基于熵权-逼近理想解排序法结合体外模拟消化评价功能性水稻品质

目的 探究不同品种功能性水稻的品质差异性指标,并进行综合品质评价。方法 以来源于咸宁市农业科学院的7种功能性水稻为研究对象,对其7项基本营养成分、9种矿物质元素含量、3类淀粉含量和1种血糖预测指数共计20项营养品质指标进行对比分析,在利用正交偏最小二乘法-判别分析(orthogonal partial least-squaresdiscriminationanalysis,OPLS-DA)筛选重要差异性指标的基础上,建立熵权-逼近理想解排序法(technique for order preference by similarity to ideal solution, TOPSIS)模型对7种功能性水稻的综合品质进行评价。结果 不同品种功能性水稻的基本营养成分在较小范围内波动,但钾元素含量和淀粉含量的变化范围较大,其中水稻GN 7、GN 5、GN 6在钾元素含量方面表现较好,水稻GN 4、GN 1、GN 3抗性淀粉含量最高,预估血糖生成指数(estimated glycemic index, eGI)值更低,抗消化能力优于其他品种。OPLS-DA分析筛选出锌、钠、钾、抗性淀粉、钙、镁、...     

Eating quality of raw carrots––correlations between flavour compounds,sensory profiling analysis and consumer liking test

Sensory profiling, analysis of aroma, sugar and dry matter, as well as consumer liking test were used to characterise the quality of six carrot cultivars, grown at two locations in Denmark. The carrot samples were examined at harvest, and after three months of cold storage. Carrot cultivar had an effect on most sensory and flavour compound variables, due particularly to the influence of one cultivar; and also location influenced carrot quality. Storage of carrots was characterised by an increase of a range of aroma components, but the changes in flavour compounds were not correspondingly observed by the sensory analysis. By Partial Least Squares Regression (PLSR) two thirds of the flavour compound variables was found to correlate significantly with one or more of the nine sensory attributes; and all of the sensory attributes were significantly correlated with one or more of the consumer liking test variables bitterness, sweetness and liking.     

放射源~(60)Coγ射线的利用效率研究

应用60 Coγ射线照射量率计算法分析比较了4种放射源排列方法和3种辐照操作方式的γ射线利用效率。结果表明,3种操作方式中,换层操作的效率最高,利用率为1.78,其次是分区操作方式,为1.45,源超界的不换层方式最低,为0.85。实行换层操作时,当吊篮高度在1.2m之内时以3层高度收敛排列法(各层间活度比为0.6∶1.8∶0.6)的60 Coγ射线利用率最高,为1.60;当吊篮高度为1.4 m时,3层轻度收敛排列法(0.9∶1.2∶0.9)的60 Coγ射线利用率最高,为1.72;当吊篮高度达到1.6 m时,3层均匀排列法(1∶1∶1)的射线利用率最高,为1.78。     

In situ co-deposition of nickel hexacyanoferrate nanocubes on the reduced graphene oxides for supercapacitors

A facile co-precipitation strategy is developed to prepare nickel hexacyanoferrate nanocubes (NiHCF NBs) supported on the reduced graphene oxide (rGO) in the presence of poly(diallyldimethylammonium chloride) (PDDA). The NiHCF NBs are uniformly deposited on the rGO by electrostatic interaction. Their size can be tuned from 10 nm to 85 nm by changing their content from 32.6% to 68.2%. Under the optimal condition, NiHCF/PDDA/rGO hybrids are composed of 51.4% NiHCF NBs with an average size of 38 nm. The specific capacitance of NiHCF/PDDA/rGO hybrids reaches up to 1320 F g⁻¹ at a discharge density of 0.2 A g⁻¹, more than twice that of the pure NiHCF, as well as slight capacitance decay by 15% at 0.2 A g⁻¹ and excellent cycling stability with 87.2% of its initial capacitance after 10,000 discharge/charge cycles. More importantly, NiHCF/PDDA/rGO hybrids exhibit an ultrahigh energy density of 58.7 Wh kg⁻¹ at the power density of 80 W kg⁻¹. The superior storage energy performance of NiHCF/PDDA/rGO hybrids, such as high specific capacitance, good rate capacity and long cycling stability, positions them as a promising candidate for supercapacitor materials.     

