On the effects of substitution, intercalation, non-stoichiometry and block layer concept in TiS2 based thermoelectrics.

TiS2 based layered sulfides have recently received increasing interest from the thermoelectric community. Due to its layered structure, the TiS2 compound with its enormous capacity for chemical substitution and intercalation offers different means to optimize the thermoelectric response through concomitant tuning of carrier concentration and decrease of the lattice thermal conductivity. In this review, we first discuss and summarize the crystal structures and physical/chemical properties of TiS2 based layered sulfides. Then, the approaches that successfully enhanced the thermoelectric performances in the TiS2 ceramic samples densified by Spark Plasma sintering are outlined, which include intercalation, non-stoichiometry, cationic substitution, and the block layer concept.

Thick transparent rutile TiO2 films crystallized in solution.

We report a novel process for the preparation of dense, transparent TiO2 films of 2.5 mum thickness on a F-doped SnO2-covered glass substrate. The starting solution contained peroxotitanate complex ions, which are relatively stable under the experimental conditions, permitting the deposition of highly textured rutile nanocrystalline films. The nanocrystals exhibit specific orientations along the (101) and (002) crystalline planes. Kinetic studies suggest that the precipitation started from the formation of amorphous solids, followed by crystallization through a dissolution-recrystallization process. Although a minor phase of anatase was detected only for powders collected from solutions after film preparation, not for films, the transformation from amorphous to anatase was believed to occur before further transformation of anatase to rutile. The present method enables film synthesis on a surface with a large area, and therefore could be integrated into the processing of electroluminescent devices.

Flexible solar-cell from zinc oxide nanocrystalline sheets self-assembled by an in-situ electrodeposition process.

Zinc oxide nanocrystalline sheets were self-assembled on a flexible polymer substrate to act as the electrode of dye-sensitized solar cells by an in situ-construction electrodeposition process. It was discovered that the nanosheet-based solar cell exhibited better performance than a nanoparticle-based solar cell or a well-oriented nanowire-based solar cell. The nanosheet microstructure has advantages which include the depression of loss during photoelectron transport, the increase of dye compound adsorption, and the enhance of incident light capture. As a result, the performance of dye-sensitized solar cells can be obviously improved. This success provides a feasible bottom-up approach for integrating a solar cell together with nanodevices and microcircuits on a flexible substrate which can work with self-supplied solar energy.

Surface precipitation of highly porous hydrotalcite-like film on Al from a zinc aqueous solution.

A hydrotalcite-like film has been successfully deposited on an Al-bearing glass substrate based on an interface reaction between an Al layer and a zinc aqueous solution. The film selectively grew on the Al surface but not on the glass surface. The film on Al was composed of layered nanosheets of a hydrotalcite-like compound containing Al and Zn. Comparably, deposits on the plastic surface and precipitates in solution were wurzite-type ZnO with various morphologies depending upon the preparation conditions. At low supersaturation degrees, single crystals and superstructures of Zn-Al hydrotalcite were also obtained. This porous hydrotalcite film has a potential application as catalyst supports, environmental materials, or matrixes for hydrotalcite-based nanocomposite films. Using Al as a reaction interface makes it easy to coat porous hydrotalcites on a series of matrix materials varying in shapes and properties, which is important for achieving practical applications. In addition, the method developed should be widely applicable to other systems for the preparation of porous or oriented hydrotalcite-like thin films by an appropriate combination of divalent/trivalent solution-substrate systems.

Micropatterning of Ni particles on a BaTiO3 green sheet using a self-assembled monolayer.

We studied surface modification of ceramic BaTiO(3) green sheets including polyvinylbutyral (PVB) as an organic binder and successfully fabricated a patterned self-assembled monolayer (SAM) which has a region of amino groups and a region of silanol groups on the green sheet. The patterned SAM was then immersed in water containing Ni particles that show negative zeta potential in water. Ni particles were attracted to the amino groups of the patterned SAM that show positive zeta potential by attractive electrostatic interaction. Consequently, a micropattern of Ni particles was achieved using a SAM at room temperature in water. This process can be used to fabricate a thin uniform internal Ni electrode for miniaturized high-performance multilayer ceramic capacitors (MLCC).

Nucleation and growth of hydroxyapatite on an amino organosilane overlayer.

