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  • Open Access

    ABSTRACT

    Virtual Implantation of Stent-graft by Finite Element Simulation and Its Applications in Endovascular Treatment Planning for B Type Aortic Dissection

    Zhuanyuan Meng1, Tao Ma2, Zhihui Dong2, Shengzhang Wang1,*, Weiguo Fu2

    Molecular & Cellular Biomechanics, Vol.16, Suppl.2, pp. 60-60, 2019, DOI:10.32604/mcb.2019.07253

    Abstract Thoracic endovascular aortic repair has been widely applied to treat Stanford Type B aortic dissection. However, retrograde type A dissection can occur as a complication after thoracic endovascular repair for Stanford type B aortic dissection. In order to investigated the possible mechanical reasons of the new entry occurring when stent grafts were implanted into the true lumen of one type B aortic dissection, a framework of virtual implantation of stent-graft by using finite element simulations was developed in this paper. The animal experiments were adopted to verify the finite element simulation of stent-graft implantation. Moreover, the manufactured stent-grafts were implanted… More >

  • Open Access

    ABSTRACT

    Effect of Ultrafine Nano-Zinc Particles on Cardiac Structure and Function in Myocardial Infarction Rabbits

    Pei Niu1, Li Li1, Yufan Huang2, Yunlong Huo3,*

    Molecular & Cellular Biomechanics, Vol.16, Suppl.1, pp. 45-45, 2019, DOI:10.32604/mcb.2019.05724

    Abstract Due to ultrafine Nano-zinc particles are major component of PM0.1, so we aimed to investigate how ultrafine Nano-zinc particles effect on cardiac structure and function in myocardial infarction (MI) rabbits. We chose twenty-four New Zealand rabbits who were divided into sham group, MI group and MI exposure group randomly, 8 rabbits in each group. We preformed LAD ligation operation in MI group and MI exposure group. After two weeks rabbits suffered from MI successfully, we put the MI exposure group into ventilation chamber filled with 500 ug/m3 ultrafine Nano-zinc particles for 6 hours per day. Sham group and MI group… More >

  • Open Access

    ARTICLE

    Evaluation of Stress Environment around Pits in Nickel Aluminum Bronze Metal under Corrosion and Cyclic Stresses

    Ramana M. Pidaparti1, Alex C. Johnson1

    Structural Durability & Health Monitoring, Vol.9, No.1, pp. 87-98, 2013, DOI:10.32604/sdhm.2013.009.087

    Abstract Surface damage in the form of pitting was observed in NiAl Bronze metal subjected to corrosion and cyclic stresses. In order to investigate the stresses surrounding the evolving pits due to corrosion, an image based computational study was carried out. The computational study involves developing an analysis model from the SEM images of corroded pits and then conducting stress analysis. Several computational simulations were carried out with increasing/evolving pits and the corresponding stress environment was obtained. The results obtained indicate that pit profiles (size and height) greatly affect the stress environment and the maximum stresses may vary depending on the… More >

  • Open Access

    ARTICLE

    Brillouin Spectral Response Depending on Strain Non-Uniformity within Centimeter Spatial Resolution and its Application to Internal Damage Detection in Large-Scale Composite Structures

    Shu Minakuchi1, Tadahito Mizutani1, Haruka Tsukamoto2, Mayuko Nishio2, Yoji Okabe3, Nobuo Takeda1

    Structural Durability & Health Monitoring, Vol.4, No.4, pp. 199-220, 2008, DOI:10.3970/sdhm.2008.004.199

    Abstract The authors propose a technique to detect centimeter internal damages in large-scale composite structures, using an optical fiber network running throughout the structure. A Brillouin-based distributed strain sensing system with centimeter-order spatial resolution (pre-pump pulse Brillouin optical time domain analysis (PPP-BOTDA)) was utilized to detect residual non-uniform strain in the damaged area. First, Brillouin spectral response depending on the strain profile within the spatial resolution was revealed. The spectral response depending on strain non-uniformity was experimentally quantified with consideration of the general characteristics of the Brillouin gain spectrum. Then, the damage detection procedure was proposed, based on the spectral response.… More >

  • Open Access

    ARTICLE

    Sensitivity of Eigen Value to Damage and Its Identification

    B.K.Raghuprasad1, N.Lakshmanan2, N.Gopalakrishnan2, K.Muthumani2

    Structural Durability & Health Monitoring, Vol.4, No.3, pp. 117-144, 2008, DOI:10.3970/sdhm.2008.004.117

    Abstract The reduction in natural frequencies, however small, of a civil engineering structure, is the first and the easiest method of estimating its impending damage. As a first level screening for health-monitoring, information on the frequency reduction of a few fundamental modes can be used to estimate the positions and the magnitude of damage in a smeared fashion. The paper presents the Eigen value sensitivity equations, derived from first-order perturbation technique, for typical infra-structural systems like a simply supported bridge girder, modelled as a beam, an end-bearing pile, modelled as an axial rod and a simply supported plate as a continuum… More >

