benzothiadiazole into the central core, the absorption and emission spectra of G2‐OT(n)‐G2 and G2‐OT(n)BTD‐G2 series red‐shift substantially with the optical gap reducing to 1.95 eV for G2‐OT(6)BTD‐G2. Alkyl‐substitution onto oligothiophene backbone not only improves the solubility of the highly extended dendrimers but also renders coplanarity of the dendritic oligothiophene backbone at the excited state, which results in the enhancement of fluorescence quantum efficiency. The bulk heterojunction solar cells using these newly synthesized dendritic oligothiophenes as a donor material and [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) as an acceptor material were fabricated and investigated which showed an increase in device performance as compared with those of the lower homologues. On increasing the loading of PCBM from 1.5 to 3 times in the active layer, there was also an enhancement in device performance with power conversion efficiencies of as‐fabricated solar cells increasing from 0.18% to 0.32%. In addition, proper annealing procedure could significantly improve the device performance of the dendrimer‐based photovoltaic cell. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 137–148, 2009
Proton conducting polymers containing 1H‐1,2,3‐triazole moieties
Authors: Martwiset Surangkhana , Yavuzcetin Ozgur , Thorn Michael , Versek Craig , Tuominen Mark , Coughlin E. Bryan
Published: November 2008

Polyacrylates containing a different number of 1H‐1,2,3‐triazole groups per repeat unit have been synthesized via conventional free radical polymerization. These polymers were characterized by nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Proton conductivity measurements were made using impedance spectroscopy. Introduction of more than one triazole per repeat unit did not result in an increase in conductivity as there was an accompanying increase in glass transition temperature (Tg). A maximum conductivity of 17.5 μS/cm was obtained at 200 °C under anhydrous condition. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 188–196, 2009
Biodegradable hyperbranched polyesters derived from 1,1,1‐tris(hydroxymethyl)ethane
Authors: Kricheldorf Hans R. , Behnken Gesa
Published: November 2008

Low molar mass hyperbranched polyesters were prepared by polycondensation of 1,1,1‐tris(hydroxymethyl)ethane and various dimethyl esters of aliphatic dicarboxylic acids in bulk. The usefulness of nontoxic bismuth salts as transesterification catalysts for these polycondensations was studied. The maximum conversion increased, and the reaction time decreased in the following sequence of increasing reactivity: dimethyl sebacate < adipate < glutarate < succinate. Regardless of the monomer combination, gelation occurred at conversions > 91.5%. The hyperbranched structure was proven by 1H NMR spectroscopy and the absence of cyclic elements by MALDI‐TOF mass spectrometry. Quantitative acylation of all CH2OH groups was achieved with an excess of acetic anhydride or methycrylic anhydride. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 231–238, 2009
Synthesis and structure of an optically active π‐stacked poly(dibenzofulvene) bearing chiral terminal group
Authors: Nakano Tamaki , Tanikawa Mitsuru , Nakagawa Osamu , Yade Tohru , Sakamoto Takeshi
Published: November 2008

Dibenzofulvene (DBF) affords a polymer having π‐stacked conformation by anionic, cationic, and free‐radical polymerization. In this study, DBF was polymerized anionically using potassium menthoxide as initiator to obtain optically active poly(DBF) having a chiral menthoxy group as a terminal group. The obtained polymer indicated circular dichroism (CD) absorption bands in the absorption wavelength range of fluorenyl group, indicating that chiral conformation was induced to the stacked main chain by the influence of the terminal group. The CD intensity was reversibly affected by temperature of measurement; hence, the chiral conformation may be rather dynamic. The effect of the terminal group was found to decrease as the chain length increased. Theoretical CD calculation indicated that the obtained polymer has a left‐handed helical conformation and that the dihedral angle between neighboring monomeric units might be about 10–20°. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 239–246, 2009
Copolymerization of ethylene with linear α‐olefins by 2‐phosphinophenolate nickel catalysts
Authors: Guo Cun‐Yue , Peulecke Normen , Kindermann Markus K. , Heinicke Joachim W.
Published: November 2008

2‐Dicyclohexyl‐ and 2‐diphenylphosphinophenol, CCHH and PPHH, react with Ni(1,5‐COD)2 to form catalysts for polymerization of ethylene in or copolymerization with α‐olefins. The more P‐basic CCHH/Ni catalyst allows concentration‐dependent incorporation of olefins to give copolymers with isolated side groups and higher molecular weights, whereas the PPHH/Ni catalyst undergoes mainly stabilizing interactions with the olefins and leads to ethylene oligomers with no or marginal olefin incorporation. Pressure–time plots of the batch reactions show that the ethylene conversion is usually slower by catalysis with CCHH/Ni than by PPHH/Ni. The microstructure of the copolymers was determined by 13C NMR spectra, the number of side groups per main chain was estimated by 1H NMR analyses. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 258–266, 2009
Surface engineering of styrene/PEGylated‐fluoroalkyl styrene block copolymer thin films
Authors: Martinelli Elisa , Menghetti Sara , Galli Giancarlo , Glisenti Antonella , Krishnan Sitaraman , Paik Marvin Y. , Ober Christopher K. , Smilgies Detlef‐M. , Fischer Daniel A.
Published: November 2008

