bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Biaryls Using the Coupling Reaction of Diaryldimethyltins with Copper(II) Nitrate
Authors: Harada Genta , Yoshida Masato , Iyoda Masahiko 
Published: May 2003

Abstract
The coupling of diaryldimethyltins with Cu(NO3)2·3H2O in THF proceeds smoothly at room temperature under ambient atmosphere to produce the corresponding biaryls in good to high yields. Diaryldimethyltins can be prepared in high yields by the reaction of aryllithiums with dichlorodimethyltin.
Selective Recognition of NH4+ over K+ with Tripodal Oxazoline Receptors
Authors: Ahn Kyo Han , Kim Sung-Gon , Jung Junyang , Kim Kyung-Hyun , Kim Jaheon , Chin Jik , Kim Kimoon 
Published: May 2003

Abstract
Benzene-based tripodal tris(oxazolines) are found to be promising receptors for the selective recognition of NH4+ over K+ with high binding affinities.
Lewis Acid Catalysis in Supercritical Carbon Dioxide. Use of Scandium Tris(heptadecafluorooctanesulfonate) as a Lewis Acid Catalyst in Diels-Alder and Aza Diels-Alder Reactions
Authors: Matsuo Jun-ichi , Tsuchiya Takehiro , Odashima Kazunori , Kobayashi Shu 
Published: May 2003

Abstract
Diels-Alder reactions of carbonyl dienophiles with dienes and aza Diels-Alder reactions of imines with a diene have been successfully carried out using scandium tris(heptadecafluorooctanesulfonate) (Sc(OSO2C8F17)3) as a Lewis acid catalyst in supercritical carbon dioxide (scCO2). It was revealed that the length of perfluorocarbon chains of the scandium catalyst was an essential factor for the catalytic activity in scCO2.
“Unlock-Lock” Approach to [2] and [3]Rotaxanes: Entering of a Ring through Disulfide Linkage That is Unlocked by Thiol “Key”
Authors: Furusho Yoshio , Hasegawa Toshihide , Tsuboi Akiyoshi , Kihara Nobuhiro , Takata Toshikazu 
Published: May 2003

Abstract
Bifunctional secondary ammonium salt bearing disulfide linkage at the center and bulky group at the both termini was mixed with dibenzo-24-crown-8. During reversible cleavage of the disulfide linkage catalyzed by benzenethiol, crown ether entered the disulfide linkage to afford corresponding [2] and [3]rotaxanes.
Layered Thin-Film Composite Consisting of Polymers and Calcium Carbonate: A Novel Organic/Inorganic Material with an Organized Structure
Authors: Kato Takashi , Suzuki Takuo , Irie Taku 
Published: May 2003

Abstract
Layered polymer/calcium carbonate (CaCO3) composite films have been successfully obtained by alternate repetition of spin-coating of polysaccharides and thin film crystallization of CaCO3 in the presence of an acid polymer. SEM images show layered structures consisting of brick of the inorganic crystal and mortar of the polymer.
Spirocycle-Incorporated Triphenylamine Derivatives as an Advanced Organic Electroluminescent Material
Authors: Kimura Makoto , Inoue Shin-ichiro , Shimada Kou , Tokito Shizuo , Noda Koji , Taga Yasunori , Sawaki Yasuhiko 
Published: May 2003

Abstract
For multi-color organic electroluminescent (EL) devices, new triphenylamine compounds attached to a spirocyclic framework were prepared from 2,7-bis(diphenylamino)-9-fluorenone. These amines showed exceedingly high Tg’s or thermal stability as well as good electrochemical properties and sufficient EL characteristics, allowing practical application.
Linkage Modes of Nickel(II) and Cobalt(III) Complexes with C-C Linked Bimacrocyclic Ligands
Authors: Mochizuki Katsura 
Published: May 2003

Abstract
The X-ray structural analysis revealed three types of linkage modes (eq-eq, ax-eq, and ax-ax) due to the stereochemical difference in bridging two macrocycles by a C-C bond for bimacrocyclic nickel(II) and cobalt(III) complexes.
Distribution Behavior of 2-Methyl-5-hexyloxymethyl-8-quinolinol between Supercritical CO2 and Water
Authors: Ohashi Kousaburo , Ishikawa Nobuhiro , Choi Sung-Yong , Imura Hisanori , Oriyama Takeshi 
Published: May 2003

