Probing Isospin Dynamics in Halo Nuclei

Nuclear many-body theory is used to study nuclear matter and finite nuclei at extreme isospin. In-medium interactions in asymmetric nuclear matter are obtained from (Dirac-) Brueckner theory. Neutron skin formation in Ni and Sn isotopes is investigated by relativistic mean-field calculations in DDRH theory with density dependent meson-nucleon vertices. Applications to light nuclei are discussed with special emphasis on pairing and core polarization in weakly bound nuclei. Approaches accounting for continuum coupling in dripline pairing and core polarization are presented. Calculations for the halo nuclei $^8$B, $^{11}$Be and $^{19}$C show that shell structures are dissolving when the driplines are approached. Relativistic breakup data are well described by eikonal calculations.Comment: 10 pages, 8 figure

Design of Polyamine-Grafted Starches for Nucleotide Analogue Delivery: In Vitro Evaluation of the Anticancer Activity

Nucleotide analogues are a therapeutic class that is very promising and currently used in clinics, notably against viral infectious diseases and cancer. However, their therapeutic potential is often restricted by a poor stability in vivo, the induction of severe side effects, and limited passive intracellular diffusion due to their hydrophilicity. Polysaccharide-based polymers (e.g., starch) have considerable advantages, including a lack of toxicity and the absence of antigenicity. The aim of this study was to develop new cationic starches able to form complexes with nucleotide analogues, thus protecting them and increasing their cell uptake. At the same time, the material should demonstrate good biocompatibility and low cytotoxicity. Different polyamines, (TREN, TEPA, and spermine) were grafted to starch to evaluate the impact of side-chain properties. The resulting cationic starch derivatives were characterized (e.g., degree of modification) and compared in their ability to form polyplexes with ATP as a model nucleotide. Among the tested candidates, the formulation of starch–TEPA and ATP with an N/P ratio of 2 led to nanoparticles with a size of 429 nm, a PdI of 0.054, and a ζ potential of −9 mV. MTT and LDH assays on A549 cell line showed low toxicity for this polymer. Confocal microscopy study proved that the cell internalization was an incubation-time- and energy-dependent process. Most important, starch–TEPA complexed with ddGTP showed significant biological activity on A549 cancer cells compared to that of plain ddGTP at the same concentration

Design of polyamines-grafted starches for nucleotide analogues delivery: in vitro evaluation of the anticancer activity

Nucleotide analogues are a therapeutic class really promising and currently used in clinic notably against viral infectious diseases and cancer. However, their therapeutic potential is often restricted by a poor stability in vivo, the induction of severe side effects and a limited passive intracellular diffusion due to their hydrophilicity. Polysaccharide-based polymers (e. g. starch) have considerable advantages including a lack of toxicity and absence of antigenicity. The aim of this study was to develop new cationic starches able to form complexes with nucleotide analogues: to protect them and increase their cell uptake. The material should demonstrate good biocompatibility and low cytotoxicity. Different oligoamines, (TREN, TEPA and spermine) were covalently grafted to starch: the resulting cationic starch derivatives were characterized (e.g. degree of modification) and compared in their properties to form polyplexes with ATP as a model nucleotide. Among the tested candidates, the formulation of starch-TEPA and ATP with a N/P ratio = 2 led to nanoparticles with a size of 429 nm, a PdI of 0.054 and a zeta potential of -9 mV. MTT and LDH assays on A549 cell line showed a low toxicity of this cationic starch. Confocal microscopy studies proved that the cell internalization was an incubation time and energy dependent process. Most important, starch-TEPA complexes with ddGTP (0.3 mg/mL) showed a significant biological activity on A549 cancer cells (> 90 %) compared to plain ddGTP (~ 21 %) at the same concentration, revealing a real promising system to deliver intracellularly nucleotide analogues