A series of diblock copolymers prepared from styrenic monomers was synthesized using atom transfer radical polymerization. One block was derived from styrene, whereas the second block was prepared from a styrene modified with an amphiphilic PEGylated‐fluoroalkyl side chain. The surface properties of the resulting polymer films were carefully characterized using dynamic contact angle, XPS, and NEXAFS measurements. The polymer morphology was investigated using atomic force microscope and GISAXS studies. The block copolymers possess surfaces dominated by the fluorinated unit in the dry state and a distinct phase separated microstructure in the thin film. The microstructure of these polymers is strongly influenced by the thin film structure in which it is investigated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 267–284, 2009
Poly(triphenylamine)s derived from oxidative coupling reaction: Substituent effects on the polymerization, electrochemical, and electro‐optical properties
Authors: Lin Hung‐yi , Liou Guey‐Sheng
Published: November 2008

A series of triphenylamine‐based polymers containing electron‐donating methoxy (OCH3) and electron‐withdrawing cyano or nitro (CN or NO2) substituents in the main chains have been designed and investigated. These conjugated polymers (P1–P3) could be readily prepared by oxidative coupling polymerization from monomers (M1–M3) using FeCl3 as an oxidant. The P2 and P3 exhibited moderate high Tg values (203–205 °C) and thermal stability. These polymers in NMP solution showed UV–vis absorption around 288–404 nm and photoluminescence peaks around 435–492 nm. P1–P3 showed reversible oxidation redox couples at Eonset = 0.67, 0.99, and 1.00 V in solution of 0.1 M tetrabutylammonium perchlorate (TBAP)/acetonitrile (CH3CN), respectively. M3 and P3 exhibited reversible reduction redox couples at Eonset = −1.04 and −1.03 V. These polymers also revealed electrochromic characteristic changing color at different potential. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 285–294, 2009
Surface characterization and electrical behavior of polyaniline–polymannuronate nanocomposites
Authors: Basavaraja C. , Veeranagouda Y. , Lee Kyoung , Pierson R. , Huh Do Sung
Published: November 2008

Conducting polyaniline‐polymannuronate (PANI‐PM) composites were synthesized via in situ deposition techniques. By dissolving different weight percentages of polymannuronate (PM) (5, 10, 15, and 25%), the oxidative polymerization of aniline was achieved through the use of ammonium persulfate as oxidant. Structural morphology, FT‐IR, and X‐ray diffraction (XRD) studies support a strong interaction between PANI and PM. The temperature‐dependent DC conductivity of PANI‐PM composites was studied within the range of 300 ≤ T ≤ 500 °K, presenting evidence for the transport properties of PANI‐PM composites. Conductivity was analyzed through Mott's equation, which leveraged the variable range hopping model in three dimensions. Parameters such as density of states at the Fermi energy, hopping energy, and hopping distance were calculated. Based on the above factors, the synthesis of PANI‐PM composites envisages the future development of biomimetic materials for the creation of a new bionanocomposite as a multicomponent and multifunctional material. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 36–45, 2009
Vibrational spectroscopy analysis of ion conduction mechanism in dispersed phase polymer nanocomposites
Authors: Mohapatra Saumya R. , Thakur Awalendra K. , Choudhary R. N. P.
Published: November 2008

A novel combination of dispersed phase polymer nanocomposite electrolyte based on PEO8‐LiClO4+ x wt % nano‐CeO2 has been investigated. A model for ion transport mechanism has been proposed to account for substantial enhancement of its electrical conductivity by ∼ 2 orders of magnitude at low volume fraction of the filler reinforcement in the polymer nanocomposite films. The strength of the proposed model is based on unambiguous evidences from FTIR, TEM, and conductivity analysis. The FTIR results provide clear role of nanofiller concentration on ion–ion interaction quantified in terms of the fraction of free anion and ion‐pairs present in the nanocomposite films and its excellent correlation with conductivity versus filler concentration. The presence of asymmetry in the ν4(ClO4−) band observed at 625 cm−1 is attributed to its resolved degeneracy suggesting the presence of both uncoordinated and cation‐coordinated ClO4− anion in the matrix due to ion–ion and ion–filler interactions assisted by Lewis acid–base interaction. The enhancement in conductivity at low concentration is possibly due to direct interaction of nano‐CeO2 with both polymer host and anions resulting in the release of ionic charges. Drastic conductivity reduction at higher concentration is related to charge immobilization because of ion/ion‐pair entrapment by local clusters of filler as evidenced in TEM. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 60–71, 2009
The effects of monoepoxide chain termination and their derived soluble fractions on the structure‐property relationships of controlled epoxy networks
Authors: Marks Maurice J. , Verghese Nikhil E. , O'Connell Carol L. , Mansour Ameara S.
Published: November 2008

