bluuebunny/crossref_metadata_2025 huggingface dataset:
Routine Microsurgical Biliary Reconstruction Decreases Early Anastomotic Complications in Living Donor Liver Transplantation
Authors: Lin Tsan-Shiun , Concejero Allan M. , Chen Chao-Long , Chiang Yuan-Cheng , Wang Chih-Chi , Wang Shih-Ho , Liu Yueh-Wei , Yang Chin-Hsiang , Yong Chee-Chien , Jawan Bruno , Cheng Yu-Fan
Published: November 2009

Biliary reconstruction using a microsurgical technique in living donor liver transplantation was routinely performed on 88 grafts primarily transplanted into 85 patients. All procedures were performed under a microscope by a single microsurgeon. Except for biliary atresia and Alagille syndrome, duct-to-duct reconstruction was performed. Stents were not used. The outcomes with microsurgical biliary reconstruction (MB) were compared with the outcomes of a cohort of 86 grafts in 85 patients that underwent conventional biliary reconstruction (CB). The identification of complications included only up to 12 months of follow-up for each recipient in both groups. The average graft duct sizes were 2.8 mm for MB and 3.4 mm for CB. Most complications occurred in the first 15 cases with MB, and these cases were considered to constitute the learning curve phase. The MB complication rate was 46.7% in the first 15 cases, 20.0% in the next 15 cases, and 5.4% in the last 55 cases. When the learning curve phase was excluded, the overall complication rate over time with MB (8.9%) was significantly lower than that with CB (21.9%). CB increased the risk of biliary complications by 2.5 times (relative risk: 2.5; attributable risk: 128; odds ratio: 2.9). In conclusion, routine MB is a technical innovation that leads to decreased early anastomotic complications in living donor liver transplantation. Liver Transpl 15:1766-1775, 2009. © 2009 AASLD.
Mathematical Modeling and Optimization of Run Parameters of Crystallization Analysis Fractionation (CRYSTAF)
Authors: Fischlschweiger Michael , Aust Nicolai , Oberaigner Eduard R. , Kock Cornelia
Published: November 2009

Blends of a random poly(propylene) copolymer with different types of polyethylene were used to develop a sample independent statistic mathematical model which describes the quality of phase separation of polymer blends obtained by CRYSTAF. By coupling the abstract model with experimental data, process parameters influencing the non‐equilibrium CRYSTAF separation process can be determined. It could be shown that the stirring speed applied during the fractionation process strongly influences the resolution of the derived CRYSTAF profile and thus the quality of fractionation. Nonlinear optimization of the models' response function leads to optimized run parameters for the CRYSTAF process which results in CRYSTAF profiles of high resolution and thus to a high quality in fractionation.

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A Novel High Throughput Method to Investigate Polymer Dissolution
Authors: Zhang Ying , Mallapragada Surya K. , Narasimhan Balaji
Published: November 2009

The dissolution behavior of polystyrene (PS) in biodiesel was studied by developing a novel high throughput approach based on Fourier‐transform infrared (FTIR) microscopy. A multiwell device for high throughput dissolution testing was fabricated using a photolithographic rapid prototyping method. The dissolution of PS films in each well was tracked by following the characteristic IR band of PS and the effect of PS molecular weight and temperature on the dissolution rate was simultaneously investigated. The results were validated with conventional gravimetric methods. The high throughput method can be extended to evaluate the dissolution profiles of a large number of samples, or to simultaneously investigate the effect of variables such as polydispersity, crystallinity, and mixed solvents.

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New Low Bandgap Dithienylbenzothiadiazole Vinylene Based Copolymers: Synthesis and Photovoltaic Properties
Authors: Liu Bo , Najari Ahmed , Pan Chunyue , Leclerc Mario , Xiao Dequan , Zou Yingping
Published: November 2009

Two new low‐bandgap block copolymers derived from dithienylbenzothiadiazole (DTBT) and different electron‐rich functional groups (dioctoxyl benzene and N‐octyl‐diphenylamine), poly(1,4‐dioctoxyl‐2,5‐divinylbenzene‐co‐4,7‐dithiophene‐2′‐yl‐2,1,3‐benzothiadiazole) (PPV‐DTBT), poly(3,8‐divinyl‐N‐octyl‐diphenylamine‐co‐4,7‐dithiophene‐2′‐yl‐2,1,3‐benzothiadiazole) (PDPAV‐DTBT), were synthesized by Heck cross‐coupling polymerization. PPV‐DTBT and PDPAV‐DTBT are easily soluble in common organic solvents such as o‐dichlorobenzene and chloroform. DSC and TGA results indicate that these copolymers possess good thermal stabilities. PPV‐DTBT and PDPAV‐DTBT films exhibit broad absorption bands at 300–765 nm (with an optical bandgap of 1.62 eV) and 300–733 nm (with an optical bandgap of 1.69 eV), respectively. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of PPV‐DTBT were estimated by cyclic voltammetry to be −5.43 and −3.74 eV, respectively, and the HOMO and LUMO of PDPAV‐DTBT were −5.37 and −3.7 eV, respectively. Preliminary photovoltaic cells based on the composite structure of ITO/PEDOT: PSS/PPV‐DTBT:PCBM (1: 2, w/w)/Al showed an open‐circuit voltage of 0.75 V, a power conversion efficiency of 0.6%, and a short circuit current of 1.7 mA · cm−2.