An amino organosilane overlayer (NH(2)-overlayer) was successfully processed on Si/SiO(2) substrates. Remarkable nucleation and growth of hydroxyapatite were found to take place on an NH(2)-overlayer after Si/SiO(2) substrates covered with the NH(2)-overlayer were soaked in supersaturated solutions with respect to Ca(2+) and PO(4)(3-) ions [1.0SBF (simulated body fluid), which contains similar compositions to that in a living body and 1.5SBF in which only Ca(2+) and PO(4)(3-) concentrations are 1.5 times than that in 1.0SBF]. The experimental results demonstrated that HAp nucleation on an NH(2)-overlayer is related to the electrostatic attractive force between positive NH(2)-overlayer surface and negative incipient HAp microparticles homogeneously nucleated in 1.5SBF solution at 50 degrees C. On the contrary, fewer HAp particles were observed on negatively charged "OH" terminated self-assembled monolayer (SAM) because of the repulsive interaction. The Ca/P molar ratios of HAp particles increased from 0.92 at the beginning of nucleation in 1.5SBF to 1.63 in 14 days after growth in 1.0SBF at 37 degrees C. After 14 days of soaking in 1.0SBF, a dense HAp film with the thickness up to 8.6 microm was formed on the NH(2)-overlayer.

Polysaccharide-polynucleotide complexes (IV): antihydrolysis effect of the schizophyllan/poly(C) complex and the complex dissociation induced by amines.

Polymer complexes formed by schizophyllan and poly(C) showed a unique antihydrolysis effect when poly(C) was subjected to hydrolysis under basic conditions. The complexation reduced the hydrolysis rate to 80% of the control (i.e., poly(C) itself). However, when we added oligoamines with the intention of catalyzing the hydrolysis, the oligoamines induced dissociation of the complex instead of acceleration of the hydrolysis.

Chemical modification of schizophyllan by introduction of a cationic charge into the side chain which enhances the thermal stability of schizophyllan-poly(C) complexes.

Combining oxidation with periodate and reductive amination, the amino group is introduced only in the side chain of schizophyllan and the product can bind to poly(C) with a higher dissociation temperature than that of the unmodified schizophyllan and poly(C) complex.

Application of schizophyllan as a novel gene carrier.

Schizophyllan (SPG) is a kind of beta-1,3-glucan which has glucose side chain through a beta-1,6-glycosil bond (Fig. 1). It was found that SPG could form complex with single stranded polynucleotides. SPG forms triple stranded complex with single stranded RNAs thorough hydrogen bonding and hydrophobic interaction. It was found tht polynucleotide was protected from nuclease attacking to form the complex with SPG, and SPG enhanced antisense efficient.

A novel technique to specifically separate RNAs by Schizophyllan.

Schizophyllan (SPG) is a kind of beta-1,3-glucan which has glucose side chain through a beta-1,6-glycosil bond (Fig. 1). It was found that SPG could form complex with single stranded polynucleotides. SPG complexes with single stranded RNAs that have similar helix parameter to triple stranded SPG thorough hydrogen bonding and hydrophobic interaction. We prepared single stranded SPG appended gel supports. It worked as affinity column for polynucleotides. Poly(C) and poly(A) was retained in the SPG column at low temperature, though poly(G) passed by SPG column without interaction. RNAs trapped in the SPG appended column were released by changing elution buffer under mild condition. This SPG column could use to separation of mRNA which has poly(A) tail. The results obtained led to the conclusion that SPG which has neither cation charge or nucleic base can play as RNA separation material.

[Effects of morphine, buprenorphine and butorphanol on airway dynamics of the rabbit].

An investigation was made on the effects of morphine, buprenorphine, and butorphanol on airway dynamics with special reference to the airway smooth muscle in rabbits. After tracheostomy under anesthesia, the animals were ventilated with a Servo 900B ventilator, and airway resistance (R) and total compliance (C) were measured according to the method of Norlander, and the effect of each drug was examined. Intravenous injection of morphine 0.2 mg.kg-1 increased R significantly at 10 and 20 minutes after its administration in nontreated animals and changed R insignificantly in animals pretreated with intravenous administration of chlorpheniramine 2.5 mg, an antihistaminic. It is considered that the increase in R after the administration of morphine in the nontreated animals is due to histamine release. Buprenorphine 0.8 micrograms.kg-1 and butorphanol 0.1 mg.kg-1 brought no significant changes in R in both nontreated and the chlorpheniramine pretreated animals. C decreased in all the groups including the control group which received mechanical ventilation alone without any drug administration.