In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant attention.Knowledge tracing(KT)plays a pivotal role in this field by pred...In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant attention.Knowledge tracing(KT)plays a pivotal role in this field by predicting students’future performance through the analysis of historical interaction data,thereby assisting educators in evaluating knowledgemastery and tailoring instructional strategies.Traditional knowledge tracingmethods,largely based on Recurrent Neural Networks(RNNs)and Transformer models,primarily focus on capturing long-term interaction patterns in sequential data.However,these models may neglect crucial short-term dynamics and other relevant features.This paper introduces a novel approach to knowledge tracing by leveraging a pure Multilayer Perceptron(MLP)architecture.We proposeMixerKT,a knowledge tracing model based on theHyperMixer framework,which uniquely integrates global and localMixer feature extractors.This architecture enables more effective extraction of both long-terminteraction trends and recent learning behaviors,addressing limitations in currentmodels thatmay overlook these key aspects.Empirical evaluations on twowidely-used datasets,ASSIS Tments2009 and Algebra2005,demonstrate that MixerKT consistently outperforms several state-of-the-art models,including DKT,SAKT,and Separated Self-Attentive Neural Knowledge Tracing(SAINT).Specifically,MixerKT achieves higher prediction accuracy,highlighting its effectiveness in capturing the nuances of learners’knowledge states.These results indicate that our model provides a more comprehensive representation of student learning patterns,enhancing the ability to predict future performance with greater precision.展开更多
Although ray tracing produces high-fidelity, realistic images, it is considered computationally burdensome when implemented on a high rendering rate system. Perception-driven rendering techniques generate images with ...Although ray tracing produces high-fidelity, realistic images, it is considered computationally burdensome when implemented on a high rendering rate system. Perception-driven rendering techniques generate images with minimal noise and distortion that are generally acceptable to the human visual system, thereby reducing rendering costs. In this paper, we introduce a perception-entropy-driven temporal reusing method to accelerate real-time ray tracing. We first build a just noticeable difference(JND) model to represent the uncertainty of ray samples and image space masking effects. Then, we expand the shading gradient through gradient max-pooling and gradient filtering to enlarge the visual receipt field. Finally, we dynamically optimize reusable time segments to improve the accuracy of temporal reusing. Compared with Monte Carlo ray tracing, our algorithm enhances frames per second(fps) by 1.93× to 2.96× at 8 to 16 samples per pixel, significantly accelerating the Monte Carlo ray tracing process while maintaining visual quality.展开更多
The art of polychrome lacquer painting with gold tracing and inlay represents the culmination of traditional Chinese lacquer craftsmanship.It integrates four core techniques-lacquer application,polychrome painting,gol...The art of polychrome lacquer painting with gold tracing and inlay represents the culmination of traditional Chinese lacquer craftsmanship.It integrates four core techniques-lacquer application,polychrome painting,gold tracing,and inlay-embodying the pinnacle of ancient artisan ingenuity.This paper begins by outlining the historical origins,technical characteristics,and cultural significance of this art form.Subsequently,using a Qing Dynasty“Hanging Screen Inlaid with Boxwood and Coral Depicting the Scene of Sudhana Paying Homage to Guanyin,with Polychrome Lacquer Painting and Gold Tracing”as a case study,it offers an in-depth analysis of its craftsmanship,visual elements,thematic narrative,and cultural connotations.The study aims to unveil its artistic value and contemporary relevance as a form of“living cultural heritage.”展开更多
Nonhuman primates are increasingly being used as animal models in neuroscience research.However,efficient neuronal tracing techniques for labeling motor neurons and primary sensory afferents in the monkey spinal cord ...Nonhuman primates are increasingly being used as animal models in neuroscience research.However,efficient neuronal tracing techniques for labeling motor neurons and primary sensory afferents in the monkey spinal cord are lacking.Here,by injecting the cholera toxin B subunit into the sciatic nerve of a rhesus monkey,we successfully labeled the motor neurons and primary sensory afferents in the lumbar and sacralspinal cord.Labeled alpha motor neurons were located in lamina IX of the L6–S1 segments,which innervate both flexors and extensors.The labeled primary sensory afferents were mainly myelinated Aβfibers that terminated mostly in laminae I and II of the L4–L7 segments.Together with the labeled proprioceptive afferents,the primary sensory afferents formed excitatory synapses with multiple types of spinal neurons.In summary,our methods successfully traced neuronal connections in the monkey spinal cord and can be used in spinal cord studies when nonhuman primates are used.展开更多
The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick s...The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma.展开更多
