scholarly journals Materials for Orthopedic Bioimplants: Modulating Degradation and Surface Modification Using Integrated Nanomaterials

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 264 ◽  
Author(s):  
Harbhajan Ahirwar ◽  
Yubin Zhou ◽  
Chinmaya Mahapatra ◽  
Seeram Ramakrishna ◽  
Prasoon Kumar ◽  
...  

Significant research and development in the field of biomedical implants has evoked the scope to treat a broad range of orthopedic ailments that include fracture fixation, total bone replacement, joint arthrodesis, dental screws, and others. Importantly, the success of a bioimplant depends not only upon its bulk properties, but also on its surface properties that influence its interaction with the host tissue. Various approaches of surface modification such as coating of nanomaterial have been employed to enhance antibacterial activities of a bioimplant. The modified surface facilitates directed modulation of the host cellular behavior and grafting of cell-binding peptides, extracellular matrix (ECM) proteins, and growth factors to further improve host acceptance of a bioimplant. These strategies showed promising results in orthopedics, e.g., improved bone repair and regeneration. However, the choice of materials, especially considering their degradation behavior and surface properties, plays a key role in long-term reliability and performance of bioimplants. Metallic biomaterials have evolved largely in terms of their bulk and surface properties including nano-structuring with nanomaterials to meet the requirements of new generation orthopedic bioimplants. In this review, we have discussed metals and metal alloys commonly used for manufacturing different orthopedic bioimplants and the biotic as well as abiotic factors affecting the failure and degradation of those bioimplants. The review also highlights the currently available nanomaterial-based surface modification technologies to augment the function and performance of these metallic bioimplants in a clinical setting.

2021 ◽  
Vol 8 ◽  
Author(s):  
Jialong Tian ◽  
Zhouhua Jiang

Ultrahigh-strength (UHS) steels have shown great potential in the field of high-end equipment manufacturing in demand of lightweight engineering and performance upgrade. A significant research effort has been directed toward the development of advanced UHS steels with excellent combination of strength and toughness. In the course of development, tailoring precipitates by means of composition design and process optimization is absolutely a critical module. In this mini review, typical UHS steels strengthened by carbides and intermetallics are systematically summarized and discussed. With the increase of strength, the toughness losses of UHS steels strengthened by carbides and intermetallics have been compared in detail. In particular, the in-depth mechanisms leading to various strength/toughness variation trends have been discussed, extracting the bottleneck in developing new-generation UHS steels containing merely one type of precipitate. Meanwhile, prospects on designing advanced UHS steels strengthened by coexisting dispersive precipitates have been proposed to achieve better performance.


2020 ◽  
Vol 99 (4) ◽  
pp. 405-411
Author(s):  
Elena Ju. Gorbatkova

Introduction. The important factors affecting health and performance of young people are the conditions of education, in particular, a comfortable microclimate in the classrooms of higher educational institutions. Materials and methods. In view of the urgency of this problem, an analysis was made of the microclimate parameters of educational organizations of different profiles (Ufa city, the Republic of Bashkortostan). 294 classrooms were studied in 22 buildings of 4 leading universities in Ufa. A total of 3,822 measurements were taken to determine the parameters of the microclimate. The analysis of ionizing radiation in the aerial environment of classrooms. There was performed determination of radon and its affiliated products content. In order to assess the conditions and lifestyle of students of 4 higher educational institutions of the city of Ufa, we conducted an anonymous survey of 1,820 students of I and IV years of education. Results. The average temperature in the classrooms of all universities studied was 23.9±0.09 C. The average relative humidity in all classrooms was 34.2 ± 0.42%. Analysis of ionizing radiation (radon and its daughter products decay) in the aerial environment of the classrooms and sports halls located in the basement determined that the average annual equivalent equilibrium volumetric activity of the radon daughter products (EROA ± Δ222Rn) ranged from 28 ± 14 to 69 ± 34.5 meter, which meets the requirements established by SanPiN. Conclusion. The hygienic assessment of the microclimate parameters of educational institutions of various profile revealed a number of deviations from the regulated norms. The results indicate the need to control the parameters of the microclimate, both from the administration of universities, and from the professors. According to the results of the study, recommendations were prepared for the management of higher educational institutions in Ufa.


