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To describe the clinical features and prognosis of pediatric anti - N -methyl- d -aspartate receptor (NMDAR) encephalitis from a single center in northern China. The clinical and laboratory characteristics of hospitalized patients with anti -NMDAR encephalitis, stratified by age, were retrospectively studied. Risk factors including relapse and long-term (follow-up ≥1 year) outcomes were analyzed. A total of 273 patients were included between November 2011 and December 2019, and the average age of onset was 7.5 ± 4.0 years (0.5–15.8 years). Of them, 159（58.2%） were female, and the proportion of females increased with age. Seizures were the most common initial symptom. Movement disorders（86.1%） and psychiatric（82.4%） symptoms were most frequent in the acute phase. In the acute stage, the incidence of movement disorders decreased with age (χ2 = 10.676, p = 0.011), while the proportion of psychiatric symptoms increased with age (χ2 = 21.85, p < 0.001) The recurrence rate was 9.6% (24/250). Demyelination was an independent risk factor for relapse (p = 0.006, OR = 5.877, 95% CI: 1.658–20.835). Among the 210 patients who were followed up for more than one year, 28 patients had a poor prognosis (mRS ≥3). Onset age (p = 0.038，OR = 0.844, 95% CI: 0.720–0.991), precursor of viral encephalitis (p = 0.007，OR = 9.876, 95% CI: 1.878–51.940), and ICU admission (p = 0.023，OR = 5.924, 95% CI: 1.280–27.064) significantly affected the prognosis. The mortality rate was 2.9%. The characteristics of anti -NMDAR encephalitis in children are age-dependent. Early-onset, the precursor of viral encephalitis, and ICU admission may indicate poor prognosis. Demyelination may be a risk factor for recurrence. • Pediatric anti -NMDAR encephalitis has age-dependent characteristics. • Early onset, precursor of viral encephalitis, and ICU admission indicate poor prognosis. • Patintes with demyelination prone to relapse. [ABSTRACT FROM AUTHOR]

Transcranial direct current stimulation (tDCS) has been explored in epilepsy with limited samples, varied parameters, and inconclusive results. We aimed to study the efficacy of tDCS for patients with refractory focal epilepsy. We conducted a randomized, double-blind, sham-controlled, and three-arm (Group 1 (sham), Group 2 (20-min), and Group 3 (2 × 20-min)) tDCS parallel multicenter study. The primary outcome measurement was seizure frequencies (SFs). The study consisted of 28-days baseline, 14-days treatment, and 56-days follow-up. The cathode was placed over the epileptogenic focus, and the current intensity was 2 mA. The generalized estimating equations model, one-way analysis of variance, chi-square and Kruskal-Wallis test were used for analysis. Of the 82 enrolled patients, 70 patients were included for final analysis (Group 1, n = 21; Group 2, n = 24; and Group 3, n = 25). There was a significant reduction in SFs for both active tDCS groups compared with the sham group. Patients in Group 2 showed a significantly 50.73–21.91% greater reduction in SFs that lasted for 4 weeks (p = 0.008–0.060). Patients in Group 3 showed a significantly 63.19–49.79% greater reduction in SFs compared with the sham group that lasted for 5 weeks (p = 0.011–0.045). Patients in Group 3 had a 64.98–66.32% greater reduction in SFs at W9–W10, when compared with Group 2 (p = 0.021–0.022). Fourteen consecutive days tDCS significantly decreased SFs in patients with refractory focal epilepsy, with 2 × 20-min daily stimulation protocol being superior to 20-min daily stimulation protocol. • TDCS has been explored in epilepsy with limited samples, varied parameters and inconclusive results. • Safety and efficacy of two tDCS protocols were evaluated in patients with refractory focal epilepsy in a multicenter study. • TDCS treatment with 20-min and 2 × 20-min for consecutive 14 days significantly decreased SFs, compared to sham group. • The protocol using 2 × 20-min daily stimulation was superior to the protocol using 20-min daily stimulation only. [ABSTRACT FROM AUTHOR]

