bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Substrate Temperature on the Al and Zr Co-Doped ZnO Thin Films Prepared by RF Magnetron Sputtering
Authors: Huan Fei , Leng Jin Feng , Meng Zhi Chao , Sun Bin , He Wen Shuang
Published: March 2015

ZnO doped Al2O3and ZrO2(ZAZO) thin films were deposited by the radio frequency magnetron sputtering on substrate temperature with 100°C, 150°C, 200°C, 250°C and 300°C. The surface morphology and electrical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and four-probe tester. The results showed that the substrate temperature obviously influenced the grain size of ZAZO films. The ZnO thin film had the largest crystallization orientation for the (002) peak and the smallest FWHM value at substrate temperature of 250°C. As the temperature increasing, the resistance of films gradually decreased till reaching a minimum at 250°C and then rised. Due to the increasing of Al and Zr concentrations into ZnO lattice, the Al ions created an abundance number of free electrons in the ZnO lattice, and in turn, the electrical conductivity increased. In addition, the improvement of film in the crystalline state results in the film resistivity decreases.
Characterization of Si/Artificial Graphite Composite Made by Mechanical Alloying for Li-Ion Cells
Authors: Guo Ya Nan , Jiang Xun Yong , Ang Ya Feng
Published: March 2015

Graphite is the widely used material as anode materials for Li-ion cells with a low theoretical capacity of 372 mAhg-1. Silicon has a high theoretical capacity of 4212 mAhg-1, but has a low intrinsic conductivity and its lower cycling life makes it unpractical. In this paper, silicon/artificial graphite composite was prepared by mechanical alloying to improve the cycle property of Si. On one hand, a new kind of alloy SiC was composited and composed as a coacervate, and the particle sizes of the silicon was reduced settled by mechanical alloying but the size of the new material become larger and larger with the proportion of artificial graphite increasing. On the other hand, the new material exhibits a better electrochemical performance, with the rate of its cyclic discharge capacity decreasing slowly.
Investigation of Chemical Vapor Deposited Graphene Film on Oxide Substrate
Authors: Huang Tao , Chen Lin , Sun Qing Qing , Zhou Peng , Zhang David Wei
Published: March 2015

Graphene is a novel two dimensional material with exceptional properties. Chemical vapor deposition of graphene on metal substrates is widely used to prepare high quality graphene film. However, the graphene films need to be transferred to oxide substrates for device applications. A chemical vapor deposition approach for direct growth of graphene films on zinc oxide was demonstrated in the present investigation. Raman spectra were used to characterize the grown graphene films. The impact of the growth temperature, time and gas flow ratio on the layer number and crystallite size of graphene was investigated.
Influence of Permeability and D33 on Fega/PZT/Fega Magnetoelectric Effect
Authors: Shi Jia Xing , Zhu Jie
Published: March 2015

FeGa/PZT/FeGa magnetoelectric device was prepared and the ME effect examined. FeGa alloys was made by different processing method. The results showed that the domains and texturing of FeGa had a great impact on both magnetic and ME performance. The permeability and d33(the differential of magnetostrictive coefficient) of FeGa differed with processing. It was found that FeGa rolled sheets had good toughness, d33could reach 2.7 ppm/Oe, and magnetic permeability reached 180 H/m. The device made of FeGa rolled sheets also had a large output (18 V/cm Oe) and low bias field (~ 96 Oe).
Disperse SiO2 Nanoparticles in Nonaqueous Solvents by Shear Emulsification and Surface Functionalization
Authors: Wang Chao , Li Xiao Yuan , Luo Qing , Ji Fang , Hu Su Rong , Wei Qi Long , Gao Wei , Huang Wen , Tang Guang Ping , He Jian Guo
Published: March 2015

Spheric SiO2 nanoparticles with the sizes distribution between 20-80 nm dispersed in nonaqueous solvent were prepared under the assistance of surfactant. Shear emulsification time was a key role for the dispersion of nanoparticles and the optimal value was 30 min with the smallest median size of 51 nm. The relationship between fluid viscosity and dispersion condition was researched, and the results demonstrated that the additional volume arising from aggregation interspaces enhanced shear fore and opposite resistance and finally the viscosity increased.
Effect of Thickness on Mechanically Tunable Magnetic Anisotropy of FeGa Thin Films Deposited on Flexible Substrates
Authors: Yu Ying , Xie Shu Hong , Zhan Qing Feng
Published: March 2015

A practical way to manipulate the magnetic anisotropy of magnetostrictive FeGa thin films grown on flexible polyethylene terephthalate (PET) substrates is introduced in this study. The effect of film thickness on magnetic properties and magnetostriction constant of polycrystalline FeGa thin films was investigated. The anisotropy field Hk of flexible FeGa films, i.e., the saturation field determined by fitting the hysteresis curves measured along the hard axis, was enhanced with increasing the tensile strain applied along the easy axis of the thin films, but this enhancement via strain became unconspicuous with increasing the thickness of FeGa films. In order to study the magnetic sensitivity of thin films responding to the external stress, we applied different strains on these films and measure the corresponding anisotropy field. Moreover, the effective magnetostriction constant of FeGa films was calculated from the changes of both anisotropy field and external strain based on the Villari effect. A Neel’s phenomenological model was developed to illustrate that the effective anisotropy field of FeGa thin films was contributed from both the constant volume term and the inverse thickness dependent surface term. Therefore, the magnetic properties for the volume and surface of FeGa thin films were different, which has been verified in this work by using vibrating sample magnetometer (VSM) and magneto-optic Kerr effect (MOKE) system. The anisotropy field contributed by the surface of FeGa film and obtained by MOKE is smaller than that contributed by the film volume and measured by VSM. We ascribed the difference in Hk to the relaxation of the effective strain applied on the films with increasing the thickness of films.
Effect of Surfactants on Morphology and Luminescent Properties of YAG:Ce Phosphors
Authors: Zhu Jia Ming , Wang Zhong Min , Tao Song , Peng Ying
Published: March 2015

