Effects of radiofrequency catheter ablation for premature ventricular complexes originating from the right ventricular outflow tract on right ventricular function.

INTRODUCTION: This study aimed to elucidate the relationship between premature ventricular complexes (PVCs) and right ventricular (RV) dysfunction, and the effects of radiofrequency catheter ablation (RFCA) on RV function. METHODS: A total of 110 patients (age, 50.8 ± 14.4 years; 30 men) without structural heart disease who had undergone RFCA for RV outflow tract (RVOT) PVCs were retrospectively included. RV function was assessed using fractional area change (FAC) and global longitudinal strain (GLS) before and after RFCA. Clinical data were compared between the RV dysfunction (n = 63) and preserved RV function (n = 47) groups. The relationship between PVC burden and RV function was analyzed. Change in RV function before and after RFCA was compared between patients with successful and failed RFCA. RESULTS: PVC burden was significantly higher in the RV dysfunction group than in the preserved RV function group (p < .001). FAC and GLS were significantly worse in proportion to PVC burden (p < .001 and p < .001, respectively). The risk factor associated with RV dysfunction was PVC burden [odds ratio (95% confidence interval), 1.092 (1.052-1.134); p < .001]. Improvement in FAC (13.0 ± 8.7% and -2.5 ± 5.6%, respectively; p < .001) and GLS (-6.8 ± 5.7% and 2.1 ± 4.2%, respectively; p < .001) was significant in the patients with successful RFCA, compared to the patients in whom RFCA failed. CONCLUSIONS: Frequent RVOT PVCs are associated with RV dysfunction. RV dysfunction is reversible by successful RFCA.

Exploring the Potential of Pulse Transit Time as a Biomarker for Sleep Efficiency through a Comparison Analysis with Heart Rate and Heart Rate Variability.

The relationship between sleep dynamics and blood pressure (BP) changes is well established. Moreover, sleep efficiency and wakefulness during sleep (WASO) events have a significant impact on BP dipping. Despite this knowledge, there is limited research on the measurement of sleep dynamics and continuous blood pressure (CBP). This study aims to explore the relationship between sleep efficiency and cardiovascular function indicators such as pulse transit time (PTT), as a biomarker of CBP, and heart rate variability (HRV), measured using wearable sensors. The results of the study conducted on 20 participants at the UConn Health Sleep Disorders Center suggest a strong linear relationship between sleep efficiency and changes in PTT (r2 = 0.8515) and HRV during sleep (r2 = 5886). The findings of this study contribute to our understanding of the relationship between sleep dynamics, CBP, and cardiovascular health.

Impact of aortic atheroma and distensibility on diastolic function and prognosis in patients with ischemic stroke.

BACKGROUND: Patients with ischemic stroke are vulnerable to heart failure with preserved ejection fraction (HFpEF) because these conditions share common risk factors. Although evaluation of the ascending aorta, aortic arch, and proximal descending thoracic aorta is an essential step to determine the source of the causative embolism, the relationship between the degree of aortic atheroma and left ventricular (LV) diastolic function has not been extensively investigated. METHODS: We analyzed the transesophageal and transthoracic echocardiography in ischemic stroke patients. Patients with previous coronary artery disease, valvular heart disease of more than moderate degree, and an LV ejection fraction of less than 50% were excluded. The relationships between the grade of the aortic atheroma, aortic stiffness indexes, and diastolic functional indexes were evaluated. RESULTS: In 295 patients, the atheroma grade was significantly correlated with aortic stiffness index, ratio of mitral annular and inflow velocities (E/e'), left atrial volume index, and LV diastolic elastance. With further adjustment for age, hypertension, diabetes, estimated glomerular filtration rate, left atrial volume index, and LV mass index, the significance of the atheroma grade was attenuated. In the subgroup analysis, the atheroma grade was significantly and independently related to E/e' in women (ß = 0.181, p = 0.032), but not in men. However, atheroma grade was not associated with poor clinical outcomes in either sex. CONCLUSIONS: Aortic atheroma grade was significantly and independently related to LV diastolic function, especially in women. This suggests that aortic atheroma is an index of arterial stiffness and a potential risk factor for HFpEF through ventricular-vascular interactions, especially in women.

Effects of left atrial function on pulmonary arterial pressure in acute myocardial infarction, hypertrophic and dilated cardiomyopathy.

