Effects of five incubation temperatures (25℃ ,28℃ ,31℃ ,35℃ and 37℃ for 24hours) and four incubation time periods (0.4,16 and 24 hours at 35℃) on isolated microspore culture of Chinese cabbage were studied. The ...Effects of five incubation temperatures (25℃ ,28℃ ,31℃ ,35℃ and 37℃ for 24hours) and four incubation time periods (0.4,16 and 24 hours at 35℃) on isolated microspore culture of Chinese cabbage were studied. The results showed that cultured microspores of Chinese cabbage developed into embryos at all the incubation temperatues from 28℃ to 37℃ ,but the best response to high temperature occured at 35℃. Among the four kinds of time periods, the highest yield of embryos was obtained at the 24h treatment. Therefore, the isolated microspore culture of Chinese cabbege ran be efficiently carried out at 35℃ for 24 hours.展开更多
The supported isolated Pt atoms(Pt iso)and other rare metals have attracted intensive concern due to their maximized metal utilization efficiency,unique reactivity or selectivity,connection to organometallic catalysis...The supported isolated Pt atoms(Pt iso)and other rare metals have attracted intensive concern due to their maximized metal utilization efficiency,unique reactivity or selectivity,connection to organometallic catalysis and the potential for making well-defined active sites[1-3].As catalytic active sites,oxide-supported isolated Pt-group metal atoms are well known for their unique reactivity and efficient metal utilization[4-6].Even continuous efforts have been made,it is still challenging to characterize the intrinsic ca-talytic activity of these dispersed active sites on oxide supports at a level that relates local electronic and geometric structure to function,because of their atomic dispersion,heterogeneity in the local coordination,dynamic changes in local coordination under reactive environments and low loading of metal[7-9].展开更多
A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensi...A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.展开更多
OBJECTIVE To evaluate the effects of flavonoids from Xindakang(Hippophae Fructus flavone)on myocardial systolic and diastolic functions of isolated frog hearts and explore the possible mechanism,and provide experiment...OBJECTIVE To evaluate the effects of flavonoids from Xindakang(Hippophae Fructus flavone)on myocardial systolic and diastolic functions of isolated frog hearts and explore the possible mechanism,and provide experimental basis for improving the effect and efficacy of Xindakang on cardiac function.METHODS The isolated frog heart perfusion specimens were prepared by Yagi′s method,and the effects of different concentrations of Xindakang on myocardial contractility(0.0125,0.025,0.05,0.1 and 0.2 g·L^(-1)),heart rate and cardiac output of isolated frog heart were studied.Acetylcholine,atropine and epinephrine were administered successively to analyze the effects of Xindakang on cardiac systolic function of isolated frogs under the action of different drugs,and compared with propranolol.The effect of extracellular calcium ion concentration on the action of Xindakang was studied by using low calcium concentration,high calcium concentration and normal Ren′s solution.To study the effect and possible mechanism of Xindakang on cardiac systolic function of frog.RESULTS The concentration of Xindakang in the range of 0.0125-0.1 g·L^(-1)could weaken the contractility of isolated frog heart and increase the concentration of Xindakang.The inhibitory effect of Xindakang on contractility of isolated frog heart was enhanced,and showed obvious dose-effect relationship.Cardiac output was significantly decreased by Xindakang(P<0.01),slow heart rate(P<0.05);M receptor blocker atropine could not antagonize the contractile effect of Xindakang,and Xindakang could not completely antagonize the contractile effect of adrenalin.Xindakang could inhibit the isolated frog heart in low calcium concentration,high calcium concentration and normal Ren′s solution,and increased with the increase of extracellular calcium concentration(P<0.01).CONCLUSION Xindakang has inhibitory effect on isolated frog heart,which may be achieved by blocking the calcium channel on myocardial cell membrane and reducing the calcium concentration in myocardial cells.展开更多
