Evaluation of the intracellular lipid-lowering effect of polyphenols extract from highland barley in HepG2 cells

Active ingredients from highland barley have received considerable attention as natural products for developing treatments and dietary supplements against obesity.In practical application,the research of food combinations is more significant than a specific food component.This study investigated the lipid-lowering effect of highland barley polyphenols via lipase assay in vitro and HepG2 cells induced by oleic acid(OA).Five indexes,triglyceride(TG),total cholesterol(T-CHO),low density lipoprotein-cholesterol(LDL-C),aspartate aminotransferase(AST),and alanine aminotransferase(ALT),were used to evaluate the lipidlowering effect of highland barley extract.We also preliminary studied the lipid-lowering mechanism by Realtime fluorescent quantitative polymerase chain reaction(q PCR).The results indicated that highland barley extract contains many components with lipid-lowering effects,such as hyperoside and scoparone.In vitro,the lipase assay showed an 18.4%lipase inhibition rate when the additive contents of highland barley extract were 100μg/m L.The intracellular lipid-lowering effect of highland barley extract was examined using 0.25 mmol/L OA-induced HepG2 cells.The results showed that intracellular TG,LDL-C,and T-CHO content decreased by 34.4%,51.2%,and 18.4%,respectively.ALT and AST decreased by 51.6%and 20.7%compared with the untreated hyperlipidemic HepG2 cells.q PCR results showed that highland barley polyphenols could up-regulation the expression of lipid metabolism-related genes such as PPARγand Fabp4.

Fully automatic AI segmentation of oral surgery-related tissues based on cone beam computed tomography images

Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical accuracy.In this paper,we propose a fully automated tissue segmentation system for dental implant surgery.Specifically,we propose an image preprocessing method based on data distribution histograms,which can adaptively process CBCT images with different parameters.Based on this,we use the bone segmentation network to obtain the segmentation results of alveolar bone,teeth,and maxillary sinus.We use the tooth and mandibular regions as the ROI regions of tooth segmentation and mandibular nerve tube segmentation to achieve the corresponding tasks.The tooth segmentation results can obtain the order information of the dentition.The corresponding experimental results show that our method can achieve higher segmentation accuracy and efficiency compared to existing methods.Its average Dice scores on the tooth,alveolar bone,maxillary sinus,and mandibular canal segmentation tasks were 96.5%,95.4%,93.6%,and 94.8%,respectively.These results demonstrate that it can accelerate the development of digital dentistry.

Dynamic characteristics of multi-span spinning beams with elastic constraints under an axial compressive force

A theoretical model for the multi-span spinning beams with elastic constraints under an axial compressive force is proposed.The displacement and bending angle functions are represented through an improved Fourier series,which ensures the continuity of the derivative at the boundary and enhances the convergence.The exact characteristic equations of the multi-span spinning beams with elastic constraints under an axial compressive force are derived by the Lagrange equation.The efficiency and accuracy of the present method are validated in comparison with the finite element method(FEM)and other methods.The effects of the boundary spring stiffness,the number of spans,the spinning velocity,and the axial compressive force on the dynamic characteristics of the multi-span spinning beams are studied.The results show that the present method can freely simulate any boundary constraints without modifying the solution process.The elastic range of linear springs is larger than that of torsion springs,and it is not affected by the number of spans.With an increase in the axial compressive force,the attenuation rate of the natural frequency of a spinning beam with a large number of spans becomes larger,while the attenuation rate with an elastic boundary is lower than that under a classic simply supported boundary.

Mass-spring model for elastic wave propagation in multilayered van der Waals metamaterials

Multilayered van der Waals(vdW)materials have attracted increasing interest because of the manipulability of their superior optical,electrical,thermal,and mechanical properties.A mass-spring model(MSM)for elastic wave propagation in multilayered vdW metamaterials is reported in this paper.Molecular dynamics(MD)simulations are adopted to simulate the propagation of elastic waves in multilayered vdW metamaterials.The results show that the graphene/MoS_(2)metamaterials have an elastic wave bandgap in the terahertz range.The MSM for the multilayered vdW metamaterials is proposed,and the numerical simulation results show that this model can well describe the dispersion and transmission characteristics of the multilayered vdW metamaterials.The MSM can predict elastic wave transmission characteristics in multilayered vdW metamaterials stacked with different two-dimensional(2D)materials.The results presented in this paper offer theoretical help for the vibration reduction of multilayered vdW semiconductors.

