The Joule-Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with carbon capture and storage(CCS). In this work, a set of apparatus was set up to determin...The Joule-Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with carbon capture and storage(CCS). In this work, a set of apparatus was set up to determine the Joule-Thomson effect of binary mixtures(CO_(2)+ H_(2)). The accuracy of the apparatus was verified by comparing with the experimental data of carbon dioxide. The Joule-Thomson coefficients(μ_(JT)) for(CO_(2)+ H_(2)) binary mixtures with mole fractions of carbon dioxide(x_(CO_(2))= 0.1, 0.26, 0.5,0.86, 0.94) along six isotherms at various pressures were measured. Five equations of state EOSs(PR,SRK, PR, BWR and GERG-2008 equation) were used to calculate the μ_(JT)for both pure systems and binary systems, among which the GERG-2008 predicted best with a wide range of pressure and temperature.Moreover, the Joule-Thomson inversion curves(JTIC) were calculated with five equations of state. A comparison was made between experimental data and predicted data for the inversion curve of CO_(2). The investigated EOSs show a similar prediction of the low-temperature branch of the JTIC for both pure and binary systems, except for the BWRS equation of state. Among all the equations, SRK has the most similar result to GERG-2008 for predicting JTIC.展开更多
Once China’s Tianwen-1 Mars probe arrived in a Mars orbit after a seven-month flight in the deep cold space environment,it would be urgently necessary to monitor its state and the surrounding environment.To address t...Once China’s Tianwen-1 Mars probe arrived in a Mars orbit after a seven-month flight in the deep cold space environment,it would be urgently necessary to monitor its state and the surrounding environment.To address this issue,we developed a flexible deployable subsystem based on shape memory polymer composites(SMPC-FDS)with a large folding ratio,which incorporates a camera and two temperature telemetry points for monitoring the local state of the Mars orbiter and the deep space environment.Here,we report on the development,testing,and successful application of the SMPC-FDS.Before reaching its Mars remote-sensing orbit,the SMPC-FDS is designed to be in a folded state with high stiffness;after reaching orbit,it is in a deployed state with a large envelope.The transition from the folded state to the deployed state is achieved by electrically heating the shape memory polymer composites(SMPCs);during this process,the camera on the SMPC-FDS can capture the local state of the orbiter from multiple angles.Moreover,temperature telemetry points on the SMPC-FDS provide feedback on the environment temperature and the temperature change of the SMPCs during the energization process.By simulating a Mars on-orbit space environment,the engineering reliability of the SMPC-FDS was comprehensively verified in terms of the material properties,structural dynamic performance,and thermal vacuum deployment feasibility.Since the launch of Tianwen-1 on 23 July 2020,scientific data on the temperature environment around Tianwen-1 has been successfully acquired from the telemetry points on the SMPCFDS,and the local state of the orbiter has been photographed in orbit,showing the national flag of China fixed on the orbiter.展开更多
The vapor–liquid equilibrium(VLE)data of a-pinene+camphene+[abietic acid+palustric acid+neoabietic acid]and a-pinene+longifolene+[abietic acid+palustric acid+neoabietic acid]systems at 313.15 K,333.15 K and 358.15 K ...The vapor–liquid equilibrium(VLE)data of a-pinene+camphene+[abietic acid+palustric acid+neoabietic acid]and a-pinene+longifolene+[abietic acid+palustric acid+neoabietic acid]systems at 313.15 K,333.15 K and 358.15 K were measured by headspace gas chromatography(HSGC).These data was compared with the predictions value by conductor-like screening model for realistic solvation(COSMO-RS).Moreover,the calculated data of COSMO-RS and Non-Random Two-Liquids(NRTL)models showed good agreement with the experimental data.It was found that the three resin acids inhibited the volatility of a-pinene,camphene and longifolene and resulted in the decrease of total pressure.Moreover,HE(HB)contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of a-pinene,camphene and longifolene with the three resin acids.In addition,the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.展开更多
Esophageal cancer usually has a poor prognosis.Given the significant breakthrough with tumor immunotherapy,an increasing number of clinical studies have demonstrated that the combination of radiotherapy and immune che...Esophageal cancer usually has a poor prognosis.Given the significant breakthrough with tumor immunotherapy,an increasing number of clinical studies have demonstrated that the combination of radiotherapy and immune checkpoint inhibitors(ICIs)may have a synergistic effect and good outcome in esophageal cancer.Clinical studies of immunoradiotherapy(iRT)for esophageal cancer have proliferated enormously from 2021 to the present.However,a summary of the efficacy and toxicity of combined therapy to guide esophageal cancer treatment in clinical practice is lacking.For this review,we integrate the latest data to analyze and assess the efficacy and safety of iRT for esophageal cancer.In addition,we discuss better predictive biomarkers,therapeutic options for specific populations,and other challenges to identify directions for future research design.展开更多
