Time-reversible Dynamical Systems for Turbulence

Dynamical Ensemble Equivalence between hydrodynamic dissipative equations and suitable time-reversible dynamical systems has been investigated in a class of dynamical systems for turbulence. The reversible dynamics is obtained from the original dissipative equations by imposing a global constraint. We find that, by increasing the input energy, the system changes from an equilibrium state to a non-equilibrium stationary state in which an energy cascade, with the same statistical properties of the original system, is clearly detected.Comment: 16 pages Latex, 4 PS figures, on press on J. Phy

The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance

The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide, raising serious concerns. A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between 11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing. Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7 December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive wastewater samples rising from 1.0% (1/104 samples) in the week 5–11 December, to 17.5% (25/143 samples) in the week 12–18, to 65.9% (89/135 samples) in the week 19–25, in line with the increase in cases of infection with the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in which the variant was detected increased from one in the first week, to 11 in the second, and to 17 in the last one. The presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples, and by Sanger sequencing in 66% (64/97) of PCR amplicons. In conclusion, we designed an RT-qPCR assay capable to detect the Omicron variant, which can be successfully used for the purpose of wastewater-based epidemiology. We also described the history of the introduction and diffusion of the Omicron variant in the Italian population and territory, confirming the effectiveness of sewage monitoring as a powerful surveillance tool

The rapid spread of SARS-COV-2 Omicron variant in Italy reflected early through wastewater surveillance

The SARS-CoV-2 Omicron variant emerged in South Africa in November 2021, and has later been identified worldwide, raising serious concerns. A real-time RT-PCR assay was designed for the rapid screening of the Omicron variant, targeting characteristic mutations of the spike gene. The assay was used to test 737 sewage samples collected throughout Italy (19/21 Regions) between 11 November and 25 December 2021, with the aim of assessing the spread of the Omicron variant in the country. Positive samples were also tested with a real-time RT-PCR developed by the European Commission, Joint Research Centre (JRC), and through nested RT-PCR followed by Sanger sequencing. Overall, 115 samples tested positive for Omicron SARS-CoV-2 variant. The first occurrence was detected on 7 December, in Veneto, North Italy. Later on, the variant spread extremely fast in three weeks, with prevalence of positive wastewater samples rising from 1.0% (1/104 samples) in the week 5-11 December, to 17.5% (25/143 samples) in the week 12-18, to 65.9% (89/135 samples) in the week 19-25, in line with the increase in cases of infection with the Omicron variant observed during December in Italy. Similarly, the number of Regions/Autonomous Provinces in which the variant was detected increased from one in the first week, to 11 in the second, and to 17 in the last one. The presence of the Omicron variant was confirmed by the JRC real-time RT-PCR in 79.1% (91/115) of the positive samples, and by Sanger sequencing in 66% (64/97) of PCR amplicons. In conclusion, we designed an RT-qPCR assay capable to detect the Omicron variant, which can be successfully used for the purpose of wastewater-based epidemiology. We also described the history of the introduction and diffusion of the Omicron variant in the Italian population and territory, confirming the effectiveness of sewage monitoring as a powerful surveillance tool

Poem Versus Laparoscopic Heller Myotomy in the Treatment of Esophageal Achalasia: A Case-Control Study from Two High Volume Centers Using the Propensity Score

Background: POEM has recently had a widespread diffusion, aiming at being the treatment of choice for esophageal achalasia. The results of ongoing RCTs against laparoscopic myotomy are not available, yet. We, therefore, designed this propensity score (PS) case-control study with the aim of evaluating how POEM compares to the long-standing laparoscopic Heller myotomy + Dor fundoplication (LHD) and verifying if it may really replace the latter as the first-line treatment for achalasia. Methods: Two groups of consecutive patients undergoing treatment for primary achalasia from January 2014 to November 2017 were recruited in two high-volume centers, one with extensive experience with POEM and one with LHD. Patients with previous endoscopic treatment were included, whereas patients with previous LHD or POEM were excluded. A total of 140 patients in both centers were thus matched. LHD and POEM were performed following established techniques. The patients were followed with clinical (Eckardt score), endoscopic, and pH-manometry evaluations. Results: The procedure was successfully completed in all the patients. POEM required a shorter operation time and postoperative stay compared to LHD (p 90% for both groups (p = 0.2, Log-rank test). HR-Manometry showed a similar reduction in the LES pressure and 4sIRP; 24-h pH-monitoring showed however an abnormal exposure to acid in 38.4% of POEM patients, as compared to 17.1% of LHD patients (p < 0.01) and esophagitis was found in 37.4% of the POEM and 15.2% of LHD patients (p < 0.05). Conclusion: POEM provides the same midterm results as LHD. This study confirms, however, a higher incidence of postoperative GERD with the former, even if its real significance needs to be further evaluated. \ua9 2019, The Society for Surgery of the Alimentary Tract

