Composizione lubrificante per processi in colata continua

Diffusasi attorno agli anni 50 del secolo scorso la colata continua a getto aperto (OCP) è il processoindustriale usato per la produzione di travi, tondino, vergella e reti elettrosaldate. Al fine di dissipare gli attrititra strand di acciaio e lingottiera ed evitare il fenomeno di stricking, è necessaria la presenza di un lubrificanteche s’infiltri nello spazio tra lingottiera e acciaio. Tale lubrificante può essere un olio vegetale, come l’olio dicolza oppure oli di origine sintetica come esteri di acidi grassi o polialfaolefine. La scelta su quale olio usaredipende sostanzialmente dal rapporto costi-benefici. L’introduzione negli anni sessanta del ventesimo secolodella tecnologia di colaggio dell’acciaio con tuffante (SEN) e l’opportuna modifica delle proprietà fisiche dellepolveri di colata, fino ad allora utilizzate per il colaggio di lingotti, permise il loro utilizzo nella colata continua[1]. I tentativi di usare la polvere nell’OCP tuttavia ha dato origine a problemi di intrappolamento della stessanell’acciaio con conseguente aumento delle inclusioni non metalliche (NMI). Per questa ragione l’utilizzo diolio rimane predominante in tale processo. Il presente lavoro riporta uno studio sullo sviluppo di un prodotto[2] che renda possibile all’interno del processo di colata continua a getto aperto l’unione dei vantaggi dellapolvere e dell’olio

Blood Pressure Control in Italian Essential Hypertensives Treated by General Practitioners

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Una procedura per la valutazione dei limiti di utilizzo di O-Ring sottoposti ad intensi fasci di neutroni

Si presenta una procedura per la previsione della durata di utilizzo di O-ring in materiale polimerico impiegati nei bersagli per la produzione di fasci di ioni radioattivi. Si sono dapprima condotte prove di tenuta a vuoto e analisi a elementi finiti di un O-ring di riferimento operante con diversi livelli di interferenza con la cava, identificando la precompressione limite per la tenuta e la corrispondente pressione di contatto con la cava. Si sono poi effettuate prove di trazione e di Compression Set su campioni di O-ring in EPDM, preventivamente sottoposti a diversi livelli di irraggiamento in campi misti di neutroni e gamma, analizzando l’effetto della dose assorbita sul comportamento meccanico del materiale e sulle corrispondenti proprietà resistenziali, e definendo opportune leggi costitutive. Si sono infine simulate le progressive modifiche di comportamento della guarnizione indotte dall’irraggiamento, prevedendone la durata in esercizio in termini di tenuta e di resistenza strutturale

Impact of blood glucose variability on carotid artery intima media thickness and distensibility in type 1 diabetes mellitus

Aims. Diabetes mellitus is characterized by structural and functional alterations of the large- and medium-size arteries. Whether blood glucose variability, i.e. the glycemic oscillations occurring during the 24-h period, represents a risk factor for vascular alterations additional to and independent on HbA1c in type 1 diabetes mellitus is still undefined. The present study was carried out with the aim at investigating the impact of different measures of blood glucose variability on arterial structure and function. We studied 17 non-complicated type 1 diabetic patients (11 males, six females) with an age of 40.8 ± 7.6 years (mean ± SD). In each patient, 24-h glucose profile was obtained by continuous glucose monitoring system and glucose variability was expressed as mean ± SD of 24-h blood glucose levels, mean amplitude of glycemic excursions and postprandial hyperglycemic spikes. Arterial structure and function was measured as carotid IMT and stiffness. Major findings. The different approaches to assessing blood glucose variability well correlated between and with HbA1c. Carotid IMT and stiffness showed significant correlations with age, blood pressure, heart rate and daily insulin intake but a non- significant correlation with blood glucose variability. Principal conclusion. Thus, in type 1 diabetes mellitus, measures of glycemic variability are useful in predicting both actual and long-lasting glycemic control. In absence of diabetes-related complications and of any intima-media thickness alterations, the major predictors of arterial distensibility are represented by traditional risk factors beside glycemic 24-h control. © 2013 Scandinavian Foundation for Cardiovascular Researc

Charged particle effects: Experimental and theoretical studies on the mechanisms underlying the induction of molecular and cellular damage and the modulation of intercellular signalling

In this paper we present the main outcomes of a wide collaborative effort (carried out within the INFN project “EPICA” and in part within the European projects “RISC-RAD” and “NOTE” and the ASI project MoMa-COUNT), both experimental and theoretical, devoted to the characterization and quantification of the induction of DNA-targeted and non-DNA-targeted molecular and cellular biological endpoints, following irradiation of human cells with different charged particles. The work was mainly aimed at reaching a better understanding of the mechanisms governing the physical and biophysical pathways leading from the initial energy deposition by radiation in matter to the induction of observable radiobiological damage, with particular focus on the role played by radiation quality. More specifically, we characterized the induction of DNA DSB within different fragment-size ranges outlining the effectiveness of high-LET radiation at inducing small fragments and thus clustered DNA breaks, which can evolve in terms of endpoints like chromosome aberrations (CAs). This was confirmed by the development and application of a model of CA induction based on the assumption that only clustered DNA breaks can lead to aberrations. Concerning non-DNA-targeted damage, we quantified the time-dependent induction of medium-mediated DNA damage in bystander cells and we characterized the time and dose dependence of cytokine concentration in the culture medium of sham-irradiated and irradiated cells, since medium-mediated bystander damage is thought to arise from molecular signalling between irradiated and unirradiated cells. The mechanisms governing such signalling were investigated developing a model and a MC code simulating cytokine release, diffusion and internalization, showing good agreement with experimental data. Non-DNA-targeted effects were further characterized by MRS investigation of the radiation effects on lipids and oxidative metabolism, which are particularly relevant also considering that they may be differently expressed in different tumors and in normal tissues

