Fluorescent cyclopentadithiophene derivatives having phenyl-substituted silyl moieties

4,4-Dimethylcyclopenta[2,1-b:3,4-b′]dithiophene derivatives bearing trimethyl-, dimethylphenyl-, diphenylmethyl-, or triphenyl-silyl moieties were synthesized. The introduction of the silyl moieties onto cyclopenta[2,1-b:3,4-b′]dithiophene induced fluorescent emission as well as the bathochromic shift of wavelength at the maximum absorption and fluorescence. It was found that the larger number of phenyl group on silyl moiety resulted in the higher fluorescence quantum yield.     

Ordered nano-structure of a stamped self-organized protein layer on a HOPG surface using a HFB carrier

A groundbreaking method for ordered molecular layer preparation on a solid surface employing the drop-stamp method has been developed by us taking advantage of the characteristics of the HFB molecule as a self-organizer/adsorption carrier. It is a smart method which can be used to prepare a self-organized protein layer on a solid surface without unspecific adsorption or defects. In our previous report, we clarified the self-organizing nature of HFB-tagged protein molecules on a surface of a solution droplet. In this report, a protein layer was prepared on a HOPG surface by using the drop-stamp method with a maltose binding protein (MBP)-tagged HFBII molecule. The structure of the stamped protein layer was investigated using frequency modulation atomic force microscopy (FM-AFM) in a liquid condition. The FM-AFM images show that the drop-stamp method can prepare an ordered protein layer on a solid surface smartly. The drop-stamp method using a HFB carrier is a practical method which can be used to prepare an ordered protein layer on a solid substrate surface without unspecific adsorption defects.     

Study of Interactions Between Eu(thenoyltrifluoroacetonate)<Subscript>3</Subscript> and a Photosynthetic Chlorophyllous Pigment

Eu(thenoyltrifluoroacetonate)₃(Eu(TTA)₃), an ideal model lanthanide complex which harvests ultraviolet light in high yield and emits visible light efficiently, was coordinated with a chlorophyll derivative, methyl pyropheophorbide-a (MPA). A distinct color change, from blue to deep green, in solution gives evidence for a supramolecular interaction within the binary system. Ultraviolet-visible absorption and luminescence excitation/emission spectra, as well as luminescence lifetimes and quantum yield measurements, further show that molecular interactions occur between the two components.     

Differential Effects of Cold Exposure on Gene Expression Profiles in White Versus Brown Adipose Tissue

The thermogenic function of brown adipose tissue (BAT) is known to be markedly elevated when animals are exposed to the cold, and intensive studies have been carried out to understand the molecular basis enabling effective thermogenesis in cold-exposed animals. In this study, we used microarray analysis to examine the effects of cold exposure of animals on their gene expression profiles in white adipose tissue (WAT), which seems to function as a counterpart tissue of BAT. The results indicate that the effects of cold exposure on the gene expression profiles of WAT were much more moderate than the effects on those of BAT. Possible reasons for the different responses of BAT and WAT to cold exposure are discussed.     

Addressable electrode array device with IDA electrodes for high-throughput detection

An electrochemical device is proposed for high-throughput electrochemical detection that consists of 32 row and 32 column electrodes on a single glass substrate. The row and column electrodes are connected to interdigitated array (IDA) electrodes to form 1024 (32 × 32) addressable sensor points in the device. Electrochemical responses from each of the 1024 sensors were successfully acquired on the device within 1 min using redox cycling at individual IDA electrodes, which ensures application of the device to comprehensive, high-throughput electrochemical detection for enzyme-linked immunosorbent assay (ELISA), reporter gene assay for monitoring gene expressions, and DNA analysis.     

Photoemission study on the valence band of a β-FeSi2 thin film using synchrotron radiation

Resonant and constant-initial state photoemission spectroscopies using synchrotron radiation were applied to investigate the valence-band electronic structure of a semi-conducting β-type iron-disilicide (β-FeSi(2)) thin film. The results clearly indicated that the component elements, iron (Fe) and silicon (Si), contribute differently to the valence band features; the Fe 3d orbitals mainly concentrate in the top region of the valence band while the Si 3s and 3p orbitals spread over the wide region of the valence band. The β-FeSi(2) thin film showed a typical p-type semi-conducting nature with a work function of 4.78 eV. The β-FeSi(2) film showed the Fe M(1)VV Auger lines around the kinetic energy of 88 eV. It would be expected from these observations that there exist strong interactions between iron and silicon atoms in the β-FeSi(2) film resulting in orbital mixing and band formation.     

Selective photoinduced energy transfer from a thiophene rotaxane to acceptor

An energy transfer process was investigated using cyclodextrin-oligothiophene rotaxanes (2T-[2]rotaxane). The excited energy of 2T-[2]rotaxane is transferred to the sexithiophene derivative which is included in the cavity of β-CD stoppers of 2T-[2]rotaxane.     

Enhancement of second hyperpolarizabilities in open-shell singlet slipped-stack dimers composed of square planar nickel complexes involving o-semiquinonato type ligands

Using the spin-unrestricted hybrid density functional theory method, we have investigated the intermolecular interaction effects on the longitudinal static second hyperpolarizability (γ) of open-shell singlet slipped-stack dimers composed of singlet diradical square planar nickel complexes involving o-semiquinonato type ligands, Ni(o-C(6)H(4)X(2))(2) (where X = O, NH, S, Se, PH). For comparison, we have also examined the γ values of a closed-shell singlet slipped-stack dimer composed of closed-shell monomers Ni[o-C(6)H(4)S(NH(2))](2). It is found that for interplanar distance ranging between 3.0 and 5.0 ? the slipped-stack dimers with intermediate monomer diradical characters exhibit larger γ values per monomer (γ(dimer)/2) than those with large monomer diradical characters or than the closed-shell dimer. These results extend the domain of validity of the relationship found between γ and the diradical character for individual molecules. It also turns out that the ratio R = (γ(dimer)/2)/γ(monomer) increases upon decreasing the interplanar distance and that this increase is larger for intermediate diradical character than for the other cases. These phenomena have been analyzed by considering the γ density distributions of the dimers, demonstrating a significant field-induced third-order charge transfer between the monomers in the case of intermediate diradical character. The present results indicate that open-shell singlet slipped-stack aggregates composed of monomers with intermediate diradical characters constitute another mean for achieving highly efficient and tunable third-order nonlinear optical materials.