bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodesulphurization of mengen lignite by Rhodoccocus rhodochrous in a batch stirred and aerated tank fermenter
Authors: Bayram Z. , Bozdemir T. , Durusoy T. , Yürüm Y.
Published: December 2004

The biodesulphurization of Mengen lignite by a mesophilic bacterium, Rhodococcus rhodochrus ATCC 53968, was investigated in a batch stirred and aerated reactor. The experiments were carried out at 28°C with an inoculum percentage, initial pH, initial sodium acetate and lignite concentration of the biodesulphurization medium of 8% [v/v], 6.5 mM, 20 mM and 20 g/l, respectively. Variations in the sulphur contents of the lignite relative to the biodesulphurization period were monitored. The effects of the stirring and aeration rates on the removal of different sulphur forms from coal were investigated in the ranges 450–1,200 rpm and 0.1–0.53 vvm and the optimum values were found to be 500 rpm and 0.18 vvm, respectively. An increase in the total sulphur reduction with increasing biodesulphurization time was observed. The maximum total sulphur removal percentage was found to be 15.2% at 1,200 rpm after four days of incubation. The highest total sulphur removal rate was calculated on the second day of microbial desulphurization for each run. The total and organic sulphur contents of the coal after biodesulphurization were correlated with the stirring and aeration rates by using the non‐linear least squares regression method. In the experimental runs lasting 8 days, the highest organic sulphur reducing percentage of 10.1% was obtained at a stirring rate of 500 rpm and an aeration rate of 0.40 vvm.
Production of extracellular polysaccharides by a Rhizobium species from the root nodules of Melilotus alba
Authors: Datta C. , Basu P. S.
Published: December 2004

The Rhizobium sp., isolated from the root nodules of the leguminous fodder herb Melilotus alba, produced large amounts of extracellular polysaccharides (EPS) (963.5 μg/ml) in a yeast extract mannitol medium. Growth and EPS production started simultaneously, but EPS production reached its maximum during the stationary phase of growth of the bacteria, at 20 hours. EPS production was increased with all of the thirteen sugars tested. Different nitrogen sources, such as nitrates, glutamic acid, casamino acid and L‐asparagine, increased the EPS production although it was inhibited by glycine, nitrite and ammonium salts. Among the vitamins and metal ions, only pyridoxal phosphate and ZnSO4 promoted EPS production. Attempts were made to optimize the cultural requirements for growth and maximum EPS production. Maximum EPS production (1457.0 μg/ml) was obtained when the medium was supplemented with glucose (1%), pyridoxal phosphate (2 μ g/ml), ZnSO4 × 7 H2O (10 μg/ml) and glutamic acid (0.1%). Under these conditions, the production was increased by 254.3% compared to the control. The EPS contained arabinose, xylose and rhamnose monomers. The presence of arabinose and xylose in the EPS produced by a Rhizobium sp. was uncommon.
Dynamic responses of biofilters to changes in the operating conditions in the process of removing toluene and xylene from air
Authors: Marek J. , Paca J. , Gerrard A. M.
Published: December 2004

The dynamic behaviour of biofilters intended to remove toluene and xylene from air was studied during transient states. Laboratory scale biofilters were filled with a mixture of peat, bark and wood and inoculated with a mixed microbial population. Toluene and xylene were applied both as single pollutants and as mixtures. Attention was focused on the evaluation of the following transients: the response of biofilters to step changes and peaks in pollutant concentrations, the effect of changes between single and multiple pollutant loadings and the response to shutdown periods.

The biofilters demonstrated a good dynamic stability during transient states induced by change in inlet pollutant concentrations. Their time periods did not exceed three hours. No interaction between xylene and toluene degradation was observed during changes in loading with single pollutants or their mixture. The performance interruptions lasting less than 24 hours were found to have no significant influence on the removal efficiency of biofilters. When the biofilters were reacclimated after longer starvation periods, a short temporary decrease in efficiency whose minimum and duration were proportional to the length of a preceding shutdown period was observed. The longest starvation period (7 days) resulted in a reacclimation lasting 7 hours only. Adaptations of a microbial population to new operating conditions as well as sorption/desorption processes were suggested as the main factors influencing the dynamic reponse characteristics.
Improvement of the bioavailability of hydrocarbons by applying nonionic surfactants during the microbial remediation of a sandy soil
Authors: Löser C. , Seidel H. , Zehnsdorf A. , Hoffmann P.
Published: December 2004

