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•NiFe2O4-COF-chitosan-terephthalaldehyde nanocomposites film were fabricated.•The novel film NCCT could be separated rapidly in only 2 s without mass loss.•NCCT has high efficiency to ...remove antibiotic contaminants from water.•The adsorption mechanism of antibiotics on NCCT were explored.
Adsorption of tetracycline (TC) and cefotaxime (CTX) by novel NiFe2O4-COF-chitosan-terephthalaldehyde nanocomposites film (NCCT) was explored. To assess the feasibility of NCCT as a potential adsorbent for TC and CTX removal, a series of adsorption experiments were conducted. These results showed that the chemical crosslink of chitosan with terephthalaldehyde (TPA) restricted NCCT degradation of acid. In addition, NCCT as a film adsorbent could be separated completely in only 2 s without mass loss, much faster than any other magnetic materials. The abundant functional groups of chitosan, COF and TPA could significantly improve the adsorption capacity of NCCT on antibiotics. The pseudo-second-order kinetics model better illustrated the adsorption of TC and CTX onto NCCT, and the maximum adsorption capacity are 388.52 mg g−1 and 309.26 mg g−1, respectively. The nanocomposites film NCCT also exhibit excellent reproducibility after six adsorption cycles. In addition, various analysis results implied the adsorption mechanism of TC on NCCT was mainly through complexation, cation exchange, electrostatic attraction, hydrogen bonding and the π–π interaction. For CTX, the mechanism of adsorption included condensation reaction, electrostatic attraction, hydrogen bonding and π–π interaction. This kind of high-efficiency and novel nanocomposites film adsorbents can be ultrafastly separated from water, verifying NCCT has huge potential in water treatment for antibiotic contaminants removal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study investigates the relations between climate change and both runoff and sediment yield in watersheds and provides a scientific basis for water resources planning and design as well as ...watershed-scale soil and water conservation. The impact of climate change on runoff and sediment yield in a watershed does not occur in isolation, but is a synergistic process in which climate and vegetation jointly influence runoff and sediment yield. Previous studies have seldom addressed this synergistic effect. For this study, a regression model between climate factors (temperature and precipitation) and the Normalized Difference Vegetation Index (NDVI) was established using data from the Zhenjiangguan Watershed in China. By combining data on climate-driven changes in vegetation cover, the Soil and Water Assessment Tool (SWAT) model was built to simulate runoff and sediment yield in the watershed under two scenarios: changes in climate, and synergistic changes in climate and vegetation cover. The simulation results show that precipitation is the most sensitive factor affecting runoff and sediment yield; 10% change in annual precipitation can cause 10%–14% change in annual runoff and 17%–24% change in annual sediment yield. Temperature is also an important factor affecting runoff and sediment yield in the watershed. Each temperature increase of 0.7 °C can result in a decrease of 1.4%–2% in annual runoff and 2%–3.7% in annual sediment yield. This research reveals that accounting for synergetic change in vegetation has an impact on runoff and sediment yield results, and that the magnitude and nature of this influence vary among different combinations of temperature and precipitation changes. When temperature was kept constant, the effect of vegetation cover change caused by precipitation change on runoff and sediment yield was relatively small (only 0.9%–1.5% of the total change), and vegetation cover change inhibited the effects of precipitation change on runoff and sediment yield. When precipitation was kept constant, the effects of vegetation cover change caused by temperature change on runoff and sediment yield were relatively large (20%–30% of the total change), and vegetation cover change enhanced the effects of temperature change on runoff and sediment yield. This investigation considers the synergistic effects of climate and vegetation cover change, and thus further clarifies the extent to which climate change impacts water and ecological resources.