A new series of monoepoxide terminated controlled epoxy networks (CENs) and a corresponding soluble fraction polymer (SFP) were prepared to further investigate the effects of chain termination on epoxy thermoset structure‐property relationships. CENs having an initial molecular weight between crosslinks (Mc,i) of ∼3000 g/mol using phenylglycidyl ether (PGE) as the chain terminator have thermal and mechanical properties consistent with previously studied monophenol terminated CENs. Glass transition temperature (Tg) decreases monotonically with PGE concentration (ε), whereas fracture toughness decreases sharply at a critical PGE concentration (εc). A PGE terminated SFP was prepared corresponding to the soluble fraction expected for the CEN composition at εc. The SFP behaves as a weak antiplasticizer in these epoxy thermosets;Tgis reduced and follows the inverse rule of mixtures, and fracture toughness is slightly reduced. By difference it is inferred that most of the deterioration of epoxy thermoset properties resulting from incorporation of chain terminators above εcis a result of the presence of nonelastically active pendant chains and by the increase inMc. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 72–79, 2009
Glass transition temperatures in binary polymer blends
Authors: Kalogeras Ioannis M. , Brostow Witold
Published: November 2008

Knowledge of the glass transition temperatures (Tgs) as function of composition reflects miscibility (or lack of it) and is decisive for virtually all properties of polymer‐based materials. In this article, we analyze single blend‐average and effective Tgs of miscible polymer blends in full concentration ranges. Shortcomings of the extant equations are discussed to support the need for an alternative. Focusing on the deviation from a linear relationship, defined as ΔTg = Tg − φ1Tg,1 − φ2Tg,2 (where φi and Tg,i are, respectively, the weight fraction and the Tg of the i‐th component), a recently proposed equation for the blend Tg as a function of composition is tested extensively. This equation is simple; a quadratic polynomial centered around 2φ1 − 1 = 0 is defined to represent deviations from linearity, and up to three parameters are used. The number of parameters needed to describe the experimental data, along with their magnitude and sign, provide a measure of the system complexity. For most binary polymer systems tested, the results obtained with the new equation are better than those attained from existing Tg equations. The key parameter of the equation a0 is related to parameters commonly used to represent intersegmental interactions and miscibility in binary polymer blends. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 80–95, 2008
Molecular mobility of nitroxide spin probes in glassy polymers. Quasi‐libration model
Authors: Chernova Daria A. , Vorobiev Andrey KH.
Published: November 2008

ESR spectra of three spin probes with different molecular volumes: 2,2,6,6‐tetramethyl‐4‐oxopiperidine‐1‐oxyl, di‐p‐anisylnitroxide, and nitroxide derivative of fullerene in glassy polystyrene, polyvinyl trimethylsilane, and Teflon AF‐2400 were calculated numerically within the model of quasi‐libration motions. Temperature ranges, where the model is capable to reproduce spectra within experimental errors, were defined. It was found that simulation of X‐band ESR spectra allows to determine quasi‐libration amplitudes around molecular axes X and Y with accuracy ∼ 3° and around Z axis with accuracy ∼ 15–20°. A shape of distribution of quasi‐libration amplitudes was also determined qualitatively by ESR spectra simulations. It was established that the average amplitude of quasi‐libration motion depends on the free volume of each polymer and geometrical molecular volume of a spin probe. Quasi‐libration amplitudes increase as the temperature increases, and reach the value of 40 degrees. We found that upon further temperature increase, quasi‐libration model becomes inapplicable for quantitative numerical spectra simulation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 107–120, 2009
Predictors of treatment decision evaluation in patients with cancer
Authors: Erci Behice , Özdemir Süreyya
Published: November 2008

Objective: The purpose of this study was to examine the predictors of treatment decision evaluation in patients with cancer.

Methods: A convenience sample of 199 patients with cancer at a Turkish university hospital completed a structured questionnaire including demographic characteristics and the treatment decision evaluation for patients with cancer in 2006. In analysis of the data, descriptive statistics, and multiple regression analysis were used.

Results: The mean scores of the treatment decision evaluation's subscales showed that the patient were uncertain about their satisfaction with the treatment decision. The mean score of the symptom inventory suggested that the patients had moderate‐level symptoms. Education level, marital status, and the severity symptoms of the independent variables were effective predictors of the treatment decision evaluation. Together the independent variables explained 18.7% of the variance of the satisfaction–uncertainty dimension, 9.1% of the variance of the informed choice dimension, and 16% of the variance of the decision control dimension. Overall the independent variables explained 8.3% of the variance of the treatment decision evaluation.

