A moth-eye nanostructured mp-TiO2 film using conventional lithography, nano-imprinting and polydimethyl-siloxane (PDMS) stamping methods is demonstrated for the first time. Power conversion efficiency of the moth-eye patterned perovskite solar cell is improved by ≈11%, which mainly results from increasing light harvesting efficiency by structural optical property.

The production of multiscale architectures is of significant interest in materials science, and the integration of those structures could provide a breakthrough for various applications. Here we report a simple yet versatile strategy that allows for the LEGO-like integrations of microscale membranes by quantitatively controlling the oxygen inhibition effects of ultraviolet-curable materials, leading to multilevel multiscale architectures. The spatial control of oxygen concentration induces different curing contrasts in a resin allowing the selective imprinting and bonding at different sides of a membrane, which enables LEGO-like integration together with the multiscale pattern formation. Utilizing the method, the multilevel multiscale Nafion membranes are prepared and applied to polymer electrolyte membrane fuel cell. Our multiscale membrane fuel cell demonstrates significant enhancement of performance while ensuring mechanical robustness. The performance enhancement is caused by the combined effect of the decrease of membrane resistance and the increase of the electrochemical active surface area.

Several recurrent mutations and epigenetic changes have been identified in advanced gastric cancer, but the genetic alterations associated with early gastric carcinogenesis and malignant transformation remain unclear. We investigated the genomic and transcriptomic landscape of adenomas with low-grade dysplasia (LGD) and high-grade dysplasia (HGD), and intestinal-type early gastric cancer (EGC). The results were validated in an independent cohort that included EGCs directly adjacent to adenoma (EGC-adenomas) that were in the process of malignant transformation, and de novo EGCs that do not seem to have been derived from adenoma. The expression patterns clearly divided into normal, LGD, and EGC, whereas those of HGD overlapped with LGD or EGC. These results suggest that HGD is the critical stage determining malignant transformation. We found that genes related to focal adhesion and extracellular matrix receptor interaction pathways were upregulated as LGD progressed to EGC, whereas canonical Wnt signalling and peroxisome proliferator-activated receptor (PPAR) signalling pathway genes were downregulated in EGC. Genomic alterations such as somatic mutation, gene fusion and copy number variation increased gradually from LGD to EGC. APC mutations were present in 67% of LGDs, 58% of HGDs, and 18% of EGCs. RNF43 mutations were present only in HGD and EGC, and TP53 mutations were present only in EGC. In a validation cohort, RNF43 mutations were present in 35.2% of EGC-adenomas, but in only 8.6% of de novo EGCs. This is the first study to investigate the genomic and transcriptomic landscape of multistep gastric carcinogenesis. We investigated important alterations and their related pathways in each step as tumours progressed from LGD to HGD and eventually to EGC. We suggest that mutations and downregulation of RNF43 may play a critical role in the transition from adenoma to carcinoma. Given these findings and Wnt dependency in tumours with RNF43 mutation, intestinal-type gastric cancer or adenoma with RNF43 mutation might represent a promising indication for Wnt-targeted agents. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The development of a novel approach to achieve high-performance and durable fuel cells is imperative for the further commercialization of proton-exchange (or polymer electrolyte) membrane fuel cells (PEMFCs). In this work, multifunctional dendritic Nafion/CeO 2 structures were introduced onto the cathode side of the interface between a membrane and a catalyst layer through electrospray deposition. The dendritic structures enlarged the interfacial contact area between the membrane and the catalyst layer and formed microscale voids between the catalyst layer and gas diffusion medium. This improved the PEMFC performance through the effective utilization of the catalyst and enhanced mass transport of the reactant. Especially, under lowhumidity conditions, the hygroscopic effect of CeO 2 nanoparticles also boosted the power density of PEMFCs. In addition to the beneficial effects on the efficiency of the PEMFC, the incorporation of CeO 2 , widely known as a radical scavenger, effectively mitigated the free-radical attack on the outer surface of the membrane, where chemical degradation is initiated by radicals formed during PEMFC operation. These multifunctional effects of the dendritic Nafion/CeO 2 structures on PEMFC performance and durability were investigated using various in situ and ex situ measurement techniques.

