bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poloxamine hydrogels with a quaternary ammonium modification to improve cell attachment
Authors: Sosnik Alejandro , Sefton Michael V. 
Published: July 2005

AbstractFour‐arm poly(ethylene oxide) and poly(propylene oxide) (PEO‐PPO) block copolymer (poloxamine, Tetronic 1107™) hydrogels were modified with positively charged groups with the aim of overcoming the low cell adhesion properties of these PEO‐rich systems. Different matrices containing poloxamine‐methacrylate (6–12%) and a quaternary ammonium methacrylate ([2‐(methacryloyloxy)ethyl]‐trimethylammonium chloride [MAETAC], 0–0.48M) were produced by a photo‐initiated free radical copolymerization. A sharp increase in water content for MAETAC‐containing gels was seen during the first 2 days of incubation in distilled water; some of the gels showed water uptakes as high as 12 times the initial wet weight. In phosphate‐buffered saline (PBS), this effect was less pronounced because of the decrease in the osmotic gradient. In addition, a gradual increase of both the storage and the loss modulus of the gels resulted from increasing the MAETAC content [e.g., G′ values increased from 13,500 Pa for 12% poloxamine‐methacrylate gels without MAETAC to 151,000 Pa for 0.48M MAETAC contents (at 1 Hz, 100 Pa of oscillatory stress)]. Although on pure poloxamine‐methacrylate gels HepG2 and HUVEC cells attached poorly, on MAETAC‐containing specimens a well‐spread morphology and confluent monolayers were obtained, at least after preincubation in serum containing medium. Although not having all the cell compatibility of collagen, these fully synthetic quaternary ammonium‐modified PEO‐rich gels may have some utility in tissue‐engineering applications where stiff gels and cell attachment after gelation are desired. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Better osteoblast adhesion on nanoparticulate selenium— A promising orthopedic implant material
Authors: Perla Venu , Webster Thomas J. 
Published: July 2005

AbstractApart from problems such as poor osseointegration, stress shielding, and wear debris‐associated bone cell death, a major concern of metallic orthopedic implants is that they slowly corrode under in vivo environments. It is possible that continuous tissue exposure to metallic corrosion products limits orthopedic implant efficacy; this is especially true for patients receiving implants due to bone cancer. To date, there is no metallic orthopedic implant available in the market that specifically deals with the prevention and/or recurring cancer that may happen in these patients. The objective of this study was to deal with these problems in an integrated way by introducing a new biomaterial to the orthopedic community with anticancer chemistry: selenium (Se). In this study, six types of Se compacts were tested for bone cell (osteoblast) adhesion under in vitro conditions. Two types of cylindrical compacts were made with conventional Se metal particles in the micron (6.539 ± 1.364‐μm diameter) and submicron (0.963 ± 0.139‐μm diameter) range. These two types of compacts were chemically etched with different concentrations of NaOH to create two additional types of Se particles in each category: conventional size particles with nanosurface roughness and nanometer particles (0.204‐ to 0.264‐μm diameter). Results showed for the first time, enhanced osteoblast adhesion on particulate surfaces of the compacts made from conventional Se compared with reference nonparticulate wrought titanium sheets. More importantly, this study provided the first evidence that osteoblast density was further increased on the surfaces of the Se compacts with nanometer particles. These initial findings indicate that there may be a promising future for nanoparticulate Se as an anticancer biocompatible orthopedic material. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Utilization of spent petrochemical sulfuric acid in the production of wet‐process phosphoric acid
Authors: Chojnacki Andrzej , Chojnacka Katarzyna , Górecki Henryk 
Published: July 2005

AbstractThe possibility of the application of spent sulfuric acid from the petrochemical industry in wet‐process phosphoric acid technology was investigated. The effect of organic impurities in sulfuric acid from benzol acidic refining on the solubility of calcium sulfate hydrates is discussed. Solubility isotherms and regression equations for CaSO4–H3PO4–H2SO4–H2O (pure and containing impurities) systems are presented. Phase transition temperatures between dihydrate and hemihydrate calcium sulfate were determined. The difference between pure and polluted sulfuric acid systems observed is negligible over the range of typical wet‐process phosphoric acid technology parameters. It is concluded that the application of spent sulfuric acid from benzol acidic refining does not have a negative influence on the crystallization process of dihydrate calcium sulfate and therefore can be applied in wet‐process phosphoric acid technology. Copyright © 2005 Society of Chemical Industry
Removal characteristics of some priority organic pollutants from water in a fixed bed fly ash column
Authors: Sarkar Mitali , Acharya Pradip Kumar , Bhattacharya Bhaskar 
Published: July 2005

