The implementation of the Grain for Green Program is a great breakthrough in the history of China's ecological environment construction,which can control soil erosion effectively,increase land productivity and imp...The implementation of the Grain for Green Program is a great breakthrough in the history of China's ecological environment construction,which can control soil erosion effectively,increase land productivity and improve the ecological environment.To investigate the eco-environmental benefits brought by the Grain for Green Program,the spatiotemporal variations of vegetation cover in the growing season from 2000 to 2010 across the Hekou-Longmen(He-Long) region were analyzed by using remote sensing information,meteorological data and land use data.Moreover,the impacts of climate and human activities on vegetation change were evaluated objectively.Annual vegetation cover in the growing season increased very significantly.Increased vegetation cover occurred in 98.7% of the region,of which the area for vegetation cover improved slightly constituted 79.8% of the whole area.Vegetation moderately improved was mainly distributed in the south of the He-Long region,covering 9.6% of the area,and the area for vegetation basically unchanged concentrated in the middle and upper reaches of the Wuding River.Precipitation was found to be an important natural factor influencing vegetation cover change.The area of vegetation cover showing a significantly positive correlation with precipitation occupied 22.14% of the region.As driven by policies from the Grain for Green Program,forestland increased significantly and land use structure became more intensive.Human activities played a positive and effective role in the protection,restoration and improvement of vegetation in the places where vegetation cover was basically unchanged,even though precipitation declined greatly,and vegetation improved moderately with massive increases of forestland and grassland.展开更多
Cells usually undergo a long journey of evolution during the progression from normal to precancerous cells and finally to full-fledged cancer cells. Multiple genomic aberrations are acquired during this journey that c...Cells usually undergo a long journey of evolution during the progression from normal to precancerous cells and finally to full-fledged cancer cells. Multiple genomic aberrations are acquired during this journey that could either act as drivers to confer significant growth advantages or act as passengers with little effect on the tumor growth. Recent advances in sequencing technology have made it feasible to decipher the evolutionary course of a cancer cell on a genome-wide level by evaluating the relative number of mutated alleles. Novel terms such as chromothripsis and chromoplexy have been introduced to describe the newly identified patterns of cancer genome evolution. These new insights have greatly expanded our understanding of the initiation and progression of cancers,which should aid in improving the efficiency of cancer management and treatment.展开更多
[Objective]This study aimed to clear the advantages,disadvantages and applicability of various analysis methods to assess sediment transport modulus in small watersheds using the multi-year observation data. [Method]F...[Objective]This study aimed to clear the advantages,disadvantages and applicability of various analysis methods to assess sediment transport modulus in small watersheds using the multi-year observation data. [Method]Four methods,including the statistical eigenvalues,depolarized arithmetic mean,frequency of erosion intensity and box-whisker plots were applied into calculation of sediment transport modulus in four small watersheds,and then the results of the methods were compared to to filter a method with the widest applicability and scientific validity. [Result] The statistical arithmetic mean and median could hardly represent the concentration and general level of multi-year sediment transport modulus. Although the depolarized arithmetic mean had the tendency of reflecting the general level of data,it lost the extreme value and its information for making decision. The frequency of erosion intensity grade reflected the distribution of data in intensity classification. Box-whisker plot could show the concentration,dispersion and the number of abnormal data. [Conclusion] Multiple methods can be combined to comprehensively and objectively characterize the multi-year sand transport modulus due to their advantages and disadvantages. Additionally,box-whisker plot has good objectivity and applicability in displaying the multi-year data of small watershed.展开更多
The layers of Tamarix cones within sedimentary deposits in arid regions have significant chronological and paleoenvironmental implications.Here,we compare the δ^(18)O values of Tamarix cones in the Hongliujing area o...The layers of Tamarix cones within sedimentary deposits in arid regions have significant chronological and paleoenvironmental implications.Here,we compare the δ^(18)O values of Tamarix cones in the Hongliujing area of Lop Nur with meteorological data for the Ruoqiang meteorological station for 1960-2019 AD.Linear regression analysis was used to reconstruct the average temperature for April and the precipitation for November in the Hongliujing area over the past 200 years.The results showed that the δ^(18)O values were significantly negatively correlated with the temperature for February,April,May,August,December,and with the annual mean temperature;significantly negatively correlated with the precipitation for February and April;significantly negatively correlated with the sunshine hours for March and May;significantly positively correlated with the sunshine hours for February,July,August,October,and December,and with the annual mean values;and significantly correlated with the relative humidity for April,July,August,September,October,and November,and with the annual mean values.Based on the δ^(18)O record of the past 200 years,the Hongliujing area experienced two warm-wet periods(1874-1932 and 2004-2019 AD)and two cold-dry periods(1832–1873 and 1933-2003 AD).Thus,the climate was characterized by alternating warm-wet and cold-dry conditions.Wavelet analysis revealed three main cycles:45 years,29 years,and 14 years.展开更多
