bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitation of alcohol ethoxylate surfactants in environmental samples by electrospray mass spectrometry
Authors: Evans K. A. , Dubey S. T. , Kravetz L. , Evetts S. W. , Dzidic I. , Dooyema C. C.
Published: June 2007

This report describes a method for obtaining the concentrations of the total and individual alcohol ethoxylate (AE) species in sewage treatment plant (STP) effluents by using electrospray liquid chromatography/mass spectrometry (LC/MS). This is a more advantageous method for quantitative analysis of AE in environmental matrices as compared with a previous thermospray LC/MS method. This new method is more sensitive, uses less solvents, utilizes a deuterated internal standard blend [C13D27O(CH2CH2O)nH, where n varies from 0 to 21 with an average of n=9], which corresponds more closely to the AE, and it is a more robust instrumental technique. In this report, we document the results for validation of the electrospray LC/MS method by spike recovery of AE from STP effluent and influent samples.
Conductometric investigations of zirconyl soaps in a xylene‐methanol mixture
Authors: Mehrotra K. N. , Anis M.
Published: June 2007

Conductometric measurements of solutions of zirconyl soaps in xylene‐methanol (4:1, vol/vol) mixture were carried out at 30–50°C, and the results were used to determine the degree of ionization, ionization constant, and various thermodynamic parameters for both ionization and association processes. The results show that the soaps behave as weak electrolytes in dilute solutions, and the concentrations at which aggregation commences increased with increasing temperature and decreasing chainlength of the soap molecules.
New oxidation pathway of 3,5‐di‐tert‐butyl‐4‐hydroxytoluene: An ionspray tandem mass spectrometric and gas chromatographic/mass spectrometric study
Authors: Zhang Nan , Kawakami Shoji , Higaki Masato , Wee Victorio T.
Published: June 2007

The autoxidation of 3,5‐di‐tert‐butyl‐4‐hydroxytoluene (BHT, 1) in bar soap was investigated with ionspray tandem mass spectrometric and on‐line gas chromatographic/mass spectrometric methods. The oxidation products of BHT were extracted from the bar soap surface, concentrated, and fractionated with open‐column chromatography to remove the impurities. New oxidation products of BHT (BHT phenol‐type dimer 7 and others) were identified with the two mass spectrometric methods. The results suggested that oxidation of BHT in bar soap occurred in a way different from that in the previous studies. In the new pathway, oxidation of BHT first generates an excited state of phenol‐type dimer 4, and then this species decomposes, due to its high energy, to form dimer 7. The mechanism of oxidation is discussed.
Biocatalytic synthesis of chiral intermediates for antiviral and antihypertensive drugs
Authors: Patel Ramesh N.
Published: June 2007

The chiral intermediate (1S,2R) [3‐chloro‐2‐hydroxy‐1‐(phenylmethyl)propyl] carbamic acid, 1,1‐dimethylethyl ester 2a was prepared for the total synthesis of a human immunodeficiency virus protease inhibitor, BMS‐186318. The stereoselective reduction of (1S) [3‐chloro‐2‐oxo‐1(phenylmethyl)propyl] carbamic acid, 1,1‐dimethylethyl ester 1 was carried out using microbial cultures, among which Streptomyces nodosus SC 13149 efficiently reduced 1 to 2a. A reaction yield of 80%, enantiomeric excess (e.e.) of 99.8%, and diastereomeric purity of 99% were obtained for chiral alcohol 2a. Chiral l‐6‐hydroxy norleucine 3, an intermediate in the synthesis of antihypertensive drug, was prepared by reductive amination of 2‐keto‐6‐hydroxyhexanoic acid 4 using beef liver glutamate dehydrogenase. The cofactor NADH required for this reaction was regenerated using glucose dehydrogenase from Bacillus sp. A reaction yield of 80% and e.e. of 99.5% were obtained for l‐6‐hydroxynorleucine 3. To avoid the lengthy chemical synthesis of the ketoacid, a second route was developed in which racemic 6‐hydroxynorleucine [readily available from hydrolysis of 5‐(4‐hydroxybutyl) hydantoin 5] was treated with d‐amino acid oxidase from Trigonopsis variabilis to selectively convert the d‐isomer of racemic 6‐hydroxynorleucine to 2‐keto‐6‐hydroxyhexanoic acid 4 and l‐6‐hydroxynorleucine 3. Subsequently, the 2‐keto‐6‐hydroxyhexanoic acid 4 was converted to l‐6‐hydroxynorleucine by reductive amination using glutamate dehydrogenase. A reaction yield of 98% and an e.e. of 99.5% were obtained.
Determination of (+)‐, (−)‐, and total gossypol in cottonseed by high‐performance liquid chromatography
Authors: Hron R. J. , Kim H. L. , Calhoun M. C. , Fisher G. S.
Published: June 2007

