bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pd/C‐Catalyzed Cyanation of Aryl Halides in Aqueous PEG
Authors: Chen Gong , Weng Jiang , Zheng Zhanchao , Zhu Xinhai , Cai Yaoyao , Cai Jiwen , Wan Yiqian 
Published: May 2008

AbstractAn environmentally friendly Pd/C–PEG–H2O system was developed for the cyanation of aryl halides under microwave irradiation. A wide range of aryl bromides, iodides, and some activated chlorides were demonstrated to be cyanated smoothly by using nontoxic K4[Fe(CN)6]·3H2O as the cyanide source. There is no phosphorus‐ or nitrogen‐containing ligand or solvent involved. Moreover, this reaction can becarried out without the protection of inert atmosphere. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Optically Active γ‐Hydroxy Sulfone Julia Reagents for the Synthesis of Peptidyl Olefin Peptidomimetics
Authors: Mirilashvili Sima , Chasid‐Rubinstein Naama , Albeck Amnon 
Published: May 2008

AbstractPeptidyl olefin peptidomimetics serve as biologically active compounds or as intermediates for other peptidyl isosteres. We developed a chemoenzymatic stereoselective approach to optically active γ‐hydroxy sulfones to be assembled into peptidyl olefins by the Julia reaction. Key enzymatic hydrolysis of prochiral diesters to the corresponding hydroxy esters introduces optical activity. The sequence of the subsequent chemical reactions, either protection–hydrolysis–functionalization or functionalization–hydrolysis–protection, determines the absolute stereochemistry of the final sulfone building block.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Fluorinated Johnson Reagent for Transfer‐Trifluoromethylation to Carbon Nucleophiles
Authors: Noritake Shun , Shibata Norio , Nakamura Shuichi , Toru Takeshi , Shiro Motoo 
Published: May 2008

AbstractA novel reagent, [(oxido)phenyl(trifluoromethyl)‐λ4‐sulfanylidene]dimethylammonium tetrafluoroborate has been developed for the electrophilic trifluoromethylation of carbon nucleophiles. The reagent was designed as a trifluorinated version of a Johnson‐type methyl‐transfer reagent. The firstexample of vinylogous trifluoromethylation of dicyanoalkylidenes is also demonstrated.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Production, characterization, and efficient transfection of highly pure oligodendrocyte precursor cultures from mouse embryonic neural progenitors
Authors: Pedraza Carlos E. , Monk Raymond , Lei Junying , Hao Qi , Macklin Wendy B. 
Published: May 2008

AbstractMuch current knowledge of oligodendrocyte biology, the myelin‐forming cells in the central nervous system, comes from cell culture studies mainly from postnatal rat tissue but mouse cells have been much more difficult to produce in large quantities. We have developed a high yield protocol for production of oligodendrocyte precursor cells from mouse embryonic neural progenitors grown as neurospheres. Neurospheres can be maintained and expanded for long periods in culture in the presence of epidermal growth factor (EGF). When floating neurospheres were plated on substrate‐coated dishes in media supplemented with platelet derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), the spheres attached and generated migrating cells that were predominantly oligodendrocyte‐lineage cells. Furthermore, cells in spheres could be shifted to the oligodendrocyte phenotype prior to plating on substrate, by incubation in suspension with PDGF/bFGF. Single cell suspensions plated after dissociation of either EGF‐treated neurospheres or PDGF/bFGF‐treated oligospheres had the bipolar, elongated morphology characteristic of oligodendrocyte precursor cells. mRNA and protein expression analysis of the cells generated by this method confirmed their oligodendrocyte lineage. Oligodendrocyte precursors generated by this method matured in response to ciliary neurotrophic factor treatment, producing cells with multiple processes and myelin‐like membranes. The most important aspect of this protocol is the ability to generate very high numbers of relatively pure mouse oligodendrocyte progenitor cells, which can be easily transfected. These studies open up many kinds of investigations on transgenic and mutant mouse oligodendrocytes, thereby providing a valuable tool to study oligodendrocyte biology and development. © 2008 Wiley‐Liss, Inc.
The role of PGP9.5 as a tumor suppressor gene in human cancer
Authors: Tokumaru Yutaka , Yamashita Keishi , Kim Myoung Sook , Park Hannah L. , Osada Motonobu , Mori Masaki , Sidransky David 
Published: May 2008

