bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microwave‐induced degradation of nitrosamines trapped in zeolites
Authors: Xu Jia Hui , Zhou Yu , Wen Jing Jia , Wu Zheng Ying , Zhou Chun Fang , Zhu Jian Hua 
Published: July 2008

AbstractA new method is reported for the degradation of nitrosamines trapped by zeolites. Significant amount of N‐nitrosodiphenylamine (NDPA) in dichloromethane solution, up to one‐third, could be degraded by microwave within 1 min once they were adsorbed by zeolite. The nitrosamine molecule, resulting from the electrostatic interaction between the NNO group of NDPA and the cation of zeolite, could be partially anchored inside the channel of zeolite depending on the degree of structure matching between the adsorbent and the adsorbate. Anchoring of nitrosamines limited their movement so that they were degraded by microwave irradiation. Mesoporous SBA‐15 and amorphous silica in solution could also promote the microwave‐induced degradation of NDPA, owing to the interaction between the surface SiOH and the NNO group of NDPA, and introducing copper oxide increased the conversion of NDPA. In addition, the influence of pore structure of zeolite on the microwave‐induced degradation of volatile nitrosamines was examined and discussed, and NaA exhibits a stronger adsorption than NaY for N‐nitrosopyrrolidine (NPYR). Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Synthesis and characterization of 2‐oxazoline‐benzoxazine compound and its polymer
Authors: Cao Hongwei , Xu Riwei , Yu Dingsheng 
Published: July 2008

AbstractA novel 2‐oxazoline‐benzoxazine (POB) was synthesized with 2‐(hydroxylphenyl)‐2‐oxazoline, 1,3,5‐triphenylhexahydro‐1,3,5‐triazine and paraformaldehyde. The chemical structure of the monomer was confirmed by FTIR, 1H‐NMR, 13C‐NMR, and MS. The curing behavior of the monomer was studied by DSC and FTIR, and the ring opening reaction of the monomer was found to occur from 187.5°C. The results of DMA and TGA demonstrated that the thermal properties of polymer for POB monomer (P‐m) are better than polymer for POB precursor (P‐p), because that the oligomer in benzoxazine precursor decreased the perfection of the polymer's network structure; it was also found that the thermal properties of P‐m and P‐p are much better than the common polybenzoxazine and the composite material of benzoxazine and 2‐oxazoline. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci	, 2008.
Poly(ethylene terephthalate)/attapulgite nanocomposites: Preparation, structure, and properties
Authors: Yao Xiayin , Tian Xingyou , Zhang Xian , Zheng Kang , Zheng Jin , Zhang Haobin , Chen Lin , Li Yong , Cui Ping 
Published: July 2008

AbstractIn this study, poly(ethylene terephthalate) (PET)/attapulgite (AT) nanocomposites were prepared through the in situ polymerization of terephthalic acid, ethylene glycol, and AT, which was not premodified. By means of this new method, PET chains were successfully grafted onto the surface of AT, and this was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Transmission electron microscopy micrographs revealed that AT was well dispersed in the PET matrix. Differential scanning calorimetry and thermogravimetric analysis were used to investigate the thermal properties of the nanocomposites. The results suggested that the addition of AT could accelerate the crystallization rate and enhance the thermal stability of PET. Dynamic mechanical analysis results showed that the storage modulus of the PET/AT nanocomposites was greatly improved in comparison with that of pure PET. The tensile strength and modulus increased with increasing AT content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Influence of morphology on the dynamic mechanical properties of hydrogenated acrylonitrile butadiene elastomer/coagent nanodispersions
Authors: Likozar Blaž , Krajnc Matjaž 
Published: July 2008

