186 research outputs found

    Monitoring drying and wetting of a cement bentonite mixture with Electrical Resistivity Tomography

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    Cement bentonite slurry cutoff walls are used to encapsulate pollutants within contaminated areas, so avoiding their spreading in the environment. In both temperate and arid climates, at shallow depths, slurry walls are exposed to interaction with the atmosphere and thus to relative humidity values which might induce desaturation and significant shrinkage. This note presents the main results of a study aimed at investigating the impact of drying processes on the integrity and the hydraulic performance of cement bentonite slurry walls. Cement bentonite samples were cured under water for different times (1 months, 2 months and 4 months) and then dried naturally by exposing them to the laboratory environment (T = 21 °C, relative humidity approximately 38%). Once dried, the bottom of the samples was placed in contact with a thin layer of water to induce wetting. The distribution of the electrical conductivity within these samples was evaluated through Electrical Resistivity Tomography measurements, and electrical conductivity maps were converted then into maps of water contents on basis of a phenomenological relationship. The reconstructed water contents compared very well to the measured ones. Drying induced a limited cracking of the samples, which might affect to some extent the hydraulic performance of the barriers

    Ovarian Strumal Carcinoid: Case Report, Systematic Literature Review and Pooled Analysis

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    Background: Ovarian strumal carcinoid is a rare tumor in which thyroid (struma) and carcinoid components coexist. The disease is generally considered to be a borderline malignancy, however, cases with metastatic disease have been described. No data in the literature are available to guide diagnosis and therapy. Methods: We performed a pooled analysis and a systematic review of histopathological-confirmed strumal carcinoid cases published in the literature using the following keywords: “strumal carcinoid of the ovary”, “strumal carcinoid case report”. A case of strumal carcinoid tumor diagnosed and followed-up at the Medical Oncology Unit of Spedali Civili (Brescia, Italy) was also described and included. Results: Sixty-six eligible publications were identified, providing data from one hundred and seventeen patients, plus a case diagnosed at our institution. At presentation, among the eighty-eight patients with symptomatic disease, 37% of patients suffered from abdominal distention and 49% from pain due to a growing abdominal tumor mass, 37% from constipation (peptide YY was analyzed in only nine of them, resulting above the physiologic range). Surgery was the primary therapy in 99% of the patients. Three patients had metastatic disease at diagnosis and five patients underwent recurrence after radical surgery. Histology at disease recurrence concerned the thyroid component in two patients, the carcinoid component in two patients, both histologies in one patient. Median disease-free survival and overall survival in this series were not attained. Conclusion: Strumal carcinoid of the ovary generally presents a benign behavior and surgery is curative in most cases. However, a small group of patients with this disease can undergo disease recurrence due to both the thyroid and the neuroendocrine (carcinoid) components. A follow-up in radically operated patients is therefore needed, particularly in those with a voluminous disease at diagnosis

    Exact bounds on the ground-state energy of the infinite-U Hubbard model

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    We give upper and lower bounds for the ground-state energy of the infinite-U Hubbard model. In two dimensions, using these bounds we are able to rule out the possibility of phase separation between the undoped-insulating state and an hole-rich state.Comment: 2 pages, 1 figure, to appear in Phys. Rev.

    3D-electrical resistivity tomography monitoring of salt transport in homogeneous and layered soil samples

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    Monitoring transport of dissolved substances in soil deposits is particularly relevant where safety is concerned, as in the case of geo-environmental barriers. Geophysical methods are very appealing, since they cover a wide domain, localising possible preferential flow paths and providing reliable links between geophysical quantities and hydrological variables. This paper describes a 3D laboratory application of Electrical Resistivity Tomography (ERT) used to monitor solute transport processes. Dissolution and transport tests on both homogeneous and heterogeneous samples were conducted in an instrumented oedometer cell. ERT was used to create maps of electrical conductivity of the monitored domain at different time intervals and to estimate concentration variations within the interstitial fluid. Comparisons with finite element simulations of the transport processes were performed to check the consistency of the results. Tests confirmed that the technique can monitor salt transport, infer the hydro-chemical behaviour of heterogeneous geomaterials and evaluate the performances of clay barrier

    Limits on Phase Separation for Two-Dimensional Strongly Correlated Electrons

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    From calculations of the high temperature series for the free energy of the two-dimensional t-J model we construct series for ratios of the free energy per hole. The ratios can be extrapolated very accurately to low temperatures and used to investigate phase separation. Our results confirm that phase separation occurs only for J/t greater than 1.2. Also, the phase transition into the phase separated state has Tc of approximately 0.25J for large J/t.Comment: 4 pages, 6 figure

    Immune-related adverse events as potential surrogates of immune checkpoint inhibitors’ efficacy: a systematic review and meta-analysis of randomized studies

