卵巢低温保存时间与不同培养液对小鼠卵母细胞体外发育的影响

为了探讨在4℃条件下,保存卵巢时间与不同培养液对小鼠卵母细胞体外发育的影响,试验比较了在4℃条件下,小鼠卵巢不同保存时间对后续卵母细胞发育的影响,同时对M2和M16两种不同培养液对小鼠卵母细胞体外培养发育效果进行比较。结果表明:随着卵巢保存时间的延长,待成熟受抑制状态的生发泡期(GV期)的卵子所占比例呈上升趋势,减数分裂Ⅱ期(MⅡ期)的卵子所占比例呈下降趋势,4℃低温不同保存时间小鼠卵子体外发育存在差异,4℃保存可延长到18 h,但到24小时时所得卵子发育能力急剧下降。在运用M2和M16两种不同培养液进行卵母细胞体外培养时,M16培养液培养效果略好于M2培养液。

Mechanical properties and microstructural evolution of ultrafine grained zircaloy-4 processed through multiaxial forging at cryogenic temperature

The mechanical properties and microstructural evolution of zircaloy-4 subjected to cumulative strains of 1.48,2.96,4.44 and 5.91 through multiaxial forging（MAF） at cryogenic temperature（77 K） were investigated.The mechanical properties of the MAF treated alloy were measured through universal tensile testing and Vickers hardness testing equipment.The zircaloy-4 deformed up to a cumulative strain of 5.91 showed improvement in both ultimate tensile strength and hardness from 474 MPa to 717 MPa and from HV 190 to HV 238,respectively,as compared with the as-received alloy.However,there was a noticeable decrement in ductility（from 18%to 3.5%） due to the low strain hardening ability of deformed zircaloy-4.The improvement in strength and hardness of the deformed alloy is attributed to the grain size effect and higher dislocation density generated during multiaxial forging.The microstructural evolutions of deformed samples were characterized by optical microscopy and transmission electron microscopy（TEM）.The evolved microstructure at a cumulative strain of 5.91 obtained after MAF up to 12 cycles depicted the formation of ultrafine grains with an average size of 150-250 nm.

不同稀释液对Beagle犬精液保存效果的比较

通过比较4种不含卵黄的犬精液稀释保存液在低温环境中(4℃)的实际使用效果,筛选出适合的不含卵黄低温稀释保存配方。不含卵黄的配方Ⅳ(Tris 2.108 g,柠檬酸水合物1.2 g,果糖1.0 g,青霉素100 mg,双氢链霉素100 mg,牛血清白蛋白(BSA)4 g,加蒸馏水到100 mL)具有较好的低温稀释保存效果,并首次提出牛血清白蛋白(BSA)可作为非常时期犬精液低温稀释液中卵黄的替代物。