Moist-electric generation,a green and environmentally friendly energy harvesting technology,is undoubt-edly one of the effective methods to alleviate energy shortages and environmental damage.However,the lack of fiber...Moist-electric generation,a green and environmentally friendly energy harvesting technology,is undoubt-edly one of the effective methods to alleviate energy shortages and environmental damage.However,the lack of fiber-like moist-electric generators(MEGs)that combine continuous power generation and high electrical output performance has constrained the development of moist-electric in the fields of flexi-ble wearable and self-power supplies.In this work,sodium alginate(SA)/multi-walled carbon nanotubes(MWCNT)fibers with axial heterogeneous(axi-he)of oxygen-containing functional groups(Ocfgs)are prepared through a mold forming method in assistance with the coagulation process.The interaction be-tween axi-he MEG and moisture is investigated by analyzing the electrical signal changes of dried MEG under moisture stimulation.The maximum output voltage and current of axi-he MEG can reach 0.35 V and 1.92μA under the stimulation of moisture.Based on the regulation of Ocfgs,axi-he MEG has a con-tinuous high moist-electric performance and environmental adaptability.The maximum output power density(Pmo)of axi-he MEG with a length of only 2 cm can reach 27.37μW cm-2 at RH=90%,which exceeds most of the MEGs reported in literature.Meanwhile,a continuous output voltage of 0.33-0.37 V for more than 15 h can be obtained from this axi-he MEG.Thus,the axi-he MEG from Ocfg distribution design and mold forming method provides a new way of clean energy generation using moisture from the ambient environment,exhibiting enormous potential in energy supply for Internet of Things(IoT)devices.展开更多
Intellectual disability(ID)is a condition characterized by cognitive impairment and difficulties in adaptive functioning.In our research,we identified two de novo mutations(c.955C>T and c.732C>A)at the KDM2A loc...Intellectual disability(ID)is a condition characterized by cognitive impairment and difficulties in adaptive functioning.In our research,we identified two de novo mutations(c.955C>T and c.732C>A)at the KDM2A locus in individuals with varying degrees of ID.In addition,by using the Gene4Denovo database,we discovered five additional cases of de novo mutations in KDM2A.The mutations we identified significantly decreased the expression of the KDM2A protein.To investigate the role of KDM2A in neural development,we used both 2D neural stem cell models and 3D cerebral organoids.Our findings demonstrated that the reduced expression of KDM2A impairs the proliferation of neural progenitor cells(NPCs),increases apoptosis,induces premature neuronal differentiation,and affects synapse maturation.Through ChIP-Seq analysis,we found that KDM2A exhibited binding to the transcription start site regions of genes involved in neurogenesis.In addition,the knockdown of KDM2A hindered H3K36me2 binding to the downstream regulatory elements of genes.By integrating ChIP-Seq and RNA-Seq data,we made a significant discovery of the core genes'remarkable enrichment in the MAPK signaling pathway.Importantly,this enrichment was specifically linked to the p38 MAPK pathway.Furthermore,disease enrichment analysis linked the differentially-expressed genes identified from RNA-Seq of NPCs and cerebral organoids to neurodevelopmental disorders such as ID,autism spectrum disorder,and schizophrenia.Overall,our findings suggest that KDM2A plays a crucial role in regulating the H3K36me2 modification of downstream genes,thereby modulating the MAPK signaling pathway and potentially impacting early brain development.展开更多
Curation in museums involves not only presenting exhibits for visitors but also deeply shaping a systematic narrative experience through deliberate spatial layout design of the museum space.In contrast,the dynamic nat...Curation in museums involves not only presenting exhibits for visitors but also deeply shaping a systematic narrative experience through deliberate spatial layout design of the museum space.In contrast,the dynamic nature of virtual reality(VR)environments establishes virtual museums as a more potent space for both layout optimization and narrative construction,particularly when integrating visitors’diverse preferences to optimize the virtual museum and convey narratives.Therefore,we first collaborated with experienced curators to conduct a formative study to understand the workflow of curation and summarize the museum narratives that weave exhibits,galleries,and museum architecture into a compelling story.We then proposed a museum spatial layout framework that clarified three narrative levels(exhibit level,gallery level,and architecture level)to support the controllable spatial layout of the museum’s elements.Based on that,we developed VirtuNarrator,a proof-of-concept prototype designed to assist visitors in choosing different narrative themes,filtering exhibits,creating and adjusting galleries,and freely connecting them.The evaluation results validated that visitors received a more systematic museum narrative experience and perceptions of multi-perspective narrative design in VirtuNarrator.We also provided insights into VR-based museum narrative enhancement beyond spatial layout design.展开更多
A 17-year-old girl from Shannan,Xizang,a region located at an altitude of approximately 3,600 meters,presented with a two-month history of intermittent abdominal pain predominantly in the epigastric and right lower qu...A 17-year-old girl from Shannan,Xizang,a region located at an altitude of approximately 3,600 meters,presented with a two-month history of intermittent abdominal pain predominantly in the epigastric and right lower quadrant regions.The pain was exacerbated by food intake and was occasionally accompanied by episodes of bile-stained vomiting.There was no history of alcohol use,abdominal trauma,or changes in bowel habits.Her medical history was notable for Graves’disease,for which she had been receiving methimazole and propranolol.展开更多
Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the ...Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.展开更多