Abstract
The distribution constants (KD,SF CO2) of 2-methyl-5-hexyloxymethyl-8-quinolinol (HMO6Q) between supercritical (SF) CO2 and water were determined at I = 0,1 M (H,Na)NO3 (1 M = 1 mol dm−3), 45 °C and 8.6 - 20.4 Mpa. The log KD,SF CO2 values at 8.6, 12.2, 15.7, and 20.4 Mpa were 1.18 ± 0.13, 1.76 ± 0.14, 2.18 ± 0.17, and 3.02 ± 0.21, respectively. The KD,SF CO2 value at 20.4 Mpa was about one tenth of that (log KD = 4.08 ± 0.02) for the heptane-water system at 45 °C and an atmosphere.
Control of Pore Structure of Trioctahedral Magnesium-Smectite Materials
Authors: Shirai Masayuki , Aoki Kuriko , Miura Takehiro , Torii Kazuo , Arai Masahiko 
Published: May 2003

Abstract
Micro-mesoporous smectite-type materials are prepared from water glass and magnesium chloride by a hydrothermal treatment and calcination without template materials. The addition of dialkyldimethyl ammonium chloride during or after the hydrothermal synthesis enlarged their pore volumes and mesopore sizes, due to changes in the size and orientation of constituent smectite fragments.
[2.2]Paracyclophane-Derived N-Acyloxazol-2(3H)-one as a Suitable Planar Chiral Auxiliary for the Enantioselective Synthesis of β-Hydroxy Acids
Authors: Fringuelli Francesco , Piermatti Oriana , Pizzo Ferdinando , Ruzziconi Reazo 
Published: May 2003

Abstract
The synthesis of optically active (+)-(R)-[2.2]paracyclophane-[4,5-d]-oxazol-2(3H)-one is described. The aldol reaction of N-acyl derivatives of this planar chiral auxiliary with beazaldehyde occurs with good diastereo- and enantioselectivity.
Four-Electron Reduction of Dioxygen Catalyzed by Self-doped Polyaniline-Co-porphyrin Complex
Authors: Yamamoto Kimihisa , Taneichi Daiki 
Published: May 2003

Abstract
The four-electron reduction of oxygen to water in a pseudo-neutral atmosphere(pH: 6.2) takes place on a glassy carbon electrode by electro-catalysis using the Co-porphyrin-polyaniline complex which shows a stable redox activity over a wide pH range due to the self-dopable carboxy substituents in the polymer chain.
Proton-Conduction of Perfluorooctanesulfonic Acid / Poly(propylene carbonate) Composites
Authors: Cho Jun-Sang , Hayashino Yuki , Miyatake Kenji , Takeoka Shinji , Tsuchida Eishun 
Published: May 2003

Abstract
To obtain proton-conducting organic materials with high conductivity under nonaqueous conditions, high thermal stability, and high resistance to acid, we prepared perfluorooctanesulfonic acid (FOSA)/ poly(propylene carbonate) (PPC) composites with different weight ratios. The composite with the weight ratios of 3 shows a high proton-conductivity of 1.9 × 10−5 S·cm−1 at 30 °C under nonaqueous conditions.
A Simple Synthetic Method for 3-Trifluoroacetylated 4-Aminoquinolines from 4-Dimethylaminoquinoline by Novel Trifluoroacetylation and N-N Exchange Reactions
Authors: Okada Etsuji , Sakaemura Takushi , Shimomura Naofumi 
Published: May 2003

Abstract
Acylation of 4-dimethylaminoquinoline with 1-trifluoroacetyl-4-dimethylaminopyridinium trifluoroacetate proceeded cleanly to give 3-trifluoroacetyl-4-dimethylaminoquinoline, which underwent nucleophilic aromatic substitutions with various amines to afford the corresponding N-N exchanged 3-trifluoroacetyl-4-aminoquinolines in excellent yields.
Preparation of Porous Chromia-Pillared Molybdenum Trioxide
Authors: Wang Xueguang , Hou Wenhua , Guo Xuefeng , Yan Qiejie 
Published: May 2003

