bluuebunny/crossref_metadata_2025_split huggingface dataset:
Xanthohumol inhibits inflammatory factor production and angiogenesis in breast cancer xenografts
Authors: Monteiro Rosário , Calhau Conceição , Silva Artur Oliveira e , Pinheiro‐Silva Sandra , Guerreiro Susana , Gärtner Fátima , Azevedo Isabel , Soares Raquel 
Published: March 2008

AbstractXanthohumol (XN), a natural polyphenol present in beer, is known to exert anti‐cancer effects. However, its precise mechanisms are not yet clearly defined. The aim of this study was to investigate the effect of oral administration of XN in breast cancer xenografts in nude mice. Proliferation and apoptosis were first examined in MCF7 cell cultures after incubation with XN by trypan blue exclusion assay, [3H]‐thymidine incorporation, KI67 immunostaining and TUNEL. Morphological and histological characteristics of tumours from XN‐treated or control (vehicle‐treated) mice were compared. Immunohistochemistry for proliferative, inflammatory and endothelial cell markers was performed and activation of nuclear factor kappa B (NFκB) pathway was assessed by ELISA. In vitro MCF7 cell proliferation decreased in a dose‐dependent manner. Oral administration of XN to nude mice inoculated with MCF7 cells resulted in central necrosis within tumours, reduced inflammatory cell number, focal proliferation areas, increased percentage of apoptotic cells and decreased microvessel density. Anti‐angiogenic effects of XN were further confirmed by immunoblotting for factor VIII expression in XN‐treated tumours as compared to controls. Decreased immunostaining for NFκB, phosphorylated‐inhibitor of kappa B and interleukin‐1β were also observed as well as a significant decrease in NFκB activity to 60% of control values. These novel findings indicate that XN is able to target both breast cancer and host cells, namely inflammatory and endothelial cells, suggesting its potential use as a double‐edge anti‐cancer agent. J. Cell. Biochem. 104: 1699–1707, 2008. © 2008 Wiley‐Liss, Inc.
The effects of erdosteine, N‐acetylcysteine, and vitamin E on nicotine‐induced apoptosis of hippocampal neural cells
Authors: Demiralay Rezan , Gürsan Nesrin , Erdem Havva 
Published: March 2008

AbstractThis study investigated the frequency of apoptosis in rat hippocampal neural cells after intraperitoneal nicotine injection, examining the roles of the inflammatory markers myeloperoxidase (MPO) and tumor necrosis factor alpha (TNF‐α) in nicotine‐induced brain damage and the protective effects of three known antioxidant agents, N‐acetylcysteine (NAC), erdosteine, and vitamin E. Female Wistar rats were divided into seven groups, each composed of nine rats: 2 negative control groups, 2 positive control groups, one erdosteine‐treated group (500 mg/kg), one NAC‐treated group (500 mg/kg), and one vitamin E‐treated group (500 mg/kg). Nicotine was intraperitoneally injected at a dosage of 0.6 mg/kg for 21 days. Following nicotine injection, the antioxidants were administered orally; treatment was continued until the rats were killed. Apoptosis level in hippocampal neural cells was determined by using TUNEL (terminal deoxynucleotidyl transferase‐mediated dUTP nick endlabeling) method. Staining of cytoplasmic TNF‐α in hippocampal neural cells and hippocampus MPO activity were evaluated by immunohistochemistry. Nicotine administration had no effect on local TNF‐α production, or hippocampal MPO activity. The treatments with erdosteine, NAC and vitamin E significantly reduced the rate of nicotine‐induced hippocampal neural cell apoptosis. This findings suggest that erdosteine and NAC can be as effective as vitamin E in protecting against nicotine‐induced hippocampal neural cell apoptosis. J. Cell. Biochem. 104: 1740–1746, 2008. © 2008 Wiley‐Liss, Inc.
Differential regulation of HSP70 expression by the JNK kinases SEK1 and MKK7 in mouse embryonic stem cells treated with cadmium
Authors: Nishitai Gen , Matsuoka Masato 
Published: March 2008

