bluuebunny/crossref_metadata_2025 huggingface dataset:
Deposition of Functional Organic Thin Films by Pulsed Plasma Polymerization: A Joint Theoretical and Experimental Study
Authors: Denis Laurent , Marsal Philippe , Olivier Yoann , Godfroid Thomas , Lazzaroni Roberto , Hecq Michel , Cornil Jérôme , Snyders Rony
Published: December 2009

The pulsed plasma polymerization of allylamine and cyclopropylamine is investigated to study the influence of the precursor chemical structure on the process selectivity toward the primary amine groups. Both systems are compared under similar mean powers injected in the discharges (Pmean). The results reveal an increase in the precursor fragmentation in the plasma and a decrease in the primary amine content of the film (%NH2) as Pmean increases. Nevertheless, below a critical Pmean value, different behaviors are observed depending on the precursor, cyclopropylamine being less plasma‐fragmented than allylamine. As a result, plasma polymer films (PPF) synthesized from cyclopropylamine yield the largest %NH2. These results are rationalized with the help of theoretical calculations pointing to a preferential opening of the cyclopropylamine ring structure. Cyclopropylamine activation in the plasma can thus be achieved without fragmentation reactions, leading to a more efficient incorporation of the NH2 group of the precursor in the PPF.

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Climatic and geomorphic factors affecting contemporary (1950–2004) activity of retrogressive thaw slumps on the Aklavik Plateau, Richardson Mountains, NWT, Canada
Authors: Lacelle Denis , Bjornson Jean , Lauriol Bernard
Published: December 2009

The climatic and geomorphic factors affecting retrogressive thaw slump initiation and activity on the Aklavik Plateau (Richardson Mountains, NWT) were examined using historical air photographs over a 54‐year period (1950 to 2004). In this region, thaw slumps include a near‐vertical headwall, a floor of low gradient (2–10°) and a steeply sloping evacuation channel (15–25°) that connects the floor of the thaw slumps to Willow River located 60–150 m below. All thaw slumps on the Aklavik Plateau are located within the glacial limit of the Laurentide Ice Sheet and the majority developed on the western side of the valley on gently sloping terrain. Aerial photographic analysis showed an increase in thaw slump initiation from 0.35 new thaw slump yr−1 over the 1954–71 period to 0.68 new thaw slump yr−1 over the 1985–2004 period. This increase follows the pattern of the 10‐year running mean summer air temperature record over the 1950–2004 period. However, the total number of active mature thaw slumps on the Aklavik Plateau decreased from a maximum of 46 in 1950 to a minimum of 24 observed in 2004, which follows, to a certain extent, the 10‐year running average of rainfall. Both these trends may relate to the influence of climate on the erosional processes that are thought to initiate thaw slumps and keep them active in regions of highlands. Copyright © 2009 John Wiley & Sons, Ltd. and Her Majesty the Queen in right of Canada.
Hydrological and geomorphological significance of rock glaciers in the dry Andes, Chile (27°–33°S)
Authors: Azócar G. F. , Brenning A.
Published: December 2009

The latitudinal‐altitudinal distribution of rock glaciers in the dry Chilean Andes between 27° and 33°S was analysed and their hydrological and geomorphological significance evaluated. Statistical estimation techniques were used based on digital elevation models and air photo interpretation, and sediment budget models were applied to assess surface‐lowering rates. The estimated specific density of rock glaciers in the study area is 1.4 per cent, which corresponds to 147.5 km2 and a water equivalent of 2.37 km3. A comparison with glacier water equivalents derived from revised glacier inventory data shows that rock glaciers are more significant stores of frozen water than glaciers between 29° and 32°S. The latitudinal‐altitudinal distribution of rock glacier limits roughly follows the mean annual air 0°C isotherm, but in the southern part of the study area it extends into elevations where modern regional mean annual air temperatures exceed 0°C. High Andean surface‐lowering rates inferred from rock glacier sediment budget models are in the order of 0.6–0.7 mm yr−1, which is comparable to previous results from the dry Chilean Andes, but lower than in the more humid Andes further south. Copyright © 2009 John Wiley & Sons, Ltd.
Optical characterisation of BiFeO3 epitaxial thin films grown by pulsed‐laser deposition
Authors: Himcinschi Cameliu , Vrejoiu Ionela , Friedrich Marion , Ding Li , Cobet Christoph , Esser Norbert , Alexe Marin , Zahn Dietrich R. T.
Published: December 2009

Epitaxial thin films of bismuth ferrite, BiFeO3, were deposited by pulsed laser deposition (PLD) on SrTiO3 (100), Nb‐doped SrTiO3 (100) and DyScO3 (110) substrates. Ellipsometric spectra are obtained in the energy range 0.73‐9.5 eV by combining Variable Angle Spectroscopic Ellipsometry (VASE) and vacuum ultraviolet (VUV) ellipsometry with synchrotron radiation. The optical constants of BiFeO3 films were determined by analysing the ellipsometric spectra with a model that describes the optical response of a system consisting of air, film and substrate. The shift towards higher energies of the refractive index and extinction coefficient of the film deposited onto Nb‐doped SrTiO3 as compared with that deposited onto DyScO3 was attributed to a more compressive in‐plane epitaxial strain. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ta‐C/Si heterojunction diodes with apparently giant ideality factors
Authors: Brötzmann Marc , Vetter Ulrich , Hofsäss Hans
Published: December 2009

A common feature of many wide band gap heterojunction diodes is an unexplained large ideality factor n > 2. In this context we investigate the diode characteristics of heterojunction diodes consisting of a crystalline semiconductor material such as Si covered with a thin semiconducting film of amorphous or disordered material. As thin amorphous film we use tetrahedral amorphous carbon (ta‐C). These heterojunctions exhibit a pronounced rectifying behavior, low saturation current and low parasitic currents. Moreover, we observe an apparently giant ideality factor reaching values of n > 75. As a consequence, the turn on voltage is around 3 – 10 V and the I‐V curves can be measured for bias up to 40 V without reaching saturation or electrical breakdown.

