A stabilized finite element method for finite-strain three-field poroelasticity

We construct a stabilized finite-element method to compute flow and finitestrain deformations in an incompressible poroelastic medium. We employ a three- field mixed formulation to calculate displacement, fluid flux and pressure directly and introduce a Lagrange multiplier to enforce flux boundary conditions. We use a low order approximation, namely, continuous piecewise-linear approximation for the displacements and fluid flux, and piecewise-constant approximation for the pressure. This results in a simple matrix structure with low bandwidth. The method is stable in both the limiting cases of small and large permeability. Moreover, the discontinuous pressure space enables efficient approximation of steep gradients such as those occurring due to rapidly changing material coefficients or boundary conditions, both of which are commonly seen in physical and biological applications

125 GeV Higgs Boson from t-b-tau Yukawa Unification

We identify a class of supersymmetric SU(4)_c x SU(2)_L x SU(2)_R models in which imposing essentially perfect t-b-tau Yukawa coupling unification at M_GUT yields a mass close to 122-126 GeV for the lightest CP-even (SM-like) Higgs boson. The squark and gluino masses in these models exceed 3 TeV, but the stau and charginos in some cases can be considerably lighter. We display some benchmark points corresponding to neutralino-stau and bino-wino coannihilations as well as A-resonance. The well-known MSSM parameter tan beta is around 46-52.Comment: 16 pages, 4 figure

Development of solid waste management system for Adana metropolitan municipality

Adana is a major agricultural and commercial center in southern Turkey. Adana is one of the first industrialized as well as one of the most economically developed cities of Turkey. The main aim of this project is to develop a new infrastructure for integrated solid waste management for Adana Metropolitan Municipality, including Yedigöze Union. New transfer stations have been located in Yedigöze Union to transfer all collected solid wastes to Adana Metropolitan Municipality Landfill Site for recycling and disposal. All plastic materials, including medical wastes, collected from Adana Metropolitan Municipality and Yedigöze Union will be transferred to a thermal and catalytic cracking unit for producing plastic fuel. All medical wastes will be sterilized and converted to plastic fuel without any Medical Waste Sterilization Unit. Experiments have shown that plastic fuel can be blended with 10% of diesel fuel and can be used for waste collection truck without any modification. © 2018, Springer International Publishing AG, part of Springer Nature

Relevance of inhomogeneous–anisotropic models of human cortical bone: a tibia study using the finite element method

Cortical bone is an inhomogeneous and anisotropic tissue subjected to large loads during typical daily activities. While studies assuming isotropic material properties are frequent, anisotropy and inhomogeneity of cortical bone have been rarely taken into account. Moreover, the question, whether an assumption of anisotropy and inhomogeneity has an impact in the mechanical analysis of cortical bone, has not been explored in the literature. This study explores the relevance of anisotropy in human cortical bone. The cortical bone model has been divided into six radial regions and a different set of orthotropic material properties has been assigned to each region. This inhomogeneous and anisotropic elastic tibia model has been compared with a corresponding isotropic model under various loading modes using the finite element method. In particular, the variation in the maximum von Mises stress and strain values has been observed along the bone axis. We have observed that the isotropic model may overestimate the maximum von Mises strain up to 15% under pure compression and underestimate up to 50% under pure torsion relative to the inhomogeneous–anisotropic model. Our results suggest that consideration of anisotropy and inhomogeneity of the bone may make a significant difference in the predicted maximum von Mises strain values, which can be important for strain-based damage accumulation studies and fracture risk evaluation. © 2016 The Author(s). Published by Taylor & Francis

A theoretical and experimental investigation of lateral deformations in a unilateral external fixator

