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The fractal dimension is of ultimate importance in the description of the properties and behavior of microbial flocs in biological wastewater treatment systems. However, the methods for the measurement of the fractal dimension have not been well-established. In this study, a new method is developed to determine the fractal dimension of biological flocs in activated sludge (AS) suspensions. The new method utilizes the particle size distribution (PSD) of the sludge flocs measured by image processing under a microscope. Mechanical breakage is conducted for the sludge sample to create a change in the PSD. On the basis of the self-similarity of fractal aggregates, the fractal dimension of the AS flocs can be calculated from a comparison between the original PSD and the altered PSD by breakage. Itis determined that the sludge flocs grown in laboratory bioreactors with sludge ages of 5, 10, and 20 days have fractal dimensions of 2.07, 2.21, and 2.36. The sludge collected from a full-scale AS treatment plant has a fractal dimension of 1.99. This new method overcomes the deficiencies of other existing methods. It is easier to use and provides more reliable results in the determination of the fractal dimension of biological flocs and other similar aggregate samples. [ABSTRACT FROM AUTHOR]

Introduction. Hypertension in association with diabetes (DM), renal impairment (RI), and left ventricular hypertrophy (LVH) increases the risk of future cardiovascular events. We hypothesize, traditional herbal medicines Danshen and Gegen (D&G) have beneficial effects on atherogenesis in these high-risk hypertensive subjects. Subjects and Methods. 90 asymptomatic hypertensive subjects associated with LVH (63.3%), DM (62.2%), or RI (30%) were randomized to receive D&G herbal capsules lgm/day, 2gm/day, or identical placebo capsules in double-blind and parallel fashion for 12 months. Brachial flow-mediated dilation (endothelium-dependent dilation, FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. All data were analyzed usingthe Statistical Package for Social Sciences in Windows 16.0. Results. Their mean age was 55 ± 8 years, and 74.4% were male. After 12 months of adjunctive therapies and compared with baseline, there were no significant changes in blood pressure, heart rate, hematological, glucose, and creatinine profiles in both placebo and D&G groups. FMD improved significantly during D&G (P = 0.0001) and less so after placebo treatment (P = 0.001). There was a mild but significant decrease in carotid IMT after D&G (P < 0.001) but no significant changes after placebo. A trend of better improvement in FMD after higher versus lower D&G dosages was seen. D&G were well tolerated, with no significant adverse events or blood biochemistry changes. Conclusion. D&G adjunctive treatment was well tolerated and significantly improved atherogenesis in high-risk hypertensive patients, with potential in primary atherosclerosis prevention. [ABSTRACT FROM AUTHOR]