The ELID Grinding of CoCrMo Alloy Bioprosthesis and the Formation Mechanism of its Corrosion-Resistant Oxide Layer

2018 ◽  
Vol 934 ◽  
pp. 140-144 ◽  
Author(s):  
Ji Cai Kuai ◽  
Cheng Ran Jiang ◽  
Jiang Wei Wang ◽  
Dmitrii V. Ardashev
Keyword(s):  
Oxide Layer ◽  
Formation Mechanism ◽  
Low Cost ◽  
Medical Field ◽  
Cocrmo Alloy ◽  
Corrosion Resistant ◽  
Elid Grinding ◽  
Grinding Method ◽  
Biological Environment

CoCrMo alloy is widely used in the medical field to make Biomedical prosthesis,But it is difficult to process resulting in the high cost of Biomedical prosthesis, Find an efficient and low-cost processing method has become a problem to be solved. In this paper, CoCrMo alloy Biomedical prosthesis were fabricated by Electrolytic In-process Dressing grinding. We studied the ELID grinding performance, grinding force, surface quality and the formation mechanism of Corrosion-resistant oxide layer of CoCrMo alloy by using dynamometer, roughness tester, XRD and SEM. It is proposed that the ELID grinding method forms an oxide layer on the surface of the prosthesis, which increases the corrosion resistance and biocompatibility of the prosthesis so that it can be better adapt to the biological environment in vivo. It was further confirmed that the ELID grinding method is an effective method for manufacturing CoCrMo Alloy Bioprosthesis.

Surface Finishing for Biomaterials: Application of the Elid Grinding Method

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1395-1400 ◽  
Author(s):  
Masayoshi Mizutani ◽  
Jun Komotori ◽  
Jin Nagata ◽  
Kazutoshi Katahira ◽  
Hitoshi Ohmori
Keyword(s):  
Oxide Layer ◽  
Ground Surface ◽  
Surface Finishing ◽  
Oxide Layers ◽  
Elid Grinding ◽  
Grinding Method ◽  
Transmission Electron ◽  
Finished Surface ◽  
Thick Oxide Layer

Conventional biomaterials, such as titanium alloys, require enhanced chemical stability and wear resistance, which are dependent on the quality of the surficial oxide layer. However, it is very difficult to produce a sufficiently homogenous oxide layer by polishing using isolation abrasive alone. In our previous study, we proposed a new electrical grinding method (ELID grinding). The process improves oxide formation on the finished surface, resulting in finished surfaces with very thick and potentially stable oxide layers. In this study, to ensure the fabrication of surface with desirable characteristics for biomaterials, three types of specimens, which were processed with different surface finishing methods were prepared. Processed surfaces were analyzed by using an Energy Dispersive X-ray analyzer (EDX). To measure the thickness of surface oxide layers, detailed observation were performed by using a Transmission Electron Microscope (TEM). Although the ELID ground surface shows a higher value of surface roughness, excellent corrosion resistance was observed as compared with the samples finished by polishing. This is because of the formation of a thick oxide layer on the finished surface by ELID grinding. Consequently, ELID grinding appears to offer significant future promise for use in biomaterials and other engineering components subjected to the corrosion process.

scholarly journals How protein coronas determine the fate of engineered nanoparticles in biological environment

2017 ◽  
Vol 68 (4) ◽  
pp. 245-253 ◽  
Author(s):  
Ivona Capjak ◽  
Sandra Šupraha Goreta ◽  
Darija Domazet Jurašin ◽  
Ivana Vinković Vrček
Keyword(s):  
Biological Fluids ◽  
Protein Corona ◽  
Engineered Nanoparticles ◽  
Biological Molecules ◽  
Diagnostic Tools ◽  
Medical Field ◽  
Dynamic Nature ◽  
Cell Tissue ◽  
Biological Environment

AbstractNanomedicine is a booming medical field that utilises nanoparticles (NPs) for the development of medicines, medical devices, and diagnostic tools. The behaviour of NPs in vivo may be quite complex due to their interactions with biological molecules. These interactions in biological fluids result in NPs being enveloped by dynamic protein coronas, which serve as an interface between NPs and their environment (blood, cell, tissue). How will the corona interact with this environment will depend on the biological, chemical, and physical properties of NPs, the properties of the proteins that make the corona, as well as the biological environment. This review summarises the main characteristics of protein corona and describes its dynamic nature. It also presents the most common analytical methods to study the corona, including examples of protein corona composition for the most common NPs used in biomedicine. This knowledge is necessary to design NPs that will create a corona with a desired efficiency and safety in clinical use.