Background: Recent obstetrical practice tends to avoid the use of manual uterine fundal pressure (MUFP);however, data showed that MUFP is actually employed. We here attempted 1) to determine the obstetricians’ attitu...Background: Recent obstetrical practice tends to avoid the use of manual uterine fundal pressure (MUFP);however, data showed that MUFP is actually employed. We here attempted 1) to determine the obstetricians’ attitudes towards MUFP via questionnaire, and 2) to examine whether MUFP shortens the 2nd stage of labor, with the latter tested as a pilot study. Methods: A questionnaire-based study was carried out (n = 122) at meetings of Obstetrics on May 5, 2017. Then, we conducted a pilot case-control study from August 23 to September 6, 2020. Participants (n = 29) were divided into two groups;women who did and did not want MUFP;i.e., MUFP (n = 14) vs. (Non-MUFP) group (n = 15). Results: Of 122 doctors, 99.18% (121/122) used MUFP at cesarean section. 95.90% (117/122) of institutions used MUFP in spontaneous delivery. 95.08% (116/122) obstetricians considered MUFP effective and helpful. 85.24% (104/122) considered that MUFP should be employed after station +3. In the case control study, MUFP vs. Non-MUFP group showed the second-stage-duration of 58.5 (50.25 - 71.25) vs. 48 (39 - 59) minutes, without statistical significance (P = 0.101). However, importantly, MUFP, compared with Non-MUFP group, showed a significantly shorter duration from head visible on introitus (apparition) to delivery;i.e., 21.26 ± 7.32 vs. 30.13 ± 10.61 minutes (P = 0.014). Conclusions: MUFP is still used widely and MUFP shortened the duration of head apparition to delivery time. Larger-sample studies are needed to confirm the efficacy and safety of MUFP.展开更多
Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable s...Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.展开更多
This paper focuses on the sensor subset optimization problem in time difference of arrival(TDOA) passive localization scenario. We seek for the best sensor combination by formulating a non-convex optimization problem,...This paper focuses on the sensor subset optimization problem in time difference of arrival(TDOA) passive localization scenario. We seek for the best sensor combination by formulating a non-convex optimization problem, which is to minimize the trace of covariance matrix of localization error under the condition that the number of selected sensors is given. The accuracy metric is described by the localization error covariance matrix of classical closed-form solution, which is introduced to convert the TDOA nonlinear equations into pseudo linear equations. The non-convex optimization problem is relaxed to a standard semi-definite program(SDP) and efficiently solved in a short time. In addition, we extend the sensor selection method to a mixed TDOA and angle of arrival(AOA) localization scenario with the presence of sensor position errors. Simulation results validate that the performance of the proposed sensor selection method is very close to the exhaustive search method.展开更多
Nonlinear dynamic characteristics of a fixed-trim reentry vehicle controlled by an internal moving-mass actuator are analyzed. A traditional dynamic model develops into a five-dimensional nonlinear model using classic...Nonlinear dynamic characteristics of a fixed-trim reentry vehicle controlled by an internal moving-mass actuator are analyzed. A traditional dynamic model develops into a five-dimensional nonlinear model using classic Euler angles and their derivatives as state variables. Based on the nonlinear motion equations, by setting the offset distance of the moving-mass as a variation parameter, the curves of the system's equilibrium points are presented by numerical methods. Then the distributions and approximate analytical solutions of the equilibrium points are obtained by simplifying the model under the condition of small intrinsic angles.The results show that the numbers and values of the equilibrium points are closely connected with the location of the moving-mass.Furthermore, the stabilities of equilibrium points are examined by the Lyapunov's first method and three groups of stable equilibrium points are obtained. Since only one group of the stable equilibrium points is desired, the angular motion of the system may be unstable or stay in an undesired lock-in state when the offset distance of the moving-mass or the attitude disturbance of the vehicle is too large.展开更多
