bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on preparation of PGMA/Al2O3 and its effect on impact strength of epoxy resin
Authors: Wang Ruixin , Gao Baojiao , Zhang Yan , Chen Limei 
Published: March 2009

AbstractIn this article, two kinds of methods for grafting polyglycidyl methacrylate (PGMA) onto Al2O3 surface by the radical polymerization initiated by peroxide groups and double bond groups, respectively, were investigated. In the first method, peroxide groups, as initiators, were immobilized onto the Al2O3 surface. Then, GMA was polymerized on Al2O3 under the radicals decomposed by peroxide groups, and PGMA was grafted onto Al2O3. But in the second method, 3‐methacryloylpropyl trimethoxysilane was chemically bonded onto the Al2O3 surfaces firstly to introduce double bonds. Secondly, the copolymerizations between the immobilized double bonds and the monomer GMA were performed, homopolymerizations of GMA followed, and finally PGMA was grafted to the Al2O3 surfaces. The effects of grafting methods on grafting degree were examined mainly. At the same time, the effects of different grafting conditions on the grafting degree were researched. Furthermore, the effect of the grafted particles PGMA/Al2O3 on impact strength of the epoxy composites was studied. It was found that the grafting degree achieved by the first method was much higher than that by the second, and the grafting degree can reach about 54%. Moreover, the impact strength of epoxy composites containing PGMA/Al2O3 particles were improved largely, and which increased with the grafting degree. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical relaxation of medical grade UHMWPE of different crosslink density as prepared by electron beam irradiation
Authors: Göschel Ulrich , Ulrich Christian 
Published: March 2009

AbstractDynamic mechanical thermal analysis (DMTA) has been applied on medical grade ultra high molecular weight polyethylene of different crosslink density as prepared by electron beam irradiation to probe for contributions from crosslinking as well as crystallization. The crosslinking proceeds at a crystalline structure with a crystallinity about 50%. With increasing irradiation dose from 0 to 110 kGy, the molar mass between adjacent crosslinks decreases significantly to reach 3170 g/mol at lowest, whereas the crystallite thickness changes and new thin lamellae grow at almost constant degree of crystallinity. From DMTA in the entire temperature range from −150 to +140°C and the angular frequency range from 0.6 to 135.4 Hz, three relaxation processes γ, β, and α of different temperature position and activation energy are distinguished. The corresponding chain mobility has been discussed as a sensitive discriminator for the coexisting crosslinked and lamellar phases showing the same dimension of a couple of 10 of nanometres. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The study on poly(ether sulfone) modified cyanate ester resin and epoxy resin cocuring blends
Authors: Zhan Guozhu , Hu Sheng , Yu Yingfeng , Li Shanjun , Tang Xiaolin 
Published: March 2009

AbstractPoly(ether sulfone) terminated with phenolic hydroxyl groups modified cyanate ester resin and epoxy resin cocuring blends were investigated by differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, rheometry, and mechanical properties measurement. The results suggested that poly (ether sulfone) (PES) could accelerate the polycyclotrimerization reaction of cyanate ester and cocuring processes between cyanate ester and epoxy of modified blends because of the presence of phenolic hydroxyl groups at the end of the PES molecules. It was found that the evolution of the morphologies and complex viscosities of the modified blends sensitive to molecular weight and content of PES, the tensile strength and elongation at break of the modified blends were correlated with the morphologies of modified blends. Moreover, the evolution of complex viscosities of the modified blends also showed an exponential growth at the early stage of phase separation, which demonstrated experimentally that the coarsening processes of droplets of bisphenol‐A dicyanate and diglycidyl ether of bisphenol A and the final morphologies obtained in the blends modified with PES were affected by viscoelastic behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of oxygen plasma treatment on interfacial properties of poly(p‐phenylene benzobisoxazole) fiber‐reinforced poly(phthalazinone ether sulfone ketone) composite
Authors: Zhang Chengshuang , Chen Ping , Sun Baolei , Lu Chun , Zhang Xiangyi , Liu Dong 
Published: March 2009