AbstractThe efficiency of a coal fly ash (generated from a thermal power plant) adsorption column for the removal of some priority organic pollutants, viz phenol, o‐hydroxyphenol, m‐hydroxyphenol and 4‐nitrophenol from aqueous solution has been studied. The column performance was evaluated from the concept of the formation of a primary adsorption zone and the breakthrough curve. The extent of solute removal obtained from breakthrough curve during column operation was compared with that obtained from the isotherm parameters for batch operation. The loaded solutes in the column were successfully eluted with acetone, achieving 98% recovery. In order to determine the practical applicability of the column operation the process was repeated a number of times and the variation of column capacity with number of operation cycles was evaluated. Even after six successive cycles, the column was found to retain almost 80% capacity. Copyright © 2005 Society of Chemical Industry
Microbial O‐demethylation of sinesetin and antimutagenic activity of the metabolite
Authors: Okuno Yoshiharu , Miyazawa Mitsuo 
Published: July 2005

AbstractBiotransformation of sinesetin by Aspergillus niger afforded 4′‐hydroxy‐5,6,7,3′‐tetramethoxyflavone on the basis of its spectroscopic data including IR, heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) analysis. Sinesetin and the metabolite showed antimutagenic activity against chemical mutagens 4‐dimethyl‐3H‐imidazo[4,5‐f]quinolin‐2‐amine (MeIQ) and 3‐amino‐14‐dimethyl‐5H‐pyrido[4,3‐b]indole (Trp‐P‐1) in the umu test using Salmonella typhimurium TA1535/pSK1002. Copyright © 2005 Society of Chemical Industry
Strong Fibers and Films of Microbial Polyesters
Authors: Iwata Tadahisa 
Published: July 2005

AbstractSummary: Poly[(R)‐3‐hydroxybutyrate] (P(3HB)) and its copolymers are accumulated by a wide variety of microorganisms as intracellular carbon and energy material, and are extensively studied as biodegradable and biocompatible thermoplastics. However, these microbial polyesters have not been recognized as practical because of their stiffness and brittleness. Recently, by new drawing techniques, we succeeded in obtaining strong fibers and films from microbial polyesters, produced by both wild‐type and recombinant bacteria. The improvement in mechanical properties of the fibers and films is due not only to the orientation of molecular chains, but also to the generation of a zigzag conformation and network structure, formed by fibrillar and lamellar crystals. The structure of strong fibers with a tensile strength over 1.0 GPa was analyzed by micro‐beam X‐ray diffraction with synchrotron radiation. The strong fibers and films were completely degraded in natural, river freshwater or by extracellular polyhydroxybutyrate depolymerases. In this feature article, the processing, mechanical properties, highly ordered structure and biodegradability of strong fibers and films produced from microbial polyesters are presented.
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Characterization of Carbon Monoxide Centered Triads in Poly[ethylene‐co‐(butyl acrylate)‐co‐(13C‐carbon monoxide)] by Isotopic Labeling and Two‐Dimensional NMR
Authors: Al‐Amri Abdullah , Monwar Masud , McCord Elizabeth F. , Buback Michael , Latz Henning , Rinaldi Peter L. 
Published: July 2005

AbstractSummary: Poly[ethylene‐co‐(butyl acrylate)‐co‐(carbon monoxide)] (polyEBC) samples, prepared from 13C‐labeled carbon monoxide, were characterized using two dimensional (2D) pulsed field gradient (PFG) 750 MHz NMR spectroscopy. To elucidate the complex mixture of structures present in this terpolymer, 2D 1H/13C‐heteronuclear multiple bond correlation (HMBC) experiments were conducted by selectively exciting the enhanced peaks resulting from 13C‐labeling. High resolution 2D NMR combined with 13C‐labeling of the polymer greatly simplifies the 2D NMR spectra, selectively enhances the weak peaks from low occurrence C‐centered triad structures and aids in their resonance assignments.
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On the Interpretation of X‐Ray Diffraction Powder Patterns in Terms of the Nanostructure of Cellulose I Fibres
Authors: Garvey Christopher J. , Parker Ian H. , Simon George P. 
Published: July 2005

