bluuebunny/crossref_metadata_2025 huggingface dataset:
Getting a job is only half the battle: Maternal job loss and child classroom behavior in low‐income families
Authors: Hill Heather D. , Morris Pamela A. , Castells Nina , Walker Jessica Thornton
Published: February 2011

This study uses data from an experimental employment program and instrumental variables (IV) estimation to examine the effects of maternal job loss on child classroom behavior. Random assignment to the treatment at one of three program sites is an exogenous predictor of employment patterns. Cross‐site variation in treatment‐control differences is used to identify the effects of employment levels and transitions. Under certain assumptions, this method controls for unobserved correlates of job loss and child well‐being, as well as measurement error and simultaneity. IV estimates suggest that maternal job loss sharply increases problem behavior but has neutral effects on positive social behavior. Current employment programs concentrate primarily on job entry, but these findings point to the importance of promoting job stability for workers and their children. © 2011 by the Association for Public Policy Analysis and Management.
Kinetic study of polysulfide‐acrylate click reaction by DEA and DMA
Authors: Zhou Baijie , Shen Mingxia , Wang Qingjun , Chen Qingmin
Published: February 2011

The curing process of a polysulfide (PSF) with a triacrylate crosslinker in the presence of an amine catalyst at room temperature is a rapid Michael addition. This reaction was monitored by real‐time infrared spectrum (RTIR). The results of the RTIR show that the consumptions of thiol and acrylate are stoichiometric until 80% conversion, indicating the characteristics of a “click” reaction. Dielectric analyzer (DEA) and dynamic mechanical analyzer (DMA) were employed to investigate the curing kinetics from which the activation energies of this curing reaction were obtained and shown to correlate with each other. In addition, the influences of the types and amount of amine catalyst, the different molecular weights of PSFs, and the triacrylate crosslinkers were discussed. Copyright © 2011 John Wiley & Sons, Ltd.
Fabrication of highly porous starch monoliths and their application as green desiccants
Authors: Mi Xue , Wang Wenchao , Gao Jianping , Long Ying , Xing Fubao , Wang Xiaodong , Xu Fangqiang , You Xiudong , Li Shufeng , Liu Yu
Published: February 2011

Starch monoliths with oriented porous structures were developed from starches and glycerin as a plasticizer using unidirectional freeze‐drying technology. The morphology of the porous starch monoliths made from different starches was determined by scanning electron microscopy (SEM), and the porosity, mechanical properties and moisture absorption of the porous materials were evaluated. The results show that porous starch monoliths made from oxidized starch with 15% glycerin had good mechanical strength with the best moisture absorption. Increasing the starch concentration significantly improved their strength and increased the moisture absorption rate as well. The moisture absorption of the porous monolith made from oxidized starch is comparable with commonly used desiccants. The porous starch monoliths can successfully remove water from 95% ethanol to produce absolute ethanol due to their selective absorption for water. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation and modeling of the mechanical properties of graphite nanoplatelets based rubber nanocomposites for pressure sensing applications
Authors: Mahmoud Waleed E. , Al‐Ghamdi A. A. , Al‐Solamy Falleh R.
Published: February 2011

Acrylonitrile butadiene rubber (NBR) compounds filled with different concentrations of graphite nanoplatelets were experimentally investigated. The stress–strain curves of the nanocomposites were studied, which suggest good filler–matrix adhesion. The large reinforcement effect of the filler followed the Guth model for non‐spherical particles. The effect of graphite nanoplatelets on the cyclic fatigue and hysteresis was also examined. The loading and unloading stress–strain relationships for any cycle were described by applying Ogden's model for rubber nanocomposites. With this model for incompressible materials, expressions may be developed to predict the stress–strain relationship for any given cycle. The dissipated energy increased with graphite nanoplatelets concentrations and decrease with number of cycles. The rate of damage accumulation becomes marginal after first ten cycles. The rate of damage increases as the amount of graphite nanoplatelets increase into the rubber matrix. Copyright © 2011 John Wiley & Sons, Ltd.
Electropolymerization of layer‐by‐layer precursor polymer films
Authors: Waenkaew Paralee , Phanichphant Sukon , Advincula Rigoberto C.
Published: February 2011

The layer‐by‐layer (LbL) self‐assembly has been used to fabricate polymer thin films on any solid substrates. The multilayer polymer thin films are constructed by alternating adsorption of anionic and cationic polymers. Polyelectrolyte multilayer ultrathin films containing anionic poly[2‐(thiophen‐3‐yl)ethyl methacrylate‐co‐methacrylic acid]; P(TEM‐co‐MA) and cationic poly[4‐(9H‐carbazol‐9‐yl)‐N‐butyl‐4‐vinyl pyridium bromide]; P4VPCBZ, were fabricated. The growth of multilayer ultrathin films was followed by UV–Vis absorption spectrophotometer and surface plasmon resonance spectroscopy (SPR). The deposition of P(TEM‐co‐MA)/P4VPCBZ as multilayer self‐assembled ultrathin films regularly grow which showed linear growth of absorbance and thickness with increasing the number of layer pair. Cross‐linking of the layers was verified by cyclic voltammetry (CV), UV–Vis spectrophotometry and electrochemical surface plasmon resonance (EC‐SPR) spectroscopy with good electro‐copolymerizability. This was verified by spectroelectrochemistry. The SPR angular‐reflectivity measurement resulted in shifts to a higher reflectivity according to the change in the dielectric constant of the electropolymerized film. Copyright © 2011 John Wiley & Sons, Ltd.
Carbon nanocones/discs – a new type of filler to improve the thermal and mechanical properties of polymer films
Authors: Gofman Iosif V. , Abalov Ivan V. , Gladchenko Svetlana V. , Afanas'eva Nadezhda V.
Published: February 2011

