bluuebunny/crossref_metadata_2025_split huggingface dataset:
1,3‐Dipolar Cycloaddition Reactions Initiated with the 1,5‐Dimethyl‐3‐phenyl‐6‐oxoverdazyl Radical
Authors: Yang Angela , Kasahara Takahito , Chen Eric K. Y. , Hamer Gordon K. , Georges Michael K. 
Published: August 2008

AbstractThe 1,5‐dimethyl‐3‐phenyl‐6‐oxoverdazyl radical reacts at room temperature in the presence of styrene to give a dihydrotetrazinone heterocyclic structure. We surmise that the reaction occurs by a 1,3‐dipolar cycloaddition via the intermediacy of an azomethine imine. While initial reactions under nitrogen gave relatively poor yields (40 %) of the cycloaddition product, improved yields (up to 84 %) were realized when the reaction mixtures were saturated with oxygen. Acrylate, methacrylate, fumarate and maleate dipolarophiles react regioselectively and stereospecifically to provide a series of dihydrotetrazinone heterocyclic structures. These initial results demonstrate the feasibility of using verdazyl radicals as substrates for organic synthesis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Covalent coating of hydroxyapatite by keratin stabilizes gentamicin release
Authors: Belcarz Anna , Ginalska Grażyna , Zalewska Justyna , Rzeski Wojciech , Ślósarczyk Anna , Kowalczuk Dorota , Godlewski Piotr , Niedźwiadek Justyna 
Published: August 2008

AbstractA novel hybrid hydroxyapatite (HAP) matrix, covalently coated with rarely applied, hardly degradable keratin and effectively modified by gentamicin immobilized in mixed‐type mode (via interactions of diverse strength), was created. This hybrid showed a remarkably high drug immobilization yield and the most sustainable antibiotic release among all tested composites. It was also able to inhibit bacterial growth, both in surrounding liquid and on matrix surface, much longer (for at least 121 days of experiment) than analogous gelatin‐modified and nonmodified matrices. Gentamicin‐keratin‐coated‐HAP granules were nontoxic to human osteoblasts and enabled their proliferation with a rate similar as noncoated HAP. Presence of keratin on HAP granules seemed to slightly enhance the osteoblast proliferation. The results indicate that newly created HAP hybrid with covalently immobilized keratin and gentamicin—nontoxic and osteoblast‐friendly—is a promising biomaterial of significantly prolonged antibacterial activity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Morphometric characteristics and reproductive capacity of nuclear transplants derived from embryonic cells of loach, Misgurnus anguillicaudatus
Authors: Tanaka Daisuke , Takahashi Akito , Ueno Kouichi 
Published: August 2008

AbstractNuclear transplants of loach were produced by transplantating blastula cell nuclei into nonenucleated unfertilized eggs, using recipient eggs and donor cells distinguished by different polymorphic microsatellites. Of the total of 2,847 operated eggs, 143 hatched and 119 developed to the feeding larval stage. For 15 nuclear transplants (i.e., 11.1‐year‐old fish and 4.2‐year‐old fish) that survived up to the adulthood, DNA analysis and karyotype analysis were performed. Results showed that, of the 15 fish, 14 had only a nucleus derived from the donor; moreover, 12 were diploids, 1 was a triploid, 1 was a tetraploid, and 1 was a diploid–tetraploid mosaic with both donor and recipient nuclei. For the 12 fish with only a 2n donor nucleus, morphometric analysis was performed, and two female fish and two male fish were mated with normal fish. The fish with only a 2n donor nucleus were determined to be morphometrically identical to normal fish: they had normal gametogenesis and were able to reproduce. Currently, nuclear transplantation technology is beginning to be adopted in fisheries. Biological information on nuclear transplants obtained in this study can be used in the development of nuclear transplantation technology. J. Exp. Zool. 311A:11–19, 2009. © 2008 Wiley‐Liss, Inc.
Kinetic‐energy‐sensitive mass spectrometry for separation of different ions with the same m/z value
Authors: Shiki Shigetomo , Ukibe Masahiro , Sato Yuki , Tomita Shigeo , Hayakawa Shigeo , Ohkubo Masataka 
Published: August 2008