• A variable testing temperature was implemented in the dry-wet cycle test. • Effect of dry-wet ratio on mechanical properties and chloride corrosion resistance of concrete was investigated. • Higher dry-wet ratio exacerbates the deterioration of concrete performance. • Cumulative damage caused by variable temperature dry-wet cycle accelerates chloride erosion. Numerous factors influence the concrete performance in dry-wet cycle environment, with dry-wet ratio and temperature being particularly significant. In this paper, the effect of dry-wet ratios (1:3, 1:1, and 3:1) on the chloride corrosion resistance of concrete was studied, and the variable test temperature and constant test temperature were implemented in the dry-wet cycle. The deterioration law of chloride corrosion resistance of concrete was investigated, and the microstructure, phase composition, and pore structure were examined. The results showed that the deterioration degree of concrete performance was intensified by a higher dry-wet ratio. Compared with D1W3 (the dry-wet ratio is 1:3), the compressive strength, splitting tensile strength, flexural strength, mass, and relative dynamic elasticity modulus (RDEM) of D3W1 (the dry-wet ratio is 3:1) exposed to 72 dry-wet cycles decreased by 11.05%, 19.40%, 8.33%, 1.09%, and 6.14%, respectively, while the peak chloride content and erosion depth increased by 40.98% and 22.75%. Compared to the dry-wet cycle with constant temperature, the cumulative damage caused by the dry-wet cycle with variable temperature was greater, resulting in more severe deterioration of concrete performance. Variable temperature accelerated the diffusion rate and penetration depth of chloride ions. The peak chloride content and erosion depth of D1W3 were 27.08% and 18.44% higher than those of control group after 72 dry-wet cycles. Microscopic analysis confirmed that higher dry-wet ratio and variable temperature cycles accelerated the decay of mechanical strength and the decline of chloride erosion resistance. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the effect of a purified polysaccharide (PPPF) from pumpkin fruit on the Janus activated kinase (JAK)/signal transducer and activator of transcription (STAT) signaling during apoptotic process. The results showed that PPPF or STAT3 siRNA inhibits the cell growth of HepG2 cells via induction of apoptosis. Moreover, PPPF is able to suppress both constitutive and IL-6-induced phosphorylation of STAT3 (on Tyr705) and subsequent nuclear translocation in cancer cells. Such inhibition is found to be achieved through down-regulation of constitutive phosphorylation of JAK2, but not JAk1, c-Src, ERK1/2, and Akt, which means STAT3 tyrosine phosphorylation in HepG2 cells following PPPF treatment is associated with a reduction in JAK2 activity. In addition, the protein expression of SHP-1 was increased in cells in response to PPPF treatment, whereas SHP-2, SOCS-1 and SCOS-3 protein expression remain unchanged. In vivo animal experiment also indicated that PPPF had a potent inhibitory effect on tumor growth in mice bearing HepG2 xenograft tumors. Thus we can conclude that PPPF directly induces apoptotic cell death of HepG2 cells via down-regulation of the JAK2/STAT3 signal transduction pathways, which may facilitates the development of a therapeutic strategy for treating HCC. [ABSTRACT FROM AUTHOR]

Abstract: Graft copolymerization of rosin-(2-acryloyloxy)ethyl ester (RAEE) onto chitosan (Cts) was carried out under microwave irradiation using potassium persulfate as an initiator. The structures, morphology, and thermal properties of the Cts graft copolymer (Cts-g-PRAEE) were characterized by means of FT-IR, XRD, SEM, and TG. Also, Cts and Cts-g-PRAEE copolymer were used as carriers of fenoprofen calcium (FC), and their controlled release behavior in artificial intestinal juice were studied. The results show that the rate of release of fenoprofen calcium from the carrier of Cts-g-PRAEE copolymer becomes very slower than that of Cts in artificial intestinal juice. [Copyright &y& Elsevier]

