bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acteoside inhibits PMA‐induced matrix metalloproteinase‐9 expression via CaMK/ERK‐ and JNK/NF‐κB‐dependent signaling
Authors: Hwang Yong Pil , Kim Hyung Gyun , Choi Jae Ho , Park Bong Hwan , Jeong Myung Ho , Jeong Tae Cheon , Jeong Hye Gwang 
Published: November 2010

AbstractScope: Acteoside, an active phenylethanoid glycoside found in bitter tea and many medicinal plants, displays chemopreventive properties. The aim of our study was to determine the effect of acteoside on tumor invasion and migration; the possible mechanisms involved in this inhibition were investigated in human fibrosarcoma HT‐1080 cells.Methods and results: We employed invasion, migration and gelatin zymography assays to characterize the effect of acteoside on HT‐1080 cells. Transient transfection assays were performed to investigate gene promoter activities, and immunoblot analysis to study its molecular mechanisms of action. We found that acteoside suppresses phorbol‐12‐myristate‐13‐acetate (PMA)‐enhanced matrix metalloproteinase‐9 (MMP‐9) expression at the protein, mRNA, and transcriptional levels through the suppression of NF‐κB activation. In addition, acteoside repressed the PMA‐induced phosphorylation of ERK1/2 (ERK, extracellular regulated kinase) and JNK1/2. Further, we found that acteoside decreased the PMA‐induced influx of Ca2+ and repressed PMA‐induced calmodulin‐dependent protein kinase (CaMK) phosphorylation. Furthermore, treatment with BAPTA/AM, W7, or capsazepine markedly decreased PMA‐induced MMP‐9 secretion and cell migration, as well as ERK and JNK/NF‐κB activation.Conclusion: Acteoside inhibited PMA‐induced invasion and migration of human fibrosarcoma cells via Ca2+‐dependent CaMK/ERK and JNK/NF‐κB‐signaling pathways. Acteoside therefore has the potential to be a potent anticancer agent in therapeutic strategies for fibrosarcoma metastasis.
Potential health‐promoting effects of astaxanthin: A high‐value carotenoid mostly from microalgae
Authors: Yuan Jian‐Ping , Peng Juan , Yin Kai , Wang Jiang‐Hai 
Published: November 2010

AbstractThe ketocarotenoid astaxanthin can be found in the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp., and the red yeast Phaffia rhodozyma. The microalga H. pluvialis has the highest capacity to accumulate astaxanthin up to 4–5% of cell dry weight. Astaxanthin has been attributed with extraordinary potential for protecting the organism against a wide range of diseases, and has considerable potential and promising applications in human health. Numerous studies have shown that astaxanthin has potential health‐promoting effects in the prevention and treatment of various diseases, such as cancers, chronic inflammatory diseases, metabolic syndrome, diabetes, diabetic nephropathy, cardiovascular diseases, gastrointestinal diseases, liver diseases, neurodegenerative diseases, eye diseases, skin diseases, exercise‐induced fatigue, male infertility, and HgCl2‐induced acute renal failure. In this article, the currently available scientific literature regarding the most significant activities of astaxanthin is reviewed.
Regulation of genes involved in lipid metabolism by dietary oxidized fat
Authors: Ringseis Robert , Eder Klaus 
Published: November 2010

AbstractAlthough oxidized fats are widely considered to have detrimental effects on human health, a large number of feeding studies with experimental animals have consistently demonstrated that oxidized fats, compared with fresh fats, cause a reduction in the concentrations of triacylglycerols and cholesterol in liver and plasma. The reason for these effects became clear when recently it was shown that thermo‐oxidized fats contain characteristic substances such as hydroxylated fatty acids and cyclic fatty acid monomers which are potent ligands and activators of peroxisome proliferator‐activated receptor α – a transcription factor controlling genes involved in fatty acid and lipoprotein metabolism. In addition, oxidized fats have also been reported to inhibit expression of genes involved in fatty acid synthesis and cholesterol homeostasis. These effects are mediated by inhibiting the maturation of sterol regulatory‐element binding proteins, which are transcription factors regulating genes involved in fatty acid synthesis and cholesterol homeostasis. This review summarizes the phenotypical alterations of lipid metabolism observed in feeding studies dealing with oxidized fats and addresses the molecular mechanisms underlying these lipid metabolism alterations, in particular the lipid lowering effects of dietary oxidized fats.
The influence of soft segment length on structure and properties of poly(trimethylene terephthalate)‐block‐poly(tetramethylene oxide) segmented random copolymers
Authors: Szymczyk A. , Nastalczyk J. , Sablong R.J. , Roslaniec Z. 
Published: November 2010

