Adsorption mechanism of different coal ranks under variable temperature and pressure conditions

Variable temperature and pressure adsorption tests were conducted on four coal samples with different coal ranks, under simulated temperatures and pressures corresponding to coal reservoirs at different depths. The regularity of the variation in the amounts of adsorption by coals under variable temperature and pressure and 30 ℃ isothermal conditions are compared and the adsorption characteristics of coal under the composite effect of temperature and pressure were obtained. The adsorption test and data processing method of coal under variable temperature and pressure are presented and the effect of the mechanism of temperature and pressure on the adsorption capacity of coal has been studied. The research results are of significant importance in the investigation of coalbed methane storage mechanism and for the prediction of the amounts of coalbed methane at various depths.

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.

Significance of blood pressure variability in patients with sepsis

BACKGROUND: This study was undertaken to observe the characteristics of blood pressure variability(BPV) and sepsis and to investigate changes in blood pressure and its value on the severity of illness in patients with sepsis.METHODS: Blood parameters, APACHE II score, and 24-hour ambulatory BP were analyzed in 89 patients with sepsis.RESULTS: In patients with APACHE II score>19, the values of systolic blood pressure(SBPV), diasystolic blood pressure(DBPV), non-dipper percentage, cortisol(COR), lactate(LAC), platelet count(PLT) and glucose(GLU) were significantly higher than in those with APACHE II score ≤19(P<0.05), whereas the values of procalcitonin(PCT), white blood cell(WBC), creatinine(Cr), PaO2, C-reactive protein(CRP), adrenocorticotropic hormone(ACTH) and tumor necrosis factor α(TNF-α) were not statistically significant(P>0.05). Correlation analysis showed that APACHE II scores correlated significantly with SBPV and DBPV(P<0.01, r=0.732 and P<0.01, r=0.762). SBPV and DBPV were correlated with COR(P=0.018 and r=0.318; P=0.008 and r=0.353 respectively). However, SBPV and DBPV were not correlated with TNF-α, IL-10, and PCT(P>0.05). Logistic regression analysis of SBPV, DBPV, APACHE II score, and LAC was used to predict prognosis in terms of survival and non-survival rates. Receiver operating characteristics curve(ROC) showed that DBPV was a better predictor of survival rate with an AUC value of 0.890. However, AUC of SBPV, APACHE II score, and LAC was 0.746, 0.831 and 0.915, respectively.CONCLUSIONS: The values of SBPV, DBPV and non-dipper percentage are higher in patients with sepsis. DBPV and SBPV can be used to predict the survival rate of patients with sepsis.

Correlation of Inferior Vena Cava Respiratory Variability Index with Central Venous Pressure and Hemodynamic Parameters in Ventilated Pigs with Septic Shock

Septic shock is a common critical condition, for which effective early fluid resuscitation is the therapeutic focus. According to the 2008 international guidelines for management of severe sepsis and septic shock, resuscitation should achieve a central venous pressure （CVP） of 8-12 mmHg within the first 6 h. However, it is still uncertain about the sensitivity and specificity of CVP in reflecting the cardiac preload. Ultrasonography is a simple, rapid, non-invasive, and repeatable method for the measurement of sensitivity and specificity of CVP and has thus gradually attracted the increasing attention of physicians. It was reported that ultrasonography can show the inferior vena cava diameter, respiratory variability index, and blood volume in patients with sepsis or heart failure.

Psychological stress and long-term blood pressure variability of military young males:The cardiorespiratory fitness and hospitalization events in armed forces study

BACKGROUND Acute stress might increase short-term heart rate variability and blood pressure variability(BPV);however,chronic stress would not alter short-term BPV in animal models.AIM To examine the association of psychological stress with long-term BPV in young male humans.METHODS We prospectively examined the association of chronic psychological stress with long-term BPV in 1112 healthy military males,averaged 32.2 years from the cardiorespiratory fitness and hospitalization events in armed forces study in Taiwan.Psychological stress was quantitatively evaluated with the Brief Symptom Rating Scale(BSRS-5),from the least symptom of 0 to the most severe of 20,and the five components of anxiety,insomnia,depression,interpersonal sensitivity,and hostility(the severity score in each component from 0 to 4).Longterm BPV was assessed by standard deviation(SD)for systolic and diastolic blood pressure(SBP and DBP),and average real variability(ARV),defined as the average absolute difference between successive measurements of SBP or DBP,across four visits in the study period from 2012 to 2018(2012-14,2014-15,2015-16,and 2016-18).RESULTS The results of multivariable linear regressions showed that there were no correlations of the BSRS-5 score with SDSBP,SDDBP,ARVSBP,and ARVDBP after adjusting for all the covariates[β(SE):-0.022(0.024),-0.023(0.026),-0.001(0.018),and 0.001(0.020),respectively;P>0.05 for all].In addition,there were also no correlations between each component of the BSRS score and the long-term BPV indexes.CONCLUSION Our findings suggest that chronic psychological stress might not be associated with long-term BPV in military young male humans.