Hydrothermal carbonization (HTC) of carbohydrates in general has been reported as a sustainable and green technique to produce novel carbon materials. Traditional HTC of carbohydrates leads to irregular carbonaceous particles with low porosity due to inevitable aggregation induced by the high surface energy and the failure of classical templates. The accrescent understanding of the reaction mechanism in the HTC "dark box" provides possibilities of engineering HTC carbonaceous materials in a refined way. In the past decades, some unprecedented carbonaceous structures were achieved via modified HTC processes. Those progresses reflect the mightiness of HTC for precise synthesis however the last specialized review on this topic is over a decade old. In this review, we summarize the advances in the precise engineering of carbonaceous materials with specific morphologies and structures by the bottom-up HTC of carbohydrates, especially monosaccharides and disaccharides. This review elucidates the HTC set screws for the shaping of and/or the pore-creation within the targeted nanostructured carbonaceous materials. The benefits for applications arised from the special control of HTC carbon are also discussed. This review could inspire further insight into the HTC process and broader application of carbon nanostructures made from renewable resources. [ABSTRACT FROM AUTHOR]

• The use of graphene and carbon fiber as conductive phase materials for the preparation of graphene-conductive asphalt-recycled permeable concrete. • Determined the optimal conductive filler ratio and achieved a resistivity of only 3.2 Ω·m. • The effect of the required snow melting thickness and snow melting time on the efficiency of pervious asphalt slabs for snow melting are studied. Conductive-asphalt-recycled pervious concrete alleviates the urban "heat island effect" and "rain island effect" to realize the resourceful and efficient use of waste concrete and also reduces the probability of urban snow and ice disasters to ensure the safety of winter operation of asphalt pavements in cold areas. This study presents a theoretical and technical basis for ensuring the winter operational safety of asphalt pavements in cold regions. First, we compound graphene and carbon fiber as conductive phase materials and prepare graphene-conductive asphalt-recycled permeable concrete using recycled coarse aggregates with straight top and bottom holes. Then, we analyzed the electrical conductivity, road performance, and electrothermal performance of the specimens prepared using different recycled coarse aggregate substitution rates under different snowfall levels to determine their snow melting efficiency and verify their application in cold regions. The results indicate that the quality of the recycled aggregates is high, the optimal conductive filler ratio is 0.3% polyacrylonitrile-based carbon fiber and 1.5% graphene by mass of asphalt, and the resistivity of the specimens is only 3.2 Ω·m. Moreover, the conductivity and road performance of the graphene-conductive asphalt-recycled concrete decreases with an increase in the replacement rate of the recycled coarse aggregate, and the artificially prefabricated upper and lower through holes affect the conductivity of the specimens to a certain extent. Further, the graphene-conductive asphalt-recycled pervious concrete shows excellent snow melting potential, and as the required snow melting thickness and snow melting time increase, the effect of pervious asphalt slabs for snow melting efficiency becomes more significant. Moreover, when the replacement rate of the recycled concrete aggregate is within the range of 0–50%, it can be completed in 2–3 h under different snowfall levels of snow melting requirements. [ABSTRACT FROM AUTHOR]

Anaerobic ammonium-oxidizing (anammox) bacteria convert ammonium and nitrite into N 2 in a chemolithoautotrophic way, meaning that they utilize CO 2 /HCO 3 solely as their carbon sources. Such autotrophic behavior limits their competitiveness with heterotrophic microorganisms in both natural environments and engineered systems. Recently, environmental metagenomic results have indicated the capability of anammox bacteria to metabolize short-chain fatty acids, further confirmed by limited experimental evidence based on highly enriched cultures. However, clear evidence is difficult to get because of the limits of traditional methodologies which rely on the availability of a pure anammox culture. In this study, we identified and quantified the uptake of acetate and propionate, on a single-cell level, by an anammox consortium that was dominated by Candidatus Jettenia asiatica (relative abundance of 96%). The consortium, growing in granular form with an average relative abundance of anammox bacteria of 96.0%, was firstly incubated in a13C-labelled acetate or propionate medium; then microtome sections were scanned by a nanometer-scale secondary ion mass spectrometer (NanoSIMS). The NanoSIMS scannings revealed that the consortium enriched acetate and propionate at a >10 times higher efficiency than bicarbonate incorporation. Our results also suggest that acetate or propionate was likely not assimilated by J. asiatica directly, but firstly oxidized to CO 2 , which then served as carbon sources for the follow-up autotrophy in J. asiatica cells. Furthermore, more [15N]ammonium was enriched by the propionate-fed consortium than the acetate-fed consortium despite that exactly the same amount of 13C atoms were supplied. Our study strongly indicates an alternative lifestyle, namely organotrophy, in addition to chemolithoautotrophy of anammox bacteria, making it more versatile than often expected. It suggests that the niche of anammox bacteria in both natural and engineered ecosystems can be much broader than usual assumed. Recognising this is important for their role in wastewater treatment and the global nitrogen turn-over rates. Image 1 • NanoSIMS reveals acetate- and propionate-engaged anammox processes. • The uptake of acetate and propionate by Jettenia asiatica was identified. • An alternative lifestyle to chemolithoautotrophy of anammox bacteria was proposed. [ABSTRACT FROM AUTHOR]

