Authors:R. Marinkovic-Neducin, E. Kiss, T. Cukic, and D. Obadovic
The purified bentonite parent clay, fraction ≤; 2 mm of montmorillonite type, has been pillared by various polyhydroxy cations,
Al, AlFe and AlCu, using conventional pillaring methods. The thermal behavior of PILCs was investigated by combination of
X-ray diffraction (XRD), thermal analysis (DTA, TG) and low temperature N2 adsorption/desorption (LTNA). Thermal stability
of Al-, AlFe- and AlCu-PILC samples was estimated after isothermal pretreatment in static air on the temperatures 300, 500,
600 and 900C. Crucial structural changes were not registered up to 600C, but the fine changes in interlayer surrounding
and porous/microporous structure being obvious at lower temperatures, depending on the nature of the second pillaring ion.
AlFe-PILC showed higher thermal stability of the texture, the AlCu-PILC having lower values and lower thermal stability concerning
both overall texture and micropore surface and volume. Poorer thermal stability of AlCu-PILC sample at higher temperatures
was confirmed, the presence of Cu in the system contributing to complete destruction of aluminum silicate structure, by 'extracting'
aluminum in stabile spinel form.
Authors:D. Kiss, R. Zelkó, Cs. Novák, and Zs. Éhen
The purpose of the present
work was to study the compatibility of metronidazole with different pharmaceutical
excipients (hydroxypropyl methylcellulose, poly(ethylene oxide), microcrystalline
cellulose, dicalcium phosphate dihydrate, and anhydrous dicalcium phosphate)
using differential scanning calorimetry and diffuse reflectance spectroscopy.
Dicalcium phosphate dihydrate was the only excipient that showed interaction
with metronidazole even before storage. Changes referring to a possible transition
to dihydrate form were observed in the thermal curves of anhydrous dicalcium
phosphate after four weeks of storage. Although dicalcium phosphate dihydrate
can be replaced by the anhydrous form in pharmaceutical formulations, the
observed transition might negatively influence the stability of dosage forms.
Authors:E. Koltay, I. Rajta, Zs. Rajta, I. Uzonyi, J.R. Morales, and Á. Kiss
Aerosol samples collected around the Chilean site Lonquimay during major volcanic activities in January 1989 have been subjected to microPIXE measurements of 1 mm lateral resolution in the Debrecen Institute. Elemental concentrations relative to calcium have been determined for Al, Si, P, S, K, Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Ba in 187 individual aerosol particles with the particle sizes between 15 mm and 1 mm. On the basis of a cluster analysis performed on the data set we defined eight clusters. Scatter plots for selected pairs of elements as Si/Al, K/Si, S/Cl, and Al/S elemental ratios that are considered as signatures characterizing types and mechanisms in volcanic eruption - have been compared with published data available in the literature for various volcanic sites.
Authors:J. Németh, B. Jakab, R. Józsa, T. Hollósy, A. Tamás, A. Lubics, I. Lengvári, P. Kiss, Zs. Oberritter, B. Horváth, Z. Szilvássy, and D. Reglődi
Pituitary adenylate cyclase activating polypeptide (PACAP) is a widely distributed neuropeptide that has two molecular forms
with 38 and 27 amino acid residues. The aim of the present study was to develop a new, highly specific PACAP-27 assay to investigate
the quantitative distribution of PACAP-27 in the central nervous system of various vertebrate species applying the same technical
and experimental conditions. Our results show that the antiserum used turned to be PACAP-27 specific. The average ID50 value was 51.5±3.6 fmol/ml and the detection limit was 2 fmol/ml. PACAP-27 immunoreactivity was present in the examined brain
areas, with highest concentration in the rat diencephalon and telencephalon. Swine and pigeon brain also contained significant
amount of PACAP-27. Our results confirm the previously described data showing that PACAP-38 is the dominant form of PACAP
in vertebrates, since PACAP-38 levels exceeded those of PACAP-27 in all examined brain areas. Furthermore, our study describes
for the first time, the comparative quantitative distribution of PACAP-27 and-38 in the swine and pigeon brain.