To investigate the aging behavior of fluoroelastomer FM-1D in hot air,with compression set as a parameter for seal aging,aging tests were conducted on fluoroelastomer FM-1D under different initial compression rates in a hot air environment ranging from 60℃to 150℃.The aging kinetic equation relating compression set of FM-1D to temperature and time was established,in order to predict its aging life at 25℃.The test results indicated that when the initial compression rate was 30%,the compression set exhibited an Arrhenius relationship with both test temperature and time.However,at a initial compression rate of 50%,the compression set gradually conformed to the Arrhenius relationship as time extended.These findings provide a reference for determining accelerated testing methods and maintenance cycles for FM-1D rubber materials.

To evaluate the aging life of silicone rubber sealing materials in the electrolytic water environment,the compression permanent distortion was taken as the performance change parameter of the sealing ring.Three typical silicone rubber materials,G146,G199,and 6144,were subjected to aging tests in the electrolytic water.The aging data was analyzed by the Arrhenius equation.And the aging kinetics equation of permanent compression deformation retention rate and temperature time was established,the aging life of silicone rubber sealing materials at 25℃was predicted.The results indicate the aging life of G146,G199,and 6144,was 21.3 a,9.8 a,and 12.0 a respectively.These prediction results provide a reference for determining the maintenance cycle of the sealing material.

Objective:To investigate the pregnancy outcome of mosaic embryo transfer in next-generation sequencing (NGS) based-preimplantation genetic testing (PGT), and the effect of different mosaic ratios and types on the pregnancy outcome.Methods:This was a retrospective, single-center, cohort study of 308 mosaic embryo transfer cycles (named mosaic group) and 904 euploid embryo transfer cycles (named euploid group) from January 2018 to December 2021 at Center for Reproductive Medicine, Cheeloo College of Medicine. Pregnancy outcomes, including biochemical pregnancy, clinical pregnancy, ongoing pregnancy, early miscarriage, live birth and pregnancy complication rate, were compared between the mosaic and euploid groups. The mosaic group was further divided into low- and high-level mosaicism subgroups according to mosaic ratio, and fragmental deletion/duplication, chromosomal monosomy/trisomy and complex mosaicism subgroups according to the chimerism type, in order to analyze the effects of different mosaic ratios and types on the transfer outcome of mosaic embryos.Results:Compared with euploid group, the rates of ongoing pregnancy [49.35% (152/308) vs. 58.19% (526/904), P=0.020, OR=0.924] and live birth [48.38% (149/308) vs. 55.75% (504/904), P=0.031, OR=0.930] were significantly lower in mosaic group, but there was no significant difference in the risk of pregnancy complications between the two groups ( P>0.05). The high-level mosaic subgroup had a significantly lower live birth rate [35.00% (14/40)] compared with low-level mosaic subgroup [50.37% (135/268), P=0.028, OR=0.840]. The biochemical pregnancy rate [58.49% (62/106) vs. 70.91% (641/904), P=0.020, OR=0.891], the clinical pregnancy rate [49.06% (52/106) vs. 64.82% (586/904), P=0.003, OR=0.864], the ongoing pregnancy rate [43.40% (46/106) vs. 58.19% (526/904), P=0.003, OR=0.864] and the live birth rate [43.40% (46/106) vs. 55.75% (504/904), P=0.008, OR=0.868] of chromosomal monosomy/trisomy mosaic subgroup were significantly lower than those of euploid group. The biochemical pregnancy rate [64.47% (49/76) vs. 84.13% (53/63), P=0.002, OR=0.793], the clinical pregnancy rate [57.89% (44/76) vs. 77.78% (49/63), P=0.006, OR=0.814], the ongoing pregnancy rate [47.37% (36/76) vs. 68.25% (43/69), P=0.017, OR=0.829] and the live birth rate [46.05% (35/76) vs. 65.08% (41/63), P=0.042, OR=0.850] of fragmental deletion mosaic embryos were significantly lower than those of fragmental duplication mosaic embryos. Conclusion:Partial mosaic embryo transfer can also achieve healthy live births, and different mosaic ratios and types affect the pregnancy outcomes. Therefore, patients with no available euploid embryos could be counseled about the possibility of transferring a mosaic embryo, taking into consideration the different mosaic ratios and types.

