Stability-Indicating High-Performance Thin-Layer Chromatographic Method for Simultaneous Estimation of the Active Pharmaceutical Ingredients Metolazone and Spironolactone

JPC – Journal of Planar Chromatography – Modern TLC - This work represents the validation of a stability-indicating thin-layer chromatographic technique for the simultaneous estimation...     

Dynamics of folding in semiflexible filaments

The dynamics of a single semiflexible filament under the action of a compressing force is simulated. We find that the filament folds asymmetrically with a folding length which depends only on the bending stiffness kappa and the applied force f. It is shown that this behavior can be attributed to the exponentially falling tension profile in the filament. While the folding time tau(0) depends on the initial configuration, the distance moved by the terminal point of the filament and the length of the fold scales as tau(1/2) at tau>tau(0) and is independent of the initial configuration.     

Biomimetic Explorations Towards the Bisorbicillinoids: Total Synthesis of Bisorbicillinol, Bisorbibutenolide, and Trichodimerol

Strikingly simple cascade dimerization sequences can be used to assemble the complex frameworks of bisorbicillinoids such as bisorbicillinol (1), bisorbibutenolide (2), and trichodimerol (3). The mechanistic facets of the biomimetic total syntheses of these bioactive natural products were also explored. Inspection of the unique molecular architecture of these compounds reveals that they are likely to be assembled in nature by a dimerization of two oxidized forms of sorbicillin.     

Die Raman-Spektren der Orthovanadate der Seltenen Erden

Raman Spectra of the Rare Earth Orthovanadate The laser-Raman spectra of the tetragonal rare earth orthovanadates of the type LnVO₄ (Ln = Pr to Lu) as well as those of ScVO₄ and YVO₄ has been recorded and interpreted with the aid of both, the site symmetry and the factor group analysis, using also IR data reported previously. The influence of the cations on the internal vibrations of the anion are discussed in detail.     

Darstellung und Eigenschaften einiger neuer Arsenat- und Vanadat-Halogen-Apatite

Preparation and Properties of Some New Arsenate and Vanadate Halogen Apatites The preparation of new apatite-like compounds of the composition Na₂Nd₂Pb₆(RO₄)₆X₂ (with R = As, V and X = Cl, Br and also R = P and X = Br) is reported. Crystallographic data for these as well as for the already known Na₂Nd₂Pb₆(PO₄)₆Cl₂ are determined from the corresponding X-ray powder diagrams. Also the infrared and Raman spectra were recorded and briefly discussed.     

Abschätzung mittlerer Schwingungsamplituden der Metall—Sauerstoff-Bindungen einiger Hexaoxometallate

Mean amplitudes of vibration of a series of hexaoxometalates have been estimated using an approximation method and recently reported spectroscopic data arising from the study of the respective lithium salts.     

Resonantly enhanced off-specular X-ray scattering from polymer/polymer interfaces<Superscript>⋆</Superscript>

We have used measurements of the absolute intensity of diffuse X-ray scattering to extract the interfacial tension of a buried polymer/polymer interface. Diffuse scattering was excited by an X-ray standing wave whose phase was adjusted to have a high intensity at the polymer/polymer interface and simultaneously a node at the polymer/air interface. This method permits the capillary-wave-induced roughness of the interface, and hence the interfacial tension, to be measured independently of the polymer/polymer interdiffusion.     

Real-time evolution of the distribution of nanoparticles in an ultrathin-polymer-film-based waveguide

We report a novel application of an ultrathin-polymer-film-based, resonance-enhanced x-ray waveguide as a real-time nanoprobe for elucidating dilute, yet disordered, gold nanoparticles embedded in the polymer matrix. This nanoprobe promises a sensitivity enhancement of several orders of magnitude, hence revealing in real time the lateral nanoparticle distribution with subnanometer spatial resolution. We observed that the motion of the nanoparticles is strongly anisotropic, with in-plane coalescence taking place more rapidly than out-of-plane diffusion, which can ultimately facilitate the formation of two-dimensional structures.     

$\delta$-pairing forces and collective pairing vibrations

The collective pairing Hamiltonian is obtained in the framework of the generator coordinate method in the Gaussian overlap approximation with a slightly modified BCS function used as a generator function. The collective variable , measuring the monopole moment of the pairing field, and the gauge transformation angle are chosen as generator coordinates. The vibrational ground states are calculated by diagonalisation of the collective pairing Hamiltonian in the harmonic-oscillator basis.Received: 28 April 2003, Revised: 1 October 2003, Published online: 18 June 2004PACS: 21.30.-x Nuclear forces - 21.60.Ev Collective models