bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hyperbranched Acrylate Copolymer via Initiator‐Fragment Incorporation Radical Copolymerization of Divinylbenzene and Ethyl Acrylate: Synthesis, Characterization, Hydrolysis, Dye‐Solubilization, Ag Particle‐Stabilization, and Porous Film Formation
Authors: Sato Tsuneyuki , Nobutane Hiroki , Hirano Tomohiro , Seno Makiko 
Published: January 2006

AbstractSummary: Soluble hyperbranched acrylate copolymers were prepared by the copolymerization of divinylbenzene (0.10 mol · L−1) and ethyl acrylate (0.50 mol · L−1) using dimethyl 2,2′‐azoisobutyrate of high concentrations (0.30–0.50 mol · L−1) as initiator at 70 and 80 °C in benzene. The copolymer formed at 80 °C for 1 h showed the weight‐average molecular weight of 2.5 × 105, the small radius of gyration of 10 nm, the low second virial coefficient of 5.7 × l0−7 mL · g−2 as shown by the MALLS measurements at 25 °C in tetrahydrofuran, and also the very low intrinsic viscosity of 0.10 dL · g−1 at 30 °C in benzene. The hyperbranched copolymer exhibited an upper critical solution temperature (35 °C on cooling) in an acetone‐water (60:11 v/v). The copolymer showed an ability to encapsulate and transfer Rhodamine 6G as a dye probe and could stabilize Ag nanoparticles. The porous film was prepared by simply casting an acetone solution of the hyperbranched copolymer on a cover glass. The copolymer molecules radially arranged on the surface layer of the spherical pores as observed by the polarized optical microscope. The hyperbranched acrylate copolymer was hydrolyzed by KOH to yield poly(carboxylic acid).Optical microscope image (crossed polarizers) of a porous film from copolymer solution in acetone.imageOptical microscope image (crossed polarizers) of a porous film from copolymer solution in acetone.
New Functional Polyolefins: Towards a Bridge Between Catalytic and RAFT Polymerizations?
Authors: Godoy Lopez Ricardo , Boisson Christophe , D'Agosto Franck , Spitz Roger , Boisson Fernande , Gigmes Didier , Bertin Denis 
Published: January 2006

AbstractSummary: Di‐polyethylenyl magnesium compounds, obtained by a transition metal catalyzed chain growth reaction on butyloctyl magnesium, are reacted with a range of disulfides of thiocarbonylated compounds (RC(S)SSC(S)R). Xanthate, dithiocarbamate, dithioester, and trithiocarbonate‐functionalized polyethylenes are thus obtained and characterized by 1H NMR and IR spectroscopy, and MALDI TOF mass spectrometry. These macroRAFT agents may serve as building blocks for the synthesis of block copolymers based on polyolefins and polar segments.Thio thiocarbonylate‐terminated polyethylene chains are easily prepared in high yield by a two step reaction and analyzed by MALDI‐TOF mass spectrometry.magnified imageThio thiocarbonylate‐terminated polyethylene chains are easily prepared in high yield by a two step reaction and analyzed by MALDI‐TOF mass spectrometry.
Spontaneous Vesicle Formation in Aqueous Solutions of Comb‐Like PEG
Authors: Li Xiaolin , Ji Jian , Shen Jiacong 
Published: January 2006

AbstractSummary: A novel comb‐like poly(ethylene glycol) (CPEG), with dominant water‐soluble PEG, is found to spontaneously aggregate into vesicles above a certain concentration in water. The hollow, three‐dimensional structure of the vesicles is proven by TEM, SEM, and AFM. The diameters of the vesicles are from 200 to 500 nm with 50 nm walls. The spontaneously formed vesicles can be further cross‐linked by the reaction between divinyl sulfone (DVS) and the hydroxy groups in the side chains of the CPEG. The spontaneously formed vesicles with dense reactive hydroxy groups will have great potential in both applications and research.SEM image of the uncross‐linked vesicles.magnified imageSEM image of the uncross‐linked vesicles.
2‐Nitro‐1,4‐diaminobenzene‐Functionalized Poly(vinyl amine)s as Water‐Soluble UV‐Vis‐Sensitive pH Sensors
Authors: Roth Isabelle , Jbarah Abdel Aziz , Holze Rudolf , Friedrich Manfred , Spange Stefan 
Published: January 2006

