Achieving high maize yields and efficient phosphorus(P)use with limited environmental impacts is one of the greatest challenges in sustainable maize production.Increasing plant density is considered an effective appro...Achieving high maize yields and efficient phosphorus(P)use with limited environmental impacts is one of the greatest challenges in sustainable maize production.Increasing plant density is considered an effective approach for achieving high maize yields.However,the low mobility of P in soils and the scarcity of natural P resources have hindered the development of methods that can simultaneously optimize P use and mitigate the P-related environmental footprint at high plant densities.In this study,meta-analysis and substance flow analysis were conducted to evaluate the effects of different types of mineral P fertilizer on maize yield at varying plant densities and assess the flow of P from rock phosphate mining to P fertilizer use for maize production in China.A significantly higher yield was obtained at higher plant densities than at lower plant densities.The application of single superphosphate,triple super-phosphate,and calcium magnesium phosphate at high plant densities resulted in higher yields and a smaller environmental footprint than the application of diammonium phosphate and monoammonium phosphate.Our scenario analyses suggest that combining the optimal P type and application rate with a high plant density could increase maize yield by 22%.Further,the P resource use efficiency throughout the P supply chain increased by 39%,whereas the P-related environmental footprint decreased by 33%.Thus,simultaneously optimizing the P type and application rate at high plant densities achieved multiple objectives during maize production,indicating that combining P management with cropping techniques is a practical approach to sustainable maize production.These findings offer strategic,synergistic options for achieving sustainable agricultural development.展开更多
Gearbox is a key part in machinery,in which gear,shaft and bearing operate together to transmit motion and power.The wide usage and high failure rate of gearbox make it attract much attention on its health monitoring ...Gearbox is a key part in machinery,in which gear,shaft and bearing operate together to transmit motion and power.The wide usage and high failure rate of gearbox make it attract much attention on its health monitoring and fault diagnosis.Dynamic modelling can study the mechanism under different faults and provide theoretical foundation for fault detection.However,current commonly used gear dynamic model usually neglects the influence of bearing and shaft,resulting in incomplete understanding of gearbox fault diagnosis especially under the effect of local defects on gear and shaft.To address this problem,an improved gear-shaft-bearing-housing dynamic model is proposed to reveal the vibration mechanism and responses considering shaft whirling and gear local defects.Firstly,an eighteen degree-of-freedom gearbox dynamic model is proposed,taking into account the interaction among gear,bearing and shaft.Secondly,the dynamic model is iteratively solved.Then,vibration responses are expounded and analysed considering gear spalling and shaft crack.Numerical results show that the gear mesh frequency and its harmonics have higher amplitude through the spectrum.Vibration RMS and the shaft rotating frequency increase with the spalling size and shaft crack angle in general.An experiment is designed to verify the rationality of the proposed gearbox model.Lastly,comprehensive analysis under different spalling size and shaft crack angle are analysed.Results show that when spalling size and crack angle are larger,RMS and the amplitude of shaft rotating frequency will not increase linearly.The dynamic model can accurately simulate the vibration of gear transmission system,which is helpful for gearbox fault diagnosis.展开更多
The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediment...The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediments in the northern ECS shelf are distributed in a ring-shaped distribution centered on the southwestern Cheju Island Mud.From the inside to the outside,the grain size goes from fine to coarse.Aside from the“grain size effect”,hydrodynamic sorting and mineral composition are important restrictions on the content of rare earth elements(REEs).Based on the grain size,REEs,and clay mineral composition of 300 surface sediments,as well as the sedimentary genesis,the northern ECS shelf is divided into three geochemical zones:southwestern Cheju Island Mud Area(ZoneⅠ),Changjiang Shoal Sand Ridges(ZoneⅡ-1),Sand Ridges of the East China Sea shelf(ZoneⅡ-2).The northern ECS shelf is mostly impacted by Chinese mainland rivers(the Changjiang River and Huanghe River),and the provenance and transport mechanism of sediments of different grain sizes is diverse.The bulk sediments come primarily from the Changjiang River,with some material from the Huanghe River carried by the Yellow Sea Coastal Current and the North Jiangsu Coastal Current,and less from Korean rivers.Among them,surface sediments in the southwestern Cheju Island Mud Area(ZoneⅠ)come mostly from the Changjiang River and partly from the Huanghe River.It was formed by the counterclockwise rotating cold eddies in the northern ECS shelf,which caused the sedimentation and accumulation of the fine-grained sediments of the Changjiang River and the Huanghe River.The Changjiang Shoal Sand Ridges(ZoneⅡ-1)were developed during the early-middle Holocene sea-level highstand.It is the modern tidal sand ridge sediment formed by intense hydrodynamic action under the influence of the Yellow Sea Coastal Current,North Jiangsu Coastal Current,and Changjiang Diluted Water.The surface sediments mainly originate from the Changjiang River and Huanghe River,with the Changjiang River dominating,and the Korean River(Hanjiang River)influencing just a few stations.Sand Ridges of the East China Sea shelf(ZoneⅡ-2)are the relict sediments of the paleo-Changjiang River created by sea invasion at the end of the Last Deglaciation in the Epipleistocene.The clay mineral composition of the surface sediments in the study area is just dominated by the Changjiang River,with the North Jiangsu Coastal Current and the Changjiang Diluted Water as the main transporting currents.展开更多
Knowledge graph(KG)fact prediction aims to complete a KG by determining the truthfulness of predicted triples.Reinforcement learning(RL)-based approaches have been widely used for fact prediction.However,the existing ...Knowledge graph(KG)fact prediction aims to complete a KG by determining the truthfulness of predicted triples.Reinforcement learning(RL)-based approaches have been widely used for fact prediction.However,the existing approaches largely suffer from unreliable calculations on rule confidences owing to a limited number of obtained reasoning paths,thereby resulting in unreliable decisions on prediction triples.Hence,we propose a new RL-based approach named EvoPath in this study.EvoPath features a new reward mechanism based on entity heterogeneity,facilitating an agent to obtain effective reasoning paths during random walks.EvoPath also incorporates a new postwalking mechanism to leverage easily overlooked but valuable reasoning paths during RL.Both mechanisms provide sufficient reasoning paths to facilitate the reliable calculations of rule confidences,enabling EvoPath to make precise judgments about the truthfulness of prediction triples.Experiments demonstrate that EvoPath can achieve more accurate fact predictions than existing approaches.展开更多
