Cemented paste backfill(CPB)technology is a green mining method used to control underground goaves and tailings ponds.The curing process of CPB in the stope is the product of a thermo-hydro-mechanical-chemical multi-f...Cemented paste backfill(CPB)technology is a green mining method used to control underground goaves and tailings ponds.The curing process of CPB in the stope is the product of a thermo-hydro-mechanical-chemical multi-field performance interaction.At present,research on the multi-field performance of CPB mainly includes indoor similar simulation experiments,in-situ multi-field performance monitoring experiments,multi-field performance coupling model construction of CPB,and numerical simulation of the multi-field performance of CPB.Because it is hard to study the in-situ multi-field performance of CPB in the real stope,most current research on in-situ multi-field performance adopts the numerical simulation method.By simulating the conditions of CPB in the real stope(e.g.,maintenance environment,stope geometry,drainage conditions,and barricade and backfilling rates),the multi-field performance of CPB is further studied.This paper summarizes the mathematical models employed in the numerical simulation and lists the engineering application cases of numerical simulation in the in-situ multi-field performance of CPB.Finally,it proposes that the multi-field performance of CPB needs to strengthen the theoretical study of multi-field performance,form the strength design criterion based on the multi-field performance of CPB,perform a full-range numerical simulation of the multi-field performance of CPB,develop a pre-warning technology for the CPB safety of CPB,develop automatic and wireless sensors for the multi-field performance monitoring of CPB,and realize the application and popularization of CPB monitoring technology.展开更多
In underground coal mines, fibre reinforced polymer(FRP) bolt is ideal for mined rib reinforcements as it can prevent gas explosions caused by shearer frictional spark. With increasing mining depth, small diameter FRP...In underground coal mines, fibre reinforced polymer(FRP) bolt is ideal for mined rib reinforcements as it can prevent gas explosions caused by shearer frictional spark. With increasing mining depth, small diameter FRP bolts used in shallow underground mining cannot fulfil the rib support requirements. Under the engineering background of deep underground shortwall mining in Wudong coal mine, this paper systematically studies Φ27 mm FRP bolt support for large deformation coal rib. Specimens with a fan-shaped cross-section were used to enable the tensile testing of the bolt rod, the measured average tensile strength of the studied FRP bolt was(486.1 ± 9.6) MPa with a maximum elongation of 5.7%±0.6%.The shear strength of the bolt was measured as approximately 258 MPa using a self-made double shear testing apparatus. Based on the equivalent radial stiffness principle, a laboratory short encapsulation pullout test(SEPT) method for rib bolting has been developed undertaken consideration of the mechanical properties of the coal seam. Results showed that the average peak anchorage forces of the Φ27 mm FRP bolt and Φ20 mm steel rebar bolt were 108.4 and 66.4 k N, respectively, which were agreed with the theoretical calculations and field measurements. Based on theoretical analysis of the loading states of the bolt under site conditions, bolting method of full-length resin grouting was adopted to offset the weaknesses of the FRP bolt. Numerical method was employed to compare the bolting effect using Φ27 mm FRP bolts and steel rebar bolts. Large diameter FRP bolting was determined as the optimum rib support scheme to increase the productivity of the coal mine and to enhance the ground control capability for+425 level mining roadways. This study provides the laboratory testing design and theoretical prediction of large diameter FRP bolts used for rib support in large deformation roadways.展开更多
Objective Fatal familial insomnia(FFI) is an autosomal dominant prion disease characterized clinically by inattention,sleep loss,dysautonomia,and motor signs.This study is aimed to investigate clinical and familial ch...Objective Fatal familial insomnia(FFI) is an autosomal dominant prion disease characterized clinically by inattention,sleep loss,dysautonomia,and motor signs.This study is aimed to investigate clinical and familial characteristics of ten Chinese Patients with FFI.Methods We identified ten FFI cases from the surveillance network for Creutafeldt-Jakob disease(CJD) in China.Final diagnosis of FFI cases was made in accordance with the WHO criteria for CJD.The main clinical features and family histories of these ten FFI cases were analyzed.Results The median age of ten cases at onset was 38 years(from 19 to 55).The foremost symptoms seemed to be various,including sleep disturbances,vision disorder,dizziness and anorexia.Sleep disturbances appeared in all cases and lasted in the whole clinical courses.Progressive sympathetic symptoms,memory loss,movement disturbances,myoclonus and hypertension were also frequently observed.The median duration of the disease was 9.5 months.EEG and MRI did not figure out special abnormality.14-3-3 protein in CSF was positive in five out of eight tested patients.Clear family histories were identified in 8 patients.Conclusion The data from our study confirm that the Chinese FFI cases have similar clinical characteristics as that of the Caucasian cases.Compared with other genetic CJD associated mutations,the genetic frequencies of D178N in PRNP are apparently high among the Chinese cases.展开更多
