bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Thermosensitive PNIPAm‐Grafted Mesoporous Silica Particles
Authors: Park Jun‐Hwan , Lee Young‐Ho , Oh Seong‐Geun 
Published: September 2007

AbstractIn this study, the composites of thermoresponsive poly(N‐isopropylacrylamide) (PNIPAm) and mesoporous silica particles were synthesized. 3‐(Trimethoxysilyl)propyl methacrylate (MOP) was used to introduce double bonds on silica particles. First, MOP‐modified spherical silica particles were prepared by the sequential addition of tetraethyl orthosilicate (TEOS) and MOP into W/O (water‐in‐oil) emulsion. Second, PNIPAm‐grafted silica microparticles were synthesized by the radical copolymerization of MOP‐modified silica particles and N‐isopropylacrylamide (NIPAm) monomers in the ethanol/water mixture. Polymerization was carried out with the variation of reaction temperature, concentration of crosslinking agent, and weight ratio of MOP‐modified silica particles to NIPAm monomers. The formations of MOP‐functionalized silica microspheres and PNIPAm‐grafted silica microparticles were characterized by FE‐SEM, TEM, FT‐IR, TGA, and BET. The lower critical solution temperature (LCST) of the PNIPAm‐grafted silica particles was investigated by DSC.magnified image
Multicyclic Poly(ether ester)s by Polycondensation of Ethoxylated Pentaerythritol with Dicarboxylic Acid Dichlorides
Authors: Kricheldorf Hans R. , Bornhorst Kirstin , Schwarz Gert 
Published: September 2007

AbstractCommercial ethoxylated pentaerythritol (EPE) was polycondensed with phthaloyl chloride, isophthaloylchloride, terephthaloyl chloride, and sebacoyl chloride. The monomer concentration was varied to find the borderline between soluble multicylic polyesters and gelation. The tendency of gelation increased in the above given order of dicarboxylic acids. Gelation was also favored by a lower content of ethylene oxide units in the EPE. An alternative approach based on the cyclization of EPEs with dibutyltin dimethoxide followed by acylation with dicarboxylic acid dichloride proved to be unsuccessful. The soluble multicycles were characterized by 1H NMR spectroscopy, MALDI‐TOF mass spectrometry, viscosity, and SEC measurements. The DSC measurements confirmed an amorphous character of all polyesters.magnified image
Effect of Organoclay on the Orientation and Thermal Properties of Liquid‐Crystalline
Authors: Bandyopadhyay Jayita , Sinha Ray Suprakas , Bousmina Mosto 
Published: September 2007

AbstractThe preparation and thermal and thermo‐mechanical properties of nanocomposites based on liquid‐crystalline polymers (LCP) and organically‐modified layered silicate (OMLS) is described. From XRD patterns, very little smectic ordering is present in the pure LCP; in the nanocomposites, the polymer chains tended to orient in the direction of the dispersed clay layers. According to the DSC results, during first heating, the first melting peak represents the crystalline to nematic transition and, after that, a broader isotropization takes place. Although TGA of the samples showed a single‐step decomposition through chain scission under an inert atmosphere, in air the nanocomposites underwent a two‐step process, with onset of degradation at a higher temperature. The first step is mainly due to chain scission and the second is due to oxidative reactions.magnified image
Structure and Mechanical Properties of Directly Injection‐Molded Blends of Poly(ether imide) and Polysulfone of Bisphenol A
Authors: Ramiro Jorge , Eguiazábal José Ignacio , Nazábal Jon 
Published: September 2007

AbstractBlends of PEI with PSU were prepared directly during the plasticization step of an injection molding process. The phase behavior, the morphology and the mechanical properties of the blends were determined. The blends were composed of an almost pure PEI phase and a PSU‐rich phase. The particle size was very small, indicating a low interphase tension that is attributed to the presence of PEI in the two phases of the blends. The modulus of elasticity of the blends was close to that of the additive. The impact strength was higher than that of PEI. The tensile strength and elongation at break were also almost additive, despite the biphasic nature of the blends, indicating the existence of good interfacial adhesion.magnified image
Fabrication, Morphology and Properties of Soybean Oil‐Based Composites Reinforced with Continuous Glass Fibers
Authors: Lu Yongshang , Larock Richard C. 
Published: September 2007

