The active components,targets,and pathways of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and the mechanism of action were explored by means of network pharmacology.Firstly,the active comp...The active components,targets,and pathways of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and the mechanism of action were explored by means of network pharmacology.Firstly,the active components and related targets of Jujubae Fructus were screened by TCMSP database and standardized by Uniprot database.The compounds of Euphorbia fischeriana Steud.were obtained by searching the literature and finally screened by PubChem database,Swiss ADME,and SwissTargetPrediction.Hepatocirrhosis targets were obtained through Genecards database,PPI network analysis was conducted on common targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis by using String database,GO enrichment analysis and KEGG pathway enrichment analysis was conducted through Metascape database by using intersection targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis,and the results were drawn by using Weishengxin online drawing platform.Then,the network of drug-compound-target-pathway was constructed by the software of Cytoscape3.8.0.Finally,the above results were verified by molecular docking.47 active compounds from Euphorbia fischeriana Steud.-Jujubae Fructus were screened out,which had 38 common targets,162 intersection targets,and 340 signal pathways with hepatocirrhosis,mainly involving hepatitis C,JAK-STAT signal pathway and AGE-RAGE signal pathway.Targets,such as MAPK1,AKT1,TNF,JUN,IL6 and PTGS2,play important roles in the treatment.The findings suggested that the main active ingredients of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis are quercetin,scopolamine,physcion,7-deoxyrangduin,17-Hydroxyjolkinolide A,etc.Molecular docking results showed that the main active components and core targets might have a good binding capacity.This study preliminarily explored the potential mechanism of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and provided a theoretical basis for the clinical application of Euphorbia fischeriana Steud.-Jujubae Fructus.展开更多
Stacking faults(SFs)are often present in silicon carbide(SiC)and affect its thermal and heat-transport properties.However,it is unclear how SFs influence thermal transport.Using non-equilibrium molecular dynamics and ...Stacking faults(SFs)are often present in silicon carbide(SiC)and affect its thermal and heat-transport properties.However,it is unclear how SFs influence thermal transport.Using non-equilibrium molecular dynamics and lattice dynamics simulations,we studied phonon transport in SiC materials with an SF.Compared to perfect SiC materials,the SF can reduce thermal conductivity.This is caused by the additional interface thermal resistance(ITR)of SF,which is difficult to capture by the previous phenomenological models.By analyzing the spectral heat flux,we find that SF reduces the contribution of low-frequency(7.5 THz-12 THz)phonons to the heat flux,which can be attributed to SF reducing the phonon lifetime and group velocity,especially in the low-frequency range.The SF hinders phonon transport and results in an effective interface thermal resistance around the SF.Our results provide insight into the microscopic mechanism of the effect of defects on heat transport and have guiding significance for the regulation of the thermal conductivity of materials.展开更多
[Objectives]The paper was to establish a rapid screening method of pesticide residues in strawberry based on HPLC-QTOF/MS SWATH acquisition mode.[Methods]The strawberry sample was extracted with acetonitrile,purified ...[Objectives]The paper was to establish a rapid screening method of pesticide residues in strawberry based on HPLC-QTOF/MS SWATH acquisition mode.[Methods]The strawberry sample was extracted with acetonitrile,purified with anhydrous magnesium sulfate,sodium chloride and primary secondary amine(PSA)powder,and then loaded on the machine.The full information spectrum was collected by positive ion mode and screened by comparing with the spectrum library,and 20 kinds of pesticide residues were quantitatively analyzed.[Results]The detection limits of 20 pesticide residues were 0.0002-0.0100 mg/kg,and they showed good linearity in the range of 0.0005-0.1000μg/mL(R 2≥0.995).The recoveries ranged from 62.8%to 106.3%.[Conclusions]This method is rapid,simple,sensitive and non-targeted,and can be used for rapid screening of multiple pesticide residues in strawberry.展开更多
<div style="text-align:justify;"> Knowledge tracking model has been a research hotspot in the field of educational data mining for a long time. Knowledge tracking can automatically discover students’ ...<div style="text-align:justify;"> Knowledge tracking model has been a research hotspot in the field of educational data mining for a long time. Knowledge tracking can automatically discover students’ weak knowledge points, which helps to improve students’ self-motivation in learning and realize personalized guidance. The existing KT model has some shortcomings, such as the limitation of the calculation of knowledge growth, and the imperfect forgetting mechanism of the model. To this end, we proposed a new knowledge tracking model based on learning process (LPKT), LPKT applies the idea of Memory Augmented Neural Net-work(MANN).When we model the learning process of students, two additional important factors are considered. One is to consider the current state of knowledge of the students when updating the dynamic matrix of the neural network, and the other is to improve the forgetting mechanism of the model. In this paper we verified the effectiveness and superiority of LPKT through comparative experiments, and proved that the model can improve the effect of knowledge tracking and make the process of deep knowledge tracking easier to understand. </div>展开更多
