Development and Validation of a Nomogram of Persistent Pulmonary Hypertension in Adult Pretricuspid Shunts After Correction.

BACKGROUND: Pretricuspid shunts have been associated with poorer survival rates in patients with Eisenmenger syndrome compared with postricuspid shunts and complex lesions. However, the risk stratification for persistent pulmonary hypertension (PH) in this population remains uncertain. METHODS AND RESULTS: We retrospectively enrolled 103 patients with pretricuspid shunts with high total pulmonary resistance >4.5 Wood units (estimated pulmonary vascular resistance ≥3 Wood units). During a mean±SD follow-up of 20.95±24.84 months, 32 patients developed postoperative persistent PH after shunt correction. We identified 3 significant predictors of postoperative persistent PH, including mean pulmonary artery pressure after inhaled oxygen ≥40.5 mm Hg (odds ratio [OR], 7.78 [95% CI, 2.02-30.03]; P<0.01), total pulmonary resistance after inhaled oxygen ≥6.5 Wood units (estimated pulmonary vascular resistance ≥5 Wood units; OR, 12.23 [95% CI, 2.12-70.46]; P<0.01), and artery oxygen saturation at rest <95% (OR, 3.34 [95% CI, 1.07-10.44]; P=0.04). We established the prediction model with the C-statistics of 0.85 (95% CI, 0.77-0.93; P<0.01), and the C-statistic was 0.83 (95% CI, 0.80-0.86) after bootstrapping 10 000 times with a good performance of the nomogram calibration curve for predicting persistent PH. CONCLUSIONS: Our study presents a multivariable risk stratification model for persistent PH after shunt correction in adults with pretricuspid shunts. This model, based on 3 hemodynamic predictors after inhaled oxygen, may assist in identifying individuals at higher risk of persistent PH after shunt correction.

Left ventricular hypertrophy phenotype to predict incident atrial fibrillation: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIM: Left ventricular hypertrophy (LVH) has been shown to be associated with the occurrence of atrial fibrillation (AF). However, the predictive value of the LVH phenotype for incident AF remains uncertain. This study aimed to investigate the predictive value of LVH phenotype for incident AF. METHODS AND RESULTS: This study utilized the Multi-Ethnic Study of Atherosclerosis (MESA) data. LVH was defined by cardiac magnetic resonance measured LV mass index. Isolated LVH was determined as LVH without elevated cardiac biomarker and malignant LVH was determined as LVH with at least 1 elevated biomarker. Receiver-operating characteristic (ROC) analysis was performed to calculate areas under the curves (AUC) for predicting AF. A total of 4983 community-dwelling participants were included, with a mean age of 61.5 years. 279 (5.6 %) had isolated LVH, and 222 (4.5 %) had malignant LVH. During a median follow-up of 8.5 years, 272 incident AF was observed. Compared to participants without LVH and elevated cardiac biomarkers, those with isolated LVH (HR, 1.82; 95 % CI, 1.03-3.20) and malignant LVH (HR, 4.13; 95 % CI, 2.77-6.16) had a higher risk of incident AF. Malignant LVH carried a 1.5-fold increased risk of AF compared to isolated LVH (HR: 2.48, 95 % CI: 1.30-4.73). Including the LVH phenotype in the CHARGE-AF model improved model discrimination (AUC increase: 0.03, p < 0.001). CONCLUSIONS: The risks of AF incidence varied across LVH phenotypes. Malignant LVH carried the highest risk among LVH phenotypes. LVH phenotype provides incremental predictive value over the variables included in the CHARGE-AF model.

Surgical Outcome of Proximal Isolated Subclavian Artery Aneurysms: A Single-Center Retrospective Observational Study.