AbstractTwo series of multiblock poly(ether‐ester)s based on poly(trimethylene terephthalate) (PTT) as the rigid segments and poly(tetramethylene oxide) (PTMO) as the flexible/soft segments were synthesized with the aim of developing of the new family polyester thermoplastic elastomers (TPEs) based on PTT as rigid segment. The content of PTMO segments in the polymer chains was varied from 20 to 80 wt%. The investigations were mainly focused on the influence of flexible segments length with starting PTMG molecular weight at 1000 and 2000 g/mol, respectively, on the phase structure, thermal and mechanical properties of resulting copolymers. The copolymers were characterized by Size Exclusion Chromatography (SEC), Differential Scanning Calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), Wide‐angle X‐ray scattering (WAXS), Small‐angle X‐ray scattering (SAXS), and other standard physical methods. Cyclic tensile properties of them were studied with the aim to evaluate the elastic properties. SEC results clearly demonstrated the formation of molecular weight segmented copolymers with microphase separated structure as denoted by DSC and DMTA. The enhanced phase separation was observed for copolymers containing longer flexible segments.According to the characterizations, copolymers containing 50–80 wt% of flexible segments showed elastic behavior. Comparison of the values of permanent set for copolymers with shorter and longer flexible segments has shown that copolymers containing 30 and 40 wt% of long PTMO flexible segments have the best elastic properties (low permanent set). Copyright © 2010 John Wiley & Sons, Ltd.
Band gap‐voltage offset and energy production in next‐generation multijunction solar cells
Authors: King R. R. , Bhusari D. , Boca A. , Larrabee D. , Liu X.‐Q. , Hong W. , Fetzer C. M. , Law D. C. , Karam N. H. 
Published: November 2010

AbstractThe potential for new 4‐, 5‐, and 6‐junction solar cell architectures to reach 50% efficiency is highly leveraging for the economics of concentrator photovoltaic (CPV) systems.The theoretical performance of such next‐generation cells, and experimental results for 3‐ and 4‐junction CPV cells, are examined here to evaluate their impact for real‐world solar electricity generation. Semiconductor device physics equations are formulated in terms of the band gap‐voltage offsetWoc  (Eg/q) − Voc, to give a clearer physical understanding and more general analysis of the multiple subcell band gaps in multijunction cells. Band gap‐voltage offset is shown experimentally to be largely independent of band gap Egfor a wide range of metamorphic and lattice‐matched semiconductors from 0.67 to 2.1 eV. Its theoretical Egdependence is calculated from that of the radiative recombination coefficient, and at a more fundamental level using the Shockley‐Queisser detailed balance model, bearing out experimental observations. Energy production of 4‐, 5‐, and 6‐junction CPV cells, calculated for changing air mass and spectrum over the course of the day, is found to be significantly greater than for conventional 3‐junction cells. The spectral sensitivity of these next‐generation cell designs is fairly low, and is outweighed by their higher efficiency. Lattice‐matched GaInP/GaInAs/Ge cells have reached an independently confirmed efficiency of 41.6%, the highest efficiency yet demonstrated for any type of solar cell. Light I‐V measurements of this record 41.6% cell, of next‐generation upright metamorphic 3‐junction cells with 40% target production efficiency, and of experimental 4‐junction CPV cells are presented. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of initial power stabilization over crystalline‐Si photovoltaic modules maximum power
Authors: Munoz M.A. , Chenlo F. , Alonso‐García M.C. 
Published: November 2010

AbstractMeasurements that suppliers offer in specification sheets are not always close to the actual power measured in independent laboratories such as CIEMAT. Independent measurements tend to be lower than those printed on the label sometimes even lower than the allowed tolerance indicated by the manufacturer on the same label. Furthermore, a potentially significant power reduction has been reported when Standard EN50380 (which requires photovoltaic (PV) modules to be exposed to more than 20 kWh/m2of sunlight prior to taking the measurements that appear on the label) is followed. This is the initial power stabilization and this work studies the power stabilization that tends to appear in crystalline PV modules. Crystalline PV modules usually decrease in power around 1%, but decreases >4% have also been reported. These power losses are only detected after the mentioned power stabilization. Copyright © 2010 John Wiley & Sons, Ltd.
Impurity‐to‐efficiency simulator: predictive simulation of silicon solar cell performance based on iron content and distribution
Authors: Hofstetter J. , Fenning D. P. , Bertoni M. I. , Lelièvre J. F. , Cañizo1 C. del , Buonassisi T. 
Published: November 2010

