Myocardial infarction (MI), the most serious of the ischemic heart diseases, is accompanied by myocardial metabolic disorders and the loss of cardiomyocytes. Increasing evidence has shown that long noncoding RNAs (lnc...Myocardial infarction (MI), the most serious of the ischemic heart diseases, is accompanied by myocardial metabolic disorders and the loss of cardiomyocytes. Increasing evidence has shown that long noncoding RNAs (lncRNAs) are involved in various pathological conditions such as cancer and cardiovascular diseases (CVDs), and are emerging as a novel biomarker for these disorders. This study aims to investigate the regulatory role and mechanisms of lncRNAs in myocardial remodeling in the setting of MI. We find that post-infarcted hearts exhibit a reduction of adenosine triphosphate (ATP) and an alteration of the glucose and lipid metabolism genes cluster of differentiation 36 (CD36), hexokinase 1 (HK1), and clucose transporter 4 (GLUT4), accompanied by cardiomyocyte pyroptosis. We then identify a previously unknown conserved lncRNA, AK009126 (cardiomyocyte pyroptosis-associated lncRNA, CPAL), which is remarkably upregulated in the myocardial border zone of MI mice. Importantly, the adeno-associated virus 9 (AAV9)-mediated silencing of endogenous CPAL by its short hairpin RNA (shRNA) partially abrogates myocardial metabolic alterations and cardiomyocyte pyroptosis during MI in mice. Mechanistically, CPAL is shown to bind directly to nuclear factor kappa B (NFκB) and to act as an activator of NFκB to induce NFκB phosphorylation in cardiomyocytes. We also find that CPAL upregulates caspase-1 expression at the transcriptional level and consequently promotes the release of interleukin (IL)-18 and IL-1β from cardiomyocytes. Collectively, our findings reveal the conserved lncRNA CPAL as a new regulator of cardiac metabolic abnormalities and cardiomyocyte pyroptosis in the setting of MI and suggest CPAL as a new therapeutic target to protect cardiomyocytes against ischemic injury in infarcted hearts.展开更多
In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the c...In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.展开更多
Ensemble forecasting has become the prevailing method in current operational weather forecasting. Although ensemble mean forecast skill has been studied for many ensemble prediction systems(EPSs) and different cases...Ensemble forecasting has become the prevailing method in current operational weather forecasting. Although ensemble mean forecast skill has been studied for many ensemble prediction systems(EPSs) and different cases, theoretical analysis regarding ensemble mean forecast skill has rarely been investigated, especially quantitative analysis without any assumptions of ensemble members. This paper investigates fundamental questions about the ensemble mean, such as the advantage of the ensemble mean over individual members, the potential skill of the ensemble mean, and the skill gain of the ensemble mean with increasing ensemble size. The average error coefficient between each pair of ensemble members is the most important factor in ensemble mean forecast skill, which determines the mean-square error of ensemble mean forecasts and the skill gain with increasing ensemble size. More members are useful if the errors of the members have lower correlations with each other, and vice versa. The theoretical investigation in this study is verified by application with the T213 EPS. A typical EPS has an average error coefficient of between 0.5 and 0.8; the 15-member T213 EPS used here reaches a saturation degree of 95%(i.e., maximum 5% skill gain by adding new members with similar skill to the existing members) for 1–10-day lead time predictions, as far as the mean-square error is concerned.展开更多
A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Z...A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Zn O serves as the active sites for the dehydrogenation of ethanol,and CeO_(2) promotes the aldolcondensation reaction.Based on the results of Py-FTIR and NH_(3)-TPD,it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface,given their benefit for aldol-condensation reactions.The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid.Coupling with the Zn O sites,it contributes to a 98.4%conversion of ethanol and a 45.2%selective of 1,3-butadiene under relatively mild reaction conditions(375°C,101.325 k Pa,and 0.54 h^(-1)).展开更多
Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical rol...Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical roles in its seed oil yield,but little is known about how this lignification process is regulated.Here,we report on a comprehensive tissue-specific transcriptomics analysis conducted for C.chekiangoleosa fruit.By mining the differentially expressed genes,we found that lignin biosynthesis and transcriptional regulation pathways were significantly enriched in the lignified tissues.The homolog of NST-like transcription factor,CcNST1,was highly expressed in lignified seed coat and endocarp tissues;transgenic analyses of CcNST1 in Arabidopsis and hybrid poplar revealed the enhanced lignification levels of various tissues.Gene expression analysis of the transgenic lines uncovered potential downstream genes involved in the regulation of lignin biosynthesis.This work provides a valuable gene expression resource and identified the pivotal role of CcNST1 in regulating the lignin biosynthesis underlying fruit lignification.展开更多
