Biomimetic bone-like apatite coating on anodised titanium in simulated body fluid under UV irradiation

Low temperature deposition techniques of bioceramics coatings are now being researched and developed to avoid deficiencies inherent in high temperature techniques. Biomimetic coatings are a solution-based method conducted at ambient temperature to deposit bioactive coatings on the surface. The current study aims to investigate the effect of ultraviolet (UV) irradiation on the coating of bone-like apatite on the anodised surface. High purity titanium foils were anodised with an applied voltage of 350 V, current density of 70 mA.cm-2 in mixture of 0.04 M β-glycerophosphate disodium salt pentahydrate (β-GP) and 0.4 M calcium acetate (CA) for 10 min. After anodic oxidation, UV light treatment was conducted in pH-adjusted distilled water for 12 h with ultraviolet light A (UVA) irradiation. Subsequently, the UV-treated anodised titanium foils were soaked in SBF for 7 days with/without UVA irradiation. After SBF immersion for 7 days, anodised titanium with combination of UV light treatment and UV irradiation during in vitro testing was fully covered by highly crystalline bone-like apatite at maximal thickness of 2.8 μm. This occurred mainly due to the formation of large amounts of Ti-OH groups which act as nucleation sites for bone-like apatite. This study also revealed that UV irradiation during in vitro testing is superior in promoting growth of bone-like apatite compared to UV light treatment. The suggested mechanism for bone-like apatite formation on anodised titanium under different UV irradiation conditions is illustrated in this article. The findings of this study indicated that biomimetic bone-like apatite coating with assistance of UV irradiation is an effective method in accelerating the formation of bone-like apatite

Characterizations on microencapsulated sunflower oil as self-healing agent using In situ polymerization method

This paper emphasizes the characterization on the microencapsulation of sunflower oil as self-healing agent. In-situ polymerization method mainly implicates in the microencapsulation process. The analysis of microencapsulated sunflower oil via prominent characterization of yield of microcapsules, microcapsules characteristics and Fourier Transmission Infa-Red Spectroscopy (FTIR). The prime optimization used was reaction time of microencapsulation process in the ranges of 2, 3 and 4 h. The higher reaction time of microencapsulation process resulted in a higher yield of microcapsules. The yield of microcapsules increases from 46 to 53% respectively by the increasing of reaction time from 2 to 4 h. The surface morphology study associating the diameter of microcapsules measured to analyse the prepared microcapsules. It was indicated that microcapsules were round in shape with smooth micro-surfaces. It was discovered that the diameter of microcapsules during microencapsulation process after 4 h reaction time was in average of 70.53 μm. This size was measured before filtering the microcapsules with solvent and dried in vacuum oven. Apparently, after filtering and drying stage, the diameter of microcapsules specifically identified under Field Emission Scanning Electron Microscopy (FESEM) showing the size of 2.33 μm may be due to the removing the suspended oil surrounded the microcapsules. Sunflower oil as core content and urea formaldehyde (UF) as shell of microcapsules demonstrated the proven chemical properties on characterization by FTIR with the stretching peak of 1537.99 - 1538.90 cm-1 (-H in -CH2), 1235.49 - 1238.77 cm-1 (C-O-C Vibrations at Ester) and 1017.65 - 1034.11 cm-1 (C-OH Stretching Vibrations). It was showed that sunflower oil can be considered as an alternative nature resource for self-healing agent in microencapsulation process. The characterization of microencapsulated sunflower oil using in-situ polymerization method showed that sunflower oil was viable self-healing agent to be encapsulated and incorporated in metal coating

Calorons, Nahm's equations on S^1 and bundles over P^1xP^1

The moduli space of solutions to Nahm's equations of rank (k,k+j) on the circle, and hence, of SU(2) calorons of charge (k,j), is shown to be equivalent to the moduli of holomorphic rank 2 bundles on P^1xP^1 trivialized at infinity with c_2=k and equipped with a flag of degree j along P^1x{0}. An explicit matrix description of these spaces is given by a monad constructio

Extraction of biological hydroxyapatite from bovine bone for biomedical applications

Current biomedical field demands intensive research on cost-effective and high availability materials to fulfil its various applications. Owing to its similar characteristic to human bone, biological hydroxyapatite (HAp) has been used as an alternative in bone replacement and implantation. In this study, biological HAp was extracted from bovine bones via calcination. Powders calcined at 700 °C and 900 °C showed the presence of HAp. The field emission scanning electron microscope (FESEM) analysis shows that the irregular morphology emerged and the size was increasing as the calcination temperature increased. By increasing the temperature of 1100 °C, β-TCP (beta-tricalcium phosphate) started to develop and influenced the ratio of Ca/P. At 900 °C, the Ca/P ratio obtained was 1.70, and closest to the theoretical ratio of Ca/P. The presence of trace elements like Ca, Mg, Sr Na, K and Zn in all samples are proved via energy-dispersive X-ray spectroscopy (EDS) analysis, and these elements help to enhance the bioactivity hence make it a good alternative in biomedical applications

