Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the tr...Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with exte展开更多
Recently, the emergence of pre-trained models(PTMs) has brought natural language processing(NLP) to a new era. In this survey, we provide a comprehensive review of PTMs for NLP. We first briefly introduce language rep...Recently, the emergence of pre-trained models(PTMs) has brought natural language processing(NLP) to a new era. In this survey, we provide a comprehensive review of PTMs for NLP. We first briefly introduce language representation learning and its research progress. Then we systematically categorize existing PTMs based on a taxonomy from four different perspectives. Next,we describe how to adapt the knowledge of PTMs to downstream tasks. Finally, we outline some potential directions of PTMs for future research. This survey is purposed to be a hands-on guide for understanding, using, and developing PTMs for various NLP tasks.展开更多
At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL ...At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved： graphene quantum dots （GQDs）, carbon nanodots （CNDs）, and polymer dots （PDs）. Four reasonable PL mechanisms have been confirmed： the quantum confinement effect or conjugated 7x-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink- enhanced emission （CEE） effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.展开更多
Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9...Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9%）, 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.展开更多
Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous Jul...Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous July to current June in the recent 1000 years was re- constructed for Delingha. The reconstruction can capture 63.1% of precipitation variance and the equation was stable over time. For the reconstructed precipitation, wet periods occurred in AD1520—1633 and 1933—2001, whereas dry intervals in 1429—1519 and 1634—1741. In ad- dition, the magnitude in precipitation variation was lower before 1430 with about 15 mm, but it increased to 30 mm during the period of 1430 to 1850. After 1850, the precipitation variance de- creased again. In contrast to the increase in temperature, a decrease in annual precipitation was evident since the 1990s. The agreement in low-frequency variation between the reconstruction and the glacier accumulation and particulate content in Dunde ice cores during the recent several hundred years suggested that the precipitation reconstructed in this study was rather reliable, and represented a regional signal. This 1000-year reconstruction could benefit our understanding of climatic variation in decadal to century-scale in this region, and provide basic data to climate models and to prediction of future climate in the 21st century.展开更多
INTRODUCTIONIn China ,the incidence and mortality of gastric cancer rank the second among all cancers. Recent development of cancer [1-20].The aim of this study was investigat the insight of apoptosis and bcl-2, p53 a...INTRODUCTIONIn China ,the incidence and mortality of gastric cancer rank the second among all cancers. Recent development of cancer [1-20].The aim of this study was investigat the insight of apoptosis and bcl-2, p53 and C-myc protein expression in the development of gastric cancer .展开更多
Traditional Chinese Medicine（TCM）, a crucial component of the current medical system, has been extensively used in clinical practice due to its valuable therapeutic efficacy, and its potentials as an important sourc...Traditional Chinese Medicine（TCM）, a crucial component of the current medical system, has been extensively used in clinical practice due to its valuable therapeutic efficacy, and its potentials as an important source of new pharmacophores. TCM is characterized by holistic theory, which emphasizes maintaining the balance of the patient＇s whole body using herbal formulae（fangji in Chinese） composed of mixtures of herbs with multiple bioactive ingredients. Because of the complex nature of these formulae, it is necessary to develop systematic methods to identify their bioactive ingredients and to clarify their mechanisms of action. With the rapid progress in bioinformatics, systems biology, and polypharmacology, ＂network pharmacology＂, which shifts the ＂one target, one drug＂ paradigm to the ＂network target, multi-component＂ strategy, has attracted the attention because it can not only reveal the underlying complex interactions between a herbal formula and cellular proteins but detect the influence of their interactions on the function and behavior of the system. Growing evidence shows that the network pharmacology strategy can be a powerful approach to modern research on TCM. The present paper focuses on the basis of network pharmacology and the recent progress in its methodology, illustrates its utility in screening bioactive ingredients and elucidating the mechanisms of action of TCM herbal formulae, analyzes its limitations and problems, and discusses its development direction and application prospects.展开更多
Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain ...Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters （PMzs） from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon （EC） and organic carbon （OC） was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum （GC-MS）. Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols （0.18%-0.63% of the total fine particle mass）. Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index （CPI） of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.展开更多
Traditional Chinese medicine(TCM)is a precious treasure of the Chinese nation and has unique advantages in the prevention and treatment of diseases.The holistic view of TCM coincides with the new generation of medical...Traditional Chinese medicine(TCM)is a precious treasure of the Chinese nation and has unique advantages in the prevention and treatment of diseases.The holistic view of TCM coincides with the new generation of medical research paradigm characterized by network and system.TCM gave birth to a new method featuring holistic and systematic"network target",a core theory and method of network pharmacology.TCM is also an important research object of network pharmacology.TCM network pharmacology,which aims to understand the network-based biological basis of complex diseases,TCM syndromes and herb treatments,plays a critical role in the origin and development process of network pharmacology.This review introduces new progresses of TCM network pharmacology in recent years,including predicting herb targets,understanding biological foundation of diseases and syndromes,network regulation mechanisms of herbal formulae,and identifying disease and syndrome biomarkers based on biological network.These studies show a trend of combining computational,experimental and clinical approaches,which is a promising direction of TCM network pharmacology research in the future.Considering that TCM network pharmacology is still a young research field,it is necessary to further standardize the research process and evaluation indicators to promote its healthy development.展开更多
Wnt signaling transduces evolutionarily conserved pathways which play important roles in initiating and regulating a diverse range of cellular activities,including cell proliferation,calcium homeostasis,and cell polar...Wnt signaling transduces evolutionarily conserved pathways which play important roles in initiating and regulating a diverse range of cellular activities,including cell proliferation,calcium homeostasis,and cell polarity.The role of Wnt signaling in controlling cell proliferation and stem cell self-renewal is primarily carried out through the canonical pathway,which is the best-characterized the multiple Wnt signaling branches.The past 10 years has seen a rapid expansion in our understanding of the complexity of this pathway,as many new components of Wnt signaling have been identified and linked to signaling regulation,stem cell functions,and adult tissue homeostasis.Additionally,a substantial body of evidence links Wnt signaling to tumorigenesis of cancer types and implicates it in the development of cancer drug resistance.Thus,a better understanding of the mechanisms by which dysregulation of Wnt signaling precedes the development and progression of human cancer may hasten the development of pathway inhibitors to augment current therapy.This review summarizes and synthesizes our current knowledge of the canonical Wnt pathway in development and disease.We begin with an overview of the components of the canonical Wnt signaling pathway and delve into the role this pathway has been shown to play in stemness,tumorigenesis,and cancer drug resistance.Ultimately,we hope to present an organized collection of evidence implicating Wnt signaling in tumorigenesis and chemoresistance to facilitate the pursuit of Wnt pathway modulators that may improve outcomes of cancers in which Wnt signaling contributes to aggressive disease and/or treatment resistance.展开更多
A high-resolution oxygen-isotope record from a thorium-uranium-dated stalagmite from Shanbao Cave at Shennongjia reflects variations in the amount of monsoon precipitation for the period from 11.5 to 2.1 ka (1 ka = 10...A high-resolution oxygen-isotope record from a thorium-uranium-dated stalagmite from Shanbao Cave at Shennongjia reflects variations in the amount of monsoon precipitation for the period from 11.5 to 2.1 ka (1 ka = 1000 cal aBP). Between 11.5 and 9.3 ka, a sharp decrease in δ18O indicates a rapid increase in monsoon precipitation. An interval of generally high monsoon precipitation is observed between 9.3 and 4.4 ka. An arid period has prevailed between 4.4 and 2.1 ka. The long-term trend of Shanbao record appears to follow summer insolation at 33°N latitude. An abrupt decrease in monsoon precipitation around 4.3 ka is synchronous with the collapse of Neolithic culture in central China. This abrupt change could have resulted from the amplifi- cation of the gradually decreased summer insolation by the positive vegetation-atmosphere-aerosol feed- back. The weakened Asian monsoon events were in concert with decreased Greenland temperature dur- ing the early Holocene, centered at 8.2, 8.6, 9.3, 10.2 and 11.0 ka. This correlation suggests that changes in low-latitude monsoon are connected with climate change in high-latitude polar region.展开更多
