1,653 research outputs found

    Mineralisation of surfactants using ultrasound and the Advanced Fenton Process

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    The destruction of the surfactants, sodium dodecylbenzene sulfonate (DBS) and dodecyl pyridinium chloride (DPC), using an advanced oxidation process is described. The use of zero valent iron (ZVI) and hydrogen peroxide at pH = 2.5 (the advanced Fenton process), with and without, the application of 20 kHz ultrasound leads to extensive mineralisation of both materials as determined by total organic carbon (TOC)measurements. For DBS, merely stirring with ZVI and H2O2 at 20°C leads to a 51% decrease in TOC, but using 20 kHz ultrasound at 40°C, maintaining the pH at 2.5 throughout and adding extra amounts of ZVI and H2O2 during the degradation, then the extent of mineralisation of DBS is substantially increased to 93%. A similar result is seen for DPC where virtually no degradation occurs at 20°C, but if extra amounts of both ZVI and hydrogen peroxide are introduced during the reaction at 40°C and the pH is maintained at 2.5, then an 87% mineralisation of DPC is obtained. The slow latent remediation of both surfactants and the mechanism of degradation are also discussed

    Time series kernel similarities for predicting Paroxysmal Atrial Fibrillation from ECGs

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    We tackle the problem of classifying Electrocardiography (ECG) signals with the aim of predicting the onset of Paroxysmal Atrial Fibrillation (PAF). Atrial fibrillation is the most common type of arrhythmia, but in many cases PAF episodes are asymptomatic. Therefore, in order to help diagnosing PAF, it is important to design procedures for detecting and, more importantly, predicting PAF episodes. We propose a method for predicting PAF events whose first step consists of a feature extraction procedure that represents each ECG as a multi-variate time series. Successively, we design a classification framework based on kernel similarities for multi-variate time series, capable of handling missing data. We consider different approaches to perform classification in the original space of the multi-variate time series and in an embedding space, defined by the kernel similarity measure. We achieve a classification accuracy comparable with state of the art methods, with the additional advantage of detecting the PAF onset up to 15 minutes in advance

    A preclinical model for the ATLL lymphoma subtype with insights into the role of microenvironment in HTLV-1-mediated lymphomagenesis

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    Abstract \uef7f View references (83) Adult T cell Leukemia/Lymphoma (ATLL) is a mature T cell malignancy associated with Human T cell Leukemia Virus type 1 (HTLV-1) infection. Among its four main clinical subtypes, the prognosis of acute and lymphoma variants remains poor. The long latency (3-6 decades) and low incidence (3-5%) of ATLL imply the involvement of viral and host factors in full-blown malignancy. Despite multiple preclinical and clinical studies, the contribution of the stromal microenvironment in ATLL development is not yet completely unraveled. The aims of this study were to investigate the role of the host microenvironment, and specifically fibroblasts, in ATLL pathogenesis and to propose a murine model for the lymphoma subtype. Here we present evidence that the oncogenic capacity of HTLV-1-immortalized C91/PL cells is enhanced when they are xenotransplanted together with human foreskin fibroblasts (HFF) in immunocompromised BALB/c Rag2-/-\u3b3c -/-mice. Moreover, cell lines derived from a developed lymphoma and their subsequent in vivo passages acquired the stable property to induce aggressive T cell lymphomas. In particular, one of these cell lines, C91/III cells, consistently induced aggressive lymphomas also in NOD/SCID/IL2R\u3b3c KO (NSG) mice. To dissect the mechanisms linked to this enhanced tumorigenic ability, we quantified 45 soluble factors released by these cell lines and found that 21 of them, mainly pro-inflammatory cytokines and chemokines, were significantly increased in C91/III cells compared to the parental C91/PL cells. Moreover, many of the increased factors were also released by human fibroblasts and belonged to the known secretory pattern of ATLL cells. C91/PL cells co-cultured with HFF showed features reminiscent of those observed in C91/III cells, including a similar secretory pattern and a more aggressive behavior in vivo. On the whole, our data provide evidence that fibroblasts, one of the major stromal components, might enhance tumorigenesis of HTLV-1-infected and immortalized T cells, thus throwing light on the role of microenvironment contribution in ATLL pathogenesis. We also propose that the lymphoma induced in NSG mice by injection with C91/III cells represents a new murine preclinical ATLL model that could be adopted to test novel therapeutic interventions for the aggressive lymphoma subtype

    Branes and Six Dimensional Supersymmetric Theories

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    We consider configurations of six-branes, five-branes and eight-branes in various superstring backgrounds. These configurations give rise to (0,1)(0,1) supersymmetric theories in six dimensions. The condition for RR charge conservation of a brane configuration translates to the condition that the corresponding field theory is anomaly-free. Sets of infinitely many models with non-trivial RG fixed points at strong coupling are demonstrated. Some of them reproduce and generalise the world-volume theories of SO(32) and E8×E8E_8\times E_8 small instantons. All the models are shown to be connected by smooth transitions. In particular, the small instanton transition for which a tensor multiplet is traded for 29 hypermultiplets is explicitly demonstrated. The particular limit in which these theories can be considered as six-dimensional string theories without gravity are discussed. New fixed points (string theories) associated with EnE_n global symmetries are discovered by taking the strong string coupling limit.Comment: 33 pages, 3 figures, harvmac.tex. References adde

