bluuebunny/crossref_metadata_2025 huggingface dataset:
Derivatisation of Pyrogallarenes
Authors: Åhman Antti , Luostarinen Minna , Schalley Christoph A. , Nissinen Maija , Rissanen Kari
Published: June 2005

Derivatisation of upper‐rim hydroxy groups of pyrogallarenes produced completely acylated and tosylated pyrogallarene derivatives. Mesitylation of pyrogallarene, however, resulted in a regioselective derivatisation of hydroxy groups, i.e. eight OH groups out of 12 were mesitylated. Crystal structures of the synthesised pyrogallarene derivatives indicate that completely substituted pyrogallarenes exist in a distorted crown conformation despite of the lack of stabilising intramolecular hydrogen bonds. In contrast, the partially substituted pyrogallarene adopts a boat conformation and has an open cavity for the inclusion of small guest molecules. © Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Shape‐Persistent Polyal Dendrimers – Facile Entry to Polyene and Polyyne Dendrimers
Authors: Narayanan Vijay , Sankararaman Sethuraman , Hopf Henning
Published: June 2005

Polyaldehyde (polyal) dendrimers were synthesized by a divergent iterative method using 1,3,5‐triethynylbenzene (1) as the core unit and 2‐bromo‐5‐tert‐butyl‐1,3‐benzenedicarbaldehyde (2) as the building block. The polyal dendrimers were further transformed into a new class of polyene and polyyne dendrimers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Photophysical Properties of a Highly Fluorescent Ditopic Ligand Based on 1,6‐Bis(ethynyl)pyrene as Central Aromatic Core
Authors: Leroy‐Lhez Stéphanie , Fages Frédéric
Published: June 2005

A simple synthetic route for the efficient preparation and purification of two regioisomers of a pyrene derivative containing two ethynyl groups―1,6‐ and 1,8‐bis(ethynyl)pyrene―is described. The former compound was used as a building block for the stepwise synthesis of a highly conjugated, ditopic bis(2,2'‐bipyridine) ligand (2) containing the pyrene nucleus at the central core. The fluorescence properties of ligand 2 are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The Decomposition of Transition Metal Alkyls Revisited: Surprising Wellspring of Novel Reagents for Organic Synthesis
Authors: Eisch John J. , Adeosun Adetenu A. , Dutta Somnath , Fregene Paul O.
Published: June 2005

A broad survey of both the simple and double decomposition modes of transition metal alkyls has been undertaken. From the two main processes of C–M bond rupture, homolysis, and β‐metal hydride elimination, the following modes of decomposition and types of useful reagents generated can be distinguished: 1) reductive decomposition of RnMEm–n to yield subvalent, carbene‐ or free‐radical‐like MEm–n, which can cleave π‐ or σ‐bonds by direct epimetallation; 2) β‐metal hydride elimination to produce hydrometallating agents; 3) combined reductive and β‐metal hydride eliminations to produce anionic, and hence more nucleophilic, epimetallating agents; 4) α‐metal hydride elimination thought to be involved in the transition state leading to C–C bond coupling from (RR'HC)2ME2 derivatives; 5) α,μ‐elimination from lithiated RHC(Li)–MEn–1, which produces alkylidenes, RHC=MEn–2, capable of ROMP catalysis; 6) metal–hydrogen metathesis, whereby sufficiently acidic C–H bonds become C–M bonds; 7) metal–metal metathesis, whereby RR'ME2 undergoes an equilibrating redistribution reaction to form R2ME2 and R'2ME2; 8) transfer epimetallation, in which epimetallation (point 1) is achieved with R2ME2 in one step by transfer of ME2 to the substrate with the concomitant loss of R groups; and 9) transfer epimetallation of olefins by R2TiE2 in hydrocarbons to produce titana(IV)cyclopropanes, which serve as active sites in Ziegler–Natta polymerization. In each situation, the reaction‐mechanistic features are analyzed in terms of existing experimental data and evidence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A General Method for the Preparation of Chiral TREN Derivatives
Authors: Pei Yuxin , Brade Katja , Brulé Emilie , Hagberg Lars , Lake, Fredrik , Moberg Christina
Published: June 2005

A general procedure for the preparation of C3‐symmetric TREN derivatives with backbone chirality has been developed. Stereo‐ and regioselective ring opening by ammonia of (S)‐N‐tosyl‐2‐isopropylaziridine, obtained starting from either the corresponding amino alcohol or amino acid, followed by deprotection of the amino groups afforded the parent chiral TREN compound in high overall yield. In addition to TREN compounds with primary amino groups, the synthetic method employed provides easy access to a variety of N,N',N''‐substituted derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cover Picture: First Asymmetric Synthesis of (+)‐Sordidin and (−)‐7‐epi‐Sordidin, Aggregation Pheromones of the Banana Weevil Cosmopolites sordidus (Eur. J. Org. Chem. 12/2005)
Authors: Enders Dieter , Breuer Irene , Nühring Anja
Published: June 2005

The cover picture shows the most important worldwide insect pest of banana plants, the banana weevil Cosmopolites sordidus (Germar). These long‐lived weevils lay their eggs in the rhizome of the plant. The larvae hatch and then feed and tunnel in the rhizome of the plant, weakening it and leading to the snapping of the rhizome at the ground level before the bunch is ripe. The first evidence for the depicted volatile male‐produced aggregation pheromones, sordidin and 7‐epi‐sordidin was supplied by Budenberg et al. in 1993. Details of the first asymmetric synthesis of the major pheromone compound, sordidin, and its C‐7‐epimer based on the SAMP/RAMP‐hydrazone methodology are described in the article by D. Enders et al. on p. 2677 ff.
Fast prototyping of hydrophobic disposable polymer support arrays for matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry of proteins by atmospheric molding
Authors: Muck Alexander , Nešněrová Petra , Pichová Iva , Svatoš Aleš
Published: June 2005