OBJECTIVE: The objective of this study was to introduce our institutional experience of treatment strategies (cervical subclavian artery reconstruction, thoracotomy subclavian artery reconstruction and endovascular treatment) for proximal isolated subclavian artery aneurysms (PISAAs). METHODS: we retrospectively analyzed 15 consecutive patients with PISAAs treated by different treatment strategies (cervical reconstruction, thoracotomy reconstruction and endovascular treatment) in our institution from May 2016 to May 2022. Baseline data, surgery-related data, postoperative information and long-term follow-up were assessed. RESULTS: A total of 17 PISAAs in 15 consecutive patients were treated in our institution. The success rates of subclavian artery reconstruction in the cervical reconstruction, the thoracotomy reconstruction and the endovascular treatment were 100%, 100 and 83.33%, respectively. About the involved vertebral artery, the reconstruction rates in the cervical reconstruction, the thoracotomy reconstruction, and the endovascular treatment were 80%, 75%, and 0, respectively. The intraoperative blood loss in the thoracotomy reconstruction was significantly higher than that in the cervical reconstruction and the endovascular treatment (p<0.05). The total operation time of the thoracotomy reconstruction was significantly longer than that of the cervical reconstruction and the endovascular treatment (p<0.05). In terms of postoperative ventilator use time, total postoperative drainage fluid, total postoperative drainage time, and ICU duration, both the thoracotomy reconstruction and the cervical reconstruction were significantly more than the endovascular treatment (p<0.05). During the follow-up, one patient in the endovascular treatment underwent re-intervention 22 months after surgery due to in-stent occlusion. CONCLUSIONS: For patients with PISAAs, different treatment strategies are recommended depending on the size of the aneurysms and whether the involved vertebral arteries require reconstruction. CLINICAL IMPACT: This article is the largest study on the treatment strategies of PISAAs. By comparing the prognosis and complications of endovascular treatment with those of open surgery, it provides a certain reference basis for the choice of treatment for patients with PISAAs. For patients with aneurysms' diameter of >50 mm, the thoracotomy subclavian artery reconstruction is recommended; for patients with aneurysms' diameter of <30 mm requiring reconstruction of the involved vertebral arteries, the cervical subclavian artery reconstruction is recommended; for patients with aneurysms' diameter of <30 mm not requiring reconstruction of the involved vertebral arteries, the endovascular treatment is recommended.

Space Station-like Composite Nanoparticles for Co-Delivery of Multiple Natural Compounds from Chinese Medicine and Hydrogen in Combating Sensorineural Hearing Loss.

Ototoxic drugs such as aminoglycoside antibiotics and cisplatin (CDDP) can cause sensorineural hearing loss (SNHL), which is closely related to oxidative stress and the acidification of the inner ear microenvironment. Effective treatment of SNHL often requires multifaceted approach due to the complex pathology, and drug combination therapy is expected to be at the forefront of modern hearing loss treatment. Here, space-station-like composite nanoparticles (CCC@mPP NPs) with pH/oxidation dual responsiveness and multidrug simultaneous delivery capability were constructed and then loaded with various drugs including panax notoginseng saponins (PNS), tanshinone IIA (TSIIA), and ammonia borane (AB) to provide robust protection against SNHL. Molecular dynamics simulation revealed that carboxymethyl chitosan/calcium carbonate-chitosan (CCC) NPs and monomethoxy poly(ethylene glycol)-PLGA (mPP) NPs can rendezvous and dock primarily by hydrogen bonding, and electrostatic forces may be involved. Moreover, CCC@mPP NPs crossed the round window membrane (RWM) and entered the inner ear through endocytosis and paracellular pathway. The docking state was basically maintained during this process, which created favorable conditions for multidrug delivery. This nanosystem was highly sensitive to pH and reactive oxygen species (ROS) changes, as evidenced by the restricted release of payload at alkaline condition (pH 7.4) without ROS, while significantly promoting the release in acidic condition (pH 5.0 and 6.0) with ROS. TSIIA/PNS/AB-loaded CCC@mPP NPs almost completely preserved the hair cells and remained the hearing threshold shift within normal limits in aminoglycoside- or CDDP-treated guinea pigs. Further experiments demonstrated that the protective mechanisms of TSIIA/PNS/AB-loaded CCC@mPP NPs involved direct and indirect scavenging of excessive ROS, and reduced release of pro-inflammatory cytokines. Both in vitro and in vivo experiments showed the high biocompatibility of the composite NPs, even after long-term administration. Collectively, this work suggests that composite NPs is an ideal multi-drug-delivery vehicle and open new avenues for inner ear disease therapies.

