Dynamic Characteristics and Responses of Tall Building Structures with Double Negative Stiffness Damped Outriggers

Sun, Feifei,Duan, Ningling,Wang, Meng,Yang, Jiaqi Council on Tall Building and Urban Habitat Korea 2021 International journal of high-rise buildings Vol.10 No.3

Dynamic characteristics of tall building structures with double negative stiffness damped outriggers (2NSDO) are parametrically studied using the theoretical formula. Compared with one negative stiffness damped outrigger (1NSDO), 2NSDO can achieve a similar maximal modal damping ratio with a smaller negative stiffness ratio. Besides, the 2NSDO can improve the maximum achievable damping ratio to about 30% with less consumption of an outrigger damping coefficient compared with the double conventional damped outriggers (2CDO). Besides, the responses of structures with 2NSDO under fluctuating wind load are investigated by time-history analysis. Numerical results show that the 2NSDO is effective in reducing structural acceleration under fluctuating wind load, being more efficient than 1NSDO.

Cloning and Sequence Analysis of Nitrate Reductase Gene cDNA Fragments from Non-Heading Chinese Cabbage

Feifei Sun,Xilin Hou,Ying Li 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Lyapunov Based Robust Control for Tracking Control of Lower Limb Rehabilitation Robot with Uncertainty

Feifei Qin,Han Zhao,Shengchao Zhen,Hao Sun,Yan Zhang 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.1

This study designs a control of two-degree of freedom lower limb rehabilitation robot (LLRR) for the patient who needs the proper physical therapy after a spinal cord injury (SCI), stroke, or a surgical operation. The robot manipulator can perform specified passive exercises as well as copy exercise motions and perform them without the physiotherapist. Specifically, the uncertainties including the model uncertainty, initial condition deviation and the external disturbance are also considered. Firstly, a unilateral man-robot dynamical model is proposed based on Lagrange method. Then, we propose a Lyapunov based robust control to suppress the effect of uncertainties. The control algorithm consists of a PD feedback component and a piecewise function component. Theoretical analysis is provided to demonstrate that the controller can guarantee the uniform boundedness and uniform ultimate boundedness of the system. Moreover, the joint angle trajectory of a healthy person is explicitly obtained by the experimental platform and used as the pre-specified trajectory of the LLRR. Finally, numerical simulation is presented to illustrate the effectiveness and the trajectory-tracking control performance of the control.

Interaction of the Lysophospholipase PNPLA7 with Lipid Droplets through the Catalytic Region

Chang, Pingan,Sun, Tengteng,Heier, Christoph,Gao, Hao,Xu, Hongmei,Huang, Feifei Korean Society for Molecular and Cellular Biology 2020 Molecules and cells Vol.43 No.3

Mammalian patatin-like phospholipase domain containing proteins (PNPLAs) play critical roles in triglyceride hydrolysis, phospholipids metabolism, and lipid droplet (LD) homeostasis. PNPLA7 is a lysophosphatidylcholine hydrolase anchored on the endoplasmic reticulum which associates with LDs through its catalytic region (PNPLA7-C) in response to increased cyclic nucleotide levels. However, the interaction of PNPLA7 with LDs through its catalytic region is unknown. Herein, we demonstrate that PNPLA7-C localizes to the mature LDs ex vivo and also colocalizes with pre-existing LDs. Localization of PNPLA7-C with LDs induces LDs clustering via non-enzymatic intermolecular associations, while PNPLA7 alone does not induce LD clustering. Residues 742-1016 contains four putative transmembrane domains which act as a LD targeting motif and are required for the localization of PNPLA7-C to LDs. Furthermore, the N-terminal flanking region of the LD targeting motif, residues 681-741, contributes to the LD targeting, whereas the C-terminal flanking region (1169-1326) has an anti-LD targeting effect. Interestingly, the LD targeting motif does not exhibit lysophosphatidylcholine hydrolase activity even though it associates with LDs phospholipid membranes. These findings characterize the specific functional domains of PNPLA7 mediating subcellular positioning and interactions with LDs, as wells as providing critical insights into the structure of this evolutionarily conserved phospholipid-metabolizing enzyme family.

LncRNA CRNDE Promotes the Progression of B-cell Precursor Acute Lymphoblastic Leukemia by Targeting the miR-345-5p/CREB Axis

Weimin Wang,Feifei Wu,Ping Ma,Silin Gan,Xue Li,Li Chen,Ling Sun,Hui Sun,Zhongxing Jiang,Feng Guo 한국분자세포생물학회 2020 Molecules and cells Vol.43 No.8

The imbalance between the proliferation and apoptosis of B-cell precursors is an important contributor to the pathogenesis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), while its specific regulatory mechanism remains perplexing. This study aimed to expound the underlying mechanism of the proliferation and apoptosis of BCP-ALL cells from the perspective of non-coding RNA. In this study, long non-coding RNA colorectal neoplasia differentially expressed (LncRNA CRNDE) was upregulated in the bone marrow of BCP-ALL patients and BCP-ALL cell lines (NALM-6 and RS4;11). Functionally, LncRNA CRNDE knockdown restrained cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. The subsequent investigation confirmed that LncRNA CRNDE bound to miR-345-5p and negatively regulated miR-345-5p expression. The overexpression of miR-345-5p suppressed cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. Further experiments revealed that miR-345-5p downregulated cyclic AMP response element-binding protein (CREB) expression by targeting its mRNA directly. CREB overexpression reversed the effect of miR-345-5p mimic on cell proliferation and apoptosis in NALM-6 and RS4;11 cells. Finally, in vivo experiments showed that LncRNA CRNDE knockdown prolonged the survival of mice xenotransplanted with NALM-6 cells. In conclusion, LncRNA CRNDE upregulated CREB expression by suppressing miR-345-5p, thus promoting cell proliferation and reducing cell apoptosis in BCP-ALL.

