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In this study, we propose an innovative approach that enhances the performance of the backpropagation (BP) neural network in predicting the low‐cycle fatigue life of Ti‐6Al‐4V alloy by improving the dung beetle optimization (DBO) algorithm with the maximin Latin hypercube design (MLHD) strategy. To address the challenges posed by complex geometric components under different temperature conditions, this research employs finite element simulation to expand the limited experimental dataset and utilizes these data to further guide and optimize the MLHD_DBO_BP model. Test results indicate that the proposed MLHD_DBO_BP model significantly outperforms the traditional finite element method (FEM) and other neural network models in terms of fatigue life prediction performance. This research demonstrates the effectiveness of machine learning models that combine experimental and simulation data in predicting the low‐cycle fatigue life of Ti‐6Al‐4V alloy. [ABSTRACT FROM AUTHOR]

Ferromagnetic order in 2D2D materials has triggered widespread interest because of their applications in spintronic devices. Monolayer 1T‐VSe2, as a recently emerged candidate of 2D2D ferromagnetic material, exhibits complicated behaviors that contradict the theoretical predictions. In this work, a systematic investigation is presented on the evolution of the transport properties in VSe2 thin flakes controlled by gate voltage. Notably, for the first time, a paramagnetic‐to‐ferromagnetic transition is realized in a VSe2 thin flake using a field‐effect transistor setup with solid ion conductor of polycrystalline Li1+x+yAlx(Ti2−yGey)P3−zSizO12 serving as the gate dielectric. The Curie temperature determined from the electrical transport measurements is ≈40 K. The electric‐field‐controlled ferromagnetism in exfoliated VSe2 flakes provides an excellent platform for developing advanced spintronics as well as investigating unusual emergent physics in 2D systems. [ABSTRACT FROM AUTHOR]

Background: Mid‐ventricular obstruction (MVO) is a rare subtype of hypertrophic cardiomyopathy (HCM) but it is associated with ventricular arrhythmia. The relationship between MVO and non‐sustained ventricular tachycardia (NSVT) in HCM patients is unknown. Hypothesis: The severity of MVO increases the incidence of NSVT in patients with hypertrophic obstructive cardiomyopathy (HOCM). Methods: Five hundred and seventy‐two consecutive patients diagnosed with HOCM in Fuwai Hospital between January 2015 and December 2017 were enrolled in this study. Holter electrocardiographic and clinical parameters were compared between HOCM patients with and without MVO. Results: Seventy‐six (13.3%) of 572 patients were diagnosed with MVO. Compared to patients without MVO, those with MVO were much younger, and had a higher incidence of syncope, greater left ventricular (LV) posterior wall thickness, a higher percentage of LV late gadolinium enhancement, and higher prevalence of NSVT. Furthermore, the prevalence of NSVT increased with the severity of MVO (without, mild, moderate or severe: 11.1%, 18.2%, 25.6%, respectively, p for trend <.01). Similarly, the prevalence of NSVT differed among patients with isolated LV outflow tract (LVOTO), both MVO and LVOTO, and isolated MVO (11.1%, 21.3%, 26.6%, respectively, p for trend =.018). In addition to age, diabetes, left atrial diameter, and maximal wall thickness, multivariate analysis revealed the presence of MVO as an independent risk factor for NSVT (Odds ratio 2.69; 95% confidence interval 1.41 to 5.13, p =.003). Conclusions: The presence and severity of MVO was associated with higher incidence of NSVT in HOCM patients. [ABSTRACT FROM AUTHOR]

