An AS-OCT image dataset for deep learning-enabled segmentation and 3D reconstruction for keratitis.

Infectious keratitis is among the major causes of global blindness. Anterior segment optical coherence tomography (AS-OCT) images allow the characterizing of cross-sectional structures in the cornea with keratitis thus revealing the severity of inflammation, and can also provide 360-degree information on anterior chambers. The development of image analysis methods for such cases, particularly deep learning methods, requires a large number of annotated images, but to date, there is no such open-access AS-OCT image repository. For this reason, this work provides a dataset containing a total of 1168 AS-OCT images of patients with keratitis, including 768 full-frame images (6 patients). Each image has associated segmentation labels for lesions and cornea, and also labels of iris for full-frame images. This study provides a great opportunity to advance the field of image analysis on AS-OCT images in both two-dimensional (2D) and three-dimensional (3D) and would aid in the development of artificial intelligence-based keratitis management.

Effect of Low-Temperature Plasma-Modified Carbon Fibers on Impact Load Damage of Low-Density Oil-Well Cement.

After large-scale exploitation of conventional oil and gas resources, most remaining resources are in highly depleted zones, where the fracture pressure of the formations is greatly reduced. Low-density oil-well cement prevents wellbore and formation fractures by reducing annular liquid column pressure and is one of the most commonly used cements in the oil and gas industry. However, cement sheaths made of low-density oil-well cement can be easily damaged due to the impact load generated during the well completion process. Incorporating carbon fibers into the cement matrix can effectively enhance the performance of cement sheaths. To ensure that carbon fibers can be closely combined with the cement matrix, low-temperature plasma modification technology was used in this study to pretreat the fibers. The mechanical properties of low-density oil-well cement incorporated with unmodified or modified carbon fibers were studied in detail under an impact load. The results of X-ray photoelectron spectroscopy revealed that the content of hydrophilic groups on the surface increased from 18.3 to 60.3% after the plasma treatment. The impact test results showed that the peak strengths of the cements cured at 60 °C for 14 days with 0.3% unmodified and modified carbon fibers could reach 37.01 ± 1.7 and 62.27 ± 1.7 MPa, respectively, under the impact load, i.e., an increase of 68.25% after the carbon fibers were treated with low-temperature plasma. Similarly, the absorbed energy increased from 15.59 to 44.31 J, and the energy absorption rate increased from 25.98 to 73.85%. Low-temperature plasma modification provided hydrophilic functional groups on the surface, significantly improving the interfacial bonding between the carbon fibers and cement matrix. The strengthened interaction was beneficial to extending the bearing time under the impact load and demonstrated a positive influence on the mechanical properties related to the impact resistance.

Multi-biomarker combination detection system for diagnosis and classification of dry eye disease by imaging of a multi-channel metasurface.

Dry eye disease (DED) is one of the most common ocular surface diseases, characterized by unstable tear film and ocular inflammation, affecting hundreds of millions of people worldwide. Currently, the clinical diagnosis of DED mainly relies on physical methods such as optical microscopy and ocular surface interferometric imaging, but classifying DED is still difficult. Here, we propose a compact and portable immune detection system based on the direct imaging of a nanophotonic metasurface with gradient geometry, for fast and ultra-sensitive detection of multiple biomarkers (i.e. Matrix metalloproteinase-9 (MMP-9), Lipocalin-1 (LCN-1), Lactoferrin (LTF)) in tears for the diagnosis and classification of DED. This centimeter-scale concentric nanophotonic metasurface, which consists of millions of unique metallic nanostructures, was fabricated through a cost-effective nanoimprint lithography (NIL) process. The immune detection system based on the antibody-modified metasurface shows favorable detection selectivity, an ultra-high sensitivity (3350 pixels/Refractive Index Unit (RIU)) and low limit of detection (LOD) (0.3 ng/mL for MMP-9, 1 ng/mL for LTF, and 0.5 ng/mL for LCN-1). Further clinical sampling and detection results demonstrated that this multi-biomarker detection system enabled accurate determination and symptom classification of DED, manifesting high correlation and consistency with clinical diagnosis results. The advantages such as low sample consumption, one-step detection, simple operation, and simultaneous detection of multiple biomarkers make the platform promising for screening and detecting a broader range of biomarker combinations in clinical practice.

