Side chain-directed assembly of triangular molecular panels into a tetrahedron vs. open cone

Despite their structural similarity, triangular tetradentate ligands 2b and 2c experience different assembly pathways on complexation with (en)Pd(NO3)2 to give M8L4 tetrahedral (3) and open cone (4) structures, respectively, due to steric restriction by side chains at the corner or on the edge of the ligands.     

Fast and quantitative analysis of branched-chain amino acids in biological samples using a pillar array column

In this study, a fast and quantitative determination method for branched-chain amino acids (BCAAs), namely leucine, isoleucine, and valine, was developed using a pillar array column. A pillar array column with low-dispersion turns was fabricated on a 20?×?20-mm² microchip using multistep ultraviolet photolithography and deep reactive ion etching. The BCAAs were fluorescently labeled with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), followed by reversed-phase separation on the pillar array column. The NBD derivatives of the three BCAAs and an internal standard (6-aminocaproic acid) were separated in 100 s. The calibration curves for the NBD-BCAAs had good linearity in the range of 0.4–20 μM, using an internal standard. The intra- and interday precisions were found to be in the ranges of 1.42–3.80 and 2.74–6.97 %, respectively. The accuracies for the NBD-BCAA were from 90.2 to 99.1 %. The method was used for the analysis of sports drink and human plasma samples. The concentrations of BCAAs determined by the developed method showed good agreements with those determined using a conventional high-performance liquid chromatography system. As BCAAs are important biomarkers of some diseases, these results showed that the developed method could be a potential diagnostic tool in clinical research.     

Magnetic properties of the amorphous alloy Fe80Er20

Amorphous Fe₈₀Er₂₀ alloys were prepared with the melt spinning technique. The ribbons were investigated by Mössbauer spectroscopy from room temperature to 4.2 K. A phase transition from the paramagnetic to the ferromagnetic phase could be observed. The temperature dependence of the internal magnetic field was measured. The correlations of the hyperfine parameters were determined from the 4.2 K spectrum.     

Selective INEPT,a new technique for the 13C NMR assignment of methylene carbons with non-equivalent protons,and its application to the analysis of the 13C NMR spectrum of monensin

A new method based on the combination of selective proton decoupling and INEPT is explained in detail. This technique, named selective INEPT (SEL-INEPT), is a useful and sensitive method for the ¹³C NMR assignment of methylene carbons with non-equivalent protons. The ¹³C NMR spectrum of monensin has been analysed by the application of this technique.     

Magnetic and mechanical properties of amorphous Fe-Y alloys

The magnetic and mechanical properties of amorphous Fe_100−xY_x alloys (20 ≤ x ≤ 60) fabricated by rapid quenching have been measured. The dependence of the density, Young's modulus and magnetic moment per Fe atom on x shows a break point between x = 30 and 40, accompanied by a drastic change in the X-ray diffraction pattern. The spontaneous volume magnetostriction as well as the forced volume magnetostriction are a maximum at x = 20 and decrease rapidly with increasing x. The variation of the magnetic and mechanical properties with x is explained by a change of the local atomic arrangement in the amorphous state, reflecting the structure of corresponding crystalline compounds.     

Capillary zone electrophoretic determination of iodide in seawater using transient isotachophoresis with artificial seawater as the background electrolyte

We describe an application of capillary zone electrophoresis (CZE) with transient isotachophoresis (ITP) as the on-line concentration procedure for the determination of iodide in seawater. The effective mobility of iodide was decreased by the addition of 10 mM cetyltrimethylammonium chloride (CTAC) to an artificial seawater background electrolyte (BGE) so that transient ITP functioned and iodide was separated from other coexisting anions such as bromide, nitrite, and nitrate in seawater samples. After sample injection, 600 mM acetate was separately injected into the capillary as the terminating ion to generate transient ITP. The limit of detection (LOD) for iodide was 3.0 microg/L. The LOD was obtained at a signal-to-noise ratio (S/N) of 3. The values of the relative standard deviation (RSD) of peak area, peak height, and migration time for iodide were 2.9, 2.1, and 0.6%. The proposed method was applied to the determination of iodide in seawater collected around the Osaka Bay. The results obtained by use of the calibration graph were agreed with those obtained by the addition of the standard solutions for iodide.     

In situ magnetic hysteresis measurement of magnetic tips in magnetic force microscope

In situ magnetic hysteresis measurements of magnetic tips in a magnetic force microscope (MFM) are demonstrated using alternating gradient force magnetometry. The measured magnetic moments of MFM tips are estimated in the range from 10⁻⁶ to 10⁻⁵ emu by this technique and the whole MFM tips in cantilevers are considered to be measured from the value of measured magnetic moments. The relationship between the magnetic hysteresis loops of MFM tips and those of coated magnetic films is discussed.     

Effect of the effective anisotropy field of soft layer on magnetic properties of soft/hard stacked media

Magnetic properties of soft/hard stacked perpendicular magnetic recording media were investigated using a two-moment model with taking account of demagnetizing energy. Demagnetizing energy of the soft layer may improve the uniformity of magnetic properties of the composite media and also decrease the interlayer thickness, although weaken the thermal stability a little. The application of high saturation magnetization (M_s) soft magnetic material as the soft layer may compensate for the undesirable contribution while maintaining its benefits.