Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on lo...Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on local hydrology,climate,biodiversity,and food production[1,2].However,maps,that contain knowledge on the distribution,pattern and composition of various land use types in urban areas,are limited to city level.The mapping standard on data sources,methods,land use classification schemes varies from city to city,due to differences in financial input and skills of mapping personnel.To address various national and global environmental challenges caused by urbanization,it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping methods.This is because,only with urban land use maps produced with similar criteria,consistent environmental policies can be made,and action efforts can be compared and assessed for large scale environmental administration.However,despite of the fact that a number of urban-extent maps exist at global scales[3,4],more detailed urban land use maps do not exist at the same scale.Even at big country or regional levels such as for the United States,China and European Union,consistent land use mapping efforts are rare[5,6](e.g.,https://sdi4apps.eu/open_land_use/).展开更多
Objective:Anlotinib hydrochloride is a multitarget tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor,fibroblast growth factor receptor,platelet-derived growth factor receptor,c-Kit,and...Objective:Anlotinib hydrochloride is a multitarget tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor,fibroblast growth factor receptor,platelet-derived growth factor receptor,c-Kit,and c-MET;therefore,it exhibits both antitumor and anti-angiogenetic activities.A phase III trial has shown that anlotinib improved progression-free survival(PFS)and overall survival(OS)in patients with advanced non-small cell lung cancer(NSCLC),who presented with progressive disease or intolerance after standard chemotherapy.This study aimed to analyze the characteristics of patients receiving anlotinib treatment to determine the dominant populations who are fit for the treatment.Methods:Data were collected from March 2015 to January 2017 from a randomized,double-blind,placebo-controlled,multicenter,phase III trial of anlotinib(ALTER0303).A total of 437 patients were enrolled and randomly allocated(2:1)to the anlotinib and placebo groups.Kaplan–Meier analysis and log-rank test were performed to compare PFS and OS.Cox proportional hazards model was adopted for multivariate prognostic analysis.Results:Multivariate analysis indicated that high post-therapeutic peripheral blood granulocyte/lymphocyte ratio and elevated alkaline phosphatase levels were independent risk factors for PFS.Meanwhile,elevated thyroid-stimulating hormone,blood glucose,and triglyceride levels;hypertension;and hand–foot syndrome were independent protective factors of PFS.High posttherapeutic peripheral blood granulocyte/lymphocyte ratio,an Eastern Cooperative Oncology Group(ECOG)score≥2,and the sum of the maximal target lesion length at baseline were independent risk factors of OS,and hypertriglyceridemia was an independent protective factor of OS.Conclusions:This study preliminarily explored the possible factors that affected PFS and OS after anlotinib treatment in patients with advanced refractory NSCLC,and the baseline characteristics of the therapeutically dominant populations were then identified.展开更多
The growing demands of brain science and artificial intelligence create an urgent need for the development of artificial neural networks(ANNs)that can mimic the structural,functional and biological features of human n...The growing demands of brain science and artificial intelligence create an urgent need for the development of artificial neural networks(ANNs)that can mimic the structural,functional and biological features of human neural networks.Nanophotonics,which is the study of the behaviour of light and the light–matter interaction at the nanometre scale,has unveiled new phenomena and led to new applications beyond the diffraction limit of light.These emerging nanophotonic devices have enabled scientists to develop paradigm shifts of research into ANNs.In the present review,we summarise the recent progress in nanophotonics for emulating the structural,functional and biological features of ANNs,directly or indirectly.展开更多
Matrix computation,as a fundamental building block of information processing in science and technology,contributes most of the computational overheads in modern signal processing and artificial intelligence algorithms...Matrix computation,as a fundamental building block of information processing in science and technology,contributes most of the computational overheads in modern signal processing and artificial intelligence algorithms.Photonic accelerators are designed to accelerate specific categories of computing in the optical domain,especially matrix multiplication,to address the growing demand for computing resources and capacity.Photonic matrix multiplication has much potential to expand the domain of telecommunication,and artificial intelligence benefiting from its superior performance.Recent research in photonic matrix multiplication has flourished and may provide opportunities to develop applications that are unachievable at present by conventional electronic processors.In this review,we first introduce the methods of photonic matrix multiplication,mainly including the plane light conversion method,Mach–Zehnder interferometer method and wavelength division multiplexing method.We also summarize the developmental milestones of photonic matrix multiplication and the related applications.Then,we review their detailed advances in applications to optical signal processing and artificial neural networks in recent years.Finally,we comment on the challenges and perspectives of photonic matrix multiplication and photonic acceleration.展开更多