The mechanical characteristics and thermal properties of composite films based on the thermally stable aromatic polyimide (PI) (PMDA‐ODA) and carbon nanocones/discs (CNC) were studied. The introduction of CNC to PMDA‐ODA leads to the substantial increase of film stiffness. The Young's modulus values of the composite films are somewhat higher than those of the previously characterized composite films of this PI filled with nanoclay, carbon nanofibers, and asbestos‐like hydrosilicate nanotubes. The introduction of CNC into PMDA‐ODA (concentrations of CNC were up to 15 vol%) does not cause any marked aggregation of nanoparticles. The presence of CNC in the PI matrix does not affect the glass transition temperature of the polymer but hinders chain mobility at temperatures above Tg. This behavior makes it possible to increase the working temperature range of the composite films containing more than 5 vol% of CNCs, up to the temperature of thermal decomposition. The introduction of CNC into PMDA‐ODA leads to dramatic (∼12 orders of magnitude) increase of active electrical conductivity of the material. Copyright © 2011 John Wiley & Sons, Ltd.
Structure and properties of chlorinated polyvinyl chloride graft copolymer with higher property
Authors: Xu Chao , Wang Shuangshuang , Shao Lu , Zhao Jiruo , Feng Ying
Published: February 2011

In this work, maleic anhydride (MAH) was grafted onto chlorinated polyvinyl chloride (CPVC) with high chlorine content (66 wt%) via in‐situ chlorinating graft copolymerization (ISCGC) to obtain the material with improved mechanical strength, softening point, and thermal stability of the material. The structure of the graft product (CPVC‐cg‐MAH) was characterized by FTIR, 1H NMR, GPC, and UV. CPVC‐cg‐MAH contains less vinylidene chloride (CCl2) units and double bond than corresponding CPVC. Meanwhile, the number–average molecular weight (Mn) and weight–average molecular weight (Mw) of CPVC‐cg‐MAH are increased, but distribution of molecular weight (Mw/Mn) is decreased. Then, the tensile strength and notched impact strength of CPVC‐cg‐MAH increased by 14.5 and 34.6%, respectively. Furthermore, the results of DMA, DSC, TG, and Vicat softening point showed that the loss peak of CPVC‐cg‐MAH was higher evidently than CPVC and moved to high temperature, the glass transition temperature (Tg) of CPVC‐cg‐MAH was consistent with CPVC, initial weight loss temperature, and maximum weight loss rate temperature of CPVC‐cg‐MAH increased by 7.2°C and 6.1°C, respectively, and the Vicat softening temperature of CPVC‐cg‐MAH increased by 15°C and up to 130°C. Copyright © 2011 John Wiley & Sons, Ltd.
Characterization of keratin–collagen 3D scaffold for biomedical applications
Authors: Balaji S. , Kumar Ramadhar , Sripriya R. , Rao Urmila , Mandal Abhishek , Kakkar Prachi , Reddy P. NeelaKanta , Sehgal Praveen Kumar
Published: February 2011

Fabrication of keratin–collagen (KC) 3D scaffold with improved thermal denaturation rate is reported. In vitro application of (KC) scaffold stimulates basic extra cellular matrix constituents. KC Scaffold considerably reduced undesirable properties of both collagen and keratin while collagen incorporation reduces the fragility with increases of strength and flexibility in the scaffold. In addition to this, the scaffold showed homogenous well‐interconnected pores in the range of 10–100 µm when observed in scanning electron microscope. Usage of keratin in KC scaffold offers increased biodegradation rate and higher denaturation rate in addition to its rapid cell growth with normal morphology ultimately reaching cell population of 3.9–9.7 million per cm3 after 48 hr in KC scaffold. Circular dichroism (CD) and Fourier transform spectroscopy (FT‐IR) of KC showed presence of helical structure of collagen and ß‐turns of keratin confirming retention of native structures of both the proteins KC scaffold showed good swelling behavior and water uptake. Our study strongly supports the superidity of KC scaffold over the collagen or keratin when they are independently used for tissue engineering applications. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and characterization of CNTs/PE micro‐nanofibers
Authors: Wang Hailian , Xiao Ru
Published: February 2011

Multiwalled carbon nanotubes (CNTs)/polyethylene micro‐nanofibers with content ranging from 0.5 to 10 wt% of CNTs were prepared for the first time by melt extrusion of immiscible blends with cellulose acetate butyrate (CAB) and subsequent removal of CAB matrix. The morphology development of dispersed phase was studied with samples collected at different zones in a twin‐screw extruder. The morphology of the CNTs in PE was found to be in forms of both individual and agglomerations. The average diameters of CNTs/PE nanofibers increased with increasing the CNTs content. The electrical conductivity of CNTs/PE nanofibers was studied and a percolation threshold of about 4 wt% was obtained. In addition, the crystalline structures of the CNTs/PE nanofibers were analyzed, indicating a decrease in the crystallinity with the addition of CNTs. The thermal properties of composite fibrils were also modified. This paper demonstrates a good approach for the preparation of CNTs/TP nanofibers by in situ microfibrillar formation. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and gas permeation properties of poly(vinyl chloride)‐graft‐poly(vinyl pyrrolidone) membranes
Authors: Yeon Seung Hyeon , Ahn Sung Hoon , Kim Jong Hak , Lee Ki Bong , Jeong Yujin , Hong Seong Uk
Published: February 2011

