In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and down...In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns in uniform cross-section vertical tubes. It is found the effect is great. There exist great instabilities of two-phase flow in the neighboring areas of the SECS both downstream and upstream.展开更多
CO2 sorption and diffusion in coal are closely related to the occurrence of coal and gas outburst,geological sequestration of CO2 in coalbeds,and enhancing coalbed methane recovery by injecting CO2.Hence,it is signifi...CO2 sorption and diffusion in coal are closely related to the occurrence of coal and gas outburst,geological sequestration of CO2 in coalbeds,and enhancing coalbed methane recovery by injecting CO2.Hence,it is significant to investigate the sorption properties and diffusion models of CO2 in coal.Here we used a newly designed experimental apparatus at Peking University to investigate the sorption and diffusion properties of CO2 in natural coal samples from Dashucun Mine and Wutongzhuang Mine in Handan city,Hebei province,and Jinhuagong Mine in Datong city,Shanxi province,and obtained CO2 sorption isotherms and diffusivity models.The results indicate that,in a certain pressure range,CO2 sorption isotherms for the coal samples are consistent with the Langmuir model,which assumes that monolayer sorption occurs at the interface between coal matrix and CO2 molecules,and the sorption isotherms feature nonstandard hyperbolas in mathematics.At the same pressure and temperature,as the vitrinite content increases,coal adsorbs more CO2 molecules.The relation between the sorption capacity and the coal rank may be described as a "U-type" trend,and medium rank coal has the least sorption capacity.The bulk diffusivity of CO2 in coal is not constant;in the range of CO2 mass fraction greater than 1%,it increases roughly linearly with increasing mass fraction of CO2 adsorbed(or CO2 partial pressure) in coal.CO2 diffusivity in coal is approximately 10-4 to 10-2 mm2/s in magnitudes,and the diffusivity ranges in coal samples are 3×10-4 to 8×10-3 mm2/s from Dashucun Mine,2×10-4 to 4×10-3 mm2/s from Wutongzhuang Mine,and 2×10-4 to 4×10-3 mm2/s from Jinhuagong Mine.The results of the CO2 sorption and diffusion study can be applied to help predict and prevent coal and gas outburst as well as to evaluate the feasibility in geological sequestration of CO2 and to enhance coalbed methane recovery.展开更多
The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not...The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not equivalent to p53 loss,mutant p53 can acquire new functions to drive cell spreading and migration via different mechanisms.In our study,we found that mutant p53 significantly increased cell spreading and migration when comparing with p53-null cells.RNA-Seq analysis suggested that Rho GTPase activating protein 44(ARHGAP44) is a new target of mutant p53,which suppressed AKHGAP44 transcription.ARHGAP44 has GAP activity and catalyze GTP hydrolysis on Cdc42.Higher level of GTP-Cdc42 was correlated with increase expression of mutant p53 and reduced ARHGAP44.Importantly,wt-ARHGAP44 but not mutant ARHGAP44(R291A) suppressed mutant p53 mediated cell spreading and migration.Bioinformatics analysis indicated lower expression of ARHGAP44 in lung carcinoma compared with normal tissues,which was verified by RT-qPCR using specimens from patients.More interestingly,ARHGAP44 mRNA level was lower in tumors with mutant p53 than those with normal p53.Collectively,our results disclose a new mechanism by which mutant p53 stimulates cell spreading and migration.展开更多
基金the National Natural Science Foundation of China (No. 59236130).
文摘In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns in uniform cross-section vertical tubes. It is found the effect is great. There exist great instabilities of two-phase flow in the neighboring areas of the SECS both downstream and upstream.
基金supported by Peking University (985 Program by Chinese Ministry of Education)the National Natural Science Foundation of China (Grant No.40640420141)
文摘CO2 sorption and diffusion in coal are closely related to the occurrence of coal and gas outburst,geological sequestration of CO2 in coalbeds,and enhancing coalbed methane recovery by injecting CO2.Hence,it is significant to investigate the sorption properties and diffusion models of CO2 in coal.Here we used a newly designed experimental apparatus at Peking University to investigate the sorption and diffusion properties of CO2 in natural coal samples from Dashucun Mine and Wutongzhuang Mine in Handan city,Hebei province,and Jinhuagong Mine in Datong city,Shanxi province,and obtained CO2 sorption isotherms and diffusivity models.The results indicate that,in a certain pressure range,CO2 sorption isotherms for the coal samples are consistent with the Langmuir model,which assumes that monolayer sorption occurs at the interface between coal matrix and CO2 molecules,and the sorption isotherms feature nonstandard hyperbolas in mathematics.At the same pressure and temperature,as the vitrinite content increases,coal adsorbs more CO2 molecules.The relation between the sorption capacity and the coal rank may be described as a "U-type" trend,and medium rank coal has the least sorption capacity.The bulk diffusivity of CO2 in coal is not constant;in the range of CO2 mass fraction greater than 1%,it increases roughly linearly with increasing mass fraction of CO2 adsorbed(or CO2 partial pressure) in coal.CO2 diffusivity in coal is approximately 10-4 to 10-2 mm2/s in magnitudes,and the diffusivity ranges in coal samples are 3×10-4 to 8×10-3 mm2/s from Dashucun Mine,2×10-4 to 4×10-3 mm2/s from Wutongzhuang Mine,and 2×10-4 to 4×10-3 mm2/s from Jinhuagong Mine.The results of the CO2 sorption and diffusion study can be applied to help predict and prevent coal and gas outburst as well as to evaluate the feasibility in geological sequestration of CO2 and to enhance coalbed methane recovery.
基金supported by the National Program on Key Basic Research Project(2015CB901402)the National Natural Science Foundation of China(91629103,31670882, 81471066,81261120555,81672883,81401837,31071875,31200878, 31100946)+1 种基金the Science and Technology Commission of Shanghai Municipality(14430712100,11ZR1410000,16ZR1410000,16QA1401500)the Applied Basic Research Program of Science and Technology Department of Sichuan Province(2015JY0038)
文摘The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not equivalent to p53 loss,mutant p53 can acquire new functions to drive cell spreading and migration via different mechanisms.In our study,we found that mutant p53 significantly increased cell spreading and migration when comparing with p53-null cells.RNA-Seq analysis suggested that Rho GTPase activating protein 44(ARHGAP44) is a new target of mutant p53,which suppressed AKHGAP44 transcription.ARHGAP44 has GAP activity and catalyze GTP hydrolysis on Cdc42.Higher level of GTP-Cdc42 was correlated with increase expression of mutant p53 and reduced ARHGAP44.Importantly,wt-ARHGAP44 but not mutant ARHGAP44(R291A) suppressed mutant p53 mediated cell spreading and migration.Bioinformatics analysis indicated lower expression of ARHGAP44 in lung carcinoma compared with normal tissues,which was verified by RT-qPCR using specimens from patients.More interestingly,ARHGAP44 mRNA level was lower in tumors with mutant p53 than those with normal p53.Collectively,our results disclose a new mechanism by which mutant p53 stimulates cell spreading and migration.
