Application of Texture Analysis technique in formulation development of lyophilized orally disintegrating tablets containing mannitol, polyvinylpyrrolidone and amino acids

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Orally disintegrating tablets (ODTs) attract a great attention as this easy swallowing dosage form often improves patient compliance. In the current work, orally disintegrating tablets comprising mannitol, polyvinylpyrrolidone (PVP) and an amino acid (alanine, glycine or serine) with various PVP-to-amino acid ratios were formulated. The combination of mannitol and an amino acid was aimed to use the advantages of mannitol, the matrix-supporting and disintegration agent, and to reduce the total amount of sugar/polyol in tablets. Tablets were manufactured by freeze-drying and their properties (appearance, internal structure, disintegration, mechanical and texture properties, moisture uptake, shrinkage, thermal properties) were assessed. In the work, great emphasis was placed on illustrating the applicability of the Texture Analysis of the freeze-dried cakes directly in vials in formulation development. The results show that the appearance, mechanical properties, disintegration and shrinkage of the freeze-dried ODTs depend significantly on the excipient composition with PVP playing the leading role. Partial mannitol replacement with an amino acid has a limited impact on the tablet properties. The presence of an amino acid also has no impact on the PVP-mannitol interaction. The mechanical and texture properties of freeze-dried ODTs depend non-linearly on the PVP content. The transition between the different types of textures occurs in a narrow range of PVP concentrations regardless of the type of amino acid in a formulation. The non-linear effect of PVP on various tablet properties should be taken into account when designing ODT formulations as it can compromise the robustness of the manufacturing process

99 cent: Price Points in E-Commerce

Basu (2006) argues that the prevalence of 99 cent prices in shops can be explained with rational consumers who disregard the rightmost digits of the price. This bounded rational behaviour leads to a Bertrand equi- librium with positive markups. We use data from an Austrian price com- parison site and find results highly compatible with Basu's theory. We can show that price points - in particular prices ending in 9 - are preva- lent and have significant impact on consumer demand. Moreover, these price points are sticky; neither the price-setter itself wants to change them neither the rivals do underbid these prices, if they represent the cheapest price on the market.e-commerce, price comparison, price policy

99 cent: Price points in e-commerce

Basu (2006) argues that the prevalence of 99 cent prices in shops can be explained with rational consumers who disregard the rightmost digits of the price. This bounded rational behaviour leads to a Bertrand equilibrium with positive markups. We use data from an Austrian price comparison site and find results highly compatible with Basu's theory. We can show that price points - in particular prices ending in 9 - are prevalent and have significant impact on consumer demand. Moreover, these price points are sticky; neither the price-setter itself wants to change them neither the rivals do underbid these prices, if they represent the cheapest price on the market. --Competitive Behaviour,Pricing Behaviour,E-Commerce,Pricing in the Nines,Focal Pricing

Excitation intensity dependence of photoluminescence spectra of SiGe quantum dots grown on prepatterned Si substrates: Evidence for biexcitonic transition

The pumping intensity (I) dependence of the photoluminescence (PL) spectra of perfectly laterally two-dimensionally ordered SiGe quantum dots on Si(001) substrates was studied. The PL results from recombinations of holes localized in the SiGe quantum dots and electrons localized due to the strain field in the surrounding Si matrix. The analysis of the spectra revealed several distinct bands, attributed to phonon-assisted recombination and no-phonon recombination of the excitonic ground state and of the excited excitonic states, which all exhibit a linear I dependence of the PL intensity. At approximately I>3W/cm^2, additional bands with a nearly quadratic I dependence appear in the PL spectra, resulting from biexcitonic transitions. These emerging PL contributions shift the composite no-phonon PL band of the SiGe quantum dots to higher energies. The experimentally obtained energies of the no-phonon transitions are in good agreement with the exciton and biexciton energies calculated using the envelope function approximation and the configuration interaction method

Entry, exit, and pricing strategies at online price-comparison sites : do price markups fall by themselves, or is competition crucial?

