Mitsubishi Paper Mills (Japan)

We now report metal-free organic dyes having a new type of indoline structure, which exhibits high efficiencies in dye-sensitized solar cells. The solar energy to current conversion efficiencies with the new indoline dye was 6.51%. Under the same conditions, the N3 dye was 7.89% and the N719 dye was 8.26%. The new indoline dye was optimized for the amount of 4-tert-butyl pyridine in the electrolyte and cholic acid as a coadsorbent. Subsequently, the solar energy to current conversion efficiencies reached 8.00%. This value was the highest obtained efficiency for dye-sensitized solar cells based on metal-free organic dyes without an antireflection layer.

An indoline dye (D205), the synthesis method of which is disclosed in this report, gave high-efficiency organic dye-sensitized solar cells (9.52%) using an anti-aggregation reagent (chenodeoxycholic acid).

TiO(2) nanotube arrays prepared by electrochemical anodization of Ti foils show impressive light to electricity conversion efficiency in the dye-sensitized solar cells (DSCs). The length of the TiO(2) nanotube arrays (5-14 microm) was controlled by varying the anodization time from 2 to 20 h. The influence of nanotube lengths on the photovoltaic performance of DSCs was investigated by impedance. A flexible DSC using TiO(2) nanotube arrays on a Ti foil as a working electrode and polyethylene naphthalate (ITO/PEN) as counterelectrode in combination with solvent-free ionic liquid electrolyte achieved 3.6% photovoltaic conversion efficiency under simulated AM 1.5 sunlight.

The feasibility of solid-state dye-sensitized solar cells as a low-cost alternative to amorphous silicon cells is demonstrated. Such a cell (see Figure) with a record efficiency of over 4 % under simulated sunlight is reported, made possible by using a new organic metal-free indoline dye (see Figure) as the sensitizer with high absorption coefficient.

A solar-to-electric conversion efficiency of 6.1% is achieved with this new dye, compared to 6.3% for N3 dye under the same experimental conditions. Although these indoline dyes are slightly less efficient than N3 dye, the cost of indoline dye is much less than for N3 due to ease of preparation. Furthermore, indoline dyes are shown to be highly stable to photoredox processes by cyclic voltammogram.

Poly(γ-glutamic acid) (PGA) production in Bacillus subtilis IF03335 was studied. When citric acid as a carbon source was added to a glutamic acid medium containing L-glutamic acid and ammonium sulfate, a large amount of pure PGA was produced. On the other hand, when glucose was added to the glutamic acid medium, a by-product was produced, which seemed to be a polysaccharide. Moreover, the mode of hydrolysis was investigated with PGA in aqueous solutions at 80, 100, and 120°C by monitoring the time-dependent changes in the molecular weights. Hydrolytic degradation of PGA was found to proceed through a random chain scission.

Nanoparticles are attractive nanomaterials, since they exhibit unique physical and chemical properties. We have found that poly(substituted thiophene) nanoparticles, ranging in size from several tens to hundreds of nanometers, exhibit size-dependent characteristic spectroscopic properties and thermochromic behavior, which can be explained by distorted polymer conformations in the surface layer (see graphic).

The introduction of chimeric sense and antisense gene constructs for 4-coumarate:coenzyme A ligase into tobacco plants caused the reduction of the 4CL activity in the transgenic plants. In the transgenic plants, the cell walls of the xylem tissue in stems were brown and the molecular structure of lignin in the colored cell walls was dramatically different from that in the control plants. Analysis with different types of stain revealed that levels of cinnamyl aldehyde residues and syringyl units in lignin were depressed in the brownish cell walls. Furthermore, the lignin content in colored tissue was lower than that in the normal tissue. Our results indicate that 4CL has important roles in the determination of the composition and the amount of lignin in tobacco plants.

