Università degli Studi di Palermo
Recent publications
Tumor invasion follows a complex mechanism which involves cell migration and proliferation. To study the processes in which primary and secondary metastases invade and damage the normal cells, mathematical models are often extremely useful. In this manuscript, we present a mathematical model of acid-mediated tumor growth consisting of radially symmetric reaction-diffusion equations. The assumption on the radial symmetry of the solutions is imposed here in view that tumors present spherical symmetry at the microscopic level. Moreover, we consider various empirical mechanisms which describe the propagation of tumors by considering cancer cells, normal cells, and the concentration of H + ions. Among other assumptions, we suppose that these components follow logistic-type growth rates. Evidently, this is an important difference with respect to various other mathematical models for tumor growth available in the literature. Moreover, we also add competition terms of normal and tumor cells growth. We carry out a balancing study of the equations of the model, and a numerical model is proposed to produce simulations. Various practical remarks derived from our assumptions are provided in the discussion of our the simulations. Response to Reviewers: % In LaTeX format. Please, compile the file. \documentclass[letterpaper,10pt]{article} \usepackage{color} \usepackage{amssymb} \setlength{\leftmargini}{0.3in} % \setlength{\parindent}{0.5in} % \setlength{\topmargin}{-0.75in} % Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation
The aim of the paper is to study a Dirichlet problem whose equation is driven by a degenerate p-Laplacian with a weight depending on the solution and whose reaction is a convection term, thus depending on the solution and its gradient. The existence of a weak solution is proven by arguing through a truncated auxiliary problem. A major part of the proof consists in showing that the solutions are bounded.
Dynamic vibration control devices provided with inertance, such as Tuned Inerter Dampers, Tuned Mass Damper Inerters or Tuned Liquid Column Damper Inerters, have been shown in numerous numerical studies to have superior vibration mitigation performance compared to conventional devices, such as Tuned Mass Dampers. One possible way to produce this inertance effect is by means of a moving fluid. In this study, the dynamic performance of such a fluid inerter is analyzed experimentally. The considered small-scale prototype consists of a hydraulic cylinder, and the inertance is generated by the flow of the working fluid in an external channel attached to the cylinder itself. In a first step, the dry configuration, i.e. without fluid, is investigated, revealing a nonlinear dissipation force. In a corresponding mechanical model, this force is represented by a variant of the well-known Stribeck effect. Subsequent experiments on the complete configuration, i.e. with fluid, reveal a further nonlinear effect. This effect is attributed to the compressibility of the working fluid as well as air trapped in the channel. Once the parameters of the mechanical model are retrieved, comparative studies are carried out. These show a remarkable agreement between numerical and experimental outcomes, thus enabling the mechanical model to be used in dynamic vibration control devices, as stated above.
Different types of adaptive tuned mass dampers have been recently proposed in the literature. One of the most promising approaches to make tuned mass dampers adaptive is the use of shape memory alloys. In this class of tuned mass dampers, different layouts have been proposed. This paper aims at comparing the two main layouts (wire-based and beam-based) in terms of adaptation capability, exerted force and electrical power consumption. To this purpose, the models of the two layouts are developed. These models minimise the number of required inputs, which basically are only related to device geometry, shape memory alloy characteristics, and vibration input. After an experimental validation, the models are employed for the mentioned comparisons between the two considered layouts.