Rationale: Monitoring plasma concentration and adjusting doses of antituberculosis (TB) drugs are beneficial for improving responses to drug treatment and avoiding adverse drug reactions. A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to measure the plasma concentrations of 14 anti‐TB drugs: ethambutol, isoniazid, pyrazinamide, levofloxacin, gatifloxacin, moxifloxacin, prothionamide, linezolid, rifampin, rifapentine, rifabutin, cycloserine, p‐aminosalicylic acid, and clofazimine. Methods: Human plasma was precipitated by acetonitrile and was subsequently separated by an AQ‐C18 column with a gradient elution. Drug concentrations were determined using multiple reaction monitoring in positive ion electrospray ionization mode. According to pharmacokinetic data of patients, the peak concentration ranges and the timing of blood collection were determined. Results: Intra‐ and interday precision was < 14.8%. Linearity, accuracy, extraction recovery, and matrix effect were acceptable for each drug. The stability of the method satisfied different storage conditions. Conclusions: The method allowed the sensitive and reproducible determination of 14 frequently used anti‐TB drugs which has already been of benefit for some TB patients. [ABSTRACT FROM AUTHOR]

To achieve high‐precision position control for the active magnetic bearing high‐speed flywheel rotor system (AMB‐HFRS), a novel control strategy based on inverse system method and extended two‐degree‐of‐freedom (2‐DOF) proportional–integral–derivative (PID) controller is proposed in this study. First, the inverse system method is employed to decouple the AMB flywheel rotor system with strong non‐linear and coupling, into four independent subsystems. Subsequently, extended 2‐DOF PID controllers are used to regulate the decoupled subsystems, to obtain good performances of disturbance rejection and tracking simultaneously. In the extended 2‐DOF PID controller, a differential signal is produced by a velocity observer to improve the ability of against noise. Finally, the characteristics of stability, tracking, disturbance rejection and robustness of the control strategy proposed are analysed in theory, and its ability and effectiveness to control the radial position of the AMB‐HFRS are further studied by simulations and experiments. It is shown that the control strategy proposed can keep the AMB‐HFRS suspending stably from static state to the speed of 24,000 rpm, has the advantages of good tracking, high disturbance rejection, strong robustness and good ability of against noise. [ABSTRACT FROM AUTHOR]

To eliminate the influence of gyroscopic effect on system stability and to improve the control performances for the active magnetic bearing (AMB) high‐speed flywheel rotor system, a novel control strategy based on the modal separation and inverse system method is proposed. The translational motions and rotational motions of the AMB flywheel rotor system are firstly decoupled by the modal separation, then the rotational motions are decoupled by the inverse system method, so that the AMB flywheel rotor system, which is a multivariable and strong coupled system, is decoupled into four subsystems. Finally, the subsystems are regulated by four two‐degrees‐of‐freedom (2‐DOF) internal model controllers, respectively. Furthermore, the stability, tracking and robustness of the novel control strategy are analysed theoretically, and its effectiveness on vibration control of the AMB high‐speed flywheel rotor system is further investigated by simulations and experiments. The results show that the novel control strategy can achieve stable suspension and effectively suppress the vibration of the AMB high‐speed flywheel rotor system from static state to 24,000 rpm, with the advantages of high stability, strong robustness, and good performances of tracking and disturbance rejection simultaneously. [ABSTRACT FROM AUTHOR]

Background: Filamin C (FLNC) mutation was reported as a cause of HCM, with a high probability of sudden cardiac death. However, the mutation profile of FLNC, and its relationship with phenotypic expression in HCM, remains to be elucidated. Methods: In this study, FLNC gene was sequenced in 540 HCM patients and 307 healthy controls. Results: We found that 39 (7.2%) patients carried FLNC mutations, with a similar frequency to that of controls (4.2%, p = 0.101). Pedigree analysis showed that mutations were not well segregated with HCM. The baseline characteristics between HCM patients, with and without mutations, were comparable. FLNC mutations did not increase the risk for either all‐cause mortality (HR 0.746, 95% CI 0.222–2.295, p = 0.575) or cardiac mortality (HR 0.615, 95% CI 0.153–1.947, p = 0.354) in HCM patients during a follow‐up of 4.7 ± 3.2 years. Moreover, there was no significant difference in survival free from sudden cardiac arrest (HR 0.721, 95% CI 0.128–3.667, p = 0.660) and heart failure (HR 0.757, 95% CI 0.318–1.642, p = 0.447). Conclusions: FLNC mutations were common in both HCM patients and healthy population. The pathogenicity of FLNC mutations detected in HCM patients and its association with the clinical outcomes should be cautiously interpreted. As a previously reported cause of HCM, FLNC mutation is found to be very common in the healthy population and HCM patients in this study. Generally, FLNC mutation does not cause HCM, and it does not increase later mortality and morbidity in HCM patients. [ABSTRACT FROM AUTHOR]