Cost-Effective Nanophotonic Metasurfaces with Spatially Gradient Structures for Ultrasensitive Imaging-Based Refractometric Sensing.

Nanophotonic metasurfaces are widely utilized in various domains, such as biomedical, healthcare, and environmental monitoring, benefiting from their unique advantages of label-free, noninvasive, and real-time response. However, nanophotonic metasurfaces usually rely on sophisticated instruments, and expensive and time-consuming fabrication processes, which severely restricts their practical applications. Herein, a spatially gradient metasurface is integrated with an imaging-based sensing scheme, waiving the requirement of spectrometers and achieving an ultrahigh imaging-based sensitivity of 3321 pixels/refractive index unit superior to that characterized using conventional compact spectrometers. The metasurface is fabricated by nanoimprint lithography using a reusable cyclic olefin copolymer template featuring millions of unique nanostructures. Under the illumination of monochromatic light, the transmittance of different nanostructures on the metasurface differs, resulting in grayscale images with varied intensity distributions. Analyzing the intensity change of the metasurface's recorded image can obtain the covering medium's refractive index. Furthermore, through theory and experimentation, the high reliability of the proposed reusable and flexible template has been verified for nanophotonic metasurface fabrication which further reduces the fabrication cost of core sensing elements. Finally, with proper optimization of the metasurface structure and imaging system, this setup is expected to be applied to many emerging areas of point-of-care, real-time, and on-site biosensing.

Financial inclusion role on energy efficiency financing gaps in COVID-19 period: empirical outcomes of emerging nations.

The structural imposed crises of the COVID-19 have halted the system of financial intermediation at large. By this, the energy sector needs huge financing for energy efficiency maximization in the COVID-19 crises. Thus, the current research aims to inquire the role of financial inclusion in filling the energy efficiency financing gaps for the period of COVID-19 outbreak. The governments of many countries are facing fiscal deficits and trying to survive under tight substantial fiscal limitations. So providing a cheap and efficient energy in modern times, under COVID-19 crises, is merely impossible for many economies because the main source of income for energy sector is the energy users, and having inefficient energy for consumption is raising energy poverty at large. Therefore, COVID-19 crises raised a wide energy financing gap in modern times that needs a fix. However, this research is suggesting the system to make financial inclusion structure as effective, to fill the energy financing gap, for post-COVID-19 time, and to develop a viable and sustainable financing option for energy sector in long-run perspective. This study also validated the empirical role of financial inclusion on energy poverty and energy efficiency, with historical data, to justify the significance of financial inclusion for energy financing gap fulfillment. More so, this paper is also recommending new policy implications for the stakeholders to utilize. We believe if the recommended policy recommendations are considered for practice, the energy financing gap in post-COVID-19 era would be mitigated, and there is a high probability to supply the efficient energy to the end users.

Mechanical Properties of Calcium Aluminate Cement Reinforced with Plasma-Treated Basalt Fibers for In Situ Combustion.