AbstractSummary: Nucleophilic aromatic substitution of 2,6‐O‐dimethyl‐β‐cyclodextrin (β‐DMCD)‐complexed 4‐fluoro‐3‐nitroaniline derivatives with poly(vinyl amine) (PVAm) in water results in 2‐nitro‐1,4‐benzenediamine‐functionalized water‐soluble PVAms in one step. The 2‐nitro‐1,4‐benzenediamine moiety linked to the polymer is solvatochromic and undergoes protonation and deprotonation as function of pH as shown by UV‐Vis spectroscopy. The occurrence of an isosbestic point in the UV‐Vis spectrum is suitable to directly determine the pKa value using the Henderson‐Hasselbalch equation. The influence of the methyl group substitution of the polymer and the 2‐nitro‐1,4‐benzenediamine moiety on the pKa is discussed.Structure of the 4‐N,N‐dimethyl‐2‐nitro‐1,4‐benzenediamine‐functionalized PVAm and its solution in water at varying pH.magnified imageStructure of the 4‐N,N‐dimethyl‐2‐nitro‐1,4‐benzenediamine‐functionalized PVAm and its solution in water at varying pH.
On the solution of Maxwell's equations in polygonal domains
Authors: Nkemzi Boniface 
Published: January 2006

AbstractThis paper is concerned with the structure of the singular and regular parts of the solution of time‐harmonic Maxwell's equations in polygonal plane domains and their effective numerical treatment. The asymptotic behaviour of the solution near corner points of the domain is studied by means of discrete Fourier transformation and it is proved that the solution of the boundary value problem does not belong locally to H2 when the boundary of the domain has non‐acute angles. A splitting of the solution into a regular part belonging to the space H2, and an explicitly described singular part is presented. For the numerical treatment of the boundary value problem, we propose a finite element discretization which combines local mesh grading and the singular field methods and derive a priori error estimates that show optimal convergence as known for the classical finite element method for problems with regular solutions. Copyright © 2006 John Wiley & Sons, Ltd.
Bull testicular haploid germ cells express a messenger encoding for a truncated form of the protein tyrosine kinase HCK
Authors: Lalancette Claudia , Bordeleau Louis‐Jean , Faure Robert L. , Leclerc Pierre 
Published: January 2006

AbstractProtein tyrosine phosphorylation is a process that has been studied worldwide during sperm capacitation and acrosomal exocytosis events. Although few capacitation‐induced phosphotyrosine‐containing proteins have been identified, little is known about the tyrosine kinases directly involved in this post‐translational modification. Different studies from our and other groups using tyrosine kinase inhibitors suggest the involvement of members of the family of src‐related tyrosine kinases in the sperm capacitation associated increase in protein tyrosine phosphorylation. Using a molecular biology approach, we report for the first time messengers encoding for members from the src‐related tyrosine kinase family in bovine spermatogenic cells. Degenerated primers were designed within a highly homologous region specific to the family of src tyrosine kinases, and RNAs coding for c‐src, c‐yes, lyn, lck, and hck were identified in bull testis and haploid germ cells by RT‐PCR. We also report the presence of a messenger in haploid bull germ cells that could encode for a truncated isoform of the hck tyrosine kinase. This messenger was detected by screening of a haploid germ cells cDNA library using the RT‐PCR product homologous to hck as a probe. The presence of this transcript in haploid germ cell RNA preparations was validated by RT‐PCR, 3′RACE, 5′RACE as well as Northern blot. Such a truncated protein could function as an adaptor protein or as a competitive inhibitor in spermiogenesis or mature sperm functions. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Impedances of rigid cylindrical foundations embedded in transversely isotropic soils
Authors: Barros P. L. A. 
Published: January 2006

