bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining the mechanical properties of epoxy resin (DGEBA) composites by ultrasonic velocity measurement
Authors: Oral Imran , Guzel Hatice , Ahmetli Gulnare 
Published: May 2012

AbstractIn this study, the composites of diglycidyl ether of bisphenol A (DGEBA) epoxy resin that have been formed by mixing epoxy resin with allyl glycidyl ether (AGE) and 2,3‐epoxypropyl methacrylate [glycidyl methacrylate (GMA)] were prepared in weight % ratios of 90 : 10, 80 : 20, and 70 : 30. A computer controlled analyzer with 35 MHz and a digital oscilloscope with 60 MHz were used for measuring the velocities of ultrasonic wave. The measurement of ultrasonic velocity carried out by pulse echo method at frequencies of 2.25 and 3.5 MHz at room temperature. The values of acoustic impedance (Z), Poisson ratio (μ), and coefficients of elasticity (L, G, K, E) of composites were calculated by values of densities and velocities that obtained. Thus, the effect of modificating epoxy resin (DGEBA) by AGE and GMA on mechanical properties of DGEBA was investigated using the ultrasonic method. Atomic force microscopy has been used for determining the microstructure of composites. By the results obtained from the investigation, it have been established that the longitudinal and shear ultrasonic wave velocities, and the values of all the elasticity constants of DGEBA were increased by modification with AGE and GMA. Also the most suitable combination ratio for the compound of DGEBA : AGE and DGEBA : GMA has been found as 80 : 20. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of nanosilica ball—PMMA hybrid composites
Authors: Kim Heon Chang , Noh Seung Man , Park Seung‐Kyu 
Published: May 2012

AbstractOrganic–inorganic hybrid materials are one of the most attractive topics, which deals from fundamental researches to practical applications. In the present research, we have studied the polymerization of methyl methacrylate (MMA) on the surface of γ‐methacryloxy propyl trimethoxy silane (γ‐MPS) modified nanosilica ball (NSB). The polymeric materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and thermo gravimetric analysis (TGA). The results show that new core‐shell structured materials, NSB core‐PMMA shell composites, have been synthesized. The core‐shell hybrid materials can be adjusted to form only a single spherical phase. The addition of the core‐shell hybrid materials to the clearcoat enhances the surface hardness and antiscratch property. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Thermal conductivity of poly vinylidene fluoride composites filled with expanded graphite and carbon nanotubes
Authors: Shou Qing‐Liang , Cheng Ji‐Peng , Fang Ji‐Hong , Lu Fei‐Hong , Zhao Jia‐Jie , Tao Xin‐Yong , Liu Fu , Zhang Xiao‐Bin 
Published: May 2012

AbstractThe composites composed of Poly (vinylidene fluoride), expanded graphite (EG), and carbon nanotubes (CNTs) have been prepared by solution mixing, followed by compression. The structure of the composites was examined with scanning electron microscope and their electrical and thermal properties were investigated. About 1.2 wt % content of CNTs could present a percolated network in the polymer matrix, characterized by the electrical conductivity. The incorporation of EG and CNTs in the polymer caused an enhancement in thermal conductivity for the composites. However, a hybrid of EG and CNTs as filler of the polymer yielded a further improvement in thermal conductivity as compared to single component filler. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Bifunctional initiators on the polymerization of vinyl acetate
Authors: Galhardo Eduardo , Franco Cilene Meinberg , Lona Liliane M. F. 
Published: May 2012

AbstractInitiators with functionality bigger than one can be used in free radical polymerization (FRP) to increase the polymerization rate without decreasing the molecular weight of the polymer. The use of bifunctional initiators to produce linear polymers (like polystyrene and Poly(methyl methacrylate) (PMMA)) can be found in the literature; however, their application to produce branched polymers is rarer. This work reports the effect of the bifunctional initiator Luperox 531 (1.4‐bi(t‐butyl‐carboperoxide) cyclehexane) on the FRP of vinyl acetate, which produces branched polymers. The monofunctional initiator Luperox TBEC (tert‐butylperoxide‐2‐etyhexil carbonate) is also used as base of comparison. Polymerizations in ampoules have been performed in different temperatures and initiator concentrations. Results were compared to those obtained from the styrene polymerization, which produces linear chains. It can be concluded that the effect of bifunctional initiators on FRP depends strongly on the kinetic mechanism, kind of monomer, and operating conditions adopted. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
CC Cross‐Coupling Reactions of O6‐Alkyl‐2‐Haloinosine Derivatives and a One‐Pot Cross‐Coupling/O6‐Deprotection Procedure
Authors: Gurram Venkateshwarlu , Pottabathini Narender , Garlapati Ramesh , Chaudhary Avinash B. , Patro Balaram , Lakshman Mahesh K. 
Published: May 2012