AbstractNovel thermosetting composites were successfully prepared using glass fiber as a reinforcement for soybean and LoSatSoy oil‐based resins prepared by cationic copolymerization with styrene and divinylbenzene. The effect of the matrix composition and glass fiber loading on the morphology, thermal stability and mechanical properties of the resulting composites were extensively investigated. Increasing the glass fiber loading from 0 to 50 wt.‐% in the composites resulted in a significant increase in Young's modulus from 150 to 2 730 MPa and ultimate tensile strength from 7.9 to 76 MPa. The correlation between the experimental mechanical properties of glass fiber reinforced composites with values calculated by various empirical models was also analyzed. Increasing the crosslinking of the matrix resulted in composites with improved thermal and mechanical properties. These soybean oil‐based composites have good structure damping properties and potential applications where the reduction of both unwanted noise and vibration is important.magnified image
Functional Polymer‐Opals from Core–Shell Colloids
Authors: Lange Birger , Metz Nadine , Tahir Muhammad Nawaz , Fleischhaker Friederike , Theato Patrick , Schröder Heinz‐Christoph , Müller Werner E. G. , Tremel Wolfgang , Zentel Rudolf 
Published: September 2007

AbstractColloidal photonic crystals were prepared from monodisperse core–shell particles. The shell is hereby formed from a functional monomer, such as glycidylmethacrylate or different reactive ester monomers, which can perform chemical reactions and the core from a standard monomer, which yields highly monodisperse colloids. It was possible to crystallize the core–shell particles into artificial opals with excellent optical properties. Reactions on the functional surface of the colloids were carried out, which lead to a dramatic rise in the mechanical stability or to a functionalization of His‐tagged silicatein, which acts as nanoreactor to synthesize and immobilize gold nanoparticles from auric acid onto the core–shell colloids.magnified image
Poly(azomethine) Rotaxanes: Novel Water Soluble Supramolecular Polymers with High Molar Mass
Authors: Horvath Gabriela , Nepal Dhriti , Geckeler Kurt E. 
Published: September 2007

AbstractA novel type of supramolecular poly(azomethine) was synthesized by the polycondensation of an inclusion complex of β‐cyclodextrin/poly(oxypropylene)diamine with one of β‐cyclodextrin/terephthaldehyde and a subsequent reaction with [60]fullerene as the end capping agent. Molar mass determination by gel permeation chromatography showed that the polymers had a high molar mass (about 150 kg · mol−1) with a very narrow polydispersity. Isothermal titration calorimetric studies confirmed that each poly‐(oxypropylene)diamine unit could host seven cyclodextrin molecules, which was further supported by 1H NMR spectroscopy and molecular modeling studies. Additional characterization by 13C NMR and FT‐IR spectroscopy, as well as by thermogravimetric analysis, confirmed the structure of the cyclodextrin‐based polyrotaxane.magnified image
Photocrosslinkable Liquid Crystal Main‐Chain Polymers: Thin Films and Electrospinning
Authors: Krause Simon , Dersch Roland , Wendorff Joachim H. , Finkelmann Heino 
Published: September 2007

AbstractFor mechanical actuators, a response to external stimuli is required. Main‐chain liquid crystal elastomers (MCLCEs) show high response to changes in temperature especially in the vicinity of a phase transition. Most of these crosslinked materials were synthesized in a one‐step reaction which leads to a macroscopically aligned elastomer. Up to now only macroscopic samples have been prepared. We are presenting a new approach which allows us to prepare thin films as well as aligned fibers. First a liquid crystalline main‐chain polymer with a photoactive moiety was synthesized, which was oriented by a mechanical field and photocrosslinked. The thin films show exceptional mechanical properties such as large temperature‐dependent changes in length and a nonlinear stress–strain relation. To obtain fibers, we used the electrospinning process from solution with in situ UV curing. We obtained crosslinked fibers with a uniform alignment of the nematic director.magnified image
Preparation of New Multiarmed RAFT Agents for the Mediation of Vinyl Acetate Polymerization
Authors: Fleet Reda , McLeary J. B. , Grumel V. , Weber W. G. , Matahwa H. , Sanderson R. D. 
Published: September 2007

