Generation of Micro Texture Including Calcium and Phosphorus Elements on Titanium Alloy for Improvement of Biocompatibility With Laser Induced Mist Surface Treatment

2020 ◽  
Author(s):  
Atsushi Ezura ◽  
Kazutoshi Katahira ◽  
Jun Komotori
Keyword(s):  
Aqueous Solution ◽  
Titanium Alloy ◽  
Titanium Alloys ◽  
P Element ◽  
Hard Tissue ◽  
Osteoblast Cells ◽  
P Elements ◽  
Test Pieces ◽  
Calcium And Phosphorus ◽  
Contact Part

Abstract Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility for reduce adhesion period. For improvement of biocompatibility of titanium alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V-ELI alloys surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of specimens and the treatment was stable. In order to estimate biocompatibility of treated surfaces having micro texture with Ca and P element, culture assays using osteoblast cells were conducted. As result, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than treated specimen soaked in glycerophosphoric acid calcium aqueous solution.

scholarly journals Generation of Biocompatible Titanium Alloy Surfaces Including Calcium and Phosphorus Elements by Laser-Induced Mist Spraying Wet Treatment

2020 ◽  
Vol 14 (4) ◽  
pp. 575-581
Author(s):  
Atsushi Ezura ◽  
Kazutoshi Katahira ◽  
Jun Komotori ◽  
◽  
◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Laser Irradiation ◽  
Hard Tissue ◽  
Complicated Shape ◽  
Osteoblast Cells ◽  
Cell Compatibility ◽  
P Elements ◽  
Test Pieces ◽  
Modified Surface ◽  
Contact Part

Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility to reduce adhesion period. For improvement of biocompatibility of Ti-6Al-4V ELI alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, micro texture was generated on the Ti-6Al-4V ELI alloy surfaces utilizing laser irradiation, in order to improve biocompatibility. The biocompatibility was evaluated by osteoblast cell culture assays. The results indicated the surface having micro texture improve biocompatibility as compared with untreated surface. This was considered in order the fact that the formed modified surface had hydrophilicity, thereby improving the cell compatibility, and the cell adhesion due to the complicated shape. In addition, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V ELI alloy surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution was applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of test pieces and the treatment was stable. In order to estimate biocompatibility, culture assays using osteoblast cells were conducted on the treated surface having micro texture including Ca and P elements. As results, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than either untreated specimen or treated specimen soaked in glycerophosphoric acid calcium aqueous solution.

Enhancement of Mechanical Biocompatibility of Titanium Alloys by Deformation-Induced Transformation

2016 ◽  
Vol 879 ◽  
pp. 125-130
Author(s):  
Mitsuo Niinomi
Keyword(s):  
Fracture Toughness ◽  
Titanium Alloy ◽  
Phase Transformation ◽  
Titanium Alloys ◽  
Biomedical Applications ◽  
Hard Tissue ◽  
Β Phase ◽  
Ω Phase ◽  
Increased Strength ◽  
Strength And Ductility

Metastable β-type titanium alloys are highly suitable for use as structural biomaterials applied to hard tissue, i.e., as cortical bone (hereafter, bone) replacing implants. However, their mechanical biocompatibitities, such as the Young’s modulus, strength and ductility balance, fatigue strength, resistance against fatigue crack propagation and fracture toughness, require improvenent for increased compatibility with bone. Through deformation, the metastable β-phase in a metastable β-type titanium alloy is transformed into various phases, such as α’ martensite, α” martensite, and ω-phases with exact phase depending by metastable β-phase stability. In addition, twinning is also induced by deformation. Deformation twinning effectively enhances the work hardening in the metastable β-type titanium alloy, leading to increased strength and ductility. This improvement is accompanied by with other deformation-induced transformations including the appearance of deformation-induced martensite and ω-phase transformation. The enhancement of the mechanical biocompatibility of various materials using the abovementioned deformation-induced transformation is described in this paper, for both newly developed metastable β-type Ti-Mo and Ti-Cr alloys for biomedical applications.

scholarly journals A hobo Transgene That Encodes the P-Element Transposase in Drosophila melanogaster: Autoregulation and Cytotype Control of Transposase Activity

