Novel multicellular prokaryote discovered next to an underground stream.

A diversity of prokaryotes currently exhibit multicellularity with different generation mechanisms in a variety of contexts of ecology on Earth. In the present study, we report a new type of multicellular bacterium, HS-3, isolated from an underground stream. HS-3 self-organizes its filamentous cells into a layer-structured colony with the properties of a nematic liquid crystal.

Vinylpyrroles: solid-state structures and aggregation-induced emission properties.

An aggregation-induced emission chromophore, vinylpyrrole, was prepared from a formylpyrrole derivative, Meldrum's acid, and 1,3-dimethylbarbituric acid. The optical properties of the chromophore both in the solution and solid states were investigated by UV-vis and fluorescence spectroscopy. Single crystal X-ray diffraction measurements revealed that the dimethylbarbituric acid adduct formed a J-aggregate in the solid and resulted in higher fluorescence quantum yield compared to the Meldrum's acid adduct.

Observation of Desorption and Direct Electron Transfer Reaction of Cytochrome on Bare ITO Electrode with Electrochemical Slab Optical Waveguide Spectroscopy.

Cyclic voltammograms (CVs) of cytochrome (cytc) on the bare ITO were measured with every 10 times of the continuous the solution exchange (SE) processes at the same time of slab optical waveguide (SOWG) spectral observation, and it was proved that direct electron transfer (DET) reaction functionality of cytc adsorbed on the bare ITO electrode was kept after 100 times SE processes. The existence of three kinds of cytc molecules which were weakly adsorbed, strongly adsorbed and immobilized on the bare ITO electrode below a monolayer coverage was indicated from the change in the Soret band absorbance at 408 nm due to the desorption reaction of cytc with observation by electrochemically controlled SOWG spectroscopy. As the actual procedure, 100 times of the SE process in the SOWG cell by hands induced the gradual decrease of the absorbance due to cytc desorption, and with every 10 times of the SE process SOWG absorption spectra were obtained.

Synthesis, Crystal Structure, and Photoluminescent Properties of 3,3',4,4'-Tetraethyl-5,5'-divinyl-2,2'-bipyrrole Derivatives.

Photoluminescent divinylbipyrroles were synthesized from 3,3',4,4'-tetraetyl-2,2'-bipyrrole-5,5'-dicarboxaldehyde and activated methylene compounds via aldol condensation. For mechanistic clarity, molecular structures of Meldrum's acid- and 1,3-dimethylbarbituric acid-derived divinylbipyrroles were determined by single-crystal X-ray diffraction. Photoluminescent properties of the synthesized divinylbipyrroles in dichloromethane were found to be dependent on the presence of electron withdrawing groups at the vinylic terminal.

Efficient Upconversion by Highly Water-Soluble Cationic Sensitizer and Emitter in Aqueous Solutions with DNA.

Highly water-soluble cationic palladium porphyrin as a sensitizer and 9,10-bis(4-trimethylammoniumphenyl)anthracene as an emitter were newly synthesized. They were shown to be bound and immobilized in DNA double helix assembly from absorption, fluorescence, phosphorescence, and circular dichroism spectra. Upon excitation at 532 nm in deaerated aqueous solutions, they showed weak blue upconversion fluorescence, the efficiency of which increased dramatically in the presence of DNA.

In situ Observation of Desorption Reaction of Cytochrome c from Solid/Liquid Interfaces with Slab Optical Waveguide Spectroscopy.

An automated solution exchange (SE) mechanism has been introduced to slab optical waveguide spectroscopy to estimate the protein immobilizing ability of a slab optical waveguide (SOWG) surface. In each SE process, SOWG spectral change in absorbance at peak position of cytochrome c (cyt.c) Soret band at 409 nm was observed to analyze the desorption ratio of cyt.

Fluorescence properties of pyrene derivative aggregates formed in polymer matrix depending on concentration.

We investigated the fluorescence properties of dye aggregates formed in a poly(vinylalcohol) (PVA) matrix by phase separation. Trimethyl-(2-oxo-2-pyrene-1-yl-ethyl)-ammonium bromide (PyAm) was used as a fluorescent dye molecule. The size of PyAm aggregates in the PVA thin films were increased with increasing dye concentration, which was confirmed by atomic force microscope (AFM) measurements.

Interfacial width in polymer bilayer films prepared by double-spin-coating and flotation methods.

A spin-coating method with the aid of selective solvents has been used to construct multilayer structures for organic devices under the assumption that the solvents do not invade a preformed structure. To confirm the assumption, we examined the interfacial width (lambda(i)) of model polymer bilayers, composed of polystyrene and perdeuterated poly(methyl methacrylate), prepared by spin-coating and flotation methods. Neutron reflectivity measurements revealed that the lambda(i) value was larger for the spin-coating method than for the flotation method.

Relaxation behavior of poly(methyl methacrylate) at a water interface.

The relaxation behavior of poly(methyl methacrylate) (PMMA), spin-coated on a silicon wafer, at the water interface was examined by lateral force microscopy as a function of temperature and scanning rate. Even in water, the lateral force peak which was assigned to the segmental motion of PMMA plasticized by water molecules was clearly observed in the temperature domain. The apparent activation energy for the plasticized alpha(a)-relaxation process was much smaller than those for the original alpha(a)-relaxation processes at the intact surface and in the bulk.

