The effectiveness of using magnetic resonance imaging in syncope patients visiting an emergency department: A case-control study.

OBJECTIVE: To evaluate the effectiveness of brain magnetic resonance imaging in excluding neurological causes in patients with syncope. METHODS: This retrospective, observational, cohort study was conducted at the Chonnam National University Hospital, Gwangju, South Korea, and comprised medical record of patients with syncope from January 2011 to February 2016. The ratio of abnormal findings, the characteristics of the patients who showed abnormal findings and the relationships between the presence of neurological problem and other clinical factors were analysed. SPSS 18 was used for statistical analysis. RESULTS: Of the 1,045 patients, 142(13.5%) underwent additional magnetic resonance imaging. The results showed that 15(10.6%) patients had abnormal findings indicating neurological problems; of them, 9(60%) showed vascular stenosis, 4(27%) showed cerebral infarction, and 2(13%) showed brain tumours. The neurological problems shown were significantly higher for older patients (p=0.006) and those with the underlying diseases of hypertension (p=0.014) and coronary artery disease (p=0.008). Of these patients in particular, age (p=0.036) and history of coronary artery disease (p=0.029) were significantly associated with abnormal findings in their magnetic resonance imaging. CONCLUSIONS: Although there are no specific neurological examinations or computed tomography findings currently used in patients with syncope in the emergency department, magnetic resonance imaging may be performed to exclude neurological causes in older patients as well as those with a history of coronary artery disease.

The effects of starvation on physical characteristics of flocs in SBR for treating saline wastewater.

This study focused on the effects of starvation on physical characteristics of flocs in SBR for treating saline wastewater. Feeding was stopped for 5 and 15 days. A time response of the floc to these starvation periods was monitored as well as the removal efficiencies of pollutants. Correlation between the physical characteristics of flocs and settling of sludge was conducted. As the starvation periods were increased, there was a shift in the floc size distribution from a high proportion of large flocs to the development of small size flocs. The fractal dimension of flocs also decreased, as starvation periods were increased. From the results, the effect of starvation on SBR treating saline wastewater can be ordered as follows: COD Mn removal < floc size and fractal dimension < T-N removal < T-P removal.

Effects of fill time on the fractal dimension and size of floc for SBR treating low C/N ratio wastewater.

The aim of this study was to investigate the effects of fill time of influent on the physical characteristics of biological floc for sequencing batch reactor (SBR) treating low C/N ratio wastewater. The fractal dimension and size of floc were measured for characterizing floc. The fractal dimension of floc was analyzed by using Small Angle Laser Light Scattering (SALLS) method. SBR with short fill time showed higher removal efficiencies of COD, BOD, T-N, and T-P than with long fill time. Larger floc size and fractal dimension were generated at SBR with short fill time. Short fill time generated the sludge with better settling and thickening properties. Alternating anaerobic and aerobic condition in the cycle also affected the floc size and fractal dimension. The floc size decreased under anaerobic phase, and floc size increased under aerobic phase. During fill time, the fractal dimension of floc decreased. As the fill stop, the fractal dimension of floc increased. Therefore, the fill time condition more affected the fractal dimension of floc. More efficient nitrification and phosphorus release were observed during a cycle with short fill time operation.