剂量率对辐照牛血清蛋白生化特性和结构的影响

为研究高剂量率对牛血清辐照灭菌中的活性下降的抑制作用,将新生牛血清分别经平均剂量率为60、600 Gy/min钴源和300 k Gy/min电子加速器3种方式辐照30 k Gy后,分析牛血清蛋白的生化特性和结构变化及其与剂量率的关系。结果表明,与未辐照牛血清相比,辐照后蛋白浊度、疏水氨基酸荧光强度、放热峰出峰时间分别从0.742、24.1 u和16.5 min升高至0.802、99.3 u和17.2 min,而蛋白浓度、放热峰温度分别从0.473和76.4℃下降至0.444和74.5℃。电泳分析(SDS-PAGE)显示,600 Gy/min钴源辐照牛血清中相对分子质量为175 k Da和58 k Da的蛋白组分含量明显大于低剂量率辐照牛血清。经扫描电镜(SEM)分析,辐照后牛血清中沉淀部分呈现密集的网络结构,未沉淀部分呈现碎片和球状体混合的形貌结构,低剂量率辐照的样品蛋白球状体形貌不突出。可见高剂量率有抑制辐照灭菌牛血清蛋白分子变性的作用,3种方式中600 Gy/min钴源效果最明显。     

Exploring the relationship between rural village characteristics and Chinese return migrants' participation in farming: Path dependence in rural employment

China's unbalanced growth has caused a gap between urban and rural economic development, which is linked to rural residents migrating to cities in search of better-paid work. Government pro-rural policies over recent years have brought more rural migrants back to their hometowns. This study examines the relationship between village characteristics and return migrants' occupational choices through an analysis of China Labour-force Dynamics Survey (CLDS) 2014 data. The results show that in rural villages where agriculture is the dominant industry, returnees are more likely to engage in farming occupations. The study also reveals that the promoting effect of return migration on rural economic development is subject to general economic conditions of the localities. This study supports the rationality of Chinese government's increasing investment in rural areas. To break out of path dependence for rural development requires the intervention of government forces in order to break through the existing urban-rural dual structure in China.     

Co-precipitation synthesis of nickel cobalt hexacyanoferrate for binder-free high-performance supercapacitor electrodes

Prussian blue analogue with a typical metal-organic framework has been widely used as an electrode material in supercapacitor. In this work, nickel cobalt hexacyanoferrate (Ni₂CoHCF) was grown on nickel foam directly using a simple co-precipitation method. The as-prepared Ni₂CoHCF was tested by transmission electron microscope, scanning electron microscope, X-ray diffraction and X-ray electron energy spectrum. The results showed that Ni₂CoHCF has a unique open face-centered cubic structure. The Ni₂CoHCF was used to set an asymmetric supercapacitor directly. A series of electrochemical tests showed that Ni₂CoHCF had an excellent electrochemical performance. The specific capacitance of the supercapacitor was 585 C g⁻¹ (1300.0 F g⁻¹, 162.5 mAh g⁻¹) at the current density of 0.5 A g⁻¹. After 2000 cycles, it still maintained 85.57% of its initial specific capacitance at the current density of 10 A g⁻¹. The energy density was 30.59 Wh kg⁻¹ at the power density of 378.7 W kg⁻¹. The results show that the supercapacitor constructed by Ni₂CoHCF as an electrode material has high-current charge-discharge capacity, high energy density and long cycle life.     

γ射线和电子束辐照对牛血清蛋白结构的影响

为比较γ射线和电子束对牛血清辐照灭菌后蛋白损伤的差异,将牛血清辐照0~50 k Gy后,测定蛋白浓度、浊度、疏水性以及纯化后白蛋白的二级结构、热稳定性和分子量大小的变化。结果表明,牛血清辐照后蛋白浓度下降,浊度和疏水性上升,电子束辐照的变化幅度低于γ射线。以10 k Gy剂量为转折点,白蛋白的α螺旋含量先升后降,β折叠含量先降后升,变化范围分别为0%~15.2%和40.6%~52.4%。自由卷曲含量始终呈上升趋势。牛血清辐照后白蛋白组分的DSC图出现放热杂峰,出峰时间延长,γ射线辐照的峰温随剂量增加(77.4℃升至79.1℃)而升高,电子束辐照的趋势相反。照后白蛋白在GPC图中出现分布加宽的杂峰。这说明射线和电子束作用使牛血清同时发生交联和降解反应,破坏白蛋白二级结构,牛血清蛋白分子出现疏水基团外露,浊度增加,以及浓度下降的现象。常温辐照时电子束与γ射线效果差异不明显。