Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive

There is sparse direct experimental evidence that atomic nuclei can exhibit stable "pear" shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole (E3) matrix elements have been determined for transitions in ^{222,228}Ra nuclei using the method of sub-barrier, multistep Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of E3 matrix elements for different nuclear transitions is explained by describing ^{222}Ra as pear shaped with stable octupole deformation, while ^{228}Ra behaves like an octupole vibrator.

Publisher Correction: The observation of vibrating pear-shapes in radon nuclei.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The observation of vibrating pear-shapes in radon nuclei.

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

Effect of pedaling rates and myosin heavy chain composition in the vastus lateralis muscle on the power generating capability during incremental cycling in humans.

In this study, we have determined power output reached at maximal oxygen uptake during incremental cycling exercise (P(I, max)) performed at low and at high pedaling rates in nineteen untrained men with various myosin heavy chain composition (MyHC) in the vastus lateralis muscle. On separate days, subjects performed two incremental exercise tests until exhaustion at 60 rev min(-1) and at 120 rev min(-1). In the studied group of subjects P(I, max) reached during cycling at 60 rev min(-1) was significantly higher (p=0.0001) than that at 120 rev min(-1) (287+/-29 vs. 215+/-42 W, respectively for 60 and 120 rev min(-1)). For further comparisons, two groups of subjects (n=6, each) were selected according to MyHC composition in the vastus lateralis muscle: group H with higher MyHC II content (56.8+/-2.79 %) and group L with lower MyHC II content in this muscle (28.6+/-5.8 %). P(I, max) reached during cycling performed at 60 rev min(-1) in group H was significantly lower than in group L (p=0.03). However, during cycling at 120 rev min(-1), there was no significant difference in P(I, max) reached by both groups of subjects (p=0.38). Moreover, oxygen uptake (VO(2)), blood hydrogen ion [H(+)], plasma lactate [La(-)] and ammonia [NH(3)] concentrations determined at the four highest power outputs completed during the incremental cycling performed at 60 as well as 120 rev min(-1), in the group H were significantly higher than in group L. We have concluded that during an incremental exercise performed at low pedaling rates the subjects with lower content of MyHC II in the vastus lateralis muscle possess greater power generating capabilities than the subjects with higher content of MyHC II. Surprisingly, at high pedaling rate, power generating capabilities in the subjects with higher MyHC II content in the vastus lateralis muscle did not differ from those found in the subjects with lower content of MyHC II in this muscle, despite higher blood [H(+)], [La(-)] and [NH(3)] concentrations. This indicates that at high pedaling rates the subjects with higher percentage of MyHC II in the vastus lateralis muscle perform relatively better than the subjects with lower percentage of MyHC II in this muscle.

Influence of near-infrared radiation on the pKa values of L-phenylalanine.

The effect of pH on L-phenylalanine (L-phe) before and after exposure to near-infrared (NIR) radiation (15 min, 700-2000 nm) was investigated by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Characteristic bands of L-phe were described and the pK(a) values were retrieved from IR spectra by using an intensity ratio method according to our recent paper (Olsztynska et al., Appl. Spectrosc. 55, 901 (2001)). It has been found that the irradiation process modifies pK(a) values of L-phe. The spectroscopic study clearly shows the shift of acid-base equilibrium after exposure to NIR radiation. The phenomenon is due to modification of the water structure. Intra- and intermolecular hydrogen bonds weaken, which could induce conformational changes of the phe molecule. Subsequently, hydrophobic interactions strongly increase. These processes favor aggregation of phe molecules, which leads to deprotonation of the -NH(3)(+) to -NH(2) group and protonation of the -COO(-) to -COOH group, changing the pK(a) values.

Water evaporation analysis of L-phenylalanine from initial aqueous solutions to powder state by vibrational spectroscopy.

The water evaporation from L-phenylalanine (L-phe) aqueous solutions at different initial pH (0-13) was studied by vibrational spectroscopy. Next, the attenuated total reflection-Fourier transform infrared (ATR-FT-IR) spectra of aqueous solutions were compared to those recorded after drying for 72 h at 21 degrees C at appropriate initial pH values. Micro-Raman results collected after the water evaporation process are also presented and interpreted. Between pH = 2.5 and 8.76 a white non-transparent gel was observed, possibly due to the presence of the NaCl salt. The significant differences of the band intensities of L-phe functional groups noticed at pH near pK(a) values indicate the structural changes of L-phe molecules due to dimer formation (hydrogen bonds between the -COOH and -CO(2)(-) groups, and the -NH(3)(+) and -NH(2) groups). The presence of the hydrophobic interactions leads to the aggregation of L-phe molecules, most probably via phe-phe stacking as well as complexes of phe with Na(+) ions, HCl, or H(2)O molecules.