A prestin-targeting peptide-guided drug delivery system rearranging concentration gradient in the inner ear: An improved strategy against hearing loss.

Hearing loss is mainly due to outer hair cell (OHC) damage in three cochlear turns. Local administration via the round window membrane (RWM) has considerable otological clinical potential in bypassing the blood-labyrinth barrier. However, insufficient drug distribution in the apical and middle cochlear turns results in unsatisfactory efficacy. We functionalized poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) with targeting peptide A665, which specifically bound to prestin, a protein uniquely expressed in OHCs. The modification facilitated the cellular uptake and RWM permeability of NPs. Notably, the guide of A665 towards OHCs enabled more NPs perfusion in the apical and middle cochlear turns without decreasing accumulation in the basal cochlear turn. Subsequently, curcumin (CUR), an appealing anti-ototoxic drug, was encapsulated in NPs. In aminoglycoside-treated guinea pigs with the worst hearing level, CUR/A665-PLGA NPs, with superior performance to CUR/PLGA NPs, almost completely preserved the OHCs in three cochlear turns. The lack of increased low-frequencies hearing thresholds further confirmed that the delivery system with prestin affinity mediated cochlear distribution rearrangement. Good inner ear biocompatibility and little or no embryonic zebrafish toxicity were observed throughout the treatment. Overall, A665-PLGA NPs act as desirable tools with sufficient inner ear delivery for improved efficacy against severe hearing loss.

Interventional Occlusion of Large Patent Ductus Arteriosus in Adults with Severe Pulmonary Hypertension.

(1) Background: the indications for transcatheter closure of large patent ductus arteriosus (PDA) with severe pulmonary hypertension (PH) are still unclear, and scholars have not fully elucidated the factors that affect PH prognosis. (2) Methods: we retrospectively enrolled 134 consecutive patients with a PDA diameter ≥10 mm or a ratio of PDA and aortic >0.5. We collected clinical data to explore the factors affecting follow-up PH. (3) Results: 134 patients (mean age 35.04 ± 10.23 years; 98 women) successfully underwent a transcatheter closure, and all patients had a mean pulmonary artery pressure (mPAP) >50 mmHg. Five procedures were deemed to have failed because their mPAP did not decrease, and the patients experienced uncomfortable symptoms after the trial occlusion. The average occluder (pulmonary end) size was almost twice the PDA diameter (22.33 ± 4.81 mm vs. 11.69 ± 2.18 mm). Left ventricular end-diastolic dimension (LVEDD), mPAP, and left ventricular ejection fraction (LVEF) significantly reduced after the occlusion, and LVEF recovered during the follow-up period. In total, 42 of the 78 patients with total pulmonary resistance >4 Wood Units experienced clinical outcomes, and all of them had PH in the follow-up, while 10 of them had heart failure, and 4 were hospitalized again because of PH. The results of a logistic regression analysis revealed that the postoperative mPAP had an independent risk factor (odds ratio = 1.069, 95% confidence interval: 1.003 to 1.140, p = 0.040) with a receiver operating characteristic curve cut-off value of 35.5 mmHg (p < 0.001). (4) Conclusions: performing a transcatheter closure of large patent ductus arteriosus is feasible, and postoperative mPAP was a risk factor that affected the follow-up PH. Patients with a postoperative mPAP >35.5 mmHg should be considered for targeted medical therapy or should undergo right heart catheterization again after the occlusion.

Is Revascularization of V1 Segment of Vertebral Artery Combined with Ipsilateral Carotid Endarterectomy Safe?

