Experimental study on the degree and damage-control mechanisms of fuzzy-ball-induced damage in single and multi-layer commingled tight reservoirs

Fuzzy-ball working fluids(FBWFs)have been successfully applied in different development phases of tight reservoirs.Field reports revealed that FBWFs satisfactorily met all the operational and reservoir damage control requirements during their application.However,the damage-control mechanisms and degree of formation damage caused by fuzzy-ball fluids have not been investigated in lab-scale studies so far.In this study,the degree of fuzzy-ball-induced damage in single-and double-layer reservoirs was evaluated through core flooding experiments that were based on permeability and flow rate indexes.Additionally,its damage mechanisms were observed via scanning electron microscope and energy-dispersive spectroscopy tests.The results show that:(1)For single-layer reservoirs,the FBWF induced weak damage on coals and medium-to-weak damage on sandstones,and the difference of the damage in permeability or flow rate index on coals and sandstones is below 1%.Moreover,the minimum permeability recovery rate was above 66%.(2)For double-layer commingled reservoirs,the flow rate index revealed weak damage and the overall damage in double-layer was lower than the single-layer reservoirs.(3)There is no significant alteration in the microscopic structure of fuzzy-ball saturated cores with no evidence of fines migration.The dissolution of lead and sulfur occurred in coal samples,while tellurium in sandstone,aluminum,and magnesium in carbonate.However,the precipitation of aluminum,magnesium,and sodium occurred in sandstone but no precipitates found in coal and carbonate.The temporal plugging and dispersion characteristics of the FBWFs enable the generation of reservoir protection layers that will minimize formation damage due to solid and fluid invasion.

Situational continuity-based air combat autonomous maneuvering decision-making

In order to improve the performance of UAV's autonomous maneuvering decision-making,this paper proposes a decision-making method based on situational continuity.The algorithm in this paper designs a situation evaluation function with strong guidance,then trains the Long Short-Term Memory(LSTM)under the framework of Deep Q Network(DQN)for air combat maneuvering decision-making.Considering the continuity between adjacent situations,the method takes multiple consecutive situations as one input of the neural network.To reflect the difference between adjacent situations,the method takes the difference of situation evaluation value as the reward of reinforcement learning.In different scenarios,the algorithm proposed in this paper is compared with the algorithm based on the Fully Neural Network(FNN)and the algorithm based on statistical principles respectively.The results show that,compared with the FNN algorithm,the algorithm proposed in this paper is more accurate and forwardlooking.Compared with the algorithm based on the statistical principles,the decision-making of the algorithm proposed in this paper is more efficient and its real-time performance is better.

Ultrasound-guided stellate ganglion blockade: an appealing tactic for cardiac electrical storm

Ventricular arrhythmia(VA)is a life-threatening cardiac emergency.When VA occurs three times or more within 24 h and interventions are required,it is defined as an electrical storm(ES)characterized by refractoriness and recurrence.[1]For patients with implantable cardioverter defibrillator(ICD),the notion is redefined as no fewer than three appropriate and separate(at least 5 min for each interval)ICD interventions given within 24 h.

Relationship between red blood cell distribution width levels and atrial fibrillation in hypertensive patients

Background Information on the relationship between red blood cell distribution width(RDW)and atrial fibrillation(AF)in patients with essential hypertension are scarce.The study aimed to assess the relationship between AF and RDW in hypertensive patients.Methods We enrolled 432 hypertensive patients,including 350 AF patients and 82 patients as controls.Patients'demographic,clinical,laboratory and echocardiographic characteristics were recorded.The AF patients were further divided into the persistent and paroxysmal AF subgroups.Electrocardiograms were monitored to identify the cardiac rhythm during blood sampling,and based on the rhythm,the paroxysmal AF group was categorized into the presence(with AF rhythm during blood sampling)and absence(with sinus rhythm during blood sampling)groups.Results The AF group had elevated RDW levels than the controls(12.7%±0.8%vs.12.4%±0.7%,P=0.002),and the persistent AF subgroup had higher RDW levels than the paroxysmal AF subgroup(12.9%±0.8%vs.12.6%±0.8%,P=0.007).Furthermore,in the paroxysmal AF group,the presence group had higher RDW levels than the absence group(13.0%±0.6%vs.12.5%±0.9%,P=0.001).There was no significant difference in RDW levels between the persistent AF subgroup and presence group of the paroxysmal AF subgroup(P=0.533)and between the absence group of the paroxysmal AF subgroup and control group(P=0.262).In multivariate regression analysis,in hypertensive patients,the presence of AF rhythm is an independent predictor for increased RDW concentration(P=0.001).Conclusions The RDW may be associated with the presence of AF rhythm,which implies the importance of maintaining the sinus rhythm in hypertensive patients.

