bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). IV. Nonisothermal crystallization
Authors: Kratochvíl J. , Sikora A. 
Published: December 2004

AbstractNonisothermal crystallization of poly(N‐methyldodecano‐12‐lactam) (MPA) was investigated using DSC method at cooling rates of 2–40 K/min. With increasing cooling rate, crystallization exotherms decreased in magnitude and shifted toward lower temperatures. Subsequent heating runs (10 K/min) showed an exotherm just above Tg, which increased in magnitude with the rate of preceding cooling run, corresponding to the continuation of primary crystallization interrupted as the system crossed Tg on cooling. Kinetic evaluation by the Avrami method gave values of exponent n close to 2.0, suggesting two‐dimensional crystal growth combined with heterogeneous nucleation. The Tobin method, covering the intermediate range of relative crystallinities, provided n ≅ 2.20, suggesting possible partial involvement of homogeneous nucleation at later stages of nonisothermal crystallization. The crystallization rate parameter k1/n showed a linear dependency on cooling rate for both methods, the Tobin values being slightly higher. The Ozawa approach failed to provide reasonable values of the kinetic exponent m of MPA. The Augis–Bennet method was used to determine the effective activation energy of the entire nonisothermal crystallization process of MPA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 564–572, 2005
Synthesis of the glycidyl aniline adduct and its crosslinking
Authors: Gawdzik Barbara , Matynia Tadeusz , Kovtun Oksana 
Published: December 2004

AbstractSynthesis of the adduct of aniline and glycidyl methacrylate and its polymerization and copolymerization with two diisocyanates are presented. Hexyl diisocyanate representing aliphatic compounds and toluene diisocyanate as the aromatic compound were used. UV and thermal initiations were applied. The curing process was controlled by FTIR analysis. Thermomechanical properties of the compositions cured at different temperatures were compared. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 524–528, 2005
Chemical oxidative grafting of conducting poly(N‐methyl aniline) onto poly(ethylene terepthalate)
Authors: Santhosh P. , Mathanmohan T. , Sankarasubramanian M. , Sankar S. , Vasudevan T. , Gopalan A. , Lee Kwang‐Pill 
Published: December 2004

AbstractDetailed studies on the peroxidisulfate (PDS) initiated graft copolymerization of N‐methyl aniline (NMA) with poly(ethylene terepthalate) (PET) were carried out in p‐tolene sulfonic acid medium under nitrogen atmosphere. Experiments were designed to follow the rate of formation Rh of the poly(N‐methyl aniline (PNMA), simultaneously with the rate of grafting of PNMA onto PET. Effects of concentration of NMA, PDS, PET, time, and temperature on Rh and graft parameters were followed. Kinetic equations were deduced to correlate the changes in the rate with experimental conditions. Graft copolymers were isolated and grafting of PNMA onto PET was confirmed through FTIR, thermogravimetric analysis, and conductivity measurements. Tensile measurements showed that grafting of PNMA did not alter the tensile properties of PET. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 596–605, 2005
Aromatic polyesters based on bisphenol‐A for liquid insulating systems: A synthetic approach
Authors: Shenoy M. A. , Pereira E. A. , Parikh P. F. 
Published: December 2004

AbstractThis work concentrates on the area of the synthesis of polymers for liquid insulating systems. We have studied reactions of aromatic esters like diphenyl terephthalate/isophthalate, diphenyl carbonate with Bisphenol‐A, and tri functional glycerol for the synthesis of aromatic polyesters that can be used as liquid insulating systems. The process comprises a transesterification resin synthesis based on a single pot process, with a temperature profile up to 250°C and an inert atmosphere of nitrogen. The byproduct of the phenol is continuously removed under a steady flow of nitrogen to enable polycondensation. The resins obtained were tested for their physical properties, such as melting range, relative viscosity, and hydroxyl value. These resins were also used in solution film formation to establish their film forming properties. The method explored is the simplest one, and permits the use of commercial materials as the feedstock. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 606–614, 2005
Cystathionine β synthase deficiency affects mouse endochondral ossification
Authors: Robert Karine , Maurin Nicole , Vayssettes Catherine , Siauve Nathalie , Janel Nathalie 
Published: December 2004

