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  • Open Access

    ARTICLE

    Chlorination: Phytotoxicity and effects on the production and quality of Lactuca sativa var. Mantecosa grown in a closed, soil-less system

    Premuzic1 Z, HE Palmucci1, J Tamborenea1, M Nakama2

    Phyton-International Journal of Experimental Botany, Vol.76, pp. 103-117, 2007, DOI:10.32604/phyton.2007.76.103

    Abstract The addition of chlorine constitutes an economical disinfection method for closed, soil-less systems. Three quantities of sodium hypochlorite (0.55, 5.5 and 11 ppm) were applied to closed, soil-less greenhouse- grown lettuce (Lactuca sativa), to study the effect on its production (fresh weight and dry matter) and some commercial and nutritional quality factors (phytotoxicity, Vitamin C, nitrates). Sodium hypochlorite was weekly added within the nutrient solution, and the chemical properties (pH, EC and chlorides) of the recycled solution were measured. Damage to leaves was evaluated 15 days before harvest. Chlorination produced different effects regarding both production and… More >

  • Open Access

    ARTICLE

    Technical Note : Prolonged exposure of human embryonic stem cells to heat shock induces necrotic cell death

    B.C. Heng*, K.J. Vinoth*, K. Lu*, X. Deng*, Z. Ge*, B.H. Bay**, T. Cao*

    BIOCELL, Vol.31, No.3, pp. 405-410, 2007, DOI:10.32604/biocell.2007.31.405

    Abstract We investigated the effects of prolonged heat shock treatment on human embryonic stem cell (hESC) viability. The hESC viability steadily declined with longer exposure to heat shock treatment (43ºC). After 4 h of exposure to heat shock at 43ºC, only 56.2 ± 1.5% of cells were viable. Viability subsequently declined to 37.0 ± 3.3% and 3.5 ± 0.7% after 8 h and 16 h, respectively of heat shock treatment at 43ºC. Transmission electron micrographs showed that the morphology of the dead/dying cells after heat shock treatment was characteristic of cellular necrosis with an uncondensed chromatin… More >

  • Open Access

    ARTICLE

    Immunophenotypic evaluation, and physiological and laboratory correlations of hematopoietic stem cells from umbilical cord blood

    R. Canabarro1,2, H. Sporleder2, T. Gomes3,4, G. Zanatta3,5, L. Scribel3,6, F. Freitas7, J. Neumann2, P. Pranke1,3

    BIOCELL, Vol.31, No.3, pp. 397-403, 2007, DOI:10.32604/biocell.2007.31.397

    Abstract The use of umbilical cord blood stem cells is an efficient alternative for the transplantation of hematopoietic progenitor cells. A number of factors can influence the volume and amount of CD34+ cells, which are considered as immature and capable of proliferation. Quantification of CD34+ cells, evaluation of CD38 and c-kit molecules on these cells, as well as correlations of such factors as maternal age, gestational age, newborn sex and weight, umbilical cord length, placental weight with increased volume and concentration of immature cells, among others, were performed in 70 blood samples from term newborns. The mean… More >

  • Open Access

    ARTICLE

    An Investigation into Active Strain Transfer Analysis in a Piezoceramic Sensor System for Structural Health Monitoring Using the Dual Boundary Element Method

    S.P.L. Leme1, M.H. Aliabadi2, L.M. Bezerra1, P.W. Partridge1

    Structural Durability & Health Monitoring, Vol.3, No.3, pp. 121-132, 2007, DOI:10.3970/sdhm.2007.003.121

    Abstract The coupled electromechanical behaviour of a thin piezoceramic sensor bonded to a stiffened panel subjected to membrane mechanical loadings is examined. The sensor is characterised by an electrostatic line model bonded to a damaged panel modelled by the dual boundary element method. Numerical results obtained demonstrate that the proposed method is capable of modelling changes in the signal output due to presence of cracks. Also presented is a numerical model for detecting fatigue crack growth in a stiffened panel using piezoceramic sensors. More >