AbstractCoagents are vinyl monomers that react with free radicals formed by peroxide dissociation and are either grafted to elastomer chains or homopolymerized within a segregated phase to form a crosslinked network. The initial phase distribution within the elastomer matrix is of great importance for the final user properties of a composite material. In this study, the morphology of blends of each of three different coagents, that is, zinc dimethacrylate (ZDMA), N,N′‐m‐phenylene dimaleimide (HVA‐2), and trimethylolpropane trimethacrylate (TMPTMA) on a reinforcing substrate with dicumyl peroxide and hydrogenated acrylonitrile butadiene elastomer after processing was investigated with scanning electron microscopy. The morphology that evolved during processing was then compared to the results obtained from dynamic mechanical analysis (DMA) of the blends. Dynamic mechanical properties were modeled with a continuous relaxation distribution function, the Williams–Landel–Ferry equation, and the modified Guth–Gold equation. In the case of ZDMA and TMPTMA, a microphase and a nanophase evolved during processing, whereas the HVA‐2 phase in the blends remained well segregated. The volume fraction of the particles under 100 nm in ZDMA and TMPTMA blends ranged from 79 to 89%. The DMA results revealed the reinforcing effect of ZDMA and TMPTMA during the glass‐transition and in the plateau region, whereas HVA‐2 exhibited plasticizer‐like behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Experimental studies on the relaxation behavior of commercial polymer melts
Authors: Fan Yurun , Liao Huayong 
Published: July 2008

AbstractWith a rotary rheometer, various methods were used to determine the characteristic relaxation times for a commercial polydimethylsiloxane (PDMS), and their consistency and relation to the linear relaxation spectrum were examined. The experimental damping functions of the step deformation of the PDMS, a polymethylvinylsiloxane, and a high‐density polyethylene were compared with predictions of the Doi–Edwards theory and Marrucci model; the effect of wall slip on the damping function data is discussed, and the appearance of stress peaks due to material instability as the strain increased above a critical value is detailed. Through the application of a previously proposed stress decomposition method to the data of large‐amplitude oscillatory shear for the PDMS sample, the relationship between the generalized elastic modulus [G(ω,γ)] and the shear relaxation modulus [G(γ,t)] was investigated. In the linear and initial nonlinear regimes, as the angular frequency (ω) increased, G(ω,γ) approached G(γ,t) on the timescale t = 1/ω, where t is the time. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal profile of polypropylene and polyethylene. I. A novel look at a traditional technique
Authors: Elleithy Rabeh H. 
Published: July 2008

AbstractA new look at a traditional method of thermal characterization is offered. Oxidative induction temperature method is modified and revised to give a thermal profile of the polymer instead of a single‐point measurement. This article is an effort to not only describe a portion of the thermal behavior of polymers, but also to identify some thermal parameters. These parameters; thermal stability, strength, and stiffness, are proposed to be used like tensile properties to differentiate between the behavior of polymers under controlled conditions. The thermal parameters were successfully used to differentiate between two grades of polypropylene (PP), to study reprocessed PP, and to identify an injection molding problem for a client. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.
Thermal stability, crystallization behavior, and phase morphology of poly(ϵ‐caprolactone)diol‐grafted‐multiwalled carbon nanotubes
Authors: Jana R. N. , Cho Jae Whan 
Published: July 2008

AbstractPoly(ϵ‐caprolactone)diol (PCL) with five different molecular weights (e.g., 400, 2000, 3000, 4000, and 8000 g/mol) was grafted onto the surface of functionalized‐multiwalled carbon nanotubes (f‐MWNTs) by grafting to approach to form PCL‐grafted‐MWNTs (PCL‐g‐MWNTs). The grafting was confirmed by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). Thermal stability of PCL‐g‐MWNTs improved with the addition of f‐MWNTs in PCL, and the maximum was observed at 6 wt % of f‐MWNTs. Differential scanning calorimetric (DSC) studies showed that crystallization temperature, melting temperature, heat of crystallization, and heat of fusion decreased with the weight proportion of f‐MWNTs in the composites, but they showed an increasing trend with increasing molecular weight of PCL in the composites. DSC results were of good agreement with the X‐ray diffraction data, as crystallinity decreased with the incorporation of f‐MWNTs in PCL. The crystallite size (Phkl) of PCL in (110) direction increased, but in (200) direction it decreased. The size anisotropy (P110/P200) of the crystals in (110) and (200) directions increased regularly, indicating that the crystal growth was nonuniform in the two directions. The morphological observation by scanning electron microscopy and TEM showed that the PCL‐g‐MWNTs had higher diameter than raw multi‐walled carbon nanotubes. Polarized optical microscopy showed that PCL‐g‐MWNTs had core/shell structure with the nanotubes as the ‘hard’ core and the hairy polymer layer as the ‘soft’ shell. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Structure–property relationships in photopolymerizable polymer networks: Effect of composition on the crosslinked structure and resulting thermomechanical properties of a (meth)acrylate‐based system
Authors: Ortega Alicia M. , Kasprzak Scott E. , Yakacki Christopher M. , Diani Julie , Greenberg Alan R. , Gall Ken 
Published: July 2008