Objective:To investigate the pregnancy outcome of mosaic embryo transfer in next-generation sequencing (NGS) based-preimplantation genetic testing (PGT), and the effect of different mosaic ratios and types on the pregnancy outcome.Methods:This was a retrospective, single-center, cohort study of 308 mosaic embryo transfer cycles (named mosaic group) and 904 euploid embryo transfer cycles (named euploid group) from January 2018 to December 2021 at Center for Reproductive Medicine, Cheeloo College of Medicine. Pregnancy outcomes, including biochemical pregnancy, clinical pregnancy, ongoing pregnancy, early miscarriage, live birth and pregnancy complication rate, were compared between the mosaic and euploid groups. The mosaic group was further divided into low- and high-level mosaicism subgroups according to mosaic ratio, and fragmental deletion/duplication, chromosomal monosomy/trisomy and complex mosaicism subgroups according to the chimerism type, in order to analyze the effects of different mosaic ratios and types on the transfer outcome of mosaic embryos.Results:Compared with euploid group, the rates of ongoing pregnancy [49.35% (152/308) vs. 58.19% (526/904), P=0.020, OR=0.924] and live birth [48.38% (149/308) vs. 55.75% (504/904), P=0.031, OR=0.930] were significantly lower in mosaic group, but there was no significant difference in the risk of pregnancy complications between the two groups ( P>0.05). The high-level mosaic subgroup had a significantly lower live birth rate [35.00% (14/40)] compared with low-level mosaic subgroup [50.37% (135/268), P=0.028, OR=0.840]. The biochemical pregnancy rate [58.49% (62/106) vs. 70.91% (641/904), P=0.020, OR=0.891], the clinical pregnancy rate [49.06% (52/106) vs. 64.82% (586/904), P=0.003, OR=0.864], the ongoing pregnancy rate [43.40% (46/106) vs. 58.19% (526/904), P=0.003, OR=0.864] and the live birth rate [43.40% (46/106) vs. 55.75% (504/904), P=0.008, OR=0.868] of chromosomal monosomy/trisomy mosaic subgroup were significantly lower than those of euploid group. The biochemical pregnancy rate [64.47% (49/76) vs. 84.13% (53/63), P=0.002, OR=0.793], the clinical pregnancy rate [57.89% (44/76) vs. 77.78% (49/63), P=0.006, OR=0.814], the ongoing pregnancy rate [47.37% (36/76) vs. 68.25% (43/69), P=0.017, OR=0.829] and the live birth rate [46.05% (35/76) vs. 65.08% (41/63), P=0.042, OR=0.850] of fragmental deletion mosaic embryos were significantly lower than those of fragmental duplication mosaic embryos. Conclusion:Partial mosaic embryo transfer can also achieve healthy live births, and different mosaic ratios and types affect the pregnancy outcomes. Therefore, patients with no available euploid embryos could be counseled about the possibility of transferring a mosaic embryo, taking into consideration the different mosaic ratios and types.

Objective To evaluate a normative and systematic training mode for teachers of community general practice.Methods A total of 16 general practice teachers,who came from Fenglin community health service centre in Shanghai,participated three-stage training mode during March 2011 to February 2012.The clinical competence evaluation and questionnaire survey were conducted before and after training.Fifty trainees trained by the teachers also received clinical competence evaluation.Results After the three-stage training,the test score in medical knowledge,physical examination and clinical skills of the teachers did not change significantly (P =0.794,0.674 and 0.326).The self assessment questionnaire survey of general practice teachers indicated a significant increase,especially in practice capability (t =-2.840,P =0.015) and overall quality (t =-3.017,P =0.011).After training by the teachers,the medical knowledge (t =-9.200,P =0.000),physical examination (t =-9.947,P =0.000) and clinical skills (t =-14.828,P =0.000) of 50 trainees increased markedly.Conclusions Differed from conventional training courses,the three-stage training enhances teaching ability and overall quality of community general practice teachers,and provides a effective training model.