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Physicochemical properties and thermal stability of Lep w 1, the major allergen of whiff
Authors: Griesmeier Ulrike , Bublin Merima , Radauer Christian , Vázquez‐Cortés Sonia , Ma Yan , Fernández‐Rivas Montserrat , Breiteneder Heimo
Published: November 2009

Whiff (Lepidorhombus whiffiagonis) is a fish frequently consumed in Spain. Lep w 1, its major allergen, is a calcium‐binding β‐parvalbumin. The resistance of Lep w 1 to heat denaturation and to digestion were studied by circular dichroism spectroscopy and by in vitro gastric digestion systems. Purified Lep w 1 was thermally stable up to 65°C at neutral pH. Calcium depletion resulted in a change of its structure as determined by circular dichroism spectroscopy. A partial loss of structure was also observed at acidic pH; however, the allergen retained its full IgE‐binding ability. The partially denatured Lep w 1 was easily digested by pepsin within 2 min. Further, the IgE reactivity of proteins extracted from cooked fish and their stability to proteolysis were analyzed. The extract revealed a higher number of IgE reactive bands than an extract from uncooked fish. IgE binding to these proteins could not be inhibited by an extract from uncooked fish. In contrast to a raw fish extract, the cooked extract showed higher resistance to pepsinolysis. The stability of Lep w 1 to thermal denaturation and digestion explains the high allergenicity of whiff.
Absorption, metabolism, and excretion of green tea flavan‐3‐ols in humans with an ileostomy
Authors: Stalmach Angélique , Mullen William , Steiling Heike , Williamson Gary , Lean Michael E. J. , Crozier Alan
Published: November 2009

Green tea containing 634 μmol of flavan‐3‐ols was ingested by human subjects with an ileostomy. Ileal fluid, plasma, and urine collected 0–24 h after ingestion were analysed by HPLC‐MS. The ileal fluid contained 70% of the ingested flavan‐3‐ols in the form of parent compounds (33%) and 23 metabolites (37%). The main metabolites effluxed back into the lumen of the small intestine were O‐linked sulphates and methyl‐sulphates of (epi)catechin and (epi)gallocatechin. Thus, in subjects with a functioning colon substantial quantities of flavan‐3‐ols would pass from the small to the large intestine. Plasma contained 16 metabolites, principally methylated, sulphated, and glucuronidated conjugates of (epi)catechin and (epi)gallocatechin, exhibiting 101–256 nM peak plasma concentration and the time to reach peak plasma concentration ranging from 0.8 to 2.2 h. Plasma pharmacokinetic profiles were similar to those obtained with healthy subjects, indicating that flavan‐3‐ol absorption occurs in the small intestine. Ileostomists had earlier plasma time to reach peak plasma concentration values than subjects with an intact colon, indicating the absence of an ileal brake. Urine contained 18 metabolites of (epi)catechin and (epi)gallocatechin in amounts corresponding to 6.8±0.6% of total flavan‐3‐ol intake. However, excretion of (epi)catechin metabolites was equivalent to 27% of the ingested (−)‐epicatechin and (+)‐catechin.
An optimally convergent discontinuous Galerkin‐based extended finite element method for fracture mechanics
Authors: Shen Yongxing , Lew Adrian
Published: November 2009

The extended finite element method (XFEM) enables the representation of cracks in arbitrary locations of a mesh. We introduce here a variant of the XFEM rendering an optimally convergent scheme. Its distinguishing features are as follows: (a) the introduction of singular asymptotic crack tip fields with support on only a small region around the crack tip (the enrichment region), (b) only one and two enrichment functions are added for anti‐plane shear and planar problems, respectively and (c) the relaxation of the continuity between the enrichment region and the rest of the domain, and the adoption of a discontinuous Galerkin (DG) method therein. The method is provably stable for any positive value of a stabilization parameter, and by weakly enforcing the continuity between the two regions it eliminates ‘blending elements’ partly responsible for the suboptimal convergence of some early XFEMs. Moreover, the particular choice of enrichment functions results in a surprisingly sparse stiffness matrix that remains reasonably conditioned as the mesh is refined. More importantly, the stress intensity factors can be extracted with a satisfactory accuracy as primary unknowns. Quadrature strategies required for the optimal convergence are also discussed. Finally, the DG method was modified to retain stability based on an inf‐sup condition. Copyright © 2009 John Wiley & Sons, Ltd.
Additional evidence for the affective dimension of dyspnea in patients with COPD
Authors: Carrieri‐Kohlman Virginia , Donesky‐Cuenco DorAnne , Park Soo Kyung , Mackin Lynda , Nguyen Huong Q. , Paul Steven M.
Published: November 2009

The primary purpose of this secondary analysis was to determine whether 103 participants with chronic obstructive pulmonary disease rated the affective dimension of dyspnea (dyspnea‐related anxiety and dyspnea‐related distress) separately from the sensory dimension (intensity) during baseline exercise testing conducted as part of a randomized clinical trial. A secondary purpose was to determine if dyspnea‐related anxiety and distress were rated distinctly different from other measurements of anxiety. At the end of a 6‐minute walk and an incremental treadmill test, participant ratings of the magnitude of dyspnea‐related anxiety and distress on the Modified Borg Scale were significantly different from their ratings of the intensity of dyspnea. Dyspnea‐related anxiety and distress also appeared to be concepts independent from measures of state anxiety, negative affect, and anxiety before a treadmill test. © 2009 Wiley Periodicals, Inc. Res Nurs Health 33:4–19, 2010
Increasingly restrictive definitions of hyperkalemia outcomes in a database study: effect on incidence estimates
Authors: Raebel Marsha A. , Ross Colleen , Cheetham Craig , Petersen Hans , Saylor Gwyn , Smith David H. , Wright Leslie A. , Roblin Douglas W. , Xu Stanley
Published: November 2009

Purpose

To determine the incidence of hyperkalemia‐associated adverse outcomes among ambulatory patients with diabetes newly initiating renin‐angiotensin‐aldosterone system (RAAS) inhibitor therapy and to examine to what extent increasingly restrictive definitions of hyperkalemia‐associated outcomes influenced incidence estimates.

Methods

Retrospective cohort study of 27 355 individuals with diabetes who were new users of RAAS inhibitors at three integrated healthcare systems.

