Intermolecular dynamics, interactions, and solvation in ionic liquids

Ionic liquids can simultaneously assume multiple solvent roles, because they are strongly polar and polarizable solvents and binary solutions and frequently contain very hydrophobic components. When the cation and anion functional groups are tuned appropriately, ionic liquids can be used as designer solvents for a broad range of applications. In this Account, we discuss our spectroscopic studies on the intermolecular interactions, dynamics, solvation, transport, and friction in ionic liquids, as compared with information obtained from macroscopic experiments including viscometry and calorimetry.     

Effects of dressing containing plant sterol on serum cholesterol concentration and the safety evaluation in borderline or mildly hypercholesterolemic Japanese subjects

In a placebo-controlled double-blind study, we examined the effects of dressing containing plant sterol (PS) on blood lipids and the safety in Japanese borderline or mildly hypercholesterolemic subjects. Fifty-nine subjects [total cholesterol (TC) concentration > or = 200 mg/dL] were randomly divided into two groups and were given daily 15 g of dressing containing 800 mg of PS [PS(+)-group] or without PS [PS(-)-group] for 12 weeks. Every 4 weeks, fasting blood was examined and subjective symptoms were analyzed. Serum TC, low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) concentrations did not change in the PS(-)-group, while TC and ApoB significantly decreased in the PS(+)-group at 8 and 12 weeks and LDL-C at 4, 8 and 12 weeks. Moreover, serum TC, LDL-C and ApoB concentrations were significantly lower than those of PS(-)-group at 8 and 12 weeks. Other laboratory tests were all in normal ranges and no adverse events were observed. The results indicated that PS-containing dressing decreased serum TC, LDL-C and ApoB concentrations in borderline or mildly hypercholesterolemic subjects. It is therefore proved that the dressing containing PS is helpful in maintaining blood cholesterol level normal and hence, the health of Japanese.     

Rapid Reconstitution of Biosynthetic Machinery for Fungal Metabolites in Aspergillus oryzae: Total Biosynthesis of Aflatrem

Reconstitution of the biosynthetic machinery for fungal secondary metabolites in Aspergillus oryzae provides an opportunity both for stepwise determination of the biosynthetic pathways and the total biosynthesis of fungal natural products. However, to maximize the utility of the reconstitution system, a simple and rapid strategy for the introduction of heterologous genes into A. oryzae is required. In this study, we demonstrated an effective method for introducing multiple genes involved in the biosynthesis of fungal metabolites by using the expression vectors pUARA2 and pUSA2, each of which contains two cloning sites. The successful introduction of all the aflatrem biosynthetic genes (seven genes in total) after two rounds of transformation enabled the total biosynthesis of aflatrem. This rapid reconstitution strategy will facilitate the functional analysis of the biosynthetic machinery of fungal metabolites.     

Identification of Proteins Modulated in the Date Palm Stem Infested with Red Palm Weevil (Rhynchophorus ferrugineus Oliv.) Using Two Dimensional Differential Gel Electrophoresis and Mass Spectrometry

A state of the art proteomic methodology using Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI TOF) has been employed to characterize peptides modulated in the date palm stem subsequent to infestation with red palm weevil (RPW). Our analyses revealed 32 differentially expressed peptides associated with RPW infestation in date palm stem. To identify RPW infestation associated peptides (I), artificially wounded plants (W) were used as additional control beside uninfested plants, a conventional control (C). A constant unique pattern of differential expression in infested (I), wounded (W) stem samples compared to control (C) was observed. The upregulated proteins showed relative fold intensity in order of I > W and downregulated spots trend as W > I, a quite interesting pattern. This study also reveals that artificially wounding of date palm stem affects almost the same proteins as infestation; however, relative intensity is quite lower than in infested samples both in up and downregulated spots. All 32 differentially expressed spots were subjected to MALDI-TOF analysis for their identification and we were able to match 21 proteins in the already existing databases. Relatively significant modulated expression pattern of a number of peptides in infested plants predicts the possibility of developing a quick and reliable molecular methodology for detecting plants infested with date palm.     

Mechanisms Underlying Decreased Hepatic Triacylglycerol and Cholesterol by Dietary Bitter Melon Extract in the Rat

In these studies, we focused on finding the mechanism(s) underlying the bitter melon (Momordica charantia L.) methanol fraction (MF)-dependent reduction in the concentration of hepatic triacylglycerol (TAG) and cholesterol in the rat. Rats were fed diets containing low (5 %) fat for 2 weeks (experiment 1), or low (5 %) and high (15 %) fat for a longer period of 8 weeks (experiment 2). MF was supplemented at 1 % level in both experiments. After feeding, rats were sacrificed, and their livers were prepared as slices and hepatocytes, followed by incubation with [1(2)-¹⁴C] acetate or [1-¹⁴C] oleic acid (18:1 n-6). Under these conditions, we found that rats fed diets containing MF, as compared to those without MF, showed: (1) no adverse effects on food intake and growth, (2) a decreased hepatic TAG and total cholesterol, irrespective of the difference in dietary fat level or feeding period, and (3) a decreased incorporation of [1(2)-¹⁴C] acetate and [1-¹⁴C] oleic acid into TAG of liver slices and hepatocytes. MF-supplemented rats also showed no altered incorporation of labeled acetate into cholesterol and cholesterol ester, an increased fecal excretion of neutral steroids, but not of acidic steroids, and an enhanced mRNA abundance of carnitine palmitoylacyltransferase I, which is the rate-limiting enzyme for fatty acid oxidation. These results suggest that dietary MF decreases hepatic TAG synthesis while enhancing fatty acid oxidation, thereby reducing the concentration of hepatic TAG. The liver cholesterol-lowering effect of MF, however, is probably mediated through an increased fecal excretion of neutral steroids, without an effect on cholesterogenesis.     

