Comparison between Lc/Uv and Gc/Fid techniques in determining N,NDimethylacetamide(Dma) in diacerein

Objectives: The aim of this work was the quantitative determination of N,N-Dimethylacetamide (DMA) as crystallization solvent in samples of Diacerein. DMA is commonly used as a solvent in the chemical, agricultural and pharmaceutical industries. However, in order to ensure product quality and to protect patients from the potentially toxic properties, the substances used as active ingredients in therapeutic drugs should not contain high levels of residual solvents. Methods: LC is commonly used in the pharmaceutical industry to check DMA in pharmaceutical products, but in this work we were interested in validating and comparing LC/UV and GC/FID techniques for determining the presence of DMA in Diacerein Results: Both methods showed good linearity, precision and accuracy with comparable LOD and LOQ. Conclusion: The GC method, however, since it uses DMSO as an internal standard, has higher analytical versatility, thus allowing the qualitative and quantitative determination of DMA at lower levels than those obtained with LC

Spartan Daily, October 12, 1953

Volume 42, Issue 14https://scholarworks.sjsu.edu/spartandaily/11920/thumbnail.jp

Spartan Daily, June 4, 1953

Volume 41, Issue 159https://scholarworks.sjsu.edu/spartandaily/11905/thumbnail.jp

Spartan Daily, June 7, 1954

Volume 42, Issue 155https://scholarworks.sjsu.edu/spartandaily/12049/thumbnail.jp

Fluids confined in wedges and by edges: Virial series for the line-thermodynamic properties of hard spheres

This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In particular, the well known hard sphere fluid, which was not studied in this framework so far, is analyzed under confinement and its thermodynamic properties are analytically studied up to order two in the density. Furthermore, the analysis is extended to the confinement produced by a corrugated wall. These results rely on the obtained analytic expression for the second cluster integral of the confined hard sphere system as a function of the opening dihedral angle 0 < β < 2π. It enables a unified approach to both wedges and edges.Fil: Urrutia, Ignacio. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The Cowl - v.52 - n.19 - Sep 28, 1988

The Cowl - student newspaper of Providence College. Vol 52 - No. 19 - September 28, 1988. 16 pages

Testing against stochastic trend and seasonality in the presence of unattended breaks and unit roots

This paper considers the problem of testing against stochastic trend and seasonality in the presence of structural breaks and unit roots at frequencies other than those directly under test, which we term unattended breaks and unattended unit roots respectively. We show that under unattended breaks the true size of the Kwiatkowski et. al. (1992) [KPSS] test at frequency zero and the Canova and Hansen (1995) [CH] test at the seasonal frequencies fall well below the nominal level under the null with an associated, often very dramatic, loss of power under the alternative. We demonstrate that a simple modification of the statistics can recover the usual limiting distribution appropriate to the case where there are no breaks, provided unit roots do not exist at any of the unattended frequencies. Where unattended unit roots occur we show that the above statistics converge in probability to zero under the null. However, computing the KPSS and CH statistics after pre-filtering the data is simultaneously efficacious against both unattended breaks and unattended unit roots, in the sense that the statistics retain their usual pivotal limiting null distributions appropriate to the case where neither occurs. The case where breaks may potentially occur at all frequencies is also discussed. The practical relevance of the theoretical contribution of the paper is illustrated through a number of empirical examples.stationarity tests, structural breaks, pre-filtering, unattended unit roots

The Cowl - v.38 - n.3 - Sep 15, 1983

The Cowl - student newspaper of Providence College. Vol 38 - No. 3 - September 15, 1983. 16 pages