This research classified vegetation types and evaluated net primary productivity （NPP） of southern China＇s grasslands based on the improved comprehensive and sequential classification system （CSCS）, and proposed ...This research classified vegetation types and evaluated net primary productivity （NPP） of southern China＇s grasslands based on the improved comprehensive and sequential classification system （CSCS）, and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations （9 grasslands and 5 forests） were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest （〈600 g C m＇2yrl）. The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest （48.44 Tg C）, and mixed grassland class was the second （16.54 Tg C）, followed by alpine grassland class （3.22 Tg C）, with tundra grassland class being the lowest （0.25 Tg C）. For all the grasslands types, the total NPP of forest meadow was the highest （34.81 Tg C）, followed by sparse forest brush （16.54 Tg C）, and montane meadow was the lowest （0.01 Tg C）.展开更多
作为高铁牵引供电系统的重要组成部分,接触网系统承担着向动车组传输电能的重要功能.实际工程运营表明,受弓网交互产生的持续冲击以及外部环境的影响,接触网支撑部件可能会出现“松、脱、断、裂”等缺陷,导致接触网结构可靠性下降,严重...作为高铁牵引供电系统的重要组成部分,接触网系统承担着向动车组传输电能的重要功能.实际工程运营表明,受弓网交互产生的持续冲击以及外部环境的影响,接触网支撑部件可能会出现“松、脱、断、裂”等缺陷,导致接触网结构可靠性下降,严重影响接触网系统稳定运行.因此,及时精确定位接触网支撑部件(CSCs),对保障高铁安全运行和完善接触网检修维护策略具有重大意义.然而,CSCs的检测通常面临着零部件种类多、尺度差异大、部分零部件微小的问题.针对以上问题,本文提出一种基于多尺度融合金字塔焦点网络的接触网零部件检测算法,将平衡模块和特征金字塔模块相结合,提高对小目标的检测性能.首先,设计了可分离残差金字塔聚合模块(SRPAM),用于优化模型多尺度特征提取能力、扩大感受野,缓解CSCs检测的多尺度问题;其次,设计了一种基于平衡特征金字塔的路径聚合网络(PA-BFPN),用于提升跨层特征融合效率和小目标检测性能.最后,通过对比试验、可视化实验和消融实验证明了所提方法的有效性和优越性.其中,所提的MFPFCOS在CSCs数据集上的检测精度(mAP)能够在达到48.6%的同时,实现30的FLOPs(Floating point operations per second),表明所提方法能够在检测精度和检测速度之间保持良好的平衡.展开更多
Background:Despite the identification of numerous therapeutic targets in lung cancer,achieving significant efficacy has been challenging.TNFRSF21 plays an important role in various cancers.We investigated the function...Background:Despite the identification of numerous therapeutic targets in lung cancer,achieving significant efficacy has been challenging.TNFRSF21 plays an important role in various cancers.We investigated the function of TNFRSF21 in lung adenocarcinoma(LUAD).Methods:The prognostic value of TNFRSF21 expression in lung cancer was evaluated by the GEPIA and Kaplan-Meier Plotter databases.Lung cancer cell viability was assessed by the CCK8 assay.TNFRSF21 expression patterns in lung cancer tissues and cells were examined using RT-PCR assay.Tumor sphere growth was evaluated through tumor sphere formation assays.MtROS contents in lung cancer cells were observed through MitoSOX fluorescent assays.Result:TNFRSF21 was up-regulated in LUAD patients.TNFRSF21 induction was particularly notable in LUAD,especially in cancerous cells(A549,H1299,H460,and SPC-A1),compared to BEAS-2B cells.Additionally,TNFRSF21 was increased in cisplatin(DDP)-resistant LUAD cells.Loss of TNFRSF21 significantly inhibited LUAD cell growth.It was observed that forced expression of TNFRSF21 contributed to tumor cell proliferation and DDP resistance.The production of ROS was found to participate in the inhibitory effects on lung cancer stem cells(CSCs),with decreased TNFRSF21 restraining ROS contents.Collectively,these findings reveal that the downregulation of TNFRSF21 promotes ROS contents to restrain the lung CSC-like characteristics via modulation of CD44 and CD133.Conclusions:In conclusion,TNFRSF21 may act as a novel target for lung cancer chemotherapy,particularly for eradicating lung CSCs.展开更多
Cancer stem cells(CSCs)are a major challenge in cancer therapy.Stem cell-like cells form a unique subpopulation within many tumors,which govern the degree of malignancy by promoting metastasis,recurrence,heterogeneity...Cancer stem cells(CSCs)are a major challenge in cancer therapy.Stem cell-like cells form a unique subpopulation within many tumors,which govern the degree of malignancy by promoting metastasis,recurrence,heterogeneity,and resistance to drug and radiation.Furthermore,these cells can persist in patients even after undergoing multiple cycles of conventional cancer therapy via dormancy,where they no longer dividing but remain active.These may cause cancer recurrence at any time,even years after a supposed cure,and remain invisible to the immune system.Targeting specific surface markers,signaling pathways and tumor microenvironment,which all have a significant effect on CSC function