The photophysics of selectively metallated arrays of quinoxaline-fused tetraarylporphyrins.

A comprehensive study of the photophysical interactions occurring in tris-porphyrin and tetrakis-porphyrin arrays and has been undertaken. The arrays consist of porphyrins with quinoxaline units fused at the beta,beta'-pyrrolic faces of the macrocycle. The linkage geometry is such that these arrays resemble the arrangement of chromophores that constitute natural photosynthetic reaction centres (PRCs).

Excited-state relaxation process of free-base and oxovanadium naphthalocyanine in near-infrared region.

Excited-state relaxation process of free-base and oxovanadium naphthalocyanine (H(2)Nc and VONc) in solutions and in polymer films was studied by transient absorption measurements. In polymer films only H-aggregate was observed with H(2)Nc with increasing its weight fraction, whereas VONc formed both H- and J-type aggregates. The transient absorption of singlet excited-state of H(2)Nc and VONc in toluene solution decayed with time constant of 250 +/- 30 and 12 +/- 2 ps, respectively.

Interfacial mobility of polymers on inorganic solids.

The segmental mobility of a typical amorphous polymer, polystyrene, at the interfaces with solid substrates was noninvasively examined by fluorescence lifetime measurements using evanescent wave excitation in conjunction with coarse-grained molecular dynamics simulation. The glass transition temperature (T(g)) was discernibly higher at the interface than in the internal bulk region. Measurements at different incident angles of excitation pulses revealed that T(g) became higher closer to the interface.

Highly sensitive detection of transient absorption in dye-doped ultrathin polymer films by the TiO(2)/K(+) composite optical waveguide method upon pulsed laser excitation.

A composite optical waveguide (OWG) composed of a 10-18nm thick titanium dioxide (TiO(2)) film sputtered on a conventional K(+)-doped optical waveguide was first applied to detect transient absorption of organic dyes in ultrathin polymer films upon excitation with ns laser. The thickness of the TiO(2) film considerably affected the relative sensitivity of the composite OWG. The composite OWG with 10nm thick TiO(2) gave much stronger transient absorption for 30-415nm thick polymer films containing organic dyes than that with 18nm TiO(2).

Time-resolved studies of energy transfer from meso-tetrakis(N-methylpyridinium-4-yl)- porphyrin to 3,3'-diethyl-2,2'-thiatricarbocyanine iodide along deoxyribonucleic acid Chain.

The excitation energy transfer from meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP) to 3,3'-diethyl-2,2'-thiatricarbocyanine iodide (DTTCI) along the deoxyribonucleic acid (DNA) double strand was investigated by the steady-state absorption and fluorescence measurements and time-resolved fluorescence measurements. The steady-state fluorescence spectra showed that the near-infrared fluorescence of DTTCI was strongly enhanced up to 86 times due to the energy transfer from the excited TMPyP molecule in DNA buffer solution. Furthermore, we elucidated the mechanism of fluorescence quenching and enhancement by the direct observation of energy transfer using the time-resolved measurements.

Nonsolvents cause swelling at the interface with poly(methyl methacrylate) films.

Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on a substrate in water, hexane, and methanol, which are "nonsolvents" for dPMMA, were examined along the direction normal to the interface by specular neutron reflectivity (NR). The interfaces of dPMMA with the liquids were diffuse in comparison with the pristine interface with air; the interfacial width with water was thicker than that with hexane. Interestingly, in water, the dPMMA film was composed of a swollen layer and the interior region, which also contained water, in addition to the diffused layer.

Kinetics of photoinduced e to z isomerization of azobenzene in polystyrene films: thickness, molecular weight and temperature effects.

E to Z (trans-->cis) photoisomerization of azobenzene (Az) chromophores tagged to polystyrene (PS) in thin films was studied as functions of thickness, PS molecular weight, and temperature, using the change in absorption at 336 nm arising from the Az E isomer remaining upon ultraviolet light irradiation at 350+/-5 nm. The photoisomerization in solid films exhibited fast and slow modes. The fractional amount of the fast mode (I1) started to increase with decreasing film thickness once the films were thinner than a threshold value.

Variable-temperature independently driven four-tip scanning tunneling microscope.

The authors have developed an ultrahigh vacuum (UHV) variable-temperature four-tip scanning tunneling microscope (STM), operating from room temperature down to 7 K, combined with a scanning electron microscope (SEM). Four STM tips are mechanically and electrically independent and capable of positioning in arbitrary configurations in nanometer precision. An integrated controller system for both of the multitip STM and SEM with a single computer has also been developed, which enables the four tips to operate either for STM imaging independently and for four-point probe (4PP) conductivity measurements cooperatively.

Enhanced lasing properties of dissymmetric Eu(III) complex with bidentate phosphine ligands.

The luminescent and lasing properties of Eu(III) complexes were enhanced by using an dissymmetric Eu(III) complex. The photophysical properties (the emission spectral shapes, the emission lifetimes, the emission quantum yields, and the stimulated emission cross section (SEC)) were found to be dependent on the geometrical structures of Eu(III) complexes. The geometrical structures of Eu(III) complexes were determined by X-ray single crystal analyses.