-Matrimid®5218 hollow fiber membranes were prepared using the dry-wet spinning process. The transport properties were measured with pure gases (H 2 , CO 2 , N 2 , CH 4 and O 2 ) and with a mixture (30% CO 2 and 70% N 2 ) in dry and wet conditions at 25 °C, 50 °C, 60 °C and 75 °C and up to 600 kPa. Interesting values of single gas selectivity up to 60 °C (between 31 and 28 for CO 2 /N 2 and between 33 and 30 for CO 2 /CH 4 ) in dry condition were obtained. The separation factor measured for the mixture was 20% lower compared to the single gas selectivity, in the whole temperature range analyzed. In saturation conditions the data showed that water influences the performance of the membranes, inducing a reduction of the permeance of all gases. Moreover, the presence of water caused a decrease of single gas selectivity and separation factor, although not so significant, highlighting the very high water resistance of hollow fiber membrane modules.
CO 2 /CH 4 mixtures separation was investigated using Matrimid Ò 5218 hollow fibre membranes and measuring the membrane flux feeding singly CH 4 and CO 2 and their mixtures, with CH 4 concentration ranging from 5 to 70 % molar. Specific attention was paid to membrane properties at a high temperature (up to 75°C) and feeding humidified streams, not yet particularly investigated, in a pressure range 400-600 kPa. The membrane properties were restored when water vapour was removed and temperature decreased stating the excellent hydro-thermal stability of these membranes. Maps of the separation performance were also calculated for a range of operating conditions wider than the experimental one paying specific attention to the feed/permeate pressure ratio further to membrane selectivity and permeance. Single and multistage membrane separation systems were investigated using these maps. The prepared Matrimid Ò 5218 hollow fibres showed very good performance in terms of flux and selectivity for temperatures up to 60°C, also in steam saturated conditions, allowing a methane concentration meeting the specification for its injection into the grid.
Background and Objectives.MRI connectomics is an ideal tool to test a network-based model of pathological propagation from a disease epicenter in neurodegenerative disorders. Here, we used a novel graph-theory-based MRI paradigm to explore functional connectivity reorganization, discerning between direct and indirect connections from disease epicenters, and its relationship with neurodegeneration across clinical presentations of the frontotemporal dementia (FTD) spectrum, including behavioral variant of FTD (bvFTD), non-fluent (nfvPPA) and semantic variants of primary progressive aphasia (svPPA).Methods.In this observational, cross-sectional study, disease epicenters were defined as the peaks of atrophy of a cohort of patients with high confidence of FTLD pathology (Mayo Clinic). These were used as seed regions for stepwise functional connectivity (SFC) analyses in an independent (Milan) set of FTD patients, to assess connectivity in regions directly and indirectly connected to the epicenters. Correlations between SFC architecture in healthy conditions and atrophy patterns in FTD patients were also tested.Results.As defined by comparing the 42 Mayo Clinic patients with 15 controls, disease epicenters were the left anterior insula for bvFTD, left supplementary motor area for nfvPPA, and left inferior temporal gyrus (ITG) for svPPA. Compared with 94 age-matched controls, bvFTD (n=64) and nfvPPA patients (n=34) of the Milan cohort showed widespread decreased SFC in bilateral cortical regions with direct/indirect connections with epicenters, and increased SFC either in directly connected regions, physically close to the respective seed region, or in more distant cortical/cerebellar areas with indirect connections. Across all link-steps, svPPA (n=36) showed SFC decrease mostly within the temporal lobes, with co-occurrent SFC increase in cerebellar regions at indirect link-steps. Average stepwise topological distance from the left ITG in a reference group of 50 young healthy controls correlated with regional grey matter volume in svPPA, consistent with network-based degeneration.Discussion.Our findings demonstrate that each FTD syndrome is associated with a characteristic interplay of decreased and increased functional connectivity with the disease epicenter, affecting both direct and indirect connections. SFC revealed novel insights regarding the topology of functional disconnection across FTD syndromes, holding the promise to be used to model disease progression in future longitudinal studies.
Background The aim of this study was to investigate how the COVID-19 pandemic influenced ERAS program application in colorectal surgery across hospitals in the Lazio region (central district in Italy) participating in the “Lazio Network” project. Methods A multi-institutional database was constructed. All patients included in this study underwent elective colorectal surgery for both malignant and benign disease between January 2019 and December 2020. Emergency procedures were excluded. The population was divided into 2 groups: a pre-COVID-19 group (PG) of patients operated on between February and December 2019 and a COVID-19 group (CG) of patients operated on between February and December 2020, during the first 2 waves of the pandemic in Italy. Results The groups included 622 patients in the PG and 615 in the CG treated in 8 hospitals of the network. The mean number of items applied was higher in the PG (65.6% vs. 56.6%, p < 0.001) in terms of preoperative items (64.2% vs. 50.7%, p < 0.001), intraoperative items (65.0% vs. 53.3%, p < 0.001), and postoperative items (68.8% vs. 63.2%, p < 0.001). Postoperative recovery was faster in the PG, with a shorter time to first flatus, first stool, autonomous mobilization and discharge (6.82 days vs. 7.43 days, p = 0.021). Postoperative complications, mortality and reoperations were similar among the groups. Conclusions The COVID-19 pandemic had a negative impact on the application of ERAS in the centers of the “Lazio Network” study group, with a reduction in adherence to the ERAS protocol in terms of preoperative, intraoperative and postoperative items. In addition, in the CG, the patients had worse postoperative outcomes with respect to recovery and discharge. Supplementary Information The online version contains supplementary material available at 10.1007/s00268-022-06694-8.
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