AbstractJNK, a member of the mitogen‐activated protein kinases (MAPKs), is activated by the MAPK kinases SEK1 and MKK7 in response to environmental stresses. In the present study, the effects of CdCl2 treatment on MAPK phosphorylation and HSP70 expression were examined in mouse embryonic stem (ES) cells lacking the sek1 gene, the mkk7 gene, or both. Following CdCl2 exposure, the phosphorylation of JNK, p38, and ERK was suppressed in sek1−/− mkk7−/− cells. When sek1−/− or mkk7−/− cells were treated with CdCl2, JNK phosphorylation, but not the phosphorylation of either p38 or ERK, was markedly reduced, while a weak reduction in p38 phosphorylation was observed in sek1−/− cells. Thus, both SEK1 and MKK7 are required for JNK phosphorylation, whereas their role in p38 and ERK phosphorylation could overlap with that of another kinase. We also observed that CdCl2‐induced HSP70 expression was abolished in sek1−/− mkk7−/− cells, was reduced in sek1−/− cells, and was enhanced in mkk7−/− cells. Similarly, the phosphorylation of heat shock factor 1 (HSF1) was decreased in sek1−/− mkk7−/− and sek1−/− cells, but was increased in mkk7−/− cells. Transfection with siRNA specific for JNK1, JNK2, p38α, ERK1, or ERK2 suppressed CdCl2‐induced HSP70 expression. In contrast, silencing of p38β or p38γ resulted in further accumulation of HSP70 protein. These results suggest that HSP70 expression is up‐regulated by SEK1 and down‐regulated by MKK7 through distinct MAPK isoforms in mouse ES cells treated with CdCl2. J. Cell. Biochem. 104: 1771–1780, 2008. © 2008 Wiley‐Liss, Inc.
JNK modulates the effect of caspases and NF‐κB in the TNF‐α‐induced down‐regulation of Na+/K+ATPase in HepG2 cells
Authors: Kassardjian Ari , Kreydiyyeh Sawsan Ibrahim 
Published: March 2008

AbstractAn inhibition of the Na+/K+ATPase was previously shown to accompany and potentiate apoptosis in different experimental models. Since TNF‐α is known to be a pro and anti‐apoptotic cytokine, this work was undertaken to study the effect of TNF‐α on the Na+/K+ATPase in HepG2 cells and to determine the signaling pathway involved. Cells were incubated for 1 h with TNF‐α in presence and absence of PDTC, SP600125 and FK009, respective inhibitors of NF‐KB, c‐JNK, and caspases. The activity of the pump was assayed by measuring the ouabain‐inhibitable release of inorganic phosphate, and changes in its expression were monitored by western blot analysis. TNF‐α decreased significantly the activity and protein expression of the Na+/K+ATPase. NF‐κB and caspases were found to be the main effectors of the cytokine, mediating respectively down‐regulation and up‐regulation of the pump. Their activity was however modulated at 1 h by c‐JNK, which stimulated the caspases and inhibited NF‐κB, resulting in a net inhibition of the ATPase, and probably favoring the apoptotic pathway. J. Cell. Physiol. 216: 615–620, 2008, © 2008 Wiley‐Liss, Inc.
High‐pressure Raman spectroscopy study of α and γ polymorphs of AlH3
Authors: Tkacz Marek , Palasyuk Taras , Graetz Jason , Saxena Surendra 
Published: March 2008

AbstractFor the first time, Raman spectroscopy of α and γ polymorphs of AlH3 has been performed in the pressure range from ambient up to 16.9 and 32.7 GPa, respectively using the diamond anvil cell (DAC) technique. An analysis of pressure response wavenumbers (ν) for α‐AlH3 showed a change of dνi/dP at a pressure of about 8 GPa and may indicate a monoclinic distortion from the initially hexagonal α‐AlH3. The distortion is stable at least up to 16.9 GPa. The γ form exhibited more complex behavior transforming to the α form at a pressure of about 12 GPa. The structural phase transition was shown to be an irreversible and kinetically slow process that required at least 5 h to complete. Copyright © 2008 John Wiley & Sons, Ltd.
Preparation and properties of dipropargyl ether of bisphenol A‐modified bismaleimide resins and composites
Authors: Rong Zhuxia , Huang Fuwei , Shen Xuening , Huang Farong 
Published: March 2008

