Pharmacokinetics of brain natriuretic peptide in rats.

The pharmacokinetics of rat brain natriuretic peptide (rBNP) was compared with that of alpha-rat atrial natriuretic peptide (alpha-rANP) in rats. After intravenous infusion in rats (600 pmol min-1kg-1 for 2 min), the disappearance of plasma rBNP was 4-fold slower than that of alpha-rANP. The estimated mean plasma clearance rates for rBNP and alpha-rANP were 45.9 ml min-1kg-1 and 74.4 ml min-1kg-1, respectively. The affinity of rBNP for the clearance receptor or degradation enzyme was considered to be lower than that of alpha-rANP.     

Selective foam separation of binary protein solution by SDS complexation method

A fundamental study about the selective foam separation of protein mixture was carried out. A solution containing two proteins, ovalbumin (OA) and lysozyme (LZ), and an anionic surfactant, sodium dodecyl sulfate (SDS), was adjusted to pH 6.0, which referred to an intermediate state between the isoelectric points of the proteins. The solution was processed by continuous foam separation. The results showed that a proper addition of SDS greatly improved the selective recovery of LZ to OA. The experimental data were well explained by a simple model that most of cationic protein molecules (LZ) are associated with SDS and the adsorption of all the species including LZ-SDS complexes are subjected to Langmuir adsorption isotherm. The results also showed that one of the Langmuir parameters, which means a kind of lyophillic property of adsorbed material, of LZ-SDS complexes was extremely large as compared with that of primary protein.     

Diffusion Monte Carlo study of correlation in the hydrogen molecule

The diffusion Monte Carlo (DMC) method shows that correlation in H₂ produces a set of three spatial changes: (i) an enhancement in the electron density distribution n( r ) in the left and right anti‐binding regions that include separately the immediate vicinity of each of the two nuclei, (ii) a reduction in n( r ) in the binding region intervening between the two nuclei as a counterbalance, and (iii) a concomitant increase in the equilibrium internuclear separation. It is stressed that the correlation energy E^c (= T^c + V^c) for diatomic molecules be defined by the difference in the total energy between the exact and the Hartree–Fock (HF) variational calculations that are performed at individually optimized internuclear separations. It is this definition that makes it possible to involve a significant contribution from a correlation‐induced change in the equilibrium internuclear separation as part of the correlation energy and to relate (i) and (ii) to (iii) in consistency with the electrostatic theorem. The present calculations fulfill the virial theorem to an accuracy of ?V/T = 2.00 for DMC and ?V^HF/T^HF = 2.000 for HF. The present correlation energy E^c = ?0.0408 hartree is not only in good agreement with the most accurate value previously reported, but also can be analyzed into all its components in accordance with the correlational virial theorem 2T^c + V^c = 0. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Cationic oligomerization of anethole: Selective synthesis of dimers and trimers

A linear unsaturated dimer of anethole [II, (E)-1,3-bis(p-methoxyphenyl)-2-methylpentene-1], was prepared in 98% yield with an acetyl perchlorate (AcClO₄) catalyst in a nonpolar solvent (C₆H₆) at a high temperature (70°C). At 0°C a linear unsaturated trimer was formed in high yield with dimer II. The geometric structure of the linear unsaturated dimers was determined by analysis of the nuclear Overhauser effect (NOE) on their ¹H-NMR spectra. NOE analysis showed that at 0°C with AcClO₄, trans-anethole gives the (E)-form (II), whereas cis-anethole yields the (Z)-form. On the other hand, with a metal-halide catalyst (BF₃OEt₂) a cyclic dimer and a cyclic trimer were produced in high yields in a polar solvent [(CH₂Cl₂)] at 70°C; higher oligomers (≥ tetramer) were scarcely formed. The effect of catalysts on the structure of oligomers was explained in terms of the interaction between a growing carbocation and a counterion.     

Simultaneous determination of testosterone, cortisol, and dehydroepiandrosterone in saliva by stable isotope dilution on-line in-tube solid-phase microextraction coupled with liquid chromatography–tandem mass spectrometry

We have developed a simple and sensitive method for the simultaneous determination of testosterone (TES), cortisol (CRT), and dehydroepiandrosterone (DHEA) in saliva by automated online in-tube solid-phase microextraction (SPME) coupled with liquid chromatography–tandem mass spectrometry (LC–MS/MS) using a Discovery HS F5 column. The optimum in-tube SPME conditions were 25 draw/eject cycles of 40 μL of sample at a flow rate of 200 μL/min using a Supel-Q PLOT capillary column as an extraction device. The extracted compounds were easily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. The in-tube SPME LC–MS/MS method showed good linearity with correlation coefficients r?≥?0.9998 for TES, CRT, and DHEA using their respective stable isotope-labeled internal standards. The intra-day and inter-day precisions (relative standard deviations) were below 4.9 and 8.5 % (n?=?5), respectively. This method was successfully utilized to analyze TES, CRT, and DHEA in saliva samples without any other pretreatment or interference peaks, and the quantification limits (S/N?=?10) of TES, CRT and DHEA were about 0.01, 0.03 and 0.29 ng/mL saliva, respectively. The recoveries of these compounds spiked into saliva samples were each above 94 %. This method was applied to analyze changes in salivary TES, CRT, and DHEA levels resulting from stress and fatigue load.     

Highly efficient cryogenically-cooled Yb:YAG laser

A MOPA laser system for high pulse energy and high average power has been developed by using a cryogenic Yb:YAG. In the regenerative amplifier with our original TRAM architecture, the high pulse energies of 6.5 and 1.5 mJ were obtained at the repetition rate of 200 Hz and 1 kHz, respectively. An optical efficiency was as high as η_o-o = 9.3% with an excellent beam quality of M ² < 1.1, which ensured that a cryogenic Yb:YAG TRAM had a high thermal strength. The following four pass power amplifier with a cryogenic Yb:YAG rod showed 140 mJ at 100 Hz. Both a high optical efficiency of η_o-o = 30% and a high slope efficiency of η_s = 44% showed that an efficient laser operation could be realized for a power amplification with both a high pulse energy and a high average power by using a cryogenic Yb:YAG.