Cellular interplay to 3D in vitro microphysiological disease model:cell patterning microbiota-gut-brain axis

The microbiota-gut-brain axis(MGBA)has emerged as a key prospect in the bidirectional communication between two major organ systems:the brain and the gut.Homeostasis between the two organ systems allows the body to function without disease,whereas dysbiosis has long-standing evidence of etiopathological conditions.The most common communication paths are the microbial release of metabolites,soluble neurotransmitters,and immune cells.However,each pathway is intertwined with a complex one.With the emergence of in vitro models and the popularity of three-dimensional(3D)cultures and Transwells,engineering has become easier for the scientific understanding of neurodegenerative diseases.This paper briefly retraces the possible communication pathways between the gut microbiome and the brain.It further elaborates on three major diseases:autism spectrum disorder,Parkinson’s disease,and Alzheimer’s disease,which are prevalent in children and the elderly.These diseases also decrease patients’quality of life.Hence,understanding them more deeply with respect to current advances in in vitro modeling is crucial for understanding the diseases.Remodeling of MGBA in the laboratory uses many molecular technologies and biomaterial advances.Spheroids and organoids provide a more realistic picture of the cell and tissue structure than monolayers.Combining them with the Transwell system offers the advantage of compartmentalizing the two systems(apical and basal)while allowing physical and chemical cues between them.Cutting-edge technologies,such as bioprinting and microfluidic chips,might be the future of in vitro modeling,as they provide dynamicity.

Heyingwuzi formulation alleviates diabetic retinopathy by promoting mitophagy via the HIF-1α/BNIP3/NIX axis

BACKGROUND Diabetic retinopathy(DR)is the primary cause of visual problems in patients with diabetes.The Heyingwuzi formulation(HYWZF)is effective against DR.AIM To determine the HYWZF prevention mechanisms,especially those underlying mitophagy.METHODS Human retinal capillary endothelial cells(HRCECs)were treated with high glucose(hg),HYWZF serum,PX-478,or Mdivi-1 in vitro.Then,cell counting kit-8,transwell,and tube formation assays were used to evaluate HRCEC proliferation,invasion,and tube formation,respectively.Transmission electron microscopy was used to assess mitochondrial morphology,and Western blotting was used to determine the protein levels.Flow cytometry was used to assess cell apoptosis,reactive oxygen species(ROS)production,and mitochondrial membrane potential.Moreover,C57BL/6 mice were established in vivo using streptozotocin and treated with HYWZF for four weeks.Blood glucose levels and body weight were monitored continuously.Changes in retinal characteristics were evaluated using hematoxylin and eosin,tar violet,and periodic acid-Schiff staining.Protein levels in retinal tissues were determined via Western blotting,immunohistochemistry,and immunostaining.RESULTS HYWZF inhibited excessive ROS production,apoptosis,tube formation,and invasion in hg-induced HRCECs via mitochondrial autophagy in vitro.It increased the mRNA expression levels of BCL2-interacting protein 3(BNIP3),FUN14 domain-containing 1,BNIP3-like(BNIP3L,also known as NIX),PARKIN,PTEN-induced kinase 1,and hypoxia-inducible factor(HIF)-1α.Moreover,it downregulated the protein levels of vascular endothelial cell growth factor and increased the light chain 3-II/I ratio.However,PX-478 and Mdivi-1 reversed these effects.Additionally,PX-478 and Mdivi-1 rescued the effects of HYWZF by decreasing oxidative stress and apoptosis and increasing mitophagy.HYWZF intervention improved the symptoms of diabetes,tissue damage,number of acellular capillaries,and oxidative stress in vivo.Furthermore,in vivo experiments confirmed the results of in vitro experiments.CONCLUSION HYWZF alleviated DR and associated damage by promoting mitophagy via the HIF-1α/BNIP3/NIX axis.