Abstract
A chromia-pillared layered molybdenum trioxide has been prepared by combining a Cr(Oac)3 aqueous solution with a suspension of the molybdenum bronze for the first time; the resulting material after calcination at 350 °C is porous with a surface area of 82 m2 g−1.
Syntheses and Structures of Trimethylphosphine-complexed Primary Boryl Complexes of Group 8 Metals, Cp*M(CO)2(BH2·PMe3) (M = Fe, Ru)
Authors: Yasue Takahiro , Kawano Yasuro , Shimoi Mamoru 
Published: May 2003

Abstract
Photolysis of Cp*Fe(CO)2Me in the presence of BH3·PMe3 (1) produced a boryliron complex Cp*Fe(CO)2(BH2·PMe3) (2a). Complex 2a and the ruthenium analogue Cp*Ru(CO)2(BH2·PMe3) (3) were accessible by the salt-elimination reaction between K[Cp*M(CO)2] (M = Fe, Ru) and BH2Cl·PMe3.
Preparation of Colloidal Anatase TiO2 Secondary Submicroparticles by Hydrothermal Sol-Gel Method
Authors: Ito Seigo , Yoshida Shoichiro , Watanabe Tadashi 
Published: May 2003

Abstract
Anatase TiO2 nanoparticles giving stable colloids of tightly aggregated secondary particles were prepared by a hydrothermal sol-gel method. The average sizes of the primary and secondary particles, as estimated by TEM and DLS, were ca. 10 nm and ca. 100 nm, respectively. These particles were dispersed milky-whitely in water without any surfactant or polymer.
Photoexcited State Properties of C60 Encapsulated in a Water-Soluble Calixarene
Authors: Islam Shafiqul D-M , Fujitsuka Mamoru , Ito Osamu , Ikeda Atsushi , Hatano Tsukasa , Shinkai Seiji 
Published: May 2003

Abstract
Properties of the excited states of C60 incorporated into a cationic homooxacalix[3]arene (C60/calixarene) in water have been investigated and compared with bare C60 in benzene. A new transient absorption band which appeared at about 545 nm was attributed to triplet-triplet (T-T) absorption band of C60/calixarene. The λmax of the T-T transition shifts to the shorter wavelength compared with that of bare C60 in benzene and the decay rate increases very much.
Synthetic Studies toward Potent Cytotoxic Agents Amphidinolides: Synthesis of the C1-C6 and C9-C17 Moieties of Amphidinolides O and P
Authors: Chakraborty T K , Das Sanjib 
Published: May 2003

Abstract
Stereoselective synthesis of the (4R)-C1-C6 and (14R, 15R)-C9-C17 segments, 4 and 5 respectively, of amphidinolides O and P have been achieved starting from a common chiral precursor 6 which was obtained by radical-mediated opening of a trisubstituted epoxy alcohol using Cp2TiCl-cyclohexa-1,4-diene.
Remarkable Microenvironmental Difference between Monolayer and Bilayer Membrane Interfaces. Dissociation Behavior of a Lysine Residue Placed on the Membrane Surface
Authors: Ariga Katsuhiko , Abe Takao , Kikuchi Jun-ichi 
Published: May 2003

Abstract
The dissociation constant (pK) of an ε-amino group of the l-lysine residue in a cationic peptide lipid was evaluated for both the bilayer vesicle formed in aqueous media and monolayer membrane assembled at the air-water interface. The pK value of 9.4 in the aqueous vesicle evaluated using 1H-NMR spectroscopy was relatively close to that observed for the ε-amino group of lysine in water (10.5). In contrast, π-A isotherm measurements for the monolayer membrane on pure water revealed a remarkably shifted pK (5.1).
Effects of para-Substituents on the Reactivities of Sterically Congested Triplet Diphenylcarbenes
Authors: Hu Yingmo , Hirai Katsuyuki , Tomioka Hideo 
Published: May 2003