AbstractPGP9.5 is a controversial molecule from an oncologic point of view. We recently identified frequent methylation of PGP9.5 gene exclusively in primary head and neck squamous cell carcinoma (HNSCC), suggesting that it could be a tumor suppressor gene. On the other hand, PGP9.5 was reported to be overexpressed in a subset of human cancers presumably due to intrinsic oncogenic properties or as a result of transformation. To demonstrate that PGP9.5 possesses tumor suppressive activity, we examined forced expression by stable transfection of PGP9.5 in 4 HNSCC cell lines. Although all 4 cell lines demonstrated reduced log growth rates in culture after transfection, only 2 cell lines with wild type p53 (011, 022) demonstrated decreased growth in soft agar. In 2 cell lines with mutant p53 (013, 019), we observed no altered growth in soft agar and increased sensitivity to UV irradiation. We then tested for and found a high frequency of promoter methylation in a larger panel of primary tumors including HNSCC, esophageal SCC, gastric, lung, prostate and hepatocellular carcinoma. Our data support the notion that PGP9.5 is a tumor suppressor gene that is inactivated by promoter methylation or gene deletion in several types of human cancers. © 2008 Wiley‐Liss, Inc.
Corn yield response to irrigation interval and the resultant savings in water and other overheads
Authors: Dioudis Paschalis S. , Filintas Agathos T. , Papadopoulos Aristotelis H. 
Published: May 2008

AbstractThe aim of this project was to conduct research into the effect of irrigation interval, using drip irrigation, on the depletion of available soil moisture and on corn yield, and the possible savings it might bring about in water, manpower, energy and other overheads. The experiments were carried out between 2000 and 2001 in the plain of Thessaly, central Greece. The experimental field had a complete randomized block design and consisted of three treatments (i.e. irrigation every 2, 5 and 9 days) for four replicates. Daily measurements were taken of the soil moisture content using the time domain reflectrometry (TDR) method and the depletion of available soil moisture was calculated. The amount of water used in each irrigation session was equal to the cumulative evapotranspiration between two successive irrigation sessions as measured using evaporation pan type A.Results showed that irrigation could be carried out every nine days instead of every two or even five days, thus bringing about substantial savings in the consumption of water. In addition, other overheads such as manpower, energy, etc. could be cut down with no statistically significant difference in crop yield. Copyright © 2008 John Wiley & Sons, Ltd.
Disjoint T‐paths in tough graphs
Authors: Kaiser Tomáš 
Published: May 2008

AbstractLet G be a graph and T a set of vertices. A T‐path in G is a path that begins and ends in T, and none of its internal vertices are contained in T. We define a T‐path covering to be a union of vertex‐disjoint T‐paths spanning all of T. Concentrating on graphs that are tough (the removal of any nonempty set X of vertices yields at most |X| components), we completely characterize the edges that are contained in some T‐path covering. Our main tool is Mader's ${\cal S}$‐paths theorem. A corollary of our result is that each edge of a k‐regular k‐edge‐connected graph (k ≥ 2) is contained in a T‐path covering. This is, in a sense, a best possible counterpart of the result of Plesník that every edge of a k‐regular (k‐1)‐edge‐connected graph of even order is contained in a 1‐factor. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 1–10, 2008
Daily performance at work: feeling recovered in the morning as a predictor of day‐level job performance
Authors: Binnewies Carmen , Sonnentag Sabine , Mojza Eva J. 
Published: May 2008

AbstractThis study examined the state of being recovered in the morning (i.e., feeling physically and mentally refreshed) as a predictor of daily job performance and daily compensatory effort at work. Ninety‐nine employees from public service organizations completed a general survey and two daily surveys on pocket computers over the course of one workweek. Hierarchical linear modeling showed that being recovered in the morning was positively related to daily task performance, personal initiative, and organizational citizenship behavior and negatively related to daily compensatory effort at work. Relationships between the state of being recovered and day‐specific job performance were moderated by job control. For persons with a high level of job control, the relationship between being recovered and daily performance was stronger. Copyright © 2008 John Wiley & Sons, Ltd.
Corrosion behaviour of boiler steels, coatings and welds in flue gas environments
Authors: Kalivodová J. , Baxter D. , Schütze M. , Rohr V. 
Published: May 2008