AbstractA complete formulation and implementation for assessment of the response to dynamic loads of cylindrical rigid structures embedded in transversely isotropic elastic half‐spaces is presented. The analysis is performed in the frequency domain and the steady‐state structure response is obtained. The method is based on a non‐singular version of the indirect boundary element method which uses influence functions, instead of Green's functions, as fundamental solutions. These influence functions are the response of an elastic half‐space to distributed, internally applied loads. The proposed method imposes full bonding contact between the foundation and the surrounding soil. Numerical results for displacement (vertical and horizontal) and rotation (twisting and rocking) impedances, showing the influence of the soil anisotropy, are presented. Results for the soil–structure interface tractions and for the displacement field throughout the half‐space are also shown. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation and characterisation of tractable regioregular head‐to‐tail poly(3‐alkylthiophene)s with ferrocene substituents
Authors: Iraqi Ahmed , Pickup David F 
Published: January 2006

AbstractThe preparation of a new ferrocene functionalised regioregular head‐to‐tail poly(3‐alkylthiophene) is presented. The polymer was obtained by post‐modification of a regioregular head‐to‐tail poly[3‐(6‐bromohexyl)thiophene] polymer and full functionalisation was achieved. The polymer is fully soluble in common organic solvents and was fully characterised by NMR, UV‐visible, photoluminescence spectroscopy and gel permeation chromatography. Cyclic voltammetry studies were also conducted on the polymer and revealed highly stable films under repeated cycling conditions up to 0.65 V (versus Ag/Ag+), with no attenuation of the electroactivity of films after several cycles. Copyright © 2006 Society of Chemical Industry
Database of two‐dimensional polyacrylamide gel electrophoresis of proteins labeled with CyDye DIGE Fluor saturation dye
Authors: Fujii Kazuyasu , Kondo Tadashi , Yokoo Hideki , Okano Tetsuya , Yamada Masayo , Yamada Tesshi , Iwatsuki Keiji , Hirohashi Setsuo 
Published: January 2006

AbstractCyDye DIGE Fluor saturation dye (saturation dye, GE Healthcare Amersham Biosciences) enables highly sensitive 2‐D PAGE. As the dye reacts with all reduced cysteine thiols, 2‐D PAGE can be performed with a lower amount of protein, compared with CyDye DIGE Fluor minimal dye (GE Healthcare Amersham Biosciences), the sensitivity of which is equivalent to that of silver staining. We constructed a 2‐D map of the saturation dye‐labeled proteins of a liver cancer cell line (HepG2) and identified by MS 92 proteins corresponding to 123 protein spots. Functional classification revealed that the identified proteins had chaperone, protein binding, nucleotide binding, metal ion binding, isomerase activity, and motor activity. The functional distribution and the cysteine contents of the proteins were similar to those in the most comprehensive 2‐D database of hepatoma cells (Seow et al.., Electrophoresis 2000, 21, 1787–1813), where silver staining was used for protein visualization. Hierarchical clustering on the basis of the quantitative expression profiles of the 123 characterized spots labeled with two charge‐ and mass‐matched saturation dyes (Cy3 and Cy5) discriminated between nine hepatocellular carcinoma cell lines and primary cultured hepatocytes from five individuals, suggesting the utility of saturation dye and our database for proteomic studies of liver cancer.
Two distinct heme distal site states define Cerebratulus lacteus mini‐hemoglobin oxygen affinity
Authors: Martí Marcelo A. , Bikiel Damían E. , Crespo Alejandro , Nardini Marco , Bolognesi Martino , Estrin Dario A. 
Published: January 2006

