C3和C4植物粗料及底物精粗比对山羊瘤胃体外发酵特性的影响

本试验研究了C3和C4植物粗料及底物精粗比对山羊瘤胃体外发酵特性的影响。采用完全随机区组试验设计,选择不同来源的C3(水稻秸秆和苜蓿)和C4植物(玉米秸秆和宽叶雀稗)为粗料,并分别设计3种不同精粗比(40∶60、45∶55和50∶50)的底物,进行48 h的瘤胃体外发酵试验,测定体外产气参数、发酵特性参数、营养物质降解率。结果表明:1)底物粗料选用苜蓿时,理论最大产气量极显著高于其余3种粗料(P0.01),且以精粗比为45∶55和50∶50时较高;底物粗料选用水稻秸秆时,甲烷(CH4)产量分别比苜蓿、玉米秸秆和宽叶雀稗降低53.79%、24.30%和3.29%,且以精粗比为45∶55时最低。2)C3植物粗料的发酵液p H和氨态氮(NH3-N)浓度均极显著高于C4植物粗料(P0.01);精粗比对发酵液p H和NH3-N浓度均没有显著影响(P0.05)。3)底物粗料选用水稻秸秆时,发酵液乙酸、丙酸和总挥发性脂肪酸浓度均极显著高于玉米秸秆和宽叶雀稗(P0.01),而与苜蓿没有显著差异(P0.05);精粗比为50∶50时水稻秸秆和玉米秸秆发酵液乙酸/丙酸均显著高于精粗比为40∶60(P0.05),而与精粗比为45∶55时没有显著差异(P0.05)。4)各底物体外干物质和中性洗涤纤维降解率均以选用水稻秸秆为底物粗料时最低,分别比苜蓿、玉米秸秆、宽叶雀稗低18.84%、4.37%、3.84%和11.12%、17.78%、15.56%。结果提示,以苜蓿为粗料,精粗比为50∶50的底物瘤胃体外发酵降解率最高,CH4产量也最高;以水稻秸秆为粗料时,精粗比为45∶55的底物瘤胃体外发酵降解率最低,CH4产量也最低。     

Comparative analysis between endometrial proteomes of pregnant and non-pregnant ewes during the peri-implantation period

Background

Early pregnancy failure has a profound impact on both human reproductive health and animal production. 2/3 pregnancy failures occur during the peri-implantation period; however, the underlying mechanism(s) remains unclear. Well-organized modification of the endometrium to a receptive state is critical to establish pregnancy. Aberrant endometrial modification during implantation is thought to be largely responsible for early pregnancy loss.

Result

In this study, using well-managed recipient ewes that received embryo transfer as model, we compared the endometrial proteome between pregnant and non-pregnant ewes during implantation period. After embryo transfer, recipients were assigned as pregnant or non-pregnant ewes according to the presence or absence of an elongated conceptus at Day 17 of pregnancy. By comparing the endometrial proteomic profiles between pregnant and non-pregnant ewes, we identified 94 and 257 differentially expressed proteins (DEPs) in the endometrial caruncular and intercaruncular areas, respectively. Functional analysis showed that the DEPs were mainly associated with immune response, nutrient transport and utilization, as well as proteasome-mediated proteolysis.

Conclusion

These analysis imply that dysfunction of these biological processes or pathways of DEP in the endometrium is highly associated with early pregnancy loss. In addition, many proteins that are essential for the establishment of pregnancy showed dysregulation in the endometrium of non-pregnant ewes. These proteins, as potential candidates, may contribute to early pregnancy loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s40104-015-0017-0) contains supplementary material, which is available to authorized users.     