Using anionic surfactant sodium dodecylsulfate (SDS), cationic surfactant cetyltrimethylammonium bromide (CTAB) and nonionic surfactant polyethylene glycol 20000 (PEG20000) and glyceryl monostearate (monostearin) respectively, Ce-doped Y3Al5O12(YAG:Ce3+(6%)) yellow phosphors were prepared by a combination method of high energy ball milling and solid state reaction. The effects of surfactant type on structure, morphology and luminescence properties were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and fluorescence spectrometer. The results showed that the crystal structure of YAG:Ce3+phosphors were not changed with the introduction of surfactants,but their morphology was greatly influenced. The maximum PL intensity was obtained for the nonionic surfactant PEG20000 due to the more uniform morphology and size as well as more homogeneous distribution of particles. Also, the results demonstrated that surfactant concentration had a vital effect on morphology and fluorescent properties of the phosphors,and the optimum amount of surfactant is 10 wt%.
Titanium Foams Prepared by Using Carbamide as Spacer for Cortical Bone Implant
Authors: Xiao Jian , Liao Yi Long , Qiu Gui Bao
Published: March 2015

Titanium (Ti) foams used in biomedical application has been attracted scientific and technological interest because of their excellent mechanical properties, superior corrosion resistance and good biocompability. In this article, Ti foam with semi-open cell was prepared using the acicular carbamide as a space holder without any adhesives. The pore structure was characterized by SEM and the mechanical properties were determined by compressive tests. The results show that the porosity is 56.8%, the compressive strength and Young’s modulus are 104.6 MPa and 2.9 GPa, respectively. These results demonstrated that the obtained foam has a great potential as a substitute biomaterial for cortical bone.
In Vitro Controlled Release of Topically Applied Capsaicin from Silk Hydrogel: A Study Contributed to the Pain Relief System
Authors: Jiang Rui , Zhang Fang , Yin Zhu Ping , Lu Shen Zhou
Published: March 2015

The availability of a safety and efficient vehicle for pain relief system remains major challenge. The clinical applications of capsaicin are restricted by lacking a long-term drug delivery system The purpose of the present study is to control the release of topically applied capsaicin from silk fibroin hydrogel, all factors including proportions of silk fibroin, amount of capsaicin and penetration enhancer are studied. The capsaicin release behavior was measured by using x-ray fluorescence spectroscopy (XRF). X-ray diffraction (XRD) was used to investigate structure of the silk fibroin hydrogels. The results indicate that the silk can protect the capsaicin and also all factors involved influence the capsaicin release behavior. The release of the capsaicin may be controlled exactly by changing the factors involved. So the silk fibroin hydrogels make the capsaicin a promising pain relief drug used in clinic in the future.
A New Type of Self-Aligned Technology for RF and Microwave Graphene Field-Effect Transistors
Authors: Wu Yong , Ma Zhong Fa , Du Lei , Zhang Peng , He Liang
Published: March 2015

A new type of fully self-aligned technology for graphene field-effect transistors was presented, in which a PVD SiO2 layer was taken as mask for the deposition of self-aligned source, drain and gate contacts. In this key process, the dielectric edge-sides exposure phenomenon during metal thermal evaporation was exploited. In the prepared self-aligned GFETs, both parasitic capacitance of the gate overlapped source and drain areas and series resistance of the spacing areas between gate and source and drain contacts were eliminated. The DC characterization and on-chip microwave measurement of the fabricated GFETs with channel length of 1give a maximum transconductanceof 2.32,field-effect mobilities of electrons and holes of 6924and 7035, and intrinsic cutoff frequencyof 0.5GHz, respectively, showing a significant improvement of both DC and RF performance.
Effects of Niobium Oxide Addition on the Mechanical Properties of Glass Ionomer Cement
Authors: Li Shi Qun , Su Bao Hui , Ran Jun Guo , Wang Jun , Yan Ling Ling , Tu Xiao Ming
Published: March 2015

Aiming at inadequate mechanical properties of Glass ionomer cement (GIC) commonly used in dental clinic, commercial and melt quenched GIC powders as control groups, homemade GIC powder was prepared by sol–gel route and modified by Nb2O5. The GIC samples were characterized by X-ray Diffraction (XRD), particle size analysis, Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FT-IR). The compressive strength, Vickers hardness, working and net setting time were tested. The data was analyzed by one-way ANOVA. The XRD results showed that commercial, melt quenched and sol gel GIC powders were similar amorphous. D90 of three GIC powders and Nb2O5 powder were 26 μm, 17 μm, 29 μm and 19 μm respectively. 5% Nb2O5-GIC exhibited the highest values of compressive strength and Vickers hardness, which were 112.93 Mpa, 139.48 MPa and 142.25 MPa respectively, increased 19.11%, 30.56% and 16.51% (P <0.05); the Vickers hardness were 35.15 MPa, 36.23 MPa and 37.62 MPa, increased 18.03%, 29.95% and 16.32% (P <0.05) compared to those of unmodified GICs as well. There was no significant change of the FT-IR characteristic peaks of modified GIC. The working time of three kinds of GIC were 4'58 ", 3'28" and 4'10 ", the net setting time were 5'16", 3'15 "and 4'38" (standard is 1.5-6 minutes). It was concluded that the dispersion stiffened effect of niobium oxide could improve the mechanical properties of the filling GIC without affecting the clinical operating performance.
Controlled Release of Growth Factors from Tissue Engineering Scaffolds Made by Positive and Negative Voltage Electrospinning
Authors: Zhao Qi Long , Zhou Yu , Wang Min
Published: March 2015

