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Precipitable water vapour (PWV) plays an important role in weather prediction, hydrological cycles and climate change. In this study, a physics-based algorithm was proposed to retrieve PWV over lan...

Re-ablation has an important role in the control of recurrent atrial fibrillation (AF) post the first ablation. The present study was to report the outcome of AF re-ablation for patients who recurred after initial ablation, and to characterize the clinical and electrophysiological features predicting recurrence after redo ablation. From January 2012 to May 2017, patients undergoing re-ablation for AF in our hospital were consecutively enrolled. Clinical and electrophysiological data for the initial and second procedure were collected retrospectively and prospectively, respectively. All patients were followed up for one year and recurrences during the time were reported. Totally 259 patients entered into the analysis (age, 58.4 ± 10.5 years; 169 men). At the end of one-year follow-up, 85 patients recurred with atrial arrhythmias (32.8%). In the multivariate analysis, higher CHA2DS2-VASC score (p = 0.023, 95% CI 1.03–1.53) and shorter time to recurrence after the initial ablation (p = 0.001, 95% CI 0.93–0.98) were clinical factors predictive of one-year recurrence after the repeat ablation. The reconnection of the right pulmonary vein (PV) (p = 0.034, 95% CI 0.31–0.96) and the absence of not eliminated non-PV trigger at the second procedure (p = 0.032, 95% CI 1.25–142.80) independently predicted the better re-ablation outcome. About one-third of patients recurred after one year following re-ablation. CHA2DS2-VASC score and time to recurrence after the initial ablation were independent clinical factors predicting recurrence. Also, electrophysiological findings during the repeat ablation (the right PV reconnection and absence of not eliminated non-PV trigger) were associated with better outcome during one year of follow-up.

PRKAG2 cardiomyopathy is a rare progressive disease characterized by increased ventricular wall thickness and preexcitation. Dysfunction of the protein 5'-AMP-activated protein kinase (AMPK) plays a decisive role in the progression of ventricular lesions. Although patients with the

Background: New-onset atrial fibrillation (AF) after ablation of typical atrial flutter (AFL) is not rare. This study aimed to investigate the predictive value of electrocardiographic parameters on new-onset AF post-typical AFL ablation.Methods: A total of 158 consecutive patients (79.1% males, mean age 57.8 ± 14.3 years) with typical AFL were enrolled between January 2012 and August 2017 in this single-center study. Patients with a history of AF before ablation were excluded. ECGs during sinus rhythm (SR) and AFL were collected. The duration of the negative component of flutter wave in lead II (DFNII), proportion of the DFNII of the total circle length of AFL (DFNII%), amplitude of the negative component of flutter wave in lead II (AFNII), duration (DPNV1), and amplitude (APNV1) of negative component of the P wave in lead V1, and P wave duration in lead II (DPII) during sinus rhythm were measured.Results: During a median follow-up of 26.9 ± 11.8 months, 22 cases (13.9%) developed new-onset AF. DFNII was significantly longer in patients with new-onset AF compared to patients without AF (114.7 ± 29.6 ms vs. 82.7 ± 12.8 ms, p < 0.0001). AFNII was significantly lower (0.118 ± 0.034 mV vs. 0.168 ± 0.051 mV, p < 0.0001), DPII (144.21 ± 23.77 ms vs. 111.46 ± 14.19 ms, p < 0.0001), and DPNV1 was significantly longer (81.07 ± 16.87 ms vs. 59.86 ± 14.42 ms, p < 0.0001) in patients with new-onset AF. In the multivariate analysis, DFNII [odds ratio (OR), 1.428; 95% CI, 1.039–1.962; p = 0.028] and DPII (OR, 1.429; 95% CI, 1.046–1.953; p = 0.025) were found to be independently associated with new-onset AF after typical AFL ablation.Conclusion: Parameters representing left atrial activation time under both the SR and AFL were independently associated with new-onset AF post-typical AFL ablation and may be useful in risk prediction, which needs to be confirmed by further prospective studies.

Background The literature on laminopathy with ventricular phenotype is extensive. However, the pathogenicity of LMNA variations in atrial lesions still lacks research. Objective To characterize the atrial phenotype and possible mechanisms in a large Chinese family with heart-hand syndrome carrying LMNA missense variant in rod 2B domain (c.1003C>T p.R335W). Methods Clinical characteristics were collected based on the pedigree investigation. Comprehensive functional analyses, including molecular dynamic simulation, cellular, and animal functional assays, determined the pathogenicity in atrial myopathy. Results In the pedigree investigation, 6/13 of the mutation carriers showed heterogeneous cardiac phenotypes, and eight carriers also had brachydactyly. In silico molecular dynamics simulations predicted increased binding energy of R335W mutant lamin A. Atrial cardiomyocytes (HL-1, hiPSC-derived atrial cardiomyocytes) expressing R335W showed abnormal nuclear morphology, compromised DNA repair, and dysfunctional contraction. Adult zebrafish expressing mutant lamin A showed increased P wave duration in the electrocardiogram, decreased A peak velocity in echocardiography, and atrial lesions under the transmission electron microscope. Conclusion The LMNA p.R335W mutation leads to a familial heart-hand syndrome characterized by an overlapping phenotype of prominent atrial lesions and brachydactyly. The unstable lamin dimerization and impaired DNA repair are possible mechanisms underlying cardiac phenotypes. Our findings consolidated the genetic role in the course of atrial arrhythmias and cardiac aging, which is helpful to the diagnosis and treatment of cardiac laminopathy.