Elaidic acid-induced intestinal barrier damage led to gut-liver axis derangement and triggered NLRP3 inflammasome in the liver of SD rats

Previous studies have shown that trans fatty acids(TFA) are associated with several chronic diseases,the gut microbiota is directly influenced by dietary components and linked to chronic diseases.Our research investigated the effects of elaidic acid(EA),a typical TFA,on the gut microbiota to understand the underlying mechanisms of TFA-related chronic diseases.16S rDNA gene sequencing on faecal samples from Sprague-Dawley rats were performed to explore the composition change of the gut microbiota by EA gavage for 4 weeks.The results showed that the intake of EA increased the abundance of well-documented harmful bacteria,such as Proteobacteria,Anaerotruncus,Oscillibacter and Desulfovibrionaceae.Plus,EA induced translocation of lipopolysaccharides(LPS) and the above pathogenic bacteria,disrupted the intestinal barrier,led to gut-liver axis derangement and TLR4 pathway activation in the liver.Overall,EA induced intestinal barrier damage and regulated TLR4-MyD88-NF-κB/MAPK pathways in the liver of SD rats,leading to the activation of NLRP3 inflammasome and inflammatory liver damage.

Mechanism of Yanghe Pingchaun granules on airway remodeling in asthmatic rats based on IL-6/JAK2/STAT3 signaling axis

Objective: To investigate the effects of Yanghe Pingchuan Granules on airway remodeling in asthmatic rats, and to explore the mechanism of Interleukin-6/Janus kinase 2/ Signal transducing activator of transcription 3(IL-6/JAK2/STAT3) signal axis. Methods: We separated 42 healthy male SD rats into two groups, a control group (7) and a model group (35).The model group was sensitized with a combination of ovalbumin (OVA) and aluminum hydroxide for 2 weeks, while the control group was given an equal amount of physiological saline.After 2 weeks, the modeling group was randomly divided into Model group, Yanghe Pingchuan Granules high, medium and low dose groups and Dexamethasone group, each group consisted of 7 animals. After 4 weeks, OVA atomization and gavage were used for stimulation and treatment. Yanghe Pingchuan Granules high, middle and low groups were given 15.48, 7.74, 3.87 g∙kg-1 Yanghe Pingchuan Granules daily, dexamethasone group was given 0.0625 mg∙kg-1 dexamethasone daily, and the other groups were given the same amount of normal saline. HE, PAS and Masson staining were used to observe the lung histopathological changes in rats. The levels of interleukin-6, IL-23 and IL-17A were detected by ELISA. The expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 in lung tissues were detected by Western blot. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression levels of IL-6, JAK2 and STAT3 in rat lung tissue. Results: The lung tissue structure of the model group was severely damaged compared to the control group, accompanied by a great many of inflammatory cell infiltration, goblet cell hyperplasia, subepithelial collagen fiber deposition and airway epithelial thickening were more obvious. The expressions of IL-6, IL- 23 and IL-17A in serum were significantly increased (P<0.01), the protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and the mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly increased (P<0.01);Compared with the model group, inflammatory cell infiltration, goblet cell proliferation, subepithelial collagen fiber deposition and airway epithelial thickening were significantly reduced in each administration group, and the expressions of IL-6, IL-23 and IL-17A in serum were significantly decreased (P< 0.01). The protein expression levels of JAK-2, P-JAK2, STAT3 and P-STAT3 and mRNA expression levels of IL-6, JAK2 and STAT3 in lung tissue were significantly decreased (P<0.01). Conclusion: Yanghe Pingchuan Granules can significantly alleviate airway remodeling in asthmatic rats, and its mechanism may be through inhibiting the IL-6/JAK2/STAT3 signal axis.