Emulsion electrospun nanofibrous tissue engineering scaffolds made by conventional positive voltage electrospinning (PVES) have various advantages for growth factor (GF) delivery. But problems such as high initial burst release still exist. Negative voltage electrospinning (NVES) may produce nanofiberous scaffolds that can modulate the release behavior of GFs which bear positive electrical charges. By using either PVES or NVES for emulsion electrospinng, the present study investigated the influence of NVES and applied voltage on the release behavior of a typical GF bearing the positive charge, basic fibroblast growth factor (bFGF), encapsulated in the nanofibers of poly (lactic-co-glycolic acid) (PLGA) scaffolds. Emulsions were firstly prepared by mixing a bFGF-containing aqueous solution and a PLGA solution. They were then subjected to electrospinning under either a positive voltage (10, 15, or 20 kV) or a negative voltage (-10, -15, or-20 kV). The morphology and structure of fibers and scaffolds were subsequently characterized. All scaffolds were nanofibrous and the nanofibers exhibited core-shell structures, with the bFGF-containing water phase forming the fiber core. Scaffolds exhibited the same type of electrical charges as the type of the applied voltage for electrospinning, i.e., scaffold made by PVES showed positive charges while scaffold fabricated by NVES possessed negative charges. The intensity of positive or negative charges borne by scaffolds and their retention time on scaffolds increased with an increase in the absolute value of the applied voltage (⏐V⏐). In vitro bFGF release experiments were conducted for scaffolds made by either NVES or PVES. Results showed that the bFGF release behavior was modulated by NVES.
Fabrication and Characteristics of Gene-Delivering Nanodevices Based on Au-Ag@CS-FA Hybrid Particles
Authors: Guan Qing Wen , Wang Min
Published: March 2015

Gene therapy has great potential in offering highly promising treatments for cancer. Polymer-metal hybrid nanoparticles (NPs) are good candidates as gene delivery vehicles due to their unique properties and facile functionalization. The polymer component in hybrid NPs can provide accurate cancer cell targeting and high DNA binding ability while the metallic component can provide imaging functions for the nanodevices. In the present study, hybrid NPs comprising an Au-Ag bimetallic core and a folic acid-chitosan shell (Au-Ag@CS-FA) were fabricated. The structure and relevant properties of Au-Ag@CS-FA NPs were subsequently studied using a variety of techniques,like scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM) and UV-visible spectra. Their DNA binding ability was also assessed. Results showed that Au-Ag@CS-FA NPs possessed properties that can make them excellent gene delivery vehicles.
Matrix Elasticity Affects Integrin Expression in Human Umbilical Cord-Derived Mesenchymal Stem Cells
Authors: Lv Hong Wei , Zhang Yin , Sun Mei Yu , Yang Jia Hui , Chen Zhi Shen , Fan Ming Ming , Li Li Sha , Li Yu Lin
Published: March 2015

Mesenchymal stem cells (MSCs) are a powerful cellular alternative for regenerative medicine and tissue engineering applications due to their multipotency. It is becoming increasingly clear that elasticity of extracellular matrix (ECM) has a profound effect on cell phenotype including adhesion, proliferation and differentiation. Integrins are considered to be important mechanoreceptors in mechanotransduction. While numerous studies have focused on α2, β1 and β3 integrin involvement in substrate stiffness-driven commitment of bone marrow MSCs, comparatively little is known about the change of α5β1 integrin expression in human umbilical cord-derived mesenchymal stem cells (hUCMSCs) on substrates of variable stiffness. We plated hUCMSCs on fibronectin coated polyacrylamide hydrogels with elasticity corresponding to Young’s modulus ranging from 3 to 65 kPa. Our results showed that hUCMSCs displayed different morphologies on substrates of varying stiffness. Cells led to branched morphology similar to that of nerve cells when cultured on soft matrices, while cells became more spread and presented polygonal shapes on stiff substrates. Furthermore, hUCMSCs expressed α5 integrin both on soft substrates and stiff substrates, and the expression levels on the two substrates were similar. The total β1 integrin (including both active and inactive) was higher in hUCMSCs grown on the stiff substrate than that of grown on soft substrates, whereas the activated β1 integrin level on stiff substrates was distinctly lower than that of grown on soft substrates. In conclusion, α5β1 integrin expression in hUCMSCs is dependent on matrix elasticity. The results from this study will provide insight into the role of α5β1 integrin in matrix elasticity-regulated morphologies changes of stem cells and have implication for understanding the mechanism of physical induced lineage specification.
Electron Beam Annealing for Component Optimization in Si-Sb-Te Material
Authors: Cheng Yan , Song San Nian , Zhang Zhong Hua , Song Zhi Tang , Liu Bo , Feng Song Lin , Zhang Ze
Published: March 2015

