bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal and Spatial Patterns of Epibenthic Macroinvertebrates (EMI) from the San Pedro Shelf, California: Ten‐Year Study
Authors: Maurer Don , Diener Douglas , Robertson George , Mengel Mike , Gerlinger Tom 
Published: February 2007

AbstractTemporal and spatial changes of epibenthic macroinvertebrates (EMI) were described from a ten‐year (1985–1995) trawl study on the San Pedro Shelf, California. Community measures including number of species, individuals, biomass, dominance (DI), evenness (J'), and diversity (H' and SR) per trawl were computed for eight trawl stations representing four isobaths. Two reference stations and a test station (located at an ocean outfall) were featured in statistical analyses examining whether the outfall had any effect on EMI. During the ten‐year period 127,389 individuals provided 106 EMI taxa. Water depth was the most important factor affecting EMI composition. Although some statistically significant differences in EMI community measures among trawl stations were found. differences between the outfall and both reference stations were either insignificant or inconsistent, providing no obvious ecological impacts attributable to the outfall.
Larval Size and Leaf Conditioning in the Breakdown of Nothofagus pumilio Leaves by Klapopteryx kuscheli (Insecta, Plecoptera) in a South Andean Stream
Authors: Albariño Ricardo J. , Balseiro Esteban G. 
Published: February 2007

AbstractThe effect of the shredder Klapopteryx kuscheli (Plecoptera, Austroperlidae) on the breakdown of Nothofagus pumilio leaves was studied in field experiments. Decay rates due to leaching and shredder activity were measured on conditioned and unconditioned leaves. Two sizes of shredder were tested in order to establish if the consumption per unit of shredder biomass varied with insect development. In three days weight losses due to leaching were 8.5%, and decay rates due to shredders were significantly higher than in control replicates. There were no differences in decay rates between conditioned and unconditioned leaves. Small larvae consumed more leaf biomass per unit of insect biomass than large ones. Growth efficiencies of K. kuscheli larva were low, but smaller larvae showed higher efficiencies than larger ones.
Competition between Phyto‐ and Bacterioplankton of Lake Balaton in Continuous Cultures
Authors: Shafik Hesham M. , Mastala Zoltán , Vörös Lajos 
Published: February 2007

AbstractAliquots of a water sample taken from the mesotrophic basin of Lake Balaton in August were incubated in three identical (2 liter) chemostats. Nutrients (35 μg PO4‐P · 1−1 week−1 and 350 μg NO3‐N · 1−1 week−1) were added by weekly pulses to the first culture and by continuous supply to the other two. The third culture was enriched continuously with Na‐acetate (5 mg · 1−1 week−1). Pulsed nutrient supply resulted in permanent coexistence of three algal species (Mougeotia sp., Synedra acus v. radians and Lyngbya limnetica) while the continuous supply (second culture) led to the predominance of Lyngbya limnetica. The Na‐acetate addition experiment showed, that in the absence of carbon limitation, picophytoplankton were able to compete successfully with bacteria. The results indicate that indigenous phytoplankton can only thrive when bacterial growth is limited by carbon.
Infra‐ and Circalittoral Soft Substratum Macrofaunal Assemblages of Kavala Gulf (Aegean Sea)
Authors: Papazacharias A. , Koukouras A. , Kevrekidis T. , Voultsiadou E. 
Published: February 2007

AbstractFive macrobenthic assemblages of the infralittoral and circalittoral zones located in the Gulf of Kavala, North Aegean, are described: (i) the assemblage of gravely sand with Parvicardium roseum and Clausinella brogniartii, (ii) the assemblage of sandy silt with Loripes lacteus and Nephthys hombergii. (iii) the clayey silt assemblage with Terebellides stroemi and Sternaspis scutata, (iv) the sandy silt assemblage with Amphiura chiajei and (v) the assemblage of silt with Labioleanira yhleni, the latter being described for the first time. Their composition is statistically tested, discussed in relation to abiotic factors, and compared with that of the corresponding assemblages from the Aegean and other Mediterranean and Atlantic areas.
Trace Metals in Tripton, Zooplankton, Zoobenthos, Reeds and Sediments of Selected Lakes in North‐Central Poland
Authors: Zauke Gerd‐Peter , Bohlke Jürgen , Żytkowicz Roman , Napiórkowski Pawel , Giziński Andrzej 
Published: February 2007

