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Excessive blue light light-emitting diode (LED) exposure and consequent oxidative stress causes damage to retinal pigment epithelial (RPE) cells. Chitosan oligosaccharides (COSs) are the hydrolyzed products of chitin, which is abundant in the exoskeleton of crustaceans and cell walls of fungi. We investigated the protective effect of COSs on blue light LED-induced RPE cell damage. These cells were treated with various concentrations of COSs and then exposed to blue light LED. Our results confirmed that RPE cell apoptosis increased significantly with longer light exposure. Treatment with COSs significantly reduced apoptosis in a dose-dependent manner. These molecules also suppressed the production of reactive oxygen species and the expression of inflammation- and apoptosis-related proteins. Moreover, COSs stabilized the mitochondrial membrane potential of cells and down-regulated the NF-κB pathway. In this study, the protective effects of COSs on blue light LED-induced RPE cell damage, as well as the associated mechanisms, were demonstrated.

Segmentation of a fetal head from three-dimensional (3-D) ultrasound images is a critical step in the quantitative measurement of fetal craniofacial structure. However, two main issues complicate segmentation, including fuzzy boundaries and large variations in pose and shape among different ultrasound images. In this article, we propose a new registration-based method for automatically segmenting the fetal head from 3-D ultrasound images. The proposed method first detects the eyes based on Gabor features to identify the pose of the fetus image. Then, a reference model, which is constructed from a fetal phantom and contains prior knowledge of head shape, is aligned to the image via feature-based registration. Finally, 3-D snake deformation is utilized to improve the boundary fitness between the model and image. Four clinically useful parameters including inter-orbital diameter (IOD), bilateral orbital diameter (BOD), occipital frontal diameter (OFD) and bilateral parietal diameter (BPD) are measured based on the results of the eye detection and head segmentation. Ultrasound volumes from 11 subjects were used for validation of the method accuracy. Experimental results showed that the proposed method was able to overcome the aforementioned difficulties and achieve good agreement between automatic and manual measurements.

Polymerase chain reaction analysis in combination with denaturing gradient gel electrophoresis (DGGE) was used to determine changes in the composition of the bacterial community of a bioreactor during ammonia removal. A minimum of 13 bands were observed in the DGGE profile. Phylogenetic analysis revealed that phylum Proteobacteria was predominantly represented in the bacterial community of the bioreactor, followed by Firmicutes , Actinobacteria , and Flavobacteriaceae . However, the occurrence and predominance of specific bacterial species varied with the concentrations of NH 3 introduced into the bioreactor. The complexity of the bacterial species generally decreased with increasing inlet NH 3 concentration. Based on the characteristics of the identified species, there is a potential for nitrification, denitrification, nitrate reduction, nitrite reduction, and ammonia assimilation to occur simultaneously in the bioreactor. The strains identified in this study are potential candidate strains for the purification of waste gases containing high concentrations of NH 3 .