Background:Rabies virus(RABV)-derived neuronal tracing tools are extensively applied in retrograde tracing due to their strict retrograde transsynaptic transfer property and low neurotoxicity.However,the RABV infectio...Background:Rabies virus(RABV)-derived neuronal tracing tools are extensively applied in retrograde tracing due to their strict retrograde transsynaptic transfer property and low neurotoxicity.However,the RABV infection and expression of fluorescence products would be gradually cleared while the infected neurons still survive,a phenomenon known as non-cytolytic immune clearance(NCLIC).This phenomenon introduced the risk of fluorescence loss and led to the omission of a subset of neurons that should be labeled,thereby interfering in the analysis of tracing results.Methods:To compensate for the fluorescence loss problem,in this study,we developed a novel marker footprints(MF)mouse,involving a Cre recombinase-dependent red fluorescent reporter system and systemic expression of glycoprotein(G)and ASLV-A receptor(TVA).Using this mouse model combined with the well-developed RABV-EnvA-ΔG-GFP-Cre viral tool,we developed a novel green-to-red spectral labeling strategy.Results:Neurons in the MF mouse could be co-labeled with green fluorescence from the very quick expression of the viral tool and with red fluorescence from the relatively slow expression of the neuron itself,so neurons undergoing NCLIC with green fluorescence loss could be relabeled red.Furthermore,newly infected neurons could be labeled green and other neurons could be labeled yellow due to the temporal expression difference between the two fluorescent proteins.Conclusions:This is the first polysynaptic retrograde tracing labeling strategy that could label neurons using spectral fluorescence colors with only one injection of the viral tool,enabling its application in recognizing the labeling sequence of neurons in brain regions and enhancing the spatiotemporal resolution of neuronal tracing.展开更多
1 Introduction Dissecting the dynamics of cell statesiscrucial for understanding various biological processes,such as tissue development and tumor drug responses.Recent advancements in single-cell lineage tracing(scLT...1 Introduction Dissecting the dynamics of cell statesiscrucial for understanding various biological processes,such as tissue development and tumor drug responses.Recent advancements in single-cell lineage tracing(scLT)technologies provide effective ways to track single-cell lineages through heritable cellular barcodes,while simultaneously detecting the molecular states of cells by sequencing[1].展开更多
Cell lineage tracing is a key technology for describing the developmental history of individual progenitor cells and assembling them to form a lineage development tree.However,traditional methods have limitations of p...Cell lineage tracing is a key technology for describing the developmental history of individual progenitor cells and assembling them to form a lineage development tree.However,traditional methods have limitations of poor stability and insufficient reso-lution.As an efficient and flexible gene editing tool,CRISPR-Cas9 system has been widely used in biological research.Furthermore,CRISPR-Cas9 gene editing-based tracing methods can introduce fluorescent proteins,reporter genes,or DNA barcodes for high-throughput sequencing,enabling precise lineage analysis,significantly im-proving precision and resolution,and expanding its application range.In this review,we summarize applications of CRISPR-Cas9 system in cell lineage tracing,with special emphasis on its successful applications in traditional model animals(e.g.,zebrafish and mice),large animal models(pigs),and human cells or organoids.We also discussed its potential prospects and challenges in xenotransplantation and regenerative medicine.展开更多
Unraveling the lineage relationships of all descendants from a zygote is fundamental to advancing our understanding of developmental and stem cell biology.However,existing cell barcoding technologies in zebrafish lack...Unraveling the lineage relationships of all descendants from a zygote is fundamental to advancing our understanding of developmental and stem cell biology.However,existing cell barcoding technologies in zebrafish lack the resolution to capture the majority of cell divisions during embryogenesis.A recently developed method,a substitution mutation-aided lineage-tracing system(SMALT),successfully reconstructed high-resolution cell phylogenetic trees for Drosophila melanogaster.Here,we implement the SMALT system in zebrafish,recording a median of 14 substitution mutations on a one-kilobase-pair barcoding sequence for one-day post-fertilization embryos.Leveraging this system,we reconstruct four cell lineage trees for zebrafish fin cells,encompassing both original and regenerated fin.Each tree consists of hundreds of internal nodes with a median bootstrap support of 99%.Analysis of the obtained cell lineage trees reveals that regenerated fin cells mainly originate from cells in the same part of the fins.Through multiple times sampling germ cells from the same individual,we show the stability of the germ cell pool and the early separation of germ cell and somatic cell progenitors.Our system offers the potential for reconstructing high-quality cell phylogenies across diverse tissues,providing valuable insights into development and disease in zebrafish.展开更多
Genetic lineage tracing has been widely employed to investigate cell lineages and fate.However,conventional reporting systems often label the entire cytoplasm,making it challenging to discern cell boundaries.Additiona...Genetic lineage tracing has been widely employed to investigate cell lineages and fate.However,conventional reporting systems often label the entire cytoplasm,making it challenging to discern cell boundaries.Additionally,single Cre-lox P recombination systems have limitations in tracing specific cell populations.This study proposes three reporting systems utilizing Cre,Dre,and Dre+Cre mediated recombination.These systems incorporate td Tomato expression on the cell membrane and Phi YFP expression within the nucleus,allowing for clear observation of the nucleus and membrane.The efficacy of these systems is successfully demonstrated by labeling cardiomyocytes and hepatocytes.The potential for dynamic visualization of the cell membrane is showcased using intravital imaging microscopy or threedimensional imaging.Furthermore,by combining this dual recombinase system with the Pro Tracer system,hepatocyte proliferation is traced with enhanced precision.This reporting system holds significant importance for advancing the understanding of cell fate studies in development,homeostasis,and diseases.展开更多
