Multi-scale modelling for adhesive wear in tribo-pairs of nano-hydroxyapatite reinforced UHMWPE bio-composite and Co-Cr alloy

2021 ◽  
pp. 146442072110516
Author(s):  
Nishant Verma ◽  
Himanshu Pathak ◽  
Sunny Zafar
Keyword(s):  
Adhesive Wear ◽  
Computational Modelling ◽  
Cytotoxicity Test ◽  
Compression Moulding ◽  
Microstructural Investigation ◽  
Macro Scale ◽  
Scale Modelling ◽  
Modelling Approach ◽  
Worn Surfaces

The ultra-high molecular weight polyethylene (UHMWPE) is a popular biomaterial. Pre-clinical evaluation of UHMWPE in terms of wear resistance is extremely important to avoid the effect of implant loosening after implantation. This work proposed an efficient and accurate computational modelling approach to predict elasto-plastic properties at meso-scale, and further integrated at macro-scale to predict adhesive wear in dry tribo-pairs condition. The representative volume element (RVE) based finite element technique was used to predict elastoplastic behaviour of nano-hydroxyapatite (nHA) reinforced UHMWPE composite. The predicted values were validated experimentally and applied as a material property of pin during a numerical investigation of adhesive wear by a macro-scale modelling approach. The CoCr alloy was taken as the counter disc material. The integration of Archard's wear model and user-subroutine was done for numerical prediction of wear. The numerically obtained wear rate and friction coefficient results were validated experimentally by a pin on the disc wear setup under dry conditions. The fabrication of the specimen for validation was done by microwave-assisted compression moulding (MACM). The microstructural investigation of worn surfaces was done by scanning electron microscopy (SEM) to understand the mechanism of adhesive wear. The surface mapping of worn surfaces was done using an optical profilometer to observe the surface roughness after adhesive wear. Biocompatibility of the composite material was confirmed by In-vitro direct contact cytotoxicity test

scholarly journals Numerical Modelling of the Mechanical Behaviour of Biaxial Weft-Knitted Fabrics on Different Length Scales

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3693 ◽  
Author(s):  
Pham ◽  
Döbrich ◽  
Trümper ◽  
Gereke ◽  
Cherif
Keyword(s):  
Computational Cost ◽  
Parametric Models ◽  
Element Formulation ◽  
Knitted Fabrics ◽  
Macro Scale ◽  
Complex Shapes ◽  
Scale Modelling ◽  
Forming Characteristics ◽  
Meso Scale ◽  
Modelling Approach

Weft-knitted fabrics offer an excellent formability into complex shapes for composite application. In biaxial weft-knitted fabric, additional yarns are inserted in the warp (wale-wise) and weft (course-wise) directions as a reinforcement. Due to these straight yarns, the mechanical properties of such fabrics are better than those of unreinforced weft-knitted fabrics. The forming process of flat fabrics into 3D preforms is challenging and requires numerical simulation. In this paper, the mechanical behavior of biaxial weft-knitted fabrics is simulated by means of macro- and meso-scale finite element method (FEM) models. The macro-scale modelling approach is based on a shell element formulation and offers reasonable computational costs but has some limitations by the description of fabric mechanical characteristics and forming behavior. The meso-scale modelling approach based on beam elements can describe the fabric’s mechanical and forming characteristics better at a higher computational cost. The FEM models were validated by comparing the results of various simulations with the equivalent experiments. With the help of the parametric models, the forming of biaxial weft-knitted fabrics into complex shapes can be simulated. These models help to predict material and process parameters for optimized forming conditions without the necessity of costly experimental trials.

scholarly journals Gut inference: A computational modelling approach

2021 ◽  
pp. 108152
Author(s):  
Ryan Smith ◽  
Ahmad Mayeli ◽  
Samuel Taylor ◽  
Obada Al Zoubi ◽  
Jessyca Naegele ◽  
...  
Keyword(s):  
Computational Modelling ◽  
Modelling Approach

A computational modelling approach to human-elephant interactions in the Bunda District, Tanzania

2021 ◽  
Vol 443 ◽  
pp. 109449
Author(s):  
Abel Ansporthy Mamboleo ◽  
Crile Doscher ◽  
Adrian Paterson
Keyword(s):  
Computational Modelling ◽  
Modelling Approach

A Multi-Scale Modelling Approach and Experimental Calibration Applied to Commercial SOFCs

2017 ◽  
Vol 78 (1) ◽  
pp. 2645-2658 ◽  
Author(s):  
Luca Mastropasqua ◽  
Alessandro Donazzi ◽  
Stefano Campanari
Keyword(s):  
Experimental Calibration ◽  
Multi Scale ◽  
Scale Modelling ◽  
Modelling Approach

scholarly journals UJI SITOTOKSISITAS EKSTRAK DAUN MIMBA (Azadirachta indica) TERHADAP SEL FIBROBLAS BHK 21

2017 ◽  
Vol 7 (1) ◽  
pp. 48
Author(s):  
Qurni Restiani ◽  
Mandojo Rukmo ◽  
Devi Eka Juniarti
Keyword(s):  
Antibacterial Activity ◽  
Optical Density ◽  
Azadirachta Indica ◽  
Root Canal ◽  
In Vitro Study ◽  
Cytotoxicity Test ◽  
Root Canal Irrigants ◽  
Neem Leaves ◽  
Alternative Material

