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Abstrak :
Microstructural identification of synthesized steel with significant local content has been carried out. Alloy ingot was prepared using a casting technique. The samples were then formed into bulk steel by a machining process. A high resolution powder neutron diffractometer (HRPD) was used as an equipment for characterization. By applying neutron diffraction techniques, a ferritic steel profile can be resulted in as well as ‘minor peaks’ belong to impurities formed in the sample. These impurities can be identified as small amounts of Al2O3 54SiO2, Al4C3, SiC and Cr23C6. Scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDX) confirmed and revealed neutron identified phase distributions. Joint Committee on Powder Diffraction Standards (JCPDS) least square curves calibration can precisely calculate the dhkl parameters of each reflection plane. As a comparison, another sample of alloy ingot was also investigated using neutron diffraction. The pattern was free from crystal impurities. Rietveld refinements provide satisfactory goodness of fits Rwp = 10.42% and reliability factor S = 1.7. This was so-called a ‘real bulky’ sample of a 73Fe24Cr2Si0.8Mn0.1Ni ferritic steel alloy.

Abstrak :
Pendahuluan: Perubahan sistem pertahanan pejamu atau kondisi rongga mulut dapat menyebabkan infeksi Candida albicans (C. albicans) yang disebut kandidiasis oral. Xanthorrhizol adalah komponen aktif Temulawak (Curcuma xanthorrhiza Roxb.) yang memiliki efek antijamur. Gambar Scanning Electron Microscope (SEM) sel C. albicans yang terpapar xanthorrhizol menunjukkan penonjolan sitoplasma dan adhesi antar sel. Tidak diketahui bagaimana perubahan ultrastruktural pada sel C. albicans. Tujuan: Menggunakan TEM untuk menganalisis perubahan ultrastruktur sel C. albicans pada biofilm fase pematangan pasca-inhibisi dengan Ekstrak Etanol Temulawak (EET). Metode: Biofilm C. albicans ATCC 10231 yang ditumbuhkan pada kawat selama 1,5 jam dihambat dengan 25% EET selama 48 jam. Kelompok kontrol positif tidak diberi nistatin sedangkan kelompok kontrol negatif tidak diberi apa-apa. Sampel difiksasi dengan 2,5% glutaraldehid, didehidrasi dengan etanol, dan dibenamkan dalam resin spurr sebelum diamati dengan TEM. Hasil: Terlihat distorsi dinding sel, membran plasma, dan organel serta invaginasi membran plasma. Kesimpulan: Penghambatan biofilm C. albicans ATCC 10231 oleh 25% EET menyebabkan kerusakan pada ultrastruktur sel C. albicans ATCC 10231.

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Changes of hosts defense system or oral condition causing infection of Candida albicans (C. albicans) is called oral candidiasis. Xanthorrhizol is an active component of javanese turmeric (Curcuma xanthorrhiza Roxb.) which has antifungal effect. C. albicans cells Scanning Electron Microscope (SEM) image exposed to xanthorrhizol showed cytoplasm protrusion and clumping. The ultrastructure changes inside the C. albicans cell is not known yet. Objective: Using TEM to analyse the ultrastructure image of C. albicans ATCC 10231 cells in maturation phase of biofilm inhibited by 25% EET. Methods: C. albicans ATCC 10231 biofilm which had been cultured on wire for 1.5 hours was inhibited by 25% EET. Group of positive control was exposed by nystatin whereas group of negative control was exposed to nothing. Sampel was being fixated with glutaraldehyde 2.5%, dehydrathed by ethanol, and embedded inside spurrs resin before being observed with TEM. Results: Cell wall, plasma membrane, and organelles distortion, along with plasma membrane invagination. Conclusion: C. albicans ATCC 10231 biofilm inhibition with 25% EET caused damages in C. albicans ATCC 10231 cells ultrastructure.