Determinants of Blood Pressure Variability in Individuals with Essential Hypertension: A Survey-Based Study

Background: Blood pressure variability (BPV) in hypertensive patients is implicated as a remarkable feature leading to additional cardiovascular complications. The aim of the study was to identify the determinants influencing BPV among patients with essential hypertension seen at the Cardiology department of the faculty of medicine, University of Alexandria, Egypt. Methods: This was a descriptive cross-sectional hospital-based study conducted from August 2019 to November 2019. All the eligible patients were made to fill out a standard questionnaire to obtain family and personal clinical history and undergo routine physical examination, laboratory tests and 24-hour ambulatory blood pressure monitoring. BPV was summarized as the standard deviation (SD) of all-day systolic and diastolic BP in both normal patients (with SD 11) and abnormal patients (with SD ≥ 11). Results: Out of a total of 114 patients, 18 (15.8%) non-hypertensive patients were included in the control group and the remaining 96 (84.3%) were classified based on the degree of hypertension. BPV in all these patients was found to be significantly related to the male gender, a mild or moderate degree of hypertension, high prevalence of non-dipping, diabetes, use of beta-blockers as antihypertensive medication, heart rate variability, BMI, and increased day-time variability. Conclusion: Variability in blood pressure influenced by different intrinsic and extrinsic factors plays an important role in the management of hypertension. In order to reduce the burden of disease and for a better quality of life for hypertensive patients, it is important that physicians start considering lowering BPV in addition to reducing physiological BP levels.

Determinants of High Blood Pressure and Quality of Management in Three Regions of Benin

Objective: The aim of this work was to determine the prevalence, associated factors and quality of high blood pressure (HBP) management in three regions of Benin in 2015. Methodology: This was a cross-sectional study, with two components. The first component included adults aged from 18 to 69 years, selected using a three-stage random sampling within the households. Data were collected thanks to the French version of the WHO STEPS instrument. Anthropometric data, including blood pressure, capillary fasting glucose and total cholesterol were measured according to standard procedures. The second component included Public Health Centers (PHC) selected by a random stratified multi-stage sampling. Data were collected on the structures and the processes of HBP management using the standardized tool for assessing the capacities of management of non-communicable diseases in peripheral health centers provided by the World Health Organization. Results: A total of 4816 participants were included in the first component. The mean age was 35.8 ± 12.7 years. The weighted prevalence of HBP was 27.9% (95% Confidence Interval (CI) [25.6 - 30.2]). It was higher in the 60 - 69 years compared to the lower age groups (Adjusted Odd-ratio (ORa) = 5;95% CI [3.9 - 6.5)]). HBP was positively associated with urban residence (ORa = 1.26;95% CI [1.24 - 1.28]), obesity (ORa = 1.46;95% CI [1.43 - 1.50]), hyperglycemia (ORa = 1.13;95% CI [1.10 - 1.15)]) and hypercholesterolemia (ORa = 1.64;95% CI [1.59 - 1.70)]). A total of 27 PHC were included in the second component. Taking blood pressure and other anthropometric measurements was not routine in PHC. Several essential medicines were not available in the PHC. A low level of community involvement in the management of HBP was noted. Conclusion: This study confirms the high prevalence of HBP and shows inadequacies in its management in the targeted PHC. More appropriate prevention and control measures for HBP should be implemented.

Impact Analysis of Solar Irradiance Change on Precision Orbit Determination of Navigation Satellites

Solar radiation pressure is the main driving force and error source for precision orbit determination of navigation satellites.It is proportional to the solar irradiance,which is the"sun constant".In regular calculation,the"solar constant"is regard as a constant.However,due to the existence of sunspots,flares,etc.,the solar constant is not fixed,the change in the year is about 1%.To investigate the variation of solar irradiance,we use interpolation and average segment modeling of total solar irradiance data of SORCE,establishing variance solar radiation pressure(VARSRP)model and average solar radiation pressure(AVESRP)model based on the built solar pressure model(SRPM)(constant model).According to observation data of global positioning system(GPS)and Beidou system(BDS)in 2015 and comparing the solar pressure acceleration of VARSRP,AVESRP and SRPM,the magnitude of change can reach 10-10 m/s^2.In addition,according to the satellite precise orbit determination,for GPS satellites,the results of VARSRP and AVESRP are slightly smaller than those of the SRPM model,and the improvement is between 0.1 to 0.5 mm.For geosynchronous orbit(GEO)satellites of BDS,The AVESRP and VARSRP have an improvement of 3.5 mm and 4.0 mm,respectively,based on overlapping arc,and SLR check results show the AVESRP model and the VARSRP model is improved by 2.3 mm and 3.5 mm,respectively.Moreover,the change of inclined geosynchronous orbit(IGSO)satellites and medium earth orbit(MEO)satellites is relatively small,and the improvement is smaller than 0.5 mm.

