Simultaneous determination of a novel oral Janus kinase inhibitor ASP015K and its sulfated metabolite in rat plasma using LC‐MS/MS

A sensitive and selective liquid chromatography with tandem mass spectrometry (LC‐MS/MS) was developed for determining the concentrations of novel Janus kinase inhibitor ASP015K and its sulfated metabolite M2 in rat plasma. This method involves solid‐phase extraction (SPE) from 25 μL of rat plasma. LC separation was performed on an Inertsil PH‐3 column (100 mm L ×4.6 mm I.D., 5 µm) with a mobile phase consisting of 10 mM ammonium acetate and methanol under linear gradient conditions. Analytes were introduced to the LC‐MS/MS through an electrospray ionization source and detected in positive‐ion mode using selected reaction monitoring. Standard curves were linear from 0.25 to 500 ng/mL (r ≥0.9964). This assay enabled quantification of ASP015K and M2 at a concentration as low as 0.25 ng/mL in rat plasma. Validation data demonstrated that the method is selective, sensitive and accurate. Further, we also successfully applied this method to a preclinical pharmacokinetic study in rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Magnetic phase transition in ɛ-In x Fe2 − x O3 nanowires

This paper reports on a study of magnetic properties of ordered arrays of ?-In _x Fe_{2 ? x} O₃ (x = 0.24) nanowires possessing a high room-temperature coercive force of 6 kOe. Lowering the temperature below 190 K brings about a sharp decrease of the coercive force and magnetization of nanowires driven by the magnetic phase transition from the ferrimagnetic into antiferromagnetic phase. The transition is accompanied by a decrease of the magnetic anisotropy constant, which accounts for the anomalous frequency dependence of the position of the maximum in the temperature dependence of dynamic magnetic susceptibility. In the low-temperature phase, a spin-flop transition in the magnetic field of 28 kOe has been observed at T = 2 K. Lines related to the high-temperature hard-magnetic and low-temperature phases have been identified in electron spin resonance spectra of the nanowires. A line lying near zero magnetic field and evolving from the nonresonant signal related to the microwave magnetoresistance of the sample has also been detected.     

57Fe Mössbauer Spectroscopic Study of Fe–B Compounds

Hyperfine Interactions - 57Fe Mössbauer measurements of Fe doped β-rhombohedral boron (β-B) were performed in the temperature range between 300 K and 4.5 K. The spectra of Fe doped...     

Collisional ionization of highly excited neon atoms by nonpolar hydrocarbons

When benzene, acetylene and ethylene were allowed to collide with Ne Rydberg atoms (17?n?40), significant Ne⁺ ions were observed. Their cross sections were estimated, with reference to the ionization by H₂O, to be as large as 10^?14–10^?15 cm². However, no Ne⁺ signals were observed when ethane, methane and N₂ were used as targets. Theoretical estimates of the cross sections for ionization by interaction of the quadrupole moment and polarizability of the first three molecules are several orders of magnitude smaller than the experimental cross sections given above. A similarity of this phenomenon to the scattering of a thermal electron by benzene etc., observed by Christophorou et al., is suggested.     

Dynamic solvation effects on surface-impact dissociation of I 2 - (CO2)n

Surface-impact dissociation of I ₂ ^- (CO₂)n was studied by a molecular dynamics simulation in comparison with the experimental results. The branching fraction, ? _dis, of the I ₂ ^- dissociation was calculated as a function of the parent cluster size, n. This computational result reproduces the experimental one. We calculated a number of the I ₂ ^- dissociation events starting from given initial orientations. The most favorable molecular orientation obtained supports the wedge effect in which a CO₂ molecule located at the waist position of the I ₂ ^- core ion splits the I ₂ ^- bond as if a piece of wood is split by a mechanical thrust against a wedge. The time profile of the wedge action calculated for the I ₂ ^- (CO₂) impact shows that more than 20 % of the collision energy is converted to the vibrational energy of the I ₂ ^- .     

Chemical speciation of chromium in sea water: Part 3. The determination of chromium species

A method for the determination of chromium(III), chromium(VI) and organicallybound chromium in sea water is reported. It is confirmed that sea water contains about 9 × 10^-9 M dissolved chromium. This is shown to be divided as ca. 15% inorganic Cr(III), ca. 25% inorganic Cr(VI) and ca. 60% organically-bound chromium. It is suggested that the inconsistency of earlier results on the dominant chromium species and its concentration in sea water is largely due to the fact that organically bound chromium species were not considered.     

Nonlinear magnetooptical effects caused by piezoelectric ferromagnetism in F3m-type Prussian blue analogues

The second harmonic generation (SHG) and magnetization-induced SHG (MSHG) of AMA[MB(CN)6]-type (F3m) Prussian blue analogues (i.e., CsCo[Cr(CN)6].0.5H2O and RbMn[Fe(CN)6]) were observed. A large interaction between the nonlinear optical response and magnetic spins was observed in CsCo[Cr(CN)6].0.5H2O. These observations of SHG and MSHG imply that AMA[MB(CN)6]-type Prussian blue analogues are piezoelectric above the Curie temperature (TC) and piezoelectric ferromagnet below TC.     

Effect of carbon addition on synthesis of BN nanolayers encapsulating Fe fine particles and BN nanotubes

Boron nitride (BN) nanolayers encapsulating iron (Fe) fine particles and BN nanotubes were synthesized by annealing mixture powders of hematite, boron and carbon (C) at 1473 K for 2 h in a nitrogen atmosphere. The particles exhibited good soft magnetic properties. The thickness of BN nanolayers increased in the range of 10-100 nm with increasing C content in the mixture powders, which results in providing improvement of oxidation resistance of the particles. In the BN layers, no C was detected. BN nanotubes with diameters of ∼100 nm were also synthesized, and they had cup-stacked and bamboo-like structures.     

Direct observation of charge transfer in double-perovskite-like RbMn[Fe(CN)6

The charge density distribution has been determined for a transition metal cyanide, RbMn[Fe(CN)(6)], by means of the maximum entropy-Rietveld method combined with the highly angularly resolved synchrotron radiation x-ray powder diffraction at SPring-8 BL02B2. We directly observed a charge transfer from the Mn site to the Fe site in the low-temperature phase. On the basis of a local density approximation calculation, we discuss the origin for the anisotropic bonding electron distribution around the Mn3+ ion in the low-temperature phase.