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1. Maurer-Cartan Equations and Black Hole Superpotentials in N =8 Supergravity

Author

Ferrara, S., Marrani, A., and Orazi, E.

Subjects
High Energy Physics - Theory
Abstract

We retrieve the non-BPS extremal black hole superpotential of N=8, d=4 supergravity by using the Maurer-Cartan equations of the symmetric space E_7(7)/SU(8). This superpotential was recently obtained with different 3- and 4-dimensional techniques. The present derivation is independent on the reduction to d=3., Comment: 1+22 pages

Published
2009
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2. First Order Description of D=4 static Black Holes and the Hamilton-Jacobi equation

Author

Andrianopoli, L., D'Auria, R., Orazi, E., and Trigiante, M.

Subjects
High Energy Physics - Theory
Abstract

In this note we discuss the application of the Hamilton-Jacobi formalism to the first order description of four dimensional spherically symmetric and static black holes. In particular we show that the prepotential characterizing the flow coincides with the Hamilton principal function associated with the one-dimensional effective Lagrangian. This implies that the prepotential can always be defined, at least locally in the radial variable and in the moduli space, both in the extremal and non-extremal case and allows us to conclude that it is duality invariant. We also give, in this framework, a general definition of the ``Weinhold metric'' in terms of which a necessary condition for the existence of multiple attractors is given. The Hamilton-Jacobi formalism can be applied both to the restricted phase space where the electromagnetic potentials have been integrated out as well as in the case where the electromagnetic potentials are dualized to scalar fields using the so-called three-dimensional Euclidean approach. We give some examples of application of the formalism, both for the BPS and the non-BPS black holes., Comment: A clarifying discussion on the existence of the prepotential and a comment on multiple attractors are added; typos corrected, references added

Published
2009
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3. Attractors with Vanishing Central Charge

Author

Bellucci, S., Marrani, A., Orazi, E., and Shcherbakov, A.

Subjects
High Energy Physics - Theory
Abstract

We consider the Attractor Equations of particular $\mathcal{N}=2$, d=4 supergravity models whose vector multiplets' scalar manifold is endowed with homogeneous symmetric cubic special K\"{a}hler geometry, namely of the so-called $st^{2}$ and $stu$ models. In this framework, we derive explicit expressions for the critical moduli corresponding to non-BPS attractors with vanishing $\mathcal{N}=2$ central charge. Such formul\ae hold for a generic black hole charge configuration, and they are obtained without formulating any \textit{ad hoc} simplifying assumption. We find that such attractors are related to the 1/2-BPS ones by complex conjugation of some moduli. By uplifting to $\mathcal{N}=8$, d=4 supergravity, we give an interpretation of such a relation as an exchange of two of the four eigenvalues of the $\mathcal{N}=8$ central charge matrix $Z_{AB}$. We also consider non-BPS attractors with non-vanishing $\mathcal{Z}$; for peculiar charge configurations, we derive solutions violating the Ansatz usually formulated in literature. Finally, by group-theoretical considerations we relate Cayley's hyperdeterminant (the invariant of the stu model) to the invariants of the st^{2} and of the so-called t^{3} model., Comment: 17 pages, LaTeX file

Published
2007
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4. 'Root' Action for N=4 Supersymmetric Mechanics Theories

Author

Bellucci, S., Krivonos, S., Marrani, A., and Orazi, E.

Subjects
High Energy Physics - Theory
Abstract

We propose to consider the N=4,d=1 supermultiplet with $% (4,4,0) component content as a ``root'' one. We elaborate a new reduction scheme from the ``root'' multiplet to supermultiplets with a smaller number of physical bosons. Starting from the most general sigma-model type action for the ``root'' multiplet, we explicitly demonstrate that the actions for the rest of linear and nonlinear N=4 supermultiplets can be easily obtained by reduction. Within the proposed reduction scheme there is a natural possibility to introduce Fayet-Iliopoulos terms. In the reduced systems, such terms give rise to potential terms, and in some cases also to terms describing the interaction with a magnetic field. We demonstrate that known N=4 superconformal actions, together with their possible interactions, appear as results of the reduction from a free action for the ``root'' supermultiplet. As a byproduct, we also construct an N=4 supersymmetric action for the linear (3,4,1) supermultiplet, containing both an interaction with a Dirac monopole and a harmonic oscillator-type potential, generalized for arbitrary conformally flat metrics., Comment: 12 pages

Published
2005
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5. N=4 supersymmetric mechanics with nonlinear chiral supermultiplet

Author

Bellucci, S., Beylin, A., Krivonos, S., Nersessian, A., and Orazi, E.