LINC00609 inhibits A549 cells progression through the regulation of miR-128-3p/RND3 axis

Background:Long-chain non-coding RNA(lncRNA)LINC00609 is a potential tumor suppressor,but the mechanism of action in non-small cell lung cancer(NSCLC)is yet to be understood.Objectives:The effects of LINC00609 on A549 cell proliferation,apoptosis,and cell cycle arrest were investigated.Methods:The LINC00609 levels in NSCLC and normal tissues were analyzed by bioinformatics.Expressions of LINC00609,miR-128-3p,and Rho family GTPase 3(RND3)in NSCLC cells(A549)were determined by qRT-PCR.Bioinformatics analysis predicted target genes and dual-luciferase reporter assays to ensure that LINC00609 targeted miR-128-3p and miR-128-3p targeted RND3.The proliferation of cells was determined using EDU and CCK-8.Flow cytometry was used to evaluate cell apoptosis rate and cell cycle.The western blotting assay identified proteins related to proliferation and apoptosis.Results:In NSCLC tissues,LINC00609 was expressed in low levels,while its high expression was associated with a higher survival rate.LINC00609 affected cell proliferation,apoptosis,cell cycle arrest,and expression of related proteins.Dual-luciferase reporter assay showed that LINC00609 binds specifically to miR-128-3p,and miR-128-3p binds to RND3.MiR-128-3p overexpression could neutralize the effects of LINC00609.A siRNA targeting RND3 could reverse the effect of the miR-128-3p inhibitor.Silencing RND3 resulted in a decrease in apoptosis rate and the number of cells in the S-phase and an increase in the number of cells in the G1-phase.Furthermore,phosphorylation levels of the AKT protein and mTOR protein,and Bcl2 expression,increased;however,the expression of RND3,Bax,and caspase3 decreased.Conclusions:LINC00609 regulated miR-128-3p/RND3 axis to modulate A549 cell proliferation,apoptosis,and cell cycle arrest.In the case of NSCLC,LINC00609 could be a potential target for therapy.

IMPROVED QUANTITATIVE FEEDBACK THEORY TECHNIQUE AND APPLICATION TO THREE-AXIS HYDRAULIC SIMULATOR

In order to meet tracking performance index of three-axis hydraulic simulator, based on classical quantitative feedback theory （QFT）, an improved QFT technique is used to synthesize controller of low gain and bandwidth. By choosing a special nominal plant, the improved method assigns relative magnitude and phase tracking error between system uncertainty and nominal control plant. Relative tracking error induced by system uncertainty is transformed into sensitivity problem and relative tracking error induced by nominal plant forms into a region on Nichols chart. The two constraints further form into a combined bound which is fit for magnitude and phase loop shaping. Because of leaving out pre-filter of classical QFT controller structure, tracking performance is enhanced greatly. Furthermore, a cascaded two-loop control strategy is proposed to heighten control effect. The improved technique＇s efficacy is validated by simulation and experiment results.

DEVELOPMENT OF NEW GENERATION THERMOMECHANICAL SIMULATOR-MULTI-AXIS RESTRAINT COMPRESSION(MARC-STRAIN^(TM))SYSTEM

Ultrafine grain size is often achieved by severe plastic deformation. A few techniques have been devel- oped to achieve severe plastic deformation,such as equal channel angular (ECA ) processing, torsion, and accumulative roll bonding (ARB) techmpues. This paper will introduce a moftiaxis deformation technique which can achieve essentially unlimited strain with constant deformation volume. The mul- tiaxis deformation can be fully restrained or unrestrained.The bulk volume of a multiaxis restraint compression specimen can be easily machined into mechanical testing specimens for mechanical property measurement and other studies.