Electron beam (EB) annealing was used to acquire a reasonable and stable component in Si-Sb-Te material. For Si2Sb2Te5phase change material, EB irradiation can induce phase separation and some regions have remained unchanged, which manifests as SixSb2Te3. The component of these steady areas was considered as reasonable in which Sb2Te3is a stable compound. The crystallized Si3.3Sb2Te3film after EB irradiation exhibited nanoscale grains with well-proportioned distribution and these grains were all with Sb2Te3structure surrounded by amorphous. This unique structure brings fast phase change speed which is at least 12 times more rapidly than Si2Sb2Te5material because it localizes atoms’ diffusion in a nanoarea during reversible phase transition process.
Effect of Sericin Concentration on the Growth and Morphology of Escherichi Coli
Authors: Xue Rui , Chen Bing Jie , Jin Xiao , Zhang Qing Song , Han Mei Ling , Liang Cong Cong
Published: March 2015

Silk sericin composed of 18 amino acids has been widely used in the fields of cosmetic additives, food, medicine and functional biomaterials because of good hydrophilicity and biocompatibility, making it great possibility in providing abundant nutrients for microbial growth. Sericin (40~200 KDa) was used as culture medium for incubation of E. coli at 37°C to study the effect of sericin concentration on the growth of bacterial Escherichi coli (E. coli). The growth curves of E. coli, surface/inside morphology and protein of E. coli were investigated by UV/vis spectrophotometer (UV/vis), scanning electron microscopy (SEM), transmission electronic microscopy (TEM) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The cytotoxicity of sercin was also confirmed by MTT assay. The value of OD600 increases with increasing sericin concentration from 0 to 40 g/L. Compared with the control, OD600 of 40 g/L sericin medium increases from 0.013 to 1.269 after incubated 12h. E. coli cell still remains rod shape regardless of concentration of sericin. The content of cellular soluble proteins significantly increases in sericin-treated bacteria, which in turn influenced the cell structure composition and catalyzing activity of enzyme, and finally stimulated the proliferation of E. coli. Results indicate that sericin can independently provide carbon and nitrogen for bacterial growth. Besides, it can promote bacterial protein expression without affecting cell morphology.
Synthesis and Characterization of Optical Active PLA Degradable Materials
Authors: Zhao Xi Po , Wu Tao , Lin Qiang , Jin Fei , Li Rong Zhe , Peng Shao Xian
Published: March 2015

An optical active Acrylate end-functionalized poly (lactic acid) (DPLA) was synthesized via melt polycondensation, with lactic acid, polyalcohol and acrylic acid as raw materials. The prepolymer products in each process were characterized by FT-IR, 1H-NMR. The curing PLA coating (CPLA) was prepared using optical active DPLA, reactive diluent and photoinitiator. Gel fraction, thermal stability and degradation properties of the UV curing PLA coating properties were evaluated. The results show that branched structure of hydroxyl-terminated poly (lactic acid) (OHPLA) is beneficial to increase acrylic end capping rate (Da), Da ois as high as 88%. The structure of prepolymer and the performance of the coating are adjusted by changing content of polyalcohol. After crosslinking modification, degradation rate of CPLA is reduced and CPLA has better thermal stability than the pure PLA.
Microwave Absorption Properties of Solid-State Polymerization Ethylenedioxythiophene
Authors: Xu Zhuang Hu , Sui Ming Xu , Sun Meng Xiao , Wang Yuan , Wang Ming Yang
Published: March 2015

Poly (3,4-ethylenedioxythiophene) (PEDOT) has been synthesized through a facile solid-state polymerization (SSP) approach. The polymerization was simply initiated by sintering the monomer, 2,5-dibro-3,4-ethylenedioxythiophene (DBEDOT), at the temperature of 80 °C. The SSP-PEDOT with the heating time for 24 hours has the maximum value of dielectric loss tangent (tanδε) in the frequency range of 2-18 GHz, which revealed that this sample has the best electromagnetic energy absorption ability. When the thickness of the sample reached 2 mm, the bandwidth with the reflection loss (RL) deeper than −10 dB is nearly 5.9 GHz (From 10.0 GHz to 15.9 GHz), and the maximum value of RL is about −50.1 dB at 11.2 GHz. These results demonstrate that SSP initiated at low temperature shows multi-practical application in the areas of military camouflage, and electronic devices protection.
Mechanical and Thermomechanical Properties of Nylon6T/66/PPS Blends
Authors: Zhang Qi , Luo Xiao Lin , Zhang Mei Lin , Wang Xiao Jun , Zhang Gang , Long Sheng Ru , Yang Jie
Published: March 2015

Polymer blending is a very important and widely used method for the modification of polymer materials. However, little attention has been paid to the Semi-aromatic Polyamides with PPS blends. In this article, we investigate the properties of Poly (phenylene sulfide) (PPS) blends with Poly (hexamethylene terephthalamide/hexamethylene hexanediamide) (nylon 6T/66). The structure, mechanical properties of nylon 6T/66 and (PPS) blends were studied by scanning electron microscopy (SEM), Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TG). The results indicate that the blends have good thermal stability and the tensile strength, flexural strength and flexural modulus of the blends are better than the PA6T/66 but worse than that of the PPS.
Microstructure and Thermal Properties of PET/POSS Composites Prepared by In Situ Polymerization
Authors: Liu Wei , Wang Shu Xia , Dai Jun Ming , Li Guang
Published: March 2015