AbstractThe trace elements Pb, Cd, Cu and Zn were assayed in settling particles (tripton), biota (zooplankton, Asellus aquaticus, midge larvae, the moss Drepanocladius fluitans and the reed Phragmites australis) and profundal and littoral sediments from a dam reservoir of the Vistula River and a nearby forest lake and from six further lakes within the Masurian lake district and the Brodnica Park area. The amounts of metals in tripton differed greatly between lakes, while concentrations in zooplankton were almost homogeneous; only for an acidified clearwater lake (pH 4.8) were exceptional Pb and Cd levels recorded in zooplankton (56 mg Pb kg−1 and 12.8 mg Cd kg−1 d.w.). Similarly elevated levels were found in A. aquaticus, suggesting a metal‐mediated retardation in growth of isopods in this lake. Great variability was also noted for profundal sediments, with highest concentrations in the Vistula dam reservoir, reaching 9–12 mg Cd kg−1 and 580–730 mg Zn kg−1 d.w. Apart from these exceptional values, most of our data were well within the reported literature range. Nevertheless, only Cu concentrations in profundal sediments of the lakes investigated are (with two exceptions) smaller than threshold effect levels below which biological effects are unlikely to occur.
Upregulation of retinoic acid receptor‐β by the epidermal growth factor‐receptor inhibitor PD153035 is not mediated by blockade of ErbB pathways
Authors: Grunt Thomas W. , Tomek Katharina , Wagner Renate , Puckmair Klaudia , Kainz Birgit , Rünzler Dominik , Gaiger Alexander , Köhler Gottfried , Zielinski Christoph C. 
Published: February 2007

AbstractInhibiting epidermal growth factor‐receptor (ErbB‐1) represents a powerful anticancer strategy. Activation of retinoid pathways is also in development for cancer treatment. Retinoic acid receptor‐β—the tumor suppressor and main retinoid mediator—‐is silenced in many tumors. The ErbB‐1 inhibitor PD153035 cooperates with retinoic acid during growth inhibition and induces retinoic acid receptor‐β suggesting that ErbB‐1 controls retinoic acid receptor‐β. However, here we demonstrate that ErbB pathways are not involved in PD153035‐mediated retinoic acid receptor‐β‐upregulation. PD153035 inhibits ErbB‐1‐phosphorylation, whereas its derivative EBE‐A22 is inactive. Yet both inhibit cell growth and upregulate retinoic acid receptor‐β in ErbB‐1‐overexpressing (MDA‐MB‐468), moderately expressing (OVCAR‐3), ErbB‐1‐negative (MDA‐MB‐453) or ErbB‐negative cells (CEM, Jurkat). Both bind DNA, whereas the closely related ErbB‐1 inhibitors AG1478 and ZD1839, which are inactive on retinoic acid receptor‐β, do not significantly bind DNA. None of the other ErbB‐1/ErbB‐2 inhibitors tested (RG‐14620, LFM‐A12, AG879, AG825) affect retinoic acid receptor‐β. PD153035 decreases methylation of the retinoic acid receptor‐β2 promoter. In OVCAR‐3, it stimulates dislodgement of histone deacetylase 1 from the promoter and acetylation of histones H3 and H4. Consequently, PD153035 facilitates recruitment of RNA polymerase II to the promoter and stimulates transcriptional activity. Moreover, PD153035 increases the retinoic acid receptor‐β mRNA half‐life. No other retinoid receptor, nor estrogen receptor‐α, nor RASSF1A is upregulated by PD153035. Thus PD153035 induces retinoic acid receptor‐β by ErbB‐independent transcriptional and post‐transcriptional mechanisms. This report highlights a triple action for an ErbB‐1 inhibitor (ErbB‐1 inhibition, DNA intercalation, retinoic acid receptor‐β‐induction). Such multitargeting drugs bear great potential for cancer treatment. J. Cell. Physiol. 211: 803–815, 2007. © 2007 Wiley‐Liss, Inc.
Investigation of Stabilization and Kinetics in the Semi‐Continuous Emulsion Copolymerization of Vinyl Acetate and Butyl Acrylate using Carboxylic Monomers
Authors: Araújo Pedro H. H. , Sayer Cláudia , Caldas Elba , Santos Alexandre F. , Fortuny Montserrat 
Published: February 2007