Aims Idiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux. This study was to report a group of idiopathic epicardial VAs remote from the summit and crux areas. Methods In total, 9 patients (6 males, mean age 32±13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site. Results VAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A “QS” type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p

The Visible and Infrared Spin-Scan Radiometer (VISSR) onboard the Fengyun-2 (FY-2) satellite can provide valuable thermal infrared observations to help create a precipitable water vapor (PWV) product with high spatial and temporal resolutions. The current FY-2/VISSR PWV product in operation is produced by using a traditional two-band physical split-window (PSW) method, which produces low quality results under dry atmospheric conditions. Based on the sensitivity characteristics of FY-2F/VISSR water vapor channel and two split-window channels to atmospheric water vapor, this study developed a new, robust operational PWV retrieval algorithm for FY-2F to improve the operational precision of the current PWV product. The algorithm uses a modified three-band PSW method, which adds a scale for the water vapor channel in the improved three-band PSW method. Integrated PWV products from the radiosonde data in 2016 are used here to validate the precision of the PWV retrieved by the modified three-band and traditional two-band PSW methods. The mean bias, root mean square error (RMSE), and correlation coefficient of the PWV retrieved by the modified three-band PSW method are 0.28 mm, 4.53 mm, and 0.969, respectively. The accuracy is much better than the PWV retrieved by the two-band method, whose mean bias, RMSE, and correlation coefficient are 12.67 mm, 29.35 mm, and 0.23. Especially, in mid- or high-latitude regions, the RMSE of the PWV is improved from 10 to 2 mm by changing the inversion in the two-band method to the modified three-band PSW method. Furthermore, the modified three-band PSW results show a better consistency with the radiosonde PWV at any zonal belt and season than the two-band PSW results. This new algorithm could significantly improve the quality of the current FY-2F/VISSR PWV product, especially at sites where the actual PWV are lower than 15 mm.

The role of catheter ablation as an adjunct and alternative to ICD implantation is not known in patients at risk for recurrent ventricular tachycardia (VT) and sudden cardiac death (SCD) across Asia. Patients with nonischemic etiologies of cardiomyopathy, which are highly prevalent in Asia, have not been previously enrolled in randomized trials of VT ablation. To evaluate whether preemptive catheter ablation in patients with monomorphic VT and an indication for ICD implantation results in improved clinical outcomes compared to ICD implantation with standard medical therapy alone. To examine the natural history of ablation outcomes in the absence of background ICD therapy in patients that refuse randomization. The PAUSE-SCD study (NCT02848781) is a prospective, multi-center, randomized controlled trial enrolling patients with structural heart disease (EF

BACKGROUND Variation of atrial electromechanical delay (AED) in early phase after catheter ablation in patients with atrial fibrillation (AF) is lacking. METHODS Fifty-five consecutive patients restored sinus rhythm after ablation was included. Echocardiography was performed at 4 h, 1 day, and 3 days after radiofrequency catheter ablation, and AED was measured simultaneously by echocardiography with pulse Doppler imaging and pulse wave tissue Doppler imaging. RESULTS AED parameters were significantly longer in the nonparoxysmal atrial fibrillation (NPAF) group than in the paroxysmal atrial fibrillation (PAF) group at each checking point after ablation (P

Peripheral blood mononuclear cells (PBMCs) were harvested and reprogramed to induced pluripotent stem cells (iPSCs) from a 46-year-old male patient with familial dilated cardiomyopathy and atrial fibrillation via a non-integrating system. A missense mutation in the LMNA gene (c.1003C > T) was identified by whole-exome sequencing and verified by Sanger sequencing. The pluripotency, differentiation potential, and karyotype of this cell line were also tested. This model is helpful to study the phenotype, mechanism, and therapy for laminopathy.

Background and Purpose: Complete P wave disappearance (CPWD) in patients without atrial fibrillation is an uncommon clinical phenomenon. We aimed to study the relationship between CPWD and thromboembolism. Methods: Between July 2007 and December 2018, consecutive patients with CPWD on surface ECG and 24-hour Holter recording were recruited into the study from 4 centers in China. All recruited patients underwent transesophageal echocardiography or cardiac computed tomography to screen for atrial thrombus. Atrial electrical activity and scar were assessed by electrophysiological study (EPS) and 3-dimensional electroanatomic mapping. Cardiac structure and function were assessed by multimodality cardiac imaging. Results: Twenty-three consecutive patients (8 male; mean age 48.5±14.7 years) with CPWD were included. Only 3 patients demonstrated complete atrial electrical silence with atrial noncapture. Thirteen patients who had invasive atrial endocardial mapping demonstrated extensive scar. Pulse-wave mitral inflow Doppler demonstrated absent and dampened A waves in 18 and 5 patients, respectively. Pulse-wave tricuspid inflow Doppler showed absent and dampened A waves in 19 and 4 patients, respectively. Upon recruitment, 8 patients had previous stroke and 3 patients had atrial thrombus. Warfarin was prescribed to all patients. During median follow-up of 42.0 months, 2 patients developed massive ischemic stroke due to warfarin discontinuation. Conclusions: Our study suggested that CPWD reflects extensive atrial electrical silence and significantly impaired atrial mechanical function. It was strongly associated with thromboembolism and the clinical triad of CPWD-atrial paralysis-stroke was proposed. Anticoagulation should be recommended in such patients.

