bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology, dynamic mechanical, and electrical properties of bio‐based poly(trimethylene terephthalate) blends, part 2: Poly(trimethylene terephthalate)/poly(ether esteramide)/polycarbonate blends
Authors: Kobayashi Toshikazu , Wood Barbara A. , Takemura Akio 
Published: August 2011

AbstractBio‐based poly(trimethylene terephthalate) (PTT) and poly(ether esteramide) (PEEA) blends were prepared by melt processing with varying weight ratios (0–20 wt %) of polycarbonate (PC). The blends were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polarized light microscopy (PLM), and transmission electron microscopy (TEM). Electrostatic performance was also investigated for those PTT blends since PEEA is known as an ion conductive polymer. DMA suggests that PC is miscible with PEEA and selectively goes into PEEA phase in case of ternary blends of PTT/PEEA/PC. The glass transition temperature (Tg) for PC/PEEA is well predicted by Gordon Taylor equation. Addition of PC retards the electrostatic decay performance of PTT/PEEA blends by restricting the motion of ions in PEEA through increasing the Tg of PEEA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of the MMA content on the emulsion polymerization process and adhesive properties of poly(BA‐co‐MMA‐co‐AA) latexes
Authors: Xu Hongping , Wang Nongyue , Qu Taoguang , Yang Jianguang , Yao Yanmei , Qu Xiongwei , Lovell Peter A. 
Published: August 2011

AbstractIn the past work, the shear resistance of pure poly(n‐butyl acrylate) was low, even incorporation of inorganic filler, silica in the composition. It is well‐known that the copolymerization of n‐butyl acrylate (BA) with methyl methacrylate (MMA) will increase the glass transition temperature, and enhance the shear resistance of acrylic polymers. In the current work, the preparation of a series of acrylic water‐borne pressure‐sensitive adhesives (PSAs) with the controlled composition and structure for the copolymerization of BA and acrylic acid (AA) with different MMA contents, poly(BA‐co‐MMA‐co‐AA) was reported and its effects on adhesive properties of the latices were investigated. The latices of poly(BA‐co‐MMA‐co‐AA) were prepared at a solid content of 50% by two‐stage sequential emulsion polymerization, and this process consisted of a batch seed stage giving a particle diameter of 111 nm, which was then grown by the semicontinuous addition of monomers to final diameter of 303 nm. Dynamic light scattering (DLS) was used to monitor the particle diameters and proved that no new nucleation occurred during the growth stage. Copolymerization of BA with MMA raised the glass transition temperature (Tg) of the soft acrylic polymers, and had the effect of improving shear resistance, while the loop tack and peel adhesion kept relatively high. The relationship between pressure‐sensitive properties and molecular parameters, such as gel content and molecular weight, was evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and properties of nano carboxylic acrylonitrile butadiene rubber latex toughened phenolic resin
Authors: Yu Zheng , Li Jingfeng , Yang Limin , Yao Yalin , Su Zhiqiang , Chen Xiaonong 
Published: August 2011

AbstractNano carboxylic acrylonitrile butadiene rubber latex‐toughened‐phenolic resins (XNBRL‐PF) were prepared by in situ polymerization in this work. The influence of nano XNBRL on the microstructure and physical properties of modified PF resin was investigated. Impact test testified that the impact strength of XNBRL‐PF was remarkably improved compared to pure PF and as the content of XNBRL increased to 10 wt %, the impact strength of the XNBRL‐PF kept increasing. Scanning electron microscope analysis of the fracture surface of the XNBRL‐PF indicated that the XNBRL were uniformly dispersed in the PF matrix, with diameters ranging from 200 to 400 nm. The results of Fourier transform infrared spectroscopy proved that chemical reaction occurred between XNBRL and PF matrix, which can greatly improve the interface interaction between rubber particles and PF matrix. Thermogravimetric analysis test showed that the incorporation of XNBRL can improve the thermostability of PF at low temperatures. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A polycarbonate/magnesium oxide nanocomposite with high flame retardancy
Authors: Dong Quanxiao , Gao Chong , Ding Yanfen , Wang Feng , Wen Bin , Zhang Shimin , Wang Tongxin , Yang Mingshu 
Published: August 2011