This paper presents a gradient-descent travel time tomography method for solving the acoustictype velocity model inversion problem.Similarly to the adjoint-state method,the proposed method is based on the Eikonal equa...This paper presents a gradient-descent travel time tomography method for solving the acoustictype velocity model inversion problem.Similarly to the adjoint-state method,the proposed method is based on the Eikonal equation,enabling simultaneous calculation of contributions from all common-source receivers to the gradient.This overcomes the inefficiency inherent in conventional travel time tomography methods,which rely on a two-point ray tracing process.By directly calculating Fréchet derivatives,our method avoids the complex derivation processes associated with the adjoint-state method.The key to calculating the Fréchet derivatives is to calculate a so-called ray-path term.Consequently,compared to the adjoint-state method,the proposed method can explicitly obtain the ray paths,resulting in a more concise and intuitive derivation process.Furthermore,our method retains the benefits of the adjoint-state method,such as speed,low memory usage,and robustness.This paper focuses on elucidating the principles and algorithms for calculating the raypath term based on the fast sweeping method.The algorithms could be further speeded up by using parallel computational techniques.Synthetic tests demonstrate that our proposed travel time tomographic method accurately calculates ray paths,regardless of the complexity of the model and recording geometry.展开更多
An advanced method for rapidly computing holograms of large three-dimensional(3D)objects combines backward ray tracing with adaptive resolution wavefront recording plane(WRP)and adaptive angular spectrum propagation.I...An advanced method for rapidly computing holograms of large three-dimensional(3D)objects combines backward ray tracing with adaptive resolution wavefront recording plane(WRP)and adaptive angular spectrum propagation.In the initial phase,a WRP with adjustable resolution and sampling interval based on the object’s size is defined to capture detailed information from large 3D objects.The second phase employs an adaptive angular spectrum method(ASM)to efficiently compute the propagation from the large-sized WRP to the small-sized computer-generated hologram(CGH).The computation process is accelerated using CUDA and OptiX.Optical experiments confirm that the algorithm can generate high-quality holograms with shadow and occlusion effects at a resolution of 1024×1024 in 29 ms.展开更多
Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calcula...Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture.展开更多
To address the problem of subdividing inflexible rectangular grid models and their poor definition of velocity interfaces,we propose a complex structure triangular net for a minimum traveltime ray tracing global algor...To address the problem of subdividing inflexible rectangular grid models and their poor definition of velocity interfaces,we propose a complex structure triangular net for a minimum traveltime ray tracing global algorithm.Our procedure is：（1） Subdivide a triangle grid based on the Delaunay triangular subdivision criterion and the relationships of the points,lines,and the surfaces in the subdividing area.（2） Define the topology relationships and related concepts of triangular unit ray tracing.（3） The source point and wave arrival points at any time compose the propagating plane wave and the minimum traveltime and secondary source positions are calculated during the plane wave propagation.We adopt the hyperbolic approximation global algorithm for secondary source retrieving.（4） By minimum traveltime ray tracing,collect the path from receiver to source points with the neighborhood point＇s traveltime and the direction of the secondary source.Numerical simulation examples are given to test the algorithm.The results show that the triangular net ray tracing method demonstrates model subdivision flexibility,precise velocity discontinuity interfaces,and accurate computations.展开更多
To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions tha...To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.展开更多
Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate ...Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate and introduced a multiplex-feature analysis strategy based on the coffee ring effect.This substrate not only offers high Raman enhancement but also exhibits a high probability of detection(POD),enabling rapid and accurate identification of 50 nm polystyrene nanoplastics over a broad concentration range(1–10−10 wt%).Importantly,experimental results reveal a strong correlation between the coffee ring formation and the concentration of nanoplastic dispersion.By incorporating Raman signal intensity,coffee ring diameter,and POD as combined features,we established a machine learning-based mapping between nanoplastic concentration and coffee ring characteristics,allowing precise predictions of dispersion concentration.The mean squared error of these predictions is remarkably low,ranging from 0.21 to 0.54,representing a 19 fold improvement in accuracy compared to traditional linear regression-based methods.This strategy effectively integrates SERS with wettability modification techniques,ensuring high sensitivity and fingerprinting capabilities,while addressing the limitations of Raman signal intensity in accurately reflecting concentration changes at ultra-low levels,providing a new idea for precise SERS measurements of nanoplastics.展开更多
Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry.In iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of meth...Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry.In iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of methyl iodide and humidity interference are two major issues of the vacuum ultraviolet(VUV)lamp initiated CIMS for on-line gaseous formic and acetic acids analysis.In this work,we present a new CIMS based on VUV lamp,and the ion-molecular reactor is separated into photoionization and chemical ionization zones by a reducer electrode.Acetone was added to the photoionization zone,and the VUV photoionization acetone provided low-energy electrons for methyl iodide to generate I−,and the addition of acetone reduced the amount of methyl iodide by 2/3.In the chemical ionization zone,a headspace vial containing ultrapure water was added for humidity calibration,and the vial changes the sensitivity as a function of humidity from ambiguity to well linear correlation(R2>0.95).With humidity calibration,the CIMS can quantitatively measure formic and acetic acids in the humidity range of 0%-88%RH.In this mode,limits of detection of 10 and 50 pptv are obtained for formic and acetic acids,respectively.And the relative standard deviation(RSD)of quantitation stability for 6 days were less than 10.5%.This CIMS was successfully used to determine the formic and acetic acids in the underground parking and ambient environment of the Shandong University campus(Qingdao,China).In addition,we developed a simple model based formic acid concentration to assess vehicular emissions.展开更多