We present a quantitative model for the unusual diode characteristics of these Metal – Amorphous Semiconductor – Semiconductor diodes (MASS‐diodes). We demonstrate that the I‐V characteristics of the heterojunctions are well described by a serial arrangement of an ideal Schottky‐diode, a Frenkel‐Poole type resistance and an Ohmic contact resistance, emulating a p‐n‐ or Schottky diode characteristic with giant ideality factor and referred to as the FPID‐model. We propose that heterojunctions exhibiting apparently large ideality factors n ≫ 2 may possess an interfacial disordered or amorphous layer with Frenkel‐Poole conduction properties. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Indium tin oxide on copper phthalocyanine – an ellipsometry study
Authors: Friedrich Marion , Kupfer Hartmut , Zahn Dietrich R. T.
Published: December 2009

Spectroscopic ellipsometry was employed to evaluate the influence of ITO deposition on underlying copper phthalocyanine (CuPc) thin films grown on silicon with native oxide. At first the dielectric functions of ITO and copper phthalocyanine were derived from a multi‐sample analysis of single layer samples. While the CuPc films were isotropic in the substrate plane they showed a strong anisotropy in their optical response perpendicular to the film plane. Obvious higher values were observed below 1.9 eV for the real part, and over the whole spectral range (0.7 – 5 eV) for the imaginary part of the dielectric function perpendicular to the film plane. The dielectric functions were applied to model the double layer samples with ITO on top, resulting in a good match of modelled and measured ellipsometry spectra. This is a clear indication that the ITO deposition does not destroy or strongly modify the optically anisotropic CuPc layer. In a next step the CuPc dielectric function was varied to improve the fit resulting in a slight line shape change. This change might be a hint for possible phase transformation of a small part of the CuPc from α to β phase due to ITO deposition. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of the band offsets between ultrathin GaN(000) layers and sapphire (0001) by photoelectron spectroscopy
Authors: Hamsen C. , Lorenz P. , Schaefer J. A. , Krischok S.
Published: December 2009

Ultrathin layers of N‐face GaN(000) on c‐plane sapphire have been grown via plasma assisted molecular beam epitaxy (PAMBE) and investigated in‐situ via reflection of high energy electron diffraction (RHEED), Xray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Our studies of the electronic interface between substrate and adsorbate reveal a band offset about (1.7 ± 0.1) eV at the GaN‐sapphire interface and an additional band bending of the GaN layer of 0.4 eV within the first 3 nm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure determination of Pd‐catalyst supported on S‐terminated GaAs(001) using DFT calculation
Authors: Ishii Akira , Asano Hiroki , Yokoyama Mami , Tsukamoto Shiro , Shuto Satoshi , Arisawa Mitsuhiro
Published: December 2009

The density functional calculation is performed to determine the structure of the reused palladium catalyst on sulphur terminated GaAs(001) surface for the Heck reaction. The DFT calculation has been done for S‐terminated GaAs(001) surface with and without As of the topmost layer. The difference the two model of the S‐terminated GaAs(001) is very small. Since, for both case, the binding energy of palladium atom is stronger due to the co‐adsorption of sulphur, the role of sulphur is to make the binding of palladium stronger. Moreover, the heights of the position of the adsorbed palladium atom for both model cases are lower than sulphur atom on the surface. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic ellipsometry and reflection anisotropy spectroscopy of lutetium diphthalocyanine films on silicon
Authors: Seidel Falko , Fronk Michael , Himcinschi Cameliu , Chis Vasile , Zahn Dietrich R. T.
Published: December 2009

The main aim of this work is to investigate organic thin films by the use of Reflection Anisotropy Spectroscopy (RAS) and Spectroscopic Ellipsometry (SE) in situ during growth of the thin films on silicon substrates. The investigated material is the rare‐earth diphthalocyanine LuPc2. The LuPc2 films were deposited on hydrogen passtivated Si(111) and on oxidised Si substrates by Organic Molecular Beam Deposition (OMBD). The films on H‐Si(111) show a high anisotropic behaviour. Model calculations for in situ SE measurements revealed angles between θ = 60° and 90° for LuPc2 on H‐Si(111). Furthermore, the energy transitions found match to those determined by Density Functional Theory calculations (DFT). (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heterointerface relief in the (311)A‐oriented GaAs‐AlAs superlattices
Authors: Gulyaev Dmitry , Zhuravlev Konstantin
Published: December 2009

