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In order to obtain the seismic dynamic characteristics of a shallow-bias tunnel with a small space, a series of large-scale shaking table model tests were carried out. The key technology of the test is introduced in detail, for example, similar ratios of model, test equipment, testing model box, testing model, sensor arrangement, seismic waves, and testing system. The results show that the first predominant frequency is similar between measuring points. However, the second predominant frequency is highly different between measuring points. The first and second predominant frequencies gradually decrease with the increasing of input PGA. The rock stratum can shield seismic wave in the high frequency band. The research results provide reference for similar tunnels.

Endowing the conduit with conductivity has been an effective way to stimulate nerve growth and functional recovery. Here, conducting polyaniline (PANi) was used to construct a conductive guidance by coating on the surface of microtubes inserted in a three‐dimensional zein nerve conduit to study the repairing efficacy on peripheral nerve injury. PANi nanoparticles with a size of 20–30 nm were synthesized and coated on the surface of microtubes through layer‐by‐layer deposition. Then, conduits including microtubes with and without PANi coating were implanted into rats to bridge a 10‐mm sciatic nerve defect and autograft as the control group. After 2 months, the conduit with PANicoating improved the recovery of proximal compound muscle action potential significantly in the regenerated nerve compared to the conduit without PANi coating, which was not inferior to the autograft group. However, the repairing efficacy was changed reversely at the fourth month postimplantation. PANi coating fragmented to form debris within or around the regenerated nerves while microtubes seem to degrade completely as observed by H&E staining. In vitro degradation experiment confirmed this process. The PANi nanoparticles could induce cytotoxicity and reactive oxygen species (ROS) generation of both NIH 3T3 cells and macrophage cell line RAW 264.7. These in vitro and in vivo results implied that the nondegradable PANi may occupy the regeneration space and stimulate the inflammatory response in later implantation in vivo. While there was no such risk if the PANi coating keeps in an intact film. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:128–142, 2020.

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The accurate monitoring and quantification of genetically modified organisms (GMOs) are key points for the implementation of labeling regulations, and a certified reference material (CRM) acts as the scaleplate for quantifying the GM contents of foods/feeds and evaluating a GMO analytical method or equipment. Herein we developed a series of CRMs for transgenic rice event G6H1, which possesses insect-resistant and herbicide-tolerant traits. Three G6H1 CRMs were produced by mixing seed powders obtained from homozygous G6H1 and its recipient cultivar Xiushui 110 at mass ratios of 49.825%, 9.967%, and 4.986%. The between-bottle homogeneity and within-bottle homogeneity were thoroughly evaluated with consistent results. The potential DNA degradation in transportation and shelf life were evaluated with an expiration period of at least 12 months. The property values of three CRMs (G6H1a, G6H1b, G6H1c) were given as (49.825 ± 0.448) g/kg, (9.967 ± 1.757) g/kg, and (4.986 ± 1.274 g/kg based on mass fraction ratio, respectively. Furthermore, the three CRMs were characterized with values of (5.01 ± 0.08)%, (1.06 ± 0.22)%, and (0.53 ± 0.11)% based on the copy number ratio using the droplet digital PCR method. All results confirmed that the produced G6H1 matrix-based CRMs are of high quality with precise characterization values and can be used as calibrators in GM rice G6H1 inspection and monitoring and in evaluating new analytical methods or devices targeting the G6H1 event.

In order to obtain the seismic internal force response laws of a shallow-bias tunnel with a small clear distance, the reliability of the numerical simulation is verified by the shaking table model test. e parameter sensitivity of the tunnel is studied by using MIDAS-NX finite element software. e effects of seismic wave peak (0.1 g, 0.2 g, 0.3 g, 0.4 g, 0.5 g, and 0.6 g), existing slope angle (30°, 45°, 60°, and 90°), clear distance (1.0 D, 1.5 D, 2.0 D, and 3.0 D), and excitation mode (X direction, Z direction, XY direction, and XYZ direction) on the internal force response law of the tunnel are studied, respectively. e results show that (1) the shear force gradually increases with the increasing of seismic peak. e amplification is different with different measuring points. (2) Under different existing slope-angle conditions, the variation trend of shear force of the tunnel is similar, but the shear force is different. e existing slope has significant effect on the shear force response of the tunnel, and the degree is different with different slope angles. (3) Under the conditions of 1.5 D and 2.0 D, the shear force response of the tunnel is stronger, but the response of other conditions is relatively weak. e tunnel with 1.5 D to 2.0 D clear distance should be avoided. Different excitation modes have a significant effect on the shear force response of the tunnel. (4) Under the same excitation mode, the different excitation directions also have a significant effect on the shear force response. (5) e shear force response of the tunnel crosssection shows nonlinear variation trend. e shear force response is strongest at the arch shoulder and arch foot of the tunnel. e research results provide a useful reference for the design of antishock and vibration resistance of the tunnel.

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