bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrification in a packed bed bioreactor integrated into a marine recirculating maturation system under different substrate concentrations and flow rates
Authors: Kumar V. J. Rejish , Joseph Valsamma , Vijai R. , Philip Rosamma , Singh I. S. Bright 
Published: March 2011

AbstractBACKGROUND: A packed bed bioreactor (PBBR) activated with an indigenous nitrifying bacterial consortia was developed and commercialized for rapid establishment of nitrification in brackish water and marine hatchery systems in the tropics. The present study evaluated nitrification in PBBR integrated into a Penaeus monodon recirculating maturation system under different substrate concentrations and flow rates.RESULTS: Instant nitrification was observed after integration of PBBR into the maturation system. TAN and NO2‐N concentrations were always maintained below 0.5 mg L−1 during operation. The TAN and NO2‐N removal was significant (P < 0.001) in all the six reactor compartments of the PBBR having the substrates at initial concentrations of 2, 5 and 10 mg L−1. The average volumetric TAN removal rates increased with flow rates from 43.51 (250 L h−1) to 130.44 (2500 L h−1) gTAN m−3 day−1 (P < 0.05). FISH analysis of the biofilms after 70 days of operation gave positive results with probes NSO 190 ((β ammonia oxidizers), NsV 443 (Nitrosospira spp.) NEU (halophilic Nitrosomonas), Ntspa 712 (Phylum Nitrospira) indicating stability of the consortia.CONCLUSION: The PBBR integrated into the P. monodon maturation system exhibited significant nitrification upon operation for 70 days as well as at different substrate concentrations and flow rates. This system can easily be integrated into marine and brackish water aquaculture systems, to establish instantaneous nitrification. Copyright © 2011 Society of Chemical Industry
A practical parametrical characterization of the Fenton and the photo‐Fenton sulfamethazine treatment using semi‐empirical modeling
Authors: Pérez‐Moya Montserrat , Mansilla Héctor D. , Graells Moisès 
Published: March 2011

AbstractBACKGROUND: Sulfamethazine (SMT) has received little attention in the water treatment literature. Yet, SMT is among the non‐biodegradable substances increasingly found in aqueous media and affecting both public health and wastewater treatments. For a long time, advanced oxidation processes (AOPs) were studied via pure empirical modeling, although the surface response models resulting from lumped information (TOC, COD, etc.) present limitations regarding extrapolation and optimization. Conversely, detailed first‐principles modeling may not be affordable due to the computational burden and the chemical analysis needs. Thus, a balanced approach may be practical in many cases.RESULTS: Experiments on SMT solutions (500 mL, 50 mg L−1) were performed under conditions set by an experimental design. A set of replicated degradation time‐profiles (TOC and SMT concentrations) was obtained and a semi‐empirical kinetic model was fitted to these data to determine maximum conversion and kinetic rate.CONCLUSIONS: SMT can be completely degraded from water via photo‐Fenton treatment. Conditions for this treatment were investigated and its outcomes were systematically characterized by a simple kinetic model and two lumped parameters, conversion and kinetic rate. Both, the model and the corresponding parametrical characterization are introduced as a means to discriminate the most efficient treatment conditions in a practical and efficient way. Copyright © 2011 Society of Chemical Industry
The hyal and ventral branchial muscles in caecilian and salamander larvae: Homologies and evolution
Authors: Kleinteich Thomas , Haas Alexander 
Published: March 2011