AbstractA double‐focusing mass spectrometer (MS) equipped with a superconducting‐tunnel‐junction (STJ) detector has been applied to measure relative ionization cross‐sections for the production of ions that are accompanied by different ion species with the same mass‐to‐charge (m/z) value. The STJ detector fabricated for this study enables kinetic energy (E) measurement of incoming individual ions at a counting rate of up to ∼100 k ions/s and an energy resolution (ΔE/E) of 15%. Both high counting rate and high‐energy resolution are necessary to independently determine both m and z and not the m/z value only in ion‐counting MS experiments. Ions such as 14N22+ and 14N+ with the same m/z value can be clearly discriminated using a kinetic‐energy‐sensitive MS. This fine discrimination capability allows direct determination of relative ionization cross‐sections of the homonuclear diatomic ions 14N22+/14N2+ and 16O22+/16O2+, which are difficult to measure due to the strong interference by the signals of their dissociated atomic ions with noticeably large ionization cross‐sections. The new instrument requires no low‐abundance heteronuclear diatomic molecules of the forms 14N15N or 16O17O to carry out ionization studies and thus, is expected to be useful in fields such as atmospheric science, interstellar science, or plasma physics. Copyright © 2008 John Wiley & Sons, Ltd.
How retirees work: predictors of different types of bridge employment
Authors: Gobeski Kirsten T. , Beehr Terry A. 
Published: August 2008

AbstractEmployment after retirement, known as bridge employment, is expected to occur more frequently because the baby boom generation will increase the number of retirees. Little is known about which employees will obtain which type of bridge employment when they retire, even though it has important implications. The present study examined work‐related attitudes, job characteristics, and work‐related accomplishments of 171 retirees in order to predict whether they would fully retire or take one of two types of bridge jobs after retirement: Career‐consistent bridge jobs or bridge jobs in fields different from their original career. Continuity theory of retirement helped predict post‐retirement employment type. Retirees who had skills specifically related to their career job were more likely to work in a career‐related bridge job than either to fully retire or to take a bridge job that was not related to their careers; retirees who formerly held career jobs with intrinsically motivating job characteristics were more likely to take a career‐related bridge job than to retire fully, and retirees who had experienced work strain in their career job were more likely to take a bridge job not related to their former career than to take a career bridge job. Copyright © 2008 John Wiley & Sons, Ltd.
Inorganic reactions of iodine(III) in acidic solutions and free energy of iodous acid formation
Authors: Schmitz Guy 
Published: August 2008

AbstractAn analysis of the former works devoted to the reactions of I(III) in acidic nonbuffered solutions gives new thermodynamic and kinetic information. At low iodide concentrations, the rate law of the reaction IO + I− + 2H+ ⇌ IO2H + IOH is k+B [IO][I−][H+]2 – k−B [IO2H][IOH] with k+B = 4.5 × 103 M−3s−1 and k−B = 240 M−1s−1 at 25°C and zero ionic strength. The rate law of the reaction IO2H + I− + H+ ⇌ 2IOH is k+C [IO2H][I−][H+] – k−C [IOH]2 with k+C = 1.9 × 1010 M−2s−1 and k−C = 25 M−1s−1. These values lead to a Gibbs free energy of IO2H formation of −95 kJ mol−1. The pKa of iodous acid should be about 6, leading to a Gibbs free energy of IO formation of about −61 kJ mol−1. Estimations of the four rate constants at 50°C give, respectively, 1.2 × 104 M−3s−1, 590 M−1s−1, 2 × 109 M−2s−1, and 20 M−1 s−1. Mechanisms of these reactions involving the protonation IO2H + H+ ⇌ IO2H and an explanation of the decrease of the last two rate constants when the temperature increases, are proposed. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 647–652, 2008
Kinetic study of 2‐furanaldehyde, 3‐furanaldehyde, and 5‐methyl‐2‐furanaldehyde reactions initiated by Cl atoms
Authors: Cabañas B. , Tapia A. , Villanueva F. , Salgado S. , Monedero E. , Martín P. 
Published: August 2008

AbstractRate coefficients for the gas‐phase reactions of chlorine atoms with a series of furanaldehydes have been determined at 298 ± 2 K and atmospheric pressure (708.5 ± 0.1). The experiments were performed using the relative technique combined with solid‐phase microextraction (SPME) sampling and gas chromatography with flame ionization detection (GC‐FID). Rate constants were determined relative to the reaction of Cl withn‐nonane and 2‐ethylfuran. The absolute rate coefficientsk(in units of 10−10cm3molecule−1s−1) obtained were 2.61 ± 0.27 for 2‐furaldehyde, 3.15 ± 0.27 for 3‐furaldehyde, and 4 ± 0.5 for 5‐methyl‐2‐furaldehyde. This study shows that the reactions of furanaldehydes and Cl are very fast with little influence of the position of the aldehyde group or the presence of other substituent on the reactivity. The results seem to indicate a mechanism involving two main reaction channels, addition of chlorine atom to the double bond of the aromatic ring, and the abstraction of the aldehydic hydrogen. Further product studies are necessary to determine the mechanism of these reactions in more detail. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 670–678, 2008
Cure kinetics FTIR study of epoxy/nickel–imidazole system
Authors: Omrani A. , Simon L. C. , Rostami A. A. , Ghaemy M. 
Published: August 2008