• It is feasible to recycle waste RAC in harsh environments by carbonation treatment. • Accelerated carbonation shows excellent repair effect on the damage of RRCA. • Producing C-RRCA per ton can capture 38.3 kg CO 2 with great environmental benefits. • RRAC with C-RRCA (content ≥ 6 %) shows good chloride ion permeability resistance. The recycling of waste recycled concrete (RC) has become a focus of many scholars. But the repeatedly recycling of RC used in harsh environments is still a difficult issue, due to the poorer quality of repeatedly recycled aggregate. This paper studied the repair effect of accelerated carbonation treatment on repeatedly recycled coarse aggregate (RRCA), which was collected from the failed parent recycled concrete via coupling action of high stress and freeze-thaw (F-T) cycles. Then the properties of carbonated repeatedly recycled aggregate concrete (C-RRAC) containing 0 %, 25 %, 50 %, 75 % and 100 % carbonated RRCA (C-RRCA) were evaluated. And the recycling potential of C-RRCA was explored, finally. The results suggested that accelerated carbonation treatment had excellent ability on repairing coupling damage of high stress and F-T in RRCA. Compared with RRCA, the apparent density of C-RRCA increased by 5.5 %, and water absorption, crushing value and soundness (mass loss) decreased by 26.6 %, 23.7 % and 19.9 %, respectively. The quality of C-RRCA was improved from type III to type II. With the growth of C-RRCA replacement rate, the water absorption, porosity, and chloride ion permeability coefficient of C-RRAC decreased by 34.4 %, 48 % and 55.6 %, respectively, and the compressive strength increased by 34.2 %. In addition, the C-RRAC could satisfied requirement of 100 years design service life of concrete structures in the E-type chloride environment, totally. According to the numerical fitting analysis, the minimum content of C-RRCA is 6 % under the condition that the compressive strength and chloride ion permeability of recycled aggregate concrete are met. It is feasible to recycle waste or even failed RC in high stress and F-T environment so as to reuse it in chloride environment, which provides a data support for effective utilization of waste RC under freeze-thaw environment. [ABSTRACT FROM AUTHOR]

In recent years, pig manure (PM) has been regarded as a valuable substrate for energy and resource recovery via bioprocesses such as anaerobic digestion (AD), however, the efficiency of digesting raw PM is limited by the presence of refractory compounds. In this study, we applied a series of pretreatment on raw PM, consisting of subsequent thermochemical pretreatment, enzymatic hydrolysis, tyndallization and filtration. The liquid PM hydrolysates were fed to an expanded granular sludge bed (EGSB) for the production of biogas. The general performance and population dynamics of the EGSB reactor were assessed during an extended operational period of 339 days. An efficient and stable digestion process was achieved under high organic loading rates (OLRs) up to 21 kg-COD/(m 3 ·d), agreeing with a sludge loading rate of 0.75 kg-COD/(kg-VSS·d), 1600 mg-NH 4 + -N/L and 17 mg/L of free ammonia nitrogen. The tyndallization decreased the total amount of active cells from 1 × 10 8 to 1 × 10 2 CFU/ml. Hence, bio-augmentation with pigs' intestinal microbiota was absent and the community dynamics were mainly credited to the composition of the substrate (i.e. PM hydrolysates) and the environmental conditions inside the reactor. The results showed the influence of both the seed community and the imposed loading rates on the evolutionary trajectory of the EGSB microbial community. Four bacterial genera ( Clostridium , Cytophaga , Bacillus and Bacteroides ) and two methanogenic genera ( Methanosaeta and Methanobacterium ) dominated the communities. An obvious shift from aceticlastic Methanosaeta to hydrogenotrophic Methanobacterium appeared when the OLR was increased to over 10 kg-COD/(m 3 ·d). [ABSTRACT FROM AUTHOR]