BACKGROUND Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs);however,there are few publications about the predictive factors for the outcomes of this treat...BACKGROUND Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs);however,there are few publications about the predictive factors for the outcomes of this treatment.AIM To assess the predictive factors for the outcomes of EBD treatment for strictures after esophageal atresia (EA) repair.METHODS Children with anastomotic ES after thoracoscopic esophageal atresia repair treated by EBD from January 2012 to December 2016 were included.All procedures were performed under tracheal intubation and intravenous anesthesia using a three-grade controlled radial expansion balloon with gastroscopy.Outcomes were recorded and predictors of the outcomes were analyzed.RESULTS A total of 64 patients were included in this analysis.The rates of response,complications,and recurrence were 96.77%,8.06%,and 2.33%,respectively.The number of dilatation sessions and complications were significantly higher in patients with a smaller stricture diameter (P=0.013 and 0.023,respectively) and with more than one stricture (P=0.014 and 0.004,respectively).The length of the stricture was significantly associated with complications of EBD (P=0.001).A longer interval between surgery and the first dilatation was related to more sessions and a poorer response (P=0.017 and 0.024,respectively).CONCLUSION The diameter,length,and number of strictures are the most important predictive factors for the clinical outcomes of endoscopic balloon dilatation in pediatric ES.The interval between surgery and the first EBD is another factor affectingresponse and the number of sessions of dilatation.展开更多
Persistent uplift means the Qinghai-Tibet Plateau(QTP)is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments.However,how paleogeographic and paleoclimatic events inf...Persistent uplift means the Qinghai-Tibet Plateau(QTP)is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments.However,how paleogeographic and paleoclimatic events influence the genome and population of endemic fish species remains unclear.Glyptosternon maculatum is an ancient endemic fish found on the QTP and the only critically endangered species in the Sisoridae family.Here,we found that major transposons in the G.maculatum genome showed episodic bursts,consistent with contemporaneous geological and climatic events during the QTP formation.Notably,histone genes showed significant expansion in the G.maculatum genome,which may be mediated by long interspersed nuclear elements(LINE)repetitive element duplications.Population analysis showed that ancestral G.maculatum populations experienced two significant depressions 2.6 million years ago(Mya)and 10000 years ago,exhibiting excellent synchronization with Quaternary glaciation and the Younger Dryas,respectively.Thus,we propose that paleogeography and paleoclimate were dominating driving forces for population dynamics in endemic fish on the QTP.Tectonic movements and temperature fluctuation likely destroyed the habitat and disrupted the drainage connectivity among populations.These factors may have caused severe bottlenecks and limited migration among ancestral G.maculatum populations,resulting in the low genetic diversity and endangered status of the species today.展开更多
Fish morphological phenotypes are important resources in artificial breeding,functional gene mapping,and population-based studies in aquaculture and ecology.Traditional morphological measurement of phenotypes is rathe...Fish morphological phenotypes are important resources in artificial breeding,functional gene mapping,and population-based studies in aquaculture and ecology.Traditional morphological measurement of phenotypes is rather expensive in terms of time and labor.More importantly,manual measurement is highly dependent on operational experience,which can lead to subjective phenotyping results.Here,we developed 3DPhenoFish software to extract fish morphological phenotypes from three-dimensional(3D)point cloud data.Algorithms for background elimination,coordinate normalization,image segmentation,key point recognition,and phenotype extraction were developed and integrated into an intuitive user interface.Furthermore,18 key points and traditional 2D morphological traits,along with 3D phenotypes,including area and volume,can be automatically obtained in a visualized manner.Intuitive fine-tuning of key points and customized definitions of phenotypes are also allowed in the software.Using 3DPhenoFish,we performed high-throughput phenotyping for four endemic Schizothoracinae species,including Schizopygopsis younghusbandi,Oxygymnocypris stewartii,Ptychobarbus dipogon,and Schizothorax oconnori.Results indicated that the morphological phenotypes from 3DPhenoFish exhibited high linear correlation(>0.94)with manual measurements and offered informative traits to discriminate samples of different species and even for different populations of the same species.In summary,we developed an efficient,accurate,and customizable tool,3DPhenoFish,to extract morphological phenotypes from point cloud data,which should help overcome traditional challenges in manual measurements.3DPhenoFish can be used for research on morphological phenotypes in fish,including functional gene mapping,artificial selection,and conservation studies.3DPhenoFish is an open-source software and can be downloaded for free at https://github.com/lyh24k/3DPhenoFish/tree/master.展开更多
BACKGROUND Gastrointestinal cytomegalovirus(CMV)disease occurs commonly in immunocompromised/immunodeficient patients with advanced human immunodeficiency virus infection,neoplasm,solid organ transplantation,hematopoi...BACKGROUND Gastrointestinal cytomegalovirus(CMV)disease occurs commonly in immunocompromised/immunodeficient patients with advanced human immunodeficiency virus infection,neoplasm,solid organ transplantation,hematopoietic stem cell transplantation,or treatment with immunosuppressants,but is rarely reported in association with measles infection.CASE SUMMARY We describe a case of extensive gastrointestinal CMV disease secondary to measles infection in a 9-mo-old boy who presented with persistent fever and bloody diarrhea.His condition was improved after ganciclovir treatment.Serological analysis of CMV showed negative immunoglobulin(Ig)M and positive IgG.Blood CMV-DNA was 9.26×103 copies/mL.The diagnosis of gastrointestinal CMV disease was confirmed by histopathological findings of intranuclear and intracytoplasmic inclusions and Owl’s eye inclusion.This case highlights the differential diagnosis and histopathological characteristics of gastrointestinal CMV infection and laboratory tests.CONCLUSION Extensive gastrointestinal CMV lesions can be induced by the immune suppression secondary to measles infection.Rational,fast,and effective laboratory examinations are essential for suspected patients.展开更多
