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Objective To evaluate a Zika virus(ZIKV) test based on real-time reverse-transcriptase-polymerase chain reaction (rRT-PCR) that can be performed without RNA isolation. Methods The detection method is based on rRT-PCR technology, and a virus-enrichment method is used for sample processing. The sample processing procedure is: Add 112-224 μL sample treatment solution Ⅰ and 5-10 μL sample treatment solutionⅡ to 100-200 μL clinical samples, vortex and then centrifuge at a speed of 12 000 r/min and a centrifugation radius of 8.6 cm for 5 minutes. After centrifugation, discard the supernatant, add 20 μL of solution to resuspend the precipitate, and then add 10 μL of the resuspended precipitate into the PCR reaction solution(50 μL) for detection. The performance of the assay was evaluated from the aspects of the lower limit of detection, cross reactions, interfering substances and precision. Clinical samples (serum, urine and saliva samples) were collected from the Clinical Laboratory of Peking Union Medical College Hospital, and 1/5 of these samples were randomly selected to simulate clinical samples of ZIKV infection to further evaluate the performance of the method. Results The lower limit of detection(LOD) of the ZIKV assay for MR766 and ZKC2/2016 strains was 101 50% tissue culture infective dose(TCID50)/mL. A panel of 17 potential cross substances was tested and no cross-reactivity was detected. Potential interfering substances including bilirubin (15 mg/L), hemoglobin (100 mg/L), triglycerides (2000 mg/L), IgG (37.5 g/L) and EDTA-Na2(2.5 g/L) were evaluated and no obvious interference was observed. The intra-lots and inter-lots variations that were measured by coefficient of variation (CV), were lower than 10%. A total of 344 clinical samples from the Clinical Laboratory of Peking Union Medical College Hospital were collected; 73 simulated clinical samples of ZIKV infection were constructed. The detection results of 344 samples by this method were consistent with the expected results without false positives and false negatives. Conclusions The detection method for ZIKV has good specificity and repeatability. The detection results are not affected by interfering substances. The LOD meets clinical requirements, and the operation is simple. It can be used as a backup diagnostic tool for ZIKV and it needs to be further verified in real clinical samples.

Due to their exceptional impact resistance, ceramics are extensively used in various fields. However, unavoidable pores, microcracks, and inherent defects can degrade the performance of ceramic materials. A damage model of SiC ceramics under passive confining pressure was constructed based on the Lemaitre strain equivalence principle and the Weibull distribution function. This paper presented a dynamic damage model for SiC ceramics subjected to passive confinement pressure based on the principles of damage mechanics. Additionally, the split Hopkinson pressure bar device was employed to investigate the compressive strength and damage evolution of SiC ceramics at various shock pressures and confinement degrees. The experimental results indicate that constraints can reduce the damage to ceramics. The metal sleeve increased stiffness when compressing the ceramic material, allowing the specimen to convert from brittle–plastic–brittle. When sufficient constraints can be provided, the peak strain decreases gradually with the increase of the impact air pressure. Experimental data showing good agreement with the proposed model validated and analyzed the established model. Thinner boundary constraints cannot maintain the stability of ceramic structures, thicker boundaries do not significantly improve performance, and thicker boundaries can cause more weak areas. This paper provides guidance for the design of encapsulated ceramic composite armor by quantitatively studying the constraint thickness. [ABSTRACT FROM AUTHOR]