Results

Using the least restrictive definition of hyperkalemia‐associated outcome, an ambulatory visit (AV), inpatient hospitalization (IP), or emergency department (ED) visit co‐occurring within 7 days of coded hyperkalemia diagnosis and/or potassium concentration of ≥5.5 mmol/L, the incidence rate of hyperkalemia was 30.1 per 1000 person‐years (p‐y). Restricting to only IP or ED visits co‐occurring within 24 hours of coded diagnosis and/or potassium ≥6 mmol/L, the incidence rate was 10.2 per 1000 p‐y. When this latter definition was further restricted by removing available potassium laboratory values, the incidence rate declined to 9.5 per 1000 p‐y.

Conclusions

Modifying the definition of hyperkalemia‐associated outcome resulted in up to threefold differences in incidence rate estimates. Our results demonstrate the value of including potassium laboratory results and AVs in identifying hyperkalemia from electronic data. Comparing incidence estimates across published studies requires consideration of differences in outcome definitions. Copyright © 2009 John Wiley & Sons, Ltd.
Theoretical and visual study of bubble dynamics in foam injection molding
Authors: Mahmoodi Mehdi , Behravesh Amir Hossein , Rezavand Seyyed Abdol Mohammad , Golzar Mohammad
Published: November 2009

This article presents an experimental observation and a theoretical prediction of bubble dynamics in foam injection molding process with a main focus on the cell collapse phenomenon under pressure. Using a visualizing setup, cell growth behavior under a nonisothermal condition was monitored. In conjunction with the growth behavior, dynamics of cell collapse under different pressures and the effect of growing time on collapse behavior and final cell size were studied. Theoretical simulation of bubble behavior included power law model, which predicted bubble dynamics during foaming process. The results show that collapse phenomenon strongly depends on both exerted holding pressure and growth time. The presented model can also give a reasonable prediction of growth and collapse of cells and could give insight to control of cell size in injection foaming process. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A developmental typology of adolescent personality
Authors: Klimstra Theo A. , Hale William W. , Raaijmakers Quinten A. W. , Branje Susan J. T. , Meeus Wim H. J.
Published: November 2009

The purpose of the current study is to examine whether Block's personality types (i.e. Resilients, Undercontrollers and Overcontrollers) are replicable as developmental trajectories. We applied a Latent Class Growth Analysis (LCGA) framework to five‐ annual‐wave data on a sample of early to middle adolescents (n = 923). Our results showed that Block's Resilients, Undercontrollers and Overcontrollers are indeed replicable as developmental trajectories across adolescence. These developmental types were related to problem behaviour in a similar way as types found in studies using cross‐sectional data. As such, Resilients reflected low levels of problem behaviour, Undercontrollers had high levels of delinquency and Overcontrollers had high levels of depression. Implications and suggestions for further research are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Sodium 1, 4‐dihydroxy‐9, 10‐anthraquinone‐ 2‐sulphonate interacts with calf thymus DNA in a way that mimics anthracycline antibiotics: an electrochemical and spectroscopic study
Authors: Guin Partha Sarathi , Das Saurabh , Mandal P. C.
Published: November 2009

The anthracycline drugs, adriamycin and daunorubicin, efficient in the treatment of various human cancers, form strong intercalation complexes with DNA. The therapeutic efficiency and toxic properties of the drugs are associated with electron transfer processes, which correlate well with the redox behaviour of the compounds. Sodium 1,4‐dihydroxy 9,10‐anthraquinone‐2‐sulphonate (sodium quinizarin‐2‐sulphonate, NaLH2) (Na‐Qz‐2S) is a molecule that resembles anthracycline drugs and has a simpler structure in comparison to these drugs. Two electrons in the course of chemical action reduce this molecule like the anthracyclines. Electrochemical methods were used to identify this process. UV‐Vis and fluorescence spectroscopy were used to analyse binding of the compound to calf thymus DNA. The binding constant and site size were evaluated for Na‐Qz‐2S and the same compared to that of the anthracyclines. Such comparisons are essential in order to understand whether the simpler hydroxy‐anthraquinones can be a substitute for anthracycline drugs in cancer chemotherapy. Copyright © 2009 John Wiley & Sons, Ltd.
Reactivity of sodium arenesulfinates in the substitution reaction to γ‐functionalized allyl bromides
Authors: Khamis Galina , Stoeva Stoyanka , Aleksiev Dimitar
Published: November 2009

The kinetics of nucleophilic bimolecular substitution reactions of γ‐functionalized allyl bromides with non‐substituted and p‐substituted sodium arenesulfinates has been studied. Both the structure of allyl bromides and nucleophilicity of arenesulfinate ions exerted a significant effect on the values of the kinetic parameters such as the second‐order rate constants k, activation energy EA, and changes in the entropy ΔS≠, enthalpy ΔH≠, and free energy ΔG≠ of the formation of the activated complex from reactants. Based on the evaluation of kinetic parameters, the reactants could be arranged, according to their decreasing reactivity in the SN2‐reactions as follows: p‐toluenesulfinate ion > benzenesulfinate ion > p‐chlorobenzenesulfinate ion and 4‐bromo‐2‐butenenitrile > 1,3‐ dibromopropene, respectively. Comparison was also made between the kinetic data obtained and some delocalization reactivity indexes for both the substrates and nucleophiles. The enthalpy–entropy compensation effect was observed for the reactions of sodium arenesulfinates with γ‐functionalized allyl bromides. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of substituents on activation parameters in SN2 reactions at aliphatic carbon in solution
Authors: Vlasov Vladislav M.
Published: November 2009

