Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background,an infrared small targe...Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background,an infrared small target detection method based on the tensor nuclear norm and direction residual weighting was proposed.Based on converting the infrared image into an infrared patch tensor model,from the perspective of the low-rank nature of the background tensor,and taking advantage of the difference in contrast between the background and the target in different directions,we designed a double-neighborhood local contrast based on direction residual weighting method(DNLCDRW)combined with the partial sum of tensor nuclear norm(PSTNN)to achieve effective background suppression and recovery of infrared small targets.Experiments show that the algorithm is effective in suppressing the background and improving the detection ability of the target.展开更多
The low field nuclear magnetic resonance (NMR), as a nondestructive and noninvasive technique, was employed to investigate the water distribution and content in cement paste with different water-to-cement ratio (w/c r...The low field nuclear magnetic resonance (NMR), as a nondestructive and noninvasive technique, was employed to investigate the water distribution and content in cement paste with different water-to-cement ratio (w/c ratio) during early and later hydration stages. From the water distribution spectrum deduced from relaxation time distribution in paste, it is suggested that the water fills in the capillary pores at initial period, and then diffuses to the mesopores and gel pores in hydration products with the hydration proceeding. The decrease of peak area in water distribution spectrum reflects the transformation from physically bound water to chemically bound water. In addition, based on the connection between relaxation time and pore size, the relative content changes of water in various states and constrained in different types of pores were also measured. The results demonstrate that it is influenced by the formation of pore system and the original water-to-cement ratio in the paste. Consequently, the relative content of capillary water is dropped to less than 2% in the paste with low w/c ratio of 0.3 when being hydrated for 1 d, while the contents are still 16% and 36% in the pastes with w/c ratios of 0.4 and 0.5, respectively.展开更多
Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.H...Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.However,with respect to its capacity in expanding macroscopic sweep volume under varying heterogeneities,the related results appear inadequate.In this research,three cores with different heterogeneities were used and flooded by the joint water and CO_(2) WAG,then the effects of heterogeneity on oil recovery were determined.More importantly,the cores after CO_(2) WAG injection were investigated using the nuclear magnetic resonance(NMR)technique for remaining oil distribution research,which could help us to understand the capacity of CO_(2) WAG in enlarging sweep volume at different heterogeneities.The results show that the presence of heterogeneity may largely weaken the effectiveness of water flooding,the more severe the heterogeneity,the worse the water flooding.The WAG injection of CO_(2) performs well in EOR after water flooding for all the cores with different heterogeneities;however,it could barely form a complete or full sweep throughout the low-permeability region,and un-swept bypassed regions remain.The homogeneous core is better developed by the injection of the joint water and CO_(2) WAG than the heterogeneous and fractured cases.展开更多
Modal analysis and seismic response analysis were carried out for the equatorial diagnostic port plug of international thermonuclear experimental reactor (ITER). The aim of the theoretical analysis is to verify struct...Modal analysis and seismic response analysis were carried out for the equatorial diagnostic port plug of international thermonuclear experimental reactor (ITER). The aim of the theoretical analysis is to verify structural strength and reliability of the device. The working condition includes one-dimensional seismic wave and two-dimensional seismic wave. Modal analysis of the device shows that primary vibration is inclined to occur in low-order modes. The horizontal (X-direction, Y-direction) maximum vibration appears at the first and the fourth eigen modes, with the natural frequency of 70.59 and 215.88 Hz respectively, and the vertical (Z-direction) primary vibration appears at the second eigen mode with the natural frequency of 82.85 Hz. According to the results of the finite element analysis (FEA) program, the weak portions of the device are distributed in the joint of port body with blanket shielding module (BSM) and inner side wall of ribbed plate for lifting flange, the maximum von Mises stress is 14.8 MPa with the Y-direction seismic wave. In accordance with the design criteria, the destructive effect is far below the failure boundary, and the structural reliability of the equatorial diagnostic port plug can meet the requirements of the design specifications.展开更多
The microscopic response characteristics of nuclear magnetic resonance(NMR) are widely used for characterizing complex pore structures of rocks. Due to the prohibitive NMR experiment cost, numerical simulation was emp...The microscopic response characteristics of nuclear magnetic resonance(NMR) are widely used for characterizing complex pore structures of rocks. Due to the prohibitive NMR experiment cost, numerical simulation was employed as an alternative approach to verify some theoretical aspects of NMR responses. Firstly, the basic principles of pore-scale NMR simulation based on random-walk method(RWM) were introduced. The RWM-simulated results were benchmarked with the analytical results for an ideal spherical pore model. Then, the effects of two numerical parameters, namely diffusion radius and walk numbers, were studied on the simulation accuracy. The simulation method is then applied to various pore models with different pore sizes and pore shapes filled with different fluids to study the microscopic NMR response characteristics. The numerical experiments are useful for understanding and interpreting NMR measurements and the simulation code provides a numerical tool to perform pixel-based digital rock analysis.展开更多
