Insecticidal Activity and Histopathological Effects of Vip3Aa Protein from Bacillus thuringiensis on Spodoptera litura

( Feifei Song ),( Yunfeng Lin ),( Chen Chen ),( Ensi Shao ),( Xiong Guan ),( Zhipeng Huang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.10

Vegetative insecticidal proteins (Vips) are insecticidal proteins synthesized by Bacillus thuringiensis during the vegetative stage of growth. In this study, Vip3Aa protein, obtained by in vitro expression of the vip3Aa gene from B. thuringiensis WB5, displayed high insecticidal activity against Spodoptera litura aside from Spodoptera exigua and Helicoverpa armigera. Bioassay results showed that the toxicity of Vip3Aa protein against S. litura larvae statistically decreased along with the increase of the age of the larvae, with LC₅₀ = 2.609 ng/cm² for neonatal larvae, LC₅₀ = 28.778 ng/cm² for first instar larvae, LC₅₀ = 70.460 ng/cm² for second instar larvae, and LC₅₀ = 200.627 ng/cm² for third instar larvae. The accumulative mortality of 100% larvae appeared at 72 h for all instars of S. litura larvae, when feeding respectively with 83.22, 213.04, 341.40, and 613.20 ng/cm² of Vip3Aa toxin to the neonatal and first to third instar larvae. The histopathological effects of Vip3Aa toxin on the midgut epithelial cells of S. litura larvae was also investigated. The TEM observations showed wide damage of the epithelial cell in the midgut of S. litura larvae fed with Vip3Aa toxin.

New measurement method of Poisson's ratio of PVA hydrogels using an optical flow analysis for a digital imaging system

Chen, Feifei,Kang, Dong-Joong,Park, Jun-Hyub IOP Pub 2013 Measurement Science and Technology Vol.24 No.5

<P>In this paper, we propose a method to observe deformation, to measure strain and to calculate Poisson's ratio of a soft material such as a polyvinyl alcohol hydrogel by means of an optical flow analysis during a tensile test. Compared to the conventional digital image correlation method of which the basic assumption is that the local target region in an image is under linear deformation, an optical flow method can measure local deformation up to the pixel level of the image. In addition, sub-pixel measurements are possible by means of bi-cubic interpolation of each flow vector. To guarantee the accuracy of the optical flow vectors, the scale-invariant feature transform was used. Random sample consensus (RANSAC) for eliminating noisy features and then obtaining a more accurate result was applied. The mean value of Poisson's ratio is 0.4498 and the standard deviation comes to 0.0305. This optical flow method can also be applied to calculate Poisson's ratio of other soft materials.</P>

Robust Observer Based Fault-tolerant Control for One-sided Lipschitz Markovian Jump Systems with General Uncertain Transition Rates

Feifei Chen,Dunke Lu,Xiaohang Li 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.7

This paper presents an integrated design of adaptive sliding mode observer and fault-tolerant control for aclass of one-sided Lipschitz Markovian jump systems with general uncertain transition rates. In the design process,an adaptive sliding mode observer is first constructed to estimate the states of the original system without knowingany information of the unknown input. Then a fault-tolerant control strategy is therefore proposed to stabilize theclosed-loop system against the unknown input. Sufficient conditions of the existences of the designed observer andcontroller are deduced in the forms of linear matrix inequalities. In the end, several examples are given to illustratethe effectiveness and make some comparisons with other results.

Family History, Tobacco Smoking, and Risk of Ischemic Stroke

Mengyu Fan,Jun Lv,Canqing Yu,Yu Guo,Zheng Bian,Songchun Yang,Ling Yang,Yiping Chen,Feifei Li,Yaoming Zhai,Ping Wang,Junshi Chen,Zhengming Chen,Lu Qi,Liming Li 대한뇌졸중학회 2019 Journal of stroke Vol.21 No.2

Background and Purpose Both genetic factors and smoking are associated with ischemic stroke (IS) risk. However, little is known about the potential interaction of these factors. We aimed to assess whether smoking and a positive family history interact to increase the risk of IS. Methods The nationwide prospective study recruited 210,000 men and 300,000 women in 2004 to 2008 at ages 30 to 79 years. During 9.7 years of follow-up, we documented 16,923 and 20,656 incident IS cases in men and women without major chronic diseases at baseline, respectively. Multivariable Cox regression models were used to examine associations between family history and IS. Likelihood ratio tests were used to test the smoking-family history interactions on IS. Results About 67.8% (n=135,168) of men ever smoked regularly compared with 2.7% (n=7,775) of women. Among men, a significant interaction between family history and smoking on IS was observed (P for interaction=0.03), with more pronounced association between family history and IS among ever-regular smokers (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.16 to 1.27) than among never-smokers (HR, 1.11; 95% CI, 1.01 to 1.23). The association between family history and IS among ex-smokers after more than 10 years of cessation (HR, 1.01; 95% CI, 0.85 to 1.20) appeared similar to that among never-smokers. Among women, a similar but not significant interaction between family history and smoking on IS was observed. Ever-regular smokers who had a family history of stroke had the highest risk of IS. Conclusions Among Chinese men, the association of family history with IS was accentuated by smoking, and such accentuation tended to be lowered by cessation.

