Feasibility and validity of using deep learning to reconstruct 12-lead ECG from three­lead signals.

BACKGROUND: In the field of mobile health, portable dynamic electrocardiogram (ECG) monitoring devices often have a limited number of lead electrodes due to considerations, such as portability and battery life. This situation leads to a contradiction between the demand for standard 12­lead ECG information and the limited number of leads collected by portable devices. METHODS: This study introduces a composite ECG vector reconstruction network architecture based on convolutional neural network (CNN) combined with recurrent neural network by using leads I, II, and V2. This network is designed to reconstruct three­lead ECG signals into 12­lead ECG signals. A 1D CNN abstracts and extracts features from the spatial domain of the ECG signals, and a bidirectional long short-term memory network analyzes the temporal trends in the signals. Then, the ECG signals are inputted into the model in a multilead, single-channel manner. RESULTS: Under inter-patient conditions, the mean reconstructed Root mean squared error (RMSE) for precordial leads V1, V3, V4, V5, and V6 were 28.7, 17.3, 24.2, 36.5, and 25.5 µV, respectively. The mean overall RMSE and reconstructed Correlation coefficient (CC) were 26.44 µV and 0.9562, respectively. CONCLUSION: This paper presents a solution and innovative approach for recovering 12­lead ECG information when only three­lead information is available. After supplementing with comprehensive leads, we can analyze the cardiac health status more comprehensively across 12 dimensions.

Preparation and Characterization of the Forward Osmosis Membrane Modified by MXene Nano-Sheets.

The Forward Osmosis (FO) membrane was the core of FO technology. Obtaining a high water flux while maintaining a low reverse solute flux has historically been considered the gold standard for a perfect FO membrane. In a thin-film composite FO membrane, the performance of the membrane was determined not only by the material and structure of the porous support layer but also by the structural and chemical properties of the active selective layer. Researchers have selected numerous sorts of materials for the FO membranes in recent years and have produced exceptional achievements. Herein, the performance of the modified FO membrane constructed by introducing new two-dimensional nanomaterial MXene nano-sheets to the interfacial polymerization process was investigated, and the performance of these modified membranes was investigated using a variety of characterization and testing methods. The results revealed that the MXene nano-sheets played an important role in improving the performance of the FO membrane. Because of the hydrophilic features of the MXene nano-sheets, the membrane structure may be tuned within a specific concentration range, and the performance of the modified FO membrane has been significantly enhanced accordingly. The optimal membrane water flux was boosted by around 80%, while its reverse solute flux was kept to a minimum of the resultant membranes. It showed that the addition of MXene nanosheets to the active selective layer could improve the performance of the FO membrane, and this method showed promising application prospects.

Comparison and optimization of extraction protocol for intracellular phosphorus and its polyphosphate in enhanced biological phosphorus removal (EBPR) sludge.

Intracellular polyphosphate (poly-P) plays important roles in Enhanced biological phosphorus removal (EBPR) process, but an effective and reliable protocol for extracting intracellular P and its poly-P in EBPR sludge without hydrolysis of poly-P has not been setup yet. In the study, it was revealed that the severe hydrolysis of intracellular poly-P occurred during the different extraction processes, such as acid (i.e., HClO4, H2SO4 and HCl), basic (i.e., NaOH and KOH) and freezing-grind (under different solid-liquid ratios), but it did not occur during ultrasonic extraction process. The optimal extraction process of the ultrasonic protocol was 10 w/mL of ultrasonic power density and 15 min of ultrasonic time, when the extraction efficiency of intracellular P was 88.24 ±â€¯1.56%. In addition, the extraction efficiency of intracellular P could be furtherly improved by that the 0.75 mol/L LiCl solution was used to resuspend the bacterial cell before ultrasonic extraction (i.e., LiCl-ultrasonic protocol). The ultrasonic protocol was more suitable to extract the intracellular P and its poly-P of EBPR sludge than the other 4 protocols (i.e., PCA-NaOH, EDTA-NaOH, freezing-grind and LiCl-ultrasonic), which had the technical characteristics of (i) with relatively high extraction efficiency of intracellular P, (ii) without hydrolysis of intracellular poly-P, (iii) with weak noise signal in 31P NMR spectrum and (iv) with simple extraction process and short extraction time. It was founded by the ultrasonic protocol that there was the high content (82.88%-89.79% of intracellular P content) of intracellular poly-P with long average chain length (376.4-383.2) in the EBPR sludges. Importantly, it was confirmed that the EBPR process was related to the combined action of extracellular and intracellular poly-P using a new fractionation method of P in EBPR sludge, which included the ultrasonic protocol at high power density for extracting the intracellular P and its poly-P.