Transgenic tobacco (Nicotiana tabacum L.) plants in which the activity of 4-coumarate:coenzyme A ligase is very low contain a novel lignin in their xylem. Details of changes in hydroxycinnamic acids bound to cell walls and in the structure of the novel lignin were identified by base hydrolysis, alkaline nitrobenzene oxidation, pyrolysis-gas chromatography, and 13C-nuclear magnetic resonance analysis. In the brownish tissue of the transgenic plants, the levels of three hydroxycinnamic acids, p-coumaric, ferulic, and sinapic, which were bound to cell walls, were apparently increased as a result of down-regulation of the expression of the gene for 4-coumarate:coenzyme A ligase. Some of these hydroxycinnamic acids were linked to cell walls via ester and ether linkages. The accumulation of hydroxycinnamic acids also induced an increase in the level of condensed units in the novel lignin of the brownish tissue. Our data indicate that the behavior of some of the incorporated hydroxycinnamic acids resembles lignin monomers in the brownish tissue, and their accumulation results in dramatic changes in the biosynthesis of lignin in transgenic plants.

In recent approaches to tissue engineering, cells face various stresses from physical, chemical, and environmental stimuli. For example, coating cell membranes with nanofilms using layer-by-layer (LbL) assembly requires many cycles of centrifugation, causing physical (gravity) stress. Damage to cell membranes can cause the leakage of cytosol molecules or sometimes cell death. Accordingly, we evaluated the effectiveness of LbL films prepared on cell membranes in protecting cells from physical stresses. After two steps of LbL assembly using Tris-HCl buffer solution without polymers or proteins (four centrifugation cycles including washing), hepatocyte carcinoma (HepG2) cells showed extremely high cell death and the viability was ca. 15%. Their viability ultimately decreased to 6% after 9 steps of LbL assembly (18 cycles of centrifugation), which is the typical number of steps involved in preparing LbL nanofilms. However, significantly higher viability (>85%) of HepG2 cells was obtained after nine steps of LbL assembly employing fibronectin (FN)-gelatin (G) or type IV collagen (Col IV)-laminin (LN) solution combinations, which are typical components of an extracellular matrix (ECM), to fabricate 10-nm-thick LbL films. When LbL films of synthetic polymers created via electrostatic interactions were employed instead of the ECM films described above, the viability of the HepG2 cells after the same nine steps slightly decreased to 61%. The protective effects of LbL films were strongly dependent on their thickness, and the critical thickness was >5 nm. Surprisingly, a high viability of over 85% was achieved even under extreme physical stress conditions (10,000 rpm). We evaluated the leakage of lactate dehydrogenase (LDH) during the LbL assembly processes to clarify the protective effect, and a reduction in LDH leakage was clearly observed when using FN-G nanofilms. Moreover, the LbL films do not inhibit cell growth during cell culturing, suggesting that these coated cells can be useful for other experiments. LbL nanofilm coatings, especially ECM nanofilm coatings, will be important techniques for protecting cell membranes from physical stress during tissue engineering.

Organic-based solar cells potentially offer a photovoltaic module with low production costs and low hazard risk of the components. We report organic dye-sensitized solar cells, fabricated with molecular designed indoline dyes in conjunction with highly reactive but robust nitroxide radical molecules as redox mediator in a quasi-solid gel form of the electrolyte. The cells achieve conversion efficiencies of 10.1% at 1 sun, and maintain the output performance even under interior lighting. The indoline dyes, customized by introducing long alkyl chains, specifically interact with the radical mediator to suppress a charge-recombination process at the dye interface. The radical mediator also facilitates the charge-transport with remarkably high electron self-exchange rate even in the quasi-solid state electrolyte to lead to a high fill factor.

