Analysis of the relationship between blood pressure variability and subtle cognitive decline in older adults

BACKGROUND Blood pressure variability(BPV)has been shown to be related to mild cognitive impairment and Alzheimer's disease in a number of studies.However,the relationship between BPV and subtle cognitive decline(SCD)has received minimal attention in this field of research to date and has rarely been reported.AIM To examine whether SCD is independently associated with changes in BPV in older adults.METHODS Participants were selected based on having participated in cognitive function evaluation and ambulatory blood pressure measurement at the Shanghai Sixth People's Hospital Affiliated with Shanghai Jiao Tong University School of Medicine between June 2020 and August 2022.The participants included 182 individuals with SCD as the experimental group and 237 with normal cognitive function as the control group.The basic data,laboratory examinations,scale tests,and ambulatory blood pressure test results of the two groups were analyzed retrospectively,and the relationship between SCD and BPV was subsequently evaluated.RESULTS Significant differences were observed between the two groups of participants(P<0.05)in terms of age,education level,prevalence rate of diabetes,fasting blood glucose level,24-h systolic blood pressure standard deviation and coefficient of variation,24-h diastolic blood pressure standard deviation and coefficient of variation.The scale monitoring results showed significant differences in the scores for memory,attention,and visual space between the experimental and control groups.Logistic regression analysis indicated that age,education level,blood sugar level,and BPV were factors influencing cognitive decline.Linear regression analysis showed that there was an independent correlation between blood pressure variation and SCD,even after adjusting for related factors.Each of the above differences was still significant.CONCLUSION This study suggests that increased BPV is associated with SCD.

The Relationship of Cavitation to the Negative Acoustic Pressure Amplitude in Ultrasonic Therapy

The relationship between the cavitation and acoustic peak negative pressure in the high-intensity focused ultrasound （HIFU） field is analyzed in water and tissue phantom. The peak negative pressure at the focus is determined by a hybrid approach combining the measurement with the simulation. The spheroidal beam equation is utilized to describe the nonlinear acoustic propagation. The waveform at the focus is measured by a fiber optic probe hydrophone in water. The relationship between the source pressure amplitude and the excitation voltage is determined by fitting the measured ratio of the second harmonic to the fundamental component at the focus, based on the model simulation. Then the focal negative pressure is calculated for arbitrary voltage excita- tion in water and tissue phantom. A portable B-mode ultrasound scanner is applied to monitor HIFU-indueed cavitation in real time, and a passive cavitation detection （PCD） system is used to acquire the bubble scattering signals in the HIFU focal volume for the cavitation quantification. The results show that： （1） unstable cavitation starts to appear in degassed water when the peak negative pressure of HIFU signals reaches 13.5 MPa; and （2） the cavitation activity can be detected in tissue phantom by B-mode images and in the PCD system with HIFU peak negative pressures of 9.0 MPa and 7.8 MPa, respectively, which suggests that real-time B-mode images could be used to monitor the cavitation activity in two dimensions, while PCD systems are more sensitive to detect scattering and emission signals from cavitation bubbles.

Preliminary Study on the Linear Relationship between the Internal Pressure Head of Rubber Dam Bags and Real-time Dam Height

The design operating conditions of rubber dams were analyzed,and it is found that the operating conditions are similar to the actual operating conditions of changes in the internal pressure ratio of a specific rubber dam bag in the process of filling and draining. Based on this,the linear relationship curve between the internal pressure head H0 and the real-time dam height H and its approximate analytical formula can be obtained,which can be used as a supplement and correction method for the measurement method of real-time dam height during rubber dam operation,and provides reference for rubber dam project managers.

5-16 A New Relationship for the Pressure Drop of Wire-wrapped Fuel Bundles

In the project of MeAWaT*, an innovative hollow pin is designed. For reactor design calculations, it is necessaryto predict the hydraulic losses in multi-rod fuel bundles accurately[1]. And there is a long history for the use of spiralwire to maintain the pins in their position in fuel assemblies of reactors[2]. In this paper, a series of computationalfluid dynamics (CFD) calculations are carried out on wire-wrapped pins, with constant pin length and differentwire pitches. A new correlation is proposed.