BACKGROUND: To investigate the differential contribution of the left atrial (LA) function and left ventricular (LV) fibrosis to pulmonary arterial systolic pressure (PASP) in hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and reperfused acute myocardial infarction (AMI). METHODS: Data of 370 patients with HCM (n = 133), DCM (n = 114) and reperfused AMI (n = 123) who underwent both echocardiography and cardiovascular magnetic resonance (CMR) were comprehensively reviewed. Phasic LA volumes, LA-global longitudinal strain (GLS), LA stiffness index, defined as E/e'/LA-GLS and extracellular volume fraction (ECV) of LV were measured using CMR. RESULTS: E/e' was correlated with PASP in all groups; however, the predicted value was significantly attenuated after adjusting for LA volume and LA strain in HCM and DCM, but remained significant in AMI. The LA stiffness index was related to PASP in HCM (p = 0.01) and DCM (p = 0.03) independent of LA volume index and E/e', but not in AMI. In DCM, ECV was significantly related to PASP (p < 0.001) independent of LA volume index and E/e'. When subdivided according to the linear regression between PASP and E/e', patients in the discrepantly high PASP group had lower total emptying fraction and reservoir fraction of left atrium in HCM and DCM but not in AMI. CONCLUSIONS: The LA function in HCM and DCM and LV fibrosis in DCM correlated with PASP independent of E/e' and LA size, contrary to that in AMI. These results suggest the presence of LA dysfunction in non-ischemic cardiomyopathies and usefulness of ECV measurement in DCM for the comprehensive evaluation of LV diastolic function.

Effect of Renal and Left Ventricular Function on Serial Pulmonary Arterial Pressure Changes after Device Closure of Atrial Septal Defect.

BACKGROUND: The age of candidates for device closure of atrial septal defect (ASD) has been increasing. Thus, concerns exist about dyspnea aggravation or atrial fibrillation development after device closure due to augmentation of left ventricular (LV) and left atrial (LA) preload. This study aimed to examine patterns and determinants of serial pulmonary arterial pressure and left ventricular filling pressure changes after device closure of ASD. METHODS: Among the 86 consecutive patients who underwent percutaneous device closure of ASD, those with end-stage renal disease or those without pre- or postprocedural Doppler data were excluded. The clinical, transesophageal, and transthoracic echocardiographic findings of 78 patients were collected at baseline, one-day postprocedure, and one-year follow-up. RESULTS: The mean age of study patients was 49.8 ± 15.0 years, and the average maximal defect diameter and device size were 20.2 ± 6.0 mm and 23.8 ± 6.4 mm. Four patients (5.6%) underwent new-onset atrial fibrillation, and five patients (6.4%) took diuretics within one-year after closure. Some patients (n = 21; 27%) exhibited paradoxically increased tricuspid regurgitant velocity (TRV) one-day postprocedure; they also were older with lower e', glomerular filtration rate, and LV ejection fraction and a higher LA volume index. However, even in these patients, TRV deceased below baseline levels one-year later. Both E/e' and LA volume index significantly increased immediately after device closure, but all decreased one-year later. Larger defect size and higher TRV were significantly correlated with immediate E/e' elevation. CONCLUSION: In older, renal, diastolic, and systolic dysfunctional patients with larger LA and scheduled for larger device implantation, peri-interventional preload reduction therapy would be beneficial.

Long-term prognosis of short QT interval in Korean patients: a multicenter retrospective cohort study.

BACKGROUND: Short QT syndrome is a rare, inherited channelopathy associated with sudden cardiac arrest (SCA) but the characteristics and prognosis of short QT interval (SQTI) in Korean patients remain unclear. This study aimed to determine the clinical characteristics and outcomes of SQTI in a Korean population. METHODS: Consecutive patients with SQTI from January 1999 to March 2019 in three university hospitals in South Korea were recruited. SQTI was defined as a Bazett's formula-corrected QT interval (QTc) ≤ 340 ms in serial electrocardiograms. Age- and sex-matched patients with a normal QTc and without overt cardiovascular disease were included in a 1:4 ratio. Clinical and ECG features and outcomes were compared between patients with and without SQTI. RESULTS: 34 patients with SQTI [age, 23.5 (21-30.5) years; 31 male] were followed up for 4.8 (2.0-7.8) years. Early repolarization, tall T wave, and U wave were significantly more frequent in patients with SQTI than in those without SQTI. QT dispersion [44.0 (28.0-73.0) vs. 20.0 (12.0-35.0) ms, P < 0.001] was significantly wider and heart rate [52.0 (47.0-58.0) vs. 70.0 (62.3-84.0)/min, P < 0.001] was significantly slower in patients with SQTI than in those without. Atrial fibrillation (AF, 11.8% vs. 2.2%, P = 0.030) and ventricular arrhythmia (VA)/SCA (8.7% vs. 0%, P = 0.007) were significantly more frequent in patients with SQTI than in those without. SQTI was significantly associated with AF [odds ratio, 5.911; 95% confidence interval, 1.257-27.808; P = 0.025] and VA/SCA. CONCLUSIONS: In this subset of Korean population, SQTI was associated with AF and VA/SCA.

