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  • Open Access

    ARTICLE

    Isolation of epithelial cells, villi and crypts from small intestine of pigeons (Columba livia)

    OSCAR MAC DONAL1, JUAN G. CHEDIACK1,2,3, ENRIQUE CAVIEDES-VIDAL1,2,3

    BIOCELL, Vol.32, No.3, pp. 219-227, 2008, DOI:10.32604/biocell.2008.32.219

    Abstract The isolation of viable enterocytes, villi and crypts from the small intestine of a feral bird (Columba livia) is important for performing physiological experiments in ecologically relevant processes of membrane transport. The effectiveness of mechanical disruption, enzymatic digestion and chelating agents were compared. The objectives were to isolate enterocytes, villi and crypts from the small intestine of young pigeons; to evaluate the viability of the isolated intestinal epithelial cells isolated; and to verify the integrity of enterocytes by biochemical features. Enzymatic and mechanical methods yielded both elongated columnar and spherical cells. With the chelating method villi More >

  • Open Access

    ARTICLE

    Brief Communication : Spherites in the midgut epithelial cells of the sugarcane borer parasitized by Cotesia flavipes

    DANIELA DE OLIVEIRA PINHEIRO*, HÉLIO CONTE**, ELISA APARECIDA GREGÓRIO*

    BIOCELL, Vol.32, No.1, pp. 61-67, 2008, DOI:10.32604/biocell.2008.32.061

    Abstract Diatraea saccharalis, the main pest of sugarcane, has been controlled by Cotesia flavipes. Very little is known about the effect of parasitism on the host organs, including the midgut. The Lepidoptera midgut epithelium is composed of columnar, goblet, regenerative, and endocrine cells. Spherites have been described in columnar and regenerative cells of several Lepidoptera species, and presented a lot of functional meaning. We identified spherites in the midgut epithelial cells of non-parasitized D. saccharalis larvae analyzed the effect of parasitism on spherite morphology and distribution along the length of the midgut. Midgut fragments of both non-parasitized and parasitized… More >

  • Open Access

    ARTICLE

    A cryopreservation protocol for immature zygotic embryos of species of Ilex (Aquifoliaceae)

    LUIS A. MROGINSKI*, PEDRO A. SANSBERRO, ADRIANA M. SCOCCHI, CLAUDIA LUNA, HEBE Y. REY

    BIOCELL, Vol.32, No.1, pp. 33-39, 2008, DOI:10.32604/biocell.2008.32.033

    Abstract Tropical Ilex species have recalcitrant seeds. This work describes experiments demonstrating the feasibility of long-term conservation of Ilex brasiliensis, I. brevicuspis, I. dumosa, I. intergerrima, I. paraguariensis, I. pseudoboxus, I. taubertiana, and I. theezans through cryopreservation of zygotic rudimentary embryos at the heart developmental stage. The embryos were aseptically removed from the seeds and precultured (7 days) in the dark, at 27± 2ºC on solidified (0.8% agar) 1/4MS medium, [consisting of quarterstrength salts and vitamins of Murashige and Skoog (1962) medium] with 3% sucrose and 0.1 mg/l Zeatin. The embryos were then encapsulated in 3% calcium alginate beads… More >

  • Open Access

    ARTICLE

    Use of the pressure chamber and thermocouple psychrometers to determine the water relations of plant tissues

    Busso CA

    Phyton-International Journal of Experimental Botany, Vol.77, pp. 327-350, 2008, DOI:10.32604/phyton.2008.77.327

    Abstract Advantages, disadvantages and precautions of using the pressure chamber and thermocouple psychrometers for determinations of plant water potential, and osmotic and turgor pressures are discussed. Comparison of results obtained with both instruments will be influenced by the sampling technique, consistency in both sampling and measurement procedures, and errors inherent to the method itself. In-situ readings of either plant or soil water potential with thermocouple psychrometers are perhaps worthless, or worse (they may even be misleading). Use of thermocouple psychrometers is strictly limited to the laboratory where isothermal conditions can be obtained. The method to determine the More >

  • Open Access

    ARTICLE

    Experimental Assessment of Stress Intensity Factors in Internal Cracks under Mixed-mode Loading

    C. Colombo1, M. Guagliano1,2, L. Vergani1

    Structural Durability & Health Monitoring, Vol.4, No.2, pp. 67-76, 2008, DOI:10.3970/sdhm.2008.004.067

