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Gaseous fuel utilisation reduces pollutant emissions and makes energy systems less dependent from oil. Their carbon content is low, which means a reduction in CO2 emissions per unit of energy in comparison with liquid fossil fuels. The use of biogases (BG) and/or natural gas (NG) in internal combustion engines (ICE) is very attractive. To increase the efficiency of NG engines hydrogen can be added to natural gas, and innovative BG containing hydrogen can be conveniently used. Hydrogen has a high combustion speed, providing a reduction of the combustion duration when mixed with methane. Consequently higher temperatures are attained in the combustion chamber and thus engines fuelled with NG/H2 blends increase the NOx emissions. NG and BG are generally adopted as fuel in positive ignition ICEs; however they are also suitable for fuelling Controlled Auto Ignition (CAI) engines. The authors investigated combustion in CAI ICE by means of numerical simulations. Starting with pure CH4, the fuel was subsequently enriched with H2, comparing engine performance and exhaust emissions. CAI systems are indirectly controlled with varying air-fuel ratio, boost pressure and charge temperature. Charge temperature depends on the residual gas content, which has an impact on the combustion process as the burning mixture composition consequently changes. The authors investigated the effect of exhaust gas recirculation on the in-cylinder gas temperature and reaction mechanism, with main focus on NOx emissions. Hydrogen addition reduces the intake temperature requirement for the autoignition, which means less EGR. Hydrogen enriched fuels also require lower boost pressure than CH4 to deliver the reference imep while engine efficiency does not change significantly between tested fuels. Hydrogen also helps in reducing NOx emissions due to lower boost pressure and EGR rates.

In polymer processing as fibre spinning, injection moulding, film casting and so on, the forming phase of the melt is followed by its solidification due to cooling. This implies the crystallization of the polymer during the processing. Typically, crystallites are formed and an ordered structure can be detected, if the cooling rate is not too high. As a consequence, during processing the rheological response of the material significantly changes from a liquid-like to a solid-like behaviour. The knowledge of the mechanical response of the material during crystallization is therefore of seminal importance for process control and modelling. We here focus on a random copolymer, the Ethylene vinyl acetate (EVA), made of ethylene and varying amounts of vinyl acetate that interfere with poly-ethylene chain packing reducing the crystallinity, improving the transparency and lowering the melting temperature. This allows studying the crystallization kinetics at relatively low temperatures so to avoid all the experimental issues related to thermal degradation. The crystallization process is rheologically studied in non-isothermal conditions and the frequency spectra are measured at different temperatures to investigate the viscoelasticity of EVA during the change of phase. Coupling the crystallization kinetics and the viscoelastic spectra at different temperatures, i.e. at different degree of crystallinity, we determine two independent shift factors, one for the time-crystallinity shift, the other for the time-temperature shift, so to propose a new time-temperature-crystallinity superposition to reconcile all the data on a single master curve. In this way, the experimentally observable frequency range has been widen significantly so to detect all the relaxation times of the material from the shortest to the largest ones.

