All too human?

Review of three books: 'Music and humanism: an essay in the aesthetics of music' by R A Sharpe; 'The spheres of music: a gathering of essays' by Leonard B Meyer; Critical entertainments: music old and new' by Charles Rosen, which appeared in Musical Times Autumn 2001

Synthesis of Pentafluorinated β‑Hydroxy Ketones

The LHMDS-promoted in situ generation of difluoroenolates from readily available 1-aryl and 1-alkyl 2,2,4,4,4-pentafluorobutan-1,3-dione hydrates has been used to produce a series of pentafluorinated β-hydroxy ketones in up to 95% yield. The reaction proceeds under mild conditions, tolerates a wide range of functional groups, and is complete within 10 min. Reduction toward the corresponding 1,3-diol with DIBAL gives quantitative amounts and favors the formation of the <i>syn</i>-isomer

Synthesis of Pentafluorinated β‑Hydroxy Ketones

The LHMDS-promoted in situ generation of difluoroenolates from readily available 1-aryl and 1-alkyl 2,2,4,4,4-pentafluorobutan-1,3-dione hydrates has been used to produce a series of pentafluorinated β-hydroxy ketones in up to 95% yield. The reaction proceeds under mild conditions, tolerates a wide range of functional groups, and is complete within 10 min. Reduction toward the corresponding 1,3-diol with DIBAL gives quantitative amounts and favors the formation of the <i>syn</i>-isomer

Understanding Size-Dependent Morphology Transition of Triangular MoS₂ Nanoclusters: The Role of Metal Substrate and Sulfur Chemical Potential

Molybdenum disulfide (MoS₂) nanoclusters have recently attracted enormous interest, due to their promising applications as catalysts in hydrodesulfurization of fossil fuels. It has been demonstrated that the catalytic activity of MoS₂ nanoclusters closely relates to their equilibrium morphology, which is in turn quite sensitive to various factors, such as the synthesis environments, the cluster size, and the substrates. Here, we carry out the density functional theory (DFT) calculations to study the size-dependent morphology change of triangular MoS₂ nanoclusters with all these factors systematically considered. Our results indicate that the stability of triangular MoS₂ nanoclusters is mainly determined by their edge and corner energies, and the variation of the ratio of the edge to corner energies with respect to the cluster size, chemical potential of sulfur, and substrates could induce a structural transition for their equilibrium morphology. By setting the chemical potential to fit experimental conditions, our calculations reveal a size-dependent morphology transition of triangular MoS₂ nanoclusters on Au(111) substrate, which is quantitatively consistent with experiments. In addition, the electronic structures of triangular MoS₂ nanoclusters are carefully studied. The results indicate that the metallic edge states, which is important for the hydrodesulfurization catalysis, are very sensitive to the substrates and only the clusters with Mo edge on Au(111) is found to have the one-dimensional metallic edge states. This result implies that in addition to the Mo edge, the metallic substrates may also play an important role in understanding the experimentally observed catalytic activity of MoS₂ nanoclusters, which has never been considered before

Surface Structure of Organosulfur Stabilized Silver Nanoparticles Studied with X‑ray Absorption Spectroscopy

With the recent determination of the unexpected surface structure for thiolate-protected gold nanoparticles (−SR–Au–SR– staple-like motif for Au₁₀₂), it is of great interest to determine whether or not similar systems such as silver exhibit this special surface structure. A detailed study of the structure and composition of a series of organosulfur-stabilized silver nanoparticles (AgNPs) was carried out using X-ray absorption near-edge (XANES) and extended X-ray absorption fine structure (EXAFS) from a multielement (Ag, S) and multicore (Ag K- and L-edge) perspective. It was determined that AgNPs of varied sizes prepared with dodecanethiol did not exhibit either a staple-like surface structure or the traditional metal–thiolate structure (e.g., thiolate on 3-fold hollow site of metal surface), and instead adopted a layer of silver sulfide on the surface of metallic silver cores. The amount of the sulfide formed was found to be dependent on the AgNP size. Moreover, a comparison of the surface structure of thiolate-AgNPs with those coated with didodecyl sulfide indicated that the formation of a sulfide layer was inhibited when didodecyl sulfide was used achieving a surface structure more akin to the traditional thiolate bonding. These results show that AgNPs can be tailored to have different surface structure and bonding depending on the silver/sulfur molar ratio of the starting materials and type of organosulfur ligand used and, importantly, that the resulting bonding between silver and sulfur is very different from that of gold and sulfur

