Antibacterial Properties of Stainless Steel Coated on Ti6Al4V Alloy

open access journalTitanium alloys and stainless steeltype 316Lare used in biomedical applications due to their high corrosion resistance and good biocompatibility properties. In this study, a functionally graded material composed of titanium and stainless steel was fabricated usinga powder metallurgical technique. Ti6Al4V alloy powder was placed as a substrate into a graphite crucible and stainless steel powder was added as a thin layer on the Ti6Al4V powder. The two layers were consolidated in-situ using a uniaxial hot press. The sintering process was carried out at 1050 oC for 30 minutes under 50 MPa. The pressure was maintained during the whole sintering process. A disc shape compact of 20 mmdiameter and 5 mmthickness was obtained aftersintering. The samples were metallographically prepared and their antibacterial properties were evaluated. A strong bonding was observed between the Ti6Al4V substrate and the 316L stainless steel layer, and no bacteria were observed on the stainless steel surface

Solidification characteristics of atomized AlCu4Mg1-SiC composite powders

In this study, rapidly solidified metal matrix composite powders have been produced by PREP (Plasma rotating electrode process) atomization. AlCu4Mg1 alloy is used as the matrix material while SiC particles, with about 650 nm average particle size, are used as the reinforcement phase. The microstructural and solidification characteristics of composite particles are studied using optical and scanning electron microscope (SEM). The relationship between secondary dendrite arm spacing (SDAS) and particle diameter was examined, and these composite powders were found to have dendritic and equiaxed solidification with a fine eutectic phase. SDAS measurements using various sized particles show that secondary dendrite arm spacing slightly decreases with the decrease in particle size

Evaluation of iron and zinc levels in recurrent tonsillitis and tonsillar hypertrophy

WOS: 000372213200012PubMed ID: 26954864Objectives: The aim of this study is to look into the roles of iron and zinc metals in etiopathogenesis of recurrent tonsillitis and tonsillar hypertrophy by evaluating the levels of iron and zinc elements in the palatine tonsillar tissue. Methods: In total, 40 patients who underwent a tonsillectomy to treat recurrent tonsillitis and tonsillar hypertrophy were included in the study. Patients were classified into two groups, recurrent tonsillitis and tonsillar hypertrophy, determined by the results of clinical and histopathological examination. The levels of iron and zinc elements were determined for each tonsillar tissue sample. Results: There was a significant difference in the iron and zinc concentrations (p < 0.001) between the tonsillar hypertrophy and recurrent tonsillitis groups. The levels of iron and zinc were significantly lower in the recurrent tonsillitis group. Conclusions: This study suggests that low tissue concentrations of iron and zinc may lead to recurrent tonsillitis. (C) 2016 Elsevier Inc. All rights reserved

Pressure Assisted Bonding Process of Stainless Steel on Titanium Alloy Using Powder Metallurgy

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Titanium alloys have been widely used in many industrial applications. Nevertheless, efforts to improve their properties are continually increasing. One of the most effective routes to improve strength, hardness and wear resistance is to create a coating layer on the substrates. In the current study, stainless steel was selected for the in-situ joining and creating a continuous layer on the Ti6Al4V alloy. The Joining process was carried out at two different temperatures, 950 oC and 1050 oC, and the mechanical properties of the bonded materials were investigated employing hardness, bending strength and wear tests, while the bonding interface layer between the alloys powders was characterized by optical and scanning electron microscopes. The results showed that the higher the joining temperature, the wider the interfacial zone between the coating layer and substrate. The hardness and wear properties of the joint materials increased at 1050oC, while the bending stress was reduced and debonding was observed after the bending test. The chemical composition at the interface zone was identified by energy dispersive X-ray analysis, and the results showed high diffusion rates between the elements. As a result, the process used in the current study can be used for many titanium alloys, and their use in industrial applications can be increased

Effect of Si addition on microstructure and wear properties of Mg-Sn as-cast alloys