BACKGROUND: The recommendation of the European Society for Vascular Surgery (ESVS) is that vertebral revascularization combined with ipsilateral CEA (carotid endarterectomy) should not be performed in the same operation. ESVS believes that vertebral revascularization combined with ipsilateral CEA increases perioperative death/stroke rates. In our opinion, revascularization of the first segment of vertebral artery (V1) combined with ipsilateral CEA is safe compared to vertebral V1 revascularization in the perioperative period. The purpose of this study is to prove that revascularization of V1 segment of vertebral artery combined with ipsilateral CEA is secure in the perioperative period. METHODS: We describe our experience with homochronous revascularization of V1 segment of vertebral artery with ipsilateral CEA (group B) and simple revascularization of V1 segment of vertebral artery (group A) in 48 consecutive patients during a 5-year period. O.Y. (Ouyang) incisions were used in both groups. We compare the results of the 2 procedures with aspects of mortality, stroke, morbidity, incident rates of complications, and so on. RESULTS: There was no significant difference between patients in group A and group B in terms of red blood cell reduction, postoperative ventilator using time, postoperative drainage volume, postoperative drainage days, postoperative hospitalize duration, and incident rates of postoperative complications. The postoperative complications include death, stroke, Horner syndrome, vocal paralysis, hypoglossal nerve paralysis, wound hematomas, and lymphatic leakage. CONCLUSIONS: Revascularization of vertebral artery combined with ipsilateral CEA should be divided into revascularization of V1 segment of vertebral artery combined with ipsilateral CEA and revascularization of V3 segment of vertebral artery with ipsilateral CEA. Revascularization of V1 segment of vertebral artery combined with ipsilateral CEA is safe; it can be performed for suitable patients who are fit for indications. O.Y. incisions can fully expose the target blood vessels and simplify the procedures without transecting the sternocleidomastoid muscles in operations.

Factors associated with in-hospital mortality from free wall rupture after acute myocardial infarction.

BACKGROUND: Free wall rupture is a fatal and emergency complication of acute myocardial infarction. The factors associated with in-hospital mortality from free wall rupture remain unclear. OBJECTIVES: To investigate the factors associated with in-hospital mortality from free wall rupture. METHODS: We performed a single-center, retrospective study. We enrolled 111 consecutive patients with free wall rupture following acute myocardial infarction who were admitted to Fuwai Hospital from January 2005 to May 2021. The primary endpoint was in-hospital death. Clinical characteristics, laboratory data, and treatment modalities associated with in-hospital mortality were analyzed. RESULTS: Eighty-seven of the 111 study participants died in hospital. Multivariate Cox regression analysis showed that pericardiocentesis (hazard ratio [HR] 0.296, 95% confidence interval [CI] 0.094-0.929, p = 0.037), pericardial effusion at admission (HR 0.083, 95% CI 0.025-0.269, p<0.001), time interval between acute myocardial infarction and free wall rupture (HR 0.670, 95% CI 0.598-0.753, p<0.001), and previous myocardial infarction (HR 0.046, 95% CI 0.010-0.208, p<0.001) were independently associated with in-hospital mortality. CONCLUSIONS: Pericardiocentesis, pericardial effusion at admission, the acute myocardial infarction to free wall rupture time, and previous myocardial infarction are associated with a lower rate of in-hospital mortality from free wall rupture after acute myocardial infarction.

Apparent mineralocorticoid excess: comprehensive overview of molecular genetics.

Apparent mineralocorticoid excess is an autosomal recessive form of monogenic disease characterized by juvenile resistant low-renin hypertension, marked hypokalemic alkalosis, low aldosterone levels, and high ratios of cortisol to cortisone metabolites. It is caused by defects in the HSD11B2 gene, encoding the enzyme 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2), which is primarily involved in the peripheral conversion of cortisol to cortisone. To date, over 50 deleterious HSD11B2 mutations have been identified worldwide. Multiple molecular mechanisms function in the lowering of 11ß-HSD2 activity, including damaging protein stability, lowered affinity for the substrate and cofactor, and disrupting the dimer interface. Genetic polymorphism, environmental factors as well as epigenetic modifications may also offer an implicit explanation for the molecular pathogenesis of AME. A precise diagnosis depends on genetic testing, which allows for early and specific management to avoid the morbidity and mortality from target organ damage. In this review, we provide insights into the molecular genetics of classic and non-classic apparent mineralocorticoid excess and aim to offer a comprehensive overview of this monogenic disease.

