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Left atrial (LA) function and mechanical dispersion changes in breast cancer patients treated with chemotherapy remain unclear.LA function and LA mechanical dispersion in breast cancer patients would be impaired after chemotherapy.This single-center retrospective study included 91 consecutive breast cancer patients treated with chemotherapy and 30 controls. Patients were examined by echocardiography three times at intervals. Conventional parameters, left ventricular strain, LA strain, and LA mechanical dispersion were evaluated and compared.LA strain during reservoir phase (LASr), conduit phase (LAScd), and contraction phase (LASct) all decreased markedly after chemotherapy and were lower than those of the controls (all p .01). The standard deviation of time to peak positive strain during LA reservoir phase corrected by R-R interval (LA SD-TPSr) was significantly increased after chemotherapy and was higher than that of the controls (p .001). The change of LA function was expressed as Δ. Multivariate linear regression analyses showed that LAVIp (0.399, 95% confidence interval [CI]: 0.610, 1.756, p = .000) was independently associated with ΔLASr, LAPEF (-0.325, 95% CI: -45.123, -10.676, p = .002) and age (0.227, 95% CI: 0.021, 0.350, p = .027) were independently associated with ΔLAScd, and LAVImax (0.341, 95% CI: 0.192, 0.723, p = .001) was independently associated with ΔLASct. LAVImax (0.505, 95% CI: 0.000, 0.001, p = .039) and mitral E (-0.256, 95% CI: 0.000, 0.000, p = .024）were independently associated with ΔLA SD-TPSr.Mechanical function of LA declined after chemotherapy in breast cancer patients. With the decrease of LA mechanical function, LA mechanical dispersion assessed by two-dimensional speckle-tracking echocardiography increased significantly, and its clinical value needs to be further studied.

The fatigue tests of Chinese RPV steel (A508-3) were carried out under the simulated primary coolant environment of AP1000 which is a kind of 3rd generation nuclear power plant. The effects of temperature, strain rate and dissolved oxygen (DO) on fatigue life were analyzed. During the fatigue test, the material exhibited a cyclic hardening followed by cyclic softening behavior, with no obvious cyclic stability region. In logarithmic coordinates, the S–N curve showed a bilinear relationship. As the strain amplitude increased from 0.2 to 0.6%, the fatigue life approximately decreased from 105 to 3 × 102. The environmental correction factor (Fen), which is defined as the ratio of life in air at room temperature to that in the primary coolant environment, decreases as the temperature decreases from 321 to 150 °C. The Fen also decreases as the DO decreases from 0.6 to 0.03 ppm while it increases as the strain rate decreases from 1 to 0.0004%/s. Compared with the NUREG6909 model, the presented model is more applicable for fatigue life prediction of Chinese A508-3 steel.

Objective We examined the associations among the circadian rhythms of blood pressure (BP), heart rate (HR) and left atrial function in essential hypertensive patients. Methods The study included 237 essential hypertensive patients who completed 24-h ambulatory BP, HR monitoring and two-dimensional speckle tracking echocardiography (2DSTE). The strain and strain rate images were studied, and the following parameters were measured: left atrial reservoir strain and strain rate (LAS-S and LASR-S), left atrial conduit strain and strain rate (LAS-E and LASR-E), and left atrial booster strain and strain rate (LAS-A and LASR-A). The left atrial stiffness index (LASI) was identified as the ratio of E/e' to LAS-S. All participants were divided into three groups according to the percentage of nocturnal BP dipping (dippers, nondippers and reverse dippers). Results The LASI was significantly higher in BP reverse dippers than in dippers and nondippers. LAS-S, LAS-E and LASR-E were significantly lower in BP reverse dippers than dippers and nondippers. Multivariate logistic regression analysis demonstrated that age, night-time mean SBP and the percentage of nocturnal HR decline were independently related to an increased LASI. Conclusion Impairment of the left atrial reservoir and conduit functions was correlated with abnormal BP and HR circadian rhythms in hypertension. Increased left atrial stiffness was associated with night-time SBP and the percentage of nocturnal HR decline.