AbstractReaction conditions for the CC cross‐coupling of O6‐alkyl‐2‐bromo‐ and 2‐chloroinosine derivatives with aryl‐, hetaryl‐, and alkylboronic acids were studied. Optimization experiments with silyl‐protected 2‐bromo‐O6‐methylinosine led to the identification of [PdCl2(dcpf)]/K3PO4 in 1,4‐dioxane as the best conditions for these reactions (dcpf=1,1′‐bis(dicyclohexylphosphino)ferrocene). Attempted O6‐demethylation, as well as the replacement of the C‐6 methoxy group by amines, was unsuccessful, which led to the consideration of Pd‐cleavable groups such that CC cross‐coupling and O6‐deprotection could be accomplished in a single step. Thus, inosine 2‐chloro‐O6‐allylinosine was chosen as the substrate and, after re‐evaluation of the cross‐coupling conditions with 2‐chloro‐O6‐methylinosine as a model substrate, one‐step CC cross‐coupling/deprotection reactions were performed with the O6‐allyl analogue. These reactions are the first such examples of a one‐pot procedure for the modification and deprotection of purine nucleosides under CC cross‐coupling conditions.
Robust Exponential Stability of Discrete‐Time Delay Impulsive Systems with Parametric Uncertainties
Authors: Zhang Yu 
Published: May 2012

AbstractThis paper investigates robust exponential stability for discrete‐time delay impulsive systems with parametric uncertainties. The parametric uncertainties in the systems are assumed to be time varying and norm bounded. Using Lyapunov functionals, some robust exponential stability criteria are given. It is shown that the time interval between the nearest two impulses should be small enough, i.e., impulses must act frequently, when the impulses are employed to stabilize the original impulse‐free system that is not robustly stable. Conversely, when the original system without impulses is robustly stable, the time interval between the nearest two impulses should be large enough to let the system with impulsive perturbations retain its stability property. It should be noted that this is the first time that impulsive robust exponential stabilization results are given via Lyapunov functionals for discrete‐time uncertain delay impulsive systems. Some examples, including an example which cannot be studied by the existing results, are also presented to illustrate the effectiveness of the obtained results.
Passivity Analysis and Synthesis for a Class of Discrete‐Time Switched Stochastic Systems with Time‐Varying Delay
Authors: Lian Jie , Feng Zhi 
Published: May 2012

AbstractThis paper deals with the problems of passivity and passification for a class of discrete‐time switched stochastic systems with time‐varying delay. Based on the average dwell time approach, the piecewise Lyapunov function technique, and the free‐weighting matrix method, a new Lyapunov functional is proposed and sufficient conditions for mean‐square exponential stability and stochastic passivity are developed under average dwell time switching. Moreover, an estimate of state decay can be calculated in terms of linear matrix inequalities (LMIs). Then, the solvability condition for passification is established and the corresponding controller is designed. Two numerical examples are given to show the effectiveness of the proposed methods.
Decentralized Dynamic Coverage Control for Mobile Sensor Networks in a Non‐convex Environment
Authors: Song Cheng , Feng Gang , Wang Yong 
Published: May 2012

AbstractIn this paper, we consider the problem of decentralized dynamic coverage control for mobile sensor networks in an environment with unknown obstacles. The goal is to cover each point in the mission domain but outside the obstacles to a desired level. Each agent is modeled as a point mass based on Newton's law. A decentralized control strategy is developed to accomplish the dynamic coverage task without collision with obstacles. Discrete update of the cooperative coverage is also considered to enhance the cooperation of the agents in the fleet. The collision avoidance and global convergence of the proposed control scheme are proved and illustrated via a simulation example.
Combined effect of prenatal solvent exposure and GSTT1 or GSTM1 polymorphisms in the risk of birth defects
Authors: Garlantézec Ronan , Chevrier Cécile , Coiffec Isabelle , Celebi Catherine , Cordier Sylvaine 
Published: May 2012