Human-induced pluripotent stem cell (hiPSC) technology and directed cardiac differentiation technology can provide a continuous supply of cells for disease modeling, drug screening, and cell therapy. However, two-dimensional (2D) cells often fail to faithfully reflect the physiological structure and function of the heart. Considering the contractile function is the most critical and easy-to-understand function of cardiomyocytes, the engineered cardiac tissues (ECT) with mechanical properties may serve as an appropriate three-dimensional (3D) platform for drug evaluation. At present, there are various methods to generate ECTs, some of which are quite costly. In the present study, we proposed that human foreskin fibroblast (HFF) cells, as a cost-effective and accessible cell source, can promote the compaction and remodeling of ECTs. The HFFs derived ECTs displayed stable structural and functional characteristics with a higher performance-to-price ratio. Moreover, both ECTs made from atrial and ventricular cardiomyocytes showed an excellent drug response, demonstrating that the ECT with HFFs as an easy and reliable platform for drug evaluation.

Element exchange and enrichment during fluid-rock interactions are common, providing potentially novel proxies to trace hydrocarbon migration in addition to the traditional organic geochemistry tracers. However, the processes, mechanisms, and geological and geochemical fingerprints of these interactions are complex, hampering the applications of hydrocarbon migration tracers. To investigate such interactions, we conducted a petrological, mineralogical, and in situ and bulk geochemical study of authigenic quartz and whole-rock samples from the Mahu Sag, northwestern Junggar Basin, northwest China. We found that dissolution, clay and chlorite formation, and overgrowth occurred on quartz grains in hydrocarbon fluid migration pathways, suggestive of strong fluid-rock interactions. In situ quantitative elemental analysis of quartz grains revealed elemental enrichment (e.g., Mn, Fe, Al, Sr, and W) in quartz overgrowth rims compared with their cores, indicating that migration of hydrocarbon-bearing fluids in reservoirs may promote elemental exchange between fluids and minerals. Whole-rock geochemical analysis showed that decreasing contents of some elements may reflect the direction of hydrocarbon-bearing fluid migration and can be monitored with three geochemical proxies, which are the MnO contents and MnO/Zr and Y/Ho ratios. Our data provide new constraints on fluid-rock interactions in petroleum reservoirs and have implications for using inorganic geochemical methods to trace hydrocarbon migration.

BackgroundIdiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux.ObjectiveTo report a group of idiopathic epicardial VAs remote from the summit and crux areas.MethodsIn total, 9 patients (6 males, mean age 32{plus minus}13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site.ResultsVAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A "QS" type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p

Primary fibrotic atrial cardiomyopathy (PF-ACM) is a novel type of cardiomyopathy characterized by primary atrial fibrosis with arrhythmogenicity and increased stroke risk without ventricular myocardium involvement. However, genetic analysis regarding PF-ACM and genotype-phenotype correlations is lacking. A cohort of PF-ACM patients was recruited and followed up. Whole-exome sequencing (WES) was applied, and genes were screened using a cardiovascular disease (CVD)-related gene panel. Echocardiography and cardiac magnetic resonance (CMR) were performed. The pathogenicity of the identified mutations was evaluated using in silico analysis. Thirty-three unrelated patients were referred for WES. Thirty-three rare variants of 19 CVD-related genes were identified in 21 patients, with 10 patients harboring more than one variation. TTN was the most frequent gene observed. Further analysis demonstrated that variations in sarcomeric (SV) or non-sarcomeric (NSV) genes were found in 16 and 10 patients, respectively. Patients carrying variants regardless of SV or NSV had larger left atrial dimensions determined by echo and larger left atrium areas determined by CMR. There was no discrepancy in disease severity between SV carriers and NSV carriers. Our genetic investigation into PF-ACM has identified several genetic culprits, providing further insight into its underlying pathophysiology and emphasizing a potential role for genetic testing for this condition.

INTRODUCTION Atrial fibrosis is associated with atrial fibrillation (AF) recurrence after ablation. This study aims to determine the relationship between soluble ST2 (sST2), a profibrotic biomarker, and AF recurrence after radiofrequency catheter ablation (RFCA). METHODS AF patients referred for RFCA were consecutively included from October 2017 to May 2019. Baseline characteristics were collected, and sST2 levels were determined before ablation. Left atrial substrate mapping was performed after circumferential pulmonary vein isolation under sinus rhythm, and substrate was modified in low-voltage zones. A second procedure was recommended under recurrence. RESULTS Two hundred fifty-eight patients (146 males, average age 61.0 ± 8.8) were included. After a medium follow-up of 13.5 months, 52 patients (20.2%) had recurrence and received a second procedure. Preoperative sST2 level in patients with recurrence was significantly higher than that in patients without (31.3 ng/mL vs 20.3 ng/mL, P

Six machine-learning approaches, including multivariate linear regression (MLR), gradient boosting decision tree, k-nearest neighbors, random forest, extreme gradient boosting (XGB), and deep neural network (DNN), were compared for near-surface air-temperature (Tair) estimation from the new generation of Chinese geostationary meteorological satellite Fengyun-4A (FY-4A) observations. The brightness temperatures in split-window channels from the Advanced Geostationary Radiation Imager (AGRI) of FY-4A and numerical weather prediction data from the global forecast system were used as the predictor variables for Tair estimation. The performance of each model and the temporal and spatial distribution of the estimated Tair errors were analyzed. The results showed that the XGB model had better overall performance, with R2 of 0.902, bias of −0.087°C, and root-mean-square error of 1.946°C. The spatial variation characteristics of the Tair error of the XGB method were less obvious than those of the other methods. The XGB model can provide more stable and high-precision Tair for a large-scale Tair estimation over China and can serve as a reference for Tair estimation based on machine-learning models.