Based on the cross-dated tree-ring samples collected from the middle Qilian Moun- tain, a standard ring-width chronology had been developed, which covered the period AD 1000 to 2000. The correlations between the chron...Based on the cross-dated tree-ring samples collected from the middle Qilian Moun- tain, a standard ring-width chronology had been developed, which covered the period AD 1000 to 2000. The correlations between the chronology and climatic records from the nearby meteorological stations indicated that temperature was the dominant climatic factor for tree growth at upper timberline, and the most important climatic factor for the tree growth in the area was the mean temperature from previous December to current April. The temperature variations recovered from the ring-width data showed a cold period during the “Little Ice Age” and the con- tinuous warming during the twentieth century. Comparison between the ring-width chronology and δ18O records from the Dunde ice core in the Qilian Mountain indicated that there was a con- sistent trend in both time series. A significant correlation existed between our ring-width chro- nology and the Northern Hemispheric temperature, suggesting that the climate changes in the Qilian Mountain were not only driven by regional factors, but also responsive to the global cli- mate.展开更多
MAP kinases transduce signals that are involved in a multitude of cellular pathways and functions in response to a variety of ligands and cell stimuli. Aberrant or inappropriate functions of MAPKs have now been identi...MAP kinases transduce signals that are involved in a multitude of cellular pathways and functions in response to a variety of ligands and cell stimuli. Aberrant or inappropriate functions of MAPKs have now been identified in diseases ranging from cancer to inflammatory disease to obesity and diabetes. In many cell types, the MAPKs ERK1/2 are linked to cell proliferation. ERK1/2 are thought to play a role in some cancers, because mutations in Ras and B-Raf, which can activate the ERK1/2 cascade, are found in many human tumors. Abnormal ERK1/2 signaling has also been found in polycystic kidney disease, and serious developmental disorders such as cardio-facio-cutaneous syndrome arise from mutations in components of the ERK1/2 cascade. ERK1/2 are essential in well-differentiated cells and have been linked to long-term potentiation in neurons and in maintenance of epithelial polarity. Additionally, ERK1/2 are important for insulin gene transcription in pancreatic beta cells, which produce insulin in response to increases in circulating glucose to permit efficient glucose utilization and storage in the organism. Nutrients and hormones that induce or repress insulin secretion activate and/or inhibit ERK1/2 in a manner that reflects the secretory demand on beta cells. Disturbances in this and other regulatory pathways may result in the contribution of ERK1/2 to the etiology of certain human disorders.展开更多
Objective To investigate the trends of lipid profiles and dyslipidemia among Chinese adults from 2002 to 2015.Methods Data were collected from three nationally representative cross-sectional surveys.Fasting venous blo...Objective To investigate the trends of lipid profiles and dyslipidemia among Chinese adults from 2002 to 2015.Methods Data were collected from three nationally representative cross-sectional surveys.Fasting venous blood samples were collected and serum lipids were tested by biochemical analysis and enzymatic determination.Lipid levels and the prevalence of dyslipidemia among adults were analyzed with complex sampling weighting adjustment for age and gender.Results The weighted means of TC, TG, and LDL-c significantly increased linearly from 3.93, 1.12, and 2.12 mmol/L in 2002 to 4.59, 1.41, and 2.78 mmol/L in 2010 and then to 4.63, 1.47, and 2.87 mmol/L in 2015, respectively;by contrast, HDL-c levels decreased significantly from 1.30 mmol/L to 1.26 mmol/L over the same period.Similar trends in mean non-HDL-c and lipid-related ratios were observed.The weighted dyslipidemia prevalence linearly increased;in particular, hypercholesterolemia increased from 1.6% to 5.6% and then to 5.8%, hypertriglyceridemia increased from 5.7% to 13.6% and then to 15.0%, low HDL-c increased from 18.8% to 35.5% and then to 24.9%, and high LDL-c increased from 1.3% to 5.6% and then to 7.2%(P for trend <0.001).Conclusion Dyslipidemia increased among Chinese adults from 2002 to 2015.Development of a comprehensive strategy to decrease lipid levels in this population is urgently required.展开更多
Transformers have recently lead to encouraging progress in computer vision.In this work,we present new baselines by improving the original Pyramid Vision Transformer(PVT v1)by adding three designs:(i)a linear complexi...Transformers have recently lead to encouraging progress in computer vision.In this work,we present new baselines by improving the original Pyramid Vision Transformer(PVT v1)by adding three designs:(i)a linear complexity attention layer,(ii)an overlapping patch embedding,and(iii)a convolutional feed-forward network.With these modifications,PVT v2 reduces the computational complexity of PVT v1 to linearity and provides significant improvements on fundamental vision tasks such as classification,detection,and segmentation.In particular,PVT v2 achieves comparable or better performance than recent work such as the Swin transformer.We hope this work will facilitate state-ofthe-art transformer research in computer vision.Code is available at https://github.com/whai362/PVT.展开更多
