bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Mixed Phthalocyaninato and meso‐Tetrakis(4‐chlorophenyl)porphyrinato Triple‐Decker Complexes − Revealing the Origin of Their Electronic Absorptions
Authors: Sun Xuan , Li Renjie , Wang Daqi , Dou Jianmin , Zhu Peihua , Lu Fanli , Ma Changqin , Choi Chi‐Fung , Cheng Diana Y. Y. , Ng Dennis K. P. , Kobayashi Nagao , Jiang Jianzhuang 
Published: July 2004

AbstractTwo series of mixed phthalocyaninato and porphyrinato rare earth(III) triple‐decker complexes [M2(Pc)(TClPP)2] (1a−10a) and [M2(Pc)2(TClPP)] (1b−11b) [M = Y, La−Er except Ce and Pm; Pc = phthalocyaninate; TClPP = tetrakis(4‐chlorophenyl)porphyrinate] have been prepared by treating the half‐sandwich complexes [M(TClPP)(acac)] (acac = acetylacetonate), generated in situ from [M(acac)3]·nH2O and H2(TClPP), with Li2(Pc). All the triple‐decker complexes have been characterized by a wide range of spectroscopic and electrochemical methods. The molecular structures of [M2(Pc)(TClPP)2] (M = Y, Ho) have also been determined, and show a symmetrical disposition of ligands, with two outer domed TClPP and one inner Pc rings. A systematic investigation of the optical and electrochemical data of these complexes has revealed the nature of the HOMO and LUMO, as well as the origin of the electronic absorptions of these triple‐decker complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Amperometric Detection of Catechol and Catecholamines by Immobilized Laccase from DeniLite
Authors: Quan De , Shin Woonsup 
Published: August 2004

AbstractDeniLite laccase immobilized Pt electrode was used for detection of catechol and catecholamines. The enzymatically oxidized substrates were measured amperometrically. The sensitivities are 210, 75, 60 and 45 nA/μM with the upper limits of linear ranges of 58, 40, 55 and 55 μM and the detection limits (S/N=3) of 0.07, 0.2, 0.3 and 0.4 μM for catechol, dopamine (DA), norepinephrine (NEPI) and epinephrine (EPI), respectively. The response time (t90%) is about 2 seconds for each substrate and the long‐term stability is around 40–50 days with retaining 80% of initial activity. The very fast response and the remarkable long‐term stability are the principal advantages of this sensor. In case of catechol, the pH response of the sensor is mainly determined by enzyme's pH profile, however, in case of catecholamines, both enzyme's pH profile and reversibility of the substrate are operated and the optimal pHs for NEPI and EPI shift towards acidic range compared to that for DA. The presence of ascorbic acid (<50 μM) did not interfere with the measurement.
Realization of Rhodium Metal‐Oxide Electrode in Indifferent Electrolytes
Authors: Juodkazytė J. , Juodkazis K. 
Published: August 2004

AbstractThe pH‐dependence of the stationary open‐circuit potentialEi=0stof rhodium electrode with a surface layer of anodically formed insoluble compounds has been studied in sulfate and phosphate solutions by means of cyclic voltammetry and chronopotentiometry. The range of potentials of the investigations performed has been confined to the region of rhodium electrochemical oxidation/reduction, i.e., 0.2<E<1.2 V (RHE) in order to prevent any possible interference of other reactions such as H2and O2evolution. It has been shown that rhodium electrode with a layer of surface compounds formed anodically atE<<1.23 V (RHE) behaves like a reversible metal‐oxide electrode within the range of pH values from ca. 1.0 to ca. 8.0. It has been presumed that the stationary potential of such electrode is determined by the equilibrium of the following electrochemical reaction: Rh+3H2O⇔︁Rh(OH)3+3H++3e−. The pH‐dependence of the reversible potential ofEelectrode has been found to be:E=Ei=0st=0.69−0.059 pH, V. In acid solutions (pH<2.0) rhodium hydroxide dissolves into the electrolyte, therefore, to reach equilibrium, the solution must be saturated with Rh(OH)3. This has been achieved by adding Rh3+ions in the form of Rh2(SO4)3. The solubility product of Rh(OH)3, estimated from the experimentalE−pH dependence obtained, is ca. 1.0×10−48, which is close to the value given in literature.
Pleistocene migration routes into the Americas: Human biological adaptations and environmental constraints
Authors: Hall Roberta , Roy Diana , Boling David 
Published: July 2004