Objective To break immune tolerance to prion (PrP) proteins using DNA vaccines.Methods Four different human prion DNA vaccine candidates were constructed based on the pcDNA3.1 vector:PrP‐WT expressing wild‐type PrP,...Objective To break immune tolerance to prion (PrP) proteins using DNA vaccines.Methods Four different human prion DNA vaccine candidates were constructed based on the pcDNA3.1 vector:PrP‐WT expressing wild‐type PrP,Ubiq‐PrP expressing PrP fused to ubiquitin,PrP‐LII expressing PrP fused to the lysosomal integral membrane protein type II lysosome‐targeting signal,and PrP‐ER expressing PrP locating the ER.Using a prime‐boost strategy,three‐doses of DNA vaccine were injected intramuscularly into Balb/c mice,followed by two doses of PrP protein.Two weeks after the last immunization,sera and spleens were collected and PrP‐specific humoral and cellular immune responses evaluated by ELISA and ELISPOT tests.Results Higher levels of serum PrP antibodies were detected in mice vaccinated using the strategy of DNA priming followed by protein boosting.Of these,WT‐PrP,Ubiq‐PrP,and PrP‐LII induced significantly higher humoral responses.ELISPOT tests showed markedly increased numbers of IFN‐γ‐secreting T cells in mice vaccinated using the strategy of DNA priming followed by protein boosting after stimulation with recombinant PrP23‐90 and PrP23‐231.PrP‐ER inducedthe strongest T‐cell response.Conclusion Prion vaccines can break tolerance to PrP proteins and induce PrP‐specific humoral and cellular immune responses.展开更多
The COVID-19 pandemic has affected 220 countries,areas,and territories worldwide,with more than 65 million confirmed cases and 1.5 million deaths[1].By the beginning of May,2020,only a few countries,such as China,Sout...The COVID-19 pandemic has affected 220 countries,areas,and territories worldwide,with more than 65 million confirmed cases and 1.5 million deaths[1].By the beginning of May,2020,only a few countries,such as China,South Korea,Australia,and New Zealand,seemed to be close to the epidemic’s late stage with a few daily reported new cases[1].展开更多
基金financially supported by the National Natural Science Foundation of China(No.52130404)the State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining&Technology,Beijing(No.SKLGDUEK2127)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-19-002C2Z,FRF-IDRY-20-031)and the Fundamental Research Funds for the Central Universities and the Youth Teacher International Exchange&Growth Program(No.QNXM20220002)。
文摘Cemented paste backfill(CPB)technology is a green mining method used to control underground goaves and tailings ponds.The curing process of CPB in the stope is the product of a thermo-hydro-mechanical-chemical multi-field performance interaction.At present,research on the multi-field performance of CPB mainly includes indoor similar simulation experiments,in-situ multi-field performance monitoring experiments,multi-field performance coupling model construction of CPB,and numerical simulation of the multi-field performance of CPB.Because it is hard to study the in-situ multi-field performance of CPB in the real stope,most current research on in-situ multi-field performance adopts the numerical simulation method.By simulating the conditions of CPB in the real stope(e.g.,maintenance environment,stope geometry,drainage conditions,and barricade and backfilling rates),the multi-field performance of CPB is further studied.This paper summarizes the mathematical models employed in the numerical simulation and lists the engineering application cases of numerical simulation in the in-situ multi-field performance of CPB.Finally,it proposes that the multi-field performance of CPB needs to strengthen the theoretical study of multi-field performance,form the strength design criterion based on the multi-field performance of CPB,perform a full-range numerical simulation of the multi-field performance of CPB,develop a pre-warning technology for the CPB safety of CPB,develop automatic and wireless sensors for the multi-field performance monitoring of CPB,and realize the application and popularization of CPB monitoring technology.
基金The work presented in this paper was financially jointly supported by General Project of the National Natural Science Foundation of China(No.52074145)Liaoning Revitalization Talents Program(No.XLYC2002110).
