Judul: Modifikasi pori Hidroksiapatit dari Tulang Ikan Alu-alu (Sphyraena barracuda)
Abstrak: Hydroxyapatite (HAp) is an important material used in biomedical implants. Currently, porous HAp is widely explored. Large pores surface improve osteoconductivity and adsorption strength. Fish bone can be used as source of HAp since it has high level of calcium and phosphorus in the form of mineral apatite. Therefore, the objective of this study was to modify porous Hap from alu-alu (Sphyraena barracuda) fish bone with starch as the porogen. HAp was formed at temperature of 500, 750, 1000, 1250, 1300, and 1350 ºC. cConcentrations of starch used for porogen were 5, 10, 20, 40, and 60% w/w. X-ray diffraction pattern indicated that HAp was formed in the initial powder fish bone but it had low crystalinity and some impurities. HAp phases with good crystallinity were formed at temperatures of 750–1250 ºC. Electron microscope photographs showed pores with good uniformity was exhibited in the modification using fish bone material with starch concentration of 10%; the sizes were 2.38-3.28 μm.
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Judul: Sintesis Hidroksiapatit Berpori dengan Porogen Polivinil Alkohol dan Pati
Abstrak: Hydroxyapatite (HAp) is a material resembles to structure of the human hard tissue. This material can be used for bone implantation. The ideal HAp is that with porosity of 100-150 μm in size. The porous HAp is used as a medium for the formation of bone tissue that grows and can enhance bone regeneration. Therefore, the synthesis of porous Hap was performed byprecipitation-sonication using sea shells Protothaca as the source of calcium and H3PO4 as the source of phosphorous. HAp pore structure was formed by adding various concentrations of polyvinyl alcohol (PVA) and starch at 10%, 15%, and 20%. Phase analysis of samples was carried out by x-ray diffraction (XRD), and morphological analysis by scanning electron microscopy (SEM). XRD results showed that, overall, the samples contain HAp phase. In addition, there were other phases of HAp such as apatite carbonate type A and type B, CaO and CaCO3. Based on SEM analysis, the best pore size was established by the addition of 15% concentratiton of PVA and starch, with the size of 2.89 μm and 2.81 μm, respectively.
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Judul: Analisis faktor dan model persamaan struktural unyuk pengujian model bipolaritas dan dualitas
Abstrak: Perilaku sosial merupakan fenomena yang menarik untuk diamati. Fred Kerlinger, seorang peneliti yang tertarik dengan masalah-masalah sosial, mengamati · perilaku Sistem Liberalis dan Sistem Konservatifpada 530 guru di Texas dan North Carolina [Kerlinger, 1986]. Kerlinger menemukan suatu fenomena dimana masyarakat cenderung menganggap bahwa kedua sistem tersebut adalah dua ha! yang bertolak belakang. Pendapat inilah yang kemudian dikenal sebagai Model Bipolar. Selain itu ada pendapat lain yang mengatakan bahwa kedua sistem merupakan dua ha! yang berdiri sendiri-sendiri dan saling terpisah. Pendapat ini kemudian dikenal sebagai Model Dualitas. Permasalahannya adalah menentukan mana diantara kedua model tersebut yang lebih tepat dalam menjelaskan fenomena yang ada. Hal inilah yang membuat Kerlinger melakukan perbandingan terhadap kedua model dengan cara melakukan pengujian terhadap kedua sistem dengan menggunakan data berupa korelasi variabel­variabel observasi yang mewakili kedua sistem tersebut. Proses pengujian dilakukan dengan menggunakan dua metode analisis, yaitu : Analisis Faktor dan Model Persamaan Struktural. Hasil dengan Analisis Faktor menunjukan bahwa Model Dualitas lebih tepat dalam menjelaskan fenomena yang ada. Hal ini juga didukung oleh Model Persamaan Struktural.
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