Foreword Note:Some of the document contents may involve certain patents,the identification of which is not the responsibility of the institution that releases the document.Main drafting organizations:Tsinghua Universi...Foreword Note:Some of the document contents may involve certain patents,the identification of which is not the responsibility of the institution that releases the document.Main drafting organizations:Tsinghua University,Specialty Committee of Network Pharmacology of World Federation of Chinese Medicine Societies(WFCMS).展开更多
Stable and safe operation of power grids is an important guarantee for economy development.Support Vector Machine(SVM)based stability analysis method is a significant method started in the last century.However,the SVM...Stable and safe operation of power grids is an important guarantee for economy development.Support Vector Machine(SVM)based stability analysis method is a significant method started in the last century.However,the SVM method has several drawbacks,e.g.low accuracy around the hyperplane and heavy computational burden when dealing with large amount of data.To tackle the above problems of the SVM model,the algorithm proposed in this paper is optimized from three aspects.Firstly,the gray area of the SVM model is judged by the probability output and the corresponding samples are processed.Therefore the clustering of the samples in the gray area is improved.The problem of low accuracy in the training of the SVM model in the gray area is improved,while the size of the sample is reduced and the efficiency is improved.Finally,by adjusting the model of the penalty factor in the SVM model after the clustering of the samples,the number of samples with unstable states being misjudged as stable is reduced.Test results on the IEEE 118-bus test system verify the proposed method.展开更多
AIM: To carry out a hospital-based case-control study to investigate risk factors for intrahepatic cholangiocarcinoma (ICC) in China. METHODS: A total of 312 ICC cases and 438 matched controls were included in the stu...AIM: To carry out a hospital-based case-control study to investigate risk factors for intrahepatic cholangiocarcinoma (ICC) in China. METHODS: A total of 312 ICC cases and 438 matched controls were included in the study. The presence of diabetes mellitus,hypertention,hepatolithiasis,primary sclerosing cholangitis,liver fluke infection (Clonorchis sinensis ),was investigated through clinical records. Blood from all participants was tested for hepatitis B surface antigen (HBsAg) and anti-HCV antibodies. Odds ratios (OR) and 95% confi dence intervals (95% CI) were estimated using conditional logistic regression. RESULTS: Compared with controls,ICC patients had a higher prevalence of HBsAg seropositivity (48.4% vs 9.6%,P < 0.000),and hepatolithiasis (5.4% vs 1.1%,P = 0.001). By multivariate analysis,the signif icant risk factors for development of ICC were HBsAg seropositivity (adjusted OR,8.876,95% CI,5.973-13.192),and hepatolithiasis (adjusted OR,5.765,95% CI,1.972-16.851). The prevalence of anti-HCV seropositivity,diabetes mellitus,hypertention,cigarette smoking,and alcohol consumption were not significantly different between cases and controls. CONCLUSION: These findings suggest that HBV infection and hepatolithiasis are strong risk factors for development of ICC in China.展开更多
基金Supported in part by the Offices of NP and HEP within the U.S.DOE Office of Sciencethe U.S.NSF+18 种基金the Sloan Foundationthe DFG cluster of excellence‘Origin and Structure of the Universe’of Germany,CNRS/IN2P3STFC and EPSRC of the United KingdomFAPESP CNPq of Brazil,Ministry of Ed.Sci.of the Russian FederationNNSFCCASMoSTMoE of ChinaGA and MSMT of the Czech RepublicFOM and NWO of the NetherlandsDAEDSTCSIR of IndiaPolish Ministry of Sci.Higher Ed.,Korea Research Foundation,Ministry of Sci.,Ed.Sports of the Rep.Of CroatiaRussian Ministry of Sci.and TechRos-Atom of Russia。
文摘Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with exte
基金the National Natural Science Foundation of China(Grant Nos.61751201 and 61672162)the Shanghai Municipal Science and Technology Major Project(Grant No.2018SHZDZX01)and ZJLab。
文摘Recently, the emergence of pre-trained models(PTMs) has brought natural language processing(NLP) to a new era. In this survey, we provide a comprehensive review of PTMs for NLP. We first briefly introduce language representation learning and its research progress. Then we systematically categorize existing PTMs based on a taxonomy from four different perspectives. Next,we describe how to adapt the knowledge of PTMs to downstream tasks. Finally, we outline some potential directions of PTMs for future research. This survey is purposed to be a hands-on guide for understanding, using, and developing PTMs for various NLP tasks.
