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As a new eco-friendly thermoelectric material, copper tin sulfide (Cu 2 SnS 3 ) ceramics were experimentally studied by Zn-doping. Excellent electrical transport properties were obtained by virtue of 3-dimensionally conductive network for holes, which are less affected by the coexistence of cubic and tetragonal phases that formed upon Zn subsitition for Sn; a highest power factors ~0.84 mW m -1 K -2 at 723 K was achieved in the 20% doped sample. Moreover, an ultralow lattice thermal conductivity close to theoretical minimum was observed in these samples, which could be related to the disordering of atoms in the coexisting cubic and tetragonal phases and the interfaces. Thanks to the phonon-glass-electron-crystal features, a maximum ZT ~ 0.58 was obtained at 723 K, which stands among the tops for sulfide thermoelectrics at the same temperature.

The dielectric constant is a key parameter that determines both optical and electronic properties of materials. It is desirable to tune electronic properties though dielectric engineering approach. Here, we present a systematic approach to tune carrier mobilities of hybrid inorganic/organic materials where layered two-dimensional transition-metal dichalcogenide TiS2 is electrochemically intercalated with polar organic molecules. By manipulating the dielectric mismatch using polar organic molecules with different dielectric constants, ranging from 10 to 41, the electron mobility of the TiS2 layers was changed three times due to the dielectric screening of the Coulomb-impurity scattering processes. Both the overall thermal conductivity and the lattice thermal conductivity were also found to decrease with an increasing dielectric mismatch. The enhanced electrical mobility along with the decreased thermal conductivity together gave rise to a significantly improved thermoelectric figure of merit of the hybrid inorganic/organic materials at room temperature, which might find applications in wearable electronics.

Using synthetic sulfobetaine library, the enzyme activation behavior has been investigated. Comparison of enzyme activation behavior revealed that sulfobetaines equally facilitate enzyme reactions, being consistent with that of carboxybetaines. The subsequent kinetic and solution property analyses clarified that both the kinetic parameter and hydration property changes are identical with those of carboxybetaines, indicating that the difference in the anionic functional group of the betaine structure scarcely affects the enzyme activation. On the other hand, comparison of carboxy- or sulfo-betaines with tetraalkylammonium salts, whose counteranion binds to the ammonium cation intermolecularly, revealed that the activation ability for enzymes of tetraalkylammonium salts is considerably smaller than that of carboxy- or sulfo-betaines. These findings give us a hint to design the useful betaine-type enzyme activators.

The design and synthesis of materials capable of activating the immune system in a safe manner is of great interest in immunology and related fields. Lactobacilli activate the innate immune system of a host when acting as probiotics. Here, we constructed lactobacilli-mimicking materials in which polysaccharide-peptidoglycan complexes (PS-PGs) derived from lactobacilli were covalently conjugated to the surfaces of polymeric microparticles with a wide variety of sizes, ranging from 200 nm to 3 μm. The artificial lactobacilli successfully stimulated macrophages without cytotoxicity. Importantly, we found that the size of artificial lactobacilli strongly influenced their immunostimulating activities, and that artificial lactobacilli of 1 μm exhibited 10-fold higher activity than natural lactobacilli. One major advantage of the artificial lactobacilli is facile control of size, which cannot be changed in natural lactobacilli. These findings provide new insights into the design of materials for immunology as well as the molecular biology of lactobacillus.

Objective: To evaluate an analog library of betaine-type cellular metabolites, which are naturally found in polar fish for survival in subzero temperatures, for preventing denaturation of enzymes during freezing., Results: Comparison of the cryoprotective ability of reported cryoprotectants, such as dimethylsulfoxide, glycerol, ectoine, hydroxyectoine, and trehalose, with betaine-type analogs using α-glucosidase revealed that analogs introducing C3-C6 alkyl chains into an ammonium cation retained 20 % higher activity than the control cryoprotectants at the same concentration. In particular, the analog possessing triplicate n-butyl chains showed a profound effect. It allowed retention of enzyme activity to 95 % even after 100 freeze-thaw cycles, while addition of the control cryoprotectants decreased the activity to 10-20 %. The cryoprotective ability of betaine-type analogs can be applied not only to α-glucosidase but also other enzymes such as β-glucosidase, alkaline phosphatase, lactose dehydrogenase, sulfatase, and horseradish peroxidase., Conclusion: Synthetic betaine-type metabolite analogs possess practicable cryoprotective ability for various enzymes, and are considerably superior to previously reported cryoprotectants.

Organic semiconductors are attracting increasing interest as flexible thermoelectric materials owing to material abundance, easy processing and low thermal conductivity. Although progress in p-type polymers and composites has been reported, their n-type counterpart has fallen behind owing to difficulties in n-type doping of organic semiconductors. Here, we present an approach to synthesize n-type flexible thermoelectric materials through a facile electrochemical intercalation method, fabricating a hybrid superlattice of alternating inorganic TiS2 monolayers and organic cations. Electrons were externally injected into the inorganic layers and then stabilized by organic cations, providing n-type carriers for current and energy transport. An electrical conductivity of 790 S cm(-1) and a power factor of 0.45 mW m(-1) K(-2) were obtained for a hybrid superlattice of TiS2/[(hexylammonium)x(H2O)y(DMSO)z], with an in-plane lattice thermal conductivity of 0.12 ± 0.03 W m(-1) K(-1), which is two orders of magnitude smaller than the thermal conductivities of the single-layer and bulk TiS2. High power factor and low thermal conductivity contributed to a thermoelectric figure of merit, ZT, of 0.28 at 373 K, which might find application in wearable electronics.