Sorafenib is the first-line chemotherapeutic therapy for advanced hepatocellular carcinoma(HCC).However,sorafenib resistance significantly limits its therapeutic efficacy,and the mechanisms underlying resistance have ...Sorafenib is the first-line chemotherapeutic therapy for advanced hepatocellular carcinoma(HCC).However,sorafenib resistance significantly limits its therapeutic efficacy,and the mechanisms underlying resistance have not been fully clarified.Here we report that a circular RNA,circRNA-SORE(a circular RNA upregulated in sorafenib-resistant HCC cells),plays a significant role in sorafenib resistance in HCC.We found that circRNA-SORE is upregulated in sorafenib-resistant HCC cells and depletion of circRNA-SORE substantially increases the cell-killing ability of sorafenib.Further studies revealed that circRNA-SORE binds the master oncogenic protein YBX1 in the cytoplasm,which prevents YBX1 nuclear interaction with the E3 ubiquitin ligase PRP19 and thus blocks PRP19-mediated YBX1 degradation.Moreover,our in vitro and in vivo results suggest that circRNA-SORE is transported by exosomes to spread sorafenib resistance among HCC cells.Using different HCC mouse models,we demonstrated that silencing circRNA-SORE by injection of siRNA could substantially overcome sorafenib resistance.Our study provides a proof-of-concept demonstration for a potential strategy to overcome sorafenib resistance in HCC patients by targeting circRNA-SORE or YBX1.展开更多
Integrated study on the tectonic, basin filling and thermal evolution of the Tertiary basins on the northern margin of the South China Sea has indicated that the rift continental margin on the northern South China Sea...Integrated study on the tectonic, basin filling and thermal evolution of the Tertiary basins on the northern margin of the South China Sea has indicated that the rift continental margin on the northern South China Sea is not a passive margin and that the western margin is characteristic of the transformextension. Episodic rifting and the thermal events since 10 Ma in the area have been documented by the integrated analysis of dynamic process. It has been clarified that the tectono-thermal events have exerted a significant influence on basin features and hydrocarbon accumulation, and particularly, the westward collision of the Lusong Island Arc, the generation of densely spaced faults in the Pearl River Mouth Basin, the rapid subsidence, high heat flow and large-scale over pressure and thermal-fluid breakthrough in the Yinggehai and the Qiongdongnan basins have proved to be the important factors determining the formation of oil and gas in these basins.展开更多
The teeth are highly differentiated chewing organs formed by the development of tooth germ tissue located in the jaw and consist of the enamel, dentin, cementum, pulp, and periodontal tissue. Moreover, the teeth have ...The teeth are highly differentiated chewing organs formed by the development of tooth germ tissue located in the jaw and consist of the enamel, dentin, cementum, pulp, and periodontal tissue. Moreover, the teeth have a complicated regulatory mechanism, special histologic origin, diverse structure, and important function in mastication, articulation, and aesthetics. These characteristics, to a certain extent, greatly complicate the research in tooth regeneration. Recently, new ideas for tooth and tissue regeneration have begun to appear with rapid developments in the theories and technologies in tissue engineering. Numerous types of stem cells have been isolated from dental tissue, such as dental pulp stem cells (DPSCs), stem cells isolated from human pulp of exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), stem cells from apical papilla (SCAPs), and dental follicle cells (DFCs). All these cells can regenerate the tissue of tooth. This review outlines the cell types and strategies of stem cell therapy applied in tooth regeneration, in order to provide theoretical basis for clinical treatments.展开更多
Optical machine learning has emerged as an important research area that,by leveraging the advantages inherent to optical signals,such as parallelism and high speed,paves the way for a future where optical hardware can...Optical machine learning has emerged as an important research area that,by leveraging the advantages inherent to optical signals,such as parallelism and high speed,paves the way for a future where optical hardware can process data at the speed of light.In this work,we present such optical devices for data processing in the form of single-layer nanoscale holographic perceptrons trained to perform optical inference tasks.We experimentally show the functionality of these passive optical devices in the example of decryptors trained to perform optical inference of single or whole classes of keys through symmetric and asymmetric decryption.The decryptors,designed for operation in the near-infrared region,are nanoprinted on complementary metal-oxide-semiconductor chips by galvo-dithered two-photon nanolithography with axial nanostepping of 10 nm achieving a neuron density of>500 million neurons per square centimetre.This power-efficient commixture of machine learning and on-chip integration may have a transformative impact on optical decryption3,sensing4,medical diagnostics5 and computing6,7.展开更多
This experiment was conducted to investigate the effects of dietary arginine levels on growth performance, body composition, serum biochemical indices and resistance ability against ammonia-nitrogen stress in juvenile...This experiment was conducted to investigate the effects of dietary arginine levels on growth performance, body composition, serum biochemical indices and resistance ability against ammonia-nitrogen stress in juvenile yellow catfish(Pelteobagrus fulvidraco). Five isonitrogenous and isolipidic diets(42%protein and 9% lipid) were formulated to contain graded levels of arginine(2.44%, 2.64%, 2.81%, 3.01% and3.23% of diet), by supplementing L-Arginine HCI. Seven hundred juvenile yellow catfish with an initial average body weight of 1.13 ± 0.02 g were randomly divided into 5 groups with 4 replicates of 35 fish each and each group was fed one of the diets. After 56 d feeding, fish were exposed to 100 mg/L of ammonia-nitrogen for 72 h. The results showed that weight gain(WG) and specific growth rate(SGR) in2.64% and 2.81% groups were significantly higher than those in 3.23% group(P < 0.05). The feed conversation ratio(FCR) in 2,64%, 2,81% and 3.01% groups was significantly decreased when compared with3,23% group. The protein efficiency ratio(PER) in 2.64% group