Wearable sweat sensors have the potential to provide continuous measurements of useful biomarkers. However, current sensors cannot accurately detect low analyte concentrations, lack multimodal sensing or are difficult to fabricate at large scale. We report an entirely laser-engraved sensor for simultaneous sweat sampling, chemical sensing and vital-sign monitoring. We demonstrate continuous detection of temperature, respiration rate and low concentrations of uric acid and tyrosine, analytes associated with diseases such as gout and metabolic disorders. We test the performance of the device in both physically trained and untrained subjects under exercise and after a protein-rich diet. We also evaluate its utility for gout monitoring in patients and healthy controls through a purine-rich meal challenge. Levels of uric acid in sweat were higher in patients with gout than in healthy individuals, and a similar trend was observed in serum.
Concerns regarding microplastic contamination have spread from aquatic environments to terrestrial systems with a growing number of studies have been reported. Notwithstanding, the potential effects on soil ecosystems remain largely unexplored. In this study, the effects of polyethylene microplastics on soil enzymatic activities and the bacterial community were evaluated, and the microbiota colonizing on microplastics were also investigated. Microplastic amendment (2000 fragments per kg soil) significantly increased the urease and catalase activities in soil after 15 days, and no discernible alteration of invertase activities was detected. Results from high-throughput sequencing of 16S rRNA revealed that the alpha diversities (richness, evenness, and diversity) of the microbiota in soil were not obviously changed by the PE amendment, whereas the diversity indexes of microbiota on plastic fragments were significantly lower than those in the control and amended soils. Different taxonomic composition was observed in between the control and amended soils after 90 days of incubation. Bacterial assemblages with distinct community structure colonized the PE microplastics. Additionally, several taxa including plastic- degrading bacteria and pathogens were more abundant on microplastics. Simultaneously, the pre- dicted functional profiles showed that the pathways of amino acid metabolism and xenobiotics biodegradation and metabolism were higher on the microplastics. These results indicated that micro- plastics in soil, compared with those in aquatic environments, can also act as a distinct microbial habitat, potentially altering the ecological functions of soil ecosystems. 
In low-pressure-turbines (LPT) around 60-70% of losses are generated away from end-walls, while the remaining 30-40% is controlled by the interaction of the blade profile with the endwall boundary layer. Experimental and numerical studies have shown how the strength and penetration of the secondary flow depends on the characteristics of the incoming end-wall boundary layer. This paper discusses the endwall flow characteristics of the T106 LPT profile at Re=120K and M=0.59 by benchmarking with experiments and investigating the impact of the incoming boundary layer state. The simulations are carried out with proven Reynolds-averaged Navier–Stokes (RANS) and large-eddy simulation (LES) solvers to determine if Reynolds Averaged models can capture the relevant flow details with enough accuracy to drive the design of this flow region. Part I of the paper focuses on the critical grid needs to ensure accurate LES, and on the analysis of the overall time averaged flow field and comparison between RANS, LES, and measurements when available. In particular, the growth of secondary flow features, the trace and strength of the secondary vortex system, its impact on the blade load variation along the span and end-wall flow visualizations are analyzed. The ability of LES and RANS to accurately predict the secondary flows is discussed together with the implications this has on design.
Organic-inorganic metal halide perovskites have drawn a great deal of attention due to their supreme optical and electrical properties and their potential in future application in optoelectronic devices. Here, we carry out finite-difference time-domain (FDTD) simulation on different experimentally realistic structures of perovskite solar cells (PSC) and optimize their parameters with assistance of neural network (NN). We find an optimized structure with 30.48% enhancement comparing to planar structure and the fact that with properly design, 300-nm-thick nano-textured structure can outperform 900-nm-thick planar structure. We believe that light trapping structure is essential in thin film PSCs and also has a great potential in lead-free PSCs.