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•The laws of vegetation change due to climate change were investigated.•The distributed hydrological model and the vegetation change model were coupled.•The synergetic change and its impact on runoff and soil erosion were considered.•Vegetation synergetic change would influence runoff and erosion to a certain degree.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Clearly defining the responsibility for carbon emissions can help urban agglomerations achieve their carbon peak and facilitate the construction of a low-carbon society. With the regional ...professional division of labor and intricate economic and trade links, the phenomenon of carbon transfer between urban agglomerations has become increasingly obvious, making it difficult to scientifically divide carbon emission responsibility based solely on producer or consumer responsibility. Based on the constructed multi-regional input-output model of cities in China, we calculated the scale and direction of carbon emissions and net carbon transfer on the production and consumption sides of each urban agglomeration. Considering the asymmetry of producer and consumer responsibility and the proportion of value-added trade of urban agglomeration outflow as the responsibility sharing factor, we propose a scheme for the power and responsibility distribution of net carbon transfer of urban agglomeration. The results show that
In the context of uneven development studies of China, urban built-up area changes are the index of the impact of power, as the local government is the only party that is able to acquire agricultural ...land and convert it to construction urban land. Existing studies generally use statistical data to describe the built-up area changes and struggle to meet the requirement of an updated and inexpensive monitoring of uneven development, especially for western cities with tight budgets. Open access NPP-VIIRS (Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite), NDVI (Normalized Difference Vegetation Index), and nighttime LST (Land Surface Temperature) data ranging from 2015 to 2019 were analyzed with a stratified SVM (Support Vector Machine) method in this study to track urban built-up area changes in Chengdu, one of the biggest cities in Western China. The SDE (Standard Deviation Ellipse) and Moran’s I were then applied to evaluate the spatial variations of the built-up area changes. It was revealed that the spatial evolution of built-up area change in Chengdu over the period 2015–2019 demonstrated a “northwest-southeast” spatial expansion pattern, and the change distance in the center of gravity in 2018 and 2019 was greater than that from 2015 to 2017, which reflected the faster uneven development in 2018 and 2019 in Chengdu. The results were verified with finer resolution Landsat-8 OLI images; the high OA (all larger than 92%) and KAPPA (all larger than 0.6) values showed the accuracy of the method. The methodology proposed in this study offers a practical way for cities with tight budgets to monitor uneven development, and this study suggests a further adaption using higher-resolution remote sensing images and field experiments.
Urban spatial interaction integrates cities into closely related urban network systems in continuous urban regions. However, it also brings differentiation and has mutual negative impacts between ...each location. Unbalanced development is one such impacts and needs closely monitoring. The housing vacancy rate (HVR) in a continuous urban region is an important index in the unbalanced development of a continuous urban region since it indicates the uneven distribution of population and investment across cities. This study uses NPP-VIIRS NTL data and Landsat 8 OLT images to estimate HVRs at the district level. Additionally, this study tracks the spatial–temporal dynamics of HVR distributions in the Pearl River Delta (PRD) region. The comparison between the sampled HVRs and estimated HVRs verifies the effectiveness of the estimated HVRs in identifying dynamic changes in HVRs. This study has found that although overall decreasing HVRs are observed in the PRD, speculations and irrational real estate investment exist in cities on the west bank of the Pearl River Estuary and in some isolated districts in other cities. Furthermore, increasing proportions of vacant pixels in most cities indicate rising real estate development, requiring further supervision. This study suggests that more precise data and advanced techniques could help to improve the accuracy of the estimation techniques.
K and Na have been widely used in photocatalytic H2O2 production. However, Rb and Cs have rarely been studied for their photocatalytic potentials. In addition, the mechanism regulating H2O2 ...production from different alkali metal (M)-modified polymeric carbon nitride (PCN) is still unknown. Therefore, M-doped PCN was fabricated using thermal copolymerization in the presence of Li, Na, K, Rb, or Cs. The activity of CN-M was enhanced by the increase in the metallic character of alkali metals. However, CN-Cs’s photocatalytic H2O2 activity is not optimal even though it has the strongest metallic character. A stronger metallic character is anticipated to yield stronger Lewis acidic sites. Although ethanol can be adsorbed and activated at strong Lewis acidic sites, H2O2 can also be activated at these sites, which speeds up H2O2 degradation. CN-Rb—with its acceptable metallic character, excellent oxygen adsorption capacity, and reduced H2O2 degradation—has the best photocatalytic H2O2 yield.