AbstractThis work investigates the influence of carboxylic monomers such as acrylic acid (AA) and methacrylic acid (MAA) on the reaction rate and the colloidal stability during semicontinuous vinyl acetate (VA) and butyl acrylate (BA) emulsion copolymerizations. A number of copolymerization runs was carried out under different reaction temperatures and concentrations of AA and MAA. Samples were collected for off‐line analysis of particle size and conversion, allowing calculations of particle number values giving an indication of the particle stability. Additionally, partitioning analysis using conductometric and potentiometric titrations were performed in order to assess the distribution of carboxylic monomers among the main phases of the latex. Results showed that for both carboxylic monomers the increasing of the reaction temperature produces an increase in the coalescence rate and that the increasing of the concentration of these monomers leads to the increase in the amount of adsorbed COOH groups on the particle surface, which enhances latex stability. Nevertheless, when the concentration of methacrylic acid was increased a strong reduction of the polymerization rate was observed with a greater incorporation of acid groups buried in the particles.
Analysis of Conducting Poly(o‐methoxyaniline) Blends by Impedance Spectroscopy
Authors: Machado Wagner S. , Moreira José C. , Onmori Roberto K. , Wang Shu H. , Soares Demétrio A. W. 
Published: February 2007

AbstractImpedance measurements were carried out in flexible, conducting and semi crystalline films obtained by casting poly(p‐hydroxystyrene)‐b‐polyisoprene (PHS‐b‐IR) and p‐toluene sulfonic acid (TSA)‐doped poly(o‐methoxyaniline) (POMTS) mixtures from N,N‐dimethylformamide solutions. The measures ac were made in LCR Meter HP4284A equipment, in the range 102–106 Hz. The results were analyzed using a program in LabView platform for the attainment of the impedance arcs to obtain the conducting blends parameters. The obtained results had allowed evaluating some characteristics of studied conducting POMTS blends as conductivity ac, dielectric relaxation time, and capacitance. Analysis by optical microscopy (OM) allowed the observation of quasi‐spherical particles dispersed morphology for blends with 5 to 50‐wt% of POMTS. However, this morphology was not observed for blends presenting more than 50% of POMTS.
X‐Ray Study of Herbaspirilum Seropedicae GlnB Protein Adsorbed on Silicon
Authors: Lubambo Adriana Freire , Benelli Elaine Machado , Mazzaro Irineu , Yokaichyia Fabiano , Giles Carlos , de Camargo Paulo César 
Published: February 2007

AbstractGlnB‐Hs protein is a globular member of PII‐like family involved in the nitrogen control fixation in diazothoph organisms like H. seropedicae. In this work, GlnB‐Hs is deposited by spin‐coating on Si (111) and its self‐assembling is investigated by AFM (atomic force microscopy) and X‐ray at grazing incidence angles. GlnB‐Hs forms circular 100 nm to 150 nm wide face‐up donut shaped protein aggregates on silicon. Reflectivity and diffraction profiles from the protein deposits on Si(111) and Si(100), suggest ordered domains that are stable under the X‐ray beam and have d‐spacing compatible with protein dimensions already determined by classical protein crystallography.
Morphology of Poly(ethylene oxide)‐block‐Polycaprolatone Block Copolymer Micelles Controlled via the Preparation Method
Authors: Giacomelli Cristiano , Borsali Redouane 
Published: February 2007

