Since the infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported in China during December 2019, the coronavirus disease 2019 has spread on a global scale, causing the World Health Organization (WHO) to issue a warning. While novel vaccines and drugs that target SARS-CoV-2 are under development, this review provides information on therapeutics which are under clinical trials or are proposed to antagonize SARS-CoV-2. Based on the information gained from the responses to other RNA coronaviruses, including the strains that cause severe acute respiratory syndrome (SARS)-coronaviruses and Middle East respiratory syndrome (MERS), drug repurposing might be a viable strategy. Since several antiviral therapies can inhibit viral replication cycles or relieve symptoms, mechanisms unique to RNA viruses will be important for the clinical development of antivirals against SARS-CoV-2. Given that several currently marketed drugs may be efficient therapeutic agents for severe COVID-19 cases, they may be beneficial for future viral pandemics and other infections caused by RNA viruses when standard treatments are unavailable.

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In this study, we demonstrate the synthesis of the hetero-dialkaline hexafluorosilicate red phosphor KNaSiF 6 :Mn 4+ by etching Si wafers in a HF/KMnO 4 /NaMnO 4 • H 2 O mixed solution. The X-ray diffraction analysis indicates that the synthesized phosphor has an orthorhombic structure with the space group D 16 2h − Pnma. The luminescence properties of the phosphor are studied by photoluminescence (PL) analysis, PL excitation spectroscopy, and luminescence lifetime measurements, and are found to be intermediate of those of homo-dialkaline K 2 SiF 6 :Mn 4+ and Na 2 SiF 6 :Mn 4+ red phosphors.

Rh-MoOx /SiO2 (Mo/Rh=0.13) is an effective catalyst for the hydrogenolysis of 1,4-anhydroerythritol (1,4-AHERY) and provides 2-BuOH in high yield of 51 %. This is the first report of the production of 2-BuOH from 1,4-AHERY by hydrogenolysis. 1,4-AHERY was more suitable as a starting material than erythritol because the 2-BuOH yield from erythritol was low (34 %). Based on the kinetics and comparison of reactivities of the related compounds using Rh-MoOx /SiO2 and Rh/SiO2 catalysts, the modification of Rh/SiO2 with MoOx leads to the high activity and high selectivity to 2-BuOH because of the generation of reactive hydride species and the strong adsorption of 1,4-AHERY on MoOx species. The reaction proceeds by main two routes, (I) the combination of single C-O hydrogenolysis with the desorption of intermediates, a usual route in hydrogenolysis, and (II) multiple C-O hydrogenolysis without the desorption of intermediates from the active site, and the reaction mechanism for Route (II) is proposed.

This paper reports on a study of the photoluminescence excitation (PLE) spectra of Mn4+-activated K2SiF6 phosphor at 20 and 300 K. Measurements of the PLE spectra show that the sharp red emissions (2Eg →4A2g) at ∼630 nm are most efficiently excited by irradiation into the spin-allowed transitions 4A2g →4T2g (∼460 nm) and 4A2g →4T1g (∼360 nm). The first efficient excitation band 4A2g →4T2g is structureless at 300 K but shows a sharp origin and some oscillatory peaks at 20 K. A Fourier transform technique is used for analyzing such oscillatory peaks. The second excitation band 4A2g →4T1g shows a structureless shape even at a low temperature (20 K). The third excitation band with a peak at ∼250 nm is very weak and could be assigned as the 4A2g →4T1g transition. The direct excitation of the 2Eg state is also found to produce the sharp red emissions at ∼630 nm with a negligibly small offset in the configurational coordination. The Franck–Condon analysis makes it possible to accurately determine the zero-phonon line energies in the 3d3 electron transitions of the MnF6 2- octahedron.

These results suggest that sialylated MUC1 plays an important role in the progression of prostate cancer, and that its expression level in the primary lesion is a useful marker for the prognoses of patients undergoing endocrine therapy.

Mn4+- and Mn2+-activated red and yellowish-green phosphors have been synthesized by the wet chemical etching of Si wafers in aqueous HF/NaMnO4 · H2O and HF/Na2Cr2O7 · 2H2O/Mn solutions, respectively. X-ray diffraction patterns suggest that the synthesized powders are Na2SiF6:Mn4+ and Na2SiF6:Mn2+ with a trigonal structure (space group = D32-P321). Photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, and diffuse reflectance measurements were carried out to investigate the optical properties of the phosphors. Franck-Condon analyses of the PL and PLE spectra were performed to determine the zero-phonon energies of the Mn4+- and Mn2+-related transitions in Na2SiF6. Temperature-dependent PL and luminescence decay time measurements were performed from 20 to 300 K, and the obtained results are explained on the basis of the energy level diagram of the 3d3 (Mn4+) and 3d5(Mn2+) electrons in Na2SiF6, taking into account the thermal quenching effect. Electron spin resonance measurements were also performed. This is the first reported synthesis of a yellowish-green phosphor using Na2XF6 (X = a tetravalent metallic ion) as the host crystal.

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