Densitometric and Videodensitometric TLC Determination of Timolol and Betaxolol in Ophthalmic Solutions

JPC – Journal of Planar Chromatography – Modern TLC - A new, accurate, rapid TLC method has been established for determination of timolol maleate (Timohexal 0.1%, Timoptic 0.25%) and...     

Determination of Fe(II) and Zn(II) in Vitrum Prenatal by Ion Chromatography (IC). Comparison with Classical and Derivative Spectrophotometry (D0, D1, and D2) with Metrian,Metriap, Metriarez-γ, and Metidarez-β Dyes and with Atomic Absorption Spectrometry

JPC – Journal of Planar Chromatography – Modern TLC - 3-Mercapto-5-(2′-hydroxynaphthylazo-1′)-1,2,4-triazole (metrian);...     

Study of heating effect and acoustic properties of dextran stabilized magnetic fluid

This paper presents acoustic properties of water-based biocompatible fluids in which magnetite particles (Fe₃O₄) were coated with two layers of surfactants: sodium oleate and dextran. The attenuation coefficient of ultrasonic wave measurements shows good structural stability of the fluid under the influence of a magnetic field. Hyperthermic tests proved that the magnetic fluid is suitable for therapeutic use as an agent which can release thermal energy (hyperthermia).     

Application of a simple peak shape function for the evaluation of gamma and X-ray spectra

The computational method for the rapid evaluation of gamma and X-ray spectra observed by semiconductor detectors in radiometric analysis in presented using a simple peak shape function. The computer programme includes a minimizing routine based on the modified Newton-Raphson method giving a minimized vector of the parameters more rapidly than the conventional approach. The spectra of some gamma-ray emitting fission products and X-ray spectra excited by radioisotopes of materials from copper ore processing were studied. It was found that the simple Gaussian peak function gives the results equivalent to the total peak area method.     

Global phase diagram of the fractional quantum Hall effect arising from repulsive three-body interactions

The model of fermions in a magnetic field interacting via a purely three-body repulsive interaction has attracted interest because it produces, in the limit of short range interaction, the Pfaffian state with non-Abelian excitations. We show that this is part of a rich phase diagram containing a host of fractional quantum Hall states, a composite fermion Fermi sea, and a pairing transition. This is entirely unexpected, because the appearance of composite fermions and fractional quantum Hall effect is ordinarily thought to be a result of strong two-body repulsion. Recent breakthroughs in ultracold atoms have facilitated the realization of such a system, where this physics can be tested.     

Development of a three-dimensional topographic map display for capillary electrophoresis/mass spectrometry with an ion trap/reflectron time-of-flight mass spectrometer detector: Applications to tryptic digests of isoforms of myelin basic protein

A three-dimensional (3-D) contour map format has been developed to display the large amount of data continuously collected throughout an on-line capillary separation using an ion trap storage/reflectron time-of-flight detector (IT/reTOF). The resulting data are displayed on a single computer screen with a mass-to-charge ratio value-elution time-intensity representation. The intensity of various components is represented by 16 different colors so that the mass-to-charge ratio value, the elution time, and the intensity can be conveniently determined for each component. In addition, the mass spectrum and total ion chromatogram or total ion electropherogram (TIE) are shown on the same screen as the 3-D map that enables the correlation of a single spot in the 3-D map to the peaks in the TIE and the corresponding mass spectrum. The 3-D map has been used to identify various posttranslational modification sites of bovine myelin basic protein charge isomers, where the datafiles of tryptic digests of proteins analyzed by capillary electrophoresis/mass spectrometry were processed by this software and a comparison could be performed among the isoforms. The feature of in-screen integration over both the separation domain and the mass domain makes the acquisition of the selected ion chromatogram very convenient and greatly improves the ability to detect modified components present in low amounts.     

Determination of counting losses and pile-up rejection in ionizing radiation spectrometry

The spectrometric system for ionizing radiation measurement with pile-up rejection and counting losses correction has been described. The results for HpGe, Ge(Li), Si(Li) and surface barrier detectors have been presented. The total count rate ranged from 500 to 10⁵ cps and different radioisotopes have been used. The counting losses correction accuracy has been within ±1% with tenfold reduction of background from pile-up pulses. The possibility of the system application for radiation intensity measurement of the mixture of short- and longlived radioisotopes has been discussed.     

Relative Entropy in Determining Degressive Proportional Allocations

The principle of degressively proportional apportionment of goods, being a compromise between equality and proportionality, facilitates the application of many different allocation rules. Agents with smaller entitlements are more interested in an allocation that is as close to equality as possible, while those with greater entitlements prefer an allocation as close to proportionality as possible. Using relative entropy to quantify the inequity of allocation, this paper indicates an allocation that neutralizes these two contradictory approaches by symmetrizing the inequities perceived by the smallest and largest agents participating in the apportionment. First, based on some selected properties, the set of potential allocation rules was reduced to those generated by power functions. Then, the existence of the power function whose exponent is determined so as to generate the allocation that symmetrizes the relative entropy with respect to equal and proportional allocations was shown. As a result, all agents of the apportionment are more inclined to accept the proposed allocation regardless of the size of their entitlements. The exponent found in this way shows the significant relationship between the problem under study and the well-known Theil indices of inequality. The problem may also be seen from this viewpoint.     

Dose-rate effect in the model of semi-localized transitions (SLT)

The model of semi-localized transitions (SLT) unifies two standard models of thermoluminescence (TL) and optically stimulated luminescence (OSL) kinetics – the simple trap model (STM) and the model of localized transitions (LT). SLT equations were previously formulated for the heating stage of TL. This paper presents SLT equations for the excitation and fast relaxation stages. Exemplary calculations were performed to show the occurrence of dose-rate effect – previously found in STM. It is shown that the dose-rate effect occurs for both – localized and delocalized TL glow peaks.