Zhitong Li1 *, Lifei Pan1 *, Yawen Deng,1 Quanbo Liu,2 Tesfaldet H Hidru,1 Fei Liu,1 Chenglin Li,1 Tao Cong,1 Xiaolei Yang,1 Yunlong Xia1 1Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian, People’s Republic of China; 2Department of Respiratory Medicine, Shengjing Hospital of China Medical University, Shenyang, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xiaolei Yang; Yunlong Xia, Email 15942456079@yeah.net; yunlong_xia@126.comPurpose: Left atrial thrombus (LAT)/left atrial spontaneous echo contrast (LASEC) still exists in CHA2DS2-VASc score-defined low/borderline risk population. The purpose of this study is to explore the risk factors that associate with LAT/SEC and to create a nomogram to predict LAT/SEC risk in NVAF patients with low/borderline CHA2DS2-VASc scores.Patients and Methods: A total of 834 NVAF patients with complete data on transesophageal echocardiography (TEE) were included in this study. Univariate and multivariate logistic regression analyses were performed to identify the risk factors that associate with LAT/SEC, and a nomogram was established based on the results. Receiver operating characteristic curve (ROC), calibration curve and decision curve analysis were performed to verify the predictive power of nomogram.Results: The rates for LAT/SEC for the training and validation cohorts were 84 (14.7%) and 30 (11.4%), respectively. Independent factors including age, left ventricular ejection fraction (LVEF), left atrial diameter (LAD), smoke, non-paroxysmal AF (NPAF), and E/e’ were considered to construct the nomogram for LAT/SEC. The AUC for nomogram was 0.839 and 0.811 in the training and validation cohorts, respectively. The calibration and decision curve analysis showed that the nomogram had a good prediction capacity and would be clinically useful.Conclusion: Age, LVEF, LAD, smoke, NPAF, and E/e’ are independently associated with LAT/SEC in NVAF patients with low/borderline CHA2DS2-VASc scores. The nomogram that incorporates these six variables effectively predict LAT/SEC risk in NVAF patients with low/borderline CHA2DS2-VASc scores.Keywords: left atrial thrombus, spontaneous echo contrast, atrial fibrillation, nomogram, CHA2DS2-VASc score

Background The SCN11A gene, encoded Nav1.9 TTX resistant sodium channels, is a main effector in peripheral inflammation related pain in nociceptive neurons. The role of SCN11A gene in the auditory system has not been well characterized. We therefore examined the expression of SCN11A in the murine cochlea, the morphological and physiological features of Nav1.9 knockout (KO) ICR mice. Results Nav1.9 expression was found in the primary afferent endings beneath the inner hair cells (IHCs). The relative quantitative expression of Nav1.9 mRNA in modiolus of wild-type (WT) mice remains unchanged from P0 to P60. The number of presynaptic CtBP2 puncta in Nav1.9 KO mice was significantly lower than WT. In addition, the number of SGNs in Nav1.9 KO mice was also less than WT in the basal turn, but not in the apical and middle turns. There was no lesion in the somas and stereocilia of hair cells in Nav1.9 KO mice. Furthermore, Nav1.9 KO mice showed higher and progressive elevated ABR threshold at 16 kHz, and a significant increase in CAP thresholds. Conclusions These data suggest a role of Nav1.9 in regulating the function of ribbon synapses and the auditory nerves. The impairment induced by Nav1.9 gene deletion mimics the characters of cochlear synaptopathy.