The effects of glutaraldehyde and osmium tetroxide on the erythrocyte membrane. A spin label study.

A nitroxide spin label probe technique was applied to study the interaction between glutaraldehyde or osmium tetroxide (OsO4) amd the membranes of horse erythrocytes, ghosts and liposomes prepared from erythrocyte lipids. Two major conclusions have been established: (1) Reaction of the fixation reagents with the membrane is selective. OsO4 reacts predominantly with lipids and glutaraldehyde with membrane proteins. (2) The lipid-protein interactions change after pretreatment by OsO4 or glutaraldehyde.

The interaction of fructose-1,6-biphosphate aldolase with liposome membranes: a spin probe technique study.

Thermotropic properties of liposome membranes prepared of bulk bovine erythrocyte membrane lipids, native, or aldolase-modified, were investigated by the ESR method. Breaks were observed in the log 2T parallel vs 1/T plots for two spin labels: tempopalmitate and 5-doxyl-palmitate methyl ester. These phenomena have been interpreted as reflecting structural changes near the lipid bilayer polar heads region. Upon modification with aldolase, the temperature at which the breaks occurred was decreased for both spin probes.

Phase transitions in spherical bilayer membranes prepared of bulk erythrocyte membrane lipids.

The phase transitions of spherical lipid bilayers built of bovine red cell lipids have been studied. The electrical and ESR measurements revealed some conformational changes in lipid bilayers taking place at 36-38 degrees C.

Antioxidant activity of flavones from Scutellaria baicalensis in lecithin liposomes.

The antioxidant effect of a trihydroxyflavone extract from Scutellaria baicalensis on oxidation induced by ultraviolet light, was studied with phosphatidylcholine liposome membrane. Also, as standards, the antioxidative activity of baicalin, wogonin, baicalein and butylated hydroxytoluene (BHT) was investigated. Comparison of the protective effects of the compounds studied against photoinduced lipid peroxidation in lecithin liposome membranes showed that: (1) the inhibitory effect of those compounds (at 1.2 mol% antioxidant content in liposomes) on TBA reactive materials from lipid peroxidation decreased in the order of baicalin > BHT approximately equal to Scutellaria baicalensis. These were found much greater than wogonin and baicalein; (2) the depressed effect of those compounds (at 1.1 mol% compounds content in liposomes) on the production of conjugated dienes (proportional to oxidation index) could be classified as follows: Scutellaria baicalensis approximately equal to baicalin > BHT, these three were found more active much greater than baicalein and wogonin. Results obtained by ESR measurement confirm that Scutellaria baicalensis extract and the BHT compound significantly depressed the effect of liposome oxidation. It was found that the new trihydroxyflavones of Scutellaria baicalensis, ensured a very satisfactory concentration-dependent protection of the liposome membrane against UV-induced oxidation. These findings suggest that some of the beneficial effects of the extract of the Scutellaria baicalensis can be mediated in certain diseases (for example in skin diseases) by their ability to scavenge free radicals and by their protective effect on lipid peroxidation caused by sunlight irradiation.

Anthocyanin extracts with antioxidant and radical scavenging effect.

The antioxidative activity of three anthocyanin pigments, extracted from the fruits of chokeberry, honeysuckle and sloe, were studied. Lipid oxidation in the liposome membrane, induced by UV radiation, was evaluated with a thiobarbituric acid-reactive substances assay. The antioxidant efficiency of the studied compounds follows this sequence: chokeberry > sloe > honeysuckle. The extract concentrations at which a 50% reduction of phosphatidylcholine oxidation was observed, were respectively: 48, 54 and 60 mg/l. The end products of lipid membrane oxidation were evaluated using HPLC. It was found that the antioxidative potency of anthocyanin extracts is concentration-dependent. As shown by EPR technique the efficiency of the extracts to eliminate free radicals from the solution follows the order of the antioxidant activity.

University of Lodz an electron spectrometer--a new conversion-electron spectrometer for "in-beam" measurements.

The designed and constructed at the University of Lodz an electron spectrometer is devoted to "in-beam" measurements. The apparatus is characterized by high efficiency up to 9%, good energy resolution (FWHM = 5 keV at 482 keV) and, what is very important good suppression of delta electrons, positrons, and photons emitted by the targets. This achievement was obtained using a combination of magnetic field in two different layouts: perpendicular and parallel to the axis of the spectrometer being orthogonal to the beamline. The conversion-electron spectrometer coupled to the EAGLE array was successfully tested in an "in-beam" measurement.