La presente invenzione riguarda il campo dei profarmaci, utili nel trattamento delle disfunzioni endoteliali e di ogni altra patologia causata da una ridotta disponibilità di arginina e/o di monossido d’azoto. L’Arginina è considerata l’unico precursore fisiologico per la formazione di NO. Essa è classificata come aminoacido semi-essenziale essendo parzialmente assorbita dalla dieta e parzialmente sintetizzata de novo nell’adulto sano (Nutr. Rev. 1976, 34, 307-9; J. parent. Ent. Nutr. 1986, 10, 227-238). Si descrivono esteri dell’arginina (enantiomeri L- e/o D-) con D-galattosio utili come profarmaci dotati di elevata capacità di penetrazione attraverso le membrane cellulari e la barriera ematoencefalica. Gli esteri dell’invenzione, una volta assorbiti, rilasciano gradualmente l’arginina ed assicurano livelli di farmaco prolungati e elevati, generando una risposta terapeutica consistente e prolungata nel tempo. Ulteriori descrizioni Senza limitazione alcuna, ogni malattia che trae beneficio dal trattamento con arginina, è vantaggiosamente trattabile anche con i presenti esteri, i quali permettono una maggiore accessibilità dell’aminoacido nei comparti dell’organismo posti oltre le membrane cellulari e/o la BEE. Gli esteri dell’invenzione sono in grado di attraversare le membrane cellulari e la BEE sfruttando i sistemi di trasporto transmembranali specifici per gli aminoacidi cationici (Y+, B0,+, b0,+ e Y+L). Da un punto di vista tecnico, le metodologie utilizzate per l’ottenimento di questi risultati comprendono sintesi organica, NMR, HPLC-massa, colture cellulari, microscopia convenzionale e confocale. L’esterificazione con galattosio ha permesso l’ottenimento di una maggiore concentrazione di arginina a livello intracellulare e del SNC, facilitandone il passaggio attraverso le membrane plasmatiche e la BEE. Le malattie trattabili con gli esteri della presente invenzione sono in particolare le seguenti. Disfunzioni endoteliali, intendendo con tale termine ogni patologia caratterizzata da una alterata funzionalità dell’endotelio. Esempi di tali disfunzioni sono: insufficienza cardiaca congestizia, aterosclerosi, sindromi coronariche acute, angina pectoris, scompenso cardiaco cronico, ipertensione arteriosa (essenziale, reno-vascolare, gravidica o preclampsia, portale, ecc.). Altre malattie che possono vantaggiosamente essere trattate con gli esteri dell’invenzione sono: diabete, iperammoniemia da insufficienza epatica, disfunzioni erettili, dispermie seminali, in particolare quelle in presenza di oligoastenospermia, oligozoospermia e bradicinesi, patologie collegate ad una ridotta disponibilità di ormone della crescita (ad es. deficit della crescita), patologie collegate ad una ridotta disponibilità di poliamine cerebrali, patologie neurodegenerative quali il Morbo di Alzheimer, il morbo di Parkinson e l’ictus cerebrale, ecc. Grazie all’attività elevata e prolungata nel tempo dei presenti esteri, si è ottenuto il vantaggio di evitare somministrazioni di arginina in dosaggi particolarmente elevati, e/o ripetute a breve frequenza nel tempo, con particolare vantaggio per quei trattamenti di carattere curativo o preventivo che richiedono una terapia prolungata. Inoltre, il superamento della BEE ha permesso di sfruttare efficacemente le azioni dell’arginina per patologie a carico del sistema nervoso centrale e periferico, evitando complicate e fastidiose procedure di somministrazione in-situ. Ulteriore oggetto dell’invenzione sono composizioni farmaceutiche, utili per il trattamento di patologie che beneficiano del trattamento con arginina, caratterizzate dal contenere un estere di arginina e D-galattosio.

A soil depleted of its organic carbon content is typically destabilized, i.e., its capacity to maintain its microstructure intact under various stress conditions weakens, and consequently, landslides and mudflows can be triggered and propagated more easily. In a previous work, we showed with a rheological analysis that the removal of the sole water-soluble organic carbon “destabilized” the slurry very similarly to what occurs with the removal of the vast majority of soil organic carbon. In principle, the water-soluble organic carbon can be dissolved by rainfall, during which water can infiltrate the soil, eventually leaving it either by percolation or evaporation. These two processes are mimicked here with two different soil water wetting procedures. The stability of the treated (wetted) soils is studied with rheological and granulometric experiments. The former run on concentrated suspensions, while the latter run on very diluted ones. Despite this, the results agreed very well, indicating that the two wetting procedures induce the same destabilization of the soil which behaves as the one depleted by the whole water-soluble organic carbon. Our results concluded that a soil destabilized by a wetting procedure, i.e., by a rainfall event, will be more prone to trigger a landslide that will propagate more swiftly and will stop with more difficulties.