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 195-204 ◽  
Author(s):  
Michael J Simmons ◽  
Kevin J Haley ◽  
Craig D Grimes ◽  
John D Raymond ◽  
Jarad B Niemi
Keyword(s):  
Drosophila Melanogaster ◽  
Gonadal Dysgenesis ◽  
P Element ◽  
Hsp70 Gene ◽  
Alternate Splicing ◽  
Male And Female ◽  
P Elements ◽  
Male Germline ◽  
Female Germline ◽  
Transposase Expression

Abstract Drosophila were genetically transformed with a hobo transgene that contains a terminally truncated but otherwise complete P element fused to the promoter from the Drosophila hsp70 gene. Insertions of this H(hsp/CP) transgene on either of the major autosomes produced the P transposase in both the male and female germlines, but not in the soma. Heat-shock treatments significantly increased transposase activity in the female germline; in the male germline, these treatments had little effect. The transposase activity of two insertions of the H(hsp/CP) transgene was not significantly greater than their separate activities, and one insertion of this transgene reduced the transposase activity of P(ry+, Δ2-3)99B, a stable P transgene, in the germline as well as in the soma. These observations suggest that, through alternate splicing, the H(hsp/CP) transgene produces a repressor that feeds back negatively to regulate transposase expression or function in both the somatic and germline tissues. The H(hsp/CP) transgenes are able to induce gonadal dysgenesis when the transposase they encode has P-element targets to attack. However, this ability and the ability to induce P-element excisions are repressed by the P cytotype, a chromosomal/cytoplasmic state that regulates P elements in the germline.

scholarly journals The Regulatory Properties of Autonomous Subtelomeric P Elements Are Sensitive to a Suppressor of variegation in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Natural Populations ◽  
P Element ◽  
Single Element ◽  
Heterochromatin Protein 1 ◽  
X Chromosomes ◽  
P Elements ◽  
Associated Sequences ◽  
Regulatory Properties

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.

scholarly journals hobo enhancer trapping mutagenesis in Drosophila reveals an insertion specificity different from P elements.

Genetics ◽  
1993 ◽  
Vol 135 (4) ◽  
pp. 1063-1076 ◽  
Author(s):  
D Smith ◽  
J Wohlgemuth ◽  
B R Calvi ◽  
I Franklin ◽  
W M Gelbart
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Enhancer Trap ◽  
P Element ◽  
Present Evidence ◽  
P Elements ◽  
Element Insertion ◽  
Enhancer Trapping ◽  
Indispensable Tool

Abstract P element enhancer trapping has become an indispensable tool in the analysis of the Drosophila melanogaster genome. However, there is great variation in the mutability of loci by these elements such that some loci are relatively refractory to insertion. We have developed the hobo transposable element for use in enhancer trapping and we describe the results of a hobo enhancer trap screen. In addition, we present evidence that a hobo enhancer trap element has a pattern of insertion into the genome that is different from the distribution of P elements in the available database. Hence, hobo insertion may facilitate access to genes resistant to P element insertion.

Study of the Key Issues of Friction Stir Welding of Titanium Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu
Keyword(s):  
Titanium Alloy ◽  
Friction Stir Welding ◽  
Melting Point ◽  
Titanium Alloys ◽  
Welding Process ◽  
High Strength ◽  
Liquid Cooling ◽  
Friction Stir ◽  
Key Issues ◽  
Aluminum And Magnesium Alloys

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.

scholarly journals A novel repressor of P element transposition in Drosophila melanogaster

1998 ◽  
Vol 71 (1) ◽  
pp. 21-30 ◽  
Author(s):  
RICHARD M. BADGE ◽  
JOHN F. Y. BROOKFIELD
Keyword(s):  
Drosophila Melanogaster ◽  
Inbred Line ◽  
Gonadal Dysgenesis ◽  
Full Length ◽  
P Element ◽  
Temperature Dependent ◽  
P Elements

We have discovered, in an inbred line (Loua) of Drosophila melanogaster from Zaïre, a third chromosome showing unusual P element repression. Repression of P element transposition by this chromosome, named Loua3, is dominant zygotic and has three unusual properties. Firstly, its repression of the gonadal dysgenesis caused by a strong P haplotype is strongly temperature-dependent, being most evident at higher rearing temperatures. Secondly, subdivision of Loua3 by recombination abolishes repression: the effect is apparently a function of the intact chromosome. Finally, Loua3 also diminishes somatic lethality when chromosomes carrying many ‘ammunition’ elements (Birmingham2) are exposed to the constitutive transposase source Δ2-3(99B). The chromosome has 17 P elements, none full-length, located in at least 12 dispersed positions.

