Study on the performance enhancement of biomedical implants: in vitro test under UV irradiation of titanium anodised in mixed electrolyte

Titanium (Ti) recently has widely been used in the biomedical applications due to its high performance. Therefore, surface modifications of titanium have attracted a lot of interest to provide better osseointegration. Ti was subjected to anodic oxidation process and in vitro testing to assess the bioactivity of titanium oxide (TiO2) coating. TiO2 coating has been anodised at room temperature in different electrolyte; in sulphuric acid (H2SO4); phosphoric acid (H3PO4); and a mixture of H2SO4 and H3PO4 acids. The parameters used in anodization were: concentration of the electrolytes, applied voltage and current density. The coated surface is then evaluated using different testing techniques; the microstructure using scanning electron microscope (SEM); the elemental analysis using Energy-dispersive x-ray spectroscopy (EDX); mineralogical and crystal structure using x-ray diffraction (XRD); absorption analysis using Fourier transform infrared spectroscopy (FT-IR); and the hydrophilicity using water contact angle (WCA). TiO2 was then subjected in vitro testing to assess the bioactivity of TiO2 surface; that is the apatite formation ability. The apatite formation of the TiO2 coating was precipitated by using simulated body fluid (SBF) in the dark and under the ultraviolet (UV) irradiation to mimic the reactions that may occur with the human bone-like cells layer. The testing was done to evaluate the apatite’s microstructure, mineralogy, elements and absorption. From the results it was found that higher apatite was obtained with the increased of the immersion time; higher apatite formation and crystallization was found at earlier time of immersion for the TiO2 that was immersed in SBF under the UV; higher apatite was obtained on the TiO2 coatings that were anodised in H2SO4, H3PO4 and mixture electrolyte at lower electrolyte concentration. The increased apatite on these coatings can be related to the strong Ti-O- functional groups on the coating surface. The highest apatite was obtained on the TiO2 coating that was anodised in a mixture electrolyte that has obtained Ti-OH functional group. The UV has resulted in the increased Ti-O- and Ti-OH groups, thus higher apatite precipitation ability

Analysis of mechanical properties and microstructure of multiple die cavity products produced in vertical and horizontal arrangement by gravity die casting

Multiple cavities die casting (Permanent die casting )in vertical arrangement and horizontal arrangement moulds are widely used in industry. However, manufacturers assume that each product produced in either arrangement would have the same quality. Manufacturers do not have enough information about the properties of each product, i.e. strength, internal defect and the microstructure. Furthermore, in actuality the quality of each product might be affected. It is the problem that we found within the market now (pinholes, cracks, misruns and etc. ), that is the reason investigation and comparison of the multi product in vertical and horizontal arrangement is needed. This investigation is needed to choose which arrangement is preferred to maintain the quality of the product. The methodology used are vickers microhardness test, izod test, ensile test, density and porosity test and optical microscope inspection for all produced sample. Results of this research show that castings produced at vertical arrangement mould have higher mechanical and properties than castings produced in horizontal arrangement mould. Vertical arrangement castings obtained higher density exceeds %1.6117 than horizontal arrangement castings that ranges between (1.156 and 4.8707 percent ). However, vertical arrangement castings obtained higher porosity exceeds %13.3885 than horizontal arrangement castings that ranges between (0.0809 and 7.4629 percent ). The hardness values for vertical castings ranges between (115HV and 78.9HV ), while ranges between (110HV and 79.1HV ) for horizontal castings. Castings in vertical arrangement hardness are %7.5442 higher than hardness for castings in horizontal arrangement. Impact strength values of vertical arrangement casting impact values that ranges between( 6J and 19J ) positions are %118.4615 higher than casting at horizontal arrangement casting positions that range between (2J and 11J ). Ultimate tensile strength for castings produced at vertical arrangement mould ranges between (122-182 MPa ) are %11.81 higher than castings produced at horizontal arrangement castings (101-178 MPa ). The microporosity at vertical arrangement positions are %35 lower than microporoity at horizontal arrangement positions

Effect of GTAW on the Tensile Strength and Hardness of Mild Steel

Gas tungsten metal arc welding (GTAW) is used to study the effect of the base metal thickness, welding current and welding speed on the tensile strength and hardness of mild steel welding. The analysis found that base metal thickness had the highest effect and highest means of tensile strength and hardness of the welding. Taguchi’s design (TD) suggested using higher base metal thickness, lower welding current and higher welding speed when welding mild steel in order to obtain maximum tensile strength and hardness. The welding that has higher tensile strength showed higher hardness. However, the hardness increased proportionally with the increased internal stresses of the welding. The welding showed wider heat affected zone (HAZ) with the increase in internal stresses of the welding

Fractional Supersymmetry As a Matrix Model

Using parafermionic field theoretical methods, the fundamentals of 2d fractional supersymmetry ${\bf Q}^{K} =P$ are set up. Known difficulties induced by methods based on the $U_{q}(sl(2))$ quantum group representations and non commutative geometry are overpassed in the parafermionic approach. Moreover we find that fractional supersymmetric algebras are naturally realized as matrix models. The K=3 case is studied in details. Links between 2d $({1\over 3},0)$ and $(({1\over 3}^{2}),0)$ fractional supersymmetries and N=2 U(1) and N=4 su(2) standard supersymmetries respectively are exhibited. Field theoretical models describing the self couplings of the matter multiplets $(0^{2},({1\over 3})^{2},({2\over 3})^{2})$ and $(0^{4},({1\over 3})^{4},({2\over 3})^{4})$ are given.Comment: Latex,no figure,17page

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Effect of GTAW on the Tensile Strength and Hardness of Mild Steel

Gas tungsten metal arc welding (GTAW) is used to study the effect of the base metal thickness, welding current and welding speed on the tensile strength and hardness of mild steel welding. The analysis found that base metal thickness had the highest effect and highest means of tensile strength and hardness of the welding. Taguchi’s design (TD) suggested using higher base metal thickness, lower welding current and higher welding speed when welding mild steel in order to obtain maximum tensile strength and hardness. The welding that has higher tensile strength showed higher hardness. However, the hardness increased proportionally with the increased internal stresses of the welding. The welding showed wider heat affected zone (HAZ) with the increase in internal stresses of the welding.</jats:p

In Vitro Apatite Deposition on TiO2 Film Derived from Electro-Chemical Treatment on Ti Substrate under Mixed Acid Electrolyte

Anodic oxidation is used to produce thick titania (TiO2) coating layer in a mixture of acids electrolyte to modify the TiO2 which is naturally formed on titanium (Ti) with a thickness of only a few nanometers and inert. The TiO2 coating is then subjected to an in-vitro test to evaluate their bioactivity in simulation body fluid (SBF). In the present work, oxide coatings of TiO2 were formed on Ti-Cp foil under potentials of 150 V at a current density of 100 mA/cm2 for 10 min. Multiple characterization techniques were used. X-ray diffraction (XRD) is used to obtain mineralogical phase, scanning electron microscope (SEM) is used to obtain surface morphology, water contact angle (WCA) is used to obtain the wettability of the TiO2, and the chemical absorption of the apatite precipitation was tested using Fourier transform infrared spectroscopy (FT-IR). From the testing results, surface morphology obtained an increased porosity with smaller pore size for TiO2, formed in mixed acids with higher molar concentration. Crystalline hydroxyapatite (HA) was obtained on all mixed solution coatings. Higher apatite precipitation and crystalline were obtained on the TiO2 coating with strong Ti-O- and Ti-OH functional groups, porous surface and strong anatase crystalline