AbstractWe present a simulation tool that predicts solar cell efficiency based on iron content in as‐grown wafer and solar cell processing conditions. This “impurity‐to‐efficiency” (I2E) simulation tool consists of three serial components, which are independently and jointly validated using published experimental results: (1) a kinetic model that calculates changes in the distribution of iron and phosphorus atoms during annealing; (2) an electronic model that predicts depth‐dependent minority carrier lifetime based on iron distribution; and (3) a device simulator that predicts solar cell performance based on the minority carrier lifetime distribution throughout the wafer and the device architecture. The I2E model is demonstrated to be an effective predictor of cell performance for both single‐crystalline and multi‐crystalline silicon solar cells. We demonstrate the process optimization potential for the I2E simulator by analyzing efficiency improvements obtained using low‐temperature annealing, a processing concept that has been successfully applied to achieve higher solar cell efficiencies on Fe‐contaminated materials. Copyright © 2010 John Wiley & Sons, Ltd.
Highly thermostable and low birefringent norbornene‐styrene copolymers with advanced optical properties: A potential plastic substrate for flexible displays
Authors: Ban Hoang The , Hagihara Hideaki , Tsunogae Yasuo , Cai Zhengguo , Shiono Takeshi 
Published: November 2010

AbstractThis article reports the synthesis and characterization of an extremely high thermostable cyclic olefin copolymer with advanced optical properties resulting from the vinyl addition copolymerization of norbornene with styrene catalyzed by a substituted fluorenylamidodimethyltitanium catalyst [Me2Si(3,6‐tBu2Flu)(tBuN)]TiMe2 activated with a [Ph3C] [B(C6F5)4]/Al(iBu)3 cocatalyst using o‐dichlorobenzene as solvent. The prepared copolymer possesses a glass transition temperature as high as polyimide (Tg > 300 °C) and a high transmittance which is comparable with that of the conventional optical resins ([T] > 90%). The incorporation of polystyrene, which exhibits a negative birefringence into the vinyl‐added polynorbornene that possesses an intrinsic positive birefringence, effectively reduced the birefringent magnitude of the norbornene‐styrene copolymer due to a mutual compensation between these opposite‐sign birefringences. The absence of any functional and aromatic heterocyclic groups and the presence of highly hydrophobic saturated bicyclic rings in the copolymer main chains effectively prevented the diffusion of water/oxygen and thus enhanced the dimensional and optical stabilities of the material. Preliminary results on the characterization of the thermal stability, mechanical, and optical properties of the vinyl‐added norbornene‐styrene copolymers indicate that they satisfy all the rigorous requirements for a polymer to be applied as a flexible substrate for the manufacturing of the flexible displays. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis and characterization of functional fluorinated telomers
Authors: Durand Nelly , Ameduri Bruno , Boutevin Bernard 
Published: November 2010

AbstractThe synthesis and characterizations of fluorinated telomers based on vinylidene fluoride (VDF) by iodine transfer polymerization (ITP) are presented. These telomers were prepared in the presence of ω‐iodoperfluorinated functional chain transfer agents, C6F13I or C4F9I. ITPs were initiated by thermal decomposition of bis(4‐tert‐butylcyclohexyl) peroxydicarbonate (BBCHPDC), in solution (in the presence of acetonitrile). The obtained telomers were characterized by different analyses such as elemental analyses, nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy, size exclusion chromatography, X‐ray diffraction (XRD), and finally by thermal analyses such as differential scanning calorimetry (DSC) and thermogravimetric analyses. These technical analyses enabled one to assess their chemical structures, various thermal properties, and their crystalline forms. The assignments of the characteristic signals obtained by 19F NMR spectroscopy enabled one to calculate the average degrees of polymerization (DPn) and percentages of CH2CF2I end group functionalities that depend on the initiator and the fractionation process after reaction. A good control of polymerization was shown by the absence of reversed CH2CF2CF2CH2 (VDF–VDF dyads) and narrow polydispersity indices (<1.2). The XRD and DSC evidenced the influence of the chain length of the telomers on the crystallinity rate (>70%) and indicated two crystalline forms, α and β, that depended on DPn values. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Modification of polysulfones by click chemistry: Amphiphilic graft copolymers and their protein adsorption and cell adhesion properties
Authors: Yilmaz Gorkem , Toiserkani Hojjat , Demirkol Dilek Odaci , Sakarya Serhan , Timur Suna , Yagci Yusuf , Torun Lokman 
Published: November 2010