Photoproduction of phi mesons from nuclei

We investigate the consequences of possible medium modifications of the phi meson at finite nuclear matter density on the K+K- mass distribution in photonuclear reactions. The inclusive cross sections for K+K- pair production are calculated within a semi--classical BUU transport model, which combines the initial state interaction of the incoming photon with the final state interactions of the produced particles. The effects of final state interactions on the invariant mass distribution of the observed K+K- pairs are discussed in detail. In addition we calculate the Coulomb correction and possible effects of hadronic kaon potentials on the K+K- mass spectrum. Due to the large cross sections for reactions of the final state particles with the surrounding nuclear medium and the influence of the Coulomb potential we find no measurable sensitivity of the observables to the phi properties at finite baryon density.Comment: revtex4, 24 page

Pulmonary surfactant is indispensable in order to simulate the <em>in vivo</em> situation.

The article of Gasser et al. [Part Fibre Toxicol. 24; 9:17, 2012] describes the interaction of carbon nanotubes with cells within a complex cell culture model. Besides various toxicity parameters, the influence of coating with pulmonary surfactant was investigated. Pulmonary surfactant covers the entire alveolar region with the main function of decreasing the surface tension in the alveoli to prevent alveolar collapse. Although each inhaled nanoparticle, reaching the alveoli, will come into contact with pulmonary surfactant which will probably lead to a surfactant coating, pulmonary surfactant components are not commonly integrated in in vitro systems. Gasser and co-workers have shown that this surfactant coating is able to influence the further interaction with cellular systems. Hence, each scientist, working with in vitro systems and nanoparticles, should think of integrating pulmonary surfactant structures in order to harmonize the in vitro systems with the in vivo situation. In the present commentary we discuss the most important points of the manuscript of Gasser et al. and discuss where the usage of pulmonary surfactant can be further optimized

Nortriptyline hydrochloride skin absorption: development of a transdermal patch

[EN] The influence of propylen glycol (PG), ethanol, and oleic acid (OA) on nortriptyline hydrochloride (NTH) penetration through human epidermis was studied in vitro at two different pH values (5.5 and 7.4). The influence of lactic acid and polysorbate 80 was studied for a pH of 5.5. Permeation studies through Heat Separated Epidermis, as well as the enhancing effect of the different vehicles, showed a pH dependency. A pH value of 5.5 in the donor solution decreases significantly the permeability coefficient (Kp) with respect to a pH value of 7.4 (0.011+/-0.004 x 10(-6) versus 0.36+/-0.04 x 10(-6)cm/s). The vehicles showed an increasing enhancement effect in the order: polysorbate 80>ethanol/PG/OA>PG>ethanol>ethanol/lactic acid>lactic acid at pH 5.5 while they reduced the permeation of NTH at pH 7.4. Considering the results obtained at pH 5.5, the maximum enhancement ratios were found for polysorbate 80 and the combination ethanol/PG/OA (10.72 and 3.90). Both vehicles were selected for designing a NTH transdermal delivery system (NTH-TDS) using (hydroxypropyl)methyl-cellulose as polymer. The NTH-TDS based on the combination of ethanol/PG/OA showed an enhancement ratio with respect to control of 2.09 and the addition of polysorbate 80 to the matrix, of 5.82.The Galenos Network-Marie Curie-Fellowship agreement in the framework of the EU Project "Towards a European Ph.D. in Advanced Drug Delivery" MESTCT-2004-504992. Funds were received from the Generalitat Valenciana (GV06-163). The authors thank Dr. Javier Pascual (Hospital 9 Octubre, Valencia) and Dr. Karl-Heinz Kostka (Caritas Krankenhaus, Lebach) for providing the human skin samples.Melero, A.; Garrigues, T.; Almudéver-Folch, P.; Martín Villodre, A.; Lehr, C.; Schäfer, U. (2008). Nortriptyline hydrochloride skin absorption: development of a transdermal patch. European Journal of Pharmaceutics and Biopharmaceutics. 69(2):588-596. https://doi.org/10.1016/j.ejpb.2007.11.01258859669