During the microbial treatment of a sandy model soil artificially contaminated with polycyclic aromatic hydrocarbons (PAHs), a large residual pollution was found. The remainig PAHs were sorbed into the micropores of the soil and were therefore not bioavailable. Using a lab‐scale precolator, the microbially pretreated soil was subjected to aftertreatment with surfactants with the aim of further degradation of its pollution. Two commercial nonionic surfatants of the polyethoxylate type, Präwozell F1214/5 N and Sapogenat T‐300, were used. The surfactants differ both in their physicochemical properties (CMC value, PAH solubilization capacity, adsorption onto soil) and in their microbial degradability. During aftertreatment under permanently aerobic conditions, only a weak PAH accumulation in the liquid phase was observed, which was due to a low solubilization rate as well as to simultaneous microbial degradation of the dissolved PAHs. Temporary anaerobiosis successfully suppressed the microbial degradation of both the surfactant and the solubilized PAHs, resulting in a more intensive PAH accumulation. But the PAH content of the soil ‐ the essential criterion for evaluating the efficiency of surfactant application ‐ was not decreased to a larger extent with surfactants than without them. To find out why the surfactants failed to act, the surfactant and hydrocarbon distribution among the liquid and solid phases was studied in mixtures of phenantherne‐spiked solis and Präwozell‐containig liquids; at heavy phenanthrene loading, the aqueous phase was saturated with PAH; at weak loading, it was unsaturated. Model‐aided data analysis showed that the soil may contain PAH in two fractions: strongly sorbed into soil pores and, in the case of heavy loading, also weakly attached to the soil surface. The latter is easily extractable, resulting in a PAH‐saturated liquid, while strongly adsorbed PAH is only partially dissolved due to competition between the micelles and the soil pores for the PAH. The microbially pretreated soil contains only strongly bound PAHs, which are as difficult to extract by surfactants as they are poorly accessible for microbes.
Influence of crude oil contamination on the bacterial community of semiarid soils of Patagonia (Argentina)
Authors: Pucci O. H. , Bak M. A. , Peressutti S. R. , Klein I. , Härtig C. , Alvarez H. M. , Wünsche L.
Published: December 2004

Autochthonous bacteriocenoses in semiarid soils in Patagonia were found to be capable of rapidly adapting to high contamination with crude oil. This adaptation at community level is due to the selective enrichment of hydrocarbon‐utilizing bacteria always present in these soils. Immediately after a heavy contamination with crude oil, the authochthonous bacteriocenosis contained about 28% hydrocarbon‐utilizing bacteria which could be classified into eight ecotypes with characteristic metabolic profiles. Mainly n‐alkanes were used as growth substrates of representative strains. After seven months' exposure to crude oil, the bacteriocenosis consisted almost entirely of hydrocarbon‐utilizing bacteria. At least fourteen ecotypes were distinguishable, and the majority of representative strains were able to metabolize a broad spectrum of aliphatic and aromatic hydrocarbons. Corresponding to the significant alteration of the physiological diversity, drastic changes to the taxonomic diversity were also found. Whereas at the beginning of the study the autochthonous bacteriocenoses were dominated by GRAM‐positive genera of the Actinomycetales (Dietzia, Gordona, Nocardia, Rhodococcus, Streptomyces) with high ecological potency, after just two months' exposure to crude oil, GRAM‐ negative bacteria (especially Pseudomonas stutzeri) became predominant within the hydrocarbon‐utilizing bacteriocenoses accompanied by some GRAM‐positive genera of the Actinomycetales with a significantly lower abundance. These findings underline the importance of Pseudomonas and some genera of Actinomycetales for processes of natural attenuation and the technically supported in situ bioremediation of soil polluted by crude oil in Patagonia.
Variation revealed by RAPD‐PCR profiles of microsymbiont Anabaena azollae strains from four N2 fixing Azolla cultures
Authors: Subhashini R. , Kumar K. , Kannaiyan S.
Published: December 2004

Nitrogen fixing Anabaena azollae strains isolated from four different Azolla cultures were characterized based on their total protein profile and RAPD profile to study the existing variation among them. As expected, the isolates showed almost similar protein banding patterns, but exhibited differences in 40–70 KDa protein subunits. Polymerase chain reaction of the DNA of the isolates, using four different primers, amplified specific sequences of DNA and showed clear polymorphism among the isolates. The RAPD profile generated the fingerprinting pattern characteristic of each strain based on the sequence of the primers used. Common band sharing observed between the strains A. azollae‐RS‐KK‐SK‐AM and A. azollae‐RS‐KK‐SK‐RP probably represents maternal inheritance of DNA to the progeny. The polymorphic bands were generated specifically for the isolates A. azollae‐RS‐KK‐SK‐RP and A. azollae‐RS‐KK‐SK‐AM with primers numbered 2 and 4, respectively, which could be developed as possible markers for these isolates.
Development of transgenic rice pure lines by particle bombardment‐mediated transformation and genetic analysis‐based selection
Authors: Tang K. , Wu A. , Yao J. , Qi H. , Lu X.
Published: December 2004

Mature seed‐derived callus from an elite Chinese japonica rice cv. Eyl 105 was transformed with a plasmid containing the selectable marker hygromycin phosphotransferase (hpt) and the reporter β‐glucuronidase (gusA) genes via particle bombardment. After two rounds of selection on hygromycin (30 mg/l)‐containing medium, resistant callus was transferred to hygromycin (30 mg/l)‐containing regeneration medium for plant regeneration. Twenty‐three independent transgenic rice plants were regenerated from 127 bombarded callus with a transformation frequency of 18.1%. All the transgenic plants contained both gusA and hpt genes, revealed by PCR/Southern blot analysis. GUS assay revealed 18 out of 23 plants (78.3%) proliferated on hygromycin‐containing medium had GUS expression at various levels. Genetic analysis confirmed Mendelian segregation of transgenes in progeny. From R2 generations with their R1 parent plants showing 3:1 Mendelian segregation, we identified three independent homozygous transgenic rice lines. The homozygous lines were phenotypically normal and fertile compared to the control plants. We demonstrate that homozygous transgenic rice lines can be obtained via particle bombardment‐mediated transformation and through genetic analysis‐based selection.
Formation of aminium lactates in lactic acid fermentation. Fermentative production of 1,4‐piperazinium‐(L,L)‐dilactate and its use as a starting material for the synthesis of dilactide (Part 2)
Authors: Kamm B. , Kamm M. , Richter K. , Reimann W. , Siebert A.
Published: December 2004