AbstractExposure to solvents during pregnancy has long been suspected to increase the risk of congenital malformations. Glutathione S‐transferases (GSTs) are enzymes essential for the detoxification of various chemicals. Our objective here was to assess whether GST polymorphisms might modify the association between maternal solvent exposure and the risk of birth defects. A prospective cohort included 3421 pregnant women in Brittany, France (2002–2006). Occupational exposure to solvents was assessed from a job‐exposure matrix. Congenital malformations were diagnosed among livebirths, stillbirths, and medical pregnancy terminations. Using a nested case‐control design, 32 babies with major birth defects were compared to 348 normal births for babies' cord blood genotypes (at GSTT1 and GSTM1) and maternal occupational solvent exposure. Logistic models were used to adjust for potential confounders. The risk of major defects increased significantly in women with solvent exposure (20% of controls and 34% of cases). Frequencies of the null genotype of both the GSTT1 and GSTM1 genes were similar among controls and cases. There was a significantly increased risk of birth defects in GSTM1 not‐null cord‐blood genotype in pregnancies exposed to solvents (odds ratio [OR], 1.0 for not‐null, not‐exposed; OR, 4.0 for not‐null, exposed; 95% confidence interval [CI], 1.4–11.2; OR, 1.6 for null, not‐exposed; 95% CI, 0.6–3.9; OR, 1.0 for null, exposed; 95% CI, 0.2–4.7; p = 0.05). This nested case‐control study suggests that the child's GSTM1 genotype modifies the risk of major birth defects among offspring of solvent‐exposed women. Replication and additional investigations are necessary to confirm and elucidate these findings. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.
Peptoid–Peptide Hybrid Ligands Targeting the Polo Box Domain of Polo‐Like Kinase 1
Authors: Liu Fa , Park Jung‐Eun , Qian Wen‐Jian , Lim Dan , Scharow Andrej , Berg Thorsten , Yaffe Michael B. , Lee Kyung S. , Burke Terrence R. 
Published: May 2012

AbstractWe replaced the amino terminal Pro residue of the Plk1 polo‐box‐domain‐binding pentapeptide (PLHSpT) with a library of N‐alkyl‐Gly “peptoids”, and identified long‐chain tethered phenyl moieties giving greater than two‐orders‐of‐magnitude affinity enhancement. Further simplification by replacing the peptoid residue with appropriate amides gave low‐nanomolar affinity N‐acylated tetrapeptides. Binding of the N‐terminal long‐chain phenyl extension was demonstrated by X‐ray co‐crystal data.
Encapsulation of TCNQ and the Acridinium Ion within a Bisporphyrin Cavity: Synthesis, Structure, and Photophysical and HOMO–LUMO‐Gap‐Mediated Electron‐Transfer Properties
Authors: Chaudhary Arvind , Rath Sankar Prasad 
Published: May 2012

AbstractThe encapsulation of tetracyanoquinodimethane (TCNQ) and fluorescent probe acridinium ions (AcH+) by diethylpyrrole‐bridged bisporphyrin (H4DEP) was used to investigate the structural and spectroscopic changes within the bisporphyrin cavity upon substrate binding. X‐ray diffraction studies of the bisporphyrin host (H4DEP) and the encapsulated host–guest complexes (H4DEP⋅TCNQ and [H4DEP⋅AcH]ClO4) are reported. Negative and positive shifts of the reduction and oxidation potentials, respectively, indicated that it was difficult to reduce/oxidize the encapsulated complexes. The emission intensities of bisporphyrin, upon excitation at 560 nm, were quenched by about 65 % and 95 % in H4DEP⋅TCNQ and [H4DEP⋅AcH]ClO4, respectively, owing to photoinduced electron transfer from the excited state of the bisporphyrin to TCNQ/AcH+; this result was also supported by DFT calculations. Moreover, the fluorescence intensity of encapsulated AcH+ (excited at 340 nm) was also remarkably quenched compared to the free ions, owing to photoinduced singlet‐to‐singlet energy transfer from AcH+ to bisporphyrin. Thus, AcH+ acted as both an acceptor and a donor, depending on which part of the chromophore was excited in the host–guest complex. The electrochemically evaluated HOMO–LUMO gap was 0.71 and 1.42 eV in H4DEP⋅TCNQ and [H4DEP⋅AcH]ClO4, respectively, whilst the gap was 2.12 eV in H4DEP. The extremely low HOMO–LUMO gap in H4DEP⋅TCNQ led to facile electron transfer from the host to the guest, which was manifested in the lowering of the CN stretching frequency (in the solid state) in the IR spectra, a strong radical signal in the EPR spectra at 77 K, and also the presence of low‐energy bands in the UV/Vis spectra (in the solution phase). Such an efficient transfer was only possible when the donor and acceptor moieties were in close proximity to one another.
Enantioselectivity in degradation and transformation of quizalofop‐ethyl in soils
Authors: Li Zhaoyang , Li Qiaoling , Cheng Fengning , Zhang Wenshu , Wang Weixiao , Li Jingyin 
Published: May 2012

