Going straight for the gut:gut-brain axis pathology and treatment of Parkinson's disease

This perspective focuses on the recent literature regarding the role of the gut-brain axis(GBA) in fecal microbiota transplantation(FMT) and stem cell therapy(SCT) in Parkinson's disease(PD).PD is the second most common neurodegenerative disease in the United States,yet therapies remain limited.Current research suggests that the GBA may play a role in the pathogenesis of PD.GBAbased FMT as well as SCT offer promising new avenues for PD treatment.Pro bing the interactions between FMT and SCT with the GBA may reveal novel therapeutics for PD.

Industrial utilization of arsenic-containing gold dressing tailings as pellet prepared by straight grate process

The utilization of arsenic-containing gold dressing tailings is an urgent issue faced by gold production companies worldwide.The thermodynamic analysis results indicate that ferrous arsenate(FeAsO_(4)),pyrite(FeS_(2))and sodium cyanide(NaCN)in the arsenic-containing gold metallurgical tailings can be effectively removed using straight grate process,and the removal of pyrite and sodium cyanide is basically completed during the preheating stage,while the removal of ferrous arsenate requires the roasting stage.The pellets undergo a transformation from magnetite to hematite during the preheating process,and are solidified through micro-crystalline bonding and high-temperature recrystallization of hematite(Fe_(2)O_(3))during the roasting process.Ultimately,pellets with removal rates of 80.77% for arsenic,88.78% for sulfur,and 99.88% for cyanide are obtained,as well as the iron content is 61.1% and the compressive strength is 3071 N,meeting the requirements for blast furnace burden.This study provides an industrially feasible method for treating arsenic-containing gold smelting tailings,benefiting gold production enterprises.

The world's longest straight road

Activity 1.Think about the following questions and write down your answers before reading the text.1.If you had the chance to travel on the longest straight road in the world,what would be the first thing you would do?2.Do you think having such a long straight road has more advantages or disadvan⁃tages?And why?

Related mechanisms and research progress in straight back syndrome

Despite the high prevalence of straight back syndrome(SBS),there is still limited research on this condition,posing challenges for effective diagnosis and treatment.The disease has been known for a long time,but there have been few related studies,which mostly consist of case reports.These studies have not been systematically summarized,making it difficult to meet the current needs of diagnosis and treatment.This article summarized the existing literature and comprehensively reviewed the diagnosis,pathogenesis,treatment,and research status of mitral valve prolapse related to SBS.We specifically emphasized the mechanisms and prognosis of SBS combined with mitral valve prolapse and discussed the latest research progress in this disease.

Measuring tree stem diameters and straightness with depth-image computer vision

Current techniques of forest inventory rely on manual measurements and are slow and labor intensive.Recent developments in computer vision and depth sensing can produce accurate measurement data at significantly reduced time and labor costs.We developed the ForSense system to measure the diameters of trees at various points along the stem as well as stem straightness.Time use,mean absolute error(MAE),and root mean squared error(RMSE)metrics were used to compare the system against manual methods,and to compare the system against itself(reproducibility).Depth-derived diameter measurements of the stems at the heights of 0.3,1.4,and 2.7 m achieved RMSE of 1.7,1.5,and 2.7 cm,respectively.The ForSense system produced straightness measurement data that was highly correlated with straightness ratings by trained foresters.The ForSense system was also consistent,achieving sub-centimeter diameter difference with subsequent measures and less than 4%difference in straightness value between runs.This method of forest inventory,which is based on depth-image computer vision,is time efficient compared to manual methods and less computationally and technologically intensive compared to Structure-from-Motion(SFM)photogrammetry and ground-based LiDAR or terrestrial laser scanning(TLS).

Straight and twisted Weyl nodal line phonons in Ho2CF2 material

Based on first-principles calculations, symmetry analysis and model construction, we predict that Ho2CF2hosts both straight and twisted Weyl nodal lines in its bulk phonon spectrum. We identify that the top two phonon bands entangle with each other, forming two straight Weyl nodal lines on the K–H and K′–H′paths at the Brillouin zone(BZ) boundary,and six twisted Weyl nodal lines within the BZ. All the Weyl nodal lines along the kz direction and across the entire BZ.The symmetry analysis indicates that these Weyl nodal lines are protected by the PT symmetry and crystal symmetry. The Berry phase and drumhead-like nontrivial surface states are calculated. We also construct a tight-binding model to describe these nodal lines. Our work provides an excellent material platform for exploring the fascinating physics associated with straight and twisted Weyl nodal line phonons.