Integral Severe Accident (SA) codes are aimed at providing an exhaustive coverage of all the main phenomena taking place in a core melt accident. Today, these deterministic codes have reached a high level of maturity for the simulation of operating reactors and the nuclear technical community is starting to extend their applicability to advanced reactor designs, as Small Modular Reactor (SMR). In the framework of the NUGENIA TA-2 ASCOM (ASTEC COMmunity) collaborative project, a generic input-deck based on the IRIS design has been developed for the ASTEC code. The generic SMR ASTEC model has been already proved able to simulate the main thermal–hydraulic phenomena driving the passive mitigation of a SBLOCA in Design Basis Accident (DBA) conditions. The same initiator event, regarding the guillotine break of a Direct Vessel Injection (DVI) line, will be assumed for the simulation of beyond-design scenarios by considering the unavailability of selected passive safety systems. The results of the ASTEC simulations of four Beyond Design Basis Accidents (BDBAs) (study carried out with ASTEC V2.2, IRSN all rights reserved, [2021]) will be analyzed and discussed against the reference DBA sequence in the present paper. This study is aimed at proving the first insights about the capability of the ASTEC model of a generic IRIS reactor to be used in BDBA and in SA analyses, if significant core degradation takes place. In addition, it characterizes the role played by each safety system in SMR passive mitigation strategy and give the possibility to characterize the phenomenologies specific of SMR designs.
Pharmaceutical and personnel care products (PPCPs) from wastewater are a potential hazard to the human health and wildlife, and their occurrence in wastewater has caught the concern of researchers recently. To deal with PPCPs, various treatment technologies have been evolved such as physical, biological, and chemical methods. Nevertheless, modern and efficient techniques such as advance oxidation processes (AOPs) demand expensive chemicals and energy, which ultimately leads to a high treatment cost. Therefore, integration of chemical techniques with biological processes has been recently suggested to decrease the expenses. Furthermore, combining ozonation with activated carbon (AC) can significantly enhance the removal efficiency. There are some other emerging technologies of lower operational cost like photo-Fenton method and solar radiation-based methods as well as constructed wetland, which are promising. However, feasibility and practicality in pilot-scale have not been estimated for most of these advanced treatment technologies. In this context, the present review work explores the treatment of emerging PPCPs in wastewater, via available conventional, non-conventional, and integrated technologies. Furthermore, this work focused on the state-of-art technologies via an extensive literature search, highlights the limitations and challenges of the prevailing commercial technologies. Finally, this work provides a brief discussion and offers future research directions on technologies needed for treatment of wastewater containing PPCPs, accompanied by techno-economic feasibility assessment.
This paper investigates how to step up local image descriptor matching by exploiting matching context information. Two main contexts are identified, originated respectively from the descriptor space and from the keypoint space. The former is generally used to design the actual matching strategy while the latter to filter matches according to the local spatial consistency. On this basis, a new matching strategy and a novel local spatial filter, named respectively blob matching and Delaunay Triangulation Matching (DTM) are devised. Blob matching provides a general matching framework by merging together several strategies, including rank-based pre-filtering as well as many-to-many and symmetric matching, enabling to achieve a global improvement upon each individual strategy. DTM alternates between Delaunay triangulation contractions and expansions to figure out and adjust keypoint neighborhood consistency. Experimental evaluation shows that DTM is comparable or better than the state-of-the-art in terms of matching accuracy and robustness. Evaluation is carried out according to a new benchmark devised for analyzing the matching pipeline in terms of correct correspondences on both planar and non-planar scenes, including several state-of-the-art methods as well as the common SIFT matching approach for reference. This evaluation can be of assistance for future research in this field.
In this paper, we study the quasilinear elliptic problem −Δpu=au+p−1−bu−p−1inΩ,u=constanton∂Ω,0=∫∂Ω|∇u|p−2∇u⋅νdσ,where the operator is the p-Laplacian and the boundary condition is of type no-flux. In particular, we consider the Fučík spectrum of the p-Laplacian with no-flux boundary condition which is defined as the set Πp of all pairs (a,b)∈R2 such that the problem above has a nontrivial solution. It turns out that this spectrum has a first nontrivial curve C being Lipschitz continuous, decreasing and with a certain asymptotic behavior. Since (λ2,λ2) lies on this curve C, with λ2 being the second eigenvalue of the corresponding no-flux eigenvalue problem for the p-Laplacian, we get a variational characterization of λ2. This paper extends corresponding works for Dirichlet, Neumann, Steklov and Robin problems.
