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Search Results: 1 - 10 of 468955 matches for " Mohamed A. Yassin "
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Effect of the Cation Size Disorder at the A-Site on the Structural Properties of SrAFeTiO6 Double Perovskites (A = La, Pr or Nd)  [PDF]
Abdelrahman A. Elbadawi, O. A. Yassin, Mohamed A. Siddig
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.35003
Abstract: In this paper, the cation size disorder effect of the A-site on the structural properties of the SrAFe- TiO6 (A = La, Pr or Nd) was investigated. The compounds were synthesized—as the best of our knowledge—for the first time by conventional and precursor method to get crystalline materials. The results obtained from the experimental measurements carried out on new double perovskite materials were presented. The data of X-ray diffraction (XRD), Fourier Transform Infra Red FTIR were measured at room temperature. From the X-ray diffraction, and by means of standard Rietiveld method, all the samples have the same structure (orthorhombic) with Pnma space group. The difference in the tolerance factor is clearly noticed and refers to the cation size disorder at the A-sites. The Fourier Transform Infra Red FTIR measurement has been done; the results of it confirm the double perovskite structure and the difference between the samples were noticed. The tolerance factors for the samples altered from SrLaFeTiO6 up to SrNdFeTiO6 and this difference return to ionic radius and cation size effect.
Surface Modification of Waste Tire by Grafting with Styrene and Maleic Anhydride  [PDF]
Yassin A. Aggour, Ayed S. Al-Shihri, Mohamed R. Bazzt
Open Journal of Polymer Chemistry (OJPChem) , 2012, DOI: 10.4236/ojpchem.2012.22009
Abstract: Waste tire powder, as waste rubber WR was subjected to grafting with styrene (St) and maleic anhydride (MA). Hydrogen peroxide H2O2 was used to initiate the free radical copolymerization of St onto WR. A thermal initiation was used in case of grafting of MA onto WR. Effect of initiator and monomer concentrations together with the influence of reaction temperature and reaction time were investigated. The grafting was estimated by weight, and the grafted copolymers were characterized by FT/IR, DSC and SEM to prove the grafting. It has found that the grafting increases with increase monomer and initiator concentrations. The increase in the reaction temperature and time also causes increasing levels of the grafted St and MA.
Chemical Modification of Scraped Tires through Grafting with 2-Acrylamido-2-methylpropansulfonic Acid  [PDF]
Yassin A. Aggour, Ayied S. Al-Shihri, Mohamed R. Bazzet
Open Journal of Polymer Chemistry (OJPChem) , 2013, DOI: 10.4236/ojpchem.2013.33010
Abstract:

Scrap vulcanized rubber is amongst a bigger waste polymers. It does not decompose easily owing to its cross linked structure. Modification of scrap tires powder by the grafting with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) is described. The grafting is achieved through free radical initiation. The effects of different amount of monomer and initiator were examined. Also the influence of reaction time and temperature were investigated. The grafted waste rubber was characterized by FT/IR, SEM and DSC measurements. The proposed mechanism of the grafting reaction is discussed. From DSC and SEM studies of WR-g-AMPS compared with PAMPS and WR, the results show that the particle size and crystallinity were enhanced for the grafted copolymers. The obtained modified scraped tires will used as an ion exchanger for the future applications.

Pulmonary Hypertension Induced by Thalidomide (and Derivatives) in Patients with Multiple Myeloma: A Systematic Review  [PDF]
Abdulqadir J. Nashwan, Nader I. Al-Dewik, Hisham M. Al Sabah, Mohamed A. Yassin, Shehab F. Mohamed, Nabil H. Omar, Dana B. Mansour
Journal of Cancer Therapy (JCT) , 2016, DOI: 10.4236/jct.2016.713094
Abstract: Thalidomide is widely used in the treatment of multiple myeloma (MM). In recent years, several cases of pulmonary hypertension have been reported following treatment with thalidomide. The aim of this review was to evaluate the published literature on multiple myeloma patients with pulmonary hypertension following thalidomide treatment. A literature search was performed between 2000 and 2016. A total of 7 eligible studies were identified and deemed eligible, including 11 cases—approximately 37% (4 cases) with IgA (k), 27% (3 cases) with IgG (λ) MM, 27% (3 cases) with IgG (k) MM, and one case (9%) with primary plasma cell leukemia (PPCL). The vast majority of cases—82% (9 cases)—are associated with thalidomide, while only 18% (2 cases) are related to thalidomide derivatives (lenalidomide and pomalidomide). In conclusion, pulmonary hypertension induced by thalidomide or derivatives in multiple myeloma (MM) patients is related to a multifactorial etiology including the pathophysiology of the disease, thromboembolic events, preexisted cardiovascular conditions, comorbidities, and combination with other chemo- or bio-therapeutic agents. MM patients should be evaluated for signs and symptoms underlying cardiopulmonary disease before initiating, and during treatment with thalidomide.
