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This paper reports on the preparation and characterisation of pelletised glass electrolytes that were fabricated with a proton conducting glass derived from a sol–gel technique, and several kinds of binders. The electrolytes, consisting of a glass powder that had been pulverised by planetary ball milling and mixed with an orthophosphoric acid binder, gave rise to a maximum proton conductivity of 1.3 × 10–2S cm–1measured at 80 °C and 80% relative humidity. The pore diameter of the PGE was in this case ∼2 nm. The hydrogen gas permeability was analysed as a function of the temperature and was found to be on the order of 10–10mol cm–1s–1Pa–1at 100 °C. Current–voltage measurements were carried out at room temperature using the PGE under H2and O2flow. Power densities were obtained from the I–V curves during fuel cell operation at 80 °C and 100% R.H.

Phosphosilicate glass membranes doped with a mixture of titania oxide (TiO2) and zirconium oxide (ZrO2) were prepared. Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric and differential thermal analysis, pore, impedance, and permeability studies as well as electrochemical analysis were carried out. The specific surface area and pore distributions were described by the Brunauer−Emmett−Teller (BET) method, and the average pore size was found to be approximately 2.2 nm for all composite glass membranes. The FTIR analysis displayed a maximum intensity in the range of 1000−1200 cm-1, indicating the presence of Si−O−Si bonds in the glass composites. A high proton conductivity of 5.8 × 10-3S cm-1was obtained for one of the membranes at 80 °C and 50% RH. The permeability was measured for a hydrogen flow background and was found to decrease from 1.41 × 10-11to 3.83 × 10-12mol/cm s Pa as the temperature from 30 to 110 °C.

A novel structure for an H2/O2fuel cell with a proton conducting glass electrolyte and a Pt/C catalyst was developed. The performance of the fuel cell, which was impregnated with a glass electrolyte and a gaseous hydrogen–oxygen feed at low temperature in a humidified atmosphere was significantly improved by introducing membrane electrode assemblies (MEAs) consisting of heteropolyacids (HPAs) (phosphotungstic acid, PWA and phosphomolybdic acid, PMA) doped with a P2O5‐SiO2glass electrolyte. The HPAs containing porous glass electrolytes show promise for applications in low temperature H2/O2fuel cells. The electrochemical behaviour of these materials was studied by measuring the current–voltage profile from polarisation curves. A maximum power density of ≈ 35 mW cm–2was obtained at 30 °C and 30% RH (relative humidity) using a PMA/PWA‐P2O5‐SiO2glass electrolyte membrane. The impedance measurements displaying the total cell ohmic resistance for 12 h at 0.5 V were evaluated at 30 °C. The resistance value was 3.5 Ω for an operating time of 12 h. This MEA showed the best and the most stable performance for use in an H2/O2fuel cell.

Abstract Carbonate containing hydroxyapatite (CO3HAp) is one of the candidate materials as a bioresorbable bone substitute. In the present work, CO3HAp was efficiently prepared by a hydrothermal treatment of calcium tripolyphosphate gel with urea at 140 °C for 24 h. Chemical potential plots of the CO3HAp for estimation of its dissolution behavior suggested that the CO3HAp is more soluble than hydroxyapatite (HAp) and is as soluble as octacalcium phosphate (OCP) and/or ß -tricalcium phosphate (TCP). This material is expected to be applied to bioresorbable materials such as bone fillers.

The formation of a porous coating is the decisive feature for the bio‐compatibility of silica‐free calcium phosphate glass ceramics on alloy surfaces like the β‐Ti structured Ti‐29Nb‐13Ta‐4.6Zr used in this work. The ceramic composition is highly important: 50 CaO‐40 P2O5‐7 Na2O‐3 TiO2glass powder produces a pore‐free coating unable to bind hydroxyapatite, whereas 60 CaO‐30 P2O5‐7 Na2O‐3 TiO2glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure).

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The sol-gel method was applied to the preparation of glasses doped with nano-sized CdS and SnO₂ particles of 5–10nm in diameter. Band gap energies of the nano-sized particles exhibited large blue shift compared with those of bulk crystals and the energy shift was reciprocally proportional to the square of the particle size. The third order nonlinearity of the nano-sized CdS particles showed the maximum value of 1.5610-10 esu at the optical absorption edge position. The Eu³⁺ ions were doped in the nano-sized CdS and SnO₂ particles-precipitated glasses, of which the fluorescence intensities were enhanced by the existence of the nano-sized particles. The energy absorbed by the quantum-dot effect in the nano-sized particles is efficiently transferred into the Eu³⁺ ions to cause the high emission. Particularly, the Eu³⁺ ions doped in nano-sized SnO₂-containing glasses exhibited the enhanced fluorescence of the ⁵D₀→⁷F_j transitions. When excited at the energy corresponding to the absorption edge of the SnO₂ nanocrystals, the fluorescence intensities of the Eu³⁺ ions were enhanced up to 150 times higher than the glass without nanocrystals.