Abstract
Kinetically stabilized triplet di(2,6-dimethylphenyl)carbene is thermodynamically stabilized further by a spin-delocalizing para-substituent, whereby making the persistent triplet carbene longer-lived.
School adjustment in adolescence for previously rejected, average and popular children
Authors: Zettergren Peter 
Published: May 2003

Background: Earlier research shows that peer‐rejected children are at risk of a wide range of subsequent adjustment difficulties in different social contexts, as, for example, in school.Aims: This study investigated the academic performance and school adjustment in adolescence of children with different peer status in middle childhood.Sample: Age 15 boys and girls (N=90), who at age 10 and 11 were sociometrically rejected, popular, or of average popularity in their school class.Methods: School marks, intelligence scales, and self‐reports were used as adjustment measures. School dropout rate for boys was also included.Results: The academic performance and intelligence level of rejected boys and girls were short of the standards of children from the other status groups, while the scores of popular boys and girls were of superior standard. There were some slight indications that rejected girls (but not rejected boys) had negative attitudes towards school and schoolwork, and that popular girls had positive school attitudes. The school dropout rate of rejected boys was much higher than that of other boys.Conclusions: The results show that the rejected children are a risk group for school problems also over a long period of time. Considering the important developmental aspects of the adolescence years, there appear to be good reasons, therefore, to worry about the future adulthood adjustment of peer‐rejected children.
Erarbeitung von Methoden zur Erhöhung der Hydrophilie und Erniedrigung der elektrischen Aufladung von Polyamidfäden
Authors: Želtobrjuchov V. F. , Andričenko Ju. D. , Družinina T. V. , Gabrieljan G. A. , Morin B. P. , Rogovin Z. A. 
Published: May 2003

AbstractDas Problem einer stabilen Antistatikausrüstung von Polyamidfäden ist bisher noch ungelöst. Die Pfropfung von Poly‐2‐methyl‐5‐vinylpyridin ermöglicht das Einbringen unterschiedlicher funktioneller Gruppen in das Polymer. Der Einfluß solcher Gruppen auf die Wasseraufnahme und den elektrischen Volumenwiderstand von PA‐6‐Fäden wird untersucht. Außerdem wird die Wirkung von gepfropftem Polyvinylakohol betrachtet.
Die Wirkung elektrischer Hochfrequenz‐Entladungen auf Cellulose‐, Polyester‐ und Polypropylenfasern
Authors: Simionescu C. I. , Macoveanu M. M. , Olaru N. 
Published: May 2003

AbstractDie bei der Einwirkung elektrischer HF‐Entladungen auf Cellulose‐, Polyester‐ und Polypropylenfasern ablaufenden Prozesse, wie Abbau‐ und Vernetzungsreaktionen, Masseverlust, änderung der relativen Molekülmasse sowie der thermischen und mechanischen Eigenschaften, werden in Abhängigkeit von den Behandlungsbedingungen untersucht. Die in den Fasern entstehenden Makroradikale bilden bei Anwesenheit von Monomeren die Grundlage zur Synthese von Pfropfcopolymeren, wobei die HF‐behandelten Fasern als aktivierte Trägerpolymere dienen.
Polymerization of chlorophenylglycidyl ethers. IV. Influence of the composition of the initiator system: Aluminium isopropoxide‐zinc chloride on the polymerization of o‐chlorophenylglycidyl ether
Authors: Jedliński Z. , Bero M. , Dworak A. , Piechowiak E. 
Published: May 2003

AbstractInfluence of the composition of the initiator system employed on polymerization rate, molecular weight and structure of the polymer obtained was studied. At a zinc to aluminium ratio between 0.5 and 1, regular chain structure, and partly isotactic polymer was obtained. The dependence of polymerization rate and polymer molecular weight on the Zn/Al ratio in the initiator system was found to be of a very complex nature.
Reaktion und Diffusion bei der Schmelzepolykondensation von Polyethylenterephthalat
Authors: Rafler G. , Bonatz E. , Reinisch G. , Gajewski H. , Zacharias K. 
Published: May 2003