Background: The leaves of neem (Azadirachta indicia) is one of herbal medicine that recommended as an alternative material of root canal irrigants. The active ingredients of neem leaves such as alkaloids, tannins, saponins and flavonoids has been proven to have antibacterial activity against E. faecalis. The ideal properties of an alternative material of root canal irrigants is not only have antibacterial activity but also is not toxic to the tissues, but the toxicity of neem leaves remains unclear until now. Objective: The aims of this study to determine the toxicity effect of neem leaves extract in specific concentration. Methods: This research was an experimental laboratory in vitro study of baby hamster kidney fibroblast (BHK-21). The neem leaves extract was made by maceration method using ethanol 96% and certain dilution performed to obtain various concentrations. Cytotoxicity test was conducted by MTT assay and the optical density was measured using ELISA reader at wavelength of 620 nm. Then, the optical density values were calculated using the formula for determining the number of survival fibroblasts after tested. Results: The percentage of survival fibroblast at concentration of 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95, and 100% in sequence were 71.3%, 64, 2%, 62%, 60.2%, 40.1%, 36.3%, 36.7%, 29%, 28.4%, 27.5%, and 25.6% . Conclusion: The extract of neem leaves (Azadirachta indica) has cytotoxic effects at concentration of 70% up to 100%.

Porous zirconia ceramic as an alternative to dentin for in vitro dentin barriers cytotoxicity test

2017 ◽  
Vol 22 (5) ◽  
pp. 2081-2088
Author(s):  
Meng-Long Hu ◽  
Hong Lin ◽  
Ruo-Dan Jiang ◽  
Li-Min Dong ◽  
Lin Huang ◽  
...  
Keyword(s):  
Zirconia Ceramic ◽  
Cytotoxicity Test ◽  
Porous Zirconia

P–458 A computational biology approach to improve in-vitro folliculogenesis

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
C D Berardino ◽  
N Bernabò ◽  
G Capacchietti ◽  
A Peserico ◽  
G Buoncuore ◽  
...  
Keyword(s):  
Metabolic Control ◽  
Intracellular Signaling ◽  
Assisted Reproductive Technologies ◽  
Computational Modelling ◽  
Reproductive Technologies ◽  
Developmental Competence ◽  
Paracrine Factors ◽  
Oocyte Growth ◽  
Topological Parameters

Abstract Study question Considering the complexity of mechanisms involved in mammalian ovarian folliculogenesis, how about improving the current in-vitro folliculogenesis (ivF) protocols to prolong individual reproductive chance? Summary answer Computational modelling approach based on network theory was used to manage complexity, improve ivF knowledge and discover new molecules to be targeted for innovating assisted-reproductive-technologies. What is known already: Over the past decades, based on the large ovarian-pool of immature-gametes availability, ivF systems were developed in several mammalian species to support oocyte growth in order to preserve human-fertility and contrast endangered species extinction. Only mouse live-births were obtained when primordial/primary follicles were cultured in-vitro, instead the oocyte differentiation is extremely slow in medium-sized mammals. Moreover, the degree of meiotic-competence is quite incomplete if compared to mice, because oocytes must proceed until late antral-follicle stage to acquire a complete developmental competence. These observations denote the importance to adopt further investigations for establishing a complete ivF protocol in translational mammal model. Study design, size, duration Two researchers expert on reproductive biology generated the Web of Science-Mammals-Made in-vitro folliculogenesis (WoS_MMivF) database including 1111 manuscripts published in peer-reviewed international papers indexed selected in Advanced Search of WoS “Core-collection” by carrying out an independent analysis. Two additional researchers verified the correctness of the records. Participants/materials, setting, methods WoS_MMivF network was built up using Cytoscape 2.6.3 software. The network was analyzed for topological parameters (closeness-centrality, betweenness-centrality and edge count) and to identify key controllers (Hub.BN). Bidimensional-kernel-density-estimation (2D KDE) identifies Hub.BN controllers; Search-Tool-for-the-Retrieval-of-Interacting-Genes/Proteins (STRING) were used to enrich the network with new proteins. Main results and the role of chance The analysis of topological parameters demonstrated that the network is scale-free according to Barabási-Albert-model with a high-degree of robustness-against-random-damage, great controllability and navigability. The network reproduces a coherent framework identifying cross-talking molecules playing a key role in the inter-follicular/intra (somatic and germinal compartment) dialogue. The network allows to organize signalling transduction events/molecules by stratifying them in three layers: input-layer recognizes molecules generating the information flux working as systemic endocrine (pituitary/chorion/enteric-related endocrine hormones) and local paracrine-factors (TGFbeta-superfamily-members and growth-factors) exerting either intrafollicular control or remote feedback on reproductive-cycle. Processing-layer presents molecules able to elaborate/amplify the endocrine/paracrine controllers of ovarian functions, including components of codified intracellular-signaling-pathways like PI3K, KIT and MAPK and second messengers cAMP and Ca2+. These cascades are necessary to promote in-vitro reproducible follicular functions and modulate steroidogenesis, representing molecular events stratified in the output-layer. STRING analysis allowed to extend the regulatory flow of information towards two major biological action contexts: metabolic-control (paracrine-factors and signal-transduction) and angiogenesis. Metabolic-control mediated by mTOR and its interactor cognates FOXO1, FOXO3/SIRT1 plays a key role for ivF, representing the energy sensors of the reproductive cells in hypothalamic-pituitary-ovarian-axis first regulating the status of follicle quiescence/activation and then fate of the structure (specialization or apoptosis). Limitations, reasons for caution - Wider implications of the findings: STRING identified mTOR as key pathway of folliculogenesis, which might act as a molecular-switch to be pharmacologically targeted for potential new in-vitro strategies modulating follicular fate. These results suggest that computational approach in biology might offer perspective in identifying unknown signals, implementing research questions and innovative protocols to face female-fertility. Trial registration number Not applicable

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