Transcatheter closure of inferior sinus venosus defect using a patent ductus arteriosus occluder following simulation with a 3D-printed model.

Background: Transcatheter closure of inferior sinus venosus defect (ISVD) is still contraindication. To explore whether transcatheter closure with patent ductus arteriosus (PDA) occluders is possible for ISVD. Methods: From June 2014 to March 2021, 12 patients were recruited diagnosed as <25 mm ISVD. The three-dimensional printing (3DP) heart model was produced based on multi-slice computed tomography (MSCT) scans. Preoperative closure simulation was planned on the personalized 3D model for each patient. Follow-up including electrocardiography (ECG), transthoracic echocardiography (TTE), and X-ray was traced. Results: 3DP models of 12 patients were successfully printed. Twelve patients had been diagnosed with <25 mm ISVD and 4 of them had another secundum atrial septal defect (ASD). All patients were produced interventional therapy successfully. PDA occluder was implanted to closed ISVD, and ASD was closed using ASD occluder simultaneously. The average diameter of ISVD measured by TTE was (12.67±3.80), and the average diameter of sagittal axes and longitudinal axes measured by the 3D-printed model was (17.08±3.20) and (18.42±4.62) mm, respectively. The average size of PDA (diameter of pulmonary artery side) was (28.17±3.35) mm. Compared with the preoperative, the X-ray cardiothoracic ratio (0.51±0.04 vs. 0.47±0.06, P=0.007) and the right ventricle anterior-posterior diameter (31.17±5.65 vs. 24.58±3.75 mm, P<0.001) of postoperative was significantly decreased. During the average (47.75±27.52) months follow-up, it has achieved satisfying results, and there were no severe adverse events such as device transposition, death, and pericardial tamponade occurred. Conclusions: Assisting by 3D heart model, transcatheter closure of ISVD with PDA occluder had an excellent outcome. This method provides a new considerable treatment strategy for ISVD.

A Novel Frame-Shift Mutation in SCNN1B Identified in a Chinese Family Characterized by Early-Onset Hypertension.

Background: Liddle syndrome is a form of monogenic hypertension caused by mutations in the three homologous subunits of the epithelial sodium channels (ENaCs), α, ß, and γ. It is characterized by early-onset refractory hypertension, hypokalemia, low renin activity, and hypoaldosteronism. In this study, we report a novel frame-shift mutation in SCNN1B responsible for Liddle syndrome in a Chinese family. Methods: DNA samples were collected from all participants. Whole-exome sequencing was performed in the proband to detect possible causative variants. Sanger sequencing was then conducted in the other family members to verify the candidate variant, and in 100 patients with hypertension and 100 normotensive controls to exclude population genetic polymorphism. Results: We identified a novel frame-shift mutation (c.1691_1693delinsG) in SCNN1B that was responsible for Liddle syndrome in this family. This mutation leads to the substitution of Arg in place of Gln at codon site 564 and generates a new stop codon at 592, influencing the crucial PY motif and resulting in reduced inactivation of the ENaCs. Aside from the proband, eight family members carried the mutation. Intra-familial phenotypic heterogeneity was observed in the blood pressure and serum potassium levels. Amiloride therapy combined with a low sodium diet is effective to alleviate the symptoms of patients with Liddle syndrome. Conclusion: c.1691_1693delinsG, a novel frame-shift mutation in the ß subunit of ENaC, was identified in a Chinese family with Liddle syndrome by whole-exome sequencing. Phenotypic heterogeneity can make diagnosis of Liddle syndrome difficult on the basis of clinical or biochemical characteristics alone. Genetic analysis is a useful tool allowing timely and accurate diagnosis of Liddle syndrome and playing a guiding role in precise treatment of the disease.