was significantly higher than that in 2.44%and 3.23% groups(P < 0.05). The condition factor(CF) of fish was significantly higher in 2.81% group than that in 2,44% group(P < 0.05). Dietary arginine levels had no significant effect on hepatosomatic index(HSI), viscerosomatic index(VSI), and whole-body dry matter, crude protein, crude lipid, ash contents, as well as serum total protein(TP), triglyceride(TG), glucose(GLU), urea nitrogen(UN) contents and aspartate aminotransferase(AST), alanine aminotransferase(ALT) activities(P> 0.05). After the fish were challenged to ammonia-nitrogen for 72 h, their cumulative mortality rate in 2.81% group was significantly lower than that in 2.44% group(P < 0.05). The results suggested that dietary arginine level at 2.81%could optimize anti-ammonia-nitrogen stress ability of juvenile yellow catfish and a level of 3.23%arginine seemed to depress the growth performance of fish and decreased their tolerance to the ammonia-nitrogen s展开更多
Single-cell RNA sequencing(scRNA-seq)is generally used for profiling transcriptome of individual cells.The droplet-based 10X Genomics Chromium(10X)approach and the plate-based Smart-seq2 full-length method are two fre...Single-cell RNA sequencing(scRNA-seq)is generally used for profiling transcriptome of individual cells.The droplet-based 10X Genomics Chromium(10X)approach and the plate-based Smart-seq2 full-length method are two frequently used scRNA-seq platforms,yet there are only a few thorough and systematic comparisons of their advantages and limitations.Here,by directly comparing the scRNA-seq data generated by these two platforms from the same samples of CD45cells,we systematically evaluated their features using a wide spectrum of analyses.Smart-seq2 detected more genes in a cell,especially low abundance transcripts as well as alternatively spliced transcripts,but captured higher proportion of mitochondrial genes.The composite of Smart-seq2 data also resembled bulk RNA-seq data more.For 10X-based data,we observed higher noise for mRNAs with low expression levels.Approximately 10%30%of all detected transcripts by both platforms were from non-coding genes,with long non-coding RNAs(lncRNAs)accounting for a higher proportion in 10X.10X-based data displayed more severe dropout problem,especially for genes with lower expression levels.However,10X-data can detect rare cell types given its ability to cover a large number of cells.In addition,each platform detected distinct groups of differentially expressed genes between cell clusters,indicating the different characteristics of these technologies.Our study promotes better understanding of these two platforms and offers the basis for an informed choice of these widely used technologies.展开更多
The Five-hundred-meter Aperture Spherical radio Telescope(FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the c...The Five-hundred-meter Aperture Spherical radio Telescope(FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the commissioning progress of the FAST over the past two years. To improve its operational reliability and ensure effective observation time, FAST has been equipped with a real-time information system for the active reflector system and hierarchical commissioning scheme for the feed support system, which ultimately achieves safe operation of the two systems. For meeting the high-performance indices, a highprecision measurement system was set up based on the effective control methods that were implemented for the active reflector system and feed support system. Since the commissioning of the FAST, a low-frequency ultra-wideband receiver and 19-beam1.05-1.45 GHz receiver have been mainly used. Telescope efficiency, pointing accuracy, and system noise temperature were completely tested and ultimately achieved the acceptance indices of the telescope. The FAST has been in the process of national acceptance preparations and has begun to search for pulsars. In the future, it will still strive to improve its capabilities and expand its application prospects.展开更多
The tremendous development of Synthetic Aperture Radar(SAR)missions in recent years facilitates the study of smaller amplitude ground deformation over greater spatial scales using longer time series.However,this poses...The tremendous development of Synthetic Aperture Radar(SAR)missions in recent years facilitates the study of smaller amplitude ground deformation over greater spatial scales using longer time series.However,this poses greater challenges for correcting atmospheric effects due to the wider coverage of SAR imagery than ever.Previous attempts have used observations from Global Positioning System(GPS)and Numerical Weather Models(NWMs)to separate atmospheric delays,but they are limited by(1)The availability(and distribution)of GPS stations;(2)The low spatial resolution of NWM;And(3)The difficulties in quantifying their performance.To overcome these limitations,we have developed the Generic Atmospheric Correction Online Service for InSAR(GACOS)which utilizes the high-resolution European Centre for Medium-Range Weather Forecasts(ECMWF)products using an Iterative Tropospheric Decomposition(ITD)model.This enables the reduction of the coupling effects of the troposphere turbulence and stratification and hence achieves equivalent performances over flat and mountainous terrains.GACOS comprises a range of notable features:(1)Global coverage;(2)All-weather,all-time usability;(3)Available with a maximum of two-day latency;And(4)Indicators available to assess the model’s performance and feasibility.In this paper,we demonstrate some successful applications of the GACOS online service to a variety of geophysical studies.展开更多
