WDR49阳性星形胶质细胞标志额颞叶变性及阿尔茨海默病中神经退行性病变的严重程度

最近在具有GRN致病变异的额颞叶变性(FTLD)中鉴定出一类表达WD重复结构域49(WDR49)的星形胶质细胞亚群。本研究是首次调查这些细胞在其他FTLD亚型和阿尔茨海默病(AD)中的表达及其与病理关系的研究。研究对一组死后脑组织样本进行了免疫组织化学和免疫荧光分析,样本包括TDP-43蛋白病患者(12例GRN、11例C9orf72、9例散发性TDP-43)、tau蛋白病患者(13例MAPT、8例散发性tau)、10例AD患者和4例对照组,分析部位为额叶、颞叶和枕叶皮质切片中的WDR49和病理性包涵体。研究计算了WDR49阳性细胞数(每平方毫米调整值),并研究了其与TDP-43/tau病理数字化定量面积百分比和神经退行性病变半定量评分的相关性。对WDR49和病理性包涵体进行了定量共定位分析。在FTLD各亚型和AD的大脑实质和(周)血管间隙中均存在WDR49阳性星形胶质细胞,它们具有不同的形态模式,尤其在灰质中富集。在对照组中,发现散在的WDR49阳性细胞包裹着血管。在GRN病例的额叶皮质(FC)、GRN、AD和散发性原发性tau蛋白病的颞叶皮质中,WDR49阳性星形胶质细胞数量最多。在枕叶皮质中,各组中仅发现少量细胞。WDR49阳性星形胶质细胞数量与神经退行性病变和TDP-43病理的严重程度呈正相关,但与tau蛋白病无关。此外,在前额叶和颞叶皮质中,WDR49与TDP-43(14%~21%)和tau(31%~45%)部分共定位。总之,WDR49是FTLD和AD中不同形态星形胶质细胞亚群的标志物,反映了神经退行性病变的严重程度。这些星形胶质细胞可能对病理损伤产生反应而活化,并从血管壁迁移到实质中。

WDR82在神经胶质瘤发生发展中的作用及其机制

目的探讨WD重复结构域82(WDR82)蛋白在神经胶质瘤发生发展中的作用及其机制。方法利用GEPIA和UALCAN数据库分析WDR82在神经胶质瘤组织中的表达情况;采用Kaplan-Meier生存分析WDR82表达与神经胶质瘤患者预后的关系。采用组织芯片进行免疫组织化学染色检测WDR82在神经胶质瘤组织及其癌旁组织中的表达情况。取人胶质瘤A172和U251细胞,设置对照组(转染3μg pcDNA3)、p WDR82组(转染3μg pWDR82)、shR-Con组(转染3μg pSilencer2.1-U6)、shR-WDR82组(转染3μg shR-WDR82)。转染48 h后,采用q RT-PCR验证各组转染效率;CCK-8法检测转染48 h的细胞活性,克隆形成实验检测转染后14 d的细胞增殖能力,流式细胞术检测转染48 h的细胞凋亡情况;Western blotting检测转染48 h细胞中增殖相关蛋白及Akt/mTOR信号通路相关蛋白的表达。采用体内荷瘤实验检测WDR82对NOD-SCID小鼠肿瘤生长的影响。结果GEPIA和UALCAN数据库分析及免疫组织化学染色结果显示,WDR82在神经胶质瘤组织中的表达水平明显高于癌旁正常组织(P<0.05),其表达在不同性别及年龄段患者间差异无统计学意义(P>0.05)。Kaplan-Meier生存分析结果显示,高表达WDR82的神经胶质瘤患者的预后不良(log-rank P=0.029)。过表达WDR82可明显促进A172和U251细胞的增殖,抑制细胞凋亡,明显增高A172和U251细胞中MKI67、BCL2、CCND1、p-Akt和p-mTOR的表达(P<0.05)。反之,敲降WDR82则抑制A172和U251细胞的增殖,促进细胞凋亡,降低MKI67、BCL2、CCND1、p-Akt和p-mTOR的表达(P<0.05)。敲降U251细胞中的WDR82,可明显抑制荷瘤NOD-SCID小鼠肿瘤的生长(P<0.05)。结论高表达WDR82可能通过调控Akt/mTOR信号通路促进神经胶质瘤细胞的增殖及体内肿瘤的生长。