From Pressure-Volume Relationship to Volume-Energy Relationship: A Thermo-Statistical Model for Alveolar Micromechanics

The connective tissue fiber system and the surfactant system are essential and interdependent components of lung elasticity. Despite considerable efforts over the last decades, we are still far from understanding the quantitative roles of either the connective tissue fiber or the surfactant systems. Through thermo-statistic considerations of alveolar micromechanics, the author introduced a thermo-statistic state function “entropy” to analyze the elastic property of pulmonary parenchyma based on the origami model of alveolar polyhedron. By use of the entropy for alveolar micromechanics, from the logistic equation for the static pressure (P)-volume (V) curves including parameters a, b, c, and k (V - a = b/[1+ exp{-k (P - c)}]), a set of equations was obtained to define the internal energy of lungs (UL) and its corresponding lung volume (VL). Then, by use of parameters a, b, c, and k, an individual volume-internal energy (VL - UL) diagram was constructed from reported data in patients on mechanical ventilation. Each VL - UL diagram constructed was discussed that its minimal value Uo = c (a + b/2) and its shape parameter b/k represent quantitatively the energy of tissue force and the energy of surface force. Furthermore, by use of the VL - UL relationship, the hysteresis of lungs estimated by entropy production was discussed as dependent on the difference in the number of contributing pulmonary lobules. That is, entropy production might be a novel quantitative indicator to estimate the dynamics of the bronchial tree. These values obtained by combinations of parameters of the logistic P-V curve seem useful indicators to optimize setting a mechanical ventilator. Thus, it is necessary to develop easy tools for fitting the individual sigmoid pressure-volume curve measured in the intensive care unit to the logistic equation.

Tight gas production model considering TPG as a function of pore pressure,permeability and water saturation

Threshold pressure gradient has great importance in efficient tight gas field development as well as for research and laboratory experiments.This experimental study is carried out to investigate the threshold pressure gradient in detail.Experiments are carried out with and without back pressure so that the effect of pore pressure on threshold pressure gradient may be observed.The trend of increasing or decreasing the threshold pressure gradient is totally opposite in the cases of considering and not considering the pore pressure.The results demonstrate that the pore pressure of tight gas reservoirs has great influence on threshold pressure gradient.The effects of other parameters like permeability and water saturation,in the presence of pore pressure,on threshold pressure gradient are also examined which show that the threshold pressure gradient increases with either a decrease in permeability or an increase in water saturation.Two new correlations of threshold pressure gradient on the basis of pore pressure and permeability,and pore pressure and water saturation,are also introduced.Based on these equations,new models for tight gas production are proposed.The gas slip correction factor is also considered during derivation of this proposed tight gas production models.Inflow performance relationship curves based on these proposed models show that production rates and absolute open flow potential are always be overestimated while ignoring the threshold pressure gradients.

Interfacial energy and match of cold pressure welded Ag/Ni and Al/Cu

The technology of cold pressure welding was adopted to achieve the bonding of Al/Cu(limited soluble and forming compounds), Ag/Ni (hardly mutual soluble), and the relative state of interface was tested by HREM. The results indicate that stable interface is always corresponding to the low interfacial energy value; the stable interface is not coherent but partly-coherent because of the twisting of grain boundary caused by pressure, meanwhile existing dislocation. Namely, the interfacial match and other states under the condition of cold pressure welding are different from the situation that under the condition of thermal action. Moreover, theoretical analyses and calculation on the base of thermodynamics, crystallogeny, solid physics etc, were discussed.

A METHOD OF ESTIMATING TYPHOON CENTRAL WIND BASED ON SEA LEVEL PRESSURE OF THE TYPHOON YEARBOOK OF CHINA

Based on the Typhoon Yearbook data(1980-2000),some wind-pressure fitting relationships were established for different typhoon intensity at the different latitudes of the western North Pacific.As shown in validations with the 2001-2005 data,the relationships(namely,those between minimum sea level pressure(SLP) and maximum sustained wind near a typhoon center) are stable.They may be applied to correct the overestimated typhoon wind speeds in earlier years(1950-1979).Statistical analysis showed that the stronger the typhoon,the more stable this wind-pressure relationship is.Moreover,it is more stable at the lower latitude belt(10°N-30°N).On the basis of this result,a methodology of correcting typhoon's wind speeds and frequency in these years was put forward,and the climatological series were reconstructed of yearly total typhoon frequencies over the western North Pacific in 1950-1979 and indices were determined of destructive power of typhoons in the offshore regions of China.