AbstractThe nerve tissue hemoglobin of Cerebratulus lacteus (CerHb) is the smallest naturally occurring known hemoglobin. Stabilization of the diatomic bound species (e.g., O2) is achieved through a network of hydrogen bonds based on three key residues TyrB10, GlnE7, and ThrE11. The first two residues are typically associated in hemoglobins with enhanced O2 affinity, related to hydrogen bond stabilization of the heme‐bound O2 resulting in a decrease of the ligand dissociation rates. In contrast to the above observations, the affinity of CerHb for O2 is only moderate, and the rate of O2 dissociation is unexpectedly high. To gain insight on the diverse molecular mechanisms controlling ligand affinities, we have analyzed w.t. CerHb and its ThrE11→Val mutant by means of joint molecular dynamics and quantum mechanics simulation techniques, complementing recent site‐directed mutagenesis experiments. Our results suggest that the observed O2 dissociation rates can only be explained through a dynamic equilibrium between high and low affinity states of the w.t. CerHb heme distal site. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Synthesis of tetrazole analogs of γ‐ and δ‐amino acids
Authors: Moutevelis‐Minakakis Panagiota , Filippakou Maria , Sinanoglou Charalambos , Kokotos George 
Published: January 2006

AbstractN‐benzyloxycarbonyl‐protected α‐ or β‐amino alcohols, easily prepared from α‐ and β‐amino acids, were converted into aldehydes and directly reacted with (triphenyl phosphoranylidene) acetonitrile, leading to unsaturated nitriles. Treatment of nitriles with NaN3 and ZnBr2 produced unsaturated γ‐ and δ‐amino tetrazoles, which were deprotected and converted to the corresponding saturated compounds by catalytic hydrogenation. For the case of δ‐amino tetrazole, the methylation of the acidic moiety occurred after treatment with CH2N2, leading to the N1‐ and N2‐methylated constitutional isomers, which were separated by column chromatography and hydrogenated. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Design of novel bicyclic analogues derived from a potent oxytocin antagonist
Authors: Flouret George , Chaloin Olivier , Borovickova Lenka , Slaninová Jirina 
Published: January 2006

AbstractEleven new analogues were synthesized by modification of the potent oxytocin antagonist (OTA) [(S)Pmp1, D‐Trp2, Pen6, Arg8]‐Oxytocin, or PA (parent antagonist), in which (S)Pmp = β,β‐(3‐thiapentamethylene)‐β‐mercapto‐propionic acid. By internal acylation of Lys, Orn, L‐1,4‐diaminobutyric acid (Dab), L‐1,3‐diaminopropionic acid (Dap) at position 4 with the C‐terminal Gly of the peptide tail, we prepared cyclo‐(4–9)‐[Lys4, Gly9]‐PA (pA2 = 8.77 ± 0.27), 1, and cyclo‐(4–9)‐[Orn4, Gly9]‐PA (pA2 = 8.81 ± 0.25), 3, which are equipotent with PA (pA2 = 8.68 ± 0.18) in the rat uterotonic assay and cyclo‐(4–9)‐[Dab4, Gly9]‐PA, 4, cyclo‐(4–9)‐[Dap4, Gly9]‐PA, 5, and cyclo‐(4–9)‐[Pmp1, Lys4, Gly9]‐PA, 2, which were weaker OTAs. Neither 1 nor 3 had activity as agonists or antagonists in the antidiuretic assay. In the pressor assay, both analogues 1 and 3, with pA2 = 7.05 ± 0.10 and pA2 = 6.77 ± 0.12, respectively, are somewhat weaker antagonists than PA (pA2 = 7.47 ± 0.35) showing significant gain in specificity. The [desamido9] PA‐ethylenediamine monoamide, 6, and the dimer ([desamido9]‐PA)2 ethylenediamine diamide, 7, had lower potency in the uterotonic assay than PA. Additionally, we synthesized cyclo‐(1–5)‐[(HN)Pmp1, Asp5]‐PA, 8, inactive in all tests, which suggests that the intact Asn5 side chain may be critical in the interaction of the OTAs with the oxytocin (OT) receptor. Similarly, cyclo‐(5–9)‐[Dap5, Gly9]‐PA, 9, had very low uterotonic potency. Two derivatives of PA truncated from the C‐terminus were internally cyclized to Lys4, giving rise to cyclo‐(4–8)‐desGly‐$\hbox{NH}_{2}^{9}$[Lys4, Arg8]‐PA, 10 (pA2 = 8.35 ± 0.20), which maintains the high potency of PA and has no activity in the rat antidiuretic assay, and in the rat pressor assay it is about ten times weaker (pA2 = 6.41 ± 0.15) than PA (pA2 = 7.47 ± 0.35), thus showing gains in specificity, and to cyclo‐(4–7)‐desArg‐Gly‐$\hbox{NH}_{2}^{8-9}$[Lys4, Pro7)‐PA, 11, which has much weaker potency than PA. Synthesis of cyclo‐(4–6)‐desPro‐Arg‐Gly‐$\hbox{NH}_{2}^{7-9}$[Lys4]‐PA failed. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Combining a polar resin and a pseudo‐proline to optimize the solid‐phase synthesis of a ‘difficult sequence’
Authors: Cremer Gaëlle‐Anne , Tariq Hanane , Delmas Agnes F. 
Published: January 2006