    Generation and interpretation of parsimonious predictive models for load forecasting in smart heating networks

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    Forecasting future heat load in smart district heating networks is a key problem for utility companies that need such predictions for optimizing their operational activities. From the statistical learning viewpoint, this problem is also very interesting because it requires to integrate multiple time series about weather and social factors into a dynamical model, and to generate models able to explain the relationships between weather/social factors and heat load. Typical questions in this context are: “Which variables are more informative for the prediction?” and “Do variables have different influence in different contexts (e.g., time instant or situations)?” We propose a methodology for generating simple and interpretable models for heat load forecasting, then we apply this methodology to a real dataset, and, finally, provide new insight about this application domain. The methodology merges multi-equation multivariate linear regression and forward variable selection. We generate a (sparse) equation for each pair day-of-the-week/hour-of-the-day (for instance, one equation concerns predictions of Monday at 0.00, another predictions of Monday at 1.00, and so on). These equations are simple to explain because they locally approximate the prediction problem in specific times of day/week. Variable selection is a key contribution of this work. It provides a reduction of the prediction error of 2.4% and a decrease of the number of parameters of 49.8% compared to state-of-the-art models. Interestingly, different variables are selected in different equations (i.e., times of the day/week), showing that weather and social factors, and autoregressive variables with different delays, differently influence heat predictions in different times of the day/week

    Ergosterol reduction impairs mitochondrial DNA maintenance in S. cerevisiae

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    Sterols are essential lipids, involved in many biological processes. In Saccharomyces cerevisiae, the enzymes of the ergosterol biosynthetic pathway (Erg proteins) are localized in different cellular compartments. With the aim of studying organelle interactions, we discovered that Erg27p resides mainly in Lipid Droplets (LDs) in respiratory competent cells, while in absence of respiration, is found mostly in the ER. The results presented in this paper demonstrate an interplay between the mitochondrial respiration and ergosterol production: on the one hand, rho° cells show lower ergosterol content when compared with wild type respiratory competent cells, on the other hand, the ergosterol biosynthetic pathway influences the mitochondrial status, since treatment with ketoconazole, which blocks the ergosterol pathway, or the absence of the ERG27 gene, induced rho° production in S. cerevisiae. The loss of mitochondrial DNA in the ∆erg27 strain is fully suppressed by exogenous addition of ergosterol. These data suggest the notion that ergosterol is essential for maintaining the mitochondrial DNA attached to the inner mitochondrial membrane

    Thermodynamics of unfolding of lysozyme in aqueous alcohol solutions.

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    Abstract The thermal denaturation of lysozyme in aqueous alcohol solutions has been investigated through ultraviolet difference spectrophotometry and optical rotation measurements. Alcohols used were CH3OH, C2H5OH, and C3H7OH; concentrations up to 50% (v/v) of alcohol in water were employed. It was found that upon increasing the size or the concentration of the aliphatic alcohol, the denaturation temperature is gradually depressed. At low alcohol concentration, the α helix content of the protein decreases through the thermal transition. However, on increasing alcohol size or concentration, the α helix content goes through a maximum during denaturation. Apparent equilibrium constants and corresponding van't Hoff heats of denaturation were determined. The data indicate that the depression of the denaturation temperature due to addition of alcohols is essentially entropy dependent. It is suggested that these results may be explained in terms of a theoretical expression containing a binding constant for the alcohol to the nonpolar sites of the protein plus a diluent term accounting for changes in the dilution parameters of different conformers

    Razionalizzazione del processo produttivo mediante applicazione di Value Stream Mapping e 5S : il caso Reyvarsur

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    Questa tesi descrive un progetto lavorativo sviluppato in un’azienda spagnola, Reyvarsu S.a.. La tesi sviluppa una dettagliata descrizione dell’ambiente di lavoro, con una successiva adozione di alcune delle tecniche teoriche del modello, dipendentemente dalla situazione riscontrata.La descrizione della tesi inizierà con una breve introduzione della realtà aziendale dove si è svolto il tirocinio, per poi proseguire con la letteratura di Lean Manufacturing, dapprima in generale, e poi nel dettaglio delle tecniche realmente utilizzate. Si descrive infine il progetto vero e proprio ed i risultati ottenuti. Nel primo capitolo verrà descritto in maniera generale la situazione aziendale, della struttura organizzativa e del mercato. Il secondo riguarderà gli argomenti teorici affrontati ed utilizzati nel corso del progetto. Il terzo capitolo descriverà le modalità di implementazione delle 5s, gli obiettivi che si vogliono raggiungere tramite lo sviluppo di tale metodologia e della Value Stream Mapping. Nel quarto capitolo verrà approfondito più dettagliatamente quest’ultimo tema. Il quinto capitolo descrive l’analisi aziendale effettuata, gli strumenti utilizzati e la rappresentazione dello stato attuale dell’impresa. Infine la prima parte del sesto capitolo espone i problemi riscontrati dall’analisi, le azioni svolte di conseguenza e la rappresentazione dello stato futuro. Nella seconda parte viene sviluppato un ipotetico proseguimento della terza fase della Value Stream Mapping, per la continuazione di implementazione del progetto all’interno del caso aziendale
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