Gossypol, a pigment in cottonseed, is a polyphenolic, binaphthyl dialdehyde. Due to steric hindrance between the functional groups of the molecule at the bond connecting the two naphthyl rings, gossypol exists as (+)‐ and (−)‐isomers. Gossypol is physiologically active with the (−)‐isomer appearing to be more active and causing temporary infertility in males. It is thus important to know the amounts of isomers in livestock feeds. A quantitative high‐performance liquid chromatography (HPLC) procedure was developed for the separation of (+)‐ and (−)‐gossypol contained in cottonseed. This method involves derivatization of gossypol with (R)‐(−)‐2‐amino‐1‐propanol followed by HPLC separation employing either a Phenomenex Prodigy (5 µ, ODS‐3, 100 × 3.2 mm) or a MetaChem Inertsil (5 µ, ODS‐3, 100 × 3.0 mm) reversed‐phase column eluted with 80% acetonitrile and 20% 10 mM KH2PO4 adjusted to pH 3.0 with H3PO4 at 1.0 mL/min. The (+)‐ and (−)‐gossypol‐2‐ amino‐1‐propanol complexes eluted at roughly 1.4 and 2.6 min, respectively. It was found that gossypol from Upland (Gossypium hirsutum) seed was rich in the (+)‐enantiomer, with the (+)‐ and (−)‐enantiomers in a ratio of about 65:35, respectively, while gossypol from the seed of a Pima (G. barbadense) cultivar (S‐6) was slightly richer in the (−)‐enantiomer (46.8:53.2).
Formulation of special fats by neural networks: A statistical approach
Authors: Block J. M. , Barrera‐Arellano D. , Figueiredo M. F. , Gomide F. C. , Sauer L.
Published: June 2007

In the present work, a neural network able to formulate fats with three ingredients derived from soybean (one refined oil and two hydrogenated base stocks) was built and trained. The training of the network was accomplished with data on the solid fat content (SFC) of 112 products, association with the proportions of the raw material used in their formulation. After the training, the network furnished, from the requested solid profiles, the possible formulations for the desired product. According to the statistical analysis applied to the results obtained, larger mean errors were observed in products with very low SFC and the smallest errors were found in products with high SFC. Regarding different temperatures, the network performance was more accurate for 10, 20, and 25°C than for 30, 35, and 37.5°C, where the lower measurements resulted in larger relative errors. According to evaluation by industrial experts, all the responses furnished by the network after its training were considered within the acceptable variation limits. For these experts, the network knowledge generalization (accomplished with products not presented during the training) was considered highly efficient (nearly 100%).
FTY720‐phosphate is dephosphorylated by lipid phosphate phosphatase 3
Authors: Mechtcheriakova Diana , Wlachos Alexander , Sobanov Jury , Bornancin Frederic , Zlabinger Gerhard , Baumruker Thomas , Billich Andreas
Published: June 2007

FTY720 is a novel immunomodulatory drug efficacious in the treatment of multiple sclerosis. The drug is converted in vivo to the monophosphate, FTY720‐P, by sphingosine kinase 2. This conversion is incomplete, suggesting opposing actions of kinase and phosphatase activities. To address which of the known lipid phosphatases might dephosphorylate FTY720‐P, we overexpressed the broad specificity lipid phosphatases LPP1–3, and the specific S1P phosphatases (SPP1 and 2) in HEK293 cells, and performed in vitro assays using lysates of transfected cells. Among LPPs, only LPP3 was able to dephosphorylate FTY720‐P; among SPPs, only SPP1 showed activity against FTY720‐P. On intact cells, LPP3 acted as an ecto‐phosphatase or FTY720‐P, thus representing the major phosphatase involved in the equilibrium between FTY720 and FTY720‐P observed in vivo.
γ‐Glutamyl transpeptidase GGT4 initiates vacuolar degradation of glutathione S‐conjugates in Arabidopsis
Authors: Grzam Anke , Martin Melinda N. , Hell Rüdiger , Meyer Andreas J.
Published: June 2007

The xenobiotic monochlorobimane is conjugated to glutathione in the cytosol of Arabidopsis thaliana, transported to the vacuole, and hydrolyzed to cysteine S‐bimane [Grzam, A., Tennstedt, P., Clemens, S., Hell, R. and Meyer, A.J. (2006) Vacuolar sequestration of glutathione S‐conjugates outcompetes a possible degradation of the glutathione moiety by phytochelatin synthase. FEBS Lett. 580, 6384–6390]. The work here identifies γ‐glutamyl transpeptidase 4 (At4g29210, GGT4) as the first step of vacuolar degradation of glutathione conjugates. Hydrolysis of glutathione S‐bimane is blocked in ggt4 null mutants of A. thaliana. Accumulation of glutathione S‐bimane in mutants and in wild‐type plants treated with the high affinity GGT inhibitor acivicin shows that GGT4 is required to initiate the two step hydrolysis sequence. GGT4:green fluorescent protein fusions were used to demonstrate that GGT4 is localized in the lumen of the vacuole.
Effects of Hoechst 33342 on C2C12 and PC12 cell differentiation
Authors: Adamski Danièle , Mayol Jean-François , Platet Nadine , Berger François , Hérodin Francis , Wion Didier
Published: June 2007

Accumulative evidence demonstrates that normal as well as cancer stem cells can be identified as a side population following Hoechst 33342 staining and flow cytometric analysis. This popular method is based on the ability of stem cells to efflux this fluorescent vital dye. We demonstrate that Hoechst 33342 can affect cell differentiation, suggesting potential complications in the interpretation of data.
Causative factors of taste disorders in the elderly, and therapeutic effects of zinc
Authors: Ikeda M , Ikui A , Komiyama A , Kobayashi D , Tanaka M
Published: June 2007

Objectives:

To determine the characteristics of causative factors of taste disorders amongst the elderly, and to examine the therapeutic effect of a zinc agent, taking into account age-related factors.

Subjects:

A total of 408 patients with taste disorders were divided into three groups by age: 49 years or younger, 50 to 64 years old, and 65 years or older.

