Search

Cross-border e-commerce, as a new form of trade driven by digital technology, provides an opportunity to enhance the entrepreneurial vitality of cities. With the help of the comprehensive pilot area for cross-border e-commerce, also called a "quasi-natural" experiment, and using 2010–2020 panel data and Chinese business enterprise registration data for 278 cities in China, this paper examined the impact of cross-border e-commerce on enterprise vitality. The study found that the pilot policy in the comprehensive pilot area promoted the entrepreneurial vitality to increase by about 13.3%, and it remained stable after a series of tests. The heterogeneity analysis shows that the pilot policies in the comprehensive pilot areas have a stronger effect on the promotion of enterprise vitality in the eastern and western regions. At the same time, the pilot policy has expanded the scope of enterprise subjects and plays a more prominent enterprise incentive effect in small and medium-sized cities, cities with low innovation, and small and medium-sized registered enterprises. In addition, the pilot policy stimulates the entrepreneurial vitality of the service industry, but has no significant impact on agriculture and manufacturing. In terms of the influence mechanism, the comprehensive pilot area mainly affects the entrepreneurial vitality by means of optimizing the business environment, reducing the entry cost, promoting the synergistic agglomeration of manufacturing and producer services, and stimulating market demand. The further spatial spillover effect found that the comprehensive pilot area not only improves the entrepreneurial vitality of the pilot cities, but also radiates the enterprise development of neighboring and surrounding cities with similar economic development. [ABSTRACT FROM AUTHOR]

In this study, we have developed a novel approach for synergistic tumor treatment by utilizing degradable dendritic mesoporous silica nanoparticles loaded with doxorubicin and curcumin (Cur). These nanoparticles are equipped with polydopamine (PDA) for photothermal therapy and hyaluronic acid (HA) as a targeting ligand. The incorporation of PDA not only ensures the controlled release of therapeutic agents but also confers pH and photothermal responsiveness to the nanocarriers. Cur, a natural compound, serves as an antitumor sensitizer, elevating intracellular ROS levels to promote apoptosis. In addition, the excellent biocompatibility and targeting property of nanocarriers were enhanced by the HA‐modification, improving the effective accumulation in tumor cells. Comprehensive research including MTT assay, live/dead staining and ROS generation proved that the excellent antitumor capability of dual‐drug loaded nanocarriers was a result of chemo‐photothermal synergistic therapy and Cur‐induced cellular amplified ROS generation. The cellular uptake assays further demonstrated the efficiency of HA‐mediated intracellular accumulation, accelerated uptake driven by photothermal‐induced and a precise internalization pathway of nanocarriers. Furthermore, the results of in vivo biocompatibility revealed no significant blood and organ toxicity associated to the prepared nanocarriers. Our findings underscore the substantial potential of the proposed dual‐drug loaded nanocarriers for chemo‐photothermal synergistic therapy, offering a safe and promising strategy for effective tumor treatment. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is an obligate parasitic protozoon that transmits to animals and humans via ingested food. Cats that act as T. gondii's final hosts play a critical role in T. gondii transmission by shedding millions of oocysts. Timely diagnosis of infected cats is essential for preventing toxoplasmosis because oocysts are a putative T. gondii source in epidemiology. We developed a new visual LAMP assay targeting the B1 gene to analyze single oocysts in cat feces in this study. The amplification result could be visually estimated based on the color change. LAMP assay analytical sensitivity was 101 copies/µL for the B1 gene plasmid, which was tenfold better than the PCR reaction. There were no cross-reactions with other parasites. The LAMP assay can detect a single T. gondii oocyst in 200 mg of cat feces. The LAMP assay detected a single oocyst in 200 mg cat feces at a higher rate than the PCR assay (83.3% vs. 50.0%). [ABSTRACT FROM AUTHOR]

Highlights: The loss mechanisms of irreversible Li in electrolytes with various salts (e.g., lithium hexafluorophosphate (LiPF6), lithium difluoro(oxalato)borate (LiDFOB), and lithium bis(fluorosulfonyl)amide (LiFSI)) are systemically revealed. A universal procedure for the electrolyte design of Li metal batteries is proposed: (i) decouple and find the main reason for the irreversible Li loss; (ii) add the corresponding electrolyte additive. Lithium (Li) metal electrodes show significantly different reversibility in the electrolytes with different salts. However, the understanding on how the salts impact on the Li loss remains unclear. Herein, using the electrolytes with different salts (e.g., lithium hexafluorophosphate (LiPF6), lithium difluoro(oxalato)borate (LiDFOB), and lithium bis(fluorosulfonyl)amide (LiFSI)) as examples, we decouple the irreversible Li loss (SEI Li+ and "dead" Li) during cycling. It is found that the accumulation of both SEI Li+ and "dead" Li may be responsible to the irreversible Li loss for the Li metal in the electrolyte with LiPF6 salt. While for the electrolytes with LiDFOB and LiFSI salts, the accumulation of "dead" Li predominates the Li loss. We also demonstrate that lithium nitrate and fluoroethylene carbonate additives could, respectively, function as the "dead" Li and SEI Li+ inhibitors. Inspired by the above understandings, we propose a universal procedure for the electrolyte design of Li metal batteries (LMBs): (i) decouple and find the main reason for the irreversible Li loss; (ii) add the corresponding electrolyte additive. With such a Li-loss-targeted strategy, the Li reversibility was significantly enhanced in the electrolytes with 1,2-dimethoxyethane, triethyl phosphate, and tetrahydrofuran solvents. Our strategy may broaden the scope of electrolyte design toward practical LMBs. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is an obligate parasitic protozoon that transmits to animals and humans via ingested food. Cats that act as T. gondii's final hosts play a critical role in T. gondii transmission by shedding millions of oocysts. Timely diagnosis of infected cats is essential for preventing toxoplasmosis because oocysts are a putative T. gondii source in epidemiology. We developed a new visual LAMP assay targeting the B1 gene to analyze single oocysts in cat feces in this study. The amplification result could be visually estimated based on the color change. LAMP assay analytical sensitivity was 101 copies/µL for the B1 gene plasmid, which was tenfold better than the PCR reaction. There were no cross-reactions with other parasites. The LAMP assay can detect a single T. gondii oocyst in 200 mg of cat feces. The LAMP assay detected a single oocyst in 200 mg cat feces at a higher rate than the PCR assay (83.3% vs. 50.0%). [ABSTRACT FROM AUTHOR]

