Alumina nanotubes containing lithium of high ion mobility

We revealed the first example of a crystalline lithium aluminate nanotube with thermal stability prepared by a surfactant-driven hydrothermal procedure. The obtained nanotube showed an interesting structure unknown thus far for oxide nanotubes such as cylindrical bundles of lithium aluminate subnanotubules. These novel nanotubules had walls of crystalline lithium aluminate with a honeycomblike Al-O wall-network surrounding a central lithium core that forms a linear array of atoms and could be a promising solid ion conducting material.     

Characterization of the allosteric inhibition of a protein-protein interaction by mass spectrometry

The allosteric inhibition of the lymphocyte function associated antigen-1/intercellullar adhesion molecule (LFA-1/ICAM-1) interaction, by a class of small molecules, is characterized by a battery of mass spectrometric techniques. Binding of hydantoins to the I domain of LFA-1 is observed by size exclusion chromatography/mass spectrometry (SEC/MS) and by direct electrospray ionization mass spectrometry (ESI/MS). A photoactive hydantoin analog specifically labels an amino acid residue of LFA-1 I domain. Competition with this photoaffinity labeling by a panel of inhibitors is correlated with their Kd's for inhibition of the LFA-1/ICAM interaction. Alterations to the tertiary structure of LFA-1 I domain, upon compound binding, are inferred from perturbation in the ESI mass spectrum of the polypeptide's charge state distribution and by an altered level of nonspecific multimer formation. The results demonstrate specific, stoichiometric, reversible binding of the hydantoins to LFA-1. They further show correlation of this binding with activity and indicate alterations in the polypeptide's tertiary structure, on hydantoin binding, consistent with the proposed mechanism for inhibition of the protein-protein interaction.     

Crystal and molecular structure of dichlorofluoroacetamide

The crystal structure of dichlorofluoroacetamide has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁ /c and have the unit-cell parametersa = 10.207(4),b = 5.729(2),c = 9.971(4) Å, = 105.21(8) °, andD _x = 1.72 g cm^-3. The structural refinement gave a finalR factor of 0.067 from 440 observed reflections. The compound has nearly equal disorder of the -Cl₂F moiety about the C-C bond axis with occupancy factors of the two fragments being 0.48 and 0.52.     

2. Spezielle Produkte und Anwendungsgebiete

Referate

2 Spezielle Produkte und Anwendungsgebiete2.4 Umweltrelevante Matrices     

Vibrational relaxation of ozone by para and normal hydrogen

The relaxation of O₃(001) by p- and n-H₂ was measured over the temperature range 167–424 K. n-H₂ quenched ozone more efficiently, with the difference between rate constants increasing with temperature. These observations are explained by a near-resonant V—R process, in agreement with the Sharma—Brau theory.     

An efficient and accurate parallel algorithm for the singular value problem of bidiagonal matrices

Summary. In this paper we propose an algorithm based on Laguerre's iteration, rank two divide-and-conquer technique and a hybrid strategy for computing singular values of bidiagonal matrices. The algorithm is fully parallel in nature and evaluates singular values to tiny relative error if necessary. It is competitive with QR algorithm in serial mode in speed and advantageous in computing partial singular values. Error analysis and numerical results are presented. Received March 15, 1993 / Revised version received June 7, 1994     

Naphthaceno[5,6-cd]-1,2-dithiole,C18H10S2

C₁₈H₁₀S₂,M=290.34, monoclinic,P2₁,a=20.556(5),b=15.843(3),c=3.963(1) Å,β=92.79(2)° at 18°C,Z=4,D _x =1.496 g cm^?3,μ(Cu Kα)=3.53 mm^?1. Full-matrix least-squares refinement resulted in a final conventionalR value of 0.036 for 2030 observed reflections. The average C-S bond distance is 1.747(16) Å, the S-S bond length is 2.074(1) Å. The torsion angles at the disulfide group are close to zero, at 3.5 and 0.8°. The carbon frameworks are nearly planar, and closely approximate symmetrymmm. Bond distances are comparable with those in related molecules.