Gellan gum, a microbial polysaccharide, consisting of tetra-saccharide unit, glucose, glucuronic acid, glucose and rhamnose, forms a transparent gel which is heat-resistant in the presence of divalent cations. Since 1989, the collaborative research group was organised in the Research Group of Polymer Gels affiliated to the Society of Polymer Science, Japan, consisting of various laboratories with different disciplines to clarify the mechanism using the common purified sample. This special issue contains 19 papers on the molecular conformation, gel-sol transition, interaction of gellan and water, cations and sugar, based on rheology, NMR, ESR, DSC, light scattering, osmotic pressure, small angle x-ray scattering, dielectric measurement, atomic force microscopy and the industrial application of gellan gum presented at the 4th International Conference on Hydrocolloids - OCUIS '98 by the collaborative group members and by international experts.

Over the past 40 years, Rotational Isomeric State (RIS) models for hundreds of polymer structures have been developed. The RIS approach is now available in several software packages. The user is often faced with the time-consuming task of finding appropriate RIS parameters from the literature. This book aims at easing this step by providing a comprehensive overview of the models available. It reviews the literature from the first applications of RIS models to the end of 1994, comprises synthetic as well as naturally orccuring macromolecules, and tabulates all the pertinent features of published models. It will help readers, even when not very familiar with the method, to take advantage of this computationally efficient way of assessing the conformational properties of macromolecular systems.

A. Grosberg, S. Nechaev Polymer Topology H.-W. Kammer, J. Kressler, C. Kummerloewe Phase Behavior of Polymer Blends - Effects of Thermodynamics and Rheology B. Hammouda Sans from Homogeneous Polymer Mixtures: A Unified Overview E.T. Kang, K.G. Neoh, K.L. Tan X-Ray Photoelectron Spectroscopic Studies of Electroactive Polymers

Soft matter and biological systems pose many challenges for theoretical, experimental and computational research. From the computational point of view, these many-body systems cover variations in relevant time and length scales over many orders of magnitude. Indeed, the macroscopic properties of materials and complex fluids are ultimately to be deduced from the dynamics of the microsopic, molecular level. In these lectures, internationally renowned experts offer a tutorial presentation of novel approaches for bridging these space and time scales in realistic simulations. This volume addresses graduate students and nonspecialist researchers from related areas seeking a high-level but accessible introduction to the state of the art in soft matter simulations.

Thepolymerizationofole nsanddi-ole nsisoneofthemostimportanttargets inpolymerscience.Thisreviewarticledescribesrecentprogressinthis eldand deals with organo-transition metal complexes as polymerization catalysts. - cent developments in organometallic chemistry have prompted us to nd a precise description of the mechanism of propagation, chain transfer, and terminationstepsinthehomogeneouslymetal-assistedpolymerizationofole ns anddiole ns.Thus,thisdevelopmentprovidesanideafordesigninganycatalyst systems that are of interest in industry. Recently,the agostic interactionofalkylgroup(s)ontransitionmetalshas emerged as highly basic and new concept and is found to be important in understandingthemechanismofthemetal-catalyzedhomogeneousoligomer- ation and polymerization of a-ole ns. Early transition metal alkyl complexes generallyhavepartiallyionicM-C bondsandshowa-agostichydrogeninter- tion that somewhat stabilizes the catalytically active species by providing el- tronsatavacantsite onthe metal.Thisisinsharp contrasttothefactthatlate transition metal alkyl complexes show mainly b-agostic hydrogen interaction that causes the hydrogen transfer easily through b-hydrogen elimination and reductive elimination, and that gives rise to the oligomerization of ole ns. Organometalliccomplexesoftheearlyandlatetransitionmetalshavebeenused as catalysts for ole n oligomerization and polymerization. The mechanism involved in these catalyst systems depends very much upon the kind of metal centersaswellastheirco-ligands,andthusthedi?erentmechanismswhichcan bedistinguishedbydetailedinvestigationsshouldbeassumedforearlyandlate transition metal catalysts. In this contribution, we review the mechanism of polymerization and oligomerization involving early transition metals, taking as our basis recent resultsinadvancedorganometallicchemistry.Firstofall,somerecentexamples of the previous reviews concerning the Ziegler-Natta polymerization are cited [1-10]. Then, relevant new reports are surveyed in a systematic fashion.

The liquid crystalline state may be identified as a distinct and unique state of matter which is characterised by properties which resembles those of both solids and liquids. It was first recognised in the middle of the last century through the study of nerve myelin and derivatives of cholesterol. The research in the area really gathered momentum, however, when as a result of the pioneering work of Gray in the early 1970's organic compounds showing liquid crystalline properties were shown to be suitable to form the basis of display devices in the electronic products. The study of liquid crystals is truly multidisciplinary and has attached the attention of physicists, biologists, chemists, mathematicians and electronics engineers. It is therefore impossible to cover all these aspects fully in two small volumes and therefore it was decided in view of the overall title of the series to concentrate on the structural and bonding aspects of the subject. The Chapters presented in these two volumes have been organised to cover the following fundamental aspects of the subject. The calculation of the structures of liquid crystals, an account of their dynamical properties and a discussion of computer simulations of liquid crystalline phases formed by Gay Berne mesogens. The relationships between molecular conformation and packing are analysed in some detail. The crystal structures of liquid crystal mesogens and the importance of their X ray scattering properties for characterisational purposes are discussed.

The Fifth Chinese Peptide Symposium, hosted by Lanzhou University, was held at Lanzhou, China July 14-17, 1998, with 156 participants, including 30 scientists from abroad, representing nine countries. The four-day conference was both intense and spiritually rewarding. Our goal for CPS-98 was to provide a forum for the exchange of knowledge, cooperation and friendship between the international and Chinese scientific communities, and we believe this goal was met. The symposium consisted of 8 sessions with 42 oral and 90 poster presentations, including synthetic methods, molecular diversity and peptide libraries, structure and conformation of peptides and proteins, bioactive peptides, peptide immunology, De Novo design and synthesis of proteins and peptides, ligand-receptor interactions, the chemistry-biology-interface and challenging problems in peptides. The enthusiastic cooperation and excellent contributions were gratifying and the active response of the invited speakers contributed to the success of the symposium. The presentations were of excellent caliber and represented the most current and significant aspects of peptide science. Dr. Kit Lam of the University of Arizona and Dr. Yun-Hua Ye of Peking University were the recipients of "The Cathay Award" sponsored by the H. H. Liu Education Foundation, offered for their seminal contribution in peptide science and the Chinese Peptide Symposium. Four outstanding young scientists were selected by the organizing committee to receive awards sponsored by Haikou Nanhai Pharmaceutical Industry Co. Ltd. (Zhong He Group).

Holographic Interferometry provides a valuable and up-to-date source of information in the rapidly expanding field. The eight specialists` contributions cover the principles and methods currently in use. The scope of the book has been limited to the study of opaque object and ample space has been devoted to a comprehensive treatment of the phenomena of fringe formation, with a particular emphasis on the quantitative evaluation of the holographic interference fringe patterns. The emergence of computer-aided fringe analysis and phase-shifting techniques have simplified considerably the quantative real-time measurements of object shapes and deformations. The last two chapters provide a reasonably detailedoverview of full-field holographic methods for the measurement of shapes, displacements, dervatives, difference displacements and vibrations.

Pt. A: NMR and other Spectroscopic Methods. Pt. B: Mechanical Methods