Behavior of plasma/insulin, somatropin and NEFA after intravenous administration of tolbutamide in hepatic cirrhosis

Cirrhotics presented higher insulin production, in the presence of a drop in glycaemia significantly less than controls, following 1 g of tolbutamide i.v. The drug also brought on a rapid drop in NEFA and a rise in plasma growth hormone. The pathogenesis of altered glucose tolerance in liver cirrhosis is discussed.     

Properties of polyethylene-polypropylene blends

High-density polyethylene (PE)-isotactic polypropylene (PP) blends have been characterized by a number of techniques such as wide-angle X-ray scattering, differential scanning calorimetry, picnometry, swelling in n-hexane and finally stress-strain tensile elongation. All the measurements have been performed on cilindrical shaped specimens, obtained directly by extrusion. The specimens show a complete random orientation of the crystallites of both the components. No co-crystallization phenomenon are observed. The melting point of both PE and PP decreases slightly with increasing concentration of the second component. The fractional crystallinity of PE decreases and that of PP increases with respect to the corresponding homopolymer values with increase in the concentration of the companion polyolefin. Such an effect is related to morphological kinetic effects and to different rates of crystallization of the two components, during the non-isothermal crystallization process following extrusion. Young's modulus, E is proportional to the overall fractional crystallinity. The ultimate properties show a synergistic effect due to the strong interactions between the crystallites and their tie molecules of the two PE and PP distinct phases. Finally, it is to be remarked that the results obtained in this paper, especially with respect to the ultimate properties, are quite different from those reported by other authors. This can be attributed to the different processing conditions used for obtaining the present blend specimens. Such conditions are certainly very important in determining particular blend morphologies which will determine in turn the properties of the analysed samples.     

Mechanical and swelling properties of polystyrene-polyolefin blends

Differential scanning calorimetry and swelling characterization have been extended to low density polyethylene-polystyrene blends. The thermal data reveal high incompatibility between the two components in the blend. Swelling measurements in the state of quasi-equilibrium show a marked anisotropy of the cylindrical extruded specimens. Mechanical measurements in the tensile mode were carried out at room temperature on blends of the same atactic polystyrene with each of four polyolefins with increasing side-chains featured in a previous work. As the composition is varied from the pure polystyrene to the pure polyolefin the stress-strain curve changes gradually from one exhibiting brittle fracture to one showing increasingly ductile yield. At a critical concentration that ranges generally from 30 up to 50% polystyrene there is clearly an inversion of phases. Below such value the blend consists of a polyolefin matrix with polystyrene fibrils oriented in the direction of extrusion, as inferred by the swelling data. Beyond this critical composition the blends consist of a glassy polystyrene matrix with polyolefin inclusions. In the latter case the anisotropy is due to the cylindrical shape of the entire specimen.     

Blends of poly(ethylene oxide) samples of different molecular weights: thermal and mechanical properties

Differential scanning calorimetry and mechanical measurements have been performed on binary poly(ethylene oxide) blends of different molecular weight samples. Some thermodynamic and mechanical properties, such as the melting point and the ultimate stress and strain are strongly affected by blend composition. The enthalpy of fusion and the Young's modulus, however, vary only slightly over the entire range of composition. Also the time for dissolution in water, at two different temperatures, has been measured on blends made from the lowest and the highest molecular weight components.The results indicate that by blending two different molecular weight samples, even of the same polymer, it is possible to influence the physical properties of the relative blends, so obtaining improvements of technological importance.     

Discovering expressive process models by clustering log traces

Process mining techniques have recently received notable attention in the literature; for their ability to assist in the (re)design of complex processes by automatically discovering models that explain the events registered in some log traces provided as input. Following this line of research, the paper investigates an extension of such basic approaches, where the identification of different variants for the process is explicitly accounted for, based on the clustering of log traces. Indeed, modeling each group of similar executions with a different schema allows us to single out "conformant" models, which, specifically, minimize the number of modeled enactments that are extraneous to the process semantics. Therefore, a novel process mining framework is introduced and some relevant computational issues are deeply studied. As finding an exact solution to such an enhanced process mining problem is proven to require high computational costs, in most practical cases, a greedy approach is devised. This is founded on an iterative, hierarchical, refinement of the process model, where, at each step, traces sharing similar behavior patterns are clustered together and equipped with a specialized schema. The algorithm guarantees that each refinement leads to an increasingly sound mDdel, thus attaining a monotonic search. Experimental results evidence the validity of the approach with respect to both effectiveness and scalability.     