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.

Cardiovascular age of aviation personnel: based on the principal component analysis of heart rate and blood pressure variability

Objective: To introduce a method to calculate cardiovascular age, a new, accurate and much simpler index for assessing cardiovascular autonomic regulatory function, based on statistical analysis of heart rate and blood pressure variability (HRV and BPV) and baroreflex sensitivity (BRS) data. Methods: Firstly, HRV and BPV of 89 healthy aviation personnel were analyzed by the conventional autoregressive (AR) spectral analysis and their spontaneous BRS was obtained by the sequence method. Secondly, principal component analysis was conducted over original and derived indices of HRV, BPV and BRS data and the relevant principal components, PCi orig and PCi deri (i=1, 2, 3,...) were obtained. Finally, the equation for calculating cardiovascular age was obtained by multiple regression with the chronological age being assigned as the dependent variable and the principal components significantly related to age as the regressors. Results: The first four principal components of original indices accounted for over 90% of total variance of the indices, so did the first three principal components of derived indices. So, these seven principal components could reflect the information of cardiovascular autonomic regulation which was embodied in the 17 indices of HRV, BPV and BRS exactly with a minimal loss of information. Of the seven principal components, PC2 orig , PC4 orig and PC2 deri were negatively correlated with the chronological age ( P <0 05), whereas the PC3 orig was positively correlated with the chronological age ( P <0 01). The cardiovascular age thus calculated from the regression equation was significantly correlated with the chronological age among the 89 aviation personnel ( r =0.73, P <0 01). Conclusion: The cardiovascular age calculated based on a multi variate analysis of HRV, BPV and BRS could be regarded as a comprehensive indicator reflecting the age dependency of autonomic regulation of cardiovascular system in healthy aviation personnel.

Metabolic biomarkers and long-term blood pressure variability in military young male adults

BACKGROUND Metabolic syndrome is a cluster of cardiovascular risk factors, including central obesity, high blood pressure, elevated plasma glucose, reduced high-density lipoprotein and elevated triglyceride levels.AIM To investigate the relationship between metabolic biomarkers and long-term blood pressure variability(BPV) in young males.METHODS A cohort of 1112 healthy military males aged 18-40 years from the cardiorespiratory fitness and hospitalization events in armed forces study in eastern Taiwan was prospectively included. The following metabolic biomarkers were used: Waist circumference, serum uric acid(SUA), triglycerides, high density lipoprotein, triglycerides, and fasting glycose. BPV was assessed by average real variability(ARV) and standard deviation(SD) across 4 clinic visits during the study period(2012-14, 2014-15, 2015-16, and 2016-18). Multivariable linear regression analysis was used to determine the association after adjusting for age, body mass index, systolic and diastolic blood pressure(SBP and DBP),lipid profiles, physical activity, alcohol intake and tobacco smoking status.RESULTS In the unadjusted model, waist circumference was significantly and positively correlated with ARVDBP and SDDBP [β(standard errors) = 0.16(0.049) and 0.22(0.065), respectively], as was SUA [β = 0.022(0.009) and 0.038(0.012),respectively]. High-density lipoprotein was negatively correlated with ARVSBP [β=-0.13(0.063)]. There were no associations with the other metabolic biomarkers.In contrast, only SUA was significantly correlated with SDSBP and SDDBP [β = 0.019(0.011) and 0.027(0.010), respectively] in the adjusted model.CONCLUSION Our findings showed that of traditional metabolic biomarkers, SUA had the strongest positive correlation with long-term systolic and diastolic BPV in young male adults, and the clinical relevance needs further investigation.

