Owing to the presence of a substantial concentration of chlorine in seawater, the anode still faces severe chlorine corrosion, especially the water splitting operated at high current densities. ...Herein, the cost‐effective and scalable NiFe layered double hydroxides with carbonate intercalation (named as NiFe LDH_CO32−) are synthesized utilizing the etching‐hydrolysis and ion exchange strategies under ambient conditions. Experimental findings demonstrate that NiFe LDH_CO32− shows excellent stability at 500 and 1000 mA cm−2 for 1000 h under alkaline simulated seawater. Additionally, a two‐electrode system offers great stability at current densities ranging from 100 to 1000 mA cm−2 over a duration of 400 h in alkaline seawater. This remarkably catalytic stability can be ascribed to the etching‐hydrolysis and carbonate intercalation strategies. The etching‐hydrolysis strategy leads to an integrated electrode for the catalyst‐carrier, enhancing the adhesion between them, and retarding hence the divorce of catalysts from the carrier. Theoretical calculations suggest that the carbonate intercalation weakens the adsorbability of chlorine on catalysts and hinders the coupling of metal atoms with chlorine, thereby impeding the anode corrosion caused by chlorine and improving catalytic stability. More importantly, this strategy has been extended to the preparation of other layered double hydroxides with carbonate intercalation.
In this work, carbonate intercalation and etching‐hydrolysis strategies at room temperature and atmospheric pressure are deployed to synthesize the large‐scale and ultra‐stable electrodes for seawater splitting. The as obtained material (NiFe LDH_CO32−) exhibits impressive OER activity under alkaline simulated seawater, showing stable operation for 1000 h at 500 and 1000 mA cm−2.
Visible light communication (VLC) using light-emitting-diodes (LEDs) has been a popular research area recently. VLC can provide a practical solution for indoor positioning. In this paper, the impact ...of multipath reflections on a two-dimensional indoor VLC positioning is investigated, considering a complex indoor environment with walls, floor, and ceiling. For the proposed positioning system, an LED bulb is the transmitter and a photo-diode is the receiver to detect received signal strength information. Combined deterministic and modified Monte Carlo method is applied to compute the impulse response of the optical channel. Since power attenuation is applied to calculate the distance between the transmitter and receiver, the received power from each reflection order is analyzed. The positioning errors are further estimated for all the locations over the room and compared with the previous works where no reflections considered. Finally, calibration approaches are proposed to decrease the effect of multipath reflections.
•The parameters of vertically layered soils are upscaled for Green–Ampt model.•The p-order power means of parameters capture the overall infiltration behavior well.•Same total infiltration time was ...proposed to obtain optimal p-order power.•Harmonic mean of hydraulic conductivity is one viable upscaled effective Green–Ampt parameter.•The structure of layered soils influences upscaling results significantly.
While Green–Ampt model has been widely used in infiltration calculations through unsaturated soils, upscaling this model for applications in heterogeneous formations remains difficult. In this study, how to upscale soil parameters in the Green–Ampt model for vertically layered soils is examined. The main idea of upscaled effective parameters is to capture infiltration behavior in layered soil formations using only one set of parameters derived from the parameters of individual layers, such that the layered system can be replaced by an equivalent homogeneous medium. The general p-order power mean was proposed to represent the upscaling schemes of the Green–Ampt model. The optimal p value was determined by a general requirement of same total infiltration time for the layered formation and the equivalent homogeneous medium. The p-order power mean for the Green–Ampt parameters can capture the infiltration rates in the layered formations well, illustrating that the proposed upscaling schemes are reasonable to represent the overall behaviors of the heterogeneous layered formations. The structure of layered formations can significantly influence the upscaling results. However, when the number of layers becomes large, the layered formations tend to show homogeneity and the layer structure becomes less important. The results demonstrated that the scheme based on the harmonic mean for the saturated hydraulic conductivity and the general p-order power mean for the wetting front suction head can well capture the overall infiltration behaviors in both the coarse-layer-on-top and fine-layer-on-top formations, and thus is recommended as a general upscaling scheme when using the upscaled Green–Ampt model in layered formations.
