Extensible artificial intelligence model predicts post-ablation AF recurrence using coronary sinus electrogram

Background

Atrial fibrillation (AF) is a major public health problem with significant adverse outcomes and catheter ablation is a widely adopted treatment. The CABANA trial showed that catheter ablation reduced AF recurrence to a greater extent than medications. However, some of patients who underwent this procedure still experience relapse. Here, we present an innovative way to identify this subgroup using an artificial intelligence (AI) -assisted coronary sinus electrogram.

Hypothesis

Our hypothesis is that credible features in the electrogram can be extracted by AI for prediction, therefore rigorous drug administration, close follow-up or potential second procedure can be applied to these patients.

Methods

67 patients from two independent hospitals (SPH & ZSH) with non-valvular persistent AF undergoing circumferential pulmonary vein isolation were enrolled in this study, 23 of which experienced recurrence 6 months after the procedure. We collected standard 2.5-second fragments of coronary sinus electrogram from ENSITE NAVX (SPH) and Carto (ZSH)system before the ablation started. A total of 1429 fragments were obtained and a transfer learning-based ResNet model was employed in our study. Fragments from ZSH were used for training and SPH for validation of deep convolutional neural networks (DCNN). The AI model performance was evaluated by accuracy, recall, precision, F-Measure and AUC.

Results

The prediction accuracy of the DCNN in single center reached 96%, while that in different ablation systems reached 74.3%. Also, the algorithm yielded values for the AUC, recall, precision and F-Measure of 0.76, 86.1%, 95.9% and 0.78, respectively, which shows satisfactory classification results and extensibility in different cardiology centers and brands of electroanatomic mapping instruments.

Conclusions

Our work has revealed the potential intrinsic correlation between coronary sinus electrical activity and AF recurrence using DCNN-based model. Moreover, the DCNN model we developed shows great prospects in the relapse prediction for personalized post-procedural management.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): The National Natural Science Foundation of China

LncRNA MALAT1 inhibits osteogenic differentiation of mesenchymal stem cells in osteoporosis rats through MAPK signaling pathway

OBJECTIVE

The aim of this study was to explore whether long non-coding ribonucleic acid metastasis-associated lung adenocarcinoma transcript 1 (lncRNA MALAT1) could lead to osteoporosis (OP) by stimulating the activation of the mitogen-activated protein kinase (MAPK) signaling pathway.

MATERIALS AND METHODS

The OP model was first successfully established in rats. The expression of lncRNA MALAT1 in OP rats and normal rats was detected via quantitative Polymerase Chain Reaction (qPCR). Bone marrow mesenchymal stem cells (BMSCs) were cultured and transfected to establish the MALAT1 knockdown model. Subsequently, the apoptosis of mesenchymal stem cells in MALAT1 siRNA group and NC siRNA group was detected via flow cytometry. Meanwhile, the expressions of the MAPK signaling pathway proteins related to OP were detected via Western blotting. After alkaline phosphatase (ALP) staining in cells of both groups, early osteogenic differentiation of BMSCs was observed.

RESULTS

The results of qPCR showed that the expression of lncRNA MALAT1 in OP rats was significantly lower than that of normal rats. It was observed under a fluorescence microscope that there were a large number of siRNA particles in BMSCs. The expression of lncRNA MALAT1 in cells was detected via Real Time-fluorescence qPCR as well. The results indicated that siRNA transfection could effectively inhibit the expression of lncRNA MALAT1, indicating successful transfection. Flow cytometry revealed that no significant difference was observed in the apoptosis of BMSCs between the MALAT1 siRNA group and NC siRNA group. Besides, the results of Western blotting showed that the expression levels of the MAPK signaling pathway-related proteins extracellular signal-regulated kinase 1/2 (ERK1/2) and P38 in MALAT1 siRNA group were significantly higher than those of the NC siRNA group. This indicated that inhibiting the expression of lncRNA MALAT1 might promote the activation of the OP-related MAPK pathway. According to the results of ALP staining, the depth of staining in MALAT1 siRNA group was markedly declined when compared with the NC siRNA group. Quantification of ALP activity demonstrated that ALP activity in the MALAT1 siRNA group was markedly declined compared with the NC siRNA group. The above results suggested that suppressing the expression of lncRNA MALAT1 could reduce the ALP activity of BMSCs. Furthermore, lncRNA MALAT1 inhibited osteogenic differentiation of BMSCs.

CONCLUSIONS

LncRNA MALAT1 was lowly expressed in OP rats. Moreover, it inhibited osteogenic differentiation of BMSCs by enhancing the activation of the MAPK signaling pathway, thereby promoting OP progression.

