Applying Neural Networks for Tire Pressure Monitoring Systems

A proof-of-concept indirect tire-pressure monitoring system is developed using artificial neural networks to identify the tire pressure of a vehicle tire.A quarter-car model was developed with MATLAB and Simulink to generate simulated accelerometer output data.Simulation data are used to train and evaluate a recurrent neural network with long short-term memory blocks(RNN-LSTM)and a convolutional neural network(CNN)developed in Python with Tensorflow.Bayesian Optimization via SigOpt was used to optimize training and model parameters.The predictive accuracy and training speed of the two models with various parameters are compared.Finally,future work and improvements are discussed.

Tire Pressure Monitoring System Using SoC and Low Power Design

This paper presents the tire pressure monitoring system (TPMS) by using the system on chip (SoC) mixed signals with the help of Bluetooth transmission and in advantage of low power consumption design. This is to monitor the variations in temperature and pressure of the vehicle’s tire, and the TPMS system is involved. It improves the driver’s safety by automatically detecting the tire pressure and temperature and then warning signal is sent to driver to take a measure, which prevents from accident. The proposed system of tire pressure monitoring system using SoC increases the speed of indication time to the driver by using mixed signals. The inflation of the tire can be avoided by preventing from high temperature and high pressure. Limitation of temperature and pressure in the previous system is also elongated i.e. temperature from 40℃ to 125℃ and pressure from 0 to 750 Kpa. Sensors, wireless communication (Bluetooth dongle) and SoC unit are used to design the low power TPMS. Quantitative results are taken and the analogy between temperature and pressure is also verified. The tested results proved by need of the practical system. Signal conditioning voltage and SoC unit is the trace for low power design TPMS. Finally, the performance of the system is tested and executed by using proteus software given as a real time application.

Influence of Unbalance on Classification Accuracy of Tyre Pressure Monitoring System Using Vibration Signals

Tyre Pressure Monitoring Systems(TPMS)are installed in automobiles to monitor the pressure of the tyres.Tyre pressure is an important parameter for the comfort of the travelers and the safety of the passengers.Many methods have been researched and reported for TPMS.Amongst them,vibration-based indirect TPMS using machine learning techniques are the recent ones.The literature reported the results for a perfectly balanced wheel.However,if there is a small unbalance,which is very common in automobile wheels,‘What will be the effect on the classification accuracy?’is the question on hand.This paper attempts to study the effect of unbalance of the wheel on the classification accuracy of an indirect TPMS system.The tyres filled with air are considered with different pressure values to represent puncture,normal,under pressure and overpressure conditions.The vibration signals of each condition were acquired and processed using machine learning techniques.The procedure is carried out with perfectly balanced wheels and known unbalanced wheels.The results are compared and presented.

RF energy harvesting system for wireless intraocular pressure monitoring

This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize the conversion efficiency of the rectifier,and the design principle of an implantable antenna is introduced from material selection and structure design.Results from testing demonstrate that the antenna gain is about-20 dBi and the rectifier's maximum total conversion efficiency which contains match efficiency and rectifying efficiency is 47.18%under the implementation of0.18μm standard CMOS process.The maximum power obtained from the proposed system is 8μW when the power density of electromagnetic wave is lower than the national standard 40μW/cm^2 at915 MHz,which is enough to power the intraocular pressure monitoring system.

New Method for Monitoring Tire Pressure of Cars Based on the Tire Radial Deformation

Monitoring tire pressure of cars and signaling abnormal conditions is an important means to prevent deadly accidents. Large achievements have been gained, especially in direct tire pressure monitoring system（TPMS）. But there has been rarely research on indirect TPMS in the world. In China, the research on indirect TPMS is almost lacking. The international research on the indirect monitoring tire pressure method is mainly based on measuring and comparing the rotating speed of wheels. But it is very difficult to measure wheel rotating speed accurately because of the influence of many random factors. In this paper, the authors propose a new method in which the tire pressure can be monitored indirectly. This method can be used for tire calibration, wheel speed frequency standardization, wheel speed frequency comparison, and abnormal tire pressure determination. The pulse frequencies from wheel speed sensors of ABS are used to indicate tire deformation. Because the frequency has a relationship with tire deformation, the tire deformation reflects the tire pressure. Small sample statistics is used in the new method to increase the accuracy, and the experimental samples using the principle of the new method have been made and tested. The result of vehicle tests on road demonstrates that the method is efficient and accurate to monitor tire pressure. The research has positive potential for developing products.

