Judul: Sintesis Hidroksiapatit Berpori Berbasis Kalsium dari Cangkang Telur dan Porogen Lilin dari Sarang Lebah
Abstrak: Kalsium fosfat merupakan senyawa organik yang banyak digunakan dalam aplikasi medis. Jenis kalsium fosfat yang sering dipakai adalah hidroksiapatit (HAp) dan trikalsium fosfat (β -TKF). Sintesis Hidroksiapatit berpori ini dilakukan dengan metode sol - gel. Sintesis HAp berpori dibuat dari CaO, H3PO4, dan lilin lebah. Kalsium oksida (CaO) bersumber dari cangkang telur ayam yang telah dikalsinasi pada suhu 1000oC selama 5 jam. Pengunaan lilin lebah pada proses menghasilkan HAp berpori. Hasil karakterisasi XRD pada sampel menunjukkan hadirnya puncak milik HAp, β – TKF dan AKB. Terbentuknya HAp diperkuat juga dengan hasil karakterisasi spektroskopi FTIR ditandai dengan adanya gugus fosfat (PO4 3-), hidroksil (OH-), dan karbonat (CO3 2), selain itu terdapat juga gugus (C-H), (C=O) dan (C=C) yang menandakan masih adanya lilin yang tersisa pada sampel. Pada karakterisasi SEM juga menunjukkan terbentuknya kalsium fosfat yang ditandai dengan bentuk morfologi sampel yang terdiri dari butiranbutiran yang membentuk pori dengan ukuran pori makro diantara 1,3 μm sampai 2,5 μm.
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Judul: Sintesis dan Karakterisasi Hidroksiapatit Berpori dari Cangkang Kerang Darah (Anadara granosa Linn.) dengan Porogen Lilin Lebah
Abstrak: Calcium phosphate compound is ceramic material that is used as good biomaterial for bones because of its bioactive and good biocompatibility which the composition is same as pure bone. The most stable calcium phosphate compound is hydroxyapatite (HAp) (Ca10(PO4)6OH2). But HAp has low dissolving level, thus porous HAp was made. HAp was synthesized by sol gel methods with main calcium material was provided by Cockle (A. granosa ) and as the porous agent was used beeswax dissolved by ethanol 96%. This research was done by 5 difference concentrations of beeswax, i.e. 10%, 20%, 30%, 40%, and 50%. Synthesis result was analyzed with X-ray diffractometer, scanning electron microscopy, and Fourier transform infrared. The result from X-ray diffractometer analysis showed the best porous HAp in this research used 30% beeswax as porous agent. Scanning microscopy electron analysis result showed big porous formed by using 50% beeswax with average macro porous size was about 1,74 μm and average micro porous size was about 0,245 μm . Calcium phosphate compound was sintered on the temperature 900o C for 5 hours.
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Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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