bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensory and quality analysis of different melon cultivars after prolonged storage
Authors: Hoberg Edelgard , Ulrich Detlef , Schulz Hartwig , Tuvia‐Alkali Sharon , Fallik Elazar 
Published: September 2003

AbstractThe purpose of this work was to evaluate the sensory and general quality of four different melon cultivars (Cucumis melo L.) immediately after harvest and at the end of storage and marketing simulation. After 16 days of storage at 5°C and additional 3 days at 20°C, only cultivar ‘C‐8’ had a poor general appearance due to significant low firmness and relatively high decay incidence compared to the cultivars ‘5080’, ‘Ideal’ and ‘7302’. The cultivar ‘7302’ was found to have the higher overall quality. The human‐sensory and organoleptic analyses revealed that the cultivars can be differentiated on the basis of retronasal odour. The texture of the melons seems to be dependent on the genotype. All the complex perceptions analysed in this work contribute to the acceptability, which is in the fresh fruits of ‘7302’ the best and in ‘Ideal’ the worst. After storage and marketing simulation ‘Ideal’ and ‘C‐8’ are no longer favoured, but ‘5080’ and ‘7302’, despite different characters, were found to be similarly accepted. It can be concluded that with the aid of the human‐sensory method developed to characterize the melon varieties it is possible to distinguish the different genotypes.
Expression and characterization of chicken ovoinhibitor in Pichia pastoris
Authors: Begum Shamima , Saito Akira , Kato Akio , He Jianwei , Azakami Hiroyuki 
Published: September 2003

AbstractChicken ovoinhibitor cDNA was prepared by reverse transcriptase‐polymerase chain reaction (RT‐PCR) using chicken oviduct mRNA. The ovoinhibitor cDNA was successfully cloned downstream from the AOXI promoter of pPICZ α A plasmid vector to facilitate its expression in the methylotrophic yeastPichia pastoris. The pPICZαA carrying the ovoinhibitor cDNA was integrated into the Pichia genome. The secreted recombinant ovoinhibitor was purified by ion‐exchange chromatography on a DEAE sepharose column. The recombinant ovoinhibitor had a molecular mass of 49 kDa, as determined from sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and time of flight‐mass spectrometry (TOF‐MS) analyses. The recombinant ovoinhibitor, just as the native ovoinhibitor, showed inhibitory activity against trypsin, chymotrypsin and elastase.
Synthesis of Monosaccharide‐Derived Spirocyclic Cyclopropylamines and Their Evaluation as Glycosidase Inhibitors
Authors: Blüchel Christian , Ramana Chepuri Venkata , Vasella Andrea 
Published: September 2003

AbstractThe glucose‐, mannose‐, and galactose‐derived spirocyclic cyclopropylammonium chlorides 1a–1d, 2a–2d and 3a–3d were prepared as potential glycosidase inhibitors. Cyclopropanation of the diazirine 5 with ethyl acrylate led in 71% yield to a 4 : 5 : 1 : 20 mixture of the ethyl cyclopropanecarboxylates 7a–7d, while the Cu‐catalysed cycloaddition of ethyl diazoacetate to the exo‐glycal 6 afforded 7a–7d (6 : 2 : 5 : 3) in 93–98% yield (Scheme 1). Saponification, Curtius degradation, and subsequent addition of BnOH or t‐BuOH led in 60–80% overall yield to the Z‐ or Boc‐carbamates 11a–11d and 12a–12d, respectively. Hydrogenolysis of 11a–11d afforded 1a–1d, while 12a–12d was debenzylated to 13a–13d prior to acidic cleavage of the N‐Boc group. The manno‐ and galacto‐isomers 2a–2d and 3a–3d, respectively, were similarly obtained in comparable yields (Schemes 2 and 4). Also prepared were the differentially protected manno‐configured esters 24a–24d; they are intermediates for the synthesis of analogous N‐acetylglucosamine‐derived cyclopropanes (Scheme 3).The cyclopropylammonium chlorides 1a–1d, 2a–2d and 3a–3d are very weak inhibitors of several glycosidases (Tables 1 and 2). Traces of Pd compounds, however, generated upon catalytic debenzylation, proved to be strong inhibitors. PdCl$\rm{_{4}^{2-}}$ is, indeed, a reversible, micromolar inhibitor for the β‐glucosidases from C. saccharolyticum and sweet almonds (non‐competitive), the β‐galactosidases from bovine liver and from E. coli (both non‐competitive), the α‐galactosidase from Aspergillus niger (competitive), and an irreversible inhibitor of the α‐glucosidase from yeast and the α‐galactosidase from coffee beans. The cyclopropylamines derived from 1a–1d or 3a–3d significantly enhance the inhibition of the β‐glucosidase from C. saccharolyticum by PdCl$\rm{_{4}^{2-}}$, lowering the Ki value from 40 μM (PdCl$\rm{_{4}^{2-}}$) to 0.5 μM for a 1 : 1 mixture of PdCl$\rm{_{4}^{2-}}$ and 1d. A similar effect is shown by cyclopropylamine, but not by several other amines.
Cleavage of Qinghaosu (Artemisinin) Induced by Non‐Iron Transition‐Metal Ions in the Presence of Excess Cysteine
Authors: Wu Yikang , Liu He‐Hua 
Published: September 2003

