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Abstract: We constructed the pp-wave limit of superconformal mechanics with the off-shell multiplet. We present the superfield and the component actions which exhibit the interesting property that the interaction parts are completely fixed by the symmetry. We also explicitly demonstrate that the passing to the pp-wave limit can be achieved by keeping at most quadratic nonlinearities in the action of (super)conformal mechanics. [Copyright &y& Elsevier]

Abstract: We construct supersymmetric mechanics using the nonlinear chiral supermultiplet. The two bosonic degrees of freedom of this supermultiplet parameterize the sphere and go into the bosonic components of the standard chiral multiplet when the radius of the sphere goes to infinity. We construct the most general action and demonstrate that the nonlinearity of the supermultiplet results in the deformation of the connection, which couples the fermionic degrees of freedom with the background, and of the bosonic potential. Also a non-zero magnetic field could appear in the system. [Copyright &y& Elsevier]

We show that families of nonlinear gravity theories formulated in a metric-affine approach and coupled to a nonlinear theory of electrodynamics can be mapped into general relativity (GR) coupled to another nonlinear theory of electrodynamics. This allows to generate solutions of the former from those of the latter using purely algebraic transformations. This correspondence is explicitly illustrated with the Eddington-inspired Born-Infeld theory of gravity, for which we consider a family of nonlinear electrodynamics and show that, under the map, preserve their algebraic structure. For the particular case of Maxwell electrodynamics coupled to Born-Infeld gravity we find, via this correspondence, a Born-Infeld-type nonlinear electrodynamics on the GR side. Solving the spherically symmetric electrovacuum case for the latter, we show how the map provides directly the right solutions for the former. This procedure opens a new door to explore astrophysical and cosmological scenarios in nonlinear gravity theories by exploiting the full power of the analytical and numerical methods developed within the framework of GR.

Due to the increased emphasis on cost-containment, drugs must be proven not only to be safe and effective, but also to reduce costs, prior to be used in clinical practice. In the context of this saving policy, 12 clinically stable patients on hemodialysis who were administered darbepoetin-alpha (Aranesp (DARB) for at least 16 months in single weekly doses, were converted to EPO-alpha, administered 2-3 times per week. The initial dose of EPO-alpha was calculated on the basis of a dose-conversion ratio (DCR) of 200 IU EPO-alpha = 1 mcg DARB. The mean Hb value in the six months preceding the conversion was between 11 and 12 g/dL, with a monthly dose of DARB unchanged/ reduced during the last three months. During the last month of treatment with DARB, the mean Hb value of the cohort was 11.4+/-0.5 g/dL and the mean weekly dose per patient was 24 +/- 12 mcg. After two months of EPO-alpha use, the mean Hb value dropped to 10.8+/-0.7 g/dL, with a mean monthly dose per patient of 5.667+/-2.229 IU, corresponding to a DCR of 234. In order to bring the Hb values back to above 11 g/dL, doses of EPO-alpha were progressively increased up to a maximum of 10.000+/-5.461 IU per patient, corresponding to a DCR of 414. The attempt to convert 12 hemodialysis patients treated with darbepoetin-alpha to an ESA with an apparent lower cost resulted in a worsening of the anemia of the patients after the conversion. Instead of leading to savings, the conversion actually increased expenditures.

Background: The self-locating catheter invented by Nicola Di Paolo has been used increasingly in Italy and elsewhere since 1994, with about a thousand patients currently implanted every year. Twelve grams of tungsten inserted into the tip of the conventional Tenckhoff catheter during extrusion does not significantly change its form, but suffices to keep the tip firmly in the Douglas cavity., Objective: The aim of the present study was to confirm our preliminary results in a large population of peritoneal dialysis patients., Setting: 16 Italian nephrology departments., Results: In addition to confirming the validity of the new catheter, the present results show that patients with the new catheter have fewer episodes of peritonitis, tunnel infection, cuff extrusion, catheter malfunction, obstruction, and leakage., Conclusion: The present multicenter control study confirms preliminary results and demonstrates that complications of peritoneal dialysis, such as cuff extrusion, infection, peritonitis, early leakage, and obstruction, are statistically less frequent in patients with self-locating catheters than in patients with classic Tenckhoff catheters.

The side effects of glucose degradation products (GDPs) in conventional peritoneal dialysis (PD) fluids are well described. Using the three-compartment bag concept--that is, in situ preparation of concentrated glucose solution into a standard ionic solution--a GDP-free solution can be processed. To investigate the possible impact of this product on biological and clinical parameters, we carried out a prospective cross-over study with 31 patients, comparing the short-term effects of conventional PD and GDP-free PD solutions. Classical peritoneal parameters and ultrafiltration rate did not change during the study. After three months and after six months with the three-compartment bag, cancer antigen 125 (CA125) concentration in overnight fluid increased significantly (p < 0.001) from 24.4 IU/mL to 44.4 IU/mL and 41.1 IU/mL respectively. CA125 decreased significantly (p < 0.01) to 21.7 IU/mL after three months with the conventional solution. No change in hyaluronan concentration was observed. A slight increase of procollagen III N-terminal peptide in overnight effluent with the GDP-free solution was followed by a significant reduction after three months with standard solution. In summary, our data show that the GDP-free PD fluid improves mesothelial cell mass and turnover even after a short-term period of three months. A better quality of PD solution is obtained by using the three-compartment bag.

Peritonitis is a crucial complication of peritoneal dialysis. Over the last few years, new device systems have been developed to reduce episodes of peritonitis caused by exogenous contamination. Remarkable improvement has been obtained by modifying the original connection between the catheter and the bag with the introduction of the Y-set. The aims of this study were to test the reliability and simple use of a double-bag system without disinfectant in-line (Gemini, Gambro) and to evaluate the incidence of peritonitis in a 2-year period of follow-up. In a group of 167 patients, enrolled in 14 dialysis units in Italy, with a follow-up of 2433 patient-months, we observed 82 episodes of peritonitis in 52 patients, with a cumulative incidence of 1 episode every 29.7 patient-months. At 12 months the percentage of patients peritonitis-free was 69.7%, and at 24 months it was 62.8%. The training to complete the bag exchange, assessed by patient and nursing staff, was defined as "easy" in 61% of the cases and "difficult" in only 12% of the cases. The percentage of patients requiring a partner was 23%. For patients this device system presents easy handling in terms of the bag exchange, and it may prevent peritonitis.