bluuebunny/crossref_metadata_2025_split huggingface dataset:
An optical probe for local ion temperature measurements in a plasma
Authors: Kiss'ovski Zh. , Bohmeyer W. , Fussmann G. 
Published: December 2003

AbstractLocal measurements of the ion temperature and the spectral emissivity have been performed in the magnetized plasma of the PSI‐2 device using an optical probe. The proper operation of the probe could be demonstrated. The probe collects the light emission from a small separated plasma volume thus enabling to determine the ion temperature from Doppler‐broadening of suited spectral lines. In addition to the technical features stray light and finite Larmor radii effects ‐ limiting the spatial resolution ‐ are discussed. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural Studies on Hydrogen‐Bonding Receptors for Barbiturate Guests That Use Metal Ions as Allosteric Inhibitors
Authors: Al‐Sayah Mohammad H. , McDonald Robert , Branda Neil R. 
Published: December 2003

AbstractReceptor 1 was designed to bind barbiturate substrates through a six‐point hydrogen‐bonding motif only in the absence of metal allosteric cofactors. It was predicted that the binding of metal ions by bipyridine ligands in 1 would result in a geometric change in the receptor to inhibit substrate recognition. However, receptor 1 showed minimal affinity for the barbiturate guests even in the absence of the metal. Binding studies on model compounds 2, 3, 5, and 6 revealed that the inactivity of 1 is due to an intramolecular hydrogen bond between the N−H donor groups and the nitrogen atoms on the first heterocycle of the bipyridine ligands. This intramolecular hydrogen‐bonding was eliminated by altering the position of the tether between the bipyridine ligands and the active site to produce receptor 7. Consequently, the high affinity exhibited by 7 for the barbiturate substrate (Ka = 2.8±0.7 × 103 M−1 in 9:1 CD2Cl2/CD3CN) was significantly reduced by the addition of ZnII ions as a negative allosteric co‐factor. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Quaternary Ammonium‐Supported Scavenger Reagents for Acids and Electrophiles
Authors: Ghanem Noha , Martinez Jean , Stien Didier 
Published: December 2003

AbstractThe present article describes how we devised new quaternary ammonium‐supported quench reagents (TAMA‐Cl and BAX‐sulfate) for scavenging acids and excess electrophiles from crude reaction mixtures. TAMA‐Cl is liquid at room temperature, but is very glutinous and has to be used in aqueous solution. It removes unchanged electrophiles very efficiently. An aqueous preparation of TAMA‐Cl may be easily added in automated syntheses, and high‐throughput phase‐separation techniques should allow purification of scavenger‐containing reaction mixtures. However, workup with TAMA‐Cl is more complex than simple filtration. Recognizing this major advantage of solid‐phase syntheses, we designed BAX‐sulfate, a highly crystalline scavenger reagent that allows reaction workup to be simplified to a single filtration and evaporation of solvent. BAX‐sulfate reacts with electrophiles, quenches acids and precipitates quantitatively when diethyl ether is added. It even precipitates from methanol solutions. With BAX‐sulfate the workup stage uses simple filtration to make crude separations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Phthalocyaninatoindium(III) Acetylacetonates for Nonlinear Optics
Authors: Youssef Tamer Ezzat , O’Flaherty Sean , Blau Werner , Hanack Michael 
Published: December 2003

AbstractThe monomeric octaethylhexyl‐ and tetra‐tert‐butyl‐substituted phthalocyanines 3 and 12 with axial acetylacetonate as ligands were synthesized and characterized, in order to compare their optical limiting properties with the state‐of‐the‐art molecule [tetra‐(tert‐butyl)phthalocyaninato]indium chloride (tBu)4PcInCl (1a) and the phthalocyanines 1b−f. In addition, the trimer 17 was also synthesized (as a mixture of isomers). The synthesis of 3, 12 and 17 was carried out by refluxing the corresponding metal‐free phthalocyanines, (tBu)4PcH2 (2), (RO)8PcH2 (6) (R = 2‐ethylhexyl) and the trimer 16 with an excess of In(acac)3 in DMF. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthetic Studies on Pandanus Alkaloids: From Norpandamarilactonines to Pandamarilactonines, a Proof of Their Configurational Instability
Authors: Blanco Pilar , Busqué Felix , de March Pedro , Figueredo Marta , Font Josep , Sanfeliu Elena 
Published: December 2003