Solar Radiation Pressure Modeling and Application of BDS Satellites

Solar radiation pressure(SRP)model is the basis of high precise orbit determination and positioning of navigation satellites.At present,it is common to see the study of SRP model of BDS satellites.However,the establishment and application of a comprehensive analytical SRP model based on satellite physical parameters are rare.Different from other conservative forces and non-conservative forces,SRP is closely related to the satellite’s physical parameters and in-orbit state.On the basis of the physical mechanism of solar radiation,BDS satellite physical parameters,in-orbit attitude control mode,and so on,a comprehensive analytical model has been studied in this paper.Based on precise ephemeris and satellite laser ranging(SLR)data,the precision of a comprehensive analytical model has been verified.And the precision of orbit determination is at the decimeter level using this comprehensive analytical SRP model.According to the satellite conservation theorem of angular momentum and change of in-orbit telemetry parameters,the difference between a comprehensive analytical model and the actual in-orbit interference force has been analyzed and calculated.The addition of empirical items on the comprehensive analytical model has been proposed.SLR validations demonstrated that the orbit precision of BDS C08 and C10 can be achieved at 0.078 m and 0.084 m respectively.Compared with using the improved CODE empirical model,precision orbit accuracy of them has increased by 0.021 m and 0.045 m respectively.

A Study on the Dynamic Adjustment of Pressure Relief Gas Drainage Drilling in Mined-Out Areas

With the development of coal mine equipment mechanization, the wide application of “hole instead of roadway” technology greatly reduces the cost of gas control engineering, but puts forward higher requirements for the effect of gas drainage. At present, the drainage effect of coal mine inspection boreholes is mainly evaluated by the drilling field, but the flow rate and gas concentration of each borehole in the drilling field are not the same, which causes the gas drainage effect not to be correctly mastered. In the present study, the pressure relief drilling in the goaf of the working face of a typical multi-coal seam group high gas outburst mining area was taken as the research object. Through the newly developed portable drilling inspection device, the pure amount of drilling drainage was investigated, and the drilling design was dynamically adjusted. The enhancement of the goaf pressure relief gas control effect ensures the gas safety of the mining face. At the same time, this improves the gas extraction rate and reduces the emission of greenhouse gases. If the data from the borehole investigation can be transmitted in real time and analyzed in big data, the optimal extraction negative pressure can be predicted through a regression algorithm. Under the control of the negative pressure of each borehole by the actuator, the extraction system can have the function of intelligent judgment.

基于足底压力采集系统和压力中心的人体稳态判定方法

设计一种可穿戴的无线足底压力采集系统,并提出基于人体足底压力中心(CoP)的人体稳定状态判定方法.首先,使用该系统采集人体站立和行走时稳定和临界失稳状态下的足底压力数据;其次,通过足底压力信息获取人体稳定行走状态下CoP活动轨迹的区域和边界;最后,采集当前时刻的CoP,通过对当前时刻CoP与人体最大稳定CoP的轨迹区域及边界范围进行对比,实现对人体行走过程的稳定状态判定.结果表明,设计的可穿戴式无线足底压力采集系统具有可穿戴性,方便测量人体足底压力数据,实验验证了基于足底压力采集系统和压力中心的人体稳态判定方法有效.

头部血压连续检测算法研究与系统设计

血压参数是医学中疾病诊断和治疗的理论基础,在病理分析上具有十分重要的意义。而头部的血压变化不仅反映了头部血液供给是否充足,还体现着中枢神经系统的运行正常与否,因此对于头部血压的实时检测十分必要。针对头部血压测量困难的问题,该文提出一种基于光电容积脉搏波信号的可穿戴头部血压检测装置的设计方法。通过光环境传感器获取额头处的脉搏波信号。采用数字滤波器滤除额头处脉搏波信号的高频噪声、小波滤波法去除基线漂移、差分阈值法提取脉搏波波形特征,最终逐步回归拟合得出血压的计算模型。该系统采用可穿戴设计,经测试比较,与血压测量金标准的水银血压计听诊法测量血压具有较好的一致性。

志丹油田生产气油比测试探索与实践

生产气油比作为一项油田开发的重要资料,直接指导着油田地面工程的建设,由于众多历史及生产原因,目前,我们仅有部分探井的原始气油比,在油井生产过程中,当井底压力低于饱和压力后,原油中的天然气就会大量脱出,气油比则会增高,油田的开发进入中后期后生产气油比又会逐渐降低,因此原始气油比与目前的生产气油比差距较大[1],无论靠经验赋值或者乘系数估算,已不能满足油田地面工程建设需要,因此,快速、准确地测定生产气油比就显得尤为重要。