AbstractWell‐defined amphiphilic graft copolymer with hydrophobic polysulfone (PSU) backbone and hydrophilic poly(acrylic acid) (PAA) side chains were synthesized and characterized. For this purpose, commercially available PSU was converted to azido‐functionalized polymer (PSU‐N3) by successive chloromethylation and azidation processes. Independently, poly(tert‐butyl acrylate) (PtBA) with an alkyne‐end‐group is obtained by using suitable initiator in atom transfer radical polymerization (ATRP). Then, this polymer was successfully grafted onto PSU‐N3 by click chemistry to yield polysulfone‐graft‐poly(tert‐butyl acrylate), (PSU‐g‐PtBA). Finally, amphiphilic polysulfone‐graft‐poly(acrylic acid), (PSU‐g‐PAA), membranes were obtained by hydrolyzing precursor the PSU‐g‐PtBA membranes in trifluoroacetic acid. The final polymer and intermediates at various stages were characterized by 1H NMR, FTIR, GPC, and SEM analyses. Protein adsorption and eukaryotic and prokaryotic cell adhesion on PSU‐g‐PAA were studied and compared to those of PSU‐g‐PtBA and unmodified PSU. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Thermally crosslinkable hole‐transporting poly(fluorene‐co‐triphenylamine) for multilayer polymer light‐emitting diodes
Authors: Su Wen‐Fen , Chen Ruei‐Tang , Chen Yun 
Published: November 2010

AbstractThis article reports the synthesis and characterization of a novel thermally crosslinkable hole‐transporting poly (fluorene‐co‐triphenylamine) (PFO‐TPA) by Suzuki coupling reaction, followed with its application in the fabrication of multilayer light‐emitting diodes by wet processes. The thermal, photophysical, and electrochemical properties of PFO‐TPA were investigated by differential scanning calorimeter, thermogravimetric analysis, optical spectroscopy, and cyclic voltammetry, respectively. Thermally crosslinked PFO‐TPA, through pendant styryl groups, demonstrates excellent thermal stability (Td > 400 °C, Tg = 152 °C), solvent resistance, and film homogeneity. Its highest occupied molecular orbital level (−5.30 eV) lies between those of PEDOT:PSS (−5.0 ∼ −5.2 eV) and poly(9,9‐dioctylfluorene) (PFO: −5.70 eV), forming a stepwise energy ladder to facilitate hole injection. Multilayer device with crosslinked PFO‐TPA as hole‐injection layer (HIL) (ITO/PEDOT:PSS/HIL/PFO/LiF/Ca/Al) was readily fabricated by successive spin‐coating processes, its maximum luminance efficiency (3.16 cd/A) were about six times higher than those without PFO‐TPA layer (0.50 cd/A). The result of hole‐only device also confirmed hole‐injection and hole‐transport abilities of crosslinked PFO‐TPA layer. Consequently, the device performance enhancement is attributed to more balanced charges injection in the presence of crosslinked PFO‐TPA layer. The thermally crosslinkable PFO‐TPA is a promising material for the fabrication of efficient multilayer polymer light‐emitting diodes because it is not only a hole‐transporting polymer but also thermally crosslinkable. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Cobalt‐mediated radical polymerization routes to poly(vinyl ester) block copolymers
Authors: Bunck David N. , Sorenson Gregory P. , Mahanthappa Mahesh K. 
Published: November 2010

AbstractCobalt‐mediated radical polymerizations (CMRPs) utilizing redox initiation are demonstrated to produce poly(vinyl ester) homopolymers derived from vinyl pivalate (VPv) and vinyl benzoate (VBz), and their block copolymers with vinyl acetate (VAc). Combining anhydrous Co(acac)2, lauroyl peroxide, citric acid trisodium salt, and VPv at 30 °C results in controlled polymerizations that yield homopolymers with Mn = 2.5–27 kg/mol with Mw/Mn = 1.20–1.30. Homopolymerizations of scrupulously purified VBz proceed with lower levels of control as evidenced by broader polydispersities over a range of molecular weights (Mn = 4–16 kg/mol; Mw/Mn = 1.34–1.65), which may be interpreted in terms of the decreased nucleophilicity of these less electron donating propagating polymer chain ends. Based on these results, we demonstrate that sequential CMRP reactions present a viable route to microphase separated poly(vinyl ester) block copolymers as shown by small‐angle X‐ray scattering analyses. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Ring‐opening polymerization of cyclic esters promoted by phosphido‐diphosphine pincer group 3 complexes
Authors: D'auria Ilaria , Mazzeo Mina , Pappalardo Daniela , Lamberti Marina , Pellecchia Claudio 
Published: November 2010

