The oil and gas potential of the Yan'an Formation in the Ordos Basin has yet to be fully tapped. In this study, the pore structure, mobile fluid saturation, and water flooding micro-mechanism of the Yan'an For...The oil and gas potential of the Yan'an Formation in the Ordos Basin has yet to be fully tapped. In this study, the pore structure, mobile fluid saturation, and water flooding micro-mechanism of the Yan'an Formation sandstone are systematically studied through the application of a series of rock physics and fluid experiments. The results show that there is a good positive correlation between porosity and permeability, and the reservoirs are divided into types Ⅰ, Ⅱ, and Ⅲ. Mercury injection tests show that the average pore throat radius of the oil-bearing reservoir ranges from 1 to 7 μm. The displacement pressure of the Yan'an Formation is also relatively low, and it decreases from 0.1 MPa to 0.01 MPa as the rock porosity increases from 11% to 18%. NMR tests show that small (diameter <0.5 μm) and medium pores (diameter ranging from 0.5 to 2.5 μm) are predominant in the reservoir. Different types of reservoirs have different characteristics of relative permeability curve. In addition, when the average oil recovery rate is less than 1 ml/min, the oil displacement efficiency increases faster. However, when the average oil recovery rate is between 1–3.5 ml/min, the oil displacement efficiency is maintained at around 27%–30%. Physical properties of the reservoir, pore-throat structure, experimental pressure difference, and pore volume injected — all have significant effects on oil displacement efficiency. For Type Ⅰ and Type Ⅱ reservoirs, the increase of the pore volume injected has a significant effect on oil displacement efficiency. However, for Type Ⅲ reservoirs, the change of pore volume injected has insignificant effect on oil displacement efficiency. This study provides a reference for the formulation of estimated ultimate recovery (EUR) measures for similar sandstone reservoirs.展开更多
A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-...A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process.展开更多
Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a j...Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.展开更多
The Hi-CLIMB seismic array is located in the central-western Tibetan Plateau.The H-κ-c method(Li JT et al.,2019)was applied to receiver function data on the HiCLIMB,which corrects the back-azimuthal variations in the...The Hi-CLIMB seismic array is located in the central-western Tibetan Plateau.The H-κ-c method(Li JT et al.,2019)was applied to receiver function data on the HiCLIMB,which corrects the back-azimuthal variations in the arrival times of Ps and crustal multiples caused by crustal anisotropy and dipping interfaces before performing H-κstacking.Compared to the traditional H-κmethod,the H-κstacking results after harmonic corrections showed considerable improvements,including greatly reduced errors,significantly less scattered H(crustal thickness)andκ(crustal v_(P)/v_(S)ratio)values,and clearer patterns of H andκin different Tibetan blocks.This demonstrates that the H-κ-c method works well even for regions with complex crustal structures,such as the Tibetan Plateau,when there are helpful references from nearby stations or other constraints.The variation in crustal thickness agrees with previous studies but tends to be relatively shallower beneath most of the plateau.Two regions with particularly high crustal v_(P)/v_(S)were observed,namely,one in the northern Himalaya block and beneath the YarlungZangbo suture,and the other in the Qiangtang block.Their correlation with mid-crust low S velocities from previous studies suggests the possible presence of fluid or partial melt in the two regions,which may have implications for the crustal flow model.In contrast,the Lhasa block had relatively lower crustal v_(P)/v_(S)and relatively higher crustal S velocity within the plateau,which is interpreted to be mechanically stronger than the Himalaya and Qiangtang blocks,and without mid-crust partial melt.展开更多
The Chinese mainland is subject to complicated plate interactions that give rise to its complex structure and tectonics. While several seismic velocity models have been developed for the Chinese mainland, apparent dis...The Chinese mainland is subject to complicated plate interactions that give rise to its complex structure and tectonics. While several seismic velocity models have been developed for the Chinese mainland, apparent discrepancies exist and, so far, little effort has been made to evaluate their reliability and consistency. Such evaluations are important not only for the application and interpretation of model results but also for future model improvement. To address this problem, here we compare five published shear-wave velocity models with a focus on model consistency. The five models were derived from different datasets and methods (i.e., body waves, surface waves from earthquakes, surface waves from noise interferometry, and full waves) and interpolated into uniform horizontal grids (0.5° × 0.5°) with vertical sampling points at 5 km, 10 km, and then 20 km intervals to a depth of 160 km below the surface, from which we constructed an averaged model (AM) as a common reference for comparative study. We compare both the absolute velocity values and perturbation patterns of these models. Our comparisons show that the models have large (> 4%) differences in absolute values, and these differences are independent of data coverage and model resolution. The