Structural Shear Wall Systems with Metal Energy Dissipation Mechanism

Li, Guoqiang,Sun, Feifei,Pang, Mengde,Liu, Wenyang,Wang, Haijiang Council on Tall Building and Urban Habitat Korea 2016 International journal of high-rise buildings Vol.5 No.3

Shear wall structures have been widely used in high-rise buildings during the past decades, mainly due to their good overall performance, large lateral stiffness, and high load-carrying capacity. However, traditional reinforced concrete wall structures are prone to brittle failure under seismic actions. In order to improve the seismic behavior of traditional shear walls, this paper presents three different metal energy-dissipation shear wall systems, including coupled shear wall with energy-dissipating steel link beams, frame with buckling-restrained steel plate shear wall structure, and coupled shear wall with buckling-restrained steel plate shear wall. Constructional details, experimental studies, and calculation analyses are also introduced in this paper.

Difference in Lake Water Area Derived from Different Resolution Imagery

Rong Xu,Zengxiang Zhang,Feifei Sun,Qingke Wen,Fang Liu 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.4

In order to study the difference in lake water area derived from satellite images with different resolutions, the lake distribution maps with 30 m, 250 m and 500 m spatial resolution were derived from HJ-1A/B and MODIS data acquired in the same period. It is showed that the area estimates derived from both 250 m MODIS and 500 m MODIS have strong correlations with those derived from HJ-1A/B data for lakes with area larger than 10 km2. And 500 m MODIS data can get nearly the same estimates as 250 m MODIS data. For further analysis of the difference in lake water area, those lakes were divided into three groups according to the shape indices of lake water body, which were calculated with the results extracted from HJ-1A/B imagery. Taking HJ-1A/B lake maps as reference, it is found that the error of estimates from MODIS data increases when the lake area decreases and the shape complexity increases.

Cyclic behavior of steel beam-concrete wall connections with embedded steel columns (I): Experimental study

Guo-Qiang Li,Fulin Gu,Jian Jiang,Feifei Sun 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.4

This paper experimentally studies the cyclic behavior of hybrid connections between steel coupling beams and concrete shear walls with embedded steel columns. Four beam-to-wall connection specimens with short and long embedded steel columns are tested under monotonic and cyclic loads, respectively. The influence of embedment length of columns on the failure mode and performance of connections is investigated. The results show that the length of embedded steel columns has significant effect on the failure mode of connections. A connection with a long embedded column has a better stiffness, loadbearing capacity and ductility than that of a short embedded column. The former fails due to the shear yielding of column web in the joint panel, while failure of the latter is initiated by the yielding of horizontal reinforcement in the wall due to the rigid rotation of the column. It is recommended that embedded steel columns should be placed along the entire height of shear walls to facilitate construction and enhance the ductility.

Evaluation and Comparation of a Novel Surgical Technique and Hemivertebra Resection to the Correction of Congenital Cervical Scoliosis in Lower Cervical and Cervicothoracic Spine

Shuo Cao,Xin Chen,Shengfa Pan,Yinze Diao,Yanbin Zhao,Tian Xia,Weishi Li,Feifei Zhou,Yu Sun 대한척추신경외과학회 2022 Neurospine Vol.19 No.4

Objective: To report concave-side distraction technique to treat congenital cervical scoliosis in lower cervical and cervicothoracic spine. To evaluate and compare clinical and radiographic results of this procedure with classic hemivertebra resection procedure. Methods: This study reviewed 29 patients in last 13 years. These patients were divided into convex-side resection group (group R) and concave-side distraction group (group D). Radiographic assessment was based on parameter changes preoperatively, postoperatively and at last follow-up. Demographic data, surgical data and complications were also evaluated and compared between the 2 groups. Results: In group R, mean age was 8.9 ± 3.3 years and follow-up was 46 ± 18 months. Operation time and blood loss averaged 500 ± 100 minutes, 703 ± 367 mL. In group D, mean age was 9.9 ± 2.8 years and follow-up was 34 ± 14 months. Operation time and blood loss averaged 501 ± 112 minutes, 374 ± 181 mL. Structural Cobb angle was corrected from 29.4° ± 12.5° to 5.3° (2.1°–18.1°) (p = 0.001) and 33.7° ± 14.1° to 12.8° ± 11.4° (p < 0.001) in groups R and D. Compensatory Cobb angle had a spontaneous correction rate of 59.6% (40.0%–80.8%) and 59.7% ± 23.0% in groups R and D. Mandibular incline, clavicle angle and spine coronal balance were significantly improved at last follow-up in both groups. All correction rates were not statistically different between groups. However, group D had significant less blood loss (p < 0.001) and operation time (p = 0.004) per vertebra than group R. Seven patients developed C5 nerve root palsy and recovered by 6 months of follow-up. Conclusion: Both surgical procedures are safe and effective in correcting congenital cervical scoliosis. But concave-side distraction technique has less blood loss and time-consuming during surgery, which provides a better option for the treatment of congenital cervical scoliosis.