青藤碱调节CXCR4-STAT3轴对卵巢癌A2780细胞增殖、迁移和血管生成拟态的影响

目的:探讨青藤碱(Sinomenine)对卵巢癌细胞增殖、迁移和血管生成拟态的影响及作用机制。方法:使用不同浓度(0、0.25、0.50、1.0、2.0、4.0、8.0 mmol/L)的青藤碱分别处理A2780细胞24、48 h, CCK-8法检测细胞存活率。将A2780细胞随机分为对照(Control)组、CXCR4激活剂基质细胞衍生因子-1(SDF-1)(SDF-1,100 ng/mL)组、CXCR4抑制剂普乐沙福(Plerixafor, 500 ng/mL)组、青藤碱(Sinomenine, 1.0 mmol/L)组、Sinomenine+SDF-1(1.0 mmol/L Sinomenine+100 ng/mL SDF-1)组,分别检测A2780细胞增殖、迁移与侵袭,体外血管生成拟态形成实验检测青藤碱对血管生成拟态的影响,Western blot法检测血管内皮生长因子(VEGF)、上皮细胞激酶(EphA2)、基质金属蛋白酶9(MMP-9)、MMP-2、CXC趋化因子受体4(CXCR4)、信号转导与转录激活因子3(STAT3)、磷酸化STAT3(p-STAT3)蛋白表达。结果:青藤碱可有效抑制A2780细胞增殖,且呈浓度依赖性;青藤碱可显著抑制A2780细胞迁移、侵袭及血管生成拟态形成,并下调血管生成拟态标志蛋白VEGF、EphA2、MMP-9、MMP-2表达,抑制CXCR4、p-STAT3表达(P<0.05),青藤碱的这一抑制作用可被CXCR4激活剂减弱。结论:青藤碱可能通过抑制CXCR4-STAT3轴,抑制卵巢癌细胞增殖、迁移、侵袭及血管生成拟态形成。

Fe-3%Si合金薄带连铸板热处理过程层状异构组织演变的相场模拟研究

本研究基于Fe-3%Si合金铸轧板材组织特征,构建了不同类型柱状晶/等轴晶层状异构组织相场模型,实现了界面曲率为驱动力的情况下层状异构组织的高温粗化过程模拟,量化分析了层状异构特征对铸轧组织演化过程的影响规律。研究表明,由于晶粒长径比对晶粒尖端曲率的影响,当初始状态下柱状晶长径比较高时,在界面曲率的驱动下最终会形成等轴化的多晶组织;反之则等轴化程度减小。明确了不同类型异构组织演化特征,相同退火时间下组织的等轴化程度受其层状异构特征的影响,这一现象的本质是等轴晶通过自身演化引起柱状晶两端曲率变化,诱发柱状晶间的相互“吞噬”并发生等轴化,柱状晶则在部分结构的组织中生长至带钢表面后停止生长,最终保持柱状特征。本研究进一步加深了对铸态薄带中初始凝固组织在后续热处理时演化过程的认识,对硅钢制备工艺优化具有重要的理论指导意义和实际应用价值。

纳米TiO_(2)对NH_(3)-H_(2)O-LiBr工质降膜吸收性能的影响

为了探讨纳米TiO_(2)对三元NH_(3)-H_(2)O-LiBr工质降膜吸收的影响,本文利用数值分析建立了三元工作流体薄膜吸收的连续方程、能量方程和组分质量平衡方程,采用Matlab软件进行编程和计算纳米流体的降膜吸收性能,将其与实验数据进行对比验证,并进一步分析了纳米TiO_(2)质量分数、初始氨浓度、初始温度、冷却水进口温度、吸收压力和下降薄膜管长度对薄膜吸收性能的影响。研究表明:添加纳米TiO_(2)可以增强降膜吸收的传质速率,主要原因为液膜中氨的扩散系数增加。当纳米TiO_(2)质量分数从0%增加到0.1%、0.3%和0.5%时,扩散系数分别增加了3.44倍、6.42倍和11.76倍。此外,增加初始氨浓度、降低初始温度、提高冷却水进口温度或降低吸收压力都可以提高最终溶液的饱和度。

A 3D Simulator for Autonomous Robotic Fish

This paper presents a 3D simulator used for studying the motion control and autonomous navigation of robotic fish. The simulator’s system structure and computation flow are presented. Simplified kinematics and hydrodynamics models for a virtual robotic fish are proposed. Many other object models are created for water, obstacles, sonar sensors and a swimming pool. Experimental results show that the simulator provides a realistic and convenient way to develop autonomous navigation algorithms for robotic fish.

