一株产内切菊粉酶菌株培养条件的响应面优化

从新疆石河子盐碱地菊芋生长根际土壤中,分离筛选得到10株具有内切菊粉酶活力的菌株,复筛得到1株高产内切菊粉酶活力菌株,将其命名为G-60。在单因素实验的基础上,采用Plackett-Burman实验法对8个因素进行了显著因素的筛选,结果表明,菊粉浓度、蛋白胨浓度和装液量对内切菊粉酶酶活影响显著;通过最陡爬坡实验及Central Composite Design设计进一步优化,得到最佳发酵产酶条件为:菊粉浓度66.5g/L、蛋白胨浓度29.1g/L、装液量49.38mL,内切菊粉酶活力达24.62U/mL,与优化前相比提高了1.55倍。      

柠檬酸处理对厚皮甜瓜黑斑病的抑制及苯丙烷代谢的作用

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不同加工工艺对临安山核桃营养成分的影响

为探明不同加工工艺对临安山核桃营养成分的影响,运用高效液相色谱、气相色谱法分析其营养成分含量。结果表明,不同加工工艺对山核桃粗蛋白含量影响差异不显著;烘煮工艺、干炒工艺熟制山核桃氨基酸总量较生核桃分别下降14.86%和25.95%。其中人体必需氨基酸总量较生核桃分别下降19.69%和29.96%。干炒工艺较烘煮工艺熟制山核桃氨基酸总量下降13.02%,人体必需氨基酸下降12.79%;烘煮工艺、干炒工艺熟制山核桃分别较生山核桃不饱和脂肪酸含量下降6.43%和18.18%,饱和脂肪酸含量上升40.61%和114.70%。      

Conservation Study of Imprinted Genes in Maize Triparental Heterozygotic Kernels

Genomic imprinting is a classic epigenetic phenomenon related to the uniparental expression of genes. Imprinting variability exists in seeds and can contribute to observed parent-of-origin effects on seed development. Here, we conducted allelic expression of the embryo and endosperm from four crosses at 11 days after pollination (DAP). First, the F1 progeny of B73(♀) × Mo17(♂) and the inducer line CAU5 were used as parents to obtain reciprocal crosses of BM-C/C-BM. Additionally, the F1 progeny of Mo17(♀) × B73(♂) and CAU5 were used as parents to obtain reciprocal crosses of MB-C/C-MB. In total, 192 and 181 imprinted genes were identified in the BM-C/C-BM and MB-C/C-MB crosses, respectively. Then, by comparing the allelic expression of these imprinted genes in the reciprocal crosses of B73 and CAU5 (BC/CB), fifty-one Mo17-added non-conserved genes were identified as exhibiting imprinting variability. Fifty-one B73-added non-conserved genes were also identified by comparing the allelic expression of imprinted genes identified in BM-C/C-BM, MB-C/C-MB and MC/CM crosses. Specific Gene Ontology (GO) terms were not enriched in B73-added/Mo17-added non-conserved genes. Interestingly, the imprinting status of these genes was less conserved across other species. The cis-element distribution, tissue expression and subcellular location were similar between the B73-added/Mo17-added conserved and B73-added/Mo17-added non-conserved imprinted genes. Finally, genotypic and phenotypic analysis of one non-conserved gene showed that the mutation and overexpression of this gene may affect embryo and kernel size, which indicates that these non-conserved genes may also play an important role in kernel development. The findings of this study will be helpful for elucidating the imprinting mechanism of genes involved in maize kernel development.     

米团花花中挥发性成分的GC-MS分析

为了比较不同提取方法和不同试剂对米团花花中的挥发性成分的化学组成,采取水蒸气蒸馏法和超声波法对干米团花的挥发性成分进行提取,并采用GC-MS方法对提取的挥发性成分进行鉴定。结果是不同的方法和不同的试剂提取得到的成分和含量有一定的差异。水蒸气蒸馏法得到了4种挥发性成分,主要是酯类;利用超声波法提取时,乙醚萃取得到11种,二氯甲烷萃取得到21种,石油醚萃取得到15种,主要是烷类。      

闪式提取法提取落叶松树皮中原花青素的研究

利用闪式提取法提取落叶松树皮中的原花青素。研究了乙醇体积分数、料液比、提取时间和提取温度对落叶松树皮中原花青素提取得率的影响。在单因素实验的基础上,运用正交实验对结果进行优化。结果表明,闪式提取法提取落叶松树皮中原花青素的优化条件为:乙醇体积分数为60%,料液比1∶25(g/mL),提取时间为4min,提取温度40℃。在此条件下进行验证实验,原花青素得率达11.42%。该方法操作简单、速度快、得率高,适用于落叶松树皮中原花青素的提取。      

Experimental Study of the Vibration Phenomenon of Compressor Rotor Blade Induced by Inlet Probe Support

An experimental investigation was conducted in order to understand the installation effects of inlet measurement probes on the vibration characteristics of the ...     

三手指拉拔式红花采摘末端执行器的设计

通过分析人手工采摘红花时人手指所处的形态,提出了三手指拉拔式红花采摘末端执行器的设计方案.通过采收期红花物料拉拔特性的测量与统计分析,确定机械采摘红花所需最大拉拔力,并通过红花植株生物特性分析,设计计算末端执行器采摘手指及其它关键部件.利用运动学仿真分析三手指拉拔式末端执行器在工作过程中夹持力、运动位移和时间的关系,最...     

基于区块链的分布式物联网信任管理方法研究

随着物联网(Internet of things, IoT)技术的发展,在不同的物联网之间逐渐形成了大规模、异构化、动态化的分布式物联网环境.分布式物联网内的设备间与物联网管理机构间存在着广泛的合作需求,为此需要在其中建立信任机制以促进合作.然而,现有的信任机制研究大部分脱离于物联网环境,没有考虑物联网设备计算与存储能力有限且差异较大这一特点,造成抽象信任机制研究无法直接应用于物联网中;另一方面,现有的物联网信任问题研究都依赖于额外的可信第三方或域间信任假设,这在实际中是难以实现的.为了解决上述问题,借助区块链与风险理论,提出一种适用于分布式物联网的信任管理方法.具体地,将信任量化为对期望信用与风险的考察,并借助区块链实现信任数据的有效共享与安全性.实验与分析表明:该方案能够有效量化信任,保护数据不被篡改,且能够以较低的存储开销维护系统的正常运行.     

熔渣中Zn、Pb挥发行为的对比分析

熔融工艺是目前处理工业粉尘及飞灰的有效方法.为了能够有效控制熔融工艺中Zn、Pb等重金属资源的分离回收,对比分析了Zn、Pb在含Cl的FeO-CaO-SiO₂-Al₂O₃-Fe₂O₃渣系中的挥发行为.首先通过热力学计算分析了Zn、Pb在该渣系中可能的挥发气体种类,以及各因子如温度、熔渣成分、氧势和Cl含量等的影响.同时,对以上问题进行了实验研究.最终明确了分别提高Zn、Pb挥发分离效率的不同的技术措施和优化参数.