AbstractSummary: In this study five xanthate (Reversible Addition‐Fragmentation chain Transfer (RAFT)/Macromolecular Design through Interchange of Xanthates (MADIX)) agents were synthesized, namely monofunctional, difunctional, trifunctional and tetrafunctional species of the form SC(O‐Z)‐S‐R, with different leaving groups and different activating moieties some of which are completely novel. Polyvinyl acetates (PVAc) in the form of linear, three armed and four armed star shaped polymers were then successfully synthesized in reactions mediated by these xanthate RAFT/MADIX agents.
Reduced expression of the Rassf1a gene and its aberrant DNA methylation in pancreatic duct adenocarcinomas induced by N‐nitrosobis(2‐oxopropyl)amine in hamsters
Authors: Shimizu Kyoko , Itsuzaki Yumi , Fujii Hiromasa , Honoki Kanya , Tsujiuchi Toshifumi 
Published: September 2007

AbstractAlterations of the Rassf1a gene were investigated in pancreatic duct adenocarcinomas (PDAs) induced by N‐nitrosobis(2‐oxopropyl)amine (BOP) in hamsters. Female Syrian golden hamsters received 70 mg/kg BOP, followed by repeated exposures to an augmentation pressure regimen consisting of a choline‐deficient diet combined with a sequential course of DL‐ethionine, L‐methionine, and 20 mg/kg BOP. A total of 15 PDAs were obtained, and total RNAs were assessed by real‐time quantitative reverse transcription (RT)‐polymerase chain reaction (PCR). Expression of the Rassf1a was significantly reduced in PDAs (P < 0.005) compared with normal pancreatic tissues. For analysis of methylation status, bisulfite sequencing was performed. Normal tissues were all unmethylated in the 5′ upstream region of Rassf1a. In contrast, four PDAs were highly methylated, correlating with reduced expression of the Rassf1a gene. Using reverse transcription (RT)‐polymerase chain reaction (PCR)‐single strand conformation polymorphism (SSCP) analysis, mutations were detected in 3 out of 15 PDAs (20%). These results suggested that alterations of the Rassf1a gene may be involved in development of PDAs induced by BOP in hamsters. © 2007 Wiley‐Liss, Inc.
Independent activation of Akt and NF‐kappaB pathways and their role in resistance to TNF‐α mediated cytotoxicity in gliomas
Authors: SudheerKumar P. , Shiras Anjali , Das Gowry , Jagtap Jayashree C. , Prasad Vandna , Shastry Padma 
Published: September 2007

AbstractTumor associated macrophages (TAMs) constitute a substantial mass in gliomas. The activated macrophages secrete various cytokines that affect diverse functions of tumors. The aim of this study was to elucidate the role of Akt and NF‐κB pathways in resistance to TNF‐α mediated cell death in human gliomas using monolayers and multicellular spheroids (MCS) as in vitro models. Akt and NF‐κB are constitutively expressed and intimately involved in progression of gliomas. The activation of these pathways also renders the tumors resistant to conventional treatments including chemotherapy. While PI3K/Akt is shown to regulate the NF‐κB activation in diverse systems, other studies place NF‐κB upstream of Akt activation. Using a stable IκBα mutant LN‐18 cell line and pharmacological inhibitors to PI3K/Akt (LY294002) and Akt (Akt2), we provide evidence that Akt and NF‐κB are activated independently on stimulation with TNF‐α and both the pathways contribute towards resistance to TNF‐α mediated cell death. TNF‐α‐induced NF‐κB activation independent of PI3K/Akt pathway was also confirmed in human glioma cell lines‐LN‐229 and U373MG. We also show that NF‐κB and Akt are activated during spheroidogenesis and their expression is further enhanced on stimulation with TNF‐α implicating their involvement in resistance to cell death. The findings thus underscore the relevance of spheroids as appropriate in vitro models for studying the signaling pathways in drug induced resistance. © 2007 Wiley‐Liss, Inc.
HDAC3 overexpression and colon cancer cell proliferation and differentiation
Authors: Spurling Colleen C. , Godman Cassandra A. , Noonan Emily J. , Rasmussen Theodore P. , Rosenberg Daniel W. , Giardina Charles 
Published: September 2007