As synthetic aperture radar（SAR） has been widely used nearly in every field, SAR image de-noising became a very important research field. A new SAR image de-noising method based on texture strength and weighted nucl...As synthetic aperture radar（SAR） has been widely used nearly in every field, SAR image de-noising became a very important research field. A new SAR image de-noising method based on texture strength and weighted nuclear norm minimization（WNNM） is proposed. To implement blind de-noising, the accurate estimation of noise variance is very important. So far, it is still a challenge to estimate SAR image noise level accurately because of the rich texture. Principal component analysis（PCA） and the low rank patches selected by image texture strength are used to estimate the noise level. With the help of noise level, WNNM can be expected to SAR image de-noising. Experimental results show that the proposed method outperforms many excellent de-noising algorithms such as Bayes least squares-Gaussian scale mixtures（BLS-GSM） method, non-local means（NLM） filtering in terms of both quantitative measure and visual perception quality.展开更多
This paper introduces a nuclear calamity evaluation expert system which is applied to comprehensive evaluation of damage effects of nuclear calamities. It contains hardware environment, overall structure, logical step...This paper introduces a nuclear calamity evaluation expert system which is applied to comprehensive evaluation of damage effects of nuclear calamities. It contains hardware environment, overall structure, logical steps and reasoning models, concerning the expert system.展开更多
OBJECTIVE Nuclear factor erythroid 2-related factor 2(Nrf2) is found to be ubiquitiously expressed in many tissues,and works as the key regulator against oxidative stress damage in cells and organs,which makes Nrf2 a ...OBJECTIVE Nuclear factor erythroid 2-related factor 2(Nrf2) is found to be ubiquitiously expressed in many tissues,and works as the key regulator against oxidative stress damage in cells and organs,which makes Nrf2 a widely concerned drug target.Recent research has identified that Nrf2 is involved in the pathology of Alzheimer disease(AD),whereas the mechanism is unknown.The purpose of this study is to figure out the role of Nrf2 in the pathologic process of AD through Nrf2-Keap1-ARE pathway and the effects of Keap1-Nrf2 inhibitor in AD mice models.METHODS Amyloid β^(1-42)(Aβ^(1-42))was injected into the bilateral hippocampus to induce the cognitive dysfunction in eight-week old male mice.The mice were treated with Keap1-Nrf2 inhibitor NXPZ of three doses as well as donepezil as a positive control by intragastric administration one time a day for one week.Several behavior tests were used to analyze the mice learning and memory ability.Additionally,we detected Nrf2 and Aβ in the plasma in mice with ELISA kits,as well as some factors related to oxidative stress in the hippocampus and cortex.The expression levels of Nrf2,Keap1,Tau and p-Tau were measured in the murine brain tissue with Western blotting.SH-SY5 Y cells were studied as an in vitro model to further clarify the mechanism.RESULTS The treatment of NXPZ ameliorated learning and memory dysfunction in AD mice in a dose-dependent manner,and the high dose group recovered better than the positive drug group.The plasma Nrf2 level was increased in a dose-dependent manner in the treatment groups;however,the plasma Aβ was decreased.What′ s more,superoxide dismutase(SOD) and glutathione reductase(GSSH) in the hippocampus and cortex were increased in the treatment group,while the malondialdehyde(MDA) was decreased,meaning that NXPZ treatment promoted expression of the anti-oxidative factors and inhibited the expression of the oxidative factors in the down-stream.Western blotting analysis of hippocampus and cortex showed up-regulated Nrf2,decreased Keap1 and decreased p-Tau in NXPZ treatment mice.In ex vivo experiments,when SH-SY5 Y cells were treated with Aβ,Nrf2 in the cytoplasm was increased,as well as the expression Nrf2 in the nuclear was decreased.The treatment of NXPZ increased nuclear Nrf2,decreased cytoplasm Nrf2,and decreased the expression of p-Tau.CONCLUSION Nrf2 has an important role in neuron function.Nrf2 activation by selective Keap1-Nrf2 inhibitor NXPZ may contribute to improve cognitive function in AD mice.The mechanism may be related to increased generation and release of Nrf2 induced by more disaggregation with Keap1,leading to more expression of anti-oxidative molecules to protect the damage caused by Aβ.These results indicates that Nrf2 may be a novel therapeutic target of AD and Keap1-Nrf2 inhibitor may be a novel medication for protecting the loss of learning and memory ability.展开更多
Prolactin （PRL） is a versatile signaling molecule and regulates a variety of physiological processes, including mammary gland growth and differentiation and the synthesis of milk proteins. While PRL is known to be n...Prolactin （PRL） is a versatile signaling molecule and regulates a variety of physiological processes, including mammary gland growth and differentiation and the synthesis of milk proteins. While PRL is known to be necessary for high levels of milk protein expression, the mechanism by which the synthesis of milk proteins is stimulated at the transcript level is less known. A major modification in the transcript level is protein phosphorylation. To gain additional insights into the molecular mechanisms at the transcript level underlying PRL action on the dairy cow mammary epithelial cells （DCMECs）, nuclear phosphoproteins whose expression distinguishes proliferating regulated by PRL in DCMECs were identified. A phosphoprotein-enriched fraction from nuclear proteins was obtained by affinity chromatography, and a two-dimensional gel electrophoresis （2-DE） and matrix assisted laser desorption/ionization time of matrix-assisted laser desorption/ionization/time of flight mass spectrometry （MALDI-TOF MS） were used to identify the changes of nuclear phosphoproteins in DCMECs treated with prolactin. Seven proteins displaying~〉2-fold difference in abundance upon PRL treatment in DCMECs were identified by MALDI-TOF MS. The protein-GARS （GlyRS）, which belonged to the class-II aminoacyl-tRNA synthetase family, played a global role in the milk protein synthesis. SERPINH1 （Heat shock protein 47）, which was the first heat shock protein found to be a member of the serpin superfamily, regulated physiologic functions, such as complement activation, programmed cell death, and inflammatory processes. PRDX3, which belonged to a family of antioxidant enzymes, played an important role in scavenging intracellular reactive oxygen species （ROS）. ACTR1A, belonged to the actin family, which was associated with transport of p53 to the nucleus. Annexin A2, a Ca2＋-dependent phospholipid-binding protein, maintained the viability and cell cycle regulation of DCMECs. PSMB2 and PSMD10, which belonged to ubiquitin-proteasome system, were involved in several cellular processes, including cell cycle control, cellular stress response, intracellular signaling. This screening revealed that prolactin influenced the level of nuclear phosphoproteins in DCMECs. This result opens new avenues for the study of the molecular mechanism linked to the synthesis of milk proteins.展开更多