The low‐temperature steady‐state photoluminescence (PL) and the PL kinetics of the type II (100)‐ and (311)A‐oriented GaAs/AlAs superlattices (SLs) in the electric field were studied to define the parameters of the heterointerfaces relief in the (311)A‐SLs. The electric field leads to the isotropic reduction in the PL intensity and acceleration of the PL kinetics of the (100)‐SL, whereas these effects in the (311)A‐SL are anisotropic. These electric field effects in the steady‐state PL and the PL kinetics of the (100)‐ and (311)A‐SLs are caused by the transfer and capture of the carriers at the nonradiative recombination centers. These carriers are originally localized in the wide quantum wells which appear due to the heterointerface roughness. According to the data obtained the lateral sizes of the microcavities in the [01] directions both in the direct and invert faceted heterointerfaces of the (311)A‐SL exceed 3.2 nm and the modulation of the AlAs layer width is 0.8–1.2 nm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ Raman growth monitoring of indium/copper phthalocyanine interfaces
Authors: Schäfer Philipp , Himcinschi Cameliu , Chis Vasile , Zahn Dietrich R. T.
Published: December 2009

Interface formation between indium and copper phthalocyanine (CuPc) is investigated using in situ Raman spectroscopy. CuPc and indium are deposited onto hydrogen passivated Si (111) surfaces via molecular beam deposition under ultra high vacuum (UHV) conditions. The 647.1 nm excitation wavelength of the Krypton laser fulfils resonance conditions for the CuPc molecules and provides a reasonable signal‐to‐noise ratio for thin films in the nanometer regime even for accumulation times below one minute. Indium clusters are formed at the interface and the surface enhanced Raman spectroscopy (SERS) effect is observed. A comparison of the spectra with results of density functional theory (DFT) calculations do not support a formerly proposed structure of CuPc/indium mixed layers with covalent‐like bonds [1]. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ZnO films deposited by optimized PLD technique with bias voltages
Authors: Yamaguchi Hiroyuki , Shitara Tamae , Komiyama Takao , Chonan Yasunori , Aoyama Takashi
Published: December 2009

The pulsed laser deposition (PLD) technique with bias voltage application for formation of high quality ZnO films was investigated. Oxygen ambient in the PLD chamber significantly decreased the photoluminescence (PL) intensity of near band edge (NBE) emission. Then, instead of using oxygen ambient, the PLD technique with bias voltage application was optimized to attain the stoichiometric composition of the ZnO films. As the deposition temperature was increased, the X‐ray spectrum width diffracted from the (0002) planes was decreased and it showed a minimum value at 700 °C. The PL intensity of the NBE emission also had its maximum value for the film deposited at 700 °C. For the ZnO films deposited at 700 °C, the X‐ray spectrum width showed the minimum value under a bias voltage of –50 V. The PL intensity of the NBE emission also had a maximum value under the same bias voltage. Thus, ZnO films deposited under a bias voltage of –50 V at 700 °C had strong NBE emission intensities. These results could be explained not only by attaining the stoichiometric composition of the ZnO film but also by decreasing the number of high energy O2– ions which caused non‐radiative recombination centers in the film. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement of sol‐gel ZnO heterojunctions by hydrogen annealing
Authors: Abe Kazunori , Komiyama Takao , Chonan Yasunori , Yamaguchi Hiroyuki , Aoyama Takashi
Published: December 2009

ZnO films were formed quartz substrates and silicon (100) wafers by a sol‐gel technique, and they were crystallized (in air at 800 °C) and annealed in hydrogen (at 220 to 420 °C, for 10 to 120 min). Photoluminescence (PL) measurements of ZnO films on quartz substrates indicated that hydrogen annealing increased the near band edge (NBE) emission ten‐fold, but it only slightly decreased the deep level emission (DLE). Hall effect measurements showed an n‐type conduction of the films, with an electron concentration of about 1016 cm–3, Hall mobility of about 14 cm2/Vs, and resistivity of about 2 Ωcm. Before hydrogen annealing, n‐ZnO/p‐Si heterojunctions showed only ohmic behavio. After hydrogen annealing, however, the forward current was increased and the reverse current was decreased, and the final I‐V curve showed a typical rectifying characteristicc. These results can be explained by a conventional polycrystalline and grain boundary (GB) model with a potential barrier height near the GBs and defects in the grains. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Confirmatory analysis for phase III population pharmacokinetics
Authors: Hu Chuanpu , Zhang Ji , Zhou Honghui
Published: December 2009

Population pharmacokinetics (POPPK) has many important uses at various stages of drug development and approval. At the phase III stage, one of the major uses of POPPK is to identify covariate influences on human pharmacokinetics, which is important for potential dose adjustment and drug labeling. One common analysis approach is nonlinear mixed‐effect modeling, which typically involves time‐consuming extensive search for best fits among a large number of possible models. We propose that the analysis goal can be better achieved with a more standard confirmatory statistical analysis approach, which uses a prespecified primary analysis and additional sensitivity analyses. We illustrate this approach using a phase III study data set and compare the result with that calculated using the common exploratory approach. We argue that the confirmatory approach not only substantially reduces analysis time but also yields more accurate and interpretable results. Some aspects of this confirmatory approach may also be extended to data analysis in earlier stages of clinical drug development, i.e. phase II and phase I. Copyright © 2009 John Wiley & Sons, Ltd.
β‐secretase inhibitory effects of furanocoumarins from the root of Angelica dahurica
Authors: Marumoto Shinsuke , Miyazawa Mitsuo
Published: December 2009