[Ovarian Sertoli-Leydig cell tumors: DICER1 hotspot mutations and associated clinicopathological features]

Objective: To investigate DICER1 hotspot mutations in ovarian Sertoli-Leydig cell tumor (SLCT) and its associated clinicopathological features. Methods: Forty-three SLCTs and 40 other sex cord-stromal tumors (SCSTs) diagnosed between 2010 and 2017 at Fudan University Shanghai Cancer Center were examined for somatic DICER1 hotspot mutations by Sanger sequencing. The associations between mutation status and clinicopathological features, including patient age, tumor differentiation and recurrence, were analyzed. Results: Somatic DICER1 mutations were found in 51% (22/43) of SLCTs, while none in the other 40 SCSTs. The most common mutation of DICER1 was p.D1709N in exon 24 (41%, 9/22) and the second most common mutation of DICER1 was p.E1813K in exon 25 (14%, 3/22). A novel frameshift mutation (c.5464delG, p.M1837fs*16) was identified in one SLCT with microcystic pattern. Mutations were more likely to occur in patients under forty years of age (P=0.046), whereas no significant associations were found between DICER1 mutations and clinical symptoms, morphology or tumor recurrence. Conclusions: Somatic DCIER1 hotspot mutations are specifically found in SLCT and may serve as an ancillary marker in differential diagnosis of SLCT from other SCST. The mutations occur more often in young patients (<40 years old). Additional studies are warranted to examine the associations between DICER1 mutations and clinicopathological features and prognosis of SLCT.

Three-dimensional hydrogen distribution and quantitative determination of titanium alloys via neutron tomography

Thermohydrogen processing (THP) is an attractive technique that uses hydrogen as a temporary alloying element to modify the microstructure and properties of titanium alloys. However, the hydrogen diffusion behavior during THP is not fully understood owing to limited scope of methods to detect hydrogen distributions. Herein, we introduce neutron tomography as an efficient tool for three-dimensional (3D) hydrogen distribution analysis and quantitative determination in hydrogenated titanium alloys after THP. Thus motivated, a series of calibration samples of Ti-6Al-4V alloys with varying hydrogen contents were prepared and elaborated neutron tomography experiments and image data processing were performed. In this way, the 3D hydrogen distribution of the hydrogenated samples was obtained and the quantitative relationship between the hydrogen contents and the tomographic images was determined. To the best of our knowledge, this enabled for the first time the direct 3D visualization and characterization of the hydrogen distribution and concentration in titanium alloys after THP. It was deduced that hydrogen diffused from the surface to the interior of the hydrogenated sample in all directions during THP. In addition, the feasibility of neutron tomography for 3D quantitative hydrogen distribution was validated using continuous sample segmentation and the traditional heat conductivity method. Consequently, neutron tomography can be efficient for determining the hydrogen distribution and concentration in bulk metals and shed light on the hydrogen diffusion behavior and the mechanism of hydrogen-related materials and processing.

Sequentially addressable dielectrophoretic array for high-throughput sorting of large-volume biological compartments

Droplet microfluidics has become a powerful tool in precision medicine, green biotechnology, and cell therapy for single-cell analysis and selection by virtue of its ability to effectively confine cells. However, there remains a fundamental trade-off between droplet volume and sorting throughput, limiting the advantages of droplet microfluidics to small droplets (<10 pl) that are incompatible with long-term maintenance and growth of most cells. We present a sequentially addressable dielectrophoretic array (SADA) sorter to overcome this problem. The SADA sorter uses an on-chip array of electrodes activated and deactivated in a sequence synchronized to the speed and position of a passing target droplet to deliver an accumulated dielectrophoretic force and gently pull it in the direction of sorting in a high-speed flow. We use it to demonstrate large-droplet sorting with ~20-fold higher throughputs than conventional techniques and apply it to long-term single-cell analysis of Saccharomyces cerevisiae based on their growth rate.

[Breast schistosomiasis japonica: a case report]

A case with breast schistosomiasis japonica was reported.

Constraints on Lorentz Invariance Violation from HAWC Observations of Gamma Rays above 100 TeV

Because of the high energies and long distances to the sources, astrophysical observations provide a unique opportunity to test possible signatures of Lorentz invariance violation (LIV). Superluminal LIV enables the decay of photons at high energy. The high altitude water Cherenkov (HAWC) observatory is among the most sensitive gamma-ray instruments currently operating above 10 TeV. HAWC finds evidence of 100 TeV photon emission from at least four astrophysical sources. These observations exclude, for the strongest of the limits set, the LIV energy scale to 2.2×10^{31}  eV, over 1800 times the Planck energy and an improvement of 1 to 2 orders of magnitude over previous limits.

[The performance of visual photoscreening for Chinese preschool children aged 4 to 5 years]

