Failure Mechanism of Face for Slurry Shield-Driven Tunnel in Sand

Handong Liu,Yafeng Zhang,Haining Liu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.10

To achieve the failure mechanism of face for slurry shield tunnel in sand stratum, a model test device for shield excavation with ideal slurry film was developed. The active failure processes of tunnel excavation face in dry sand stratum for different densities and cover depths were achieved through model test and two-dimensional particle flow code (PFC2D). Furthermore, soil deformation, failure mode and soil arching effect of tunnel excavation face were revealed. The results show that the face deformation can be divided into three stages in relation to the support pressure and the excavation face has been failed in third stage. The density of sand has a great influence on the failure mode of excavation face. The failure mode in dense condition is a combination of a wedge with slip arc and a prism chimney, while in loose condition it is a relatively dispersed “trumpet” shape failure zone. However, the cover depth has a negligible effect on the failure mode. In dense sand stratum, a loose failure zone was formed in front of the excavation face and a soil arch was formed above it. The soil arch developed continuously above the tunnel crown to the ground surface. The limit support pressure calculated by PFC2D (two-dimensional particle flow code) increases with the cover depth, which is consistent with the observations in model tests.

Indoor feeding combined with restricted grazing time improves body health, slaughter performance, and meat quality in Huang-huai sheep

Huang Yafeng,Zhao Mengyu,Zhang Xiaoan,Wei Huiqing,Liu Lumeng,Zhang Zi Jun,Cheng Xiao,Wang Guanjun,Ren Chunhuan 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.11

Objective: The aim of this study was to evaluate the effects of three feeding systems, i.e., indoor feeding (CON), indoor feeding with 4-h daily access to grazing artificial pasture (ITGP), and indoor feeding with 8-h daily access to grazing artificial pasture (IEGP), on the plasma antioxidant and immunological capacity, slaughter characteristics, meat quality and economic efficiency of Huang-huai lambs. Methods: Thirty-three healthy Huang-huai rams with similar body weight (approximately 5 mo of age, 28.96±1.01 kg) were assigned equally to three experimental groups. When finished fattening, six lambs from each group were collect blood samples for plasma analyses and then slaughtered to determine slaughter characteristics and obtain biceps brachii muscle for further analysis of meat quality and fatty acid profile. Results: Compared to CON group, animals submitted to ITGP and IEGP groups resulted in greater contents of serum glutathione peroxidase, immunoglobulins (IgA, IgG, and IgM), polyunsaturated fatty acids (PUFA), n-6 PUFA, and PUFA/saturated fatty acid (FA) ratio and lower palmitic /oleic acid ratio (p<0.05). Moreover, animals in ITGP group exhibited a higher (p<0.05) loin eye area, content of meat crude protein (CP), and eicosetrienoic acid compared to CON group, while slaughter performance was superior (p<0.05) to that of the IEGP group. The economic efficiency of ITGP group was 70.12% higher than that of CON group, while the IEGP group exhibited a decrease of 92.54% in economic efficiency compared to the CON group. Conclusion: Restricted grazing time combined with indoor feeding was more effective in conferring superior body health, carcass traits and economic efficiency in Huang-huai lambs, as well as higher CP content and healthier FA composition in the resulting meat.

Visual Attention Model Based on Particle Filter

( Long Liu ),( Wei Wei ),( Xianli Li ),( Yafeng Pan ),( Houbing Song ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8

The visual attention mechanism includes 2 attention models, the bottom-up (B-U) and the top-down (T-D), the physiology of which have not yet been accurately described. In this paper, the visual attention mechanism is regarded as a Bayesian fusion process, and a visual attention model based on particle filter is proposed. Under certain particular assumed conditions, a calculation formula of Bayesian posterior probability is deduced. The visual attention fusion process based on the particle filter is realized through importance sampling, particle weight updating, and resampling, and visual attention is finally determined by the particle distribution state. The test results of multigroup images show that the calculation result of this model has better subjective and objective effects than that of other models.