Mining pressure monitoring and analysis in fully mechanized backfilling coal mining face-A case study in Zhai Zhen Coal Mine

Fully mechanized solid backfill mining(FMSBM) technology adopts dense backfill body to support the roof. Based on the distinguishing characteristics and mine pressure control principle in this technology, the basic principles and methods for mining pressure monitoring were analyzed and established. And the characteristics of overburden strata movement were analyzed by monitoring the support resistance of hydraulic support, the dynamic subsidence of immediate roof, the stress of backfill body, the front abutment pressure, and the mass ratio of cut coal to backfilled materials. On-site strata behavior measurements of 7403 W solid backfilling working face in Zhai Zhen Coal Mine show that the backfill body can effectively support the overburden load, obviously control the overburden strata movement, and weaken the strata behaviors distinctly. Specific performances are as follows. The support resistance decreases obviously; the dynamic subsidence of immediate roof keeps consistent to the variation of backfill body stress, and tends to be stable after the face retreating to 120-150 m away from the cut. The peak value of front abutment pressure arises at 5-12 m before the operating face, and mass ratio is greater than the designed value of 1.15, which effectively ensures the control of strata movement. The research results are bases for intensively studying basic theories of solid backfill mining strata behaviors and its control, and provide theoretical guidance for engineering design in FMSBM.

Ambulatory blood-pressure monitoring, antihypertensive therapy and the risk of fall injuries in elderly hypertensive patients

Background Fall injuries are common among the elderly. The aim of this study was to investigate whether blood-pressure patterns, as measured by 24-h ambulatory blood pressure monitoring （ABPM）, or intensification of antihypertensive therapy following the 24-h ABPM, may be associated with fall injuries in hypertensive elderly patients. Methods In a retrospective study, community-based elderly patients （age ≥ 70 years） who were referred to 24-h ABPM were evaluated for fall injuries within one-year post-ABPM. We compared the clinical characteristics, 24-h ABPM patterns and the intensification of hypertensive therapy following 24-h ABPM, between patients with and without a fall injury. Results Overall 1032 hypertensive elderly patients were evaluated. Fifty-five （5.3%） had a fall injury episode in the year following ABPM. Patients with a fall injury were significantly older, and with higher rates of previous falls. Lower 24-h diastolic blood-pressure （67.3 ± 7.6 vs. 70.7 ± 8.8 mmHg; P 〈 0.005） and increased pulse-pressure （74.7 ± 14.3 vs. 68.3 ± 13.7 mmHg; P 〈 0.005）, were found in the patients with a fall injury, compared to those without a fall injury. After adjustment for age, gender, diabetes mellitus and previous falls, lower diastolic blood-pressure and increased pulse-pressure were independent predictors of fall injury. Intensification of antihypertensive treatment following the 24-h ABPM was not associated with an increased rate of fall injury. Conclusions Low diastolic blood-pressure and increased pulse-pressure in 24-h ABPM were associated with an increased risk of fall injury in elderly hypertensive patients. Intensification of antihypertensive treatment following 24-h ABPM was not associated with an increased risk of fall injury.

Ambulatory pulmonary artery pressure monitoring in advanced heart failure patients

Heart failure (HF) is an emerging epidemic associate with significant morbidity, mortality, and health care expenditure. Although there were major advances in pharmacologic and device based therapies for the management of HF, mortality of this condition remains high. Accurate monitoring of HF patients for exacerbations is very important to reduce recurrent hospitalizations and its associated complications. With the failure of clinical signs, tele-monitoring, and laboratory bio-markers to function as early markers of HF exacerbations, more sophisticated techniques were sought to accurately predict the circulatory status in HF patients in order to execute timely pharmacological intervention to reduce frequent hospitalizations. CardioMEMSTM (St. Jude Medical, Inc., Saint Paul, Minnesota) is an implantable, wireless pulmonary arterial pressure (PAP) monitoring system which transmits the patient’s continuous PAPs to the treating health care provider in the ambulatory setting. PAP-guided medical therapy modification has been shown to significantly reduce HF-related hospitalization and overall mortality. In advanced stages of HF, wireless access to hemodynamic information correlated with earlier left ventricular assist device implantation and shorter time to heart transplantation.