Air Temperature(T air ),a basic meteorological observation element, is an essential meteorological parameter in physiology, hydrology, meteorology, environment, etc. The T air data ,which is characterized by high precision, is of great significance for the greenhouse effect, land surface processes and so on. With the advent of high performing imaging instrument onboard geostationary satellites such as Advanced Geostationary Radiation Imager(AGRI) onboard FY-4A of China, it provides high spatial and temporal resolution data. To estimate T air from such high-resolution data, this paper presents an effective method for estimation T air based on AGRI data. Different machine learning algorithms–-random forest (RF), k-nearest neighbors(KNN) and extreme gradient boosting(XGB)–-are evaluated for estimation of T air under clear sky conditions in the Southwest of China. For the training dataset, the two infrared brightness temperatures of AGRI (BT 12 and BT 13 ), digital elevation model(DEM), latitude and longitude, surface pressure, time and relative humidity(RH) are selected. The T air data obtained by National Centers for Environmental Information(NCEI), evaluates different machine learning algorithm performance in the Southwest of China. The results show that the performance of the XGB model is better than RF and KNN with a correlation coefficient (R) of 0.977, a mean bias of -0.036□,and the root mean square error (RMSE) of 1.266□.

Southern Shaanxi refers to the southwestern part of Shaanxi, and from the west to the east of Shaanxi Province, there are three cities: Hanzhong, Ankang and Shangluo. The annual precipitation data of 8 meteorological stations in the southern part of Shaanxi Province from 1977 to 2017 were selected, and the area was analyzed by EOF (empirical orthogonal function method). The results show that the EOF method can well reveal the temporal and spatial distributions of precipitation field. For the southern part of Shaanxi Province, the first two eigenvectors reveal two typical distribution fields, which are global and eastwest patterns. Its cumulative contribution rate is 79.90%. In general, the eigenvectors of the two fields are expressed as the western region is larger than the eastern region. And high-value centers appear in Hanzhong City. The analysis of the time coefficient corresponding to the eigenvectors shows that the precipitation fields in the southern part of Shaanxi Province mainly show four types. Which includes the wetter in the whole region, the drier in the whole filed, the wetter in west and drier in east, and the wetter in east and drier in west. Compared to the statistical results of 41 year, these results were consistent with the typical precipitation fields

With the global warming, CO (carbon monoxide) as an indirect greenhouse gas, plays a crucial role in the contribution of greenhouse effect. High concentration of CO in the air will do harm to people's health. Based on the CO total column data detected by the Tropospheric Monitoring Instrument (TROPOMI) on Sentinel-5 Precursor satellite, which was launched by the European Space Agency (ESA) on 13 October 2017. This study analyzes the seasonal variable characteristics of the CO total column from June 2018 to May 2019 in China and the spatial distribution of the CO total column in North China, Central China, Sichuan Basin, Qinghai-Tibet Plateau and Pearl River Delta. The high values areas are mainly located in the eastern part of China with high population activity and developed industry, while the Qinghai- Tibet Plateau area and the northwest area are generally low. Selecting the area where the CO total column was significantly enhanced in Hebei province on 24 May, 2018, and monitoring the pollution in the following days. The results show that the TROPOMI data product is a good way to show the source of pollution and has the ability to detect local hot spots.

Sinus node inability or conduction disorders of its surrounding atrial myocardium cause sinus node dysfunction (SND). This study aimed to characterize right atrium (RA) substrates and long-term atrial lead performance after pacemaker implantation in non-senile SND patients.Eighteen SND patients (53.3 ± 9.6 years) controlled by 18 age-matched supraventricular tachycardia patients were consecutively enrolled. The P-wave amplitude (PWA) and P-wave duration (PWD) were measured on surface electrocardiography. Electroanatomic mapping was conducted to assess the bipolar voltage, complex signals, volume, and activation time of RA. Pacemaker implantation was performed in SND patients after mapping.Compared with controls, SND patients showed significant PWA reduction (0.13 ± 0.02 vs. 0.16 ± 0.04 mV, p = 0.017) and PWD prolongation (120.8 ± 15.2 vs. 105.2 ± 8.6 ms, p = 0.001). The RA endocardial voltage was lower (1.56 ± 0.78 vs. 2.57 ± 0.55 mV, p 0.001) and activation time was longer (112.1 ± 14.9 vs. 90.8 ± 12.4 ms, p 0.001) in the study group. Atrial lead was anchored at the lower atrial septum in one patient and failed in another due to extensive atrial scarring. During a median follow-up of 86 (57-88) months, one patient lost atrial capturing, and overall atrial sensing was significantly decreased (2.44 ± 1.16 vs. 1.87 ± 1.01 mV, p = 0.003).Atrial involvement was proved and the process was progressive in non-senile SND patients, as demonstrated by diffused RA lower voltage, slower conduction, and the decrease of the atrial lead sensing.