Feeding regimens affecting carcass and quality attributes of sheep and goat meat — A comprehensive review

Huang Yafeng,Liu Lumeng,Zhao Mengyu,Zhang Xiaoan,Chen Jiahong,Zhang Zi Jun,Cheng Xiao,Ren Chunhuan 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.9

Sheep and goats can efficiently convert low quality forage into high-quality meat which contains specific nutrients and quality traits. Carcass traits and quality attributes of sheep and goat meat depend upon several factors and one of most effective strategies amongst these is feeding regimens. In this review, the major aspects of feeding regimens affecting growth rate, carcass traits and quality attributes of sheep and goat meat are thoroughly discussed, with a particular focus on physical-chemical composition, flavor profile, and fatty acid (FA) profile. Grazing lambs and kids receiving concentrate or under stall-feeding systems had greater average daily gain and carcass yield compared with animals reared on pasture only. However, growth rate was higher in lambs/kids grazing on pastures of improved quality. Moreover, the meat of grazing lambs receiving concentrate had more intense flavor, intramuscular fat (IMF) content, and unhealthy FA composition, but comparable color, tenderness, juiciness, and protein content compared to that of lambs grazed on grass only. In contrast, meat of concentrate-fed lambs had more intense color, greater tenderness and juiciness, IMF and protein contents, and lower flavor linked to meat. Additionally, the meat of kids grazed on concentrate supplementation had higher color coordinates, tenderness, IMF content and unhealthy FA composition, whereas juiciness and flavor protein content were similar. In contrast, kids with concentrate supplementation had superior color coordinates, juiciness, IMF content and unhealthy FA composition, but lower tenderness and flavor intensity compared to pasture-grazed kids. Thus, indoor-finished or supplemented grazing sheep/goats had higher growth rate and carcass quality, higher IMF content and unhealthy FA composition compared to animals grazed on grass only. Finally, supplementation with concentrate increased flavor intensity in lamb meat, and improved color and tenderness in kid meat, whereas indoor-fed sheep/goats had improved color and juiciness as well as reduced flavor compared to pasture-grazed animals.

An engineered PD-1-based and MMP-2/9-oriented fusion protein exerts potent antitumor effects against melanoma

( Mulan Wei ),( Xujie Liu ),( Chunyu Cao ),( Jianlin Yang ),( Yafeng Lv ),( Jiaojiao Huang ),( Yanlin Wang ),( Ye Qin ) 생화학분자생물학회 2018 BMB Reports Vol.51 No.11

Recent studies showed that the PD-1/PD-L1 checkpoint blockade is a dramatic therapy for melanoma by enhancing antitumor immune activity. Currently, major strategies for the PD-1/PD-L1 blockade have mainly focused on the use of antibodies and compounds. Seeking an alternative approach, others employ endogenous proteins as blocking agents. The extracellular domain of PD-1 (ePD1) includes the binding site with PD-L1. Accordingly, we constructed a PD-1-based recombinantly tailored fusion protein (dFv-ePD1) that consists of bivalent variable fragments (dFv) of an MMP-2/9-targeted antibody and ePD1. The melanoma-binding intensity and antitumor activity were also investigated. We found the intense and selective binding capability of the protein dFv-ePD1 to human melanoma specimens was confirmed by a tissue microarray. In addition, dFv-ePD1 significantly suppressed the migration and invasion of mouse melanoma B16-F1 cells, and displayed cytotoxicity to cancer cells in vitro. Notably, dFv-ePD1 significantly inhibited the growth of mouse melanoma B16-F1 tumor cells in mice and in vivo fluorescence imaging showed that dFv-ePD was gradually accumulated into the B16-F1 tumor. Also the B16-F1 tumor fluorescence intensity at the tumor site was stronger than that of dFv. This study indicates that the recombinant protein dFv-ePD1 has an intensive melanoma-binding capability and exerts potent therapeutic efficacy against melanoma. The novel format of the PD-L1-blocked agent may play an active role in antitumor immunotherapy. [BMB Reports 2018; 51(11): 572-577]

Free Vibration of the Cracked Non-uniform Beam with Cross Section Varying as Polynomial Functions

Guo-jin Tan,Yang Liu,Yafeng Gong,Yangfan Shen,Ziyu Liu 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.11