Changes of the activation parameters in aliphatic SN2 reactions with anionic and neutral nucleophiles in various solvents, ΔH≠ and ΔS≠, were correlated with σ constants of the substituents. The resultant δΔH≠ and δΔS≠ reaction constants are linearly related for variations of substituents at the substrate, leaving group and nucleophile. Correlations of δΔH≠ versus δΔS≠ allow the estimation of the contribution of changes of the internal enthalpy, δΔH, to the enthalpy reaction constant, δΔH≠, which gives a single linear dependence on the Hammett ρ reaction constants. The deviations from the dependence of δΔH versus ρ can be interpreted in terms of changes in the transition state structure in SN2 reactions. The results obtained show that the substituent effects on the charge development in the transition state are governed by the magnitude of δΔH. Copyright © 2009 John Wiley & Sons, Ltd.
The production of high polymer to surfactant microlatexes
Authors: Moraes Raul P. , Hutchinson Robin A. , McKenna Timothy F. L.
Published: November 2009

Starved‐feed microemulsion polymerization of styrene was investigated. The influence of the type (SDS or Dowfax 2A1) and concentration of anionic surfactant on the final particle size of latex made by the polymerization of microemulsions of styrene was studied. In addition, the influence of 1‐pentanol and acrylic acid as cosurfactants was examined. Latexes with 20% solids content and polymer to surfactant ratio of 22 were produced, with a particle diameter of 42 nm and very low polydispersity indexes. Smaller particles are produced using SDS than Dowfax 2A1 for the same weight fraction of surfactant; however, similar particle sizes were obtained with the same molar concentrations of SDS and Dowfax 2A1. Further shot additions of monomer increased solids level as high as 40% and polymer to surfactant ratios greater than 40, with particles remaining monodisperse with average diameter smaller than 60 nm. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 48–54, 2010
Modifying an amorphous polymer to a fast crystallizing semi‐crystalline material by copolymerization with monodisperse amide segments
Authors: Stephen Ranimol , Gibon Cécile M. , Weber Martin , Gaymans Reinoud J.
Published: November 2009

Segmented block copolymers of polysulphone with monodisperse amide segments were synthesized by a melt and a solution polymerization method. Both triblock and multiblock copolymers were prepared. The length of the difunctional polysulphone was varied from 2000 to 20,000 g/mol. The monodisperse amide segment was the tetra‐amide T6T6T based on terephthalic acid (T) and hexamethylene diamine (6) units. The main goal of this work was to study if the high Tg amorphous polysulphone could be modified to a high Tg semi‐crystalline PSU‐T6T6T copolymer. The copolymers were characterized by viscosity measurements, NMR, FTIR, MALDI‐TOF, DSC, and DMA. Depending on the amide concentration in the copolymers the T6T6T melting temperatures ranged between 220 and 270 °C and thus the crystallization window was small 50–100 °C. From the FTIR results, it was revealed that the crystallinity of the T6T6T segments in the copolymer could be very high, up to 92–97%. The T6T6T has crystallized out into nanoribbons with a high aspect ratio. These high Tg semi‐crystalline copolymers had a high dimensional and solvent resistance. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 63–73, 2010
Syntheses, properties, and field‐effect transistors of small band gap quinoxaline‐ and thienopyrazine‐vinylene/ethynylene conjugated polymers
Authors: Chueh Chu‐Chen , Lai Mei‐Hsiu , Tsai Jung‐Hsun , Wang Chih‐Feng , Chen Wen‐Chang
Published: November 2009

New conjugated copolymers of quinoxaline (AQ) and thienopyrazine (ATP) with vinylene (V) or ethynylene (E), poly[2,3‐bis(4‐(2‐ethylhexyloxy)phenyl)‐quinoxaline vinylene] (PAQV), poly[2,3‐bis(4‐(2‐ethylhexyloxy)phenyl)‐quinoxaline ethynylene)] (PAQE), poly[2,3‐bis(4‐(2‐ethylhexyloxy)phenyl)‐thieno[3,4‐b]pyrazine vinylene] (PATPV), and poly[2,3‐bis(4‐(2‐ethylhexyloxy)phenyl)‐thieno[3,4‐b]pyrazine ethynylene] (PATPE), were successfully synthesized by Stille coupling reaction. The optical band gaps of the PAQV, PAQE, PATPV, and PATPE were 1.86, 2.00, 0.88, and 0.90 eV, respectively, whereas the electrochemical band gaps were 1.99, 2.06, 1.00, and 1.06 eV, respectively. The reduced steric hindrance by the incorporation of the V or E linkage or the intramolecular charge transfer between the acceptor and the V or E linkage led to the small band gap. The AQ/ATP‐vinylene copolymers exhibited much higher vis/near infrared absorption intensity than the AQ/ATP‐ethynylene suggested the stronger π–π* transition intensity in the former and led to better charge‐transporting characteristics. The saturation field‐effect hole mobilities of the PATPV were 2.1 × 10−3, 1.7 × 10−2, and 1.1 × 10−2 cm2 V−1 s−1 on bare, octyltrichlorosilane (OTS)‐treated, and octadecyltrichlorosilane(ODTS)‐treated SiO2, respectively, with on‐off current ratios of 35, 6.02 × 102, and 7.56 × 102. On the other hand, the estimated field‐effect transistor hole mobility of the PATPE was in the range of 1.7 × 10−6–8.1 × 10−4 cm2 V−1 s−1, which was significantly smaller than those of the PATPV. The small band gaps and high charge carrier mobility of the prepared copolymers suggested their potential applications for near‐infrared electronic and optoelectronic devices. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 74–81, 2010
Synthesis, characterization, and electroluminescence of polyfluorene copolymers containing T‐shaped isophorone derivatives
Authors: Park Moo‐Jin , Lee Jonghee , Jung In Hwan , Park Jong‐Hwa , Kong Hoyoul , Oh Ji‐Young , Hwang Do‐Hoon , Shim Hong‐Ku
Published: November 2009