Background:Breast cancer stem cells(BCSCs)are considered responsible for cancer relapse and drug resistance.Understanding the identity of BCSCs may open new avenues in breast cancer therapy.Although several discoverie...Background:Breast cancer stem cells(BCSCs)are considered responsible for cancer relapse and drug resistance.Understanding the identity of BCSCs may open new avenues in breast cancer therapy.Although several discoveries have been made on BCSC characterization,the factors critical to the origination of BCSCs are largely unclear.This study aimed to determine whether genomic mutations contribute to the acquisition of cancer stem-like phenotype and to investigate the genetic and transcriptional features of BCSCs.Methods:We detected potential BCSC phenotype-associated mutation hotspot regions by using whole-genome sequencing on parental cancer cells and derived serial-generation spheres in increasing order of BCSC frequency,and then performed target deep DNA sequencing at bulk-cell and single-cell levels.To identify the transcriptional program associated with BCSCs,bulk-cell and single-cell RNA sequencing was performed.Results:By using whole-genome sequencing of bulk cells,potential BCSC phenotype-associated mutation hotspot regions were detected.Validation by target deep DNA sequencing,at both bulk-cell and single-cell levels,revealed no genetic changes specifically associated with BCSC phenotype.Moreover,single-cell RNA sequencing showed profound transcriptomic variability in cancer cells at the single-cell level that predicted BCSC features.Notably,this transcriptomic variability was enriched during the transcription of 74 genes,revealed as BCSC markers.Breast cancer patients with a high risk of relapse exhibited higher expression levels of these BCSC markers than those with a low risk of relapse,thereby highlighting the clinical significance of predicting breast cancer prognosis with these BCSC markers.Conclusions:Transcriptomic variability,not genetic mutations,distinguishes BCSCs from non-BCSCs.The identified 74 BCSC markers have the potential of becoming novel targets for breast cancer therapy.展开更多
Interleukin(IL)-4 is a crucial cytokine in tumor immunology.In the initial murine experiments,IL-4 exhibited potent anti-tumor ability.Tumors genetically modified to produce IL-4 were rejected,while parental tumors gr...Interleukin(IL)-4 is a crucial cytokine in tumor immunology.In the initial murine experiments,IL-4 exhibited potent anti-tumor ability.Tumors genetically modified to produce IL-4 were rejected,while parental tumors grew progressively.Mice rejected IL-4-producing tumors got long-lasting anti-tumor immunity.The comparative study showed that IL-4 induced the most effective immune response among several cytokines in both prophylactic and therapeutic models.All of these indicate IL-4 has strong potential as a tumor therapy agent.However,contrary evidence indeed exists,and is becoming more and more abundant which shows IL-4 is a tumor-promoting molecule.IL-4 amounts are usually elevated in human cancer patients.IL-4 knockout mice are more resistant to tumor challenge than IL-4 competent mice.Furthermore,tumor cells of various histological origins often express increased levels of IL-4 receptor in comparison to their normal counterparts.By carefully examining presently available data,we found the effects of IL-4 in tumor immunity are closely related to its sources,expressing time and dose,as well as the molecular and cellular environments.In this mini-review,we concentrate on illustrating the paradoxical roles and underlying mechanisms of IL-4 in tumor immunity and try to understand how one molecule has opposite effects.展开更多
Soil erosion is a major environmental problem in China.Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information.The aim of this article is to present the methods and r...Soil erosion is a major environmental problem in China.Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information.The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011.A multi-stage,unequal probability,systematic area sampling method was employed.A total of 32,948 sample units,which were either 0.2-3 km2 small catchments or 1 km2 grids,were investigated on site.Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit,along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units.Maps were created by using a spatial interpolation method at national,river basin,and provincial scales.Results showed that the calculated average soil erosion rate was 5 t ha-1 yr-1 in China,and was 18.2 t ha-1 yr-1 for sloped,cultivated cropland.Intensive soil erosion occurred on cropland,overgrazing grassland,and sparsely forested land.The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids.The national average ratio was 13.5%,which represents the area of land in China that requires the implementation of soil conservation practices.These survey results and the maps provide the basic information for national conservation planning and policymaking.展开更多
基金funded by the funding from the Chinese Academy of Sciences(KZCX2-XB3-13,KZZD-EW-04-03)the National Science Foundation of China(41230852,41101265)and China Census for Water