AbstractSummary: The average lateral dimensions of cellulose microfibrils in paper sheets can be determined from the width of X‐ray Bragg peaks at half the maximum height. The method assumes it is the finite size of the crystallite which is the main contributor to peak broadening in the directions orthogonal to the long axis of the crystallite. This assumption is examined in the context of samples from different botanical sources, of varying crystallinity and cellulose content and the various instrumental sources of broadening X‐ray powder patterns. Excellent fits to the data from paper samples can be obtained by using five Voigt functions to the powder diffraction patterns, for the 101, $10\bar 1$, 021, 002 and 040 reflections. Of these reflections, the 020 is the clearest, and the best able to determine the lateral dimension of the crystallite. Results indicate that the size of microfibrils is dependent on the botanical source of the fibres.
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The Rapid Chain Extension of Anthracene‐Functional Polyesters by the Diels‐Alder Reaction with Bismaleimides
Authors: Kriegel Robert M. , Saliba Katie L. , Jones Genay , Schiraldi David A. , Collard David M. 
Published: July 2005

AbstractSummary: The chain extension of anthracene end‐capped oligoesters by reaction with bismaleimides constitutes a rapid route to high molecular weight polyesters. Polytransesterification of bis(2‐hydroxyethyl) terephthalate in the presence of a small amount of 2‐hydroxyethyl 2‐anthracenecarboxylate provides low molecular weight anthracene‐terminated macromers with anthracene end group functionality (fAN) of 1.66–1.85. These are subject to rapid chain extension with di(4‐maleimidophenyl)methane by Diels‐Alder cycloadditions resulting in consumption of the anthracene and maleimide end groups to generate polymers with $\overline M _{\rm n}$ > 2.0 × 104 g · mol−1. Thus, generation of the polymeric structure is achieved rapidly by addition reactions rather than sluggish transesterification reactions in which a condensate must be removed from the viscous polymer melt.Chain extension of low‐molecular weight 2‐anthracenecarboxylate terminated oligoesters.magnified imageChain extension of low‐molecular weight 2‐anthracenecarboxylate terminated oligoesters.
Synthesis and Optical Properties of Poly[2‐{N‐Methyl‐N‐(4‐(4‐ethynylphenylazo)phenyl)amino}ethyl butyrate]
Authors: Yin Shouchun , Xu Hongyao , Fang Min , Shi Wenfang , Gao Yachen , Song Yinlin 
Published: July 2005

AbstractSummary: The high‐molecular‐weight functional polyacetylene that contain a para‐aminoazobenzene chromophore, poly[2‐{N‐Methyl‐N‐(4‐(4‐ethynylphenylazo)phenyl)amino}ethyl butyrate] [poly(EAPAB)], was synthesized in moderate yield and characterized by FT‐IR, 1H NMR, UV‐vis, TGA, and GPC. The nonlinear optical and optical limiting properties were performed with 8 ns pulse width at 532 nm wavelength. The results show that the introduction of the flexible amino group effectively improved the solubility of polymer [poly(EAPAB)] in common organic solvent, such as CHCl3, THF, and dioxane, while poly(4‐ethynylazobenzene) [poly(4EAB)] without the flexible amino group shows poor solubility in common organic solvent. Simultaneously, poly(EAPAB) still shows good thermal stability, large third‐order nonlinear optical property, and novel optical limiting property owing to the functionalization of the para‐aminoazobenzene chromophore.Polymerization of EAPAB by Rh(nbd)Cl2‐Et3N to poly(EAPAB).magnified imagePolymerization of EAPAB by Rh(nbd)Cl2‐Et3N to poly(EAPAB).
Macrocyclic and Acyclic Bis(2,5‐diphenyl‐1,3,4‐oxadiazole)s with Electron‐Transporting and Hole‐Blocking Ability in Organic Electroluminescent Devices
Authors: Ono Katsuhiko , Ezaka Seiichi , Higashibata Akinori , Hosokawa Ryohei , Ohkita Masakazu , Saito Katsuhiro , Suto Michitaka , Tomura Masaaki , Matsushita Yosuke , Naka Shigeki , Okada Hiroyuki , Onnagawa Hiroyoshi 
Published: July 2005

AbstractSummary: Two types of bis(2,5‐diphenyl‐1,3,4‐oxadiazole)s, macrocyclic and acyclic, were prepared and evaluated as electron‐transporting and hole‐blocking materials in phosphorescent EL devices. Maximum efficiencies of ηext = 10.4% at J = 0.11 mA · cm−2 for the macrocycle and ηext = 14.1% at J = 3.01 mA · cm−2 for the acycle were observed. X‐ray crystallographic analysis and DSC measurements revealed a strong intermolecular interaction between the macrocycles and weaker intermolecular interactions between the acycles. The EL characteristics depend on the intermolecular interactions.The two types of bis(2,5‐diphenyl‐1,3,4‐oxadiazole)s used in the study.magnified imageThe two types of bis(2,5‐diphenyl‐1,3,4‐oxadiazole)s used in the study.
Complexation Behavior of Cu2+ in the Presence of Iminodiacetic Acid and Poly(ethyleneimine)
Authors: Moreno‐Villoslada Ignacio , González Felipe , Jofré Marlen , Chandía Patricio , Hess Susan , Rivas Bernabé L. 
Published: July 2005

