bluuebunny/crossref_metadata_2025 huggingface dataset:
S100A9/S100A8: Myeloid representatives of the S100 protein family as prominent players in innate immunity
Authors: Nacken Wolfgang , Roth Johannes , Sorg Clemens , Kerkhoff Claus
Published: March 2003

Neutrophils are rapidly recruited to sites of inflammation and are thereby at the forefront of the organism's defense against numerous attacks. As unspecific phagocytes, they belong to the so‐called innate immunity. Two S100 proteins, namely S100A9 (MRP14) and S100A8 (MRP8), constitute roughly 40% of the cytosolic protein in these cells, implying by their pure abundance an important role in the effector functions of neutrophils. However, despite intense research in the past 15 years, the puzzle that may embed both molecules into the neutrophil/monocyte physiology is still incomplete. One reason might be the conformational variability the S100A9 and S100A8 molecules can adopt. They readily form hetero‐ and homodimeric, trimeric as well as tetrameric complexes, but they evidently do also exert specific functions as monomers. An ever‐increasing body of information suggests that S100A9 plays a prominent role in leukocyte trafficking and arachidonic acid metabolism. In addition, elevated levels of S100A9 and S100A8 in body fluids of inflamed tissues strengthen the view that these molecules are important players in fighting inflammation. The aim of this review is to give an update on the current developments concerning the S100A9/S100A8 molecule in biology and medicine. Microsc. Res. Tech. 60:569–580, 2003. © 2003 Wiley‐Liss, Inc.
Frog p26olf, a molecule with two S100‐like regions in a single peptide
Authors: Miwa Naofumi , Kawamura Satoru
Published: March 2003

An S100‐like calcium‐binding protein, p26olf, was originally isolated from the frog (Rana Catesbeiana) olfactory epithelium with four chromatographical steps. The primary structure of p26olf contains two S100‐like regions aligned in tandem with four functional EF‐hands. At 100 mM K+, wild‐type p26olf binds Ca2+ with a Kd value of 22 μM and a Hill coefficient of 2.0. Each EF‐hand seems to have different affinity for Ca2+: it is high in EF‐A and ‐B and low in EF‐C and ‐D. In our Ca2+‐binding model, the order of Ca2+‐binding to p26olf is EF‐B, EF‐A, EF‐C, and EF‐D. Expression of mRNA of p26olf is detected in various frog tissues: it is high in the olfactory epithelium, lung, and spleen, moderate in brain, retina, heart, and kidney, and low in liver and muscle. Immunohistochemical studies revealed that p26olf is prominently localized in the cilia of both olfactory and lung respiratory epithelium and especially enriched in the distal segment of the olfactory cilia. Several proteins in the olfactory cilia bind to p26olf in the presence of Ca2+, suggesting that they are possible target proteins of p26olf. One of these target proteins is immunologically identified as a β‐adrenergic receptor kinase‐like protein. In the olfactory cilia, p26olf may have some roles in the olfactory transduction or adaptation through interaction with this β‐adrenergic receptor kinase‐like protein. Microsc. Res. Tech. 60:593–599, 2003. © 2003 Wiley‐Liss, Inc.
Effect of hypoglycemia on brain glycogen metabolism in vivo
Authors: Choi In‐Young , Seaquist Elizabeth R. , Gruetter Rolf
Published: March 2003

The brain contains a small but significant amount of glycogen, which has long been considered to play an insignificant role in the brain. In this study, brain glycogen metabolism was measured using 13C NMR spectroscopy at 9.4 T. Brain glycogen metabolism was modulated by hyperinsulinemia resulting in a net accumulation. The role of glycogen in maintaining brain function is unknown; one possibility is that it may serve as an endogenous glucose reservoir to protect the brain against severe hypoglycemia. To address this possibility, rats were subjected to insulin‐induced moderate hypoglycemia and when the level of brain glucose approached zero, brain glycogen content began to decrease gradually, demonstrating utilization of this glucose reservoir. The brain glycogen signal never became undetectable, however, even during 2 hr of hypoglycemia. When plasma and brain glucose concentrations were restored, glycogen increased and the concentration exceeded the pre‐hypoglycemic level by several‐fold. The data suggest that brain glycogen can provide fuel for extended periods of time when glucose supply is inadequate. Furthermore, brain glycogen can rebound (super‐compensate) after a single episode of hypoglycemia. We postulate that brain glycogen serves as an energy store during hypoglycemia and that it may participate in the creation of reduced physiological responses to hypoglycemia that are involved in a symptom often observed in patients with diabetes, hypoglycemia unawareness. © 2003 Wiley‐Liss, Inc.
Miscibility and interactions in blends of two proton‐donating polymers: Poly(acrylic acid)/poly(p‐vinylphenol) blends
Authors: Li Xue‐Dong , Goh S. H.
Published: March 2003