Poly(ethylene terephathalate)/1,2-propanediolisobutyl polyhedral oligomeric silsesquioxane (POSS) composites were prepared by in situ polymerization with 1.5-5.0 wt% loading of POSS. The dispersion of POSS in PET matrix was investigated by scanning electron microscope(SEM) the interaction between POSS and PET chains was studied by nuclear magnetic resonance(NMR) andX-ray photoelectron spectroscopy(XPS), and the thermal behavior of PET/POSS composites was investigated by DSC and TG as well as the melt rheological testing of PET/POSS. SEM observation suggests that POSS particles disperse evenly innanosize(80-100nm)in PET matrix, and this fine dispersion of POSS was further supported by XPS analysis, there is a covalent linkage presenting between POSS and PET chains. The crystallization temperature of the composites moved to high temperature as the POSS particles behave as the nucleating agent. The shear modulus(G’) increased apparently with the addition of POSS.
Surface Plasmon Enhanced Photoluminescence of the Rubrene Film by Silver Nanoparticles
Authors: Chen Liang , Deng Jin Xiang , Cui Min , Le Kong , Chen Ren Gang , Zhang Zi Jia
Published: March 2015

Silver nanoparticles (Ag NPs) thin film were fabricated by radio-frequency (RF) magnetron sputtering on the quartz substrates in different sputtering time, then covered with a layer of rubrene by means of thermal evaporation. The sputtering time for preparation of Ag NPs could be tuned to increase the spectral overlap between the emission spectra of rubrene and surface plasmon resonance spectra, so that the surface plasmon enhancement was improved. Using a Fluorescence spectrophotometer (FLS920), the photoluminescence (PL) intensity of the rubrene/Ag NPs thin film was up to 22 times higher than that as-deposited rubrene thin film. It is attributed to the energy transfer effect in the surface plasmon resonance coupling, the surface plasmons mediated emission, and light scattering.
Effect of Orotic Acid on the Stabilization Efficiency of Ca-Zn Thermal Stabilizers for Poly(vinyl chloride)
Authors: Xu Xiao Peng , Chen Si , Shi Yan Qin , Wu Bo Zhen , Ma Meng , Wang Xu
Published: March 2015

The effect of orotic acid (OA) and its mixtures with calcium stearate (CaSt2) and zinc stearate (ZnSt2) in various ratios on the thermal stability of PVC has been investigated by Congo red and discoloration tests. The results shows that OA acts as a long-term thermal stabilizer for PVC like CaSt2, and the combination of OA and ZnSt2 exhibited a synergistic stabilization effect at a certain ratio. This is due to the ability of OA to absorb HCl released during the degradation of PVC to diminish its catalytic effects, and react with ZnCl2 to stop its catalytic effect for PVC. CaSt2-ZnSt2/OA stabilizers exhibit good synergistic effects with both acceptable initial color and long-term stability for PVC
Crosslinking of Polyamide 6 by Reactive Processing
Authors: Yu Tao , Chen Jian Sheng , Wu Fu Mei , Rocks Jens
Published: March 2015

In order to check the feasibility of crosslinking engineering plastics through chemical coupling, reactive blending of polyamide 6 (PA6) was performed with various amounts of a multi-functional epoxide named as Joncryl ADR®4370s. The formation of cross-linked structure in ADR modified PA6 was clearly verified by utilizing dynamic rheological technique. The thermal properties of modified PA6 were compared with that of pristine nylon by combination of differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Mechanical tests were also carried out and the results showed that ADR had a positive effect on improving tensile properties of polyamide.
Tensile Strength of Surface Treated PBO Fiber
Authors: Shi Gang , Ju Su , Huang Chun Fang , Jiang Da Zhi , Zhang Jian Wei
Published: March 2015

Poly p-phenylene benzobisoxazole (PBO) fiber is a kind of organic fiber with high performance, but the properties of the interface between PBO fiber and resin are poor, which limit its application in the field of composite materials. Therefore, the surface modification methods were employed to enhance the interface properties, which could damage the fiber. This article assessed the influence of plasma modification, γ-ray irradiation, coupling agent, acid treatment and combined treatments on the strength of PBO fiber filament, and investigated its tensile strength with Weibull analysis. Through observation of fiber surface by SEM，it can be found that some combined treatments caused less damage to PBO fiber compared to the individual treatments. This indicates that if combining the different treatments appropriately, the interface energy of PBO fiber will increase, with the excellent mechanical properties well retained
Microstructure Evolution of PtTi0.5Zr0.2/Ti Laminated Composites Synthesized by Hot Pressing and Rolling
Authors: Fan Ye , Zhang Xiao Ge , Zhao Qiong , Qin Guo Yi , Xu Si Yong , Guo Jin Xin
Published: March 2015

The PtTi0.5Zr0.2/Ti laminated composite was prepared by hot pressing and rolling process. Microstructure, interlaminar spacing and mechanical property of the microlaminated composites after rolling were evaluated. The results showed that the layer structures of laminated composites remained consecutiveness with 93% deformation. The 12μm PtTi0.5Zr0.2 layer and 8μm Ti layer was observed finally, as well as the intermetallic compound Ti3Pt making the PtTi0.5Zr0.2 layer and Ti layer connect with each other. Compared with Platinum and Titanium, the tensile strength of PtTi0.5Zr0.2/Ti laminated composite was enhanced by approximately 59% and 29% respectively and reached 657MPa. The tensile fracture was more uniform and showed a more coordinated process.
Functionalization of Smart Gels with Beta-Cyclodextrin and Release Characteristics to Simulating Drugs
Authors: Gao Ming Jun , Wang Jia Li , Cong Qin , Zhang Bo , He Xiao Chun , Ma Xing Fa , Li Guang
Published: March 2015