SOCS1/JAK2/STAT3 axis regulates early brain injury induced by subarachnoid hemorrhage via inflammatory responses

The SOCS1/JAK2/STAT3 axis is strongly associated with tumor growth and progression,and participates in cytokine secretion in many diseases.However,the effects of the SOCS1/JAK2/STAT3 axis in experimental subarachnoid hemorrhage remain to be studied.A subarachnoid hemorrhage model was established in rats by infusing autologous blood into the optic chiasm pool.Some rats were first treated with JAK2/STAT3 small interfering RNA(Si-JAK2/Si-STAT3)or overexpression plasmids of JAK2/STAT3.In the brains of subarachnoid hemorrhage model rats,the expression levels of both JAK2 and STAT3 were upregulated and the expression of SOCS1 was downregulated,reaching a peak at 48 hours after injury.Simultaneously,the interactions between JAK2 and SOCS1 were reduced.In contrast,the interactions between JAK2 and STAT3 were markedly enhanced.Si-JAK2 and Si-STAT3 treatment alleviated cortical neuronal cell apoptosis and necrosis,destruction of the blood-brain barrier,brain edema,and cognitive functional impairment after subarachnoid hemorrhage.This was accompanied by decreased phosphorylation of JAK2 and STAT3 protein,decreased total levels of JAK2 and STAT3 protein,and increased SOCS1 protein expression.However,overexpression of JAK2 and STAT3 exerted opposite effects,aggravating subarachnoid hemorrhage-induced early brain injury.Si-JAK2 and Si-STAT3 inhibited M1-type microglial conversion and the release of pro-inflammatory factors(inducible nitric oxide synthase,interleukin-1β,and tumor necrosis factor-α)and increased the release of anti-inflammatory factors(arginase-1,interleukin-10,and interleukin-4).Furthermore,primary neurons stimulated with oxyhemoglobin were used to simulate subarachnoid hemorrhage in vitro,and the JAK2 inhibitor AG490 was used as an intervention.The in vitro results also suggested that neuronal protection is mediated by the inhibition of JAK2 and STAT3 expression.Together,our findings indicate that the SOCS1/JAK2/STAT3 axis contributes to early brain injury after subarachnoid hemorrhage both in vitro and in vivo by inducing inflammatory responses.This study was approved by the Animal Ethics Committee of Anhui Medical University and the First Affiliated Hospital of University of Science and Technology of China(approval No.LLSC-20180202)on March 1,2018.

Hydrogen-bond mediated and concentrate-dependent NaHCO_(3) crystal morphology in NaHCO3–Na2CO3 aqueous solution: Experiments and computer simulations

Adding Na_(2)CO_(3) to the NaHCO_(3) cooling crystallizer, using the common ion effect to promote crystallization and improve product morphology, is a new process recently proposed in the literature. However, the mechanism of the impact of Na_(2)CO_(3)on the crystal morphology is still indeterminate. In this work, the crystallization of NaHCO_(3)in water and Na_(2)CO_(3)–NaHCO_(3) aqueous solution was investigated by experiments and molecular dynamics simulations(MD). The crystallization results demonstrate that the morphology of NaHCO_(3) crystal changed gradually from needle-like to flake structure with the addition of Na_(2)CO_(3). The simulation results indicate that the layer docking model and the modified attachment energy formula without considering the roughness of crystal surface can obtain the crystal morphology in agreement with the experimental results, but the lower molecules of the crystal layer have to be fixed during MD. Thermodynamic calculation of the NaHCO_(3) crystallization process verifies that the common ion effect from Na^(+)and the ionization equilibrium transformation from CO_(3)^(2-) jointly promote the precipitation of NaHCO_(3) crystal. The radial distribution function analysis indicates that the oxygen atoms of Na_(2)CO_(3) formed strong hydrogen bonds with the hydrogen atoms of the(0 1 1) face, which weakened the hydration of water molecules at the crystal surface, resulting in a significant change in the attachment energy of this crystal surface. In addition, Na+and CO_(3)^(2-) are more likely to accumulate on the(011) face,resulting in the fastest growth rate on this crystal surface, which eventually leads to a change in crystal morphology from needle-like to flake-like.

Numerical and Experimental Study of the 3D Effect on Connecting Arm of Vertical Axis Tidal Current Turbine

Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF（User Defined Function） command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.

