Efficient Elicitation of Ginsenoside Biosynthesis in Cell Cultures of Panax notoginseng by Using Self-chemically-synthesized Jasmonates

Jian-Jiang Zhong,Wei Wang,Zhen-Jiang Zhao,Yufang Xu,Xuhong Qian 한국생물공학회 2005 Biotechnology and Bioprocess Engineering Vol.10 No.2

A series of fluorine and hydroxyl containing jasmonate derivatives, which were chemically synthesized in our institute, were investigated for their effects on the biosynthesis and heterogeneity of ginsenosides in suspension cultures of Panax notoginseng cells. Compared to the control (without addition of elicitors), 100 M of each of the jasmonate was added on day 4 to the suspension cultures of P. notoginseng cells. It was observed that, jasmonates greatly enhanced the ginsenoside content and the ratio of Rb group to Rg group (i.e. (Rb1 + Rd)/(Rg1 + Re)) in the P. notoginseng cells. Some of the synthetic jasmonates, such as pentafluoropropyl jasmonate (PFPJA), 2-hydroxyethyl jasmonate (HEJA) and 2-hydroxye-thoxyethyl jasmonate (HEEJA), could promote the ginsenoside content to 2.55 0.11, 3.65 0.13 and 2.94 0.06 mg/100 mg DW, respectively, compared to that of 0.64 0.06 mg/100 mg DW for the control and 2.17 0.04 mg/100 mg DW by the commercially available methyl jasmonate (MJA); and they could change the respective Rb:Rg ratio to 1.60 0.04, 1.87 0.01 and 1.56 0.05, compared to that of 0.47 0.01 for the control and 1.42 0.06 by MJA. The results suggest that suitable esterification of MJA with fluorine or hydroxyl group could increase the elicitation activity to induce plant secondary metabolism. The information obtained from this study is useful for hyper-production of heterogeneous products by plant cell cultures.

Experimental and Numerical Analysis on Full High Strength Steel Extended Endplate Connections in Fire

Xuhong Qiang,Nianduo Wu,Xu Jiang,Yongfeng Luo,Frans Bijlaard 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.4

Full-scale experimental study and numerical analysis on behaviors and failure mechanisms of full high strength steel extended endplate connections in fi re have been carried out and presented in this paper. The experimental behaviors of the connections were compared with the provisions of Eurocode 3. The test results show that the failure modes of the connections in fi re are bolt failure with yielding of the fl ange, as same as those at ambient temperature. The failures of the bolts in fi re are ductile while they are brittle at ambient temperature. The rotation capacity of the connections in fi re is proved suffi cient. What is more, at elevated temperature 550 °C, the plastic moment resistances of Q690 and Q960 full high strength steel endplate connections are only 40% of those at ambient temperature, while their initial rotation stiff ness are 66 and 63% respectively. But the rotation capacities of Q690 and Q960 high strength steel endplate connections are 1.38 and 1.74 times of those at ambient temperature. Moreover, it is found that the component method Eurocode 3 proposed based on connections made of mild steels can be used to calculate plastic resistances and to predict failure modes of high strength steel endplate connections in fi re, but it is not suitable to predict their stiff ness. The suggestions about rotation capacity of connections in Eurocode 3 are found too conservative for high strength steel endplate connections in fi re.

Experimental and Theoretical Study on High Strength Steel Extended Endplate Connections After Fire

Xuhong Qiang,Nianduo Wu,Yongfeng Luo,Xu Jiang,Frans Bijlaard 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.2

In order to reveal more information and better understanding on the behavior and failure mechanisms of high strength steel (HSS) extended endplate connections at ambient temperature and after fi re, an experimental and theoretical study has been conducted and presented in this paper. The provisions of Eurocode 3 are verifi ed with the test results. Because strength of bolts decreases more rapidly than that of structural steels, failure modes of endplate connections may change after fi re. Hence, a series of equations are proposed to predict failure modes of endplate connections after fi re. Furthermore, FE simulations which can predicate the performance of HSS extended endplate connections with reasonable accuracy are adopted to study the behaviors of the connections after cooling down from various fi re temperatures and to validate the accuracy of the proposed equations. Moreover, a parametric study is carried out to explore an optimization design method. It is found that the current provisions of EC3 can justifi ably predict failure modes and plastic fl exural resistances of HSS extended endplate connections both at ambient temperature and cooling down from 550 °C, but it is not the case for their initial rotational stiff - ness and rotation capacity. In order to avoid brittle failure mode of endplate connections after fi re, appropriately increasing the diameter or grade of bolts in the design is suggested. What is more, the match of steel grade and thickness of column fl ange and endplate as well as beam should be considered in the optimization design of beam-column endplate connections.

XFEM-based Fatigue Crack Propagation Analysis on Key Welded Connections of Orthotropic Steel Bridge Deck

Xu Jiang,Kai Sun,Xuhong Qiang,Dan Li,Qiwei Zhang 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.2

Orthotropic steel decks(OSD’s) are prone to fatigue cracking under cyclic loads, especially for rib-to-deck welded connection and rib-to-crossbeam welded connection. To reveal fracturing behaviors of these fatigue-prone sites, a multi-scale model of OSD’s specimen is established, including segmental shell-element part and local solid-element configuration. Based on the extended finite element method(XFEM), propagation analysis was carried out in this research. The analysis of stress intensity factor (SIF) shows that the crack at the weld root or weld toe of the rib-to-deck welded connection is a mixed-crack with modes I, II and III, where mode I plays a leading role. Besides, the maximum SIF KI of the crack at the weld toe is slightly larger than that at the weld root. For rib-to-crossbeam welded connection, the maximum SIF KI at the weld toe of the U-rib is greater than that at the weld toe of the crossbeam. The analysis of crack propagation shows that the crack growth rate at the weld toe is faster than that at the weld root with the same initial crack size and loading conditions. Similarly, for rib-to-crossbeam welded connection, the crack propagation at the weld toe of U-rib performs faster than that at the weld toe of crossbeam.

Effects of a chitosan nanoparticles encapsulation on the properties of litchi polyphenols

Xingan Cheng,Qiwen Zou,Hanhui Zhang,Jianwei Zhu,Murtaza Hasan,Fangyun Dong,Xin Liu,Junjie Li,Yuehua Wu,Xiaojing Lv,Keqiang Wang,Xiangling Deng,Zhanmei Liu,Xuhong Jiang 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.13

Litchi polyphenols have very specific biological activities. Nevertheless, the low and inconsistent oral bioavailability and instability hinder the further application of litchi polyphenols in food systems. This work prepared litchi polyphenols loaded chitosan nanoparticles (LP-CSNPs) by ionic gelation method to enhance the encapsulation on the properties of litchi polyphenols. The optimum conditions of formation via single factors and the Box–Behnken design were chitosan (CS) concentration 1.065 mg/mL, sodium tripolyphosphate (TPP) concentration 0.975 mg/mL, and the mass ratios of polyphenols and CS 1:1 with encapsulation efficiency (EE%) of 45.53%. LP-CSNPs presented the nanosized range of particle size (mean 170 nm), excellent polydispersity index (PDI) (0.156 ± 0.025), and zeta potential values (+ 35.44 ± 0.59). The in vitro release in simulated gastric fluid (pH 1.2) and intestinal fluid (pH 6.8) during 100 h was 58.34% and 81.68%, respectively. LP-CSNPs could effectively improve the storage stability and had great antibacterial activity compared with unencapsulated litchi polyphenols.