AbstractIn recent years there has been a steadily increasing focus on energy efficiency as a means to reduce the negative impact of human activity on climate, and in particular the effect that industrial emissions have on changes in the climate, specifically global warming. As far as power generation is concerned, emissions can be limited by maximizing energy efficiency while ensuring high levels of plant reliability. This paper reports on materials development work involving coated heat exchange alloys and the effect of welding of the coated alloys, simulating fabrication, on subsequent corrosion performance under laboratory conditions. Samples of the common boiler steels P91 (9% Cr) and HCM12A (12% Cr) were treated by chemical vapour deposition (CVD) in a pack cementation process to produce Al‐rich coatings up to 100 µm thick. The samples were machined to give bevelled edges for welding. Welding was carried out using commonly available alloy 625 filler metal. It was found that sound weldments could readily be produced provided that care was taken to limit the heat input during the welding process. Excessive heat input could lead to cracking, but more importantly to dilution of Al in the coating adjacent to the weldment and in segregation of elements (Mo and Nb) in the weldment itself. Both dilution and segregation effects led to decreased corrosion resistance.
Corrosion of alloys and their diffusion aluminide coatings by KCl:K2SO4 deposits at 650 °C in air
Authors: Vokál V. , Rohr V. , Pomeroy M. J. , Schütze M. 
Published: May 2008

AbstractP91 ferritic‐martensitic steel, 17Cr–13Ni and alloy 800 austenitic stainless steels and Inconel 617 alloy have been aluminised to form Fe2Al5, (Fe,Ni)Al and Ni2Al3 aluminide coatings. These alloys and their corresponding coatings were subjected to corrosion in air by 50:50 mol/mol K2SO4/KCl deposits at 650 °C for 300 h. With the exception of the Inconel 617 alloy, significant metal losses (>180 µm) were recorded. These losses were planar for P91 alloy but involved internal corrosion for the two austenitic steels. The (Fe,Ni)Al and NiAl coatings on the austenitic steels and the Inconel 617 alloy were significantly corroded via intergranular and internal chloridation–sulphidation–oxidation. In contrast, the Fe2Al5 coating on the P91 alloy coating was virtually unattacked. For the alloys, the relative extents of corrosion damage can be explained in terms of the stability and volatility of metal chlorides formed. For the coatings, STEM/EDS analyses enable clear linkages to be made between the presence and number of Cr‐rich particles on coating grain boundaries and the corrosion damage observed for the coatings.
Oxide scale formation on Al containing Ni–Cr‐based high temperature alloys during application as flame tube material in recirculation oil burners
Authors: Ackermann H. , Teneva‐Kosseva G. , Köhne H. , Lucka K. , Richter S. , Mayer J. 
Published: May 2008

AbstractThe flame tube is an important functional component of burners using the concept of the flame tube stabilised combustion. Under typical combustion conditions the material of the flame tube is exposed to high temperatures (≥900 °C) and to corrosion attack by the combustion gases. Furthermore as the burners are generally operated intermittently, the material suffers from extreme temperature and atmosphere changes. For flame tubes, a lifetime of approximately 8000 h is desired. Predominantly metallic high temperature materials are used. The scope of the present work was to test—under application conditions and for maximum material temperatures exceeding 900 °C—alternative high temperature alloys for use as tube material. The corrosion resistance of the austenitic Ni–Cr‐based alloys (601, 602 CA, 617 and 693) has been investigated in a burner rig at maximum material temperatures of 950 and 1000 °C and with exposure times from 50 to 3000 h. The chromium content of the alloys was between 20 and 30 wt% and that of aluminium between 1 and 3.4 wt%. Metallographic cross‐sections of samples of the alloys were analysed by electron microprobe yielding information about the microstructure and composition of the oxides in the surface zone and variations during exposure time. This study focuses on the observed specific effects of the alloying element aluminium on the development of the oxide scale and on the lifetime of the alloys. At the alloy surface after 500 h exposure time a chromium oxide scale had formed with aluminium oxides underneath predominantly along grain boundaries. For the alloys with the lower aluminium content, the aluminium oxides built up an open network but not a closed layer. For the alloy with the highest aluminium content (alloy 693) after 50 h two different characteristic microstructures at the surface were found. In one case, the grains at the surface were covered with chromium oxide on top and the remaining grain surface was completely enclosed by aluminium oxides. In the other case, the aluminium oxide formed a thin layer directly below the chromium oxide scale. After 500 h exposure time, a significantly thinner chromium oxide scale and massive internal chromium oxides were observed. Catastrophic corrosion, formation of internal oxides and aluminium nitrides started even after 500 h. It will be demonstrated that the early breakdown of alloy 693 is linked to the aluminium oxides which act as a barrier constricting the diffusion of chromium from the alloy matrix towards the surface. Under the conditions of extreme temperature changes given in the burner the aluminium oxide layer on its part did not provide corrosion protection.
Development of thermal sprayed layers for high temperature areas in waste incineration plants
Authors: Bendix D. , Tegeder G. , Crimmann P. , Metschke J. , Faulstich M. 
Published: May 2008

