Viscoelastic characterization of compacted pharmaceutical excipient materials by analysis of frequency-dependent mechanical relaxation processes

A newly developed method for determining the frequency-dependent complex Young's modulus was employed to analyze the mechanical response of compacted microcrystalline cellulose, sorbitol, ethyl cellulose and starch for frequencies up to 20 kHz. A Debye-like relaxation was observed in all the studied pharmaceutical excipient materials and a comparison with corresponding dielectric spectroscopy data was made. The location in frequency of the relaxation peak was shown to correlate to the measured tensile strength of the tablets, and the relaxation was interpreted as the vibrational response of the interparticle hydrogen and van der Waals bindings in the tablets. Further, the measured relaxation strength, holding information about the energy loss involved in the relaxation processes, showed that the weakest material in terms of tensile strength, starch, is the material among the four tested ones that is able to absorb the most energy within its structure when exposed to external perturbations inducing vibrations in the studied frequency range. The results indicate that mechanical relaxation analysis performed over relatively broad frequency ranges should be useful for predicting material properties of importance for the functionality of a material in applications such as, e.g., drug delivery, drug storage and handling, and also for clarifying the origin of hitherto unexplained molecular processes.     

Isomorphic pairs of homogeneous functions and their morphisms

Summary. In this paper we determine all iseomorphic pairs (isomorphic pairs with monotonic, thus continuous isomorphisms) of continuous, strictly increasing, linearly homogeneous functions defined on cartesian squares I ² and J ² of intervals of positive numbers or on their restrictions or and or We prove that, if the iseomorphy is nontrivial, then each homogeneous function is a (weighted) geometric or power mean or a joint pair of such means. In functional equations terminology this means that all nontrivial continuous strictly increasing linearly homogeneous solutions G, H (with the continuous strictly monotonic F also unknown) of the equation on D _< or D _> are weighted geometric or power means, while on I ² they are joint pairs of weighted geometric means or of weighted power means.     

Vibrational multilevel quantum coherence due to anharmonic couplings in intermolecular hydrogen bonds

Femtosecond three-pulse photon-echo studies of acetic acid dimers in solution reveal multilevel coherence of O-H stretching excitations caused by the anharmonic coupling between the high-frequency stretching and low-frequency hydrogen-bond motions. We demonstrate for the first time that such multilevel coherence determines the nonexponential decay of the macroscopic O-H stretching polarization, whereas spectral diffusion processes play a minor role. The dephasing time of individual vibrational transitions contributing to the overall polarization is approximately 200 fs.     

A Paley-Wiener theorem for the spherical Laplace transform on causal symmetric spaces of rank 1

We formulate and prove a topological Paley-Wiener theorem for the normalized spherical Laplace transform defined on the rank 1 causal symmetric spaces , for .

     

Experimental evidence for a light and broad scalar resonance in D(+) --> pi(-)pi(+)pi(+) decay

From a sample of 1172 +/- 61 D(+)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)-->pi(-)pi(+)pi(+))/gamma(D(+)-->K-pi(+)pi(+)) = 0.0311 +/- 0.0018(+0.0016)(-0.0026). Using a coherent amplitude analysis to fit the Dalitz plot of these decays, we find strong evidence that a scalar resonance of mass 478(+24)(-23) +/- 17 MeV/c(2) and width 324(+42)(-40) +/- 21 MeV/c(2) accounts for approximately half of all decays.     

Horizon-less Spherically Symmetric Vacuum-Solutions in a Higgs Scalar-Tensor Theory of Gravity

The exact static and spherically symmetric solutions of the vacuum field equations for a Higgs Scalar-Tensor theory (HSTT) are derived in Schwarzschild coordinates. It is shown that in general there exists no Schwarzschild horizon and that the fields are only singular (as naked singularity) at the center (i.e. for the case of a point-particle). However, the Schwarzschild solution as in usual general relativity (GR) is obtained for the vanishing limit of Higgs field excitations.     

Almost hermitian structures with parallel torsion

The characteristic connection of an almost hermitian structure is a hermitian connection with totally skew-symmetric torsion. The case of parallel torsion in dimension 6 is of particular interest. In this work, we give a full classification of the algebraic types of the torsion form, and, on the basis of this, undertake a systematic investigation into the possible geometries. Numerous naturally reductive spaces are constructed and classified, and examples on nilmanifolds given.     

Evidence for N2N3N45 super coster kronig processes in metallic Nb,Mo, Ru and Rh

The 4p photoelectron spectra of metallic Nb, Mo, Ru and Rh have been recorded. By use of a deconvolution procedure it is shown that the 4p_{$\text{1}\text{2}$} spin-orbit component has a linewidth which significantly exceeds that of the 4p_{$\text{3}\text{2}$} component. This suggests that N₂N₃N₄₅ super Coster Kronig processes give a considerable contribution to the decay rata of the 4p_{$\text{1}\text{2}$} hole state.     

Formation of collisionless high-beta plasmas by odd-parity rotating magnetic fields

Odd-parity rotating magnetic fields (RMFo) applied to mirror-configuration plasmas have produced average electron energies exceeding 200 eV at line-averaged electron densities of approximately 10(12) cm-3. These plasmas, sustained for over 10(3)tauAlfven, have low Coulomb collisionality, vc* triple bond L/lambdaC approximately 10(-3), where lambdaC is the Coulomb scattering mean free path and L is the plasma's characteristic half length. Divertors allow reduction of the electron-neutral collision frequency to values where the RMFo coupling indicates full penetration of the RMFo to the major axis.