Subclinical cardiac perforation by cardiac implantable electronic device leads detected by cardiac computed tomography.

BACKGROUND: The relationship between the characteristics of cardiac implantable electronic device (CIED) leads and subclinical cardiac perforations remains unclear. This study aimed to evaluate the incidence of subclinical cardiac perforation among various CIED leads using cardiac computed tomography (CT). METHODS: A total of 271 consecutive patients with 463 CIED leads, who underwent cardiac CT after CIED implantation, were included in this retrospective observational study. Cardiac CT images were reviewed by one radiologist and two cardiologists. Subclinical perforation was defined as traversal of the lead tip past the outer myocardial layer without symptoms and signs related to cardiac perforation. We compared the subclinical cardiac perforation rates of the available lead types. RESULTS: A total of 219, 49, and 3 patients had pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy, respectively. The total subclinical cardiac perforation rate was 5.6%. Subclinical cardiac perforation by screw-in ventricular leads was significantly more frequent than that caused by tined ventricular leads (13.3% vs 3.3%, respectively, p = 0.002). There were no significant differences in the incidence of cardiac perforation between atrial and ventricular leads, screw-in and tined atrial leads, pacing and defibrillator ventricular leads, nor between magnetic resonance (MR)-conditional and MR-unsafe screw-in ventricular leads. Screw-in ventricular leads were significantly associated with subclinical cardiac perforation [odds ratio, 4.554; 95% confidence interval, 1.587-13.065, p = 0.005]. There was no case subclinical cardiac perforation by septal ventricular leads. CONCLUSIONS: Subclinical cardiac perforation by screw-in ventricular leads is not rare. Septal pacing may be helpful in avoiding cardiac perforation.

Usefulness of cardiac magnetic resonance images for prediction of sudden cardiac arrest in patients with mitral valve prolapse: a multicenter retrospective cohort study.

BACKGROUND: An association has been identified between mitral valve prolapse (MVP) and sudden cardiac arrest (SCA), and ventricular arrhythmias (VA). This study aimed to elucidate predictive factors for SCA or VA in MVP patients. METHODS: MVP patients who underwent cardiac magnetic resonance (CMR) were retrospectively included. Patients with other structural heart disease or causes of aborted SCA were excluded. Clinical characteristics (sex, age, body mass index, histories of diabetes, hypertension, and dyslipidemia) and electrocardiographic (PR interval, QRS duration, corrected QT interval, inverted T wave in the inferior leads, bundle branch block, and atrial fibrillation), echocardiographic [mitral regurgitation grade, prolapsing mitral leaflet, and right ventricular systolic pressure (RVSP)], and CMR [left atrial volume index, both ventricular ejection fractions, both ventricular end-diastolic and systolic volume indexes, prolapse distance, mitral annular disjunction, systolic curling motion, presence of late gadolinium enhancement (LGE), LGE volume and proportion] parameters were analyzed. RESULTS: Of the 85 patients [age, 54.0 (41.0-65.0) years; 46 men], seven experienced SCA or VA. Younger age and wide QRS complex were observed more often in the SCA/VA group than in the no-SCA/VA group. The SCA/VA group exhibited lower RVSP, more systolic curling motion and LGE, greater LGE volume, and higher LGE proportion. The presence of LGE [hazard ratio (HR), 19.8; 95% confidence interval (CI) 2.65-148.15; P = 0.004], LGE volume (HR 1.08; 95% CI 1.02-1.14; P = 0.006) and LGE proportion (HR 1.32; 95% CI 1.08-1.60; P = 0.006) were independently associated with higher risk of SCA or VA in MVP patients together with systolic curling motion in each model. CONCLUSIONS: The presence of systolic curling motion, high LGE volume and proportion, and the presence of LGE on CMR were independent predictive factors for SCA or VA in MVP patients.