Radiotherapy is one of the most effective treatment methods for various solid tumors.Bidirectional signal transduction between cancer cells and stromal cells within the irradiated microenvironment is important in canc...Radiotherapy is one of the most effective treatment methods for various solid tumors.Bidirectional signal transduction between cancer cells and stromal cells within the irradiated microenvironment is important in cancer development and treatment responsiveness.Exosomes,initially considered as"garbage bins"for unwanted from cells,are now understood to perform a variety of functions in interactions within the tumor microenvironment.Exosome-mediated regulation processes are rebuilt under the irradiation stimuli,because the exosome production,uptake,and contents are markedly modified by irradiation.In turn,irradiation-modified exosomes may modulate the cell response to irradiation through feedback regulation.Here,we review current knowledge and discuss the roles of exosome-mediated interactions between cells under radiotherapy conditions.展开更多
The objective of this study is to investigate the feasibility of using chitosanesodium alginate(CSeSA)based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables.Using tri...The objective of this study is to investigate the feasibility of using chitosanesodium alginate(CSeSA)based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables.Using trimetazidine hydrochloride(TH)as a water-soluble model drug,influence of dissolution medium,the amount of CSeSA,the CS:SA ratio,the type of SA,the type and amount of diluents,on in vitro drug release from CSeSA based matrix tablets were studied.Drug release kinetics and release mechanisms were elucidated.In vitro release experiments were conducted in simulated gastric fluid(SGF)followed by simulated intestinal fluid(SIF).Drug release rate decreased with the increase of CSeSA amount.CS:SA ratio had only slight effect on drug release and no influence of SA type on drug release was found.On the other hand,a large amount of water-soluble diluents could modify drug release profiles.It was found that drug release kinetics showed the best fit to Higuchi equation with Fickian diffusion as the main release mechanism.In conclusion,this study demonstrated that it is possible to design extended-release tablets of watersoluble drugs using CSeSA as the matrix by optimizing formulation components,and provide better understanding about drug release from CSeSA matrix tablets.展开更多
The objective of this study is to develop chitosaneanionic polymers based extendedrelease tablets and test the feasibility of using this system for the sustained release of highly water-soluble drugs with high drug lo...The objective of this study is to develop chitosaneanionic polymers based extendedrelease tablets and test the feasibility of using this system for the sustained release of highly water-soluble drugs with high drug loading.Here,the combination of sodium valproate(VPS)and valproic acid(VPA)were chosen as the model drugs.Anionic polymers studied include xanthan gum(XG),carrageenan(CG),sodium carboxymethyl cellulose(CMC-Na)and sodium alginate(SA).The tablets were prepared by wet granulation method.In vitro drug release was carried out under simulated gastrointestinal condition.Drug release mechanism was studied.Compared with single polymers,chitosaneanionic polymers based system caused a further slowdown of drug release rate.Among them,CS exanthan gum matrix system exhibited the best extended-release behavior and could extend drug release for up to 24 h.Differential scanning calorimetry(DSC)and Fourier transform infrared spectroscopy(FTIR)studies demonstrated that polyelectrolyte complexes(PECs)were formed on the tablet surface,which played an important role on retarding erosion and swelling of the matrix in the later stage.In conclusion,this study demonstrated that it is possible to develop highly water-soluble drugs loaded extendedrelease tablets using chitosaneanionic polymers based system.展开更多
Gas hydrate is regarded as a promising energy owing to the large carbon reserve and high energy density.However,due to the particularity of the formation and the complexity of exploitation process,the commercial explo...Gas hydrate is regarded as a promising energy owing to the large carbon reserve and high energy density.However,due to the particularity of the formation and the complexity of exploitation process,the commercial exploitation of gas hydrate has not been realized.This paper reviews the physical properties of gas hydratebearing sediments and focuses on the geomechanical response during the exploitation.The exploitation of gas hydrate is a strong thermal–hydrological–mechanical–chemical(THMC)coupling process:decomposition of hydrate into water and gas produces multi-physical processes including heat transfer,multi-fluid flow and deformation in the reservoir.These physical processes lead to a potential of geomechanical issues during the production process.Frequent occurrence of sand production is the major limitation of the commercial exploitation of gas hydrate.The potential landslide and subsidence will lead to the cessation of the production and even serious accidents.Preliminary researches have been conducted to investigate the geomechanical properties of gas hydrate-bearing sediments and to assess the wellbore integrity during the exploitation.The physical properties of hydrate have been fully studied,and some models have been established to describe the physical processes during the exploitation of gas hydrate.But the reproduction of actual conditions of hydrate reservoir in the laboratory is still a huge challenge,which will inevitably lead to a bias of experiment.In addition,because of the effect of microscopic mechanisms in porous media,the coupling mechanism of the existing models should be further investigated.Great efforts,however,are still required for a comprehensive understanding of this strong coupling process that is extremely different from the geomechanics involved in the conventional reservoirs.展开更多