Subjects
High Energy Physics - Theory
Abstract

We construct N=4 supersymmetric mechanics using the N=4 nonlinear chiral supermultiplet. The two bosonic degrees of freedom of this supermultiplet parameterize the sphere S(2) 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., Comment: 5 pages

Published
2005
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6. N=4 superconformal mechanics in the pp-wave limit

Author

Bellucci, S., Krivonos, S., and Orazi, E.

Subjects
High Energy Physics - Theory
Abstract

We constructed the pp-wave limit of N=4 superconformal mechanics with the off-shell $({\bf 3,4,1})$ 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., Comment: 11 pages. We corrected a misprint in the second pair of Eqs. (3.1)

Published
2004
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7. A Journey Through Garden Algebras

Author

Bellucci, S., Gates, S.J., Jr., Orazi, E., Beig, R., editor, Beiglböck, W., editor, Domcke, W., editor, Englert, B.-G., editor, Frisch, U., editor, Hänggi, P., editor, Hasinger, G., editor, Hepp, K., editor, Hillebrandt, W., editor, Imboden, D., editor, Jaffe, R. L., editor, Lipowsky, R., editor, Löhneysen, H. v., editor, Ojima, I., editor, Sornette, D., editor, Theisen, S., editor, Weise, W., editor, Wess, J., editor, Zittartz, J., editor, and Bellucci, Stefano, editor

Published
2006
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8. Structure and stability of traversable thin-shell wormholes in Palatini f (R) gravity

Author

Lobo, Francisco S. N., Olmo, Gonzalo J., Orazi, E., Rubiera-García, D., Rustam, A., European Commission, and Ministerio de Ciencia, Innovación y Universidades (España)

Subjects
General Relativity and Quantum Cosmology
Abstract

We study the structure and stability of traversable wormholes built as (spherically symmetric) thin shells in the context of Palatini f(R) gravity. Using a suitable junction formalism for these theories we find that the effective number of degrees of freedom on the shell is reduced to a single one, which fixes the equation of state to be that of massless stress-energy fields, contrary to the general relativistic and metric f(R) cases. Another major difference is that the surface energy density threading the thin shell, needed in order to sustain the wormhole, can take any sign and may even vanish, depending on the desired features of the corresponding solutions. We illustrate our results by constructing thin-shell wormholes by surgically grafting Schwarzschild space-times and show that these configurations are always linearly unstable. However, surgically joined Reissner-Nordström space-times allow for linearly stable, traversable thin-shell wormholes supported by a positive energy density provided that the (squared) mass-to-charge ratio, given by y=Q2/M2, satisfies the constraint 1

Published
2020

11. Structure and stability of traversable thin-shell wormholes in Palatini f (R) gravity

Author

European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Lobo, Francisco S. N., Olmo, Gonzalo J., Orazi, E., Rubiera-García, D., Rustam, A., European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Lobo, Francisco S. N., Olmo, Gonzalo J., Orazi, E., Rubiera-García, D., and Rustam, A.