We have successfully synthesized a series of new fluorene‐based copolymers, poly[(9,9‐bis(4‐octyloxy‐phenyl)fluorene‐2,7‐diyl)‐co‐[2(3{2[4(2{4[bis(bromophenyl‐4yl) amino]phenyl}vinyl)‐2,5‐bisoctyloxyphenyl]vinyl}‐5,5‐dimethyl‐cyclohex‐2‐enylidene)malononitrile] (PFTBMs), with varying molar ratios of the low‐energy band gap comonomer, 2(3{2[4(2{4[bis(4‐bromophenyl)amino]phenyl}vinyl)‐2,5‐bisoctyloxyphenyl]vinyl}‐5,5‐dimethyl‐cyclohex‐2‐enylidene)malononitrile (BTBM). To prepare BTBM (which has a T‐shaped structure) from triphenylamine, dialkoxy phenyl, and isophorone, we introduced three individual segments of an isophorone derivative containing two cyanide groups at the carbonyl position, a dialkoxy phenyl group for increased solubility, and a triphenyl amine for effective charge transfer. Furthermore, we introduced vinyl linkages between each segment to increase the length of π‐conjugation. The synthesized polyfluorene copolymers with the BTBM, PFTBMs, were synthesized via palladium‐catalyzed Suzuki coupling reactions. The photoluminescence emission spectra of the synthesized polymers in solution did not show significant energy transfer from PBOPF segments to the BTBM units. Light‐emitting devices based on these polymers were fabricated with an indium tin oxide/poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/polymers/Balq/LiF/Al configuration. Examination of the electroluminescence emission of the synthesized polymers showed that the maximum wavelength shifted continuously toward long wavelengths with as the number of BTBM units in the polymer main chain was increased. In particular, a device using PFTBM 05 exhibited a maximum brightness of 510 cd/m2 and a maximum current efficiency of 0.57 cd/A. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 82–90, 2010
Synthesis and properties of new fluorinated polymers bearing pendant imidazole groups for fuel cell membranes operating over a broad relative humidity range
Authors: Frutsaert Guillaume , Delon Louis , David Ghislain , Améduri Bruno , Jones Deborah J. , Glipa Xavier , Rozière Jacques
Published: November 2009

New alternating copolymers comprising a chlorotrifluorinated backbone and imidazole‐terminated pendant ethylene oxide groups have been prepared with a view to their use as a component of proton‐conducting membranes in polymer electrolyte fuel cells. A vinyl ether containing an imidazole (Imi) function protected by a benzyl group (BVI) was first synthesized in a three‐step reaction. It was then copolymerized in solution with chlorotrifluoroethylene (CTFE) by conventional radical copolymerization leading to alternating poly(BVI‐alt‐CTFE) copolymers in good yields. Deprotection of the benzyl group under hydrogen produced a chlorotrifluorinated poly(Imi‐alt‐CTFE) copolymer. The polymer was subsequently used to form blend membranes with sulfonated poly(ether ether ketone) (sPEEK). The conductivity of blend membranes of poly (Imi‐alt‐CTFE) with sPEEK lies in the range of 4–10 mS cm−1 at 40–70 °C and, for blend membranes rich in poly(Imi‐alt‐CTFE), is little dependent on relative humidity between 30 and 100%. It is surmised that the polymer and membrane composition favor microstructural phase separation into chlorotrifluorinated polymer backbone domains and regions in which imidazole groups are clustered. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 223–231, 2010
Multiarm star block and multiarm star mixed‐block copolymers via azide‐alkyne click reaction
Authors: Durmaz Hakan , Dag Aydan , Erdogan Elif , Demirel A. Levent , Hizal Gurkan , Tunca Umit
Published: November 2009

The synthesis of multiarm star block (and mixed‐block) copolymers are efficiently prepared by using Cu(I) catalyzed azide‐alkyne click reaction and the arm‐first approach. α‐Silyl protected alkyne polystyrene (α‐silyl‐alkyne‐PS) was prepared by ATRP of styrene (St) and used as macroinitiator in a crosslinking reaction with divinyl benzene to successfully give multiarm star homopolymer with alkyne periphery. Linear azide end‐functionalized poly(ethylene glycol) (PEG‐N3) and poly (tert‐butyl acrylate) (PtBA‐N3) were simply clicked with the multiarm star polymer described earlier to form star block or mixed‐block copolymers in N,N‐dimethyl formamide at room temperature for 24 h. Obtained multiarm star block and mixed‐block copolymers were identified by using 1H NMR, GPC, triple detection‐GPC, atomic force microscopy, and dynamic light scattering measurements. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 99–108, 2010
AGET ATRP of acrylonitrile using 1,1,4,7,10,10‐hexamethyltriethylenetetramine as both ligand and reducing agent
Authors: Chen Hou , Wang Chunhua , Liu Delong , Song Yuting , Qu Rongjun , Sun Changmei , Ji Chunnuan
Published: November 2009

Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) initiated by ethyl 2‐bromoisobutyrate was approached for the first time using 1,1,4,7,10,10‐hexamethyltriethylenetetramine (HMTETA) and 1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) as both ligand and reducing agent. AGET ATRP of AN with HMTETA as both ligand and reducing agent was better controlled than with PMDETA as both ligand and reducing agent under the same experimental conditions. With an increase content of HMTETA, the polymerization provided an accelerated reaction rate and a broader polymer molecular weight distribution. The rate of polymerization with DMF as solvent was faster than with acetonitrile, cyclohexanone, toluene, and xylene as solvents. The polymerization apparent activation energy was calculated to be 45.7 kJ mol−1. The end functionality of polyacrylonitrile (PAN) was confirmed by 1H NMR spectroscopy. The living feature of PAN was verified by chain extensions of PAN with methyl methacrylate and AN. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 128–133, 2010
Synthesis and nonlinear optical properties of side chain liquid crystalline polymers containing azobenzene push–pull chromophores
Authors: Alicante Raquel , Cases Rafael , Forcén Patricia , Oriol Luis , Villacampa Belén
Published: November 2009