Li transient concentration distribution in spherical active material particles can affect the maximum power density and the safe operating regime of the electric vehicles(EVs). On one hand, the quasiexact/exact soluti...Li transient concentration distribution in spherical active material particles can affect the maximum power density and the safe operating regime of the electric vehicles(EVs). On one hand, the quasiexact/exact solution obtained in the time/frequency domain is time-consuming and just as a reference value for approximate solutions;on the other hand, calculation errors and application range of approximate solutions not only rely on approximate algorithms but also on discharge modes. For the purpose to track the transient dynamics for Li solid-phase diffusion in spherical active particles with a tolerable error range and for a wide applicable range, it is necessary to choose optimal approximate algorithms in terms of discharge modes and the nature of active material particles. In this study, approximation methods,such as diffusion length method, polynomial profile approximation method, Padé approximation method,pseudo steady state method, eigenfunction-based Galerkin collocation method, and separation of variables method for solving Li solid-phase diffusion in spherical active particles are compared from calculation fundamentals to algorithm implementation. Furthermore, these approximate solutions are quantitatively compared to the quasi-exact/exact solution in the time/frequency domain under typical discharge modes, i.e., start-up, slow-down, and speed-up. The results obtained from the viewpoint of time-frequency analysis offer a theoretical foundation on how to track Li transient concentration profile in spherical active particles with a high precision and for a wide application range. In turn, optimal solutions of Li solid diffusion equations for spherical active particles can improve the reliability in predicting safe operating regime and estimating maximum power for automotive batteries.展开更多
Poplar is raw material for various panel, paper and fiber products. The 12 sample trees of clone Nanlin-895 from four spacings were destructively harvested after thirteen growing seasons to assess the influence of spa...Poplar is raw material for various panel, paper and fiber products. The 12 sample trees of clone Nanlin-895 from four spacings were destructively harvested after thirteen growing seasons to assess the influence of spacing on radial growth and wood properties. Spacing significantly affected tree-ring width and wood basic density (p < 0.05) but not fiber traits. The highest diameter and wood basic density at breast height (1.3 m) was in 6 m × 6 m and 3 m × 8 m spacings, respectively. However, no significant differences in tree-ring width, wood basic density and fiber traits were observed among the four sampling directions in discs taken at 1.3 m for each spacing. Growth rings from the pith and tree heights had significant effects on wood basic density and fiber anatomical characteristics, highlighting obvious temporal-spatial variations. Pearson correlation analysis showed a significantly negative relationship of tree-ring width to wood basic density, fiber length and fiber width, but a significantly positive relationship to hemicellulose. There was no relationship with cellulose and lignin contents. Based on a comprehensive assessment by the TOPSIS method, the 6 m × 6 m spacing is recommended for producing wood fiber at similar sites in the future.展开更多
Brugada syndrome(BrS)is a complex genetic cardiac ion channel disease that causes a high predisposition to sudden cardiac death.Considering that its heterogeneity in clinical manifestations may result from genetic bac...Brugada syndrome(BrS)is a complex genetic cardiac ion channel disease that causes a high predisposition to sudden cardiac death.Considering that its heterogeneity in clinical manifestations may result from genetic background,the application of patient-specific induced pluripotent stem cell-derived cardiomyocytes(iPSC-CMs)may help to reveal cell phenotype characteristics underlying different genetic variations.Here,to verify and compare the pathogenicity of mutations(SCN5A c.4213G>A and SCN1B c.590C>T)identified from two BrS patients,we generated two novel BrS iPS cell lines that carried missense mutations in SCN5A or SCN1B,compared their structures and electrophysiology,and evaluated the safety of quinidine in patient-specific iPSC-derived CMs.Compared to the control group,BrS-CMs showed a significant reduction in sodium current,prolonged action potential duration,and varying degrees of decreased Vmax,but no structural difference.After applying different concentrations of quinidine,drug-induced cardiotoxicity was not observed within 3-fold unbound effective therapeutic plasma concentration(ETPC).The data presented proved that iPSC-CMs with variants in SCN5A c.4213G>A or SCN1B c.590C>T are able to recapitulate single-cell phenotype features of BrS and respond appropriately to quinidine without increasing incidence of arrhythmic events.展开更多