perturbation patterns of the models also show large differences, although some of the models show a high degree of consistency within certain depth ranges. The observed inconsistencies may reflect limited model resolution but, more importantly, systematic differences in the datasets and methods employed. Thus, despite several seismic models being published for this region, there is significant room for improvement. In particular, the inconsistencies in both data and methodologies need to be resolved in future research. Finally, we constructed a merged model (ChinaM-S1.0) that incorporates the more robust features of the five published models. As the existing models are constrained by different datasets and methods, the merged model serves as a new type of reference model that incorporates the common features from the joint datasets and methods for the shear-wave velocity structure of the Chinese mainland lithosphere.展开更多
Exosomes are extracellular vesicles with a 30–150 nm diameter originating from endosomes.In recent years,scientists have regarded exosomes as an ideal small molecule carrier for the targeted treatment of Alzheimer’s...Exosomes are extracellular vesicles with a 30–150 nm diameter originating from endosomes.In recent years,scientists have regarded exosomes as an ideal small molecule carrier for the targeted treatment of Alzheimer’s disease(AD)across the blood-brain barrier due to their nanoscale size and low immunogenicity.A large amount of evidence shows that exosomes are rich in biomarkers,and it has been found that the changes in biomarker content in blood,cerebrospinal fluid,and urine are often associated with the onset of AD patients.In this paper,some recent advances in the use of exosomes in the treatment of AD are reviewed,and various exosome markers and some latest detection methods are summarized to provide some evidence for the detection or treatment of AD by exosomes.展开更多
W/Cu Functionally Graded Materials (FGM) was designed not only for reducing the thermal stress caused by the mismatch of thermal expansion coefficients, but also for combining the features of W, Mo - high plasma-erosi...W/Cu Functionally Graded Materials (FGM) was designed not only for reducing the thermal stress caused by the mismatch of thermal expansion coefficients, but also for combining the features of W, Mo - high plasma-erosion resistance and the advantages of Cu - high heat conductivity and ductility. Four different fabrication processes for W/Cu or Mo/Cu, including hot-pressing, Cu infiltration of sintered porosity-graded W skeleton, spark plasma sintering and plasma spraying, were investigated and compared. It was foundthat the hot-pressing process is difficult to keep the designed composition gradient, while the other three processes are successful in making W/Cu or Mo/Cu FGM. Meanwhile, microstructures and composition gradients are analyzed with SEM and EDAX.展开更多
The complex tectonic background of East Asia makes it an ideal region for investigating the evolution of the continental lithosphere,for which high-resolution lithospheric structural models are essential.In this study...The complex tectonic background of East Asia makes it an ideal region for investigating the evolution of the continental lithosphere,for which high-resolution lithospheric structural models are essential.In this study,we measured Rayleigh-wave phase-velocity dispersion curves at periods of 10-120 s and group velocity dispersion curves at periods of 10-140 s using event records from more than 1,000 seismic stations in and around China.By jointly inverting new and previously published dispersion data from ambient noise and earthquakes,we developed a high-resolution shear-wave velocity model down to a depth of~300 km beneath East Asia.Our model revealed heterogeneous lithospheric structures beneath East Asia,and allowed us to investigate the velocity structure of the entire lithosphere.We also derived crustal and lithospheric thickness models from the three-dimensional(3D)shear-wave model,revealing strong spatial heterogeneity and a general thinning trend of lithospheric thickness from west to east across the study region.Overall,our models reveal important lithospheric features beneath East Asia and provide a valuable baseline dataset for understanding continental-scale dynamics and evolution.展开更多
Objective:Acute myeloid leukemia(AML)is primarily a malignant disorder affecting the elderly.We aimed to compare the outcomes of different treatment patterns in elderly AML patients and to propose a prognostic scoring...Objective:Acute myeloid leukemia(AML)is primarily a malignant disorder affecting the elderly.We aimed to compare the outcomes of different treatment patterns in elderly AML patients and to propose a prognostic scoring system that could predict survival and aid therapeutic decisions.Methods:Patients aged≥60 years who had been diagnosed with AML at 7 hospitals in China were enrolled(n=228).Treatment patterns included standard chemotherapy,low intensity therapy,and best supportive care(BSC).Results:The early mortality rates were 31%,6.8%,and 6.3%for the BSC,low intensity therapy,and standard chemotherapy groups,respectively.The complete remission rate of the standard chemotherapy group was higher than that of the low intensity therapy group.The median overall survival(OS)was 561 days and 222 days for the standard chemotherapy and low intensity therapy groups,respectively,and were both longer than that of the BSC group(86 days).Based on multivariate analyses,we defined a prognostic scoring system that enabled classification of patients into 3 risk groups,in an attempt to predict the OS of patients receiving chemotherapies and low intensity therapies.Low and intermediate risk patients benefited more from standard chemotherapies than from low intensity therapies.However,the median OS was comparable between standard chemotherapies and low intensity therapies in high risk patients.Conclusions:Our prognostic scoring system could predict survival and help select appropriate therapies for elderly AML patients.Standard chemotherapy is important for elderly AML patients,particularly for those categorized into low and intermediate risk groups.展开更多