Evaluation of the Arctic Sea-Ice Simulation on SODA3 Datasets

This study evaluates the Arctic sea-ice simulation of the SODA3 dataset driven by different atmospheric forcing fields and explores the errors of the Arctic sea-ice simulation caused by the forcing field.We find that the SODA3 data driven by different forcing fields represent a significant systematical error in the simulation of Arctic sea-ice concentration,showing a low concentration of thick ice and a high concentration of thin ice.In terms of sea-ice extent,the SODA3 data from different versions well characterize the interannual variability and declining trend in the observed data,but they overestimate the overall Arctic sea-ice extent,which is related to excessive simulation of ice in the sea-ice margin.Compared to observations,all the chosen SODA3 reanalysis versions driven by different atmospheric forcing generally tend to underestimate the Arctic sea-ice thickness,especially for thick ice in the multi-year sea-ice regions.Inaccurate simulations of Arctic sea-ice transport may partly explain the error in SODA3 sea-ice thickness in multi-year sea-ice areas.The results of different SDOA3 versions differ greatly in the Beaufort Sea,the Fram Strait,and the Central Arctic Sea.The difference in sea-ice thickness among different SODA3 versions is primarily due to the thermodynamic contribution,which may come from the diversity of atmospheric forcing fields.Our work provides a reference for using SODA3 data to study Arctic sea ice.

定向凝固条件下Ti_(3)Al合金中梯度纳米结构的形成机制与力学行为——原子尺度研究

通过分子动力学(MD)模拟方法对Ti_(3)Al合金在定向凝固条件下的生长机理进行系统研究,并通过对比纳米晶(NG)、粗晶(CG)和梯度纳米晶(GNG)合金,研究Ti_(3)Al合金的结构力学性能。结果表明,在凝固过程中Ti_(3)Al相优先生长为等轴晶组织,随后逐渐演变为柱状粒,并最终形成梯度纳米晶结构。此时,晶粒在与凝固方向平行的方向优先生长。此外,研究还发现,相较于NG和CG结构,GNG结构定向凝固合金具有更高的抗拉强度和更好的延展性。GNG结构不仅有效抑制了小晶粒区域的应变局域化和晶粒生长,而且促进了较大晶粒区域的位错形成,从而获得更好的力学性能。

C_(2/3)经关节突经椎弓根螺钉固定的影像学测量及可行性分析

目的测量C_(2/3)经关节突经椎弓根螺钉相关影像学指标,并分析该置钉技术的可行性。方法收集120例全颈椎CT薄层扫描数据,其中男性75例,女性45例。设定C_(2/3)经关节突经椎弓根螺钉的进钉点,即进钉点在枢椎侧块的水平中线与中外1/3垂线交点处,螺钉自枢椎侧块穿C_(2/3)关节突关节、C_(3)侧块止于C_(3)椎弓根下缘。测量C_(2/3)经关节突经椎弓根螺钉相关影像学数据,包括C_(3)椎弓根宽度与高度,螺钉通道长度,内倾角度,头倾角度,最狭窄处宽度。并分析各项测量结果之间的关系。结果C_(3)椎弓根平均宽度5.48 mm,平均高度6.82 mm,螺钉通道平均长度18.68 mm,平均内倾角度20.46°,平均头倾角度50.1°,最狭窄处平均宽度2.80 mm。C_(3)椎弓根宽度与高度呈正相关(P=0.000),螺钉通道长度与C_(3)椎弓根宽度、高度呈正相关(P=0.000;P=0.000),螺钉通道最狭窄处宽度与C_(3)椎弓根宽度、高度呈正相关(P=0.000;P=0.000)。240例置钉测量数据中,如使用3.5 mm直径螺钉,均可完成置钉,C_(2/3)经关节突经椎弓根螺钉适用于所有患者。结论C_(2/3)经关节突经椎弓根螺钉在解剖学上是可行的,可作为上颈椎后路钉棒内固定补充的置钉技术。

