bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Synthesis of Push‐Pull Pyrroles, Their Oxidation to Stable 3H‐Pyrroles and an Unexpected Anellation Reaction
Authors: Buehrdel Gunther , Beckert Rainer , Herzigova Petra , Petrlikova Eva , Schuch Dirk , Birckner Eckhard , Goerls Helmar 
Published: May 2009

AbstractA new synthesis of push‐pull pyrroles of type 5 was developed starting from bis(imidoyl chlorides) 1 and various iminodiacetic acid derivatives 3. The use of appropriate N‐trifluoroacetyl residues as protecting/activating group proved to be the method of choice for the straightforward preparation of the 3,4‐diarylamino‐1H‐pyrroles 5. When benzothiazole substructures are present in 2,5‐position of heterocycles 5, a two‐electron oxidation leads to 3H‐pyrroles of type 6 in excellent yields. However, in the case of cyano or ester groups, a further oxidative process immediately led to the new 3H‐pyrrolo[3,4‐b]quinoxalines 7 via intramolecular ring anellation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Mutagenic potency of MMS‐induced 1meA/3meC lesions in E. coli
Authors: Nieminuszczy Jadwiga , Mielecki Damian , Sikora Anna , Wrzesiński Michał , Chojnacka Aleksandra , Krwawicz Joanna , Janion Celina , Grzesiuk Elżbieta 
Published: May 2009

AbstractThe mutagenic activity of MMS in E. coli depends on the susceptibility of DNA bases to methylation and their repair by cellular defense systems. Among the lesions in methylated DNA is 1meA/3meC, which is recently recognized as being mutagenic. In this report, special attention is focused on the mutagenic properties of 1meA/3meC which, by the activity of AlkB‐dioxygenase, are quickly and efficiently converted to natural A/C bases in the DNA of E. coli alkB+ strains, preventing 1meA/3meC‐induced mutations. We have found that in the absence of AlkB‐mediated repair, MMS treatment results in an increased frequency of four types of base substitutions: GC→CG, GC→TA, AT→CG, and AT→TA, whereas overproduction of PolV in CC101–106 alkB−/pRW134 strains leads to a markedly elevated level of GC→TA, GC→CG, and AT→TA transversions. It has been observed that in the case of AB1157 alkB− strains, the MMS‐induced and 1meA/3meC‐dependent argE3→Arg+ reversion occurs efficiently, whereas lacZ−→ Lac+ reversion in a set of CC101–106 alkB− strains occurs with much lower frequency. We considered several reasons for this discrepancy, namely, the possible variance in the level of the PolV activity, the effect of the PolIV contents that is higher in CC101–106 than in AB1157 strains and the different genetic cell backgrounds in CC101–106 alkB− and AB1157 alkB− strains, respectively. We postulate that the difference in the number of targets undergoing mutation and different reactivity of MMS with ssDNA and dsDNA are responsible for the high (argE3→Arg+) and low (lacZ− → Lac+) frequency of MMS—induced mutations. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Reform of the East China power market and assessment of the market structure
Authors: Meng Qian , Haubrich Hans‐Jürgen , Tersteegen Bernd 
Published: May 2009

AbstractThe liberalization of the power market in East China has made much progress. From May 2004 until today, the power market in East China stepped into the stages of simulation and trial operation. In this paper, the market design is introduced and the market structure is assessed by aspects of horizontal concentration, vertical integration, and market barriers. Copyright © 2009 John Wiley & Sons, Ltd.
Electricity pricing and market power—evidence from Germany
Authors: Janssen M. , Wobben M. 
Published: May 2009

AbstractThe aim of this paper is to develop a methodology for measuring the exercise of potential market power in liberalized electricity markets. We therefore investigate producer behavior in the context of electricity pricing with respect to fundamental time‐dependent marginal cost (TMC), i.e., CO2‐ and fuel cost. In doing so, we do not—in contrast to most current approaches to market power investigation—rely on an estimate of the entire generation cost, which inevitably suffers from the lack of appropriate available data. Applying an analytical model of a day‐ahead electricity market, we derive work‐on rates, which provide information about the impact of TMC variations on electricity prices in the market constellations of perfect competition, quasi‐monopoly, and monopoly. Comparing these model‐based work‐on rates with actual work‐on rates, estimated by an adjusted first‐differences regression model of German power prices on the cost for hard coal, natural gas, and emission allowances, we find evidence of the exercise of market power in the period 2006–2008. However, our results reveal that German market competitiveness increases marginally. We confirm our results by simulating a TMC‐driven diffusion model of futures power prices estimated by maximum‐likelihood. Copyright © 2009 John Wiley & Sons, Ltd.
Algorithmic challenges and current problems in market coupling regimes
Authors: Tersteegen Bernd , Schröders Christian , Stein Sebastian , Haubrich Hans‐Jürgen 
Published: May 2009