Development and Performance Evaluation of Catalyst for Productive Ethylene Cracking Feedstock in Selective Hydrocracking of Straight Run Diesel Oil

The upgrading of diesel oil to produce ethylene rich cracking feedstock is an important and promising technical route to reduce the ratio of diesel to gasoline. In the present work, a hydrocracking catalyst suitable for selective hydrocracking of straight run diesel oil to produce high-quality ethylene cracking feedstock at low cost was developed, by optimizing the composition of catalyst support materials, using amorphous silicon aluminum and aluminum oxide with high mesopore content as the main support, and modified Y zeolite with excellent aromatic ring opening selectivity as the acidic component. The catalyst has in-depth characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N2-low temperature adsorption-desorption, NH3-temperature-programmed desorption, and IR techniques. And its catalytic cracking straight run diesel oil performance was evaluated. The results show that the prepared catalyst has high polycyclic aromatic hydrocarbon ring opening cracking selectivity. However, alkanes retained in diesel distillates can achieve the goal of producing more ethylene cracking feedstocks with low BMCI value under low and moderate pressure conditions. This work may shed significant technical insight for oil refining transformation.

Crossing Limit Cycles of Planar Piecewise Hamiltonian Systems with Linear Centers Separated by Two Parallel Straight Lines

In this paper, we have studied several classes of planar piecewise Hamiltonian systems with three zones separated by two parallel straight lines. Firstly, we give the maximal number of limit cycles in these classes of systems with a center in two zones and without equilibrium points in the other zone (or with a center in one zone and without equilibrium points in the other zones). In addition, we also give examples to illustrate that it can reach the maximal number.

Effect of Specific Verbal Instructions on the Identification of Pain Location during a Passive Straight Leg Raise Test

Musculoskeletal pain is common. Because pain is subjective, objectively describing it is crucial. However, pain assessment may cause distress in patients;therefore, physical therapists (PTs) should conduct these tests quickly and accurately. Simple and clear instructions are recommended for pain assessment. However, few studies have provided evidence to support this hypothesis. Correspondingly, this study aimed to confirm the effectiveness of specific verbal instructions for pain location during five consecutive Passive Straight Leg Raise (PSLR) tests. The 28 asymptomatic participants (age 27.4 ± 9.6 years) who provided informed consent received five consecutive PSLR tests: three without and two with specific verbal instructions to ascertain pain intensity, quality, and location. The participants drew pain locations on a body chart and described the pain intensity and quality after each test. All participants were interviewed regarding the differences they noted in the presence and absence of specific verbal instructions. Each pain location was classified into one of ten areas for statistical analysis. The proportion of participants who changed the pain location was compared between the tests using McNemar’s test, and the kappa coefficient was confirmed for consistency of pain location. There was a significant difference in the proportion of participants who changed their pain location between the second and third tests and from the third to the fourth test (McNemar’s test: p = 0.003). Kappa coefficients had low consistency (κ = 0.28) just after receiving the specific verbal instructions in the fourth test compared to the third test. Consistency improved in the fifth test (κ = 0.57);93% of the participants answered that the pain location had become clearer. This study revealed the effects of specific verbal instructions in identifying pain locations. This detailed information may help PTs provide appropriate treatment and contribute to reducing pain in clinical settings.

不同直插型基质对3种盆栽菊花生长的影响以及综合评价

为提高盆栽菊花(Chrysanthemum morifolium)扦插繁殖的成活率,提高菊花生产效率,以既有扦插基质又有营养基质的直插型基质代替传统栽培基质,设置了12种不同扦插基质,配合前期筛选的营养基质,扦插培养3种盆栽菊花‘辉煌’‘波尔多红’‘黄芙蓉’。测量其生长、生理以及光合指标,并利用主成分分析和隶属函数对不同直插型基质的盆栽菊花生长效果进行综合评价。结果表明:扦插基质为Z1(河沙)、Z2(珍珠岩)、Z3(蛭石)时,3个盆栽菊花品种的株高、茎粗、冠幅及花期等生长指标更具优势。‘辉煌’‘波尔多红’‘黄芙蓉’在Z2处理中的综合评价指数最高,分别为0.999、0.940、1.000,说明其育苗效果最好,可作为最佳直插型基质,其次为Z1、Z3处理。而扦插基质中,椰糠、稻壳和泥炭体积占比较大时,并不利于盆栽菊花的生长。