In the course of screening antidementia agents from natural products, five β‐secretase (BACE1) inhibitors were isolated from the root extract of Angelica dahurica (Umbelliferae). They were identified as furanocoumarins, isoimperatorin (1), imperatorin (2), (+)‐oxypeucedanin (3), (+)‐byakangelicol (4) and (+)‐byakangelicin (5). Among them, compounds 2 and 4 showed significant inhibitory activity against β‐secretase (BACE1) with IC50 values of 91.8 ± 7.5 and 104.9 ± 2.4 μM, respectively. Compounds 1‐5 inhibited BACE1 activity in a dose‐dependent manner. Copyright © 2009 John Wiley & Sons, Ltd.
Cornin ameliorates cerebral infarction in rats by antioxidant action and stabilization of mitochondrial function
Authors: Jiang Wang‐Lin , Zhang Shu‐Ping , Zhu Hai‐Bo , Jian‐Hou  , Tian Jing‐Wei
Published: December 2009

This study was conducted to investigate the efficacy of cornin, an iridoid glycoside, in an experimental cerebral ischemia induced by middle cerebral artery occlusion (MCAO) and reperfusion (I/R), and to elucidate the potential mechanism. Adult male Sprague‐Dawley rats were subjected to MCAO for 1 h, then reperfusion for 23 h. Behavioral tests were used to evaluate the damage to central nervous system. The cerebral infarct volume and histopathological damage were assessed to evaluate the brain pathophysiological changes. Spectrophotometric assay methods were used to determine the activities of superoxide dismutase (SOD) and glutathione‐peroxidase (GPx). Contents of malondialdehyde (MDA), the generation of reactive oxygen species (ROS) as well as respiratory control ratio and respiratory enzymes of the brain mitochondria were also determined. The results showed that cornin significantly decreased neurological deficit scores, and reduced cerebral infarct volume and degenerative neurons. Meanwhile, cornin significantly increased the brain ATP content, improved mitochondrial energy metabolism, inhibited the elevation of MDA content and ROS generation, and attenuated the decrease of SOD and GPx activities in brain mitochondria. These findings indicate that cornin has protective potential against cerebral ischemia injury and its protective effects may be due to amelioration of cerebral mitochondrial function and its antioxidant property. Copyright © 2009 John Wiley & Sons, Ltd.
Four carotenoids from Pittosporum tobira protect primary cultured rat cortical cells from glutamate‐induced toxicity
Authors: Moon Hyung‐In , Park Won‐Hwan
Published: December 2009

We observed that an aqueous extract of this medicinal plant exhibited significant neuroprotection against glutamate‐induced toxicity in primary cultured rat cortical cells from methanol extracts of the seeds of P. tobira. To further clarify the underlying neuroprotective mechanism(s) of this observed effect, we isolated and identified various active fractions and components. By using such fractionation procedures, four known carotenoids compounds – tobiraxanthins A1, A2, A3, and B – were isolated from the n‐hexane fraction of methanol extracts from the seeds of P. tobira. Among these four compounds, tobiraxanthins B exhibited significant neuroprotective activity against glutamate‐induced neurotoxicity, as indicated by a cell viability of approximately 50%, at concentrations ranging from 0.1 μM to 10 μM. These findings indicate that, the neuroprotective effects of P. tobira might be due to the inhibition of glutamate‐induced toxicity by carotenoids present in the plant. Copyright © 2009 John Wiley & Sons, Ltd.
Crocetin inhibits cell cycle G1/S transition through suppressing cyclin D1 and elevating p27kip1 in vascular smooth muscle cells
Authors: Zhou Cheng‐Hua , Xiang Min , He Shu‐Ying , Qian Zhi‐Yu
Published: December 2009

Crocetin is a natural carotenoid compound isolated from Gardenia jasminoids Ellis. Our previous study shows that crocetin inhibits angiotensin II (Ang II)‐induced vascular smooth muscle cells (VSMCs) proliferation. To further explore the mechanism by which crocetin inhibits VSMCs proliferation, in the present study we examined the effect of crocetin on cell cycle progression and cell cycle regulatory proteins. Flow cytometry analysis showed that Ang II elicited significant increase in the percentage of VSMCs in the S phase, with a concomitant decline in the percentage of VSMCs in the G0/G1 phase. However, on pretreatment of VSMCs with crocetin, the percentage of VSMCs in the S phase decreased, while that in the G0/G1 phase increased significantly. In addition, Ang II‐induced increase of cell proliferation index was also decreased by crocetin. Western blotting analysis indicated that crocetin markedly inhibited the protein expression of cyclin D1 but not cyclin E. Crocetin also increased the level of cyclin‐dependent kinase inhibitor (CDKI) p27kip1 but not CDKI p21waf1/cip1. In conclusion, our present results suggest that the inhibition of cell cycle G1/S transition in VSMCs by crocetin can be attributed, at least in part, to its suppression of cyclin D1 and elevation of CDKI p27kip1. Copyright © 2009 John Wiley & Sons, Ltd.
Pharmacokinetics of bilobalide, ginkgolide A and B after administration of three different Ginkgo biloba L. preparations in humans
Authors: Woelkart Karin , Feizlmayr Elisabeth , Dittrich Peter , Beubler Eckhard , Pinl Fritz , Suter Andy , Bauer Rudolf
Published: December 2009

A sensitive LC‐ESI‐MS method with a solid‐phase extraction was established for the determination of bilobalide, ginkgolide A and ginkgolide B in human plasma; bioavailability and pharmacokinetics of three different Ginkgo biloba L. preparations have been investigated. The preparations used in the present single‐dose pharmacokinetic study were different formulations of Ginkgo biloba L. extracts (Geriaforce™ tincture, new Ginkgo fresh plant extract tablets and EGb 761™) with various excipients. The analysis of Ginkgo terpene lactones was performed by LC‐MS on a Zorbax® SB‐C18 column. The mobile phase consisted of water + 0.1% acetic acid and methanol 68/32 (v/v) to 49/51 (v/v) at a flow rate of 200 μL/min. Bilobalide, ginkgolide A and ginkgolide B were monitored using the selected‐ion monitoring (SIM) mode at m/z of 325, 453 and 423, respectively.