BACKGROUND Catheter ablation strategies for nonparoxysmal atrial fibrillation (NPAF) are in varied forms. The mechanisms that circumferential pulmonary vein isolation (CPVI) alone could achieve success in some of the patients with NPAF are not well studied. This study sought to assess the clinical outcome of only CPVI approach in NPAF patients without significant left atrium scar. METHODS AND RESULTS A total of 241 consecutive patients with NPAF undergoing an initial ablation procedure were studied. After CPVI, cavotricuspid isthmus ablation and direct current cardioversion, high-density atrial voltage mapping was performed during sinus rhythm. Transitional-voltage zone (TZ) was defined as 0.4-1.3 mV, and low-voltage zone (LVZ) as

Introduction Ventricular tachycardia (VT) acceleration due to antitachycardia pacing (ATP) therapy could be often observed in patients with implantable cardioverter defibrillator (ICD), which usually results in additional shock. However, few studies focused on the risk factors for VT acceleration caused by ATP therapy. The purpose of this study was to investigate risk factors for VT acceleration due to ATP delivery. Methods We retrospectively reviewed 1056 ATP episodes in 33 patients with structural heart diseases, of whom clinical characteristics and episodes details were evaluated. Results At individual patient level, number of VT morphologies recorded in electrograms during follow‐up was a risk factor with cutoff point of 1 (AUC 0.79, sensitivity 72.7%, specificity 77.3%, P

The Advanced Geostationary Radiation Imager (AGRI) onboard the first of China's next-generation geostationary meteorological satellite series (FY-4A) can provide high temporal resolution layer precipitable water (LPW) products. The AGRI LPWs, including total precipitable water (TPW), low (PW_low), middle (PW_mid), and high (PW_high) levels precipitable water, were first validated using a year radiosonde data. The results show that AGRI LPWs generally agree well with radiosonde derived LPWs, and the accuracy of LPWs demonstrates obvious spatial and temporal patterns. All LPWs at 00 UTC were underestimated and the root means square error (RMSE) of TPW, PW_low, PW_mid, and PW_high at 00 UTC are 6.04, 1.79, 3.32, and 2.68 mm, while the correlation coefficients (R) are 0.953, 0.958, 0.925, and 0.887, respectively. In contrast, AGRI LPWs at 12 UTC have no obvious under- or over-estimation, and shows a lower RMSE (1.49–4.4 mm) and a higher correlation (0.934–0.971). PW_high shows the largest mean absolute percentage error (MAPE) (>39%), while the MAPE of the other three LPWs is less than 29%. The RMSE of all four AGRI LPWs generally increase with water vapor, while R and MAPE decrease with water vapor. Thus, the AGRI LPWs over low latitudes with high water vapor content show larger RMSE while lower MAPE and R than mid and high latitudes. The accuracy of AGRI LPWs displays a seasonal pattern, with higher RMSE, lower R and MAPE in summer wet months, while lower RMSE, higher R and MAPE in winter dry months.

Introduction Detailed description of longstanding persistent accelerated idioatrial rhythm (AIAR) is lacking. This observational study investigated the clinical manifestations, electrophysiological characteristics, diagnosis, treatment and prognosis of this unusual arrhythmia. Methods and results Fifteen patients (11 males; average age 25.9±15.7 years) suspected with longstanding persistent AIAR were enrolled in our study. All patients had ECG, 24-hour Holter monitoring, isoproterenol provocation test, echocardiogram, and exercise treadmill test. Electrophysiological study (EPS) and catheter ablation were performed if necessary. The above noninvasive tests would be repeated during follow-up. Among the patients, 10 were asymptomatic; 5 had concomitant paroxysmal atrial tachycardia. Two asymptomatic patients had impaired left ventricular function. AIAR was observed throughout 24-hour Holter monitoring, showing chronotropic profile similar to sinus rhythm. Such AIAR exhibited competitive property with sinus rhythm (SR) when provoked by isoproterenol or during treadmill test. Twelve patients had EPS and 8 of them had successful ablation to eliminate AIAR. During a medium follow-up of 3.7 years, all patients were in well clinical course and preserved left ventricular dysfunction, and 3 patients spontaneously reverted to SR at 10-year follow-up. Conclusions Longstanding persistent AIAR is an unusual entity of atrial arrhythmias and in most situations a benign rhythm requiring no treatment. The clinical course will be worsened when AIAR develops rapid focal firing, is associated with focal atrial tachycardias or results in tachycardia-mediated cardiomyopathy, but can be resolved via catheter ablation. This article is protected by copyright. All rights reserved

This paper presents a new atmospheric precipitable water vapor (PWV) retrieval method based on three thermal infrared band observations from geostationary satellites. The proposed method is similar to the traditional physical split-window (PSW) retrieval technique, but a water vapor channel observation near 6.7 μm was included. Sensitivity analyses and simulation retrievals were carried out respectively according to the instrument characteristics of the Stretched Visible and Infrared Spin Scan Radiometer onboard FengYun-2G (SVISSR/FY-2G) and the Moderate Resolution Imaging Spectroradiometer aboard Terra (MODIS/Terra). The results indicate that the proposed 3-band algorithm can significantly reduce PWV retrieval errors caused by surface emissivity uncertainty and observation errors, especially in dry atmospheric conditions (i.e., PWV 2 ), root mean square error (RMSE), and bias between the SVISSR retrieved PWV and the radiosonde PWV are 0.87, 0.43 cm and 0.14 cm, respectively. The R 2 , RMSE and bias of the MODIS retrieved PWV are 0.89, 0.10 cm and − 0.042 cm, respectively, which are slightly better than the MODIS L2 thermal infrared and near-infrared PWV products.

