Bio-Medical Materials and Engineering - Volume 16, issue 4
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Bio-Medical Materials and Engineering is to promote the welfare of humans and to help them keep healthy. This international journal is an interdisciplinary journal that publishes original research papers, review articles and brief notes on materials and engineering for biological and medical systems.
Articles in this peer-reviewed journal cover a wide range of topics, including, but not limited to: Engineering as applied to improving diagnosis, therapy, and prevention of disease and injury, and better substitutes for damaged or disabled human organs; Studies of biomaterial interactions with the human body, bio-compatibility, interfacial and interaction problems; Biomechanical behavior under biological and/or medical conditions; Mechanical and biological properties of membrane biomaterials; Cellular and tissue engineering, physiological, biophysical, biochemical bioengineering aspects; Implant failure fields and degradation of implants. Biomimetics engineering and materials including system analysis as supporter for aged people and as rehabilitation; Bioengineering and materials technology as applied to the decontamination against environmental problems; Biosensors, bioreactors, bioprocess instrumentation and control system; Application to food engineering; Standardization problems on biomaterials and related products; Assessment of reliability and safety of biomedical materials and man-machine systems; and Product liability of biomaterials and related products.
Abstract: Most human tissues do not regenerate spontaneously; this is why cell therapies and tissue engineering are promising alternatives. The principle is simple: cells are collected in a patient and introduced in the damaged tissue or in a tridimentional porous support and harvested in a bioreactor in which the physico-chemical and mechanical parameters are controlled. Once the tissues (or the cells) are mature they may be implanted. In parallel, the development of biotherapies with stem cells is a field of research in turmoil given the hopes for clinical applications that it brings up. Embryonic stem cells are potentially more interesting since…they are totipotent, but they can only be obtained at the very early stages of the embryo. The potential of adult stem cells is limited but isolating them induces no ethical problem and it has been known for more than 40 years that bone marrow does possess the regenerating functions of blood cells. Finally, the properties of foetal stem cells (blood cells from the umbilical cord) are forerunners of the haematopoietic system but the ability of these cells to participate to the formation of other tissues is more problematic. Another field for therapeutic research is that of dendritic cells, antigen presenting cells. Their efficiency in cell therapy relies on the initiation of specific immune responses. They represent a promising tool in the development of a protective immune response against antigens which the host is usually unable to generate an efficient response (melanomas, breast against cancer, prostate cancer, …). Finally, gene therapy, has been nourishing high hopes but few clinical applications can be envisaged in the short term, although potential applications are multiple (haemophilia, myopathies, …). A large number of clinical areas stand as candidates for clinical applications: leukaemia and cancers, cardiac insufficiency and vascular diseases, cartilage and bone repair, ligaments and tendons, liver diseases, ophthalmology, diabetes, neurological diseases (Parkinson, Huntington disease, …), … Various aspects of this new regenerative therapeutic medicine are developed in this work.
Abstract: To evaluate the influence of Zn on the formation of hydroxyapatite (HA), zinc-containing glass 58S4Z was prepared by substitution of CaO with 4 wt% ZnO in 58S bioactive glass, and Zn-containing simulated body fluid (ZnSBF) was prepared as soaking fluid. During the soaking, all samples could induce the deposition of HA, but 58S4Z in SBF and 58S in ZnSBF showed lower formation rate of HA than 58S in SBF, which suggests that both the Zn in glass and the Zn2+ in soaking fluid retarded the deposition of HA. The ICP and EDS analysis results indicated that the main factor…was the preferential reaction of Zn2+ with PO4 3− , which resulted in a decrease of the PO4 3− concentration in soaking fluid and the nucleation of HA. Besides the inhibitory effect of Zn2+ in the soaking fluid, Zn in 58S4Z glass caused a lower release rate of Ca2+ in the initial soaking periods because of the lower CaO content as compared with 58S, and resulted in a lower nucleation rate of HA. The results suggested that small amount of Zn in bioactive glass retarded the nucleation of HA, but with the exhaustion of Zn2+ by PO4 3− , it did not affect the long-term deposition of HA in SBF.
Abstract: The aim of this study was to investigate the effect of one step adhesives on the shear bond strength of a compomer restorative material to both enamel and dentine. Human extracted teeth were used for the study. Ten samples were prepared for both enamel and dentine specimens for each of the five groups: Tooth, no etch, Prime and Bond NT (P+B NT); tooth, Non-Rinse Conditioner (NRC), P+B NT; tooth, NRC, Prime and Bond 2.1 (P+B 2.1); tooth, etch, P+B NT; tooth, etch, P+B 2.1. The specimens were subjected to bond testing. The shear bond strength was measured using an Inston…1193 testing machine using a cross head speed of 1 mm/minute. The specimens were tested to destruction. The results show that for the enamel specimens the highest bond strength was recorded for those specimens subjected to Etch, P+B 2.1 (22.1 MPa) and Etch P+B NT (20.0 MPa). The groups of specimens which did not undergo etching had very low bond strengths ranging from 11.4 MPa for NRC, P+B 2.1, 8.5 MPa for NRC P+B NT to 6.9 MPa for P+B NT. For the dentine specimens, for all of the groups, the shear bond strengths were low. Those groups subjected to etching produced the highest values of 7.9 MPa for NRC P+B 2.1 with the lowest value of 6.1 MPa for NRC P+B NT. These bond strengths were significantly lower than those achieved for bonding to enamel. Prime and Bond NT and Prime and Bond 2.1, used in conjunction with acid etching, produce satisfactory bond strengths of compomer restorative material to enamel. Bond strengths to dentine were low.