Some limit theorems of the type∫Ωfndmn→∫Ωfdm are presented for scalar, (vector), (multi)-valued sequences of mn-integrable functions fn. The convergences obtained, in the vector and multivalued settings, are in the weak or in the strong sense.
The cultivated hops are recently moving towards new growing areas in Southern Europe, boosted by the increasing number of craft breweries and by the higher vulnerability to climate change observed, for this crop, in the traditional growing regions. Despite this clear market and geographic trend, there is a lack of knowledge about pedoclimatic needs and agronomic performances of hops grown in the Mediterranean environment. Particularly, the agronomic potential of a new hopyard during its establishment period is poorly studied even in traditional growing zones. Moreover, a restricted number of plants were usually sampled to gather the few data available, thus leading to a probable overestimation of yield performance. A commercial organic hopyard in central Italy was established and a 2-year (2018–2019) field experiment was set-up to accurately investigate the cone and shoot yield potential of cultivar ‘Cascade’ and to understand how such yields are related to each other and to soil texture. Hop plants were two-years old when the experiment started; plant population was 4,000 plants ha⁻¹. Forty points within the hopyard were sampled for soil analysis and yield traits. Data were analyzed accounting for spatial dependence of the sampling points. Results show a negative relation between clay content in the soil and hop yields, even though it was significant only in the exceptional rainy season of 2018. Shoot and cone yield were positively and strongly related, suggesting the green shoot yield in spring as a good predictor of hop production. Both shoot and cone yield significantly increased from the second to the third year (+11% and +16%, respectively); however, the unseasonably high rainfall of 2018 probably lowered the yield of the first experimental year. Cone yield attained over this 2-year study (1.24 t ha⁻¹ and 1.44 t ha⁻¹ for 2018 and 2019, respectively) was within the published ranges for mature plants. Similarly to cone production, shoot dry matter yield was lower in 2018 (197 kg ha⁻¹) than in 2019 (218 kg ha⁻¹). This study provides the first reliable information on both cone and shoot yield potential of a young organic hopyard under Mediterranean climatic conditions.
SARS-CoV-2 infection has been a major threat to human health and a huge challenge to Medicine. In only two years, COVID-19 affected >350 million people, causing >5.6 million deaths. Chronic inflammatory states, such as diabetes or obesity, are known risk factors for COVID-19 poorest outcomes, with higher risk for disease severity and greater mortality. Metformin remains on the first line of the management of hyperglycemia in type 2 diabetes. Through its anti-inflammatory and immunomodulatory mechanisms, metformin appears as an opportunity to control the dysregulated cytokine storm secondary to SARS-CoV-2 infection. Recent studies point towards a potential protective role of metformin in the course of COVID-19, showing that current or previous treatment with metformin associates with better outcomes.
Evaluation of Cannabis consumption is required for many purposes (i.e., workplace drug testing and driving license renewal). Hair analysis represents the most adopted and reliable approach for the investigation of repeated or chronic exposure to Cannabis. The main markers are the Δ9-tetrahydrocannabinol (THC) and its main metabolite, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), as stated by the Society of Hair Testing (SoHT) and the European Workplace Drug Testing Society (EWDTS). In this paper we presented an observational study on the hair concentrations of THC and THC-COOH and influences due to age, gender, consumption habits, and hair features. Data were collected from analysis of scalp hair samples (3-cm proximal segment) provided by subjects tested for THC consumption for personal purposes (i.e., workplace drug testing, personal use proving). The subjects provided an informed consent and a short questionnaire. A new analytical method was previously developed and then adopted. It consisted in a hydrolysis (1 mL of 1 M NaOH at 65 °C, 20 min) and a liquid-liquid extraction (with hexane/ethyl acetate,90/10, v/v in presence of 1.5 mL of H2SO4 1 M) of 25 mg of hair. A liquid chromatograph - tandem mass