Formation of Iron Macro-Spheres in Plasma

In this paper the formation mechanism of iron macro-spheres in a plasma medium is dealt with, including the conditions under which such spheres are formed. The geometry of the spheres referred to above depends on the main technological parameters involved in the production of pores. Conditions under which pores occur within macro-spheres are also established. The radii of these pores are sensitive to the velocity distribution within the plasma jet section     

A Restudy of Direct Chelatometric Titration of Vanadium(IV) with N-Benzoyl-N-phenylhydroxylamine as Indicator

This paper restudies the method of direct chelatometric titration of V(IV) with N-benzoyl-N-phenylhydroxylamine (BPHA) as indicator. The indicator functions entirely differently from indicators hitherto used in chelatometry. The solution contains two independent systems – the indicator and the titrand-titrant system – without any color changing species. The BPHA-V(V) chelate once formed as the result of aerial oxidation constitutes the indicator system and does not react with EDTA. Its color therefore remains unchanged throughout titration. It is not a metallochromic indicator. Its function is that of color-screening. The color of the titrant system deepens during titration, but does not change. The end-point is indicated by one color completely covering up the other. Hence, this method is of purely empirical nature.Received July 5, 2002; accepted February 11, 2003 Published online July 16, 2003     

The Role of Carnitine Acyltransferases in the Maintenance of Cell Function

Summary. Carnitine acyltransferases catalyse equilibria between acyl-CoA esters and the respective acylcarnitines. Therefore, they act not only as pathway enzymes, but also as modulators of acyl-CoA concentrations within individual sub-cellular compartments. Because acyl-CoA esters are potent biologically active metabolites, carnitine acyltransferase activities are potentially able to affect a diverse range of physiological processes, ranging from insulin secretion, to appetite control, and insulin sensitivity of tissues. The distinctive subcellular distributions of the different types of carnitine acyltransferases also enables them to participate in the transfer of acyl moieties across intracellular membranes, and of particular acylcarnitine esters across the plasma membrane and into the plasma. Pharmacological strategies that make use of these properties to improve cell function are discussed.     

Syntheses and Properties of Two Heterocyclically Substituted Hypericin Derivatives: 10,11-Dibenzothiazolyl-10,11-didemethylhypericin and 10,11-Dibenzoxazolyl-10,11-didemethylhypericin

Summary. The syntheses of the two heterocyclically substituted title hypericin derivatives were achieved starting either from 6-benzothiazolyl-tri-O-methyl-6-demethylemodin or 6-benzoxazolyl-tri-O-methyl-6-demethylemodin. The use of microwave assisted synthesis for the preparation of these anthraquinone synthons and the chemical as well as photochemical properties of the corresponding unique hypericin derivatives, which might constitute new photodynamic therapy agents, are reported. The tautomeric and stereochemical aspects of these hypericin derivatives were investigated by means of semiempirical calculations (AM1).     

Silochroms as adsorbents and supports in liquid chromatography

The use of macroporous silica gels, silochroms, with homogeneous geometrical structure as adsorbents and supports for liquid stationary phases in liquid chromatography is described.

The selectivity of separation and retention volumes of silochroms depend strongly on the degree of hydroxylation of the surface and on the nature of the mobile phase. In optimizing the parameters, rapid and complete separation of strongly polar isomers and biological active substances and drugs is obtained.

The dependence of retention volumes and column efficiency on the amount of liquid phase, covered on silochrom, has been investigated.     

Investigation of the species-specific degradation behaviour of methylmercury and ethylmercury under microwave irradiation

The degradation behaviour of methylmercury (MeHg) under microwave irradiation is investigated, as is the (different) degradation behaviour of ethylmercury (EtHg) under similar irradiation. A simple and highly sensitive SPME-GC-pyrolysis-AFS system was used to analyse the aqueous MeHg and EtHg standard solutions after derivatization with sodium tetraphenylborate (NaBPh₄). Samples were irradiated in a microwave digester at microwave powers ranging from 20 to 160 W for durations of 2 to 10 min. The different tolerances towards microwave treatment of the two organomercury species were evident. Practically no degradation was experienced for MeHg for up to 8 minutes of irradiation at 120 W or for up to 4 minutes at 160 W. Significant analyte loss was observed for EtHg after 2 minutes at 40 W of microwave power. Awarded a Poster Prize on the occasion of the European Winter Conference on Plasma Spectrochemistry, February 2005, Budapest, Hungary     

Electrochromic and structural characteristics of mesoporous WO<Subscript>3</Subscript> films prepared by a sol-gel method

The preparation of electrochromic films of mesoporous tungsten trioxide from tungstic acid and tungstic hexaethoxide precursors with the addition of an organic stabiliser via a sol-gel method is reported. These films have been structurally characterised and both the film morphology and crystalline composition of the films were found to be significantly dependent on the temperature at which the films were annealed and upon the choice of precursor. Films annealed at lower temperatures consisted of amorphous and hexagonal tungsten trioxide, whereas films annealed above 500 °C comprised solely of monoclinic WO₃. The electrochromic activity of the films was found to be equally dependent on method of preparation, and both the composition and the structure of the WO₃ films were shown to clearly influence the colouration efficiency of the films.Dedicated to Zbigniew Galus on the occasion of his 70^th birthday.     

Estimation of isoelectric points of human plasma proteins employing capillary isoelectric focusing and peptide isoelectric point markers

Synthetic UV-detectable peptide pI markers were used to estimate isoelectric point (pI) values of proteins separated by capillary isoelectric focusing (CIEF) followed by cathodic mobilization in the absence of denaturing agents. The pI calculation and quantitative analysis of purified proteins showed the feasibility of these peptides as pI markers and internal standards in CIEF separation of proteins. Estimation of pI values of major proteins in human plasma was performed using the peptide pI markers, and the values were compared with those previously obtained by gel isoelectric focusing (IEF). Sera of immunoglobulin G (IgG) myeloma patients, which showed characteristic peaks of myeloma IgG in their CIEF patterns, were also subjected to the analysis and the pI values of the myeloma proteins have been estimated.     

Occurrence of synergism between phospholipids and prostaglandins in extracts of some tissues of commercial squid

The phospholipid compositions, prostaglandin-like activities, and ratios of prostaglandins of groups of E, F and A in prostaglandin extracts of some organs of two species of commercial squid have been investigated.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Division of the Russian Academy of Sciences, Russia, 69022, Vladivostok, Prosp. Stoletiya Vladivostoka, 159. Translated from Khimiya Priodnykh Soedinenii, No. 5,pp.693–696, September–October, 1996. Original articel submitted June 19, 1995     

Neighboring amide group participation in ester aminolysis in aprotic solvents

The piperidinolysis of 8-quinolyl-, p-nitrophenyl-, o-, and p-piperidinocarbonylphenyl acetates in acetonitrile and in chlorobenzene was studied at 25°C. The strictly second order kinetic behaviour and the weaks solvent-dependence of the rate of the reaction of o-piperidinocarbonylphenyl acetate indicate anchimeric assistance by the o-amide group, and support the suggestion that amide groups of hydrophobic enzyme active sites may act as general base catalysts.

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