AbstractBiocompatible poly(ethylene oxide)‐b‐polycaprolatone (PEO‐b‐PCL) micelles have been successfully tested in many fields as nano‐carries, especially in drug delivery. We demonstrate herein that using indirect dissolution methods to prepare PEO‐b‐PCL nano‐objects in water, copolymers with volume fractions of PCL (ϕPCL) ranging from 0.35 to 0.58 self‐assemble into spherical micelles when either DMF or THF is used as organic solvent to dissolve the diblocks before the micellization. Striking different, regular wormlike morphologies are however obtained using acetone as solvent for copolymers with ϕPCL = 0.50–0.58. These results emphasize, therefore, that control over the shape of PEO‐b‐PCL micelles can be achieved not only by precise macromolecular engineering but also through clever processing strategies.
Molecular Orientation and Morphology of Organized Molecular Films for Fluorinated Comb Copolymers
Authors: Fujimori Atsuhiro , Kobayashi Satoshi , Masuya Ryosuke , Masuko Toru , Ito Eisuke , Hara Masahiko , Kanai Kaname , Ouchi Yukio , Seki Kazuhiko , Nakahara Hiroo 
Published: February 2007

AbstractSurface morphology of monolayers related to solid‐state structure for methacrylate comb copolymers having fluorocarbon and hydrocarbon side‐chains was investigated by X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and atomic force microscopy (AFM). From the XRD profiles, two kinds of short spacing peaks were confirmed at 5.0 and 4.2 Å, which assigned the sub‐cells for both side‐chains. Furthermore, two kinds of endothermic peaks, which corresponded to melting peaks of the both side‐chain crystals, appeared in the thermograms. From the AFM observation, it was found that there were hydrogenated domains at a few hundred nm diameter in their monolayers, whereas corresponding acrylate copolymer monolayers form the phase‐separated structure at 10–30 nm order scales.
Catalysis of an Alkaline Hydrolysis Reaction by Ionenes Immobilized on Silica
Authors: Munhóz Maria Fernanda , Quina Frank H. 
Published: February 2007

AbstractIn this work, a novel approach for the covalent coupling of ionene polyelectrolytes to chloropropyl silica surfaces is described. The immobilized ionenes catalyze the alkaline hydrolysis of N‐dodecyl‐4‐cyanopyridinium (DCP) bromide, suggesting that, like the [3,22]‐ionene in solution, these immobilized ionenes are also capable of forming micelle‐mimetic microdomains.
Composition, Size Distribution and Characteristics of Aphron Dispersions
Authors: Spinelli Luciana , Bezerra Amanda , Aquino Aline , Lucas Elizabete , Monteiro Vitor , Lomba Rosana , Michel Ricardo 
Published: February 2007

AbstractThis work evaluates the composition, bubble size distribution and properties of aphron dispersions. The aphrons were prepared using two types of surfactants and three different continuous phases: distillated water, brine and ester. Xanthan gum and organophilic clay were used as viscosifiers and hydroxipropilated starch as a stabilizer. The dispersions were digitally imaged under an optical microscope at 60× magnification. These images were used to determine the size distribution. Phase separation was observed in ester‐based aphrons, and the phase separation progress was followed by image analysis. The percentage of incorporated air was determined by image analysis and by air compressibility. Aphrons produced from distillated water presented more bubbles and a smaller average diameter than those produced from brine or ester. Ester‐based aphrons incorporated a smaller percentage of air.
The Osmotic Behavior of Short Stiff Polyelectrolytes
Authors: Antypov Dmytro , Holm Christian 
Published: February 2007

