bluuebunny/crossref_metadata_2025 huggingface dataset:
Amyloglucosidase immobilized on acrylic supports
Authors: Maxim S. , Flondor A. , Bunia I.
Published: December 2004

This paper deals with the study of the behaviour of Amyloglucosidase covalently immobilized on acrylic supports in the maltodextrin hydrolysis process. The specific catalytic activity of the different immobilized Amyloglucosidase preparations critically depends on their protein content. The maltodextrin hydrolysis in the presence of the immobilized Amyloglusidase is a diffusion‐controlled process. The simulated operational stability of the immobilized Amyloglucosidase tested by the specific activity and the substrate conversion proves the conservation of the catalytic enzymatic activity.
L‐Phenylalanine production by double auxotrophic analogue resistant mutants of Arthrobacter globiformis
Authors: Maiti T. K. , Catterjee S. P.
Published: December 2004

A number of tryptophan plus tyrosine double auxotrophic mutants isolated by the NTG treatment of a glutamate producing strain of Arthrobacter globiformis were found to excrete phenylalanine in a mineral salt medium. By controlling the pH of the medium to near neutrality, the active growth period could be extended up to 72 h and more phenylalanine was accumulated compared to the unregulated culture where the growth period took up to 48 h. Under optimum culture conditions, the best double auxotroph (TT‐39) produced 3 g phenylalanine/l. Further improvement of phenylalanine production has been achieved by the step‐by‐step isolation of a mutant resistant to the phenylalanine analogues p‐fluorophenylalanine (PFP) and β‐2‐thienylalanine (TA) from the TT‐39 strain. Under optimum culture conditions, the best double auxotrophic analogue resistant mutant TT‐39 PTr‐21 yielded 8.7 g/l phenylalanine.
Fermented tempeh‐like products as useful way of utilizing legume seeds
Authors: Piskorz B. J. , Nowak J. , Szebiotko K.
Published: December 2004

The in vitro effect of fermented tempeh‐like food on intensive flatulence caused by intestinal bacteria after consuming soybeans (Glycine max) was studied.

Six fungi strains of Rhizopus and Actinomucor were tested. Rhizopus oligosporus NRRL 2710 proved to have the highest antibacterial activity. In vitro tests vs. Clostridium perfringens 546 showed that the soybean extract from the food fermented with the fungi mentioned above in about 80% of the experiments slowed the bacterial growth rate remarkably. The homogenization of tempeh‐like food increased its antimicrobial activity. Cultures of Rh. oligosporus NRRL 2710 grown on the brewery wort medium did not show any antibacterial activity.
Investigations of subtilisin (Novo type) immobilization on cellulose by means of various methods of support activation
Authors: Trzmiel T. , Galas E. , Fortak M.
Published: December 2004

The immobilization of subtilisin, Novo type, on WHATMAN cellulose activated by the glutaraldehyde, diisocyanate, diazo‐coupling, and S‐triazine method, and on a dialdehyde derivative of cellulose has been studied. The best results of proteinase immobilization were achieved when cellulose was activated by hexamethylene diisocyanate. The preparations of a proteolytic activity of 70 PU/g of support and of an esterase activity of 2.3 EU/g of support were obtained with 14% and 38% yield, respectively.
Fractionation of dextran solutions by cross‐flow filtration
Authors: Michelena G. , Bell A. , Rivas E. M.
Published: December 2004

The use of ultrafiltration to fractionate dextran solutions in order to obtain fractions for the synthesis of dextran derivatives was investigated.

Several experiments were carried out in two available commercial ultrafilters. The operation was evaluated by the recovery yield and process time.

Dextran solutions can be fractionated being concentrated up to 9 fold in a PM30, but no more than double in a PM5 hollow fibre membrane cartridge.
Growth control and ppGpp synthesis in Brevibacterium flavum cells at various medium mixing rates and aeration intensities
Authors: Ruklisha M. , Labane L. , Viesturs U.
Published: December 2004

Under the conditions of various aeration and medium mixing intensities (even at a constant medium oxygen partial pressure value), the variations in the RNA synthesis as well as the growth rate of lysine producing Brevibacterium flavum strains are inversely correlated with the ppGpp concentration in the cells.

An increase in the ppGpp synthesis and a decrease in the RNA content in the cells was observed in the cases of a low cell energy charge value (lower than 0.6). This took place in the cases of bacterial cultivation at a low or very high medium aeration and mixing intensity. Hence, the energy production in the cells, the ppGpp synthesis and the growth control mechanism in Corynebacteria may be regarded as connected processes.
Degradation of synthetic lignin by the protoplasts of Phanerochaete chrysosporium in the presence of lignin peroxidase or manganese peroxidase
Authors: Sayadi S. , Odier E.
Published: December 2004

Lignin was mineralized in the experiments in which 14C‐lignin was incubated with lignin peroxidase or manganese peroxidase in a tartrate buffer in the presence of cycloheximide‐treated protoplasts obtained from the ligninolytic mycelia of Phanerochaete chrysosporium. The rate of lignin mineralization was dependent on the lignin peroxidase or manganese peroxidase concentration in the medium. In the experiments in which lignin was incubated with lignin peroxidase or manganese peroxidase, lignin was repolymerized irrespective of the presence of protoplasts mineralizing lignin, suggesting that an active degradation of lignin and repolymerization took place. Taking into account that lignin peroxidase and manganese peroxidase were the only extracellular enzymes in the experiments in which lignin was mineralized by the protoplasts, it is postulated that lignin peroxidase and/or manganese peroxidase can degrade lignin into small fragments which can then be further absorbed by the fungal cells and subsequently degraded to CO2.
Cloning and expression of the Neisseria meningitidis 5C outer membrane protein
Authors: Guillen G. , Leal M. J. , Alvarez A. , Delgado M. , Silva R. , Herrera L.
Published: December 2004

