1,721,168 research outputs found
Reflections on the unexpected laboratory finding of hemorheological alterations observed in some haematological disorders
Full text linkHyperviscosity syndrome is a clinical condition characterized by the slowing of blood flow through the vessels and it may be associated with several diseases. The nosographic classification of primary hyperviscosity conditions (Wells classification 1970) divided the primary hyperviscosity syndromes in polycythaemic, sclerocytemic and sieric. Recent and personal laboratory observations have highlighted an unexpected behaviour of the erythrocyte deformability observed in some haematological disorders such as polycythemia vera, multiple myeloma and monoclonal gammopathy of undetermined significance. The interest of this observation depends on the fact that up to now, according to the Wells classification, the hemorheological alteration present in PV was related to the increase of RBC mass while that present in MM and MGUS was attributable to the abnormality of plasma or serum viscosity only. Through an extensive research among the literature, using MEDLINE/PubMed to identify all published reports on the hyperviscosity syndromes, issues that until now have been dealt with separately will therefore be analyzed in a unique paper, allowing a global view. The aim of this paper is to provide some suggestions for reflection and emphasizing the need of a nosographic framework of hyperviscosity that, probably, deserves to be reviewed
Estimation of distribution parameters as a tool for model-based system engineering and model identification
Full text linkThe estimation of the parameters of a probability distribution (e.g., moments) plays an important role both in the model-based system engineering (e.g., analysis and verification through Statistical Model Checking (SMC)) and in the identification of parameters of predictive models (e.g., systems biology, social networks). The contribution of this PhD thesis is both on the algorithm side and on the modeling side. On the algorithm side, we overview a set of Monte Carlo-based Statistical Model Checking tools and algorithms for the verification of Cyber-Physical Systems, and we provide selection criteria for the verification problem at hand. Furthermore, we present an efficient Monte Carlo-based algorithm to estimate the expected value of a multivariate random variable, when marginal density functions are not known. We prove the correctness of our algorithm, we give an Upper Bound and a Lower Bound to its complexity and we present experimental results confirming our evaluations. On the modeling side, we present a mechanistic and identifiable model to predict, at the node level and at a set of nodes level, the expected value of the retweeting rate of a message inside a social network, at a certain time. Our model parameters are random variables, whose distribution parameters are estimated from an available dataset. We experimentally show that our model reliably predicts both the qualitative and the quantitative time behavior of retweeting rates. This is confirmed by the high correlation between the predicted and the observed data. These results enable a simulation-based analysis of users or of a set of users' behaviors inside a network
Realizzazione e prova di celle complete da laboratorio. Definizione del design di cella
Full text linkIl presente rapporto illustra il design di cella sviluppato per la realizzazione (in scala di laboratorio) di celle complete litio-ione per applicazioni alle reti elettriche. Nel corso delle attività svolte nel periodo ottobre 2011 – settembre 2012 sono stati utilizzati due differenti design di cella. Il primo, denominato “tipo T”, è stato sviluppato nel precedente periodo di attività (ottobre 2010 - settembre 2011) ed è stato impiegato per la caratterizzazione elettrochimica dei materiali catodici e anodici (in elettrolita organico convenzionale) sviluppati e selezionati (nel periodo di attività ottobre 2011 - settembre 2012) nel corso delle attività relative agli Obiettivi A e B.