A fermentation process for manufacturing 1,4‐piperazinium‐(L,L)‐dilactate from renewable raw materials and a method for processing this product into L,L‐dilactide are described. Lactic acid fermentation with Lactobacillus paracasei was modified in such a way that pH control occurred by using an aqueous solution of piperazine as a correcting agent instead of sodium hydroxide solution. The production of a stoichiometrically composed piperazinium lactate was possible when the pH was 5.0. From 5.0 kg of glucose and 2.15 kg of piperazine, 6.65 kg of 1,4‐piperazinium‐(L,L)‐dilactate were formed in the fermentation process. Separation from fermentation broth, purification and concentration of the product in aqueous solutions were carried out by means of ultrafiltration, nanofiltration and electrodialysis. Total product retention by the membranes used was about 33%. The crystalline salt was obtained by vacuum evaporation. Processing of the 1,4‐piperazinium‐(L,L)‐dilactate into L,L‐dilactide was performed in a special glass reactor. A product yield of 70% was achieved. The purified product was characterized by elementary analysis, as well as solubility behaviour, polarity and spectroscopic data. An overall process consisting of the stages fermentation, purification and concentration of piperazinium dilactate as well as cyclization of the latter to dilactide is described.
Investigation into the biotechnological modification of wood and its application in the wood‐based material industry
Authors: Unbehaun H. , Dittler B. , Kühne G. , Wagenführ A.
Published: December 2004

Because of the growing utilization of renewable raw materials, the technical use of lignocellulosic fibres from wood and other annual plant materials is becoming increasingly important. The conventional production process of fibreboards is characterized by high‐energy consumption and use of ecologically insecure synthetic lesins. Approximately 40 to 45% of the total energy expenditure are used for the thermo‐mechanical pulping. Because of high plastication temperatures, an inactive lignin crust on the fibre surface is formed. For that reason, for glueing of the fibres, urea formaldehyde and melamin resins are usually used. The costs for the resin amount to approximately 50% of the entire material costs. In addition, environmental problems are caused. The aim of our investigation is the reduction of energy and resin consumption by enzymatic modification of wood chips and the enzymatic activation of the inherent bonding strength of the material. The first industrial use of fungi for the modification of wood was in the production of “Myco wood”. Pleurothus ostreatus and Trametes versicolor were applied for nonsterile delignification of beech wood. The present investigation of the authors deals with the mycological pre‐treatment of wood chips in order to reduce the energy consumption during wood pulping. The screening results favour the brown rotter Gleophyllum trabeum for pinewood (Pinus silvestris) and the white rotter Trametes hirsuta for beech (Fagus silvatica). Both species show resistance against mould fungi. The use of submerged inoculum of these fungi has the advantage over wheat inoculum that the lag phase is less than 12 hours and that the addition of nutrients or fungicides is not necessary. Short‐time wood chip incubation results in a 40% decrease of energy consumption during thermo‐mechanical pulping and in improved fibreboard properties. Lignin reduction could not be determined by gravimetrical and x‐ray microanalysis.

Comparative investigations of fibre incubation using laccase, a submerged culture of Trametes versicolor and rape straw fibres show a high increase in bending and tensile strength and an improvement in the hygroscopic properties of glue‐free fibre boards for the last two incubation kinds. Similar effects have been obtained incubating pine wood fibres for the production of fibre sheets with enzyme medium of Trichoderma reseei.
Functionalized Conducting Polymers—Towards Intelligent Materials
Authors: Garnier Francis
Published: December 2004

Organic conjugated polymers and oligomers constitute a three‐dimensional network of molecular wires, in which all monomeric units can be functionalized with various prosthetic groups. By varying the nature of these groups, specific interactions with external physical or chemical phenomena can be developed in these materials, leading to molecular devices such as sensors, transducers, memories and logic operators. Chemists have already mastered the realization of many of these functional elements, which mimic those existing in organized beings. The further assembly of these elements in multifunctionalized organic conducting polymers and oligomers will represent the next step towards intelligent materials.
X‐ray techniques using synchrotron radiation in materials analysis
Authors: Lengeler Bruno
Published: December 2004

The extraordinary properties of SR have opened up new horizons for all techniques which use vacuum ultraviolet light and X‐rays. In this article, some applications of SR in materials science have been discussed. X‐ray absorption spectroscopy is a local, atom specific probe of the geometrical and electronic structure of the absorbing species. As an example, the lattice site location and the valence of Co in a doped high‐Tc, superconductor YBa2Cu2–5Co0–5O7–4 has been discussed.
Liquid crystals consisting of simple polyene schiff bases
Authors: Malthête Jacques
Published: December 2004

Schiff bases which have LC‐phases and could act as models for conjugated polyenes involved in the process of vision have recently been reported by Wann and Harbison of the State University of New York. The relationship of these new materials to other liquid crystalline compounds is explained.
Eurogel 1989 in colmar
Authors: Roggendorf Hans
Published: December 2004

Lothar Kador reports in detail on his visit to an international symposium on optical memory in the East, and Hans Roggendorf describes proceedings at the Eurogel meeting held recently in France.
Advanced materials for reversible optical storage
Authors: Engler Edward M.
Published: December 2004

The development of semiconductor lasersand the application of materials such as garnets as the recording media have led to fast progress in optical storage technology. The ability of the new methods (for mode of information storage see figure) to compete with magnetic storage are discussed, new materials are assessed, and techniques such as direct overwrite through field or laser modulation are described.