Saturated fractions in a total of 23 oil samples and hydrocarbon source rocks from the Songliao, Tarim,and Ordos Basins have been analyzed by GC–MS and GC–MS–MS. According to the relative retention, mass spectral c...Saturated fractions in a total of 23 oil samples and hydrocarbon source rocks from the Songliao, Tarim,and Ordos Basins have been analyzed by GC–MS and GC–MS–MS. According to the relative retention, mass spectral characteristics, and comparison with existing literature, a complete carbon number distribution ranging from C27 to C35(without C28) in the 17a(H)-diahopane series and early-eluting rearranged hopane series is identified. Compounds in the 18a(H)-neohopane series(Ts and C29Ts) and21-methyl-28-nor-hopane series(29Nsp and 30Nsp) are also noted. These four series of rearranged hopanes seem to occur in both brackish-saline lacustrine and coal measure environments. However, the coal measure and swamp environments being under an oxic condition, compared with brackish-saline lacustrines, are presumably more helpful to the formation of 30 E. Diversity in the content and distribution patterns indicate that rearranged hopanes could serve as good indicators of organic facies, depositional environment and maturity in petroleum geology.展开更多
A simple and high throughput method was developed and validated for simultaneous determination of valproic acid and its two toxicant ene-metabolites, 2-enevalproic acid and 4-enevalproic acid in epilepsy patient plasm...A simple and high throughput method was developed and validated for simultaneous determination of valproic acid and its two toxicant ene-metabolites, 2-enevalproic acid and 4-enevalproic acid in epilepsy patient plasma using liquid chromatography-tandem mass spectrometry. Probenecid was used as in- ternal standard and solid-phase extraction was selected for sample preparation. A chromatographic separation was performed on an Agilent Poroshell SB-C18 column (50 mm × 4.6 mm i.d., 2.7μm) by an optimized gradient elution at a flow rate of 0.9 mL/min. The total run time was 7 rain. Electrospray ionization was used in negative ion mode by multiple reaction monitoring of the precursor-to-product ion transitions at m/z 143.0→143.0 for valproic acid, m/z 140.9 →140.9 for 2-enevalproic acid and 4-enevalproic acid for their poor fragments, and m/z 283.9→239,9 for probenecid. The results showed good linearity ofvalproic acid, 2-enevalproic acid and 4-enevalproic acid in their respective linear ranges. The correlation coefficients were more than 0.998, The intra- and inter-day precision of the assay was less than 11.0% and the accuracy ranged from 2% to 12%. This analytical method was successfully applied to assay plasma concentrations of valproic acid and its two ene-metabolites in epilepsy patient plasma and used for therapeutic drug monitoring.展开更多
A novel study using LCeMS(Liquid chromatography tandem mass spectrometry)coupled with multivariate data analysis and bioactivity evaluation was established for discrimination of aqueous extract and vinegar extract of...A novel study using LCeMS(Liquid chromatography tandem mass spectrometry)coupled with multivariate data analysis and bioactivity evaluation was established for discrimination of aqueous extract and vinegar extract of Shixiao San.Batches of these two kinds of samples were subjected to analysis,and the datasets of sample codes,tR-m/z pairs and ion intensities were processed with principal component analysis(PCA).The result of score plot showed a clear classification of the aqueous and vinegar groups.And the chemical markers having great contributions to the differentiation were screened out on the loading plot.The identities of the chemical markers were performed by comparing the mass fragments and retention times with those of reference compounds and/or the known compounds published in the literatures.Based on the proposed strategy,quercetin-3-Oneohesperidoside,isorhamnetin-3-O-neohespeeridoside,kaempferol-3-O-neohesperidoside,isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-(2G-a-l-rhamnosyl)-rutinoside were explored as representative markers in distinguishing the vinegar extract from the aqueous extract.The anti-hyperlipidemic activities of two processed extracts of Shixiao San were examined on serum levels of lipids,lipoprotein and blood antioxidant enzymes in a rat hyperlipidemia model,and the vinegary extract,exerting strong lipid-lowering and antioxidative effects,was superior to the aqueous extract.Therefore,boiling with vinegary was predicted as the greatest processing procedure for anti-hyperlipidemic effect of Shixiao San.Furthermore,combining the changes in the metabolic profiling and bioactivity evaluation,the five representative markers may be related to the observed antihyperlipidemic effect.展开更多
A simple, rapid and sensitive method based on an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. Th...A simple, rapid and sensitive method based on an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C18 column (100 mm × 2.1 mm, 1.7μm; Waters, USA), with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate (70:30, v/v), at a flow rate of 0.2 mL/min for 2.5 rain. The analyte and clarithromyein (the internal standard) were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 - 223.0 for pimavanserin and m/z 748.5 - 589.5 for clarithromycin. Relative coefficient (r) for the calibration curve was more than 0.9980. The intra-day and inter-day precisions (relative standard deviation, RSD%) were less than 13.3% and 10.5%, respectively, and the accuracy (relative error, RE%) was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.展开更多
The present study was designed to investigate the influence of the pretreatment of piperazine ferulate on pharmacokinetic parameters of methotrexate in methotrexate-induced renal injury rats.A simple and efficient hig...The present study was designed to investigate the influence of the pretreatment of piperazine ferulate on pharmacokinetic parameters of methotrexate in methotrexate-induced renal injury rats.A simple and efficient high performance liquid chromatography coupled with mass spectrometry(HPLC-MS)method was developed to determine methotrexate in rat plasma.Methotrexate and syringic acid(internal standard)were extracted from rat plasma samples by protein precipitation with acetonitrile.The analysis was performed on a CAPCELL PAK C18column(150 mm×4.6 mm,5μm)with acetonitrile and 5 mmol/l ammonium acetate aqueous(10:90,v/v).The linear range was 5.0×10-2to 100.0μg/ml for methotrexate.Other parameters were all within the acceptance criteria.The validated method was successfully applied the pharmacokinetic study of methotrexate between two methotrexate treated groups(with and without the pretreatment of piperazine ferulate).Compared with the methotrexate treated alone group,the pharmacokinetic parameters in the methotrexate with the pretreatment of piperazine ferulate group showed significantly lower MRT(0-t),MRT(0-∞) and T1/2.Results suggested that methotrexate can be rapidly eliminated,cleared or metabolized in rat blood,which might be related to the pretreatment of piperazine ferulate.The method provided deeper insights into rational clinical use of methotrexate with the pretreatment of piperazine ferulate on cancer patients with renal dysfunction.展开更多
