bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship between genetic alterations and prognosis in sporadic colorectal cancer
Authors: Chang Shih‐Ching , Lin Jen‐Kou , Yang Shung Haur , Wang Huann‐Sheng , Li Anna Fen‐Yau , Chi Chin‐Wen 
Published: October 2005

AbstractBecause chromosomal chromosomal instability (CIN) and microsatellite instability (MSI) are important genetic alterations in colorectal cancers, we classified the sporadic colorectal cancers (CRC) on the status of the CIN and MSI and explored their molecular profiles. A total of 213 colorectal tumors were collected for analysis of DNA ploidy, MSI, loss of heterozygosity (LOH), mutation of p53 (exons 5 to 9), Ki‐ras (exons 1 and 2) and BRAF (V599E). Relationships between clinicopathological variables and molecular analyses were analyzed with the χ2 test (Yates' correction). Kaplan–Meier survival curves were compared using log‐rank test. Variables with p < 0.1 were entered into the Cox regression hazard model for multivariate analysis. High microsatellite instability (MSI‐H) existed in 19 tumors (8.9%), which were more likely to be right‐sided (31.6%) with poor differentiation (26.3%). Seventy‐one (33.3%) tumors were diploid and 142 (66.7%) were aneuploid. Mutations in p53, Ki‐ras and BRAF were found in 45.1%, 41.8% and 4.2% of tumors, respectively. Based on MSI, and CIN, 3 classes were defined: (i) High microsatellite instability MSI‐H tumors: young age, high carcinoembryonic antigen (CEA) level, right colon, poorly differentiated, mucin production, high BRAF mutation, lower allelic loss and relatively good prognosis; (ii) Microsatellite stability (MSS) diploid tumors: right colon, poorly differentiated, less infiltrative tumor, mucin production, lower allelic loss and low p53, BRAF mutation; (iii) MSS aneuploid tumors: more infiltrative invasion, greater allelic loss and high p53 mutation. According to multivariate analysis, tumor stage and p53 mutation were significantly associated with disease progression. The MSS diploid and MSS aneuploid CRCs could be subtyped with p53 mutation and had different prognostic outcome and molecular profiles. The 4‐year disease‐free survival (DFS) of patients with MSS‐diploid, wild‐type p53 tumors was 67% and significantly higher than those of patients with MSS‐diploid, mutant p53 CRC (30%, p = 0.003). The same trend was found in patients with MSS‐aneuploid CRC(wild p53 vs. mutant p53, 64% vs. 41%, p = 0.009). We concluded that CIN, MSI and p53 mutation status might be used as a multiple parameter profile for the prognosis of sporadic colorectal cancer. © 2005 Wiley‐Liss, Inc.
Expression of a thioredoxin‐related protein‐1 is induced by prostaglandin E2
Authors: Kim Kye Young , Lee June Woo , Park Min Seon , Jung Myeong Ho , Jeon Gyoung A , Nam Myeong Jin 
Published: October 2005