In this paper, a comparative study of the very-high-cycle fatigue (VHCF) behavior of railway wheel steel under axial loading and rolling contact loading was conducted. Fatigue tests were performed with an ultrasonic fatigue test machine under axial loading, and the fracture surfaces from the fatigue tests and shattered rims taken from the failed railway wheels were observed. The wheel steel under axial loading presents a VHCF behavior with Mode I crack, and that under rolling contact loading is a VHCF behavior with mix Mode II-III crack. For the VHCF behavior with Mode I crack ,surface and interior crack initiation occurred with equal probability at both low and high stress levels and produced a dual linear S-N curve since the value of fatigue limits for the surface and interior crack initiation are close. For the VHCF behavior with mix Mode II-III crack, cracks were initiated from the interior Al O inclusion and the fatigue life was beyond 10 cycles. Fatigue bands were observed on the fracture surface under rolling contact loading. The ferrite nanograins formed due to the stress state of shear plastic strain with a large compressive stress. The formed nanograins were softer than the matrix caused by the redistribution of the carbon.

Background: The predictive power of the CHADS2 and CHA2DS2-VASc scores for the presence of Left atrial thrombus (LAT)/ spontaneous echo contrast (SEC) in non-valvular atrial fibrillation (NVAF) is modest. The aim of this analysis is to define clinical and ultrasonic variables associated with LAT/SEC and to propose nomograms for individual risk prediction.Methods: Data on 1,813 consecutive NVAF patients who underwent transesophageal echocardiography (TEE) from January 2016 to January 2021 were collected. The univariate and multivariate logistic regression analyses were used to construct a nomogram. We examined the predictive ability of the risk scores by calculating the area under the curve (AUC). Moreover, the performance of the nomogram was assessed with respect to calibration, discrimination, and clinical usefulness.Results: LAT/SEC was found in 260 (21.0%) and 124 (21.6%) patients in the training and validation cohorts, respectively. On multivariate analysis, independent factors for LAT/SEC were Age, left atrial diameter (LAD), left ventricular ejection fraction (LVEF), hypertension (HTN), previous stroke or transient ischemic attack, Non-paroxysmal AF and a nomogram was built based on these variables. The calibration curve for the probability of LAT/SEC showed good prediction agreement with actual observation. The nomogram achieved good concordance indexes of 0.836 and 0.794 in predicting LAT/SEC in the training and validation cohorts, respectively. Decision curve analysis demonstrated that the nomogram would be clinically useful.Conclusions: In this study, a nomogram was constructed that incorporated six characteristics of NVAF patients. The nomogram may be of great value for the prediction of LAT/SEC in NVAF patients.

We examined the effects of phosphorus (P) levels on photosynthetic and P/Fe traits of soybean under the stress of low Fe and their genotypic differences, to provide a theoretical basis for rational application of P and Fe fertilizer. Six P-efficient and six P-inefficient soybean varieties screened in the early stage were used as experimental materials. Four treatments of P:Fe ratio were set, including 0:30, 30:30, 150:30 and 300:30 (μmol·L为了明确低铁胁迫下磷素用量对大豆光合和磷/铁性状的影响及基因型差异,为磷、铁肥的合理施用提供理论依据,以前期筛选的6个磷高效基因型和6个磷低效基因型大豆为供试材料,设4个P∶Fe配比处理,分别为0∶30、30∶30、150∶30和300∶30(μmol·L

Tension-compression and tension-tension fatigue tests were conducted on a high-strength steel and a titanium alloy in the very-high-cycle fatigue (VHCF) regime. A shared interior crack initiation mechanism for high strength steel and titanium alloy was proposed based on the common nanograins and facet formation, i.e., (i) cleavage of local brittle microstructure; (ii) gradual growth of originated cracks (facets), and the coalescence of adjacent facets, facets disappear and nanograins form for the cyclic pressing in the cases of tension-compression fatigue and (iii) coalesced crack forming a main crack. The experimental results indicate that the stress ratio magnitude has a substantial effect on the fatigue strength, which decreases with the increasing of stress ratio. The tendency of the S-N curves from low cycle fatigue to VHCF regime is similar for the high-strength steel and the titanium alloy with different stress ratios. It is shown that the relationship of fatigue strength, fatigue life, inclusion size and stress ratio in the VHCF of high-strength steel and Ti-6Al-4V are correlated by the Sun model. The predicted results are in good agreement with the experimental data.

