bluuebunny/crossref_metadata_2025 huggingface dataset:
Photooxidation of Nanopatterned Poly(chloromethylstyrene): Direct Formation of Crosslinked Aldehyde‐Functionalized Films for Chemical Functionalization and Bioconjugation
Authors: Yu Xi , Subramani Chandramouleeswaran , Yang Xiaochao , Kim Chae Kyu , Rotello Vincent M.
Published: March 2010

UV irradiation of chloromethyl styrene simultaneously crosslinks the polymer and generates aldehyde groups that can be employed for polymer surface functionalization through aldehyde‐imine/hydrazone chemistry. Using this method, we successfully have functionalized nanoimprinted polymer patterns with dyes, nanoparticles, and enzymes. These surfaces were characterized by infrared (ATR‐IR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), fluorescence microscopy, and enzymatic activity assays.

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Single‐nucleotide polymorphisms in the p53 pathway genes modify cancer risk in BRCA1 and BRCA2 carriers of Jewish‐Ashkenazi descent
Authors: Yarden Ronit I. , Friedman Eitan , Metsuyanim Sally , Olender Tzvia , Ben‐Asher Edna , Papa Moshe Z.
Published: March 2010

Germline mutations in the BRCA1 and BRCA2 genes are associated with a significantly increased lifetime risk for developing breast and/or ovarian cancer. However, incomplete penetrance and substantial variability in age of disease onset among carriers of the same mutation suggests the involvement of additional modifier genes and/or environmental factors. Somatic inactivating mutations in the p53 gene and genes of the p53 pathway often accompany BRCA1/2‐associated tumors. Therefore, we assessed whether these genes are modifiers of penetrance. We genotyped Jewish‐Ashkenazi women for functional single‐nucleotide polymorphisms (SNPs) in the AKT1 (C>T rs3730358) and the PERP (C>T rs2484067) genes that affect p53‐mediated apoptosis, as well as two tag‐SNPs in the CHEK2 (C>T rs743184) and the ZBRK1/ZNF350 (G>A rs2278414) genes that encode for proteins involved in growth arrest following DNA damage. The study population included 138 healthy women, 148 breast/ovarian cancer BRCA1/2 mutation carriers, 121 asymptomatic BRCA1/2 mutation carriers, and 210 sporadic noncarrier breast cancer patients. Utilizing λ2 and Kaplan–Meier analysis revealed a hazard ratio (HR) of 3.23 (95% CI: 1.44–54, P = 0.0184) for the TT genotype of AKT (rs3730358), HR = 2.105 (95% CI: 1.049–7.434, P = 0.039) for CHEK2 CC genotype (rs743184), and HR = 2.4743 (95% CI: 1.205–11.53, P = 0.022) for the AG genotype of ZBRK1/ZNF350 (rs2278414). No significant association between PERP variants and cancer was identified HR = 0.662 (95% CI: 0.289–1.324, P = 0.261). Our results suggest that genes that act upstream of p53, or participate in the DNA damage response, may modify the risk of cancer in women with mutant BRCA1/2 alleles. © 2010 Wiley‐Liss, Inc.
Price setting and price adjustment in some European Union Countries: introduction to the special issue
Authors: Levy Daniel , Smets Frank
Published: March 2010

This introductory essay briefly summarizes the 11 empirical studies of price setting and price adjustment that are included in this special issue. The studies, which use data from several European countries, were conducted as part of the European Central Bank's Inflation Persistence Network. Copyright © 2010 John Wiley & Sons, Ltd.
Cross‐cultural evaluation of the modified Parkinson Psychosis Rating Scale across disease stages
Authors: Virués‐Ortega Javier , Rodríguez‐Blázquez Carmen , Micheli Federico , Carod‐Artal Francisco Javier , Serrano‐Dueñas Marcos , Martínez‐Martín Pablo
Published: March 2010

This study assessed the psychometric attributes of the modified Parkinson Psychosis Rating Scale (mPPRS). In an attempt to improve scale's scaling assumptions and content validity, all types of hallucinations were rated and all items were scored based on intensity. The scale was cross‐culturally adapted to four Latin American countries (Argentina, Brazil, Ecuador, and Paraguay). Acceptability, internal consistency, factor structure, convergent and known‐groups validity, and precision (standard error of measurement, SEM) were explored. A total of 388 patients with PD were included in the study (age, 64.5 ± 10.7 years; 59.8% males; PD duration, 8.2 ± 4.9 years). The mPPRS was highly usable in terms of missing values generated and scores distribution (total computable scores, 99.7%, ceiling effect, <15%). Scaling assumptions were acceptable as noted by the range of item‐total correlations (0.14–0.55, only one coefficient below 0.2). Internal consistency was adequate for research use (Cronbach alpha, 0.7). Factor analysis identified two factors that accounted for 58.5% of the variance. Low correlation coefficients were found with cognitive function (SCOPA‐Cog) and disease severity (CISI‐PD) (rS≤ 0.30), whereas correlation with psychosis were high (rS= 0.56). Known‐groups validity analyses indicated a significant increase in mPPRS scores by Hoehn and Yahr stage (P< 0.001). The SEM value was 1.06. Overall, the results suggest that the mPPRS is a useful tool for evaluation of psychosis in PD. The results show that some psychometric properties of the mPPRS are satisfactory albeit there is room for the improvement of scale's content validity and internal consistency. © 2010 Movement Disorder Society
Scrotal reconstruction with a free greater omental flap: A case report
Authors: Ng Darren , Tang Cheuk B. , Kadirkamanathan Sritharan S. , Tare Makarand
Published: March 2010

