Investigating the Roles of Protein on the Cobalt Alloy Surface Degradation for Biomedical Implant Through Tribocorrosion Mechanisms

Previous investigation has established the formation of tribofilm is influenced by tribochemical reactions between the electrolyte and the articulating surface of cobalt alloy through sliding tests in various simulated fluids. Although it has successfully characterized the film composition via spectroscopy analysis and indicated to have impact on material loss, a comprehensive understanding of the material degradation mechanism in tribocorrosion condition was still lacking. Therefore, this study aims to investigate the role of protein in the tribocorrosive degradation of cobalt-chromium-molybdenum (CoCrMo) alloy in different simulated physiological electrolytes. Using a similar testing protocol, tribocorrosion tests were conducted with reciprocating ceramic ball against CoCrMo samples immersed in saline and culture medium, compared to both electrolytes diluted with 25% fetal bovine serum (FBS). Synergistic and mechanistic approaches were employed to model the tribocorrosive degradation. Results reveal that protein plays a beneficial role in reducing corrosive (electrochemical) surface degradation under tribocorrosion condition, whilst increasing mechanical wear degradation in the process. Despite studies have shown that tribocorrosion behavior in metal alloys is highly influenced by the presence of organic matter, this study provides a more clarity of the roles played by protein in tribocorrosive degradation on CoCrMo surface as its novel finding

The Effect of Protein Structure and Concentration on Tribocorrosion and Film Formation on CoCrMo Alloys

The formation of tribochemical reaction layers, better known as tribofilms, on cobalt-chromium-molybdenum (CoCrMo) alloys commonly used in orthopaedic applications has been hypothesized to reduce degradation owing to wear and corrosion. However, the mechanisms and pathways influencing tribofilm formation remain largely unknown. This study aims to develop a clearer understanding of the role of protein structures and its concentration on tribocorrosion and surface tribofilms formed on CoCrMo alloys during boundary regime sliding. A reciprocating tribometer with a three-electrode electrochemical cell was employed to simulate and monitor the tribocorrosion of CoCrMo in situ. As-received Foetal Bovine Serum (as-FBS) and pre-heated FBS at 70 °C for 1 h (de-FBS) were diluted with saline (0.9% NaCl) at different concentrations (25% and 75% v/v) and utilized as electrolytes during the tribocorrosion tests. The result shows that the denatured protein structure in electrolyte tends to reduce the volume losses due to wear and corrosion on the CoCrMo samples with an appreciation of the protein tribofilms. On the other hand, an increased protein concentration increased the total volume loss due to corrosive processes. A novel finding revealed in this study is that the tribocorrosion mechanism of the CoCrMo surface is dependent on the protein structure, concentration and sliding duration due to the change in surface condition.</p

PEMBUATAN GAME EDUKASI PETUALANGAN SI GEMUL SEBAGAI PEMBELAJARAN PENGENALAN DAERAH SOLO RAYA PADA ANAK

Perkembangan administrasi setelah Orde Baru pemerintah telah menghapus tingkat Karesidenan di Indonesia termasuk Karesidenan Surakarta. Akibatnya nama Karesidenan Surakarta berubah menjadi Eks-Karesidenan Surakarta atau Wilayah Solo Raya. Wilayah Solo Raya terdiri dari tujuh Kabupaten tiga di antaranya berbatasan langsung dengan kota Solo yaitu Boyolali, Sukoharjo dan Karanganyar. Tiga yang lain tidak berbatasan langsung yaitu Wonogiri, Sragen dan Klaten. Masing-masing daerah memiliki slogan, tempat wisata dan makanan khas yang berbeda, namun masih banyak masyarakat yang kurang mengenalnya. Hasil observasi menunjukkan bahwa kebanyakan anak-anak usia sekolah dasar belum mengetahui daerah-daerah mana saja yang masuk dalam daerah Solo Raya. Saat ini teknologi semakin berkembang secara pesat dan penggunaan gadget dapat difungsikan sebagai media edukasi. Dalam penelitian ini telah dikembangkan Game Edukasi berjudul Petualangan Gembul untuk mengenal daerah di Solo Raya Berbasis Android. Metode yang digunakan dalam pengembagan game ini adalah Software Development Life Cycle (SDLC) Water Fall dimulai dari analisis, perancangan, pembuatan, pengujian dan pemeliharaan. Model permainan yang disajikan level pertama berupa adventure yang dilengkapi latar belakang daerah khas masing-masing, level kedua berupa kuis tanya jawab dan level ketiga berupa game puzzel yang berisi foto khas daerah untuk ditata ulang. Pengujian yang dilakukan meliputi pengujian perangkat terhadap 3 perangkat android yang berbeda spesifikasinya dan pengujian hasil pembuatan game melalui kuisioner dalam aspek penyampaian informasi dan desain visual game. Hasil penelitian menyebutkan bahwa 75% game tersebut memudahkan dalam mengenal daerah Solo Raya dan 79% menyebutkan bahwa tampilan game tersebut menarik. Kata kunci: game, android, anak, solo raya

