Application of multi-algorithm ensemble methods in high-dimensional and small-sample data of geotechnical engineering:A case study of swelling pressure of expansive soils

Geotechnical engineering data are usually small-sample and high-dimensional,which brings a lot of challenges in predictive modeling.This paper uses a typical high-dimensional and small-sample swell pressure(P_(s))dataset to explore the possibility of using multi-algorithm hybrid ensemble and dimensionality reduction methods to mitigate the uncertainty of soil parameter prediction.Based on six machine learning(ML)algorithms,the base learner pool is constructed,and four ensemble methods,Stacking(SG),Blending(BG),Voting regression(VR),and Feature weight linear stacking(FWL),are used for the multi-algorithm ensemble.Furthermore,the importance of permutation is used for feature dimensionality reduction to mitigate the impact of weakly correlated variables on predictive modeling.The results show that the proposed methods are superior to traditional prediction models and base ML models,where FWL is more suitable for modeling with small-sample datasets,and dimensionality reduction can simplify the data structure and reduce the adverse impact of the small-sample effect,which points the way to feature selection for predictive modeling.Based on the ensemble methods,the feature importance of the five primary factors affecting P_(s) is the maximum dry density(31.145%),clay fraction(15.876%),swell percent(15.289%),plasticity index(14%),and optimum moisture content(13.69%),the influence of input parameters on P_(s) is also investigated,in line with the findings of the existing literature.

芍药苷通过调控PI3K/AKT/mTOR信号通路对盐敏感性高血压大鼠血压和血管内皮功能的影响

目的:探讨芍药苷对盐敏感性高血压(SSH)大鼠血压和血管内皮功能的影响及其相关作用机制。方法:将50只Dahl盐敏感大鼠随机分为正常对照组(Control组)、高盐组(SSH组)、芍药苷组(PF组)、磷脂酰肌醇-3-激酶(PI3K)/蛋白激酶B(AKT)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路激活剂组(740Y-P组)、芍药苷+740Y-P组(PF+740Y-P组),每组10只。各组大鼠进行4周给药干预。采用动物无创血压仪测量大鼠尾动脉收缩压、舒张压;酶联免疫吸附法(ELISA)测定大鼠血清内皮素-1(ET-1)、一氧化氮(NO)、血栓素B2(TXB2)水平;苏木精-伊红(HE)染色观察大鼠主动脉病理变化;免疫组织化学染色检测大鼠主动脉组织中内皮型一氧化氮合酶(eNOS)表达;蛋白质免疫印迹法(Western Blot)检测大鼠主动脉组织中PI3K/AKT/mTOR信号通路蛋白表达。结果:与Control组比较,SSH组和740Y-P组大鼠主动脉血管内皮不完整,部分血管内皮脱落,且内膜明显增厚、外膜有大量沉积物;PF组大鼠主动脉血管病理损伤较SSH组明显减轻;PF+740Y-P组大鼠主动脉血管病理损伤较740Y-P组明显减轻,但较PF组明显加重。与Control组比较,SSH组大鼠收缩压、舒张压、血清ET-1、TXB2水平均升高,血清NO水平降低(P<0.05);主动脉组织中eNOS表达水平降低,磷酸化(p)-PI3K/PI3K、p-AKT/AKT、p-mTOR/mTOR比值均升高(P<0.05)。与SSH组比较,PF组大鼠收缩压、舒张压、血清ET-1、TXB2水平均降低,血清NO水平升高(P<0.05);主动脉组织中eNOS表达水平升高,p-PI3K/PI3K、p-AKT/AKT、p-mTOR/mTOR比值均降低(P<0.05)。与PF组比较,PF+740Y-P组大鼠收缩压、舒张压、血清ET-1、TXB2水平均升高,血清NO水平降低(P<0.05);主动脉组织中eNOS表达水平降低,p-PI3K/PI3K、p-AKT/AKT、p-mTOR/mTOR比值均升高(P<0.05)。与740Y-P组比较,PF+740Y-P组大鼠收缩压、舒张压、血清ET-1、TXB2水平均降低,血清NO水平升高(P<0.05);主动脉组织中eNOS表达水平升高,p-PI3K/PI3K、p-AKT/AKT、p-mTOR/mTOR比值均降低(P<0.05)。结论:芍药苷可以有效降低SSH大鼠血压,并改善大鼠血管内皮功能,其作用机制可能与抑制PI3K/AKT/mTOR信号通路激活有关。