Il secondo design di cella è stato appositamente sviluppato per celle complete litio-ione che utilizzano un elettrolita poco volatile ed ininfiammabile (data la presenza di liquidi ionici). Quest’ultima tipologia ha permesso la realizzazione di celle sottili aventi spessore totale attorno 200 micrometri (inclusi i portacorrente elettrodici). Le celle sono alloggiate in contenitori “soffici” (denominati coffee-bag), impermeabili ad acqua ed aria e aventi bassa densità e, successivamente, sigillate sotto vuoto. La presente tipologia presenta numerosi vantaggi: i) elevata sicurezza (ininfiammabilità) della cella; ii) assenza di ossigeno (entro la cella) che, come noto, promuove fenomeni di riduzione dell’elettrolita; iii) nessuna possibilità di contaminazione con l’esterno; iv) adattabilità a diverse geometrie di cella; v) robustezza e flessibilità meccanica della cella; vi) aumento energia specifica della batteria dovuto alla diminuzione in peso del contenitore. I risultati ottenuti sono riferiti al periodo di attività ottobre 2011–settembre 2012
Evaluation Software for Fuel Cells Performance Tests
No full textA software to evaluate the performances of fuel cells. has been developed The software, initially developed for Molten. Carbonate Fuel Cells, allows to realize some measurement tests. on it, satisfying flexibility characteristics particularly appreciated. by qualified developer and researcher. The software allows to. verify both single cells and whole stack by the control of voltage. waveform versus time or current. Moreover it can be used also. for other kind of fuel cells
Distribuzione, ecologia e status conservativo di Petagnaea gussonei (Sprengel) Rauschert (Apiaceae).
No full textThe function of matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor (TIMP-1) in several clinical conditions: Results and analysis of our survey
No full textThe goal of this research was to evaluate the plasma concentration of MMP-9 and its tissue inhibitor (TIMP-1) in different clinical conditions. It included several groups of subjects: 31 overweight subjects; 91 obese adults divided into two subgroups according to the BMI value (BMI 30-35Kg/m2 and BMI>35Kg/m2); 90 subjects with metabolic syndrome (MS) divided into two subgroups (with and without diabetes mellitus); 100 subjects with preclinical carotid atherosclerosis (PCA) divided according to the number of cardiovascular risk factors and to the insulin resistance degree; 48 subjects with obstructive sleep apnoea syndrome (OSAS) divided according to the apnoea/hypopnea index (AHI); 27 subjects with chronic kidney disease (CKD) on conservative management; 31 subjects with CKD on regular haemodialysis treatment. We have found a significant increase of MMP-9 and TIMP-1 in overweight subjects, in obese adult and in MS subjects. In obese adults, the behaviour of these two parameters was not influenced by the degree of obesity, while in the group of MS subjects both these parameters were clearly influenced by the presence of diabetes mellitus. In subjects with PCA, we observed an increase of MMP-9 associated with a significant decrease of TIMP-1; the same trend was found by subdividing the entire group in accordance with the number of cardiovascular risk factors and with the insulin resistance degree. In subjects with OSAS, we noted an increase in MMP-9 and TIMP-1; this increase was more evident in subjects with OSAS having AHI>30. In individuals with CKD on conservative and haemodialysis treatment we have found, at baseline, a marked increase in MMP-9 and a significant decrease of TIMP-1. In dialyzed subjects, after a standard dialysis session was noted, a significant increase in MMP-9 was associated with a further decrease in TIMP-1
Evaluation of oxidative stress in coronary heart disease at baseline and during exercise test
No full textOxidative stress has probably a role in coronary heart disease (CHD), but studies
focused on the behaviour of oxidative status in patients with stable CHD have
obtained controversial results. On the other hand, an increased release of
leukocyte elastase is considered a marker of CHD. Exercise can induce oxidative
stress and leukocyte activation, so the aim of this study was to evaluate
oxidative status and plasma elastase level in a group of subjects with stable
coronary heart disease (CHD), at baseline and during an exercise test. We
enrolled 15 patients with previous acute myocardial infarction, all treated with