AbstractThe enantioselective degradation of quizalofop‐ethyl and its metabolite quizalofop‐acid in two soils, a Wuhan acidic soil and a Baoding alkaline soil, was investigated. The dissipation of quizalofop‐ethyl consisted of two phases, a rapidly deceasing first phase that lasted 1 day and a slowly decreasing second phase that extended till the end of the incubation. It is shown that S‐quizalofop‐ethyl degraded slightly faster than R‐quizalofop‐ethyl in the two soils. Further incubation of enantiopure enaniomers showed that quizalofop‐ethyl was configurationally stable in soil. Quizalofop‐acid was produced quickly, and its amount reached a maximum at 1–6 days time and then decreased slowly with half‐lives ranging from 11 to 21 days. The results also showed that quizalofop‐acid degraded faster in the acidic Wuhan soil than in the alkaline Baoding soil. At last, significant enantiomerization from S‐quizalofop‐acid to R‐quizalofop‐acid was observed, and the enantiomerization was fast, resulting in residues enriched with R‐quizalofop‐acid whatever racemic quizalofop‐ethyl or pure enantiomers were initially applied in the soils. Chirality 24:552–557, 2012. © 2012 Wiley Periodicals, Inc.
Clinical and proteomic characterization of acute myeloid leukemia with mutated RAS
Authors: Kadia Tapan M. , Kantarjian Hagop , Kornblau Steven , Borthakur Gautam , Faderl Stefan , Freireich Emil J. , Luthra Raja , Garcia‐Manero Guillermo , Pierce Sherry , Cortes Jorge , Ravandi Farhad 
Published: May 2012

AbstractBACKGROUND:Activating mutations in RAS are frequently present in patients with acute myeloid leukemia (AML), but their overall prognostic impact is not clear.METHODS:A retrospective analysis was performed to establish the clinical characteristics of patients with RAS‐mutated (RASmut) AML, to analyze their outcome by therapy, and to describe the proteomic profile of RASmut compared with wild‐type RAS (RASWT) AML.RESULTS:Of 609 patients with newly diagnosed AML, 11% had RASmut. Compared with RASWT, patients with RASmut AML were younger (median age, 54 years vs 63 years; P = .001), had a higher white blood cell count (16K mm−3 vs 4K mm−3 ; P < 0.001) and bone marrow blast percentage (56% vs 42%; P = .01) at diagnosis, and were less likely to have an antecedent hematologic disorder (36% vs 50%; P = .03). The inv(16) karyotype was overrepresented in patients with RASmut and the −5 and/or −7 karyotype was underrepresented. RAS mutations were found to have no prognostic impact on overall survival or disease‐free survival overall or within cytogenetic subgroups. There was a suggestion that patients with RASmut benefited from cytarabine (AraC)‐based therapy. Proteomic analysis revealed simultaneous upregulation of the RAS‐Raf‐MAP kinase and phosphoinositide 3‐kinase (PI3K) signaling pathways in patients with RASmut.CONCLUSIONS:RAS mutations in AML may delineate a subset of patients who benefit from AraC‐based therapy and who may be amenable to treatment with inhibitors of RAS and PI3K signaling pathways. Cancer 2012. © 2012 American Cancer Society.
Association of EGFR mutation or ALK rearrangement with expression of DNA repair and synthesis genes in never‐smoker women with pulmonary adenocarcinoma
Authors: Ren Shengxiang , Chen Xiaoxia , Kuang Peng , Zheng Limou , Su Chunxia , Li Jiayu , Li Bing , Wang Yongshen , Liu Lu , Hu Qiong , Zhang Jie , Tang Liang , Li Xuefei , Zhou Caicun , Schmid‐Bindert Gerald 
Published: May 2012