Brittleness and poor tensile/flexural properties restrict the application of calcium aluminate cement (CAC) in oil and gas wells. Reinforcing CAC with fibers is an effective method for improving its strength and toughness and overcoming the shortcomings of its mechanical properties. In this article, as an auxiliary cementing material, slag does not affect the thickening time of CAC. After adding slag, the cement slurry meets the thickening time during cementing construction, and basalt fiber is selected as the toughening material. The enhancement effect of basalt fiber on the mechanical properties of CAC slag composites is studied, including the evaluation of the macroscopic mechanical properties and microstructure at a high temperature (500 °C). The optimum composition of basalt and fiber-reinforced CAC was determined. Basalt fibers were added to CAC at different contents of 0, 0.1, 0.2, 0.3, 0.4, and 0.5% based on the weight of the cement. All the results showed that the introduction of basalt fibers could significantly enhance the strength of the cement at high temperatures. Compared with the control samples, an additional increase in the compressive and tensile strengths of the samples of 35.1 and 85.2%, respectively, was achieved at high temperature with approximately 0.4% fiber content. Plasma treatment further improved the reinforcing effect of the basalt fibers, where the high-temperature compressive and tensile strengths of the samples increased from 28.88 and 1.52 to 35.23 and 1.87 MPa, respectively, an increase of 21.98 and 20.6%, respectively, compared with the untreated basalt fibers. When the cement paste is cured by simulated curing for 28 d, the high-temperature compressive strength and tensile strength with plasma modification increased from 28.26 and 1.5 to 29.1 and 2.15 MPa, respectively, an increase of 3.0 and 43.3%, respectively. The structure of the formed hydrates was studied using scanning electron microscopy. Furthermore, toughening of the basalt fiber-reinforced CAC-based composites resulted mainly from crack bridging and fiber pull-out.

High-fidelity and clean nanotransfer lithography using structure-embedded and electrostatic-adhesive carriers.

Metallic nanostructures are becoming increasingly important for both fundamental research and practical devices. Many emerging applications employing metallic nanostructures often involve unconventional substrates that are flexible or nonplanar, making direct lithographic fabrication very difficult. An alternative approach is to transfer prefabricated structures from a conventional substrate; however, it is still challenging to maintain high fidelity and a high yield in the transfer process. In this paper, we propose a high-fidelity, clean nanotransfer lithography method that addresses the above challenges by employing a polyvinyl acetate (PVA) film as the transferring carrier and promoting electrostatic adhesion through triboelectric charging. The PVA film embeds the transferred metallic nanostructures and maintains their spacing with a remarkably low variation of <1%. When separating the PVA film from the donor substrate, electrostatic charges are generated due to triboelectric charging and facilitate adhesion to the receiver substrate, resulting in a high large-area transfer yield of up to 99.93%. We successfully transferred the metallic structures of a variety of materials (Au, Cu, Pd, etc.) with different geometries with a <50-nm spacing, high aspect ratio (>2), and complex 3D structures. Moreover, the thin and flexible carrier film enables transfer on highly curved surfaces, such as a single-mode optical fiber with a curvature radius of 62.5 µm. With this strategy, we demonstrate the transfer of metallic nanostructures for a compact spectrometer with Cu nanogratings transferred on a convex lens and for surface-enhanced Raman spectroscopy (SERS) characterization on graphene with reliable responsiveness.

Resource Utilization of Red Mud from the Solid Waste of Aluminum Industry Used in Geothermal Wells.

It is difficult for the commonly used Class G oil well cement to withstand the high-temperature environment of geothermal wells, and it is easy to deteriorate the mechanical properties and damage the integrity of the cement sheath. Industrial solid waste red mud can be used as supplementary cementing materials (SCMs) to improve its mechanical properties at high temperatures. In addition, compared to Class G oil well cement, high belite cement (HBC) has lower energy consumption and better mechanical properties at high temperatures. In this study, the mechanical properties of HBC as a gel material and quartz sand and red mud as SCMs were studied at high temperatures. The ratio of HBC to SCMs and the ratio of quartz sand to red mud in SCMs were optimized using the response surface method (RSM). The response surface was established using the three-level factorial design model, which fit well with the experimental data. The optimization results show that the best mass ratio of SCMs/HBC is 37.5% and that the best quality ratio of quartz sand/red mud is 9 under the curing conditions of 180 °C. However, the best mass ratio of SCMs/HBC is 49.3%, and the best quality ratio of quartz sand/red mud is 7 under 220 °C. With the addition of SCMs, the silicon-to-calcium ratio of HBC hydration products decreases, and high-temperature-stable xonotlite and tobermorite can be formed. After adding SCMs, the cement sample is denser without obvious cracks.

Hybrid modeling of perovskite light-emitting diodes with nanostructured emissive layers.

