In order to investigate the problem of long-term strength retrogression in oil well cement systems exposed to high pressure and high temperature(HPHT)curing conditions,various influencing factors,including cement sour...In order to investigate the problem of long-term strength retrogression in oil well cement systems exposed to high pressure and high temperature(HPHT)curing conditions,various influencing factors,including cement sources,particle sizes of silica flour,and additions of silica fume,alumina,colloidal iron oxide and nano-graphene,were investigated.To simulate the environment of cementing geothermal wells and deep wells,cement slurries were directly cured at 50 MPa and 200?C.Mineral compositions(as determined by X-ray diffraction Rietveld refinement),water permeability,compressive strength and Young’s modulus were used to evaluate the qualities of the set cement.Short-term curing(2e30 d)test results indicated that the adoption of 6 m m ultrafine crystalline silica played the most important role in stabilizing the mechanical properties of oil well cement systems,while the addition of silica fume had a detrimental effect on strength stability.Long-term curing(2e180 d)test results indicated that nano-graphene could stabilize the Young’s modulus of oil well cement systems.However,none of the ad-mixtures studied here can completely prevent the strength retrogression phenomenon due to their inability to stop the conversion of amorphous to crystalline phases.展开更多
BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an essential therapeutic tool for biliary and pancreatic diseases.Frail and elderly patients,especially those aged≥90 years are generally considered a...BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an essential therapeutic tool for biliary and pancreatic diseases.Frail and elderly patients,especially those aged≥90 years are generally considered a higher-risk population for ERCP-related complications.AIM To investigate outcomes of ERCP in the Non-agenarian population(≥90 years)concerning Frailty.METHODS This is a cohort study using the 2018-2020 National Readmission Database.Patients aged≥90 were identified who underwent ERCP,using the international classification of diseases-10 code with clinical modification.Johns Hopkins’s adjusted clinical groups frailty indicator was used to classify patients as frail and non-frail.The primary outcome was mortality,and the secondary outcomes were morbidity and the 30 d readmission rate related to ERCP.We used univariate and multivariate regression models for analysis.RESULTS A total of 9448 patients were admitted for any indications of ERCP.Frail and non-frail patients were 3445(36.46%)and 6003(63.53%)respectively.Indications for ERCP were Choledocholithiasis(74.84%),Biliary pancreatitis(9.19%),Pancreatico-biliary cancer(7.6%),Biliary stricture(4.84%),and Cholangitis(1.51%).Mortality rates were higher in frail group[adjusted odds ratio(aOR)=1.68,P=0.02].The Intra-procedural complications were insigni-ficant between the two groups which included bleeding(aOR=0.72,P=0.67),accidental punctures/lacerations(aOR=0.77,P=0.5),and mechanical ventilation rates(aOR=1.19,P=0.6).Post-ERCP complication rate was similar for bleeding(aOR=0.72,P=0.41)and post-ERCP pancreatitis(aOR=1.4,P=0.44).Frail patients had a longer length of stay(6.7 d vs 5.5 d)and higher mean total charges of hospitalization($78807 vs$71392)compared to controls(P<0.001).The 30 d all-cause readmission rates between frail and non-frail patients were similar(P=0.96).CONCLUSION There was a significantly higher mortality risk and healthcare burden amongst nonagenarian frail patients undergoing ERCP compared to non-frail.Larger studies are warrant展开更多
The formation of many hydrothermal gold deposits is closely related to iron-rich rocks. The host rocks of the Madiyi Formation of the Mid-to Late Neoproterozoic Banxi Group for the Woxi Au(-Sb-W) deposit, which is loc...The formation of many hydrothermal gold deposits is closely related to iron-rich rocks. The host rocks of the Madiyi Formation of the Mid-to Late Neoproterozoic Banxi Group for the Woxi Au(-Sb-W) deposit, which is located in western Hunan Province of the western Jiangnan Orogen, South China, is rich in hematite, which provides a good example for studying the relationship between the formation of gold deposit and iron-rich rocks. Field investigation and petrographic observation on the unaltered, weakly altered and strongly altered rocks demonstrate that the bleaching is caused by a combination of carbonatization, sulfidation and sericitization. Mass balance calculation suggests that, during decolourization there is no change in TFe_(2)O_(3), while FeO is gained and Fe_(2)O_(3)is lost. Geochemical modeling found that Au was mainly present as AuHS(aq) and Au(HS)-2, and that the water-rock interactions decreased the sulfur fugacity which destroyed the stability of such aqueous complexes. Combined with the locally occurred native gold in quartz veins, it is concluded that the major gold precipitation mechanisms are sulfidation and fluid boiling. Based on previous geochronological and geochemical research further gold mineralization is proposed to be generated by deep sourced magmatic or metamorphic fluid migrated upward along the Woxi fault, and the iron-rich Madiyi Formation is the idea chemical trap for gold deposition. The decrease of sulfur contents caused by fluid-rock interactions and fluid boiling are the major mechanisms for gold mineralization.展开更多
In this work,we investigate a generalization of the classical capacitated arc routing problem,called the Multi-depot Capacitated Arc Routing Problem(MCARP).We give exact and approximation algorithms for different vari...In this work,we investigate a generalization of the classical capacitated arc routing problem,called the Multi-depot Capacitated Arc Routing Problem(MCARP).We give exact and approximation algorithms for different variants of the MCARP.First,we obtain the first constant-ratio approximation algorithms for the MCARP and its nonfixed destination version.Second,for the multi-depot rural postman problem,i.e.,a special case of the MCARP where the vehicles have infinite capacity,we develop a(2-1/2k+1)-approximation algorithm(k denotes the number of depots).Third,we show the polynomial solvability of the equal-demand MCARP on a line and devise a 2-approximation algorithm for the multi-depot capacitated vehicle routing problem on a line.Lastly,we conduct extensive numerical experiments on the algorithms for the multi-depot rural postman problem to show their effectiveness.展开更多
