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Qinting He,Hanjie Ying,Nan Li,Xiaochun Chen,Qi Ye,Jianxin Bai,Jian Xiong 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2
Nuclease p1 is an important enzyme in the nucleotide industry that is used to hydrolyze nucleic acid into nucleotides. To improve enzyme activity, Penicillium citrinum, a nuclease p1 producing strain, was mutated by lowenergy Nitrogen ion beam implantation at an energy level of 15 keV and a dose ranging from 1×10^(15)-1×10^(16) ions/cm^2. The mutant strain designated as N409 was obtained with a high yield of nuclease p1. The activity of nuclease p1 was 421 U/mL from the mutant strain N409, which was increased by 86% compared with the control. The fermentation kinetics of nuclease p1 by the mutant strain N409 was studied in a 30 L external airlifting bioreactor. A model was proposed using the logistic equation for microbial growth, the Luedeking-Piret equation for product formation and a Luedeking-Piret-like equation for substrate uptake. The results predicted from the model were in good agreement with the experimental observations.
Yuman Zhou,Hongbo Wang,Jianxin He,Kun Qi,Bin Ding,Shizhong Cui 한국섬유공학회 2018 Fibers and polymers Vol.19 No.10
Electrospinning is a simple and cost-effective method to prepare fiber with nanometer scale. More importantly, 3D flexible nanofiber yarns that fabricated by electrospinning have shown excellent application prospects in smart textiles, wearable sensors, energy storage devices, tissue engineering, and so on. However, current methods for preparing electrospinning nanofiber yarns had some limitations, including low yarn yield and poor yarn structure. In this paper, a stepped airflow-assisted electrospinning method was designed to prepare continuously twisted nanofiber yarn through introducing stepped airflow into traditional electrospinning system. The stepped airflow could not only help to improve nanofiber yield, but also good for controlling the formed nanofibers to be deposited in a small area. In addition, the experimental methods of single factor variables were used to study the effects of stepped airflow pressure, applied voltage, spinning distance, solution flow rate, air pumping volume and friction roller speed on nanofiber yarn yield, nanofiber diameter, yarn twist and mechanical property. The results showed that prepared nanofiber yarns exhibited perfect morphologies and the yield of nanofiber yarn could reach to a maximum of 4.207 g/h. The breaking strength and elongation at break of the prepared yarn could reach to 23.52 MPa and 30.61 %, respectively.
Hanjie Ying,Jingjing Xie,Nan Li,Ying He,Yong Chen,Xiaochun Chen,Jianxin Bai,Jinglan Wu 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.4
Adenylate cyclase (EC 4.6.1.1) catalyzes the formation of cyclic adenosine-3',5'-monophosphate (cAMP)from adenosine 5'-triphosphate (ATP). Recombinant Escherichia coli overexpressing adenylate cyclase was used to synthesize cAMP by whole cell catalysis. Some key parameters were examined during the catalytic process, while pH and Mg2+ were found to influence cAMP production significantly. Optimum conditions were pH 8.52 and 30 oC with 77.2 mM Mg2+ in 100 mM Tris-HCl buffer, including 0.25% Triton-X 100 as detergent and 30 mM pyruvate sodium as enzyme activator for 6 h. 14.93 g/L of cAMP was produced with a conversion rate of 91.5%. The current work provided a potential way for the industrial production of cAMP.
A Novel and Low-Cost Method for Measuring Wind Speed and Flow in Pipeline
Xuetang Lei,Huoxi Xu,Yang Zhao,Jianxin He 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.8
This paper proposes a new method for measuring the wind speed in the pipe, which overcomes the shortcomings of the traditional mechanical instrument with lower accuracy and ultrasonic measurement method with the high cost, it has the advantages of low cost and high precision. This paper introduces the principle of pendulum method to measure wind speed, the wind speed in the pipe is calculated by the space angle based on the spatial geometric relationship. On the other hand, the space angle is obtained by horizontal angle and vertical angle, which are gathered by the cameras placed in the ends of the bracket. Image processing technology is an important part of this method, including the image gray processing, binarization processing, edge detection and Hough transform steps, at last, the experimental results proved the feasibility of this method.
Hanjie Ying,Ting Fang,Xiaochun Chen,Nan Li,He Song,Jianxin Bai,Jian Xiong 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.6
Statistical experimental designs were used to optimize the composition of culture media for the production of D-ribose by Bacillus subtilis. A fractional factorial design 2(5-2) was used to determine medium components that significantly affected D-ribose production. The concentrations of glucose and (NH4)2SO4 were the significant factors. Central composite design and response surface methodology were then used to estimate the quadratic response surface and determine the factor levels for maximum production of D-ribose. Finally, the optimal medium composition was obtained (g/L): glucose, 172.75; (NH4) 2SO4, 13.2; yeast powder, 4; corn steep liquor, 8 and MnSO4, 0.5. This optimization strategy increased D-ribose production from 73.21 g/L to 88.57 g/L, an increase of 22% compared with the original conditions. The D-ribose production yield to glucose concentration was also enhanced from 0.37 g/g to 0.52 g/g. Confirmatory experiments were also performed to demonstrate the accuracy of the model. Under the optimal medium using ammonia to control pH in a 5 L fermenter, the D-ribose yield was increased to 95.28 g/L after 3 days of cultivation at 37 oC.