AbstractSummary: Multicomponent aqueous systems containing Cu2+ as metal ion, iminodiacetic acid (IDAA) as a low‐molecular‐weight chelating molecule, and branched poly(ethyleneimine) (BPEI) as a polychelatogen are analyzed at different pH by UV‐Vis spectroscopy and diafiltration. It was found that at pH 4, saturation of BPEI with Cu2+ takes place at a Cu2+:BPEI ratio of 1:5.7, probably indicating a stoichiometry for the complex of 1:4. At the same conditions the Cu2+‐IDAA complex has a stoichiometry of 1:1. The ability of BPEI to bind the metal ion is higher than that of IDAA in mixtures of both chelating molecules. Lowering the pH between 2 and 3.5, protonation of BPEI allows increasing the amounts of Cu2+‐IDAA complex so that Cu2+ is transferred from the polychelatogen to IDAA. Good correlations are found comparing the results obtained by diafiltration and by UV‐Vis spectroscopy. Moreover, diafiltration results indicate that in the absence of Cu2+, IDAA interacts with BPEI with apparent dissociation constants of 2.88 at pH 2.7 and 0.96 at pH 4. These interactions may be responsible for the appearance of an apparent dissociation constant of 3.60 for the interactions between BPEI and the Cu2+‐IDAA complex at pH 4.The binding of Cu2+ to branched poly(ethyleneimine) and iminodiacetic acid in water.magnified imageThe binding of Cu2+ to branched poly(ethyleneimine) and iminodiacetic acid in water.
Sorption of Hydrophobic Organic Compounds by Aqueous Latexes
Authors: Tauer Klaus , Nozari Samira , Ali A. M. Imroz , Kozempel Steffen 
Published: July 2005

AbstractSummary: Optical absorption measurements are used for the first time to investigate the uptake of pure organic solvents or solutions by latex particles. Sorption into glassy polymer particles is a two‐stage process with distinctly different characteristic times, which reflects that an initial softening of the outer particle layer facilitates further uptake. The sorption of solutions containing highly water‐insoluble compounds allows the preparation of composite nanoparticles, which are hardly accessible by other routes.Photograph of the neat 100 nm latex (right) particles and the particles after dying by sorption with the hydrophobic pigment Sudan IV (left).magnified imagePhotograph of the neat 100 nm latex (right) particles and the particles after dying by sorption with the hydrophobic pigment Sudan IV (left).
Effect of Turbulent Flow on Coil‐Globule Transition of λ‐DNA
Authors: Lim Sung Taek , Choi Hyoung Jin , Chan Chi‐Keung 
Published: July 2005

AbstractSummary: The addition of spermidine (SPD) into turbulent flow as a condensing agent showed the abrupt change of turbulent drag reducing (DR) efficiency of λ‐DNA in turbulent flow for the first time. The resultant asymptote DR efficiency explains the origin of those changes, which can be conclusively verified via the electrophoresis experiment. Despite the different fluid conditions, with and without condensing agent, all λ‐DNA molecules possessed the same half‐cut dimension, implying that the discrete change of DNA conformation can dramatically alter the flow characteristics.Coil‐globule transition of DNA by spermidine.magnified imageCoil‐globule transition of DNA by spermidine.
Applications of accelerator mass spectrometry for pharmacological and toxicological research
Authors: Brown Karen , Tompkins Elaine M. , White Ian N.H. 
Published: July 2005

AbstractThe technique of accelerator mass spectrometry (AMS), known for radiocarbon dating of archeological specimens, has revolutionized high‐sensitivity isotope detection in pharmacology and toxicology by allowing the direct determination of the amount of isotope in a sample rather than measuring its decay. It can quantify many isotopes, including 26Al, 14C, 41Ca, and 3H with detection down to attomole (10−18) amounts. Pharmacokinetic data in humans have been achieved with ultra‐low levels of radiolabel. One of the most exciting biomedical applications of AMS with 14C‐labeled potential carcinogens is the detection of modified proteins or DNA in tissues. The relationship between low‐level exposure and covalent binding of genotoxic chemicals has been compared in rodents and humans. Such compounds include heterocyclic amines, benzene, and tamoxifen. Other applications range from measuring the absorption of 26Al to monitoring 41Ca turnover in bone. In epoxy‐embedded tissue sections, high‐resolution imaging of 14C label in cells is possible. The uses of AMS are becoming more widespread with the availability of instrumentation dedicated to the analysis of biomedical samples. © 2005 Wiley Periodicals, Inc.
A study of glycoproteins in human serum and plasma reference standards (HUPO) using multilectin affinity chromatography coupled with RPLC‐MS/MS
Authors: Yang Ziping , Hancock William S. , Chew Tori Richmond , Bonilla Leo 
Published: July 2005