Day-to-day blood pressure variability predicts poor outcomes following percutaneous coronary intervention:A retrospective study

BACKGROUND For patients with cardiovascular disease,blood pressure variability(BPV),distinct from hypertension,is an important determinant of adverse cardiac events.Whether pre-operative BPV adversely affects outcomes after percutaneous coronary intervention(PCI)is to this point unclear.AIM To investigate the relationship between blood pressure variability and outcomes for patients post-PCI.METHODS Patients undergoing PCI in a single state in 2017 were studied(n=647).Systolic and diastolic BPV,defined as both the largest change and standard deviation for the 3-60 mo prior to PCI was calculated and patients with more than ten blood pressure measurements in that time were included for analysis(n=471).Adverse outcomes were identified up to a year following the procedure,including major adverse cardiac events(MACE),myocardial infarction,cerebrovascular accident,death,and all-cause hospitalization.RESULTS Visit-to-visit systolic BPV,as measured by both standard deviation and largest change,was higher in patients who had myocardial infarction,were readmitted,or died within one year following PCI.Systolic BPV,as measured by largest change or standard deviation,was higher in patients who had MACE,or readmissions(P<0.05).Diastolic BPV,as measured by largest change,was higher in patients with MACE and readmissions(P<0.05).CONCLUSION As BPV is easily measured and captured in the electronic medical record,these findings describe a novel method of identifying at-risk patients who undergo PCI.Aggressive risk modification for patients with elevated BPV and known coronary artery disease is indicated.

Spectral Analysis of Blood Pressure Variability as a Quantitative Indicator of Driving Fatigue

The quantitative detector of driver fatigue presents appropriate warnings and helps to prevent traffic accidents.The aim of this study was to quantifiably evaluate driver mental fatigue using the power spectral analysis of the blood pressure variability (BPV) and subjective evaluation. In this experiment twenty healthy male subjects were required to perform a driving simulator task for 3-hours. The physiological variables for evaluating driver mental fatigue were spectral values of blood pressure variability (BPV)including very low frequency (VLF), low frequency (LF),high frequency (HF). As a result, LF, HF and LF/HF showed high correlations with driver mental fatigue but not found in VLF. The findings represent a possible utility of BPV spectral analysis in quantitatively evaluating driver mental fatigue.

Study on blood pressure rhythm in hypertensive patients with Yin deficiency syndrome and a random forest model for predicting hypertension with Yin deficiency syndrome

OBJECTIVE: To investigate blood pressure rhythm(BPR)in Yin deficiency syndrome of hypertension(YDSH)patients and develop a random forest model for predicting YDSH.METHODS: Our study was consistent with technical processes and specification for developing guidelines of Evidence-based Chinese medicine clinical practice(T/CACM 1032-2017). We enrolled 234 patients who had been diagnosed with primary hypertension without antihypertensive medications prior to the enrollment. All participants were divided into Yin deficiency group(YX, n = 74) and non-Yin deficiency group(NYX, n = 160).Participants were professionally grouped by three experienced chief Traditional Chinese Medicine(TCM)physicians according to four examinations(i.e.,inspection, listening and smelling, inquiry and palpation).We collected data on 24 h ambulatory blood pressure monitoring(ABPM) and YDSH rating scale. We divided 24 h of a day into 12 two-hour periods [Chen-Shi(7:00-9:00), Si-Shi(9:00-11:00), Wu-Shi(11:00-13:00), Wei-Shi(13:00-15:00), Shen-Shi(15:00-17:00), You-Shi(17:00-19:00), Xu-Shi(19:00-21:00), Hai-Shi(21:00-23:00), ZiShi(23:00-1:00), Chou-Shi(1:00-3:00), Yin-Shi(3:00-5:00), Mao-Shi(5:00-7:00)] according to the theory of “midnight-midday ebb flow”. We used random forest to build the diagnostic model of YDSH, with whether it was Yin deficiency syndrome as the outcome. RESULTS: Compared with NYX group, YX group had more female participants with older age, lower waist circumference, body mass index(BMI), diastolic blood pressure(DBP), and smoking and drinking rate(all P < 0.05). The YDSH rating scores of YX group [28.5(21.0-36.0)] were significantly higher than NYX group [13.0(8.0-22.0)](P < 0.001), and the typical symptoms of YX group included vexing heat in the chest, palms and soles, dizziness, dry eyes, string-like and fine pulse, soreness and weakness of lumbus and knees, palpitations, reddened cheeks, and tinnitus(all P < 0.05). The ratio of non-dipper hypertension in YX group was higher than in NYX group(56.9% vs 44.4%, P = 0.004). Compared with NYX group, 24 h DBP standard deviation(SD), nighttime DBP SD, Si-Shi DBP, Si-Shi mean arterial pressure(MAP), Hi-Shi systolic blood pressure(SBP), Hi-Shi DBP, Hi-Shi MAP, Zi-Shi SBP, Zi-Shi DBP, Zi-Shi MAP, ChouShi SBP SD, Chou-Shi DBP SD, Chou-Shi SBP coefficient of variation(CV) were lower in YX group(all P < 0.05). Binary Logistic Regression analysis showed that the diagnosis of YDSH was positively correlated with age, heart rate, YDSH rating scores, and four TCM symptoms including vexing heat in the chest, palms and soles, string-like and fine pulse, soreness and weakness of lumbus and knees, and reddened cheeks(all P < 0.05), but was negatively correlated with smoking(P﹥0.05). In addition, the diagnosis of YDSH was positively correlated with daytime SBP SD, nighttime SBP SD, nighttime SBP CV, and Hi-Shi SBP CV, but was negatively correlated with 24 h SBP CV, daytime DBP SD, nighttime DBP SD, and Hi-Shi DBP(all P < 0.05). Hi-Shi SBP CV had independent and positive correlation with the diagnosis of YDSH after adjusting the variables of age, gender, course of hypertension, BMI, waist circumference, SBP, DBP, heart rate, smoking and drinking(P = 0.029). Diagnostic model of YDSH was established and verified based on the random forest. The results showed that the calculation accuracy, specificity and sensitivity were 77.3%, 77.8% and 76.9%, respectively. CONCLUSION: The BPR was significantly attenuated in YDSH patients, including lower 24 h DBP SD and nighttime DBP SD, and Hi-Shi SBP CV is independently correlated with the diagnosis of YDSH. The prediction accuracy of diagnosis model of YDSH based on the random forest was good, which could be valuable for clinicians to differentiate YDSH and non-Yin deficiency patients for more effective hypertensive treatment of TCM.