The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallo...The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallogeny of the deposit have included its timing,the ore-controlling structures and sedimentary host rocks and their implications for mineral exploration.However,the deep nappe structural style of Taqian-Fuchun metallogenic belt that hosts the W deposit,and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined,which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit.Modern 3 D geological modeling is an important tool for the exploration of concealed orebodies,especially in brownfield environments.There are obvious density contrast and weak magnetic contrast in the ore-controlling strata and granite at the periphery of the deposit,which lays a physical foundation for solving the 3 D spatial problems of the ore-controlling geological body in the deep part of the study area through gravity and magnetic modeling.Gravity data(1:50000)and aeromagnetic data(1:50000)from the latest geophysical surveys of 2016-2018 have been used,firstly,to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion.Then,on the basis of the analysis of the relationship between physical properties and lithology,under the constraints of surface geology and borehole data,human-computer interactive gravity and magnetic inversion for 18 cross-sections were completed.Finally,the 3 D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections,and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained,initially realizing―transparency‖for ore-controlling bodies.According the analysis of the geophysical,geochemical,and geological characteristics of the Zhuxi tungsten deposit,we di展开更多
At the end of 2019,the novel coronavirus infection outbroke in Wuhan,Hubei Province.On Feb.2,2020,Wuhan,as the worst-hit region,began to build“shelter hospital”rapidly to treat patients with mild ilness.The shelter ...At the end of 2019,the novel coronavirus infection outbroke in Wuhan,Hubei Province.On Feb.2,2020,Wuhan,as the worst-hit region,began to build“shelter hospital”rapidly to treat patients with mild ilness.The shelter hospital has multiple functions such as emergency treatment,surgical treatment and clinical test,which can adapt to emergency medical rescue tasks.Based on the characteristics that shelter hospital only treats patients with mild ilness,tests of shelter laboratory,including coronavirus nucleic acid detection,IgM/IgG antibody serology detection,monitoring and auxiliary diagnosis and/or a required blood routine,urine routine,C-reactive protein,calcitonin original,biochemical indicators(liver enzymes,myocardial enzymes,renal function,etc.)and blood coagulation function test etc,were used to provide important basis for the diagnosis and treatment of the disease.In order to ensure laboratory biosafety,it is necessary to first evaluate the harm level of various specimens.In the laboratory biosafety management,the harm level assessment of microorganisms is the core work of biosafety,which is of great significance to guarantee biosafety.As an emergency deployment afcted by the environment,shelter laboratory must possess strong mobility.This paper will explore how to combine the biosafety model of traditional laboratory with the particularity of shelter laboratory to carry out effective work in response to the current epidemic.展开更多
We report the measurement of total molybdenum ion density for L-mode and H-mode plasmas on EAST using spectral lines observation and calculation based on an impurity transport code.A flat-filed extreme ultraviolet spe...We report the measurement of total molybdenum ion density for L-mode and H-mode plasmas on EAST using spectral lines observation and calculation based on an impurity transport code.A flat-filed extreme ultraviolet spectrometer with some spatial resolution is used to obtain the radial profiles of molybdenum spectral line emissions.The absolute calibration for the extreme ultraviolet spectrometer is finished by comparing the calculated bremsstrahlung intensity with the readings of CCD detector.Molybdenum ion transport study is performed using the radial ion density profiles and one-dimensional impurity transport code STRAHL.The total molybdenum density profiles are determined from the transport analysis.The molybdenum density during L-mode and H-mode phases are obtained,which are about 3 and 4 orders of magnitude smaller than the electron density,respectively.An inward pinch is found during the H-mode phase that leads to the peaked profile of molybdenum density.展开更多
The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closel...The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closely related to uranium mineralization.The textures major and trace elements,S-He-Ar isotopes compositions of pyrites in ores of different grade were observed and/or analyzed by optical microscope,scanning electron microscope,electron microprobe,laser ablation inductively coupled plasma mass spectrometry,and noble gas mass spectrometer(Helix-SFT).It is observed that these U-related pyrites are generally euhedral-subhedral with dissolution textures,anhedral variety with colloform texture veinlet and fine particles,and the color of the associated minerals is mostly dark hue,such as purple-black fluorite dark-red hematite,and dark-green chlorite,etc.The analytical results show that the average compositions of major elements in pyrite are FeS1.944.Pyrites are characterized by S-deficiency,low content of Co and Th,and Co/Ni>1which indicate that these ores are of low-temperature hydrothermal origin.We found that the higher the grade of ore,the more deficient in S,the more obvious negative δ^34S,and the higher REE content(close to U-rich granitic pluton)of pyrite.The S-He-Ar isotopic compositions of various varieties of pyrites indicate that the ore-forming fluids mainly come from crust-derived fluids and mixed with mantle-derived fluids.展开更多
A comprehensive account of fungal classification from freshwater habitats is outlined and discussed in the present review based on literature of biodiversity studies and recent morpho-phylogenetic analyses.A total of ...A comprehensive account of fungal classification from freshwater habitats is outlined and discussed in the present review based on literature of biodiversity studies and recent morpho-phylogenetic analyses.A total of 3,870 freshwater fungal species are listed with additional details on the isolation source,habitat,geographical distribution,and molecular data.The Ascomycota(2,968 species,1,018 genera)dominated the freshwater fungal taxa wherein Sordariomycetes(823 species,298 genera)had the largest number,followed by Dothideomycetes(677 species,229 genera),Eurotiomycetes(276 species,49 genera),and Leotiomycetes(260 species,83 genera).Other phyla included in the updated classification of freshwater fungi are:Chytridiomycota(333 species,97 genera),Rozellomycota(221 species,105 genera),Basidiomycota(218 species,100 genera),Blastocladiomycota(47 species,10 genera),Monoblepharomycota(29 species,6 genera),Mucoromycota(19 spe-cies,10 genera),Aphelidiomycota(15 species,3 genera),Entomophthoromycota(6 species,4 genera),Mortierellomycota(5 species,3 genera),Olpidiomycota(4 species,1 genus),Zoopagomycota(3 species,2 genera),and Sanchytriomycota(2 species,2 genera).The freshwater fungi belong to 1,361 genera,386 families and 145 orders.The Pleosporales and Laboulbeniaceae are the largest freshwater fungal order and family comprised of 391 and 185 species,respectively.The most speciose genera are Chitonomyces(87,Laboulbeniomycetes),Verrucaria(50,Eurotiomycetes),Rhizophydium(52,Rhizophydiomycetes),Penicillium(47,Eurotiomycetes),and Candida(42,Saccharomycetes).展开更多