AbstractProstaglandin E2 (PGE2) plays an important role in protection of the gastric mucosa against various damaging agents and growth‐inhibitory activity on tumor cells. However, the precise regulation mechanism of PGE2 in gastric cancer cells is still unclear. In this study, we isolated a gene, which is regulated by PGE2 in SNU‐1, human gastric adenocarcinoma cells, using differential display RT‐PCR (DD RT‐PCR) and characterized the function of the gene induced by PGE2. The full‐length cDNA of the gene was cloned by the rapid amplification of cDNA ends method. The 1659 base pair cDNA consists of a 30‐nt 5′‐noncoding region, an 891‐nt open reading frame and a 738‐nt 3′noncoding region that includes a poly (A) signal. As a result of protein motif search, we found that it has a conserved thioredoxin‐active site, Cys‐Gly‐Pro‐Cys and a Myb‐DNA binding domain repeat signature. Thus, we designated this gene product as thioredoxin‐related protein‐1, TRP‐1. TRP‐1 was expressed in a lower extent in renal, gastric and colon cancer tissues and is translated into 33 kDa protein in nuclear and cytoplasmic fractions. TRP‐1 has a thioredoxin activity, which was detected using the insulin disulfide reduction assay. Another potential role of TRP‐1 is repression of B‐Myb activity through direct binding to B‐Myb, a transcriptional factor induced at G1–S transition. Finally, TRP‐1 overexpression inhibits mammalian cell proliferation and specifically predispose to G0/G1 phase arrest. In conclusion, these results imply that TRP‐1 is a mammalian thioredoxin and plays as a transcriptional repressor through direct binding to the transcription factor B‐Myb. © 2005 Wiley‐Liss, Inc.
Long‐Chain Branching and Rheological Properties of Ethylene‐1‐Hexene Copolymers Synthesized from Ethylene Stock by Concurrent Tandem Catalysis
Authors: Ye Zhibin , AlObaidi Fahad , Zhu Shiping , Subramanian Ramesh 
Published: October 2005

AbstractSummary: Concurrent tandem catalysis systems have shown a significant advantage in the convenient synthesis of linear low‐density polyethylene (LLDPE) from a sole ethylene monomer stock by uniquely coupling the tandem action between an ethylene oligomerization catalyst and an ethylene copolymerization catalyst in a single reactor. Recently, we have reported the successful synthesis of ethylene‐hexene derived LLDPE using an effective concurrent tandem catalysis system comprising (η5‐C5H4CMe2C6H5)TiCl3 (1)/MMAO and a CGC copolymerization catalyst, [(η5‐C5Me4)SiMe2(tBuN)]TiCl2 (2)/MMAO. In this work, we report the results from an extensive study on the important rheological properties of LLDPE grades prepared with this tandem catalysis system. Two sets of LLDPE samples having different short‐chain branching density (SCBD) were prepared with the tandem catalysis system under various catalyst concentrations and at temperatures of 25 and 45 °C. The melt rheological properties of these polymers were evaluated using small‐amplitude dynamic oscillation measurements. These polymers have been found to possess typical rheological properties found in long‐chain branched (LCB) polymers, such as enhanced zero‐shear viscosity (η0), improved shear‐thinning, elevated dynamic moduli, and thermorheological complexity, which indicate the presence of long‐chain branching in the polymers. The long‐chain branching density (LCBD) of the two respective sets of polymers were qualitatively compared and correlated to the polymerization conditions including catalyst ratio and temperature. This work represents the first study on the rheological properties of LLDPE synthesized with concurrent tandem catalysis, and it discloses another appealing feature of this unique approach—its ability to produce LCB LLDPE from a single ethylene monomer stock.Synthesis of linear low‐density polyethylene (LLDPE) from ethylene using ethylene oligomerization catalyst and an ethylene copolymerization catalyst.magnified imageSynthesis of linear low‐density polyethylene (LLDPE) from ethylene using ethylene oligomerization catalyst and an ethylene copolymerization catalyst.
Neutral Polymeric Surfactants Derived from Dextran: A Study of Their Aqueous Solution Behavior
Authors: Rotureau Elise , Chassenieux Christophe , Dellacherie Edith , Durand Alain 
Published: October 2005

