Search

Wearable piezoresistive sensors have aroused considerable attention for their huge potential in emerging applications such as healthcare monitoring and intelligent electronics. However, the fabrication of piezoresistive sensors that combine excellent sensing performance with outstanding working reliability in watery environments still remains challenging. Herein, a superhydrophobic polyurethane (PU) sponge was proposed as a piezoresistive sensor through the synthesis of d-asparagine-modified MXene nanosheets (MXene-NH2) and coating of a conductive cross-linkable layer constructed by dihydroxyl-terminated poly-(dimethylsiloxane) (PDMS-(OH)) and MXene-NH2 nanosheets. The microscale sponge skeleton and nanoscale PDMS-MXene nanosheet wrinkles formed a hierarchically rough structure in support of superhydrophobicity with a water contact angle of 160°. Benefiting from the chemically cross-linkable network and strong adhesion of PDMS-MXene nanosheet coating, the obtained PDMS-MXene@PU sponge exhibited a robust water repellency with water contact angles (WCAs) larger than 150° after enduring chemical and physical damages. Owing to the synergistic effect of the production of microcrack junctions in the PDMS-MXene nanosheet layer and contact separation between conductive backbones, the PDMS-MXene@PU sensor was successfully applied in monitoring full-scale human motions (e.g., blowing, facial expression, finger and knee bending, etc.) with excellent sensing performances of the gauge factor reaching −1.9. The findings conceivably stand out as a methodology to fabricate robust superhydrophobic piezoresistive sensors with desirable sensing property for innovative and broad applications even under special working conditions. [ABSTRACT FROM AUTHOR]

Recently, the membrane separation materials show promising applications in the fields of crude oil removal because of their low energy consumption and less secondary pollution. However, the membrane separation materials suffer problem of low separation efficiency due to the high viscosity of crude oil. Here, a superhydrophobic material with Joule heat and photothermal effect was prepared by decorating the delignified wood with reduced graphene oxide (GSH) and vinyl terminated polydimethylsiloxane (V-PDMS) through thiol-ene click reaction. The prepared PDMS@GSH wood exhibited stable superhydrophobicity with a water contact angle of 156°. Meanwhile, the GSH layer provided promising electrothermal effect that endowed the PDMS@GSH wood with excellent crude oil/water separation capability under the Joule heat with a surface temperature of 139 °C and separation rate of 1.78 × 105 kg m−3 h−1. Besides, the PDMS@GSH wood displayed a good photothermal effect that assisted with the Joule heat to heat the wood for crude oil removal to save energy. More importantly, the PDMS was crosslinked with GSH on the wood via thiol-ene click reaction, leading to the stable superhydrophobicity and electrical conductivity in strong acid or alkali environment. This material has broad application prospects in crude oil clean-up due to its high separation speed and easy large-scale production. [Display omitted] • A new strategy for fabricating superhydrophobic wood with heating property is proposed. • The wood presents stable superhydrophobicity and electrical conductivity. • The wood shows excellent Joule heat and photothermal effect. • The wood exhibits high separation rate for viscous crude oil wastewater. [ABSTRACT FROM AUTHOR]

Layout hotspot detection is one of the most important issues for the reliability enhancement of integrated circuits. Machine learning-based hotspot detectors have shown their advantages of efficiency and generalization compared with computationally intensive lithography process simulation. However, most machine learning-based hotspot detectors only accept layout clips of fixed size as input with the potential defect whose location is restricted at the center of each clip. Therefore, they cannot be used directly for multiple hotspots detection in a large area, which occurs frequently in real design cases. In this article, we build a new end-to-end hotspot detector based on a fully convolutional network, which has the flexibility of detecting a various number of hotspots in a layout of any size at one time. Moreover, we also develop a transfer learning scheme matching our proposed detector network, which can reduce the requirement of sample number when setting up a new model for a more advanced technology node. The experimental results demonstrate our proposed hotspot detector outstanding among state-of-the-art works and the transfer learning scheme is effective. [ABSTRACT FROM AUTHOR]

Streptococcus pyogenes is a major human-specific bacterial pathogen and a common cause of a wide range of symptoms from mild infection such as pharyngitis (commonly called strep throat) to life-threatening invasive infection and post-infectious sequelae. Traditional methods for diagnosis include collecting a sample using a pharyngeal swab, which can cause discomfort and even discourage adults and children from seeking proper testing and treatment in the clinic. Saliva samples are an alternative to pharyngeal swabs. To improve the testing experience for strep throat, we developed a novel lollipop-inspired sampling platform (called CandyCollect) to capture bacteria in saliva. The device can be used in clinics or in the home and shipped back to a lab for analysis, integrating with telemedicine. CandyCollect is designed to capture bacteria on an oxygen plasma treated polystyrene surface embedded with flavoring substances to enhance the experience for children and inform the required time to complete the sampling process. In addition, the open channel structure prevents the tongue from scraping and removing the captured bacteria. The flavoring substances did not affect bacterial capture and the device has a shelf life of at least 2 months (with experiments ongoing to extend the shelf life). We performed a usability study with 17 participants who provided feedback on the device design and the dissolving time of the candy. This technology and advanced processing techniques, including polymerase chain reaction (PCR), will enable user-friendly and effective diagnosis of streptococcal pharyngitis. [ABSTRACT FROM AUTHOR]