AbstractAn immunohistochemical analysis of human colorectal adenocarcinomas showed that cancer cells express widely varying levels of HDAC3. The SW480 colon cancer cell line was found to express high levels of HDAC3 compared to other colon cancer cell lines. p21 was poorly induced in SW480 cells relative to the lower HDAC3‐expressing HT‐29 cells. RNAi‐induced reduction of HDAC3 in SW480 cells increased their constitutive, butyrate‐, TSA‐, and TNF‐α‐induced expression of p21, but did not cause all the gene expression changes induced upon general histone deacetylase (HDAC) inhibition. SW480 cells with lower HDAC3 expression appeared to be poised for gene expression responses with increased histone H4‐K12 acetylation, but not K5, K8, or K16 acetylation. Even though p21 was readily activated in HT29 cells, HDAC3 siRNA nonetheless stimulated p21 expression in these cells to a greater degree than HDAC1 and HDAC2 siRNA. SW480 cells with lower HDAC3 levels displayed an enhanced cell cycle arrest and growth inhibition by butyrate, but without changes in apoptosis or sensitivity to chemotherapeutic agents. As reported for other colon cancer cell lines, butyrate induced the rapid downregulation of the secretory cell differentiation markers mucin 2 and intestinal trefoil factor in SW480 cells. Interestingly, selective HDAC3 inhibition was sufficient to downregulate these genes. Our data support a central role for HDAC3 in regulating the cell proliferation and differentiation of colon cancer cells and suggest a potential mechanism by which colon cancers may become resistant to luminal butyrate. © 2007 Wiley‐Liss, Inc.
Polymorphism of XRCC1 and the frequency of mutation in codon 249 of the p53 gene in hepatocellular carcinoma among guangxi population, China
Authors: Long Xi Dai , Ma Yun , Huang Hong Dong , Yao Jin Guang , Qu De Ying , Lu Yun Long 
Published: September 2007

AbstractIn hepatocellular carcinoma (HCC), hotspot mutation in codon 249 of the p53 gene has been associated with exposure to aflatoxin B1 (AFB1). While the polymorphism of DNA repair gene X‐ray repair cross‐complementary group 1 (XRCC1) Arg399Gln may be related with AFB1‐DNA adducts and gene mutations. Five hundred one HCCs were included in this study to investigate the role of the XRCC1 codon 399 polymorphism on hotspot mutation in codon 249 of the p53 gene. The genotypes of XRCC1 codon 399 and p53 codon 249 were examined by PCR‐RFLP. The HCC patients with XRCC1 genotypes with 399 Gln (namely: XRCC1‐AG/GG) exhibited a significantly higher frequency of the p53 hotspot mutations in codon 249 than those with the wild‐type homozygote of XRCC1 [namely: XRCC1‐AA, adjusted odds ratio (OR) = 6.77, 95% confidence interval (CI) = 4.34–10.57]. Compared with those individuals who did express XRCC1‐AA as reference (OR = 1), moreover, individuals featuring XRCC1‐AG/GG and AFB1‐DNA adducts did experience a significantly greater frequency of the hotspot mutation in codon 249 of the p53 gene (adjusted OR = 28.37, 95% CI = 13.19–61.02, P < 0.01). This study suggests that the XRCC1 Arg399Gln polymorphism and AFB1‐DNA adducts are associated with the increased frequency of the p53 mutations in codon 249. © 2007 Wiley‐Liss, Inc.
“Recumbent” gait: Relationship to the phenotype of “astasia‐abasia”?
Authors: Boogaarts Hieronymus D. , F. Abdo Wilson , Bloem Bastiaan R. 
Published: September 2007

AbstractPsychogenic gait disorders can present in many different ways. Among patients with a pure psychogenic gait disorder, buckling of the knee is the most common feature, followed by astasia‐abasia. Here, we describe one such patient with a very unusual gait disturbance that might be regarded as a variant of astasia‐abasia. The patient characteristics are described and discussed in a historical context. © 2007 Movement Disorder Society
Height as a potential indicator of early life events predicting Parkinson's disease: A case‐control study
Authors: Ragonese Paolo , D'Amelio Marco , Callari Graziella , Aiello Fabio , Morgante Letterio , Savettieri Giovanni 
Published: September 2007