Pullout tests were performed on ordinary concrete (OC) specimens and basalt fiber–reinforced concrete (BFRC) specimens after exposure to high temperatures (20°C, 100°C, 300°C, 500°C, and 700°C). The effect of temperature on the bond property between rebars and concrete was studied. The measured data indicated that temperature below 300°C generates little damage to the bond performance for both OC and BFRC, while a temperature exceeding 500°C leads to sharp deterioration, which is similar to the changing pattern of concrete strength. The deterioration degree of bond strength and bond stiffness of BFRC specimens after exposure to high temperatures is lower than that of OC, while the deformation ability is better. In the end, a practical bond strength–slip constitutive model was established, taking account of the temperature in coefficients. [ABSTRACT FROM AUTHOR]

The issue of low compressive strength in concrete is primarily caused by the antiwashout admixture (AWA) added to cement-based cementitious material (CBCM). In this work, the AWA was added to alkali-activated cementitious material (AACM) to prepare underwater non-dispersible concrete (UNDC). The effect of different AWA contents on the compressive strength of AACM was studied by measuring the compressive strength, hydration process, pore structure, microscopic appearance and chemical composition. The results show that the compressive strength of AACM-UNDC moulded underwater can reach higher than 80% of the compressive strength of AACM-UNDC moulded on land. The polymerisation and decomposition reaction of AACM can lead to the formation of strong covalent bonds, which can not only interweave with the long chain structure of AWA to form a dense network structure but also avoid the AWA wrapping on the surface of the activated material through the charge effect, and hinder the hydration reaction process of AACM. [ABSTRACT FROM AUTHOR]

Background: Toxoplasma gondii is an opportunistic protozoan that is ubiquitous in humans and animals. It can invade any human organ and cause severe diseases, including toxoplasma ophthalmopathy, meningoencephalitis, and liver necrosis. Porcine toxoplasmosis is prevalent in China. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) and Cas (CRISPR-Associated Protein) systems are widely used for gene editing and pathogen detection. CRISPR-based diagnostics are molecular assays that have been developed to detect parasites with high sensitivity and specificity. Methods: This study aimed to establish a combined CRISPR/Cas12a and RPA rapid detection method for T. gondii by targeting the B1 gene and 529 bp repeat element (529 RE). The detection results could be visualized by the fluorescence or lateral flow strips (LFS). The sensitivity and specificity of the method were evaluated, and T. gondii-infected mouse blood was used for detection. Results: The results indicated that the established method for T. gondii detection was satisfactory, with a detection limit of 1.5 cp/μl for the two loci. Moreover, the B1 gene could detect 1 tachyzoite per reaction, and the 529 RE could detect 0.1 tachyzoite per reaction, consistently with the highly sensitive nested polymerase chain reaction (PCR) results. The method was suitable for strains, including RH, and did not cross-react with other protozoa DNA with similar habits. The T. gondii-infected mouse blood samples were all positive for T. gondii at 1, 3, and 5 days post infection (dpi). Conclusions: This study established a rapid, sensitive, and time-saving DNA detection method for T. gondii that has the potential to be an alternative tool for T. gondii detection in the field. [ABSTRACT FROM AUTHOR]

In order to increase the content of mineral admixtures in cement, this study proposes a method for preparing a high-volume mineral admixture cementitious material (HMAC) using superfine cement as a reverse filling material. Firstly, superfine cement is prepared through mechanical grinding. Then, the activity of mineral admixtures (such as slag and fly ash) is enhanced by mechanical grinding, sulfate activation, and alkali activation methods. Meanwhile, the evolution of HMCM from microstructure to macroscopic mechanical behavior is studied by combining a laser particle size analyzer and a scanning electron microscope. Furthermore, the reverse filling mechanism of superfine cement on mineral admixtures under different activation conditions is proposed. Results show that superfine cement can largely improve the utilization rate of cement clinker and the compressive strength of cementitious materials. In the condition that the compressive strength is not lower than that of the control group (without mineral admixture), the content of mineral admixture can be increased to 50%, 70%, and 90% after mechanical grinding, sulfate activation, and alkali activation, respectively. Analysis indicates that the reverse filling effect of superfine cement is the main reason for improving the density of the HMCM. [ABSTRACT FROM AUTHOR]

Recruiting anions from electrolyte additives into the lithium ion solvation structure is a promising strategy for the construction of long‐lifespan Li‐metal batteries (LMBs). However, inadequate understanding of the anion‐involved Li+ solvation hinders the finding of new anion additives. Herein, using NO3− as an example, the effects of the newly‐introduced anion on the Li+ solvation structure are investigated. It is demonstrated that the added NO3− reduces the electrostatic potential of the Li+ solvation cluster, especially for solvated solvents, which improves electrolyte stability against the Li anode. However, such a conclusion is not universal for all anion additives. It is also confirmed that the anions with higher binding energy and smaller ion size are more apt to improve the Li stability and reversibility. Based on the above understanding, a new selection principle based on anion selection coefficient (the rate of the anion size to the binding energy toward Li+, unit: Å3 eV−1) is proposed, and with which a new hexafluorosilicate anion is found to be beneficial to LMBs. [ABSTRACT FROM AUTHOR]

We introduce a facile strategy to greatly improve the electrochemical reversibility of cobalt‐free cathode material by doping trace quantity of aluminum (Al) in LiNi0.65Mn0.35O2. X‐ray diffraction and X‐ray photoelectron spectroscopy results reveal that Al doping reduces the cation disorder consequently and hence increases structural stability. Electrochemical measurements show that rate capability and cycling stability are remarkably enhanced by Al doping. Al‐doped LiNi0.65Mn0.35O2 exhibits the optimized electrochemical performance with a capacity retention of 94.2 % after 200 cycles at 2 C in voltage range of 2.75–4.2 V in cylindrical full cell, demonstrating that Al‐doped cathode exhibits enhanced cyclability, reduced polarization and high‐rate capability during charge/discharge process. Moreover, the full cell shows good low‐temperature performance with more than 70 % capacity retention at −20 °C. The improved performances can be ascribed to the enhanced stability in layered structure of the Co‐free material by the support of doped Al ions. [ABSTRACT FROM AUTHOR]