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    Background: Immune-related adverse events (irAEs) are frequently reported during immune checkpoint inhibitor (ICI) therapy and are associated with long-term outcomes. It is unknown if the irAE occurrence is a valid surrogate of ICIs’ efficacy. Methods: We identified articles reporting the results of randomized trials of experimental ICI therapy in solid tumors with a systematic search. The control arms could be placebo, cytotoxic/targeted therapy, or ICI therapy. We extracted the hazard ratios for overall survival (OS) with the number of OS events per arm and the number and percentages of overall and specific irAEs of grade 1-2 and grade 3-4 per arm. We estimated the treatment effect on the potential surrogate outcome with the odds ratio of the irAE rate between the experimental and the control arm. The statistical analysis consisted of weighted linear regression on a logarithmic scale between treatment effects on irAE rate and treatment effects on OS. Results: Sixty-two randomized trials were included for a total of 79 contrasts and 42 247 patients. The analyses found no significant association between the treatment effects for overall grade 1-2 or grade 3-4 irAE rates or specific (skin, gastrointestinal, endocrine) irAE rates. In the non-small-cell lung cancer (NSCLC) trial subset, we observed a negative association between treatment effects on overall grade 1-2 irAEs and treatment effects on OS in studies with patients selected for programmed death-ligand 1 expression (R2 = 0.55; 95% confidence interval 0.20-0.95; R = −0.69). In the melanoma trial subset, a negative association was shown between treatment effects on gastrointestinal grade 3-4 irAEs and treatment effects on OS in trials without an ICI-based control arm (R2 = 0.77; 95% confidence interval 0.24-0.99; R = −0.89). Conclusions: We found low-strength correlations between the ICI therapy effects on overall or specific irAE rates and the treatment effects on OS in several cancer types

    Stripe phases in the two-dimensional Falicov-Kimball model

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    The observation of charge stripe order in the doped nickelate and cuprate materials has motivated much theoretical effort to understand the underlying mechanism of the stripe phase. Numerical studies of the Hubbard model show two possibilities: (i) stripe order arises from a tendency toward phase separation and its competition with the long-range Coulomb interaction or (ii) stripe order inherently arises as a compromise between itinerancy and magnetic interactions. Here we determine the restricted phase diagrams of the two-dimensional Falicov-Kimball model and see that it displays rich behavior illustrating both possibilities in different regions of the phase diagram.Comment: (5 pages, 3 figures

    Clinical Prognostic Factors in Patients With Metastatic Adrenocortical Carcinoma Treated With Second Line Gemcitabine Plus Capecitabine Chemotherapy

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    Gemcitabine plus Capecitabine (Gem/Cape) is a frequently adopted second line chemotherapy for metastatic adrenocortical carcinoma (ACC), but only a minority of patients is destined to obtain a clinical benefit. The identification of baseline predictive factors of efficacy is relevant. We retrospectively analyzed clinical data from 50 consecutive patients with metastatic progressing ACC treated between 2011 and 2019. Patients received intravenous Gemcitabine and oral Capecitabine on a metronomic schedule. Previous mitotane therapy was maintained. Clinical benefit (partial response + stable disease) at 4 months was 30%, median progression-free survival (PFS) and disease-specific survival (DSS) from Gem/Cape start were 3 and 8 months, respectively. Among clinical variables evaluated before the start of Gem/Cape, presence of ECOG performance status ≥1 [HR 6.93 95% confidence interval (CI) 0.03–0.54, p.004] and neutrophil-to-lymphocyte ratio (NLR) ≥5 [HR 3.88, 95% (CI) 0.81–0.90, p.003] were independent indicators of poor PFS at multivariate analysis. Conversely, surgery of primary tumor, the presence of lung or lymph-node metastases, blood mitotane level, anemia, and the Advanced Lung cancer Inflammation index (ALI) failed to be independently associated. This study confirms that the Gem/Cape schedule is modestly active in heavily pretreated ACC patients (28% received at least two previous chemotherapy lines). NLR and performance status (PS) are easily available clinical parameters that are helpful to identify patients not likely to derive significant advantage from Gem/Cape chemotherapy

    Estimation of the hydraulic parameters of unsaturated samples by electrical resistivity tomography

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    In situ and laboratory experiments have shown that electrical resistivity tomography (ERT) is an effective tool to image transient phenomena in soils. However, its application in quantifying soil hydraulic parameters has been limited. In this study, experiments of water inflow in unsaturated soil samples were conducted in an oedometer equipped to perform three-dimensional electrical measurements. Reconstructions of the electrical conductivity at different times confirmed the usefulness of ERT for monitoring the evolution of water content. The tomographic reconstructions were subsequently used in conjunction with a finite-element simulation to infer the water retention curve and the unsaturated hydraulic conductivity. The parameters estimated with ERT agree satisfactorily with those determined using established techniques, hence the proposed approach shows good potential for relatively fast characterisations. Similar experiments could be carried out on site to study the hydraulic behaviour of the entire soil deposi
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