2020 ◽  
pp. 097674792096686
Author(s):  
Yudhvir Singh ◽  
Ram Milan

Public sector banks have been merged by the government in the last few years. This is the rationale behind conducting this study. The purpose of this article is to determine the factors affecting the performance of public sector banks in India and the interrelationship between bank-specific determinants and performance of public sector banks. In this article, we shall analyse the financial data of all the public sector commercial banks for a period spread across 11 years (2009–2019); Capital adequacy, Assets quality, Management efficiency, Earning, and Liquidity (CAMEL) has been used as a performance determinant; system generalised method of moments (GMM) analysis has been used to find the effect of determinants on the performance measurement of public sector banks; and CCA (canonical correlation analysis) has been used to find the interrelationship between the bank-specific determinants and the performance of public sector banks. The finding has important implications in terms of performance in the banking sector. Certain limitations of this study are: It is based on secondary data. The study only covers the financial aspects and not the non-financial aspects. It is found that the asset quality is negatively related with performance of public sector banks. Liquidity and inflation are inversely related to performance of public sector banks in India. Capital adequacy is positively related with banks’ performance, but inversely related with banks’ interest margin. GDP growth has a significant positive impact on banks’ performance, but inversely related with banks’ interest income. Inflation rate is inversely related with banks’ performance. Banking sector reforms are insignificantly related with banks’ performance.


2021 ◽  
Vol 22 (2) ◽  
pp. 348-363
Author(s):  
Damian Boniface Sambuo ◽  
Stephen Kirama ◽  
Kitala Malamsha

Determination of fish landing price is important, as the same contributes to the structure, conduct and performance of the fish market in Lake Victoria. Determination of relevant landing price is a gap to console between fishermen, agents (middlemen), processors and the government. The main objective of this study was therefore to examine fish price determination. Specifically, to examine the methods for fish price determination and analyse factors that affect fish landing price in Lake Victoria, a cross-sectional design was employed, and 300 respondents were randomly selected from two district councils, namely, Sengerema and Buchosa. Both qualitative and quantitative data were analysed using descriptive statistics and inferential analysis. Findings show that landing price is determined through formal negotiation with processors, consultation with other traders, informal negotiation with buyers and Beach Management Unit (BMU). The study concluded that these are the common methods used to determine landing prices. Also, distance from fishing to onshore landing centres, market information channels, age and experiences of the fishermen are the factors significantly found affecting landing price. It is recommended that the mechanism for setting up fishery price, fish market structure, fishery information and the formation of fishery regulatory body needs fishery policy and sector reforms that mark the determination of fish landing price.


Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Javed Alam ◽  
Arun Kumar Shukla ◽  
Mohammad Azam Ansari ◽  
Fekri Abdulraqeb Ahmed Ali ◽  
Mansour Alhoshan

We fabricated a nanofiltration membrane consisting of a polyaniline (PANI) film on a polyphenylsulfone (PPSU) substrate membrane. The PANI film acted as a potent separation enhancer and antimicrobial coating. The membrane was analyzed via scanning electron microscopy and atomic force microscopy to examine its morphology, topography, contact angle, and zeta potential. We aimed to investigate the impact of the PANI film on the surface properties of the membrane. Membrane performance was then evaluated in terms of water permeation and rejection of methylene blue (MB), an organic dye. Coating the PPSU membrane with a PANI film imparted significant advantages, including finely tuned nanometer-scale membrane pores and tailored surface properties, including increased hydrophilicity and zeta potential. The PANI film also significantly enhanced separation of the MB dye. The PANI-coated membrane rejected over 90% of MB with little compromise in membrane permeability. The PANI film also enhanced the antimicrobial activity of the membrane. The bacteriostasis (BR) values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Escherichia coli were 63.5% and 95.2%, respectively. The BR values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Staphylococcus aureus were 70.6% and 88.0%, respectively.


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