Modulation of Contact System Proteases by Glycosaminoglycans SELECTIVE ENHANCEMENT OF THE INHIBITION OF FACTOR XIa

Abstract We investigated the influence of dextran sulfate, heparin, heparan sulfate, and dermatan sulfate on the inhibition of FXIa (where FXIa is activated factor XI, for example), FXIIa, and kallikrein by C1 inhibitor, α1-antitrypsin, α2-antiplasmin, and antithrombin III. The second-order rate constants for the inhibition of FXIa by C1 inhibitor, α1-antitrypsin, α2-antiplasmin, and antithrombin III, in the absence of glycosaminoglycans, were 1.8, 0.1, 0.43, and 0.32 × 103 M−1 s−1, respectively. The rate constants of the inactivation of FXIa by C1 inhibitor and by antithrombin III increased up to 117-fold in the presence of glycosaminoglycans. These data predicted that considering the plasma concentration of the inhibitors, C1 inhibitor would be the main inhibitor of FXIa in plasma in the presence of glycosaminoglycans. Results of experiments in which the formation of complexes between serine protease inhibitors and FXIa was studied in plasma agreed with this prediction. Glycosaminoglycans did not enhance the inhibition of α-FXIIa, β-FXIIa, or kallikrein by C1 inhibitor. Thus, physiological glycosaminoglycans selectively enhance inhibition of FXIa without affecting the activity of FXIIa and kallikrein, suggesting that glycosaminoglycans may modulate the biological effects of contact activation, by inhibiting intrinsic coagulation without affecting the fibrinolytic potential of FXIIa/kallikrein

FEM simulation of a crack propagation in a round bar under combined tension and torsion fatigue loading

An edge crack propagation in a steel bar of circular cross-section undergoing multiaxial fatigue loads is simulated by Finite Element Method (FEM). The variation of crack growth behaviour is studied under axial and combined in phase axial+torsional fatigue loading. Results show that the cyclic Mode III loading superimposed on the cyclic Mode I leads to a fatigue life reduction. Numerical calculations are performed using the FEM software ZENCRACK to determine the crack path and fatigue life. The FEM numerical predictions have been compared against corresponding experimental and numerical data, available from literature, getting satisfactory consistencyN/

Experimental investigation on flow boiling heat transfer and pressure drop of refrigerants R32 and R290 in a stainless steel horizontal tube

The purpose of this paper is to present new flow boiling heat transfer and pressure drop data in a single, horizontal smooth stainless steel tube of 6.0 mm internal diameter, in which R32 and R290 (propane) are employed as working fluids. The cross sectional average heat transfer coefficients are obtained by measuring the temperatures at the top, bottom, left and right sides of the channel. The experimental trends are analyzed for different operating conditions in terms of mass velocity (from 150 to 300 kg/(m2 s)) and heat flux (from 10 to 40 kW/m2). The saturation temperature is fixed to 25 °C for the heat transfer data and to 25 and 35 °C for the pressure drop experiments. The effects of the operative parameters and of the working fluids on local heat transfer coefficients and frictional pressure drop are discussed and the experimental data are finally compared with some of the available correlations taken from scientific literature

FEM Substructuring for the Vibrational Characterization of a Petrol Engine

In this work the vibrational behavior of a 4-cylinder, 4-stroke, petrol engine has been simulated by leveraging on a reduced modelling strategy, based on the Component Mode Synthesis (CMS), adopted to reduce the size of the full FEM model of the engine. The FEM model of the engine, comprising all of its sub-components, has been preliminary characterized from the vibrational standpoint; subsequently, the CMS has been adopted in order to reduce the FEM model size. Frequency Response Function (FRF) analyses have been used to identify the resonant frequencies and mode shapes of the different FEM models, and the so-obtained results have been compared showing a very good agreement. The reduced model has been able to reproduce with a high accuracy the vibration response at the engine mounts. The adopted reduced modelling strategy turned out to be effective in lowering the computational burden, keeping, at the same time, an accurate replication of the engine vibrational behavior. Runtimes have been significantly reduced from 24 hours for the full FEM model to less than 2 hours for the reduced model

Impact Laws And Decrees On Activities: The Ilda Study

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FEM simulation of a crack propagation in a round bar under combined tension and torsion fatigue loading

An edge crack propagation in a steel bar of circular cross-section undergoing multiaxial fatigue loads is simulated by Finite Element Method (FEM). The variation of crack growth behaviour is studied under axial and combined in phase axial+torsional fatigue loading. Results show that the cyclic Mode III loading superimposed on the cyclic Mode I leads to a fatigue life reduction. Numerical calculations are performed using the FEM software ZENCRACK to determine the crack path and fatigue life. The FEM numerical predictions have been compared against corresponding experimental and numerical data, available from literature, getting satisfactory consistency

Pseudo-dipeptide bearing α,α-difluoromethyl ketone moiety as electrophilic warhead with activity against coronaviruses

The synthesis of α-fluorinated methyl ketones has always been challenging. New methods based on the homologation chemistry via nucleophilic halocarbenoid transfer, carried out recently in our labs, allowed us to design and synthesize a target-directed dipeptidyl α,α-difluoromethyl ketone (DFMK) 8 as a potential antiviral agent with activity against human coronaviruses. The abil-ity of the newly synthesized compound to inhibit viral replication was evaluated by a viral cyto-pathic effect (CPE)-based assay performed on MCR5 cells infected with one of the four human coro-naviruses associated with respiratory distress, i.e., hCoV-229E, showing antiproliferative activity in the micromolar range (EC50 = 12.9 ± 1.22 μM), with a very low cytotoxicity profile (CC50 = 170 ± 3.79 μM, 307 ± 11.63 μM, and 174 ± 7.6 μM for A549, human embryonic lung fibroblasts (HELFs), and MRC5 cells, respectively). Docking and molecular dynamics simulations studies indicated that 8 efficaciously binds to the intended target hCoV-229E main protease (Mpro). Moreover, due to the high similarity between hCoV-229E Mpro and SARS-CoV-2 Mpro, we also performed the in silico analysis towards the second target, which showed results comparable to those obtained for hCoV-229E Mpro and promising in terms of energy of binding and docking pose

Pseudo-dipeptide bearing α,α-difluoromethyl ketone moiety as electrophilic warhead with activity against coronaviruses

The synthesis of α-fluorinated methyl ketones has always been challenging. New methods based on the homologation chemistry via nucleophilic halocarbenoid transfer, carried out recently in our labs, allowed us to design and synthesize a target-directed dipeptidyl α,α-difluoromethyl ketone (DFMK) 8 as a potential antiviral agent with activity against human coronaviruses. The ability of the newly synthesized compound to inhibit viral replication was evaluated by a viral cytopathic effect (CPE)-based assay performed on MCR5 cells infected with one of the four human coronaviruses associated with respiratory distress, i.e., hCoV-229E, showing antiproliferative activity in the micromolar range (EC50 = 12.9 ± 1.22 µM), with a very low cytotoxicity profile (CC50 = 170 ± 3.79 µM, 307 ± 11.63 µM, and 174 ± 7.6 µM for A549, human embryonic lung fibroblasts (HELFs), and MRC5 cells, respectively). Docking and molecular dynamics simulations studies indicated that 8 efficaciously binds to the intended target hCoV-229E main protease (Mpro). Moreover, due to the high similarity between hCoV-229E Mpro and SARS-CoV-2 Mpro, we also performed the in silico analysis towards the second target, which showed results comparable to those obtained for hCoV-229E Mpro and promising in terms of energy of binding and docking pose