Identification and composite control of Hammerstein system with unknown order linear dynamics and a static hysteresis non‐linearity modelled by Preisach operator is investigated. The order of linear dynamics is firstly determined by Hankel matrix approach and then a blind identification is implemented to identify the linear dynamics based on the over‐sampling output measurements only. Then a novel deterministic approach is proposed to identify the Preisach model for hysteresis non‐linearity, which is devoted to identify a triangle matrix. This novel approach needs less dimensions to obtain Preisach density function than other existing methods. Finally, a composite control consisting of discrete inverse model‐based controller (DIMBC) and discrete adaptive sliding mode controller (DASMC) is developed to achieve tracking control. The composite control can reduce the reaching time of DASMC and improve the robustness of DIMBC. Experiments based on a turntable servo system demonstrate the effectiveness of the proposed identification and control methods. [ABSTRACT FROM AUTHOR]

Background Obesity is an established cardiovascular risk factor in patients with hypertrophic cardiomyopathy. Postoperative atrial fibrillation (POAF) is one of the most common complications after surgery in patients with obstructive hypertrophic cardiomyopathy (OHCM). We aimed to determine the impact of body mass index (BMI) on the occurrence of POAF in patients with OHCM who underwent septal myectomy. Methods and Results In all, 712 OHCM patients without previous atrial fibrillation who underwent septal myectomy were identified. Patients were stratified into 3 groups based on BMI. Of these, 224 (31.5%) had normal weight (BMI<24 kg/m 2 ), 339 (47.6%) were overweight (BMI, 24 to <28 kg/m 2 ), and 149 (20.9%) were obese (BMI≥28 kg/m 2 ). Overweight and obese patients had increased levels of left atrial diameter ( P <0.001) and left ventricular end-diastolic diameter ( P <0.001), compared with patients with normal weight. Among 184 patients (25.8%) developing POAF, 32 cases (14.3%) occurred in the normal weight group, 100 cases (29.5%) occurred in the overweight group, and 52 cases (34.9%) occurred in the obese group ( P <0.001). Logistic regression analysis indicated that overweight (odds ratio [OR]: 2.161, 95% CI, 1.333-3.503; P =0.002) or obesity (OR, 2.803; 95% CI, 1.589-4.944; P <0.001), age (OR, 1.037; 95% CI, 1.018-1.057; P <0.001), and left atrial diameter (OR, 1.060; 95% CI, 1.027-1.095; P <0.001) were independently associated with the occurrence of POAF in patients with OHCM. Conclusions Overweight and obesity are strong predictors of POAF in patients with OHCM. Strategies aimed at lowering BMI may be a potential way to prevent POAF.