Results:

The incidence of taste disorders caused by drug administration and systemic disease were significantly higher in the elderly group. A serum zinc concentration of 69 µg/dl or lower was found in 33 per cent of the elderly group, significantly more (p < 0.001) than the 19 per cent of the 49 years or younger group with such a concentration. Zinc administration was therapeutically effective in 70 per cent of the whole population studied, and in 74 per cent of the elderly population.

Conclusions:

In the elderly, the incidence of taste disorders caused by drug administration or systemic disease was significantly greater compared with other age groups. The curative effects of zinc administration were not observed to be influenced by age.
Regulatory Focus Scale (RFS): Development of a Scale to Record Dispositional Regulatory Focus
Authors: Fellner Bernhard , Holler Marianne , Kirchler Erich , Schabmann Alfred
Published: June 2007

This article presents the Regulatory Focus Scale (RFS), an instrument comprising 10 items to record promotion orientation and prevention orientation, in accordance with regulatory focus theory (Higgins, 1997, 1998). In Study 1 (n = 130), 33 newly-constructed items were specified to record dispositional regulatory focus. They were administered along with the Regulatory Strength Measure (RSM) and items of various dimensions of the Schwartz values questionnaire (Schwartz Portrait Questionnaire, SPQ). Using distribution and factor analyses (exploratory und confirmatory), 10 new items were put together to create the RFS. Promotion orientation factors were named Openness to New Things and Autonomy, whereas prevention orientation factors were termed Orientation to the Expectations of Others and Sense of Obligation. There were only low correlations between the RFS and the results of the RSM, but very clear correlations between the RFS and the SPQ. In Study 2, using an independent sample (n = 200), it was possible to confirm the factor structure of the RFS found in Study 1.
How are Temporal and Social Comparisons Related to Appraisals of Self-Rated Health During Very Old Age?
Authors: Spini Dario , Clémence Alain , Ghisletta Paolo
Published: June 2007

This study investigated the direction of effects of temporal and downward social comparisons on self-rated health in very old age. Conversely, self-rated health can either reinforce or hinder comparison processes. In the framework of the Swiss Interdisciplinary Longitudinal Study on the Oldest Old, individuals aged 80 to 84 at baseline were interviewed and followed longitudinally for 5 years. Multilevel analyses were used to test the relative importance of temporal and social comparisons on self-rated health evaluations synchronically and diachronically (with a time lag of 12 to 18 months) as well as the direction of these relative influences. Results indicate that (a) at the synchronic level, continuity temporal comparisons have more impact than downward social comparisons on self-rated health; (b) both types of comparison had an independent and positive effect on self-rated health at the diachronic level; (c) self-rated health has an independent synchronic effect on both types of comparison and an independent diachronic effect in temporal comparison.
Wem Medienschönheiten schaden
Authors: Schemer Christian
Published: June 2007

Zusammenfassung. Das vorliegende Experiment untersucht den Einfluss attraktiver Werbemodels auf die Zufriedenheit von Rezipientinnen mit ihrem Aussehen auf Basis der Theorie sozialer Vergleichsprozesse. 94 Versuchspersonen (Durchschnittsalter = 21.8, SD = 3.62) sahen entweder Fotos mit attraktiven (Aufwärtsvergleich) oder unattraktiven Medienakteuren (Abwärtsvergleich). Neben der Vergleichsrichtung wurde die Moderationsfunktion des Selbstwertgefühls untersucht. Dabei zeigt sich, dass Frauen mit geringem Selbstwertgefühl am ehesten anfällig für soziale Aufwärtsvergleiche mit attraktiven Medienakteuren sind und danach am unzufriedensten mit ihrem Aussehen sind. Bei sozialen Vergleichen mit weniger attraktiven Medienakteuren sind Frauen mit hohem und niedrigem Selbstwertgefühl zwar gleichermaßen zufrieden. Dieses Zufriedenheitsniveau entsteht jedoch durch unterschiedliche Prozesse.
Evaluation medienbasierter Lehre mittels der Einschätzung des Kompetenzerwerbs
Authors: Paechter Manuela , Maier Brigitte , Grabensberger Eva
Published: June 2007

Zusammenfassung. Es wurde ein Fragebogen zur Erhebung der Qualität von medienbasierten Lehrveranstaltungen entwickelt, mit Hilfe dessen die Teilnehmer/innen eine Einschätzung ihres Kompetenzerwerbs vornehmen. Der Fragebogen und das ihm zu Grunde liegende Konzept betrachten den Erwerb von Handlungsfähigkeit als eine wesentliche Zielvorstellung universitärer Lehre. Handlungsfähigkeit umfasst in diesem Konzept Sach-, Methoden- und Sozialkompetenz. Sofern es sich um medienbasierte Lehrveranstaltungen handelt, tritt die Vermittlung von Medienkompetenz hinzu. Die hier berichteten statistischen Analysen zur Prüfung der Güte des Messinstruments beruhen auf einer Stichprobe von 122 Personen aus 9 Lehrveranstaltungen. Es wurde eine Analyse der Items, der Reliabilität und der internen Struktur des Fragebogens durchgeführt. Insgesamt konnte ein Instrument entwickelt werden, welches testtheoretische Gütekriterien in gutem Maße erfüllt.
A stochastic approach to analyze trade‐offs and risks associated with large‐scale water resources systems
Authors: Tilmant A. , Kelman R.
Published: June 2007