In order to improve the autonomous ability of unmanned aerial vehicles(UAV)to implement air combat mission,many artificial intelligence-based autonomous air combat maneuver decision-making studies have been carried ou...In order to improve the autonomous ability of unmanned aerial vehicles(UAV)to implement air combat mission,many artificial intelligence-based autonomous air combat maneuver decision-making studies have been carried out,but these studies are often aimed at individual decision-making in 1 v1 scenarios which rarely happen in actual air combat.Based on the research of the 1 v1 autonomous air combat maneuver decision,this paper builds a multi-UAV cooperative air combat maneuver decision model based on multi-agent reinforcement learning.Firstly,a bidirectional recurrent neural network(BRNN)is used to achieve communication between UAV individuals,and the multi-UAV cooperative air combat maneuver decision model under the actor-critic architecture is established.Secondly,through combining with target allocation and air combat situation assessment,the tactical goal of the formation is merged with the reinforcement learning goal of every UAV,and a cooperative tactical maneuver policy is generated.The simulation results prove that the multi-UAV cooperative air combat maneuver decision model established in this paper can obtain the cooperative maneuver policy through reinforcement learning,the cooperative maneuver policy can guide UAVs to obtain the overall situational advantage and defeat the opponents under tactical cooperation.展开更多
The structure and properties of Cu-Cr-Zr alloy were studied after rapidly solidified aging and solid solution aging.At the early stage of aging （500℃ for 15 rain）, the hardness and the conductivity of the alloy rap...The structure and properties of Cu-Cr-Zr alloy were studied after rapidly solidified aging and solid solution aging.At the early stage of aging （500℃ for 15 rain）, the hardness and the conductivity of the alloy rapidly solidified are 143 HV and 72% IACS, respectively. Under the same aging condition, the hardness and electrical conductivity of the alloy solid solution treated can reach 86 HV and 47% IACS, respectively. The microstructure was analyzed, and the grain size after rapid solidification is much smaller than that after solid solution treatment. By rapidly solidified aging the fine precipitates distribute inside the grains and along the grain boundary, while by solid solution aging there are large Cr particles along the grain boundary.展开更多
Located in the middle of the Tarim Basin, Tazhong is a typical area of compound reservoirs rich in oil and gas found in the Carboniferous, Silurian and Ordovician strata. The proved, probable and possible reserves （3...Located in the middle of the Tarim Basin, Tazhong is a typical area of compound reservoirs rich in oil and gas found in the Carboniferous, Silurian and Ordovician strata. The proved, probable and possible reserves （3P reserves） in the area amount to 5×108 tons, so it is of great significance to study the advances and problems in hydrocarbon exploration in the Tazhong area. On the basis of exploration history and analysis of scientific problems, we outline eight achievements： distribution characteristics of reservoirs, stages of reservoir formation, different sources of oil and gas and their respective contributions, the effective regional caprock and reservoir-caprock combinations dominating the vertical distribution of hydrocarbon reservoirs, the control of the Tazhong Palaeo-uplift on reservoir formation and establishing geologic models, structure balance belts influencing the reconstruction and residual potential of reservoirs after accumulation, the rules and mechanisms of fractures controlling oil and gas, and the types of favorable reservoirs and their characteristics of controlling oil and gas distribution. We further point out the main problems about the oil and gas exploration in the Tazhong area and put forward some relevant proposals.展开更多
The efficacy of chemotherapeutic drug in cancer treatment is often hampered by drug resistance of tumor cells,which is usually caused by abnormal gene expression.RNA interference mediated by si RNA and mi RNA can sele...The efficacy of chemotherapeutic drug in cancer treatment is often hampered by drug resistance of tumor cells,which is usually caused by abnormal gene expression.RNA interference mediated by si RNA and mi RNA can selectively knock down the carcinogenic genes by targeting specific m RNAs.Therefore,combining chemotherapeutic drugs with gene agents could be a promising strategy for cancer therapy.Due to poor stability and solubility associated with gene agents and drugs,suitable protective carriers are needed and have been widely researched for the co-delivery.In this review,we summarize the most commonly used nanocarriers for co-delivery of chemotherapeutic drugs and gene agents,as well as the advances in co-delivery systems.展开更多
Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has spread rapidly throughout the world.SARS-CoV-2 is an enveloped,plus-stranded RNA virus with a single-stranded RNA genome of approximately 30,000 nucleotid...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has spread rapidly throughout the world.SARS-CoV-2 is an enveloped,plus-stranded RNA virus with a single-stranded RNA genome of approximately 30,000 nucleotides.The SARS-CoV-2 genome encodes 29 proteins,including 16 nonstructural,4 structural and 9 accessory proteins.To date,over 1,228 experimental structures of SARS-CoV-2 proteins have been deposited in the Protein Data Bank(PDB),including 16 protein structures,two functional domain structures of nucleocapsid(N)protein,and scores of complexes.Overall,they exhibit high similarity to SARS-CoV proteins.Here,we summarize the progress of structural and functional research on SARS-CoV-2 proteins.These studies provide structural and functional insights into proteins of SARS-CoV-2,and further elucidate the daedal relationship between different components at the atomic level in the viral life cycle,including attachment to the host cell,viral genome replication and transcription,genome packaging and assembly,and virus release.It is important to understand the structural and functional properties of SARS-CoV-2 proteins as it will facilitate the development of anti-CoV drugs and vaccines to prevent and control the current SARS-CoV-2 pandemic.展开更多
基金partially supported by the National Key Research and Development Program of China(2016YFA0600104)supported by donations made by Delos Living LLC,and the Cyrus Tang Foundation+2 种基金supported by the National Natural Science Foundation of China(41471419)Beijing Institute of Urban Planningsupported by the Fundamental Research Funds for the Central Universities(CCNU19TD002).