基金supported by the National Natural Science Foundation of China (21878056)Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology (2019Z002)。
文摘The Joule-Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with carbon capture and storage(CCS). In this work, a set of apparatus was set up to determine the Joule-Thomson effect of binary mixtures(CO_(2)+ H_(2)). The accuracy of the apparatus was verified by comparing with the experimental data of carbon dioxide. The Joule-Thomson coefficients(μ_(JT)) for(CO_(2)+ H_(2)) binary mixtures with mole fractions of carbon dioxide(x_(CO_(2))= 0.1, 0.26, 0.5,0.86, 0.94) along six isotherms at various pressures were measured. Five equations of state EOSs(PR,SRK, PR, BWR and GERG-2008 equation) were used to calculate the μ_(JT)for both pure systems and binary systems, among which the GERG-2008 predicted best with a wide range of pressure and temperature.Moreover, the Joule-Thomson inversion curves(JTIC) were calculated with five equations of state. A comparison was made between experimental data and predicted data for the inversion curve of CO_(2). The investigated EOSs show a similar prediction of the low-temperature branch of the JTIC for both pure and binary systems, except for the BWRS equation of state. Among all the equations, SRK has the most similar result to GERG-2008 for predicting JTIC.
基金supported by the National Natural Science Foundation of China(11632005)the Heilongjiang Touyan Innovation Team Program。
文摘Once China’s Tianwen-1 Mars probe arrived in a Mars orbit after a seven-month flight in the deep cold space environment,it would be urgently necessary to monitor its state and the surrounding environment.To address this issue,we developed a flexible deployable subsystem based on shape memory polymer composites(SMPC-FDS)with a large folding ratio,which incorporates a camera and two temperature telemetry points for monitoring the local state of the Mars orbiter and the deep space environment.Here,we report on the development,testing,and successful application of the SMPC-FDS.Before reaching its Mars remote-sensing orbit,the SMPC-FDS is designed to be in a folded state with high stiffness;after reaching orbit,it is in a deployed state with a large envelope.The transition from the folded state to the deployed state is achieved by electrically heating the shape memory polymer composites(SMPCs);during this process,the camera on the SMPC-FDS can capture the local state of the orbiter from multiple angles.Moreover,temperature telemetry points on the SMPC-FDS provide feedback on the environment temperature and the temperature change of the SMPCs during the energization process.By simulating a Mars on-orbit space environment,the engineering reliability of the SMPC-FDS was comprehensively verified in terms of the material properties,structural dynamic performance,and thermal vacuum deployment feasibility.Since the launch of Tianwen-1 on 23 July 2020,scientific data on the temperature environment around Tianwen-1 has been successfully acquired from the telemetry points on the SMPCFDS,and the local state of the orbiter has been photographed in orbit,showing the national flag of China fixed on the orbiter.
基金support for this work from the National Natural Science Foundation of China(31960294,32160349)Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2017Z005,2020Z005)+1 种基金the Project for Cultivating New Century Academic and Technology Leaders of Nanning City(2020010)the High-Performance Computing Platform of Guangxi University.
文摘The vapor–liquid equilibrium(VLE)data of a-pinene+camphene+[abietic acid+palustric acid+neoabietic acid]and a-pinene+longifolene+[abietic acid+palustric acid+neoabietic acid]systems at 313.15 K,333.15 K and 358.15 K were measured by headspace gas chromatography(HSGC).These data was compared with the predictions value by conductor-like screening model for realistic solvation(COSMO-RS).Moreover,the calculated data of COSMO-RS and Non-Random Two-Liquids(NRTL)models showed good agreement with the experimental data.It was found that the three resin acids inhibited the volatility of a-pinene,camphene and longifolene and resulted in the decrease of total pressure.Moreover,HE(HB)contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of a-pinene,camphene and longifolene with the three resin acids.In addition,the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.
基金supported by National Natural Science Foundation of China(No.82172865)Clinical Research Special Fund of Wu Jieping Medical Foundation(No.320.6750.2021-02-51 and 320.6750.2021-17-13).