Escherichia coli O157:H7 (E. coli O157:H7) is one of the top pathogens of interest for the development of rapid diagnostic systems for food and water samples. The objective of this research is to develop a rapid, nove...Escherichia coli O157:H7 (E. coli O157:H7) is one of the top pathogens of interest for the development of rapid diagnostic systems for food and water samples. The objective of this research is to develop a rapid, novel electrochemical biosensor based on the use of polypropylene microfiber membranes coated with a conductive polypyrrole and antibody functionalized for the biological capture and detection of E. coli O157:H7 inthe field. Using glutaraldehyde, pathogen specific antibodies are covalently attached to conductive microfiber membranes which are then blocked using a 5% bovine serum albumin solution. The functionalized membranes are then exposed to E. coli O157:H7 cells washed in Butterfield’s phosphate buffer and added to a phosphate-buffer electrolyte solution. When a voltage is applied to the system, the presence of the captured pathogen on the fiber surface results in an increase in resistance at the electrotextile electrode surface, indicating a positive result. In this study, the initial resistance of the membrane in the electrochemical system was established and found to range between 5.8 and 13 . The resistance of the system not associated with the electrotextile fibers was calculated to contribute to only 2.8% of the total system resistance, and found not to be significant. A proof of concept experiment was conducted and determined that the electrotextile electrode was able to differentiate between small changes in a solution’s conductivity associated with the presence of E. coli O157:H7 cells over a concentration range of log 0 - 9 CFU/mL.展开更多
Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity manage...Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of 〉4.5 keV, and a central density ne（0）-2.5×10^19 m^-3. The plasma current was nearly non-inductive （Vloop 〈0.05 V, poloidal beta - 0.9） driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz, 1.4 MW lower hybrid wave at 4.6 GHz, 0.5 MW electron cyclotron heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated ＂hybrid＂ operating scenario of interest to ITER and CFETR.展开更多
The compressibility of shale matrix reflects the effects of reservoir lithology, material composition, pore structure and tectonic deformation. It is important to understand the factors that influence shale matrix com...The compressibility of shale matrix reflects the effects of reservoir lithology, material composition, pore structure and tectonic deformation. It is important to understand the factors that influence shale matrix compressibility(SMC) and their effects on pore size distribution(PSD) heterogeneity in order to evaluate the properties of unconventional reservoirs.In this study, the volumes of pores whose diameters were in the range 6–100 nm were corrected for SMC for 17 shale samples from basins in China using high-pressure mercury intrusion and low-temperature nitrogen gas adsorption analyses,in order to investigate the factors influencing the SMC values. In addition, the variations in fractal dimensions before and after pore volume correction were determined, using single and multifractal models to explain the effects of SMC on PSD heterogeneity. In this process, the applicability of each fractal model for characterizing PSD heterogeneity was determined using statistical analyses. The Menger and Sierpinski single fractal models, the thermodynamic fractal model and a multifractal model were all used in this study. The results showed the following. The matrix compression restricts the segmentation of the fractal dimension curves for the single fractal Menger and Sierpinski models, which leads to a uniformity of PSD heterogeneity for different pore diameters. However, matrix compression has only a weak influence on the results calculated using a thermodynamic model. The SMC clearly affects the multifractal value variations, showing that the fractal dimension values of shale samples under matrix compression are small. Overall PSD heterogeneity becomes small for pores with diameters below 100 nm and the SMC primarily affects the PSD heterogeneity of higher pore volume areas. The comparison of fractal curves before and after correction and the variance analysis indicate that the thermodynamic model is applicable to quantitatively characterize PSD heterogeneity of shale collected from this sampling area. The results sh展开更多
Tungsten(W)is used as the armor material of the International Thermonuclear Experimental Reactor(ITER)divertor and is regarded as the potential first wall material of future fusion reactors.One of the key challenges f...Tungsten(W)is used as the armor material of the International Thermonuclear Experimental Reactor(ITER)divertor and is regarded as the potential first wall material of future fusion reactors.One of the key challenges for the successful application of W in fusion devices is effective control of W at an extremely low concentration in plasma.Understanding and control of W erosion are not only a prerequisite for W impurity control,but also vital concerns to plasma-facing component(PFC)lifetime.Since the application of ITER-like water-cooled full W divertor in EAST in 2014,great efforts were made to inves-tigate W erosion by experiment and simulation.A spectroscopic system was developed to provide a real-time measurement of W sputtering source.Both experiment and simulation results indicate that carbon(C)is the dominant impurity causing W sputtering in L-mode plasmas,which comes from the erosion of C plasma-facing material(PFM)in the lower divertor and the main chamber limiters.The mixture layer on the surface of W PFCs formed through redeposition or the wall coating can effectively suppress W erosion.Increasing the plasma density and radiation can reduce incident ion energy,thus alleviating W sputtering.In H-mode plasmas,control of edge localized mode(ELM)via resonant magnetic perturbation(RMP)proves to be capable of suppressing intra-ELM W erosion.The experiences and lessons from the EAST W divertor are beneficial to the design,manufacturing and operation of ITER and beyond.展开更多