文摘Land use reflects human activities on land.Urban land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and urbanization.Urban areas have widespread effects on local hydrology,climate,biodiversity,and food production[1,2].However,maps,that contain knowledge on the distribution,pattern and composition of various land use types in urban areas,are limited to city level.The mapping standard on data sources,methods,land use classification schemes varies from city to city,due to differences in financial input and skills of mapping personnel.To address various national and global environmental challenges caused by urbanization,it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping methods.This is because,only with urban land use maps produced with similar criteria,consistent environmental policies can be made,and action efforts can be compared and assessed for large scale environmental administration.However,despite of the fact that a number of urban-extent maps exist at global scales[3,4],more detailed urban land use maps do not exist at the same scale.Even at big country or regional levels such as for the United States,China and European Union,consistent land use mapping efforts are rare[5,6](e.g.,https://sdi4apps.eu/open_land_use/).
文摘Objective:Anlotinib hydrochloride is a multitarget tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor,fibroblast growth factor receptor,platelet-derived growth factor receptor,c-Kit,and c-MET;therefore,it exhibits both antitumor and anti-angiogenetic activities.A phase III trial has shown that anlotinib improved progression-free survival(PFS)and overall survival(OS)in patients with advanced non-small cell lung cancer(NSCLC),who presented with progressive disease or intolerance after standard chemotherapy.This study aimed to analyze the characteristics of patients receiving anlotinib treatment to determine the dominant populations who are fit for the treatment.Methods:Data were collected from March 2015 to January 2017 from a randomized,double-blind,placebo-controlled,multicenter,phase III trial of anlotinib(ALTER0303).A total of 437 patients were enrolled and randomly allocated(2:1)to the anlotinib and placebo groups.Kaplan–Meier analysis and log-rank test were performed to compare PFS and OS.Cox proportional hazards model was adopted for multivariate prognostic analysis.Results:Multivariate analysis indicated that high post-therapeutic peripheral blood granulocyte/lymphocyte ratio and elevated alkaline phosphatase levels were independent risk factors for PFS.Meanwhile,elevated thyroid-stimulating hormone,blood glucose,and triglyceride levels;hypertension;and hand–foot syndrome were independent protective factors of PFS.High posttherapeutic peripheral blood granulocyte/lymphocyte ratio,an Eastern Cooperative Oncology Group(ECOG)score≥2,and the sum of the maximal target lesion length at baseline were independent risk factors of OS,and hypertriglyceridemia was an independent protective factor of OS.Conclusions:This study preliminarily explored the possible factors that affected PFS and OS after anlotinib treatment in patients with advanced refractory NSCLC,and the baseline characteristics of the therapeutically dominant populations were then identified.
基金the support from Australian Research Council(ARC)(Discovery Project 170101775).
文摘The growing demands of brain science and artificial intelligence create an urgent need for the development of artificial neural networks(ANNs)that can mimic the structural,functional and biological features of human neural networks.Nanophotonics,which is the study of the behaviour of light and the light–matter interaction at the nanometre scale,has unveiled new phenomena and led to new applications beyond the diffraction limit of light.These emerging nanophotonic devices have enabled scientists to develop paradigm shifts of research into ANNs.In the present review,we summarise the recent progress in nanophotonics for emulating the structural,functional and biological features of ANNs,directly or indirectly.
基金Chaoran Huang would like to thank Alexander Tait,Bhavin Shastri and Paul Prucnal for the fruitful discussions.J.J.D.acknowledges the support of the National Key Research and Development Project of China(2018YFB2201901)the National Natural Science Foundation of China(61805090,62075075).
文摘Matrix computation,as a fundamental building block of information processing in science and technology,contributes most of the computational overheads in modern signal processing and artificial intelligence algorithms.Photonic accelerators are designed to accelerate specific categories of computing in the optical domain,especially matrix multiplication,to address the growing demand for computing resources and capacity.Photonic matrix multiplication has much potential to expand the domain of telecommunication,and artificial intelligence benefiting from its superior performance.Recent research in photonic matrix multiplication has flourished and may provide opportunities to develop applications that are unachievable at present by conventional electronic processors.In this review,we first introduce the methods of photonic matrix multiplication,mainly including the plane light conversion method,Mach–Zehnder interferometer method and wavelength division multiplexing method.We also summarize the developmental milestones of photonic matrix multiplication and the related applications.Then,we review their detailed advances in applications to optical signal processing and artificial neural networks in recent years.Finally,we comment on the challenges and perspectives of photonic matrix multiplication and photonic acceleration.
基金supported by the National Natural Science Foundation of China under Grant No.81772546(to X.C.),No.81827804(to X.C.)and No.81902367(to J.X.)Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ19H160026(to J.X.)and LGF18H160011(to Y.L.)+6 种基金China Postdoctoral Science Foundation under Grant No.2020M671755(to J.X.)Key Research and Development Project of Zhejiang Province under Grant No.2018C03083(to X.C.)Zhejiang Clinical Research Center of Minimally Invasive Diagnosis and Treatment of Abdominal Diseases under Grant No.2018E50003(to X.C.)Special fund for basic scientific research operating expenses of Zhejiang University under Grant No.2019XZZX005-4-05(to Y.L.)Hepatobiliary and Pancreatic Cancer Research of Hubei Chen Xiaoping Science and Technology Development Foundation under Grant No.CXPJJH11900001-2019308(to J.X.)CXPJJH11900001-2019209(to X.L.)CXPJJH11900009-03(to X.L.).