The pneumonia caused by the coronavirus disease-2019(COVID-19)outbreak in Wuhan,China constitutes a public health emergency of international concern.The gastrointestinal symptoms of vomiting,diarrhea and abdominal pai...The pneumonia caused by the coronavirus disease-2019(COVID-19)outbreak in Wuhan,China constitutes a public health emergency of international concern.The gastrointestinal symptoms of vomiting,diarrhea and abdominal pain and the detection of COVID-19 nucleic acid from fecal specimens in a small number of patients suggest the possibility of transmission via the gastrointestinal tract.People of all ages are vulnerable to this virus,including children.Digestive endoscopy is an invasive procedure during which children cannot wear masks;therefore,they have higher risks of exposure to COVID-19,and the digestive endoscopy center is a relatively high-risk area for COVID-19 infection.Based on these factors and in combination with related policies and regulations,a prevention and control program for the COVID-19 pneumonia in a children's digestive endoscopy center was established to prevent the COVID-19 nosocomial infection.展开更多
Aerosol optical properties and direct radiative effects on surface irradiance were examined using seven years (2006-2012) of Cimel sunphotometer data collected at Panyu--the main atmospheric composition monitoring s...Aerosol optical properties and direct radiative effects on surface irradiance were examined using seven years (2006-2012) of Cimel sunphotometer data collected at Panyu--the main atmospheric composition monitoring station in the Pearl River Delta (PRD) region of China. During the dry season (October to February), mean values of the aerosol optical depth (AOD) at 550 nm, the Angstrom exponent, and the single scattering albedo at 440 nm (SSA) were 0.54, 1.33 and 0.87, respectively. About 90% of aerosols were dominated by fine-mode strongly absorbing particles. The size distribution was bimodal, with fine-mode particles dominating. The fine mode showed a peak at a radius of 0.12 μm in February and October (- 0.10 μm3 μm-2). The mean diurnal shortwave direct radiative forcing at the surface, inside the atmosphere (FATM), and at the top of the atmosphere, was -33.4± 7.0, 26.1 ± 5.6 and -7.3 ±2.7 W m-2, respectively. The corresponding mean values of aerosol direct shortwave radiative forcing per AOD were -60.0 ±7.8, 47.3 ± 8.3 and -12.8 ±3.1 W m-2, respectively. Moreover, during the study period, FATM showed a significant decreasing trend (p 〈 0.01) and SSA increased from 0.87 in 2006 to 0.91 in 2012, suggesting a decreasing trend of absorbing particles being released into the atmosphere. Optical properties and radiative impacts of the absorbing particles can be used to improve the accuracy of inversion algorithms for satellite-based aerosol retrievals in the PRD region and to better constrain the climate effect of aerosols in climate models.展开更多
Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency an...Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency and stability of perovskite solar cells.Here,an organic halide salt pyridinium iodide(PyI) is used in cation-anion-mixed perovskite for surface defect passivation.Different from the treatment with Lewis base pyridine(Py) which can only bind to the under-coordinated Pb ions,zwitterion molecule PyI can not only fill negative charged iodine vacancies,but also interact with positive charged defects.Compared with Py treatment,PyI treatment results in smoother surface,less defect densities and nonradiative recombination in perovskite,leading to an improved VOC, negligible J-V hysteresis and stable performance of devices.As a result,the champion PyI-treated planar perovskite solar cell with a high VOC of 1.187 V achieves an efficiency of 21.42%,which is higher than 20.37% of Py-treated device,while the pristine device without any treatment gets an efficiency of 18.83% at the same experiment conditions.展开更多
The Tibetan Plateau, known as "the roof of the world" and "the third pole of the earth", is a product of the collision between India and Asia during the last ~50 Ma.The regional tectonics–in part...The Tibetan Plateau, known as "the roof of the world" and "the third pole of the earth", is a product of the collision between India and Asia during the last ~50 Ma.The regional tectonics–in particular, growth and expansion of the plateau–has been attributed primarily to deformation within the lithosphere.The role and pattern of the underlying asthenospheric flow, however, remain mostly unaddressed.In light of recent seismic tomographic images and published seismic anisotropic descriptions of the upper mantle, here we propose that an entrained mantle flow is likely to exist under Tibet, induced by the northward advancing Indian plate.The direction of mantle flow is characterized by a gradual rotation from northward in the south to eastward in the north as a result of deflection by the deep root of the Tarim block.The presence of an underlying mantle flow is not only able to account for the west-east oriented fast-axis of seismic anisotropy in northern Tibet, but can also adequately explain the sporadic null splitting in southern Tibet.Specifically, the null splitting results, at least in part, from upwellings of asthenospheric flow through tears of the underthrusting Indian plate that have been revealed by various seismic observations.The mantle flow may in turn promote the block extrusion under Tibet that has been observed in GPS measurements; hot asthenospheric upwellings may also lead to widespread post-collisional magmatism in southern Tibet.展开更多