AbstractThe influence of oxygen plasma treatment on both surface properties of poly(p‐phenylene benzobisoxazole) (PBO) fibers and interfacial properties of PBO fiber reinforced poly(phthalazinone ether sulfone ketone) (PPESK) composite were investigated. Surface chemical composition, surface roughness, and surface morphologies of PBO fibers were analyzed by X‐ray photoelectron spectroscopy (XPS), Atomic force microscopy (AFM), and scanning electron microscopy (SEM), respectively. Surface free energy of the fibers was characterized by dynamic contact angle analysis (DCAA). The interlaminar shear strength (ILSS) and water absorption of PBO fiber‐reinforced PPESK composite were measured. Fracture mechanisms of the composite were examined by SEM. The results indicated that oxygen plasma treatment significantly improved the interfacial adhesion of PBO fiber‐reinforced PPESK composite by introducing some polar or oxygen‐containing groups to PBO fiber surfaces and by fiber surface roughening. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and electrochemical studies of layered PANI/HNb3O8 nanocomposite
Authors: Yang Gang , Liu Yuge , Hou Wenhua , Ji Hongmei , Li Yuhong 
Published: March 2009

AbstractAniline monomers could be easily inserted into and polymerized within the interlayers of HNb3O8. The conformation and electrochemical properties of the resulting nanocomoposites were discussed in detail. Two different mechanisms were proposed for the polymerization of monomers within the confined interlayers initiated by chemical oxidants and microwave irradiation, respectively. The analyses of thermogravimetric/differential scanning calorimetric analyses, X‐ray diffraction, and Fourier transform infrared spectra indicated that the aromatic rings of the interlayered polyaniline (PANI) could be parallel with or perpendicular to the inorganic slabs, and the interlayered PANI molecules were emeraldine salt and protonated by the protons of layered inorganic acid host. The cyclic voltammetry revealed that the properties of the layered host and the interlayer height have an effect on the redox behavior of the corresponding nanocomposites. Compared with the nanocomposites in which the aromatic rings were parallel with the inorganic slabs, the nanocomposites in which the aromatic rings were perpendicular to the slabs demonstrated a higher conductivity and electrochemical activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of silicone phosphate on the transesterification in PBT/PC blends
Authors: Lei Caihong , Chen Dahua , Gou Yuhui , Huang Weiliang 
Published: March 2009

AbstractBecause of the transesterification reaction between poly(butylene terephthalate) (PBT) and polycarbonate (PC), the crystallization behavior and thermal‐resistant properties of the blend have been known to be decreased. Therefore it is of importance to control the transesterification degree in PBT/PC blends. In this article, the effect of silicone phosphate on the transesterification reaction between PBT and PC was studied using differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and infrared spectroscopy (IR). It was found that the crystallization temperature of PBT/PC/silicone phosphate was 18.0°C higher than that of pure system, and the difference of the crystallization temperature between the first and secondary cooling cycles in DSC was 15.8°C lower than that of the pure system. IR results showed that both random and block copolymer existed in the stabilized system, and both IR and NMR results proved the decrease of the copolymer content by the introduction of silicone phosphate. Compared with that of the pure system, the Vicat soft temperature of the stabilized system was increased by 17.2°C. All the results showed that silicone phosphate was an effective inhibitor for the controlling of the transesterification reaction in PBT/PC blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Novel hydrogels based on itaconic acid and citraconic acid: Synthesis, metal ion binding, and swelling behavior
Authors: Jeria‐Orell Manuel , Pizarro Guadalupe del C. , Marambio Oscar G. , Geckeler Kurt E. 
Published: March 2009