文摘At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved： graphene quantum dots （GQDs）, carbon nanodots （CNDs）, and polymer dots （PDs）. Four reasonable PL mechanisms have been confirmed： the quantum confinement effect or conjugated 7x-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink- enhanced emission （CEE） effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.
基金This work was supported by the project of Yunnan Innovation Team Project, the Hundreds Oversea Talents Program of Yunnan Province, the Top Talents Program of Yunnan Province （Grant 20080A009）, the Key Project of the Natural Science Foundation of Yunnan Province （201401 PC00397）, National Science Foundation of China （U0936603）, Key Project of Natural Science Foundation of Yunnan Province （2008CC016）, Frontier Grant of Kunming Institute of Botany, CAS （672705232515）, Top Talents Program of Yunnan Province （20080A009）, and Hundreds Talents Program of Chinese Academy of Sciences （CAS） （to L.G.）.
文摘Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9%）, 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.
基金the National KeyBasic Research Development Project of China(Grant No.19980408)the Key Project of Knowledge Innovation of the CAs(Grant No.KZcx2-314) the National Key Project of Science and Technology(Grant No.2001-BA611B-O1).
文摘Using seven well-replicated Qilian juniper (Sabina przewalskii Kom.) ring-width chronologies developed at Zongwulong and Shalike Mts. in the northeastern part of the Qaidam Basin annual precipitation from previous July to current June in the recent 1000 years was re- constructed for Delingha. The reconstruction can capture 63.1% of precipitation variance and the equation was stable over time. For the reconstructed precipitation, wet periods occurred in AD1520—1633 and 1933—2001, whereas dry intervals in 1429—1519 and 1634—1741. In ad- dition, the magnitude in precipitation variation was lower before 1430 with about 15 mm, but it increased to 30 mm during the period of 1430 to 1850. After 1850, the precipitation variance de- creased again. In contrast to the increase in temperature, a decrease in annual precipitation was evident since the 1990s. The agreement in low-frequency variation between the reconstruction and the glacier accumulation and particulate content in Dunde ice cores during the recent several hundred years suggested that the precipitation reconstructed in this study was rather reliable, and represented a regional signal. This 1000-year reconstruction could benefit our understanding of climatic variation in decadal to century-scale in this region, and provide basic data to climate models and to prediction of future climate in the 21st century.
基金Supported by the Medical Research Foundation of Guangdong Province,No.1997423
文摘INTRODUCTIONIn China ,the incidence and mortality of gastric cancer rank the second among all cancers. Recent development of cancer [1-20].The aim of this study was investigat the insight of apoptosis and bcl-2, p53 and C-myc protein expression in the development of gastric cancer .
基金National Natural Science Foundation of China(81225025)Beijing Nova Program(Z1511000003150126)
文摘Traditional Chinese Medicine（TCM）, a crucial component of the current medical system, has been extensively used in clinical practice due to its valuable therapeutic efficacy, and its potentials as an important source of new pharmacophores. TCM is characterized by holistic theory, which emphasizes maintaining the balance of the patient＇s whole body using herbal formulae（fangji in Chinese） composed of mixtures of herbs with multiple bioactive ingredients. Because of the complex nature of these formulae, it is necessary to develop systematic methods to identify their bioactive ingredients and to clarify their mechanisms of action. With the rapid progress in bioinformatics, systems biology, and polypharmacology, ＂network pharmacology＂, which shifts the ＂one target, one drug＂ paradigm to the ＂network target, multi-component＂ strategy, has attracted the attention because it can not only reveal the underlying complex interactions between a herbal formula and cellular proteins but detect the influence of their interactions on the function and behavior of the system. Growing evidence shows that the network pharmacology strategy can be a powerful approach to modern research on TCM. The present paper focuses on the basis of network pharmacology and the recent progress in its methodology, illustrates its utility in screening bioactive ingredients and elucidating the mechanisms of action of TCM herbal formulae, analyzes its limitations and problems, and discusses its development direction and application prospects.