A technique for protecting delicate specimens during processing

1989 ◽  
Vol 47 ◽  
pp. 982-983
Author(s):  
R.J. Mount ◽  
R.V. Harrison
Keyword(s):  
Basilar Membrane ◽  
Low Cost ◽  
Organ Of Corti ◽  
Region Of Interest ◽  
Sensory Epithelium ◽  
Physical Damage ◽  
Air Drying ◽  
Specimen Handling ◽  
Two Component

The sensory end organ of the ear, the organ of Corti, rests on a thin basilar membrane which lies between the bone of the central modiolus and the bony wall of the cochlea. In vivo, the organ of Corti is protected by the bony wall which totally surrounds it. In order to examine the sensory epithelium by scanning electron microscopy it is necessary to dissect away the protective bone and expose the region of interest (Fig. 1). This leaves the fragile organ of Corti susceptible to physical damage during subsequent handling. In our laboratory cochlear specimens, after dissection, are routinely prepared by the O-T- O-T-O technique, critical point dried and then lightly sputter coated with gold. This processing involves considerable specimen handling including several hours on a rotator during which the organ of Corti is at risk of being physically damaged. The following procedure uses low cost, readily available materials to hold the specimen during processing ,preventing physical damage while allowing an unhindered exchange of fluids.Following fixation, the cochlea is dehydrated to 70% ethanol then dissected under ethanol to prevent air drying. The holder is prepared by punching a hole in the flexible snap cap of a Wheaton vial with a paper hole punch. A small amount of two component epoxy putty is well mixed then pushed through the hole in the cap. The putty on the inner cap is formed into a “cup” to hold the specimen (Fig. 2), the putty on the outside is smoothed into a “button” to give good attachment even when the cap is flexed during handling (Fig. 3). The cap is submerged in the 70% ethanol, the bone at the base of the cochlea is seated into the cup and the sides of the cup squeezed with forceps to grip it (Fig.4). Several types of epoxy putty have been tried, most are either soluble in ethanol to some degree or do not set in ethanol. The only putty we find successful is “DUROtm MASTERMENDtm Epoxy Extra Strength Ribbon” (Loctite Corp., Cleveland, Ohio), this is a blue and yellow ribbon which is kneaded to form a green putty, it is available at many hardware stores.

scholarly journals Organ-specific, multimodal, wireless optoelectronics for high-throughput phenotyping of peripheral neural pathways

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Woo Seok Kim ◽  
Sungcheol Hong ◽  
Milenka Gamero ◽  
Vivekanand Jeevakumar ◽  
Clay M. Smithhart ◽  
...  
Keyword(s):  
High Throughput ◽  
Low Cost ◽  
Optoelectronic Device ◽  
Antenna System ◽  
Neural Pathways ◽  
Organ Specific ◽  
Coil Antenna ◽  
Sensory Fibers

AbstractThe vagus nerve supports diverse autonomic functions and behaviors important for health and survival. To understand how specific components of the vagus contribute to behaviors and long-term physiological effects, it is critical to modulate their activity with anatomical specificity in awake, freely behaving conditions using reliable methods. Here, we introduce an organ-specific scalable, multimodal, wireless optoelectronic device for precise and chronic optogenetic manipulations in vivo. When combined with an advanced, coil-antenna system and a multiplexing strategy for powering 8 individual homecages using a single RF transmitter, the proposed wireless telemetry enables low cost, high-throughput, and precise functional mapping of peripheral neural circuits, including long-term behavioral and physiological measurements. Deployment of these technologies reveals an unexpected role for stomach, non-stretch vagal sensory fibers in suppressing appetite and demonstrates the durability of the miniature wireless device inside harsh gastric conditions.

scholarly journals Optimizing the Reaction Conditions for the Formation of Fumarate via Trans-Hydrogenation

2021 ◽  
Author(s):  
Laura Wienands ◽  
Franziska Theiß ◽  
James Eills ◽  
Lorenz Rösler ◽  
Stephan Knecht ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Thermal Equilibrium ◽  
Reaction Rate ◽  
Low Cost ◽  
Hydrogen Gas ◽  
Metabolic Imaging ◽  
Reaction Conditions ◽  
Precursor Molecule ◽  
Solution Preparation