WDR63促进人根尖牙乳头干细胞成神经分化功能

目的:研究WD重复结构域63(WDR63)对人根尖牙乳头干细胞(SCAPs)体外成神经分化能力的作用。方法:通过实时荧光定量PCR检测未转染慢病毒SCAPs中WDR63基因在成神经分化诱导3、6、9 d的表达变化,利用慢病毒转染分别获得WDR63稳定过表达和敲低的SCAPs,通过类神经球形成实验对各组SCAPs进行神经分化诱导,对类神经球的直径进行定量分析,免疫荧光染色实验检测SCAPs中巢蛋白(Nestin)和βⅢ-微管蛋白(βⅢ-tubulin)的表达,实时荧光定量PCR实验检测神经分化相关指标βⅢ-tubulin、神经源性分化蛋白(NeuroD)、神经细胞黏附分子(NCAM)和Nestin基因的表达。结果:未转染慢病毒SCAPs中WDR63的表达量在成神经分化后的3、6、9 d逐渐增加(P<0.05);过表达WDR63后,WDR63基因(P<0.001)和蛋白表达增加,神经球直径增加(P<0.01),Nestin和βⅢ-tubulin神经球样细胞荧光强度增加(P<0.01),βⅢ-tubulin、NeuroD、NCAM和Nestin基因表达升高(P<0.05);敲低WDR63后,WDR63基因(P<0.01)和蛋白的表达降低,神经球直径降低(P<0.05),Nestin和βⅢ-tubulin神经球样细胞荧光强度减少(P<0.05),βⅢ-tubulin、NeuroD、NCAM和Nestin基因表达降低(P<0.05)。结论:WDR63可促进SCAPs的成神经分化功能。

Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China

Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.

WDR4基因在肺腺癌中的表达、预后及免疫特征分析

目的:探讨WD重复结构域4(WDR4)基因在肺腺癌(LUAD)中的表达、预后及免疫浸润的临床意义。方法:通过肿瘤基因组图谱(TCGA)收集535例LUAD患者临床病理资料和WDR4 mRNA表达数据,临床蛋白质组肿瘤分析协作组(CPTAC)公共数据库收集111例WDR4蛋白表达数据,R语言分析LUAD组织中WDR4表达与患者临床病理特征及生存期的关系;受试者工作特征(ROC)曲线分析WDR4表达对LUAD的诊断价值;Estimate及ssGSEA算法分析WDR4表达与LUAD肿瘤微环境及免疫细胞浸润水平的相关性。结果:WDR4 mRNA在LUAD组织中的表达明显高于正常组织(均P<0.001);WDR4蛋白水平也显著上调(P<0.05)。临床特征分析显示WDR4表达与LUAD患者淋巴结转移相关(P<0.05)。Log-rank检验结果显示,WDR4高表达组总生存期明显低于低表达组(P=0.004);多因素Cox回归分析显示:T分期、淋巴结转移和WDR4 mRNA表达是LUAD患者预后的独立影响因素,WDR4 mRNA高表达患者死亡风险是低表达的1.478倍(95%CI:1.041~2.097)。ROC曲线分析显示WDR4 mRNA表达对LUAD诊断具有较高的预测效能(AUC=0.912,95%CI:0.885~0.939)。WDR4高表达与肿瘤微环境免疫浸润水平总体呈负相关(均P<0.05)。结论:WDR4在LUAD组织中表达较正常肺组织显著上调,高表达患者预后不良,抑制肿瘤微环境免疫细胞浸润,WDR4可能是评估LUAD患者诊断、预后的潜在生物学标志物和治疗靶点。

Extraction of Acoustic Normal Mode Depth Functions Using Range-Difference Method with Vertical Linear Array Data

Data-derived normal mode extraction is an effective method for extracting normal mode depth functions in the absence of marine environmental data.However,when the corresponding singular vectors become nonunique when two or more singular values obtained from the cross-spectral density matrix diagonalization are nearly equal,this results in unsatisfactory extraction outcomes for the normal mode depth functions.To address this issue,we introduced in this paper a range-difference singular value decomposition method for the extraction of normal mode depth functions.We performed the mode extraction by conducting singular value decomposition on the individual frequency components of the signal's cross-spectral density matrix.This was achieved by using pressure and its range-difference matrices constructed from vertical line array data.The proposed method was validated using simulated data.In addition,modes were successfully extracted from ambient noise.

