Effects of magnesium sulphate on liver ischemia/reperfusion injury in a rat model

Aim: To investigate the protective efficacy of magnesium sulphate in a model of rat liver ischemia-reperfusion (I/R) injury. Method: 32 adult female Wistar-Albino rats (250 to 350 g) were used in this experimental study. Rats were divided into 4 groups according to liver ischemia and magnesium sulfate application methods. Group 1 (C); control, group 2 (M); magnesium sulphate, group 3 (I/R); liver I/R, group 4 (I/R+M); I/R + magnesium sulphate treated. The blood samples were centrifuged for the study of aspartate aminotransferase (AST), alanine aminotransferase, prothrombin time (PT), international normalized ratio (INR) troponin I, total antioxidant status (TAS), total oxidant status (TOS) assays. The livers of the animals were removed at the end of the study and samples were taken for histopathological examination. Results: AST and INR values were significantly decreased in I/R+M group compared to I/R group. There was no significant difference in ALT values of the groups. Although not statistically significant, the TAS values were increased in I/R + M group compared to I/R group rats. In addition, the value of TOS was found to be lower in I/R + M group rats. In the histopathological examination, the mean values of apoptosis and necrosis were lower in the IR+M group compared to the IR group. Conclusion: The main finding of the present study suggested that magnesium sulphate pretreatment moderately decreased the liver damage through its anti-inflammatory and anti-oxidant effects in a rat model of liver I/R

Comparison of Renoprotective Effect of Dabigatran With Low-Molecular-Weight Heparin

WOS: 000373916700008PubMed ID: 25681331Objective: The susceptibility of tissue to ischemia-reperfusion (I/R) injury is a major obstacle to tissue regeneration and cellular survival. In this study, we investigated the possible renoprotective effect of dabigatran in an experimental renal I/R model. Method: A total of 25 rats were randomly divided into 5 equal groups. The control group was used to obtain basal values of oxidant and antioxidant biomarkers. The sham group was used to obtain renal prolidase and malondialdehyde (MDA) levels after renal ischemia (for 45 minutes) and reperfusion (for 1 hour). A standard diet was followed. Oral 15 mg/kg dabigatran etexilate was administrated to group I, intraperitoneal 250 U/kg enoxaparin sodium was administrated to group II, and intraperitoneal 250 U/kg bemiparin sodium was administrated to group III for 1 week before the renal I/R was performed. Renal tissue samples were obtained during the first hour of reperfusion to detect renal prolidase and MDA levels in these groups, after which the rats were euthanized. Results: Renal prolidase levels were significantly higher in the sham group compared with the control group (1834.2 982.3 U/g protein vs 238.8 +/- 43.6U/g protein; P = .001). Lower prolidase levels were observed in groups II (838.7 +/- 123.8 U/g protein) and III (1012.9 +/- 302.3 U/g protein), and the lowest prolidase levels occurred in group I (533.8 +/- 96.2 U/g protein; P < .05) when compared with the sham group. The MDA levels were significantly lower (P < .05) in groups I, II, and III (163.9 +/- 41.5, 185.4 +/- 51.0, and 138.2 +/- 22.6 mol/g protein, respectively) compared with the sham group. Conclusion: Dabigatran etexilate, a univalent direct thrombin inhibitor, may protect the renal tissue more effectively when compared to low-molecular-weight heparins

A Sustainable Approach to Produce Stiff, Super-Tough, and Heat-Resistant Poly(lactic acid)-Based Green Materials

Circumventing inherent embrittlement, poor heat resistance, and melt elasticity of poly(lactic acid) (PLA) without compromising its remarkable stiffness and strength has become a particular challenge in polymer science due to increasing demand for green materials in emerging applications of sustainable chemistry and engineering. Achieving this without using any high-cost reagent/additive and/or complex processing technique is another critical aspect for developing industrially viable alternatives to petroleum-based commodity plastics. Here we demonstrate that high-shear mixing of PLA with waste cross-linked polyurethanes and waste cellulose fibers allows for overcoming its inherent embrittlement, poor heat resistance, and melt elasticity without compromising its superior stiffness and strength while suggesting a sustainable way of recycling/reusing industrial wastes as high added-value additives. We therefore achieve to produce stiff, strong, super-tough, and heat-resistant PLA-based green materials, for instance, with an elastic modulus of 4 GPa at 25 degrees C (similar to 30% higher than that of pure PLA), a storage modulus of 312 MPa at 90 degrees C (similar to 44 times higher than that of pure PLA), a tensile strength of 65 MPa (comparable to that of PLA), and an impact strength (toughness) of 52 kJ/m(2) (similar to 2.3 times higher than that of pure PLA)