The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation detect...The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation detectors.The background subtraction,normalization,and correction were carefully considered in the data analysis to obtain accurate cross sections.For the resonance at 3.9 eV,the R-matrix code SAMMY was used to determine the resonance parameters with the internal normalization method.The average capture cross sections of ^(169)Tm for energy between 30 and 300 keV were extracted relative to the ^(197)Au(n,γ)reaction.The measured cross sections of the ^(169)Tm(n,γ)reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this study and described in terms of average resonance parameters using a Hauser-Feshbach calculation with fluctuations.The point-wise cross sections and the average resonance parameters showed fair agreement with the evaluated values of the ENDF/B-Ⅷ.0 library in the energy region studied.展开更多
The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential c...The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential cross-sections of the^6 Li(n,t)~4 He reaction at 15 detection angles ranging from 19.2°to 160.8°are obtained from 1.0 eV to 3.0 MeV at 80 neutron energy points;for 50 energy points below 0.1 MeV they are reported for the first time.The results indicate that the anisotropy of the emitted tritium is noticeable above E_n=100 eV.The angle-integrated cross-sections are also obtained.The present differential cross-sections agree in general with the previous evaluations,but there are some differences in the details.More importantly,the present results indicate that the cross-sections of the^6 Li(n,t)~4 He reaction might be overestimated by most evaluations in the 0.5-3.0 MeV region,although they are recommended as standards below 1.0 MeV.展开更多
The neutron-induced total cross-section of ^(209)Bi is crucial for the physical design and safety assessment of lead-based fast reactors, and the quality of experimental data should be improved for evaluation and appl...The neutron-induced total cross-section of ^(209)Bi is crucial for the physical design and safety assessment of lead-based fast reactors, and the quality of experimental data should be improved for evaluation and application.A recent experiment was conducted on the back-streaming white neutron beamline(Back-n) at the China Spallation Neutron Source(CSNS) using the neutron total cross-section spectrometer(NTOX). The neutron energy was determined using a fast multi-cell fission chamber and the time-of-flight technique. Two high-purity bismuth samples,6 mm and 20 mm in thickness, were chosen for neutron transmission measurements and comparisons. The neutron total cross-sections of ^(209)Bi, ranging from 0.3 e V to 20 Me V, were derived considering neutron flight time determination, flight path calibration, and background subtraction. A comparison of the experimental results with the data in the ENDF/B-VⅢ.0 library showed fair agreement, and the point-wise cross-sections were found to be consistent with existing experimental data. Special attention was given to the determination of resonance parameters, which were analyzed using the R-matrix code SAMMY and Bayesian method in the 0.5 ke V to 20 ke V energy range. The extracted resonance parameters were compared to previously reported results and evaluated data. This study is recognized as the first one where the neutron total cross-section of bismuth across such a broad energy spectrum is measured in a single measurement or experiment, and it provides valuable data for the assessment of related reaction information for evaluated libraries and the advancement of lead-bismuth-based nuclear systems.展开更多
Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diam...Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diameter and^85.0μg/cm^2 in thickness each with an aluminum backing were prepared,and back-to-back mounted at the sample holder.The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array(LPDA)system.The neutron energy En was determined by TOF(time-of-flight)method,and the valid a events were extracted from the En-Amplitude two-dimensional spectrum.With 15 silicon detectors,the differential cross sections of a-particles were measured from 19.2°to 160.8°.Fitted with the Legendre polynomial series,the(n,a)cross sections were obtained through integration.The absolute cross sections were normalized using the standard cross sections of the 10B(n,α)^7 Li reaction in the 0.3-0.5 MeV neutron energy region.The measurement neutron energy range for the 10B(n,α)^7 Li reaction is 1.0 eV≤En<2.5 Me V(67 energy points),and that for the 10B(n,α0)^7 Li and10B(n,α1)^7 Li^*reactions is 1.0 eV≤En<1.0 MeV(59 energy points).The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system,and compared with existing measurements and evaluations.展开更多
The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy...The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy region has been measured using time-of-flight and transmission methods with the Neutron Total Cross Sectional Spectrometer(NTOX)based on the multi-cell fast fission chamber at the China Spallation Neutron Source(CSNS)-Back-n white neutron source(Back-n).The fission count-neutron energy distributions of ^(235)U and ^(238)U without samples and with Be samples with three thicknesses were measured in the double-bunch operation mode for a beam power of 100 kW.The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV.The neutron total cross section of^(9)Be results was consistent with ENDF/B-VIII.0 evaluation library data in the 0.3 eV−20 MeV energy region.In the energy ranges of 0.3 eV to 10 keV and 0.01 to 20 MeV,the deviations between our results and the evaluation results of ENDF/B-VIII.0 were within 2.5%and 15%,respectively.In the resonance energy region,the measured resonance energies in our experiment were 0.63,0.82,and 2.8 MeV,respectively.The results showed that the total cross section uncertainties of three Be samples were within 2.2%in the energy region below 1 MeV.The total cross section uncertainty of 30 mm Be from ^(235)U was the smallest and less than 5%in the energy region of 0.3 eV−120 MeV.The results of this experiment can provide technical support for further data analysis and related nuclear data evaluation.展开更多