A series of experiments were conducted to study the major procedures in nuclear transplantation such as oocyte enucleation and activation, electrofusion and developnent of the nuclear transplant embryos in the mouse, ...A series of experiments were conducted to study the major procedures in nuclear transplantation such as oocyte enucleation and activation, electrofusion and developnent of the nuclear transplant embryos in the mouse, rabbits and sheep. The important results are as follows:11. In the mouse, only 35% of the oocytes collected 15～16 h after hCG had a notable first polar body (FPb) and those without FPb were enucleated by removing cytoplasm from the PVS-wider side and the enucleation rate was similar to that in the oocytes with FPb, and the enucleation rate of removing 1/3 cytoplasm was remarkably higher than that of removing 1/4 cytoplasm. 2. Among the three fusion media tested, mannitol and sucrose solutions produced better results than M2 in electrofusion of mouse 2-cell embryos. Under favorable pulse conditions, the osmotic pressure of fusion medium had no motable effect on electrofusion, but as the conditions became so unfavorable that some embryos began to lyse, the fusion rates in hypertonie mannitol solution were significantly higher than those in isotonic or hypotonic solutions. A wide range of pulse strengths (0.31～2.04 by/ cm) and durations(10～1280 μs) were used and 100% of fusion were obtained in many cases. Optimal pulse durations were plotted for field strengths to obtain high fusion rates (96%～ 100%) in mouse2-cell embryos. 3. With one pulse of 0.45 by / cm, satisfactory results of mouse oocyte activation were obtained only when the duration increased to 160 μs or longer. The activation rate increased as the oocytes got older. Some of the oocytes ar. rested at metaphase Ⅲ after electrical stimulation and their proportion to the number of oocytes not activated increased with egg age. 4. 10% and 31% of the nuclear transplant embryos developed to morula or blastocyst stage in sheep and rabbits, respectively, with Chinese-made hormones and chemicals.展开更多
On the basis of fracture mechanics earthquake rupture model, the relations between source parameters and (0, the value of tectonic ambient shear stress in the place where the earthquake occurs, have been derived. Thus...On the basis of fracture mechanics earthquake rupture model, the relations between source parameters and (0, the value of tectonic ambient shear stress in the place where the earthquake occurs, have been derived. Thus, we can calculate a large number of values of tectonic ambient shear stress or values of background stress in the place where the earthquake occurs. If nuclear explosions are treated as earthquakes in the calculation, we find that (0 values of nuclear explosions have about 20 MPa, which is obviously higher than average (0 values of earthquakes with the same magnitude. This result can be used to discriminate nuclear explosions from earthquakes.展开更多
The dissolution of polyhedra of Mythimna separata nuclear polyhedrosis. virus by digestive fluid (pH11. 03) collected from the 5th instar M. separata larvae was studied in vitro. Observations were made at timed interv...The dissolution of polyhedra of Mythimna separata nuclear polyhedrosis. virus by digestive fluid (pH11. 03) collected from the 5th instar M. separata larvae was studied in vitro. Observations were made at timed intervals using phase contrast microscopy and scanning electron microscopy. Under phase contrast microscopy, the polyhcdra lost their refrigence by 5 minute exposure to the digestive fluid. After exposure to the fluid for 30 minutes, all of the PIBs were dissolved. Chages of the PIBs were also observed under scanning electron microscopy, after 5 minute exposure to the fluid, damaged PIBs and PIB-derived debris were seen. After 30 minute exposure, only remains of PIBs were found. The effect of M. separata digestive fluid on the infectivity of Ms NPV was examined by nconatcs bioassay. The results indicated that virions from Ms NPV-PIBs were rapidly inactivated after 15 minute exposure to digestive fluid and all of virions were non-infectious.展开更多
Cells in vivo reside within a complex microenvironment that is rich in biological,chemical and mechanical cues,playing critical roles in regulating cellular activities(e.g.,proliferation,migration,differentiation)both...Cells in vivo reside within a complex microenvironment that is rich in biological,chemical and mechanical cues,playing critical roles in regulating cellular activities(e.g.,proliferation,migration,differentiation)both spatially and temporally.Although it is well accepted that biochemical cues can significantly influence cell functions,accumulating evidence has also shown that mechanical feedback from the cell microenvironment(e.g.,stiffness of ECM,morphology,and tension force)also plays an important role in controlling cell fate.Disequilibrium of the mechanical microenvironment is associated with a series of diseases,such as cancer migration and tissue fibrosis.Thus,there is a pressing need to understand how cells transduce these mechanobiological cues.The cell cytoskeleton is linked to both the nuclear lamina via LINC complexes and to focal adhesions.This enables the intriguing possibility that forces directly transduced by the nucleus might in fact affect gene expression.Can force transmitted to nucleus and associated alterations to the special organization of genome inside the nucleus modulate gene expression programmes and change cell behaviors? This kind of putative mechanotransduction dominated by the nucleus is termed as nuclear mechanotransduction.Evidence shows that isolated nuclei regulate their stiffness to in response to force applied on nesprin with integrated nuclear lamina and emerin required.Another example is that the force applied on integrins in focal adhesions can be transmitted through actin filaments to the LINC complex and then stretch the chromatin directly through lamina-chromatin interactions.However,the mechanism of nuclear mechanotransduction is still unclear.Three hypotheses have been proposed.The first proposed mechanism is that the proteins on the nuclear lamina are phosphorylated induced by force and their special organization