Blends of poly(acrylic acid) (PAA) and poly(p‐vinylphenol) (PVPh) were prepared from N,N‐dimethylformamide (DMF) and ethanol solutions. The DMF‐cast blends exhibited single Tg's, as shown by modulated differential scanning calorimetry, whereas the ethanol‐cast blends had double Tg's. Fourier transform infrared spectroscopy showed that there was a specific interaction between PAA and PVPh in the DMF‐cast blends. The single‐Tg blends cast from DMF showed single‐exponential decay behavior for the proton spin–lattice relaxation in both the laboratory frame and the rotating frame, indicating that the two polymers mixed intimately on a scale of 2–3 nm. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 789–796, 2003
A review of fungal antagonists of powdery mildews and their potential as biocontrol agents
Authors: Kiss Levente
Published: March 2003

There are approximately 40 fungal species that have so far been reported as natural antagonists of powdery mildews or have been tested as their potential biocontrol agents. This review summarizes the published data on their identification, taxonomy, ecology, modes of action and biocontrol efficacy. The results obtained with the two products already registered, AQ10 Biofungicide® and Sporodex®, are also discussed.

© 2003 Society of Chemical Industry
Fusion of mitochondria in mammalian cells is dependent on the mitochondrial inner membrane potential and independent of microtubules or actin
Authors: Mattenberger Yves , James Dominic I. , Martinou Jean-Claude
Published: March 2003

Mitochondrial fusion is a poorly characterized process which has mainly been studied in yeast and Drosophila but is thought to occur in all eukaryotes. Until now, there was only indirect evidence to support such a process in mammalian cells. In this study, using a cell fusion system, we found that mitochondrial fusion occurs rapidly in mammalian cells and is completed in less than 24 h. We report that the fusion of mitochondria requires an intact mitochondrial inner membrane potential but is independent of a functional cytoskeleton.
Structure–function relationships of the extracellular domain of the autosomal dominant polycystic kidney disease‐associated protein, polycystin‐1
Authors: Weston Benjamin S. , Malhas Ashraf N. , Price Robert G.
Published: March 2003

Polycystin‐1 (PC‐1) is a member of a novel family of proteins that have a multidomain structure. Although the C‐terminal intracellular segments have been extensively studied, mainly with respect to their putative involvement in cell signalling, the potential function of the extracellular domains has received less attention. Mutations in PC‐1 result in autosomal dominant polycystic kidney disease (ADPKD) which is characterised by perturbation of transport resulting in fluid accumulation, cell proliferation and modification of the extracellular matrix. The possibility that the interaction of a component of the extracellular matrix or some external factor with PC‐1 may be important in the initiation or progression of ADPKD cannot currently be ruled out. The purpose of this review is to assess current evidence for the function of the PC‐1 extracellular domains, and their potential implications for ADPKD.
Component plane presentation integrated self‐organizing map for microarray data analysis
Authors: Xiao Li , Wang Kankan , Teng Yue , Zhang Ji
Published: March 2003

We describe a powerful approach, component plane presentation integrated self‐organizing map (SOM), for the analysis of microarray data. This approach allows the display of multi‐dimensional SOM outputs of microarray data in multiple sample specific presentations, providing distinct advantages in visual inspection of biological significances of genes clustered in each map unit with respect to each RNA sample. Beneficial potentials of the approach are highlighted by processing microarray data from yeast cells as well as human breast malignancies.
Lithium‐induced inhibition of Src tyrosine kinase in rat cerebral cortical neurons: a role in neuroprotection against N‐methyl‐D‐aspartate receptor‐mediated excitotoxicity
Authors: Hashimoto Ryota , Fujimaki Koichiro , Jeong Mi Ra , Christ Lori , Chuang De-Maw
Published: March 2003

