A Process–Based Rating Curve to model suspended sediment concentration in Alpine environments

A Process-Based Rating Curve (PBRC) approach to simulate mean daily suspended sediment concentration (SSC) as a function of different sediment sources and their activation by erosive rainfall (ER), snowmelt (SM), and icemelt (IM) in an Alpine catchment is presented. Similarly to the traditional rating curve, the PBRC relates SSC to the three main hydroclimatic variables through power functions. We obtained the hydroclimatic variables from daily gridded datasets of precipitation and temperature, implementing a degree-day model to simulate spatially distributed snow accumulation and snow-ice melt. We calibrated the PBRC parameters by an Iterative Input Selection algorithm to capture the characteristic response time lags, and by a gradient-based nonlinear optimization method to minimize the errors between SSC observations and simulations. We apply our approach in the upper Rhône Basin, a large Alpine catchment in Switzerland. Results show that all three hydroclimatic processes ER, SM, and IM are significant predictors of mean daily SSC (explaining 75 %, 12 % and 3 % of the total observed variance). Despite not using discharge in prediction, the PBRC performs better than the traditional rating curve, especially during validation at the daily scale and in reproducing SSC seasonality. The characteristic time lags of the three variables in contributing to SSC reflect the typical flow concentration times of the corresponding hydrological processes in the basin. Erosive rainfall determines the daily variability of SSC, icemelt generates the highest SSC per unit of runoff, and snowmelt-driven fluxes represent the largest contribution to total suspended sediment yield. Finally, we show that the PBRC is able to simulate changes in SSC in the past 40 years in the Rhône Basin connected to air temperature rise, even though these changes are more gradual than those detected in observations. We argue that a sediment source perspective on suspended sediment transport such as the PBRC may be more suitable than traditional discharge-based rating curves to explore climate-driven changes in fine sediment dynamics in Alpine catchments. The PBRC approach can be applied to any Alpine catchment with a pluvio-glacio-nival hydrological regime and adequate hydroclimatic datasets.ISSN:1812-2116ISSN:1812-210

Soft Body Impact Against Aeronautical Structures

Statistics show that impacts of soft body against aeronautical structure are not so rare events. The damage caused by the impact of hailstones or of birds can sometimes be so heavy to compromise the service life of the vehicle. Companies, research centers and universities are interested in the evaluation of the effects of this kind of events and lots of researching works have been recently developed in this field. In this paper, an overview of the last studies performed at the Laboratory for the Safety in Transports (LaST – Crash Lab.) of Politecnico of Milan are presented throughout experimental tests and numerical finite element models. The validity of the correlation results method to prevent possible heavy consequence caused by these events is shown

Adipose-derived mesenchymal stem cells: neuronal differentiation potential and neuroprotective action.