AbstractWe report our recent advances in understanding when a simple cell model of a single, short polyelectrolyte is able to correctly reproduce the osmotic coefficient of a bulk solution. To this end we proposed a self‐consistent geometry optimized cell model. In contrast to the usual monotonic Poisson‐Boltzmann prediction, the cell model predicts the correct non‐monotonic dependence of the osmotic coefficient on concentration. A lower degree of polymerization is found to reduce significantly the counterion condensation for a typical dilute strong polyelectrolyte solution, thus increasing the osmotic coefficient. The results agree quantitatively with simulations of a corresponding many‐body bulk system up to a dense semi‐dilute regime. We investigate the effect of chain flexibility and on residual salt on the osmotic properties, and give a short overview about other effects which might be responsible for the observed discrepancy to recent experimental results on a PPP polyelectrolyte system.
Morphology and Microchemistry of Colloidal Polymers
Authors: Galembeck Fernando , Valadares Leonardo , Bragança Fábio do Carmo , Gouveia Rubia F. , da Silva Maria do Carmo V. M. 
Published: February 2007

AbstractColloidal polymers are highly versatile due to the variety of properties and functions that can be created by changing monomer composition, surfactant, initiator and reaction protocol. Microchemical and morphological observation of the particles and particle aggregates as well as films and monoliths made with them is allowing us to understand the connections between nanosized structural features and macroscopic properties and this is essential for the creation of valuable new polymer materials. Electron spectroscopy imaging (ESI) in the transmission electron microscope (TEM) uses electron energy loss spectroscopy (EELS) to provide a wealth of information on particle constituents and their topological distribution, allowing a number of correlations with the polymer mechanical, thermal, optical and electrical properties. On the other hand, scanning probe microscopy (SPM) techniques allow direct measurement of particle and film properties such as adhesion, stiffness, electrostatic potential as well as rheology information with high spatial resolution, down to 10‐20 nm and under many different experimental conditions. Information from the joint use of these techniques is revealing a wealth of nanostructures within colloidal polymers requiring a revision of many preconceived ideas on these materials.
Influence of Bentonite Type in Waterborne Polyurethane Nanocomposite Mechanical Properties
Authors: Ayres Eliane , Oréfice Rodrigo L. , Sousa Denise 
Published: February 2007

AbstractAbstract: Aqueous dispersion of polyurethane ionomer (PUD), based on poly (propylene glycol) (PPG) as soft segment, isophorone diisocyanate (IPDI) as diisocyanate, dimethylol propionic acid (DMPA) as ionic center, hydrazine (HZ) as crosslinker and triethyl amine (TEA) as neutralizer, was reinforced with 1 to 5 wt % of clay to obtain nanocomposites. Substitution of Na+‐montmorillonite for bentonite was made by using three types of bentonite. The tensile strength and elongation at break decreased for all nanocomposites having 5% clay in comparison to pristine polyurethane. The enhancement of mechanical properties over pristine polyurethane was achieved only by using 1% of clay. The structure of layered silicates in polyurethane was found to be maintained in some extent as evidenced from wide‐angle X‐ray diffraction analysis. Nevertheless, the rather weak and broad diffraction peaks appearing in the curves of bentonite clays nanocomposites indicated that a nanostructure of silicate in waterborne PU system has been formed using a low cost raw material and an environmental friendly aqueous polymer precursor.
Effect of Foster Swelling Degree in Polystyrene/Clay Nanocomposites Obtained by In Situ Incorporation
Authors: Arioli Rafael , Gonçalves Odinei H. , Castellares Lizabeth G. , da Costa João Manoel , Araújo Pedro H. , Machado Ricardo , Bolzan Ariovaldo 
Published: February 2007

