Mohamed Sayed - Academia.edu (original) (raw)

Papers by Mohamed Sayed

Journal of American Association for Pediatric Ophthalmology and Strabismus

To determine the diagnostic value of B-scan echography in optic nerve head (ONH) cupping estimati... more To determine the diagnostic value of B-scan echography in optic nerve head (ONH) cupping estimation in children. The medical records of pediatric patients who had previously undergone examination under anesthesia and for whom both adequate B-scan echography images and optic nerve head (ONH) photographs and were available were reviewed retrospectively. The cup:disk ratio was estimated with a grading scale of 0-1.0 and rounded to the nearest tenth; degree of cupping was estimated from B-scan echography (small, medium, or large) by 5 masked graders (3 glaucoma specialists and 2 ophthalmic sonographers) on 2 separate occasions. Inter- and intraobserver agreement in echographic and photographic cupping assessment by the masked graders as well as correlation of echographic and photographic cup size estimation was evaluated. A total of 36 children were included. Glaucoma specialists reliably assessed cup:disk ratio with moderately good consistency across specialists (average intraclass correlation coefficient [ICC] for intraobserver agreement, 0.86; average ICC for interobserver agreement, 0.71). Sonographers were extremely reliable in assessment of cup size when examining echographic images (ICC for both inter- and intrarater variability, 1.0). Echographic estimate of cup size correlated poorly with cup:disk ratio (ICC, 0.34). B-scan echography is a reliable and consistent diagnostic tool in estimating the degree of ONH cupping in children and can be very useful in patients in whom direct visualization is not feasible. Failure to account for disk size may have contributed to the poor correlation between echographic cup size and photographic cup:disk ratio.

Plastic and Reconstructive Surgery - Global Open, 2016

Journal of diabetes, Jan 4, 2016

Little is known about level of glycemic control and risk factors of uncontrolled hyperglycemia in... more Little is known about level of glycemic control and risk factors of uncontrolled hyperglycemia in Saudi children with type 1 diabetes mellitus (T1DM). This study was done to identify level of glycemic control, risk factors and predictors of uncontrolled hyperglycemia (HG) and (DKA) in children with T1DM. A retrospective study included Saudi children and adolescents with confirmed T1DM who were followed at pediatric endocrinology clinic of Maternity and Children Hospital, Jeddah from 2000 to 2014. Data collection included all possible factors that may be associated with uncontrolled T1DM. Patients were classified according to American Diabetes Association guidelines for target HbA1c levels per age group. Comparisons between well controlled (WC) patients, HG patients and DKA patients were done. Calculation of odds ratios and logistic regression allowed for estimation of each risk factor role in uncontrolled T1DM. Only 31.2 % of children and adolescents with T1DM were WC. Better glycem...

The present paper deals with the implementation and testing of an ice thickness redistribution mo... more The present paper deals with the implementation and testing of an ice thickness redistribution model, which is intended for operational use by the Canadian Ice Service (CIS). The model, developed by Savage (2002), is briefly reviewed. The emphasis of this paper is on the implementation in a Particle-In-Cell (PIC) ice dynamics formulation. The model accounts for the evolution of distributions of thickness and concentration of ice in response to mechanical deformation. This is accomplished without resorting to discrete ice categories. A method to incorporate ice growth from open water is also discussed. The results indicate that the model produces appropriate behaviour and trends.

Cold Regions Engineering, 2002

Information Systems Applications in the Arab Education Sector, 2013

Abstract: First-year sea ice pressure ridges are modelled as two-dimensional wedges of a Mohr-Cou... more Abstract: First-year sea ice pressure ridges are modelled as two-dimensional wedges of a Mohr-Coulomb material and the passive stress distribution is obtained using a similarity solution and approximate polynomial forms of the dependent variable. Analysis gives the ...

New Phytologist, 2005

Bacteria were either isolated from leaf surfaces of Hedera helix or obtained from a culture colle... more Bacteria were either isolated from leaf surfaces of Hedera helix or obtained from a culture collection in order to analyse their effect on barrier properties of isolated Hedera and Prunus laurocerasus cuticles. On the basis of the 16S rDNA sequences the genera of the six bacterial isolates from Hedera were identified as Pseudomonas sp., Stenotrophomonas sp. and Achromobacter. Water permeability of cuticles isolated from H. helix was measured before and after inoculation with the six bacterial strains. In addition water permeability of cuticles isolated from P. laurocerasus was measured before and after inoculation with the three bacterial strains Pseudomonas aeruginosa, Xanthomonas campestris and Corynebacterium fascians. Rates of water diffusing across isolated cuticles of both species significantly increased by up to 50% after inoculation with all bacterial strains. Obtained results show that epiphytic bacteria have the ability of increasing water permeability of Hedera and Prunus cuticles, which in turn should increase the availability of water and dissolved compounds in the phyllopshere. Consequently, living conditions in the habitat phyllosphere are improved. It can be concluded that the ability to change leaf surface properties will improve epiphytic fitness of leaf surface bacteria.

