Optimal Selection of Agricultural Products to Inhibit Citrinin Production during Submerged Culture of Monascus anka

Xu Xiong,Xuehong Zhang,Zhenqiang Wu,Zhilong Wang 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.6

Agricultural products exhibit a “buffering nature”during autoclaving and fermentation processes: i.e., thefinal pH of agricultural product medium after Monascusfermentation maintains a certain value. The protein contentof agricultural products strongly affects the bufferingcapacity and an extremely low final pH, below 3, can beachieved by the selection of agricultural products with lowprotein content, such as rice meal and cornmeal. This lowpH can be used to inhibit citrinin biosynthesis duringMonascus fermentation. Thus, optimal selection of agriculturalproducts with low protein content may provide a novelstrategy to inhibit citrinin production in submerged cultureof Monascus anka at a low initial pH for the production ofMonascus pigments. pH values ranging from 2.6 to 3 canbe maintained in Monascus fermentation using cornmeal/wheat starch (30:30 g/L) as substrate at initial pH 2.5,where the concentration of intracellular pigments reaches45 AU at 470 nm while citrinin is undetectable by TLCanalysis.

Design of a variable valve hydraulic lift system for diesel engine

Zhilong Hu,Yong Gui,Min Xu,Kangyao Deng,Yi Cui,Jiayong Dou 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

A continuous variable valve lift (VVL) mechanism for a diesel engine is proposed in this research. The hydraulic mechanism, whichconsists of a driving plunger, a driven plunger, a hydraulic cylinder, and a hydraulic oil tank, is the key part of the VVL mechanism. Simulation is conducted to study the relationship between maximum valve lift and rotation angle of driving plunger. Calculation resultsindicate that the maximum valve lift decreases with increasing rotation angle. A prototype was manufactured and successfully tested in asingle-cylinder diesel engine. The experiments, which were conducted at different rotation angles of the driving plunger, validate theaccuracy of the calculation results. The difference between experimental valve lift curve and cam lift curve is considered the result of oilleakage. Rotating the driving plunger is an effective method to regulate valve lift. Working stability of the VVL mechanism is validatedthrough a multi-cycle operation. Experimental results indicate that the VVL mechanism is effective and reliable for realizing continuousVVL in engines.

Online Safe Flight Envelope Protection for Icing Aircraft Based on Reachability Analysis

Zhilong Yu,Yinghui Li,Zhe Zhang,Wenfeng Xu,Zehong Dong 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.4

Icing encountered by an aircraft in flight can pose a great threat to flight safety, which is the foremost concern in aviation. Ice accretion has nonlinear and coupling properties, and therefore, a conventional envelope protection system cannot successfully deal with the condition. A safe flight envelope based on reachability analysis is proposed in this paper as a basis for designing an online envelope protection system for aircraft under icing conditions. This system uses a neural network method to identify changes in the aerodynamic coefficients and to classify the degrees of icing and uses a database-driven approach to solve the onboard safe flight envelope computation problem. The database of icing safe flight envelopes is created offline and can be retrieved in real time. The Research Civil Aircraft Model (RCAM) encountering icing conditions in the climbing phase was taken as an example to verify the feasibility of the online safe flight envelope protection system. The simulation results showed that the system can classify the degrees of icing efficiently, prevent the aircraft from deviating from the safe flight envelope, guide it back to the envelope along the fastest path, and reduce the risk of loss of control under icing conditions.

Facile and scalable synthesis of nitrogen-doped ordered mesoporous carbon for high performance supercapacitors

Lei Fan,Peizheng Sun,Li Yang,Zhilong Xu,Jie Han 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1

