yrammuS 要概109Suprijanto110Anggraini BarlianUnderstanding the Resonance Scattering Phenomenon on the Interaction between Ultrasound Wave and Needle in Soft Tissue: toward to Needle Visibility Enhancement on Medical Ultrasound-Guided for Needle Insertion (Project 2018)Stem Cell Application in Tissue Engineering for Back Pain Injury (Project 2018)75In ultrasound imaging for needle guiding application, the physicians have to adjust a certain insertion angle and the position of the transducer for ensuring the initial point of insertion and final target of the needle is in-plane in the imaging plane. In clinical application, one of the crucial problems is that needle visibility is not consistent. Potential parameters that affect needle visibility need to be identified because they determine the performance of the interventional procedure. This research aims to study the aspects of fundamental physics that underlie needle visibility by simultaneously combining three aspects of the system as a whole through simulation of ultrasound wave propagation, i.e., frequency of ultrasound as the source, the geometry and di-mension of the needle as the object, and the angle of incident of ultrasound beam as the parameter of interac-tion between the source and the object. In this case, the needle is modelled as rigid cylinder where the stylet is attached to the hollow cylinder. The stainless-steel needles are simulated under the insonation of incident ul-trasound plane waves in water as background medium. The incident angles are varied between 00-450 in the range of frequencies between 0-10 MHz. The spectra of scattering pressure amplitude demonstrate that the peak of resonances occur in certain areas that can be identified from the critical angles αL, αT, and αR. The big-ger the size of the needle, the higher the chance to find the peak of resonances. In other words, the chance to find good visibility of the needle is higher for bigger needle. The spectrum of resonance scattering pressure amplitude for bigger needle tend to be presence in lower frequencies than the smaller ones.Degeneration of annulus fibrosus (AF) in intervertebral disc (IVD) is one of a major reasons in lower back pain injury. Tissue engineering to construct chondrocytes cells became annulus fibrosus (AF), is a novel approach to overcome this problem. The aim of the proposed research is to create the suitable microenvironment for human Adipose-derived Mesenchymal Stem Cells (hADSC) to proliferate and differentiate towards the chon-drocytes cells lineage in biomaterial scaffold. hADSC were obtained from liposuction method will be charac-terized and cultured on biomaterial scaffold in modified microenvironment (low glucose, hypoxia 2% dan low glucose, hypoxia 5%) condition that mimic the condition in IVD in vivo. The proliferation and differentiation process will be analyzed by MTT assay result and expression of Collagen II as marker of chondrogenic dif-ferentiation. Result shows that low glucose microenvironment and 5% oxygen concentration was the best condition to support chondrogenic differentiation of hADSC.Rep. Grant. Res., Asahi Glass Foundation (2019)
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