The distribution transformer is the mainstay of the power system.Its internal temperature study is desirable for its safe operation in the power system.The purpose of the present study is to determine direct comprehen...The distribution transformer is the mainstay of the power system.Its internal temperature study is desirable for its safe operation in the power system.The purpose of the present study is to determine direct comprehensive thermal distribution in the distribution transformers for different loading conditions.To achieve this goal,the temperature distribution in the oil,core,and windings are studied at each loading.An experimental study is performed with a 10/0.38 kV,10 kVA oil–immersed transformer equipped with forty–two PT100 sensors(PTs)for temperature measurement installed inside during its manufacturing process.All possible locations for the hottest spot temperature(HST)are considered that made by finite element analysis(FEA)simulation and losses calculations.A resistive load is made to achieve 80%to 120%loading of the test transformer for this experiment.Working temperature is measured in each part of the transformer at all provided loading conditions.It is observed that temperature varies with loading throughout the transformer,and a detailed map of temperature is obtained in the whole test transformer.From these results,the HST stays in the critical section of the primary winding at all loading conditions.This work is helpful to understand the complete internal temperature layout and the location of the HST in distribution transformers.展开更多
Driven by the continuous penetration of high data rate services and applications,a large amount of unregulated visible light spectrum is used for communication to fully meet the needs of 6th generation(6G)mobile techn...Driven by the continuous penetration of high data rate services and applications,a large amount of unregulated visible light spectrum is used for communication to fully meet the needs of 6th generation(6G)mobile technologies.Visible light communication(VLC)faces many challenges as a solution that complements existing radio frequency(RF)networks.This paper studies the optimal configuration of LEDs in indoor environments under the constraints of illumination and quality of experience(QoE).Based on the Voronoi tessellation(VT)and centroidal Voronoi tessellation(CVT)theory,combined with the Lloyd’s algorithm,we propose two approaches for optimizing LED deployments to meet the illumination and QoE requirements of all users.Focusing on(i)the minimization of the number of LEDs to be installed in order to meet illumination and average QoE constraints,and(ii)the maximization of the average QoE of users to be served with a fixed number of LEDs.Monte Carlo simulations are carried out for different user distribution compared with hexagonal,square and VT deployment.The simulation results illustrate that under the same conditions,the proposed deployment approach can provide less LEDs and achieve better QoE performance.展开更多
We study the vertical distribution of the highly inclined galaxies from the Continuum Halos in Nearby Galaxies—an EVLA Survey(CHANG-ES).We explore the feasibility of photometrically deriving the HⅠdisk scale heights...We study the vertical distribution of the highly inclined galaxies from the Continuum Halos in Nearby Galaxies—an EVLA Survey(CHANG-ES).We explore the feasibility of photometrically deriving the HⅠdisk scale heights from the moment-0 images of the relatively edge-on galaxies with inclination>80°,by quantifying the systematic broadening effects and thus deriving correction equations for direct measurements.The corrected HⅠdisk scale heights of the relatively edge-on galaxies from the CHANG-ES sample show trends consistent with the quasiequilibrium model of the vertical structure of gas disks.The procedure provides a convenient way to derive the scale heights and can easily be applied to statistical samples in the future.展开更多
Objective:To study the relationship of the telomerase activity and the p53 gene mutation in cardiac cancer. Methods:Telomerase activity and the p53 gene mutation were detected in 46 case of cardiac cancer,peri-cancero...Objective:To study the relationship of the telomerase activity and the p53 gene mutation in cardiac cancer. Methods:Telomerase activity and the p53 gene mutation were detected in 46 case of cardiac cancer,peri-cancerous and 30 case of normal mucosa by TRAP-ELISA and PCR-SSCP.Results:The rate of expression of telomerase activity in cardiac cancer,peri-cancerous and normal mucosa were 82.61%(38/46),43.48%(20/46)and 13.33%(4/30)respectively.The rate of Exon5→8 of p53 gene mutation were 39.13%(18/46),4.35%(2/46)and 0.00%respectively.There was significant differ- ence between group cancer and without cancer(P<0.01).Mean of A value of telomerase is 1.89±0.41 in cancer group and were 1.49±0.43,0.54±0.45 respectively