The amounts of the active compounds (terpene lactones) in the administered products were in the low‐mg range per dose. The assay method was successfully applied to the study of the pharmacokinetics and bioavailability of bilobalide, gingkolide A and ginkgolide B in humans. The resulting maximum concentrations (median) of bilobalide, ginkgolide A and ginkgolide B in plasma after administration of the maximum daily dose of the different Ginkgo products were 3.53, 3.62, and 1.38 ng/mL respectively after administration of Geriaforce™ tincture; 11.68, 7.36, and 4.18 ng/mL, respectively after taking Ginkgo fresh plant extract tablets; and 26.85, 16.44, 9.99 ng/mL, respectively after administration of EGb 761™ tablets. These data are relevant to demonstrate relative bioavailabilities of different Ginkgo biloba L. preparations (Geriaforce™ tincture, new Ginkgo fresh plant extract tablets and EGb 761™). Copyright © 2009 John Wiley & Sons, Ltd.
Effect of taxifolin glycoside on atopic dermatitis‐like skin lesions in NC/Nga mice
Authors: Ahn Ji Young , Choi Sun Eun , Jeong Mi Sook , Park Kwan Hee , Moon Nam Ju , Joo Seong Soo , Lee Chung Soo , Choi Young Wook , Li Kapsok , Lee Mi‐Kyung , Lee Min Won , Seo Seong Jun
Published: December 2009

Increased levels of eosinphils, IgE, IL‐4, 5, and 13 and pro‐inflammatory factors (COX‐2, iNOS) are observed in patients with atopic dermatitis (AD). Taxifolin 3‐O‐β‐D‐glucopyranoside (TAX) from the roots of Rhododendron mucronulatum (RM) was examined to determine whether its immunomodulatory effect was applicable for treating atopic dermatitis.

A total of 7 groups of NC/Nga mice with AD were treated by topical application or intraperitoneal injection of TAX for 4 weeks. Follow‐up evaluations were done to assess the changes in clinical observations, eosinophil counts, and levels of IgE, cytokines, COX‐2 and iNOS.

In the clinical observation during the experimental period, TAX treatment significantly reduced the severity of AD‐like lesions induced in NC/Nga mice. Eosinophil and IgE levels decreased after treatment of the animals with TAX. TAX may thus be associated with improvement of eosinophil‐related allergic diseases. The expression of cytokines (IL‐4, 5 and 13) was significantly inhibited in the TAX‐treated group, suggesting that TAX might play an immunoregulatory role associated with AD. In RT‐PCR, iNOS and COX‐2 expression levels were reduced in the TAX‐treated group. In western blotting, the expression levels of iNOS and COX‐2 were also reduced in the TAX‐treated group.

These findings suggest that TAX is effective for the treatment of AD by preventing the production of inflammatory cytokines and by reducing skin inflammation. Copyright © 2009 John Wiley & Sons, Ltd.
Antihepatotoxic activity ofSaussurea lappaextract on D‐galactosamine and lipopolysaccharide‐induced hepatitis in mice
Authors: Yaeesh Sheikh , Jamal Qamar , Shah Abdul Jabbar , Gilani Anwarul Hassan
Published: December 2009

The effects of aqueous‐methanol extract ofSaussurea lappa Clarkeroot (Sl.Cr) was investigated against D‐galactosamine (D‐GalN) and lipopolysaccharide (LPS)‐induced hepatitis in mice. Co‐administration of D‐GalN (700 mg/kg) and LPS (1 μg/kg) significantly raised the plasma transaminase levels (ALT/AST) as compared to the control group (p< 0.05). Pretreatment of mice with different doses of Sl.Cr (150, 300 and 600 mg/kg) significantly prevented the D‐GalN and LPS‐induced rise in plasma levels of ALT and AST in a dose‐dependent manner (p< 0.05). Post‐treatment with Sl.Cr (600 mg/kg) significantly restricted the progression of hepatic damage induced by D‐GalN and LPS (p< 0.05). The improvement in plasma enzyme levels was further verified by histopathology of the liver, which showed improved architecture, absence of parenchyma congestion, decreased cellular swelling and apoptotic cells in treatment groups as compared to the toxin group of animals. These data indicate that the Sl.Cr exhibits hepatoprotective effect in mice and this study rationalize the traditional use of this plant in liver disorders. Copyright © 2009 John Wiley & Sons, Ltd.
Lycopene protects the structure of the small intestine against gamma‐radiation‐induced oxidative stress
Authors: Saada Helen N. , Rezk Renée G. , Eltahawy Noaman A.
Published: December 2009

