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Finite element analysis in design of DMLS mandible implants
Published in Fernando Moreira da Silva, Helena Bártolo, Paulo Bártolo, Rita Almendra, Filipa Roseta, Henrique Amorim Almeida, Ana Cristina Lemos, Challenges for Technology Innovation: An Agenda for the Future, 2017
T.C. Dzogbewu, L. Monaheng, I. Yadroitsava, W.B. du Preez, I. Yadroitsev
Titanium-based alloys have become the principal biomaterial for dental and orthopedic implants due to their biocompatibility, corrosion resistance and relative low Young’s Modulus as compare to other biometals (Kulkarni et al. 2014). Additive Manufacturing (AM) has the capacity to produce complex shapes, intrinsic engineered parts with the possibility of producing multimaterial objects which have made them the prime choice for high-tech industries. AM technologies such as Direct Metal Laser Sintering (DMLS) or Electron Beam Melting (EBM) are widely used for producing Ti6Al4V customized patient specific tailored devices and they have brought a dramatic change into dental and orthopedic surgery.
Biomaterials and Surface Modification
Published in Mohammad E. Khosroshahi, Applications of Biophotonics and Nanobiomaterials in Biomedical Engineering, 2017
Biometals are metal ions used in biology, biochemistry, and medicine. The metals copper, zinc, iron, and manganese are examples of metals that are essential for the normal functioning of the human body. The biocompatibility of the metallic implants is of significant importance and concern from safety point of view. Metal compounds and ions can also produce harmful effects on the body due to the toxicity of several types of metals (Stephen 2014). For example, arsenic works as a potent poison due to its effects as an enzyme inhibitor, disrupting ATP production (Singh et al. 2011). Also, metals can corrode in the hostile body environment, which effectively weakens the implant in a defined period of time. Above all, the corrosion products escape into the tissue, leading to set of undesirable and adverse effects. The first stainless steel used for as implant material was type 302, which is stronger the vanadium steel and more resistant to corrosion. The former is no longer used due to its inadequate corrosion resistance. The next generation of stainless steel contained molybdenum in order to enhance its corrosion resistance in salt water, which is a close model to body physiological fluid. This type of steel was called 316 L and in the 1950s its carbon content was reduced from 0.08% to 0.03% (Park and Lakes 1992). Chromium as a reactive element is a major component of corrosion-resistant stainless steel. But the chromium and its alloys can be passivated to give a better corrosion resistance. However, for the purpose of biomedical applications such as implants, austenitic stainless steels including 316 and 316 L are widely used. These materials are nonmagnetic and have better corrosion resistance compared to other types. The inclusion of molybdenum improves the resistance to pitting corrosion. Finally, in order to stabilize the austenitic phase at room temperature, nickel is also added to enhance the corrosion resistance.
Bromo-substituted Mn(II) and Mn(III)-tetraarylporphyrins: synthesis and properties
Published in Journal of Coordination Chemistry, 2018
Natalya Vasil’evna Chizhova, Olga Valentinovna Maltceva, Svetlana Veniaminovna Zvezdina, Nugzar Zhoraevich Mamardashvili, Oscar Iosifovich Koifman
Manganese is a biometal necessary for life of organisms [1]. A large number of works in this field are conducted at the intersection of chemistry, biology, and medicine. The variety of manganese porphyrin especially electronic structure of molecules, their spectral, electrochemical, and complex formation properties make it important to study these compounds in terms of the development of theoretical and applied aspects of coordination and bioorganic chemistry. Manganese is essential to perform functions of reproductive, central nervous, and endocrine systems. Manganese porphyrins possess the ability to bind free radicals. Mn(III)-porphyrins are usually the most important representative class of metalloporphyrins with catalytic activity in epoxidation of alkenes [2]. The oxidation of sulfides by hydroperite in the presence of the Mn(III)-tetra-(4-hydroxyphenyl)porphyrin was studied [3]. According to Miskelly and coworkers [4] and DeFreitas-Silva and coworkers [5], the Mn(III)-5-(3-bromo-4-amino)phenyl-10,15,20-tris-phenyl-2,3,7,8,12,13,17,18-octabromoporphyrin could be used as a biomimetic catalyst of cyclohexane oxidation [5]. Catalytic activity and oxidative stability of a series of pyridyl-substituted manganese porphyrins has been investigated [6].
Two Zn(II)-based coordination polymers: treatment effect on the cardiac arrest induced by anesthesia by regulating Sirt1 expression
Published in Inorganic and Nano-Metal Chemistry, 2021
Yuan Chen, Tian Yang, Jie Huang, Hui-Yuan Yong
Structure and design of metal-involved supramolecular architectures based on crystal engineering are currently of interest in the field of supramolecular chemistry and coordination chemistry. The increasing interest in this field is justified not only by their valuable unit structure, but also their potential applications in luminescence, catalysis and biochemistry, particularly in modern medicinal chemistry.[1–5] Among the series of compounds fabricated, the functional complexes attract great attention due to the potential drug value applications. Thus, selecting safe, efficient and biocompatible metal ions along with the organic ligands has become a crucial factor in the field of structural design, drug therapy and clinical applications.[6–10] Zinc is an important biometal essential for life, which is second only to iron in terms of its concentration in the biological systems and is present in more than 300 enzymes of living organisms. Zn(II)-based coordination complexes have proved to be potential anticancer agents with low in vivo toxicity, low side effects and perhaps new modes of action and cellular targets compared with the classical metallodrugs.[11] Apart from the anticancer activity, many Zn complexes of biological interest have been reported showing antiproliferative, antimicrobial and antifungal activity.[12–14] In this study, by applying a mixed-ligand approach, two new Zn(II)-containing coordination polymers (CPs) with the chemical formula of {Zn(TDC)(TPP)0.5·H2O}n (1) and {[Zn2(2,6-NDC)2(TPP)]·MeCN·3H2O}n (2) (TPP = 2,3,5,6-tetra(pyridin-4-yl)pyrazine, H2TDC = 2,5-thiophenedicarboxylic acid, 2,6-H2NDC = 2,6-naphthalic acid), have been synthesized by a semi-rigid tetrapyridine ligand and auxiliary dicarboxylic ligands. The as-prepared two compounds have been characterized by single-crystal X-ray diffraction, infrared spectroscopy (IR), thermogravimetric (TG) analyses and powder X-ray diffraction (PXRD). In biological research, their protective effect against cardiac arrest induced by anesthesia was evaluated. The results of the ELISA indicated that compound 1 could significantly reduce the content of cardiac troponin T and B brain natriuretic peptide, but not compound 2. In addition to this, the RT-PCR results suggested that compound 1 also showed a stronger promotion effect than compound 2 on the Sirt1 gene expression in the rat myocardial tissue.