Random Assignment Problems on 2d Manifolds

We consider the assignment problem between two sets of N random points on a smooth, two-dimensional manifold Ω of unit area. It is known that the average cost scales as EΩ(N) ∼ 1 / 2 πln N with a correction that is at most of order lnNlnlnN. In this paper, we show that, within the linearization approximation of the field-theoretical formulation of the problem, the first Ω -dependent correction is on the constant term, and can be exactly computed from the spectrum of the Laplace–Beltrami operator on Ω. We perform the explicit calculation of this constant for various families of surfaces, and compare our predictions with extensive numerics

Antimicrobial activity of aztreonam in combination with old and new β-lactamase inhibitors against mbl and esbl co-producing gram-negative clinical isolates: Possible options for the treatment of complicated infections

none14noMetallo-β-lactamases (MBLs) are among the most challenging bacterial enzymes to over-come. Aztreonam (ATM) is the only β-lactam not hydrolyzed by MBLs but is often inactivated by co-produced extended-spectrum β-lactamases (ESBL). We assessed the activity of the combination of ATM with old and new β-lactamases inhibitors (BLIs) against MBL and ESBL co-producing Gram-negative clinical isolates. Six Enterobacterales and three non-fermenting bacilli co-producing MBL and ESBL determinants were selected as difficult-to-treat pathogens. ESBLs and MBLs genes were characterized by PCR and sequencing. The activity of ATM in combination with seven different BLIs (clavulanate, sulbactam, tazobactam, vaborbactam, avibactam, relebactam, zidebactam) was assessed by microdilution assay and time–kill curve. ATM plus avibactam was the most effective combination, able to restore ATM susceptibility in four out of nine tested isolates, reaching in some cases a 128-fold reduction of the MIC of ATM. In addition, relebactam and zidebactam showed to be effective, but with lesser reduction of the MIC of ATM. E. meningoseptica and C. indologenes were not inhibited by any ATM–BLI combination. ATM–BLI combinations demonstrated to be promising against MBL and ESBL co-producers, hence providing multiple options for treatment of related infections. However, no effective combination was found for some non-fermentative bacilli, suggesting the presence of additional resistance mechanisms that complicate the choice of an active therapy.openMorroni G.; Bressan R.; Fioriti S.; D'Achille G.; Mingoia M.; Cirioni O.; Di Bella S.; Piazza A.; Comandatore F.; Mauri C.; Migliavacca R.; Luzzaro F.; Principe L.; Lagatolla C.Morroni, G.; Bressan, R.; Fioriti, S.; D'Achille, G.; Mingoia, M.; Cirioni, O.; Di Bella, S.; Piazza, A.; Comandatore, F.; Mauri, C.; Migliavacca, R.; Luzzaro, F.; Principe, L.; Lagatolla, C

Side effects of antibiotics and perturbations of mitochondria functions

Antibiotics are one of the greatest discoveries of medicine of the past century. Despite their invaluable contribution to infectious disease, their administration could lead to side effects that in some cases are serious. The toxicity of some antibiotics is in part due to their interaction with mitochondria: these organelles derive from a bacterial ancestor and possess specific translation machinery that shares similarities with the bacterial counterpart. In other cases, the antibiotics could interfere with mitochondrial functions even if their main bacterial targets are not shared with the eukaryotic cells. The purpose of this review is to summarize the effects of antibiotics administration on mitochondrial homeostasis and the opportunity that some of these molecules could represent in cancer treatment. The importance of antimicrobial therapy is unquestionable, but the identification of interaction with eukaryotic cells and in particular with mitochondria is crucial to reduce the toxicity of these drugs and to explore other useful medical applications

Il viaggio disegnato. Aubin-Louis Millin nell'Italia di Napoleone (1811-1813)