AbstractCystathionine β synthase (CBS) is a crucial regulator of plasma concentrations of homocysteine. Severe hyperhomocysteinemia due to CBS deficiency confers diverse clinical manifestations, notably characteristic skeletal abnormalities. To investigate this aspect of hyperhomocysteinemia, we analyzed the skeleton of CBS‐deficient mice, a murine model of severe hyperhomocysteinemia. Radiography, Alcian Blue/Alizarin Red S‐stained whole skeletal preparations, and histological comparisons were used to determine the extent, pattern, and distribution of skeletal abnormalities in CBS‐deficient mice. Disruption of the murine CBS gene leads to skeletal abnormalities, notably kyphoscoliosis, with temporal shortening of long bones due to impaired cartilage differentiation, albeit to differing degrees. © 2004 Wiley‐Liss, Inc.
Rodent pharmacokinetics and receptor occupancy of the GABAA receptor subtype selective benzodiazepine site ligand L‐838417
Authors: Scott‐Stevens P. , Atack J.R. , Sohal B. , Worboys P. 
Published: December 2004

AbstractThe pharmacokinetics of L‐838417, a GABAA receptor subtype selective benzodiazepine site agonist, were studied in rats and mice after single oral (p.o.), intraperitoneal (i.p.) and intravenous (i.v.) doses. In both species L‐838417 was well absorbed following i.p. administration and whilst in rats p.o. bioavailability was good (41%), in mice it was negligible (<1%), precluding this as a route of administration for mouse behavioural studies. Despite having a similar volume of distribution (ca 1.4 l/kg) in rats and mice, L‐838417 was cleared at twice liver blood flow in mice (161 ml/min/kg) and moderately cleared in rats (24 ml/min/kg), potentially explaining the poor oral bioavailability in mice. Finally, as a pharmacodynamic readout the benzodiazepine binding site occupancy was determined in rats (0.3–3 mg/kg, p.o.) and mice (1–30 mg/kg, i.p.) using a [3H]Ro 15‐1788 in vivo binding assay. Although the resulting dose‐occupancy relationship for both species demonstrated a dose‐dependent increase in receptor occupancy, appreciable variability was observed at low dose levels, potentially making interpretation of behavioural responses difficult. In contrast, a clear relationship between plasma and brain concentrations and receptor occupancy were determined suggesting the observed dose‐occupancy variability is a consequence of the pharmacokinetic properties of L‐838417. The plasma and brain concentrations required to occupy 50% of the benzodiazepine binding sites were similar in both rats (28 ng/ml and 33 ng/mlg, respectively) and mice (63 ng/ml and 53 ng/mlg, respectively), with a non‐linear concentration response observed with increasing doses of L‐838417. These studies demonstrate the importance of utilizing pharmacokinetic/receptor occupancy data when interpreting pharmacodynamic responses at a given dose. Copyright © 2004 John Wiley & Sons, Ltd.
Topological Analysis of Electron Densities: Is the Presence of an Atomic Interaction Line in an Equilibrium Geometry a Sufficient Condition for the Existence of a Chemical Bond?
Authors: Haaland Arne , Shorokhov Dimitry J. , Tverdova Natalya V. 
Published: December 2004