The neuroprotective effects of lithium, a mood stabilizer, against glutamate‐induced excitotoxicity in rat cortical neurons were associated with a decrease in Tyr1472 phosphorylation of the N‐methyl‐D‐aspartate (NMDA) receptor NR2B subunit and a loss of receptor activity. Since this receptor tyrosine phosphorylation is mediated by the Src‐family tyrosine kinases, we investigated the effects of lithium on the Src kinase activity. Levels of phosphorylated Src kinase at Tyr416, an index of Src activation, were reduced after treatment with LiCl (1 mM) for more than 3 days. Protein levels of Src‐family kinases such as Src, Fyn, and Yes were unchanged by lithium treatment. The activities of cytosolic protein tyrosine kinase and protein phosphatase were also unchanged by lithium treatment, indicating the selectivity and the modulation. Moreover, the levels of postsynaptic densities (PSD) and SynGAP, the scaffolding proteins of the NMDA receptor complex, were unaltered by lithium. A Src kinase inhibitor, SU6656, and an NR2B antagonist, ifenprodil, partially blocked glutamate excitotoxicity. Our results suggest that lithium‐induced inactivation of Src kinase contributes to this drug‐induced NMDA receptor inhibition and neuroprotection against excitotoxicity.
Ribosome‐inactivating proteins depurinate poly(ADP‐ribosyl)ated poly(ADP‐ribose) polymerase and have transforming activity for 3T3 fibroblasts
Authors: Barbieri Luigi , Brigotti Maurizio , Perocco Paolo , Carnicelli Domenica , Ciani Marialibera , Mercatali Laura , Stirpe Fiorenzo
Published: March 2003

It has been known that ribosome‐inactivating proteins (RIPs) from plants damage ribosomes by removing adenine from a precise position of rRNA. Subsequently it was observed that all tested RIPs depurinate DNA, and some of them also non‐ribosomal RNAs and poly(A), hence the denomination of adenine polynucleotide glycosylases was proposed. We report now that ricin, saporin‐L2, saporin‐S6, gelonin and momordin depurinate also poly(ADP‐ribosyl)ated poly(ADP‐ribose) polymerase (auto modified enzyme), an enzyme involved in DNA repair. We observed also that all RIPs but gelonin induce transformation of fibroblasts, possibly as a consequence of damage to DNA and of the altered DNA repair system.
National Income Accounts: Measurement, Practice, and Welfare Implications of the Initial Estimates of Kosovo's GDP
Authors: Ott Mack
Published: March 2003

This article reports estimates of Kosovo's GDP for 2000 based on a survey of household expenditures, the UN's government budget, customs data, and projections of international donor organizations' assistance and investment. Estimated per capita GDP was in the range of $1135–$1185, nearly three times the $400 World Bank estimate that had been conventionally used to guide policy and technical assistance designs. The article discusses the sources of the data, provides checks from macroeconomic theory on their credibility, and prescribes statistical resources and policies to ensure a more systematic and conventional tracking of Kosovo's future aggregate economic activity.
Antileukemic Activity of Selected Natural Products in Taiwan
Authors: Chiang Lien-Chai , Chiang Win , Chang Mei-Yin , Ng Lean-Teik , Lin Chun-Ching
Published: March 2003

The aim of the present study was to evaluate the antileukemic activity of six chemical classes of pure compounds present in commonly used medicinal plants in Taiwan – such as the genus Plantago. Studies were conducted on a series of human leukemia and lymphoma cell lines. Results showed that water soluble compounds (aucubin, caffeic acid, chlorogenic acid, ferulic acid, p-coumaric acid and vanillic acid) exhibited a weak antileukemic activity (IC50: 26–56 μg/ml, SI: 2–11). On the other hand, water insoluble compounds such as triterpenoids (oleanolic acid and ursolic acid), monoterpene (linalool) and flavonoid (luteolin) possessed strong activity against human leukemia and lymphoma cell lines. Among them, linalool showed the strongest activity against histiocytic lymphoma cells U937 (IC50: 3.51 μg/ml, SI: 592.6) and Burkitt lymphoma cells P3HR1 (IC50: 4.21 μg/ml, SI: 494.1). Ursolic acid was effective against P3HR1 cells (IC50: 2.5 μg/ml, SI: 262.6) and chronic myelogenous leukemia cells K562 (IC50: 17.79 μg/ml, SI: 36.91), whereas oleanolic acid inhibited the growth of P3HR1 cells (IC50: 26.74 μg/ml, SI: 11.37). Luteolin exhibited effective activity against K562 cells (IC50: 18.96 μg/ml, SI: 5.14) and P3HR1 cells (IC50: 18.99 μg/ml, SI: 5.13). We conclude that terpenes and flavonoid in commonly used medicinal plants possess strong activity against lymphoma and leukemia cells, especially human lymphoma cells, suggesting the potential use of these compounds for treatment of lymphoma.
ASSESSING THE ECONOMIC DAMAGE FROM INDONESIAN FIRES AND THE HAZE: A CONCEPTUAL NOTE
Authors: NARAYANAN SURESH
Published: March 2003