Hyperglycosylated proteins in DG deficient neural stem cells were also recognized by VIA4-1 and some were sensitive to peptide N-glycosidase F.

<p>Lysates of DG-deficient neural stem cells with or without LARGE overexpression were immunoprecipitated with VIA4-1 antibody. (A) The immunoprecipitates were analyzed by immunoblotting with IIH6C4. (B) The VIA4-1 immunoprecipitates were treated with PNGase F and analyzed by immunoblotting with IIH6C4. Abbreviation: DGKO, dystroglycn knockout; IP, immunoprecipitation.</p

Laminin binding by non-α-DG glycoproteins in LARGE overexpressing DG-deficient cells was blocked by IIH6C4.

<p>IIH6C4 antibody was added to the culture medium of neural stem cells, laminin was added, and bound laminin was detected by immunofluorescence staining. (A, C, E, and G) Wildtype neural stem cells. (B, D, F, and H) DG-deficient neural stem cells. (A', C', E', and G') Wildtype neural stem cells treated with IIH6C4. (B', D', F', and H') DG-deficient neural stem cells treated with IIH6C4. (I) Quantification of bound laminin. Scale bar in H': 50 µm.</p

Quantification of laminin binding on neural stem cells.

<p>(A) Comparison of overall laminin immunofluorescence intensities for wildtype and DG-deficient neural stem cells with or without LARGE overexpression after incubating with laminin for 1, 6, and 12 hrs. (B) Distribution of aggregate fluorescence intensities. Y-axis shows the percentage of laminin aggregates with fluorescence intensities greater than those shown on the X-axis. (C) Quantification of filamentous and dot–shaped laminin aggregates. (D) Average fluorescence intensities of filamentous aggregates in wildtype and DG-deficient cells with or without overexpression of LARGE. (E) Number of cells in the images analyzed for (A). Images from the 12 hour data point were used for (B, C, and D). Abbreviations: DGKO, DG knockout; WT, wildtype.</p

Establishment of dystroglycan-deficient neural stem cells.

<p>Primary neural stem cells isolated from brain specific knockout fetuses of dystroglycan were clonally expanded, and genotyping performed with knockout specific primers specifying intron 3. Western blot with β-DG antibody, and immunoflurescence staining with β-DG antibody were carried out to confirm successful knockout in clones. (A) Genotyping. (B) RT-PCR. (C) Western blot with β-DG antibody. (D and E) Anti-β-DG immunofluorescence staining of wildtype and knockout neural stem cells respectively. Abbreviations: DG, dystroglycan; DGKO, dystroglycan knockout. Scale bar in E: 50 µm.</p

Overexpression of LARGE in DG-deficient neural stem cells promoted laminin binding at the cell surface.

<p>Neural stem cells were cultured on fibronectin-coated chamber slides and infected with Ad-EGFP (A–D) and Ad-LARGE viruses (E–H). Two days after infection, laminin was added to the medium. The cells were washed and fixed 12 hrs later and immunostained with an antibody against laminin (red fluorescence, A, B, E, and F). (A, C, E, and G) Wildtype neural stem cells. (B, D, F, and H) DG-deficient neural stem cells. Abbreviations: DGKO, DG knockout; WT, wildtype. Scale bar in H: 50 µm (25 µm for inserts in A, B, E, and F).</p