AbstractA kind of modified bismaleimide resin, with good heat resistance and processing properties for advanced composites, was developed. The modifier, dipropargyl ether of bisphenol A (DPBPA), was prepared by a phase‐transfer catalyzing procedure, characterized by FTIR, 1H NMR, and elementary analysis, and used to modify 4,4′‐bismaleimidodiphenylmethane (BMDPM). The thermopolymerization of a DPBPA‐modified BMDPM resin was followed up by FTIR. The curing of the resin was investigated by differential scanning calorimeter and gelation characterization. The relation of viscosity and temperature was used to characterize the processability of the resin. The results of DMA analysis showed that the cured DPBPA‐modified BMDPM resins had a glass transition temperature higher than 320°C. The carbon fiber (T700) reinforced composites showed excellent flexural properties at ambient temperature and at 250°C. DPBPA could effectively improve mechanical properties without deteriorating heat resistance of the BMDPM resin a lot. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effect of γ‐irradiation on the physical properties and dyeability of poly(vinyl butyral) blends with polystyrene and poly(ethylene glycol)
Authors: Nizam El‐Din Horia M. , El‐Naggar Abdel Wahab M. 
Published: March 2008

AbstractCast films of polymer blends essentially based on poly(vinyl butyral) (PVB) and equal ratios of polystyrene (PS) and poly(ethylene glycol) (PEG) were prepared from benzene and butyl alcohol solutions of the individual polymers. The effect of γ‐irradiation on the thermal decomposition and tensile mechanical properties was investigated. Moreover, the effect of γ‐irradiation on the dye affinity of PVB/PS and PVB/PEG for basic and acid dyestuffs was studied. The thermogravimetric analysis (TGA) study showed that the unirradiated PVB polymer films prepared in benzene displayed higher thermal stability than the same polymer films prepared in butanol. However, in all cases the thermal stability was found to increase with increasing γ‐irradiation dose. On the other hand, PVB/PS blend possesses higher thermal stability than PVB/PEG, as shown from the determination of the weight loss (%) at different heating temperatures, the temperatures of the maximum rate of reaction and the activation energy. While, pure PS films showed the stress‐strain behavior of brittle polymers, PVB/PS films showed the behavior of tough polymers with yielding properties. The results of dyeing clearly showed that the solvent type, blend composition, and irradiation dose are determining factors for the dye affinity for basic or acid dyes. For example, unirradiated PVB films prepared from butanol displayed a higher affinity for the basic and acid dyes than the same polymer prepared from the same benzene. However, PVB prepared from butanol showed higher affinity to the dyes than PS prepared from the same solvent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Modification of asphalt by packaging waste‐polyethylene
Authors: Fang Changqing , Li Tiehu , Zhang Zengping , Jing Deqi 
Published: March 2008

AbstractThe “white pollution” made of packaging waste polymers and its recycling has become a common issue. In this article, the retrieved waste milk‐packing bag (its main ingredients was polyethylene) was selected to modify the ordinary oil asphalt. Asphalt was modified with 1, 3, 6, and 9 wt% content of waste‐polyethylene. The results showed that the softening point and the freeze‐to‐crack stress of asphalt increased the penetration and the freeze‐to‐crack temperature decreased after modification. The comprehensive performance of raw asphalt improved noticeably. Infrared analysis suggests that waste‐polyethylene in packaging (WPE) combines the matrix of asphalt through physical mixture modification. And the modification mechanism of WPE was studied by the analysis of its micro structure, the characteristics of WPE, the effects of Crack pinning and Silver Shear yield in the decentralized process. Using waste packaging polymers to modify the asphalt proved to be an ideal way, for not only solving the problem of “white pollution”, but also for improving the performance of asphalt. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Investigation of flow properties of asphalt binders containing polymer modifiers
Authors: Nien Yu‐Hsun , Yeh Pei‐Hung , Chen Wei‐Chyum , Liu Wen‐Tsung , Chen Jean‐Hong 
Published: March 2008

AbstractModified asphalts using polymeric additives, including isotactic polypropylene (iPP) and different degrees of chlorinated polypropylene (CPP), have been prepared and examined using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), rotational viscometer, and dynamic shear rheometer (DSR) in this study. The results of DSC studies show that different levels of the crystallization occur in asphalt/iPP blends because most of the crystallinity of iPP remain intact in the blend, while those asphalt samples having CPP tend to affect the thermal behavior in the DSC thermograms because of increasing the amorphous region of CPP. From the images of SEM, the distinctions of the phase distributions between the asphalt/iPP and asphalt/CPP blends illustrate that the chlorine content in CPP is a significant factor in controlling its compatibility with asphalt. The rheological studies show that the asphalt blends containing CPP (26 wt% of Cl) exhibit higher viscosity in terms of higher temperature to get Newtonian behavior and display superior rutting resistance to avoid permanent deformation at high temperature. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Synthesis and characterization of graft copolymers of ethyl acrylate/acrylamide mixtures onto starch
Authors: Zhang Bin , Zhou Yongyuan 
Published: March 2008