Influence of network structure on spreading dynamics via tie range

There are various phenomena of malicious information spreading in the real society, which cause many negative impacts on the society. In order to better control the spreading, it is crucial to reveal the influence of network structure on network spreading. Motifs, as fundamental structures within a network, play a significant role in spreading. Therefore, it is of interest to investigate the influence of the structural characteristics of basic network motifs on spreading dynamics.Considering the edges of the basic network motifs in an undirected network correspond to different tie ranges, two edge removal strategies are proposed, short ties priority removal strategy and long ties priority removal strategy. The tie range represents the second shortest path length between two connected nodes. The study focuses on analyzing how the proposed strategies impact network spreading and network structure, as well as examining the influence of network structure on network spreading. Our findings indicate that the long ties priority removal strategy is most effective in controlling network spreading, especially in terms of spread range and spread velocity. In terms of network structure, the clustering coefficient and the diameter of network also have an effect on the network spreading, and the triangular structure as an important motif structure effectively inhibits the spreading.

On the Adaptability Range, Self-Selection, and Economic Nature of Biological Evolution

This article employs a combined approach of biology and economics to reveal that biological evolution has an economic nature, evolving towards improved energy efficiency. The orthodox Darwinian theory of evolution describes evolution as the random variation of organisms and their survival through natural selection. In fact, the natural environment itself is a constantly changing context, and the strategy to adapt to this change is to enhance behavioral capabilities, thereby expanding the range and dimensions of behavior. Therefore, the improvement of behavioral capabilities is an important aspect of evolution. The enhancement of behavioral capabilities expands the range of adaptation to the natural environment and increases the space for behavioral choices. Within this space of behavioral choices, some options are more effective and superior to others;thus, the ability to select is necessary to make the improved behavioral capabilities more beneficial to the organism itself. The birth and development of the brain serve the purpose of selection. By using the brain to make selections, at least the “better” behavior will be chosen between two alternatives. Once the better behavior yields better results, and the organism can associate these results with the corresponding behavior, it will persist in this behavior. The persistent repetition of a behavior over generations will form a habit. Habits passed down through generations constitute a new environment, causing the organism’s genes to activate or deactivate certain functions, ultimately leading to genetic changes that are beneficial to that habit. Since the brain’s selection represents the organism’s self-selection, it differs from random variation;it is also a rational selection, choosing behaviors that either obtain more energy or reduce energy consumption. Thus, this evolution possesses an economic nature.

Image Steganography by Pixel-Value Differencing Using General Quantization Ranges

A new steganographic method by pixel-value differencing(PVD)using general quantization ranges of pixel pairs’difference values is proposed.The objective of this method is to provide a data embedding technique with a range table with range widths not limited to powers of 2,extending PVD-based methods to enhance their flexibility and data-embedding rates without changing their capabilities to resist security attacks.Specifically,the conventional PVD technique partitions a grayscale image into 1×2 non-overlapping blocks.The entire range[0,255]of all possible absolute values of the pixel pairs’grayscale differences in the blocks is divided into multiple quantization ranges.The width of each quantization range is a power of two to facilitate the direct embedding of the bit information with high embedding rates.Without using power-of-two range widths,the embedding rates can drop using conventional embedding techniques.In contrast,the proposed method uses general quantization range widths,and a multiple-based number conversion mechanism is employed skillfully to implement the use of nonpower-of-two range widths,with each pixel pair being employed to embed a digit in the multiple-based number.All the message bits are converted into a big multiple-based number whose digits can be embedded into the pixel pairs with a higher embedding rate.Good experimental results showed the feasibility of the proposed method and its resistance to security attacks.In addition,implementation examples are provided,where the proposed method adopts non-power-of-two range widths and employsmultiple-based number conversion to expand the data-hiding and steganalysis-resisting capabilities of other PVD methods.