Graphene Oxide Incorporated Forward Osmosis Membranes With Enhanced Desalination Performance and Chlorine Resistance.

In this work, grapheme oxide (GO) nano-sheets were synthesized and dispersed in the aqueous phase for the interfacial polymerization (IP) process to develop a new type of thin-film composite (TFC) membranes for forward osmosis (FO) applications. The effects of the GO concentrations on the membrane surfaces and cross-sectional morphologies and FO desalination performances of the as-prepared TFC membranes were investigated systematically. Compared with the control membrane, the optimal GO-incorporated TFC membrane displayed higher water flux, less specific reverse solute flux (SRSF) and lower structure parameter. Moreover, the optimized membrane showed 75.0 times higher chlorine resistance than the control membrane. In general, these new type of membranes could be an effective strategy to fabricate high-performance FO membranes with good desalination performance and chlorine resistance.

The roles of loosely-bound and tightly-bound extracellular polymer substances in enhanced biological phosphorus removal.

Extracellular polymeric substances (EPS) have be founded to participate in the process of enhanced biological phosphorus removal (EBPR), but the exact role of EPS in EBPR process is unclear. In this work, the roles of loosely-bound EPS (LB-EPS), tightly-bound EPS (TB-EPS) and microbial cell in EBPR were explored, taking the activated sludge from 4 lab-scale A/O-SBR reactors with different temperatures and organic substrates as objects. It was founded that the P of EBPR activated sludge was mainly stored in TB-EPS, but the P of non-EBPR activated sludge was primarily located in microbial cell. The P release and uptake of EBPR activated sludge was attributed to the combined action of TB-EPS and microbial cell. Furthermore, TB-EPS played an more important role than microbial cell in EBPR process. With the analysis of 31P NMR spectroscopy, both polyP and orthoP were the main phosphorus species of TB-EPS in EBPR sludge, but only orthoP was the main phosphorus species of LB-EPS and microbial cell. During the anaerobic-aerobic cycle, the roles of LB-EPS, TB-EPS and microbial cell in transfer and transformation of P in EBPR sludge were obviously different. LB-EPS transported and retained orthoP, and microbial cell directly anaerobically released or aerobically absorbed orthoP. Importantly, TB-EPS not only transported and retained orthoP, but also participated in biological phosphorus accumulation. The EBPR performance of sludge was closely related with the polyp in TB-EPS, which might be synthesized and decomposed by extracellular enzyme.

[Effects of astaxanthin on renal fibrosis and cell apoptosis induced by partial unilateral ureteral obstruction in rats].

OBJECTIVE: To study the effects of astaxanthin on renal fibrosis and apoptosis induced by partial unilateral ureteral obstruction (UUO) in rats. METHODS: Ninety-six male adult SD rats were randomized into 6 equal groups, namely the blank control group, sham-operated group, UUO group, and astaxanthin group at high, medium, and low doses. Left ureteral ligation was performed in UUO and astaxanthin groups, and two days before the operation, the rats in astaxanthin groups were lavaged with 25, 50, or 100 mg/kg astaxanthin daily for 14 days, while the same volume of saline was given to rats in UUO group and sham-operated group. Renal pathological in the rats was observed with HE staining, and the expression levels of TGF-ß1, SGK1, and CTGF in the left kidney were detected immunohistochemically; the expression level of Bcl-2 and Bax were detected using Bcl-2 and Bax detection kits. RESULTS: Compared to UUO group, high- and medium-dose astaxanthin groups showed obviously ameliorated renal pathologies and reduced expressions of TGF-ß1, SGK1, and CTGF in the left kidney with lessened renal cell apoptosis. CONCLUSION: Astaxanthin can reduce UUO-induced renal fibrosis and renal cell apoptosis, demonstrating the renoprotective effect of astaxanthin against renal fibrosis.