We report a case of Fournier's gangrene, where we used the greater omentum as a free flap for scrotal reconstruction and outline the advantages over previously described methods. The greater omentum was harvested using a standard open technique. The deep inferior epigastric vessels were passed through the inguinal canal into the scrotal area as recipient vessels. The detached greater omental flap was prefabricated into a three‐dimensional sac prior to inset and microvascular anastomoses. The flap was then covered by skin graft. The reconstruction had shown good early results with complete survival of the flap, as well as good functional and esthetic outcome at six months. The greater omentum can therefore be used as a free flap for scrotal reconstruction. It allows easy prefabrication and flap inset. The deep inferior epigastric vessels are also suitable recipient vessels. © 2010 Wiley‐Liss, Inc. Microsurgery 30:410–413, 2010.
Targeting murine small bowel and colon through selective superior mesenteric artery injection
Authors: Porvasnik Stacy L. , Mah Cathryn , Polyak Steven
Published: March 2010

Administration of molecular, pharmacologic, or cellular constructs to the intestinal epithelium is limited by luminal surface mucosal barriers and ineffective intestinal delivery via systemic injection. Many murine models of intestinal disease are used in laboratory investigation today and would benefit specific modulation of the intestinal epithelium. Our aim was to determine the feasibility of a modified microsurgical approach to inject the superior mesenteric artery (SMA) and access the intestinal epithelium. We report the detailed techniques for selective injection of the SMA in a mouse. Mice were injected with methylene blue dye to grossly assess vascular distribution, fluorescent microspheres to assess biodistribution and viral vector to determine biological applicability. The procedure yielded good recovery with minimal morbidity. Tissue analysis revealed good uptake in the small intestine and colon. Biodistribution analysis demonstrated some escape from the intestine with accumulation mainly in the liver. This microsurgical procedure provides an effective and efficient method for delivery of agents to the small intestine and colon, including biological agents. © 2010 Wiley‐Liss, Inc. Microsurgery 30:487–493, 2010.
Use of rat segmental intestine for fetal pancreatic transplantation
Authors: Iwasaki Junji , Hata Toshiyuki , Hishikawa Shuji , Fujimoto Yasuhiro , Uemoto Shinji , Murakami Takashi , Kobayashi Eiji
Published: March 2010

It is thought that the small intestine may provide a scaffold for pancreas regeneration. Herein, we investigated whether fetal pancreatic tissue could be transplanted into the segmental intestine in rats. Fetal pancreases from firefly luciferase transgenic Lewis rat embryos (embryonic day 14.5 and 15.5) were transplanted into streptozotocin (STZ)‐induced diabetic wild‐type Lewis rats. As a scaffold for pancreatic development, rat small intestinal segments were utilized after the removal of mucosa, and fetal pancreases were grafted into the luminal surface through the stoma. We also transplanted fetal pancreases into the omentum. The survival of transplanted fetal pancreases was monitored by luciferase‐derived photons and blood glucose levels. Transplanted fetal pancreas‐derived photons were stable for 28 days, suggesting that transplanted fetal pancreatic tissues survived and that their intestinal blood supply was maintained. © 2010 Wiley‐Liss, Inc. Microsurgery, 2010.
Compact dual‐wideband antenna for WLAN/WiMAX applications
Authors: Ye Liang‐Hua , Chu Qing‐Xin
Published: March 2010

A compact CPW‐fed dual‐wideband antenna formed by a rectangular ring monopole and a rectangular monopole is presented. The measured 10 dB bandwidths for return loss are achieved to be 46.3% (2.36–3.78 GHz) and 31.4% (5.1–7 GHz) in the lower and upper band, respectively, covering all the 2.4/5.2/5.8 GHz WLAN bands and the 2.5/3.5/5.5 GHz WiMAX bands. Further, the proposed antenna has a simple planar structure and occupies a small size of 28 × 36 mm2, including the finite ground CPW feeding mechanism. Good monopole‐like radiation characteristic are obtained over the operating bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1228–1231, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25156
Compact quad‐band antenna based on zeroth‐order resonator for mobile handset applications
Authors: Ji Jeong Keun , Kim Gi Ho , Seong Won Mo
Published: March 2010

A compact quad‐band antenna using zeroth‐order resonator (ZOR) for GSM850, DCS1800, PCS1900, and UMTS operations are presented. The proposed antenna comprises a lower band ZOR portion and an upper band ZOR portion. The zeroth‐order resonant properties are analyzed by amplitude and phase distributions of the surface magnetic field using near‐field scanning system. The performance of the antenna is verified by experimental data obtained from fabrication and measurement. The antenna offers omnidirectional radiation patterns and measured radiation efficiencies exceeding about 51% and 43% for lower and upper bands, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1298–1301, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25160
Ka‐band substrate integrated waveguide voltage‐controlled Gunn oscillator
Authors: Cao Zhou , Tang Xiaohong , Qian Kewei
Published: March 2010

