99mTc-labelled human serum albumin: Chemical and electrochemical labelling methods

The labelling of human serum albumin /HSA/ with^99mTc has been investigated using a chemical method /stannous citrate/ and electrolytically generated tin/II/ ions. A comparative study of various chemical parameters and current intensities has been carried out in order to find the optimal conditions for labelling. The labelling yield was over 95%, for the chemical and electrolytical methods.     

Elimination of bremsstrahlung in activation analysis by the deflection of β-particles in a magnetic field

The structureless background at X-ray and low energy -ray region, resulting from bremsstrahlung due to the stopping of -radiations, causes serious problems in nuclear spectroscopy. In this study, in order to reduce the background and therefore to increase the sensitivity of the nuclear analytical technique and the number of elements observable, a methodology is developed to deflect the -particles by a magnetic field. The experimental setup consists of a permanent magnet /1 kG/, Ge/Li/ solid-state detector, and multichannel analyzer.     

Determination of trace elements in Na-bentonitic clay by INAA in Turkey

Instrumental neutron activation analysis was applied to the determination of trace elements in a Na-bentonitic clay. The irradiation was done in the Triga Mark II type reactor of ITU Nuclear Energy Institute. The sample was irradiated in two steps for short- and long- lived isotopes. After irradiation, spectra were taken using a germanium detector, multichannel analyzer Canberra System 100 and a fitting program called Sampo 90. The spectra of short-lived isotopes were analyzed to determine Al, Mg, Na, K, Ca, Ti elements and Mn, V trace elements. The spectra of long-lived isotopes were analyzed to determine Sc, Br, Sb, Cs, La, Ce, Sm, Yb, Hf, Pa, Np trace elements.     

Comparative EIS study of a paste electrode containing zinc powder in neutral and near neutral solutions

The corrosion and passivation of Zn powder particles dispersed in a paste electrode immersed in 0.5 M Na₂SO₄ and 5×10^–3 M Na₂HPO₄ solutions were studied mainly by electrochemical impedance spectroscopy. The role played by diffusion in the mechanism of anodic oxidation of zinc powder particles has been shown. It was demonstrated that the anodic reactionof Zn powder in neutral or near neutral media involves at least two adsorbed intermediates. By simulating the porous structure of the electrode, some information about porous nature of zinc electrode could be extracted. Electronic Publication     

Leaching of uranium with the H2O2-Na2SO4-H2SO4 (HSS) system and the efficiency of Acigol Lake water

The applicability of a new leaching method, the HSS (H₂O₂-Na₂SO₄-H₂SO₄) system, in the extraction of uranium from Saricaolu-Bergama Region low grade ore, and the efficiency of Acigol Lake (Denizli)-Turkey water as a natural source of Na₂SO₄ has been investigated. The effect of H₂SO₄ concentration, temperature, leaching time, H₂O₂ and Na₂SO₄ concentrations and the amount of Acigol Lake water on the extraction of uranium was examined. HSS was found suitable for the extraction of uranium from Saricaolu-Bergama Region samples and it was observed that the acid consumption could be decreased by adding Na₂SO₄.     

Peak area determination and energy dependence of gamma- and X-ray peak tailing

Two analytical shape functions representing the shapes of - and characteristic X-ray photopeak sides obtained with a Ge(Li) detector are described. The photopeak centroid is accurately determined by using these functions. Energy dependence of photopeak tailing at the lower energy side of the photopeaks are obtained by the least-squares fitting method. The present method can be used for the analysis of partly overlapped photopeaks, one side of which is well resolved, with a sufficient accuracy.     

NMR spectroscopy of organophosphorus compounds II: Stereochemistry of [1-(2H-azirin-2-yl)alkyl]phosphonates

Summary The conformation and relative configuration of [1-(2H-azirin-2-yl)alkyl]phosphonates (2) has been established by thorough investigation of some characteristic representatives of the series by¹H,¹³C,¹⁵N, and³¹P NMR spectroscopy. It is shown that the chemical shift of the proton located to the phosphonate group can be used as a criterion for the discrimination and stereochemical assignment of diastereoisomers. NMR spectroscopic features of the compounds are discussed in terms of structural relationships.Dedicated to Univ.-Prof. Dr.K. Schlögl with the best wishes to his 70^th birthday     

On input/output stabilization of singular integrodifferential systems

In this paper we consider a class of systems described by singular integrodifferential equations. This type of systems appear, for example, in the modeling of certain aeroelastic control problems. We study these systems in frequency domain framework and show the existence of finite-dimensional stabilizing controllers. An algorithmic procedure is outlined for the construction of such controllers. In order to illustrate the numerical aspects of this algorithm, we present an example involving the classical Theodorsen model of an airfoil, which fits in the class of systems considered here.This work was supported in part by the National Science Foundation under Grants DMS-8907019 and MSS-9203418.     

On the interpretation of random forces derived by projection operators

We study the derivation of a Langevin equation from a microscopic basis in order to elucidate the nature of the random force. We arrive at the conclusion that the consistent interpretation of the microscopic Langevin equation in terms of a stochastic differential equation (SDE) is according to I o rules. In addition, the random force is in general not Gaussian, and it is hence not completely characterized by its second moments.     

Measurement of L&agr; and Lß X-ray fluorescence cross sections in Er, Ta, W and Au by 16.896–59.543 keV photons

La and Lb X-ray fluorescence cross sections in Er, Ta, W and Au at excitation energies of 16.896, 22.581, 25.770, 32.890, 38.184, 43.949, 50.214 and 59.5 keV were investigated. Measurements were made using a low energy Si(Li) detector coupled to a model 4096 computerized multi-channel analyser. The experimental results were compared with the theoretically calculated values of L X-rays fluorescence cross sections and other experimental results. Good agreement was observed between experimental and theoretical values.