in peri-canvcerous and normal mucosa,there were significant differences in cancer group and group of without cancer(P<0.05).The rate of p53 gene mutations in group of expression of telomerase activity was 44.74%(17/38),and 12.50%(1/8)in without expression of telomerase activity.There were significant differences between the two groups.Conclusion:The rate of expression of telomerase activity and mean of A value of telomerase in cardiac cancer were obviously higher than without cancer,which indicating telomerase activity was closely related with the occurrence of cardiac cancer.P53 gene mutation in cardiac cancer were higher than the tissue of without cancer,and the rate of p53 gene mutation in telomerase activity were obviously higher than the group of without cancer.This shows the p53 gene mutation can loss of function of suppressing cancer and prompt telomerase activity and cause the cardiac cancer.展开更多
A novel high-entropy material,(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)was successfully synthesized by the solid state reaction method and spark plasma sintering,and investigated as a promising thermal ...A novel high-entropy material,(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)was successfully synthesized by the solid state reaction method and spark plasma sintering,and investigated as a promising thermal barrier coating material.Rare-earth elements were distributed homogeneously in the pyrochlore structure.It was found that the prepared high-entropy ceramic maintains pyrochlore structure at the temperature up to 1600℃,and it possesses a similar thermal expansion coefficient(10.2×10^(−6)K^(−1) at 25-900℃)to that of YSZ,low thermal conductivity(<0.9 W m^(-1)K^(−1) at 100-1000℃)and good CMAS resistance(infiltration depth is 22μm after annealed at 1300℃for 24 h).The corrosion process was investigated,and RE elements distributing homogeneously in(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)show different diffusion rates in CMAS.RE^(3+) with a larger radius(closer to Ca^(2+))is easier to react with CMAS to form an apatite phase.展开更多
Previous studies demonstrated that superoxide could initiate and amplify LDH-catalyzed hydrogen peroxide production in aqueous phase,but its physiological relevance is unknown.Here we showed that LDHA and LDHB both ex...Previous studies demonstrated that superoxide could initiate and amplify LDH-catalyzed hydrogen peroxide production in aqueous phase,but its physiological relevance is unknown.Here we showed that LDHA and LDHB both exhibited hydrogen peroxide-producing activity,which was significantly enhanced by the superoxide generated from the isolated mitochondria from HeLa cells and patients'cholangiocarcinoma specimen.After LDHA or LDHB were knocked out,hydrogen peroxide produced by Hela or 4T1 cancer cells were significantly reduced.Re-expression of LDHA in LDHA-knockout HeLa cells partially restored hydrogen peroxide production.In HeLa and 4T1 cells,LDHA or LDHB knockout or LDH inhibitor FX11 significantly decreased ROS induction by modulators of the mitochondrial electron transfer chain(antimycin,oligomycin,rotenone),hypoxia,and pharmacological ROS inducers piperlogumine(PL)and phenethyl isothiocyanate(PEITC).Moreover,the tumors formed by LDHA or LDHB knockout HeLa or 4T1 cells exhibited a significantly less oxidative state than those formed by control cells.Collectively,we provide a mechanistic understanding of a link between LDH and cellular hydrogen peroxide production or oxidative stress in cancer cells in vitro and in vivo.展开更多
The hadal zone,mostly comprising of deep trenches and constituting of the deepest part of the world’s oceans,represents the least explored habitat but one of the last frontiers on our planet.The present scientific un...The hadal zone,mostly comprising of deep trenches and constituting of the deepest part of the world’s oceans,represents the least explored habitat but one of the last frontiers on our planet.The present scientific understanding of the hadal environment is still relatively rudimentary,particularly in comparison with that of shallower marine environments.In the last 30 years,continuous efforts have been launched in deepening our knowledge regarding the ecology of the hadal trench.However,the geological and environmental processes that potentially affect the sedimentary,geochemical and biological processes in hadal trenches have received less attention.Here,we review recent advances in the geology,biology,and environment of hadal trenches and offer a perspective of the hadal science involved therein.For the first time,we release highdefinition images taken by a new full-ocean-depth manned submersible Fendouzhe that reveal novel species with an unexpectedly high density,outcrops of mantle and basaltic rocks,and anthropogenic pollutants at the deepest point of the world’s ocean.We advocate that the hydration of the hadal lithosphere is a driving force that influences a variety of sedimentary,geochemical,and biological processes in the hadal trench.Hadal lithosphere might host the Earth’s deepest subsurface microbial ecosystem.Future research,combined with technological advances and international cooperation,should focus on establishing the intrinsic linkage of the geology,biology,and environment of the hadal trenches.展开更多
基金supported by the Guiding Science and Technology Planning Project of Daqing(Grant No.zd-2021-36)Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province,China(Grant No.LBH-Z21084)Natural Science Foundation of Heilongjiang Province(Grant No.LH 2022E019).
