Enhancing Astaxanthin Accumulation in Haematococcus pluvialis by Coupled Light Intensity and Nitrogen Starvation in Column Photobioreactors

( Wen-wen Zhang ),( Xue-fei Zhou ),( Ya-lei Zhang ),( Peng-fei Cheng ),( Rui Ma ),( Wen-long Cheng ),( Hua-qiang Chu ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at 200 μmo/m2/s under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

Research on an Improved Ant Colony Optimization Algorithm for Solving Traveling Salesmen Problem

Wenli Lei,Fubao Wang 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.9

In order to improve the search result and low evolution speed, and avoid the tendency towards stagnation and falling into the local optimum of ant colony optimization(ACO) in solving the complex function, the traditional ant colony optimization algorithm is analyzed in detail, an improved ant colony optimization(IWSMACO) algorithm based on information weight factor and supervisory mechanism is proposed in this paper. In the proposed IWSMACO algorithm, the information weight factor is added to the path selection and pheromone adjustment mechanisms in order to dynamically adjust path selection probability and randomly select the behavior rules for further intelligentializing the ant colony. The supervisory mechanism added the dynamic convergence criterion of supervisory distance and used the optimal pheromone update strategy to self-adaptively select the excellent ants for updating the pheromone trails, and improve the solution qualities of each iteration, better guide the later ants for learning. Finally, the proposed IWSMACO algorithm is carried out by 12 TSP instances. The simulation experiment results show that the proposed IWSMACO algorithm can not only avoid falling into the local optimum, but also enhance the convergence speed. And it takes on remarkable optimized ability and higher search accuracy.

Regional allocation of carbon emissions in China based on zero sum gains data envelopment analysis model

Lei Wen,Er Nv Zhang 대한환경공학회 2016 Environmental Engineering Research Vol.21 No.1

Along with China`s increasing share in global total CO₂ emissions, there is a necessity for China to shoulder large emission-mitigating responsibility. The appropriate allocation of CO₂ emission quotas can build up a solid foundation for future emissions trading. In views of originality, an optimized approach to determine CO₂ emissions allocation efficiency based on the zero sum gains data envelopment analysis (ZSG-DEA) method is proposed. This paper uses a non-radial ZSG-DEA model to allocate CO₂ emissions between different Chinese provinces by 2020 and treats CO₂ as the undesirable output variable. Through the calculation of efficiency allocation amounts of provincial CO₂ emissions, all provinces are on the ZSG-DEA efficiency frontier. The allocation results indicate that the cumulative optimal amounts of CO₂ emissions in 2020 were higher than the actual amounts in 13 provinces, and lower in other 17 provinces, and show that different provinces have to shoulder different mitigation burdens in terms of emission reduction.

Energy-related CO₂ emissions in Hebei province

Lei Wen,Yanjun Liu 대한환경공학회 2016 Environmental Engineering Research Vol.21 No.1

The purpose of this study is to identify the driven factors affecting the changes in energy-related CO₂ emissions in Hebei Province of China from 1995 to 2013. This study confirmed that energy-related CO₂ emissions are correlated with the population, urbanization level, economic development degree, industry structure, foreign trade degree, technology level and energy proportion through an improved STIRPAT model. A reasonable and more reliable outcome of STIRPAT model can be obtained with the introducing of the Ridge Regression, which shows that population is the most important factor for CO₂ emissions in Hebei with the coefficient 2.4528. Rely on these discussions about affect abilities of each driven factors, we conclude several proposals to arrive targets for reductions in Hebei`s energy-related CO₂ emissions. The method improved and relative policy advance improved pointing at empirical results also can be applied by other province to make study about driven factors of the growth of carbon emissions.

System dynamic modeling and scenario simulation on Beijing industrial carbon emissions

Lei Wen,Lu Bai,Ernv Zhang 대한환경공학회 2016 Environmental Engineering Research Vol.21 No.4

Beijing, as a cradle of modern industry and the third largest metropolitan area in China, faces more responsibilities to adjust industrial structure and mitigate carbon emissions. The purpose of this study is aimed at predicting and comparing industrial carbon emissions of Beijing in ten scenarios under different policy focus, and then providing emission-cutting recommendations. In views of various scenarios issues, system dynamics has been applied to predict and simulate. To begin with, the model has been established following the step of causal loop diagram and stock flow diagram. This paper decomposes scenarios factors into energy structure, high energy consumption enterprises and growth rate of industrial output. The prediction and scenario simulation results shows that energy structure, carbon intensity and heavy energy consumption enterprises are key factors, and multiple factors has more significant impact on industrial carbon emissions. Hence, some recommendations about low-carbon mode of Beijing industrial carbon emission have been proposed according to simulation results.

Research on an Improved Wireless Sensor Networks Effective Coverage Method

Wenli Lei,Fubao Wang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.11

An improved wireless sensor networks effective coverage method based on differential evolution algorithm is proposed in this paper, which using quadratic interpolation method to improve the algorithm performance to further optimize the effective coverage of wireless sensor network nodes. Simulation results show that, compared to DE algorithm, the new algorithm can improve local search capabilities, reduce the computational cost of the algorithm, accelerate standards DE convergence, improve the accuracy of solution, and has some reference value for optimization application of wireless sensor network.

