BackgroundThe main cause of death in medulloblastoma is recurrence associated with leptomeningeal dissemination. During this process, the role of microRNAs (miRs) in the acquisition of metastatic phenotype remains poorly understood. This study aimed to identify the miR involved in leptomeningeal dissemination and to elucidate its biological functional mechanisms.Materials and methodsWe analyzed the miR expression profiles of 29 medulloblastomas according to the presence of cerebrospinal fluid (CSF) seeding. Differentially expressed miRs (DEmiRs) were validated in 29 medulloblastoma tissues and three medulloblastoma cell lines. The biological functions of the selected miRs were evaluated using in vitro and in vivo studies.ResultsA total of 12 DEmiRs were identified in medulloblastoma with seeding, including miR-192. The reduced expression of miR-192 was confirmed in the tumor seeding group and in the medulloblastoma cells. Overexpression of miR-192 inhibited cellular proliferation by binding DHFR. miR-192 decreased cellular anchoring via the repression of ITGAV, ITGB1, ITGB3, and CD47. Animals in the miR-192-treated group demonstrated a reduction of spinal seeding (P < 0.05) and a significant survival benefit (P < 0.05).ConclusionsMedulloblastoma with seeding showed specific DEmiRs compared with those without. miR-192 suppresses leptomeningeal dissemination of medulloblastoma by modulating cell proliferation and anchoring ability.
All-solid-state lithium batteries that use lithium metal as the anode have extremely high energy densities. However, for lithium metal anodes to be used, lithium dendrite formation must be addressed. Recently, the addition of lithium iodide (LiI) to sulfide solid electrolytes was found to suppress lithium dendrite formation. It is unclear whether the cause of this suppression is the improvement of the ionic conductivity of the solid electrolyte itself or the electrochemical properties of the lithium metal/solid electrolyte interface. In this study, the cause of the suppression was quantitatively elucidated. The effect of the interphase on the dendrite growth of doping LiI into Li3PS4 was determined using X-ray absorption spectroscopy and X-ray computed tomography measurements. The results revealed that LiI-doped Li3PS4 suppressed the dendrite formation by maintaining the interface due to inhibition of the reductive decomposition of Li3PS4. In addition, annealed LiI-doped Li3PS4 showed a greater dendrite suppression ability as the ionic conductivity increased. From these results, we not only found that the physical properties of the lithium metal/solid electrolyte interface and the bulk ionic conductivity contribute to lithium dendrite suppression but also quantitatively determined the proportions of the contributions of these two factors.
Recently, several sulfide solid electrolytes have been synthesized by liquid-phase synthesis for the commercialization of all-solid-state batteries. Unfortunately, the ionic conductivity for most of these electrolytes is unsatisfactory compared to that of solid electrolytes synthesized by conventional ball milling. This problem is attributed to different mechanisms between the liquid phase and the solid phase in reaction and formation. However, to the best of our knowledge, the effect of the solvent on the ionic conductivity of solid electrolytes has not been extensively investigated, although the identification of these properties is a key point in understanding the liquid-phase synthesis. Herein, the correlation between ionic conductivity and crystallinity originating from the solvents used has been investigated. As a result, the ionic conductivity of the electrolyte was found to be strongly dependent on polarity (δP) with low crystallinity. The highest ionic conductivity (5.09 × 10–4 S cm–1 at 25 °C) was obtained using butyl acetate, which exhibited the lowest δP. Moreover, the highest ionic conductivity of Li3PS4 produced by liquid-phase synthesis using butyl acetate was very comparable to that obtained by ball milling (5.14 × 10–4 S cm–1).
A regioselective, reagent-based method for the cyclization reaction of 2-amino-1,3,4-oxadiazole and 2-amino-1,3,4-thiadiazole core skeletons is described. The thiosemicarbazide intermediate 3 was reacted with EDC·HCl in DMSO or p-TsCl, triethylamine in N-methyl-2-pyrrolidone to give the corresponding 2-amino-1,3,4-oxadiazoles 4 and 2-amino-1,3,4-thiadiazoles 5 through regioselcective cyclization processes. The regioselectivity was affected by both R(1) and R(2) in p-TsCl mediated cyclization. It is shown in select sets of thiosemicarbazide 3 with R(1)(benzyl) and R(2)(phenyl). 2-Amino-1,3,4-oxadiazole 4 was also shown in the reaction of p-TsCl mediated cyclization. The resulting 2-amino-1,3,4-oxadiazole and 2-amino-1,3,4-thiadiazole core skeleton are functionalized with various electrophiles such as alkyl halide, acid halides, and sulfornyl chloride in high yields.
All-solid-state lithium batteries using inorganic sulfide solid electrolytes have good safety properties and high rate capabilities as expected for a next-generation battery. Presently, conventional preparation methods such as mechanical milling and/or solid-phase synthesis need a long time to provide a small amount of the product, and they have difficult in supplying a sufficient amount to meet the demand. Hence, liquid-phase synthesis methods have been developed for large-scale synthesis. However, the ionic conductivity of sulfide solid electrolytes prepared via liquid-phase synthesis is typically lower than that prepared via solid-phase synthesis. In this study, we have controlled three factors: (1) shaking time, (2) annealing temperature, and (3) annealing time. The factors influencing lithium ionic conductivity of Li 3 PS 4 prepared via liquid-phase synthesis were quantitatively evaluated using high-energy X-ray diffraction (XRD) measurement coupled with pair distribution function (PDF) analysis. It was revealed from PDF analysis that the amount of Li 2 S that cannot be detected by Raman spectroscopy or XRD decreased the ionic conductivity. Furthermore, it was revealed that the ionic conductivity of Li 3 PS 4 is dominated by other parameters, such as remaining solvent in the sample and high crystallinity of the sample.
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