Evaluation of hybrid processes for nitrification by comparing MBBR/AS and IFAS configurations.

An integrated fixed-film activated sludge (IFAS) pilot plant and a moving bed biofilm reactor coupled with an activated sludge process (MBBR/AS) were operated under different temperatures, carbon loadings and solids retention times (SRTs). These two types of hybrid systems were compared, focusing on the nitrification capacity and the nitrifiers population of the media and suspended biomass alongside other process performances such as carbonaceous and total nitrogen (TN) removal rates. At high temperatures and loadings rates, both processes were fully nitrifying and achieved similarly high carbonaceous removal rates. However, under these conditions, the IFAS configuration performed better in terms of TN removal. Lower temperatures and carbon loadings led to lower carbonaceous removal rates for the MBBR/AS configuration, whereas the IFAS configuration was not affected. However, the nitrification capacity of the IFAS process decreased significantly under these conditions and the MBBR/AS process was more robust in terms of nitrification. Ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) population counts accurately reflected the changes in nitrification capacity. However, significantly less NOBs than AOBs were observed, without noticeable nitrite accumulation, suggesting that the characterisation method used was not as sensitive for NOBs and/or that the NOBs had a higher activity than the AOBs.

Fracture interpretation using electronic presentation: a comparison.

The purposes of this study were to determine whether (1) fractures are interpreted differently after digitization and electronic presentation; (2) there are differences in accuracy between screen radiographs and electronic presentation; (3) differences in interpretation are a function of monitor resolution; and (4) differences in interpretation between radiographs and electronic images relate to radiological subspecialty. Forty cases with fractures of varying degrees of subtlety and 35 cases without fractures were interpreted. Radiographs were digitized with 2 different systems and displayed on 3 monitors of different spatial resolution. Four radiologists, with varying experience, were asked to decide whether fractures were present, absent, or they were uncertain. Accuracy of interpretation increased with improved electronic image presentation and monitor resolution. The sensitivity, specificity, and accuracy of fracture detection on System A were 63%, 98%, and 78%, respectively. The results were 72%, 98%, and 84% with System B. System C results were 81%, 97%, and 88% with Lumiscan 75, and 82%, 96%, and 88% with Lumiscan 150. Sensitivity, specificity, and accuracy results of the original radiograph interpretation were 89%, 95%, and 92%. Results were significantly different for System A. No significant differences were found for the other systems compared with film radiographs. System A did not have adequate monitors for interpretation of subtle fractures. Systems B and C were capable of displaying even subtle fractures. Our initial results indicate that interpretation with high-quality 1K x 1K monitors is substantially similar to radiograph interpretation.

Granuloma annulare: radiographic demonstration of progressive mutilating arthropathy with vanishing bones.

Granuloma annulare, a relatively common cutaneous disorder of unknown origin, is named for its predominantly papular lesions, which tend to group and coalesce in an annular fashion. Clinically distinct subtypes are divided into localized, generalized, perforating, and subcutaneous forms. Only the superficial granulomata of the extremities in subcutaneous granuloma annulare have been radiographically depicted in the literature. We describe and illustrate what we believe is the first radiographic presentation of bone and joint involvement with advanced, generalized granuloma annulare.

Erdheim-Chester disease: radiographic findings in five patients.

We present the case histories of five patients with Erdheim-Chester disease, a rare lipoidosis that has several typical radiographic features. In all the patients, the diaphyses and metaphyses of the extremities demonstrated a symmetric pattern of diffuse or patchy increased density, a coarsened trabecular pattern, medullary sclerosis, and cortical thickening. The epiphyses were spared in four patients and partially involved in one. The axial skeleton was involved in one patient. Radiotracer 99mTc accumulated in areas of radiographic abnormalities in all patients. In one patient, MRI demonstrated an abnormal signal, corresponding to radiographic abnormalities. The signal was hypointense to muscle on T1-weighted sequences and heterogeneously hyperintense and hypointense to normal bone marrow on T2-weighted sequences. Xanthogranulomatous lesions infiltrated the retroperitoneum in one patient, the testes in one patient, the eyelids in one patient, and the orbits in two patients.