AbstractTheories about the routes and timing of human entry into the Americas during the Late Pleistocene usually involve models of lowered sea levels and ice‐free land in Beringia, supported by locations and dates of archeological sites in Northeastern Asia and Northwestern America. Recently, paleoecological reconstructions made possible by advances in geochronology and climatology have received attention. Now morphological adaptations and environmental constraints that affect human activities and physiology need to be considered. Physical accessibility to an area, important as it is, does not alone determine a migration route. In considering any route, anthropologists need to ask: What would it have been like to live in this environment? Did it provide an amenable climate that supported human health and comfort? Between 16,000 and 11,000 cal BP, did this route provide enough food resources and enough hours of sunlight for people with an Upper Paleolithic technology to make a living? We discuss these questions and show ways in which the coastal‐entry model is superior to the interior route through Beringia and an ice‐free corridor.
Has the combination of genetic and fossil evidence solved the riddle of modern human origins?
Authors: Pearson Osbjorn M. 
Published: July 2004

AbstractDebate over the origin of modern humans continues without a clear end in sight. Currently, the genetic and fossil evidence is still used to support two different interpretations of the origin of modern humans. Some researchers claim that the genetic evidence is compatible with either an Out‐of‐Africa or a Multiregional model, while other scientists argue that the evidence supports only a Multiregional model of evolution. I argue that the fossil record and archeological evidence constrain interpretation of the genetic evidence and imply that very little, if any, admixture with Eurasian archaic hominins such as the Neanderthals occurred during the spread of modern humans out of Africa.
PBI‐Based Polymer Membranes for High Temperature Fuel Cells – Preparation, Characterization and Fuel Cell Demonstration
Authors: Li Q. , He R. , Jensen J.O. , Bjerrum N.J. 
Published: July 2004

AbstractProton exchange membrane fuel cell (PEMFC) technology based on perfluorosulfonic acid (PFSA) polymer membranes is briefly reviewed. The newest development in alternative polymer electrolytes for operation above 100 °C is summarized and discussed. As one of the successful approaches to high operational temperatures, the development and evaluation of acid doped polybenzimidazole (PBI) membranes are reviewed, covering polymer synthesis, membrane casting, acid doping, physicochemical characterization and fuel cell testing. A high temperature PEMFC system, operational at up to 200 °C based on phosphoric acid‐doped PBI membranes, is demonstrated. It requires little or no gas humidification and has a CO tolerance of up to several percent. The direct use of reformed hydrogen from a simple methanol reformer, without the need for any further CO removal, has been demonstrated. A lifetime of continuous operation, for over 5000 h at 150 °C, and shutdown‐restart thermal cycle testing for 47 cycles has been achieved. Other issues such as cooling, heat recovery, possible integration with fuel processing units, associated problems and further development are discussed.
CO Tolerance of Commercial Pt and PtRu Gas Diffusion Electrodes in Polymer Electrolyte Fuel Cells
Authors: Hajbolouri F. , Andreaus B. , Scherer G.G. , Wokaun A. 
Published: July 2004

AbstractThe CO tolerance of commercial Pt and PtRu anode electrodes from different suppliers (E‐Tek and Tanaka) has been examined in polymer electrolyte fuel cells (PEFC) using AC‐impedance spectroscopy along steady‐state current‐voltage curves. A simple mathematical model has been derived in order to extract important kinetic parameters for CO poisoning on different anode electrodes. The Tanaka PtRu (40:60) electrode demonstrated the best CO tolerance under the selected operating conditions.Inductive behavior in the low frequency region of the impedance spectra for the E‐Tek Pt and PtRu electrode proved to be characteristic for CO poisoning. However, the impedance spectra of the Tanaka PtRu electrode did not show any inductive behavior and its CO surface coverage, extracted by fitting the experimental data to the model, was lower than the surface CO coverage of the E‐Tek electrodes.
Hydrogen Production via Autothermal Reforming of Diesel Fuel
Authors: Pasel J. , Meißner J. , Porš Z. , Palm C. , Cremer P. , Peters R. , Stolten D. 
Published: July 2004

