Flexible pressure sensors that can maintain their pressure sensing ability with arbitrary deformation are of important significance in the fields of electronic skin, human-machine interfaces and ...medical diagnosis and treatment. To date, flexible pressure sensors have been studied extensively, and diverse transduction principles as well as different structural designs can be introduced to produce flexible pressure sensors that are capable of conformably covering an arbitrary surface. Moreover, high-performance flexible pressure sensors have been designed for different application needs. For example, high-resolution flexible pressure sensor arrays have been achieved based on piezoelectric nanowires (NWs); meanwhile crack-based pressure sensors with an extraordinarily simple structure have high sensitivity to tiny pressure, such as sound and physiological signals. For broader applications, endowing flexible pressure sensors with the sensing abilities of temperature, humidity and other stimuli are being developed to mimic the somatosensory system of human skin. In recent years, the development of novel flexible pressure sensors has been burgeoning with new sensors developed with self-powered, self-healing and biodegradable abilities. Here, we present comprehensive descriptions of the recent flexible pressure sensors, and then propose the potential prospects of flexible pressure sensors integrated with high sensitivity, high resolution, fast response, good stretchability and a wide detection range together, further enriching the multifunctions of flexible pressure sensors.
This review summarizes the progress in flexible pressure sensor arrays from their fundamental designs to device applications.
•A comprehensive overview of climate change impacts on fish growth was conducted.•Less than 1% of the recorded fish species are examined under this topic.•Temperate fishes and marine fishes are the ...most frequently studied objects.•Small-size and low-trophic level fishes are generally under-evaluated.•The overall negative effects are mainly attributed to temperature variables.
Global climate change is increasingly and profoundly threatening fishes, resulting in an uncertain future for both wild fish diversity and global fisheries. Understanding how fish growth responds to changing environments is essential for indicating and predicting the impacts of climate change on fish populations, communities, and even aquatic ecosystems, but the knowledge on this topic remains incomplete, and some findings are contradictory. This study aimed to review the status of current research by analysing data on the environment, species, and response patterns from 1187 documents published from 1976 to 2018, which helped to identify key questions that are currently neglected and potential reasons for these divergences. The results found that 75% of studies were conducted in the field (mostly in temperate and subtropical zones), while the remainder were controlled experiments. Fishes from freshwater ecosystems were relatively less studied than their marine counterparts. Less than 1% of the recorded fish species (309 vs. approximately 35,000) from 30 orders have been studied to examine their growth responses to climate change. All studied fishes were from Actinopterygii. The top three orders were Perciformes, Cypriniformes, and Salmoniformes by species number, while Salmoniformes was the most frequently studied order. The most common habitat type of the studied fish was pelagic, followed by demersal and reef-associated habitats. Small fishes were relatively undervalued in both marine and freshwater systems. The mean trophic levels of the studied species were 3.2 for freshwater fish and 3.4 for marine fish. Carnivores were the dominant trophic guild studied in both marine and freshwater systems. The overall effects of climate change (primarily temperature variables) on fish growth (reflected in physiology and health) were negative at both the global and local scales. Therefore, the results suggested that future studies covering more species (e.g., chondrichthyan fishes, low-level consumers, and small fishes) and areas (e.g., high-latitude areas) are required to obtain a better understanding of climate change impacts on fish growth.
Abstract
Soil arching exists in many earth structures, such as pile-supported embankments, tunnels, buried pipes, and retaining walls. These earth structures are sometimes subjected to surface ...footing loading. Limited studies showed that surface footing loading weakened active soil arching formed in backfill material; however, this effect has not been well considered in the current design. In this study, two-dimensional (2D) trapdoor tests with transparent soil were carried out to investigate the development of active soil arching under static surface footing loading. The particle image velocimetry (PIV) technique was adopted to monitor the deformations of soil particles due to multiple trapdoor movements and surface footing loadings. Soil arches with a triangular expanding pattern and a tower-shaped development pattern were observed in the cases with different fill heights. Under the surface footing load, soil arching first degraded locally (at its crown) and then gradually expanded to both sides of the arch with an increase of load magnitude until full degradation of soil arching globally. The model tests with active soil arching resulted in a larger surface settlement under a footing load than that without soil arching due to the volumetric expansion of the soil during the formation of soil arching. Two analytical methods were compared with the experimental results before local degradation and after global degradation of soil arching.
•Contra-diffusion in conjunction with P4VP grafted modification for PVDF/ZIF-8.•A well-intergrown and continuous ZIF-8 layer can be formed at Zn/mIm/SF=1:8:1.344.•The iodine adsorption capacity of ...PVDF/ZIF-8 is 73.33 mg/g in batch adsorption.•The iodine removal efficiency of PVDF/ZIF-8 is high as 73% in dynamic adsorption.