is changed to regulate downstream signal transduction.Transcription factors like YAP and calcium ions would enter the nucleus in the context of force stretching the nuclear lamina and opening nuclear pore complexes(NPC)and calcium channels.Another proposed hypothesis in this case is that force propagated through the cytoskeleton stretches,opens or condenses chromatin directly,leading to an entirely different genome organization.Nevertheless,due to the lack of research methods and instruments,researchers have not reached a consensus on how cells sense external forces and react specifically through nucleus.In this study,we used micropatterned techniques to modify poly(N-isopropyl-acrylamide)(PA)hydrogel surface with fibronectin(FN)which promote cell adhesion to shape-engineer the cells to investigate the effects of matrix stiffness on nuclear mechanotransduction.To illustrate the impact on nuclear shape induced by matrix stiffness,the nuclei were stained byDAPI and observed by a laser confocal microscopy with small step sizes.The nuclear shape index(NSI),which indicate the variation of projected nuclear shape was firstly researched thoroughly.Meanwhile,the nuclear height,width and volume were characterized in this study.To investigate the force transmitted to the nuclei in cells cultured on hydrogels with multiple stiffness,the cell traction force was measured and the cytoskeleton like actin cap was studied by pharmacological treatments.We also found that the impacts of matrix stiffness on nuclear mechanics,which indicated by the condensation of chromatin and the overexpression of Lamin A/C.展开更多
The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE ...The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.展开更多
It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplas...It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplasmic proteins.However,increasing evidence suggests that nuclear mechanotransduction impacts nuclear activities and functions.Recently we have revealed that transgene dihydrofolate reductase(DHFR)gene expression is directly upregulated via cell surface forceinduced stretching of chromatin [2].Here we show that endogenous genes are also upregulated directly by force via integrins.We present evidence on an underlying mechanism of how gene transcription is regulated by force.We have developed a technique of elastic round microgels to quantify 3D tractions in vitro and in vivo[3].We report a synthetic small molecule(which has been stiffened structurally)that inhibits malignant tumor repopulating cell growth in a low-stiffness(force)microenvironment and cancer metastasis in mouse models without detectable toxicity[4].These findings suggest that direct nuclear mechanotransduction impacts mechanobiology and mechanomedicine at cellular and molecular levels.展开更多
[Background]The previous studies suggest that radioactive elements like Cs and Sr may adversely affect marine ecosystems and the fishing industry.Traditional treatment systems for radioactive wastewater like the Advan...[Background]The previous studies suggest that radioactive elements like Cs and Sr may adversely affect marine ecosystems and the fishing industry.Traditional treatment systems for radioactive wastewater like the Advanced Liquid Processing System(ALPS)and Kurion have faced challenges in limiting concentration and achieving safety criteria.Studies suggest potential long-term impacts on benthic organisms and seafood networks due to radioactive elements like Cs and Sr from the discharged radioactive wastewater,which may hinder post-disaster recovery and provoke economic losses in the fishing industry both domestically and internationally.A series of studies indicate that there are issues of Cs and Sr pollution migration in soil and water conservation in Fukushima.[Methods]To provide feasible solutions,the main article includes five nuclear wastewater treatment technologies,and soil and water conservation measures for different media(water and soil)were evaluated through reviewing the previous fifteen years'articles.To provide feasible solutions,the main articles,the phytoextraction technologies in Cs and Sr treatment within different land use areas were wildly analyzed(Camellia japonica,Arabidopsis halleri and other local species).[Results]1)A 99.9%removal rate for Cs^(+)and 99.5%for Sr^(2+)was achieved by the KFe[Fe(CN)_(6)]and BaSO_(4)co-precipitation method.2)For membrane filtration,Sr^(2+)and Cs^(+)were removed using metal-organic framework(MOF/graphene oxide)and ion exchange techniques using inorganic materials like titanosilicates.The absorption efficiency of membrane filtration for Sr^(2+)and Cs^(+)was at least 92%and 94%,respectively.The study analyzed soil and water conservation technologies in different land uses,river basins and catchments.3)The underground water treatment mainly were completed via the membrance technologies like reverse osmosis and Permeable Reactive Barriers(PRB)technologies.The ^(90) Sr concentration decreased 77%-91%compared to the initial concentration by PRB technology.These diverse methods offered effective strategies for radioactive wastewater treatment,especially the co-precipitation method may be feasible remediation measures to ensure ecological safety surrounding nuclear power utilizing areas.Soil and water conservation measures for soil pollution treatment mainly focused on the use of stabilizers to hinder the migration of Cs and Sr in the soil and the effects of wind erosion such as interpolyelectrolyte complexes.[Conclusions]We evaluated the pollution of Cs and Sr in the Fukushima nuclear radiation soil and water to provide solutions for the treatment of nuclear wastewater and to prevent radionuclide pollutants from migrating into the soil and water.展开更多
基金Supported by the Key Laboratory Fund for Equipment Pre-Research(6142207210202)。
文摘Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background,an infrared small target detection method based on the tensor nuclear norm and direction residual weighting was proposed.Based on converting the infrared image into an infrared patch tensor model,from the perspective of the low-rank nature of the background tensor,and taking advantage of the difference in contrast between the background and the target in different directions,we designed a double-neighborhood local contrast based on direction residual weighting method(DNLCDRW)combined with the partial sum of tensor nuclear norm(PSTNN)to achieve effective background suppression and recovery of infrared small targets.Experiments show that the algorithm is effective in suppressing the background and improving the detection ability of the target.
