American Journal of Biomedical Engineering 

About: American Journal of Biomedical Engineering is an academic journal. The journal publishes majorly in the area(s): Signal & Brain–computer interface. It has an ISSN identifier of 2163-1050. It is also open access. Over the lifetime, 130 publications have been published receiving 1027 citations.

Biomedical Magnesium Alloys: A review of material properties, surface modifications and potential as a biodegradable orthopaedic implant

Abstract: Magnesium and magnesium based alloys are lightweight metallic materials that are extremely biocompatible and have similar mechanical properties to natural bone. These materials have the potential to function as an osteoconductive and biodegradable substitute in load bearing applications in the field of hard tissue engineering. However, the effects of corrosion and degradation in the physiological environment of the body has prevented their wide spread application to date. The aim of this review is to examine the properties, chemical stability, degradation in situ and methods of improving the corrosion resistance of magnesium and its alloys for potential application in the orthopaedic field. To be an effective implant, the surface and sub-surface properties of the material needs to be carefully selected so that the degradation kinetics of the implant can be efficiently controlled. Several surface modification techniques are presented and their effectiveness in reducing the corrosion rate and methods of controlling the degradation period are discussed. Ideally, balancing the gradual loss of material and mechanical strength during degradation, with the increasing strength and stability of the newly forming bone tissue is the ultimate goal. If this goal can be achieved, then orthopaedic implants manufactured from magnesium based alloys have the potential to deliver successful clinical outcomes without the need for revision surgery.

Nanodimensional and Nanocrystalline Calcium Orthophosphates

Abstract: Nano-scaled particles and crystals play very important roles in biological systems. For example, calcium orthophosphates (CaPO4) with nano-size dimensions represent the basic inorganic building blocks of bones and teeth of mammals. According to recent discoveries in biomineralization, zillions of nanodimensional crystals of biological apatites are nucleated in body fluids, and afterward, they are self-assembled into these complex structures. In addition, both a greater viability and a better proliferation of various types of cells have been detected on smaller crystals of CaPO4. All these effects are due to the higher surface-to-volume ratio, increased reactivity, and biomimetic morphologies of the nano-scaled particles. Thus, the nano-sized and nanocrystalline forms of CaPO4 have a great potential to revolutionize the hard tissue engineering field, starting from bone repair and augmentation to controlled drug delivery systems. Therefore, preparation and application of nanodimensional CaPO4 are the important topics in modern material science, and such formulations have been already tested clinically for various purposes. Currently, more efforts are focused on the possibility of combining nano-scaled CaPO4 with cells, drugs, and other biologically active substances for multipurpose applications. This chapter describes current state-of-the-art and recent developments on the subject, starting from synthesis and characterization to biomedical and clinical applications.

Lung Cancer Detection by Using Artificial Neural Network and Fuzzy Clustering Methods

Abstract: The early detection of lung cancer is a challenging problem, due to the structure of the cancer cells, where most of the cells are overlapped with each other. This paper presents two segmentation methods, Hopfield Neural Network (HNN) and a Fuzzy C-Mean (FCM) clustering algorithm, for segmenting sputum color images to detect the lung cancer in its early stages. The manual analysis of the sputum samples is time consuming, inaccurate and requires intensive trained person to avoid diagnostic errors. The segmentation results will be used as a base for a Computer Aided Diagnosis (CAD) system for early detection of lung cancer which will improve the chances of survival for the patient. However, the extreme variation in the gray level and the relative contrast among the images make the segmentation results less accurate, thus we applied a thresholding technique as a pre-processing step in all images to extract the nuclei and cytoplasm regions, because most of the quantitative procedures are based on the nuclear feature. The thresholding algorithm succeeded in extracting the nuclei and cytoplasm regions. Moreover, it succeeded in determining the best range of thresholding values. The HNN and FCM methods are designed to classify the image of N pixels among M classes. In this study, we used 1000 sputum color images to test both methods, and HNN has shown a better classification result than FCM, the HNN succeeded in extracting the nuclei and cytoplasm regions.

Sub-THz Vibrational Spectroscopy of Bacterial Cells and Molecular Components

Abstract: In this work, sub-terahertz (THz) spectroscopy is applied to characterize lyophilized and in vitro cultured bacterial cells of non-pathogenic species of Escherichia coli (E. coli) and Bacillus subtilis (BG), spores of BG and DNA fro m E. coli. One of the goals of this research is to demonstrate that Fourier Transform (FT) spectroscopy in the frequency region of 10- 25 cm -1 is sensitive enough to reveal characteristic spectral features fro m bio-cells and spores in different environment, to verify the d ifferences between species, and to show the response of spores to vacuum and response of cultured cells to heat. The experimental technique was significantly improved for sensitivity and reliab ility. Observed spectra taken with a spectral resolution of 0.25 cm -1 using FT spectrometer with a detector operating at 1.7 K are rich in well resolved features having spectral widths of ~0.5-1 cm -1 . The reproducibility of experimental results was verified and confirmed. Measured spectra from E. coli DNA and from the entire cell have many similarit ies, thus demonstrating that the cellu lar co mponents might contribute to the v ibrational spectrum of the cell. The results of this work confirm that observed spectroscopic features are caused by fundamental physical mechanism of interaction between THz rad iation and biological macro-mo lecules. Particu larly, the analysis of results indicates that the spectroscopic signatures of microorganis ms originate fro m the co mbination of low frequency vibrational modes or group of modes at close frequencies (vibrational bands) within mo lecular co mponents of bacterial cells/spores, with the significant contribution from the DNA. The significance of this study is justified by necessity for a fast and effective, label free and reagent free optical technology to protect against environmental and other biological threats, as well as for general medical research. The obtained results show that THz v ibrational spectroscopy promises to add quantitative genetic information to the characteristic signatures of biological objects, increasing the detection accuracy and selectivity when appropriate spectral resolution is used.

Evaluation of the Effects of a Moderate Intensity Static Magnetic Field Application on Human Osteoblast-Like Cells

Abstract: There is a general interest in the effects of magnetic fields on human tissue, for bio medical imaging, cancer therapy or tissue engineering applications. In particular the orthopaedic field may greatly benefit fro m magnetic scaffolds, magnetic fixation and magnetic delivery techniques. In this study, MG-63 osteoblast-like cells were analysed in vitro after exposure to a 320mT static magnetic field (SMF), either continuously or applied fo r 1h at any 24-hour interval. Results demonstrate that SMF causes a reduction in cell nu mber after 7 days of exposure, as demonstrated by the MTT assay. This reduction in proliferation is not associated to an increase in Lactate Dehydrogenase production, a marker of cellu lar stress and/or disruption of memb rane integrity. Osteocalcin secretion increased at day 3 for the condition 1h/day exposure and this effect was reversed after 7 days. Instead, the continuous application of a SM F resulted in a significantly decreased osteocalcin release at day 7. Cell distribution, morphology and cytoskeleton organization were unaltered, with the typical osteoblastic morphology maintained and normal distribution of cytoplasmic actin fibrils, as demonstrated by phalloidin staining. Gene expression analysis of COL1A1, A LPL and RUNX2 show no alterations respect to control. These results suggest that such a moderate intensity static magnetic field has a detrimental effect on cell proliferation and osteocalcin secretion, while maintaining morphological features and gene expression unaltered. The in vitro effects of magnetic fields depend on cell type, magnetic field intensity and modality of applicat ion. Th is study gives a contribution to understand moderate strength static magnetic field effects on human tissue, with particular importance for the orthopaedic field.