Strobilation is a well-organized metamorphosis process in scyphozoan jellyfi sh,through which the benthic polyp develops into the pelagic medusa.So far,knowledge on the molecular mechanisms behind the drastic morpholo...Strobilation is a well-organized metamorphosis process in scyphozoan jellyfi sh,through which the benthic polyp develops into the pelagic medusa.So far,knowledge on the molecular mechanisms behind the drastic morphological and physiological changes remains limited.In the present study,the metabolic profi les in polyp and strobila stages of jellyfi sh Rhopilema esculentum were examined using ultra-performance liquid chromatography coupled to a mass spectrometer.A total of 3071 metabolites with putative annotation were detected,of which 167 were identifi ed as diff erential metabolites between the polyp and strobila.Among the metabolites,31 signifi cantly decreased and 136 signifi cantly increased in abundance in the strobila.Thyroxin,one of the previously proposed strobilation inducer of Aurelia,was not detected in this study.The indole-containing compounds are known for triggering strobilation in Discomedusae.Two indole derivatives and an indole-isomer containing metabolite were detected among the most signifi cantly increased metabolites,which may be potential endogenous molecules for strobilation initiation.The membrane-associated phospholipids and the infl ammation and oxidative stress-related eicosanoids were found to have signifi cant changes.Although the functions of these metabolites in strobilation are not yet completely known,they provide some clues to the induction of the process of strobilation and metabolic responses that take place during strobilation.展开更多
The explosive growth of data volume in mobile networks makes fast online diagnose a pressing search problem. In this paper, an object-oriented detection framework with a two-step clustering, named as Hourglass Cluster...The explosive growth of data volume in mobile networks makes fast online diagnose a pressing search problem. In this paper, an object-oriented detection framework with a two-step clustering, named as Hourglass Clustering, is given. Where three object parameters are chosen as Synthetical Quality of Experience(SQo E) Key Quality Indicators(KQIs) to reflect accessibility, integrality, and maintainability of networks. Then, we choose represented Key Performance Indicators(r KPIs) as cause parameters with correlation analysis. For these two kinds of parameters, a hybrid algorithm combining the self-organizing map(SOM) and展开更多
Larotaxel, a new taxane compound prepared by partial synthesis from 10-deacetyl baccatin III, is active against tumors. In this research, a selective LC–MS method was developed and validated for the study of degradat...Larotaxel, a new taxane compound prepared by partial synthesis from 10-deacetyl baccatin III, is active against tumors. In this research, a selective LC–MS method was developed and validated for the study of degradation kinetics of larotaxel, which was carried out in aqueous solutions with different pH(1.5, 3.0, 5.0, 6.5, 7.4, 9.0, 10 and 11.0) and temperature(0, 25, 37 and 45 °C). The linear range was 0.5–25 μg/mL, the intra-and inter-day precisions were less than 7.0%, and accuracy ranged from 97.4–104.5% for each analyte. The observed rate obtained by measuring the remaining intact larotaxel was shown to follow first-order kinetics. The activation energies for degradation were 126.7 and 87.01 k J/mol at pH 1.5 and 11, respectively. Although larotaxel was stable in pH 5, 6.5 and 7.4 buffers at 37 °C for 24 h during our study, increasing or decreasing the pH of the solutions would decrease its stabilities. Moreover, three main degradation products in alkaline condition were separated by HPLC and identified by Q–TOF–MS. The three degradation products were confirmed as 10-deacetyl larotaxel, 7, 8-cyclopropyl baccatin Ⅲ and 10-deacetyl-7, 8-cyclopropyl baccatin Ⅲ.展开更多
Cancer is the leading cause of death all over the world.Among the chemotherapy drugs,taxanes play an important role in cancer treatment.6258-70 is a new semi-synthetic taxane which has a broad spectrum of antitumor ac...Cancer is the leading cause of death all over the world.Among the chemotherapy drugs,taxanes play an important role in cancer treatment.6258-70 is a new semi-synthetic taxane which has a broad spectrum of antitumor activity.A fast and reliable high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method was developed for quantification of 6258-70 in rat plasma and tissues in this paper.After extraction by liquid-liquid extraction method with methyl tert-butyl ether,the samples were separated on a Kinetex C_(18) column(50 mm × 2.1 mm,2.6 μm,Phenomenex,USA) within3 min.The method was fully validated with the matrix effect between 87.7%and 99.5%and the recovery ranging from 80.3%to 90.1%.The intra- and inter-day precisions were less than 9.5%and the accuracy ranged from-3.8%to 6.5%.The reliable method was successfully applied to the pharmacokinetics and tissue distribution studies of 6258-70 after intravenous administration in rats.The pharmacokinetic results indicated that the pharmacokinetic behavior of 6258-70 in rats was in accordance with linear features within tested dosage of 1 to 4 mg/kg,and there was no significant difference between the two genders.The tissue distribution study showed that 6258-70 had an effective penetration,spread widely and rapidly and could cross blood-brain barrier.The results of pharmacokinetics and tissue distribution may provide a guide for future study.展开更多
The orphan nuclear receptor Nur77 is a critical regulator of the survival and death of tumor cells.The pro-death effect of Nur77 can be regulated by its interaction with Bcl-2,resulting in conversion of Bcl-2 from a s...The orphan nuclear receptor Nur77 is a critical regulator of the survival and death of tumor cells.The pro-death effect of Nur77 can be regulated by its interaction with Bcl-2,resulting in conversion of Bcl-2 from a survival to killer.As Bcl-2 is overexpressed in various cancers preventing them from apoptosis and promoting their resistance to chemotherapy,targeting the apoptotic pathway of Nur77/Bcl-2 may lead to new cancer therapeutics.Here,we report our identification of XS561 as a novel Nur77 ligand that induces apoptosis of tumor cells by activating the Nur77/Bcl-2 pathway.In vitro and animal studies revealed an apoptotic effect of XS561 in a range of tumor cell lines including MDA-MB-231 triple-negative breast cancer(TNBC)and MCF-7/LCC2 tamoxifen-resistant breast cancer(TAMR)in a Nur77-dependent manner.Mechanistic studies showed XS561 potently induced the translocation of Nur77 from the nucleus to mitochondria,resulting in mitochondria-related apoptosis.Interestingly,XS561-induced accumulation of Nur77 at mitochondria was associated with XS561 induction of Nur77 phase separation and the formation of Nur77/Bcl-2 condensates.Together,our studies identify XS561 as a new activator of the Nur77/Bcl-2 apoptotic pathway and reveal a role of phase separation in mediating the apoptotic effect of Nur77 at mitochondria.展开更多
