Measurement of time-varying electron density of the plasma generated from a small-size cylindrical RDX explosion by Rayleigh microwave scattering

It is challenging to measure the electron density of the unsteady plasma formed by charged particles generated from explosions in the air,because it is transient and on a microsecond time scale.In this study,the time-varying electron density of the plasma generated from a small cylindrical cyclotrimethylenetrinitramine(RDX)explosion in air was measured,based on the principle of microwave Rayleigh scattering.It was found that the evolution of the electron density is related to the diffusion of the detonation products.The application of the Rayleigh microwave scattering principle is an attempt to estimate the electron density in explosively generated plasma.Using the equivalent radius and length of the detonation products in the bright areas of images taken by a high-speed framing camera,the electron density was determined to be of the order of 10^(20)m^(−3).The delay time between the initiation time and the start of variation in the electron-density curve was 2.77–6.93μs.In the time-varying Rayleigh microwave scattering signal curve of the explosively generated plasma,the electron density had two fluctuation processes.The durations of the first stage and the second stage were 11.32μs and 19.20μs,respectively.Both fluctuation processes increased rapidly to a peak value and then rapidly attenuated with time.This revealed the movement characteristics of the charged particles during the explosion.

A NOVEL ZWITTERIONIC SILANE COUPLING AGENT FOR NONTHROMBOGENIC BIOMATERIALS

A novel silane coupling agent bearing sulfobetaine group, N,N-diethyl-N-（3-sulfopropyl）-aminopropyl- trimethoxysilane （DESATS）, was first designed, synthesized and characterized. Its solution property was studied by means of dynamic light scattering. DESATS was successfully bonded onto the surface of the glass and proved by ESCA. Platelet adhesion assay in vitro indicated that the nonthrombogenicity of glass slide modified with DESATS is greatly improved.

One-step approach for full-thickness skin defect reconstruction in rats using minced split-thickness skin grafts with Pelnac overlay

Background:Split-thickness skin grafting is the current gold standard for the treatment of traumatic skin loss.However,for patients with extensive burns,split-thickness skin grafting is limited by donor skin availability.Grafting split-thickness skin minced into micrografts increases the expansion ratio but may reduce wound repair quality.Dermal substitutes such as Pelnac can enhance the healing of full-thickness skin wounds,but their application currently requires two surgeries.The present study investigated whether it is possible to repair full-thickness skin defects and improve wound healing quality in a single surgery using Pelnac as an overlay of minced split-thickness skin grafts in a rat model.Methods:A full-thickness skin defect model was established using male Sprague-Dawley rats of 10 weeks old.The animals were randomly divided into control and experimental groups in which Vaseline gauze and Pelnac,respectively,were overlaid on minced split-thickness skin grafts to repair the defects.Wound healing rate and quality were compared between the two groups.For better illustration of the quality of wound healing,some results were compared with those obtained for normal skin of rats.Results:We found that using Pelnac as an overlay for minced split-thickness skin grafts accelerated wound closure and stimulated cell proliferation and tissue angiogenesis.In addition,this approach enhanced collagen synthesis and increased the formation of basement membrane and dermis as well as the expression of growth factors related to wound healing while reducing scar formation.Conclusions:Using minced split-thickness skin grafts overlaid with Pelnac enables the reconstruction of fullthickness skin defects in a single step and can increase the healing rate while improving the quality of wound healing.