Background: Myocardial bridging (MB) is commonly treated in patients with hypertrophic cardiomyopathy. However, whether and how MB should be treated in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent septal myectomy remain unclear., Methods: A total of 823 adults with HOCM who underwent septal myectomy at the Fuwai Hospital from 2011 to 2017 were retrospectively studied., Results: Overall, 31 events occurred: 24 patients died and 7 had nonfatal myocardial infarction (MI). The 3-year cumulative event-free survival of all-cause death (97.9% vs. 100% vs. 100% vs. 98.4%, p = .89) and cardiovascular death (98.3% vs. 100% vs. 100% vs. 98.4%, p = .63) were similar among the four groups (non-MB, coronary artery bypass grafting [CABG], unroofing, untreated, respectively). However, the 3-year cumulative event-free survival of nonfatal MI (100% vs. 97.5% vs. 98.0% vs. 89.9%, p < .001) and combined endpoints (97.9% vs. 97.5% vs. 98.0% vs. 88.4%, p = .02) were significantly lowest in untreated MB (non-MB, CABG, unroofing, untreated, respectively). Cox regression analysis indicated that untreated MB was a significant independent predictor of combined endpoints (hazard ratio: 4.06, 95% confidence interval: 1.60-10.32, p < .001). Moreover, 49 patients underwent coronary artery computed tomography 1 year after surgery. The patency rate of the saphenous vein graft was significantly higher than that of the left internal mammary artery (13.3% vs. 84.2%, p < .001). No MB was detected in the unroofing group., Conclusions: Surgical MB treatment could be beneficial and performed safely during septal myectomy. Myocardial unroofing is the recommended treatment for MB, and unroofing when technically possible may be preferable for long-term outcomes., (© 2020 Wiley Periodicals LLC.)

Background and Aim: Recently alcohol septal ablation (ASA) has emerged as an alternative treatment for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) and a subgroup of HOCM patients with previous ASA may need myectomy. However, subsequent outcome and mechanism of residual obstruction has not been determined. This study aims to determine outcome after myectomy and mechanism of residual obstruction in HOCM patients with previous ASA., Methods: From February 2009 to June 2017, 38 HOCM patients with previous ASA underwent surgical septal myectomy at our institution. Seventy-six patients who underwent surgical septal myectomy initially were included as the comparison group through one-to-two propensity score matching method., Results: Fourteen available cardiac magnetic resonance images revealed inferior location and small area of infarcted myocardium induced by ASA in 12 patients and outside targeted location in two patients. During follow-up (median, 2.4; maximum, 7.8 years), event-free survival at 7 years was 83.2% in the previous ASA group and 94.6% in the comparison group, respectively (P = 0.0378). Multivariable analysis indicated previous ASA (hazard ratio, 4.28; 95% confidence intervals [CI], 1.20-15.26; P = 0.025) and postoperative left ventricular end-diastolic diameter (hazard ratio, 1.14; 95% CI, 1.05-1.23; P = 0.002) were independent predictors of adverse events., Conclusions: This study demonstrated that uncontrollable extent and location of infarcted myocardium induced by ASA may attribute to residual obstruction after previous ASA, and the long-term event-free survival after myectomy was inferior. It may provide special precaution to patient selection and the increased number of ASA practiced worldwide., (© 2019 Wiley Periodicals, Inc.)

Background: The mid-term outcome of patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing coronary artery bypass graft (CABG) is unclear., Materials and Methods: We studied 44 patients with HOCM and coronary artery disease (CAD) who underwent septal myectomy and CABG) between 2011 and 2017. The control group was matched in a ratio of 4:1 based on age, sex, body mass index, hypertension, and chest pain., Results: Compared to patients without CAD, patients with CAD had a higher long-term cardiovascular mortality rate (0.6% vs 6.8%, P = 0.03; hazard ratio [HR] = 8.16, 95% confidence interval [CI]: 1.27-74.48, P = 0.03). In addition, 10 out of 176 (5.7%) patients without CAD and nine out of 44 (20.5%) patients with CAD achieved the secondary endpoints (progressive heart failure, unexplained syncope, stroke, atrial fibrillation, and myocardial infarction) (HR = 2.89, 95%CI: 1.03-8.12, P = 0.04). The 5-year survival rate and cardiovascular event-free survival rate were significantly higher in patients without CAD than in those with CAD (97.4% vs 93.9%, P = 0.03; 89.2% vs 80.1%; P = 0.04). In the multivariate analysis, presence of CAD, New York Heart Association class, and left atrial diameter were predictors of combined cardiovascular events when adjusted for age and male sex., Conclusions: The cardiovascular death and cardiovascular events are significantly increased in patients with HOCM and CAD who underwent CABG at the time of septal myectomy., (© 2019 The Authors. Journal of Cardiac Surgery Published by Wiley Periodicals, Inc.)