Azobenzene monomeric precursors bearing piperazine as donor moiety with different withdrawing groups and derived side chain polymethacrylates have been prepared and characterized. Monomers having terminal cyano or nitro groups, and the corresponding polymers, exhibited smectic A phases. Linear and nonlinear optical properties of every monomer and thin films of the cyano polymer (pol‐PZ‐CN) have been also studied. UV‐vis spectroscopy revealed out‐of‐plane orientation in the as prepared films, as confirmed by waveguide refractive index measurements. Moreover, absorption spectra indicated the presence of azo aggregates in these films. The initial molecular arrangement has been modified by applying thermal annealing within the mesophase range and UV‐blue irradiation. Although thermal annealing resulted in a significant amplification of the out‐of‐plane optical anisotropy due to thermotropic self‐organization of side chain azo moieties, irradiation with 440 nm light induced some disruption of aggregates. The nonlinear optical response of Corona poled films has been studied by second harmonic generation measurements, and the influence of the molecular arrangement on the nonlinear dij coefficients has been analyzed. The more efficient poling corresponded to preirradiated films. In any case, a noticeable degree of polar order (70% of the initial d33 value) remained for several months after the poling in films kept at RT. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 232–242, 2010
Morphology and physical properties of a novel Ramie‐PU blended nonwoven by electrospinning: The effect of cosolvent ratio
Authors: Peng Zhiqin , Yoshida Yoichiro , Sukigara Sachiko
Published: November 2009

A novel macro/nano blended nonwoven with excellent physical properties was prepared by electrospinning polyurethane (PU) nanofibers onto the surface of ramie webs under different weight ratios of N,N‐dimethylacetamide (DMAc)/acetone cosolvents. The ratio of cosolvents has a significant influence on the morphology, tensile properties, resilience, and thermal properties of the resultant samples. Bead‐free and fine interconnected nanofibers were obtained with an increase of acetone content up to 60 wt%. The total physical properties of the blended nonwovens were optimal for a DMAc/acetone ratio of 40/60, in which the tensile load at break, extension at break and Young's modulus were 441, 54, and 256% higher than that of pure ramie web, respectively. The resilience of the blended nonwovens was ∼20% higher than that of nonblended ramie web. The significant improvement of physical properties may be due to the good connection between PU nanofiber membranes and ramie webs and the molecular chain structure differences, interconnected structural differences, and high extensibility of PU nanofibers, according to the results of crystallization by differential scanning calorimetry (DSC) and morphological observation by scanning electronic microscopy (SEM). © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1–14, 2010
Crystallization behavior of isotactic propylene‐1‐hexene random copolymer revealed by time‐resolved SAXS/WAXD techniques
Authors: Mao Yimin , Zuo Feng , Keum Jong Kahk , Hsiao Benjamin S. , Thurman Derek W. , Tsou Andy H.
Published: November 2009

The crystallization behavior of isotactic propylene‐1‐hexene (PH) random copolymer having 5.7% mole fraction of hexene content was investigated using simultaneous time‐resolved small‐angle X‐ray scattering (SAXS) and wide‐angle X‐ray diffraction (WAXD) techniques. For this copolymer, the hexene component cannot be incorporated into the unit cell structure of isotactic polypropylene (iPP). Only α‐phase crystal form of iPP was observed when samples were melt crystallized at temperatures of 40 °C, 60 °C, 80 °C, and 100 °C. Comprehensive analysis of SAXS and WAXD profiles indicated that the crystalline morphology is correlated with crystallization temperature. At high temperatures (e.g., 100 °C) the dominant morphology is the lamellar structure; while at low temperatures (e.g., 40 °C) only highly disordered small crystal blocks can be formed. These morphologies are kinetically controlled. Under a small degree of supercooling (the corresponding iPP crystallization rate is slow), a segmental segregation between iPP and hexene components probably takes place, leading to the formation of iPP lamellar crystals with a higher degree of order. In contrast, under a large degree of supercooling (the corresponding iPP crystallization rate is fast), defective small crystal blocks are favored due to the large thermodynamic driving force and low chain mobility. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 26–32, 2010
Fluorescence spectroscopy and thermal relaxation processes of anthracenyl‐labeled polysiloxanes
Authors: Domingues Raquel Aparecida , Yoshida Inez Valéria Pagotto , Atvars Teresa Dib Zambon
Published: November 2009

A fluorescent silicone network was prepared by a hydrosilylation reaction using poly(dimethylsiloxane‐co‐methylhydrogensiloxane) terminated by dimethylhydrogensilyloxy groups, poly(dimethylsiloxane‐co‐methylvinylsiloxane) terminated by dimethylvinylsilyloxy groups and 9‐vinylanthracene, as the fluorescent group. These silicone‐based materials were strongly fluorescent. Steady state emission was a convenient technique to prove that reaction occurred, based on the blue‐shift of the emission from anthracenyl moieties compared with the 9‐vinylanthracene. Thermal transitions were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and by fluorescence spectroscopy, indicating that networks with and without lumophores had similar thermal properties. Networks with and without lumophores had the same swelling capability in toluene. Fluorescence spectroscopy was a more sensitive technique to the onset of the glass transition temperature (T = 145 K) than DSC or DMA. Nevertheless, the crystallization temperature at 192 K was determined more precisely by DSC, and the melting point at 237 K was indentified more clearly by both DSC and DMA. These three techniques provided complementary information about transitions in silicone networks. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 74–81, 2010
The effects of rigid polystyrene particles on the glass transition characteristics and mechanical wave attenuation of styrene‐butadiene rubber: Particle size and acoustic mismatch
Authors: Faghihi Farhad , Mohammadi Naser , Haghgoo Majid
Published: November 2009

