bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural characterization and mechanical behavior of metallocenic copolymers of ethylene and 5,7‐dimethylocta‐1,6‐diene
Authors: Cerrada María L. , Benavente Rosario , Pereña José M. , Pérez Ernesto , Moniz‐Santos Jorge , Ribeiro M. Rosário 
Published: June 2004

AbstractThe relationships between structure and mechanical properties have been established in several copolymers of ethylene and 5,7‐dimethylocta‐1,6‐diene synthesized by a metallocene catalyst. A dependence with composition and polymerization temperature has been found for different structural and mechanical parameters. The branches cannot be incorporated into the orthorhombic crystal lattice and, consequently, structural parameters such as crystallinity and crystal size are considerably affected as 5,7‐dimethylocta‐1,6‐diene content increases in the copolymer. These structural changes influence significantly the rigidity of the copolymers and a decrease of this parameter, determined from either storage modulus or microhardness, with increasing 5,7‐dimethylocta‐1,6‐diene molar fraction is found. The location of the different viscoelastic relaxations is also strongly dependent on composition.
Polymacromonomers with polyolefin branches synthesized by free‐radical homopolymerization of polyolefin macromonomer with a methacryloyl end group
Authors: Kaneko Hideyuki , Kojoh Shin‐ichi , Kawahara Nobuo , Matsuo Shingo , Matsugi Tomoaki , Kashiwa Norio 
Published: June 2004

AbstractPolymacromonomers with polyolefin branches were successfully synthesized by free‐radical homopolymerization of polyolefin macromonomer with a methacryloyl end group. Propylene‐ethylene random copolymer (PER) with a vinylidene end group was prepared by polymerization using a metallocene catalyst. Then, the unsaturated end group was converted to a hydroxy end group via hydroalumination and oxidation. The PER with the hydroxy end group was easily reacted with methacryloyl chloride to produce methacryloyl‐terminated PER (PER macromonomer; PERM). The free‐radical polymerization of thus‐obtained PERM was done using 2,2′‐azobis(isobutyronitorile) (AIBN) as a free‐radical initiator. From NMR analyses, the obtained polymers were identified as poly(PERM). Based on gel permeation chromatography (GPC), the estimated degree of polymerization (Dp) of these polymers were about 30. Thus, new class of polymacromonomers with polyolefin branches was synthesized.
Polymerization with Fischer‐Tropsch olefins – a new challenge in polymer science
Authors: Tincul Ioan , Lufuno Siphuma , Rawatlal Randhir 
Published: June 2004

AbstractCo‐ and ter‐polymerization of ethylene with Fischer‐Tropsch derived olefins having odd carbon number and branched olefins are investigated. A method of preparation of a robust, high productivity Ziegler‐Natta catalyst suitable for ethylene co‐polymerization with Fischer Tropsch olefin is reviewed. In supporting titanium tetrachloride, an attempt was made to control the titanium oxidation state. The resulting experimental data were fitted to a sub‐sites model that associates titanium oxidation state with catalyst activity.
Comparative analysis of the clathrate forms of syndiotactic polystyrene, poly (p‐methylstyrene) and poly (m‐methylstyrene)
Authors: Petraccone Vittorio , Tarallo Oreste 
Published: June 2004

AbstractThe crystal structures of the clathrate forms of syndiotactic polystyrene (s‐PS), poly (p‐methylstyrene) (s‐PPMS) and poly (m‐methylstyrene) (s‐PMMS) containing guest molecules having widely different steric hindrance are compared in detail. Common features and differences concerning the packing of the chains, the shape and the dimensions of the cavities and the stability of the forms deprived of the guest molecules are pointed out. A new clathrate form of s‐PPMS containing CS2 is also described.
A Semi‐Microscopic Modeling for Polymer Flow Reactors
Authors: Hua Chi C. , Hsu Fu Y. , Chang Mu G. , Kan Chun J. 
Published: June 2004