AbstractCorrosion and wear in the hot gas area of thermal energy plants are severe problems, which often cause premature damage of components. In general, the most components of plants are made of materials, which are not stable under corrosive conditions. For corrosion protection (and also wear protection) and lifetime extension of these components, coatings with more resistant materials are applied. Because of the high concentration of corrosive species and the alternating composition of the atmosphere near to the components, the waste incineration plant is the “worst case” of high temperature corrosion. Nowadays, the most usual coating process to protect pipes in the waste incineration plants is cladding. In the last few years, alternative processes are under investigation because cladding is very cost‐intensive. The specific costs of thermal spraying are much lower than those of cladding. In addition, the coating by thermal spraying reduces the risk of the dilution of substrate and coating material, different materials can be combined (e.g. metal alloys, ceramics) and the thickness of the layer for an acceptable resistance according to corrosion and wear can be drastically reduced. Thermal spraying has the potential to create cost‐efficient coatings to protect components in the critical zones of incineration plants.Since many years, ATZ Entwicklungszentrum is involved in the development and/or advancement of materials, technologies and applications of thermal spraying for corrosion and/or wear protection in thermal energy plants. The main focuses of the investigations are layers for components in high temperature areas of waste incineration plants. On the basis of the present results, different coatings (metal alloys, ceramics) and different spray technologies (e.g. HVOF, APS) have been tested by different strategies (corrosion tests under laboratory scale, air cooled material probes inside the hot gas area of an incineration plant and coated pipes in operation as part of the superheater of incineration plants). This paper will give an overview about the current results of these corrosion tests, in which the focus are the investigations with material probes. First results showed that with the combination of different thermal sprayed layers a significant corrosion protection can be achieved.
Void formation and filling under alumina scales formed on Fe–20Cr–5Al based alloys and coatings, oxidised at temperatures up to 1200 °C
Authors: Potter D. J. , Al‐Badairy H. , Tatlock G. J. , Bennett M. J. 
Published: May 2008

AbstractDuring the oxidation, in laboratory air, of thin foils of Fe–20Cr–5Al based alloys, voids were formed in the substrate beneath the outer protective alumina scale after times varying from 50 h at 900 °C to 10 min at 1200 °C. Once the substrate aluminium level had dropped below a critical value (≤0.5 wt%), it no longer sustained the alumina scale formation and, as a consequence, continuing oxidation resulted in the initiation and development of a Cr‐rich oxide sub‐layer formation. At the lower temperatures, the voids filled with chromia leading to a scallop‐shaped inner layer beneath the alumina scale. In contrast, at higher temperatures, the Cr‐rich sub‐scale layer was continuous. If the Fe–20Cr–5Al based alloys are deposited as coatings, for example as a compliant layer onto a stronger substrate, there is a risk that other elements (such as silicon) from the substrate may diffuse through the coating and influence the subsequent oxidation behaviour of the coating. In order to simulate this, sandwiches of Fe–Cr–Al and a silicon rich substrate were fabricated and tested over a range of oxidation temperatures. It was then found that the silicon did indeed diffuse through the Fe–Cr–Al layer and change the oxidation mechanism. The voids formed under the alumina were now found to contain silicon oxide rather than chromia, but the void filling mechanism also appeared to be different. With chromia filled voids the filling commenced from the alumina scale, with the oxide growing inwards, while the silica rich regions grew outwards into the voids from the substrate. Scanning electron microscopy and EDX analysis were used to follow these changes and those in other more complex situations. Detailed mechanisms for void and chromia sub‐scale formation and development will be discussed in the paper.
Influence of a TiO2 surface treatment on the growth and adhesion of alumina scales on FeCrAl alloys
Authors: Galerie A. , N'Dah E. , Wouters Y. , Roussel‐Dherbey F. 
Published: May 2008