基于改进形状因子的钵体秧盘播种质量检测方法研究

为实现超级稻育秧播种过程按"穴粒数"播补种的思路,需要对播种钵体秧盘上每个穴位的种子数进行精确检测。传统的单一面积法和平均灰度值法虽然简单,但检测精度较低,无法准确识别每个穴位种子粒数,最终影响播种质量。考虑到种子单个连通区域的形状参数与粒数之间存在密切关系,提出一种基于改进形状因子的钵体秧盘播种质量检测方法。首先采用RGB加权法对彩色图像进行灰度化处理,Otsu分割阈值算法进行二值化,形态学算法进行去噪;再利用掩膜定位技术提取出秧盘中每个穴位内的种子图像并进行连通域检测,测量单个连通域的面积、周长、最小外接多边形面积等参数,计算出改进后的形状因子,结合单连通域面积大小,完成单个连通域种子0粒(含杂质)、1粒、2粒、3粒、4粒及以上情况的检测,并通过累加实现穴粒数的检测。实验结果表明,该方法对于单个连通域内种子数在0~3粒时识别准确率均达到95%以上,4粒以上种子的识别率达到90%;穴粒数的平均检测准确率均达到95%以上,每幅图像平均处理时间为0.518 s,满足在线检测的需求,为后续播补种提供了参考依据。     

热力学效应对水翼云空化非定常特性的影响

为了探究热力学效应对绕翼型云状空化非定常特性的影响,应用数值模拟的方法,分别从翼型周围温度场、空泡半径、当地空化数的角度分析了不同水温下热力学效应对空化发展的影响.依据模型试验使用的物理模型建模,采用考虑热力学效应的空化模型和基于密度修正的湍流模型(DCM)对攻角α₀=8°的水翼进行非定常云状空泡的数值求解,计算得到的空泡形态与试验结果吻合度较高.空化发生时,蒸发吸热使空泡内部温度降低,水体饱和蒸汽压力下降,空化的发展被抑制,最终附着空泡区域变小、变薄.同时,随着水温的升高,空泡半径减小,空泡扩散加剧,空化区域更加模糊.由于流场温度变化会导致流体物理性质的改变,因此采用考虑温度变化的当地空化数σ(T)可以更直观地反映流场温度变化对空化发展阶段的影响.     

丘陵红壤区旱稻需水量试验的研究

应用“坑测法”测定了旱稻需水量 ,结果表明 :中亚热带丘陵红壤地区旱稻需水量为 5 14 .0 mm。该需水量约为同期降雨量的 6 1% ,一般年景不用灌溉。过多过少水量都影响旱稻生长 ;低于 35 0 .0 mm不能成穗。旱稻根系发达 ,吸水吸肥和抗旱能力强 ,特别适宜丘陵地区种植。     

Changes in soil organic carbon and nutrient pools in aggregate-sized fractions along a chronosequence of wolfberry (Lycium barbarum L.) plantations in arid areas of Northwest China

Different land use and management actions can affect soil aggregates (SAs) and nutrient stocks, which are crucial for sustainable agriculture. The impacts of various chrono-sequences on the soil aggregate structure, soil organic carbon (SOC) and nutrients associated with aggregate fractions in wolfberry (Lycium barbarum L.) plantations are still not fully understood. This study examined the composition and stability of SAs, SOC, total nitrogen (TN), available phosphorus (AP) and exchangeable cations (K⁺, Na⁺, Ca²⁺ and Mg²⁺) in bulk soil and various aggregate-size fractions from five wolfberry plantations with varying ages (1, 4, 6, 10 and 13 years) and a corn field (0 years) in the arid region of northwest Ningxia in China. The results indicated that silt–clay (<53 μm) fractions were dominant in the soil, accounting for 51%–66%, under different plantation ages. The proportion of the macro-aggregates (>250 μm) increased significantly, by 40%–47%, over the 4 years of wolfberry plantation. Likewise, the soil aggregate stability was improved, and total exchangeable bases (TEB) along with numerous cations concentrations (K⁺, Na⁺, Ca²⁺ and Mg²⁺) in SAs were significantly reduced as the wolfberry plantings became older. Both concentrations of SOC and TN in the soil aggregates peaked in the 13th year. The silt–clay fractions stored a considerable amount of SOC and nutrients. However, short-term (under 6 years) cultivation of wolfberry reduced the stocks of SOC, TN and AP in the soil, while long-term (over 10 years) cultivation increased them, particularly in macro-aggregates. These findings indicated that long-term wolfberry farming had several advantages, such as enhancing soil structure, accumulating SOC and nutrients and ameliorating alkaline soils, especially after 10 years, in the arid northwest of China.     