AbstractAmphibians (Lissamphibia) are characterized by a bi‐phasic life‐cycle that comprises an aquatic larval stage and metamorphosis to the adult. The ancestral aquatic feeding behavior of amphibian larvae is suction feeding. The negative pressure that is needed for ingestion of prey is created by depression of the hyobranchial apparatus as a result of hyobranchial muscle action. Understanding the homologies of hyobranchial muscles in amphibian larvae is a crucial step in understanding the evolution of this important character complex. However, the literature mostly focuses on the adult musculature and terms used for hyal and ventral branchial muscles in different amphibians often do not reflect homologies across lissamphibian orders. Here we describe the hyal and ventral branchial musculature in larvae of caecilians (Gymnophiona) and salamanders (Caudata), including juveniles of two permanently aquatic salamander species. Based on previous alternative terminology schemes, we propose a terminology for the hyal and ventral branchial muscles that reflects the homologies of muscles and that is suited for studies on hyobranchial muscle evolution in amphibians. We present a discussion of the hyal and ventral branchial muscles in larvae of the most recent common ancestor of amphibians (i.e. the ground plan of Lissamphibia). Based on our terminology, the hyal and ventral branchial musculature of caecilians and salamanders comprises the following muscles: m. depressor mandibulae, m. depressor mandibulae posterior, m. hyomandibularis, m. branchiohyoideus externus, m. interhyoideus, m. interhyoideus posterior, m. subarcualis rectus I, m. subarcualis obliquus II, m. subarcualis obliquus III, m. subarcualis rectus II‐IV, and m. transversus ventralis IV. Except for the m. branchiohyoideus externus, all muscles considered herein can be assigned to the ground plan of the Lissamphibia with certainty. The m. branchiohyoideus externus is either apomorphic for the Batrachia (frogs + salamanders) or salamander larvae depending on whether or not a homologous muscle is present in frog tadpoles. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.
Simultaneous separation and analysis of water‐ and fat‐soluble vitamins on multi‐modal reversed‐phase weak anion exchange material by HPLC‐UV
Authors: Dabre Romain , Azad Nazanin , Schwämmle Achim , Lämmerhofer Michael , Lindner Wolfgang 
Published: March 2011

AbstractSeveral methods for the separation of vitamins on HPLC columns were already validated in the last 20 years. However, most of the techniques focus on separating either fat‐ or water‐soluble vitamins and only few methods are intended to separate lipophilic and hydrophilic vitamins simultaneously. A mixed‐mode reversed‐phase weak anion exchange (RP‐WAX) stationary phase was developed in our laboratory in order to address such mixture of analytes with different chemical characteristics, which are difficult to separate on standard columns. The high versatility in usage of the RP‐WAX chromatographic material allowed a baseline separation of ten vitamins within a single run, seven water‐soluble and three fat‐soluble, using three different chromatographic modes: some positively charged vitamins are eluted in ion exclusion and ion repulsion modes whereas the negatively charged molecules are eluted in the ion exchange mechanism. The non‐charged molecules are eluted in a classical reversed‐phase mode, regarding their polarities. The method was validated for the vitamin analysis in tablets, evaluating selectivity, robustness, linearity, accuracy, and precision. The validated method was finally employed for the analysis of the vitamin content of some commercially available supplement tablets.
Preparation and Characterization of Biodegradable and Electroactive Polymer Blend Materials Based on mPEG/Tetraaniline and PLLA
Authors: Liu Yadong , Hu Jun , Zhuang Xiuli , Zhang Peibiao , Chen Xuesi , Wei Yen , Wang Xianhong 
Published: March 2011

AbstractA novel PGTA diblock copolymer containing electroactive TEA and mPEG is described. Biodegradable PLLA/PGTA polymer blends are shown to be electroactive. Nanopores of different sizes can be formed on the surface of the polymer blends. An MTT assay shows that the PLLA/PGTA blends exhibited reduced cytotoxicity as compared to TEA due to the introduction of the biocompatible PLLA moiety. Cell culture results show that the cells grow better when they were adhered to the surface of the PLLA/PGTA blends. The 80/20 wt.‐% PLLA/PGTA blend shows the best biocompatibility and an electroactivity that accelerates the differentiation of rat C6 glioma cells. magnified image
Assessing the Variable Molecular Architecture of Poly(ethylene terephthalate) Under Reactive Modification by Melt and Dilute Solution Rheology
Authors: Tsenoglou Christos J. , Kiliaris Pantelis , Papaspyrides Constantine D. 
Published: March 2011

