Effects of oligoDNA template length and sequence on binary self-assembly of a nucleotide bolaamphiphile

Templated self-assembly of nucleotide bolaamphiphile 1 (in which a 3'-phosphorylated thymidine moiety is connected to each end of a long oligomethylene chain) with a 10-, 20-, 30-, or 40-meric single-stranded oligoadenylic acid (2, 3, 4, or 5) led to the formation of right-handed helical nanofibers in 0.1x Tris/EDTA (TE) buffer solutions. The helical pitch increased as the length of the oligoadenylic acid template increased. DNA composed of oligoadenylic and oligocytidylic acid sequences (6, 7, and 8) also acted as templates to induce the formation of helical nanofiber structures. The diameter of the nanofibers remained constant (6-6.6 nm) irrespective of the template used. The binary self-assembly of 1 with 4 also produced higher-order, double-stranded nanofibers.     

Infrared photodissociation spectroscopy of Al(+)(CH(3)OH)(n) (n = 1-4)

Infrared photodissociation spectra of Al(+)(CH(3)OH)(n) (n = 1-4) and Al(+)(CH(3)OH)(n)-Ar (n = 1-3) were measured in the OH stretching region, 3000-3800 cm(-1). For n = 1 and 2, sharp absorption bands were observed in the free OH stretching region, all of which were well reproduced by the spectra calculated for the solvated-type geometry with no hydrogen bond. For n = 3 and 4, there were broad vibrational bands in the energy region of hydrogen-bonded OH stretching vibrations, 3000-3500 cm(-1). Energies of possible isomers for the Al(+)(CH(3)OH)(3),4 ions with hydrogen bonds were calculated in order to assign these bands. It was found that the third and fourth methanol molecules form hydrogen bonds with methanol molecules in the first solvation shell, rather than a direct bonding with the Al(+) ion. For the Al(+)(CH(3)OH)(n) clusters with n = 1-4, we obtained no evidence of the insertion reaction, which occurs in Al(+)(H(2)O)(n). One possible explanation of the difference between these two systems is that the potential energy barriers between the solvated and inserted isomers in the Al(+)(CH(3)OH)(n) system is too high to form the inserted-type isomers.     

Total synthesis of borrelidin

The total synthesis of borrelidin has been achieved. The best feature of our synthetic route is macrocyclization at C11-C12 for the construction of an 18-membered ring after esterification between two segments. A detailed examination of the macrocyclization led us to the samarium(II) iodide-mediated intramolecular Reformatsky-type reaction as the most efficient synthetic approach. The two key segments were synthesized through regioselective methylation, directed hydrogenation, stereoselective Reformatsky-type reaction, and MgBr2.Et2O-mediated chelation-controlled allylation.     

Lower closure point of adsorption hysteresis in ordered mesoporous silicas

To examine the nature of the lower closure point of adsorption hysteresis in ordered mesoporous silicas, we measured the temperature dependence of the adsorption-desorption isotherm of nitrogen for three kinds of ordered silicas with cagelike pores and three kinds of ordered silicas with cylindrical pores. The lower closure point pressure of nitrogen in the cagelike pores with sufficiently small necks, that is, the cavitation pressure of a confined liquid, did not depend appreciably on the cage size in the temperature region far away from a hysteresis critical temperature (Tch) but its cage-size dependence was noticeable in the vicinity of Tch. The lower closure point in the cylindrical pores depended on the pore size, and its thermal behavior was totally different from that in the cagelike pores. Nevertheless, the hysteresis critical points of nitrogen in the ordered mesoporous silicas, which are defined as a threshold of temperatures (Tch) and pressure above which reversible capillary condensation takes place in a given size and shape of pores, fell on a common line in a temperature-pressure diagram regardless of the pore geometries. We consider this finding as evidence that capillary evaporation in the cylindrical pores follows a cavitation process in the vicinity of Tch in the same way as that in the cagelike pores and also that the low limit of the hysteresis loop that has been long recognized since 1965 is due to the occurrence of a vapor bubble in a stretched metastable liquid confined to the pores with decreasing pressure (cavitation).     