AbstractThis paper describes the optimization of a synthesis of a difficult sequence related to a 12‐mer sequence of a Pan DR epitope (PADRE). Elongation was followed by on‐line monitoring of the Nα‐Fmoc removal adapted for the batch methodology. Studying the intrinsic factors related to the peptide‐resin, such as substitution level, resin nature and backbone protecting group, has led to an increase in the elongation yield and purity of the crude peptide. Optimal elongation was obtained by combining a polar resin such as PEGA and a pseudo‐proline as the backbone protecting group. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
The one‐electron oxidation of [HCCOCC]− to form neutral HCCOCC, and the subsequent rearrangement of HCCOCC to form HCCCCO. An experimental and computational study
Authors: Fitzgerald Mark , Bowie John H. 
Published: January 2006

AbstractThe singlet anion [HCCOCC]− may be made in the source of a VG ZAB 2HF mass spectrometer by the reaction between F− (from SF6) and HCCOCCTMS. Vertical (Franck‐Condon) one‐electron oxidation of [HCCOCC]− in the first collision cell produces doublet neutral HCCOCC. A combination of experiment and molecular modelling [at the CCSD(T)/aug‐cc‐pVDZ//B3LYP/6–31 + G(d) level of theory] provides data which are consistent with some HCCOCC neutrals being stable for the duration of the neutralisation reionisation experiment, while others rearrange to form the decomposing doublet neutral HCCCCO. Copyright © 2006 John Wiley & Sons, Ltd.
Studies of gas‐phase fragmentation reactions of [Pd(PPh3)2(OCOR)]+ by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry
Authors: Qian Rong , Guo Hao , Liao Yuanxi , Wang Haoyang , Zhang Xiang , Guo Yinlong 
Published: January 2006

AbstractGas‐phase fragmentation reactions of [Pd(PPh3)2(OCOR)]+ (R = H, CH3, CD3, C2H5, n‐C3H7, n‐C6H13 and C6H5) were studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FTICRMS). In sustained off‐resonance irradiation collision‐activated dissociation (SORI‐CAD) experiments, the complexes all dissociated to yield the same product ion at m/z 629.1. We propose that the fragmentation pathway occurs through the elimination of RCOOH and a palladium(IV) hydride intermediate. Semi‐empirical (PM3) calculations shed light on the mechanism for the fragmentation reactions of these compounds. The results of deuterium‐labeling experiments indicate that the protons of RCOOH lost from [Pd(PPh3)2(OCR)]+ originate from the phenyl in the triphenylphosphine ligand. [Pd(PPh3)2(OCOH)]+ undergoes two competitive pathways in SORI‐CAD experiments, one of which is similar to that of [Pd(PPh3)2(OCOR)]+ (R = CH3, CD3, C2H5, n‐C3H7, n‐C6H13 and C6H5), and the other involves decarboxylation. The present study demonstrates that MS could play an important role in studying the gas‐phase chemistry of palladium hydrides. Copyright © 2006 John Wiley & Sons, Ltd.
Pharmacological characterization of endothelin receptors‐mediated contraction in the mouse isolated proximal and distal colon
Authors: Khan Humaira , Naylor Robert J , Tuladhar Bishwa R 
Published: January 2006