Preparation of single atom catalysts for high sensitive gas sensing

Single atom catalysts(SACs)have garnered significant attention in the field of catalysis over the past decade due to their exceptional atom utilization efficiency and distinct physical and chemical properties.For the semiconductor-based electrical gas sensor,the core is the catalysis process of target gas molecules on the sensitive materials.In this context,the SACs offer great potential for highly sensitive and selective gas sensing,however,only some of the bubbles come to the surface.To facilitate practical applications,we present a comprehensive review of the preparation strategies for SACs,with a focus on overcoming the challenges of aggregation and low loading.Extensive research efforts have been devoted to investigating the gas sensing mechanism,exploring sensitive materials,optimizing device structures,and refining signal post-processing techniques.Finally,the challenges and future perspectives on the SACs based gas sensing are presented.

Vibration of black phosphorus nanotubes via orthotropic cylindrical shell model

Black phosphorus nanotubes(BPNTs)may have good properties and potential applications.Determining thevibration property of BPNTs is essential for gaining insight into the mechanical behaviour of BPNTs and designingoptimized nanodevices.In this paper,the mechanical behaviour and vibration property of BPNTs are studied viaorthotropic cylindrical shell model and molecular dynamics(MD)simulation.The vibration frequencies of twochiral BPNTs are analysed systematically.According to the results of MD calculations,it is revealed that thenatural frequencies of two BPNTs with approximately equal sizes are unequal at each order,and that the naturalfrequencies of armchair BPNTs are higher than those of zigzag BPNTs.In addition,an armchair BPNTs witha stable structure is considered as the object of research,and the vibration frequencies of BPNTs of differentsizes are analysed.When comparing the MD results,it is found that both the isotropic cylindrical shell modeland orthotropic cylindrical shell model can better predict the thermal vibration of the lower order modes of thelonger BPNTs better.However,for the vibration of shorter and thinner BPNTs,the prediction of the orthotropiccylindrical shell model is obviously superior to the isotropic shell model,thereby further proving the validity ofthe shell model that considers orthotropic for BPNTs.

Flexible Load Participation in Peaking Shaving and Valley Filling Based on Dynamic Price Incentives

Considering the widening of the peak-valley difference in the power grid and the difficulty of the existing fixed time-of-use electricity price mechanism in meeting the energy demand of heterogeneous users at various moments or motivating users,the design of a reasonable dynamic pricing mechanism to actively engage users in demand response becomes imperative for power grid companies.For this purpose,a power grid-flexible load bilevel model is constructed based on dynamic pricing,where the leader is the dispatching center and the lower-level flexible load acts as the follower.Initially,an upper-level day-ahead dispatching model for the power grid is established,considering the lowest power grid dispatching cost as the objective function and incorporating the power grid-side constraints.Then,the lower level comprehensively considers the load characteristics of industrial load,energy storage,and data centers,and then establishes a lower-level flexible load operation model with the lowest user power-consuming cost as the objective function.Finally,the proposed method is validated using the IEEE-118 system,and the findings indicate that the dynamic pricing mechanism for peaking shaving and valley filling can effectively guide users to respond actively,thereby reducing the peak-valley difference and decreasing users’purchasing costs.