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Silica surface sensitization and chemical sensors
Authors: Clechet Paul , Jaffrezic‐Renault Nicole
Published: December 2004

The surface modification of materials and its control now appear to be a challenge in many fields of technology, for example, composites, chromatography, and chemical sensors.

A well controlled engineering process for producing self‐assembled long chain monolayers on a thin thermal silica layer has been perfected in our laboratory. The monolayers are covalently bonded to SiO2/Si(100) heterostructures and have been chemically (chemical analysis, pH sensitivity) and physically (spectroellipsometric and capacitance measurements) characterized.

The application of this process for sensitizing the surface of the silica insulator used in CHEMFET chemical sensors is presented using the example of an Ag® sensitive device. The main features of this sensor are its short response time(< 2 s) and its long lifetime (> 3 months).
The development of electrically Conducting Polymers
Authors: Naarmann Herbert
Published: December 2004

The development of polyacetylenes, polythiophenes and polypyrroles, amongst other conducting polymers is traced from an industrial point of view by one of the pioneers in the field. The methods used for the production of the materials are described and present and future applications are assessed.
Intercalation chemistry of conducting polymers: New crystalline microlaminate phases in the polyaniline/feocl system
Authors: Kanatzidis Mercouri G. , Wu Chun‐Guey , Marcy Henry O. , DeGroot Donald C. , Kannewurf Carl R. , Kostikas Athanasios , Papaefthymiou Vasilios
Published: December 2004

Molecular nano‐composites of two electrically active but chemically deverse components, organic conducting polymers and inorganic metaloxide bronzes, can be formed by the in situ intercalative oxidative polymerization of aniline in FeOCl. Two forms of the normally amorphous polyaniline, in a cryustalline, well‐defined environment have been discovered, one semiconducting and one metallic. These hybrid materials are also suitable for the study of oriented conducting polymers.
Triphenyl methane dyes as sensor materials for solvent detection with surface‐acoustic‐wave devices
Authors: Dickert Franz L. , Bertlein Gerhard , Mages Gert , Bulst Wolf‐E.
Published: December 2004

Highly‐colored phthalide carbenium ions (see figure) embedded in a matrix of phenols can form the basis of solventsensing devices able to detect a variety of solvents in concentrations down to a few ppm. Solvent absorption disturbs hydrogen bonding producing a less favorable environment for the cations, the changing concentration of which can be monitored using optical absorption, or SAW‐devices.

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High‐Tc Superconductors
Authors: Bogner Günther , Hoenig Hans E.
Published: December 2004

Applications‐oriented R & D in ceramic high‐Tc superconductors is pursued at Siemens in close cooperation with workers at Hoechst (amongst others). Recent success, e.g. with a coplanar stripline resonator for 6.52 GHz, and high‐quality thin‐films, are described and production and processing methods are reviewed.
Solid‐state 13C‐NMR on oriented films of liquid‐crystalline polymers
Authors: Wiesner Ulrich , Schmidt‐Rohr Klaus , Boeffel Christine , Pawelzik Ute , Spiess Hans Wolfgang
Published: December 2004

Optically transparent films of a liquid crystalline (LC) polymer with azobenzene mesogens, which has recently been exploited for reversible holographic information storage, have been studied using solid‐state NMR. The extent to which optically switching the dye with laser light affects the alignment of the LC matrix, a factor which could influence the performance of the materials in storage applications, is examined.
Computing the structure of pillared Clays
Authors: Gale Julian D. , Cheetham Anthony K. , Jackson Robert A. , Callow C. Richard A. , Thomas John M.
Published: December 2004

The behavior of an organic cation in a pillared clay has been successfully simulated taking into account both long‐range electrostatic interact‐ions and short‐range interactions between cation guests and host lattice. Anilinium cation pillars in vermiculite (a high charge density smectite) is the system studied and the simulations (e.g. see figure) compare favorably with the experimental 3D crystal structure.

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Ferroelectric liquid crystalline polysiloxanes with high spontaneous polarization and possible applications in nonlinear optics
Authors: Kapitza Heinrich , Zentel Rudolf , Twieg Robert J. , Nguyen Cattien , Vallerien Sven Uwe , Kremer Friedrich , Willson C. Grant
Published: December 2004

Ferroelectric liquid crystalline (LC) polymers (see figure), which in the smectic C* phase exhibit the highest yet known spontaneous polarization for LC polymers of up to 430 nC/cm2, a value which approaches that of the best low molecular weight materials, have been synthesized, based on chiral polysiloxanes. A copolymer is also reported which shows promise for second harmonic generation (frequency doubling) of the 1064 nm Nd:YAG fundamental (to 532 nm) without poling in an external field.