Poly(lactide)/cellulose nanocrystal nanocomposites by high-shear mixing

There is currently considerable interest in developing stiff, strong, tough, and heat resistant poly(lactide) (PLA) based materials with improved melt elasticity in response to the increasing demand for sustainable plastics. However, simultaneous optimization of stiffness, strength, and toughness is a challenge for any material, and commercial PLA is well-known to be inherently brittle and temperature-sensitive and to show poor melt elasticity. In this study, we report that high-shear mixing with cellulose nanocrystals (CNC) leads to significant improvements in the toughness, heat resistance, and melt elasticity of PLA while further enhancing its already outstanding room temperature stiffness and strength. This is evidenced by (i) one-fold increase in the elastic modulus (6.48 GPa), (ii) 43% increase in the tensile strength (87.1 MPa), (iii) one-fold increase in the strain at break (similar to 6%), (iv) two-fold increase in the impact strength (44.2 kJ/m(2)), (v) 113-fold increase in the storage modulus at 90 degrees C (787.8 MPa), and (vi) 10(3)-fold increase in the melt elasticity at 190 degrees C and 1 rad/s (similar to 10(5) Pa) via the addition of 30 wt% CNC. It is hence possible to produce industrially viable, stiff, strong, tough, and heat resistant green materials with improved melt elasticity through high-shear mixing

Structural, lithological, and geodynamic controls on geothermal activity in the Menderes geothermal Province (Western Anatolia, Turkey)

Western Turkey belongs to the regions with the highest geothermal potential in the world, resulting in significant electricity production from geothermal resources located predominantly in the Menderes Massif. Although geothermal exploitation is increasingly ongoing, geological, and physical processes leading to the emplacement of geothermal reservoirs are hitherto poorly understood. Several studies on the Menderes Massif led to different interpretations of structural controls on the location of hot springs and of the heat source origin. This paper describes geological evidence showing how heat is transmitted from the abnormally hot mantle to the geothermal reservoirs. On the basis of field studies, we suggest that crustal-scale low-angle normal faults convey hot fluids to the surface and represent the first-order control on geothermal systems. At the basin scale, connected on low-angle normal faults, kilometric high-angle transfer faults are characterized by dilational jogs, where fluids may be strongly focused. In addition, favourable lithologies in the basement (e.g., karstic marble) could play a critical role in the localization of geothermal reservoirs. Finally, a compilation of geochemical data at the scale of the Menderes Massif suggests an important role of the large mantle thermal anomaly, which is related to the Hellenic subduction. Heat from shallow asthenospheric mantle is suggested to be conveyed toward the surface by fluid circulation through the low-angle faults. Hence, geothermal activity in the Menderes Massif is not of magmatic origin but rather associated with active extensional tectonics related to the Aegean slab dynamics (i.e., slab retreat and tearing)

High-performance green composites of poly(lactic acid) and waste cellulose fibers prepared by high-shear thermokinetic mixing

Green composites of poly(lactic acid) (PLA) and waste cellulose fibers (WCF) were produced by using a facile technique comprising high-shear mixing within relatively short processing times that facilitates the ease of processing of such materials and ensures the homogeneous dispersion of such fibers in thermoplastics due to shear rates as high as 5200 rpm. Key parameters, such as optimal concentrations, homogeneous dispersion, direct and indirect mechanical contributions of the fibers, interfacial interactions, and crystallinity of the PLA matrix, were examined for the sustainable production of PLA/WCF green composites with enhanced stiffness, strength, toughness, and impact resistance. Briefly, around one-fold, 50%, and 20% increase in the elastic modulus, tensile strength, and impact strength of PLA, respectively, were achieved by the addition of 30 wt % WCF. In addition, an 87% increase in the impact strength of PLA was also achieved by the incorporation of 5 wt % WCF

Computer-Aided Patient-Specific Coronary Artery Graft Design Improvements Using CFD Coupled Shape Optimizer.

This study aims to (i) demonstrate the efficacy of a new surgical planning framework for complex cardiovascular reconstructions, (ii) develop a computational fluid dynamics (CFD) coupled multi-dimensional shape optimization method to aid patient-specific coronary artery by-pass graft (CABG) design and, (iii) compare the hemodynamic efficiency of the sequential CABG, i.e., raising a daughter parallel branch from the parent CABG in patient-specific 3D settings. Hemodynamic efficiency of patient-specific complete revascularization scenarios for right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCX) bypasses were investigated in comparison to the stenosis condition. Multivariate 2D constraint optimization was applied on the left internal mammary artery (LIMA) graft, which was parameterized based on actual surgical settings extracted from 2D CT slices. The objective function was set to minimize the local variation of wall shear stress (WSS) and other hemodynamic indices (energy dissipation, flow deviation angle, average WSS, and vorticity) that correlate with performance of the graft and risk of re-stenosis at the anastomosis zone. Once the optimized 2D graft shape was obtained, it was translated to 3D using an in-house "sketch-based" interactive anatomical editing tool. The final graft design was evaluated using an experimentally validated second-order non-Newtonian CFD solver incorporating resistance based outlet boundary conditions. 3D patient-specific simulations for the healthy coronary anatomy produced realistic coronary flows. All revascularization techniques restored coronary perfusions to the healthy baseline. Multi-scale evaluation of the optimized LIMA graft enabled significant wall shear stress gradient (WSSG) relief (~34%). In comparison to original LIMA graft, sequential graft also lowered the WSSG by 15% proximal to LAD and diagonal bifurcation. The proposed sketch-based surgical planning paradigm evaluated the selected coronary bypass surgery procedures based on acute hemodynamic readjustments of aorta-CA flow. This methodology may provide a rational to aid surgical decision making in time-critical, patient-specific CA bypass operations before in vivo execution.</p