Conclusions: The results in this study should increase the awareness of cancer care professionals about a range of treatment decision evaluation and may help them to target particular patient groups for particular support interventions and informed treatment decision. Copyright © 2008 John Wiley & Sons, Ltd.
Gene expression profiles of lysophosphatidic acid‐related molecules in the prostate: Relevance to prostate cancer and benign hyperplasia
Authors: Zeng Yu , Kakehi Yoshiyuki , Nouh Mohammed Ahmed Abdel Muneem , Tsunemori Hiroyuki , Sugimoto Mikio , Wu Xiu‐Xian
Published: November 2008

OBJECTIVE

To elucidate gene expression profiles of lysophosphatidic acid (LPA)‐related molecules in cancer, pre‐cancerous lesion, and benign hyperplasia of the prostate.

MATERIALS AND METHODS

Prostate tissue samples were surgically obtained from 10 patients with localized prostate cancer and seven patients with invasive bladder cancer. Cancer cells and the corresponding stromal cells from normal prostate, high grade intraepithelial neoplasia (HGPIN), benign hyperplastic glands were isolated by laser capture microdissection. mRNA levels of three LPA receptors, LPA1, LPA2, LPA3, two LPA‐synthesizing enzymes, autotaxin (ATX), acylglycerol kinase (AGK), and a LPA‐degradation enzyme, prostatic acid phosphatase (PAP), were quantitatively assessed. The expression levels of the same genes were also determined in three human prostate cancer cell lines LNCaP, PC‐3, and DU‐145.

RESULTS

LPA1 mRNA level was significantly decreased in HGPIN and cancer epithelia when compared to the benign glands. LPA3 mRNA level was elevated in cancer epithelia compared to benign glands. LPA3, AGK, and PAP were predominantly expressed in LNCaP cells while LPA1 and ATX gene expressions were found in PC‐3 and Du‐145 cells. In BPH, AGK was abundantly expressed in the stroma while PAP was predominant in epithelial cells.

CONCLUSIONS

By acting via LPA3, LPA may play an important role in the development of prostate cancer. Switching of LPA receptor expression from LPA3 to LPA1, may be involved in prostate cancer progression and/or androgen independence. LPA may also play a key role in the development of benign prostatic hyperplasia. Prostate 69:283–292, 2009. © 2008 Wiley‐Liss, Inc.
Conformational preferences of a short Aib/Ala‐based water‐soluble peptide as a function of temperature
Authors: Banerjee Raja , Chattopadhyay Sarbani , Basu Gautam
Published: November 2008

The amino acid Aib predisposes a peptide to be helical with context‐dependent preference for either 310‐ or α‐ or a mixed helical conformation. Short peptides also show an inherent tendency to be unfolded. To characterize helical and unfolded states adopted by water‐soluble Aib‐containing peptides, the conformational preference of Ac‐Ala‐Aib‐Ala‐Lys‐Ala‐Aib‐Lys‐Ala‐Lys‐Ala‐Aib‐Tyr‐NH2was determined by CD, NMR and MD simulations as a function of temperature. Temperature‐dependent CD data indicated the contribution of two major components, each an admixture of helical and extended/polyproline II structures. Both right‐ and left‐handed helical conformations were detected from deconvolution of CD data and13C NMR experiments. The presence of a helical backbone, more pronounced at the N‐terminal, and a temperature‐induced shift in α‐helix/310‐helix equilibrium, more pronounced at the C‐terminal, emerged from NMR data. Starting from polyproline II, the N‐terminal of the peptide folded into a helical backbone in MD simulations within 5 ns at 60°C. Longer simulations showed a mixed‐helical backbone to be stable over the entire peptide at 5°C while at 60°C the mixed‐helix was either stable at the N‐terminus or occurred in short stretches through out the peptide, along with a significant population of polyproline II. Our results point towards conformational heterogeneity of water‐soluble Aib‐based peptide helices and the associated subtleties. The problem of analyzing CD and NMR data of both left‐ and right‐handed helices are discussed, especially the validity of the ellipticity ratio [θ]222/[θ]207, as a reporter of α‐/310‐ population ratio, in right‐ and left‐handed helical mixtures. Proteins 2009. © 2008 Wiley‐Liss, Inc.
A review of forecast error covariance statistics in atmospheric variational data assimilation. I: Characteristics and measurements of forecast error covariances
Authors: Bannister R. N.
Published: November 2008

This article reviews the characteristics of forecast error statistics in meteorological data assimilation from the substantial literature on this subject. It is shown how forecast error statistics appear in the data assimilation problem through the background error covariance matrix, B. The mathematical and physical properties of the covariances are surveyed in relation to a number of leading systems that are in use for operational weather forecasting. Different studies emphasize different aspects of B, and the known ways that B can impact the assimilation are brought together. Treating B practically in data assimilation is problematic. One such problem is in the numerical measurement of B, and five calibration methods are reviewed, including analysis of innovations, analysis of forecast differences and ensemble methods. Another problem is the prohibitive size of B. This needs special treatment in data assimilation, and is covered in a companion article (Part II). Examples are drawn from the literature that show the univariate and multivariate structure of the B‐matrix, in terms of variances and correlations, which are interpreted in terms of the properties of the atmosphere. The need for an accurate quantification of forecast error statistics is emphasized. Copyright © 2008 Royal Meteorological Society
A review of forecast error covariance statistics in atmospheric variational data assimilation. II: Modelling the forecast error covariance statistics
Authors: Bannister R. N.
Published: November 2008