AbstractIncreasing cross‐border trade at European borders has lead to the necessity of an efficient allocation of scarce cross‐border capacities. Explicit auctions used to be the commonly applied auction method in the past at most borders, but due to the separation of the trade of electrical energy and the allocation of cross‐border capacity, market inefficiencies arise. As a consequence, a trend toward a market coupling, which combines the trade of electrical energy with the allocation of cross‐border capacity, can be observed across Europe. The most convincing approach to solve the complex optimization task associated with market couplings solves the problem by a maximization of the system‐wide welfare based on a closed‐form optimization. Practical experience shows that problems remain with such an approach. This paper thoroughly analyzes problems that may occur in market coupling regimes with a closed‐form optimization. In this paper an extension of formerly presented formulations of the optimization problem is presented, which avoids the described problems. The extended formulation still assures practically feasible calculation times of far less than 10 minutes even for systems with up to 12 market areas. Further, a fair and transparent approach to determine feasible market clearing prices not neglecting the time and market coupling relationship between prices is shown in this paper and it is demonstrated that this approach does not lead to practically infeasible calculation times. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of manure and mineral fertilisation on pepper nutritional quality
Authors: Flores Pilar , Hellin Pilar , Fenoll Jose 
Published: May 2009

AbstractBACKGROUND: The influence of farming systems on fruit quality remains controversial and the different aspects associated with each agricultural management system need to be studied separately to elucidate any specific effect on fruit quality. To this end, a greenhouse experiment was conducted to examine the effect of the usual fertilisation guidelines for pepper cultivation on the nutritional quality of fruits (sugars, vitamin C, total phenolic compounds, chlorophylls, total carotenoids and antioxidant activities in the hydrophilic (HAA) and lipophilic (LAA) fractions). Treatments included manure amendment combined with synthetic fertiliser applied at the rates recommended for organic (T1), low‐input (T2) and conventional (T3) practices.RESULTS: Pepper composition was not affected by increasing mineral fertilisation. In addition, treatment had no significant effect on HAA or LAA. The antioxidant activity of both the hydrophilic and lipophilic fractions increased from the green to the red stage of ripening. HAA contributed about 80% of the total antioxidant activity.CONCLUSION: Pepper response to mineral fertilisation seems to be less pronounced than that of other fruits, since antioxidant concentrations did not increase with increasing fertiliser application. Antioxidant activity in pepper was mainly linked to hydrophilic compounds (vitamin C and phenolic compounds). Ripening was the most important factor determining the fruit antioxidant composition. Copyright © 2009 Society of Chemical Industry
Inhibition action of tween‐80 on the corrosion of cold rolled steel in sulfuric acid
Authors: Li X. H. , Deng S. D. , Fu H. , Mu G. N. 
Published: May 2009

AbstractThe inhibition action of a nonionic surfactant of tween‐80 on the corrosion of cold rolled steel (CRS) in sulfuric acid (H2SO4) has been investigated by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the CRS surface conditions. The results show that tween‐80 is a good inhibitor in 1.0 M H2SO4, and its adsorption obeys Langmuir adsorption isotherm. Effects of temperature (20–50 °C) and acid concentration (0.5–7.0 M) on the inhibition action were investigated. Polarization curves show that tween‐80 is a mixed‐type inhibitor in sulfuric acid, but prominently inhibits the cathodic reaction. The results obtained from weight loss and potentiodynamic polarization are consistent, and the inhibition action could also be evidenced by AFM images.
Quantum chemical studies of some amino acids on the corrosion of cobalt in sulfuric acid solution
Authors: Gece G. , Bilgiç S. , Türkşen Ö. 
Published: May 2009