The 5C outer membrane protein, one of the N. meningitidis class 5 proteins, was preferably expressed in bacteria isolated from the nasopharynx and its role in adhering to the mucosal cells and invading them as well as the development of anti‐5C antibodies in healthy carriers was demonstrated. Anti‐5C monoclonal antibodies are bactericidal in the presence of the human complement. The immunodominant region of the 5C protein is highly conserved among the different strains of N. meningitidis, and the opc gene, which encodes the protein, does not seem to show antigenic variations.

Here the isolation of the opc gene from the Cuban strain B:4:P1.15 by PCR (Polymerase Chain Reaction) is presented. Under the regulation of the tryptophan promoter, the gene was cloned and sequenced in E. coli with a high level of expression and fused to the amino‐terminal end of the interleukin‐2 gene. In the dot‐blot experiments, the presence of the gene in those strains which did not express the protein in the whole cell ELISA was also detectable.
Continuous semi‐solid cultivation for the production of cellulase by Trichoderma reesei mutants using a polyurethane foam carrier and a liquid medium
Authors: Targonski Z. , Pielecki J.
Published: December 2004

The production of cellulase was investigated in semi‐solid state culture using the immobilized mycelium of Trichoderma reesei mutants on polyurethane foam impregnated with lactose medium. An extremely high value of about 2.6 FPU/ml was reached after the cultivation of T. reesei D‐78085 on a 0.5% lactose medium in continuous culture at a pH medium of 4.0 when a bioreactor with vertical polyurethane foam plates was used. The enzyme yield on lactose was 520 FPU/g of lactose metabolized in comparison with 160 FPU/g using a stirred tank bioreactor.
Stability of the pBR322 plasmid derivative pBB210 in Escherichia coli TG1 under non‐selective and selective conditions
Authors: Löser C.
Published: December 2004

The stability behaviour of the pBR322 plasmid derivative pBB210 with β‐lactamase gene and human interferon‐α1 gene in Escherichia coli TG1 was studied in chemostat cultures under non‐selective (medium without antibiotics), selective (medium with β‐lactam antibiotic ampicillin) and modified selective (medium with ampicillin and the β‐lactamase inhibitor sulbactam) conditions. Under non‐selective conditions, a behaviour typical of unstable systems was found. Under selective conditions, the behaviour predicted by the models was obtained – the fraction of plasmid‐bearing cells in the population approached a constant value which was dependent on the ampicillin concentration in the feeding and on the cell concentration in the chemostat. Under modified selective conditions, the higher the concentration of sulbactam in the medium was, the higher the fraction of plasmid‐bearing cells was in steady state conditions.
Effect of activated carbon on the biological treatment of oil‐water emulsions
Authors: Martienssen M. , Simon J.
Published: December 2004

Waste water, derived from the reprocessing of used emulsions or suspensions, contains high concentrations of emulsified mineral oil and stabilizers, as well as different additives that are needed during the treatment process.

Two stirred‐tank reactors and two fixed‐bed reactors were used to study the biodegradation of these waste‐water compounds during two‐stage biological treatment. The waste water was first proceesed in an activated sludge reactor to remove easily biodegradable substances. The effluent from the first stage was treated in three parallel operating reactors: an activated sludge tank containing different amounts of powdered activated carbon (PAC, between 0 and 2%), an upflow anaerobic fixed‐bed reactor and an aerobic fixed‐bed reactor (trickling filter). The results from the continuous treatment were compared with laboratory batch experiments.

About 60% of the influent TOC was reduced by the first activated sludge treatment. The removal efficiency increased to about 70% by using a second activated sludge stage. This degradation was comparable to the maximum degree of degradation measured in laboratory batch experiments. PAC addition to the second activated sludge tank resulted in increased degradation rates. The removal efficiency increased to about 76% when 0.1% PAC was added and to 96% with 1% PAC. The removal efficiency decreased to 84% when the proportion of PAC was further increased to 2%. Variations in the amount of PAC addition per unit influent volume in the range of 50 and 200 mg/l had no significant effect on the TOC removal.

Degradation models based on the MONOD‐type equation were found to be in close correlation with the results obtained from batch experiments. However, the biological removal rates measured in batch experiments did not reflect the removal capacity determined in continuous operating treatment systems.
Molar growth yields of Zymomonas mobilis on glucose after the transition from anaerobic to aerobic continuous growth
Authors: Zikmanis P. , Kruce R. , Auzina L.
Published: December 2004

An increase in the molar growth yield (YX/S = 14.3–20.3 g/mol) on glucose (25 mM) was achieved after the transition of Zymomonas mobilis ATCC 29191 from anaerobic to aerobic steady state growth at dilution rates of D = 0.31–0.40 1/h and under oxygen‐unlimited conditions. The transfer of anaerobically or aerobically grown steady state cells into a fresh medium resulted in the higher values of YX/S. A positive correlation was established between biomass and acetaldehyde yield within the range of 5–9 mM acetaldehyde in the medium. An inhibitory effect of the exogenously added acetaldehyde (Ki = 16.7 ± 2.8 mM) on the ATPase activity was observed in vitro, using cell‐free extracts of anaerobically grown Z. mobilis. The results obtained provide evidence that the increased values of biomass yield could be explained by the redirection of ATP usage during aerobic growth of Z. mobilis.
Reduction of halogenated derivatives of benzoic acid to the corresponding alcohols by Desulfovibrio vulgaris PY1
Authors: Bock M. , Kneifel H. , Schoberth S. M. , Sahm H.
Published: December 2004