基于跌坎压力自相似分布的明渠水深−流量关系推求

明渠流量计量是高效灌溉、合理分配水资源和进行用水有效管理的重要手段。跌水是常见的明渠水流上下游衔接的水利设施。当跌落水流不受跌坎下游水流影响时形成自由跌流,可用于明渠流量的精确计量。受自由跌流影响,跌坎断面水流由缓流向急流转变,压力分布显著偏离静水压力分布规律。而获得跌坎压力分布及其准确描述方程则正是明渠自由跌流流量公式推求的关键,其准确与否决定了利用跌流进行流量计量的精度。本文首先通过模型试验和数值计算对矩形明渠自由跌流的断面压力分布特征进行研究,而后利用理论推导建立了明渠跌流的水深−流量关系公式。研究发现,明渠跌水跌坎断面压力呈典型自相似分布规律,其无量纲压力值分布倾向于一条曲线,压力最大值为0.238he(he为跌坎水深),出现在竖向距跌坎0.209he水深处,并且压力自相似分布规律与明渠流量、渠道底坡和边壁糙率无关。在此基础上,结合幂函数和尾迹函数提出了描述跌坎断面压力分布的函数方程,并给出了最大压力和最大压力位置的计算公式,然后根据动量方程和流量连续方程推求了明渠自由跌流的流量计算公式。最后,对本文和其他研究者提出的流量计算公式采用试验数据进行了对比分析,结果表明:本文提出的流量公式在明渠流量为5~100 L/s,底坡为–0.0112~0.0534、糙率为0.0930~0.0193的研究范围内,具有更高的精度和适用性,计算误差在±5%之内,可适用于该流量、底坡和边壁糙率范围内矩形明渠自由跌流的流量精确计算。本文研究结果对于利用自由跌流进行明渠流量计量提供了理论与技术支撑,具有重要的工程应用价值。

基于BP神经网络的胶结砂砾石应力-应变关系预测

在前期宏观试验基础之上,采用离散元模拟和BP神经网络相结合的方法获取不同胶凝材料掺量和围压下胶结砂砾石的应力-应变关系。根据前期胶凝材料掺量分别为20、40、60、80、100 kg/m3的胶结砂砾石三轴排水剪切试验结果,开展离散元数值模拟。以试验数据为学习样本,开展BP神经网络模型训练,预测胶凝材料掺量分别为30、50、70、90 kg/m3的胶结砂砾石应力-应变关系,并将预测结果和离散元模拟结果进行对比。研究结果表明,BP神经网络能够实现胶结砂砾石应力-应变关系的预测,并在较低围压下具有较好的精度。

血压与心血管疾病的关系:一项孟德尔随机化研究

血压在各种心血管疾病的发展和预后中起着至关重要的作用,但受限于传统流行病学的研究方法,并不能明确血压与心血管疾病之间的因果关系。孟德尔随机化(MR)研究是近年兴起的研究因果关系的方法。本项研究利用两样本MR方法探究血压(舒张压/收缩压)与常见心血管疾病之间的因果关系。结果显示,舒张压与脑动脉瘤(OR=2.00,95%CI:1.58~2.52,P=5.92×10^(-9)),主动脉瘤(OR=2.04,95%CI:1.69~2.46,P=9.02×10^(-14)),胸主动脉瘤(OR=2.21,95%CI:1.61~3.05,P=1.26×10^(-6)),房颤(OR=1.26,95%CI:1.16~1.37,P=4.74×10^(-8)),心肌梗死(OR=1.89,95%CI:1.68~2.13,P=1.06×10^(-25)),心衰(OR=1.34,95%CI:1.23~1.45,P=1.12×10^(-12))和缺血性中风(OR=1.60,95%CI:1.47~1.74,P=2.77×10^(-29))之间均存在显著的因果关系。收缩压与脑动脉瘤(OR=2.04,95%CI:1.62~2.57,P=1.76×10^(-9)),主动脉瘤(OR=1.29,95%CI:1.06~1.56,P=9.37×10^(-3)),房颤(OR=1.29,95%CI:1.18~1.42,P=3.55×10^(-8)),心肌梗死(OR=1.89,95%CI:1.68~2.13,P=8.09×10^(-26)),心衰(OR=1.37,95%CI:1.27~1.47,P=2.01×10^(-16))和缺血性中风(OR=1.49,95%CI:1.37~1.62,P=1.59×10^(-20))之间也存在显著的因果关联。遗传变异预测的收缩压和舒张压与心肌梗死、房颤、心衰和缺血性中风的风险升高显著相关,并大幅度增加动脉瘤的风险。及早发现和积极管理高血压,对心血管健康至关重要。降低血压是预防和控制心血管疾病的重要措施之一。通过调整生活方式和药物治疗,可以有效控制血压,减少心血管疾病的风险。

