Number Density of Liquid Inclusions Formed in Frozen Aqueous Electrolyte

Frozen aqueous chlorides (≤50 mM ) are characterized by using confocal fluorescence microscopy and small angel X‐ray scattering (SAXS). The former method allows us to determine the size of a liquid inclusion formed in the ice matrix at temperatures above the eutectic point of the system (t_eu). Isolated liquid inclusions of a uniform size are formed when the temperature of a frozen electrolyte increases past t_eu. The size of the liquid inclusions depends on the observation temperature as well as on the concentration (c_salt) and type of salt dissolved in the original unfrozen solution. However, the number density of liquid inclusions is almost constant and independent of these experimental parameters, particularly when an electrolyte is frozen in liquid nitrogen. Salt accumulation can then occur at the imperfections of the ice crystals. The occurrence probability of the imperfections is independent of the nature of an incorporated salt. The amount of a salt confined in each inclusion ranges from 7 to 240 fmol, depending on c_salt. SAXS measurements provide information on the size of individual salt crystals formed at temperatures below t_eu. The radius of gyration of a salt crystal ranges from 2 to 2.8 nm, and does not depend significantly on c_salt. Thus, each inclusion is formed from 10⁶–10⁹ nanocrystals, which can act as seeds. When doped ice is prepared at higher temperatures, for example ?16 °C, the isolation of liquid inclusions is not sufficient and coalescence occurs more easily upon an increase in temperature or c_salt. However, when c_salt is lower than 10 mM , the number density of liquid inclusions is almost constant, irrespective of the freezing temperature.     

Synthesis of 3-Trifluoromethyl-4-halobenzonitriles

The practical synthetic method for a series of substantially novel fluorine-containing polyfunctional aromatic compounds, 3-trifluoromethyl-4-halobenzonitriles [halo = Cl, Br, and F], was established by using copper-cyano complexes as effective Sandmeyer cyanating reagents.     

Novel heterocyclization of 4-phenylthiosemicarbazones and related compounds with chlorocarbonylsulfenyl chloride

Chlorocarbonylsulfenyl chloride was allowed to react with 1-alkylidene-4-phenylthiosemicarbazones in the presence of triethylamine to give 1,2,4-triazolines, whereas with 1-arylidene-4-phenylthiosemicarbazones to afford 1,2,4-dithiazolidines. Treatment of diarylidenethiocarbohydrazides and diarylidenaminoguanidines with chlorocarbonylsulfenyl chloride under similar conditions gave 1,2,4-dithiazolidines and 1,2,4-thiadiazolidines, respectively.     

Hyperfine coupling constants of NCO in ÃΣ by sub-Doppler spectroscopy

Molecular constants including ¹⁴N hyperfine coupling constants of the NCO radical in the òΣ⁺(000) state have been determined precisely by using the microwave-optical double resonance (MODR) and intermodulated fluorescence (IMF) techniques, where the band was pumped by a dye laser. The results are B = 12 056.559(41), D = 0.0045(16), γ = 22.06(17), b = 430.4(12), c = 80.3(28), and eQq = 2.6(36), all in MHz with one standard error in parentheses. It was found that, because the òΣ⁺ state closely approximates a coupling case (b_βS), MODR did not provide any precise value for the Fermi contact term, but this constant was determined accurately by combining the MODR spectrum with the IMF spectrum.     

Novel technique for connecting waveguides and fibers

A practical technique with low coupling loss has been developed for connecting waveguides and fibers by adjusting and fixing them one by one. A thin strip of glass is permanently cemented on the side of the fiber near the tip to be joined. This strip is used as a manipulator, after which it is cemented to the substrate.     

Synthesis and spectroscopic properties of a series of beta-blocked long oligothiophenes up to the 96-mer: revaluation of effective conjugation length

A series of extraordinarily long oligothiophenes up to the 96-mer has been developed by iterative oxidative coupling of the completely beta-blocked sexithiophene. They are highly conjugated like nonsubstituted oligothiophenes, and the effective conjugation of this system is extended to 96 thiophene units and much longer than that previously speculated for polythiophenes.     

Spontaneous immobilization of liposomes on electron-beam exposed resist surfaces

We have found an interesting immobilization technique of liposomes on electron-beam exposed resist surfaces. The immobilized liposomes have been visualized by the atomic force microscope and have shown well-organized three-dimensional physical structures, in which the liposomes maintain their shapes and sizes similar to those of the original design in prepared solution. The immobilization is based on a strong static charge interaction between the resist surface and the liposomes. Further experiments show that very strong charge in the surfaces produces the firm immobilization of the liposome. We believe these findings can be related to various liposome applications such as drug delivery system, electrochemical or biosensors, and nanoscale membrane function studies.     

Biosynthesis of indole diterpenes, emindole, and paxilline: involvement of a common intermediate

The key step for construction of the carbon skeleton in the indole diterpenes, paxilline, and emindole DA was examined. Intact incorporation of multiply (2)H-labeled 3-geranylgeranylindole into two different fungal metabolites proves 3-geranylgeranylindole to be a biosynthetic intermediate. These results give evidence that indole diterpenes are biosynthesized via epoxidation of a common intermediate, and the subsequent cationic cyclization, analogous to those in the steroid biosynthesis. [structure: see text]