Bio-Medical Materials and Engineering - Volume 31, issue 2

Authors: Shams, Maha | Sagheer, Alaa

Article Type: Research Article

Abstract: BACKGROUND: A neurological disorder is one of the significant problems of the nervous system that affects the essential functions of the human brain and spinal cord. Monitoring brain activity through electroencephalography (EEG) has become an important tool in the diagnosis of brain disorders. The robust automatic classification of EEG signals is an important step towards detecting a brain disorder in its earlier stages before status deterioration. OBJECTIVE: Motivated by the computation capabilities of natural evolution strategies (NES), this paper introduces an effective automatic classification approach denoted as natural evolution optimization-based deep learning (NEODL). The proposed classifier is an …ingredient in a signal processing chain that comprises other state-of-the-art techniques in a consistent framework for the purpose of automatic EEG classification. METHODS: The proposed framework consists of four steps. First, the L1-principal component analysis technique is used to enhance the raw EEG signal against any expected artifacts or noise. Second, the purified EEG signal is decomposed into a number of sub-bands by applying the wavelet transform technique where a number of spectral and statistical features are extracted. Third, the extracted features are examined using the artificial bee colony approach in order to optimally select the best features. Lastly, the selected features are treated using the proposed NEODL classifier, where the input signal is classified according to the problem at hand. RESULTS: The proposed approach is evaluated using two benchmark datasets and addresses two neurological disorder applications: epilepsy disease and motor imagery. Several experiments are conducted where the proposed classifier outperforms other deep learning techniques as well as other existing approaches. CONCLUSION: The proposed framework, including the proposed classifier (NEODL), has a promising performance in the classification of EEG signals, including epilepsy disease and motor imagery. Based on the given results, it is expected that this approach will also be useful for the identification of the epileptogenic areas in the human brain. Accordingly, it may find application in the neuro-intensive care units, epilepsy monitoring units, and practical brain-computer interface systems in clinics. Show more

Keywords: Deep learning, natural evolution strategies, artificial bee colony, L1-principal component analysis, neurological disorder, EEG signal classification

DOI: 10.3233/BME-201081

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 2, pp. 73-94, 2020

Authors: Takayama, Tomohiro | Ishihara, Masayuki | Sato, Yoko | Nakamura, Shingo | Fukuda, Koichi | Murakami, Kaoru | Yokoe, Hidetaka

Article Type: Research Article

Abstract: BACKGROUND: Scallop shell powder is called bioshell calcium oxide (BiSCaO), which is known to possess deodorizing properties and broad antimicrobial activity against various pathogenic microbes, including viruses, bacteria, spores, and fungi. OBJECTIVE: This study aims to investigate the applications of BiSCaO suspension cleansing in clinical situations, for instance for the prevention and treatment of infections in chronic wounds in healing-impaired patients, without delaying wound healing. METHODS: The bactericidal activities of 1000 ppm BiSCaO suspension; 500 ppm hypochlorous acid; 1000 ppm povidone iodine; and saline were compared to evaluate in vivo disinfection and healing of Pseudomonas aeruginosa –infected wounds in …hairless rats. RESULTS: Cleansing of the infected wounds with BiSCaO suspension daily for 3 days significantly enhanced wound healing and reduced the in vivo bacterial counts, in comparison to hypochlorous acid, povidone iodine, and saline. Furthermore, histological examinations showed significantly advanced granulation tissue and capillary formation in the wounds cleansed with BiSCaO suspension than in those cleansed with the other solutions. CONCLUSIONS: This study suggested that the possibility of using BiSCaO suspension as a disinfectant for infected wounds and limiting disinfection to 3 days may be sufficient to avoid the negative effects on wound repair. Show more

Keywords: Bioshell calcium oxide (BiSCaO), hypochlorous acid, microbicidal activity, infected wound, wound repair

DOI: 10.3233/BME-201082

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 2, pp. 95-105, 2020

Authors: Tateiwa, Toshiyuki | Takahashi, Yasuhito | Pezzotti, Giuseppe | Shishido, Takaaki | Masaoka, Toshinori | Sano, Keiji | Yamamoto, Kengo