The technology for green and macro-conversion of solid waste biomass to prepare high-quality activated carbon demands urgent development.This study proposes a technique for synthesizing carbon adsorbents using trace K...The technology for green and macro-conversion of solid waste biomass to prepare high-quality activated carbon demands urgent development.This study proposes a technique for synthesizing carbon adsorbents using trace KOH-catalyzed CO_(2) activation.Comprehensive investigations were conducted on three aspects:physicochemical structure evolution of biochar,mechanistic understanding of trace KOH-facilitated CO_(2) activation processes,and application characteristics for CO_(2) adsorption.Results demonstrate that biochar activated by trace KOH(<10%)and CO_(2) achieves comparable specific surface area(1244.09 m^(2)/g)to that obtained with 100%KOH activation(1425.10 m^(2)/g).The pore structure characteristics(specific surface area and pore volume)are governed by CO and CH4 generated through K-salt catalyzed reactions between CO_(2) and biochar.The optimal CO_(2) adsorption capacities of KBC adsorbent reached 4.70 mmol/g(0℃)and 7.25 mmol/g(25℃),representing the maximum values among comparable carbon adsorbents.The 5%KBC-CO_(2) sample exhibited CO_(2) adsorption capacities of 3.19 and 5.01 mmol/g under respective conditions,attaining current average performance levels.Notably,CO_(2)/N_(2) selectivity(85∶15,volume ratio)reached 64.71 at 0.02 bar with robust cycling stability.Molecular dynamics simulations revealed that oxygen-containing functional groups accelerate CO_(2) adsorption kinetics and enhance micropore storage capacity.This technical route offers simplicity,environmental compatibility,and scalability,providing critical references for large-scale preparation of high-quality carbon materials.展开更多
A fast algorithm for ray tracing is presented, with which the specular reflection term of global illumination model is improved. A hybrid technique combining hierarchical bounding volumes and constant size box partiti...A fast algorithm for ray tracing is presented, with which the specular reflection term of global illumination model is improved. A hybrid technique combining hierarchical bounding volumes and constant size box partitioning is presented and a fast box traversal algorithm is used. By this technique multiple ray intersections with objects that are in more than one box can be avoided. As a result, the speed of ray tracing is considerably increased.展开更多
Anaerobic ammonium oxidation coupled to iron(III)reduction(Feammox)process has recently been recognized as an important pathway for removing ammonium in various natural habitats.However,our understanding for Feammox i...Anaerobic ammonium oxidation coupled to iron(III)reduction(Feammox)process has recently been recognized as an important pathway for removing ammonium in various natural habitats.However,our understanding for Feammox in river–estuary continuum is limited.In this study,stable isotope tracers and high-throughput amplicon sequencing were employed to determine Feammox rates and identify associated microbial communities in sediments along the Yangtze river–estuary continuum.Feammox rates averaged 0.0058±0.0069 mg N/(kg·d)and accounted for approximately 22.3%of the ammonium removed from the sediments.Sediment Fe(III),ammonium(NH_(4)^(+)),total organic carbon(TOC),and pH were identified as important factors influencing Feammox rates.Additionally,Spirochaeta,Caldilineaceae_uncultured,and Ignavibacterium were found potentially associated with Feammox,which had not been documented as Feammox-associated microbial taxa previously.This study demonstrates that Feammox plays a vital role in ammonium removal within the Yangtze river–estuary continuum,providing greater insight into nitrogen removal and cycling in aquatic ecosystems.展开更多
基金supported by National Natural Science Foundation of China(Nos.62266054 and 62166050)Key Program of Fundamental Research Project of Yunnan Science and Technology Plan(No.202201AS070021)+2 种基金Yunnan Fundamental Research Projects(No.202401AT070122)Yunnan International Joint Research and Development Center of China-Laos-Thailand Educational Digitalization(No.202203AP140006)Scientific Research Foundation of Yunnan Provincial Department of Education(No.2024Y159).
文摘In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant attention.Knowledge tracing(KT)plays a pivotal role in this field by predicting students’future performance through the analysis of historical interaction data,thereby assisting educators in evaluating knowledgemastery and tailoring instructional strategies.Traditional knowledge tracingmethods,largely based on Recurrent Neural Networks(RNNs)and Transformer models,primarily focus on capturing long-term interaction patterns in sequential data.However,these models may neglect crucial short-term dynamics and other relevant features.This paper introduces a novel approach to knowledge tracing by leveraging a pure Multilayer Perceptron(MLP)architecture.We proposeMixerKT,a knowledge tracing model based on theHyperMixer framework,which uniquely integrates global and localMixer feature extractors.This architecture enables more effective extraction of both long-terminteraction trends and recent learning behaviors,addressing limitations in currentmodels thatmay overlook these key aspects.Empirical evaluations on twowidely-used datasets,ASSIS Tments2009 and Algebra2005,demonstrate that MixerKT consistently outperforms several state-of-the-art models,including DKT,SAKT,and Separated Self-Attentive Neural Knowledge Tracing(SAINT).Specifically,MixerKT achieves higher prediction accuracy,highlighting its effectiveness in capturing the nuances of learners’knowledge states.These results indicate that our model provides a more comprehensive representation of student learning patterns,enhancing the ability to predict future performance with greater precision.