Al/Hf ratio-dependent mechanisms of microstructure and mechanical property of nearly fully dense Al—Hf reactive material

This study proposed three types of Al—Hf reactive materials with particle size ratios(a),which were almost completely dense(porosity of<5.40%)owing to their preparation using hot-pressing technology.Microstructure characteristics and phase composition were analyzed,and the influence of particle size ratios on dynamic mechanical behavior and damage mechanism were investigated.The prepared sample with a=0.1 exhibited continuous wrapping of the Hf phase by the Al phase.Hf—Hf contact(continuous Hf phase)within the sample gradually increased with increasing a,and a small amount of fine Hf appeared for the sample with a=1.The reactive materials exhibited clear strain-rate sensitivity,with flow stressσ0.05and failure strainεfincreasing approximately linearly with increasing strain rate.ε.It is found that the plastic deformation of the material increased with increasing strain rate.As a increased from 0.1 to 1,the flow stress gradually increased.Impact failure of the material was dominated by ductile fracture with a large Al phase plastic deformation band for lower a,while brittle fracture with crushed Hf particles occurred at higher a.Finally,a constitutive model based on BP neural network was proposed to describe the stress-strain relationships of the materials,with an average relative error of 2.22%.

基于冲击Hugoniot关系的爆压性质和不确定度量化

精确评估炸药冲击Hugoniot参数的可信区间,有效量化冲击起爆、状态方程等唯象模型的不确定度,提高模型的鲁棒性和可靠性,会极大地降低爆压标定的成本。利用线性回归拟合方法得到冲击Hugoniot参数,采用参数估计法推导出Hugoniot参数的置信区间,使用国内试验数据确认方法的有效性。在合理假设的基础上,结合Chapman-Jouguet理论和冲击Hugoniot关系,导出爆压与装药厚度、冲击波走时、初始密度、Hugoniot斜率和0-压声速之间的函数关系式。分别用对数正态分布和Beta分布表征输入不确定度,通过Rosenblatt变换将输入不确定度转化成相互独立的标准正态分布,使用自适应基函数多项式混沌不确定度传播量化方法,给出了爆压的概率密度函数和置信区间。研究结果表明,爆压与样品厚度、爆轰走时、爆速具有拟单调性,在特殊前提下证实了前人的判断。应用于PBX9502炸药,发现给出的置信区间较宽,与试验专家的先验论断吻合。该研究发展了一套有效量化爆轰不确定度的传播量化方法,为发展可信、强预测能力爆轰模拟软件提供了技术支撑。