scholarly journals Experimental Study of tool Wear Mechanisms in Conventional and High Pressure Coolant Assisted Machining of Titanium Alloy Ti17

2013 ◽  
Vol 554-557 ◽  
pp. 1961-1966 ◽  
Author(s):  
Yessine Ayed ◽  
Guenael Germain ◽  
Amine Ammar ◽  
Benoit Furet
Keyword(s):  
High Pressure ◽  
Titanium Alloy ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Tool Life ◽  
Wear Mechanisms ◽  
Cutting Forces ◽  
Cutting Edge ◽  
Rake Face ◽  
High Pressure Coolant

Titanium alloys are known for their excellent mechanical properties, especially at high temperature. But this specificity of titanium alloys can cause high cutting forces as well as a significant release of heat that may entail a rapid wear of the cutting tool. To cope with these problems, research has been taken in several directions. One of these is the development of assistances for machining. In this study, we investigate the high pressure coolant assisted machining of titanium alloy Ti17. High pressure coolant consists of projecting a jet of water between the rake face of the tool and the chip. The efficiency of the process depends on the choice of the operating parameters of machining and the parameters of the water jet such as its pressure and its diameter. The use of this type of assistance improves chip breaking and increases tool life. Indeed, the machining of titanium alloys is generally accompanied by rapid wear of cutting tools, especially in rough machining. The work done focuses on the wear of uncoated tungsten carbide tools during machining of Ti17. Rough and finish machining in conventional and in high pressure coolant assistance conditions were tested. Different techniques were used in order to explain the mechanisms of wear. These tests are accompanied by measurement of cutting forces, surface roughness and tool wear. The Energy-dispersive X-ray spectroscopy (EDS) analysis technique made it possible to draw the distribution maps of alloying elements on the tool rake face. An area of material deposition on the rake face, characterized by a high concentration of titanium, was noticed. The width of this area and the concentration of titanium decreases in proportion with the increasing pressure of the coolant. The study showed that the wear mechanisms with and without high pressure coolant assistance are different. In fact, in the condition of conventional machining, temperature in the cutting zone becomes very high and, with lack of lubrication, the cutting edge deforms plastically and eventually collapses quickly. By contrast, in high pressure coolant assisted machining, this problem disappears and flank wear (VB) is stabilized at high pressure. The sudden rupture of the cutting edge observed under these conditions is due to the propagation of a notch and to the crater wear that appears at high pressure. Moreover, in rough condition, high pressure assistance made it possible to increase tool life by up to 400%.

Preparation of Titanium Alloy Parts by Powder Compact Extrusion of a Powder Mixture and Scaled up Manufacture

2016 ◽  
Vol 704 ◽  
pp. 75-84 ◽  
Author(s):  
Fei Yang ◽  
Brian Gabbitas ◽  
Ajit Pal Singh ◽  
Stella Raynova ◽  
Hui Yang Lu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Powder Metallurgy ◽  
Titanium Alloys ◽  
Powder Mixture ◽  
Powder Compact ◽  
Blended Elemental ◽  
Pilot Plant Scale ◽  
Near Net Shape ◽  
Titanium Processing ◽  
The University

Blended Elemental Powder Metallurgy (BE-PM) is a very attractive method for producing titanium alloys, which can be near-net shape formed with compositional freedom. However, a minimization of oxygen pick-up during processing into manufactured parts is a big challenge for powder metallurgy of titanium alloys. In this paper, different approaches for preparing titanium alloy parts by powder compact extrusion with 0.05-0.1wt.% of oxygen pick-up during manufacturing are discussed. The starting materials were a powder mixture of HDH titanium powder, other elemental powders and a master alloy powder. Different titanium alloys and composites, such as Ti-6Al-4V, Ti-4Al-4Sn-4Mo-0.5Si, Ti-5Al-5V-5Mo-3Cr, and Ti-5Al-5V-5Mo-3Cr-5vol%TiB, with different profiles such as round and rectangular bars, a wedge profile, wire and tubes have been successfully manufactured on a laboratory and pilot-plant scale. Furthermore, a possible route for scaling up the titanium processing capabilities in the University of Waikato has also been discussed.

The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 752-762 ◽  
Author(s):  
Alireza Sameny ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Critical Role ◽  
Mutagenic Effect ◽  
P Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
P Elements ◽  
Single Well ◽  
Dose Dependent

Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.

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