Local dynamic balance theory and technology of flow field in multilayer gob area

Flow field in multilayer gob area, which formed in small hiden-depth, multi-coal layer groups, close distance, hard coal layer, and hard roof, possesses characteristics such as complex, changeable and unstable. Dynamic balance theory of local flow field in multilayer gob area was built based on the realistic requirement that the serious threat on current mining coal layer by large-scale spontaneous combustion fire on close spontaneous combustion coal layer group of Datong Coal mining area at the ＇di-hard＇ conditions was caused by small coal pit mining. The kernel was in dynamic balance between flow field pressures of working face and local flow field in multilayer gob area was kept by transformation. Corresponding technology and set of devices were developed.

Effects of Chinese herbal medicine Yiqi Huaju Formula on hypertensive patients with metabolic syndrome:a randomized,placebo-controlled trial

BACKGROUND： Patients with hypertension coupled with metabolic syndrome （MetS） are among the high risk population in cardiovascular and cerebrovascular diseases. To reduce the prevalence of cardiovascular and cerebrovascular diseases, it is essential to appropriately control b^ood pressure together with other cardiovascular risk factors. OBJECTIVE： The current study was designed to investigate the therapeutic effects on blood pressure, blood pressure variability and other cardiovascular risk factors by giving Yiqi Huaju Formula, a compound traditional Chinese herbal medicine, in addition to routine treatment to hypertensive patients coupled with MetS. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS： A total of 43 patients with hypertension coupled with MetS were recruited into this study. The enrolled patients were randomly divided into the Chinese herbal formula group （anti-hypertensive drugs plus Yiqi Huaju Formula, CHF） and the control group （anti-hypertensive drugs plus placebo）. The CHF group enrolled 22 patients while the control group received 21 cases. Treatments were given for 12 weeks in both groups. MAIN OUTCOME MEASURES： Parameters examined include 24-hour ambulatory blood pressure monitoring, body mass index, waist circumference, waist-to-hip ratio, homeostatic model assessment for insulin resistance （HOMA-IR）, fasting glycosylated hemoglobin （HbAlc）, fasting plasma glucose, 2-hour postprandial plasma glucose （PPG）, fasting plasma insulin, serum lipid, etc. RESULTS： Compared with the control group, the CHF group had significant improvement （P〈0.01） in anthropometric parameters, FPG, HOMA-IR, blood pressure amplitude, blood pressure variability and blood pressure load. CONCLUSION： This study showed that integrated traditional Chinese and Western medicine treatment can achieve better results in controlling blood pressure as well as other cardiovascular risk factors. The mechanism of controlling of blood pressure may be associated with the improvement of insulin sensitivity due to the Yiqi Huaju intervention. TRIAL REGISTRATION IDENTIFIER： ChiCTR-TRC-11001633.