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An all‐organic "soft" thin film transistor with very high carrier mobility
Authors: Garnier Francis , Horowitz Gilles , Peng Xuezhou , Fichou Denis
Published: December 2004

The first all‐organic electronic device to boast the same characteristics as silicon‐based ones is reported. Not only does the use of an organic insulating layer result in an increased charge‐carrier mobility in the semiconductor, but it also imparts a flexible quality to the whole device which allows it to be rolled up, bent or twisted without reducing performance. The organic‐based devices also show remarkable tolerance towards moisture and impurities, production being possible in the normal laboratory environment.
Charge transport in polyethylene–graphite composite materials
Authors: Ezquerra Tiberio A. , Kulescza Mareck , Cruz Carlos Santa , Baltá‐Calleja Francisco J.
Published: December 2004

Deviation from the predictions of percolation theory for conduction in polythylene‐graphite composites (see figure) have been explained in tems of tunneling between the conducting graphite particles in the insulating polymer matrix, a mechanism which is believed to be prevalent at lower graphite concentration.

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Molecular Materials II Part C. Molecular electronics?
Authors: Miller Joel S.
Published: December 2004

In the final part of this article, the potential contributions of magnetic and superconducting components to the goal of molecular electroncis are analyzed, as are alternative scenarios involving optically based computing, neural networks and cellular automata. An assessment of future targets is given.
The phase equilibrium diagram of Bi2O3–SrO–CaO–CuO–A tool of processing the high‐ Tc superconducting bismuth‐compounds
Authors: Majewski Peter , Hettich Bernhard , Jaeger Herbert , Schulze Klaus
Published: December 2004

Research News: The preparation of single phase ceramics and the processing of complex compositions is greatly simplified by a comprehensive understanding of the phase equilibria. Exploiting this knowledge has enabled researchers to prepare the 2223 phase of the superconductor Bi2Sr2Can−1CunO2n+4+d in 80% purity. The information which can be gleaned from a phase diagram of a superconducting system is explained and the use of the data in producing materials suited for use in superconducting components is described.
Liquid crystal polymers containing macroheterocyclic ligands 6. synthesis of mesomorphic polymers containing crown ethers by cationic cyclopolymerization and cyclocopolymerization of 1,2‐bis(2‐ethenyloxyethoxy)benzene derivatives containing mesogenic side groups
Authors: Rodenhouse Randall , Percec Virgil
Published: December 2004

Communication: Side‐chain LCPs containing both a crown ether and a mesogenic group in each structural unit of the polymer are reported based on the monomer shown in the figure. Liquid crystals containing macroheterocyclic ligands are of interest since they provide a novel approach to self‐assembled systems which combine selective recognition with external regulation.

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Superconducting organic thin films prepared using an evaporation technique
Authors: Kawabata Kazushige , Tanaka Keiji , Mizutani Makoto
Published: December 2004

Research News: Superconducting organic thin films have been produced for the first time making use only of dry processes. The vacuum‐evaporation method is suitable for the production of thin films of BEDT‐TTF iodide either from electrochemically produced BEDT‐TTF iodide or directly from BEDT‐TTF and iodine. The insulating films formed in the deposition process are converted to the conducting form by annealing and analyzed using X‐ray diffraction (see Figure). The ‘dry’ nature of the process is advantageous as solvents can damage the fine crystals formed and make the production of homogeneous thin films difficult.

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Defects in Continuous Media
Authors: Weber Andreas , Bodenschatz Eberhard , Kramer Lorenz
Published: December 2004

Review: Defects often determien the mechanical and other properties of materials to a large extent. An understanding of these ordering imperfections would therefore facilitate the design of improved materials. Using nematic liquid crystals as an example, the various theoretical approaches to the description of defects are described and a correlation with the information obtaiend through experiment allows the success of the methods to be assessed.
Controlled synthesis of inorganic materials using supramolecular assemblies
Authors: Mann Stephen , Meldrum Fiona C.
Published: December 2004

Research News: Protein cages acting as constrained reaction environments have recently been used to synthesize inorganic materials of nanometer dimensions. The size of the cavity within the protein and the level of loading with metal ions determine the final dimensions of the materials, and therefore site‐specific modification of the inner surface of the protein could fine‐tune the supramolecular assembly for tailored inorganic materials synthesis. Some of the latest developments are discussed.
Dye‐doped polymer films: From supramolecular photochemistry to the molecular computer
Authors: Wild Urs P. , Rebane Alexander , Renn Alois
Published: December 2004

Research News: Hole burning in the spectra of dye‐doped polymer films provides the opportunity for high density data storage, holographic image storage and even five‐dimensional image storage is feasible (three spatial dimensions, frequency, and electric field). The background of the technique and recent progress in the optical data storage with lasers where impressive resolution and grey scales have been achieved (see Figure) is discussed.

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Template synthesis of polymeric and metal microtubules
Authors: Martin Charles R.
Published: December 2004

Research News: The pores in a microporous membrane can act as templates for the synthesis of polymeric and metallic microtubules. The tubules thus produced (see Figure) have monodispersed diameters and lengths and potential applications ranging from drug‐delivery systems to microwave components and in electronic and opto‐electronic devices.