This article reviews a range of leading methods to model the background error covariance matrix (the B‐matrix) in modern variational data assimilation systems. Owing partly to its very large rank, the B‐matrix is impossible to use in an explicit fashion in an operational setting and so methods have been sought to model its important properties in a practical way. Because the B‐matrix is such an important component of a data assimilation system, a large effort has been made in recent years to improve its formulation. Operational variational assimilation systems use a form of control variable transform to model B. This transform relates variables that exist in the assimilation's ‘control space’ to variables in the forecast model's physical space. The mathematical basis on which the control variable transform allows the B‐matrix to be modelled is reviewed from first principles, and examples of existing transforms are brought together from the literature. The method allows a large rank matrix to be represented by a relatively small number of parameters, and it is shown how information that is not provided explicitly is filled in. Methods use dynamical properties of the atmosphere (e.g. balance relationships) and make assumptions about the way that background errors are spatially correlated (e.g. homogeneity and isotropy in the horizontal). It is also common to assume that the B‐matrix is static. The way that these, and other, assumptions are built into systems is shown.

The article gives an example of how a current method performs. An important part of this article is a discussion of some new ideas that have been proposed to improve the method. Examples include how a more appropriate use of balance relations can be made, how errors in the moist variables can be treated and how assumptions of homogeneity/isotropy and the otherwise static property of the B‐matrix can be relaxed. Key developments in the application of dynamics, wavelets, recursive filters and flow‐dependent methods are reviewed. The article ends with a round up of the methods and a discussion of future challenges that the field will need to address. Copyright © 2008 Royal Meteorological Society
The detection of androstenedione abuse in sport: a mass spectrometry strategy to identify the 4‐hydroxyandrostenedione metabolite
Authors: Cawley Adam T. , Trout Graham J. , Kazlauskas Rymantas , George Adrian V.
Published: November 2008

Studies have shown that the administration of androstenedione (ADIONE) significantly increases the urinary ratio of testosterone glucuronide to epitestosterone glucuronide (T/E) – measured by gas chromatography/mass spectrometry (GC/MS) – in subjects with a normal (≈1) or naturally high (>1) initial values. However, the urinary T/E ratio has been shown not to increase in subjects with naturally low (<1) initial values. Such cases then rely on the detection of C6‐hydroxylated metabolites shown to be indicative of ADIONE administration. While these markers may be measured in the routine GC/MS steroid profile, their relatively low urinary excretion limits the use of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) to specifically confirm ADIONE administration based on depleted 13C content. A mass spectrometry strategy was used in this study to identify metabolites of ADIONE with the potential to provide compound‐specific detection. C4‐hydroxylation was subsequently shown to be a major metabolic pathway following ADIONE administration, thereby resulting in urinary excretion of 4‐hydroxyandrostenedione (4OH‐ADIONE). Complementary analysis of 4OH‐ADIONE by GC/MS and GC/C/IRMS was used to confirm ADIONE administration. Copyright © 2008 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.
Gas chromatography/tandem mass spectrometry analysis of alkylresorcinols in red blood cells
Authors: Nagy Kornél , Ross Alastair B. , Fay Laurent B. , Bourgeois Alexandre , Kussmann Martin
Published: November 2008

Erythrocyte alkylresorcinols (5‐alkyl‐1,3‐dihydroxybenzenes) are potential biomarkers of wholegrain wheat and rye intake. However, their high‐throughput quantitative analysis by gas chromatography/mass spectrometry (GC/MS) is hindered by the time‐consuming sample preparation and, more importantly, by interfering compounds that still remain after sample cleanup. In the present work we describe a gas chromatography/tandem mass spectrometry (GC/MS/MS) method for the rapid and reliable quantification of alkylresorcinols in erythrocyte samples. The performance of the GC/MS/MS method is compared with that of GC/MS. The main characteristics of the method are: lower limits of detection: 2–10 µg/L standard solution; lower limits of quantification: 6–30 µg/L standard solution; linearity coefficients: 0.9611–0.9888; linear ranges: 2–20 µg/L in erythrocytes; and intra‐day precisions (n = 6): 4–13% at endogenous analyte levels in non‐spiked erythrocytes. Tandem mass spectrometry showed greatly improved selectivity over single‐stage mass spectrometry in the case of erythrocyte samples, eliminating all interferences detectable in single‐stage MS and enabling simple peak integration for quantification. Moreover, increased selectivity resulted in GC separation speeded up by a factor of two, allowing the duplicate analysis of over 40 samples per day. This GC/MS/MS method is suggested as an improved alternative to GC/MS for the quantification of alkylresorcinols in erythrocytes for assessing wholegrain wheat and rye intake. Copyright © 2008 John Wiley & Sons, Ltd.
Gas‐phase behavior of noncovalent transmembrane segment complexes
Authors: Weigang Linda M. M. , Langosch Dieter , Letzel Thomas
Published: November 2008

Specific helix oligomerization between transmembrane segments (TMSs) is often promoted by motifs like GxxxG. Disruption of this motif in the transmembrane segments of vesicular stomatitis virus G‐protein and of glycophorin A results in a reduced dimerization level studied by in vivo systems like ToxR. This paper reports the influence of sequence motifs like GxxxG in solution and the gas phase.