A fast protocol for prototyping hydrophobic disposable poly(alkyl methacrylate‐co‐methyl methacrylate) copolymer sample support arrays for matrix‐assisted laser desorption/ionization‐mass spectrometry (MALDI‐MS) of proteins by atmospheric molding is introduced. The sample support arrays were replicated by molding prepolymer alkyl methacrylate solutions into sandwich molds containing a micromachined silicon master, an aluminum spacer, and glass cover plates, followed by UV‐initiated in situ polymerization under atmospheric pressure. The fabrication procedure enables a simultaneous fabrication/modification of single‐use polymer arrays by a targeted selection of functional groups of the copolymerized monomers during molding. The one‐step modification during the fabrication is demonstrated for enhanced protein adsorption to the modified materials by introduction of hydrophobic butyl‐, dodecyl‐, and octadecyl groups to the polymer backbone without a need for additional surface coating or derivatization. The MALDI‐MS performance of the new polymer chips was tested for spectral measurements of bovine pancreas insulin, horse heart myoglobin, and bovine serum albumin. The protein adsorption to the new hydrophobic copolymer chips was studied for bovine pancreas trypsinogen; the sample desalting parameters, such as time and volume, were optimized for myoglobin as model proteins. A significant signal increase was achieved after efficient desalting of an insect δ11‐desaturase membrane protein fragment from a complex elution buffer (100 mM phosphate, 10 mM tris(hydroxyethyl)aminomethane, 0.5 M NaCl, and 10 mM ethylenediamine tetraacetic acid) on the poly(butyl methacrylate‐co‐methyl methacrylate) copolymer chip (monomer ratio 8:2 v/v) by simply washing the target zones. The new chips offer reduced sample manipulation and device fabrication times as well as simple operation.
Separation techniques hyphenated to electrospray‐tandem mass spectrometry in proteomics: Capillary electrophoresis versus nanoliquid chromatography
Authors: Pelzing Matthias , Neusüß Christian
Published: June 2005

Liquid chromatography (LC) nanoelectrospray‐tandem mass spectrometry (MS/MS) is a key technology for the study of proteomics, with the main benefit to the characterization of sensitive peptides from complex mixtures. Capillary electrophoresis coupled to mass spectrometry (MS) has been taken into consideration sporadically due to the highly efficient separation and ability to handle low sample amount, yet classified as being less sensitive with respect to analyte concentration. The limitation in capillary zone electrophoresis (CZE) injection volumes can be overcome by on‐line solid‐phase extraction (SPE). Such an on‐line SPE‐CZE system was explored in combination with an ion trap (IT) mass spectrometer. Thus, it was possible to inject more than 100 µL sample solution on to the CZE capillary. Concentration limits of detection as low as 100 amol/µL were demonstrated for a peptide standard. This SPE‐CZE‐microelectrospray ionization (ESI)‐MS/MS setup was compared directly to nanoLC/nanoESI using the same sample of a tryptic digest of bovine serum albumin (BSA) as a reference standard. Measurements were made on one IT mass spectrometer with identical acquisition parameters. Both chromatography systems enabled the separation and detection of low levels of peptides from a mixture of moderate complexity, with most peptides identified using both techniques; however, specific differences were obvious. The nanoLC‐MS is about five times more sensitive than the CZE‐MS, yet the difference was less pronounced than expected. The CZE‐MS technique showed reduced loss of peptides, especially for larger peptides (missed cleavages) and is about four times faster than the nanoLC‐MS approach.
Age‐dependent variations of cell response to oxidative stress: Proteomic approach to protein expression and phosphorylation
Authors: Miura Yuri , Kano Mayumi , Abe Kazuhiko , Urano Shiro , Suzuki Shozo , Toda Tosifusa
Published: June 2005

We investigated the protein profiles of variously aged rat astrocytes in response to oxidative stress. After H2O2‐exposure of cells at 100 µM for 30 min, the relative intensity of ten protein spots changed on two‐dimensional (2‐D) gels compared with control gels after silver staining. Matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) analysis after in‐gel digestion revealed that six of these spots corresponded to three kinds of proteins, each of which was composed of a protein and its modified form with a different isoelectric point (pI). These three proteins were identified as peroxiredoxins (PRDXs) II and III, and calpactin I light chain (p11). H2O2‐exposure increased the intensity of the spot with lower pI and simultaneously decreased that of the spot with higher pI for both PRDXs II and III. In addition, the expression of annexin VII, S‐adenosyl‐L‐homocysteine hydrolase, elongation factor II fragment (EF‐II), and adenosine deaminase was increased by H2O2‐exposure in astrocytes from variously aged rats. Using the Pro‐Q® Diamond staining, heat shock protein 60 kDa (Hsp 60) and α‐tubulin were observed to be phosphorylated upon H2O2‐exposure. While phosphorylation of α‐tubulin was correlated positively with age, the changes in abundance of ten protein spots as described above were independent of age. These results suggest that aging does not suppress the responses aimed at limiting injury and promoting repair brought about by severe oxidative stress, and might affect cell dynamics including the formation of microtubules.
Ampheristocystis, a Silurian (Lower Wenlock) eocrinoid (Echinodermata, Blastozoa) from Indiana
Authors: Frest T. J.
Published: June 2005