spectrometer (LC-MS/MS) equipped with a C18 column was used. The acquisition was in multiple reaction monitoring for the following transitions: 315→259, 193 m/z, for THC; 318→196, 123 m/z, for THC-d3; 345→299, 193 m/z for THC-COOH; 348→196, 302 m/z for THC-COOH-d3. Correlation between THC and THC-COOH hair concentrations was analyzed by Spearman's rank correlation coefficient. In order to study the influences of several variables, a new value, Sqrt(THC*THCCOOH), was adopted. Its effectiveness and reliability were proved by the Principal Component Analysis. Relationships between the Sqrt(THC*THCCOOH) and the variables were studied through the Stepwise regression (p = 0.05). The normality of data distribution was tested by the Shapiro-Wilk test. The Lower limits of quantification were 10.0 (THC) and 0.2 (THC-COOH) pg/mg. Accuracy and precision always met the acceptable criteria. Recoveries were > 78% and ion suppression was observed for both the compounds. Data from 126 hair samples were included in this study: 54 subjects(42.9%) were positive both for THC and THC-COOH; none of the samples was positive for a single substance. Concentrations ranged from 0.18 to 1.75 ng/mg (median: 0.78 ng/mg) for THC and from 0.04 to 0.85 ng/mg (median: 0.31 ng/mg) for THC-COOH. Cannabinoids levels seemed to decrease with the age, with lower amounts in the subjects aged > 40 years (p < 0.05). Also years of consumption seemed to have a significant impact on hair concentrations, as higher levels were observed in consumers from > 10 years (p = 0.013). Moreover, this study further provided evidences of a significant reduction of THC and THC-COOH in bleached hair (p = 0.042).
This study examines the effects of government spending shocks on the Italian credit market using NUTS 3 data over the sample period 2011–2018. The empirical methodology is based on a local projection IV and the identification of a public spending shock is achieved by constructing a Bartik instrument. The empirical evidence shows a mild positive effect of 1% increase in government spending relative to GDP on the growth of the volume loans relative to GDP. However, the empirical findings show that government spending does not help to ameliorate neither the “size bias,” that is the financial constraints which small firms face relative to larger ones, nor the “home bias” in lending related to the process of bank consolidation in Italy.
The growing amount of evidence suggests the existence of a bidirectional relation between coronavirus disease 2019 (COVID-19) and type 2 diabetes mellitus (T2DM), as these two conditions are worsening each other, causing a significant healthcare and socioeconomic burden. The alterations in innate and adaptive cellular immunity, adipose tissue, alveolar, and endothelial dysfunction, hypercoagulation, propensity to an increased viral load, and chronic diabetic complications are all associated with glucometabolic perturbations characteristic for T2DM patients, and predispose them to severe forms and mortality of COVID-19. On the other hand, severe acute respiratory syndrome coronavirus 2 infection negatively impacts glucose homeostasis due to its effects on insulin sensitivity and β-cell function, further aggravating the preexisting glucometabolic perturbations in individuals with T2DM. Thus, we are in the urgent need for the most effective ways of countering these glucometabolic disturbances occurring during the acute COVID-19 illness in T2DM patients. The novel classes of antidiabetic medications (dipeptidyl peptidase 4 inhibitors (DPP-4is), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), and sodium-glucose co-transporter-2 inhibitors (SGLT-2is) are considered as candidate drugs for this purpose. The aim of this review article was to summarize current knowledge regarding the glucometabolic disturbances during acute COVID-19 illness in T2DM patients and the potential ways to tackle those using novel antidiabetic medications. Recent observational data suggest that preadmission use of GLP-1 RAs and SGLT-2is are associated with a decreased, while the preadmission use of DPP-4is is associated with an increased in-hospital mortality of T2DM patients with COVID-19. Although these results provide further evidence for the widespread use of these two classes of medications in the COVID-19 era, dedicated randomized controlled trials analyzing the effects of in-hospital use of novel antidiabetic agents in T2DM patients with COVID-19 are needed.