This paper presents an approach for free vibration analysis of the cracked non-uniform beam with general boundary conditions, whose mass per unit length and bending moment of inertia varying as polynomial functions. Firstly, the general expression of mode shape function of the non-uniform beam with four undetermined coefficients is solved by a generalized power series method based on the Euler-Bernoulli beam theory. Then, the transfer matrix method is combined into the mode shape function of the non-uniform beam to improve the computational efficiency owe to the fewer segments divided by the cracks and joints at the different forms of variable cross-section. The massless rotational springs are adopted to simulate the cracks to derive the transfer relationship of the undetermined coefficients in the same segment. The four undetermined coefficients matrix is obtained by using equilibrium and continuity conditions between two adjacent segments, and then the characteristic equation of the entire cracked beam is formed. Finally, the correctness and reliability of the proposed method in this paper is verified by the methods presented by other published papers and the Finite Element Method (FEM). In addition, the crack parameters on the vibratory characteristics are investigated through the numerical examples.

Preparation of corn straw based spongy aerogel for spillage oil capture

Yuan Li,Xiaodong Liu,Weijie Cai,Yafeng Cao,Yanfeng Sun,Fengzhi Tan 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5

This work mainly focused on the preparation of a low-cost, ultralight absorbent from renewable corn straw and filter paper via a facile and environmental-friendly approach containing high-shear blending and freeze-drying operation. The physicochemical properties of aerogel were thoroughly examined by several characterization techniques. The satisfactory hydrophobicity of the spongy aerogel was attributed to the formation of polysiloxane on the surface of methyltrimethoxysilane (MTMS) by the silanization reaction. Owing to its superior features, such as ultralow density, high porosity, desirable hydrophobicity, the corn straw based spongy aerogel exhibited a remarkable absorption capacity for both crude oil (36 g/g) and common organic solvents including carbon tetrachloride (CCl4, 45 g/g), dimethyl sulphoxide (DMSO, 24 g/g), N, N-dumethylformamide (DMF, 45 g/g). This might shed light on the design of efficient adsorbent for oil spills and organic pollutants to meet with the sustainable development.

Efficiently targeted therapy of glioblastoma xenograft via multifunctional biomimetic nanodrugs

Zhipeng Yao,Xiaochun Jiang,Hong Yao,Yafeng Wu,Fan Zhang,Cheng Wang,Chenxue Qi,Chenhui Zhao,Zeyu Wu,Min Qi,Jia Zhang,Xiaoxiang Cao,Zhichun Wang,Fei Wu,Chengyun Yao,Songqin Liu,Shizhang Ling,Hongping Xi 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

Background: Glioblastoma multiforme (GBM) is a fatal malignant primary brain tumor in adults. The therapeutic efficacy of chemotherapeutic drugs is limited due to the blood-brain barrier (BBB), poor drug targeting, and short biological half-lives. Multifunctional biomimetic nanodrugs have great potential to overcome these limitations of chemotherapeutic drugs. Methods: We synthesized and characterized a biomimetic nanodrug CMS/PEG-DOX-M. The CMS/PEG-DOX-M effectively and rapidly released DOX in U87 MG cells. Cell proliferation and apoptosis assays were examined by the MTT and TUNEL assays. The penetration of nanodrugs through the BBB and anti-tumor efficacy were investigated in the orthotopic glioblastoma xenograft models. Results: We showed that CMS/PEG-DOX-M inhibited cell proliferation of U87 MG cells and effectively induced cell apoptosis of U87 MG cells. Intracranial antitumor experiments showed that free DOX hardly penetrated the BBB, but CMS/PEG-DOX-M effectively reached the orthotopic ntracranial tumor through the BBB and significantly inhibited tumor growth. Immunofluorescence staining of orthotopic tumor tissue sections confirmed that nanodrugs promoted apoptosis of tumor cells. This study developed a multimodal nanodrug treatment system with the enhanced abilities of tumor-targeting, BBB penetration, and cancer-specific accumulation of chemotherapeutic drugs by combining chemotherapy and photothermal therapy. It can be used as a flexible and effective GBM treatment system and it may also be used for the treatment of other central nervous systems (CNS) tumors and extracranial tumors.

