Browsing by Author "Ibrahim M."

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    Overview of MDM2 and B-RAF expression in gastric lesions
    (Springer, 2018) Aboushousha T.; Helal N.; Hammam O.; Ibrahim M.; Khaled S.; Mostafa A.; Anas A.; Department of Pathology; Theodor Bilharz Research Institute; Imbaba; Giza; Egypt; Faculty of Biotechnology; October University of Modern Sciences and Arts; Giza; Egypt; Department of Surgery; Theodor Bilharz Research Institute; Imbaba; Giza; Egypt; Department of Hepato-Gastroenterology; Theodor Bilharz Research Institute; Giza; Egypt
    BACKGROUND: Globally, gastric cancer (GC) it is the fourth most common cancer and the third cause of cancer-related deaths. Overexpression of MDM2 and B-RAF appeared to be increased in malignancy and associated with poor prognosis in several human tumours, but their role in gastric cancer remains controversial. AIM: We had investigated the immunohistochemical expression of MDM2 and B-RAF in 136 gastric lesions with/without H. pylori association. MATERIAL AND METHODS: Studied specimens include chronic gastritis (32), intestinal type GC (70), diffuse GC (22) and gastrointestinal stromal tumours (GIST) (12). RESULTS: MDM2 expression increased significantly in intestinal GC compared to other groups (p < 0.001), while B-RAF expression increased significantly in GIST compared to other groups (p < 0.001). H. pylori increased expression of MDM2 in intestinal GC cases but did not affect B-RAF expression. MDM2 expression correlated with high grade of tumor differentiation (p < 0.001), deep invasion (p < 0.05), nodal metastases (p < 0.05) and distant metastases (p < 0.1) in intestinal GC, while B-RAF expression did not correlate with TNM stage (p < 0.1). CONCLUSION: MDM2 up-regulation was more frequent in intestinal GC, while B-RAF up-regulation was more frequent in GIST compared to other groups; MDM2 expression in intestinal GC was correlated with H. pylori association, high grade of differentiation, deep invasion, nodal and distant metastases, meanwhile, B-RAF expression was correlated with high-grade intestinal GC but did not correlate with H. pylori or TNM stage. The possible role of both MDM2 and B-RAF in predicting progression of gastric tumours and prognosis deserves further investigations. 2018 Tarek Aboushousha, Noha Helal, Olfat Hammam, Manar Ibrahim, Samar Khaled, Amr Mostafa, Amgad Anas.
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    Performance investigation of wimax 802.16m in mobile high altitude platforms
    (Asian Research Publishing Network (ARPN), 2013) Ibrahim M.; Zahara M.M.; Noaman S.; Ragab A.S.; Department of communications; TELECOM EGYPT; MSA UNIVESITY; Egypt; Department of Communications Engineering; AL AZHAR UNIVESITY; Egypt
    Providing WiMax broadband services via high altitude platforms (HAPs) is still an open research issue. One of the major problems affecting the system performance on the link level is Doppler Effect caused by the mobility of the served users. This paper investigates the Doppler effects on the bit error rate of mobile users in the downlink of the WiMax802.16m standard. The system key parameters that affect the error bit rate performance are also studied. These parameters include the channel propagation model. The Bit Error Probability (BEP) is the performance metric used to evaluate the downlink performance. Numerical results provided through simulations show that providing WiMax through high altitude platforms enhances the BER performance over that expected from conventional terrestrial systems. � 2005-2013 JATIT& LLS. All rights reserved.