A series of amphiphilic graft copolymers consisting of poly(vinyl chloride) (PVC) main chains and poly(vinyl pyrrolidone) (PVP) side chains, i.e. PVC‐g‐PVP, was synthesized via atom transfer radical polymerization (ATRP), as confirmed by 1H NMR, FT‐IR spectroscopy, and gel permeation chromatography (GPC). Transmission electron microscope (TEM) and small angle X‐ray scattering (SAXS) analysis revealed the microphase‐separated structure of PVC‐g‐PVP and the domain spacing increased from 21.4 to 23.9 nm with increasing grafting degree. All the membranes exhibited completely amorphous structure and high Young's modulus and tensile strength, as revealed by wide angle X‐ray scattering (WAXS) and universal testing machine (UTM). Permeation experimental results using a CO2/N2 (50/50) mixture indicated that as an amount of PVP in a copolymer increased, CO2 permeability increased without the sacrifice of selectivity. For example, the CO2 permeability of PVC‐g‐PVP with 36 wt% of PVP at 35°C was about four times higher than that of the pristine PVC membrane. This improvement resulted from the increase of diffusivity due to the disruption of chain packing in PVC by the grafting of PVP, as confirmed by WAXS analysis. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of highly reactive polyisobutylene by selective polymerization with o‐cresol/AlCl3 initiating system
Authors: Zhang L. B. , Wu Y. X. , Zhou P. , Xu R. W.
Published: February 2011

Highly reactive polyisobutylenes (HRPIBs) with very large proportion (up to 95 mol%) of exo‐double bond end groups and number average molecular weight (Mn) of 5400–8500 Dalton (Da) could be successfully synthesized by the selective cationic polymerization of isobutylene (IB) from the mixed C4 fraction feed using o‐cresol/AlCl3 as initiating system at −20°C. A possible mechanism was proposed for the cationic polymerization process. The presence of large weakly coordinating counteranion in propagating species could lead to decreasing the possibility of the side transfer reactions via carbenium ion arrangements. This o‐cresol/AlCl3 initiating system exhibited extremely high selectivity toward IB polymerization in the mixed C4 fraction feed and a good property for rapid β‐proton abstraction from CH3 in the growing polyisobutylenes (PIBs) chain ends. High extent of α‐double bond end groups in HRPIBs prepared in the mixed C4 fraction feed could be comparable to that in those commercially produced by cationic polymerization of IB in inert solvent (e.g. hexane). To our knowledge, this is the first example to achieve HRPIBs via completely selective polymerization of IB from C4 mixed feed with AlCl3‐based initiating system, providing a potentially practical process for its simplicity and low costs. Copyright © 2011 John Wiley & Sons, Ltd.
Precipitation polymerization of 2‐hydroxyethyl methacrylate in supercritical carbon dioxide
Authors: Wang Xiao‐Hu , Cao Li‐Qin , Zhang Li‐Juan , Wang Ji‐De
Published: February 2011

We report the successful precipitation polymerization of 2‐hydroxyethyl methacrylate (HEMA) in supercritical carbon dioxide (scCO2) at pressures ranging from 15 to 27 MPa utilizing 2, 2′‐azobisisobutyronitrile (AIBN) as a free radical initiator. The effects of the reaction pressure, initiator concentration, monomer concentration, reaction temperature, and reaction time were investigated. Analyses by scanning electron microscopy (SEM) indicated that in all reaction conditions, polymerization in the absence of stabilizer led to the formation of large aggregates of partially coalesced particles, with diameters of approximate 1–10 µm. Analyses by gel permeation chromatography (GPC) indicated that for the reaction pressure, initiator concentration, monomer concentration, reaction temperature, and reaction time studied there are appreciable effect on product molecular weight. Copyright © 2011 John Wiley & Sons, Ltd.
Comparison of three cross‐linking agents for imprinting diethylstilbestrol in solid‐phase extraction
Authors: Wang Yongxiang , Liu Qiuming , Rong Fei , Fu Degang
Published: February 2011

Molecularly imprinted polymer (MIP) has been heavily studied for years. However, most efforts focused on functional monomer and particular study of cross‐linking agents on imprinting effect and pore structure is rare. In this paper, diethylstilbestrol (DES) imprinted polymers cross‐linked by three types of agents and their imprinting effects in solid‐phase extraction (SPE) were discussed. Evolution of UV spectral and simulation of cross‐linking agents or monomer mixed with DES revealed that there was a particular interaction between divinylbenzene and DES. Clear imprinting effects towards DES showed for divinylbenzene made imprinted polymer (DM), with imprinting factors up to 16.02 (STD = 2.20), while the other two imprinted polymers showed limited effects with imprinting factors of 4.95 (STD = 0.45) and 1.63 (STD = 0.54). Specific surface areas, pore volumes, and pore size distributions of the particles also confirmed that DM showed distinguished structure, and the average pore size of it was just fit the size of DES and bisphenol A (BPA), while no pore was found in divinylbenzene made blank polymer. Other imprinted and non‐imprinted polymers showed no pore or big pores relatively. These results show that the cross‐linking monomer is not merely an inert component for the MIPs, it could play a positive role in promoting interactions with the template to afford molecular recognition in imprinting DES. Copyright © 2011 John Wiley & Sons, Ltd.
How nano‐fillers affect thermal stability and flame retardancy of intumescent flame retarded polypropylene
Authors: Du Baoxian , Ma Haiyun , Fang Zhengping
Published: February 2011