A haze from forest fires in Indonesia affected not only that country, but also most of Malaysia, Singapore and Southern Thailand, for three months in 1997. Studies estimating the cost of the haze to the affected economies have since appeared. This note shows that "typical" empirical estimates of costs (benefits) related to the haze often contain elements of transfers between groups in an economy and can be misleading when the intention is to measure the net losses or gains to the economy as a whole.
NEW BINARY MORPHOLOGICAL OPERATIONS FOR EFFECTIVE LOW-COST BOUNDARY DETECTION
Authors: AMER AISHY
Published: March 2003

In this paper, new operational definitions of binary morphological, both conditional and nonconditional, operations are proposed. The new operations are applied to detect boundary points from binary images. Comparisons of boundary detection algorithms using proposed, standard morphological, and gradient-based operations, showing the effectiveness of the proposed operations, are given. Comparative hardware implementations of standard and proposed morphological operations are also given. Main distinguishing aspects of the new operations are: speed and low hardware implementation (i.e., e.g., low number of buffers and D-Flip–Flops).
A novel endocytic pathway induced by clustering endothelial ICAM-1 or PECAM-1
Authors: Muro Silvia , Wiewrodt Rainer , Thomas Anu , Koniaris Lauren , Albelda Steven M. , Muzykantov Vladimir R. , Koval Michael
Published: March 2003

Antibody conjugates directed against intercellular adhesion molecule(ICAM-1) or platelet-endothelial cell adhesion molecule (PECAM-1) have formed the basis for drug delivery vehicles that are specifically recognized and internalized by endothelial cells. There is increasing evidence that ICAM-1 and PECAM-1 may also play a role in cell scavenger functions and pathogen entry. To define the mechanisms that regulate ICAM-1 and PECAM-1 internalization, we examined the uptake of anti-PECAM-1 and anti-ICAM-1 conjugates by endothelial cells. We found that the conjugates must be multimeric, because monomeric anti-ICAM-1 and anti-PECAM-1 are not internalized. Newly internalized anti-ICAM-1 and anti-PECAM-1 conjugates did not colocalize with either clathrin or caveolin, and immunoconjugate internalization was not reduced by inhibitors of clathrin-mediated or caveolar endocytosis, suggesting that this is a novel endocytic pathway. Amiloride and protein kinase C (PKC) inhibitors, agents known to inhibit macropinocytosis,reduced the internalization of clustered ICAM-1 and PECAM-1. However,expression of dominant-negative dynamin-2 constructs inhibited uptake of clustered ICAM-1. Binding of anti-ICAM-1 conjugates stimulated the formation of actin stress fibers by human umbilical vein endothelial cells (HUVEC). Latrunculin, radicicol and Y27632 also inhibited internalization of clustered ICAM-1, suggesting that actin rearrangements requiring Src kinase and Rho kinase (ROCK) were required for internalization. Interestingly, these kinases are part of the signal transduction pathways that are activated when circulating leukocytes engage endothelial cell adhesion molecules, suggesting the possibility that CAM-mediated endocytosis is regulated using comparable signaling pathways.
Novel Preparation of Asymmetric Liposomes with Inner and Outer Layer of Different Materials
Authors: Xiao Zhongdang , Huang Ninping , Xu Minhua , Lu Zuhong , Wei Yu
Published: March 2003

Asymmetric liposomes whose inner and outer layer with different materials, which are very useful in liposome and membrane research, have been prepared layer by layer from reverse micelles. In general, the diameters of the liposomes ranged from 30 nm to 100 nm. Fluorescein quenching experiment showed that asymmetric liposomes with inner layer being lipid and outer single-chain [(bpy)2Ru(diazafluorenone)(CH2)15CH3](PF6)2 had been success-fully prepared. The half-life of flip-flop of bilayer is estimated for 17 days. The method present is of significance in liposome and membrane study.
Synthesis and DNA Binding Property of a Novel Peptide Nucleic Acid that Contains cis-4-Adeninyl-l-prolinol Unit
Authors: Shigeyasu Masanori , Kuwahara Masayasu , Sisido Masahiko , Ishikawa Teruhiko
Published: March 2003

