B-spline Shell Finite Element Updating by Means of Vibration Measurements

An updating procedure based on measured Frequency Response Function (FRF) data is proposed to correct the numerical parameters of a continuous B spline dynamical model of a shell structural component. Since standard FRF based parametric updating techniques may fail in practical applications because of resonance frequency shift between measured and analytical simulations, a Frequency Domain Assurance Criterion (FDAC) correlation technique was considered and included in the formulation of the objective function. Updating parameters are normalized and constrained in a compact domain by means of a proper variable transformation choice. Some real examples, concerning the model updating of a real railway bridge, is illustrated and discussed

AUTOMATIC REFINEMENT OF FE SHELL MODELS BASED ON A LOCAL ENERGY FUNCTION

ABSTRACT This paper deals with an adaptive refinement technique of a B-spline degenerate shell finite element model, for the free vibration analysis of curved thin and moderately thick-walled structures. The automatic refinement of the solution is based on an error functional related to the density of the total potential energy. The model refinement is generated by locally increasing, in a sub-domain R of a local patch domain, the number of shape functions while maintaining constant the functions polynomial order. The local refinement strategy is described in a companion paper, written by the same authors of this paper and presented in this Conference. A two-step iterative procedure is proposed. In the first step, one or more sub domains to be refined are identified by means of a point-wise error functional based on the system total potential energy local density. In the second step, the number of shape functions to be added is iteratively increased until the difference of the total potential energy, calculated on the sub domain between two iteration, is below a user defined tolerance. A numerical example is presented in order to test the proposed approach. Strengths and limits of the approach are critically discussed. INTRODUCTION Finite Element (FE) techniques are widely used for modeling the vibration behavior of industrial component and structures. Within the FE method, the infinite dimensional solution space is approximated with a finite dimensional one, consequently the obtained solution is usually approximated. In order to reduce the error, the user is usually involved in an iterative,time consuming process, in order to improve the accuracy of FE analysis results and keep low its computational cost. Efficient adaptive procedures can help users improving the accuracy of computed eigensolutions, by means of automatic, optimal, mesh refinement

Vitiligo and autoimmune thyroid disorders

Vitiligo represents the most common cause of acquired skin, hair and oral depigmentation, affecting 0.5-1% of the population worldwide. It is clinically characterized by the appearance of disfiguring circumscribed skin macules following melanocyte destruction by autoreactive cytotoxic T lymphocytes. Patients affected by vitiligo usually show a poorer quality of life and are more likely to suffer from depressive symptoms, particularly evident in dark-skinned individuals. Although vitiligo is a non-fatal disease, exposure of affected skin to UV light increases the chance of skin irritation and predisposes to skin cancer. In addition, vitiligo has been associated to other rare systemic disorders due to presence of melanocytes in other body districts, such as in the eyes, auditory, nervous and cardiac tissues, where melanocytes are thought to have roles different from that played in the skin. Several pathogenetic models have been proposed to explain vitiligo onset and progression, but clinical and experimental findings point mainly to the autoimmune hypothesis as the most qualified one. In this context, it is of relevance the strong association of vitiligo with other autoimmune diseases, in particular with autoimmune thyroid disorders, such as Hashimoto thyroiditis and Graves’ disease. In this review, after a brief overview of vitiligo and its pathogenesis, we will describe the clinical association between vitiligo and autoimmune thyroid disorders and discuss the possible underlying molecular mechanism(s)

Spontaneous gastric rupture in a 22-month-old boy: Case report and review of the literature: The diagnostic work up and management of a rare pediatric emergency

AbstractWe report the case of 22-month-old boy who sustained spontaneous gastric rupture. The patient had an episode of nausea and vomiting after a large meal the day before admission to our emergency ward. Abdominal ultrasonography revealed free and corpuscolate fluid in the abdomen. Abdominal X-ray showed free air in the abdominal cavity, leading to diagnosis of gastrointestinal perforation. Blood examination revealed metabolic acidosis. An emergency laparotomy detected a wide perforation of gastric wall involving fundus and greater curvature. A sleeve gastrectomy was performed with two layers closure of abdominal wall. Idiopathic gastric rupture, beyond neonatal period, is extremely rare in childhood. Early diagnosis and surgery are mandatory to avoid fatal complications

Cancer of the Thyroid in patients over the age of fifty.