A systematic study of La-based perovskite-type oxides from the viewpoint of their electronic conduction properties was performed. LaCo 0.5 Ni 0.5 O 3± δ was found to be a promising candidate as a replacement for standard metals used in oxide electrodes and wiring that are operated at temperatures up to 1173 K in air because of its high electrical conductivity and stability at high temperatures. LaCo 0.5 Ni 0.5 O 3± δ exhibits a high conductivity of 1.9 × 10 3 S cm -1 at room temperature (R.T.) because of a high carrier concentration n of 2.2 × 10 22 cm -3 and a small effective mass m ∗ of 0.10 m e . Notably, LaCo 0.5 Ni 0.5 O 3± δ exhibits this high electrical conductivity from R.T. to 1173 K, and little change in the oxygen content occurs under these conditions. LaCo 0.5 Ni 0.5 O 3± δ is the most suitable for the fabrication of oxide electrodes and wiring, though La 1- x Sr x CoO 3± δ and La 1- x Sr x MnO 3± δ also exhibit high electronic conductivity at R.T., with maximum electrical conductivities of 4.4 × 10 3 S cm -1 for La 0.5 Sr 0.5 CoO 3± δ and 1.5 × 10 3 S cm -1 for La 0.6 Sr 0.4 MnO 3± δ because oxygen release occurs in La 1- x Sr x CoO 3± δ as elevating temperature and the electrical conductivity of La 0.6 Sr 0.4 MnO 3± δ slightly decreases at temperatures above 400 K.

Objective: The aim of this study was to evaluate psychological distress in patients on chronic hemodialysis., Subjects and Methods: A total of 72 patients on chronic hemodialysis were enrolled in this study. We evaluated psychological distress by using the K6 questionnaire, health-related quality of life (HRQOL) by using the EQ-5D questionnaire, and clinical parameters. Among the 72 patients, we also evaluated changes in K6 scores in 58 patients at 1-year follow-up., Results: The mean K6 score was 3.7 ± 3.7 and 2 subjects (2.8%) were defined as having psychological distress. K6 scores were significantly correlated with body fat percentage, albumin level, and EQ-5D scores in total subjects. K6 scores were also significantly and negatively correlated with EQ-5D scores in men and women. In the 1-year follow-up group, changes in K6 scores were weakly and negatively correlated with changes in EQ-5D scores., Conclusion: Psychological distress was closely associated with HRQOL in patients on chronic hemodialysis. Coping strategies for psychological distress might be useful in improving HRQOL in patients on hemodialysis.

The design and synthesis of biomaterials capable of activating the immune system are of interest in immunology-related fields because of their ability to tune up the immune defenses of the host. Lactobacilli are a major constituent of normal human indigenous flora, and some specific strains are known to activate the immune system of the host as probiotics. In this study, we first fabricated novel biohybrid materials in which lactobacilli (L. casei strain Shirota, LcS)-originated polysaccharide-peptidoglycan complexes (PS-PGs) are conjugated with polymeric microparticles (MPs). PS-PGs conjugated onto polymeric MPs surfaces bound its specific antibody, suggesting that PS-PGs kept their original molecular recognition ability. The PS-PGs-based hybrid MPs with an appropriate density of conjugated PS-PGs effectively induced high levels of IL-12 production from macrophages without cytotoxicity. These results suggest that LcS-originated PS-PGs could be available bio-originated materials for developing novel biomaterials capable of activating the immune system in a safe manner.

Objective: The aim of this study was to investigate the relationship between physical activity and health-related quality of life (HRQOL) in patients on chronic hemodialysis., Methods: A total of 31 men (69.0 ± 11.1 years) and 17 women (66.9 ± 10.0 years) among 61 male and 30 female patients on chronic hemodialysis at Innoshima General Hospital, Onomichi, Japan, were enrolled in this cross-sectional study. Physical activity was evaluated using tri-axial accelerometers. HRQOL and psychological distress were also evaluated using the EuroQol questionnaire (EQ-5D) and the K6 questionnaire, respectively., Results: Physical activity evaluated by Σ[metabolic equivalents × h per week (METs·h/w)] was 8.1 ± 6.0 METs·h/w, and EQ-5D score was 0.754 ± 0.177. Among all patients, EQ-5D scores were significantly correlated with physical activity over 4 METs on non-hemodialysis treatment days (r = 0.426, p = 0.003). In women, EQ-5D scores were also correlated with physical activity over 4 METs on hemodialysis treatment days and non-hemodialysis treatment days. By stepwise multiple regression analysis, physical activity over 4 METs on non-hemodialysis treatment days was a determinant factor of EQ-5D even after adjusting for age and K6 scores., Conclusion: Physical activity over 4 METs on non-hemodialysis treatment days might be associated with EQ-5D in patients on chronic hemodialysis, especially in women.

Authors reported an effective path to increase the electrical conductivity while to decrease the thermal conductivity, and thus to enhance the ZT value by nano-inclusions. By this method, the ZT value of Nb-doped SrTiO3 was enhanced 9-fold by yttria stabilized zirconia (YSZ) nano-inclusions. YSZ inclusions, located inside grain and in triple junction, can reduce the thermal conductivity by effective interface phonon scattering, enhance the electrical conductivity by promoting the abnormal grain growth, and thus lead to the obvious enhancement of ZT value, which strongly suggests that, it is possible to not only reduce the thermal conductivity, but also increase the electrical conductivity by nano-inclusions with low thermal conductivity. This study will give some useful enlightenment to the preparation of high-performance oxide thermoelectric materials.

