255 research outputs found

    The hydro-meteorological chain in Piemonte region, North Western Italy - analysis of the HYDROPTIMET test cases

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    International audienceThe HYDROPTIMET Project, Interreg IIIB EU program, is developed in the framework of the prediction and prevention of natural hazards related to severe hydro-meteorological events and aims to the optimisation of Hydro-Meteorological warning systems by the experimentation of new tools (such as numerical models) to be used operationally for risk assessment. The objects of the research are the mesoscale weather phenomena and the response of watersheds with size ranging from 102 to 103 km2. Non-hydrostatic meteorological models are used to catch such phenomena at a regional level focusing on the Quantitative Precipitation Forecast (QPF). Furthermore hydrological Quantitative Discharge Forecast (QDF) are performed by the simulation of run-off generation and flood propagation in the main rivers of the territory. In this way observed data and QPF are used, in a real-time configuration, for one-way forcing of the hydrological model that works operationally connected to the Piemonte Region Alert System. The main hydro-meteorological events that affected Piemonte Region in the last years are analysed, these are the HYDROPTIMET selected test cases of 14?18 November 2002 and 23?26 November 2002. The results obtained in terms of QPF and QDF offer a basis to evaluate the sensitivity of the whole hydro-meteorological chain to the uncertainties in the numerical simulations. Different configurations of non-hydrostatic meteorological models are also evaluated

    PURINE NUCLEOSIDE PHOSPHORYLASES AS BIOCATALYSTS AND PHARMACOLOGICAL TARGETS

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    A purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) was successfully exploited to catalyze the \u201cone-pot, one-enzyme\u201d regio- and stereoselective transfer of \u3b2-D-ribose from a proper sugar donor (7-methylguanosine iodide) to a library of 6-substituted purine acceptors, resulting in the \u201cin batch\u201d synthesis of 24 ribonucleosides. Transglycosylation conversions confirmed the broad tolerance and the potential of AhPNP as biocatalyst, providing the necessary information to undertake the preparative synthesis of 6-modified purine nucleosides. [1] AhPNP was then immobilized in a stainless steel column resulting in a stable and active bioreactor (AhPNP-IMER, Immobilized Enzyme Reactor) that, upon on-line connection to a semi-preparative HPLC system, was used to run transglycosylations in a flow mode. In such a set-up, biotransformation, on-line monitoring and product purification occurred in a single integrated platform, thus allowing the preparation of five nucleoside analogues at a mg scale (52-89% yield). [2] As a step forward, a \u201cone-pot, two-enzyme\u201d strategy was applied by coupling AhPNP-IMER with an analogous bioreactor based on a uridine phosphorylase from Clostridium perfringens (CpUP), immobilized in a monolith column. The on-line apparatus obtained by connecting CpUP-IMER and AhPNP-IMER in series was tested in the synthesis of adenosine, 2\u2019-deoxyadenosine and arabinosyladenine from uridine, 2\u2019-deoxyuridine and arabinosyluracyl as sugar donors, respectively. The corresponding nucleobases were transformed into the products in 90-95% conversion over 1 h for the ribosyl and 2\u2019-deoxyribosyl derivatives, and 20% conversion after 5 h for arabinosyladenine. [3] Furthermore, a new LC-ESI-MS/MS method was set up to evaluate the inhibition activity of 8-substituted purine ribonucleosides toward the PNP from Mycobacterium tuberculosis (MtPNP), as well as the selectivity against the microbial enzyme with respect to the corresponding human one (HsPNP). The corresponding enzymatic assay, based on the phosphorolysis of inosine, proved to be very convenient in terms of time as well as of target amount. A small library of seven 8-substituted purine ribonucleosides were screened, not exerting any significant effect up to 1 mM, with 8-bromoguanosine and 8-methylaminoguanosine being the only exceptions at 500 mM as weak inhibitors. [4] Finally, the chemical synthesis of a series of 8- and N2-substituted inosinic and guanylic acids as potential ligands of the human GPR17 receptor was carried out, starting from studies aided by molecular modeling on a homology model of the target. The molecules were prepared by 5\u2019-phosphorylation of properly 8- and N2-modified/protected inosine or guanosine. Owing to the scarce nucleophilicity of the exocyclic NH2 group of guanosine, the 2-position of the purine ring was activated as a bromo derivative, whose displacement with the proper amine afforded the desired N2-alkylated products. On the contrary, N2-acylations were carried out through nitrogen functionalization with a proper acyl chloride or anhydride. An additional 2\u2019,3\u2019-O-isopropylidene group was inserted in all the N2-functionalized nucleotides. Binding assays on GPR17 will be carried out. [1] D. Ubiali, C. F. Morelli, M. Rabuffetti, G. Cattaneo, I. Serra, T. Bavaro, A. M. Albertini, G. Speranza Curr. Org. Chem. 2015, 19, 2220-2225; [2] E. Calleri, G. Cattaneo, M. Rabuffetti, I. Serra, T. Bavaro, G. Massolini, G. Speranza, D. Ubiali Adv. Synth. Catal. 2015, 357, 2520-2528; [3] G. Cattaneo, M. Rabuffetti, G. Speranza, T. Kupfer, B. Peters, G. Massolini, D. Ubiali, E. Calleri Submitted 2017; [4] G. Cattaneo, D. Ubiali, E. Calleri, M. Rabuffetti, G. C. Hofner, K. T. Wanner, M. C. De Moraes, L. K. B Martinelli, D. S. Santos, G. Speranza Anal. Chim. Acta 2016, 943, 89-97