Pore-scale study of the pressure-sensitive effect of sandstone and its influence on multiphase flows

The pressure-sensitive effect on the pore structure of sandstone was investigated using X-ray computed micro-tomography and QEMSCAN quantitative mineral analysis. In a physical simulation study, we extracted the pore network model from digital cores at different confining pressures and evaluated the effect of pressure sensitivity on the multiphase displacement process. In both the pore network model and QEMSCAN scanning, the pore structure was observed to be damaged under a high confining pressure. Due to their different scales, the pores and throats exhibited inhomogeneous changes; further, the throats exhibited a significant variation compared to that exhibited by the pores. Meanwhile, the heterogeneity of the pore structure under the two aforementioned activities was aggravated by the elastic-plastic deformation of the pore structure.The pressure-sensitive effect increased the proportion of mineral particles, such as quartz(the main component of the core skeleton), and reduced the proportion of clay minerals. The clay minerals were originally attached to the pore walls or interspersed in the pores; however, as the pressure increased, the clay minerals accumulated in the pores resulting in blockage of the pores. While simulating the multiphase displacement process, increasing the confining pressure was observed to severely restrict the flowability of oil and water. This study promises to improve the efficiency of reservoir development in terms of oil and gas exploitation.

Simulation of the Pressure-Sensitive Seepage Fracture Network in Oil Reservoirs with Multi-Group Fractures

Stress sensitivity is a very important index to understand the seepage characteristics of a reservoir.In this study,dedicated experiments and theoretical arguments based on the visualization of porous media are used to assess the effects of the fracture angle,spacing,and relevant elastic parameters on the principal value of the permeability tensor.The fracture apertures at different angles show different change rates,which influence the relative permeability for different sets of fractures.Furthermore,under the same pressure condition,the fractures with different angles show different degrees of deformation so that the principal value direction of permeability rotates.This phenomenon leads to a variation in the water seepage direction in typical water-injection applications,thereby hindering the expected exploitation effect of the original well network.Overall,the research findings in this paper can be used as guidance to improve the effectiveness of water injection exploitation in the oil field industry.

microRNA基因多态性与血压钠钾反应性的相关性分析

目的探讨miRNA基因多态性与钠钾饮食干预后血压反应性之间的关系。方法本课题组2004年从中国陕西宝鸡7个村庄的124个家庭中招募514名参与者进行慢性盐负荷试验干预,包括3 d基线期、7 d低盐饮食、7 d高盐饮食和7 d高盐补钾饮食干预。纳入19个miRNA-SNP位点进行分析研究。结果在钠钾饮食干预过程中,受试者的血压在低盐期呈下降趋势,高盐期呈现上升趋势,而在高盐补钾后,血压则再次下降。在低盐期,miR-210-3p SNP rs12364149与收缩压反应性、舒张压反应性及平均动脉压反应性显著相关,miR-4638-3p SNP rs6601178与收缩压反应性显著相关,而miR-26b-3p SNP rs115254818与平均动脉压反应性显著相关。在高盐干预后,miR-26b-3p SNP rs115254818与收缩压反应性、舒张压反应性及平均动脉压反应性显著相关;miR-1307-5p SNP rs11191676、rs2292807与收缩压反应性及平均动脉压反应性密切相关;miR-4638-3p SNP rs6601178、miR-210-3p SNP rs12364149以及miR-382-5p SNP rs4906032、rs4143957与收缩压反应性存在显著关联性。此外,在给予补钾干预后miR-26b-3p SNP rs115254818与收缩压反应性、舒张压反应性及平均动脉压反应性关联显著;miR-1307-5p SNP rs11191676、rs2292807以及miR-19a-3p SNP rs4284505与收缩压反应性显著相关。结论miRNA基因多态性与血压钠钾反应性密切相关,提示miRNA基因可能参与血压盐敏感性及钾敏感性的形成。

Accumulation and exploration enlightenment of shallow normal-pressure shale gas in southeastern Sichuan Basin, SW China