    Abstract With the aim of experimentally assessing the stress intensity factors under mixed-mode loading along a crack front, the case of an internal elliptical crack is analyzed. An experimental test is performed on a three-dimensional photoelastic model made in epoxy resin. This model contains an inner natural crack, created by thermal shock. The crack is inclined in the cylindrical model, loaded with a tensile stress field.
    Exploiting the characteristics of the epoxy resin, and using the stress freezing technique, it is possible to keep memory of the stresses near to the crack tip, once the specimen is unloaded. More >

  • Open Access

    ARTICLE

    Modeling of a Surface Contact Stress for Spur Gear Mechanism using Static and Transient Finite Element Method

    F. R. M. Romlay1

    Structural Durability & Health Monitoring, Vol.4, No.1, pp. 19-28, 2008, DOI:10.3970/sdhm.2008.004.019

    Abstract This paper presents a surface contact static stress of a spur gear system combined with dynamic characteristic using transient Finite Element Method (FEM). Traditionally, the static stress analysis is done separately with dynamic properties due to limitation of complex equation and avoiding of error occurred. However, in this paper, static stress information is combined with the dynamic mechanism due to the time consuming during the design and analysis stage. A transient FEM analysis is carried out to formulate and solve large systems of algebraic equations in order to obtain a relationship between the contact parameter… More >

  • Open Access

    ABSTRACT

    An Improved Tracking Technique for Assessment of High Resolution Dynamic Radiography Kinematics

    G. Papaioannou1, C. Mitrogiannis1, G. Nianios1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.2, pp. 41-46, 2008, DOI:10.3970/icces.2008.008.041

    Abstract Previous attempts to track skeletal kinematics from sequences of images acquired using biplane dynamic radiography report challenges in automating the tracking technique due to image resolution issues, occlusion from segments appearing synchronously in the field of view and computational load. This translates into many hours of manual work to export the kinematics. The proposed new tracking method tackles the above problems and reduces the time to export kinematics from several hours to less than 3 minutes. More >

  • Open Access

    ABSTRACT

    An Experimental Method for Kinematic Measurement of a Four-Bar Mechanism by Digital Video Analysis

    Romy P. Moreno1, Mario G. Villeda2, Sergio A. V. Pruneda2, Zeferino D. Noriega2, Pedro G. Segura2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.8, No.1, pp. 19-24, 2008, DOI:10.3970/icces.2008.008.019

    Abstract Measuring the position, speed and acceleration of the moving elements of a mechanism usually involves external instrumentation that has to be attached to it, which is not always feasible. The method discussed here provides an alternative to measure these kinematics characteristics without modifying the components. To test the method in a controlled environment a four-bar mechanism was build. It was designed to be as thin as possible and to allow arbitrary changes in its lengths. Three commercial programs and a specially designed software (KIMA{\textregistered }) are used to record, analyze, measure, compute and verify the More >

  • Open Access

    ABSTRACT

    The Descending Aortic Aneurysm under Vascular Structure having Three-layered using FSI

    O. Ohta1, F. Gao1, T. Matsuzawa2

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.3, pp. 146-150, 2008, DOI:10.3970/icces.2008.007.146

    Abstract The aortic disease is 2nd place of the cause of death. If the thoracic part and the dissociation are matched, the aortic aneurysm exceeds 60 percent. The aneurysm decided based on the maximum diameter of the aneurysm from the image of which it takes a picture with CT or MRI etc. as such a diagnostic indicator. The appearance of disease, the development, and the rupture of the arterial hemangioma are thought that the hemodynamics such as intravasculars and vessel walls plays an important role [1,2]. Then, we simulated the aneurysm of descending aorta in consideration More >

  • Open Access

    ABSTRACT

    FE-Simulation of Nonlinear Vibration and Stability Control of Smart Structures

    S. Lentzen1, R. Schmidt1

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 201-206, 2008, DOI:10.3970/icces.2008.006.201

    Abstract In the present work the significance of considering geometrical nonlinearity in the application of piezoelectric materials in order to improve the dynamic and stability characteristics of thin structures is shown. For the numerical investigations a finite shell element has been used which employs strain displacement relations based on the first-order shear deformation moderate rotation theory. An ANS formulation has been used to overcome membrane and shear locking. Two numerical examples are shown. The first example deals with increasing the critical buckling load by incorporating piezoelectric layers into the structure. In the second example the nonlinear More >

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