Surfactant-mixing effects on the interfacial tension and the microemulsion formation in water/supercritical CO2 system

The effects of surfactant mixing on interfacial tension and on microemulsion formation were examined for systems of air/water and water/supercritical CO2 (scCO2) interfaces and for water/scCO2 microemulsions. A fluorinated surfactant, sodium bis(1H,1H,2H,2H-heptadecafluorodecyl)-2-sulfosuccinate (8FS(EO)2), was mixed with the three hydrocarbon surfactants, Pluronic L31, Tergitol TMN-6, and decyltrimethylammonium chloride (DeTAC), at equimolar ratio. For all the cases, the interfacial tension was significantly lowered by the mixing. The positive synergistic effect suggests that the mixed surfactants tend to pack more closely on the interface than the pure constituents. It was found, however, that the microemulsion formation in scCO2 was never facilitated by the mixing, except for the case of TMN-6. This is probably due to the segregation of the surfactants into hydrocarbon-rich and fluorocarbon-rich phases on the microemulsion surface.     

Estimation of the Refractive Index Change in Glass Induced by Femtosecond Laser Pulses

It is known that local refractive index change occurs when femtosecond laser pulses with extremely high peak power are launched into glass. We focused 130-femtosecond laser pulses of 800 nm into the bulk of glass and examined the shape of the induced refractive index change. We found that the length of the spot of the refractive index change along the optical axis reached about 30 μm despite the diameter being about 2 μm. To estimate the distribution of induced refractive index change, we fabricated Bragg grating by scanning the focused spot and calculated the amount of the change by applying Kogelnik’s coupled mode theory to the measured diffraction efficiencies of the higher order diffracted beams.     

Anionic Polymerization of New Dual-Functionalized Styrene and α-Methylstyrene Derivatives Having Styrene or α-Methylstyrene Moieties

Anionic polymerizations of four new dual-functionalized styrene and α-methylstyrene derivatives, 3-(4-(4-isopropenylphenoxy)butyl)styrene ( 4 ), 3-(4-(2-isopropenylphenoxy)butyl)-α-methylstyrene ( 5 ), 4-(4-(4-isopropenylphenoxy)butyl)-α-methylstyrene ( 6 ), and 4-(4-(2-vinylphenoxy)butyl)styrene ( 7 ), were carried out in THF at -78 °C with sec-BuLi as an initiator. Both 4 and 5 underwent anionic polymerization in a living manner to quantitatively afford functionalized polystyrenes and poly(α-methylstyrene)s having α-methylstyrene moiety in each monomer unit and precisely controlled chain lengths. On the other hand, insoluble polymers were obtained by the anionic polymerization of 6 and 7 under the same conditions. The positional effect of substituent on anionic polymerization was discussed.     

Anti-Obesity Effects of Matoa (Pometia pinnata) Fruit Peel Powder in High-Fat Diet-Fed Rats

Fruit peels, pericarps, or rinds are rich in phenolic/polyphenolic compounds with antioxidant properties and potentially beneficial effects against obesity and obesity-related non-communicable diseases. This study investigated the anti-obesity effects of matoa (Pometia pinnata) and salak (Salacca zalacca) fruit peel. Neither matoa peel powder (MPP) nor salak peel powder (SPP) affected the body weight, visceral fat weight, or serum glucose or lipid levels of Sprague–Dawley rats when included as 1% (w/w) of a high-fat diet (HFD). However, MPP significantly decreased the hepatic lipid level. MPP at a dose of 3% (w/w) of the HFD decreased body weight, visceral fat, and serum triglyceride levels as well as the hepatic lipid content. The inhibitory effect of MPP on hepatic lipid accumulation was not enhanced when its concentration was increased from 1% to 3% of the HFD. The anti-obesity effect of matoa was partly explained by the inhibitory effect of the matoa peel extract on fatty acid-induced secretion of ApoB-48 protein, a marker of intestinal chylomicrons, in differentiated Caco-2 cell monolayers. We identified hederagenin saponins that are abundant in MPP as potential anti-obesity substances. These results will contribute towards the development of functional foods with anti-obesity effects using the matoa fruit peel.     

Low temperature deposited Zr-B film applicable to extremely thin barrier for copper interconnect

We have prepared thin Zr-B films at low temperatures as a new material applicable to an extremely thin barrier against Cu diffusion in Si-ULSI metallization. The obtained Zr-B films mainly consist of the ZrB₂ phase with a nanocrystalline texture on SiO₂ and a fiber texture on Cu. The resistivity of the Zr-B films depends on the substrate of SiO₂ or Cu. The constituent ratio of B/Zr is almost 2, though the contaminants of oxygen, nitrogen, and carbon are incorporated in the film. The nanocrystalline structure of the Zr-B film on SiO₂ is stable due to annealing at temperatures up to 500 °C for 30 min. We applied the 3-nm thick Zr-B film to a diffusion barrier between Cu and SiO₂, and the stable barrier properties were confirmed. We can demonstrate that the thin Zr-B film is a promising candidate for thin film application to a metallization material in Si-ULSIs.