A novel oxy-peptide nucleic acid that contains a cis-4-adeninyl-l-prolinol unit in the main chain (PPNA) was synthesized. The peptide nucleic acid with nine adenine units [PPNA(A9)] hybridized with the complementary DNA (T9). The hybrid showed a very sharp melting curve with Tm = 34 °C.
Preparation and Characterization of Lithium Ion Conducting Glass–Polymer Composites
Authors: Hayashi Akitoshi , Kitade Taku , Ikeda Yuko , Kohjiya Shinzo , Matsuda Atsunori , Tatsumisago Masahiro , Minami Tsutomu
Published: March 2003

Glass–polymer composite electrolytes of high lithium ion conducting oxysulfide glass and the comb-shaped poly(oxyethylene) polymer (TEC-19) were prepared. The conductivity of the composite with 2 vol% TEC-19 doped with LiClO4 was 1 × 10−3 at 100 °C and 3 × 10−5 S cm−1 at 30 °C. The composite exhibited a 4 V stable potential window versus Li+/Li.
Novel 1,2-Dilithiodisilanes Derived from Reduction of Stable Tetrakis(trialkylsilyl)disilenes with Lithium Metal
Authors: Kira Mitsuo , Iwamoto Takeaki , Yin Dongzhu , Maruyama Toyotaro , Sakurai Hideki
Published: March 2003

1,2-Dilithiotetrakis(trialkylsilyl)disilanes [(R3Si)2SiLi]2 (R3Si = t-BuMe2Si and i-Pr2MeSi) were prepared as stable off-white powder by the reduction of the corresponding tetrakis(trialkylsilyl)disilenes with lithium in THF. The 1,2-dilithiodisilanes reacted with water, iodomethane, and chlorosilanes to give the corresponding disubstituted products in high yields.
Visible Light-Induced Degradation of Methylene Blue on S-doped TiO2
Authors: Umebayashi Tsutomu , Yamaki Tetsuya , Tanaka Sigeru , Asai Keisuke
Published: March 2003

A sulfur (S)-doped titanium dioxide (TiO2) photocatalyst was synthesized by oxidative annealing of titanium disulfide (TiS2). TiS2 turned into anatase TiO2 when annealed in air. The residual S atoms occupied O-atom sites in the TiO2 to form Ti–S bonds. The S doping caused the absorption edge of TiO2 to be shifted into the lower energy region. Consequently, methylene blue adsorbed on the S-doped TiO2 was photocatalytically decomposed by visible light irradiation.
Titelbild: Large Parity‐Violation Effects in Heavy‐Metal‐Containing Chiral Compounds (Angew. Chem. 11/2003)
Authors: Schwerdtfeger Peter , Gierlich Johannes , Bollwein Tobias
Published: March 2003

Sehen heißt nicht immer wissen dies gilt beim Anblick des Lake Matheson in Neuseeland mit seinen berühmten Reflexionen des Mt. Cook und Mt. Tasman, denn oft sind die nahen Berge von ihren Spiegelbildern auf der Wasseroberfläche des Sees nicht zu unterscheiden. Auch die hochauflösende Spektroskopie kann bislang nicht zwischen Enantiomeren unterscheiden. Die relativ großen Energiedifferenzen zwischen den Enantiomeren von [(C5H5)Re(CO)(NO)I] aufgrund der Paritätsverletzung rücken nun die Detektion solch kleiner Effekte in greifbare Nähe. Einzelheiten hierzu beschreiben P. Schwerdtfeger et al. auf S. 1331 ff.
The relationship of mental illness to targeted contact behavior toward state government agencies and officials
Authors: Scalora Mario J. , Baumgartner Jerome V. , Plank Gary L.
Published: March 2003

Research in the burgeoning field of threat assessment has illuminated the importance of mental illness factors when considering risk of targeted violence—particularly related to government agencies and officials. The authors analyzed 127 cases investigated by a state law enforcement agency regarding threatening or other contacts toward public officials or state agency employees prompting security intervention. Univariate and discriminant analysis indicated that mentally ill subjects were significantly more likely to engage in more contacts as well as to make specific demands during such contacts. Mentally ill subjects were also more likely to articulate help‐seeking concerns and employ religious themes, as opposed to using insulting, degrading, or ominous language toward the target or issuing complaints regarding policy issues. Contrary to other research, the mentally ill subjects within this sample were not significantly more likely to engage in approach behavior, a threshold for higher risk of violence. Implications for threat assessment activity are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
Formation, Structure and Reactivity of Boryloxycarbyne Complexes of Group 6 Metals
Authors: Braunschweig Holger , Klinkhammer Karl W. , Koster Margot , Radacki Krzysztof
Published: March 2003