With great achievements in efficiency,stability,and large-scale preparation of perovskite solar cells(PSCs),the com-mercialization of PSC is ongoing,but there is still an issue on lead toxicity.Although lead content i...With great achievements in efficiency,stability,and large-scale preparation of perovskite solar cells(PSCs),the com-mercialization of PSC is ongoing,but there is still an issue on lead toxicity.Although lead content in the device is low,the water solubility of lead salts leads to potential environmental pollution.At present,the non-lead perovskites studied in-clude:divalent metal perovskite(e.g.,Sn^(2+),Ge^(2+),Cu^(2+)),trivalent metal perovskite(e.g.,Bi^(3+),Sb^(3+),In^(3+)),tetravalent met-al double perovskite(e.g.,Sn^(4+),Pd^(4+),Ti^(4+),Pt^(4+))and mono-trivalent mixed double perovskite(e.g.,Ag+and Bi^(3+),Ag+and In^(3+),Ag^(+)and Sb^(3+)).Their properties are summarized in Table 1.Since the first report on non-lead double perovskite Cs2AgBiBr6 in 2016^([1]).展开更多
On the process of power system black start after an accident, it can help to optimize the resources allocation and accelerate the recovery process that decomposing the power system into several independent partitions ...On the process of power system black start after an accident, it can help to optimize the resources allocation and accelerate the recovery process that decomposing the power system into several independent partitions for parallel recovery. On the basis of adequate consideration of fuzziness of black-start zone partitioning, a new algorithm based on fuzzy clustering analysis is presented. Characteristic indexes are extracted fully and accurately. The raw data matrix is made up of the electrical distance between every nodes and blackstart resources. Closure transfer method is utilized to get the dynamic clustering. The availability and feasibility of the proposed algorithm are verified on the New-England 39 bus system at last.展开更多
Among the end-users of the power grid,especially in the rural power grid,there are a large number of users and the situation is complex.In this complex situation,there are more leakage caused by insulation damage and ...Among the end-users of the power grid,especially in the rural power grid,there are a large number of users and the situation is complex.In this complex situation,there are more leakage caused by insulation damage and a small number of users stealing electricity.Maintenance staff will take a long time to determine the location of the abnormal user meter box.In view of this situation,themethod of subjective fuzzy clustering and quartile difference is adopted to determine the partition threshold.The power consumption data of end-users are divided into three regions:high,normal and low,which can be used to screen users in the area of abnormal power consumption.Then the trend judgment method is used to further accurately screen to improve the accuracy and reduce the number of users in the abnormal range.Finally according to abnormal power consumption auxiliary locate abnormal electricity users list box.Then the simulation environment is set to verify the application of membership fuzzy clustering and trend judgment in power consumption data partition.展开更多
Lyrics retrieval is one of the frequently-used retrieval functions of search engines. However, diversified information requirements are neglected in the existing lyrics retrieval systems. A lyrics retrieval system nam...Lyrics retrieval is one of the frequently-used retrieval functions of search engines. However, diversified information requirements are neglected in the existing lyrics retrieval systems. A lyrics retrieval system named LRC Sousou, in which erroneous characters are corrected automatically, the mixed queries of Chinese words and Pinyin are supported, and English phonemes queries are also achieved effectively, is introduced in this paper. The technologies of natural language processing, information retrieval and machine learning algorithm are applied to our lyrics retrieval system which enhance the practicability and efficiency of lyrics search, and improve user experience.展开更多
Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,...Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,the propagatingvariant width of this beam can be flexibly predesigned.We experimentally demonstrate three types of self-similar Bessellike beams whose width variations are linear,piecewise,and period functions of propagation distance,respectively.The experimental results match well with the theoretical predictions.We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.展开更多
Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constan...Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constantly being broken and has recently reached 26.1%in the lab,which is comparable to the established photovoltaic technologies such as crystalline silicon,copper indium gallium selenide and cadmium telluride(CdTe)solar cells.Currently,perovskite solar cells are standing at the entrance of industrialization,where huge opportunities and risks coexist.However,towards commercialization,challenges of up-scaling,stability and lead toxicity still remain,the proper handling of which could potentially lead to the widespread adoption of perovskite solar cells as a low-cost and efficient source of renewable energy.This review gives a holistic analysis of the path towards commercialization for perovskite solar cells.A comprehensive overview of the current state-of-the-art level for perovskite solar cells and modules will be introduced first,with respect to the module efficiency,stability and current status of industrialization.We will then discuss the challenges that get in the way of commercialization and the corresponding strategies to address them,involving the upscaling,the stability and the lead toxicity issue.Insights into the future direction of commercialization of perovskite photovoltaics was also provided,including the flexible perovskite cells and modules and perovskite indoor photovoltaics.Finally,the future perspectives towards commercialization are put forward.展开更多
The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wa...The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element.The tilted Bessel beam shows a detectable photonic spin Hall effect.By introducing the nonlinear propagation trajectories,the spin Hall effect is greatly enhanced.More surprisingly,the two spin states exactly propagate along the scaled trajectories,enabling flexible control of the spin separation.This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories,which have been already reported.展开更多
基金supported by Qiqihar Science and Technology Plan Joint Guidance Project (LSFGG-2022042).