Glass transition characteristics and mechanical wave attenuation of the neat and filled styrene‐butadiene rubber (SBR) containing 10 wt % of rigid monosize polystyrene particles of various diameters from several hundred microns down to several tens of nanometers were investigated by dynamic mechanical thermal analysis, impedance tube, and ultrasonic spectroscopy. The results showed the matrix damping capacity and the breadth of glass transition increase by reducing the size of rigid particles due to the matrix‐particles interfacial area increase as the major governing parameter. Matrix glass transition broadening toward higher temperatures was attributed to the increased dynamic heterogeneity induced by fillers, whereas the damping capacity increase was assigned to contribution of interfacial friction loss mechanism. The proposed postulation was confirmed based on the calculated temperature distribution of the relaxing matrix volume fraction. Sound wave attenuation by the matrix and PS particles filled systems led to a broad absorption peak for the former and appearance of a secondary absorption peak at lower frequencies for the latter. Intensity of this secondary peak was highest for the system containing PS nanoparticles. Finally, ultrasonic attenuation enhanced by the PS particle size to wavelength ratio increase according to αsca ∼ (d/λ)0.38 scaling law and declined by replacing the dense particles with larger hollow PS particles. Comparison of the normalized attenuation of the PS particle filled SBR in various mechanical wave attenuation regimes implied low sensitivity to particle size in vibration, mild differentiation in the sound, and finally severe differentiation in the ultrasound regimes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 82–88, 2010
Plasma‐Mediated Modification of Austenitic Stainless Steel: Application to the Prevention of Yeast Adhesion
Authors: Saulou Claire , Despax Bernard , Raynaud Patrice , Zanna Sandrine , Marcus Philippe , Mercier‐Bonin Muriel
Published: November 2009

The work is focused on defining a stainless steel surface treatment to prevent microbial adhesion. The yeast Saccharomyces cerevisiae was selected as the model for eukaryotic cells. Different surface cleaning procedures, including chemical and plasma‐mediated treatments, were studied. Detachment experiments displayed no modification in yeast adhesion, despite significant variations in the physico‐chemical properties of the solid surface. Plasma‐mediated thin coatings (≈375 nm) were then deposited on stainless steel applying hexamethyldisiloxane/oxygen plasma. FT‐IR study revealed a dense SiOSi network, while XPS analysis detected no more iron or chromium at the extreme surface. Detachment experiments demonstrated that these films were successful in preventing cell adhesion, due to a barrier effect.

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Tip60 promotes prostate cancer cell proliferation by translocation of androgen receptor into the nucleus
Authors: Shiota Masaki , Yokomizo Akira , Masubuchi Daisuke , Tada Yasuhiro , Inokuchi Junichi , Eto Masatoshi , Uchiumi Takeshi , Fujimoto Naohiro , Naito Seiji
Published: November 2009

BACKGROUND

There are currently few effective therapies for castration‐resistant prostate cancer (CRPCa). CRPC which is resistant to castration is thought to result from increased activation of the androgen/androgen receptor (AR) signaling pathway, which may be augmented by AR coactivators.

METHODS

Luciferase reporter assay, Western blotting, quantitative real‐time polymerase chain reaction, fluorescence microscopy, cell proliferation assay, and flow cytometry for cell‐cycle analysis were used to resolve a role of Tip60 regulating AR in PCa cells.

RESULTS

Tip60 regulated transcriptions of AR target genes androgen independently. Tip60 knockdown induced translocation of AR into the cytoplasm. Acetylation‐mimicking mutations in the nuclear localization signal sequence caused AR protein to mainly localize in the nucleus despite androgen starvation, whereas non‐acetylation‐mimicking mutations caused AR to mainly localize in the cytoplasm despite androgen stimulation. Tip60 overexpression in castration‐resistant LNCaP derivative CxR cells resulted in increases in the acetylated form of AR and AR localization in the nucleus even without androgen. Consequently, Tip60 silencing suppressed the growth of AR‐expressing PCa cells by inducing cell‐cycle arrest at the G1 phase, similar to inhibition of androgen/AR signaling. Furthermore, Tip60 knockdown suppressed the cell growth of CxR cells.

CONCLUSIONS

Tip60 is involved in the proliferation of PCa cells as an AR coactivator. Modulation of Tip60 expression or function may be a useful strategy for developing novel therapeutics for PCa, even CRPC, which remain dependent on AR signaling, by overexpressing AR and its coactivators. Prostate 70: 540–554, 2010. © 2009 Wiley‐Liss, Inc.
Three conformational antibodies specific for different PSMA epitopes are promising diagnostic and therapeutic tools for prostate cancer
Authors: Wolf Philipp , Freudenberg Nikolaus , Bühler Patrick , Alt Karen , Schultze‐Seemann Wolfgang , Wetterauer Ulrich , Elsässer‐Beile Ursula
Published: November 2009

BACKGROUND

The prostate specific membrane antigen (PSMA) represents an attractive antigen for antibody‐based diagnostic and therapeutic intervention in prostate cancer, since it is highly restricted to the prostate and overexpressed in all tumor stages. The present work describes the in vitro characterization of the three anti‐PSMA monoclonal antibodies (mAbs) 3/A12, 3/E7, and 3/F11 in comparison to the mAb J591.

METHODS

The mAbs were tested for saturation and competitive binding on C4‐2 prostate cancer cells by flow cytometry. Immunohistochemical staining was conducted on frozen prostate normal and cancer tissues as well as on lymph node metastases. Similarly, potential crossreactivities were tested on a broad panel of human normal tissues.