Journal of Physics: Conference Series, 2010

Low-frequency (LF) atmospheric-pressure plasma (APP) jets have been used for patterning of thin f... more Low-frequency (LF) atmospheric-pressure plasma (APP) jets have been used for patterning of thin fibronectin films deposited on a silicon (Si) wafer with the use of a metal stencil mask. Since fibronectin is an adhesion protein that can be found in the extracellular matrix (ECM), a micro-patterned fibronectin film may be used for arranging living cells in a desired pattern on a surface. Removal of fibronectin from the surface by plasma application was observed by Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy (AFM). It has been found that removal of fibronectin takes place even in the location away from the direct plasma jet application spot, which indicates that desorption of fibronectin is likely to be caused by chemically reactive charge-neutral species that can diffuse away from the plasma without emitting visible light.

Journal of Cellular Biochemistry, 1999

Two ribosomal protein S6 kinases (i.e., pp52(S6K) and pp70(S6K)) of the p70 S6 kinase family were... more Two ribosomal protein S6 kinases (i.e., pp52(S6K) and pp70(S6K)) of the p70 S6 kinase family were markedly activated during meiotic maturation of Pisaster ochraceus sea star oocytes. A rapid protocol was developed for the purification from the oocyte cytosol of pp52(S6K) by approximately 50,000-fold with a specific enzyme activity of 1.6 micromol per min per mg. The purified enzyme apparently featured the N- and C-terminal regions of pp70(S6K) as it immunoreacted with antibodies directed to peptides patterned after these amino acid sequences in mammalian pp70(S6K). pp52(S6K) was inhibited by fluoride (IC(50) approximately 60 mM), but was relatively insensitive to beta-glycerolphosphate, EGTA, dithiothreitol, spermine, heparin, NaCl, and metal ions such as Mn(2+), Zn(2+), and Ca(2+). The consensus sequence for substrate phosphorylation was determined to be RXXSXR, which was partially distinct from mammalian p70(S6K) in its requirement for an amino-terminal arginine. Phosphorylation of ribosomal protein S6 by p52(S6K) occurred exclusively on serine on at least five tryptic peptides. Inhibition of sea star p52(S6K) phosphotransferase activity after treatment with protein serine/threonine phosphatases confirmed that p52(S6K) was still regulated by phosphorylation. The sea star S6 kinase was purified to near homogeneity with the regulatory and catalytic subunits of protein-serine phosphatase 2A and the heat shock protein 60. The association of an S6 kinase with phosphatase 2A was confirmed by coimmunoprecipitation of S6 kinase activity with phosphatase 2A-specific antibodies. The purified S6 kinase and the sea star oocyte system will be useful for analysis of upstream and downstream signaling events that lead to phosphorylation of the S6 protein and other targets.

Endocrinology and Metabolism Clinics of North America, 2008

Canadian Geotechnical Journal, 1986

Measurements of horizontal movements of the ice cover near Adams Island, March to June 1983, and ... more Measurements of horizontal movements of the ice cover near Adams Island, March to June 1983, and in Eclipse Sound, December 1982 to June 1983, indicate no apparent coupling between movement direction and wind or current. Average strain rates in the plane of the ice cover were 10−10 s−1, with a maximum of 10−8 s−1. Similar strain rate values were obtained on Eclipse Sound. Movement rates at Eclipse Sound were of the same magnitude as those at Adams Island, but the direction was quite different. Maximum calculated and measured ice pressures were 500 and 140 kPa, respectively. Key words: ice movements, ice pressures, Canadian Arctic Ocean, oceanography, wind.

Preoperative F-18 FDG PET/CT study in this 57-year-old woman showed an FDG avid lesion in the lef... more Preoperative F-18 FDG PET/CT study in this 57-year-old woman showed an FDG avid lesion in the left upper lung without evidence of lymphadenopathy or distant metastasis. She underwent a left upper lobectomy in June 2005 revealing moderately poorly differentiated adenocarcinoma (pT3N0M0) and subsequent chemotherapy completed December 2005. Nine months later, a left parietal lobe metastatic lesion was surgically resected. A true whole body FDG PET/CT study in November 2006 for restaging demonstrated new FDG avid spinal cord foci, which were highly suspicious for spinal cord metastases; these lesions were confirmed by MRI. Clinically, the patient recently developed back pain without evidence of neurologic deficits.