Abstract: The growing popularity of endurance sports activities is associated with a growing number of running injuries among recreational runners. The aim of this study was to assess the kinematic and kinetic variation on biomechanical parameters before and after 5km of treadmill running in female runners. Fourteen habitually shod female runners were assessed during treadmill running at their self-selected 5km running speed. A VICON motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematic and plantar pressure data. Key findings from the study were that the internal and external rotation angle of the ankle, hip and knee while pre-5k running showed significant differences to those evaluated post-5k. The peak values of ground reaction forces (GRF) recorded pre-5k running were larger than the forces measured post-5k running. Combining the inversion and eversion of the ankle in the coronal plane during the pushing off phase, post-5k running showed a bigger eversion angle than pre-5k running. These subtle differences may reﬂect adaptation of motor control in female runners during long distance running of 5km.
Abstract: The human knee is a complex joint (the largest joint of the human body). During the different daily activities, this joint is exposed to significant loads and movements, may in some cases exceed the limit of the mechanical capacities of its components, which shows that the pathologies are quite numerous at the level of the human knee and the treatment sometimes requires surgery to either repair or implant (implant total knee prosthesis). As we know very well, the success of a total knee implant is highly dependent on the initial stability of the femoral or tibial implant and the integration of femur and tibia bone tissue with these implants in the long term. Due to the optimal distribution of mechanical stresses in the surrounding bone. It is for this reason that the search for reasonable solutions to compensate the damaged knee prosthesis and reduce the stresses in the cortical bone and spongy has become a very important research axis. In this regard, we have proposed three models of prosthesis knee joint from available literature and study the distribution of Von-Mises stresses and strains in the differents composents of knee prosthesis, know the total displacement between the model intact and model artificial of knee, 3D modeling software Solidworks 2016 is used for 3D modeling of knee prosthesis and finite element analysis software ANSYS 16.2 is used for numerical estimation of von-Mises stresses and strains. We find in this study that the maximum stresses and strains of Von Mises at the level of the tibia and tibial bone decrease, that is to say that the cement and the elastomer play a very important role in the absorption of the stresses and their minimization. On the other hand, the four knee prostheses (Model I (Ti6Al4V), Model II (CoCrMo), Model III (316L SS), Model IV (ZrO2)) implanted by elastomer contribute significantly to the reduction of stresses in the patella bone compared to the Intact Model. In general, both models of the knee prosthesis and reinforced by a stress reduction system (cement, elastomer) gave a lower stress level in the tibia and tibial bone of a normal person compared to a healthy model. The results obtained provide a theoretical basis for choosing an appropriate surgical model.
Abstract: The number of supporting dental implants is an important criterion for the surgical outcome of dental bridge fixation, which has considerable impact on biomechanical load transfer characteristics. Excessive stress at the bone–implant interface by masticatory loading may result in implant failure. The aim of this study was to evaluate the impact of the number of implants supporting the dental bridge on stress in neighboring tissues around the implants. Results of the study will provide useful information on appropriate surgical techniques for dental bridge fixation. In this study, osseointegrated smooth cylindrical dental implants of same diameter and length were numerically analyzed, using three-dimensional bone–implant models. The effect of the number of supporting implants on biomechanical stability of dental bridge was examined, using two, three and four supporting implants. All materials were assumed to be linearly elastic and isotropic. Masticatory load was applied in coron-apical direction on the external part of dental bridge. Finite Element (FE) analyses were run to solve for von Mises stress. Maximum von Mises stresses were located in the cervical line of cortical bone around dental implants. Peak von Mises stress values decreased with an increase in the number of implants that support the dental bridge. Results of this study demonstrate the importance of using the correct number of supporting implants to for dental bridge fixation.
Abstract: The main originality of this work consists in investigating low cycle fatigue of AISI 316L cardiovascular stents under hypertensive loading. For this purpose, two geometries of stents are expanded to various diameters and subjected to hypertensive blood pressure. Based on a combination between the fatigue parameter of Jiang-Sehitoglu and the relationship of Coffin-Manson, a numerical model for the prediction of the number of cycles to crack failure is developed. The stent is found to exhibit a fatigue life reduction with the increase of the expansion diameter due to ratchetting strain. In addition, the location of the failure is independent on the design. However, the U-shape strut permits a better distribution of pressure over the stent strut resulting in a longer fatigue life as compared to the Ω-shape.
Abstract: Retinal fundus image is important for the ophthalmologist to identify and detect many vision-related diseases, such as diabetes and hypertension. From an acquisition process, retinal images often have low gray level contrast and low dynamic range. This problem may seriously affect the diagnostic process and its outcome, especially if an automatic computer-based procedure is used to derive diagnostic parameters. In this paper, a new proposed method based on statistical information such as mean and standard deviation was studied. The combination of local and global technique was successful to detect the luminosity region. Then, a simple correction intensity equation was proposed in order to replace the problem intensity. The results of the numerical simulation (SNR = 2.347 and GCF = 4.581) indicate that the proposed method effective to enhance the luminosity region. Implications of the results and future research directions are also presented. Keywords: Detection, Luminosity, Retinal, Statistical.