AbstractA new flame retardant polycarbonate/magnesium oxide (PC/MgO) nanocomposite, with high flame retardancy was developed by melt compounding. The effect of MgO to the flame retardancy, thermal property, and thermal degradation kinetics were investigated. Limited oxygen index (LOI) test revealed that a little amount of MgO (2 wt %) led to significant enhancement (LOI = 36.8) in flame retardancy. Thermogravimetric analysis results demonstrated that the onset temperature of degradation and temperature of maximum degradation rate decreased in both air and N2 atmosphere. Apparent activation energy was estimated via Flynn–Wall–Ozawa method. Three steps in the thermal degradation kinetics were observed after incorporation of MgO into the matrix and the additive raised activation energies of the composite in the full range except the initial stage. It was interpreted that the flame retardancy of PC was influenced by MgO through the following two aspects: on the one hand, MgO catalyzed the thermal‐oxidative degradation and accelerated a thermal protection/mass loss barrier at burning surface; on the other hand, the filler decreased activation energies in the initial step and improved thermal stability in the final period. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and thermal behavior of polymeric precursor for carbon‐free silicon oxynitride ceramic
Authors: Zhang Zongbo , Wang Rui , Wang Xiujun , Chen Li , Zhang Dahai , Luo Yongming , Xu Caihong 
Published: August 2011

AbstractA new polymeric precursor, perhydropolysiloxazane (PSNO), for silicon oxynitride (SiON) ceramic was synthesized by a simple one‐pot procedure involving partial hydrolysis of H2SiCl2 and the following ammonolysis reaction of the hydrolyzed intermediates with NH3. The structure of new polymer was characterized with perhydropolysiloxane (PHSO) and perhydropolysilazane (PHSN) as reference substances. The conversion of PSNO to ceramic was investigated by TGA, FT‐IR, and solid 29Si‐NMR analyses. A Si‐rich Si2N2O ceramic was produced upon pyrolysis of PSNO at 1400°C under N2 atmosphere. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermal conductivity and dynamic mechanical property of glycidyl methacrylate‐grafted multiwalled carbon nanotube/epoxy composites
Authors: Teng Chih‐Chun , Ma Chen‐Chi M. , Yang Shin‐Yi , Chiou Kuo‐Chan , Lee Tzong‐Ming , Chiang Chin‐Lung 
Published: August 2011

AbstractThe well dispersed multiwalled carbon nanotube (MWCNT)/epoxy composites were prepared by functionalization of the MWCNT surfaces with glycidyl methacrylate (GMA). The morphology and thermal properties of the epoxy nanocomposites were investigated and compared with the surface characteristics of MWCNTs. GMA‐grafted MWCNTs improved the dispersion and interfacial adhesion in epoxy resin, and enhanced the network structure. The storage modulus of 3 phr GMA‐MWCNTs/epoxy composites at 50°C increased from 0.32 GPa to 2.87 GPa (enhanced by 799%) and the increased tanδ from 50.5°C to 61.7°C (increased by 11.2°C) comparing with neat epoxy resin, respectively. Furthermore, the thermal conductivity of 3 phr GMA‐MWCNTs/epoxy composite is increased by 183%, from 0.2042 W/mK (neat epoxy) to 0.5781 W/mK. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fabrication of superhydrophobic fiber coatings by DC‐biased AC‐electrospinning
Authors: Ochanda Fredrick O. , Samaha Mohamed A. , Tafreshi Hooman Vahedi , Tepper Gary C. , Gad‐el‐Hak Mohamed 
Published: August 2011

AbstractMesh‐like fiber mats of polystyrene (PS) were deposited using DC‐biased AC‐electrospinning. Superhydrophobic surfaces with water contact angles greater than 150° and gas fraction values of up to 97% were obtained. Rheological study was conducted on these fiber surfaces and showed a decrease in shear stress when compared with a noncoated surface (no slip), making them excellent candidates for applications requiring the reduction of skin‐friction drag in submerged surfaces. We have also shown that addition of a second, low‐surface energy polymer to a solution of PS can be used to control the fiber internal porosity depending on the concentration of the second polymer. Contact‐angle measurements on mats consisting of porous and nonporous fibers have been used to evaluate the role of the larger spaces between the fibers and the pores on individual fibers on superhydrophobicity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Luminescent polydibenzothiophene thin film obtained by glow discharge method
Authors: Morales‐Corona Juan , López‐Barrera José A. , Avila‐Ortega Alejandro , Cruz Guillermo J. , Olayo María‐Guadalupe , Ortega‐López Mauricio , Vasquez‐Ortega Miguelina , Vazquez Humberto , Olayo Roberto 
Published: August 2011