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Preparation of unleaded Bi2Sr2Ca2Cu3O10
Authors: Majewsky Peter , Hettich Bernhard , Schulze Klaus , Petzow Günter
Published: December 2004

Communication: The 2223 single‐phase region in the Bi2O3–SrO‐CaO‐CuO system has been defined, enabling the preparation of pure (> 90%), unleaded Bi2Sr2Ca2Cu3O10. The bismuth content of the superconductor, which is better suited for research than the leaded variety, is found to be significantly higher (at 2.5) than expected from the exact stoichiometry. The preparation conditions and the phase diagram are discussed.
Absorption spectra of charged oligo (phenylenevinylene)s: On the detection of polaronic and bipolaronic states
Authors: Schenk Rainer , Gregorius Heike , Müllen Klaus
Published: December 2004

Communication: The effective conjugation length of poly(phenylenevinylene) an important conducting polymer, can be estimated by extrapolation of the results of UV/VIS/NIR studies of the radical anions and dianions of the soluble, well‐characterized oligo(phenylenevinylene)s shown in the figure. This information, in turn, is usefull in describing the mechanism of conduction in the polymer.

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Talking point. Intrinsically conducting polymers: A critical stage in research strategy?
Authors: Wessling Bernhard
Published: December 2004

Research News/Talking Point: Is the euphoria some attach to the prospects for conducting polymers misguided? Or is it the case that the wrong approach has been adopted for the research strategy? These two questions are addressed as the first commercially available intrinsically conducting polymer blend reaches the market.
Correlation between primary chemical structure and property phenomena in polycondensates
Authors: Sommer Klaus
Published: December 2004

Polycondensates (polycarbonates (PC), polyetherketones (PEK), and polyethersulfones (PES) in the present context) have an important share of the market for engineering and high‐performance thermoplastics. A knowledge of the relationships between the chemical structures of monomers and the properties of the polymers is an important prerequisite for the development of new plastics and the improvement of existing ones.

These relationships can be investigated through the characterization of systematically varied polycondensate structures, and by the application of theoretical simulation methods developed to provide a better understanding of the propertydetermining structural elements and for the prediction of polymer characteristics.

This article presents results relating to structure–property correlations (including various experimental results), static simulations of the amorphous polymer solid (“amorphous cell”) type, and dynamic Monte Carlo lattice simulations using the bond fluctuation algorithm.
Inorganic materials V. Ceramic materials possessing high thermal conductivity
Authors: Partridge Graham
Published: December 2004

Inorganic Materials V: Insulating dielectric materials which prossess a high thermal conductivity are required for the dissipation of heat from electrical and electronic equipment. As dissippation requirements increase with the miniaturization of circuitry, materials such as diamond, boron nitride, and silicon carbide are being used to replace alumina. The various materials and their applications are discussed.
Polymers for Nonlinear Optics
Authors: Buckley Alan
Published: December 2004

Nonlinear optical (NLO) materials provide the basis for an array of active optical devices under development throughout several high technology industries. Applications would include communications, data storage, and computing. Active optical devices can be used to alter light in order to encode or direct information in a number of ways. While the applications of optical technology such as fiber optics, optical storage and optical displays have identified a need for such devices, material properties have so far limited their introduction. Intensive, world‐wide, development of specifically designed polymers appears to offer the most attractive solution.
Crystal recognition at inorganic–organic interfaces: Nucleation and growth of oriented BaSO4 under Compressed Langmuir Monolayers
Authors: Heywood Brigid R. , Mann Stephen
Published: December 2004

Controlling the size and oriented nucleation of inorganic cyrstals (e.g. see figure) through using organized assemblies of macromolecules can lead to new materials with interesting properties. In this paper, the general importance of stereochemical recognition in monolayer‐induced inorganic crystallization is examined by investigating the influence of three different anionic head groups on the oriented nucleation of BaSO4

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Crystal structure of 4,4′,3″,4‴‐Tetramethyl2,2′:5′,2″:5″,2‴‐tetrathiophene: A comparison with the conformation in solution
Authors: Barbarella Giovanna , Zambianchi Massimo , Bongini Alessandro , Antolini Luciano
Published: December 2004

Are thiophene rings and chains more easily deformed than those in polyphenylene, polyfuran and polypyrrole? The conformation has great influence on the conjugation lenght of the polymers and therefore on their optical and electronic properites. Data obtained from an extremely rare X‐ray structure determination of an α, α'‐conjugated oligothiophene is comapared with that obtained from solution studies and both are discussed in light of MMP2 force‐field calculations.
Reversed vesicles from biocornpatible surfactants
Authors: Kunieda Hironobu , Nakamura Kazuyoshi , Infante Maria Rosa , Solans Conxita
Published: December 2004

The combination of hydrophilic and lipophilic amphiphiles and the addition of a small amount of water is demonstrated to be an effective method for the production of inversed vesicles (see figure) from biocompatible surfactant systems. Stable reversed vesicles would have applications in, for example, foods, medicines and cosmetics.

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Progress towards processible materials for light‐emitting devices using poly(p‐phenylphenylenevinylene)
Authors: Vestweber Horst , Greiner Andreas , Lemmer Ulrich , Mahrt Rainer F. , Richert Ranko , Heitz Walter , Bässler Heinz
Published: December 2004

Molecularly doped polymers are replacing inorganic photoreceptors in modern electrophotography. A future aim is to replace inorganic materials in light‐emitting diodes, but this required polymers that luminesce and are also processible in teir polymeric from. A promising candidate is poly(p‐phenylphenylenevinylene), shown in the figure.