To accurately reflect the movement of humans or robots, multi-sensor integration strategy is necessary to decouple complex deformations caused by motion in the wearable artificial kinesthetic perception system. The multi-sensor integration strategy could collect multi-dimension information, making up for the deficiency of robustness and accuracy of single sensor in complex motion scenes and extending the sensing capability of the system. However, the inevitable inconsistency between multiple sensors causes difficulties in fabrication, integration, and perception, limiting the development of artificial kinesthetic perception systems toward the direction of compact integration, large-area sensing, and high-resolution decoupling. Here, we propose a strategy to build an artificial kinesthetic perception system based on the differential design of homogeneous sensors. The strategy aims at guiding system design to avoid the inconsistency in multi-sensor integration by revealing the explicit relationship among structure, signal, and movements from the perspective of the physics model. According to the strategy, we presented a simple fabrication method of the kinesthetic perception prototype. The prototype with two homogenous sensors (0.019 56 residual on average) shows three differential signal modes to three deformations. With the help of machine learning, it realized the decoupling task to 25 kinds of complex deformations. The accuracy remains at 95% even though the decoupling resolution is up to 0.2 mm. With more than one prototype arrayed, complex deformation composed with more kinds of basic deformation (shear and twist) could be further decoupled. We believe that the strategy described in this paper will contribute to the development of a compact and programmable kinesthetic perception system. [ABSTRACT FROM AUTHOR]

S2−-enriched alkali-activator (SEAA) was prepared by modifying the alkali activator through Na2S. The effects of S2−-enriched alkali-activated slag (SEAAS) on the solidification performance of Pb and Cd in MSWI fly ash were investigated using SEAAS as the solidification material for MSWI fly ash. Combined with microscopic analysis through scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), the effects of SEAAS on the micro-morphology and molecular composition of MSWI fly ash were studied. The solidification mechanism of Pb and Cd in S2−-enriched alkali-activated MSWI fly ash was discussed in detail. The results showed that the solidification performance for Pb and Cd in MSWI fly ash induced by SEAAS was significantly enhanced first and then improved gradually with the increase in dosage of ground granulated blast-furnace slag (GGBS). Under a low GGBS dosage of 25%, SEAAS could eliminate the problem of severely exceeding permitted Pb and Cd in MSWI fly ash, which compensated for the deficiency of alkali-activated slag (AAS) in terms of solidifying Cd in MSWI fly ash. The highly alkaline environment provided by SEAA promoted the massive dissolution of S2− in the solvent, which endowed the SEAAS with a stronger ability to capture Cd. Pb and Cd in MSWI fly ash were efficiently solidified by SEAAS under the synergistic effects of sulfide precipitation and chemical bonding of polymerization products. [ABSTRACT FROM AUTHOR]

To disclose influences of ultrasonic vibration agitation on the carbonation resistance of cement-based materials after absorption of CO2, the variation laws in internal carbonization zone were explored by the testing carbonization depth and carbonization range (pH variation range) of cement mortar after CO2 absorption at different ages. Results demonstrated that when CO2 absorption volumes of the cement mortar before carbonization were 0.44%, 0.88%, 1.32%, 1.76%, and 2.20% (28 d), the carbonization depth under ultrasonic vibration decreased by 5.5%, 12.3%, 21.7%, 20.7%, and 26.7% compared to those under mechanical stirring, respectively. When the ultimate CO2 absorption volume increased to 2.2% of cement mass, the extended degree of cement mortar was 103.23 mm, which decreased by 5.4% compared to that before CO2 absorption. pH variation values of the carbonization range under ultrasonic vibration presented a rising trend with the increase of CO2 absorption volume of cement mortar before carbonation. This indicated that, with the increase of CO2 absorption volume of cement mortar before carbonation increases under ultrasonic vibration, the carbonization process of the hardened body of cement mortar might be decelerated to some extent. Additionally, changes in internal composition and physical images of cement-based materials after absorption of CO2 were analyzed through microtest means like SEM and XRD. A carbonation resistance model was constructed, thus enabling disclosure of the variation mechanism of carbonation resistance of cement-based materials after absorption of CO2 under mechanical stirring and ultrasonic vibration. Results demonstrated that the higher CO2 absorption volume of fresh slurry generated more "nano-level" CaCO3 crystal nucleus. Accordingly, it could improve the porous structure of the cement mortar, decrease the quantity of capillary tubes significantly, improve the compaction degree of cement-based materials effectively, and lower the diffusion rate of CO2 in the cement paste base, thus improving the carbonation resistance. Research conclusions have important significance to decrease CO2 emissions and improve carbonation resistance of concrete. [ABSTRACT FROM AUTHOR]

In this investigation, non-spontaneous combustion coal gangue was activated by two methods: (1) low-temperature calcination and (2) calcium addition. Differences in the activity of the activated coal gangue were studied at various calcination temperatures and amounts of calcium addition. Meanwhile, the cementation activity of the activated coal gangue was evaluated according to the activity effect analysis. Furthermore, the influences of the activated coal gangue on the cementation activity of cement were investigated. The results indicated that the activities of the activated coal gangue increased at a temperature between 500 °C and 700 °C. The calcium addition method can also increase the activity of coal gangue, with the effect being better when the gangue is mixed with slag. The addition of calcium and the calcination of coal gangue can promote the production of active minerals such as metakaolin, which is the main reason for the increased cementation activity. [ABSTRACT FROM AUTHOR]

The use of non‐solvating, or as‐called sparingly‐solvating, electrolytes (NSEs), is regarded as one of the most promising solutions to the obstacles to the practical applications of Li−S batteries. However, it remains a puzzle that long‐life Li−S batteries have rarely, if not never, been reported with NSEs, despite their good compatibility with Li anode. Here, we find the capacity decay of Li−S batteries in NSEs is mainly due to the accumulation of the dead Li2S at the cathode side, rather than the degradation of the anodes or electrolytes. Based on this understanding, we propose an electrochemical strategy to reactivate the accumulated Li2S and revive the dead Li−S batteries in NSEs. With such a facile approach, Li−S batteries with significantly improved cycling stability and accelerated dynamics are achieved with diglyme‐, acetonitrile‐ and 1,2‐dimethoxyethane‐based NSEs. Our finding may rebuild the confidence in exploiting non‐solvating Li−S batteries with practical competitiveness. [ABSTRACT FROM AUTHOR]