Immer mehr Menschen gehen beim Surfen im World Wide Web auf Einkaufstour. Dabei geben Preisvergleichsseiten oftmals hilfreiche Tipps, wo das gesuchte Produkt am günstigsten zu haben ist. Dass sich ein Vergleich lohnt, zeigt eine Studie des Zentrums für Europäische Wirtschaftsforschung (ZEW) Mannheim und der Universität Linz. Die Studie kommt zu dem Ergebnis, dass bereits zehn zusätzliche Anbieter des gleichen Produkts den Preisaufschlag des günstigsten Anbieters um 1,7 Prozentpunkte verringern

High-field muSR studies of superconducting and magnetic correlations in cuprates above Tc

The advent of high transverse-field muon spin rotation (TF-muSR) has led to recent muSR investigations of the magnetic-field response of cuprates above the superconducting transition temperature T_c. Here the results of such experiments on hole-doped cuprates are reviewed. Although these investigations are currently ongoing, it is clear that the effects of high field on the internal magnetic field distribution of these materials is dependent upon a competition between superconductivity and magnetism. In La_{2-x}Sr_xCuO_4 the response to the external field above Tc is dominated by heterogeneous spin magnetism. However, the magnetism that dominates the observed inhomogeneous line broadening below x ~ 0.19 is overwhelmed by the emergence of a completely different kind of magnetism in the heavily overdoped regime. The origin of the magnetism above x ~ 0.19 is currently unknown, but its presence hints at a competition between superconductivity and magnetism that is reminiscent of the underdoped regime. In contrast, the width of the internal field distribution of underdoped YBa_2Cu_3O_y above Tc is observed to track Tc and the density of superconducting carriers. This observation suggests that the magnetic response above Tc is not dominated by electronic moments, but rather inhomogeneous fluctuating superconductivity.Comment: 28 pages, 11 figures, 104 reference

Comment on "Zeeman-Driven Lifshitz Transition: A Model for the Experimentally Observed Fermi-Surface Reconstruction in YbRh2Si2"

In Phys. Rev. Lett. 106, 137002 (2011), A. Hackl and M. Vojta have proposed to explain the quantum critical behavior of YbRh2Si2 in terms of a Zeeman-induced Lifshitz transition of an electronic band whose width is about 6 orders of magnitude smaller than that of conventional metals. Here, we note that the ultra-narrowness of the proposed band, as well as the proposed scenario per se, lead to properties which are qualitatively inconsistent with the salient features observed in YbRh2Si2 near its quantum critical point.Comment: 3 page

Electron-boson glue function derived from electronic Raman scattering

Raman scattering cross sections depend on photon polarization. In the cuprates nodal and antinodal directions are weighted more strongly in $B_{2g}$ and $B_{1g}$ symmetry, respectively. On the other hand in angle-resolved photoemission spectroscopy (ARPES), electronic properties are measured along well-defined directions in momentum space rather than their weighted averages. In contrast, the optical conductivity involves a momentum average over the entire Brillouin zone. Newly measured Raman response data on high-quality Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ single crystals up to high energies have been inverted using a modified maximum entropy inversion technique to extract from $B_{1g}$ and $B_{2g}$ Raman data corresponding electron-boson spectral densities (glue) are compared to the results obtained with known ARPES and optical inversions. We find that the $B_{2g}$ spectrum agrees qualitatively with nodal direction ARPES while the $B_{1g}$ looks more like the optical spectrum. A large peak around $30 - 40\,$meV in $B_{1g}$, much less prominent in $B_{2g}$, is taken as support for the importance of $(\pi,\pi)$ scattering at this frequency.Comment: 7 pages, 3 figure

Market structure and market performance in E-commerce

We investigate the effect of market structure on market performance in the market for consumer electronics. We exploit product life cycle information to build an instrumental variable for the number of firms in a market, a variable which hitherto had to be treated as exogenous in comparable studies on seller-behavior in e-commerce. We combine data from Austria´s largest online site for price comparisons with retail data on wholesale prices provided by a major hardware producer for consumer electronics. We observe input prices of firms, and all their moves in the entry and the pricing game. Using this information for 70 digital cameras, we generate instrumenting is particularly important for estimating the effect of competition on the markup of the price leader

Topological phase transition in a RNA model in the de Gennes regime

We study a simplified model of the RNA molecule proposed by G. Vernizzi, H. Orland and A. Zee in the regime of strong concentration of positive ions in solution. The model considers a flexible chain of equal bases that can pairwise interact with any other one along the chain, while preserving the property of saturation of the interactions. In the regime considered, we observe the emergence of a critical temperature T_c separating two phases that can be characterized by the topology of the predominant configurations: in the large temperature regime, the dominant configurations of the molecule have very large genera (of the order of the size of the molecule), corresponding to a complex topology, whereas in the opposite regime of low temperatures, the dominant configurations are simple and have the topology of a sphere. We determine that this topological phase transition is of first order and provide an analytic expression for T_c. The regime studied for this model exhibits analogies with that for the dense polymer systems studied by de GennesComment: 15 pages, 4 figure