AbstractHydrogen, for the operation of a polymer electrolyte fuel cell, can be produced by means of autothermal reforming of liquid hydrocarbons. Experiments, especially with ATR 4, which produces a molar hydrogen stream equivalent to an electrical power in the fuel cell of 3 kW, showed that the process should be preferably run in the temperature range between 700 ° and 850 °. This ensures complete hydrocarbon conversion and avoids the formation of considerable amounts of methane and organic compounds in the product water. Experiments with commercial diesel showed promising results but insufficient long‐term stability. Experiments concerning the ignition of the catalytic reaction inside the reformer proved that within 60 s after the addition of water and hydrocarbons the reformer reached 95% of its maximum molar hydrogen flow. Measurements, with respect to reformer start‐up, showed that it takes approximately 7 min. to heat up the monolith to a temperature of 340 ° using an external heating device. Modelling is performed, aimed at the modification of the mixing chamber of ATR Type 5, which will help to amend the homogeneous blending of diesel fuel with air and water in the mixing chamber.
The contribution of a satellite market to price discovery: Evidence from the Singapore exchange
Authors: Covrig Vicentiu , Ding David K. , Low Buen Sin 
Published: July 2004

AbstractThe Singapore Exchange (SGX), a small satellite market, successfully competes with a large home market, the Osaka Securities Exchange (OSE), in trading the Nikkei 225 futures index. In this paper, we investigate the contribution of the SGX to price discovery and shed light on the reasons for its continued success. Evidence is provided from information revelation and price discovery of three competing but informationally linked markets of the Nikkei 225 index—domestic spot (Tokyo Stock Exchange), domestic futures (OSE), and foreign futures (SGX), which represents the satellite market. Overall, the futures market contributes 77% to price discovery, with the satellite market contributing 42% of the futures and 33% of the total price discovery. These figures, surprisingly, far exceed the satellite market's share of trading volume. Support is provided for the extended trading hours on the SGX for three of the four non‐overlapping trading sub‐periods. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:981–1004, 2004
Liquidity constraints and the hedging role of futures spreads
Authors: Wong Kit Pong 
Published: July 2004

AbstractThis paper examines the behavior of the competitive firm under price uncertainty in general and the hedging role of futures spreads in particular. The firm has access to a commodity futures market where unbiased nearby and distant futures contracts are transacted. A liquidity constraint is imposed on the firm such that the firm is forced to prematurely close its distant futures position whenever the net interim loss due to its nearby and distant futures positions exceeds a threshold level. This paper shows that the liquidity constrained firm optimally opts for a long nearby futures position and a short distant futures position should the firm be prudent, thereby rendering the optimality of using futures spreads for hedging purposes. This paper further shows that the firm's production decision is adversely affected by the presence of the liquidity constraint. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:909–921, 2004
Unequivocal evidence of genotoxic potential of argemone oil in mice
Authors: Ansari Kausar M. , Chauhan Lalit K.S. , Dhawan Alok , Khanna Subhash K. , Das Mukul 
Published: August 2004

AbstractConsumption of mustard oil adulterated with argemone oil leads to a clinical condition, commonly referred to as “Epidemic Dropsy.” Since in vitro studies have shown that sanguinarine, an active benzophenanthridine alkaloid of argemone oil, intercalates DNA molecule, the in vivo clastogenic and DNA damaging potential of argemone oil was investigated in mice. Swiss albino mice were intraperitoneally administered 0.5, 1.0, 2.0 and 4.0 ml/kg body wt. of argemone oil to analyze chromosome aberrations and micronucleus test, while 0.25, 0.5, 1.0 and 2.0 ml/kg body wt. were given for alkaline comet assay. The frequencies of chromosomal aberrations and micronucleated erythrocytes formation in mouse bone marrow cells increased in a dose‐dependent manner following argemone oil treatment. However, significant induction in chromosomal aberrations (83%) and micronucleated erythrocytes formation (261%) were observed at a minimum dose of 1.0 ml/kg. The results of comet assay revealed DNA damage in blood, bone marrow and liver cells following argemone oil treatment. Olive tail moment (OTM) and tail DNA showed significant increase in bone marrow (35–44%) and blood cells (25–40%) even at a dose of 0.25 ml/kg body wt. of argemone oil. In liver cells, OTM was significantly increased (20%) at a dose of 0.25 ml/kg, while all the comet parameters including OTM, tail length and tail DNA showed significant increase (31–101%) at a dose of 0.5 ml/kg. These results clearly suggest that single exposure of argemone oil even at low doses produces genotoxic effects in mice. © 2004 Wiley‐Liss, Inc.
Sonographic assessment of the liver in children with psoriasis
Authors: Pietrzak Aldona , Dybiec Ewa , Urban Janusz , Chodorowska Grażyna 
Published: July 2004