AbstractThis work presents the synthesis by plasma and characterization of luminescent polymer thin films of dibenzothiophene (DBT) by plasma polymerization. The DBT is solid at room conditions and was sublimated and introduced to the plasma reactor to produce the chemical reactions with the vapors. The results indicated the production of polymers with benzene and thiophene rings in the structure as well as methylene groups. The polymer structure was studied by Fourier transform infrared spectroscopy and 13C‐CPMAS. The thermal analysis showed a residual mass of 60% at 800°C, which suggests a great thermal resilience in the polymer. The critical superficial tension was calculated with a Zisman plot and was 25 mN/m. The polymer has a fluorescent green emission between 400 and 660 nm and an orange emission between 660 and 850 nm. This effect can be a consequence of the electronic distribution along the structure in aliphatic and aromatic segments with benzene and thiophene rings. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A simulation method to analyze chemo‐mechanical behavior of swelling‐induced shape‐memory polymer in response to solvent
Authors: Lu Haibao 
Published: August 2011

AbstractA network of thermally responsive shape‐memory polymers (SMPs) could imbibe a quantity of solvent molecules to swell, and subsequently induces a chemical potential change in polymer. When an equilibrium is reached between the mechanical load and the chemical potential of polymer network and solvent, the SMP polymer usually swells with a field of inhomogeneous and anisotropic deformation, which is considered to be equivalent to a hyperelastic field. We implement this theory in the free‐energy function equation, and analyze examples of swelling‐induced deformation and shape recovery behavior. This work may provide a powerful tool to study complex swelling‐induced shape‐memory behavior of SMPs in response to the immersing solvents. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Tailoring the optical and thermomechanical properties of polymer host–guest systems
Authors: Hanemann Thomas , Honnef Kirsten 
Published: August 2011

AbstractFor modern applications in microoptics, the refractive index (n) of polymers can be adjusted in a certain range by the addition of electron‐rich organic dopants. As an unwanted side effect, a pronounced plasticizing occurs. In this work, the addition of a crosslinker (divinylbenzene) to an unsaturated polyester matrix, doped with phenanthrene for n adjustment, allowed us to successfully suppress the plasticizing effect measured after polymerization. Even at high phenanthrene concentrations, the glass‐transition temperature of the initial polymer could be almost retained. An increase of the polymer n from 1.5684 to a value of 1.6425 was achieved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Stable and high‐level production of recombinant Factor IX in human hepatic cell line
Authors: de Castilho Fernandes Andrielle , Fontes Aparecida , Gonsales Nathalia , Swiech Kamilla , Picanco‐Castro Virginia , Faca Sandra , Covas Dimas 
Published: August 2011

AbstractHemophilia B is a genetic disease of the coagulation system that affects one in 30,000 males worldwide. Recombinant human Factor IX (rhFIX) has been used for hemophilia B treatment, but the amount of active protein generated by these systems is inefficient, resulting in a high‐cost production of rhFIX. In this study, we developed an alternative for rhFIX production. We used a retrovirus system to obtain two recombinant cell lines. We first tested rhFIX production in the human embryonic kidney 293 cells (293). Next, we tested a hepatic cell line (HepG2) because FIX is primarily expressed in the liver. Our results reveal that intracellular rhFIX expression was more efficient in HepG2/rhFIX (46%) than in 293/rhFIX (21%). The activated partial thromboplastin time test showed that HepG2/rhFIX expressed biologically active rhFIX 1.5 times higher than 293/rhFIX (P = 0.016). Recovery of rhFIX from the HepG2 by reversed‐phase chromatography was straightforward. We found that rhFIX has a pharmacokinetic profile similar to that of FIX purified from human plasma when tested in hemophilic B model. HepG2/rhFIX cell line produced the highest levels of rhFIX, representing an efficient in vitro expression system. This work opens up the possibility of significantly reducing the costs of rhFIX production, with implications for expanding hemophilia B treatment in developing countries.
Running on empty: Does mitochondrial DNA mutation limit replicative lifespan in yeast?
Authors: Dunn Cory D. 
Published: August 2011

AbstractMitochondrial DNA (mtDNA) mutations escalate with increasing age in higher organisms. However, it has so far been difficult to experimentally determine whether mtDNA mutation merely correlates with age or directly limits lifespan. A recent study shows that budding yeast can also lose functional mtDNA late in life. Interestingly, independent studies of replicative lifespan (RLS) and of mtDNA‐deficient cells show that the same mutations can increase both RLS and the division rate of yeast lacking the mitochondrial genome. These exciting, parallel findings imply a potential causal relationship between mtDNA mutation and replicative senescence. Furthermore, these results suggest more efficient methods for discovering genes that determine lifespan.
Flow‐injection chemiluminescence determination of melamine in urine and plasma
Authors: Tang Xiaoshuang , Shi Xiyan , Tang Yuhai , Yue Zhongjin , He Qiqi 
Published: August 2011

