Studio della fluidita dl leghe a base rame

Le leghe di rame sono spesso utilizzate nella produzione di getti o semilavorati con svariate composizioni per la versatilit\ue0 del processo di colata, che permette di utilizzare diverse tecniche e svariati materiali al fine di ottenere le caratteristiche desiderate. Tuttavia, nonostante questa tecnologia di produzione sia largamente utilizzata, non esiste ad oggi un test normato atto a determinarne i parametri ottimali e a prevenire eventuali difetti. Questo lavoro nasce dall'esigenza di mettere a punto un sistema di misura affidabile, che possa ambire a diventare uno standard di uso comune per la valutazione di un parametro fondamentale, come la col abilit\ue0, e che contribuisca allo studio dell\u2019influenza sia di fattori produttivi che di fattori chimici, come la presenza di elementi in lega in concentrazioni macro o micro (< 1%). La ricerca si focalizza sulla standardizzazione di un test di fluidit\ue0 che risponda alle esigenze scientifiche di precisione, sensibilit\ue0 e riproducibilit\ue0, mantenendo l\u2019aspetto pratico di semplicit\ue0 di realizzazione poich\ue9 possa essere di interesse per prove di fonderia

Quantitative assessment of HCC wash-out on CT is a predictor of early complete response to TACE

OBJECTIVES: To investigate the predictive value of four-phase contrast-enhanced CT (CECT) for early complete response (CR) to drug-eluting-bead transarterial chemoembolization (DEB-TACE), with a particular focus on the quantitatively assessed wash-in and wash-out. METHODS: A retrospective analysis of preprocedural CECTs was performed for 129 HCC nodules consecutively subjected to DEB-TACE as first-line therapy. Lesion size, location, and margins were recorded. For the quantitative analysis, the following parameters were computed: contrast enhancement ratio (CER) and lesion-to-liver contrast ratio (LLC) as estimates of wash-in; absolute and relative wash-out (WO(abs) and WO(rel)) and delayed percentage attenuation ratio (DPAR) as estimates of wash-out. The early radiological response of each lesion was assessed by the mRECIST criteria and dichotomized in CR versus others (partial response, stable disease, and progressive disease). RESULTS: All quantitatively assessed wash-out variables had significantly higher rates for CR lesions (WO(abs) p = 0.01, WO(rel) p = 0.01, and DPAR p = 0.00002). However, only DPAR demonstrated an acceptable discriminating ability, quantified by AUC = 0.80 (95% CI0.73–0.88). In particular, nodules with DPAR ≥ 120 showed an odds ratio of 3.3(1.5–7.2) for CR (p = 0.0026). When accompanied by smooth lesion margins, DPAR ≥ 120 lesions showed a 78% CR rate at first follow-up imaging. No significative association with CR was found for quantitative wash-in estimates (CER and LLC). CONCLUSIONS: Based on preprocedural CECT, the quantitative assessment of HCC wash-out is useful in predicting early CR after DEB-TACE. Among the different formulas for wash-out quantification, DPAR has the best discriminating ability. When associated, DPAR ≥ 120 and smooth lesion margins are related to relatively high CR rates. KEY POINTS: • A high wash-out rate, quantitatively assessed during preprocedural four-phase contrast-enhanced CT (CECT), is a favorable predictor for early radiological complete response of HCC to drug-eluting-bead chemoembolization (DEB-TACE). • The arterial phase of CECT shows great dispersion of attenuation values among different lesions, even when a standardized protocol is used, limiting its usefulness for quantitative analyses. • Among the different formulas used to quantify the wash-out rate (absolute wash-out, relative wash-out, and delayed percentage attenuation ratio), the latter (DPAR), based only on the delayed phase, is the most predictive (AUC = 0.80), showing a significant association with complete response for values above 120

Liver involvement in patients with COVID-19 infection: A comprehensive overview of diagnostic imaging features