AbstractThe ethyl carbamate of norpandamarilactonine‐A was prepared in an enantiomerically pure form starting from (S)‐prolinol. Deprotection of the amine functionality rendered both diastereomeric norpandamarilactonines as racemates, which were used as synthetic precursors of pandamarilactonine‐A and ‐B. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
An Investigation on the Synthesis of New Molecular Architectures from the Cyclotrimerisation of exo‐ and endo‐Benzotricyclo[4.2.1.02,5]nonene
Authors: Dastan Arif , Uzundumlu Eren , Balci Metin , Fabris Fabrizio , Lucchi Ottorino De 
Published: December 2003

AbstractWe have performed an investigation on the cyclotrimerisation of molecules having exo‐ and endo‐benzotricyclo[4.2.1.02,5]nonene skeletons (3 and 4) with the aim of producing their respective cyclotrimers 2 that feature unusual geometries and electronic properties. Activation towards the cyclotrimerisation reaction was performed using the vic‐bromostannyl vinyl derivatives and was accomplished under copper‐mediated or palladium‐catalysed reaction conditions. While the exo isomer 3 proved to be quite reactive and afforded variable amounts of the syn and anti cyclotrimers, the endo isomer 4 turned out to be quite resistant to cyclotrimerisation because of steric hindrance. Only dimers and acyclic trimers were obtained from reactions using this substrate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Structural Homology and Dynamic Variation in a Series of Porphyrin Bipyridinium Receptors and Their [2]Catenanes
Authors: Gunter Maxwell J. , Jeynes Tyrone P. , Turner Peter 
Published: December 2003

AbstractWe describe the successful synthesis of the porphyrin [2]catenanes, which completes a set of six structures where the length of the polyethylene glycol strap over the porphyrin is regularly increased from diethylene to triethylene to tetraethylene, and the central electron‐donor component is either hydroquinol‐ or naphthoquinol‐based. In the synthetic route to the strapped porphyrin precursors, co‐formation of “straight” and “twisted” atropisomers in the longer strapped derivatives, and dimeric and higher oligomeric structures for the shorter straps, has been observed. Catenation results in only a single [2]catenane in each case. X‐ray crystal structures of two representative strapped porphyrins are described. For each of the untwisted singly‐strapped porphyrins, there is significant binding of paraquat within the cavity formed by the strap, and the binding constants range over about two orders of magnitude. For the catenanes, in each case the overall structural motif is similar to that previously observed for related members of the series. The temperature‐dependent dynamic properties of the catenanes have been examined by 1H NMR methods, and the rates of rotation increase from 50 to 25 000 to 340 000 s−1 at room temperature as the length of the strap increases by one ethylene glycol unit on each side. For the similarly sized naphthoquinol derivatives, the rotation rates are reduced by many orders of magnitude, ranging from essentially zero to 10 to 100 times per second at 25 °C through the same increase in chain length as for the hydroquinol analogues. The rates for a second process described as “out, turn around and in again”, range from 2 to 400 to 110 000 s−1 at 25 °C in this naphthoquinol porphyrin series. The electronic spectra of the catenanes themselves do not show any significantly enhanced charge‐transfer bands over the hydroquinol counterparts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Deprotonation‐Triggered Heavy‐Halogen Migrations as a Key to the Structural Elaboration of 2,2‐Difluoro‐1,3‐benzodioxole
Authors: Gorecka Joanna , Leroux Frédéric , Schlosser Manfred 
Published: December 2003

AbstractAlthough proton abstraction from the 4‐position of 2,2‐difluoro‐1,3‐benzodioxole occurs with exceptional ease, lithiation of the more‐remote 5‐position can only be brought about if no oxygen‐adjacent site remains unoccupied. Thus, unlike 4‐bromo‐2,2‐difluoro‐1,3‐benzodioxole (1), (7‐bromo‐2,2‐difluoro‐1,3‐benzodioxol‐4‐yl)triethylsilane (5b) does react with lithium diisopropylamide to generate an intermediate that isomerizes instantaneously by heavy‐halogen migration. Upon neutralization and carboxylation, 5‐bromo‐2,2‐difluoro‐1,3‐benzodioxole (8) and 5‐bromo‐2,2‐difluoro‐1,3‐benzodioxole‐4‐carboxylic acid (3) are formed nearly quantitatively. A similar basicity gradient‐driven heavy‐halogen migration can be accomplished starting from 2,2‐difluoro‐4,7‐diiodo‐1,3‐benzodioxole (11). These results procure a deeper insight in the acidifying effects of fluoroalkoxy groups and their distance dependence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Copolymerized polymeric surfactants: Characterization and application in micellar electrokinetic chromatography
Authors: Akbay Cevdet , Gill Nicole L. , Agbaria Rezik A. , Warner Isiah M. 
Published: December 2003