Reaction of the diborane(4) B2(NMe2)2I2 with two equivalents of K[(η5‐C5H5)M(CO)3] (M=Cr, Mo, W) yielded the dinuclear boryloxycarbyne complexes [{(η5‐C5H5)(OC)2MCO}2B2(NMe2)2] (4 a, M=Mo; b, M=W; c, M=Cr), which were fully characterised in solution by multinuclear NMR methods. The Mo and W complexes 4 a, b proved to be kinetically favoured products of this reaction and underwent quantitative rearrangement in solution to afford the complexes [{(η5‐C5H5)(OC)2MCO}B(NMe2)B(NMe2){M(CO)3(η5‐C5H5)}] (5 a, M=Mo; b, M=W); 5 a was characterised by X‐ray crystallography in the solid state. Corresponding reactions of B2(NMe2)2I2 with only one equivalent of K[(η5‐C5H5)M(CO)3] (M=Mo, W) initially afforded 1:1 mixtures of the boryloxycarbyne complexes 4 a, b and unconsumed B2(NMe2)2I2. This mixture, however, yielded finally the diborane(4)yl complexes [(η5‐C5H5)(OC)3M{B(NMe2)B(NMe2)I}] (6 a, M=Mo; b, M=W) by [(η5‐C5H5)(OC)3M] transfer and rearrangement. Density functional calculations were carried out for 4 c and 5 a, b.
Novel 4,4′‐Bipyridinium‐Based Cationic Mono‐ and Bicyclic Cyclophanes
Authors: Rajakumar Perumal , Srinivasan Kannupal
Published: March 2003

The intra‐annularly functionalised tetracationic cyclophanes 3a−b were synthesised from the corresponding m‐terphenyl dibromides and 4,4′‐bipyridine by a simple quaternisation methodology. An intra‐annularly linked tetracationic cyclophane 10 was synthesised in three steps and it possesses a concave structure and novel intramolecular CT interactions. Synthesis of the tetracationic cyclophanes 13, 16a and 16b containing carbonyl groups was accomplished from the corresponding carbonyl dibromides and 4,4′‐bipyridine. Sixfold coupling of a tricarbonyl tribromide with 4,4′‐bipyridine afforded a rare hexacationic cyclophane 18. The cyclophanes 3a and 3c form CT complexes with a bis(1H‐indol‐3‐yl)(phenyl)methane compound while the cyclophane 13 forms CT complexes with 1,4‐dimethoxybenzene and indole. Electrochemical parameters were obtained for all the cyclophanes. They exhibit two sets of redox peaks and most of them are quasireversible. The smallest‐cavity cyclophane 13 has the lowest reduction potentials in the series. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Carboxyl‐Tethered Symmetric Conjugated Polyenes as Fluorescent Transmembrane Probes of Lipid Bilayers
Authors: Quesada Ernesto , Acuña A. Ulises , Amat‐Guerri Francisco
Published: March 2003

The synthesis of a new series of fluorescent transmembrane probes in which two hydrophilic methyl ester or carboxyl groups are connected by a polymethylene chain, with four, five or six conjugated double bonds in a central position, is reported. The length of the linear structures was designed to match the width of typical lipid bilayers. These bolaamphiphilic compounds result, with overall yields higher than 80%, from an easy PdII‐catalyzed double cross‐coupling between terminal acetylene esters and conjugated 1,ψ‐dihalopolyenes, followed by selective triple bond partial reduction with activated zinc, and iodine isomerization to the all‐(E) isomer. An alternative approach, based on a Stille double cross‐coupling between the appropriate all‐(E)‐ψ‐halopolyenes and (E)‐bis(tributylstannyl)ethene, yielded mixtures that could not be resolved by standard chromatographic methods due to the presence of other simultaneous coupling reactions, which are also discussed in detail. Nevertheless, the Stille method can be of utility for the obtention of carbonyl‐polyene conjugated analogs. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Solid‐State Structural Study of the Charge‐Transfer Complexes of 5,7,9‐Trimethyl‐ and 2,11,20‐Trithia[33](1,3,5)cyclophanes
Authors: Yasutake Mikio , Araki Koji , Zhou Ming , Nogita Rika , Shinmyozu Teruo
Published: March 2003