Abstract

We study the structure and stability of traversable wormholes built as (spherically symmetric) thin shells in the context of Palatini f(R) gravity. Using a suitable junction formalism for these theories we find that the effective number of degrees of freedom on the shell is reduced to a single one, which fixes the equation of state to be that of massless stress-energy fields, contrary to the general relativistic and metric f(R) cases. Another major difference is that the surface energy density threading the thin shell, needed in order to sustain the wormhole, can take any sign and may even vanish, depending on the desired features of the corresponding solutions. We illustrate our results by constructing thin-shell wormholes by surgically grafting Schwarzschild space-times and show that these configurations are always linearly unstable. However, surgically joined Reissner-Nordström space-times allow for linearly stable, traversable thin-shell wormholes supported by a positive energy density provided that the (squared) mass-to-charge ratio, given by y=Q2/M2, satisfies the constraint 1

Published
2020

12. Multicenter solutions in Eddington-inspired Born–Infeld gravity

Author

European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Olmo, Gonzalo J., Orazi, E., Rubiera-García, D., European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Olmo, Gonzalo J., Orazi, E., and Rubiera-García, D.

Abstract

We find multicenter (Majumdar–Papapetrou type) solutions of Eddington-inspired Born–Infeld gravity coupled to electromagnetic fields governed by a Born–Infeld-like Lagrangian. We construct the general solution for an arbitrary number of centers in equilibrium and then discuss the properties of their one-particle configurations, including the existence of bounces and the regularity (geodesic completeness) of these spacetimes. Our method can be used to construct multicenter solutions in other theories of gravity.

Published
2020

15. New scalar compact objects in Ricci-based gravity theories

Author

Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Afonso, V.I., Olmo, Gonzalo J., Orazi, E., Rubiera-García, D., Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Afonso, V.I., Olmo, Gonzalo J., Orazi, E., and Rubiera-García, D.

Abstract

Taking advantage of a previously developed method, which allows to map solutions of General Relativity into a broad family of theories of gravity based on the Ricci tensor (Ricci-based gravities), we find new exact analytical scalar field solutions by mapping the free-field static, spherically symmetric solution of General Relativity (GR) into quadratic f(R) gravity and the Eddington-inspired Born-Infeld gravity. The obtained solutions have some distinctive feature below the would-be Schwarzschild radius of a configuration with the same mass, though in this case no horizon is present. The compact objects found include wormholes, compact balls, shells of energy with no interior, and a new kind of object which acts as a kind of wormhole membrane. The latter object has Euclidean topology but connects antipodal points of its surface by transferring particles and null rays across its interior in virtually zero affine time. We point out the relevance of these results regarding the existence of compact scalar field objects beyond General Relativity that may effectively act as black hole mimickers.

Published
2019

16. Correspondence between modified gravity and general relativity with scalar fields

Author

Ministerio de Economía y Competitividad (España), Generalitat Valenciana, Afonso, V.I., Olmo, Gonzalo J., Orazi, E., Rubiera-García, D., Ministerio de Economía y Competitividad (España), Generalitat Valenciana, Afonso, V.I., Olmo, Gonzalo J., Orazi, E., and Rubiera-García, D.

Abstract

We describe a novel procedure to map the field equations of nonlinear Ricci-based metric-affine theories of gravity, coupled to scalar matter described by a given Lagrangian, into the field equations of general relativity coupled to a different scalar field Lagrangian. Our analysis considers examples with a single and N real scalar fields, described either by canonical Lagrangians or by generalized functions of the kinetic and potential terms. In particular, we consider several explicit examples involving f(R) theories and the Eddington-inspired Born-Infeld gravity model, coupled to different scalar field Lagrangians. We show how the nonlinearities of the gravitational sector of these theories can be traded to nonlinearities in the matter fields and how the procedure allows to find new solutions on both sides of the correspondence. The potential of this procedure for applications of scalar field models in astrophysical and cosmological scenarios is highlighted.