Recent advances in flame retardant polymers have centered on the flame retardancy of nano‐fillers contained polymer nanocomposites. Among which, organo‐clay (OMMT), layered double hydroxides (LDHs), polyhedral oligomeric silsesquioxane (POSS), and carbon nanotubes (CNTs) have been reported and proved to be effective flame retardants for variable polymers. In this paper, a systematical study was executed on flame retarded polypropylene (PP) composites containing intumescent flame retardant (IFR) and the most popular nano‐fillers. Dispersion of the nano‐fillers was characterized by using transmission electron microscopy (TEM), the results revealed that all nano‐fillers dispersed homogeneously in PP matrix. The effects of nano‐fillers on thermal stability and flammable of PP were investigated by thermogravimetry (TG) and cone calorimetry tests, respectively. The results indicated that different nano‐fillers played different roles in thermal and flammability properties of composites. PP composites with OMMT gave the best reductions in heat release rate (PHRR) and endowed PP with relatively better flame retardancy. Copyright © 2011 John Wiley & Sons, Ltd.
Structural characterization and high‐temperature compressive creep of PTFE‐based composites filled with inorganic nanoparticles
Authors: Wang Zhichao , Kou Kaichang , Liu Zongwen , Zhang Dongna , Bi Hui , Chao Min , Zhao Qingxin
Published: February 2011

The PTFE‐based nanocomposites with various contents of inorganic nanoparticles (n‐AlN and n‐Si3N4) were prepared by cold compaction followed by free sintering. The results of scanning electron microscopy, differential scanning calorimetry, and X‐ray diffraction show that PTFE spherulite formed in the nanocomposites. When 2 wt% inorganic nanoparticles were added into the PTFE matrix, the crystallinity increased from 34.3% to 42.1% and 43.2%, respectively. Moreover, the interplanar distances for each crystal plane were enlarged and the grain sizes were smaller than that of pure PTFE. In addition, the mechanical and high‐temperature compressive creep properties were investigated. The results indicate that the introduction of inorganic nanoparticles largely increased the high‐temperature compressive creep resistance, and the maximal reduction of percentage of creep strain was up to 68%. The tensile strengths of the nanocomposites increased with increasing filler content when it was no more than 2%, and then decreased with the further increase of the filler content, whereas the elongations at break showed a reverse tendency. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and characterization of a novel terpolymer based on L‐lactide, glycolide, and trimethylene carbonate for specific medical applications
Authors: Davachi S. M. , Kaffashi B. , Roushandeh J. Mohammadi
Published: February 2011

The bioresorbable new terpolymers of L‐lactide, glycolide, and trimethylene carbonate were synthesized via ring‐opening polymerization reaction of the cyclic monomers using Stannous octoate as initiator. Glycolide and L‐lactide were prepared from their parent acids and then purified by multiple re‐crystallization from ethyl acetate. The thermal and mechanical properties of this polymer were characterized by means of thermogravimetry, differential scanning calorimetry, stress–strain measurements, and dynamic mechanical analysis. The glass transition temperature of the terpolymers changed from 33 to 51°C with composition in a predictable manner. The rheological properties of copolymers and molecular weight of each copolymer were determined showing good processability for making fibers. Using a mini‐extruder, it was possible to produce some filaments. The filaments produced at 140°C had appropriate ductility. The in vitro measurements, specifying the biological properties were also carried out. The sample with monomer composition LLA:GA:TMC = 60:34:6 showed a slower degradation rate than the one with LLA:GA:TMC = 54:34:12. The low‐toxicity bioresorbable terpolymers with good rheological and in vitro properties are the promising new materials for biomedical applications specially a new suture formulation. Copyright © 2011 John Wiley & Sons, Ltd.
Protein nanotubes bearing a magnetite surface exterior
Authors: Komatsu Teruyuki , Kobayashi Nao
Published: February 2011

This communication describes the synthesis and structure of multilayered protein nanotubes bearing a magnetite (Fe3O4) surface exterior, and their binding capability for zinc(II)‐protoporphyrin IX (ZnPP) in aqueous medium. The nanotubes were fabricated using an alternating layer‐by‐layer (LbL) assembly of human serum albumin (HSA) and poly‐L‐arginine (PLA) in a track‐etched polycarbonate (PC) membrane (pore size, 400 nm), which had been precoated in advance with Fe3O4 nanoparticles. Dissolution of the PC template yielded Fe3O4(PLA/HSA)3 nanotubes. SEM measurements revealed the formation of uniform hollow cylinders with 417 ± 16 nm outer diameter and 56 ± 7 nm wall thickness. TEM observations confirmed the homogeneous outer surface of Fe3O4. In an aqueous medium, the nanotubes captured ZnPP into the swollen wall. The ZnPP‐loaded protein nanotubes were collected by exposure to a magnetic field. Copyright © 2011 John Wiley & Sons, Ltd.
The influence of α‐zirconium phosphate on fire performance of EVA and PS composites
Authors: Lu Hongdian , Wilkie Charles A.
Published: February 2011

Composites of polystyrene (PS) and poly(ethylene‐co‐vinyl acetate) (EVA) with organically modified zirconium phosphate (OZrP) were prepared by melt blending. Their morphologies were assessed by X‐ray diffraction and transmission electron microscopy, while the thermal stability and flammability properties were characterized by thermogravimetric analysis and cone calorimetry. Increasing the OZrP content was not conducive to the formation of a nanostructure in EVA and poor dispersion of zirconium phosphate layers in PS at the nanometer level was observed. Increased thermal stability at high temperature and a slight reduction in peak heat release rate were found when OZrP was added to PS, while in EVA, deteriorated thermal stability and flame retardancy were observed. Unlike montmorillonite, the partial replacement of intumescent flame retardants (IFR) by 2% OZrP imparted a negative effect on the flammability of the EVA/IFR (23%)/OZrP (2%) composite, increasing the peak heat release rate of EVA/IFR (25%). The PS/IFR (18%)/OZrP (2%) composite with poly(styrene‐co‐maleic anhydride) (SMA) as compatibilizer exhibited better flame retardancy than PS/SMA/IFR (20%), prolonging the combustion process and increasing the time to peak heat release rate significantly. Copyright © 2011 John Wiley & Sons, Ltd.
A novel panel of protein biomarkers for predicting response to thalidomide‐based therapy in newly diagnosed multiple myeloma patients
Authors: Rajpal Rajesh , Dowling Paul , Meiller Justine , Clarke Colin , Murphy William G. , O'Connor Robert , Kell Malcolm , Mitsiades Constantine , Richardson Paul , Anderson Kenneth C. , Clynes Martin , O'Gorman Peter
Published: February 2011