In this paper, we propose a theoretical-information Confidential Procedure Model (CPM) to quantify confidentiality (or information leakage). The advantages of the CPM model include the following: 1) confidentiality lo...In this paper, we propose a theoretical-information Confidential Procedure Model (CPM) to quantify confidentiality (or information leakage). The advantages of the CPM model include the following: 1) confidentiality loss is formalized as a dynamic procedure, instead of a static function, and described via the "waterfall" diagram; 2) confidentiality loss is quantified in a relative manner, i.e., taken as a quantitative metric, the ratio of the conditional entropy being reserved after observing the entropy of the original full confidential information; 3) the optimal attacks including exhaustive attacks as well as all possible attacks that have (or have not even) been discovered, are taken into account when defining the novel concept of the confidential degree. To elucidate the proposed model, we analyze the information leakage in side-channel attacks and the anonymity of DC-net in a quantitative manner.展开更多
Objective:To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis(A.otallensis)on the promastigote stage of Leishmania donovani(L.donovani)as compared to standard drugs and to screen its phyt...Objective:To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis(A.otallensis)on the promastigote stage of Leishmania donovani(L.donovani)as compared to standard drugs and to screen its phytochemical constituents.Methods:Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves.The extract was also evaluated for in vitro antileishmanial activity against L.donavani which is found from the Parasitology Unit of Black Lion Hospital.The result was compared to standard drugs of sodium stibogluconate,milfostin and paramomycin.Results:The extract has a good antileishmanial activity with an IC_(50)of 0.1230μg/mL on L.donovani(AM 563).The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate.The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm.The phytochemical screening of the exudates of A.otallensis showed the presence of phenol,alkaloid and saponin.Conclusions:The methanol extract of the exudates of A.otallensis has a good anti-leishmaniasis activity and this may be attributed to phenol,alkaloid and saponin present in the plant.But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.展开更多
Due to the complicated constitution and high precision requirements of the EAST superconducting tokamak, a meticulous assembling procedure and measurement scheme must be established. The big size and mass of the EAST ...Due to the complicated constitution and high precision requirements of the EAST superconducting tokamak, a meticulous assembling procedure and measurement scheme must be established. The big size and mass of the EAST machine＇s components and complicated configuration with tight installation tolerances call for a highly careful assembling procedure. The assembling procedure consists of three main sub-procedures for the assembling of the base, of the tori of the VV, the vacuum vessel TS and the TF, and of the peripheral parts respectively. Before the assembly, a reference framework has been set up by means of an industrial measurement system with reference fiducial targets fixed on the wall of the test hall. In this paper, the assembling procedure is described in detail, the survey control system of the assembly is discussed, and progress in the assembly work is also reported.展开更多
The northeastern Jiangxi Province ophiolite is located in the SE margin of the Yangtze Block, along the Zhangshudun （Yiyang） Xingangshan （Dexing）, ophiolite belt extending northeast for about 100kin （Zhou, 1989; ...The northeastern Jiangxi Province ophiolite is located in the SE margin of the Yangtze Block, along the Zhangshudun （Yiyang） Xingangshan （Dexing）, ophiolite belt extending northeast for about 100kin （Zhou, 1989; Li et al., 1997）. The original sequence of the NE Jiangxi ophiolite suite has been structurally disrupted and enclosed by a strongly foliated flysch sequence. Most of the dismembered peridotites of NEJXO are highly serpentinized, requiring care in applying petrochemistry and geochemistry to distinguish their tectonic setting,展开更多
A present status of the diagnostics in EAST is presented. As a very important step of the EAST project, tens of diagnostics were employed for operation and protection of the machine, plasma control and physics analysi...A present status of the diagnostics in EAST is presented. As a very important step of the EAST project, tens of diagnostics were employed for operation and protection of the machine, plasma control and physics analysis to accommodate requirement for the study on plasma performance in EAST with upgraded radio frequency （RF） injection power up to 4 MW （both LHCD and ICRF） in the forthcoming years. Recently, new diagnostics are set up to provide several profiles of key plasma parameters for the further evaluation and better understanding of the plasma performance and physics in EAST, including a 25-channel Thomson scattering system for density and electron temperature, a metal bolometry for radiated power, an X-ray crystal spectroscopy for both ion and electron temperatures and plasma rotation velocity, etc. It is expected that these diagnostics would play an important role in data analysis and interpretation combined with integrated modeling.展开更多
基金Financial support comes from China National Natural Science Foundation(Grant No.51974352)as well as from China University of Petroleum(East China)(Grant Nos.2018000025 and 2019000011)。
文摘In order to investigate the problem of long-term strength retrogression in oil well cement systems exposed to high pressure and high temperature(HPHT)curing conditions,various influencing factors,including cement sources,particle sizes of silica flour,and additions of silica fume,alumina,colloidal iron oxide and nano-graphene,were investigated.To simulate the environment of cementing geothermal wells and deep wells,cement slurries were directly cured at 50 MPa and 200?C.Mineral compositions(as determined by X-ray diffraction Rietveld refinement),water permeability,compressive strength and Young’s modulus were used to evaluate the qualities of the set cement.Short-term curing(2e30 d)test results indicated that the adoption of 6 m m ultrafine crystalline silica played the most important role in stabilizing the mechanical properties of oil well cement systems,while the addition of silica fume had a detrimental effect on strength stability.Long-term curing(2e180 d)test results indicated that nano-graphene could stabilize the Young’s modulus of oil well cement systems.However,none of the ad-mixtures studied here can completely prevent the strength retrogression phenomenon due to their inability to stop the conversion of amorphous to crystalline phases.
