Role of final state interaction and of three-body force on the longitudinal response function of 4He

We present an ab-initio calculation of the longitudinal electron scattering response function off 4He with two- and three-nucleon forces and compare to experimental data. The full four-body continuum dynamics is considered via the Lorentz integral transform method. The importance of the final state interaction is shown at various energies and momentum transfers q. The three-nucleon force reduces the quasi-elastic peak by 10% for q between 300 and 500 MeV/c. Its effect increases significantly at lower q, up to about 40% at q=100 MeV/c. At very low q, however, data are missing.Comment: 4 pages, 3 figures, corrected typos, shorter versio

Photonuclear sum rules and the tetrahedral configuration of 4^4He

Three well known photonuclear sum rules (SR), i.e. the Thomas-Reiche-Kuhn, the bremsstrahlungs and the polarizability SR are calculated for 4He with the realistic nucleon-nucleon potential Argonne V18 and the three-nucleon force Urbana IX. The relation between these sum rules and the corresponding energy weighted integrals of the cross section is discussed. Two additional equivalences for the bremsstrahlungs SR are given, which connect it to the proton-neutron and neutron-neutron distances. Using them, together with our result for the bremsstrahlungs SR, we find a deviation from the tetrahedral symmetry of the spatial configuration of 4He. The possibility to access this deviation experimentally is discussed.Comment: 13 pages, 1 tabl

X-ray Tail in NGC 7619

We present new observational results of NGC 7619, an elliptical galaxy with a prominent X-ray tail and a dominant member of the Pegasus group. With Chandra and XMM-Newton observations, we confirm the presence of a long X-ray tail in the SW direction; moreover, we identify for the first time a sharp discontinuity of the X-ray surface brightness in the opposite (NE) side of the galaxy. The density, temperature and pressure jump at the NE discontinuity suggest a Mach number ~1, corresponding to a galaxy velocity of ~500 km s-1, relative to the surrounding hot gas. Spectral analysis of these data shows that the Iron abundance of the hot gaseous medium is much higher (1-2 solar) near the center of NGC 7619 and in the tail extending from the core than in the surrounding regions (< 1/2 solar), indicating that the gas in the tail is originated from the galaxy. The possible origin of the head-tail structure is either on-going ram-pressure stripping or sloshing. The morphology of the structure is more in line with a ram pressure stripping phenomenon, while the position of NGC 7619 at the center of the Pegasus I group, and its dominance, would prefer sloshing.Comment: ApJ accepted to appear in the 2008 December 1 issue; Added discussion on sloshin

Potential Anticancer Activity against Human Epithelial Cancer Cells of Peumus Boldus Leaf Extract

The potential in vitro antineoplastic effect has been studied of a methanolic extract of leaves of Peumus boldus Molina (Monimiaceae) on two human cancer epithelial cell lines, DU-145 cells (androgen-insensitive prostate cancer cells) and KB cells (oral squamous carcinoma cells). Our findings show that this extract exhibited comparable effects on the cancer cells examined as judged by IC50 values (5.07±0.4 μg/mL and 5.28±0.5 μg/mL in DU-145 and KB cells, respectively). In addition, with respect to genomic DNA damage, determined by Comet assay, the results obtained show a high fragmentation of DNA, not correlated to lactic dehydrogenase (LDH) release, a marker of membrane breakdown, in both cell lines treated with the extract at 5–20 μg/mL concentrations. Taken together, our experimental evidence may justify further investigation of the chemopreventive and chemotherapeutic potential of this natural drug

Mechanisms of HIV-1 Nucleocapsid Protein Inhibition by Lysyl-Peptidyl-Anthraquinone Conjugates

The Nucleocapsid protein NCp7 (NC) is a nucleic acid chaperone responsible for essential steps of the HIV-1 life cycle and an attractive candidate for drug development. NC destabilizes nucleic acid structures and promotes the formation of annealed substrates for HIV-1 reverse transcription elongation. Short helical nucleic acid segments bordered by bulges and loops, such as the Trans-Activation Response element (TAR) of HIV-1 and its complementary sequence (cTAR), are nucleation elements for helix destabilization by NC and also preferred recognition sites for threading intercalators. Inspired by these observations, we have recently demonstrated that 2,6-disubstituted peptidylanthraquinone-conjugates inhibit the chaperone activities of recombinant NC in vitro, and that inhibition correlates with the stabilization of TAR and cTAR stem-loop structures. We describe here enhanced NC inhibitory activity by novel conjugates that exhibit longer peptidyl chains ending with a conserved Nterminal lysine. Their efficient inhibition of TAR/cTAR annealing mediated by NC originates from the combination of at least three different mechanisms, namely, their stabilizing effects on nucleic acids dynamics by threading intercalation, their ability to target TAR RNA substrate leading to a direct competition with the protein for the same binding sites on TAR, and, finally, their effective binding to the NC protein. Our results suggest that these molecules may represent the stepping-stone for the future development of NC-inhibitors capable of targeting the protein itself and its recognition site in RNA