Extending the solid solution range of sodium ferric pyrophosphate:Off‐stoichiometric Na_(3)Fe(2.5)(P_(2)O_(7))_(2)as a novel cathode for sodium‐ion batteries

Iron‐based pyrophosphates are attractive cathodes for sodium‐ion batteries due to their large framework,cost‐effectiveness,and high energy density.However,the understanding of the crystal structure is scarce and only a limited candidates have been reported so far.In this work,we found for the first time that a continuous solid solution,Na_(4−α)Fe_(2+α)_(2)(P_(2)O_(7))_(2)(0≤α≤1,could be obtained by mutual substitution of cations at center‐symmetric Na3 and Na4 sites while keeping the crystal building blocks of anionic P_(2)O_(7) unchanged.In particular,a novel off‐stoichiometric Na_(3)Fe(2.5)(P_(2)O_(7))_(2)is thus proposed,and its structure,energy storage mechanism,and electrochemical performance are extensively investigated to unveil the structure–function relationship.The as‐prepared off‐stoichiometric electrode delivers appealing performance with a reversible discharge capacity of 83 mAh g^(−1),a working voltage of 2.9 V(vs.Na^(+)/Na),the retention of 89.2%of the initial capacity after 500 cycles,and enhanced rate capability of 51 mAh g^(−1)at a current density of 1600 mA g^(−1).This research shows that sodium ferric pyrophosphate could form extended solid solution composition and promising phase is concealed in the range of Na_(4−α)Fe_(2+α)_(2)(P_(2)O_(7))_(2),offering more chances for exploration of new cathode materials for the construction of high‐performance SIBs.

LFM Radar Source Passive Localization Algorithm Based on Range Migration

Traditional single-satellite passive localization algorithms are influenced by frequency and angle measurement accuracies,resulting in error estimation of emitter position on the order of kilometers.Subsequently,a single-satellite localization algorithm based on passive synthetic aper-ture(PSA)was introduced,enabling high-precision positioning.However,its estimation of azimuth and range distance is considerably affected by the residual frequency offset(RFO)of uncoopera-tive system transceivers.Furthermore,it requires data containing a satellite flying over the radia-tion source for RFO search.After estimating the RFO,an accurate estimation of azimuth and range distance can be carried out,which is difficult to achieve in practical situations.An LFM radar source passive localization algorithm based on range migration is proposed to address the dif-ficulty in estimating frequency offset.The algorithm first provides a rough estimate of the pulse repetition time(PRT).It processes intercepted signals through range compression,range interpola-tion,and polynomial fitting to obtain range migration observations.Subsequently,it uses the changing information of range migration and an accurate PRT to formulate a system of nonlinear equations,obtaining the emitter position and a more accurate PRT through a two-step localization algorithm.Frequency offset only induces a fixed offset in range migration,which does not affect the changing information.This algorithm can also achieve high-precision localization in squint scenar-ios.Finally,the effectiveness of this algorithm is verified through simulations.

伯氏疏螺旋体在HMC3细胞感染模型中WDR36和WRN基因的表达分析

目的为探索神经莱姆病的分子机制,通过转录组学与伯氏疏螺旋体感染发现相关的2个基因WDR36和WRN,以证明其具有靶点治疗的潜力。方法通过建立非人灵长类动物模型,利用高通量测序技术获取转录组学数据。通过GO富集分析,识别出2个具有研究价值的WDR36和WRN差异表达基因。为进一步验证这2个基因在Bb感染神经莱姆病中的作用,采用人脑胶质细胞HMC3细胞株作为模型。实验组细胞接受了不同MOI(1和10)的Bb接种,并在感染后6 h、12 h和24 h收集细胞悬液。使用trizol法提取RNA,并通过qPCR法测定WDR36和WRN基因的mRNA相对表达水平。结果在Bb感染的HMC3细胞中,发现Bb MOI=1为适宜感染浓度。结果表明WDR36的表达量在24 h与12 h对比有显著的上调(P<0.01),且6 h的PBS组与试验组基因表达含量对比上升但不明显(P>0.05),12 h、24 h上升明显,差异有统计学意义(P<0.01),WRN的表达量在24 h与12 h对比有显著上调,且6 h、12 h、24 h的实验组分别比其PBS组基因表达含量呈上升趋势,差异有统计学意义(P<0.01)。结论WDR36和WRN的上调可能与LNB的神经病理过程相关,这些发现为进一步研究LNB的分子机制提供了新的视角,并可能为开发针对Bb感染的新型治疗方案提供潜在的分子靶点。