Clinical Study on Evaluation of Autonomic Nervous Dysfunction Based on Imaging Urodynamic Examination with Slow Filling and Synchronous Blood Pressure Monitoring in the Patients with Cervicothoracic Spinal Cord Injury

Objective: Explore the rule of autonomic nervous dysfunction in the patients with urination disorder after high level spinal cord injury, and seek a safe, objective and accurate method to evaluate autonomic nervous function. Patients and Method: 48 patients with dysuria after cervicothoracic SCI were selected. Before, during and after imaging urodynamic examination with slow filling in supine position, blood pressure and ECG were monitored simultaneously. The symptoms of sweating, shivering, headache, flushing and chills were observed and recorded. The study of the relationship among the changes of blood pressure, heart rate and urodynamic indexes and the above symptoms was analyzed. Results: They were divided into three groups: group A (no obvious abnormality), group B (hyperactivity) and group C (hypoactivity) according to their BP, HR and existing the symptoms or not. Conclusion: The incidence of autonomic dysfunction in the high level SCI patients with dysuria was very high (79.17%), most of them were hyperactivity, and a few were low function. The changes of SBP and DBP in the hypoactivity group all appeared an increasing and then declining trend, while the change of HR in the low function one was lower than normal and decreased continuously. The main inducements of AD are neurogenic detrusor overactivity, detrusor sphincter dyssynergia, elevated abdominal pressure and abnormal bladder sensitivity. The asymptomatic patients had a higher occurrence rate (43.75%). Only by imaging urodynamic examination with slow filling and synchronous blood pressure monitoring, can autonomic nervous function of the patients be evaluated safely, objectively, early and accurately.

Individualized Isonatremic and Hyponatremic Dialysate Improves Blood Pressure in Patients with Intradialytic Hypertension: A Prospective Cross-Over Study with 24-h Ambulatory Blood Pressure Monitoring

Background. Intradialytic hypertension, a paradoxical rise in systolic blood pressure from pre- to postdialysis, is a poorly understood and difficult-to-treat phenomenon. We examined the effects of individually adjusted isonatremic and hyponatremic dialysate on intradialytic and interdialytic blood pressure in patients with intradialytic hypertension. Methods. We enrolled 11 patients with intradialytic hypertension in a prospective randomized cross-over study, with 4 treatment periods of different dialysate sodium concentrations. Period 1 (run-in) and 3 (wash-out) were standardized at 140 mEq/L;period 2 and 4 with iso- or hyponatremic sodium dialysate. Blood pressure was recorded each dialysis session, and 24-hour ambulatory blood pressure monitoring was performed at the end of each treatment period. Results. Isonatremic and hyponatremic dialysate were associated with significantly lower pre- and post-dialysis blood pressure as compared to baseline 140 mEq/L dialysate (predialysis 148.3 ± 24.7/67.7 ± 12.0 and 144.4 ± 16.5/68.8 ± 13.3 vs. 158.0 ± 18.3/75.6 ± 11.4 mmHg, resp p = 0.04 and 0.007 for systolic and p = 0.004 and 0.04 for diastolic blood pressure;postdialysis 154.2 ± 25.5/76.6 ± 14.1 and 142.5 ± 20.7/73.0 ± 12.9 vs. 159.1 ± 21.6/80.3 ± 12.1 mmHg, resp NS and p = 0.01 for systolic and NS and p = 0.04 for diastolic blood pressure). Postdialysis and 24 h systolic blood pressure tended to be lower with hyponatremic compared to isonatremic dialysate. Conclusion. Individually tailoring dialysate sodium concentration, based on the sodium set-point of each patient, resulted in a lower pre- and post-dialysis blood pressure in patients with intradialytic hypertension. 24 h blood pressure values tended to be lower as well with hyponatremic dialysate.