AbstractContrary to the published acknowledgement, Professor R. F. W. Bader in no way contributed to any of arguments presented in this paper; he has indicated that all of the criticisms raised by the authors were previously discussed and rebuted in J. Chem. Phys. A 1998, 102, 7314.A copy of an earlier version of the manuscript was sent to Professor Bader last spring, and the e‐mail correspondence that followed made it very clear that he disagreed strongly with the conclusions. The authors nevertheless found the discussion useful, since it clarified the nature of the disagreement. Professor Bader's queries also prompted the authors to calculate the dissociation energy of the He@adam inclusion complex and to determine the structure of the transition state as discussed in the article. The authors apologize for omitting to ask for Professor Bader's permission to include his name among the acknowledgements.
Novel π‐Extended Donors Containing a 2,2,5,5‐Tetramethylpyrrolin‐1‐yloxyl Radical Designed for Magnetic Molecular Conductors.
Authors: Fujiwara Emiko , Kobayashi Akiko , Fujiwara Hideki , Sugimoto Toyonari , Kobayashi Hayao 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Intermolecular “Oxidative” Aromatic Substitution Reactions of the Imidazol‐5‐yl Radical Mediated by the “Reductant” Bu3SnH.
Authors: McLoughlin Padraig T. F. , Clyne Mairead A. , Aldabbagh Fawaz 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Syntheses of Sulfoxide Derivatives in the Benzodiazine Series. Diazines. Part 37.
Authors: Le Fur Nicolas , Mojovic Ljubica , Turck Alain , Ple Nelly , Queguiner Guy , Reboul Vincent , Perrio Stephane , Metzner Patrick 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Catalytic Nanomotors: Autonomous Movement of Striped Nanorods.
Authors: Paxton Walter F. , Kistler Kevin C. , Olmeda Christine C. , Sen Ayusman , St. Angelo Sarah K. , Cao Yanyan , Mallouk Thomas E. , Lammert Paul E. , Crespi Vincent H. 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Large‐Scale Production of NbS2 Nanowires and Their Performance in Electronic Field Emission.
Authors: Jin Yi Zheng , Hsu Wen Kuang , Chueh Yu Lun , Chou Li Jen , Zhu Yan Qiu , Brigatti Kieren , Kroto Harold W. , Walton David R. M. 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Metal‐Assisted Polyhedral Contraction Reactions of Monocarbon and Dicarbon Carbaborane Species Involving nido‐{CB10}, nido‐{CB9}, nido‐{C2B8} and exo‐nido‐{C2B9Os} Systems
Authors: Pisareva I. V. , Konoplev V. E. , Balagurova E. V. , Yanovsky A. I. , Dolgushin F. M. , Cheredilin D. N. , Chizhevsky I. T. , Franken A. , Carr M. J. , Thornton‐Pett M. , et al. et al. 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Direct Insertion into Twelve‐Vertex Metallacarboranes
Authors: Kudinov Alexander R. , Perekalin Dmitry S. , Rynin Stanislav S. , Lyssenko Konstantin A. , Grintselev‐Knyazev Gennadii V. , Petrovskii Pavel V. 
Published: December 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
N‐Ferrocenyl‐Substituted Planar‐Chiral N‐Heterocyclic Carbenes and Their PdII Complexes
Authors: Bertogg Andreas , Camponovo Francesco , Togni Antonio 
Published: December 2004

AbstractThe N‐ferrocenyl‐linked N‐heterocyclic carbenes 1a and 1b were obtained by treatment of their imidazolium salts 12a and 12b with potassium tert‐butoxide. The latter were shown to be accessible from (R)‐1‐amino‐2‐methylferrocene (9) and aminoferrocene, respectively, which were converted into the corresponding formamidines and then subjected to a novel cyclization procedure. Treating the ligand precursors 12a and 12b with [Pd(OAc)2]3 under different reaction conditions afforded the trans‐pyridine‐substituted PdII complexes 14a and 14b as well as their trans‐triphenylphosphane‐substituted counterparts 16a and 16b and, in the case of the chiral ligand precursor, the dinuclear PdII complex 15a. Conformational analysis of the ligands based on the X‐ray structures of 12a, 12b and 16a revealed the dependence of the two torsion angles between the central imidazolium core and the adjacent ferrocenyl substituents on the steric and electronic properties of the observed systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Base Strengths of Substituted Tritylamines, N‐Alkylanilines, and Tribenzylamine in Aqueous Solution and the Gas Phase: Steric Effects Upon Solvation and Resonance Interactions
Authors: Canle L. Moisés , Demirtas Ibrahim , Freire Antonio , Maskill Howard , Mishima Masaaki 
Published: December 2004

