Helium nano-bubble bursting near the nickel surface

We have investigated the expansion and bursting of a helium nano-bubble near the surface of a nickel matrix using a molecular dynamics simulation. The helium atoms erupt from the bubble in an instantaneous and volcano-like process,which leads to surface deformation consisting of cavity formation on the surface, along with modification and atomic rearrangement at the periphery of the cavity. During the kinetic releasing process, the channel may undergo the ＂open＂ and＂close＂ states more than once due to the variation of the stress inside the nano-bubble. The ratio between the number of helium atoms and one of vacancies can directly reflect the releasing rate under different temperatures and crystallographic orientation conditions, respectively. Moreover, a special relationship between the stress and He-to-vacancy ratio is also determined. This model is tested to compare with the experimental result from Hastelloy N alloys implanted by helium ions and satisfactory agreement is obtained.

Nano-bubble hydrogen water:An effective therapeutic agent against inflammation related disease caused by viral infection in zebrafish model

Since the anti-inflammatory effect of hydrogen has been widely known,it was supposed that hydrogen could suppress tissue damage by inhibiting virus-related inflammatory reactions.However,hydrogen is slightly soluble in water,which leads to poor effect of oral hydrogen-rich water therapy.In this study,the nano-bubble hydrogen water(nano-HW)(about 0.7 ppm)was prepared and its therapeutic effect against viral infection was investigated by utilizing spring viraemia of carp virus(SVCV)-infected zebrafish as model.Three-month-old zebrafish were divided into nano-HW treatment-treated group and aquaculture water treated group(control group).The results revealed that the cumulative mortality rate of SVCV-infected zebrafish was reduced by 40%after treatment with nano-bubble hydrogen water,and q RT-PCR results showed that SVCV replication was significantly inhibited.Histopathological examination staining showed that SVCV infection caused tissue damage was greatly alleviated after treatment with nano-bubble hydrogen water.Futhermore,SVCV infection caused reactive oxygen species(ROS)accumulation was significantly reduced upon nano-HW treatment.The level of proinflammatory cytokines IL-1β,IL-8,and TNF-αwas remarkably reduced in the nano-HW-treated group in vivo and in vitro.Taken together,our data demonstrated for the first time that nano-HW could inhibit the inflammatory response caused by viral infection in zebrafish,which suggests that nano-HW can be applied to antiviral research,and provides a novel therapeutic strategy for virus-caused inflammation related disease.

Neon-concentration dependent retarding effect on the recrystallization of irradiated tungsten:Experimental analysis and molecular dynamics simulation

Recrystallization is a critical issue in ITER and future fusion devices as it strongly deteriorates the prop-erties and serving life of tungsten divertor armor.In this work,we investigated the influence of neon on the recrystallization behavior of tungsten and its underlying mechanism by both experimental anal-ysis and molecular dynamics simulation.Rolled tungsten was irradiated by neon ion with energies of 10 and 100 keV and fluences of 1×10^(18)-1×10^(20)m^(−2),followed by isochronal annealing at various temperatures(1473-2073 K)for 1 h.The results indicate that 10 keV neon ion irradiation slightly in-hibits tungsten recrystallization due to the shallow depth distribution of neon(35 nm),whereas 100 keV neon ion irradiation exerts a significant retarding effect on tungsten recrystallization when neon con-centration reaches∼102 appm.Grain boundaries can hardly move with neon concentration reaching 400 appm,above which the retarding effect is very strong and varies little.The retarded recrystallization is mainly attributed to the pinning effect of neon clusters/bubbles on the grain boundary movement dur-ing annealing.Large neon clusters are found to play a predominant role in the retarding effect and the un-clustered neon atoms show a very limited effect on the grain boundary movement.By comparing the neon effects on recrystallization in this work and helium effects reported in the literature,we found that helium exhibits a relatively stronger recrystallization retarding effect than neon.This is because helium is more easily to diffuse into grain boundaries and form larger clusters due to its high diffusivity and low self-trapping energy in tungsten,which can greatly impede the migration of grain boundaries.This work provides a fundamental insight into the neon-concentration dependent recrystallization retarding effect in tungsten and the corresponding underlying atomic-level mechanisms.