Effects of Continuous Non-Invasive Blood Pressure Monitoring on Intraoperative Hemodynamics and Postoperative Myocardial Injury in Craniotomy:Comparison Between Groups Based on Self-Control and Propensity Score Matching

Objective:To explore the effect of continuous non-invasive blood pressure monitoring on intraoperative hemodynamics and postoperative myocardial injury in craniotomy.Methods:120 cases of elective craniotomy were divided into the self-control group(continuous non-invasive blood pressure monitoring and intermittent cuff non-invasive blood pressure monitoring,CNAP group)and propensity score matching group(only intermittent cuff non-invasive blood pressure measurement in previous craniotomy,PSM group);Goal-directed hemodynamic management in CNAP group included heart rate(HR),blood pressure(BP),stroke volume(SV),stroke variability(SVV),and systemic vascular resistance index(SVRI).The main index is to compare the troponin level within 72 hours after operation between the CNAP group and the PSM group;The secondary indicators are the comparison of the hemodynamic conditions between the CNAP group and the PSM at 10 specific time points.Results:The incidence of postoperative myocardial injury in the CNAP group was significantly lower than that in the PSM group(12%vs.30%,P=0.01);in the CNAP group hypotensive episodes(6 vs.3,P=0.01),positive balance of fluid therapy(700 vs.500 mL,P<0.001),more use of vasoactive drugs(29 vs.18,P=0.04),more stable hemodynamics medical status(P=0.03)were recorded.Conclusion:The hemodynamic management strategy based on continuous non-invasive blood pressure monitoring can reduce the incidence of myocardial injury after elective craniotomy and maintain a more stable hemodynamic state.

Epidural Blood Patches Performed with Miethke Sensor Reservoir for Continuous Intracranial Pressure Monitoring

An epidural blood patch (EBP) is a procedure performed by injecting autologous blood into a patient’s epidural space, usually at the site of a suspected CSF leak. It is typically performed in patients with characteristic postural headaches due to low intracranial pressure. We report a case of a young female with an implanted Miethke Sensor Reservoir, which was used for continuous intracranial pressure (ICP) monitoring during a two-level epidural blood patch. ICP increased only with thoracic injection, suggesting thoracic EBP may have greater efficacy than lumbar EBP in treating SIH and PDPH when the site of CSF leak is unknown.

Classifying Machine Learning Features Extracted from Vibration Signal with Logistic Model Tree to Monitor Automobile Tyre Pressure

Tyre pressure monitoring system(TPMS)is compulsory in most countries like the United States and European Union.The existing systems depend on pressure sensors strapped on the tyre or on wheel speed sensor data.A difference in wheel speed would trigger an alarm based on the algorithm implemented.In this paper,machine learning approach is proposed as a new method to monitor tyre pressure by extracting the vertical vibrations from a wheel hub of a moving vehicle using an accelerometer.The obtained signals will be used to compute through statistical features and histogram features for the feature extraction process.The LMT(Logistic Model Tree)was used as the classifier and attained a classification accuracy of 92.5%with 10-fold cross validation for statistical features and 90.5% with 10-fold cross validation for histogram features.The proposed model can be used for monitoring the automobile tyre pressure successfully.

Influence of dynamic pressure on deep underground soft rock roadway support and its application

Due to high ground stress and mining disturbance, the deformation and failure of deep soft rock roadway is serious, and invalidation of the anchor net-anchor cable supporting structure occurs. The failure characteristics of roadways revealed with the help of the ground pressure monitoring. Theoretical analysis was adopted to analyze the influence of mining disturbance on stress distribution in surrounding rock,and the change of stress was also calculated. Considering the change of stress in surrounding rock of bottom extraction roadway, the displacement, plastic zone and distribution law of principal stress difference under different support schemes were studied by means of FLAC3D. The supporting scheme of U-shaped steel was proposed for bottom extraction roadway that underwent mining disturbance. We carried out a similarity model test to verify the effect of support in dynamic pressure. Monitoring results demonstrated the change rules of deformation and stress of surrounding rock in different supporting schemes. The supporting scheme of U-shaped steel had an effective control on deformation of surrounding rock. The scheme was successfully applied in underground engineering practice, and achieved good technical and economic benefits.