Desulfovibrio vulgaris strain PY1 was isolated from a 3‐chlorobenzoic acid (3CBA) degrading anaerobic enrichment culture, using anaerobic Percoll density centrifugation. When grown on pyruvate (20 mM), in the absence of sulphate and under strict anaerobic conditions, this organism converted not only the co‐substrates benzoate (BA), 3‐amino‐BA and 3CBA to the corresponding alcohols but also ten other different halogenated benzoic acids, viz., 4‐Cl‐, 3‐Br‐, 4‐Br‐, 3‐I‐, 3‐F‐, 4‐F‐, 2,4‐di‐Cl‐, 2,5‐di‐Cl‐, 3,4‐di‐Cl‐ and 3,5‐di‐Cl‐BA. This was verfied with HPLC and GC/MS spectrometric analyses. The yields of the co‐substrate converted after 30 days of growth were between 20% and 88%, depending on the compounds which had been added at initial concentrations of 500 μM. Sulphate, sulphite, thiosulphate and disulphite inhibited the formation of 3‐Cl‐benzyl alcohol (3CBOH), i.e. a 97 to 99% inhibition, and nitrate and sulphur had no effect (a 7–10% inhibition). In cell‐free extracts, the reduction of 3CBA to 3CBOH required strict anaerobic conditions, pyruvate or H2 as electron donors and the addition of methylviologen (MV), FAD, FMN or ferredoxin as electron carriers. The specific activity of the reduction of 3CBA to 3CBOH in crude extract was 5.3 nmol/(mg protein min). The reaction was not inhibited by additions of sulphate or sulphite (5 mM), but was completely inhibited at concentrations of 10 mM 3CBA or 50 mM BA. A carboxylic acid reductase (aldehyde dehydrogenase), which acted on non‐activated 3CBA and was responsible for the reduction of 3CBA to 3‐Cl‐benzaldehyde, was found in the solube fraction (94% of the total activity). These results demonstrate that strain PY1 was able to effectively reduce a wide range of halogenated benzoic acids to the corresponding alcohols.
Flow cytometric monitoring of Rhodococcus erythropolis and Ochrobactrum anthropi in a mixed culture
Authors: Müler S. , Lösche A. , Mertingk H. , Beisker W. , Babel W.
Published: December 2004

The GRAM‐positive bacterium Rhodococcus erythropolis K2–3 and the GRAM‐negative Ochrobactrum anthropi K2–14 are capable of synergistically degrading 4‐(2,4‐dichlorophenoxy)butyric acid (2,4‐DB). The two strais execute this task in a symbiotic manner, but the nature of the interaction involved in the degradation is only partially understood as yet. An essential first step in elucidating the interaction is to be able to monitor the two strans separately, at the cellular level, within mixed populations. Therefore a method exploiting fluorescently labelled lectin probes was developed. Since Concanavalin A (Con A) binds specifically to R. erythropolis K2–3, it was selected and linked to the fluoresent dye Bodipy 630/650, which has an excitation maximum in the red part of the visible light spectrum. Forward light scatter (FSC) and DNA fluorescence from both strains were also measured to obtain simultaneous information about their physiological states. The three parameters were conveniently monitored by dual and triple excitation flow cytometry in conjunction with double fluorescent staining techniques. In addition, the strains were identified using an epifluorescence microscope. These techniques were found powerful tools for the population analysis of this mixed bacterial system.
Action as a dynamic property of the genotype × environment interation implications for biotechnology
Authors: Kennedy I. R.
Published: December 2004

The action resonance theory (ART), a hypothesis based on a logical extension of EINSTEIN's theory of Brownian movement, suggests that the genotype × environment interaction can be modelled as forceful encounters of the gene‐products of an organism with its environment. This model has implications for molecular and cell biology, morphogenesis, evolutionary development via mutation, the mechanism of natural selection and overall function of ecosystems, extending SCHRÖDINGER's programme for molecular biology. Action, a thermodynamic property with the same physical dimensions as angular momentum and PLANCK's quantum of action, is proposed to be reversibly generated as a result of the molecular exchange of quanta, which become resonant at equilibrium, corresponding to an optimum degree of entropy and action for living systems. Because the theory can potentially predict solutions to unsolved problems such as the folding of proteins it has strong implications for successful genetic modification of organisms and for biotechnology in general; the design of a programme of research to test this theory is proposed. A key element in this research programme, improving productivity and sustainability, would be the need to select genetically modified strains in the ecological environment or niche in which they are required to function.
Materials, research—current issues and future directions
Authors: Collette John W. , Miller Joel S.
Published: December 2004

Technological advances in Europe and the USA which culminated, 50 years ago, in the commercialization of Nylon opened the way for the full scale development of synthetic materials. The Advanced Materials Conference held in Wilmington, Delaware, USA, in October 1988 as part of this 50th anniversary celebration, covered a wide spectrum of issues in materials science. John Collette and Joel Miller, organizers of the conference, introduce a series of reviews based on the lectures which took place.
Control of polymorphism by ‘tailor‐made’ polymeric crystallization auxiliaries. Preferential precipitation of a metastable polar form for second harmonic generation
Authors: Staab Eugen , Addadi Lia , Leiserowitz Leslie , Lahav Meir
Published: December 2004

