Measurement of the in-medium K0 inclusive cross section in pi(-) -induced reactions at 1.15 GeV/c.

The K0 meson production by pi(-) mesons of 1.15 GeV/c momentum on C, Al, Cu, Sn, and Pb nuclear targets was measured with the FOPI spectrometer at the Schwer-Ionen-Synchrotron accelerator of GSI. Inclusive production cross sections and the momentum distributions of K0 mesons are compared to scaled elementary production cross sections and to predictions of theoretical models describing the in-medium production of kaons. The data represent a new reference for those models, which are widely used for interpretation of the strangeness production in heavy-ion collisions. The presented results demonstrate the sensitivity of the kaon production to the reaction amplitudes inside nuclei and point to the existence of a repulsive KN potential of 20+/-5 MeV at normal nuclear matter density.

Growth inhibition mode of action of selected benzoic acid derivatives against the yeast Pichia anomala.

Three benzoic acid derivatives (zinc p-iodobenzoate, zinc p-hydroxybenzoate, and zinc p-aminobenzoate) were synthesized and tested chemically and microbiologically in order to explain their mode of action against the yeast Pichia anomala. The yeast strains were cultivated in batch culture of chemically defined minimal medium (control) and with the addition of the studied compound at concentrations of 0.103 to 0.166% (wt/vol). The growth of microorganisms, H+ concentration, and the concentrations of both dissociated and undissociated forms of the appropriate weak acid in the medium were monitored at 1-h intervals during 24 h of incubation. The inhibitory effect of each compound on the growth of microorganisms was calculated based on measurement of optical density at 600 nm turbidity. The K parameter, defined as the ratio of the concentration of undissociated weak acid to the number of microorganisms in the medium, was determined. The K value is related to the degree of growth inhibition and provides new insight into the mode of action of weak organic acids against the studied yeasts. The buffering capacity of the chemicals studied was also found to be an inhibition parameter associated with microbial growth. Greater buffer capacity of a given compound reduced changes in the pH value of the medium, resulting in changes to antimicrobial effectiveness.

In-medium effects on phase space distributions of antikaons measured in proton-nucleus collisions.

Differential production cross sections of K+/- mesons have been measured in p + C and p + Au collisions at 1.6, 2.5, and 3.5 GeV proton beam energy. At beam energies close to the production threshold, the K- multiplicity is strongly enhanced with respect to proton-proton collisions. According to microscopic transport calculations, this enhancement is caused by two effects: the strangeness exchange reaction NY --> K- NN and an attractive in-medium K- N potential at saturation density.

Vibrational and microbiological study on alkaline metal picolinates and o-iodobenzoates.

FT-IR and Raman experimental data were assigned to appropriate bond vibrations and used to compare the different electronic charge distributions in the aromatic rings and carboxylic anions of various lithium, sodium, potassium, rubidium and caesium o-iodobenzoates and picolinates. Then principal component analysis (PCA) was applied in order to attempt to distinguish the biological activities of these compounds according to selected band wavenumbers. The growth of the bacteria Escherichia coli and Bacillus subtilis and the yeasts Saccharomyces cerevisiae and Hansenula anomala under optimal growth conditions were measured after 24 hours of incubation by the classical plate method. The influence of the picolinates and o-iodobenzoates on the growth of these microorganisms, again after 24 hours of incubation, was also measured and compared to the effect of sodium benzoate, which was used as a reference material. In general, the o-iodobenzoates exhibited more activity against the microorganisms than the picolinates. A statistically significant linear correlation between the spectral data and the degree of influence of a given compound on microorganism growth was established. The correlation coefficients for the o-iodobenzoates were 0.696, -0.628, 0.693 and 0.755 for E. coli, B. subtilis, H. anomala and S. cerevisiae, respectively, and for the picolinates they were 0.818, 0.826, 0.821 and 0.877 for E. coli, B. subtilis, H. anomala and S. cerevisiae, respectively. Therefore, IR spectroscopy is shown to be a rapid and reliable analytical tool for preliminary estimation of the antimicrobial properties of newly synthesized compounds, that can be applied before microbial performance tests.

Observation of different azimuthal emission patterns of K+ and of K- mesons in heavy-ion collisions at 1-2 A GeV.

Azimuthal distributions of pi+, K+, and K- mesons have been measured in Au+Au reactions at 1.5A GeV and Ni+Ni reactions at 1.93 A GeV. In semicentral collisions at midrapidity, pi+ and K+ mesons are emitted preferentially perpendicular to the reaction plane in both collision systems. In contrast for K- mesons in Ni+Ni reactions, an in-plane elliptic flow was observed for the first time at these incident energies.

The relationship between chemical structure and antimicrobial activity of selected nicotinates, p-iodobenzoates, picolinates and isonicotinates.