Due to the improvement of the wear property, rolling contact fatigue including shattered rim and shelling are the main failure causes of the high-speed railway wheels. In this paper, shattered rim and shelling occurred on the service wheels of the China Railway High-speed (CRH) trains were systematically investigated. The recorded data of the last ten years CRH operation indicated that all shattered rims and shelling were detected with serving >106 km (corresponding to the fatigue life 107–109 cycles) which is very-high-cycle fatigue (VHCF). The crack initiation region of shattered rim located at the depth of 10–25 mm from the tread, while that of shelling located at the depth

OBJECTIVE The aim of this study was to investigate the value of real time three-dimensional transesophageal echocardiography (RT3DTEE) in percutaneous closure of the left atrial appendage (LAAC). In addition, this study also explored the change in the size of the left atrial appendage (LAA) from 24 hours before the operation to just before implantation during the operation. METHODS AND RESULTS In a retrospective study, 32 patients underwent two-dimensional transesophageal echocardiography (2DTEE) and RT3DTEE 24 hours prior to operation and during operation. The maximal LAA orifice diameter (by 2DTEE, 22.7 ± 2.7 vs 24.6 ± 2.2 mm, P

With the rapid development of big data, big data research in the security protection industry has been increasingly regarded as a hot spot. This article mainly aims at solving the problem of predicting the tendency of juvenile delinquency based on the experimental data of juvenile blindly following psychological crime. To solve this problem, this paper proposes a rough ant colony classification algorithm, referred to as RoughAC, which first uses the concept of upper and lower approximate sets in rough sets to determine the degree of membership. In addition, in the ant colony algorithm, we use the membership value to update the pheromone. Experiments show that the algorithm can not only solve the premature convergence problem caused by stagnation near the local optimal solution but also solve the continuous domain and combinatorial optimization problems and achieve better classification results. Moreover, the algorithm has a good effect on predicting classification and can provide guidance for predicting the tendency of juvenile delinquency.

Background and Purpose: Cancer patients treated with anthracyclines are susceptible to atrial fibrillation (AF) with unknown mechanisms. Due to sudden and unpredictable features of AF, detection or prediction of anthracycline-induced AF at early phase is difficult. Experimental Approach: Breast cancer patients (post-surgery) with an anthracycline-containing regimen were recruited for echocardiography at pre-, and 3 and 6 months post-chemotherapy. Mice were injected with doxorubicin or vehicle and the following parameters were determined: left atrial diameter, electrical transmission, AF inducibility. Meanwhile, oxidative stress, cardiomyocyte size, vacuolization, inflammation and fibrosis were measured in mouse atria. The therapeutic effect of dexrazoxane on doxorubicin-induced changes in the aforementioned parameters were also determined. Key Results: Whilst ventricular parameters and functions were unchanged in cancer patients pre- and post-chemotherapy, strain and strain rate of left atrial reservoir function and conduit function were decreased at 3 months post-chemotherapy vs pre-chemotherapy. Doxorubicin-induced atrial dilatation and susceptibility to AF occurred in mice prior to onset of ventricular dysfunction. Doxorubicin-induced AF was via inducing structural remodeling (i.e. cardiomyocyte death, hypotrophy and vacuolization) and electrical remodeling (i.e. reduction and redistribution of connexin 43) in the atrium, which was effectively prevented by dexrazoxane. Atrial remodeling and AF inducibility were induced after doxorubicin injection, which can be inhibited by dexrazoxane. Conclusions and Implications: Clinically, we tested whether anthracycline-induced early atrial remodeling in patients could be detected by echocardiography. Experimentally, we investigated the mechanisms of doxorubicin-induced atrial remodeling and AF in mice, and the protective effect of the free radical scavenger dexrazoxane.