  • Open Access

    ARTICLE

    Integrity of Thermal Actuators using the Concept of Energy Density

    C.P. Providakis1

    Structural Durability & Health Monitoring, Vol.3, No.1, pp. 29-34, 2007, DOI:10.3970/sdhm.2007.003.029

    Abstract Actuators are structures that give micro-electro-mechanical systems (MEMS) the ability to interact with their environment rather than just passively sensing it. Recent studies of MEMS thermal micro-actuators have shown that simple in design and production devices can provide deflection of the order of 10 μm at low voltages. Recently, metals and single-crystal silicon materials were included in the range of materials used for thermal actuators since they operate at lower temperatures than the commonly used (poly)silicon devices. These actuators are liable to meet the loads in service, so the corresponding integrity and stability analysis constitutes a… More >

  • Open Access

    ABSTRACT

    H-matrix preconditioners for saddle-point systems from meshfree discretization 1

    Suely Oliveira2, Fang Yang2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.2, pp. 113-120, 2007, DOI:10.3970/icces.2007.003.113

    Abstract In this paper we describe and compare preconditioners for saddle-point systems obtained from meshfree discretizations, using the concepts of hierarchical (or H-)matrices. Previous work by the authors using this approach did not use H-matrix techniques throughout, as is done here. Comparison shows the method described here to be better than the author's previous method, an AMG method adapted to saddle point systems, and conventional iterative methods such as JOR. More >

  • Open Access

    ABSTRACT

    About the POD Model Reduction in Computational Mechanics for Nonlinear Continuous Dynamical Systems

    R. Sampaio1, C. Soize2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.4, pp. 93-100, 2007, DOI:10.3970/icces.2007.002.093

    Abstract An analysis of the efficiency of the reduced models constructed using the POD-basis and the LIN-basis is presented in nonlinear dynamics for continuous elastic systems discretized by the finite element method. The POD-basis is the basis constructed with the POD method while the LIN-basis is the basis derived from the generalized eigenvalue problem associated with the underlying linear conservative part of the system and usually called the eigenmodes of vibration. The efficiency of the POD-basis or the LIN-basis is related to the speed of convergence in the frequency domain of the solution constructed with the More >

  • Open Access

    ABSTRACT

    An e-learning system for CAE

    A. Kuwata1, H. Noguchi2, H. Kawai3

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.3, pp. 87-92, 2007, DOI:10.3970/icces.2007.002.087

    Abstract In this research, we constructed an e-learning system of the CAE (FEM) education. We analyzed about the usefulness of e-learning from each viewpoint of a software developer of the e-learning system, a system administrator of the system, and a user. In addition, we considered about the necessary technology in Web application. More >

  • Open Access

    ABSTRACT

    Shape Sensitivity Analysis of Bioheat Transfer in the System Blood Vessel - Surrounding Tissue

    Bohdan Mochnacki1, Grażyna Kaluża2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.1, pp. 15-20, 2007, DOI:10.3970/icces.2007.001.015

    Abstract This article has no abstract. More >

  • Open Access

    ARTICLE

    Regulation of Cyclic Longitudinal Mechanical Stretch on Proliferation of Human Bone Marrow Mesenchymal Stem Cells

    Guanbin Song∗,†,‡, Yang Ju∗,†,§, Hitoshi Soyama*, Toshiro Ohashi, Masaaki Sato

    Molecular & Cellular Biomechanics, Vol.4, No.4, pp. 201-210, 2007, DOI:10.3970/mcb.2007.004.201

    Abstract Mechanical stimulation is critical to both physiological and pathological states of living cells. Although a great deal of research has been done on biological and biochemical regulation of the behavior of bone marrow mesenchymal stem cells (MSCs), the influence of biomechanical factors on their behavior is still not fully documented. In this study, we investigated the modulation of mechanical stretch magnitude, frequency, and duration on the human marrow mesenchymal stem cells (hMSCs) proliferation by an in vitro model system using a mechanical stretch loading apparatus, and optimized the stretch regime for the proliferation of hMSCs.… More >

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