AbstractSummary: Amphiphilic polysaccharides are obtained by hydrophobic modification of a neutral bacterial polysaccharide, dextran. By reacting the polysaccharide with aliphatic epoxides (epoxyoctane and epoxydodecane) in dimethyl sulfoxide, a series of amphiphilic polymers is obtained which covers a large range of structural parameters (length of the polysaccharide, number and nature of hydrocarbon moieties). The solution behavior of dextran derivatives is first characterized by viscometric measurements in dilute and semi‐dilute domains. The effects of molecular parameters on polymer viscosity behavior are evidenced and discussed. Information on the state of aggregation of polymers is obtained by the use of static and dynamic light scattering. The presence of aggregates in the dilute domain is clearly evidenced and their structural characteristics are estimated (size, molecular weight and number of aggregation). The aggregates are shown to account for the viscometric results in the examined concentration range, relating their chemical parameters (hydrodynamic radius and molecular weight) to the macroscopic behavior of the solutions.
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Study of the Fragmentation Process of Different Supports for Metallocenes by Laser Scanning Confocal Fluorescence Microscopy (LSCFM)
Authors: Jang Yong‐Jun , Naundorf Corinna , Klapper Markus , Müllen Klaus 
Published: October 2005

AbstractSummary:The fragmentation of supports, a key issue for the polymerization of olefins via supported metallocene catalysts, was investigated by laser scanning confocal fluorescence microscopy (LSCFM). Metallocenes were immobilized on silica and on two organic supports, namely polystyrene latex particles and a polystyrene resin, which were stained by fluorescent perylene dyes. All supported catalysts showed different activities in the ethylene polymerization under the same reaction conditions. Recording fluorescence images of the polyolefin product beads at different polymerization times by LCSFM proved different fragmentation processes for the catalyst. While for the µm‐sized polystyrene resins almost no fragmentation was observed, supports based on aggregated latex particles fragmented throughout the bead from the beginning, corresponding to the multi‐grain model established for Ziegler‐catalysts. For the silica particles a fragmentation starting from the outer spheres to the core was detected, confirming in a fast and easy way the layer‐by‐layer model developed by electron microscopy studies.SEM images of the catalyst supported on (A) microsized PS beads, (B) nanosized PS beads and (C) silica gel.magnified imageSEM images of the catalyst supported on (A) microsized PS beads, (B) nanosized PS beads and (C) silica gel.
Core Functionality and Scaling Behavior of Lysine Dendrimers
Authors: Fritzinger Bernd , Appelhans Dietmar , Voit Brigitte , Scheler Ulrich 
Published: October 2005

AbstractSummary: A scaling exponent to describe the dependence of the hydrodynamic radius as a characteristic length of the molecule on the molecular weight, has been determined for low generation dendrimers with a thiacalixarene core and lysine dendrons. The hydrodynamic radius has been calculated from the diffusion coefficient measured by pulsed‐field‐gradient NMR spectroscopy. Scaling exponents of 2.0 for the lysine monodendron, 2.3 for a dendrimer with a bifunctional core, and 3.9 for a dendrimer with a tetrafunctional core have been determined. For a given structure of the dendrons, the scaling exponent reflects the functionality of the core of the dendrimers.Hydrodynamic radius of lysine dendrons as a function of molar mass.imageHydrodynamic radius of lysine dendrons as a function of molar mass.
Fabrication of Electrically Conducting Polypyrrole‐Poly(ethylene oxide) Composite Nanofibers
Authors: Nair Sujith , Natarajan Sudarshan , Kim Seong H. 
Published: October 2005

AbstractSummary: Electrically conducting polypyrrole‐poly(ethylene oxide) (PPy‐PEO) composite nanofibers are fabricated via a two‐step process. First, FeCl3‐containing PEO nanofibers are produced by electrospinning. Second, the PEO‐FeCl3 electrospun fibers are exposed to pyrrole vapor for the synthesis of polypyrrole. The vapor phase polymerization occurs through the diffusion of pyrrole monomer into the nanofibers. The collected non‐woven fiber mat is composed of 96 ± 30 nm diameter PPy‐PEO nanofibers. FT‐IR, XPS, and conductivity measurements confirm polypyrrole synthesis in the nanofiber.An SEM image of the PPy‐PEO composite nanofibers. The scale bar in the image is 500 nm.imageAn SEM image of the PPy‐PEO composite nanofibers. The scale bar in the image is 500 nm.
A New Poly(fluorene‐co‐carbazole) with a Large Substituent Group at the 9‐Position of the Carbazole Moiety: An Efficient Blue Emitter
Authors: Du Junping , Fang Qiang , Bu Dongsheng , Ren Shijie , Cao Amin , Chen Xiaoyao 
Published: October 2005