Based on a log-structured merge(LSM)tree,the key-value(KV)storage system can provide high reading performance and optimize random writing performance.It is widely used in modern data storage systems like e-commerce,on...Based on a log-structured merge(LSM)tree,the key-value(KV)storage system can provide high reading performance and optimize random writing performance.It is widely used in modern data storage systems like e-commerce,online analytics,and real-time communication.An LSM tree stores new KV data in the memory and flushes to disk in batches.To prevent data loss in memory if there is an unexpected crash,RocksDB appends updating data in the write-ahead log(WAL)before updating the memory.However,synchronous WAL significantly reduces writing performance.In this paper,we present a new WAL mechanism named MyWAL.It directly manages raw devices(or partitions)instead of saving data on a traditional file system.These can avoid useless metadata updating and write data sequentially on disks.Experimental results show that MyWAL can significantly improve the data writing performance of RocksDB compared to the traditional WAL for small KV data on solid-state disks(SSDs),as much as five to eight times faster.On non-volatile memory express soild-state drives(NVMe SSDs)and non-volatile memory(NVM),MyWAL can improve data writing performance by 10%–30%.Furthermore,the results of YCSB(Yahoo!Cloud Serving Benchmark)show that the latency decreased by 50%compared with SpanDB.展开更多
The Back-n white neutron source(known as Back-n)is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source(CSNS).With its excellent beam properties,e.g.,a neutron flux of app...The Back-n white neutron source(known as Back-n)is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source(CSNS).With its excellent beam properties,e.g.,a neutron flux of approximately 1.8×107 n/cm2/s at 55 m from the spallation target,energy range spanning from 0.5 eV to 200 MeV,and time-of-flight resolution of a few per thousand,along with the equipped physical spectrometers,Back-n is considered to be among the best facilities in the world for carrying out nuclear data measurements.Since its completion and commencement of operation in May 2018,five types of cross-section measurements concerning neutron capture cross-sections,fission cross-sections,total cross-sections,light charged particle emissions,in-beam gamma spectra,and more than forty nuclides have been measured.This article presents an overview of the experimental setup and result analysis on the neutron-induced cross-section measurements and gamma spectroscopy at Back-n in the initial years.展开更多
The neutron total cross-section of ^(nat)Cr plays a crucial role in new nuclear engineering design and fundamental science.A new measurement of the neutron-induced total cross-sections of ^(nat)Cr was performed using ...The neutron total cross-section of ^(nat)Cr plays a crucial role in new nuclear engineering design and fundamental science.A new measurement of the neutron-induced total cross-sections of ^(nat)Cr was performed using the transmission method on the back-streaming white neutron beamline(Back-n)at the China Spallation Neutron Source(CSNS).The neutron energy was determined using the time-of-flight technique.The neutron total cross-sections of ^(nat)Cr were obtained across a broad energy range(0.3 eV−20 MeV)in one experiment for the first time.The resulting effective total cross-sections were compared with the existing experimental data in different energy ranges,which revealed good agreement with the evaluated libraries.Theoretical calculation of the total cross-section in the energy range of 1.5 to 20 MeV was then conducted using TALYS-1.96 and compared with the present results.The measurement provides a high-quality total cross-section of ^(nat)Cr,including detailed uncertainty data across a wide energy range,offering a valuable reference for nuclear data re-evaluation and nuclear engineering design.展开更多
Accurate cross sections of neutron induced fission reactions are required in the design of advanced nuclear systems and the development of fission theory.Time projection chambers(TPCs),with their track reconstruction ...Accurate cross sections of neutron induced fission reactions are required in the design of advanced nuclear systems and the development of fission theory.Time projection chambers(TPCs),with their track reconstruction and particle identification capabilities,are considered the best detectors for high-precision fission cross section measurements.The TPC developed by the back-streaming white neutron source(Back-n)team of the China Spallation Neutron Source(CSNS)was used as the fission fragment detector in measurements.In this study,the cross sections of the ^(232)Th(n,f)reaction at five neutron energies in the 4.50−5.40 MeV region were measured.The fission fragments and α particles were well identified using our TPC,which led to a higher detection efficiency of the fission fragments and smaller uncertainty of the measured cross sections.Ours is the first measurement of the ^(232)Th(n,f)reaction using a TPC for the detection of fission fragments.With uncertainties less than 5%,our cross sections are consistent with the data in different evaluation libraries,including JENDL-4.0,ROSFOND-2010,CENDL-3.2,ENDF/B-VⅢ.0,and BROND-3.1,whose uncertainties can be reduced after future improvement of the measurement.展开更多
The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neut...The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neutron Source(CSNS)Back-n white neutron source.By employing theΔE-E telescopes of the Light-charged Particle Detector Array(LPDA)system at 15.1°to 55.0°in the laboratory system,ratios of the angle-differential cross sections of the ^(12)C(n,xd)reactions to those of the n-p scattering were measured,and then,the angle-differential cross sections of the ^(12)C(n,xd)reactions were obtained using the angle-differential cross sections of the n-p elastic scattering from the JENDL-4.0/HE-2015 library as the standard.The obtained results are compared with data from previous measurements,all of which are based on mono-energic neutrons,the evaluated data from the JENDL-4.0/HE-2015 library and the ENDF-B/VIII.0 library,and those from theoretical calculations based on INCA code and Talys-1.9 code.Being the first white-neutron-source-based systematic measurement of the angle-differential cross sections of neutron-induced deuteron production reactions on carbon in several tens of MeV,the present work can provide a reference to the data library considering the lack of experimental data.展开更多