不同剂量异丙肾上腺素对家兔动脉血压及心脏损伤的影响探讨

目的:探讨与分析不同剂量异丙肾上腺素对家兔动脉血压及心脏损伤的影响。方法:研究时间为2022年4月—2023年2月,健康成年雄性家兔18只随机平分为低剂量异丙肾上腺素组、高剂量异丙肾上腺素组与对照组,每组6只。低剂量异丙肾上腺素组、高剂量异丙肾上腺素组家兔每日背部皮下注射0.1ml/kg与0.4ml/kg的异丙肾上腺素100μl,1次/d;对照组在同样位置注射无菌生理盐水100μl,1次/d,持续应用14d,检测家兔中心动脉压变化情况。结果:低剂量、高剂量异丙肾上腺素组处理第7天、第14天的平均动脉压、血清肌酸激酶、乳酸脱氢酶含量都高于对照组(P<0.05),高剂量异丙肾上腺素组也高于低剂量异丙肾上腺素组(P<0.05)。低剂量、高剂量异丙肾上腺素组处理第7天、第14天的维持窦性节律时间均短于对照组(P<0.05),且高剂量异丙肾上腺素组短于低剂量异丙肾上腺素组(P<0.05)。低剂量、高剂量异丙肾上腺素组处理第14天的心脏组织Caspase-3、Bcl-2蛋白相对表达水平高于对照组(P<0.05),且高剂量异丙肾上腺素组高于低剂量异丙肾上腺素组(P<0.05)。结论:高低剂量的异丙肾上腺素均可降低家兔维持窦性节律时间,提高血清肌酸激酶、乳酸脱氢酶含量,促进其心脏组织Caspase-3、Bcl-2蛋白的表达,且存在量效关系,这为异丙肾上腺素诱导家兔心肌损伤模型的构建提供机制及理论依据指导。

基于协同优化的耐压柱壳多学科多目标优化

为提高耐压柱壳的设计效率和结构性能,本文基于多学科设计优化思想,进行了耐压柱壳多学科设计优化的学科分解,确定了耐压柱壳多学科优化设计的设计参数,明确了设计变量间的耦合关系,设计了耐压柱壳参数化分析流程,进行了设计变量灵敏度分析。在利用响应面模型建立了具有较高拟合精度耐压柱壳近似模型的基础上,以质量排水量比和极限载荷为目标函数,建立了基于协同优化方法的耐压柱壳多学科多目标优化模型,在确定了系统层和学科层的优化求解方法基础上,设计了基于协同优化的耐压柱壳多学科多目标优化框架,进行了优化的求解工作,得到了优化方案。与初始方案的对比表明:所得到的Pareto解集中,部分方案在2个目标函数上均得到了优化,验证了优化框架的有效性。

磷酸酯类极压抗磨剂构效关系的分子模拟研究

为从分子水平上研究磷酸酯类极压抗磨剂分子结构参数与其极压抗磨性能的关系,以磷酸三乙酯为模型化合物,采用分子模拟方法研究了磷酸三乙酯分子与Fe(110)表面的作用机理,发现磷酸酯分子主要通过P=O基团中O原子提供的电子与Fe表面发生吸附作用。采用分子模拟方法计算了不同磷酸酯类极压抗磨剂分子的结构参数,采用遗传函数算法初步建立了磷酸酯类极压抗磨剂的分子结构参数与极压性能、抗磨性能的定量关系方程。对该关系方程进行内检验和外检验,结果表明:所建方程具有较好的预测能力;由该方程可知,影响磷酸酯类极压抗磨剂分子极压、抗磨性能的主要结构参数包括P=O或P=S基团中O或S原子所带的电荷量、C—O键或C—S键的键能以及添加剂的S含量。

Study on Interaction Relationship for Submarine Pipeline with Axial Corrosion Defects

Corrosion is one of the main reasons to cause the operation accident of submarine oil and gas transmission pipelines. As the major corrosion pattern in submarine pipelines, the effects of corrosion clusters consisting of the adjacent corrosion defects on failure pressure are investigated through non-linear large-deformation finite element method. Typically, the failure behavior and limit strength of submarine pipeline with axial groove- groove corrosion defect pair exposed to interhal pressure are analyzed. The effects of corrosion depth and axial spacing between a pair of corrosion defects on failure pressure are concluded. An interaction relationship for corrosion defects in pipelines, as well as prediction formulations for assessing the remaining strength of corroded pipelines are proposed. The expressions based on the proposed interaction relationship give more accurate results than the methods used in the existing design guidelines.