FT-Raman spectroscopic study of human skin subjected to uniaxial stress.

Fourier Transform Raman Spectroscopy was used to investigate the molecular changes of structural proteins in human skin subjected to strain. In the Raman spectrum of unstrained skin, bands assigned mainly to collagen and elastin were observed at 1658 cm(-1) (amide I), 1271 and 1255 cm(-1) (amide III), and 935 and 817 cm(-1) (C-C stretching modes of the protein backbone). Moreover, bands characteristic for amino acids were observed at 1336 cm(-1) (desmosine), 1004 cm(-1) (phenylalanine), 919 and 856 cm(-1) (proline), and 877 cm(-1) (hydroxyproline). Positions and intensities of the listed Raman bands were analysed as a function of applied strain. A clear correlation between Raman wavenumbers and the level of mechanical stress was established. Wavenumbers of the analysed bands changed gradually with increasing strain. Distinct responses, depending on the sample cutting direction, i.e. longitudinal or perpendicular to the Langer's lines, were noticed. It was concluded that elastin and non-helical domains of collagen are initially involved in the load transfer and triple helices of collagen are gradually joining this process. It was proved that Raman spectroscopy give insight into skin deformation micromechanics.

Near-infrared radiation protects the red cell membrane against oxidation.

The antioxidant effects of near-infrared radiation (NIR) in vitro (700-200 nm) on human erythrocytes was studied as a continuation of our earlier studies. The changes of: ratio of hemolysis, electrokinetic potential, lipids peroxidation, autohemolysis, and fluidity of red cell lipid bilayer were studied for intact, irradiated, ozonated and irradiated, and ozonated erythrocytes. We revealed that, under in vitro condition, the oxidation of red cells by ozone decreased lipids' bilayer fluidity in the vicinity of the 5th carbon and increased fluidity on the 16th carbon level of hydrocarbon chains, induced autohemolysis, oxidized lipids, and changed the electrokinetic potential. However, when erythrocytes were exposed to near-infrared radiation (NIR) and later ozonated, measured parameters were the same as that for control cells kept in darkness or markedly less modified than that ozonated. In conclusion, these observations suggest protective action of NIR radiation on the erythrocyte membrane. The results support the idea that during exposition to NIR, dehydration process induces the photochemical dissociation oxyhemoglobin to deoxyhemoglobin. Deoxygenation leads to phosphorylation of cytoplasmic domain of band 3 at tyrosine 8 that strengthens its association with the spectrin network. An increased association between band 3 and the underlying skeleton elevated the cell membrane mechanical resistance that could protect them before autohemolysis. Also, weakening hydrogen bonds on the surface of erythrocyte membranes moderate the surface charge, lowering the accessibility of charged free radicals from ozone solution into cells.

Near-infrared induced membrane surface electrostatic potential, fluorescent measurements.

The change of the electrostatic surface potential induced by near-infrared radiation was monitored by the fluorescence probe technique. Fluorescence intensity of 1-anilinonaphtalene-8-sulfate (ANS) was studied in the pH range 4.8-9.5 before and after exposition to NIR (700-2000 nm). The intensity of fluorescence changed (decreased after exposition on radiation) only at pH 7.4. The effect is due to decreasing concentration of ANS in liposome membrane after irradiation. The modified distribution of ANS in liposome membrane upon irradiation is attributed to the dehydration of membrane surface. Dehydratation diminishes the electrostatic surface potential about 36+/-15 mV.

Free amino acids in basal and vagally stimulated gastric secretion.

The concentrations of the individual free amino acids were determined in one hour fraction of basal secretion and peak hydrogen ion secretion following stimulation with 2-deoxy-D-glucose (2-DG) (group I) or insulin (group II). Group I consisted of 9 patients with duodenal ulcer having hypersecretion of gastric acid as determined by histamine test; 7 patients with duodenal ulcer who underwent truncal vagotomy and had insulin test performed two weeks after the operation formed group II. The total concentration of free amino acids was similar in basal and in stimulated gastric juice in both groups. Also the concentrations of the individual amino acids did not change significantly after stimulation. There was, however, a significant increase following stimulation in the output of amino acids both in group I and in group II. This increase was parallel to that in the volume of gastric juice, which suggests that a definite amount of free amino acids is always present in the gastric juice, and that the secretion of these acids is not under vagal control.