statins and platelet antiaggregating agents. As parameters of oxidative status we
determined the thiobarbituric acid reactive substances and total antioxidant
status (TAS). The exercise test was performed according to the Bruce protocol. At
baseline, elastase level was higher in CHD subjects than in normal controls and
during the exercise test it increased in both groups in comparison with basal
values. Regarding oxidative status, only TAS was slightly lower in CHD subjects
than in normal controls. In both groups, during exercise test, no parameter of
oxidative status was significantly different compared to basal values. In
conclusion, CHD patients showed, at rest, an abnormal neutrophil activation and a
lower antioxidant status. The exercise test further activated neutrophils but did
not influence oxidative status. The absence of a marked oxidative stress in our
patients may be partly due to the pharmacological treatment, which apparently did
not influence the abnormal leukocyte activation
Haemorheological profile in congenital afibrinogenemia and in congenital dysfibrinogenemia: A clinical case report
No full textAlthough the inherited quantitative and qualitative disorders of fibrinogen are rare, in the course of time patients may develop complications including episodes of arterial and venous thrombosis. It can be useful to complete the laboratory assessment of these clinical conditions with the evaluation of the haemorheological profile. The data obtained from this study showed that congenital afibrinogenemia was characterized by a primary plasma hypoviscosity, whereas congenital dysfibrinogenemia by a primary plasma hyperviscosity. Both these haemorheological alterations may concur, with different mechanisms, to the pathogenesis of thrombotic vascular complications
Realizzazione e prova di celle complete da laboratorio. Caratterizzazione chimico-fisica di miscele elettrolitiche miste
Full text linkIl presente rapporto descrive la caratterizzazione chimico-fisica di miscele elettrolitiche miste da utilizzare in celle complete litio-ione per applicazioni alle reti elettriche nell’ambito dell’Accordo di Programma ENEA-MSE. Le suddette miscele sono costituite da un sale di litio (LiTFSI), solventi organici convenzionali (EC e DEC) ed un liquido ionico (PYR13TFSI). La presenza del liquido ionico (sintetizzato seguendo una procedura sviluppata in ENEA e selezionato per le sue proprietà chimico-fisiche) ha lo scopo di diminuire fortemente la volatilità e l’infiammabilità della soluzione elettrolitica evitando, però, di deprimerne la conduzione ionica e la stabilità elettrochimica. L’obiettivo è quello di realizzare celle litio-ione ad elevata energia e dotate, al contempo, di elevata sicurezza.
Gli elettroliti misti sono stati investigati in termini di analisi termica, conducibilità ionica, viscosità e densità in funzione sia della temperatura che della composizione molare all’interno di una camera secca ad atmosfera controllata avente un tenore di umidità inferiore a 10 ppm. Inoltre test di infiammabilità sono stati eseguiti al fine di ottenere informazioni, sia pur qualitative, sul comportamento degli elettroliti all’ignizione.
Sono state inizialmente caratterizzate miscele binarie (x)LiTFSI-(1-x)PYR13TFSI), ove x e (1-x) rappresentano la frazione in moli del sale di litio e del liquido ionico, rispettivamente. La frazione ottimale di LiTFSI è risultata essere pari a 0.1.
Successivamente, sono state investigate miscele quaternarie aventi composizione molare (0.1)LiTFSI- (0.9-x)PYR13TFSI-(x)EC/DEC. Il rapporto molare LiTFSI / (PYR13TFSI + EC/DEC) è stato fissato pari a 0.1/0.9 mentre il rapporto in peso EC:DEC è pari a 1:1. La frazione ottimale di EC/DEC è risultata essere pari a 0.3 che garantisce una conducibilità nettamente più elevata rispetto la miscela (0.1)LiTFSI - (0.9)PYR13TFSI) ma, al contempo, non rende infiammabile l’elettrolita risultante.
Infine, miscele elettrolitiche aventi composizione molare (x)LiTFSI-(y)PYR13TFSI-(1-x-y)EC/DEC (ove il rapporto molare y/(1-x-y) è stato fissato pari a 0.6/0.3) sono state investigate al fine di definire il contenuto ottimale di sale di litio. Tuttavia la frazione ottimale di LiTFSI è risultata essere ancora pari a 0.1. Pertanto, la soluzione elettrolitica mista selezionata per le celle complete litio-ione è risultata essere (0.1)LiTFSI-(0.6)PYR13TFSI-(0.3)EC/DEC. I risultati ottenuti sono riferiti al periodo di attività ottobre 2011–settembre 2012
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