Introduction: Pain and spasms of urinary and biliary tracts are conditions causing poor quality of life. Treatment with analgesic drugs such as non-steroidal anti-inflammatory drugs and modulators of the parasympathetic system are not always tolerated, and often additional therapeutic options are necessary. The present analysis aimed to evaluate the pharmacokinetics and effectiveness of oral and parenteral preparations based on phloroglucinol in reducing pain and spasms associated with renal or biliary colic in phase 3, multicentre, open-label, randomized, comparative studies on clinical effectiveness and safety. Methods: Pharmacokinetic and pharmacodynamic studies were carried out. Four phase 3 multicentre, open-label, randomized, comparative studies were conducted to evaluate the clinical effectiveness and safety in patients with pain and spasms of urinary or biliary tracts. Eligible patients randomly received either phloroglucinol orally or via intramuscular (IM)/intravenous (IV) administration and reference drug, dexketoprofen for urinary spasms and pain, the non-steroidal anti-inflammatory drug metamizole or scopolamine-based reference drug for biliary colic. The primary outcomes were symptoms and observed frequency of spasms, while the secondary outcome was the duration of improvement or the time between the drug administration and the recurrence of symptoms. Comparison of groups by quantitative characteristics was performed using the T-test for independent samples or the Mann-Whitney test. Intragroup comparisons were performed using the Wilcoxon test, or the T-test for linked samples. Qualitative signs were analysed using the Pearson's χ2 test and Fisher's exact test. Results: The pharmacokinetic studies showed that (i) most of the phloroglucinol (> 80% for IV and per os formulations) was eliminated in the first 6 h after dosing, (ii) the drug was eliminated in urine as unchanged phloroglucinol (1,3,5-trihydroxybenzene) in a small proportion (

It is important from both a strategic and economic standpoint to study the mechanism of formation of water/oil emulsions, to predict their increase of viscosity with respect to that of the crude oil, and to obtain information about the stability vs separation of these substances (since their presence can impair oil processing and distribution). The objective of this work was to ascertain the influence of monoethylene glycol (MEG) on these parameters and its action mechanism. The addition of MEG in different proportions in the oil emulsions significantly changed the flow curve of the emulsion, passing from a quasi-Newtonian one to a shear thinning behaviour. Besides this, when MEG was present at low concentrations, the demulsification process was slow and an increase in concentration made the emulsions more stable than samples containing the same aqueous phase proportion. Under the conditions studied, the addition of MEG did not reduce the quantity of the aqueous phase separated compared to the emulsions free of MEG, but significantly delayed the demulsification process. Rheology provided important information regarding the phase separation process of the aqueous phase in oil phase emulsions, and dynamic testing suggested that the most relevant effect of the addition of MEG is an increase of the emulsion elasticity that can be correlated with the increase in the emulsion stability observed by bottle test and Turbiscan.

The Na+/Ca2+ exchanger (NCX) plays a fundamental role in controlling intracellular levels of Na+ and Ca2+ in neuronal cells.1 Because under anoxic/ischemic conditions the intracellular homeostasis of these cations is altered, the role played by NCX in conditions of cellular anoxia or in vivo cerebral ischemia was evaluated. Primary culture of cortical neurons and C6 glioma cells, which can express the same Na+/Ca2+ exchanger isoform (NCX1) of astrocytes, were exposed to chemical hypoxia and intracerebroventricularly cannulated rats were exposed to permanent middle cerebral artery occlusion (pMCAO.). It was recently reported that sodium nitroprusside (SNP), a nitric oxide (NO)-generating compound, possesses the ability to activate the Na+/Ca2+ exchanger in cultured rat astrocytes.3 On the other hand, the SNP molecule contains iron besides the NO group. This metal ion, mediating the transfer of electrons between the cellular redox compounds and appropriate disulfide-thiol groups of the NCX molecule, can stimulate antiporter activity.4 Therefore, we investigated whether: (a) SNP could prevent chemical hypoxia-induced C6 glioma cell death, (b) this neuroprotective action was due to a stimulation of the Na+/Ca2+ exchanger activity, and (c) these effects were due to the NO donor property or the iron-releasing effect of SNP. To extrapolate these in vitro observations on the role played by the Na+/Ca2+ exchanger during anoxia to in vivo models of cerebral ischemia, pMCAO was performed in male rats.