AbstractTwo simple methods are described that utilize melt or dilute solution rheology in characterizing transfomations in molecular architecture induced on an originally linear PET during the early stages of reactive extrusion. A plausible senario for the shape variation and relative difficulty of the new polymers formed is assumed, from which expressions for the evolving melt and intrinsic viscosity of the reacting PET are derived. The model is tested using two separate sets of viscometric data refering to PET modified at various degrees. Quantitative agreement is found between the two methods in estimating the composition of the various types of PET species present. magnified image
Enhanced Conductivity of Polyaniline by Conjugated Crosslinking
Authors: Yang Yuanyuan , Chen Shaozhu , Xu Lan 
Published: March 2011

AbstractA novel crosslinked conductive polyaniline (PANI) was prepared by chemically copolymerizing aniline (An) and p‐phenylenediamine (PPDA) with triphenylamine (TPA) as crosslinker, using ammonium peroxydisulfate (APS) as an oxidant. The effects of different preparation conditions on the electrical conductivity of polymers were systematically investigated by adjusting acid kinds, concentration, the ratio of APS/An, the mounts of TPA and PPDA. The crosslinked PANI displayed a conductivity increase of up to 25% compared with the linear one. Their structures were characterized by Fourier‐transformed infrared spectroscopy and X‐ray photoelectron spectroscopy, and the electrical conductivity was also tested by a typical four‐point probe (RTS‐8) technique. magnified image
Solid state NMR — A tool for studying molecular motion in polymers
Authors: Sillescu Hans 
Published: March 2011

AbstractAfter an introduction describing the development of 1H, 2H, and 13C solid state NMR two sections on 13C and 2H NMR, respectively, outline the physical background as related with molecular motion. Some representative examples demonstrate the potential of recent NMR techniques in polymer dynamics studies.
A survey on structure and properties of polymers with metal‐like conductivity
Authors: Wegner Gerhard 
Published: March 2011

AbstractThe structure of conducting polymers is discussed in comparison to simple, so‐called organic metals derived from naphthalene and similar arenes. In this context the conducting polymers are viewed as ion‐radical salts of the backbone‐units. This view is substantiated by recent results from X‐ray investigations on electro‐chemically oxidized p‐quaterphenyl as a model for poly (p‐phenylene), polypyrrol salts of detergent ions and oxidized, highly oriented polyacetylene. The stability and other properties related to possible applications can be understood based on these structural and chemical evaluations.
Structure‐property relations in linear and crosslinked liquid crystalline polymers
Authors: Canessa Guido , Reck Bernd , Reckert Gertrude , Zentel Rudolf 
Published: March 2011

AbstractThis paper reviews structure‐property relations in liquid crystalline side group polymers, as investigated by X‐ray scattering of fibres, by small angle X‐ray scattering in solution, by dielectric relaxation measurements and by melt rheology, as well as synthetic ways to “combined liquid crystalline polymers”. The synthesis of liquid crystalline elastomers from side group, main chain and combined liquid crystalline polymers is described. First structure‐property relations are discussed.
On the regulation of the interaction of synthetic polymers with blood
Authors: Valuev L. I. , Chupov V. V. , Platé N. A. 
Published: March 2011

AbstractThe interaction of polymeric hydrogels containing immobilized trypsin and heparin with serum, blood and model solutions of serum proteins has been studied. It has been shown that these binary systems have high haemocompatibility due to specific fibrinogen binding by immobilized heparin and the subsequent lysis of bound substrate by immobilized protease. The lysis is accelerated in the presence of serum albumin and such materials may be regarded as biologically active ternary polymers.
Stable metal‐carbene complexes as initiators for ring‐opening polymerization of cyclo‐olefins
Authors: Doherty Martin , Siove Alain , Parlier Andrée , Rudler Henri , Fontanille Michel 
Published: March 2011

AbstractThe use of stable metal‐carbene complexes to initiate the polymerization of norbornene allows to know the exact nature of active centers propagating the polymerization. Complexes showing an intramolecular coordination of a double‐bond on the transition metal atommagnified imageoffer a satisfactory compromise between stability and activity and are used to study the initiation step. It is shown that the kinetically limiting step of the process is the liberation of a coordination site in cis‐position with respect to the carbene carbon. The effect of several physical and chemical factors on the activity of initiator complex is studied. In particular, the mechanism of activation by Lewis acids is analyzed by 13C and 1H NMR on the system complex III/Al(C2H5)3.
Poly(organophosphazenes): Synthesis, unique properties, and applications
Authors: Allcock Harry R. 
Published: March 2011

