Quantitative determination of paclitaxel and its metabolites, 6α‐hydroxypaclitaxel and p‐3′‐hydroxypaclitaxel,in human plasma using column‐switching liquid chromatography/tandem mass spectrometry

A column‐switching liquid chromatography/electrospray ionization tandem mass spectrometry to determine paclitaxel and its metabolites, 6α‐hydroxypaclitaxel and p‐3′‐hydroxypaclitaxel, in human plasma was developed. The analytical system had a Shim‐Pack MAYI‐ODS (10 × 4.6 mm i.d.) trapping column with deproteinization ability that concentrates analytes and removes water‐soluble components. This method covered a linearity range of 5–5000 ng/mL of concentrations in plasma for paclitaxel, a range of 0.87–870 ng/mL for 6α‐hydroxypaclitaxel and a range of 0.87–435 ng/mL for p‐3′‐hydroxypaclitaxel. The intra‐day precision and inter‐day precision of analysis were less than 11.1%, and the accuracy was within ±14.4% at concentrations of 5, 50, 500 and 5000 ng/mL for paclitaxel, 0.87, 8.7, 87 and 870 ng/mL for 6α‐hydroxypaclitaxel, and 0.87, 8.7, 87 and 435 ng/mL for p‐3′‐hydroxypaclitaxel. The total run time was 30 min. Our method was successfully applied to clinical pharmacokinetic investigation. Copyright © 2012 John Wiley & Sons, Ltd.     

Reliability study on high-power 638nm broad stripe laser diode

High-power laser diodes (LDs) are strongly demanded as a light source of display applications. In this work, the reliability of a high-power 638 nm broad stripe (BS) LD was studied from the viewpoint of not only gradual degradation but also catastrophic optical degradation (COD) at a front facet. Long term acceleration aging tests for the 638 nm BS-LD with the window-mirror structure by using Zn diffusion were performed. It was confirmed that COD only occurs at a high output power and this mode was dominant compared with gradual degradation. The result also revealed that the mean time to failure due to COD was proportional to optical density to the power of ?3:2. It is clarified that maintaining a low optical output power density is essential to develop high-power and highly reliable red BS-LDs.     

Development of a Terpenoid Alkaloid‐like Compound Library Based on the Humulene Skeleton

Many natural terpenoid alkaloid conjugates show biological activity because their structures contain both sp³‐rich terpenoid scaffolds and nitrogen‐containing alkaloid scaffolds. However, their biosynthesis utilizes a limited set of compounds as sources of the terpenoid moiety. The production of terpenoid alkaloids containing various types of terpenoid moiety may provide useful, chemically diverse compound libraries for drug discovery. Herein, we report the construction of a library of terpenoid alkaloid‐like compounds based on Lewis‐acid‐catalyzed transannulation of humulene diepoxide and subsequent sequential olefin metathesis. Cheminformatic analysis quantitatively showed that the synthesized terpenoid alkaloid‐like compound library has a high level of three‐dimensional‐shape diversity. Extensive pharmacological screening of the library has led to the identification of promising compounds for the development of antihypolipidemic drugs. Therefore, the synthesis of terpenoid alkaloid‐like compound libraries based on humulene is well suited to drug discovery. Synthesis of terpenoid alkaloid‐like compounds based on several natural terpenoids is an effective strategy for producing chemically diverse libraries.     

Attitudes and preferences: Approaches to representing decision maker desires

Informative interrelationships between attitudes and preferences when formally studying a conflict within the framework of the Graph Model for Conflict Resolution are specified through the development of formal theorems. Specifically, the parallel nature of attitudes and preferences is illuminated to show how attitudes can provide a simple way to more effectively represent complex preference structures when decision makers hold concern for other decision makers’ interests. To illustrate this important property of attitudes, the Graph Model for Conflict Resolution is applied to the negotiation over the sale of a brownfield property both with and without attitudes.     

Quantum tautomerization in porphycene and its isotopomers: Path-integral molecular dynamics simulations

Path-integral molecular dynamics simulations have been performed for porphycene and its isotopic variants in order to understand the effect of isotopic substitution of inner protons on the double proton transfer mechanism. We have used an on-the-fly direct dynamics technique at the semiempirical PM6 level combined with specific reaction parameterization. Our quantum simulations show that double proton transfer of the unsubstituted porphycene at T = 300 K mainly occurs via a so-called concerted mechanism through the D_2h second-order saddle point. In addition, we found that both isotopic substitution and temperature significantly affect the double proton transfer mechanism. For example, the contribution of the stepwise mechanism increases with a temperature increase. We have also carried out hypothetical simulations with the porphycene configurations being completely planar. It has been found that out-of-plane vibrational motions significantly decrease the contribution of the concerted proton transfer mechanism.     

Wavy texture in pressure-driven startup flows of liquid crystalline polymer solutions through a slit cell: effects of polymer concentration and solution temperature

Dependences of wavy texture on polymer concentration and solution temperature were examined using aqueous solutions of hydroxypropylcellulose (HPC). The phase of aqueous solution of HPC varied from an isotropic (I) system to a liquid crystalline (LC) one through a biphasic (I+LC, LC+I) system with increasing the HPC concentration and/or decreasing the solution temperature. The wavy texture emerged not only in the LC system but also in the LC+I system. Furthermore, induction time of wavy texture was evaluated in terms of apparent shear strain. It is suggested that polydomain structures included in liquid crystalline systems and droplets of isotropic phase in biphasic systems affect the initial stage of emergence of wavy texture at low shear rates.