AbstractAn achiral monomeric surfactant (sodium 10‐undecenyl sulfate, SUS) and a chiral surfactant (sodium 10‐undecenoyl L‐leucinate, SUL) were synthesized and polymerized individually to form poly‐SUS and poly‐SUL. These surfactants were then copolymerized at various molar ratios to produce a variety of copolymerized surfactants (CoPSs), possessing both achiral (sulfate) and chiral (leucinate) head groups. The CoPSs, poly‐SUS, poly‐SUL, and sodium dodecyl sulfate were characterized using several analytical techniques. The aggregation numbers of the polymeric surfactants and the partial specific volumes were determined by the use of fluorescence quenching and density measurements, respectively. These polymeric surfactants were investigated as novel pseudostationary phases in micellar electrokinetic chromatography (MEKC) for the separation of chiral and achiral solutes. Solute hydrophobicity was found to have major influence on the MEKC retention of alkyl phenyl ketones. In contrast, hydrogen‐bonding ability of benzodiazepines is the major factor that governs their retention, but hydrophobicity has an insignificant effect on MEKC retention of benzodiazepines.
Characterization of antithrombin III from human plasma by two‐dimensional gel electrophoresis and capillary electrophoretic methods
Authors: Kremser Leopold , Brückner Andrea , Heger Andrea , Grunert Tom , Buchacher Andrea , Josic Djuro , Allmaier Günter , Rizzi Andreas 
Published: December 2003

AbstractThe isoforms distribution of the glycoprotein antithrombin III (ATIII) derived from human plasma was investigated by means of isoelectric focusing (IEF) in polyacrylamide gels with immobilized pH gradients (IPG) and two‐dimensional gel electrophoresis (2‐DE) as well as capillary electrophoretic methods. It turned out that the presence of high concentrations of chaotropics (urea, thiourea) and zwitterionic detergents (3‐[(3‐cholamidepropyl)dimethylammonio]‐1‐propanesulfonate (CHAPS)) was decisive for attaining good resolution of the protein isoforms. Resolution by IPG‐IEF was obtained with excellent reproducibility and pI differences down to 0.01 pH units could be distinguished. ATIII‐α and ATIII‐β‐fractions preseparated by heparin affinity chromatography showed an analogous but shifted spot pattern consisting each of one major and three minor isoforms. The main isoforms of ATIII‐α and ATIII‐β exhibit pI values of 5.18 and 5.32, respectively, both values determined in the presence of high concentrations of urea. The pI difference of 0.14 pH units correspond to the effect of two sialic acids absent in ATIII‐β. The formation and occurrence of ATIII dimers and trimers turned out to be dependent on the sample preparation. The results obtained by 2‐DE were compared with those of capillary zone electrophoresis (CZE) and capillary IEF (CIEF). Quantitative analysis regarding the CZE separated isoforms of plasma derived ATIII yielded a content of about 70% ATIII‐α main isoform and about 6.6% of ATIII‐β. The pI values of ATIII determined by CIEF with internal calibration were in fair agreement with the pI values of the main isoforms achieved with 2‐DE.
Characterization of surfactant and phospholipid vesicles for use as pseudostationary phases in electrokinetic chromatography
Authors: Pascoe Robert J. , Foley Joe P. 
Published: December 2003