Background:Cardiomyocytes derived from human embryonic stem cells(hESCs)are regulated by complex and stringent gene networks during differentiation.Long non-coding RNAs(lncRNAs)exert critical epigenetic regulatory fun...Background:Cardiomyocytes derived from human embryonic stem cells(hESCs)are regulated by complex and stringent gene networks during differentiation.Long non-coding RNAs(lncRNAs)exert critical epigenetic regulatory functions in multiple differentiation processes.However,the involvement of lncRNAs in the differentiation of hESCs into cardiomyocytes has not yet been fully elucidated.Here,we identified the key roles of ZFAS1(lncRNA zinc finger antisense 1)in the differentiation of cardiomyocytes from hESCs.Methods:A model of cardiomyocyte differentiation from stem cells was established using the monolayer differentiation method,and the number of beating hESCs-derived cardiomyocytes was calculated.Gene expression was analyzed by quantitative real-time PCR(qRTPCR).Immunofluorescence assays were performed to assess the expression of cardiac troponin T(cTnT)andα-actinin protein in cardiomyocytes.Results:qRT-PCR showed that ZFAS1 expression in the mesoderm was significantly higher than that in embryonic stem cells,cardiac progenitor cells,and cardiomyocytes.Knockdown of ZFAS1 inhibited cardiomyocyte differentiation from hESCs,which was characterized by reduced expression of the cardiac-specific markers cTnT,α-actinin,myosin heavy chain 6(MYH6),and myosin heavy chain 7(MYH7).In contrast,ZFAS1 overexpression remarkably increased the percentage of spontaneously beating cardiomyocytes.In terms of the mechanism,we found that ZFAS1 is an antisense lncRNA at the 5′end of the protein-coding gene ZNFX1.Knockdown of ZFAS1 could increase the mRNA expression level of ZNFX1.Furthermore,qRT-PCR demonstrated that the silencing of ZNFX1 led to an increase in cardiac-specific markers that predicted the promotion of cardiomyocyte differentiation.Conclusion:Altogether,these data suggest that lncRNA-ZFAS1 is required for cardiac differentiation by functionally inhibiting the expression of ZNFX1,which may provide a reference for the treatment of heart disease to a certain extent.展开更多
Duckweed is a group of aquatic plants with the potential of wastewater remediation and fast accumulation of biomass. The accumulated biomass, rich in cellulose, starch and protein, can be used for biofuel, bio-fertili...Duckweed is a group of aquatic plants with the potential of wastewater remediation and fast accumulation of biomass. The accumulated biomass, rich in cellulose, starch and protein, can be used for biofuel, bio-fertilizer, animal feed and human food. Characterization of natural biodiversity of duckweed species is essential for the germplasm preservation and various practical applications. We have collected samples of duckweed in eastern China and characterized species biodiversity by genotyping, using chloroplast (atpF-atpH and psbK-psbI spacers). Spirodela polyrhiza was revealed as a clear dominant duckweed species in all locations of the area. Other duckweed species were identified as Landoltia punctata, Lemna aequinoctialis and Lemna turionifera. Selected isolates of these four species were used in the experiments to estimate their potential in removing nitrogen and phosphorus nutrients from municipal and industrial wastewater sampled at the local sewage plants. Duckweed was able to reduce the concentration of nitrogen up to 98% and phosphorus up to 96%. The presented data demonstrates high efficiency of the local duckweed isolates for bioremediation of different types of wastewater and the great potential of duckweed for wastewater treatment when incorporated into the purification chain.展开更多
In this work,highly dispersed atomically-thin MoS2 nanosheets were fabricated at one thousandth of the commercial cost using sepiolite(SEP)mineral nanofibers as carriers via a microwave hydrothermal method.Atomresolve...In this work,highly dispersed atomically-thin MoS2 nanosheets were fabricated at one thousandth of the commercial cost using sepiolite(SEP)mineral nanofibers as carriers via a microwave hydrothermal method.Atomresolved microscopy revealed the MoS2 nanosheets were only 1–4 atomic layers thick.The Mo atoms anchored on the mineral surface served as nucleation sites for the nanosheet growth.The MoS2 layers were in staggered stacking yielding abundant atomic steps at the nanosheets’edges,where catalytically active molybdenum terminations dominated instead of the inert sulfur atoms commonly reported.DFT calculations disclosed that the bonding of Mo(MoS2)and O(SEP)at the MoS2/sepiolite(MSEP)interface enabled SEP to be a unique support,superior to the other minerals for growing such highly-dispersed ultrathin MoS2 architecture.In a typical photocatalyisis application,the MSEP demonstrated a significantly improved photocatalytic performance for RhB degradation compared with the MoS2 nanosheets assembled microspheres.This work provides an important new strategy for low-cost batch preparation of high quality 2D materials via assembly on mineral materials.展开更多
Suspended particulate matter(SPM)in lakes exerts strong impact on light propagation,aquatic ecosystem productivity,which co-varies with nutrients,heavy metal and micro-pollutant in waters.In lakes,SPM exerts strong ab...Suspended particulate matter(SPM)in lakes exerts strong impact on light propagation,aquatic ecosystem productivity,which co-varies with nutrients,heavy metal and micro-pollutant in waters.In lakes,SPM exerts strong absorption and backscattering,ultimately affects water leaving signals that can be detected by satellite sensors.Simple regression models based on specific band or hand ratios have been widely used for SPM estimate in the past with moderate accuracy.There are still rooms for model accuracy improvements,and machine learning models may solve the non-linear relationships between spectral variable and SPM in waters.We assembled more than 16,400 in situ measured SPM in lakes from six continents(excluding the Antarctica continent),of which 9640 samples were matched with Landsat overpasses within±7 days.Seven machine learning algorithms and two simple regression methods(linear