AbstractSummary: A new poly(fluorene‐co‐carbazole) (PFC‐1) with a large substituent group (ADN, a naphthalene‐anthracene derivative moiety) at the 9‐position of carbazole was synthesized. Compared with poly(fluorene‐co‐carbazole)s that have an alkyl substituent group at the 9‐position of the carbazole, the UV‐vis absorption (or photoluminescent emission) peaks of PFC‐1 are in almost the same position both in solution and in the solid state, whereas films of the former give peaks at longer wavelengths than those in solution. The photoluminescent (PL) spectra of PFC‐1 indicate that the attachment of ADN to the poly(fluorene‐co‐carbazole)s gives rise to an efficient blue emission from non‐aggregated ADN. There is no difference evident between PFC‐1 and other reported poly(fluorene‐co‐carbazole)s in PL quantum yield, thermostability, and electrochemical behavior, which suggests that PFC‐1 is an efficient blue emitter.UV‐Vis spectra of the poly(fluorene‐co‐carbazole) (PFC‐1), with a large substituent group (ADN, a naphthalene‐anthracene derivative moiety) at the 9‐position of carbazole, in toluene and in the film.imageUV‐Vis spectra of the poly(fluorene‐co‐carbazole) (PFC‐1), with a large substituent group (ADN, a naphthalene‐anthracene derivative moiety) at the 9‐position of carbazole, in toluene and in the film.
Novel Amphiphilic Diblock and Triblock Liquid‐Crystalline Copolymers with Well‐Defined Structures Prepared by Atom Transfer Radical Polymerization
Authors: Yu Haifeng , Shishido Atsushi , Ikeda Tomiki , Iyoda Tomokazu 
Published: October 2005

AbstractSummary: Based on a hydrophilic poly(ethylene oxide) macroinitiator (PEOBr), a novel amphiphilic diblock copolymer PEO‐block‐poly(11‐(4‐cyanobiphenyloxy)undecyl) methacrylate) (PEO‐b‐PMA(11CB)) was prepared by atom transfer radical polymerization (ATRP) using CuCl/1,1,4,7,10,10‐hexamethyltriethylenetriamine as a catalyst system. An azobenzene block of poly(11‐[4‐(4‐butylphenylazo)phenoxyl]undecyl methacrylate) was then introduced into the copolymer sequence by a second ATRP to synthesize the corresponding triblock copolymer PEO‐b‐PMA(11CB)‐b‐PMA(11Az). Both of the amphiphilic block copolymers had well‐defined structures and narrow molecular‐weight distributions, and exhibited a smectic liquid‐crystalline phase over a wide temperature range.The amphiphilic triblock copolymer synthesized here.imageThe amphiphilic triblock copolymer synthesized here.
Entropic Sampling of Free and Ring Polymer Chains
Authors: Volkov Nikolai A. , Yurchenko Anton A. , Lyubartsev Alexander P. , Vorontsov‐Velyaminov Pavel N. 
Published: October 2005

AbstractSummary: We extend Monte Carlo (MC) methods developed in our previous paper (J. Phys. A, Math. Gen. 2004, 37, 1573) and based on entropic sampling within Wang‐Landau (WL) algorithm to the simulation of lattice and continuous models of ring polymers. For a continuous freely joined ring chain (an equilateral polygon) with hard sphere monomer units, the excess entropy of rings relative to the corresponding reference system, a phantom ring chain, is obtained. The excess specific entropy is calculated for a set of various diameters of monomer units d and chain lengths N. Its limiting values for $N\to \infty$ ($N^{-1}\to 0$) are estimated for each d and coincidence with those for corresponding free chains is demonstrated. We also develop a WL approach to calculate thermal properties of free and ring continuous chains with an Lennard‐Jones attraction between nonbonded beads being added to hard core repulsion at fixed d. The obtained energy distributions provide calculation of canonical properties such as conformational energy, heat capacity, entropy, and mean square radius of inertia. Thermal results for free and ring chains are being finally compared. Analogous calculations are performed for lattice‐free chains and rings.
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Weighted Poincaré and Korn inequalities for Hölder α domains
Authors: Acosta Gabriel , Durán Ricardo G. , Lombardi Ariel L. 
Published: October 2005