Based on the drilling, logging, experimental and testing data of Well PD1, a shallow normal-pressure shale gas well in the Laochangping anticline in southeastern Sichuan Basin, the shallow shale gas reservoirs of the Ordovician Wufeng Formation to Silurian Longmaxi Formation (Wufeng-Longmaxi) were investigated in terms of geological characteristics, occurrence mechanism, and adsorption-desorption characteristics, to reveal the enrichment laws and high-yield mechanism of shallow normal-pressure shale gas in complex structure areas. First, the shallow shale gas reservoirs are similar to the medium-deep shale gas reservoirs in static indicators such as high-quality shale thickness, geochemistry, physical properties and mineral composition, but the former is geologically characterized by low formation pressure coefficient, low gas content, high proportion of adsorbed gas, low in-situ stress, and big difference between principal stresses. Second, shallow shales in the complex structure areas have the gas occurrence characteristics including low total gas content (1.1-4.8 m3/t), high adsorbed gas content (2.5-2.8 m3/t), low sensitive desorption pressure (1.7-2.5 MPa), and good self-sealing. Third, the adsorbed gas enrichment of shales is mainly controlled by organic matter abundance, formation temperature and formation pressure: the higher the organic matter abundance and formation pressure, the lower the formation temperature and the higher the adsorption capacity, which is more beneficial for the adsorbed gas occurrence. Fourth, the shallow normal-pressure shale gas corresponds to low sensitive desorption pressure. The adsorbed gas can be rapidly desorbed and recovered when the flowing pressure is reduced below the sensitive desorption pressure. Fifth, the exploration breakthrough of Well PD1 demonstrates that the shallow complex structure areas with adsorbed gas in dominance can form large-scale shale reservoirs, and confirms the good exploration potential of shallow normal-pressure shale gas in the margin of the Sichuan Basin.

Ginger oil-loaded transdermal adhesive patch treats post-traumatic stress disorder

Objective:To find a viable alternative to reduce the number of doses required for the patients with post-traumatic stress disorder(PTSD),and to improve efficacy and patient compliance.Methods: In this study,we used ginger oil,a phytochemical with potential therapeutic properties,to prepare ginger oil patches.High-performance liquid chromatography(HPLC)was used to quantify the main active component of ginger oil,6-gingerol.Transdermal absorption experiments were conducted to optimize the various pressure-sensitive adhesives and permeation enhancers,including their type and concentration.Subsequently,the ginger oil patches were optimized and subjected to content determination and property evaluations.A PTSD mouse model was established using the foot-shock method.The therapeutic effect of ginger oil patches on PTSD was assessed through pathological sections,behavioral tests,and the evaluation of biomarkers such as tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),brain-derived neurotrophic factor(BDNF),and melatonin(MT).Results: The results demonstrated that ginger oil patches exerted therapeutic effects against PTSD by inhibiting inflammatory responses and modulating MT and BDNF levels.Pharmacokinetic experiments revealed that ginger oil patches maintained a stable blood drug concentration for at least one day,addressing the rapid metabolism drawback of 6-gingerol and enhancing its therapeutic efficacy.Conclusions: Ginger oil can be prepared as a transdermal drug patch that meets these requirements,and the bioavailability of the prepared patch is better than that of oral administration.It can improve PTSD with good patient compliance and ease of administration.Therefore,it is a promising therapeutic formulation for the treatment of PTSD.

Exploration of cardiac rehabilitation nursing for elderly patients with myocardial infarction based on individualized cardiac rehabilitation

BACKGROUND Myocardial infarction is a high-risk condition prevalent among the elderly population,often leading to adverse clinical manifestations such as reduced cardiopulmonary function,anxiety,and depression post-surgery.Consequently,cardiac rehabilitation holds immense importance in mitigating these complications.AIM To evaluate the effect of individualized cardiac rehabilitation on blood pressure variability(BPV)and baroreflex sensitivity(BRS)in elderly patients with myocardial infarction.METHODS A cohort of 74 elderly patients diagnosed with myocardial infarction and admitted to our hospital between January 2021 and January 2022 were subjected to random selection.Subsequently,all patients were divided into two groups,namely the research group(n=37)and the control group(n=37),utilizing the number table method.The control group received conventional drug treatment and nursing guidance intervention,while the study group underwent individualized cardiac rehabilitation in addition to the interventions received by the control group.All patients were continuously intervened for 12 wk,and the BPV of these two groups in the 1st wk(T0),the 4th wk(T1)and the 12th wk(T2)were compared,BRS,changes in cardiopulmonary function measures,and adverse cardiovascular events.RESULTS Of 24 h diastolic BPV,24 h systolic BPV,carbon dioxide ventilation equivalent slope of the research group were lower than those of the control group at T1 and T2,BRS,peak heart rate and systolic blood pressure product,1 min heart rate recovery were higher than those of the control group,and the incidence of adverse events in the research group was lower than that of the control group,the difference was statistically significant(P<0.05).CONCLUSION In this study,we found that after individualized cardiac rehabilitation in elderly patients with myocardial infarction,BPV and BRS can be effectively improved,cardiac function is significantly enhanced,and a better prognosis is obtained.