The interaction between temperature and precipitation on the potential distribution range of Betula ermanii in the alpine treeline ecotone on the Changbai Mountain

Alpine treeline ecotones are highly sensitive to climate warming.The low temperature-determined alpine treeline is expected to shift upwards in response to global warming.However,little is known about how temperature interacts with other important factors to influence the distribution range of tree species within and beyond the alpine treeline ecotone.Hence,we used a GF-2 satellite image,along with bioclimatic and topographic variables,to develop an ensemble suitable habitat model based on the species distribution modeling algorithms in Biomod2.We investigated the distribution of suitable habitats for B.ermanii under three climate change scenarios(i.e.,low(SSP126),moderate(SSP370)and extreme(SSP585)future emission trajectories)between two consecutive time periods(i.e.,current-2055,and 2055-2085).By 2055,the potential distribution range of B.ermanii will expand under all three climate scenarios.The medium and high suitable areas will decline under SSP370 and SSP585scenarios from 2055 to 2085.Moreover,under the three climate scenarios,the uppermost altitudes of low suitable habitat will rise to 2,329 m a.s.l.,while the altitudes of medium and high suitable habitats will fall to 2,201 and2,051 m a.s.l.by 2085,respectively.Warming promotes the expansion of B.ermanii distribution range in Changbai Mountain,and this expansion will be modified by precipitation as climate warming continues.This interaction between temperature and precipitation plays a significant role in shaping the potential distribution range of B.ermanii in the alpine treeline ecotone.This study reveals the link between environmental factors,habitat distribution,and species distribution in the alpine treeline ecotone,providing valuable insights into the impacts of climate change on high-elevation vegetation,and contributing to mountain biodiversity conservation and sustainable development.

Design and Verification for Dual⁃mode CDFS and High⁃Load Compressor with a Large Flow Regulation Range

This paper presents the design and verification of the dual-mode core driven fan stage(CDFS)and high-load compressor with a large flow regulation range.In view of the characteristics of large flow regulation range of the two modes and high average stage load coefficient,this paper investigates the design technology of the dual-mode high-efficiency compressor with a large flow regulation range and high-load compressor with an average stage load coefficient of 0.504.Building upon this research,the design of the dual-mode CDFS and four-stage compressor is completed,and three-dimensional numerical simulation of the two modes is carried out.Finally,performance experiment is conducted to verify the result of three-dimensional numerical simulation.The experiment results show that the compressor performance is improved for the whole working conditions by using the new design method,which realizes the complete fusion design of the CDFS and high-pressure compressor(HPC).The matching mechanism of stage characteristics of single and double bypass modes and the variation rule of different adjustment angles on performance are studied comprehensively.Furthermore,it effectively reduces the length and weight of compressor,and breaks through the key technologies such as high-load compressor with the average load factor of 0.504.These findings provide valuable data and a methodological foundation for the development of the next generation aeroengine.

Study of the response of 10B-doped MCP to wide-energy range neutrons from eV to MeV

Neutron-sensitive microchannel plates(nMCPs)have applications in neutron detection,including energy spectrum measurements,neutron-induced cross sections,and neutron imaging.10B-doped MCPs(B-MCPs)have attracted significant attention owing to their potential for exhibiting a high neutron detection efficiency over a large neutron energy range.Good spatial and temporal resolutions are useful for neutron energy-resolved imaging.However,their practical applications still face many technical challenges.In this study,a B-MCP with 10 mol%10B was tested for its response to wide-energy neutrons from eV to MeV at the Back-n white neutron source at the China Spallation Neutron Source.The neutron detection efficiency was calibrated at 1 eV,which is approximately 300 times that of an ordinary MCP and indicates the success of 10 B doping.The factors that caused the reduction in the detection efficiency were simulated and discussed.The neutron energy spectrum obtained using B-MCP was compared with that obtained by other measurement methods,and showed very good consistency for neutron energies below tens of keV.The response is more complicated at higher neutron energy,at which point the elastic and nonelastic reactions of all nuclides of B-MCP gradually become dominant.This is beneficial for the detection of neutrons,as it compensates for the detection efficiency of B-MCP for high-energy neutrons.