AbstractSummary: A nonisothermal plug‐flow reactor for ethylene polymerization is reexamined so as to illustrate the principle and effect of a refined, semi‐microscopic modeling. The novel feature of the current simulation is the application of a Monte Carlo scheme to exactly solve the free‐radical polymerization involved, whereas a reptation‐based molecular theory is introduced in a self‐consistent manner to simulate more accurately the reactant fluid viscosity during polymerization. The simulation is shown to capture some in‐depth consequences of reaction‐transport coupling that cannot be revealed by a traditional, macroscopic type of modeling. The principle of a future extension for dealing with more complex flow reactors is briefly discussed.Comparison of the predicted temperature profile between Monte Carlo‐based simulation and the ones using moment equations together with two different weight distributions is shown with experimental data for LDPE.imageComparison of the predicted temperature profile between Monte Carlo‐based simulation and the ones using moment equations together with two different weight distributions is shown with experimental data for LDPE.
Alterations of the Dutt1/Robo1 gene in lung adenocarcinomas induced by N‐nitrosobis(2‐hydroxypropyl)amine in rats
Authors: Tsujiuchi Toshifumi , Sasaki Yasutaka , Oka Yasuo , Kuniyasu Hiroki , Tsutsumi Masahiro 
Published: June 2004

AbstractAbnormalities of tumor suppressor genes (TSGs) on chromosome 3p are known to be important for the development of human lung cancers. In the present study, we investigated alterations of the Dutt1/Robo1 gene, as a possible tumor suppressor in this region, in rat lung adenocarcinomas induced by N‐nitrosobis(2‐hydroxypropyl)amine (BHP). Male Wistar rats, 6‐wk‐old, were given 2000 ppm BHP in their drinking water for 12 wk and maintained without further treatment until killed at wk 25. A total of 12 lung adenocarcinomas were obtained and total RNAs were extracted from each for assessment of aberrant transcripts of the Dutt1/Robo1 gene by reverse transcription (RT)‐polymerase chain reaction (PCR) analysis. Aberrant transcripts bearing deletions of nucleotides (nt) 55–4318, 89–4346, 605–4221, and 929–4318 were detected in four of 12 adenocarcinomas (33.3%). Loss or reduced expression of the Dutt1/Robo1 gene was not found in any of the adenocarcinomas. Genomic DNAs extracted from six adenocarcinomas for Southern blot analysis did not show any evidence of deletion or gross rearrangement of the Dutt1/Robo1 gene. These results suggest that alterations of the Dutt1/Robo1 gene may be involved in the development of some lung adenocarcinomas induced by BHP in rats. © 2004 Wiley‐Liss, Inc.
Towards an understanding of organic anion transporters: Structure–function relationships
Authors: You Guofeng 
Published: June 2004

AbstractOrganic anion transporters (OAT) play essential roles in the body disposition of clinically important anionic drugs, including anti‐viral drugs, anti‐tumor drugs, antibiotics, anti‐hypertensives, and anti‐inflammatories. The activities of OATs are directly linked to drug toxicity and drug–drug interactions. So far, four members of the OAT family have been identified: OAT1, OAT2, OAT3, and OAT4. These transporters share several common structural features including 12 transmembrane domains, multiple glycosylation sites localized in the first extracellular loop between transmembrane domains 1 and 2, and multiple phosphorylation sites present in the intracellular loop between transmembrane domains 6 and 7, and in the carboxyl terminus. The impact of these structural features on the function of these transporters has just begun to be explored. In the present review, the author will summarize recent progress made from her laboratory as well as from others, on the molecular characterization of the structure–function relationships of OATs, including particular amino acid residues/regions of the transporter protein (“molecular domains”) that potentially determine transport characteristics. © 2004 Wiley Periodicals, Inc. Med Res Rev, 24, No. 6, 762–774, 2004
Construction of albumin multilayer coating onto plasma treated poly(vinyl chloride) via electrostatic self‐assembly
Authors: Ji Jian , Tan Qinggang , Shen Jiacong 
Published: June 2004

