Correct manipulation method of MBR operating parameters in membrane fouling studies.

In this study, various parameter manipulation methods, variable sludge retention time (SRT)-variable mixed liquor suspended solids (MLSS) concentration, constant SRT-variable MLSS concentration and variable SRT-constant MLSS concentration, were compared based on the interrelationships among the following membrane bioreactor operating parameters: SRT, food to microorganisms (biomass) (F/M) ratio, MLSS concentration, volumetric organic loading rate (OLR) and membrane flux. Although it is the most applied method, concurrent change of SRT (or F/M ratio) and MLSS concentration is not a good parameter manipulation method because it causes unnecessary changes in many other parameters such as viscosity, oxygen transfer efficiency and oxygen utilization rate. The method of constant SRT-variable MLSS concentration has similar disadvantages to the method of variable SRT-variable MLSS concentration. The best alternative parameter manipulation method to study membrane fouling is the method of variable SRT-constant MLSS concentration because this method eliminates unnecessary changes in other parameters. In addition, while changing OLR or hydraulic retention time (HRT), contrary to the common application, membrane flux should be kept constant because any change in flux overrides changes in other parameters. Accordingly, required changes in OLR or HRT should be made by adjusting membrane area rather than membrane flux.

Brucellar arthritis of knee in a child.

A 15-month-old boy was admitted with fever and a swollen knee. His mother had been treated for brucellosis 11 months ago. At that time he had been asymptomatic and had both negative blood culture and serum agglutination tests and breastfeeding had been stopped. The infant had been healthy since then. On admission, blood and joint fluid were obtained for culture and he was commenced on cefuroxim. Gram-negative coccobacillary organisms were seen in the joint fluid. Both cultures remained sterile. He had a positive serum agglutination test with a titer of 1/640. Cefuroxim was then stopped and the child was commenced on a specific course of treatment: gentamicin, trimethoprim-sulfamethoxazole and rifampicin. The infant recovered with this treatment. We conclude that this was brucellar arthritis of the knee and was probably acquired by breastmilk after an exceptionally long incubation period.

Fulminant hepatic failure and autoimmune hemolytic anemia associated with Epstein-Barr virus infection.

Acute hepatic failure has been reported in the presence of Epstein-Barr virus (EBV) infection. Autoimmune hemolytic anemia may also occur in the course of this infection. We report a rare case of fulminant hepatic failure and autoimmune hemolytic anemia associated with Epstein-Barr virus. A seven-year-old girl was admitted with the complaints of abdominal pain, vomiting and jaundice. She was irritable, confused and had mild hepatomegaly with marked splenomegaly. Serum aminotransferase levels were moderately elevated, while direct and indirect bilirubin levels were markedly elevated. Prothrombin time was prolonged. Hemoglobin was 3.9 g/dl. Anti-HAV IgM, HbsAg, anti-HBc IgM, anti-HCV and anti-CMV IgM were negative, while IgM VCA EBV, IgG VCA EBV and anti-CMV IgG were positive. Serum copper and ceruloplasmin levels were normal. The patient received supportive therapy for hepatic failure. Meanwhile, the cause of the deep anemia was investigated and autoimmune hemolytic anemia was ascertained by means of increased reticulocyte count and positive Coombs test. Corticosteroid therapy was administered. The prognosis was good. Although not reported before, the combination of acute hepatic failure and autoimmune hemolytic anemia may complicate the course of EBV infection. Physicians need to be aware of this association.