The enigmatic blastozoan echinoderm Ampheristocystis concentricus, based on four specimens from the upper part of the Osgood Member, Salamonie Dolomite (Upper? Llandovery–Lower Wenlock), southeastern Indiana, is most likely an eocrinoid. Supporting this assignment are the five basals(?), five symmetrical appendage facets (possibly bearing biserial brachiolar trunks) and details of the thecal plating (moderate number of semiregularly arranged thecal plates). Some features (poorly known subvective appendages and poreless thecal plates) could indicate paracrinoid affinities, and suggest that the classes Eocrinoidea and Paracrinoidea may be more closely related than indicated by current taxonomy. Whatever the class disposition, the genus is the youngest representative yet known. Placement in the Blastozoa, based on holoperipheral plate growth, morphology of the brachiole‐like appendages and peristome, among other features, is unequivocal. The sharply discriminated oral and thecal plating, and protuberant anal opening, are unusual features for either paracrinoids or eocrinoids. Separate familial status is advocated for Ampheristocystis, but the family is not assigned to an order. The oral surface of the genus, consisting of regular orals and suborals, and fixed ambulacrals, presents an arrangement unique among eocrinoids, but analogous to the tegmen of camerate crinoids and of the rhombiferan family Caryocrinitidae. Development of a regular tegmen, fairly regular thecal plating and elongate fusiform shape indicate Ampheristocystis is an evolutionarily convergent, aberrant blastozoan, perhaps competitive with the camerates that generally dominated Silurian echinoderm faunas, and with the contemporary, equally successful blastozoan Caryocrinites. Ampheristocystis is not closely associated with hard surfaces or debris piles, as are many Osgood echinoderms, but preferred soft silt or mud bottoms. Associated echinoderms include several diploporites, coronoids, a few large camerates (e.g. Eucalyptocrinites) and Caryocrinites. Two specimens have evidently decollated the stem; one retains a sizeable, crinoid‐like stem. Hence, it is presently unclear whether the life habits of this genus were more like that of the common Osgood diploporites or stemmed contemporaries such as Caryocrinites and Eucalyptocrinites. Alternatively, it could perhaps exploit both habits equally well. Copyright © 2005 John Wiley & Sons, Ltd.
Oligodendrocyte‐specific ceramide galactosyltransferase (CGT) expression phenotypically rescues CGT‐deficient mice and demonstrates that CGT activity does not limit brain galactosylceramide level
Authors: Zöller Inge , Büssow Heinrich , Gieselmann Volkmar , Eckhardt Matthias
Published: June 2005

Galactosylceramide (GalC) is the major sphingolipid of the myelin membrane. Mice lacking GalC due to ceramide galactosyltransferase (CGT) deficiency form unstable and functionally affected myelin and exhibit a progressive demyelination, accompanied by severe motor coordination deficits. In addition to oligodendrocytes, CGT is also expressed in other cells, e.g., neurons and astrocytes. We examined the possibility that lack of CGT in these cells contributes to the phenotype of CGT‐deficient mice. Toward this aim, we generated transgenic mice expressing CGT under the control of oligodendrocyte‐specific proteolipid protein (PLP) promoter and examined the possibility of a transgenic rescue of CGT‐deficient mice. CGT‐deficient mice expressing the PLP‐CGT transgene did not show any behavioral abnormalities, normal myelin structure, and MBP levels. CGT activity as well as GalC and sulfatide levels of rescued mice were not significantly different from wild‐type controls. Thus, transgenic rescue with the PLP‐CGT transgene was apparently complete. In contrast to wild‐type and rescued mice, PLP‐CGT transgenic mice on a wild‐type background exhibited significantly elevated CGT activity which directly correlated with an increase in non‐hydroxy fatty acid (NFA)‐GalC, but not α‐hydroxy fatty acid (HFA)‐GalC. HFA‐GalC decreased in adult transgenic mice, indicating that NFA‐GalC, but not HFA‐GalC levels are limited by CGT activity. As a consequence, the total amount of GalC is unchanged over a rather wide range of CGT expression levels in the mouse brain. Our results indicate that loss of CGT in oligodendrocytes is exclusively responsible for the myelin structural deficits, demyelination, and behavioral abnormalities in CGT‐deficient mice. © 2005 Wiley‐Liss, Inc.
Growth factor and cytokine regulation of chondroitin sulfate proteoglycans by astrocytes
Authors: Smith George M. , Strunz Celia
Published: June 2005

After injury to the adult central nervous system (CNS), numerous cytokines and growth factors are released that contribute to reactive gliosis and extracellular matrix production. In vitro examination of these cytokines revealed that the presence of transforming growth factor‐β1 (TGF‐β1) and epidermal growth factor (EGF) greatly increased the production of several chondroitin sulfate proteoglycans (CSPG) by astrocytes. Treatment of astrocytes with other EGF‐receptor (ErbB1) ligands, such as TGF‐α and HB‐EGF, produced increases in CSPG production similar to those observed with EGF. Treatment of astrocytes, however, with heregulin, which signals through other members of the EGF‐receptor family (ErbB2, ErbB3, ErbB4), did not induce CSPG upregulation. The specificity of activation through the ErbB1 receptor was further verified by using a selective antagonist (AG1478) to this tyrosine kinase receptor. Western blot analysis of astrocyte supernatant pre‐digested with chondroitinase ABC indicated the presence of multiple core proteins containing 4‐sulfated or 6‐sulfated chondroitin. To identify some of these CSPGs, Western blots were screened using antibodies to several known CSPG core proteins. These analyses showed that treatment of astrocytes with EGF increased phosphacan expression, whereas treatment with TGF‐β1 increased neurocan expression. Reverse transcription‐polymerase chain reaction (RT‐PCR) was used to examine the expression of these molecules in vivo, which result in increased expression of TGF‐β1, EGF‐receptor, neurocan, and phosphacan after injury to the brain. These data begin to elucidate some of the injury‐induced growth factors that regulate the expression of CSPGs which could be targeted in the future to modulate CSPG production after injury to the central nervous system. © 2005 Wiley‐Liss, Inc.
Flavonol glycosides and antioxidant capacity of various blackberry and blueberry genotypes determined by high‐performance liquid chromatography/mass spectrometry
Authors: Cho Mi Jin , Howard Luke R , Prior Ronald L , Clark John R
Published: June 2005