AbstractMultilayer films consisting of polyethylenimine (PEI) and albumin were successffully prepared on plasma treated poly(vinyl chloride) (PVC) via electrostatic self‐assembly of the PEI and albumin. The layer‐by‐layer assembly of the PEI/albumin on plasma treated PVC was monitored by contact angle and 125I radiolabeled method. The stability of the mutilayer coating was determined by 125I radiolabeled method. The results revealed that less than 10% albumin was eluted by a phosphate buffered saline (PBS) solution in 45 days. The static platelet adhesion indicated that the PEI/albumin deposited PVC could resist the platelet adhesion effectively. Such an easy processing and shape‐independent method may have good potential for surface modification of cardiovascular device. Copyright © 2004 John Wiley & Sons, Ltd.
Studies on grafting of tris(2‐methoxyethoxy)vinylsilane onto ethylene‐propylene‐diene terpolymer
Authors: Ramar P. , Alagar M. 
Published: June 2004

AbstractNew graft copolymer was prepared by incorporating tris(2‐methoxyethoxy)vinylsilane (TMEVS) on ethylene‐propylene‐diene terpolymer (EPDM) by using dicumyl peroxide (DCP) as initiator, in Haake Rheocord 90 torque rheometer. The effect of EPDM concentration, TMEVS concentration, reaction time, reaction temperature and initiator concentration on the graft co polymerization was studied. The grafting efficiency of TMEVS on EPDM was confirmed by Fourier Transform infrared (FT‐IR) spectroscopy. The grafting efficiency increased with increase in the silane concentration upto 6% by weight. The grafting efficiency decreased beyond 6% by weight due to homopolymerization of TMEVS and non‐availability of carbon–carbon double bond in the EPDM terpolymer. The thermal properties of peroxide cured EPDM and hot water cured EPDM‐g‐TMEVS were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. The results show thermal properties like degradation tempertature and glass transition temperature of the EPDM‐g‐TMEVS were increased due to introduction of TMEVS on to EPDM terpolymer as well as the formation of thermally stable three‐dimensional network. Copyright © 2004 John Wiley & Sons, Ltd.
The mechanical and thermal behaviors of glass bead filled polypropylene
Authors: Yuan Qiang , Jiang Wei , An Lijia , Li R. K. Y. 
Published: June 2004

AbstractNotch Izod impact strength of poly(propylene) (PP)/glass bead blends was studied as a function of temperature. The results indicated that the toughness for various blends could undergo a brittle‐ductile transition (BDT) with increasing temperature. The BDT temperature (TBD) decreased with increasing glass bead content. Introducing the interparticle distance (ID) concept into the study, it was found that the critical interparticle distance (IDc) reduced with increasing test temperature correspondingly. The static tensile tests showed that the Young's modulus of the blends decreased slightly first and thereafter increased with increasing glass bead content. However, the yield stress decreased considerably with the increase in glass bead content. Dynamic mechanical analysis (DMA) measurements revealed that the heat‐deflection temperature of the PP could be much improved by the incorporation of glass beads. Moreover, the glass transition temperature (Tg) increased obviously with increasing glass beads content. Differential scanning calorimetry (DSC) results implied that the addition of glass beads could change the crystallinity as well as the melting temperature of the PP slightly. Thermogravimetric analysis (TGA) measurements implied that the decomposition temperature of the blend could be much improved by the incorporation of glass beads. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of Pluronic F127 on the pore structure of macrocellular biodegradable polylactide foams
Authors: Zhang Rong , Weng Wenjian , Du Piyi , Zhao Gaoling , Shen Ge , Han Gaorong 
Published: June 2004