Temperature dependent defence of Nicotiana tabacum against Cucumber mosaic virus and recovery occurs with the formation of dark green islands

Feifei Zhao,Yanan Li,Li-juan Chen,Lisha Zhu,Han Ren,Honghui Lin,Dehui Xi 한국식물학회 2016 Journal of Plant Biology Vol.59 No.3

Temperature is an important environmental factor controlling plant growth, development, and immune response. However, the role of temperature in plant disease resistance is still elusive. In the present study, the potential effects of temperature on the interaction between Nicotiana tabacum and Cucumber mosaic virus (CMV) were investigated. Our results indicated that N. tabacum plants displayed severe symptoms at early stage of post inoculation at high temperature (HT, 28°C), associated with higher viral replication level, more serious stress damages. By contrast, low temperature (LT, 18°C) effectively delayed the replication of CMV compared with elevated temperatures. Additionally, quantitative real-time PCR analyses revealed that lower temperatures (≤ 24°C) promote salicylic acid (SA) dependent responses, whereas higher temperatures (> 24°C) activate the genes expression of jasmonic acid (JA) pathway. Interestingly, the dark green islands (DGIs) appeared much earlier in CMV-inoculated plants grown at HT compared with those at LT and the accumulation of virus small interfering RNAs in plants were significantly up-regulated under elevated temperatures at early stage of post inoculation. Taken together, these results indicated that temperature changes had important effects on plant defence response, and different temperatures could induce different immune pathways of N. tabacum against CMV infection.

Silica Nano-particle Anneal Treatment and Its Effect on Chemical Mechanical Polishing

Junning Chen,Shibin Lu,Haibo Wang,Ying Meng,Feifei Wang,Min Fan 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

Introduction: Chemical mechanical polishing is the only one technology to obtain global planarization, which is widely applied to polish silicon, copper dual damascene structure, high/low K dielectric materials, tungsten plugs, poly-silicon gates and shallow trench isolation structure. SiO2 is widely used as abrasive for its superior properties like stability, suspension property and low viscosity There are lots of studies on silica properties. However, the detailed silica surface, inner characteristic and its effect on polishing performance are still unclear. we must also explore the silica nano-particle tiny structure difference, so we designed an experiment that we anneal the colloid silica and re-dispersed it to analyze the variety of particles properties and its influences on CMP performance. Materials: The water glass was purchased from the market. KOH (90%) and H2SO4 (98%) were purchased commercially from Shanghai Aladdin Bio-Chem technology Co., Ltd. All reagents were of analytical grade and used without further purification. Method: Diluted KOH or H2SO4 were added to 1 wt% annealed silica slurry to adjust pH value to 11.0. The slurry was milled in the polishing process. Arsenic doped 4 inch (100) silicon wafer was used to polish. The structural and morphological evolution of silica nano-particles induced by heat treatment are studied by scanning electron microscopy (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), differential thermal (DTA) and thermal gravimetric analysis (TGA), which disclose the external and internal structure.

Development of a Malignancy Potential Binary Prediction Model Based on Deep Learning for the Mitotic Count of Local Primary Gastrointestinal Stromal Tumors

Yang Jiejin,Chen Zeyang,Liu Weipeng,Wang Xiangpeng,Ma Shuai,Jin Feifei,Wang Xiaoying 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.3

Objective: The mitotic count of gastrointestinal stromal tumors (GIST) is closely associated with the risk of planting and metastasis. The purpose of this study was to develop a predictive model for the mitotic index of local primary GIST, based on deep learning algorithm. Materials and Methods: Abdominal contrast-enhanced CT images of 148 pathologically confirmed GIST cases were retrospectively collected for the development of a deep learning classification algorithm. The areas of GIST masses on the CT images were retrospectively labelled by an experienced radiologist. The postoperative pathological mitotic count was considered as the gold standard (high mitotic count, > 5/50 high-power fields [HPFs]; low mitotic count, ≤ 5/50 HPFs). A binary classification model was trained on the basis of the VGG16 convolutional neural network, using the CT images with the training set (n = 108), validation set (n = 20), and the test set (n = 20). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at both, the image level and the patient level. The receiver operating characteristic curves were generated on the basis of the model prediction results and the area under curves (AUCs) were calculated. The risk categories of the tumors were predicted according to the Armed Forces Institute of Pathology criteria. Results: At the image level, the classification prediction results of the mitotic counts in the test cohort were as follows: sensitivity 85.7% (95% confidence interval [CI]: 0.834–0.877), specificity 67.5% (95% CI: 0.636–0.712), PPV 82.1% (95% CI: 0.797–0.843), NPV 73.0% (95% CI: 0.691–0.766), and AUC 0.771 (95% CI: 0.750–0.791). At the patient level, the classification prediction results in the test cohort were as follows: sensitivity 90.0% (95% CI: 0.541–0.995), specificity 70.0% (95% CI: 0.354–0.919), PPV 75.0% (95% CI: 0.428–0.933), NPV 87.5% (95% CI: 0.467–0.993), and AUC 0.800 (95% CI: 0.563–0.943). Conclusion: We developed and preliminarily verified the GIST mitotic count binary prediction model, based on the VGG convolutional neural network. The model displayed a good predictive performance.