Association between big endothelin-1 and CHADS2/CHA2DS2-VASc scores in non-valvular atrial fibrillation

Background Endothelial function,as measured by big endothelin-1(ET-1),has been demonstrated to be useful in predicting adverse long-term events in patients with cardiovascular disease.Nevertheless,there are little data about the association between big ET-1 and thromboembolism risk in atrial fibrillation(AF).We aimed to investigate the relationship between big ET-1 and CHADS2/CHA2DS2-VASc scores used for evaluating thromboembolic risk in patients with non-valvular AF.Methods The study population consisted of 238 consecutive AF patients(67.6%with paroxysmal AF and 32.4%with persistent AF).The patients were divided into two groups(high-or low-intermediate risk group)based on CHADS2 and CHA2 DS2-VASc scores(score≥2 or<2,respectively).Clinical,laboratory,and echocardiographic parameters were evaluated,and the CHADS2/CHA2DS2-VASc scores were compared between groups.The association between big ET-1 levels and CHADS2/CHA2DS2-VASc score was assessed.Multivariate logistic regression analysis was performed to identify independent predictors of CHADS2/CHA2DS2-VASc scores.Results The high CHADS2/CHA2DS2-VASc score group had older age,higher big ET-1 levels,and enlarged left atrial diameter than the low CHADS2/CHA2DS2-VASc score group(P<0.05).Multiple logistic regression analysis revealed that big ET-1 level was an independent determinant of high CHADS2/CHA2DS2-VASc scores[odds ratio(OR)=2.545 and OR=3.816;both P<0.05].Conclusions Our study indicates that in non-valvular AF,big ET-1 was significantly correlated with CHADS2/CHA2DS2-VASc scores and an independent predictor of high CHADS2/CHA2DS2-VASc scores.Big ET-1 may serve as a useful marker for risk stratification in this setting.

Ablation strategies for arrhythmogenic right ventricular cardiomyopathy: a systematic review and meta-analysis

Background Catheter ablation for ventricular tachycardia(VT) in patients with arrhythmogenic right ventricular cardiomyopathy(ARVC) has significantly evolved over the past decade. However, different ablation strategies showed inconsistency in acute and long-term outcomes. Methods We searched the databases of Medline, Embase and Cochrane Library through October 17, 2019 for studies describing the clinical outcomes of VT ablation in ARVC. Data including VT recurrence, all-cause mortality, acute procedural efficacy and major procedural complications were extracted. A meta-analysis with trial sequential analysis was further performed in comparative studies of endo-epicardial versus endocardial-only ablation. Results A total of 24 studies with 717 participants were enrolled. The literatures of epicardial ablation were mainly published after 2010 with total ICD implantation of 73.7%, acute efficacy of 89.8%, major complication of 5.2%, follow-up of 28.9 months, VT freedom of 75.3%, all-cause mortality of 1.1% and heart transplantation of 0.6%. Meta-analysis of 10 comparative studies revealed that compared with endocardial-only approach, epicardial ablation significantly decreased VT recurrence(OR: 0.50;95% CI: 0.30–0.85;P = 0.010), but somehow increased major procedural complications(OR: 4.64;95% CI: 1.28–16.92;P = 0.02), with not evident improvement of acute efficacy(OR: 2.74;95% CI: 0.98–7.65;P = 0.051) or all-cause mortality(OR: 0.87;95% CI: 0.09–8.31;P = 0.90). Conclusion Catheter ablation for VT in ARVC is feasible and effective. Epicardial ablation is associated with better long-term VT freedom, but with more major complications and unremarkable survival or acute efficacy benefit.

