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Solar-driven interface water evaporation has been demonstrated to be one of the most promising technologies for alleviating global water pollution and water shortage. Although significant advances have been achieved for improving the solar-to-vapor efficiency, the design and fabrication of an all-day solar steam generator with highly efficient evaporation performance still remains a challenge due to the day/night cycle. Herein, we report a novel solar-driven interfacial evaporator composed of a polypyrrole impregnated nylon thread as the photothermal layer and octadecane/carbonized polypyrrole nanotube aerogel composite materials as the photothermal energy storage device to achieve highly efficient all-day solar steam generation. By the combination of photothermal conversion and photothermal energy storage, the as-prepared solar steam evaporator achieves a high evaporation rate of 2.62 kg m−2 h−1 and excellent solar-to-vapor efficiency of 92.7% under 1 kW m−2 illumination. Moreover, the evaporator exhibits excellent salt resistance and there was no obvious salt precipitation observed with 6 h continuous evaporation in 3.5% NaCl aqueous solution. Besides, in the outdoor experiment, the evaporator shows high water production of 8.42 L m−2 in the daytime and 1.22 L m−2 in the nighttime. The findings of this work may provide a novel strategy for the fabrication of the all-day solar-driven interface water evaporation device to mitigate freshwater scarcity, and meanwhile this work lays the foundation for breaking the restriction of the day/night cycle during the solar steam generation process. [ABSTRACT FROM AUTHOR]

The increasing demand for freshwater and the intensification of environment pollution have driven the exploration of high-performance photothermal conversion materials for solar-driven interfacial evaporation (SIE) to produce fresh water. However, the preparation of photothermal conversion materials with high mechanical strength, low cost and sustainability is still a challenge. Herein, an aligned attapulgite-based aerogel with high content of attapulgite (ATP) and high mechanical strength was prepared by chemically/physically cross-linking nano-fibrillated cellulose (NFC), polyvinyl alcohol (PVA) and glutaraldehyde (GA). The resulting ATP-based aerogels were characterized by SEM, N2-adsorption/desorption, axial compression experiment, thermal conductivity test and UV-vis-NIR spectroscopy. The results show that the as-prepared ATP-based aerogels exhibit a three-dimensional macroporous structure, high mechanical strength, low thermal conductivity and excellent light absorption ability. As a solar steam generator, the desired aerogel not only possesses a high energy conversion efficiency of 87.6% in pure water, but also shows highly efficient and stable evaporation performance in harsh environments, such as high-concentration brine water, acid solution, alkali solution, and hot water. In addition, it also exhibits superiorities such as a flexible tunable structure and scalable preparation due to the combination of material selection and rational design. This work provides an insight for the rational design of photothermal conversion materials, showing potential applications in high brine water and harsh environment desalination. [ABSTRACT FROM AUTHOR]

Retinopathy of prematurity (ROP) is a retinal disease which frequently occurs in premature babies with low birth weight and is considered as one of the major preventable causes of childhood blindness. Although automatic and semi-automatic diagnoses of ROP based on fundus image have been researched, most of the previous studies focused on plus disease detection and ROP screening. There are few studies focusing on ROP staging, which is important for the severity evaluation of the disease. To be consistent with clinical 5-level ROP staging, a novel and effective deep neural network based 5-level ROP staging network is proposed, which consists of multi-stream based parallel feature extractor, concatenation based deep feature fuser and clinical practice based ordinal classifier. First, the three-stream parallel framework including ResNet18, DenseNet121 and EfficientNetB2 is proposed as the feature extractor, which can extract rich and diverse high-level features. Second, the features from three streams are deeply fused by concatenation and convolution to generate a more effective and comprehensive feature. Finally, in the classification stage, an ordinal classification strategy is adopted, which can effectively improve the ROP staging performance. The proposed ROP staging network was evaluated with per-image and per-examination strategies. For per-image ROP staging, the proposed method was evaluated on 635 retinal fundus images from 196 examinations, including 303 Normal, 26 Stage 1, 127 Stage 2, 106 Stage 3, 61 Stage 4 and 12 Stage 5, which achieves 0.9055 for weighted recall, 0.9092 for weighted precision, 0.9043 for weighted F1 score, 0.9827 for accuracy with 1 (ACC1) and 0.9786 for Kappa, respectively. While for per-examination ROP staging, 1173 examinations with a 4-fold cross validation strategy were used to evaluate the effectiveness of the proposed method, which prove the validity and advantage of the proposed method. [ABSTRACT FROM AUTHOR]

Background/Aims: Heart failure induced by tachycardia, the most common arrhythmia, is frequently observed in clinical practice. This study was designed to investigate the underlying mechanisms. Methods: Rapid electrical stimulation (RES) at a frequency of 3 Hz was applied on human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for 7 days, with 8 h/day and 24 h/day set to represent short-term and long-term tachycardia, respectively. Age-matched hiPSC-CMs without electrical stimulation or with slow electrical stimulation (1 Hz) were set as no electrical stimulation (NES) control or low-frequency electrical stimulation (LES) control. Following stimulation, JC-1 staining flow cytometry analysis was performed to examine mitochondrial conditions. Apoptosis in hiPSC-CMs was evaluated using Hoechst staining and Annexin V/propidium iodide (AV/PI) staining flow cytometry analysis. Calcium transients and L-type calcium currents were recorded to evaluate calcium homeostasis. Western blotting and qPCR were performed to evaluate the protein and mRNA expression levels of apoptosis-related genes and calcium homeostasis-regulated genes. Results: Compared to the controls, hiPSC-CMs following RES presented mitochondrial dysfunction and an increased apoptotic percentage. Amplitudes of calcium transients and L-type calcium currents were significantly decreased in hiPSC-CMs with RES. Molecular analysis demonstrated upregulated expression of Caspase3 and increased Bax/Bcl-2 ratio. Genes related to calcium re-sequence were downregulated, while phosphorylated Ca2+/calmodulin-dependent protein kinase II (CaMKII) was significantly upregulated following RES. There was no significant difference between the NES control and LES control groups in these aspects. Inhibition of CaMKII with 1 µM KN93 partly reversed these adverse effects of RES. Conclusion: RES on hiPSC-CMs disturbed calcium homeostasis, which led to mitochondrial stress, promoted cell apoptosis and caused electrophysiological remodeling in a time-dependent manner. CaMKII played a central role in the damages induced by RES, pharmacological inhibition of CaMKII activity partly reversed the adverse effects of RES on both structural and electrophysiological properties of cells. [ABSTRACT FROM AUTHOR]