Water resources development projects often involve multiple and conflicting objectives as well as stochastic hydrologic inputs. Multiobjective optimization techniques can be used to identify noninferior solutions and to construct a trade‐off relationship between conflicting objectives. This paper presents a methodology for analyzing trade‐offs and risks associated with large‐scale water resource projects under hydrologic uncertainty. The proposed methodology relies on the stochastic dual dynamic programming (SDDP) model to derive monthly or weekly operating rules for multipurpose multireservoir systems taking into account the stochasticity of the inflows, irrigation water withdrawals, minimum/maximum flow requirements for navigation, fishing, and/or for ecological purposes. In SDDP, release decisions are chosen so as to minimize the operating costs of a hydrothermal electrical system. Irrigation water demands and other operating constraints are imposed on the system through the SDDP model. The proposed methodology is illustrated with the Southeastern Anatolia Development project, commonly called GAP, in Turkey. The GAP is a multidimensional development project involving primarily the production of hydroelectricity and irrigation. Simulation results using 50 hydrologic scenarios show that the complete development of the irrigation projects would reduce the total energy output by 6.5% and will increase the risk of not meeting minimum outflow at the Syrian border from 5% to 25%.
Arctic and Antarctic polar winter NOx and energetic particle precipitation in 2002–2006
Authors: Seppälä Annika , Verronen Pekka T. , Clilverd Mark A. , Randall Cora E. , Tamminen Johanna , Sofieva Viktoria , Backman Leif , Kyrölä Erkki
Published: June 2007

We report GOMOS nighttime observations of middle atmosphere NO2 and O3 profiles during eight recent polar winters in the Arctic and Antarctic. The NO2 measurements are used to study the effects of energetic particle precipitation and further downward transport of polar NOx. During seven of the eight observed winters NOx enhancements occur in good correlation with levels of enhanced high‐energy particle precipitation and/or geomagnetic activity as indicated by the Ap index. We find a nearly linear relationship between the average winter time Ap index and upper stratospheric polar winter NO2 column density in both hemispheres. In the Arctic winter 2005–2006 the NOx enhancement is higher than expected from the geomagnetic conditions, indicating the importance of changing meteorological conditions.
Effect of Interplanetary Shocks on the AL and Dst Indices
Authors: Mays M. L. , Horton W. , Kozyra J. , Zurbuchen T. H. , Huang C. , Spencer E.
Published: June 2007

The question of how much interplanetary shock (IP) events contribute to the geoeffectiveness of solar wind drivers is assessed through numerical experiments using the WINDMI model, a physics‐based model of the solar wind‐driven magnetosphere‐ionosphere system. Analytic fits to solar wind input parameters (B⊥IMF, usw, nsw) allowed shocks and associated shock‐sheath plasma to be removed while leaving other features of the solar wind driver undisturbed. Percent changes in WINDMI‐derived AL and Dst indices between runs with and without the observed shock and sheath signatures were taken as a measure of its relative contribution to the geoeffectiveness. The major magnetic storms during 15–24 April 2002 and 3–6 October 2000 were selected for this experiment. In both cases, the IP shock and sheath features contributed significantly to the geoeffectiveness of the solar wind driver. The magnetic field compressional jump is important to producing the changes in the AL during these two storm intervals.
State dependent dissociation of HERG channel inhibitors
Authors: Stork D , Timin E N , Berjukow S , Huber C , Hohaus A , Auer M , Hering S
Published: June 2007

Background and purpose:

Inhibition of HERG channels prolongs the ventricular action potential and the QT interval with the risk of torsade de pointes arrhythmias and sudden cardiac death. Many drugs induce greater inhibition of HERG channels when the cell membrane is depolarized frequently. The dependence of inhibition on the pulsing rate may yield different IC50 values at different frequencies and thus affect the quantification of HERG channel block. We systematically compared the kinetics of HERG channel inhibition and recovery from block by 8 blockers at different frequencies.

Experimental approach:

HERG channels were expressed heterologously in Xenopus oocytes and currents were measured with the two‐electrode voltage clamp technique.

Key results:

Frequency‐dependent block was observed for amiodarone, cisapride, droperidol and haloperidol (group 1) whereas bepridil, domperidone, E‐4031 and terfenadine (group 2) induced similar pulse‐dependent block at all frequencies. With the group 1 compounds, HERG channels recovered from block in the presence of drug (recovery being voltage‐dependent). No substantial recovery from block was observed with the second group of compounds. Washing out of bepridil, domperidone, E‐4031 and terfenadine was substantially augmented by frequent pulsing. Mutation D540K in the HERG channel (which exhibits reopening at negative voltages) facilitated recovery from block by these compounds at −140 mV.

Conclusion and implications:

Drug molecules dissociate at different rates from open and closed HERG channels (‘use‐dependent’ dissociation). Our data suggest that apparently ‘trapped’ drugs (group 2) dissociated from the open channel state whereas group 1 compounds dissociated from open and resting states.