AbstractThe dissociation constants of the conjugate acids of N‐tritylacetamide (1h; pK = 3.81) and N‐benzyl‐N‐methyl‐4,4′,4′′‐trimethoxytritylamine (4i; pK = 9.86) have been measured in aqueous acetonitrile at 25 °C and at other temperatures to determine the enthalpies and entropies of reaction. For 1h, ΔH⊖ = 40.7 kJ·mol−1 and ΔS⊖ = 64 J·K−1·mol−1, and for 4i ΔH⊖ = 9.1 kJ·mol−1 and ΔS⊖ = −159 J·K−1·mol−1. In addition, gas‐phase base strengths at 25 °C (GB values in kJ·mol−1) of TrNH2 (1a; 902.1), TrNHPh (1c; 926.3), TrNHAc (1h; 929.7), TrNHC6H4(o‐NO2) (1i; 895.0), DMTrNH2 (3a; 921.3), DMTrNHCH2CO2Me (3b; 879.1), and DMTrNH(p‐NO2Bn) (3d; 886.6) have been determined by ICR measurements. The GB of TrNHAc corresponds to protonation at oxygen and B3LYP/6‐31G* calculations indicate that the N‐protonated isomer is 46.4 kJ·mol−1 less stable, i.e. the GB value for N‐protonation is 883.3 kJ·mol−1. Correspondingly, the literature GB value of 857.6 5 kJ·mol−1 for N‐methylacetamide corresponds to protonation at oxygen, and B3LYP/6‐31G* calculations indicate that the N‐protonated isomer is 58.1 kJ·mol−1 less stable, i.e. the GB value for N‐protonation of MeNHAc is 799.5 kJ·mol−1. The GB of PhNH(tBu) (5; 920.1 kJ·mol−1) has been measured and compared with values for other N‐alkylanilines, PhNHR, including PhNHTr; the results indicate that the increasing GB values as R increases in size are due solely to the increasing polarisability of R. This indicates that the increasing solution base strength of PhNHR as R increases in size is a solvation effect and is not due to decreasing resonance interactions between the nitrogen lone‐pair and the phenyl ring. Similarly, the base‐strengthening effect in solution of the (substituted) trityl in TrNHZ, where Z is an alkyl with an electron‐withdrawing group, is shown to be due to solvation phenomena as it is absent in the gas phase; for one such compound, TMTrNHCH2CO2Me (4b; pK = 9.30), ΔH⊖ = 17.9 kJ·mol−1 and ΔS⊖ = −118 J·K−1·mol−1. In contrast, the difference in solution base strengths between MeNHAc (pK = −0.56) and TrNHAc (pK = 3.81) is attributed, at least in part, to a reduced base‐weakening resonance interaction between the lone pair on N and the acetyl group in TrNHAc, as the effect is also evident in the gas phase. The GB value for tribenzylamine (6) has also been measured (965.2 kJ·mol−1) and is unexceptional; this indicates that the low base strength of 6 in aqueous solution (pK = 4.90 at 25 °C) is a solvation effect which is expressed mainly through an abnormally large positive entropy of reaction (ΔS⊖ = 76 J·K−1·mol−1), the value of ΔH⊖ (50.5 kJ·mol−1) being only slightly larger than normal for tertiary amines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of the First Tetracene‐[60]fullerene Dyad
Authors: Taillemite Sébastien , Fichou Denis 
Published: December 2004

AbstractWe report on a multistep synthesis of the newly designed tetracene‐[60]fullerene dyad involing a Bingel reaction between the tetracene and C60 moieties. This strategy prevents the usual Diels−Alder reaction which would result in the loss of the tetracene aromaticity in the target dyad. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Encapsulation and Stabilization of Reactive Aromatic Diazonium Ions and the Tropylium Ion Within a Supramolecular Host
Authors: Brumaghim Julia L. , Michels Martin , Pagliero Daniela , Raymond Kenneth N. 
Published: December 2004