基于模糊快速滑模的农用牵引车辆直线路径跟踪控制

为解决无人驾驶牵引式农机在非结构化环境中作业时直线跟踪精度低、上线速度慢、抗干扰能力差等问题,提出了一种基于模糊快速滑模控制的农用牵引式车辆直线路径跟踪控制方法。首先利用车辆运动学模型与参考路径建立牵引车辆直线路径跟踪误差模型,并提出一种基于模糊参数整定的快速滑模直线路径跟踪方法,解决了滑模控制算法的控制器抖振与机具快速上线问题。通过Lyapunov稳定性分析可知,所设计控制方法可保证牵引机具跟踪参考路径,同时铰接角收敛至零。最后,基于Simulink仿真与实车试验对该控制方法的有效性与优越性进行测试。田间实车试验表明,使用本文控制方法时,拖车和挂车最大路径跟踪横向误差分别为0.11、0.12 m,拖车和挂车跟踪误差方差分别为0.0013、0.0015 m^(2);相较于传统基于等速趋近律设计的滑模控制器,上线时间提升约58%,最大跟踪误差减小约66%。

基于PSD的分离式长导轨直线度测量方法研究

利用分段拼接测量方法能够将PSD激光准直测量系统测量范围扩大,相较于传统长导轨直线度测量方法,该方法可同时适用于连续型导轨和分离式超长导轨的直线度测量。首先,在(-5~+5) mm测量范围内,通过激光干涉仪分别测得激光准直测量系统的接收靶在水平和竖直方向上的位移,误差均优于±(1μm+1%H)。然后,在40 m范围内与激光准直测量系统的直线度测量精度进行对比,二者水平方向直线度误差相差0.06 mm,竖直方向直线度误差相差0.13 mm。最后,在70 m分离式超长导轨上,测得水平方向直线度为0.50 mm,竖直方向直线度为0.53 mm。该方法可迅速定位和调整直线度误差极值点位置,能够较为有效地解决分离式超长导轨的直线度装配调试问题。

标准核燃料组件几何轮廓校准装置的研制

针对标准核燃料组件竖直状态下几何参数溯源需求,研制了一种标准核燃料组件几何轮廓校准装置。该装置以空间坐标测量为理念,利用多路接触式传感器作为轮廓测量采集单元,结合测量工作台高度位置获得轮廓坐标。通过直线度及扭转度测量与误差补偿,进一步提高了几何轮廓测量精度;并使用集成运动控制和专用测量软件,实现了标准核燃料组件几何轮廓参数(直线度、扭转度、垂直度、平行度)的自动检测。通过分析及实验验证,几何轮廓参数中直线度和平行度测量标准不确定度为0.01 mm,扭转度测量标准不确定度为0.007 mm,垂直度测量标准不确定度为0.017 mm,说明该装置能够满足标准核燃料组件的溯源需求。

下肢锻炼装置在青少年特发性脊柱侧凸患者术后直腿抬高训练中的应用效果研究

目的:分析应用团队自主研发的下肢锻炼装置对青少年特发性脊柱侧凸患者术后直腿抬高训练效果的影响,为临床实践提供依据。方法:采用方便抽样的方法,纳入2021年1月至2022年12月入住北京市某三级甲等医院骨科且符合纳入和排除标准的青少年特发性脊柱侧凸患者为研究对象,共计119例,按随机数字表法分为实验组62例、对照组57例。对照组使用传统的宣教方法,责任护士指导并督促患者进行直腿抬高训练;实验组在此基础上,责任护士使用下肢锻炼装置对患者进行直腿抬高训练的指导和督促,比较两组研究对象直腿抬高训练的完成情况及效果。结果:实验组的直腿抬高训练完成率及准确率更高,患者术后首次排气时间更短,患者功能锻炼满意度更高,差异均有统计学意义(P<0.05)。结论:下肢锻炼装置能够明显提高青少年特发性脊柱侧凸患者术后直腿抬高训练的完成率及准确性,促进患者术后胃肠功能恢复,有效提高患者满意度。

基于直线检测的航向角误差校正方法

提出了一种基于直线检测模型的多传感器数据融合航向角随机误差校正方法,旨在提高农林环境下低成本传感器组成的定位平台的精度。该方法通过调整直线检测阈值来实现状态的动态调整,以提高导航系统的鲁棒性和精确性。再将多传感器数据通过卡尔曼滤波融合,实现航向角随机误差的校正。试验结果表明,该方法在不同路径和速度下能有效降低航向角误差提高定位精度。在直线行进试验中,本方法的定位精度保持在5cm以内,航向角误差在5°以内。在矩形行进试验中,本方法的轨迹与差分RTK方法相近,平均误差仅为2.7cm,标准差为3.9cm。这一航向角校正方法为农业机械和车辆环境中的自主操作提供了有力支持。它能够适应不同的环境条件,提高导航系统的性能和测量准确性。