Contribution of sarcomere gene mutations to left atrial function in patients with hypertrophic cardiomyopathy.

BACKGROUND: Left atrial (LA) enlargement and dysfunction are related to clinical course in patients with hypertrophic cardiomyopathy (HCM). We aimed to investigate genetic contribution to LA structural and functional remodeling. METHODS: Two hundred twelve patients were consecutively enrolled, and echocardiography and extensive genetic analysis were performed. Cardiac magnetic resonance (CMR) was performed in 135 patients. Echocardiography was also performed in controls (n = 30). RESULTS: Patients with HCM had lower late-diastolic mitral annular velocity (a') and higher LA volume index (LAVI) than controls. Patients with pathogenic or likely pathogenic sarcomere gene mutations (PSM, n = 67, 32%) had higher LAVI and lower CMR-derived LA total emptying fraction (37.0 ± 18.5 vs. 44.2 ± 12.4%, p = 0.025). In patients without AF (n = 187), the PSM had lower a' (6.9 ± 2.0 vs. 7.8 ± 1.9 cm/s, p = 0.004) than others. The PSM had higher prevalence and amount of late gadolinium enhancement (LGE) in the left ventricle (LV). In multivariate analysis, PSM was significantly related to lower a' independent of E/e', LV mass index, and LAVI. However, the relation significantly attenuated after adjustment for the extent of LGE in the LV, suggesting common myopathy in the LV and LA. In addition, PSM was significantly related to lower LA total emptying fraction independent of age, E/e', s', LV ejection fraction, LV myocardial global longitudinal strain and %LGE mass. CONCLUSIONS: PSM was related to LA dysfunction independent of LV filling pressure and LAVI, suggesting its contribution to atrial myopathy in HCM.

Biodegradable Piezoelectric Force Sensor.

Measuring vital physiological pressures is important for monitoring health status, preventing the buildup of dangerous internal forces in impaired organs, and enabling novel approaches of using mechanical stimulation for tissue regeneration. Pressure sensors are often required to be implanted and directly integrated with native soft biological systems. Therefore, the devices should be flexible and at the same time biodegradable to avoid invasive removal surgery that can damage directly interfaced tissues. Despite recent achievements in degradable electronic devices, there is still a tremendous need to develop a force sensor which only relies on safe medical materials and requires no complex fabrication process to provide accurate information on important biophysiological forces. Here, we present a strategy for material processing, electromechanical analysis, device fabrication, and assessment of a piezoelectric Poly-l-lactide (PLLA) polymer to create a biodegradable, biocompatible piezoelectric force sensor, which only employs medical materials used commonly in Food and Drug Administration-approved implants, for the monitoring of biological forces. We show the sensor can precisely measure pressures in a wide range of 0-18 kPa and sustain a reliable performance for a period of 4 d in an aqueous environment. We also demonstrate this PLLA piezoelectric sensor can be implanted inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction. This piezoelectric sensor offers an appealing alternative to present biodegradable electronic devices for the monitoring of intraorgan pressures. The sensor can be integrated with tissues and organs, forming self-sensing bionic systems to enable many exciting applications in regenerative medicine, drug delivery, and medical devices.

Prospective, Randomized, Comparative, Multicenter Study of the Hybrid Ultrasonic Advanced Bipolar Device and the Ultrasonic Coagulating Shears in Open Thyroidectomy.

Background. The hybrid ultrasonic advanced bipolar device (HUB) that integrates ultrasonic energy and advanced bipolar energy was recently developed and applied to thyroid surgery. The purpose of this study was to compare the efficacy and safety of HUB and ultrasonic coagulating shears for open thyroidectomy. Methods. A total of 200 patients were enrolled from April to September 2017 in this prospective, randomized, multicenter study. Patients were randomly assigned to an ultrasonic group (n = 101) or a hybrid group (n = 99). Results. Operation times were similar in the 2 study groups, that is, 54.2 ± 25.2 minutes in the ultrasonic group and 50.2 ± 21.6 minutes in the hybrid group. Postoperative surgical results and morbidities were no different in the 2 groups. However, the total amount of bleeding was significantly less in the hybrid group (13.0 ± 17.7 mg vs 8.6 ± 11.5 mg; P = .042). Conclusions. Our study showed that there was no significant difference between the 2 groups in postoperative surgical results and morbidity. The total bleeding amount was significantly less in the hybrid group. The study shows that HUB is comparable to the ultrasonic coagulating shears in terms of efficacy and safety during thyroid surgery.