The study investigated the role of endothelin (ET) and the ET receptor subtypes ETA and ETB in mediating longitudinal contraction in the mouse proximal and distal colon.
Cumulative concentration–response curves to a range of ET agonists (ET‐1, ET‐2, ET‐3, (Ala1,3,11,13) ET and IRL 1620) were established by administering concentrations ranging from 0.01 nM to 0.3 μM. Concentration–response curves to ET‐1, which exhibits a high affinity for both ETA and ETB receptor subtypes, were also established in the presence of the ETA antagonist BMS 182874 and the ETB antagonist IRL1038.
The addition of the selective ETA receptor antagonist BMS 182874 caused a rightward shift of the concentration–response curve to ET‐1 in both sections of the colon. The ETB receptor antagonist IRL1038 (0.3–1 μM) did not significantly effect the response to ET‐1 in the proximal colon but caused a significant decrease in response towards higher concentrations ranges (3 nM) in the distal colon.
A comparison of the concentration–response curves to ET‐1, ET‐2 and ET‐3 showed a rank order of potency ET‐1ET‐2≫ET‐3 in the proximal colon and ET‐1ET‐2ET‐3 in the distal colon. The selective ETB receptor agonists, (Ala1,3,11,13) ET and IRL 1620 did not produce any response in the proximal sections of the colon but produced a smaller contraction in the distal segments.
The data indicate that ET can contract the proximal tissues of the mouse colon predominantly via ETA receptors and in the distal tissues via ETA and ETB receptors.

British Journal of Pharmacology (2006) 147, 607–611. doi:10.1038/sj.bjp.0706657
A small molecule, orally active, α4β1/α4β7 dual antagonist reduces leukocyte infiltration and airway hyper‐responsiveness in an experimental model of allergic asthma in Brown Norway rats
Authors: Cortijo Julio , Sanz María‐Jesús , Iranzo Arantxa , Montesinos José Luis , Nabah Yafa Naim Abu , Alfón José , Gómez Luis A , Merlos Manuel , Morcillo Esteban J 
Published: January 2006

α4β1 and α4β7 integrins are preferentially expressed on eosinophils and mononuclear leukocytes and play critical roles in their recruitment to inflammatory sites. We investigated the effects of TR14035, a small molecule, α4β1/α4β7 dual antagonist, in a rat model of allergic asthma.
Actively sensitized rats were challenged with aerosol antigen or saline on day 21, and the responses evaluated 24 and 48‐h later. TR14035 (3 mg kg−1, p.o.) was given 1‐h before and 4‐h after antigen or saline challenge.
Airway hyper‐responsiveness to intravenous 5‐hydroxytryptamine was suppressed in TR14035‐treated rats. Eosinophil, mononuclear cell and neutrophil counts, and eosinophil peroxidase and protein content in the bronchoalveolar lavage fluid (BALF) were decreased in TR14035‐treated rats. Histological study showed a marked reduction of lung inflammatory lesions by TR14035.
At 24‐h postchallenge, antigen‐induced lung interleukin (IL)‐5 mRNA upregulation was suppressed in TR14035‐treated rats. By contrast, IL‐4 levels in BALF were not significantly affected by TR14035 treatment.
IL‐4 selectively upregulates vascular cell adhesion molecule‐1 (VCAM‐1), which is the main endothelial ligand of α4 integrins. Intravital microscopy within the rat mesenteric microcirculation showed that 24‐h exposure to 1 μg per rat of IL‐4 induced a significant increase in leukocyte rolling flux, adhesion and emigration. These responses were decreased by 48, 100 and 99%, respectively in animals treated with TR14035.
In conclusion, TR14035, by acting on α4β1 and α4β7 integrins, is an orally active inhibitor of airway leukocyte recruitment and hyper‐responsiveness in animal models with potential interest for the treatment of asthma.

British Journal of Pharmacology (2006) 147, 661–670. doi:10.1038/sj.bjp.0706658