AbstractThermally induced phase separation technique was utilized to fabricate biodegradable poly(l‐lactic acid) (PLLA) macrocellular foams which were capable of being applied in tissue engineering. The block copolymer Pluronic F127 composed of (polyethyleneoxide)‐(polypropyleneoxide)‐(polyethyleneoxide) [(PEO)‐(PPO)‐(PEO)] was used as a porogen. Water/dioxane mixtures with different volume ratios were used as solvents. The addition of Pluronic F127 could induce an appearance of large pores (50–200 μm) besides small pores (10–20 μm) or a change from a solid–liquid phase separation to a liquid–liquid phase separation. The role of Pluronic F127 depends on the water/dioxane ratios in the PLLA/dioxane/water system. The X‐ray diffraction patterns and porosity measurement results showed that Pluronic F127 was crystallized and existed on the pore wall. The effect of Pluronic F127 on changing pore structure is attributed to the occurrence of the interaction of the lipophilic PPO blocks in Pluronic F127 with PLLA clews, consequently, this results in PLLA aggregation and early phase separation on cooling. Copyright © 2004 John Wiley & Sons, Ltd.
Radiation‐grafted solid polymer electrolyte membrane: studies of fluorinated ethylene propylene (FEP) copolymer‐g‐acrylic acid grafted membranes and their sulfonated derivatives
Authors: Patri M. , Hande V. R. , Phadnis Swati , Deb P. C. 
Published: June 2004

AbstractAcrylic acid was grafted onto FEP by simultaneous radiation technique and the resulting membranes were sulfonated. Results of dynamic mechanical properties of the membranes showed that storage modulus and temperature at tan δ(max) increases on grafting. X‐ray diffraction (XRD) analysis of the grafted and sulfonated membranes showed decreasing trend in crystallinity with increase in degree of grafting. From scanning electron microscopy (SEM) studies it was confirmed that grafting takes place by the front mechanism. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and characteristics of novel chelate fiber containing amine and amidine groups
Authors: Shin Dong Hun , Ko Young Gun , Choi Ung Su , Kim Woo Nyon 
Published: June 2004

AbstractA polyacrylonitrile (PAN) fiber was adopted for the backbone of a chelate polymer and poly(acrylo‐amidino ethylene amine) (PAEA) was prepared through a one‐step reaction between the PAN fiber and ethylenediamine (EDA). The maximum removal capacity and degree of substitution were 7.8 meq per gram of dried PAEA and 98%, respectively. The PAEA was tested as an adsorbent in single and two‐component metal aqueous solutions under changing pH. The Cu2+ ion accomplished maximum adsorption amount at pH 3 and the order of maximum adsorbed amounts on PAEA is Cu2+ > Ag+ > Zn2+ > Ni2+ > Pb2+ in molar basis. FT‐IR spectroscopy was employed to characterize the chemical bonding in metal aqueous solutions and surface morphology was examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Copyright © 2004 John Wiley & Sons, Ltd.
Preparation and characterization of PVC/PANI conductive composite with extremely low percolation threshold
Authors: Wang Yangyong , Jing Xinli 
Published: June 2004

AbstractAniline was polymerized in the presence of poly(vinyl chloride) (PVC) powders in hydrochloric acid to in situ prepare poly(vinyl chloride)/polyaniline (PVC/PANI) composite particles. UV‐vis spectra and FT‐IR spectra indicate PANI in PVC/PANI composite particles possessed a higher oxidation state with decreased aniline content in reactants. Both conductivity and impact strength of the dodecylbenzenesulfonic acid (DBSA) doped PANI composites (PVC/PANI‐DBSA), which were compression molded from the in situ prepared PVC/PANI particles, increase with the pressing temperature and decrease with the increase of DBSA doped PANI (PANI‐DBSA) loading. An excellent electric conductivity of 5.06 × 10−2 S/cm and impact strength of 0.518 KJ/m2 could be achieved for the in situ synthesized and subsequently compression molded composite. Copyright © 2004 John Wiley & Sons, Ltd.
Cancer incidence among adolescents in France
Authors: Desandes Emmanuel , Lacour Brigitte , Sommelet Danièle , Buemi Antoine , Danzon Arlette , Delafosse Patricia , Grosclaude Pascale , Mace‐Lesech Josette , Raverdy‐Bourdon Nicole , Tretarre Brigitte , Velten Michel , Brugieres Laurence 
Published: June 2004