Self-assembled particulate films with a uniform structure over a large area were prepared from La-SrTiO3 nanocubes for thermoelectric applications. UV irradiation was used to assist the formation of particulate film for decomposition of the organic phase in situ to obtain a mechanically robust structure at high temperature. The thermoelectric properties of the particulate film were measured after calcination at 1000 °C under a reductive atmosphere (Ar/H2 = 60/40). A Seebeck coefficient of S = -239 ± 24 μV/K, electrical conductivity of σ = 160 ± 5 S/cm, and thermal conductivity of κ ≈ 1.5 W/mK were obtained for a self-assembled particulate film (La: 5%) corresponding to a ZT value of 0.2 at room temperature, which exceeded that of a La-SrTiO3 single crystal with similar composition.

We investigated the thermoelectric properties of titanium sulphene, namely, few-layered TiS(2) nanosheets, by using density functional theory and the Boltzmann transport equations. The Seebeck coefficient of titanium sulphene was found to increase if the thickness fell below 14 triple layers (~8 nm) and for the monolayer becomes 40% larger than that of the bulk TiS(2). This behavior is attributed to an enhancement in the density of states near the conduction band minimum in the monolayer. Moreover, the acoustic phonon band of the monolayer is more flat than that of the bulk, which results in a 37% reduction of the acoustic phonon group velocity and was beneficial for a low lattice thermal conductivity. Therefore, the combined effects from quantum confinement of both electrons and phonons could lead to a significant enhancement in thermoelectric performance in the two-dimensional titanium sulphene.

To determine the applicability of LaCo(1-x)Ni(x)O(3) in a conductive material for electrical wiring, the dependence of the electronic transport property on the Ni content is investigated via Hall effect measurements, Rietveld analyses, and band-structure calculations. Ni doping (50 mol %) into the Co sites realizes a high electrical conductivity of 1.9 × 10(3) S/cm, which is an unexpectedly high value for a LaCo(1-x)Ni(x)O(3) system, at room temperature due to the high carrier concentration of 2.2 × 10(22) cm(-3) and the small effective mass of 0.1 m(e). In addition, the high electrical conductivity is maintained from room temperature to 900 °C; that is, the temperature coefficient of the conductivity is smaller than that of standard metals. Thus, the results indicate that LaCo(0.5)Ni(0.5)O(3) is suitable as a conductive material for electrical wiring at high temperatures in air.

A self-assembled-monolayers (SAMs) modified anodic aluminum oxide (AAO) membranes were used to generate crystalline strontium titanate (SrTiO3) nanotube arrays, which have been characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), coupled with electron diffraction analysis. The possible formation mechanism can be explained by the induced nucleation effect of the functional headgroups in the SAMs.

SrTiO3 nanoplates are obtained by the precipitation of an aqueous gel suspension. The gel suspension is prepared by hydrolysis of a Titanium isopropoxide [Ti(OCH(CH3)2)4] solution with NaOH and the addition of Sr(NO3)2. The amount of additive oleic acid plays a significant role in the formation of pure SrTiO3 phase with specific morphologies. The results of transmission electron microscopy (TEM) and electron diffraction (ED) investigations provide evidences that the oriented aggregation of small nanocubes is the dominant growth mechanism for the formation of the observed SrTiO3 nanoplates. The primary nanocrystals are self-assembled in a highly oriented fashion, producing defective single-crystal particles. The above results show that the directional aggregation process can be controlled by changing the temperature of the suspension as well as by adding organic molecules, by which the SrTiO3 particles can be obtained with a controlled size and shape.

Magnetoresponsive hybrid capsules formed with polyelectrolytes, amphiphile bilayers and Fe(3)O(4) nanoparticles were fabricated by a colloid-templating technique. Melamine-formaldehyde (MF) core particles with polyelectrolyte multilayer shell were prepared by layer-by-layer assembly. Fe(3)O(4) nanoparticles were additionally deposited on the capsular surface. Hollow capsules were obtained by the removal of the MF core particles. Amphiphile bilayer was finally coated on the obtained hollow capsules. The deposition amount of the Fe(3)O(4) nanoparticles is variable by changing the concentration of Fe(3)O(4) dispersion using for preparation of capsules. Encapsulated dyes were released on-demand by irradiation with an alternating magnetic field, due to a phase transition in the amphiphile membrane, induced by heating of the magnetic nanoparticles. The release rate of the hybrid capsules was controllable through controlling the deposition amount of Fe(3)O(4) nanoparticles on the capsules., (Copyright © 2011 Elsevier Inc. All rights reserved.)

A new approach to control the release of encapsulated materials from liposomes by using thermosensitive block copolymers and magnetic nanoparticles is reported. Hydrophobized Fe(3) O(4) nanoparticles are synthesized via the hydrothermal process, and can be incorporated into liposomal membranes by hydrophobic interactions. Thermosensitive block copolymers of (2-ethoxy)ethoxyethyl vinyl ether (EOEOVE) and octadecyl vinyl ether (ODVE) are synthesized by living cationic polymerization. The poly(EOEOVE) block acts as a temperature-sensitive moiety, and the poly(ODVE) block acts as an anchor unit. Hybrid liposomes encapsulating pyranine, a water-soluble fluorescent dye, are prepared from mixtures of phospholipids, the hydrophobized Fe(3) O(4) nanoparticles, and the copolymer. While the hybrid liposomes released negligible amounts of pyranine under static conditions, the release of pyranine is drastically enhanced by alternating magnetic field irradiation. The magnetically induced release is attributed to the transition of the thermosensitive segment of the copolymer, which is caused by the release of localized heat from the Fe(3) O(4) nanoparticles under magnetic stimuli, rather than the rupture of the capsules. The release rate of the hybrid capsules is controlled by varying the amount of Fe(3) O(4) nanoparticles embedded into the liposomes., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We investigated the structural effects of metabolite analogs derived from a naturally-occurring zwitterionic metabolite, glycine betaine, on the activity of several hydrolases. The initial velocities of the hydrolases were enhanced by the addition of the solutes into the buffer solution. Based on a detailed study using α-glucosidases, the acceleration efficiency of the enzymatic activity was strongly induced by solutes possessing bulky and aliphatic ammonium cations, indicating that enhancement of activity by the solutes depended on their chemical structures. Kinetic analysis revealed that the acceleration of the hydrolysis reaction was related to both the decrement of K(m) and increment of V(max) values. Furthermore, the addition of the metabolite analogs enhanced not only the rate constant but also the thermostability, salt tolerance, and substrate specificity of α-glucosidase simultaneously through the reduction of conformational perturbation of the enzyme., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Strontium titanate (SrTiO(3)) nanoparticles with well defined cubic shape and sub-10 nm size that are highly dispersible in non-polar organic solvents were successfully synthesized by hydrothermal (HT) processing. Water-soluble titanium complexes and strontium hydroxide were employed as precursors. When the HT process was carried out without oleic acid, the SrTiO(3) particles obtained were relatively large and aggregated. However, SrTiO(3) nanocubes that are highly dispersible in hexane were obtained via the HT process using oleic acid and hydrazine.