Effect of Si addition on microstructure, hardness and wear resistance of as cast Mg-5Sn and Mg-10Sn alloys were investigated. For this purpose alloys with wt.-% 0, 0.5, 1, 1.5 Si were cast using an induction furnace. Addition of Si to both alloys caused an increasement in the amount of intermetallic phases at the grain boundaries. Also refined grain structure was reported with increasing Si content in the cast alloys. Both increased amount of intermetallics and decreased grain size caused an increase in the hardness of the alloys. Wear resistance of the binary alloys first increased with Si addition and then decreased. Increased amounts of Si in the alloys caused crack formation during wear tests and decreased wear resistance. Sliding speed also has a dramatical effect on the wear resistance of the alloys. Increased sliding speed resulted with higher wear resistance. Worn surfaces of the alloys also investigated under scanning electron microscope to understand the wear mechanisms operated during wear tests

A young puerperal woman presenting to emergency department with severe dyspnea

Peripartum cardiomyopathy (PPCM) is an idiopathic cardiomyopathy presenting with heart failure (HF) secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery, where no other cause of HF is found. The symptoms and signs of this rare disorder mimic those of the physiological changes of pregnancy or other cardiovascular diseases. Consequently, its diagnosis is frequently delayed, which worsens an already poor prognosis. Here, we report a young adult who was diagnosed with PPCM, early, with the help of focused cardiac ultrasonography, performed after presenting to the emergency department with nonspecific respiratory complaints, including dyspnea and hemoptysis, which suggested at first pulmonary embolism. Keywords: Acute heart failure, Echocardiography, Cardiomyopathy, Ultrasoun

Characterisation of submerged powder injection into water using an in-line particle detection system

Particle behaviour during the downwards, pneumatic injection of powder into an aqueous medium (water) has been investigated by means of a new method which involves direct measurement by making use of an Aqueous Particle Sensor (APS) unit. Through this method, phenomena and parameters related to injection processes, such as gas-particle jet penetration distance, jet diameter, jet cone angle, particle dispersion and distribution within the liquid have been investigated both qualitatively and quantitatively. Flow observations comprised part of the experimental program for the purpose of confirming the characteristics of the "gas-only" and "gas-powder" injection regimes reported by previous workers.The effect of gas and powder flow rates (powder/gas loading ratio) in determining the injection regimes and particle behaviour within the liquid were the main parameters investigated.It was demonstrated that the jetting regime can be easily achieved as a result of increased momentum transfer from the particles to the gas phase. However, this required a high loading of particles. Entrainment of gas with the injected particles took place not only during coupled flow (jetting) but also during decoupled (bubbling) flow, such that some gas was always entrained by the particles and penetrated the liquid as a gas-particle jet, leaving large gas bubbles at the lance tip. It was further demonstrated that the gas flow rate had a greater effect on particle suspension within the liquid than did the powder flow rate

Production and characterization of Al-xNi in situ composites using hot pressing

In this study, a new metal matrix composite of aluminium was designed with the addition of nickel alloy particles. To produce in situ intermetallic formation, aluminium-nickel powder mixtures with different ratios ranging from 5 to 40 wt% Ni were consolidated at 550ºC for 15 minutes under 40 MPa pressure. The interlayer phase formed during sintering was determined using X-ray diffraction and energy dispersive X-ray spectroscopy. The effect of nickel and Al-Ni intermetallics on the mechanical properties of the material was studied. The results demonstrated that the addition of nickel enhanced the hardness and wear behaviour of aluminium by forming a strong bonding interface between the aluminium and nickel particles

A new side effect of synthetic cannabinoid use by the bucket (waterpipe) method: Acute respiratory distress syndrome (ARDS)

The use and content of synthetic canibinden (SCs) has been rapidly increased in the last decades. The complex content of these substances bring along a wide spectrum of side effects. In addition to the expected neuropsychological side effects of pleasure-inducing substances such as agitation, anxiety, panic attack and hallucinations, rare cases of cerebrovascular diseases, seizures, acute renal injury, myocardial infarction and chronic lung injury have also been previously reported.Here we report a 19-year -old male who was presented with acute respiratory distress syndrome (ARDS) within hours of inhaled SC use with the rarely preferred bucket method. There is limited information in the literature about pulmonary effects of SCs and we could not detect any other ARDS case that develoed within hours after consumption of SC with the bucket method