An isolated slit was placed in a single box girder to obtain passive leading-edge suction and trailing-edge jet flow to control the unsteady aerodynamic force and modify the flow structure.The Great Belt East Bridge w...An isolated slit was placed in a single box girder to obtain passive leading-edge suction and trailing-edge jet flow to control the unsteady aerodynamic force and modify the flow structure.The Great Belt East Bridge was used as a physical model at a geometric scale of 1:125.Wind tunnel experiments were conducted at an incoming airflow speed of 10 m/s,and the Reynolds number was calculated as 2.3×104 using the test model height and wind speed.The surface pressure distribution was measured,and the aerodynamic force acting on the test model with and without the isolated slit was calculated by integrating the pressure result.It was found that the control using an isolated slit can dramatically decrease the fluctuating surface pressure distribution and aerodynamic force.An analysis on the power spectral density of the lift force revealed that the isolated slit accelerated vortex shedding.Moreover,high-speed particle image velocimetry was used to investigate the wake flow structure behind the test model.A vortex separated from the upper surface was pushed to a lower location and the wake flow structure was modified by the isolated slit.A proper orthogonal decomposition(POD)of the flow field showed that the first two POD modes in the controlled case contributed less energy than those in the uncontrolled case,indicating that more energy was transferred to higher modes,and small-scale vortices had more energy.A secondary instability structure was found in the wake flow for a nondimensional jet momentum coefficient J of 0.0667.展开更多
The plant pathogen Verticillium dahliae causes severe cotton losses in Uzbekistan. To create cotton varieties that are resistant to the more virulent races of V.dahliae we wanted to determine
A novel method isolated microorganisms in soil granule was built. The key steps included： repeated elutriation of soil by sterilized water, inoculation on the plates with the elutriated sediments, incubation of the p...A novel method isolated microorganisms in soil granule was built. The key steps included： repeated elutriation of soil by sterilized water, inoculation on the plates with the elutriated sediments, incubation of the plates and isolation of the actinomycetes by using selected culture medium. We formulated that most microflora included the dominant actinomycetes in the soil were carried away with the sterilized water in the elutriation procedure, some rare actinomycetes and few other microflora included bacteria were remained in the elutriated sediments, the other microflora were excluded to grew into colonies on the plates by using selective culture medium for actinomycetes in the elutriated sediments. Results showed the supposition. Non-streptomycete actinomycetes were isolated both from black soil samples from Chinese northeast area and compost samples from Chinese central area. Soil fungi in granule were isolated by using the selective conditions to favor fungi. The results showed that the method was effective展开更多
In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The e...In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The effects of the divergence, straight, and convergence isolators on the rotating detonation wave dynamics and the upstream oblique shock wave propagation mechanism are analyzed. The differences in the rotating detonation wave behaviors between ground and flight operations are clarified.The results indicate that the propagation regimes of the upstream oblique shock wave depend on the isolator configurations and operation conditions. With a divergence isolator, the airflow is accelerated throughout the isolator and divergence section, leading to a maximum Mach number(~1.8) before the normal shock. The total pressure loss reaches the largest, and the detonation pressure drops. The upstream oblique shock wave can be suppressed within the divergence section with the divergence isolator.However, for the straight and convergence isolators, the airflow in the isolator with a larger ψ_(1)(0.3 and0.4) can suffer from the disturbance of the upstream oblique shock wave. The critical incident angle is around 39° at ground operation conditions. The upstream oblique shock wave tends to be suppressed when the engine operates under flight operation conditions. The critical pressure ratio β_(cr0) is found to be able to help in distinguishing the propagation regimes of the upstream oblique shock wave. Slightly below or above the β_(cr0) can obtain different marginal propagation results. The high-speed airflow in the divergence section affects the fuel droplet penetration distance, which deteriorates the reactant mixing and the detonation area. Significant detonation velocity deficits are observed and the maximum velocity deficit reaches 26%. The results indicate the engine channel design should adopt different isolator configurations based on the purpose of total pressure loss or disturbance suppression. This study can provide useful guidance for the channel design of a more complete two-phase rotating detonation engine.展开更多