British Journal of Pharmacology (2007) 151, 1368–1376; doi:10.1038/sj.bjp.0707356
Ultrasonic guided waves on a periodical grating: Coupled modes in the first Brillouin zone
Authors: Morvan Bruno , Hladky-Hennion Anne-Christine , Leduc Damien , Izbicki Jean-Louis
Published: June 2007

The propagation of Lamb waves in a plate with an engraved periodic grating is addressed in this article. Mode conversions and reflections are analyzed. In the first part the conversion modes are explained by the existence of a resonance condition between the Lamb-wave wavenumbers and the fundamental and harmonic spatial periods of the grating. These phenomena are experimentally and numerically highlighted for a metallic waveguide with a rectangular grating. The second part focuses on the pseudo-Lamb wave dispersion curves in a periodic waveguide. The periodicity implies that the Lamb waves dispersion curves fold back at the edge of the Brillouin zone. Several stop bands appear: classical band gaps at the boundary of the Brillouin zone and mini-stop-bands inside the Brillouin zone. For the ministop band, dispersion curves cross and a possible coupling occurs between the modes. Finally, conversions or the existence of gaps are linked with the Power Spectral Density of the grating profile.
Synthesis of high yield single helical carbon microsprings by catalytic chemical vapor deposition and an experimental investigation of their growth mechanism
Authors: Xie Jining , Varadan V. K.
Published: June 2007

A type of single helical carbon microsprings (SHCMSs) was synthesized by catalytic chemical vapor deposition. The as-prepared SHCMSs were characterized by a number of techniques such as scanning and transmission electron microscopy, x-ray powder diffraction, and x-ray photoelectron spectroscopy. Experimental results indicate that during the synthesis both morphology change and crystalline phase transformation occur for cobalt catalytic particles and certain chemical bonding form between cobalt and sulfur atoms. Based on the data from this study, a possible growth mechanism of SHCMSs was discussed.
New generation of the reference interaction site model self-consistent field method: Introduction of spatial electron density distribution to the solvation theory
Authors: Yokogawa Daisuke , Sato Hirofumi , Sakaki Shigeyoshi
Published: June 2007

The authors propose the new generation of the reference interaction site model self-consistent field (RISM-SCF) method for the solvation effect on the electronic structure of a solute molecule, in which the procedure proposed by Gill et al. [J. Chem. Phys. 96, 7178 (1992)] is adopted. Main improvements are the introduction of spatial electron density distribution and the removal of the grid dependency that is inherent in the original RISM-SCF. The procedure also provides very stable determination of the effective charges even if a buried atom exists in the target molecule and eventually extends the applicability of the RISM-SCF. To demonstrate the superiority of our method, sample calculations for H2O, C2H5OH, and HLi in aqueous solution are presented.
Development of a vitamin-protein sensor based on carbon nanotube hybrid materials
Authors: Hirata Takamichi , Amiya Shoji , Akiya Masahiro , Takei Osamu , Sakai Takafumi , Hatakeyama Rikizo
Published: June 2007

A bionanosensor consisting of a field effect transistor chip and containing a mixture of poly(ethylene glycol)-grafted single-walled carbon nanotubes (SWCNTs) and SWCNTs modified with a protein (avidin) which binds with a specific vitamin (biotin) is developed. An increase in impedance due to biotin-avidin binding is observed when biotin is injected, while the injection of other vitamins resulted in a decrease in impedance. This bionanosensor reacts quickly (∼60s); in addition, the impedance recovers almost to its initial value when the bionanosensor is washed with distilled water; thus, the vitamins do not bind directly with the SWCNTs.
Parallel preparation of highly spin-polarized electrons in single InAs∕GaAs quantum dots
Authors: Löffler W. , Hetterich M. , Mauser C. , Li S. , Passow T. , Kalt H.
Published: June 2007

Initialization of electron spins in semiconductor quantum dots (QDs) is a major prerequisite for a successful implementation of such QDs in quantum information applications. It is essential that the initialization is achieved for many individually separable dots in parallel. Here the authors show that exactly this can be accomplished with near-unity fidelity by electrical spin injection from the diluted magnetic semiconductor ZnMnSe into InAs∕GaAs quantum dots. The deviation from unity is smaller than 0.13, more precise determination is limited by the signal-to-noise ratio of their setup. They demonstrate the robust concurrent initialization of several quantum dots with the same high fidelity.
Effects of Li content on the phase structure and electrical properties of lead-free (K0.46−x∕2Na0.54−x∕2Lix)(Nb0.76Ta0.20Sb0.04)O3 ceramics
Authors: Chang Yunfei , Yang Zupei , Hou Yuting , Liu Zonghuai , Wang Zenglin
Published: June 2007

Lead-free (K0.46−x∕2Na0.54−x∕2Lix)(Nb0.76Ta0.20Sb0.04)O3 piezoelectric ceramics were prepared by the conventional solid state sintering method without cold-isostatic pressing process. The x-ray diffraction and Raman scattering results show that the phase structure of the ceramics undergoes a transition from pseudocubic to tetragonal phase with increasing x from 0 to 0.10. Significantly enhanced electrical properties (d33=259pC∕N, kp=0.42, εr=1653, and tan δ=0.027) were obtained in the ceramics with x=0.04 near the morphotropic phase boundary, and only the tetragonal-cubic phase transition was observed above the room temperature in the εr-T curve. The temperature stability of the ceramics with x=0.04 was also investigated.
Effects of surface elasticity and residual surface tension on the natural frequency of microbeams
Authors: Wang Gang-Feng , Feng Xi-Qiao
Published: June 2007

Surface effects often play a significant role in the physical properties of micro- and nanosized materials and structures. In this letter, the authors presented a theoretical model directed towards investigation of the effects of both surface elasticity and residual surface tension on the natural frequency of microbeams. A thin surface layer was introduced on the upper and lower surfaces to rationalize the near-surface material properties that are different from the bulk material. An explicit solution is derived for the natural frequency of microbeams with surface effects. This study might be helpful for the design of microbeam-based sensors and some related measurement techniques.
Continuous wave and passively Q-switched laser performance of a Nd-doped mixed crystal Nd:Lu0.5Gd0.5VO4
Authors: Yu Haohai , Zhang Huaijin , Wang Zhengping , Wang Jiyang , Yu Yonggui , Shao Zongshu , Jiang Minhua , Zhang Xingyu
Published: June 2007

