Application of nitrogen (N) fertilizer is one of the most important approaches on improving maize grain yield. However, as is known to all, overuse N fertilizer not only leads to decline of N use efficiency and maize ...Application of nitrogen (N) fertilizer is one of the most important approaches on improving maize grain yield. However, as is known to all, overuse N fertilizer not only leads to decline of N use efficiency and maize yield, but also leads to potential risk to environment pollution. This experiment was conducted to determine the effects of N fertilizer applications with nine different treatments on soil physical-chemical characters and maize grain yield using hybrid variety Zhengdan 958 in 2011 and 2012. Results indicated that the soil bulk densities of T2 (CK) and T1 were the lowest compared to other treatments in 2011 and 2012, respectively, whereas the soil bulk density of T5 in 2011 and T3 in 2012 were higher than other treatments. The soil porosity and field capacity of T5 in 2011 and T3 in 2012 were lower than other treatments, but those of CK in 2011 and T1 in 2012 were higher than other treatments. The pH values of T3 to T7 were lower than other treatments. These results indicated that the soil bulk densities were increased, whereas the soil porosity, field capacity and values pH were decreased by N application at different stages. N application could increase the N contents of leaf and stem, whereas less or excess N application should not significant improve maize yield. Although the soil organic matter and total N contents of T3 were the highest in both 2011 and 2012, the yield of T4 is the highest in both 2011 and 2012. The application amount, period and times of N fertilizer were important to maize yield.展开更多
T-wave alternans(TWA)refers to the periodic beat-to-beat variation in the amplitude of T-wave in the electrocardiogram(ECG)signal in an ABAB-pattern.TWA has been proven to be a very important indicator of malignant ar...T-wave alternans(TWA)refers to the periodic beat-to-beat variation in the amplitude of T-wave in the electrocardiogram(ECG)signal in an ABAB-pattern.TWA has been proven to be a very important indicator of malignant arrhythmia risk stratification.A new method to detect TWA by combining fractional Fourier transform(FRFT)and tensor decomposition is proposed.First,the T-wave vector is extracted from the ECG of each heartbeat,and its FRFT amplitudes at multiple orders are arranged to form a T-wave matrix.Then,a third-order tensor is composed of T-wave matrices of several consecutive heart beats.After tensor decomposition,projection matrices are obtained in three dimensions.The complexity of the projection matrix is measured by Shannon entropy to obtain feature vector to detect the presence of TWA.Results show that the sensitivity,specificity,and accuracy of the algorithm on the MIT-BIH database are 91.16%,94.25%,and 92.68%,respectively.This method effectively utilizes the fractional domain information of ECG,and shows the promising potential of the FRFT in ECG signal processing.展开更多
MicroRNAs （miRNAs） are a class of small non-coding regulatory RNAs, and changes in miRNAs are involved in tumor origin and progression. Studies have shown that miR-20a is overexpressed in human ovarian cancer tissue...MicroRNAs （miRNAs） are a class of small non-coding regulatory RNAs, and changes in miRNAs are involved in tumor origin and progression. Studies have shown that miR-20a is overexpressed in human ovarian cancer tissues and that this miRNA enhances long-term cellular proliferation and invasion capabilities. In this study, a positive correlation between serum miR-20a expression and ovarian cancer stage was observed. We found that miR-20a binds directly to the 3＇-untranslated region of MICA/B mRNA, resulting in its degradation and reducing its protein levels on the plasma membrane. Reduction of membrane-bound MICA/B proteins, which are ligands of the natural killer group 2 member D （NKG2D） receptor found on natural killer （NK） cells, y＋ T cells and CD8＋ T cells, allows tumor cells to evade immune-mediated killing. Notably, antagonizing miR-20a action enhanced the NKG2D-mediated killing of tumor cells in both in vitro and in vivo models of tumors. Taken together, our data indicate that increased levels of miR-20a in tumor cells may indirectly suppress NK cell cytotoxicity by downregulating MICA/B expression. These data provide a potential link between metastasis capability and immune escape of tumor cells from NK cells.展开更多
Two-dimensional layered IV-VI chalcogenides are attracting great interest for applications in next-generation optoelectronic, photovoltaic, and thermoelectric devices. However, great challenges in the controllable syn...Two-dimensional layered IV-VI chalcogenides are attracting great interest for applications in next-generation optoelectronic, photovoltaic, and thermoelectric devices. However, great challenges in the controllable synthesis of high-quality IV-VI chalcogenide nanostructures have hindered their in-depth studies and practical applications to date. Here we report, for the first time, a feasible synthesis of single-crystal IV-VI SnSe nanoplates in a controlled manner on mica substrates by vapor transport deposition. The as-grown SnSe nanoplates have approximately square shapes with controllable side lengths varying from I to 6 Dm. Electrical transport and optoelectronic measurements show that as-obtained SnSe nanoplates display p-type conductivity and high photoresponsivity.展开更多
