Towards the Design and Implementation of an Image-Based Navigation System of an Autonomous Underwater Vehicle Combining a Color Recognition Technique and a Fuzzy Logic Controller.

This study proposes the development of an underwater object-tracking control system through an image-processing technique. It is used for the close-range recognition and dynamic tracking of autonomous underwater vehicles (AUVs) with an auxiliary light source for image processing. The image-processing technique includes color space conversion, target and background separation with binarization, noise removal with image filters, and image morphology. The image-recognition results become more complete through the aforementioned process. After the image information is obtained for the underwater object, the image area and coordinates are further adopted as the input values of the fuzzy logic controller (FLC) to calculate the rudder angle of the servomotor, and the propeller revolution speed is defined using the image information. The aforementioned experiments were all conducted in a stability water tank. Subsequently, the FLC was combined with an extended Kalman filter (EKF) for further dynamic experiments in a towing tank. Specifically, the EKF predicts new coordinates according to the original coordinates of an object to resolve data insufficiency. Consequently, several tests with moving speeds from 0.2 m/s to 0.8 m/s were analyzed to observe the changes in the rudder angles and the sensitivity of the propeller revolution speed.

Bacterial cellulose and bacterial cellulose-chitosan membranes for wound dressing applications.

Bacterial cellulose (BC) and bacterial cellulose-chitosan (BC-Ch) membranes were successfully produced in large scale. BC was synthesized by Acetobacter xylinum. BC-Ch was prepared by immersing BC in chitosan followed by freeze-drying. The surface morphology of BC and BC-Ch membranes were examined by a scanning electron microscope (SEM). SEM images showed that BC-Ch possessed a denser fibril network with smaller pores than BC. Infrared spectroscopy was used to confirm the incorporation of chitosan in BC-Ch. The swelling behavior, water retention capacity, and mechanical properties of BC and BC-Ch were further evaluated. Results indicated that both membranes maintained proper moisture contents for an extensive period without dehydration. The tensile strength and elongation at break for BC-Ch were slightly lower while the Young's modulus was higher. Cell culture studies demonstrated that BC and BC-Ch had no cytotoxicity. In the antibacterial test, the addition of chitosan in BC showed significant growth inhibition against Escherichia coli and Staphylococcus aureus. The effects of BC and BC-Ch on skin wound healing were assessed by rat models. Histological examinations revealed that wounds treated with BC-Ch epithelialized and regenerated faster than those treated with BC or Tegaderm. Therefore, BC-Ch was considered as a potential candidate for wound dressing materials.

Investigation on the lipid- and cholesterol-lowering abilities of biocellulose.

The present study investigated and compared the physicochemical properties as well as the hypolipidemic and hypocholesterolemic effects between plant cellulose and biocellulose. Biocellulose had higher water-holding and cation-exchange capacities than plant cellulose ( approximately 2- and 6-fold, respectively). The results showed that the administration of plant cellulose and biocellulose to hamsters effectively ( P < 0.05) decreased the concentrations of serum triglyceride (by 13.9-55.5%), serum total cholesterol (by 17.4-27.9%), serum low-density lipoprotein cholesterol (by 41.9-47.9%), liver total lipids (by 6.4-10.3%), and liver cholesterol (by 11.8-16.3%). Feeding plant cellulose and biocellulose also enhanced the excretion of total lipids (144-182%), cholesterol (136-203%), and bile acids (259-479%) in feces. The efficacy of biocellulose in lowering serum lipids and cholesterol in hamsters was significantly higher than that of plant cellulose. These results suggested that biocellulose could be a promising low-calorie bulking ingredient for the development of novel fiber-rich functional foods of different forms such as powder, gelatinous, or shred forms.