Abstract: Coronary atherosclerotic plaque has been extensively studied in pathological research. Improving the evaluation of vulnerable rupture is important to prevent acute heart failure. Intravascular ultrasound (IVUS) method is one of techniques to acquire information about atherosclerotic plaque, which is backscattered ultrasound signal sensed by IVUS transducer. The vessel structure and tissue components are then characterized in relation to the acquired signals. In this study, eight human coronary vessel sections are involved, and we use discriminative restricted Boltzmann machine (RBM) to classify coronary tissues as a target classifier. The quantization domain of IVUS signals are used to extract binary features for adapting Gaussian model of RBM. In addition, we propose a misclassification sensitive training of disRBM to deal with the class imbalances. The results are compared to the conventional integrated backscattered IVUS method (IB-IVUS) and the cost sensitive neural network for the same tasks.
Abstract: The common blood bag in the market is made from a mixture of PVC and plasticizer. But the a number of occurrences where pockets of heavily polluted bacteria, blood requires blood bags which has the antibacterial characteristic. Antibacterial properties on the bags of blood can be raised with the addition of chitosan. This research aim is to know the influence of chitosan membrane biocomposite PVC-Glycerol against its biological and physical properties. Chitosan dissolved with a concentration of 0 wt/v%; wt/v 0.5%; 1 wt/v%; 1.5 v/wt% wt/v and 2 wt/v% mixed with glycerol with a 1:1 ratio. Then the mixture was mixed with PVC solution 15% and formed into a membrane by using the glass plates. Furthermore, the membranes are characterized using tensile test, hemolytic test, and antibacterial test. The physical characteristics of the tensile test indicate that the elongation percentage was 2.22 – 96.43% and tensile strength was 3.6-8 MPa. The test result of the hemolytic test and antibacterial test showed that biocomposite membrane of PVC-Glycerol-Chitosan are hemocompatible because it has a hemolysis percentage < 5%, while antibacterial test results showed that the membrane has a weak anti-bacterial due to bacterial inhibition zone diameter < 5 mm. Based on the characterization result, biocomposite membrane of PVC-Glycerol-Chitosan can be used for blood bag candidate.
Abstract: Based on data from Indonesian Health Ministry in 2009, osteoporosis case reached 19,7 % of the populations in Indonesia, especially women in menopause period. The treatment was performed by consuming bisphosphonate drugs per oral which was not effective since the absorption intake of the drug was only less than 55% of the intake dosage. Because of that, the bone filler which also has a function as drug delivery system was developed. The hydroxyapatite-gelatin bone filler with the addition of alendronate was studied. To increase the characteristics of this bone filler, glutaraldehyde was introduced in the composite as a crosslinking agent. The concentration of 0.25%, 0.5%, and 0.75% were used. The bone filler was then characterized based on FTIR test, morphology test, compressive strength test, cytotoxicity test, and degradation test. The FTIR result showed that there was no significant difference between the sample with and without glutaraldehyde since the crosslinking bond of glutaraldehyde and gelatin was C=N bond which also presented in the gelatin. The morphology of the samples depicted a bigger pore size for higher glutaraldehyde concentration which also supported by lower compressive strength. All the samples were non-toxic based on the cytotoxicity test which had cell viability more than 100%. The degradation tests showed that with the presence of glutaraldehyde in the bone filler could maintain its form longer than the bone filler without glutaraldehyde. In conclusion, the presence of glutaraldehyde could increase the characteristics of the hydroxyapatite-gelatin composite with the addition of alendronate as a bone filler candidate for osteoporotic bone.
Abstract: Coating of magnetic nanoparticles (MNPs) is usually a requirement prior to their utilization in biomedical applications. However, coating can influence the magneto-structural properties of MNPs thereby imparting their applications. The present work highlights the combustion synthesis of Na-doped lanthanum manganites (LNMO) and the influence of silica coatings on the magneto-structural properties, colloidal stability and antimicrobial properties of LNMO MNPs with their biomedical applications in mind. The crystalline perovskite structure was the same both for the bare and silica coated LNMO samples while there was a slight increase in crystallite size after coating. The FTIR spectral analysis, reduction in agglomeration of the particles and the elemental composition of the coated nanoparticles confirmed the presence of silica. The magnetization values of 34 emu/g and 29 emu/g recorded for bare and coated LNMO samples, respectively show that LNMO MNPs retained its ferromagnetic behaviour after silica coating. The pH dependent zeta potentials of the coated sample is-22.20 mV at pH 7.4 (physiological pH) and-18 mV at pH 5.0 (cell endosomal pH). Generally, silica coating reduced the antibacterial activity of the sample except for Bacillus spp where the antibacterial activity was the same with the bare sample. These results showed that while silica coating had marginal effect on the crystalline structure, size and magnetization of LNMO MNPs, it reduced the antibacterial activity of LNMO MNPs and enhanced greatly the colloidal stability of LNMO nanoparticles. Keywords: Na-doped lanthanum manganites, Silica coating, magnetic nanoparticles, biomedical applications, antimicrobial properties, colloidal stability