The use of non‐solvating, or as‐called sparingly‐solvating, electrolytes (NSEs), is regarded as one of the most promising solutions to the obstacles to the practical applications of Li−S batteries. However, it remains a puzzle that long‐life Li−S batteries have rarely, if not never, been reported with NSEs, despite their good compatibility with Li anode. Here, we find the capacity decay of Li−S batteries in NSEs is mainly due to the accumulation of the dead Li2S at the cathode side, rather than the degradation of the anodes or electrolytes. Based on this understanding, we propose an electrochemical strategy to reactivate the accumulated Li2S and revive the dead Li−S batteries in NSEs. With such a facile approach, Li−S batteries with significantly improved cycling stability and accelerated dynamics are achieved with diglyme‐, acetonitrile‐ and 1,2‐dimethoxyethane‐based NSEs. Our finding may rebuild the confidence in exploiting non‐solvating Li−S batteries with practical competitiveness. [ABSTRACT FROM AUTHOR]

The over‐burnt free‐CaO(f‐CaO) existential state in hot‐splashed steel slag is understood by observing the microstructure of steel slag section and analyzing the minerals in the steel slag (SS). In the investigation, a new method of using hydrochloric acid as the solvent to modify the steel slag powder (SSP) is put forward. The effects of hydrochloric acid pretreatment on the surface morphology of SS and the hydration activity and soundness of SSP blended cement are investigated. Furthermore, the failure mechanism of steel slag cement‐based materials and the hydration mechanism of acid‐activated steel slag (ASS) are discussed in detail. The research indicated that the optimum dosage of modified SSP is 20 wt%. At this dosage, the 7‐ and 28‐day compressive strength of paste is nearly increased 15% compared with the untreated steel slag cement‐based mortar specimens. Moreover, the acid activated SS‐blended cement pastes show much better soundness performances after autoclaved curing tests when compared with corresponding pastes with SS without treatment. It provides a promising approach for efficient and safe utilization of SS as supplementary cementitious material. [ABSTRACT FROM AUTHOR]

In order to make the precast concrete reach the design strength quickly, by increasing the active silicon content of the precast concrete, the influence mechanism of the active silicon on the early compressive strength of the precast concrete was studied. The early hydration process, early pore structure, and chemical composition of precast concrete mixed with different types and dosages of water‐soluble active silicon materials (WASM) were characterized through heat of hydration test, mercury intrusion porosimetry (MIP), X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT‐IR). The increase of active silicon content in precast concrete can greatly improve the early compressive strength of precast concrete (PC) under steam curing conditions. The increase of active silicon content in PC can greatly improve the early hydration process of cement and accelerate the rate of early cement hydration heat release. The addition of active silicon in the early stage of cement hydration can promote the rapid conversion of Ca(OH)2 generated in the gelling system to high‐strength CSH gel. A large amount of high‐strength CSH gel is formed in the early stage of cement hydration, which can promote the formation of a dense internal structure of PC as soon as possible, thereby promoting the rapid improvement of the early compressive strength of PC. [ABSTRACT FROM AUTHOR]

In this study, dehydrated cement paste (DCP) was used as a calcium source and solid dispersant for alkali-activated coal gangue (CG). The reaction mechanism of alkali-activated CG-DCP was revealed by detecting the compressive strength and microscopic properties of alkali-activated CG-DCP. The molecular structure characteristics of alkali-activated CG-DCP combined with the molecular dynamics were analysed. The results show that using DCP as the solid dispersant of CG could refine the particle size of CG, and improve problems of bonding and uneven distribution of particles caused by grinding. The addition of DCP could increase the calcium content in alkali-activated CG-DCP and promote the generation of more calcium silicate hydrate gel, thereby increasing its compressive strength. The secondary calcination of the CG-DCP composites could promote the release of calcium in the composites and increase the attraction force between particles in the alkali-activated CG-DCP molecular structure. The secondary calcination temperature of more than 900°C can lead to attraction force decrease and molecular structure instability in the molecular structure of alkali-activated CG-DCP, resulting in decreasing compressive strength. [ABSTRACT FROM AUTHOR]

This study focuses on overcoming the agglomeration issue of nano-SiO2 powder in cement, facilitating the strengthening mechanism of cement-based materials. A nano-SiO2 precursor solution (NSPS) was added to cement-based materials to replace nano-SiO2 powder. The influencing laws of the alkalinity and dosage of the NSPS on the mechanical properties of cement were investigated. Further, the strengthening mechanism of the mechanical properties of cement-based materials after internal nano-SiO2 production was analysed. The results show that (1) when the alkalinity of the precursor solution is a weak acid (pH = 6), the compressive strength of cement-based materials after internal nano-SiO2 production is 25%~36% higher than that of pure cement-based materials and 16%~22% higher than that of cement-based materials with silica fume; (2) when the solid content of SiO2 in the current displacement solution is about 0.16% of the cement mass, the compressive strength of the prepared cement-based material is the highest. With the continuous increase in the solid content of SiO2 in the precursor solution, the compressive strength of cement-based materials after internal nano-SiO2 production decreases but is always greater than the compressive strength of the cement-based material mixed with nano-SiO2 micro powder. According to a microstructural analysis, nano-SiO2 particles that precipitate from the precursor solution can facilitate the hydration process of cement and enrich the gel products formed on the cement particle surface. In addition, new network structures among cement particles are formed, and precipitated nano-SiO2 particles fill in the spaces among these cement particles as crystal nuclei to connect the cement particles more tightly and compact the cement-based materials. This reinforces the mechanical properties of cement-based materials. [ABSTRACT FROM AUTHOR]