5,7,9‐Trimethyl[33](1,3,5)cyclophane (1), with two binding sites of different donating ability, adopts aC3conformation both in the solid state (−170 °C) and in CD2Cl2solution at −90 °C. 5,7,9‐Trimethyl[33](1,3,5)cyclophane‐2,11,20‐trione (9) has the sameC3symmetry, while [33](1,3,5)cyclophane‐2,11,20‐trione (12) adopts theCsstructure in the solid state (−170 °C). The structures of1and9are the first examples of C3orC3hsymmetries in the [33](1,3,5)cyclophanes; their preferred conformers areCsboth in solution and in the solid state. The cyclophane1shows much stronger donating ability than the parent [33](1,3,5)cyclophane (2). In the TCNQ‐F4(1:1) complex of1, the donor (D) and the acceptor (A) are stacked alternately, with partial and complete D‐A overlaps being observed in the solid state (−170 °C) in the forms of partial D‐A overlap of the methyl‐substituted benzene face and TCNQ‐F4and of nearly complete D‐A overlap of the methyl‐unsubstituted benzene face and TCNQ‐F4. The former type of overlap is generally observed in the TCNQ‐F4complexes of the [3n]cyclophanes, and the transannular D‐A distance (3.22 Å) is much shorter than that in the latter (3.58 Å). This supports the idea that the methyl‐substituted benzene ring interacts more strongly than the methyl‐unsubstituted benzene ring with the acceptor. Consistently with this, two types of acceptor columns are observed, and the transannular distances between acceptors are 3.45 Å for the methyl‐unsubstituted side and 3.26 Å for the methyl‐substituted side. In the 2,11,20‐trithia[33](1,3,5)cyclophane (4)‐TCNQ‐F4(1:1) complex, an alternating D‐A stacking similar to that in [33](1,3,5)cyclophane (2)‐TCNQ‐F4(1:1) is observed. The acceptors are stacked in a parallel fashion and form an infinite column, the A−A distance in the (4)‐TCNQ‐F4(1:1) complex being 3.10 Å, and the acceptors in the unit cell are arranged parallel in a plane, the A‐A distance being 3.12 Å. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Phosphopeptide detection and sequencing by matrix‐assisted laser desorption/ionization quadrupole time‐of‐flight tandem mass spectrometry
Authors: Bennett Keiryn L. , Stensballe Allan , Podtelejnikov Alexandre V. , Moniatte Marc , Jensen Ole Nørregaard
Published: March 2003

A prototype matrix‐assisted laser desorption/ionization quadrupole time‐of‐flight (MALDI‐QqTOF) tandem mass spectrometer was used to sequence a series of phosphotyrosine‐, phosphothreonine‐ and phosphoserine‐containing peptides. The high mass resolution and mass accuracy of the instrument allowed the localization of one, three or four phosphorylated amino acid residues in phosphopeptides up to 3.1 kDa.

Tandem mass spectra of two different phosphotyrosine peptides permitted amino acid sequence determination and localization of one and three phosphorylation sites, respectively. The phosphotyrosine immonium ion at m/z 216.04 was observed in these MALDI low‐energy CID tandem mass spectra. Elimination of phosphate groups was evident from the triphosphorylated peptide but not from the monophosphorylated species. The main fragmentation pathway for the synthetic phosphothreonine‐containing peptide and for phosphoserine‐containing peptides derived from β‐casein and ovalbumin was the β‐elimination of phosphoric acid with concomitant conversion of phosphoserine to dehydroalanine and phosphothreonine to 2‐aminodehydrobutyric acid. Peptide fragment ions of the b‐ and y‐type allowed, in all cases, the localization of phosphorylation sites. Ion signals corresponding to (‐17), (‐18) and (‐17) fragment ions were also observed. The abundant neutral loss of phosphoric acid (−98 Da) is useful for femtomole level detection of phosphoserine‐peptides in crude peptide mixtures generated by gel in situ digestion of phosphoproteins. Copyright © 2001 John Wiley & Sons, Ltd.
Genetic background determines phenotypic severity of the Plp rumpshaker mutation
Authors: Al‐Saktawi K. , McLaughlin M. , Klugmann M. , Schneider A. , Barrie J.A. , McCulloch M.C. , Montague P. , Kirkham D. , Nave K.‐A. , Griffiths I.R.
Published: March 2003

The rumpshaker mutation of the proteolipid protein (Plp) gene causes dysmyelination in man and mouse. We show that the phenotype in the mouse depends critically on the genetic background in which the mutation is expressed. On the C3H background there is normal longevity whereas changing to a C57BL/6 strain results in seizures and death at around postnatal day 30. The more severe phenotype is associated with less myelin and reduced levels of major myelin proteins. There are also more apoptotic cells, including oligodendrocytes, increased numbers of proliferating cells, increased numbers of NG2+ oligodendrocyte progenitors and increased microglia compared to the milder phenotype. The number of mature oligodendrocytes is similar to wild‐type in both strains of mutant, however, suggesting that increased oligodendrocyte death is matched by increased generation from progenitors. The dichotomy of phenotype probably reflects the influence of modifying loci. The localization of these putative modifying genes and their mode of action remain to be determined. © 2003 Wiley‐Liss, Inc.
Viscoelasticity in Polymer Films on Rigid Substrates
Authors: Krupička Andreas , Johansson Mats , Hult Anders
Published: March 2003