Regulating surface-pore structure of PES UF membrane by addition of ‘‘active” nano-CaCO3
Mantong Gao,Shenghuan Wang,Yanhong Ji,Zhengyu Cui,Feng Yan,Mohammad Younas,Jianxin Li,Benqiao He 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-
A small surface-pore ultrafiltration membrane with a high surface porosity was fabricated from a polyethersulfone (PES) dope solution containing a small quantity of CaCO3 nanoparticles (nano-CaCO3),which coagulated in dilute HCl solution. During membrane formation, CO2 nanobubbles were in-situ generatedto delay phase inversion, which ameliorated the membrane structure and performance becauseCO2 nanobubbles are amphiphobic to water and solvent. With increasing nano-CaCO3 content (from 0to 0.15%) in the dope solution, the surface porosity and the surface-pore density of the obtained PESUF membrane were markedly increased from 1.76 to 6.50% and from 8.31 1014 to 5.08 1015 m2,respectively. Nonetheless, the surface-pore size decreased from 13.35 to 8.29 nm, and so as the distribution. The optimal membrane exhibited a high pure water flux (698.2 Lm2h1) and a high rejection tobovine serum album (>99%) with a moderate anti-fouling ability. This work would be of great significancefor precision separation in biopharmaceutical, food processing, and other related applications.
Ye, Junxiao,Pei, Xing,Cui, Hui,Yu, Zhili,Lee, Hyukjin,Wang, Jianxin,Wang, Xu,Sun, Lu,He, Huining,Yang, Victor C. THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.63 No.-
<P><B>Abstract</B></P> <P>The covalent attachment of CPPs to siRNA molecules offers great potential for CPP-mediated siRNA delivery. We recently reported a concise and high-yield synthesis strategy of the cell-permeable, cytosol-dissociable LMWP-siRNA covalent conjugate. Herein, cell uptake mechanism and cellular toxicity studies of this conjugate were performed to evaluate the potential of LMWP-siRNA conjugate for clinical translation. Cellular uptake mechanism study indicated that the conjugate could be taken up by cells via multiple pathways, including direct penetration of the plasma membrane and clathrin- and caveolae-independent endocytosis. <I>In vitro</I> cytotoxicity study revealed that the conjugation promoted internalization in a low-toxic fashion.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
ZIF-8 Modified Nanofiber Composite Window Screen for Efficient Indoor PM2.5 and Formaldehyde Removal
Fan Liu,Tong Lu,Wanjun Bu,Hewei Xiang,Junjie Yang,Junli Li,Xu Zhao,Weili Shao,Qingqing Ni,Jianxin He 한국섬유공학회 2022 Fibers and polymers Vol.23 No.8
Because people spend a lot of time indoors every day, the presence of particulate matter with a diameter less than2.5 μm (PM2.5) and volatile organic molecular substances in indoor air adversely affect public health. These toxic compoundscan be removed from the air using high-efficiency air-filter materials with adsorption capacity. Metal-organic frameworks(MOFs) are among the most suitable materials for air purification as they are synthetic porous materials with excellentadsorption ability. In this study, the zeolitic imidazolate framework-8 (ZIF-8) is uniformly grown on the surface ofpolyacrylonitrile (PAN) nanofibers using an in situ growth method to prepare ZIF-8@PAN nanofiber composite membranes. The nanofiber composite membrane effectively removes PM2.5 and formaldehyde from the air. After loading the optimalamount of ZIF-8, the filtration efficiency of the nanofiber membrane for salt aerosol with a diameter of 0.3 μm increases from90.3 % to 96.9 %, and the removal rate of formaldehyde becomes 98 % within 20 min in the enclosed space of the laboratory. Moreover, after five repeated tests, the formaldehyde adsorption rate remains above 80 %. In addition, ZIF-8@PANnanofiber membranes are used to fabricate anti-haze window screens, which have great potential to improve indoor airquality and mitigate related health risks.
Weili Shao,Wanli Yue,Gaihuan Ren,Chen Cui,Junpeng Xiong,Ling Wang,Tong Lu,Wanjun Bu,Fan Liu,Jianxin He 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5
Electrospun nanofibers are widely used in air-filtration materials because of their fine fiber diameter, small poresize, and high porosity. However, nanofiber membranes exhibit a dense structure, such that they present a large resistance toany air flow. In this study, we set out to design and develop composite nanofiber materials with fluffy structures, as well asblended structures of coarse and fine fibers, through electrospinning technology. These materials could be used in airfiltration applications, given that they offer high efficiency and low resistance. The results show that, compared with purePAN nanofibers, the diameter of PAN nanofibers doped with CNT decreased from 192.36 to 124.37 nm; when the spinningratio of PS coarse fiber (1053 nm) and PAN/CNT fine fiber is 3:1, the resulting nanofiber membrane materials has an obviousthree-dimensional structure, with a specific surface area of 103.16 m2/g, a pore size of 2.25 μm, and a quality factor of0.0947 Pa-1. Under test conditions featuring an air flow of 32 L/min, and 0.3 μm NaCl aerosol particles, the filtrationefficiency was 99.37 % and the resistance was 35 Pa. Furthermore, the dust-holding capacity of the nanofiber air-filter paperwas found to be almost the same as that of melt-blown air-filter papers. Even after being water-soaked 50 times, the filteringefficiency of the nanofiber air-filter paper was still higher. Interestingly, the nanofiber membrane materials doped with CNTalso exhibited excellent sound-absorption abilities. Thus, the composite nanofiber material could potentially be applied toareas with serious air pollution and high noise pollution.