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Synthesis and reduction of 1,4‐phenylene‐bridged oligoporphyrins
Authors: Hammel Dirk , Erk Peler , Seliuler Barbara , Heinze Jürgen , Müllen Klaus
Published: December 2004

The charge‐storage capability of oligoporphyrins (for example that shown in the figure) have been investigated. This has been made possible by the development of a straightforward synthesis of aryl‐substituted dipyrromethanes.

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Polyrotaxanes: Molecular composites derived by physical linkage of cyclic and linear species
Authors: Gibson Harry W. , Marand Hervé
Published: December 2004

Molecular composites consisting of cyclic molecules whose cavities have been pierced by linear molecules (see Figure) were discussed as early as 1910. However, recently interest in these molecules, which are known as rotaxanes, and their polymeric derivatives has intensified due to their unique property profiles which cannot be compared with those their components. Progress with rotaxanes and related compounds such as catenanes is reviewed.

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Imaging individual particles in concentrated colloidal dispersions by confocal scanning light microscopy
Authors: van Blaaderen Alfons
Published: December 2004

The study of colloidal dispersions is important in many areas, such as ceramics and electrorheological liquid research. Techniques such as high‐resolution electron microscopy, which must be used in a vacuum, and light microscopy with its lower resolution and the fact that out‐of‐focus information contributes to the image have severe limitations in this work, many of which are avoided through the use of confocal scanning light microscopy. The pros and cons of the technique and its applications are discussed.
Is there a colloid in every solution‐processable conducting polymer?
Authors: Aldissi Mahmoud
Published: December 2004

Quite often there is confusion regarding the definition of a solution, especially when conducting polymers are being discussed. Solvents containing particles with sizes below that of the wavelength of visible light will appear to be clear solutions but of course are not. This question has great significance in the definition of these materials and their study and processing.
(Me5C5)SiH3 and (Me5C5)2SiH2 as precursors for low‐temperature remote plasma‐enhanced CVD of thin Si3N4 and SiO2 films
Authors: Dahlhaus Jürgen , Jutzi Peter , Frenck Hubert‐Joachim , Kulisch Wilhelm
Published: December 2004

Silicon nitride (Si3N4) and silica (SiO2) thin films are of interest for applications in microelectronics and optics. Non‐hazardous alternatives to silane (SiH4) as the silicon precursor in the chemical vapor deposition (CVD) of these materials are in attractive target for research. It is shown that pentamethylcyclopentadiene‐substituted dilanes offer the opportunity to tailor precursors for particular CVD requirements.
AlH3(NMe3)2—a useful precursor to AlN
Authors: Rockensüß Wilfried , Roesky Herbert W.
Published: December 2004

The high‐performance ceramic aluminum nitridehas a high resistance to heat and aggressive media. These properties depend to a large degree on the purity of the material. As a result much effort has been invested in the search for new precursors to AlN for use in methods such as metal‐organic chemical vapor deposition (MOCVD). The figure shows pure AlN powder produced from the title compound in an ammonia atmosphere.

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Strengthening glasses and ceramics: Composite technology
Authors: Partridge Graham
Published: December 2004

Composite technologyoffers the opportunity to provide a large number of interfaces in a material which deflect crack fronts and dissipate the energy of fracture. Part II of this discussion examines the various types of composites, for example particle or whisker reinforcement, and analyzes their performance profiles with a special emphasis on the strengthening of glasses and glass‐ceramics.
Scanning tunneling microscopy of nanoscale electrodeposited superlattices
Authors: Switzer Jay A. , Golden Teresa D.
Published: December 2004

Artificially layered superconductor materials based on crystalline multilayer structure are of potential interest due to the unusual quantum effects which could be expected in materials of this type. Scanning tunneling microscopy has recently been used (e.g. see Figure) to measure the modulation wavelength (the bilayer thickness) and to estimate the composition profile in such superlattices.

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SERC–RUSTI: A new approach to strategic research and technology transfer
Authors: Clark David T.
Published: December 2004

Technology transfer is a crucial step in research and development, and in many cases it is the justification for continued funding of basic research programs. Several models have been proposed for nurturing the conversion of basic ideas into commercially interesting work, examples being the German Fraunhofer Institutes. Here, a new British solution is presented which is based on a cooperation of the Science and Engineering Research Council (SERC) and, primarily, ICI.
Photoinduced generation of noncentrosymmetric structures in glassy liquid crystalline polysiloxanes for second harmonic generation
Authors: Anneser Hans , Feiner Franz , Petri Andreas , Bräuchle Christoph , Leigeber Horst , Weitzel Hans‐Peter , Kreuzer Franz‐Heinrich , Haak Oliver , Boldt Peter
Published: December 2004

Poling nonlinear optical materials using light is reported. The new method, which combines a light‐ and an electrical‐field effect and is effective on glassy solid‐state materials, could in future be integrated into standard lithographic technology to produce, for example, nonlinear optical waveguides by irradiating through a mask when the electric field is switched on.
Photosensitized cross‐linking of Langmuir–Blodgett multilayers based on copoly(glutamate)s
Authors: Iida Shigeki , Schaub Mattias , Schulze Margit , Wegner Gerhard
Published: December 2004

Rod‐like polymers of overall cylindrical shape dressed with a skin of flexible short side chains have been shown to be versatile building blocks for supramolecular structures. This paper describes the production of “molecular composites” based on such rigid rods, the mesoscopic structure of which is shown in the Figure.