The issues associated with the fabrication of nano-silica (NS) mineral powder, such as high cost and agglomeration, can be effectively mitigated by using a precursor solution of NS as the external mixture of cement-based materials. Based on the liquid-phase preparation of NS mineral powder, its preparation technology was thoroughly investigated herein. The precursor solution of NS was synthesized using acid media (HCL, HNO3, HBO3, HCOOH, CH3COOH)—the acetic acid concentration was 1~15%—and siliceous materials. (The concentration of sodium silicate was 20~38%). In addition, the pH value (pH4~pH8) of the precursor solution was measured using a pH detector. The indexes of NS, such as precipitation time, morphology, and distribution, were observed to formulate a preparation technique for the precursor solution of NS that possessed the best results for the precipitation of nanoparticles. From the acquired results, it was demonstrated that acetic acid solution (concentration ≤ 3%) and sodium silicate solution (concentration ≤ 25%) were mixed into a solution with pH = 6, which was the optimum mixing ratio for the precursor solution of NS. The prepared precursor solution of NS was also added to the Ca(OH)2 saturated solution, and the precursor solution became active from a stable state. Then, NS particles were precipitated in an alkaline solution and reacted with Ca(OH)2 to form calcium silicate gel, which made the solution increasingly turbid and generated many visible and uniformed flocculating substances. With time, gels were continuously produced, which then turn white. Similarly, NS particles can be precipitated when the precursor solution is added to cement paste, which reacts with the Ca(OH)2 to generate CSH gel and improve the compactness of the cement paste. [ABSTRACT FROM AUTHOR]

In this investigation, a phase change material with a melting temperature of about 450°C (PCM‐45) is prepared and applied to solve microstructure degradation problem of concrete matrix when exposed to temperatures more than 500°C. The morphology changes of PCM‐45 and the improvement effects of PCM‐45 on microstructure of cement matrix are investigated based on microstructure characteristics, ultrasonic pulse velocity of cement paste and compressive strengths of cement mortar with different dosages of PCM‐45 at 500, 600, 700, 800 and 900°C. The results show that morphology of PCM‐45 is changed, indicating that PCM‐45 transforms from solid to liquid phase and that the liquefied PCM‐45 can diffuse at elevated temperatures. When temperature returns to room temperature, the liquefied PCM‐45 becomes solidified, during which process the microstructure of cement matrix is improved. Therefore, compressive strength and ultrasonic pulse velocity of specimens with PCM‐45 are greatly increased compared to those of specimens without PCM‐45. [ABSTRACT FROM AUTHOR]

The synergistic treatment combining chemotherapy and hyperthermy, as a promising strategy, can improve the therapeutic efficiency of tumor therapy. The glutathione-responsive, chemotherapeutic and photothermal synergistic drug delivery systems (DDS) were developed using degradable dendritic mesoporous silica nanoparticles (DDMSNs) as carriers, camptothecin (CPT) as antitumor drug, and bovine serum albumin (BSA)/CuS as photothermal reagents (denoted as DDMSNs-CPT-CuS). BSA/CuS can prevent the premature drug release during the delivery process, and convert light energy into heat under photothermal treatment. The DDMSNs-CPT-CuS composites ranging from 100 to 200 nm had a loading capacity of 150 μg mg−1 for CPT and performed excellent GSH-triggered drug release behavior under condition of pH (5.0) and glutathione (GSH, 10 mM). The photothermal conversion efficiency (η) of DDMSNs-CuS was 38.8% with 808 nm laser irradiation for 10 min (2.5 W cm−2). The engineered DDMSNs-CuS showed the low protein adsorption capacity (140–230 μg mg−1), hemolysis rate of 5% (200 μg mL−1), and weak cytotoxicity for A549 and Hela cells with a cell viability of more than 75% (50 μg mL−1), indicating that the developed drug carriers displayed superior biocompatibility. There were significant differences between the cell viabilities treated with DDMSNs-CPT-CuS under NIR laser irradiation and that of without NIR laser irradiation when the loaded-CPT concentration was more than 6 μg mL−1. The proposed DDMSNs-CPT-CuS exhibited well performances, such as easy preparation, low cytotoxicity and high photothermal conversion efficiency. The results illustrated that DDS can achieve the synergistic treatment of photothermal therapy and chemotherapy for tumor cells. Therefore, this work provides a promising strategy to design multi-responsive and synergistic treatment DDS, and the developed DDMSNs-CPT-CuS present great potential for tumor treatment. [ABSTRACT FROM AUTHOR]

Research shows that ultrasonic vibratory stirring can effectively increase CO2 absorption by cement slurry. However, with the increase in CO2 absorption, the fluidity of slurry begins to decrease. Adding water reducer to fresh cement paste can improve its fluidity. In order to reveal the influences of ultrasonic vibration and water-reducer addition on the rheological properties of cement pastes after absorbing various amounts of CO2, changes in the rheological properties of yield stress and plastic viscosity (PV) were analysed. The results show that ultrasonic vibration can effectively increase the shear stress and PV of cement paste. Moreover, shear stress and PV are positively related to the CO2 absorption amount. Meanwhile, a new rheological model of cement paste carbonated under ultrasonic vibration was established based on the basic principles of rheology. Microstructural changes in cement paste before and after water-reducer addition were observed by scanning electron microscopy (SEM). A microrheological model of cement paste carbonated under ultrasonic vibration and with water reducer added was constructed. It describes the influencing mechanisms of ultrasonic vibration and water-reducer addition on the rheological properties of carbonated cement paste. Next, a molecular model was constructed in which CO2 was added into a C-S-H gel. Changes in intermolecular repulsion in the CO2+ C-S-H gel structure and in the CO2− water-reducer molecular structure were analysed. Finally, the rheological mechanism was further analysed in terms of the dispersion effect of the C-S-H gel. The results will play a major role in improving the fluidity of cement paste. [ABSTRACT FROM AUTHOR]