and partial least squares models)were used to estimate SPM in lakes and the performance were compared.To overcome the problem of imbalance datasets in regression,a Synthetic Minority Over-Sampling technique for regression with Gaussian Noise(SMOGN)was adopted in this study.Through comparison,we found that gradient boosting decision tree(GBDT),random forest(RF),and extreme gradient boosting(XGBoost)models demonstrated good spatiotemporal transferability with SMOGN processed dataset,and has potential to map SPM at different year with good quality of Landsat land surface reflectance images.In all the tested modeling approaches,the GBDT model has accurate calibration(n=6428,R^(2)=0.95,MAPE=29.8%)from SPM collected in 2235 lakes across the world,and the validation(n=3214,R^(2)=0.84,MAPE=38.8%)also exhibited stable performance.Further,the good performances were also exhibited by RF model with calibration(R^(2)=0.93)and validation(R^(2)=0.86,MAPE=24.2%)datasets.We applied GBDT and RF models to map SPM of typical lakes,and satisfactory result was obtained.In addition,the GBDT model was evaluated by historical SPM measurements coincident with different Landsat sensors(L5-TM,L7-ETM+,and L8-OLI),thus the model has the potential to map SPM of lakes for monitoring temporal variations,and tracks lake water SPM dynamics in approximately the past four decades(1984-2021)since Landsat-5/TM was launched in 1984.展开更多
An ultrawideband,polarization-insensitive,metamaterial absorber for oblique angle of incidence is presented using characteristic mode analysis.The absorber consists of conductive meander square loops and symmetric ben...An ultrawideband,polarization-insensitive,metamaterial absorber for oblique angle of incidence is presented using characteristic mode analysis.The absorber consists of conductive meander square loops and symmetric bent metallic strips,which are embedded with lumped resistors.With the aid of modal currents and modal weighting coefficients,the positions of the lumped resistors are determined.After that,the equivalent circuit(EC)model and admittance formula are proposed and analyzed to further understand the working principle and ultrawide bandwidth.The proposed absorber measures an absorption bandwidth of 4.3–26.5 GHz(144.1%in fractional bandwidth)for 90%absorptivity under normal incidence.At the oblique angle of incidence of 45°,the bandwidth of 90%absorptivity is still 5.1–21.3 GHz(122.72%)for transverse electric(TE)polarization,and 6.8–29.5 GHz(125.07%)for transverse magnetic(TM)polarization.The good agreement among simulation,measurement,and EC calculation demonstrates the validity of the proposed method and indicates that the method can be applied to other microwave and optical frequency bands.The proposed metamaterial absorber can be widely applied in electromagnetic compatibility,electromagnetic interference,radar stealth,and biomedical detection.展开更多
Leaf area index(LAI)is an essential climate variable that is crucial to understand the global vegetation change.Long-term satellite LAI products have been applied in many global vegetation change studies.However,these...Leaf area index(LAI)is an essential climate variable that is crucial to understand the global vegetation change.Long-term satellite LAI products have been applied in many global vegetation change studies.However,these LAI products contain various uncertainties that are not been fully considered in current studies.The objective of this study is to explore the uncertainties in the global LAI products and the uncertainty variations.Two global LAI datasets—the European Geoland2 Version 2(GEOV2)and Moderate Resolution Imaging Spectroradiometer(MODIS)(2003-2019)—were investigated.The qualitative quality flags(QQFs)and quantitative quality indicators(QQIs)embedded in the product quality layers were analyzed to identify the temporal anomalies in the quality profile.The results show that the global GEOV2(0.042/10a)and MODIS(0.034/10a)LAI values have steadly increased from 2003 to 2019.The global LAI uncertainty(0.016/10a)and relative uncertainty(0.3%/10a)from GEOV2 have also increased gradually,especially during the growing season from April to October.The uncertainty increase is larger for woody biomes than for herbaceous types.Contrastingly,the MODIS LAI product uncertainty remained stable over the study period.The uncertainty increase indicated by GEOV2 is partly attributed to the sensor shift in the product series.Further algorithm enhancement is necessary to improve the cross-sensor performance.This study highlights the importance of studying the LAI uncertainty and the uncertainty variation.Temporal variations in the LAI products and the product quality revealed herein have significant implications on global vegetation change studies.展开更多
Background Administrative data are frequently used in stroke research.Ensuring accurate identification of patients who had an ischaemic stroke,and those receiving thrombolysis and endovascular thrombectomy(EVT)is crit...Background Administrative data are frequently used in stroke research.Ensuring accurate identification of patients who had an ischaemic stroke,and those receiving thrombolysis and endovascular thrombectomy(EVT)is critical to ensure representativeness and generalisability.We examined differences in patient samples based on mode of identification,and propose a strategy for future patient and procedure identification in large administrative databases.Methods We used non-public administrative data from the state of California to identify all patients who had an ischaemic stroke discharged from an emergency department(ED)or inpatient hospitalisation from 2010 to 2017 based on International Classification of Disease(ICD-9)(2010-2015),ICD-10(2015-2017)and Medicare Severity-Diagnosis-related Group(MS-DRG)discharge codes.We identified patients