文摘Esophageal cancer usually has a poor prognosis.Given the significant breakthrough with tumor immunotherapy,an increasing number of clinical studies have demonstrated that the combination of radiotherapy and immune checkpoint inhibitors(ICIs)may have a synergistic effect and good outcome in esophageal cancer.Clinical studies of immunoradiotherapy(iRT)for esophageal cancer have proliferated enormously from 2021 to the present.However,a summary of the efficacy and toxicity of combined therapy to guide esophageal cancer treatment in clinical practice is lacking.For this review,we integrate the latest data to analyze and assess the efficacy and safety of iRT for esophageal cancer.In addition,we discuss better predictive biomarkers,therapeutic options for specific populations,and other challenges to identify directions for future research design.
基金supported by the Biological Resources Programme,Chinese Academy of Sciences (KFJ-BRP-008-005)Shanghai Science and Technology Development Foundation (21S21901900)+2 种基金the Lingang Laboratory Grant (LG-QS-202206-01)Ministry of Science and Technology of China (2021YFE0111300)National Natural Science Foundation of China (81973513,81573646).
文摘Background: Recent obstetrical practice tends to avoid the use of manual uterine fundal pressure (MUFP);however, data showed that MUFP is actually employed. We here attempted 1) to determine the obstetricians’ attitudes towards MUFP via questionnaire, and 2) to examine whether MUFP shortens the 2nd stage of labor, with the latter tested as a pilot study. Methods: A questionnaire-based study was carried out (n = 122) at meetings of Obstetrics on May 5, 2017. Then, we conducted a pilot case-control study from August 23 to September 6, 2020. Participants (n = 29) were divided into two groups;women who did and did not want MUFP;i.e., MUFP (n = 14) vs. (Non-MUFP) group (n = 15). Results: Of 122 doctors, 99.18% (121/122) used MUFP at cesarean section. 95.90% (117/122) of institutions used MUFP in spontaneous delivery. 95.08% (116/122) obstetricians considered MUFP effective and helpful. 85.24% (104/122) considered that MUFP should be employed after station +3. In the case control study, MUFP vs. Non-MUFP group showed the second-stage-duration of 58.5 (50.25 - 71.25) vs. 48 (39 - 59) minutes, without statistical significance (P = 0.101). However, importantly, MUFP, compared with Non-MUFP group, showed a significantly shorter duration from head visible on introitus (apparition) to delivery;i.e., 21.26 ± 7.32 vs. 30.13 ± 10.61 minutes (P = 0.014). Conclusions: MUFP is still used widely and MUFP shortened the duration of head apparition to delivery time. Larger-sample studies are needed to confirm the efficacy and safety of MUFP.
文摘Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.
基金supported by the National Natural Science Foundation of China under Grant (61631015, 61501354 61471395 and 61501356)the Key Scientific and Technological Innovation Team Plan (2016KCT-01)the Fundamental Research Funds of the Ministry of Education (7215433803 and XJS16063)
文摘This paper focuses on the sensor subset optimization problem in time difference of arrival(TDOA) passive localization scenario. We seek for the best sensor combination by formulating a non-convex optimization problem, which is to minimize the trace of covariance matrix of localization error under the condition that the number of selected sensors is given. The accuracy metric is described by the localization error covariance matrix of classical closed-form solution, which is introduced to convert the TDOA nonlinear equations into pseudo linear equations. The non-convex optimization problem is relaxed to a standard semi-definite program(SDP) and efficiently solved in a short time. In addition, we extend the sensor selection method to a mixed TDOA and angle of arrival(AOA) localization scenario with the presence of sensor position errors. Simulation results validate that the performance of the proposed sensor selection method is very close to the exhaustive search method.
基金supported by the National Natural Science Foundation of China(61350010)
文摘Nonlinear dynamic characteristics of a fixed-trim reentry vehicle controlled by an internal moving-mass actuator are analyzed. A traditional dynamic model develops into a five-dimensional nonlinear model using classic Euler angles and their derivatives as state variables. Based on the nonlinear motion equations, by setting the offset distance of the moving-mass as a variation parameter, the curves of the system's equilibrium points are presented by numerical methods. Then the distributions and approximate analytical solutions of the equilibrium points are obtained by simplifying the model under the condition of small intrinsic angles.The results show that the numbers and values of the equilibrium points are closely connected with the location of the moving-mass.Furthermore, the stabilities of equilibrium points are examined by the Lyapunov's first method and three groups of stable equilibrium points are obtained. Since only one group of the stable equilibrium points is desired, the angular motion of the system may be unstable or stay in an undesired lock-in state when the offset distance of the moving-mass or the attitude disturbance of the vehicle is too large.