Keywords: Compomer, bond strength, enamel, dentine
Abstract: Hydroxyapatite (HA) was coated onto titanium implants using radio frequency magnetron sputtering. The HA films were crystallized in an autoclave tube using low temperature hydrothermal treatment. The average film thickness on the implant was 1.1 μm. HA-coated and pure-titanium implants were inserted into canine mandibles for up to 24 weeks. Forty-eight implants were placed in eight beagles. After 2, 4, 12 and 24 weeks, implants were retrieved and prepared for histological observation, and the HA film thickness was determined using energy-dispersive X-ray spectroscopy. Light microscopy revealed that, after two weeks, the bone response to the HA-coated implants was much better…than to the pure titanium implants, and osteoblasts were observed at the bone–implant interface. After four weeks, the screw threads of the HA-coated implants were almost completely covered with bone. The HA film thickness rapidly decreased up to four weeks of implantation, then gently decreased, reaching 0.40±0.03 μm at the upper region of the implant after 12 weeks. That indicates that about 80% of the HA film had dissolved after 12 weeks of implantation. The rate of decrease in the HA film thickness was greater with increasing implant depth.
Abstract: The bone samples used in clinical and experimental trials must be the less damaged as possible to avoid alterations of their properties. However, the mode of storage might possibly alter the bone properties, particularly microarchitecture and strength. The aim of our study was to analyze the effects of deep-freezing and alcohol conservation techniques on the densitometric, microarchitectural and biomechanical parameters of rat femurs. The left femurs were elongated in uniaxial tension up to breakdown in order to calculate biomechanical parameters. The densitometric and microarchitectural properties of right femurs were evaluated using dual-energy X-ray absorptiometry and microcomputed tomography, respectively. Results showed…no significant difference in the parameters investigated between deep-freezing, alcohol storage and fresh femurs when comparing each parameter separately. Therefore, one month storage in alcohol or deep-freezing seemed to induce no harmful effect on densitometric, microarchitectural and biomechanical parameters of rat femurs.
Abstract: Eight fresh porcine lumbar spines received a posterior instrumentation at L4–L5 using pedicle screw–rod system. Each specimen was tested utilizing laminectomies of varying extent. Group A (Integrity) preserved the spinous process and interspinous ligament; Group B (Partial laminectomy) removed the inferior portion of L4 spinous process and preserved the interspinous ligament of L3–L4; Group C (Complete laminectomy) removed the entire L4 spinous process. Hydraulic testing machine was used to generate an increasing moment up to 8400 N mm in flexion and extension. The intervertebral displacement on the superior adjacent disc between L3–L4 was measured using an extensometer. Under extension, no significant…difference in the intervertebral displacement was observed among three different models of laminectomy. However, under flexion, the intervertebral displacement on adjacent disc with complete laminectomy was statistically larger than those of integrity and partial laminectomies (P=0.000976 and P=0.0363, respectively). No difference was found between integrity and partial laminectomy groups (P>0.05). This study implies that an instrumented spine with integrity of posterior complex is less likely to develop adjacent instability than a spine with destruction of the anchoring point for supraspinous ligament.
Abstract: The purpose of this study was to evaluate principal component analysis method to power spectral density acquired with autoregressive modeling (AR) of carotid artery Doppler signals. Carotid artery Doppler signals from patient with atherosclerosis and healthy subjects were recorded. Afterwards, power spectral densities of these signals were obtained using AR method. The basic differences between the healthy and patients were obtained with 1st principal component obviously. These results could be extrapolated to situations involving noninvasive measurement where PCA can be extremely time saving. As a result the patient and healthy groups are separated clearly from each other via an arbitrary…power function y=ax with perfect accuracy resulting in a precision sensitivity and specificity of 100 percent and the use of PCA of physiological waveform is presented as a powerful method likely to be incorporated in future medical signal processing.
Keywords: Atherosclerosis, carotid artery, power spectral density, principal component analysis, autoregressive
Abstract: This paper aims to develop an enhanced rehabilitation and assessment system for people with impaired leg muscles, and for people who need to improve their leg muscle function. Through interactive design and real time evaluation, medical staff can totally control the training situation for patients and therefore provide a better training program, so that overall a better treatment performance can be achieved. The system consists of four major parts. Sensory and signal conversion circuits convert the lever arm lengths and muscle strengths of the leg into a proper electronic signal and then deliver this to the computer. Then, the intelligent…and interactive interface design lets a trainee complete the training process independently without the involvement of medical staff. In addition, the trainee can see the training results at the end of the training process on the computer screen. The training protection and evaluation mechanism effectively monitors the training situation, based on the individual status settings by the medical staff, and thus any further impairment can be avoided. The database management system is developed to store related personal data, system settings and training results, which can then be retrieved for control and assessment. In comparison to similar equipment the proposed system demonstrates a much better performance, particularly in system functions, accuracy, operation and costs.
Keywords: Leg muscle, assessment, signal conversion