Perovskite light-emitting diodes (PeLEDs) have attracted much attention due to their superior performance. When a bottleneck of energy conversion efficiency is achieved with materials engineering, nanostructure incorporation proves to be a feasible approach to further improve device efficiencies via light extraction enhancement. The finite-difference time-domain simulation is widely used for optical analysis of nanostructured optoelectronic devices, but reliable modeling of PeLEDs with nanostructured emissive layers remains unmet due to the difficulty of locating dipole light sources. Herein we established a hybrid process for modeling light emission behaviors of such nanostructured PeLEDs by calibrating light source distribution through electrical simulations. This hybrid modeling method serves as a universal tool for structure optimization of light-emitting diodes with nanostructured emissive layers.

Ultrasensitive Molecular Detection at Subpicomolar Concentrations by the Diffraction Pattern Imaging with Plasmonic Metasurfaces and Convex Holographic Gratings.

Compact and cost-effective optical devices for highly sensitive detection of trace molecules are significant in many applications, including healthcare, pollutant monitoring and explosive detection. Nanophotonic metasurface-based sensors have been intensively attracting attentions for molecular detection. However, conventional methods often involve spectroscopic characterizations that require bulky, expensive and sophisticated spectrometers. Here, a novel ultrasensitive sensor of plasmonic metasurfaces is designed and fabricated for the detection of trace molecules. The sensor features a convex holographic grating, of which the first-order diffraction pattern of a disposable metasurface is recorded by a monochrome camera.The diffraction pattern changes with the molecules attached to the metasurface, realizing label-free and spectrometer-free molecular detection by imaging and analyzing of the diffraction pattern. By integrating the sensor with a microfluidic setup, the quantitative characterization of rabbit anti-human Immunoglobulin G (IgG) and human IgG biomolecular interactions is demonstrated with an excellent limit of detection (LOD) of 0.6 pm. Moreover, both the metasurface and holographic grating are obtained through vacuum-free solution-processed fabrications, minimizing the manufacturing cost of the sensor. A prototype of the imaging-based sensor, consisting of a white light-emitting diode (LED) and a consumer-level imaging sensor is achieved to demonstrate the potential for on-site detection.

Mechanical Properties of Graphite-Oil Well Cement Composites under High Temperature.

Under the condition of heavy oil thermal recovery, the cement sheath is easy to crack in the high temperature environment, resulting in the decrease of cement paste strength, which may further cause sealing failure and oil and gas production safety accidents. In this paper, the influence of graphite on the mechanical properties of cement paste under the simulated thermal recovery of heavy oil was studied, and its mechanism is explored by testing and analyzing the microstructure. The phase composition and microstructure of graphite-cement composites were determined by X-ray diffraction analysis (XRD) and scanning electron microscope (SEM), and the thermogravimetric analyzer (TG/DTG) was used to analyze the heat resistance of the graphite-cement composites. The results show that the addition of graphite significantly improved the strength and deformation resistance of the Class G oil well cement at high temperature (300, 400, and 500 °C) and low temperature (50 °C), and the optimal addition amount is 0.07%. The microscopic analysis shows that the incorporation of graphite promoted the formation of hydration products, and played a role in filling pores and reducing microcracks in cement pastes. At the same time, due to the better thermal conductivity of graphite, it can balance the internal thermal stress of the cement pastes and inhibit the strength decline of cement pastes under high temperature environments. The integrity of cement pastes was guaranteed through the mechanism of "crack deflection" and "crack bridging". The research results of this paper have presented a certain theoretical basis and new ideas for the development of cementing slurry systems in heavy oil thermal recovery wells.

Intelligent and highly sensitive strain sensor based on indium tin oxide micromesh with a high crack density.