AbstractThe inhibitive effect of some amino acids, glycine (Gly), alanine (Ala), valine (Val), leucine (Leu), isoleucine (Ile), serine (Ser), threonine (Thr), methionine (Met), phenylalanine (Phe), tyrosine (Tyr), trytophan (Try), aspartic acid (Asp), asparagine (Asn), glutamic acid (Glu), and lysine (Lys) against the corrosion of cobalt surface is studied by means of semiempirical and density functional methods. The calculated quantum chemical parameters correlated to the inhibition efficiency are, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), the energy gap (ΔE), and Mulliken charges. It is found that the calculated results satisfactorily support the experimental findings.
Modal‐type orthomodular logic
Authors: Domenech Graciela , Freytes Hector , de Ronde Christian 
Published: May 2009

AbstractIn this paper we enrich the orthomodular structure by adding a modal operator, following a physical motivation. A logical system is developed, obtaining algebraic completeness and completeness with respect to a Kripkestyle semantic founded on Baer*‐semigroups as in [22] (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Weak‐quasi‐Stone algebras
Authors: Celani Sergio A. , Cabrer Leonardo M. 
Published: May 2009

AbstractIn this paper we shall introduce the variety WQS of weak‐quasi‐Stone algebras as a generalization of the variety QS of quasi‐Stone algebras introduced in [9]. We shall apply the Priestley duality developed in [4] for the variety N of ¬‐lattices to give a duality for WQS. We prove that a weak‐quasi‐Stone algebra is characterized by a property of the set of its regular elements, as well by mean of some principal lattice congruences. We will also determine the simple and subdirectly irreducible algebras (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Elementary explicit types and polynomial time operations
Authors: Spescha Daria , Strahm Thomas 
Published: May 2009

AbstractThis paper studies systems of explicit mathematics as introduced by Feferman [9, 11]. In particular, we propose weak explicit type systems with a restricted form of elementary comprehension whose provably terminating operations coincide with the functions on binary words that are computable in polynomial time. The systems considered are natural extensions of the first‐order applicative theories introduced in Strahm [19, 20] (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Splitting stationary sets from weak forms of Choice
Authors: Larson Paul , Shelah Saharon 
Published: May 2009

AbstractWorking in the context of restricted forms of the Axiom of Choice, we consider the problem of splitting the ordinals below λ of cofinality θ into λ many stationary sets, where θ < λ are regular cardinals. This is a continuation of [4] (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distributed control of performance management traffic with accuracy objectives
Authors: Jagadish Chundury , Gonsalves Timothy A. 
Published: May 2009

AbstractOne of the important functions of a network management system (NMS) is performance management (PM). PM deals with collecting statistical information to track the effectiveness and utilization of the network and network elements (NE). While this may be done offline, it is often necessary to monitor the network statistics online in real time. The aim of real‐time monitoring is to achieve high accuracy of the statistics while minimizing the use of scarce network bandwidth. The accuracy objective can vary depending on the priority and dynamic severity state of the NE. We define cost, which needs to be optimized, as a function of network traffic and achieved accuracy. Based on the cost, a comparison of push and pull data collection alternatives is done. We have developed a push‐based distributed data collection system that tunes the accuracy objectives, based on the network traffic and the dynamic severity state of the NE. Copyright © 2009 John Wiley & Sons, Ltd.
Characterization of bulk agro‐green composites: Sisal fiber reinforced wheat flour thermoplastics
Authors: Sreekumar P.A.  , Leblanc Nathalie , Saiter Jean M. 
Published: May 2009

AbstractStarch based thermoplastic composites reinforced by short sisal fibers having length less than 1 mm were fabricated by extrusion followed by compression molding. The sisal fiber content varied from 0 to 10% w/w keeping the amount of glycerol (plasticizer) as constant (23% w/w). Investigation proved that an increase in the amount of sisal fibers will decrease the ductile nature of composites. The Young's modulus and hardness value increases as a function of fiber content. The impact strength varied as a function of fiber content. Contact angle analysis showed that incorporation of sisal fibers to the matrix increases its hydrophilic nature. The polar factor and total surface energy increases as a function of fiber content whereas dispersive factor decreases. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Melt‐blowing thermoplastic polyurethane and polyether‐block‐amide elastomers: Effect of processing conditions and crystallization on web properties
Authors: Begenir Asli , Michielsen Stephen , Pourdeyhimi Behnam 
Published: May 2009