AbstractSeveral copolymer hydrogels were prepared from radical copolymerization of 2‐hydroxypropyl methacrylate (HPMA) with itaconic acid (IA) and also with citraconic acid (CA) by using different feed ratios. The copolymers were characterized by FTIR, 1H‐NMR, and 13C‐NMR spectroscopy as well as by thermal analysis. The swelling process of the different hydrogels immersed in water at different pH has been studied, and also the swelling of the hydrogels loaded with metal ions (Pb2+, Cd2+) was investigated. The metal‐binding properties were studied by using the liquid‐phase polymer‐based retention technique, including studies on the influence of pH on the binding process. The efficiency of these hydrogels for the recovery of metal ions in solution was determined by atomic absorption spectroscopic analysis. The thermal characteristics of these copolymers were studied by using differential scanning calorimetry and thermogravimetric analysis in nitrogen atmosphere. Accordingly, the gels loaded with metal ions showed a slight increase of the thermal decomposition temperature when compared with the pristine gels. The copolymer gel HPMA‐co‐CA showed a single glass transition temperature, whereas for the copolymer systems, HPMA‐co‐IA, only the copolymers loaded with Cd2+ ions showed a glass transition temperature. The morphology of film produced from the copolymers was investigated by scanning electron microscopy, revealing generally smooth surfaces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Digestive proteolysis organization in two closely related Tenebrionid beetles: red flour beetle (Tribolium castaneum) and confused flour beetle (Tribolium confusum)
Authors: Vinokurov K.S. , Elpidina E.N. , Zhuzhikov D.P. , Oppert B. , Kodrik D. , Sehnal F. 
Published: March 2009

AbstractThe spectra of Tribolium castaneum and T. confusum larval digestive peptidases were characterized with respect to the spatial organization of protein digestion in the midgut. The pH of midgut contents in both species increased from 5.6–6.0 in the anterior to 7.0–7.5 in the posterior midgut. However, the pH optimum of the total proteolytic activity of the gut extract from either insect was pH 4.1. Approximately 80% of the total proteolytic activity was in the anterior and 20% in the posterior midgut of either insect when evaluated in buffers simulating the pH and reducing conditions characteristic for each midgut section. The general peptidase activity of gut extracts from either insect in pH 5.6 buffer was mostly due to cysteine peptidases. In the weakly alkaline conditions of the posterior midgut, the serine peptidase contribution was 31 and 41% in T. castaneum and T. confusum, respectively. A postelectrophoretic peptidase activity assay with gelatin also revealed the important contribution of cysteine peptidases in protein digestion in both Tribolium species. The use of a postelectrophoretic activity assay with p‐nitroanilide substrates and specific inhibitors revealed a set of cysteine and serine endopeptidases, 8 and 10 for T. castaneum, and 7 and 9 for T. confusum, respectively. Serine peptidases included trypsin‐, chymotrypsin‐, and elastase‐like enzymes, the latter being for the first time reported in Tenebrionid insects. These data support a complex system of protein digestion in the Tribolium midgut with the fundamental role of cysteine peptidases. © 2009 Wiley Periodicals, Inc.
Efficacy of repeat isolated limb infusion with melphalan and actinomycin D for recurrent melanoma
Authors: Kroon Hidde M. , Lin D‐Yin , Kam Peter C. A. , Thompson John F. 
Published: March 2009

AbstractBACKGROUND:Isolated limb infusion (ILI) is an effective and minimally invasive treatment option for delivering regional chemotherapy in patients with metastatic melanoma confined to a limb. Recurrent or progressive disease after an ILI, however, presents a challenge for further treatment. The value of repeat ILI in this situation has not been well documented.METHODS:Forty‐eight patients were identified who had been treated with a repeat ILI. In all patients, a cytotoxic combination of melphalan and actinomycin D was used.RESULTS:The median time between the 2 procedures was 11 months. The complete response (CR) rate after repeat ILI was 23%, compared with 31% after the initial ILI (P = .36). The overall response was 83%, compared with 75% after the first procedure (P = .32). The median duration of response was 11 months (10 months for patients with CR; P = .80), and median survival was 38 months. In those patients achieving a CR, the median survival was 68 months (P = .003). Toxicity after repeat ILI was increased, with 20 patients experiencing Wieberdink grade III limb toxicity (considerable erythema and edema with blistering) and 5 patients experiencing grade IV toxicity (threatened or actual compartment syndrome), whereas after the initial ILI these toxicity grades occurred in 14 patients and 1 patient, respectively (P = .03). No patient experienced grade V toxicity (requiring amputation).CONCLUSIONS:Repeat ILI is an attractive treatment option to achieve limb salvage in patients with inoperable recurrent or progressive melanoma after a previous ILI. It can be associated with significant short‐term regional toxicity, but is well tolerated by most patients, with satisfactory response rates. Cancer 2009. © 2009 American Cancer Society.
A novel hypothesis on the sensitivity of the fecal occult blood test
Authors: Lansdorp‐Vogelaar Iris , van Ballegooijen Marjolein , Boer Rob , Zauber Ann , Habbema J. Dik F. 
Published: March 2009