Background Cotton is an important crop providing the most natural fibers all over the world. The cotton genomics community has utilized whole genome sequencing data to construct an elite gene pool in which functional ...Background Cotton is an important crop providing the most natural fibers all over the world. The cotton genomics community has utilized whole genome sequencing data to construct an elite gene pool in which functional genes are related to agronomic traits. However, the functional validation of these genes is hindered by time-consuming and inefficient genetic transformation methods. Thus, establishing a transient transformation system of high efficiency is necessary for cotton genomics.Results To improve the efficiency of transient transformation, we used the protoplasts isolated from the etiolated cotyledon as recipient. The enzymatic digestion buffer comprised 1.5%(w/v) cellulase, 0.75%(w/v) macerozyme, and 1% hemicellulase, osmotically buffered with 0.4 mol·L^(-1) mannitol. After 5 h of dark incubation at 25℃, uniform cotton protoplasts were successfully isolated with a yield of 4.6 × 10^(6) protoplasts per gram(fresh weight) and 95% viability. We incubated 100 μL protoplasts(2.5 × 10^(5)·m L^(-1)) with 15 μg plasmid in the solution of 0.4 mol·L^(-1) mannitol and 40% PEG 4000 for 15 min, ultimately achieving an optimal transient transfection efficiency of 71.47%.Conclusions This transient system demonstrated effective utility in cellular biology research through successful applications in subcellular localization analyses, bimolecular fluorescence complementation(Bi FC) verification, and prime editing vector validation. Through systematic optimization, we established an efficient and expedited protoplast-based transient transformation system and successfully applied this platform to cotton functional genomics studies.展开更多
The process of ground vehicle dynamic gravimetry is inevitably affected by the carrier’s maneuvering acceleration,which makes the result contain a large amount of dynamic error.In this paper,we propose a dynamic erro...The process of ground vehicle dynamic gravimetry is inevitably affected by the carrier’s maneuvering acceleration,which makes the result contain a large amount of dynamic error.In this paper,we propose a dynamic error suppression method of gravimetry based on the high-precision acquisition of external velocity for compensating the horizontal error of the inertial plat-form.On the basis of platform gravity measurement,firstly,the dynamic performance of the system is enhanced by optimizing the horizontal damping network of the inertial platform and selecting its parameter.Secondly,an improved federal Kalman filtering algorithm and a fault diagnosis method are designed using strapdown inertial navigation system(SINS),odometer(OD),and laser Doppler velocimeter(LDV).Simulation validates that these methods can improve the accuracy and robustness of the external velocity acquisition.Three survey lines are selected in Tianjin,China,for the gravimetry experiments with different maneuvering levels,and the results demonstrate that after dynamic error suppression,the internal coincidence accuracies of smooth and uniform operation,obvious acceleration and deceleration operation,and high-dynamic operation are improved by 70.2%,73.6%,and 77.9%to reach 0.81 mGal,1.30 mGal,and 1.94 mGal,respectively,and the external coinci-dence accuracies during smooth and uniform operation are improved by 48.6%up to 1.66 mGal.It is shown that the pro-posed method can effectively suppress the dynamic error,and that the accuracy improvement increases with carrier maneuver-ability.However,the amount of residual error that can not be entirely eliminated increases as well,so the ground vehicle dynamic gravimetry should be maintained in the carrier for smooth and uniform operation.展开更多
The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructi...The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.展开更多