AbstractBACKGROUND:Epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) rearrangement may predict the outcome of targeted drug therapy and also are associated with the efficacy of chemotherapy in patients with nonsmall cell lung cancer (NSCLC). The authors of this report investigated the relation of EGFR mutation or ALK rearrangement status and the expression of DNA repair or synthesis genes, including excision repair cross‐complementing 1 (ERCC1), ribonucleotide reductase subunit M1 (RRM1), thymidylate synthetase (TS), and breast cancer‐early onset (BRCA1), as a potential explanation for these observations.METHODS:In total, 104 resected lung adenocarcinomas from women who were nonsmokers were analyzed concurrently for EGFR mutations, ALK rearrangements, and mRNA expression of the ERCC1, RRM1, TS, and BRCA1 genes. EGFR mutations were detected with a proprietary detection kit, ALK rearrangements were detected by polymerase chain reaction analysis, and genetic mRNA expression was detected by real‐time polymerase chain reaction analysis.RESULTS:Of 104 patients, 73 (70.2%) had EGFR mutations, and 10 (9.6%) had ALK rearrangements. ERCC1 mRNA levels in patients who had EGFR mutations were 3.44 ± 1.94 × 10−3, which were significantly lower than the levels in patients who were positive for ALK rearrangements and in patients who were negative for both biomarkers (4.60 ± 1.95 × 10−3 and 4.95 ± 2.33 × 10−3, respectively; P = .010). However, TS mRNA levels were significantly lower in patients who had EGFR mutations (1.15 ± 1.38 × 10−3 vs 2.69 ± 3.97 × 10−3; P = .006) or ALK rearrangements (1.21 ± 0.78 × 10−3 vs 2.69 ± 3.97 × 10−3; P = .020) than in patients who were negative for both biomarkers.CONCLUSIONS:NSCLC specimens that harbored activating EGFR mutations were more likely to express low ERCC1 and TS mRNA levels, whereas patients with NSCLC who had ALK rearrangement were more likely to express low TS mRNA levels. Cancer 2012. © 2012 American Cancer Society.
Interleukin‐13 receptor alpha2 is a novel therapeutic target for human adrenocortical carcinoma
Authors: Jain Meenu , Zhang Lisa , He Mei , Patterson Erin E. , Nilubol Naris , Fojo Antonio T. , Joshi Bharat , Puri Raj , Kebebew Electron 
Published: May 2012

AbstractBACKGROUND.Adrenocortical carcinoma (ACC) is a relatively rare but aggressive malignancy with limited therapeutic options. Previous genome‐wide expression studies have demonstrated the overexpression of interleukin‐13 receptor alpha2 (IL13Rα2) in some human malignancies.METHODS.The authors evaluated IL13Rα2 mRNA and protein expression in 21 normal samples, 78 benign samples, 10 primary malignant samples, and 25 metastatic/recurrent samples and performed functional analyses with IL13 ligand and IL13 Rα2 knockdown in vitro. The sensitivity of 2 ACC cell lines (NCI‐H295R [high IL13Rα2 expression] and SW13 [low IL13Rα2 expression]) to a highly specific IL‐13 conjugated with Pseudomonas exotoxin (IL‐13‐PE) also was evaluated in both in vitro and in vivo models.RESULTS.IL13Rα2 was overexpressed in malignant tumors compared with benign and normal samples (15‐fold higher; P < .05). Immunohistochemistry also confirmed higher protein expression in malignant and benign tumors than in normal adrenocortical tissues (P < .05). The half‐maximal inhibitory concentration for IL‐13‐PE was 1.3 ng/mL in the NCI‐H295R cell line and 1000 ng/mL in the SW13 cell line. Mice that received intratumoral or intraperitoneal IL‐13‐PE injection had a significant reduction in tumor size and increased tumor necrosis compared with control groups (P < .05) and also had prolonged survival (P < .05). IL13Rα2 protein expression increased in cells that were treated with IL‐13 ligand along with cell invasion (P < .05). Direct IL13Rα2 knockdown decreased cellular proliferation and invasion (P < .05).CONCLUSIONS.The current results indicated that IL13Rα2 is overexpressed in ACC and regulates cell invasion and proliferation. IL13Rα2 is a novel therapeutic target for the treatment of human ACC. Cancer 2012. © 2012 American Cancer Society.
Hilbert‐order based spatial cloaking algorithm in road network
Authors: Kim Yong‐Ki , Hossain Amina , Hossain Al‐Amin , Chang Jae‐Woo 
Published: May 2012

SUMMARYLocation‐based services (LBSs) are currently some of the fastest growing information technology industries. User privacy in LBSs has attracted great interest in the research community. However, the proliferation of position identifying devices has become an increasing privacy threat for users in LBSs. It is very difficult to avoid the privacy threat of a user in processing his/her request because the user has to submit his/her exact location with a query to the LBS. To protect privacy in road networks, the existing method employs an X‐Star framework to hide the query issuer and provide protection from attack resilience. However, it incurs low anonymization success rate and high computation cost. To solve the problems, we propose a Hilbert‐order‐based star network expansion cloaking algorithm (H‐Star). Our H‐Star guarantees k‐anonymity under the strict reciprocity condition and increases anonymization success rate by reducing computation overhead. We also propose k‐nearest neighbor and range query processing algorithms based on the anonymized region. Through comprehensive experimental analysis, we show the effectiveness of our algorithms in the field of spatial cloaking.Copyright © 2012 John Wiley & Sons, Ltd.