AbstractAuf der Grundlage eines Reaktions‐Diffusions‐Modells wurde die Reaktionsgeschwindigkeitskonstante der Bildung von Polyethylenterephthalat zu 1,20 · 10−2 g/mmol · s ermittelt. Für den Diffusionskoeffizienten von Ethylengykol in Polyethylenterephthalatschmelzen werden Werte in Abhängigkeit vom untersuchten Polymerisationsgradbereich angegeben. Der quantitativen Behandlung der Schmelzepolykondensation wurden Polykondensationsversuche in dünner Schicht zugrunde gelegt.
Einfluß von Molekülwechselwirkungen auf die radikalische Copolymerisation. III. UV‐spektroskopische Bestimmung von EDA‐Komplexbildungskonstanten in Comonomersystemen von Acrylnitril‐Styrol Sowie deren α‐Methylhomologen
Authors: Sandner B. , Krämer S. , An Bui‐Thi 
Published: May 2003

AbstractDie UV‐spektroskopisch bei 25°C in Cyclohexan bestimmten Elektronendonator‐Akzeptor(EDA)‐Komplexbildungs‐konstanten Kx (bezogen auf Molenbrüche) betragen für Acrylnitril‐Styrol 1,0, Methacrylnitril‐Styrol 0,5, Acrylnitril‐α‐Methylstyrol 1,1 und Methacrylnitril‐α‐Methylstyrol 1,1. Die Komplexbidungsenthalpien nehmen in der angegebenen Reihe der Comonomersysteme ab; demnach beeinflussen sterische Effekte die Komplexstabilität. Die Beteiligung von EDA‐Komplexen am Wachstumsschritt der Acrylnitril‐Styrol‐Copolymerisation in Substanz kann auf Basis der Komplexkonzentrationsverhältnisse in Betracht gezogen werden.
Zur Regulierung der Eigenschaften von Polymeren durch Emulsionspolymerisation
Authors: Eliseeva V. I. 
Published: May 2003

AbstractDie Struktur und damit auch das mechanische Verhalten sowie die physiko‐chemischen Eigenschaften von Latexfilmen lassen sich bei der Emulsionspolymerisation in unterschiedlicher Weise beeinflussen. Am Beispiel der Einführung einer kleinen Menge funktioneller Gruppen (N‐Methylol‐methacrylamid als hydrophiles Comonomer bzw. zur hydrolytischen Polykondensation befähigte Vinylalkoxysilane) bei der Polymerisation von Ethylacrylat sowie der unterschiedlichen Führung der Emulsionspolymerisation (Monomerdosierung, Impflatex, Mischlatices) wird gezeigt, daß in einer Reihe von Fällen eine wesentliche Verbesserung der mechanischen und pysiko‐chemischen Eigenschaften der Latexfilme erzielt werden kann, was bei der Herstellung von Filmen aus Lösungen dieser Polymere nicht der Fall ist, da die spezifische Struktur der Latexfilme dabei zerstört wird.
Zur physikalischen Struktur der Cellulose
Authors: Grican V. N. , Žbankov R. G. , Kačur V. G. 
Published: May 2003

AbstractIn der Arbeit wird die physikalische Struktur der Cellulose diskutiert. Neue Ergebnisse theoretischer Untersuchungen der Makromolekülkonformationen sowie der intra‐ und intermolekularen Wasserstoffbindungen in der Cellulose werden mitgeteilt.
Zur Herstellung von ionenaustauschenden Polycaproamidfasern. Teil I. Anilinformaldehydharz enthaltende Polycaproamidfasern
Authors: Gankov N. , Dimov K. , Pavlov P. , Dimitrov D. , Simeonov N. , Terlemesjan E. , Simeonska T. 
Published: May 2003

AbstractEin neues Verfahren zur Herstellung ionenaustauschender Polycaproamidfasern, das auf der Synthese von Anilinformaldehydharz in der Fasermasse beruht, wurde entwickelt. Der Einfluß verschiedener Faktoren auf den Verlauf der Synthesereaktion wurde untersucht. Unter optimalen Bedingungen wurden ionenaustauschende Polycaproamidfasern mit einer Austauschkapazität von 2,71 mgäqu./g gegenüber 0,1 n HCl erhalten.
Developmental model relating white matter volume to neurocognitive deficits in pediatric brain tumor survivors
Authors: Reddick Wilburn E. , White Holly A. , Glass John O. , Wheeler Gregory C. , Thompson Stephen J. , Gajjar Amar , Leigh Laurie , Mulhern Raymond K. 
Published: May 2003