Multiple myeloma (MM) is a heterogeneous group of disorders both genotypically and phenotypically. Response to thalidomide‐based induction therapy in newly diagnosed patients varies significantly in published clinical trials. Proteomic analysis was performed on 39 newly diagnosed MM patients treated with a thalidomide‐based regimen (22 responders; 17 non‐responders) using immunodepletion, 2‐D DIGE analysis and mass spectrometry. Zinc‐α‐2‐glycoprotein (ZAG), vitamin D‐binding protein (VDB), serum amyloid‐A protein (SAA) and β‐2‐microglobulin (B2M) had statistically significant higher concentrations in non‐responders compared to responders, while haptoglobin (Hp) had a lower concentration. ELISAs were used to validate the candidate protein biomarkers using unfractionated serum from 51 newly diagnosed MM patients (29 responders; 22 non‐responders). Using logistic regression, the best possible area under the curve (AUC) was 0.96 using ZAG, VDB and SAA in combination. Leave‐one‐out‐cross‐validation (LOOCV) indicated an overall predictive accuracy of 84% with associated sensitivity and specificity values of 81.8 and 86.2%, respectively. Subsequently, 16 of 22 thalidomide‐refractory patients successfully achieved complete response or very good partial response using second‐line treatment suggesting that the biomarker profile is specific to thalidomide response rather than identifying patients with MM refractory to all therapies. Using a novel panel of predictive biomarkers, the feasibility of predicting response to thalidomide‐based therapy in previously untreated MM has been demonstrated.
Proteomic analysis of heterosis during maize seed germination
Authors: Fu Zhiyuan , Jin Xining , Ding Dong , Li Yongling , Fu Zhongjun , Tang Jihua
Published: February 2011

Heterosis is observed for most phenotypic traits and developmental stages in many plants. In this study, the embryos, from germinating seeds after 24 h of soaking, for five elite maize hybrids and their parents were selected to unravel the genetic basis of heterosis using 2‐D proteomic method. In total, 257 (80.06%), 363 (58.74%), 351 (79.95%), 242 (54.50%), and 244 (46.30%) nonadditively expressed proteins were identified in hybrids Zhengdan 958, Nongda 108, Yuyu 22, Xundan 20, and Xundan 18, respectively. The nonadditive proteins were divided into above high‐parent (++; 811, 55.66%), high‐parent (+; 121, 8.30%), partial dominance (+−; 249, 17.09%), low‐parent (−; 30, 2.06%), below low‐parent (− −; 62, 4.26%), and D (different; 184, 12.63%) expression patterns. The observed patterns indicate the important roles of dominance, partial dominance, and overdominance in regulating seed germination in maize. Additionally, 54 different proteins were identified by mass spectrometry and classified into nine functional groups: metabolism (9), cell detoxification (8), unknown functional proteins (8), chaperones (7), signal transduction (6), development process (5), other (5), transporter (3), and stress response (3). Of these, the most interesting are those involved with germination‐related hormone signal transduction and the abscisic acid and gibberellin regulation networks.
Clarifying the signal network of salvianolic acid B using proteomic assay and bioinformatic analysis
Authors: Feng Li‐Xing , Jing Chun‐Jie , Tang Kai‐Lin , Tao Lin , Cao Zhi‐Wei , Wu Wan‐Ying , Guan Shu‐Hong , Jiang Bao‐Hong , Yang Min , Liu Xuan , Guo De‐An
Published: February 2011

Salvianolic acid B (SB) is a natural compound with protective effect against ischemia–reperfusion heart injury. However, the signal network of SB including both direct target proteins and downstream signal‐related proteins has not been clarified. In the present study, epidermal growth factor receptor (EGFR) was predicted to be the most possible direct protein target of SB by INVDOCK, a ligand–protein inverse‐docking algorithm. Possible signal‐related proteins of SB in H9C2 cells, including both under normal condition and under ischemia–reperfusion injury, were searched using 2‐DE analysis. Totally, 14 signal‐related proteins were found. Finally, signal network from EGFR to the signal‐related proteins was established using bioinformatic analysis. Interestingly, 9 of the 14 signal‐related proteins could be included in a network together with EGFR through direct interaction or only one intermediate partner. The signal cascade from EGFR to heat shock protein 27 (HSP27) and mitofilin (IMMT, inner membrane mitochondrial protein) might be the most important cascade. The signal network was certified by measuring the binding affinity of SB to EGFR in vitro, the effect of SB on internalization and phosphorylation of EGFR, the effect of SB on viability and proliferation of H9C2 cells, and the expression of inner membrane mitochondrial protein in the presence of EGFR inhibitor AG 1478.
Proteomic profiling of birch (Betula verrucosa) pollen extracts from different origins
Authors: Erler Anja , Hawranek Thomas , Krückemeier Leif , Asam Claudia , Egger Matthias , Ferreira Fátima , Briza Peter
Published: February 2011

