•Titania-decorated graphene-based sensor was fabricated by layer-by-layer (LbL) self-assembly route.•Sensing properties of titania/graphene composite toward SO2 gas were investigated.•The sensor ...exhibited ppb-level detection, good reversibility, selectivity and repeatability for SO2 gas sensing.
This paper demonstrates layer-by-layer (LbL) self-assembled titania (TiO2)/graphene film device towards ultralow sulfur dioxide (SO2) gas sensing at room temperature. The as-prepared film was realized through the layer-by-layer alternative deposition of TiO2 nanospheres and graphene oxide (GO) to form a nanostructure, and followed by thermally reducing GO into reduced graphene oxide (rGO). The nanostructural, morphological and compositional properties of TiO2/rGO sample was examined by SEM, TEM, XRD, EDS and Raman spectroscopy. The gas-sensing properties of TiO2/rGO hybrid were investigated at room temperature against low concentration SO2 gas. The sensor in our work exhibited ppb-level detection, rapid response and recovery, good reversibility, selectivity and repeatability for SO2 gas sensing. The possible sensing mechanism for the presented sensor was attributed to the synergistic effect of TiO2 and rGO, as well as special interaction at TiO2/rGO interfaces. This work shows that the fabricated TiO2/rGO film sensor possesses potential applications for SO2 detection with advantages of cost-effective, low power consumption and distinguished sensing abilities.
Heavy metal pollution has become a global health challenge. Exposure to heavy metals represents a major health risk. Manganese (Mn) is an essential trace element but also an environmental pollutant. ...Mn exposure can induce neurotoxicity and lead to neurodegenerative disease. Inflammation and Tau hyperphosphorylation are prominent hallmarks of neurodegenerative diseases induced by Mn exposure. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway can induce powerful innate immune defense programmes and has emerged as a key mediator of inflammation. In recent years, Mn
has been found to be the second activator of the cGAS-STING pathway in addition to double-stranded DNA (dsDNA). NLRP3 activation is upstream of Tau pathology, and NLRP3 activation induces Tau hyperphosphorylation and aggregation. Mn exposure-induced neurotoxicity may be associated with excessive activation of the cGAS-STING signaling pathway, leading to inflammation. The cGAS-STING/NLRP3 axis may be a promising option for revealing the mechanisms of neurotoxicity of Mn exposure in the future.
Polymer nanocomposites have been extensively investigated over the past two decades, resulting in a wide range of applications because of their excellent performance. Halloysite, a type of naturally ...occurring aluminosilicate, has attracted increasing interest in polymer nanocomposite applications, especially for the enhancement of mechanical properties owing to its tubular structure. Herein, we report a facile approach to achieve a high level of dispersion of halloysite nanotubes (HNTs) in epoxy by treating HNTs with a low concentration of sodium hydroxide (NaOH). The NaOH treatment resulted in the formation of hydroxyl groups on the surface of HNTs, leading to a much higher level of dispersion of HNTs in water, organic polar solvents, and epoxy matrix. The higher density of external silanol groups (Si–OH) of hydroxylated HNTs (h-HNTs) was confirmed by X-ray photoelectron spectroscopy (XPS) characterization. Such a higher level of dispersion and stronger interface led to simultaneous enhancement in both the stiffness and the toughness of epoxy/h-HNT nanocomposites. Systematic characterizations were performed to investigate the related stiffening and toughening mechanism. The implication of the present findings is discussed.
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•The halloysite nanotubes were treated with a low concentration of sodium hydroxide.•The treated halloysite showed good dispersion in polar solvents, and epoxy matrix.•The epoxy/treated halloysite nanocomposite showed enhancing mechanical properties.
For the better utilization of solar light and complete oxidation of environmental organic pollutants, it is desired to develop small band gap semiconductors with a deep valence band as efficient ...visible light photocatalysts. In this work, we prepared the fluorinated Bi2O3 catalysts using a precipitation method, followed by a solvothermal process in the presence of NH4F. The fluorinated Bi2O3 catalysts, especially with the atomic ratio of F to Bi (R F) at 0.2, exhibit much higher photocatalytic activities than the pure Bi2O3 for the degradation of methyl orange (MO) under the visible light irradiation. The effects of the fluorination on the phase structure, special surface areas, morphologies, optical properties, surface-adsorbed species, and electronic band structure of the Bi2O3 were investigated in detail. It was revealed that both the surface-adsorbed and lattice-substituted fluorine, induced by the fluorination to Bi2O3, play critical roles in the enhanced photocatalytic performance of the fluorinated Bi2O3. The two types of fluorine species effectively inhibit the recombination of the photoexcited electron–hole pairs by withdrawing the photoexcited electrons and increase the oxidation power of the photoexcited hole by lowering the valence band edge, respectively.