Nell’autunno del 1811, all’età di cinquantadue anni, l’archeologo e storico dell’arte francese Aubin-Louis Millin (1759-1818) partì per l’Italia, realizzando un sogno da lungo tempo vagheggiato. L’itinerario attraverso la penisola, protrattosi per circa due anni, fu da lui pianificato con cura quasi ossessiva, anche grazie alle informazioni fornitegli per lettera dai suoi corrispondenti sparsi nelle diverse città e regioni italiane. Più che un viaggio di formazione di stampo settecentesco, quello di Millin fu innanzitutto un viaggio ufficiale, una missione di “inspection patrimoniale”, svolta per conto del governo francese in territori – allora ancora poco conosciuti – che erano entrati a far parte da non molti anni dell’impero napoleonico. Due erano gli obiettivi precipui dell’erudito: studiare e documentare i numerosi monuments inédits, con l’idea di dare alle stampe un nuovo voyage pittoresque della penisola; verificare attentamente le loro condizioni di conservazione, per poter segnalare alle autorità competenti tutti i casi che necessitavano di interventi di restauro. Con il suo viaggio, Millin rivoluzionò le consuetudini del Grand Tour, sia perché a essere oggetto della sua attenzione furono non solo i monumenti antichi, ma anche quelli di età medievale, rinascimentale e barocca; sia perché, sconfinando dai percorsi tradizionali, egli si inoltrò nelle regioni più periferiche e inesplorate del Regno di Napoli, quali la Calabria, la Basilicata, il Molise e l’Abruzzo. Gli imprevisti e le difficoltà del suo avventuroso periplo del Sud furono condivisi da due giovani accompagnatori: lo scrittore francese Astolphe de Custine e il pittore prussiano Franz Ludwig Catel. Quest’ultimo, in particolare, entrò in profonda sintonia con Millin, divenendo il suo «occhio», la sua antenna sensibile, sempre acuto nel registrare lo scenario artistico, antropologico e naturale delle regioni visitate. Tre sono i testi chiave per ricostruire il viaggio e il libro ne offre per la prima volta l’edizione integrale: l’Extrait del 1814, il denso diario epistolare indirizzato ai colleghi dell’Institut de France; le lettere sullo stato dei monumenti di Roma scritte nel 1812 al Ministro dell’Interno conte di Montalivet; infine l’Inventaire, un testo manoscritto con l’elenco di oltre mille disegni fatti realizzare in Italia, redatto dopo la morte dell’erudito, quando i materiali vennero acquisiti dalla Bibliothèque nationale de France (1819-1822) e andarono dispersi nelle sue raccolte. A questi documenti fondamentali vengono affiancati, oltre a un profilo intellettuale di Millin, il primo catalogo completo dei disegni eseguiti per lui da Franz Ludwig Catel e una serie di apparati e di indici ragionati, che fanno di questo volume – in coincidenza con il secondo centenario del viaggio – un’indispensabile “guida”, una sorta di Companion to Millin in Italy

Sharpening of ultrasonic sealers

Abstract Instruments suitable for removing calculus, plaque and necrotic cementum, which hinder normal periodontal reattachment, are extremely important for successful therapy. The test was carried out in order to see if a standard sealer used for ultrasonic tartar removal maintains its physical features when sharpened. 6 sealers, compatible with piezoelectric generators, were tested and 2 diameters, A and B, weights and resonance frequencies were measured. Sealers no. 2, 3, 4, 5, were sharpened with India stone, sealer no. 6 with rotatory instrument; sealer no. 1 was not sharpened and was used as control. All measurements were taken again at the end of the test. Statistical analysis reveals significant variations, after sharpening, of A diameter (t= 4.14 > 3.55, p < 0.01), B diameter (p= 5.34 > 3.355, p < 0.01) and resonance frequency (t= 2.82 > 2.306, p < 0.05); in contrast, there is no significant change of weights (t= 1.17 < 2.306, p > 0.05). These results suggest that sharpening slightly modifies the physical features of ultrasonic tips, so that sharpening ultrasonic sealers, from a physical point of view, can be carried out, paying attention not to damage the water cooling system. Copyright © 1991, Wiley Blackwell. All rights reserve