Judul: Conversion of Borate-Based Bioglass to Hydroxyapatite in Phosphate Solution and Mixed of Phosphate and Carbonate Solution
Abstrak: Bioaktivitas material dengan sel merupakan salah satu parameter utama biokompatibilitas material yang berperan dalam regenerasi jaringan tulang baru. Biomaterial dengan luas permukaan yang besar mampu meningkatkan adhesi sel yang berperan dalam inisiasi regenerasi jaringan baru. Salah satu modifikasi untuk meningkatkan bioaktivitas material adalah pembuatan material dalam bentuk mikrosfer. Dalam penelitian ini dilakukan fabrikasi mikrosfer hidroksiapatit melalui konversi mikrosfer bioglass dalam larutan fosfat serta larutan campuran fosfat dan karbonat. Mikrosfer bioglass diperoleh melalui metode flame spray spheroidization dengan bahan baku dasar partikel bioglass berukuran 63 μm – 200 μm. Citra SEM menunjukkan bahwa mikrosfer bioglass berhasil difabrikasi dengan ukuran rata-rata 76,84 μm. Konversi mikrosfer bioglass dilakukan dengan variasi waktu pengamatan selama 14 hari. Hasil pola difraksi sinar-X menunjukkan bahwa mikrosfer kalsium fosfat untuk kedua larutan terbentuk pada hari ke-7 dan terdapat fasa apatit karbonat (CHA) pada hasil uji konversi dalam larutan campuran fosfat dan karbonat. Citra SEM pada hasil konversi menunjukkan bahwa ukuran mikrosfer kalsium fosfat memiliki rentang yang sama dengan ukuran mikrosfer bioglass sebelum uji konversi yaitu sebesar 73,59 μm – 90,83 μm. Hasil EDX menginformasikan bahwa mikrosfer kalsium fosfat memiliki rasio Ca/P yang mendekati literatur., The bioactivity of the material with cells is one of the main parameters for the biocompatibility of the material that plays a role in the regeneration of new bone tissue. Biomaterials with a large surface area are able to increase cell adhesion which plays a role in the initiation of new tissue regeneration. One of the modifications to increase the bioactivity of the material is the manufacture of the material in the form of microspheres. In this study, the fabrication of hydroxyapatite microspheres was carried out by converting bioglass microspheres in phosphate solution and a mixed solution of phosphate and carbonate. Bioglass microspheres were obtained through the flame spray spheroidization method with the basic raw material of bioglass particles measuring 63 μm – 200 μm. The SEM image shows that the bioglass microspheres were successfully fabricated with an average size of 76.84 μm. The conversion of bioglass microspheres was carried out by varying the observation time for 14 days. The results of the X-ray diffraction pattern showed that calcium phosphate microspheres for both solutions were formed on day 7 and there was an apatite carbonate (CHA) phase in the conversion test results in a mixed solution of phosphate and carbonate. The SEM image on the conversion results shows that the size of the calcium phosphate microspheres has the same range as the size of the bioglass microspheres before the conversion test, which is 73.59 μm – 90.83 μm. The EDX results inform that calcium phosphate microspheres have a Ca/P ratio close to the literature.
Keyword: Bone Graft, Carbonate Apatite, Flame Spray Spheroidization, SEM-EDX, XRD

Judul: Fabrikasi dan Karakterisasi Mikrosfer Bioactive Glass Terdoping Yttrium (Y-90)
Abstrak: Tulang merupakan organ penting dalam tubuh yang berperan sebagai penggerak, pendukung dan pelindung jaringan lunak,tempat penyimpanan kalsium dan fosfat, serta tempat penyimpanan sumsum tulang. Hal ini menjadikan kesehatan tulang menjadi salah satu prioritas kesehatan nasional. Salah satu permasalahan tulang yang banyak terjadi pada berbagai rentang usia adalah kanker tulang sehingga membutuhkan pengobatan intensif untuk membunuh sel kanker. Salah satu metode terapi yang dianggap lebih efektif dibanding metode terapi lainnya adalah terapi radiasi internal karena bersifat lokal pada target sehingga mampu mengurangi efek radiasi pada sel sehat di sekitarnya. Dalam terapi kanker tulang, terapi radiasi internal dikembangkan tidak hanya untuk membunuh sel kanker tetapi juga memicu regenerasi jaringan tulang baru. Oleh sebab itu, diperlukan biomaterial berbentuk mikrosfer terdoping bahan radioaktif yang berperan sebagai double agent dalam terapi kanker tulang. Penelitian ini bertujuan untuk fabrikasi dan karakterisasi mikrosfer bioactive glass terdoping yttrium (Y90) dengan variasi konsentrasi. Fabrikasi mikrosfer bioactive glass terdoping yttrium dilakukan melalui metode flame spray spheroidization menggunakan gas oxy/acetylene dengan rasio 7:6. Starting material yang digunakan untuk fabrikasi mikrosfer adalah partikel bioactive glass berukuran 10 - 125 µm yang terlebih dahulu difabrikasi melalui metode melting-quenching dengan penambahan Y2O3 dengan variasi konsentrasi (0 – 2.5%). Hasil karakterisasi XRD menunjukkan struktur alamiah partikel atau mikrosfer bioactive glass berfasa amorf. Pola difraksi sinar-X yang sama juga terlihat pada partikel dan mikrosfer bioactive glass terdoping yttrium. Hal ini menunjukkan penambahan yttrium tidak merubah struktur fasa bioactive glass. Citra SEM menunjukkan tidak adanya pengaruh penambahan ytrrium terhadap morfologi bioactive glass. Citra SEM juga menunjukkan keberhasilan metode flame spray spheroidization dalam menghasilkan mikrosfer bioactive glass terdoping yttrium dengan ukuran rata-rata sebesar 76-87 µm. Adapun hasil EDX menunjukkan persentase berat elemen yttrium yang semakin besar seiring dengan penambahan Y2O3 dalam formulasi bioactive glass. Sebaliknya, semakin besar penambahan Y2O3 maka persentase elemen natrium semakin berkurang secara linear karena adanya substitusi prekursor Y2O3 terhadap Na2CO3 dalam formulasi bioactive glass. Kata kunci: flame spray spheroidization, hidroksiapatit, kanker tulang, radiasi internal, SEM-EDX, XRD., Bone is an important organ in the body acting as locomotor, support and protection of soft tissues, calcium and phosphate storage, and harboring of bone marrow. Therefore, bone health is categorized as one of the national health priorities. One of the bone problems that often occurs in various age is bone cancer, so it requires intensive treatment to kill the cancer cells. Internal radiation therapy is one of cancer therapies that is considerably more effective among others due to the localized treatment to the target leading to reduce the effects of radiation on surrounding healthy cells. In bone cancer therapy, internal radiation therapy was developed to not only kill cancer cells but also induce newly bone tissue regeneration. Therefore, biomaterials are needed in the form of radioactive microspheres acting as a double agent in bone cancer therapy. This study aims to fabricate and characterize yttrium (Y-90)-doped bioactive glass microspheres with various concentrations. The fabrication of yttrium-doped bioactive glass microspheres was carried out through the flame spray spheroidization method using oxy/acetylene with a gas ratio of 7:6. The starting material used for the microsphere fabrication was irregular bioactive glass particles with
Keyword: flame spray spheroidization, hidroksiapatit, kanker tulang, radiasi internal, SEM-EDX, XRD

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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