AbstractDeposits of TiO2 on FeCrAl alloys were obtained by surface TiO2 slurry application or by immersion of samples in tetraisopropylorthotitanate (TIPT) solution followed by air dry which gave the thinnest coatings. Isothermal oxidation of treated samples showed strong modification compared to non‐treated ones, particularly in the temperature range of 850–925 °C where parabolic rate constants rapidly decreased when alloys were TiO2 treated. SEM surface observation, X‐ray diffraction and ruby fluorescence showed that the presence of TiO2 promoted the formation of α‐Al2O3 whereas non‐treated samples exhibited large amounts of transition aluminas. An interesting effect of the rapid change from metastable to stable α‐alumina was a strong increase of scale adhesion, determined by tensile testing, from 300–400 to 2000 J/m2 for scales grown at 850 °C on Aluchrom YHfAl. This was explained not only by the change from outward to mainly inward growth but also by the volume reduction at the transition to alpha transformation.
“Sandglass”‐Shaped Self‐Assembly of Coil–rod–coil Triblock Copolymer Containing Rigid Aniline‐Pentamer
Authors: Huang Lihong , Hu Jun , Lang Le , Zhuang Xiuli , Chen Xuesi , Wei Yen , Jing Xiabin 
Published: May 2008

AbstractThe amphiphilic PEG1 500‐b‐EM AP‐b‐PEG1 500 (EM PAP) triblock copolymer of poly(ethylene glycol) (PEG) and emeraldine aniline‐pentamer (EM AP) in its concentrated solution can self‐assemble into a special shape like “sandglass”, as observed by transmission electron microscopy (TEM), field emission scanning electron microscopy (ESEM) and atomic force microscopy (AFM). This “sandglass”‐shaped assembly is composed of several “rods” aggregated in the middle, with every “rod” being about 8 µm in length and 300 nm in diameter. We conclude that the special “sandglass”‐shaped assembly may come into being because of the inducement effect of the crystallization of EM AP segments, by studying electron diffraction (ED) results and wide‐angle X‐ray diffusion (WAXD) characterization of the EM PAP triblock copolymer.magnified image
A splitting positive definite mixed element method for second‐order hyperbolic equations
Authors: Zhang Jiansong , Yang Danping 
Published: May 2008

AbstractIn this article, we establish a new mixed finite element procedure, in which the mixed element system is symmetric positive definite, to solve the second‐order hyperbolic equations. The convergence of the mixed element methods with continuous‐ and discrete‐time scheme is proved. And the corresponding error estimates are given. Finally some numerical results are presented. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Time, temperature, and strain effects on viscoelastic Poisson's ratio of epoxy resins
Authors: Pandini Stefano , Pegoretti Alessandro 
Published: May 2008

AbstractPoisson's ratio of polymeric materials, although generally assumed as a constant, is known to display a viscoelastic dependence on time, temperature, and strain. This article investigates the phenomenology of this dependence on two crosslinked epoxy systems with different glass transition temperatures. Poisson's ratio measurements are performed by contact extensometers simultaneously measuring the axial and transverse deformations under two different tensile testing conditions: (i) constant deformation rate, in which the effects of strain, strain rate, and temperature are highlighted; (ii) stress relaxation (or constant deformation), where the dependence of Poisson's ratio on time is studied at various strain levels. The viscoelastic Poisson's ratio increases as strain, temperature, and time increases, with trends markedly depending on the materials glass transition. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.