Smart gels have many applications in sensors, actuators, shape memory intelligent devices, recognition, self-healing, drug release, biomimetic soft robot design, biomimetic tactile, neural regeneration, biomimetic membranes, supercapacitor, dye-sensitized solar cells, advanced lithium polymer batteries, environmental fields, biomedical fields, et al. And that cyclodextrins are one of the typical macrocycles with good recognition ability, and endowed with fascinating hydrophobic cavities and hydrophilic surface, which enable the encapsulation of diverse small organic molecules by forming inclusion complexes. In this paper, grafted copolymerization between acrylic acid and N,N-dimethyl acrylamide in the presence of water-soluble cyclodextrins was carried out. The effect of ratio of copolymerization monomer on the grafted polymer was examined. The results indicated that self-crosslinking smart gel with multi-stimuli responsive was obtained by selecting suitable the ratio of copolymerization monomer, its behaviors of swelling/shrinking were examined. The adsorption properties and releasing characteristics of smart gel were performed with simulating drugs. Some meaningful results were obtained. These series grafted copolymer would also be used to modify the surface and interface properties of low-dimensional functional materials or heterostructured nanocomposites for intelligent organic-inorganic functional nanocomposites, some good results were obtained.
An Organic Double-Layer Coating on Aluminum and Steel Substrates for Anti-Laser Protection
Authors: Guan Zhen Wei , Li Jing , Zhang Tong , Zhang Yu Zhong , Liu Peng Rui , Wang Zhi Yong
Published: March 2015

In this work, an organic double-layer protective coating (ODC) was fabricated through a simple spray process on aluminum and steel. The coating is built as double-layer structure of heat resist base layer and reflective surface layer. Laser with power 103~104Wcm-2was set to ablate samples for 4s, while the temperature of panels’ back were being measured. Also, reflectivity of the coating was tested. Results demonstrated that reflectivity of ODC was up to 94%, and the panels were less apt to be ablated by laser radiation after coated, while the temperatures measured were substantially lower compared to blank panels with respect to the coating structure and composition.
Occurrence and correlation between the numbers of Black-headed Gull Chroicocephalus ridibundus and Yellow-legged Gull Larus michahellis on Kolut fish ponds (Serbia)
Authors: Tucakov Marko , Vogrin Milan
Published: March 2015

Presence and correlation between the numbers of Black-headed and Yellow-legged Gull was studies between 1998 and 2004 on Kolut fishponds in NW Serbia. Both species occurred there from February to December. Spring migration culminated in late February and early March. The period of the most intensive autumn concentration was from October to December. The difference between the numbers in all months as well as between the numbers in spring and in autumn was statistically significant. The period of the most intensive autumn passage of Yellow-legged Gull was from late October to early December. The difference between the numbers between the months was not statistically significant. A high concentration of both species in autumn and early winter was explained by high food availability during fish harvest when ponds were empty. Positive correlation between the numbers of two species thru the year indicated attractiveness of large flocks of Black-headed Gulls for Yellow-legged Gulls. This is especially true for the autumn period, when feeding niches and food is easily accessible. Correlation between the numbers of two species was negative in spring, when accesibility of aquatic animals is lower and large flocks of Black-headed Gulls are lacking.
Editorial
Authors: Bogliani Giuseppe
Published: March 2015

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Responsiveness to acoustic stimulation, distribution and habitat preferences of the Grey-headed Woodpecker, Picus canus, and the Three-toed Woodpecker, Picoides tridactylus, in Friuli-Venezia Giulia (North-eastern Italy)
Authors: Rassati Gianluca
Published: March 2015

The study was carried out from 2003 to 2011 with the aim of determining the responsiveness to acoustic stimulation, the distribution and the habitat preferences of Picus canus and Picoides tridactylus in Friuli-Venezia Giulia (NE Italy). P. canus resulted as being more responsive than P. tridactylus to conspecifics stimulation, responding in 13.23% of the points where a stimulus was emitted, against 7.65% of the other species. In both taxa, when there was a response, it was predominantly by the male birds. The most frequent type of response in P. canus was song, heard in 57.89% of the points, while for P. tridactylus, it was drumming, which was heard in 65.38% of the points. For both species (especially for P. tridactylus), a tendency was recorded to expand the range and to occupy new areas within the known range. P. canus in Friuli-Venezia Giulia was found from altitudes close to the sea level up to the treeline (range 0-2000 m a.s.l.), while P. tridactylus was found in montane and subalpine woodlands (range 800- 2000 m a.s.l.). The observations of P. canus were obtained at a mean altitude of 977 m a.s.l. (± 402 SD), located in the altitudinal belt dominated by Fagus sylvatica L., which is present in more than half of the woodlands in which the woodpecker was found. P. tridactylus was discovered at a mean altitude of 1424 m a.s.l. (± 246 SD), located in the altitudinal belt dominated by Picea abies (L.) H. Karst., which is present in almost 90% of the woodlands in which this species was found. In some areas, densities of 0.67-2.26 territories/100 ha were obtained for P. canus and 0.16-0.40 territories/100 ha for P. tridactylus. In Friuli-Venezia Giulia, a population of 320-390 pairs of P. canus and 45-60 pairs of P. tridactylus has been estimated, with an approximate 15% increase of P. canus compared to the beginning of the century, and just over 60% for the other species. Finally, some aspects concerning conservation-related problems are reported.
Short Communications
Authors: Authors The
Published: March 2015