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2001AA641060 2003AA641040)the National Basic Research Program (973) of China (No. 2002CB410801).
文摘Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters （PMzs） from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon （EC） and organic carbon （OC） was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum （GC-MS）. Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols （0.18%-0.63% of the total fine particle mass）. Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index （CPI） of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.
基金supported by the National Natural Science Foundation of China(Nos.6201101081,81630103 and 81225025)Tsinghua University Spring Breeze Fund(No.2020-Z99CFY040)Beijing National Research Center for Information Science and Technology(Nos.BNR2019TD01020 and BNR2019-RC01012)。
文摘Traditional Chinese medicine(TCM)is a precious treasure of the Chinese nation and has unique advantages in the prevention and treatment of diseases.The holistic view of TCM coincides with the new generation of medical research paradigm characterized by network and system.TCM gave birth to a new method featuring holistic and systematic"network target",a core theory and method of network pharmacology.TCM is also an important research object of network pharmacology.TCM network pharmacology,which aims to understand the network-based biological basis of complex diseases,TCM syndromes and herb treatments,plays a critical role in the origin and development process of network pharmacology.This review introduces new progresses of TCM network pharmacology in recent years,including predicting herb targets,understanding biological foundation of diseases and syndromes,network regulation mechanisms of herbal formulae,and identifying disease and syndrome biomarkers based on biological network.These studies show a trend of combining computational,experimental and clinical approaches,which is a promising direction of TCM network pharmacology research in the future.Considering that TCM network pharmacology is still a young research field,it is necessary to further standardize the research process and evaluation indicators to promote its healthy development.
基金The authors’research efforts were supported in part by research grants from the NIH(AT004418 to TCH)the 973 Program of Ministry of Science and Technology(MOST)of China(#2011CB707900 to TCH)+1 种基金the Scoliosis Research Society(to MJL),MKM was a recipient of Howard Hughes Medical Institute Medical Research FellowshipCS was a recipient of the Pritzker Summer Research Fellowship funded through a NIH T-35 training grant(NIDDK).
文摘Wnt signaling transduces evolutionarily conserved pathways which play important roles in initiating and regulating a diverse range of cellular activities,including cell proliferation,calcium homeostasis,and cell polarity.The role of Wnt signaling in controlling cell proliferation and stem cell self-renewal is primarily carried out through the canonical pathway,which is the best-characterized the multiple Wnt signaling branches.The past 10 years has seen a rapid expansion in our understanding of the complexity of this pathway,as many new components of Wnt signaling have been identified and linked to signaling regulation,stem cell functions,and adult tissue homeostasis.Additionally,a substantial body of evidence links Wnt signaling to tumorigenesis of cancer types and implicates it in the development of cancer drug resistance.Thus,a better understanding of the mechanisms by which dysregulation of Wnt signaling precedes the development and progression of human cancer may hasten the development of pathway inhibitors to augment current therapy.This review summarizes and synthesizes our current knowledge of the canonical Wnt pathway in development and disease.We begin with an overview of the components of the canonical Wnt signaling pathway and delve into the role this pathway has been shown to play in stemness,tumorigenesis,and cancer drug resistance.Ultimately,we hope to present an organized collection of evidence implicating Wnt signaling in tumorigenesis and chemoresistance to facilitate the pursuit of Wnt pathway modulators that may improve outcomes of cancers in which Wnt signaling contributes to aggressive disease and/or treatment resistance.
基金This work was supported by National Science Foundation of China(Grant No.40225007)The Foundation for the Author of National Excellent Doctoral Dissertation of P.R.China(Grant No.200227).
