RESUMO
After spinal cord injury, the concentrations of total and hyperphosphorylated tau in cerebrospinal fluid increase, and levels of both correlate with injury severity. Tau inhibition is considered effective therapy for many central nervous system diseases, including traumatic brain injury and Alzheimer's disease. However, whether it can play a role in the treatment of spinal cord injury remains unclear. In this study, the therapeutic effects of tau inhibition were investigated in a rat model of transection spinal cord injury by injecting the rats with a lentivirus encoding tau siRNA that inhibits tau expression. We found that tau inhibition after spinal cord injury down-regulated the levels of inflammatory mediators, including tumor necrosis factor-α, interleukin-6 and interleukin-1ß. It also led to a shift of activated microglial polarization from the M1 pro-inflammatory phenotype to the M2 anti-inflammatory phenotype, and reduced the amount of reactive oxygen species in the acute phase. Furthermore, the survival of residual neural cells around the injury epicenter, and neuronal and axonal regeneration were also markedly enhanced, which promoted locomotor recovery in the model rats. Collectively, our findings support the conclusion that tau inhibition can attenuate neuroinflammation, alleviate oxidative stress, protect residual cells, facilitate neurogenesis, and improve the functional recovery after spinal cord injury, and thus suggest that tau could be a good molecular target for spinal cord injury therapy.
RESUMO
To prevent the eutrophication of tributaries and guarantee water quality and safety in the Three Gorges Reservoir, research on the impact of mainstream backwater on tributary water environments is of great significance. The investigation and sampling of the Yangtze mainstream and its major tributaries in the reservoir region were performed from August 7 to August 12, 2016, through which the overall hydrochemical environment of the Three Gorges Reservoir has been revealed, and the impact of mainstream backwater on the hydrochemical characteristics of main tributaries has been determined during the low water level operation period. The results showed the following:â The electrical conductivity of the mainstream varied from 291 µS·cm-1 to 336 µS·cm-1, whereas that of the mainstream backwater unaffected zone of the tributary varied from 183.7 µS·cm-1 to 518 µS·cm-1. The electrical conductivity of the mainstream backwater affected zone of the tributary varied from 267 µS·cm-1 to 330 µS·cm-1, which was close to the mainstream variation range. â¡ The variation range of the δD and δ18 O values of the mainstream were -81.60--75.16 and -11.57--0.26, whereas that of the mainstream backwater unaffected zone of tributaries were -59.94--43.67 and -9.00--6.04; those of the mainstream backwater affected zone of tributary were -77.85--50.75 and -11.06--7.33, which showed the same pattern as those of electrical conductivity and mass concentration of main anions and cations. This means that the mainstream affected the waterbody composition of tributaries through backwater as well as the chemical characterization of tributary water. The extent of mainstream backwater influence on tributaries was negatively correlated to the distance between the tributary estuary and Three Gorges Dam as well as tributary discharge. The hydrochemical characteristics of the mainstream backwater unaffected zone of the tributary were related to the tributary catchment properties. Tributaries with denser populations and higher proportions of cultivated land have poorer water quality. Mainstream backwater can pollute tributaries of better water quality and optimize those with poor water quality.
RESUMO
In order to evaluate the hydrological performance of permeable pavements in mitigating the surface runoff, four pilot-scale permeable pavement units were constructed in Shanghai and compared with impervious pavements. Three of the permeable facilities with waterproof liners included a pervious concrete pavement (facility â ), permeable interlocking concrete pavement using cement stabilized macadam as the base course (facility â ¡) and permeable interlocking concrete pavement using macadam as the base course (facility â ¢). The other two facilities were a conventional permeable interlocking concrete pavement without a liner (facility â £) and an impervious concrete pavement control (facility 0). V-notch flow meters, data loggers, and a rainfall meter were mounted to monitor the hydrological data. A double-ring infiltrometer was applied to evaluate the infiltration rate of the pavements. During the one-year experiment, the surface runoff and the underdrain discharge flow rate of the four pilot-scale facilities were continuously monitored in actual rainfall and the total volume reduction, peak flow reduction, and peak concentrating time of different facilities were investigated. The results showed that the surface steady infiltration rates of permeable interlocking concrete pavements were less than those of the pervious concrete, and the surface steady infiltration rates of the two types of surface layers decreased after one year of usage. The surface runoff reduction of the four facilities showed no significant differences. The water volume reduction rate of the three types of facilities was weak. The annual total volume reduction rates were 24.2%, 28.5%, and 28.4%, and the controlled rainfall amounts were 5.2 mm, 7.8 mm, and 7.8 mm. The peak flow reduction rate and the time to the peak flow of facility â were smaller than those of facility â ¡ and facility â ¢. The peak flow reduction rate and the time to the peak flow of the three facilities showed significant negative correlation with rainfall intensity.