文摘BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an essential therapeutic tool for biliary and pancreatic diseases.Frail and elderly patients,especially those aged≥90 years are generally considered a higher-risk population for ERCP-related complications.AIM To investigate outcomes of ERCP in the Non-agenarian population(≥90 years)concerning Frailty.METHODS This is a cohort study using the 2018-2020 National Readmission Database.Patients aged≥90 were identified who underwent ERCP,using the international classification of diseases-10 code with clinical modification.Johns Hopkins’s adjusted clinical groups frailty indicator was used to classify patients as frail and non-frail.The primary outcome was mortality,and the secondary outcomes were morbidity and the 30 d readmission rate related to ERCP.We used univariate and multivariate regression models for analysis.RESULTS A total of 9448 patients were admitted for any indications of ERCP.Frail and non-frail patients were 3445(36.46%)and 6003(63.53%)respectively.Indications for ERCP were Choledocholithiasis(74.84%),Biliary pancreatitis(9.19%),Pancreatico-biliary cancer(7.6%),Biliary stricture(4.84%),and Cholangitis(1.51%).Mortality rates were higher in frail group[adjusted odds ratio(aOR)=1.68,P=0.02].The Intra-procedural complications were insigni-ficant between the two groups which included bleeding(aOR=0.72,P=0.67),accidental punctures/lacerations(aOR=0.77,P=0.5),and mechanical ventilation rates(aOR=1.19,P=0.6).Post-ERCP complication rate was similar for bleeding(aOR=0.72,P=0.41)and post-ERCP pancreatitis(aOR=1.4,P=0.44).Frail patients had a longer length of stay(6.7 d vs 5.5 d)and higher mean total charges of hospitalization($78807 vs$71392)compared to controls(P<0.001).The 30 d all-cause readmission rates between frail and non-frail patients were similar(P=0.96).CONCLUSION There was a significantly higher mortality risk and healthcare burden amongst nonagenarian frail patients undergoing ERCP compared to non-frail.Larger studies are warrant
基金supported by the National Natural Science Foundation of China (No.41930428)the scientific research start-up fund for doctors of East China University of Technology (No.DHBK2019066)the science and technology research project of Jiangxi Education Department (No.GJJ2200754)。
文摘The formation of many hydrothermal gold deposits is closely related to iron-rich rocks. The host rocks of the Madiyi Formation of the Mid-to Late Neoproterozoic Banxi Group for the Woxi Au(-Sb-W) deposit, which is located in western Hunan Province of the western Jiangnan Orogen, South China, is rich in hematite, which provides a good example for studying the relationship between the formation of gold deposit and iron-rich rocks. Field investigation and petrographic observation on the unaltered, weakly altered and strongly altered rocks demonstrate that the bleaching is caused by a combination of carbonatization, sulfidation and sericitization. Mass balance calculation suggests that, during decolourization there is no change in TFe_(2)O_(3), while FeO is gained and Fe_(2)O_(3)is lost. Geochemical modeling found that Au was mainly present as AuHS(aq) and Au(HS)-2, and that the water-rock interactions decreased the sulfur fugacity which destroyed the stability of such aqueous complexes. Combined with the locally occurred native gold in quartz veins, it is concluded that the major gold precipitation mechanisms are sulfidation and fluid boiling. Based on previous geochronological and geochemical research further gold mineralization is proposed to be generated by deep sourced magmatic or metamorphic fluid migrated upward along the Woxi fault, and the iron-rich Madiyi Formation is the idea chemical trap for gold deposition. The decrease of sulfur contents caused by fluid-rock interactions and fluid boiling are the major mechanisms for gold mineralization.
基金supported by the National Natural Science Foundation of China(Nos.11671135,11871213,11901255)the Natural Science Foundation of Shanghai(No.19ZR1411800)。
文摘In this work,we investigate a generalization of the classical capacitated arc routing problem,called the Multi-depot Capacitated Arc Routing Problem(MCARP).We give exact and approximation algorithms for different variants of the MCARP.First,we obtain the first constant-ratio approximation algorithms for the MCARP and its nonfixed destination version.Second,for the multi-depot rural postman problem,i.e.,a special case of the MCARP where the vehicles have infinite capacity,we develop a(2-1/2k+1)-approximation algorithm(k denotes the number of depots).Third,we show the polynomial solvability of the equal-demand MCARP on a line and devise a 2-approximation algorithm for the multi-depot capacitated vehicle routing problem on a line.Lastly,we conduct extensive numerical experiments on the algorithms for the multi-depot rural postman problem to show their effectiveness.