with interhospital transfers,patients receiving thrombolytics and patients treated with EVT based on ICD,Current Procedural Terminology(CPT)and MS-DRG codes.We determined what proportion of these transfers and procedures would have been identified with ICD versus MS-DRG discharge codes.Results Of 365099 ischaemic stroke encounters,most(87.70%)had both a stroke-related ICD-9 or ICD-10 code and stroke-related MS-DRG code;12.28% had only an ICD-9 or ICD-10 code and 0.02% had only an MS-DRG code.Nearly all transfers(99.99%)were identified using ICD codes.We identified 32433 thrombolytic-treated patients(8.9% of total)using ICD,CPT and MS-DRG codes;the combination of ICD and CPT codes identified nearly all(98%).We identified 7691 patients treated with EVT(2.1%of total)using ICD and MS-DRG codes;both MS-DRG and ICD-9/ICD-10 codes were necessary because ICD codes alone missed 13.2%of EVTs.CPT codes only pertain to outpatient/ED patients and are not useful for EVT identification.Conclusions ICD-9/ICD-10 diagnosis codes capture nearly all ischaemic stroke encounters and transfers,while the combination of ICD-9/ICD-10 and CPT codes are adequate for identifying thrombolytic treatment in administrative datasets.However,MS-DRG codes are necessary in addition to ICD codes for identifying EVT,likely due to favourable reimbursement for EVT-related MS-DRG codes incentivising accurate coding.展开更多
ZnO-CeO2/SBA-15 catalysts were prepared by two kinds of solid-state grinding method and used for the production of 1,3-butadiene(1,3-BD) from ethanol.A mixture of SBA-15(with or without organic template) and metal pre...ZnO-CeO2/SBA-15 catalysts were prepared by two kinds of solid-state grinding method and used for the production of 1,3-butadiene(1,3-BD) from ethanol.A mixture of SBA-15(with or without organic template) and metal precursors were ground in solid-state.The obtained catalysts were characterized by TG,N2 adsorption-desorption,TEM,XRD,Py-FTIR and NH_3-TPD techniques.Superior dispersion of metal oxides and more exposed acid sites were achieved on the catalyst lOZn_1Ce_5-AS with the presence of organic template in SBA-15 during the solid-state grinding process.The catalytic performance was evaluated in a fixed-bed reactor and a 1,3-butadiene selectivity of as high as 45% is achieved.This is attributed to the coupling effect of Zn and Ce species in the mesopores of SBA-15,in which Zn promotes ethanol dehydrogenation and Ce enhances aldol-condensation,respectively.Additionally,solvent-free method inspires new catalyst synthesis strategy for the production of 1,3-butadiene from ethanol.展开更多
The geothermal resources in the southwest section of the Mid-Spine Belt of Beautiful China are abundant,but the quantitative prediction and evaluation of geothermal resources are very difficult. Based on geographic in...The geothermal resources in the southwest section of the Mid-Spine Belt of Beautiful China are abundant,but the quantitative prediction and evaluation of geothermal resources are very difficult. Based on geographic information system (GIS) and remote sensing (RS) platforms,six impact factors,namely land surface temperature,fault density,Gutenberg–Liszt B value,formation combination entropy,distance to river and aeromagnetic anomaly were selected. Through the establishment of the certainty factor model (CF),weights of the information entropy certainty factor model (ICF) and weights of the evidence certainty factor model (ECF),the geothermal potential in the study area were predicted quantitatively. Based on the ECF results,the six main geothermal resource areas were delineated. The results show that (1) ECF had high prediction accuracy (success index is 0.00405%,area ratio is 0.867);(2) The geothermal resource areas obtained were Ganzi–Ya’an–Liangshan,Panzhihua–Liangshan,Dali–Chuxiong,Nujiang–Baoshan,Diqing–Dali,and Lijiang–Diqing. The results provide a basis for the effective development and utilization of geothermal resources in the southwest section of the mid-ridge belt.展开更多
Unfolded protein response(UPR) is a stress response that is specific to the endoplasmic reticulum(ER).UPR is activated upon accumulation of unfolded(or misfolded) proteins in the ER's lumen to restore protein fold...Unfolded protein response(UPR) is a stress response that is specific to the endoplasmic reticulum(ER).UPR is activated upon accumulation of unfolded(or misfolded) proteins in the ER's lumen to restore protein folding capacity by increasing the synthesis of chaperones.In addition,UPR also enhances degradation of unfolded proteins and reduces global protein synthesis to alleviate additional accumulation of unfolded proteins in the ER.Herein,we describe a cell-based ultra-high throughput screening(uHTS) campaign that identifies a small molecule that can modulate UPR and ER stress in cellular and in vivo disease models.Using asialoglycoprotein receptor 1(ASGR) fused with Cypridina luciferase(CLuc) as reporter assay for folding capacity,we have screened a million small molecule library and identified APC655 as a potent activator of protein folding,that appears to act by promoting chaperone expression.Furthermore,APC655 improved pancreatic β cell viability and insulin secretion under ER stress conditions induced by thapsigargin or cytokines.APC655 was also effective in preserving β cell function and decreasing lipid accumulation in the liver of the leptin-deficient(ob/ob) mouse model.These results demonstrate a successful uHTS campaign that identified a modulator of UPR,which can provide a novel candidate for potential therapeutic development for a host of metabolic diseases.展开更多