基金Project(2009CB623105) supported by the National Basic Research Program of ChinaProject(51108341) supported by the National Natural Science Foundation of ChinaProjects(20110490703, 2012T50437) supported by China Postdoctoral Science Foundation
文摘The low field nuclear magnetic resonance (NMR), as a nondestructive and noninvasive technique, was employed to investigate the water distribution and content in cement paste with different water-to-cement ratio (w/c ratio) during early and later hydration stages. From the water distribution spectrum deduced from relaxation time distribution in paste, it is suggested that the water fills in the capillary pores at initial period, and then diffuses to the mesopores and gel pores in hydration products with the hydration proceeding. The decrease of peak area in water distribution spectrum reflects the transformation from physically bound water to chemically bound water. In addition, based on the connection between relaxation time and pore size, the relative content changes of water in various states and constrained in different types of pores were also measured. The results demonstrate that it is influenced by the formation of pore system and the original water-to-cement ratio in the paste. Consequently, the relative content of capillary water is dropped to less than 2% in the paste with low w/c ratio of 0.3 when being hydrated for 1 d, while the contents are still 16% and 36% in the pastes with w/c ratios of 0.4 and 0.5, respectively.
基金Project(KFJJ-TZ-2019-3)supported by the Open Project of Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil&Gas Reservoirs,ChinaProjects(51504275,51974344)supported by the National Natural Science Foundation of China。
文摘Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.However,with respect to its capacity in expanding macroscopic sweep volume under varying heterogeneities,the related results appear inadequate.In this research,three cores with different heterogeneities were used and flooded by the joint water and CO_(2) WAG,then the effects of heterogeneity on oil recovery were determined.More importantly,the cores after CO_(2) WAG injection were investigated using the nuclear magnetic resonance(NMR)technique for remaining oil distribution research,which could help us to understand the capacity of CO_(2) WAG in enlarging sweep volume at different heterogeneities.The results show that the presence of heterogeneity may largely weaken the effectiveness of water flooding,the more severe the heterogeneity,the worse the water flooding.The WAG injection of CO_(2) performs well in EOR after water flooding for all the cores with different heterogeneities;however,it could barely form a complete or full sweep throughout the low-permeability region,and un-swept bypassed regions remain.The homogeneous core is better developed by the injection of the joint water and CO_(2) WAG than the heterogeneous and fractured cases.
基金Project(10405024) supported by the National Natural Science Foundation of ChinaProject supported by International Thermonuclear Experimental Reactor Organization in France
文摘Modal analysis and seismic response analysis were carried out for the equatorial diagnostic port plug of international thermonuclear experimental reactor (ITER). The aim of the theoretical analysis is to verify structural strength and reliability of the device. The working condition includes one-dimensional seismic wave and two-dimensional seismic wave. Modal analysis of the device shows that primary vibration is inclined to occur in low-order modes. The horizontal (X-direction, Y-direction) maximum vibration appears at the first and the fourth eigen modes, with the natural frequency of 70.59 and 215.88 Hz respectively, and the vertical (Z-direction) primary vibration appears at the second eigen mode with the natural frequency of 82.85 Hz. According to the results of the finite element analysis (FEA) program, the weak portions of the device are distributed in the joint of port body with blanket shielding module (BSM) and inner side wall of ribbed plate for lifting flange, the maximum von Mises stress is 14.8 MPa with the Y-direction seismic wave. In accordance with the design criteria, the destructive effect is far below the failure boundary, and the structural reliability of the equatorial diagnostic port plug can meet the requirements of the design specifications.
基金Project(265201248) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(41172130) supported by the National Natural Science Foundation of China+2 种基金Project(2011ZX05014-001) supported by the Major State S&T Special Fund,ChinaProject(201205002) supported by the China Scholarship CouncilProject(2011D-5006-0305) supported by the China National Petroleum Co.Innovation Foundation,China
文摘The microscopic response characteristics of nuclear magnetic resonance(NMR) are widely used for characterizing complex pore structures of rocks. Due to the prohibitive NMR experiment cost, numerical simulation was employed as an alternative approach to verify some theoretical aspects of NMR responses. Firstly, the basic principles of pore-scale NMR simulation based on random-walk method(RWM) were introduced. The RWM-simulated results were benchmarked with the analytical results for an ideal spherical pore model. Then, the effects of two numerical parameters, namely diffusion radius and walk numbers, were studied on the simulation accuracy. The simulation method is then applied to various pore models with different pore sizes and pore shapes filled with different fluids to study the microscopic NMR response characteristics. The numerical experiments are useful for understanding and interpreting NMR measurements and the simulation code provides a numerical tool to perform pixel-based digital rock analysis.