AbstractGraft copolymerization of ethyl acrylate/acrylamide onto corn starch using potassium permanganate–citric acid initiation system was investigated. Major factors affecting the polymerization reaction were thoroughly investigated in terms of initiator concentration, monomer concentration, polymerization time, polymerization temperature, and starch/liquor, and the obtained results implied that the polymer yield which were expressed by total monomer conversion, grafting ratio, and grafting efficiency were determined by these factors. The optimum reaction conditions were as follows: starch, 30 g; potassium permanganate (based on weight of starch), 0.1%; citric acid (based on weight of starch), 0.5%; ethyl acrylate, 20%; acrylamide, 0.4 g; time, 3 h; temperature, 40°C; starch/liquor, 1:3. We concluded that the initiator of potassium permanganate–citric acid system could be used as a cheap initiator in manufacturing the starch graft copolymer. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Effects of crosslinking density on structure and properties of interpenetrating polymer networks from polyurethane and nitroguar gum
Authors: Fan Qingchun , Xiao Chaobo 
Published: March 2008

AbstractSemi‐interpenetrating polymer networks (semi‐IPNs) of castor oil‐based polyurethane prepolymer and nitroguar gum (NGG) with different crosslinking density of the PU network, coded as UNG films, were prepared through varying the trimethanol propane (TMP)/1,4‐butanediol (BDO) molar ratios in the chain extender mixture. The effects of crosslinking density on the structure and properties of the UNG films was investigated by attenuated total reflection Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, scanning electron microscopy, crosslinking density measurements, solvent‐extracting tests, and tensile tests. The experimental results revealed that incorporation of TMP crosslinker into the hard segments of polyurethane resulted in a decrease in the aggregation of hard segments. With an increase of the TMP/BDO molar ratios, the semi‐IPN films exhibited the higher crosslinking density, glass temperature (Tg), stiffness, and tensile strength (σb). Furthermore, the experimental results also indicated that NGG restricted the formation of crosslinking networks when the TMP content is relatively high, which led to the negative deviation of the theoretically predicted crosslinking density and Dibenedetto's equation. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Reverse ATRP process of acrylonitrile in the presence of ionic liquids
Authors: Hou Chen , Qu Rongjun , Ji Chunnuan , Sun Changmei , Wang Chunhua 
Published: March 2008

AbstractAn ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C4mim] [BF4]), was first used as the solvent in azobisisobutyronitrile (AIBN)‐initiated reverse atom transfer radical polymerization (RATRP) of acrylonitrile with FeCl3/succinic acid (SA) as the catalyst system. The polymerization in [C4mim][BF4] proceeded in a well‐controlled manner as evidenced by kinetic studies. Compared with the polymerization in bulk, the polymerization in [C4mim][BF4] not only showed the best control of molecular weight and its distribution but also provided rather rapid reaction rate with the ratio of [C4mim][BF4] at 200:1:2:4. The polymerization apparent activation energies in [C4mim][BF4] and bulk were calculated to be 48.2 and 55.7 kJ mol−1, respectively. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization in [C4mim][BF4] via a conventional ATRP process. [C4mim][BF4] and the catalyst system could be easily recycled and reused after simple purification and had no effect on the living nature of polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2701–2707, 2008
Novel hepatoma‐targeting micelles based on chemoenzymatic synthesis and self‐assembly of galactose‐functionalized ribavirin‐containing amphiphilic random copolymer
Authors: Li Xia , Wu Qi , Lu Min , Zhang Fu , Lin Xianfu 
Published: March 2008

AbstractHepatoma‐targeting micelles were successfully prepared by self‐assembly of galactose‐functionalized ribavirin‐containing amphiphilic random copolymer as novel drug delivery vehicles. The ribavirin‐containing random copolymer with galactose as the targeting ligand was facilely synthesized by combining enzymatic transesterification with radical polymerization and fully characterized by FTIR, NMR, and GPC. The formation of micelle‐type aggregates from the random copolymer was verified by UV–vis and fluorescence spectroscopy using pyrene as the guest molecule. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) experiments revealed that the micelles were well dispersed as spherical nanoparticles in water, whose hydrodynamic diameter was 217 ± 19 nm. Their biological recognition to fluorescein‐labeled peanut agglutinin investigated by confocal laser scanning microscopy (CLSM) proved the existence of hydrophilic galactose targeting moieties on the surface of micelles. Cell cytotoxicity tests and the inhibition experiment of galactose performed by MTT assay showed that the micelles had evident targeting function to hepG2 cells and the galactose moieties on the surface of micelles mediated cellar uptake of micelles. In vitro release studies indicated that ribavirin could be slowly released from the copolymer with pseudo zero‐order kinetics. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2734–2744, 2008
Thermodynamic of polymer mixtures: The LCT applied to the poly(styrene)/poly(vinyl methylether) system
Authors: Vicini Silvia , Princi Elisabetta , Pedemonte Enrico 
Published: March 2008