AbstractPoly(organophosphazenes) are the first inorganic backbone polymers to be developed on a broad scale since the discovery of the silicones in the 1940's. Polyphosphazenes are synthesized by ring‐opening polymerization of cyclic halogenophosphazenes, followed by nucleophilic replacement of the halogen atoms in the polymer by organic units. Factors that affect the ring‐opening polymerization are discussed, together with the properties and uses of the new polymers.
Biomedical polymers from chiral lactides and functional lactones: Properties and applications
Authors: Vert M. 
Published: March 2011

AbstractConfiguration‐respecting ring opening polymerization of ester‐containing chiral cyclic monomers derived from metabolic compounds as lactic, glycolic and malic acids has a two‐fold interest. First, it can lead to stereoregular polymers and copolymers whose physical, mechanical and biological properties can be adjusted through structural parameters. Secondly, resulting polymers can be degraded to the metabolic precursors of repeating units. Prerequisites which have to be taken into account for the selection and the tailor‐making of bioresorbable polymers for applications in bone surgery and drug delivery are presented. Emphasis is made on structure‐property relationships.
Epoxy resins. New results and developments
Authors: Lohse F. 
Published: March 2011

AbstractIn a survey the development of epoxy resin systems is described. During the past years countless formulations based on known structures were used, but only a relative small number of new epoxies and curing agents were investigated and only very few new compounds came on the market.A choice of these products will be discussed, also new latent accelerators and curing agents. By improvement of technical processes purer epoxies can be offered and toxicological risks could be strongly reduced. Especially new results in the fast growing field of photocrosslinking will be described. Besides iodonium, sulfonium and phosphonium compounds new arene iron salts and their behaviour will be presented.Generally, the trend in the epoxy field is to better heat resistant structures for new formulations in the field of adhesives and fibre‐reinforced materials, and to new photocrosslinking systems.
Polypyrrole as an electrode material for secondary lithium cells
Authors: Bittihn R. , Ely G. , Woeffler F. , Münstedt H. , Naarmann H. , Naegele D. 
Published: March 2011

AbstractPolypyrrole is a promising positive electrode material for the application in secondary lithium cells. The elemental analysis performed on electrochemically prepared polypyrrole films indicates a specific capacity of 82 Ah/kg. This specific capacity can be cycled in half cell experiments for many hundred times. The rate of self discharge of such an electrode is about 1%/day. On the basis of these results it will be shown that a lithium polypyrrole cell of optimal design may arrive at an energy density of about 40 ‐ 60 Wh/kg. First results obtained with practical cells of technical design confirm this statement.
Thin polymer films on semiconductors: From their protection to the realization of molecular electronic devices
Authors: Garnier Francis , Horowitz Gilles 
Published: March 2011

AbstractWhen homogeneously grafted as thin films on small band‐gap inorganic semiconductors (n‐GaAs, n‐CdS), organic conjugated polymers such as poly‐methylthiophene afford interesting new structures. In their doped conducting state, these polymer films bring a long‐term protection of these semiconductors against their photocorrosion in aqueous medium, and the subsequent inclusion of metallic aggregates in these films allows increased catalytic activity for achieving photoelectrochemical reactions. In their undoped semiconducting state, they lead to the realization of “organic‐on‐inorganic” p‐n junctions which show very low leakage current and high allowed current density. As photovoltaic cell, an energy conversion efficiency of 17.5% has been obtained under 100 mW.cm−2 irradiation with a p‐PMeT/n‐GaAs cell.
The larger number of work already devoted to organic conjugated polymers such as polyacetylene, polypyrrole, polythiophene, has shown that these compounds can be switched between a doped oxidized state, with a nearly metallic conductivity, σ ∼ 102‐103S.cm−1, and an undoped neutral state which presents semiconducting properties, σ ∼ 10−7 ‐10−9 S. cm−1. Either as free standing film or grafted on an electrode, these polymers exhibit interesting organic electrode properties which have been widely characterized. On the other hand much less is known on their behavior when deposited on inorganic semiconductors. In the following, this area will be discussed on two examples, the protection of narrow band‐gap semiconductors against their photo‐degradation in aqueous solution, and the new junction properties presented by “organic‐on‐inorganic” electronic devices.
Structure formation in polymer blends as a result of phase separation and deformation processes
Authors: Berger W. , Kammer H. W. 
Published: March 2011