文摘The active components,targets,and pathways of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and the mechanism of action were explored by means of network pharmacology.Firstly,the active components and related targets of Jujubae Fructus were screened by TCMSP database and standardized by Uniprot database.The compounds of Euphorbia fischeriana Steud.were obtained by searching the literature and finally screened by PubChem database,Swiss ADME,and SwissTargetPrediction.Hepatocirrhosis targets were obtained through Genecards database,PPI network analysis was conducted on common targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis by using String database,GO enrichment analysis and KEGG pathway enrichment analysis was conducted through Metascape database by using intersection targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis,and the results were drawn by using Weishengxin online drawing platform.Then,the network of drug-compound-target-pathway was constructed by the software of Cytoscape3.8.0.Finally,the above results were verified by molecular docking.47 active compounds from Euphorbia fischeriana Steud.-Jujubae Fructus were screened out,which had 38 common targets,162 intersection targets,and 340 signal pathways with hepatocirrhosis,mainly involving hepatitis C,JAK-STAT signal pathway and AGE-RAGE signal pathway.Targets,such as MAPK1,AKT1,TNF,JUN,IL6 and PTGS2,play important roles in the treatment.The findings suggested that the main active ingredients of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis are quercetin,scopolamine,physcion,7-deoxyrangduin,17-Hydroxyjolkinolide A,etc.Molecular docking results showed that the main active components and core targets might have a good binding capacity.This study preliminarily explored the potential mechanism of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and provided a theoretical basis for the clinical application of Euphorbia fischeriana Steud.-Jujubae Fructus.
基金Sichuan Science and Technology Program(Grant No.2023NSFSC0044)the National Natural Science Foundation of China(Grant No.51501119)+1 种基金the Fundamental Research Funds for the Central Universitiespartially supported by the High-Performance Computing Center at Sichuan University。
文摘Stacking faults(SFs)are often present in silicon carbide(SiC)and affect its thermal and heat-transport properties.However,it is unclear how SFs influence thermal transport.Using non-equilibrium molecular dynamics and lattice dynamics simulations,we studied phonon transport in SiC materials with an SF.Compared to perfect SiC materials,the SF can reduce thermal conductivity.This is caused by the additional interface thermal resistance(ITR)of SF,which is difficult to capture by the previous phenomenological models.By analyzing the spectral heat flux,we find that SF reduces the contribution of low-frequency(7.5 THz-12 THz)phonons to the heat flux,which can be attributed to SF reducing the phonon lifetime and group velocity,especially in the low-frequency range.The SF hinders phonon transport and results in an effective interface thermal resistance around the SF.Our results provide insight into the microscopic mechanism of the effect of defects on heat transport and have guiding significance for the regulation of the thermal conductivity of materials.
基金Supported by Scientific Research Project of General Administration of Customs (2021DK16).
文摘[Objectives]The paper was to establish a rapid screening method of pesticide residues in strawberry based on HPLC-QTOF/MS SWATH acquisition mode.[Methods]The strawberry sample was extracted with acetonitrile,purified with anhydrous magnesium sulfate,sodium chloride and primary secondary amine(PSA)powder,and then loaded on the machine.The full information spectrum was collected by positive ion mode and screened by comparing with the spectrum library,and 20 kinds of pesticide residues were quantitatively analyzed.[Results]The detection limits of 20 pesticide residues were 0.0002-0.0100 mg/kg,and they showed good linearity in the range of 0.0005-0.1000μg/mL(R 2≥0.995).The recoveries ranged from 62.8%to 106.3%.[Conclusions]This method is rapid,simple,sensitive and non-targeted,and can be used for rapid screening of multiple pesticide residues in strawberry.
文摘<div style="text-align:justify;"> Knowledge tracking model has been a research hotspot in the field of educational data mining for a long time. Knowledge tracking can automatically discover students’ weak knowledge points, which helps to improve students’ self-motivation in learning and realize personalized guidance. The existing KT model has some shortcomings, such as the limitation of the calculation of knowledge growth, and the imperfect forgetting mechanism of the model. To this end, we proposed a new knowledge tracking model based on learning process (LPKT), LPKT applies the idea of Memory Augmented Neural Net-work(MANN).When we model the learning process of students, two additional important factors are considered. One is to consider the current state of knowledge of the students when updating the dynamic matrix of the neural network, and the other is to improve the forgetting mechanism of the model. In this paper we verified the effectiveness and superiority of LPKT through comparative experiments, and proved that the model can improve the effect of knowledge tracking and make the process of deep knowledge tracking easier to understand. </div>
基金Supported by the Shenzhen Innovation and Technology Committee,No.JCYJ20180228175150018the Guangdong Medical Research Foundation(CN),No.A2018550
文摘BACKGROUND Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs);however,there are few publications about the predictive factors for the outcomes of this treatment.AIM To assess the predictive factors for the outcomes of EBD treatment for strictures after esophageal atresia (EA) repair.METHODS Children with anastomotic ES after thoracoscopic esophageal atresia repair treated by EBD from January 2012 to December 2016 were included.All procedures were performed under tracheal intubation and intravenous anesthesia using a three-grade controlled radial expansion balloon with gastroscopy.Outcomes were recorded and predictors of the outcomes were analyzed.RESULTS A total of 64 patients were included in this analysis.The rates of response,complications,and recurrence were 96.77%,8.06%,and 2.33%,respectively.The number of dilatation sessions and complications were significantly higher in patients with a smaller stricture diameter (P=0.013 and 0.023,respectively) and with more than one stricture (P=0.014 and 0.004,respectively).The length of the stricture was significantly associated with complications of EBD (P=0.001).A longer interval between surgery and the first dilatation was related to more sessions and a poorer response (P=0.017 and 0.024,respectively).CONCLUSION The diameter,length,and number of strictures are the most important predictive factors for the clinical outcomes of endoscopic balloon dilatation in pediatric ES.The interval between surgery and the first EBD is another factor affectingresponse and the number of sessions of dilatation.