Estrogen is involved in promoting lung cancer cell division and metastasis. MICA and MICB function as ligands for NKG2D, an important immunoreceptor expressed on natural killer （NK） cells. However, whether estrogen ...Estrogen is involved in promoting lung cancer cell division and metastasis. MICA and MICB function as ligands for NKG2D, an important immunoreceptor expressed on natural killer （NK） cells. However, whether estrogen regulates MICA/ B expression and affects tumor immune escape remains unknown. In this study, we measured the mRNA levels of MICA, MICB and ADAM 17in non-small cell lung cancer （NSCLC） cell lines treated with estrogen. Surface expression of MICA/B on LTEP-a2 and A549 was detected using flow cytometry. We demonstrate that both mRNA and secretory protein levels of M ICA/B in lung adenocarcinoma cell lines were upregulated by estradiol. Estradiol enhanced the expression of ADAM 17, which was associated with the secretion of MICA/B. This secretion of MICA/B downregulated the NKG2D receptor on the surface of NK92 cells and impaired the cytotoxic activity of NK cells. Estradiol enhanced the expression of ADAM17, which was associated with the secretion of MICA/B. Furthermore, a significant correlation between the concentration of estradiol and the expression of MICA was found in tumor tissues of NSCLC patients. Therefore, we conclude that estrogen can regulate the expression and secretion of MICA/B through ADAM 17, which helps lung cancer cells escape NKG2D-mediated immune surveillance.展开更多
In the chemical vapor deposition growth of large-area graphene polycrystalline thin films, the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries （GBs）. The str...In the chemical vapor deposition growth of large-area graphene polycrystalline thin films, the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries （GBs）. The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains, which can significantly affect the performance of the graphene films and impede their industrial applications. Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation. Although the bicrystal has been widely investigated for traditional bulk materials, no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals. In this stud34 we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu （100） substrate. Control of the density of the GBs with a miso- rientation angle of 30° was realized via the controllable rapid growth of sub- centimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment. The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications.展开更多
文摘Application of nitrogen (N) fertilizer is one of the most important approaches on improving maize grain yield. However, as is known to all, overuse N fertilizer not only leads to decline of N use efficiency and maize yield, but also leads to potential risk to environment pollution. This experiment was conducted to determine the effects of N fertilizer applications with nine different treatments on soil physical-chemical characters and maize grain yield using hybrid variety Zhengdan 958 in 2011 and 2012. Results indicated that the soil bulk densities of T2 (CK) and T1 were the lowest compared to other treatments in 2011 and 2012, respectively, whereas the soil bulk density of T5 in 2011 and T3 in 2012 were higher than other treatments. The soil porosity and field capacity of T5 in 2011 and T3 in 2012 were lower than other treatments, but those of CK in 2011 and T1 in 2012 were higher than other treatments. The pH values of T3 to T7 were lower than other treatments. These results indicated that the soil bulk densities were increased, whereas the soil porosity, field capacity and values pH were decreased by N application at different stages. N application could increase the N contents of leaf and stem, whereas less or excess N application should not significant improve maize yield. Although the soil organic matter and total N contents of T3 were the highest in both 2011 and 2012, the yield of T4 is the highest in both 2011 and 2012. The application amount, period and times of N fertilizer were important to maize yield.
基金supported by the National Natural Science Found-ation of China(No.61701028).
文摘T-wave alternans(TWA)refers to the periodic beat-to-beat variation in the amplitude of T-wave in the electrocardiogram(ECG)signal in an ABAB-pattern.TWA has been proven to be a very important indicator of malignant arrhythmia risk stratification.A new method to detect TWA by combining fractional Fourier transform(FRFT)and tensor decomposition is proposed.First,the T-wave vector is extracted from the ECG of each heartbeat,and its FRFT amplitudes at multiple orders are arranged to form a T-wave matrix.Then,a third-order tensor is composed of T-wave matrices of several consecutive heart beats.After tensor decomposition,projection matrices are obtained in three dimensions.The complexity of the projection matrix is measured by Shannon entropy to obtain feature vector to detect the presence of TWA.Results show that the sensitivity,specificity,and accuracy of the algorithm on the MIT-BIH database are 91.16%,94.25%,and 92.68%,respectively.This method effectively utilizes the fractional domain information of ECG,and shows the promising potential of the FRFT in ECG signal processing.
