As the abuse of antibiotics continues to increase, the emergence of antibiotic resistance and unknown drug-resistant bacterial infections pose a great threat on people worldwide. In this work, we ...aimed to develop a series of injectable antimicrobial conductive hydrogels based on glycidyl methacrylate functionalized quaternized chitosan (QCSG), gelatin methacrylate (GM), and graphene oxide (GO) for drug-resistant bacterial disinfection and infectious wound healing. The rheology, morphology, mechanical properties, and electrical and photothermal properties of the hydrogels were characterized. Furthermore, the good in vitro and in vivo intrinsic antibacterial, photothermal antibacterial, and antibiotics released antibacterial properties of this multiantibacterial hydrogel were verified. The good biocompatibility of these hydrogels was also investigated by cytocompatibility, hemocompatibility, and histocompatibility tests. In the drug-resistant Methicillin-resistant Staphylococcus aureus (MRSA) infected mouse full-thickness defect model, the wound closure rate, the length of dermal tissue gap, number of blood vessels and hair follicles in hematoxylin-eosin (HE) staining, the amount of collagen in Masson staining, and the related cytokines for the expression of inflammation (interleukin-6, IL-6) and regeneration of blood vessels (vascular endothelial growth factor, VEGF) in immunofluorescence were all further studied. All the results demonstrated the better wound healing effect of these multiantibacterial injectable conductive hydrogel in infectious skin tissue defect repair, indicating their great potential for infected wound healing.
Nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material is coated with nano-sized anatase TiO2 synthesized via hydrolyzation method to improve its electrochemical performance at high cutoff voltage of ...4.5 V. Scanning electron microscopy (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) results show that the anatase TiO2 is successfully coated on the surface of LiNi0.6Co0.2Mn0.2O2 with nanoscale and the coating layer thickness is about 25–35 nm. X-ray diffraction (XRD) test results indicate that appropriate amount of TiO2 coating is beneficial to form a good layered structure with less cation disorder. Charge–discharge test results demonstrate that the TiO2-coated LiNi0.6Co0.2Mn0.2O2 presents excellent cycling capability, rate capability and thermal stability at cutoff voltage of 4.5 V. The 1.0 wt.% TiO2-coated LiNi0.6Co0.2Mn0.2O2 exhibits a capacity retention of 88.7% after 50 cycles at 1 C and a discharge capacity of 135.8 mAh g−1 after 10 cycles at 5 C, comparing to those of the pristine LiNi0.6Co0.2Mn0.2O2 of only 78.1% and 85.4 mAh g−1. Electrochemical impedance spectroscopy (EIS) and differential scanning calorimeter (DSC) tests results provide evidence that the improved electrochemical properties are mainly attributed to the suppression of the interface reaction between the cathode and electrolyte and the improvement of structural stability of the material by coating.
•Anatase nano-TiO2 is successfully coated on the surface of LiNi0.6Co0.2Mn0.2O2.•Appropriate amount of TiO2 is beneficial to reduce cation disorder.•The 1.0 wt.% TiO2-coated LiNi0.6Co0.2Mn0.2O2 exhibits excellent electrochemistry properties.•The TiO2-coated LiNi0.6Co0.2Mn0.2O2 presents excellent thermal stability.
Characteristics of raindrop size distribution (DSD) during the Meiyu season are studied using ground-based disdrometer measurements carried out in eastern China (Nanjing) from 2009 to 2011. The ...observational spectra are divided into convective and stratiform types. The results show that the histograms of the logarithm of the generalized intercept parameter (log10NW) and mass-weighted mean diameter of raindrops (Dm) are negatively and positively skewed, respectively, for both convective and stratiform rain. The absolute value of the skewness coefficient is higher for convective rain than for stratiform rain, in particular for the log10NW distribution. The mean log10NW and Dm values are 3.80 and 1.71 mm for convective rain and 3.45 and 1.30 mm for stratiform rain, respectively. The shape (μ)—slope (Λ) relationship of the gamma distribution and the radar reflectivity (Z)—rain rate (R) relationship are also derived for convective rain. The Z-R relationship is found to be Z = 368R1.21. The interpretation of the statistical parameters obtained in this study and possible mechanisms that yield difference and similarity in comparison with those in previous studies are discussed.