Proton conduction in sol−gel-derived porous glasses was investigated and is related to the pore structure. The porous P2O5−SiO2 glasses absorb water under ambient conditions and consequently increase the electrical conductivity. In glasses having pores ~5 nm or smaller, the water molecules diffuse through the pores and totally fill the pores. The motion of the water molecules is restricted in small pores, and the absorbed water molecules are well retained even at low humidity. The conductivity of this glass was high in the temperature range down to −20 °C. On the other hand, in glasses with large pores, no confinement effect occurred for the water molecules and the conductivity suddenly decreased below 0 °C.

Sol−gel derived gold/silica glasses, starting with Au sols prepared by two different methodologies, one without the aid of any external stabilizing agent and the other with silica-coated Au, are described. The optical absorption spectra show the typical surface plasmon resonance for Au at around 520−530 nm. Transmission electron microscopy reveals the existence of spherical Au particles in the silica matrix. The mean diameters of Au nanoclusters in gels and glasses vary from 10 to 20 nm and from 27 to 38 nm, respectively, supported by X-ray diffraction data. The third-order optical nonlinearities |χ⁽³⁾| determined by a degenerate four-wave mixing (DFWM) method exhibit a higher value of 2.2 × 10^-9 esu for a glass with 0.5 wt % Au heated at 600 °C indicating that a larger size induces an enhancement effect. This method also offers a greater χ⁽³⁾/α (α:  absorption coefficient) value of 1 × 10^-11 esu cm, which is comparable to those values obtained by a sputtering method. Thus, these novel Au−SiO2 nanocomposites fabricated by facile sol−gel methods render them potential candidates for photonic applications.

Al2O3−SiO2 glasses were prepared for doping with Sm³⁺ ions using a sol−gel method, followed by X-ray irradiation, in which formation of the Sm²⁺ ions and persistent spectral hole burning (PSHB) were investigated. The X-ray irradiation brought about hole centers in the oxygen ions bound with Al³⁺ ions. And the released electrons are captured in the Sm³⁺ ions to form Sm²⁺ ions. The X-ray reduced Sm²⁺ ions are not so stable that they change into Sm³⁺ by heating at 200 to 300 °C. The spectral holes were burned in the ⁷F0→⁵D0 line of the Sm²⁺ ions, in which deep holes could be burned within a short laser-irradiation period compared with that of the H2-gas heated glass. Hole spectra were stable up to room temperature, at which the hole depth was ~20% of the total fluorescence intensity. Bleaching at the low energy sites of the ⁷F0→⁵D0 transition was observed during irradiation with the laser. The results definitely reveal that the PSHB is formed by the electron transfer between the Sm²⁺ ions and the hole centers formed in oxygen ions bound through the excited ⁵D0 state.

Highly proton conducting organic‐inorganic glass hybrids were prepared using the sol‐gel method, the electrical conductivities of which were studied in relation to their thermal and mechanical properties. The solution of hydrolyzed Si(OC2H5)4and H3PO4was reacted with a perfluorosulfonic polymer such as Nafion, forming a homogeneous hybrid‐gel. The conductivity of the hybrid‐gel incorporated with 20 % Nafion is ∼10 mS/cm at room temperature, which increases as the treatment temperature increases and reaches ∼ 60 mS/cm at 200 °C. The hybrid continues to exhibit high conductivity after heating to 250 °C and improved mechanical property over the inorganic glass.

Electrodeposition was used for the codeposition of glucose oxidase enzyme and a gold nanoparticle–silicate network onto an indium tin oxide (ITO) glass electrode. This co-entrapment of glucose oxidase enzyme in a gold nanoparticle–silicate network imparts biocatalytic activity to the film. The gold nanoparticles in the network catalyse the oxidation and reduction of H₂O₂, the by-product of the enzymatic reaction. The low operating potential of the sensor eliminates the interference from common interferents, such as acetaminophen, ascorbic acid, dopamine, etc.

A general methodology to prepare redox active inorganic multilayers consisting of copper hexacyanoferrate layers formed by successive self-assembly and solution epitaxy is described. The layers are separated by a mercaptopropionic acid spacer.

Electrochemical organization of a thin film of gold nanoparticles from an aminosilicate-stabilized gold sol on an indium tin oxide coated glass is demonstrated. Films are semitransparent to reflectivity depending on the thickness and have three-dimensional conductivity. Characterization of the films using UV−visible spectroscopy, IR spectroscopy, atomic force microscopy, and cyclic voltammetry has shown that they are made of a network of gold nanoparticles that are interconnected by aminosilicate moieties. This methodology is successfully extended to codeposited glucose oxidase enzyme, based on which a glucose biosensor is demonstrated.

