bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and characterization of γ‐irradiated crosslinked silicone rubber/organoattapulgite composites
Authors: Song Lei , Fang Shoulin , Zhan Jing , Hu Yuan , Wu Jing 
Published: April 2009

AbstractSilicone rubber (SR)/organoattapulgite (OAT) composites were prepared with γ‐irradiation crosslinking at a dose range varied from 30 to 300 kGy. Natural fibrillar silicate attapulgite (AT) was modified by silane coupling agent, and the obtained OAT was used as reinforcing fillers in SR. The effect of irradiation doses on the degree of crosslinking of SR/OAT composites was determined by solvent swelling method. It was found that the molecular weight between crosslinks (Mc) reduced with the increase in irradiation doses. Moreover, the addition of OAT to SR matrix promoted an increase in the crosslinking density of the composites because of the presence of the active crosslinking sites of OAT. The mechanical properties of the SR/OAT composites including tensile strength, elongation at break, and Shore A hardness subjected to various irradiation doses were studied. The experimental results showed that the tensile strength, elongation at break, and Shore A hardness were all improved significantly in the presence of OAT, which indicated that OAT was an alternative reinforcing filler of SR. In addition, the effect of various irradiation doses on the mechanical properties of SR and SR/OAT composites was also investigated. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Characterization of interlaminar shear strength of laminated woven E‐glass/epoxy composites by four point bend shear test
Authors: Aslan Züleyha , Alnak Yeliz 
Published: April 2009

AbstractAn experimental and numerical investigation was performed to study the interlaminar shear response of laminated woven E‐glass/epoxy composites. The interlaminar shear strength results obtained from four point bend shear tests were compared with the results obtained from American Society for Testing and Materials (ASTM) test standards D2344 (short beam strength). The test results reveal that the four point bend interlaminar shear test results at a span to thickness ratio of 8 is higher than the short beam shear test results at a span to thickness ratio of 4. Numerical simulations were performed with ANSYS® software. The experimental results and the corresponding numerical results are in good agreement. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Structure and properties of multi‐walled carbon nanotubes/polyethylene nanocomposites synthesized by in situ polymerization with supported Cp2ZrCl2 catalyst
Authors: Li Shiyun , Chen Hui , Cui Dongmei , Li Jianzhong , Zhang Zhenjiang , Wang Yanhui , Tang Tao 
Published: April 2009

AbstractMulti‐walled carbon nanotubes (MWCNTs)/polyethylene (PE) nanocomposites were prepared via in situ polymerization with MWCNTs supported Bis‐ (cyclopentadienyl) zirconium dichloride (Cp2ZrCl2) catalyst. X‐ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FESEM) results implied that Cp2ZrCl2 catalyst was immobilized in the surface of the MWCNTs supports via a bridge of methylaluminoxane (MAO). The efficient dispersion of MWCNTs in PE matrix and the strong compressive forces associated with PE on the MWCNTs were demonstrated by means of transmission electron microscope (TEM), FESEM and Raman spectra. With introducing 0.2 wt% MWCNTs, both the tensile strength and elongation of MWCNTs/PE nanocomposite were improved by factors of 1.6 (from 29 to 45 MPa) and 1.5 (from 909% to 1360%) comparing with the pure PE, respectively. Morphology observation of fractured surface revealed that the PE firmly adhered to the nanotubes, which was responsible for the significant improvement of the mechanical properties of nanocomposites. Thermal stabilities of the nanocomposites were significantly improved. In addition, the MWCNTs/PE nanocomposites showed very high ultraviolet (UV) shielding property, which could increase photooxidative stability of the PE. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Melt compounding of PMMA/clay nanocomposites with styrene‐maleic anhydride copolymers: Effect of copolymer type on thermal, mechanical and dielectric properties
Authors: Wang Yeh , Guo Jiang‐Y. 
Published: April 2009

AbstractPoly(methyl methacrylate) (PMMA)‐clay nanocomposites (PCN) were prepared through melt blending. Styrene‐maleic anhydride copolymers (SMA) of different molecular weights and MA contents were used as compatibilizers with organically modified clay. The melt‐blended PCN materials were subsequently investigated by a series of characterization techniques, including wide‐angle X‐ray diffraction, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and thermal mechanical analysis. Compared with unmodified PMMA, with only 5 wt% clay loading, the modified PCN materials exhibit higher glass‐transition temperatures, higher dynamic storage moduli, and lower thermal expansion coefficients. The dielectric properties of PCNs in plate form were measured with dielectric spectroscopy. Significant increase in dielectric permitivities and losses were observed for these PCNs. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Evaluation of tribological properties of carbon fiber‐reinforced PA6 composites
Authors: Li J. , Xia Y.C. 
Published: April 2009