文摘Sorafenib is the first-line chemotherapeutic therapy for advanced hepatocellular carcinoma(HCC).However,sorafenib resistance significantly limits its therapeutic efficacy,and the mechanisms underlying resistance have not been fully clarified.Here we report that a circular RNA,circRNA-SORE(a circular RNA upregulated in sorafenib-resistant HCC cells),plays a significant role in sorafenib resistance in HCC.We found that circRNA-SORE is upregulated in sorafenib-resistant HCC cells and depletion of circRNA-SORE substantially increases the cell-killing ability of sorafenib.Further studies revealed that circRNA-SORE binds the master oncogenic protein YBX1 in the cytoplasm,which prevents YBX1 nuclear interaction with the E3 ubiquitin ligase PRP19 and thus blocks PRP19-mediated YBX1 degradation.Moreover,our in vitro and in vivo results suggest that circRNA-SORE is transported by exosomes to spread sorafenib resistance among HCC cells.Using different HCC mouse models,we demonstrated that silencing circRNA-SORE by injection of siRNA could substantially overcome sorafenib resistance.Our study provides a proof-of-concept demonstration for a potential strategy to overcome sorafenib resistance in HCC patients by targeting circRNA-SORE or YBX1.
文摘Integrated study on the tectonic, basin filling and thermal evolution of the Tertiary basins on the northern margin of the South China Sea has indicated that the rift continental margin on the northern South China Sea is not a passive margin and that the western margin is characteristic of the transformextension. Episodic rifting and the thermal events since 10 Ma in the area have been documented by the integrated analysis of dynamic process. It has been clarified that the tectono-thermal events have exerted a significant influence on basin features and hydrocarbon accumulation, and particularly, the westward collision of the Lusong Island Arc, the generation of densely spaced faults in the Pearl River Mouth Basin, the rapid subsidence, high heat flow and large-scale over pressure and thermal-fluid breakthrough in the Yinggehai and the Qiongdongnan basins have proved to be the important factors determining the formation of oil and gas in these basins.
基金the grants from the National Natural Science Foundation of China (Nos.31501121,31401255,81570976,and 31500786)Natural Science Foundation research project of Shaanxi Province (Nos.2016JQ8019 and 016KW-005).
文摘The teeth are highly differentiated chewing organs formed by the development of tooth germ tissue located in the jaw and consist of the enamel, dentin, cementum, pulp, and periodontal tissue. Moreover, the teeth have a complicated regulatory mechanism, special histologic origin, diverse structure, and important function in mastication, articulation, and aesthetics. These characteristics, to a certain extent, greatly complicate the research in tooth regeneration. Recently, new ideas for tooth and tissue regeneration have begun to appear with rapid developments in the theories and technologies in tissue engineering. Numerous types of stem cells have been isolated from dental tissue, such as dental pulp stem cells (DPSCs), stem cells isolated from human pulp of exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), stem cells from apical papilla (SCAPs), and dental follicle cells (DFCs). All these cells can regenerate the tissue of tooth. This review outlines the cell types and strategies of stem cell therapy applied in tooth regeneration, in order to provide theoretical basis for clinical treatments.
基金The authors thank Shiwei Zhang and Prof.Xiaodong Li for their enlightening discussions.The authors acknowledge the use of facilities within the RMIT Microscopy and Microanalysis Facility(RMMF)the support of the Shanghai Institute of Intelligent Science and Technology,Tongji University,Shanghai,China.M.G.acknowledges the funding support from the Zhangjiang National Innovation Demonstration Zone(ZJ2019-ZD-005).
文摘Optical machine learning has emerged as an important research area that,by leveraging the advantages inherent to optical signals,such as parallelism and high speed,paves the way for a future where optical hardware can process data at the speed of light.In this work,we present such optical devices for data processing in the form of single-layer nanoscale holographic perceptrons trained to perform optical inference tasks.We experimentally show the functionality of these passive optical devices in the example of decryptors trained to perform optical inference of single or whole classes of keys through symmetric and asymmetric decryption.The decryptors,designed for operation in the near-infrared region,are nanoprinted on complementary metal-oxide-semiconductor chips by galvo-dithered two-photon nanolithography with axial nanostepping of 10 nm achieving a neuron density of>500 million neurons per square centimetre.This power-efficient commixture of machine learning and on-chip integration may have a transformative impact on optical decryption3,sensing4,medical diagnostics5 and computing6,7.