Nitrogen-doped carbon has been receiving tremendous research interest due to its exotic electrochemical performance and catalyzing capability. Nevertheless, large-scale synthesis of ordered, mesoporous, nitrogen-doped carbon for supercapacitors is rarely reported due to the complexity and uncontrollable property of polymerization of carbon/ nitrogen precursors. In this work, we report a facile and efficient approach for mass production of nitrogen-doped carbon, with a narrow pore size distribution and a sheet morphology, via a simple solution casting of biomass-based mixture. Upon drying, the gelatin molecules self-assemble into sheets, and guide the homogeneous loading of sacrificial silica nanospheres. Further carbonization and template removal procedures allow the low-cost production of nitrogendoped carbon sheets in the absence of complex polymerization. As a result, nitrogen-doped carbon sheets possess a high nitrogen content and ordered, interconnected mesoporous channels, with porosity parameters being carbonization temperature and template size dependence. Additionally, nitrogen-doped, ordered carbon sheets exhibit high performance for supercapacitor application, including high specific capacitances and energy/power densities. This work demonstrates a unique route to synthesizing ordered mesoporous nitrogen-doped carbon sheets via a scalable, low-cost method, which may shed light on many other applications aside from energy storage, such as water splitting, catalysis and sensor.

Optimization design and dynamic stability analysis of 3-DOF cable-driven parallel robot with an elastic telescopic rod

Wei Zhu,Jiahong Liu,Kuanxiang Shi,Fei Qi,Huiping Shen,Zhu Xu,Zhilong Ma 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

This paper proposes a three degree-of-freedoms (DOFs) cable-driven parallel robot (CDPR), which is actuated by three groups of parallel cables and tensioned by an elastic telescopic rod with a passive spring. Firstly, the architecture of the robot is briefly illustrated with emphasis on the three parallelogram arrangements of the cables and composition of elastic telescopic rod structure. This robot has larger workspace and greater tension than previous under-constrained CDPRs. Secondly, the kinematic and dynamic models of the robot are established. On this basis, the parameters of the spring installed in the telescopic rod are optimized and determined considering both the acceleration and cable force through using the differential evolution (DE) algorithm. Thirdly, dynamic stability analysis of the robot under impulsive disturbances is performed according to the Gauss principle of least constraint (GPLC). The results of a simulation case show that this robot has better dynamic stability in comparison with conventional under-constraint CDPR because of the presence of the elastic telescopic rod. The measurement results in the workspace are obtained through dynamic simulation. Finally, the experiments are performed based on numerical simulation. The feasibility of the CDPR is verified via the experiments and simulations.

Melatonin Attenuates Mitochondrial Damage in Aristolochic Acid-Induced Acute Kidney Injury

Sun Jian,Pan Jinjin,Liu Qinlong,Cheng Jizhong,Tang Qing,Ji Yuke,Cheng Ke,wang Rui,Liu Liang,Wang Dingyou,Wu Na,Zheng Xu,Li Junxia,Zhang Xueyan,Zhu Zhilong,Ding Yanchun,Zheng Feng,Li Jia,Zhang Ying,Yua 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.1

Aristolochic acid (AA), extracted from Aristolochiaceae plants, plays an essential role in traditional herbal medicines and is used for different diseases. However, AA has been found to be nephrotoxic and is known to cause aristolochic acid nephropathy (AAN). AA-induced acute kidney injury (AKI) is a syndrome in AAN with a high morbidity that manifests mitochondrial damage as a key part of its pathological progression. Melatonin primarily serves as a mitochondria-targeted antioxidant. However, its mitochondrial protective role in AA-induced AKI is barely reported. In this study, mice were administrated 2.5 mg/kg AA to induce AKI. Melatonin reduced the increase in Upro and Scr and attenuated the necrosis and atrophy of renal proximal tubules in mice exposed to AA. Melatonin suppressed ROS generation, MDA levels and iNOS expression and increased SOD activities in vivo and in vitro. Intriguingly, the in vivo study revealed that melatonin decreased mitochondrial fragmentation in renal proximal tubular cells and increased ATP levels in kidney tissues in response to AA. In vitro, melatonin restored the mitochondrial membrane potential (MMP) in NRK-52E and HK-2 cells and led to an elevation in ATP levels. Confocal immunofluorescence data showed that puncta containing Mito-tracker and GFP-LC3A/B were reduced, thereby impeding the mitophagy of tubular epithelial cells. Furthermore, melatonin decreased LC3A/B-II expression and increased p62 expression. The apoptosis of tubular epithelial cells induced by AA was decreased. Therefore, our findings revealed that melatonin could prevent AA-induced AKI by attenuating mitochondrial damage, which may provide a potential therapeutic method for renal AA toxicity.