AbstractBACKGROUNDThe primary objective of this study was to test the hypothesis that, among survivors of pediatric brain tumors, the association between reduced volumes of normal‐appearing white matter (NAWM) and intellectual/academic achievement deficits can be explained by patient problems with memory and attention.METHODSQuantitative tissue volumes from magnetic resonance imaging scans and neurocognitive assessments were obtained for 40 long‐term survivors of pediatric brain tumors. They were treated with radiotherapy (RT) with or without chemotherapy 2.6–15.3 years earlier (median, 5.7 years) at an age of 1.7–14.8 years (median, 6.5 years). Neurocognitive assessments included standardized tests of intellect (intelligence quotient [IQ]), attention, memory, and academic achievement.RESULTSAnalyses revealed significant impairments in patients' neurocognitive test performance on all measures. After statistically controlling for age at RT and time from RT, significant associations were found between NAWM volumes and both attentional abilities and IQ, and between attentional abilities and IQ. Subsequent analyses supported the hypothesis that attentional abilities, but not memory, could explain a significant amount of the relationship between NAWM and IQ. The final developmental model predicting academic achievement based on NAWM, attentional abilities, and IQ explained approximately 60% of the variance in reading and spelling and almost 80% of the variance in math.CONCLUSIONSThe authors demonstrated that the primary consequence of reduced NAWM among pediatric patients treated for brain tumors was decreased attentional abilities, leading to declining IQ and academic achievement. Cancer 2003;10:2512–9. © 2003 American Cancer Society.DOI 10.1002/cncr.11355
Malignancy in giant cell tumor of bone
Authors: Bertoni Franco , Bacchini Patrizia , Staals Eric L. 
Published: May 2003

AbstractBACKGROUNDThe term malignant giant cell tumor embraces multiple entities and therefore can be confusing. The goals of the current study were to define the clinicopathologic and histologic features of malignancy in giant cell tumors and to clarify the terminology.METHODSThe authors reviewed all cases from the Rizzoli Institute (Bologna, Italy) of primary (PMGCT) and secondary (SMGCT) malignancy in giant cell tumors. PMGCT is a high‐grade sarcoma that arises side by side with benign giant cell tumors. SMGCT is a high‐grade sarcoma that occurs at the sites of previously treated giant cell tumors of bone.RESULTSThe authors report 5 PMGCTs and 12 SMGCTs; half of the SMGCTs were postradiation sarcomas. Patient age ranged from 20 to 68 years (median, 62 years) for PMGCT and from 30 to 77 years (median, 40 years) for SMGCT. The average latent period between diagnosis of giant cell tumor and diagnosis of SMGCT was 9 years (range, 3–15 years) for patients with postradiation SMGCT and 19 years (range, 7–28 years) for patients with SMGCT resulting from spontaneous transformation. The histologic classification of high‐grade sarcomas in the PMGCT group was osteosarcoma in four cases and malignant fibrous histiocytoma in one case. In the SMGCT group, the histologic classification was osteosarcoma in nine cases, fibrosarcoma in two cases, and malignant fibrous histiocytoma in one case. The outcomes associated with all malignancies in giant cell tumors were poor, with the worst outcome associated with postradiation SMGCT.CONCLUSIONSMalignancies in giant cell tumors of bone always are high‐grade sarcomas with a poor prognosis. These lesions must be distinguished from benign giant cell tumors of bone. SMGCT usually is easy to diagnose upon malignant clinicoradiographic presentation. In contrast, PMGCT often mimics giant cell tumors both clinically and radiographically. In addition, upon histologic examination, PMGCT shows areas of conventional giant cell tumor, which can lead to difficulties in making the correct diagnosis. Cancer 2003;97:2520–9. © 2003 American Cancer Society.DOI 10.1002/cncr.11359