文摘Myocardial infarction (MI), the most serious of the ischemic heart diseases, is accompanied by myocardial metabolic disorders and the loss of cardiomyocytes. Increasing evidence has shown that long noncoding RNAs (lncRNAs) are involved in various pathological conditions such as cancer and cardiovascular diseases (CVDs), and are emerging as a novel biomarker for these disorders. This study aims to investigate the regulatory role and mechanisms of lncRNAs in myocardial remodeling in the setting of MI. We find that post-infarcted hearts exhibit a reduction of adenosine triphosphate (ATP) and an alteration of the glucose and lipid metabolism genes cluster of differentiation 36 (CD36), hexokinase 1 (HK1), and clucose transporter 4 (GLUT4), accompanied by cardiomyocyte pyroptosis. We then identify a previously unknown conserved lncRNA, AK009126 (cardiomyocyte pyroptosis-associated lncRNA, CPAL), which is remarkably upregulated in the myocardial border zone of MI mice. Importantly, the adeno-associated virus 9 (AAV9)-mediated silencing of endogenous CPAL by its short hairpin RNA (shRNA) partially abrogates myocardial metabolic alterations and cardiomyocyte pyroptosis during MI in mice. Mechanistically, CPAL is shown to bind directly to nuclear factor kappa B (NFκB) and to act as an activator of NFκB to induce NFκB phosphorylation in cardiomyocytes. We also find that CPAL upregulates caspase-1 expression at the transcriptional level and consequently promotes the release of interleukin (IL)-18 and IL-1β from cardiomyocytes. Collectively, our findings reveal the conserved lncRNA CPAL as a new regulator of cardiac metabolic abnormalities and cardiomyocyte pyroptosis in the setting of MI and suggest CPAL as a new therapeutic target to protect cardiomyocytes against ischemic injury in infarcted hearts.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2009CB219504-03)the National Natural Science Foundation of China (Grant No 51106054)the Colleges and Universities High-level Talents Program of Guangdong
文摘In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.
基金supported by the National Basic Research (973) Program of China (Grant No. 2013CB430106)the R&D Special Fund for Public Welfare Industry (Meteorology) (Grant Nos. GYHY201306002 and GYHY201206005)+2 种基金the National Natural Science Foundation of China (Grant Nos. 40830958 and 41175087)the Jiangsu Collaborative Innovation Center for Climate Changethe High Performance Computing Center of Nanjing University
文摘Ensemble forecasting has become the prevailing method in current operational weather forecasting. Although ensemble mean forecast skill has been studied for many ensemble prediction systems(EPSs) and different cases, theoretical analysis regarding ensemble mean forecast skill has rarely been investigated, especially quantitative analysis without any assumptions of ensemble members. This paper investigates fundamental questions about the ensemble mean, such as the advantage of the ensemble mean over individual members, the potential skill of the ensemble mean, and the skill gain of the ensemble mean with increasing ensemble size. The average error coefficient between each pair of ensemble members is the most important factor in ensemble mean forecast skill, which determines the mean-square error of ensemble mean forecasts and the skill gain with increasing ensemble size. More members are useful if the errors of the members have lower correlations with each other, and vice versa. The theoretical investigation in this study is verified by application with the T213 EPS. A typical EPS has an average error coefficient of between 0.5 and 0.8; the 15-member T213 EPS used here reaches a saturation degree of 95%(i.e., maximum 5% skill gain by adding new members with similar skill to the existing members) for 1–10-day lead time predictions, as far as the mean-square error is concerned.
基金National Natural Science Foundation of China for financial support(21878227)。
文摘A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Zn O serves as the active sites for the dehydrogenation of ethanol,and CeO_(2) promotes the aldolcondensation reaction.Based on the results of Py-FTIR and NH_(3)-TPD,it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface,given their benefit for aldol-condensation reactions.The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid.Coupling with the Zn O sites,it contributes to a 98.4%conversion of ethanol and a 45.2%selective of 1,3-butadiene under relatively mild reaction conditions(375°C,101.325 k Pa,and 0.54 h^(-1)).
基金supported by Nonprofit Research Projects(CAFYBB2021QD001)of Chinese Academy of ForestryNational Key R&D Program of China(2019YFD1001602)。
文摘Fruit lignification is of significant economic importance because it affects the quality of fruit and the production of seed oil.The specified lignification pattern in Camellia chekiangoleosa fruits plays critical roles in its seed oil yield,but little is known about how this lignification process is regulated.Here,we report on a comprehensive tissue-specific transcriptomics analysis conducted for C.chekiangoleosa fruit.By mining the differentially expressed genes,we found that lignin biosynthesis and transcriptional regulation pathways were significantly enriched in the lignified tissues.The homolog of NST-like transcription factor,CcNST1,was highly expressed in lignified seed coat and endocarp tissues;transgenic analyses of CcNST1 in Arabidopsis and hybrid poplar revealed the enhanced lignification levels of various tissues.Gene expression analysis of the transgenic lines uncovered potential downstream genes involved in the regulation of lignin biosynthesis.This work provides a valuable gene expression resource and identified the pivotal role of CcNST1 in regulating the lignin biosynthesis underlying fruit lignification.
基金the National Natural Science Foundation of China[81573434 to BZC]Heilongjiang Touyan Innovation Team Program[BZC],HMU Marshal Initiative Funding(HMUMIF-21018 to BZC)National Nature Science Youth Foudation of China[82000226 to XFG].
