RESUMO
Experimental studies have shown that exercise and human adipose-derived stem cells (ADSCs) play positive roles in spinal cord injury (SCI). However, whether ADSCs and/or exercise have a positive effect on SCI-induced neuropathic pain is still unclear. Thus, there is a need to explore the effects of exercise combined with administration of ADSCs on neuropathic pain after SCI. In this study, a thoracic 11 (T11) SCI contusion model was established in adult C57BL/6 mice. Exercise was initiated from 7 days post-injury and continued to 28 days post-injury, and approximately 1 × 105 ADSCs were transplanted into the T11 spinal cord lesion site immediately after SCI. Motor function and neuropathic pain-related behaviors were assessed weekly using the Basso Mouse Scale, von Frey filament test, Hargreaves method, and cold plate test. Histological studies (Eriochrome cyanine staining and immunohistochemistry) were performed at the end of the experiment (28 days post-injury). Exercise combined with administration of ADSCs partially improved early motor function (7, 14, and 21 days post-injury), mechanical allodynia, mechanical hypoalgesia, thermal hyperalgesia, and thermal hypoalgesia. Administration of ADSCs reduced white and gray matter loss at the lesion site. In addition, fewer microglia and astrocytes (as identified by expression of ionized calcium-binding adapter molecule 1 and glial fibrillary acidic protein, respectively) were present in the lumbar dorsal horn in the SCI + ADSCs and SCI + exercise + ADSCs groups compared with the sham group. Our findings suggest that exercise combined with administration of ADSCs is beneficial for the early recovery of motor function and could partially ameliorate SCI-induced neuropathic pain.
RESUMO
The photoactivity of nanoporous bismuth vanadate (BiVO4, BVO) photoanodes that were fabricated by a two-step process (electrodeposition and then thermal conversion) in photoelectrochemical (PEC) hydrogen (H2) evolution can be enhanced about 1.44-fold by improving the constitutive ratio of (111Ì ), (061), and (242Ì ) crystal facets. The PEC characterization was carried out to investigate the factors altering the performance, which revealed that the crystal facet modulation could improve the photoactivity of the BVO photoanodes. In addition, the orientation-controlled BVO thin-film electrodes are introduced as evidence that the present crystal facet modulation is the positive effect for BVO photoanodes in PEC. The investigation of energy band structures and interfacial charge carrier dynamics of the BVO photoanodes reveals that the crystal facet modulation could result in a shorter lifetime of charge carrier recombination and larger band bending at the interface between BVO and electrolytes. This outcome could improve the charge separation and charge transfer efficiencies of BVO photoanodes, promoting the efficiency of PEC H2 evolution. Moreover, this crystal facet modulation can combine with co-catalyst decoration to further improve the solar-to-hydrogen efficiency of BVO photoanodes in PEC. This study presents a potential strategy to promote the PEC activity by crystal facet modulation and important insights into the interfacial charge transfer properties of semiconductor photoelectrodes for the application in solar fuel generation.
RESUMO
Titanium dioxide (TiO2) nanorods (NRs) are widely used as photoanodes in photoelectrochemical (PEC) solar fuel production because of their remarkable photoactivity and stability. In addition, TiO2 NR electrode materials can be decorated with active CdS quantum dots (QDs) to expand the sunlight photon capture. The overall photoelectric conversion efficiency for TiO2 NR or QD-sensitized TiO2 NR electrode materials in PEC is typically dominated by their interfacial electron transfer (ET) properties. To understand the key factors affecting the ET, the anatase TiO2 seed layer was added into the interface between the rutile TiO2 NRs and fluorine-doped tin oxide (FTO) substrate. This seed layer enhanced the photocatalytic performance of both the TiO2 NR and CdS QD-sensitized TiO2 NR photoanodes in PEC. Time-resolved photoluminescence spectroscopy and PEC analyses, including Mott-Schottky, electrochemical impedance spectroscopy, and photovoltage ( Vph) measurements, were used to study the charge-carrier dynamics at the interfaces between the FTO, TiO2, and CdS QD. Analysis of the results showed that band alignment at the anatase/rutile junction between the TiO2 and FTO promoted electron-collection efficiency ( eEC) at the FTO/TiO2 interface and ET rate constant ( kET) at the TiO2/CdS QD interface. Furthermore, 34% enhancement of the efficiency in hydrogen (H2) generation demonstrated the potential of the TiO2 seed-layer-mediated TiO2/CdS QD NR photoanode in the application of PEC solar fuel production. The current work represents new insights into the mechanism of ET in TiO2 and TiO2/CdS QD NR, which is very useful for the development of photoelectrode materials in solar energy conversions.