High-static-low-dynamic stiffness (HSLDS) vibration isolators have been demonstrated to be an effective means of attenuating low-frequency vibrations, and may be utilized for ship shafting applications to mitigate tor...High-static-low-dynamic stiffness (HSLDS) vibration isolators have been demonstrated to be an effective means of attenuating low-frequency vibrations, and may be utilized for ship shafting applications to mitigate torsional vibration. This paper presents the construction of a highly compact HSLDS torsional vibration isolator by connecting positive and negative stiffness components in paral lel. Based on mechanical model analysis, the restoring torque of negative stiffness components is de rived from their springs and connecting rods, while that of positive stiffness components is obtained through their circular section flexible rods. The quasizero stiffness characteristics of the HSLDS iso lator are achieved through a combination of static structural simulation and experimental test. The tor sional vibration isolation performance is assessed by means of numerical simulation and theory analy sis. Finally, the frequency-sweep vibration test is conducted. The test results indicate that the HSLDS torsional vibration isolator exhibits superior low-frequency isolation performance compared to its linear counterpart, rendering it a promising solution for mitigating low-frequency torsional vi bration in ship shafting.展开更多
Our current project is to isolate,identify andcharacterize cotton fiber-specific genes in orderto pick up candidates for fiber qualityimprovement.Firstly,10DPA(day postanthesis)cotton fiber cDNA library wasconstructed...Our current project is to isolate,identify andcharacterize cotton fiber-specific genes in orderto pick up candidates for fiber qualityimprovement.Firstly,10DPA(day postanthesis)cotton fiber cDNA library wasconstructed with 5X106 primary titer and 1.展开更多
Based on the numerical simulation of solidification, a computer aid design(CAD) software package of casting technique was developed to design the rising system intelligently. The software can calculate the size and lo...Based on the numerical simulation of solidification, a computer aid design(CAD) software package of casting technique was developed to design the rising system intelligently. The software can calculate the size and locate the situations of the isolated melts. According to the liquid shrinkage of each isolated melts and the standard parameters of risers in the database, the riser’s situation and the size can be identified intelligently as long as the riser’s shape is selected. 3-D software and simulation analysis of CAST soft/computer aid engineering(CAE) software show that the design of the riser and the running system is feasible.展开更多
The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high lev...The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.展开更多
文摘Effects of five incubation temperatures (25℃ ,28℃ ,31℃ ,35℃ and 37℃ for 24hours) and four incubation time periods (0.4,16 and 24 hours at 35℃) on isolated microspore culture of Chinese cabbage were studied. The results showed that cultured microspores of Chinese cabbage developed into embryos at all the incubation temperatues from 28℃ to 37℃ ,but the best response to high temperature occured at 35℃. Among the four kinds of time periods, the highest yield of embryos was obtained at the 24h treatment. Therefore, the isolated microspore culture of Chinese cabbege ran be efficiently carried out at 35℃ for 24 hours.
文摘The supported isolated Pt atoms(Pt iso)and other rare metals have attracted intensive concern due to their maximized metal utilization efficiency,unique reactivity or selectivity,connection to organometallic catalysis and the potential for making well-defined active sites[1-3].As catalytic active sites,oxide-supported isolated Pt-group metal atoms are well known for their unique reactivity and efficient metal utilization[4-6].Even continuous efforts have been made,it is still challenging to characterize the intrinsic ca-talytic activity of these dispersed active sites on oxide supports at a level that relates local electronic and geometric structure to function,because of their atomic dispersion,heterogeneity in the local coordination,dynamic changes in local coordination under reactive environments and low loading of metal[7-9].
文摘A series of soy protein isolate(SPI)films plasticized by glycerol(Gly)were studied using attenuated total reflectance-Fourier transform infrared spectroscopy(ATR/FTIR).Perturbation-correlation movingwindow two-dimensional(PCMW2D)and two-dimensional correlation(2DCOS)analyses were applied to the amideⅠband and thus the hydrogen bond interaction between SPI and Gly was systematically investigated.When Gly concentrations were in the range 0~35%,the hydrogen bond amongβ-sheets was replaced by the one between SPI chain and Gly molecule,which caused these protein chains being changed toα-helix.However,the transformation ofβ-sheet toα-helix was saturated and both of them tend to change to random coil when Gly concentrations were in the range 35%~60%.