AbstractParahydrogen-induced polarization is a hyperpolarization method for enhancing nuclear magnetic resonance signals by chemical reactions/interactions involving the para spin isomer of hydrogen gas. This method has allowed for biomolecules to be hyperpolarized to such a level that they can be used for real time in vivo metabolic imaging. One particularly promising example is fumarate, which can be rapidly and efficiently hyperpolarized at low cost by hydrogenating an acetylene dicarboxylate precursor molecule using parahydrogen. The reaction is relatively slow compared to the timescale on which the hyperpolarization relaxes back to thermal equilibrium, and an undesirable 2nd hydrogenation step can convert the fumarate into succinate. To date, the hydrogenation chemistry has not been thoroughly investigated, so previous work has been inconsistent in the chosen reaction conditions in the search for ever-higher reaction rate and yield. In this work we investigate the solution preparation protocols and the reaction conditions on the rate and yield of fumarate formation. We report conditions to reproducibly yield over 100 mM fumarate on a short timescale, and discuss aspects of the protocol that hinder the formation of fumarate or lead to irreproducible results. We also provide experimental procedures and recommendations for performing reproducible kinetics experiments in which hydrogen gas is repeatedly bubbled into an aqueous solution, overcoming challenges related to the viscosity and surface tension of the water.

scholarly journals Genome-wide integration site detection using Cas9 enriched amplification-free long-range sequencing

2020 ◽  
Author(s):  
Joost van Haasteren ◽  
Altar M Munis ◽  
Deborah R Gill ◽  
Stephen C Hyde
Keyword(s):  
Long Range ◽  
Insertional Mutagenesis ◽  
Lentiviral Vector ◽  
Integration Site ◽  
Low Cost ◽  
Safety Evaluation ◽  
Read Length ◽  
Chromosomal Dna ◽  
Wide Range

Abstract The gene and cell therapy fields are advancing rapidly, with a potential to treat and cure a wide range of diseases, and lentivirus-based gene transfer agents are the vector of choice for many investigators. Early cases of insertional mutagenesis caused by gammaretroviral vectors highlighted that integration site (IS) analysis was a major safety and quality control checkpoint for lentiviral applications. The methods established to detect lentiviral integrations using next-generation sequencing (NGS) are limited by short read length, inadvertent PCR bias, low yield, or lengthy protocols. Here, we describe a new method to sequence IS using Amplification-free Integration Site sequencing (AFIS-Seq). AFIS-Seq is based on amplification-free, Cas9-mediated enrichment of high-molecular-weight chromosomal DNA suitable for long-range Nanopore MinION sequencing. This accessible and low-cost approach generates long reads enabling IS mapping with high certainty within a single day. We demonstrate proof-of-concept by mapping IS of lentiviral vectors in a variety of cell models and report up to 1600-fold enrichment of the signal. This method can be further extended to sequencing of Cas9-mediated integration of genes and to in vivo analysis of IS. AFIS-Seq uses long-read sequencing to facilitate safety evaluation of preclinical lentiviral vector gene therapies by providing IS analysis with improved confidence.

scholarly journals Hydroxyapatite-incorporation improves bone formation on endosseous PEEK implant in canine tibia

2020 ◽  
Vol 18 ◽  
pp. 228080002097517
Author(s):  
Yuan-ming Geng ◽  
Dong-ni Ren ◽  
Shu-yi Li ◽  
Zong-yi Li ◽  
Xiao-qing Shen ◽  
...  
Keyword(s):  
Bone Formation ◽  
Dental Implants ◽  
Low Cost ◽  
Low Elastic Modulus ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Alternative Material ◽  
Ct Analysis ◽  
Potential Alternative