Disdrometer data measured by ground-based optical disdrometers during a midlatitude continental squall line event on 18 August 2012 in Shandong Province, eastern China, are analyzed to study ...characteristics of raindrop size distribution (DSD). Four disdrometers simultaneously performed continuous measurements during the passage of the convective line. The convective line was partitioned into three regions: the convective center, leading edge, and trailing edge. Results show distinct differences in DSDs and integral rainfall parameters between the convective-center and the edge regions. The convective center has higher drop concentrations, larger mean diameters, and wider size distributions when compared with the edge regions. The leading and trailing edges have similar drop concentrations, but the latter has larger mean diameters and wider size distributions. The shape of DSD for the convective center is convex down, whereas it is convex upward in tropical continental squall lines, as reported in the literature. There is also spatial variability of the DSD and its integral rainfall parameters in the along-convective-line direction.
Cerium fluoride (CeF3) coated lithium-rich layered Li1.2Mn0.54Ni0.13Co0.13O2 particles are synthesized using a facile chemical deposition route. The structural and electrochemical properties of ...pristine and CeF3-coated electrodes are investigated by X-ray diffraction (XRD), thermogravimetric-differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), galvanostatic charge/discharge tests, electrochemical impedance spectra (EIS) and cyclic voltammetry (CV). The results indicate that the cathode particles are uniformly covered with a CeF3 layer (∼10 nm thick) after 2 wt.% CeF3 surface coating. The coated electrode shows an enhanced initial coulombic efficiency of 80.8% compared to 75.2% for the pristine electrode. Moreover, the coated electrode demonstrates better cyclic performance, which exhibits capacity retention of 91.7% after 50 cycles compared with only 82.1% for the pristine one. Furthermore, the CeF3-coated electrode delivers a superior high-rate capacity of 103.1 mAh g−1 at 5C, higher than 82.2 mAh g−1 for the pristine one. The remarkably improved cycling stability and high-rate capacity of the surface-modified electrode is ascribed to the presence of a stable and thin CeF3 coating layer which effectively reduces the damage of electrode structure and suppresses the increase of impedance during cycling by preventing direct contact of electrode with electrolyte.
•Cerium fluoride is used as a novel coating material for Li-rich layered cathode.•Coated cathode displays enhanced high-rate capability and cycling stability.•Coating layer suppresses the increase of electrochemical impedance of electrode.
Cotton production is adversely effected by drought stress. It is exposed to drought stress at various critical growth stages grown under a water scarcity environment. Roots are the sensors of plants; ...they detect osmotic stress under drought stress and play an important role in plant drought tolerance mechanisms. The seedling stage is very sensitive to drought stress, and it needed to explore the methods and plant characteristics that contribute to drought tolerance in cotton. Initially, seedlings of 18 genotypes from three Gossypium species: G. hirsutum, G. barbadense, and G. arboreum, were evaluated for various seedling traits under control (NS) and drought stress (DS). Afterward, six genotypes, including two of each species, one tolerant and one susceptible, were identified based on the cumulative drought sensitivity response index (CDSRI). Finally, growth rates (GR) were examined for shoot and root growth parameters under control and DS in experimental hydroponic conditions. A significant variation of drought stress responses was observed across tested genotypes and species. CDSRI allowed here to identify the drought-sensitive and drought-resistant cultivar of each investigated species. Association among root and shoots growth traits disclosed influential effects of enduring the growth under DS. The traits including root length, volume, and root number were the best indicators with significantly higher differential responses in the tolerant genotypes. These root growth traits, coupled with the accumulation of photosynthates and proline, were also the key indicators of the resistance to drought stress. Tolerant genotypes have advanced growth rates and the capacity to cop with drought stress by encouraging characteristics, including root differential growth traits coupled with physiological traits such as chlorophyll and proline contents. Tolerant and elite genotypes of G. hirsutum were more tolerant of drought stress than obsolete genotypes of G. barbadense and G. arboreum. Identified genotypes have a strong genetic basis of drought tolerance, which can be used in cotton breeding programs.
Allowing amputees to volitionally control robotic prostheses can improve the adaptability to terrain changes. In this paper, we propose a myoelectric controller for a robotic transtibial prosthesis ...to realize adaptive slope walking. It works together with the intrinsic controller, enabling amputee users to pay relatively less attention on myoelectric control during walking. Amputee users convey the information of ground slope to prostheses by consciously performing dorsiflexion and plantar flexion of the "phantom ankle" with different intensities at the beginning of the swing phase. Two channels of surface electromyographic signals are measured from the residual shank, and they are mapped to the inclination angle of the slope. Control parameters of the intrinsic controller are then calculated according to the estimated inclination angle. In this preliminary study, two transtibial amputee subjects were recruited. They were asked to convey six targeted inclination angles (±5°, ±10°, and ±15°) to the prosthesis with the trained myoelectric controller during level-ground walking, and satisfactory control performance was achieved. This experiment was designed to simulate the scenario of transiting from level-ground walking to slope walking. Experimental results of controlling the robotic prosthesis to walk on level ground and slopes further verified that it is promising for amputees to adaptively walk on the ground with varied inclination angles in daily life.