AbstractIn this article, the Lattice Cluster Theory developed by Freed and coworkers is applied to the poly(styrene)/poly(vinyl methylether) system by measuring the enthalpy and the volume variation associated with the mixing of the two homopolymers. It comes out that the chains architectures previously chosen for the two macromolecules based on the phase diagram and of the partition function developed by the theory correctly predicts the sign of both ΔHM and ΔVM. The foreseen trends as function of mixture composition fit the experimental data only for ΔVM; ΔHM is higher than predicted, asymmetrical and independent on the chain lengths of the components. The conclusion is that the theory needs some final touches in order to obtain a better agreement with experiments. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 791–797, 2008
Blast charts for explosive evaporation of superheated liquids
Authors: van den Berg A.C. 
Published: March 2008

AbstractExplosive evaporation of superheated liquids is a hazard faced in many sectors of the process industries. The assumption that the explosive evaporation process is as fast as the inertia of the expanding mix of vapor and liquid in the surrounding air allows has been used as a safe and conservative starting point for the numerical computation of the blast. The result represents the maximum blast potential of an evaporating superheated liquid.The modeling has been applied for the compilation of blast charts for some gaseous substances that are usually stored, transported, or handled in liquefied form. Because the blast charts have been directly computed from the gas dynamics of an explosive evaporation process, they enable a more realistic assessment of the blast potential of superheated liquids than the usual methods based on TNT‐equivalency. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Spectroscopic ellipsometry study of amorphous SrxBa1–xNb2O6 thin films obtained by pulsed laser deposition
Authors: Ion V. , Gâlcă A. C. , Scărisoreanu N. D. , Filipescu M. , Dinescu M. 
Published: March 2008

AbstractOptical properties of amorphous Strontium Barium Niobate (a‐SBN) thin films are investigated using spectroscopic ellipsometry. Since the SBN can be applied to optoelectronic devices, the dispersion of refractive index is desirable. The films are obtained by Pulsed Laser Deposition (PLD) onto MgO and Si substrates by targeting a SBN:60 monocrystal. The dielectric function of a‐SBN is approximated using a single Tauc‐Lorentz oscillator model. Thicknesses of the films and of their rough layer are in agreement with SEM and AFM results. The dispersion of the refractive index is presented in the 1 –5 eV range. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Condensation and cleaning of an organometallic copper compound to/from porous low‐dielectric constant thin films in supercritical carbon dioxide
Authors: Kondoh E. , Ukai E. , Aruga S. 
Published: March 2008

AbstractPorous low‐dielectric‐constant (low‐k) thin films are demanded as insulating material for high‐performance integrated circuits. One of the key technologies matching low‐k processing is the use of supercritical carbon dioxide (scCO2) fluids. ScCO2 has a nano‐penetration capability as well as solvent capability, which makes it a promising medium for the cleaning and modification of low‐k pores. However, few studies have been reported so‐far on in‐situ ellipsometric measurement within supercritical fluids. We have developed an in‐situ ellipsometry technique for use in scCO2. In this ar‐ticle, the sorption behaviour of an organometallic compound, Cu(dibm)2, on organosilica‐based low‐k thin films is reported as a model case of Cu contamination and the cleaning of low‐k pores. Reversible adsorption/desorption behaviour was observed when the amount of Cu(dibm)2 loaded was low, while less reversibility was observed when a larger amount of Cu(dibm)2 was used. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Suppression of backside reflections from transparent substrates
Authors: Synowicki R. A. 
Published: March 2008

AbstractA variety of simple non‐destructive techniques were investigated to suppress backside reflections from transparent glass and plastic substrates. Different “glassy” materials such as translucent adhesive tape, white glue, grease, paint, and modelling clay were investigated and found to work well for substrate materials with refractive indices in the range of 1.35 to 1.60, including materials such as fused silica, float glass, display glass, microscope slides, plastic sheets, etc. These back‐surface suppression techniques are also useful in suppressing anisotropic effects from plastic substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)