No abstract

Burkholderia pseudomallei is an important infectious disease pathogen that can cause melioidosis. Melioidosis is mainly prevalent in Thailand, northern Australia and southern China and has become a global public health problem. Early identification of B. pseudomallei is of great significance for the diagnosis and prognosis of melioidosis. In this study, a simple and visual device combined with lateral flow strip-based recombinase polymerase amplification (LF-RPA) was developed, and the utility of the LF-RPA assay for identifying B. pseudomallei was evaluated. In order to screen out the optimal primer probe, a total of 16 pairs of specific primers targeting the orf2 gene of B. pseudomallei type III secretion system (T3SS) cluster genes were designed for screening, and F1/R3 was selected as an optimal set of primers for the identification of B. pseudomallei, and parameters for LF-RPA were optimized. The LF-RPA can be amplified at 30-45°C and complete the entire reaction in 5-30 min. This reaction does not cross-amplify the DNA of other non-B. pseudomallei species. The limit of detection (LOD) of this assay for B. pseudomallei genomic DNA was as low as 30 femtograms (fg), which was comparable to the results of real-time PCR. Moreover, 21 clinical B. pseudomallei isolates identified by 16S rRNA gene sequencing were retrospectively confirmed by the newly developed LF-RPA system. Our results showed that the newly developed LF-RPA system has a simple and short time of operation and has good application prospect in the identification of B. pseudomallei.

Since the inception of research on hollow silica, the use of hollow nanosilica (HNS) as additives in barrier materials has not been reported. In this study, we evaluated the capacity of HNS as an additive in modified polypropylene (MPP). According to X-ray diffraction (XRD), the crystallinity, tensile strength, and thermal stability of MPP/HNS nanocomposite containing 0.1[Formula: see text]phr HNS approached maximum values. Moreover, the nanocomposite had the best performance in terms of water vapor barrier and oxygen resistance. The reasons for the improvement in barrier performance were discussed. Scanning electron microscopy revealed that HNS at a low content dispersed well in MPP. In conclusion, the synthesized HNS can be used as an additive in barrier materials, and it would have potential applications in the fields of food packaging films and storage containers or materials.

No abstract

In this paper, Monte Carlo method combined with the random critical-core probability model is proposed to calculate the longitudinal tensile strength of unidirectional composites. This method considers two-dimensional distribution of fibers on the cross-section, while the theoretical analysis method only takes the linear distribution of fibers into account. Using the weakest link principle, the failure probability and average strength of the unidirectional composites are obtained. The results show that the calculated values of longitudinal tensile strength of T300/5208 composite and unidirectional C/C composites agree well with the experimental results.