Polar crystals can display pyroelectricity, piezoelectricity and frequency doubling leading to second harmonic generation. These metastable polar polymorphs can be selectively precipitated to the exclusion of stable, non‐polar forms by the use of polymeric crystallization auxiliaries. The approach is based on the hypothesis that crystal nuclei assume structures very similar to those of the crystals into which they develop.
European cooperation: The COST 500 series
Authors: Gibbons Tom B.
Published: December 2004

Many areas of metallurgy and engineering have benefited through European cooperations set up under the Cooperation in Scientific and Technical Research (COST) program. Those sections of the program of relevance to materials scientists which include aspects of power engineering, corrosion, powder engineering, corrosion, powder metallurgy, rapid solidification and alloyus, are described and reviewed.
Organized systems in eilat
Authors: Herbstein Frank , Möhwald Helmuth
Published: December 2004

Frank Herbstein and Helmuth Möhwald report on the recent Gentner Symposium on Chemistry, a triennial meeting between German and Israeli scientists. Topics covered include crystals, liquid crystals, and LB films together with many other aspects of organized systems.
van der waals interactions in force microscopy
Authors: Hartmann Uwe
Published: December 2004

Due to its high sensitivity, scanning force microscopy offers the possibility to map minute van der Waals forces between microprobe and sample surface at high spatial resolution. A detailed theoretical analysis confirms that the interactions involved directly reflect near‐surface dielectric properties hardly accessible to conventional detection techniques. This opens a new field of application to modern scanned‐probe techniques: van der Waals microscopy.
Optical and surface‐analytical methods for the characterization of ultrathin organic films
Authors: Bubeck Christoph , Holtkamp Dieter
Published: December 2004

Review: The elemental and molecular composition of polymeric organic films can be studied using techniques such as secondary ion mass spectrometry (SIMS), infrared and Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS). These non‐destructive methods also reveal information on depth profiles, molecular organization, and interface effects. The techniques and improvemetns made specifically for the study of monolayers and LB films using vibrational spectroscopy are described.
Biomaterials highlights VIII. Percutaneous implants
Authors: Heimke Günther
Published: December 2004

Research News/Biomaterials Highlights VIII: Increase of the functional life of biomedical implants which extend through the skin or other body tissues, such as dental implants, and catheters, can be achieved by careful selection of materials and bioengineering approaches. Recent developments are discussed.
The Leeds/Bradford/Durham IRC in Polymer Science & Technology
Authors: Ward Ian M.
Published: December 2004

Essay: The structure and support of Interdisciplinary Research Centres (IRCs) is still the subject of debate in the UK. One point of view is that significant progress will be made through focusing efforts in particular areas of science and technology. On the other hand, some believe that concentrating available funding in restricted fields will be detrimental to research outside the centres. The Director of the IRC for Polymer Science and Technology, which was officially opened in October 1990, describes the new centre and discusses the pros and cons.
A guidance for stable metallic conductivity in copper salts of N,N‐dicyanobenzoquinonediimines (DCNQIs)
Authors: Erk Peter , Meixner Hubert , Metzenthin Tobias , Hünig Siegfried , Langohr Uwe , von Schütz Jost U. , Werner Hans‐Peter , Wolf Hans C. , Burkert Rainer , Helberg Hans W. , Schaumburg Gerhard
Published: December 2004

Communiction: Radical anion salts of 2,5‐substituted N,N'‐dicyanoquinonediimines (DCNQIs) with various counterions represent a new class of highly conducting organic materials. Among the copper salts of the DCNQIs (see figure) five new radical anion salts with stable metallic behavior are presented. A comparison of structural details with physical properties reveals their stable metallic state to be conserved by tight crystal packing, which is dependent on the size of the substituents on the DCNQIs.

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Screw dislocations: The key to high critical currents in YBa2Cu3O7?
Authors: Jaeger Herbert
Published: December 2004

Research News: Defects in high‐Tc superconductors recently observed with the aid of scanning tunneling microscopy could hold the key to increased critical current densities, a crucial requirement for power applications. The observation, by teams from the Los Alamos National Laboratory, and IBM Zurich, and origin of the defects (see Figure) are discussed.

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The electrochromic effect in cobalt oxide thin films
Authors: da Fonseca C. N. Polo , De Paoli Marco‐A. , Gorenstein Annette
Published: December 2004

Communication: Anodic electroprecipitation has been used to deposit thin films of cobalt oxide onto transparent, conducting glass substrates. The electrochromic effect, a reversible color change promoted by an electrochemical reaction, is demonstrated in the films making them of interest, as with WO3, V2O5 and other transition‐metal oxides, for application in dynamic, optically controlled devices.
Cross‐linking in water‐absorbent polymers
Authors: Engelhardt Fritz , Ebert Gerlinde , Funk Rüdiger
Published: December 2004

Super‐absorbant polymerss based on poly(acrylic acid) networks are formed by radical copolymerization of the monomer with small amounts of certain cross‐linking agents. The structure of the polymer network has a major bearing on the performance of the product. It can be influenced during the polymerization by severla parametes, among which the functiionality and the reactivity of cross‐linking agents are the most important. The various factorss involved are discussed.
Hexafluoroacetone in resist chemistry
Authors: Przybilla Klaus J. , Röschert Horst , Pawlowski Georg
Published: December 2004

Photo‐and radiation‐sensitive materials are used are resists in the fabrication of memory and logic devices. The 64 MB DRAMs, scchedules for 1995, will requre feature sizes below 0.5 μm (see figure). Deep‐UV lithography is a promising method of achieving these targets meaning that new resists with faovrable transmission and bleaching characteristics in this spectral region are required.

