The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinel. When the size distribution of ruthenium particles measured by transmission electron microscopy was used as the link between the catalyst material and the theoretical treatment, the calculated rate was within a factor of 3 to 20 of the experimental rate. This offers hope for computer-based methods in the search for catalysts.

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Carbon nanotubes are shown to be useful materials for introduction of nanopores with a controlled diameter into zeolite single crystals. The intracrystalline nanopores are created by crystallization of the zeolite around the carbon nanotubes that are subsequently removed by combustion.

Heterogeneous catalysis H 2000Ammonia Synthesis from First-Principles Calculations. -DFT calculations are used to predict the rate of NH3 synthesis over a nanoparticle Ru catalyst. The results are in good agreement with rate measurements performed over a wide range of industrially relevant synthesis conditions. The only experimental input included is the particle size distribution for the Ru catalyst, which is determined from TEM. It is suggested that DFT calculations may be useful for computer-based methods in the search for catalysts. -(HONKALA, K.; HELLMAN, A.; REMEDIAKIS, I. N.; LOGADOTTIR, A.; CARLSSON, A.; DAHL, S.; CHRISTENSEN, C. H.; NOERSKOV*, J. K.; Sci. (Washington, D. C., USA) 307 (2005) 5709, 555-558; Dep. Phys., Tech. Univ. Den., DK-2800 Lyngby, Den.; Eng.) -W. Pewestorf 17-025

Recently, we have developed a new electron crystallography (EC) method for study of three dimensional (3D) structures of silica-mesoporous materials, and the 3D-structural solutions of MCM-48 and SBA-1, -6, and -16 were briefly reported. The method gives a unique structure solution through the Fourier sum of the 3D-structure factors, both amplitudes and phases, which are obtained from Fourier analyses of a set of highresolution electron microscope (HREM) images. The method was fully described in an application for structure analyses of two MCM-48 crystals with different crystal morphologies. Little structural difference was observed between the two crystals, although small differences in the structure factors were observed. The space group of MCM-48 was determined to be Ia3 hd, and the wall surface of the two crystals followed exactly the periodic minimal surface of gyroid (G). The wall separated two interpenetrating and noninterconnecting channel systems with different chiralities. After structural analysis of MCM-48, the structures of two different carbon networks, CMK-1 and CMK-4, which were synthesized within the channels of MCM-48 from different carbon sources, were studied by electron microscopy (EM). It was observed that in both cases carbon networks were equally formed in the two channels of MCM-48 without changing the space-group symmetry and that the symmetry of Ia3 hd was retained after the dissolution of silica mesoporous MCM-48 for CMK-4 but changed to I4 1 /a for CMK-1. The simplest model for structure change in CMK-1 was proposed on the basis of the observations of extra reflections in ED patterns and domain structures in HREM images as that the carbon networks equally formed in two noninterconnecting channels of MCM-48 were displaced during the dissolution relative to each other without rotation along the [001] axis by keeping each network rigidly. It is stressed that the method must be extended further for structural study of new materials with orders in two different lengths scales, atomic and mesoscopic scales.

Identification of genes associated with pain insensitivity syndromes can increase the understanding of the pathways involved in pain and contribute to the understanding of how sensory pathways relate to other neurological functions. In this report we describe the mapping and identification of the gene responsible for loss of deep pain perception in a large family from northern Sweden. The loss of pain perception in this family is characterized by impairment in the sensing of deep pain and temperature but with normal mental abilities and with most other neurological responses intact. A severe reduction of unmyelinated nerve fibers and a moderate loss of thin myelinated nerve fibers are observed in the patients. Thus the cases in this study fall into the class of patients with loss of pain perception with underlying peripheral neuropathy. Clinically they best fit into HSAN V. Using a model of recessive inheritance we identified an 8.3 Mb region on chromosome 1p11.2-p13.2 shared by the affected individuals in the family. Analysis of functional candidate genes in the disease critical region revealed a mutation in the coding region of the nerve growth-factor beta (NGFB) gene specific for the disease haplotype. This NGF mutation seems to separate the effects of NGF involved in development of central nervous system functions such as mental abilities, from those involved in peripheral pain pathways. This mutation could therefore potentially provide an important tool to study different roles of NGF, and of pain control.

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials. Our analysis of catalysts, a hydrogen storage material, and different semiconductor devices shows that features with a diameter as small as 1-2 nm can be resolved in three dimensions by electron tomography. For partially crystalline materials with small single crystalline domains, bright-field TEM tomography provides reliable 3D structural information. HAADF-STEM tomography is more versatile and can also be used for high-resolution 3D imaging of highly crystalline materials such as semiconductor devices.

Novel mesoporous TS-1 catalyst is shown to be active in epoxidation of oct-1-ene and significantly more active in epoxidation of cyclohexene than conventional TS-1.