AbstractPolymeric blends, which are materials consisting of two or more polymers, are gaining in practical importance and scientific interest. The properties of these materials are greatly affected by their state of miscibility. This paper reviews selected thermodynamic and rheological considerations regarding the phase behavior and the morphological control of polymer blends. Major emphasis is placed on the phase behavior of poly‐blends comprising random copolymers. ‐ The majority of polymer blends are microheterogeneous systems. There is consequently, a great need for control of the phase morphology during processing of immiscible polymers to achieve the desired property combinations. The key to this are both the microrheology of the phases and the macrorheology of the dispersion itself. In a qualitative way, one can establish that the ratio of the viscosities and the difference in the elasticities of the components determine sizes and shapes, respectively, of the phases indicating that the variety of morphologies observed in polymer‐polymer systems subjected to shearing has to be attributed to the viscoelasticity of each component. Furthermore, particular compositions are associated with changes in the morphology. This fact supports the particular compositions as an inherent feature of the melt rheology of polyblends.
Small angle X‐ray scattering pole figures of semicrystalline polymers obtained by synchrotron radiation
Authors: Röber S. , Bösecke P. , Zachmann H.G. 
Published: March 2011

AbstractA goniometer for measuring small angle X‐ray scattering pole figures by using synchrotron radiation has been constructed. In order to obtain the scattering in a large range of scattering angles, position‐sensitive detectors (Gabriel counter and vidicon system) are applied. The integrated intensity as well as the position and the half width of the maximum are determined as functions of the angle between the incident beam and the normal to the film surface of the sample. The time necessary to determine a pole figure was approximately 3 hours.Samples of poly(ethylene terephthalate) were drawn under different conditions: uniaxially and biaxially at 92°C under homogeneous deformation, and uniaxially at 40°C by necking. The influence of the drawing conditions on the orientation of the crystal lamellae was determined. The results of the small angle scattering are compared with pole figures obtained by wide angle scattering. In addition some results with polypropylene were obtained.The small angle X‐ray scattering is strongly affected by the limited size of the crystals and by the incomplete regular arrangement of the crystals. This gives rise to difficulties in the interpretation of the results. The problem will be discussed.
Influence of structure on the impact behaviour of nylon‐rubber blends
Authors: Borggreve R. J .M. , Gaymans R. J. , Luttmer A. R. 
Published: March 2011

AbstractBlends of nylon‐6 and EPDM rubber were prepared by reaction blending to study the influence of rubber concentration, rubber particle size and interfacial adhesion on the impact strength. Rubber particles induce a sharp brittle‐tough transition which is independent of the glass transition of the nylon matrix. Increasing the rubber concentration or decreasing the particle diameter shifts the brittle‐tough transition temperature for notched Izod impact tests to lower values.A toughening mechanism is proposed in which the interparticle distance, the rubber modulus and the temperature play crucial roles.
ESR and NMR studies of transients and micromechanisms occurring in initator systems for laser induced polymerization
Authors: Roth H. ‐Klaus , Leopold Detlev 
Published: March 2011

AbstractThe paper informs about the possibilities of studying the path‐ways of photolytically induced radical formation and of the first steps of radical reactions by methods of magnetic resonance. The investigations were carried out on initiator systems for laser induced polymerization containing anthraquinone. triethylamine and erythrosine in various solvents. The applied methods were time‐domain and steady‐state cw‐ESR, electron spin echo (ESE), 1H NMR and stimulated nuclear polarization (SNP). The chemically induced polarization of electron spins and nuclear spins (CIDEP and CIDNP) and their relaxation was used as main source of information about the fast laser—induced reactions.