Several satellites have been launched to monitor the increasing concentrations of greenhouse gases, especially CO2 and CH4 in the atmosphere, through back-scattered hyperspectral radiance in the shortwave infrared (SWIR) band. The vertical profiles of greenhouse gases and aerosol could strongly affect the results from these instruments. To investigate the effects of the vertical distribution of CO2 on uncertainty in SWIR satellite retrieval results, we conducted observations of the vertical profiles of CO2, CH4, and aerosol particles at 0.6–7 km above sea level using a Beechcraft King Air 350ER in Jiansanjiang (46.77° N, 131.99° E), Heilongjiang province, Northeast China, on August 7–12, 2018. The profiles from this aircraft captured a decrease in CO2 from 2 km to the minimum altitude due to uptake from vegetation at the surface in summer. CH4 measurements showed an average 0.5 ppm increase from 2.0 to 0.6 km, which may result from emissions from the large area of paddy fields below, and a constant mole fraction between 1.951 and 1.976 ppm was recorded at 2 km and above. Comparison of CO2 profiles from a new version of the carbon cycle data assimilation system Tan-Tracker (v1), retrievals from OCO-2 and aircraft measurements was conducted. The results from OCO-2 and the assimilation model system Tan-Tracker captured the vertical structure of CO2 above 3 km, whereas below 3 km, the values from OCO-2 and Tan-Tracker model were lower than those from in situ measurements. Column-averaged CO2 volume mixing ratios calculated from in situ measurements showed biases of −2.39 ± 2.02 ppm and −0.61 ± 0.49 % compared to OCO-2 retrievals.

The spatial and temporal distribution characteristics of high clouds over the Tibetan Plateau (TP) were studied using the Atmospheric Infrared Sounder (AIRS) and the GCM-Oriented CALIPSO Cloud Product (CALIPSO-GOCCP) monthly mean cloud products from 2007 to 2017. The high clouds over the TP are dominated by cirrus and show seasonal variation characteristics. There were two distinct areas with the high occurrence of cirrus clouds in the area (0°–60°N, 75°–103°E). One was located in the regions from the equator to 25°N, and the other was within the latitude belt from 30° to 40°N. From January to May, cirrus clouds mainly occurred in the central and northern parts of the TP (30° to 40°N), and the cirrus cloud fraction increased from January and reached its maximum (∼0.51) in April. From June to August, cirrus clouds mainly occurred in the southern part of the TP during summer. The cirrus clouds over the southern TP were relatively high (located in 10–17 km) and manifested northward and southward movements. The ice clouds in the southern TP are associated with plateau deep convection activities and abundant vapor transmitted by the Asian monsoon. Cirrus clouds over the northern and central TP may be relevant to the atmospheric lift by an approaching cold front and topographic lifting. Moreover, the high clouds below 11 km are dominated by opaque clouds, while the nonopaque (or thin) and opaque (or thick) clouds above 11 km are comparable.

Metamorphic rock reservoirs are special reservoirs that are quite different from traditional sedimentary rock reservoirs and contain rich hydrocarbon reserves. However, their lithofacies characteristics and reservoir properties are relatively underexplored, and the key factor in reservoirs is lithofacies. Based on core samples, thin sections, whole-rock analysis and well-log and seismic data, we evaluated the lithologies, petrological characteristics and reservoir properties of metamorphic rocks and then explored the main factors controlling reservoir formation and metamorphic rock quality in the Aryskum depression, South Turgay Basin, Kazakhstan. In this area, four types of lithofacies are identified: granitic gneiss (high DEN and CN, low GR), leptite (high GR and CN), gabbro (low GR and CN) and granite (high GR and low CN); among these rocks, granitic gneiss is widely distributed. The reservoir spaces of metamorphic rocks are divided into fractures and pores produced via metamorphism and structural movements. Fractures can be subdivided into structural fractures (SFs), dissolution fractures (DFs), cleavage microfissures (CMfs) and microfissures (Mfs), and pores include dissolved intergranular pores (DInterPs), dissolved intragranular pores (DIntrPs) and vugs (Vgs). Numerous SFs and DFs provide the main reservoir spaces for hydrocarbons. The reservoir quality of metamorphic rocks is primarily controlled by faults, fractures, lithofacies, minerals, dissolution and paleogeomorphology. Lithofacies and minerals are the internal factors that control dissolution and fragmentation, while paleogeomorphology and faults are the external factors that control fracture development. Leptite and granitic gneiss are high-quality reservoir lithofacies, and high paleogeomorphology areas and fault zones are the optimal locations for fractures and pores. Reservoir spaces undergo a series of repeated changes from formation to development, filling and reformation, and a comprehensive reservoir evolution model is proposed to illustrate the distribution of high-quality reservoirs. This study has scientific significance for investigating the reservoir-forming mechanisms of metamorphic rocks and practical applications for exploring and developing oil and gas fields in areas with metamorphic rocks.