Evaluation of Well Spacing for Primary Development of Fractured Horizontal Wells in Tight Sandstone Gas Reservoirs

Methods for horizontal well spacing calculation in tight gas reservoirs are still adversely affected by the complexity of related control factors,such as strong reservoir heterogeneity and seepage mechanisms.In this study,the stress sensitivity and threshold pressure gradient of various types of reservoirs are quantitatively evaluated through reservoir seepage experiments.On the basis of these experiments,a numerical simulation model(based on the special seepage mechanism)and an inverse dynamic reserve algorithm(with different equivalent drainage areas)were developed.The well spacing ranges of Classes I,II,and III wells in the Q gas field are determined to be 802–1,000,600–662,and 285–400 m,respectively,with their average ranges as 901,631,and 342.5 m,respectively.By considering both the pairs of parallel well groups and series well groups as examples,the reliability of the calculation results is verified.It is shown that the combination of the two models can reduce errors and provide accurate results.

Influence of Working Pressure on Ion Sensitive Probe Measurement in Microwave ECR Plasmas

In order to precisely measure the ion parameters in a microwave electron cyclotron resonance plasma using an ion sensitive probe,the dependences of the current-voltage（I-V）characteristics on the shielding height（h）and the potential difference between inner and outer electrodes（V_B）have been investigated at different working pressures of 0.03 Pa and 0.8 Pa.Results show that the I-V curves at higher pressure are more sensitive to the variation of h than those at lower pressure.The influence of V_B on ion temperature（T_i）measurement becomes more prominent when the pressure is increased from 0.03 Pa to 0.8 Pa.Under both pressures,the optimized h is obtained at the condition where the current reaches zero in the positive voltage region with a suitable V_B of-1.5 V because of effective shielding of the electron E×B drift.

Field-assisted tunneling enabled pressure-sensitive composites/sensors for smart concrete structures

Spiky spherical nickel powder with sharp nano-tips on its surface is a kind of excellent fillers for developing pressure-sensitive cement-based composites/sensors for traffic detection,structural health monitoring,and border and military security.The sharp nano-tips on the surface of spiky spherical nickel particles can induce field emission and tunneling effects,which leads to the ultrahigh pressure-sensitive responses of the cement-based composites.In this paper,we systematically introduce research on nanotip-induced ultrahigh pressure-sensitive cement-based composites/sensors,with attentions to their pressure-sensitive property and sensing mechanism,pressure-sensitive characteristic model,and smart structure system for traffic detection.

Test and Study of the Rock Pressure Sensitivity for KeLa-2 Gas Reservoir in the Tarim Basin

KeLa-2 gas reservoir is the largest uncompartimentalized gas field so far discovered in China, with a reserve of hundreds of billions of cubic meters of dry gas. It has such features as extremely long interval (550m), high pressure (74.5MPa) and pressure coefficient (2.022). Gas reservoirs with a pressure coefficient of over 2.0 are not commonly found. The abnormal high-pressure reservoirs are quite different in characteristic and performance during the process of depletion exploitation. Therefore, it is necessary to know the property of pressure sensitivity for this abnormal high-pressure reservoir. The aim of this paper is to test the reservoir pressure sensitivity and to analyze its effect on the deliverability of gas. Through some experiments, the permeability change with the confining pressure of rock samples from KeLa-2 abnormal high-pressure gas reservoir is measured. A power function is used to match the measured data, and to derive an empirical equation to describe the change of permeability through the change of the reservoir pressure or effective overburden pressure. Considering the permeability change during the development of reservoirs, a conventional deliverability equation is modified, and the deliverability curve for KeLa-2 gas reservoir is predicted. The research indicates that the extent of the pressure sensitivity of rock samples from KeLa-2 is higher than that from the Daqing oilfield. KeLa-2 reservoir rock has the feature of an undercompaction state. The pressure sensitivity of a reservoir may decrease the well deliverability. It is concluded that for KeLa-2 reservoir the predicted absolute open flow (AOF), when the pressure sensitivity is taken into account, is approximately 70% of the AOF when permeability is constant and does not change with pressure.