A Ka‐band substrate integrated waveguide (SIW) voltage‐controlled oscillator (VCO) is demonstrated using GaAs Gunn diode.GaAs hyperabrupt varactor is employed in parallel to the Gunn diode for low phase noise and wideband tuning. The VCO achieves a tuning range of more than 1 GHz by varying the varactor tuning voltage between 0 V and 9 V, and phase noise of −102.1 dBc/Hz at 1 MHz offset from a 36 GHz carrier frequency. The output power varies from 9.3 dBm to 11.3 dBm within the tuning range. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1232–1235, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25169
Micromachined air‐filled patch antennas for millimeter‐wave applications
Authors: Wang Yi , Ke Maolong , Lancaster Michael J.
Published: March 2010

Air‐filled patch antennas for millimeter‐wave (mm‐wave) applications are demonstrated using silicon‐based micromachining techniques. The antennas are fed by rectangular coaxial lines and made of five gold plated layers bonded together. Each layer is made by deep reactive etching on silicon. The patches are suspended by stubs, without using any dielectric materials. The dielectric free structure not only avoids dielectric losses but also eliminates spurious surface modes that often trouble substrate supported patch antennas at mm‐wave frequencies. The predicted gain of the patch is as high as 9.4 dBi with a patch dimension of 3.27 mm by 3.54 mm at 38 GHz. A radiation pattern measurement has been performed and results shown. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1345–1347, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25183
Analysis of tunable flat dispersion of germanium doped fiber with liquid cladding
Authors: Liu Y. , Chen N. , Lai Y. , Chi S.
Published: March 2010

We demonstrate numerically the tunable dispersion‐flattened fibers can be achieved by immersing the Ge‐doped fiber core in different liquid claddings.The dispersion slope can be flattened over 1100–1700 nm, which is suitable for tunable supercontinuum generation with pumping wavelength in fiber communication or other wavelength regions. Finally, we demonstrate the feasibility to fabricate the proposed structure with chemical etching method. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1357–1359, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25209
Multi‐band chip antenna for WiMAX applications
Authors: Lin Shun‐Yun , Ke Bi‐Jin
Published: March 2010

A novel chip antenna for dual‐/tri‐band operation is presented in this article.The design consists of a pair of forked metal strips with different lengths. The longer strip is folded onto an FR4 base to simultaneously introduce the quarter‐ and half‐wavelength modes as the first two operating bands. By varying the included angle between the sections of strip on the opposite base layers, the frequency ratio of the first two operating modes is adjusted over a large range of 1.34–2.29. In addition, the shorter excited strip introduces the quarter‐wavelength mode as the third operating band. The tri‐band operation with a small dimension of 13 × 5 × 0.8 mm3for 2.5/3.5/5.5 GHz WiMAX applications is implemented. Experimental results show that the proposed antenna has good omnidirectional radiation patterns and steady antenna gains over all operating bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1286–1290, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25211
On the numerical resolution of the discontinuous material bifurcation problem
Authors: Oliver J. , Huespe A. E. , Cante J. C. , Díaz G.
Published: March 2010

The work focuses on the numerical resolution of the discontinuous material bifurcation problem as a relevant ingredient in computational material failure mechanics. The problem consists of finding the conditions for the strain localization onset in terms of the so‐called bifurcation time, localization directions and localization modes. A numerical algorithm, based on the iterative resolution of a coupled eigenvalue problem in terms of the localization tensor, is proposed for such purpose. The algorithm is shown to be always convergent to the exact solution for the symmetric case (major and minor symmetries of the tangent constitutive operator). In the unsymmetric case (only minor symmetries), the solution is no longer exact, although it is shown that using the symmetric part of the localization tensor in the proposed algorithms provides enough accurate solutions for most of cases. Numerical examples illustrate the benefits of the proposed methodology in terms of accuracy and savings in the computational cost associated with the problem. Copyright © 2010 John Wiley & Sons, Ltd.
Upfront use of gemtuzumab ozogamicin in young children with CD33‐positive AML
Authors: Sayar Dror , Burstein Yoav , Bielorai Bela , Toren Amos , Dvir Rina
Published: March 2010

Gemtuzumab ozogamicin (GO) is a humanized anti‐CD33 antibody used for treating patients with CD33+ acute myeloid leukemia (AML). We report three young children (two infants and one toddler) with AML treated with GO 9 mg/m2. Two received two doses at diagnosis alone with conventional chemotherapy and one received one dose after relapse. GO was well tolerated and all three achieved remission. All were transplanted: one relapsed after 5 months and died of disease, one died a toxic death in remission due to pulmonary fibrosis, and one survived (41 months from diagnosis). In conclusion, GO was well tolerated in these young patients with evidence for efficacy. Pediatr Blood Cancer 2010;55:183–185. © 2010 Wiley‐Liss, Inc.
A new methodology to preserve the original proportion and integrity of cell‐free fetal DNA in maternal plasma during sample processing and storage
Authors: Fernando M. R. , Chen K. , Norton S. , Krzyzanowski G. , Bourne D. , Hunsley B. , Ryan W. L. , Bassett C.
Published: March 2010

Objective

To develop a standardized blood collection device that preserves fetal cell‐free DNA and minimizes the cell‐free DNA background in maternal plasma.

Methods

Blood samples were drawn from healthy pregnant donors into K3EDTA (BD vacutainer®) and Cell‐free DNA™ BCT tubes (Streck®, Inc.) and kept at ambient temperature. Plasma was separated by centrifugation and cell‐free DNA was extracted. Cell‐free DNA from plasma was quantified by quantitative real‐time polymerase chain reaction.

