Isolation and Characterization of Collagen and Antioxidant Collagen Peptides from Scales of Croceine Croaker (Pseudosciaena crocea)

Acid soluble collagen (ASC) from scales of croceine croaker (ASC-C) was successfully isolated with the yield of 0.37% ± 0.08% (dry weight basis), and characterized as type I collagen on the basis of amino acid analysis and electrophoretic pattern. The antioxidant hydrolysate of ASC-C (ACH) was prepared through a two-stage in vitro digestion (4-h trypsin followed by 4-h pepsin), and three antioxidant peptides (ACH-P1, ACH-P2, and ACH-P3) were further isolated from ACH using ultrafiltration, gel chromatography, and RP-HPLC, and their amino acid sequences were identified as GFRGTIGLVG (ACH-P1), GPAGPAG (ACH-P2), and GFPSG (ACH-P3). ACH-P1, ACH-P2, and ACH-P3 showed good scavenging activities on hydroxyl radical (IC₅₀ 0.293, 0.240, and 0.107 mg/mL, respectively), DPPH radical (IC₅₀ 1.271, 0.675, and 0.283 mg/mL, respectively), superoxide radical (IC₅₀ 0.463, 0.099, and 0.151 mg/mL, respectively), and ABTS radical (IC₅₀ 0.421, 0.309, and 0.210 mg/mL, respectively). ACH-P3 was also effectively against lipid peroxidation in the model system. The antioxidant activities of three collagen peptides were due to the presence of hydrophobic amino acid residues within the peptide sequences. The collagen peptides might be used as antioxidant for the therapy of diseases associated with oxidative stress, or reducing oxidative changes during storage.     

Reactive oxygen and nitrogen species regulate porcine embryo development during pre-implantation period: A mini-review

Significant porcine embryonic loss occurs during conceptus morphological elongation and attachment from d 10 to 20 of pregnancy, which directly decreases the reproductive efficiency of sows. A successful establishment of pregnancy mainly depends on the endometrium receptivity, embryo quality, and utero-placental microenvironment, which requires complex cross-talk between the conceptus and uterus. The understanding of the molecular mechanism regulating the uterine-conceptus communication during porcine conceptus elongation and attachment has developed in the past decades. Reactive oxygen and nitrogen species, which are intracellular reactive metabolites that regulate cell fate decisions and alter their biological functions, have recently reportedly been involved in porcine conceptus elongation and attachment. This mini-review will mainly focus on the recent researches about the role of reactive oxygen and nitrogen species in regulating porcine embryo development during the pre-implantation period.     

保水剂用量对胡杨幼苗生长、光合特性和抗逆生理的影响

[目的]探究极端干旱区保水剂对荒漠植物生长与生理特性的影响,明确荒漠植物生长所需适宜保水剂用量,促进抗旱保墒造林技术在干旱荒漠区生态恢复中的应用.[方法]以胡杨2年生幼苗为研究对象,通过田间干旱试验研究5个聚天冬氨酸(PASP)保水剂用量(0、5、10、15、20 g/株)对胡杨幼苗生长、光合特性、生物量分配和抗逆生理...     

蓄能发光材料在园林工程中的应用探讨

指出了蓄能发光材料是能以某种方式吸收可见光能量,在白天或有光照条件下吸收蓄积光能,夜晚或黑暗时转化光的形式发射的材料。园林景观工程为了丰富城市景色,运用各种园景灯光来丰富夜景,而蓄能发光材料是一种节能型的园林夜景材料,在保持园林工程结构应用性能的基础上,具有夜间发光的景观效果,使发光材料成为园林夜色景观的新亮点。基于此,探讨了蓄能发光材料在园林工程中的应用,以期提供参考。     

变电站二次压板状态在线监测系统

为了减少人为因素引起的压板状态检查核对疏漏给设备安全运行留下隐患,设计了变电站二次压板状态在线监测系统。通过采集压板投退时的电平变化从而达到采集二次压板状态的目的。该系统不但可以直观地显示二次压板状态,还可以在后台系统实现二次压板的巡检、压板状态告警提示等功能,极大地提高了工作人员二次压板检查的效率,减少了人为因素的影响,提高了设备运行的安全性。     

基于云计算的水稻区域试验信息采集系统设计

区域试验为农作物品种审定提供了依据,是作物育种研究与实践应用之间的桥梁。近年来,参试的作物品种数量增加,但试验费用没有相应增长,试验质量无法得到保证。水稻是我国最重要的粮食作物,其面临的问题更为明显。在发展智能农业的背景下,物联网、大数据和云计算等新型技术在农业中得到了应用,并取得良好的成效。为此,基于云计算技术,建立了一个水稻区域试验的信息采集系统,利用云计算对传感器收集的信息进行分析,为区域试验的农艺操作和结果评判提供依据。试验结果表明:云计算采集的水稻数据与人工调查结果都没有明显的差异,可以代替人工采集水稻信息,降低了人力成本,提高了试验质量。     

番茄育苗播种机双腔排种滚筒的性能试验研究

针对现有气吸滚筒式排种器部件多、装配难、密封性差、无正压投种气室,以及难于实现正压投种清堵功能、直接造成排种器漏播率高的的技术问题,提出了利用3D快速成型技术打印剖分式负压吸种滚筒的新思路,并创新设计了双腔排种滚筒。以番茄种子为试验对象,以滚筒转速、滚筒负压和投种腔气室正压为试验因素,进行正交回归试验,并利用Design-Expert软件对试验数据进行方差分析和回归拟合,分析了影响排种性能指标的滚筒负压、滚筒转速和投种腔气室正压的显著性,确定了影响排种性能指标较优的结构参数、工作参数,即当投种腔气室正压为2.2k Pa、滚筒负压为2.4k Pa、滚筒转速为16r/min时,性能指标的最优值及为单粒率93.2%,重播率4.3%,漏播率2.5%,均满足精量排种的技术要求。     

玉米精量播种监测系统的设计与试验

针对玉米精播机作业时常会发生导种管堵塞、地轮排种轴机械传动系统故障及种箱排空造成的漏播等现象,基于单片机技术设计了一套玉米精量播种监测系统,包括整体结构与排种监测传感器电路,完成了相关参数设置。该系统实现了对玉米精播机的播种量、播种速度、播种面积、地轮转速、排种轴转速、种箱料位及机具升降状态等指标的实时监测和漏播故障诊断功能,支持对精播机作业数据远程实时监控管理功能。试验结果表明:玉米精量播种监测系统单粒测量精度约为98.8%,能够实现作业过程的实时监测及远程监管功能。     

基于离散元法的果园开沟刀具的仿真与试验研究

为探究自主研制的果园立式单轴开沟机刀片数量对开沟质量及功耗的影响及刀片在作业过程中受力最大的部位,采用离散元法建立了4刀片刀具开沟过程的仿真模型,并运用转速—扭矩测量平台获得了开沟过程中刀具的真实功耗,得出仿真模型的误差为9.3%,从而验证了离散元法对刀具开沟过程进行模拟的可行性。运用该仿真模型分别对刀片数目为3和5的刀具开沟过程进行了仿真研究,结果表明:当刀片数目为3时刀具的功耗最小,刀片数目为4为时开沟效果最好。通过分析4刀片刀具工作时的受力情况,得知其在工作开始时功耗波动较大,底端刃口处始终受到较大力的作用,因而应对其进行耐磨处理。