This study applied a steady-state visual evoked potential(SSVEP)based brain–computer interface(BCI)to a patient in lock-in state with amyotrophic lateral sclerosis(ALS)and validated its feasibility for communication....This study applied a steady-state visual evoked potential(SSVEP)based brain–computer interface(BCI)to a patient in lock-in state with amyotrophic lateral sclerosis(ALS)and validated its feasibility for communication.The developed calibration-free and asynchronous spelling system provided a natural and efficient communication experience for the patient,achieving a maximum free-spelling accuracy above 90%and an information transfer rate of over 22.203 bits/min.A set of standard frequency scanning and task spelling data were also acquired to evaluate the patient’s SSVEP response and to facilitate further personalized BCI design.The results demonstrated that the proposed SSVEP-based BCI system was practical and efficient enough to provide daily life communication for ALS patients.展开更多
Accurate fission cross section data are essential for nuclear science and engineering.Traditional fission cross section measurements using the fission ionization chamber struggle to satisfy the accuracy requirements.T...Accurate fission cross section data are essential for nuclear science and engineering.Traditional fission cross section measurements using the fission ionization chamber struggle to satisfy the accuracy requirements.The Time Projection Chamber(TPC)is a potential detector for high accuracy fission cross section measurement based on its track reconstruction and particle identification capacities.Using the Multi-purpose Time Projection Chamber(MTPC)at the China Spallation Neutron Source(CSNS),we have previously measured the cross sections of the ^(232)Th(n,f)reaction based on the mono-energetic neutron source at Peking University(PKU),showing the potential of high accuracy fission cross section measurement.In this study,cross sections of the ^(235)U(n,f)reaction were measured at 43 energies(10 energy bins per magnitude in equal logarithm intervals)and 215 energies(50 energy bins per magnitude in equal logarithm intervals)in the neutron energy range from 0.5 eV to 10 keV using the MTPC based on the CSNS Back-n white neutron source.The results are consistent with the data in the evaluation libraries,showing the reliability of the fission cross section measurement method using the MTPC.The measurement of the fission cross sections using the MTPC is extended from mono-energetic to white neutron sources.This study presents the first cross section results measured by the MTPC based on the CSNS Back-n white neutron source.With a longer beam time in future measurements,the uncertainties of the fission cross sections are expected to be greatly reduced.展开更多
The neutron total cross section( σ_(t))of^(169)Tm is of considerable importance in the design of nuclear reactors and applications of nuclear technology.However,the σ_(t) of^(169)Tm is unavailable in the 5 keV to 2....The neutron total cross section( σ_(t))of^(169)Tm is of considerable importance in the design of nuclear reactors and applications of nuclear technology.However,the σ_(t) of^(169)Tm is unavailable in the 5 keV to 2.3 MeV energy range in the Experimental Nuclear Reaction Data library and exhibits significant discrepancies among different Evaluated Nuclear Data libraries in the keV region.To clarify the discrepancies in the σ_(t) of^(169)Tm in the keV energy region,we developed a new measurement strategy using the transmission method and the time-of-flight technique and employed it at the back-streaming white neutron beamline of the China Spallation Neutron Source.The experimental background was quantitatively determined using the saturated resonance absorption technique with a 7Li-glass scintillator.The σ_(t) of^(169)Tm in the 1110 keV energy range was obtained,and the value showed good agreement with the evaluated data in the JENDL-5 library.The calculations of the optical model agree well with the results and the fine-tuned optical model parameters in TALYS validated against the 2.32.5 MeV data reported by Foster and Glasgow,with deviations below 5%.The results fill the experimental gap in the 5110 keV range and thus provide valuable input for research on nuclear reactions and evaluations of nuclear data.展开更多
基金supported by the National Natural Science Foundation of China(No.22073015)the National Key R&D Program of China(No.2022YFB3704600).
文摘Moist-electric generation,a green and environmentally friendly energy harvesting technology,is undoubt-edly one of the effective methods to alleviate energy shortages and environmental damage.However,the lack of fiber-like moist-electric generators(MEGs)that combine continuous power generation and high electrical output performance has constrained the development of moist-electric in the fields of flexi-ble wearable and self-power supplies.In this work,sodium alginate(SA)/multi-walled carbon nanotubes(MWCNT)fibers with axial heterogeneous(axi-he)of oxygen-containing functional groups(Ocfgs)are prepared through a mold forming method in assistance with the coagulation process.The interaction be-tween axi-he MEG and moisture is investigated by analyzing the electrical signal changes of dried MEG under moisture stimulation.The maximum output voltage and current of axi-he MEG can reach 0.35 V and 1.92μA under the stimulation of moisture.Based on the regulation of Ocfgs,axi-he MEG has a con-tinuous high moist-electric performance and environmental adaptability.The maximum output power density(Pmo)of axi-he MEG with a length of only 2 cm can reach 27.37μW cm-2 at RH=90%,which exceeds most of the MEGs reported in literature.Meanwhile,a continuous output voltage of 0.33-0.37 V for more than 15 h can be obtained from this axi-he MEG.Thus,the axi-he MEG from Ocfg distribution design and mold forming method provides a new way of clean energy generation using moisture from the ambient environment,exhibiting enormous potential in energy supply for Internet of Things(IoT)devices.