AbstractIn the presence of an excess of cysteine, a catalytic amount of a non‐iron transition‐metal ion (Co2+, Cu2+, Ni2+, Ti4+, and Mn2+) may also induce cleavage of qinghaosu (artemisinin; 1) to give those end products previously reported for Fe2+‐mediated degradation.
Pyrrolizidine Alkaloids from Onosma leptantha
Authors: Kretsi Ourania , Aligiannis Nektarios , Skaltsounis Alexios Leandros , Chinou Ioanna B. 
Published: September 2003

AbstractThree new pyrrolizidine alkaloids, leptanthine (2), its corresponding N‐oxide 1, and N‐oxide of 3′‐O‐acetylechihumiline (3), were isolated from the aerial parts of Onosma leptantha, together with two known alkaloids of the same type, echihumiline (5) and echihumiline N‐oxide (4). Their structures and configurations were determined by chemical and spectroscopic methods, especially 1D and 2D NMR analyses, including long‐range 1H,15N correlations at natural abundance.
Synthesis of Triazolo[1,5‐a]triazin‐7‐one Derivatives and Highly Functionalized [1,2,4]Triazoles
Authors: Heras Montserrat , Font David , Linden Anthony , Villalgordo José M. 
Published: September 2003

AbstractThe synthesis of novel triazolo[1,5‐a]triazin‐7‐ones is presented. Starting from 3‐amino‐5‐sulfanyl‐1,2,4‐triazole, the synthetic sequence involved alkylation with benzyl bromide, reaction with p‐nitrophenyl chloroformate followed by treatment with a primary amine, and condensation with diethoxymethyl acetate. Final oxidation of the thioether moiety with 3‐chloroperbenzoic acid provided 2‐(benzylsulfonyl)[1,2,4]triazolo[1,5‐a][1,3,5]triazin‐7‐ones 5a and 5b in good overall yields. Treatment of 5a and 5b with secondary amines provided highly functionalized [1,2,4]triazoles through an unexpected triazinone ring opening. A mechanism for this transformation is proposed.
Selenium‐Containing Heterocycles from Isoselenocyanates: Synthesis of 1H‐5‐Selena‐1,3,6‐triazaaceanthrylene Derivatives
Authors: Atanassov Plamen K. , Linden Anthony , Heimgartner Heinz 
Published: September 2003

AbstractThe reaction of aryl isoselenocyanates 8 with methyl 3‐amino‐4‐chloro‐1‐ethylpyrrolo[3,2‐c]quinoline‐2‐carboxylate (6) in boiling pyridine leads to tetracyclic selenaheterocycles of type 9 in high yield (Scheme 3). A reaction mechanism via an intermediate selenoureido derivative A and cyclization via nucleophilic substitution of Cl by Se is proposed (Schemes 3 and 5). The reaction of 6 with 4‐bromophenyl isothiocyanate yields the analogous thiaheterocycle 12 (Scheme 4). The molecular structures of 9c and 12 have been established by X‐ray crystallography.
When executives influence peers: Does function matter?
Authors: Enns Harvey G. , McFarlin Dean B. 
Published: September 2003

AbstractExecutives often spend considerable time and energy trying to influence peers to support new initiatives
(e.g., Conger, 1998; Enns, Huff, & Golden, 2001). That said, we know relatively little about how
executives actually influence their peers. Using a sample of 132 executives, the present study found that
finance executives differed the most from other executives in terms of the influence tactics and contexts used
when influencing peers. Human resource executives also differed considerably from their counterparts in
operations regarding influence tactics and contexts. Possible explanations, directions for future research, and
implications for management are discussed. © 2003 Wiley Periodicals, Inc.
High‐level employee involvement at Delta Air Lines
Authors: Kaufman Bruce E. 
Published: September 2003

