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Search Results: 1 - 10 of 9267 matches for " Elsayed Mohamed Deraz "
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Stochastic Analysis of Low-Cost Single-Frequency GPS Receivers  [PDF]
Mohamed Elsayed Elsobeiey
Positioning (POS) , 2016, DOI: 10.4236/pos.2016.73009
Abstract: Typically, dual-frequency geodetic grade GNSS receivers are utilized for positioning applications that require high accuracy. Single-frequency high grade receivers can be used to minimize the expenses of such dual-frequency receivers. However, user has to consider the resultant positioning accuracy. Since the evolution of low-cost single-frequency (LCSF) receivers is typically cheaper than single-frequency high grade receivers, it is possible to obtain comparable positioning accuracy if the corresponding observables are accurately modelled. In this paper, two LCSF GPS receivers are used to form short baseline. Raw GPS measurements are recorded for several consecutive days. The collected data are used to develop the stochastic model of GPS observables from such receivers. Different functions are tested to determine the best fitting model which is found to be 3 parameters exponential decay function. The new developed model is used to process different data sets and the results are compared against the traditional model. Both results from the newly developed and the traditional models are compared with the reference solution obtained from dual-frequency receiver. It is shown that the newly developed model improves the root-mean-square of the estimated horizontal coordinates by about 10% and improves the root-mean-square of the up component by about 39%.
Efficient Harmonic Analysis Technique for Prediction of IGS Real-Time Satellite Clock Corrections  [PDF]
Mohamed Elsayed Elsobeiey
Positioning (POS) , 2017, DOI: 10.4236/pos.2017.83003
Abstract: Real-time satellite orbit and clock corrections obtained from the broadcast ephemerides can be improved using IGS real-time service (RTS) products. Recent research showed that applying such corrections for broadcast ephemerides can significantly improve the RMS of the estimated coordinates. However, unintentional streaming interruption may happen for many reasons such as software or hardware failure. Streaming interruption, if happened, will cause sudden degradation of the obtained solution if only the broadcast ephemerides are used. A better solution can be obtained in real-time if the predicted part of the ultra-rapid products is used. In this paper, Harmonic analysis technique is used to predict the IGS RTS corrections using historical broadcasted data. It is shown that using the predicted clock corrections improves the RMS of the estimated coordinates by about 72%, 58%, and 72% in latitude, longitude, and height directions, respectively and reduces the 2D and 3D errors by about 80% compared with the predicted part of the IGS ultra-rapid clock corrections.
MMP-10/Stromelysin-2 Promotes Invasion of Head and Neck Cancer
Elsayed Mohamed Deraz, Yasusei Kudo, Maki Yoshida, Mariko Obayashi, Takaaki Tsunematsu, Hirotaka Tani, Samadarani B. S. M. Siriwardena, Mohammad Reza Kiekhaee, Guangying Qi, Shinji Iizuka, Ikuko Ogawa, Giuseppina Campisi, Lorenzo Lo Muzio, Yoshimitsu Abiko, Akira Kikuchi, Takashi Takata
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025438
Abstract: Background Periostin, IFN-induced transmembrane protein 1 (IFITM1) and Wingless-type MMTV integration site family, member 5B (Wnt-5b) were previously identified as the invasion promoted genes of head and neck squamous cell carcinoma (HNSCC) by comparing the gene expression profiles between parent and a highly invasive clone. We have previously reported that Periostin and IFITM1 promoted the invasion of HNSCC cells. Here we demonstrated that Wnt-5b overexpression promoted the invasion of HNSCC cells. Moreover, stromelysin-2 (matrix metalloproteinase-10; MMP-10) was identified as a common up-regulated gene among Periostin, IFITM1 and Wnt-5b overexpressing HNSCC cells by using microarray data sets. In this study, we investigated the roles of MMP-10 in the invasion of HNSCC. Methods and Findings We examined the expression of MMP-10 in HNSCC cases by immunohistochemistry. High expression of MMP-10 was frequently observed and was significantly correlated with the invasiveness and metastasis in HNSCC cases. Next, we examined the roles of MMP-10 in the invasion of HNSCC cells in vitro. Ectopic overexpression of MMP-10 promoted the invasion of HNSCC cells, and knockdown of MMP-10 suppressed the invasion of HNSCC cells. Moreover, MMP-10 knockdown suppressed Periostin and Wnt-5b-promoted invasion. Interestingly, MMP-10 overexpression induced the decreased p38 activity and MMP-10 knockdown induced the increased p38 activity. In addition, treatment with a p38 inhibitor SB203580 in HNSCC cells inhibited the invasion. Conclusions These results suggest that MMP-10 plays an important role in the invasion and metastasis of HNSCC, and that invasion driven by MMP-10 is partially associated with p38 MAPK inhibition. We suggest that MMP-10 can be used as a marker for prediction of metastasis in HNSCC.
