Selectively degradable alternating copolymers of isobutyl vinyl ether and plant‐derived aldehydes with acyclic side chains: Effects of side group structures on copolymerization behaviors

Side group structures of aldehydes were demonstrated to have decisive effects on cationic copolymerizations with alkyl vinyl ether (VE). Alternating copolymerizations of isobutyl VE (IBVE) and plant‐derived aldehydes with acyclic side chains such as trans‐2,cis‐6‐nonadienal, trans‐2‐nonenal, and citral proceeded under appropriate reaction conditions with the EtSO₃H/GaCl₃ initiating system. In addition, some aldehydes copolymerized in a well‐controlled fashion to yield alternating copolymers with controlled molecular weights and narrow molecular weight distributions. Quantitative and selective acid hydrolysis of the resulting alternating copolymers, based on the acetal structures in the main chains, was also achieved to give other conjugated aldehydes as nearly sole degradation products. Copolymerization results of IBVE and various plant‐derived aldehydes with acyclic or cyclic side groups suggested that electron‐donating ability and bulkiness of the side groups were most likely responsible for the alternating and/or controlled copolymerization behaviors. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4684–4693     

Peumusolide A, unprecedented NES non-antagonistic inhibitor for nuclear export of MEK

A new polyketide peumusolide A was disclosed as an unprecedented NES non-antagonistic inhibitor for nuclear export of MEK, a promising scaffold for antitumor agents with novel mechanism of action, from Peumus boldus Molina. The absolute stereostructure as well as optical purity was established by use of the two synthesized enantiomeric model lactones. In addition, the Δε values in their CD spectra were demonstrated to be the conclusive index for determination of not only configuration at C-3 but also optical purity of natural congeneric polyketides. Peumusolide A was revealed to show NES non-antagonistic action by the biotinylated probe and to inhibit proliferation of MEK-activated tumor cells selectively.     

Aqueous chromatographic system for the quantification of propofol in biological fluids using a temperature-responsive polymer modified stationary phase

A new method for the quantitative analysis of monkey serum propofol, which is widely used as an anaesthetic agent, was developed by utilizing a temperature-responsive polymer of N-isopropylacrylamide (NIPAAm) and butyl methacrylate (BMA) as the stationary phase of HPLC–fluorescence detection. This poly(NIPAAm-co-BMA) copolymer undergoes a reversible phase transition from a hydrophilic to a hydrophobic microstructure when triggered by change in the temperature. Also this chromatographic system is possible to separate the analytes by using only water as a mobile phase. A pretreatment of the serum (80 μL) was only solid-phase extraction, and the recovery rate of propofol and internal standard was more than 77%, respectively. This method covered the calibration range from 0.5 μg/mL to 10 μg/mL and allowed a reproducible quantification of the serum propofol in administrated monkey serum. The intra- and inter-assay relative standard deviations were less than 14.1%. In addition, there was good relationship of the quantification values between the developed method and the widely used reversed-phase HPLC method. Our developed method has proven to be useful for a simple analysis of propofol in clinical practice, because the avoidance of complicated mobile phase preparation was possible, and only temperature changing could regulate the retention time of the analyte. In addition, by using water instead of fossil fuel, it is the ideal analytical method according to green chemistry.     

Contrarian investment strategy with data envelopment analysis concept

One of the typical issues in financial literature is that the market tends to be overly pessimistic about value stocks, many of which are past losers. Therefore, over-reactions might capture by measuring earnings surprise vary with past return levels. In this paper, we propose a new index for an effective investment strategy to capture the return-reversal effect using both Data Envelopment Analysis (DEA) and Inverted DEA in order to consider the above characteristics of the market. Our investment strategy using the new index exhibits better performance than the naive return-reversal strategy that only uses past returns or earnings surprise. In addition, the correlations between our new index and commonly used value indices are insignificant, and the value indices cannot represent the over-valued (under-valued) situations perfectly. Hence, considering both proposed and value indices like book-to-price one, we could select value stocks more effectively than by using only one of these indices.