The authors reported continuous wave (cw) and passively Q-switched laser performances of Nd:Lu0.5Gd0.5VO4 crystal at 1.06μm. cw output power of 6.65W was obtained under the incident pump power of 13.75W with slop efficiency of 51%. In the passively Q-switched operation, the shortest pulse width, largest pulse energy, and highest peak power were achieved to be 6.2ns, 192.5μJ, and 31.06kW, respectively, with Cr4+ doped yttrium aluminum garnet crystals as the saturable absorbers.
Large magnetocaloric effect in spinel CdCr2S4
Authors: Yan L. Q. , Shen J. , Li Y. X. , Wang F. W. , Jiang Z. W. , Hu F. X. , Sun J. R. , Shen B. G.
Published: June 2007

Magnetocaloric effect in CdCr2S4 was investigated by magnetization and heat capacity measurements. CdCr2S4 is of a cubic spinel structure with soft ferromagnetism and performs reversible magnetic entropy in the whole experimental temperature range from 56to128K. A large magnetic entropy change ∼7.04J∕kgK and adiabatic temperature change ΔTad∼2.6K are revealed for a field change of 0–5T near the Curie temperature of 87K. These results suggest that sulfospinel probably is a promising candidate as working material in magnetic refrigeration technology.
Solitary and shock waves in discrete strongly nonlinear double power-law materials
Authors: Herbold E. B. , Nesterenko V. F.
Published: June 2007

A laminar metamaterial supporting strongly nonlinear solitary and shock waves with impact energy mitigating capabilities is presented. It consists of steel plates with intermittent polymer toroidal rings acting as strongly nonlinear springs with large allowable strain. The force-displacement relationship of a compressed o-ring is described by the addition of two power-law relationships resulting in a solitary wave speed and width depending on the amplitude. This double nonlinearity allows splitting of an initial impulse into three separate strongly nonlinear solitary wave trains. Solitary and shock waves are observed experimentally and analyzed numerically in an assembly with Teflon o-rings.
Microstructural stability of nanocrystalline LiCoO2 in lithium thin-film batteries under high-voltage cycling
Authors: Li Chiung-Nan , Yang Jenn-Ming , Krasnov Victor , Arias Jeff , Nieh Kai-Wei
Published: June 2007

The microstructural stability of nanocrystalline LiCoO2 cathodes in rechargeable thin-film batteries after high-voltage cycling was investigated by transmission electron microscopy. It was found that besides the trigonal-LiCoO2 phase, there are two other phases of LixCoO2, spinel and H1–3, that form inside the nanocrystalline cathode after electrochemical cycling (charge cutoff voltages ≧4.5V). The formation of the aforementioned secondary phases in the cathode material is irreversible and leads to capacity loss in lithium thin-film batteries.
Cross-peak-specific two-dimensional electronic spectroscopy
Authors: Read Elizabeth L. , Engel Gregory S. , Calhoun Tessa R. , Mančal Tomáš , Ahn Tae Kyu , Blankenship Robert E. , Fleming Graham R.
Published: June 2007

Intermolecular electronic coupling dictates the optical properties of molecular aggregate systems. Of particular interest are photosynthetic pigment–protein complexes that absorb sunlight then efficiently direct energy toward the photosynthetic reaction center. Two-dimensional (2D) ultrafast spectroscopy has been used widely in the infrared (IR) and increasingly in the visible to probe excitonic couplings and observe dynamics, but the off-diagonal spectral signatures of coupling are often obscured by broad diagonal peaks, especially in the visible regime. Rotating the polarizations of the laser pulses exciting the sample can highlight certain spectral features, and the use of polarized pulse sequences to elucidate cross-peaks in 2D spectra has been demonstrated in the IR for vibrational transitions. Here we develop 2D electronic spectroscopy using cross-peak-specific pulse polarization conditions in an investigation of the Fenna–Matthews–Olson light harvesting complex from green photosynthetic bacteria. Our measurements successfully highlight off-diagonal features of the 2D spectra and, in combination with an analysis based on the signs of features arising from particular energy level pathways and theoretical simulation, we characterize the dominant response pathways responsible for the spectral features. Cross-peak-specific 2D electronic spectroscopy provides insight into the interchromophore couplings, as well as into the energetic pathways giving rise to the signal. With femtosecond resolution, we also observe dynamical processes that depend on these couplings and interactions with the protein environment.
Network structure of cerebral cortex shapes functional connectivity on multiple time scales
Authors: Honey Christopher J. , Kötter Rolf , Breakspear Michael , Sporns Olaf
Published: June 2007

Neuronal dynamics unfolding within the cerebral cortex exhibit complex spatial and temporal patterns even in the absence of external input. Here we use a computational approach in an attempt to relate these features of spontaneous cortical dynamics to the underlying anatomical connectivity. Simulating nonlinear neuronal dynamics on a network that captures the large-scale interregional connections of macaque neocortex, and applying information theoretic measures to identify functional networks, we find structure–function relations at multiple temporal scales. Functional networks recovered from long windows of neural activity (minutes) largely overlap with the underlying structural network. As a result, hubs in these long-run functional networks correspond to structural hubs. In contrast, significant fluctuations in functional topology are observed across the sequence of networks recovered from consecutive shorter (seconds) time windows. The functional centrality of individual nodes varies across time as interregional couplings shift. Furthermore, the transient couplings between brain regions are coordinated in a manner that reveals the existence of two anticorrelated clusters. These clusters are linked by prefrontal and parietal regions that are hub nodes in the underlying structural network. At an even faster time scale (hundreds of milliseconds) we detect individual episodes of interregional phase-locking and find that slow variations in the statistics of these transient episodes, contingent on the underlying anatomical structure, produce the transfer entropy functional connectivity and simulated blood oxygenation level-dependent correlation patterns observed on slower time scales.
Central histamine H3receptor signaling negatively regulates susceptibility to autoimmune inflammatory disease of the CNS
Authors: Teuscher Cory , Subramanian Meena , Noubade Rajkumar , Gao Jian Feng , Offner Halina , Zachary James F. , Blankenhorn Elizabeth P.
Published: June 2007

