51 research outputs found

    Analysis of an axially loaded composite tube measured by distributed fiber optic sensors

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    Financial support was provided for this study by the Grant Agency of the Czech Technical University in Prague; grant no. SGS21/151/OHK2/3T/12, and by the Technology Agency of the Czech Republic, grant no. TJ02000252, FW01010450This work shows an axially loaded composite tube that represents a rod body with a wrapped joint. For the experimental analysis, distributed fiber optic sensors installed on the surface of the rod were used to analyse axial, and radial deformations and local changes in the joint region under tensile loading until failure

    Electron-Impact Excitation to the 4p⁵5s and 4p⁵5p Levels of Kr | Using Different Distorted-Wave and Close-Coupling Methods

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    Electron-impact excitation of the 4p55s and 4p55p levels of Kr I has been investigated in detail by calculating cross sections using distorted-wave and close-coupling approaches. The results are presented from the excitation thresholds up to 50 eV incident energy. They are contrasted among the different calculations and compared with other theoretical predictions and experimental data. Significant disagreement is found with many of the recent experimental data of Chilton et al. [Phys. Rev. A 62, 032714 (2000)]

    Electron-Impact Excitation from the (4p⁵5s) Metastable States of Krypton

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    Theoretical results from multistate semirelativistic Breit-Pauli R-matrix calculations and two first-order distorted-wave calculations are presented for electron-impact excitation of krypton from the (4p55s) J = 0,2 metastable states to the (4p55s) and (4p55p) manifolds. Except for a few cases, in which the method to account for relativistic effects becomes surprisingly critical, fair overall agreement between the predictions from the various theoretical models is achieved for intermediate and high energies. However, significant discrepancies remain with the few available experimental data

    Signaling pathways and genes regulating oocyte maturation in pig

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    The gonadotropin-induced resumption of meiosis and cumulus expansion in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like factors, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. In vitro, the EGF-like peptides are also produced in cumulus cells upon stimulation by FSH. Both FSH and the EGF-like peptides stimulate resumption of meiosis and cumulus expansion in vitro via activation of a broad signaling network in cumulus cells. To define signaling pathways that drive FSH- and AREG-induced cumulus expansion and meiotic resumption, in vitro cultured pig cumulus-oocyte complexes (COCs) were treated with specific protein kinase inhibitors. The results document that FSH-stimulated, but not the AREG-stimulated resumption of meiosis, depends on the PKA and MAPK14 activities; both modes of stimulation require activation of EGFR and MAPK3/1. To characterize the effects of FSH and EGF-like peptides on gene expression in cumulus cells, transcriptomes of cumulus cells were analysed using microarray approach. Both FSH and AREG+EREG increased the expression of genes associated with regulation of cell proliferation, blood coagulation and extracellular matrix remodeling. In contrast to AREG+EREG, FSH also increased the expression of genes coding..

    Methods of molecular and cell biology in the frame of secondary school education

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    Teaching of cell and molecular biology is often restricted by financial and material limitations as well as a lack of expertise. These problems may be overcome by cooperation with scientific institutions and universities. Some scientists teach select courses under the auspices of high school. Others allow students to fulfill internships at their workplaces. The first aim of this thesis is to describe the characteristics of summer school, wherein the participants are integral for providing feedback on what matters most to them. The second goal of the study is to perform four molecular biology lab lessons in the advanced placement genetics course. The results of a qualitative research conducted among summer school participants have shown the benefits present due to contact that occurs between people of the same genuine interest. Student evaluation of molecular biology lessons performed in the advanced placement course revealed that the lab lessons are feasible and positively accepted by students. The thesis also highlights the importance of cooperation between high school and academia. Key words: molecular biology, DNA, secondary schools, gifted student

    The Effect of EGF - like Peptides on Cumulus-Oocyte Complexes

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    In mammals, the ovarian cycle is controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH), secreted by the anterior lobe of the pituitary gland. FSH is assumed to be essential for follicle growth. LH is required for the terminal phases of follicle growth, estrogen synthesis, ovulation, development of the corpus luteum and progesterone synthesis. Although cumulus cells and oocytes lack LH-receptors, LH causes cumulus expansion and meiosis resumption. The effect of LH is mediated via EGF-like peptides - amphiregulin (AREG), epiregulin (EREG) and betacellulin (BTC). The precursors of these peptides are present in the mural granulosa cells and EGF-like peptides are released by activation of metalloproteases in response to LH-stimulus. The aim of this thesis is to present EGF-like peptides in the wide context of the molecular mechanisms regulating the late phases of folliculogenesis and meiotic maturation of oocytes

    The Effect of EGF - like Peptides on Cumulus-Oocyte Complexes

    No full text
    In mammals, the ovarian cycle is controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH), secreted by the anterior lobe of the pituitary gland. FSH is assumed to be essential for follicle growth. LH is required for the terminal phases of follicle growth, estrogen synthesis, ovulation, development of the corpus luteum and progesterone synthesis. Although cumulus cells and oocytes lack LH-receptors, LH causes cumulus expansion and meiosis resumption. The effect of LH is mediated via EGF-like peptides - amphiregulin (AREG), epiregulin (EREG) and betacellulin (BTC). The precursors of these peptides are present in the mural granulosa cells and EGF-like peptides are released by activation of metalloproteases in response to LH-stimulus. The aim of this thesis is to present EGF-like peptides in the wide context of the molecular mechanisms regulating the late phases of folliculogenesis and meiotic maturation of oocytes

    Methods of molecular and cell biology in the frame of secondary school education

    No full text
    Teaching of cell and molecular biology is often restricted by financial and material limitations as well as a lack of expertise. These problems may be overcome by cooperation with scientific institutions and universities. Some scientists teach select courses under the auspices of high school. Others allow students to fulfill internships at their workplaces. The first aim of this thesis is to describe the characteristics of summer school, wherein the participants are integral for providing feedback on what matters most to them. The second goal of the study is to perform four molecular biology lab lessons in the advanced placement genetics course. The results of a qualitative research conducted among summer school participants have shown the benefits present due to contact that occurs between people of the same genuine interest. Student evaluation of molecular biology lessons performed in the advanced placement course revealed that the lab lessons are feasible and positively accepted by students. The thesis also highlights the importance of cooperation between high school and academia. Key words: molecular biology, DNA, secondary schools, gifted student
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