In this study, the temporal development of focal cerebral infarction induced by permanent middle cerebral artery occlusion (pMCAO) and the effects of piracetam, a derivative of gamma-aminobutyric acid widely used in clinical practice as a nootropic agent, on infarct area and volume were investigated. pMCAO caused a cerebral infarct whose size progressively increased after 3, 6, 9, and 24 h. Piracetam (125 mg/kg i.p.), administered 6, 9, and 22 h after pMCAO, did not reduce pMCAO-induced brain infarct area size detected at the 24th hour. By contrast, when this agent was administered at the doses of 250 and 500 mg/kg, it caused a marked reduction of the infarct area size. This reduction was observed in almost every brain slice affected by pMCAO, although statistical differences (p

A statistical mechanics theory of rubber-like elasticity in hydrogels characterized by explicitly non-Gaussian distribution functions (Laplace’s, Cauchy’s, and continuous Poisson’s in the exponential limit) of the end to end distribution is presented. Despite its formal complexity, the outcome of this approach leads to the formulation of reasonably simple models easily comparable with experimental data on polymer networks. In order to identify the most likely end-to-end length distribution in an arbitrary network, a theoretical-experimental approach based on Low Field NMR (LF-NMR) is proposed. Three different hydrogels are considered: agar 1 %, alginate 1 %, and scleroglucan 2 %.

Recent experiments report that slowly sheared noncolloidal particle suspensions unexpectedly exhibit rate(ω)-dependent complex viscosities in oscillatory shear, despite a constant relative viscosity in steady shear. Using a minimal hydrodynamic model, we show that van der Waals attraction gives rise to this behavior. At volume fractions φ=20-50%, the complex viscosities in both experiments and simulations display power-law reductions in shear, with a φ-dependent exponent maximum at φ=40%, resulting from the interplay between hydrodynamic, collision, and adhesive interactions. Furthermore, this rate dependence is accompanied by diverging particle diffusivities and pronounced cluster formations after repeated oscillations. Previous studies established that suspensions transition from reversible absorbing states to irreversible diffusing states when the oscillation amplitude exceeds a φ-dependent critical value γ0,φc. Here, we show that a second transition to irreversibility occurs below an ω-dependent critical amplitude, γ0,ωc≤γ0,φc, in the presence of weak attractions.

Manure from lactating and non-lactating water buffaloes was separately collected from a single dairy farm and anaerobically digested under mesophilic conditions in batch mode to produce biogas. This substrate, scarcely studied in the literature, showed two peculiarities regarding two fundamental parameters in the digestion processes: C/N ratio and initial pH. Typically, optimal C/N varies from 20 to 30, but in this work an almost negligible role of this ratio is observed. We demonstrated it by investigating a very large C/N interval, from 9.7 to 50.1, not by adding selected nutrients to the system, but exploiting the natural variation of the substrate. Concerning the pH, we show that also typically considered unfavorable conditions are feasible for this substrate. In fact, though neutral-basic initial pH is proved to be optimal to run the digestion process, in line with many other kinds of dungs, also acid initial pH leads to satisfactory CH4 yield. This is principally related to the capability of water buffalo manure of auto-modifying the pH to neutrality during the digestion, when initial pH of 5.0 and 6.0 are considered. This aspect may be relevant in co-digestion processes with acid wastes, since it may allow not adding neither a buffer, nor a pH regulator to the system. All the digestion conditions are separately tested with lactating and non-lactating water buffaloes and no statistical meaningful differences exist between the two kinds of cattle.