AbstractPhosphido‐diphosphine Group 3 metal complexes 1–4 [(o‐C6H4PR2)2P‐M(CH2SiMe3)2; R = Ph, 1: M = Y, 2: M = Sc; R = iPr, 3: M = Y, 4: M = Sc] are very efficient catalysts for the ring‐opening polymerization (ROP) of cyclic esters such as ε‐caprolactone (ε‐CL), L‐lactide, and δ‐valerolactone under mild polymerization conditions. In the ROP of ε‐CL, complexes 1–4 promote quantitative conversion of high amount of monomer (up to 3000 equiv) with very high turnover frequencies (TOF) (∼4 × 104 molCL/molI h) showing a catalytic activity among the highest reported in the literature. The immortal and living ROP of ε‐CL and L‐lactide is feasible by combining complexes 1–4 with 5 equiv of 2‐propanol. Polymers with controlled molecular parameters (Mn, end groups) and low polydispersities (Mw/Mn = 1.05–1.09) are formed as a result of fast alkoxide/alcohol exchange. In the ROP of δ‐valerolactone, complexes 1–4 showed the same activity observed for lactide (L‐ and D,L‐lactide) producing high molecular weight polymers with narrow distribution of molar masses. Complexes 1–4 also promote the ROP of rac‐β butyrolactone affording atactic low molecular weight poly(hydroxybutyrate) bearing unsaturated end groups probably generated by elimination reactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Efficient accelerating effect of carbonyldiimidazole on epoxy‐dicyandiamide curing system
Authors: Liu Xiang Dong , Sudo Atsushi , Endo Takeshi 
Published: November 2010

AbstractCarbonyldiimidazole (CDI) was inventively used as an accelerator for the curing reaction of diglycidyl ether of bisphenol A (DGEBA) with dicyandiamide (DICY) and a high acceleration more effective than imidazole in double usage was observed. This result implies the accelerating role of CDI in the curing process is complex and involved not only the release of imidazole. To detail the accelerating mechanism of CDI, a series of curing reactions was studied by differential scanning calorimetry (DSC), NMR, IR, and viscosity monitoring. The results suggested that the accelerating mechanism of CDI involves (1) acylation of DICY with CDI to give the corresponding adduct with enhanced solubility, (2) the consequent release of imidazole that can react with epoxide, and (3) abstraction of proton of DICY by the alkoxide moiety to give the corresponding DICY anion endowed with enhanced nucleophilicity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis and characterization of four alkyl 2‐cyanoacrylate monomers and their precursors for use in latent fingerprint detection
Authors: Tahtouh Mark , Kalman John R. , Reedy Brian J. 
Published: November 2010

AbstractFour novel cyanoacrylates, 2‐cyanoethyl 2‐cyanoacrylate, 1‐cyanoethyl 2‐cyanoacrylate, trideuteromethyl 2‐cyanoacrylate and pentadeuteroethyl 2‐cyanoacrylate have been synthesized using a Diels‐Alder protection/deprotection route involving anthracene. The common route for the synthesis of alkyl 2‐cyanoacrylates was found to be unsatisfactory for the production of small quantities of the targeted cyanoacrylates, which have potential as reagents for the mid‐infrared spectral imaging of fingerprints on difficult surfaces. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Infiltrating P3HT polymer into ordered TiO2 nanotube arrays
Authors: Lim Siew Leng , Liu Yiliang , Liu Gang , Xu Sheng Yong , Pan Hua Yong , Kang En‐Tang , Ong Chong Kim 
Published: November 2010

AbstractInfiltration of regioregular poly(3‐hexyl thiophene) (RR P3HT) polymer into ordered TiO2 nanotube arrays is confirmed by UV–Vis absorption spectrometer measurement, time‐of‐flight secondary ion mass spectrometer (TOF‐SIMs) depth profiling and transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Ordered TiO2 nanotube arrays of thickness 19 µm were formed by 2‐step anodization of titanium foil in an ethylene‐glycol‐based solution and a dip‐coating method was used to infiltrate the polymer into the TiO2 nanotubes. UV–Vis absorption spectrometer measurement of P3HT/TiO2 nanotubes shows a peak absorption at 500 nm due to embedded polymer within the nanotube arrays. TOF‐SIMs depth profiling up to 500 nm shows P3HT polymer is infiltrated into the TiO2 nanotube arrays. Furthermore, energy‐dispersive X‐ray spectroscopy (EDX) of the TEM indicates the presence of sulfur and carbon atoms due to the P3HT polymer. Polymer nanotubes can be observed with SEM after TiO2 nanotubes infiltrated with polymer are etched by dilute HF solution.