Abstract: This scientific paper consists of the analysis of the grasshopper jumping mechanism through literature studies, manufacturing, analysis and experimentation to enhance the knowledge to the manufacturing and analyzing of the artificially developed grasshopper-like robots. The first step involved the understanding of the actual grasshopper mechanisms which was carried out by the dissection of actual grasshopper bodies to analyze the hind leg movements, actuating muscles and structured sizes of the involved organs. The next step involved the development structural of the prototype consisted of design of the grasshopper jumping robot and the durability of the structure was checked at the critical locations. The results indicated that the strains produced in the tibia (immediately before and immediately after the jump) and femur of the designed structure was 2.5.10-5, 3.2.10-5 and 634.10-5 respectively. Whereas, the maximum allowable strain of the material during elastic deformation is 660.10-5, so the design of the structure could satisfy the strength requirements. The structural strength of the tibia and femur with the vertical printing were also in line with the stress requirements. Fabrication and jumping test was carried out which indicated 5 times higher jumps for the designed and fabricated grasshopper like jumping robot. This result is very helpful in robotic industry for the smooth movements of the robots for carrying out the intended function on rough terrains.
Abstract: The human knee joint is very critical and complex joint of human body which is responsible for our optimal daily functions. It consists of various bones – femur, tibia, patella, fibula, different ligaments, cartilages, menisci and muscles. FEM is a very useful tool for the analysis of knee joint and various knee replacement products. In the knee replacement surgery a proper understanding of knee joint biomechanics is essential. Because of certain limitations of experimental studies, FEM analysis process is playing a significance role for prominent understanding of knee biomechanics and produced an effective and impressive tool for total knee replacement (TKR/TKA) or partial knee replacement (PKR/PKA). The aim of this paper is to give a review on FEM analysis of human knee joint and knee prosthesis devices and how much adequate this method for these type of analysis.
Abstract: Flatfoot has been one of the most common foot deformity, which gives rise to several malfunctions or disoders to the foot and lower extremity. Difference between flatfoot and normal foot mainly present in the middle foot, while few is known about the biomechanical difference under barefoot vertical jump. The objective of this study is to investigate the difference of flatfoot and normal foot while vertical jumping under barefoot condition. Twenty males (ten with flatfoot and ten with normal foot) volunteered to participate in this study. Foot morphology was measured with Easy-Foot-Scan. Foot kinetics and joint kinematics were obtained from EMED force platform and Vicon motion analysis system. Results showed that flatfoot group had a significantly larger peak pressure in the region of hallux and larger contact area of center forefoot than that of normal foot group, and larger contact area in medial midfoot. The flatfoot group presented larger plantarflexion and smaller external rotation to the ankle, and larger flexion and abduction and smaller external rotation to the knee than normal foot group during vertical jump. It can be concluded that people with flat-arched feet may have a poorer ability of self-regulation when facing a movement with rapid impact force like vertical jump, which will increase the risk of injuries. This information will be valuable for future work in structure, function and potential treatment of low arched feet.
Abstract: The influence of light on Electroencephalogram seems to be more critical, when physician depends on its readings to diagnose subject brain disorder according to its level. Although, bright light brings various changes in human physiological variables. But, Neurophysiological changes for specific light level still remain unclear. Thereby, in the present study, the response of brain electrical activity towards various light levels has been classified and verified. The reasons for alteration in different physiological variables due to bright light which results change in the state of electroencephalographic recordings has been reviewed. Additionally, the effects of bright light towards Ocular artifacts are also put forward. A novel hypothesis has been made using subjective analysis and experimental analysis in low luminance or darkness. It is observed that a poor lighting condition affects both behavioral task and brain activity.
Abstract: With the rapid development of medical imaging technology, computer graphics and visualization technologies, virtual endoscopy technology emerged. It mainly includes 2D medical image segmentation, 3D image reconstruction, path planning and virtual roaming. However, the path planning of virtual endoscopy has become one of the obstacles in this field due to the high irregularity of the nasopharyngeal anatomy structure. In this study, the nasopharynx including meatus nasi, pharyngeal canal, maxillary sinus, frontal sinus, sphenoid sinus, and ethmoid sinus is segmented and 3D reconstructed using MR images. The key technology of virtual endoscopy - center path planning algorithm is implemented based on distance transform. Also, two improved algorithms of center path planning are proposed. One is the selection algorithm of branch path and the other is the extraction algorithm for complex path based on human-computer interaction. These two improved algorithms can not only allow the traditional path planning algorithm to handle multiple branching structure but make roaming path to start at any point. Our experimental results satisfied the needs of clinical practice.