基金Natural Science Foundation of Tibet Autonomous Region(2015ZR-13-16)。
文摘OBJECTIVE To evaluate the effects of flavonoids from Xindakang(Hippophae Fructus flavone)on myocardial systolic and diastolic functions of isolated frog hearts and explore the possible mechanism,and provide experimental basis for improving the effect and efficacy of Xindakang on cardiac function.METHODS The isolated frog heart perfusion specimens were prepared by Yagi′s method,and the effects of different concentrations of Xindakang on myocardial contractility(0.0125,0.025,0.05,0.1 and 0.2 g·L^(-1)),heart rate and cardiac output of isolated frog heart were studied.Acetylcholine,atropine and epinephrine were administered successively to analyze the effects of Xindakang on cardiac systolic function of isolated frogs under the action of different drugs,and compared with propranolol.The effect of extracellular calcium ion concentration on the action of Xindakang was studied by using low calcium concentration,high calcium concentration and normal Ren′s solution.To study the effect and possible mechanism of Xindakang on cardiac systolic function of frog.RESULTS The concentration of Xindakang in the range of 0.0125-0.1 g·L^(-1)could weaken the contractility of isolated frog heart and increase the concentration of Xindakang.The inhibitory effect of Xindakang on contractility of isolated frog heart was enhanced,and showed obvious dose-effect relationship.Cardiac output was significantly decreased by Xindakang(P<0.01),slow heart rate(P<0.05);M receptor blocker atropine could not antagonize the contractile effect of Xindakang,and Xindakang could not completely antagonize the contractile effect of adrenalin.Xindakang could inhibit the isolated frog heart in low calcium concentration,high calcium concentration and normal Ren′s solution,and increased with the increase of extracellular calcium concentration(P<0.01).CONCLUSION Xindakang has inhibitory effect on isolated frog heart,which may be achieved by blocking the calcium channel on myocardial cell membrane and reducing the calcium concentration in myocardial cells.
基金Projects(51978222,51722805,U2106222) supported by the National Natural Science Foundation of ChinaProject(HIT.BRETIV 201803) supported by the Fundamental Research Funds for the Central Universities,China。
文摘An isolated slit was placed in a single box girder to obtain passive leading-edge suction and trailing-edge jet flow to control the unsteady aerodynamic force and modify the flow structure.The Great Belt East Bridge was used as a physical model at a geometric scale of 1:125.Wind tunnel experiments were conducted at an incoming airflow speed of 10 m/s,and the Reynolds number was calculated as 2.3×104 using the test model height and wind speed.The surface pressure distribution was measured,and the aerodynamic force acting on the test model with and without the isolated slit was calculated by integrating the pressure result.It was found that the control using an isolated slit can dramatically decrease the fluctuating surface pressure distribution and aerodynamic force.An analysis on the power spectral density of the lift force revealed that the isolated slit accelerated vortex shedding.Moreover,high-speed particle image velocimetry was used to investigate the wake flow structure behind the test model.A vortex separated from the upper surface was pushed to a lower location and the wake flow structure was modified by the isolated slit.A proper orthogonal decomposition(POD)of the flow field showed that the first two POD modes in the controlled case contributed less energy than those in the uncontrolled case,indicating that more energy was transferred to higher modes,and small-scale vortices had more energy.A secondary instability structure was found in the wake flow for a nondimensional jet momentum coefficient J of 0.0667.
文摘The plant pathogen Verticillium dahliae causes severe cotton losses in Uzbekistan. To create cotton varieties that are resistant to the more virulent races of V.dahliae we wanted to determine
基金Supported by the Youth Foundation of College of Resources and Environment of Northeast Agricultural University
文摘A novel method isolated microorganisms in soil granule was built. The key steps included： repeated elutriation of soil by sterilized water, inoculation on the plates with the elutriated sediments, incubation of the plates and isolation of the actinomycetes by using selected culture medium. We formulated that most microflora included the dominant actinomycetes in the soil were carried away with the sterilized water in the elutriation procedure, some rare actinomycetes and few other microflora included bacteria were remained in the elutriated sediments, the other microflora were excluded to grew into colonies on the plates by using selective culture medium for actinomycetes in the elutriated sediments. Results showed the supposition. Non-streptomycete actinomycetes were isolated both from black soil samples from Chinese northeast area and compost samples from Chinese central area. Soil fungi in granule were isolated by using the selective conditions to favor fungi. The results showed that the method was effective