AbstractPhotoinitiated polymer networks were formed by copolymerization of tert‐butyl acrylate with di(ethylene glycol) dimethacrylate (DEGDMA) or poly(ethylene glycol) dimethacrylate (PEGDMA). The degree of crosslinking was systematically varied by modifying the weight fraction and molecular weight of the dimethacrylate crosslinking agent. An increase in effective crosslink density with increasing crosslinking agent concentrations was confirmed by decreasing equilibrium swelling ratios (q) and increasing rubbery moduli (ER). Glass transition temperatures (Tg) varied from −22 to 124°C, increasing with increasing DEGDMA content and decreasing with increasing PEGDMA content. Tensile deformation behavior (at Tg) ranged from an elastomeric‐like large‐strain response for lightly crosslinked materials to a small‐strain brittle response for highly crosslinked networks. At low crosslinking levels, the strain‐to‐failure of the network polymers decreased quickly with increasing crosslinking agent concentration. The stress at failure demonstrated a more complex relationship with crosslinking agent concentration. The effect of composition on network structure and resulting properties (q, ER, strain‐to‐failure) decreased as the crosslinking agent concentration increased. The results reveal trade‐offs in Tg, ER, strain‐to‐failure, and failure stress with composition and network structure, and are discussed in light of the wide range of potential applications suggested in the literature for (meth)acrylate‐based photopolymerizable polymer networks including biomaterials and shape‐memory polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Marked impact of P‐glycoprotein on the absorption of TAK‐427 in rats
Authors: Takeuchi Toshiyuki , Nonaka Masami , Yoshitomi Sumie , Higuchi Tomoaki , Ebihara Takuya , Maeshiba Yoshihiro , Kawase Masahiro , Asahi Satoru 
Published: July 2008

AbstractThe role of P‐glycoprotein (P‐gp, ABCB1) on the absorption process was investigated by drug–drug interaction studies of TAK‐427 with P‐gp inhibitors (erythromycin, ketoconazole or quinidine) in rats and by transport studies using rat multidrug resistance (MDR1) stably expressing cells and rat small intestine mounted in a Ussing‐type chamber. TAK‐427 showed high efflux activity with low permeability in rat MDR1a and MDR1b stably expressing cells and was revealed to be a typical substrate for P‐gps. Although TAK‐427 was mainly absorbed from the small intestine in rats, a large part of the dosed compound remained in the gastrointestinal tract. Orally co‐administered P‐gp inhibitors (50 mg/kg) increased theAUCof TAK‐427 after a 5 mg/kg oral dose 5.4‐ to 18.3‐fold, whereas orally administered P‐gp inhibitors had a minor effect on the increase in theAUCof TAK‐427 (1.3‐ to 2.2‐fold) after a 0.5 mg/kg intravenous dose. Thus, the bioavailability of TAK‐427 after oral administration in rats (7.3%) markedly increased when co‐administered with P‐gp inhibitors (28.6–57.6%). Moreover, the transport of TAK‐427 was predominantly secretory throughout the rat small intestine and was inhibited by P‐gp inhibitors. In conclusion, P‐gp can markedly reduce the absorption of a typical P‐gp substrate by its efflux activity throughout the absorption site. Copyright © 2008 John Wiley & Sons, Ltd.
Luminescence experiments involved in the mechanism of streptozotocin diabetes and cataract formation
Authors: Van Dyke Knox , Ghareeb Erica , Van Dyke Mark , Sosa Arturo , Hoeldtke Robert D. , Van Thiel David H. 
Published: July 2008