In semiarid environments of the Mediterranean region, intercropping is a sustainable agricultural system of long standing. In this area, the pea (Pisum sativum L.) is one of the most commonly grown legume crops. Little information is available on the quality of silages to be obtained from forage mixtures of pea intercropped with cereals or annual grasses. In this study, two experiments were conducted over the course of two growing seasons in Sicily (Italy) with the aims to determine the biomass production of forage crop mixtures and assess, only in the second experiment, the silage quality of grass and legumes. Four cereals and one annual grass species were grown in pure stand and in mixture with pea, and their main agronomic traits were determined. The land equivalent ratio (LER), competitive ratio, and aggressivity index were also calculated. A number of parameters were considered to assess the quality of silage obtained from fermented biomasses derived from pea‐ryegrass (Lolium multiflorum Lam. var. Westerwoldicum) intercropping. In the first experiment, the best performance between the intercrops was recorded for the pea‐wheat mixture. The total LER calculated for fodder yields was always greater than 1, indicating crop yield advantages ranging from 2.0% to 47.0%. In the second experiment, the pea‐ryegrass mixture appeared to respond well, depending on plant arrangement and seeding ratio factors: the ratios 50:50 and 100:50 showed the greatest crop yield advantages, of 12.0% and 11.0%, respectively. All silages revealed a very good suitability of a pea‐ryegrass intercropping system with high‐quality silage production in the Southern Mediterranean region. This article is protected by copyright. All rights reserved Intercrops represent a key strategy to increase the sustainability of forage production in Sicily. Legumes in forage mixtures provide potential benefits to soil fertility and fodder quality for livestock feeding. Plant arrangement and seeding ratio should be jointly assessed to maximize yield and pea‐ryegrass silages’ quality. Pea‐ryegrass intercrop is very suitable for quality silage production in the Southern Mediterranean regions.
Introduction Physiological heart adaptations may lead to increased susceptibility to arrhythmia in athletes. Furthermore, vigorous training and method like rapid weight loss (RWL) in combat sports could pose additional risks. This case represents how routine cardiovascular screening during high-risk methods like RWL and high-intensity training (HIT) reveal abrupt ventricular arrhythmias in a young athlete. Case report We report a case of a 20-year-old male wrestler athlete who developed disrupting arrhythmia during RWL and HIT. The study included: a medical exam, 12 lead electrocardiograms (ECG), transthoracic echocardiogram (ECHO), and 24 h of continuous ECG monitoring in baseline, phase one (P1), (in which the athlete had to simulate RWL through vigorous training and dietary intervention and HIT) and phase two (P2), (with the same HIT protocol performed without the RWL procedure). Baseline laboratory analyses were without abnormalities, ECG showed sinus rhythm with one premature atrial contraction (PAC) and ECHO showed signs of concentric remodeling with preserved systolic, diastolic function, and global longitudinal strain. After P1 RWL simulation, he lost 5.15% of body weight in 3 days, which resulted in lower blood glucose levels, higher urea, creatinine, creatine kinase (CK), CK-MB levels, and slightly increased levels of NT pro-BNP, ECG revealed sinus rhythm with one ventricular premature beat (VPB), 24-h continuous electrocardiogram (ECG) revealed frequent ventricular premature beats (PVB) 2,150/ 24 h, with two couplets, and 8 PAC. After an advised 4-week period of de-training continuous 24 h, ECG monitoring was improved with only occasional PVB. The 24 h continuous ECG monitoring was repeated after HIT and revealed even more frequent PVB, 5% of all beats for 24 h, 4,205 in total, and almost all VPB were in bigeminy and trigeminy. The athlete was advised against RWL and extremely vigorous exercise and for regular, frequent checkups with occasional ECG monitoring during and after exercise. Conclusion The short and long-term implication of abrupt ventricular arrhythmias provoked by intensive training and methods like RWL is unknown. We postulate that cardiovascular screening is necessitated, especially during high-risk methods like RWL and HIT, in helping us prevent adverse outcomes and come to individual-based clinical making decisions for each athlete.