AbstractThe tribological performance of PA6 and carbon fiber‐reinforced polyamide 6 (CF/PA6) under dry sliding condition was examined. Different contents of carbon fibers were employed as reinforcement. All filled and unfilled polyamide 6 composites were tested against CGr15 ball and representative testing was performed. The effects of carbon fiber content on tribological properties of the composites were investigated. The worn surface morphologies of neat PA6 and its composites were examined by scanning electron microscopy and the wear mechanisms were discussed. Moreover, all filled polyamide 6 have superior tribological characteristics to unfilled polyamides 6. The optimum wear reduction was obtained when the content of carbon fiber is 20 vol%. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Published versus unpublished dissertations in psycho‐oncology intervention research
Authors: Moyer Anne , Schneider Stefan , Knapp‐Oliver Sarah K. , Sohl Stephanie J. 
Published: April 2009

AbstractObjective: There are conflicting views regarding whether gray literature, including unpublished doctoral dissertations, should be included in systematic reviews and meta‐analyses. Although publication status frequently is used as a proxy for study quality, some research suggests that dissertations are often of superior quality to published studies.Methods: We examined 107 projects involving doctoral dissertations (42 published, 65 unpublished) that studied psychosocial interventions for cancer patients.Results: Published dissertations were more likely to be supported by research funding but were not more likely than unpublished dissertations to examine specific types of interventions. Across several indices of methodological quality there were minimal differences. Dissertations with significant findings tended to be more likely to be published than those without significant findings.Conclusions: Unpublished dissertations focusing on psychosocial interventions for cancer patients are not necessarily of vastly inferior quality to those that eventually are published. Because doctoral dissertations are easy to access relative to other forms of gray literature, are free from some types of bias, and are reported thoroughly, they merit inclusion in comprehensive literature reviews. Copyright © 2009 John Wiley & Sons, Ltd.
Listeriolysin O as cytotoxic component of an immunotoxin
Authors: Bergelt Sabine , Frost Stefan , Lilie Hauke 
Published: April 2009

AbstractMonoclonal antibodies (mAbs) have been developed over the past years as promising anticancer therapeutics. The conjugation of tumor specific mAbs with cytotoxic molecules has been shown to improve their efficacy dramatically. These bifunctional immunotoxins, consisting of covalently linked antibodies and protein toxins, possess considerable potential in cancer therapy. Many of them are under investigation in clinical trials. As a result of general interest in new toxic components, we describe here the suitability of the bacterial protein Listeriolysin O (LLO) as cytotoxic component of an immunotoxin. Unique characteristics of LLO, such as its acidic pH optimum and the possibility to regulate the cytolytic activity by cysteine‐oxidation, make LLO an interesting toxophore. Oxidized LLO shows a substantially decreased cytolytic activity when compared with the reduced protein as analyzed by hemolysis. Both oxidized and reduced LLO exhibit a cell‐type‐unspecific toxicity in cell culture with a significantly higher toxicity of reduced LLO. For cell‐type‐specific targeting of LLO to tumor cells, LLO was coupled to the dsFv fragment of the monoclonal antibody B3, which recognizes the tumor‐antigen Lewis Y. The coupling of LLO to dsFv‐B3 was performed via cysteine‐containing polyionic fusion peptides that act as a specific heterodimerization motif. The novel immunotoxin B3‐LLO could be shown to specifically eliminate antigen positive MCF7 cells with an EC50value of 2.3 nM, whereas antigen negative cell lines were 80‐ to 250‐fold less sensitive towards B3‐LLO.
Green fluorescence induced by EF‐hand assembly in a split GFP system
Authors: Lindman Stina , Johansson Ida , Thulin Eva , Linse Sara 
Published: April 2009