基金jointly supported by the National Key R&D Program of China(Grant No.2016YFC0600201)China Geological Survey project(Grant Nos.DD20190012,DD20160082)the National Natural Science Foundation of China(Grant Nos.92062108,41630320,41574133)。
文摘The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallogeny of the deposit have included its timing,the ore-controlling structures and sedimentary host rocks and their implications for mineral exploration.However,the deep nappe structural style of Taqian-Fuchun metallogenic belt that hosts the W deposit,and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined,which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit.Modern 3 D geological modeling is an important tool for the exploration of concealed orebodies,especially in brownfield environments.There are obvious density contrast and weak magnetic contrast in the ore-controlling strata and granite at the periphery of the deposit,which lays a physical foundation for solving the 3 D spatial problems of the ore-controlling geological body in the deep part of the study area through gravity and magnetic modeling.Gravity data(1:50000)and aeromagnetic data(1:50000)from the latest geophysical surveys of 2016-2018 have been used,firstly,to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion.Then,on the basis of the analysis of the relationship between physical properties and lithology,under the constraints of surface geology and borehole data,human-computer interactive gravity and magnetic inversion for 18 cross-sections were completed.Finally,the 3 D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections,and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained,initially realizing―transparency‖for ore-controlling bodies.According the analysis of the geophysical,geochemical,and geological characteristics of the Zhuxi tungsten deposit,we di
基金This project was supported by Major Research Projects of Sichuan Health Commission(No.16ZD026).
文摘At the end of 2019,the novel coronavirus infection outbroke in Wuhan,Hubei Province.On Feb.2,2020,Wuhan,as the worst-hit region,began to build“shelter hospital”rapidly to treat patients with mild ilness.The shelter hospital has multiple functions such as emergency treatment,surgical treatment and clinical test,which can adapt to emergency medical rescue tasks.Based on the characteristics that shelter hospital only treats patients with mild ilness,tests of shelter laboratory,including coronavirus nucleic acid detection,IgM/IgG antibody serology detection,monitoring and auxiliary diagnosis and/or a required blood routine,urine routine,C-reactive protein,calcitonin original,biochemical indicators(liver enzymes,myocardial enzymes,renal function,etc.)and blood coagulation function test etc,were used to provide important basis for the diagnosis and treatment of the disease.In order to ensure laboratory biosafety,it is necessary to first evaluate the harm level of various specimens.In the laboratory biosafety management,the harm level assessment of microorganisms is the core work of biosafety,which is of great significance to guarantee biosafety.As an emergency deployment afcted by the environment,shelter laboratory must possess strong mobility.This paper will explore how to combine the biosafety model of traditional laboratory with the particularity of shelter laboratory to carry out effective work in response to the current epidemic.
基金National Key Research and Development Program of China(Grant No.2017YFE031300)the Key Program of Research and Development of Hefei Science Center of China(Grant No.2017HSC-KPRD002)+4 种基金the National Natural Science Foundation of China(Grant No.11805231)the Natural Science Foundation of Anhui Province of China(Grant Nos.1908085J01,1808085QA14,and 1908085QF274)the ASIPP Science and Research Fund of China(Grant No.DSJJ-17-03)Collaborative Innovation Program of Hefei Science Center,CAS(Grant No.2019HSC-CIP005)Anqing Normal University Research Project,China(Grant Nos.043-180079 and 044-140001000024).
文摘We report the measurement of total molybdenum ion density for L-mode and H-mode plasmas on EAST using spectral lines observation and calculation based on an impurity transport code.A flat-filed extreme ultraviolet spectrometer with some spatial resolution is used to obtain the radial profiles of molybdenum spectral line emissions.The absolute calibration for the extreme ultraviolet spectrometer is finished by comparing the calculated bremsstrahlung intensity with the readings of CCD detector.Molybdenum ion transport study is performed using the radial ion density profiles and one-dimensional impurity transport code STRAHL.The total molybdenum density profiles are determined from the transport analysis.The molybdenum density during L-mode and H-mode phases are obtained,which are about 3 and 4 orders of magnitude smaller than the electron density,respectively.An inward pinch is found during the H-mode phase that leads to the peaked profile of molybdenum density.
基金supported by the Science and Technology Research Project of China Nuclear Geology(No.2110400024)Uranium Geological Exploration Fund Project of China National Nuclear Corporation(No.J2012-03)+1 种基金Uranium Mine Exploration Project of Hunan Nuclear Geology(No.DK30620170512)Scientific Research Program of Hunan Nuclear Geology(No.KYQ-306-01)。
文摘The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closely related to uranium mineralization.The textures major and trace elements,S-He-Ar isotopes compositions of pyrites in ores of different grade were observed and/or analyzed by optical microscope,scanning electron microscope,electron microprobe,laser ablation inductively coupled plasma mass spectrometry,and noble gas mass spectrometer(Helix-SFT).It is observed that these U-related pyrites are generally euhedral-subhedral with dissolution textures,anhedral variety with colloform texture veinlet and fine particles,and the color of the associated minerals is mostly dark hue,such as purple-black fluorite dark-red hematite,and dark-green chlorite,etc.The analytical results show that the average compositions of major elements in pyrite are FeS1.944.Pyrites are characterized by S-deficiency,low content of Co and Th,and Co/Ni>1which indicate that these ores are of low-temperature hydrothermal origin.We found that the higher the grade of ore,the more deficient in S,the more obvious negative δ^34S,and the higher REE content(close to U-rich granitic pluton)of pyrite.The S-He-Ar isotopic compositions of various varieties of pyrites indicate that the ore-forming fluids mainly come from crust-derived fluids and mixed with mantle-derived fluids.
基金Thailand Research Fund“The future of specialist fungi in a changing climate:baseline data for generalist and specialist fungi associated with ants,Rhodo-dendron species and Dracaena species”(DBG6080013)“Impact of climate change on fungal diversity and biogeography in the Greater Mekong Sub-region”(RDG6130001).