  • Open Access

    ARTICLE

    On the Estimation of Notch Fatigue Limits by Using the Theory of Critical Distances: L, a0 and Open Notches

    L. Susmel1,2, D. Taylor2, R. Tovo1

    Structural Durability & Health Monitoring, Vol.4, No.1, pp. 1-18, 2008, DOI:10.3970/sdhm.2008.004.001

    Abstract This paper investigates some theoretical aspects related to the use of the Theory of Critical Distances (TCD) when employed to estimate notch fatigue limits. The linear-elastic TCD takes as a starting point the hypothesis that notched components are in their fatigue limit condition when an effective stress, whose value depends on a characteristic length, equals the material plain fatigue limit. Such an idea can be formalised by following different strategies: either assuming that the effective stress depends only on the profile of the stress field damaging the fatigue process zone and the reference distance is a material property or assuming… More >

  • Open Access

    ARTICLE

    Analysis of Noise Sources Produced by Faulty Small Gear Units

    Aleš Belšak1, Jurij Prezelj2

    Structural Durability & Health Monitoring, Vol.3, No.4, pp. 239-246, 2007, DOI:10.3970/sdhm.2007.003.239

    Abstract Noise source vizualization represents an important tool in the field of technical acoustics. There are many different techniques of noise source visualization. Most of them, however, are intended for a specific noise source in a specific type of acoustic environment. Consequently, a certain visualization method can be used only for certain types of noise sources in a specific acoustic environment and in a restricted frequency area. This paper presents a new visualization method of complex noise sources on the basis of the use of an acoustic camera. A new algorithm has been used, which makes it possible to visualize all… More >

  • Open Access

    ARTICLE

    Carcinoembryonic antigen inhibits neutrophil activation by N-formyl-methionyl-leucyl-phenylalanine

    Anna PAŃCZYSZYN1 *, Anna KROP-WATOREK1,2, Maciej WIECZOREK1

    BIOCELL, Vol.39, No.2-3, pp. 1-4, 2015, DOI:10.32604/biocell.2015.39.001

    Abstract Carcinoembryonic antigen (CEA) is a surface glycoprotein expressed in human epithelial cells and is released from their surface, especially during colorectal cancer. Frequently, colorectal cancer is accompanied by inflammation, where tumor-infiltrating neutrophils play an important role. CEA was also found to be a strong chemotactic agent for neutrophils. The purpose of this study was to find out if CEA can enhance neutrophil priming and activation. Primed neutrophils were activated by N-formyl-methionyl-leucyl-phenylalanine (formyl-MLP) and the resulting oxidative burst was measured luminometrically. Unexpectedly, in vitro priming of neutrophils by CEA, alone or preceded by LPS, inhibited subsequent activation of these cells by… More >

  • Open Access

    ARTICLE

    Adenosine A1 receptor activation inhibits histamine release in gastric enterochromaffin-like cells

    Rafael Martins de OLIVEIRA, Carolina Bernardi STEFANI, Angélica Aparecida Antoniellis SILVEIRA, Marcelo Lima RIBEIRO, José PEDRAZZOLI Jr., Alessandra GAMBERO*

    BIOCELL, Vol.39, No.2-3, pp. 5-8, 2015, DOI:10.32604/biocell.2015.39.005

    Abstract Adenosine acts as a gastroprotective factor decreasing inflammation and reducing gastric acid secretion. Quantitative RT-PCR was used to determine the expression of the adenosine receptor genes (A1AR, A2AAR, A2BAR and A3AR) and that of the gastrin receptor B gene (CCKBR) in isolated, short-term cultured enterochromaffin-like (ECL) cells. Both the A1AR and the CCKBR genes were expressed at a level higher than the other genes. Also, the effect of 2-chloroadenosine, a stable agonist of A1 and A2A receptors, was explored on ECL cells, with a resulting inhibition of both basal and gastrin-stimulated histamine release. Also, dipropylcyclopentylxanthine (DPCPX), a selective A1 antagonist,… More >

  • Open Access

    ARTICLE

    Finite Element Investigation of Flow Field Below Asymmetric Drill Bits for Reverse Circulation in Drilling Tight Oil and Gas Reservoirs

    Yi Luo1,*, Erxiu Shi2, Yin Feng2, Boyun Guo2, Liehui Zhang1

    CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.1, pp. 105-122, 2019, DOI:10.32604/cmes.2019.06500

    Abstract Development of unconventional tight oil and gas reservoirs such as shale pays presents a huge challenge to the petroleum industry due to the naturally low permeability of shale formations and thus low productivity of oil and gas wells. Shale formations are also vulnerable to the contamination of the water in the drilling and completion fluids, which further reduces reservoir permeability. Although gas-drilling (drilling with gas) has been used to address the issue, several problems such as formation water influx, wellbore collapse, excessive gas volume requirement and hole cleaning in horizontal drilling, still hinder its application. A new technique called gas-lift… More >

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