TI6AL4V Surface Modification by Hydroxyapatite Powder Mixed Electric Discharge Machining for Medical Application

Titanium surface modification by the Hydroxyapatite (HA) mixed Electric Discharge Machining (EDM) is an alternative and promising technique to enhance the biocompatibility and to promote the biological performance in bone, which is dependent on surface properties, such as surface roughness, chemistry, and wettability. HA powder is used for the first time with electrical discharge machining to improve osteoblastic cell activity on the developed surfaces for TI6AL4V. Different HA concentrations in deionized water were tested as an experimental variable during EDM. Abrasive polishing and electrical discharge machined control surfaces without powder addition also analyzed to compare the results. The surface characteristics of analyzed samples were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffractometry (XRD), white light interferometry, and contact angle measurements. The wettability tests suggest that the hydroxyapatite powder mixed EDM’ed surfaces shows highly hydrophilic characteristics compared the other surfaces, abrasive polished and EDM’ed without powder addition in the dielectric. The results from the MTT assay revealed that those surfaces modified using HA powder addition in distilled water dielectric liquid promoted the most significant cell attachment/growth. The results indicate that HA powder mixed EDM offers a promising method for the surface modification of biomaterials such as titanium alloys

The effect of CoQ10 and vitamin E on serum total sialic acid, lipid-bound sialic acid, some trace elements and minerals in rats induced with doxorubicin

This study was designed to evaluate the effect of CoQ10 and vitamin E on serum total sialic acid (TSA), lipid bound sialic acid (LSA) and some elements in rat administered doxorubicin (DXR). Cu levels were increased in the group treated with DXR + vitamin E in comparison with DXR (p<0.05) and CoQ10 groups (p = 0.001). Furthermore, copper levels were increased in the group treated with DXR + CoQ10 in comparison with CoQ10 group (p < 0.05). Zn levels were decreased in the group treated with DXR + vitamin E in comparison with CoQ10 group (p < 0.05). Mg levels were decreased in subjects treated with DXR + vitamin E in comparison with the control group values (p < 0.05). Particularly, the observed increase in Cu levels in rats from DXR + vitamin E group might be due to the decrease of vitamin E. However, the oxidative damage could be as a result of DXR occurence and may be helpful to clinicians in chemotherapy using anthracycline.Key words: Doxorubicin, total sialic acid (TSA), lipid bound sialic acid (LSA), trace elements, minerals

Evaluation of the learning environment and the perceived weakness of the curriculum: student perspective

Background: Educational environment has been shown to have influence on learning outcome and affects student achievement, satisfaction, and success. The study was conducted to assess medical students’ perception of their learning environment and to explore areas of weakness within the educational environment.Methods: A mixed method of study, was performed using non-probability sampling at the Faculty of Medicine, Gezira University (FMUG), Sudan. An updated Arabic Dundee Ready Education Environment Measure (DREEM) was developed and administered to 854 students during the academic year 2016-2017.Results: Seventy five percent of students completed the inventory (638/854) and Sixty four percent (546/854) responded to the open-ended question providing comments and suggestions. The overall reliability coefficient alpha in this study was 0.914. The global score for this study was found positive (122/200). Students were most satisfied with the learning aspects, academic environment, and academic self-perception. However, they were unsatisfied with their teaching and social atmosphere (inadequate social support for stressed students, substandard teaching, overemphasised factual learning, unpleasant accommodation). The qualitative content analysis was performed and emerged with four themes: the physical environment, a number of students, pedagogical approaches and faculty-student communication.Conclusions: The study suggested the overall students’ perceptions of the educational environment in the FMUG were on the positive side. However, certain specific elements of the learning environment and educational programme need to be critically investigated and remedied. The updated Arabic DREAM can be used reliably in the context of medical education in Arabic speaking countries

Comparative kinetic modeling of growth and molecular hydrogen overproduction by engineered strains of \u3ci\u3eThermotoga maritima \u3c/i\u3e

Thermotoga maritima is an anaerobic hyperthermophilic bacterium known for its high amounts of hydrogen (H2) production. In the current study, the kinetic modeling was applied on the engineered strains of T. maritima that surpassed the natural H2 production limit. The study generated a kinetic model explaining H2 overproduction and predicted a continuous fermentation system. A Leudking-Piret equation-based model predicted that H2 production by Tma200 (0.217 mol-H2 g–1-biomass) and Tma100 (0.147 mol-H2 g–1-biomass) were higher than wild type (0.096 mol-H2 g–1 -biomass) with reduced rates of maltose utilization. Sensitivity analysis confirmed satisfactory fitting of the experimental data. The slow growth rates of Tma200 (0.550 h–1) and Tma100 (0.495 h–1) are compared with the wild type (0.663 h–1). A higher maintenance energy along with growth and non-growth H2 coefficients corroborate the higher H2 productivity of the engineered strains. The modeled data established a continuous fermentation system for the sustainable H2 production. (Inludes 2 supplemental figures

Comparative kinetic modeling of growth and molecular hydrogen overproduction by engineered strains of \u3ci\u3eThermotoga maritima \u3c/i\u3e

Thermotoga maritima is an anaerobic hyperthermophilic bacterium known for its high amounts of hydrogen (H2) production. In the current study, the kinetic modeling was applied on the engineered strains of T. maritima that surpassed the natural H2 production limit. The study generated a kinetic model explaining H2 overproduction and predicted a continuous fermentation system. A Leudking-Piret equation-based model predicted that H2 production by Tma200 (0.217 mol-H2 g–1-biomass) and Tma100 (0.147 mol-H2 g–1-biomass) were higher than wild type (0.096 mol-H2 g–1 -biomass) with reduced rates of maltose utilization. Sensitivity analysis confirmed satisfactory fitting of the experimental data. The slow growth rates of Tma200 (0.550 h–1) and Tma100 (0.495 h–1) are compared with the wild type (0.663 h–1). A higher maintenance energy along with growth and non-growth H2 coefficients corroborate the higher H2 productivity of the engineered strains. The modeled data established a continuous fermentation system for the sustainable H2 production. (Inludes 2 supplemental figures