文摘A comprehensive account of fungal classification from freshwater habitats is outlined and discussed in the present review based on literature of biodiversity studies and recent morpho-phylogenetic analyses.A total of 3,870 freshwater fungal species are listed with additional details on the isolation source,habitat,geographical distribution,and molecular data.The Ascomycota(2,968 species,1,018 genera)dominated the freshwater fungal taxa wherein Sordariomycetes(823 species,298 genera)had the largest number,followed by Dothideomycetes(677 species,229 genera),Eurotiomycetes(276 species,49 genera),and Leotiomycetes(260 species,83 genera).Other phyla included in the updated classification of freshwater fungi are:Chytridiomycota(333 species,97 genera),Rozellomycota(221 species,105 genera),Basidiomycota(218 species,100 genera),Blastocladiomycota(47 species,10 genera),Monoblepharomycota(29 species,6 genera),Mucoromycota(19 spe-cies,10 genera),Aphelidiomycota(15 species,3 genera),Entomophthoromycota(6 species,4 genera),Mortierellomycota(5 species,3 genera),Olpidiomycota(4 species,1 genus),Zoopagomycota(3 species,2 genera),and Sanchytriomycota(2 species,2 genera).The freshwater fungi belong to 1,361 genera,386 families and 145 orders.The Pleosporales and Laboulbeniaceae are the largest freshwater fungal order and family comprised of 391 and 185 species,respectively.The most speciose genera are Chitonomyces(87,Laboulbeniomycetes),Verrucaria(50,Eurotiomycetes),Rhizophydium(52,Rhizophydiomycetes),Penicillium(47,Eurotiomycetes),and Candida(42,Saccharomycetes).
文摘Escherichia coli O157:H7 (E. coli O157:H7) is one of the top pathogens of interest for the development of rapid diagnostic systems for food and water samples. The objective of this research is to develop a rapid, novel electrochemical biosensor based on the use of polypropylene microfiber membranes coated with a conductive polypyrrole and antibody functionalized for the biological capture and detection of E. coli O157:H7 inthe field. Using glutaraldehyde, pathogen specific antibodies are covalently attached to conductive microfiber membranes which are then blocked using a 5% bovine serum albumin solution. The functionalized membranes are then exposed to E. coli O157:H7 cells washed in Butterfield’s phosphate buffer and added to a phosphate-buffer electrolyte solution. When a voltage is applied to the system, the presence of the captured pathogen on the fiber surface results in an increase in resistance at the electrotextile electrode surface, indicating a positive result. In this study, the initial resistance of the membrane in the electrochemical system was established and found to range between 5.8 and 13 . The resistance of the system not associated with the electrotextile fibers was calculated to contribute to only 2.8% of the total system resistance, and found not to be significant. A proof of concept experiment was conducted and determined that the electrotextile electrode was able to differentiate between small changes in a solution’s conductivity associated with the presence of E. coli O157:H7 cells over a concentration range of log 0 - 9 CFU/mL.
基金supported by the National Magnetic Confinement Fusion Science Foundation of China(Nos.2015GB102000 and 2014GB103000)
文摘Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of 〉4.5 keV, and a central density ne（0）-2.5×10^19 m^-3. The plasma current was nearly non-inductive （Vloop 〈0.05 V, poloidal beta - 0.9） driven by a combination of 0.6 MW lower hybrid wave at 2.45 GHz, 1.4 MW lower hybrid wave at 4.6 GHz, 0.5 MW electron cyclotron heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated ＂hybrid＂ operating scenario of interest to ITER and CFETR.
基金funded by grants from the Natural Science Foundation of Shandong Province, China (Nos. ZR2021QD072 and ZR2020QD040)。
文摘The compressibility of shale matrix reflects the effects of reservoir lithology, material composition, pore structure and tectonic deformation. It is important to understand the factors that influence shale matrix compressibility(SMC) and their effects on pore size distribution(PSD) heterogeneity in order to evaluate the properties of unconventional reservoirs.In this study, the volumes of pores whose diameters were in the range 6–100 nm were corrected for SMC for 17 shale samples from basins in China using high-pressure mercury intrusion and low-temperature nitrogen gas adsorption analyses,in order to investigate the factors influencing the SMC values. In addition, the variations in fractal dimensions before and after pore volume correction were determined, using single and multifractal models to explain the effects of SMC on PSD heterogeneity. In this process, the applicability of each fractal model for characterizing PSD heterogeneity was determined using statistical analyses. The Menger and Sierpinski single fractal models, the thermodynamic fractal model and a multifractal model were all used in this study. The results showed the following. The matrix compression restricts the segmentation of the fractal dimension curves for the single fractal Menger and Sierpinski models, which leads to a uniformity of PSD heterogeneity for different pore diameters. However, matrix compression has only a weak influence on the results calculated using a thermodynamic model. The SMC clearly affects the multifractal value variations, showing that the fractal dimension values of shale samples under matrix compression are small. Overall PSD heterogeneity becomes small for pores with diameters below 100 nm and the SMC primarily affects the PSD heterogeneity of higher pore volume areas. The comparison of fractal curves before and after correction and the variance analysis indicate that the thermodynamic model is applicable to quantitatively characterize PSD heterogeneity of shale collected from this sampling area. The results sh
基金National Natural Science Foundation of China(NSFC)(Grant No.11575243)the National Key Research and Development Program of China(Grant Nos.2017YFE0301300,2017YFA0402500)the Users with Excellence Project of Hefei Science Center CAS(Grant No.2018HSC-UE008).