基金supported by the National Natural Science Foundation of China (Grant No. 12202204)the Natural Science Foundation of Jiangsu Province (Grant No. BK20220953)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Science and Technology Association's Young Talent Nurturing Program of Jiangsu Province (Grant No. JSTJ-2024-004)
文摘In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The effects of the divergence, straight, and convergence isolators on the rotating detonation wave dynamics and the upstream oblique shock wave propagation mechanism are analyzed. The differences in the rotating detonation wave behaviors between ground and flight operations are clarified.The results indicate that the propagation regimes of the upstream oblique shock wave depend on the isolator configurations and operation conditions. With a divergence isolator, the airflow is accelerated throughout the isolator and divergence section, leading to a maximum Mach number(~1.8) before the normal shock. The total pressure loss reaches the largest, and the detonation pressure drops. The upstream oblique shock wave can be suppressed within the divergence section with the divergence isolator.However, for the straight and convergence isolators, the airflow in the isolator with a larger ψ_(1)(0.3 and0.4) can suffer from the disturbance of the upstream oblique shock wave. The critical incident angle is around 39° at ground operation conditions. The upstream oblique shock wave tends to be suppressed when the engine operates under flight operation conditions. The critical pressure ratio β_(cr0) is found to be able to help in distinguishing the propagation regimes of the upstream oblique shock wave. Slightly below or above the β_(cr0) can obtain different marginal propagation results. The high-speed airflow in the divergence section affects the fuel droplet penetration distance, which deteriorates the reactant mixing and the detonation area. Significant detonation velocity deficits are observed and the maximum velocity deficit reaches 26%. The results indicate the engine channel design should adopt different isolator configurations based on the purpose of total pressure loss or disturbance suppression. This study can provide useful guidance for the channel design of a more complete two-phase rotating detonation engine.
基金supported by Biological Breeding of Early Maturing and Disease Resistant Cotton Varieties (NO.2023ZD04041)the Project of China Agriculture Research System (Grant No. CARS-15-06)+2 种基金Natural Science Foundation of Henan Province (Grant No. 232300421041 and 222300420382)National Natural Science Foundation of China (Grant No. U21 A20213)the Central Public-interest Scientific Institution Basal Research Fund (Grant No. 1610162023017 and 1610162023028)。
文摘Background Cotton is an important crop providing the most natural fibers all over the world. The cotton genomics community has utilized whole genome sequencing data to construct an elite gene pool in which functional genes are related to agronomic traits. However, the functional validation of these genes is hindered by time-consuming and inefficient genetic transformation methods. Thus, establishing a transient transformation system of high efficiency is necessary for cotton genomics.Results To improve the efficiency of transient transformation, we used the protoplasts isolated from the etiolated cotyledon as recipient. The enzymatic digestion buffer comprised 1.5%(w/v) cellulase, 0.75%(w/v) macerozyme, and 1% hemicellulase, osmotically buffered with 0.4 mol·L^(-1) mannitol. After 5 h of dark incubation at 25℃, uniform cotton protoplasts were successfully isolated with a yield of 4.6 × 10^(6) protoplasts per gram(fresh weight) and 95% viability. We incubated 100 μL protoplasts(2.5 × 10^(5)·m L^(-1)) with 15 μg plasmid in the solution of 0.4 mol·L^(-1) mannitol and 40% PEG 4000 for 15 min, ultimately achieving an optimal transient transfection efficiency of 71.47%.Conclusions This transient system demonstrated effective utility in cellular biology research through successful applications in subcellular localization analyses, bimolecular fluorescence complementation(Bi FC) verification, and prime editing vector validation. Through systematic optimization, we established an efficient and expedited protoplast-based transient transformation system and successfully applied this platform to cotton functional genomics studies.
基金supported by the Shanxi Provincial Natural Science Basic Research Program Young Talent Project(S2019-JC-QN-2408).