Distributions and Relationships of CO_2,O_2,and Dimethylsulfide in the Changjiang(Yangtze) Estuary and Its Adjacent Waters in Summer

The distributions and relationships of O_2, CO_2, and dimethylsulfide (DMS) in the Changjiang (Yangtze) Estuary and its adjacent waters were investigated in June 2014. In surface water, mean O_2 saturation level, partial pressure of CO_2 (pCO_2), and DMS concentrations (and ranges) were 110% (89%–167%), 374μatm (91–640 μatm), and 8.53 nmol L^(-1) (1.10–27.50 nmol L^(-1)), respectively. The sea-to-air fluxes (and ranges) of DMS and CO_2 were 8.24 μmol m^(-2)d^(-1) (0.26–62.77 μmol m^(-2)d^(-1)), and -4.7 mmol m^(-2)d^(-1) (-110.8-31.7 mmol m^(-2)d^(-1)), respectively. Dissolved O_2 was oversaturated, DMS concentrations were relatively high, and this region served as a sink of atmospheric CO_2. The pCO_2 was significantly and negatively correlated with the O_2 saturation level, while the DMS concentration showed different positive relationships with the O_2 saturation level in different water masses. In vertical profiles, a hypoxic zone existed below 20 m at a longitude of 123?E. The stratification of temperature and salinity caused by the Taiwan Warm Current suppressed seawater exchange between upper and lower layers, resulting in the formation of a hypoxic zone. Oxidative de-composition of organic detritus carried by the Changjiang River Diluted Water (CRDW) consumed abundant O_2 and produced additional CO_2. The DMS concentrations decreased because of low phytoplankton biomass in the hypoxic zone. Strong correlations ap-peared between the O_2 saturation level, pCO_2 and DMS concentrations in vertical profiles. Our results strongly suggested that CRDW played an important role in the distributions and relationships of O_2, CO_2, and DMS.

能源介质储存容器内部爆炸场景下爆破片动态响应特性

天然气、氢气等储存容器在容器壁面上设置有爆破片安全装置,但国内外研究多关注爆破片静态超压爆破响应,而对储存容器内部爆炸风险场景下爆破片动态响应的关注较少。采用甲烷空气混合物爆炸实验方法,开展了爆破片在动态爆炸超压下的爆破实验,研究了升压速率对爆破片爆破压力的影响。结果表明:动态爆炸超压下爆破片爆破压力高于静态爆破压力。随升压速率的增加,爆破压力增加。定义超压倍数为动态爆破压力与静态爆破压力之比。对正拱开缝型爆破片,当升压速率由2.26 MPa/s增至65.64 MPa/s时,超压倍数由1.18增至2.21;对反拱带槽型爆破片,当升压速率由2.73 MPa/s增至62.05 MPa/s时,超压倍数由1.09增至1.45。反拱带槽爆破片抵抗动态超压的能力强于正拱开缝型爆破片。拟合得到了超压倍数与升压速率的关系式。分析认为,爆破片膜片在承载时的结构变形以及膜片材料的应力应变关系差异,是静态与动态超压下爆破片具有不同响应特性的原因。

贸易政策不确定性与产业结构升级

在全球贸易保护主义抬头的背景下,提升产业链现代化水平、解决“卡脖子”难题对缓解贸易冲突、实现高质量发展至关重要。选取2000—2020年我国31个省份(未包含港澳台地区)面板数据作为研究样本,实证考察以贸易政策不确定性为代表的国家经济转型的宏观变量对产业结构升级的影响。研究发现:贸易政策不确定性对产业结构升级具有双重的动态作用,能在抑制产业结构升级的同时,产生创造性破坏效应,倒逼产业结构升级,最终致使贸易政策不确定性与产业结构升级呈现“U”型关系。区域异质性检验发现:贸易政策不确定性对产业结构升级的影响在北方地区、中部地区、低创新能力地区及低金融发展水平地区更大。机制检验发现:贸易政策不确定性通过抑制地区科技创新能力发展和促进劳动力聚集,作用于产业结构升级并与之呈现“U”型关系。因此,政府部门应正确认识政策不确定性在短期内造成的“阵痛”现象,优化进口贸易结构、消除非关税障碍,大力推动科技创新与劳动力聚集,因地制宜制定产业发展战略目标,助力我国产业发展。