The small intestine displays numerous morphological and functional alterations after exposure to ionizing radiations. Oxidative stress and changes in monoamines levels may contribute toward some of these alterations. The objective of the current work is to evaluate the efficacy of lycopene on radiation‐induced damage in the small intestine. Lycopene (5 mg/kg BW) was given to male albino rats, via gavages for 7 days before whole body exposure to gamma ray (6 Gy). Irradiated animals, sacrificed 7 days after irradiation, showed sloughing villi, ulcers, and ruptured goblet cells, shrinkage of submucosa layers, more fibers and fibroblasts. Histopathological changes were associated with a significant increase in thiobarbituric acid reactive substances (TBARS) and alteration in xanthine oxidoreductase system (XOR). In parallel, significant decreases in reduced glutathione (GSH) content, superoxide dismutase (SOD) and catalase (CAT) activities were recorded. Gamma irradiation has also induced a significant decrease in the level of monoamines: serotonin (5‐HT), dopamine (DA), norepinephrine (NE), and epinephrine (EPI) associated with an increase in monoamine‐oxidase (MAO) activity. Lycopene pretreatment has significantly improved the oxidant/antioxidant status, which was associated with significant regeneration of the small intestine, and improved monoamines levels. Based on these results, it is concluded that lycopene may protect the small intestine against radiation‐induced damage. Copyright © 2009 John Wiley & Sons, Ltd.
Output feedback stabilization for discrete singular systems with random abrupt changes
Authors: Wu Zhengguang , Su Hongye , Chu Jian
Published: December 2009

The problem of static output feedback control is investigated for discrete singular systems with Markovian jump. Two necessary and sufficient conditions for the discrete singular Markovian jump system to be regular, causal and stochastically stable are proposed in terms of linear matrix inequality (LMI) approach. Two kinds of design methods of the desired mode‐independent static output feedback controller are given. The explicit expressions for the desired controller are also given. Numerical examples are proposed to show the validness of the developed results. Copyright © 2009 John Wiley & Sons, Ltd.
A study of undergraduate physics students' understanding of heat conduction based on mental model theory and an ontology–process analysis
Authors: Chiou Guo‐Li , Anderson O. Roger
Published: December 2009

This study first used a new approach, combining students' ontological beliefs and process explanations, to represent students' mental models of heat conduction and then examined the relationships between their mental models and their predictions. Clinical interviews were conducted to probe 30 undergraduate physics students' mental models and their predictions about heat conduction. This study adopted a constant comparative method to discover patterns of the participants' responses across the various sources of data, such as verbal utterances, writings, and drawings. The results indicate that, based on the identified five process analogies for how heat is conducted and three ontological beliefs about the material basis for heat conduction, the combinations of these two aspects can better represent their mental models in terms of both the underlying mechanisms and emergent processes of heat conduction than using either alone as has sometimes been done in prior research. In addition, while a scientifically accepted mental model had a better chance to be accompanied by a correct prediction, a correct prediction might not result from a scientifically accepted mental model. However, as suggested by some cognitive psychologists, regardless of which mental models the participants possessed, they tended to automatically retrieve their learned rules or past experience, instead of manipulating their mental models, to generate predictions for the encountered problems. © 2009 Wiley Periodicals, Inc. Sci Ed 94:825–854, 2009
Numerische Schweißsimulation gekoppelt mit einem anschließenden Hämmerprozess und integrierten lokalen Ermüdungsberechnungen
Authors: Schaumann Peter , Keindorf Christian
Published: December 2009

Mit einem hochfrequenten Hämmerverfahren kann die Ermüdungsfestigkeit der Schweißnähte grundsätzlich nur gesteigert werden, wenn die Nahtübergänge dafür maßgebend sind. Zum Beispiel ergibt sich bei einseitig geschweißten Stumpfstößen keine signifikante Steigerung der Lebensdauer, weil sich die ermüdungskritische Stelle an die unbehandelte Nahtwurzel verlagert. Im vorliegenden Beitrag wird über Ergebnisse von experimentellen und numerischen Untersuchungen an un‐ und nachbehandelten Schweißverbindungen berichtet. Die Experimente erfolgten an stumpf geschweißten Stahlblechen, die anschließend an den Nahtübergängen mit einem hochfrequenten Hämmerverfahren nachbehandelt wurden. Die Schweißversuche dienten ferner als Verifikation für numerische Schweißsimulationen, die mit einem Hämmerprozess gekoppelt wurden. Ziel der Untersuchungen war es, die Effekte des Hämmerns zu erfassen, um hinsichtlich der Lebensdauer den Unterschied zwischen un‐ und nachbehandelten Schweißverbindungen numerisch aufzuzeigen. Dafür wurden das Kerbdehnungs‐ und Rissfortschrittskonzept in die Schweißsimulation implementiert, womit lokale Ermüdungsberechnungen im FE‐Modell möglich waren. Letztendlich liegen als Ergebnis nicht nur Spannungsplots, sondern auch Ermüdungsplots für die gesamte Schweißkonstruktion unter Berücksichtigung der Effekte des Schweißens und Hämmerns vor.

Numerical welding simulation coupled with a hammer peening procedure and local fatigue assessments.

Due to the post weld treatment the fatigue strength of welded joints can be enhanced in principal, if the weld toes are the most critical hot spots. But the fatigue life can not be increased significantly when the crack initiation starts at the untreated weld root. This paper provides detailed information about experimental and numerical investigations of an arc welding process followed by a process of hammer peening. The experiments were carried out on steel plates with single side butt welds. After welding the weld toes were treated by highfrequency hammer peening. However, the welding and fatigue tests were used as verifications for numerical welding simulations coupled with a hammer peening procedure and local fatigue calculations. The objective was to analyze the difference in fatigue strength between as welded and treated conditions. Therefore the change of residual stresses and notch geometry are the most important effects on the fatigue life for welded joints with and without post weld treatment. Within a fatigue tool the residual stresses and geometry of the notch can be considered in numerical simulations with local fatigue approaches. The total fatigue life was assessed by adding crack initiation life calculated with notch strain approach and crack propagation life calculated with crack propagation approach. Finally the coupled simulation provides not only stress plots but also fatigue plots for the whole welded joint under consideration of as welded and treated conditions after hammer peening.
Abminderungsfaktoren für das Biegedrillknicken von Walzprofilen – Grundsätzliches
Authors: Kindmann Rolf , Beier‐Tertel Judith
Published: December 2009