Flavonol glycoside composition and content in blueberry and blackberry extracts were determined using a high‐performance liquid chromatographic (HPLC) separation method coupled with photodiode array (PDA) and mass spectrometric (MS) detection. The hydrophilic antioxidant capacities of crude and fractionated flavonol extracts were also determined by the oxygen radical‐absorbing capacity (ORACFL) and photochemiluminescence (PCL) assays. Eight flavonols of quercetin and quercetin–sugar conjugates were identified in Kiowa blackberry, namely rutinoside, galactoside, methoxyhexoside, glucoside, pentoside, [6″‐(3‐hydroxy‐3‐methylglutaroyl)]‐β‐galactoside, glucosylpentoside and oxalylpentoside. Thirteen flavonols were detected in Ozarkblue blueberry. Of these, myricetin 3‐hexoside and 12 quercetin–sugar conjugates, namely rutinoside, galactoside, methoxyhexoside, glucoside, pentoside, glucosylpentoside, caffeoylglucoside, oxalylpentoside, rhamnoside, dimethoxyrhamnoside, acetylgalactoside and acetylglucoside, were identified. In Bluecrop blueberry, two additional quercetin–sugar conjugates were identified, namely glucuronide and caffeoylgalactoside. Quercetin glycosides accounted for 75% of total flavonols in the blueberry genotypes. Total flavonol contents ranged from 99 to 150 mg kg−1 for blackberries and from 192 to 320 mg kg−1 for blueberries. Quenching of peroxyl and superoxide anion radicals by the flavonol fractions ranged from 1.5 to 2.3 mmol Trolox equivalents (TE) kg−1 and from 0.5 to 0.7 mmol TE kg−1 respectively for blackberries and from 2.9 to 5.2 mmol TE kg−1 and from 0.8 to 1.4 mmol TE kg−1 respectively for blueberries. The HPLC method allowed for complete separation and identification of flavonols commonly found in blackberries, and blueberries. Our results showed that blueberry and blackberry genotypes varied significantly in flavonol content and antioxidant capacity. Even though total flavonol content did not correlate well with antioxidant capacity, their ability to scavenge peroxyl and superoxide anion radicals was apparent. Copyright © 2005 Society of Chemical Industry
Dough aeration and rheology: Part 1. Effects of mixing speed and headspace pressure on mechanical development of bread dough
Authors: Chin Nyuk L , Campbell Grant M
Published: June 2005

A laboratory‐scale Tweedy‐type mechanical dough development mixer was modified to monitor work inputs of dough during mixing through a computerised data acquisition system. Recorded torque showed a curve that increased to a peak about midway through mixing. Using this system, the effects of mixing speed and pressure on the development of doughs made from strong and weak flours mixed to a work input of 40 kJ kg−1 were studied. Mixing was characterized in terms of peak torque and torque at the end of mixing (end torque), and in terms of the number of blade revolutions at these two reference points. The peak torque and the end torque both increased with increasing mixing speed. The peak torque increased with increasing mixer headspace pressure, but the end torque did not. The number of blade revolutions to both the point of peak torque and to the end of mixing decreased with increasing mixing speed for both flours, implying dough development at higher speeds was more efficient. Increasing headspace pressure reduced the number of revolutions to the peak, but not to the end of mixing. These results provide evidence that achieving dough development is not independent of mixing speed in Tweedy‐type mixers, and that dough aeration, as affected by mixer headspace pressure, affects dough rheology and hence development in the mixer. Copyright © 2005 Society of Chemical Industry
Influence of dietary conjugated linoleic acid on the fatty acid composition and volatile compounds profile of heavy pig loin muscle
Authors: Pastorelli Grazia , Moretti Vittorio M , Macchioni Paolo , Lo Fiego Domenico P , Santoro Piero , Panseri Sara , Rossi Raffaella , Corino Carlo
Published: June 2005

This study evaluated the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition, chemical composition and volatile compounds profile of the longissimus dorsi muscle in Italian heavy pigs. The animals (97 kg) were randomly assigned to three diets varying in supplemental CLA (CON = 0 CLA, T1 = 2.5 g CLA kg−1 feed and T2 = 5.0 g CLA kg−1 feed) till the slaughtering at 172 kg. Samples of longissimus dorsi were analysed for chemical composition (moisture, protein and lipid content), fatty acid composition and volatile compounds. No significant differences were observed for proximate chemical composition. Dietary CLA showed limited effects on fatty acid composition of longissimus dorsi, with higher, but not significantly, amounts of saturated fatty acids in the treated groups than in the control group; both the cis‐9, trans‐11 and the trans‐10, cis‐12 isomers of CLA were increased in longissimus dorsi from pigs fed CLA. T1 and T2 pigs had a greater concentration of C16:0 and of C16:1 (P < 0.01) than CON. CLA diets tended to reduce C20:2 (P = 0.077) and C20:4 (P = 0.065) content in longissimus dorsi muscle. Diets containing higher amount of CLA were responsible for increased levels of volatile compounds in meat, but not at a significant level. Copyright © 2005 Society of Chemical Industry
The dark side of discounts: An inaction inertia perspective on the post‐promotion dip
Authors: Zeelenberg Marcel , Putten Marijke van
Published: June 2005