AbstractThe affinity between the 1–157 and 158–238 fragments of green fluorescent protein (GFP) is too low for spontaneous in vivo reassembly of the protein upon co‐expression of the two fragments. This prevents chromophore maturation and the cells lack GFP fluorescence. We have utilized the very high affinity between the two EF‐hands of calbindin D9k to facilitate GFP assembly from its fragments and to introduce a calcium dependent molecular switch. In GFPN‐EF1, residues 1–157 of GFP are fused to residues 1–43 of calbindin, and in EF2‐GFPC, residues 44–75 of calbindin are fused to residues 158–238 of GFP. When co‐expressed, GFPN‐EF1 and EF2‐GFPC associate spontaneously and rapidly resulting in a folded reconstituted protein with bright GFP fluorescence. The high affinity of GFPN‐EF1 for EF2‐GFPC leads to brighter fluorescence of the cells compared to cells with a control constructs carrying leucine zippers (Wilson et al., Nature Methods 2004;3:255). The complex of GFPN‐EF1 and EF2‐GFPC was purified from cells using metal‐ion chelate chromatography and the temperature dependence of GFP fluorescence was found to be calcium dependent. The GFPN‐EF1 and EF2‐GFPC fragments were separated by ion exchange chromatography. The assembly of the fragments was found to be reversible and the complex was regained upon mixing, as evidenced by surface plasmon resonance (SPR) data. The affinity between GFPN‐EF1 and EF2‐GFPC as well as rates of association and dissociation were found to be Ca2+‐dependent.
Identification of µ‐crystallin as an androgen‐regulated gene in human prostate cancer
Authors: Malinowska Kamilla , Cavarretta Ilaria T. , Susani Martin , Wrulich Oliver A. , Überall Florian , Kenner Lukas , Culig Zoran 
Published: April 2009

AbstractBACKGROUNDAndrogen receptor (AR) signaling is implicated in prostate cancer progression. Therefore, identification of AR downstream genes is potentially important for selection of novel markers and therapy targets in prostate cancer.METHODSExpression of a thyroid hormone T3‐binding protein µ‐crystallin (CRYM) mRNA and protein in cell lines was evaluated by real‐time PCR and Western blot, respectively. CRYM expression in vivo was analyzed in patients' samples by immunohistochemistry. The effects of androgen and T3 on proliferation of MDA PCa 2b cells were assessed by 3H‐thymidine uptake assay.RESULTSCRYM expression was detected in AR‐positive LNCaP and MDA PCa 2b cells. In MDA PCA 2b cells, CRYM was regulated by androgens. Androgen‐induced CRYM expression was diminished by antiandrogens or AR siRNA. Inhibition of transcription by α‐amanitin caused a reduction in CRYM mRNA. The lack of CRYM expression was noted in LAPC‐4 cells and in AR‐negative prostate cancer cell lines PC‐3 and DU‐145. CRYM protein was increased in cancer tissue and decreased in samples from patients after hormonal therapy. In samples from patients with therapy‐refractory cancer CRYM was not detectable. We also found that androgens and T3 have additive effects on stimulation of MDA PCa 2b cells proliferation.CONCLUSIONCRYM is a novel androgen‐regulated gene whose expression is elevated in prostate cancer but down‐regulated in castration therapy‐resistant tumors. Prostate 69:1109–1118, 2009. © 2009 Wiley‐Liss, Inc.
Structure and optical properties of non‐doped and N‐doped ZnO films with non‐polar surfaces grown homoepitaxially on single crystal ZnO (11$ \bar 2 $0) substrates
Authors: Abe Takami , Nakagawa A. , Chiba S. , Kashiwaba Y. , Endo H. , Meguro K. , Ojima T. , Aota K. , Daibo M. , Osada H. , Niikura I. , Kashiwaba Y. , Fujiwara T. 
Published: April 2009

AbstractNon‐doped ZnO films and nitrogen‐doped ZnO films (ZnO:N films) were grown epitaxially on non‐polar single crystal ZnO (11$ \bar 2 $0) substrates by using the plasma‐assisted reactive evaporation (PARE) method. The value of FWHM of the ω‐scan rocking curve of non‐doped ZnO (11$ \bar 2 $0) films were 26 to 62 arcseconds. Crystallinity of ZnO (11$ \bar 2 $0) films deteriorated with increase in N2 gas flow rate, but crystallinity of the films was better than that of ZnO (11$ \bar 2 $0) films grown on sapphire (11$ \bar 2 $0) substrates by the PARE method. Independently of N2 gas flow rate, AFM images of non‐polar ZnO films showed a smooth surface with about 1 nm of root mean square roughness. In near band‐edge PL spectra from these non‐doped ZnO films measured at 5 K, free‐exciton emission (FE) at about 3.378 eV, ionized‐donor‐bound excitons (D+X) at about 3.368 eV and neutral‐donor‐bound excitons (D0X) at about 3.362 eV were clearly observed. PL intensity of D+X of non‐polar ZnO:N films was decreased but that of donor‐acceptor pairs (DAP) emission at around 3.308 eV of the films increased with an increase in N2 gas flow rate. It is thought that N atoms occupied oxygen sites and surface state density were decreased with increase in N2 gas flow rate and that N atoms act as acceptors in ZnO. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic and thermal properties of magnesium‐doped a‐Se films
Authors: Dash Isha , Tonchev Dan , Belev George , Mani Habib , Kasap Safa 
Published: April 2009