AbstractSupramolecular assemblies with internal cavities are being developed as nanoscale reaction vessels to protect or modify the reactivity of guest species through encapsulation. Diazonium cations and the tropylium cation were examined for their ability to encapsulate in the tetrahedral [Ga4L6]12− supramolecular assembly. The 4‐(diethylamino)benzenediazonium cation 1 readily formed a 1:1 host−guest complex with this assembly, and this encapsulation prevented 1 from reacting with 2,4‐pentanedione in D2O. The tropylium cation also formed a 1:1 host−guest complex with the [Ga4L6]12− assembly, greatly slowing its decomposition in D2O. Encapsulation in the protected environment of this host cavity alters the reactivity of these guest molecules, giving them greater stability. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Silylation‐Mediated Transesterification of O‐Phenyl H‐Phosphonothioates − A New Entry to Nucleoside H‐Phosphonothioate Monoesters
Authors: Lavén Gaston , Nilsson Johan , Stawinski Jacek 
Published: December 2004

AbstractO‐Phenyl H‐phosphonothioate undergoes a facile transesterification with suitably protected nucleosides upon in situ silylation with tert‐butyldiphenylsilyl chloride in pyridine/ toluene to produce the corresponding 3′‐H‐phosphonothioates in good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tris(pentafluorophenyl)silyl Triflate: Synthesis and Silylation of Carbonyl Compounds
Authors: Levin Vitalij V. , Dilman Alexander D. , Belyakov Pavel A. , Korlyukov Alexander A. , Struchkova Marina I. , Tartakovsky Vladimir A. 
Published: December 2004

AbstractTris(pentafluorophenyl)silyl triflate (1) was prepared by protodesilylation of phenyl‐, allyl‐, and isopropenyloxytris(pentafluorophenyl)silyl derivatives and characterized by X‐ray crystallography. This reagent was employed for the silylation of carbonyl compounds. Aldehydes and ketones afforded the corresponding silyl enol ethers in good yields, while silylation of esters and lactones was dependent on the reaction conditions and on the substrate. A mechanism accounting for the observed phenomena is proposed. Studies of the relative reactivities of 1 and trimethylsilyl triflate are also presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
High‐resolution gene copy number and expression profiling of human chromosome 22 in ovarian carcinomas
Authors: Benetkiewicz Magdalena , Wang Yun , Schaner Marci , Wang Pei , Mantripragada Kiran K. , Buckley Patrick G. , Kristensen Gunnar , Børresen‐Dale Anne‐Lise , Dumanski Jan P. 
Published: December 2004

AbstractPrevious low‐resolution studies of chromosome 22 in ovarian carcinoma have suggested its involvement in the development of the disease. We report a high‐resolution analysis of DNA copy number and gene expression of 22q in 18 ovarian carcinomas using a 22q‐specific genomic microarray. We identified aberrations in 67% of the studied tumors, which displayed 3 distinct gene copy number profiles. The majority of the cases (11 of 18) demonstrated heterozygous terminal deletions of various sizes, the smallest of which was 3.5 Mb. The second profile, detected in 3 tumors, revealed the coexistence of heterozygous deletions and different patterns of low‐copy‐number gain that involved the proximal half of 22q. The latter finding has not been reported previously in ovarian carcinoma. One case displayed a continuous deletion encompassing the entire 22q, consistent with monosomy 22. Furthermore, we compared the results with the available data on these tumors by using cDNA microarrays to define the degree of correlation between abnormalities at the DNA level and variation in mRNA expression. By a comparison with the expression data, we were able to identify 21 deleted genes showing low mRNA levels and 12 amplified genes displaying elevated gene expression, several of which play roles in cell cycle control and the induction of apoptosis. Our results indicated significant correlation between DNA copy number aberrations and variation in mRNA expression. We also identified several regions and candidate genes on 22q that should be studied further to determine their role in the development of ovarian cancer. © 2004 Wiley‐Liss, Inc.
In vivo analysis of oligodendrocyte lineage development in postnatal FGF2 null mice
Authors: Murtie Joshua C. , Zhou Yong‐Xing , Le Tuan Q. , Armstrong Regina C. 
Published: December 2004