文摘The oil and gas potential of the Yan'an Formation in the Ordos Basin has yet to be fully tapped. In this study, the pore structure, mobile fluid saturation, and water flooding micro-mechanism of the Yan'an Formation sandstone are systematically studied through the application of a series of rock physics and fluid experiments. The results show that there is a good positive correlation between porosity and permeability, and the reservoirs are divided into types Ⅰ, Ⅱ, and Ⅲ. Mercury injection tests show that the average pore throat radius of the oil-bearing reservoir ranges from 1 to 7 μm. The displacement pressure of the Yan'an Formation is also relatively low, and it decreases from 0.1 MPa to 0.01 MPa as the rock porosity increases from 11% to 18%. NMR tests show that small (diameter <0.5 μm) and medium pores (diameter ranging from 0.5 to 2.5 μm) are predominant in the reservoir. Different types of reservoirs have different characteristics of relative permeability curve. In addition, when the average oil recovery rate is less than 1 ml/min, the oil displacement efficiency increases faster. However, when the average oil recovery rate is between 1–3.5 ml/min, the oil displacement efficiency is maintained at around 27%–30%. Physical properties of the reservoir, pore-throat structure, experimental pressure difference, and pore volume injected — all have significant effects on oil displacement efficiency. For Type Ⅰ and Type Ⅱ reservoirs, the increase of the pore volume injected has a significant effect on oil displacement efficiency. However, for Type Ⅲ reservoirs, the change of pore volume injected has insignificant effect on oil displacement efficiency. This study provides a reference for the formulation of estimated ultimate recovery (EUR) measures for similar sandstone reservoirs.
基金supported by the National Natural Science Foundation of China (Grant No.12072331)the Science Challenge Project (Grant No.TZ2018001)+2 种基金the Japan Society for the Promotion of Science (Grant Nos.17H04820 and 21H01677)the Foundation of the United Laboratory of High-Pressure Physics and Earthquake Scienceperformed under the approval of the Photon Factory Program Advisory Committee (Proposal Nos.2016S2-006 and 2020G680)。
文摘A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process.
基金supported by the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0306)the Special Fund of the Institute of Geophysics,China Earthquake Administration(No.DQJB21B32)the National Natural Science Foundation of China(No.42174069).
文摘Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region.
基金the National Natural Science Foundation of China(Nos.U1939204,and 41774056).
文摘The Hi-CLIMB seismic array is located in the central-western Tibetan Plateau.The H-κ-c method(Li JT et al.,2019)was applied to receiver function data on the HiCLIMB,which corrects the back-azimuthal variations in the arrival times of Ps and crustal multiples caused by crustal anisotropy and dipping interfaces before performing H-κstacking.Compared to the traditional H-κmethod,the H-κstacking results after harmonic corrections showed considerable improvements,including greatly reduced errors,significantly less scattered H(crustal thickness)andκ(crustal v_(P)/v_(S)ratio)values,and clearer patterns of H andκin different Tibetan blocks.This demonstrates that the H-κ-c method works well even for regions with complex crustal structures,such as the Tibetan Plateau,when there are helpful references from nearby stations or other constraints.The variation in crustal thickness agrees with previous studies but tends to be relatively shallower beneath most of the plateau.Two regions with particularly high crustal v_(P)/v_(S)were observed,namely,one in the northern Himalaya block and beneath the YarlungZangbo suture,and the other in the Qiangtang block.Their correlation with mid-crust low S velocities from previous studies suggests the possible presence of fluid or partial melt in the two regions,which may have implications for the crustal flow model.In contrast,the Lhasa block had relatively lower crustal v_(P)/v_(S)and relatively higher crustal S velocity within the plateau,which is interpreted to be mechanically stronger than the Himalaya and Qiangtang blocks,and without mid-crust partial melt.
基金supportedby the Special Fund of the Instituteof Geophysics,China Earthquake Administration(Grant No.DQJB21B32)the National Natural Science Foundation of China(No.U1939204).
文摘The Chinese mainland is subject to complicated plate interactions that give rise to its complex structure and tectonics. While several seismic velocity models have been developed for the Chinese mainland, apparent discrepancies exist and, so far, little effort has been made to evaluate their reliability and consistency. Such evaluations are important not only for the application and interpretation of model results but also for future model improvement. To address this problem, here we compare five published shear-wave velocity models with a focus on model consistency. The five models were derived from different datasets and methods (i.e., body waves, surface waves from earthquakes, surface waves from noise interferometry, and full waves) and interpolated into uniform horizontal grids (0.5° × 0.5°) with vertical sampling points at 5 km, 10 km, and then 20 km intervals to a depth of 160 km below the surface, from which we constructed an averaged model (AM) as a common reference for comparative study. We compare both the absolute velocity values and perturbation patterns of these models. Our comparisons show that the models have large (> 4%) differences in absolute values, and these differences are independent of data coverage and model resolution. The perturbation patterns of the models also show large differences, although some of the models show a high degree of consistency within certain depth ranges. The observed inconsistencies may reflect limited model resolution but, more importantly, systematic differences in the datasets and methods employed. Thus, despite several seismic models being published for this region, there is significant room for improvement. In particular, the inconsistencies in both data and methodologies need to be resolved in future research. Finally, we constructed a merged model (ChinaM-S1.0) that incorporates the more robust features of the five published models. As the existing models are constrained by different datasets and methods, the merged model serves as a new type of reference model that incorporates the common features from the joint datasets and methods for the shear-wave velocity structure of the Chinese mainland lithosphere.