Cracks play an important role in strain sensors. However, a systematic analysis of how cracks influence the strain sensors has not been proposed. In this work, an intelligent and highly sensitive strain sensor based on indium tin oxide (ITO)/polyurethane (PU) micromesh is realized. The micromesh has good skin compatibility, water vapor permeability, and stability. Due to the color of the ITO/PU micromesh, it can be invisible on the skin. Based on the fragility of ITO, the density and resistance of cracks in the micromesh are greatly improved. Therefore, the ITO/PU micromesh strain sensor (IMSS) has an ultrahigh gauge factor (744.3). In addition, a finite element model based on four resistance layers is proposed to explain the performance of the IMSS and show the importance of high-density cracks. Compared with other strain sensors based on low-density cracks, the IMSS based on high-density cracks has larger sensitivity and better linearity. Physiological signals, such as respiration, pulse, and joint motion, can be monitored using the IMSS self-fixed on the skin. Finally, an invisible and artificial throat has been realized by combining the IMSS with a convolutional neural network algorithm. The artificial throat can translate the throat vibrations of the tester automatically with an accuracy of 86.5%. This work has great potential in health care and language function reconstruction.

LncRNA ubiquitin-binding protein domain protein 10 antisense RNA 1 inhibits colon adenocarcinoma progression via the miR-515-5p/slit guidance ligand 3 axis.

Dysregulated long non-coding RNAs (lncRNAs) play an important role in cancer progression. However, there have been limited reports to date of the involvement of ubiquitin-binding protein domain protein 10 antisense RNA 1 (UBXN10-AS1) in cancer. Our aim was to explore the role and underlying mechanism of UBXN10-AS1 in the occurrence of colon adenocarcinoma (COAD). Real-time quantitative PCR and Western blotting were performed to determine the expression of UBXN10-AS1, miR-515-5p, and Slit guidance ligand 3 (SLIT3). Cell Counting Kit-8 and wound healing scratch assays were performed to measure COAD cell proliferation and migration. A xenograft assay was performed to examine tumor growth in vivo. Luciferase reporter and RNA immunoprecipitation (RIP) assays were used to determine the binding interaction among miR-515-5p, UBXN10-AS1, and SLIT3. The results showed that UBXN10-AS1 and SLIT3 were expressed at low levels in COAD tissues, while miR-515-5p was expressed at high levels. UBXN10-AS1 overexpression suppressed tumor growth in vitro and in vivo. The luciferase reporter and RNA RIP assays demonstrated that UBXN10-AS1 targeted miR-515-5p, which in turn targeted SLIT3. Functionally, miR-515-5p overexpression reversed the inhibition of COAD cell proliferation and migration by UBXN10-AS1 overexpression, and SLIT3 overexpression counteracted the oncogenicity of miR-515-5p. Our study shows that UBXN10-AS1 modulates the miR-515-5p/SLIT3 axis, thereby resulting in the inhibition of COAD cell proliferation and migration.

Ultrasensitive Molecular Detection by Imaging of Centimeter-Scale Metasurfaces with a Deterministic Gradient Geometry.

Highly sensitive detection of trace amounts of substances is crucial for broad applications in healthcare, environmental monitoring, antiterrorism, etc., where cost effectiveness and portability are often demanded. Here, an ultrasensitive sensor is reported that can detect an angstrom-thick layer of adsorbed molecules through image acquisition and processing. The sensor features a centimeter-scale plasmonic metasurface with spatially varying geometry, where the light scattering is dependent on both the adsorbed substances and spatial locations. When illuminated with narrowband light (such as from a light emitting diode), the intensity pattern recorded on the metasurface changes with the surface-adsorbed molecules, enabling label-free, sensitive, and spectrometer-free molecular detection. The centimeter-scale size of the sensing area interfaces well with consumer-level imaging sensors on mobile devices without the need for microscopic optics and offers a high signal-to-noise ratio by leveraging the multimillion pixels for noise reduction. It is experimentally demonstrated that a single layer of Al2 O3 molecules deposited on the sensor, with a thickness of approximately one angstrom, can be detected by analyzing the images taken of the sensing chip. Furthermore, by integrating the sensor into a microfluidic setup, quantitative detection of BSA/anti-BSA immune complex formation events is demonstrated, which agrees well with the Langmuir isotherm model.

Cyhalofop-butyl and Glyphosate Multiple-Herbicide Resistance Evolved in an Eleusine indica Population Collected in Chinese Direct-Seeding Rice.