AbstractIt is known that the classic Korn inequality is not valid for Hölder α domains. In this paper, we prove a family of weaker inequalities for this kind of domains, replacing the standard Lp‐norms by weighted norms where the weights are powers of the distance to the boundary.In order to obtain these results we prove first some weighted Poincaré inequalities and then, generalizing an argument of Kondratiev and Oleinik, we show that weighted Korn inequalities can be derived from them.The Poincaré type inequalities proved here improve previously known results.We show by means of examples that our results are optimal. Copyright © 2005 John Wiley & Sons, Ltd.
Visualization of material stiffness in geomechanics analysis
Authors: Wotring Donald C. , Hashash Youssef M. A. 
Published: October 2005

AbstractThis paper presents novel visualization techniques to simplify representation of the fourth‐order material stiffness tensor as a set of three‐dimensional geometric objects. Stiffness visualization aids in understanding the complex stiffness characteristics of highly non‐linear constitutive models including modelled material anisotropy and loading path dependent stiffness variation. Stiffness visualization is relevant for understanding the relationship of material stiffness to global behaviour in the analysis of a boundary value problem. The spherical pulse stiffness visualization method, developed in the acoustics field, is extended to visualize stiffness of geomaterials using three three‐dimensional objects. This method is limited to relatively simple constitutive models with symmetric stiffness matrices insensitive to loading magnitude and direction. A strain dependent stiffness visualization method is developed that allows the examination of material stiffness for a range of loading directions and is suitable for highly non‐linear and path dependent material models. The proposed stiffness visualization can be represented as 3‐D, 2‐D and 1‐D objects. The visualization technique is used to represent material stiffness and its evolution during simulated soil laboratory tests and deep excavation construction. Copyright © 2005 John Wiley & Sons, Ltd.
Catalytic dehydrogenation of ethane over mononuclear Cr(III)–silica surface sites. Part 2: CH activation by oxidative addition
Authors: Lillehaug Sindre , Jensen Vidar R. , Børve Knut J. 
Published: October 2005

AbstractModels of Cr(III)–silica were used to study CH activation in ethane by oxidative addition as a possible route to catalytic dehydrogenation. This mechanism involves a formal double oxidation of chromium and a minimum energy crossing point (MECP) was located on the seam between the quartet spin potential energy surface of Cr(III) and the doublet spin potential energy surface of Cr(V). Subsequent to the change of spin state, the CH activation path passes through a transition state on the doublet potential surface, leading to the formation of an ethylhydridochromium(V) complex. This complex represents only a shallow minimum on the potential energy surface and β‐hydrogen transfer to complete the catalytic cycle must therefore take place in the extension of the CH activation step. The combination of a significant activation energy and a small pre‐exponential factor in the rate constant makes CH activation by oxidative addition an unlikely mechanism for dehydrogenation in this system. Copyright © 2005 John Wiley & Sons, Ltd.
Star‐shaped poly(L‐lactide)s with variable numbers of hydroxyl groups at polyester arms chain‐ends and directly attached to the star‐shaped core—Controlled synthesis and characterization
Authors: Biela Tadeusz , Duda Andrzej , Pasch Harald , Rode Karsten 
Published: October 2005