After a product has been on promotion, the sales of that product may temporarily decrease. This post‐promotion dip is normally explained in terms of forward buying or stockpiling. This article offers a third explanation in terms of brand switching. The results of two experiments show that after missing a discount on their regular brand, consumers may switch to another brand. Switching behavior is much more pronounced when a large discount is missed in comparison to when a small discount is missed. This finding is consistent with recent social psychological research on inaction inertia, and the results are discussed in relation to this phenomenon. © 2005 Wiley Periodicals, Inc.
Memory for advertising and information content: Comparing the printed page to the computer screen
Authors: Jones Marilyn Y. , Pentecost Robin , Requena Gabrielle
Published: June 2005

An experiment was used to test memory for two forms of information—ad copy (persuasive) and consumer information (nonpersuasive) presented in print and screen media. For both forms of information, print outperforms screen on recall but not on recognition. The results suggest that print information is easier to retrieve but also that screen information is available in memory. Differences between print and screen media are persistent and not readily explained by any of the obvious individual factors—comfort/familiarity, preference, and reading time. Other results with implications for marketing communication decisions show that brand name is poorly recalled from the screen relative to the printed page and that the nonpersuasive consumer information is better remembered than is persuasive ad information. © 2005 Wiley Periodicals, Inc.
A cognitive and behavioral hierarchical decision‐making model of college students' alcohol consumption
Authors: Shim Soyeon , Maggs Jennifer
Published: June 2005

This study examined college students' drinking behaviors from a consumer behavioral perspective. A consumer‐oriented, cognitive, and behavioral‐hierarchical decision‐making model was developed and tested with the use of structural equation modeling. Questionnaires were collected from undergraduate students ( n = 269) attending a large state university in the southwestern United States. Results indicated that personal values can serve as significant predictors of the attitudes college students have toward alcohol use, which in turn can predict intentions to drink. Results also indicated that intentions to drink are strongly related to actual alcohol consumption, and that gender‐predicted attitudes and alcohol use during the past month influences intentions to drink. However, the structure of the model was similar after controlling for gender differences in alcohol use and for the stability of past behavior. The model delineated the specific roles played by personal values (self‐actualizing values vs. social–hedonic values) and attitudes toward the physical and psychological consequences of drinking. Overall, social–hedonic values and psychological consequences predicted actual alcohol consumption far better than did self‐actualizing values and physical consequences, respectively. Theoretical and practical implications are discussed, and directions for future research are suggested. © 2005 Wiley Periodicals, Inc.
Advances and Limits in Copolymerization of Olefins with Conjugated Dienes
Authors: Boisson Christophe , Monteil Vincent , Thuilliez Julien , Spitz Roger , Monnet Christiane , Llauro Marie‐France , Barbotin Fanny , Robert Pierre
Published: June 2005

The field of the copolymerization of olefins with conjugated dienes has been investigated. While the insertion of butadiene is often limited with most catalyst systems designed for olefin polymerization, lanthanide metallocene catalysts insert butadiene with good efficiency. In the present paper, the preparation of a vast range of products including new polymers is reviewed.
Polymerization of Ethene and Longer Chained Olefins by Metallocene Catalysis
Authors: Kaminsky Walter , Piel Christian , Scharlach Katrin
Published: June 2005

Copolymers of ethene and longer chained 1‐olefins such as 1‐octene, 1‐decene, 1‐dodecene, 1‐octadecene and 1‐hexacosene with 8 to 28 carbon atoms were carried out using [Ph2C(2,7)‐ditertBuFlu)(Cp)]ZrCl2/MAO as catalyst. Precisely designed microstructures and activities up to 168 000 kgcopolymer/(molzirconocene·h·mol/lmonomer) can be obtained. There is a remarkable polymerization activity left even after a time of 4 hours. The incorporation of the longer chained 1‐olefins reaches 19 wt% and depends on the chain length and the concentration of the comonomer in the feed, the LLDPE materials prepared show melting points of 129 – 112 °C.
Activation Mechanisms of Trialkylaluminum in Alkali Metal Alkoxides or Tetraalkylammonium Salts / Propylene Oxide Controlled Anionic Polymerization
Authors: Carlotti Stéphane , Billouard Cyrille , Gautriaud Emilie , Desbois Philippe , Deffieux Alain
Published: June 2005

The anionic polymerization of propylene oxide (PO) initiated by alkali metal alkoxides is in non polar solvents a very slow and non controlled reaction process. Transfer reaction to monomer is predominant, allowing only the preparation of low molar masses PPO. The influence of the addition of trialkylaluminium to either an alkali metal alkoxide or a tetraalkylammonium salt used as initiator for PO polymerization in hydrocarbon media was investigated. A strong enhancement of the polymerization rate accompanied by a drastic decrease of the transfer reactions is observed, allowing the synthesis of PPO with well controlled molar masses. At constant monomer and alkali metal alkoxide concentrations, the polymerization rate increases with increasing trialkylaluminium concentration. Results indicate that the trialkylaluminium derivative is involved in the formation of two distinct complexes, one with the alkali metal alkoxide or the tetraalkylammonium salt and another one with the PO monomer which is strongly activated towards nucleophilic active species. Significant differences between the alkali metal and tetraalkylammonium based initiators are observed. In particular much less trialkylaluminum activator is needed with the ammonium salt to get the same rate of propagation and controlled polymerization.
Copolymerization of Cyclic Esters at the Living Polymer‐Monomer Equilibrium
Authors: Duda Andrzej , Libiszowski Jan , Mosnáček Jaroslav , Penczek Stanisław
Published: June 2005