The Effect of Protein Structure and Concentration on Tribocorrosion and Film Formation on CoCrMo Alloys

The formation of tribochemical reaction layers, better known as tribofilms, on cobalt-chromium-molybdenum (CoCrMo) alloys commonly used in orthopaedic applications has been hypothesized to reduce degradation owing to wear and corrosion. However, the mechanisms and pathways influencing tribofilm formation remain largely unknown. This study aims to develop a clearer understanding of the role of protein structures and its concentration on tribocorrosion and surface tribofilms formed on CoCrMo alloys during boundary regime sliding. A reciprocating tribometer with a three-electrode electrochemical cell was employed to simulate and monitor the tribocorrosion of CoCrMo in situ. As-received Foetal Bovine Serum (as-FBS) and pre-heated FBS at 70 °C for 1 h (de-FBS) were diluted with saline (0.9% NaCl) at different concentrations (25% and 75% v/v) and utilized as electrolytes during the tribocorrosion tests. The result shows that the denatured protein structure in electrolyte tends to reduce the volume losses due to wear and corrosion on the CoCrMo samples with an appreciation of the protein tribofilms. On the other hand, an increased protein concentration increased the total volume loss due to corrosive processes. A novel finding revealed in this study is that the tribocorrosion mechanism of the CoCrMo surface is dependent on the protein structure, concentration and sliding duration due to the change in surface condition

Kinetic Studies of Cs+ and Sr2+ Ion Exchange Using Clinoptilolite in Static Columns and an Agitated Tubular Reactor (ATR)

Natural clinoptilolite was studied to assess its performance in removing caesium and strontium ions, using both static columns and an agitated tube reactor (ATR) for process intensification. Kinetic breakthrough curves were fitted using the Thomas and Modified Dose Response (MDR) models. In the static columns, the clinoptilolite adsorption capacity (qe) for 200 ppm ion concentrations was found to be ~171 and 16 mg/g for caesium and strontium, respectively, highlighting the poor material ability to exchange strontium. Reducing the concentration of strontium to 100 ppm, however, led to a higher strontium qe of ~48 mg/g (close to the maximum adsorption capacity). Conversely, halving the column residence time to 15 min decreased the qe for 100 ppm strontium solutions to 13–14 mg/g. All the kinetic breakthrough data correlated well with the maximum adsorption capacities found in previous batch studies, where, in particular, the influence of concentration on the slow uptake kinetics of strontium was evidenced. For the ATR studies, two column lengths were investigated (of 25 and 34 cm) with the clinoptilolite embedded directly into the agitator bar. The 34 cm-length system significantly outperformed the static vertical columns, where the adsorption capacity and breakthrough time were enhanced by ~30%, which was assumed to be due to the heightened kinetics from shear mixing. Critically, the increase in performance was achieved with a relative process flow rate over twice that of the static columns

PENINGKATAN LITERASI TEKNOLOGI AUGMENTED REALITY UNTUK PEMBELAJARAN DENGAN AR HALOKIDS BERBASIS GAMES

Implementasi teknologi AR (Augmented Reality) sebagai media bantu dalam pembelajaran sudah banyak digunakan di bidang pendidikan salah satunya dalam pendidikan anak usia dini (PAUD). Pengimplementasian Augmented Reality dalam bentuk game edukasi dapat menjadi media pembelajaran yang interaktif dan menarik bagi siswa PAUD. Tetapi sebagian besar pengajar PAUD di TK Adz Dzikru, Kabupaten Karanganyar masih belum memanfaatkan media ini dan masih mengutamakan pada media buku, media ajar konvensional&nbsp; dan kualitas tatap&nbsp; muka.&nbsp; Hal&nbsp; ini memberikan berbagai dampak kepada anak, salah satunya adalah&nbsp; munculnya&nbsp; merasa&nbsp; bosan, kurang antusias&nbsp; dan&nbsp; kurang&nbsp; fokus&nbsp; dalam mengikuti&nbsp; pelajaran. Dikarenakan sebab tersebut maka penelitian dan pengabdian ini diimplementasikan.&nbsp; Perancangan&nbsp; aplikasi&nbsp; ini&nbsp; menggunakan&nbsp; metode Multimedia Development Life Cycle (MDLC) yang dibangun pada platform Android dengan game EngineUnity 3D. Game edukasi ini dinamakan AR HaloKids dengan menggunakan Markerbased tracking.&nbsp;&nbsp; Hasil&nbsp;&nbsp; dari&nbsp;&nbsp; penelitian&nbsp;&nbsp; ini&nbsp;&nbsp; menunjukkan&nbsp;&nbsp; bahwa&nbsp;&nbsp; penggunakan AR HaloKids sebagai alat peraga interaktif&nbsp; yang&nbsp; direpresentasikan &nbsp;dalam bentuk objek 3D, suara serta animasi, mampu meningkatkan ketertarikan dan pengetahuan anak didik dalam mempelajari aneka profesi pekerjaan, alat musik, jenis buah-buahan dan berbagai kebutuhan sehari-hari. Game edukasi&nbsp; ini&nbsp; dapat&nbsp; digunakan&nbsp; sebagai&nbsp; penunjang&nbsp; metode&nbsp; pembelajaran&nbsp; tanpa mengesapingkan alat bantu dan kegiatan belajar-mengajar lainny