Persistent atrial fibrillation over 3 years is associated with higher recurrence after catheter ablation.

INSTRUCTION: Longer atrial fibrillation (AF) durations have higher recurrence rates after rhythm control. However, there is limited data on the effect of the AF duration on recurrence after atrial fibrillation catheter ablation (AFCA). In the present study, we investigated the rhythm outcome of AFCA according to the AF duration based on the first electrocardiogram (ECG) diagnosis. METHODS AND RESULTS: We included 1005 patients with AF (75% male, 59 ± 11 years old) who underwent AFCA and whose first ECG diagnosis time point was evident. The clinical characteristics and rhythm outcomes were compared based on the AF duration (≤3 years, n = 537; >3 years, n = 468) and AF burden (paroxysmal atrial fibrillation [PAF], n = 387; persistent atrial fibrillation [PeAF], n = 618). Longer AF durations were associated with older age (P = .020), larger left atrial size (P = .009) and a higher number of patients with hypertension (P < .001) or PeAF (P < .001). During 24 ± 22 months of follow-up, the postablation clinical recurrence rate was higher in patients with a longer AF duration (logrank P = .002). The AF recurrence rate was significantly higher in PeAF patients with an AF duration >3 years (logrank P = 0.009), but not in subjects with PAF (logrank P = .939). In a multivariate Cox regression analysis, a longer AF duration was significantly associated with a higher clinical recurrence rate after AFCA in PeAF patients (adjusted hazard ratio, 1.06; range, 1.03-0.10; P = 0.001), but not PAF. CONCLUSION: Although longer AF duration was associated with higher clinical recurrence rates after AFCA, the rate was significant in patients with PeAF lasting >3 years, but not in PAF patients.

Preparation and characterization of positively surface charged zinc oxide nanoparticles against bacterial pathogens.

Solvothermal synthesis was used to investigate the formation of zinc oxide (ZnO) nanoparticles (NPs). A series of ZnO NPs was synthesized with different relative ratios of didodecyldimethylammonium bromide (DDAB) and zinc nitrate (ZN). The variation in the molarity influenced the crystallinity, size, and morphology of the obtained ZnO NPs. X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and zeta potential analysis were used to study the characteristic features of the ZnO NPs. The ZnO surface charge, size, and morphological structure were highly reliant on the concentrations of DDAB and ZN. With increasing relative ratio of DDAB to ZN, the particle size of ZnO NPs decreased and the surface charge increased to higher positive value. The ZnO NPs synthesized with cationic liquid DDAB presented enhanced performance in preventing the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains. The antibacterial activity of ZnO NPs have direct contact with the microbial cell wall resulting in destruction of bacterial cell integrity, release of antimicrobial Zn2+ ions, and induce cell death. This is due to the positively charged smaller ZnO NPs, prepared with DDAB cationic surfactant, effectively acting as an antimicrobial agent against food-borne pathogenic bacteria.

Optimal Duration for Dual Antiplatelet Therapy After Left Main Coronary Artery Stenting.

BACKGROUND: Coronary interventions using drug-eluting stents (DESs) of left main coronary artery (LMCA) lesions have shown favorable clinical outcomes. However, duration of dual antiplatelet therapy (DAPT) after LMCA interventions has not yet been investigated.Methods and Results:From a multicenter Korean Multicenter Angioplasty Team (KOMATE) registry, 1,004 patients who received DES implantations for LMCA lesions and did not experience major adverse cardiovascular events (including major bleeding) for 1 year after coronary intervention were analyzed. Patients were divided into 2 groups; DAPT ≤12 (n=503) and >12 months (n=501). The primary endpoint was number of net clinical adverse events (NACEs), composite of cardiac deaths, myocardial infarctions, stent thrombosis and major bleeding events. During a 4.5-year follow-up period after LMCA interventions, the DAPT >12 months group showed a lower NACE rate than the DAPT ≤12 months group (adjusted-HR 0.53 [0.29-0.99], P=0.045). For patients who maintained DAPT >12 months, rate of cardiac deaths, myocardial infarctions, and stent thrombosis events were lower than in patients who had DAPT ≤12 months (adjusted-HR 0.35 [0.17-0.73], P=0.005) without increased major bleeding (P=0.402). CONCLUSIONS: For patients who can continue DAPT without major bleeding events, prolonged DAPT (>12 months) after LMCA stenting demonstrated better long-term efficacy outcomes than DAPT ≤12 months with comparable safety.

