2,382 research outputs found

    La gestione del condizionamento del terreno nello scavo meccanizzato di una galleria con TBM-EPB. Risultati di una attività sperimentale

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    Nello scavo meccanizzato di gallerie realizzato mediante l’utilizzo di TBM-EPB il corretto condizionamento del terreno assume un ruolo spesso decisivo garantendo buone e costanti performance di scavo, la corretta applicazione della pressione al fronte necessaria a contenere i cedimenti in superficie e la riduzione della usura degli utensili di scavo o di adesione del terreno a grana fine (clogging). La scelta degli agenti condizionanti è quasi sempre effettuata sulla base di esperienze pregresse mentre il corretto dosaggio viene stabilito durante il primo tratto di scavo definito di “apprendimento”; in tale tratto, partendo da dati di letteratura, da classificazioni generali e raramente da risultati di sperimentazioni in laboratorio, si modificano le modalità di iniezione degli agenti condizionanti in base alle performance di scavo registrate in tempo reale. In questa nota sono presentati i risultati di una attività sperimentale svolta su campioni di terreno a grana fine per verificare gli effetti della iniezione di differenti prodotti chimici nel terreno allo scopo di ridurre il rischio di adesione di porzioni di terreno agli utensili e alle altre parti metalliche della testa della TBM (effetto clogging). L’uso sistematico di tali prove da parte di quanti coinvolti nella gestione delle TBM prima dell’inizio delle attività di scavo, potrebbe permettere di operare una scelta più accurata dei prodotti chimici da utilizzare e di ridurre sensibilmente la fase di apprendimento limitando tempi, costi e rischi. Le stesse prove di laboratorio sono utilmente eseguite insieme ai fornitori dei prodotti chimici al fine di sviluppare nuove formule più efficaci e maggiormente rispondenti alle specifiche necessità del cantiere

    Development of a new Front End electronics in Silicon and Silicon-Germanium technology for the Resistive Plate Chamber detector for high rate experiments

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    The upgrade of the Resistive Plate Chamber (RPC) detector, in order to increase the detector rate capability and to be able to work efficiently in high rate environment, consists in the reduction of the operating voltage along with the detection of signals which are few hundred {\mu}V small. The approach chosen by this project to achieve this objective is to develop a new kind of Front End electronics which, thanks to a mixed technology in Silicon and Silicon-Germanium, enhance the detector performances increasing its rate capability. The Front End developed is composed by a preamplifier in Silicon BJT technology with a very low inner noise (1000 ee^{-} rms) and an amplification factor of 0.3-0.4 mV/fC and a new kind of discriminator in SiGe HJT technology which allows a minimum threshold of the order of 0.5 mV. The performances of this kind of Front End will be shown. The results are obtained by using the CERN H8 beamline with a full-size RPC chamber of 1 mm gas gap and 1.2 mm thickness of electrodes equipped with this kind of Front End electronics.Comment: 14th Workshop on Resistive Plate Chambers and Related Detectors 19-23 February, 2018 Puerto Vallarta, Jalisco state, Mexic

    Exploring K2G30 Genome: A High Bacterial Cellulose Producing Strain in Glucose and Mannitol Based Media

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    Demands for renewable and sustainable biopolymers have rapidly increased in the last decades along with environmental issues. In this context, bacterial cellulose, as renewable and biodegradable biopolymer has received considerable attention. Particularly, acetic acid bacteria of the Komagataeibacter xylinus species can produce bacterial cellulose from several carbon sources. To fully exploit metabolic potential of cellulose producing acetic acid bacteria, an understanding of the ability of producing bacterial cellulose from different carbon sources and the characterization of the genes involved in the synthesis is required. Here, K2G30 (UMCC 2756) was studied with respect to bacterial cellulose production in mannitol, xylitol and glucose media. Moreover, the draft genome sequence with a focus on cellulose related genes was produced. A pH reduction and gluconic acid formation was observed in glucose medium which allowed to produce 6.14 ± 0.02 g/L of bacterial cellulose; the highest bacterial cellulose production obtained was in 1.5% (w/v) mannitol medium (8.77 ± 0.04 g/L), while xylitol provided the lowest (1.35 ± 0.05 g/L) yield. Genomic analysis of K2G30 revealed a peculiar gene sets of cellulose synthase; three bcs operons and a fourth copy of bcsAB gene, that encodes the catalytic core of cellulose synthase. These features can explain the high amount of bacterial cellulose produced by K2G30 strain. Results of this study provide valuable information to industrially exploit acetic acid bacteria in producing bacterial cellulose from different carbon sources including vegetable waste feedstocks containing mannitol

    An internet-based approach for lifestyle changes in patients with NAFLD: Two-year effects on weight loss and surrogate markers