基金supported by the Key Research and Development Projects in Tibet:Preservation of Characteristic Biological Germplasm Resources and Utilization of Gene Technology in Tibet(XZ202001ZY0016N)National Natural Science Foundation of China(32072980)Special Finance of Tibet Autonomous Region(XZNKY-2019-C-053)。
文摘Persistent uplift means the Qinghai-Tibet Plateau(QTP)is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments.However,how paleogeographic and paleoclimatic events influence the genome and population of endemic fish species remains unclear.Glyptosternon maculatum is an ancient endemic fish found on the QTP and the only critically endangered species in the Sisoridae family.Here,we found that major transposons in the G.maculatum genome showed episodic bursts,consistent with contemporaneous geological and climatic events during the QTP formation.Notably,histone genes showed significant expansion in the G.maculatum genome,which may be mediated by long interspersed nuclear elements(LINE)repetitive element duplications.Population analysis showed that ancestral G.maculatum populations experienced two significant depressions 2.6 million years ago(Mya)and 10000 years ago,exhibiting excellent synchronization with Quaternary glaciation and the Younger Dryas,respectively.Thus,we propose that paleogeography and paleoclimate were dominating driving forces for population dynamics in endemic fish on the QTP.Tectonic movements and temperature fluctuation likely destroyed the habitat and disrupted the drainage connectivity among populations.These factors may have caused severe bottlenecks and limited migration among ancestral G.maculatum populations,resulting in the low genetic diversity and endangered status of the species today.
基金supported by the National Natural Science Foundation of China(32072980)Key Research and Development Projects in Tibet(XZ202001ZY0016N,XZ201902NB02,XZNKY-2019-C-053)。
文摘Fish morphological phenotypes are important resources in artificial breeding,functional gene mapping,and population-based studies in aquaculture and ecology.Traditional morphological measurement of phenotypes is rather expensive in terms of time and labor.More importantly,manual measurement is highly dependent on operational experience,which can lead to subjective phenotyping results.Here,we developed 3DPhenoFish software to extract fish morphological phenotypes from three-dimensional(3D)point cloud data.Algorithms for background elimination,coordinate normalization,image segmentation,key point recognition,and phenotype extraction were developed and integrated into an intuitive user interface.Furthermore,18 key points and traditional 2D morphological traits,along with 3D phenotypes,including area and volume,can be automatically obtained in a visualized manner.Intuitive fine-tuning of key points and customized definitions of phenotypes are also allowed in the software.Using 3DPhenoFish,we performed high-throughput phenotyping for four endemic Schizothoracinae species,including Schizopygopsis younghusbandi,Oxygymnocypris stewartii,Ptychobarbus dipogon,and Schizothorax oconnori.Results indicated that the morphological phenotypes from 3DPhenoFish exhibited high linear correlation(>0.94)with manual measurements and offered informative traits to discriminate samples of different species and even for different populations of the same species.In summary,we developed an efficient,accurate,and customizable tool,3DPhenoFish,to extract morphological phenotypes from point cloud data,which should help overcome traditional challenges in manual measurements.3DPhenoFish can be used for research on morphological phenotypes in fish,including functional gene mapping,artificial selection,and conservation studies.3DPhenoFish is an open-source software and can be downloaded for free at https://github.com/lyh24k/3DPhenoFish/tree/master.
基金Shenzhen Innovation and Technology Committee,No.JCYJ20180228175150018.
文摘BACKGROUND Gastrointestinal cytomegalovirus(CMV)disease occurs commonly in immunocompromised/immunodeficient patients with advanced human immunodeficiency virus infection,neoplasm,solid organ transplantation,hematopoietic stem cell transplantation,or treatment with immunosuppressants,but is rarely reported in association with measles infection.CASE SUMMARY We describe a case of extensive gastrointestinal CMV disease secondary to measles infection in a 9-mo-old boy who presented with persistent fever and bloody diarrhea.His condition was improved after ganciclovir treatment.Serological analysis of CMV showed negative immunoglobulin(Ig)M and positive IgG.Blood CMV-DNA was 9.26×103 copies/mL.The diagnosis of gastrointestinal CMV disease was confirmed by histopathological findings of intranuclear and intracytoplasmic inclusions and Owl’s eye inclusion.This case highlights the differential diagnosis and histopathological characteristics of gastrointestinal CMV infection and laboratory tests.CONCLUSION Extensive gastrointestinal CMV lesions can be induced by the immune suppression secondary to measles infection.Rational,fast,and effective laboratory examinations are essential for suspected patients.
文摘The pneumonia caused by the coronavirus disease-2019(COVID-19)outbreak in Wuhan,China constitutes a public health emergency of international concern.The gastrointestinal symptoms of vomiting,diarrhea and abdominal pain and the detection of COVID-19 nucleic acid from fecal specimens in a small number of patients suggest the possibility of transmission via the gastrointestinal tract.People of all ages are vulnerable to this virus,including children.Digestive endoscopy is an invasive procedure during which children cannot wear masks;therefore,they have higher risks of exposure to COVID-19,and the digestive endoscopy center is a relatively high-risk area for COVID-19 infection.Based on these factors and in combination with related policies and regulations,a prevention and control program for the COVID-19 pneumonia in a children's digestive endoscopy center was established to prevent the COVID-19 nosocomial infection.
