Ti-Zr alloys have gained increasing attention as a new metallic biomaterial, being used as implants for both orthopedics and dentistry. More recently, our group found promising results for the Ti-45Zr alloy, which presented a low elastic modulus, a pronounced and excellent mechanic character, and excellent cell compatibility in vitro. However, its biocompatibility and potential to promote osteogenesis in vivo remained unclear. In the present study, the biocompatibility, osteointegration ability, and immune response effects of the Ti-45Zr alloy were evaluated in animal experiments. The results showed that the alloy had good blood compatibility and no body side effects. After implantation in vivo, the inflammation turned out well and was beneficial to the polarization of macrophages. Additionally, the Ti-45Zr alloy presented a good osteointegration ability. Overall, these results confirmed that the Ti-45Zr alloy can be used as a dental implant material.
The recycling process toward the elimination of varistor wastes into new electro‐active silicon composites has been investigated. We studied the dependence of the E‐J characteristics on the aggregate content in the polymer matrix. Formulations with 40 vol.% metal oxide varistor aggregates in the 100‐200 μm range exhibit reliable nonlinear behavior with a switching voltage of 280±30 V/mm. The breakdown voltage of the composite decreases as both filler's diameter and filler's volume fraction increases in the 550‐220 V/mm and 440‐280 V/mm range, respectively. This paves the way for the valorization of varistors based zinc oxide (ZnO) ceramics. 相似文献
Conductance-elongation curves of gold atomic wires are measured using a scanning tunneling microscope break junction technique at room temperature. Landauer's conductance plateaus are individually identified and statistically analyzed. Both the probabilities to observe and the lengths of the two last plateaus (at conductance values close to 2e(2)/h and 4e(2)/h) are studied. All results converge to show that the occurrences of these two conductance plateaus on a conductance-elongation curve are statistically independent events. 相似文献
The purpose of the present study was to determine whether the effect of impulsive and callous personality traits on delinquent behavior varied across neighborhood context in a population-based, statewide sample of 85,000 Iowa schoolchildren ages 10-19. Two previous studies examining the association between impulsivity and delinquency across disadvantaged and affluent neighborhoods have yielded contrasting findings. Results of the present study suggested a robust moderating effect of neighborhood context on personality risk for delinquency. The relation between impulsivity and delinquency was greater in neighborhoods low in collective efficacy compared to neighborhoods high in collective efficacy. A similar interaction was found for callous personality traits, indicating the consistency of the moderating effect of neighborhood context on personality risk for delinquency. Gender differences were also examined, and results were replicated in a holdout sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Fluoroalkyl end-capped acrylic acid oligomers/fullerenes nanocomposites reacted smoothly with tetraethoxysilane (TEOS) and silica nanoparticles under alkaline conditions to give fluoroalkyl end-capped oligomers/silica composites-encapsulated fullerenes. Interestingly, these isolated fluorinated composites were found to afford nanometer size-controlled colloidal particles with a good dispersibility in a variety of organic solvents including water. More interestingly, these fluorinated silica nanocomposites-encapsulated fullerenes were applied to a new type of surface modification agent, and these nanocomposites were able to disperse well above the poly(methyl methacrylate) films to exhibit not only surface active property imparted by fluorine but also a unique characteristic related to fullerenes in the nanocomposites on the surface, effectively. 相似文献
A simple synthetic route is developed to achieve gold functionalized radial mesoporous silica nanoparticles (Au‐MsNP) synthesized by a one step procedure fully compatible with basic conditions required for the preparation of monodispersed nanospheres. In a second step, Au‐MsNP particles have been coated with phospholipid bilayers in order to design an advanced biofunctional platform with the gold metallic nanoparticles previously grown into the pore channels and responsible for a plasmonic activity relevant for biosensing. The size of Au‐MsNP is checked by dynamic light scattering while zeta potential measurements reflect their surface charge. The particle morphology is characterized by transmission and scanning electron microscopy and the Si/Au ratios are obtained from energy dispersive X‐ray analysis. The textural properties of Au‐MsNP, specific surface area and pore size, are determined from N2 adsorption. The supported bilayers are achieved from vesicles of different phospholipids incubated with Au‐MsNP particles. The coating efficiency is investigated by zeta potential and cryo‐ transmission electron microscopy. The plasmonic activities of bare Au‐MsNP particles and coated lipid bilayer Au‐MsNP platform are evidenced for two model systems: direct adsorption of bovine serum albumin and molecular recognition events between avidin molecules and biotin receptors integrated in the supported lipid bilayer. 相似文献
This paper concerns an experimental and theoretical study of the transition between two consecutive conductance plateaus as obtained in breaking gold contact experiments. The experimental measurements performed at 100?K with a scanning tunneling microscope and variable elongation speeds show that the transitions between consecutive plateaus can appear in the conductance traces as an abrupt conductance step, a smooth quasicontinuous change or as large amplitude conductance fluctuations. The theoretical calculations based on a non-orthogonal tight-binding Hamiltonian have shown that for a given deformation there are several structures having close and competing energies.We discuss the relation between the temperature, sampling frequency, stretching speed and energy barriers which can explain the conditions for the observation of the three kinds of conductance traces. 相似文献
Rate control algorithm adopted in H.264/AVC reference software shows several shortcomings that have been highlighted by different studies. For instance, in the baseline profile, the frame target bit-rate estimation assumes similar characteristics for all frames and the quantization parameter determination uses the Mean Absolute Difference for complexity estimation. Consequently, an inefficient bit allocation is performed leading to important quality variation of decoded sequences. A saliency-based rate-control is proposed in this paper to achieve bit-rate saving and improve perceived quality. The saliency map of each frame, simulating the human visual attention by a bottom-up approach, is used at the frame level to adjust the quantization parameter and at the macroblock level to guide the bit allocation process. Simulation results show that the proposed attentional model is well correlated to human behavior. When compared to JM15.0 reference software, at the frame level, the saliency map exploitation achieves bit-rate savings of up to 26%. At the MB level and under the same quality constraint, bit-rate improvement is up to 42% and buffer level variation is reduced by up to 71%. 相似文献