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Substituting carbon with silicon in organic molecules and materials has long been an attractive way to modify their electronic structure and properties. Silicon-doped graphene-based materials are known to exhibit exotic properties, yet conjugated organic materials with atomically precise Si substitution have remained difficult to prepare. Here we present the on-surface synthesis of one- and two-dimensional covalent organic frameworks whose backbones contain 1,4-disilabenzene (C4Si2) linkers. Silicon atoms were first deposited on a Au(111) surface, forming a AuSixfilm on annealing. The subsequent deposition and annealing of a bromo-substituted polyaromatic hydrocarbon precursor (triphenylene or pyrene) on this surface led to the formation of the C4Si2-bridged networks, which were characterized by a combination of high-resolution scanning tunnelling microscopy and photoelectron spectroscopy supported by density functional theory calculations. Each Si in a hexagonal C4Si2ring was found to be covalently linked to one terminal Br atom. For the linear structure obtained with the pyrene-based precursor, the C4Si2rings were converted into C4Si pentagonal siloles by further annealing.

Dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) is a p-type organic semiconductor that exhibits high charge-carrier mobility and atmospheric stability. Although it has been proposed that the transport mechanism of DNTT is a band transport, the valence band dispersion has not yet been observed experimentally. In this study, we elucidate the valence band structure of DNTT single crystals using angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) along three inequivalent crystallographic directions in the surface Brillouin zone (SBZ). The valence band maximum (VBM) is verified to be positioned at the Γ point, and the ionization energy of a DNTT single crystal is determined to be 5.02 eV at the VBM. The effective mass of hole is derived from the curvature of the experimental valence band at the Γ point in all three directions, where the lowest value of 2.6 (± 0.2)m0is measured along the Γ–Sdirection.

Well-defined monolayers with single-crystalline-like molecular arrangements of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]-thiophene (DNTT) and picene, which are a new class of organic semiconductors with enhanced intermolecular interactions, were fabricated and characterized. Although both molecules initially form a loosely packed monolayer with a flat-lying molecule, they undergo phase transition into a densely packed monolayer with single-crystalline-like molecular arrangements with increasing molecular density. Upon the phase transition of the monolayer, the highest occupied molecular orbital (HOMO) level of these molecules splits into two features, as suggested from both the ultraviolet photoelectron spectroscopy and density functional theory calculations. The splitting of the HOMO level was observed to be similar to that expected for the molecular arrangement in the single crystal. This splitting, which has not been observed in the polycrystalline film, suggests a substantial overlap of the HOMO in the well-ordered monolayers.

The role of proximity contact with magnetic oxides is of particular interest from the expectations of the induced spin polarization and weak interactions at the graphene/magnetic oxide interfaces, which would allow us to achieve efficient spin-polarized injection in graphene-based spintronic devices. A combined approach of topmost-surface-sensitive spectroscopy utilizing spin-polarized metastable He atoms and ab initiocalculations provides us direct evidence for the magnetic proximity effect in the junctions of single-layer graphene and half-metallic manganite La0.7Sr0.3MnO3(LSMO). It is successfully demonstrated that in the graphene/LSMO junctions a sizable spin polarization is induced at the Fermi level of graphene in parallel to the spin polarization direction of LSMO without giving rise to a significant modification in the π band structure.

Thickness and substrate dependence of film growth, morphology, unit-cell structure, and electronic structures was thoroughly investigated for picene, the zigzag connected 5-ring molecule, by employing complementary techniques of in situreal-time X-ray reflectivity/diffraction, in situelectron spectroscopies, and atomic force microscopy. A different kind of thickness dependent structural transition was observed on SiO2and graphite, resulting in a distinct electronic structure. On SiO2picene films with 3D crystalline domains are formed with nearly upright molecular orientation from the initial growth stage. With increasing the film thickness the in-plane dimensions of the unit cell in the initially grown domains become smaller (in other words, more compressed), and, at the same time, crystalline domains with a more relaxed structure are nucleating on top of the compressed domains. In spite of such structural changes, the electronic structure, namely energy position of the highest occupied molecular orbital and threshold ionization potential (IPT), is not significantly altered. On graphite, on the other hand, we found a transition from a 2D (layer) to a 3D (island) growth mode with a variation of the molecular orientation from flat-lying to tilted one. The IPTchanges significantly between the 2D and 3D growth regime in contrast to the SiO2system. The origin of the different IPTs of these picene thin films is discussed. The present results are compared with other planar π-conjugated compounds, in particular pentacene which is a structural isomer of picene and shows electronic properties strongly different from picene thin films.