Le cellule mesenchimali staminali adulte derivate dal tessuto adipose (Adipose Stem Cell, ASC) rappresentano, nell\u2019ambito della terapia cellulare, un\u2019alternativa valida agli altri tipi di cellule staminali (Stem Cell, SC) poich\ue8 si possono ottenere in ampia quantit\ue0 dal tessuto adipose, possono esser facilmente coltivate in laboratorio ed espanse. Abbiamo investigato in vitro il potenziale differenziativo delle ASC in senso neuronale usando due tipi di approcci: un trattamento chimico ed un protocollo prolungato in 2 fasi, che include la formazione di sfere e il sequenziale trattamento BDNF (brain-derived neurotrophic factor) e acido retinoico (retinoic acid, RA). Dopo 30 giorni, circa il 57% di ASC mostra caratteristiche morfologiche, fenotipiche ed elettrofisiologiche suggestive di una precoce differenziazione neuronale. Infatti, le ASC assumono una forma allungata, con 2-3 processi citoplasmatici, esprimono selettivamente nestina e le molecule neuronali, fra cui il recettore di GABA-A e tirosina idrossilasi, in assenza di markers gliali. Le cellule differenziate esibiscono un potenziale di membrana negativo ( 1260 mV), correnti di potassio rettificanti ritardate e correnti TTX sensibili, elementi tipici della cellula neuronale; tuttavia non son in grado di generare un potenziale d\u2019azione. Considerando la bassa efficienza del trattamento e la incompleta differenziazione neuronale, abbiamo quindi valutato se le ASC esercitino una funzione neuro-protettiva. Usando il modello di neuroblastoma esposto a H2O2 in vitro, dimostriamo che le ASC aumentano la vitalit\ue0 cellulare (confrontate con i fibroblasti) e proteggono dall\u2019apoptosi. Un possibile meccanismo coinvolto potrebbe esser la secrezione di BDNF, come riportato per le SC mesenchimali (Mesenchymal SC, MSC) derivate da midollo osseo; infatti il medium condizionato di ASC contiene alti livelli di BDNF. Oltre a esibire neuro-protezione, fattori solubili secreti da ASC promuovono la crescita del neurite, un meccanismo aggiuntivo che pu\uf2 favorire la neurorigenerazione. Alla luce di questi dati e dell\u2019azione immunosoppressiva delle ASC recentemente da noi dimostrato (Constantin et al, 2009), le ASC possono essere una utile sorgente di MSC per il trattamento delle malattie neurodegenerative.Adult mesenchymal stem cells derived from adipose tissue (ASC) offer significant practical advantages over other types of stem cells (SC) for potential clinical applications, since they can be obtained from adult adipose tissue in large amounts, can be easily cultured and expanded with a very low risk for development of malignancies. We investigated in vitro the neuronal differentiation potential of human ASC with a chemical protocol and a prolonged two-step protocol, which included sphere formation and sequential culture in brain-derived neurotrophic factor (BDNF) and retinoic acid (RA). After 30 days, about 57% ASC show morphological, immunocytochemical and electrophysiological evidence of initial neuronal differentiation. In fact, ASC display elongated shape with protrusion of two or three cellular processes, selectively express nestin and neuronal molecules (including GABA-A receptor and tyroxine hydroxilase) in the absence of glial phenotypic markers. Differentiated cells show negative membrane potential ( 1260 mV), delayed rectifier potassium currents and TTX-sensitive sodium currents, but they are unable to generate action potential. Considering the low efficacy and the not-fully mature neuronal differentiation, we evaluated if ASC display a neuroprotective effect. Using the H2O2-stressed neuroblastoma model in vitro, we show that ASC increase cell availability (compared to fibroblasts) and protect against apoptosis. A possible mechanism involved could be the secretion of BDNF, as reported for human BM-MSC: in this regard, we indeed find high levels of BDNF in ASCcondition medium. In addition to exert neuroprotection, soluble factors secreted by ASC promote neurite outgrowth, an additional mechanism that may favor neuroregeneration. In view of these results and their immunosuppressive action (Constantin et al, 2009), ASC may be a ready source of adult MSC to treat neurodegenerative diseases

Targeted assessment of the glycolytic enzyme content of extracellular vesicles in the context of exercise

Exercise, capable of greatly increasing intracellular glycolytic rate, has frequently been shown to also induce an increase in circulating exosome-like-vesicles (ELVs) (Frühbeis et al, 2015; Whitham et al, 2018; Brahmer et al, 2019). However, the physiological relevance of ELVs in this context remains elusive. Attempts to unravel the cargo proteome, and therefore potential function, of exercise-mediated ELVs have unexpectedly revealed the expression, and dynamic regulation via exercise, of multiple glycolytic enzymes (Whitham et al, 2018; Vanderboom et al, 2021). Though, some data has contradicted this finding (Jeppesen et al, 2019), and the physiological function of such ELVs enriched with glycolytic enzymes remains unclear. The aim of the present study was therefore to confirm the presence of glycolytic enzymes in ELVs isolated from both murine C2C12 myotube conditioned media and human plasma and test the hypothesis that their expression is modulated by glucose availability and high intensity exercise. Western blots confirmed the presence of multiple glycolytic enzymes alongside classic ELV markers ALIX, TSG101, Syntenin 1 and CD9 in ELV lysates from conditioned media of C2C12 myotubes following both ultracentrifugation (UC) and size exclusion chromatography (SEC) isolation. Furthermore, culturing C2C12 myotubes in high glucose (HG) versus low glucose (LG) media, to assess the role of glucose availability on ELV glycolytic enzyme content, induced a significant (p<0.05) reduction in the expression of GAPDH, PGK1, PMK1, PKM2 and PD in ELVs isolated via UC. Subsequently, in human tetraspanin-positive ELV samples in vivo, we observed the presence of GAPDH at single EV resolution microarray level and dynamic regulation of glycolytic enzymes in response to an exhaustive bout of exercise following immunomagnetic isolation. These data overall demonstrate that glycolytic enzymes are detected in murine muscle cell-derived ELVs in vitro, irrespective of isolation method and are responsive to glucose availability. Furthermore, glycolytic enzymes GAPDH and HKII are present in tetraspanin-positive ELVs in human plasma and are increased in circulation with exercise; supporting the proposition that ELVs transport glycolytic enzymes during the metabolic stress of exercise

Elusione fiscale e abuso del diritto tributario tra legge e diritto vivente. Profili di responsabilità penale.

