Colorectal carcinoma is a major health concern worldwide and its high incidence and mortality require accurate screening methods. Following endoscopic examination, polyps must be removed for histopathological characterization. Aiming to contribute to the improvement of current endoscopy methods of colorectal carcinoma screening or even for future development of laser treatment procedures, we studied the diffusion properties of glucose and water in colorectal healthy and pathological mucosa. These parameters characterize the tissue dehydration and the refractive index matching mechanisms of optical clearing (OC). We used ex vivo tissues to measure the collimated transmittance spectra and thickness during treatments with OC solutions containing glucose in different concentrations. These time dependencies allowed for estimating the diffusion time and diffusion coefficient values of glucose and water in both types of tissues. The measured diffusion times for glucose in healthy and pathological mucosa samples were 299.2 ± 4.7 ?? s and 320.6 ± 10.6 ?? s for 40% and 35% glucose concentrations, respectively. Such a difference indicates a slower glucose diffusion in cancer tissues, which originate from their ability to trap far more glucose than healthy tissues. We have also found a higher free water content in cancerous tissue that is estimated as 64.4% instead of 59.4% for healthy mucosa.
One the mechanisms of failure in total hip arthroplasty in cemented prosthesis is cement fatigue. The main objective of this work is to use Acoustic Emission (AE) as a non-destructive and non-intrusive monitoring test in a cemented prosthesis. The femoral component was sinusoidally loading in a fatigue machine. Experimental data collected during acoustic emission test was treated and analysed by Wavelet Transform and allowed to locate a crack in cement mantle of femoral component. Other complementary diagnostic tests were used to confirm the existence of a fault (crack). One of them was penetrating liquids in different cut sections of femoral component. The other one was microscopic analysis that allowed observing the existence of a crack which location is pointed out by the results of AE answer. The AE sources locations are situated inside the crack observed in the optical microscope. The Wavelet Transform (WT) AE signals demonstrated the accuracy of damage location in bone cement and thus becoming useful in other orthopedics studies.
Engineering has a very important role in the development of non-destructive monitoring of orthopaedical systems allowing the evaluation of its integrity. Sir John Charnley revolutionized the field of joint arthroplasty in the 1960s with the development of the total hip replacement. He replaced the diseased hip joint with a steel femoral component and a plastic acetabular socket cup combination, both fixed into the bone using a self-curing acrylic cement, polymethylmethacrylate (PMMA) (Browne et al, 2005). That way, he has restored some of the most problematic joints in the human body. The placement of the metal implant in the channel open in the femoral bone without using cement or by mechanical attack, called a non cemented arthroplasty, came into use in an effort to solve the problem. A study about prostheses reviews, between 1979 and 2005, show that's were higher in non-cemented prosthesis, leading to studies on new forms of interface bone/metal. The growth of cemented arthroplasties has been observed since 2005. By Ramos (Ramos et al, 2005), cemented arthroplasty is one of the most successful surgical techniques in orthopaedics. However, the cemented prosthesis has a tendency to fray during the time of their life due to stress and fatigue of the cement material leading to it cracking. The growing importance of different Total Hip Arthroplasty (THA) studies is due to increased life expectancy of the population and its social and clinical relevance. Interdisciplinary THA studies such as: biomechanics (Bergmann et al, 2001;Fonseca et al, 2010;Nabais, 2006;Ramos et al, 2005; Stolk et al, 2006;Teixeira et al, 2008; Vieira, 2004); finite element analysis (Bachtar et al, 2006;Nizam Ahmad et al, 2006;Ridzwan et al, 2006) and acoustic emission monitoring (Browne et al, 2005;Cristofolini et al, 2003;Davies et al, 1996;Franke et al, 2004;Gueiral, 2008;Qi et al, 2005;Qi, 2000;Rowland et al, 2004) have been published. Research has been done to improve the performance of artificial implants, addressing factors such as geometry, materials, cements, and other surgical techniques that directly or indirectly, might influence the performance and success of cemented arthroplasty. Although the lifetime of a THA is between 10 and 15 years, there are factors that lead to loss of prosthesis such as the separation of the femoral prosthesis due to the splitting of connection between the implant/cement and cement/bone. The human body responds through its immune system causing inflammation and pain in osseous structure, which in most cases leads to the replacement of the prosthesis.
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