RESUMEN
Water that penetrates through cracks in concrete can corrode steel bars. There is a need for reliable and practical seepage sensing technology to prevent failure and determine the necessary maintenance for a concrete structure. Therefore, we propose a modified plasma-assisted electrochemical exfoliated graphite (MPGE) nanosheet smart tag. We conducted a comparative study of standard and modified RFID smart tags with sensor technology for seepage detection in concrete. The performance of both smart tags was tested and verified for seepage sensing in concrete, characterized by sensor code and frequency values. Seepage was simulated by cracking the concrete samples, immersing them for a designated time, and repeating the immersing phase with increasing durations. The test showed that the modified smart tag with 3% MPGE and an additional crosslinking agent provided the best sensitivity compared with the other nanosheet compositions. The presence of 3D segregated structures on the smart tag's sensing area successfully enhanced the sensitivity performance of seepage detection in concrete structures and is expected to benefit structural health monitoring as a novel non-destructive test method.
RESUMEN
A solid-state reaction method was used to synthesize Ca2+x MgSi2Eu0.025O7+x (x = 0-1.0) powders in the air atmosphere and in a reduction atmosphere (95% N2 + 5% H2) at 1350 °C and 4 h, and the reduction atmosphere was removed at 800 °C. Only the Ca2MgSi2O7 phase was found in the XRD pattern of the synthesized Ca2MgSi2Eu0.025O7 powder. The first important discovery was that when the x value of Ca2+x MgSi2Eu0.025O7+x powders was increased from 0.2 to 0.8, both Ca2MgSi2O7 and Ca3MgSi2O8 phases coexisted in the synthesized Ca2+x MgSi2Eu0.025O7+x powders, and the diffraction intensity of the Ca2MgSi2O7 (Ca3MgSi2O8) phase decreased (increased) with the x value. The second important discovery was that the Ca2MgSi2Eu0.025O7 phosphor exhibited stronger photoluminescence excitation (PLE), photoluminescence (PL), and decay curve properties than the Ca2.2MgSi2Eu0.025O7.2 phosphor, and the Ca3MgSi2Eu0.025O8 phosphor exhibited stronger PLE, PL, and decay curve properties than the Ca2+x MgSi2Eu0.025O7+x phosphors for x = 0.4, 0.6, and 0.8. For x = 0.2-0.8, the PL spectra of the Ca2+x MgSi2Eu0.025O7+x phosphors were a combination of the PL spectra of Ca2MgSi2Eu0.025O7 and Ca3MgSi2Eu0.025O8 phosphors. The third important discovery was that as the x value was increased, the maximum emission peak wavelengths of the Ca2+x MgSi2Eu0.025O7+x phosphors shifted to a lower value, the maximum emission intensity of the PL spectra increased, and the emission light changed from green and cyan to blue.
RESUMEN
BACKGROUND: Polysaccharides are important active ingredients in Ophiocordyceps gracilis with many physiological functions. It can be obtained from the submerged fermentation by the anamorph (Paraisaria dubia) of Ophiocordyceps gracilis. However, it was found that the mycelial pellets of Paraisaria dubia were dense and increased in volume in the process of fermentation, and the center of the pellets was autolysis due to the lack of nutrient delivery, which extremely reduced the yield of polysaccharides. Therefore, it is necessary to excavate a fermentation strategy based on morphological regulation for Paraisaria dubia to promote polysaccharides accumulation. RESULTS: In this study, we developed a method for enhancing polysaccharides production by Paraisaria dubia using microparticle enhanced technology, talc microparticle as morphological inducer, and investigated the enhancement mechanisms by transcriptomics. The optimal size and dose of talc were found to be 2000 mesh and 15 g/L, which resulted in a high polysaccharides yield. It was found that the efficient synthesis of polysaccharides requires an appropriate mycelial morphology through morphological analysis of mycelial pellets. And, the polysaccharides synthesis was found to mainly rely on the ABC transporter-dependent pathway revealed by transcriptomics. This method was also showed excellent robustness in 5-L bioreactor, the maximum yields of intracellular polysaccharide and exopolysaccharides were 83.23 ± 1.4 and 518.50 ± 4.1 mg/L, respectively. And, the fermented polysaccharides were stable and showed excellent biological activity. CONCLUSIONS: This study provides a feasible strategy for the efficient preparation of cordyceps polysaccharides via submerged fermentation with talc microparticles, which may also be applicable to similar macrofungi.
Asunto(s)
Polisacáridos Fúngicos/biosíntesis , Hypocreales/metabolismo , Reactores Biológicos , Vías Biosintéticas , Medios de Cultivo , Fermentación , Perfilación de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Hypocreales/citología , Hypocreales/genética , Micelio/citología , Tamaño de la Partícula , TalcoRESUMEN
In this study, Eu-doped Li2 (Ba1-x Srx )SiO4 powders (x = 0, 0.2, 0.4, and 0.6) were synthesized at 850°C in a reduction atmosphere (5% H2 + 95% N2 ) for a duration of 1 h using a solid-state reaction method. The reduction atmosphere was infused as the synthesis temperature reached 850°C, and was removed as the temperature dropped to 800-500°C. Li2 (Ba1-x Srx )SiO4 (or Li2 BaSiO4 ), (Ba,Sr)2 SiO4 (or BaSiO4 ), and Li4 SiO4 phases co-existed in the synthesized Eu-doped Li2 (Ba1-x Srx )SiO4 powders. A new finding was that the reduction atmosphere removing (RAR) temperature of the Li2 (Ba1-x Srx )SiO4 phosphors had a large effect on their photoluminescence excitation (PLE) and PL properties. Except for the 800°C-RAR-treated Li2 BaSiO4 phosphor, PLE spectra of all other Li2 (Ba1-x Srx )SiO4 phosphors had one broad emission band with two emission peaks centred at ~242 and ~283 nm; these PL spectra had one broad emission band with one emission peak centred at 502-514 nm. We showed that the 800°C-RAR-treated Li2 BaSiO4 phosphor emitted a red light and all other Li2 (Ba1-x Srx )SiO4 phosphors emitted a green light. Reasons for these results are discussed thoroughly.