Drug resistance, either intrinsic or acquired, can impair treatment effects and result in increased cell motility and death. MicroRNA-21 (miR-21), a proto-oncogene, may facilitate the development or maintenance of drug resistance in cancer cells. Restoring drug sensitivity can improve therapeutic strategies, a possibility that requires functional evaluation and mechanistic exploration. For miR-21 detection, matched tissue samples from 30 head and neck squamous cell carcinoma (HNSCC) patients and 8 head and neck cancer (HNC) cell lines were obtained. Reverse transcription-PCR to detect expression, MTT and clonogenic assays to evaluate cell proliferation, apoptosis assays, resazurin cell viability assays, western blot and luciferase reporter assays to detect protein expression, and flow cytometry to analyse the cell cycle were adopted. Compared to the corresponding normal control (NC) tissues, 25 cancer tissues had miR-21 upregulation among the 30 matched pair tissues (25/30, 83.8%); furthermore, among the 8 HNC cell lines, miR-21 expression that was notably upregulated in three: UPCI-4B, UMSCC-1, and UPCI-15B. In both the UMSCC-1 and UPCI-4B cell lines, the miR-21 mimic enhanced cell proliferation with reduced apoptosis and increased viability, whereas the miR-21 inhibitor resulted in the opposite effects (all P<0.001); additionally, miR-21 directly targeted the tumour suppressor phosphatase and tensin homologue (PTEN) and inhibited PTEN expression. Furthermore, the miR-21 mimic induced cisplatin resistance, while the miR-21 inhibitor restored cisplatin sensitivity. Overexpression of miR-21 can enhance cell proliferation, reduce apoptosis, and induce drug resistance by inhibiting PTEN expression. Targeting miR-21 may facilitate cancer diagnosis, restore drug sensitivity, and improve therapeutic effects. [ABSTRACT FROM AUTHOR]

In order to explore the influence of nickel slag powder (Ni) and polypropylene fiber (PP) on the performance of MPKC mortar, different mass fractions of Ni (5%–20%) and different volume fractions (0.6% and 1.0%) of PP were added to MKPC. The composite modified MKPC (CM-MKPC) specimens were tested and analyzed for flexural strength, compressive strength, split tensile strength, and bending performance. With the help of scanning electron microscope, the microstructure and fracture morphology of the modified MKPC specimens for related research. The results show that the addition of PP and Ni improves the mechanical properties of MKPC and improves its flexibility and deformation properties. When the content of Ni and volume of PP are 15% and 1.0%, respectively, the mechanical properties and bending properties of the modified MKPC mortar are the largest in the same group. Ni added to the MKPC gel system can reduce the friction between irregular magnesium oxide particles and between aggregates. In this way, PP fiber can well enter into the aggregate and play a bridging role at the interface, so that MKPC can better play its mechanical properties. [ABSTRACT FROM AUTHOR]

In this paper, the rheological parameters of the alkali-activated slag underwater non-dispersible paste (AAS-UNDP) were tested, and the influence of polyacrylamide (PAM) on the rheological property of AAS-UNDP was studied combing with the method of molecular dynamics simulation. The experimental results show that the rheological model of AAS-UNDP and cement basted underwater non-dispersible paste (CB-UNDP) are consistent with the Herschel-Bulkley model. The results of molecular dynamics simulation show that the anions in PAM and the OH− alkali-activated slag cementitious material (AASCM) can produce repulsive force, so the potential energy of the AASCM is lower than the potential energy of the cement based cementitious material (CBCM).The mean square displacement (MSD) value and self-diffusion coefficient of PAM in the AASCM are higher than those of CBCM, indicating that the diffusion rate of particles in the AASCM is better than that of CBCM. [ABSTRACT FROM AUTHOR]

This study investigated the effect of silicate modulus (M = silicon dioxide (SiO2)/sodium oxide (Na2O) by mass) and activator content S (mass proportion of sodium oxide and silicon dioxide to ground granulated blast-furnace slag (GGBS)) of sodium silicate (SS) solution on the compressive strength of alkali-activated GGBS (AAS) mortars. At a given solid content, the specimens activated by SS with modulus of 1.0 and 1.5 had the highest compressive strength. In the case of the same modulus of SS, the compressive strength of the AAS mortars rose linearly and then remained unchanged or declined slightly with the increase in S. The mechanism of the action of SS on AAS was studied using backscattered electron (BSE) and energy-dispersive spectroscopy (EDS). The BSE image of AAS shows that GGBS particles are tightly bonded to the surrounding hardened, jelly-like slurry, and that the structure of the GGBS particles in the AAS slurry is intact without an apparent hydrating layer around it. EDS analysis revealed that only active materials in the GGBS, mainly calcium, are dissolved to participate in reaction, and that dissolving these materials does not damage the GGBS structure. S is solidified by these active materials, which embed the GGBS particles therein to form a whole. [ABSTRACT FROM AUTHOR]

To realize high-efficiency CO2 absorption by fresh cement paste, ultrasonic vibration technology is introduced into the CO2 absorption test device used in this study. Influences of ultrasonic frequency on the CO2 absorption rate (CO2 AR) and the ultimate absorption amount of fresh cement paste are analyzed. Furthermore, the influencing laws of the CO2 absorption amount (CO2 AA) on the fluidity, pore distribution, and mechanical properties of cement paste under ultrasonic vibrating agitation are analyzed by measuring the variations of the CO2 AA of cement paste. Results demonstrate that ultrasonic vibrating agitation not only can increase the CO2 AR and ultimate absorption amount of fresh cement paste, but also can optimize the internal pore structure of materials and compressive strength of cement-based materials. [ABSTRACT FROM AUTHOR]

This study describes a simple method for the large‐scale isolation of pure Toxoplasma gondii tachyzoites and bradyzoites. T. gondii tachyzoites were obtained from infected human foreskin fibroblasts (HFFs) and peritoneal exudates of mice, while tissue cysts containing bradyzoites were collected from chronically infected mice. Harvested cells and brain tissues were incubated in Hanks balanced salt solution (HBSS), containing 0.25% trypsin and 0.5% taurodeoxycholic acid (TDC) for 5 min. Subsequent washes in phosphate buffered saline (PBS) were conducted, and the cell viability of the preparations was good, as determined by flow cytometry and ability to reinfect HFF cells and propagate in mice. The purification procedure allowed for a rapid preparation of pure T. gondii tachyzoites and bradyzoites in sufficient quantity that can be used for downstream procedures. The advantage of the new method is that it is convenient and inexpensive. [ABSTRACT FROM AUTHOR]