AbstractStreptozotocin (STZ)‐induced diabetes is linked to excessive nitric oxide (NO), and possibly peroxynitrite (OONO–) and/or other nitrogen oxides, e.g. nitrogen trioxide (N2O3), which damages DNA of pancreatic β cells, causing death and loss of insulin. Simultaneous injection of carboxy‐PTIO (CPTIO) and STZ prevents diabetes and cataract formation in rats, whereas 4‐hydroxy‐Tempo (4HT) does not. CPTIO oxidizes nitric oxide to nitrite, which prevents production of the diabetogenic toxin. Peroxynitrite may not be involved, since 4HT (converts O2– to H2O2) injected with STZ produces diabetes. All six of the control rats injected with STZ became diabetic and developed cataracts after 3 months. Eight rats injected with STZ and CPTIO were non‐diabetic with no cataracts up to a year. This work establishes the idea that excessive nitric oxide is a primary initiator in STZ diabetes. Luminescence experiments using OONO– generation from SIN‐1 with L‐012 indicates that 4HT is an effective inhibitor, while CPTIO is ineffective. Experiments with dilute solutions of nitrogen trioxide added to ladder or plasmid DNA reveal extensive nicking of DNA, thereby raising the possibility that other oxides of nitrogen could be involved with the damage to DNA. It can be concluded that diabetes can be prevented by oxidizing excessive NO from STZ. Copyright © 2008 John Wiley & Sons, Ltd.
Optimization of an enrichment process for circulating tumor cells from the blood of head and neck cancer patients through depletion of normal cells
Authors: Yang Liying , Lang James C. , Balasubramanian Priya , Jatana Kris R. , Schuller David , Agrawal Amit , Zborowski Maciej , Chalmers Jeffrey J. 
Published: July 2008

AbstractThe optimization of a purely negative depletion, enrichment process for circulating tumor cells (CTCs) in the peripheral blood of head and neck cancer patients is presented. The enrichment process uses a red cell lysis step followed by immunomagnetic labeling, and subsequent depletion, of CD45 positive cells. A number of relevant variables are quantified, or attempted to be quantified, which control the performance of the enrichment process. Six different immunomagnetic labeling combinations were evaluated as well as the significant difference in performance with respect to the blood source: buffy coats purchased from the Red Cross, fresh, peripheral blood from normal donors, and fresh peripheral blood from human cancer patients. After optimization, the process is able to reduce the number of normal blood cells in a cancer patient's blood from 4.05 × 109 to 8.04 × 103 cells/mL and still recover, on average, 2.32 CTC per mL of blood. For all of the cancer patient blood samples tested in which CTC were detected (20 out of 26 patients) the average recovery of CTCs was 21.7 per mL of blood, with a range of 282 to 0.53 CTC. Since the initial number of CTC in a patient's blood is unknown, and most probably varies from patient to patient, the recovery of the CTC is unknown. However, spiking studies of a cancer cell line into normal blood, and subsequent enrichment using the optimized protocol indicated an average recovery of approximately 83%. Unlike a majority of other published studies, this study focused on quantifying as many factors as possible to facilitate both the optimization of the process as well as provide information for current and future performance comparisons. The authors are not aware any other reported study which has achieved the performance reported here (a 5.66 log10) in a purely negative enrichment mode of operation. Such a mode of operation of an enrichment process provides significant flexibility in that it has no bias with respect to what attributes define a CTC; thereby allowing the researcher or clinician to use any maker they choose to define whether the final, enrich product contains CTCs or other cell type relevant to the specific question (i.e., does the CTC have predominately epithelial or mesenchymal characteristics?). Biotechnol. Bioeng. 2009;102: 521–534. © 2008 Wiley Periodicals, Inc.
Development of a rapid and sensitive liquid chromatography/tandem mass spectrometry method for the determination of 1,2‐[bis(1,2‐benzisoselenazolone‐3(2H)‐ketone)]‐ethane (BBSKE), a novel anti‐cancer agent in rat plasma
Authors: Zhou Hai‐Yan , Dou Gui‐Fang , Meng Zhi‐Yun , Lou Ya‐Qing , Zhang Guo‐Liang 
Published: July 2008

AbstractA rapid and sensitive liquid chromatography/electrospray ionization tandem mass spectrometric (LC/ESI‐MS/MS) method has been developed to determine 1, 2‐[bis(1,2‐benzisoselenazolone‐3(2H)‐ketone)]‐ethane (BBSKE), a novel antineoplastic agent, in rat plasma. The analytes were separated on a C18 column with a mobile phase of methanol–water (75:25, v/v) and detected using a triple‐quadrupole mass spectrometer in positive mode with the selective reaction monitoring. The characteristic ion dissociation transitions were m/z 603.0 → 448.9 for derivatized BBSKE and m/z 631.0 → 476.8 for derivatized internal standard. The assay was linear over a range of 1–1000 ng/mL with a lower limit of quantification of 1 ng/mL. Intra‐ and inter‐day precisions were less than 9.6 and 5.0%, respectively, and the accuracy ranged from −5.2 to 4.0%. The validated method was successfully applied to the characterization of pharmacokinetic profile of BBSKE after oral administration in rats. Copyright © 2008 John Wiley & Sons, Ltd.
Simultaneous determination of quinolone antibacterials in bovine milk by liquid chromatography–mass spectrometry
Authors: Zafra‐Gómez Alberto , Garballo Antonio , Ballesteros Oscar , Navalón Alberto , García‐Ayuso Luís E. 
Published: July 2008