基于^(18)F-FDG PET/CT代谢参数构建非小细胞肺癌PD-L1表达的列线图预测模型

背景与目的近年来,程序性细胞死亡受体1 (programmed cell death,PD-1)/程序性细胞死亡配体1 (programmed cell death ligand 1,PD-L1)免疫抑制剂为代表的免疫疗法很大程度地改变了非小细胞肺癌(nonsmall cell lung cancer,NSCLC)的治疗现状。目前PD-L1已经成为了筛选NSCLC免疫治疗获益人群的重要生物标志物,但是如何便捷且准确地检测NSCLC患者PD-L1是否表达是困扰临床医师的难题。本研究旨在基于^(18)F-脱氧葡萄糖(^(18)F-fluorodeoxy glucose,^(18)F-FDG)正电子发射计算机断层扫描(positron emission tomography/computed tomography,PET/CT)代谢参数构建NSCLC患者PD-L1表达的列线图预测模型并评估其预测价值。方法回顾性收集2016年9月至2021年7月内蒙古自治区人民医院收治的155例NSCLC患者的^(18)F-FDG PET/CT代谢参数、临床病理资料及PD-L1检测结果。将患者分为训练组(n=117)及内部验证组(n=38),按照同样的标准另收集本院2021年8月至2022年7月NSCLC患者51例作为外部验证组。然后均根据PD-L1检测结果分为PD-L1+组与PD-L1-组。对训练组患者的代谢参数及临床病理资料进行单因素及二元Logistic回归分析,基于筛选出的独立影响因素构建列线图预测模型。在训练组及内外部验证组中均通过受试者工作特征(receiver operating characteristic,ROC)曲线、校准曲线及临床决策曲线(decision curve analysis,DCA)来评估列线图模型效果。结果二元Logistic回归分析表明,肿瘤代谢体积(metabolic tumor volume,MTV)、性别及肿瘤直径是PD-L1表达的独立影响因素,然后基于上述独立影响因素构建列线图预测模型。模型在训练组中的ROC曲线显示,曲线下面积(area under the curve,AUC)为0.769 (95%CI:0.683-0.856),最佳截断值为0.538。内部验证组的AUC为0.775 (95%CI:0.614-0.936),外部验证组的AUC为0.752 (95%CI:0.612-0.893)。校准曲线经Hosmer-Lemeshow检验结果显示,训练组(χ^(2)=0.040,P=0.979)、内部验证组(χ^(2)=2.605,P=0.271)及外部验证组(χ^(2)=0.396,P=0.820)均具有良好的校准度。DCA曲线显示,模型在较大的阈值范围内(训练组:0.00-0.72,内部验证组:0.00-0.87,外部验证组:0.00-0.66)能使患者临床获益。结论基于^(18)F-FDGPET/CT代谢参数构建的列线图预测模型在预测NSCLC患者PD-L1表达中有较大的应用价值。

Machine learning-based stiffness optimization of digital composite metamaterials with desired positive or negative Poisson's ratio

Mechanical metamaterials such as auxetic materials have attracted great interest due to their unusual properties that are dictated by their architectures.However,these architected materials usually have low stiffness because of the bending or rotation deformation mechanisms in the microstructures.In this work,a convolutional neural network(CNN)based self-learning multi-objective optimization is performed to design digital composite materials.The CNN models have undergone rigorous training using randomly generated two-phase digital composite materials,along with their corresponding Poisson's ratios and stiffness values.Then the CNN models are used for designing composite material structures with the minimum Poisson's ratio at a given volume fraction constraint.Furthermore,we have designed composite materials with optimized stiffness while exhibiting a desired Poisson's ratio(negative,zero,or positive).The optimized designs have been successfully and efficiently obtained,and their validity has been confirmed through finite element analysis results.This self-learning multi-objective optimization model offers a promising approach for achieving comprehensive multi-objective optimization.

短期禁食对离体鼠心缺血心肌功能的影响

目的：评估短期禁食是否影响缺血后离体鼠心的功能。方法：灌流进食组和禁食（２４ｈ）组离体鼠心。连续记录左心室发展压（ＬＶＤＰ）、舒张末期压（ＥＤＰ）和心率（ＨＲ）。结果：与进食鼠相比，缺血后再灌期禁食鼠心显示ＥＤＰ减低，ＬＶＤＰ增高。缺血诱发的心律失常发生率减少，禁食鼠（１２６．２±１７．４６）次／ｈ，进食鼠（２２６．３３±１８．７９）次／ｈ，ｎ＝６，Ｐ＜０．００５。结论：短期禁食离体鼠心肌缺血后恢复更快、更好。

CO2 and SO2 emission characteristics of the whole process industry chain of coal processing and utilization in China

The total coal consumption in China is on the rise.The characteristics of CO2 and SO2 emissions in the whole process of coal processing and utilization in China are worthy of study.Based on the five links of the whole process of coal production and utilization,including coal production,raw coal processing,logistics and transportation,conversion and utilization and resource utilization,this paper summarized and analyzed the energy consumption and pollutant emission sources of these five links,combined with the US Environmental Protection Agency’s AP-42 method and IPCC method,to calculate total pollutant discharge and emission factors,where the emission factors were corrected by conversion efficiency.At the same time,uncertainty analysis is performed about CO2 and SO2 emissions.The results showed that CO2 emissions were 3.657 billion tons,and emission reductions were 61 million tons,and SO2 emissions were 4,844,500 tons,and emission reductions were 10.3595 million tons in 2015.