Per affrontare la questione della rilevanza penale dell’elusione fiscale è indispensabile, innanzitutto, definire l’oggetto del problema. Un obiettivo tanto chiaro quanto difficile da raggiungere, trattandosi di un fenomeno complesso e strettamente legato anche alle scelte del legislatore, il quale, attraverso una regolamentazione sempre più pervasiva, insegue, in una sorta di “gioco del gatto e del topo”, le “invenzioni” della prassi, le quali a loro volta seguono un precedente tentativo legislativo di fermare un altro tentativo di aggiramento, e così via. Dopo aver cercato di definire l’elusione e di individuare i mezzi per contrastarla, esaminando le affermazioni della dottrina e della giurisprudenza tributaristiche italiane e poi le sentenze della CGUE in cui è stato enucleato un principio generale antiabuso valido anche nel diritto tributario, si vedrà come il recepimento di tale principio dalla Cassazione sia alla base della distinzione tra “elusione codificata” e abuso del diritto, utilizzata già in sede amministrativa per escludere dalle sanzioni il secondo, e poi ripresa in ambito penale a partire dal leading case Dolce&Gabbana del 2012. Il “principio D&G” è contestato dalla maggioranza della dottrina e desta perplessità anche la possibilità di sostituire alla tipicità delle fattispecie penali la prevedibilità delle decisioni giurisprudenziali. Intervengono, poi, le riforme del 2015, le quali hanno inciso sia sulla disciplina tributaria dell’elusione - ora equiparata all’abuso del diritto - sia sul sistema penale tributario. A seguito delle modifiche, non pare che il delitto di Dichiarazione fraudolenta mediante altri artifici (art. 3 d.lgs. 74/2000) sia integrabile anche dalle operazioni elusive né che il neo-introdotto art. 10-bis Statuto dei contribuenti possa essere inteso come una convalida legislativa del “principio D&G”. La partita, in ogni caso, rimane aperta e la palla, ancora una volta, è nelle mani della giurisprudenza

FE-to-SPH Approach Applied to the Analysis of Soft Body Impact: Bird Strike and Hail Impact

The soft body impact might be considered as one of the greatest problems for aeronautical structure. To numerically investigate this kind of events both Lagrangian and Smoothed Particles Hydrodynamics (SPH) approaches are generally adopted, but both of them suffer some problems concerning distortion, in Lagrangian elements, and the treatment of essential boundary condition, for SPH approach. The possibility to apply a finite element to SPH transition (FEtoSPH) is here considered. A numerical investigation on hail impact and bird strike phenomenon was performed at the Laboratory for the Safety in Transports (LaST) of Politecnico di Milano. Each of these three approaches was considered for different mesh definitions and impact velocities. A case study concerning the hail impact against an engine inlet was investigated to evaluate the effect of the use of this innovative approach on possible real impact events

Benzylic fluorination induced by N–F bond activation of Selectfluor^® with a solvent-dependent selectivity switch

We present a divergent radical strategy for the fluorination of phenylacetic acid derivatives through N–F bond activation of Selectfluor® with 4-(dimethylamino)pyridine. Comprehensive reaction investigation revealed the critical role of reaction media on selectivity. In presence of water, decarboxylative fluorination through a single electron oxidation is dominant. Non-aqueous conditions result in the clean formation of α-fluoro-α-arylcarboxylic acids through hydrogen atom transfer

Benzylic Fluorination Induced by a Charge-Transfer Complex with a Solvent-Dependent Selectivity Switch

We present a divergent strategy for the fluorination of phenylacetic acid derivatives that is induced by a charge-transfer complex between Selectfluor and 4-(dimethylamino)pyridine. A comprehensive investigation of the conditions revealed a critical role of the solvent on the reaction outcome. In the presence of water, decarboxylative fluorination through a single-electron oxidation is dominant. Non-aqueous conditions result in the clean formation of α-fluoro-α-arylcarboxylic acids