The objective of this work is to set up, validate, and analyze a theoretical model of an external fixator for its deformation characteristics in order to draw reliable conclusions relevant to the design and effective clinical implementation of such medical devices. External fixators are mechanical devices widely used in the treatment of fractured bones and correction of limb deformities. Lateral deformation at the fracture site is known to delay bone healing, and investigation of lateral deformation characteristics of such devices experiencing forces acting perpendicular to the bone axis is important from the standpoint of their design as well as their clinical effectiveness. A mathematical model of a three-dimensional (3D) unilateral fixator with multipin fragment attachments has been developed using Castigliano's method. The relative lateral deformations of the fragment ends at the fracture site induced by loads applied perpendicular to bone axes are calculated with the model. The model has been subjected to experimental verification for a uniplanar unilateral external fixator under comparable conditions with the theory. It has been found out that the effects of fixator size, shape, and geometry on the level of relative lateral displacement of the fracture site are similar in both the theoretical and experimental models. Stiffness is a maximum if the force is applied in the same plane as the proximal pin plane. Placing the distal pin group at a 90 deg position relative to the proximal pin plane has been observed to increase the stiffness about 10%. In loading directions perpendicular to proximal the pin plane, stiffness is minimum. The angle difference between the load direction and the resulting displacement direction follows a sinusoidal pattern with an amplitude of 10 deg for loading angles in the 0-180 deg range. Selecting the distance of proximal pins to the fracture site smaller than the distance of distal pins to the fracture site has been found to decrease relative lateral deformation. The model and the experiment have simultaneously demonstrated that lower values of effective pin lengths and higher values of pin connector lengths lead to higher stiffness. Increasing the number of pins also contributes to the higher values of fixator stiffness. Copyright © 2007 by ASME

Phytochemical and Bioactivity Analysis of Several Methanolic Extracts of Nine Bryophytes Species

Bryophytes are a class of organisms found all over the globe except the sea. They can grow on different surfaces and are known for their fragrant aromas and strong hot and bitter taste. Bryophytes have been used in traditional Chinese medicine for the treatment of many pathological conditions. In the current study, we describe the bioactivities present in methanolic extracts obtained from 9 species of bryophytes. Plant samples were dried and extracted in a water/methanol solution which was explored for flavonoid and phenolic content. Afterwards, the extracts were analyzed for their potential bioactivities including DPP4 inhibition, metal chelation, antioxidant, and antiglycation activities. Results indicate that the methanolic extracts of each species showed high effectiveness for different bioactivities. The current findings suggest these bryophytes as promising source of therapeutics against oxidative stress, hypertension, and diabetes

Rho-kinase expression and its contribution to the control of perfusion pressure in the isolated rat mesenteric vascular bed

PubMedID: 14757149Rho-kinase expression was investigated in the rat mesenteric artery and the effects of its inhibitors, (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl) cyclohexanecarboxamide dihydrochloride monohydrate (Y-27632) and fasudil (HA-1077), were examined on the increase in perfusion pressure induced by two different receptor agonists, namely the ?-adrenoceptor agonist, phenylephrine and, the endothelin ETA and ETB receptor agonist, endothelin-1. Y-27632 and fasudil produced a concentration-dependent decrease in perfusion pressure. There was no difference between the concentration-response lines of these two inhibitors. The maximum decrease in the perfusion pressure induced by 10-5 M Y-27632 was 85.8±3. 7% when the tone was increased by phenylephrine. However, it was 48.1±5.4% (P<0.001) when the perfusion pressure was elevated by endothelin-1. Saponin perfusion (100 mg l-1, for 10 min), which abolished acetylcholine-induced relaxation, did not significantly modify the Y-27632-elicited relaxation. Western blot analysis revealed that rat mesenteric artery expresses Rho-kinase protein with a molecular weight of approximately 160 kDa. These results show that Rho-kinase enzyme is expressed in rat mesenteric artery and that it contributes to the control of vascular resistance. Moreover, endothelium removal had no marked effect on the vasodilatation induced by Y-27632. In addition, the endothelin-1-induced vasoconstriction was more resistant to the Rho-kinase inhibitors than was that induced by phenylephrine, probably because excitatory endothelin receptors are associated with this signal transduction pathway at a different level from that of ?-adrenoceptors. © 2003 Elsevier B.V. All rights reserved.K.B./TÜBA-GEBİP/2002-1-5This work has been supported by the Turkish Academy of Sciences, in the framework of the Young Scientist Award Program (K.B./TÜBA-GEBİP/2002-1-5). The authors are indebted to E. Özveren, H. Kubat and B. Korkmaz for their help during Western blotting