    Evaluation of the hydro-meteorological chain in Piemonte Region, north western Italy - analysis of two HYDROPTIMET test cases

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    International audienceThe HYDROPTIMET Project, Interreg IIIB EU program, is developed in the framework of the prediction and prevention of natural hazards related to severe hydro-meteorological events and aims to the optimisation of Hydro-Meteorological warning systems by the experimentation of new tools (such as numerical models) to be used operationally for risk assessment. The object of the research are the Mesoscale weather phenomena and the response of watersheds with size ranging from 102 to 103 km2. Non-hydrostatic meteorological models are used to catch such phenomena at a regional level focusing on the Quantitative Precipitation Forecast (QPF). Furthermore hydrological Quantitative Discharge Forecast (QDF) are performed by the simulation of run-off generation and flood propagation in the main rivers of the interested territory. In this way observed data and QPF are used, in a real-time configuration, for one-way forcing of the hydrological model that works operationally connected to the Piemonte Region Alert System. The main hydro-meteorological events that interested Piemonte Region in the last years are studied, these are the HYDROPTIMET selected test cases of 14-18 November 2002 and 23-26 November 2002. The results obtained in terms of QPF and QDF offer a sound basis to evaluate the sensitivity of the whole hydro-meteorological chain to the uncertainties in the numerical simulations. Different configurations of non-hydrostatic meteorological models are also analysed

    Synthesis of γ-glutamyl derivatives of sulfur-containing amino acids in a multigram scale via a two-step, one-pot procedure

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    \u3b3-Glutamyl derivatives of sulfur amino acids have been prepared in multigram scale starting from readily available starting materials. The synthesis comprises two one-pot operations, both consisting of two reactions. In the first operation, N-phtaloyl-l-glutamic acid anhydride is obtained from l-glutamic acid and phtalic anhydride. In the second one, N-phtaloyl-l-glutamic acid anhydride is used to acylate amino acids and the N-phtaloyl protecting group is removed. The described approach offers a viable entry to \u3b3-glutamyl derivatives of sulfur-containing amino acids with flavor-enhancer and nutraceutical properties

    Operational flood-forecasting in the Piemonte region – development and verification of a fully distributed physically-oriented hydrological model