Solving abduction by computing joint explanations

An extension of abduction is investigated where explanations are jointly computed by sets of interacting agents. On the one hand, agents are allowed to partially contribute to the reasoning task, so that joint explanations can be singled out even if each agent does not have enough knowledge for carrying out abduction on its own. On the other hand, agents maintain their autonomy in choosing explanations, each one being equipped with a weighting function reflecting its perception about the reliability of sets of hypotheses. Given that different agents may have different and possibly contrasting preferences on the hypotheses to be chosen, some reasonable notions of agents’ agreement are introduced, and their computational properties are thoroughly studied. As an example application of the framework discussed in the paper, it is shown how to handle data management issues in Peer-to-Peer systems and, specifically, how to provide a repair-based semantics to inconsistent ones.      

A 2-D Reservoir Routing Model: Sedimentation History of Abbeystead Reservoir, U.K.

A physically based two-dimensional model is applied to the case-study site of Abbeystead Reservoir, U.K. The model, developed fordensity currents, solves the Navier-Stokes equation coupled to ageneral sediment transport equation. Water flow and sediment motion are determined by reference to dimensionless Reynolds andRichardson numbers. An additional dimensionless parameter, a,determines suspended and/or bedload sediment transport rates. Theperformance of the model is considered in relation to data obtained from repeated bathymetric surveys (1876–1991) for Abbeystead Reservoir, which provides an exceptionally detailed long-term record of sedimentation rates and deposition patterns.The suitability of the adopted two-dimensional scheme is relatedto the local morphology of the reservoir and the time-scale of the delta propagation process. First results show good agreementbetween the numerical simulations and the field data. The modelis able to reproduce both the dynamics of delta growth and the quasi-equilibrium delta form reached as the infilling process nears completion.     

Extracellular Matrix Composition Modulates the Responsiveness of Differentiated and Stem Pancreatic Cancer Cells to Lipophilic Derivate of Gemcitabine

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Gemcitabine (GEM) is used as the gold standard drug in PDAC treatment. However, due to its poor efficacy, it remains urgent to identify novel strategies to overcome resistance issues. In this context, an intense stroma reaction and the presence of cancer stem cells (CSCs) have been shown to influence PDAC aggressiveness, metastatic potential, and chemoresistance. Methods: We used three-dimensional (3D) organotypic cultures grown on an extracellular matrix composed of Matrigel or collagen I to test the effect of the new potential therapeutic prodrug 4-(N)-stearoyl-GEM, called C18GEM. We analyzed C18GEM cytotoxic activity, intracellular uptake, apoptosis, necrosis, and autophagy induction in both Panc1 cell line (P) and their derived CSCs. Results: PDAC CSCs show higher sensitivity to C18GEM treatment when cultured in both two-dimensional (2D) and 3D conditions, especially on collagen I, in comparison to GEM. The intracellular uptake mechanisms of C18GEM are mainly due to membrane nucleoside transporters’ expression and fatty acid translocase CD36 in Panc1 P cells and to clathrin-mediated endocytosis and CD36 in Panc1 CSCs. Furthermore, C18GEM induces an increase in cell death compared to GEM in both cell lines grown on 2D and 3D cultures. Finally, C18GEM stimulated protective autophagy in Panc1 P and CSCs cultured on 3D conditions. Conclusion: We propose C18GEM together with autophagy inhibitors as a valid alternative therapeutic approach in PDAC treatment.     

Numerical evaluation of temperature fields and residual stresses in butt weld joints and comparison with experimental measurements

This paper presents a novel numerical model, based on the finite element (FE) method, for the simulation of a welding process aimed to make a two‐pass V‐groove butt joint, paying attention on the prediction of residual stresses and distortions. The ‘element birth and death’ technique for the simulation of the weld filler supply has been considered within this paper. The main advancements with respect to the state of the art herein proposed concern: (i) the development of a modelling technique able to simulate the plates interaction during the welding operation when an only plate is modelled. This phenomenon is usually neglected in literature; (ii) the heat amount is supplied to the FEs as volumetric generation of the internal energy, allowing overcoming the time‐consuming calibration phase needed to use the Goldak's model, commonly adopted in literature. Predicted results showed a good agreement with experimental ones.