RESULTS

The anti‐PSMA mAbs showed a strong binding to C4‐2 cells with mean half‐maximal saturation concentrations of about 14 nM for 3/A12, 17 nM for 3/E7, 9 nM for 3/F11, and 16 nM for J591. Competitive binding studies revealed that our three mAbs bind to different extracellular PSMA epitopes. The mAbs showed comparable staining of epithelial cells for all tested normal and tumorous prostate tissues. Extraprostatic staining was observed on secretory cells of the salivary glands and on the brush border of the duodenal columnar epithelium. J591 additionally showed positive staining of the normal breast epithelium.

CONCLUSIONS

Due to their specific binding characteristics, the anti‐PSMA mAbs 3/A12, 3/E7, and 3/F11 show great promise for diagnostic and therapeutic applications in prostate cancer. Prostate 70: 562–569, 2010. © 2009 Wiley‐Liss, Inc.
Downmodulation of Bcl‐2 sensitizes metastatic LNCaP‐LN3 cells to undergo apoptosis via the intrinsic pathway
Authors: Song Renduo , Harris Loleta D. , Pettaway Curtis A.
Published: November 2009

BACKGROUND

We explored the mechanisms of apoptosis after Bcl‐2 protein downmodulation in metastatic LNCaP‐LN3 cells (LN3).

METHODS

LNCaP, LNCaP‐Pro5 (Pro5) and LN3 cells were cultured in 5% charcoal‐stripped serum (CSS) or in R1881 (synthetic androgen) and bicalutamide (synthetic anti‐androgen) and growth inhibition was assessed. Expression levels of androgen receptor (AR) and Bcl‐2 were determined. LN3 cells were transfected with small interfering RNA Bcl‐2 (siRNA Bcl‐2) or control siRNA oligonucleotides. Rates of apoptosis and proliferation were obtained. Cytochrome c localization in treated and control cells was assessed ± cyclosporine A (CsA). Caspases 9, 3, and poly (ADP‐ribose) polymerase cleavage (PARP) were measured upon downmodulation of Bcl‐2; and cell growth inhibition in vitro after Bcl‐2 modulation combined with docetaxel chemotherapy was determined.

RESULTS

LN3 cells maintained growth under castrate conditions in vitro. AR protein amplification did not explain castrate‐resistant LN3 cell growth. Bcl‐2 protein levels in LN3 cells were significantly higher than in Pro5 cells, and were effectively downmodulated by siRNA Bcl‐2. Subsequently increased apoptosis and decreased proliferation mediated by cytochrome c was noted and this was reversed by CsA. siRNA Bcl‐2‐transfected LN3 cells exhibited elevated levels of caspases 9, 3, and PARP cleavage. Exposure of LN3 cells to docetaxel led to increased apoptosis, and simultaneous downmodulation of Bcl‐2 substantially enhanced this effect.

CONCLUSIONS

Downmodulation of Bcl‐2 in metastatic castrate‐resistant LNCaP‐LN3 cells led to apoptosis via a cytochrome c‐dependent pathway that was enhanced with docetaxel treatment. Prostate 70: 571–583, 2010. © 2009 Wiley‐Liss, Inc.
Structural and functional characterization of a promiscuous feruloyl esterase (Est1E) from the rumen bacterium Butyrivibrio proteoclasticus
Authors: Goldstone David C. , Villas‐Bôas Silas G. , Till Marisa , Kelly William J. , Attwood Graeme T. , Arcus Vickery L.
Published: November 2009

The release of polysaccharide from the plant cell wall is a key process to release the stored energy from plant biomass. Within the ruminant digestive system, a host of commensal microorganisms speed the breakdown of plant cell matter releasing fermentable sugars. The presence of phenolic compounds, most notably ferulic acid (FA), esterified within the cell wall is thought to pose a significant impediment to the degradation of the plant cell wall. The structure of a FA esterase from the ruminant bacterium Butyrivibrio proteoclasticus has been determined in two different space groups, in both the apo‐form, and the ligand bound form with FA located in the active site. The structure reveals a new lid domain that has no structural homologues in the PDB. The flexibility of the lid domain is evident by the presence of three different conformations adopted by different molecules in the crystals. In the FA‐bound structures, these conformations show sequential binding and closing of the lid domain over the substrate. Enzymatic activity assays demonstrate a broad activity against plant‐derived hemicellulose, releasing at least four aromatic compounds including FA, coumaric acid, coumarin‐3‐carboxylic acid, and cinnamic acid. The rumen is a complex ecosystem that efficiently degrades plant biomass and the genome of B. proteoclasticus contains greater than 130 enzymes, which are potentially involved in this process of which Est1E is the first to be well characterized. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Wood losses and economical threshold of Btk aerial spray operation against spruce budworm
Authors: Fournier Cédric , Bauce Éric , Dupont Alain , Berthiaume Richard
Published: November 2009

BACKGROUND: Spruce budworm, Choristoneura fumiferana (Clem.), causes cumulative defoliation and hence annual growth loss of the balsam fir, Abies balsamea (L.) Mill, host tree. Annual growth increments of mixed balsam fir stands were measured by stem analysis over a 9 year period (1994–2002), when Bacillus thuringiensis ssp. kurstaki (Btk) was applied to control spruce budworm defoliation. With this approach, it was possible to quantify the change in stand volume growth after aerial spray applications of Btk.

RESULTS: Differences between the periodic volume increment of protected and unprotected plots were statistically significant, while differences between protected and budworm‐free plots were not significant. After 9 years, the difference in periodic increment between protected and unprotected plots was 20 m3 ha−1, and the difference in periodic mortality was 20.5 m3 ha−1.

CONCLUSION: An economic assessment of Btk treatments indicates that biopesticide aerial spraying operations are justified, as they prevented substantial balsam fir mortality and growth losses over the 9 year study. Copyright © 2009 Society of Chemical Industry