Published
2019

17. Prevalence and progression of cardiovascular calcifications in peritoneal dialysis patients: A prospective study

Author

Gallieni M, Caputo F, Filippini A, Gabella P, Giannattasio M, Stingone A, Farina M, Amato M, Avella F, Bertoli M, Bocci C, Borgatti P, Buongiorno E, Cavatorta F, Cabiddu G, Coratelli P, Costanzo R, Daidone G, D'Angelo A, Della Grotta F, De Vecchi A, Ferrari G, Gaggiotti E, Fanciulli E, Fusaroli M, La Rosa R, Malberti F, Marinangeli G, Mauro MM, Oliva B, Orazi E, Rapisarda F, Rocca AR, Ronco C, Sacchetti A, Sasdelli M, Scanziani R, Sessa A, Spinelli C, STEFONI, SERGIO, Viglino G., Gallieni M, Caputo F, Filippini A, Gabella P, Giannattasio M, Stingone A, Farina M, Amato M, Avella F, Bertoli M, Bocci C, Borgatti P, Buongiorno E, Cavatorta F, Cabiddu G, Coratelli P, Costanzo R, Daidone G, D'Angelo A, Della Grotta F, De Vecchi A, Ferrari G, Gaggiotti E, Fanciulli E, Fusaroli M, La Rosa R, Malberti F, Marinangeli G, Mauro MM, Oliva B, Orazi E, Rapisarda F, Rocca AR, Ronco C, Sacchetti A, Sasdelli M, Scanziani R, Sessa A, Spinelli C, Stefoni S, and Viglino G.

Subjects
Adult, Male, medicine.medical_specialty, Histology, Physiology, Endocrinology, Diabetes and Metabolism, medicine.medical_treatment, Population, Left ventricular hypertrophy, Gastroenterology, Peritoneal dialysis, Young Adult, Cardiovascular calcification, PERITONEAL DIALYSIS, Internal medicine, medicine, Prevalence, CKD-MBD, Humans, Renal osteodystrophy, Prospective Studies, education, Prospective cohort study, Dialysis, CARDIOVASCULAR CALCIFICATION, Aged, Demography, Aged, 80 and over, education.field_of_study, business.industry, Calcinosis, Phosphorus, Middle Aged, medicine.disease, Survival Analysis, Surgery, Italy, Multivariate Analysis, OBSERVATIONAL STUDY, Disease Progression, SURVIVAL, Calcium, Female, Hypertrophy, Left Ventricular, Hemodialysis, business, Cardiomyopathies
Abstract

Background Patients on dialysis may have abnormal serum levels of Ca, P and parathyroid hormone, with related bone diseases. This population has an increased risk of death, with cardiovascular calcification (CC) a contributing factor. Patients on peritoneal dialysis appear to be at increased risk of hyperlipidemia, a contributing factor to atherosclerotic plaque formation. Although several studies have described the presence and progression of CC in hemodialysis populations, there are fewer data in patients on peritoneal dialysis. Study design The Renal Osteodystrophy and Calcifications: Key factors in Peritoneal Dialysis (ROCK-PD) study was a 36-month, prospective observational study conducted in Italy. The study examined the presence and progression of CC in two cardiac valves and five arterial sites. The potential associations of serum Ca and P with mortality and cardiovascular morbidity, demographic, clinical and blood chemistry variables was investigated. Results CC was present in 77% of patients at baseline ( N = 369) and in 90% of patients by study end ( N = 145), progressing in 73% of patients. There were 42 deaths (11%). Analyses showed a marked correlation between baseline P levels and the presence of left ventricular hypertrophy. However, there were no consistent correlations between serum Ca or P with mortality or morbidity. Conclusions CC was common in peritoneal dialysis patients and progressed in a majority of patients.

Published
2012

19. A peritoneal dialysis solution prepared from a three-compartment bag: biological and clinical effects

Author

Cappelli, G, Amore, A, Bandiani, G, Cancarini, Giovanni, Coppo, R, Feriani, M, Dell'Aquila, R, Saffioti, S, Spisni, C, Stingone, A, Orazi, E, Ballocchi, S, and Renaux, J. L.