Prevention of Nephropathy by Some Natural Sources of Antioxidants  [PDF]
Azab Elsayed Azab, Mohamed Omar Albasha, Ata Sedik Ibrahim Elsayed
Yangtze Medicine (YM) , 2017, DOI: 10.4236/ym.2017.14023
Abstract: Nephrotoxicity is one of the most common kidney problems and occurs when the body is exposed to a drug or toxin. Natural sources of antioxidants may serve as a vital source of potentially useful new compounds for the development of an effective therapy to combat a variety of kidney problems. Natural antioxidants have a variety of biochemical actions such as inhibition of reactive oxygen species production, scavenging of free radicals. The present review aims to summarize the recent articles which studied some of the nephrotoxic agents, and alleviation of nephrotoxicity using of some natural products possessing antioxidant properties. Our review shows the oxidative damage and renal disorders induced in human and experimental animals by nephrotoxic agents such as gentamicin, alcohol, nicotine, adenine, glycerol, ethylene glycol, sodium nitrite, mercuric chloride, AlCl3, lead acetate, carbon tetrachloride (CCl4), furosemide, carbendazim, diazinon, heat stress, and γ-radiation. Also, nephrotic disorders caused in diabetic rats, patients, cirrhotic ascetic patients, and ischemia-reperfusion. Administration of natural sources of antioxidants such as curcumin, garlic, fenugreek, parsley, peppermint, pomegranate, propolis, olive leaves, rosemary, and sesame attenuated both physiological and histopathological alterations induced in the kidney by the nephrotoxic agent and certain diseases. The nephroprotective effect of the former natural sources of antioxidants may be due to the enhancement of antioxidant activity and inhibition of tissue lipid peroxidation. It can be concluded that administration of curcumin, garlic, fenugreek, parsley, peppermint, pomegranate, propolis, olive leaves, rosemary, and sesame showed a remarkable kidney protection against nephrotoxic agents, and diseases induced renal dysfunctions in human and experimental animals. So, the present study recommended that the consumption of these natural sources of antioxidants may be useful for human exposure to nephrotoxic agents and patients who suffer from renal diseases.
Role of Reversed Sural Artery Flap in Reconstruction of Lower Third of the Leg, Ankle and Foot Defects  [PDF]
Mohamed Elsayed Mohamed Mohamed, Belal A. Al Mobarak
Modern Plastic Surgery (MPS) , 2018, DOI: 10.4236/mps.2018.83007
Abstract: Introduction: Coverage of defects of the distal lower extremity and foot remains a challenging reconstructive prcedure. Free tissue transfer remains the standard for the management of these defects. However, there are some disadvantages like; longer operative times, bulky contour, and the need for highly skilled expertise. The reverse superficial sural artery flap (RSSAF) is a distally based fasciocutaneous or adipo-fascial flap that is used for coverage of defects that involve the distal third of the leg, ankle, and foot. A significant advantage of this flap is a constant blood supply that does not require sacrifice of a major artery. Methods: Twenty RSSAF flaps were harvested for reconstruction of different traumatic soft tissue defects of the lower third of leg, ankle and foot. Follow up for 6 months postoperative. Results: Twenty Patients; twelve males and eight females underwent reconstruction of different soft tissue defects over the foot and ankle using RSSAF. The overall complications occurred in 6 flaps; 4 minor and 2 major complications. The remaining 14 flaps passed an uneventful follow up. Conclusions: The reverse superficial sural artery flap RSSAF can be used as a reliable alternative to free tissue transfer in reconstruction of defects over the lower third of leg, ankle, and foot. Venous congestion is the major threat to the flap but its incidence can be minimized by wide pedicle, less kink of the flap, and keep the venae comitants around the artery.