Spatiotemporal Evaluation and Future Projection of Diurnal Temperature Range over the Tibetan Plateau in CMIP6 Models

The diurnal temperature range(DTR) serves as a vital indicator reflecting both natural climate variability and anthropogenic climate change. This study investigates the historical and projected multitemporal DTR variations over the Tibetan Plateau. It assesses 23 climate models from phase 6 of the Coupled Model Intercomparison Project(CMIP6) using CN05.1 observational data as validation, evaluating their ability to simulate DTR over the Tibetan Plateau. Then, the evolution of DTR over the Tibetan Plateau under different shared socioeconomic pathway(SSP) scenarios for the near,middle, and long term of future projection are analyzed using 11 selected robustly performing models. Key findings reveal:(1) Among the models examined, BCC-CSM2-MR, EC-Earth3, EC-Earth3-CC, EC-Earth3-Veg, EC-Earth3-Veg-LR,FGOALS-g3, FIO-ESM-2-0, GFDL-ESM4, MPI-ESM1-2-HR, MPI-ESM1-2-LR, and INM-CM5-0 exhibit superior integrated simulation capability for capturing the spatiotemporal variability of DTR over the Tibetan Plateau.(2) Projection indicates a slightly increasing trend in DTR on the Tibetan Plateau in the SSP1-2.6 scenario, and decreasing trends in the SSP2-4.5, SSP3-7.0, and SPP5-8.5 scenarios. In certain areas, such as the southeastern edge of the Tibetan Plateau, western hinterland of the Tibetan Plateau, southern Kunlun, and the Qaidam basins, the changes in DTR are relatively large.(3) Notably, the warming rate of maximum temperature under SSP2-4.5, SSP3-7.0, and SPP5-8.5 is slower compared to that of minimum temperature, and it emerges as the primary contributor to the projected decrease in DTR over the Tibetan Plateau in the future.

Design of a high sensitivity and wide range angular rate sensor based on exceptional surface

It is found that when the parity–time symmetry phenomenon is introduced into the resonant optical gyro system and it works near the exceptional point,the sensitivity can in theory be significantly amplified at low angular rate.However,in fact,the exceptional point is easily disturbed by external environmental variables,which means that it depends on harsh experimental environment and strong control ability,so it is difficult to move towards practical application.Here,we propose a new angular rate sensor structure based on exceptional surface,which has the advantages of high sensitivity and high robustness.The system consists of two fiber-optic ring resonators and two optical loop mirrors,and one of the resonators contains a variable ratio coupler and a variable optical attenuator.We theoretically analyze the system response,and the effects of phase and coupling ratio on the system response.Finally,compared with the conventional resonant gyro,the sensitivity of this exceptional surface angular rate sensor can be improved by about 300 times at low speed.In addition,by changing the loss coefficient in the ring resonator,we can achieve a wide range of 600 rad/s.This scheme provides a new approach for the development of ultra-high sensitivity and wide range angular rate sensors in the future.

Analysis of application range of simplified models for field to thermo-field to thermionic emission processes from the cathode