Lessons learned from 227 biological meshes used for the surgical treatment of ventral abdominal defects

Purpose: The advantages of biological meshes for ventral hernia repair are still under debate. Given the high financial cost, the proper indications for biological meshes should be clarified to restrict their use to properly selected patients. Methods: A retrospective database was instituted to register all cases of abdominal wall defect treated with biological meshes from 1/2010 to 3/2016. Results: A total of 227 patients (mean age: 64 years) whose ventral abdominal defects were reconstructed with a biological mesh were included in the study. Patients were divided according to the 2010 four-level surgical-site complication risk grading system proposed by the Ventral Hernia Working Group (VHWG): Grade 1 (G1, 12 cases), Grade 2 (G2, 68 cases), Grade 3 (G3, 112 cases), and Grade 4 (G4, 35 cases). The surgical site complication rate was higher in patients with one or more risk factors (33.6% vs 19% in patients with no risk factors) (P = 0.68). Statistically significant risk factors associated with the onset of one or more postoperative surgical site complications included: diabetes, coronary artery disease, immunosuppression, and obesity. Recurrence was more common in patients with surgical site complications and mainly associated with infection (38.9%) and wound necrosis (44.4%), and in cases of inlay positioning of the mesh (36%). Conclusions: Due to their high costs, biological mesh should not be used in G1 patients. In infected fields (G4), they should only be used if no other surgical solution is feasible. There is a clear need to prospectively evaluate the performance of biological meshes. \ua9 2019, Springer-Verlag France SAS, part of Springer Nature

Wastewater surveillance of SARS-CoV-2 variants in October–November 2022 in Italy: detection of XBB.1, BA.2.75 and rapid spread of the BQ.1 lineage

This study adds insight regarding the occurrence and spread of SARS-CoV-2 Variants of Concern (VOCs) and Variants of Interest (VOIs) in Italy in October and November 2022, by testing urban wastewater collected throughout the country. A total of 332 wastewater samples were collected from 20 Italian Regions/Autonomous Provinces (APs) within the framework of national SARS-CoV-2 environmental surveillance. Of these, 164 were collected in the first week of October and 168 in the first week of November. A ∼1600 bp fragment of the spike protein was sequenced by Sanger (for individual samples) and long-read nanopore sequencing (for pooled Region/AP samples). In October, mutations characteristic of Omicron BA.4/BA.5 were detected in the vast majority (91 %) of the samples amplified by Sanger sequencing. A fraction of these sequences (9 %) also displayed the R346T mutation. Despite the low prevalence documented in clinical cases at the time of sampling, amino acid substitutions characteristic of sublineages BQ.1 or BQ.1.1 were detected in 5 % of sequenced samples from four Regions/APs. A significantly higher variability of sequences and variants was documented in November 2022, when the rate of sequences harbouring mutations of lineages BQ.1 and BQ1.1 increased to 43 %, and the number of Regions/APs positive for the new Omicron subvariant more than tripled (n = 13) compared to October. Moreover, an increase in the number of sequences with the mutation package BA.4/BA.5 + R346T (18 %), as well as the detection of variants never observed before in wastewater in Italy, such as BA.2.75 and XBB.1 (the latter in a Region where no clinical cases associated with this variant had ever been documented) was recorded. The results suggest that, as predicted by the ECDC, BQ.1/BQ.1.1 is rapidly becoming dominant in late 2022. Environmental surveillance proves to be a powerful tool for tracking the spread of SARS-CoV-2 variants/subvariants in the population