Overwintering of Crane, Grus grus, within the Alpine arch

Prima nidificazione accertata di assiolo Otus scops in provincia di Varese
Development and Validation of the Athlete Fear Avoidance Questionnaire
Authors: Dover Geoffrey , Amar Vanessa
Published: March 2015

Context

The fear-avoidance model was developed in an attempt to explain the process by which “pain experience” and “pain behavior” become dissociated from the actual pain sensation in individuals who manifest the phenomenon of exaggerated pain perception. High levels of fear avoidance can lead to chronic pain and disability and have successfully predicted rehabilitation time in the work-related–injury population. Existing fear-avoidance questionnaires have all been developed for the general population, but these questionnaires may not be specific enough to fully assess fear avoidance in an athletic population that copes with pain differently than the general population.

Objective

To develop and validate the Athlete Fear Avoidance Questionnaire (AFAQ).

Design

Qualitative research to develop the AFAQ and a cross-sectional study to validate the scale.

Patients or Other Participants

For questionnaire development, a total of 8 experts in the fields of athletic therapy, sport psychology, and fear avoidance were called upon to generate and rate items for the AFAQ. For determining concurrent validity, 99 varsity athletes from various sports participated.

Data Collection and Analysis

A total of 99 varsity athletes completed the AFAQ, the Fear-Avoidance Beliefs Questionnaire, and the Pain Catastrophizing Scale. We used Pearson correlations to establish concurrent validity.

Results

Concurrent validity was established with significant correlations between the AFAQ and the Fear Avoidance Beliefs Questionnaire-Physical Activity (r = 0.352, P > .001) as well as with the Pain Catastrophizing Scale (r = 0.587, P > .001). High internal consistency of our questionnaire was established with a Cronbach α coefficient of 0.805. The final version of the questionnaire includes 10 items with good internal validity (P < .05).

Conclusions

We developed a questionnaire with good internal and external validity. The AFAQ is a scale that measures sport-injury–related fear avoidance in athletes and could be used to identify potential psychological barriers to rehabilitation.
The relevance of human capital to firm performance: A focus on the retail industry in Kinshasa, Democratic Republic of Congo
Authors: Urban Boris , Kongo Michael
Published: March 2015

Purpose and problem: Human capital represents an investment in education and skills. However, in the Democratic Republic of Congo (DRC) the ability of small-scale retailers to grow and increase firm performance is restricted by the scarcity of education and prior work experience.Methodology: Survey data were collected from 126 owner-managers in the retail industry in Kinshasa, DRC, in order to investigate the proposed relationship between the human capital components of education, work experience and venture performance.Findings: Several variables pertaining to education and prior work experience were related to different aspects of venture performance, allowing for support of the hypotheses. Nonetheless, when clustering was conducted some surprising results were observed in that owner-managers tended to have little work experience even where their venture was performing well.Implications: Research into human capital and links to performance in Africa and emerging markets is valuable as recent research has found that the matching of entrepreneurial human capital with opportunities for growth is the essence of economic development.
Cracking the nut of service-learning in nursing at a higher educational institution
Authors: Julie Hester , Adejumo Oluyinka A. , Frantz Jose M.
Published: March 2015

Background: The readiness of academics to engage in the service-learning (SL) institutionalisation process is not accentuated in research on SL institutionalisation in South Africa. The argument has been advanced that SL scholarship and willingness of key stakeholders are crucial for SL institutionalisation at the academic programme level.Aim: The research focus of the study being reported here was on readiness of respondents to embed SL in the curricula of the nursing programme.Method: This study used a quantitative, exploratory and descriptive design. A self-administered structured questionnaire was used to collect data from a stratified sample comprising 34 respondents. The data were analysed for descriptive statistics using SPSS 19.Results: The demographic profile of the respondents indicated that 31 (66%) were between 31 and 50 years old; 36 (75.16%) had a minimum of 10 years’ nursing experience; 19 (39.6%) had a master’s degree, two (4.2%) had a doctorate; and 29 (60.4%) had been employed by the school for a maximum of five years. The results indicated that the nurse educators were in need of SL capacity-building because 9 (18.8%) had limited or no knowledge of SL and 24 (50%) confused SL with other forms of community engagement activities. However, only 15 (33%) of the clinical supervisors and 13 (27%) of the lecturers indicated a willingness to participate in such a programme.Conclusion: The school was not ready to embed SL in the academic programme because of a lack of SL scholarship and willingness to remediate the identified theory–practice gaps.
Three poems
Authors: Mann Chris M.
Published: March 2015

No abstract available.
A Propensity Score-Matching Analysis of Transthoracic Echocardiography and Abdominal Ultrasonography for the Detection of Abdominal Aortic Aneurysms
Authors: Kato Takao , Ishida Seiko , Miyamoto Shoichi , Iura Tamae , Ban Yoko , Fujikawa Jun , Nakane Eisaku , Izumi Toshiaki , Haruna Tetsuya , Ueyama Koji , Nohara Ryuji , Inoko Moriaki
Published: March 2015

Introduction

We previously reported that the prevalence of abdominal aortic aneurysms (AAAs) was higher in patients undergoing scheduled transthoracic echocardiography (TTE) than in patients undergoing abdominal ultrasonography (AUS); however, intergroup patient backgrounds differed significantly in that report.