This paper gives a short review of our findings related to the copolymerization of γ‐butyrolactone (B) and L,L‐lactide (L) with ϵ‐caprolactone (C) at or below B and L equilibrium concentrations in homopolymerization. We show, contrary to the commonly established opinions, that: (i) B effectively undergoes ring‐opening reaction and therefore is able to high molar copolymers formation containing up to 50 mol‐% repeating units derived from B and (ii) in conditions eliminating transesterification living poly(L) does initiate polymerization of C leading to poly(L)‐block‐poly(C) copolymer.
Novel Synthesis and Properties of Smart Core‐Shell Microgels
Authors: Leung Man Fai , Zhu Junmin , Harris Frank W. , Li Pei
Published: June 2005

A new method has been developed to prepare smart microgels that consist of well‐defined temperature‐sensitive cores with pH‐sensitive shells. The microgels were obtained directly from aqueous graft copolymerization of N‐isopropylacrylamide and N,N′‐methylenebisacrylamide from water‐soluble polymers containing amino groups such as poly(ethyleneimine) and chitosan. The gel diameters ranged from 300 to 400 nm with narrow size distribution. The unique core‐shell nanostructures exhibited tuneable responses to pH and temperature.
Synthesis of Core‐Shell Polyurethane‐Polydimethylsiloxane Particles by Polyaddition in Organic Dispersant Media: Mechanism of Particle Formation
Authors: Chambon Pierre , Cloutet Eric , Cramail Henri
Published: June 2005

Core‐shell polyurethane (PUR)‐polydimethylsiloxane (PDMS) particles were prepared by polyaddition between ethylene glycol and tolylene‐2,4‐diisocyanate in cyclohexane, used as the organic dispersant phase, in the presence of reactive hydroxy‐terminated polydimethylsiloxane steric stabilizers. The reaction extent and the PUR particle size, monitored by FTIR, 1H NMR, SEC, SEM and TEM techniques against time, were found a function of the PDMS concentration, functionality and molar mass. A mechanism of the polyurethane particle growth is proposed on the grounds of the kinetic investigation.
Control of the Colloidal Stability of Polymer‐Grafted‐Silica Nanoparticles Obtained by Atom Transfer Radical Polymerization
Authors: El Harrak Abdeslam , Carrot Géraldine , Oberdisse Julian , Jestin Jacques , Boué François
Published: June 2005

Polymer chains are grafted from silica nanobeads. The method consists in grafting first the initiator molecules on the silica surface. Then, the polymerization of styrene or n‐butyl methacrylate using Atom Transfer Radical Polymerization, is conducted. The nanoparticles are kept in solution during the whole process to avoid irreversible aggregation. The state of dispersion of the grafted silica nanoparticles is followed by Small Angle Neutron Scattering, as well as the quantity and the spatial organisation of the polymer. This is done during the functionalisation and the polymerization, but also after purification where free polymer chains are eliminated. This permits to reach a quantitative level of SANS analysis from these purified particles, which is compared to chemical data given by Size Exclusion Chromatography and Thermogravimetric analysis.
Variable field of view for spatial resolution improvement in continuously moving table magnetic resonance imaging
Authors: Hu Houchun H. , Madhuranthakam Ananth J. , Kruger David G. , Glockner James F. , Riederer Stephen J.
Published: June 2005

An approach is described in which the field of view (FOV) along the Y (right/left) phase encoding direction can be dynamically altered during a continuously moving table (CMT) coronal acquisition for extended FOV MRI. We hypothesize that with this method, regions of the anatomy exhibiting significantly different lateral widths can be imaged with a matching local FOVY, thereby improving local lateral spatial resolution. k‐space raw data from the variable‐FOV CMT acquisition do not allow simple Fourier reconstruction due to the presence of a mixture of phase encodes sampled at different ΔkY intervals. In this work, we employ spline interpolation to reregister the mixed data set onto a uniformly sampled k‐space grid. Using this interpolation scheme, we present phantom and peripheral contrast‐enhanced MR angiography results demonstrating an approximate 45% improvement in local lateral spatial resolution for continuously moving table acquisitions. Magn Reson Med 54:146–151, 2005. © 2005 Wiley‐Liss, Inc.
Liver iron concentration evaluated by two magnetic methods: Magnetic resonance imaging and magnetic susceptometry
Authors: Carneiro Antonio Adilton O. , Fernandes Juliana P. , de Araujo Draulio B. , Elias Jorge , Martinelli Ana L. C. , Covas Dimas T. , Zago Marco A. , Ângulo Ivan L. , St. Pierre Timothy. G. , Baffa Oswaldo
Published: June 2005