Thermal conductivity is one of the key parameters in the figure of merit of thermoelectric materials. Over the past decade, most progress in thermoelectric materials has been made by reducing their thermal conductivity while preserving their electrical properties. The phonon scattering mechanisms involved in these strategies are reviewed here and divided into three groups, including (i) disorder or distortion of unit cells, (ii) resonant scattering by localized rattling atoms and (iii) interface scattering. In addition, we propose construction of a 'natural superlattice' in thermoelectric materials by intercalating an MX layer into the van der Waals gap of a layered TX 2 structure which has a general formula of ( MX ) 1+ x ( TX 2 ) n ( M =Pb, Bi, Sn, Sb or a rare earth element; T =Ti, V, Cr, Nb or Ta; X =S or Se and n =1, 2, 3). We demonstrate that one of the intercalation compounds (SnS) 1.2 (TiS 2 ) 2 has better thermoelectric properties compared with pure TiS 2 in the direction parallel to the layers, as the electron mobility is maintained while the phonon transport is significantly suppressed owing to the reduction in the transverse phonon velocities.

Magnetoresponsive smart capsules formed with polyelectrolytes, lipid bilayers and magnetic nanoparticles were fabricated by a colloid-templating technique. Melamine-formaldehyde core particles with polyelectrolyte multilayer shell were prepared by layer-by-layer assembly. Magnetite (Fe(3)O(4)) nanoparticles were selectively deposited on the capsular surface by aqueous solution deposition using Pd catalysts. Hollow capsules were obtained by the removal of the melamine formaldehyde core particles. Vibrating sample magnetometer (VSM) measurement of the capsules revealed the ferromagnetic behavior of deposited Fe(3)O(4) nanoparticles. Alternating magnetic field irradiation generates heat in the capsular dispersion. Additional lipid bilayer coating was carried out on the obtained hollow capsules. Dye molecules were loaded by exploiting the temperature-dependence of the lipid membrane permeability. An encapsulated dye was released on-demand by irradiation with an alternating magnetic field, due to a phase transition in the lipid membrane, induced by heating of the magnetic nanoparticles. The magnetically induced release is attributed to the phase transition of the lipid membrane, caused by heat of Fe(3)O(4) nanoparticles under magnetic stimuli, and not to rupture of the capsules.

Well-defined magnetic hybrid hollow capsules formed with magnetite (Fe(3)O(4)) and polyelectrolyte-multilayer films were successfully prepared through colloidal templating with layer-by-layer assembly of polyelectrolytes, followed by aqueous solution deposition of Fe(3)O(4). Pd catalyst nanoparticles played an important role in the deposition of Fe(3)O(4). Pd nanoparticles favorably adsorbed onto the polyelectrolyte layer with positively charged amino groups. Hollow capsules were obtained by the removal of the melamine-formaldehyde core particles. Although the processes were performed in aqueous solutions at temperatures less than 60 degrees C, X-ray diffraction patterns revealed that the deposited Fe(3)O(4) was highly crystallized. The hollow capsules were stably dispersed in water; however, the capsules rapidly congregated around a locally applied magnet.

We have designed and synthesized a novel photo-responsive linker unit, 4,4'-bis(hydroxymethyl)-azobenzene, which was introduced to the loop oligonucleotide in a DNA hairpin and was able to reversibly control the stability of the whole hairpin structure via UV or visible light irradiation.

We developed an aqueous solution system to deposit and control the nucleation and crystal growth of ZnO. Ethylenediamine was used to promote deposition of ZnO from zinc acetate solution. Crystalline ZnO particles or particulate films were successfully fabricated at 60 degrees C. The morphology of ZnO particles was further controlled to a hexagonal cylinder shape, long ellipse shape or hexagonal symmetry radial whiskers having high aspect ratio. The morphology was controlled by changing the supersaturation degree. Moreover, their photoluminescence was investigated. The novel solution process will contribute to the development of future ZnO devices.

Thermoelectric energy conversion technology to convert waste heat into electricity has received much attention. In addition, metal oxides have recently been considered as thermoelectric power generation materials that can operate at high temperatures on the basis of their potential advantages over heavy metallic alloys in chemical and thermal robustness. We have fabricated high-quality epitaxial films composed of oxide thermoelectric materials that are suitable for clarifying the intrinsic "real" properties. This review focuses on the thermoelectric properties of two representative oxide epitaxial films, p-type Ca 3Co 4O 9 and n-type SrTiO 3, which exhibit the best thermoelectric figures of merit, ZT (= S (2)sigma Tkappa (-1), S = Seebeck coefficient, sigma = electrical conductivity, kappa = thermal conductivity, and T = absolute temperature) among oxide thermoelectric materials reported to date. In addition, we introduce the recently discovered giant S of two-dimensional electrons confined within a unit cell layer thickness ( approximately 0.4 nm) of SrTiO 3.