文摘In underground coal mines, fibre reinforced polymer(FRP) bolt is ideal for mined rib reinforcements as it can prevent gas explosions caused by shearer frictional spark. With increasing mining depth, small diameter FRP bolts used in shallow underground mining cannot fulfil the rib support requirements. Under the engineering background of deep underground shortwall mining in Wudong coal mine, this paper systematically studies Φ27 mm FRP bolt support for large deformation coal rib. Specimens with a fan-shaped cross-section were used to enable the tensile testing of the bolt rod, the measured average tensile strength of the studied FRP bolt was(486.1 ± 9.6) MPa with a maximum elongation of 5.7%±0.6%.The shear strength of the bolt was measured as approximately 258 MPa using a self-made double shear testing apparatus. Based on the equivalent radial stiffness principle, a laboratory short encapsulation pullout test(SEPT) method for rib bolting has been developed undertaken consideration of the mechanical properties of the coal seam. Results showed that the average peak anchorage forces of the Φ27 mm FRP bolt and Φ20 mm steel rebar bolt were 108.4 and 66.4 k N, respectively, which were agreed with the theoretical calculations and field measurements. Based on theoretical analysis of the loading states of the bolt under site conditions, bolting method of full-length resin grouting was adopted to offset the weaknesses of the FRP bolt. Numerical method was employed to compare the bolting effect using Φ27 mm FRP bolts and steel rebar bolts. Large diameter FRP bolting was determined as the optimum rib support scheme to increase the productivity of the coal mine and to enhance the ground control capability for+425 level mining roadways. This study provides the laboratory testing design and theoretical prediction of large diameter FRP bolts used for rib support in large deformation roadways.
基金supported by China Mega-Project for Infectious Disease(2009ZX10004-101,2008ZX)SKLID Development Grant(2008SKLID102,2011SKLID211)+3 种基金National Basic Research Program of China(973 Program)(2007CB310505)sponsored by the Young Scholar Scientific Research Foundation of China CDC(2012A102)Chinese National Natural Science Foundation Grants 30771914 and 30800975 Institution Technique R&D Grant(2008EG150300)
文摘Objective Fatal familial insomnia(FFI) is an autosomal dominant prion disease characterized clinically by inattention,sleep loss,dysautonomia,and motor signs.This study is aimed to investigate clinical and familial characteristics of ten Chinese Patients with FFI.Methods We identified ten FFI cases from the surveillance network for Creutafeldt-Jakob disease(CJD) in China.Final diagnosis of FFI cases was made in accordance with the WHO criteria for CJD.The main clinical features and family histories of these ten FFI cases were analyzed.Results The median age of ten cases at onset was 38 years(from 19 to 55).The foremost symptoms seemed to be various,including sleep disturbances,vision disorder,dizziness and anorexia.Sleep disturbances appeared in all cases and lasted in the whole clinical courses.Progressive sympathetic symptoms,memory loss,movement disturbances,myoclonus and hypertension were also frequently observed.The median duration of the disease was 9.5 months.EEG and MRI did not figure out special abnormality.14-3-3 protein in CSF was positive in five out of eight tested patients.Clear family histories were identified in 8 patients.Conclusion The data from our study confirm that the Chinese FFI cases have similar clinical characteristics as that of the Caucasian cases.Compared with other genetic CJD associated mutations,the genetic frequencies of D178N in PRNP are apparently high among the Chinese cases.
基金supported by Chinese National Natural Science Foundation Grants 30771914 and 30800975Institution Technique R&D Grant (2008EG150300)+2 种基金National Basic Research Program of China (973 Program) (2007CB310505)China Mega-Project for Infectious Disease (2009ZX10004‐101, 2008ZX10004‐001, and 2008ZX10004‐002)the SKLID Development Grant (2008SKLID102 and 2008SKLID202)
文摘Objective To break immune tolerance to prion (PrP) proteins using DNA vaccines.Methods Four different human prion DNA vaccine candidates were constructed based on the pcDNA3.1 vector:PrP‐WT expressing wild‐type PrP,Ubiq‐PrP expressing PrP fused to ubiquitin,PrP‐LII expressing PrP fused to the lysosomal integral membrane protein type II lysosome‐targeting signal,and PrP‐ER expressing PrP locating the ER.Using a prime‐boost strategy,three‐doses of DNA vaccine were injected intramuscularly into Balb/c mice,followed by two doses of PrP protein.Two weeks after the last immunization,sera and spleens were collected and PrP‐specific humoral and cellular immune responses evaluated by ELISA and ELISPOT tests.Results Higher levels of serum PrP antibodies were detected in mice vaccinated using the strategy of DNA priming followed by protein boosting.Of these,WT‐PrP,Ubiq‐PrP,and PrP‐LII induced significantly higher humoral responses.ELISPOT tests showed markedly increased numbers of IFN‐γ‐secreting T cells in mice vaccinated using the strategy of DNA priming followed by protein boosting after stimulation with recombinant PrP23‐90 and PrP23‐231.PrP‐ER inducedthe strongest T‐cell response.Conclusion Prion vaccines can break tolerance to PrP proteins and induce PrP‐specific humoral and cellular immune responses.
基金supported by National Key R&D Program of China[2018YFC1200305]。
文摘The COVID-19 pandemic has affected 220 countries,areas,and territories worldwide,with more than 65 million confirmed cases and 1.5 million deaths[1].By the beginning of May,2020,only a few countries,such as China,South Korea,Australia,and New Zealand,seemed to be close to the epidemic’s late stage with a few daily reported new cases[1].