文摘Background:Cardiomyocytes derived from human embryonic stem cells(hESCs)are regulated by complex and stringent gene networks during differentiation.Long non-coding RNAs(lncRNAs)exert critical epigenetic regulatory functions in multiple differentiation processes.However,the involvement of lncRNAs in the differentiation of hESCs into cardiomyocytes has not yet been fully elucidated.Here,we identified the key roles of ZFAS1(lncRNA zinc finger antisense 1)in the differentiation of cardiomyocytes from hESCs.Methods:A model of cardiomyocyte differentiation from stem cells was established using the monolayer differentiation method,and the number of beating hESCs-derived cardiomyocytes was calculated.Gene expression was analyzed by quantitative real-time PCR(qRTPCR).Immunofluorescence assays were performed to assess the expression of cardiac troponin T(cTnT)andα-actinin protein in cardiomyocytes.Results:qRT-PCR showed that ZFAS1 expression in the mesoderm was significantly higher than that in embryonic stem cells,cardiac progenitor cells,and cardiomyocytes.Knockdown of ZFAS1 inhibited cardiomyocyte differentiation from hESCs,which was characterized by reduced expression of the cardiac-specific markers cTnT,α-actinin,myosin heavy chain 6(MYH6),and myosin heavy chain 7(MYH7).In contrast,ZFAS1 overexpression remarkably increased the percentage of spontaneously beating cardiomyocytes.In terms of the mechanism,we found that ZFAS1 is an antisense lncRNA at the 5′end of the protein-coding gene ZNFX1.Knockdown of ZFAS1 could increase the mRNA expression level of ZNFX1.Furthermore,qRT-PCR demonstrated that the silencing of ZNFX1 led to an increase in cardiac-specific markers that predicted the promotion of cardiomyocyte differentiation.Conclusion:Altogether,these data suggest that lncRNA-ZFAS1 is required for cardiac differentiation by functionally inhibiting the expression of ZNFX1,which may provide a reference for the treatment of heart disease to a certain extent.
基金supported by the National Natural Science Foundation of China(21871079,21501052)the Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(YQ2019B006)~~
文摘Duckweed is a group of aquatic plants with the potential of wastewater remediation and fast accumulation of biomass. The accumulated biomass, rich in cellulose, starch and protein, can be used for biofuel, bio-fertilizer, animal feed and human food. Characterization of natural biodiversity of duckweed species is essential for the germplasm preservation and various practical applications. We have collected samples of duckweed in eastern China and characterized species biodiversity by genotyping, using chloroplast (atpF-atpH and psbK-psbI spacers). Spirodela polyrhiza was revealed as a clear dominant duckweed species in all locations of the area. Other duckweed species were identified as Landoltia punctata, Lemna aequinoctialis and Lemna turionifera. Selected isolates of these four species were used in the experiments to estimate their potential in removing nitrogen and phosphorus nutrients from municipal and industrial wastewater sampled at the local sewage plants. Duckweed was able to reduce the concentration of nitrogen up to 98% and phosphorus up to 96%. The presented data demonstrates high efficiency of the local duckweed isolates for bioremediation of different types of wastewater and the great potential of duckweed for wastewater treatment when incorporated into the purification chain.
基金supported by the National Natural Science Foundation of China(No.51874115)the CAS Youth Innovation Promotion Association(No.2019190)+2 种基金the Postdoctoral Science Foundation funded project of China(No.2020T130166)the Major Projects of the Natural Science Foundation of Gansu Province,China(No.18JR4RA001)the Excellent Young Scientist Foundation of Hebei Province,China(No.E2018202241).
文摘In this work,highly dispersed atomically-thin MoS2 nanosheets were fabricated at one thousandth of the commercial cost using sepiolite(SEP)mineral nanofibers as carriers via a microwave hydrothermal method.Atomresolved microscopy revealed the MoS2 nanosheets were only 1–4 atomic layers thick.The Mo atoms anchored on the mineral surface served as nucleation sites for the nanosheet growth.The MoS2 layers were in staggered stacking yielding abundant atomic steps at the nanosheets’edges,where catalytically active molybdenum terminations dominated instead of the inert sulfur atoms commonly reported.DFT calculations disclosed that the bonding of Mo(MoS2)and O(SEP)at the MoS2/sepiolite(MSEP)interface enabled SEP to be a unique support,superior to the other minerals for growing such highly-dispersed ultrathin MoS2 architecture.In a typical photocatalyisis application,the MSEP demonstrated a significantly improved photocatalytic performance for RhB degradation compared with the MoS2 nanosheets assembled microspheres.This work provides an important new strategy for low-cost batch preparation of high quality 2D materials via assembly on mineral materials.
基金The research was jointly supported by the National Key Research and Development Project of China(2021YFB3901101)the National Natural Science Foundation of China(42171374,42071336,42001311,42101366)+3 种基金the Natural Science Foundation of Jilin Province,China(20220203024SF)Youth Innovation Promotion Association of Chinese Academy of Sciences,China(2020234)Young Scientist Group Project of Northeast Institute of Geography and Agroecology,China(2023QNXZ01)Chinese Academy of Sciences and Postdoctoral Fellowship of Jilin Province of China to Yingxin Shang.