Experiment and analysis of the formation,expansion and dissipation of gasbag in fine sediments based on pore water pressure survey

Deep-seated gas in seabed sediments migrates upwards from effect of external factors,which easily accumulates to form gasbags at interface of shallow coarse-fine sediments.Real-time monitoring of this process is important to predict disaster.However,there is still a lack of effective monitoring methods,so we attempt to apply multi-points pore water pressure monitoring technology when simulating forming and dissipation of gasbags in sediments through laboratory experiment.This study focuses on discussion of sensitivity of pore water pressure monitoring data,as well as typical changing characteristics and mechanisms of excess pore water pressure corresponding to crack generation,gasbag formation and gas release.It was found that the value of excess pore water pressure in sediments is negatively correlated with vertical distance between sensors and gas source,and the evolution of gasbag forming and dissipation has a good corresponding relationship with the change of excess pore water pressure.Gasbag formation process is divided into three stages:transverse crack development,longitudinal cavity expansion,and oblique crack development.Formation of gasbag begins with the transverse crack at the interface of coarse-fine sediments while excess pore water pressure attenuates rapidly and then drops,pressure remains almost unchanged when cavity expanses longitudinally,oblique crack appeared in final stage of gasbag evolution while excess pore water pressure accumulated and dissipated again.The variation curve of excess pore water pressure in gas release stage has saw-tooth fluctuation characteristics,and the value and time of pressure accumulation are also fluctuating,indicating the uncertainty and non-uniqueness of gas migration channels in sediments.

A new approach for detecting sudden hypotension in hemodialysis by using dual-channel optical system

Dialysis hypotension is one of the most prevalence symptoms of dialysis and occurs in 40%of treatment sessions.Detection and prediction of hypotension is important for the well-being of the patient and for optimizing treatment.The aim of this study was to construct optical system to monitor blood pressure(BP)continuously and without cuff in hemodialysis based on pulse transit time(PTT)method.To measure the BP changes,dual channel optical system were developed.In this study,individuals were classified into two groups of normal and hemodialysis.In both groups,BP and consequently PTT were earned three times in different positions.After the initial calibration,the regression equation was drawn for each subject.In normal group,each subject was placed in the supine position and BP was measured both by designed system and sphyg-momanometer cuff.During BP measurements,in addition to BP,blood pressure decline was also monitored by optical system.For hemodialysis group,the same measurement setup was adopted.In both groups,the error between cuff method and PTT was calculated.Correlation coefficients for BPcuf vs BP pTT were calculated and Bland-Altman plot was performed for the normal and hemodialysis groups.In this study 16 subjects participated.The results for normal group showed that maximum difference between cuff method and the present method was 14 mmHg and for.dialysis group was 16 mmHg.Bland-A ltman plot in normal group revealed limits of agreement from-13.98 to 13.18 mmHg.Considering hemodialysis group,limits of agreement were from-15.94 to 13.88 mmHg.The correlation coefficient was 0.74 for normal group and was 0.72 for hemodialysis group.The proposed system can monitor BP continuously and diagnose sudden hypotension.So it can be recommended as a useful method to indicate hypotension and can be used for dialysis unit.

The relation between prognosis and nocturnal blood pressure variation in hypertensive patients with lacunar infarct

Objective We conducted a study using MRI and ambulatory blood pressure monitoring(ABPM) to determine whether an in-apporpriately low nocturnal blood pressure, or an excess fall in nocturnal blood pressure, might be responsible for lacunar infarct. Method ABPM and Casul blood pressure(CBP) were examined in 35 hypertentives with lacunar infarct(LI)and 33 hypertentives without lacunar infarct as control group. Results There is no significant difference of CBP between two groups. But the mean nighttime systolic blood pressure (nSBP) and diastolic blood pressure (nDBP) in patients with lacunar infarct were significantly smaller than in patients without lacunar infarct. The ratio of nSBP/dSBP and nDBP/dDBP in SI were smaller than in control group respectively. Conclusions The results indicate that an inap-propriately low nocturnal blood pressure, or an excessive fall in nocturnal blood pressure, is associated with lacunar infarct. It is necessary not only to control high blood pressure but also to pay attention to circadian changes of blood pressure during the course of anti-hypertensive treatment.

The Relationship between Abnormal Circadian Blood Pressure Rhythm and Risk of Readmission in Patients with Heart Failure with Preserved Ejection Fraction