Owing to the atomically thin nature,two-dimensional(2D)oxide materials have been widely reported to exhibit exciting transport and dielectric properties,such as fine gate controllability and ultrahigh carrier mobility...Owing to the atomically thin nature,two-dimensional(2D)oxide materials have been widely reported to exhibit exciting transport and dielectric properties,such as fine gate controllability and ultrahigh carrier mobility,that outperform their bulk counterpart.However,unlike the successful synthesis of bulk oxide single crystals,reliable methods for synthesizing large-area single crystal of 2D oxide,that would suppress the negative influence from defective grain boundaries,remain unavailable,especially for nonlayered oxide.Herein,we report that the lattice symmetry between the substrate and cerium dioxide(CeO_(2))would allow for the aligned nucleation and epitaxial growth of CeO_(2)on sapphire substrates,enabling the wafer-sized growth of CeO_(2)single crystal.The careful tuning of the growth temperature and oxygen flow rate contributed to the harvesting of CeO_(2)wafer with reduced thickness and enhanced growth rates.The removal of grain boundaries improved the dielectric performance in terms of high dielectric strength(E_(bd)≈8.8 MV·cm^(-1)),suppressed leakage current,along with high dielectric constants(ε_(r)≈24).Our work demonstrates that with fine dielectric performance and ease of synthesizing wafer-sized single crystals,CeO_(2)can function as potential candidate as gate insulator for 2D-materials based nanoelectronics,and we believe the reported protocol of aligned nucleation can be extended to other 2D oxides.展开更多
Estimating the proportion of land-use types in different regions is essential to promote the organization of a compact city and reduce energy consumption.However,existing research in this area has a few limitations:(1...Estimating the proportion of land-use types in different regions is essential to promote the organization of a compact city and reduce energy consumption.However,existing research in this area has a few limitations:(1)lack of consideration of land-use distribution-related factors other than POIs;(2)inability to extract complex relations from heterogeneous information;and(3)overlooking the correlation between land-use types.To overcome these limitations,we propose a knowledge-based approach for estimating land-use distributions.We designed a knowledge graph to display POIs and other related heterogeneous data and then utilized a knowledge embedding model to directly obtain the region embedding vectors by learning the complex and implicit relations present in the knowledge graph.Region embedding vectors were mapped to land-use distributions using a label distribution learning method integrating the correlation between land-use types.To prove the reliability and validity of our approach,we conducted a case study in Jinhua,China.The results indicated that the proposed model outperformed other algorithms in all evaluation indices,thus illustrating the potential of this method to achieve higher accuracy land-use distribution estimates.展开更多
Ferroptosis,a novel form of programmed cell death,is characterized by iron-dependent lipid peroxidation and has been shown to be involved in multiple diseases,including cancer.Stimulating ferroptosis in cancer cells m...Ferroptosis,a novel form of programmed cell death,is characterized by iron-dependent lipid peroxidation and has been shown to be involved in multiple diseases,including cancer.Stimulating ferroptosis in cancer cells may be a potential strategy for cancer therapy.Therefore,ferroptosis-inducing drugs are attracting more attention for cancer treatment.Here,we showed that erianin,a natural product isolated from Dendrobium chrysotoxum Lindl,exerted its anticancer activity by inducing cell death and inhibiting cell migration in lung cancer cells.Subsequently,we demonstrated for the first time that erianin induced ferroptotic cell death in lung cancer cells,which was accompanied by ROS accumulation,lipid peroxidation,and GSH depletion.The ferroptosis inhibitors Fer-1 and Lip-1 but not Z-VAD-FMK,CQ,or necrostatin-1 rescued erianin-induced cell death,indicating that ferroptosis contributed to erianin-induced cell death.Furthermore,we demonstrated that Ca^(2+)/CaM signaling was a critical mediator of erianin-induced ferroptosis and that blockade of this signaling significantly rescued cell death induced by erianin treatment by suppressing ferroptosis.Taken together,our data suggest that the natural product erianin exerts its anticancer effects by inducing Ca^(2+)/CaMdependent ferroptosis and inhibiting cell migration,and erianin will hopefully serve as a prospective compound for lung cancer treatment.展开更多
基金supported by the National Natural Science Foundation of China(32301453 and 3272675)the China Postdoctoral Science Foundation(2023M730682)。
文摘Achieving high maize yields and efficient phosphorus(P)use with limited environmental impacts is one of the greatest challenges in sustainable maize production.Increasing plant density is considered an effective approach for achieving high maize yields.However,the low mobility of P in soils and the scarcity of natural P resources have hindered the development of methods that can simultaneously optimize P use and mitigate the P-related environmental footprint at high plant densities.In this study,meta-analysis and substance flow analysis were conducted to evaluate the effects of different types of mineral P fertilizer on maize yield at varying plant densities and assess the flow of P from rock phosphate mining to P fertilizer use for maize production in China.A significantly higher yield was obtained at higher plant densities than at lower plant densities.The application of single superphosphate,triple super-phosphate,and calcium magnesium phosphate at high plant densities resulted in higher yields and a smaller environmental footprint than the application of diammonium phosphate and monoammonium phosphate.Our scenario analyses suggest that combining the optimal P type and application rate with a high plant density could increase maize yield by 22%.Further,the P resource use efficiency throughout the P supply chain increased by 39%,whereas the P-related environmental footprint decreased by 33%.Thus,simultaneously optimizing the P type and application rate at high plant densities achieved multiple objectives during maize production,indicating that combining P management with cropping techniques is a practical approach to sustainable maize production.These findings offer strategic,synergistic options for achieving sustainable agricultural development.