During the first wave of the pandemic, coronavirus disease 2019 (COVID-19) infection has been considered mainly as a pulmonary infection. However, different clinical and radiological manifestations were observed over time, including involvement of abdominal organs. Nowadays, the liver is considered one of the main affected abdominal organs. Hepatic involvement may be caused by either a direct damage by the virus or an indirect damage related to COVID-19 induced thrombosis or to the use of different drugs. After clinical assessment, radiology plays a key role in the evaluation of liver involvement. Ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) may be used to evaluate liver involvement. US is widely available and it is considered the first-line technique to assess liver involvement in COVID-19 infection, in particular liver steatosis and portal-vein thrombosis. CT and MRI are used as second- and third-line techniques, respectively, considering their higher sensitivity and specificity compared to US for assessment of both parenchyma and vascularization. This review aims to the spectrum of COVID-19 liver involvement and the most common imaging features of COVID-19 liver damage

Imaging of long head biceps tendon : a multimodality pictorial essay

The aim of this article is to provide an imaging review of normal anatomy, most common anatomical variants and pathologies of the long head of the biceps tendon (LHB) encountered during the daily practice. (www.actabiomedica.it)

Estudio de la relación y el sexo de la Haematobia irritans (Diptera: Muscidae) y la susceptibilidad/resistencia a la cipermetrina

La Haematobia irritans, mosca de los cuernos es un díptero hematófago, parásito obligado de los bovinos, que provoca importantes pérdidas ecónomicas en la producción de leche y carne. Está ampliamente distribuida en nuestro país y para combatirla se han utilizado en forma masiva piretroides sintéticos, lo cual produjo poblaciones de moscas resistentes a este principio activo de bajo costo y alta toxicidad para el parásito. Uno de los mecanismos de la resistencia a los piretroides es la mutación en el gen del canal de sodio reemplazando una leucina por fenilalanina, otorgándole resistencia del tipo kdr (knockdown resistance). Esta mutación puede detectarse, en forma individual, mediante la reacción en cadena de la polimerasa (PCR). El objetivo del presente ensayo fue evaluar la relación de la proporción entre individuos adultos machos y hembras con ausencia o presencia de la mutación kdr. Para estimar la cantidad de especímenes homocigotos y heterocigotos según el sexo, se capturaron moscas de bovinos de la EEA INTA Rafaela desde febrero a diciembre de 2003. Para determinar la dosis letal 50 ( DL50 ) se utilizaron papeles de filtro impregnados con diferentes concentraciones de cipermetrina. Según la DL 50 se estratificó en: DL50 menor 4 μg/cm2; entre 4.1 y 6 μg/cm2 y mayor de 6 μg/cm2. De cada una de las muestras obtenidas de esta población de campo, se tomaron al azar moscas y se determinó el sexo de las mismas y mediante la técnica de PCR se constató la presencia o ausencia de la mutación genética. Para cada uno de los estratos se comparó la proporción de machos homocigotos susceptibles (ss) vs hembras homocigotas susceptibles (ss), machos heterocigotas (sr) vs hembras heterocigotas (sr) y machos resistentes homocigotas (rr) vs hembras resistentes homocigotas (rr). La comparación de proporciones según sexo y DL 50 se analizó mediante Chi - cuadrado. En las condiciones de este ensayo no hubo diferencias significativas, en los diferentes rangos de DL50, en la proporción de hembras y machos ya sea homocigotas o heterocigotas.Fil: Castelli, M. E.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Carlos Pellegrini.; ArgentinaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Carlos Pellegrini.; ArgentinaFil: Bertello, C.. Sin filiación; ArgentinaFil: Faletti, C. M.. Universidad Nacional de Rosario; ArgentinaFil: Guglielmone, Alberto Alejandro. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Santa Fe. Estacion Experimental Agropecuaria Rafaela. Agencia de Extension Rural Carlos Pellegrini.; Argentin