The existing researches on the recycled aggregate concrete (RAC) mainly focus on the recycling of waste concrete used in atmospheric environment, while the ones on the recycling of waste concrete subjected to complex environments are seldom reported. Reusing waste concrete in freeze-thaw (F-T) environment relates to the multi-generation recycling system of "high performance parent concrete-waste concrete-recycled aggregates (RAs)-next generation of recycled high-performance concrete (RHPC)-next generation of RAs". The efficient operation and sustainability of such recycling system depends on not only the performances of concrete, but also environmental load and economic benefits. The optimal balance between performance, environmental load and economic benefits for recycling waste concrete in F-T environment is generally affected by the performance of parent concrete and quality of RAs in the recycling system. Based on the theories of the emergy analysis and life cycle cost of structure, a sustainable design theory model of this innovative recycling system is proposed. In this model, high performance concrete (HPC) or RHPC is chosen as parent concrete and the performances of middle and low-quality RAs are improved by carbonation treatment method to gain high-quality RAs. The feasibility of the theoretical model is verified by the emergy analysis of the data of three-generation RAC, which provides a theoretical basis for the frost resistance quantitative design of multi-generation recycled concrete. [ABSTRACT FROM AUTHOR]

• The feasibility of recycling waste RAC in freeze–thaw environment is evaluated. • Freeze-thaw damage of RAC adversely affect the properties of second-generation CRA. • Freeze-thaw damage threshold of waste RAC as CRA for structural concrete is 0.36. • RAC with freeze–thaw failure cannot reuse as CRA for structure concrete. • Adhesive mortar and ITZ are the main carriers of freeze–thaw damage transfer. The reuse of waste recycled aggregate concrete (RAC) from freeze-thaw (FT) environment as coarse recycle aggregate (CRA) for structural concrete can effectively improve the application of second-generation CRA. This paper evaluated the reuse potential of waste RAC suffered different FT cycles as CRA for structural concrete by FT damage. C40 RAC specimens with 100% replacement rate were produced and the FT damage through a coupled action of FT cycles and 35% bending load was assessed. The RAC were crushed into second-generation CRA after every 100 FT cycles until FT failure. Results showed that the evolution process of FT damage on physical properties of CRA can be divided into four stages: reinforcement stage, transition stage, weakening stage and failure stage. In the evolution process, the apparent density of second-generation CRA decreased with FT cycles, while the crushing value, water absorption and soundness (mass loss) increased. The particle size of second-generation CRA gradually decreased with the accumulation of FT damage, and the screening curve of the CRA after 400 FT cycles cannot meet the requirements of continuous particle size. Relative dynamic modulus of elasticity (RDME) was more sensitive than mass loss rate in assessing the frost resistance durability of RAC. The FT damage threshold of RAC based on the properties requirements of type II and type III CRA was 0.085 and 0.359, respectively, indicating that the FT damage threshold of waste RAC crushing as CRA for structural concrete was 0.36, and the corresponding RDME was 64% rather than 60%. The microscopic analysis showed that the weakening of adhesive mortar and ITZ was the fundamental reason for the decrease of physical properties of the second-generation CRA. The CRA obtained from the RAC with FT failure cannot be reuse as aggregates for structure concrete. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we prepared an acidic polysaccharide (CPPA) from the roots of Codonopsis pilosula. The effects of CPPA on tumor cell growth, invasion, and migration were examined in vitro. The CPPA not only induced a potent inhibitory effect on the invasion and migration potential of human epithelial ovarian cancer HO-8910 cells in vitro, evaluated by wound healing, transwell and cell adhesion assays, but also had an efficient anti-proliferation effect on tumor cells. Moreover, the CD44 expression on the HO-8910 cells was also attenuated by CPPA treatment. Therefore, our results indicate that CPPA may be a potential candidate compound for the prevention of tumor metastasis, presumably by inhibiting invasion, migration and adhesion of tumor cells, as well as the CD44 expression on the tumor cells. [Copyright &y& Elsevier]