基金funded by grants from the National Key Research and Development Program of China(Grant Number 2021YFA1500400)Science and Technology Department of Jilin Province(Grant Number 20200201386JC)+1 种基金Science and Technology Department of Jjilin Province(Grant Number 20190701037GH)Education Department of Jilin Province(Grant Number JJKH20200948K).
文摘Exosomes are extracellular vesicles with a 30–150 nm diameter originating from endosomes.In recent years,scientists have regarded exosomes as an ideal small molecule carrier for the targeted treatment of Alzheimer’s disease(AD)across the blood-brain barrier due to their nanoscale size and low immunogenicity.A large amount of evidence shows that exosomes are rich in biomarkers,and it has been found that the changes in biomarker content in blood,cerebrospinal fluid,and urine are often associated with the onset of AD patients.In this paper,some recent advances in the use of exosomes in the treatment of AD are reviewed,and various exosome markers and some latest detection methods are summarized to provide some evidence for the detection or treatment of AD by exosomes.
文摘W/Cu Functionally Graded Materials (FGM) was designed not only for reducing the thermal stress caused by the mismatch of thermal expansion coefficients, but also for combining the features of W, Mo - high plasma-erosion resistance and the advantages of Cu - high heat conductivity and ductility. Four different fabrication processes for W/Cu or Mo/Cu, including hot-pressing, Cu infiltration of sintered porosity-graded W skeleton, spark plasma sintering and plasma spraying, were investigated and compared. It was foundthat the hot-pressing process is difficult to keep the designed composition gradient, while the other three processes are successful in making W/Cu or Mo/Cu FGM. Meanwhile, microstructures and composition gradients are analyzed with SEM and EDAX.
基金supported jointly by the National Natural Science Foundation of China (Nos. U1939204, 41774056, and 41704046)the Fundamental Research Funds for the Central Universities (No. 2042020kf0010)
文摘The complex tectonic background of East Asia makes it an ideal region for investigating the evolution of the continental lithosphere,for which high-resolution lithospheric structural models are essential.In this study,we measured Rayleigh-wave phase-velocity dispersion curves at periods of 10-120 s and group velocity dispersion curves at periods of 10-140 s using event records from more than 1,000 seismic stations in and around China.By jointly inverting new and previously published dispersion data from ambient noise and earthquakes,we developed a high-resolution shear-wave velocity model down to a depth of~300 km beneath East Asia.Our model revealed heterogeneous lithospheric structures beneath East Asia,and allowed us to investigate the velocity structure of the entire lithosphere.We also derived crustal and lithospheric thickness models from the three-dimensional(3D)shear-wave model,revealing strong spatial heterogeneity and a general thinning trend of lithospheric thickness from west to east across the study region.Overall,our models reveal important lithospheric features beneath East Asia and provide a valuable baseline dataset for understanding continental-scale dynamics and evolution.
基金This work was supported by grants from the Beijing Committee of Science and Technology(Grant No.Z181100001718162)the Fundamental Research Funds for the Central Universities(Grant No.3332020071)+2 种基金the CAMS Innovation Fund for Medical Sciences(Grant No.2018-I2M-1-002)the Capital’s Funds for Health Improvement and Research(Grant No.2018-4-4089)the Beijing Municipal Natural Science Foundation(Grant No.7182178).