Preparation of PtNi Nanoparticles for the Electrocatalytic Oxidation of Methanol

Carbon supported PtNi nanoparticles were prepared by hydrazine reduction of Pt and Ni precursor salts under different conditions, namely by conventional heating (PtNi-1), by prolonged reaction at room temperature (PtNi-2) and by microwave assisted reduction (PtNi-3). The nanocomposites were characterized by XRD, EDX, XPS and TEM and used as electrocatalysts in direct methanol fuel cell (DMFC) reactions. Investigations into the mechanism of PtNi nanoparticle formation revealed that platinum nanoparticle seeding was essential for the formation of the bimetallic nanoparticles. The average particle size of PtNi prepared by microwave irradiation was the lowest, in the range of 2.9 – 5.8 nm. The relative rates of electrooxidation of methanol at room temperature as measured by cyclic voltammetry showed an inverse relationship between catalytic activity and particle size in the following order PtNi-1 < PtNi-2 < PtNi-3.Singapore-MIT Alliance (SMA

Athletic Success and Donation Intentions: Does Sense of Community Mediate?

As Division-I FBS expenditures continue to rise, it is of paramount importance for universities to better understand the benefits received as a result of athletic success. Specifically, previous research has identified a strengthened campus sense of community and increased donation levels as potential beneficial outcomes of football success. However, it is not clear how football success, sense of community, and donation intention operate cumulatively. Therefore, this study sought to explain the effect of football success on donation intentions, with the mediating effect of campus sense of community. FBS students (N = 253) reported their perceptions of football success, campus sense of community, and intentions to donate to their universities’ annual funds, as well as the athletic departments. Two separate mediation analyses indicated partial mediation for both annual fund donation intentions and athletic department donation intentions. Team identification was also found to be a positive, significant predictor of sense of community, (p &lt; .05). These results suggest university administrators may anticipate institution-wide benefits from football success, but they may be contingent upon students’ identification levels with the football team

Athletic Success and Donation Intentions: Does Sense of Community Mediate?

As Division-I FBS expenditures continue to rise, it is of paramount importance for universities to better understand the benefits received as a result of athletic success. Specifically, previous research has identified a strengthened campus sense of community and increased donation levels as potential beneficial outcomes of football success. However, it is not clear how football success, sense of community, and donation intention operate cumulatively. Therefore, this study sought to explain the effect of football success on donation intentions, with the mediating effect of campus sense of community. FBS students (N = 253) reported their perceptions of football success, campus sense of community, and intentions to donate to their universities’ annual funds, as well as the athletic departments. Two separate mediation analyses indicated partial mediation for both annual fund donation intentions and athletic department donation intentions. Team identification was also found to be a positive, significant predictor of sense of community, (p &lt; .05). These results suggest university administrators may anticipate institution-wide benefits from football success, but they may be contingent upon students’ identification levels with the football team

Economic Integration and Structure Change in Stock Market Dependence: Empirical Evidences of CEPA

[[abstract]]This study investigates dependence structure changes between the Hong Kong and Chinese stock markets as a result of the Closer Economic Partnership Arrangement (CEPA). Four copulas, Gaussian, student t, Gumbel, and Clayton are used to search for unknown dependence structure changes. This study presents two main findings. First, the dependence between the Hong Kong and Chinese stock markets increased significantly following the structure change that occurred on February2, 2005, about one year after CEPA took effect. Second, the distribution of dependence structure altered from Gumbel copula before the structure change to t copula after the structure change. CEPA’s effects not only changed the dependence parameters but also changed the dependence structure’s distribution.[[notice]]補正完畢[[booktype]]紙本[[booktype]]電子

Single Stranded DNA Induced Assembly of Gold Nanoparticles

The binding affinity of single stranded DNA (ssDNA) for gold nanoparticle surface is studied in this work. The data indicate that the strength of interaction between ssDNA and Au particle surface is closely related to the particle size, with smaller particles (5 nm) producing the most pronounced effects. From these experimental findings, a single stranded DNA (ssDNA) based method to assimilate 13 and 5 nm gold nanoparticles was developed, and verified by transmission electron microscopy (TEM).Singapore-MIT Alliance (SMA

SU(2) Calorons and Magnetic Monopoles

We investigate the self-dual Yang-Mills gauge configurations on $R^3\times S^1$ when the gauge symmetry SU(2) is broken to U(1) by the Wilson loop. We construct the explicit field configuration for a single instanton by the Nahm method and show that an instanton is composed of two self-dual monopoles of opposite magnetic charge. We normalize the moduli space metric of an instanton and study various limits of the field configuration and its moduli space metric.Comment: 17 pages, RevTex, 1 Figur