Quantification of liver iron concentration (LIC) is crucial in the management of patients suffering from certain pathologies that can produce iron overload, such as Cooley's anemia and hemochromatosis. All of these patients must control the level of iron deposits in their organs to avoid the toxicity of high LIC, which is potentially lethal. This paper describes experimental protocols for LIC measurement using two magnetic techniques: magnetic resonance imaging (MRI) and biomagnetic liver susceptometry (BLS). MRI proton transverse relaxation rate (R2) and image intensity, evaluated pixel by pixel, were used as indicators of iron load in the tissue. LIC measurement by BLS was performed using an AC superconducting susceptometer system. A group of 23 patients with a large range of iron overload (0.9 to 34.5 mgFe/gdry tissue) was evaluated with both techniques (MRI × BLS). A significant linear correlation (r = 0.89–0.95) was found between the LIC by MRI and by BLS. These results show the feasibility of using two noninvasive methodologies to evaluate liver iron store in a large concentration range. Both methodologies represent an equivalent precision. Magn Reson Med 54:122–128, 2005. © 2005 Wiley‐Liss, Inc.
Nonnvasive assessment of vascular architecture and function during modulated blood oxygenation using susceptibility weighted magnetic resonance imaging
Authors: Rauscher Alexander , Sedlacik Jan , Barth Markus , Haacke E. Mark , R. Reichenbach Jürgen
Published: June 2005

Susceptibility weighted imaging (SWI) is a BOLD‐sensitive method for visualizing anatomical features such as small cerebral veins in high detail. The purpose of this study was to evaluate high‐resolution SWI in combination with a modulation of blood oxygenation by breathing of air, carbogen, and oxygen and to directly visualize the effects of changing blood oxygenation on the magnetic field inside and around venous blood vessels. Signal changes associated with the response to carbogen and oxygen breathing were evaluated in different anatomic regions in healthy volunteers and in two patients with brain tumors. In the magnitude images inhalation of carbogen led to significant signal intensity changes ranging from +4.4 ± 1.9% to +9.5 ± 1.4% in gray matter and no significant changes in thalamus, putamen, and white matter. During oxygen breathing mean signal changes were smaller than during carbogen breathing. The method is capable of producing high‐resolution functional maps of BOLD response to carbogen and oxygen breathing as well as high‐resolution images of venous vasculature. Its sensitivity to changes in blood oxygenation was demonstrated by in vivo visualization of the BOLD effect via phase imaging. Magn Reson Med 54:87–95, 2005. © 2005 Wiley‐Liss, Inc.
Reduction of spinning sidebands in proton NMR of human prostate tissue with slow high‐resolution magic angle spinning
Authors: Burns Melissa A. , Taylor Jennifer L. , Wu Chin‐Lee , Zepeda Andrea G. , Bielecki Anthony , Cory David , Cheng Leo L.
Published: June 2005

High‐resolution magic angle spinning (HRMAS) NMR spectroscopy has proven useful for analyzing intact tissue and permitting correlations to be made between tissue metabolites and disease pathologies. Extending these studies to slow‐spinning methodologies helps protect tissue pathological structures from HRMAS centrifuging damage and may permit the study of larger objects. Spinning sidebands (SSBs), which are produced by slow spinning, must be suppressed to prevent the complication of metabolic spectral regions. In this study human prostate tissues, as well as gel samples of a metabolite mixture solution, were measured with continuous‐wave (CW) water presaturation on a 14.1T spectrometer, with HRMAS spinning rates of 250, 300, 350, 600, and 700 Hz, and 3.0 kHz. Editing the spectra by means of a simple minimum function (Min(A, B, …, N) for N spectra acquired at different but close spinning rates) produced SSB‐free spectra. Statistically significant linear correlations were observed for metabolite concentrations quantified from the Min(A, B, …, N)‐edited spectra generated at low spinning rates, with concentrations measured from the 3 kHz spectra, and also with quantitative pathology. These results indicate the empirical utility of this scheme for analyzing intact tissue, which also may be used as an adjunct tool in pathology for diagnosing disease. Magn Reson Med 54:34–42, 2005. © 2005 Wiley‐Liss, Inc.
In‐plane velocity encoding with coherent steady‐state imaging
Authors: Grinstead John , Sinha Shantanu
Published: June 2005

Standard phase‐contrast flow quantification (PC‐FQ) using radiofrequency (RF) spoiled steady‐state (SS) incoherent gradient‐echo sequences have a relatively low signal‐to‐noise ratio (SNR). Unspoiled SS coherent (SSC) gradient‐echo sequences have a higher intrinsic SNR and are T2/T1 weighted so that blood has a relatively large signal compared to other tissues. An SSC sequence that was modified to allow in‐plane velocity encoding is presented. Velocity encoding was achieved by inverting the readout gradients. This offers the benefit that there is no resultant increase in repetition time (TR), which avoids increased sensitivity to off‐resonance artifacts when conventional velocity‐encoding methods using separate velocity‐encoding gradients are extended to SSC sequences. The results of standard PC‐FQ and the new method from in vitro experiments of constant and sinusoidal flow, and in vivo imaging of the carotid artery were compared. Vector field maps and paths obtained from particle‐tracking calculations based on the velocity‐encoded images were used to visualize the velocity data. The technique has the potential to increase the precision of PC‐FQ measurements. Magn Reson Med 54:138–145, 2005. © 2005 Wiley‐Liss, Inc.
1H MRS‐visible lipids accumulate during apoptosis of lymphoma cells in vitro and in vivo
Authors: Schmitz Jonathan E. , Kettunen Mikko I. , Hu De‐En , Brindle Kevin M.
Published: June 2005

