Melatonin attenuates hepatic ischemia-reperfusion injury in rats by inhibiting NF-κB signaling pathway

Background:The sterile inflammatory response is one of the key mechanisms leading to hepatic ischemia-reperfusion injury.Melatonin has been shown to prevent organ injuries,but its roles in the inflammatory response after hepatic ischemia-reperfusion injury have not been fully explored,especially in late ischemia-reperfusion injury.The present study aimed to investigate the roles and possible mechanisms of melatonin in the inflammatory response after hepatic ischemia-reperfusion injury.Methods:Sixty Sprague-Dawley rats were randomly divided into a sham group,ischemia-reperfusion injury group(I/R group),and melatonin-treated group(M+I/R group).The rats in the I/R group were subjected to 70%hepatic ischemia for 45 min,followed by 5 or 24 h of reperfusion.The rats in the M+I/R group were injected with melatonin(10 mg/kg,intravenous injection)15 min prior to ischemia and immediately before reperfusion.Serum and samples of ischemic liver lobes were harvested for future analysis,and the 7-day survival rate was assessed after hepatic ischemia-reperfusion surgery.Results:In comparison with the I/R group,the M+I/R group showed markedly decreased expression levels of inflammatory cytokines(IL-6 and TNF-α)and numbers of apoptotic hepatocytes(P<0.05).Immunoblotting showed that the expression levels of IL-6,p-NF-κBp65/t-NF-κBp65 and p-IκB-α/t-IκB-αin the M+I/R group were significantly lower than those in the I/R group,and immunofluorescence staining showed that the expression level of p-NF-κBp65 in the M+I/R group was lower than that in the I/R group(P<0.05).The 7-day survival rates were 20%in the I/R group and 50%in the M+I/R group(P<0.05).Conclusions:Melatonin downregulated the activity of the NF-κB signaling pathway in the early and late stages of hepatic ischemia-reperfusion injury,alleviated the inflammatory response,protected the liver from ischemia-reperfusion injury,and increased the survival rate.

Prediction verification of solar cycles 18–24 and a preliminary prediction of the maximum amplitude of solar cycle 25 based on the Precursor Method

Predictions of the strength of solar cycles are important and are necessary for planning long-term missions.A new solar cycle 25 is coming soon,and the amplitude is needed for space weather operators.Some predictions have been made using different methods and the values are drastically different.However,since 2015 July 1,the original sunspot number data have been entirely replaced by the Version 2.0 data series,and the sunspot number values have changed greatly.In this paper,using Version 2 smoothed sunspot numbers and aa indices,we verify the predictions for cycles 18-24 based on Ohl’s Precursor Method.Then a similar-cycles method is used to evaluate the aa minimum of 9.7(±1.1)near the start of cycle 25 and based on the linear regression relationship between sunspot maxima and aa minima,our predicted Version 2maximum sunspot number for cycle 25 is 121.5(±32.9).

Numerical simulation of the impact of polymer rheology on polymer injectivity using a multilevel local grid refinement method

Polymer injectivity is an important factor for evaluating the project economics of chemical flood,which is highly related to the polymer viscosity.Because the flow rate varies rapidly near injectors and significantly changes the polymer viscosity due to the non-Newtonian rheological behavior,the polymer viscosity near the wellbore is difficult to estimate accurately with the practical gridblock size in reservoir simulation.To reduce the impact of polymer rheology upon chemical EOR simulations,we used an efficient multilevel local grid refinement（LGR）method that provides a higher resolution of the flows in the near-wellbore region.An efficient numerical scheme was proposed to accurately solve the pressure equation and concentration equations on the multilevel grid for both homogeneous and heterogeneous reservoir cases.The block list and connections of the multilevel grid are generated via an efficient and extensible algorithm.Field case simulation results indicate that the proposed LGR is consistent with the analytical injectivity model and achieves the closest results to the full grid refinement,which considerably improves the accuracy of solutions compared with the original grid.In addition,the method was validated by comparing it with the LGR module of CMG_STARS.Besides polymer injectivity calculations,the LGR method is applicable for other problems in need of near-wellbore treatment,such as fractures near wells.

Thermodynamic Analysis and Experimental Study on Reaction of CO_2 Gas with Hot Metal

The reaction of CO2 gas with hot metal was investigated based on the thermodynamic analysis and experi- mental results. It shows that both silicon and carbon in hot metal can be oxidized by CO2 gas in the temperature range of 1300-1 500 ℃. When using graphite crucible, temperature has little influence on final mass percent of car bon w[c] because of the carburization effect. Decarburization degree rises significantly with increasing gas injection rate and w[c] can be reduced to 3.2% at most when using MgO crucible. I.ower temperature or higher gas injection rate is propitious to promote desilication reaction, but only 5%- 10% of desilication ratio could be obtained in 20 rain. The final mass percent of silicon W[si] when using MgO crucible is lower than that when using graphite crucible. Ex- perimental results also demonstrate that CO2 injection has no effect on the concentration of manganese, sulfur and phosphorus in hot metal. In view of the weak oxidation ability and temperature drop of hot metal, CO2 gas is sugges- ted to be used as carrier gas in desilication process rather than oxidizing agent.