文摘Suspended particulate matter(SPM)in lakes exerts strong impact on light propagation,aquatic ecosystem productivity,which co-varies with nutrients,heavy metal and micro-pollutant in waters.In lakes,SPM exerts strong absorption and backscattering,ultimately affects water leaving signals that can be detected by satellite sensors.Simple regression models based on specific band or hand ratios have been widely used for SPM estimate in the past with moderate accuracy.There are still rooms for model accuracy improvements,and machine learning models may solve the non-linear relationships between spectral variable and SPM in waters.We assembled more than 16,400 in situ measured SPM in lakes from six continents(excluding the Antarctica continent),of which 9640 samples were matched with Landsat overpasses within±7 days.Seven machine learning algorithms and two simple regression methods(linear and partial least squares models)were used to estimate SPM in lakes and the performance were compared.To overcome the problem of imbalance datasets in regression,a Synthetic Minority Over-Sampling technique for regression with Gaussian Noise(SMOGN)was adopted in this study.Through comparison,we found that gradient boosting decision tree(GBDT),random forest(RF),and extreme gradient boosting(XGBoost)models demonstrated good spatiotemporal transferability with SMOGN processed dataset,and has potential to map SPM at different year with good quality of Landsat land surface reflectance images.In all the tested modeling approaches,the GBDT model has accurate calibration(n=6428,R^(2)=0.95,MAPE=29.8%)from SPM collected in 2235 lakes across the world,and the validation(n=3214,R^(2)=0.84,MAPE=38.8%)also exhibited stable performance.Further,the good performances were also exhibited by RF model with calibration(R^(2)=0.93)and validation(R^(2)=0.86,MAPE=24.2%)datasets.We applied GBDT and RF models to map SPM of typical lakes,and satisfactory result was obtained.In addition,the GBDT model was evaluated by historical SPM measurements coincident with different Landsat sensors(L5-TM,L7-ETM+,and L8-OLI),thus the model has the potential to map SPM of lakes for monitoring temporal variations,and tracks lake water SPM dynamics in approximately the past four decades(1984-2021)since Landsat-5/TM was launched in 1984.
基金National Natural Science Foundation of China(62171460)Natural Science Basic Research Program of Shaanxi Province(2022JM-319,2022JQ-685,20210110,20200108,20220104,2020022)。
文摘An ultrawideband,polarization-insensitive,metamaterial absorber for oblique angle of incidence is presented using characteristic mode analysis.The absorber consists of conductive meander square loops and symmetric bent metallic strips,which are embedded with lumped resistors.With the aid of modal currents and modal weighting coefficients,the positions of the lumped resistors are determined.After that,the equivalent circuit(EC)model and admittance formula are proposed and analyzed to further understand the working principle and ultrawide bandwidth.The proposed absorber measures an absorption bandwidth of 4.3–26.5 GHz(144.1%in fractional bandwidth)for 90%absorptivity under normal incidence.At the oblique angle of incidence of 45°,the bandwidth of 90%absorptivity is still 5.1–21.3 GHz(122.72%)for transverse electric(TE)polarization,and 6.8–29.5 GHz(125.07%)for transverse magnetic(TM)polarization.The good agreement among simulation,measurement,and EC calculation demonstrates the validity of the proposed method and indicates that the method can be applied to other microwave and optical frequency bands.The proposed metamaterial absorber can be widely applied in electromagnetic compatibility,electromagnetic interference,radar stealth,and biomedical detection.
基金supported by the National Key Research and Development Program of China(2016YFA0600201)。
文摘Leaf area index(LAI)is an essential climate variable that is crucial to understand the global vegetation change.Long-term satellite LAI products have been applied in many global vegetation change studies.However,these LAI products contain various uncertainties that are not been fully considered in current studies.The objective of this study is to explore the uncertainties in the global LAI products and the uncertainty variations.Two global LAI datasets—the European Geoland2 Version 2(GEOV2)and Moderate Resolution Imaging Spectroradiometer(MODIS)(2003-2019)—were investigated.The qualitative quality flags(QQFs)and quantitative quality indicators(QQIs)embedded in the product quality layers were analyzed to identify the temporal anomalies in the quality profile.The results show that the global GEOV2(0.042/10a)and MODIS(0.034/10a)LAI values have steadly increased from 2003 to 2019.The global LAI uncertainty(0.016/10a)and relative uncertainty(0.3%/10a)from GEOV2 have also increased gradually,especially during the growing season from April to October.The uncertainty increase is larger for woody biomes than for herbaceous types.Contrastingly,the MODIS LAI product uncertainty remained stable over the study period.The uncertainty increase indicated by GEOV2 is partly attributed to the sensor shift in the product series.Further algorithm enhancement is necessary to improve the cross-sensor performance.This study highlights the importance of studying the LAI uncertainty and the uncertainty variation.Temporal variations in the LAI products and the product quality revealed herein have significant implications on global vegetation change studies.
基金Agency for Healthcare Research and Quality(PI Zachrison,K08HS024561)National Institutes of Health(PI Hsia R01HL134182,R01HL114822).