Proton MRS detection of cellular lipid accumulation has been suggested as a noninvasive method for detecting apoptosis or programmed cell death (PCD) in vivo. The spectral changes that have been observed in apoptotic cells include a general increase in lipid signals and a specific increase in the ratio of the lipid methylene‐to‐methyl peak intensities. These changes were investigated here following drug‐induced apoptosis, both in vitro with a murine lymphoma cell line (EL‐4) and in vivo following implantation of these cells to form subcutaneous tumors. Fluorescence microscopy and flow cytometric measurements with a lipophilic dye revealed an accumulation of cytoplasmic lipid droplets in isolated EL‐4 cells undergoing etoposide‐induced apoptosis. 1H MR spectra (both diffusion‐weighted (DW) and unweighted) showed an increase in lipid signals. However, the methylene/methyl peak ratio showed only minimal changes. Localized in vivo spectroscopy of EL‐4 tumors also showed an increase in lipid signals, including a signal from polyunsaturated lipid at 2.8 ppm, after 16–24 h of drug treatment. Again there was no significant change in the methylene/methyl peak ratio. This study confirms that MRS‐detectable lipids accumulate in tumor cells undergoing apoptosis, and therefore may be usable as a marker for the noninvasive detection of tumor cell apoptosis in the clinic. Magn Reson Med 54:43–50, 2005. © 2005 Wiley‐Liss, Inc.
Parallel imaging for NMR microscopy at 14.1 Tesla
Authors: Sutton Bradley P. , Ciobanu Luisa , Zhang Xiaozhong , Webb Andrew
Published: June 2005

Parallel imaging techniques using arrays of mutually decoupled coils have become standard on almost all clinical imaging systems. Such techniques also have great potential for high‐field magnetic resonance (MR) microscopy, where measurement times are usually long and susceptibility artifacts can be severe. However, it is technically very challenging to design efficient high‐frequency phased arrays for small‐diameter, vertical‐bore magnets, especially since standard decoupling methods, such as impedance mismatched preamplifiers, cannot be easily integrated. A four‐coil phased array was constructed for microimaging at 600 MHz, and sensitivity encoding (SENSE) and generalized autocalibrating partially parallel acquisitions (GRAPPA) reconstructions of spin‐echo and echo‐planar images of the mouse brain were performed to reduce imaging time and susceptibility artifacts, respectively. Magn Reson Med 54:9–13, 2005. © 2005 Wiley‐Liss, Inc.
Quantitative T1ρ and adiabatic Carr–Purcell T2 magnetic resonance imaging of human occipital lobe at 4 T
Authors: Gröhn Heidi I. , Michaeli Shalom , Garwood Michael , Kauppinen Risto A. , Gröhn Olli H. J.
Published: June 2005

The feasibility of performing quantitative T1ρ MRI in human brain at 4 T is shown. T1ρ values obtained from five volunteers were compared with T2 and adiabatic Carr–Purcell (CP) T2 values. Measured relaxation time constants increased in order from T2, CP‐T2, T1ρ both in white and gray matter, demonstrating differential sensitivities of these methods to dipolar interactions and/or proton exchange and diffusion in local microscopic field gradients, which are so‐called dynamic averaging (DA) processes. In occipital lobe, all relaxation time constants were found to be higher in white matter than in gray matter, demonstrating contrast denoted as an “inverse transverse relaxation contrast.” This contrast persisted despite changing the delay between refocusing pulses or changing the magnitude of the spin‐lock field strength, which suggests that it does not originate from DA, as might be induced by the presence of Fe, but rather is related to dipolar interactions in the brain tissue. Magn Reson Med 54:14–19, 2005. © 2005 Wiley‐Liss, Inc.
Miniature self‐contained intravascular magnetic resonance (IVMI) probe for clinical applications
Authors: Blank Aharon , Alexandrowicz Gil , Muchnik Lev , Tidhar Gil , Schneiderman Jacob , Virmani Renu , Golan Erez
Published: June 2005

A miniature (1.73 mm in diameter) NMR probe, which contains a magnet and a radiofrequency (RF) coil, is presented. This probe is integrated at the tip of a standard catheter and can be inserted into the human coronary arteries, creating local magnetic fields needed to obtain the NMR signal from the blood vessel walls, without the need for external magnet or RF coils. The basic theory governing the probe performance in terms of signal‐to‐noise‐ratio and contrast parameters is presented, along with measured results from test samples. The NMR signal can be analyzed to obtain tissue contrast parameters such asT1,T2and the diffusion coefficient, which may be used to detect lipid‐rich vulnerable plaques in the coronary arteries. Magn Reson Med 54:105–112, 2005. © 2005 Wiley‐Liss, Inc.
Evolution of the longitudinal magnetization for pulse sequences using a fast spin‐echo readout: Application to fluid‐attenuated inversion‐recovery and double inversion‐recovery sequences
Authors: Meara Simon J. P. , Barker Gareth J.
Published: June 2005

The fast spin‐echo (FSE) sequence is frequently used as a fast data‐readout technique in conjunction with other pulse sequence elements, such as in fluid‐attenuated inversion‐recovery (FLAIR) and double inversion‐recovery (DIR) sequences. In order to implement those pulse sequences, an understanding is required of how the longitudinal magnetization evolves during the FSE part of the sequence. This evolution has been addressed to a certain extent by previous publications, but the DIR literature in particular appears to be replete with approximations to the exact expression for the longitudinal magnetization, and several papers contain errors. Equations are therefore presented here for the evolution of the longitudinal magnetization for a FSE readout. These are then applied to calculate the magnetization available immediately prior to the 90° imaging pulse for the FLAIR‐FSE and DIR‐FSE pulse sequences. Magn Reson Med 54:241–245, 2005. © 2005 Wiley‐Liss, Inc.