Highly phosphonated poly(N‐phenylacrylamide) for proton exchange membranes

A novel highly phosphonated poly(N‐phenylacrylamide) ( PDPAA ) with an ion‐exchange capacity (IEC) of 6.72 mequiv/g was synthesized by the radical polymerization of N‐[2,4‐bis(diethoxyphosphinoyl)phenyl]acrylamide ( DEPAA ), followed by the hydrolysis with trimethylsilyl bromide. Then, the crosslinked PDPAA membrane was successfully prepared by the electrophilic substitution reaction between the aromatic rings of PDPAA and the carbocation formed from hexamethoxymethylmelamine (CYMEL) as a crosslinker in the presence of methanesulfonic acid. The crosslinked PDPAA membrane had high oxidative stability against Fenton's reagent at room temperature. The proton conductivity of the crosslinked PDPAA membrane was 8.8 × 10^?2 S/cm at 95% relative humidity (RH) and 80 °C, which was comparable to Nafion 112. Under low RH, the crosslinked PDPAA membrane showed the proton conductivity of 1.9 × 10^?3 and 4.7 × 10^?5 S/cm at 50 and 30% RH, respectively. The proton conductivity of the crosslinked PDPAA membrane lied in the highest class among the reported phosphonated polymers, and, consequently, the very high local concentration of the acids of PDPAA (IEC = 6.72 mequiv/g) achieved high and effective proton conduction under high RH. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Stress-strain behavior of segmented polyurethaneureas under pure shear deformation

Elastic properties of segmented polyurethaneureas (SPUs) under pure shear deformation were investigated. Data were analyzed by using strain energy density function (W). The values of the derivatives of W with respect to the invariants of the strain tensor (I _i ; i = 1, 2, 3 ) at zero strain limit were also estimated theoretically and were compared with those estimated by experiment. The limiting value of the derivative with respect to I ₁ (W/I ₁) was shown theoretically to be 5 G/8, while the derivatives with respect to I ₂ and I ₃ (W/I ₂ and W/I ₃ were respectively-G/8 and -3G/8. The theoretical prediction could explain the asymptotic behavior of the derivatives of SPUs as well as isoprene rubber (IR) reported by Kawabata et al. at small I ₁ limit.     

Sm atomic dynamics in a charge density wave compound SmNiC2

¹⁴⁹Sm nuclear resonant inelastic scattering was carried out in a charge density wave compound SmNiC₂. We have investigated temperature dependences of the Sm partial phonon density of states and recoil-free fraction at the Sm site and the average sound velocity estimated from the Sm partial density of states. The Sm partial density of states exhibits temperature dependence, suggesting that the phonon modes between 20 and 25 meV may correlate with the charge density wave. Temperature dependence of the recoil-free fraction is difficult to prove the correlation with either the charge density wave or ferromagnetic ordering. The average sound velocity obtained by the Sm partial phonon density of states exhibits temperature dependence, agreeing qualitatively with very recent elastic constant measurements.     

In situ Raman imaging of osteoblastic mineralization

Hydroxyapatite (HA) is synthesized at early stages of bone formation by osteoblasts. Nondestructive observation of early stages of osteoblastic mineralization provides crucial information for biological mechanism of bone formation. Raman microscopy serves as an ideal tool to observe the osteoblastic mineralization process because it shows the chemical information of the sample at a minimally invasive level. In addition, HA is a marker for osteoblastic mineralization, and HA Raman signal is strong enough to identify mineralized spots in osteoblasts. In this research, we visualized the distribution of HA in cultured mouse osteoblasts by Raman imaging and observed the location of the mineralized spots in the culture. We monitored HA Raman signal from osteoblast culture for 3 days after administrating the osteogenic differentiation medium and observed Raman signal associated with HA. We identified mineralized spots of KUSA‐A1 by Raman imaging constructed from the distribution of HA Raman signal. We successfully visualized the distribution of the mineralized spots in the culture of KUSA‐A1. We compared our Raman images with Alizarin red S staining assay, which was a conventional method to evaluate the mineralization process. Raman imaging of the KUSA‐A1 culture visualized the mineralized spots more accurately than Alizarin red S staining assay. Raman imaging of HA serves as a powerful tool to identify the mineralized spots in an in vitro culture of osteogenic lineage cells. Copyright © 2014 John Wiley & Sons, Ltd.     

Fluorescence-monitored zero dead-volume nanoLC-microESI-QIT-TOF MS for analysis of fluorescently tagged glycosphingolipids

An analysis of the glycan processing event is of particular importance to understand the nontemplate dependent synthetic mechanism of the multiple glycosylation reactions taking place in the Golgi apparatus in connection with the post-translational modification of biomolecules. In our efforts to address the issue, we constructed an analysis platform using nano-liquid chromatography (LC), which also worked as a spray tip, with an optical-fiber-based blue (470 nm) light emitting diode (LED)-induced fluorescence (520 nm) detector coupled with a microelectrospray ionization (ESI)-quadrupole ion trap (QIT)-time of flight (TOF) mass spectrometer (MS). This system was designed to enable both quantitative and qualitative analyses of fluorescently tagged molecules such as BODIPY-tagged lactosylceramide. Owing to the zero dead volume after LC separation, an extremely high sensitivity was achieved for the quantitative analysis (260 amol). It was also shown that a simultaneous online structural analysis based on MS could be achieved for the same quantity of analyte. To further demonstrate its potential, an enzymatic reaction of fluorescently tagged lactosylceramide using sialyltransferase was carried out, and the conversion yield was obtained on the basis of fluorescence detection. In addition, the structural details of a product, sialyl lactosylceramide, were obtained by MS and MS/MS analyses.     