基金supported by the National Natural Science Foundation of China (No.U19A2063)the Jilin Provincial Science&Technology Development Program of China (No.20230201080GX)。
文摘Although ray tracing produces high-fidelity, realistic images, it is considered computationally burdensome when implemented on a high rendering rate system. Perception-driven rendering techniques generate images with minimal noise and distortion that are generally acceptable to the human visual system, thereby reducing rendering costs. In this paper, we introduce a perception-entropy-driven temporal reusing method to accelerate real-time ray tracing. We first build a just noticeable difference(JND) model to represent the uncertainty of ray samples and image space masking effects. Then, we expand the shading gradient through gradient max-pooling and gradient filtering to enlarge the visual receipt field. Finally, we dynamically optimize reusable time segments to improve the accuracy of temporal reusing. Compared with Monte Carlo ray tracing, our algorithm enhances frames per second(fps) by 1.93× to 2.96× at 8 to 16 samples per pixel, significantly accelerating the Monte Carlo ray tracing process while maintaining visual quality.
文摘The art of polychrome lacquer painting with gold tracing and inlay represents the culmination of traditional Chinese lacquer craftsmanship.It integrates four core techniques-lacquer application,polychrome painting,gold tracing,and inlay-embodying the pinnacle of ancient artisan ingenuity.This paper begins by outlining the historical origins,technical characteristics,and cultural significance of this art form.Subsequently,using a Qing Dynasty“Hanging Screen Inlaid with Boxwood and Coral Depicting the Scene of Sudhana Paying Homage to Guanyin,with Polychrome Lacquer Painting and Gold Tracing”as a case study,it offers an in-depth analysis of its craftsmanship,visual elements,thematic narrative,and cultural connotations.The study aims to unveil its artistic value and contemporary relevance as a form of“living cultural heritage.”
基金supported by a grant from Ministry of Science and Technology China,No.2022ZD0204704(to WW)the National Natural Science Foundation of China,No.82301572(to XZ)the China Postdoctoral Science Foundation,No.2023M731202(to XZ)。
文摘Nonhuman primates are increasingly being used as animal models in neuroscience research.However,efficient neuronal tracing techniques for labeling motor neurons and primary sensory afferents in the monkey spinal cord are lacking.Here,by injecting the cholera toxin B subunit into the sciatic nerve of a rhesus monkey,we successfully labeled the motor neurons and primary sensory afferents in the lumbar and sacralspinal cord.Labeled alpha motor neurons were located in lamina IX of the L6–S1 segments,which innervate both flexors and extensors.The labeled primary sensory afferents were mainly myelinated Aβfibers that terminated mostly in laminae I and II of the L4–L7 segments.Together with the labeled proprioceptive afferents,the primary sensory afferents formed excitatory synapses with multiple types of spinal neurons.In summary,our methods successfully traced neuronal connections in the monkey spinal cord and can be used in spinal cord studies when nonhuman primates are used.
基金C.Lana and F.F.Alkmim benefit from the Brazilian National Research Council(CNPq)research grants 3073353/2019-2 and 311543/2020-0.C.Lana,F.F.Alkmim,and Maria Eugênia Souza are part of the Instituto GeoAtlântico,a National Institute of Science and Technology,CNPq-Brazil process 405653/2022-0We acknowledge Petrobras’s support during the investigation and permission to publish this study.I.Figueiredo acknowledged the Brazilian Federal Agency for Support and Evaluation of Graduate Education(CAPES)for Master's scholarship 88887.816343/2023-00.
文摘The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism,carbonate sedimentation,and deposition of a thick salt layer.The carbonates underlying the salt layer(pre-salt carbonates)were formed in restricted lacustrine basins.Here,the timing and fluid sources of deposition,diagenetic,and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating,87Sr/86Sr,and trace element analyses of samples from the Santos Basin.The very alkaline nature of the Aptian lake(s)produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution.Hydrothermalism caused extensive replacement,dissolution,and calcite cementation.REE+Y PAAS-normalised patterns and 87Sr/86Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation,pH,and continental water source,with 2%–10%hydrothermal fluid input.Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations.U-Pb dating indicates that carbonate deposition occurred between 124.8±2.6 Ma and 120.0±1.6 Ma,earlier than previously proposed,followed closely by the circulation of hydrothermal fluids.Replacement and cementation ages range from 120.5±2.4 Ma to 80.4±2.4 Ma.