AbstractAs described in this unique case study, Delta Air Lines operates one of the most advanced, high‐level
employee involvement programs in the nation. Based on in‐depth field study and personal interviews, the
development, structure, operation, and business goals of the program are described. The study then summarizes
the business benefits and costs of this type of high‐level employee involvement program and concludes
with 12 “lessons learned.” © 2003 Wiley Periodicals, Inc.
Perceptions of parent‐child attachment, social self‐efficacy, and peer relationships in middle childhood
Authors: Coleman Priscilla K. 
Published: September 2003

AbstractRelationships among attachment to each parent, children's social self‐efficacy, and the quality of peer relations (attachment to peers and perceptions of victimization) were explored with 67 fifth and sixth graders (31 female) attending a rural elementary school. Results of hierarchical multiple regression analyses revealed main effects for gender and attachment to mother relative to the attachment to peers variable, with girls and more securely attached children reporting higher quality attachment to peers. Main effects were also detected for gender and attachment to father relative to social self‐efficacy, with girls and more securely attached children exhibiting higher self‐efficacy. No main effects were observed relative to the peer victimization variable. None of the interaction effects involving gender and attachment to each parent relative to attachment to peers, peer victimization, and social self‐efficacy were significant. Finally, evidence for mediation of attachment to father on attachment to peers by children's social self‐efficacy was revealed. Implications of the results are discussed and ideas for future research are provided. Copyright © 2003 John Wiley & Sons, Ltd.
Thermo‐solvatochromism of betaine dyes in aqueous alcohols: explicit consideration of the water–alcohol complex
Authors: Tada Erika B. , Silva Priscilla L. , El Seoud Omar A. 
Published: September 2003

AbstractThermo‐solvatochromism of 2,6‐dichloro‐4‐(2,4,6‐triphenylpyridinium‐1‐yl)‐phenolate, 1‐methylquinolinium‐8‐olate and 4‐[2‐(1‐methylpyridinium‐4‐yl)ethenyl]‐phenolate, in the temperature ranges 10–45°C (methanol) and 10–60°C (1‐ and 2‐propanol) was investigated in binary water–alcohol mixtures. Thermo‐solvatochromic data were treated according to a modified model that explicitly considers the presence of 1:1 water–alcohol species in bulk solution, and its exchange reactions with water and alcohol in the solvation micro‐sphere of the probe employed. Concentrations of these complex species were calculated from density data. Plots of the empirical solvent polarity parameter, ET, versus effective mole fraction of water in the binary mixtures indicate that the probes are preferentially solvated by the alcohol, except for one case. A temperature increase causes gradual desolvation of the probe, due to a decrease in the H‐bonding abilities of all components of the binary solvent mixture. Copyright © 2003 John Wiley & Sons, Ltd.
Kinetics of protonation of anthracene radical anions in DMSO by a series of substituted phenols
Authors: Jaworski Jan S. , Cembor Marek 
Published: September 2003

AbstractThe rate constants kH for proton transfer from a series of substituted phenols to anthracene radical anions formed in DMSO were measured by the voltammetric method. A quadratic Brønsted dependence of RTlnkH against pKa of phenols was observed. The intrinsic activation barrier ΔG0‡ calculated on the basis of the known pKa value for the conjugate acid ArH. of the anthracene radical anion is the same as for the reaction in DMF. The homolytic bond dissociation energy (for ArH.→Ar+H.) was also found to be the same as in DMF. The results obtained are in full agreement with theoretical predictions for protonation of radical anions forming C—H acids, described as the concerted electron and H atom transfer. Copyright © 2003 John Wiley & Sons, Ltd.
Ortho effect and steric inhibition of resonance: basicities of methyl‐substituted acetophenones
Authors: Otyepková Eva , Nevěčná Tat'jana , Kulhánek Jiří , Exner Otto 
Published: September 2003