Pollen of the European white birch is a major source of spring pollinosis in Europe. Pollen‐allergy diagnosis and treatment by specific immunotherapy commonly rely on extracts of natural origin. To gain insight into the protein content and its variability, we evaluated the profile of allergenic and non‐allergenic proteins in extracts of pollen from different origins by MS‐based proteomics. Aqueous extracts prepared from commercially available Swedish birch pollen, pollen collected from Austrian trees and a commercial skin prick extract were analyzed by 1‐DE, 2‐DE, immunoblotting and mass spectrometry, resulting in a complete inventory of extractable, disease‐relevant pollen proteins. A main focus of this study was on the isoform distribution of Bet v 1, the major allergen of birch pollen. Using a combination of intact mass determination and peptide sequencing, five isoforms (a, b, d, f and j) were unequivocally identified in Swedish and Austrian birch pollen extracts, while the skin prick extract contained only isoforms a, b and d. Using the same methods as for Bet v 1, divergencies in the sequence of birch profilin (Bet v 2), a plant panallergen, were solved. The molecular characterization of pollen extracts is relevant for standardization and development of new reagents for specific immunotherapy.
2‐D gel electrophoresis‐based proteomic analysis reveals that ormeloxifen induces G0–G1 growth arrest and ERK‐mediated apoptosis in chronic myeloid leukemia cells K562
Authors: Pal Pooja , Kanaujiya Jitendra K. , Lochab Savita , Tripathi Shashi B. , Bhatt Madan L. B. , Singh Pradhyumna K. , Sanyal Sabyasachi , Trivedi Arun K.
Published: February 2011

Ormeloxifen is a nonsteroidal selective estrogen receptor modulator (SERM) and has been shown to possess anticancer activities in breast and uterine cancer. Here, we show that ormeloxifen induces apoptosis in dose‐dependent manner in a variety of leukemia cells, more strikingly in K562. 2‐DE‐gel electrophoresis of K562 cells induced with ormeloxifen showed that 57 and 30% of proteins belong to apoptosis and cell‐cycle pathways, respectively. Our data demonstrate that ormeloxifen‐induced apoptosis in K562 cells involves activation of extracellular signal‐regulated kinases (ERKs) and subsequent cytochrome c release, leading to mitochondria‐mediated caspase‐3 activation. Ormeloxifen‐induced apoptosis via ERK activation was drastically inhibited by prior treatment of K562 cells with ERK inhibitor PD98059. Ormeloxifen also inhibits proliferation of K562 cells by blocking them in G0–G1 phase by inhibiting c‐myc promoter via ormeloxifen‐induced MBP‐1 (c‐myc promoter‐binding protein) and upregulation of p21 expression. We further show that ormeloxifen‐induced apoptosis in K562 is translatable to mononuclear cells isolated from chronic myeloid leukemia (CML) patients. Thus, ormeloxifen induces apoptosis in K562 cells via phosphorylation of ERK and arrests them in G0–G1 phase by reciprocal regulation of p21 and c‐myc. Therefore, inclusion of ormeloxifen in the therapy of chronic myeloid leukemia can be of potential utility.
Characterization of Dielectric Barrier Discharge (DBD) on Mouse and Histological Evaluation of the Plasma‐Treated Tissue
Authors: Rajasekaran Priyadarshini , Opländer Christian , Hoffmeister Dennis , Bibinov Nikita , Suschek Christoph Viktor , Wandke Dirk , Awakowicz Peter
Published: February 2011

Atmospheric‐pressure dielectric barrier discharge (DBD) in air is investigated for medical applications, especially for skin treatment. When the DBD was tested on mouse skin, a homogeneous discharge accompanied by filamentary microdischarges is observed. For characterization of the homogeneous discharge, averaged plasma parameters (namely electron density and electron velocity distribution function) and gas temperature are determined by optical emission spectroscopy, microphotography and numerical simulation. Chemical kinetics in the active plasma volume and in the afterglow is simulated. Fluxes of biologically useful molecules like nitric oxide (NO) and ozone reaching the treated surface and irradiation by UV photons are determined. Skin biopsy results show that DBD treatment causes no inflammation and no changes in the skin‐collagen.

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Assembly of Standardized Test Specimen for Microbial Quantification of Plasma Sterilization Processes of Fine PTFE Tubes as Used in Thermo Sensitive Medical Devices Like Flexible Endoscopes
Authors: Maucher Tanja , Schnabel Uta , Volkwein Wolfram , Köhnlein Johanna , Winter Jörn , Weltmann Klaus‐Dieter , Trick Iris , Oehr Christian
Published: February 2011

Fine PTFE tubes are used in high‐end and high cost devices like flexible Endoscopes where no standard sterilization procedure like autoclaving applies due to material properties. The study of innovative decontamination processes like plasma sterilization request appropriate analysis methods in order to verify the process functionality. In a related research project the IGB‐cycle‐method for contamination and recovery of indicator organisms like Bacillus atrophaeus spores was developed. It was possible to proof the IGB‐cycle‐method to be reproducible and reliable using round robin tests between three laboratories that compared their results in reference to a relevant level of contamination and recovery. Of a relevant contamination more than 7 log10 steps of cfu/specimen could be recovered from the tube surface.

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TGF‐β1‐induced EMT of non‐transformed prostate hyperplasia cells is characterized by early induction of SNAI2/Slug
Authors: Slabáková Eva , Pernicová Zuzana , Slavíčková Eva , Staršíchová Andrea , Kozubík Alois , Souček Karel
Published: February 2011

BACKGROUND

Epithelial–mesenchymal transition (EMT) underlying cancer cell invasion and metastasis has been thoroughly studied in prostate cancer. Although EMT markers have been clinically observed in benign prostate hyperplasia, molecular events underlying the onset and progression of EMT in benign prostate cells have not been described.