基金supported by National Key R&D Program of China (No.2022YFB3303600)the Fundamental Research Funds for the Central Universities (No.2022CDJKYJH048).
文摘Gearbox is a key part in machinery,in which gear,shaft and bearing operate together to transmit motion and power.The wide usage and high failure rate of gearbox make it attract much attention on its health monitoring and fault diagnosis.Dynamic modelling can study the mechanism under different faults and provide theoretical foundation for fault detection.However,current commonly used gear dynamic model usually neglects the influence of bearing and shaft,resulting in incomplete understanding of gearbox fault diagnosis especially under the effect of local defects on gear and shaft.To address this problem,an improved gear-shaft-bearing-housing dynamic model is proposed to reveal the vibration mechanism and responses considering shaft whirling and gear local defects.Firstly,an eighteen degree-of-freedom gearbox dynamic model is proposed,taking into account the interaction among gear,bearing and shaft.Secondly,the dynamic model is iteratively solved.Then,vibration responses are expounded and analysed considering gear spalling and shaft crack.Numerical results show that the gear mesh frequency and its harmonics have higher amplitude through the spectrum.Vibration RMS and the shaft rotating frequency increase with the spalling size and shaft crack angle in general.An experiment is designed to verify the rationality of the proposed gearbox model.Lastly,comprehensive analysis under different spalling size and shaft crack angle are analysed.Results show that when spalling size and crack angle are larger,RMS and the amplitude of shaft rotating frequency will not increase linearly.The dynamic model can accurately simulate the vibration of gear transmission system,which is helpful for gearbox fault diagnosis.
基金The National Natural Science Foundation of China under contract Nos 42276084 and 42176078the Special survey items of the China Geological Survey under contract Nos DD20190205 and DD20221710。
文摘The composition,provenance,and genetic mechanism of sediment on different sedimentary units of the East China Sea(ECS)shelf are essential for understanding the depositional dynamics environment in the ECS.The sediments in the northern ECS shelf are distributed in a ring-shaped distribution centered on the southwestern Cheju Island Mud.From the inside to the outside,the grain size goes from fine to coarse.Aside from the“grain size effect”,hydrodynamic sorting and mineral composition are important restrictions on the content of rare earth elements(REEs).Based on the grain size,REEs,and clay mineral composition of 300 surface sediments,as well as the sedimentary genesis,the northern ECS shelf is divided into three geochemical zones:southwestern Cheju Island Mud Area(ZoneⅠ),Changjiang Shoal Sand Ridges(ZoneⅡ-1),Sand Ridges of the East China Sea shelf(ZoneⅡ-2).The northern ECS shelf is mostly impacted by Chinese mainland rivers(the Changjiang River and Huanghe River),and the provenance and transport mechanism of sediments of different grain sizes is diverse.The bulk sediments come primarily from the Changjiang River,with some material from the Huanghe River carried by the Yellow Sea Coastal Current and the North Jiangsu Coastal Current,and less from Korean rivers.Among them,surface sediments in the southwestern Cheju Island Mud Area(ZoneⅠ)come mostly from the Changjiang River and partly from the Huanghe River.It was formed by the counterclockwise rotating cold eddies in the northern ECS shelf,which caused the sedimentation and accumulation of the fine-grained sediments of the Changjiang River and the Huanghe River.The Changjiang Shoal Sand Ridges(ZoneⅡ-1)were developed during the early-middle Holocene sea-level highstand.It is the modern tidal sand ridge sediment formed by intense hydrodynamic action under the influence of the Yellow Sea Coastal Current,North Jiangsu Coastal Current,and Changjiang Diluted Water.The surface sediments mainly originate from the Changjiang River and Huanghe River,with the Changjiang River dominating,and the Korean River(Hanjiang River)influencing just a few stations.Sand Ridges of the East China Sea shelf(ZoneⅡ-2)are the relict sediments of the paleo-Changjiang River created by sea invasion at the end of the Last Deglaciation in the Epipleistocene.The clay mineral composition of the surface sediments in the study area is just dominated by the Changjiang River,with the North Jiangsu Coastal Current and the Changjiang Diluted Water as the main transporting currents.
基金the National Natural Science Foundation of China,Nos.62272480 and 62072470and the National Science Foundation of Hunan Province,Nos.2021JJ30881 and 2020JJ4758.
