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Flexible transparent electrodes are in significant demand in applications including solar cells, light-emitting diodes, and touch panels. The combination of high optical transparency and high electrical conductivity, however, sets a stringent requirement on electrodes based on metallic materials. To obtain practical sheet resistances, the visible transmittance of the electrodes in previous studies is typically lower than the transparent substrates the electrode structures are built on, namely, the transmittance relative to the substrate is <100%. Here, we demonstrate a flexible dielectric-metal-dielectric-based electrode with ~88.4% absolute transmittance, even higher than the ~88.1% transmittance of the polymer substrate, which results in a relative transmittance of ~100.3%. This non-trivial performance is achieved by leveraging an optimized dielectric-metal-dielectric structure guided by analytical and quantitative principles described in this work, and is attributed to an ultra-thin and ultra-smooth copper-doped silver film with low optical loss and low sheet resistance. Designing flexible and transparent electrodes for high-performance optoelectronic devices remains a challenge. Here, the authors presented conductive and flexible dielectric-metal-dielectric multi-layers electrodes based on Cu-doped Ag film (thickness of 6.5 nm) with 100.3% relative transmittance.

Numerous neurodegenerative diseases show deposition of protein aggregates, which are thought to cause neuronal damage. This Review discusses how cell-to-cell transmission of these pathogenic misfolded proteins is involved in initiation and progression of the disease and examines the clinical relevance of different strains in the heterogeneity of neurodegenerative disorders. A common feature of many neurodegenerative diseases is the deposition of β-sheet-rich amyloid aggregates formed by proteins specific to these diseases. These protein aggregates are thought to cause neuronal dysfunction, directly or indirectly. Recent studies have strongly implicated cell-to-cell transmission of misfolded proteins as a common mechanism for the onset and progression of various neurodegenerative disorders. Emerging evidence also suggests the presence of conformationally diverse 'strains' of each type of disease protein, which may be another shared feature of amyloid aggregates, accounting for the tremendous heterogeneity within each type of neurodegenerative disease. Although there are many more questions to be answered, these studies have opened up new avenues for therapeutic interventions in neurodegenerative disorders.

Inflammation can act as a crucial mediator of epithelial-to-mesenchymal transition (EMT). In this study, we show that oncostatin M (OSM) is expressed in an autocrine/paracrine fashion in invasive breast carcinoma. OSM stimulation promotes spontaneous lung metastasis of MCF-7 xenografts in nude mice. A conspicuous epigenetic transition was induced by OSM stimulation not only in breast cancer cell lines but also in MCF-7 xenografts in nude mice. The expression of miR-200 and let-7 family members in response to OSM stimulation was downregulated in a signal transducer and activator of transcription factor 3 (Stat3)-dependent manner, resulting in comprehensive alterations of the transcription factors and oncoproteins targeted by these microRNAs. Inhibition of Stat3 activation or the ectopic expression of let-7 and miR-200 effectively reversed the mesenchymal phenotype of breast cancer cells. Stat3 promotes the transcription of Lin-28 by directly binding to the Lin-28 promoter, resulting in the repression of let-7 expression and concomitant upregulation of the let-7 target, high-mobility group A protein 2 (HMGA2). Knock down of HMGA2 significantly impairs OSM-driven EMT. Our data indicate that downregulation of let-7 and miR-200 levels initiates and maintains OSM-induced EMT phenotypes, and HMGA2 acts as a master switch of OSM-induced EMT. These findings highlight the importance of Stat3-coordinated Lin-28B–let-7–HMGA2 and miR-200–ZEB1 circuits in the cytokine-mediated phenotypic reprogramming of breast cancer cells.

We experimentally demonstrate and theoretically analyze high Q-factor (~10 7 ) capillary-based optical ring resonators for non-contact detection of air-coupled ultrasound. Noise equivalent pressures in air as low as 215 mPa/√Hz and 41 mPa/√Hz at 50 kHz and 800 kHz in air, respectively, are achieved. Furthermore, non-contact detection of air-coupled photoacoustic pulses optically generated from a 200 nm thick Chromium film is demonstrated. The interaction of an acoustic pulse and the mechanical mode of the ring resonator is also studied. Significant improvement in detection bandwidth is demonstrated by encapsulating the ring resonator in a damping medium. Our work will enable compact and sensitive ultrasound detection in many applications, such as air-coupled non-destructive ultrasound testing, photoacoustic imaging, and remote sensing. It will also provide a model system for fundamental study of the mechanical modes in the ring resonator.

Colour and spectral imaging systems typically use filters and glass prisms to disperse light of different wavelengths. With the miniaturization of integrated devices, current research on imaging sensors focuses on novel designs aiming at high efficiency, low power consumption and slim dimension, which poses great challenges to the traditional colourant-based filtering and prism-based spectral splitting techniques. In this context, surface plasmon-based nanostructures are attractive due to their small dimensions and the ability to efficiently manipulate light. In this article we use selective conversion between free-space waves and spatially confined modes in plasmonic nanoresonators formed by subwavelength metal–insulator–metal stack arrays to show that the transmission spectra through such arrays can be well controlled by using simple design rules, and high-efficiency colour filters capable of transmitting arbitrary colours can be achieved. These artificial nanostructures provide an approach for high spatial resolution colour filtering and spectral imaging with extremely compact device architectures. With the miniaturization of integrated optical devices, traditional colour filters are increasingly bulky. To supersede these, the authors devise a plasmonic metal–insulator–metal nanostructured array that can filter colours with high spatial and band resolution.