文摘Objective:Acute myeloid leukemia(AML)is primarily a malignant disorder affecting the elderly.We aimed to compare the outcomes of different treatment patterns in elderly AML patients and to propose a prognostic scoring system that could predict survival and aid therapeutic decisions.Methods:Patients aged≥60 years who had been diagnosed with AML at 7 hospitals in China were enrolled(n=228).Treatment patterns included standard chemotherapy,low intensity therapy,and best supportive care(BSC).Results:The early mortality rates were 31%,6.8%,and 6.3%for the BSC,low intensity therapy,and standard chemotherapy groups,respectively.The complete remission rate of the standard chemotherapy group was higher than that of the low intensity therapy group.The median overall survival(OS)was 561 days and 222 days for the standard chemotherapy and low intensity therapy groups,respectively,and were both longer than that of the BSC group(86 days).Based on multivariate analyses,we defined a prognostic scoring system that enabled classification of patients into 3 risk groups,in an attempt to predict the OS of patients receiving chemotherapies and low intensity therapies.Low and intermediate risk patients benefited more from standard chemotherapies than from low intensity therapies.However,the median OS was comparable between standard chemotherapies and low intensity therapies in high risk patients.Conclusions:Our prognostic scoring system could predict survival and help select appropriate therapies for elderly AML patients.Standard chemotherapy is important for elderly AML patients,particularly for those categorized into low and intermediate risk groups.
文摘The distribution transformer is the mainstay of the power system.Its internal temperature study is desirable for its safe operation in the power system.The purpose of the present study is to determine direct comprehensive thermal distribution in the distribution transformers for different loading conditions.To achieve this goal,the temperature distribution in the oil,core,and windings are studied at each loading.An experimental study is performed with a 10/0.38 kV,10 kVA oil–immersed transformer equipped with forty–two PT100 sensors(PTs)for temperature measurement installed inside during its manufacturing process.All possible locations for the hottest spot temperature(HST)are considered that made by finite element analysis(FEA)simulation and losses calculations.A resistive load is made to achieve 80%to 120%loading of the test transformer for this experiment.Working temperature is measured in each part of the transformer at all provided loading conditions.It is observed that temperature varies with loading throughout the transformer,and a detailed map of temperature is obtained in the whole test transformer.From these results,the HST stays in the critical section of the primary winding at all loading conditions.This work is helpful to understand the complete internal temperature layout and the location of the HST in distribution transformers.
基金This work was supported by National Natural Science Foundation of China(No.61772243)Jiangsu Provincial Key Research and Development Program(BE2018108)Six talent peak high level talent plan projects of Jiangsu Province(XYDXX-115).
文摘Driven by the continuous penetration of high data rate services and applications,a large amount of unregulated visible light spectrum is used for communication to fully meet the needs of 6th generation(6G)mobile technologies.Visible light communication(VLC)faces many challenges as a solution that complements existing radio frequency(RF)networks.This paper studies the optimal configuration of LEDs in indoor environments under the constraints of illumination and quality of experience(QoE).Based on the Voronoi tessellation(VT)and centroidal Voronoi tessellation(CVT)theory,combined with the Lloyd’s algorithm,we propose two approaches for optimizing LED deployments to meet the illumination and QoE requirements of all users.Focusing on(i)the minimization of the number of LEDs to be installed in order to meet illumination and average QoE constraints,and(ii)the maximization of the average QoE of users to be served with a fixed number of LEDs.Monte Carlo simulations are carried out for different user distribution compared with hexagonal,square and VT deployment.The simulation results illustrate that under the same conditions,the proposed deployment approach can provide less LEDs and achieve better QoE performance.
基金the National Natural Science Foundation of China(NSFC,Grant Nos.12073002 and 11721303)the High-performance Computing Platform of Peking University。
文摘We study the vertical distribution of the highly inclined galaxies from the Continuum Halos in Nearby Galaxies—an EVLA Survey(CHANG-ES).We explore the feasibility of photometrically deriving the HⅠdisk scale heights from the moment-0 images of the relatively edge-on galaxies with inclination>80°,by quantifying the systematic broadening effects and thus deriving correction equations for direct measurements.The corrected HⅠdisk scale heights of the relatively edge-on galaxies from the CHANG-ES sample show trends consistent with the quasiequilibrium model of the vertical structure of gas disks.The procedure provides a convenient way to derive the scale heights and can easily be applied to statistical samples in the future.
文摘Objective:To study the relationship of the telomerase activity and the p53 gene mutation in cardiac cancer. Methods:Telomerase activity and the p53 gene mutation were detected in 46 case of cardiac cancer,peri-cancerous and 30 case of normal mucosa by TRAP-ELISA and PCR-SSCP.Results:The rate of expression of telomerase activity in cardiac cancer,peri-cancerous and normal mucosa were 82.61%(38/46),43.48%(20/46)and 13.33%(4/30)respectively.The rate of Exon5→8 of p53 gene mutation were 39.13%(18/46),4.35%(2/46)and 0.00%respectively.There was significant differ- ence between group cancer and without cancer(P<0.01).Mean of A value of telomerase is 1.89±0.41 in cancer group and were 1.49±0.43,0.54±0.45 respectively in peri-canvcerous and normal mucosa,there were significant differences in cancer group and group of without cancer(P<0.05).The rate of p53 gene mutations in group of expression of telomerase activity was 44.74%(17/38),and 12.50%(1/8)in without expression of telomerase activity.There were significant differences between the two groups.Conclusion:The rate of expression of telomerase activity and mean of A value of telomerase in cardiac cancer were obviously higher than without cancer,which indicating telomerase activity was closely related with the occurrence of cardiac cancer.P53 gene mutation in cardiac cancer were higher than the tissue of without cancer,and the rate of p53 gene mutation in telomerase activity were obviously higher than the group of without cancer.This shows the p53 gene mutation can loss of function of suppressing cancer and prompt telomerase activity and cause the cardiac cancer.
