应用基于气相色谱-质谱联用(GC-MS)的代谢组学方法结合细胞周期实验,研究羽扇豆醇体外抑制人乳腺癌细胞MCF-7增殖的作用机理。代谢组学的研究结果表明:通过正交偏最小方差判别分析(OPLS-DA)可以很好地区分羽扇豆醇作用的MCF-7细胞代谢...应用基于气相色谱-质谱联用(GC-MS)的代谢组学方法结合细胞周期实验,研究羽扇豆醇体外抑制人乳腺癌细胞MCF-7增殖的作用机理。代谢组学的研究结果表明:通过正交偏最小方差判别分析(OPLS-DA)可以很好地区分羽扇豆醇作用的MCF-7细胞代谢谱与对照组细胞代谢谱,模型参数为:R2 Ycum=0.988,Q2 Ycum=0.964。VIP(variable importance in the projection)值大于1的差异代谢物进一步用t检验进行单位分析,选择t<0.05(VIP>1)的代谢物作为羽扇豆醇作用组的生物标志物,得到琥珀酸、磷酸、亮氨酸、异亮氨酸等11种代谢差异物。结合羽扇豆醇将细胞周期抑制在G1期这一现象,推测羽扇豆醇可能是主要抑制了三羧酸循环中的琥珀酰辅酶A的生成和底物磷酸化生成ATP的反应来抑制MCF-7细胞的增殖。本实验从代谢组学角度为乳腺癌抗肿瘤机制提供新的线索。展开更多
In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were appli...In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were applied to study optimization design of herringbone multilateral well.According to the characteristics of herringbone multilateral well,by using pressure superposition and mirror image reflection theory,the coupled model of herringbone multilateral well was developed on the basis of a three-dimensional pseudo-pressure distribution model for horizontal wells.The model was formulated in consideration of friction loss,acceleration loss of the wellbore and mixed loss at the confluence of main wellbore and branched one.After mathematical simulation on productivity of the herringbone multilateral well with the coupled model,the effects of well configuration on productivity were analyzed.The results show that lateral number is the most important factor,length of main wellbore and length of branched wellbore are the secondary ones,angle between main and branched one has the least influence.展开更多
This paper proposes a subspace-based noise variance and Signal-to-Noise Ratio (SNR) estimation algorithm for Multi-Input Multi-Output (MIMO) wireless Orthogonal Frequency Division Multiplexing (OFDM) systems. The spec...This paper proposes a subspace-based noise variance and Signal-to-Noise Ratio (SNR) estimation algorithm for Multi-Input Multi-Output (MIMO) wireless Orthogonal Frequency Division Multiplexing (OFDM) systems. The special training sequences with the property of orthogonality and phase shift orthogonality are used in pilot tones to obtain the estimated channel correlation matrix. Partitioning the observation space into a delay subspace and a noise subspace, we achieve the measurement of noise variance and SNR. Simulation results show that the proposed estimator can obtain accurate and real-time measurements of the noise variance and SNR for various multipath fading channels, demonstrating its strong robustness against different channels.展开更多
The turbo equalization approach is studied for Orthogonal Frequency Division Multiplexing （OFDM） system with combined error control coding and linear precoding. While previous literatures employed linear precodcr of...The turbo equalization approach is studied for Orthogonal Frequency Division Multiplexing （OFDM） system with combined error control coding and linear precoding. While previous literatures employed linear precodcr of small size for complexity reasons, this paper proposes to use a linear precoder of size larger than or equal to the maximum length of the equivalent discrete-time channel in order to achieve full frequency diversity and reduce complexities of the error control coder/decoder. Also a low complexity Linear Minimum Mean Square Error （LMMSE） turbo equalizer is derived for the receiver. Through simulation and performance analysis, it is shown that the performance of the proposed scheme over frequency selective fading channel reaches the matched filter bound; compared with the same coded OFDM without linear precoding, the proposed scheme shows an Signal-to-Noise Ratio （SNR） improvement of at least 6dB at a bit error rate of 10 6 over a multipath channel with exponential power delay profile. Convergence behavior of the proposed scheme with turbo equalization using various type of linear precoder/transformer, various interleaver size and error control coder of various constraint length is also investigated.展开更多
Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numeri...Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numerical solutions of the governing equations of unsteady two-dimensional flow of a polytropic gas are investigated. The numerical results reveal that the new technique is very effective and gives high accuracy, good convergence and reasonable stability.展开更多
This paper studies the influence of a stress relaxation zone caused by foundation excavation on the performance of Jinping-I arch dam, using the orthogonal experiment method. Firstly, by adopting the characteristic st...This paper studies the influence of a stress relaxation zone caused by foundation excavation on the performance of Jinping-I arch dam, using the orthogonal experiment method. Firstly, by adopting the characteristic stress of the dam as an index and coupling it with range analysis, the most significant factors and the degree of relaxation influence on the arch dam performance are found. This is then combined with monitoring data from the dam, and the extent of influence on the arch dam performance caused by the relaxation is evaluated through numerical analysis. The results show that the relaxation of foundation excavation has a negative impact on the performance of the arch dam in general, the extent of elastic modulus degradation in the relaxation zone being the main factor affecting stresses in the dam. The relaxation of the rock mass leads to an increase in dam stress in local areas near the relaxation zone, but has little effect on more distant areas.展开更多