The 2D structures of a variety of n-alkyl-substituted perylene diimides adsorbed onto HOPG and MoS2 surfaces from phenyloctane solutions were studied using scanning tunneling microscopy (STM). Both rectangular, or herringbone-like, structures and row structures were observed. Surprisingly, the lattice constants, and thus the area per molecule of the rectangular structures, did not increase as expected when the alkyl chain length was increased. Protrusion of the alkyl tails into the solvent above the 2D layer is proposed to account for this behavior. Row structures, where the alkyl tails lie flat on the substrate surface, were also observed wherein the area per molecule increases as expected for the increase in the length of the alkyl tail. The formation of domains with a particular orientation with respect to the underlying lattice was observed for many of the 2D structures. The alignment of the molecular layers with the substrate could be explained with a point-on-line coincidence model. Formation and filling of missing molecule defects within the oriented domains was observed during continuous scanning of the STM.

In a study of myofibrillar proteins, Chowrashi and Pepe [1982: J. Cell Biol. 94:565-573] reported the isolation of a new, 85-kD Z-band protein that they named amorphin. We report that partial sequences of purified amorphin protein indicate that amorphin is identical to phosphorylase, an enzyme important in the metabolism of glycogen. Anti-amorphin antibodies also reacted with purified chicken and rabbit phosphorylase. To explore the basis for phosphorylase's (amorphin's) localization in the Z-bands of skeletal muscles, we reacted biotinylated alpha-actinin with purified amorphin and with purified phosphorylase and found that alpha-actinin bound to each. Radioimmune assays also indicated that phosphorylase (amorphin) bound to alpha-actinin, and, with lower affinity, to F-actin. Negative staining of actin filaments demonstrated that alpha-actinin mediates the binding of phosphorylase to actin filaments. There are several glycolytic enzymes that bind actin (e.g., aldolase, phosphofructokinase, and pyruvate kinase), but phosphorylase is the first one demonstrated to bind alpha-actinin. Localization of phosphorylase in live cells was assessed by transfecting cultures of quail embryonic myotubes with plasmids expressing phosphorylase fused to Green Fluorescent Protein (GFP). This resulted in targeting of the fusion protein to Z-bands accompanied by a diffuse pattern in the cytoplasm.

The development of a low-permittivity pressboard obtained by blending polymethylpentene fiber with cellulose fiber is described. The permittivity is 3.5, which is lower than that of conventional pressboard. With this pressboard, insulating characteristics of intercoil models were investigated under lightning impulse and AC voltage conditions. It is demonstrated that a spacer fabricated from this pressboard material increases the partial discharge inception and breakdown voltages up to 30% compared with conventional pressboard spacers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Bacterial cellulose (BC) is produced by some strains of Acetobacter. The BC has unique network structure of fine fiber. The BC can be obtained with two typical methods, namely static and agitated culture. We have found some structural differences between these two types of BC. We, therefore, investigated the properties of the BCs for papermaking.When these two types of BCs were added at wet-end, both tensile strength and filler-retention of the handsheets were improved. Especially, the BC from agitated culture had higher effects on filler-retention than that from static one. Thus, the BC may be useful as a wet-end additive for papermaking.

Abstract A structure analysis has been carried out on the nucleus formed in amorphous Ge films at the initial stage of crystallization by means of high resolution electron microscopy. Small crystallites displaying fivefold symmetries were formed in the amorphous matrix with sizes down to about 10 nm. A columnar structure model for the nuclei which consists of five-membered rings, stacking with a common axis, has been proposed and the computer-simulated electron microscope image produced, based on this model, is in good agreement with the observed images. The results suggest the existence of pentagonal structural units in amorphous germanium which play a salient role as preferential nucleation sites at the stage of incipient crystallization.

Three-dimensional (3D) hepatocyte cultures have attracted much attention to obtain high biological functions of hepatocyte for pharmaceutical drug assessment. However, maintaining the high functions for over one month is still a key challenge although many approaches have been reported. In this study, we demonstrate for the first time simple and rapid construction of 3D-hepatocyte constructs by our cell accumulation technique and their high biological functions for one month, without any medium change. The human hepatocyte carcinoma (HepG2) cells were coated with ∼ 7 nm-sized extracellular matrix (ECM) films consisting of fibronectin (FN) and gelatin (G), and then incubated in cell culture insert to construct 3D-tissue constructs for 24 h. The thickness of obtained 3D-HepG2 constructs was easily controlled by altering seeding cell number and the maximum is over 100 μm. When a large volume of culture media was employed, the 3D-constructs showed higher mRNA expression of albumin and some cytochrome P450 (CYP) enzymes as compared to general two-dimensional (2D) culture. Surprisingly, their high cell viabilities (over 80%) and high mRNA expressions were successfully maintained without medium change for at least 27 days. These results demonstrate novel easy and rapid technique to construct 3D-human liver tissue models which can maintain their high functions and viability for 1 month without medium change.