Objective: To assess the accuracy of photoscreening for detecting refractive amblyopia risk factors (ARFs) in Chinese preschool children aged 4 to 5 years. Methods: A cross-sectional study. Comprehensive ocular examinations were conducted for preschool children in Nanjing, China from September to December, 2016. Photoscreening (Plusoptix A12C) was applied for refractive screening without cycloplegia. Voluntary children and children suspected of eyes abnormalities received cycloplegic retinoscopy (CR). Results of photoscreening and CR were compared using Wilcoxon signed rank test, and Bland-Altman plot were used to assess the agreement between the photoscreener and CR. According to the updated preschool vision screening guidelines from American Association for Pediatric Ophthalmology and Strabismus (AAPOS) in 2013, CR was adopted for identifying children with ARFs, which was considered as a golden standard. Based on the golden standard, the accuracy of 5 sets of referral criteria (including sensitivity standard, Matta/Silbert standard, AAPOS2013 standard, Alaska Blind Child Discovery standard, specificity standard) for photoscreener were tested. Receiver operating characteristics curves were constructed applied to evaluate the quality of the photoscreener in refractive ARFs detection and to find probably the best cut-off points. Results: In total, 1 986 children [mean age, (4.57±0.29) years] received comprehensive examinations, including 1 084 boys and 902 girls. The test ability of photoscreening was 99.04% (1 967/1 986) in the preschool children, and 96.56%(1 827/1 892) of the children got a reliable result within three screening attempts. In 538 children who had data of CR, refractive error of one child exceeded the upper limit of the photoscreener value setting, which was directly categorized as hyperopia, so in the end, 537 children were included to analyze the comparison between the two tests. The measurement values of photoscreening were lower than those of CR in sphere, cylinder and spherical equivalent [(0.75 (0.50, 1.25) D vs. 1.25 (1.00, 1.75) D, Z=-10.36, P<0.01; -0.50 (-0.75, -0.25) D vs. -0.25 (-0.75, 0.00) D, Z=-11.10, P<0.01; 0.63 (0.38, 0.88) D vs. 1.00 (0.75, 1.50) D, Z=-13.33, P<0.01]. The 95% limit of agreement cover rates between the photoscreening and CR in sphere, cylinder and spherical equivalent was 96.28% (517/537), 95.34% (512/537) and 96.65% (519/537), respectively. Based on the golden standard, 47 (8.74%) children had refractive ARFs, and the range of sensitivity, specificity, Youden index, positive predictive values and negative predictive values for detecting refractive ARFs of the 5 common used referral criteria was from 63.83% to 97.87%, from 53.36% to 97.56%, from 0.51 to 0.80, from 16.73% to 74.51% and from 96.57% to 99.62%, respectively. Considering particular refractive ARFs on the basis of the receiver operating characteristic curves, the optimal cut-off point for astigmatism was set at 1.38 D. Conclusion: Photoscreening could be an applicable tool to detect refractive ARFs in preschool children. (Chin J Ophthalmol, 2020, 56: 189-196).

Robust weak antilocalization due to spin-orbital entanglement in Dirac material Sr3SnO

The presence of both inversion (P) and time-reversal (T) symmetries in solids leads to a double degeneracy of the electronic bands (Kramers degeneracy). By lifting the degeneracy, spin textures manifest themselves in momentum space, as in topological insulators or in strong Rashba materials. The existence of spin textures with Kramers degeneracy, however, is difficult to observe directly. Here, we use quantum interference measurements to provide evidence for the existence of hidden entanglement between spin and momentum in the antiperovskite-type Dirac material Sr3SnO. We find robust weak antilocalization (WAL) independent of the position of EF. The observed WAL is fitted using a single interference channel at low doping, which implies that the different Dirac valleys are mixed by disorder. Notably, this mixing does not suppress WAL, suggesting contrasting interference physics compared to graphene. We identify scattering among axially spin-momentum locked states as a key process that leads to a spin-orbital entanglement.

Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely galactic in origin. Three sources continue emitting past 100 TeV, making this the highest-energy gamma-ray source catalog to date. We report the integral flux of each of these objects. We also report spectra for three highest-energy sources and discuss the possibility that they are PeVatrons.

Seven Novel and Three Known Mutations in FOXL2 in 10 Chinese Families with Blepharophimosis Syndrome

BACKGROUND

Blepharophimosis syndrome (BPES) is characterized by eyelid malformation with occasional premature ovarian failure. Mutations in FOXL2 underlie a fraction of BPES cases.

OBJECTIVE

We aimed to investigate the genetic basis of BPES in 26 Chinese families that included 78 patients.

METHODS

We performed ophthalmological examinations on each family member. We used Sanger sequencing to screen FOXL2 exons and their flanking sequences. We also performed bioinformatics studies, structural modeling and pathogenicity evaluations on all identified variations. Literature was reviewed and genotype-phenotype correlation analysis was performed.

RESULTS

The patients had typical manifestations of BPES. Ten mutations were identified in ten of the twenty-six families. Among these, seven were novel mutations. These included the six truncating mutations, p.Glu69*, p.Gly256Glyfs*14, p.Ala14Serfs*135, p.Pro333Profs*200, p.Pro290Leufs*70, and p.Pro157Profs*91, and one missense mutation, p.Tyr59Cys. The mutations were scattered within the gene, and no mutational hotspots were found. Genotype-phenotype correlation analysis showed that frameshift or nonsense mutations were correlated with type I BPES, while in-frame or missense mutations were associated with type II BPES.

CONCLUSION

We report the largest BPES cohort in China thus far as well as seven novel mutations in FOXL2. The identification of novel mutations has not only expanded the mutational spectrum of the gene (which is valuable for mutation detection-based screening) but also suggests that most mutations within the Chinese population may not have been characterized yet.