Molecular cloning and expression analysis of the first two key genes through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway from Pyropia haitanensis (Bangiales, Rhodophyta)

Du, Yu,Guan, Jian,Xu, Ruijun,Liu, Xin,Shen, Weijie,Ma, Yafeng,He, Yuan,Shen, Songdong The Korean Society of Phycology 2017 ALGAE Vol.32 No.4

Pyropia haitanensis (T. J. Chang et B. F. Zheng) N. Kikuchi et M. Miyata is one of the most commercially useful macroalgae cultivated in southeastern China. In red algae, the biosynthesis of terpenoids through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway can produce a direct influence on the synthesis of many biologically important metabolites. In this study, two genes of cDNAs, 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-D-xylulose-5-phosphate reductase (DXR), which encoding the first two rate-limiting enzymes among MEP pathway were cloned from P. haitanensis. The cDNAs of P. haitanensis DXS (PhDXS) and DXR (PhDXR) both contained complete open reading frames encoding polypeptides of 764 and 426 amino acids residues, separately. The expression analysis showed that PhDXS was significant differently expressed between leafy thallus and conchocelis as PhDXR been non-significant. Additionally, expression of PhDXR and its downstream gene geranylgeranyl diphosphate synthase were both inhibited by fosmidomycin significantly. Meanwhile, we constructed types of phylogenetic trees through different algae and higher plants DXS and DXR encoding amino acid sequences, as a result we found tree clustering consequences basically in line with the "Cavalier-Smith endosymbiotic theory." Whereupon, we speculated that in red algae, there existed only complete MEP pathway to meet needs of terpenoids synthesis for themselves; Terpenoids synthesis of red algae derivatives through mevalonate pathway came from two or more times endosymbiosis of heterotrophic eukaryotic parasitifer. This study demonstrated that PhDXS and PhDXR could play significant roles in terpenoids biosynthesis at molecular levels. Meanwhile, as nuclear genes among MEP pathway, PhDXS and PhDXR could provide a new way of thinking to research the problem of chromalveolata biological evolution.

Molecular cloning and expression analysis of the first two key genes through 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway from Pyropia haitanensis(Bangiales, Rhodophyta)

Yu Du,Jian Guan,Ruijun Xu,Xin Liu,Weijie Shen,Yafeng Ma,Yuan He,Songdong Shen 한국조류학회I 2017 ALGAE Vol.32 No.4

Pyropia haitanensis (T. J. Chang et B. F. Zheng) N. Kikuchi et M. Miyata is one of the most commercially usefulmacroalgae cultivated in southeastern China. In red algae, the biosynthesis of terpenoids through 2-C-methyl-Derythritol4-phosphate (MEP) pathway can produce a direct influence on the synthesis of many biologically importantmetabolites. In this study, two genes of cDNAs, 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and 1-deoxy-Dxylulose-5-phosphatereductase (DXR), which encoding the first two rate-limiting enzymes among MEP pathway werecloned from P. haitanensis. The cDNAs of P. haitanensis DXS (PhDXS) and DXR (PhDXR) both contained complete openreading frames encoding polypeptides of 764 and 426 amino acids residues, separately. The expression analysis showedthat PhDXS was significant differently expressed between leafy thallus and conchocelis as PhDXR been non-significant. Additionally, expression of PhDXR and its downstream gene geranylgeranyl diphosphate synthase were both inhibitedby fosmidomycin significantly. Meanwhile, we constructed types of phylogenetic trees through different algae and higherplants DXS and DXR encoding amino acid sequences, as a result we found tree clustering consequences basically in linewith the "Cavalier-Smith endosymbiotic theory." Whereupon, we speculated that in red algae, there existed only completeMEP pathway to meet needs of terpenoids synthesis for themselves; Terpenoids synthesis of red algae derivativesthrough mevalonate pathway came from two or more times endosymbiosis of heterotrophic eukaryotic parasitifer. Thisstudy demonstrated that PhDXS and PhDXR could play significant roles in terpenoids biosynthesis at molecular levels. Meanwhile, as nuclear genes among MEP pathway, PhDXS and PhDXR could provide a new way of thinking to researchthe problem of chromalveolata biological evolution.