AbstractThe glycoproteome is a major subproteome present in human plasma. In this study, we isolated and characterized approximately 150 glycoproteins from the human plasma and serum samples provided by HUPO using a multilectin affinity column. The corresponding tryptic digest was separated by RP‐HPLC coupled to an IT mass spectrometer (3‐D LCQ). Also in this study, a new system, namely an Ettan MDLC system coupled to a linear ITLTQ, was compared with the previous LCQ platform and gave a greater number of protein identifications, as well as better quality. When we compared the composition of the glycoproteomes for the plasma and serum samples there was a close correlation between the samples, except for the absence of fibrinogen from the identified‐protein list in the latter sample, which was presumably as a result of the clotting process. In addition, the analysis of the samples from three ethnic specimens, Caucasian American, Asian American, and African American, were very similar but showed a higher angiotensinogen plasma level and a lower histidine‐rich glycoprotein level in Caucasian American samples, and a lower vitronectin level in African American blood samples.
Differences among techniques for high‐abundant protein depletion
Authors: Zolotarjova Nina , Martosella James , Nicol Gordon , Bailey Jerome , Boyes Barry E. , Barrett William C. 
Published: July 2005

AbstractThe need to identify protein or peptide biomarkers via readily available biological samples like serum, plasma, or cerebrospinal fluid is often hindered by a few particular proteins present at relatively high concentrations. The ability to remove these proteins specifically, reproducibly, and with high selectivity is increasingly important in proteomic studies, and success in this procedure is leading to an ever‐increasing list of lower abundant proteins being identified in these biological fluids. The current work addresses some of the potential problems in depleting proteins in typical biomarker studies, including nonspecific binding during depletion procedures and whether low molecular weight (LMW) species bind to the column in a so‐called “sponge” effect caused by the ability of albumin or other high‐abundant proteins to bind peptides or protein fragments. LC‐MS/MS methods were applied to the comparative analysis of an IgG‐based immunodepletion method and a Cibacron blue (CB)‐dye‐based method, for specificity of removing targeted proteins (binding fraction), as well as for assessing efficiency of target removal. This analysis was extended to examine the effects of repeated use of materials (cycles of binding and elution), in order to assess potential for carryover of one sample to the next. Capacity studies and efficiency of protein removal from the serum samples were followed for the IgG‐based system using both immunochemical assays (ELISA) as well as LC‐MS/MS methods. Additionally, the IgG‐based system was further characterized for the removal of LMW polypeptides by nonspecific binding. We conclude that the IgG‐based system provided effective removal of targeted proteins, with minimal carryover, high longevity, and minimal nonspecific binding. Significant differences are noted between the depletion techniques employed, and this should be considered based on the expectations set during experimental design.
Synthesis of well‐defined aromatic polyesters by chain‐growth polycondensation under suppression of transesterification
Authors: Iwashita Ken‐ichi , Yokoyama Akihiro , Yokozawa Tsutomu 
Published: July 2005

AbstractFor the synthesis of aromatic polyesters with defined molecular weights and narrow molecular weight distributions (MWDs), we investigated the chain‐growth polycondensation of active amide derivatives of 4‐hydroxybenzoic acid, 1a and 1b, having an octyl or 4,7‐dioxaoctyl side chain, respectively. To suppress the transesterification of the polymer backbone with the monomer, the polymerization of 1 was carried out in tetrahydrofuran (THF) at −30 °C in the presence of initiator 2 and Et3SiH/CsF/18‐crown‐6, which generated a hydride ion as a base in situ. The number‐average molecular weight (Mn) of poly1a was controlled, and narrow MWDs were maintained, until the [1a]0/[2]0 feed ratio was 14.3 (Mn ≤ 3500), whereas that of poly1b was controlled until the feed ratio was 30 (Mn ≤ 7250). The difference stemmed from the higher solubility of poly1b in THF. This chain‐growth polycondensation was applied to the synthesis of a diblock copolyester of 1a and 1b of a defined architecture. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4109–4117, 2005