AbstractIn the first part of this work (Omrani et al., Thermochim Acta 2008, 468, 39–48), we have reported mechanism and curing behavior of diglycidyl ether of bisphenol A (DGEBA) cured with a nickel salt of imidazole. In the present study, the isothermal cure of DGEBA–Im6NiBr2 system was investigated by in situ FTIR spectroscopy. Different amounts of nickel salt were loaded into epoxy matrix to elucidate the effects of the nickel catalyst concentration on the cure kinetics and mechanism. First‐order kinetic analysis was applied to estimate the rate constants for the both steps, adduct formation and chain‐growth polymerization, in the mechanism. It has been concluded that at high nickel salts concentrations, the studied cure reaction behaves like free‐imidazole‐epoxy cure. Analysis of the activation energy showed that the second step in the mechanism is more sensitive to the level of nickel salt than the first one. Using transition state theory, the thermodynamic functions of activated complex were also estimated. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 663–669, 2008
Thermal decomposition rate of N2O5 measured by cavity ring‐down spectroscopy
Authors: Ide Tomoyuki , Nakayama Tomoki , Takahashi Kenshi , Matsumi Yutaka 
Published: August 2008

AbstractThe thermal decomposition rate of N2O5 in 760 Torr of air as a function of temperature between 314 and 348 K has been investigated using the technique of pulsed laser cavity ring‐down spectroscopy (CRDS) detection of NO3 radicals at 662 nm. The Arrhenius expression of the thermal decomposition rates determined by the CRDS experiments, which is incorporated with literature values down to 263 K, is given by 1.36 × 1015 exp{(−11300 ± 200)/T} s−1 over the temperature range 263–348 K. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 679–684, 2008
Uptake Mechanism of Oppositely Charged Fluorescent Nanoparticles in HeLa Cells
Authors: Dausend Julia , Musyanovych Anna , Dass Martin , Walther Paul , Schrezenmeier Hubert , Landfester Katharina , Mailänder Volker 
Published: August 2008

AbstractThe endocytotic mechanisms involved in the uptake of charged polystyrene nanoparticles into HeLa cells were investigated. Uptake experiments were done in the presence or absence of drugs known to inhibit various factors in endocytosis. Independent of the particle charge, endocytosis is highly dependent on dynamin, F‐actin, and tyrosine‐specific protein kinases, which suggests a dynamin‐dependent and lipid raft‐dependent mechanism. However, cholesterol depletion did not hinder particle uptake. Regarding positively charged particles, macropinocytosis, the microtubule network, and cyclooxygenases are also involved. The clathrin‐dependent pathway plays a minor role.magnified image
Pseudo‐Living Anionic Telomerization of Buta‐1,3‐diene
Authors: Saito Tomonori , Harich Kim C. , Long Timothy E. 
Published: August 2008

AbstractLow‐molecular‐weight liquid polybutadienes (1 000–2 000 g · mol−1) consisting of 60 mol‐% poly(buta‐1,2‐diene) repeating units were synthesized via anionic telomerization. Maintaining the initiation and reaction temperature at less than 70 °C minimized chain transfer and enabled the polymerization to occur in a living fashion, which resulted in well‐controlled molecular weights and narrow polydispersity indices. MALDI‐TOF mass spectrometry confirmed that the end groups of liquid polybutadienes synthesized via anionic telomerization contained one benzyl end and one protonated end. In comparison, the end groups of liquid polybutadienes synthesized via living anionic polymerization contained one sec‐butyl or butyl end and one protonated end.magnified image
Microwave Promoted Polymer Analogous Amidation and Esterification of Poly(ether sulfone) Bearing Free Carboxylic Groups
Authors: Bezdushna Ella , Ritter Helmut 
Published: August 2008