AbstractBackgroundIn France, cancer ranks third as the most significant cause of mortality in young people. However, the incidence, the survival, and the management of adolescent cancers have never been studied. The aim of this study is to investigate incidence rate (IR) of adolescents with cancer from data recorded in French Cancer Registries covering eight administrative areas, representing 10% of the French population, over a 10‐year period (from 1988 to 1997).ProcedureData from the FRANCIM network of French population‐based Cancer Registries were used to analyze cancer incidence among adolescents aged from 15 to 19 years, excluding basal cell carcinomas of skin.ResultsIn total, 699 cases were recorded. Of these, 22.9% were lymphomas, 12.7% germ‐cell tumors, 11.9% leukemias, 10.6% central‐nervous‐system tumors, 10.0% bone neoplasms, 7.6% soft‐tissue sarcomas, and 19.5% tumors of adulthood (thyroid carcinomas 4.9%, melanomas 9.0%, and other carcinomas 5.6%). The overall IR was 172.9 per million adolescents (M/F: 1.2) with an annual increase of 3% (P = 0.58). Over the two 5‐year periods (1988–1992 and 1993–1997) the IR increases significantly for malignant melanomas (respectively 10.4 and 21.2; P = 0.04).ConclusionsOur findings are similar to that reported by previous studies performed in European and North‐American countries. Future studies need to focus on the etiology explaining the increase in incidence, the management and the impact of the type of care on outcomes. © 2004 Wiley‐Liss, Inc.
Outcome in children with pulmonary Langerhans cell histiocytosis
Authors: Braier Jorge , Latella Antonio , Balancini Blanca , Castaños Claudio , Rosso Diego , Chantada Guillermo , Ripoli Mario , Goldberg Julio 
Published: June 2004

AbstractBackgroundThe aim of this study was to evaluate features and outcome of children with Langerhans cell Histiocytosis (LCH) and pulmonary involvement.ProcedureRetrospective evaluation of LCH patients was performed from 1987 to 2001. Multisystem patients were classified according to the pattern of organ system involvement into Groups: A (no pulmonary, hematologic, or hepatic involvement), B (pulmonary involvement), C (pulmonary and hematologic or hepatic involvement), and D (hematologic or hepatic involvement). All had skin, bone, or lymph node involvement. Chest X‐ray was performed in all patients and computed tomography (CT) in 21. Diagnostic lung biopsy was performed in five patients.ResultsPulmonary involvement was found in 36/220 patients studied. Two patients had isolated pulmonary involvement. Multisystem involvement was present in 83 patients, 34 of whom had pulmonary involvement. In 20/36 patients, tachypnea, cough, and thoracic pain occurred. Diffuse interstitial involvement was found in all cases. Pulmonary function tests were performed in nine patients, six of whom revealed mild to moderate restrictive respiratory involvement. The two patients having isolated pulmonary involvement survived 2 and 2.7 years after diagnosis. Median follow‐up of all multisystem patients was 2.1 years, with a 5‐year survival probability of 0.59. The 5‐year survival probability of Groups A–D was 0.94, 0.83, 0.23, and 0.40, respectively. The survival difference between Groups B and C was statistically different (P < 0.0071).ConclusionsAccording to our data, pulmonary compromise without other risk organ involvement does not appear to be a negative prognostic factor in our study. © 2004 Wiley‐Liss, Inc.
Hepatoblastoma in a girl with biliary atresia: Coincidence or co‐incidence
Authors: Taat F. , Bosman D.K. , Aronson D.C. 
Published: June 2004