This study was conducted to investigate the relationship between serum endothelial dysfunction-related biomarker levels and organ dysfunction severity in septic patients and the predictive value of ...these levels during sepsis. In total, 105 patients admitted to the Department of Critical Care Medicine were enrolled between September 2020 and November 2021. Serum syndecan-1 and soluble thrombomodulin(sTM) levels were measured by enzyme-linked immunosorbent assay, and clinical and laboratory data were recorded. Enroll patients were divided into the infection (n = 28), septic nonshock (n = 31), and septic shock (n = 46) groups . Serum syndecan-1 (102.84 ± 16.53 vs. 55.38 ± 12.34 ng/ml), and sTM(6.60 ± 1.44 ng/ml vs. 5.23 ± 1.23 ng/ml, P < 0.01) levels were increased in the septic group compared with those in the infection group. Serum syndecan-1 levels were closely positively correlated with serum sTM (r
= 0.712, r
= 0.507, P < 0.001). Additionally, serum syndecan-1(r
= 0.687, r
= 0.472, P < 0.001) and sTM levels (r
= 0.6, r
= 0.36, P < 0.01) levels were significantly positively correlated with the sequential organ failure assessment scores respectively. Syndecan-1 (AUC 0.95 ± 0.02, P < 0.0001) was more valuable for prediction sepsis than was sTM (AUC 0.87 ± 0.04, P < 0.0001). Compared with sTM (AUC 0.88 ± 0.03, P < 0.001), syndecan-1 (AUC 0.95 ± 0.02, P < 0.001) and SOFA score (AUC 0.95 ± 0.02, P < 0.001) were better predictors of septic shock. Serum syndecan-1 and sTM levels were associated with organ dysfunction severity in septic patients, and both were good predictors for early identification of sepsis, particularly in patients undergoing septic shock.
Nanoscale coordination polymers (NCPs) are promising nanomedicine platforms featured with biodegradability and versatile functionalities. However, multi-step post-synthesis surface modification is ...usually required to functionalize as-made NCPs before their biomedical applications. Moreover, efforts are still required to design therapeutic NCPs responsive to the unique tumor microenvironment to achieve more specific and effective therapy. Herein, we uncover a simple yet general strategy to synthesize a series of polyethylene glycol (PEG) modified NCPs via a one-step method by adding poly-histidine-PEG co-polymer into the mixture of metal ions and organic ligands during NCPs formation. With NCPs consisting Ca2+/dicarboxylic cisplatin (IV) prodrug as the example, we show that such Ca/Pt(IV)@pHis-PEG NCPs are highly sensitive to pH changes. With slightly negative charges and compact structure under pH 7.4 during blood circulation, those NCPs exhibit efficient passive accumulation in the tumor, in which the reduced pH (c.a. 6.5) would trigger charge conversion and size expansion to enhance their tumor retention and cell internationalization. After cellular uptake, NCPs within cell endo-/lysosomes with further reduced pH would then lead to decomposition of those NCPs and thus drug release. Chemotherapy with Ca/Pt(IV)@pHis-PEG NCPs in our animal tumor model demonstrates great efficacy under low drug doses, and is found to be particularly effective towards solid tumors with reduced pH.
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This paper demonstrated a hybrid composite of tin oxide-reduced graphene oxide (rGO) for ppm-level detection of ethanol vapour. A facile and low-cost method of hydrothermal synthesis was used to ...construct the SnO
2
-rGO hybrid film on a PCB substrate with coil-like interdigital microelectrodes. The presence of small-sized SnO
2
nanocrystals on rGO sheets was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), an X-ray diffractometer (XRD) and Brunauer-Emmett-Teller (BET) measurements. The sensing properties of the SnO
2
-rGO hybrid film sensor, including the sensitivity, response-recovery times and repeatability, were investigated by exposing it to various concentrations of ethanol gas varying from 1 ppm to 100 ppm at room temperature. As a result, the presented sensor exhibited a low detection limit of 1 ppm at room temperature, as well as a fast response-recovery time and good repeatability, which outstripped that of pure rGO film sensors. Finally, the possible mechanism of ethanol gas-sensing for the above presented sensor was discussed in detail.