METHODS

EMT in BPH‐1 cells was induced by TGF‐β1 treatment and the kinetics of expression of EMT markers, regulators, and selected miRNAs was assessed by western blotting and quantitative RT‐PCR.

RESULTS

EMT in BPH‐1 cells was accompanied by rapid up‐regulation of SNAI2/Slug and ZEB1 transcription factors, while changes in expression levels of ZEB2 and miR‐200 family members were observed after extended time intervals. Invasive phenotype with EMT hallmarks, characterizing tumorigenic clones derived from BPH‐1 cells, was associated with increased mRNA levels of SNAI2, ZEB1, and ZEB2, but was not associated with significant changes in basal levels of miR‐200 family members. RNA interference revealed that SNAI2/Slug is crucial for TGF‐β1‐induced vimentin up‐regulation and migration of BPH‐1 cells.

CONCLUSIONS

This study suggests that in BPH‐1 cells the transcription factor SNAI2/Slug is important for EMT initiation, while the ZEB family of transcription factors in cooperation with the miR‐200 family may oppose the reversal of the EMT phenotype. Prostate 71:1332–1343, 2011. © 2011 Wiley‐Liss, Inc.
Prostate tumor cells with cancer progenitor properties have high telomerase activity and are rapidly killed by telomerase interference
Authors: Xu Tong , He Kaijie , Wang Lina , Goldkorn Amir
Published: February 2011

BACKGROUND

Cancer progenitor cells (CPCs) have been postulated to promote treatment resistance and disease progression in prostate and other malignancies. We investigated whether the enzyme telomerase, which is active in cancer cells and in normal stem cells, plays an important role in CPC which can be exploited to neutralize these cells.

METHODS

We used flow cytometry and assays of gene expression, clonogenicity, and invasiveness to isolate and characterize a putative CPC subpopulation from freshly resected human prostatectomy specimens. Telomerase activity was measured by qPCR‐based Telomeric Repeat Amplification Protocol (TRAP). Telomerase interference was achieved by ectopic expression of a mutated telomerase RNA construct which reprograms telomerase to generate “toxic” uncapped telomeres. Treated cells were assayed for apoptosis, proliferation in culture, and xenograft tumor formation.

RESULTS

CPC in prostate tumors expressed elevated levels of genes associated with a progenitor phenotype and were highly clonogenic and invasive. Significantly, CPC telomerase activity was 20‐ to 200‐fold higher than in non‐CPC from the same tumors, and CPC were exquisitely sensitive to telomerase interference which induced rapid apoptosis and growth inhibition. Similarly, induction of telomerase interference in highly tumorigenic CPC isolated from a prostate cancer cell line abrogated their ability to form tumor xenografts.

CONCLUSIONS

Human prostate tumors contain a CPC subpopulation with markedly elevated telomerase activity which renders them acutely susceptible to telomerase interference. These findings offer the first tumor‐derived and in vivo evidence that telomerase may constitute a CPC “Achilles heel” which may ultimately form the basis for more effective new CPC‐targeting therapies. Prostate 71:1390–1400, 2011. © 2011 Wiley‐Liss, Inc.
Antiandrogenic and growth inhibitory effects of ring‐substituted analogs of 3,3′‐diindolylmethane (Ring‐DIMs) in hormone‐responsive LNCaP human prostate cancer cells
Authors: Abdelbaqi Khalil , Lack Nathan , Guns Emma Tomlinson , Kotha Leela , Safe Stephen , Sanderson J. Thomas
Published: February 2011

BACKGROUND

Cruciferous vegetables protect against prostate cancer. Indole‐3‐carbinol (I3C) and its major metabolite 3,3′‐diindolylmethane (DIM), exhibit antitumor activities in vitro and in vivo. Several synthetic ring‐substituted dihaloDIMs (ring‐DIMs) appear to have increased anticancer activity.

METHODS

Inhibition of LNCaP prostate cancer cell growth was measured by a WST‐1 cell viability assay. Cytoplasmic and nuclear proteins were analyzed by immunoblotting and immunofluorescence. Androgen receptor (AR) activation was assessed by measuring prostate‐specific antigen (PSA) expression and using LNCaP cells containing human AR and an AR‐dependent probasin promoter‐green fluorescent protein (GFP) construct.

RESULTS

Like DIM, several ring‐substituted dihaloDIM analogs, namely 4,4′‐dibromo‐, 4,4′‐dichloro‐, 7,7′‐dibromo‐, and 7,7′‐dichloroDIM, significantly inhibited DHT‐stimulated growth of LNCaP cells at concentrations ≥1 µM. We observed structure‐dependent differences for the effects of the ring‐DIMs on AR expression, nuclear AR accumulation and PSA levels in LNCaP cells after 24 hr. Both 4,4′‐ and 7,7′‐dibromoDIM decreased AR protein and mRNA levels, whereas 4,4′‐ and 7,7′‐dichloroDIM had minimal effect. All four dihaloDIMs (10 and 30 µM) significantly decreased PSA protein and mRNA levels. Immuofluorescence studies showed that only the dibromoDIMs increased nuclear localization of AR. All ring‐DIMs caused a concentration‐dependent decrease in fluorescence induced by the synthetic androgen R1881 in LNCaP cells transfected with wild‐type human AR and an androgen‐responsive probasin promoter‐GFP gene construct, with potencies up to 10‐fold greater than that of DIM.