Abstract: Two acidic polysaccharide fractions (PTPa and PTPb) extracted from the roots of Polygala tenuifolia, were obtained by DEAE-Sephacel anion-exchange, and Sephadex G-100 gel-permeation chromatography. High-performance liquid chromatography (HPLC) identified that PTPa and PTPb was composed of Ara, Glc, Gal, Man and GlcUA in the proportion of 2.4:1.2:0.6:0.4:1.1 and 2.1:1.7:0.5:0.6:1.7, respectively. Their molecular weight was evaluated to be 5.9×104 (PTPa) and 2.5×104 Da (PTPb) as determined by high performance size exclusion chromatography (HPSEC). Pharmacological studies revealed PTPa and PTPb significantly inhibited the growth of A549 cells in vitro and exhibited significantly higher antitumor activity against solid tumor A549 in vivo than did a blank control. Moreover, treatment with two acidic polysaccharides caused an enhancement of superoxide dismutase (SOD) and catalase (CAT) activities in tumor-bearing mice and a reduction in thiobarbituric acid reactive substances (TBARS) level. Taken together, these results indicated that two acidic polysaccharides from the roots of P. tenuifolia may be useful as potent antitumor agents for the prevention of lung tumorigenesis. [Copyright &y& Elsevier]

Abstract: One polysaccharide PTP was isolated and purified from the roots of Polygala tenuifolia. It consisted of galactose, glucose and galactose in the ratio of 3.1:3.7:2.5, and a small amount of rhamnose, mannose and xylose. 17 general amino acids were identified to be components of the protein-bound polysaccharide analyzed by automatic amino acid analyzer. In order to test the anti-cancer activity of PTP, we investigated its effect against the growth of human ovarian cancer cells SKOV3 in vitro and in ovarian cancer rats. The intracellular reactive oxygen species (ROS) and glutathione (GSH) in SKOV3 cells following PTP treatment were also quantified to explore the possible mechanism underlying the antitumor activity of the polysaccharide. The result showed that PTP is effective on inhibiting the proliferation of SKOV3 cells in a concentration-dependent manner. Furthermore, treatment with PTP caused a rapid depletion of intracellular GSH content and accumulation of intracellular ROS, thus resulting in the apoptosis, which may prove to be a pivotal mechanism for its cancer protection action. In addition, a significant tumor growth inhibition effect was observed in nude mice after PTP administration for 7 weeks. All above indicated PTP could be beneficial towards ovarian cancer therapy. [Copyright &y& Elsevier]

Reducing the content of Cd in wheat grains is necessary for human health, especially in alkaline farmland in northern China where a large area of soils is heavily polluted with Cd. A field experiment was conducted to investigate the effects of wheat straw biochar (WB) and maize straw biochar (MB) combined solely with ferrous sulfate (FeSO 4) or combined with FeSO 4 and pig manure (PFWB and PFMB) on Cd bioavailability in soil and the phytotoxicity of Cd in wheat in an alkaline contaminated soil. The results showed that the application of these treatments decreased the concentrations of CaCl 2 -extractable Cd by 32.8–60.5% and increased the soil organic matter by 36.8–106.7% compared with those of the control treatment. The acid-soluble fraction of Cd was decreased by 3.7–16.8% but the residual fraction was increased by 1.7–13.7%. Furthermore, the addition of WB and MB increased the soil pH by 0.29 and 0.16 units, respectively, while the other treatments decreased the soil pH by 0.16–0.37 units. The concentrations of Cd in different wheat tissues were decreased in amended soils, and these decreases were positively correlated with CaCl 2 -extractable Cd and the acid-soluble fraction of Cd. The ability to accumulate Cd was in the order of root>straw>grain. In addition, there was a downward trend in the bio-concentration and translocation factors under different amendments. The amendments of PFWB and PFMB had better efficiency in the immobilization of Cd in soil and the inhibition of Cd uptake of wheat than WB and MB. In addition, the treatments of PFWB and PFMB increased the wheat yield by 14.3–16.2%, and thus have a great application prospect based on the cost-benefit analysis. Unlabelled Image • The physicochemical properties of biochars derived from wheat straw and maize straw were analyzed. • The application of biochars combined with ferrous sulfate and pig manure reduced the Cd bioavailability. • Acid-soluble Cd was transformed to residual speciation by different treatments. • Biochar combined with ferrous sulfate and pig manure had a better cost benefit. [ABSTRACT FROM AUTHOR]

