Bioconversion of Pinoresinol Diglucoside from Glucose Using Resting and Freeze-Dried Phomopsis sp. XP-8 Cells

( Zhenhong Gao ),( Muhammad Shahid Riaz Rajoka ),( Jing Zhu ),( Zhiwei Zhang ),( Yan Zhang ),( Jinxin Che ),( Xiaoguang Xu ),( Junling Shi ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Phomopsis sp. XP-8 (an endophytic fungus) was previously found to produce pinoresinol diglucoside (PDG), a major antihypertensive compound of Tu-Chung (the bark of Eucommia ulmoides Oliv.), which is widely used in Chinese traditional medicines. In the present study, two bioconversion systems were developed for the production of PDG in Tris-HCl buffer containing glucose and Phomopsis sp. XP-8 cells (both resting and freeze-dried). When other factors remained unchanged, the bioconversion time, glucose concentration, cell ages, cell dosage, pH, temperature, and stirring speed influenced PDG production in a similar and decreasing manner after an initial increase with increasing levels for each factor. Considering the simultaneous change of various factors, the optimal conditions for PDG production were established as 70 g/l cells (8-day-old), 14 g/l glucose, 28°C, pH 7.5, and 180 rpm for systems employing resting cells, and 3.87 g/l cells, 14.67 g/l glucose, 28°C, pH 7.5, and 180 rpm for systems employing freeze-dried cells. The systems employing freeze-dried cells showed lower peak PDG production (110.28 μg/l), but at a much shorter time (12.65 h) compared with resting cells (23.62 mg/l, 91.5 h). The specific PDG production levels were 1.92 and 24 μg per gram cells per gram glucose for freeze-dried cells and resting cells, respectively. Both systems indicated a new and potentially efficient way to produce PDG independent of microbial cell growth.

A numerical study on ice failure process and ice-ship interactions by Smoothed Particle Hydrodynamics

Zhang, Ningbo,Zheng, Xing,Ma, Qingwei,Hu, Zhenhong The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

In this paper, a Smoothed Particle Hydrodynamics (SPH) method is extended to simulate the ice failure process and ice-ship interactions. The softening elastoplastic model integrating Drucker-Prager yield criterion is embedded into the SPH method to simulate the failure progress of ice. To verify the accuracy of the proposed SPH method, two benchmarks are presented, which include the elastic vibration of a cantilever beam and three-point bending failure of the ice beam. The good agreement between the obtained numerical results and experimental data indicates that the presented SPH method can give the reliable and accurate results for simulating the ice failure progress. On this basis, the extended SPH method is employed to simulate level ice interacting with sloping structure and three-dimensional ice-ship interaction in level ice, and the numerical data is validated through comparing with experimental results of a 1:20 scaled Araon icebreaker model. It is shown the proposed SPH model can satisfactorily predict the ice breaking process and ice breaking resistance on ships in ice-ship interaction.

Antifreeze protein detection using Rhodamine B as photoluminescence label in porous silicon

Hongyan Zhang,Zhenhong Jia,Xiaoyi Lv,Junwei Hou,Xiaojing Liu,Ji Ma,Jun Zhou 한국물리학회 2013 Current Applied Physics Vol.13 No.4

A novel method is demonstrated to detect Antifreeze proteins (AFPs) based on photoluminescence (PL)using porous silicon (PS) coated with silver as a substrate. Ag/PS substrate is obtained through immersion of PS in silver nitrate (AgNO3) solutions and is incubated with Rhodamine B (RB) as PL label. This substrate is easy to be fabricated and the pore size of PS is large enough for biological molecules to infiltrate, which is an ideal platform for biological molecule detection. Through functionalization used glutaraldehyde (GTA) and 4-(N-Maleimidomethyl) cyclohexane-1-carboxylicacid (Sulfo-SMCC) as crosslinkers separately, we test the role of the AFPs antibodies in selective capturing the AFPs antigen and explain the reason of the enhancement of PL intensity. The result shows a significant enhancement of the PL intensity of RB at around 590 nm due to the interaction of antibodyeantigen competitive binding with AFPs. Therefore, the PL corresponding to RB was selected to detect the target AFPs and the PL intensity of RB proportional to the AFPs concentration. The detection limit was found to be 1.65 mg/ml for AFPs when GTA was used as cross-linker, and the detection limit was 16.5 ng/ml with Sulfo-SMCC as cross-linker

A numerical study on ice failure process and ice-ship interactions by Smoothed Particle Hydrodynamics

Ningbo Zhang,Xing Zheng,Qingwei Ma,Zhenhong Hu 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

In this paper, a Smoothed Particle Hydrodynamics (SPH) method is extended to simulate the ice failure process and ice-ship interactions. The softening elastoplastic model integrating Drucker-Prager yield criterion is embedded into the SPH method to simulate the failure progress of ice. To verify the accuracy of the proposed SPH method, two benchmarks are presented, which include the elastic vibration of a cantilever beam and three-point bending failure of the ice beam. The good agreement between the obtained numerical results and experimental data indicates that the presented SPH method can give the reliable and accurate results for simulating the ice failure progress. On this basis, the extended SPH method is employed to simulate level ice interacting with sloping structure and three-dimensional iceship interaction in level ice, and the numerical data is validated through comparing with experimental results of a 1:20 scaled Araon icebreaker model. It is shown the proposed SPH model can satisfactorily predict the ice breaking process and ice breaking resistance on ships in ice-ship interaction.