2种黑豆球蛋白与矢车菊素-3-O-葡萄糖苷的相互作用研究

矢车菊素-3-O-葡萄糖苷(cyanidin-3-O-glucoside,C3G)在不同pH值环境中的主要存在形式不同,其抗氧化能力也有所差异。黑豆蛋白是一种常见的膳食蛋白,具有作为不稳定生物活性化合物载体的潜力,了解黑豆球蛋白与C3G的相互作用机制有利于它们在食品体系中的应用。通过多种光谱学分析和分子对接实验研究了pH值为2.0、5.0和7.0时黑豆β-伴大豆球蛋白(7S)和大豆球蛋白(11S)与C3G的相互作用及其对C3G氧化稳定性和抗氧化能力的影响。研究结果表明,pH值为2.0和5.0时,C3G与7S和11S结合不仅导致Tyr残基周围的疏水环境减少,极性增加,而且使7S和11S中α-螺旋增加,β-折叠比例下降。pH值为7.0时,C3G的存在使7S和11S中α-螺旋和β-折叠的占比呈增加趋势,但β-转角比例降低。此外,C3G与7S和11S结合是一个放热过程,在不同pH值条件下,C3G与7S和11S主要通过氢键和范德华力相互作用使7S和11S静态荧光猝灭。7S和11S均在pH值为7.0时对C3G亲和力最强。分子对接结果表明,7S上的GLU229、ARG356和PRO101残基,11S上的ARG161、VAL162、ILE171和THR176残基在与C3G结合中起关键作用。在不同pH值条件下,7S、11S与C3G结合后均显著增强了C3G的氧化稳定性和抗氧化能力。

Stiffness of Postural Alignment System Based on 3-Axis Actuators for Large Aircraft Components

Aircraft digital flexible assembly fixture and technologies are widely used in developed countries, while the traditional jig-based assembly mode is still used in China. The application study of aircraft digital flexible assembly system is just beginning in our country recently. To meet the requirements of automated posture alignment and join in digital assembly system for large aircraft components, a novel fitting fixture called 3-axis actuator is developed. On the basis of the actuators, three kinds of posture alignment system for large aircraft components are proposed, including the non-redundant system, the redundant actuating system, and the redundant leg system, and their constitutions and properties are introduced. Through deriving the feeding transmission stiffness model of single actuator and analyzing the inverse kinematics of these systems, the relationship between the external force and the changes of position and orientation of large aircraft component is obtained, and then the postural alignment stiffness models are established. With the method mentioned above, the postural alignment stiffness of three systems is computed by using the algebraic formulate, and the results show that redundant properties can increase system＇s postural alignment stiffness. As an example, a optimized layout of the assembly system for a given model of aircraft is developed, the results of application show that the layout has many advantages, such as high accuracy, stiffness, stability, reliability, efficiency and flexible, which can satisfy the requirement of aircraft digital assembly system well. The proposed study of postural alignment stiffness for different systems can supply the theoretic support for the optimization layout design of aircraft digital assembly system, and contribute to evaluate the system working performance of systems.

Dynamic analysis and simulation of four-axis forced synchronizing banana vibrating screen of variable linear trajectory

A new concept of banana vibrating screen which has the same effect as traditional banana vibrating screen in a new way was put forward.The dynamic model of vibrating screen was established and its working principle was analyzed when the action line of the exciting force did not act through the centroid of screen box.Moreover,the dynamic differential equations of centroid and screen surface were obtained.The motions of centroid and screen surface were simulated with actual parameters of the design example in Matlab/Simulink.The results show that not only the amplitude has a significant decrease from 9.38 to 4.10 mm,but also the throwing index and vibrating direction angle have a significant decrease from 10.49 to 4.59,and from 58.10° to 33.29°,respectively,along the screen surface,which indicates that motion characteristics of vibrating screen are consistent with those of traditional banana vibrating screen only by means of a single angle of screen surface.What's more,such banana vibrating screen of variable linear trajectory with greater processing capacity could be obtained by adjusting the relative position of force center and the centroid of screen box properly.