Optical Code Division Multiple Access Performance Signature Over Multimode Optical Fiber Transmission Systems
Ahmed Nabih Zaki Rashed,Mohamed M. Zahra,Mohamed Yassin,Ismail A. Abd El-Aziz
International Journal of Advanced Research in Computer Science and Electronics Engineering , 2013,
Abstract: This paper has focused on the performance of an optical code division multiple access (OCDMA) system over multi mode optical fiber transmission systems and the transmission efficiency to be evaluated in order to determine the impact of multi access interference for a given number of users. It has recently attracted significant research interest because of the advantages it offers in terms of the flexibility in the management of the system resources. The optimum system design parameters are determined at a specific BER (bit error rate) with average repeater spacing and signal to noise ratio over multi mode fibers transmission systems for short, indoor and long applications.
Transmission Analysis of Optical Code Division Multiple Access Communication Systems in the Presence of Noise in Local Area Network Applications
Ahmed Nabih Zaki Rashed,Mohamed M. Zahra,Mohamed Yassin,Ismail A. Abd El- Aziz
International Journal of Basics and Applied Science , 2013,
Abstract: OCDMA is an essential part of the digital communication system now days for long haul, high speed networks. The biggest challenge with Optical CDMA system is to maintain the performance of the system and offer high bandwidth in case of higher number of users at minimum cost. As the number of users increase, the input requirements i.e. transmitted power, bit rate etc start increasing sharply which contribute to the additional cost. It has recently attracted significant research interest because of the advantages it offers in terms of the flexibility in the management of the system resources. We have taken into account the system design parameters are determined such as BER (bit error rate), signal to noise ratio (SNR), transmission bit rates, and optical received power for different code lengths. The Optical CDMA systems suffer from the problem of multiple access interference (MAI).As the number of users increase the BER error rate degrades because the effect of MAI (multiple access interference) increases. So, there is a limitation in number of users, as the number of users increase SNR decrease and probability of error increases.
Evaluation of Bilateral Mental Nerve Block as an Alternative to General Anesthesia for Resection of Lower Lip Tumors  [PDF]
Ashraf Khater, Islam A. Elzahaby, Mohamed Hamdy, Mohammad Zuhdy, Omar Hamdy, Mohamed Ezzat, Mahmoud Abdelaziz, Ahmad M. Farid, Mansour Elmoatasem, Amr Hassan, Khalid Atallah, Mahmoud Mostafa Saleh, Maha A. Abo-Zeid, Amr Yassin, Ola Taha Abd Eldayem, Mona Gad
Surgical Science (SS) , 2017, DOI: 10.4236/ss.2017.88035
Abstract: Objective: Nerve blockade is commonly used in oncosurgical procedures as an alternative to general anesthesia for older patients and those with significant medical problems. We report a single tertiary oncology center experience in performing various lip resections and reconstructive techniques using this technique. Patients and methods: sixty patients with lower lip tumors were enrolled into this study with exclusion of refusing, non-compliant and critically ill patients. A solution of 4 ml 2% Lidocaine and epinephrine was put in a 5 ml syringe. Half the solution (2 ml) was injected into each side with a 23 gauge needle and after 5 minutes the surgical resection was carried out after testing for anesthesia. Results: The mean age was 68 ± 6.2 years. The mean ASA score was 3 ± 0.75. There were 4 cases who expressed painful sensation and their operations were completed with fentanyl increments. Mean hospital stay was 1 ± 0.75 days. There were three cases of wound gaping who were treated with secondary closure in an outpatient basis. One patient expressed postoperative acute ischemic heart pain that was managed with anti-ischemic measurements. Conclusion: Bilateral mental nerve block is a safe and effective alternative to general anesthesia in lower lip tumors’ resection especially in older patients and those with poor tolerance for general anesthesia provided that there is no need for cervical nodal dissection.