基金supported by the National Natural Science Foundation of China(82022024,31970572,and 31871276)the National Key R&D Project of China(2016YFC1306000 and 2017YFC0908701)+3 种基金the Innovation-driven Project of Central South University(2020CX003)The Natural Science Foundation of Hunan Province(2023JJ40793)NIH grants(U01 MH122591,1U01MH116489,and 1R01MH110920)the Postgraduate Scientific Research Innovation Project of Hunan Province(CX20220320).
文摘Intellectual disability(ID)is a condition characterized by cognitive impairment and difficulties in adaptive functioning.In our research,we identified two de novo mutations(c.955C>T and c.732C>A)at the KDM2A locus in individuals with varying degrees of ID.In addition,by using the Gene4Denovo database,we discovered five additional cases of de novo mutations in KDM2A.The mutations we identified significantly decreased the expression of the KDM2A protein.To investigate the role of KDM2A in neural development,we used both 2D neural stem cell models and 3D cerebral organoids.Our findings demonstrated that the reduced expression of KDM2A impairs the proliferation of neural progenitor cells(NPCs),increases apoptosis,induces premature neuronal differentiation,and affects synapse maturation.Through ChIP-Seq analysis,we found that KDM2A exhibited binding to the transcription start site regions of genes involved in neurogenesis.In addition,the knockdown of KDM2A hindered H3K36me2 binding to the downstream regulatory elements of genes.By integrating ChIP-Seq and RNA-Seq data,we made a significant discovery of the core genes'remarkable enrichment in the MAPK signaling pathway.Importantly,this enrichment was specifically linked to the p38 MAPK pathway.Furthermore,disease enrichment analysis linked the differentially-expressed genes identified from RNA-Seq of NPCs and cerebral organoids to neurodevelopmental disorders such as ID,autism spectrum disorder,and schizophrenia.Overall,our findings suggest that KDM2A plays a crucial role in regulating the H3K36me2 modification of downstream genes,thereby modulating the MAPK signaling pathway and potentially impacting early brain development.
基金supported by the National Social Science Fund of China(No.19ZDA046)the National Natural Science Foundation of China(No.62302440)the Fundamental Research Funds for the Central Universities.
文摘Curation in museums involves not only presenting exhibits for visitors but also deeply shaping a systematic narrative experience through deliberate spatial layout design of the museum space.In contrast,the dynamic nature of virtual reality(VR)environments establishes virtual museums as a more potent space for both layout optimization and narrative construction,particularly when integrating visitors’diverse preferences to optimize the virtual museum and convey narratives.Therefore,we first collaborated with experienced curators to conduct a formative study to understand the workflow of curation and summarize the museum narratives that weave exhibits,galleries,and museum architecture into a compelling story.We then proposed a museum spatial layout framework that clarified three narrative levels(exhibit level,gallery level,and architecture level)to support the controllable spatial layout of the museum’s elements.Based on that,we developed VirtuNarrator,a proof-of-concept prototype designed to assist visitors in choosing different narrative themes,filtering exhibits,creating and adjusting galleries,and freely connecting them.The evaluation results validated that visitors received a more systematic museum narrative experience and perceptions of multi-perspective narrative design in VirtuNarrator.We also provided insights into VR-based museum narrative enhancement beyond spatial layout design.
基金supported by the Natural Science Foundation of Xizang Autonomous Region[grant No.XZZR202402007(W)]Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences(No.2024-RW320-01)+3 种基金National Natural Science Foundation of China(grant Nos.32170788,and 82460135)Beijing Natural Science Foundation(grant Nos.7232123,7244390,and L248074)the National High Level Hospital Clinical Research Funding(grant No.2022-PUMCH-B-023)was also supported by the CAMS Innovation Fund for Medical Sciences(No.2023-I2M-C&T-B-036 to Yonghao Chen and Q.W.).
文摘A 17-year-old girl from Shannan,Xizang,a region located at an altitude of approximately 3,600 meters,presented with a two-month history of intermittent abdominal pain predominantly in the epigastric and right lower quadrant regions.The pain was exacerbated by food intake and was occasionally accompanied by episodes of bile-stained vomiting.There was no history of alcohol use,abdominal trauma,or changes in bowel habits.Her medical history was notable for Graves’disease,for which she had been receiving methimazole and propranolol.
基金the National Natural Science Foundation of China(Grant Nos.11790321 and 11805282)the National Key R&D Program of China(Grant No.2016YFA0401601).
文摘Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.