Der Nachweis ausreichender Tragfähigkeit wird bei biegedrillknickgefährdeten Trägern in der Regel mit Hilfe von Abminderungsfaktoren geführt. Die Werte nach DIN 18800‐2 und DIN EN 1993‐1‐1 (EC 3) stimmen nicht überein, sondern weisen bereichsweise große Unterschiede auf. Zur Klärung des Sachverhalts werden für ausgewählte Basissysteme genaue Abminderungsfaktoren nach der Fließzonentheorie berechnet. Dabei zeigt sich, dass vergleichbare Werte in Abhängigkeit von der Querschnittsgeometrie um bis zu 32 % streuen. Als Parameter, mit dem die Profilabhängigkeit erfasst werden kann, wird das Verhältnis ly/IT identifiziert. Auf Grundlage dieser Erkenntnisse wird die Genauigkeit der Abminderungsfaktoren in den genannten Vorschriften beurteilt und festgestellt, dass eine Anpassung an den aktuellen Erkenntnisstand erforderlich ist.

Reduction factors for lateral torsional buckling of hot rolled profiles – fundamentals.

The resistance of members endangered by lateral torsional buckling is usually verified using reduction factors. The values of DIN 18800‐2 and DIN EN 1993‐1‐1 (EC 3) do not match and partly show big differences. For a clarification of this issue the reduction factors of selected basic structural systems are being determined according to the plastic zones theory. It can be recognized that corresponding values differ up to 32 % depending on the cross‐section geometry. The ratio ly/IT is being identified as a parameter covering the dependency of the crosssection. On this basis the reduction factor accuracy of the standards mentioned previously is being analysed with the conclusion, that an adjustment to the current state of knowledge is necessary.
Einstellbare Kranbahnkonsole aus Stahlblech zum Anbau an Stahlbeton‐Fertigteilstützen
Authors: Bube Eckhard , Hardt Andreas
Published: December 2009

Der einwandfreie Betrieb einer Krananlage ist abhängig von der Einhaltung enger Toleranzgrenzen. Herkömmliche Stahlbetonkonsolen erlauben keinen wirtschaftlichen Ausgleich der Hochbau‐ und Fertigungstoleranzen. Qualitätsmängel, Mehraufwendungen und Terminverzug durch Montageprobleme sind die Folge. Die neuentwickelte Stahlkonsole ermöglicht eine bequeme Einstellbarkeit und bietet eine wirtschaftliche Lösung für den Tragwerksplaner, den Hersteller der Stahlbetonkonstruktion und den Kranbahnlieferanten. Eine Reihe mit statischen und dynamischen Versuchen bestätigt die Tragfähigkeit und die Gebrauchstauglichkeit der neuen Stahlkonsole.

Adjustable crane way bracket made of steel plates for fastening to a concrete support.

The operation of a crane system depends on the realisation of the crane runway tolerance. Common concrete brackets do not allow an economical compensation of building and manufacturing tolerances. The result is a lack of quality, additional fitting work and time delay. The new designed steel bracket allows a comfortable adjustability and offers an innovative solution for engineering, manufacturing and assembly. Several tests under static and dynamic conditions confirm the load capacity and the service fitness of the new steel bracket.
Vergleichende Untersuchungen zur Windbelastung auf freistehende Telekomunikationsmasten nach DIN 4131 und Eurocode 3
Authors: Vayas Ioannis , Dasiou Maria‐Eleni , Efthymiou Evangelos
Published: December 2009

Wind stellt die wichtigste Einwirkung bei der Bemessung freistehender Gittermasten aus Stahl dar. Nach Einführung der Eurocodes im März 2010 soll die Windbelastung auf Masten nach Eurocode bestimmt werden, anstelle der bis jetzt auch in Griechenland gültigen Norm DIN 4131. Telekommunikationsmasten werden mit immer neuen Antennen bestückt, so dass die Standsicherheit ständig nach den gültigen Normen neu geprüft werden muss. So ergibt sich die Notwendigkeit einer Untersuchung, ob die neue Norm günstige oder ungünstige Ergebnisse liefert. Im folgenden Beitrag werden Ergebnisse vergleichender Untersuchungen zur Windbelastung und ihrer Auswirkung nach DIN sowie nach den Eurocodes dargestellt. Es zeigt sich, dass die Be‐messungskräfte nach Eurocode in Abhängigkeit von den Eingangsdaten in Bezug auf die Topographie, der Zuverlässigkeitsklasse usw. sowohl kleiner als auch größer sein können als nach DIN.

Comparative study of wind loading on telecommunication masts according to DIN 4131 and Eurocode 3.