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    Abstract. A hydrological model for real time flood forecasting to Civil Protection services requires reliability and rapidity. At present, computational capabilities overcome the rapidity needs even when a fully distributed hydrological model is adopted for a large river catchment as the Upper Po river basin closed at Ponte Becca (nearly 40 000 km2). This approach allows simulating the whole domain and obtaining the responses of large as well as of medium and little sized sub-catchments. The FEST-WB hydrological model (Mancini, 1990; Montaldo et al., 2007; Rabuffetti et al., 2008) is implemented. The calibration and verification activities are based on more than 100 flood events, occurred along the main tributaries of the Po river in the period 2000–2003. More than 300 meteorological stations are used to obtain the forcing fields, 10 cross sections with continuous and reliable discharge time series are used for calibration while verification is performed on about 40 monitored cross sections. Furthermore meteorological forecasting models are used to force the hydrological model with Quantitative Precipitation Forecasts (QPFs) for 36 h horizon in "operational setting" experiments. Particular care is devoted to understanding how QPF affects the accuracy of the Quantitative Discharge Forecasts (QDFs) and to assessing the QDF uncertainty impact on the warning system reliability. Results are presented either in terms of QDF and of warning issues highlighting the importance of an "operational based" verification approach

    LOWER LIMB KINETIC VARIABILITY IN VERTICAL JUMPING

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    For more that 50 years vertical jumping exercises have been widely used in sport practice as a measure of power not only to predict athletic ability but also to obtain indications on same near-muscular and motor characteristics of the athletes. The most interesting work in this area has been done by a research group at the Free University of Amsterdam. The studies of these authors evidenced very elegantly that kinetic analysis provides potentially more diagnostic information force derived indices. However, what the majority of previous studies on human extremely large intra subject variability of the joint kinetic variables. So far, no attempts have been made to gain more insight into the variability inherent in moment and power selected measurements in vertical jumping exercises. To the best of our knowledge, in fact, all the studies employed on or more homogeneous subject groups and presented data describing the average performance groups. Furthermore, frequently, when mean values of kinetic parameters for a group were calculated, only the highest jump of each subject was selected for the calculation. The present experiments were devised to gain more insight into the variability of aforementioned biomechanical parameters in order to determine the appropriate number of trails necessary to obtain a stable mean for these parameters and to investigate the interday variability. Eight recreational athletes were the subjects of this study. In two different test sessions, each subject performed 25 double-legged countermovement vertical jumps without the arm swing. Kinematic data, concerning the spatial position often anatomical landmarks (five per each leg), were recorded by means of an optoelectronic system (ELITE) with a sampling rate of 100 Hz. Simultaneously, ground reaction forces were measured with a Kistler force platform at the sampling rate of 1000 Hz. The internal joint centres, such as the corresponding moments and powers, were estimated by using a special software (SAFLO) which inputs were anthropometric, kinematic and kinetic data. Preliminary results show that, considering all the subjects, power mean value stability ranges from 11 to 16 trials. Interday correlation was higher for hip and ankle and lower for knee values. These results suggest the need to adopt multiple trial protocols to reach reliable results suitable for identifying meaningful performance differences

    Effects of temperature on flood forecasting: analysis of an operative case study in Alpine basins

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    Abstract. In recent years the interest in the forecast and prevention of natural hazards related to hydro-meteorological events has increased the challenge for numerical weather modelling, in particular for limited area models, to improve the quantitative precipitation forecasts (QPF) for hydrological purposes. After the encouraging results obtained in the MAP D-PHASE Project, we decided to devote further analyses to show recent improvements in the operational use of hydro-meteorological chains, and above all to better investigate the key role played by temperature during snowy precipitation. In this study we present a reanalysis simulation of one meteorological event, which occurred in November 2008 in the Piedmont Region. The attention is focused on the key role of air temperature, which is a crucial feature in determining the partitioning of precipitation in solid and liquid phase, influencing the quantitative discharge forecast (QDF) into the Alpine region. This is linked to the basin ipsographic curve and therefore by the total contributing area related to the snow line of the event. In order to assess hydrological predictions affected by meteorological forcing, a sensitivity analysis of the model output was carried out to evaluate different simulation scenarios, considering the forecast effects which can radically modify the discharge forecast. Results show how in real-time systems hydrological forecasters have to consider also the temperature uncertainty in forecasts in order to better understand the snow dynamics and its effect on runoff during a meteorological warning with a crucial snow line over the basin. The hydrological ensemble forecasts are based on the 16 members of the meteorological ensemble system COSMO-LEPS (developed by ARPA-SIMC) based on the non-hydrostatic model COSMO, while the hydrological model used to generate the runoff simulations is the rainfall–runoff distributed FEST-WB model, developed at Politecnico di Milano
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