FLEXURAL WAVE DISPERSION IN MULTI-WALLED CARBON NANOTUBES CONVEYING FLUIDS

Motivated by the great potential of carbon nanotubes for developing nanofluidic devices, this paper presents a nonlocal elastic, Timoshenko multi-beam model with the second order of strain gradient taken into consideration and derives the corresponding dispersion relation of flexural wave in multi-walled carbon nanotubes conveying fuids. The study shows that the moving flow reduces the phase velocity of flexural wave of the lowest branch in carbon nanotubes. The phase velocity of flexural wave of the lowest branch decreases with an increase of flow velocity. However, the effects of flow velocity on the other branches of the wave dispersion are not obvious. The effect of microstructure characterized by nonlocal elasticity on the dispersion of flexural wave becomes more and more remarkable with an increase in wave number.

Interface coupling effects of weakly nonlinear Rayleigh–Taylor instability with double interfaces

Taking the Rayleigh–Taylor instability with double interfaces as the research object,the interface coupling effects in the weakly nonlinear regime are studied numerically.The variation of Atwood numbers on the two interfaces and the variation of the thickness between them are taken into consideration.It is shown that,when the Atwood number on the lower interface is small,the amplitude of perturbation growth on the lower interface is positively related with the Atwood number on the upper interface.However,it is negatively related when the Atwood number on the lower interface is large.The above phenomenon is quantitatively studied using an analytical formula and the underlying physical mechanism is presented.

Acoustic characteristics of cold-seep methane bubble behavior in the water column and its potential environmental impact

The amount of methane leaked from deep sea cold seeps is enormous and potentially affects the global warming,ocean acidification and global carbon cycle.It is of great significance to study the methane bubble movement and dissolution process in the water column and its output to the atmosphere.Methane bubbles produce strong acoustic impedance in water bodies,and bubble strings released from deep sea cold seeps are called"gas flares"which expressed as flame-like strong backscatter in the water column.We characterized the morphology and movement of methane bubbles released into the water using multibeam water column data at two cold seeps.The result shows that methane at site I reached 920 m water depth without passing through the top of the gas hydrate stability zone(GHSZ,850 m),while methane bubbles at site II passed through the top of the GHSZ(597 m)and entered the non-GHSZ(above 550 m).By applying two methods on the multibeam data,the bubble rising velocity in the water column at sites I and II were estimated to be 9.6 cm/s and 24 cm/s,respectively.Bubble velocity is positively associated with water depth which is inferred to be resulted from decrease of bubble size during methane ascending in the water.Combined with numerical simulation,we concluded that formation of gas hydrate shells plays an important role in helping methane bubbles entering the upper water bodies,while other factors,including water depth,bubble velocity,initial kinetic energy and bubble size,also influence the bubble residence time in the water and the possibility of methane entering the atmosphere.We estimate that methane gas flux at these two sites is 0.4×10~6–87.6×10~6 mol/a which is extremely small compared to the total amount of methane in the ocean body,however,methane leakage might exert significant impact on the ocean acidification considering the widespread distributed cold seeps.In addition,although methane entering the atmosphere is not observed,further research is still needed to understand its potential impact on increasing methane concentration in the surface seawater and gas-water interface methane exchange rate,which consequently increase the greenhouse effect.

Transverse shear and normal deformation effects on vibration behaviors of functionally graded micro-beams

A quasi-three dimensional model is proposed for the vibration analysis of functionally graded(FG)micro-beams with general boundary conditions based on the modified strain gradient theory.To consider the effects of transverse shear and nor-mal deformations,a general displacement field is achieved by relaxing the assumption of the constant transverse displacement through the thickness.The conventional beam theories including the classical beam theory,the first-order beam theory,and the higher-order beam theory are regarded as the special cases of this model.The material proper-ties changing gradually along the thickness direction are calculated by the Mori-Tanaka scheme.The energy-based formulation is derived by a variational method integrated with the penalty function method,where the Chebyshev orthogonal polynomials are used as the basis function of the displacement variables.The formulation is validated by some comparative examples,and then the parametric studies are conducted to investigate the effects of transverse shear and normal deformations on vibration behaviors.

