Synthesis of novel oleanolic acid and ursolic acid in C-28 position derivatives as potential anticancer agents

Tian Tian,Xinyu Liu,이응석,Jingyang Sun,Zhonghua Feng,Long-Xuan Zhao,Chunhui Zhao 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.4

A series of nitrogen-containing derivatives ofoleanolic acid and ursolic acid were prepared by a modificationat C-28 position via esterification with 2-hydroxyaceticacid followed by amidation with amines, such aspiperazine, N-methylpiperazine, and alkane-1, 2-diamines,alkane-1, 4-diamines, alkane-1, 6-diamines. In vitroantiproliferative activities of the compounds preparedtowards MCF-7, Hela and A549 cell lines were evaluatedby a MTT method to show that OA-5a, OA-5b, OA-5c andUA-5a showed somewhat improved antiproliferativeactivities against MCF-7, Hela and A549 cells comparingto that of the positive control, gefitinib.

Multi-objective Optimization of a Hydrogen-Battery Hybrid Storage System for Offshore Wind Farm Using MOPSO

Tian Tian,Ma Zetao,Cui Qiong,Shu Jie,Tan Lei,Wang Hao 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

Recently, offshore wind farms (OWFs) are gaining more and more attention for its high efficiency and yearly energy production capacity. However, the power generated by OWFs has the drawbacks of intermittence and fluctuation, leading to the deterioration of electricity grid stability and wind curtailment. Energy storage is one of the most important solutions to smooth the wind power and capture its surplus. In this paper, we provide a multi-objective optimization approach that combines multi-objective particle swarm optimization and rule-based energy management strategy for an on-gird offshore wind-hydrogen-battery system to simultaneously address the economic (Eco), the qualified rate of smoothing offshore wind power fluctuations (QRS), and the rate of offshore wind power curtailment (ROC). Results revealed that ROC and Eco, QRS and Eco are negatively correlated, but ROC and QRS are positively correlated. The hybrid storage system is more conducive to improve QRS and reduce ROC. Comparing with other three systems, the improvement range for ROC is between 13.6 and 46% when QRS is 100%. In addition, battery storage improves QRS by 2.6%, hydrogen storage deteriorates Eco by 86.8% and improve ROC by 38.5%, the change of ROC and QRS brings by transmission project are close to 100% and 4.4%.

Seismic behavior of steel tube reinforced concrete bridge columns

Tian Tian,Wenliang Qiu,Zhe Zhang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.1

This paper reports an experimental study that was accomplished to assess the seismic behavior of steel tube reinforced concrete bridge columns (SBCs). The motivation of this study was to verify a supposition that the core steel tube may be terminated at a rational position in the column to minimize the material cost while maintaining the seismic behavior of this composite column. Four SBC specimens were tested under combined constant axial load and cyclic reversed lateral loads. The unique variable in the test matrix was the core steel tube embedment length, which ranged from 1/3 to 3/3 of the column effective height. It is observed that SBCs showed two distinctly different failure patterns, namely brittle shear failure and ductile flexural failure. Tests results indicate that the hysteretic responses of SBCs were susceptible to the core steel tube embedment length. With the increase of this structural parameter, the lateral strength of SBC was progressively improved; the deformability and ductility, however, exhibited a tendency of first increase and then decrease. It is also found that in addition to maintained the rate of stiffness degradation and cumulative energy dissipation basically unchanged, both the ductility and deformability of SBC were significantly improved when the core steel tube was terminated at the mid-height of the column, and these were the most unexpected benefits accompanied with material cost reduction.