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Defect Spectroscopy in semiconductors
Authors: Grimmeiss Hermann G. , Kleverman Mats
Published: December 2004

Defects in semiconductors are used to control the concentration and lifetime of charge carriers which in turn determine the properties of the materials. The identification and characterization of the deficts is therefore of utmost importance. The various experimental techniques, including junction space‐charge techniques are briefly introduced before some recent highlights from work on II‐ ‐VI, III–V, and IV–IV compound semiconductors, based on the combination of several characterization methods are presented.
Conjugated polymers and the bending cantilever method: Electrical muscles and smart devices
Authors: Pei Qibing , Inganläs Olle
Published: December 2004

The reversible bending of bipolymer strips composed of a polymer layer (polyethylene) and a conjugated polymer layer (polypyrrole) due to volume changes in the polypyrrole on chemical or electrochemical doping is demonstrated. Several applications of such bipolymer strips in devices used to convert chemical or electrial energy into mechanical energy are presented.
Orthopedic reconstruction: Taking the right approach
Authors: Heimke Günther
Published: December 2004

Materials for hip joint replacements have to satisfy many requirements, some of which appear to be contradictory. How the materials and components used in the past have withstood the wear of ten years or more in the body is reviewed in this article. The dangers of ignoring “side effects” and relying on just one technique, which may cause problems in the long term, are discussed. Potential sources of future trouble are also identified.
Highly branched polymers
Authors: Kim Young H.
Published: December 2004

Well‐defined, large dendritic molecules with branches at almost every repeat unit have recently been shown to form ordered structures such as gels and liquid‐crystalline phases. The highly branched Highly Branched Polymers polyamide shown in the Figure forms, for example, a nematic phase as a 40 wt‐% solution in amides, and as a 60 wt‐% solution forms a gel static conditions but becomes fluid under shear stress.

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The synthesis and crystal structure of a liquid‐crystalline ester of 4‐carboxyphenylferrocene
Authors: Loubser Christa , Imrie Christopher , van Rooyen Petrus H.
Published: December 2004

Incorporation of ferrocene into a liquid crystal (see Figure) results in a material which offers the potential combination of the properties of an enantiotropic liquid crystal with NLO or magnetic activity. The compound demonstrates that monosubstituted ferrocene can be used to stabilize liquid crystal phases. Its LC properties and its X‐ray structure are discussed.

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Well‐aligned carbon nanotubules
Authors: Hwang Jyun‐Hwei , Hsu Wen‐Kuan , Mou Chung‐ Yuan
Published: December 2004

The alignment of carbon nanotubules greatly influences their transport properties, for example their electrical conductivity. Since these properties are important for potential applications in electronic devices, it is desirable to be able to control nanotube morphology during synthesis. An arc production method is presented that uses copper‐mixed graphite as the positive electrode, resulting in the degree of alignment shown in the Figure.

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A new conducting charge transfer complex from a model thiophene oligomer and a Keggin‐type heteropolyanion
Authors: Fabre Bruno , Bidan Gérard
Published: December 2004

A conducting charge transfer complex between a sexithienyl radical cation and a Keggin‐type heteropolyanion (PMo12O) has been synthesized and characterized. These large inorganic ions confer new properties on polymers to which they are linked, for example, multiple redox exchanges, paramagnetism, electrochromism, and catalytic action. The thiophene hexamer is the best compromise between a long‐conjugated system and a processable material, and can be considered a typical poly(thiophene) model, thus allowing a better understanding of the electronic interactions between the conducting polymer poly(3‐methylthiophene) and the dopant anion PMo12O.
Novel materials for non‐ablative optical recording
Authors: Detty Michael R. , Fleming James C.
Published: December 2004

Novel materials for optical data storage based on a new recording method are described. Instead of pits or refractive index changes being produced in the recording medium, marks are the result of the generation of near ‐IR absorbing dyes, which leads to a change in the absorption of light from the read laser. The new materials, thin films of tellurium (IV) dihalide bound in a glass together with a sensitizing dye, undergo thermal reductive elimination of halogen on expousure to laser radiation. This technique could ind applications in electrophotographic mastering.
High nuclearity magnetic clusters: Magnetic properties of a nine cobalt cluster encapsulated in a polyoxometalate, [Co9(OH)3(H2O)6(HPO4)2(PW9O34)3]16⊕
Authors: Galán‐Mascarós Jose Ramón , Gómez‐Garcia Carlos J. , Borrás‐Almenar Juan José , Coronado Eugenio
Published: December 2004

One goal in molecular magnetism is the synthesis of clusters containing large numbers of coupled spins. In the title heteropolyanion three reconstituted Keggin like fragments [PCo3 W9O40] are assembeled to increase the spin nuclearity. The Figure shows the idealizedstructure of the Co9 cluster, illustrating the connections through oxygen and HPO⊖ groups. Magnetic measurements and EPR spectra are presented, and the nature of the cluster ground state discussed.