BACKGROUND: Currently, the cryopreservation of embryos and oocytes is essential for assisted reproductive technology (ART) laboratories worldwide. This study aimed to evaluate the efficacy of the Kitasato Vitrification System (KVS) as a vitrification device for the cryopreservation of mouse embryos to determine whether this novel device can be adapted to the field of ART. METHODS: In Experiment 1, blastocysts were vitrified using the KVS. Vitrified blastocysts were warmed and subsequently cultured for 72 h. In Experiment 2, 2-cell-stage embryos were vitrified using the KVS, and vitrified embryos were warmed and subsequently cultured for 96 h. In Experiment 3, we evaluated the in vivo developmental potential of vitrified 2-cell-stage embryos using the KVS, and in Experiment 4, we evaluated the cooling and warming rates for these devices using a numerical simulation. RESULTS: In Experiment 1, there were no significant differences between the survival rates of the KVS and a control device. However, re-expanded (100%) and hatching (91.8%) rates were significantly higher for blastocysts vitrified using the KVS. In Experiment 2, there were no significant differences between the survival rates, or rates of development to the blastocyst stage, of vitrified and fresh embryos. In Experiment 3, after embryo transfer, 41% of the embryos developed into live offspring. In Experiment 4, the cooling and warming rates of the KVS were 683,000 and 612,000 °C/min, respectively, exceeding those of the control device. CONCLUSIONS: Our study clearly demonstrates that the KVS is a novel vitrification device for the cryopreservation of mouse embryos at the blastocyst and 2-cell stage.

Abstract The alignment of a nematic liquid crystal (LC) was changed reversibly by a photochromic reaction of vinyl‐polymer films bearing azobenzene (Az) chromophores. Photoisomerization of Az in the polymer films proceeded slower than in solution systems with an irreversible nature, due to a limited free volume of polymers and the presence of Az aggregates. Photoregulative Az films were obtained by two procedures: (i) spin‐coating followed by baking processes: and (ii) adsorption from a LC/polymer mixture onto a lecithin‐coated glass surface. Perpendicular alignment, which is achieved both in the surface Az and in the LC layer, allows a parallel interaction between them and enables the photoregulation of the LC alignment.

Abstract Semiempirical HAM/3 MO program was used to obtain the theoretical valence X-ray photoelectron spectra (XPS) of the two leuco dyes (2′-anilino-6′-diethylamino-3′-methylspiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one (DEAMAF) and 3,3-bis(4-dimethylaminophenyl)-6-dimethylamino-1(3H)-isobenzofuranone (CVL)) and UV-visible adsorption spectra of the four leuco dyes (DEAMAF, CVL, 2′-chloro-6′-diethylamino-3′-methylspiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one (DEAMCF), and 3′,6′-bis(diethylamino)-spiro[isobenzofuran-1(3H),9′-[9H]xanthene]-3-one (Rhodamine B base). The calculated Al Kα photoelectron spectra were obtained using Gaussian lineshape functions of an approximate linewidth 0.10Ek (Ek = Ek′ − WD), where E′k is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function, polarization energy and other energy effects. On the other hand, the absorption curves were simulated with Gaussian lineshape functions of a constant linewidth of 0.02 eV. The theoretical valence energy levels corresponded well to the spectra of two leuco dyes observed 0—40 eV, while the simulated adsorption spectra were shifted for a good fit with the experimental solution spectra in the range of 250—700 nm.