Aim. The authors performed a retrospective investigation of patients over thè age of 50, in order to detect any peculiarities of cancer of thè thyroid possibly affecting surgical treatment and whether age itself represented an independent prognostic factor. Methods. A total of 152 patients were examined at thè Department of Surgical Science of "La Sapienza" University of Rome with a minimum follow- up of 10 years. The 152 subjects recruited were divided into 3 age groups: from 51 to 60 years, (74 patients); from 61 to 70 years, (57 patients); from 71 to 80 years, (21 patients). Resulti. Relating thè different histologic types to age group, there was found to be a lower incidence of well-differentiated carcinoma and a relative increase in thè epidermoid and undifferentiated forms in older patients. In thè 51-60 age group 80% of thè patients were at stages I and II, while in thè 71-80 age group 56.2% of cases were at stages III and IV. Conclusion. In thè elderly patient undifferentiated, anaplastic or epidermoid forms and those with a higher biologica! aggressiveness are more frequently found. We believe that prompt diagnosis would present thè surgeon with neoplasms at an early stage and with less aggressive histotypes, thus ensuring greater scope for radicai surgical treatment and appreciably enhancing prognosis

Positioning accuracy comparison of GNSS receivers used for mapping and guidance of agricultural machines

Global Navigation Satellite Systems (GNSS) allow the determination of the 3D position of a point on the Earth’s surface by measuring the distance from the receiver antenna to the orbital position of at least four satellites. Selecting and buying a GNSS receiver, depending on farm needs, is the first step for implementing precision agriculture. The aim of this work is to compare the positioning accuracy of four GNSS receivers, different for technical features and working modes: L1/L2 frequency survey-grade Real-Time Kinematic (RTK)-capable Stonex S7-G (S7); L1 frequency RTK-capable Stonex S5 (S5); L1 frequency Thales MobileMapper Pro (TMMP); low-cost L1 frequency Quanum GPS Logger V2 (QLV2). In order to evaluate the positioning accuracy of these receivers, i.e., the distance of the determined points from a reference trajectory, different tests, distinguished by the use or not of Real-Time Kinematic (RTK) differential correction data and/or an external antenna, were carried out. The results show that all satellite receivers tested carried out with the external antenna had an improvement in positioning accuracy. The Thales MobileMapper Pro satellite receiver showed the worst positioning accuracy. The low-cost Quanum GPS Logger V2 receiver surprisingly showed an average positioning error of only 0.550 m. The positioning accuracy of the above-mentioned receiver was slightly worse than that obtained using Stonex S7-G without the external antenna and differential correction (maximum positioning error 0.749 m). However, this accuracy was even better than that recorded using Stonex S5 without differential correction, both with and without the external antenna (average positioning error of 0.962 m and 1.368 m)

CTLA-4 and PD-1 ligand gene expression in epithelial thyroid cancers

The dysregulation of PD-1 ligands (PD-L1 and PD-L2) and CTLA-4 ligands (CD80 and CD86) represents a tumor strategy to escape the immune surveillance. Here, the expression of PD-L1, PD-L2, CD80 and CD86 was evaluated at mRNA level in 94 patients affected by papillary thyroid carcinoma (PTC) and 11 patients affected by anaplastic thyroid carcinoma (ATC). Variations in the mRNAs in PTC patients were then correlated with clinicopathological features. The expression of all genes was deregulated in PTC and ATC tissues compared to normal tissues. In particular, the down-regulation of CD80 was observed in above all ATC. In addition, the increased expression of CD80 associated to longer disease-free survival in PTC. Higher expression of PD-L1 associated with the classical histological variant and with the presence of BRAFV600E mutation in PTC. The increased PD-L2 expression correlated with BRAFV600E mutation and lymph node metastasis, while its lower expression correlated with the follicular PTC variant. The latter was also associated with the CD80 down-regulation, which was also related to the absence of lymph node metastasis. In conclusion, we documented the overall dysregulation of PD-1 and CTLA-4 ligands in PTC and ATC tissues and a possible prognostic value for CD80 gene expression in PTC

