Invasion of drilling fluid into natural gas hydrate deposits during drilling might damage the reservoir,induce hydrate dissociation and then cause wellbore instability and distortion of the data from well logging. Add...Invasion of drilling fluid into natural gas hydrate deposits during drilling might damage the reservoir,induce hydrate dissociation and then cause wellbore instability and distortion of the data from well logging. Adding nanoparticles into drilling fluid is an effective method in reducing the invasion of drilling fluid and enhancing borehole stability. However, the addition of nanoparticles might also introduce hydrate formation risk in borehole because they can act as the "seeds" for hydrate nucleation. This paper presents an experimental study of the effect of hydrophilic silica nanoparticle on gas hydrate formation in a dynamic methane/liquid-water system. In the experiment, the ultrapure water with and without1.0 wt%–6.0 wt% concentrations of silica nanoparticles, grain sizes of 20 and 50 nm, were pressurized by methane gas under varied conditions of temperature and pressure. The induction time, the gas consumption, and the average rate of gas consumption in the system were measured and compared to those in ultrapure water. The results show that a concentration of 4.0 wt% hydrophilic SiO_2 particles with a grain size of 50 nm has a relatively strong inhibition effect on hydrate formation when the initial experimental condition is 5.0 °C and 5.0 MPa. Compared to ultrapure water, the hydrophilic nano-SiO_2 fluid increases the induction time for hydrate formation by 194% and decreases the amount and average rate of hydrate formation by 10% and 17%, respectively. This inhibition effect may be attributed to the hydrophilicity,amount and aggregation of silica nanoparticle according to the results of water activity and zeta potential measurements. Our work also elucidates hydrophilic, instead of hydrophobic, nanoparticles can be added to the drilling fluid to maintain wellbore stability and to protect the hydrate reservoir from drilling mud damage, because they exhibit certain degree of hydrate inhibition which can reduce the risk of hydrate reformation and aggregation during gas hydrate or deep water drilling if their concentration can be controlled properly.展开更多
Heat waves induced by climate warming have become common in food-producing regions worldwide,frequently coinciding with high temperature(HT)-sensitive stages of many crops and thus threatening global food security.Und...Heat waves induced by climate warming have become common in food-producing regions worldwide,frequently coinciding with high temperature(HT)-sensitive stages of many crops and thus threatening global food security.Understanding the HT sensitivity of reproductive organs is currently of great interest for increasing seed set.The responses of seed set to HT involve multiple processes in both male and female reproductive organs,but we currently lack an integrated and systematic summary of these responses for the world’s three leading food crops(rice,wheat,and maize).In the present work,we define the critical high temperature thresholds for seed set in rice(37.2℃±0.2℃),wheat(27.3℃±0.5℃),and maize(37.9℃±0.4℃)during flowering.We assess the HT sensitivity of these three cereals from the microspore stage to the lag period,including effects of HT on flowering dynamics,floret growth and development,pollination,and fertilization.Our review synthesizes existing knowledge about the effects of HT stress on spikelet opening,anther dehiscence,pollen shedding number,pollen viability,pistil and stigma function,pollen germination on the stigma,and pollen tube elongation.HT-induced spikelet closure and arrest of pollen tube elongation have a catastrophic effect on pollination and fertilization in maize.Rice benefits from pollination under HT stress owing to bottom anther dehiscence and cleistogamy.Cleistogamy and secondary spikelet opening increase the probability of pollination success in wheat under HT stress.However,cereal crops themselves also have protective measures under HT stress.Lower canopy/tissue temperatures compared with air temperatures indicate that cereal crops,especially rice,can partly protect themselves from heat damage.In maize,husk leaves reduce inner ear temperature by about 5℃compared with outer ear temperature,thereby protecting the later phases of pollen tube growth and fertilization processes.These findings have important implications for accurate modeling,optimized crop management,and breeding of new varieties to cope with HT stress in the most important staple crops.展开更多
Tryptophan 2,3-dioxygnease 2(TDO2) is specific for metabolizing tryptophan to kynurenine(KYN),which plays a critical role in mediating immune escape of cancer.Although accumulating evidence demonstrates that TDO2 over...Tryptophan 2,3-dioxygnease 2(TDO2) is specific for metabolizing tryptophan to kynurenine(KYN),which plays a critical role in mediating immune escape of cancer.Although accumulating evidence demonstrates that TDO2 overexpression is implicated in the development and progression of multiple cancers,its tumor-promoting role in esophageal squamous cell carcinoma(ESCC) remains unclear.Here,we observed that TDO2 was overexpressed in ESCC tis sues and correlated significantly with lymph node metastasis,advanced clinical stage,and unfavorable prognosis.Functional experiments showed that TDO2 promoted tumor cell proliferation,migration,and colony formation,which could be prevented by inhibition of TDO2 and aryl hydrocarb on receptor(AHR).Further experimentation demonstrated that TDO2 could promote the tumor growth of KYSE150 tumor-bearing model,tumor burden of C57 BL/6 mice with ESCC induced by 4-NQO,enhance the expression of phosphorylated AKT,with subsequent pho sphorylation of GSK3β,and polarization of M2 macrophages by upregulating interleukin-8(IL-8) to accelerate tumor progression in the tumor microenvironment(TME).Collectively,our results discovered that TDO2 could upregulate IL-8 through AKT/GSK3β to direct the polarization of M2 macrophages in ESCC,and suggested that TDO2 could represent as an attractive therapeutic target and prognostic marker to ESCC.展开更多