Subjects
Glycation End Products, Advanced, Male, Glycosylation, Drug Storage, Apoptosis, Epithelium, Electrolytes, Peritoneal Dialysis, Continuous Ambulatory, Dialysis Solutions, In Situ Nick-End Labeling, Humans, solution, Cells, Cultured, Drug Packaging, Aged, Uremia, peritoneal dialysis, Membrane Proteins, Equipment Design, Middle Aged, No abstract available, Caspase 9, Glucose, Caspases, Female, Peritoneum, Tumor Suppressor Protein p53, Peritoneal Dialysis
Published
2000

31. Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters

Author

Locatelli, F, Mastrangelo, F, Redaelli, B, Ronco, C, Marcelli, D, Lagreca, G, Orlandini, G, Corti, M, Pontoriero, G, Difilippo, S, Rossi, R, Farma, R, Colantonio, P, Martinelli, D, Vasile, A, Allegra, V, Mengozzi, G, Martinbianco, L, Bonomini, V, Stefoni, C, Coli, L, Cianciolo, G, Desanctis, L, Deblasi, V, Alfonso, L, Rizzelli, S, Patruno, P, Brendolan, A, Crepaldi, C, Casu, Md, Mureddu, S, Maiorca, R, Cristinelli, L, Setti, G, Camerini, C, Salvadori, M, Bandini, S, Rosati, A, Mancini, G, Panzetta, G, Ianche, M, Delmastro, G, Cogoni, G, Accalai, Gp, Sechi, Ma, Alloatti, S, Paternoster, G, Gaiter, A, Manes, M, Schena, Fp, Pertosa, G, Bottalico, D, Cantafio, S, Salvo, E, Dagostino, F, Guido, A, Limido, D, Beretta, P, Vigano, Mr, Dadone, G, Verzetti, G, Navino, C, Barbe, Mc, Ruva, Ce, Amato, M, Aterini, S, Ippolito, E, Splendiani, G, Sturniolo, A, Costanzi, S, Passalacqua, S, Scatizzi, A, Dimaggio, A, Montemurro, N, Vercellone, A, Segoloni, G, Pacitti, A, Maffei, S, Scaccia, F, Fini, R, Bandiani, G, Antiga, G, Nicolini, Ma, Asproni, E, Cadinu, F, Salvietti, N, Urti, D, Lorusso, P, Dani, L, Peona, C, Filiberti, O, Porcu, Mc, Barbieri, C, Costa, S, Nicrosini, F, Mioli, V, Bibiano, L, Carletti, P, Panichi, N, Melappioni, M, Mecca, G, Mingardi, G, Perticucci, E, Huber, W, Riegler, P, Giacon, B, Altieri, P, Ferrara, R, Bolasco, Pg, Cabiddu, G, Paolillo, A, Morgante, F, Cascone, C, Deluca, M, Demin, Am, Capotorto, M, Ungaro, N, Specchio, A, Albertazzi, A, Delrosso, G, Bonomini, M, Surian, M, Bonforte, G, Dozio, B, Frizzi, V, Ciciani, Am, Ravaglia, F, Giachino, F, Bosticardo, Gm, Francisco, M, Biasioli, S, Petrosino, L, Chimienti, S, Cristofano, C, Perrone, F, Grassi, C, Orazi, E, Bisegna, S, Bracchi, O, Bazzato, G, Toffoletto, Pp, Tesio, F, Faimondi, A, Boggi, R, Campogiani, V, Gentili, F, Bolasco, F, Pistis, R, Pillosu, I, Stallone, C, Aucella, F, Procaccini, D, Avanzi, C, Sorba, G, Solinas, R, Cossu, M, Deangelis, S, Ripani, R, Piccoli, G, Martina, G, Quarello, F, Borghi, M, Massazza, M, Tagliaferri, M, Pascucci, M, Galiotta, P, Bertolucci, E, Sessa, A, Conte, F, Serbelloni, P, Virgilio, M, Delvino, A, Conte, M, Mura, C, Conti, P, Pinna, A, Neumair, F, Bonadonna, A, Stanic, L, Munaretto, G, Ciccarelli, P, Stefoni, A, Biagini, M, Gerace, Ms, Capece, R, Bordoni, E, Petroselli, F, Scaffone, V, Lombardo, V, Coppola, E, Micucci, G, Concetti, M, Capponi, E, Lisi, E, Raccosta, G, Sanna, Gm, Calvisi, L, Cherchi, Gl, Vitali, P, Castelli, P, Estivi, R, Saporiti, E, Dececco, G, Lorenzi, S, Maschio, G, Tessitore, N, Loschiavo, C, Rovati, C, Andreotti, C, Gilli, P, Depaoli, E, Natili, G, and Pensalfini, V