AbstractAnalysis of fibroblast growth factor 2 null (FGF2−/−) and wild‐type (FGF2+/+) mice was used to interpret the potential in vivo role of endogenous FGF2 on oligodendrocyte lineage cell (OLC) responses during oligodendrogenesis and myelination. In wild‐type mouse spinal cord, FGF2 levels increased approximately threefold between the first and second postnatal weeks, a period corresponding with the peak of oligodendrogenesis. Absence of this developmental FGF2 elevation in FGF2−/− mice eliminated the transient overproduction of oligodendrocytes that is known to occur at the peak of oligodendrogenesis in wild‐type mice. Absence of FGF2 did not affect oligodendrocyte progenitor (OP) density or proliferation, based on BrdU incorporation, and also did not alter survival, based on TUNEL analysis. To examine OLC differentiation in vivo, retrovirus encoding‐enhanced green fluorescent protein (GFP) was injected into the spinal cord to heritably label endogenous cycling cells in the white matter at postnatal day 7 and then identify the generated cells at postnatal day 28. Phenotypes of cells expressing GFP were identified by morphology and immunolabeling, using CC1 for oligodendrocytes and NG2 combined with platelet‐derived growth factor α receptor for OPs. Within the population of GFP‐labeled cells, the proportion of oligodendrocytes was higher in FGF2−/− mice, indicating that endogenous FGF2 inhibited OLC differentiation in wild‐type mice. Furthermore, in FGF2−/− mice fewer cells appeared to be generated from an initial retrovirus‐labeled cell, consistent with more frequent differentiation into post‐mitotic oligodendrocytes. This in vivo analysis demonstrates that the predominant role of endogenous FGF2 on OLCs in development is inhibition of differentiation. © 2004 Wiley‐Liss, Inc.
Analysis of allelic imbalances at multiple cancer‐related chromosomal loci and microsatellite instability within the same tumor using a single tumor gland from colorectal carcinomas
Authors: Sugai Tamotsu , Habano Wataru , Jiao Yu‐Fei , Suzuki Masamichi , Takagi Ryo , Otsuka Koki , Higuchi Taro , Nakamura Shin‐Ichi 
Published: December 2004

AbstractGenetic changes related to colorectal carcinomas are accumulated in individual tumor glands during disease progression. Microsatellite allelic analysis of individual tumor glands from 30 colorectal carcinomas using a polymerase chain reaction (PCR) assay coupled with crypt isolation was used to detect intratumoral genetic heterogeneity, the sequence of allelic imbalances (AIs) and the microsatellite instability status of single tumor glands during neoplastic progression. In addition, the CpG islands methylated phenotype (CIMP) status was examined using a methylation‐specific PCR method. The specimens were divided into 2 groups: a pooled gland sample, which was composed of more than 50 tumor glands, and a single tumor gland sample. The latter consisted of 10 single tumor glands, which were obtained from the same tumor separately. Most colorectal carcinomas (27 of 30 tumors) examined were heterogeneous for at least one genetic alteration, with from 2 to 7 genotypically different subclones detected per tumor. In 12 of the 27 heterogeneous tumors, it was possible to define the order of genetic alterations during the tumor progression. By analyzing multiple single tumor glands within the same tumor, we found that various subclonal expansions were seen within the same tumors. Finally, the AI pattern of single tumor glands was not correlated with CIMP status. Most carcinomas appeared to have a heterogeneous composition. This may have resulted from the successful progression of one clone that had different AIs in many chromosomal regions. This suggests that knowledge of the different genotypes of multiple single tumor glands may help clarify the process of tumor progression. © 2004 Wiley‐Liss, Inc.