文摘The implementation of the Grain for Green Program is a great breakthrough in the history of China's ecological environment construction,which can control soil erosion effectively,increase land productivity and improve the ecological environment.To investigate the eco-environmental benefits brought by the Grain for Green Program,the spatiotemporal variations of vegetation cover in the growing season from 2000 to 2010 across the Hekou-Longmen(He-Long) region were analyzed by using remote sensing information,meteorological data and land use data.Moreover,the impacts of climate and human activities on vegetation change were evaluated objectively.Annual vegetation cover in the growing season increased very significantly.Increased vegetation cover occurred in 98.7% of the region,of which the area for vegetation cover improved slightly constituted 79.8% of the whole area.Vegetation moderately improved was mainly distributed in the south of the He-Long region,covering 9.6% of the area,and the area for vegetation basically unchanged concentrated in the middle and upper reaches of the Wuding River.Precipitation was found to be an important natural factor influencing vegetation cover change.The area of vegetation cover showing a significantly positive correlation with precipitation occupied 22.14% of the region.As driven by policies from the Grain for Green Program,forestland increased significantly and land use structure became more intensive.Human activities played a positive and effective role in the protection,restoration and improvement of vegetation in the places where vegetation cover was basically unchanged,even though precipitation declined greatly,and vegetation improved moderately with massive increases of forestland and grassland.
文摘Cells usually undergo a long journey of evolution during the progression from normal to precancerous cells and finally to full-fledged cancer cells. Multiple genomic aberrations are acquired during this journey that could either act as drivers to confer significant growth advantages or act as passengers with little effect on the tumor growth. Recent advances in sequencing technology have made it feasible to decipher the evolutionary course of a cancer cell on a genome-wide level by evaluating the relative number of mutated alleles. Novel terms such as chromothripsis and chromoplexy have been introduced to describe the newly identified patterns of cancer genome evolution. These new insights have greatly expanded our understanding of the initiation and progression of cancers,which should aid in improving the efficiency of cancer management and treatment.
基金Supported by National Key R&D Plan Topics (2016YFC0503705)Major Project of High-resolution Earth Observation System (08 Y30B07 900113/15)Dynamic Monitoring Project of National Water and Soil Loss and Optimization Layout Project of National Water and Soil Conservation Monitoring Point (126216229000200002)。
文摘[Objective]This study aimed to clear the advantages,disadvantages and applicability of various analysis methods to assess sediment transport modulus in small watersheds using the multi-year observation data. [Method]Four methods,including the statistical eigenvalues,depolarized arithmetic mean,frequency of erosion intensity and box-whisker plots were applied into calculation of sediment transport modulus in four small watersheds,and then the results of the methods were compared to to filter a method with the widest applicability and scientific validity. [Result] The statistical arithmetic mean and median could hardly represent the concentration and general level of multi-year sediment transport modulus. Although the depolarized arithmetic mean had the tendency of reflecting the general level of data,it lost the extreme value and its information for making decision. The frequency of erosion intensity grade reflected the distribution of data in intensity classification. Box-whisker plot could show the concentration,dispersion and the number of abnormal data. [Conclusion] Multiple methods can be combined to comprehensively and objectively characterize the multi-year sand transport modulus due to their advantages and disadvantages. Additionally,box-whisker plot has good objectivity and applicability in displaying the multi-year data of small watershed.
基金supported by the National Natural Science Foundation of China(Grant No.41877448)。
文摘The layers of Tamarix cones within sedimentary deposits in arid regions have significant chronological and paleoenvironmental implications.Here,we compare the δ^(18)O values of Tamarix cones in the Hongliujing area of Lop Nur with meteorological data for the Ruoqiang meteorological station for 1960-2019 AD.Linear regression analysis was used to reconstruct the average temperature for April and the precipitation for November in the Hongliujing area over the past 200 years.The results showed that the δ^(18)O values were significantly negatively correlated with the temperature for February,April,May,August,December,and with the annual mean temperature;significantly negatively correlated with the precipitation for February and April;significantly negatively correlated with the sunshine hours for March and May;significantly positively correlated with the sunshine hours for February,July,August,October,and December,and with the annual mean values;and significantly correlated with the relative humidity for April,July,August,September,October,and November,and with the annual mean values.Based on the δ^(18)O record of the past 200 years,the Hongliujing area experienced two warm-wet periods(1874-1932 and 2004-2019 AD)and two cold-dry periods(1832–1873 and 1933-2003 AD).Thus,the climate was characterized by alternating warm-wet and cold-dry conditions.Wavelet analysis revealed three main cycles:45 years,29 years,and 14 years.