Open microfluidic cell culture systems are powerful tools for interrogating biological mechanisms. We have previously presented a microscale cell culture system, based on spontaneous capillary flow of biocompatible hydrogels, that is integrated into a standard cell culture well plate, with flexible cell compartment geometries and easy pipet access. Here, we present two new injection molded open microfluidic devices that also easily insert into standard cell culture well plates and standard culture workflows, allowing seamless adoption by biomedical researchers. These platforms allow culture and study of soluble factor communication among multiple cell types, and the microscale dimensions are well-suited for rare primary cells. Unique advances include optimized evaporation control within the well, manufacture with reproducible and cost-effective rapid injection molding, and compatibility with sample preparation workflows for high resolution microscopy (following well-established coverslip mounting procedures). In this work, we present several use cases that highlight the usability and widespread utility of our platform including culture of limited primary testis cells from surgical patients, microscopy readouts including immunocytochemistry and single molecule fluorescence in situ hybridization (smFISH), and coculture to study interactions between adipocytes and prostate cancer cells. [ABSTRACT FROM AUTHOR]

As an approach of resolution enhancement technique (RET), sub-resolution assist feature (SRAF) is used to meet the pitch requirements for sparse patterns in off-axis illumination (OAI) and supplements the spatial frequencies of main patterns to improve the resolution. Rules-based SRAF (RB-SRAF) is a technique that foundry extracts SRAF placement rules from wafer data or simulation data and then apply these rules to full chip. RB-SRAF often produces a lot of conflicts. Usually, the geometric constrains are the only factors taken into account in cleaning up of these conflicts, which may lead to mistaken cleanup and be counter-productive. Therefore, it is necessary to introduce some physical factors in the course of cleanup. The transmissivity distribution of mask in hotspot region can be obtained by inverse lithography technology (ILT). And the statistical information of the grayscale map from ILT can be used for leading cleanup and keeping the SRAFs which contribute more to process window (PW). The feasibility of this method has been verified by a series of simulations. [ABSTRACT FROM AUTHOR]

The fabrication of functional superhydrophobic surfaces that combine various performances for the emerging application horizons such as deicing and self-propelled machines remains challenging. In the present work, a vacuum-assisted layer-by-layer superhydrophobic carbon nanotube film integrating the electrothermal effect with photothermal performance was fabricated by vacuum-assembling a multilayer of carboxylated and aminated multiwalled carbon nanotubes ((MWCNTs-COOH/MWCNTs-NH2)n), followed by transferring onto a desired substrate coated with an ethylene-vinyl acetate (EVA) copolymer and modifying with n-octadecylamine (ODA) through the amidation reaction. Using a filtration membrane as a template, the multiwalled carbon nanotube (MWCNT) film displayed micro–nano hierarchical roughness in support of superhydrophobicity with a CA of 165°. Importantly, the MWCNT film also served as a functional heater under an applied voltage or different light sources. Utilizing the electrothermal effect and water repellency, the superhydrophobic MWCNT film was successfully applied in high-speed deicing. Additionally, combining the surface tension gradients generated by photothermal performance with reduced drag on the water surface, the superhydrophobic MWCNT film was propelled to move linearly, curvilinearly, and rotationally. These findings conceivably stand out as a new tool to fabricate functional superhydrophobic films with electrothermal and photothermal effects for various potential applications. [ABSTRACT FROM AUTHOR]

Precise detection of a nanometer-scale pattern's edge positions in an SEM image is challenging for next generation patterning technology development. Here, two different edge detection methods are proposed: one is based on a normal method employing the edge threshold algorithm and the other is based on a cross-correlation method by calculating the real image with a reference. Line/space and circle pattern types are both studied and compared with the two methods. By using different SEM images without noise and with noise, the pros and cons of the abovementioned two methods are summarized. With the implementation of the power spectral density method, the comparison shows that the cross-correlation method suppresses the metrology uncertainty of edge positions and edge roughness. Besides, the cross-correlation method also calculates all potential edge defects, especially the footing defects and the top loss defects. The method has high application potential in the 3D reconstruction process by using different reference waves; in addition to this, it enables novel focus-energy-matrix (FEM) metrology such as the roughness FEM and defect FEM. [ABSTRACT FROM AUTHOR]