AbstractThe physical, electrophoretic and chromatographic properties (mean diameter, electroosmotic flow, electrophoretic mobility, elution range, efficiency, retention, and hydrophobic, shape, and chemical selectivity) of three surfactant vesicles and one phospholipid vesicle were investigated and compared to a conventional micellar pseudostationary phase comprised of sodium dodecyl sulfate (SDS). Chemical selectivity (solute‐pseudostationary phase interactions) was discussed from the perspective of linear solvation energy relationship (LSER) analysis. Two of the surfactant vesicles were formulated from nonstoichiometric aqueous mixtures of oppositely charged, single‐tailed surfactants, either cetyltrimethylammonium bromide (CTAB) and sodium octyl sulfate (SOS) in a 3:7 mole ratio or octyltrimethylammonium bromide (OTAB) and SDS in a 7:3 mole ratio. The remaining surfactant vesicle was comprised solely of bis(2‐ethylhexyl)sodium sulfosuccinate (AOT) in 10% v/v methanol, and the phospholipid vesicle consisted of 1‐palmitoyl‐2‐oleyl‐sn‐glycero‐3‐phosphocholine (POPC) and phosphatidyl serine (PS) in 8:2 mole ratio. The mean diameters of the vesicles were 76.3 nm (AOT), 86.9 nm (CTAB/SOS), 90.1 nm (OTAB/SDS), and 108 nm (POPC/PS). Whereas the coefficient of electroosmotic flow (10−4 cm2 V−1 s−1) varied considerably (1.72 (OTAB/SDS), 3.77 (CTAB/SOS), 4.05 (AOT), 5.26 (POPC/PS), 5.31 (SDS)), the electrophoretic mobility was fairly consistent (−3.33 to −3.87×10−4 cm2 V−1 s−1), except for the OTAB/SDS vesicles (−1.68). This resulted in elution ranges that were slightly to significantly larger than that observed for SDS (3.12): 3.85 (POPC/PS), 8.6 (CTAB/SOS), 10.1 (AOT), 15.2 (OTAB/SDS). Significant differences were also noted in the efficiency (using propiophenone) and hydrophobic selectivity; the plate counts were lower with the OTAB/SDS and POPC/PS vesicles than the other pseudostationary phases (≤ 75 000/m vs. > 105 000/m), and the methylene selectivity was considerably higher with the CTAB/SOS and OTAB/SDS vesicles compared to the others (ca. 3.10 vs. ≤ 2.6). In terms of shape selectivity, only the CTAB/SOS vesicles were able to separate all three positional isomers of nitrotoluene with near‐baseline resolution. Finally, through LSER analysis, it was determined that the cohesiveness and hydrogen bond acidity of these pseudostationary phases have the greatest effect on solute retention and selectivity.
Nonaqueous capillary electrophoretic separation of polyphenolic compounds in wine using coated capillaries at high pH in methanol
Authors: Demianová Zuzana , Sirén Heli , Kuldvee Ruth , Riekkola Marja‐Liisa 
Published: December 2003

AbstractNonaqueous capillary electrophoretic separation of a group of flavonoids (quercetin, myricetin, catechin, epicatechin) and resveratrol in wine was investigated in methanol at high pH. Malonate background electrolyte (pH* 13.5, ionic strength I = 14.2 mmol/L) provided highly repeatable separations of the analytes. Tests of untreated and coated (poly(glycidylmethacrylate‐co‐N‐vinylpyrrolidone)) capillaries showed the analysis to be faster (6.5 min vs. 25 min) and the repeatability better in the coated capillaries. The coating procedure was simple and highly repeatable and the coating was stable during 40–45 runs. Determination of the last migrating peaks (epicatechin, resveratrol and catechin) was achieved merely by evaporating the wine samples and reconstituting the residue in methanol. For determination of the first migrating peaks (quercetin and myricetin) the samples were submitted to solid‐phase extraction in C8 cartridges.
Proteomic analysis of pancreatic ductal carcinoma cells treated with 5‐aza‐2'‐deoxycytidine
Authors: Cecconi Daniela , Astner Hubert , Donadelli Massimo , Palmieri Marta , Missiaglia Edoardo , Hamdan Mahmoud , Scarpa Aldo , Righetti Pier Giorgio 
Published: December 2003

AbstractA pancreatic adenocarcinoma cell line (PaCa44), which contains, among other alterations, a methylated p16 promoter, was treated with a chemoterapeutic agent, 5‐aza‐2'‐deoxycytidine (DAC), in order to evaluate the effect of this drug on cell growth and protein expression. Cell proliferation was strongly inhibited by a 24 h DAC treatment and this inhibition lasted for at least 10 days. Master maps of control and treated PaCa44 cells were generated by analysis with the PDQuest software. The comparison between such maps showed up‐ and downregulation of 45 polypeptide chains, of which 32 were downregulated and 13 upregulated, out of a total of 700 spots detected by a medium‐sensitivity stain, micellar Coomassie Brilliant Blue. Fingerprinting by mass spectrometry analysis enabled the identification of 36 of these spots. Among the major changes in DAC‐treated cells: cofilin and profilin 1 are silenced; coactosin, peptidyl‐propyl cis‐trans isomerase A and cystatin B are decreased by 22, 16‐ and 15‐fold, respectively; stress‐70 protein, superoxide dismutase and protein disulfide isomerase A3 are increased by 13‐, 11‐, and 5‐fold, respectively. The significance of some of these major changes is discussed.
Physical fitness and the stress process
Authors: Ensel Walter M. , Lin Nan 
Published: December 2003