Explosive developments in modern society bring huge fire loads. Previous fire detections at early stages are basically enabled by recognizing abnormal high‐temperatures, smoke particles, and flame ...light signals. However, the identification of these characteristic signals is generally accompanied by an open flame or smoke, which makes it difficult to prevent further serious damage. Herein, a latent‐fire‐detecting strategy of trace ammonia (NH3) analysis based on nanohybrid Ti3C2Tx MXene/MoS2 is proposed. Benefiting from nanoscale high‐density Schottky heterojunctions between MoS2 and Ti3C2Tx MXene, ultrafast (3 s @100 ppm), sub‐ppm (200 ppb minimum), and high‐sensitivity (81.7% @100 ppm and 10.2% @200 ppb) detection of NH3 are enabled. An assembled latent‐fire‐detecting olfactory system (LFOS) based on MXene/MoS2 and interdigital electrodes can monitor trace NH3 releases from different materials (wool, leather, foam, and nylon) during thermal decomposition at latent stages. Notably, the LFOS can detect fire threats at least 84 s earlier than commercialized smoke detectors, providing more fire dealing time and an escape period; this offers a promising latent‐fire‐warning approach for eliminating fire treats at an early stage.
Inspired by the significant contributions of micro/nanoscale Schottky heterojunctions to enhancing gas‐sensing performances, here, a new assembled latent‐fire‐detecting olfactory system (LFOS) based on Ti3C2Tx/MoS2 and interdigital electrodes is developed for recognizing trace NH3 volatiles. The LFOS can detect fire threats at least 84 s earlier than commercialized smoke detectors, significantly increasing the fire dealing time and escape period.
In this work, laminated ammonium perchlorate-based composite (LAPC) with high thermal decomposition performance was prepared by ice-template freezing-induced assembly strategy. Cobalt-Konjac ...glucomannan (Co
2+
-KGM) hydrosol with rich AP embedded was designed and used as a frozen precursor. LAPC was obtained from the ice-template freezing of the hydrosol precursor and crystallization of AP molecules. The structure and morphology of as-obtained composite were characterized, and the thermal decomposition performances were investigated. The results showed that LAPC materials have micro-/nano-lamellar structures with the thickness size of 20 μm, which are composed of AP micro-/nanoparticles formed in the freezing crystalline progress and uniformly dispersed Co
2+
-KGM coated on the surface and inside of the micro-/nanoparticles. Thermal analysis results show that LAPC-2 has a lower decomposition temperature than raw AP, which have decreased by 114.3 °C. The activation energy of LAPC-2 thermal decomposition was reduced by 87 kJ/mol from 200 kJ/mol of AP to 113 kJ/mol of LAPC-2. A possible catalytic mechanism of thermal decomposition of LAPC is proposed. Under heating condition, the Co
2+
-KGM molecules firstly decomposed, and Co-based oxides can be in situ generated on the surface and inside of AP particles, resulting in enhancing the catalytic contact areas. Abundant distributed nanoscale Co-based oxides boosted the thermal decomposition of AP and exhibited excellent catalytic performances.
Graphic abstract
Abstract
Age-related osteoporosis is characterized by the deterioration in bone volume and strength, partly due to the dysfunction of bone marrow mesenchymal stromal/stem cells (MSCs) during aging. ...Alpha-ketoglutarate (αKG) is an essential intermediate in the tricarboxylic acid (TCA) cycle. Studies have revealed that αKG extends the lifespan of worms and maintains the pluripotency of embryonic stem cells (ESCs). Here, we show that the administration of αKG increases the bone mass of aged mice, attenuates age-related bone loss, and accelerates bone regeneration of aged rodents. αKG ameliorates the senescence-associated (SA) phenotypes of bone marrow MSCs derived from aged mice, as well as promoting their proliferation, colony formation, migration, and osteogenic potential. Mechanistically, αKG decreases the accumulations of H3K9me3 and H3K27me3, and subsequently upregulates BMP signaling and
Nanog
expression. Collectively, our findings illuminate the role of αKG in rejuvenating MSCs and ameliorating age-related osteoporosis, with a promising therapeutic potential in age-related diseases.