HIGHLIGHTS • Moth-eye structured polydimethylsiloxane (PDMS) films with different sizes were fabricated to improve the efficiency of perovskite solar cells. • The PDMS with 300-nm moth-eye films significantly reduced light reflection at the front of the glass and therefore enhanced the solar cell efficiency of ~ 21%. • The PDMS with 1000-nm moth-eye films exhibited beautiful coloration. ABSTRACT Large-area polydimethylsiloxane (PDMS) films with variably sized moth-eye structures were fabricated to improve the efficiency of perovskite solar cells. An approach that incorporated photolithography, bilayer PDMS deposition and replication was used in the fabrication process. By simply attaching the moth-eye PDMS films to the transparent substrates of perovskite solar cells, the optical properties of the devices could be tuned by changing the size of the moth-eye structures. The device with 300-nm moth-eye PDMS films greatly enhanced power conversion efficiency of ~ 21% due to the antireflective effect of the moth-eye structure. Furthermore, beautiful coloration was observed on the 1000-nm moth-eye PDMS films through optical interference caused by the diffraction grating effect. Our results imply that moth-eye PDMS films can greatly enhance the efficiency of perovskite solar cells and building-integrated photovoltaics.

The capability of fabricating multiscale structures with desired morphology and incorporating them into engineering applications is key to realizing technological breakthroughs by employing the benefits from both microscale and nanoscale morphology simultaneously. Here, we developed a facile patterning method to fabricate multiscale hierarchical structures by a novel approach called creep-assisted sequential imprinting. In this work, nanopatterning was first carried out by thermal imprint lithography above the glass transition temperature (Tg) of a polymer film, and then followed by creep-assisted imprinting with micropatterns based on the mechanical deformation of the polymer film under the relatively long-term exposure to mechanical stress at temperatures below the Tg of the polymer. The fabricated multiscale arrays exhibited excellent pattern uniformity over large areas. To demonstrate the usage of multiscale architectures, we incorporated the multiscale Nafion films into polymer electrolyte membrane fuel cell, and this device showed more than 10% higher performance than the conventional one. The enhancement was attributed to the decrease in mass transport resistance because of unique cone-shape morphology by creep-recovery effects and the increase in interfacial surface area between Nafion film and electrocatalyst layer.

Intestinal-type gastric carcinoma exhibits a multistep carcinogenic sequence from adenoma to carcinoma with a gradual increase in genomic alterations. But the roles of microRNAs (miRNA) in this multistage cascade are not fully explored. To identify differentially expressed miRNA (DEM) during early gastric carcinogenesis, we performed miRNA microarray profiling with 24 gastric cancers and precursor lesions (7 early gastric cancer [EGC], 3 adenomas with high-grade dysplasia, 4 adenomas with low-grade dysplasia, and 10 adjacent normal tissues). Alterations in the expression of 132 miRNA were detected; these were categorized into three groups based on their expression patterns. Of these, 42 miRNAs were aberrantly expressed in EGC. Five miRNA (miR-26a, miR-375, miR-574-3p, miR-145, and miR-15b) showed decreased expression since adenoma. Expression of two miRNA, miR-200C and miR-29a, was down-regulated in EGCs compared to normal mucosa or adenomas. Six miRNA (miR-601, miR-107, miR-18a, miR-370, miR-300, and miR-96) showed increased expression in gastric cancer compared to normal or adenoma samples. Five representative miRNAs were further validated with RT-qPCR in independent 77 samples. Taken together, these results suggest that the dysregulated miRNA show alterations at the early stages of gastric tumorigenesis and may be used as a candidate biomarker.

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