Freshwater mussels (FMs) are useful bioindicators to detect environmental disturbances. However, studies that evaluate FMs suitability for monitoring the hydrodynamic stressors impact are lacking. Since future climatic scenarios predict an increase in frequency and intensity of extreme events, understanding how flood conditions affect freshwater organisms are crucial for their conservation. In this study, we performed experiments in an artificial flume to evaluate the eligibility for FMs behaviour for developing a tailored biological early warning system (BEWS). For this, we used the valvometric technique (Hall magnetic sensors) to measure the FMs valve gaping behaviour when subjected to increasing discharges/sediment transport mimicking the onset of floods. After analysing baseline behaviour in non-stressful conditions, we performed experiments in steady and transient conditions to verify the FMs' response and the threshold that prompted it. Under steady conditions, FMs maintained a constant gaping frequency that characterizes their normal behaviour. The FMs promptly reacted to discharge variations with sediment transport, showing a transition from their normal behaviour to higher valve gaping frequencies. We demonstrated that FM transition behaviour is a useful tool to measure hydrodynamic stressors. A future step will be the application of this BEWS on natural ecosystems to assess possible hydrodynamic changes in real-time.
Background: The cardiovascular risk (CVD) in patients with rheumatoid arthritis (RA) is 1.5-2 times higher than that in individuals of the same age and sex. Aims: To analyse the degree of endothelial dysfunction, the atherogenic immunoinflammatory serum background and the relationships among some vascular indices, cardiovascular comorbidities, and cognitive performance in subjects with RA. Patients and methods: All consecutive patients with a rheumatoid arthritis diagnosis admitted to the Rheumatology Ward of "Policlinico Paolo Giaccone" Hospital of Palermo were enrolled from July 2019 to September 2020. We evaluated our patients' cognitive functions by administering the Mini-Mental State Examination (MMSE). Reactive Hyperaemia Index (RHI) was evaluated for assessment of endothelial function. Serum levels of angiopoietin 2, osteopontin and pentraxin 3 were assessed by blood collection. Results: Fifty-eight consecutive patients with RA and 40 control subjects were analysed. RA patients showed significantly lower mean RHI values, significantly higher mean Augmentation Index (AIX) values and significantly lower mean Mini-Mental State Examination (MMSE) score values than the control group. Patients with rheumatoid arthritis also showed higher mean serum values of pentraxin 3 and angiopoietin 2 than healthy controls. Multivariate logistic regression analysis showed a significant association between pentraxin 3 and angiopoietin 2 and the presence of RA. Discussion: Angiopoietin 2 and pentraxin 3 could be considered surrogate biomarkers of endothelial activation and vascular disease, as they could play an essential role in the regulation of endothelial integrity and inflammation.
Coronary artery anomalies are a heterogeneous group of congenital disorders affecting the coronary pattern with a characteristic (origin, number, number of hosts, course, etc.). They are rarely found in the population. We report the case of a 21-year-old male who died from sudden cardiac death caused by an isolated coronary ostial obstruction, secondary to a rare anomaly, the presence of a valve-like ridge consisting of a small fold in the Valsalva aortic sinus. The study provides a brief literature review on the pathophysiology, diagnosis, and clinical and medico-legal issues in coronary artery anomaly cases that may be helpful in forensic practice when dealing with sudden cardiac death in young people and highlights key points for further research and public health measures.
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7,862 members
Pellegrino Conte
  • Dipartimento di Scienze Agrarie Alimentari e Forestali (SAAF)
Tommaso La Mantia
  • Dipartimento di Scienze Agrarie e Forestali (SAF)
Francesco paolo La mantia
  • Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali
Carmelo Dazzi
  • Dipartimento di Scienze Agrarie e Forestali (SAF)
Information
Address
Piazza Marina 61, 90100, Palermo, Italy
Head of institution
Prof. Fabrizio Micari
Website
www.unipa.it