Histamine (HA), a biogenic amine with a broad spectrum of activities in both physiological and pathological settings, plays a key regulatory role in experimental allergic encephalomyelitis, the autoimmune model of multiple sclerosis. HA exerts its effect through four G protein-coupled receptors designated HA receptor H1, H2, H3, and H4. We report here that, compared with wild-type animals, mice with a disrupted HA H3receptor (H3RKO), the expression of which is normally confined to cells of the nervous system, develop more severe disease and neuroinflammation. We show that this effect is associated with dysregulation of blood–brain barrier permeability and increased expression of MIP-2, IP-10, and CXCR3 by peripheral T cells. Our data suggest that pharmacological targeting of the H3R may be useful in preventing the development and formation of new lesions in multiple sclerosis, thereby significantly limiting the progression of the disease.
TORC2 regulates germinal center repression of the TCL1 oncoprotein to promote B cell development and inhibit transformation
Authors: Kuraishy Ali I. , French Samuel W. , Sherman Mara , Herling Marco , Jones Dan , Wall Randolph , Teitell Michael A.
Published: June 2007

Aberrant expression of the TCL1 oncoprotein promotes malignant transformation of germinal center (GC) B cells. Repression ofTCL1in GC B cells facilitates FAS-mediated apoptosis and prevents lymphoma formation. However, the mechanism for this repression is unknown. Here we show that the CREB coactivator TORC2 directly regulatesTCL1expression independent of CREB Ser-133 phosphorylation and CBP/p300 recruitment. GC signaling through CD40 or the BCR, which activates pCREB-dependent genes, caused TORC2 phosphorylation, cytosolic emigration, andTCL1repression. Signaling via cAMP-inducible pathways inhibitedTCL1repression and reduced apoptosis, consistent with a prosurvival role for TCL1 before GC selection and supporting an initiating role for aberrantTCL1expression during GC lymphomagenesis. Our data indicate that a novel CREB/TORC2 regulatory mode controls the normal program of GC gene activation and repression that promotes B cell development and circumvents oncogenic progression. Our results also reconcile a paradox in which signals that activate pCREB/CBP/p300 genes concurrently repressTCL1to initiate its silencing.
Hospital Versus Home Care for the Acutely Mentally Ill? Preferences of Caregivers Who Have Experienced Both Forms of Service
Authors: Fulford Megan , Farhall John
Published: June 2007

Objective: Demonstration studies of community treatment as an alternative to hospitalization have reported high degrees of satisfaction by family carers. We aimed to determine the extent of carer preference for hospital versus community treatment for acute mental illness in a routine setting where carers had experienced both service types.

Method: Patients who had contact with both a hospital inpatient service and a Crisis Assessment and Treatment (CAT) team within the previous 5 years were identified. Seventy-seven family carers of these patients completed a questionnaire which identified their preference for services, and psychological and demographic variables likely to be predictive of their choice.

Results: Only half the carers preferred a CAT service to treat their relative in the event of a future relapse. Psychological variables were better predictors of choice than were demographic variables.

Conclusions: The proportion of caregivers who prefer community treatment for acute psychosis may be smaller than previously thought. The lower carer satisfaction found here may be associated with the short-term interventions of Victoria's CAT teams, the severity of acute relapses and the duration of the patient's mental health problem.
Child and Young Adolescent Suicide in New Zealand
Authors: Beautrais Annette L
Published: June 2007

Objective: To describe the epidemiology and characteristics of all suicide deaths among under 15-year-olds in New Zealand over a 10-year period.

Method: In a 10-year retrospective study the features of all 61 children and young adolescents aged less than 15 years who died by suicide in New Zealand from 1989 to 1998 were examined by review of coronial files.

Results: Suicide among under 15-year-olds is very rare but increasing. Suicide risk increases with age: the majority of those who die are aged 14 years (57.4% of the total) or 13 years (26.2%). Boys (72.1%) and Maori (57.4%) predominate. Most suicides occurred in children not living in intact biological families (67.2%). Hanging was the predominant method (78.7%). One in three children left suicide notes. One in four had a history of contact with social welfare authorities. There was a family history of suicide in 10% of cases. A minority had a documented history of prior suicide attempts (13.1%) or mental health problems (23%). One in four (23%) was reported to have made threats of suicide within the year prior to their death. A majority of deaths appeared to have been precipitated by relatively minor family arguments or disciplinary events, which, however, occurred in the context of actual or anticipated disruptions or transitions in family living arrangements or school circumstances, or severe family problems.