基金Supported by the National Natural Science Foundation of China(11790321,11805282)the National Key Research and Development Program of China(2016YFA0401601)。
文摘The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation detectors.The background subtraction,normalization,and correction were carefully considered in the data analysis to obtain accurate cross sections.For the resonance at 3.9 eV,the R-matrix code SAMMY was used to determine the resonance parameters with the internal normalization method.The average capture cross sections of ^(169)Tm for energy between 30 and 300 keV were extracted relative to the ^(197)Au(n,γ)reaction.The measured cross sections of the ^(169)Tm(n,γ)reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this study and described in terms of average resonance parameters using a Hauser-Feshbach calculation with fluctuations.The point-wise cross sections and the average resonance parameters showed fair agreement with the evaluated values of the ENDF/B-Ⅷ.0 library in the energy region studied.
基金Supported by National Key R&D Program of China(2016YFA0401604)National Natural Science Foundation of China(11775006)Science and Technology on Nuclear Data Laboratory and China Nuclear Data Center
文摘The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential cross-sections of the^6 Li(n,t)~4 He reaction at 15 detection angles ranging from 19.2°to 160.8°are obtained from 1.0 eV to 3.0 MeV at 80 neutron energy points;for 50 energy points below 0.1 MeV they are reported for the first time.The results indicate that the anisotropy of the emitted tritium is noticeable above E_n=100 eV.The angle-integrated cross-sections are also obtained.The present differential cross-sections agree in general with the previous evaluations,but there are some differences in the details.More importantly,the present results indicate that the cross-sections of the^6 Li(n,t)~4 He reaction might be overestimated by most evaluations in the 0.5-3.0 MeV region,although they are recommended as standards below 1.0 MeV.
基金the National Natural Science Foundation of China(12375296)the Key Laboratory of Nuclear Data Foundation(JCKY2022201C153)+1 种基金the National Key Research and Development Plan(2022YFA1603303)the Natural Science Foundation of Hunan Province of China(2021JJ40444,2020RC3054)。
文摘The neutron-induced total cross-section of ^(209)Bi is crucial for the physical design and safety assessment of lead-based fast reactors, and the quality of experimental data should be improved for evaluation and application.A recent experiment was conducted on the back-streaming white neutron beamline(Back-n) at the China Spallation Neutron Source(CSNS) using the neutron total cross-section spectrometer(NTOX). The neutron energy was determined using a fast multi-cell fission chamber and the time-of-flight technique. Two high-purity bismuth samples,6 mm and 20 mm in thickness, were chosen for neutron transmission measurements and comparisons. The neutron total cross-sections of ^(209)Bi, ranging from 0.3 e V to 20 Me V, were derived considering neutron flight time determination, flight path calibration, and background subtraction. A comparison of the experimental results with the data in the ENDF/B-VⅢ.0 library showed fair agreement, and the point-wise cross-sections were found to be consistent with existing experimental data. Special attention was given to the determination of resonance parameters, which were analyzed using the R-matrix code SAMMY and Bayesian method in the 0.5 ke V to 20 ke V energy range. The extracted resonance parameters were compared to previously reported results and evaluated data. This study is recognized as the first one where the neutron total cross-section of bismuth across such a broad energy spectrum is measured in a single measurement or experiment, and it provides valuable data for the assessment of related reaction information for evaluated libraries and the advancement of lead-bismuth-based nuclear systems.
基金Supported by financially the National Key R&D Program of China(2016YFA0401604)the National Natural Science Foundation of China(11775006)
文摘Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diameter and^85.0μg/cm^2 in thickness each with an aluminum backing were prepared,and back-to-back mounted at the sample holder.The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array(LPDA)system.The neutron energy En was determined by TOF(time-of-flight)method,and the valid a events were extracted from the En-Amplitude two-dimensional spectrum.With 15 silicon detectors,the differential cross sections of a-particles were measured from 19.2°to 160.8°.Fitted with the Legendre polynomial series,the(n,a)cross sections were obtained through integration.The absolute cross sections were normalized using the standard cross sections of the 10B(n,α)^7 Li reaction in the 0.3-0.5 MeV neutron energy region.The measurement neutron energy range for the 10B(n,α)^7 Li reaction is 1.0 eV≤En<2.5 Me V(67 energy points),and that for the 10B(n,α0)^7 Li and10B(n,α1)^7 Li^*reactions is 1.0 eV≤En<1.0 MeV(59 energy points).The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system,and compared with existing measurements and evaluations.
基金Supported by the National Key Research and Development Plan(2016YFA0401603)the National Natural Science Foundation of China(11675155,11790321)Foundation of President of China Academy of Engineering Physics(YZJLX2016003)。
文摘The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy region has been measured using time-of-flight and transmission methods with the Neutron Total Cross Sectional Spectrometer(NTOX)based on the multi-cell fast fission chamber at the China Spallation Neutron Source(CSNS)-Back-n white neutron source(Back-n).The fission count-neutron energy distributions of ^(235)U and ^(238)U without samples and with Be samples with three thicknesses were measured in the double-bunch operation mode for a beam power of 100 kW.The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV.The neutron total cross section of^(9)Be results was consistent with ENDF/B-VIII.0 evaluation library data in the 0.3 eV−20 MeV energy region.In the energy ranges of 0.3 eV to 10 keV and 0.01 to 20 MeV,the deviations between our results and the evaluation results of ENDF/B-VIII.0 were within 2.5%and 15%,respectively.In the resonance energy region,the measured resonance energies in our experiment were 0.63,0.82,and 2.8 MeV,respectively.The results showed that the total cross section uncertainties of three Be samples were within 2.2%in the energy region below 1 MeV.The total cross section uncertainty of 30 mm Be from ^(235)U was the smallest and less than 5%in the energy region of 0.3 eV−120 MeV.The results of this experiment can provide technical support for further data analysis and related nuclear data evaluation.