Percutaneous Transluminal Renal Angioplasty for Fibromuscular Dysplasia and Prognostic Risk Factors: A Retrospective Chinese Cohort Study.

Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory vascular disease involving small-to-medium-sized arteries. The characteristics of Chinese patients with FMD remain unclear. We retrospectively analyzed the data of patients with renal FMD who underwent percutaneous transluminal renal angioplasty (PTRA) for the first time at Fuwai Hospital between 2010 and 2021. The variables were selected through least absolute shrinkage and selection operator regression (LASSO), and logistic regression models were constructed to identify independent risk factors. A total of 116 patients (52 males, median age at diagnosis, 25.0 years) were enrolled. Elevated blood pressure was the leading complaint. After a median follow-up period of 18.0 months (interquartile range: 6.0-48.0 months), hypertension recurred in 34 patients and restenosis in nine patients, among whom four patients underwent secondary intervention and one patient underwent surgical revascularization. Bilateral renal artery involvement (odds ratio [OR]: 2.61, 95% confidence interval [CI]: 1.11-6.15; p = 0.028) and age at hypertension onset (OR: 0.93, 95% CI: 0.88-0.99; p = 0.018) were independent prognostic factors for adverse outcomes. The results indicate that patients with bilateral renal artery involvement and younger age at hypertension onset are more likely to have poorer clinical outcomes after PTRA, and should be more closely monitored.

Impact of meteorological conditions at multiple scales on ozone concentration in the Yangtze River Delta.

Tropospheric ozone is known to have adverse effects on human health. Ozone pollution events are often associated with specific atmospheric circulation conditions. Therefore, studying the relationship between atmospheric circulation and ozone is particularly important for early warning and forecasting of ozone pollution events. Focusing on the Yangtze River Delta region, particularly in four important large industrial cities (Xuzhou, Nanjing, Shanghai, and Hangzhou) in the Yangtze River Delta, the T-mode objective classification method was applied to classify the weather circulation that mainly affects the Yangtze River Delta region into nine types. Local wind fields for the four industrial cities were classified according to their propensity for ventilation, stagnation, and recirculation based on the Allwine and Whiteman method. Based on the analysis of large-scale atmospheric circulation, we concluded that certain circulation patterns correspond to excessive ozone concentrations, while other circulation patterns correspond to good air quality. Moreover, ozone pollution was not closely related to local regional transmission. The importance of high temperatures in potentiating ozone pollution was also identified in the study area, whereas the effect of relative humidity was negligible. Finally, the importance of the different scale atmospheric motions was analyzed by studying two specific ozone pollution events in Xuzhou area (March, 2019) and Nanjing area (July-August, 2017). This analysis was complemented by HYSPLIT model's outputs to simulate the pollutant diffusion path. Regarding the first episode, ozone concentration is often closely related to the slowly approaching thermal high-pressure system. In the second episode, local transmission had little effect on the generation and spread of ozone pollution. Furthermore, and comparing the circulation conditions with local meteorological factors, it was found that the increase in ozone concentration was often accompanied by higher temperature, and the response to humidity was not clear.

Transcatheter Closure of Patent Ductus Arteriosus via Different Approaches.

