Template Engineering of CuBi2 O4 Single-Crystal Thin Film Photocathodes.

To develop strategies for efficient photo-electrochemical water-splitting, it is important to understand the fundamental properties of oxide photoelectrodes by synthesizing and investigating their single-crystal thin films. However, it is challenging to synthesize high-quality single-crystal thin films from copper-based oxide photoelectrodes due to the occurrence of significant defects such as copper or oxygen vacancies and grains. Here, the CuBi2 O4 (CBO) single-crystal thin film photocathode is achieved using a NiO template layer grown on single-crystal SrTiO3 (STO) (001) substrate via pulsed laser deposition. The NiO template layer plays a role as a buffer layer of large lattice mismatch between CBO and STO (001) substrate through domain-matching epitaxy, and forms a type-II band alignment with CBO, which prohibits the transfer of photogenerated electrons toward bottom electrode. The photocurrent densities of the CBO single-crystal thin film photocathode demonstrate -0.4 and -0.7 mA cm-2 at even 0 VRHE with no severe dark current under illumination in a 0.1 m potassium phosphate buffer solution without and with H2 O2 as an electron scavenger, respectively. The successful synthesis of high-quality CBO single-crystal thin film would be a cornerstone for the in-depth understanding of the fundamental properties of CBO toward efficient photo-electrochemical water-splitting.

Artificial Intelligence for Detection of Cardiovascular-Related Diseases from Wearable Devices: A Systematic Review and Meta-Analysis.

PURPOSE: Several artificial intelligence (AI) models for the detection and prediction of cardiovascular-related diseases, including arrhythmias, diabetes, and sleep apnea, have been reported. This systematic review and meta-analysis aimed to identify AI models developed for or applicable to wearable and mobile devices for diverse cardiovascular-related diseases. MATERIALS AND METHODS: The searched databases included Medline, Embase, and Cochrane Library. For AI models for atrial fibrillation (AF) detection, a meta-analysis of diagnostic accuracy was performed to summarize sensitivity and specificity. RESULTS: A total of 102 studies were included in the qualitative review. There were AI models for the detection of arrythmia (n=62), followed by sleep apnea (n=11), peripheral vascular diseases (n=6), diabetes mellitus (n=5), hyper/hypotension (n=5), valvular heart disease (n=4), heart failure (n=3), myocardial infarction and cardiac arrest (n=2), and others (n=4). For quantitative analysis of 26 studies reporting AI models for AF detection, meta-analyzed sensitivity was 94.80% and specificity was 96.96%. Deep neural networks showed superior performance [meta-analyzed area under receiver operating characteristics curve (AUROC) of 0.981] compared to conventional machine learning algorithms (meta-analyzed AUROC of 0.961). However, AI models tested with proprietary dataset (meta-analyzed AUROC of 0.972) or data acquired from wearable devices (meta-analyzed AUROC of 0.977) showed inferior performance than those with public dataset (meta-analyzed AUROC of 0.986) or data from in-hospital devices (meta-analyzed AUROC of 0.983). CONCLUSION: This review found that AI models for diverse cardiovascular-related diseases are being developed, and that they are gradually developing into a form that is suitable for wearable and mobile devices.

Hydrolysis Reaction and Amorphization of Ce-Ti Oxide Catalysts During Synthesis.

The change in the crystallinity of Ce-Ti oxide nanocatalysts with different water contents was investigated in terms of the local atomic structure and the surface atomic concentration. The crystallization of TiO2, which was induced by the hydrolysis of the Ti precursor, was observed in the catalyst synthesized via a liquid phase reaction employing a mixture of ethanol and distilled water as the solvent. The hydrolysis reaction of the Ti precursor was impeded in the solvent mixture of ethanol and anhydrous ethanol. CeO2 nanocrystallization occurred due to the suppression of the TiO2 crystal growth. Low crystallinity of the catalyst synthesized in a single anhydrous ethanol solvent was observed through the broadened X-ray diffraction (XRD) peak and the diffused ring pattern in transmission electron microscopic (TEM) images. In addition, the Ce-O and Ce-Ce bond lengths of the catalyst synthesized using the single solvent decreased beyond those of the catalysts synthesized in the mixed solvent, indicating the amorphization of the catalyst. It was also verified that the inhibition of the precursor crystallization during the synthesis led to the enhanced dispersion of the nanocatalyst, compared to the stoichiometry of the surface atomic concentration.