Results

Blood drawn into Cell‐free DNA™ BCT tubes showed no change in the original proportion of fetal cell‐free DNA during a 14‐day storage period at ambient temperature. Conversely, maternal blood drawn into K3EDTA tubes showed a steady reduction in the original proportion of fetal cell‐free DNA over the same time period. Using maternal plasma stored in Cell‐free DNA™ BCT tubes for 14 days, fetal cell‐free DNA was amplified 80‐fold using whole genome amplification (WGA).

Conclusion

Using Streck's Cell‐free DNA™ BCT tubes, it is possible to preserve the original proportion of fetal cell‐free DNA for extended times as well as minimize the post‐sampling maternal cell‐free DNA background. Preserved in this way, fetal cell‐free DNA can be amplified by WGA technology to be used in prenatal diagnostic tests. Copyright © 2010 John Wiley & Sons, Ltd.
Orthogonal predictions: follow‐up questions for suggestive data
Authors: Walker Alexander M.
Published: March 2010

When a biological hypothesis of causal effect can be inferred, the hypothesis can sometimes be tested in the selfsame database that gave rise to the study data from which the hypothesis grew. Valid testing happens when the inferred biological hypothesis has scientific implications that predict new relations between observations already recorded. Testing for the existence of the new relations is a valid assessment of the biological hypothesis, so long as the newly predicted relations are not a logical correlate of the observations that stimulated the hypothesis in the first place. These predictions that lead to valid tests might be called ‘orthogonal’ predictions in the data, and stand in marked contrast to ‘scrawny’ hypotheses with no biological content, which predict simply that the same data relations will be seen in a new database. The Universal Data Warehouse will shortly render moot searches for new databases in which to test. Copyright © 2010 John Wiley & Sons, Ltd.
Validating injection stretch‐blow molding simulation through free blow trials
Authors: Menary G.H. , Tan C.W. , Armstrong C.G. , Salomeia Y. , Picard M. , Billon N. , Harkin‐Jones E.M.A.
Published: March 2010

A 2D isothermal finite element simulation of the injection stretch‐blow molding (ISBM) process for polyethylene terephthalate (PET) containers has been developed through the commercial finite element package ABAQUS/standard. In this work, the blowing air to inflate the PET preform was modeled through two different approaches: a direct pressure input (as measured in the blowing machine) and a constant mass flow rate input (based on a pressure–volume–time relationship). The results from these two approaches were validated against free blow and free stretch‐blow experiments, which were instrumented and monitored through high‐speed video. Results show that simulation using a constant mass flow rate approach gave a better prediction of volume vs. time curve and preform shape evolution when compared with the direct pressure approach and hence is more appropriate in modeling the preblowing stage in the injection stretch‐blow molding process. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Compatibilization of PP/PAE blends by means of the addition of an ionomer
Authors: Granado A. , Eguiazábal J.I. , Nazábal J.
Published: March 2010

Minor amounts of poly(ethylene‐co‐methacrylic acid) ionomer neutralized with Zn (PEMA‐Zn) were added in the melt state to blends of polypropylene (PP) with up to 40% of poly(amino ether) (PAE) resin. Given the good barrier characteristics of PAE, it is a good candidate to improve the poor barrier properties of PP. However, PP/PAE blends were found to be almost fully immiscible, with a large dispersed phase size and a brittle mechanical behavior. Upon PEMA‐Zn addition, the dispersed particle size clearly decreased from diameters of several microns to diameters mostly below 0.5 μm, indicating that compatibilization occurred. This compatibilization was due to the presence of PEMA‐Zn in the two phases of the blends and was additionally proven by the large decrease observed in the interfacial tension. Further, the fine morphology led to an enhancement in the unnotched impact strength of the ternary blends and of their ductile behavior (elongation at break 30‐ to 40‐fold that of the corresponding binary blends). POLYM. ENG. SCI., 50:1512–1519, 2010. © 2010 Society of Plastics Engineers
Pyrolysis of hyperbranched polyborate modified phenolic resin
Authors: Xu Peijun , Jing Xinli
Published: March 2010

Hyperbranched polyborate (HBPB) is a new polymer with highly branched structures, plenty of functional end groups and excellent thermal resistance, which can be used as a positive modifier for phenolic resin (PR) to greatly increase the carbon yield of PR. In the present article, thermal properties and structural changes of HBPB modified PR (PR‐HBPB) during the pyrolysis are studied. The pyrolysis mechanism of PR‐HBPB is proposed to explain the increase of the carbon yield of PR‐HBPB. It is found that the carbon yields of PR‐HBPBs containing 10 and 20 wt% of HBPB are 71.3 and 73.1% at 800°C in nitrogen, which are higher than those of PR and HBPB but not the sum of the carbon yields of PR and HBPB in consideration of their mixing ratio. The increase of carbon yield of PR‐HBPB can be attributed to the combined effects of the excellent thermal stability of HBPB, the formation of BC3 and B2O3, promoted graphitization by HBPB and the protection of B2O3 on the edges of the graphite microcrystallites. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Influence of molecular parameters on thermal, mechanical, and dynamic mechanical properties of hydrogenated nitrile rubber and its nanocomposites
Authors: Choudhury Anusuya , Bhowmick Anil K. , Ong Christopher , Soddemann Matthias
Published: March 2010