Development of a guanine nanowire (G-wire) that is controllable and can be switched by external signals is important for the creation of molecular electronic technologies. Here, we constructed a G-wire in which the thymines of the main chain of d(G4T4G4) were replaced with 2,2'-bipyridine units, which have two aromatic rings that rotate arbitrarily upon coordination with metal ions. Circular dichroism of the DNA oligonucleotides with or without the 2,2'-bipyridine unit showed that divalent metal ions induce the bipyridine-containing oligonucleotide to switch from an antiparallel to a parallel G-quadruplex. Native polyacrylamide gel electrophoresis showed that the parallel-stranded G-quadruplex DNA had a high-order structure. Circular dichroism and native gel electrophoresis analyses suggested that adding Na2EDTA causes a reverse structural transition from a parallel-stranded high-order structure to an antiparallel G-quadruplex. Moreover, atomic force microscopy showed a long nanowire ( approximately 200 nm) in the presence of Ni2+ but no significant image in the absence of Ni2+ or in the presence of both Ni2+ and Na2EDTA. These observations revealed that the parallel-stranded high-order structure is a G-wire containing numerous DNA oligonucleotide strands bound together via divalent metal ion-2,2'-bipyridine complexes. Finally, we found that alternating addition of Ni2+ and Na2EDTA can cycle the G-wire between the high-order and disorganized structures, with an average cycling efficiency of 0.95 (i.e., 5% loss per cycle). These results demonstrate that a DNA oligonucleotide incorporating the 2,2'-bipyridine unit acts as a G-wire switch that can be controlled by chemical input signals, namely, divalent metal ions.

Enhancement of the Seebeck coefficient (S ) without reducing the electrical conductivity (sigma) is essential to realize practical thermoelectric materials exhibiting a dimensionless figure of merit (ZT=S2 x sigma x T x kappa-1) exceeding 2, where T is the absolute temperature and kappa is the thermal conductivity. Here, we demonstrate that a high-density two-dimensional electron gas (2DEG) confined within a unit cell layer thickness in SrTiO(3) yields unusually large |S|, approximately five times larger than that of SrTiO(3) bulks, while maintaining a high sigma2DEG. In the best case, we observe |S|=850 microV K-1 and sigma2DEG=1.4 x 10(3) S cm-1. In addition, by using the kappa of bulk single-crystal SrTiO(3) at room temperature, we estimate ZT approximately 2.4 for the 2DEG, corresponding to ZT approximately 0.24 for a complete device having the 2DEG as the active region. The present approach using a 2DEG provides a new route to realize practical thermoelectric materials without the use of toxic heavy elements.

Helical polypeptides have a highly rigid conformation. In order to control self-assembling structure in nanoscale, the rigidity of the stabilizing molecules, which is working as scaffolds, is highly important. Furthermore, the molecular lengths of polypeptides can be readily controlled by using their unique polymerization methods. In this study, we have used helical polypeptides as the stabilizing reagent of metal nanoparticles. As for rigid helical polypeptides, poly(gamma-benzyl-L-glutamate) (PBLG) was selected, and was synthesized by N-carboxylic acid anhydride (NCA) polymerization. Preparation of helical polypeptide-stabilized gold nanoparticles using a two-phase reduction process from the corresponding metal salts with NaBH4 is therefore introduced. PBLG itself did not have good stabilizing ability for metal nanoparticles and a terminal attaching ligand was indispensable for nanoparticle stabilization and, for this purpose, lipoic acid was selected. It is estimated that lipoic acid functionalized polypeptide molecules were attached perpendicularly to the particle surface by lipoic acid group. The size and structure, as well as assembling will be discussed in this manuscript.

We proposed and developed an exfoliation process for layer-structured NaxCoO2 to prepare CoO nanosheets. Na+ ion exchange by acid treatment was utilized to expand the spacing between the two CoO2 layers in NaxCoO2. Ethylamine was then effectively utilized for the exfoliation of cobalt oxide sheets having nanometer-order thickness and high aspect ratio. CoO nanosheets were observed by TEM micrographs and electron diffraction patterns after drying. Further efforts are needed for the application of exfoliated sheets to an integration process to fabricate self-assembled nanomaterials such as desired layer structures composed of two (or more) kinds of nanosheets.

We designed a gas-generated self-assembly route for patterning of ZrO2 precursor films from an aqueous peroxozirconium solution. Molecular oxygen generated during the decomposition of zirconium complex selectively aggregated on the hydrophobic surface of self-assembled monolayers, which was photo-modified to be a template. This gas layer prevented the solution from attaching to the substrate, so as the deposition of zirconia precursor occurred almost entirely on the hydrophilic sites. In comparison, only isolated islands of deposits were observed on hydrophobic sites, which may be attributed to contamination or adsorption of colloids during the preparation of samples. The resolution of pattern was well improved by using such a gas-generated process. In addition, this approach can be also extended to prepare other micropatterns.

We have developed a unique multistep film growth technique, combining reactive solid-phase epitaxy (R-SPE) with an intercalation process, to fabricate epitaxial films of superconducting sodium-cobalt oxyhydrate, Na(0.3)CoO2.1.3H2O. An epitaxial film of Na(0.8)CoO2 grown on an alpha-Al2O3(0001) substrate by R-SPE was subjected to oxidation and hydration treatment, leading to the formation of a Na(0.3)CoO2.1.3H2O epitaxial film. The film exhibited metallic electrical resistivity with a superconducting transition at 4 K, similar to that of bulk single crystals. The present technique is suitable and probably the only method for the epitaxial growth of superconducting Na(0.3)CoO2.1.3H2O.