Subjects
medicine.medical_specialty, Beta-2 microglobulin, business.industry, medicine.medical_treatment, Synthetic membrane, Urology, Ultrafiltration, Liter, Surgery, chemistry.chemical_compound, Membrane, chemistry, Nephrology, medicine, Polysulfone, Hemodialysis, business, Dialysis
Abstract

Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters. There is increasing evidence that the biochemical and cellular phenomena induced by blood/membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications. However, there is a lack of large, prospective, randomized trials comparing biocompatible and bioincompatible membranes, and convective and diffusive treatment modalities. The primary aim of this prospective, randomized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantages (in terms of treatment tolerance, nutritional parameters and pre-treatment β 2 -microglobulin levels) over a traditional membrane (Cuprophan®). A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate (highflux hemodialysis and hemodiafiltration) offers any further advantages. Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques: Cuprophan® hemodialysis (Cu-HD), low-flux polysulfone hemodialysis (LfPS-HD), high-flux polysulfone high-flux hemodialysis (HfPS-HD), and high-flux polysulfone hemodiafiltration (HfPS-HDF). The 380 eligible patients were randomized to one of the two or four treatments (132 to Cu-HD, 147 to LfPS-HD, 51 to HfPS-HD and 50 to HfPS-HDF). The follow-up was 24 months. No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan® or with low-flux polysulfone, or among the four dialysis methods under evaluation. There was a significant decrease in pre-dialysis plasma β 2 -microglobulin levels in high-flux dialysis of 9.04 ± 10.46 mg/liter (23%) and in hemodiafiltration of 6.35 ± 12.28 mg/liter (16%), both using high-flux polysulfone membrane in comparison with Cuprophan® and low-flux polysulfone membranes (P = 0.032). The significant decrease in pre-dialysis plasma β 2 -microglobulin levels could have a clinical impact when one considers that β 2 -microglobulin accumulation and amyloidosis are important long-term dialysis-related complications.

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36. Limits for use of heparin in ionized calcium determination

Author

P. Palazzi, Filippo Quarto di Palo, Ersilia Orazi, A. Elli, Giuseppe Vezzoli, Giuseppe Bianchi, Elena Perticucci, Vezzoli, G, Elli, A, Palazzi, P, Orazi, E, Perticucci, E, di Palo, F Q, and Bianchi, G

Subjects
Calcium metabolism, Chromatography, Chemistry, Heparin, Clinical Biochemistry, Inorganic chemistry, Method, False Negative Reaction, Biological fluids, medicine, Methods, Sample Type, Humans, Chelation, Calcium, False Negative Reactions, Human, Whole blood, medicine.drug
Abstract

An important improvement in the study of calcium metabolism has been achieved by the determination of plasma ionized calcium (Ca ~) in the biological fluids by ion-selective electrodes'. Many factors can influence the measurement of Ca~: the sample type (arterial, venous whole blood or plasma), drawing details (aerobiosis or anaerobiosis), heparin type, sample storage and environmental conditions"". In this study we examine the role of chelating action of Na-heparin in whole blood Ca ~ determinations.

Published
1984

37. The self-locating catheter: Clinical experience and follow-up

Author

Teodoro Lopez, M Giannattasio, Ersilia Orazi, Pasquale Fatuzzo, Valerio Romolini, Roberto La Rosa, E. Gaggiotti, Amedeo F. De Vecchi, Roberto Bercia, Adriano Ramello, U. Buoncristiani, Alfonso Pacitti, Massimo Concetti, Giuseppe Lo Piccolo, Paola Cantù, Luigi Capotondo, Nicola Di Paolo, Giuseppe Vezzoli, Matteo Simola, Marcello Napoli, Franco Russo, Maria Cristina Tessarin, E. Sansoni, Marcello Melandri, Di Paolo, N, Capotondo, L, Sansoni, E, Romolini, V, Simola, M, Gaggiotti, E, Bercia, R, Buoncristiani, U, Canto, P, Concetti, M, De Vecchi, A, Fatuzzo, P, Giannattasio, M, La Rosa, R, Lopez, T, Lo Piccolo, G, Melandri, M, Vezzoli, G, Orazi, E, Pacitti, A, Ramello, A, Russo, F, Napoli, M, and Tessarin, Mc

