Synergistically promoted charge separation/transfer in a ZnO nanosheet photoanode via the incorporation of multifunctional 3DrGO.

Herein, we report a robust strategy to markedly promote charge separation and transfer via electrodepositing ZnO nanosheets into a cross-linked porous three-dimensional reduced graphene oxide (3DrGO) network structure to form a ZnO/3DrGO photoanode. In addition to the high electrical conductivity and 3D porous architecture, the photothermal effect of 3DrGO activated by a near-infrared (NIR) laser or NIR light of solar radiation can be used to increase the temperature of the photoanodes in situ, further enhancing the charge transfer efficiency of ZnO nanosheets. With the synergistic effect of 3DrGO, the photocurrent density of the ZnO/3DrGO photoanode (2.03 mA cm-2) is about three times higher than that of the pure ZnO photoanode (0.51 mA cm-2) at 1.23 V vs. reversible reference electrode (VRHE). This work provides an effective strategy for improving the PEC water splitting performance of photoanodes via the incorporation of multifunctional 3D porous architecture rGO.

Harvesting the infrared part of solar light to promote charge transfer in Bi2S3/WO3 photoanode for enhanced photoelectrochemical water splitting.

Infrared light absorbed by semiconductors hardly contributes to the solar energy conversion due to its low photon energy. Herein, photothermal effect activated by infrared part of solar light is introduced to promote the photoelectrochemical (PEC) water splitting of photoanodes. Narrow band-gap semiconductor Bi2S3 is deposited on the surface of WO3 nanosheets, exhibiting a broad-spectral response. In addition to the enhanced density of photo-generated electrons, significant temperature elevation is observed for the Bi2S3/WO3 composite photoanode under the illumination of infrared part of solar light because of the photothermal conversion property of Bi2S3. The moderately enhanced temperature accelerates charge carrier migration and finally increases the efficiency of solar energy conversion. With the assistance of photothermal effect, a remarkable photocurrent density of 4.05 mA cm-2 at 1.23 V vs. reversible reference electrode (VRHE) is achieved by Bi2S3/WO3 composite photoanode, over 880% higher than that of the pristine WO3. The introduction of photothermal effect activated by infrared light provides general and robust strategy to promote the PEC performance of photoanodes.

[Effect of cervical disc arthroplasty and anterior cervical decompression and fusion on adjacent segment degeneration].

OBJECTIVE: To compare the effect on adjacent segment degeneration after cervical disc arthroplasty (CDA) and anterior cervical decompression and fusion (ACDF) for treatment of cervical spondylosis. METHODS: Between August 2009 and February 2012, 60 cases of single segmental cervical spondylosis accorded with the inclusion criteria were included. Of 60 patients, 28 patients underwent CDA (CDA group) and 32 patients underwent ACDF (ACDF group). There was no significant difference in gender, age, disease duration, pathological type, pathological segment, the time of conservation treatment, preoperative neck disability index (NDI), preoperative Japanese Orthopaedic Association (JOA) score, and degeneration of the adjacent segment and disc between 2 groups (P > 0.05). The NDI and JOA score were used to evaluate effectiveness. The range of motion (ROM) of adjacent segment was measured, and degeneration of the adjacent segment and disc was evaluated according to Kellgren grading system based on X-ray and Miyazaki grading system based on T2-weighted MRI, respectively. RESULTS: The follow-up time was 24-50 months (mean, 34 months) in 2 groups. All patients had no complication of prosthesis loosening, dislocation, or fracture of plate. The NDI and JOA scores from 12 months after operation were significantly improved compared with preoperative scores in 2 groups (P < 0.05), but no significant difference was found at each time point between 2 groups (P > 0.05). The improvement rate of JOA was 80.68% ± 4.01% in ACDF group and was 79.44% ± 3.76% in CDA group at last follow-up, showing no significant difference (t = -1.237, P = 0.221). And the improvement rate of JOA in 2 groups were excellent. There was no significant difference in ROM and degeneration grading of adjacent segments between at last follow-up and at pre-operation in 2 groups (P > 0.05), and between 2 groups at pre-operation and at last follow-up (P > 0.05). The degeneration grading of disc at last follow-up showed significant difference in 2 groups compared with preoperative ones (P < 0.05), but no significant difference was found between 2 groups (Z = 0.132, P = 0.895). CONCLUSION: Both CDA and ACDF can achieve good effectiveness in treating cervical spondylosis, but CDA can not significantly slow down the degeneration of adjacent segment disc.

[EXPRESSIONS OF TRANSFORMING GROWTH FACTOR ß1 AND CONNECTIVE TISSUE GROWTH FACTOR IN HUMAN LUMBAR INTERVERTEBRAL DISCS IN DIFFERENT DEGREES OF DEGENERATION].

OBJECTIVE: To investigate the role of transforming growth factor ß1 (TGF-ß1) and connective tissue growth factor (CTGF) in pathogenesis and progression of human intervertebral disc degeneration by detecting the expressions of these two factors in different degrees of degenerative discs. METHODS: The lumbar intervertebral discs were collected from 33 patients with lumbar disc herniation and 12 patients with lumbar vertebral fracture between November 2012 and April 2013. All samples were observed under the microscope after HE staining, and then were divided into different subgroups according to the degenerative degree. The expressions of TGF-ß1 and CTGF were detected by Western blot. RESULTS: According to the pathological features, 10 discs were defined as normal discs, 10 as mild degenerative discs, 9 as moderate degenerative discs, and 16 as severe degenerative discs. The histological observation showed that rounded nucleus pulposus cells with similar size evenly distributed in the cartilage-like matrix, and no hyperplastic collagenous fiber was seen in normal discs; mild degenerative discs characterized by slightly larger nucleus pulposus cells in the matrix, but cells did not decrease, a small quantity of inflammatory cells infiltrated in the matrix, hyperplasia of collagenous fiber was not seen; most of the nucleus pulposus cells became bigger, some showed a bulb form, the number of nucleus pulposus cells was significantly reduced, low grade hyperplasia of collagenous fiber emerged in the matrix, new vessels and inflammatory cells were both found in some specific areas of discs in moderate degenerative discs; there was no nucleus pulposus cells in the matrix of severe degenerative discs, the hyperplasia of collagenous fiber was obvious. The relative expression of TGF-ß1 in 3 degeneration discs was significantly higher than that in normal discs (P < 0.05), and the expression of TGF-ß1 was significantly higher in severe degenerative discs than in moderate and mild degenerative discs (P < 0.05), but no significant difference between moderate and mild degenerative discs (P > 0.05). The relative expression of CTGF in moderate and severe degeneration discs was significantly higher than that in normal discs (P < 0.05); and the expression of CTGF in mild degenerative discs was higher than that in normal discs, but there was no significant difference (P > 0.05); and significant difference in CTGF expression was found among 3 degeneration discs (P < 0.05). CONCLUSION: The expressions of TGF-ß1 and CTGF are closely related to the degree of human lumbar disc degeneration, these two factors may play an important role in promoting lumbar intervertebral disc degeneration.