Fluorescent nanoprobes are indispensable tools to monitor and analyze biological species and dynamic biochemical processes in cells and living bodies. Conventional nanoprobes have limitations in obtaining imaging signals with high precision and resolution because of the interference with biological autofluorescence, off-target effects, and lack of spatiotemporal control. As a newly developed paradigm, light-activated nanoprobes, whose imaging and sensing activity can be remotely regulated with light irradiation, show good potential to overcome these limitations. Herein, recent research progress on the design and construction of light-activated nanoprobes to improve bioimaging and sensing performance in complex biological systems is introduced. First, recent innovative strategies and their underlying mechanisms for light-controlled imaging are reviewed, including photoswitchable nanoprobes and phototargeted nanosystems. Subsequently, a short highlight is provided on the development of light-activatable nanoprobes for biosensing, which offer possibilities for the remote control of biorecognition and sensing activity in a precise manner both temporally and spatially. Finally, perspectives and challenges in light-activated nanoprobes are commented.
Abstract A novel pattern strategy of a nanomaterial network that can self-assemble onto prepatterned soft substrate to realize ultra-transparent electronics is presented. The approach detailed is based on the combination of nanomaterials' self-assembly at the water–air interface to form nanomaterial networks and the breakage phenomenon of water–nanomaterial membranes to form designed patterns. With the comprehensive investigation of this phenomenon, nanomaterial networks are manipulated to attach to prepatterned sidewalls. This leads to a remarkable transparency improvement without conductive property decline. Three 1D nanomaterials with various geometries are demonstrated to verify the universal feature of this pattern strategy, including silver nanowire (AgNW), carbon nanotube, and zinc oxide nanowire. Furthermore, sequential layer-by-layer deposition of several 1D nanomaterials has also been demonstrated by using the proposed approach, revealing an attractive potential of multiple-junction transparent electronics. The fabricated micro-grid structure of AgNWs with a line width of 5 µm and pitch of 150 µm has a sheet resistance of 37.88 Ω sq−1 and an optical transmittance of 86.06%. This fabrication strategy opens up opportunities for different nanomaterials in many transparent and wearable applications.
Stretchable electronics have great importance in the application of wearable device and electronic skin. The balance and improvements of mechanical stretchability and electronic performance are the great challenges that restrict the further development of stretchable electronics. In order to achieve stretchable electronics, it is crucial to choose the proper substrates, among which PDMS is the most commonly used polymer due its easy fabrication and low cost. In this paper, we propose a novel strategy and fabricate localized and precise modulus-controlled PDMS for both two/three-dimensional stretchable electronics. Based on a secondary cross-link effect, the modulus of cured PDMS can be enhanced and precisely controlled by spin-coating different mass of curing agent. Using laser-cutted PI mask, the modulus-enhanced region can be defined by users. Through this simple method, the functional conductive thin-film materials (Gold/Ag nanowires/Reduced Graphene oxide) can be well protected when the structural layer is stretched and the “Barrel Effect” of multi-materials film (different material films possess different stretchability) on one piece of substrate can also be solved. Besides, the localizedly modified PDMS as a substrate can form different 3D buckling structures on it by pre-stretching and releasing process compared with uniform PDMS, which shows a new way to control the 3D buckling structure.
The maintenance of terminally differentiated cells, especially hepatocytes, in vitro has proven challenging. Here we demonstrated the long-term in vitro maintenance of primary human hepatocytes (PHHs) by modulating cell signaling pathways with a combination of five chemicals (5C). 5C-cultured PHHs showed global gene expression profiles and hepatocyte-specific functions resembling those of freshly isolated counterparts. Furthermore, these cells efficiently recapitulated the entire course of hepatitis B virus (HBV) infection over 4 weeks with the production of infectious viral particles and formation of HBV covalently closed circular DNA. Our study demonstrates that, with a chemical approach, functional maintenance of PHHs supports long-term HBV infection in vitro, providing an efficient platform for investigating HBV cell biology and antiviral drug screening.