Background Bacterial proliferation on the endosseous implants surface presents a new threat to the using of the bone implants. Unfortunately, there is no effective constructed antibacterial coating which is bacterial anti-adhesion substrate-independent or have long-term biofilm inhibition functions. Methods Drug release effect was tested in Chymotrypsin (CMS) solution and S. aureus. We used bacterial inhibition rate assays and protein leakage experiment to analyze the in vitro antibacterial effect of (Montmorillonite/Poly-l-lysine-Chlorhexidine)10 [(MMT/PLL-CHX)10] multilayer film. We used the CCK-8 assay to analyze the effect of (MMT/PLL-CHX)10 multilayer films on the growth and proliferation of rat osteoblasts. Rat orthopaedic implant-related infections model was constructed to test the antimicrobial activity effect of (MMT/PLL-CHX)10 multilayer films in vivo. Results In this study, the (MMT/PLL-CHX)10 multilayer films structure were progressively degraded and showed well concentration-dependent degradation characteristics following incubation with Staphylococcus aureus and CMS solution. Bacterial inhibition rate assays and protein leakage experiment showed high levels of bactericidal activity. While the CCK-8 analysis proved that the (MMT/PLL-CHX)10 multilayer films possess perfect biocompatibility. It is somewhat encouraging that in the in vivo antibacterial tests, the K-wires coated with (MMT/PLL-CHX)10 multilayer films showed lower infections incidence and inflammation than the unmodified group, and all parameters are close to SHAM group. Conclusion (MMT/PLL-CHX)10 multilayer films provides a potential therapeutic method for orthopaedic implant-related infections.

In laser dermatologic surgery, cryogen spray cooling (CSC) is used to avoid laith damage such as scars from skin burning due to the melanin absorption of the laser beam. As the cryogen is fully atomized from the nozzle, evaporation of the droplets may quickly drop the cryogen temperature below −60 °C, depending on the spray distance from the nozzle. Such a low temperature is potential to cold injury for skin. Therefore, spray process should be accurately controlled during clinical practice to achieve sufficient protection and to avoid cold injury. This study presents a numerical analysis of cold injury of skin in cryogen spray cooling for dermatologic laser surgery. The model for cryogen spray cooling of skin, developed early, is extended to include the freezing of skin cells. The model predictions include the movement of the lethal isothermals. The severity of cold injury is then quantified under various clinical conditions. The effect of initial temperature and the spurt duration on possible cold injury of skin are also investigated.

BackgroundBacterial proliferation on the endosseous implants surface presents a new threat to the using of the bone implants. Unfortunately, there is no effective constructed antibacterial coating which is bacterial anti-adhesion substrate-independent or have long-term biofilm inhibition functions. MethodsDrug release effect was tested in CMS solution and S. aureus. We used bacterial inhibition rate assays and protein leakageexperiment to analyze the in vitro antibacterial effect of (MMT/PLL-CHX)10 multilayer film. We used the CCK-8 assay to analyze the effect of (MMT/PLL-CHX)10 multilayer films on the growth and proliferation of rat osteoblasts. Rat orthopaedic implant-related infections model was constructed to test the antimicrobial activity effect of (MMT/PLL-CHX)10 multilayer films in vivo.ResultsIn this study, the (MMT/PLL-CHX)10 multilayer films structure were progressively degraded and showed well concentration-dependent degradation characteristics following incubation with Staphylococcus aureus and CMS solution. Bacterial inhibition rate assays and protein leakageexperiment showed high levels of bactericidal activity. While the CCK-8 analysis proved that the (MMT/PLL-CHX)10 multilayer films possess perfect biocompatibility. It is somewhat encouraging that in the in vivo antibacterial tests, the K-wires coated with (MMT/PLL-CHX)10 multilayer films showed lower infections incidence and inflammation than the unmodified group, and all parameters are close to SHAM group. Conclusion(MMT/PLL-CHX)10 multilayer films provides a potential therapeutic method for orthopaedic implant-related infections.

A system is developed on a 5-axes automatic scanning for ultrasonic test. It is a system with the host-slave and open-loop mode that contains PC and a 5-axes drive card based on single chip microcomputers. The system drives five stepper motors to carry the detector moving paralleling the normal direction of the detected surface to complete the detect task.

As the development of the economic society, the new orbit form such as modern tram track arises at the historic moment. Considering the urban internal environment, a higher request is put forward on vibration and noise reduction. This passage is devoted to analyze the noise reduction performance of the granule material, which gained by recycling the waste rubber. We can draw the following conclusions by comparing the noise value and frequency characteristic analysis in different conditions: the new particle material, the ratio of which is 3mm and 5mm, can suppress the noise in different frequency. Especially, the effect is obvious in high frequency area about 1000Hz to 1500Hz.When the track is under a vertical excitation, the combined structure can suppress the rail acoustic radiation noise obviously within 0 to 4000Hz frequency and 1/3 octave center frequency. The horizontal reduction of the noise will be reduced as the increasing of the distance between the vibration source and the test point.