Enhancing low-temperature energy harvesting by lead-free ferroelectric Ba(Zr0.1Ti0.9)O3

The energy-harvesting ability of the lead-free ferroelectric Ba(Zr,Ti)O₃ was investigated and greatly enhanced using the Kim novel electrothermodynamic cycle for low-temperature application. Ba(Zr,Ti)O₃ was synthesized with a Zr:Ti ratio of 10:90 (BZT10) by hot-press sintering, which exhibited a mix relaxor-ferroelectric behavior. For power generation using the Kim cycle with low and high temperatures of T_L = 25°C, T_H = 120°C, the most optimized temperature pattern occurred for a heating time of 12.5 s and a cooling time of 22.5 s. Under these conditions, the electric field increased during the novel isodisplacement process, and the displacement variation in the isoelectric step reached the highest value and maximized the BZT10 cycle loop area. Applying these conditions while lowering T_L to 20°C, an energy density N_D = 504 mJ/cm³ was achieved. This value is the highest obtained energy density in a practical test for lead-free ferroelectric bulk material in the BaTiO₃ family.     

Advanced Sn/C composite anodes for lithium ion batteries

Metallic tin was deposited in fine particulate form on the surface of carbonaceous mesophase spherules (CMS) and in the pores of porous carbon by the decomposition and reduction of tin(II) 2-ethylhexanoate at 450 °C. The Sn/C composite powders obtained were used as anode materials for lithium ion cells. Electrochemical cycling tests of coin cells show that the dispersion of tin into the carbonaceous materials enhances the reversible capacity of the electrodes. The capacity retention at the 50th cycle is 91 % for Sn/CMS composite containing 22% tin, against 428 mAh g^–1 at the first cycle. With further increase in tin content, the capacity fade upon cycling is more rapid.     

Intramolecular triplet energy migration in poly(2-vinylnaphthalene) and poly(naphthylalkyl methacrylate)s in solid solution: Effects of side chain length

Summary The effect of side chain length on intramolecular triplet energy migration of naphthalene containing polymers was investigated by a delayed fluorescence (DF) spectroscopy for the solid solution of the polymers. The degree of triplet energy migration depends strongly on whether the chromophores are directly attached to the main chain or not.     

Production of 5,8,11-cis-eicosatrienoic acid by a Δ12-desaturase-defective mutant ofMortierella alpina 1S-4

A mutant defective in Δ12-desaturase of an arachidonic-acid producing fungus,Mortierella alpina 1S-4, was shown to be a novel potent producer of Mead acid (5,8,11-cis-eicosatrienoic acid, 20:3ω9). The fungus produced several fatty acids of the n-9 family,i.e., 6,9-cis-octadecadienoic acid (18:2ω9), 8,11-cis-eicosadienoic acid (20:2ω9) and 20:3ω9. Significantly high levels of these fatty acids were produced during growth at low temperatures (12–20°C). On submerged cultivation at 20°C for 10 days in a 5-L fermenter containing 2% glucose plus 1% yeast extract (pH 6.0), the production of 20:3ω9 reachedca. 0.8 g/L (56 mg/g dry mycelia), accounting for 15% (by wt) of the total mycelial fatty acids. The other major fatty acids were palmitic acid (6%), stearic acid (11%), oleic acid (45%), 18:2ω9 (12%) and 20:2ω9 (3%). Studies on the distribution of fatty acids among lipid classes showed that, irrespective of the growth temperature employed (12–28°C),ca. 70% (by mol) of 20:3ω9 was present in the triglyceride and the remainder in the phospholipid fraction, especially in phosphatidylcholine (PC). When the fungus was grown at 12°C, the proportion of 20:3ω9 in the PC fraction wasca. 55%. On leave from Suntory Ltd.     

Band Gap Modification of Diamond Photonic Crystals by Changing the Volume Fraction of the Dielectric Lattice

Photonic crystals with a diamond structure of epoxy lattices in which TiO₂-based ceramic particles are dispersed were fabricated by stereolithography. The periodicity of the lattice was designed to reflect electromagnetic waves in the gigahertz range. The volume fraction (β) of the dielectric lattice medium was modified from 14% to 33% by changing the rod diameter of the lattice. The photonic band gap was observed along Γ-L 〈111〉, Γ-X 〈100〉, and Γ-K 〈110〉 directions and the complete photonic band gap was formed at over β= 20%. The width of the forbidden gap increased gradually when the β increased over 14%, and reached 2.4 GHz at β= 33%. These results agreed with the band calculation using the plane wave expansion method.