基金supported by the National Natural Science Foundation of China(Grant Nos.81672690,81772900,81872196,and 81972541)the Department of Science and Technology of Sichuan Province(Grant No.2020ZYD033)。
文摘Radiotherapy is one of the most effective treatment methods for various solid tumors.Bidirectional signal transduction between cancer cells and stromal cells within the irradiated microenvironment is important in cancer development and treatment responsiveness.Exosomes,initially considered as"garbage bins"for unwanted from cells,are now understood to perform a variety of functions in interactions within the tumor microenvironment.Exosome-mediated regulation processes are rebuilt under the irradiation stimuli,because the exosome production,uptake,and contents are markedly modified by irradiation.In turn,irradiation-modified exosomes may modulate the cell response to irradiation through feedback regulation.Here,we review current knowledge and discuss the roles of exosome-mediated interactions between cells under radiotherapy conditions.
基金supported by Liaoning Institutions excellent talents support plan(No.LR2013047).
文摘The objective of this study is to investigate the feasibility of using chitosanesodium alginate(CSeSA)based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables.Using trimetazidine hydrochloride(TH)as a water-soluble model drug,influence of dissolution medium,the amount of CSeSA,the CS:SA ratio,the type of SA,the type and amount of diluents,on in vitro drug release from CSeSA based matrix tablets were studied.Drug release kinetics and release mechanisms were elucidated.In vitro release experiments were conducted in simulated gastric fluid(SGF)followed by simulated intestinal fluid(SIF).Drug release rate decreased with the increase of CSeSA amount.CS:SA ratio had only slight effect on drug release and no influence of SA type on drug release was found.On the other hand,a large amount of water-soluble diluents could modify drug release profiles.It was found that drug release kinetics showed the best fit to Higuchi equation with Fickian diffusion as the main release mechanism.In conclusion,this study demonstrated that it is possible to design extended-release tablets of watersoluble drugs using CSeSA as the matrix by optimizing formulation components,and provide better understanding about drug release from CSeSA matrix tablets.
文摘The objective of this study is to develop chitosaneanionic polymers based extendedrelease tablets and test the feasibility of using this system for the sustained release of highly water-soluble drugs with high drug loading.Here,the combination of sodium valproate(VPS)and valproic acid(VPA)were chosen as the model drugs.Anionic polymers studied include xanthan gum(XG),carrageenan(CG),sodium carboxymethyl cellulose(CMC-Na)and sodium alginate(SA).The tablets were prepared by wet granulation method.In vitro drug release was carried out under simulated gastrointestinal condition.Drug release mechanism was studied.Compared with single polymers,chitosaneanionic polymers based system caused a further slowdown of drug release rate.Among them,CS exanthan gum matrix system exhibited the best extended-release behavior and could extend drug release for up to 24 h.Differential scanning calorimetry(DSC)and Fourier transform infrared spectroscopy(FTIR)studies demonstrated that polyelectrolyte complexes(PECs)were formed on the tablet surface,which played an important role on retarding erosion and swelling of the matrix in the later stage.In conclusion,this study demonstrated that it is possible to develop highly water-soluble drugs loaded extendedrelease tablets using chitosaneanionic polymers based system.
基金Supported by the National Natural Science Foundation of China(51809275)the Science Foundation of China University of Petroleum,Beijing(2462018BJC002)
文摘Gas hydrate is regarded as a promising energy owing to the large carbon reserve and high energy density.However,due to the particularity of the formation and the complexity of exploitation process,the commercial exploitation of gas hydrate has not been realized.This paper reviews the physical properties of gas hydratebearing sediments and focuses on the geomechanical response during the exploitation.The exploitation of gas hydrate is a strong thermal–hydrological–mechanical–chemical(THMC)coupling process:decomposition of hydrate into water and gas produces multi-physical processes including heat transfer,multi-fluid flow and deformation in the reservoir.These physical processes lead to a potential of geomechanical issues during the production process.Frequent occurrence of sand production is the major limitation of the commercial exploitation of gas hydrate.The potential landslide and subsidence will lead to the cessation of the production and even serious accidents.Preliminary researches have been conducted to investigate the geomechanical properties of gas hydrate-bearing sediments and to assess the wellbore integrity during the exploitation.The physical properties of hydrate have been fully studied,and some models have been established to describe the physical processes during the exploitation of gas hydrate.But the reproduction of actual conditions of hydrate reservoir in the laboratory is still a huge challenge,which will inevitably lead to a bias of experiment.In addition,because of the effect of microscopic mechanisms in porous media,the coupling mechanism of the existing models should be further investigated.Great efforts,however,are still required for a comprehensive understanding of this strong coupling process that is extremely different from the geomechanics involved in the conventional reservoirs.