Blood homocysteine levels are increased in hepatocellular carcinoma patients with portal vein thrombosis. A single centre retrospective cohort study

Abstract Background Portal vein thrombosis (PVT) is reported in 10–40% of hepatocellular carcinoma (HCC) patients. The development of PVT is a multifactorial process, resulting from a reduction in portal blood flow and hypercoagulability. Methods We evaluated 44 HCC patients with PVT, 50 HCC patients without PVT and 50 healthy subjects. Homocysteine (Hcy), Vitamin B6, Vitamin B12 and folate were measured. Results Hcy in HCC patients with PVT is significant higher than the patients without PVT and controls subjects. Conclusion Total Hcy is a sensitive marker of PVT in patients with HCC

Hospitalizations for tuberculosis in Sicily over the years 2009–2021: Clinical features, comorbidities, and predictors of mortality

Background: Very few data are available in the literature regarding tuberculosis (TB) hospitalization, and few studies have reported the clinical characteristics and comorbidities of admitted patients and burden and cost of hospitalization. In our study, we described the occurrence of TB hospital admissions in the southern Italian region of Sicily over 13 years (2009–2021), explored the characteristics of patients with TB, and determined the comorbidities associated with mortality. Method: Data on the hospital discharge of all patients with TB hospitalized in all Sicilian hospitals were retrospectively collected from hospital standard discharge forms. Age, sex, nationality, length of hospital stay, comorbidities, and TB localization were evaluated using univariate analysis according to in-hospital mortality. The factors associated with mortality were included in the logistic regression model. Results: In Sicily, 3745 people were hospitalized for TB, with 5239 admissions and 166 deaths from 2009 to 2021. Most hospitalizations involved Italian-born people (46.3%), followed by African-born people (32.8%) and Eastern European-born people (14.1%). The average hospitalization cost was EUR 5259 ± 2592, with a median length of stay of 16 days (interquartile range, 8–30) days. Multivariate analysis showed that the development of acute kidney failure (adjusted odds ratio [aOR]=7.2, p < 0.001), alcohol consumption (aOR=8.9, p = 0.001), malignant tumors (aOR=2.1, p = 0.022), human immunodeficiency virus infection (aOR=3.4, p < 0.001), sepsis (aOR=15.2, p < 0.001), central nervous system involvement (aOR=9.9, p < 0.001), and miliary TB (aOR=2.5, p = 0.004) were independent predictors of mortality. Conclusion: TB in Sicily remains an important cause of hospitalization. HIV infection and comorbidities may complicate patient management and worsen patient outcomes

Nostra esperienza sul trattamento dell’ernia epigastrica

L’ernia epigastrica rappresenta una rara affezione chirurgica, talvolta insidiosa, la cui patogenesi è stata a lungo discussa, essendo stati identificati, nel corso degli anni, molteplici fattori predisponenti e responsabili della sua comparsa. Dalla nostra esperienza e dai dati ricavati dalla letteratura, si evince che non esiste per questa patologia un intervento chirurgico standard, e che oltre tutto sono spesso necessarie indagini diagnostiche preliminari non comuni, al contrario di altri difetti della parete addominale anteriore. Il nostro studio retrospettivo consiste nell’analisi dei trattamenti chirurgici eseguiti su 37 pazienti affetti da ernia epigastrica, per ognuno dei quali, sulla base delle condizioni cliniche generali, dei risultati delle indagini diagnostiche pre-operatorie e soprattutto delle caratteristiche del difetto erniario, è stato programmato un intervento chirurgico personalizzato, ottenendo così per la stessa patologia diversi protocolli di cura (procedure “open” o laparoscopiche, in ricovero ordinario o in day-surgery, riparazioni protesiche e non)