文摘The process of ground vehicle dynamic gravimetry is inevitably affected by the carrier’s maneuvering acceleration,which makes the result contain a large amount of dynamic error.In this paper,we propose a dynamic error suppression method of gravimetry based on the high-precision acquisition of external velocity for compensating the horizontal error of the inertial plat-form.On the basis of platform gravity measurement,firstly,the dynamic performance of the system is enhanced by optimizing the horizontal damping network of the inertial platform and selecting its parameter.Secondly,an improved federal Kalman filtering algorithm and a fault diagnosis method are designed using strapdown inertial navigation system(SINS),odometer(OD),and laser Doppler velocimeter(LDV).Simulation validates that these methods can improve the accuracy and robustness of the external velocity acquisition.Three survey lines are selected in Tianjin,China,for the gravimetry experiments with different maneuvering levels,and the results demonstrate that after dynamic error suppression,the internal coincidence accuracies of smooth and uniform operation,obvious acceleration and deceleration operation,and high-dynamic operation are improved by 70.2%,73.6%,and 77.9%to reach 0.81 mGal,1.30 mGal,and 1.94 mGal,respectively,and the external coinci-dence accuracies during smooth and uniform operation are improved by 48.6%up to 1.66 mGal.It is shown that the pro-posed method can effectively suppress the dynamic error,and that the accuracy improvement increases with carrier maneuver-ability.However,the amount of residual error that can not be entirely eliminated increases as well,so the ground vehicle dynamic gravimetry should be maintained in the carrier for smooth and uniform operation.
基金Project(51978585)supported by the National Natural Science Foundation,ChinaProject(2022YFB2603404)supported by the National Key Research and Development Program,China+1 种基金Project(U1734207)supported by the High-speed Rail Joint Fund Key Projects of Basic Research,ChinaProject(2023NSFSC1975)supported by the Sichuan Nature and Science Foundation Innovation Research Group Project,China。
文摘The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.
文摘High-static-low-dynamic stiffness (HSLDS) vibration isolators have been demonstrated to be an effective means of attenuating low-frequency vibrations, and may be utilized for ship shafting applications to mitigate torsional vibration. This paper presents the construction of a highly compact HSLDS torsional vibration isolator by connecting positive and negative stiffness components in paral lel. Based on mechanical model analysis, the restoring torque of negative stiffness components is de rived from their springs and connecting rods, while that of positive stiffness components is obtained through their circular section flexible rods. The quasizero stiffness characteristics of the HSLDS iso lator are achieved through a combination of static structural simulation and experimental test. The tor sional vibration isolation performance is assessed by means of numerical simulation and theory analy sis. Finally, the frequency-sweep vibration test is conducted. The test results indicate that the HSLDS torsional vibration isolator exhibits superior low-frequency isolation performance compared to its linear counterpart, rendering it a promising solution for mitigating low-frequency torsional vi bration in ship shafting.
文摘利用FIASCO(Fast Isolation by AFLP Sequences Containing repeats)技术建立拟穴青蟹Scylla paramamosain基因组文库,并与生物素标记的(CA)15寡核苷酸探针杂交,联合磁珠富集法构建拟穴青蟹微卫星富集文库。测序194个阳性菌落,分析其中的150条序列,结果表明:两碱基重复类型占90%以上,其中重复拷贝数在30以上的占27.45%;含微卫星座位189个,其中完美型146个、非完美型28个和复合型15个。设计125对引物扩增一个拟穴青蟹野生群体(含20个个体),其中的19对引物能稳定扩增且片段大小基本符合理论长度。遗传变异分析表明,17个位点表现出高度多态性,16个位点显著偏离Hardy-Weinberg平衡(P<0.05),4组两两位点间存在连锁不平衡现象(P<0.0026,经Bonferroni法校正),7个微卫星位点可能存在无效等位基因。若排除混合微卫星位点的引物对以及扩增位点PIC(polymorphism information content)值在0.5以下的引物对,则13对引物能用于拟穴青蟹群体遗传学等研究。
文摘Our current project is to isolate,identify andcharacterize cotton fiber-specific genes in orderto pick up candidates for fiber qualityimprovement.Firstly,10DPA(day postanthesis)cotton fiber cDNA library wasconstructed with 5X106 primary titer and 1.
文摘Based on the numerical simulation of solidification, a computer aid design(CAD) software package of casting technique was developed to design the rising system intelligently. The software can calculate the size and locate the situations of the isolated melts. According to the liquid shrinkage of each isolated melts and the standard parameters of risers in the database, the riser’s situation and the size can be identified intelligently as long as the riser’s shape is selected. 3-D software and simulation analysis of CAST soft/computer aid engineering(CAE) software show that the design of the riser and the running system is feasible.
基金State Tobacco Monopoly Administration of China (110200201008)
文摘The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.