Research on Stealth Assistant Decision System of Submarine Voyage Stage

Stealth security has always been considered as an important guarantee for the vitality and combat effectiveness of submarines.In accordance with the stealth requirements of submarines performing stealth voyage tasks,this paper proposes a stealth assistant decision system.Firstly,the submarine stealth posture is acquired.A fuzzy neural network inference engine based on improved simplified particle swarm optimization is designed.The auxiliary decision-making scheme for state control and maneuver avoidance of submarine and its equipment is automatically generated.Secondly,the simulation and deduction of the assistant decision-making scheme are realized by the calculation modules of sound source level,propagation loss,and stealth situation.The assistant decision-making scheme and simulation result provide decision support for the commander.Thirdly,the simulation experiment platform of the submarine stealth assistant decision system is constructed.The submarine stealth assistant decision system described in this paper can quickly and efficiently produce assistant decision-making schemes,including submarine and equipment control and maneuver avoidance.The scheme is in line with the combat experience and the results of the pre-model simulation experiments,whereas the simulation deduction evaluates the rationality and effectiveness of the selected scheme.The submarine stealth assistant decision system can adapt to a complex battlefield environment in addition to rapidly and accurately providing assistance in decision-making.

Two-dimensional Boron Nitride for Electronics and Energy Applications

Two-dimensional(2D)boron nitride(BN),the so-called“white graphene,”has demonstrated a great potential in various fields,particularly in electronics and energy,by utilizing its wide bandgap(~5.5 eV),superior thermal stability,high thermal conductance,chemical inertness,and outstanding dielectric properties.However,to further optimize the performances from the view of structure-property relationship,the determinative factors such as crystallite sizes,layer thickness,dispersibility,and surface functionalities should be precisely controlled and adjusted.Therefore,in this review,the synthesis and functionalization methods including“top-down”and“bottom-up”strategies,and non-covalent and covalent modifications for 2D BN are systematically classified and discussed at first,thus catering for the requirements of versatile applications.Then,the progresses of 2D BN applied in the fields of microelectronics such as fieldeffect transistors and dielectric capacitors,energy domains such as thermal energy management and conversion,and batteries and supercapacitors are summarized to highlight the importance of 2D BN.Notably,these contents not only contain the state-of-the-art 2D BN composites,but also bring the current novel design of 2D BN-based microelectronic units.Finally,the challenges and perspectives are proposed to better broaden the scope of this material.Therefore,this review will pave an all-around way for understanding,utilizing,and applying 2D BN in future electronics and energy applications.

Flutter analysis of rotating beams with elastic restraints

The aeroelastic stability of rotating beams with elastic restraints is investigated.The coupled bending-torsional Euler-Bernoulli beam and Timoshenko beam models are adopted for the structural modeling.The Greenberg aerodynamic model is used to describe the unsteady aerodynamic forces.The additional centrifugal stiffness effect and elastic boundary conditions are considered in the form of potential energy.A modified Fourier series method is used to assume the displacement field function and solve the governing equation.The convergence and accuracy of the method are verified by comparison of numerical results.Then,the flutter analysis of the rotating beam structure is carried out,and the critical rotational velocity of the flutter is predicted.The results show that the elastic boundary reduces the critical flutter velocity of the rotating beam,and the elastic range of torsional spring is larger than the elastic range of linear spring.

Vibration of two-dimensional hexagonal boron nitride

The dynamic behavior of two-dimensional nanostructures is important to the future application of nano devices. The vibrational behaviors of single-layered hexagonal boron nitride(h-BN) are studied by molecular dynamics simulation and continuum plate model. The bending stiffness and Poisson’s ratios of h-BN along zigzag direction and armchair direction are calculated. H-BN is softer compared with graphene. The continuum plate model can predict the vibration of h-BN with four edge-clamped boundary conditions well. The electric fields in different directions have obvious influence on the vibration of h-BN. The natural frequency of h-BN changes linearly with the electric field intensity along the polarization direction. The natural frequency of h-BN decreases with the increase of electric field intensity along both positive and negative nonpolarization direction. While the natural frequency of h-BN increases with the increase of electric field intensity along both positive and negative transverse electric field.

六旋翼飞行器动态逆控制器设计

本文针对“X”型布局六旋翼飞行器的姿态控制问题,创建其简化数学模型,并结合PID与动态逆控制方法设计出一个姿态控制器。为了提高系统的鲁棒性,增加一个自适应矢量以补偿逆模型误差。仿真实验表明该控制器能达到快速响应并稳定跟踪指令的目的。