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CVD routes to titanium disulfide films
Authors: Lewkebandara T. Suren , Winter Charles H.
Published: December 2004

Tis2 films, used in lithium batteries, can be prepared by a variety of methods, including several chemical vapor deposition (CVD) routs. The available CVD routes are briefly reviewed, together with the techniques used to check that the resulting films meet the stringent requirements of the lithium battery industry, for example. Solid‐state lithium batteries used in heart pacemakers require TiS2 thinfilms of high purity, denese packing, exact stoichiometry, and a preferred crystallographic orientation, all of which can be achived by CVD methods.
Room temperature synthesis of poly(2,5‐dimethoxy‐l,4‐phenylenevinylene) by the chloride sulfonium salt route
Authors: Xia Younan , MacDiarmid Alan G. , Epstein Arthur J.
Published: December 2004

The preparation of poly(p‐phenylenevinylene) and its derivatives has until now always involved a high temperature (200–300°C) conversion of the precursor polymer (see Figure) to the target polymer—a process that will cause problems in practical device fabrication. A room‐temperature conversion method is described in which HBF4 simultaneously converts and dopes the chloride sulfonium precursor polymer to the metallic conducting form in one step.

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Atomic resolution chemical analysis
Authors: Browning Nigel D. , Chisholm Matthew F. , Pennycook Stephen J.
Published: December 2004

Chemical analysis on an atomic scales is now possible using the scanning transmissionn electron microscope. The experimental setup (Fig.) allows electron transmitted through the speciment to be collected and analyzed in a variety of ways, permitting atomic resolution microanalysis of selected atomic columns. This will indicate how bulk materials properties are influenced by the atomic structure of interfaces and defects.

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Molecular recognition and chemoresistive materials
Authors: Swager Timothy M. , Marsella Michael J.
Published: December 2004

Conducting‐polymer‐based sensory materials systems are designed to exhibit ionochromic, electrochemical, and/or resistive responses to specific chemical signals. The integration of molecular recognition elements into them is described. Poly(bithiophene) undergoes a twisting of the polymer backbone upon ion complexation, producing a reduction in conductivity.
Multi‐property materials: Magnetism and NLO properties
Authors: Cléement René , Lacroix Pascal G. , O'Hare Dermot , Evans John
Published: December 2004

Transparent magnets are just one of the novel types of materials which can be imagined when the properties of several materials are combined cooperatively. Intercalation can provide an alternative to other methods such as sol‐gel techniques for the synthesis of hybrid organic‐inorganic composites and also offers the advantage of better crystallinity. Recent progress in the combination of magnetic and nonlinear optical properties in layered materials is traced.
Antiferroelectric liquid crystals
Authors: Nishiyama Isa
Published: December 2004

Antiferroelectric liquid crystals (AFLCs) were often first identified as antiferroelectric several years after the discovery of a new phase. This was the case for MHTAC (see Figure). The theory of the application of AFLCs as a tristable switch is outlined and the various types of AFLC materials described: low molecular mass (one of which is now commercially available), polymeric, and dimeric systems.

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Raman Scattering in Zeolites and molecular sieves
Authors: Brémard Claude , Bougeard Daniel
Published: December 2004

The diffusion and location of guests in zeolite frameworks can be studied in‐situ using Raman spectroscopy. For example, the location and orientation of crown ethers (e.g. Na⊕ 18C6, see figure) used as templates in the synthesis of faujasite polymorphs can be studied in the framework they have helped to form, and the subsequent calcination process leading to the final zeolite can also be followed using the technique.

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Chiral effects in the second‐order optical nonlinearity of a poly(isocyanide) monolayer**
Authors: Kauranen M. Martti , Verbiest Thierry , Persoons André , Meijer E. W. , Teerenstra M. N. , Schouten A. J. , Nolte R. J. M. , Havinga E. E.
Published: December 2004

The influence of chirality on the nonlinear optical properties of poly(isocyanide)s is examined. It is found that the chiral and nonlinear properties can occur on different levels of the molecular structure and can therefore be separately tuned, but that they still can be coupled together. The NLO properties of chiral molecules can also be enhanced significantly byoptimizing the magnetic contriutions to the nonlinearity, an important result for applicatons in electro‐optics.
Quality polymer science
Authors: Gregory Peter
Published: December 2004

Full Papers in Advanced Materials? No, but manuscripts of such articles are regularly received at the Editorial Offices of Advanced Materials and promptly returned to their authors with the suggestion that they are submitted elsewhere. A possible alternative journal for articles (including Full Papers) on polymer physics and chemistry is Acta Polymerica. The various types of contributions to this journal are presented and attention is drawn to the sample issue of Acta Polymerica that is included with Advanced Materials this month.
Polarized photoluminescence of oligothiophenes in nematic liquid crystalline matrices
Authors: Sariciftci N. Serdar , Lemmer Uli , Vacar Dan , Heeger Alan J. , Janssen Rene A. J.
Published: December 2004

The macroscopic alignment of an extended conjugated oligomer by the simple means of embedding it in a liquid crystalline matrix and utilizing the properties of the host is demonstrated. That the orientation of the oligothiophene, in this case α‐sexithiophenyl, can be dynamically switched with the host nematic lattice upon application of an electric field is observed by the switching of the polarized photoluminescence. This simple procedure for orientation opens up new areas for detailed study of this class of materials.
Scanning probe microscopy of polymeric methyltrioxorhenium
Authors: Mattner Mike R. , Herrmann Wolfgang A. , Berger Rüdiger , Gerber Christoph , Gimzewski Jim K.
Published: December 2004

The surface of polymeric methyltrioxorhenium (poly‐MTO), which is an intercalation compound with water layers as the guest in a lamellar host lattice, is shown by scanning probe techniques to consist of randomly intersecting crystalline regions with small crystallite facets. The edges of these facets exhibit steps (see Figure), the size of which can be explained in terms of the layered structure.