AbstractThe basicity of 12 methyl‐substituted acetophenones was measured spectrophotometrically in 46–90 vol.% sulfuric acid. The acidity function was constructed and the pKa values were calculated by a new algorithm proposed by Pytela. The substituent effects were divided into polar and steric, assuming that the former are approximately equal in the ortho and para positions. Polar effects of the methyl group bring about stronger basicity as expected; the effect is more intense than the acid weakening in equally substituted benzoic acids. Steric effects of ortho methyl groups are base strengthening. This is not due to steric inhibition of resonance since the conformation remains planar in most derivatives. Two ortho methyl groups are necessary to distort the planarity; their steric effect is more than doubled compared with one methyl group. These results do not agree with the common idea of twisted conformations with gradually increasing twisting angle but are better rationalized by the existence of two groups of derivatives, planar and non‐planar. Copyright © 2003 John Wiley & Sons, Ltd.
Aromaticity and antiaromaticity: what role do ionic configurations play in delocalization and induction of magnetic properties?
Authors: Shurki Avital , Hiberty Philippe C. , Dijkstra Fokke , Shaik Sason 
Published: September 2003

AbstractCmHm (m= 4, 6, 8) species are analyzed in Dmh and D(1/2)mh geometries by means of valence bond (VB) calculations. The fundamental factors that distinguish aromatic and antiaromatic modes of electron delocalization are elucidated by analysis of the mixing between the covalent‐state and ionic structures that distribute the electrons in all possible modes available in the cycle. The major difference found is that, by contrast to the aromatic species where all the ionic structures mix into the covalent state, in the antiaromatic species the set of diagonal‐ionic structures is excluded from mixing with the covalent‐state, owing to its fundamental symmetry features. This exclusion of covalent–ionic mixing is expressed at the most fundamental building blocks of the wavefunction; the spin‐alternant state. The spin‐alternant state is a resonance hybrid of the two spin‐alternant determinants. This resonance hybrid will support a collective motion of the pπ‐electrons around the perimeter of the ring only if ionic structures can mix to mediate the electronic flow. It is shown that in aromatic species all the ionic structures mix and sustain a continuous electronic flow around the ring perimeter. By contrast, owing to the exclusion of the diagonal‐ionic structures in antiaromatic compounds, the electronic flow in antiaromatic species is interrupted. Symmetry and angular momentum analyses of the ground state in the presence of an external magnetic field show that the properties of the spin‐alternant state can qualitatively describe the magnetic properties of the two classes. The continuous flow of π‐electrons mediated by the ionic structures of aromatic species is responsible for the enhanced diamagnetism of these species. By contrast, paramagnetic π‐ring current in antiaromatic species becomes possible only in the presence of the magnetic field that allows the mixing of the otherwise excluded ionic structures. Copyright © 2003 John Wiley & Sons, Ltd.
Potential‐controlled coordination of coumarin to an Au(210) electrode surface
Authors: Iannelli Anna , Lipkowski Jacek 
Published: September 2003

AbstractAdsorption of coumarin on an Au(210) single‐crystal electrode was investigated using chronocoulometry and phase‐sensitive a.c. voltammetry. The adsorption parameters, such as the relative Gibbs surface excess, the Gibbs energies of adsorption and the electrosorption valencies, were calculated. The results suggest that coumarin molecules assume a flat, π‐bonded orientation on the Au(210) surface. The zero coverage Gibbs energy of adsorption at the potential of maximum adsorption is −42 kJ mol−1, which is a value typical of chemisorption. The adsorption of coumarin on the Au(210) surface was compared with adsorption at the (111) and (100) planes of gold. Copyright © 2003 John Wiley & Sons, Ltd.
Role of CH···O hydrogen bonds in the ionic complexes of 1,8‐bis(dimethylamino)naphthalene
Authors: Wozniak Krzysztof , Mallinson Paul R. , Smith Garry T. , Wilson Chick C. , Grech Eugeniusz 
Published: September 2003

AbstractOn the basis of experimental charge density distributions in a series of ionic complexes of 1,8‐bis(dimethylamino)naphthalene (DMAN) with four different acids, 1,2,4,5‐benzenetetracarboxylic acid (pyromellitic acid), 4,5‐dichlorophthalic acid, dicyanoimidazole ando‐benzoic sulfimide dihydrate (saccharin), the role of minor CH···O hydrogen bonds was analysed. We propose a multicentre model of hydrogen bonding in proton sponges {[Me2NH···.NMe2]+··· Xδ−}. It appears that weak interactions of electronegative atoms with the nearest methyl hydrogen atoms can influence the location of the proton in the intramolecular {NH···N}+hydrogen bridge. In the case of CH···O hydrogen bonds, the amount of electron density in the donor CH bonds involved in hydrogen bonding is slightly larger than that in those CH from the same methyl group which are not involved in hydrogen bonding. Numerical values of the Laplacian follow a reverse relation (they are smaller for the donor CH bonds). Both of these critical point parameters (rho and Laplacian) are linearly dependent on the length of interaction line. An increase in the amount of electron density in the H···O hydrogen bonding is associated with an increase in electron density in the donor C(methyl)H donor bond, which confirms the mainly ionic nature of such weak hydrogen bonds. Copyright © 2003 John Wiley & Sons, Ltd.
Influence of solvent polarity on the stereoselectivity of the uncatalyzed [4+2] cycloaddition of cyclopentadiene to an N,N′‐fumaroyl bis‐(six‐membered ring [(2R)‐10a‐homobornane‐10a,2‐sultam])
Authors: Pia̧tek Anna , Chapuis Christian , Jurczak Janusz 
Published: September 2003

