Research on the mechanical properties of membrane connections in tensioned membrane structures

Yingying Zhang,Qilin Zhang,Yang Li,Lu Chen 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.6

As an important part, the connections generally are important for the overall behavior of the structure and the strength and serviceability of the connection should be ensured. This paper presents the mechanical properties of membrane connections in tensioned membrane structure. First, the details of common connections used in the membrane structure are introduced. Then, the common connections including membrane seam, membrane-flexible edge connection and membrane-rigid edge connection are tested and the corresponding failure mechanisms are discussed. Finally, the effects of connection parameters on the connection strength are investigated and proper connection parameters are proposed. The strength reduction factors corresponding to different connection types are proposed, which can be references for the design and analysis of membrane structures.

Melatonin prevents lung injury by regulating apelin 13 to improve mitochondrial dysfunction

Lu Zhang,Fangli Liu,Xiaomin Su,Yue Li,Yining Wang,Ruonan Fang,Yingying Guo,Tongzhu Jin,Huitong Shan,Xiaoguang Zhao,Rui Yang,Hongli Shan,Haihai Liang 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-

Pulmonary fibrosis is a progressive disease characterized by epithelial cell damage, fibroblast proliferation, excessive extracellular matrix (ECM) deposition, and lung tissue scarring. Melatonin, a hormone produced by the pineal gland, plays an important role in multiple physiological and pathological responses in organisms. However, the function of melatonin in the development of bleomycin-induced pulmonary injury is poorly understood. In the present study, we found that melatonin significantly decreased mortality and restored the function of the alveolar epithelium in bleomycin-treated mice. However, pulmonary function mainly depends on type II alveolar epithelial cells (AECIIs) and is linked to mitochondrial integrity. We also found that melatonin reduced the production of reactive oxygen species (ROS) and prevented apoptosis and senescence in AECIIs. Luzindole, a nonselective melatonin receptor antagonist, blocked the protective action of melatonin. Interestingly, we found that the expression of apelin 13 was significantly downregulated in vitro and in vivo and that this downregulation was reversed by melatonin. Furthermore, ML221, an apelin inhibitor, disrupted the beneficial effects of melatonin on alveolar epithelial cells. Taken together, these results suggest that melatonin alleviates lung injury through regulating apelin 13 to improve mitochondrial dysfunction in the process of bleomycin-induced pulmonary injury.

Research on the mechanical properties of membrane connections in tensioned membrane structures

Zhang, Yingying,Zhang, Qilin,Li, Yang,Chen, Lu Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.6

As an important part, the connections generally are important for the overall behavior of the structure and the strength and serviceability of the connection should be ensured. This paper presents the mechanical properties of membrane connections in tensioned membrane structure. First, the details of common connections used in the membrane structure are introduced. Then, the common connections including membrane seam, membrane-flexible edge connection and membrane-rigid edge connection are tested and the corresponding failure mechanisms are discussed. Finally, the effects of connection parameters on the connection strength are investigated and proper connection parameters are proposed. The strength reduction factors corresponding to different connection types are proposed, which can be references for the design and analysis of membrane structures.

Experimental study of buckling-restrained brace with longitudinally profiled steel core

Junkai Lu,Yong Ding,Bin Wu,Yingying Li,Jiaxin Zhang 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.6

A new type of buckling-restrained braces (BRBs) with a longitudinally profiled steel plate working as the core (LPBRB) is proposed and experimentally investigated. Different from conventional BRBs with a constant thickness core, both stiffness and strength of the longitudinally profiled steel core along its longitudinal direction can change through itself variable thickness, thus the construction of LPBRB saves material and reduces the processing cost. Four full-scale component tests were conducted under quasi-static cyclic loading to evaluate the seismic performance of LPBRB. Three stiffening methods were used to improve the fatigue performance of LPBRBs, which were bolt-assembled T-shaped stiffening ribs, partly-welded stiffening ribs and stiffening segment without rib. The experimental results showed LPBRB specimens displayed stable hysteretic behavior and satisfactory seismic property. There was no instability or rupture until the axial ductility ratio achieved 11.0. Failure modes included the out-of-plane buckling of the stiffening part outside the restraining member and core plate fatigue fracture around the longitudinally profiled segment. The effect of the stiffening methods on the fatigue performance is discussed. The critical buckling load of longitudinally profiled segment is derived using Euler theory. The local bulging behavior of the outer steel tube is analyzed with an equivalent beam model. The design recommendations for LPBRB are presented finally.