The present work derives a relationship between structure and properties of hydrogenated nitrile rubber (HNBR) in the presence as well as absence of nanofillers. Four different grades of HNBR were selected to examine the influence of polarity, unsaturation, and molecular weight on thermal, mechanical, and dynamic mechanical properties of the elastomers and particularly their nanocomposites. An increase in thermal stability, tensile strength, modulus at 100% elongation as well as storage modulus of the unfilled rubber was observed with increase in polarity (acrylonitrile content). Different nanofillers, such as montmorillonite, sepiolite, and nanosilica were used to improve the above properties of the unfilled rubber. Interestingly, a reverse trend of thermal properties was observed for the nanocomposites with acrylonitrile variation, although mechanical and dynamic mechanical properties exhibited similar trend to those of the unfilled rubber. These properties, however, gradually deteriorated as the level of unsaturation on the polymer backbone was increased. On addition of the nanofillers, it was found that the improvement in thermal and mechanical properties was higher for the elastomer having 5.5% diene content. The results were explained by X‐ray Diffraction, Atomic Force Microscopy, Energy Dispersive X‐ray mapping, and swelling studies. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Wear properties of 3‐aminopropyltriethoxysilane‐functionalized carbon nanotubes reinforced ultra high molecular weight polyethylene nanocomposites
Authors: Lee Ji‐Hoon , Kathi John , Rhee Kyong Yop , Lee Joong Hee
Published: March 2010

Ultra high molecular weight polyethylene (UHMWPE) is extensively used as a material in various high‐end applications with superior mechanical properties. Carbon nanotubes (CNTs) reinforced UHMWPE (CNT/UHMWPE) nanocomposite is a promising material that can compensate for the weak durability of UHMWPE. In this study, multiwalled carbon nanotubes were oxidized and silanized using acid mixture and 3‐aminopropyltriethoxysilane, respectively, to improve the interfacial strength between CNTs and UHMWPE. The CNT/UHMWPE nanocomposite was fabricated using these oxidized and silanized CNTs. The treatment effect of CNTs on the wear behavior of the CNT/UHMWPE nanocomposites was investigated through wear tests. The oxidization and silanization of CNTs were confirmed by infrared spectroscopy. Scanning electron microscope analysis showed that the silane‐treated CNT/UHMWPE nanocomposites showed better dispersion and interfacial adhesion between UHMWPE and CNTs becaue of the newly formed functional groups on the CNTs. The friction coefficient and wear rate of silanized CNT/UHMWPE nanocomposite were also found to be lower than those of raw UHMWPE and oxidized CNT/UHMWPE nanocomposite. CNTs were functionalized using oxidation and silanization methods to improve the interfacial adhesion between CNTs and UHMWPE. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Reinforcement of liquid ethylene–propylene–dicyclopentadiene copolymer based elastomer with vinyl functionalized multiwalled carbon nanotubes
Authors: Zhou Hongfu , Zhang Chen , Li Hangquan , Du Zhongjie , Li Congju
Published: March 2010

A methodology for reinforcement of liquid ethylene–propylene–dicyclopentadiene copolymer (liquid‐EPDM) based elastomer with multiwalled carbon nanotubes (MWCNTs) was proposed. Acid‐treated MWCNTs were first reacted with poly(acryloyl chloride) (PACl) leading to a grafted encapsulation, which were subsequently reacted with hydroxy ethyl acrylate (HEA) to generate vinyl groups. Thus obtained vinyl groups functionalized MWCNTs (vinyl‐MWCNTs) were characterized using Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. The vinyl‐MWCNTs were blended with liquid‐EPDM and subjected to co‐curing; an intercrosslinked structure was obtained via the free radical polymerization among the vinyl groups on vinyl‐MWCNTs and the double bonds on liquid‐EPDM. As a result, the vinyl‐MWCNTs and the cured EPDM matrix were covalently linked. The chemical interfacial interaction between vinyl‐MWCNTs and the cured matrix were observed by scanning electron microscope, which provided obvious reinforcement of elastomer. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Three‐dimensional scanning electron microscopy characterization of the topography of textured polymeric surfaces
Authors: Ignell Sofie , Ariño Ruth , Iannuzzi Giovanna , Kleist Ulf , Rigdahl Mikael
Published: March 2010

A stereographic scanning electron microscopy (SEM) technique combined with a filtering procedure was used to characterize the surface topography of injection‐molded polymeric plaques to improve the understanding of the relation between surface texture and gloss of deliberately textured and quite rough surfaces. The specimens, having small differences in surface topography and gloss, were produced by using two mold cavities with slight differences in surface texture and three different polymers. Small differences in gloss were also achieved by changing the processing conditions. All specimens exhibited a very low gloss. A stereographic image of the textured surface was constructed from two SEM micrographs of the same area, but differing slightly in viewing angle. From this image, descriptors characterizing the surface topography could be evaluated, in the present study the root‐mean‐square roughness and a lateral correlation length. The results indicated that small differences in gloss in the low gloss region could to a significant extent be associated with small‐scale variations in the surface topography. The SEM method used might provide a useful tool for identifying the length scale at which the surface pattern or irregularities has a strong effect on the appearance of polymeric low‐gloss surfaces. POLYM. ENG. SCI., 50:1527–1534, 2010. © 2010 Society of Plastics Engineers
Chain internal/chain end latent crosslinking in thermoset polymer systems
Authors: Matloka Piotr P. , Kean Zachary , Wagener Kenneth B.
Published: March 2010

