Highly permeable tubular silicalite-1 membranes for CO2 capture.

Membranes represent one of the most promising alternatives for CO2 separation and capture. Zeolites membranes, in particular, that can withstand high temperatures and pressures, offer energy efficient way to capture CO2 compared to conventional separation techniques such as amine absorption. In this work, silicalite-1/ceramic composite membranes were prepared on the inner surface of zirconium oxide and/or titanium oxide tubular supports by a pore plugging hydrothermal synthesis. Five types of supports with different pore sizes ranging from 0.14 to 1.4 µm, were studied. The synthesized membranes were characterized by scanning electron microscope (SEM), electron diffraction spectrometer (EDS), x-ray diffraction (XRD), and gas permeation with pure and mixed gas feeds. All membranes showed high concentrations of Si within the active layer of the support, suggesting successful pore-plugging of the membranes. The greater the pore size of the active layer of the support, the greater was the concentration of Si observed. In addition, large coffin-shape crystals, which are characteristics of silicalite-1, were also observed on top of each membrane. The analysis of XRD micrographs revealed that the crystals were mostly oriented with either the a- or b-axes perpendicular to the membrane surface, which is desirable from the point of view of minimizing the resistance to gas transport through the zeolite membrane. Except for the membranes synthesized using the supports with 0.14 µm pores, all membranes were very selective with CO2/N2 permselectivities up to 30 at low-pressure differentials. At the same time, the membranes were very permeable with CO2 permeance in the order of 10-6 mol m-2 Pa-1 s-1. Assuming the thickness of the selective layer to be equivalent to the thickness of the active layer of the support, all membranes fell above the revised Robeson upper-bound line for CO2/N2 separation.

Temporomandibular disorders in patients with mandibular fractures: a preliminary comparative case-control study between South Australia and Oman.

The status of temporomandibular disorders (TMD) in subjects with previously treated mandibular fracture was evaluated in two centres: South Australia (SA) and Oman (O). TMD status was evaluated using Mandibular Function Impairment Questionnaire (MFIQ), Helkimo index for clinical dysfunction (HI), RDC/TMD and Wilkes' classification. Data were retrieved for adult patients treated for mandibular fracture over 3 years from January 2004 to December 2006. Thirty-six subjects participated from SA and 23 from O. Their results were compared with matched controls. The incidence of TMD symptoms in SA injured and control groups was higher compared with the O groups. There was statistically significant difference on all evaluation indices for SA injured subjects compared with controls (MFIQ/P 0.04, HI/P 0.0015, RDC/TMD/P 0.05, Wilkes classification/P 0.03). These TMD symptoms were clinically insignificant for most subjects and all were internal derangement of the temporomandibular joint (TMJ). There was no significant difference in all evaluation indices for O injured subjects compared with controls. For SA injured subjects who reported clinically significant TMD symptoms, assault and bilateral mandibular fractures were predominant features. The study shows that most mandibular injuries fully recover and the associated TMJ trauma usually has low clinical significance in the long term.

Prevalence of dental caries in Omani 6-year-old children.

OBJECTIVE: To determine the prevalence of dental caries in Omani 6-year-old children. DESIGN: Clinical caries cross-sectional survey, conducted by 16 trained and calibrated dentists. SETTING: Omani primary schools in December 1994. SUBJECTS: 3,114 subjects, randomly selected to achieve an overall 6.6 per cent sample of Omani 6-year-old children. OUTCOME MEASURES: Caries diagnosis based solely on clinical examination in accordance with criteria of British Association for the Study of Community Dentistry. RESULTS: Only 484 subjects (15.5 per cent) were caries-free; regional variations ranging from 4.4 per cent to 31 per cent. Overall, the national dmft averaged 4.61; the majority of caries experienced being in the form of untreated decay, with occlusal surfaces of first primary molars being the most commonly involved site. CONCLUSIONS: Compared with results from a survey of Omani 12-year-old children in 1993, a much smaller proportion of this 6-year-old sample were caries free, emphasising the need for continuance of existing, and the development of further, preventive programmes.

The oral health status of Omani 12-year-olds--a national survey.

This study reports the first ever national oral health survey of Omani 12-year-olds. Conducted in October 1993, of the 3,435 children examined, 1,438 (41.9%) were caries-free, although regional variations ranged from 24.8% to 61.9%. Overall, the national DMFT averaged 1.53, the majority of caries experienced being in the form of untreated decay, with occlusal surfaces of first permanent molars being the most commonly involved site. Oral hygiene was poor, only 11% of those examined being scored as plaque-free.

Oral myiasis: report of two cases.

Case reports are presented of two patients from Oman who developed myiasis in the palate. Both suffered from cerebral palsy and had incompetent lips, anterior open bite and very poor oral hygiene. Both patients had denuded areas of hard palate anteriorly. In both cases large numbers of maggots were found under the surrounding mucoperiosteam. Removal of the maggots and debridement resulted in resolution of the condition.