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Ripening and formation of microcrystals of oligo(cyclohexylidene) oxime derivative produced by spin‐coating: Atomic force microscopy study
Authors: ten Grotenhuis Erik , van der Eerden Jan , Hoogesteger Frank , Jenneskens Leonardus
Published: December 2004

Microcrystals are formed after a ripening period when an oligo(cyclohexylidene) oxime derivative is deposited on silicon wafers by spin‐coating. Results are presented related to this behavior, including atomic force microscopy images such as that shown here of crystals that had developed 3 h after deposition of the initial soft layer. AFM and X‐ray diffraction data are compared.

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Second harmonic generation with metal‐containing ferroelectric liquid crystals
Authors: Espinet Pablo , Etxebarría Jesús , Folcia César Luis , Ortega Josu , Ros María Blanca , Serrano José Luis
Published: December 2004

The second harmonic generation (SHG) parameters for metal‐containing ferroelectric liquid crystals are reported for the first time. Some of the materials, based on the structure shown in the Figure, exhibit reasonable NLO efficiencies despite the fact that the molecules themselves do not possess well‐defined donor–acceptor arrays.

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Efficient green electroluminescent diodes based on poly (2‐dimethyloctylsilyl‐1,4‐phenylenevinylene)
Authors: Kim Sung Tae , Hwang Do‐Hoon , Li Xiao Chang , Grüner Johannes , Friend Richard H. , Holmes Andrew B. , Shim Hong Ku
Published: December 2004

An exceptionally high photoluminescene efficiency (60%) is reported for the title compound, a nwe, solution‐processable derivative of PPV. It is shown that the compound can be used to make relatively efficient green electroluminescent diodes, and methods of further improving the efficiency of the device, e.g., incorporation of an electron‐conducting, hole‐blocking material, are described. Electroluminescence, photoluminescence, and UV‐vis absorptioni spectra are presented, together with the IV and light characteristics of the devices.
Microcontact printing with a cylindrical rolling stamp: A practical step toward automatic manufacturing of patterns with submicrometer‐sized features
Authors: Xia Younan , Qin Dong , Whitesides George M.
Published: December 2004

Microcontant printing using self‐assembled monolayers has been extended to the patterning of large areas by the introduction of a rolling elastomeric stamp (see Figure). The procedure is described and scanning electron microscope images of silver test patterns are presented. The ability to form large areas of micropatterns rapidly is important for potential applications in sensors, microelectrode arrays, consumer electronic systems, and supports for cell cultures.

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Photoswitched sexithiophenes: Towards switchable molecular wires
Authors: Lehn Jean‐Marie , Tsivgouli Gerasimos M.
Published: December 2004

A photoswitchable molecular wire based on a sexithiophene core is described that has potential as a light‐driven molecular switch. The synthesis route. UV‐vis spectra, and electrochemical behavior are presented for the compound, which behaves like substituted terthiophene in the open form and like substituted sexithiophene in the closed form. It is shown that interconversion between the open and closed forms can be achived using two different wavelengths of the visible region; applications are foreseen in organic electronic devices.
A ferrimagnetically coupled liquid crystal
Authors: Griesar Klaus , Athanassopoulou Maria A. , Bustamante Eduardoa Soto , Haase Wolfgang , Tomkowicz Zbigniew , Zaleski Andrzej J.
Published: December 2004

Ferrimagnetic coupling in a mesogen is reported for the first time for the compound MnIII[((OC12H25)4 TPP)](TCNE) · 2 touluene (where TPP = tetraphenyl porphyrin, TCNE – tetracyanoethylene), which displays liquid crystal properties above 381 K and ferrimagnetic properties below 21.4 K. The results from differential scanning calorimetry, X‐ray diffraction, and AC susceptibility studies are discussed. Evidence is presented for the presence of net magnetic moments at zero applied field.
Yttrium‐doped alumoxanes: A chimie douce route to Y3Al5O12(YAG) and Y4A12O9 (YAM)
Authors: Harlan C. Jeff , Kareiva Aivaras , MacQueen Brent , Cook Ron , Barror Andrew R.
Published: December 2004

Yttrium‐doped alumoxanes are demonstrated to be ideal precursors for ternary aluminum oxides such as yttrium aluminum garnet (YAG). The yttrium‐doped alumoxanes (see Figure), formed by the reaction of carboxylate alumoxanes with Y(acac)3 (acac = acetylacetonate), provide a chimie douce route to YAG that directly competes with the traditional sol‐gel synthesis and has the additional advantage of greater processability of the pre‐ceramic.

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Microscopy of Structural Ceramics
Authors: Rühle Manfred
Published: December 2004

The development of advanced structural ceramics, which are used in specific components working under extreme conditions, require their microstructural analysis. The microscopy of structural ceramics is reviewed, beginning with various imaging techniques. The important microstructural features of three ceramics—alumina (the Figure shows an internal sensor AFM image), zirconia, and silicon nitride—and several composites are briefly outlined. FIG.