AbstractBACKGROUND:Estimates of the fecal occult blood test (FOBT) (Hemoccult II) sensitivity differed widely between screening trials and led to divergent conclusions on the effects of FOBT screening. We used microsimulation modeling to estimate a preclinical colorectal cancer (CRC) duration and sensitivity for unrehydrated FOBT from the data of 3 randomized controlled trials of Minnesota, Nottingham, and Funen. In addition to 2 usual hypotheses on the sensitivity of FOBT, we tested a novel hypothesis where sensitivity is linked to the stage of clinical diagnosis in the situation without screening.METHODS:We used the MISCAN‐Colon microsimulation model to estimate sensitivity and duration, accounting for differences between the trials in demography, background incidence, and trial design. We tested 3 hypotheses for FOBT sensitivity: sensitivity is the same for all preclinical CRC stages, sensitivity increases with each stage, and sensitivity is higher for the stage in which the cancer would have been diagnosed in the absence of screening than for earlier stages. Goodness‐of‐fit was evaluated by comparing expected and observed rates of screen‐detected and interval CRC.RESULTS:The hypothesis with a higher sensitivity in the stage of clinical diagnosis gave the best fit. Under this hypothesis, sensitivity of FOBT was 51% in the stage of clinical diagnosis and 19% in earlier stages. The average duration of preclinical CRC was estimated at 6.7 years.CONCLUSIONS:Our analysis corroborated a long duration of preclinical CRC, with FOBT most sensitive in the stage of clinical diagnosis. Cancer 2009. © 2009 American Cancer Society.
Patterns of treatment for early stage breast cancers at the M. D. Anderson Cancer Center from 1997 to 2004
Authors: Shen Yu , Dong Wenli , Feig Barry W. , Ravdin Peter , Theriault Richard L. , Giordano Sharon H. 
Published: March 2009

AbstractBACKGROUND:The objectives of this study were to examine the patterns of use for adjuvant therapy and the changes in surgical practice for patients with early stage breast cancer and to describe how recent large clinical trial results impacted the patterns of care at The University of Texas M. D. Anderson Cancer Center (MDACC).METHODS:The study included 5486 women who were diagnosed with stage I through IIIA breast cancer between 1997 and 2004 and received their treatment at MDACC. A chi‐square trend test and multivariate logistic regression model were used to assess changes in treatment patterns over time.RESULTS:Among lymph node‐positive patients, the use of anthracycline plus taxane chemotherapy increased from 17% in 1997 to 81% in 2004 (P < .001). Meanwhile, the use of anthracyclines without taxanes dropped from 76% to 20% (P < .001) between 1997 and 2000. For postmenopausal patients who received endocrine therapy, the use of tamoxifen was replaced increasingly by the use of aromatase inhibitors (from 100% on tamoxifen in 1997 to 14% in 2004; P < .001). The percentage of women who underwent initial sentinel lymph node biopsy increased significantly during the period from 1997 to 2004 (from 1.8% to 69.7%, respectively, among patients who underwent mastectomy; and from 18.1% to 87.1%, respectively, among patients who underwent breast‐conserving surgery; P < .001).CONCLUSIONS:The results from this study suggested that key findings from adjuvant therapy and surgical procedures from large clinical trials often prompt immediate changes in the patient care practices of research hospitals like MDACC. Cancer 2009. © 2009 American Cancer Society.
Evolution of Permanent Deformations (or Memory) in Nafion 117 Membranes with Changes in Temperature, Relative Humidity and Time, and Its Importance in the Development of Medium Temperature PEMFCs
Authors: Alberti G. , Narducci R. 
Published: March 2009