Modeling and control for hydraulic transmission of unmanned ground vehicle

Variable pump driving variable motor(VPDVM) is the future development trend of the hydraulic transmission of an unmanned ground vehicle(UGV).VPDVM is a dual-input single-output nonlinear system with coupling,which is difficult to control.High pressure automatic variables bang-bang(HABB) was proposed to achieve the desired motor speed.First,the VPDVM nonlinear mathematic model was introduced,then linearized by feedback linearization theory,and the zero-dynamic stability was proved.The HABB control algorithm was proposed for VPDVM,in which the variable motor was controlled by high pressure automatic variables(HA) and the variable pump was controlled by bang-bang.Finally,simulation of VPDVM controlled by HABB was developed.Simulation results demonstrate the HABB can implement the desired motor speed rapidly and has strong robustness against the variations of desired motor speed,load and pump speed.

Baroreflex dysfunction in chronic kidney disease

Chronic kidney disease （CKD） patients have high cardiovascular mortality and morbidity. The presence of traditional and CKD related risk factors results in exaggerated vascular calcification in these patients. Vascular calcification is associated with reduced large arterial compliance and thus impaired barorefex sensi-tivity （BRS） resulting in augmented blood pressure （BP） variability and hampered BP regulation. Barorefex plays a vital role in short term regulation of BP. This review discusses the normal barorefex physiology, methods to assess baroreflex function, its determinants along with the prognostic significance of assessing BRS in CKD patients, available literature on BRS in CKD patients and the probable patho-physiology of barorefex dysfunction in CKD.

Association of blood pressure variability with target organ damage in older patients with essential hypertension

Background:Although multiple measures of blood pressure variability(BPV)have been proposed,whether they are better than mean blood pressure in predicting target organs is unclear.We aimed to determine the relationship between short term BPV and target organ injury.Methods:This study was a retrospective study,and 635 inpatients in the Department of Cardiology from 2015 to 2020 were selected.We divided participants into four groups on the basis of the quartiles of BPV.One-way analysis of variance was used to compare the differences between the groups,and linear regression was used to analyze the relationship between BPV and target organ damage.Results:The average age of 635 patients was 74.36±6.50 years old.Among them,354 of 627 patients had diminished renal function(56.5%),221of 604 patients had associated left ventricular hypertrophy(36.6%),and 227 of 231 patients had carotid plaque formation(98.3%).The baseline data indicated significant differences in fasting glucose,total cholesterol,low-density lipoprotein,creatinine,glomerular filtration rate,sex,calcium channel blocker use,and the rate of diminished renal function.Multiple linear regression analysis showed that BPV was negatively correlated with renal injury(creatinine:r=0.306,p<0.01;estimated glomerular filtration rate:r=0.058,p<0.01),and BPV is positively correlated with cardiac injury(r=0.083,p<0.01).Elevated BPV was not found to be associated with vascularinjury.Conclusion:Renal function decreases with increasing BPV and left ventricular mass increases with increasing BPV.

Autonomic and cardiovascular effects of pentobarbital anesthesia during trigeminal stimulation in cats

Stimulation of the trigeminal nerve can elicit various cardiovascular and autonomic responses;however,the effects of anesthesia with pentobarbital sodium on these responses are unclear.Pentobarbital sodium was infused intravenously at a nominal rate and the lingual nerve was electrically stimulated at each infusion rate.Increases in systolic blood pressure（SBP） and heart rate（HR） were evoked by lingual nerve stimulation at an infusion rate between 5 and 7 mg？kg 21 ？h 21.This response was associated with an increase in the low-frequency band of SBP variability（SBP-LF）.As the infusion rate increased to 10 mg？kg 21 ？h 21 or more,decreases in SBP and HR were observed.This response was associated with the reduction of SBP-LF.In conclusion,lingual nerve stimulation has both sympathomimetic and sympathoinhibitory effects,depending on the depth of pentobarbital anesthesia.The reaction pattern seems to be closely related to the autonomic balance produced by pentobarbital anesthesia.

