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

Genotypic and phenotypic characteristics of Candida parapsilosis bloodstream isolates: Health Care Associated Infections in a teaching Hospital in Italy

Background: Candidemia is the most common healthcare associated invasive fungal infection. Over the last few decades, candidemia caused by Candida species other than Candida albicans, particularly the Candida parapsilosis complex, has emerged worldwide. The aims of this study were: to analyze the genotypic and phenotypic characteristics of C. parapsilosis strains isolated from blood cultures and the environment in a hospital in southern Italy, to study the possible source of infection and to correlate the isolated strains. Methods: From April to October 2022, cases of candidemia due to C. parapsilosis in patients admitted to a hospital in the Apulia region were investigated. However, 119 environmental samples from the intensive care unit were collected for identification of the likely environmental reservoir of infection. Routine antifungal (amphotericin B, anidulafungin, fluconazole) susceptibility was performed on all isolates. Whole genome sequencing was performed to study the genotypic correlation of the isolates. Biofilm biomass and metabolic activity were also quantified for all isolates. Results: A total of 43 C. parapsilosis isolates were cultured from the bloodstream of each patient in different departments, and seven surface samples were positive for C. parapsilosis. Most of the isolated yeasts (41/50; 85 %) were resistant to fluconazole and were genetically related to each other, suggesting an ongoing clonal outbreak of this pathogen. The fluconazole-susceptible isolates produced significantly more biofilm than did the resistant isolates. Metabolic activity was also higher for fluconazole-susceptible than resistant isolates. Conclusion: Cross-transmission of the microorganisms is suggested by the phenotypic similarity and genetic correlation between clinical and environmental strains observed in our study

Blood neurofilament light chain and S100B as biomarkers of neurological involvement and functional prognosis in COVID-19: a multicenter study

Background and aim: COVID-19 is associated with neurological complications, termed neuro-COVID, affecting patient outcomes. We aimed to evaluate the association between serum neurofilament light chain (NfL) and S100B biomarkers with the presence of neurological manifestations and functional prognosis in COVID-19 patients. Methods: A multicenter prospective cohort study was conducted in three hospitals in the Emilia-Romagna region, Italy, from March 2020 to April 2022. Hospitalized patients with PCR-confirmed COVID-19 were enrolled. Serum S100B and NfL levels were measured in the acute or subacute phase after admission. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) analyses. Statistical analyses were performed to evaluate the association between biomarkers, clinical/laboratory variables, and prognosis, specifically focusing on worsening of the modified Rankin Scale (mRS) from admission to discharge. Results: A total of 279 patients (153 males, median age 76.7 years) were included. Among them, 69 (24.7%) developed neuro-COVID. Serum NfL levels were significantly higher in the neuro-COVID group (median 110 vs 68.3; p = 0.035) and correlated with severe encephalopathy and extracranial neurologic manifestations. The ROC analysis showed low accuracy in the discrimination between the two groups for both NfL and S100B. Key predictors of worsening mRS included mechanical ventilation (OR = 9.56, 95% CI = 1.67–54.75; p = 0.011), severe encephalopathy (OR = 5.10, 95% CI = 1.58–16.19; p = 0.006), and elevated S100B levels (OR = 2.62, 95% CI = 1.10–6.46; p = 0.037). Conclusions: Serum NfL and S100B biomarkers were not accurate in discriminating neuro-COVID patients, however NfL levels were associated with severe and extracranial neuro-COVID, while S100B with functional outcomes, potentially informing clinical management

Un problema di iconografia trinitaria tra Oriente e Occidente: l'affresco di Vallepietra e le immagini di Faras (Nubia). Convergenze poligenetiche o emergenze corradicali?

Argomento di questo studio è la rappresentazione della Trinità isomorfa: si tratta di un’iconografia assai rara il cui primo esempio in ambito occidentale è costituito dall’affresco del Santuario sul Monte Autore a Vallepietra nel Lazio. L’autrice, dopo aver discusso e ribadito la datazione dell’opera al XII secolo, analizza l’origine del tema individuando in Nubia un consistente numero di testimonianze di tale iconografia, che qui si moltiplica in modo quasi esponenziale a partire dall’XI secolo. Si avanzano, infine, alcune ipotesi sia sui modelli di riferimento (forse provenienti dal mondo bizantino), sia sui possibili tramiti che hanno veicolato il tema dall’Oriente all’Occidente. This study focuses on the depiction of isomorph Trinity: that is a very rare iconography whose first occurance in Western Europe is a fresco in the Sanctuary on Mount Autore in Vallepietra (Latium). The authoress, after discussing and confirming the dating of the work of art to the 12th century, reviews the origin of that theme, picking out a considerable number of such an iconography examples in Nubia, where it increased in an exponantial way since the 11th century. Finally, some hypotheses about both the reference models (perhaps coming from the Byzantine world) and the possible ways through which the theme passed from the East to the West, are put forth