631 research outputs found

    A quasi-static nonlinear analysis for assessing the fire resistance of 3d frames exploiting time-dependent yield surface

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    In this work an automatic procedure for evaluating the axial force-biaxial bending yield surface of reinforced concrete sections in fire is proposed. It provides an accurate time-dependent expression of the yield condition by a section analysis carried out once and for all, accounting for the strength reduction of the materials, which is a function of the fire duration. The equilibrium state of 3D frames with such yield conditions, once discretized using beam finite elements, is formulated as a nonlinear vectorial equation defining a curve in the hyperspace of the discrete variables and the fire duration. A generalized path-following strategy is proposed for tracing this curve and evaluating, if it exists, the limit fire duration, that is the time of exposure which leads to structural collapse. Compared to the previous proposals on the topic, which are limited to local sectional checks, this work is the first to present a global analysis for assessing the fire resistance of 3D frames, providing a time history of the fire event and taking account of the stress redistribution. Numerical examples are given to illustrate and validate the proposal

    Local boundedness for solutions of a class of nonlinear elliptic systems

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    In this paper we are concerned with the regularity of solutions to a nonlinear elliptic system of m equations in divergence form, satisfying p growth from below and q growth from above, with p <= q; this case is known as p, q-growth conditions. Well known counterexamples, even in the simpler case p = q, show that solutions to systems may be singular; so, it is necessary to add suitable structure conditions on the system that force solutions to be regular. Here we obtain local boundedness of solutions under a componentwise coercivity condition. Our result is obtained by proving that each component u(alpha) of the solution u = (u(1),..., u(m)) satisfies an improved Caccioppoli's inequality and we get the boundedness of u(alpha) by applying De Giorgi's iteration method, provided the two exponents p and q are not too far apart. Let us remark that, in dimension n = 3 and when p = q, our result works for 3/2 < p <= 3, thus it complements the one of Bjorn whose technique allowed her to deal with p <= 2 only. In the final section, we provide applications of our result

    On the H\uf6lder continuity for a class of vectorial problems

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    In this paper we prove local H\uf6lder continuity of vectorial local minimizers of special classes of integral functionals with rank-one and polyconvex integrands. The energy densities satisfy suitable structure assumptions and may have neither radial nor quasi-diagonal structure. The regularity of minimizers is obtained by proving that each component stays in a suitable De Giorgi class and, from this, we conclude about the H\uf6lder continuity. In the final section, we provide some non-trivial applications of our results

    Laparoscopic Gastric Sleeve and Micronutrients Supplementation: Our Experience

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    Background. Laparoscopic gastric sleeve (LGS) has been recently introduced as a stand-alone, restrictive bariatric surgery. Theoretically, LGS attenuates micronutrients deficiencies and associated complications that were typically observed following malabsorptive procedures. The aim of this study was to assess some micronutrients and mineral deficiencies in patients undergoing LGS. Methods. In the period between July 2008 and April 2010, 138 obese patients (110 females and 28 males) with mean BMI 44.4 kg/m2 ± 6.5, mean age 43.9 ± 10.9 years were enrolled and underwent LGS. Patients were followed up with routine laboratory tests and anthropometric measurements and assessed for nutritional status, as regards vitamin B12, folic acid, iron, hemoglobin, calcium, and vitamin D, every three months throughout 12 months. Results. 12 months after sleeve, patients did not show iron deficiency and/or anemia; plasma calcium levels were in the normal range without supplementation from the sixth month after the operation. Vitamin B12 and folic acid were adequately supplemented for all the follow-up period. Vitamin D was in suboptimal levels, despite daily multivitamin supplementation. Conclusion. In this study, we showed that LGS is an effective surgery for the management of morbid obesity. An adequate supplementation is important to avoid micronutrients deficiencies and greater weight loss does not require higher dosage of multivitamins

    Modulating Tumor Microenvironment: A Review on STK11 Immune Properties and Predictive vs Prognostic Role for Non-small-cell Lung Cancer Immunotherapy

