17 research outputs found

    A differential model for growing sandpiles on networks

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    We consider a system of differential equations of Monge-Kantorovich type which describes the equilibrium configurations of granular material poured by a constant source on a network. Relying on the definition of viscosity solution for Hamilton-Jacobi equations on networks, recently introduced by P.-L. Lions and P. E. Souganidis, we prove existence and uniqueness of the solution of the system and we discuss its numerical approximation. Some numerical experiments are carried out

    Survival in Patients with Primary Parotid Gland Carcinoma after Surgery—Results of a Single-Centre Study

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    This study aims to analyse a single-centre cohort series of patients who underwent parotidectomy for primary malignant parotid tumours. A retrospective chart review of 64 consecutive patients treated from November 2010 to March 2022 was performed. Outcomes were analysed by Kaplan-Meier curves. Sixty-four patients with a primary parotid malignancy were included in the study, with one bilateral case in this cohort. Patients were classified as stage I–II in 39 cases and stage III–IV in 26 cases. The five-year overall survival (OS), disease-specific survival (DSS), local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 78.4%, 89%, 92.5%, and 87.1%, respectively. Univariate analysis showed that high-risk histology, stage IV disease, lymphovascular invasion, perineural invasion, node metastasis, skin involvement, facial nerve involvement, and positive or close margins were risk factors associated with poorer outcomes. At present, the best evidence suggests that radical surgery should be the standard approach, and adjuvant therapy, in terms of radiotherapy/chemoradiotherapy, is recommended in patients with risk factors

    Idiopathic sudden sensorineural hearing loss: effectiveness of salvage treatment with intratympanic dexamethasone or hyperbaric oxygen therapy in addition to systemic steroids

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    BackgroundThe development of standardized treatments for idiopathic sudden sensorineural hearing loss (ISSNHL) is hampered by uncertainty over the etiology of this disorder. Systemic steroids are historically the primary therapy, with variable hearing outcomes. Over the last two decades, intratympanic steroids (ITS) and hyperbaric oxygen therapy (HBOT) have been proposed as salvage treatments in case of failure of systemic steroids. The present study aims to evaluate the effectiveness of these salvage treatments in addition to systemic steroids.MethodsWe performed a retrospective study on 75 consecutive patients with a diagnosis of ISSNHL who were admitted to the Department of Otorhinolaryngology of our hospital between December 2018 and December 2022. All patients received primary treatment with systemic steroids. In case of slight or no hearing recovery within the 5th day from the beginning of the therapy (T1), a salvage treatment with ITS or HBOT was proposed. Patients were divided into three groups according to the therapy received: systemic steroids (group A), systemic steroids + HBOT (group B), and systemic steroids + ITS (group C). Pure-tone average at 500, 1000, 2000, and 3000 Hz and the mean gain were evaluated at T1 and 3 months after the beginning of the salvage treatment (T2). The hearing recovery was assessed according to the Siegel's criteria.ResultsSixty-two patients (31 men and 31 women, mean age 56 years) with failure of the primary treatment were definitively enrolled in the study: 34 (54.8%) in group A, 16 (25.8%) in group B, and 12 (19.4%) in group C. The ratio of patients responding to therapy was higher in group A (29.4%) than in groups B (18.75%) and C (16.7%). We did not find any statistically significant difference between groups in terms of mean hearing gain at T2 (17.4 ± 15.4 dB in group A vs. 18.6 ± 21.1 dB in group B and 15.7 ± 14.2 dB in group C, p = 0.9).ConclusionIn our experience, ITS or HBOT associated with systemic steroids, as salvage treatment, did not show significant improvement in hearing outcomes. The evolution of ISSNHL, regardless of the treatment, remains unpredictable

    Glucorticoid receptor in human cutaneous melanoma: immunohistochemical and immunofluorescence study