基金supported by Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(No.IRT_17R15)National Natural Science Foundation of China(Nos.81630005 to QL,81573025 to QL,81472637 to ZL,81672784 to ZL,and 81602200 to DL)+2 种基金Innovative Research Team in University of Liaoning(No.LT2017001 to QL)The program for climbing Scholars of Liaoning,Dalian High-level Talent Innovation Program(2016RD12 to QL)International Scientific and Technological Cooperation of Dalian(2015F11GH095 to QL).
文摘Background:Breast cancer stem cells(BCSCs)are considered responsible for cancer relapse and drug resistance.Understanding the identity of BCSCs may open new avenues in breast cancer therapy.Although several discoveries have been made on BCSC characterization,the factors critical to the origination of BCSCs are largely unclear.This study aimed to determine whether genomic mutations contribute to the acquisition of cancer stem-like phenotype and to investigate the genetic and transcriptional features of BCSCs.Methods:We detected potential BCSC phenotype-associated mutation hotspot regions by using whole-genome sequencing on parental cancer cells and derived serial-generation spheres in increasing order of BCSC frequency,and then performed target deep DNA sequencing at bulk-cell and single-cell levels.To identify the transcriptional program associated with BCSCs,bulk-cell and single-cell RNA sequencing was performed.Results:By using whole-genome sequencing of bulk cells,potential BCSC phenotype-associated mutation hotspot regions were detected.Validation by target deep DNA sequencing,at both bulk-cell and single-cell levels,revealed no genetic changes specifically associated with BCSC phenotype.Moreover,single-cell RNA sequencing showed profound transcriptomic variability in cancer cells at the single-cell level that predicted BCSC features.Notably,this transcriptomic variability was enriched during the transcription of 74 genes,revealed as BCSC markers.Breast cancer patients with a high risk of relapse exhibited higher expression levels of these BCSC markers than those with a low risk of relapse,thereby highlighting the clinical significance of predicting breast cancer prognosis with these BCSC markers.Conclusions:Transcriptomic variability,not genetic mutations,distinguishes BCSCs from non-BCSCs.The identified 74 BCSC markers have the potential of becoming novel targets for breast cancer therapy.
基金This work was supported by Chinese Academy of Sciences(KSCX2-YW-R-42)National Natural Science Foundation of China(30771972 and 30700287)+1 种基金Ministry of Science and Technology of China(2006CB504304,2006CB910901,and 2009CB918900)Ministry of Education,Culture,Sports,Science and Technology(MEXT)of Japan.
文摘Interleukin(IL)-4 is a crucial cytokine in tumor immunology.In the initial murine experiments,IL-4 exhibited potent anti-tumor ability.Tumors genetically modified to produce IL-4 were rejected,while parental tumors grew progressively.Mice rejected IL-4-producing tumors got long-lasting anti-tumor immunity.The comparative study showed that IL-4 induced the most effective immune response among several cytokines in both prophylactic and therapeutic models.All of these indicate IL-4 has strong potential as a tumor therapy agent.However,contrary evidence indeed exists,and is becoming more and more abundant which shows IL-4 is a tumor-promoting molecule.IL-4 amounts are usually elevated in human cancer patients.IL-4 knockout mice are more resistant to tumor challenge than IL-4 competent mice.Furthermore,tumor cells of various histological origins often express increased levels of IL-4 receptor in comparison to their normal counterparts.By carefully examining presently available data,we found the effects of IL-4 in tumor immunity are closely related to its sources,expressing time and dose,as well as the molecular and cellular environments.In this mini-review,we concentrate on illustrating the paradoxical roles and underlying mechanisms of IL-4 in tumor immunity and try to understand how one molecule has opposite effects.
文摘Soil erosion is a major environmental problem in China.Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information.The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011.A multi-stage,unequal probability,systematic area sampling method was employed.A total of 32,948 sample units,which were either 0.2-3 km2 small catchments or 1 km2 grids,were investigated on site.Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit,along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units.Maps were created by using a spatial interpolation method at national,river basin,and provincial scales.Results showed that the calculated average soil erosion rate was 5 t ha-1 yr-1 in China,and was 18.2 t ha-1 yr-1 for sloped,cultivated cropland.Intensive soil erosion occurred on cropland,overgrazing grassland,and sparsely forested land.The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids.The national average ratio was 13.5%,which represents the area of land in China that requires the implementation of soil conservation practices.These survey results and the maps provide the basic information for national conservation planning and policymaking.