CONCLUSION

The antiandrogenic effects of ring‐DIMs suggest they may form the basis for the development of novel agents against hormone‐sensitive prostate cancer, alone or in combination with other drugs. Prostate 71:1401–1412, 2011. © 2011 Wiley‐Liss, Inc.
The expression of tousled kinases in CaP cell lines and its relation to radiation response and DSB repair
Authors: Ronald Sharon , Sunavala‐Dossabhoy Gulshan , Adams Lisa , Williams Briana , De Benedetti Arrigo
Published: February 2011

BACKGROUND

The Tousled‐like kinases (TLKs) function in processes of chromatin assembly, including replication, transcription, repair, and chromosome segregation. TLK1/1B interacts specifically with the chromatin assembly factor Asf1, a histone H3‐H4 chaperone, and with Rad9, a protein involved in DNA repair, and these interactions are believed to be responsible for the action of TLKs in double‐strand break repair and radioprotection.

METHODS

Western blotting and RT‐PCR were used to analyze the expression of TLK1, TLK1B, and TLK2 in a panel of prostate cancer (CaP) cell lines. The pattern of radiotolerance in the cell lines was analyzed in parallel. DU145 and PC‐3 cells were also probed with assays utilizing transfected plasmids that could be cleaved in vivo with adeno‐expressed HO nuclease to assess the potential contribution of TLK1/1B in DSB repair.

RESULTS

This is the first report of TLKs' expression in a panel of CaP cell lines and their relationship to radioresistance. Furthermore, expression of TLK1B in non‐expressing PC‐3 cells rendered them highly resistant to radiation, and conversely, knockdown to TLK1/1B in expressing DU145 reduced their radiotolerance.

CONCLUSIONS

TLKs appear to be intimately linked to the pattern of resistance to DNA damage, and specifically DSBs, a finding that was not reported before for any cell lines, and certainly not systematically for human prostate cell lines. Prostate 71:1367–1373, 2011. © 2011 Wiley‐Liss, Inc.
Blockade of transforming growth factor‐beta (TGFβ) signaling inhibits osteoblastic tumorigenesis by a novel human prostate cancer cell line
Authors: Mishra Sweta , Tang Yuping , Wang Long , deGraffenried Linda , Yeh I‐Tien , Werner Sherry , Troyer Dean , Copland John A. , Sun Lu‐Zhe
Published: February 2011

BACKGROUND

The skeleton is the most common site of prostate cancer metastasis, which often results in osteoblastic lesions. The role of transforming growth factor‐beta (TGFβ) signaling in prostate cancer‐induced osteoblastic metastasis is not clear. We investigated the role of TGFβ signaling in prostate cancer‐induced bone metastasis using a novel human prostate cancer cell line, PacMetUT1.

METHODS

We injected PacMetUT1/Luc‐GFP cells in male nude mice by intracardiac and intratibia injections and then investigated the effect of TGFβ signaling abrogation on osteoblastic tumor growth and incidence in vivo by using fluorescence and bioluminescence imaging analysis and quantifying bone and tumor volume by histomorphometry analysis. Osteoclasts were counted using TRAP assay.

RESULTS

Osteoblastic bone metastasis in skull, rib, and femur was detected after 10–16 weeks of intracardiac injection of the PacMetUT1 cells. Stable knockdown of TGFβ1 with an shRNA resulted in decreased tumor incidence and bone formation when the cells were directly injected into the tibiae. Systemic administration of either a small inhibitor of TGFβ type I receptor kinase or a pan TGFβ binding protein (BGERII) also decreased bone tumor growth and osteoblastic bone formation in vivo after 7 weeks of treatment.

CONCLUSIONS

Our results for the first time indicate that blockade of TGFβ signaling in the PacMetUT1 model significantly inhibits osteoblastic bone formation and tumor incidence. Thus, TGFβ signaling pathway may be a viable target for the prevention and treatment of prostate cancer‐induced bone metastasis. Prostate 71:1441–1454, 2011. © 2011 Wiley‐Liss, Inc.
Androgen receptor and heterogeneous nuclear ribonucleoprotein K colocalize in the nucleoplasm and are modulated by bicalutamide and 4‐hydroxy‐tamoxifen in prostatic cancer cell lines
Authors: Barboro Paola , Repaci Erica , Ferrari Nicoletta , Rubagotti Alessandra , Boccardo Francesco , Balbi Cecilia
Published: February 2011

BACKGROUND

Bicalutamide (BIC) is widely used in prostate cancer therapy. The dose and schedule employed are well tolerated, but about 50% of patients develop gynecomastia. Several studies have shown a significant reduction of the troublesome effects when Tamoxifen is concomitantly administered with BIC. However, the results reported in the literature seem to be preliminary and possible interferences could be present. In order to clarify the molecular mechanisms of the combination of the two drugs, we have investigated whether the expression of the proteins belonging to nuclear matrix (NM), one modulator of hormone action, is altered by BIC and/or 4‐hydroxy‐tamoxifen (4OHT) in LNCaP cells. We focused above all on heterogeneous nuclear ribonucleoprotein K (hnRNP K) a NM protein with a key role in prostate carcinoma.

METHODS

NM proteins were analyzed by two‐dimensional gel electrophoresis. Modulation and compartmentalization of the androgen receptor and the hnRNP K were studied by Western blotting, confocal microscopy, and immunoprecipitation.

RESULTS

Proteomic analysis revealed that there is a similarity in the changes of the NM proteins elicited by drugs alone but that their combination does not result in a simple additive effect. Moreover, we found that in the nucleoplasm the androgen receptor and the hnRNP K colocalize in a complex that is highly proximal to DNA and that both proteins were synchronously modulated by BIC and/or 4OHT treatment.

CONCLUSION

This study confirm the pivotal role of hnRNP K in prostate carcinoma and suggest that this role might be played by the interaction with the androgen receptor. Prostate 71:1466–1479, 2011. © 2011 Wiley‐Liss, Inc.