Maize straw is more effective than maize straw biochar at improving soil N availability and gross N transformation rate

Soil nitrogen (N) transformation is vital in determining farmland N availability. Although many studies have investigated the effect of biochar on N retention and loss via leaching and gaseous emissions, few have determined the dynamics of gross N transformation during crop growth in long-term biochar-amended soils and compared the effect of the biochar with that of its feedstock. In this study, we conducted a five-time field measurement of soil gross N turnover rates via ¹⁵N isotope pool dilution during maize growth in 2021. Three treatments were employed, including no amendment, biochar and straw applied annually at rates of 2.63 and 7.50 t ha⁻¹, respectively, since 2013. The results showed that biochar did not change the rate of gross N mineralisation when compared with no amendment, but straw increased it by 139% in August, resulting in significantly higher cumulative gross N mineralisation than biochar and no amendment (701 vs 489 and 499 mg kg⁻¹ in 200 d). The inconsistent influence was attributed to the fact that inherent biochar-N was recalcitrant and could not be mineralized like the straw. The gross nitrification rate was decreased by 72.9% and 77.4% by biochar and straw application, respectively, in June relative to no amendment, but then it increased from July to August in the straw treatment as a result of the elevated gross N mineralisation rate. The decreased nitrification in the biochar treatment was an outcome of the synergetic effect of a low ammonium pool (−59.4%) and a high gross ammonium immobilisation rate (+263%), which was likely due to excessive fertilizer N loss and abiotic adsorption to biochar. Meanwhile, biochar amendment inhibited bacterial 16S and fungal ITS genes, as well as ureC and bacterial and archaea-amoA gene copies. In conclusion, straw is more effective than biochar at improving soil N transformation and availability in the long term.     

基于CAN总线的棉花在线测产系统设计

为了及时获取采棉机在作业过程中的产量信息,设计了基于CAN总线技术的棉花在线测产系统,主要介绍了CAN总线监测节点以及针对该测产系统的模块设计。本系统通过目前车载系统流行的CAN总线与监控终端连接并进行通信,能够完成对棉花产量、风速、地速等数据的实时监控。     

棉垛温湿度监测管理系统的设计

为解决籽棉存储过程中棉垛内部温湿度难以实时获取以及传输的问题,利用无线传感技术及多点式实时温湿度采集布设结构,设计了针对棉垛内部温湿度数据实时采集及采集后的决策管理系统,保证籽棉在存储加工过程中的质量。该系统实现了棉垛内部温度湿度数据多点实时采集、决策管理及历史查询等功能,完整地获取了整个棉垛的温湿度信息,提高了管理人员对棉垛的有效控制,降低棉垛变质概率。     

Film morphology of supramolecule CPES/ASO and its performance on cotton substrates

The supramolecule CPES/ASO was self-assembled from carboxylated polyether-block-polydimethylsiloxane (CPES) and N-β-aminoethyl-γ-aminopropyl polysiloxane (ASO) in ethyl acetate solution. The film morphology and performance of CPES/ASO on cotton substrates were investigated by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), X-ray photoelectron microscope (XPS), and so on. The results indicated that a polysiloxane resin film was coated on the treated fiber surface and able to decrease the root mean square roughness (R _q ) of the treated fiber conspicuously. Morphology of higher peaks circled by many smaller peaks was observed on the film surface, which was partly similar to that of CPES/ASO on the silicon wafer. Besides, when the mass ratio of CPES to ASO was 2:1, the fabric treated by CPES/ASO showed the best softness and had a comfortable oily tactile.