Metal-organic frameworks (MOFs) are capable in capture and storage of iodine ions with high efficiency, and polymer/MOF nanocomposite membrane has the potential to be used for efficient removal of iodine from radioactive wastewater. In this work, we have reported a PVDF/ZIF-8 nanocomposite adsorption membrane prepared by contra-diffusion method. The combination of surface graft of poly(4-vinylpyridien) brushes and optimal addition of sodium formate into ligand contributes to the formation of a well-intergrown and continuous ZIF-8 layer on the metal ions side surface of PVDF-g-P4VP membrane. In the batch adsorption, the PVDF/ZIF-8 nanocomposite membrane exhibits high affinity for iodine following a pseudo-second-order kinetics and fitting the Freundlich isotherm model with a maximum adsorption capacity of 73.33 mg/g. In the dynamic adsorption, the PVDF/ZIF-8 nanocomposite membrane exhibits a high flux of 66.19 L/(m2⋅h⋅MPa) and an iodine removal efficiency of 73% until 180 min. Initial iodine concentration has a little influence on the iodine removal efficiency, but solution pH shows a significant effect. The iodine removal efficiency can be maintained around 92% in a weakly alkaline medium of pH = 8. The PVDF/ZIF-8 nanocomposite membrane possesses an excellent reusability with an iodine removal efficiency of 73.4% after five cycles.
Dam removal has been increasingly reported globally and is becoming an important approach for river management, restoration and environmental conservation in damming rivers. However, current limited ...knowledge of global trends in dam removal and related research may be potentially biased in terms of the geographic distribution and organisms studied. Such bias could mislead dam removal planning and management in different areas and ecological conservation for different taxa. In this study, we quantitatively and qualitatively analyzed datasets of dam removal and publications of dam removal research using bibliometric methods. A total of 1449 dam removal documents were published from 1953 to 2016. Trends, current hotspots and future directions of dam removal research were identified. The results from this study reveal that dam removal largely occurred in the North America and Europe, and most of the removed dams were small and old dams. With respect to the topic analysis, more dam removal studies should focus on the responses of a wide range of organisms, not only fish, as well as the interspecies relationships, food webs and ecosystem structures and functions. Based on our findings, we also provide some suggestions for future dam removal planning and analysis.
Recently, stretchable electronics combined with wireless technology have been crucial for realizing efficient human-machine interaction. Here, we demonstrate highly stretchable transparent wireless ...electronics composed of Ag nanofibers coils and functional electronic components for power transfer and information communication. Inspired by natural systems, various patterned Ag nanofibers electrodes with a net structure are fabricated via using lithography and wet etching. The device design is optimized by analyzing the quality factor and radio frequency properties of the coil, considering the effects of strain. Particularly, the wireless transmission efficiency of a five-turn coil drops by approximately only 50% at 10 MHz with the strain of 100%. Moreover, various complex functional wireless electronics are developed using near-field communication and frequency modulation technology for applications in content recognition and long-distance transmission (>1 m), respectively. In summary, the proposed device has considerable potential for applications in artificial electronic skins, human healthcare monitoring and soft robotics.
The enzyme catalysis conversion of lignocellulosic biomass into valuable chemicals and fuels showed a bright outlook for replacing fossil resources. However, the high cost and easy deactivation of ...free enzymes restrict the conversion process. Immobilization of enzymes in metal-organic frameworks (MOFs) is one of the most promising strategies due to MOF materials' tunable building units, multiple pore structures, and excellent biocompatibility. Also, MOFs are ideal support materials and could enhance the stability and reusability of enzymes. In this paper, recent progress on the conversion of cellulose, hemicellulose, and lignin by MOF-immobilized enzymes is extensively reviewed. This paper focuses on the immobilized enzyme performances and enzymatic mechanism. Finally, the challenges of the conversion of lignocellulosic biomass by MOF-immobilized enzyme are discussed.
The ocean wave
energy is one of the most promising renewable and clean energy sources for human life,
which is the so-called “Blue energy.” In this work, a nanowire based triboelectric
nanogenerator ...was designed for harvesting wave energy. The nanowires on the surface of FEP largely raise the
contacting area with water and also make the polymer film hydrophobic. The output can reach 10
μ
A
and 200 V. When combined with a capacitor, an infrared emitter,
and a receiver, a self-powered wireless infrared system is fabricated, which can be used
in the fields of communication and detecting.
Purpose
The purpose of this study is to develop a radiomics model for predicting the Ki-67 proliferation index in patients with invasive ductal breast cancer through magnetic resonance imaging (MRI) ...preoperatively.
Materials and methods
A total of 128 patients who were clinicopathologically diagnosed with invasive ductal breast cancer were recruited. This cohort included 32 negative Ki67 expression (Ki67 proliferation index < 14%) and 96 cases with positive Ki67 expression (Ki67 proliferation index ≥ 14%). All patients had undergone diffusion-weighted imaging (DWI) MRI before surgery on a 3.0T MRI scanner. Radiomics features were extracted from apparent diffusion coefficient (ADC) maps which were obtained by DWI-MRI from patients with invasive ductal breast cancer. 80% of the patients were divided into training set to build radiomics model, and the rest into test set to evaluate its performance. The least absolute shrinkage and selection operator (LASSO) was used to select radiomics features, and then, the logistic regression (LR) model was established using fivefold cross-validation to predict the Ki-67 index. The performance was evaluated by receiver-operating characteristic (ROC) analysis, accuracy, sensitivity and specificity.
Results
Quantitative imaging features (
n
= 1029) were extracted from ADC maps, and 11 features were selected to construct the LR model. Good identification ability was exhibited by the ADC-based radiomics model, with areas under the ROC (AUC) values of 0.75 ± 0.08, accuracy of 0.71 in training set and 0.72, 0.70 in test set.
Conclusions
The ADC-based radiomics model is a feasible predictor for the Ki-67 index in patients with invasive ductal breast cancer. Therefore, we proposed that three-dimensional imaging features from ADC maps could be used as candidate biomarker for preoperative prediction the Ki-67 index noninvasively.
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