Predictive accuracy of the Braden Q Scale in risk assessment for paediatric pressure ulcer: A meta-analysis

Aims:Paediatric pressure ulcers are a serious problem to healthcare service.Thus,effective and early identification of the risk of developing pressure ulcer is essential.The Braden Q scale is a widely used tool in the risk assessment of paediatric pressure ulcer,but its predictive power is controversial.Hence,we performed a meta-analysis to evaluate the predictive power of the Braden Q scale for pressure ulcer in hospitalised children and offer recommendations for clinical decision.Methods:Studies that evaluated the predictive power of the Braden Q scale were searched through databases in English and Chinese,including Medline,Cochrane Library,Embase,CINAHL,SinoMed,CNKI,Wangfang and VIP.The studies were screened by two independent reviewers.QUADAS-2 was used to assess the risk of bias of eligible studies.Demographic data and predictive value indices were extracted.The pooled sensitivity,specificity and receiver operating characteristics(ROC)were calculated by MetaDiSc 1.4 using random-effects models.Results:Cochran Q=26.13(P=0.0036)indicated the existence of heterogeneity;the I2 for pooled DOR was 61.7%,suggesting significant heterogeneity among the included studies.The pooled sensitivity and specificity were 0.73(95%CI:0.67-0.78)and 0.61(95%CI:0.59-0.63),respectively,yielding a combined DOR of 3.47(95%CI:2-6.01).The area under the ROC curve was 0.7078±0.0421,and the overall diagnostic accuracy(Q*)was 0.6591±0.0337.Sensitivity analysis showed the results were robust.Conclusion:The Braden Q scale has moderate predictive validity with medium sensitivity and low specificity for pressure ulcers in hospitalised children.Further development and modification of this tool for use in paediatric population are warranted.

High-Porosity Foam-Based Iontronic Pressure Sensor with Superhigh Sensitivity of 9280 kPa^(-1)

Flexible pressure sensors with high sensitivity are desired in the fields of electronic skins,human-machine interfaces,and health monitoring.Employing ionic soft materials with microstructured architectures in the functional layer is an effective way that can enhance the amplitude of capacitance signal due to generated electron double layer and thus improve the sensitivity of capacitive-type pressure sensors.However,the requirement of specific apparatus and the complex fabrication process to build such microstructures lead to high cost and low productivity.Here,we report a simple strategy that uses open-cell polyurethane foams with high porosity as a continuous three-dimensional network skeleton to load with ionic liquid in a one-step soak process,serving as the ionic layer in iontronic pressure sensors.The high porosity(95.4%) of PU-IL composite foam shows a pretty low Young's modulus of 3.4 kPa and good compressibility.A superhigh maximum sensitivity of 9,280 kPa^(-1) in the pressure regime and a high pressure resolution of 0.125% are observed in this foam-based pressure sensor.The device also exhibits remarkable mechanical stability over 5,000 compression-release or bending-release cycles.Such high porosity of composite structure provides a simple,cost-effective and scalable way to fabricate super sensitive pressure sensor,which has prominent capability in applications of water wave detection,underwater vibration sensing,and mechanical fault monitoring.

Calculation of Surrounding Rock Pressure of Undercut Subway Station Based on Multi-Factor Affecting Pressure Arch Theory

The formation mechanism of surrounding rock pressure in large-section tunnels of underground excavation is still unclear. The traditional methods for calculating surrounding rock pressure have certain limitations. Based on the theory of pressure arch and parameter sensitivity analysis, the internal and external boundaries of the pressure arch are solved by numerical simulation. The loose pressure is obtained according to the distance from the inner boundary to the inner wall of the tunnel. The pressure arch deformation is analyzed based on the Winkler model. The surrounding rock pressure is calculated, and the surrounding rock pressure based on the pressure arch theory is calculated. The calculation method of surrounding rock pressure based on the pressure arch theory large section tunnel is proposed. The orthogonal experimental design method was used to select four representative factors: tunnel depth H, span B, internal friction angle φ and rock weight γ. The calculation results of each group of experiments were compiled and multivariate linear regression was used. The method is statistically analyzed, and finally, the calculation formula of the surrounding rock pressure of the large-section tunnel affected by multiple factors is obtained and applied to the calculation of the surrounding rock pressure of the metro station.