Antisense oligonucleotides (AS ODNs) are applied to silence a particular gene, and this approach is one of the potential gene therapies. However, naked oligonucleotides are easy to be degraded or absorbed in biological condition. Therefore, we need a carrier to deliver AS ODNs. This paper presents galactose moieties that were conjugated to the side chain of SPG to enhance cellular ingestion through endocytosis mediated by asialoglycoprotein receptor specifically located on parenchymal liver cells. We introduced galactose with two types of chemical bonds; amide and amine, and the amine connection showed lower ingestion and more toxicity than the amide one. Since PEG was known to induce endocytosis escape, we combined PEG and galactose aiming to provide both cellular up-take and subsequent endocytosis escape. We designed lactose or galactose moieties to attach to the end of the PEG chain that connects to the SPG side chain. When the PEG had the molecular weight of 5000-6000, the antisense effect reached the maximum. We believe that this new type of galactose and PEG dual conjugation broaden the horizon in antisense delivery.

Zymosan, classified among beta-(1-->3)-d-glucans, is produced from the cell wall of yeast and well known to induce proinflammatory cytokines when ingested by immune cells. We found that zymosan forms a complex with immunostimulatory CpG DNA, where both zymosan and CpG DNA can induce cytokine secretion according to the different mechanisms (i.e., recognized by different receptors). The complex activated macrophages and induced cytokine secretion, more efficiently than separate administration of zymosan or CpG DNA. Microscopic observation showed that this increment of the cytokine secretion can be explained by the fact that zymosan and zymosan/CpG DNA complex are up-taken more than naked CpG DNA. Additionally, existence of two different immunostimulants in the same cells may enhance the immunoresponse. This report presents a new strategy to construct a delivering vehicle for CpG DNA and to enhance its activity with the 'cocktail effect' of the two immunostimulants.

We have developed a technique for the site-selective electroless deposition of Cu on poly(ethylene terephthalate) (PET) substrate modified with an organic self-assembled monolayer (SAM). The PET substrate was first modified with a silica-like layer by being dip-coated in an acetone solution of 3-aminopropyltrimethoxysilane and treated with UV light. The PET substrate was further modified with thiol groups using a 3-mercaptopropyltrimethoxysilane-SAM and then irradiated by UV light through a photomask to prepare thiol-group regions and OH-group regions. Cu was then deposited on only the thiol-group regions of the substrate by electroless deposition in a neutral solution with no catalysts by using dimethylamineborane as a reducing reagent. This site-selective deposition process can control the deposition conditions by an organic thin film fabricated on a surface-modified PET substrate, and thus can be applied to other low heat-resistant substrates.

Our previous work showed that a natural beta-(1-->3)-d-glucan schizophyllan (SPG) can form a stable complex with single-stranded oligonucleotides (ssODNs). When protein transduction peptides were attached to SPG and this modified SPG was complexed with ssODNs, the resultant complex could induce cellular transfection of the bound ODNs, without producing serious cytotoxicity. However, no technique was available to transfect double-stranded DNAs (dsDNA) or plasmid DNA using SPG. This paper presents a new approach to transfect dsDNA, showing preparation and transfection efficiency for a minimal-size gene having a loop-shaped poly(dA)(80) on both ends. This poly(dA) loops of dsDNA can form a complex with SPG. An siRNA-coding dsDNA with the poly(dA) loop was complexed with Tat-attached SPG to silence luciferase expression. When LTR-Luc-HeLa cells that can express luciferase under the control of the LTR promoter were exposed to this complex, the expression of luciferase was suppressed (i.e., RNAi effect was enhanced). Cytotoxicity studies showed that the Tat-SPG complex induced much less cell death compared to polyethylenimine, indicating that the proposed method caused less harm than the conventional method. The Tat-SPG/poly(dA) looped dsDNA complex had a structure similar to the viral genome in that the dsDNA ends were able to induce transfection and protection. The present work identifies the SPG and poly(dA) looped minimum-sized gene combination as a candidate for a non-toxic gene delivery system.

Schizophyllan is a natural beta-(1-->3)-d-glucan existing as a triple helix in water and as a single chain in dimethylsulfoxide (DMSO). As we already reported, when a homo-polynucleotide [e.g., poly(dA) or poly(C)] is added to the schizophyllan/DMSO solution and subsequently DMSO is exchanged for water, the single chain of schizophyllan forms a complex with the polynucleotide. One of the potential applications for this novel complex is an antisense-oligonucleotide (AS ODN) carrier. The present paper describes a modification technique that enabled us to introduce PEG only to the side chain of schizophyllan. This technique consisted of periodate oxidation of the glucose side chain and subsequent reaction between methoxypolyethylene glycol amine and the formyl terminate, followed by reduction with NaBH4. Subsequently, we made a complex from PEG-appended schizophyllan and an AS ODN sequence, and carried out an in vitro antisense assay, administrating the AS ODN complex to depress A375 c-myb mRNA of A375 melanoma cell lines. The PEG-SPG/AS ODN complex showed more enhanced antisnese effect than naked AS ODN dose, i.e., the same level as that of RGD-appended SPG. Here, the RGD system has been shown one on the most effective AS ODN carrier (Science 261 (1993) 1004-1012). When we added nigericin to the assay system, the antisense effect was not affected in the PEG-SPG system, on the other hand, it was almost eliminated in the RGD system. Nigericin is well known to interrupt transport from endosome to lysosome. Therefore, the difference between the PEG and RGD complexes indicates that, in the PEG system, AS ODN was able to escape from lysosomal degradation. The present work has thus proposed a new strategy to delivery AS ODN using schizophyllan as a new carrier.