The viscoelasticity of two thermally crosslinked polymer coatings was examined in terms of relaxation of the applied stress after a sudden strain. Two different transient methods were utilized: flat‐ended cylindrical indentation testing of a polymer film on a rigid substrate and tensile testing of a corresponding free‐standing polymer film. The correlation between tensile and indentation tests was studied. The mechanical response of a viscoelastic layer deposited on a rigid substrate was investigated as a function of indentation depth. There was good agreement between the results of the tensile and indentation tests for thick film layers at moderate indentation depths. The findings indicate that the substrate influences the coating performance by reducing the viscous contribution to the stress response and amplifying the magnitude of the equilibrium modulus for large indentation depths. The indentation method utilized here was shown to be a potentially suitable tool for the determination of Poisson's ratio of polymer films.

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Temperature‐Responsive Graft Copolymers with Poly(propylene glycol) Side Chains
Authors: Maeda Yasushi , Tsubota Miki , Ikeda Isao
Published: March 2003

The phase behavior of graft copolymers in aqueous solution was investigated. The graft copolymers consist of poly(propylene glycol) (PPG) side chains and N,N‐dimethylacrylamide (dMA), N‐vinylimidazole (VIm), and N‐isopropylacrylamide (iPA), respectively, as backbones. Phase transition temperatures of the PPG copolymers increased with increasing the content of dMA and iPA as relatively more hydrophilic comonomers and with an increase in the degree of ionization of the incorporated VIm units.

Chemical structure of the graft copolymers

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Chemical structure of the graft copolymers
Influence of Alkylaluminium Activators and Mixtures thereof on Ethylene Polymerization with a Tridentate Bis(imino)pyridinyliron Complex
Authors: Radhakrishnan Karunakaran , Cramail Henri , Deffieux Alain , François Philippe , Momtaz Ardéchir
Published: March 2003

The effect of various alkylaluminium compounds and their mixtures on ethylene polymerization catalyzed with a tridentate bis(imino)pyridinyliron catalyst is studied. Triethylaluminium and trihexylaluminium are good cocatalysts but yield polyethylenes with broad molar mass distribution (MMD) whereas triisobutylaluminium, a less efficient activator, gives polyethylenes with unimodal and narrow MMD. Specific mixtures of branched and linear alkylaluminium compounds yield highly active catalytic systems and polyethylenes with unimodal and tunable MMD.

SEC traces of PE prepared with iron catalyst and (1) TEA, (2) TiBA, and (3) THA (Al/Fe = 250) as cocatalysts.

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SEC traces of PE prepared with iron catalyst and (1) TEA, (2) TiBA, and (3) THA (Al/Fe = 250) as cocatalysts.
Thermal, morphology, and NMR characterizations on phase behavior and miscibility in blends of isotactic polystyrene with poly(cyclohexyl methacrylate)
Authors: Chang Li Ling , Woo E. M.
Published: March 2003

The miscibility and phase behavior in a binary blend of isotactic polystyrene (iPS) and poly(cyclohexyl methacrylate) (PCHMA) were investigated by differential scanning calorimetry, optical microscopy (OM), and solid‐state 13C cross‐polarity/magic‐angle spinning NMR. The iPS/PCHMA blend was miscible when all compositions showed a single composition‐dependent glass‐transition temperature (Tg) and when the blend went through a thermodynamic phase transition upon heating to above the lower critical solution temperature as determined by OM measurements. The 1H NMR spin‐relaxation times in the laboratory frame (T) and in the rotating frame (T) for iPS/PCHMA blends with various compositions and neat components were directly measured through solid‐state13C NMR. The results of T indicated that the blends are homogeneous, at least on a scale of 75–85 nm, confirming the miscibility of the system. The single decay and composition‐dependent T values for each blend further demonstrated the blends are homogeneous on a scale of 2.5–3.5 nm. The results suggested that iPS and PCHMA are intimately mixed at the molecular level within the blends at all compositions. The tacticity of polystyrene does not seem to adversely influence the miscibility in blends of iPS/PCHMA. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 772–784, 2003