SF_(6)气体密度状态检测的快速算法

针对SF_(6)气体密度计算过程复杂的问题,提出了快速判定SF_(6)气体密度的算法,以220 kV气体绝缘金属封闭开关设备灭弧室外其他气室中SF_(6)气体密度状态的判定为例,介绍了该算法的基本原理和实现过程,并通过仿真计算比较了本文算法与现有算法的实时性,结果表明,本文算法实现过程简单,实时性大幅提高,可促进大范围、多节点SF_(6)气体密度状态统一集中检测的数字化电子设备的发展和应用。

HPLC法测定龙牡壮骨颗粒中甘草酸的含量

目的建立以高效液相色谱法(HPLC)测定龙牡壮骨颗粒中甘草酸含量的方法。方法采用Capcell pak C18(250 mm×4.6 mm,5μm)色谱柱,以乙腈-0.1%磷酸溶液(40∶60)为流动相,流速为1.0 mL/min,柱温为30℃,进样量为20μL,检测波长为254 nm。结果甘草酸铵在质量浓度为0.814~40.70μg/mL范围内与峰面积呈良好的线性关系[相关系数(r)≥0.999],平均加样回收率为96.52%[相对标准偏差(RSD)为0.85%]。结论此实验所建立的方法简便、准确、专属性强,测定结果重复性好,可为龙牡壮骨颗粒的质量控制提供依据。

大规模低轨星座的实时精密定轨技术

在全球导航卫星系统的支撑下,分析地面集中解算和星上自主解算精密定轨的优缺点,并将高精度轨道非保守力模型应用于星上实时自主定轨算法,实现运动学和动力学定轨的分离,对于需要频繁机动的低轨卫星精密定轨具有显著优势。结果表明,辐射光压和大气阻力非保守力物理模型计算的加速度精度约5 nm/s^(2);采用广播星历进行定轨解算可以达到0.8 m位置精度,低轨卫星速度误差约1.1 mm/s;采用实时精密星历,位置精度可以达到8.0 cm,卫星速度精度约0.1 mm/s。低轨卫星实时精密定轨和预报方法可有效支撑大规模低轨星座的导航功能实现。

ULTRA-HIGH PRESSURE DIFFERENTIAL THERMAL DETERMINATION OF DIASPORITE

Water plays an important role in the evolution history of the earth and the water in the deep earth mainly exists in minerals and magma melt. The study on ultra-high pressure differential thermal determination ofhydroites and their stability and mechanism of dehydration-dehydroxylation are significant for the understanding of the heat evolution history

有创血压监测换能器固定装置的设计及应用

目的 设计有创血压监测换能器固定装置,评价其应用效果。方法 换能器固定器包括调节带、固定底座、气泡水平尺三部分组成。选取2021年4月-2022年4月重症监护室行有创血压监测的患者60例,采用回顾性对照研究。对照组使用床旁固定杆固定压力传感器,试验组使用换能器固定装置将压力传感器固定进行测压。比较两组患者在不同体位血压监测的准确性、换能器移位或滑脱率、皮肤损伤及护士满意度情况。结果 两组患者不同角度的固定方法对有创血压和无创血压的影响,差异无统计学意义(P>0.05);试验组换能器脱落率为0、偏移(0.80±1.45) cm、医疗器械相关性压力损伤的发生率为0,显著低于对照组(P<0.05);护士总体满意度优于对照组。结论 有创血压监测换能器固定装置在确保测压准确性的同时,应用安全、便捷,护士满意度高。

包容型领导风格对降低新生代员工离职意向的影响——基于压力源的中介作用

基于自我决定理论和资源保存理论,从新生代员工的视角出发,探究包容型领导与其离职意向之间的关系,基于压力源的二维模型构建出双中介模型。共收集了341名企业新生代员工的有效样本数据,利用SPSS17.0以及AMOS26.0软件进行分析后得出如下结论:第一,包容型领导显著负向影响新生代员工的离职意向;第二,挑战性压力源在包容型领导与新生代员工离职意向的关系中起中介作用;第三,虽然阻碍性压力源不能在包容型领导和新生代员工离职倾向中起中介作用,但包容型领导能够负向影响阻碍性压力源,阻碍性压力源也能显著正向促进新生代员工的离职倾向。

导航卫星姿态和光压模型研究进展

不同导航系统中卫星的形状、材料、轨道设计和姿态控制模式等都不相同,在进行多系统数据联合处理时,要获得高精度的卫星轨道,需要区别对待不同类型卫星的姿态模型和光压模型。作为导航卫星所受量级最大的非保守力,国内外许多研究是围绕光压模型的建立与精化等方面来开展,以便建立最合适的模型,从而获取更高的定轨精度。目前的研究表明,新的Galileo以及北斗卫星采用与之前不同的姿态控制模式,适用的光压模型也不同。总结了目前比较通用的导航卫星姿态模型,尤其是官方最新公布的北斗卫星的姿态模型,详细介绍了卫星光压模型研究进展和近几年来新发射卫星光压模型以及其先验模型的构建方法,并分析了各个模型的优缺点和适应性。通过对目前导航卫星姿态以及光压模型的分析,提出在更高精度的定轨任务中有待改进的问题,为导航卫星尤其是新发射导航卫星精密定轨中的光压和姿态模型的选择和建立提供参考。