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    The quest for immunotherapy (IT) biomarkers is an element of highest clinical interest in both solid and hematologic tumors. In non-small-cell lung cancer (NSCLC) patients, besides PD-L1 expression evaluation with its intrinsic limitations, tissue and circulating parameters, likely portraying the tumor and its stromal/immune counterparts, have been proposed as potential predictors of IT responsiveness. STK11 mutations have been globally labeled as markers of IT resistance. After a thorough literature review, STK11 mutations condition the prognosis of NSCLC patients receiving ICI-containing regimens, implying a relevant biological and clinical significance. On the other hand, waiting for prospective and solid data, the putative negative predictive value of STK11 inactivation towards IT is sustained by less evidence. The physiologic regulation of multiple cellular pathways performed by STK11 likely explains the multifaceted modifications in tumor cells, stroma, and tumor immune microenvironment (TIME) observed in STK11 mutant lung cancer, particularly explored in the molecular subgroup of KRAS co-mutation. IT approaches available thus far in NSCLC, mainly represented by anti-PD-1/PD-L1 inhibitors, are not promising in the case of STK11 inactivation. Perceptive strategies aimed at modulating the TIME, regardless of STK11 status or specifically addressed to STK11-mutated cases, will hopefully provide valid therapeutic options to be adopted in the clinical practice

    Optonongenetic enhancement of activity in primary cortical neurons

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    It has been recently demonstrated that the exposure of naive neuronal cells to light—at the basis of optogenetic techniques and calcium imaging measurements—may alter neuronal firing. Indeed, understanding the effect of light on nongenetically modified neurons is crucial for a correct interpretation of calcium imaging and optogenetic experiments. Here we investigated the effect of continuous visible LED light exposure (490 nm, 0.18−1.3 mW/mm2) on spontaneous activity of primary neuronal networks derived from the early postnatal mouse cortex. We demonstrated, by calcium imaging and patch clamp experiments, that illumination higher than 1.0 mW/mm2 causes an enhancement of network activity in cortical cultures. We investigated the possible origin of the phenomena by blocking the transient receptor potential vanilloid 4 (TRPV4) channel, demonstrating a complex connection between this temperature-dependent channel and the measured effect. The results presented here shed light on an exogenous artifact, potentially present in all calcium imaging experiments, that should be taken into account in the analysis of fluorescence data

    Inflammatory Related Reactions in Humans and in Canine Breast Cancers, A Spontaneous Animal Model of Disease

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    Inflammatory cells are emerging markers in various cancers in human trials. The relationship between the inflammatory cells response, cancer grade, and progression has been investigated experimentally in a spontaneous canine model of breast cancer and in the unselected population (18–64 years.o.) under anti-HER2 treatments that represent the most prevalent population in this cancer type. The canine data (N samples = 101) were collected retrospectively for diagnosis in our regional area and evaluated by immunohistochemistry and haemato-chemistry. The inflammatory and immune-related adverse reactions (ADR) in humans were evaluated using EudraVigilance. The “Proportional Reporting Ratio” (PRR) of the mabs was calculated for each ADR with values >2 indicative of high risk. In dogs, we found elevated immunostaining of CD68-macrophages in the lymph node of the aggressive cancer G3 and infiltrating CD20+-lymphocyte. A high density of CD20 + lymphocytes was observed in G1 and a decrease in the density was observed with the histological degree of the tumors. The animals with the sample in G1 showed reduced serum platelet and neutrophil count and elevated lymphocytes and the opposite in severely affected animals. Inflammatory reactions with edema, skin reactions, extravasation, loss of effectiveness, and platelet count decrease (PRR > 13) were found with trastuzumab emtansine in humans, in the absence of immune system reactions. Trastuzumab i.v.-s.c. showed immune system reactions, loss of effectiveness, intolerances with drug withdrawal, technological issues (PRR > 7), and neutrophil count decrease reports. These reactions were less frequently reported for pertuzumab i.v. Case reports of platelet and neutrophil count decrease were not associated with disease progression with a better outcome in humans as in canine breast cancer. Therefore, infiltrating CD68-macrophages are associated with G3, while infiltrating CD20+ and elevated serum lymphocytes in parallel with reduced platelet and neutrophil count play a favorable role in human and canine breast cancer
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