AbstractPurposeThe aim of this study was to compare the size and echotexture of the liver in psoriatic and healthy children.MethodsIn 70 psoriatic and 43 healthy children, longitudinal sonograms of the liver were obtained along standardized section planes defined by the anterior axillary line, medioclavicular line, and midline. The livers' size and echotexture were examined and compared between the study groups.ResultsThe measurements of the liver along the 3 section planes were not significantly different between psoriatic and healthy children. Parenchymal liver echogenicity in psoriatic children was neither decreased nor increased.ConclusionsNo abnormality in size or echotexture of the liver was found in the psoriatic children. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:344–347, 2004
Comparative cis‐regulatory analyses identify new elements of the mouse Hoxc8 early enhancer
Authors: Wang Wayne C.H. , Anand Sanjay , Powell Dennis R. , Pawashe Aruna B. , Amemiya Chris T. , Shashikant Cooduvalli S. 
Published: July 2004

AbstractThe Hoxc8 early enhancer is a 200 bp region that controls the early phase of Hoxc8 expression during mouse embryonic development. This enhancer defines the domain of Hoxc8 expression in the neural tube and mesoderm of the posterior regions of the developing embryo. Five distinct cis‐acting elements, A–E, were previously shown to govern early phase Hoxc8 expression. Significant divergence between mammalian and fish Hoxc8 early enhancer sequences and activities suggested additional cis‐acting elements. Here we describe four additional cis‐acting elements (F‐I) within the 200 bp Hoxc8 early enhancer region identified by comparative regulatory analysis and transgene‐mutation studies. These elements affect posterior neural tube and mesoderm expression of the reporter gene, either singly or in combination. Surprisingly, these new elements are missing from the zebrafish and Fugu Hoxc8 early enhancer sequences. Considering that fish enhancers direct robust reporter expression in transgenic mouse embryos, it is tempting to postulate that fish and mammalian Hoxc8 early enhancers utilize different sets of elements to direct Hoxc8 early expression. These observations reveal a remarkable plasticity in the Hoxc8 early enhancer, suggesting different modes of initiation and establishment of Hoxc8 expression in different species. We postulate that extensive restructuring and remodeling of Hox cis‐regulatory regions occurring in different taxa lead to relatively different Hox expression patterns, which in turn may act as a driving force in generating diverse axial morphologies. J. Exp. Zool. (Mol. Dev. Evol.) 302B:000–000, 2004. © 2004 Wiley‐Liss, Inc.
Transient complexes of redox proteins: structural and dynamic details from NMR studies
Authors: Prudêncio Miguel , Ubbink Marcellus 
Published: August 2004

AbstractRedox proteins participate in many metabolic routes, in particular those related to energy conversion. Protein–protein complexes of redox proteins are characterized by a weak affinity and a short lifetime. Two‐dimensional NMR spectroscopy has been applied to many redox protein complexes, providing a wealth of information about the process of complex formation, the nature of the interface and the dynamic properties of the complex. These studies have shown that some complexes are non‐specific and exist as a dynamic ensemble of orientations while in other complexes the proteins assume a single orientation. The binding interface in these complexes consists of a small hydrophobic patch for specificity, surrounded by polar, uncharged residues that may enhance dissociation, and, in most complexes, a ring or patch of charged residues that enhances the association by electrostatic interactions. The entry and exit port of the electrons is located within the hydrophobic interaction site, ensuring rapid electron transfer from one redox centre to the next. Copyright © 2004 John Wiley & Sons, Ltd.
Sensorial and physicochemical quality responses of pears (cv Rocha) to long‐term storage under controlled atmospheres
Authors: Galvis‐Sánchez Andrea C , Fonseca Susana C , Morais Alcina MMB , Malcata F Xavier 
Published: August 2004

