Plants develop important regulatory networks to adapt to the frequently-changing availability of copper （Cu）, However, little is known about miRNA-associated Cu-regulatory networks in plant species other than Arabid...Plants develop important regulatory networks to adapt to the frequently-changing availability of copper （Cu）, However, little is known about miRNA-associated Cu-regulatory networks in plant species other than Arabidopsis. Here, we report that Cu-responsive miRNAs in Populus trichocarpa （Torr. ＆ Gray） include not only conserved miR397, miR398 and miR408, but also Populus-specific miR1444, suggesting the conservation and diversity of Cu-responsive miRNAs in plants. Copper-associated suppression of mature miRNAs is in company with the up-regulation of their target genes encoding Cu-containing proteins in Populus. The targets include miR397-targeted PtLAC5, PtLAC6 and PtLAC110a, miR398- targeted PtCSD1, PtCSD2a and PtCSD2b, miR408-targeted PtPCL1, PtPCL2, PtPCL3 and PtLAC4, and miR1444-targeted PtPP03 and PtPP06. Consistently, P. trichocarpa miR408 promoter-directed GUS gene expression is down-regulated by Cu in transgenic tobacco plants. Cu-response elements （CuREs） are found in the promoters of Cu-responsive miRNA genes. We identified 34 SQUAMOSA-promoter binding protein-like （SPL） genes, of which 17 are full-length PtSPL proteins or partial sequences with at least 300 amino acids. Phylogenetic analysis indicates that PtSPL3 and PtSPL4 are CuRE-binding proteins controlling Cu-responsive gene expression. Cu appears to be not involved in the regulation of these transcription factors because neither PtSPL3 nor PtSPL4 is Cu-regulated and no CuRE exists in their promoters.展开更多
With the Zebiak-Cane model and a parameterized stochastic representation of intraseasonal forcing, the impact of the uncertainties of Madden Jullian Oscillation （MJO） on the ＂Spring Predictability Barrier （SPB）＂...With the Zebiak-Cane model and a parameterized stochastic representation of intraseasonal forcing, the impact of the uncertainties of Madden Jullian Oscillation （MJO） on the ＂Spring Predictability Barrier （SPB）＂ for El Nifio-Southern Oscillation （ENSO） prediction is studied. The parameterized form of MJO forcing is added physically to the Zebiak-Cane model to obtain the so-called Zebiak-Cane-MJO model and then the effects of initial error, stochastic model error, and their joint error mode on the SPB associated with El Nifio prediction are estimated. The results show that the model errors caused by stochastic MJO forcing could hardly lead to a significant SPB while initial errors can do; furthermore, the joint error mode of initial error and model error associated with the stochastic MJO forcing can also lead to a significant SPB. These demonstrate that the initial error is probably the main error source of the SPB, which may provide a theoretical foundation of data assimilation for ENSO forecasts.展开更多
Spherical polyelectrolyte brushes （SPBs） with PS core and poly（acrylic acid） （PAA） brushes were prepared and analyzed by SAXS in this article. A radial electron density profile of SPB was brought up, which fits ...Spherical polyelectrolyte brushes （SPBs） with PS core and poly（acrylic acid） （PAA） brushes were prepared and analyzed by SAXS in this article. A radial electron density profile of SPB was brought up, which fits well with the SAXS result and shows a core-shell structure. The effect of pH on SPB form was represented by SAXS and it proves that the chains of SPB will stretch in response to increased pH owning to the increased electrostatic repulsion. SPBs immobilized with magnetic nanoparticles or bovine serum albumin （BSA） were prepared and analyzed by SAXS as well. SAXS could characterize the changes of electron density inside brushes of SPBs due to the immobilization of magnetic nanoparticles or BSA. This provides significant supports for further application of immobilized metal nanoparticles or proteins.展开更多