The preparation of alkali-activated materials from red mud for building materials is a promising way to solve the environmental pollution caused by red mud. However, the low compressive strength of alkali-activated red mud-based materials is the biggest obstacle to this solution. In this paper, we illustrate that the compressive strength of alkali-activated red mud and blast furnace slag-based materials is strongly influenced by the modulus of sodium silicate, preparation sequence, and calcination pretreatment. Thus, the best sodium silicate modulus (1.0) and optimized preparation sequence that involved using a cooled sodium hydroxide solution mixed with the red mud-blast furnace slag mixture before exposure to the sodium Csilicate were adopted. Then the calcination pretreatment of the red mud, gypsum, and lime was adopted to improve the compressive strength, and the optimal calcination temperature was selected to be 700 °C. The increase in the compressive strength (up to 71.82 MPa) resulted from a large number of active particles, which were generated by the fracture of numerous Si–O bonds and Al–O bonds after the calcination pretreatment. The results support the extensive utilization of red mud in building materials to prevent environmental pollution. [ABSTRACT FROM AUTHOR]

A specially designed cleaning system was adopted to wash away mud but keep coarse particles and stone powders in quarry waste. Then the cleaned quarry waste was used as concrete fine aggregate. Size distributions of all concrete constituents were analyzed, and workability and compressive strength of concrete were determined to evaluate gradation effect of cleaned quarry waste to improve size distributions of concrete constituents, thus improving concrete properties. Results showed that the designed cleaning system can wash away mud and keep stone powders and coarse particles in quarry waste. The particle sizes of stone powders were between 0.075 mm and 0.15 mm, and those of coarse particles were between 0.15 mm and 4.75 mm. When the cleaned quarry waste was used, continuous size distributions of all concrete constituents were formed, which solved discontinuous size distribution problems among cement, fine, and coarse aggregates. Therefore, concrete workability was improved and compressive strengths at different ages were increased. [ABSTRACT FROM AUTHOR]

The effects of type-F fly ash (FA) on the performance of Portland limestone cement (PLC) under sodium sulfate or magnesium sulfate attack at 5°C were evaluated. The degree of damage to the ternary blended cement exposed to 5 wt% sulfate solutions was assessed based on the evolution of the blended cement's appearance, compressive strength and volume. The sulfate product compositions from the blended cement under sulfate attack were analysed by Fourier transform infrared spectroscopy and quantitative X-ray powder diffraction. The results indicated that the PLC containing 40 wt% type-F FA was more resistant to sulfate attack than the control specimen without FA with similar mechanical properties, which was tested at a low temperature. The PLC containing 20 wt% type-F FA showed few effects in terms of improved resistance to sulfate attack. Analysis suggested that active aluminium in the FA glassy phase weakened the blended cement's resistance to sulfate attack because more ettringite was easily formed during the attack, which might accelerate thaumasite formation by means of the woodfordite route at low temperature. Therefore, the effects of type-F FA containing high contents of aluminium phase on the sulfate attack of PLC at low temperature need to be carefully evaluated and studied. [ABSTRACT FROM AUTHOR]

The influence of borax on the early hydration and rheological properties of dehydrated cement paste (DCP) composite reactivated cementitious materials (DCRCM) is investigated through analysis of the hydration kinetics and measurement of rheological parameters. Results show that the presence of borax can effectively restrain the early hydration rate of DCRCM, and this leads to reductions in both the hydration products and the flocculent structure in the paste. Obvious shear thinning occurs in the fresh DCRCM paste with the increase of shear rate, followed by gradually stabilised viscosity. As the amount of borax is increased, the yield stress and plastic viscosity of DCRCM paste decrease and the rheological properties are significantly improved. However, when the amount of borax is 4%, the rheological type of DCRCM paste changes to shear thickening at a high shear rate, which is unfavourable in terms of the improvement of rheological properties. [ABSTRACT FROM AUTHOR]

This study explored the strength limitations of municipal solid waste incineration (MSWI) bottom ash-based geopolymer, which can limit its use in building materials. The calcium content in MSWI bottom ash was increased by the addition of varying amounts of granulated blast furnace slag (GBFS) and calcium-containing chemicals. The results showed that the low calcium content of MSWI bottom ash in geopolymer was the main cause of insufficient polymerisation. Both GBFS and calcium-containing chemicals improved geopolymer microstructure and enhanced the degree of polymerisation, which clearly improved the compressive strength. However, further increases in geopolymer compressive strength were not significant when the GBFS content was greater than 40%, and the compressive strength decreased sharply when hydrated Ca(OH)2 content was greater than 5%. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose/poly(vinyl alcohol) (PVA) composite gels are prepared as separators for quasi-solid-state electrical double-layer capacitors (EDLCs) by a simple freeze-thawing method. Fourier-transform infrared spectroscopy, scanning electron microscopy and mechanical testing machine are used to characterize the structure and morphology. Compared with the PVA gel, the as-prepared composite gels show improved network structure and enhanced mechanical properties. The cyclic voltammetric curves, galvanostatic charge/discharge curves, electrochemical impedance spectroscopy and cycling performance of EDLCs with these composite gels are also evaluated. It is found that the EDLC with the optimum composite gel can work in a voltage window of 0-1.8 V and display a specific capacitance of 125.1 F g−1 (based on active carbon on one electrode) at a current density of 1 A g−1. Furthermore, it also has an excellent cycling stability with capacitance retention of ~ 88% after 1500 cycles. These results suggest that the composite gels can serve as a class of promising separators for EDLCs.Graphical abstract: [ABSTRACT FROM AUTHOR]

Supercapacitors have attracted much interest because of their high power density and long cycling life. However, the porous polypropylene membranes that are widely used as separators in supercapacitors are unfavorable for transporting ions and constructing the interfaces between electrolyte and electrodes due to their hydrophobic property. As a consequence, a crosslinked solid polymer electrolyte membrane and a semi‐interpenetrating polymer network (sIPN) were fabricated from sulfonated poly(ether ether ketone) (SPEEK) and poly(vinyl alcohol) (PVA), which can be used as hydrophilic separators. Their structures were examined using Fourier transform infrared spectroscopy. The electrochemical properties of assembled electrical double‐layer capacitors (EDLCs) were investigated using cyclic voltammetry, galvanostatic charging–discharging and impedance analysis. At a current density of 1 A g−1, a single electrode in the EDLC with the sIPN shows a specific capacitance of 134 F g−1. As a comparison, a single electrode in the EDLC with a SPEEK membrane demonstrates a specific capacitance of only 121 F g−1. After 1000 charge–discharge cycles, the specific capacitance retentions of both EDLCs are nearly 100%. These results suggest that the sIPN based on SPEEK and PVA has great potential to serve as a separator in EDLCs. © 2018 Society of Chemical Industry A semi‐interpenetrating polymer network based on sulfonated poly(ether ether ketone) (SPEEK) and poly(vinyl alcohol) (PVA) was used as an electrical double‐layer capacitor (EDLC) separator. The specific capacitance of the EDLC was increased by 10.7%. [ABSTRACT FROM AUTHOR]