AbstractDuring the in‐situ incorporation of an organophilic clay into the polymer matrix in a free radical polymerization, the radical should penetrate the basal space between the layers of the clay increasing the distance between these layers and leading to a nanocomposite with an intercalated or exfoliated morphology. The final morphology depends on the affinity of the monomer for the cation used to change the organophilicity of the clay. In this work, Foster swelling is applied as a method to obtain a degree of affinity of the clay for the monomer. The objective of this work is to study the effect of the Foster swelling degree on the final polystyrene/clay composite obtained by free‐radical polymerization of styrene containing organophilic clay. Some commercial organophilic clays with different Foster swelling degree were employed and the incorporation of the clays into polymer was carried out in bulk styrene polymerization reactions. The X‐ray diffraction (XRD) reveals the basal spacing of the clays before and after in‐situ incorporation indicating the morphology of the nanocomposite. The nanocomposites were also characterized by thermal gravimetric analysis (TGA). Results showed a correlation between Foster swelling degree and the morphology obtained. High values of Foster swelling degree lead to exfoliated polystyrene/clay nanocomposites, whereas decreasing this value intercalated, partially intercalated and only dispersed composites were obtained depending on the degree of affinity of the monomer for the clay.
Magnetite/Polymer Composite Particles Prepared by Molecular Assembling Followed by In‐Situ Magnetite Formation
Authors: Yamagata Mika , Abe Masanori , Handa Hiroshi , Kawaguchi Haruma 
Published: February 2007

AbstractMagnetic nano‐particles composed of superparamagnetic iron oxide in the core and hydrophilic polymer in the shell were prepared for the use of MRI contrast agents. Ferric and ferrous ions were added to an aqueous solution of block copolymer, poly(ethylene oxide)‐block‐poly(glycelol methacrylate‐co‐acrylic acid), which was prepared by living radical polymerization using iniferter. After iron ions‐polymer complex formation, the pH of the solution was raised to 11 to get magnetite nanoparticles which were encapsulated with polymer. Use of the polymer having the molecular weight of ca. 10,000 and the 100 × AAc/GLM of 1–10 and incubation of the mixture of iron ions and water‐soluble polymers at a moderate temperature resulted in the formation of favorable composite particles of 10–20 nm in diameter. The saturation magnetization and other instrumental analysis of composite particles suggested that the iron oxide formed in the above‐mentioned procedure was magnetite.
The Use of Suzuki Reaction to Form a New Electroluminescent Block Copolymer
Authors: Péres Laura Oliveira , Errien Nicolas , Froyer Gerard , Wang Shu Hui 
Published: February 2007

AbstractA new material from 4,4′‐dibromo‐p‐quaterphenyl (PPP oligomer) and 9,9‐dioctylfluorene‐2,7‐diboronic acid was easily synthesized by Suzuki reaction in good yield (84%). A complete characterization was done in order to compare the properties of the copolymer with its monomers. The material was readily soluble in organic solvents. The absorption as well as emission spectra presented red shifted compared to those from depart materials.
Electroluminescence of Phenothiazine‐Labeled Dendrimer Encapsulated 2‐{2‐[2‐(4‐Dimethylamino‐phenyl)‐vinyl]‐6‐methyl‐pyran‐4‐ylidene}‐Malononitrile Derivative: Effect of the Density of Phenothiazine Dendron
Authors: Kim Go Woon , Cho Min Ju , Jin Jung‐Il , Choi Dong Hoon , Paek Sang Hyon 
Published: February 2007

AbstractRed light emitting dendrimer (3) was synthesized by reacting 2‐[2,6‐bis‐(2‐{4‐[bis‐(6‐hydroxy‐hexyl)‐amino]‐phenyl}‐vinyl)‐pyran‐4‐ylidene]‐malononitrile (2) with 3,5‐bis‐{3,5‐bis‐[2‐(10‐hexyl‐10H‐phenothiazin‐3‐yl)‐vinyl]‐benzyloxy}‐ benzoic acid (1). The red emitting core dye capable of electronic excitation via Förster energy transfer was encapsulated by phenothiazine (PTZ) dendrons. The multi‐layered devices showed a luminance of 210 cd/m2 at 321 mA/cm2 (11.7 V) for the dendrimer only and 295 cd/m2 at 246 mA/cm2 (11.4 V) for the dendrimer with 3 wt% of PTZ dendron. The EL quantum efficiency (ηext = 0.79%) increased after doping an additional amount of PTZ dendron into the dendrimer.