Eleusine indica is a typical xerophytic weed species with a cosmopolitan distribution. It is invasive and highly adaptable to diverse habitats and crops. Due to rice cropping-pattern changes, E indica has become one of the main dominant grass weeds infecting direct-seeding paddy fields. A Chinese E. indica population has evolved multiple-herbicide resistance to cyhalofop-butyl and glyphosate. In this study, the multiple-resistance profile of E. indica to these two different types of herbicides and their resistance mechanisms were investigated. Whole-plant dose-response assays indicated that the multiple-herbicide-resistant (MHR) population exhibited 10.8-fold resistance to cyhalofop-butyl and 3.1-fold resistance to glyphosate compared with the susceptible (S) population. ACCase sequencing revealed that the Asp-2078-Gly mutation was strongly associated with E. indica resistance to cyhalofop-butyl. The MHR plants accumulated less shikimic acid than S plants at 4, 6, and 8 days after glyphosate treatment. In addition, no amino acid substitution in the EPSPS gene was found in MHR plants. Further analysis revealed that the relative expression level of EPSPS in MHR plants was 6-10-fold higher than that in S plants following glyphosate treatment, indicating that EPSPS overexpression may contribute to the glyphosate resistance. Furthermore, the effectiveness of nine post-emergence herbicides against E. indica were evaluated, and one PPO inhibitor pyraclonil was identified as highly effective in controlling the S and MHR E. indica populations.

Molecular basis of resistance to ACCase-inhibiting herbicide cyhalofop-butyl in Chinese sprangletop (Leptochloa chinensis (L.) Nees) from China.

Chinese sprangletop (Leptochloa chinensis (L.) Nees) is one of the most troublesome grass weeds in rice in China. Seven suspected cyhalofop-butyl-resistant L. chinensis populations were collected from different rice fields with a history of cyhalofop-butyl use. The level of resistance and resistance mechanisms in seven populations were studied. Dose-response tests indicated that five populations (JS3, JS4, JS6, JS7 and JS8) had evolved high-level resistance (26.9 to 123.0-fold) to cyhalofop-butyl compared with the susceptible (S) population, and other two populations (JS2 and JS5) were still sensitive to the herbicide. Two acetyl-coenzyme A carboxylase (ACCase) genes were cloned from each population, and three different ACCase mutations (Ile-1781-Leu, Trp-1999-Cys, and Trp-2027-Cys) in ACCase2 gene were determined in different resistant (R) populations. In addition, no resistance-conferring mutations was detected in the R population (JS7), and ACCase gene expression was similar between the S and R populations. Thus, non-target-site resistance mechanisms may be involved in the JS7 population. Moreover, the patterns of cross-resistance of JS6 (Ile-1781-Leu), JS4 (Trp-1999-Cys), JS8 (Trp-2027-Cys), and JS7 (unknown resistance mechanisms) populations to other ACCase-inhibiting herbicides were determined. The JS6 and JS8 populations showed resistance to fenoxaprop-P-ethyl, metamifop, clethodim and pinoxaden, the JS4 population was resistant to fenoxaprop-P-ethyl, metamifop and pinoxaden, and the JS7 population had resistance only to fenoxaprop-P-ethyl and metamifop. These results indicated the diversity of the target-site mutations in ACCase gene of L. chinensis, and provide a better understanding of cross-resistance in L. chinensis, which would be helpful for the management of cyhalofop-butyl-resistant L. chinensis.

Selective Electroless Metallization of Micro- and Nanopatterns via Poly(dopamine) Modification and Palladium Nanoparticle Catalysis for Flexible and Stretchable Electronic Applications.

