Production of Lipids Containing High Levels of Docosahexaenoic Acid by a Newly Isolated Microalga, <Emphasis Type="Italic">Aurantiochytrium</Emphasis> sp. KRS101

In the present study, a novel oleaginous Thraustochytrid containing a high content of docosahexaenoic acid (DHA) was isolated from a mangrove ecosystem in Malaysia. The strain identified as an Aurantiochytrium sp. by 18S rRNA sequencing and named KRS101 used various carbon and nitrogen sources, indicating metabolic versatility. Optimal culture conditions, thus maximizing cell growth, and high levels of lipid and DHA production, were attained using glucose (60 g l⁻¹) as carbon source, corn steep solid (10 g l⁻¹) as nitrogen source, and sea salt (15 g l⁻¹). The highest biomass, lipid, and DHA production of KRS101 upon fed-batch fermentation were 50.2 g l⁻¹ (16.7 g l⁻¹ day⁻¹), 21.8 g l⁻¹ (44% DCW), and 8.8 g l⁻¹ (40% TFA), respectively. Similar values were obtained when a cheap substrate like molasses, rather than glucose, was used as the carbon source (DCW of 52.44 g l⁻¹, lipid and DHA levels of 20.2 and 8.83 g l⁻¹, respectively), indicating that production of microbial oils containing high levels of DHA can be produced economically when the novel strain is used.     

Improved high-efficiency organic solar cells via incorporation of a conjugated polyelectrolyte interlayer

The power conversion efficiencies of bulk heterojunction (BHJ) solar cells can be increased from 5 to 6.5% by incorporating an ultrathin conjugated polyelectrolyte (CPE) layer between the active layer and the metal cathode. Poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C(71) butyric acid methyl ester (PC(71)BM) were chosen for the photoactive layer. CPEs with cationic polythiophenes, in both homopolymer and block copolymer configurations, were used to improve the electronic characteristics. The significant improvement in device performance and the simplicity of fabrication by solution processing suggest a promising and practical pathway for improving polymer solar cells with high efficiencies.     

Quantification of tryptic peptides in quadrupole ion trap using high-mass signals derived from isotope-coded N-acetyl dipeptide tags

Isotope-labeled N-acetyl dipeptides (Ac-Xxx-Ala) are coupled to the primary amines of tryptic peptides and then analyzed by tandem mass spectrometry. Amide bond cleavage between Xxx and Ala provides both low- and high-mass isotope-coded signals for quantification of peptides. Especially, facile cleavage at the modified lysine side chain yields very strong high-mass quantitation signals in a noise-free region. Tagging tryptic peptides with isobaric N-acetyl dipeptides is a viable strategy for accurate quantification of proteins, which can be used with most quadrupole ion trap mass spectrometers carrying the 1/3 mass cut-off problem.     

Lateral and cross-lateral focusing of spherical particles in a square microchannel

The inertial migration of particles in micro-scale flows has received much attention due to its promising applications, such as the membrane-free passive separation of particles or cells. The particles suspended in rectangular channels are known to be focused near the center of each channel face as the channel Reynolds number (R(C)) increases due to the lift force balance and the hydrodynamic interactions of the particles with the wall. In this study, the three-dimensional positions of neutrally buoyant spherical particles inside a square microchannel are measured using the digital holographic microscopy technique, and a transition from the lateral tubular pinch to the cross-lateral focusing with increasing R(C) is reported. The particles are found to migrate first in the lateral direction and then cross-laterally toward the four equilibrium positions. A general criterion that can be used to secure the fully developed state of particle focusing in Lab-on-a-Chip applications is also derived. This criterion could be helpful for the accurate estimation of the design parameters of inertial microfluidic devices, such as R(C), channel length and width, and particle diameter.     

A highly reactive mononuclear non-heme manganese(IV)-oxo complex that can activate the strong C-H bonds of alkanes

A mononuclear non-heme manganese(IV)-oxo complex has been synthesized and characterized using various spectroscopic methods. The Mn(IV)-oxo complex shows high reactivity in oxidation reactions, such as C-H bond activation, oxidations of olefins, alcohols, sulfides, and aromatic compounds, and N-dealkylation. In C-H bond activation, the Mn(IV)-oxo complex can activate C-H bonds as strong as those in cyclohexane. It is proposed that C-H bond activation by the non-heme Mn(IV)-oxo complex does not occur via an oxygen-rebound mechanism. The electrophilic character of the non-heme Mn(IV)-oxo complex is demonstrated by a large negative ρ value of -4.4 in the oxidation of para-substituted thioanisoles.     

Structural properties of lithium thio-germanate thin film electrolytes grown by radio frequency sputtering

In this study, lithium thio-germanate thin film electrolytes have been successfully prepared by radio frequency (RF) magnetron sputtering deposition in Ar gas atmospheres. The targets for RF sputtering were prepared by milling and pressing appropriate amounts of the melt-quenched starting materials in the nLi(2)S + GeS(2) (n = 1, 2, and 3) binary system. Approximately 1 μm thin films were grown on Ni coated Si (Ni/Si) substrates and pressed CsI pellets using 50 W power and 25 mtorr (～3.3 Pa) Ar gas pressures to prepare samples for Raman and Infrared (IR) spectroscopy, respectively. To improve the adhesion between the silicon substrate and the thin film electrolyte, a sputtered Ni layer (～120 nm) was used. The surface morphologies and thickness of the thin films were determined by field emission scanning electron microscopy (FE-SEM). The structural properties of the starting materials, target materials, and the grown thin films were examined by X-ray diffraction (XRD), Raman, and IR spectroscopy.     

Spectroelectrochemistry of cytochrome c and azurin immobilized in nanoporous antimony-doped tin oxide

Stable immobilization of two redox proteins, cytochrome c and azurin, in a thin film of highly mesoporous antimony-doped tin oxide is demonstrated via UV-vis spectroscopic and electrochemical investigation.     

Biologically Relevant Metal-Cation Binding Induces Conformational Changes in Heparin Oligosaccharides as Measured by Ion Mobility Mass Spectrometry

Heparin interacts with many proteins and is involved in biological processes such as anticoagulation, angiogenesis, and antitumorigenic activities. These heparin-protein interactions can be influenced by the binding of various metal ions to these complexes. In particular, physiologically relevant metal cations influence heparin-protein conformations through electronic interactions inherent to this polyanion. In this study, we employed ion mobility mass spectrometry (IMMS) to observe conformational changes that occur in fully-sulfated heparin octasaccharides after the successive addition of metal ions. Our results indicate that binding of positive counter ions causes a decrease in collision cross section (CCS) measurements, thus promoting a more compact octasaccharide structure.