Acute Correction of Varus Knee by Biplanar Medial Opening-Wedge High Tibial Osteotomy and Fixation with TomoFix Plate  [PDF]
Elsayed Shaheen, Mohamed Abdel-Aal Morsy
Open Journal of Orthopedics (OJO) , 2019, DOI: 10.4236/ojo.2019.94009
Abstract: Background: Biplanar medial opening wedge high tibial osteotomy (MOWHTO) is a treatment method that allows adequate correction of symptomatic varus knee deformity. However, MOWHTO tends to decrease patellar height and increase the posterior tibial slope, which can affect the knee joint stability. Objective: The aim of this study was to describe the technique of biplanar MOWHTO and fixation by TomoFix plate, as well as to evaluate the accuracy of the planned correction and the postoperative tibial slope. Patients and Methods: This prospective cohort study was conducted on patients who presented with varus knee deformity and underwent biplanar MOWHTO and fixation by TomoFix plate during the period from March 2016 to March 2017. Assessment of patients included pre- and postoperative Knee and function scores, mechanical femorotibial angle (mFTA), posterior tibial slope angle (pTSA), range of motion (ROM) and radiological evaluation of the healing of the osteotomy site. Results: The recruited patients were 13 (8 men and 5 women), with average age 31.7 years old. The knee and functional scores improved from the preoperative mean of 45 and 41 to the postoperative mean of 85 and 72 points, respectively. The average knee flexion was 115 degrees, which at the final follow-up remained unchanged except for one case. The mean preoperative mFTA was 13.5° varus and decreased post-operatively to a mean of 3° valgus. The average postoperative follow-up period was 12 months (10 - 18 M). Conclusion: The biplanar MOWHTO allows preservation of posterior tibial slope while correcting the varus knee adequately.
A Comparative Study of Intrathecal Injection of Bupivacaine Alone or with Fentanyl, Clonidine, and Neostigmine in Lower Abdominal Surgeries  [PDF]
Elsayed Mohamed Abdelzaam, Ahmed Hamdy Abd Elrahman
Open Journal of Anesthesiology (OJAnes) , 2019, DOI: 10.4236/ojanes.2019.94009
Abstract: Background: Anesthesiologists are responsible for the development of pain services in the current era. Hence ideal adjuvants that can be used with bupivacaine for stable intraoperative conditions and prolonging the postoperative analgesia with fewer side effects are being investigated. Opioids, despite useful as adjuvants, are associated with undesirable side effects. Aim of the work: The study was done to compare analgesic efficacy and hemodynamic of intrathecal injection of bupivacaine alone or with fentanyl, clonidine, and neostigmine in lower abdominal surgeries, over the first 24 postoperative hours, in a randomized, double-blind, and clinical trial. Methods: 100 Patients were randomized into four equal groups, 25 patients in each group; Group B patients received 2.5 ml of 0.5% hyperbaric bupivacaine and 0.5 ml of normal saline. Group BF patients received 2.5 ml of 0.5% hyperbaric bupivacaine with (25 mics) of fentanyl. Group BC patients received 2.5 ml of 0.5% hyperbaric bupivacaine with 0.5 ml (75 mics) of clonidine. Group BN patients received 2.5 ml of 0.5% hyperbaric bupivacaine with 0.1 ml of neostigmine (50 mics) and 0.4 ml of normal saline. Intrathecal anesthesia was done with a recording of parameters intraoperative and the post-operative period. Each patient was assessed for hemodynamic parameters and effective analgesia in operation, and presence of complications (nausea, vomiting, sedation and pruritus) visual analogue pain score (VAS) postoperatively by a blinded investigator in the post-anesthesia care unit (PACU) and at 1, 2, 3, 4, 8 12, 18 and 24 h postoperatively. Results: The postoperative analgesia is more effective with group BC (the gold standard) than group B, group BF, and group BN. As regard complications during the study in all groups, complications as nausea, and vomiting were mainly with group BN; hypotension was primarily in group BC. Conclusion: Bupivacaine clonidine, bupivacaine neostigmine, and bupivacaine fentanyl intrathecal anesthesia produced a longer duration of postoperative analgesia after lower abdominal surgery in patients than bupivacaine alone. Bupivacaine clonidine mixture had the most extended period of analgesia, but with hypotension. So bupivacaine fentanyl mixture with moderate duration of analgesia and minimal side effects is most safe for a patient.