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    Background & Aims Interventions aimed at lifestyle changes are pivotal for the treatment of non-alcoholic fatty liver disease (NAFLD), and web-based programs might help remove barriers in both patients and therapists. Methods In the period 2010–15, 716 consecutive NAFLD cases (mean age, 52; type 2 diabetes, 33%) were treated in our Department with structured programs. The usual protocol included motivational interviewing and a group-based intervention (GBI), chaired by physicians, dietitians and psychologists (five weekly meetings, n = 438). Individuals who could not attend GBI entered a web-based intervention (WBI, n = 278) derived from GBI, with interactive games, learning tests, motivational tests, and mail contacts with the center. The primary outcome was weight loss ≥10%; secondary outcomes were alanine aminotransferase within normal limits, changes in lifestyle, weight, alanine aminotransferase, and surrogate markers of steatosis and fibrosis. Results GBI and WBI cohorts had similar body mass index (mean, 33 kg/m2), with more males (67% vs. 45%), younger age, higher education, and more physical activity in the WBI group. The two-year attrition rate was higher in the WBI group. Healthy lifestyle changes were observed in both groups and body mass index decreased by almost two points; the 10% weight target was reached in 20% of WBI cases vs. 15% in GBI (not significant). In logistic regression analysis, after adjustment for confounders and attrition rates, WBI was not associated with a reduction of patients reaching short- and long-term 10% weight targets. Liver enzymes decreased in both groups, and normalized more frequently in WBI. Fatty liver index was reduced, whereas fibrosis remained stable (NAFLD fibrosis score) or similarly decreased (Fib-4). Conclusion WBI is not less effective than common lifestyle programs, as measured by significant clinical outcomes associated with improved histological outcomes in NAFLD. eHealth programs may effectively contribute to NAFLD control. Lay summary In patients with non-alcoholic fatty liver disease, participation in structured lifestyle programs may be jeopardized by job and time constraints. A web-based intervention may be better suited for young, busy patients, and for those living far from liver units. The study shows that, following a structured motivational approach, a web-based, interactive intervention coupled with six-month face-to-face meetings is not inferior to a standard group-based intervention with respect to weight loss, adherence to healthy diet and habitual physical activity, normalization of liver enzymes, and stable surrogate markers of fibrosis

    Liver Transplantation for Unresectable Intrahepatic Cholangiocarcinoma: The Role of Sequencing Genetic Profiling

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    : Intrahepatic cholangiocarcinoma (iCCA) is a rare and aggressive primary liver tumor, characterized by a range of different clinical manifestations and by increasing incidence and mortality rates even after curative treatment with radical resection. In recent years, growing attention has been devoted to this disease and some evidence supports liver transplantation (LT) as an appropriate treatment for intrahepatic cholangiocarcinoma; evolving work has also provided a framework for better understanding the genetic basis of this cancer. The aim of this study was to provide a clinical description of our series of patients complemented with Next-Generation Sequencing genomic profiling. From 1999 to 2021, 12 patients who underwent LT with either iCCA or a combined hepatocellular and cholangiocellular carcinoma (HCC-iCCA) were included in this study. Mutations were observed in gene activating signaling pathways known to be involved with iCCA tumorigenesis (KRAS/MAPK, P53, PI3K-Akt/mTOR, cAMP, WNT, epigenetic regulation and chromatin remodeling). Among several others, a strong association was observed between the Notch pathway and tumor size (point-biserial rhopb = 0.93). Our results are suggestive of the benefit potentially derived from molecular analysis to improve our diagnostic capabilities and to devise new treatment protocols, and eventually ameliorate long-term survival of patients affected by iCCA or HCC-iCCA

    Intraconal tumor-like mass as first manifestation of IgG4-related disease

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    A great variety of tumors and tumor-like lesions can involve the orbit. Benign and malignant neoplasms, inflammatory diseases, vascular and congenital lesions take part of this heterogeneous group that creates many challenges for diagnosis, management, and treatment. Obviously, symptoms and clinical history are fundamental to establish a differential diagnosis, and imaging is mandatory to distinguish between lesions that have similar clinical presentations in most cases. With this report, the authors highlight the diagnostic difficulties and the importance to include not only tumors but also vascular inflammatory process into the differential diagnosis of this unilateral orbital lesion type

    Clinical and Molecular-Based Approach in the Evaluation of Hepatocellular Carcinoma Recurrence after Radical Liver Resection

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    Background: Hepatic resection remains the treatment of choice for patients with early-stage HCC with preserved liver function. Unfortunately, however, the majority of patients develop tumor recurrence. While several clinical factors were found to be associated with tumor recurrence, HCC pathogenesis is a complex process of accumulation of somatic genomic alterations, which leads to a huge molecular heterogeneity that has not been completely understood. The aim of this study is to complement potentially predictive clinical and pathological factors with next-generation sequencing genomic profiling and loss of heterozygosity analysis. Methods: 124 HCC patients, who underwent a primary hepatic resection from January 2016 to December 2019, were recruited for this study. Next-generation sequencing (NGS) analysis and allelic imbalance assessment in a case-control subgroup analysis were performed. A time-to-recurrence analysis was performed as well by means of Kaplan-Meier estimators. Results: Cumulative number of HCC recurrences were 26 (21%) and 32 (26%), respectively, one and two years after surgery. Kaplan-Meier estimates for the probability of recurrence amounted to 37% (95% C.I.: 24-47) and to 51% (95% C.I.: 35-62), after one and two years, respectively. Multivariable analysis identified as independent predictors of HCC recurrence: hepatitis C virus (HCV) infection (HR: 1.96, 95%C.I.: 0.91-4.24, p = 0.085), serum bilirubin levels (HR: 5.32, 95%C.I.: 2.07-13.69, p = 0.001), number of nodules (HR: 1.63, 95%C.I.: 1.12-2.38, p = 0.011) and size of the larger nodule (HR: 1.11, 95%C.I.: 1.03-1.18, p = 0.004). Time-to-recurrence analysis showed that loss of heterozygosity in the PTEN loci (involved in the PI3K/AKT/mTOR signaling pathway) was significantly associated with a lower risk of HCC recurrence (HR: 0.35, 95%C.I.: 0.13-0.93, p = 0.036). Conclusions: multiple alterations of cancer genes are associated with HCC progression. In particular, the evidence of a specific AI mutation presented in 20 patients seemed to have a protective effect on the risk of HCC recurrence
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