We already found that beta-1,3-glucan polysaccharides form polymeric complexes with certain polynucleotides, but the parallel vs. anti-parallel orientation in those complexes had remained unsolved. In this paper, this controversial problem has been discussed for curdlan/oligo(dA) complexes utilizing two different energy transfer techniques. The first system consists of a combination of fluorescein-labeled curdlan and 3'-(or 5'-)tetramethyl-rhodamine (TAMRA)-labeled oligo(dA). The second system utilizes gold nanoparticles: that is, two curdlan chains were linked by a disulfide bond and after complexation with oligo(dA), the complex was immobilized on gold nanoparticles. In this system, TAMRA was attached to the 3'(or 5') end of oligo(dA) and the gold particle acted as a fluorescence quencher (energy acceptor). These experiments have led us to conclude that in the curdlan/oligo(dA) complex, parallel orientation is more favourable than anti-parallel orientation. These findings have enabled us to envision a clearer image for the complexation mode between beta-1,3-glucan polysaccharides and polynucleotides.

We investigated the formation mechanism of thermoelectric [Ca(2)CoO(3)](0.62)[CoO(2)] (CCO) on beta-Co(OH)(2) templates with maintained orientations by identifying the intermediate phases and specifying the relationship between their crystallographic orientations. We mixed beta-Co(OH)(2) templates with the complementary reactant CaCO(3) and prepared a compact by tape casting, with the developed (001) plane of the templates aligned along the casting plane. High-temperature XRD of the compact revealed that beta-Co(OH)(2) decomposed into Co(3)O(4) by 873 K, and Co(3)O(4) reacted with CaO to form CCO by 1193 K via the formation of the newly detected intermediate phase beta-Na(x)()CoO(2)-type Ca(x)()CoO(2) at 913-973 K. Pole figure measurements and SEM and TEM observations revealed that the relationship between the crystallographic planes was (001) beta-Co(OH)(2)//{111} Co(3)O(4)//(001) Ca(x)()CoO(2)//(001) CCO. The crystal structures of the four materials possess the common CoO(2) layer (or similar), which is composed of edge-sharing CoO(6) octahedra, parallel to the planes. The cross-sectional HRTEM analysis of an incompletely reacted specimen showed transient lattice images from Ca(x)()CoO(2) into CCO, in which every other CoO(2) layer of Ca(x)()CoO(2) was preserved. Thus, it was demonstrated that a textured CCO ceramic is produced through a series of in situ topotactic conversion reactions with a preserved CoO(2) layer of its template.

Thermal stabilization of the complex between polycytidylic acid [poly(C)] and the modified schizophyllan (SPG) whose hydrophilic side-chain glucose groups are selectively removed utilizing mild Smith-degradation has been investigated. With the decrease in the side-chain glucose groups of schizophyllan, the complex with poly(C) can be considerably stabilized compared with unmodified SPG; for example, the T(m) value after the removal of the side-chain glucose groups from 33.3 (unmodified) to 1.0 is enhanced by 14 degrees C. In addition, the thermal stabilization effect is even operative under the physiological conditions ([NaCl] = 0.15 mol dm(-3)). This effect is exerted owing to the construction of the hydrophobic atmosphere around the complex. Although schizophyllan lost the side-chain glucose groups, it still kept the protection effect of the bound poly(C) chain against RNaseA-mediated hydrolysis as observed for unmodified schizophyllan. The assessment of the cytotoxicity for A375:human malignant melanoma, and HL60:human promyelocytic leukemia revealed that the modified schizophyllan scarcely increases the cytotoxicity. These results indicate that the present modification for schizophyllan is of great significance in a viewpoint to develop the practical gene carriers operative even under the physiological conditions., (Copyright 2004 Wiley Periodicals, Inc.)

A natural polysaccharide schizophyllan (SPG) has been known to form a stable complex with poly(dA). We attached a poly(dA)(80) tail to the both ends of a linear double-stranded DNA, which had been prepared from a plasmid DNA vector. The poly(dA) tailed DNA verified to form complex with SPG by gel electrophoresis and atomic force microscopy (AFM). AFM images indicated that the complexes exhibit a dumbbell-like architecture, that is, quite similar to that of adenovirus genome. The complex demonstrated excellent exonuclease resistance, probably because of the protection effect by SPG complexation.

Schizophyllans carrying beta-lactoside and alpha-mannoside appendages were prepared from native schizophyllan through NaIO4 oxidation followed by reductive amination using aminoethyl-beta-lactoside and alpha-mannoside, respectively. The resulting schizophyllans form stable macromolecular complexes with polynucleotides, such as poly(C) and poly(dA). Specific affinity between these macromolecular complexes and saccharide-binding proteins was demonstrated by surface plasmon resonance and agarose gel staining assays. beta-lactoside-appended schizophyllan enhanced an antisense activity in hepatocytes which express lactoside-binding proteins on their cell surfaces.

Siloxane-anchored, self-assembled monolayers (SAMs) on single crystal Si were prepared with a variety of surface functional groups using a single commercially available surfactant (1-bromo-11-(trichlorosilyl)undecane) followed by in situ transformations. Polar (thioacetate and thiol), nonpolar (methyl), acidic (sulfonic and carboxylic), basic (various amines), and ionic (alkylammonium) surface functionalities were prepared. For primary amine and sulfonate surfaces, the degree of surface charge as a function of pH was determined ex situ using X-ray photoelectron spectroscopy (XPS). Sulfonate SAMs exhibited much higher effective pKa (approximately 2) than dilute sulfonic acid (-5 to -6), and amine SAMs exhibited much lower pKa (approximately 3) than dilute organic amines (approximately 10). This is attributed to the stabilization of nonionized groups by adjacent ionized groups in the SAM. Zeta potentials of these SAMs as a function of pH were consistent with the XPS results and indicated that ionizable SAM surfaces can generate surface potentials much higher than those of nonionic SAMs (thioacetate, methyl) and typical oxide surfaces.