AbstractStar‐shaped poly(L‐lactide)s (PLAs) bearing variable numbers of secondary hydroxyl groups at linear arms chain‐ends and primary hydroxyl groups directly attached to dipentaerithritol core (DPE) ((HO)6−xDPE(PLA‐OH)x, where x = 1–6) were prepared and then analyzed by means of size exclusion chromatography (SEC), 1H NMR spectroscopy, MALDI‐TOF mass spectrometry, and eventually by Liquid Chromatography at Critical Conditions (LC‐CC). First, starting from DPE(OH)6 a series of polyols with various number of hydroxyl groups has been obtained ((BnO)6−xDPE(OH)x, where Bn denotes benzyl moiety and x = 1–6). The living ring‐opening polymerization of L‐lactide (LA) with (BnO)6−xDPE(OH)x/tin(II) octoate mixtures as initiating and catalytic system led to star‐shaped (BnO)6−xDPE(PLA‐OH)x polymers with molar masses (Mn) controlled by LA and DPE concentrations ratio in the feed. Finally, deprotection (via hydrogenation) gave a series of (HO)6−xDPE(PLA‐OH)x PLA's. SEC (with Multiangle Laser Light Scattering Detector (MALLS)), NMR, and MALDI‐TOF analyses confirmed the assumed structures and Mn's of the prepared (BnO)6−xDPE(PLA‐OH)x and (HO)6−xDPE(PLA‐OH)x PLA's. LC‐CC measurements revealed that for (BnO)6−xDPE (PLA‐OH)x series the elution volumes increase monotonically with the increasing number of –PLA‐OH arms in one macromolecule and are independent on the given PLA molar mass because of the critical conditions. Contrary to the polymers having the protected core hydroxyl groups, the elution volume for (HO)6−xDPE(PLA‐OH)x series decreases with the increasing number of ‐PLA‐OH arms reaching a minimum value for 4‐arm PLA and then slightly increases for 5‐ and 6‐arm PLA. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6116–6133, 2005
Studies on the modification of poly(ω‐bromoalkyl‐1‐glycidylether)s with 4′‐methoxybiphenyl‐4‐oxy mesogenic groups
Authors: Montornés J. M. , Reina J. A. , Ronda J. C. 
Published: October 2005

AbstractA series of poly[ω‐(4′‐methoxy‐biphenyl‐4‐oxy)alkyl‐1‐glycidylether]s were synthesized by chemically modifying the corresponding poly(ω‐bromoalkyl‐1‐glycidylether)s with the sodium salt of 4‐hydroxy‐4′‐methoxybiphenyl. New high‐molecular‐weight side‐chain liquid‐crystalline polymers were obtained with excellent yields and almost quantitative degrees of modification. They were all insoluble in THF and other common solvents. Characterization by 13C NMR confirmed that all the polymers had the expected structure. The liquid crystalline behavior of the polymers was analyzed by DSC and polarized optical microscopy, and mesophase assignments were confirmed by X‐ray diffraction studies. Polymers that had alkyl spacers with n = 2 and 4 were smectic C, those that had spacers with n = 6 and 8 were nematic cybotactic, and those that had longer spacers (n = 10 and 12) were smectic C again. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5998–6006, 2005
Synthesis and crosslinking reaction of poly(hydroxyurethane) bearing a secondary amine structure in the main chain
Authors: Ochiai Bungo , Nakayama Jun‐ichi , Mashiko Masayuki , Kaneko Yoshiro , Nagasawa Tomomi , Endo Takeshi 
Published: October 2005

AbstractThis article describes the polyaddition of bifunctional five‐membered cyclic carbonates and diethylenetriamine. The polyaddition proceeded via the selective addition of the primary amino group to the cyclic carbonates to give poly(hydroxyurethane)s bearing a secondary amine structure in the main chain. The resulting poly (hydroxyurethane) having a secondary amine structure was crosslinked by a reaction with a bifunctional dithiocarbonate to give a networked poly(hydroxyurethane–mercaptothiourethane). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5899–5905, 2005