基金the financial support from the National Science Foundation of China(22078190 and 12002196)the National Key Research and Development Program of China(2020YFB1505802)。
文摘Li transient concentration distribution in spherical active material particles can affect the maximum power density and the safe operating regime of the electric vehicles(EVs). On one hand, the quasiexact/exact solution obtained in the time/frequency domain is time-consuming and just as a reference value for approximate solutions;on the other hand, calculation errors and application range of approximate solutions not only rely on approximate algorithms but also on discharge modes. For the purpose to track the transient dynamics for Li solid-phase diffusion in spherical active particles with a tolerable error range and for a wide applicable range, it is necessary to choose optimal approximate algorithms in terms of discharge modes and the nature of active material particles. In this study, approximation methods,such as diffusion length method, polynomial profile approximation method, Padé approximation method,pseudo steady state method, eigenfunction-based Galerkin collocation method, and separation of variables method for solving Li solid-phase diffusion in spherical active particles are compared from calculation fundamentals to algorithm implementation. Furthermore, these approximate solutions are quantitatively compared to the quasi-exact/exact solution in the time/frequency domain under typical discharge modes, i.e., start-up, slow-down, and speed-up. The results obtained from the viewpoint of time-frequency analysis offer a theoretical foundation on how to track Li transient concentration profile in spherical active particles with a high precision and for a wide application range. In turn, optimal solutions of Li solid diffusion equations for spherical active particles can improve the reliability in predicting safe operating regime and estimating maximum power for automotive batteries.
基金The work was supported by the National Key Research and Development Program of China(Grant Number 2016YFD0600402).
文摘Poplar is raw material for various panel, paper and fiber products. The 12 sample trees of clone Nanlin-895 from four spacings were destructively harvested after thirteen growing seasons to assess the influence of spacing on radial growth and wood properties. Spacing significantly affected tree-ring width and wood basic density (p < 0.05) but not fiber traits. The highest diameter and wood basic density at breast height (1.3 m) was in 6 m × 6 m and 3 m × 8 m spacings, respectively. However, no significant differences in tree-ring width, wood basic density and fiber traits were observed among the four sampling directions in discs taken at 1.3 m for each spacing. Growth rings from the pith and tree heights had significant effects on wood basic density and fiber anatomical characteristics, highlighting obvious temporal-spatial variations. Pearson correlation analysis showed a significantly negative relationship of tree-ring width to wood basic density, fiber length and fiber width, but a significantly positive relationship to hemicellulose. There was no relationship with cellulose and lignin contents. Based on a comprehensive assessment by the TOPSIS method, the 6 m × 6 m spacing is recommended for producing wood fiber at similar sites in the future.
基金supported by the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20160134 to LW and BK20191071 to CC)National Natural and Science Foundation of China(Grant No.81900295 to CC)Special Foundation for Clinical Science and Technology of Jiangsu Province(Grant No.BE2017754 to HWC).
文摘Brugada syndrome(BrS)is a complex genetic cardiac ion channel disease that causes a high predisposition to sudden cardiac death.Considering that its heterogeneity in clinical manifestations may result from genetic background,the application of patient-specific induced pluripotent stem cell-derived cardiomyocytes(iPSC-CMs)may help to reveal cell phenotype characteristics underlying different genetic variations.Here,to verify and compare the pathogenicity of mutations(SCN5A c.4213G>A and SCN1B c.590C>T)identified from two BrS patients,we generated two novel BrS iPS cell lines that carried missense mutations in SCN5A or SCN1B,compared their structures and electrophysiology,and evaluated the safety of quinidine in patient-specific iPSC-derived CMs.Compared to the control group,BrS-CMs showed a significant reduction in sodium current,prolonged action potential duration,and varying degrees of decreased Vmax,but no structural difference.After applying different concentrations of quinidine,drug-induced cardiotoxicity was not observed within 3-fold unbound effective therapeutic plasma concentration(ETPC).The data presented proved that iPSC-CMs with variants in SCN5A c.4213G>A or SCN1B c.590C>T are able to recapitulate single-cell phenotype features of BrS and respond appropriately to quinidine without increasing incidence of arrhythmic events.