文摘Knowledge graph(KG)fact prediction aims to complete a KG by determining the truthfulness of predicted triples.Reinforcement learning(RL)-based approaches have been widely used for fact prediction.However,the existing approaches largely suffer from unreliable calculations on rule confidences owing to a limited number of obtained reasoning paths,thereby resulting in unreliable decisions on prediction triples.Hence,we propose a new RL-based approach named EvoPath in this study.EvoPath features a new reward mechanism based on entity heterogeneity,facilitating an agent to obtain effective reasoning paths during random walks.EvoPath also incorporates a new postwalking mechanism to leverage easily overlooked but valuable reasoning paths during RL.Both mechanisms provide sufficient reasoning paths to facilitate the reliable calculations of rule confidences,enabling EvoPath to make precise judgments about the truthfulness of prediction triples.Experiments demonstrate that EvoPath can achieve more accurate fact predictions than existing approaches.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41272170)Nature Science Foundation of Hubei Province (Grant No. 2013CFB97)
文摘Saturated fractions in a total of 23 oil samples and hydrocarbon source rocks from the Songliao, Tarim,and Ordos Basins have been analyzed by GC–MS and GC–MS–MS. According to the relative retention, mass spectral characteristics, and comparison with existing literature, a complete carbon number distribution ranging from C27 to C35(without C28) in the 17a(H)-diahopane series and early-eluting rearranged hopane series is identified. Compounds in the 18a(H)-neohopane series(Ts and C29Ts) and21-methyl-28-nor-hopane series(29Nsp and 30Nsp) are also noted. These four series of rearranged hopanes seem to occur in both brackish-saline lacustrine and coal measure environments. However, the coal measure and swamp environments being under an oxic condition, compared with brackish-saline lacustrines, are presumably more helpful to the formation of 30 E. Diversity in the content and distribution patterns indicate that rearranged hopanes could serve as good indicators of organic facies, depositional environment and maturity in petroleum geology.
文摘A simple and high throughput method was developed and validated for simultaneous determination of valproic acid and its two toxicant ene-metabolites, 2-enevalproic acid and 4-enevalproic acid in epilepsy patient plasma using liquid chromatography-tandem mass spectrometry. Probenecid was used as in- ternal standard and solid-phase extraction was selected for sample preparation. A chromatographic separation was performed on an Agilent Poroshell SB-C18 column (50 mm × 4.6 mm i.d., 2.7μm) by an optimized gradient elution at a flow rate of 0.9 mL/min. The total run time was 7 rain. Electrospray ionization was used in negative ion mode by multiple reaction monitoring of the precursor-to-product ion transitions at m/z 143.0→143.0 for valproic acid, m/z 140.9 →140.9 for 2-enevalproic acid and 4-enevalproic acid for their poor fragments, and m/z 283.9→239,9 for probenecid. The results showed good linearity ofvalproic acid, 2-enevalproic acid and 4-enevalproic acid in their respective linear ranges. The correlation coefficients were more than 0.998, The intra- and inter-day precision of the assay was less than 11.0% and the accuracy ranged from 2% to 12%. This analytical method was successfully applied to assay plasma concentrations of valproic acid and its two ene-metabolites in epilepsy patient plasma and used for therapeutic drug monitoring.
基金Natural Science Foundation of China(T11036061/T0108).
文摘A novel study using LCeMS(Liquid chromatography tandem mass spectrometry)coupled with multivariate data analysis and bioactivity evaluation was established for discrimination of aqueous extract and vinegar extract of Shixiao San.Batches of these two kinds of samples were subjected to analysis,and the datasets of sample codes,tR-m/z pairs and ion intensities were processed with principal component analysis(PCA).The result of score plot showed a clear classification of the aqueous and vinegar groups.And the chemical markers having great contributions to the differentiation were screened out on the loading plot.The identities of the chemical markers were performed by comparing the mass fragments and retention times with those of reference compounds and/or the known compounds published in the literatures.Based on the proposed strategy,quercetin-3-Oneohesperidoside,isorhamnetin-3-O-neohespeeridoside,kaempferol-3-O-neohesperidoside,isorhamnetin-3-O-rutinoside and isorhamnetin-3-O-(2G-a-l-rhamnosyl)-rutinoside were explored as representative markers in distinguishing the vinegar extract from the aqueous extract.The anti-hyperlipidemic activities of two processed extracts of Shixiao San were examined on serum levels of lipids,lipoprotein and blood antioxidant enzymes in a rat hyperlipidemia model,and the vinegary extract,exerting strong lipid-lowering and antioxidative effects,was superior to the aqueous extract.Therefore,boiling with vinegary was predicted as the greatest processing procedure for anti-hyperlipidemic effect of Shixiao San.Furthermore,combining the changes in the metabolic profiling and bioactivity evaluation,the five representative markers may be related to the observed antihyperlipidemic effect.
基金supported in part by a grant of the Scientific Research Program of Hainan Province (ZDYF2016143), China
文摘A simple, rapid and sensitive method based on an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C18 column (100 mm × 2.1 mm, 1.7μm; Waters, USA), with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate (70:30, v/v), at a flow rate of 0.2 mL/min for 2.5 rain. The analyte and clarithromyein (the internal standard) were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 - 223.0 for pimavanserin and m/z 748.5 - 589.5 for clarithromycin. Relative coefficient (r) for the calibration curve was more than 0.9980. The intra-day and inter-day precisions (relative standard deviation, RSD%) were less than 13.3% and 10.5%, respectively, and the accuracy (relative error, RE%) was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.
