Judul: Biokompatibilitas Tandur Tulang Kombinasi Hidroksiapatit Asal Cangkang Telur Ayam dengan Kombinasi Trikalsium Fosfat, dan Kitosan pada Remodelling Tulang Domba Akibat Trauma Buatan
Abstrak: Every year, thousands of people suffer from various bone diseases caused by trauma, tumors, or fractures. Loss and substantial damage to the bone and in various operations such as removal of bone tumors, hip joint prosthesis fitting, and other bone damage have increased the need for allograft bone. This condition is exacerbated by the lack of an ideal bone substitute (Murugan and Ramakhrisna 2004). As a result, it takes a variety of synthetic materials to limit the amount of tissue used in the allograft bone. Although commercially bone substitute materials are available (eg. Osteocel® Plus, cancellous Vitoss® Synthetic Bone Filler, OrthoBlast® II, etc.) but none of were to be made in Indonesia. Moreover, the commercial material or fabric weave is still confidential. Another disadvantage of commercial bone substitute materials is their high price and limited availability in Indonesia. The objective of this study was to determine the best choice of bone substitution between combinations of hydroxyapatite-tricalcium phosphate (HATKF) and hydroxyapatite-chitosan (HA-K) for bone damage healing in sheep. The outcome of the study is expected to: (1) provide information about the efficacy of the two types of bone substitutes in terms of biocompatibility, osteoinduktif, and mechanical stability, (2) as a bone substitute material alternatives on the market, and (3) as the basis for its use in humans. We concluded that HA-TKF and HA-K implants did not cause significant disruption to the body. The healing process in the control bone were faster than both types of implanted bone grafts. However HA-TKF has good biocompatibility, biodegradability, bioresorbability, bioactivity and osteo conductivity properties than HA-K. Both types of implants have the potential to utilized as a bone substitute with further modifications such as: providing nanopore, changes in the composition of the implants, the use of implants in different bone, etc.
Keyword: Hydroxyapatite, Tricalcium phosphate, Khitosan, Biocompatibility, Bone graft

Judul: Kajian Morfologi Proses Persembuhan Kerusakan Segmental Pada Tulang Domba Yang Diimplan Dengan Komposit Hidroksiapatit-Trikalsium Fosfat (HA-TKF)
Abstrak: This study was aimed to evaluate in vivo osteogenesis potency of bones implanted with graft of hydroxyapatite-tricalcium phosphate (HA-TCP) composite. This study also observed the potential use of HA-TCP as bone substitution material. Three local sheeps were used in this study. The implant was inserted under aseptic surgery on the proximal medial of the left tibia bone and as control the proximal medial of the right tibia bone was drilled without implant. Bones were harvested after 30, 60, and 90 days post-surgery and observed macroscopic and microscopically. The parameters of observation were the condition, shape and degradation degree of the implant, bonding between implant and host bone, new bone growth into the implant and signs of inflammation reaction around the implant. The result showed that the healing process on control bone was faster than those of the implanted bone. The bone implant had been already degradated in treated group of day 30 post-surgery. HA-TCP bone implant shown some signs for its biocompatibility, biodegradability, bioresorbability and osteoconductivity properties. Therefore, it is suggested that HA-TCP implant might be used as bone substitution in the bone lesions with approximately 30 days of recovery.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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