Effects of ball milling on structural changes and hydrolysis of lignocellulosic biomass in liquid hot-water compressed carbon dioxide

Houfang Lu,Xiaoliang Yuan,Shijie Liu,Guangrong Feng,Yingying Liu,Yongdan Li,Bin Liang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7

Mechanical activation is an effective method for destroying the crystalline structure. Biomass, especially its hemicellulose, can be degraded in the green solvent of liquid hot-water compressed carbon dioxide. To improve the degradation of crystalline cellulose in liquid hot-water compressed carbon dioxide, pretreatment of camphorwood sawdust by mechanical activation with a stirring ball mill was studied. Ball milling parameters and their effects on structure were determined by SEM, XRD and FT-IR. The influence of milling parameters on cellulose conversion can be ranked as follows: ball milling speed>activation time>the mass ratio of ball to biomass. The optimum milling condition was obtained at ball milling speed of 450 rpm and mass ratio of 30 : 1 of ball to biomass for 2 h. In this condition, cellulose crystallinity of sawdust decreased from 60.93% to 21.40%. The cellulose conversion was 37.8%, which was nearly four times of raw material (10.2%). The glucose yield in the hydrolysate was 1.49 g·L−1, which was nearly three times of that of raw material. It showed mechanical activation can destroy the crystalline structure of cellulose to promote degradation and the damage of lignocellulosic internal structure caused by ball milling is irreversible.

Influence of Inorganic Ions and pH on the Photodegradation of 1-Methylimidazole-2- thiol with TiO2 Photocatalyst Based on Magnetic Multi-walled Carbon Nanotubes

Yinhua Jiang,Yingying Luo,Ziyang Lu,Pengwei Huo,Weinan Xing,Ming He,Jiqin Li,Yongsheng Yan 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.1

1-Methylimidazole-2-thiol, as a kind of mercaptans, is a typical organic pollutant which has not been efficiently removed. In this study, titanium dioxide (TiO 2 ) photocatalyst based on magnetic multi-walled carbon nanotubes (MWCNTs) was synthesized via hydrothermal and sol-gel methods. The as-prepared photocatalyst was extensively characterized by X-ray diffraction (XRD), X-ray energy diffraction spectrum (EDS), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectra, UV-Vis diffuse reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM). This photocatalyst of TiO 2 /Fe 3 O 4 /MWCNTs was proved to exhibit high photocatalytic efficiency and the photodegradation rate could reach nearly 82.7% for the degradation of 1-methylimidazole-2-thiol under ultraviolet irradiation. In addition, the results demonstrated that inorganic ions had a negative impact on photodegradation of 1-methylimidazole-2-thiol to varying degrees. Moreover, pH had a great and complex effect on photocatalytic degradation of 1-methylimidazole-2-thiol under ultraviolet irradiation.

Clinical effectiveness of different types of bone-anchored maxillary protraction devices for skeletal Class III malocclusion: Systematic review and network meta-analysis

Wang, Jiangwei,Yang, Yingying,Wang, Yingxue,Zhang, Lu,Ji, Wei,Hong, Zheng,Zhang, Linkun The Korean Association Of Orthodontists 2022 대한치과교정학회지 Vol.52 No.5

Objective: This study aimed to estimate the clinical effects of different types of bone-anchored maxillary protraction devices by using a network meta-analysis. Methods: We searched seven databases for randomized and controlled clinical trials that compared bone-anchored maxillary protraction with tooth-anchored maxillary protraction interventions or untreated groups up to May 2021. After literature selection, data extraction, and quality assessment, we calculated the mean differences, 95% confidence intervals, and surface under the cumulative ranking scores of eleven indicators. Statistical analysis was performed using R statistical software with the GeMTC package based on the Bayesian framework. Results: Six interventions and 667 patients were involved in 18 studies. In comparison with the tooth-anchored groups, the bone-anchored groups showed significantly more increases in Sella-Nasion-Subspinale (°), Subspinale-Nasion-Supramentale(°) and significantly fewer increases in mandibular plane angle and the labial proclination angle of upper incisors. In comparison with the control group, Sella-Nasion-Supramentale(°) decreased without any statistical significance in all treated groups. IMPA (angle of lower incisors and mandibular plane) decreased in groups with facemasks and increased in other groups. Conclusions: Bone-anchored maxillary protraction can promote greater maxillary forward movement and correct the Class III intermaxillary relationship better, in addition to showing less clockwise rotation of mandible and labial proclination of upper incisors. However, strengthening anchorage could not inhibit mandibular growth better and the lingual inclination of lower incisors caused by the treatment is related to the use of a facemask.