文摘The present study was designed to investigate the influence of the pretreatment of piperazine ferulate on pharmacokinetic parameters of methotrexate in methotrexate-induced renal injury rats.A simple and efficient high performance liquid chromatography coupled with mass spectrometry(HPLC-MS)method was developed to determine methotrexate in rat plasma.Methotrexate and syringic acid(internal standard)were extracted from rat plasma samples by protein precipitation with acetonitrile.The analysis was performed on a CAPCELL PAK C18column(150 mm×4.6 mm,5μm)with acetonitrile and 5 mmol/l ammonium acetate aqueous(10:90,v/v).The linear range was 5.0×10-2to 100.0μg/ml for methotrexate.Other parameters were all within the acceptance criteria.The validated method was successfully applied the pharmacokinetic study of methotrexate between two methotrexate treated groups(with and without the pretreatment of piperazine ferulate).Compared with the methotrexate treated alone group,the pharmacokinetic parameters in the methotrexate with the pretreatment of piperazine ferulate group showed significantly lower MRT(0-t),MRT(0-∞) and T1/2.Results suggested that methotrexate can be rapidly eliminated,cleared or metabolized in rat blood,which might be related to the pretreatment of piperazine ferulate.The method provided deeper insights into rational clinical use of methotrexate with the pretreatment of piperazine ferulate on cancer patients with renal dysfunction.
基金Supported by the National Natural Science Foundation of China(No.31702327)the Key Program for International S&T Cooperation Projects of China(No.2017YFE0111100-5)the Fund of Key Laboratory of Sustainable Development of Marine Fisheries,Ministry of Agriculture and Rural Aff airs of China and Central Public-interest Scientific Institution Basal Research Fund,Yellow Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences(No.20603022019020)。
文摘Strobilation is a well-organized metamorphosis process in scyphozoan jellyfi sh,through which the benthic polyp develops into the pelagic medusa.So far,knowledge on the molecular mechanisms behind the drastic morphological and physiological changes remains limited.In the present study,the metabolic profi les in polyp and strobila stages of jellyfi sh Rhopilema esculentum were examined using ultra-performance liquid chromatography coupled to a mass spectrometer.A total of 3071 metabolites with putative annotation were detected,of which 167 were identifi ed as diff erential metabolites between the polyp and strobila.Among the metabolites,31 signifi cantly decreased and 136 signifi cantly increased in abundance in the strobila.Thyroxin,one of the previously proposed strobilation inducer of Aurelia,was not detected in this study.The indole-containing compounds are known for triggering strobilation in Discomedusae.Two indole derivatives and an indole-isomer containing metabolite were detected among the most signifi cantly increased metabolites,which may be potential endogenous molecules for strobilation initiation.The membrane-associated phospholipids and the infl ammation and oxidative stress-related eicosanoids were found to have signifi cant changes.Although the functions of these metabolites in strobilation are not yet completely known,they provide some clues to the induction of the process of strobilation and metabolic responses that take place during strobilation.
基金supported by the National Basic Research Program of China(973 Program:2013CB329004)the Fundamental Research Funds for the Central Universities
文摘The explosive growth of data volume in mobile networks makes fast online diagnose a pressing search problem. In this paper, an object-oriented detection framework with a two-step clustering, named as Hourglass Clustering, is given. Where three object parameters are chosen as Synthetical Quality of Experience(SQo E) Key Quality Indicators(KQIs) to reflect accessibility, integrality, and maintainability of networks. Then, we choose represented Key Performance Indicators(r KPIs) as cause parameters with correlation analysis. For these two kinds of parameters, a hybrid algorithm combining the self-organizing map(SOM) and
文摘Larotaxel, a new taxane compound prepared by partial synthesis from 10-deacetyl baccatin III, is active against tumors. In this research, a selective LC–MS method was developed and validated for the study of degradation kinetics of larotaxel, which was carried out in aqueous solutions with different pH(1.5, 3.0, 5.0, 6.5, 7.4, 9.0, 10 and 11.0) and temperature(0, 25, 37 and 45 °C). The linear range was 0.5–25 μg/mL, the intra-and inter-day precisions were less than 7.0%, and accuracy ranged from 97.4–104.5% for each analyte. The observed rate obtained by measuring the remaining intact larotaxel was shown to follow first-order kinetics. The activation energies for degradation were 126.7 and 87.01 k J/mol at pH 1.5 and 11, respectively. Although larotaxel was stable in pH 5, 6.5 and 7.4 buffers at 37 °C for 24 h during our study, increasing or decreasing the pH of the solutions would decrease its stabilities. Moreover, three main degradation products in alkaline condition were separated by HPLC and identified by Q–TOF–MS. The three degradation products were confirmed as 10-deacetyl larotaxel, 7, 8-cyclopropyl baccatin Ⅲ and 10-deacetyl-7, 8-cyclopropyl baccatin Ⅲ.
文摘Cancer is the leading cause of death all over the world.Among the chemotherapy drugs,taxanes play an important role in cancer treatment.6258-70 is a new semi-synthetic taxane which has a broad spectrum of antitumor activity.A fast and reliable high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method was developed for quantification of 6258-70 in rat plasma and tissues in this paper.After extraction by liquid-liquid extraction method with methyl tert-butyl ether,the samples were separated on a Kinetex C_(18) column(50 mm × 2.1 mm,2.6 μm,Phenomenex,USA) within3 min.The method was fully validated with the matrix effect between 87.7%and 99.5%and the recovery ranging from 80.3%to 90.1%.The intra- and inter-day precisions were less than 9.5%and the accuracy ranged from-3.8%to 6.5%.The reliable method was successfully applied to the pharmacokinetics and tissue distribution studies of 6258-70 after intravenous administration in rats.The pharmacokinetic results indicated that the pharmacokinetic behavior of 6258-70 in rats was in accordance with linear features within tested dosage of 1 to 4 mg/kg,and there was no significant difference between the two genders.The tissue distribution study showed that 6258-70 had an effective penetration,spread widely and rapidly and could cross blood-brain barrier.The results of pharmacokinetics and tissue distribution may provide a guide for future study.