基金Project supported by the National Key Research and Development Project of China(No.2022YFB2702101)the Shaanxi Province Key Industrial Projects,China(Nos.2021ZDLGY03-02 and 2021ZDLGY03-08)the National Natural Science Foundation of China(No.92152301)。
文摘Based on a log-structured merge(LSM)tree,the key-value(KV)storage system can provide high reading performance and optimize random writing performance.It is widely used in modern data storage systems like e-commerce,online analytics,and real-time communication.An LSM tree stores new KV data in the memory and flushes to disk in batches.To prevent data loss in memory if there is an unexpected crash,RocksDB appends updating data in the write-ahead log(WAL)before updating the memory.However,synchronous WAL significantly reduces writing performance.In this paper,we present a new WAL mechanism named MyWAL.It directly manages raw devices(or partitions)instead of saving data on a traditional file system.These can avoid useless metadata updating and write data sequentially on disks.Experimental results show that MyWAL can significantly improve the data writing performance of RocksDB compared to the traditional WAL for small KV data on solid-state disks(SSDs),as much as five to eight times faster.On non-volatile memory express soild-state drives(NVMe SSDs)and non-volatile memory(NVM),MyWAL can improve data writing performance by 10%–30%.Furthermore,the results of YCSB(Yahoo!Cloud Serving Benchmark)show that the latency decreased by 50%compared with SpanDB.
基金Supported by the National Key Research and Development Plan(2016YFA0401600)the National Natural Science Foundation of China(11675155,11790321)。
文摘The Back-n white neutron source(known as Back-n)is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source(CSNS).With its excellent beam properties,e.g.,a neutron flux of approximately 1.8×107 n/cm2/s at 55 m from the spallation target,energy range spanning from 0.5 eV to 200 MeV,and time-of-flight resolution of a few per thousand,along with the equipped physical spectrometers,Back-n is considered to be among the best facilities in the world for carrying out nuclear data measurements.Since its completion and commencement of operation in May 2018,five types of cross-section measurements concerning neutron capture cross-sections,fission cross-sections,total cross-sections,light charged particle emissions,in-beam gamma spectra,and more than forty nuclides have been measured.This article presents an overview of the experimental setup and result analysis on the neutron-induced cross-section measurements and gamma spectroscopy at Back-n in the initial years.
基金Supported by the National Natural Science Foundation of China(12375296)the Educational Commission of Hunan Province,China(21A0281)+2 种基金the Youth Innovation Promotion Association CAS(2023014)the Key Laboratory of Nuclear Data Foundation(JCKY2022201C153)the Natural Science Foundation of Hunan Province,China(2024RC3205,2024JJ2044)。
文摘The neutron total cross-section of ^(nat)Cr plays a crucial role in new nuclear engineering design and fundamental science.A new measurement of the neutron-induced total cross-sections of ^(nat)Cr was performed using the transmission method on the back-streaming white neutron beamline(Back-n)at the China Spallation Neutron Source(CSNS).The neutron energy was determined using the time-of-flight technique.The neutron total cross-sections of ^(nat)Cr were obtained across a broad energy range(0.3 eV−20 MeV)in one experiment for the first time.The resulting effective total cross-sections were compared with the existing experimental data in different energy ranges,which revealed good agreement with the evaluated libraries.Theoretical calculation of the total cross-section in the energy range of 1.5 to 20 MeV was then conducted using TALYS-1.96 and compared with the present results.The measurement provides a high-quality total cross-section of ^(nat)Cr,including detailed uncertainty data across a wide energy range,offering a valuable reference for nuclear data re-evaluation and nuclear engineering design.
基金Supported by the National Natural Science Foundation of China(12075008)the Key Laboratory of Nuclear Data foundation(6142A08200103)+1 种基金the Basic and Applied Basic Research Foundation of Guangdong Province,China(2021B1515120027)the State Key Laboratory of Nuclear Physics and Technology,Peking University(NPT2021KFJ57)。
文摘Accurate cross sections of neutron induced fission reactions are required in the design of advanced nuclear systems and the development of fission theory.Time projection chambers(TPCs),with their track reconstruction and particle identification capabilities,are considered the best detectors for high-precision fission cross section measurements.The TPC developed by the back-streaming white neutron source(Back-n)team of the China Spallation Neutron Source(CSNS)was used as the fission fragment detector in measurements.In this study,the cross sections of the ^(232)Th(n,f)reaction at five neutron energies in the 4.50−5.40 MeV region were measured.The fission fragments and α particles were well identified using our TPC,which led to a higher detection efficiency of the fission fragments and smaller uncertainty of the measured cross sections.Ours is the first measurement of the ^(232)Th(n,f)reaction using a TPC for the detection of fission fragments.With uncertainties less than 5%,our cross sections are consistent with the data in different evaluation libraries,including JENDL-4.0,ROSFOND-2010,CENDL-3.2,ENDF/B-VⅢ.0,and BROND-3.1,whose uncertainties can be reduced after future improvement of the measurement.