Biomarkers of aging

Aging is a complex process that negatively impacts the development of the different systems and its ability to function. Moreover, the Aging rate in humans is not the same, principally due to genetic heterogeneity and environmental factors. The aging rate is measured as the decline of functional capacity and stress resistance. Therefore, several attempts have been made to analyse the individual age, ( so-called biological age) compared to chronological age. The biomarkers of aging are age-related body function or composition, these markers aim to assess the biological age and predict the onset of age-related diseases and/or residual lifetime. Such biomarkers should help in one hand to characterise the biological age and on the other hand to identify individuals at high risk of developing age-associated diseases or disabilities. Unfortunately, most of the markers under discussion are related to age-related diseases rather than to age, so none of these markers discussed in literature is a true biomarker of aging. Hence, we discuss some disease-related biomarkers useful for a better understanding of aging and the development of new strategies to counteract it, essential for improving the quality of life of the elderly population

X-ray Luminosity Function and Total Luminosity of LMXB in Early Type Galaxies

We have derived bias-corrected X-ray luminosity functions (XLFs) of sources detected in a uniformly selected sample of 14 E and S0 galaxies observed with Chandra ACIS-S3. The entire sample yields 985 point-like X-ray sources, with typical detection of 30-140 sources per galaxy. After correcting for incompleteness, the individual XLFs are statistically consistent with a single power-law of a (differential) XLF slope b = 1.8 - 2.2 (with a typical error of 0.2-0.3). A break at or near LX,Eddington, as reported in the literature for some of these galaxies, is not required in any case. Although the combined XLF is marginally consistent with a single power-law (with b = 2.1 +- 0.1), a broken power-law gives an improved fit. The best-fit slope is b = 1.8 +- 0.2 in the low-luminosity range LX = a few x 1037 - 5 x 1038 ergs s-1. At higher luminosities, the slope is steeper, b = 2.8 +- 0.6. The break luminosity is 5 +- 1.6 x 1038 ergs s-1 (with an error at 90%), which may be consistent with the Eddington luminosity of neutron stars with the largest possible mass (3 Mo), of He-enriched neutron star binaries, or low-mass stellar mass black holes. If the change in XLF slope at high luminosities is real, our result would imply a different population of high luminosity sources, instead of a beaming effect. We confirm that the total X-ray luminosity of LMXBs is correlated with the optical and more tightly with the near-IR luminosities, but in both cases the scatter exceeds that expected from measurement errors. We find that the scatter in LX(LMXB)/LK is marginally correlated with the specific frequency of globular clusters.Comment: 31 pages, 3 tables, 8 figures, final version accepted by ApJ, slightly revised with more rebust error calculatio

Monitoring on chemical and biological pollutants in sea waters of central-northern Sardinia

Introduction. The aims of this study are to assess the quality of the coastal waters of central-northern Sardinia through data from a monitoring network and to outline maps and experimental models of environmental risk correlated to the presence of chemical and microbiological contaminants. The area studied is the coast between Capo Falcone and the mouth of the river Coghinas, in the northwestern part of the island. Methods. In a first phase, 7 sampling stations of sea water and 1sampling station of bivalve molluscs (Mytilus galloprovincialis Lam.) wereidentified. For each transept 3 different collection points at respectively 500, 1000, and 3000 meters from the coast for a total 21 sampling sites were identified. In a second phase, another 7 transepts wereidentified, 2 of which on the island of Asinara. Results. As regards the microbiological monitoring of the sea water, very low concentrations of Total coliforms, Faecal coliforms and Faecal Streptococci were found and no Salmonella were isolated. Chemical analysis of the waters showed a high constant presence of phenols. In the bivalves we found rather high concentrations of Faecal coliforms without any clear seasonal variation, while no Salmonella was isolated in any of the examined samples. Discussion. The results show that the considered area is not affected by serious pollution processes, thus allowing to express a completely satisfactory judgement on its state of health. However, anthropic pressure in the considered territory is testified by the presence in the water of high concentrations of phenols. Conclusions. The results point out to the necessity of targeted and rational preventive action by means of control and protection measures for environmental ecosytems

Microwave and ultrasound pre-treatments for ‘Rocha’ pear: impact on drying kinetics and selected quality attributes

info:eu-repo/semantics/acceptedVersio