Water diffusion and its role on the proton conduction are discussed in the sol−gel-derived porous P2O5−SiO2 glasses. The diffusion coefficient of water in the glass is ~10^-7 cm²/s at room temperature. The electrical conductivity is proportional to the logarithm of the number of water molecules with three separate lines in response to the water concentration. The activation energy determined from the spin−lattice relaxation of proton is, ~10 kJ/mol, independent of the water concentration, whereas the activation energy for proton conduction decreases to ~10 kJ/mol with increasing water concentration.

Human chromosomes 1q21-q25, 6p21.3-22.2, 9q33-q34, and 19p13.1-p13.4 carry clusters of paralogous loci, to date best defined by the flagship 6p MHC region. They have presumably been created by two rounds of large-scale genomic duplications around the time of vertebrate emergence. Phylogenetically, the 1q21-25 region seems most closely related to the 6p21.3 MHC region, as it is only the MHC paralogous region that includes bona fide MHC class I genes, the CD1 and MR1 loci. Here, to clarify the genomic structure of this model MHC paralogous region as well as to gain insight into the evolutionary dynamics of the entire quadriplication process, a detailed analysis of a critical 1.7 megabase (Mb) region was performed. To this end, a composite, deep, YAC, BAC, and PAC contig encompassing all five CD1 genes and linking the centromeric +P5 locus to the telomeric KRTC7 locus was constructed. Within this contig a 1.1-Mb BAC and PAC core segment joining CD1D to FCER1A was fully sequenced and thoroughly analyzed. This led to the mapping of a total of 41 genes (12 expressed genes, 12 possibly expressed genes, and 17 pseudogenes), among which 31 were novel. The latter include 20 olfactory receptor (OR) genes, 9 of which are potentially expressed. Importantly, CD1, SPTA1, OR, and FCERIA belong to multigene families, which have paralogues in the other three regions. Furthermore, it is noteworthy that 12 of the 13 expressed genes in the 1q21-q22 region around the CD1 loci are immunologically relevant. In addition to CD1A-E, these include SPTA1, MNDA, IFI-16, AIM2, BL1A, FY and FCERIA. This functional convergence of structurally unrelated genes is reminiscent of the 6p MHC region, and perhaps represents the emergence of yet another antigen presentation gene cluster, in this case dedicated to lipid/glycolipid antigens rather than antigen-derived peptides.

A simple strategy is presented for the construction of an electrochemical interface with a tunable kinetic barrier by self-assembling organically modified silica gel and gold nanoparticles. Self-assembly of an organically modified silica layer is carried out from the hydrolyzed sol of the precursor mercaptopropyltrimethoxysilane. The kinetic barrier of this self-assembled silicate film is modified by gold nanoparticles that are self-assembled into the silicate network. The electrochemistry of ferricyanide redox reaction is used as a marker to probe the interface.

A simple methodology has been developed to enable a greater enhancement of fluorescence from europium (Eu³⁺)-doped silica gels containing adsorbed silver (Ag) islands. The procedure involves the preparation of Eu³⁺-doped silica gels by a sol−gel method and then immersion in a Ag sol for ca. 48 h to allow the adsorption of Ag islands on the pore surfaces of silica gels. UV−vis spectra show the characteristic surface plasmon resonance of the Ag at around 390 nm, and transmission electron microscopy (TEM) presents Ag islandlike particles on the surface of silica gels. The photoluminescence studies reveal the fact that the enhanced fluorescence originates from the local field enhancement around Eu³⁺ ions, caused by the electronic plasmon resonance of the Ag islands.

Polystyrene-block-poly(2-vinylpyridine) with different block lengths, viz., 190−190 and 800−860 monomer units, have been employed in order to obtain monodisperse Au nanoparticles, dispersed in a polypyrrole (PPY) matrix. In consonance with optical absorption spectra, the formation of a nanodispersion of Au has been corroborated by Mie−Drude theory. The annealing process yields a single Au nanocluster (core) in each micelle, covered by a PPY shell, forming unique core−shell particles. By variation of the block length of the polymer, different sizes of Au nanoclusters, ranging from 7 to 13 nm, covered by a PPY shell within the spherical microdomains of the block copolymer, have been prepared. Different shapes of Au particles, viz., spherical, cubic, tetrahedral, and octahedral, have been observed, with a little nudge in the preparative strategies. Furthermore, we have also observed elegant dendritic nanostructures of Au−PPY in another different approach, by employing vapor phase polymerization of pyrrole onto solution-cast films of block copolymer ionomers. These novel Au−PPY nanocomposites could open up new avenues in the field of molecular electronics.