基金Supported by the National Natural Science Foundation of China(11775006)the National Key R&D Program of China(2016YFA0401604)。
文摘The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neutron Source(CSNS)Back-n white neutron source.By employing theΔE-E telescopes of the Light-charged Particle Detector Array(LPDA)system at 15.1°to 55.0°in the laboratory system,ratios of the angle-differential cross sections of the ^(12)C(n,xd)reactions to those of the n-p scattering were measured,and then,the angle-differential cross sections of the ^(12)C(n,xd)reactions were obtained using the angle-differential cross sections of the n-p elastic scattering from the JENDL-4.0/HE-2015 library as the standard.The obtained results are compared with data from previous measurements,all of which are based on mono-energic neutrons,the evaluated data from the JENDL-4.0/HE-2015 library and the ENDF-B/VIII.0 library,and those from theoretical calculations based on INCA code and Talys-1.9 code.Being the first white-neutron-source-based systematic measurement of the angle-differential cross sections of neutron-induced deuteron production reactions on carbon in several tens of MeV,the present work can provide a reference to the data library considering the lack of experimental data.
基金supported by the Key Clinical Projects of Peking University Third Hospital(No.Y76437-01)National Key Research and Development Program of China(No.2017YFB1002505)+2 种基金National Natural Science Foundation of China under Grant(No.61431007)Key Research and Development Program of Guangdong Province(No.2018B030339001)Doctoral Brain+X Seed Grand Program of Tsinghua University.
文摘This study applied a steady-state visual evoked potential(SSVEP)based brain–computer interface(BCI)to a patient in lock-in state with amyotrophic lateral sclerosis(ALS)and validated its feasibility for communication.The developed calibration-free and asynchronous spelling system provided a natural and efficient communication experience for the patient,achieving a maximum free-spelling accuracy above 90%and an information transfer rate of over 22.203 bits/min.A set of standard frequency scanning and task spelling data were also acquired to evaluate the patient’s SSVEP response and to facilitate further personalized BCI design.The results demonstrated that the proposed SSVEP-based BCI system was practical and efficient enough to provide daily life communication for ALS patients.
基金financially supported by the Key Laboratory of Nuclear Data foundation(6142A08200103)the Guangdong Basic and Applied Basic Research Foundation(2021B1515120027)。
文摘Accurate fission cross section data are essential for nuclear science and engineering.Traditional fission cross section measurements using the fission ionization chamber struggle to satisfy the accuracy requirements.The Time Projection Chamber(TPC)is a potential detector for high accuracy fission cross section measurement based on its track reconstruction and particle identification capacities.Using the Multi-purpose Time Projection Chamber(MTPC)at the China Spallation Neutron Source(CSNS),we have previously measured the cross sections of the ^(232)Th(n,f)reaction based on the mono-energetic neutron source at Peking University(PKU),showing the potential of high accuracy fission cross section measurement.In this study,cross sections of the ^(235)U(n,f)reaction were measured at 43 energies(10 energy bins per magnitude in equal logarithm intervals)and 215 energies(50 energy bins per magnitude in equal logarithm intervals)in the neutron energy range from 0.5 eV to 10 keV using the MTPC based on the CSNS Back-n white neutron source.The results are consistent with the data in the evaluation libraries,showing the reliability of the fission cross section measurement method using the MTPC.The measurement of the fission cross sections using the MTPC is extended from mono-energetic to white neutron sources.This study presents the first cross section results measured by the MTPC based on the CSNS Back-n white neutron source.With a longer beam time in future measurements,the uncertainties of the fission cross sections are expected to be greatly reduced.
基金supported by the National Natural Science Foundation of China(12475308)National Key Research Program of China(2023YFA1606603)the Continuous-Support Basic Scientific Research Project(BJ010261223282)。
文摘The neutron total cross section( σ_(t))of^(169)Tm is of considerable importance in the design of nuclear reactors and applications of nuclear technology.However,the σ_(t) of^(169)Tm is unavailable in the 5 keV to 2.3 MeV energy range in the Experimental Nuclear Reaction Data library and exhibits significant discrepancies among different Evaluated Nuclear Data libraries in the keV region.To clarify the discrepancies in the σ_(t) of^(169)Tm in the keV energy region,we developed a new measurement strategy using the transmission method and the time-of-flight technique and employed it at the back-streaming white neutron beamline of the China Spallation Neutron Source.The experimental background was quantitatively determined using the saturated resonance absorption technique with a 7Li-glass scintillator.The σ_(t) of^(169)Tm in the 1110 keV energy range was obtained,and the value showed good agreement with the evaluated data in the JENDL-5 library.The calculations of the optical model agree well with the results and the fine-tuned optical model parameters in TALYS validated against the 2.32.5 MeV data reported by Foster and Glasgow,with deviations below 5%.The results fill the experimental gap in the 5110 keV range and thus provide valuable input for research on nuclear reactions and evaluations of nuclear data.