AbstractWe have studied the effects of adding small amounts of Mg on the electrical and thermal properties of a‐Se films. The addition of Mg in the ppm range has resulted in significant changes in the charge transport and stability. The doped samples have shown to be excellent n ‐like layers which have electron ranges much greater than hole ranges, μeτe ≫ μhτh. The n ‐like layers block the injection of holes from the positive electrode which results in a lower dark current in a‐Se based X‐ray detectors. The Differential scanning calorimetry studies have shown that a‐Se doped with lower concentrations of Mg is more stable than samples with higher concentrations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopy properties and energy level location of Gd2O2S:Pr3+,Ce3+
Authors: Cebim Marco Aurélio , Silva Alison Abreu Da , Davolos Marian Rosaly 
Published: April 2009

AbstractIn this work we propose the study of the spectroscopy properties and the energy level location of Ce3+ and Pr3+ in Gd2O2S, along with the effects of Ce4+ (Ce2O2S2) incorporation in Gd2O2S and Gd2O2S:Pr3+ in order to understand the formation and position of the associated defects energy levels in relation to the band structure of Gd2O2S and Pr3+ energy levels. Ce‐, Pr3+‐doped and Pr3+,Ce‐doped Gd2O2S were prepared by the sulfidization of a basic gadolinium carbonate with S8 using H2/N2 (3.0/97.0%) and air during the firing of the precursor. Samples were analyzed by X‐ray diffraction in order to guarantee the formation of the Gd2O2S single phase. Diffuse reflectance spectroscopy and luminescent measurements (emission/excitation) were used to locate Ce3+, Pr3+ and defects energy levels in relation to the band structure of Gd2O2S. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface enhanced Raman scattering of amino acids and peptides
Authors: Kandakkathara Archana , Utkin Ilya , Fedosejevs Robert 
Published: April 2009

AbstractSurface Enhanced Raman Scattering (SERS) has been used to observe spectra of several amino acids and peptides. SERS signals from amino acids (tryptophan, phenylalanine and glycine) and peptides (Trp‐Trp and Gly‐Gly‐Gly) in silver colloids have been studied in three experimental configurations 1) free volume 2) liquid core waveguide (LCW) and 3) microfluidic channel. Even though all amino acids contain carboxyl and amine functional groups, the conditions for observing the SERS spectra are different for different amino acids. The impact of the type of electrolyte used for colloid aggregation and the experimental procedures for mixing of the components on the amplitude and the stability of the SERS signal have been studied. The optimum conditions for observing SERS signals for the above mentioned amino acids and peptides have been found. For Trp amino acid a SERS enhancement of Raman signal up to 107 was observed. Additional enhancement of 10 to 50 times can be obtained with the help of a liquid core waveguide technique. The results obtained will be useful in the development and optimization of microfluidic chip devices utilizing SERS. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal tuning of planar Bragg gratings in silicon‐on‐insulator rib waveguides
Authors: Homampour Shabnam , Bulk Michael P. , Jessop Paul E. , Knights Andrew P. 
Published: April 2009

AbstractThe Bragg grating forms an essential element in optical telecommunication and sensing applications. In the case of integrated optics, it is necessary to incorporate the grating into a waveguide during device fabrication. Specifically for silicon photonics this process is deemed necessary to be compatible with standard processing technology. We have recently developed a method for the fabrication of Bragg gratings via self‐ion implantation of silicon‐on‐insulator (SOI) waveguides, such that the surface of the waveguide remains planar. This has significant benefits for a number of devices especially those requiring subsequent wafer bonding. Here we report work that shows the ability of these devices to be thermally tuned. As the waveguides are heated, a positive shift in the resonant wavelength is induced due to the temperature dependence of the index of refraction and thermal expansion of the silicon. The observed shift is 0.080 nm/degree, in good agreement with theoretical prediction. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence properties of erbium‐doped amorphous gallium‐germanium‐selenium films fabricated by RF sputtering
Authors: Imai Takahiko , Maeda Kouji , Fujita Masahiro , Saito Nobuo 
Published: April 2009