Electron emission plays a dominant role in plasma-cathode interactions and is a key factor in many plasma phenomena and industrial applications.It is necessary to illustrate the various electron emission mechanisms and the corresponding applicable description models to evaluate their impacts on discharge properties.In this study,detailed expressions of the simplified formulas valid for field emission to thermo-field emission to thermionic emission typically used in the numerical simulation are proposed,and the corresponding application ranges are determined in the framework of the Murphy-Good theory,which is commonly regarded as the general model and to be accurate in the full range of conditions of the validity of the theory.Dimensionless parameterization was used to evaluate the emission current density of the Murphy-Good formula,and a deviation factor was defined to obtain the application ranges for different work functions(2.5‒5 eV),cathode temperatures(300‒6000 K),and emitted electric fields(10^(5) to 10^(10) V·m^(-1)).The deviation factor was shown to be a nonmonotonic function of the three parameters.A comparative study of particle number densities in atmospheric gas discharge with a tungsten cathode was performed based on the one-dimensional implicit particle-in-cell(PIC)with the Monte Carlo collision(MCC)method according to the aforementioned application ranges.It was found that small differences in emission current density can lead to variations in the distributions of particle number density due to changes in the collisional environment.This study provides a theoretical basis for selecting emission models for subsequent numerical simulations.

Robust Timing Constraints for Granitic Magmatism and Hydrothermal Mineralization in the Tieshanlong W-Sn Ore Field,Eastern Nanling Range,South China

The Tieshanlong ore field is an important part of the Nanling Range,which is famous worldwide for its W-Sn mineralization.Notably,the mineralization age of the Tieshanlong ore field is not well constrained,and our field investigation reveals that granitic emplacement occurred at different stages.However,previous studies have not distinguished these multiple stages of magmatism.The Tieshanlong granite complex is closely related to the Huangsha quartz vein-type W-Sn deposit and Tongling skarn-type Cu-W-Sn deposit in this field.Through field investigations and isotopic age analyses,this work studies the relationship between multistage magmatic activity and mineralization in the Tieshanlong ore field.LA-ICP-MS zircon U-Pb isotope analyses revealed that the first-and second-staged granites formed at 154.2±0.6 Ma(MSDW=1.4)and 151.2±0.4 Ma(MSDW=1.5),with zirconε_(Hf)(t)values ranging from-13.1 to-10.5 and from-14.7 to-11.1,respectively.These data suggest that the Tieshanlong granite complex was derived from the partial melting of ancient crustal material.LA-ICP-MS U-Pb dating of wolframite and cassiterite reveals that W-Sn mineralization occurred at 160-150 Ma,which agrees well with the U-Pb dating results of the second-staged granite within analytical errors.The magmatic activity in this ore field can be divided into three stages:175-154 Ma,154-150 Ma and 150-145 Ma.The quartz vein-and skarn-type W-Sn mineralization is closely related to second-staged fine-grained twomica granite,and formed earlier than skarn-type Cu-mineralization.This study establishes a metallogenic model for the Tieshanlong ore field,and this model has important practical significance for identifying concealed W-Sn(-Cu)deposits around other granitic complexes in the Nanling Range.

Simulation Study on the Migration Range of CO_(2) in the Offshore Saline Aquifer

The geological storage of carbon dioxide(CO_(2)) is a crucial technology for mitigating climate change. Offshore deep saline aquifers have elicited increased attention due to their remarkable potential for storing CO_(2). During long-term storage, CO_(2) migration in a deep saline aquifer needs special attention to prevent it from reaching risk points and leading to security issues. In this paper, a mechanism model is established according to the geological characteristics of saline aquifers in an offshore sedimentary basin in China. The CO_(2) migration over 100 years is simulated considering geological changes such as permeability, dip angle, thickness, and salinity. The effects of injection conditions on the CO_(2) migration range are also investigated. Results reveal that the migration range of CO_(2) in the injection period exceeds 70%, even if the postinjection period's duration is five times longer than that of the injection period. As the values of the above geological parameters increase, the migration range of CO_(2) increases, and permeability has a particularly substantial influence. Moreover, the influences of injection rate and well type are considerable. At high injection rates, CO_(2) has a greater likelihood of displacing brine in a piston-like scheme. CO_(2) injected by long horizontal wells migrates farther compared with that injected by vertical wells. In general, the plane migration range is within 3 000 m, although variations in the reservoir and injection parameters of the studied offshore saline aquifers are considered. This paper can offer references for the site selection and injection well deployment of CO_(2) saline aquifer storage. According to the studied offshore aquifers, a distance of at least 3 000 m from potential leakage points, such as spill points, active faults, and old abandoned wells, must be maintained.