AbstractIn the current paper we focus on the role of physical fitness in the life stress process for both psychological and physical well‐being. The major research question posed in the current study is: Does physical fitness deter distress in a model containing the major components of the life stress process? That is, do individuals who exercise show higher levels of well‐being than those that do not exercise? Is this relationship independent of the stress they experience and the resources they possess? Using data from a representative community sample, the current study finds that physical fitness is directly related to both psychological and physical distress. The more a person exercises, the less psychological and physical symptoms he or she manifests. Physical fitness is associated with decreased distress. This finding holds up, even when stressors and psychosocial resources are included in the model. While physical fitness was not found to mediate the effects of stressors on distress, there was some evidence of a moderating effect of fitness in the stressor–distress relationship, both for psychological and for physical distress. That is, fitness served to buffer the effects of stressors on both psychological and physical distress. In addition, physical fitness is associated with psychological resources that, in turn, are associated with lower levels of distress. The more a person exercises, the greater the self‐esteem. Thus, in addition to directly deterring distress, physical fitness was found to have the potential to indirectly deter distress through its positive association with the level of psychological resources (i.e., self‐esteem) that individuals possess. These and other findings are discussed in the context of the life stress paradigm. Implications for future stress research are presented. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 81–101, 2004.
Change in sense of community: An empirical finding
Authors: Loomis Colleen , Dockett Kathleen H. , Brodsky Anne E. 
Published: December 2003

AbstractThis study investigated changes in students' psychological sense of community (SOC) under two conditions of external threat against their urban, historically Black, public nonresidential university in a U.S. mid‐Atlantic city. Two independent stratified random samples (N = 801 and N = 241) consisting of undergraduate and graduate women (61%) and men (39%)—predominantly of color—averaging 29 years of age completed the Sense of Community Index (SCI; Perkins, Florin, Rich, Wandersman, & Chavis, 1990). During the first assessment there was an external threat to the university community that was not present 20 months later during the second assessment. In this cross‐sectional design, an analysis of covariance (ANCOVA) revealed support for the hypothesis that SOC would be higher when a threat was present than when it was absent ( p < .01). © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 1–8, 2004.
Neighborhoods and neighbors: Do they contribute to personal well‐being?
Authors: Farrell Susan J. , Aubry Tim , Coulombe Daniel 
Published: December 2003

AbstractThe present study examined the relationship between characteristics of neighborhoods (with set physical boundaries and relatively homogeneous populations) and personal well‐being as mediated by sense of community and neighboring behavior. A randomly selected representative sample of 345 residents living in non‐apartment dwellings in Winnipeg, Canada, completed a mail survey that included created measures of neighboring and sense of community and the General Health Questionnaire. Results demonstrated that sense of community mediates the relationship between neighborhood stability (as defined by the marital status and mobility) and residents' well‐being. The frequency of engaging in neighboring behavior was not directly predictive of residents' sense of personal well‐being, but was predictive of increased sense of community. Consistent with previous research, findings highlight the importance of building a sense of community among residents in a neighborhood. Implications of findings for neighborhood planning are discussed. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 9–25, 2004.
Prediction of gas chromatographic retention times of capillary columns of different inside diameters
Authors: Aryusuk Kornkanok , Krisnangkura Kanit 
Published: December 2003

AbstractThe retention times (t R) of n‐alkanes (C16–C22) eluted from capillary columns of different diameters are accurately predicted by using the equation proposed by Krisnangkura et al. (J. Chromatogr. Sci. 1997, 35, 329–332). The numerical values of four thermodynamically related constants (a, b, c, and d) of the BP‐1 (100% dimethylpolysiloxane) capillary column (0.32 mm ID×25 m, film thickness, 0.25 μm) are –6.169, –0.512, 226.98, and 410.30, respectively. For columns of the same stationary phase but of different inside diameters and film thickness, accurate tR values can be predicted by using the same numerical values of the last three constants but the first constant (a) is changed by the difference in the natural logarithm of the column phase ratios (β). All the derived numerical values of each column were tested with FAMEs and with n‐alkanes in temperature‐programmed GC (TPGC). All the predicted tR values agree well with the experimental values. About 77% of the TPGC data have errors lower than 0.5% and the largest value is –1.04%.