The combination of both chain‐internal/chain‐end latent crosslinking in a single thermoset polymer system is the subject of this study. A series of linear carbosiloxane/hydrocarbon homopolymers were synthesized by metathesis polycondensation, polymers which serve as the soft phase in the target chain‐internal/chain‐end latent crosslinked materials. These carbosiloxane/hydrocarbon “soft phase” homopolymers exhibited excellent performance parameters, displaying purely amorphous character with glass transition temperatures ranging between −104 °C and −90 °C depending on the run length of siloxane or hydrocarbon methylene units within the carbosiloxane/hydrocarbon monomer. These soft phase monomers were then copolymerized with latent chain‐internal crosslinking carbosilane monomers in the presence of latent chain‐end crosslinking molecules thereby generating a new class linear copolymers capable of being moisture cured to produce a new class of silicon‐based thermoset systems. Mechanical properties of these thermosets, show breaking strengths up to 0.5 MPa and elongations up to 100%. Both elastic and plastic behavior can be observed in such systems, depending upon the molar ratio of carbosiloxane/hydrocarbon co‐monomer and the carbosilane co‐monomer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1866–1877, 2010
End‐linked amphiphilic polymer conetworks: Synthesis by sequential atom transfer radical polymerization and swelling characterization
Authors: Rikkou Maria D. , Kolokasi Maria , Matyjaszewski Krzysztof , Patrickios Costas S.
Published: March 2010

Conetworks based on end‐linked homopolymers and amphiphilic gradient copolymers were synthesized by the atom transfer radical polymerization (ATRP) of 2‐(dimethylamino)ethyl methacrylate (DMAEMA, hydrophilic monomer), methyl methacrylate (MMA, hydrophobic monomer), and ethylene glycol dimethacrylate (EGDMA, hydrophobic cross‐linker). Sequential, rather than step‐wise polymerizations, were performed to enhance the livingness of the polymerization, particularly for the end‐linking step, and to ultimately obtain conetworks based on gradient rather than pure block copolymers. Amphiphilic conetworks based on end‐linked MMA‐DMAEMA‐MMA gradient copolymers of different compositions were successfully synthesized as confirmed by the narrow molecular weight distributions of the linear precursors, the rigidity of the amphiphilic conetwork products and the low sol‐fraction extracted from the conetworks. Similarly successful was the ATRP synthesis of an end‐linked conetwork based on a DMAEMA‐MMA statistical copolymer and of a randomly cross‐linked conetwork that resulted from the simultaneous terpolymerization of DMAEMA, MMA and EGDMA. An amphiphilic conetwork based on an end‐linked DMAEMA‐MMA‐DMAEMA gradient copolymer presented a less rigid, mucous‐like, texture. The degrees of swelling (DS) in tetrahydrofuran of all the conetworks were higher than those measured in pure water, whereas the aqueous DS values increased by lowering the pH and increasing the DMAEMA content of the conetworks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1878–1886, 2010
Facile one‐pot synthesis and thermal cyclopolymerization of aryl bistrifluorovinyl ether monomers bearing reactive pendant groups
Authors: Zhu Kaizheng , Iacono Scott T. , Budy Stephen M. , Jin Jianyong , Smith Dennis W.
Published: March 2010

A diverse pool of aryl bistrifluorovinyl ether (BTFVE) compounds with reactive pendant groups were prepared in a facile, high yielding three step “one‐pot” synthesis from commercial 4‐bromo(trifluorovinyloxy)benzene. Monomers were confirmed from ATR–FTIR, 1H, 13C, and 19F NMR, and HRMS analysis. Aryl BTFVE compounds were thermally polymerized to afford perfluorocyclobutyl (PFCB) aryl ether polymers with high number–average molecular weight (Mn) for homopolymers (17,050–27,090) and copolymers with 4,4′‐bis(trifluorovinyloxy)biphenyl monomers (27,860–56,500). The PFCB aryl ether homo‐ and copolymers collectively possess high thermal stability (>299 °C in N2) and are readily solution processable producing optically transparent films. The thermal polymerization was achieved and reactive moieties remained intact, aside from those functionalized with acrylates. In the case with acrylate functionalized polymers, orthogonal polymerization was achieved by first photopolymerizing the acrylates followed by thermal curing of the aryl trifluorovinyl ether endgroups. Preliminary results in this study produced the successful preparation of photodefinable PFCB aryl ether material. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1887–1893, 2010
Organic soluble deoxyribonucleic acid (DNA) bearing carbazole moieties and its blend with phosphorescent Ir(III) complexes
Authors: Cho Min Ju , Lee U Ra , Kim Youn Sun , Shin Jicheol , Kim Young Min , Park Young Wook , Ju Byeong‐Kwon , Jin Jung‐Il , Choi Dong Hoon
Published: March 2010

A functionalized deoxyribonucleic acid (Cz‐DNA) was prepared with carbazolyl ammonium lipid as a triplet host material for phosphorescent material system. It is soluble in organic solvents, which facilitates the sample preparation for the absorption and luminescent properties in solid states. A highly soluble iridium complex, Ir(Cz‐ppy)3 with carbazolyl‐substituted 2‐phenylpyridine ligands was employed for studying the phosphorescence in Cz‐DNA. There is a good overlap between the photoluminescence spectrum of Cz‐DNA and the metal‐to‐ligand charge transfer (MLCT) absorption bands of the iridium complex. This overlap enables efficient energy transfer from the excited state in the host to the MLCT band of Ir(Cz‐ppy)3. In addition, photoluminescence quantum yield of Cz‐DNA was found to be relatively larger than the copolymer (PCzSt) with vinylcarbazole and styrene. Thus, Cz‐DNA was employed as a triplet host material for fabricating multilayered electrophosphorescence devices via modification of its property by doping 5,4‐tert‐butylhexyl‐1,3,4‐oxadiazole (PBD). After doping 30 wt % PBD and 10 wt % Ir(Cz‐ppy)3 into Cz‐DNA, we achieved much improvement in electron injection/transport from an adjacent carrier transport layer, resulting in much improved device performances. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1913–1918, 2010
Synthesis and physicochemical characterization of biodegradable and pH‐responsive hydrogels based on polyphosphoester for protein delivery
Authors: He Jinlin , Ni Peihong , Wang Sai , Shao Haiyan , Zhang Mingzu , Zhu Xiulin
Published: March 2010

