961 research outputs found

    VEGF, VEGFR-1 and VEGFR-2 immunoreactivity in the porcine arteries of vascular subovarian plexus (VSP) during the estrous cycle.

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    Abstract: Vascular endothelial growth factor (VEGF) is an important angiogenic factor in the female reproductive tract. It binds to cell surface through ligand-stimulatable tyrosine kinase receptors, the most important being VEGFR-1 (flt-1) and VEGFR-2 (flk-1). The broad ligament of the uterus is a dynamic organ consisting of specialized complexes of blood vessels connected functionally to the uterus, oviduct and ovary. Endothelial cells form an inner coating of the vessel walls and thus they stay under the influence of various modulators circulating in blood including ovarian steriods involved in developmental changes in the female reproductive system. The aim of the present study was to immunolocalize VEGF and its two receptors: VEGFR-1 and VEGFR-2 in the broad ligament of the uterus in the area of vascular subovarian plexus during different phases of the estrous cycle in pig and to determine the correlation between immunoreactivity of the investigated factors and phases of the estrous cycle. The study was performed on cryostat sections of vascular subovarian plexus stained immunohistochemically by ABC method. Specific polyclonal antibodies: anti-VEGF, anti-VEGFR-1 and anti-VEGFR-2 were used. Data were subjected to one-way analysis of variance. Our study revealed the presence of VEGF and its receptors in endothelial and smooth muscle cells of VSP arteries. All agents displayed phase-related differences in immunoreactivity suggesting the modulatory effect of VEGF, VEGFR-1 and VEGFR-2 on the arteries of the VSP in the porcine broad ligament of the uterus

    A 1.5D model of a complex geometry laboratory scale fuidized bed clc equipment

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    The awareness of the climate changes has resulted in the development of new technologies allowing to increase the effectiveness and to lower the costs of CO2 separation from the flue gas. One of the most promised combustion technology of fossil fuels is Chemical Looping Combustion (CLC). The technology is considered to be one of the cheapest techniques for CO2 capture (1). Since it is still an emerging technology and the complexity of processes are still not sufficiently recognized, the development of a simple model of CLC equipment is of practical significance. The paper presents a 1.5D model of the laboratory-scale fluidized bed CLC equipment for Innovative Idea for Combustion of Solid Fuels via Chemical Looping Technology – NewLoop. The idea combines two technologies making them complementary: Chemical looping with Oxygen Uncoupling (CLOU) and In-situ Gasification Chemical Looping (iG-CLC). Experimental studies, calculations and model validation were performed for the CLC unit (Fig. 1). The unit constitutes two cycles: the main cycle and internal cycle with Air Reactor (AR) and Fuel Reactor (FR). Smooth glass microspheres with the Sauter mean diameter of particles of 141 µm and the density of 2450 kg/m3 were used during the investigation. Since the model is in the development stage the study was conducted for the cold tests at which the unit operated stably and smoothly. The model is performed by the use of Comprehensive Simulator of Fluidized and Moving Bed equipment (CeSFaMB). The CeSFaMB has its first successful version completed in 1987. Since then, various versions have been developed and validated for a wide range of cases (2). The first operational results with this CLC unit, i.e. fluidization dynamics are discussed, since the geometry of the system is rather complex. Pressure drops, void fractions, bubble diameter and rising velocity are determined. The results show good agreement between calculated and experimental parameters. On the matter of fluidization dynamics, CeSFaMB produces the parameters as function of vertical coordinate. As an example, the void fractions as well as bubble diameter and rising velocity in the dense region of the Air Reactor are illustrated in Fig 2. Please click Additional Files below to see the full abstract

    Combining frequency and time domain approaches to systems with multiple spike train input and output

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    A frequency domain approach and a time domain approach have been combined in an investigation of the behaviour of the primary and secondary endings of an isolated muscle spindle in response to the activity of two static fusimotor axons when the parent muscle is held at a fixed length and when it is subjected to random length changes. The frequency domain analysis has an associated error process which provides a measure of how well the input processes can be used to predict the output processes and is also used to specify how the interactions between the recorded processes contribute to this error. Without assuming stationarity of the input, the time domain approach uses a sequence of probability models of increasing complexity in which the number of input processes to the model is progressively increased. This feature of the time domain approach was used to identify a preferred direction of interaction between the processes underlying the generation of the activity of the primary and secondary endings. In the presence of fusimotor activity and dynamic length changes imposed on the muscle, it was shown that the activity of the primary and secondary endings carried different information about the effects of the inputs imposed on the muscle spindle. The results presented in this work emphasise that the analysis of the behaviour of complex systems benefits from a combination of frequency and time domain methods

    Molecular biology for the radiation oncologist: The 5rs of radiobiology meet the hallmarks of cancer

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    ABSTRACT: Recent advances in our understanding of the biology of cancer have provided enormous opportunities for the development of novel therapies against specific molecular targets. It is likely that most of these targeted therapies will have only modest single agent activities but may have the potential to accentuate the therapeutic effects of ionising radiation. In this introductory review, the 5Rs of classical radiobiology are interpreted in terms of their relationship to the hallmarks of cancer. Future articles will focus on the specific hallmarks of cancer and will highlight the opportunities that exist for designing new combination treatment regimens. Harrington, K. et al. (2007). Clinical Oncology 19, 561e57

    The response surface methodology for optimization of tyrosinase immobilization onto electrospun polycaprolactone-chitosan fibers for use in bisphenol A removal.

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    Composite polycaprolactone-chitosan material was produced by an electrospinning method and used as a support for immobilization of tyrosinase by mixed ionic interactions and hydrogen bonds formation. The morphology of the fibers and enzyme deposition were confirmed by SEM images. Further, multivariate polynomial regression was used to model the experimental data and to determine optimal conditions for immobilization process, which were found to be pH 7, temperature 25 °C and 16 h process duration. Under these conditions, novel type of biocatalytic system was produced with immobilization yield of 93% and expressed activity of 95%. Furthermore, as prepared system was applied in batch experiments related to biodegradation of bisphenol A under various remediation conditions. It was found that over 80% of the pollutant was removed after 120 min of the process, in the temperature range 15-45 °C and pH 6-9, using solutions at concentration up to 3 mg/L. Experimental data collected proved that the stability and reusability of the tyrosinase were significantly improved upon immobilization: the immobilized biomolecule retained around 90% of its initial activity after 30 days of storage, and was still capable to remove over 80% of bisphenol A even after 10 repeated uses. By contrast, free enzyme was able to remove over 80% of bisphenol A at pH 7-8 and temperature range 15-35 °C, and retained less than 60% of its initial activity after 30 days of storage

    Two-dimensional effects in laser-created plasmas measured with soft-x-ray laser interferometry

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    Includes bibliographical references (pages 056409-6).Soft-x-ray laser interferograms of laser-created plasmas generated at moderate irradiation intensities (1×1011-7×1012 W cm-2) with λ = 1.06 μm light pulses of ~13-ns-FWHM (full width at half maximum) duration and narrow focus (~30 μm) reveal the unexpected formation of an inverted density profile with a density minimum on axis and distinct plasma sidelobes. Model simulations show that this strong two dimensional hydrodynamic behavior is essentially a universal phenomena that is the result of plasma radiation induced mass ablation and cooling in the areas surrounding the focal spot
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