＂One-for-several＂ rotor VVVF Technique apply to water injection station

In the process of oilfield water injection volume of injection allocation often appear with the pump displacement situation does not match, the widespread adoption of stator frequency technology allows the pump displacement and volume of injection allocation phase matching. But the technology in pump class load application speed range is limited, there is still a reflux valve control blind area,＂ turn off undead＂ problem. ＂ One-for-several＂ rotor frequency Technique in water injection station application, solved the control blind area problem, the full realization of the variable frequency close return voltage injection, at the same time, the successful implementation of the slip power efficient feedback. Stable water injection pressure of the system, and the electric energy is saved, satisfy the oilfield high efficiency, fine water needs, has a high application value.

Influence of HbA1c on short-term blood pressure variability in type 2 diabetic patients with diabetic nephropathy

The aim of this study was to understand the characteristics of blood pressure （BP） variability in subjects with diabetic nephropathy （DN）, and identify the probable predictors affecting BP variability. Fifty-one chronic kidney disease （CKD）-hypertensive patients without diabetes （NDN group） and sixty type 2 diabetic patients with overt DN （DN group） were enrolled in this study. The values of short-term BP variability were obtained from 24 h ambulatory BP monitoring （ABPM）. Variance analysis or nonparametric analysis revealed that 24-h systolic BP variability and night- time systolic BP variability of the DN group were significantly higher than those of the NDN group [（12.23±3.66） vs. （10.74±3.83） mmHg, P〈0.05; （11.23±4.82） vs. （9.48±3.69） mmHg, P〈0.05]. Then the patients of the DN group were divided into two groups according to glycated hemoglobin （HbAlc） level： Group A （HbA1c〈7%） and Group B （HbA1c〉7%）, and the t-test showed that patients in Group B had larger 24-h diastolic, daytime diastolic, and nighttime systolic/diastolic BP variability compared with Group A. In the DN group, partial correlation analysis revealed that HbAlc exhibited a strong association with 24-h diastolic, daytime diastolic, nighttime systolic and diastolic BP vari- ability （P〈0.001, P〈0.001, P〈0.05, and P〈0.001, respectively）. Taken together, larger short-term BP variability was detected in hypertensive type 2 diabetic patients with overt nephropathy and renal insufficiency. It may imply that the optimal BP variability level could benefit from a better glycaemic control.

Association between dietary sodium intake and blood pressure variability in Chinese patients with hypertension

Background:The association between dietary sodium intake and blood pressure variability(BPV)in hypertensive patients remains unclear.The objective of this study was to demonstrate whether dietary sodium intake is a predictor of elevated BPV in Chinese patients with hypertension.Methods:A total of 235 patients with essential hypertension were enrolled in the Department of Cardiology,Chinese People’s Liberation Army(PLA)General Hospital in 2018 to 2019,all of whom underwent 24-h ambulatory blood pressure monitoring.BPV was calculated as the standard deviation(SD),coefficient of variation(CV),variation independent of mean(VIM)of blood pressure measurements,respectively,and divided into diurnal systolic BPV(SBPV),diurnal diastolic BPV(DBPV),nocturnal SBPV,and nocturnal DBPV.24-h urine samples were collected to measure 24-h urine sodium excretion,which represents dietary sodium intake.The relationship between dietary sodium intake and BPV was analyzed by using Spearman correlations and multiple linear regression analysis.Results:Nocturnal SBPV-SD,CV,VIM,and nocturnal DBPV-SD in the high urine sodium excretion group were significantly higher than those in the medium and low urine sodium excretion groups,whereas diurnal SBPV-SD,CV,VIM,diurnal DBPV-SD,CV,VIM,and nocturnal DBPV-CV,VIM were not.Using the Spearman correlation analysis,we found a linear correlation between 24-h urine sodium excretion and nocturnal SBPV-SD,CV,VIM(SD,r=0.22,P=0.001;CV,r=0.17,P=0.009;VIM,r=0.16,P=0.020),nocturnal DBPV-SD(r=0.21,P=0.001),respectively.After further adjusting for confounding factors by multiple linear regression,the positive correlations remained between 24-h urine sodium excretion and nocturnal SBPV-SD,CV,VIM(SD,β=0.224,P<0.001;CV,β=0.211,P=0.001;VIM,β=0.213,P=0.001),nocturnal DBPV(SD,β=0.215,P=0.001),respectively.Conclusions:Dietary sodium intake is associated with nocturnal SBPV in Chinese patients with hypertension.