Surface layer reflective index changes of Au nanoparticle functionalized porous silicon microcavity for DNA detection

Hongyan Zhang,Zhenhong Jia,Xiaoyi Lv 한국물리학회 2015 Current Applied Physics Vol.15 No.8

A technique is demonstrated to detect DNA hybridization based on surface layer of Au/porous silicon microcavity (Au/PSM) substrate for very small amount of biomolecules. Simulations show that the increase of effective refractive index for the first layer of PSM will cause a blue shift for its reflectance spectrum, and the blue shift becomes less with the increase of refractive index for one more layers. In experiments, such a blue shift of reflectance spectrum of PSM comes from the increase of refractive index by DNA hybridization on the surface. The detection limit of Au/PSM biosensor is 15.15 nM for 19-base pair DNA, which is comparable to that of reported biosensors based on porous silicon (PS). Therefore such an Au/PSM could be very useful to develop simple, rapid and sensitive optical biosensors when the amount of target is very small.

Simulation and experiment study of burrs in micro-milling Zr-based metallic glass

Jiachun Wang,Zhenhong Zhang,Chuang Zhang,Jiabin Fu,Jianchao Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

Metallic glass has been widely used in making micro parts and equipment due to its excellent physical and chemical performance. A large quantity of burrs is produced in the micro-milling process that is hard to remove and seriously affects the quality and precision of the parts. Burrs should be effectively restrained; however, the burrs’ type, position and the effect of milling parameters on burrs’ generation in micro-milling metallic glass have not been systematically studied. In this paper, by using 3-D FEM simulation and taking micro-milling experiments of Zr-based metallic glass (Vit1), the burrs in flat-end milling and ball-end milling micro grooves were investigated. The burrs’ type and position were observed and summarized, the formation process of various burrs was analyzed in detail, and the influence of cutting parameters on burrs was clarified. Comparing the simulation and experiment result, we could confirm that the top burr and the entrance burr were produced during the processing of the flatend milling cutter, and ball-end milling cutter effectively inhibits the production of the top burr but takes no actions on burrs’ generation at the entrance and the bottom of the groove. The main cause of the top burr is the extrusion of the tool, and the extrusion of the cutting layer metal and chip accumulation were the main reason for entrance and exit burrs. Reducing the axial cutting depth could effectively restrain the generation of burrs for both two kinds of milling tools.

Incremental extended finite element method for thermal cracking of mass concrete at early ages

Zhenyang Zhu,Guoxin Zhang,Yi Liu,Zhenhong Wang 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.1

Thermal cracks are cracks that commonly form at early ages in mass concrete. During the concrete pouring process, the elastic modulus changes continuously. This requires the time domain to be divided into several steps in order to solve for the temperature, stress, and displacement of the concrete. Numerical simulations of thermal crack propagation in concrete are more difficult at early ages. To solve this problem, this study divides crack propagation in concrete at early ages into two cases: the case in which cracks do not propagate but the elastic modulus of the concrete changes and the case in which cracks propagate at a certain time. This paper provides computational models for these two cases by integrating the characteristics of the extended finite element algorithm, compiles the corresponding computational programs, and verifies the accuracy of the proposed model using numerical comparisons. The model presented in this paper has the advantages of high computational accuracy and stable results in resolving thermal cracking and its propagation in concrete at early ages.

A New Approach to Produce Resveratrol by Enzymatic Bioconversion

( Jinxin Che ),( Junling Shi ),( Zhenhong Gao ),( Yan Zhang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.8

An enzymatic reaction system was developed and optimized for bioconversion of resveratrol from glucose. Liquid enzyme extracts were prepared from Alternaria sp. MG1, an endophytic fungus from grape, and used directly or after immobilization with sodium alginate. When the enzyme solution was used, efficient production of resveratrol was found within 120 min in a manner that was pH-, reaction time-, enzyme amount-, substrate type-, and substrate concentration-dependent. After the optimization experiments using the response surface methodology, the highest value of resveratrol production (224.40 ug/l) was found under the conditions of pH 6.84, 0.35 g/l glucose, 0.02 mg/l coenzyme A, and 0.02 mg/l ATP. Immobilized enzyme extracts could keep high production of resveratrol during recycling use for two to five times. The developed system indicated a potential approach to resveratrol biosynthesis independent of plants and fungal cell growth, and provided a possible way to produce resveratrol within 2 h, the shortest period needed for biosynthesis of resveratrol so far.

Optical properties of InN rods on sapphire grown by metal–organic chemical vapor deposition

Sun, Yuanping,Cho, Yong-Hoon,Dai, Zhenhong,Wang, Weitian,Wang, Hui,Wang, Lili,Zhang, Shuming,Yang, Hui Elsevier 2010 Physica E, Low-dimensional systems & nanostructure Vol.43 No.1

<P><B>Abstract</B></P><P>The InN rods were grown by metal–organic chemical vapor deposition with a density of 1.4×10<SUP>9</SUP>cm<SUP>−2</SUP>. Optical properties of InN rods have been systematically investigated by means of temperature dependent photoluminescence (PL) and power dependent PL. Four peaks appear in the PL spectra and the origination was analyzed. The lowest energy peak P1 (0.665eV) is attributed to transitions of conduction band electrons to the photo-holes captured by deep acceptor; P2 (0.717eV) is the direct band-to-band transition peak of InN; main peak P3 (0.759eV) results from the recombination of degenerate electrons with photo-holes near the top of the valence band (Burstein–Moss effects); the high energy shoulder P4 (0.787eV) was by the co-effect of quantum confinement and the Burstein–Moss effects due to the small size distribution of InN wetting layers.</P>