Subclinical cerebrovascular cognitive function, and mood changes in patients with systemic lupus erythematosus
Ghaydaa A Shehata, Mohamed I Abdel-Kareem, Abd ellah N Yassin, et al
Open Access Rheumatology: Research and Reviews , 2010, DOI: http://dx.doi.org/10.2147/OARRR.S9711
Abstract: bclinical cerebrovascular cognitive function, and mood changes in patients with systemic lupus erythematosus Original Research (3542) Total Article Views Authors: Ghaydaa A Shehata, Mohamed I Abdel-Kareem, Abd ellah N Yassin, et al Published Date July 2010 Volume 2010:2 Pages 17 - 25 DOI: http://dx.doi.org/10.2147/OARRR.S9711 Ghaydaa A Shehata1, Mohamed I Abdel-Kareem2, Abd ellah N Yassin4, Abdel Ahamid R El Adl3 1Department of Neurology, Faculty of Medicine, Assiut University, Assiut, Egypt; 2Department of Rheumatology, Physical Medicine and Rehabilitation Faculty of Medicine, 3Department of Internal Medicine, Faculty of Medicine, Al-Azhar University, Assiut, Egypt; 4Department of Diagnostic Radiology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt Objective: To estimate the prevalence of neuropsychiatric disorders, cerebral atherosclerosis in patients with systemic lupus erythematosus (SLE) and explore the relation between transcranial duplex findings of different intracranial vessels with neuropsychiatric affect, and Systemic lupus erythematosus disease activity index (SLEDAI). Methods: Twenty-six consecutive SLE patients were evaluated for neurological and psychiatric disorders. Another 26 subjects matched with respect to age, sex, education, and socioeconomic status formed the control group. SLE disease activity was assessed by the SLEDAI. For each participant, a complete medical history was obtained and clinical, laboratory, and neurophysiological examinations, magnetic resonance imaging of the brain, transcranial duplex for intracranial vessels, and psychometric evaluations were performed. For the psychometric evaluation, we used the Modified Mini-mental State Examination and Cognitive Assessment Scale Inventory to assess cognitive function, and Hamilton Depression Rating Scale and Hamilton Anxiety Scale to assess symptoms of depression and anxiety. Results: Anxiety in 65.4% is the most prevalent manifestation followed by depression in 57.7%, headache in 38.5%, peripheral neuropathy in 26.9%, seizures in 23.1%, psychosis in 19.2%, radiculopathy and dementia in 15.4% for each, myositis in 11.5%, and stroke in 7.7%. There was a significant increased mean velocity and decreased pulsatility index of most studied intracranial vessels in both patient groups than in the control group. There was significant negative correlation between SLEDAI and transcranial Doppler findings in the pulsatility index of medial circumflex artery and procoagulant activity. Conclusion: Neurological disorders, cognitive impairment, depression, anxiety, psychosis and cerebrovascular changes detected by transcranial Doppler ultrasound are common in SLE.
Subclinical cerebrovascular cognitive function, and mood changes in patients with systemic  lupus erythematosus
Ghaydaa A Shehata,Mohamed I Abdel-Kareem,Abd ellah N Yassin,et al
Open Access Rheumatology: Research and Reviews , 2010,
Abstract: Ghaydaa A Shehata1, Mohamed I Abdel-Kareem2, Abd ellah N Yassin4, Abdel Ahamid R El Adl31Department of Neurology, Faculty of Medicine, Assiut University, Assiut, Egypt; 2Department of Rheumatology, Physical Medicine and Rehabilitation Faculty of Medicine, 3Department of Internal Medicine, Faculty of Medicine, Al-Azhar University, Assiut, Egypt; 4Department of Diagnostic Radiology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt Objective: To estimate the prevalence of neuropsychiatric disorders, cerebral atherosclerosis in patients with systemic lupus erythematosus (SLE) and explore the relation between transcranial duplex findings of different intracranial vessels with neuropsychiatric affect, and Systemic lupus erythematosus disease activity index (SLEDAI).Methods: Twenty-six consecutive SLE patients were evaluated for neurological and psychiatric disorders. Another 26 subjects matched with respect to age, sex, education, and socioeconomic status formed the control group. SLE disease activity was assessed by the SLEDAI. For each participant, a complete medical history was obtained and clinical, laboratory, and neurophysiological examinations, magnetic resonance imaging of the brain, transcranial duplex for intracranial vessels, and psychometric evaluations were performed. For the psychometric evaluation, we used the Modified Mini-mental State Examination and Cognitive Assessment Scale Inventory to assess cognitive function, and Hamilton Depression Rating Scale and Hamilton Anxiety Scale to assess symptoms of depression and anxiety.Results: Anxiety in 65.4% is the most prevalent manifestation followed by depression in 57.7%, headache in 38.5%, peripheral neuropathy in 26.9%, seizures in 23.1%, psychosis in 19.2%, radiculopathy and dementia in 15.4% for each, myositis in 11.5%, and stroke in 7.7%. There was a significant increased mean velocity and decreased pulsatility index of most studied intracranial vessels in both patient groups than in the control group. There was significant negative correlation between SLEDAI and transcranial Doppler findings in the pulsatility index of medial circumflex artery and procoagulant activity.Conclusion: Neurological disorders, cognitive impairment, depression, anxiety, psychosis and cerebrovascular changes detected by transcranial Doppler ultrasound are common in SLE.Keywords: SLE, SLEDAI, cognitive function, depression, anxiety, neurological disorders, TCD, cerebrovascular changes
Numerical Study of Flow and Gas Diffusion in the Near-Wake behind an Isolated Building

Mohamed F YASSIN,

大气科学进展 , 2009,
Abstract:
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