ABSTRACTA novel flow‐injection chemiluminescence method for the determination of melamine in urine and plasma was developed. It was found that melamine can remarkably enhance chemiluminescence emission from the luminol–K3Fe(CN)6 system in an alkaline medium. Under the optimum conditions, chemiluminescence intensity had a good linear relationship with the concentration of melamine in the range 9.0 × 10–9–7.0 × 10–6 g/mL, with a correlation coefficient of 0.9992. The detection limit (3σ) was 3.5 ng/mL. The method has been applied to determine the concentration of melamine in samples using liquid–liquid extraction. Average recoveries of melamine were 102.6% in urine samples and 95.1% in plasma samples. The method provided a reproducible and stable approach for the sensitive detection of melamine in urine and plasma samples. Copyright © 2011 John Wiley & Sons, Ltd.
Structure of micelle‐bound adrenomedullin: A first step toward the analysis of its interactions with receptors and small molecules
Authors: Pérez‐Castells Javier , Martín‐Santamaría Sonsoles , Nieto Lidia , Ramos Ana , Martínez Alfredo , Pascual‐Teresa Beatriz de , Jiménez‐Barbero Jesús 
Published: August 2011

AbstractAdrenomedullin (AM) is a regulatory peptide which plays many physiological roles including vasodilatation, bronchodilatation, hormone secretion regulation, growth, apoptosis, angiogenesis, and antimicrobial activities, among others. These regulatory activities make AM a relevant player in the pathophysiology of important diseases such as cardiovascular and renal conditions, cancer, and diabetes. Therefore, molecules that target the AM system have been proposed as having therapeutic potential. To guide the design and characterization of such molecules, we elucidated the three‐dimensional structure of AM in a membrane mimicking medium using NMR spectroscopy methods. Under the employed experimental conditions, the structure can be described as composed by a central α‐helical region, spanning about one third of its total length, flanked by two disordered segments at both N‐ and C‐termini. The structure of AM in water is completely disordered. The 22–34 region of AM has a general tendency to adopt a helical structure under the employed experimental conditions. Furthermore, the study of the interaction of AM with two of its modulators has also been performed by using chemical shift perturbation analysis NMR methods with two‐dimensional (2D)‐TOCSY experiments, assisted with molecular modeling protocols. We expect these results will help in better understanding the interactions of AM with its receptor and binding proteins/molecules and in the development of novel modulators of AM activities. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 45–53, 2012.
Extrusion based rapid prototyping technique: An advanced platform for tissue engineering scaffold fabrication
Authors: Hoque M. Enamul , Chuan Y. Leng , Pashby Ian 
Published: August 2011

AbstractAdvances in scaffold design and fabrication technology have brought the tissue engineering field stepping into a new era. Conventional techniques used to develop scaffolds inherit limitations, such as lack of control over the pore morphology and architecture as well as reproducibility. Rapid prototyping (RP) technology, a layer‐by‐layer additive approach offers a unique opportunity to build complex 3D architectures overcoming those limitations that could ultimately be tailored to cater for patient‐specific applications. Using RP methods, researchers have been able to customize scaffolds to mimic the biomechanical properties (in terms of structural integrity, strength, and microenvironment) of the organ or tissue to be repaired/replaced quite closely. This article provides intensive description on various extrusion based scaffold fabrication techniques and review their potential utility for TE applications. The extrusion‐based technique extrudes the molten polymer as a thin filament through a nozzle onto a platform layer‐by‐layer and thus building 3D scaffold. The technique allows full control over pore architecture and dimension in the x‐ and y‐ planes. However, the pore height in z‐direction is predetermined by the extruding nozzle diameter rather than the technique itself. This review attempts to assess the current state and future prospects of this technology. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 83–93, 2012.
Application of a novel thermostable NAD(P)H oxidase from hyperthermophilic archaeon for the regeneration of both NAD+ and NADP+
Authors: Wu Xi , Kobori Hiroki , Orita Izumi , Zhang Chong , Imanaka Tadayuki , Xing Xin‐Hui , Fukui Toshiaki 
Published: August 2011