A fluorescent single domain antibody against plumbagin expressed in silkworm larvae for fluorescence-linked immunosorbent assay (FLISA)

A fluorescent single-domain antibody (fluobody), a chimera of a green fluorescent protein (AcGFP) with a single chain variable fragment antibody (scFv), against plumbagin (5-hydorxy-2-methyl-1,4-naphthoquinone; PL) was successfully expressed in the hemolymph of silkworm larvae using a Bombyx mori nucleopolyhedrovirus (BmNPV) bacmid DNA system to develop a rapid, simple, and sensitive fluorescence-linked immunosorbent assay (FLISA). In this study, two kinds of fluobody, in which the PL-scFv was fused at the N-terminus (N-fluobody) or C-terminus of AcGFP (C-fluobody), were expressed in silkworm larvae for comparative purposes. Interestingly, both fluobodies expressed in the BmNPV bacmid DNA system retained both of their original functions as an AcGFP and a PL-scFv, although the functions of the N-fluobody were found to be inferior to those of C-fluobody when they were expressed in Escherichia coli. Moreover, an improvement in the limit of quantification for PL measurement was observed in FLISA (24 ng mL(-1)) compared with conventional ELISA (0.2 μg mL(-1)). Since both the C-fluobody and N-fluobody are useful probes for FLISA and the time-, cost-consuming refolding step required in the conventional bacterial expression system can be avoided when they are expressed in the BmNPV bacmid DNA system, the silkworm expression system is useful for expressing fluobodies when developing FLISA.     

Development of a combined technique using a rapid one-step immunochromatographic assay and indirect competitive ELISA for the rapid detection of baicalin

A colloidal gold conjugated anti-baicalin monoclonal antibody (anti-BA MAb) was prepared and used in an immunochromatographic assay (ICA) for BA in Scutellariae Radix and Kampo medicines. This competitive ICA uses an anti-BA MAb which shows a high specificity for BA and baicalein. Its advantages include a short assay time (15 min), no dependence on any instrumental systems, and it can detect BA in plant materials and Kampo medicines. The limit of detection for the ICA was found to be around 0.6 μg mL⁻¹of baicalin. Moreover, the usefulness of the combination of indirect competitive ELISA and the ICA using anti-BA MAb as a quality control method was confirmed for analysis of BA in Scutellariae Radix and Kampo medicines with a sufficient sensitivity (200 ng mL⁻¹ to 2 μg mL⁻¹), obtainable in an easy and timely manner.     

Discovery of a novel acyl-CoA: cholesterol acyltransferase inhibitor: the synthesis, biological evaluation, and reduced adrenal toxicity of (4-phenylcoumarin)acetanilide derivatives with a carboxylic acid moiety

As a part of our research for novel potent and orally available acyl-CoA: cholesterol acyltransferase (ACAT) inhibitors that can be used as anti-atherosclerotic agents, we recently reported the discovery of the (4-phenylcoumarine)acetanilide derivative 1. However, compound 1 showed adrenal toxicity in animal models. In order to search for safer ACAT inhibitors that do not have adrenal toxicity, we examined the inhibitory activity of ACAT in human macrophage and adrenal cells. The introduction of a carboxylic acid moiety on the pendant phenyl ring and the adjustment of the lipophilicity led to the discovery of (2E)-3-[7-chloro-3-[2-[[4-fluoro-2-(trifluoromethyl)phenyl]amino]-2-oxoethyl]-6-methyl-2-oxo-2H-chromen-4-yl]phenyl]acrylic acid (21e), which showed potent ACAT inhibitory activity in macrophages and a selectivity of around 30-fold over adrenal cells. In addition, compound 21e showed high adrenal safety in guinea pigs.     

Adsorption of ytterbium onto Saccharomyces cerevisiae fungal cells: A pH-dependent contribution of phosphoryl functional group

The adsorption of ytterbium on the cells of yeast Saccharomyces cerevisiae has been studied by batch type experiment by changing solution pH. The Yb adsorption species on the yeast cell wall of the S. cerevisiae was determined by extended X-ray absorption fine structure spectroscopy combined with a linear combination analysis at various pHs. The results indicated that the contribution of Yb-phosphoryl species was constant between pH 3 and 5, strongly suggesting that most of the Yb was associated with undeprotonated phosphoryl functional groups.     

Improved efficiency and product selectivity in the photo-Claisen-type rearrangement of an aryl naphthylmethyl ether using a microreactor/flow system

Ultraviolet (UV) irradiation of 2-[(2,4,6-trimethylphenoxy)methyl]-1-(methoxycarbonyl)naphthalene promotes a photochemical reaction that gives a cyclohexa-2,4-dienone product arising from a photo-Claisen-type ortho-rearrangement and a phenol derivative arising from a meta-rearrangement, along with 1-methoxycarbonyl-2-methylnaphthalene and 1,2-bis[1-(methoxycarbonyl)naphthalen-2-yl]ethane. When this process is carried out in a microreactor/flow system, its efficiency is dramatically enhanced and selectivity of products is improved. The effects on efficiency and product selectivity caused by the microreactor/flow system are attributed to more efficient light absorption and the suppression of secondary reactions.