The authors report a new patterned electroless metallization process for creating micro- and nanoscale metallic structures on polymeric substrates, which are essential for emerging flexible and stretchable optical and electronic applications. This novel process features a selective adsorption of catalytic Pd nanoparticles (PdNPs) on a lithographically masked poly(dopamine) (PDA) interlayer in situ polymerized on the substrates. The moisture-resistant PDA layer has excellent stability under a harsh electroless plating bath, which enables electroless metallization on versatile substrate materials regardless of their hydrophobicity, and significantly strengthens the attachment of electroless plated metallic structures on the polymeric substrates. Prototype devices fabricated using this PDA-assisted electroless metallization patterning exhibit superior mechanical stability under high bending and stretching stress. The lithographic patterning of the PDA spatially confines the adsorption of PdNPs and reduces defects due to random adsorption of catalytic particles on the undesired area. The high resolution of the lithographic patterning enables the demonstration of a copper micrograting pattern with a linewidth down to 2 µm and a silver plasmonic nanodisk array with a 500 nm pitch. A copper mesh is also fabricated using our new patterned electroless metallization process and functions as flexible transparent electrodes with >80% visible transmittance and <1 Ω sq-1 sheet resistance. Moreover, flexible and stretchable dynamic electroluminescent displays and functional flexible printed circuits are demonstrated to show the promising capability of our fabrication process in versatile flexible and stretchable electronic devices.

Top-down fabrication of shape-controlled, monodisperse nanoparticles for biomedical applications.

Nanoparticles for biomedical applications are generally formed by bottom-up approaches such as self-assembly, emulsification and precipitation. But these methods usually have critical limitations in fabrication of nanoparticles with controllable morphologies and monodispersed size. Compared with bottom-up methods, top-down nanofabrication techniques offer advantages of high fidelity and high controllability. This review focuses on top-down nanofabrication techniques for engineering particles along with their biomedical applications. We present several commonly used top-down nanofabrication techniques that have the potential to fabricate nanoparticles, including photolithography, interference lithography, electron beam lithography, mold-based lithography (nanoimprint lithography and soft lithography), nanostencil lithography, and nanosphere lithography. Varieties of current and emerging applications are also covered: (i) targeting, (ii) drug and gene delivery, (iii) imaging, and (iv) therapy. Finally, a future perspective of the nanoparticles fabricated by the top-down techniques in biomedicine is also addressed.

Stretchable Transparent Electrodes with Solution-Processed Regular Metal Mesh for an Electroluminescent Light-Emitting Film.

We report stretchable metal-mesh transparent electrodes (TEs) with excellent electrical conductivity (<2 Ω/sq) and optical transparency (>80%) under up to 55% strain. The figures of merit on these electrodes, as defined as the ratio between electrical conductivity and optical conductivity, are among the highest reported for stretchable TEs under moderate stretching. Moreover, we demonstrate their application in a stretchable electroluminescent (EL) light-emitting film as top and bottom electrodes. EL lighting devices require low-resistance electrodes to unleash their potential for large-area low-power-consumption applications, in which our highly conductive and transparent stretchable TEs provide an edge on other competitor approaches. Importantly, our stretchable metal-mesh electrodes are fabricated through a vacuum-free solution-processed approach that is scalable for cost-effective mass production. We also investigate the fracture and fatigue mechanisms of stretchable metal-mesh electrodes with various mesh patterns and observe different behaviors under one-time and cyclic stretching conditions. Our solution-processed fabrication method, failure mechanism investigation, and device demonstration for metal-mesh stretchable TEs will facilitate the adoption of this promising high-performance approach in stretchable and wearable electronics applications.

Wafer-scale nanopatterning using fast-reconfigurable and actively-stabilized two-beam fiber-optic interference lithography.

A fast-reconfigurable and actively-stabilized fiber-optic interference lithography system is demonstrated in this paper. Employment of fiber-optic components greatly enhances the flexibility of the whole system, simplifies its optical alignment, and suppresses the interference of mechanical vibrations. Active stabilization is implemented in the system and evaluated through modeling and experiment. We demonstrate 3-inch-diameter wafer-scale patterning of 240-nm-period grating lines with a sub-50-nm linewidth and an aspect ratio over 3. Two-dimensional patterns of different geometries and dimensions are also demonstrated to show the versatility of our system. Step-and-repeat exposure is demonstrated with independently controlled patterning fields of 2×2cm2 large.