Spore suspension of Streptomyce s griseus AS 818 (10 6/mL)was radiated b y Co 60 -radiation,the radiation dosage was 1?10 4rad.And 5 streptomy cin resis tant mutants (above 50?g/mL) were screened,then the resistant level of mutant RL-4 was induced to 100?g/mL.The number of RL-4 colonizing on soybean roots pl anted on 1% Water agar or in sterile soil was determined.The results showed tha t it could colonize on soybean rhizosphere and rhizoplane for a short period,bu t there is a little difference.When it was examined in 1% Water agar,the numb er of RL-4 raised gradually in soybean rhizoplane in 4 weeks.But when examined in sterile soil,RL-4 reduced about 100 times at the 1 st week,then raised gradually and reached the highest point at the 3 rd week,and decreased aga in at the 4 th week,In the rhizoplane,it reduced gradually from the 1 st week,and couldn't be examined at the 4 th week. Mutant RL-4 couldn't be found in soybean endorhizosphere by tissue printing.

A novel artificial anal sphincter system has been developed to simulate the normal physiology of the human anorectum. With the goal of engineering a safe and reliable device, the model of human colonic blood flow has been built and the relationship between the colonic blood flow rate and the operating occlusion pressure of the anorectum is achieved. The tissue ischemia is analyzed based on constitutive relations for human anorectum. The results suggest that at the planned operating occlusion pressure of less than 4 kPa the artificial anal sphincter should not risk the vascularity of the human colon.
Anal Canal ; blood supply ; physiology ; Blood Flow Velocity ; physiology ; Computer Simulation ; Computer-Aided Design ; Equipment Failure Analysis ; Humans ; Models, Biological ; Prostheses and Implants ; Prosthesis Design