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    GR is a nuclear receptor which, when activated by its specific ligand, can act as a transcription factor that binds to glucocorticoid response elements (GRE) or negative GRE. It affects inflammatory responses, differentiation and cell proliferation. The ligand activated glucocorticoid receptor induces a G1 cell cycle arrest or apoptosis in immature thymocytes and impairs proliferation of fibroblasts of undifferentiated mammary epithelial cells. It impairs proliferation and differentiation of neural progenitor cells in vivo and in vitro. Glucocorticoids are widely used in cancer therapy and have cell type-specific pro- or antiapoptotic effects. In melanoma, however, the antitumor activity of glucocorticoids remains an open question. A recent report demonstrated that in mouse embryo tissue and in human undifferentiated cells, cytoplasmic accumulation of GR is determined by nestin in conjunction with vimentin, copolymerised into an intermediate filament system, and that this anchoring of GR to the nestin/vimentin etheromeric complex is related to the maintenance of a high proliferation rate. The aim of this study was to analyse the expression of subcellular GR in cutaneous melanoma by immunofluorescence, immunohistochemistry and laser scanning confocal microscopy and to evaluate any effect in melanoma progression. The results will be discussed

    IDEAL-IQ in an oncologic population: meeting the challenge of concomitant liver fat and liver iron

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    Abstract Background Cancer patients often have a history of chemotherapy, putting them at increased risk of liver toxicity and pancytopenia, leading to elevated liver fat and elevated liver iron respectively. T1-in-and-out-of-phase, the conventional MR technique for liver fat assessment, fails to detect elevated liver fat in the presence of concomitantly elevated liver iron. IDEAL-IQ is a more recently introduced MR fat quantification method that corrects for multiple confounding factors, including elevated liver iron. Methods This retrospective study was approved by the institutional review board with a waiver for informed consent. We reviewed the MRI studies of 50 cancer patients (30 males, 20 females, 50–78 years old) whose exams included (1) T1-in-and-out-of-phase, (2) IDEAL-IQ, and (3) T2* mapping. Two readers independently assessed fat and iron content from conventional and IDEAL-IQ MR methods. Intraclass correlation coefficient (ICC) was estimated to evaluate agreement between conventional MRI and IDEAL-IQ in measuring R2* level (a surrogate for iron level), and in measuring fat level. Agreement between the two readers was also assessed. Wilcoxon signed rank test was employed to compare iron level and fat fraction between conventional MRI and IDEAL-IQ. Results Twenty percent of patients had both elevated liver iron and moderate/severe hepatic steatosis. Across all patients, there was high agreement between readers for IDEAL-IQ fat fraction (ICC = 0.957) and IDEAL R2* (ICC = 0.971) measurements, but lower agreement for conventional fat fraction measurements (ICC = 0.626). The fat fractions calculated with IOP were statistically significantly different from those calculated with IDEAL-IQ (reader 1: p < 0.001, reader 2: p < 0.001). Conclusion Fat measurements using IDEAL-IQ and IOP diverged in patients with concomitantly elevated liver fat and liver iron. Given prior work validating IDEAL-IQ, these diverging measurements indicate that IOP is inadequate to screen for hepatic steatosis in our cancer population

    Immunohistochemical analysis of angiotensin converting enzyme in sardinian pterygium

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    Pterygium is a common ocular surface disorder characterized by excessive cell proliferation, inflammation, fibrosis, angiogenesis and extracellular matrix remodeling. The Angiotensin converting enzyme (ACE or ACE I) is the major component of the Reninangiotensin system (RAS) converting the inactive decapeptide Angiotensin I (Ang I) to the active octapeptide Angiotensin II (Ang II). Besides this ‘classical role’, it can act as transcriptional regulator in response to external stimuli that may lead to cell damage and tissue remodeling. Due to this role, it can be internalized into the nuclear compartment to act as transcriptional factor for proteins involved in the inflammatory response. The aim of the present study was to determine ACE expression and localization in pterygium and culture pterygium cells by immunohistochemistry. Our results are the first to demonstrate nuclear immunolocalization of ACE, more so in pterygium compared to conjunctiva epithelial cells in histological sections. ACE was not detected in the nuclei of subcultivated pterygium epithelial cells. The nuclear localization of ACE may be correlated with an antiinflammatory path mediated by activation of its transcriptional role