TI6AL4V Surface Modification by Hydroxyapatite Powder Mixed Electric Discharge Machining for Medical Application

Titanium surface modification by the Hydroxyapatite (HA) mixed Electric Discharge Machining (EDM) is an alternative and promising technique to enhance the biocompatibility and to promote the biological performance in bone, which is dependent on surface properties, such as surface roughness, chemistry, and wettability. HA powder is used for the first time with electrical discharge machining to improve osteoblastic cell activity on the developed surfaces for TI6AL4V. Different HA concentrations in deionized water were tested as an experimental variable during EDM. Abrasive polishing and electrical discharge machined control surfaces without powder addition also analyzed to compare the results. The surface characteristics of analyzed samples were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffractometry (XRD), white light interferometry, and contact angle measurements. The wettability tests suggest that the hydroxyapatite powder mixed EDM’ed surfaces shows highly hydrophilic characteristics compared the other surfaces, abrasive polished and EDM’ed without powder addition in the dielectric. The results from the MTT assay revealed that those surfaces modified using HA powder addition in distilled water dielectric liquid promoted the most significant cell attachment/growth. The results indicate that HA powder mixed EDM offers a promising method for the surface modification of biomaterials such as titanium alloys

Powder Mixed Electrical Discharge Machining and Biocompatibility: A State of the Art Review

Electrical Discharge Machining (EDM) is a well-known process for machining of difficult to cut materials. Along with adding the powder in dielectric liquid, change in properties of machining gap results in a variety of sparks forms and lead different mechanisms under specific operational conditions during machining. The discharge models significantly differ from conventional EDM and leave its characteristics surface features. Primary studies of Powder Mixed Electrical Discharge Machining (PMEDM) focused on the understanding of material removal rate, surface quality, and tool wear rate concerning the widespread of the operational conditions evolved in the process. Then, the interactions with the powder material during discharging and the resultant surface properties impel the researcher's interest to achieve functional surfaces. In this respect, PMEDM is a significant concern in recent years as an alternative and simple production technique to obtain functional surfaces for specific needs. Nowadays, among the specific needs, production of biocompatible surfaces with the use of the technique provides a challenging opportunity to the researchers to address osseointegration issues. The study presents an introduction and review of the research work in PMEDM. The studies concerning machining efficiency, surface integrity, and generation of functional surfaces are presented and discussed in the light of current research trends. Attempts made to improve biocompatible surfaces with the use of the process also included to clarify the future trends in PMEDM

Ti6Al4V Surface Modification by Hydroxyapatite Powder Mixed Electrical Discharge Machining for Medical Application

Titanium surface modification by the Hydroxyapatite (HA) mixed Electrical Discharge Machining (EDM) is an alternative and promising technique to enhance the biocompatibility and to promote the biological performance in bone, which is dependent on surface properties, such as surface roughness, chemistry, and wettability. HA powder is used for the first time with electrical discharge machining to improve osteoblastic cell activity on the developed surfacesforTI6AL4V. Different HA concentrations in deionized water were tested as an experimental variable during EDM. Abrasive polishing and electrical discharge machined control surfaces without powder addition also analyzed to compare the results. The surface characteristics of analyzed samples were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffractometry (XRD), white light interferometry, and contact angle measurements. The wettability tests suggest that the hydroxyapatite powder mixed EDM’ed surfaces shows highly hydrophilic characteristics compared the other surfaces, abrasive polished and EDM’ed without powder addition in the dielectric. The results from the MTT assay revealed that those surfaces modified using HA powder addition in distilled water dielectric liquid promoted the most significant cell attachment/growth. The results indicate that HA powder mixed EDM offers a promising method for the surface modification of biomaterials such as titanium alloys

Dynamics investigation on motorcycle chassis based on Finite Element (FE) modelling and updating

Motorcycles built from multiple materials such as steel and aluminium that formed a welded of beams to construct the chassis. The frame is designed by combining the part-by-part saddle, handlebar and wheel that are attached together. In this study, the identification of structural dynamics study for motorcycle chassis was conducted to identify modal properties such as natural frequencies and mode shapes. This could be achieved by using two different analysis approaches; Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA). For FEA analysis, 3D modeling of the chassis frame is needed and modelled using CAD software. Normal mode analysis was run on modelled structure to determine modal properties after meshing type and properties of materials declared. Impact hammer testing using roving accelerometer method was conducted for EMA study and comparison of modal properties with FEA is carried out. Discrepancies that appeared after correlation among two approaches attempted to be reduced by performing model updating procedure and it was successfully reduced the average percentage of error to be less than 10%. The results show that the model updating was an effective technique for improving the discrepancy that may exist due to modelling issue and material properties prediction in FEA. This study clearly shows that model updating technique is an effective way of reducing the discrepancies between EMA and FEA

Determination of resilience factors in individuals who tested COVID-19 positive

The main purpose of this study was to determine the protective factors that can aid people in their recovery or help maintain their well-being in the face of collective adversity, in this case, the COVID-19 pandemic, and to examine how these factors can be further strengthened. The study included 89 participants from 14 different cities in Turkey, ranging in age from 18 to 70, 46 of them men and 43 women. In light of the findings of the study, it can be said that psychosocial support and re-adaptation programmes are needed to ease the social-emotional burden of living through a pandemic on individuals (especially those who survived the virus) even after the COVID-19 pandemic ends