Objective:Abnormal circadian blood pressure rhythm has been revealed to be associated with hypertensive target organ damage and cardiovascular events,but its association with readmission risk in patients with heart failure with preserved ejection fraction(HFpEF)remains unknown.We conducted a retrospective study to explore the relationship between circadian blood pressure rhythm and readmission risk in HFpEF patients.Methods:We retrospectively collected baseline and follow-up data on HFpEF patients who underwent ambulatory blood pressure monitoring(ABPM)from May 2015 to October 2019.Patient circadian blood pressure rhythms defi ned by ABPM were grouped as dipper,nondipper,or riser patterns.Univariate and multivariate linear regression analyses were performed to assess the association between circadian blood pressure rhythm and readmission risk.Results:A total of 122 patients were enrolled in this study.The mean age and ejection fraction were 69.87 years and 61.44%,respectively,with mean the N-terminal pro-B-type natriuretic peptide(NT-proBNP)level being 1048.15 pg/mL.There were signifi cant differences in the 24-hour systolic blood pressure(SBP),sleep SBP,and sleep diastolic blood pressure(DBP)among the three groups,where the 24-hour SBP,sleep SBP,and sleep DBP in the riser pattern group were markedly higher than in the dipper pattern group.Notably,serum NT-proBNP levels,the proportion of patients readmitted for heart failure and the mean number of admissions differed markedly among three groups.Instructively,multivariate linear regression analysis showed that the riser pattern was a signifi cant and independent risk factor for increased serum NT-proBNP level(β=929.16,95%confi dence interval 178.79–1679.53,P=0.016).In multivariate logistic regression analysis,the riser pattern was demonstrated to be a signifi cant risk factor for readmission(odds ratio 11.23,95%confi dence interval 2.01–62.67,P=0.006)in HFpEF patients.Conclusion:The riser blood pressure pattern is a potential risk factor for elevated serum NT-proBNP level and readmission in HFpEF patients.

Predictive Value of Blood Pressure,Heart Rate,and Blood Pressure/Heart Rate Ratio in a Chinese Subpopulation with Vasovagal Syncope

Objective:The head-up tilt test(HUTT)is widely used but is time-consuming and not cost-effective to evaluate patients with vasovagal syncope(VVS).The present study aims to verify the hypothesis that ambulatory blood pressure(BP)monitoring(ABPM)and the simplistic tilt test may be potential alternatives to the HUTT.Methods:The study consecutively enrolled 360 patients who underwent the HUTT to evaluate VVS.BP),heart rate(HR),and BP/HR ratios derived from ABPM and the simplistic tilt test were evaluated to predict the presence,pattern,and stage of syncope during the HUTT.Results:Mixed response was the commonest pattern,and syncope occurred frequently with infusion of isoproterenol at a rate of 3μg/min.During the simplistic tilt test,the cardioinhibitory group had higher tilted BP/HR ratios than the vasodepressor group,while the vasodepressor group had a faster tilted HR and a larger HR difference than the cardioinhibitory group.The higher the BP/HR ratio in the tilted position,the higher the isoproterenol dosage needed to induce a positive response.During ABPM,BP/HR ratios were signifi cantly higher in the cardioinhibitory group than in the vasodepressor group.The higher the ABPM-derived BP,the higher the dosage of isoproterenol needed to induce syncope.There were signifi cant correlations in BP/HR ratios between ABPM and the supine position in the vasodepressor group,while signifi cant correlation was found only for the diastolic BP/HR ratio between ABPM and the tilted position in the cardioinhibitory group.The mixed pattern shared correlative features of the other two patterns.Conclusion:ABPM and the simplistic tilt test might be used as promising alternatives to the HUTT in VVS evaluation in clinical settings.

THE CIRCADIAN ALTERATIONS OF BLOOD PRESSURE IN PATIENTS WITH SECONDARY HYPERTENSION

Objective To study the pattern of circadian blood pressure changes in patients with se-condary hypertension. Methods The 24h ambulatory blood pressure monitoring was performed in 80 patients with secondary hypertension (SH) including primary aldosteronism in 44, pheochromocytoma in 11, renovas-cular hypertension in 10, renoparenchymal hypertension in 15 and compared with 80 patients with essential hy-pertension (EH) matched by age and sex. Results The diurnal rhythm in patients with SH was different from that of patients with EU. The diurnal curves in SU and EU was overlapped in daytime and separated from each other at nighttime. The nocturnal blood pressure fall was less and average blood pressure at nighttime was higher in patients with SH than those in patients with Eli (P <0. 01). The nighttime blood pressure loading and non-dipper phenomenon were much more frequently seen in patients with SH than those in patients with Eli (P <0. 01). The nighttime blood pressure/daytime blood pressure ratio was significantly higher in patients with SH than that in patients with Eli (P <0. 01). Conclusion The non-invasive 24h ambulatory blood pressure monitoring may be a useful method in screening for