文摘A high-resolution oxygen-isotope record from a thorium-uranium-dated stalagmite from Shanbao Cave at Shennongjia reflects variations in the amount of monsoon precipitation for the period from 11.5 to 2.1 ka (1 ka = 1000 cal aBP). Between 11.5 and 9.3 ka, a sharp decrease in δ18O indicates a rapid increase in monsoon precipitation. An interval of generally high monsoon precipitation is observed between 9.3 and 4.4 ka. An arid period has prevailed between 4.4 and 2.1 ka. The long-term trend of Shanbao record appears to follow summer insolation at 33°N latitude. An abrupt decrease in monsoon precipitation around 4.3 ka is synchronous with the collapse of Neolithic culture in central China. This abrupt change could have resulted from the amplifi- cation of the gradually decreased summer insolation by the positive vegetation-atmosphere-aerosol feed- back. The weakened Asian monsoon events were in concert with decreased Greenland temperature dur- ing the early Holocene, centered at 8.2, 8.6, 9.3, 10.2 and 11.0 ka. This correlation suggests that changes in low-latitude monsoon are connected with climate change in high-latitude polar region.
基金supported by the Major Knowiedge Innovation Project of the Chinese Aademy of Sciences(Gant Nos.KZCX1-1002 and KZCX1-1009)the opening fund of the Key Laboratory of Ice-core and Cold-regions Environment,Cold and Arid Regions Environment and Engineering Research Insti tute,Chinese Academy ofSciences(Grant No.210506)..
文摘Based on the cross-dated tree-ring samples collected from the middle Qilian Moun- tain, a standard ring-width chronology had been developed, which covered the period AD 1000 to 2000. The correlations between the chronology and climatic records from the nearby meteorological stations indicated that temperature was the dominant climatic factor for tree growth at upper timberline, and the most important climatic factor for the tree growth in the area was the mean temperature from previous December to current April. The temperature variations recovered from the ring-width data showed a cold period during the “Little Ice Age” and the con- tinuous warming during the twentieth century. Comparison between the ring-width chronology and δ18O records from the Dunde ice core in the Qilian Mountain indicated that there was a con- sistent trend in both time series. A significant correlation existed between our ring-width chro- nology and the Northern Hemispheric temperature, suggesting that the climate changes in the Qilian Mountain were not only driven by regional factors, but also responsive to the global cli- mate.
文摘MAP kinases transduce signals that are involved in a multitude of cellular pathways and functions in response to a variety of ligands and cell stimuli. Aberrant or inappropriate functions of MAPKs have now been identified in diseases ranging from cancer to inflammatory disease to obesity and diabetes. In many cell types, the MAPKs ERK1/2 are linked to cell proliferation. ERK1/2 are thought to play a role in some cancers, because mutations in Ras and B-Raf, which can activate the ERK1/2 cascade, are found in many human tumors. Abnormal ERK1/2 signaling has also been found in polycystic kidney disease, and serious developmental disorders such as cardio-facio-cutaneous syndrome arise from mutations in components of the ERK1/2 cascade. ERK1/2 are essential in well-differentiated cells and have been linked to long-term potentiation in neurons and in maintenance of epithelial polarity. Additionally, ERK1/2 are important for insulin gene transcription in pancreatic beta cells, which produce insulin in response to increases in circulating glucose to permit efficient glucose utilization and storage in the organism. Nutrients and hormones that induce or repress insulin secretion activate and/or inhibit ERK1/2 in a manner that reflects the secretory demand on beta cells. Disturbances in this and other regulatory pathways may result in the contribution of ERK1/2 to the etiology of certain human disorders.
基金supported by the National Health and Family Planning Commission(formerly the Ministry of Health of the People’s Republic of China)Medical Reform Major Program:China Nutrition and Health Surveillance(2010-2012)and Chinese Adults Chronic Diseases and Nutrition Surveillance(2015)
文摘Objective To investigate the trends of lipid profiles and dyslipidemia among Chinese adults from 2002 to 2015.Methods Data were collected from three nationally representative cross-sectional surveys.Fasting venous blood samples were collected and serum lipids were tested by biochemical analysis and enzymatic determination.Lipid levels and the prevalence of dyslipidemia among adults were analyzed with complex sampling weighting adjustment for age and gender.Results The weighted means of TC, TG, and LDL-c significantly increased linearly from 3.93, 1.12, and 2.12 mmol/L in 2002 to 4.59, 1.41, and 2.78 mmol/L in 2010 and then to 4.63, 1.47, and 2.87 mmol/L in 2015, respectively;by contrast, HDL-c levels decreased significantly from 1.30 mmol/L to 1.26 mmol/L over the same period.Similar trends in mean non-HDL-c and lipid-related ratios were observed.The weighted dyslipidemia prevalence linearly increased;in particular, hypercholesterolemia increased from 1.6% to 5.6% and then to 5.8%, hypertriglyceridemia increased from 5.7% to 13.6% and then to 15.0%, low HDL-c increased from 18.8% to 35.5% and then to 24.9%, and high LDL-c increased from 1.3% to 5.6% and then to 7.2%(P for trend <0.001).Conclusion Dyslipidemia increased among Chinese adults from 2002 to 2015.Development of a comprehensive strategy to decrease lipid levels in this population is urgently required.