文摘MicroRNAs （miRNAs） are a class of small non-coding regulatory RNAs, and changes in miRNAs are involved in tumor origin and progression. Studies have shown that miR-20a is overexpressed in human ovarian cancer tissues and that this miRNA enhances long-term cellular proliferation and invasion capabilities. In this study, a positive correlation between serum miR-20a expression and ovarian cancer stage was observed. We found that miR-20a binds directly to the 3＇-untranslated region of MICA/B mRNA, resulting in its degradation and reducing its protein levels on the plasma membrane. Reduction of membrane-bound MICA/B proteins, which are ligands of the natural killer group 2 member D （NKG2D） receptor found on natural killer （NK） cells, y＋ T cells and CD8＋ T cells, allows tumor cells to evade immune-mediated killing. Notably, antagonizing miR-20a action enhanced the NKG2D-mediated killing of tumor cells in both in vitro and in vivo models of tumors. Taken together, our data indicate that increased levels of miR-20a in tumor cells may indirectly suppress NK cell cytotoxicity by downregulating MICA/B expression. These data provide a potential link between metastasis capability and immune escape of tumor cells from NK cells.
文摘Two-dimensional layered IV-VI chalcogenides are attracting great interest for applications in next-generation optoelectronic, photovoltaic, and thermoelectric devices. However, great challenges in the controllable synthesis of high-quality IV-VI chalcogenide nanostructures have hindered their in-depth studies and practical applications to date. Here we report, for the first time, a feasible synthesis of single-crystal IV-VI SnSe nanoplates in a controlled manner on mica substrates by vapor transport deposition. The as-grown SnSe nanoplates have approximately square shapes with controllable side lengths varying from I to 6 Dm. Electrical transport and optoelectronic measurements show that as-obtained SnSe nanoplates display p-type conductivity and high photoresponsivity.
基金This work was supported by the National Natural Science Foundation of China （81101552 and 81201598）, and the Natural Science Foundation of liangsu Province （BK2011571）.
文摘Estrogen is involved in promoting lung cancer cell division and metastasis. MICA and MICB function as ligands for NKG2D, an important immunoreceptor expressed on natural killer （NK） cells. However, whether estrogen regulates MICA/ B expression and affects tumor immune escape remains unknown. In this study, we measured the mRNA levels of MICA, MICB and ADAM 17in non-small cell lung cancer （NSCLC） cell lines treated with estrogen. Surface expression of MICA/B on LTEP-a2 and A549 was detected using flow cytometry. We demonstrate that both mRNA and secretory protein levels of M ICA/B in lung adenocarcinoma cell lines were upregulated by estradiol. Estradiol enhanced the expression of ADAM 17, which was associated with the secretion of MICA/B. This secretion of MICA/B downregulated the NKG2D receptor on the surface of NK92 cells and impaired the cytotoxic activity of NK cells. Estradiol enhanced the expression of ADAM17, which was associated with the secretion of MICA/B. Furthermore, a significant correlation between the concentration of estradiol and the expression of MICA was found in tumor tissues of NSCLC patients. Therefore, we conclude that estrogen can regulate the expression and secretion of MICA/B through ADAM 17, which helps lung cancer cells escape NKG2D-mediated immune surveillance.
基金Acknowledgements We acknowledge financial support from the National Natural Science Foundation of China （Nos. 21173004, 51520105003, 51432002, 21222303 and 51362029） and the National Basic Research Program of China （Nos. 2014CB932500, 2013CB932603, 2012CB933404, 2011CB933003, and 2011CB921904）, the National Program for Support of Top-Notch Young Professionals, and Beijing Municipal Science ＆ Technology Commission （No. Z161100002116002）.
文摘In the chemical vapor deposition growth of large-area graphene polycrystalline thin films, the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries （GBs）. The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains, which can significantly affect the performance of the graphene films and impede their industrial applications. Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation. Although the bicrystal has been widely investigated for traditional bulk materials, no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals. In this stud34 we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu （100） substrate. Control of the density of the GBs with a miso- rientation angle of 30° was realized via the controllable rapid growth of sub- centimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment. The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications.