AbstractMelt‐blown webs from ester and ether thermoplastic polyurethanes and polyether‐block‐amide (PEBA) elastomers were produced at different die‐to‐collector distances (DCD) to study the correlation between the polymer type and hardness, melt‐blowing process conditions, and web properties. An experimental set up was built to measure the air temperature and velocity profiles below and across the melt‐blowing die to correlate the fiber formation process and polymer crystallization behavior to process conditions and web properties. It was shown that air temperature and velocity profiles follow similar trends with increasing distance below the melt‐blowing die: both drop rapidly until reaching a plateau region approximately 5–6 cm below the die. Thereafter, they remain relatively constant with further increasing distance. It was found that crystallization onset and peak temperatures of all block copolymers in this study fall within this region of rapid velocity and temperature drop. This suggests that the polymers have already started to crystallize and solidify before reaching the collector, the extent of which depends on the crystallization kinetics of the polymer. The strong influence of the crystallization kinetics on web strength was clearly demonstrated in the PEBA series. In particular, the hardest grade produced the lowest web strength mainly because of its high crystallization rate and crystallization onset temperature. It is concluded that the melt‐blown web strength is strongly dependent on the degree of fiber‐to‐fiber adhesion within the web, which is determined by the amount of fiber solidification that occurs prior to the collector. The crystallization kinetics of the polymer and the distances traveled between the die and collector or the exposure time of the polymer melt to process and ambient air were shown to be critical in the amount of fiber solidification attained. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Study on the creep behavior of polypropylene
Authors: Liu Xiaolin , Huang Yajiang , Deng Cong , Wang Xiaojun , Tong Wei , Liu Yuxin , Huang Jianqian , Yang Qi , Liao Xia , Li Guangxian 
Published: May 2009

AbstractThe creep behavior and creep failure law of polypropylene (PP) were investigated by using a multifunctional stress‐aging testing machine under different aging environmental conditions (temperature, UV, and stress). Photoinduced changes in samples were studied using gel permeation chromatography and X‐ray photoelectron spectrometer. Surface morphologies were also observed by scanning electron microscopy. It was found that there is a critical failure strain (εcrit) for PP during the creep course. Once the creep deformation exceeds the εcrit, creep failure of PP takes place very rapidly. The value of εcrit is independent of the tensile stress and UV irradiation, whereas it is only affected by the temperature and the nature of the PP, such as molecular weight and molecular structure. With increasing temperature, the value of εcrit increases gradually. In addition, the creep rate of PP increases rapidly with increasing tensile stress and temperature as well as under irradiation with UV light. This study may provide a new way to predict the service lifetime of PP. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
In‐situ synthesis of poly(ethylene terephthalate)/clay nanocomposites using TiO2/SiO2 sol‐intercalated montmorillonite as polycondensation catalyst
Authors: Yin Ming , Li Chuncheng , Guan Guohu , Yuan Xuepei , Zhang Dong , Xiao Yaonan 
Published: May 2009

AbstractA novel organic montmorillonite, which could act as both polycondensation catalyst of poly(ethylene terephthalate) (PET) and filler of PET/clay nanocomposites, was prepared. Original montmorillonite was first treated with different amounts of poly(vinylpyrrolidone) (PVP), and then intercalated by TiO2/SiO2 sol to gain polycondensation catalytic activity. The acquired clay possessed excellent thermal stability and would not degrade during the polycondensation step. PET/clay nanocomposites were prepared via in‐situ polymerization using the organo‐clay as polycondensation catalysts. The morphologies of the nanocomposites were characterized by X‐ray diffraction and transmission electron microscope. The results indicated that the amount of PVP and TiO2/SiO2 sol strongly affected the dispersion state of the clay, and finally, partially exfoliated PET/clay nanocomposites were obtained. The nanocomposites had better properties than pure PET due to the incorporation of the delaminated clay layers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Monomer/polymer Schiff base copper(II) complexes for catalytic oxidative polymerization of 2,2′‐dihydroxybiphenyl
Authors: Bi̇li̇ci̇ Ali̇ , Kaya İsmet , Doğan Fati̇h 
Published: May 2009