AbstractHepatoblastoma (HB) and biliary atresia (BA) are both rare conditions that occurred in the patient described. This is the second such case in the literature. An explanation for this apparent coincidence could possibly be found in the existance of pluripotent liver stem cells. In humans, small epithelial cells (SEC) behave as pluripotent stem cells. These are cells that can develop as biliary epithelial cells or as liver parenchymal cells, and are thought to be the precursor cell of HB. They are present in a much higher concentration in the livers of patients with BA, which may make them prone to develop HB. © 2004 Wiley‐Liss, Inc.
Outcome of children with B cell lymphoma in Venezuela with the LMB‐89 protocol
Authors: Acquatella G. , Insausti C.L. , García R. , Gómez R. , Hernández M. , Carneiro M. , Santos S. , Nouel A. 
Published: June 2004

AbstractBackgroundWe analyzed the results of the LMB‐89 protocol performed in seven centers in Venezuela in 96 children having B‐cell non‐Hodgkin lymphoma treated from 1995 to 2002.ProcedureMean age was 7.1 years with 71 (74%) been male. Eighty‐two patients (85%) had diffuse small cell lymphoma Burkitt and Burkitt‐like, and 14 (15%) had diffuse large B‐cell lymphoma. Initial disease sites included the abdomen in 67%, peripheral nodes in 8%, and mediastinal in 4%. Treatment was directed to risk groups as described for LMB‐89 protocol. Group A: seven patients (7%), group B: 80 patients (83%), and group C: nine patients (9%).ResultsMean follow‐up was 35 ± 31 months. Complete remission (CR) occurred in 70 patients (73%); four patients (6%) had relapse during the first year and ten patients (10%) had progressive disease. Overall survival (OS) and event free survival (EFS) were 85 and 80% at 1 year, and 82 and 75% at 2 years, respectively. The EFS by therapeutic groups at 3 years was A: 100%; B: 76%, and C: 56%. Toxicity: neutropenia in 75%, thrombocytopenia in 63%, febrile neutropenia in 39%. Viral infections: hepatitis B in 20%, hepatitis C in 2%, and Herpes zoster in 3%. Tumor lysis syndrome (TLS) occurred in 9% during induction phase with a high mortality of 44% (urate‐oxidase was available only at the end of the study).ConclusionsThe high mortality rate during induction phase prohibited a better EFS. Prophylactic use of xantine‐oxidase may improve future results. The high incidence of hepatitis B requires a vaccination program. © 2004 Wiley‐Liss, Inc.
The value of postoperative radiotherapy in childhood nonrhabdomyosarcoma soft tissue sarcoma
Authors: Paulino Arnold C. , Ritchie Justine , Wen B‐Chen 
Published: June 2004

AbstractObjectiveTo determine the value of postoperative radiotherapy (RT) in the management of nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) of childhood.ProcedureFrom 1964 to 2000, 62 children with a median age of 14 years were seen at the University of Iowa and underwent a wide local excision for non‐metastatic NRSTS. Tumors were high grade in 36 (58%) and >5 cm in 24 (39%). Margins of resection were negative (Group I) in 37 (60%) and positive (Group II) in 25 (40%). Postoperative RT was delivered to 20 patients (32%); eight of 37 (22%) Group I and 12 of 25 (48%) Group II children received postoperative RT. Chemotherapy was employed in 19 patients (31%). Median follow‐up was 9.6 years.ResultsThe 5‐ and 10‐year overall survival rates for Group I were 69 and 63% and for Group II were 66 and 60%. The 5‐ and 10‐year local control rate was 66%. On multivariate analysis, size of tumor (P < 0.001) and postoperative RT (P = 0.017) were prognostic factors for local control. All 13 Group I children with low grade, ≤5 cm tumors were locally controlled without RT. For Group II patients, 2‐ and 5‐year local control rates were 92 and 82% with postoperative RT and 51 and 43% for no RT (P = 0.0426).ConclusionsLocal control was improved by the addition of postoperative RT in tumors with positive margins of resection. © 2004 Wiley‐Liss, Inc.