AbstractAn important problem for medium temperature polymer electrolyte fuel cells (MT PEMFCs) operating in the temperature range 90–140 °C is the short time‐life of proton conducting membranes. To shed some light on the empirical annealing treatments used for increasing the membrane durability, a systematic research on the effects of thermal treatments of Nafion 117 membranes was undertaken with the hope that the information obtained could be useful for a better understanding of the real limits for MT PEMFCs. Kinetic experiments showed that, for each couple of T–RH values, the water taken up from the membrane reaches a constant value only after long times of equilibration (≥200 h). Taking into account that the enlargements provoked by the water‐uptake remain as permanent deformations when the samples are cooled, it was found that the evolution of the deformations provoked by changes in temperature and RH can be conveniently estimated at 20 °C by determining the water taken up after equilibration in liquid water. By relating the counter‐elastic index of the matrix (nc(m)) to the extent of these deformations, a set of equations were obtained which allowed us to predict their evolution with changes of temperature and relative humidity. A good agreement with experimental values was found. The importance of this discovery for the development of MT PEMFCs is discussed.
Common and specific contributions of the intraparietal sulci to numerosity and length processing
Authors: Dormal Valérie , Pesenti Mauro 
Published: March 2009

AbstractNumerical and spatial magnitude processing have long been intimately associated, leading to the suggestion that they share a common system of magnitude representation. Although separate investigations on the cerebral areas involved in numerosity and spatial estimation point toward the parietal cortex, the precise anatomical overlap, if any, has not yet been directly established. Here, functional magnetic resonance imaging was used to localize the cerebral network involved in processing both numerosity and length. Blood oxygenation level‐dependent signal changes were measured while healthy volunteers were making numerosity comparisons on linear arrays of dots, and length comparisons on discrete linear arrays of dots and continuous rectangles. The results show the bilateral involvement of parietal regions around the intraparietal sulci in explicit and implicit processing of numerosity, and a right lateralized occipitoparietal network activation in length processing; numerosity and length processing both activate the right IPS and the precentral gyrus. By excluding the mandatory intrinsic spatial processing of arrays, we demonstrate that the left IPS is involved in numerosity processing only, whereas the right IPS underlies a common processing mechanism or representation of spatial and numerical magnitude. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.
Synthesis of the new adducts of imines and enamines with PH acids and their derivatives
Authors: Prishchenko Andrey A. , Livantsov Mikhail V. , Novikova Olga P. , Livantsova Ludmila I. , Milaeva Elena R. 
Published: March 2009

AbstractNucleophilic or radical addition of esters of trivalent organophosphorus acids with PH fragments to various imines and enamines is proposed as convenient methods for the synthesis of new substituted aminomethyl organophosphorus compounds with three‐, four‐, and five‐coordinated phosphorus. Also the new functionalized derivatives of these compounds with acyl and methanesulfonyl moieties are synthesized, and some properties of the obtained compounds are presented. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:70–80, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20513
Direct conversion of secondary phosphine oxides and H‐phosphinates with [Di(acyloxy)iodo]benzenes to phosphinic and phosphonic amides
Authors: Hubacz Anna , Makowiec Slawomir 
Published: March 2009

AbstractThe reaction of [di(acyloxy)iodo]benzene with secondary phosphine oxides or H‐phosphinates in the presence of primary or secondary amines allows one to obtain phosphinic or phosphonic acids amides in the one‐pot process. We take advantage of the strong acylating system DAIB/R2P(O)H to phosphinylation of amines. However, the reaction mechanism is multipathway and causes yields of phosphinic or phosphonic acids amides to be moderate. When the concentration of amines is low, the intermolecular process plays a main role leading to the formation of carboxylic amides through mixed phosphoric–carboxylic anhydride, and also in the low concentration of amines, tetrahydrofuran effectively competes with the amines in the nucleophilic attack on the acylating intermediates. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:81–86, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20514
Synthesis of novel aminophosphonic acids with hydantoin structure
Authors: Todorov Petar T. , Naydenova Emilia D. , Troev Kolio D. 
Published: March 2009

AbstractThe novel α‐aminophosphonic acids with hydantoin structure have been synthesized reacting 5,5‐dimetylhydantoin with formaldehyde and phosphorus trichloride, or via Kabachnik–Fields reaction. Their structures were proved by means of IR, 1H, 13C{1H}, and 31P NMR spectroscopy. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:87–90, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20515