Based on load separation theory, the load separation parameter Spb method is an effective approach for estimating the J-resistance curve from records of load versus displacement directly, using one sharp cracked speci...Based on load separation theory, the load separation parameter Spb method is an effective approach for estimating the J-resistance curve from records of load versus displacement directly, using one sharp cracked specimen and an additional reference blunt cracked specimen. However, the effect of the reference blunt cracked specimen on J-resistance determination was not explicitly considered in past work. In this paper, a modified load separation parameter Spb method was developed to eliminate this effect, and then a unique estimation of instantaneous crack length for one sharp cracked specimen could be obtained. Furthermore, a forced blunting calibration method was also adopted to determine the instantaneous crack length in the load inseparable region, referring to a normalization method. Experiments on steam turbine rotator steel Cr2Ni2MoV were carried out to estimate J-resistance curves using an unloading compliance method. By removing unload and reload data from load-displacement records, the J-resistance curve for the same sharp cracked specimen was estimated using the modified separation parameter Spb method. The results indicate that the modified Spb method completely eliminates the effect of the reference blunt cracked specimen on the instantaneous crack length determination of the sharp cracked specimen. However, different J-resistance curves in a small range of crack extension are present when different blunting coefficients are used in the blunting line equation. The J-resistance curve obtained from the modified Spb method agrees well with that obtained from the compliance method.展开更多
The spectral energy distribution(SED) of TeV blazars has a double-humped shape that is usually interpreted as a Synchrotron Self Compton(SSC) model.The one zone SSC model is used broadly but cannot fit the high energy...The spectral energy distribution(SED) of TeV blazars has a double-humped shape that is usually interpreted as a Synchrotron Self Compton(SSC) model.The one zone SSC model is used broadly but cannot fit the high energy tail of SED very well.It needs a bulk Lorentz factor which is in conflict with the observation.Furthermore,a one zone SSC model cannot explain the entire spectrum.We propose a new model where the high energy emission is produced by the accelerated protons in the blob with a small size and high magnetic field,and the low energy radiation comes from the electrons in the expanded blob.Because the high and low energy photons are not produced at the same time,the requirement of a large Doppler factor from pair production is relaxed.We present the fitting results of the SEDs for Mrk 501 during April 1997 and Mrk 421 during March 2001.展开更多
Semiconducting cubic group IV monotellurides,including PbTe and SnTe, have historically led most of the advancements in thermoelectrics. Recently, noncubic ones such as GeTe and MnTe have also shown to be promising,wh...Semiconducting cubic group IV monotellurides,including PbTe and SnTe, have historically led most of the advancements in thermoelectrics. Recently, noncubic ones such as GeTe and MnTe have also shown to be promising,which motivates the current work focusing on the thermoelectric properties of MnGeTe2, a derivative compound of noncubic GeTe and MnTe but crystalizing in a cubic structure.This compound intrinsically comes with a carrier concentration as high as ~3.6×1021 cm-3, indicating the existence of highconcentration cation vacancies due to Ge-precipitation. This intrinsic carrier concentration is much higher than that needed for thermoelectric applications but can be successfully decreased to ~9×1020 cm-3 for MnGe0.9Bi0.1Te2 at room temperature. Such a broad carrier concentration not only offers a full assessment of its electronic transport properties according to a single parabolic band model with acoustic scattering, but also enables an optimization for thermoelectric power factor.The low lattice thermal conductivity of ~1.2 W m-1 K-1 or lower in the entire temperature range, can be understood by the highly disordered cations and cation vacancies. A peak zT approaching 1.0 at 850 K was achieved in materials at an optimal carrier concentration of ~9×1020 cm-3, an isotropic cubic structure as well as a Vickers hardness of >200 HV, strongly indicating MnGeTe2 as a promising thermoelectric material.展开更多
孤立性骨浆细胞瘤(solitary plasmacytoma of bone,SPB)指在没有多发性骨髓瘤其他特征的情况下由浆细胞的单个克隆组成的局部肿瘤[1]。发生在脊柱的SPB发病率低,起病隐匿,首发症状是病椎附近的局部疼痛,多为隐痛,逐渐加重至难以忍受的剧...孤立性骨浆细胞瘤(solitary plasmacytoma of bone,SPB)指在没有多发性骨髓瘤其他特征的情况下由浆细胞的单个克隆组成的局部肿瘤[1]。发生在脊柱的SPB发病率低,起病隐匿,首发症状是病椎附近的局部疼痛,多为隐痛,逐渐加重至难以忍受的剧痛,多数患者因病灶侵犯脊髓或神经根出现神经症状就诊,严重可致脊柱病理骨折,早期表现无特异性,诊断困难。展开更多