Purpose

We tested the hypothesis that TTE could detect AAA as effectively as AUS.

Design

A propensity score-matching analysis of a cross-sectional study was adopted as the design for this study.

Methods

We enrolled 7,619 and 15,433 patients scheduled to undergo TTE with additional evaluation of abdominal aorta at the end of the routine study and AUS, respectively, from 2009 to 2010 in our hospital, as reported. A propensity score for profiles of patients who underwent TTE or AUS was developed to adjust for potential confounding bias. Consequently, 4,388 patients in each group were matched for analyses.

Results

In propensity-matched patients, AAA was detected in 59 patients of the TTE group and in 48 patients of the AUS group; the prevalence of AAA detection did not differ significantly between TTE and AUS groups ( P = 0.331). Positive associations were observed between AAA detection and male sex (adjusted odds ratio [OR]: 3.25; 95% confidence interval [CI], 2.05-5.15; P < 0.001), older age (adjusted OR: 1.029; 95% CI: 1.01-1.04; P < 0.001), and the presence of ischemic heart disease (adjusted OR: 1.78; 95% CI: 1.04-3.03; P = 0.033) and hypertension (adjusted OR: 2.16; 95% CI: 1.38-3.37; P = 001).

Conclusion

TTE detected AAA with comparable efficacy as AUS in propensity-matched groups who underwent scheduled TTE and AUS.
Influence of Occlusal Contact Area on Cusp Deflection and Stress Distribution
Authors: Costa Anna Karina Figueiredo , Xavier Thaty Aparecida , Paes-Junior Tarcisio José Arruda , Andreatta-Filho Oswaldo Daniel , Borges Alexandre Luiz Souto
Published: March 2015

Objective

The purpose of this study was to evaluate the effect of occlusal contact area for loading on the cuspal deflection and stress distribution in a first premolar restored with a high elastic modulus restorative material.

Materials and methods

The Rhinoceros 4.0 software was used for modeling the three-dimensional geometries of dental and periodontal structures and the inlay restoration. Thus, two different models, intact and restored teeth with three occlusal contact areas, 0.1, 0.5 and 0.75 mm2, on enamel at the occlusal surface of buccal and lingual cusps. Finite element analysis (FEA) was performed with the program ANSYS (Workbench 13.0), which generated a mesh with tetrahedral elements with greater refinement in the regions of interest, and was constrained at the bases of cortical and trabecular bone in all axis and loaded with 100 N normal to each contact area.

Results

To analysis of maximum principal stress, the smaller occlusal contact area showed greater compressive stress in region of load application for both the intact and inlay restored tooth. However, tensile stresses at the occlusal isthmus were similar for all three tested occlusal contact areas (60 MPa). To displacement of the cusps was higher for teeth with inlay (0.46- 0.48 mm). For intact teeth, the smaller contact area showed greater displacement (0.10 mm). For teeth with inlays, the displacement of the cusps were similar in all types of occlusal area.

Conclusion

Cuspal displacement was higher in the restored tooth when compared to the intact tooth, but there were no significant variations even with changes in the occlusal contact area.

Relevance clinical

Occlusal contacts have a great influence on the positioning of teeth being able to maintain the position and stability of the mandible. Axial loads would be able to generate more uniform stress at the root presenting a greater concentration of load application in the point and the occlusal surface. Thus, is necessary to analyze the relationship between these occlusal contacts as dental wear and subsequent occlusal interferences.

How to cite this article

Costa AKF, Xavier TA, Paes-Junior TJA, Andreatta-Filho OD, Borges ALS. Influence of Occlusal Contact Area on Cusp Deflection and Stress Distribution. J Contemp Dent Pract 2014;15(6):699-704.
Study of Pulp Chamber Morphology of Primary Mandibular Molars using Spiral Computed Tomography
Authors: Selvakumar Haridoss , Kavitha Swaminathan , Vijayakumar Rajendran , Eapen Thomas , Bharathan Rajendran
Published: March 2015

Aim

The purpose of this study was to evaluate the pulp chamber morphology in primary mandibular molars using spiral computed tomography (SCT).

Materials and methods

Sixty extracted primary mandibular molars were scanned using SCT for the (i) distance between the central fissure to furcation, (ii) distance between the central fissure to the floor of the pulp chamber, (iii) height of the pulp chamber (roof-floor), (iv) distance between the floor of the pulp chamber to the furcation. The mean and standard deviation was analyzed using statistical package for the social sciences (SPSS) program.

Results

The results of this study show that the average mean distance from the central fissure to the floor of the pulp chamber is 5.07 mm in first mandibular primary molar and 5.54 mm in second mandibular primary molar.

Conclusion

It can be concluded that the greatest depth to which a bur can go during access opening without perforating the furcation in first primary mandibular molar is 5.07 mm and 5.54 mm in second primary mandibular molar.

How to cite this article

Selvakumar H, Kavitha S, Vijayakumar R, Eapen T, Bharathan R. Study of Pulp Chamber Morphology of Primary Mandibular Molars using Spiral Computed Tomography. J Contemp Dent Pract 2014;15(6):726-729.