In this work, a series of biodegradable and pH‐responsive hydrogels based on polyphosphoester and poly(acrylic acid) are presented. A novel biodegradable macrocrosslinker α‐methacryloyloxyethyl ω‐acryloyl poly(ethyl ethylene phosphate) (HEMA‐PEOP‐Ac) was synthesized by first ring‐opening polymerization of the cyclic monomer 2‐ethoxy‐2‐oxo‐1,3,2‐dioxaphospholane using HEMA as the initiator and Sn(Oct)2 as catalyst, and subsequent conversion of hydroxyl into vinyl group. The hydrogels were then fabricated by the copolymerization of the macromonomer with acrylic acid, and their swelling/deswelling and degradation behaviors were investigated. The results demonstrated that the crosslinking density and pH values of media strongly influenced both the swelling ratio and the degradation rate of the hydrogels. The rheological properties of these hydrogels were also studied from which the storage modulus (G′) showed clear dependence on the crosslinking density. MTT and “live/dead” assay showed that these hydrogels were compatible to fibroblast cells, not exhibiting apparent cytotoxicity even at high concentrations. Moreover, in vitro bovine serum albumin release from these hydrogels was also investigated, and it could be found that the release profiles showed a burst effect followed by a continuous release phase, and the release rate was inversely proportional to the crosslinking density of hydrogels. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1919–1930, 2010
Tough interconnected polymerized medium and high internal phase emulsions reinforced by silica particles
Authors: Wu Ranting , Menner Angelika , Bismarck Alexander
Published: March 2010

Emulsion templating using high internal phase emulsions is an effective route to prepare low density and high porosity macroporous polymers known as polymerized high internal phase emulsions (polyHIPEs). Conventional polyHIPEs, synthesized from surfactant stabilized w/o emulsions have low permeabilities and poor mechanical properties. We present interconnected open macroporous low density nanocomposites produced by polymerizing the continuous phase of emulsion templates, which contained styrene, polyethyleneglycoldimethacrylate, and silylated silica particles. Polyethyleneglycoldimethacrylate and the silylated silica particles acted as crosslinker. The functionalized silica particles were incorporated into the polymer, which resulted in a significant improvement of the mechanical properties of the polyHIPEs without affecting the interconnected and permeable pore structures. The polyHIPEs contained up to 60 wt % silylated silica particles. Young's modulus of the reinforced macroporous polymers increased up to 600% compared with nonreinforced macroporous polymers. The mechanical performance was further increased by increasing the foam density of the macroporous nanocomposites from around 200 to 370 g/cm3 by raising the organic phase volume of the emulsion templates from 20 to 40 vol %. The macroporous polymers synthesized from less concentrated emulsions also possessed interconnected open porous although less permeable structures. The polyHIPE nanocomposites have a permeability of about 200 mD, whereas the polyMIPE nanocomposites still have permeabilities of around 50 mD. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1979–1989, 2010
Air‐tolerantly surface‐initiated AGET ATRP mediated by iron catalyst from silica nanoparticles
Authors: Li Qiang , Zhang Lifen , Zhang Zhengbiao , Zhou Nianchen , Cheng Zhenping , Zhu Xiulin
Published: March 2010

Well‐defined polymer‐nanoparticle hybrids were prepared by a newly reported method: atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) mediated by iron catalyst. The kinetics of the surface‐initiated AGET ATRP of methyl methacrylate from the silica nanoparticles, which was mediated by FeCl3/triphenylphosphine as a catalyst complex, ascorbic acid as a reducing agent, N,N‐dimethylformamide as the solvent in the presence of a “sacrificial” (free) initiator, was studied. Both the free and grafted polymers were grown in a control manner. The chemical composition of the nanocomposites was characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Thermogravimetric analysis was used to estimate the content of the grafted organic compound, and transmission electron micrographs was used to observe the core‐shell structure of the hybrid nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2006–2015, 2010
Synthesis of polystyrene‐based random copolymers with balanced number of basic or acidic functional groups
Authors: Dimitrov Ivaylo , Jankova Katja , Hvilsted Søren
Published: March 2010

Pairs of polystyrene‐based random copolymers with balanced number of pendant basic or acidic groups were synthesized utilizing the template strategy. The same poly[(4‐hydroxystyrene)‐ran‐styrene] was used as a template backbone for modification. Two different synthetic approaches for the functionalization were applied. The first one involved direct functionalization of the template backbone through alkylation of the phenolic groups with suitable reagents. The second modification approach was based on “click” chemistry, where the introduction of alkyne groups onto the template backbone was followed by copper‐catalyzed 1,3 cycloaddition of aliphatic sulfonate‐ or amine‐contaning azides. Both synthetic approaches proved to be highly efficient as evidenced by 1H‐NMR analyses. The thermal properties were evaluated by differential scanning calorimetry and thermal gravimetric analyses and were influenced by the type of functionality and the modification method. The ether‐linked functional colopymers were thermally more stable than their “clicked” analogues. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2044–2052, 2010
Crystal growth rates and master curves of poly(ethylene succinate) and its copolyesters using a nonisothermal method
Authors: Tsai Chia‐Jung , Chen Ming , Lu Hsin‐Ying , Chang Wei‐Che , Chen Chi He
Published: March 2010