清水冲刷下顺直河道交错边滩演变过程试验研究

为进一步认识清水冲刷下顺直河道交错边滩的演变过程,基于长江中游典型边滩形态参数,采用概化水槽试验对不同流量条件下的交错边滩纵向、横向和平面冲淤变化进行了研究。结果表明:试验工况下,纵向上,沿程呈冲刷态势,流量越大,冲深越大(流量为215 L/s的深泓平均冲深约是流量为46.71 L/s的2.1倍),且大流量下深泓纵向比降变缓;横向上,边滩侧以冲刷为主,冲刷最大的位置在滩边附近,其它部位则呈冲刷—淤积—冲刷的变化规律(如流量为215 L/s时,2#断面边滩以外部分(0,2]h平均冲深约3.5 cm、(2,12]h平均淤高约0.5 cm、(12,21]h平均冲深约0.7 cm);平面上,边滩整体下移,变得细长,淤积主要发生在边滩下游1m范围内。此外,上游异岸边滩的存在初期会促使下游边滩淤积,而后加深下游边滩的冲刷,且对边滩坡脚影响最大。

黄土基坑斜直桩支护结构受力及变形特性模型试验研究

为深入探究斜直桩支护的工作机理及变形特性,通过模型试验对比斜直桩和传统支护在开挖和降雨阶段桩顶位移、桩身弯矩及坑外沉降变化规律。研究结果表明:斜直桩受力及变形均小于悬臂和双排直桩,其极限挖深更大,对周边环境影响更小,其中内斜直支护性能最优。部分直桩改为斜桩可使受力更合理,除了受到弯剪还有拉压,有效提高支护刚度。降雨阶段下支护结构受力及变形增幅较开挖更大,还会引发土体塌陷、坑内外土体表面开裂等破坏。研究结果可为斜直桩黄土基坑施工风险防控提供参考。

侧深施肥直斜偏置式免耕播种开沟器设计与试验

采用侧深施肥技术,施肥铲作业后播种带两侧土壤高度不一致,易加剧播种机横向偏摆,进而导致播种深度均匀性和播种横向一致性较差。为解决上述问题,该研究设计了一种直斜偏置式免耕播种开沟器。该开沟器主要由切土斜刃、挡土定位板、偏置推土板等组成,作业时滑切土壤并将其推移至肥沟一侧拓宽种沟,避免种子落至肥沟后位置过深,提高播种质量。通过离散元仿真试验,以前进阻力、肥沟回土深度、种沟回土深度为试验指标进行二因素五水平正交旋转组合试验,得到斜刃滑切角为37°、偏置角为15°时开沟器作业性能最好。在最优参数下与双圆盘式、尖角式开沟器进行田间作业性能对比试验,相对于双圆盘式和尖角式开沟器,直斜偏置式开沟器播种深度变异系数分别降低41.12%、19.41%;播种横向变异系数分别降低39.00%、28.41%;前进阻力分别降低7.26%、28.20%;作业后肥沟与种沟回土深度分别提高9.47%、13.68%和33.33%、7.14%。试验结果表明,该开沟器可以减小前进阻力,增加肥沟与种沟回土,提高播种深度均匀性和播种横向一致性,可为播种开沟器的设计提供参考。

内凹刀盘加工的直齿锥齿轮齿面接触分析

为了在国产数控弧齿锥齿轮机床上采用内凹刀盘加工直齿锥齿轮,对使用内凹刀盘加工直齿锥齿轮的原理和齿面接触分析(Tooth Contact Analysis,TCA)方法进行了研究。基于内凹刀盘的加工原理和结构特点,建立了内凹刀盘加工的直齿锥齿轮的齿面数学模型,给出了相应的齿面接触分析方法;编写齿面接触分析程序,计算得到了齿轮副的接触斑点和传动误差曲线;通过实际的切齿加工和接触斑点检验,验证了齿面数学模型以及TCA方法的正确性。研究为锥齿轮加工参数及刀具参数的确定与啮合质量控制提供了理论依据。

基于稀疏编码的复杂机械振动信号盲分离方法

复杂机械振动信号激励源较多,故源信号之间互为相关源,且较难满足统计独立特性,导致传统盲源分离方法分离效果不佳。对此,提出一种基于信号稀疏编码的机械振动信号盲分离方法。盲源分离的关键在于对混合矩阵的精确估计,然而机械振源中相关成分的存在严重影响混合矩阵的估计。对此,首先对观测信号进行短时傅里叶变换,增加信号稀疏性;然后利用稀疏编码筛选出具备直线聚类特性的时频观测点,利用K均值(K-means)聚类法找到聚类中心;最后利用所提筛选规则找到估计的混合矩阵,重构出源信号。通过对往复压缩机故障数据的分析,验证了所提方法有效性。