Cobalt‐Catalyzed Transformation of Molecular Dinitrogen into Silylamine under Ambient Reaction Conditions

The first successful example of cobalt‐catalyzed reduction of N₂ with Me₃SiCl and Na as a reductant, under ambient reaction conditions, gives N(SiMe₃)₃, which can be readily converted into NH₃. In this reaction system, 2,2′‐bipyridine (bpy) is found to work as an effective additive to improve substantially the catalytic activity. Co?N₂ complexes bearing three Me₃Si groups as ancillary ligands are considered to work as key reactive species based on DFT calculations. The DFT results also allow the proposal of a detailed reaction pathway for the transformation of N₂ into N(SiMe₃)₃.     

Thermochromic properties of low-melting ionic uranyl isothiocyanate complexes

Temperature-dependent yellow-to-red colour changes of uranyl thiocyanate complexes with 1-alkyl-3-methylimidazolium cations have been studied by different spectroscopic methods and this phenomenon is attributed to changes in the local environment of the uranyl ion, including the coordination number, as well as to cation-anion interactions.     

Open-access and multi-directional electroosmotic flow chip for positioning heterotypic cells

We propose a novel method of cell positioning using electroosmotic flow (EOF) to analyze cell-cell interactions. The EOF chip has an open-to-air configuration, is equipped with four electrodes to induce multi-directional EOF, and allows access of tools for liquid handling and of physical probes for cell measurements. Evaluation of the flow within this chip indicated that it controlled hydrodynamic transport of cells, in terms of both speed and direction. We also evaluated cell viability after EOF application and determined appropriate conditions for cell positioning. Two cells were successively positioned in pocket-like microstructures, one in each micropocket, by controlling the EOF direction. As an experimental demonstration, we observed contact interactions between two individual cells through gap junction channels. The EOF chip should provide ways to elucidate various cell-cell interactions between heterotypic cells.     

Study of effective factors in detection of irradiated food using thermoluminescence based on the models of reference minerals

In the thermoluminescence (TL) detection method for irradiated foods, accurate standards have been developed for detecting irradiated foods. The standard method describes that emission maximum temperature (T1i) and TL ratio for non-heated or non-mixed sample can be in the range of 150–250 °C and more than 0.1, respectively, when it was irradiated food. But when irradiated food is heated up to 200 °C, or mixed up with non-irradiated stuffs, T1i and TL ratio would not drop in the range. Here we examined the effects of the two processes, heating and mixing with non-irradiated food, on T1i and G1/G1k ratio (ratio of G1 and average G1 for 1-kGy-irradiated JF2, this value is modeled after TL ratio) using a model consisting of irradiated and non-irradiated geochemical standards of feldspar (JF1, JF2, PF, etc.). T1i temperatures for irradiated JF1, JF2, and PF ranged from 163 to 175 °C, while those for the non-irradiated JF2 ranged from 253 to 263 °C. T1i temperatures for 5-kGy-irradiated and preheated JF2 for 10 s, 20 s, and 30 s at 180 °C were 215, 225, and 231 °C, respectively.When JF2 was irradiated from 100 Gy to 5 kGy, the T1i was almost constant at any doses. G1/G1k ratios at 100, 200, and 500 Gy were 0.15, 0.23, and 0.60, respectively. G1/G1k ratio was proportional to the given dose at the integration temperature ranges.The TS sample, which originated from farm soil in Tanegashima Island, gave the same results as JF2. T1is for 5-kGy-irradiated and preheated JF2 for 20 s at 150, 180, and 200 °C were 197, 225, and 246 °C, respectively. Longer and higher preheating resulted in higher T1i. Longer and higher preheating extremely reduced the G1/G1k ratio, and in some cases the ratio was less than 0.1. This means TL ratio is useless in determination of the standard for irradiated food.Peak temperatures for JF2 in mixture of 5-kGy-irradiated to non-irradiated (1.25–5%) were 261–263 °C (non-irradiated portion, T1n) and 177–180 °C (irradiated portion T1i). The peak positions are almost the same as those of original components and would not be affected by the mixing ratio. But TL ratio could not be used to determine irradiated food because mixing would reduce it remarkably.Some of the glow curves were simulated by a computer program.In conclusion, T1i/n is a key factor in an irradiated food determination practice for sample containing feldspar, rather than TL ratio.     

Quasiparticle scattering induced by charge doping of iron-pnictide superconductors probed by collective vortex pinning

Charge doping of iron-pnictide superconductors leads to collective pinning of flux vortices, whereas isovalent doping does not. Moreover, flux pinning in the charge-doped compounds is consistently described by the mean-free path fluctuations introduced by the dopant atoms, allowing for the extraction of the elastic quasiparticle scattering rate. The absence of scattering by dopant atoms in isovalently doped BaFe2(As(1-x)P(x))(2) is consistent with the observation of a linear temperature dependence of the low-temperature penetration depth in this material.     

Synthesis of Well‐Defined Telechelic Aromatic Polyamides by Chain‐Growth Polycondensation: Application to the Synthesis of Block Copolymers of Polyamide and Poly(tetrahydrofuran)

Well‐defined telechelic‐type aromatic polyamides having a secondary amino group and a phenyl ester moiety at each chain end were prepared by the chain‐growth polycondensation of phenyl 4‐(octylamino)benzoate ( 1 ) with initiator 2 (N‐tert‐butoxycarbonylated 1 ), followed by deprotection of the N‐protecting group of the initiator unit. This polycondensation was applied to the synthesis of well‐defined di‐ and triblock copolymers of aromatic polyamides and poly(tetrahydrofuran) (poly(THF)) by the reaction of the terminal secondary amino group of the polyamide with the living cationic propagating group of poly(THF).

Block copolymers of polyamide and poly(tetrahydrofuran).     

Recording characteristics of high-density thin optical disk using near-field optical recording

We report on the recording characteristics of a near-field optical recording thin optical disk (NFR-TOD). We proposed a new cooling-less-type write strategy for recording, applied it to the NFR-TOD experimental system, and also applied a partial response maximum likelihood (PRML) signal processing, which was evaluated and optimized the PR coefficient for playback signals of the prototype NFR-TOD. The NFR-TOD has a track pitch of 160 nm and improved recording characteristics. The experimental results of the prototype NFR-TOD and the system indicate sufficiently low bit error rates (bERs) for recorded data at a fourfold higher recording density than the current Blu-ray disk.     

Halogenated cladosporols produced by the sodium halide-supplemented fermentation of the plant-associated fungus Cladosporium sp. TMPU1621

A new cladosporol derivative, 2-chloro-cladosporol D (6), was isolated together with known cladosporol (1), cladosporols B–D (2–4), and cladosporol F (5) from the culture broth of plant-associated Cladosporium sp. TMPU1621. The structure of 6 was elucidated from spectroscopic analyses including NMR and MS data. The productivity of 6 increased in 3% NaCl-supplemented medium; therefore, fermentation of the producing fungus TMPU1621 with 3% NaBr was investigated, leading to the induced production of a new halogenated cladosporol, 2-bromo-cladosporol D (7). Compound 2 showed the lowest MIC values of 3.13 and 12.5?μg/mL against two MRSA strains, ATCC43300 and ATCC700698, respectively.