Simulation of Dual-Band MWCNT Ink-Based Spiral Antenna: A Comparative Study  [PDF]
Taha Elsayed Taha, Mohamed Ali Soliman, Ali Mohamed Gomaa, Wael Elsayed Swelam
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.44024
Abstract: In this paper, we compare a dual-band, square spiral microstrip patch antenna constructed from Multi-Walled Carbon Nanotubes (MWCNT) ink for wearable application simulated by Computer Simulation Technology Microwave Studio (CST MWS) by our work simulated by Advanced Design System (ADS) electromagnetic simulator using the same material characterization. The reflection coefficient is –12 dB at 1.2276 GHz for MWCNT and –13 dB at 1.25 GHz for the copper simulated by CST MWS and reflection coefficient is –12.235 dB at 1.234 GHz for MWCNT and –18.36 dB at 1.243 GHz for the copper simulated by ADS and the reflection coefficient is –27dB at 2.47 GHz for MWCNT and –13 dB at 2.53 GHz for the copper simulated by CST MWS and the reflection coefficient is –26.08 dB at 2.48 GHz for MWCNT and –17.031 dB at 2.47 GHz for the copper simulated by ADS. We show the meandering of the surface current on the radiating in spiral patch. The antenna gain is found to be –12.5 dBi at 1.22 GHz for MWCNT and is found –12.05 dBi at 1.25 GHz at CST MWS and the antenna gain is found to be –11.85 dBi at 1.235 GHz for MWCNT and is found –12.25 dBi at 1.243 GHz at ADS and the antenna gain is found to be –4.25 dBi at 2.47 GHz for MWCNT and is found –4.01 dBi at 2.53 GHz at CST MWS and the antenna gain is found to be –4.23 dBi at 2.47 GHz for MWCNT and is found –4.88 dBi at 2.45 GHz at ADS. We show a close agreement in the results obtained by the two simulation software's CST MWS and ADS. The results are given for both MWCNT and Copper characterizations.
Comparing the Efficacy of Dexmedetomidine When Used as an Adjuvant to Bupivacaine in Supraclavicular Brachial Plexus Blocks under Ultrasound-Guided  [PDF]
Elsayed Mohamed Abdelzaam
Open Journal of Anesthesiology (OJAnes) , 2019, DOI: 10.4236/ojanes.2019.95010
Abstract: Background: Ultrasound-guided for regional anesthesia offers many potential benefits in the emergency setting. Analgesia can be explicitly targeted to the region of pain and provide relief for many hours and decrease needing to the large volume of local anesthetic. The aim of the work: Comparing the efficacy of dexmedetomidine when used as an adjuvant to bupivacaine in supraclavicular brachial plexus blocks on the onset of sensory, motor blockade and postoperative analgesia. Patients and methods: This prospective, randomized, single-blind clinical study conducted on 60 patients underwent upper limb surgery done by ultrasound-guided supraclavicular brachial plexus block; these patients allocated into two equal groups: Group I (control) received 20 ccs (19 cc bupivacaine 0.5% + 1 cc saline), Group II received 20 cc (19 cc bupivacaine 0.5% + 1 cc volume of Dexmedetomidine 1 ug/kg). Results: Demographic data and surgical characteristics were comparable in both groups. The onset times for sensory and motor blocks were significantly shorter in Group II than Group I (P < 0.001), while the duration of blocks was considerably longer (P < 0.001) in Group II. Except for the first recordings (at 0, 5, and 10 min), heart rate levels in Group II were significantly lower (P < 0.001). MBP levels in Group II at 15, 30, 45, 60, 90 and 120 min were significantly lower than in Group I (P < 0.001). The duration of analgesia (DOA) was significantly longer in Group II than Group I (P < 0.001). As regards to the visual Analouge score, there is a highly significant difference at 6 hours, 8 hours and 10 hours in Group II than Group I. Conclusion: We recommend adding Dexmedetomidine to local anesthetics in peripheral nerve blocks to take advantage of the prolonged time of both sensory and motor blocks and prolonged postoperative analgesia.
A Novel Parallel Algorithm for Clustering Documents Based on the Hierarchical Agglomerative Approach
Amal Elsayed Aboutabl,Mohamed Nour Elsayed
International Journal of Computer Science & Information Technology , 2011,
Abstract: As the amount of internet documents has been growing, document clustering has become practicallyimportant. This has led the interest in developing document clustering algorithms. Exploiting parallelismplays an important role in achieving fast and high quality clustering. In this paper, we propose a parallelalgorithm that adopts a hierarchical document clustering approach. Our focus is to exploit the sources ofparallelism to improve performance and decrease clustering time. The proposed parallel algorithm istested using a test-bed collection of 749 documents from CACM. A multiprocessor system based onmessage-passing is used. Various parameters are considered for evaluating performance includingaverage inter-cluster similarity, speedup and processors' utilization. Simulation results show that theproposed algorithm improves performance, decreases the clustering time, and increases the overallspeedup while still keeping a high clustering quality. By increasing the number of processors, theclustering time decreases till a certain point where any more processors will no longer be effective.Moreover, the algorithm is applicable for different domains for other document collections.
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