Microscale cell-based assays have demonstrated unique capabilities in reproducing important cellular behaviors for diagnostics and basic biological research. As these assays move beyond the prototyping stage and into biological and clinical research environments, there is a need to produce microscale culture platforms more rapidly, cost-effectively, and reproducibly. ‘Rapid’ injection molding is poised to meet this need as it enables some of the benefits of traditional high volume injection molding at a fraction of the cost. However, rapid injection molding has limitations due to the material and methods used for mold fabrication. Here, we characterize advantages and limitations of rapid injection molding for microfluidic device fabrication through measurement of key features for cell culture applications including channel geometry, feature consistency, floor thickness, and surface polishing. We demonstrate phase contrast and fluorescence imaging of cells grown in rapid injection molded devices and provide design recommendations to successfully utilize rapid injection molding methods for microscale cell-based assay development in academic laboratory settings. [ABSTRACT FROM AUTHOR]

Cellular communication between multiple cell types is a ubiquitous process that is responsible for vital physiological responses observed in vivo (e.g., immune response, organ function). Many in vitro coculture strategies have been developed, both in traditional culture and microscale systems, and have shown the potential to recreate some of the physiological behaviors of organs or groups of cells. A fundamental limitation of current systems is the difficulty of reconciling the additional engineering requirements for creating soluble factor signaling systems (e.g., segregated cell culture) with the use of well-characterized materials and platforms that have demonstrated successful results and biocompatibility in assays. We present a new open-microfluidic platform, the Monorail Device, that is placed in any existing well plate or Petri dish and enables patterning of segregated coculture regions, thereby allowing the direct upgrade of monoculture experiments into multiculture assays. Our platform patterns biocompatible hydrogel walls via microfluidic spontaneous capillary flow (SCF) along a rail insert set inside commercially available cultureware, creating customized pipette-accessible cell culture chambers that require fewer cells than standard macroscale culture. Importantly, the device allows the use of native surfaces without additional modification or treatments, while creating permeable dividers for the diffusion of soluble factors. Additionally, the ease of patterning afforded by our platform makes reconfiguration of the culture region as simple as changing the rail insert. We demonstrate the ability of the device to pattern flows on a variety of cell culture surfaces and create hydrogel walls in complex and precise shapes. We characterize the physical parameters that enable a reproducible SCF-driven flow and highlight specialized design features that increase the ease of use of the device and control of the open microfluidic flow. Further, we present the performance of our platform according to useful coculture criteria, including permeability and integrity of our hydrogel walls and surface-sensitive cell culture. Lastly, we show the potential of this type of platform to create modular multikingdom culture systems that can be used to study soluble factor signaling between mammalian cells, bacteria, and fungi, as well as the potential for adaptation of this technology by researchers across multiple fields. [ABSTRACT FROM AUTHOR]

Sauerkraut is a Chinese traditional fermented vegetable product. However, excessive nitrite in sauerkraut may cause food safety problems. This study screened three highly-efficient nitrite-degrading lactobacilli, namely, B1, C1 and D2, with over 75% degradation rate. According to the morphology, physiological and biochemical characteristics, as well as the 16S rDNA analysis, we found that B1 belonged to Lactobacillus pentosus, whereas C1 and D2 belonged to Lactobacillus plantarum. After ultraviolet (UV)-nitrosoguanidine compound mutation, the degradation rates of the three lactobacilli to nitrite improved by 5.8, 8.0 and 12.7%, respectively. After the acclimation of sauerkraut juice with 80% concentration, single lactobacillus and mixed lactobacilli were applied in the sauerkraut product. The results indicated that the degradation effects of mixed strains on nitrite were better than that of single one. Compared with the control group (0-36.6 mg/kg), the mixed strains inoculated in the early fermentation period can significantly decrease the nitrite residue in sauerkraut (0-20.8 mg/kg) and the fermentation period can be shortened from 30 to 20 days. The sauerkraut produced showed good quality and flavor. Therefore, this study has significant application value for industrial production of sauerkraut. Practical Applications Nitrite formed in traditional fermented sauerkraut is an unsolved safety problem. This study screened three highly-efficient nitrite-degrading lactobacilli strains. After ultraviolet (UV)-nitrosoguanidine compound mutation, the degradation rates of the three lactobacilli to nitrite were over 81.5%. Compared with the control group (36.6 mg/kg), the mixed strains inoculated in the early fermentation period could significantly decrease the nitrite residue in sauerkraut (20.8 mg/kg) and the fermentation period could be shortened from 30 to 20 days. Therefore, this study has significant application value for the industrial production of sauerkraut. [ABSTRACT FROM AUTHOR]