Effects of hydroxyls on the structural and room temperature ferromagnetic properties of Co doped SnO2 nanoparticles

Co doped SnO₂ nanoparticles have been prepared via a wet chemical method with different precipitation processes. The structure and morphology of Co doped SnO₂ nanoparticles demonstrate that the nanoparticles are in a rutile single phase and uniform, respectively. X-ray photoelectron spectroscopy shows that the Co dopants are in 2+ oxidation valence state and doped ∼2 atm% in SnO₂ nanoparticles. Moreover, Raman spectroscopy further confirms that Co doped SnO₂ nanoparticles have single phase crystallinity without forming any extra modes related to secondary phases. The magnetic measurements reveal that all nanoparticles exhibit room temperature ferromagnetism (RTFM) due to the presence of disorders and defects introduced by hydroxyls in the crystal structure. In addition, it has been clearly observed that the saturated magnetic moments are strongly affected by the precipitation processes which control the incorporation of hydroxyls into the lattice.     

A case of fat necrosis after breast quadrantectomy in which preoperative diagnosis was enabled by MRI with fat suppression technique

A 63-year-old woman was found to have a left breast mass after quadrantectomy and radiation for bilateral breast cancer on postoperative cyclic examination. Intramammary recurrence could not be excluded by physical examination, mammography, or ultrasound examination. MR imaging with fat suppression technique revealed an oil-containing lesion, indicating fat necrosis. It was confirmed histologically that the mass-forming lesion included no cancer tissue. MR imaging with fat suppression technique appears to be a promising method for identification of postoperative mass lesions of the breast.     

Candibirin A,a furano­coumarin dimer isolated from Heracleum candicans Wall.

Candibirin A [systematic name: 9,9′‐(1,4‐dioxane‐2,5‐diyldi­methyl­ene­dioxy)­di(7H‐furo­[3,2‐g]­chromen‐7‐one)], a new furano­coumarin dimer, was isolated from Heracleum candicans Wall . ¹H NMR and MS spectra had indicated that the title compound was a dimer of heraclenin or heraclenol, but the linkage structure and its chirality were undetermined. The dioxane linkage, having the R,R configuration, has now been elucidated from di­methyl sulfoxide‐solvated crystals, C₃₂H₂₈O₁₀·2C₂H₆OS. Candibirin A is thus a dimerization product from heraclenin formed by reaction at the epoxy group. Di­methyl­form­amide‐solvated crystals, C₃₂H₂₈O₁₀·C₃H₇NO, adopt a different conformation, with a folded structure that differs from the extended structure in the dimethyl sulfoxide solvate. However, the puckering of the dioxane linker unit is very similar in the two conformers. This result shows that the rotation of the ether bonds, in the linker between the furano­coumarin and dioxane moieties, causes the conformational flexibility of (I).     

Turn-on fluorescence sensor for mono- and di-phosphonic acid derivatives using anthracene-based diamidine and its detection of amidinium-phosphonate and amidinium formation

The fluorescence detection of di-phosphonic acid and mono-phosphonic acid derivatives using the anthracene-based diamidine 1 has been investigated. The diamidine 1 forms 1:1 and 1:2 complexes with the di-phosphonic acid and mono-phosphonic acid derivatives, respectively, and showed a blue fluorescence (λ_em = 432–442 nm) in a DMSO solution. The formation of amidinium-phosphonate (complex formation) and dissociated amidinum (λ_em = 468 nm as a broad band) were distinguished by the difference in the fluorescence wavelength, and confirmed by DOSY NMR spectroscopy and TD-DFT calculations. The formation of a 1:2 complex with diamidine 1 and methylphosphonic acid having additional intermolecular hydrogen-bonding between the methylphosphonic acids is proposed.     

Toxic and Phototoxic Properties of the Protozoan Pigments Blepharismin and Oxyblepharismin*

Abstract— The toxic and phototoxic properties of blepharismin and oxyblepharismin that were purified from the pigments of a ciliated protozoan, Blepharisma japonicum, by thin-layer chromatography, were investigated in detail. The toxicity was tested against the ciliated protozoan Dileptus margaritifer, which is relatively sensitive to blepharismin. Although oxyblepharismin has been believed to be neither toxic nor phototoxic, it was found that oxyblepharismin is toxic in the dark and is also phototoxic. This shows that oxyblepharismin can act as a photosensitizer. The toxicity and phototoxicity of these pigments were compared with those of hypericin, which is known to be a typical, strong photosensitizer from plants. It was concluded that blepharismin and oxyblepharismin have strong intrinsic toxicities in the dark compared with hypericin, but their phototoxicities are slightly weaker than that of hypericin. This strong intrinsic toxicity supports our proposal that blepharismin acts as a defensive device against predators in the dark as well as in the light. The decrease in the defensive ability and the increase in the resistance to photokilling of Blepharisma concomitant with its color change from red to blue-purple in response to weak illumination can be explained by the decrease in toxicity and phototoxicity of the pigment itself and by the decrease in amount of the pigment.     

Development of dispersive XAFS system for analysis of time‐resolved spatial distribution of electrode reaction

Apparatus for a technique based on the dispersive optics of X‐ray absorption fine structure (XAFS) has been developed at beamline BL‐5 of the Synchrotron Radiation Center of Ritsumeikan University. The vertical axis of the cross section of the synchrotron light is used to disperse the X‐ray energy using a cylindrical polychromator and the horizontal axis is used for the spatially resolved analysis with a pixel array detector. The vertically dispersive XAFS (VDXAFS) instrument was designed to analyze the dynamic changeover of the inhomogeneous electrode reaction of secondary batteries. The line‐shaped X‐ray beam is transmitted through the electrode sample, and then the dispersed transmitted X‐rays are detected by a two‐dimensional detector. An array of XAFS spectra in the linear footprint of the transmitted X‐ray on the sample is obtained with the time resolution of the repetition frequency of the detector. Sequential measurements of the space‐resolved XAFS data are possible with the VDXAFS instrument. The time and spatial resolutions of the VDXAFS instrument depend on the flux density of the available X‐ray beam and the size of the light source, and they were estimated as 1 s and 100 µm, respectively. The electrode reaction of the LiFePO₄ lithium ion battery was analyzed during the constant current charging process and during the charging process after potential jumping.     

α-Dimethylaminomethylenation-induced Houben-Hoesch-type cyclization of cyanoacetanilides: a practical synthesis of 3-formyl-4-hydroxyquinolin-2(1H)-ones

The tandem reaction of cyanoacetanilides with triflic anhydride in DMF proceeded at room temperature to afford 3-formyl-4-hydroxyquinolin-2(1H)-ones in good to high yields. A detailed mechanistic study revealed that the tandem reaction proceeded via α-dimethylaminomethylenation, which promoted the subsequent Houben-Hoesch-type cyclization. Both α-functionalization and the cyclization steps were optimized, and a multi-gram scale synthesis of 3-formyl-4-hydroxyquinolin-2(1H)-one was achieved.