OptiVol fluid index predicts acute decompensation of heart failure with a high rate of unexplained events

Background Intrathoracic impedance monitoring has emerged as a promising new technique for the detection of impending heart failure (HF). Although false positive episodes have been reported in case reports and clinical trials, the efficacy and false positive rate in real-world practice remain unclear. Objective The aim of this study is to investigate the utility and reliability of the OptiVol alert feature in clinical practice. Methods We continuously recruited patients who underwent implantable cardioverter-defibrillator (ICD) or cardiac re-synchronization therapy with defibrillator (CRT-D) implantation with feature of intrathoracic impedance monitoring system in our center from Sep. 2010 to Oct. 2012. Regular in-office follow-up were required of all patients and the following information was collected at each visit: medical history, device interrogation, N-terminal pro-brain natriuretic peptide (NT-proBNP) measurement and an echocardiogram. Worsening HF was defined as hospitalization or the presentation of signs or symptoms of HF. Results Forty three patients (male:76.7%, mean age:57 ± 15 years, left ventricular ejection fraction (LVEF):33%± 14%) were included in this observational study. Fifty four alert events and 14 adjudicated worsening HF were detected within 288 ±163 days follow-up. Eleven (20.4%) alert episodes were associated with acute cardiac decompensation in 9 patients with a positive predictive value of 78.6%. Forty three audible alerts showed no connection to worsening HF. The unexplained alerts rate was 79.6%and 1.27 per person-year. Thirty seven alarm alerts were detected in patients with EF<45%, among which 9 accompanied with HF, 17 alerts detected in patients with LVEF≥45%and 2 associated with HF. There was no sig-nificant difference between the two groups (9/37 vs. 2/17;P=0.47). Conclusions Patients with normal or nearly normal left ventricular systolic function also exhibited considerable alert events. The OptiVol fluid index predicted worsening cardiac events with a high unex-plained detection rate, and any alert must therefore be analyzed with great caution. Efforts to improve the specificity of this monitoring sys-tem represent a significant aspect of future studies.

Fast rate （≥ 250 beats/min） right ventricular burst stimulation is useful for ventricular tachycardia induction in arrhythmogenic right ventricular cardiomyopathy

在 arrhythmogenic 的主要挑战的 BackgroundOne 恰好室的心肌症(ARVC ) 脱离是室的心悸亢进(vt ) non-inducibility。学习试图估计是否快评价(&#x02265；250 beats/min ) 恰好室的爆炸刺激为在与有经历了 electrophysiological 学习的临床的持续 vt 的 ARVC.MethodsNinety 一个连续 ARVC 病人一起的病人感应的 vt 是有用的被注册。刺激协议如下在正确的室的顶和流出道被实现：走 A，直到两倍额外刺激；步 B，有低率的增长刺激(&#x0003c；250 beats/min ) ；步 C，爆炸刺激与快评价(&#x02265；250 beats/min ) ；步 D，与 76 个病人全部的 isoproterenol.ResultsA 的静脉内的注入上面重复了所有步有的可诱导的 vt (83.5%) ，在哪个之中 49 被步 C 导致， 15 被步 B 导致， 8 和 4 由步 A 和 D 分别地。临床的 vt 在 60 个病人(65.9%) 被导致。仅仅二自发地停止的室的纤维性颤动被步 C 导致。Multivariate 分析证明在湾穴节奏下面的更狭窄的基线 QRS 持续时间独立地与 vt non-inducibility 被联系(或：1.1；95% CI：1.0-1.1；P = 0.019 ).ConclusionFast 率(&#x02265；250 beats/min ) 恰好室的爆炸刺激为在 ARVC 病人感应的 vt 提供一个有用补加的方法。

Factors influencing adherence to non-vitamin K antagonist oral anticoagulants in the early period after atrial fibrillation catheter ablation in China

Anticoagulants are routinely prescribed in the first several weeks after atrial fibrillation(AF)catheter ablation.Nonvitamin K antagonist oral anticoagulants(NOACs)have been recommended over warfarin for their superiority.Unlike warfarin need regular clinical visit to perform blood test,NOACs are more patient friendly.But the lack of routine medical contact may lead to poor adherence.Strict adherence to anticoagulant treatment is essential for both efficacy and safety.Considering NOACs are increasingly commonly used in China,it is therefore necessary to evaluate the adherence of NOACs after AF catheter ablation.The purpose of this research was to investigate the treatment adherence and identify factors that could improve the quality of anticoagulation.