AbstractChalcogenide glasses have various useful features for optical devices such as a high refractive index, low‐loss transmission in the mid‐IR, and low phonon energies. The fabrication of thin films is important for use in waveguide applications and integrated photonics. In this work, we report the properties of vacuum deposited films of gallium‐germanium‐selenium glasses onto fused silica substrates by an RF magnetron sputtering technique (RF electric power of 40‐250 W and growth rate of 0.01‐2.1 μm/min). The concentration of Er3+ ions is controlled by the number of sintered Er2S3 small plates on a target. Samples are shown to be in an amorphous‐like state as measured by X‐ray diffraction experiments. Film thicknesses are proportional to the RF sputtering power and sputtering time. The compositions of films obtained from energy dispersive X‐ray (EDX) analysis. There are much dependent on the condition of the sputtering target, for example whether the target is in the bulk or powder‐state. Photoluminescence (PL) spectrum, intensity, and lifetime at 1550 nm band are measured by excitation from a 973 nm laser. The PL band of the films has a similar shape to those of bulk glasses. The PL intensity increased with the RF electric power. The PL lifetime at the 1550 nm band of the film is about 1.8‐2.6 ms; the latter values are similar to those of bulk samples. The results show that the RF sputtering is a potential method of fabrication for Er‐doped GeGaSe thin films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New phosphinate ligand synthesis and its effect on optical properties of the europium β‐diketonate complex
Authors: Adati Renata Danielle , Davolos Marian Rosaly , Jafelicci Miguel , Lima Sergio Antonio Marques , Viegas Cláudio 
Published: April 2009

AbstractThe synthesis and characterization of a new organic ligand monooctyldiphenylphosphinate (L) is described, as well as a new Eu3+ diketonate complex [Eu(tta)3(L)2] (tta = thenoyltrifluoracetone). The ligand (L) was formed by substitution reaction (80% yield) and characterized by uni‐ and bi‐dimensional 1H, 13C and 31P NMR experiments, to confirm its molecular structure. The coordination of (L) to Eu3+ in the complex [Eu(tta)3(L)2] was confirmed by FT‐IR spectra. The emission spectra present the same profile when excited in Eu3+ or in the ligands, suggesting an energy transfer from ligands to Eu3+ ions. The emission spectra of the precursor [Eu(tta)3(H2O)2], and [Eu(tta)3(L2)] present bands arising from f‐f intra‐configurational transitions.The only 5D0‐7F0 transition shows the presence of at least one site without symmetry center. The FWHM of such transition is 7 cm–1 and 57 cm–1 for [Eu(tta)3(H2O)2] and [Eu(tta)3(L)2] complexes, respectively. This widening is provided by the presence of large groups around Eu3+ ion. The calculated intensity parameters Ω2 and Ω4 show that the interaction features between center‐ion and ligand are different; the small value of Ω4 is related to long range effects of alkyl chain. The Langmuir isotherms of this ligand and complex have been investigated although their hydrolysis in water subphase does not allow stable monolayers (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrafast coherent vibronic oscillations in regioregular poly(3‐alkylthiophene)
Authors: Kanemoto Katsuichi , Sugisaki Mitsuru , Fujiwara Masazumi , Karasawa Tsutomu , Hashimoto Hideki 
Published: April 2009

AbstractUltrafast degenerate four‐wave mixing (DFWM) signals of the regioregular (RR) poly(3‐hexylthiophene) (P3HT) film have been investigated by the experiments using sub‐20 fs pulses generated from a noncollinear optical parametric amplifier (NOPA) system. Strong DFWM signals were observed owing to a large third‐order nonlinear susceptibility χ(3) of the RR‐P3HT film. The time profile of the DFWM signals exhibits clear coherent oscillation on a decaying signal. The oscillation turn out to be caused by the C=C stretching mode that gives strong Raman signal. The time profile of the DFWM signal is simulated by a numerical calculation. The result of simulation reveals that decay constants of electronic population and of vibronic oscillation are 200 fs and 210 fs, respectively. This is the first determination of the decay constants for the RR‐P3HT film. The obtained result demonstrates that the χ(3) signal of the RR‐P3HT film decays very rapidly. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)