An Improved Positioning Algorithm of Wireless Sensor Network Based on Differential Evolution

Wenli Lei,Fubao Wang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.9

Localization as a key problem of wireless sensor network technology, has been the subject of widespread attention. This paper presents an improved positioning algorithm of wireless sensor network based on differential evolution(DE). Firstly, the algorithm improves on each jump distance measurement method in the traditional DV-hop algorithm, thereby reducing distance estimation error between anchor nodes and the unknown nodes, and then through the DE algorithm to obtain better positioning accuracy. Simulation results show that improved positioning algorithm has improved significantly in positioning accuracy compared to the previous DE positioning algorithm and least-squares algorithm, under different error factor and the density of anchor nodes. The algorithm has features of good robustness, global search capability and the ability to inhibit the accumulation of errors, suitable for a variety of applications in wireless sensor networks localization.

Numerical Analysis on Mechanical Property of Concrete Filled Steel Tube Reinforced Concrete (CFSTRC) Columns Subjected to ISO-834 Standard Fire

Lei Xu,Lei Xu,Wen-Da Wang,Jian-Gang Sun 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

The present study established a numerical investigation on the behavior of concrete filled steel tube reinforced concrete (CFSTRC) columns subjected to fire. A finite element analysis (FEA) model was built to simulate the performance of CFSTRC columns under combined loading and fire. The FEA model was verified by the experimental results of CFSTRC columns subjected to fire. The comparison demonstrated an acceptable accuracy for the proposed FEA model. Afterwards, the FEA model was used to analyze the failure modes, the redistribution of internal force, the changes and development of the stress and strain, and the contact stress between the tube and concrete of CFSTRC columns subjected to fire. Influencing factors that may affect the bearing capacity of the CFSTRC columns subjected to fire were analyzed. The bearing capacity and stiffness of the CFSTRC columns gradually decreased in the fire; the parameters such as the fire duration time, sectional dimension, slenderness ratio, and sectional core area ratio significantly influenced the bearing capacity of the CFSTRC columns. Finally, a simplified calculating formula was proposed to calculate the influence factors of the bearing capacity of the CFSTRC columns subjected to ISO-834 standard fire. The formula-calculated results were well in agreement with the finite element analysis results, which provide a simple and feasible method for evaluating the fire-resistance design of these types of components in practical engineering.

3D numerical simulation study of Brazilian splitting in calcite vein-bearing shale based on CT scans

Wenli Lei,Zhonghu Wu,Huailei Song,Hengtao Cui,Wentao Wang,Motian Tang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.6

Shale affects reservoir fracture sprouting and expansion during fracture modification. The aim of this study was to investigate the influence of calcite veins with distinct flaw inclinations on the stretch strength and destruction pattern of shale. In the text, we reconstructed 3D numericalmodels of shale with seven groups of different calcite vein inclinations using CT scanning of shale specimens from the Niutitang Formation in the Feng’gang No. 3 block in the northern part of Guizhou Province and performed Brazilian splitting simulation tests. Research shows the effect of the calcite vein angle on the ultimate tensile strength and damage mode of shale, and the damage modes mainly include tensile damage, tensile-shear damage, pressure-shear damage and compression damage. Calcite veins have a significant structural effect on the tensile strength of shale. Due to the change in calcite vein inclination, the stress decomposition on the specimen acts on the positive and shear stresses along the calcite vein direction changes significantly, which results in a large difference in the splitting stress between calcite veins and shale matrix when destabilization damage occurs. The research efforts have a key impact on the crack mechanism of shale hydraulic fracturing, fracture expansion law and the improvement of shale gas recovery rate.

Insufficient radiofrequency ablation-induced autophagy contributes to the rapid progression of residual hepatocellular carcinoma through the HIF-1α/BNIP3 signaling pathway

( Wen-lei Xu ),( Shao-hong Wang ),( Wen-bing Sun ),( Jun Gao ),( Xue-mei Ding ),( Jian Kong ),( Li Xu ),( Shan Ke ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.4

Currently speaking, it is noted that radiofrequency ablation (RFA) has been the most widely used treatment for hepatocellular carcinoma (HCC) occurring in patients. However, accumulating evidence has demonstrated that the incidence of insufficient RFA (IRFA) may result in the identified rapid progression of residual HCC in the patient, which can greatly hinder the effectiveness and patient reported benefits of utilizing this technique. Although many efforts have been proposed, the underlying mechanisms triggering the rapid progression of residual HCC after IRFA have not yet been fully clarified through current research literature reviews. It was shown in this study that cell proliferation, migration and invasion of residual HepG2 and SMMC7721 cells were significantly increased after the IRFA was simulated in vitro. In other words, it is noted that IRFA could do this by enhancing the image of autophagy of the residual HCC cell via the HIF-1 α/BNIP3 pathway. Consequently, the down-regulation of BNIP3 may result in the inhibition of the residual HCC cell progression and autophagy after IRFA. Our present study results suggest that IRFA could promote residual HCC cell progression in vitro by enhancing autophagy via the HIF-1 α/BNIP3 pathway. For this reason, it is noted that the targeting of the BNIP3 may be useful in preventing the rapid growth and metastasis of residual HCC after IRFA. [BMB Reports 2019; 52(4): 277-282]