Background: Poly Ether Ether Ketone (PEEK) has been considered as a potential alternative material for endosseous dental implants, for its low elastic modulus, biocompatibility, and low cost in customized device manufacture. Hydroxyapatite-incorporation is supposed to improve the poor osseointegration of PEEK. Methods: In the present study we analyzed the in vivo response of hydroxyapatite-incorporated PEEK (PEEK-HA) implants in canine tibia. PEEK-HA and PEEK implants were implanted and were examined 4 weeks and 12 weeks after implantation with radiology and histology. Commercial titanium dental implants served as controls. Results: The ratio of bone volume to tissue volume of PEEK-HA implants was higher than that of PEEK implants 4 weeks after implantation in the μ-CT analysis. The bone implant contact of PEEK and PEEK-HA implants showed no statistical difference in the histological examination, but newly-formed bone around PEEK-HA implants showed more signs of mineralization than that around PEEK implants. Conclusion: The study suggested that bone formation was improved with hydroxyapatite-incorporation in PEEK. Hydroxyapatite-incorporated PEEK implants may represent a potential material for endosseous dental implant.

scholarly journals Proanthocyanidins against Oxidative Stress: From Molecular Mechanisms to Clinical Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lingyu Yang ◽  
Dehai Xian ◽  
Xia Xiong ◽  
Rui Lai ◽  
Jing Song ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Low Cost ◽  
Natural Agents ◽  
Molecular Damage ◽  
And Control

Proanthocyanidins (PCs) are naturally occurring polyphenolic compounds abundant in many vegetables, plant skins (rind/bark), seeds, flowers, fruits, and nuts. Numerousin vitroandin vivostudies have demonstrated myriad effects potentially beneficial to human health, such as antioxidation, anti-inflammation, immunomodulation, DNA repair, and antitumor activity. Accumulation of prooxidants such as reactive oxygen species (ROS) exceeding cellular antioxidant capacity results in oxidative stress (OS), which can damage macromolecules (DNA, lipids, and proteins), organelles (membranes and mitochondria), and whole tissues. OS is implicated in the pathogenesis and exacerbation of many cardiovascular, neurodegenerative, dermatological, and metabolic diseases, both through direct molecular damage and secondary activation of stress-associated signaling pathways. PCs are promising natural agents to safely prevent acute damage and control chronic diseases at relatively low cost. In this review, we summarize the molecules and signaling pathways involved in OS and the corresponding therapeutic mechanisms of PCs.

Compact, low-cost Ti:Al_2O_3 laser for in vivo ultrahigh-resolution optical coherence tomography

2003 ◽  
Vol 28 (11) ◽  
pp. 905 ◽  
Author(s):  
A. Unterhuber ◽  
B. Považay ◽  
B. Hermann ◽  
H. Sattmann ◽  
W. Drexler ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Low Cost ◽  
Optical Coherence ◽  
Ultrahigh Resolution

Corrosion resistant metal-ceramic composite coatings for tribological applications

2021 ◽  
pp. 1-34
Author(s):  
Peter Renner ◽  
Swarn Jha ◽  
Yan Chen ◽  
Tariq Chagouri ◽  
Serge Kazadi ◽  
...  
Keyword(s):  
Ceramic Composite ◽  
Low Cost ◽  
Composite Coatings ◽  
Salt Spray ◽  
Extreme Environments ◽  
Safe Procedure ◽  
Corrosion Resistant ◽  
Wide Range ◽  
Metal Ceramic ◽  
Corrosion Resistant Coatings

Abstract Effective design of corrosion-resistant coatings is critical for the protection of metals and alloys. Many state-of-the-art corrosion-resistant coatings are unable to satisfy the challenges in extreme environments for tribological applications, such as elevated or cryogenic temperatures, high mechanical loads and impacts, severe wear, chemical attack, or a combination of these. The nature of challenging conditions demands that coatings have high corrosion and wear resistance, sustained friction control, and maintain surface integrity. In this research, multi-performance metal-ceramic composite coatings were developed for applications in harsh environments. These coatings were developed with an easy to fabricate, low-cost, and safe procedure. The coating consisted of boron nitride, graphite, silicon carbide, and transition metals such as chromium or nickel using epoxy as vehicle and bonding agent. Salt spray corrosion tests showed that 1010 carbon steel (1/4 hard temper) substrates lost 20-100× more mass than the coatings. The potentiodynamic polarization study showed better performance of the coatings by seven orders of magnitude in terms of corrosion relative to the substrate. Additionally, the corrosion rates of the coatings with Ni as an additive were five orders of magnitude lower than reported. The coefficient of friction of coatings was as low as 0.1, five to six times lower than that of epoxy and lower than a wide range of epoxy resin-based coatings found in literature. Coatings developed here exhibited potential in applications in challenging environments for tribological applications.

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