AbstractAn effective method for modification of poly(ether sulfone) (PES) containing free carboxylic groups through amidation and esterification reactions applying a microwave technique is reported in this study. PES was synthesised by the condensation reaction of 4,4‐bis(hydroxyphenyl)‐pentanoic acid and bis(4‐chlorophenyl)sulfone. Thereupon, PES was condensed with 4‐aminobenzoic acid and 1‐naphthole under microwave irradiation and, as a comparison, under classical conditions in a pre‐heated oil bath. In contrast to the classical procedure, using microwaves, the polymer analogous amidation could be efficiently realised in apolar solvents. Incorporation of bulky aromatic groups into the polymer structure caused an increased shear rate dependent viscosity compared to the parent polymer.magnified image
New terpenoids from Stachys parviflora Benth
Authors: Ahmad Viqar Uddin , Arshad Saima , Bader Sadia , Iqbal Shazia , Khan Afsar , Khan Saleha Suleman , Hussain Javid , Tareen Rasool Bakhsh , Ahmed Amir 
Published: August 2008

AbstractTwo new triterpenoidal saponins were isolated from the n‐butanolic extract of Stachys parviflora (Lamiaceae). Their structures were elucidated on the basis of spectral data as stachyssaponin A; 3β, 15α, 19α, 21β, 22α‐pentahydroxyolean‐12‐ene‐28‐oic acid 3‐O‐{α‐L‐rhamnopyranosyl‐(1 → 3)‐β‐D‐glucopyranoside}‐22‐O‐{α‐L‐arabinofuranosyl‐(1 → 3)‐β‐D‐glucopyranoside} (1) and stachyssaponin B; 2β, 3β, 15α, 21β‐tetrahydroxyolean‐12‐ene‐28‐oic acid 2‐O‐[α‐L‐arabinofuranoside]‐3, 21‐bis‐O‐[β‐D‐glucopyranoside] (2). Copyright © 2008 John Wiley & Sons, Ltd.
Pulmonary function studies in children treated by chemoradiotherapy and stem cell transplantation
Authors: Efrati Ori , Toren Amos , Duskin Hadar , Modan‐Moses Dalit , Bielorai Bella , Goldstein Gal , Churi Chaim , Vilozni Daphna 
Published: August 2008

AbstractBackgroundManagement of pediatric patients with malignant and hematological diseases is frequently associated with pulmonary complications. We assessed pulmonary function at diagnosis and during a 5‐year follow‐up to identify risk factors associated with pulmonary deterioration.ProcedureNinety patients (age range 3–20) who were treated at the Pediatric Hematology‐Oncology Department, Sheba Medical Center, Israel, were entered into the study. Pulmonary function testing was performed at diagnosis and at least twice during the study period.ResultsAt diagnosis and thereafter values of spirometry, total lung capacity, functional residual capacity and diffusion capacity were significantly lower than predicted (P < 0.002 for all indices). The ratio between residual volume and total lung capacity (RV/TLC) was significantly higher than normal at diagnosis and throughout the study (P < 0.001). Age and treatment modalities did not show any effect on lung‐function during the study. A subgroup of seven patients (8%) developed Bronchiolitis obliterans (BO) after stem cell transplantation and development of graft versus host disease (GVHD). These patients' baseline FEF25–75 values (small airway disease) were significantly lower than FEF25–75 values of controls and other patients while all other parameters were similar. The RV/TLC in the BO patients gradually increased relative to other patients during the 5‐year follow‐up.ConclusionLung‐function in pediatric hemato‐oncological patients at diagnosis is lower than predicted. Abnormal baseline FEF25–75 may be a risk factor for the development of BO in the setting of GVHD after treatment. Careful monitoring, especially of FEF25–75 and RV/TLC at baseline and in the first period after diagnosis. Pediatr Blood Cancer 2008;51:684–688. © 2008 Wiley‐Liss, Inc.
Oligopeptide‐based amide functional initiators for ATRP
Authors: Adams Dave J. , Young Iain 
Published: August 2008

AbstractPolymer–peptide conjugates are receiving significant interest. Here, we show that, under the appropriate conditions, a small family of oligopeptide‐based initiators can be used successfully to initiate the polymerization of methacrylic monomers by atom transfer radical polymerization (ATRP), generating new examples of such materials. However, the use of the peptidic amide‐based initiators results in polymers which have a higher molecular weight than expected and a significantly higher polydispersity than those prepared from ester‐based initiators. In many cases significant initiator remains, suggesting that either not all peptides successfully initiate polymerization or that significant termination reactions occur early in the reaction. This low initiator efficiency agrees with other reports for amino acid‐based initiators. It therefore appears that such amide‐based initiators can be used successfully, but have a significantly lower applicability than the more commonly used ester‐based initiators. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6082–6090, 2008
Living cationic polymerization of amide‐functional vinyl ethers: Specific properties of SnCl4‐based initiating system
Authors: Yonezumi Motomasa , Okumoto Satoshi , Kanaoka Shokyoku , Aoshima Sadahito 
Published: August 2008