Recent years have witnessed a rapid development in the field of structural coloration, colors generated from the interaction of nanostructures with light. Compared to conventional color generation based on pigments and dyes, structural color generation exhibits unique advantages in terms of spatial resolution, operational stability, environmental friendliness, and multiple functionality. Here, we discuss recent development in structural coloration based on layered thin films and optical metasurfaces. This review first presents fundamentals of color science and introduces a few popular color spaces used for color evaluation. Then, it elaborates on representative physical mechanisms for structural color generation, including Fabry–Pérot resonance, photonic crystal resonance, guided mode resonance, plasmon resonance, and Mie resonance. Optimization methods for efficient structure parameter searching, fabrication techniques for large-scale and low-cost manufacturing, as well as device designs for dynamic displaying are discussed subsequently. In the end, the review surveys diverse applications of structural colors in various areas such as printing, sensing, and advanced photovoltaics.

Purpose To estimate the prevalence of myopia among primary and middle school-aged students in Guangzhou and to explore the potentially contributing factors to myopia. Methods This cross-sectional study was based on a sample of students in grades 1–6 and grades 7–9. Data were collected from refractive error measurements and a structured questionnaire. Results A total of 3055 participants were involved in this analysis, and the overall prevalence of myopia was 47.4% (95% confidence interval (CI)= 45.6–49.2%). The prevalence of myopia in students increased along with the growth of grade level; the prevalence of myopia in students in grade 1 was only 0.2%, as it increased to 38.8% in students in grade 3, and the rate was the highest (68.4%) in students in grade 9. Girls were at a higher risk of myopia than boys (adjusted odds ratio=1.22, 95% CI=1.04–1.44). Both male and female students whose distance of reading was longer than 25 cm were less likely to have myopia and who have one or two myopic parents were at a higher risk of myopia. In addition, reading for pleasure more than 2 h per day (adjusted odds ratio=1.84, 95% CI=1.09–3.12) was only positively associated with myopia in boys and spending time watching television per week was only positively associated with myopia in girls. Conclusion Myopia in students is a significant public health problem in Guangzhou. Female gender, higher grade, longer time spent for near work, shorter distance of near work, and parental myopia were shown to be associated with the increasing risk of myopia in children.

To move beyond colorant-based pigmentation display technologies, a variety of photonic and plasmonic crystal based structures have been designed and applied as colour filters. Nanostructure based colour filtering offers increased efficiencies, low power consumption, slim dimensions and enhanced resolution. However, incident angle tolerance still needs to be improved. In this work, we propose a new scheme through localized resonance in metallic nanoslits by light funneling. Angle insensitive colour filters up to ±80 degrees have been achieved, capable of wide colour tunability across the entire visible band with pixel size beyond the diffraction limit (~λ/2). This work opens the door to angle insensitive manipulation of light with structural filtering.

The interconversion of charge and spin currents via spin-Hall effect is essential for spintronics. Energy-efficient and deterministic switching of magnetization can be achieved when spin polarizations of these spin currents are collinear with the magnetization. However, symmetry conditions generally restrict spin polarizations to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced. Here, we show control of the spin polarization direction by using a non-collinear antiferromagnet Mn 3 GaN, in which the triangular spin structure creates a low magnetic symmetry while maintaining a high crystalline symmetry. We demonstrate that epitaxial Mn 3 GaN/permalloy heterostructures can generate unconventional spin-orbit torques at room temperature corresponding to out-of-plane and Dresselhaus-like spin polarizations which are forbidden in any sample with two-fold rotational symmetry. Our results demonstrate an approach based on spin-structure design for controlling spin-orbit torque, enabling high-efficient antiferromagnetic spintronics. In the typical spin-hall effect, spin-current, charge current, and spin polarisation are all mutually perpendicular, a feature enforced by symmetry. Here, using an anti-ferromagnet with a triangular spin structure, the authors demonstrate a spin-hall effect without a perpendicular spin alignment.

Optical multi-layer thin films are widely used in optical and energy applications requiring photonic designs. Engineers often design such structures based on their physical intuition. However, solely relying on human experts can be time-consuming and may lead to sub-optimal designs, especially when the design space is large. In this work, we frame the multi-layer optical design task as a sequence generation problem. A deep sequence generation network is proposed for efficiently generating optical layer sequences. We train the deep sequence generation network with proximal policy optimization to generate multi-layer structures with desired properties. The proposed method is applied to two energy applications. Our algorithm successfully discovered high-performance designs, outperforming structures designed by human experts in task 1, and a state-of-the-art memetic algorithm in task 2.