Background: There have been marked advances in devices such as Amplatzer Duct Occluder II (ADO-II) or vascular plug through 5Fr delivery sheath for closure of patent ductus arteriosus (PDA) in the past five decades, making it possible for cardiologists to deliver occluders via different approaches. However, comparisons of these different approaches have not been reported. Therefore, the aim of this study was to summarize and compare the advantages of different approaches for PDA closure, and to guide clinical strategies. Methods: This retrospective study included all patients undergoing transcatheter closure of PDA from 2019 to 2020. Patients were matched by 1:1 propensity score matching (PSM). The retrograde femoral artery approach (FAA) and simple vein approach (SVA) groups were compared with the conventional arteriovenous approach (CAA). Results: The average age of the 476 patients was 21.05 ± 21.15 years. Their average weight was 38.23 ± 24.1 kg and average height was 130.14 ± 34.45 cm. The mean diameter of the PDA was 4.29 ± 2.25 mm. There were 127 men and 349 women, comprising 205 adults and 271 children. Among them, 197 patients underwent CAA, 223 underwent SVA, and 56 underwent retrograde FAA. The diameter in the FAA group was smaller than that in the other two groups, but was similar in adults and children. In the PSM comparison of CAA and SVA, 136 patients with CAA and 136 patients with SVA were recruited. Simple vein approach was associated with markedly reduced length of hospital stay, length of operation, and contrast medium usage as compared with CAA (all P < 0.05). In the PSM comparison of FAA and CAA, 30 patients with CAA and 30 patients with FAA were recruited. The operation duration was longer in the CAA than in the FAA group. There were no significant differences in postoperative complications among groups. Conclusion: Patent ductus arteriosus closure by using the SVA and FAA is safe and effective, and has certain advantages in some respects as compared with CAA.

Effects of Composting Different Types of Organic Fertilizer on the Microbial Community Structure and Antibiotic Resistance Genes.

Organic fertilizer is a major carrier that stores and transmits antibiotic resistance genes (ARGs). In the environment, due to the application of organic fertilizers in agriculture, the increasing diversity and abundance of ARGs poses a potential threat to human health and environmental safety. In this paper, the microbial community structure and ARGs in different types of organic fertilizer treated with composting were examined. We found that the abundance and diversity of ARGs in earthworm cast organic fertilizer were the lowest and the highest in chicken manure organic fertilizer. Interestingly, the abundance and diversity of ARGs, especially beta-lactam resistance genes, sulfonamide resistance genes, and macrolide-lincosamide-streptogramin B (MLSB) resistance genes, in organic fertilizers were reduced significantly, while composting caused no significant change in mobile genetic elements (MGEs), where antibiotic deactivation and the use of efflux pumps were the two most dominant mechanisms. It was clear that removal of ARGs became more efficient with increasing reduction in the bacterial abundances and diversity of potential ARG hosts, and integron-mediated horizontal gene transfers (HGTs) played an important role in the proliferation of most ARG types. Therefore, the reduction in ARGs was mainly driven by changes in bacterial community composition caused by composting. Furthermore, rather than HGTs, the diversity and abundance of bacterial communities affected by compost physical and chemical properties were the main drivers shaping and altering the abundance and diversity of ARGs, which was indicated by a correlation analysis of these properties, antibiotic residues, microbial community structure, and ARGs. In general, high-temperature composting effectively removed antibiotic residues and ARGs from these organic fertilizers; however, it cannot prevent the proliferation of MGEs. The insights gained from these results may be of assistance in the safe and rational use of organic fertilizers by indicating the changes in microbial community structure and ARGs in different types of organic fertilizer treated with composting.

Cardiac MR image segmentation and left ventricle surface reconstruction based on level set method.

A two-stage segmentation algorithm is presented to solve the problems of inhomogeneity, weak edges and artifacts exhibited in the magnetic resonance imaging (MRI) images. First, the K-mean clustering algorithm is applied to classify the objects. Then, a speed function based on the clustering results is defined in order to search the rough boundary. Secondly, a speed function of the gradient intensity is constructed to locate the boundary accurately. Due to the lack of deformation information of the boundaries between MR slices, a deformable model is used to reconstruct the shape of the LV: a dynamic equation governing the surface deformation is given; from the slice data, external forces are constructed and elastic forces are provided with mean curvatures of the deformation surface. The level set method is applied to solve the dynamic equation for the LV shape. Experimental results demonstrate the effectiveness of the algorithm listed in the paper.