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NLO‐polymers containing tert‐butyloxycarbonyl protecting groups: Modification after processing leading to thermally stable nonlinear optical materials
Authors: Dörr Michael , Zentel Rudolf , Sprave Martin , Vydra Jan , Eich Manfred
Published: December 2004

A new polymer for nonlinear optics (NLO) based on male‐imide/methylvinyliscocyanate precursor polymers is introduced. This side‐chain copolymer is cured after spin‐coating and before poling, which, by a thermally activated fragmentation reaction, leads to increased glass transition temperature, increased density of NLO chromophores, and reduced solubility. NLO materials will play an important role in optical telecommunications, but the problem of the chromophores relaxing back into the isotropic state must first be solved.
3D organized self‐assembled monolayer electrodes: A novel biosensor configuration
Authors: Sampath Srinivasan , Lev Ovadia
Published: December 2004

A leak‐free, reagentless biosensor for glucose is demonstrated as one application of the bulk modified electrode with three‐dimensional self‐assembled monolayers reported here. The preparation of the electrode and the electrochemical investigations of its behavior are described. It is shown that model enzymes can be incorporated in these materials so that the biomolecules retain their activity and the SAMs their dense structure and charge‐mediation properties. A range of electrochemical applications are foreseen for such electrodes.
A glass‐forming conjugated main‐chain liquid crystal polymer for polarized electroluminescence applications
Authors: Grell Martin , Bradley Donal D. C. , Inbasekaran Mike , Woo E. P.
Published: December 2004

Electroluminescence and liquid crystallinity: these are the properties of a new spacerless conjugated main‐chain liquid‐crystalline (LC) polymer reported here. The thermal and spectroscopic properties of the new glass‐forming poly‐fluorene with octyl side chains (see Figure) are described, showing that polarized electroluminescent multilayer devices should be possible.

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Mesoporous silica with micrometer‐scale designs
Authors: Yang Hong , Coombs Neil , Ozin Geoffrey A.
Published: December 2004

A “three‐way‐templating” strategy is proposed for the growth of patterned, mesoporous silica on a gold‐covered mica substrate. A model is suggested, as shown in the Figure, involving (from bottom to top) the co‐assembly of alkanethiol‐decorated gold surfaces, alkanethiol‐surfactant hetero‐bilayers, and surfactant‐silicate assemblies.

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Crystal engineering of molecular NLO materials
Authors: Wong Man Shing , Bosshard Christian , Günter Peter
Published: December 2004

Efficient second‐order nonlinear optical materials are produced by optimizing the orientation of non‐centro‐symmetrically packed donor–acceptor chromophores. Practical approaches for inducing the favored alignment, for example incorporation of chirality into the chromophore (as shown in the Figure) and H‐bond‐induced self‐assembly of ionic or molecular aggregates, are briefly reviewed.

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Additive fabrication of integrated ferroelectric thin‐film capacitors using self‐assembled organic thin‐film templates
Authors: Jeon Noo Li , Clem Paul , Jung Duk Young , Lin Wenbin , Girolami Gregory S. , Payne David A. , Nuzzo Ralph G.
Published: December 2004

The utility of non‐lithographic patterning methods for the integrated fabrication of prototypical thin‐film‐device architectures is demonstrated. An additive patterning technique based on printed organic thin films is used to fabricate ferroelectric capacitors consisting of a Pt/PZT/Pt thin‐film structure, where PZT is lead zirconium titanate. This type of material, which has applications in high performance information storage, micromachine, and thermal imaging devices, cannot be created using the conventional fine‐scale patterning methods.
Adjacent reentry of folded polydimethylsilane polymer chains
Authors: Boyd Robert D. , Badyal Jas Pal S.
Published: December 2004

How does the polymer chain fold when polymer single crystals are grown? Evidence from AFM images of the surface structure of polydimethylsilane crystals is presented that suggests the adjacent recently model, in which the chains are regularly folded. Making hairpin turns at the surface (see Figure), describes the process better than the random (switchboard) model, in which an amorphous overlayer is produced.

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Beyond the hemicylindrical micellar monolayer on graphite: AFM evidence for a lyotropic liquid crystal film
Authors: Sokolov Igor , Yang Hong , Ozin Geoffrey A. , Henderson Grant S.
Published: December 2004

Micellar assemblies orient at graphite surfaces in the same way at the channels in mesoporous silica films. Evidence to suggest that the structural organization of the surfactant surface phase extends far beyond the hemicylindrical micellar monolayer located at teh water‒traphite interface is presented and details of the proposed assembly process given. An understanding of the origin of the coalignment between silica channels and graphite surface structures is the goal if this investigation, important for the design of mesoporous films and membranes with predetermined architectures.
Structural chemistry and guest inclusion of a new supramolecular material showing sensitivity to organic solvent vapors
Authors: Meinhold Dorit , Seichter Wilhelm , Köhnke Kurt , Seidel Jürgen , Weber Edwin
Published: December 2004

Clathrate formation—the formation of crystalline inclusion compounds—is one approach to chemical sensing of vapors and gases. The synthesis of a new diol host compound is described and absorptive clathrate formation and thermal clathrate decomposition are reported for acetone as the guest. It is shown that the sorptive uptake of a guest vapor by the crystalline host compound is not merely surface adsorption but true clathrate formation, involving a solid‐state transformation. It is suggested that the use of the host as a chemical sensor is not far off.
Solid‐state droplet laser made from an organic blend with a conjugated polymer emitter
Authors: Berggren Magnus , Dodabalapur Ananth , Bao Zhenan , Slusher Richart E.
Published: December 2004

Lasers based on organic materials have been produced with a wide range of resonator design and in a variety of geometries. A new strategy is presented for fabricating permanently near‐spherical whispering gallery mode (WGM) lasers from a blend of PPV7 and PBD (see Figure) by a melting and resolidification process. The thresholds and quality factors of these resonators are estimated and discussed.

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