基金National Natural Science Foundation of China under Grant Nos.61672273 and 61832008Science Foundation for Distinguished Young Scholars of Jiangsu under Grant No.BK20160021+1 种基金Postdoctoral Innovative Talent Support Program of China under Grant Nos.BX20200168,2020M681608General Research Fund of Hong Kong under Grant No.27208720。
文摘Transformers have recently lead to encouraging progress in computer vision.In this work,we present new baselines by improving the original Pyramid Vision Transformer(PVT v1)by adding three designs:(i)a linear complexity attention layer,(ii)an overlapping patch embedding,and(iii)a convolutional feed-forward network.With these modifications,PVT v2 reduces the computational complexity of PVT v1 to linearity and provides significant improvements on fundamental vision tasks such as classification,detection,and segmentation.In particular,PVT v2 achieves comparable or better performance than recent work such as the Swin transformer.We hope this work will facilitate state-ofthe-art transformer research in computer vision.Code is available at https://github.com/whai362/PVT.
文摘Foreword Note:Some of the document contents may involve certain patents,the identification of which is not the responsibility of the institution that releases the document.Main drafting organizations:Tsinghua University,Specialty Committee of Network Pharmacology of World Federation of Chinese Medicine Societies(WFCMS).
基金This work was supported by China’s National key research and development program 2017YFB0902201National Natural Science Foundation of China under Grant 51777104Science and Technology Project of the State Grid Corporation of China.
文摘Stable and safe operation of power grids is an important guarantee for economy development.Support Vector Machine(SVM)based stability analysis method is a significant method started in the last century.However,the SVM method has several drawbacks,e.g.low accuracy around the hyperplane and heavy computational burden when dealing with large amount of data.To tackle the above problems of the SVM model,the algorithm proposed in this paper is optimized from three aspects.Firstly,the gray area of the SVM model is judged by the probability output and the corresponding samples are processed.Therefore the clustering of the samples in the gray area is improved.The problem of low accuracy in the training of the SVM model in the gray area is improved,while the size of the sample is reduced and the efficiency is improved.Finally,by adjusting the model of the penalty factor in the SVM model after the clustering of the samples,the number of samples with unstable states being misjudged as stable is reduced.Test results on the IEEE 118-bus test system verify the proposed method.
文摘AIM: To carry out a hospital-based case-control study to investigate risk factors for intrahepatic cholangiocarcinoma (ICC) in China. METHODS: A total of 312 ICC cases and 438 matched controls were included in the study. The presence of diabetes mellitus,hypertention,hepatolithiasis,primary sclerosing cholangitis,liver fluke infection (Clonorchis sinensis ),was investigated through clinical records. Blood from all participants was tested for hepatitis B surface antigen (HBsAg) and anti-HCV antibodies. Odds ratios (OR) and 95% confi dence intervals (95% CI) were estimated using conditional logistic regression. RESULTS: Compared with controls,ICC patients had a higher prevalence of HBsAg seropositivity (48.4% vs 9.6%,P < 0.000),and hepatolithiasis (5.4% vs 1.1%,P = 0.001). By multivariate analysis,the signif icant risk factors for development of ICC were HBsAg seropositivity (adjusted OR,8.876,95% CI,5.973-13.192),and hepatolithiasis (adjusted OR,5.765,95% CI,1.972-16.851). The prevalence of anti-HCV seropositivity,diabetes mellitus,hypertention,cigarette smoking,and alcohol consumption were not significantly different between cases and controls. CONCLUSION: These findings suggest that HBV infection and hepatolithiasis are strong risk factors for development of ICC in China.