基金supported by the National Natural Science Foundation of China (31402307)the construction of public service platform for the evaluation of the value of aquatic feed and feed additives in Guangdong Province(2015A040404033)
文摘This experiment was conducted to investigate the effects of dietary arginine levels on growth performance, body composition, serum biochemical indices and resistance ability against ammonia-nitrogen stress in juvenile yellow catfish(Pelteobagrus fulvidraco). Five isonitrogenous and isolipidic diets(42%protein and 9% lipid) were formulated to contain graded levels of arginine(2.44%, 2.64%, 2.81%, 3.01% and3.23% of diet), by supplementing L-Arginine HCI. Seven hundred juvenile yellow catfish with an initial average body weight of 1.13 ± 0.02 g were randomly divided into 5 groups with 4 replicates of 35 fish each and each group was fed one of the diets. After 56 d feeding, fish were exposed to 100 mg/L of ammonia-nitrogen for 72 h. The results showed that weight gain(WG) and specific growth rate(SGR) in2.64% and 2.81% groups were significantly higher than those in 3.23% group(P < 0.05). The feed conversation ratio(FCR) in 2,64%, 2,81% and 3.01% groups was significantly decreased when compared with3,23% group. The protein efficiency ratio(PER) in 2.64% group was significantly higher than that in 2.44%and 3.23% groups(P < 0.05). The condition factor(CF) of fish was significantly higher in 2.81% group than that in 2,44% group(P < 0.05). Dietary arginine levels had no significant effect on hepatosomatic index(HSI), viscerosomatic index(VSI), and whole-body dry matter, crude protein, crude lipid, ash contents, as well as serum total protein(TP), triglyceride(TG), glucose(GLU), urea nitrogen(UN) contents and aspartate aminotransferase(AST), alanine aminotransferase(ALT) activities(P> 0.05). After the fish were challenged to ammonia-nitrogen for 72 h, their cumulative mortality rate in 2.81% group was significantly lower than that in 2.44% group(P < 0.05). The results suggested that dietary arginine level at 2.81%could optimize anti-ammonia-nitrogen stress ability of juvenile yellow catfish and a level of 3.23%arginine seemed to depress the growth performance of fish and decreased their tolerance to the ammonia-nitrogen s
基金the National Natural Science Foundation of China(Grant Nos.31530036,81573022,and 31601063).
文摘Single-cell RNA sequencing(scRNA-seq)is generally used for profiling transcriptome of individual cells.The droplet-based 10X Genomics Chromium(10X)approach and the plate-based Smart-seq2 full-length method are two frequently used scRNA-seq platforms,yet there are only a few thorough and systematic comparisons of their advantages and limitations.Here,by directly comparing the scRNA-seq data generated by these two platforms from the same samples of CD45cells,we systematically evaluated their features using a wide spectrum of analyses.Smart-seq2 detected more genes in a cell,especially low abundance transcripts as well as alternatively spliced transcripts,but captured higher proportion of mitochondrial genes.The composite of Smart-seq2 data also resembled bulk RNA-seq data more.For 10X-based data,we observed higher noise for mRNAs with low expression levels.Approximately 10%30%of all detected transcripts by both platforms were from non-coding genes,with long non-coding RNAs(lncRNAs)accounting for a higher proportion in 10X.10X-based data displayed more severe dropout problem,especially for genes with lower expression levels.However,10X-data can detect rare cell types given its ability to cover a large number of cells.In addition,each platform detected distinct groups of differentially expressed genes between cell clusters,indicating the different characteristics of these technologies.Our study promotes better understanding of these two platforms and offers the basis for an informed choice of these widely used technologies.
基金supported by the National Natural Science Foundation of China(Grant Nos.11673039,11573044,11673002,11803051,11503048,and 11203048)the Youth Innovation Promotion Association CAS+4 种基金the Open Project Program of the Key Laboratory of FAST,NAOC,Chinese Academy of Sciencesthe Young Researcher Grant of National Astronomical Observatories,Chinese Academy of Sciencessupported by the Special Funding for Advanced Users,budgeted and administrated by Center for Astronomical Mega-Science,Chinese Academy of Sciences(CAMS)the National Key Research and Development Program of China(Grant No.2017YFA0402600)the CAS "Light of West China" Program
文摘The Five-hundred-meter Aperture Spherical radio Telescope(FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the commissioning progress of the FAST over the past two years. To improve its operational reliability and ensure effective observation time, FAST has been equipped with a real-time information system for the active reflector system and hierarchical commissioning scheme for the feed support system, which ultimately achieves safe operation of the two systems. For meeting the high-performance indices, a highprecision measurement system was set up based on the effective control methods that were implemented for the active reflector system and feed support system. Since the commissioning of the FAST, a low-frequency ultra-wideband receiver and 19-beam1.05-1.45 GHz receiver have been mainly used. Telescope efficiency, pointing accuracy, and system noise temperature were completely tested and ultimately achieved the acceptance indices of the telescope. The FAST has been in the process of national acceptance preparations and has begun to search for pulsars. In the future, it will still strive to improve its capabilities and expand its application prospects.
基金National Natural Science Foundation of China(No.41941019)Fundamental Research Funds for the Central Universities(Nos.300102260301/087,300102260404/087)。
文摘The tremendous development of Synthetic Aperture Radar(SAR)missions in recent years facilitates the study of smaller amplitude ground deformation over greater spatial scales using longer time series.However,this poses greater challenges for correcting atmospheric effects due to the wider coverage of SAR imagery than ever.Previous attempts have used observations from Global Positioning System(GPS)and Numerical Weather Models(NWMs)to separate atmospheric delays,but they are limited by(1)The availability(and distribution)of GPS stations;(2)The low spatial resolution of NWM;And(3)The difficulties in quantifying their performance.To overcome these limitations,we have developed the Generic Atmospheric Correction Online Service for InSAR(GACOS)which utilizes the high-resolution European Centre for Medium-Range Weather Forecasts(ECMWF)products using an Iterative Tropospheric Decomposition(ITD)model.This enables the reduction of the coupling effects of the troposphere turbulence and stratification and hence achieves equivalent performances over flat and mountainous terrains.GACOS comprises a range of notable features:(1)Global coverage;(2)All-weather,all-time usability;(3)Available with a maximum of two-day latency;And(4)Indicators available to assess the model’s performance and feasibility.In this paper,we demonstrate some successful applications of the GACOS online service to a variety of geophysical studies.