Spin-momentum locked surface states in topological insulators (TIs) provide a promising route for achieving high spin-orbit torque (SOT) efficiency beyond the bulk spin-orbit coupling in heavy metals ...(HMs). However, in previous works, there is a huge discrepancy among the quantitative SOTs from TIs in various systems determined by different methods. Here, we systematically study the SOT in the TI(HM)/Ti/CoFeB/MgO systems by the same method, and make a conclusive assessment of SOT efficiency for TIs and HMs. Our results demonstrate that TIs show more than one order of magnitude higher SOT efficiency than HMs even at room temperature, at the same time the switching current density as low as 5.2×10^{5} A cm^{-2} is achieved with (Bi_{1-x}Sb_{x})_{2}Te_{3}. Furthermore, we investigate the relationship between SOT efficiency and the position of Fermi level in (Bi_{1-x}Sb_{x})_{2}Te_{3}, where the SOT efficiency is significantly enhanced near the Dirac point, with the most insulating bulk and conducting surface states, indicating the dominating SOT contribution from topological surface states. This work unambiguously demonstrates the ultrahigh SOT efficiency from topological surface states.
The ethanol precipitation method has been widely-used for Dendrobium officinale polysaccharides preparation. However, the alcohol-soluble fractions have always been ignored, which causes significant ...wastes of resources and energies. In this study, the extraction, physicochemical properties, and immune regulation activity of an edible D. officinale polysaccharide (DOPs) isolated from the supernatant after 75% ethanol precipitation were systematically investigated. The structural characteristics determination results showed that DOPs was mainly composed of glucose and mannose at a molar ratio of 1.00:5.78 with an average molecular weight of 4.56 × 103 Da, which was made up of α-(1,3)-Glcp as the main skeleton, and the α-(1,4)-Glcp and β-(1,4)-Manp as the branches. Subsequently, the cyclophosphamide (CTX)-induced immunosuppressive mice model was established, and the results demonstrated that DOPs could dose-dependently protect the immune organs against CTX damage, improve the immune cells activities, and promote the immune-related cytokines (IL-2, IFN-γ and TNF-α) secretions. Furthermore, DOPs treatment also effectively enhanced the antioxidant enzymes levels (SOD, GSH-Px) in sera and livers, therefore weakening the oxidative damage of CTX-treated mice. Considering these above data, DOPs presented great potential to be explored as a natural antioxidant and supplement for functional foods.
This study aimed to determine long non‐coding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) expression in pancreatic cancer and to explore the potential molecular actions of SNHG14 in ...mediating pancreatic cancer progression. Gene expression was detected by quantitative real‐time PCR. Cell proliferation, growth and invasion were detected by respective CCK‐8, colony formation, and transwell invasion assays. Protein levels were measured by Western blotting. Cell apoptosis and caspase‐3 activity were detected by flow cytometry and caspase‐3 activity assay. The link between miR‐613 and its targets was evaluated by luciferase reporter assay. In vivo tumour growth was evaluated using a xenograft model of nude mice. SNHG14 expression was up‐regulated in cancerous tissues from pancreatic cancer patients. High expression of SNHG14 was associated with poor tumour differentiation, advanced TNM stage and nodal metastasis. SNHG14 overexpression enhanced cell proliferative, growth and invasive abilities, and suppressed apoptotic rates and caspase‐3 activity in pancreatic cancer cells, while SNHG14 knockdown exerted opposite effects. Mechanistic studies revealed that miR‐613 was targeted by SNHG14, and Annexin A2 (ANXA2) was targeted and inversely regulated by miR‐613 in pancreatic cancer cells. In vivo studies showed that SNHG14 knockdown attenuated tumour growth. MiR‐613 was down‐regulated and ANXA2 was up‐regulated in the pancreatic cancer tissues, and SNHG14 expression levels were inversely correlated with miR‐613 expression levels and positively correlated with the ANXA2 mRNA expression levels. Collectively, our results suggest that SNHG14 potentiates pancreatic cancer progression through modulation of annexin A2 expression via acting as a competing endogenous RNA for miR‐613.
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