Microfluidic Devices for Eye Irritation Tests of Cosmetics and Cosmetic Ingredients

Tian Tian,조수진,이석우 한국바이오칩학회 2019 BioChip Journal Vol.13 No.2

In this paper, we describe the development and application of a simple microfluidic device for in vitro irritation tests of cosmetics. The device was fabricated with a three-compartment diffusion system to mimic a hen’s egg test-chorioallantoic membrane (HET-CAM) system. Human umbilical vein endothelial cells were cultured in the three compartments, and the tested substances were injected into the compartment, and then were drawn through the small microfluidic channels. The mortalities of cells in each compartment were monitored using a fluorescent microscope. The TS (toxicity score) values were evaluated on the basis of the mortalities of cells as a function of time when the cells were exposed to the test substances. Four kinds of cosmetic materials were tested with the microfluidic system, and the results were compared with IS (irritation score) values of a HET-CAM test to validate the in vitro irritation test system. The method developed in this study could be used for evaluation of the ocular toxicity of cosmetic ingredients, and could be widely used as an alternative test for cosmetic and medical tests or for the development of new medicines.

Family History and Stroke Risk in China: Evidence from a Large Cohort Study

Tian Tian,Guangfu Jin,Canqing Yu,Jun Lv,Yu Guo,Zheng Bian,Ling Yang,Yiping Chen,Hongbing Shen,Zhengming Chen,Zhibin Hu,Liming Li 대한뇌졸중학회 2017 Journal of stroke Vol.19 No.2

Background and Purpose Large cohort studies on relationship between family history of stroke(FHS) and stroke risk are lacking in Asians. We aimed to systematically evaluate the association ofFHS with stroke risk in a cohort study of 0.5 million Chinese adults. Methods Information about FHS was self-reported. The median follow-up time was 7.16 years andthe end-point of follow-up was incident stroke, which was entered directly into the China KadoorieBiobank system. Multivariate analyses were performed with Cox proportional hazards model, andinteraction analyses were carried using likelihood-ratio tests. Results Compared with participants without FHS, the hazard ratio (HR) (95% confidence interval,CI) of stroke for participants with FHS was 1.50 (1.46-1.55). The HRs increased with the number offirst degree relatives with stroke (HRs=1.41, 1.98 and 2.47 for 1, 2 and ≥3 relatives, respectively,Ptrend <0.001). The HRs were 1.57 (95% CI: 1.50-1.66) and 1.49 (95% CI: 1.45-1.54) for siblinghistory and parental history, respectively. Similar associations with offspring stroke risk wereobserved between paternal history (HR=1.48, 95% CI: 1.43-1.54) and maternal history (HR=1.49,95% CI: 1.43-1.55). Moreover, significant interactions were detected between FHS and health-riskbehaviors (tobacco smoking and alcohol drinking). Conclusions FHS is an independent risk factor for stroke in Chinese. The more first degree relativesare affected by stroke, the higher are individuals’ risk of suffering from stroke. The management ofthe health-risk behaviors for reducing stroke should be highlighted, especially for the individualswith FHS.

New Criteria for Finite-Time Stability of Linear Time-Delay Systems

Tiantian Huang,Yuangong Sun 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

In this paper, we discuss the finite-time stability of linear time-delay systems. Firstly, by constructing a time-varying quadratic Lyapunov function, we establish a new finite-time stability criterion for the general linear time-delay system. Then, explicit conditions for finite-time stability of positive linear time-delay system are proposed in terms of linear inequalities by introducing a time-varying linear copositive Lyapunov function. Finally, a numerical example is given to demonstrate the effectiveness of the method.

Energy Saving Elevator Group Supervisory Control System with Idle Cage Assignment using Genetic Network Programming

Tiantian Zhang,Shingo Mabu,Lu Yu,Jin Zhou,Xianchao Zhang,Kotaro Hirasawa 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

Elevator group supervisory control system (EGSCS) is designed for managing the elevator movement to transport passengers in buildings efficiently. So far, Genetic Network Programming which is a kind of evolutionary computation with a graph structure has been applied to such complex systems like EGSCS. On the other hand, in order to reduce the energy consumption in EGSCS, some studies have been done in our previous research, but when some cages become idle, the cages are supposed to go back to the first floor, which consumes much energy. In this paper, we use an Idle Cage Assignment Algorithm to dispatch the idle cages in a light traffic mode in order to reduce the energy consumption of EGSCS.