基金supported by the National Natural Science Foundation of China(6140130861572063)+7 种基金the Natural Science Foundation of Hebei Province(F2016201142F2016201187)the Natural Social Foundation of Hebei Province(HB15TQ015)the Science Research Project of Hebei Province(QN2016085ZC2016040)the Science and Technology Support Project of Hebei Province(15210409)the Natural Science Foundation of Hebei University(2014-303)the National Comprehensive Ability Promotion Project of Western and Central China
文摘As synthetic aperture radar（SAR） has been widely used nearly in every field, SAR image de-noising became a very important research field. A new SAR image de-noising method based on texture strength and weighted nuclear norm minimization（WNNM） is proposed. To implement blind de-noising, the accurate estimation of noise variance is very important. So far, it is still a challenge to estimate SAR image noise level accurately because of the rich texture. Principal component analysis（PCA） and the low rank patches selected by image texture strength are used to estimate the noise level. With the help of noise level, WNNM can be expected to SAR image de-noising. Experimental results show that the proposed method outperforms many excellent de-noising algorithms such as Bayes least squares-Gaussian scale mixtures（BLS-GSM） method, non-local means（NLM） filtering in terms of both quantitative measure and visual perception quality.
文摘This paper introduces a nuclear calamity evaluation expert system which is applied to comprehensive evaluation of damage effects of nuclear calamities. It contains hardware environment, overall structure, logical steps and reasoning models, concerning the expert system.
基金National Natural Science Foundation of China(81703520).
文摘OBJECTIVE Nuclear factor erythroid 2-related factor 2(Nrf2) is found to be ubiquitiously expressed in many tissues,and works as the key regulator against oxidative stress damage in cells and organs,which makes Nrf2 a widely concerned drug target.Recent research has identified that Nrf2 is involved in the pathology of Alzheimer disease(AD),whereas the mechanism is unknown.The purpose of this study is to figure out the role of Nrf2 in the pathologic process of AD through Nrf2-Keap1-ARE pathway and the effects of Keap1-Nrf2 inhibitor in AD mice models.METHODS Amyloid β^(1-42)(Aβ^(1-42))was injected into the bilateral hippocampus to induce the cognitive dysfunction in eight-week old male mice.The mice were treated with Keap1-Nrf2 inhibitor NXPZ of three doses as well as donepezil as a positive control by intragastric administration one time a day for one week.Several behavior tests were used to analyze the mice learning and memory ability.Additionally,we detected Nrf2 and Aβ in the plasma in mice with ELISA kits,as well as some factors related to oxidative stress in the hippocampus and cortex.The expression levels of Nrf2,Keap1,Tau and p-Tau were measured in the murine brain tissue with Western blotting.SH-SY5 Y cells were studied as an in vitro model to further clarify the mechanism.RESULTS The treatment of NXPZ ameliorated learning and memory dysfunction in AD mice in a dose-dependent manner,and the high dose group recovered better than the positive drug group.The plasma Nrf2 level was increased in a dose-dependent manner in the treatment groups;however,the plasma Aβ was decreased.What′ s more,superoxide dismutase(SOD) and glutathione reductase(GSSH) in the hippocampus and cortex were increased in the treatment group,while the malondialdehyde(MDA) was decreased,meaning that NXPZ treatment promoted expression of the anti-oxidative factors and inhibited the expression of the oxidative factors in the down-stream.Western blotting analysis of hippocampus and cortex showed up-regulated Nrf2,decreased Keap1 and decreased p-Tau in NXPZ treatment mice.In ex vivo experiments,when SH-SY5 Y cells were treated with Aβ,Nrf2 in the cytoplasm was increased,as well as the expression Nrf2 in the nuclear was decreased.The treatment of NXPZ increased nuclear Nrf2,decreased cytoplasm Nrf2,and decreased the expression of p-Tau.CONCLUSION Nrf2 has an important role in neuron function.Nrf2 activation by selective Keap1-Nrf2 inhibitor NXPZ may contribute to improve cognitive function in AD mice.The mechanism may be related to increased generation and release of Nrf2 induced by more disaggregation with Keap1,leading to more expression of anti-oxidative molecules to protect the damage caused by Aβ.These results indicates that Nrf2 may be a novel therapeutic target of AD and Keap1-Nrf2 inhibitor may be a novel medication for protecting the loss of learning and memory ability.
基金Supported by Major State Basic Research Development Program of China(973 Program,2011CB100804)
文摘Prolactin （PRL） is a versatile signaling molecule and regulates a variety of physiological processes, including mammary gland growth and differentiation and the synthesis of milk proteins. While PRL is known to be necessary for high levels of milk protein expression, the mechanism by which the synthesis of milk proteins is stimulated at the transcript level is less known. A major modification in the transcript level is protein phosphorylation. To gain additional insights into the molecular mechanisms at the transcript level underlying PRL action on the dairy cow mammary epithelial cells （DCMECs）, nuclear phosphoproteins whose expression distinguishes proliferating regulated by PRL in DCMECs were identified. A phosphoprotein-enriched fraction from nuclear proteins was obtained by affinity chromatography, and a two-dimensional gel electrophoresis （2-DE） and matrix assisted laser desorption/ionization time of matrix-assisted laser desorption/ionization/time of flight mass spectrometry （MALDI-TOF MS） were used to identify the changes of nuclear phosphoproteins in DCMECs treated with prolactin. Seven proteins displaying~〉2-fold difference in abundance upon PRL treatment in DCMECs were identified by MALDI-TOF MS. The protein-GARS （GlyRS）, which belonged to the class-II aminoacyl-tRNA synthetase family, played a global role in the milk protein synthesis. SERPINH1 （Heat shock protein 47）, which was the first heat shock protein found to be a member of the serpin superfamily, regulated physiologic functions, such as complement activation, programmed cell death, and inflammatory processes. PRDX3, which belonged to a family of antioxidant enzymes, played an important role in scavenging intracellular reactive oxygen species （ROS）. ACTR1A, belonged to the actin family, which was associated with transport of p53 to the nucleus. Annexin A2, a Ca2＋-dependent phospholipid-binding protein, maintained the viability and cell cycle regulation of DCMECs. PSMB2 and PSMD10, which belonged to ubiquitin-proteasome system, were involved in several cellular processes, including cell cycle control, cellular stress response, intracellular signaling. This screening revealed that prolactin influenced the level of nuclear phosphoproteins in DCMECs. This result opens new avenues for the study of the molecular mechanism linked to the synthesis of milk proteins.