and maintenance,could help to eradicate CSCs and improve patient survival.Combinations of traditional therapies with nano-based drug delivery systems can efficiently target CSCs.Considering the biology and properties of CSCs,we classify recent approaches involving nanoparticle engineering,extracellular matrix modulation,cocktail strategies,multi-stage therapy,CSC defanging,Trojan horse systems,targeted therapy and organelle targeting.We highlight the most recent advances in nanocarrier design and drug delivery technologies to target CSCs,combined with conventional treatment in preclinical and clinical trials.The prospects of these approaches for CSCs elimination and recurrent cancer treatment are discussed.展开更多
The B lymphoma Mo-MLV insertion region 1 homolog(Bmi-1)protein of the polycomb complex is an essential mediator of the epigenetic transcriptional silencing by the chromatin structure.It has been reported to be crucial...The B lymphoma Mo-MLV insertion region 1 homolog(Bmi-1)protein of the polycomb complex is an essential mediator of the epigenetic transcriptional silencing by the chromatin structure.It has been reported to be crucial for homeostasis of the stem cells and tumorigenesis.Though years of investigation have clarified Bmi-1’s transcriptional regulation,post-translational modifications,and functions in controlling cellular bioenergetics,pathologies,and DNA damage response,the full potential of this protein with so many diverse roles are still unfulfilled.Bmi-1 is overexpressed in many human malignancies.Unraveling the Bmi-1’s precise functional role in head and neck cancers can be attractive for mechanisms-based developmental therapeutics.This review attempts to synthesize the current knowledge on Bmi-1 with an emphasis on the role that Bmi-1 plays in oral cancer progression and evaluates how this can be used in advancing clinical treatment strategies for head and neck cancer.Bmi-1 is a promising target for therapy because it has been linked to a stemness and oncogenesis signature.However,to use Bmi-1 as a prognostic marker and a therapeutic target in the long run,new methods are imperative for further characterization of the physiological roles of Bmi-1.Current biological insights of Bmi-1 as a master regulator of stem cell self-renewal have emerged as a prominent player in cancer stem cell(CSC)biology.Bmi-1+cells mediate chemoresistance and metastasis.On the other hand,inhibiting Bmi-1 rescinds CSC function and re-sensitizes cancer cells to chemotherapy.Therefore,elucidating therapeutic approaches targeting Bmi-1 can be leveraged to further research analysis to advance clinical treatment strategies for head and neck cancer.展开更多
The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor a...The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.展开更多
基金the National Basic Research Program of China(2010CB950702)the National High-Technology Reaearch and Development Program of China(2007AA10Z231)the Asia-Pacific Network for Global Change Research Project(ARCP201106CMY-Li)
文摘This research classified vegetation types and evaluated net primary productivity （NPP） of southern China＇s grasslands based on the improved comprehensive and sequential classification system （CSCS）, and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations （9 grasslands and 5 forests） were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest （〈600 g C m＇2yrl）. The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest （48.44 Tg C）, and mixed grassland class was the second （16.54 Tg C）, followed by alpine grassland class （3.22 Tg C）, with tundra grassland class being the lowest （0.25 Tg C）. For all the grasslands types, the total NPP of forest meadow was the highest （34.81 Tg C）, followed by sparse forest brush （16.54 Tg C）, and montane meadow was the lowest （0.01 Tg C）.
文摘作为高铁牵引供电系统的重要组成部分,接触网系统承担着向动车组传输电能的重要功能.实际工程运营表明,受弓网交互产生的持续冲击以及外部环境的影响,接触网支撑部件可能会出现“松、脱、断、裂”等缺陷,导致接触网结构可靠性下降,严重影响接触网系统稳定运行.因此,及时精确定位接触网支撑部件(CSCs),对保障高铁安全运行和完善接触网检修维护策略具有重大意义.然而,CSCs的检测通常面临着零部件种类多、尺度差异大、部分零部件微小的问题.针对以上问题,本文提出一种基于多尺度融合金字塔焦点网络的接触网零部件检测算法,将平衡模块和特征金字塔模块相结合,提高对小目标的检测性能.首先,设计了可分离残差金字塔聚合模块(SRPAM),用于优化模型多尺度特征提取能力、扩大感受野,缓解CSCs检测的多尺度问题;其次,设计了一种基于平衡特征金字塔的路径聚合网络(PA-BFPN),用于提升跨层特征融合效率和小目标检测性能.最后,通过对比试验、可视化实验和消融实验证明了所提方法的有效性和优越性.其中,所提的MFPFCOS在CSCs数据集上的检测精度(mAP)能够在达到48.6%的同时,实现30的FLOPs(Floating point operations per second),表明所提方法能够在检测精度和检测速度之间保持良好的平衡.