    MRI liver fat quantification in an oncologic population: the added value of complex chemical shift-encoded MRI

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    Introduction: Chemotherapy prolongs the survival of patients with advanced and metastatic tumors. Since the liver plays an active role in the metabolism of chemotherapy agents, hepatic injury is a common adverse effect. The purpose of this study is to compare a novel quantitative chemical shift encoded magnetic resonance imaging (CSE-MRI) method with conventional T1-weighted In and Out of phase (T1 IOP) MR for evaluating the reproducibility of the methods in an oncologic population exposed to chemotherapy. Materials and methods: This retrospective study was approved by the institutional review board with a waiver for informed consent. The study included patients who underwent chemotherapy, no suspected liver iron overload, and underwent upper abdomen MRI. Two radiologists independently draw circular ROIsin the liver parenchyma. The fat fraction was calculated from IOP imaging and measured from IDEAL-IQ fat fraction maps. Two different equations were used to estimate fat with IOP sequences. Intra-class correlation coefficient and repeatability coefficient were estimated to evaluate agreement between two readers on iron level and fat fraction measurement. Results: CSE-MRI showed a higher reliability in fat quantification compared with both IOP methods, with a substantially higher inter-reader agreement (0.961 vs 0.372). This has important clinical implications. Conclusion: The novel CSE-MRI method described here provides increased reproducibility and confidence in diagnosing hepatic steatosis in a oncologic clinical setting. IDEAL-IQ has been proved to be more reproducible than conventional IOP imaging

    Association between the angiotensin-converting enzyme (ace) insertion/deletion (I/d) polymorphism and pterygium in sardinian patients

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    Pterygium is a common ocular surface disorder characterized by proliferation, inflammatory infiltrates, fibrosis, angiogenesis and extracellular matrix breakdown. Epidemiological studies indicate exposure chronic to UVB light as the most important risk factor for the development of pterygium. The Angiotensin Converting Enzyme (ACE) is the major component of the Renin-angiotensin system (RAS). It converts the inactive decapeptide Angiotensin I (Ang I) to the active octapeptide Angiotensin II (Ang II). Ang II is the most potent vasoconstrictor and stimulant of the aldosterone release. Recent discoveries have demonstrated that Ang II is also involved in cell proliferation, apoptosis, angiogenesis and tissue fibrosis. Moreover, it acts as growth factor and participates in inflammatory responses. The gene encoding ACE is mapped on chromosome 17q23; it contains 25 introns and 26 exons and shows a polymorphism characterized by the presence (insertion, I) or absence (deletion, D) of a 287-bp Alu sequence of DNA in intron 16. The presence or absence of Alu sequence in the ACE gene leads to the D/D, I/D and I/I genotypes. Novel studies have reported that the absence or presence of specific ACE I/D polymorphisms within ACE gene in several illnesses, such as cardiovascular diseases and breast cancer, can confer increased risk to develop the pathologies. Due to these evidences and the pterygium features, the aim of our study is to evaluate the ACE I/D gene polymorphism type in a group of Sardinia pterygium patients and to establish the possible correlation between ACE-type polymorphism and the development of pterygium in a case-control study

    Intensity Correlations in Quantum Cascade Laser Harmonic Frequency Combs

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    A novel study on harmonic frequency combs emitted by quantum cascade lasers (QCLs) is presented here, demonstrating the presence of intensity correlations between twin modes characterizing the emission spectra. These originate from a four-wave mixing process driven by the active medium's third-order nonlinearity. The study of such correlations is essential for the engineering of a new generation of semiconductor devices with the potential of becoming integrated emitters of light with quantum properties, such as squeezing and entanglement. Starting from experimental results, the limits of state-of-the-art technology are discussed as well as the possible methodologies that could lead to the detection of nonclassical phenomena, or alternatively improve the design of QCLs, in the compelling perspective of generating quantum correlations in mid-infrared light.ISSN:2699-929
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