文摘A series of experiments were conducted to study the major procedures in nuclear transplantation such as oocyte enucleation and activation, electrofusion and developnent of the nuclear transplant embryos in the mouse, rabbits and sheep. The important results are as follows:11. In the mouse, only 35% of the oocytes collected 15～16 h after hCG had a notable first polar body (FPb) and those without FPb were enucleated by removing cytoplasm from the PVS-wider side and the enucleation rate was similar to that in the oocytes with FPb, and the enucleation rate of removing 1/3 cytoplasm was remarkably higher than that of removing 1/4 cytoplasm. 2. Among the three fusion media tested, mannitol and sucrose solutions produced better results than M2 in electrofusion of mouse 2-cell embryos. Under favorable pulse conditions, the osmotic pressure of fusion medium had no motable effect on electrofusion, but as the conditions became so unfavorable that some embryos began to lyse, the fusion rates in hypertonie mannitol solution were significantly higher than those in isotonic or hypotonic solutions. A wide range of pulse strengths (0.31～2.04 by/ cm) and durations(10～1280 μs) were used and 100% of fusion were obtained in many cases. Optimal pulse durations were plotted for field strengths to obtain high fusion rates (96%～ 100%) in mouse2-cell embryos. 3. With one pulse of 0.45 by / cm, satisfactory results of mouse oocyte activation were obtained only when the duration increased to 160 μs or longer. The activation rate increased as the oocytes got older. Some of the oocytes ar. rested at metaphase Ⅲ after electrical stimulation and their proportion to the number of oocytes not activated increased with egg age. 4. 10% and 31% of the nuclear transplant embryos developed to morula or blastocyst stage in sheep and rabbits, respectively, with Chinese-made hormones and chemicals.
文摘On the basis of fracture mechanics earthquake rupture model, the relations between source parameters and (0, the value of tectonic ambient shear stress in the place where the earthquake occurs, have been derived. Thus, we can calculate a large number of values of tectonic ambient shear stress or values of background stress in the place where the earthquake occurs. If nuclear explosions are treated as earthquakes in the calculation, we find that (0 values of nuclear explosions have about 20 MPa, which is obviously higher than average (0 values of earthquakes with the same magnitude. This result can be used to discriminate nuclear explosions from earthquakes.
基金The project is supperted by National Natural Science Fundation of China
文摘The dissolution of polyhedra of Mythimna separata nuclear polyhedrosis. virus by digestive fluid (pH11. 03) collected from the 5th instar M. separata larvae was studied in vitro. Observations were made at timed intervals using phase contrast microscopy and scanning electron microscopy. Under phase contrast microscopy, the polyhcdra lost their refrigence by 5 minute exposure to the digestive fluid. After exposure to the fluid for 30 minutes, all of the PIBs were dissolved. Chages of the PIBs were also observed under scanning electron microscopy, after 5 minute exposure to the fluid, damaged PIBs and PIB-derived debris were seen. After 30 minute exposure, only remains of PIBs were found. The effect of M. separata digestive fluid on the infectivity of Ms NPV was examined by nconatcs bioassay. The results indicated that virions from Ms NPV-PIBs were rapidly inactivated after 15 minute exposure to digestive fluid and all of virions were non-infectious.
