Full-range depth-encoded swept source polarization sensitive optical coherence tomography.

To realize the high sensitivity polarization sensitive optical coherence tomography (PS-OCT) imaging, a fiber-based full-range depth-encoded swept source PS-OCT (SS-PS-OCT) method is proposed. The two OCT images corresponding to the orthogonal polarized input light are located on the high sensitivity imaging region of the opposite sides relative to the zero optical path difference position. The full-range OCT images can be obtained by implementing the spatial phase modulation in the reference arm. The detection sensitivity of the system was measured experimentally to be 67 dB when the imaging depth approaching to 2 mm. The imaging of the biological tissue verifies that the proposed full-range depth-encoded SS-PS-OCT system has the higher detection sensitivity compared with the conventional depth encoded SS-PS-OCT system. Finally, we demonstrated the full-range high sensitivity phase retardation image of the bovine tendon and skin of human fingertip. The fiber-based full-range depth-encoded SS-PS-OCT method can realize the high sensitivity birefringence imaging in the medical diagnosis scenes with the requirements for long imaging range and high detection sensitivity.

Protective Effect of Protocatechuic Acid on Oxidative Damage and Cognitive Impairment in Pb-Induced Rats.

Protocatechuic acid (PCA), a class of water-soluble phenolic acid abundant in the human diet, has been shown to be of great nutritional interest and to have medicinal value. However, the protective effects against lead (Pb)-induced body injury have not been elucidated. In this study, we explored the protective effect of PCA on Pb-induced oxidative damage and cognitive impairment in rats. The results showed that PCA could reduce the Pb content in rat bodies (blood, bone, brain, liver, and kidney) after Pb exposure. Moreover, PCA may inhibit Pb-induced oxidative damage by increasing the activity of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreasing the level of malondialdehyde (MDA) in the brain, liver, and kidney. In addition, PCA may alleviate Pb-induced learning and memory impairment by upregulating neurotransmitter levels; maintaining the normal function of N-methyl-D-aspartate receptors (NMDARs); and promoting Ca2+ influx, thus activating signaling molecules, related protein kinases, and transcription factors in the cAMP-PKA-CREB pathway. In general, PCA could reduce oxidative stress and ameliorate the learning and memory deficits in Pb-treated rats, indicating that PCA may be an effective preventive agent and treatment or plumbism.