基金supported by the Scientific Research Program of Science and Technology Bureau of Huai’an City(Grant No.HAB202119).
文摘Background:Despite the identification of numerous therapeutic targets in lung cancer,achieving significant efficacy has been challenging.TNFRSF21 plays an important role in various cancers.We investigated the function of TNFRSF21 in lung adenocarcinoma(LUAD).Methods:The prognostic value of TNFRSF21 expression in lung cancer was evaluated by the GEPIA and Kaplan-Meier Plotter databases.Lung cancer cell viability was assessed by the CCK8 assay.TNFRSF21 expression patterns in lung cancer tissues and cells were examined using RT-PCR assay.Tumor sphere growth was evaluated through tumor sphere formation assays.MtROS contents in lung cancer cells were observed through MitoSOX fluorescent assays.Result:TNFRSF21 was up-regulated in LUAD patients.TNFRSF21 induction was particularly notable in LUAD,especially in cancerous cells(A549,H1299,H460,and SPC-A1),compared to BEAS-2B cells.Additionally,TNFRSF21 was increased in cisplatin(DDP)-resistant LUAD cells.Loss of TNFRSF21 significantly inhibited LUAD cell growth.It was observed that forced expression of TNFRSF21 contributed to tumor cell proliferation and DDP resistance.The production of ROS was found to participate in the inhibitory effects on lung cancer stem cells(CSCs),with decreased TNFRSF21 restraining ROS contents.Collectively,these findings reveal that the downregulation of TNFRSF21 promotes ROS contents to restrain the lung CSC-like characteristics via modulation of CD44 and CD133.Conclusions:In conclusion,TNFRSF21 may act as a novel target for lung cancer chemotherapy,particularly for eradicating lung CSCs.
基金supported by Tabriz University of Medical Sciences,grant number 65364.
文摘Cancer stem cells(CSCs)are a major challenge in cancer therapy.Stem cell-like cells form a unique subpopulation within many tumors,which govern the degree of malignancy by promoting metastasis,recurrence,heterogeneity,and resistance to drug and radiation.Furthermore,these cells can persist in patients even after undergoing multiple cycles of conventional cancer therapy via dormancy,where they no longer dividing but remain active.These may cause cancer recurrence at any time,even years after a supposed cure,and remain invisible to the immune system.Targeting specific surface markers,signaling pathways and tumor microenvironment,which all have a significant effect on CSC function and maintenance,could help to eradicate CSCs and improve patient survival.Combinations of traditional therapies with nano-based drug delivery systems can efficiently target CSCs.Considering the biology and properties of CSCs,we classify recent approaches involving nanoparticle engineering,extracellular matrix modulation,cocktail strategies,multi-stage therapy,CSC defanging,Trojan horse systems,targeted therapy and organelle targeting.We highlight the most recent advances in nanocarrier design and drug delivery technologies to target CSCs,combined with conventional treatment in preclinical and clinical trials.The prospects of these approaches for CSCs elimination and recurrent cancer treatment are discussed.
文摘The B lymphoma Mo-MLV insertion region 1 homolog(Bmi-1)protein of the polycomb complex is an essential mediator of the epigenetic transcriptional silencing by the chromatin structure.It has been reported to be crucial for homeostasis of the stem cells and tumorigenesis.Though years of investigation have clarified Bmi-1’s transcriptional regulation,post-translational modifications,and functions in controlling cellular bioenergetics,pathologies,and DNA damage response,the full potential of this protein with so many diverse roles are still unfulfilled.Bmi-1 is overexpressed in many human malignancies.Unraveling the Bmi-1’s precise functional role in head and neck cancers can be attractive for mechanisms-based developmental therapeutics.This review attempts to synthesize the current knowledge on Bmi-1 with an emphasis on the role that Bmi-1 plays in oral cancer progression and evaluates how this can be used in advancing clinical treatment strategies for head and neck cancer.Bmi-1 is a promising target for therapy because it has been linked to a stemness and oncogenesis signature.However,to use Bmi-1 as a prognostic marker and a therapeutic target in the long run,new methods are imperative for further characterization of the physiological roles of Bmi-1.Current biological insights of Bmi-1 as a master regulator of stem cell self-renewal have emerged as a prominent player in cancer stem cell(CSC)biology.Bmi-1+cells mediate chemoresistance and metastasis.On the other hand,inhibiting Bmi-1 rescinds CSC function and re-sensitizes cancer cells to chemotherapy.Therefore,elucidating therapeutic approaches targeting Bmi-1 can be leveraged to further research analysis to advance clinical treatment strategies for head and neck cancer.
基金supported in part by the Jiangsu Natural Science Foundation of China under Grant BK20180013in part by the Shenzhen Science and Technology Innovation Committee(STIC)under Grant JCYJ20180306174439784.
文摘The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.
