Study of spin-ordering and spin-reorientation transitions in hexagonal manganites through Raman spectroscopy.

Spin-wave (magnon) scattering, when clearly observed by Raman spectroscopy, can be simple and powerful for studying magnetic phase transitions. In this paper, we present how to observe magnon scattering clearly by Raman spectroscopy, then apply the Raman method to study spin-ordering and spin-reorientation transitions of hexagonal manganite single crystal and thin films and compare directly with the results of magnetization measurements. Our results show that by choosing strong resonance condition and appropriate polarization configuration, magnon scattering can be clearly observed, and the temperature dependence of magnon scattering can be simple and powerful quantity for investigating spin-ordering as well as spin-reorientation transitions.

Quantitation of fatty acid ethyl esters in human meconium by an improved liquid chromatography/tandem mass spectrometry.

This paper reports the development and validation of an improved assay for quantitation of fatty acid ethyl esters (FAEEs) in human meconium using liquid chromatography/tandem mass spectrometry (LC-MS/MS). FAAEs (ethyl laurate, ethyl myristate, ethyl palmitate, ethyl palmitoleate, ethyl stearate, ethyl oleate, ethyl linoleate, ethyl linolenate, and ethyl arachidonate) and the internal standard (I.S.

Effect of RGD-immobilized dual-pore poly(L-lactic acid) scaffolds on chondrocyte proliferation and extracellular matrix production.

Interactions between cell and polymer surface have great implications in tissue engineering. In this study, chondrocyte proliferation and matrix production were examined using porous poly(L-lactide) (PLLA) scaffolds that have different surface characteristics. PLLA scaffolds were prepared using a gas-foaming method, and subjected to surface modifications through plasma treatment and subsequent in situ grafting of hydrophilic acrylic acid (AA).

Poly (4-vinylimidazole) as nonviral gene carrier: in vitro and in vivo transfection.

We explored poly(4-vinylimidazole) (P4V) as a nonviral gene carrier. We show that P4V can form DNA condensates of small size (<110 nm) using a dye-exclusion assay with ethidium bromide and dynamic light scattering, and that the complexes form in a pH-sensitive manner, due to the amphotericity of the polymer. P4V was demonstrated to lead to transfection in vitro as effectively as polyethyleneimine (PEI), but at lower cytotoxicity, under conditions where higher amounts of either polymer are required, using luciferase and green fluorescent protein as examples.

High transfection efficiency of poly(4-vinylimidazole) as a new gene carrier.

Poly(4-vinylimidazole) (P4V) was obtained by free radical polymerization of 4-vinylimidazole (4V) prepared by decarboxylation of urocanic acid. P4V formed a complex with DNA that exhibited higher transfection effiency on Hela cells than polyethylenimine (PEI), through the proton sponge mechanism of the imidazole groups in the side chain of the P4V, and low cell toxicity.