Automatic Sleep Staging Algorithm Based on Random Forest and Hidden Markov Model

In the field of medical informatics,sleep staging is a challenging and timeconsuming task undertaken by sleep experts.According to the new standard of the American Academy of Sleep Medicine(AASM),the stages of sleep are divided into wakefulness(W),rapid eye movement(REM)and non-rapid eye movement(NREM)which includes three sleep stages(N1,N2 and N3)that describe the depth of sleep.This study aims to establish an automatic sleep staging algorithm based on the improved weighted random forest(WRF)and Hidden Markov Model(HMM)using only the features extracted from double-channel EEG signals.The WRF classification model focuses on reducing the bias of the imbalance data,while the HMM model focuses on improving the detection rate of sleep staging through the relationship between adjacent sleep stages.In particular,the improved weighted RF classification model can increase the recognition rate of the N1 stage.In addition,the method of removing features with low variance is used to select meaningful and contributing feature parameters for model training.This is an innovative content of this paper.The sleep EEG data are first segmented into 30 s epochs,and the feature parameters of the epoch data are extracted from the double-channel by applying continuous wavelet packet transform(WPT).Each epoch is then segmented into 29 subepochs of 2 s long with 1 s overlap,and the frequency domain features and statistical features of each subepoch are extracted.The performance of the proposed method is tested by evaluating the accuracy(AC),Kappa coefficient,Recall(R),Precision(P)and F1-score(F1).In the Sleep-EDF database,the overall AC and Kappa coefficient obtained by WRF are 93.20%and 0.890,respectively using the subject-non-independent test.In the 10 sc*and 10 st*Sleep-EDF Expanded database,the overall AC and Kappa coefficient obtained by proposed method are 91.97%and 0.874,respectively using the subject-independent test.The best AC and Kappa coefficient of single subject can reach 96.3%and 0.912,respectively.Experimental results show that the performance of the proposed method is competitive with the most current methods and results,and the recognition rate of N1 stage is significantly improved.

Achieving High Strength-plasticity of Nanoscale Lamellar Grain Extracted from Gradient Lamellar Nickel

Traditional metallic materials usually face a dilemma between high strength and poor strain hardening capacity.However,heterogeneous structured metallic materials have been found to obviously overcome the trade-of.Herein,gradient lamellar structure was fabricated through ultrasound-aided deep rolling technique in pure Ni with high stacking fault energy after heat treatment.The gradient lamellar Ni was successively divided into the four regions.In-situ micropillar compression tests were conducted in diferent regions to reveal the corresponding microscopic mechanical properties.Microscopic characterization techniques were performed to explore underlying deformation mechanisms and the efects of microstructural parameters on deformation behaviors.This work demonstrates that the micropillar with near nanoscale lamellar thickness possesses excellent strength and plasticity.On one hand,the reason for high strength of near nanoscale micropillar is that the strength of micropillar increases with the decrease of lamellar thickness according to the Hall-Petch efect.On the other hand,numerous lamellar grain boundaries perpendicular to the loading direction is found to hinder the motion of slip bands,resulting in great strain hardening capacity in the near nanoscale lamellar micropillar.

短视频时代下养老机构品牌建设的路径探索——以A机构为例

随着中国人口老龄化趋势的加剧,养老服务行业面临着竞争加剧的市场挑战,也迎来了巨大的发展机遇,如何在激烈的市场竞争中脱颖而出成为了一项关键课题。短视频时代的到来极大地改变了人们获取信息的方式与媒介,也为企业品牌建设提供了全新路径。短视频平台能否赋能养老机构品牌建设,进而推动其长远发展?本研究以A养老机构为案例,运用扎根理论方法深入探讨了短视频时代下养老机构利用新媒体平台进行品牌建设的新路径,运用逐级编码与范畴提取展示了短视频平台如何有效提升机构知名度、建立顾客信任、吸引优秀人才、优化服务体验,不仅为养老机构提供了利用短视频平台进行品牌建设的实践指导,也为相关领域的学术研究提供了新的视角和方法论贡献。

Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post in situ mining: a column study and numerical simulation analysis

Ion-absorbed rare earth mines,leached in situ,retain a large amount of ammonium nitrogen(NH4–N)that continuously releases into the surrounding environments.However,quantitative descriptions and predictions of the transport of NH4–N across mining area with hill slopes are not fully established.Here,laboratory column experiments were designed with an inclined slope(a sand box)to examine the spatial temporal transport of NH4–N in soils collected from the ionic rare earth elements(REE)mining area.An HYDRUS-2D model simulation of the experimental data over time showed that soils had a strong adsorption capacity toward NH4–N.Chemical non-equilibrium model(CNEM)could well simulate the transport of NH4–N through the soil-packed columns.The simulation of the transport-adsorption processes at three flow rates of leaching agents revealed that low flow rate enabled a longer residence time and an increased NH4-N adsorption,but reduced the extraction efficiency for REE.During the subsequent rainwater washing process,the presence of slope resulted in the leaching of NH4–N on the surface of the slope,while the leaching of NH4–N deep inside the column was inhibited.Furthermore,the high-intensity rainfall significantly increased the leaching,highlighting the importance of considering the impact of extreme weather conditions during the leaching process.Overall,our study advances the understanding of the transport of NH4–N in mining area with hills,the impact of flow rates of leaching agents and precipitation intensities,and presents as a feasible modeling method to evaluate the environmental risks of NH4–N pollution during and post REE in situ mining activities.