Tribocorrosion and tribochemistry of cobalt-chromium alloy used for total hip replacement

Cobalt-based metallic biomaterials are mostly employed as bearing materials for Total Hip Replacement (THR) owing to their high strength, their biocompatibility, as well as their wear and fatigue resistance. Cobalt-chromium-molybdenum (CoCrMo) alloys also have excellent passivity characteristics as an oxide layer can form on the surface spontaneously, reducing corrosion. Nevertheless, mechanical interaction, such as friction and wear, can damage the passive oxide layer and also causes metal products used in such replacements to be released into the human body. The repeated removal of the oxide layer due to joint articulation leads to wear and corrosion; a process termed ‘tribocorrosion’. Due to the complex working environment, as well as the presence of organic elements or species, there remains a lack of knowledge regarding tribocorrosion and the surface film mechanisms. An understanding upon these mechanisms is important since studies have reported that the tribochemical film, a complex metal-protein compound, can enhance the surface protection towards tribocorrosive processes. However, the behaviour is still debatable depending on the working conditions (e.g. temperature, pH, contact load and organic species in the lubricant). The fundamental mechanisms of wear and corrosion are recognised to solve the longevity problem of the orthopaedic implants. Tribocorrosion and tribochemistry of CoCrMo alloys were investigated in various conditions. A reciprocating tribometer, electrochemical cells and surface analysis techniques were employed to observe the tribocorrosive behaviour of CoCrMo samples tested in protein-containing electrolytes. Conditions were applied to investigate various protein-metal interactions regarding behaviour in the tribocorrosion process: (a) in a range of electrochemical potential, (b) with different organic species, (c) protein conditions and (d) with the addition of metal ions in the bulk electrolytes. Results highlighted that a tribocorrosion and tribochemical reactions occurred during sliding are sensitive to the electrolyte composition. These findings contribute to the pre-clinical understanding of protein-metal interactions occurring in tribofilms’ formation and the system variables effect on the metallic bearing surfaces

Investigating the Roles of Protein on the Cobalt Alloy Surface Degradation for Biomedical Implant Through Tribocorrosion Mechanisms

Previous investigation has established the formation of tribofilm is influenced by tribochemical reactions between the electrolyte and the articulating surface of cobalt alloy through sliding tests in various simulated fluids. Although it has successfully characterized the film composition via spectroscopy analysis and indicated to have impact on material loss, a comprehensive understanding of the material degradation mechanism in tribocorrosion condition was still lacking. Therefore, this study aims to investigate the role of protein in the tribocorrosive degradation of cobalt-chromium-molybdenum (CoCrMo) alloy in different simulated physiological electrolytes. Using a similar testing protocol, tribocorrosion tests were conducted with reciprocating ceramic ball against CoCrMo samples immersed in saline and culture medium, compared to both electrolytes diluted with 25% fetal bovine serum (FBS). Synergistic and mechanistic approaches were employed to model the tribocorrosive degradation. Results reveal that protein plays a beneficial role in reducing corrosive (electrochemical) surface degradation under tribocorrosion condition, whilst increasing mechanical wear degradation in the process. Despite studies have shown that tribocorrosion behavior in metal alloys is highly influenced by the presence of organic matter, this study provides a more clarity of the roles played by protein in tribocorrosive degradation on CoCrMo surface as its novel finding

Factors influencing the bio-tribo-corrosion and chemistry on cobalt alloys: A brief literature review

Cobalt-chromium-molybdenum (CoCrMo) alloys are commonly employed for load-bearing implants, such as hip and knee prostheses, owing to their mechanical properties and excellent passivity characteristics to reduce corrosion. The interaction between biological environment and the metallic surface under an articulating condition is extremely complex. The metal is exposed not only to the harsh biological environment as well as mechanical loading, leading to the conjoined action of mechanical (wear) and electrochemical (corrosion) degradations of the material; termed as tribo-corrosion. Tribo-chemical film formation can affect the surface response towards tribo-corrosive processes. The fundamental mechanisms of the tribo-corrosive degradation and surface chemistry are recognized to contribute to the orthopaedic implants’ longevity problem; an understanding of those mechanisms is therefore essential. This manuscript aimed to briefly review the current knowledge of the tribo-corrosion and tribo-chemistry phenomena from the pre-clinical studies’ point of view on the CoCrMo alloys used for hip bearing implants. This overview highlighted that the tribo- corrosion and tribo-chemical reactions during sliding are sensitive to the biological species interaction, as well as several unexplored factors in the environment. These findings contribute to the further knowledge and pre-clinical understanding of protein-metal interactions occurring in films formation and the system variables effect on the metallic load-bearing surfaces