基金supported by the National Natural Science Foundation of China ( 11522219,11532009)
文摘Cells in vivo reside within a complex microenvironment that is rich in biological,chemical and mechanical cues,playing critical roles in regulating cellular activities(e.g.,proliferation,migration,differentiation)both spatially and temporally.Although it is well accepted that biochemical cues can significantly influence cell functions,accumulating evidence has also shown that mechanical feedback from the cell microenvironment(e.g.,stiffness of ECM,morphology,and tension force)also plays an important role in controlling cell fate.Disequilibrium of the mechanical microenvironment is associated with a series of diseases,such as cancer migration and tissue fibrosis.Thus,there is a pressing need to understand how cells transduce these mechanobiological cues.The cell cytoskeleton is linked to both the nuclear lamina via LINC complexes and to focal adhesions.This enables the intriguing possibility that forces directly transduced by the nucleus might in fact affect gene expression.Can force transmitted to nucleus and associated alterations to the special organization of genome inside the nucleus modulate gene expression programmes and change cell behaviors? This kind of putative mechanotransduction dominated by the nucleus is termed as nuclear mechanotransduction.Evidence shows that isolated nuclei regulate their stiffness to in response to force applied on nesprin with integrated nuclear lamina and emerin required.Another example is that the force applied on integrins in focal adhesions can be transmitted through actin filaments to the LINC complex and then stretch the chromatin directly through lamina-chromatin interactions.However,the mechanism of nuclear mechanotransduction is still unclear.Three hypotheses have been proposed.The first proposed mechanism is that the proteins on the nuclear lamina are phosphorylated induced by force and their special organization is changed to regulate downstream signal transduction.Transcription factors like YAP and calcium ions would enter the nucleus in the context of force stretching the nuclear lamina and opening nuclear pore complexes(NPC)and calcium channels.Another proposed hypothesis in this case is that force propagated through the cytoskeleton stretches,opens or condenses chromatin directly,leading to an entirely different genome organization.Nevertheless,due to the lack of research methods and instruments,researchers have not reached a consensus on how cells sense external forces and react specifically through nucleus.In this study,we used micropatterned techniques to modify poly(N-isopropyl-acrylamide)(PA)hydrogel surface with fibronectin(FN)which promote cell adhesion to shape-engineer the cells to investigate the effects of matrix stiffness on nuclear mechanotransduction.To illustrate the impact on nuclear shape induced by matrix stiffness,the nuclei were stained byDAPI and observed by a laser confocal microscopy with small step sizes.The nuclear shape index(NSI),which indicate the variation of projected nuclear shape was firstly researched thoroughly.Meanwhile,the nuclear height,width and volume were characterized in this study.To investigate the force transmitted to the nuclei in cells cultured on hydrogels with multiple stiffness,the cell traction force was measured and the cytoskeleton like actin cap was studied by pharmacological treatments.We also found that the impacts of matrix stiffness on nuclear mechanics,which indicated by the condensation of chromatin and the overexpression of Lamin A/C.
基金Supported by Basic and Applied Basic Research Project of Guangdong Province(2021B0301030006)。
文摘The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.
基金supported by funds from National Institutes of Health,USA and Huazhong University of Science and Technology,Wuhan,Chinathe support from Hoeft Professorship at University of Illinois at Urbana-Champaign
文摘It is known that mechanical forces play critical roles in physiology and diseases but the underlying mechanisms remain largely unknown[1].Most studies on the role of forces focus on cell surface molecules and cytoplasmic proteins.However,increasing evidence suggests that nuclear mechanotransduction impacts nuclear activities and functions.Recently we have revealed that transgene dihydrofolate reductase(DHFR)gene expression is directly upregulated via cell surface forceinduced stretching of chromatin [2].Here we show that endogenous genes are also upregulated directly by force via integrins.We present evidence on an underlying mechanism of how gene transcription is regulated by force.We have developed a technique of elastic round microgels to quantify 3D tractions in vitro and in vivo[3].We report a synthetic small molecule(which has been stiffened structurally)that inhibits malignant tumor repopulating cell growth in a low-stiffness(force)microenvironment and cancer metastasis in mouse models without detectable toxicity[4].These findings suggest that direct nuclear mechanotransduction impacts mechanobiology and mechanomedicine at cellular and molecular levels.
基金Xiong′an New Area Science and Technology Innovation Project(2022XACX1000)。
文摘[Background]The previous studies suggest that radioactive elements like Cs and Sr may adversely affect marine ecosystems and the fishing industry.Traditional treatment systems for radioactive wastewater like the Advanced Liquid Processing System(ALPS)and Kurion have faced challenges in limiting concentration and achieving safety criteria.Studies suggest potential long-term impacts on benthic organisms and seafood networks due to radioactive elements like Cs and Sr from the discharged radioactive wastewater,which may hinder post-disaster recovery and provoke economic losses in the fishing industry both domestically and internationally.A series of studies indicate that there are issues of Cs and Sr pollution migration in soil and water conservation in Fukushima.[Methods]To provide feasible solutions,the main article includes five nuclear wastewater treatment technologies,and soil and water conservation measures for different media(water and soil)were evaluated through reviewing the previous fifteen years'articles.To provide feasible solutions,the main articles,the phytoextraction technologies in Cs and Sr treatment within different land use areas were wildly analyzed(Camellia japonica,Arabidopsis halleri and other local species).[Results]1)A 99.9%removal rate for Cs^(+)and 99.5%for Sr^(2+)was achieved by the KFe[Fe(CN)_(6)]and BaSO_(4)co-precipitation method.2)For membrane filtration,Sr^(2+)and Cs^(+)were removed using metal-organic framework(MOF/graphene oxide)and ion exchange techniques using inorganic materials like titanosilicates.The absorption efficiency of membrane filtration for Sr^(2+)and Cs^(+)was at least 92%and 94%,respectively.The study analyzed soil and water conservation technologies in different land uses,river basins and catchments.3)The underground water treatment mainly were completed via the membrance technologies like reverse osmosis and Permeable Reactive Barriers(PRB)technologies.The ^(90) Sr concentration decreased 77%-91%compared to the initial concentration by PRB technology.These diverse methods offered effective strategies for radioactive wastewater treatment,especially the co-precipitation method may be feasible remediation measures to ensure ecological safety surrounding nuclear power utilizing areas.Soil and water conservation measures for soil pollution treatment mainly focused on the use of stabilizers to hinder the migration of Cs and Sr in the soil and the effects of wind erosion such as interpolyelectrolyte complexes.[Conclusions]We evaluated the pollution of Cs and Sr in the Fukushima nuclear radiation soil and water to provide solutions for the treatment of nuclear wastewater and to prevent radionuclide pollutants from migrating into the soil and water.