AbstractAim of this study was to investigate the relationship between height in young adult age and Parkinson's disease (PD) risk. We included 266 persons affected by idiopathic PD. Patients were matched by age and sex to 266 controls by a random selection from the municipality of residence. We collected information about height preceding PD from official documents where these characteristics referred to young adult age (nearly 30 years). We compared height in cases and controls by calculating differences in mean distribution and by χ2 analyses. Crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated by logistic regression models. Mean height was significantly lower in persons affected by PD compared to controls (P = 0.03). Difference was significant only in men (P = 0.001). Logistic regression models showed an inverse association between height and PD (OR 0.35; CI 0.16, 0.79; P < 0.01 comparing individuals in the highest percentiles of height with those in the lowest). Our results indicate an association between height and PD in men. Considering that dopamine sensitivity in the hypothalamic‐pituitary axis is related to adult height, our findings suggest a relationship between PD and factors modulating somatic growth early in life. © 2007 Movement Disorder Society
α‐Amido boronic acids: A synthetic challenge and their properties as serine protease inhibitors
Authors: Matteson Donald S. 
Published: September 2007

AbstractThis review includes a personal account of the history of the development of the α‐amido boronic acid synthesis and related chemistry in the author's laboratory, as well as a review of some of the more significant developments that have occurred elsewhere more recently. The simple initial target, suggested by biochemist G. E. Lienhard, proved much more elusive to reach than anticipated.1 The circuitous effort that ultimately revealed the deceptively simple successful route,1 for which there is still no alternative, will be described. The properties of these compounds as enzyme inhibitors will be described very briefly. More extensive reviews of the enzyme inhibiting properties of α‐amido boronic acids have appeared recently.2 © 2007 Wiley Periodicals, Inc. Med Res Rev, 28, No. 2, 233–246, 2008
The attempted and actual assault scale (attacks)
Authors: Bowers Len , Nijman Henk , Palmstierna Tom 
Published: September 2007

AbstractThe Attempted and Actual Assault Scale (Attacks) was designed to record the nature and severity of inpatient assaults. To explore the psychometric properties of the Scale, a videotape of interpersonal assaults was compiled with clips from regular television broadcasts. During a meeting of the European Violence in Psychiatry Research Group (EVIPRG), 22 members from 14 different countries were instructed to rate the videotaped assaults on both the MOAS and the Attacks. Inter‐rater reliability – in terms of intra‐class correlation coefficients – was 0.70 for Attacks and 0.48 for MOAS severity scores. Attacks severity scores turned out to be significantly associated with the judgments of the raters about the severity of the observed assaults (Spearman's ρ = 0.70). It is concluded that the psychometric properties of the newly developed Attacks are promising. Copyright © 2007 John Wiley & Sons, Ltd.
The generalizability of the Buss–Perry Aggression Questionnaire
Authors: Gerevich József , Bácskai Erika , Czobor Pál 
Published: September 2007

AbstractAggressive and hostile behaviours and anger constitute an important problem across cultures. The Buss–Perry Aggression Questionnaire (AQ), a self‐rating scale was published in 1992, and has quickly become the gold‐standard for the measurement of aggression. The AQ scale has been validated extensively, but the validation focused on various narrowly selected populations, typically, on samples of college students. Individuals, however, who are at risk of displaying aggressive and hostile behaviours may come from a more general population. Therefore, it is important to investigate the scale's properties in such a population. The objective of this study was to examine the factorial structure and the psychometric properties of the AQ scale in a nationally representative sample of the Hungarian adult population.A representative sample of 1200 subjects was selected by a two‐step procedure. The dimensionality and factorial composition of the AQ scale was investigated by exploratory and confirmatory factor analyses. Since spurious associations and increased factorial complexity can occur when the analysis fails to consider the inherently categorical nature of the item level data, this study, in contrast to most previous studies, estimated the correlation matrices subjected to factor analysis using the polychoric correlations. The resulting factors were validated via sociodemographic characteristics and psychopathological scales obtained from the respondents.The results showed that based on the distribution of factor loadings and factor correlations, in the entire nationally representative sample of 1200 adult subjects, from the original factor structure three of the four factors (Physical and Verbal Aggression and Hostility) showed a good replication whereas the fourth factor (Anger) replicated moderately well. Replication further improved when the sample was restricted in age, i.e. the analysis focused on a sample representing the younger age group, comparable to that used in the original Buss–Perry study. Similar to the Buss–Perry study, and other investigations of the AQ scale, younger age and male gender were robustly related to physical aggression. In addition, level of verbal aggression was different between the two genders (with higher severity in males) whereas hostility and anger were essentially the same in both genders.In conclusion, the current study based on a representantive sample of adult population lends support to the use of the AQ scale in the general population. The authors suggest to exclude from the AQ the two inverse items because of the low reliability of these items with regard to their hypothesized constructs. Copyright © 2007 John Wiley & Sons, Ltd.