In this paper, we deal with a single machine scheduling problems integrating with step deterioration effect and a rate-modifying activity (RMA). The scheduling problem assumes that the machine may have a single RMA and each job has the processing time of a job with deterioration is a step function of the gap between recent RMA and starting time of the job and a deteriorating date that is individual to all jobs. Based on the two scheduling phenomena, we simultaneously determine the schedule of step deteriorating jobs and the position of the RMA to minimize the makespan. To solve the problem, we propose a hybrid typed genetic algorithm compared with conventional GAs.

Bovine oocytes surrounded with compact cumulus cells were cultured for 20 to 22 hours(, 5% ) in modified TCM-199 medium supplemented with 5% superovulated cow serum(SCS) and inseminated by in vitro capacitated spermatozoa. Day 7 to 8 embryos were equilibrated for 10 minutes in 1.3M methyl cellosolve(MC) <1.1M diethylene glycol(DEG), 1.8M ethylene glycol(EG), 1.6M propylene glycol(PG) and 1.1 M 1,3-butylene glycol(BG) solutions. They were then loaded into 0.25ml straws, placed into an alcohol bath freezer at , cooled from to at /minute, seeded, held for 10 minutes, and stored in liquid nitrogen. After thawing in water, the embryos wee rehydrated in TCM-199 medium and then cultured for 48 hours in TCM-199 plus 5% SCS. Embryos were considered viable if they progressed to later developmental stages with a good morphology. Some of the embryos frozen in each cryoprotectant were thawed and transferred non-surgically without removing the cryoprotectant. Hatched embryos survived freezing and one-step dilution as follows : EG(50.0%), MC(53.6%), DEG(56.9%), PG(58.0%) and BG(11.5%). The survival rate of embryos cooled at vs. /minute was not significantly different(P<0.05), however, blastocysts hatched most often (P<0.01) in vitro when cooled at a rate of /minute(64.6%), 31/48) than at /minute(22.6%, 12/53). Pregnancy rates resulting from embryos frozen in the different cryoprotectants were as follows : MC(48%, 10/21); DEG(30%, 3/10); EG(74%, 20/27); and PG(40%, 4/10). These results indicate that MC, DEG, EG and PG have utility as cryoprotectants for the freezing and thawing of IVF Bovine embryos.

This study were carried out to investigate the effective concentration of cryoprotective agents and sucrose by one-step straw method, and to determine the optimum thawing temperature and equilibration time of frozen porcine embryos. The porcine embryos foflowing dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquid nitrogen and thawed in 3 water. Survival rate was defined by FDA test. The results are sunnnarized as follows : 1. The survival rates of porcine embryos after ultrarapid frozen4hawing in the freezing medium with a various concentration of glycerol, DMSO and propanediol added 0.25M sucrose were higher survival rate than those of sucrose concentration of 0.50M. 2. The survival rates of porcine embryos after ultrarapid ftozen4hawing in the freezing medium added 0.25M and 0.SOM sucrose were higher survival rate than those of sucrose concentration of 0.75M and 1.00M. 3. The temperature thawed at 2 and 3 resulted in a significantly higher embryos survival rate after 72 hrs in culture than did at 35. 4. The equilibration time on the survival rate of porcine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time(10~20 min.).