基金funded by the National Natural Science Foundation of China (Grant Nos. 41475105, 41475138,41405133 and 41605105)the National Key Project of MOST (Grant No. 2016YFC0202003, 2016YFC0203305, 2016YFC0201901)+2 种基金the Guangdong Province Science and Technology Plan (Grant No. 2015A020215020)the Science and Technology Innovative Research Team Plan of Guangdong Meteorological Bureau (Grant No. 201506)the Science and Technology Research Project of Guangdong Meteorological Bureau (Grant No. 2015B06)
文摘Aerosol optical properties and direct radiative effects on surface irradiance were examined using seven years (2006-2012) of Cimel sunphotometer data collected at Panyu--the main atmospheric composition monitoring station in the Pearl River Delta (PRD) region of China. During the dry season (October to February), mean values of the aerosol optical depth (AOD) at 550 nm, the Angstrom exponent, and the single scattering albedo at 440 nm (SSA) were 0.54, 1.33 and 0.87, respectively. About 90% of aerosols were dominated by fine-mode strongly absorbing particles. The size distribution was bimodal, with fine-mode particles dominating. The fine mode showed a peak at a radius of 0.12 μm in February and October (- 0.10 μm3 μm-2). The mean diurnal shortwave direct radiative forcing at the surface, inside the atmosphere (FATM), and at the top of the atmosphere, was -33.4± 7.0, 26.1 ± 5.6 and -7.3 ±2.7 W m-2, respectively. The corresponding mean values of aerosol direct shortwave radiative forcing per AOD were -60.0 ±7.8, 47.3 ± 8.3 and -12.8 ±3.1 W m-2, respectively. Moreover, during the study period, FATM showed a significant decreasing trend (p 〈 0.01) and SSA increased from 0.87 in 2006 to 0.91 in 2012, suggesting a decreasing trend of absorbing particles being released into the atmosphere. Optical properties and radiative impacts of the absorbing particles can be used to improve the accuracy of inversion algorithms for satellite-based aerosol retrievals in the PRD region and to better constrain the climate effect of aerosols in climate models.
基金the joint financial support from the National Natural Science Foundation of China (No. U1705256, 51972123, 21771066 and 61804058)the Cultivation Program for Postgraduate in Scientific Research Innovation Ability of Huaqiao University (No. 18014087027)。
文摘Perovskite solar cells have developed rapidly in the past decades.However,there are large amounts of ionic defects at the surface and grain boundaries of perovskte films which are detrimental to both the efficiency and stability of perovskite solar cells.Here,an organic halide salt pyridinium iodide(PyI) is used in cation-anion-mixed perovskite for surface defect passivation.Different from the treatment with Lewis base pyridine(Py) which can only bind to the under-coordinated Pb ions,zwitterion molecule PyI can not only fill negative charged iodine vacancies,but also interact with positive charged defects.Compared with Py treatment,PyI treatment results in smoother surface,less defect densities and nonradiative recombination in perovskite,leading to an improved VOC, negligible J-V hysteresis and stable performance of devices.As a result,the champion PyI-treated planar perovskite solar cell with a high VOC of 1.187 V achieves an efficiency of 21.42%,which is higher than 20.37% of Py-treated device,while the pristine device without any treatment gets an efficiency of 18.83% at the same experiment conditions.
文摘The Tibetan Plateau, known as "the roof of the world" and "the third pole of the earth", is a product of the collision between India and Asia during the last ~50 Ma.The regional tectonics–in particular, growth and expansion of the plateau–has been attributed primarily to deformation within the lithosphere.The role and pattern of the underlying asthenospheric flow, however, remain mostly unaddressed.In light of recent seismic tomographic images and published seismic anisotropic descriptions of the upper mantle, here we propose that an entrained mantle flow is likely to exist under Tibet, induced by the northward advancing Indian plate.The direction of mantle flow is characterized by a gradual rotation from northward in the south to eastward in the north as a result of deflection by the deep root of the Tarim block.The presence of an underlying mantle flow is not only able to account for the west-east oriented fast-axis of seismic anisotropy in northern Tibet, but can also adequately explain the sporadic null splitting in southern Tibet.Specifically, the null splitting results, at least in part, from upwellings of asthenospheric flow through tears of the underthrusting Indian plate that have been revealed by various seismic observations.The mantle flow may in turn promote the block extrusion under Tibet that has been observed in GPS measurements; hot asthenospheric upwellings may also lead to widespread post-collisional magmatism in southern Tibet.
基金supported by the National Natural Science Foundation of China(61775004,61935016)the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support.
文摘With great achievements in efficiency,stability,and large-scale preparation of perovskite solar cells(PSCs),the com-mercialization of PSC is ongoing,but there is still an issue on lead toxicity.Although lead content in the device is low,the water solubility of lead salts leads to potential environmental pollution.At present,the non-lead perovskites studied in-clude:divalent metal perovskite(e.g.,Sn^(2+),Ge^(2+),Cu^(2+)),trivalent metal perovskite(e.g.,Bi^(3+),Sb^(3+),In^(3+)),tetravalent met-al double perovskite(e.g.,Sn^(4+),Pd^(4+),Ti^(4+),Pt^(4+))and mono-trivalent mixed double perovskite(e.g.,Ag+and Bi^(3+),Ag+and In^(3+),Ag^(+)and Sb^(3+)).Their properties are summarized in Table 1.Since the first report on non-lead double perovskite Cs2AgBiBr6 in 2016^([1]).