Article Type: Research Article

Abstract: BACKGROUND: Accelerated hydrothermal aging has long been one of the most widely accepted quality control tests for simulating low-temperature degradation (LTD) in zirconia-containing implants used in total hip arthroplasty (THA). However, it is still unclear how much consistency there is between the experimental prediction from the internationally-standardized tests and the actual measurements from surgically-removed implants after a long period of implantation. This question is fundamentally related to a lack of understanding of mechanical/tribological contribution to the in-vivo LTD kinetics. OBJECTIVE: The main purpose of this study is to validate the clinical relevance of standardized accelerated aging by …comparing artificially-aged and in-vivo used prostheses, and to clarify the long-term effects of in-vivo mechanics/tribology on the LTD progression upon service in the body environment. METHODS: Surface magnitudes of phase transformation and residual stress in zirconia femoral head retrievals (13.1–18.4 yrs) were evaluated by using confocal Raman microspectroscopy. RESULTS: The long-term aging behavior in unworn head surface was in agreement with the experimental prediction estimated as 1 h aging at 134 °C = 4 years in-vivo . However, the current aging protocols based on ASTM and ISO criteria were not accurately predictive for the worn surfaces, and the tribologically-induced phase transformation and tensile stress were up to 6.5-times and 3.3-times higher than the environmentally-induced ones. CONCLUSION: Our study suggests that wear/scratching, frictional heating, tribochemical reactions, and metal transfer may become far more intense triggers to phase transformation than the mere exposure to body fluid. Show more

Keywords: Aging kinetics, zirconia, femoral head, phase transformation, residual stresses

DOI: 10.3233/BME-201083

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 2, pp. 107-117, 2020

Authors: Sakoda, Hideyuki | Sugano, Nobuhiko | Okamoto, Yoshihiro | Haishima, Yuji

Article Type: Research Article

Abstract: BACKGROUND: Fourier-transform infrared spectroscopy (FTIR) is one of the standard methods to analyze ultra-high molecular weight polyethylene (UHMWPE) in orthopedic implants. For retrieved components, lipid extraction using an organic solvent prior to the measurement is necessary to eliminate the influence of lipids absorbed in vivo . However, its influence on the measurement has not been substantially investigated. OBJECTIVE: To investigate the influence of lipid extraction on the FTIR analysis of UHMWPE and to develop a novel method to obtain reliable results without inconvenient lipid extraction. METHODS: FTIR analysis was repeatedly performed on UHMWPE specimens from …retrieved components before and after lipid extraction under various conditions. A method to calculate the extent of influence of the absorbed lipids from the FTIR spectra was developed using a peak separation technique. RESULTS: An elevated temperature was necessary for lipid extraction; however, it had the potential to influence the results if the conditions were not properly controlled. The results obtained using the peak separation technique coincided with those obtained after lipid extraction. CONCLUSION: The use of the peak separation technique enables the efficient acquisition of reliable results without the need for lipid extraction. Show more

Keywords: Oxidation index, lipid index, retrieval study, oxidative degradation, lipid index subtracted oxidation index (s-OI)

DOI: 10.3233/BME-201084

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 2, pp. 119-129, 2020

Authors: Linek, Pawel | Wolny, Tomasz | Myśliwiec, Andrzej | Klepek, Anna

Article Type: Research Article

Abstract: BACKGROUND: There are no studies on the scoliotic population in which lateral abdominal muscle (LAM) was measured. OBJECTIVE: The aim of the study was to deliver the first results on LAM elasticity assessed by shear wave elastography (SWE) in right-side and left-side thoracolumbar scoliosis patients. METHOD: Twelve patients (mean age 12.25) with thoracolumbar scoliosis were included in the study. Muscle thickness and SWE of the obliquus external (OE), obliquus internal, and transversus abdominis (TrA) were measured with an ultrasound scanner. Measurements were taken at rest and during isometric contraction. RESULTS: An analysis showed that …in right-side scoliosis, the OE muscle on the convex side was stiffer by 7.25 kPa compared to the concave side. The OE muscle on the convex side in right-side scoliosis was also stiffer by 11.6 kPa compared to the convex side in left-side scoliosis. In left-side scoliosis, the TrA muscle on the concave side was stiffer by 7.84 kPa compared to the convex side. CONCLUSION: Changes in LAM elasticity of thoracolumbar scoliosis were observed. A different pattern of LAM stiffness in different curve directions may be expected. OE and TrA shear moduli are the most sensitive to change in adolescent spinal deformation. Show more

Keywords: Shear wave elastography, shear modulus, scoliosis, adolescents

DOI: 10.3233/BME-201085

Citation: Bio-Medical Materials and Engineering, vol. 31, no. 2, pp. 131-142, 2020