AbstractLiving cationic copolymerization of amide‐functional vinyl ethers with isobutyl vinyl ether (IBVE) was achieved using SnCl4 in the presence of ethyl acetate at 0 °C: the number–average molecular weight of the obtained polymers increased in direct proportion to the monomer conversion with relatively low polydispersity, and the amide‐functional monomer units were introduced almost quantitatively. To optimize the reaction conditions, cationic polymerization of IBVE in the presence of amide compounds, as a model reaction, was also examined using various Lewis acids in dichloromethane. The combination of SnCl4 and ethyl acetate induced living cationic polymerization of IBVE at 0 °C when an amide compound, whose nitrogen is adjacent to a phenyl group, was used. The versatile performance of SnCl4 especially for achieving living cationic polymerization of various polar functional monomers was demonstrated in this study as well as in our previous studies. Thus, the specific properties of the SnCl4 initiating system are discussed by comparing with the EtxAlCl3−x systems from viewpoints of hard and soft acids and bases principle and computational chemistry. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6129–6141, 2008
Synthesis and characterization of double thermo‐responsive block copolymer consisting N‐isopropylacrylamide by atom transfer radical polymerization
Authors: Kotsuchibashi Youhei , Kuboshima Yumi , Yamamoto Kazuya , Aoyagi Takao 
Published: August 2008

AbstractIn this thesis, we studied the convenient synthesis and characterizations of thermo‐responsive materials with double response. To achieve these, AB‐type diblock copolymers comprising of poly(N‐isopropylacrylamide) (NIPAAm) segment and poly(NIPAAm‐co‐(N‐(hydroxymethyl)acrylamide) (HMAAm)) one were designed. That was synthesized in one‐pot using an atom transfer radical polymerization (ATRP) technique. Poly(NIPAAm‐co‐HMAAm)s synthesized separately showed sensitive thermo‐response and the cloud point was completely tunable by the composition of HMAAm. As expected, the block copolymers exhibited double thermo‐responsive profiles in aqueous solution. The responsive behavior was discussed by precise trace by 1H NMR and turbidity measurements. From these results, we could confirm almost independent dehydration of each segment. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6142–6150, 2008
Preparation and characterization of porous polymeric microspheres obtained from multifunctional methacrylate monomers
Authors: Grochowicz Marta , Bartnicki Andrzej , Gawdzik Barbara 
Published: August 2008

AbstractSynthesis and properties of the new difunctional methacrylate monomer 2‐hydroxy‐3‐methacryloyloxypropoxybenzene are presented. This monomer was applied for the synthesis of porous microspheres. It was copolymerized with trimethylolpropane trimethacrylate in the presence of two pairs of pore‐forming diluents dodecane and toluene, and n‐decanol and toluene. Influence of diluents composition on their porous structures was studied. Thermal resistance and tendency to swell in different organic diluents for a chosen sample were also determined. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6165–6174, 2008
A novel dispersant for preparation of high loading and photosensitive carbon black dispersion
Authors: Kuo Kuo‐Huai , Peng Yu‐Hsiang , Chiu Wen‐Yen , Don Trong‐Ming 
Published: August 2008

AbstractHigh loading of stable carbon black (CB) dispersion in organic solvent, PGMEA, was prepared by a ball‐milling process when using poly(styrene‐EHA‐HEMA)‐block‐poly(styrene‐EHA‐HEMA‐DMAEMA) (P(SEH)‐b‐P(SEHD)) as a dispersant. The P(SEH)‐b‐P(SEHD) containing P(SEH) as a steric chain and P(SEHD) as an anchoring chain was prepared by TEMPO‐mediated polymerization. The tertiary amine group of DMAEMA in P(SEHD) chain could be adsorbed onto CB by the interaction with the carboxylic acid group on surface of CB and the P(SEH) chain could provide sufficiently steric repulsion force to avoid the aggregation of CB. In addition, a photosensitive dispersant, P(SEH)‐b‐P(SEHD)CC, containing the methacrylate double bond side group was also synthesized and was used to prepare stable CB dispersion in PGMEA. The effects of the molecular weight between steric and anchoring chains, the content of tertiary amine, and the amount of methacrylate double bond in the dispersant on the particle size of CB were investigated. Furthermore, the influences of various surface properties of CB, such as specific surface area, content of carboxylic acid group, and size of primary particle, on the particle size of CB in dispersion were also discussed. Finally, the photosensitivity of P(SEH)‐b‐P(SEHD)CC/CB composite was monitored by a photodifferential scanning calorimeter. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6185–6197, 2008