基金Hubei Natural Science Foundation of China,Grant/Award Number:2024AFB593。
文摘Background:Rabies virus(RABV)-derived neuronal tracing tools are extensively applied in retrograde tracing due to their strict retrograde transsynaptic transfer property and low neurotoxicity.However,the RABV infection and expression of fluorescence products would be gradually cleared while the infected neurons still survive,a phenomenon known as non-cytolytic immune clearance(NCLIC).This phenomenon introduced the risk of fluorescence loss and led to the omission of a subset of neurons that should be labeled,thereby interfering in the analysis of tracing results.Methods:To compensate for the fluorescence loss problem,in this study,we developed a novel marker footprints(MF)mouse,involving a Cre recombinase-dependent red fluorescent reporter system and systemic expression of glycoprotein(G)and ASLV-A receptor(TVA).Using this mouse model combined with the well-developed RABV-EnvA-ΔG-GFP-Cre viral tool,we developed a novel green-to-red spectral labeling strategy.Results:Neurons in the MF mouse could be co-labeled with green fluorescence from the very quick expression of the viral tool and with red fluorescence from the relatively slow expression of the neuron itself,so neurons undergoing NCLIC with green fluorescence loss could be relabeled red.Furthermore,newly infected neurons could be labeled green and other neurons could be labeled yellow due to the temporal expression difference between the two fluorescent proteins.Conclusions:This is the first polysynaptic retrograde tracing labeling strategy that could label neurons using spectral fluorescence colors with only one injection of the viral tool,enabling its application in recognizing the labeling sequence of neurons in brain regions and enhancing the spatiotemporal resolution of neuronal tracing.
基金supported by the National Key Research and Development Program of China(Nos.2020YFA0712403 and 2021YFF1200901)the National Natural Science Foundation of China(NSFC)(Grant Nos.62133006 and 92268104)+1 种基金the Tsinghua University Initiative Scientific Research Program(No.20221080076)the China Postdoctoral Science Foundation(No.2022M721839).
文摘1 Introduction Dissecting the dynamics of cell statesiscrucial for understanding various biological processes,such as tissue development and tumor drug responses.Recent advancements in single-cell lineage tracing(scLT)technologies provide effective ways to track single-cell lineages through heritable cellular barcodes,while simultaneously detecting the molecular states of cells by sequencing[1].
基金supported by Institute of Laboratory Animal Sciences,Chinese Academy of Medical Sciences and Comparative Medicine Center,Peking Union Medical College,Collaborative Innovation Program of the Chinese Academy of Sciences(22SH19)Nonprofit Central Research Institute Fund of Chinese Academy of Medical Sciences(2023-PT180-01).
文摘Cell lineage tracing is a key technology for describing the developmental history of individual progenitor cells and assembling them to form a lineage development tree.However,traditional methods have limitations of poor stability and insufficient reso-lution.As an efficient and flexible gene editing tool,CRISPR-Cas9 system has been widely used in biological research.Furthermore,CRISPR-Cas9 gene editing-based tracing methods can introduce fluorescent proteins,reporter genes,or DNA barcodes for high-throughput sequencing,enabling precise lineage analysis,significantly im-proving precision and resolution,and expanding its application range.In this review,we summarize applications of CRISPR-Cas9 system in cell lineage tracing,with special emphasis on its successful applications in traditional model animals(e.g.,zebrafish and mice),large animal models(pigs),and human cells or organoids.We also discussed its potential prospects and challenges in xenotransplantation and regenerative medicine.
基金supported by the National Key R&D Program of China(2021YFA1302500 and 2021YFA1302501)the National Natural Science Foundation of China(32293190,32293191,31970570,and 32200492).
文摘Unraveling the lineage relationships of all descendants from a zygote is fundamental to advancing our understanding of developmental and stem cell biology.However,existing cell barcoding technologies in zebrafish lack the resolution to capture the majority of cell divisions during embryogenesis.A recently developed method,a substitution mutation-aided lineage-tracing system(SMALT),successfully reconstructed high-resolution cell phylogenetic trees for Drosophila melanogaster.Here,we implement the SMALT system in zebrafish,recording a median of 14 substitution mutations on a one-kilobase-pair barcoding sequence for one-day post-fertilization embryos.Leveraging this system,we reconstruct four cell lineage trees for zebrafish fin cells,encompassing both original and regenerated fin.Each tree consists of hundreds of internal nodes with a median bootstrap support of 99%.Analysis of the obtained cell lineage trees reveals that regenerated fin cells mainly originate from cells in the same part of the fins.Through multiple times sampling germ cells from the same individual,we show the stability of the germ cell pool and the early separation of germ cell and somatic cell progenitors.Our system offers the potential for reconstructing high-quality cell phylogenies across diverse tissues,providing valuable insights into development and disease in zebrafish.