Subjects
Adult, Male, Tenckhoff catheter, medicine.medical_specialty, medicine.medical_treatment, 030232 urology & nephrology, Peritonitis, Tungsten, Peritoneal dialysis, 03 medical and health sciences, Catheters, Indwelling, 0302 clinical medicine, Foreign-Body Migration, Humans, Medicine, 030212 general & internal medicine, Device Removal, Aged, business.industry, Equipment Design, General Medicine, Middle Aged, medicine.disease, Surgery, Catheter, Nephrology, Kidney Failure, Chronic, Equipment Failure, Female, Dialisis peritoneal, business, Peritoneal Dialysis, Follow-Up Studies, Kidney disease
Abstract

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.

38. Mapping nonlinear gravity into General Relativity with nonlinear electrodynamics.

Author

Afonso VI, Olmo GJ, Orazi E, and Rubiera-Garcia D

Abstract

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.

Published
2018
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39. [Switch from Darbepoetin-alpha to Epoetin-alpha: cost and efficacy comparison for haemodialytic patients over one year follow-up in a single centre].

Author

Orazi E

Subjects
Aged, Cost-Benefit Analysis, Darbepoetin alfa, Epoetin Alfa, Female, Follow-Up Studies, Humans, Male, Recombinant Proteins, Time Factors, Anemia drug therapy, Erythropoietin analogs & derivatives, Erythropoietin economics, Erythropoietin therapeutic use, Hematinics economics, Hematinics therapeutic use, Renal Dialysis
Abstract

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.

Published
2008

40. The self-locating catheter: clinical experience and follow-up.

Author

Di Paolo N, Capotondo L, Sansoni E, Romolini V, Simola M, Gaggiotti E, Bercia R, Buoncristiani U, Canto P, Concetti M, De Vecchi A, Fatuzzo P, Giannattasio M, La Rosa R, Lopez T, Lo Piccolo G, Melandri M, Vezzoli G, Orazi E, Pacitti A, Ramello A, Russo F, Napoli M, and Tessarin MC

Subjects
Adult, Aged, Device Removal, Equipment Design, Equipment Failure, Female, Follow-Up Studies, Foreign-Body Migration etiology, Humans, Kidney Failure, Chronic therapy, Male, Middle Aged, Tungsten, Catheters, Indwelling adverse effects, Peritoneal Dialysis
Abstract

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.

Published
2004

41. Low concentrations of glucose degradation products in peritoneal dialysis fluids and their impact on biocompatibility parameters: prospective cross-over study with a three-compartment bag.

Author

Cappelli G, Bandiani G, Cancarini GC, Feriani M, Dell'Aquila R, Saffioti S, Spisni C, Stingone A, Orazi E, Ballocchi S, and Renaux JL

Subjects
CA-125 Antigen analysis, Cross-Over Studies, Female, Humans, Male, Middle Aged, Prospective Studies, Biocompatible Materials, Glucose metabolism, Peritoneal Dialysis, Continuous Ambulatory
Abstract

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.

Published
1999

42. Two years of experience with a new device system: a multicenter study.

Author

Ballocchi S, Orazi E, Montanaro D, Nicolini M, Quarello F, Bonello F, Catizone L, Brunori G, Nasini MG, and Galato R

Subjects
Adult, Aged, Aged, 80 and over, Evaluation Studies as Topic, Female, Humans, Male, Middle Aged, Peritoneal Dialysis, Continuous Ambulatory adverse effects, Peritonitis etiology, Peritonitis prevention & control, Peritoneal Dialysis, Continuous Ambulatory instrumentation
Abstract

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.

Published
1995

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