The origin of fibrous calcite veins developed in organic-rich shales, has attracted great attentions. However the growth direction, formation temperature and stress state are still controversial. The calcite veins in organic-rich shale from lower Es3 to upper Es4 in the Jiyang Depression has been analyzed with electron backscatter diffraction technology (EBSD), which can characterize the microstructures and orientation of mineral crystals in situ. On the basis of core observation and microscopic identification of petrological characteristics, the longitudinal and horizontal profiles of calcite veins were measured by EBSD. Crystallographic information on calcite veins, obtained by pattern quality mapping, phase diagrams, grain distribution maps, Euler graphs, grain misorientations and pole figures, clarifies the origins of these veins. The results show that calcite crystals in calcite veins belong to the sharp-rhombohedral space lattice structure of the trigonal system. Calcite crystals have a preferred orientation on the longitudinal profile, while there is no obvious preferred orientation on the horizontal profile. On the longitudinal profile of calcite veins, the misorientation of calcite crystals is the cause of the interference colour and extinction difference of calcite crystals under orthogonal light. The crystal interference and extinction characteristics on both sides of middle line in calcite veins are different, indicating that the growth direction of calcite veins is syntaxial. A shallow burial environment is suggested for calcite veins initial forming by the evidence that crystal morphology of calcite in calcite veins is most in the shape of sharp-rhombohedron, and some of which have hexagonal prism shape. The average orientation difference of calcite veins on longitudinal and horizontal profiles indicates that the average orientation of calcite grains is inhomogeneous. The stress concentration of small grains is higher than that of large grains, and cracks are developed in the interior or on the border of calcite grains on the longitudinal profile, which indicates that calcite veins are formed in the stress environment of three directional extrusion circumstances.

Recent studies have shown that premature ventricular contractions (PVCs) could enlarge the heart, but its risk factors are incompletely understood as a single 24-hour recording cannot reflect the true PVC burden due to day-to-day variability. Our purpose was to investigate the effect of burden and origin sites on left ventricular (LV) function in patients with PVCs by 7-day Holter electrocardiography (ECG). From May 2012 to August 2013, 112 consecutive patients with PVCs were recruited from the authors' affiliated hospital. All patients received 2-dimensional transthoracic echocardiography, 12-lead routing ECG and 7-days Holter ECG. Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured. A total of 102 participants with PVCs were included in the final analysis. Origin of PVCs from the tricuspid annulus had the highest burden and NT-proBNP level. LV papillary muscle had a higher LV ejection fraction (EF) level and a lower LV end-systolic dimension (ESD) than other PVC foci (P

Radiosonde data collected from 83 stations in China from January to December 2012 were used to evaluate Moderate Resolution Imaging Spectroradiometer (MODIS) near-infrared (NIR) and thermal infrared (IR) total precipitable water vapour (PWV) products. The results indicate that MODIS NIR PWV products shows better agreement with radiosonde data than with IR PWV products, with the correlation coefficients up to 0.95. The root mean square errors (RMSEs) of NIR PWV range from 2 to 8 mm with different stations, which shows significant regional differences over China. The mean RMSE is about 5.03 mm (~35%) with a positive deviation of 2.56 mm (~18%), indicating the occurrence of a slight overestimation. Moreover, MODIS IR PWV during night-time has a better agreement with radiosonde PWV than that during daytime. The mean RMSE of IR PWV during daytime was ~6.02 mm (~42%), with a positive deviation of 1.54 mm (~11%). The mean RMSE of IR PWV during night-time was ~5.81 mm (~40%), with a negative deviation of approxim...

An algorithm for retrieving the surface pressure from oxygen A-band measurements in the future Chinese CO2 satellite (CarbonSpec/TanSat) was developed. The full physical radiative transfer model, vector radiative transfer model based on successive order of scattering, which is based on the successive order of scattering approach, was used to simulate the measurements of CarbonSpec/TanSat, as well as the kernel matrix in the inversion algorithm, and then the surface pressure and other related atmospheric parameters such as aerosol optical depth (AOD), surface albedo, and temperature were derived through optimal estimation theory. Sensitivities of the algorithm to surface albedo, solar zenith angle (SZA), viewing zenith angle (VZA), aerosol type, and AOD were investigated, and the results showed that the absolute error of retrieved surface pressure increases with decreasing surface albedo or increasing SZA and VZA. An accuracy of

A 58-year-old man presented with incessant atrial flutter (AFL) ([Figure 1A][1]); he had twice undergone unsuccessful attempts at ablation of the cavotricuspid isthmus (CTI) and was referred for ablation. Counterclockwise CTI-dependent AFL was verified by activation mapping ([Figures 1B and 1C][1

Feasibility of precipitable water vapor (PWV) retrieval from the ground-based infrared measurements in clear sky conditions was performed based on the radiative transfer simulation and retrieval experiments. The effects of aerosol, view zenith angle, and instrument spectral response function (SRF) on clear-sky infrared brightness temperature ( T sky) were analyzed. The results showed that atmospheric aerosol and SRF have obvious influence on T sky measurements and PWV retrievals. The relationship between T sky and PWV under low aerosol loading conditions is better than that of high aerosol loading conditions. Aerosol information is necessary for the inversion of high-precision PWV using a single-angle T sky measurement. T sky at the infrared atmospheric window (i.e., 10 to 12 μm) has a better exponential relationship with PWV than that covers 6.3 μm water vapor and 9.6 μm ozone absorption bands. Furthermore, a neural network (NN)-based PWV retrieval algorithm was proposed using dual-angle T sky measurements and near-surface air temperature ( T air). The results showed that the introduction of multiangle T sky can effectively reduce the influence of aerosol on PWV retrieval and improve the PWV retrieval accuracy. The determination coefficient, root-mean-square error, and bias of the NN model using dual-angle T sky (i.e., 0 deg and 30 deg) and T air were 0.989, 0.191, and 0.002 cm, respectively.

