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. Graphical Abstract
A solid-state reaction method was used to synthesize Ca 2+x MgSi 2 Eu 0.025 O 7+x (x = 0−1.0) powders in the air atmosphere and in a reduction atmosphere (95% N 2 + 5% H 2 ) at 1350 °C and 4 h, and the reduction atmosphere was removed at 800 °C. Only the Ca 2 MgSi 2 O 7 phase was found in the XRD pattern of the synthesized Ca 2 MgSi 2 Eu 0.025 O 7 powder. The first important discovery was that when the x value of Ca 2+x MgSi 2 Eu 0.025 O 7+x powders was increased from 0.2 to 0.8, both Ca 2 MgSi 2 O 7 and Ca 3 MgSi 2 O 8 phases coexisted in the synthesized Ca 2+x MgSi 2 Eu 0.025 O 7+x powders, and the diffraction intensity of the Ca 2 MgSi 2 O 7 (Ca 3 MgSi 2 O 8 ) phase decreased (increased) with the x value. The second important discovery was that the Ca 2 MgSi 2 Eu 0.025 O 7 phosphor exhibited stronger photoluminescence excitation (PLE), photoluminescence (PL), and decay curve properties than the Ca 2.2 MgSi 2 Eu 0.025 O 7.2 phosphor, and the Ca 3 MgSi 2 Eu 0.025 O 8 phosphor exhibited stronger PLE, PL, and decay curve properties than the Ca 2+x MgSi 2 Eu 0.025 O 7+x phosphors for x = 0.4, 0.6, and 0.8. For x = 0.2−0.8, the PL spectra of the Ca 2+x MgSi 2 Eu 0.025 O 7+x phosphors were a combination of the PL spectra of Ca 2 MgSi 2 Eu 0.025 O 7 and Ca 3 MgSi 2 Eu 0.025 O 8 phosphors. The third important discovery was that as the x value was increased, the maximum emission peak wavelengths of the Ca 2+x MgSi 2 Eu 0.025 O 7+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.
First, a solid-state reaction method was used to synthesize a [Formula: see text] phosphor at 1250[Formula: see text]C–1400[Formula: see text]C for 1 h, and its crystal structures and photoluminescence properties were investigated as a function of synthesis temperature. When the furnace reached the synthesis temperature, the 5% [Formula: see text] reduction atmosphere was infused and the reduction atmosphere was removed as the temperature was dropped to 800[Formula: see text]C. When 1200[Formula: see text]C was used as the synthesis temperature, the [Formula: see text], [Formula: see text], and [Formula: see text] phases co-existed; only one weak emission peak was observed in the photoluminescence excitation (PLE) spectra, and two weak emission peaks were observed in the photoluminescence emission (PL) spectra. When the [Formula: see text] phosphors were synthesized at a temperature higher than 1200[Formula: see text]C, the diffraction intensities of [Formula: see text], [Formula: see text], and [Formula: see text] phases were almost unchanged, but the crystal sizes of [Formula: see text] powders increased. For [Formula: see text] phosphors, PLE spectra had one broad exciting band with two centered wavelengths of 317 and 365 nm, and PL spectra had one emission band with one centered wavelength of 513 nm. As the synthesis temperature rose, the emission intensities of PLE and PL spectra increased. Second, we show that the removed temperature of reduction atmosphere of [Formula: see text] phosphors had an apparent effect on their emission properties of PLE and PL spectra.
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.
We had successfully synthesized green-emitting phosphors based on Li2BaSiO4 material activated by bivalent europium ions (Eu[Formula: see text]) using a solid-state reaction method in a reducing gas environment and investigated their luminescence properties. The Li2BaSiO4:0.003Eu[Formula: see text] (LSB-Eu) phosphors were synthesized at 850[Formula: see text]C for 1 h, and the reduction gas was removed at 500[Formula: see text]C, 600[Formula: see text]C, 700[Formula: see text]C and 800[Formula: see text]C, respectively. XRD pattern showed that the Li2BaSiO4, Ba2SiO4 and Li4SiO4 phases were observed in the synthesized Li2BaSiO4 composition. As the reduction gas was removed at 800[Formula: see text]C, the LSB-Eu phosphor emitted a weak red light rather than a green light. Two weak emission peaks were found at about 588 nm and 613 nm corresponding to [Formula: see text] and [Formula: see text] transitions. As temperature to remove the reduction gas was lower than 800[Formula: see text]C, the emission spectra of LSB-Eu phosphors reveled a broad peak centered at 501 nm, which emitted a green color. The intensity of photoluminescence excitation (PLE) photoluminescence emission (PL) spectra increased as the removing temperature was decreased from 700[Formula: see text]C to 500[Formula: see text]C and saturated at 500[Formula: see text]C. These results show that LSB-Eu can be a noteworthy candidate of green-emitting phosphor for the investigation of white light-emitting diodes (WLEDs).
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