Challenges in Design and Fabrication of Flexible/Stretchable Carbon- and Textile-Based Wearable Sensors for Health Monitoring: A Critical Review.

To demonstrate the wearable flexible/stretchable health-monitoring sensor, it is necessary to develop advanced functional materials and fabrication technologies. Among the various developed materials and fabrication processes for wearable sensors, carbon-based materials and textile-based configurations are considered as promising approaches due to their outstanding characteristics such as high conductivity, lightweight, high mechanical properties, wearability, and biocompatibility. Despite these advantages, in order to realize practical wearable applications, electrical and mechanical performances such as sensitivity, stability, and long-term use are still not satisfied. Accordingly, in this review, we describe recent advances in process technologies to fabricate advanced carbon-based materials and textile-based sensors, followed by their applications such as human activity and electrophysiological sensors. Furthermore, we discuss the remaining challenges for both carbon- and textile-based wearable sensors and then suggest effective strategies to realize the wearable sensors in health monitoring.

Metagenomic analysis of relationships between the denitrification process and carbon metabolism in a bioaugmented full-scale tannery wastewater treatment plant.

The goal of this study was to investigate the relationship between the denitrification process and carbon metabolism in a full-scale tannery wastewater treatment plant bioaugmented with the microbial consortium BM-S-1. The metagenomic analysis of the microbial community showed that Brachymonas denitrificans, a known denitrifier, was present at a high level in the treatment stages of buffering (B), primary aeration (PA), and sludge digestion (SD). The occurrences of the amino acid-degrading enzymes alpha ketoglutarate dehydrogenase (α-KGDH) and tryptophan synthase were highly correlated with the presence of denitrification genes, such as napA, narG, nosZ and norB. The occurrence of glutamate dehydrogenase (GDH) was also highly paralleled with the occurrence of denitrification genes such as napA, narG, and norZ. The denitrification genes (nosZ, narG, napA, norB and nrfA) and amino acid degradation enzymes (tryptophan synthase, α-KGDH and pyridoxal phosphate dependent enzymes) were observed at high levels in B. This indicates that degradation of amino acids and denitrification of nitrate may potentially occur in B. The high concentrations of the fatty acid degradation enzyme groups (enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase and ß-ketothiolase) were observed together with the denitrification genes, such as napA, narG and nosZ. Phospholipase/carboxylesterase, enoyl-CoA hydratase/isomerase, acyl-CoA dehydrogenase, phenylacetate degradation enzyme and 3-hydroxyacyl-CoA dehydrogenase 2 were also dominant in B. All these results clearly indicate that the denitrification pathways are potentially linked to the degradation pathways of amino acids and fatty acids whose degradation products go through the TCA cycle, generating the NADH that is used as electron donors for denitrification.

Environmental Exposure to Arsenic, Lead, and Cadmium in People Living near Janghang Copper Smelter in Korea.

Concentrations of heavy metals exceed safety thresholds in the soil near Janghang Copper Refinery, a smelter in Korea that operated from 1936 to 1989. This study was conducted to evaluate the level of exposure to toxic metals and the potential effect on health in people living near the smelter. The study included 572 adults living within 4 km of the smelter and compared them with 413 controls group of people living similar lifestyles in a rural area approximately 15 km from the smelter. Urinary arsenic (As) level did not decrease according to the distance from the smelter, regardless of gender and working history in smelters and mines. However, in subjects who had no occupational exposure to toxic metals, blood lead (Pb) and cadmium (Cd) and urinary Cd decreased according to the distance from the smelter, both in men and women. Additionally, the distance from the smelter was a determinant factor for a decrease of As, Pb, and Cd in multiple regression models, respectively. On the other hands, urinary Cd was a risk factor for renal tubular dysfunction in populations living near the smelter. These results suggest that Janghang copper smelter was a main contamination source of As, Pb, and Cd, and populations living near the smelter suffered some adverse health effects as a consequence. The local population should be advised to make efforts to reduce exposure to environmental contaminants, in order to minimize potential health effects, and to pay close attention to any health problems possibly related to toxic metal exposure.

Energy Calibration of a CdTe Photon Counting Spectral Detector with Consideration of its Non-Convergent Behavior.