This paper demonstrated a hybrid composite of tin oxide-reduced graphene oxide (rGO) for ppm-level detection of ethanol vapour.
Noble metals such as gold and silver are conventionally used as the primary plasmonic building blocks of optical metamaterials. Making subwavelength-scale structural elements from these metals not ...only seriously limits the optical performance of a device due to high absorption, it also substantially complicates the manufacturing process of nearly all metamaterial devices in the optical wavelength range. As an alternative to noble metals, we propose to use heavily doped oxide semiconductors that offer both functional and fabrication advantages in the near-infrared wavelength range. In this letter, we replace a metal with aluminum-doped zinc oxide as a new plasmonic material and experimentally demonstrate negative refraction in an Al:ZnO/ZnO metamaterial in the near-infrared range.
Tourism is not neutral with respect to local quality of life. With the transformation of traditional city roles and the boom of urban tourism in China, the interaction between tourism and local ...livability is increasingly important for sustainable development plans of urban areas. Our paper aims to address the complex interdependence of the emerging tourist industry and local livability in Chinese cities. Based on a conceptual model and a subsequent empirical statistical analysis of 35 large and medium-sized Chinese cities for the years 2003–2012, our study finds that urban livability and its related factors benefit tourism development, and that, in turn, tourism has a reverse impact on livability in urban areas; their performance appears to vary in different sub-regions and for different factors of livability; the geographic interdependence between livability and tourism development is also remarkable. Potential threats from excessive tourism development on urban livability, in particular in the Chinese Eastern and Central large and medium-sized cities, can be inferred from our empirical analysis. These conclusions may lead to important lessons to policy makers, while various suggestions based on our findings are provided as well.
•Interactions between urban livability and tourism development are complex.•Livability in cities and its determinants benefit the tourism sector.•Tourism is not always compatible with livability in China.•High tourism growth in Eastern and Central China may be a threat to livability.
Mulching practices have long been used to modify the soil temperature and moisture conditions and thus potentially improve crop production in dryland agriculture, but few studies have focused on ...mulching effects on soil gaseous emissions. We monitored annual greenhouse gas (GHG) emissions under the regime of straw and plastic film mulching using a closed chamber method on a typical winter-wheat (Triticum aestivum L. cv Xiaoyan 22) and summer-maize (Zea mays L. cv Qinlong 11) rotation field over two-year period in the Loess Plateau, northwestern China. The following four field treatments were included: T1 (control, no mulching), T2 (4000kgha−1 wheat straw mulching, covering 100% of soil surface), T3 (half plastic film mulching, covering 50% of soil surface), and T4 (complete plastic film mulching, covering 100% of soil surface). Compared with the control, straw mulching decreased soil temperature and increased soil moisture, whereas plastic film mulching increased both soil temperature and moisture. Accordingly, straw mulching increased annual crop yields over both cycles, while plastic film mulching significantly enhanced annual crop yield over cycle 2. Compared to the no-mulching treatment, all mulching treatments increased soil CO2 emission over both cycles, and straw mulching increased soil CH4 absorption over both cycles, but patterns of soil N2O emissions under straw or film mulching are not consistent. Overall, compared to T1, annual GHG intensity was significantly decreased by 106%, 24% and 26% under T2, T3 and T4 over cycle 1, respectively; and by 20%, 51% and 29% under T2, T3 and T4 over cycle 2, respectively. Considering the additional cost and environmental issues associated with plastic film mulching, the application of straw mulching might achieve a balance between food security and GHG emissions in the Chinese Loess Plateau. However, further research is required to investigate the perennial influence of different mulching applications.
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•Crop yields were significantly increased by straw mulching over both cycles, and by plastic film mulching in cycle 2.•Both straw and film mulching significantly increased soil CO2 emission over both cycles.•Patterns of soil N2O emissions under straw or film mulching are not consistent.•Both straw and film mulching significantly decreased annual GHGI.•Straw mulching is recommended in Loess Plateau, China.
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