Potassium (K)-induced structural and electronic modifications in the copper hexadecafluorophthalocyanine (F16CuPc) monolayer were investigated by scanning tunneling microscopy and photoemission spectroscopy. The adsorption of K was found to cause a rearrangement of the molecular ordering in the F16CuPc monolayer, depending on the K concentration. For doping with one to two K atoms per molecule, K adsorbs in the intermolecular region adjacent to the aza-bridging nitrogen, forming new ordered phases. A further increase in K coverage causes the on-top adsorption of K, which in turn disorders the monolayer. The photoemission spectrum of the K-doped phase exhibits a small density of states immediately below the Fermi level. Both the formation of the new states and the K-induced structural ordering or disordering of the molecular layer may be responsible for the reported alteration of the macroscopic electronic conductivity.

Microcapsules of a water-in-oil-in-water (W/O/W) emulsion, which contained a hydrophilic substance, 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSA), in its inner aqueous phase, was prepared by hot-air-drying or freeze-drying the emulsion using a single-droplet-drying method. Pullulan, maltodextrin, or gum arabic was used as a wall material, and the oily phase was tricaprylin, oleic acid, olive oil, or a mixture of tricaprylin and olive oil. An encapsulation efficiency higher than 0.95 was reached except for the microcapsules prepared using gum arabic and oleic acid. The hot-air-dried microcapsules were generally more stable than the freeze-dried microcapsules at 37°C and various relative humidities. The stability was higher for the microcapsules with tricaprylin as the oily phase than for the microcapsules with oleic acid. The higher stability of the microcapsules with tricaprylin would be ascribed to the lower partition coefficient of PTSA to the oily phase. There was a tendency for the stability to be higher at lower relative humidity for both the hot-air- and freeze-dried microcapsules. The volumetric fraction of olive oil in its mixture with tricaprylin did not significantly affect either the encapsulation efficiency or the stability of the hot-air-dried microcapsules.

Stereoselective oxidation of (S)-isomer of rac-1-phenylethanol (1-PA) by the yeast Pachysolen tannophilusIFO 1007 immobilized into calcium-alginate gels was investigated to produce (R)-isomer. Continuous production of (R)-isomer was accomplished for more than 80 h with an enantiomeric excess of > 90% using a bioreactor of a fluidized-bed type.

As p53-binding protein 1 (53BP1) localizes to the sites of DNA double-strand breaks and rapidly forms nuclear foci (NF), and its presence may be an indicator of endogenous genomic instability (GIN). We previously showed that 53BP1 NF in cervical cells increase with neoplastic progression, indicating the significance of 53BP1 expression for the estimation of malignant potential during cervical carcinogenesis. This study aimed to further elucidate the impact of 53BP1 expression as a biomarker for cervical squamous intraepithelial lesion (SIL). A total of 81 tissue samples, including 17 of normal cervical epithelium, 22 of cervical intraepithelial neoplasia (CIN) 1, 21 of CIN2, and 21 of CIN3, from patients positive for high-risk human papillomavirus (HR-HPV) were used for double-label immunofluorescence of 53BP1 and Ki-67/p16INK4aexpression and HR-HPV in situ hybridization. We analyzed associations between 53BP1 expression type with parameters such as CIN grade, HR-HPV infection status, p16INK4aexpression, and CIN prognosis. Expression type of 53BP1 was significantly associated with histological grade of CIN and HR-HPV in situ hybridization signal pattern (P< .0001). There was a significant correlation between 53BP1 and p16INK4aexpression levels (r= .73, P< .0001). However, there was no association between 53BP1 expression type and CIN prognosis. We propose that 53BP1 expression type is a valuable biomarker for SIL, which can help estimate the grade and GIN of cervical lesions reflecting replication stress caused by the integration of HR-HPV to the host genome.