The spherulitic growth of poly(ethylene succinate) (PES) and two PES‐rich copolyesters at constant cooling rate was monitored and recorded using a system of polarized light microscope. Individual experiment of these polyesters lasted 40, 60, and 120 min, respectively. A continuous curve of isothermal growth rates between the melting and glass transition temperatures can be obtained after curve fitting procedures. These curves fit very well with those data points determined in the isothermal experiments, which are time consuming. The continuous data of PES was analyzed with the Hoffman (Lauritzen equation. A transition of regime II → III was found at 70.7 °C, which is very close to the literature values. The maximum growth rate was formulated in the Arrhenius and WLF expressions for the molecular transport term. A master curve of crystal growth rate for PES was constructed based on the continuous data of PES. When the reduced growth rates after normalization were plotted against the reduced temperatures, a universal master curve was observed for PES and two PES‐rich copolyesters. This nonisothermal method provides an efficient and reliable way for studying the crystallization kinetics of polymer and for constructing a universal master curve of crystal growth rate of PES. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 932–939, 2010
Biological Evaluation of DNA Damage in Bacteriophages Inactivated by Atmospheric Pressure Cold Plasma
Authors: Yasuda Hachiro , Miura Takuya , Kurita Hirofumi , Takashima Kazunori , Mizuno Akira
Published: March 2010

Inactivation mechanisms of plasma treated microorganisms are still major subjects. We have developed a biological assay which evaluates in vivo DNA damage of the viruses treated with non‐thermal atmospheric pressure plasma in air. Different doses of the plasma were applied to wet state of λ phage particles under neutral pH and near the room temperature. From each sample of treated λ phages, DNA was purified and subjected to in vitro DNA packaging reactions. Survival curves of the re‐packaged phages showed an extremely large D value (D = 25 s) compared to the previous D value (D = 3 s) obtained from the survival curves of the treated phages. The results indicate the evidence that DNA damage hardly contributed to the inactivation.

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Crystal structure of the C‐terminal domain of the Salmonella type III secretion system export apparatus protein InvA
Authors: Worrall Liam J. , Vuckovic Marija , Strynadka Natalie C. J.
Published: March 2010

InvA is a prominent inner‐membrane component of the Salmonella type III secretion system (T3SS) apparatus, which is responsible for regulating virulence protein export in pathogenic bacteria. InvA is made up of an N‐terminal integral membrane domain and a C‐terminal cytoplasmic domain that is proposed to form part of a docking platform for the soluble export apparatus proteins notably the T3SS ATPase InvC. Here, we report the novel crystal structure of the C‐terminal domain of Salmonella InvA which shows a compact structure composed of four subdomains. The overall structure is unique although the first and second subdomains exhibit structural similarity to the peripheral stalk of the A/V‐type ATPase and a ring building motif found in other T3SS proteins respectively.
Finiteness in SU(3)3 models
Authors: Heinemeyer S. , Ma E. , Mondragon M. , Zoupanos G.
Published: March 2010

We consider N = 1 supersymmetric gauge theories based on the group SU(N)1 × SU(N)2 × … × SU(N)k with matter content (N, N*, 1, …, 1) + (1, N, N*, …, 1) + … + (N*, 1, 1, …, N), which are finite if and only if there are exactly three generations. We study in particular two models with SU(3)3 as gauge group, an all‐loop and a two‐loop finite model, and we examine their predictions concerning the third generation quark masses.
Monitoring for imidacloprid resistance in the tobacco‐adapted form of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), in the eastern United States
Authors: Srigiriraju Lakshmipathi , Semtner Paul J , Bloomquist Jeffrey R
Published: March 2010

BACKGROUND: Imidacloprid is the primary insecticide for controlling the tobacco‐adapted form of the green peach aphid (TGPA), Myzus persicae (Sulzer), a major pest of tobacco worldwide. This study used leaf‐dip bioassays to assess TGPA resistance to imidacloprid in the eastern United States from 2004 through 2007.

RESULTS: When combined over the 4 year study, 18, 14 and 3% of the TGPA had imidacloprid resistance ratios (RRs) of 10–20‐fold, 20–30‐fold and 30–90‐fold, respectively, compared with the most susceptible colony tested. This indicates that some colonies have developed moderate levels of resistance to imidacloprid. A colony collected near Clayton, North Carolina, had the highest RR of 91 (LC50 value = 31 mg L−1). This resistance declined for six tests over a 3 year period in the laboratory culture from >130‐fold RR (LC50 = 48 mg L−1) to 40‐fold RR (LC50 = 15 mg L−1). Over the same period, the most susceptible colony and a standard colony not exposed to imidacloprid for over 7 years had consistently low LC50 values.

CONCLUSION: Moderate levels of resistance to imidacloprid are noticed among TGPA colonies from the eastern United States. The variation in resistance indicates that the factors responsible are present in the populations at low frequencies and are just not enough to cause field failures yet. Copyright © 2010 Society of Chemical Industry