Objective To clone and analyze the MN/CA9 gene sequence in ICR mice and detect the expressions of MN/CA9 gene in various tissues of ICR mice.Methods The fresh tissues of small intesine, uterrus, skin, musle, liver, pancreas, heart, lung, thymus, spleen, kidney, ovary, stomach ,urinary bladder from ICR mice were obtained , the total RNA was extracted by GIT method, the 1st strand and 2nd strand of cDNA were synthesized, the EcoRⅠ adapters were lingated,the EcoRⅠ ends were phosphorylated, digested with XhoⅠ ,cDNA was ligated into the ZAP expression vector, packaged, planted, screened.The expressions of MN/CA 9 gene in various tissues in mice were detected by RT-PCR.Results A fragment of human MN/CA9 gene was used as probe, and 1.47?10~3 clones were screened with radioactive isotopic ~ 32 P labeled probe, after hybridizations, one positive signal of cDNA was detected and the complete nucleotide sequence contained 1 671 bp was determined (GenBank:AB086322), The nucleotide similarity between mouse and human cDNA (GenBank:Z54349) was 69.1%.The MN/CA9 gene detected by RT-PCR assay (primer: P521-P1193) strongly expressed in small intesine,uterus, musle, pancreas, heart, lung, thymus, spleen, kidney, ovary, stomach,and urinary bladder,meanwhile did not express in skin and liver. Conclusion The expressions of MN/CA9 gene in some tissues of ICR mice are similar to that of human, it can be used to further functional analysis of MN/CA9 gene.

Objective: To evaluate the physical properties of SY-1 silicone elastomer with various ratios of cross-linker to base. Methods: The ratios of cross-linker to base were set at 0.5 %、1 %、 1. 5 %、 2 % 、2. 5 % respectively while other conditions were kept same, then the major physical properties of the elatomer were studied with a tensile tester and ASTMD 2240 method. Results: The elongation(%) due to tension, tensile strength (MPa), laceration strength (kN/m) and hardness (A) of SY-1 silicone elastomer with the ration of 0. 5% of cross-linker to base were 540?47,4. 3?0. 28, 14. 4?2.4 and 18. 0?3. w; those of that with 1% 440 ?54,4.0?0.32,18. 2?3.1 and 24. 0?3. 61 with 1.5% 430?51, 4.1?0. 29, 13.6?2.2 and 25.0?2.1; with 2% 350?46, 2.5?0. 33, 9.0?2.1 and 28.0?1.9; with 2.5% 280?36, 2.0?0. 3, 11.0?2.5 and 29.0? 2.8, respectively. Conclusion: The physical properties of SY-1 silicone elastomer with a ratio of 1% of crosslinker to base are more suitable for prothesis fabrication.

Objective:To study the stress distribution of Magsoft (cushion type) and Magnedisk magnetic attachment. Methods: 2 overdentures were prepared on each of 5 edentulous jaw models. The overdentures were pared and retained with Magnedisk and Magsoft magnetic attachments respectively.Photoelastic analysis was used to study the stress distribution for the implanted complete overdentures. Results: Under the same load, around the implants, the stress under the overdentures retained with Magsoft was lower than that with Magnedisk. Compared with Magnedisk, the stress around the abutments under the overdenture retained with Magsoft were distributed in a more even manner. Conclusion: Magsoft magnetic attachment has better biomechanical characteristic than Magnedisk and can distribute stress more evenly throughout the whole supporting structure for its special cushioned design.