Alkaline metal, calcium and magnesium p-iodobenzoates and alkaline metal nicotinates, as well as sodium and potassium picolinic and isonicotinates were investigated by means of their antimicrobial and chemical properties. The quality estimation of the influence of metal cation coordinated to the carboxylic anion of the series of studied compounds on their antimicrobial activity as well as on the vibrational structure of whole complex in water solution was done. The changes in antimicrobial properties and in charge distribution of the complex along the position of nitrogen atom in the aromatic ring in sodium and potassium complexes were investigated. The analysis of influence of iodine substituent in para position on the change of electronic charge distribution of carboxylate anion and aromatic ring was done. The relationship between electronic properties estimated by vibrational spectroscopy and antimicrobial activity of studied complexes was investigated.

Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow.

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.

First evidence for different freeze-out conditions for kaons and antikaons observed in heavy-ion collisions.

Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.

The influence of selected metals on the electronic system of biologically important ligands.

The influence of (i) halogens, (ii) different alkaline cations, Li(I), Na(I), K(I), Rb(I) and Cs(I), and (iii) lanthanide cations, Pr(III), Nd(III), Dy(III) and Er(III) on the electronic structure of the aromatic ring as well as of the carboxylic anion of the substituted benzoic acids was investigated. Systematic change (decrease or increase) in the wavenumbers of selected bands along the F-->Cl-->Br-->I series was observed. This change correlates in linear fashion with a decrease in the ionic potential of the halogens. A shift of the selected bands along with the alkaline and the lanthanide metal series was also observed and correlated with the ionic potential of the metal. It was noticed that the increase in the ionic potential of halogen atoms causes a remarkable increase in the difference (Deltanu) between the wavenumbers of nuasym(COO-) and nusym(COO-). Among the halogens the ionic potential is the lowest for iodine and this substituent brings about maximal proximity of the asymmetric and symmetric bands of the carboxylic anion. The change of cation in the molecule causes a characteristic change in the difference (Deltanu) between the wavenumbers of nuasym(COO-) and nusym(COO-) as well. Along with the lanthanide series under study (Pr-->Nd-->Dy-->Er) this difference decreases, while between alkaline cations lithium broadens these bands to the highest degree. The influence of the alkaline and the lanthanide cations on the vibrational structure of the whole molecule was analysed and compared.

Coulomb dissociation of 8B and the low-energy cross section of the 7Be(p,gamma)8B solar fusion reaction.

An exclusive measurement of the Coulomb breakup of 8B into 7Be+p at 254A MeV allowed the study of the angular correlations of the breakup particles. These correlations demonstrate clearly that E1 multipolarity dominates and that E2 multipolarity can be neglected. By using a simple single-particle model for 8B and treating the breakup in first-order perturbation theory, we extract a zero-energy S factor of S17(0)=18.6+/-1.2+/-1.0 eV b, where the first error is experimental and the second one reflects the theoretical uncertainty in the extrapolation.

m-Iodobenzoic acid complexes with selected metals: molecular structure and antimicrobial activity.

Complexes of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, manganese, and zinc with m-iodobenzoic acid were studied. The FT-IR and FT-Raman spectra of the mentioned compounds in the solid state and water solutions were recorded and analyzed. Principal component analysis (PCA) was performed on the wavenumbers of selected bands (eight bands) occurring in the vibrational spectra. The numbers obtained as a result of this procedure characterize the electronic properties of the molecule of each complex. The antimicrobial activity of the studied compounds against selected bacteria (Escherichia coli and Bacillus subtilis) and yeast (Saccharomyces cerevisiae and Hansenula anomala) was estimated. The relationship between the chemical properties (as characterized by PCA of the IR spectra) and antimicrobial properties of the compounds was examined, and a good correlation between the two factors was found.

Emission pattern of high-energy pions: A new probe for the early phase of heavy-Ion collisions

The emission pattern of charged pions has been measured in Au+Au collisions at 1 GeV/nucleon incident energy. In peripheral collisions and at target rapidities, high-energy pions are emitted preferentially towards the target spectator matter. In contrast, low-energy pions are emitted predominantly in the opposite direction. The corresponding azimuthal anisotropy is explained by the interaction of pions with projectile and target spectator matter. This interaction with the spectator matter causes an effective shadowing which varies with time during the reaction. Our observations show that high-energy pions stem from the early stage of the collision whereas low-energy pions freeze out later.

The influence of selected metals and halogens on the electronic system of benzoic acid.

The influence of halogens and metals on the electronic system of the aromatic ring in lithium, sodium and potassium complexes with p-halogenobenzoic acids has been investigated by means of (13)C and (1)H NMR, IR and Raman spectroscopy and semi-empirical calculations. It has been shown that ionic potentials and electronegativities of halogens and metals are the main factors responsible for perturbations of the electronic charge distribution in the ring.