Conclusions: In general, the impression of young adolescent suicide was of a disadvantaged, vulnerable and distressed group of adolescents growing up in extremely difficult circumstances. Maori children predominate in this group. There is clearly a need to verify these impressions with an in-depth investigation of the familial and social circumstances of children who die by suicide. Such investigations might best be conducted by annual mortality review and monitoring of all young adolescent suicides.
The NISAD Schizophrenia Research Register: why do we need a database of schizophrenia volunteers?
Authors: Loughland Carmel M. , Carr Vaughan J. , Lewin Terry J.
Published: June 2007

Objective: This paper documents the establishment of the Schizophrenia Research Register of the Neuroscience Institute of Schizophrenia and Allied Disorders (NISAD). This register aims to provide a volunteer pool of people with a clinical diagnosis of schizophrenia who are willing to consider participating in research projects. This unique resource is accessible to the general scientific research community.

Method: The Register, which operates as a standalone, computerized relational database, maintains demographic and clinical information about individuals with schizophrenia recruited through media campaigns, and general health and non-government support agencies. Preliminary data are reported on the first 400 people with schizophrenia who registered on the database, together with selected comparisons with data from the national Low Prevalence (psychotic) Disorders Study (LPDS).

Results: Individuals currently on the Register have a mean age of 38.74 years (SD = 11.41) and are predominantly Australian born (85.1%), which is consistent with data from the LPDS. However, the gender distribution is more balanced compared with the LPDS (53.8% vs 65.4% males) and proportionately more registrants are married or in de facto relationships (18.4% vs 10.8%). Registrants also tend to have lower current symptomatology and higher functioning relative to participants in the LPDS.

Conclusions: The Register provides a unique and invaluable educational and research resource, as well as a complementary recruitment source for researchers who would otherwise rely on samples drawn primarily from mental health services.
Cluster Analysis in Educational Research
Authors: Egan Owen
Published: June 2007

This paper examines the use of cluster analysis in educational research. Its first conclusion is that the important issues are not technical but interpretative. While we must, of course, reject clusters which fail to meet minimum technical requirements, it does not follow that those which are technically admissable are therefore meaningful explanatory constructs. In general, I will argue, they are not.

The principal difficulty with cluster analysis is that it introduces a concept of ‘type’ which is unscientific. As a result, we become embroiled with character‐sketches and pen‐pictures more appropriate to literature than to research. This point has been touched on by critics who find cluster analysis to be ‘gross' in certain respects: in its “failure to pinpoint significant teaching variables”, in its tendency to “intensify” what are described as “unproductive polarizations” (Elliott, 1978, p. 77), in its propagation of “emotionally laden catch‐all terms” (Wragg, 1976, p. 285). The second conclusion of the paper is that when the ‘grossness' of cluster analysis is understood and accepted, the technique can nonetheless serve an important heuristic function, provided certain conditions are met. The paper refers to the Lancaster and ORACLE studies to illustrate the problems and possibilities for cluster analysis in educational research. It ends with some recommendations.
Some Characteristics of Interaction in Foreign Language Classrooms
Authors: Westgate David , Batey John , Brownlee Jane , Butler Mike
Published: June 2007

The authors intend to direct attention, through this report of a collaborative, school‐based study, towards the interactional processes which characterise secondary foreign language (FL) lessons. It is argued that, since these processes have an influential effect upon pupils' learning and attitudes, this kind of research can yield important insights for an area of the curriculum which has many current problems and which is relatively unpopular with pupils. The methodology employed blends discourse analysis with ethnographic procedures and aims to identify patterns of teacher‐pupil interaction. Degrees of teacher‐dominance in FL lessons are related to constraints which derive from the subject‐matter and purposes of language teaching. Teacher‐strategies, and their implications for pupils' viewpoints of the subject, are considered; and fruitful lines of further research are indicated.
Associations between Preschool Reading Related Skills and later Reading Achievement
Authors: Blatchford Peter , Burke Jessica , Farquhar Clare , Plewis Ian , Tizard Barbara
Published: June 2007

This paper is about the extent of children's reading related knowledge and associations with reading achievement at seven years. It presents results, from a major longitudinal study of children's progress in 33 Inner London Education Authority (ILEA) infant schools, on six measures of preschool reading related knowledge—word matching, concepts about print, letter identification, word reading, handwriting, and oral vocabulary—and their associations with Young's Group Reading scores at seven years. The strongest association was between letter identification and reading at seven. Preschool oral vocabulary and handwriting were also significantly and independently related to reading at seven, though concepts about print, in contrast to other recent research, was no more related to later reading than was word matching. Results are set in the context of conflicting theories about the early teaching of reading and, in particular, about conflicting views on the extent of preschool reading related skills and which skills have the most relevance to later reading achievement.
Ethnicity and Conflict in Physical Education
Authors: Carroll Bob , Hollinshead Graeme
Published: June 2007

There has been little research dealing with the issues of teaching ethnic minority groups in physical education (PE), in particular that which takes the perceptions of teachers and their pupils as the focal point to examine the issues and conflicts. This research takes a social action perspective by studying Muslim children in a northern comprehensive school. The areas of conflict are highlighted, such as PE kit, showers, Ramadan and extra‐curricular activities, through the pupils’ perceptions. This leads to a discussion on the clash of values between the PE teachers with their traditional values of PE and the Muslim cultural values. In particular it points out the dilemma of following policies of equality of opportunity at the same time as multicultural and anti‐racist ones in PE, the lack of awareness of Muslim values and feelings on behalf of the PE teachers; and the way the child is caught between the two cultures and values. The research points to the need for better preparation of teachers, in‐service education and training, anti‐racist policies and links with the community at the educationist's level, and the dilemma posed by empowerment at the political level. The discussion locates the issues in PE in the wider education and societal debate of different cultures.