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S M El-Sheikh

Publications and source records attributed to S M El-Sheikh.

2 recordsLinked to original sources

Phase transitions of methane using molecular dynamics simulations.

Using a short ranged Lennard-Jones interaction and a long ranged electrostatic potential, CH4 under high pressure was modeled. Molecular dynamics simulations on small clusters (108 and 256 molecules) were used to explore the phase diagram. Regarding phase transitions at different temperatures, our numerical findings are consistent with experimental results to a great degree. In addition, the hysteresis effect is displayed in our results.

Journal Article↗

Bacteria and viruses that cause respiratory tract infections during the pilgrimage (Haj) season in Makkah, Saudi Arabia.

OBJECTIVE: To determine the incidence and type of RTI-causing bacteria and viruses during a period of epidemic infections. METHOD: A total of 395 sputum specimens and 761 throat swabs were collected during the 1991 and 1992 pilgrimage seasons (Haj to Makkah Al-Mukarama, Saudi Arabia) from patients referred to one hospital and three dispensaries with symptoms of respiratory tract infections. All 761 throat swabs of both Haj seasons were also screened for the presence of viral pathogens with monoclonal antibodies specific for 7 viruses known to cause respiratory infections. RESULTS: Bacterial pathogens were detected in 118 (29.9%) specimens. During the 1991 Haj season Haemophilus influenzae was the most frequent bacterial pathogen detected (10%), followed by Klebsiella pneumoniae (5.2%), Streptococcus pneumoniae (4.8%), Staphylococcus aureus (3.8%) and Streptococcus pyogenes (2.4%). In the 1992 Haj season Klebsiella pneumoniae was predominant (15.1%), followed by Haemophilus influenzae and Streptococcus pneumoniae (12.3%). Screening of all sputum specimens for acid-fast bacteria showed that the overall incidence rate of tuberculosis was 1%. Cultures from the 761 throat swabs were largely negative for bacteria except for Streptococcus pyogenes isolated from 7 patients. Viruses were detected in 148 (19.5%) specimens with influenza A and adenovirus being the most common viruses. CONCLUSION: The pattern of virus prevalence in the 1991 and 1992 pilgrimage seasons was identical: influenza A and adenovirus predominated. Thus these two viruses should be targeted in future prophylactic measures.

Antibodies, Monoclonal↗