AbstractA novel thermostable NAD(P)H oxidase from the hyperthermophilic archaeon Thermococcus kodakarensis KOD1 (TkNOX) catalyzes oxidation of NADH and NADPH with oxygen from atmospheric air as an electron acceptor. Although the optimal temperature of TkNOX is >90°C, it also shows activity at 30°C. This enzyme was used for the regeneration of both NADP+ and NAD+ in alcohol dehydrogenase (ADH)‐catalyzed enantioselective oxidation of racemic 1‐phenylethanol. NADP+ regeneration at 30°C was performed by TkNOX coupled with (R)‐specific ADH from Lactobacillus kefir, resulting in successful acquisition of optically pure (S)‐1‐phenylethanol. The use of TkNOX with moderately thermostable (S)‐specific ADH from Rhodococcus erythropolis enabled us to operate the enantioselective bioconversion accompanying NAD+ regeneration at high temperatures. Optically pure (R)‐1‐phenylethanol was successfully obtained by this system after a shorter reaction time at 45–60°C than that at 30°C, demonstrating an advantage of the combination of thermostable enzymes. The ability of TkNOX to oxidize both NADH and NADPH with remarkable thermostability renders this enzyme a versatile tool for regeneration of the oxidized nicotinamide cofactors without the need for extra substrates other than dissolved oxygen from air. Biotechnol. Bioeng. 2012;109: 53–62. © 2011 Wiley Periodicals, Inc.
Construction of a recombinant Trichoderma reesei strain expressing Aspergillus aculeatus β‐glucosidase 1 for efficient biomass conversion
Authors: Nakazawa Hikaru , Kawai Tetsushi , Ida Noriko , Shida Yosuke , Kobayashi Yoshinori , Okada Hirofumi , Tani Shuji , Sumitani Jun‐ichi , Kawaguchi Takashi , Morikawa Yasushi , Ogasawara Wataru 
Published: August 2011

AbstractTo develop a Trichoderma reesei strain appropriate for the saccharification of pretreated cellulosic biomass, a recombinant T. reesei strain, X3AB1, was constructed that expressed an Aspergillus aculeatus β‐glucosidase 1 with high specific activity under the control of the xyn3 promoter. The culture supernatant from T. reesei X3AB1 grown on 1% Avicel as a carbon source had 63‐ and 25‐fold higher β‐glucosidase activity against cellobiose compared to that of the parent strain PC‐3‐7 and that of the T. reesei recombinant strain expressing an endogenous β‐glucosidase I, respectively. Further, the xylanase activity was 30% lower than that of PC‐3‐7 due to the absence of xyn3. X3AB1 grown on 1% Avicel‐0.5% xylan medium produced 2.3‐ and 3.3‐fold more xylanase and β‐xylosidase, respectively, than X3AB1 grown on 1% Avicel. The supernatant from X3AB1 grown on Avicel and xylan saccharified NaOH‐pretreated rice straw efficiently at a low enzyme dose, indicating that the strain has good potential for use in cellulosic biomass conversion processes. Biotechnol. Bioeng. 2012;109: 92–99. © 2011 Wiley Periodicals, Inc.
Simultaneous determination of lidamycin enediyne chromophore (LDC) and its aromatized derivative (LDCA) using puerarin as internal standard in rat plasma by LC‐MS/MS
Authors: Wen Yanqing , Chen Shuzhen , Meng Zhiyun , Gan Hui , Zhu Xiaoxia , Wu Zhuona , Gu Ruolan , Dou GuiFang 
Published: August 2011

ABSTRACTLidamycin (LDM), a promising enediyne antitumor antibiotic, was quantified by detecting lidamycin enediyne chromophore (LDC) using liquid chromatography–tandem mass spectrometry (LC‐MS/MS) for the first time. A simple, rapid and reliable method was developed and validated to determine LDC and its aromatized derivative (LDCA) simultaneously in plasma. Puerarin was used as an internal standard (IS), and plasma samples were pretreated with one‐step precipitation by acetonitrile. Separation was achieved on a reverse‐phase C18 column with a mobile phase composed of methanol and water containing 5 mm ammonium acetate at pH 3.5 in gradient elution mode. Detection was performed on a triple quadrupole tandem mass spectrometer using electrospray ionization (ESI) by multiple reaction monitoring (MRM) in the negative ion mode. Good linearity was obtained over the concentration range of 0.2–100 µg/mL for LDM. Precision and accuracy were validated by RSD% values in the range of 2.6–13.0% and RE% values between −4.6 and 3.8%, respectively. In addition, no specificity and matrix effects were observed. The recovery was found to be 99.2–111.0% and stability in various conditions was found to be acceptable. This method was applied in preclinical pharmacokinetic studies for routine monitoring of LDM in rat plasma. Copyright © 2011 John Wiley & Sons, Ltd.