AbstractA new six‐membered ring (2R)‐bornane‐10a,2‐sultam was tested as chiral auxiliary for the [4+2] cycloaddition of cyclopentadiene to the bis‐fumaroyl derivative (−)‐1f and shows under chelating conditions similar complete selectivity to Oppolzer's sultam. Inversion of the π‐face selectivity is nevertheless observed under uncatalyzed conditions under the influence of solvent polarity, varying from 82% de for the (2R,3R) cycloadduct 2f in trifluoroethanol to 70% de in favour of the (2S,3S) diastereoisomer in hexane as solvent. A predictive linear correlation is observed between the stereoselectivity and the solvent parameters according to the Abboud–Abraham–Kamlet‐Taft model. PM3 calculations allowed a rationalization of these results based on the transition‐state dipole moment. Illustrated by an x‐ray analysis of cycloadduct (2S,3S)‐2f, the main structural differences and influences in terms of steric and stereoelectronic factors are discussed by comparison of the five‐ versus six‐membered ring homologues. Copyright © 2003 John Wiley & Sons, Ltd.
The emergence of a new paradigm in ape language research
Authors: Shanker Stuart G. , King Barbara J. 
Published: September 2003

In recent years we have seen a dramatic shift, in several different areas of communication studies, from an information-theoretic to a dynamic systems paradigm. In an information processing system, communication, whether between cells, mammals, apes, or humans, is said to occur when one organism encodes information into a signal that is transmitted to another organism that decodes the signal. In a dynamic system, all of the elements are continuously interacting with and changing in respect to one another, and an aggregate pattern emerges from this mutual co-action. Whereas the information-processing paradigm looks at communication as a linear, binary sequence of events, the dynamic systems paradigm looks at the relation between behaviors and how the whole configuration changes over time.One of the most dramatic examples of the significance of shifting from an information processing to a dynamic systems paradigm can be found in the debate over the interpretation of recent advances in ape language research (ALR). To some extent, many of the early ALR studies reinforced the stereotype that animal communication is functional and stimulus bound, precisely because they were based on an information-processing paradigm that promoted a static model of communicative development. But Savage-Rumbaugh's recent results with bonobos has introduced an entirely new dimension into this debate. Shifting the terms of the discussion from an information-processing to a dynamic systems paradigm not only highlights the striking differences between Savage-Rumbaugh's research and earlier ALR studies, but further, it sheds illuminating light on the factors that underpin the development of communication skills in great apes and humans, and the relationship between communicative development and the development of language.
What Front‐Line CBO Staff Can Tell Us About Culturally Anchored Theories of Behavior Change in HIV Prevention for Asian/Pacific Islanders
Authors: Yoshikawa Hirokazu , Wilson Patrick A. , Hsueh JoAnn , Rosman Elisa A. , Chin John , Kim Jennifer H. 
Published: September 2003

AbstractFew rigorously tested primary prevention programs have been developed to prevent HIV infection among immigrant communities in the United States. This is in part because of the lack of culturally specific behavioral theories that can inform HIV prevention for immigrant communities in the United States. This article aims to develop such theories for a population—Asian/Pacific Islanders (A/PIs) immigrant communities—who have been overlooked in theory development and program evaluation. Frontline community‐based organization (CBO) peer educators, an underutilized source of expertise regarding cultural factors specific to HIV infection among A/PI communities, are the sample of study Asian/Pacific Islander peer educators working at an urban AIDS service organization devoted to health promotion for this population; (N=35). They were interviewed to examine (1) detailed narratives describing instances of behavior change and (2) culturally anchored theories of behavior change which the narratives imply. Theories of the influence of positive cultural symbols on the taboo of HIV/AIDS, moderators of the effectiveness of social network influences on behavior change, and setting‐ and community‐level processes predicting HIV risk behavior were implicit in the peer educators' narratives. Implications for future research, methodology and prevention practice are discussed.