• Utilization of RGFA as an alternative material for river sand is feasible. • RGA mortar showed comparable properties compared with NA mortar. • Unreacted metakaolin in RGFA was activated by alkali solution anew. • High bond strength of GP-RGFA ITZ lowered the decline tendency of CS. Geopolymer has been viewed as a potential, ideal and green material to replace cement. The recycling of Portland cement-based concrete as recycled aggregates was investigated diffusely, while the reuse of geopolymer was paid little attention. Exploring the feasibility and interfacial evolution of utilizing recycled geopolymer fine aggregate (RGFA) produced from waste geopolymer as the alternative for river sand (RS) was the core object in this research. Metakaolin to RS ratio of 1:2 and NaOH/Na 2 SiO 3 ratio of 0.5 by weight, and 12 M of NaOH solutions were adopted to prepare the referenced geopolymer mortar. Then five RGFA replacement rates (0%, 20%, 50%, 80% and 100%) were used to prepare the NA (RGFA) mortar. The tests of compressive strength, flexural strength and water absorption of mortars were performed. SEM was used to observe the interfacial transition zone (ITZ) between RGFA and new generated geopolymer paste. Results proved that RGFA mortar exhibited comparable mechanical properties compared with the RS mortar when replacement rate was less than 50%. Furthermore, more compact ITZs were obtained in RGFA mortar. The decreasing mechanical properties of RGFA mortar was primarily attributed to the weak properties of RGFA itself. The filler effects and compact ITZs relieved the decline tendency of mechanical property of RGFA mortar. It was convinced that utilizing RGFA to replace RS as fine aggregates in the construction activities was promising. [ABSTRACT FROM AUTHOR]

• An innovative ACP was prepared applied as tunnel fire resistant coating. • ACP has a lower thermal conductivity, excellent mechanical and durable properties. • ACP can defend effectively SCC from spalling in tunnel fire accidents. • 40 mm thickness of ACP can effectively withstand tunnel fire up to 2.5 h. Self-compacting concrete (SCC) widely used in tunnel structure is prone to spalling when it is subjected to the fire disaster. The fire-resistant materials coated on the surface of concrete are considered as an effective way to prevent concrete from being destroyed in a fire accident. However, current these coatings are difficult to withstand a high temperature, for example, tunnel fire temperature, and a longer-term fire. In this paper, a 40 mm thickness of SiO 2 aerogel cement paste (ACP) coating was prepared to investigate the protective effect for SCC in a simulated tunnel fire with the maximum temperature of 1100 °C for 2.5 h. The mechanical properties, thermal conductivity and fire resistance of SiO 2 ACP, and the compressive strength of SCC with or without ACP coating in the simulated tunnel fire were tested. The results showed that ACP exhibited excellent mechanical and durable performances and low thermal conductivity. The 40 mm thickness of ACP has a strong thermal insulation capacity and can effectively withstand tunnel fire up to 2.5 h. The SCC samples under the protection of ACP did not undergo compressive strength degradation and destruction of microstructure. The interfacial temperature of ACP and SCC was much lower than the critical value (380 °C) in a 2.5 h tunnel fire. Therefore, ACP can provide a good choice for protection of SCC in a tunnel fire with a high temperature and long time. [ABSTRACT FROM AUTHOR]