Experimental Investigation of Crack PropagationMechanism and Load-bearing Characteristics for Anti-slide Pile

Qingyang Ren,Feifei Wang,Xiaofeng Lin,Bin Chen,Xiangwei Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.6

Reinforced concrete anti-slide pile is a typical anti-slide installation under horizontal load. Its stress is essentially the cantilever beam working under the combined action of bending moment and shear force. In the process of loading, concrete is accompanied by the generation and expansion of different forms of cracks. In order to reveal the bearing characteristics and crack propagation law of anti-slide pile, the 1:10 scale model of the anti-slide pile in Majiagou landslide treatment project was taken as the object. The mechanical mechanisms of three kinds of the anti-slide piles with different pile lengths were studied. The bending moment and deformation law of three anti-slide piles were obtained. The results show that the pile is easy to crack in the range of 0.5 m above and below the sliding surface. With the increase of cantilever length, the bending moment increases. The development of the maximum crack length and width presents the crack initiation stage, stable stage, and failure mutation stage. Through the monitoring of the length and width of the crack and the judgment of its stage, the working state of the pile can be obtained. The results can provide reference for the optimal design of anti-slide pile in landslide treatment engineering.

Lactobacillus rhamnosus CCFM1107 treatment ameliorates alcohol -induced liver injury in a mouse model of chronic alcohol feeding

Fengwei Tian,Feifei Chi,Gang Wang,Xiaoming Liu,Qiuxiang Zhang,Yongquan Chen,Hao Zhang,Wei Chen 한국미생물학회 2015 The journal of microbiology Vol.53 No.12

Lactobacillus rhamnosus CCFM1107 was screened for high antioxidative activity from 55 lactobacilli. The present study attempted to explore the protective properties of L. rhamnosus CCFM1107 in alcoholic liver injury. A mouse model was induced by orally feeding alcohol when simultaneously treated with L. rhamnosus CCFM1107, the drug Hu-Gan- Pian (HGP), L. rhamnosus GG (LGG), and L. plantarum CCFM1112 for 3 months. Biochemical analysis was performed for both serum and liver homogenate. Detailed intestinal flora and histological analyses were also carried out. Our results indicated that the administration of L. rhamnosus CCFM1107 significantly inhibited the increase in the levels of serum aminotransferase and endotoxin, as well as the levels of triglyceride (TG) and cholesterol (CHO) in the serum and in the liver. Glutathione (GSH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were elevated while the levels of malondialdehyde (MDA) were decreased. The enteric dysbiosis caused by alcohol was restored by increasing the numbers of both lactobacilli and bifidobacteria and decreasing the numbers of both enterococci and enterobacter. Histological analysis confirmed the protective effect of L. rhamnosus CCFM1107. Compared with the other lactobacilli and to the drug Hu-Gan-Pian, there is a high chance that L. rhamnosus CCFM1107 provides protective effects on alcoholic liver injury by reducing oxidative stress and restoring the intestinal flora.

Thermal Model for Power Converters Based on Thermal Impedance

Xu, Yang,Chen, Hao,Lv, Sen,Huang, Feifei,Hu, Zhentao The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

In this paper, the superposition principle of a heat sink temperature rise is verified based on the mathematical model of a plate-fin heat sink with two mounted heat sources. According to this, the distributed coupling thermal impedance matrix for a heat sink with multiple devices is present, and the equations for calculating the device transient junction temperatures are given. Then methods to extract the heat sink thermal impedance matrix and to measure the Epoxy Molding Compound (EMC) surface temperature of the power Metal Oxide Semiconductor Field Effect Transistor (MOSFET) instead of the junction temperature or device case temperature are proposed. The new thermal impedance model for the power converters in Switched Reluctance Motor (SRM) drivers is implemented in MATLAB/Simulink. The obtained simulation results are validated with experimental results. Compared with the Finite Element Method (FEM) thermal model and the traditional thermal impedance model, the proposed thermal model can provide a high simulation speed with a high accuracy. Finally, the temperature rise distributions of a power converter with two control strategies, the maximum junction temperature rise, the transient temperature rise characteristics, and the thermal coupling effect are discussed.