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Enterococci are important pathogens of nosocomial infections and are increasingly difficult to treat due to their intrinsic and acquired resistance to a range of antibiotics. Therefore, ...there is an urgent need to develop novel antibacterial agents, while drug repurposing is a promising approach to address this issue. Our study aimed to determine the antimicrobial efficacy of halicin against enterococci and found that the minimum inhibitory concentrations (MIC) of halicin against different strains of Enterococcus faecalis and Enterococcus faecium ranged from 4 to 8 μg/ml. In addition, the synergistic antibacterial effect between halicin and doxycycline (DOX) against Enterococcus was observed through the checkerboard method, and it was observed that halicin and DOX could significantly synergistically inhibit biofilm formation and eradicate preformed biofilms at sub-MICs. Moreover, the electron microscope results revealed that halicin could also disrupt the bacterial cell membrane at high concentrations. Furthermore, it is also confirmed that the combination of halicin and DOX has no significant cytotoxic effect on erythrocytes and other human-derived cells. In addition, the mouse subcutaneous model and H&E staining showed that the combination of halicin and DOX could effectively reduce the bacterial load and inflammatory infiltration without obvious side effects. In nutshell, these results demonstrate the potential of halicin in combination with DOX as a novel therapy against infections by Enterococcus.
This study demonstrates the potential of halicin in combination with DOX as a novel therapy against infections by Enterococcus.
This paper proposes a proximity imaging sensor based on a tomographic approach with a low-cost conductive sheet. Particularly, by defining capacitance density, physical proximity information is ...transformed into electric potential. A novel theoretical model is developed to solve the capacitance density problem using the tomographic approach. Additionally, a prototype is built and tested based on the model, and the system solves an inverse problem for imaging the capacitance density change that indicates the object's proximity change. In the evaluation test, the prototype reaches an error rate of 10.0-15.8% in horizontal localization at different heights. Finally, a hand-tracking demonstration is carried out, where a position difference of 33.8-46.7 mm between the proposed sensor and depth camera is achieved at 30 fps.
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By integrating sensing capability into wireless communication, wireless sensing technology has become a promising contactless and non-line-of-sight sensing paradigm to explore the dynamic ...characteristics of channel state information (CSI) for recognizing human behaviors. In this paper, we develop an effective device-free human gesture recognition (HGR) system based on WiFi wireless sensing technology in which the complementary CSI amplitude and phase of communication link are jointly exploited. To improve the quality of collected CSI, a linear transform-based data processing method is first used to eliminate the phase offset and noise and to reduce the impact of multi-path effects. Then, six different time and frequency domain features are chosen for both amplitude and phase, including the mean, variance, root mean square, interquartile range, energy entropy and power spectral entropy, and a feature selection algorithm to remove irrelevant and redundant features is proposed based on filtering and principal component analysis methods, resulting in the construction of a feature subspace to distinguish different gestures. On this basis, a support vector machine-based stacking algorithm is proposed for gesture classification based on the selected and complementary amplitude and phase features. Lastly, we conduct experiments under a practical scenario with one transmitter and receiver. The results demonstrate that the average accuracy of the proposed HGR system is 98.3% and that the F1-score is over 97%.
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After an osteosarcoma excision, recurrence and bone defects are significant challenges for clinicians. In this study, the curcumin (Cur) loaded chitosan (CS) nanoparticles (CCNP) encapsulated silk ...fibroin (SF)/hyaluronic acid esterified by methacrylate (HAMA) (CCNPs-SF/HAMA) hydrogel for the osteosarcoma therapy and bone regeneration was developed by photocuring and ethanol treatment. The micro or nanofibers networks were observed in the CCNPs-SF/HAMA hydrogel. The FTIR results demonstrated that alcohol vapor treatment caused an increase in β-sheets of SF, resulting in the high compression stress and Young’s modulus of CCNPs-SF/HAMA hydrogel. According to the water uptake analysis, SF caused a slight decrease in water uptake of CCNPs-SF/HAMA hydrogel while CCNPs could enhance the water uptake of it. The swelling kinetic results showed that both the CCNPs and the SF increased the swelling ratio of CCNPs-SF/HAMA hydrogel. The accumulative release profile of CCNPs-SF/HAMA hydrogel showed that the release of Cur from CCNPs-SF/HAMA hydrogel was accelerated when pH value was decreased from 7.4 to 5.5. Besides, compared with CCNPs, the CCNPs-SF/HAMA hydrogel had a more sustainable drug release, which was beneficial for the long-term treatment of osteosarcoma. In vitro assay results indicated that CCNPs-SF/HAMA hydrogel with equivalent Cur concentration of 150 μg/mL possessed both the effect of anti-cancer and promoting the proliferation of osteoblasts. These results suggest that CCNPs-SF/HAMA hydrogel with superior physical properties and the bifunctional osteosarcoma therapy and bone repair may be an excellent candidate for local cancer therapy and bone regeneration.
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