基金supported by the Aeronautical Science Foundation of China(2017ZC53033)the Seed Foundation of Innovation and Creation for Graduate Students in Northwestern Polytechnical University(CX2020156)。
文摘In order to improve the autonomous ability of unmanned aerial vehicles(UAV)to implement air combat mission,many artificial intelligence-based autonomous air combat maneuver decision-making studies have been carried out,but these studies are often aimed at individual decision-making in 1 v1 scenarios which rarely happen in actual air combat.Based on the research of the 1 v1 autonomous air combat maneuver decision,this paper builds a multi-UAV cooperative air combat maneuver decision model based on multi-agent reinforcement learning.Firstly,a bidirectional recurrent neural network(BRNN)is used to achieve communication between UAV individuals,and the multi-UAV cooperative air combat maneuver decision model under the actor-critic architecture is established.Secondly,through combining with target allocation and air combat situation assessment,the tactical goal of the formation is merged with the reinforcement learning goal of every UAV,and a cooperative tactical maneuver policy is generated.The simulation results prove that the multi-UAV cooperative air combat maneuver decision model established in this paper can obtain the cooperative maneuver policy through reinforcement learning,the cooperative maneuver policy can guide UAVs to obtain the overall situational advantage and defeat the opponents under tactical cooperation.
基金This work was supported by the National“863”High Pro-gram of China(No.2002AA331112)the Doctorate Foun-dation of Northwestern Polytechnical University(CX200409)the Science Research Foundation of Henan University of Science and Technology(No.2004ZY039).
文摘The structure and properties of Cu-Cr-Zr alloy were studied after rapidly solidified aging and solid solution aging.At the early stage of aging （500℃ for 15 rain）, the hardness and the conductivity of the alloy rapidly solidified are 143 HV and 72% IACS, respectively. Under the same aging condition, the hardness and electrical conductivity of the alloy solid solution treated can reach 86 HV and 47% IACS, respectively. The microstructure was analyzed, and the grain size after rapid solidification is much smaller than that after solid solution treatment. By rapidly solidified aging the fine precipitates distribute inside the grains and along the grain boundary, while by solid solution aging there are large Cr particles along the grain boundary.
基金supported by the National Basic Research Program of China (973 Program, Grant No. 2006CB202308)
文摘Located in the middle of the Tarim Basin, Tazhong is a typical area of compound reservoirs rich in oil and gas found in the Carboniferous, Silurian and Ordovician strata. The proved, probable and possible reserves （3P reserves） in the area amount to 5×108 tons, so it is of great significance to study the advances and problems in hydrocarbon exploration in the Tazhong area. On the basis of exploration history and analysis of scientific problems, we outline eight achievements： distribution characteristics of reservoirs, stages of reservoir formation, different sources of oil and gas and their respective contributions, the effective regional caprock and reservoir-caprock combinations dominating the vertical distribution of hydrocarbon reservoirs, the control of the Tazhong Palaeo-uplift on reservoir formation and establishing geologic models, structure balance belts influencing the reconstruction and residual potential of reservoirs after accumulation, the rules and mechanisms of fractures controlling oil and gas, and the types of favorable reservoirs and their characteristics of controlling oil and gas distribution. We further point out the main problems about the oil and gas exploration in the Tazhong area and put forward some relevant proposals.
基金supported by the National Natural Science Foundation of China (No.81373342)Beijing Natural Science Foundation (Nos.2141004 and 7142114)
文摘The efficacy of chemotherapeutic drug in cancer treatment is often hampered by drug resistance of tumor cells,which is usually caused by abnormal gene expression.RNA interference mediated by si RNA and mi RNA can selectively knock down the carcinogenic genes by targeting specific m RNAs.Therefore,combining chemotherapeutic drugs with gene agents could be a promising strategy for cancer therapy.Due to poor stability and solubility associated with gene agents and drugs,suitable protective carriers are needed and have been widely researched for the co-delivery.In this review,we summarize the most commonly used nanocarriers for co-delivery of chemotherapeutic drugs and gene agents,as well as the advances in co-delivery systems.
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has spread rapidly throughout the world.SARS-CoV-2 is an enveloped,plus-stranded RNA virus with a single-stranded RNA genome of approximately 30,000 nucleotides.The SARS-CoV-2 genome encodes 29 proteins,including 16 nonstructural,4 structural and 9 accessory proteins.To date,over 1,228 experimental structures of SARS-CoV-2 proteins have been deposited in the Protein Data Bank(PDB),including 16 protein structures,two functional domain structures of nucleocapsid(N)protein,and scores of complexes.Overall,they exhibit high similarity to SARS-CoV proteins.Here,we summarize the progress of structural and functional research on SARS-CoV-2 proteins.These studies provide structural and functional insights into proteins of SARS-CoV-2,and further elucidate the daedal relationship between different components at the atomic level in the viral life cycle,including attachment to the host cell,viral genome replication and transcription,genome packaging and assembly,and virus release.It is important to understand the structural and functional properties of SARS-CoV-2 proteins as it will facilitate the development of anti-CoV drugs and vaccines to prevent and control the current SARS-CoV-2 pandemic.