Background Right atrial tachycardia (AT) is a common arrhythmia postsurgical valve replacement in patients with rheumatic heart disease (RHD). However, the substrate and the mechanism of left AT in such patients and the ablation efficacy is less known. Methods and results Twenty-seven RHD patients with AT were enrolled in this study; nine of them (33%) had left AT. Five and four patients had left AT during the first and second procedure, respectively. A spontaneous scar in the left posterior wall was identified in all patients, and obvious anterior scar in three patients. Dual-roof-dependent AT was found in three patients and macroreentry AT surrounding right pulmonary vein was identified in one patient, two of whom had left anterior scar. Three patients had AT circuit going around the mitral annulus, one of whom had left anterior scar. Entrainment pacing at different sites confirmed the mechanism of these macroreentries. Two patients had a focal origin, one was localized in posterior wall at the edge of the scar and the other one was originated from the left septum with normal voltage. After a mean follow-up of 27.4 ± 7.9 months, the left AT group had a similar recurrence rate compared with the right AT group alone (67% vs 56%, P = 0.58). In the left AT group, 11% of patients had AT recurrence and 56% of patients developed atrial fibrillation. Conclusion Left atrial AT can occur in RHD patients postmitral valve replacement. Catheter ablation is feasible with high acute success rate. The incidence of late development atrial fibrillation is considerable after successful ablation.

Introduction Myocardium fibrosis is a hallmark of cardiomyopathy and a proposed substrate for cardiac arrhythmias. Nevertheless, fibrosis of atrial myocardium and fibrotic atrial cardiomyopathy has not been systemically addressed. Hypothesis We hypothesized that idiopathic, isolated, fibrotic atrial cardiomyopathy (IIF-ACM) is a specific cardiomyopathy, which is characterized by atrial fibrosis and related arrhythmias. Methods In the past 8 years, 34 patients (male 13, mean age 46.5±13.3 yrs) were diagnosed with IIF-ACM based on: 1) clinical evaluation; 2) cardiac image examination; and 3) electro-anatomic mapping detected atrial scarring. Serum biomarkers of collagen metabolism and cardiomyopathy-related genetic screening were performed. Tissue pathology and virus detections were done for two patients. Results During clinical evaluation, electric silent areas were detected in all patients by intra-cardiac electro-anatomical mapping. Among 34 patients, 26 presented with atrial tachycardia (AT), 5 with sick sinus syndrome (SSS) and 3 with atrial standstill. 5 AT patients further developed SSS during the correction of AT by radiofrequency ablation. Late gadolinium-enhancement cardiovascular magnet resonance showed mild to severely dilated atria, without bilateral ventricular scarring or functional impairment. Serum biomarkers of collagen screening demonstrated significant increased collagen synthesis than collagen degradation in IIF-ACM patients. Cardiomyopathy-related genetic screening depicted no clinically relevant mutation. Histological studies showed global fibrosis of atria (Fig. 1). Conclusions We systemically reported 34 patients with IIF-ACM, which is characterized by atrial scarring and relevant arrhythmias. Ventricular functions of note were preserved in all patients. However, the underlying etiology of IIF-ACM remains to be investigated.

Rainstorm is one of the major natural disasters in the world. Because of the complexity and non-linearity, using the current methods to correctly monitor and predict rainfalls is difficult. In recent years, with the rapid developments of nonlinear science, nonlinear time series analysis has been widely used in many scientific and technological fields. In this study two kinds of nonlinear methods, i.e., the robust symbolic dynamics and information entropy, are used for nonlinear time series analysis of rainstorms. The theoretical bases on symbolic dynamics, information entropy and nonlinear time series analysis are introduced, first. Then, a new algorithm for rainstorm monitoring, including data preprocessing, time series symbolizing, symbolic time series segmentation and information entropy calculations, is described. Finally, 45 cases of heavy rainstorms around the world are analyzed. The preliminary results show that the method developed in this paper is promising for rainstorm monitoring.

Satellite remote sensing of dust aerosol depth is quite significant for practical application. In this paper, airborne dust AOD is retrieved from the hyperspectral observed data of the Atmospheric Infra-Red Sounder (AIRS) by using Singular Value Decomposition (SVD) method which is first proposed by L Kuser in 2011. According to the analysis, 8.8-12 infrared observation can be used for dust aerosol retrieval. This method took advantage of the spectral shape of dust extinction and surface and atmospheric influence over the total 8.8–12μm window band. Though the proper linear combination of the singular vectors, dust signal was finally distinguish from the influence of surface emissivity and gas absorption. Then dust AOD of Beijing areas was retrieved to validate this method. As a result, the inversion by using SVD is good with ground-based observations of Aerosol Observation Network (AERONET) data, where their correlation coefficient is 0.9891. In contrast to the traditional physical methods, this method takes advantage of the statistics without losing the physical meaning.