基金supported by the Forest Biotech-nology Industrial Research Consortium at North Carolina State University, USAthe National High-Tech Research and Development Program (863 Program) of China (2009AA10Z101)+1 种基金the National Natural Science Foundation of China (31070534)the Program for Xiehe Scholars in the Chinese Academy of Medical Sciences & Peking Union Medical College
文摘Plants develop important regulatory networks to adapt to the frequently-changing availability of copper （Cu）, However, little is known about miRNA-associated Cu-regulatory networks in plant species other than Arabidopsis. Here, we report that Cu-responsive miRNAs in Populus trichocarpa （Torr. ＆ Gray） include not only conserved miR397, miR398 and miR408, but also Populus-specific miR1444, suggesting the conservation and diversity of Cu-responsive miRNAs in plants. Copper-associated suppression of mature miRNAs is in company with the up-regulation of their target genes encoding Cu-containing proteins in Populus. The targets include miR397-targeted PtLAC5, PtLAC6 and PtLAC110a, miR398- targeted PtCSD1, PtCSD2a and PtCSD2b, miR408-targeted PtPCL1, PtPCL2, PtPCL3 and PtLAC4, and miR1444-targeted PtPP03 and PtPP06. Consistently, P. trichocarpa miR408 promoter-directed GUS gene expression is down-regulated by Cu in transgenic tobacco plants. Cu-response elements （CuREs） are found in the promoters of Cu-responsive miRNA genes. We identified 34 SQUAMOSA-promoter binding protein-like （SPL） genes, of which 17 are full-length PtSPL proteins or partial sequences with at least 300 amino acids. Phylogenetic analysis indicates that PtSPL3 and PtSPL4 are CuRE-binding proteins controlling Cu-responsive gene expression. Cu appears to be not involved in the regulation of these transcription factors because neither PtSPL3 nor PtSPL4 is Cu-regulated and no CuRE exists in their promoters.
基金Supported by Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-QN203)National Basic Research and Development (973) Program of China (2010CB950400 and 2012CB955202)National Natural Science Foundation of China (41176013)
文摘With the Zebiak-Cane model and a parameterized stochastic representation of intraseasonal forcing, the impact of the uncertainties of Madden Jullian Oscillation （MJO） on the ＂Spring Predictability Barrier （SPB）＂ for El Nifio-Southern Oscillation （ENSO） prediction is studied. The parameterized form of MJO forcing is added physically to the Zebiak-Cane model to obtain the so-called Zebiak-Cane-MJO model and then the effects of initial error, stochastic model error, and their joint error mode on the SPB associated with El Nifio prediction are estimated. The results show that the model errors caused by stochastic MJO forcing could hardly lead to a significant SPB while initial errors can do; furthermore, the joint error mode of initial error and model error associated with the stochastic MJO forcing can also lead to a significant SPB. These demonstrate that the initial error is probably the main error source of the SPB, which may provide a theoretical foundation of data assimilation for ENSO forecasts.
基金financially supported by the National Natural Science Foundation of China(No.20774028)the Fundamental Research Funds for the Central Universities+1 种基金the Higher School Specialized Research Fund for the doctoral program(20110074110003)Shanghai Synchrotron Radiation Facility
文摘Spherical polyelectrolyte brushes （SPBs） with PS core and poly（acrylic acid） （PAA） brushes were prepared and analyzed by SAXS in this article. A radial electron density profile of SPB was brought up, which fits well with the SAXS result and shows a core-shell structure. The effect of pH on SPB form was represented by SAXS and it proves that the chains of SPB will stretch in response to increased pH owning to the increased electrostatic repulsion. SPBs immobilized with magnetic nanoparticles or bovine serum albumin （BSA） were prepared and analyzed by SAXS as well. SAXS could characterize the changes of electron density inside brushes of SPBs due to the immobilization of magnetic nanoparticles or BSA. This provides significant supports for further application of immobilized metal nanoparticles or proteins.
