Structure property relationships affecting the proton conductivity in imidazole loaded Al-MOFs.

The structures of the imidazole loaded derivatives of Al-MIL-53 [Al(OH)(1,4-BDC-(CH3)x)] (x = 0, 1, 2) and CAU-11 ([Al(OH)(SDBA)]) (1,4-H2BDC = terephthalic acid; H2SDBA = 4,4'-sulfonyldibenzoic acid) were determined from powder X-ray diffraction data. Impedance spectroscopy measurements were carried out to evaluate their proton conductivities under anhydrous conditions at temperatures up to 110 °C. In Al-MIL-53-(CH3)x_HIm (x = 0, 1, 2) the formation of hydrogen bonds between the framework and the guest molecules results in a decrease in proton conductivity (x0 = 1.7 × 10-6, x1 = 1.9 × 10-8 and x2 = 1.7 × 10-9 S cm-1 at 110 °C and Eact = 0.42, 0.41 and 0.46 eV, for 0, 1 and 2 CH3-groups, respectively). The highest conductivity has been measured for CAU-11_HIm with 3.0 × 10-4 S cm-1 at 110 °C (Eact = 0.19 eV), where no host-guest hydrogen bonding interactions are observed.

Anchoring of Functional Dye Molecules in MCM-41 by Microwave-Assisted Hydrothermal Cocondensation.

Covalent anchoring of functional dyes in the pores of a mesoporous silicate host Si-MCM-41 (shown in the picture) is achieved with the microwave-assisted cocondensation presented here. The short reaction time (20 min) ensures that no dye degrades during the hydrothermal synthesis.

Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical reactivity.

Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mössbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mössbauer spectra on temperature and particle size is explained by the influence of superparamagnetic relaxation effects. The coexistence of a paramagnetic doublet and a magnetically split component in the spectra is further explained by a distribution in particle size. From Mössbauer parameters the oxide phase can be identified as low-crystallinity ferrihydrite oxide. In agreement with quantum size effects observed in UV-visible studies, TEM measurements determine the size of the particles in the range 5-8 nm. The particles are mainly arranged alongside the pore walls of the alumina template. TiO2 nanoparticles are formed by depositing 2 in mesoporous alumina template. This produces metallic Ti, which is subsequently oxidized to TiO2 (anatase) within the alumina pores. UV-visible studies show a strong quantum confinement effect for these particles. From UV-visible investigations the particle size is determined to be around 2 nm. XPS analysis of the iron- and titania- embedded nanoparticles reveal the presence of Fe2O3 and TiO2 according to experimental binding energies and the experimental line shapes. Ti4+ and Fe3+ are the only oxidation states of the particles which can be determined by this technique. Hydrogen reduction of the iron/iron-oxide nanoparticles at 500 degrees C under flowing H2/N2 produces a catalyst, which is active towards formation of carbon nanotubes by a CVD process. Depending on the reaction conditions, the formation of smaller carbon nanotubes inside the interior of larger carbon nanotubes within the alumina pores can be achieved. This behavior can be understood by means of selectively turning on and off the iron catalyst by adjusting the flow rate of the gaseous carbon precursor in the CVD process.

Laboratory evaluation of a living attenuated vaccine against bluetongue type 20 virus.

Living attenuated bluetongue Type 20 virus vaccine was tested in 9 to 12 month-old Australian Merino sheep, held in air conditioned, insect-free accommodation. The vaccine appeared avirulent and immunogenic and protected against infection with a second dose of homologous vaccine virus. No enhancement of virulence or significant change in immunogenicity was observed when the vaccine was passaged 3 times through sheep without antibody to bluetongue virus.

A clearance test in mice using non-adapted viruses to determine the immunogenicity of influenza strains.

A test for the immunogenicity of influenza viruses is described, which is based upon the intranasal vaccinating dose required to induce inhibition of multiplication of unadapted influenza viruses in the lungs of mice. This test is more sensitive than an antigen extinction procedure, in which immunogenicity is measured according to the dose required to induce the formation of hemagglutination-inhibition antibody. The clearance test has been used to demonstrate that a) influenza A/Northern Territory/60/68 virus is a better immunogen than A/Victoria/3/75 and both are probably superior to A/U.S.S.R./92/77; b) for A/Northern Territory/60/68, vaccination by the intranasal route in 25 g mice is at least 43,600 times more efficient than by the intraperitoneal route and c) common immunogenic relationships exist between various H3N2 viruses and an H1N1 strain.

A murine model for assessment of living attenuated influenza A vaccines.

The laboratory mouse was evaluated as a model to assess the genetic stability of influenza A mutants of potential use as living vaccine strains. The growth of three mutant recombinants, A/Hong Kong/68-ts-1E (H3N2), A/HK/123/77x-ts-1A2 (H1N1) and A2/AA/6/60-ca(H2N2) was studied in 15 g mice. Yields of ts-1E from both lungs and turbinates were ten-fold less than that of a control virus with the same surface antigens. All ts-1E isolates showed evidence of loss of ts phenotype. Ts-1A2 and ca recombinants grew to a much lower titre than those of ts-1E, and revertants were obtained from one ts-1A2 lung isolate and one ca turbinate isolate. In other studies with hamsters, the stability of the ts character of these mutants during replication in the lungs of hamsters has been shown to be correlated with their residual virulence for man (Murphy et al., 1972; Murphy et al., 1974; Richman et al., 1977). The results from the present study suggest that the laboratory mouse is at least as sensitive as the hamster as an in vitro model for the detection of ts revertants.