文摘Background Administrative data are frequently used in stroke research.Ensuring accurate identification of patients who had an ischaemic stroke,and those receiving thrombolysis and endovascular thrombectomy(EVT)is critical to ensure representativeness and generalisability.We examined differences in patient samples based on mode of identification,and propose a strategy for future patient and procedure identification in large administrative databases.Methods We used non-public administrative data from the state of California to identify all patients who had an ischaemic stroke discharged from an emergency department(ED)or inpatient hospitalisation from 2010 to 2017 based on International Classification of Disease(ICD-9)(2010-2015),ICD-10(2015-2017)and Medicare Severity-Diagnosis-related Group(MS-DRG)discharge codes.We identified patients with interhospital transfers,patients receiving thrombolytics and patients treated with EVT based on ICD,Current Procedural Terminology(CPT)and MS-DRG codes.We determined what proportion of these transfers and procedures would have been identified with ICD versus MS-DRG discharge codes.Results Of 365099 ischaemic stroke encounters,most(87.70%)had both a stroke-related ICD-9 or ICD-10 code and stroke-related MS-DRG code;12.28% had only an ICD-9 or ICD-10 code and 0.02% had only an MS-DRG code.Nearly all transfers(99.99%)were identified using ICD codes.We identified 32433 thrombolytic-treated patients(8.9% of total)using ICD,CPT and MS-DRG codes;the combination of ICD and CPT codes identified nearly all(98%).We identified 7691 patients treated with EVT(2.1%of total)using ICD and MS-DRG codes;both MS-DRG and ICD-9/ICD-10 codes were necessary because ICD codes alone missed 13.2%of EVTs.CPT codes only pertain to outpatient/ED patients and are not useful for EVT identification.Conclusions ICD-9/ICD-10 diagnosis codes capture nearly all ischaemic stroke encounters and transfers,while the combination of ICD-9/ICD-10 and CPT codes are adequate for identifying thrombolytic treatment in administrative datasets.However,MS-DRG codes are necessary in addition to ICD codes for identifying EVT,likely due to favourable reimbursement for EVT-related MS-DRG codes incentivising accurate coding.
基金financial support from the National Natural Science Foundation of China(No.21878227)。
文摘ZnO-CeO2/SBA-15 catalysts were prepared by two kinds of solid-state grinding method and used for the production of 1,3-butadiene(1,3-BD) from ethanol.A mixture of SBA-15(with or without organic template) and metal precursors were ground in solid-state.The obtained catalysts were characterized by TG,N2 adsorption-desorption,TEM,XRD,Py-FTIR and NH_3-TPD techniques.Superior dispersion of metal oxides and more exposed acid sites were achieved on the catalyst lOZn_1Ce_5-AS with the presence of organic template in SBA-15 during the solid-state grinding process.The catalytic performance was evaluated in a fixed-bed reactor and a 1,3-butadiene selectivity of as high as 45% is achieved.This is attributed to the coupling effect of Zn and Ce species in the mesopores of SBA-15,in which Zn promotes ethanol dehydrogenation and Ce enhances aldol-condensation,respectively.Additionally,solvent-free method inspires new catalyst synthesis strategy for the production of 1,3-butadiene from ethanol.
基金funded by National Key Research and Development Program of China (2017YFC0601500,2017YFC0601502)Strategic Priority Research Program of the Chinese Academy of Sciences (grant number XDA19090121)+1 种基金National Natural Science Foundation of China (42002298)Key Research and Development Program of Sichuan Provincial Science and Technology Department (2022YFS0486).
文摘The geothermal resources in the southwest section of the Mid-Spine Belt of Beautiful China are abundant,but the quantitative prediction and evaluation of geothermal resources are very difficult. Based on geographic information system (GIS) and remote sensing (RS) platforms,six impact factors,namely land surface temperature,fault density,Gutenberg–Liszt B value,formation combination entropy,distance to river and aeromagnetic anomaly were selected. Through the establishment of the certainty factor model (CF),weights of the information entropy certainty factor model (ICF) and weights of the evidence certainty factor model (ECF),the geothermal potential in the study area were predicted quantitatively. Based on the ECF results,the six main geothermal resource areas were delineated. The results show that (1) ECF had high prediction accuracy (success index is 0.00405%,area ratio is 0.867);(2) The geothermal resource areas obtained were Ganzi–Ya’an–Liangshan,Panzhihua–Liangshan,Dali–Chuxiong,Nujiang–Baoshan,Diqing–Dali,and Lijiang–Diqing. The results provide a basis for the effective development and utilization of geothermal resources in the southwest section of the mid-ridge belt.
基金supported by the Juvenile Diabetes Research Foundation (JDRF) [3-PAR-2016-241-I-X, US]。
文摘Unfolded protein response(UPR) is a stress response that is specific to the endoplasmic reticulum(ER).UPR is activated upon accumulation of unfolded(or misfolded) proteins in the ER's lumen to restore protein folding capacity by increasing the synthesis of chaperones.In addition,UPR also enhances degradation of unfolded proteins and reduces global protein synthesis to alleviate additional accumulation of unfolded proteins in the ER.Herein,we describe a cell-based ultra-high throughput screening(uHTS) campaign that identifies a small molecule that can modulate UPR and ER stress in cellular and in vivo disease models.Using asialoglycoprotein receptor 1(ASGR) fused with Cypridina luciferase(CLuc) as reporter assay for folding capacity,we have screened a million small molecule library and identified APC655 as a potent activator of protein folding,that appears to act by promoting chaperone expression.Furthermore,APC655 improved pancreatic β cell viability and insulin secretion under ER stress conditions induced by thapsigargin or cytokines.APC655 was also effective in preserving β cell function and decreasing lipid accumulation in the liver of the leptin-deficient(ob/ob) mouse model.These results demonstrate a successful uHTS campaign that identified a modulator of UPR,which can provide a novel candidate for potential therapeutic development for a host of metabolic diseases.