基金Project (No 11072205) supported by the National Natural Science Foundation of China
文摘Based on load separation theory, the load separation parameter Spb method is an effective approach for estimating the J-resistance curve from records of load versus displacement directly, using one sharp cracked specimen and an additional reference blunt cracked specimen. However, the effect of the reference blunt cracked specimen on J-resistance determination was not explicitly considered in past work. In this paper, a modified load separation parameter Spb method was developed to eliminate this effect, and then a unique estimation of instantaneous crack length for one sharp cracked specimen could be obtained. Furthermore, a forced blunting calibration method was also adopted to determine the instantaneous crack length in the load inseparable region, referring to a normalization method. Experiments on steam turbine rotator steel Cr2Ni2MoV were carried out to estimate J-resistance curves using an unloading compliance method. By removing unload and reload data from load-displacement records, the J-resistance curve for the same sharp cracked specimen was estimated using the modified separation parameter Spb method. The results indicate that the modified Spb method completely eliminates the effect of the reference blunt cracked specimen on the instantaneous crack length determination of the sharp cracked specimen. However, different J-resistance curves in a small range of crack extension are present when different blunting coefficients are used in the blunting line equation. The J-resistance curve obtained from the modified Spb method agrees well with that obtained from the compliance method.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10673028 and 10778702)the National Basic Research Program of China (Grant No. 2009CB824800)
文摘The spectral energy distribution(SED) of TeV blazars has a double-humped shape that is usually interpreted as a Synchrotron Self Compton(SSC) model.The one zone SSC model is used broadly but cannot fit the high energy tail of SED very well.It needs a bulk Lorentz factor which is in conflict with the observation.Furthermore,a one zone SSC model cannot explain the entire spectrum.We propose a new model where the high energy emission is produced by the accelerated protons in the blob with a small size and high magnetic field,and the low energy radiation comes from the electrons in the expanded blob.Because the high and low energy photons are not produced at the same time,the requirement of a large Doppler factor from pair production is relaxed.We present the fitting results of the SEDs for Mrk 501 during April 1997 and Mrk 421 during March 2001.
基金supported by the National Natural Science Foundation of China (11474219 and 51772215)the National Key Research and Development Program of China (2018YFB0703600)+3 种基金the Fundamental Research Funds for Science and Technology Innovation Plan of Shanghai (18JC1414600)Fok Ying Tung Education Foundation (20170072210001)"Shu Guang" Project Supported by Shanghai Municipal Education CommissionShanghai Education Development Foundation
文摘Semiconducting cubic group IV monotellurides,including PbTe and SnTe, have historically led most of the advancements in thermoelectrics. Recently, noncubic ones such as GeTe and MnTe have also shown to be promising,which motivates the current work focusing on the thermoelectric properties of MnGeTe2, a derivative compound of noncubic GeTe and MnTe but crystalizing in a cubic structure.This compound intrinsically comes with a carrier concentration as high as ~3.6×1021 cm-3, indicating the existence of highconcentration cation vacancies due to Ge-precipitation. This intrinsic carrier concentration is much higher than that needed for thermoelectric applications but can be successfully decreased to ~9×1020 cm-3 for MnGe0.9Bi0.1Te2 at room temperature. Such a broad carrier concentration not only offers a full assessment of its electronic transport properties according to a single parabolic band model with acoustic scattering, but also enables an optimization for thermoelectric power factor.The low lattice thermal conductivity of ~1.2 W m-1 K-1 or lower in the entire temperature range, can be understood by the highly disordered cations and cation vacancies. A peak zT approaching 1.0 at 850 K was achieved in materials at an optimal carrier concentration of ~9×1020 cm-3, an isotropic cubic structure as well as a Vickers hardness of >200 HV, strongly indicating MnGeTe2 as a promising thermoelectric material.
文摘孤立性骨浆细胞瘤(solitary plasmacytoma of bone,SPB)指在没有多发性骨髓瘤其他特征的情况下由浆细胞的单个克隆组成的局部肿瘤[1]。发生在脊柱的SPB发病率低,起病隐匿,首发症状是病椎附近的局部疼痛,多为隐痛,逐渐加重至难以忍受的剧痛,多数患者因病灶侵犯脊髓或神经根出现神经症状就诊,严重可致脊柱病理骨折,早期表现无特异性,诊断困难。