The transmembrane segments may behave differently in the gas and liquid phase, because of the absence of surrounding solvent molecules in the gas phase. Comparison of experiments depending on peptide properties performed in the gas and liquid phase discloses that the peptides retain ‘some memory’ of their liquid‐phase structure in the gas phase. A direct correlation has been found between helicity in solution as determined by circular dichroism and dimerization in the gas phase monitored by electrospray mass spectrometry. These results show that a proper folding in solution is required for oligomerization.

On the other hand, sequence‐specific oligomerization depending on the GxxxG motif was not observed with the mass spectrometric detection. Further on, neither concentration‐dependent complex studies nor studies regarding complex stability in the gas phase – via collision‐induced dissociation (CID) – led to sequence‐specific differences.

Finally, the findings show that in mass spectrometric measurements noncovalent interactions of studied TMSs is rather more dependent on the secondary structure and proper folding than on their primary structure. Copyright © 2008 John Wiley & Sons, Ltd.
Change‐point alterations of extreme water levels and underlying causes in the Pearl River Delta, China
Authors: Chen Yongqin David , Zhang Qiang , Xu Chong‐Yu , Yang Tao , Chen Xiaohong , Jiang Tao
Published: November 2008

In this paper, the Bayesian model and Lepage test were used to detect change point and to analyse associated statistical properties of high/low water levels in summer (June, July and August (JJA)) and winter (December, January and February (DJF)) months across the PRD (Pearl River Delta). The results indicate that: (1) two time intervals, that is 1979–1981 and 1988–1995, witness abrupt changes of SmH/SmL (summer mean high water level/summer mean low water level). The lower PRD is dominated by increased mean and coefficient of variation (Cv) of SmH. Increased mean but decreased Cv of SmL can be observed in the Mainstem Pearl River; (2) WmL (winter mean low water level) and WmH (winter mean high water level) of about 74% of the total stations have two change points occurred roughly during 1969–1971 and 1993–1995. First change points of WmH are mainly characterized by increased mean and Cv, but decreased mean and increased Cv of WmL can be observed across major parts of the PRD. The driving factors causing abrupt changes of water levels are various. Intensive human activities cannot be ignored, for example in‐channel dredging and reallocation of the streamflow within the river channels due to human‐induced topographical changes of river channel. Different responses of high/low water levels to externally influencing factors and interactions between influencing factors make the alterations of the water levels across the PRD more complicated. The findings of this paper will be helpful for the management of the PRD and human mitigation to natural hazards under the changing environment. Copyright © 2008 John Wiley & Sons, Ltd.
Contribution of urban design to economic sustainability of urban renewal projects in Hong Kong
Authors: Chan Edwin H. W. , Lee Grace K. L.
Published: November 2008

Urban renewal in Hong Kong plays an important role in stimulating local economy by optimizing development potential of disturbed site and introducing new activities/businesses with large profit margins. However, past and current urban renewal practices put too much emphasis on achieving economic objectives, and overlook the environmental and social needs of the community, which violates the global trend to promote sustainable development in the urban areas. In view of it, this paper has reviewed the property‐led/ market‐led urban renewal approach continuously adopted in Hong Kong, and suggested a more sustainable approach to meet economic objectives. In order to facilitate such approach, this paper has highlighted a list of urban design considerations contributing to sustainable development and identified key design factors improving economic sustainability of the urban renewal projects. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment.
Multiple imputation to correct for partial verification bias revisited (5880–5889)
Authors: de Groot J. A. H. , Janssen K. J. M. , Zwinderman A. H. , Moons K. G. M. , Reitsma J. B.
Published: November 2008

Statist. Med. DOI: 10.1002/sim.3410. Published Online: 27th August 2008 10:34AM.

The Editors regret that the print publication of this paper, which was published on Early View on 27th August 2008, has occurred after the publication of a submitted Correction (Statistics in Medicine 2008; 27:4614) to the paper by Harel and Zhou [3].