Comparison of Dynamic Sorption and Hygroexpansion of Wood by Different Cyclic Hygrothermal Changing Effects

Tiantian Yang,Erni Ma 한국목재공학회 2016 목재공학 Vol.44 No.2

To investigate the dynamic sorptive and hygroexpansive behaviors of wood by different cyclic hygrothermal changing effects, poplar (populus euramericana Cv.) specimens, were exposed to dynamic sorption processes where relative humidity (RH) and temperature changed simultaneously in sinusoidal waves at 75-45% and 5-35℃ (condition A) and where RH changed sinusoidally at 75-45% but temperature was controlled at 20℃ (condition B), both for three cyclic periods of 1, 6, and 24 h. Moisture and dimensional changes measured during the cycling gave the following results: Moisture and transverse dimensional changes were generally sinusoidal. Moisture and dimensional amplitude increased with increasing cyclic period but all were lower for thicker specimens. The amplitude ratio of condition A to condition B ranged from 1.0 to 1.6 with the maximum value of 1.57 occurring at the shortest cyclic period, not as much as expected. T/R increased as cyclic period increased or specimen thickness decreased. T/R from condition B was weaker than that from condition A. Sorption and swelling hysteresis existed in both conditions. Sorption hysteresis was negatively related to cyclic period but in positive correlation with specimen thickness. Sorption hysteresis was found more obvious in condition B, while moisture sorption coefficient and humidity expansion coefficient showed the opposite results.

The mechanism of photocurrent enhancement of ZnO ultraviolet photodetector by reduced graphene oxide

Tiantian Yang,Bin Sun,Lei Ni,Xing Wei,Tingting Guo,Zhemin Shi,Fei Han,Li Duan 한국물리학회 2018 Current Applied Physics Vol.18 No.8

An ultraviolet (UV) photodetector based on ZnO-reduced graphene oxide (ZnO-rGO) composites have been successfully fabricated. A pure ZnO photodetector was also fabricated by similar method. In comparison with the pure ZnO UV photodetector, the ZnO-rGO photodetector exhibits a much larger photocurrent and a better lightto- dark-current-ratio. The mechanism of photocurrent enhancement was investigated using I-V characteristics, photoluminescence (PL) spectra, transmittance spectra and time-dependent photocurrent analysis. Results show that the photocurrent enhancement of the ultraviolet photodetector is due to the improvement of the carrier lifetime, because the carrier recombination of ZnO were reduced by rGO. It provides a potential way to fabricate high-response UV photodetectors.

Dimensional Responses of Wood Under Cyclical Changing Temperature at Constant Relative Humidity

Tiantian Yang,Erni Ma,Yi Shi 한국목재공학회 2015 목재공학 Vol.43 No.5

To investigate dimensional responses of wood under dynamic temperature condition, poplar (populous euramericana Cv.) specimens, 20 mm in radial (R) and tangential (T) directions with two thicknesses of 4 and 10 mm along the grain, were exposed to cyclic temperature changes in square wave between 25℃ and 40℃ at 60% relative humidity (RH) for three different cycling periods of 6 h, 12 h and 24 h. R and T dimensional changes measured during the cycling gave the following results: 1) Transverse dimensional changes of the specimens were generally square but at an opposite phase and lagged behind the imposed temperature changes. The phase lag was inversely correlated with cycling period, but positively related to specimen thickness, while the response amplitude was directly proportional to cycling period, but in a negative correlation with specimen thickness. 2) The specimens showed swelling hysteresis behavior. The heat shrinkage coefficient (HSC) became greater as cycling period increased or specimen thickness decreased. 3) Dimensional changes of the specimens produced deformation accumulation during repeated adsorption and desorption. The deformation accumulating ratio decreased with an increase in cycling period and specimen thickness. 4) Wood suffered 1.5 times as many dimensional changes per unit temperature variation as per unit humidity variation, and this deformation behaved even more seriously under static condition.