International comparisons of laboratory values from the 4CE collaborative to predict COVID-19 mortality

Given the growing number of prediction algorithms developed to predict COVID-19 mortality, we evaluated the transportability of a mortality prediction algorithm using a multi-national network of healthcare systems. We predicted COVID-19 mortality using baseline commonly measured laboratory values and standard demographic and clinical covariates across healthcare systems, countries, and continents. Specifically, we trained a Cox regression model with nine measured laboratory test values, standard demographics at admission, and comorbidity burden pre-admission. These models were compared at site, country, and continent level. Of the 39,969 hospitalized patients with COVID-19 (68.6% male), 5717 (14.3%) died. In the Cox model, age, albumin, AST, creatine, CRP, and white blood cell count are most predictive of mortality. The baseline covariates are more predictive of mortality during the early days of COVID-19 hospitalization. Models trained at healthcare systems with larger cohort size largely retain good transportability performance when porting to different sites. The combination of routine laboratory test values at admission along with basic demographic features can predict mortality in patients hospitalized with COVID-19. Importantly, this potentially deployable model differs from prior work by demonstrating not only consistent performance but also reliable transportability across healthcare systems in the US and Europe, highlighting the generalizability of this model and the overall approach

Long-term kidney function recovery and mortality after COVID-19-associated acute kidney injury: An international multi-centre observational cohort study

Background: While acute kidney injury (AKI) is a common complication in COVID-19, data on post-AKI kidney function recovery and the clinical factors associated with poor kidney function recovery is lacking. Methods: A retrospective multi-centre observational cohort study comprising 12,891 hospitalized patients aged 18 years or older with a diagnosis of SARS-CoV-2 infection confirmed by polymerase chain reaction from 1 January 2020 to 10 September 2020, and with at least one serum creatinine value 1–365 days prior to admission. Mortality and serum creatinine values were obtained up to 10 September 2021. Findings: Advanced age (HR 2.77, 95%CI 2.53–3.04, p < 0.0001), severe COVID-19 (HR 2.91, 95%CI 2.03–4.17, p < 0.0001), severe AKI (KDIGO stage 3: HR 4.22, 95%CI 3.55–5.00, p < 0.0001), and ischemic heart disease (HR 1.26, 95%CI 1.14–1.39, p < 0.0001) were associated with worse mortality outcomes. AKI severity (KDIGO stage 3: HR 0.41, 95%CI 0.37–0.46, p < 0.0001) was associated with worse kidney function recovery, whereas remdesivir use (HR 1.34, 95%CI 1.17–1.54, p < 0.0001) was associated with better kidney function recovery. In a subset of patients without chronic kidney disease, advanced age (HR 1.38, 95%CI 1.20–1.58, p < 0.0001), male sex (HR 1.67, 95%CI 1.45–1.93, p < 0.0001), severe AKI (KDIGO stage 3: HR 11.68, 95%CI 9.80–13.91, p < 0.0001), and hypertension (HR 1.22, 95%CI 1.10–1.36, p = 0.0002) were associated with post-AKI kidney function impairment. Furthermore, patients with COVID-19-associated AKI had significant and persistent elevations of baseline serum creatinine 125% or more at 180 days (RR 1.49, 95%CI 1.32–1.67) and 365 days (RR 1.54, 95%CI 1.21–1.96) compared to COVID-19 patients with no AKI. Interpretation: COVID-19-associated AKI was associated with higher mortality, and severe COVID-19-associated AKI was associated with worse long-term post-AKI kidney function recovery. Funding: Authors are supported by various funders, with full details stated in the acknowledgement section

An in-vivo model for hair cell regeneration in frog cristaampullaris.

Hair cells are the primary sensory receptors in both auditory and vestibular organs. In mammals hair cell proliferation and differentiation occur only during embryonic development. In lower vertebrates hair cell production occur at very low levels during adult life, but they retain the ability to regenerate the sensory epithelium after hair cell loss due to different agents such as aminoglycosides. We induced frog crista ampullaris degeneration by intraotic gentamicin administration. Drug induced degeneration starts within 24-48 hrs post treatment and proceeds to be maximal at day 4-5; regeneration is evident at day 6-7 and is almost complete at day 10-11. During degeneration we can first detect the loss of hair cell bundles. Later on we observe two different ways of hair cell degeneration: in some cells we can see vacuolization, nuclear and cytoplasmic swelling followed by enucleation and complete cell degeneration. In other cells morphological data suggest an apoptotic pathway. The degeneration process seems to start in the intermediate zone of the crista ampullaris and then proceeds in the central and lateral regions leaving holes all over the sensory epithelium. These apparent non homogeneous sensitivity to drug induced degeneration seems to correlate with morphofunctional differences of hair cells located in the intermediate, central and lateral compartments of the crista ampullaris. Regeneration starts while degeneration is still occurring and leads to the complete restoration of the sensory epithelium. During the regeneration process we can see supporting cells located nearby the sites of hair cell degeneration, assuming some hair cell-like characteristics as more developed endoplasmic reticulum and Golgi apparatus and immature kinocilia. At the same time, we can see undifferentiated cells spanning the entire epithelium from the basal region to the lumen, with a nuclear morphology similar to those of supporting cells