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Wyszukujesz frazę "Hamed, A. I." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Effect of the proanthocyanidin fraction from Medemia argun on the in vitro growth and activity of selected soil microorganisms
Autorzy:
Martyniuk, S.
Hamed, A. I.
Gębala, B.
Stochmal, A.
Powiązania:
https://bibliotekanauki.pl/articles/960253.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Opis:
Many substances of plant origin, e.g. alkyloresorcinols, benzoxazinoids, essential oils, isothiocyanates or saponins, have been tested as potential antimicrobial agents to control various pathogenic microorganisms. Medemia agrun is a mysterious, not well-known species of the fan palm from the Nubian Desert Oases of Southern Egypt and Northern Sudan. Nuts of M. argun have been found to be rich (about 5%) in proanthocyanidins, consisting of afzelechin, catechin and gallocatechin as the main subunits of these polyphenolic compounds. The aim of this work was to assess effects of the proanthocyanidin (PAC) fraction obtained from M. agrun nuts on the in vitro growth and activity of two soil-borne fungal pathogens of cereals (Gaeumannomyces graminis var. tritici and Cephalosporium gramineum) and a beneficial soil bacterium, Azotobacter chroococcum, known to fix atmospheric nitrogen. The fungi were grown on PDA medium and A. chroococcum was cultured on Burk’s N-free medium supplemented with different concentrations of the PAC fraction. This fraction applied at the highest concentration tested (200 μg cm-3) did not affect the mycelial growth of the fungus Cephalosporium gramineum on PDA medium but significantly reduced (by 20%) that of Gaeumannomyces graminis var. tritici. Proliferation and N2-fixation by Azotobacter chroococcum in N-free liquid medium containing 500 μg cm-3 of the PAC fraction were more intensive than those in the medium with an equivalent concentration of glucose. It has been shown for the first time that this bacterium can use the PAC fraction as the only source of C and energy for N2-fixation.
Źródło:
Journal of Elementology; 2017, 22, 1
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
PCR-based detection of Helicobacter pylori and non-Helicobacter pylori species among humans and animals with potential for zoonotic infections
Autorzy:
Youssef, A.I.
Afifi, A.
Abbadi, S.
Hamed, A.
Enany, M.
Powiązania:
https://bibliotekanauki.pl/articles/2087111.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Helicobacter spp.
zoonotic infections
detection
identification
Źródło:
Polish Journal of Veterinary Sciences; 2021, 24, 3; 445-450
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A proposed preamble channel estimation scheme for flip FBMC-based indoor VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2063904.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
channel estimation
filter bank multicarrier
IEEE 802.15.7 standard
interference approximation method
visible light communication
Opis:
Filter bank multicarrier waveform is investigated as a potential waveform for visible light communication broadcasting systems. Imaginary inter-carrier and/or inter-symbol interference are causing substantial performance degradation in the filter bank multicarrier system. Direct current-biased optical filter bank multicarrier modulation overcomes all the problems of direct current-biased optical-orthogonal frequency division multiplexing modulation approaches in terms of speed and bandwidth. However, it also wastes a lot of energy while transforming a true bipolar signal into a positive unipolar signal by adding direct current-bias. In this paper, a flip-filter bank multicarrier-based visible light communication system was introduced to overcome this problem. In this system, a bipolar signal is converted to a unipolar signal by isolating the positive and negative parts, turning them to positive and then delivering the signal. Also, a new channel estimation scheme for a flip-filter bank multicarrier system is proposed which improves the channel estimation performance compared to that of each of the conventional schemes. The proposed system performance is measured in terms of bit error rate, normalized mean squared error, and constellation diagram. The superiority of the proposed scheme over other conventional structures has been successfully verified by MATLAB 2020b simulation experiments results. These results are evaluated under indoor visible light communication standard.
Źródło:
Opto-Electronics Review; 2022, 30, 1; art. no. e140859
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid PAPR reduction schemes for different OFDM-based VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174839.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
peak-to-average power ratio
bit error rate
Opis:
Orthogonal frequency division multiplexing has been widely used in many radio frequency wireless communication standards as a preferable multicarrier modulation scheme. The modulated signals of a conventional orthogonal frequency division multiplexing system are complex and bipolar. In intensity-modulated direct detection optical wireless communications, transmitted signals should be real and unipolar due to non-coherent emissions of an optical light emitting diode. In this paper, different hybrid optical systems have been proposed to satisfy real and unipolar signals. Peak-to-average power ratio is one of the biggest challenges for orthogonal frequency division multiplexing-based visible light communications. They are based on a combination of non-linear companding techniques with spreading or precoding techniques. Simulation evaluation is performed under direct current-biased optical orthogonal frequency division multiplexing, asymmetrically clipped optical orthogonal frequency division multiplexing, and Flip-orthogonal frequency division multiplexing systems in terms of peak-to-average power ratio, bit error rate, and spectral efficiency. The proposed schemes are investigated to determine a scheme with a low peak-to-average power ratio and an acceptable bit error rate. MATLABTM software has been successfully used to show the validity of the proposed schemes.
Źródło:
Opto-Electronics Review; 2022, 30, 3; art. no. e141951
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid PAPR reduction schemes for different OFDM-based VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174840.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
peak-to-average power ratio
bit error rate
Opis:
Orthogonal frequency division multiplexing has been widely used in many radio frequency wireless communication standards as a preferable multicarrier modulation scheme. The modulated signals of a conventional orthogonal frequency division multiplexing system are complex and bipolar. In intensity-modulated direct detection optical wireless communications, transmitted signals should be real and unipolar due to non-coherent emissions of an optical light emitting diode. In this paper, different hybrid optical systems have been proposed to satisfy real and unipolar signals. Peak-to-average power ratio is one of the biggest challenges for orthogonal frequency division multiplexing-based visible light communications. They are based on a combination of non-linear companding techniques with spreading or precoding techniques. Simulation evaluation is performed under direct current-biased optical orthogonal frequency division multiplexing, asymmetrically clipped optical orthogonal frequency division multiplexing, and Flip-orthogonal frequency division multiplexing systems in terms of peak-to-average power ratio, bit error rate, and spectral efficiency. The proposed schemes are investigated to determine a scheme with a low peak-to-average power ratio and an acceptable bit error rate. MATLABTM software has been successfully used to show the validity of the proposed schemes.
Źródło:
Opto-Electronics Review; 2022, 30, 3; art. no. e141951
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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