基金supported by the National Key Research&Development Program of China(2021YFA0805100,2023YFA1800700,2019YFA0110403,2019YFA0802000)the National Science Foundation of China(82088101,32370885,92368103,32370897)the Westlake Education Foundation,and the Benyuan Charity Fund,Research Funds of Hangzhou Institute for Advanced Study(2022ZZ01015 and B04006C01600515)。
文摘Genetic lineage tracing has been widely employed to investigate cell lineages and fate.However,conventional reporting systems often label the entire cytoplasm,making it challenging to discern cell boundaries.Additionally,single Cre-lox P recombination systems have limitations in tracing specific cell populations.This study proposes three reporting systems utilizing Cre,Dre,and Dre+Cre mediated recombination.These systems incorporate td Tomato expression on the cell membrane and Phi YFP expression within the nucleus,allowing for clear observation of the nucleus and membrane.The efficacy of these systems is successfully demonstrated by labeling cardiomyocytes and hepatocytes.The potential for dynamic visualization of the cell membrane is showcased using intravital imaging microscopy or threedimensional imaging.Furthermore,by combining this dual recombinase system with the Pro Tracer system,hepatocyte proliferation is traced with enhanced precision.This reporting system holds significant importance for advancing the understanding of cell fate studies in development,homeostasis,and diseases.
基金supported by 14th Five-Year Plan major science and technology projects(no.KJGG2022-0201)。
文摘This paper presents a gradient-descent travel time tomography method for solving the acoustictype velocity model inversion problem.Similarly to the adjoint-state method,the proposed method is based on the Eikonal equation,enabling simultaneous calculation of contributions from all common-source receivers to the gradient.This overcomes the inefficiency inherent in conventional travel time tomography methods,which rely on a two-point ray tracing process.By directly calculating Fréchet derivatives,our method avoids the complex derivation processes associated with the adjoint-state method.The key to calculating the Fréchet derivatives is to calculate a so-called ray-path term.Consequently,compared to the adjoint-state method,the proposed method can explicitly obtain the ray paths,resulting in a more concise and intuitive derivation process.Furthermore,our method retains the benefits of the adjoint-state method,such as speed,low memory usage,and robustness.This paper focuses on elucidating the principles and algorithms for calculating the raypath term based on the fast sweeping method.The algorithms could be further speeded up by using parallel computational techniques.Synthetic tests demonstrate that our proposed travel time tomographic method accurately calculates ray paths,regardless of the complexity of the model and recording geometry.
基金Project supported by the Special Project of Central Government Guiding Local Science and Technology Development in Beijing 2020(Grant No.Z201100004320006).
文摘An advanced method for rapidly computing holograms of large three-dimensional(3D)objects combines backward ray tracing with adaptive resolution wavefront recording plane(WRP)and adaptive angular spectrum propagation.In the initial phase,a WRP with adjustable resolution and sampling interval based on the object’s size is defined to capture detailed information from large 3D objects.The second phase employs an adaptive angular spectrum method(ASM)to efficiently compute the propagation from the large-sized WRP to the small-sized computer-generated hologram(CGH).The computation process is accelerated using CUDA and OptiX.Optical experiments confirm that the algorithm can generate high-quality holograms with shadow and occlusion effects at a resolution of 1024×1024 in 29 ms.
文摘Ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the Ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture.
基金the National Natural Science Foundation of China(Grant Nos.50974081,50774051, 51034003)the Foundation for the Author of National Excellent Doctoral Dissertation of PR China(Grant No.200958)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT0843)the Open Research Fund Program of the State Key Laboratory of Coal Resources and Safe Mining(China University of Mining and Technology, Beijing)(No.2007-07)
文摘To address the problem of subdividing inflexible rectangular grid models and their poor definition of velocity interfaces,we propose a complex structure triangular net for a minimum traveltime ray tracing global algorithm.Our procedure is：（1） Subdivide a triangle grid based on the Delaunay triangular subdivision criterion and the relationships of the points,lines,and the surfaces in the subdividing area.（2） Define the topology relationships and related concepts of triangular unit ray tracing.（3） The source point and wave arrival points at any time compose the propagating plane wave and the minimum traveltime and secondary source positions are calculated during the plane wave propagation.We adopt the hyperbolic approximation global algorithm for secondary source retrieving.（4） By minimum traveltime ray tracing,collect the path from receiver to source points with the neighborhood point＇s traveltime and the direction of the secondary source.Numerical simulation examples are given to test the algorithm.The results show that the triangular net ray tracing method demonstrates model subdivision flexibility,precise velocity discontinuity interfaces,and accurate computations.
基金supported by the Beijing Natural Science Foundation(No.L212029)the National Natural Science Foundation of China(No.62271043).
文摘To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.
基金the National Natural Science Foundation of China(No.12174229 and 22375117)Natural Science Foundation of Shandong Province(No.ZR2022YQ02 and ZR2023MB149)Taishan Scholars Program of Shandong Province(No.tsqn202306152)for financial support.
文摘Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate and introduced a multiplex-feature analysis strategy based on the coffee ring effect.This substrate not only offers high Raman enhancement but also exhibits a high probability of detection(POD),enabling rapid and accurate identification of 50 nm polystyrene nanoplastics over a broad concentration range(1–10−10 wt%).Importantly,experimental results reveal a strong correlation between the coffee ring formation and the concentration of nanoplastic dispersion.By incorporating Raman signal intensity,coffee ring diameter,and POD as combined features,we established a machine learning-based mapping between nanoplastic concentration and coffee ring characteristics,allowing precise predictions of dispersion concentration.The mean squared error of these predictions is remarkably low,ranging from 0.21 to 0.54,representing a 19 fold improvement in accuracy compared to traditional linear regression-based methods.This strategy effectively integrates SERS with wettability modification techniques,ensuring high sensitivity and fingerprinting capabilities,while addressing the limitations of Raman signal intensity in accurately reflecting concentration changes at ultra-low levels,providing a new idea for precise SERS measurements of nanoplastics.
