Lamb Waves Propagation Characteristics in Functionally Graded Sandwich Plates.

Functionally graded materials (FGM) have received extensive attention in recent years due to their excellent mechanical properties. In this research, the theoretical process of calculating the propagation characteristics of Lamb waves in FGM sandwich plates is deduced by combining the FGM volume fraction curve and Legendre polynomial series expansion method. In this proposed method, the FGM plate does not have to be sliced into multiple layers. Numerical results are given in detail, and the Lamb wave dispersion curves are extracted. For comparison, the Lamb wave dispersion curve of the sliced layer model for the FGM sandwich plate is obtained by the global matrix method. Meanwhile, the FGM sandwich plate was subjected to finite element simulation, also based on the layered-plate model. The acoustic characteristics detection experiment was performed by simulation through a defocusing measurement. Thus, the Lamb wave dispersion curves were obtained by V(f, z) analysis. Finally, the influence of the change in the gradient function on the Lamb wave dispersion curves will be discussed.

Ultrasonic reflection characteristics of Lithium-ion battery based on Legendre orthogonal polynomial method.

Mechanical properties such as density and Young's modulus of lithium-ion battery electrodes are related to the state of charge (SOC). Characterizing the battery SOC by means of ultrasonic non-destructive testing can obtain the relationship between wave propagation information and the SOC. During the battery charging process, the Young's modulus and density of the internal electrode material will change, which will affect the propagation of ultrasonic waves in the battery. In this research, a clear and more comprehensive description of the reflection characteristics of ultrasonic waves in lithium-ion batteries have been presented. The Legendre orthogonal polynomial method (LOPM) was first introduced to solve the reflection coefficients of single- and multi-cell lithium-ion batteries. The angular spectrum and frequency spectrum of which were regularly shifted with the SOC, so the SOC could be characterized accordingly. The results obtained by finite element simulation were highly consistent with the method used. Moreover, an ultrasonic reflection experiment system was built, which the result matched with theoretical calculation in a customized battery, further verified the feasibility of the method.

Measurement of circumferential Lamb waves using a line-focus poly(vinylidene fluoride) transducer and cross correlation waveform analysis.

This paper presents a method for measuring circumferential Lamb waves propagating on a cylindrically curved thin plate. The measurement is carried out using a wideband and line-focused poly(vinylidene fluoride) transducer along with a defocusing waveform measurement method. After synthesizing the acquired waveforms, interference patterns can be obtained and a cross correlation method is developed to accurately extract the wave velocity as a function of wave frequency. Using three stainless steel thin plates of different thicknesses (100, 150, and 300 µm) and a radius of curvature of 10 mm, dispersion curves for several fundamental and higher order modes of circumferential Lamb waves are simultaneously determined. Theoretical dispersion curves are also calculated and compared with their experimental counterparts. Very good agreements are observed, which concludes the measurement accuracy of this measurement method.

Deregulated expression of miR-224 and its target gene: CD59 predicts outcome of diffuse large B-cell lymphoma patients treated with R-CHOP.

miRNAs are non-coding RNA molecules; their deregulations may contribute to cancer pathogenesis. However, the mechanisms of how miRNA dysfunction contributes to the lymphomagenesis of diffuse large B-cell lymphoma (DLBCL) are not well established. In this study, we analyzed the expression of miR-224 in four DLBCL cell lines and 168 patients' specimens. We found that the expression of miR-224 in DLBCL was down-regulated compared with normal B-cell but was not statistically different between the germinal center B-cell-like-type and the activated B-cell-like-type. Using bioinformatics prediction and luciferase report assays, we demonstrated that miR-224 directly down-regulated CD59 expression by binding to its 3'-untranslated region. We also used immunohistochemical staining of CD59 in human DLBCL specimens and analyzed the relationship between the expression of miR-224, CD59 and the overall/progress-free survival of DLBCL patients who were uniformly treated with rituximab,cyclophosphamide, adriamycin, vincristine, and prednisone (R-CHOP). We found that miR-224 may contribute to DLBCL pathogenesis. Most importantly, the expression of miR-224 and CD59 can predict the response and outcome of DLBCL patients treated with R-CHOP.

Fabrication of broadband poly(vinylidene difluoride-trifluroethylene) line-focus ultrasonic transducers for surface acoustic wave measurements of anisotropy of a (100) silicon wafer.

This paper investigates a new method for fabrication of broadband line-focus ultrasonic transducers by sol-gel spin-coating the poly(vinylidene difluoride-trifluroethylene) [P(VDF-TrFE)] copolymer film on a concave fine-polished beryllium copper backing. The ferroelectric hysteresis loops of the P(VDF-TrFE) films spin-coated from different molar ratios of VDF/TrFE, 77/23 and 55/45, were measured to select the better mixture. Owing to the better acoustic matching to water, compared with lead zirconate titanate (PZT), the fabricated transducers show relatively wide bandwidth of approximately 50 MHz with high central frequency of 60 MHz obtained at the focal plane when a fused-quartz acts as a reflecting target. Each one of the two finished transducers has a focal length of 5mm and a full aperture angle of 90°. After applying the specially developed digital signal processing algorithm to the defocusing experiment data, which is called V(f,z) analysis method based on two-dimensional fast Fourier transform (2-D FFT), the operating frequency can extend from several MHz to over 90 MHz. Surface acoustic wave (SAW) velocities of a typical (100) silicon wafer was measured along various directions between [100] and [010] to represent the anisotropic features.

Macrophage apoptosis associated with Salmonella enterica serovar Typhi plasmid.

The present study was undertaken to investigate the relationship between plasmid isolated from S. enterica serovar Typhi (pR(ST98)) and macrophage apoptosis. pR(ST98) was transferred into an attenuated S. enterica serovar Typhimurium strain RIA to create a transconjugant pRsT98/RIA. Standard S. enterica serovar Typhimurium virulence strain SR-11 was used as a positive control, and RIA as a negative one. Murine macrophage-like cell line (J774A.1) was used as an infectious cell model in vitro. In order to determine the inhibition and bactericidal effect of amikacin (AMK) to extracellular bacteria and the best optimization co-culture ratio between Salmonella and J774A.1, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of AMK to strains SR-11, pR(ST98)/RIA and RIA and multiplicity of infection (MOI) were detected first, and then J774A.1 was infected by the above three serovar Typhimurium strains. Apoptosis of J774A.1 was examined with electron microscopy and flow cytometry after annexin-V/propidium iodide labeling at 0, 1, 3, 6, 12 and 24 h. Mitochondrial membrane potential was detected by JC-1 staining method. It was demonstrated that MIC of AMK to the three strains was 10 microg/ml, MBC was 80 microg/ml, and optimal MOI was 100:1. pR(ST98)/RIA resulted in a higher apoptosis of J774A.1 than RIA, apoptotic features such as chromatin margination could be observed after 3 h, and death of J774A.1 cells was associated with the loss of mitochondrial membrane potential. These results indicated that pR(ST98) could enhance the virulence of its host bacteria, evidenced by increased macrophage apoptosis.