Numerical investigation of a coupled moving boundary model of radial flow in low-permeable stress-sensitive reservoir with threshold pressure gradient

The threshold pressure gradient and formation stress-sensitive effect as the two prominent physical phenomena in the development of a low-permeable reservoir are both considered here for building a new coupled moving boundary model of radial flow in porous medium. Moreover, the wellbore storage and skin effect are both incorporated into the inner boundary conditions in the model. It is known that the new coupled moving boundary model has strong nonlinearity. A coordinate transformation based fully implicit finite difference method is adopted to obtain its numerical solutions. The involved coordinate transformation can equivalently transform the dynamic flow region for the moving boundary model into a fixed region as a unit circle, which is very convenient for the model computation by the finite difference method on fixed spatial grids. By comparing the numerical solution obtained from other different numerical method in the existing literature, its validity can be verified. Eventually, the effects of permeability modulus, threshold pressure gradient, wellbore storage coefficient, and skin factor on the transient wellbore pressure, the derivative, and the formation pressure distribution are analyzed respectively.

Soil Pressure Mini-sensor Made of Monocrystalline Silicon and the Measurement of Its Sensitivity Coefficient

A calibration test was done in order to measure its sensitivity coefficient by an improved soil test device.The experimental result shows that the soil pressure min-sensor made of the monocrystalline silicon（SPMMS）is proved to be good linear,high precision and less that can fetch precise data in low pressure range even near by O point,which guarantees the reliability of the soil pressure test in geotechnical engineering.

A SIX-YEAR RETROSPECTIVE STUDY ON THE RELATIONSHIP OF SODIUM-LITHIUM COUNTERTRANSPORT WITH BLOOD PRESSURE AND SODIUM SENSITIVITY IN CHILDREN

Red-cell membrane sodium-lithium countertransport (Na+-Li+CT) and sodium sensitivity (SS) were measured in 300 children in Hanzhong.By comparison and retrospective study, the results showed:①In children with higher blood pressure(HBP) and positive rainily history (FH+),Na+-Li+ CT rate was signiricantly higher than that in controls (P<0. 01).②6-year retrospective review of blood pressure evolution, the blood pressure increased degree (ASBP) in children with higher Na+-Li+ CT rate was much greater than that in those with lower one (P<0.05), and at the same time,the percentiles of systolic blood pressure (PSBP) for children with higher countertransport mostly kept rising or kept higher levels during this period.③In children with SS, Na+-Li+ CT rate was increased than that in SR group (P<0. 01),and was correlated to the concentration of intra-erythrocytic Na+ (P= 0.004).These suggest that, as intermediate phenotype of essential hypertension, red-cell membrane sodium-lithium countertransport defect could participate in the regulation of blood pressure and pathogensis or hypertension development in children.

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing. Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years. Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teena-gers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8 ±5.2 mmHg, P< 0.01; 12.2% ±12.0% vs. 2.5% ±4.4%, P< 0.001, respectively). There was a similar trend for diastolic blood pressure (8.4 ±6.4 mmHg vs. 3.7 ±6.4 mmHg, P= 0.052; 13.2% ±10.6 % vs. 6.8% ±10.1%, P= 0.053, respectively). Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.

Fiber Bragg Grating Pressure Sensor Based on Corrugated Diaphragm

A kind of fiber Bragg grating pressure sensor based on corrugated diaphragm is proposed. The relationship between the central wavelength of reflective wave of FBG and pressure is given, and the expression of the pressure sensitivity coefficient is also given. Within the range from 0 MPa to 0.3 MPa, the experimental pressure sensitivity is 7.83 nm/MPa, which is 2 610 times than that of the bare fiber grating. The experimental results agree with the theoretical analysis. It is indicated that the expected pressure sensitivity of the sensor can be obtained by optimizing the size and mechanical parameters of the corrugated diaphragm.