Water:The lifeblood of the Earth-human system revealed in elemental correlations

1.Elements and human history The rich chemistry of Earth's elements played an inherent and multifaceted role in shaping the course of human history.Generally,the more inert an element is,the simpler it becomes to extract it from minerals,facilitating its use in the crafting of tools,devices,and weapons.

An overview of bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils

The global problem of petroleum contamination in soils seriously threatens environmental safety and human health.Current studies have successfully demonstrated the feasibility of bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils due to their easy implementation,environmental benignity,and enhanced removal efficiency compared to bioremediation.This paper reviewed recent progress and development associated with bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils.The working principles,removal efficiencies,affecting factors,and constraints of the two technologies were thoroughly summarized and discussed.The potentials,challenges,and future perspectives were also deliberated to shed light on how to overcome the barriers and realize widespread implementation on large scales of these two technologies.

Enrichment and transfer of polycyclic aromatic hydrocarbons (PAHs) through dust aerosol generation from soil to the air

Polycyclic aromatic hydrocarbons(PAHs)are major organic pollutants in soil.It is known that they are released to the atmosphere by wind via dust aerosol generation.However,it remains unclear how these pollutants are transferred through the air/soil interface.In this study,dust aerosols were generated in the laboratory using soils(sandy loam and loam)with various physicochemical properties.The PAH concentrations of these soils and their generated dust aerosol were measured,showing that the enrichment factors(EFs)of PAHs were affected by soil texture,PAH contamination level,molecular weight of PAH species and aerosol sizes.The PAHs with higher EFs(6.24–123.35 in dust PM_(2.5);7.02–47.65 in dust PM_(10))usually had high molecular weights with more than four aromatic rings.In addition,the positive correlation between EFs of PAHs and the total OCaerosol content of dust aerosol in different particle sizes was also statistically significant(r=0.440,P<0.05).This work provides insights into the relationship between atmospheric PAHs and the contaminated soils and the transfer process of PAHs through the soil-air interface.

Oligomers from the Synthetic Polymers:Another Potential Iceberg of New Pollutants

Pollution generated by synthetic polymers,particularly plastics,has become a significant global environmental problem.However,when compared to polymer-derived products like microplastics,oligomers have not received the attention they deserve.Oligomers are by-products of polymer production and intermediates of degradation.Despite the industrial advancements leading to an exponential increase in the production of new polymers,a majority of oligomers have remained inadequately researched.While the exposure and toxic effects of polylactic acid oligomers have been documented,the structures and fundamental properties of oligomers derived from most polymers are still poorly understood.This knowledge gap presents challenges in establishing effective analytical methods.Considering the potential of oligomers to act as new pollutants,it is imperative to investigate their environmental behavior,as well as their absorption,distribution,metabolism,excretion,and toxicity(ADMET)properties.This perspective highlights the research gap concerning oligomers.

距今9500~1800年前的山东地区人群母系遗传结构

山东是中国北部沿海地区的一个多元文化中心,此前有考古和古DNA研究表明山东人群的祖先和东亚南方以及北方人群有关,但是相关研究所涉及样本的时间和地理范围有限,不能动态了解该地区的人群遗传历史.本研究首次针对山东古代人群展开大规模的线粒体基因组研究,捕获测序了来自山东12个考古遗址的、距今9500至1800年的86个人类线粒体全基因组,在大时空框架下揭示山东人群在不同时期的遗传特点与动态变化.在早于距今4600年的个体中,我们发现了在现今东亚南、北方人群中常见的单倍体群D4、D5、B4c1和B5b2.而在晚于距今4600年的个体中,开始出现单倍群C(C7a1和C7b)、M9(M9a1)和F(F1a1、F2a和F4a1),这表明山东古代人群的母系遗传结构从龙山文化早期就开始发生变化.此外,研究发现在山东地区内部,沿海和内陆地区之间的人群可能在距今约3100年以来发生了基因交换.最后,我们还研究了山东古代人群中多个B5b2谱系个体,发现其中距今年代最久的扁扁洞个体可能与该谱系的某些东亚人群和北亚人群的祖先有关.通过重建山东古代人群的母系遗传结构,本研究更清晰地探究了过去约9000年来东亚北方沿海地区人群的动态历史.

REGγ drives Lgr5^(+) stem cells to potentiate radiation induced intestinal regeneration

Leucine-rich repeat containing G protein-coupled receptor 5(Lgr5), a marker of intestinal stem cells(ISCs), is considered to play key roles in tissue homoeostasis and regeneration after acute radiation injury. However, the activation of Lgr5 by integrated signaling pathways upon radiation remains poorly understood. Here, we show that irradiation of mice with whole-body depletion or conditional ablation of REGγ in Lgr5^(+) stem cell impairs proliferation of intestinal crypts, delaying regeneration of intestine epithelial cells. Mechanistically, REGγ enhances transcriptional activation of Lgr5 via the potentiation of both Wnt and Hippo signal pathways. TEAD4 alone or cooperates with TCF4, a transcription factor mediating Wnt signaling, to enhance the expression of Lgr5. Silencing TEAD4 drastically attenuated β-catenin/TCF4 dependent expression of Lgr5. Together, our study reveals how REGγ controls Lgr5 expression and expansion of Lgr5+stem cells in the regeneration of intestinal epithelial cells.Thus, REGγ proteasome appears to be a potential therapeutic target for radiation-induced gastrointestinal disorders.