A novel silica-based stationary phase with branched octadecyl groups was prepared by the sequential employment of the Michael addition reaction and photoinduced thiol-yne click chemistry with 3-aminopropyl-functionalized silica microspheres as the initial material. The resulting stationary phase denoted as SiO2-N(C18)4 was characterized by elemental analysis, FTIR spectroscopy and Raman spectroscopy, demonstrating the existence of branched octadecyl groups in silica microspheres. The separations of benzene homologous compounds, acid compounds and amine analogues were conducted, demonstrating mixed-mode separation mechanism on SiO2-N(C18)4. Baseline separation of basic drugs mixture was acquired with the mobile phase of acetonitrile/H2O (5%, v/v). SiO2-N(C18)4 was further applied to separate Corydalis yanhusuo Wang water extracts, and more baseline separation peaks were obtained for SiO2-N(C18)4 than those on Atlantis dC18 column. It can be expected that this new silica-based stationary phase will exhibit great potential in the analysis of basic compounds. [ABSTRACT FROM AUTHOR]

The Vasa gene is a vital germline marker to study the origin and development of germ cells and gonads in many organisms. Until now, little information was available about the characteristics of the Vasa gene in Schistosoma japonicum ( S. japonicum). In this study, we cloned the open reading frame (ORF) of the S. japonicum Vasa-like gene ( Sj-Vasa). The expression pattern and tissue localization of Sj-Vasa were also analyzed. Our results showed that Sj-Vasa shared the general feature of DEAD-box family member proteins. Sj-Vasa was transcribed and expressed throughout the S. japonicum life cycle with transcription exhibiting high levels at day 24 in both male and female worms, and the expression level in the female was always higher than that in the male. Sj-Vasa protein was localized in a variety of tissues of adult schistosomes, including the gonads (ovary, vitellarium, and testes), the subtegument, and some cells of the parenchyma. To our knowledge, this is the first report of preliminary characterization and expression of the Vasa-like gene that may play an important role in the development of the worm, especially in reproductive organs of S. japonicum. [ABSTRACT FROM AUTHOR]

Egress from host cells is a vital step of the intracellular life cycle of apicomplexan parasites such as Toxoplasma gondii. This phenomenon has attracted attentions from many research groups. Previous studies have shown that ethanol could stimulate the release of microneme proteins by elevating intracellular Ca concentration of T. gondii, resulting in the parasite egress from host cells. However, little information about egress is known on Eimeria species, the causative agent of coccidiosis in poultry and livestock. In this report, we studied the effect of ethanol and isopropanol on the egress of eimerian parasites. Eimeria tenella sporozoites cultured in primary chicken kidney cells were treated with ethanol and isopropanol, then the egressed parasites were analyzed. Ethanol and isopropanol could induce the rapid egress of E. tenella sporozoites from host cells. No substantial damage was found in parasite-egressed host cells. Compared to the freshly isolated sporozoites, the re-invading ability and reproductivity of the egressed parasites significantly decreased by 43.4 and 44.1 % individually. We also found that fewer sporozoites egressed from host cells when the parasites developed for a longer time before the alcohol treatment. These results demonstrate an in vitro egress mode different from that of T. gondii, facilitating the deciphering of the mechanisms of egress of eimerian parasites . [ABSTRACT FROM AUTHOR]

Selective enrichment of glycopeptides from complicated biological samples is critical for glycoproteomics to obtain the structure and glycosylation information of glycoproteins using mass spectrometry (MS), which still remains a great challenge. Hydrophilic interaction chromatography (HILIC)-based strategies have been proposed for selective isolation of glycopeptides via the interactions between the glycan of glycopeptides and the matrices. However, the application of these methods is limited by the medium selectivity of HILIC matrices. In this study, hydrophilic metal–organic frameworks (MOFs) were fabricated and used as a HILIC matrix. The cross-linked CD-MOFs (LCD-MOFs) were facilely prepared with γ-cyclodextrin as ligand and possessed nano-sized cubic structure, superior hydrophilicity, and bio-compatibility. The LCD-MOFs performance for the selective enrichment of glycopeptides from the complex biological samples were investigated with a digested mixture of human immunoglobulin G (IgG) that was used as standard samples. In the selectivity assessment, the non-glycopeptides causing ion suppression to the glycopeptides were effectively removed, the signal of glycopeptides were enhanced significantly by LCD-MOFs, and twenty glycopeptides were identified with 67 fmol of IgG digest. In addition, the resulting LCD-MOFs demonstrated the lower detection limit (3.3 fmol) with a satisfactory recovery yield (84–103%) for glycopeptide enrichment from a digest of IgG. Furthermore, a promising protocol was developed for the selective enrichment of glycopeptides from mouse liver, and 344 unique N-glycosylation sites that mapped to 290 different glycoproteins were identified in a single MS run. The results clearly demonstrated that when used in a HILIC matrix, LCD-MOFs have great potential for identifying and enriching low-abundant glycopeptides in complex biological samples. [ABSTRACT FROM AUTHOR]

Facile preparation of core-shell magnetic metal-organic framework nanospheres by a layer-by-layer approach is presented. The nanospheres have high surface area (285.89 cm2 g−1), large pore volume (0.18 cm3 g−1), two kinds of mesopores (2.50 and 4.72 nm), excellent magnetic responsivity (55.65 emu g−1), structural stability, and good dispersibility. The combination of porosity, hydrophobicity, and uniform magnetism was exploited for effective enrichment of peptides with simultaneous exclusion of high molecular weight proteins. The nanospheres were successfully applied in the selective enrichment of endogenous peptides in human serum. [ABSTRACT FROM AUTHOR]