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Electrochemical processing of electrically conductive polymer fibers
Authors: Li Shulong , Macosko Christopher W. , White Henry S.
Published: December 2004

Macroscopic fibers of conducting polymers could be woven into lightweight antistatic fabrics, used as electrodes in batteries, or employed in light‐emitting displays. For this to be possible the fibers will need to exhibit high strength and flexibility. Here, an electrochemical process is presented which is based on the use of hydrodynamic forces to control the direction of polymer deposition. The process also has potential for application to other organic conductors and superconducting oxides.
A Few‐Monolayer Organic Rectifier
Authors: Martin A. Scott , Sambles J. Roy
Published: December 2004

An electrical building block whose properties depend solely on the molecular structure of its constituents, for example a rectifier, has been a research goal in molecular electronics for some time. The ultimate aim is to be able to address one molecule, and the rectifier described here, based on a few monolayers of C16H33γQ3CNQ is a step in the right direction.
Engineering oxide–oxide and metal–oxide microstructures in directionally solidified eutectics
Authors: Revcolevschi Alexandre , Dhalenne Guy
Published: December 2004

Very regularly aligned composite structures made of the two phases of a eutectic can be fabricated by unidirectional solidification of eutectics from the melt. A recent innovation is the use of chemical reactions taking place at the eutectic interface to produce new aligned composite materials. An example of this can be seen in the Figure, an SEM micrograph of an Ni/NiO interface showing long forks of Ni in an oriented NiO–ZrO2(CaO) eutectic.

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Metathesis Polymerization: ROMPing towards new materials
Authors: Gibson Vernon C.
Published: December 2004

The introduction of a new generation of metathesis initiators (see Figure) in which the active site is incorporated within a relatively robust transition metal complex has had a significant impact on polymer synthesis. Key recent developments in the types of materials accessible, the control over microstructure possible, and the advantages of well‐defined initialtors for the design and synthesis of new materials are reviewed.

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A new class of planar‐locked polyene dyes for nonlinear optics
Authors: Cabrera Ivan , Althoff Olaf , Man Hong‐Tai , Yoon Hyun N.
Published: December 2004

A combination of strategies for optimizing the molecular hyper‐polarizability have been employed in the design of the molecules reported here: an aromatic moiety is linked to a planar‐fixed polyene chain. The synthesis and nonlinear optical (NLO) characterization (absorption and electric‐field‐induced second harmonic generation) of the materials are described and their NLO properties compared —Favorably—with those of 4′‐dimethylamino‐4‐nitrostilbene, the prototypical organic material for electrooptic devices based on poled polymers.
Induction of bidimensionality in mixed CuTi perovskites
Authors: Palacín María Rosa , Fuertes Amparo , Casañ‐Pastor Nieves , Gömez‐Romero Pedro
Published: December 2004

Control of structure and order in oxides is essential for the design of new superconducting cuprates. The intergrowth of perovskite and rock salt layers, as found in bismuth, thallium and, very recently, the record breaking mercury cuprates, is just one way to induce bidimensionality. Defect “all perovskite” oxides, such as Ln2Ba2C2Ti2O11 (Ln = La, Nd, Eu) are discussed as examples of a crystal ‐chemical approach to the induction of bidimensionality and order in mixed perovskite oxides of copper.
Fascinating phenomena in Surfactant Chemistry
Authors: Hoffmann Heinz
Published: December 2004

An amphiphilic compound such as a surfactant molecule is a very simple molecule. Yet, when dissolved in water, it spontaneously self‐assembles into a multitude of micellar structures such as globules, rods, disks, and vesicles. Even in dilute solutions containing only about 1 % of surfactant, these primary structures can organize themselves on a macroscopic scale so that the whole system in a test tube can be completely ordered. Such systems can have very remarkable macroscopic properties, for example, a yield stress, complex fluid behavior, or iridescence under illumination.

The shape of the micellar structures is always determined by the area a that a surfactant molecule occupies at a micellar or bulk interphase. This area can be controlled or tuned by the mixing ratio X between surfactants or between surfactants and cosurfactants. The different assemblies which then result with the variation of X are discussed, together with the macroscopic properties of the systems and some applications where these properties are of use.
Electropolymerization of thiophene derivatized with a mesogenic substituent
Authors: Thobie‐Gautier Christine , Bouligand Yuves , Gorgues Alain , Jubault Michel , Roncali Jean
Published: December 2004

The synthesis of a new mesogenic thiophene derivative is reported. The monomer, which exhibits interesting mesophase properties, contains a p‐cyanobiphenyl group that is electronically and sterically decoupled from the thiophene ring by means of an octyl spacer. Electropolymerization of this monomer produces a polymer with conjgation lenght, conductivity, and electroactivity comparable to those of poly (3‐alkylthiophenes). The use of indirect substitutional effects to control the long‐range order and dimensionality of conducting polymers is discussed.