基金supported by National Youth Top-notch Talent Support Programthe National Natural Science Foundationof China(41672367,51704266)+2 种基金China Geological Survey Project(DD20160216)Qingdao National Laboratory for Marine Science and Technology Open Fund(QNLM2016ORP0203)Experimental Apparatus Improvement Program of CUG(SJ-201613)
文摘Invasion of drilling fluid into natural gas hydrate deposits during drilling might damage the reservoir,induce hydrate dissociation and then cause wellbore instability and distortion of the data from well logging. Adding nanoparticles into drilling fluid is an effective method in reducing the invasion of drilling fluid and enhancing borehole stability. However, the addition of nanoparticles might also introduce hydrate formation risk in borehole because they can act as the "seeds" for hydrate nucleation. This paper presents an experimental study of the effect of hydrophilic silica nanoparticle on gas hydrate formation in a dynamic methane/liquid-water system. In the experiment, the ultrapure water with and without1.0 wt%–6.0 wt% concentrations of silica nanoparticles, grain sizes of 20 and 50 nm, were pressurized by methane gas under varied conditions of temperature and pressure. The induction time, the gas consumption, and the average rate of gas consumption in the system were measured and compared to those in ultrapure water. The results show that a concentration of 4.0 wt% hydrophilic SiO_2 particles with a grain size of 50 nm has a relatively strong inhibition effect on hydrate formation when the initial experimental condition is 5.0 °C and 5.0 MPa. Compared to ultrapure water, the hydrophilic nano-SiO_2 fluid increases the induction time for hydrate formation by 194% and decreases the amount and average rate of hydrate formation by 10% and 17%, respectively. This inhibition effect may be attributed to the hydrophilicity,amount and aggregation of silica nanoparticle according to the results of water activity and zeta potential measurements. Our work also elucidates hydrophilic, instead of hydrophobic, nanoparticles can be added to the drilling fluid to maintain wellbore stability and to protect the hydrate reservoir from drilling mud damage, because they exhibit certain degree of hydrate inhibition which can reduce the risk of hydrate reformation and aggregation during gas hydrate or deep water drilling if their concentration can be controlled properly.
基金supported by the National Science Foundation of China(32272214)the 2115 Talent Development Program of China Agricultural University,and the General Project of Chongqing Natural Science Foundation(cstc2021jcyj-msxmX0747).
文摘Heat waves induced by climate warming have become common in food-producing regions worldwide,frequently coinciding with high temperature(HT)-sensitive stages of many crops and thus threatening global food security.Understanding the HT sensitivity of reproductive organs is currently of great interest for increasing seed set.The responses of seed set to HT involve multiple processes in both male and female reproductive organs,but we currently lack an integrated and systematic summary of these responses for the world’s three leading food crops(rice,wheat,and maize).In the present work,we define the critical high temperature thresholds for seed set in rice(37.2℃±0.2℃),wheat(27.3℃±0.5℃),and maize(37.9℃±0.4℃)during flowering.We assess the HT sensitivity of these three cereals from the microspore stage to the lag period,including effects of HT on flowering dynamics,floret growth and development,pollination,and fertilization.Our review synthesizes existing knowledge about the effects of HT stress on spikelet opening,anther dehiscence,pollen shedding number,pollen viability,pistil and stigma function,pollen germination on the stigma,and pollen tube elongation.HT-induced spikelet closure and arrest of pollen tube elongation have a catastrophic effect on pollination and fertilization in maize.Rice benefits from pollination under HT stress owing to bottom anther dehiscence and cleistogamy.Cleistogamy and secondary spikelet opening increase the probability of pollination success in wheat under HT stress.However,cereal crops themselves also have protective measures under HT stress.Lower canopy/tissue temperatures compared with air temperatures indicate that cereal crops,especially rice,can partly protect themselves from heat damage.In maize,husk leaves reduce inner ear temperature by about 5℃compared with outer ear temperature,thereby protecting the later phases of pollen tube growth and fertilization processes.These findings have important implications for accurate modeling,optimized crop management,and breeding of new varieties to cope with HT stress in the most important staple crops.
基金supported by the National Natural Science Foundation of China(Nos.U1604286,81822043,and 81901687)Shenzhen Science and Technology Program(3000531,China)the Key Incubation Fund of SYSU(19ykzd29,China)
文摘Tryptophan 2,3-dioxygnease 2(TDO2) is specific for metabolizing tryptophan to kynurenine(KYN),which plays a critical role in mediating immune escape of cancer.Although accumulating evidence demonstrates that TDO2 overexpression is implicated in the development and progression of multiple cancers,its tumor-promoting role in esophageal squamous cell carcinoma(ESCC) remains unclear.Here,we observed that TDO2 was overexpressed in ESCC tis sues and correlated significantly with lymph node metastasis,advanced clinical stage,and unfavorable prognosis.Functional experiments showed that TDO2 promoted tumor cell proliferation,migration,and colony formation,which could be prevented by inhibition of TDO2 and aryl hydrocarb on receptor(AHR).Further experimentation demonstrated that TDO2 could promote the tumor growth of KYSE150 tumor-bearing model,tumor burden of C57 BL/6 mice with ESCC induced by 4-NQO,enhance the expression of phosphorylated AKT,with subsequent pho sphorylation of GSK3β,and polarization of M2 macrophages by upregulating interleukin-8(IL-8) to accelerate tumor progression in the tumor microenvironment(TME).Collectively,our results discovered that TDO2 could upregulate IL-8 through AKT/GSK3β to direct the polarization of M2 macrophages in ESCC,and suggested that TDO2 could represent as an attractive therapeutic target and prognostic marker to ESCC.