基金partially supported by grants from the The National Natural Science Foundation of China,China(81672749 and 22207093)Xiamen Bureau of Science&Technology,Xiamen city,China(3502Z20193004 and 3502Z20150007,China)+1 种基金Youth Innovation Fund from Xiamen City,Fujian Province,China.(3502Z20206033)the Fujian Provincial Key Laboratory of Innovative Drug Target Research,Fujian Province,China(FJYW-2022KF01,China)。
文摘The orphan nuclear receptor Nur77 is a critical regulator of the survival and death of tumor cells.The pro-death effect of Nur77 can be regulated by its interaction with Bcl-2,resulting in conversion of Bcl-2 from a survival to killer.As Bcl-2 is overexpressed in various cancers preventing them from apoptosis and promoting their resistance to chemotherapy,targeting the apoptotic pathway of Nur77/Bcl-2 may lead to new cancer therapeutics.Here,we report our identification of XS561 as a novel Nur77 ligand that induces apoptosis of tumor cells by activating the Nur77/Bcl-2 pathway.In vitro and animal studies revealed an apoptotic effect of XS561 in a range of tumor cell lines including MDA-MB-231 triple-negative breast cancer(TNBC)and MCF-7/LCC2 tamoxifen-resistant breast cancer(TAMR)in a Nur77-dependent manner.Mechanistic studies showed XS561 potently induced the translocation of Nur77 from the nucleus to mitochondria,resulting in mitochondria-related apoptosis.Interestingly,XS561-induced accumulation of Nur77 at mitochondria was associated with XS561 induction of Nur77 phase separation and the formation of Nur77/Bcl-2 condensates.Together,our studies identify XS561 as a new activator of the Nur77/Bcl-2 apoptotic pathway and reveal a role of phase separation in mediating the apoptotic effect of Nur77 at mitochondria.
基金supported by the National Key Research and Development Program of China(No.2022YFA1204900)the National Natural Science Foundation of China(Nos.52372038,12374035 and T2188101)the Innovation Program for Quantum Science and Technology(No.2021ZD0302600).
文摘Owing to the atomically thin nature,two-dimensional(2D)oxide materials have been widely reported to exhibit exciting transport and dielectric properties,such as fine gate controllability and ultrahigh carrier mobility,that outperform their bulk counterpart.However,unlike the successful synthesis of bulk oxide single crystals,reliable methods for synthesizing large-area single crystal of 2D oxide,that would suppress the negative influence from defective grain boundaries,remain unavailable,especially for nonlayered oxide.Herein,we report that the lattice symmetry between the substrate and cerium dioxide(CeO_(2))would allow for the aligned nucleation and epitaxial growth of CeO_(2)on sapphire substrates,enabling the wafer-sized growth of CeO_(2)single crystal.The careful tuning of the growth temperature and oxygen flow rate contributed to the harvesting of CeO_(2)wafer with reduced thickness and enhanced growth rates.The removal of grain boundaries improved the dielectric performance in terms of high dielectric strength(E_(bd)≈8.8 MV·cm^(-1)),suppressed leakage current,along with high dielectric constants(ε_(r)≈24).Our work demonstrates that with fine dielectric performance and ease of synthesizing wafer-sized single crystals,CeO_(2)can function as potential candidate as gate insulator for 2D-materials based nanoelectronics,and we believe the reported protocol of aligned nucleation can be extended to other 2D oxides.
基金supported by N ational Natural Science Foundation of China[grant number 41801313].
文摘Estimating the proportion of land-use types in different regions is essential to promote the organization of a compact city and reduce energy consumption.However,existing research in this area has a few limitations:(1)lack of consideration of land-use distribution-related factors other than POIs;(2)inability to extract complex relations from heterogeneous information;and(3)overlooking the correlation between land-use types.To overcome these limitations,we propose a knowledge-based approach for estimating land-use distributions.We designed a knowledge graph to display POIs and other related heterogeneous data and then utilized a knowledge embedding model to directly obtain the region embedding vectors by learning the complex and implicit relations present in the knowledge graph.Region embedding vectors were mapped to land-use distributions using a label distribution learning method integrating the correlation between land-use types.To prove the reliability and validity of our approach,we conducted a case study in Jinhua,China.The results indicated that the proposed model outperformed other algorithms in all evaluation indices,thus illustrating the potential of this method to achieve higher accuracy land-use distribution estimates.
基金supported by grants from the National Natural Science Foundation of China(grant Nos.81672932,81730108,81874380,and 81973635)the Zhejiang Provincial Natural Science Foundation of China for Distinguished Young Scholars(grant No.LR18H160001)+1 种基金the Zhejiang Province Science and Technology Project of TCM(grant No.2019ZZ016)the Open Project Program of the Jiangsu Key Laboratory of Pharmacology and Safety Evaluation of Chinese Materia Medica(No.JKLPSE201807).
文摘Ferroptosis,a novel form of programmed cell death,is characterized by iron-dependent lipid peroxidation and has been shown to be involved in multiple diseases,including cancer.Stimulating ferroptosis in cancer cells may be a potential strategy for cancer therapy.Therefore,ferroptosis-inducing drugs are attracting more attention for cancer treatment.Here,we showed that erianin,a natural product isolated from Dendrobium chrysotoxum Lindl,exerted its anticancer activity by inducing cell death and inhibiting cell migration in lung cancer cells.Subsequently,we demonstrated for the first time that erianin induced ferroptotic cell death in lung cancer cells,which was accompanied by ROS accumulation,lipid peroxidation,and GSH depletion.The ferroptosis inhibitors Fer-1 and Lip-1 but not Z-VAD-FMK,CQ,or necrostatin-1 rescued erianin-induced cell death,indicating that ferroptosis contributed to erianin-induced cell death.Furthermore,we demonstrated that Ca^(2+)/CaM signaling was a critical mediator of erianin-induced ferroptosis and that blockade of this signaling significantly rescued cell death induced by erianin treatment by suppressing ferroptosis.Taken together,our data suggest that the natural product erianin exerts its anticancer effects by inducing Ca^(2+)/CaMdependent ferroptosis and inhibiting cell migration,and erianin will hopefully serve as a prospective compound for lung cancer treatment.