文摘On the process of power system black start after an accident, it can help to optimize the resources allocation and accelerate the recovery process that decomposing the power system into several independent partitions for parallel recovery. On the basis of adequate consideration of fuzziness of black-start zone partitioning, a new algorithm based on fuzzy clustering analysis is presented. Characteristic indexes are extracted fully and accurately. The raw data matrix is made up of the electrical distance between every nodes and blackstart resources. Closure transfer method is utilized to get the dynamic clustering. The availability and feasibility of the proposed algorithm are verified on the New-England 39 bus system at last.
基金This work is supported by Open Fund of Hubei Provincial Key Laboratory for Operation and Control of Cascaded Hydropower Station(2019KJX10)Open Fund of Key Laboratory of Tsinghua University(SKLD17KM07).
文摘Among the end-users of the power grid,especially in the rural power grid,there are a large number of users and the situation is complex.In this complex situation,there are more leakage caused by insulation damage and a small number of users stealing electricity.Maintenance staff will take a long time to determine the location of the abnormal user meter box.In view of this situation,themethod of subjective fuzzy clustering and quartile difference is adopted to determine the partition threshold.The power consumption data of end-users are divided into three regions:high,normal and low,which can be used to screen users in the area of abnormal power consumption.Then the trend judgment method is used to further accurately screen to improve the accuracy and reduce the number of users in the abnormal range.Finally according to abnormal power consumption auxiliary locate abnormal electricity users list box.Then the simulation environment is set to verify the application of membership fuzzy clustering and trend judgment in power consumption data partition.
文摘Lyrics retrieval is one of the frequently-used retrieval functions of search engines. However, diversified information requirements are neglected in the existing lyrics retrieval systems. A lyrics retrieval system named LRC Sousou, in which erroneous characters are corrected automatically, the mixed queries of Chinese words and Pinyin are supported, and English phonemes queries are also achieved effectively, is introduced in this paper. The technologies of natural language processing, information retrieval and machine learning algorithm are applied to our lyrics retrieval system which enhance the practicability and efficiency of lyrics search, and improve user experience.
基金supported by the National Key Research and Development Program of China(No.2022YFA1404800)the National Natural Science Foundation of China(Nos.12074312,12174309,12074313,and 62175200)the Fundamental Research Funds for the Central Universities(No.3102019JC008)。
文摘Based on the transverse-longitudinal mapping of Bessel beams,we propose a simple method to construct a self-similar Bessel-like beam whose transverse profile maintains a stretched form during propagation.Specifically,the propagatingvariant width of this beam can be flexibly predesigned.We experimentally demonstrate three types of self-similar Bessellike beams whose width variations are linear,piecewise,and period functions of propagation distance,respectively.The experimental results match well with the theoretical predictions.We also demonstrate that our approach enables the generation of self-similar higher-order vortex Bessel-like beams.
基金the National Key Research and Development Program of China(2022YFB3803300 and 2023YFE0116800)Beijing Natural Science Foundation(IS23037).
文摘Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constantly being broken and has recently reached 26.1%in the lab,which is comparable to the established photovoltaic technologies such as crystalline silicon,copper indium gallium selenide and cadmium telluride(CdTe)solar cells.Currently,perovskite solar cells are standing at the entrance of industrialization,where huge opportunities and risks coexist.However,towards commercialization,challenges of up-scaling,stability and lead toxicity still remain,the proper handling of which could potentially lead to the widespread adoption of perovskite solar cells as a low-cost and efficient source of renewable energy.This review gives a holistic analysis of the path towards commercialization for perovskite solar cells.A comprehensive overview of the current state-of-the-art level for perovskite solar cells and modules will be introduced first,with respect to the module efficiency,stability and current status of industrialization.We will then discuss the challenges that get in the way of commercialization and the corresponding strategies to address them,involving the upscaling,the stability and the lead toxicity issue.Insights into the future direction of commercialization of perovskite photovoltaics was also provided,including the flexible perovskite cells and modules and perovskite indoor photovoltaics.Finally,the future perspectives towards commercialization are put forward.
基金National Key Research and Development Program of China(2022YFA1404800)National Natural Science Foundation of China(12074312,12174309,12074313)Fundamental Research Funds for the Central Universities(3102019JC008)。
文摘The spin Hall effect of a light beam is essentially a product of circular birefringence but is rarely demonstrated.Here,we provide a scheme for initiating off-axis circular birefringence based on the spin-dependent wave vector bifurcation of Bessel beams via a single liquid crystal Pancharatnam–Berry phase element.The tilted Bessel beam shows a detectable photonic spin Hall effect.By introducing the nonlinear propagation trajectories,the spin Hall effect is greatly enhanced.More surprisingly,the two spin states exactly propagate along the scaled trajectories,enabling flexible control of the spin separation.This phenomenon is also applicable to other Bessel-like beams with nonlinear trajectories,which have been already reported.