The lack of reference in this Correction to previous correspondence [4,5] and to this paper by de Groot, Janssen, Zwinderman, Moons and Reitsma is particularly unfortunate and we apologize to our readers and to de Groot, Janssen, Zwinderman, Moons and Reitsma.
Student interest generated during an inquiry skills lesson
Authors: Palmer David H.
Published: November 2008

“Situational interest” is a short‐term form of motivation which occurs when a specific situation stimulates the focused attention of students (e.g., a spectacular science demonstration could arouse transient interest amongst nearly all the students in a class, even those who are not normally interested in science). However, there have been very few studies of situational interest and its potential to motivate students in science classrooms. The purpose of this project was to investigate situational interest and its sources. Small groups of grade 9 students participated in a science lesson which focused on inquiry skills, and data were obtained on their interest levels and sources of interest. The results indicated that interest arousal was substantial but did fluctuate throughout the lesson, according to the types of activities in which students were involved. The main source of interest was novelty, although choice, physical activity, and social involvement were also implicated. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 46: 147–165, 2009
Written extended‐response questions as classroom assessment tools for meaningful understanding of evolutionary theory
Authors: Nieswandt Martina , Bellomo Katherine
Published: November 2008

This qualitative study analyzed grade 12 biology students' answers to written extended‐response questions that describe hypothetical scenarios of animals' evolution. We investigated whether these type of questions are suitable for students (n = 24) to express a meaningful understanding of evolutionary theory. Meaningful understanding is comprised of factual, procedural (rules, algorithms), schematic (“knowing why”), and strategic knowledge (when, where and how to apply knowledge). Evolutionary theory as a multi‐level concept includes concepts on three different levels (descriptive, hypothetical, and theoretical). Students' answers are examined as to whether they reflect the meaningful linking of all concepts through appropriate use of scientific language. Results showed that students (a) predominantly linked descriptive concepts and, although expected, (b) demonstrated only some cross‐concept‐level links (theoretical–descriptive), (c) exhibited even fewer multi‐concept‐level links (theoretical–descriptive–hypothetical), and (d) avoided the linking of hypothetical concepts with theoretical ones. All these results showed the lack of explanations and reasoning (absence of schematic and strategic knowledge) and knowledge of how to link concepts about evolutionary theory meaningfully. The results indicate further that written extended‐response questions are only partially suitable for demonstrating meaningful understanding. Implications for teaching of evolutionary theory are discussed. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 46: 333–356, 2009
Influences on visitor behavior at a modern immersive zoo exhibit
Authors: Ross Stephen R. , Gillespie Katie L.
Published: November 2008

Zoos serve as centers for both research and education. The challenge is to convey messages about their conservation projects while meeting visitor expectations, which often include recreation and entertainment. One way this can be achieved is through the design of immersive exhibits that draw visitors in and engage them with interactive educational elements. Regenstein African Journey (RAJ) opened at Lincoln Park Zoo in 2003 and was designed to take visitors on a simulated safari through Africa. Because visitor experience was a major design goal, we conducted a timing and tracking study to evaluate use of the building and educational components. For a 9‐week period in 2003, we tracked 338 visitors to RAJ and recorded continuous data as they moved through the building. Data were collected on handheld computers that provided precise timing data. The median visit was 11.08 min, 41% of which was spent looking at animals and 9% of which was spent engaged with interpretive elements. We found significant differences in the way visitors used signage: those in groups without children spent more of their visit engaged with signage than those with children and visitors who spent more of their visit interacting socially spent less time engaged with signage. By understanding how visitors use the educational opportunities presented to them, we can better meet their expectations and more effectively achieve the goal of conservation education. Zoo Biol 28:462–472, 2009. © 2008 Wiley‐Liss, Inc.
Frequency and seriousness of parental offending and their impact on juvenile offending
Authors: Nijhof Karin S. , de Kemp Raymond A.T. , Engels Rutger C.M.E.
Published: November 2008

The present study investigated to what extent the frequency and seriousness of parental offending were related to their offspring offending. Police officers in one Dutch province completed a form to register risk factors and the actions undertaken when they came into contact with offenders aged 8–14 years. These juveniles were followed for 18 months to establish whether or not they committed more crimes. In addition, the parents of these children were traced in the police criminal record systems. Data were gathered from 577 children and their parents. Of these children, 34% were exposed to parental criminality, of which 33 delinquents had two criminal parents and 163 had one criminal parent. If both parents were criminal, the child had the highest frequency of offending. Further, the frequency of parental offending was positively related to the frequency of the child's offending. Concerning the seriousness of juvenile crimes, the seriousness of the committed offences of the father showed a positive relation with the seriousness of his child's offending. Unexpectedly, a negative association was found between the seriousness of maternal offending and the seriousness of her child offending. These results offered a better understanding of the influence that parents with a criminal history have on their children. Further research is needed to identify mechanisms underlying this relationship in order to provide appropriate prevention and intervention strategies.
Symptoms of problematic cellular phone use, functional impairment and its association with depression among adolescents in Southern Taiwan
Authors: Yen Cheng‐Fang , Tang Tze‐Chun , Yen Ju‐Yu , Lin Huang‐Chi , Huang Chi‐Fen , Liu Shu‐Chun , Ko Chih‐Hung
Published: November 2008