基金supported by the National Key Research and Development Program of China(No.2016YFB070204)the National Natural Science Foundation of China(Nos.52072381 and U1904217)。
文摘A novel high-entropy material,(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)was successfully synthesized by the solid state reaction method and spark plasma sintering,and investigated as a promising thermal barrier coating material.Rare-earth elements were distributed homogeneously in the pyrochlore structure.It was found that the prepared high-entropy ceramic maintains pyrochlore structure at the temperature up to 1600℃,and it possesses a similar thermal expansion coefficient(10.2×10^(−6)K^(−1) at 25-900℃)to that of YSZ,low thermal conductivity(<0.9 W m^(-1)K^(−1) at 100-1000℃)and good CMAS resistance(infiltration depth is 22μm after annealed at 1300℃for 24 h).The corrosion process was investigated,and RE elements distributing homogeneously in(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)show different diffusion rates in CMAS.RE^(3+) with a larger radius(closer to Ca^(2+))is easier to react with CMAS to form an apatite phase.
基金This work has been supported in part by the China National 973 project(2013CB911303)China Natural Sciences Foundation projects(81470126)+4 种基金a key project(2018C03009)funded by Zhejiang Provincial Department of Sciences and Technologiesthe Fundamental Research Funds for the Central Universities(2017XZZX001-012019FZJD009)National Ministry of Education,China,to X.H.,and Zhejiang Provincial Natural Science Foundation of China(LY17H160036)the Fundamental Research Funds for the Central Universities(2017FZA7010)China Natural Sciences Foundation project(81301707),to H.W.
文摘Previous studies demonstrated that superoxide could initiate and amplify LDH-catalyzed hydrogen peroxide production in aqueous phase,but its physiological relevance is unknown.Here we showed that LDHA and LDHB both exhibited hydrogen peroxide-producing activity,which was significantly enhanced by the superoxide generated from the isolated mitochondria from HeLa cells and patients'cholangiocarcinoma specimen.After LDHA or LDHB were knocked out,hydrogen peroxide produced by Hela or 4T1 cancer cells were significantly reduced.Re-expression of LDHA in LDHA-knockout HeLa cells partially restored hydrogen peroxide production.In HeLa and 4T1 cells,LDHA or LDHB knockout or LDH inhibitor FX11 significantly decreased ROS induction by modulators of the mitochondrial electron transfer chain(antimycin,oligomycin,rotenone),hypoxia,and pharmacological ROS inducers piperlogumine(PL)and phenethyl isothiocyanate(PEITC).Moreover,the tumors formed by LDHA or LDHB knockout HeLa or 4T1 cells exhibited a significantly less oxidative state than those formed by control cells.Collectively,we provide a mechanistic understanding of a link between LDH and cellular hydrogen peroxide production or oxidative stress in cancer cells in vitro and in vivo.
基金This work was financially supported by the National Key Research and Development Program of China(grant nos.2016YFC0300503,2016YFC0300600,2016YFC0304900).
文摘The hadal zone,mostly comprising of deep trenches and constituting of the deepest part of the world’s oceans,represents the least explored habitat but one of the last frontiers on our planet.The present scientific understanding of the hadal environment is still relatively rudimentary,particularly in comparison with that of shallower marine environments.In the last 30 years,continuous efforts have been launched in deepening our knowledge regarding the ecology of the hadal trench.However,the geological and environmental processes that potentially affect the sedimentary,geochemical and biological processes in hadal trenches have received less attention.Here,we review recent advances in the geology,biology,and environment of hadal trenches and offer a perspective of the hadal science involved therein.For the first time,we release highdefinition images taken by a new full-ocean-depth manned submersible Fendouzhe that reveal novel species with an unexpectedly high density,outcrops of mantle and basaltic rocks,and anthropogenic pollutants at the deepest point of the world’s ocean.We advocate that the hydration of the hadal lithosphere is a driving force that influences a variety of sedimentary,geochemical,and biological processes in the hadal trench.Hadal lithosphere might host the Earth’s deepest subsurface microbial ecosystem.Future research,combined with technological advances and international cooperation,should focus on establishing the intrinsic linkage of the geology,biology,and environment of the hadal trenches.