Fast and accurate energy calibration of photon counting spectral detectors (PCSDs) is essential for their biomedical applications to identify and characterize bio-components or contrast agents in tissues. Using the x-ray tube voltage as a reference for energy calibration is known to be an efficient method, but there has been no consideration in the energy calibration of non-convergent behavior of PCSDs. We observed that a single pixel mode (SPM) CdTe PCSD based on Medipix-2 shows some non-convergent behaviors in turning off the detector elements when a high enough threshold is applied to the comparator that produces a binary photon count pulse. More specifically, the detector elements are supposed to stop producing photon count pulses once the threshold reaches a point of the highest photon energy determined by the tube voltage. However, as the x-ray exposure time increases, the threshold giving 50% of off pixels also increases without converging to a point. We established a method to take account of the non-convergent behavior in the energy calibration. With the threshold-to-photon energy mapping function established by the proposed method, we could better identify iodine component in a phantom consisting of iodine and other components.

Metagenomic insight of nitrogen metabolism in a tannery wastewater treatment plant bioaugmented with the microbial consortium BM-S-1.

Nitrogen (N) removal in a tannery wastewater treatment plant was significantly enhanced by the bioaugmentation of the novel consortium BM-S-1. In order to identify dominant taxa responsible for N metabolisms in the different stages of the treatment process, Illumina MiSeq Sequencer was used to conduct metagenome sequencing of the microbial communities in the different stages of treatment system, including influent (I), buffering (B), primary aeration (PA), secondary aeration (SA) and sludge digestion (SD). Based on MG-RAST analysis, the dominant phyla were Proteobacteria, Bacteroidetes and Firmicutes in B, PA, SA and SD, whereas Firmicutes was the most dominant in I before augmentation. The augmentation increased the abundance of the denitrification genes found in the genera such as Ralstonia (nirS, norB and nosZ), Pseudomonas (narG, nirS and norB) and Escherichia (narG) in B and PA. In addition, Bacteroides, Geobacter, Porphyromonasand Wolinella carrying nrfA gene encoding dissimilatory nitrate reduction to ammonium were abundantly present in B and PA. This was corroborated with the higher total N removal in these two stages. Thus, metagenomic analysis was able to identify the dominant taxa responsible for dissimilatory N metabolisms in the tannery wastewater treatment system undergoing bioaugmentation. This metagenomic insight into the nitrogen metabolism will contribute to a successful monitoring and operation of the eco-friendly tannery wastewater treatment system.

The ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em) predicts improvement in left ventricular systolic and diastolic function 1 year after catheter ablation for atrial fibrillation.

AIMS: Successful rhythm control after atrial fibrillation catheter ablation is known to induce left atrial reverse remodelling and improve left ventricular (LV) function. We explored the clinical factors affecting LV systolic and diastolic function 1-year after catheter ablation for atrial fibrillation. METHODS AND RESULTS: We compared pre-procedural and 1-year follow-up echocardiograms in 521 patients with atrial fibrillation who underwent catheter ablation. Left ventricular systolic function was estimated by the ejection fraction (EF); diastolic function was estimated by the ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em). (i) Catheter ablation of atrial fibrillation significantly reduced left atrium volume index (P < 0.001) and improved LV EF both in patients with recurrent atrial fibrillation (n = 133, P = 0.008) and those without recurrence (n = 388, P < 0.001). (ii) Follow-up EF was significantly improved in patients with baseline E/Em < 15 (n = 454, P < 0.001), whereas E/Em was significantly reduced in patients with pre-procedural E/Em ≥ 15 (n = 67, P = 0.008). (iii) Baseline E/Em < 15 (ß = -3.854, 95% CI -5.99 to -1.72, P < 0.001), baseline EF <50% (ß = 10.586, 95% CI 7.55 to 13.63, P < 0.001), and female (ß = -1.726, 95% CI -3.36 to -0.10, P = 0.038) were independently associated with improved EF. Baseline E/Em ≥ 15 (ß = 4.896, 95% CI 3.45 to 6.34, P < 0.001) and younger age (ß = -0.066, 95% CI -0.11 to -0.02, P = 0.003) were independent factors associated with improved E/Em. CONCLUSION: Pre-procedural E/Em predicted improvement in LV systolic and diastolic functions 1 year after catheter ablation for atrial fibrillation. Low baseline E/Em was independently associated with improved EF, while high E/Em predicted improvement in LV diastolic function.