文摘Tungsten(W)is used as the armor material of the International Thermonuclear Experimental Reactor(ITER)divertor and is regarded as the potential first wall material of future fusion reactors.One of the key challenges for the successful application of W in fusion devices is effective control of W at an extremely low concentration in plasma.Understanding and control of W erosion are not only a prerequisite for W impurity control,but also vital concerns to plasma-facing component(PFC)lifetime.Since the application of ITER-like water-cooled full W divertor in EAST in 2014,great efforts were made to inves-tigate W erosion by experiment and simulation.A spectroscopic system was developed to provide a real-time measurement of W sputtering source.Both experiment and simulation results indicate that carbon(C)is the dominant impurity causing W sputtering in L-mode plasmas,which comes from the erosion of C plasma-facing material(PFM)in the lower divertor and the main chamber limiters.The mixture layer on the surface of W PFCs formed through redeposition or the wall coating can effectively suppress W erosion.Increasing the plasma density and radiation can reduce incident ion energy,thus alleviating W sputtering.In H-mode plasmas,control of edge localized mode(ELM)via resonant magnetic perturbation(RMP)proves to be capable of suppressing intra-ELM W erosion.The experiences and lessons from the EAST W divertor are beneficial to the design,manufacturing and operation of ITER and beyond.
基金supported by the National Natural Science Foundation of China under Grants No.61172085,No.61272536,No.11061130539,No.61103221,No.61271118,No.61021004
文摘In this paper, we propose a theoretical-information Confidential Procedure Model (CPM) to quantify confidentiality (or information leakage). The advantages of the CPM model include the following: 1) confidentiality loss is formalized as a dynamic procedure, instead of a static function, and described via the "waterfall" diagram; 2) confidentiality loss is quantified in a relative manner, i.e., taken as a quantitative metric, the ratio of the conditional entropy being reserved after observing the entropy of the original full confidential information; 3) the optimal attacks including exhaustive attacks as well as all possible attacks that have (or have not even) been discovered, are taken into account when defining the novel concept of the confidential degree. To elucidate the proposed model, we analyze the information leakage in side-channel attacks and the anonymity of DC-net in a quantitative manner.
文摘Objective:To evaluate the antileishmanial activity of methanolic extract of Aloe otallensis(A.otallensis)on the promastigote stage of Leishmania donovani(L.donovani)as compared to standard drugs and to screen its phytochemical constituents.Methods:Phytochemical screening was done by using the method mentioned by Evans and Trease on methanolic extract of the exudates of Aloe otallensis leaves.The extract was also evaluated for in vitro antileishmanial activity against L.donavani which is found from the Parasitology Unit of Black Lion Hospital.The result was compared to standard drugs of sodium stibogluconate,milfostin and paramomycin.Results:The extract has a good antileishmanial activity with an IC_(50)of 0.1230μg/mL on L.donovani(AM 563).The experimental data showed that relatively it had better activity than paramomycin and milfostin but less activity than sodium stibogluconate.The data analyses were done by GraphPad Prism version 5 software after it was read by ELISA reader at the wave length of 650 nm.The phytochemical screening of the exudates of A.otallensis showed the presence of phenol,alkaloid and saponin.Conclusions:The methanol extract of the exudates of A.otallensis has a good anti-leishmaniasis activity and this may be attributed to phenol,alkaloid and saponin present in the plant.But it needs further analysis for the conformation of which constituent presents in high concentration to know which one has the strongest effect.
基金The project supported by the National Meg-science Engineering Project of Chinese Government and the Chinese Academy of Sciences (SYKXD04)
文摘Due to the complicated constitution and high precision requirements of the EAST superconducting tokamak, a meticulous assembling procedure and measurement scheme must be established. The big size and mass of the EAST machine＇s components and complicated configuration with tight installation tolerances call for a highly careful assembling procedure. The assembling procedure consists of three main sub-procedures for the assembling of the base, of the tori of the VV, the vacuum vessel TS and the TF, and of the peripheral parts respectively. Before the assembly, a reference framework has been set up by means of an industrial measurement system with reference fiducial targets fixed on the wall of the test hall. In this paper, the assembling procedure is described in detail, the survey control system of the assembly is discussed, and progress in the assembly work is also reported.
基金financially supported by the National Natural Science Foundation of China(No.41262002)the Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense (No. 2012RGET06)
文摘The northeastern Jiangxi Province ophiolite is located in the SE margin of the Yangtze Block, along the Zhangshudun （Yiyang） Xingangshan （Dexing）, ophiolite belt extending northeast for about 100kin （Zhou, 1989; Li et al., 1997）. The original sequence of the NE Jiangxi ophiolite suite has been structurally disrupted and enclosed by a strongly foliated flysch sequence. Most of the dismembered peridotites of NEJXO are highly serpentinized, requiring care in applying petrochemistry and geochemistry to distinguish their tectonic setting,
基金supported in part by National Natural Science Foundation of China (Nos. 10935004, 10775041)Sino-Japan Core University Program in Plasma Physics and Fusion Study
文摘A present status of the diagnostics in EAST is presented. As a very important step of the EAST project, tens of diagnostics were employed for operation and protection of the machine, plasma control and physics analysis to accommodate requirement for the study on plasma performance in EAST with upgraded radio frequency （RF） injection power up to 4 MW （both LHCD and ICRF） in the forthcoming years. Recently, new diagnostics are set up to provide several profiles of key plasma parameters for the further evaluation and better understanding of the plasma performance and physics in EAST, including a 25-channel Thomson scattering system for density and electron temperature, a metal bolometry for radiated power, an X-ray crystal spectroscopy for both ion and electron temperatures and plasma rotation velocity, etc. It is expected that these diagnostics would play an important role in data analysis and interpretation combined with integrated modeling.