AbstractCatalytic oxidative polymerization of 2,2′‐dihydroxybiphenyl (DHBP) was performed by using both the Schiff base monomer‐Cu(II) complex and Schiff base polymer‐Cu(II) complex compounds as catalysts and hydrogen peroxide as oxidant, respectively. The dependence of monomer conversion and molecular weight distribution on various reaction parameters, including time, temperature, solvent as well as the amount of catalyst and oxidant were investigated. The structure of the poly‐2,2′‐dihydroxybiphenyl (PDHBP) was confirmed by UV‐vis, IR, 1H and 13C NMR spectroscopy techniques. The electrochemical and thermal properties of PDHBP were also studied. DSC data revealed that PDHBP was amorphous. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2977–2984, 2009
Electrochemical synthesis of PEDOT derivatives bearing imidazolium‐ionic liquid moieties
Authors: Döbbelin Markus , Pozo‐Gonzalo Cristina , Marcilla Rebeca , Blanco Raúl , Segura José L. , Pomposo Jose A. , Mecerreyes David 
Published: May 2009

AbstractNovel poly(3,4‐ethylenedioxythiophene) (PEDOT) polymers bearing imidazolium‐ionic liquid moieties were synthesized by electrochemical polymerizations. For this purpose, new functional monomers were synthesized having an 3,4‐ethylenedioxythiophene (EDOT) unit and an imidazolium‐ionic liquid with different anions such as tetrafluoroborate (BF), bis(trifluoromethane)sulfonimide ((CF3SO2)2N−), and hexafluorophosphate (PF). Next, polymer films were obtained by electrochemical synthesis in dicholoromethane solutions. Obtained polymers were characterized, revealing the characteristics of PEDOT in terms of electrochemical and spectroelectrochemical properties, FTIR, 1H NMR, and AFM microscopy. Interestingly, the hydrophobic character of electropolymerized films could be modified depending on the anion type. The hydrophobicity followed the trend PF > (CF3SO2)2N− > BF > pure PEDOT as determined by water contact angle measurements. Furthermore, the polymers could be dissolved in a range of polar organic solvents such as dimethylformamide, propylene carbonate, and dimethyl sulfoxide making these polymers interesting candidates for wet processing methods. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3010–3021, 2009
Synthesis and characterization of amphiphilic poly(N‐vinyl pyrrolidone)‐b‐poly(ε‐caprolactone) copolymers by a combination of cobalt‐mediated radical polymerization and ring‐opening polymerization
Authors: Jeon Hyun Jeong , You Young Chang , Youk Ji Ho 
Published: May 2009

AbstractAn amphiphilic block copolymer of poly(N‐vinyl pyrrolidone)‐b‐poly(ε‐caprolactone) (PVP‐b‐PCL) was synthesized by a combination of cobalt‐mediated radical polymerization (CMRP) and ring‐opening polymerization (ROP). The micellar characteristics of this copolymer were subsequently investigated. PVP (Mn = 11,400, Mw/Mn = 1.32) was synthesized at 20 °C via CMRP using a molar ratio of [VP]0/[V‐70]0/[Co]0 = 150/8/1. The PVP was then reacted with 2,2′‐azobis[2‐methyl‐N‐(2‐hydroxyethyl)propionamide] (VA‐086) to modify its cobalt complex chain end to a hydroxyl group. The cobalt (Co) content in the resulting PVP‐OH was 1.2 ppm, indicating that all of the covalent CoC bonds were cleaved and reacted with VA‐086, and that the separated cobalt complexes were successfully removed. The ROP of CL was subsequently carried out using the produced PVP‐OH as a macroinitiator at 110 °C. The GPC trace of PVP‐b‐PCL was monomodal without any tailing caused by the residual PVP‐OH, indicating that the initiation efficiency was very high. The critical micelle concentration (CMC) of PVP‐b‐PCL (Mn = 18,000, Mw/Mn = 1.35) was 0.015 mg/mL. The PVP‐b‐PCL micelles were spherical in shape with an average diameter of 105 nm. The nanosized PVP‐b‐PCL micelles show promise as novel drug carriers in biomedical and pharmaceutical applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3078–3085, 2009