The number of exoskeletons providing load-lifting assistance has significantly increased over the last decade. In this field, to take full advantage of active exoskeletons and provide appropriate ...assistance to users, it is essential to develop control systems that are able to reliably recognize and classify the users' movement when performing various lifting tasks. To this end, the movement-decoding algorithm should work robustly with different users and recognize different lifting techniques. Currently, there are no studies presenting methods to classify different lifting techniques in real time for applications with lumbar exoskeletons. We designed a real-time two-step algorithm for a portable hip exoskeleton that can detect the onset of the lifting movement and classify the technique used to accomplish the lift, using only the exoskeleton-embedded sensors. To evaluate the performance of the proposed algorithm, 15 healthy male subjects participated in two experimental sessions in which they were asked to perform lifting tasks using four different techniques (namely, squat lifting, stoop lifting, left-asymmetric lifting, and right-asymmetric lifting) while wearing an active hip exoskeleton. Five classes (the four lifting techniques plus the class "no lift") were defined for the classification model, which is based on a set of rules (first step) and a pattern recognition algorithm (second step). Leave-one-subject-out cross-validation showed a recognition accuracy of 99.34 ± 0.85%, and the onset of the lift movement was detected within the first 121 to 166 ms of movement.
As part of the third Tibetan Plateau Atmospheric Scientific Experiment field campaign, raindrop size distribution (DSD) measurements were taken with a laser optical disdrometer in Naqu, China, at ...4,508 m above sea level (asl) during the summer months of 2013, 2014, and 2015. The characteristics of DSDs for five different rain rates, for two rain types (convective and stratiform), and for daytime and nighttime rains were studied. The shapes of the averaged DSDs were similar for different rain rates, and the width increased with rainfall intensity. Little difference was found in stratiform DSDs between day and night, whereas convective DSDs exhibited a significant day‐night difference. Daytime convective DSDs had larger mass‐weighted mean diameters (Dm) and smaller generalized intercepts (NW) than the nighttime DSDs. The constrained relations between the intercept N0 and shape μ, slope Λ and μ, and NW and Dm of gamma DSDs were derived. We also derived empirical relations between Dm and the radar reflectivity factor in the Ku and Ka bands.
Key Points
The shapes of the averaged DSDs are similar for different rain rates, and the spectral width increases with rainfall intensity
Convective DSDs for daytime have larger Dm and smaller NW as compared to nighttime. Stratiform DSDs are similar between day and night
Constrained relations between gamma distribution parameters and mass‐weighted mean diameter and GPM DPR reflectivity factors are derived
Mixed‐phase stratiform clouds contain numerous liquid, mixed‐phase, and ice clusters, quantifying the cluster scales is potentially helpful to improve the parameterizations of microphysics and ...radiation models. However, the scales of hydrometeor clusters at different levels of stratiform clouds are not well understood. In this study, using airborne measurements and a large eddy simulation, we show that turbulence plays an important role in controlling the clusters with length of a few hundred meters, while the scales of larger clusters have stronger vertical variations from cloud base to top. The liquid clusters are the largest near the cloud top, while the lengths of ice clusters decrease from cloud base to top. The lengths of mixed‐phase clusters depend on the glaciation process, a faster glaciation results in smaller mixed‐phase clusters. The results improve our understanding on how the liquid and ice are mixed at different levels in stratiform clouds.
Plain Language Summary
Mixed‐phase clouds are vital to the global radiative balance and water cycle. The coexistence of liquid and ice, and the way they mix have significant impacts on the cloud microphysical properties. Observations suggest hydrometeors organize in clusters in mixed‐phase stratiform clouds, while such inhomogeneity is still poorly represented in models. In this study, using airborne measurements and model simulation, we analyzed the scales of liquid, mixed‐phase, and ice clusters at different levels in a stratiform cloud observed in Northeast China. The results suggest turbulence controls the scale of clusters with length of a few hundred meters, while larger clusters have stronger vertical variations. The results improve our understanding on the cluster scales of hydrometeors at different levels in stratiform clouds, and are potentially helpful to improve the parameterizations of microphysics and radiation.
Key Points
Turbulence plays an important role in controlling the scale of hydrometeor clusters
The scales of liquid, mixed‐phase, and ice clusters have different height dependencies from cloud top to base
A faster glaciation process results in smaller mixed‐phase clusters
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