Background: It has been shown that many plant- or microbial-derived oligos and polysaccharides may prompt tissue repair. Among the different extracts that have been studied, the aqueous one of Triticum vulgare (TVE) that was obtained from a whole germinated plant has been proven to have different biological properties that are useful in the process of wound healing. Nevertheless, with the long tradition of its use in pharmaceutical cream and ointments, especially in Italy, a new protocol was recently proposed (and patented) to improve the extraction process. Methods: In a simplified in vitro model, human keratinocyte monolayers were scratched and used to run time lapse experiments by using time lapse video microscopy (TLVM) to quantify reparation rate while considering a dose&ndash, response effect. Contemporarily, the molecular mechanisms that are involved in tissue repair were studied. In fact, key biomarkers that are involved in remodeling, such as MMP-2 and MMP-9, and in matrix structure assembly, such as collagen I, elastin, integrin &alpha, V and aquaporin 3, were evaluated with gene expression analyses (RT-PCR) and protein quantification in western blotting. Results: All TVE doses tested on the HaCat-supported cell proliferation. TVE also prompted cell migration in respect to the control, correctly modulating the timing of metalloproteases expression toward a consistent and well-assessed matrix remodeling. Furthermore, TVE treatments upregulated and positively modulated the expression of the analyzed biomarkers, thus resulting in a better remodeling of dermal tissue during healing. Conclusions: The in vitro results on the beneficial effects of TVE on tissue elasticity and regeneration may support a better understanding of the action mechanism of TVE as active principles in pharmaceutical preparation in wound treatment.

Multiphase fluids and highly non-Newtonian fluids often show wall slip. The typical approach to reduce wall slip in experiments is to use roughened geometries, which are thin porous layers. However, the presence of the roughness introduces in itself an apparent wall slip due to the flow within the porous layer. To account for wall slip typically, measurements must be run at several gaps in a plate-plate device. With Newtonian fluids, the apparent wall slip can be conveniently accounted for in the measurements at a single gap since it can be accurately predicted using models describing the flow of Newtonian fluids through and over porous media. Here, we extend this approach to viscoelastic fluids by using Minale's model [Phys. Fluids 28, 023102 and 023103 (2016)] for the flow of second order fluids (SOFs) through and over a porous medium. In this work, we first validate the theoretical predictions and then propose an experimental protocol to measure a SOF with rough geometries by executing the experiments at a single chosen gap. Two Boger fluids are used as model SOFs, and three different rough geometries are considered: Two commercial crosshatched plates and a homemade pillared one. The apparent wall slip is shown to be reduced for the viscoelastic fluids, with respect to the Newtonian case, and agreement with the theoretical predictions is excellent., Journal of Rheology, 63 (4), ISSN:0148-6055

A typical example of viscoelastic matrices is represented by polymeric particles devoted to the controlled release of active agents (drugs) that swell when put in contact with an external solvent, typically a physiological medium. Although, in general, physiological fluids can be considered Newtonian, this is not always the case, let us consider, for example, the mucus present in different organs such lungs when affected by chronic obstructive disease (bacterial infections and cystic fibrosis, for instance). Swelling allows the release of the embedded drug due to the enlargement of the meshes of the polymeric network. The demand for more and more sophisticated drug delivery systems requires to theoretically study in high detail the mass transport phenomena involved in the swelling and release processes. The present study concerns with the mathematical modelling of both transport processes in the case of a viscoelastic matrix swollen by a viscoelastic fluid. While matrix viscoelasticity is accounted for by the generalized Maxwell model, a mean relaxation time accounts for fluid viscoelasticity. The model assumes that solvent uptake gives origin to an internal stress, due the polymeric network reaction to enlargement, able to affect solvent transport and thus, drug release. Despite the complexity connected to the theoretical description of stress and deformation in the swelling matrix, it is generally assumed that the stress state can be approximated by a scalar that can be viewed as an osmotically induced viscoelastic swelling pressure related to the trace of the stress tensor. At the same time, assuming incompressible materials and vanishing deformation gradient inside the matrix, deformation can be simply represented by a scalar quantity (the radial deformation in the case of spheres). Model simulations indicate that the higher the swelling solvent relaxation time, the lower the effect of matrix viscoelastic properties on mass transport phenomena

In rheometry rough geometries are often used to prevent wall-slip typically encountered with heterogeneous fluids. However, the fluid does not stand still within the geometry roughness and a residual wall-slip can be often measured. The problem can be treated as the flow through a porous medium that is here investigated when the fluid is non-Newtonian. We use a Boger fluid that is a good model for the Second Order Fluids and a commercial cross-hatched plate as rough geometry. The results obtained are in good qualitative agreement with predictions available in the literature and are promising for the development of a simple procedure to use rough geometries with viscoelastic fluids.