基金supported by the National Special Fund for the Development of Major Research Equipment and Instrument(No.2020YFF01014503)the Young Taishan Scholars(No.tsqn201909039)the College 20 Project fromJi Nan Science&Technology Bureau(No.2021GXRC058).
文摘Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry.In iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of methyl iodide and humidity interference are two major issues of the vacuum ultraviolet(VUV)lamp initiated CIMS for on-line gaseous formic and acetic acids analysis.In this work,we present a new CIMS based on VUV lamp,and the ion-molecular reactor is separated into photoionization and chemical ionization zones by a reducer electrode.Acetone was added to the photoionization zone,and the VUV photoionization acetone provided low-energy electrons for methyl iodide to generate I−,and the addition of acetone reduced the amount of methyl iodide by 2/3.In the chemical ionization zone,a headspace vial containing ultrapure water was added for humidity calibration,and the vial changes the sensitivity as a function of humidity from ambiguity to well linear correlation(R2>0.95).With humidity calibration,the CIMS can quantitatively measure formic and acetic acids in the humidity range of 0%-88%RH.In this mode,limits of detection of 10 and 50 pptv are obtained for formic and acetic acids,respectively.And the relative standard deviation(RSD)of quantitation stability for 6 days were less than 10.5%.This CIMS was successfully used to determine the formic and acetic acids in the underground parking and ambient environment of the Shandong University campus(Qingdao,China).In addition,we developed a simple model based formic acid concentration to assess vehicular emissions.
基金supported by the National Natural Science Foundation of China(52376103,542B2081).
文摘The technology for green and macro-conversion of solid waste biomass to prepare high-quality activated carbon demands urgent development.This study proposes a technique for synthesizing carbon adsorbents using trace KOH-catalyzed CO_(2) activation.Comprehensive investigations were conducted on three aspects:physicochemical structure evolution of biochar,mechanistic understanding of trace KOH-facilitated CO_(2) activation processes,and application characteristics for CO_(2) adsorption.Results demonstrate that biochar activated by trace KOH(<10%)and CO_(2) achieves comparable specific surface area(1244.09 m^(2)/g)to that obtained with 100%KOH activation(1425.10 m^(2)/g).The pore structure characteristics(specific surface area and pore volume)are governed by CO and CH4 generated through K-salt catalyzed reactions between CO_(2) and biochar.The optimal CO_(2) adsorption capacities of KBC adsorbent reached 4.70 mmol/g(0℃)and 7.25 mmol/g(25℃),representing the maximum values among comparable carbon adsorbents.The 5%KBC-CO_(2) sample exhibited CO_(2) adsorption capacities of 3.19 and 5.01 mmol/g under respective conditions,attaining current average performance levels.Notably,CO_(2)/N_(2) selectivity(85∶15,volume ratio)reached 64.71 at 0.02 bar with robust cycling stability.Molecular dynamics simulations revealed that oxygen-containing functional groups accelerate CO_(2) adsorption kinetics and enhance micropore storage capacity.This technical route offers simplicity,environmental compatibility,and scalability,providing critical references for large-scale preparation of high-quality carbon materials.
文摘A fast algorithm for ray tracing is presented, with which the specular reflection term of global illumination model is improved. A hybrid technique combining hierarchical bounding volumes and constant size box partitioning is presented and a fast box traversal algorithm is used. By this technique multiple ray intersections with objects that are in more than one box can be avoided. As a result, the speed of ray tracing is considerably increased.
基金supported by the National Natural Science Foundation of China(Nos.U2040201,32201334,92251304,and 42271126),the Project of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou,No.GML20220017),the Outstanding Postdoctoral Project in Jiangsu Province(No.2022ZB455),the Chinese Postdoctoral Science Foundation(No.2022M721661)and the Project of State Key Laboratory of Lake Science and Environment(No.2022SKL019).
文摘Anaerobic ammonium oxidation coupled to iron(III)reduction(Feammox)process has recently been recognized as an important pathway for removing ammonium in various natural habitats.However,our understanding for Feammox in river–estuary continuum is limited.In this study,stable isotope tracers and high-throughput amplicon sequencing were employed to determine Feammox rates and identify associated microbial communities in sediments along the Yangtze river–estuary continuum.Feammox rates averaged 0.0058±0.0069 mg N/(kg·d)and accounted for approximately 22.3%of the ammonium removed from the sediments.Sediment Fe(III),ammonium(NH_(4)^(+)),total organic carbon(TOC),and pH were identified as important factors influencing Feammox rates.Additionally,Spirochaeta,Caldilineaceae_uncultured,and Ignavibacterium were found potentially associated with Feammox,which had not been documented as Feammox-associated microbial taxa previously.This study demonstrates that Feammox plays a vital role in ammonium removal within the Yangtze river–estuary continuum,providing greater insight into nitrogen removal and cycling in aquatic ecosystems.