AbstractPears (cv Rocha) kept under controlled atmospheres (CA) and air were evaluated after long‐term storage in terms of sensory attributes and physicochemical parameters, namely colour, firmness, polyphenoloxidase (PPO) activity and concentration of hydroxycinnamic compounds. The CA conditions were all combinations of 2 and 4% (v/v) O2 with 0.5 and 1.5% (v/v) CO2. Storage under CA conditions produced a beneficial effect on ‘Rocha’ pears in maintaining their quality and, consequently, in extending their shelf life and acceptability. Clear differences in sensorial attributes, colour parameters and PPO activity were found between CA‐ and air‐stored pears. The effect provided by the CA conditions persisted throughout the time of exposure to the open air. The 2% O2 concentration produced a more beneficial effect than its 4% counterpart on the sensorial and physical characteristics of the pears. The former concentration of O2 prevented yellowing and allowed regular softening, hence keeping a high flavour quality. No clear effects could be associated with CO2 levels. Empirical models were developed that describe the effects of O2 and CO2 concentrations, as well as time at room temperature on physicochemical parameters pertaining to ‘Rocha’ pears. Copyright © 2004 Society of Chemical Industry
The effect of daily temperature on truss flowering rate of tomato
Authors: Pék Zoltán , Helyes Lajos 
Published: August 2004

AbstractThe rate of appearance of tomato inflorescence is important parameter of yield prediction models. Number of macroscopically observable inflorescences related to unit time was used to characterize the rate of development in case of indeterminate tomato. Truss flowering rate showed similar pattern to truss appearance rate, and it was closely connected with temperature. The present experiments attempted to calculate functions that can estimate truss flowering rate up to the 10th truss. These functions are the basis of characterizing the whole flowering process in relation to temperature during the generative period of indeterminate tomato. Copyright © 2004 Society of Chemical Industry
Sensory and chemical characteristics of Canadian ice wines
Authors: Nurgel Canan , Pickering Gary J , Inglis Debra L 
Published: August 2004

AbstractFifty‐one Canadian ice wines, representative of a range of varieties and vintages, were evaluated chemically and 20 wines further evaluated sensorally. Ice wines from British Columbia and Ontario were significantly different for a range of chemical and sensory attributes. British Columbia ice wines had higher titratable acidity, acetic acid and glucose, and lower colour and ethyl acetate content compared with those from Ontario. Apricot, raisin, honey and oak aromas were more pronounced in Ontario ice wines, while British Columbia ice wines had higher intensities of pineapple and oxidized aromas. Riesling ice wines had higher titratable acidity and glucose and lower pH andA420values compared with Vidal. Vintage effects were also found for pH,A420, glucose, fructose, ethanol and ethyl acetate. Copyright © 2004 Society of Chemical Industry
In‐gel detection and study of the role of flavonol 3‐glucosidase in the bitter taste generation in tartary buckwheat
Authors: Suzuki Tatsuro , Honda Yutaka , Funatsuki Wakako , Nakatsuka Keiji 
Published: August 2004

AbstractThe present study demonstrated that flavonol 3‐glucosidase (f3g) is an important cause of bitter taste generation in tartary buckwheat (Fagopyrum tataricum) flour using the f3g complement test. To screen the f3g deletion line, which must have little bitter taste, an in‐gel method to detect individual f3g isozymes in tartary buckwheat seeds was developed. The f3g isozymes in tartary buckwheat seed were stained using a rutin–copper complex on the native–PAGE gel. This method was able to clearly detect as little as 1.4 ng of individual f3g isozymes within 20 min following electrophoresis. With this method, screening of the f3g deletion line can be conducted efficiently and will result in a better taste in tartary buckwheat flour. Copyright © 2004 Society of Chemical Industry
Assessment of two‐ and three‐parameter Lewicki models for description of sorption phenomena of starch materials
Authors: McMinn Wendy AM , Al‐Muhtaseb Ala'a , Magee T Ronald A 
Published: August 2004

AbstractExperimental moisture sorption isotherm data for raw potato, starch gels (potato, starch–sugar and starch–salt) and starch powders (potato, highly amylopectin and highly amylose) were determined using a gravimetric static method at 30, 45 and 60 °C and over a relative humidity range 0.10–0.84. The raw potato, starch powders and starch gels exhibited type II behaviour, with type III form being observed on incorporation of sugar, or salt, into the starch gel matrix. The two‐parameter Lewicki relationship, and the three‐parameter Lewicki and GAB equations were considered for description of the experimental data. A nonlinear least square regression technique was used to evaluate the constants for the models. The three‐parameter Lewicki model was found to be the most suitable for describing the sorption characteristics of raw potato, potato starch, starch–sugar and starch–salt gels within the investigated temperature and water activity range. However, both Lewicki models gave an inadequate representation of the data for potato, high amylopectin and high amylose starch powders. Copyright © 2004 Society of Chemical Industry