AbstractA new liquid chromatography–mass spectrometry (LC–MS) method has been developed and validated for the simultaneous determination of eight quinolone antibacterials for veterinary use in processed bovine milk samples. The quinolones studied included marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine. Also, a new sample‐treatment procedure was used for extraction and preconcentration of these compounds. It involved defatting by centrifugation, protein precipitation by adding a mixture of glacial acetic acid–acetonitrile and removing acetonitrile with dichloromethane; finally, the acidified aqueous layer was evaporated to dryness in a speed vac system, resuspended in the mobile phase and filtered prior to LC injection. The mobile phase was composed of a formic acid aqueous solution 0.1% (v/v) and acetonitrile, with an initial composition of water–acetonitrile 95: 5 (v/v) and using linear gradient elution. Norfloxacin was used as internal standard. The limits of quantification found (2–7 ng g−1) were in all cases lower than the maximum residue limits tolerated by the European Union for these compounds in milk. Copyright © 2008 John Wiley & Sons, Ltd.
Determination and pharmacokinetic study of tussilagone in rat plasma by RP‐HPLC method
Authors: Liu Yu‐Feng , Yang Xiu‐Wei , Lu Wei , Xin Xiu‐Lan 
Published: July 2008

AbstractA simple and rapid high‐performance liquid chromatographic method was used to study the pharmacokinetics of tussilagone, one of the main bioactive constituents in the flower buds ofTussilago farfaraL. of traditional Chinese medicines, in rat plasma. Plasma was deproteinized by ethyl acetate for sample clean‐up. The drugs were separated on a Dikma Diamonsil™ C18column (4.6 × 250 mm, 5.0 µm), and detected by UV absorption at 220 nm. Methanol–water (75:25, v/v) was used as the mobile phase. It was applied to the pharmacokinetic study of tussilagone in rats after a dose of 5 mg/kg by intravenous administration and a dose of 200 mg/kg by intragastrical administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration–time curve by intravenous administration, while the plasma concentration–time curve of tussilagone conformed to a one‐compartment model by intragastrical administration. The absolute bioavailability of tussilagone is about 1.31%. Copyright © 2008 John Wiley & Sons, Ltd.
LC‐MS/MS method for the determination of cynandione A in rat plasma and tissues
Authors: Zhang Yaping , Shan Lei , Xu Wen , Yang Ming , Zhang Weidong , Li Haiyun 
Published: July 2008

AbstractA rapid and sensitive method using liquid chromatography–tandem mass spectroscopy (LC‐MS/MS) was developed and validated for the quantitative determination of cynandione A in rat plasma and tissues. The plasma samples were pretreated by liquid–liquid extraction with ethyl acetate after the internal standard (honokiol) had been spiked. The tissue samples were homogenized with physiological saline and treated further like the plasma samples. The separation was performed using a Zorbax SB‐C18 column (3.5 µm, 2.1 × 100 mm) and a C18 guard column (5 µm, 4.0 × 2.0 mm) with an isocratic mobile phase consisting of methanol–0.1% formic acid (78:22, v/v) at a flow rate of 0.2 mL/min. The Agilent G6410A triple quadrupole LC/MS system was operated under the multiple‐reaction monitoring mode using the electrospray ionization technique in negative mode. The nominal retention times for cynandione A and honokiol were 1.41 and 2.63 min, respectively. The method was validated within the concentration range 0.2–1000 ng/mL in plasma and homogenized tissue for cynandione A, and the calibration curves were linear with correlation coefficients >0.992. The lower limit of quantification of cynandione A was 0.2 ng/mL. The intra‐day and inter‐day precision and accuracy of the assay in plasma were less than 14.4%, while the intra‐day and inter‐day precision and accuracy of the assay in tissue homogenate were less than 14.2%. This method proved to be suitable for study of pharmacokinetics and tissue distribution of cynandione A in rat. Copyright © 2008 John Wiley & Sons, Ltd.