Simultaneous desulfurization and denitrogenation of model fuels by polyethylene glycol-modified resorcinol/formaldehyde resin-derived carbon spheres

Jie Wen,Dongdong Zhao,Yingying Lu,Jing Huang,Yanping Li,Hui Zhang,Airong Li 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.7

A series of resorcinol/formaldehyde (RF) resin-derived carbon spheres modified by polyethylene glycol (PEG) were prepared. The effects of PEG addition time during hydrothermal treatment and molecular weight on the pore structure, surface acidic groups, particle size, and adsorption performances of the obtained spherical activated carbons were investigated. Two types of model fuel containing indole, quinoline, and dibenzothiophene (DBT) as target adsorbates were prepared to evaluate the adsorption performances of the spheres, which increased in the order of DBT<quinoline<indole. Hydrogen bonding may be critical in the removal of indole. Both the surface area and oxygen- containing functional groups influenced the adsorption capacity, with the latter significantly influenced by PEG addition time. PEG addition during the RF resin cross-linking stage sharply reduced the total concentration of acidic groups on the carbon sphere surfaces. The adsorption thermodynamics and kinetics of nitrogen and sulfur compounds were also investigated. The adsorption isotherms of all S/N species were of the Freundlich type at 25 oC. The pseudo-second-order rate equation well described the adsorption kinetics. Both external diffusion and intra-particle diffusion controlled the rate of adsorption.

Ferulic acid exhibits anti-inflammatory effects by inducing autophagy and blocking NLRP3 inflammasome activation

Liu Yongjuan,Shi Lu,Qiu Wenhong,Shi Yingying 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.4

Background Inflammation is involved in the healing process; however, when inflammation is overactivated, multiple diseases can occur. The continued discovery of new anti-inflammatory drugs is crucial in the treatment of inflammation-linked diseases. Objectives Ferulic acid (FA), a precursor necessary for lignan synthesis, is widely distributed in plant-based whole foods and is a strong antioxidant. However, the effect of FA on the expression level of inflammatory factors in macrophages has not been fully clarified. The current study aimed to explore the anti-inflammatory effect and mechanism of ferulic acid. Results The results showed that THP-1 cells were induced to differentiate into macrophages by Phorbol-12-myristate- 13-acetate (PMA), and THP-1-derived macrophages were stimulated by LPS to establish an inflammatory cell model. Compared with the control group, low (5 μmol·mL −1 ), medium (10 μmol·mL −1 ), and high (20 μmol·mL −1 ) concentration ferulic acid groups have decreased cell viability and increased apoptosis rate in a dose-dependent manner. FA reduced the transcriptional levels of Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α). Importantly, FAinduced autophagy and inhibited NLRP3 inflammasome activation. 3-MA (a widely used autophagy inhibitor) enhanced the secretion of TNF-α, IL-6 and IL-1β. Moreover, autophagy inhibition by 3-MA resulted in increased proteins expression associated with NLRP3 inflammasome signaling pathway. Besides, the inhibition of inflammasome activation by MCC950 reduced the expression of TNF-α, IL-6 and IL-1β. Conclusion It is concluded that FA enhanced autophagy, inhibited the activation of NLRP3 inflammasome and reduced the expression and release of inflammatory factors.

Influence of Inorganic Ions and pH on the Photodegradation of 1-Methylimidazole-2-thiol with TiO₂ Photocatalyst Based on Magnetic Multi-walled Carbon Nanotubes

Jiang, Yinhua,Luo, Yingying,Lu, Ziyang,Huo, Pengwei,Xing, Weinan,He, Ming,Li, Jiqin,Yan, Yongsheng Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.1

1-Methylimidazole-2-thiol, as a kind of mercaptans, is a typical organic pollutant which has not been efficiently removed. In this study, titanium dioxide ($TiO_2$) photocatalyst based on magnetic multi-walled carbon nanotubes (MWCNTs) was synthesized via hydrothermal and sol-gel methods. The as-prepared photocatalyst was extensively characterized by X-ray diffraction (XRD), X-ray energy diffraction spectrum (EDS), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectra, UV-Vis diffuse reflectance spectra (UV-vis DRS) and vibrating sample magnetometer (VSM). This photocatalyst of $TiO_2$/$Fe_3O_4$/MWCNTs was proved to exhibit high photocatalytic efficiency and the photodegradation rate could reach nearly 82.7% for the degradation of 1-methylimidazole-2-thiol under ultraviolet irradiation. In addition, the results demonstrated that inorganic ions had a negative impact on photodegradation of 1-methylimidazole-2-thiol to varying degrees. Moreover, pH had a great and complex effect on photocatalytic degradation of 1-methylimidazole-2-thiol under ultraviolet irradiation.