High survival of bovine mature oocytes after nylon mesh vitrification,as assessed by intracytoplasmic sperm injection

Intracytoplasmic sperm injection (ICSI) is an alternative technique to in vitro fertilization (IVF) for producing transferable blastocysts, especially in combination with cryopreserved oocytes, when the IVF system does not work sufficiently. The present study was conducted to directly compare the efficacy of producing bovine blastocysts by ICSI and IVF from vitrified-warmed and fresh oocytes. Denuded oocytes with a detectable first polar body were vitrified-warmed using a nylon mesh device. In the non-vitrified control group, blastocyst yields 8 days after IVF and ICSI were 32.0 and 26.8%, respectively. Oocyte vitrification and subsequent IVF resulted in an impaired blastocyst yield (15.0%); however, such a loss of efficacy due to vitrification was not observed in the ICSI group (blastocyst yield, 25.2%). The alignment of cortical granules beneath the oolemma was comparable between the fresh control and vitrified-warmed oocytes. Here, we report the high survival of vitrified-warmed bovine oocytes, as assessed by ICSI.     

试论黄河中游粗泥沙集中来源区拦沙工程体系布局

通过对粗泥沙集中来源区拦沙工程建设成就与问题的分析,结合粗泥沙集中来源区沟道特征,提出了粗泥沙集中来源区拦沙工程体系的构成、布局思路、建设原则,提出了“先大后小”、“先下后上”和“分段实施”的拦沙工程建设时序,并针对当前工作实际,提出了亟待解决的几个问题:加快大型拦泥库前期工作步伐、尽快制定大型拦泥库标准、重视各类工程实施进度以及正确理解和执行规范、充分发挥骨干坝的作用等。     

Pre- and postoperative radiographic and computed tomographic evaluation of dogs with medial patellar luxation

OBJECTIVE: To quantify, using radiographic and computed tomographic (CT) techniques, the effects of surgical procedures most commonly combined to treat dogs with medial patellar luxation (MPL). STUDY DESIGN: Prospective study. METHODS: Six dogs with 8 MPL were studied. Radiographs and CT of the pelvic limbs were obtained before and immediately after soft-tissue reconstruction, trochlear wedge recession, and tibial crest transposition. Radiographic measurements included angle of inclination, Norberg angle, quadriceps angle (QA), anteversion angle, ratio of the length of the patellar tendon (PT) to the length of the patella, and change in patella tendon angle. CT measurements included angle of inclination, Norberg angle, QA, anteversion angle, depth of the femoral trochlear groove, ratio of the middle femoral trochlear groove depth to the patella thickness, and tibial crest alignment. RESULTS: Conformation of the coxofemoral joint was not affected by surgery. Surgical treatment corrected the QA by 33-58%. Trochlear wedge recession was most effective in deepening the proximal trochlea by 103.5%. The ratio of the middle femoral trochlear groove depth to the thickness of the patella postoperatively resulted in 50% coverage of the patella. Tibial crest transposition resulted in caudalization of the PT by 8.5+/-3.0 degrees, with lateralization of the tibial tuberosity of 11.3 degrees. CONCLUSION: The effects of surgery for MPL can be quantified with radiographic and CT measurements. Surgical correction restored the alignment of the quadriceps and adequately deepened the femoral trochlear groove. Tibial crest transposition resulted in caudalization of the patella tendon and lateralization of the tibial tuberosity. CLINICAL RELEVANCE: These pilot data quantified the effects of surgical procedures most commonly combined to treat MPL. We hope to use these measurements to correlate surgical treatment with functional outcome and postoperative occurrence of luxation.     

电动叶菜收获机自动对行控制系统研究

为提高叶菜收获机智能化控制性能、降低劳动强度,设计了一套电动叶菜收获机自动对行控制系统.通过建立电动叶菜收获机转向机构数学模型和设计对行探测机构,采用PID和模糊控制技术建立了自动对行系统控制策略,并进行了仿真试验和田间试验.试验结果表明:在叶菜行发生偏移时,系统能及时调整行走轨迹,实现自动对行功能,提高了电动叶菜收获...     

黄河中游多沙粗沙区输沙模数变化分析

该文根据绘制的黄河中游输沙模数与粗泥沙模数等值线图,研究分析了黄河中游多沙粗沙区输沙模数与粗沙模数变化规律。     

多沙粗沙区露天煤矿水土保持生态效应的监测评价

[目的]通过开展露天煤矿水土保持生态效应监测评价,判定水土保持措施防护效果及其可行性。[方法]以陕西省神榆矿区西湾露天煤矿为例,以实际监测数据为支撑,从调水效益、保土效益和植被恢复3个方面建立了评价指标体系。采用德尔菲法确定了指标权重,利用线性加权求和法建立综合评价模型,最终计算得出该项目不同建设时期水土保持生态效应值。[结果]生态效应值为运行期(0.683)试运行期(0.344)施工前期(0.213);工程实施以来,治理总面积349.72 hm~2,治理前后,水土流失面积由426.71 hm~2下降到376.63 hm~2,植被覆盖度由20.20%上升到27.18%,拦蓄径流量增加了7 530 m~3,保土量增加了6.90×10~4 t。[结论]陕西省神榆矿区西湾露天煤矿通过实施水土保持方案设计的水土保持工程、植物等措施防护体系,取得了良好的治理效果和生态效应。     

Variations of soil organic carbon fractions in response to conservative vegetation successions on the Loess Plateau of China

Land use changes profoundly affect the equilibrium of soil organic carbon (SOC) sequestration and greenhouse gas emissions. With the current global climatic changes, it is vital to understand the influence of ecological restoration and conservation management on the dynamics of SOC under different land uses, especially in erosion-endangered Loess soils. Therefore, we investigated changes in SOC through a suit of labile fractions, namely: light fraction organic C (LFOC), heavy fraction organic C (HFOC), coarse particulate organic C (CPOC), fine particulate organic C (FPOC), and dissolved organic C (DOC), from two forests i.e., Robinia pseudoacacia (RP) and Platycladus orientalis (PO), with different ages, in comparison with farmland (FL). The SOC and STN contents significantly increased over 42 years in the RP forest where the contents of CPOC and FPOC were significantly higher than in the FL. Moreover, total SOC and its labile fractions, in the studied land use types, significantly correlated with soil CaCO₃, pH, and STN contents, indicating their key roles in SOC sequestration. The results reported here from different vegetation with different ages provide a better understanding of SOC and STN alterations at different stages of vegetation restoration. Our findings suggest that long-term natural vegetation restoration could be an effective approach for SOC sequestration and soil conservation on the Loess soil.