Abstract: The immediately early gene product c-fos is known to be induced in neurons under noxious stimuli. Therefore, the immunohistochemistry of c-fos expression in human brains might offer information on the localization of stimulated neurons. In this study, the immunohistochemical localization of c-fos was studied in the neurons of the hypoglossal nucleus (XII), the dorsal motor nucleus of the vagal nerve (X), the nucleus solitarius (Sol), the accessory cuneate nucleus (Cun), the spinal trigeminal nucleus (V) and the inferior olive (Oli) of the human medulla oblongata from forensic autopsy cases. The neurons in the X nucleus showed the highest percentage of positive reactions for c-fos, followed in descending order by the Cun, V, Oli, XII and Sol. The c-fos immunoreactivity in the Cun and X was statistically significantly higher than in the Sol, XII and Oli. Although neurons in the Sol are known to be involved in respiration, there was no statistically significant difference in the c-fos immunoreactivity in the neurons in the Sol between asphyxia and non-asphyxia cases. On the other hand, the percentage of neurons positive for the c-fos immunoreactivity was statistically significantly higher in the Oli of asphyxia cases than of non-asphyxia cases. Our results indicate the difference in the immunoreactivity of c-fos among the nuclei of the human medulla oblongata and that the c-fos immunoreactivity in the Oli might assist the diagnosis of asphyxia.

High proton conducting P2O5−SiO2 glasses were prepared using the sol−gel method, the electrical conductivities of which were studied in relation to the pore structure and the adsorbed water. The pore properties of SiO2 and P2O5−SiO2 glasses were controlled by addition of formamide during the gel synthesis, the specific surface areas of which were changed from 200 to 900 m²/g-glass. These glasses absorb water molecules on exposure to a humid atmosphere. The conductivity increased with increasing logarithm of water concentration and reached a saturated value above the water vapor pressure of 0.8. The highest conductivity, 2 × 10^-2 S/cm at room temperature, was achieved by 5P2O5−95SiO2 glass heated at 700 °C and absorbing the water molecules.

Cordierite glass was prepared by the sol-gel process from magnesium, Al(OC4H9)3 and Si(OC2H5)4. The solution having cordierite-like structure was formed by refluxing the raw materials, followed by gelling and drying to 150° C in the saturated water vapour to hydrolyse completely. On heating the gel, AlO6 groups transformed into AlO4 groups, in which aluminium ions were incorporated in SiO4 tetrahedra units to form a Si-O-Al network structure. The gel was converted into the transparent dense glass by heating above 850° C. The glass transition temperature, 820° C, thermal expansion coefficient, 3.1×10-6° C-1, Vickers hardness, 6.22 GPa and density, 2.59 g cm-3 were almost the same as those of the conventional glass.

The purpose of this study was to determine whether the enhanced proliferative activity of splenocytes induced by exposing mice to whole body, chronic, intermittent low doses of ionizing radiation is associated with an increase in the expressioon of stress protein genes. Mice were exposed to a γ-irradiation protocol of 0, 0·04 or 0·10 Gy/day for 5 consequent days/week, for 4 weeks. Splenocytes were then assessed for their levels of heat shock protein (HSP) 70 mRNA, glyceraldehyde 3-phosphate dehydrogenase (GAPD) mRNA, HSC70 (a constitutively-expressed isoform of HSP70) and HSP72 (an inducible isoform of HSP70), before and 1 day after mitogenic stimulation. Splenocytes from mice exposed to 0·04 Gy/exposure contained elevated constitutive levels of HSP70 mRNA, HSC70 and HSP72. These splenocytes responded to T, but not B, cell mitogens by further increasing their levels of HSP70 mRNA, HSC70 and HSP72 and by mounting a heightened proliferative response. However, an exposure of 0·10 Gy was ineffective. Thus, the constitutive levels of HSP70 mRNA, HSC70 and HSP72 and the mitogen-stimulated levels of HSC70 and HSP72 of splenocytes from mice exposed to 0·10 Gy/exposure were comparable with those of sham-irradiated mice. Moreover, their proliferative activity in response to mitogenic stimulation was also comparable with that of splenocytes from sham-irradiated mice.

CdSxSe1-x solid solution microcrystal-doped glasses with a significant quantum-sized effect were prepared by the sol-gel process. Gels synthesized by the hydrolysis of complex solution of Si(OC2H5)4, Cd(CH3COO)2·2H2O and selenium were treated in H2S and hydrogen gas atmospheres to form CdSxSe1-x solid solution crystals, whose compositions were determined from the X-ray diffraction and Raman scattering spectra. Sulphur in CdS crystals is substituted for selenium by heating in hydrogen gas, and its content decreases with increasing temperature. On the other hand, the sulphur content increases on reacting the CdSe crystalprecipitated glasses with H2S gas. The optical absorption spectra are shifted towards the red as the crystal size increases, and the gap energy is reciprocally proportional to the square of the crystal size.