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Metallic biomaterials are used to replace and rebuild human structural components due to their biocompatibility, corrosion resistance, and good mechanical properties. Biomedical metals have been used for 30 years. Medical implants use metallic biomaterials. Metallic biomaterials are needed to cure failed hard tissue, bone, and fractures. Because they’re strong, tough, and long-lasting. As the world population ages and seniors are more prone to experience hard tissue disintegration, there is a huge demand for improved metallic biomaterials. Titanium-based alloys, cobalt-based alloys, and stainless steel are feasible metallic biomaterials (316L). These biomaterials’ Young’s modulus should match that of human bones, reducing stress shielding. Implant designs include plates, rods, screws, and pins. Since the FDA approved these biocompatible metallic implants, orthopedic practices often employ them. Metals aren’t believable as biomaterials because they’re synthetic and have insufficient bio-functionality. The biocompatibility of metallic biomaterials must be considerably enhanced. Metallic biomaterials are often synthetic materials with no biological activity. The key issue is coating-to-substrate adhesion. Cover spalling from the substrate causes implant and tissue responses. Due to inadequate crystallization, the hydroxyapatite (HA) coating degrades, increasing implant failure risk by lowering titanium adhesion. Coated 316L stainless steel specimens have better adherence than untreated ones. The coating/substrate material, coating process, and coating thickness are thoroughly identified and discussed. The surface structure and microstructure of HA-based coating are explored to support the conclusions.

We developed a model to describe polarized photon scattering in biological tissues. In this model, tissues are simplified to a mixture of scatterers and surrounding medium. There are two types of scatterers in the model: solid spheres and infinitely long solid cylinders. Variables related to the scatterers include: the densities and sizes of the spheres and cylinders, the orientation and angular distribution of cylinders. Variables related to the surrounding medium include: the refractive index, absorption coefficient and birefringence. In this paper, as a development we introduce an optical activity effect to the model. By comparing experiments and Monte Carlo simulations, we analyze the backscattering Mueller matrix patterns of several tissue-like media, and summarize the different effects coming from anisotropic scattering and optical properties. In addition, we propose a possible method to extract the optical activity values for tissues. Both the experimental and simulated results show that, by analyzing the Mueller matrix patterns, the microstructure and optical properties of the medium can be obtained. The characteristic features of Mueller matrix patterns are potentially powerful tools for studying the contrast mechanisms of polarization imaging for medical diagnosis.

Polarimetry is a powerful optical tool in the biomedical field, providing more comprehensive information on the sub-wavelength micro-physical structure of a sample than traditional light intensity measurement techniques. This review summarizes the concepts and techniques of polarization and its biomedical applications. Specifically, we first briefly describe the basic principles of polarized light and the Mueller matrix (MM) decomposition method, followed by some research progress of polarimetric measurement techniques in recent years. Finally, we introduce some studies on biological tissues and cells, and then illustrate the application value of polarization optical method.

Computational simulation of the thermal transport phenomena in the human body has recently aroused a great deal of interest among researchers, because it can be applied in different areas such as medicine, rehabilitation, space suits, and others. In this study, we developed a coupling model to analyze the temperature distribution of the human middle finger. Firstly, a one-dimensional thermo-fluid model of blood circulation in the human upper limb is constructed. Secondly, a two-dimensional thermal model of the human finger, which consists of skin, tendon, bone, main arteries, and veins is developed. The two models are further coupled weakly through data transfer. The blood pressure, blood flow rate, and blood temperature at different vessel sites and the tissue temperature are thus obtained. The effect of viscosity on the finger skin temperature was also investigated. Simultaneously, the thermograms of the human hand were also obtained using thermograpy under the resting condition and after jogging, to observe the variation in the blood circulation. The temperature at different points was extracted from the thermograms. It is observed that there is a periodic variation in skin temperature near the blood vessels after jogging. It is expected that this coupling model will be applicable to hyperthermia, drug delivery, and sports training.

A mathematical and numerical study is presented for simulating temperature distribution in a two-dimensional tissue medium using Pennes bioheat transfer equation, when the tissue is subjected to ultrasonic waves. Following nondimensionalization of the governing partial differential equation, a novel variational iteration method (VIM) solution is developed. This excellent technique introduced by He [Variational iteration method — a kind of non-linear analytical technique: Some examples, Int J Non-Linear Mech.34:699–708, 1999] employs Lagrange multipliers which can be identified optimally via variational theory. The space and time distributions of temperature are studied and solutions visualized via Mathematica. The influence of thermal conductivity and relaxation time are also examined. Excellent stability and convergence characteristics of VIM are demonstrated. Validation is achieved with a Chebyschev spectral collocation method (CSCM). The present work demonstrates the excellent potential of this powerful semi-numerical method in nonlinear biological heat transfer and furthermore provides an alternative strategy to conventional finite element and finite difference computational simulations. The model finds applications in minimally-invasive spinal laser treatments, glaucoma therapy in ophthalmology and thermoradiotherapy for malignant tumors.