Abstract: Infections after bone implant surgeries have remained one of the leading underlying cause of revision surgery due to implant failure. Despite careful and improved surgery procedures and systemic antibiotic prophylaxis are well practised, the possibility of infection still exists. Many strategies have been studied to prevent post-implant infections, such as anti-bacterial coatings, adhesion resistant coatings, and anti-microbial alloying element. To respond on the challenge of reducing the risks of infections after bone implantations, a review that focused on the effectiveness of anti-bacterial coatings on metallic implants are briefly presented.
Abstract: In this work we accomplished a study concerning the surface state of acrylic prosthetic biomaterials both optimized and non-optimized and we studied their compatibility on test animals. Various methods are seeking to improve the quality of implants and minimally invasive devices for body analysis, the increase of biocompatibility and resistance to corrosion of materials intended to come into contact with biological tissues. Poly (methyl methacrylate) is used in a wide range of applications and offers increased resistance and color stability over time and it can be relatively easy to smooth and polish. The morphology and roughness of the surfaces in case of acrylic prosthetic biomaterials were analyzed by atomic force microscopy that provides qualitative information regarding the chemical uniformity from phase.
Abstract: This work reports evidence of the synthesis of zeolite A at two different temperatures (60 °C and 105 °C) from kaolin. XRD spectral analysis revealed percent crystallinity of 74 ± 2 and 71 ± 3 in LTA60 and LTA105 respectively. The average crystallize size of LTA60 and LTA105 was also estimated using Scherrer’s equation to be 57 nm. FTIR analysis showed signature peaks characteristics of zeolite A in the two materials, except the appearance of absorbance peak at 2380 cm− 1 in the LTA60 spectrum which was not observed in LTA105. Nitrogen porosity measurements of LTA60 and LTA105 gave the following parameters: average pore width of 2.45 and 1.01 nm respectively for LTA60 and LTA105, surface areas of 19.18 and 8.00 m2/g and pore volume of 0.012 and 0.002 cm3/g in that order. The influence of the materials on HeLa cancer cell growth was also investigated and the results showed differential inhibitory effects with LTA60 revealing pronounced inhibitory effects compared to LTA105 after 72 hours of cell incubation. This studies highlighted the importance of crystallization conditions that could influence the physicochemical parameters including structure, porosity, size, and morphology of zeolite materials on cell activity. The work also provided unique opportunities for utilizing natural deposits of kaolin globally to fabricate biomimetic materials for various biological applications.
Abstract: Peripheral nerve injury with gaps between 5 and 30 mm can result in permanent paralysis because axons are cut. The distance between axons, which is more than 1-2 cm, needs graft in the form of nerve connecting pipe in order to repair the defects. A synthesis of hollowfiber polyurethane-collagen coated by chitosan was carried out to identify its potential as treatment accelerator for peripheral nerve injury. The result of Fourier Transform Infrared (FTIR) analysis showed multiple links between chitosan and glutaraldehyde, which can be seen in wavenumber shift from 1080-1100 cm-1 to 1002 cm-1. The degradation test result revealed that the sample displayed mass loss after it was soaked in simulated body fluid (SBF) for seven days. Polyurethane can be degraded in the body after 30 days. This converges with the nerve mechanism that regenerates at the rate of 1 mm/day or 1 inch/month. The result of tensile test indicated that modulus values of chitosan coating variation of 1%, 1.5%, and 2% were 4.75 MPa, 4.74 MPa, and 7.67 Mpa respectively. The outcome of scanning electron microscope (SEM) showed that hollow fiber has a diameter of 2.021-2.032 mm, which matches the diameter of peripheral nerves ranging from 1.5 to 3 mm and the membrane pore size of 31.33-39.65 μm. The result of MTT assay demonstrated that the percentage of viable fibroblast BHK-21 cells was exceeding 50%, which means that the sample does not have toxic properties. The result of this study is expected to provide theoretical basis for the utilization of polyurethane-collagen coating chitosan as nerve graft for theraphy of peripheral nerve injury. The utilization is possible due to the fact that the composite exhibits biocompatible, regenerative, and easily degradable characteristics. Moreover, it could become an alternative solution to answer the need of a more affordable and easier-to-produce nerve graft, so it can be mass-produced in Indonesia.
Abstract: The stable metabolites rate of nitric oxide is reduced three times compared with the rate in the group of control animals in homogenates of rats’ gingival tissue with gastritis and duodenitis. Increasing of the catalase rate with simultaneous increasing of lipids and proteins oxidation was accompanied by decreasing activity of superoxide dismutase. Decreasing of the malonic dialdehyde content and indices protein molecules fragmentation in the blood plasma with simultaneous increasing of catalase and nitric oxide metabolites levels indicates the leading role of nitric oxide in antioxidant protection of the organism in conditions of disease.