The aims of this study were: (1) to examine the prevalence of symptoms of problematic cellular phone use (CPU); (2) to examine the associations between the symptoms of problematic CPU, functional impairment caused by CPU and the characteristics of CPU; (3) to establish the optimal cut‐off point of the number of symptoms for functional impairment caused by CPU; and (4) to examine the association between problematic CPU and depression in adolescents. A total of 10,191 adolescent students in Southern Taiwan were recruited into this study. Participants' self‐reported symptoms of problematic CPU and functional impairments caused by CPU were collected. The associations of symptoms of problematic CPU with functional impairments and with the characteristics of CPU were examined. The cut‐off point of the number of symptoms for functional impairment was also determined. The association between problematic CPU and depression was examined by logistic regression analysis. The results indicated that the symptoms of problematic CPU were prevalent in adolescents. The adolescents who had any one of the symptoms of problematic CPU were more likely to report at least one dimension of functional impairment caused by CPU, called more on cellular phones, sent more text messages, or spent more time and higher fees on CPU. Having four or more symptoms of problematic CPU had the highest potential to differentiate between the adolescents with and without functional impairment caused by CPU. Adolescents who had significant depression were more likely to have four or more symptoms of problematic CPU. The results of this study may provide a basis for detecting symptoms of problematic CPU in adolescents.
Deliberate self‐harm in adolescents: Comparison between those who receive help following self‐harm and those who do not
Authors: Ystgaard Mette , Arensman Ella , Hawton Keith , Madge Nicola , van Heeringen Kees , Hewitt Anthea , Jan de Wilde Erik , De Leo Diego , Fekete Sandor
Published: November 2008

This international comparative study addresses differences between adolescents who engage in deliberate self‐harm (DSH) and who receive help following the DSH episode versus those who do not. A standardised self‐report questionnaire was completed by pupils aged 14–17 in Australia, Belgium, England, Hungary, Ireland, The Netherlands, and Norway (n = 30 532). An act of DSH in the year prior to the study was reported by 1660 participants. Nearly half (48.4%) had not received any help following DSH, 32.8% had received help from their social network only and 18.8% from health services. Except for Hungary, cross‐national comparisons revealed remarkably similar findings. Adolescents who had been in contact with health services following DSH reported more often a wish to die, lethal methods, alcohol/drug problems and DSH in the family compared to those who had not. However, those who received no help or help from their social network only were also heavily burdened.
Different types of Internet use, depression, and social anxiety: The role of perceived friendship quality
Authors: Selfhout Maarten H.W. , Branje Susan J.T. , Delsing M. , ter Bogt Tom F.M. , Meeus Wim H.J.
Published: November 2008

The current study examined the longitudinal associations of time spent on Internet activities for communication purposes (i.e., IM‐ing) versus time spent on Internet activities for non‐communication purposes (i.e., surfing) with depression and social anxiety, as well as the moderating role of perceived friendship quality in these associations. Questionnaire data were gathered from 307 Dutch middle adolescents (average age 15 years) on two waves with a one‐year interval. For adolescents who perceive low friendship quality, Internet use for communication purposes predicted less depression, whereas Internet use for non‐communication purposes predicted more depression and more social anxiety. These results support social compensation effects of IM‐ing on depression and poor‐get‐poorer effects of surfing on depression and social anxiety, respectively.
Emotional numbing and pain intensity predict the development of pain disability up to one year after lateral thoracotomy
Authors: Katz Joel , Asmundson Gordon J.G. , McRae Karen , Halket Eileen
Published: November 2008

Little is known about the factors that predict the transition of acute, time limited pain to chronic pathological pain following postero‐lateral thoracotomy. The aim of the present prospective, longitudinal study was to determine the extent to which (1) pre‐operative pain intensity, pain disability, and post‐traumatic stress symptoms (PTSS) predict post‐thoracotomy pain disability 6 and 12 months later; and (2) if these variables, assessed at 6 months, predict 12 month pain disability. Fifty‐four patients scheduled to undergo postero‐lateral thoracotomy for intrathoracic malignancies were recruited before surgery and followed prospectively for one year. The incidence of chronic post‐thoracotomy pain was 68.1% and 61.1% at the 6 and 12 month follow‐ups, respectively. Multiple regression analyses showed that neither pre‐operative factors nor acute movement‐evoked post‐operative pain predicted 6 or 12 month pain disability. However, concurrent pain intensity and emotional numbing, but not avoidance symptoms, made unique, significant contributions to the explanation of pain disability at each follow‐up (total R2=76.3.0% and 63.9% at 6 and 12 months, respectively, both p<0.0009). The relative contribution of pain intensity decreased, while that of emotional numbing increased with time, indicating a progressive de‐coupling of pain intensity and disability and a concomitant strengthening of the link between emotional numbing and disability. This suggests that pain may serve as a traumatic stressor which causes increased emotional numbing. The results also support recent suggestions that avoidance and emotional numbing constitute separate PTSS clusters. Further research is required to determine the source(s) of emotional numbing after postero‐lateral thoracotomy and effective interventions.