Wind is the principal action for the design of self‐supporting lattice steel masts. After the introduction of the Eurocodes on March 2010, wind loading shall be determined according to Eurocode instead of DIN 4131, applicable also in Greece. New antennas are constantly placed on masts, which are used for telecommunication purposes, so that new strength and stability verifications according to the valid Codes are continuously needed. This paper presents comparative studies on the wind loading and their effects according to DIN and the Eurocodes. It is shown that the design forces according to Eurocode, dependent on the importing data related to the topography, the reliability class etc., can be smaller or larger than the corresponding ones resulting from DIN.
Brandschutz für die Hallen der Neuen Messe in Stuttgart
Authors: Brux Gunther
Published: December 2009

Die neun Hallen der Neuen Messe in Stuttgart mit insgesamt über 100000 m2 Ausstellungsfläche haben weitgespannte Hängedächer und F90‐feuerbeständige Stahlkonstruktionen. Dabei bestehen Druck‐ und Zugstützen sowie Riegel aus betongefüllten Rohren mit und ohne Stahlkern sowie teilweise mit Beschichtung mit Dämmschichtbildnern. Diese Mischform des baulichen Brandschutzes erforderte besondere Voruntersuchungen.
Evaluation of the Efficiency of the Macrolactonization Using MNBA in the Synthesis of Erythromycin A Aglycon
Authors: Shiina Isamu , Katoh Takashi , Nagai Shunsuke , Hashizume Minako
Published: December 2009

Various intermediates for the synthesis of erythronolide A, an aglycon of erythromycin A, are prepared from the corresponding seco‐acids using 2‐methyl‐6‐nitrobenzoic anhydride (MNBA) in the presence of 4‐(dimethylamino)pyridine (DMAP) with or without triethylamine. The efficiency of the MNBA lactonization is assessed by studying this method and comparing the results with those of the other established macrocyclization protocols. It has been finally concluded that (i) the conformationally appropriate substrate for the monomeric cyclization gave the desired lactone in excellent yield under mild reaction conditions in the presence of MNBA and DMAP, (ii) the highly‐strained substrate for the cyclization also afforded the monomeric lactone in relatively good yield at 100°C in toluene, and (iii) the seco‐acid having stable linear conformation, which preferred dimerizing more than forming the monomeric lactone, provided the corresponding diolide in high yield with the constant ratio of the monomer to dimeric lactone (approximately 1/5). © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 305–320; 2009: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900017
Therapeutic Efficacy Comparison of Two Surgical Procedures to Treat Middle Thoracic Esophageal Carcinoma
Authors: Yu Yang , Wang Zhou , Liu Xiang‐Yan , Zhu Xiao‐Feng , Chen Qing‐Fu
Published: December 2009

Background

The aim of this study was to evaluate the therapeutic efficacy of two surgical procedures used to treat middle thoracic esophageal squamous cell carcinoma and compare the results.

Methods

A total of 167 patients with middle thoracic esophageal squamous cell carcinoma were included in the study, including 102 patients who underwent Ivor‐Lewis esophagectomy and another 65 who underwent dual‐incision esophagectomy through the left chest and neck (Dual‐incision). The Kaplan–Meier method was used to calculate the survival rate, and Cox regression analysis was performed to identify prognostic risk factors.

Results

Perioperative complications occurred in 35 patients (21%). The incidence rate of recurrent laryngeal nerve injury and anastomotic leakage was higher in the Dual‐incision group (p < 0.05), and the incidence rate of gastric retention was higher in the Ivor‐Lewis group. However, there were no statistically significant differences. The 3‐year local recurrence rate was 37.3% in the Ivor‐Lewis group and 40% in the Dual‐incision group (p > 0.05). The overall 5‐year survival rate was 34.6%; the rates of the Ivor‐Lewis group and the Dual‐incision group were 36.0 and 32.3%, respectively (p > 0.05). The Cox analysis indicated that the pTNM staging was an independent prognostic risk factor (p = 0.00, hazard ratio = 2.69).

Conclusions

Both Ivor‐Lewis esophagectomy and Dual‐incision esophagectomy through the left chest and neck are options for treating middle thoracic esophageal squamous cell carcinoma. It is suggested that a patient’s individual condition be taken into account when choosing the operative approach.
Antibiotic Therapy Versus Appendectomy for Acute Appendicitis: A Meta‐Analysis
Authors: Varadhan Krishna K. , Humes David J. , Neal Keith R. , Lobo Dileep N.
Published: December 2009

Background

Antibiotic treatment has been shown to be effective in treating selected patients with acute appendicitis, and three randomized controlled trials (RCTs) have compared the efficacy of antibiotic therapy alone with that of surgery for acute appendicitis. The purpose of this meta‐analysis of RCTs was to assess the outcomes with these two therapeutic modalities.

Methods

All RCTs comparing antibiotic therapy alone with surgery in patients over 18 years of age with suspected acute appendicitis were included. Patients with suspected perforated appendix or peritonitis, and those with an allergy to antibiotics had been excluded in the RCTs. The outcome measures studied were complications, length of hospital stay, and readmissions.

Results

Meta‐analysis of RCTs of antibiotic therapy versus surgery showed a trend toward a reduced risk of complications in the antibiotic‐treated group [RR (95%CI): 0.43 (0.16, 1.18) p = 0.10], without prolonging the length of hospital stay [mean difference (inverse variance, random, 95% CI): 0.11 (−0.22, 0.43) p = 0.53]. Of the 350 patients randomized to the antibiotic group, 238 (68%) were treated successfully with antibiotics alone and 38 (15%) were readmitted. The remaining 112 (32%) patients randomized to antibiotic therapy crossed over to surgery for a variety of reasons. At 1 year, 200 patients in the antibiotic group remained asymptomatic.

Conclusions

This meta‐analysis suggests that although antibiotics may be used as primary treatment for selected patients with suspected uncomplicated appendicitis, this is unlikely to supersede appendectomy at present. Selection bias and crossover to surgery in the RCTs suggest that appendectomy is still the gold standard therapy for acute appendicitis.