天然气压力能发电-制冰利用及运行效益评估研究

天然气压力能是一种新兴清洁能源,对其进行高效利用是节约能源、降低碳排放的有效手段。目前,天然气压力能回收利用中存在用能模式单一、评估指标片面以及评估方法缺乏等问题,导致天然气压力能利用率低,运行效益和系统不足无法被准确评估,行业发展受阻。首先,提出了天然气压力能综合利用方案,使用透平膨胀机回收压力能发电,降压过程中产生的冷能用于制冰,并加入太阳能热水系统提高出站气温度,提高能源利用效率。其次,基于分析模型并考虑经济性和环保性构建了压力能利用系统运行效益评估指标体系,对系统的运行状态进行全面、综合的评估。然后,建立了层次分析法-反熵权法综合评价模型,解决了指标之间相互影响、含义交叉的问题,提高了指标权重的判断精度。最后,通过对案例调压站评估可得,该调压站在运行中主要存在装置故障率高、系统稳定性差以及经济效益不显著等问题,评估结果验证了评估方法的有效性,为压力能利用系统的运行优化提供了理论支撑。

CLY-1型多参数智能测漏系统的研发

钻井工程中发生井漏不仅严重影响安全、快速、低成本钻井,而且会严重污染矿层,影响矿层产量。开展漏失层位置测定方法与仪器的研究,对复杂地质条件下的钻井生产具有十分重要的意义。本文阐述了研发的CLY-1型多参数智能测漏仪的构成、参数采集过程、处理原理、仪器的机械结构和测试情况。采用多参数智能测漏系统的下探管直接接到钻杆或钢丝绳下端投放入孔进行测试,孔内探管沿孔深对泥浆流速(流量)、井温、井压、自然伽马等4种参量进行数值化测试,并将采集数据按一定格式存储到存储器中。探管从井中取出后,与地面电脑系统连接,将采集的数据存到存储器上形成数字文档,向相关人员提供漏涌判层的依据。

偏磨抽油杆接箍力学性能及承载能力分析——以塔河油田抽油杆接箍断脱为例

针对塔河油田抽油杆接箍在采油生产过程中,易发生磨损现象,而导致抽油杆接箍断脱失效的问题。以直径为25 mm抽油杆,基体材料为35CrMo接箍为研究对象,考虑接箍壁厚受磨损程度的影响,应用有限元方法,开展抽油杆接箍在拉压载荷作用下受力分析和承载范围分析。通过拉压试验测试和数值模拟结果对比分析并验证数值方法可靠性基础上,开展了拉压载荷在20~250 kN下不同磨损量抽油杆接箍的力学性能分析。结果表明:等效应力和接触应力均随着载荷增大而增大,无磨损接箍在受力范围内均能满足应用要求。但由于接箍出现偏磨,其等效应力与接触应力分布对称性变差,且磨损严重时,其承载能力严重下降,断脱风险加大。

分析型光压模型在北斗导航卫星精密定轨中的应用

太阳辐射压摄动是导航卫星受到的最大非保守力,是精密定轨的主要误差源,目前一般使用扩展经验光压模型(ECOM)等经验模型应用于卫星的精密定轨,分析型光压模型物理背景清晰,更加适合在轨初期的精密定轨。文章分析了分析型光压模型在我国北斗高轨导航卫星中的应用。选取了约1个月的北斗地球静止轨道-6(GEO-6)和倾斜地球同步轨道-5(IGSO-5)卫星数据进行分析,其太阳辐射压摄动加速度在轨道的径向(R)、横向(T)和法向(N)3个方向分别约为10-7、10-7和10-8m/s2量级,将分析型光压模型和精密定轨输出的太阳辐射压加速度进行比较,GEO-6卫星径向和横向的差异在10-8m/s2量级,法向方向在10-9m/s2量级,相对误差在10%左右,对IGSO-5卫星,差异要小1/2左右,约为5%。以多模GNSS系统试验网络(MGEX)的轨道作为参考,直接使用分析型光压模型,GEO-6位置误差约为2.5 m, IGSO-5位置误差约为1.5 m,增加偏差和尺度因子标校参数后,位置精度分别提高到约0.5 m和0.1 m。结果表明:利用分析型光压模型,可以实现北斗GEO和IGSO卫星分米级的定轨精度。