文摘应用基于气相色谱-质谱联用(GC-MS)的代谢组学方法结合细胞周期实验,研究羽扇豆醇体外抑制人乳腺癌细胞MCF-7增殖的作用机理。代谢组学的研究结果表明:通过正交偏最小方差判别分析(OPLS-DA)可以很好地区分羽扇豆醇作用的MCF-7细胞代谢谱与对照组细胞代谢谱,模型参数为:R2 Ycum=0.988,Q2 Ycum=0.964。VIP(variable importance in the projection)值大于1的差异代谢物进一步用t检验进行单位分析,选择t<0.05(VIP>1)的代谢物作为羽扇豆醇作用组的生物标志物,得到琥珀酸、磷酸、亮氨酸、异亮氨酸等11种代谢差异物。结合羽扇豆醇将细胞周期抑制在G1期这一现象,推测羽扇豆醇可能是主要抑制了三羧酸循环中的琥珀酰辅酶A的生成和底物磷酸化生成ATP的反应来抑制MCF-7细胞的增殖。本实验从代谢组学角度为乳腺癌抗肿瘤机制提供新的线索。
基金Project(12521044) supported by Scientific and Technological Research Program of Heilongjiang Provincial Education Department,China
文摘In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were applied to study optimization design of herringbone multilateral well.According to the characteristics of herringbone multilateral well,by using pressure superposition and mirror image reflection theory,the coupled model of herringbone multilateral well was developed on the basis of a three-dimensional pseudo-pressure distribution model for horizontal wells.The model was formulated in consideration of friction loss,acceleration loss of the wellbore and mixed loss at the confluence of main wellbore and branched one.After mathematical simulation on productivity of the herringbone multilateral well with the coupled model,the effects of well configuration on productivity were analyzed.The results show that lateral number is the most important factor,length of main wellbore and length of branched wellbore are the secondary ones,angle between main and branched one has the least influence.
基金Supported by the National Natural Science Foundation of China(No.60496311)
文摘This paper proposes a subspace-based noise variance and Signal-to-Noise Ratio (SNR) estimation algorithm for Multi-Input Multi-Output (MIMO) wireless Orthogonal Frequency Division Multiplexing (OFDM) systems. The special training sequences with the property of orthogonality and phase shift orthogonality are used in pilot tones to obtain the estimated channel correlation matrix. Partitioning the observation space into a delay subspace and a noise subspace, we achieve the measurement of noise variance and SNR. Simulation results show that the proposed estimator can obtain accurate and real-time measurements of the noise variance and SNR for various multipath fading channels, demonstrating its strong robustness against different channels.
基金Supported by the National High Technology ResearchDevelopment Program of China (863 Program)(No.2001AA 123014)
文摘The turbo equalization approach is studied for Orthogonal Frequency Division Multiplexing （OFDM） system with combined error control coding and linear precoding. While previous literatures employed linear precodcr of small size for complexity reasons, this paper proposes to use a linear precoder of size larger than or equal to the maximum length of the equivalent discrete-time channel in order to achieve full frequency diversity and reduce complexities of the error control coder/decoder. Also a low complexity Linear Minimum Mean Square Error （LMMSE） turbo equalizer is derived for the receiver. Through simulation and performance analysis, it is shown that the performance of the proposed scheme over frequency selective fading channel reaches the matched filter bound; compared with the same coded OFDM without linear precoding, the proposed scheme shows an Signal-to-Noise Ratio （SNR） improvement of at least 6dB at a bit error rate of 10 6 over a multipath channel with exponential power delay profile. Convergence behavior of the proposed scheme with turbo equalization using various type of linear precoder/transformer, various interleaver size and error control coder of various constraint length is also investigated.
文摘Aims of this paper are to improve ADI differential quadrature method （ADI-DQM） based on Bernstein polynomials and add a new application to the differential quadrature method. By using the new methodology, the numerical solutions of the governing equations of unsteady two-dimensional flow of a polytropic gas are investigated. The numerical results reveal that the new technique is very effective and gives high accuracy, good convergence and reasonable stability.
基金supported by the National Basic Research Program of China (Grant No. 2007CB714104)the National Natural Science Founda-tion of China (Grant No. 51079045)
文摘This paper studies the influence of a stress relaxation zone caused by foundation excavation on the performance of Jinping-I arch dam, using the orthogonal experiment method. Firstly, by adopting the characteristic stress of the dam as an index and coupling it with range analysis, the most significant factors and the degree of relaxation influence on the arch dam performance are found. This is then combined with monitoring data from the dam, and the extent of influence on the arch dam performance caused by the relaxation is evaluated through numerical analysis. The results show that the relaxation of foundation excavation has a negative impact on the performance of the arch dam in general, the extent of elastic modulus degradation in the relaxation zone being the main factor affecting stresses in the dam. The relaxation of the rock mass leads to an increase in dam stress in local areas near the relaxation zone, but has little effect on more distant areas.
