Solid-Liquid Separation after Liquid-Liquid Extraction. -Spectrophotometric Determination of Bismuth after Extraction of Its 2-mercaptobenzothiazole Complex with Molten Naphthalene-

A new reagent, 2-mercaptobenzothiazole,sodium salt is described for the spectrophotometric determination of bismuth(II) after extraction of bismuth complex with molten naphthalene. This reagent reacts with bismuth(II) to form a water-insoluble complex. The complex is insoluble in chloroform or benzene, but easily soluble in molten naphthalene. The extracted mixture of bismuth complex and naphthalene is dissolved in dimethylformamide and the trace amounts of bismuth are determined spectrophotometrically. The linearity between the absorbance and bismuth concentration is held for 10 - 200μg of bismuth in 10 ml of dimethylformamide. The molar absorptivity was calculated to be 1.1 x 10 4 l.mol-l･cm-l , the sensitivity 0.020 μg of bismuth per cm2 for the absorbance of 0.001 and the relative standard deviation 0.76 % for ten times determinations

A Novel Grafting of Polymers onto the Surface of Graphene Oxide

A simple grafting of polymers onto graphene oxide (GO) was achieved by polymer radical trapping, ligand-exchange reaction, and surface initiated cationic and anionic graft polymerization. Grafting of poly(ethylene glycol) (PEG) onto GO was successfully achieved by trapping of PEG radicals formed by thermal decomposition of PEG macroazo initiator to give PEG-grafted GO. The grafting of copolymers containing vinyl ferrocene moieties onto GO surfaces was also successfully achieved by the ligand-exchange reaction between ferrocene moieties of these copolymers and GO. Carboxyl groups on GO have an ability to initiate the cationic polymerizations of vinyl monomers, such as N-vinylcarbazole and isobutyl vinyl ether. The corresponding vinyl polymers were grafted onto GO, during the cationic polymerization, based on the termination of growing polymer cation by counter anion (carboxylate) groups on GO. It was found that the anionic ring-opening alternating copolymerization of epoxides with cyclic acid anhydrides was successfully initiated by potassium carboxylate groups on GO, introduced by neutralization of carboxyl groups with KOH, to give the corresponding polyester-grafted GO. The dispersibility of GO in organic solvents was remarkably improved by the grafting of the above polymers onto GO. In addition, easy preparation of reduced GO-based conducting polyaniline composite organogel will be discussed

X-Ray Reflection Nebulae with Large Equivalent Widths of Neutral Iron Ka Line in the Sgr C Region

This paper reports on the first results of the Suzaku observation in the Sgr C region. We detected four diffuse clumps with strong line emission at 6.4keV, Ka from neutral or low-ionized Fe. One of them, M359.38-0.00, is newly discovered with Suzaku. The X-ray spectra of the two bright clumps, M359.43-0.07 and M359.47-0.15, after subtracting the Galactic center diffuse X-ray emission (GCDX), exhibit strong Ka line from FeI with large equivalent widths (EWs) of 2.0-2.2keV and clear Kb of FeI. The GCDX in the Sgr C region is composed of the 6.4keV- and 6.7keV-associated components. These are phenomenologically decomposed by taking relations between EWs of the 6.4keV and 6.7keV lines. Then the former EWs against the associated continuum in the bright clump regions are estimated to be 2.4(+2.3_-0.7)keV. Since the two different approaches give similar large EWs of 2keV, we strongly suggest that the 6.4keV clumps in the Sgr C region are due to X-ray reflection/fluorescence (the X-ray reflection nebulae).Comment: Accepted for publication in PAS

Long-term maintenance of human induced pluripotent stem cells by automated cell culture system.

自動培養装置によるヒトiPS細胞の長期間培養に成功 . 京都大学プレスリリース. 2015-11-27.Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem (iPS) cells, are regarded as new sources for cell replacement therapy. These cells can unlimitedly expand under undifferentiated conditions and be differentiated into multiple cell types. Automated culture systems enable the large-scale production of cells. In addition to reducing the time and effort of researchers, an automated culture system improves the reproducibility of cell cultures. In the present study, we newly designed a fully automated cell culture system for human iPS maintenance. Using an automated culture system, hiPS cells maintained their undifferentiated state for 60 days. Automatically prepared hiPS cells had a potency of differentiation into three germ layer cells including dopaminergic neurons and pancreatic cells

Suzaku Spectroscopy of an X-Ray Reflection Nebula and a New Supernova Remnant Candidate in the Sgr B1 Region

We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (l, b) = (0.5, -0.1) near to the Galactic center (GC) with the Suzaku/XIS. Emission lines of S XV, Fe I, Fe XXV, and Fe XXVI were clearly detected in the spectrum. We found that the Fe XXV and Fe XXVI line emissions smoothly distribute over the Sgr B1 and B2 regions connecting from the GC. This result suggests that the GC hot plasma extends at least up to the Sgr B region with a constant temperature. There are two diffuse X-ray sources in the observed region. One of the two (G0.42-0.04) is newly discovered, and exhibits a strong S XV Ka emission line, suggesting a candidate for a supernova remnant located in the GC region. The other one (M0.51-0.10), having a prominent Fe I Ka emission line and a strongly absorbed continuum, is likely to be an X-ray reflection nebula. There is no near source bright enough to irradiate M0.51-0.10. However, the Fe I Ka emission can be explained if Sgr A* was ~ 10^6 times brighter 300 years ago, the light travel time for 100 pc to M0.51-0.10, than it is at present.Comment: 10 pages, 10 figure

Polymer with Zwitterionic Structure in Main Chain via Polyaddition of Bifunctional Cyclic Amidine and Diisothiocyanate

A polymer containing a zwitterionic form in the main chain was synthesized by the polyaddition of a bifunctional cyclic amidine with diisothiocyanate. The ion conductivity of a composite film consisting of the polymer and lithium chloride was evaluated by AC impedance measurements, demonstrating its potential applicability as an ion‐conductive material