Both the charged surfaces and condition of supersaturated solutions are thought to be the important factors that greatly affect the nucleation of hydroxyapatite (HAp) onto the substrates. In the present study self-assembled monolayers (SAM) terminated with amino (NH2-SAM) and hydroxyl (OH-SAM) headgroups were employed to generate the positively and negatively charged surfaces, respectively. The soaking experiments for HAp nucleation were carried out in the supersaturated solutions (1.5 SBF) with Ca2+ and PO4(3-) ions concentrations 1.5 times higher than in simulated body fluid (SBF). The stability of solutions deeply depends on pH values if other factors (temperature, ionic series and their concentration, etc.) are fixed. Consequently, the opposite micropatterns of HAp films were observed on the UV-patterned SAM with NH2 and OH terminals in a stable solution (1.5 SBF, pH=7.2) where no particles formed and in an unstable solution (1.5 SBF, pH=7.6) where homogeneous nucleation occurred. The preferential nucleation of HAp was found on negative surface (OH-SAM) in a stable supersaturated solution, while selective deposition of HAp was formed on positive surface (NH2-SAM) in the unstable solution. Considering the latter results, it is conceivable that the electrostatic adhesion of microparticles formed in the solution dominated the formation of HAp in the unstable solution.

A beta-(1 --> 3)-d-glucan schizophyllan (SPG) forms a stoichiometric complex with some polynucleotides. This communication describes our attempt to apply the SPG complex to deliver CpG DNA to endosomes to enhance cytokine secretion. To increase cellular uptake, we introduced spermine, arginine-glycine-aspartic acid tripeptide, octaarginine, or cholesterol to the SPG side chain. The chemically modified SPG showed essentially no cytotoxicity. When CpG DNA complex made therefrom was exposed to macrophages, dramatic enhancement in the cytokine secretion was observed. It increased 5-10 times from the naked dose and 100 times from the background. This performance promises that SPG can be an excellent carrier for CpG DNA.

Schizophyllan is a beta-(1-->3)-D-glucan and can form a novel complex with some single-chains of DNAs. As the preceding paper revealed, the polynucleotide bound in the complex is more stable to nuclease-mediated hydrolysis than the polynucleotide itself (i.e., naked polynucleotide). This paper examined possibility to apply this complex to an antisense DNA carrier, using an in vitro (cell-free) transcription/translation assay. In this assay, we used a plasmid DNA coding a green fluorescence protein (GFP) and an antisense DNA designed to hybridize the ribosome-binding site in the GFP-coded mRNA. When the antisense DNA was administered as the complex, a lower GFP expression efficiency (or higher antisense effect) is observed over naked DNA. This is because the antisense DNA in the complex is protected from the attack of deoxyribonuclease. When exonuclease I, which specifically hydrolyzes single DNA chains, was present in the GEP assay system, the antisense effect was not changed for the complex while being weakened in the naked antisense DNA system. These results imply that the exonuclease I cannot hydrolyze the antisense DNA in the complex, while it can hydrolyze naked DNA to reduce its antisense effect.

Schizophyllan is a beta-(1-->3)-D-glucan existing as a triple helix in water and as a single chain in dimethylsulfoxide (DMSO), respectively. As we already reported, when some homo-polynucleotide (for example, poly(dA) or poly(C)) is added to the schizophyllan/DMSO solution and subsequently DMSO is exchanged for water, the single chain of schizophyllan (s-SPG) forms a complex with the polynucleotide. The present work demonstrates that the polynucleotide bound in the complex is more stable to nuclease-mediated hydrolysis than the polynucleotide itself (i.e., naked polynucleotide), using high-performance liquid chromatography and ultraviolet absorbance technique. A kinetic study for the hydrolysis clarified that the simple Michaelis-Menten relation is held and the maximum velocity for the complex is one-sixth as small as that of the naked polynucleotide. This low hydrolysis rate for the complex suggests that s-SPG is applicable to a carrier for antisense oligonucleotides.

We studied the direct micropatterning of a lanthanum-based thin film on a template of self-assembled monolayers in an aqueous solution at 80 degrees C. The template composed of silanol and octadecyl areas was prepared by UV-modified octadecyltrichlorosilane SAMs through a photomask. The amorphous La(2)O(CO(3))(2) x H(2)O thin films were selectively deposited in the silanol regions. Crystallized La(2)O(3) was obtained after heating at 800 degrees C in air.

Schizophyllan is a natural beta-(1-->3)-D-glucan that exists as a triple helix in H(2)O and as a single chain in dimethylsulfoxide (DMSO) or basic solution (pH >13). As we have already reported, when a homo-polynucleotide (e.g., poly(dA), poly(A), or poly(C)) is added to a schizophyllan/DMSO solution, and, subsequently, DMSO is exchanged for H(2)O, the single chain of schizophyllan forms a complex with the polynucleotide. Since eukaryotic mRNAs have poly(A) tails, we hypothesized that schizophyllan can bind to mRNA by interacting with this tail. However, we have not yet observed complexation between schizophyllan and mRNA after exchanging DMSO for H(2)O. In this report, we show that the complexation can be accelerated when the solution pH is changed from 13 to 7-8 in the presence of schizophyllan and polynucleotides. By this approach, we found that schizophyllan forms a complex with a yeast mRNA.