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Abstrak :
Pengelasan dissimilar banyak dilakukan untuk mengoptimalkan kebutuhan aplikasi dan rekayasa dengan pertimbangan ekonomi. Sifat-sifat mekanis dan ketahanan terhadap korosi sambungan las sangat dipengaruhi oleh jenis, ukuran, orientasi dan distribusi struktur mikro sambungan las tersebut. Pengaruh dan perubahan struktur mikro akan dipelajari pada pengelasan dissimilar antara baja karbon A36 dan SS 304 untuk posisi pengelasan 1G, 2G, 3G dengan variasi ketebalan 6 mm, 8mm, 10 mm, 12 mm. Hasil pengelasan menunjukan bahwa posisi pengelasan dan ketebalan sambungan las mempengaruhi struktur mikro baik pada HAZ maupun inti las-lasan (weld metal). Ukuran, distribusi dan orientasi struktur mikro menjadi lebih halus dan merata dengan naiknya ketebalan sambungan las-lasan. Pada HAZ baja karbon memperlihatkan struktur GB ferrite dominan untuk posisi pengelasan 1G sedangkan untuk posisi 2G dan 3G memperlihatkan adanya struktur widmanstaten ferrite, martensite dan bainit. Pada daerah dekat fusion line dan inti las terjadi perubahan komposisi kimia akibat proses agitasi, konveksi, difusi dan terjadinya makrosegregasi karena penetrasi cairan logam induk baja karbon kedalam inti las (weld metal) dan pembekuan cepat. Hasil pengujian sifat-sifat mekanik memperlihatkan tegangan tarik putus terjadi pada sisi logam induk baja karbon, hasil test bending menunjukan tegangan yang sangat tinggi pada sambungan las hingga mencapai 887 Mpa dan pengujian kekerasan Vickers menunjukan distribusi kekerasan meningkat pada inti las dan HAZ hingga mencapai nilai HVN 296.9 yakni pada fusion line baja SS 304. Ketahanan korosi khususnya korosi micro-pitting sangat masif terjadi pada bagian inti las khususnya untuk posisi pengelasan 1G dan ketebalan 6 mm dan kurang masif pada HAZ yang secara visual dari foto mikro mengindikasikan pembentukan dan sebaran karbida yang lebih sedikit. Korosi seragam (uniform corrosion) secara galvanik terjadi sangat agresif pada bagian baja karbon. ......Dissimilar metal welding was mostly done to optimize the application and engineering requirements with economic considerations. Mechanical properties and corrosion resistance of welded joints were greatly influenced by weld microstructures. Influences and changes in the microstructure will be studied in the welding of dissimilar metals between carbon steel A36 and stainless steel SS304 with variation of welding position 1G, 2G, 3G and weld thickness of 6 mm, 8 mm, 10 mm, 12 mm. Welding results shown that welding position and thickness of the welded joints influenced the microstructure both in HAZ and weld metal. Size, distribution and orientation of microstructure were finer and more uniform with increasing of welding joint thickness. In HAZ carbon steel, GB ferrite was dominant especially for 1G welding position while for position of 2G and 3G shown other structures such as widmanstaten ferrite, martensite and bainite. In the region near the fusion line and weld metal, the chemical composition changes due to the agitation, convection, diffusion and makrosegregasi caused by penetration of liquid metal carbon steel into the weld pool and quick freezing. The test results showed the mechanical properties of tensile breaking point occurs in the parent metal of carbon steel, bending test results showed a very high stress on the welding joint up to 887 MPa and Vickers hardness testing showed hardness distribution trend increase in the weld metal and HAZ to achieve value for HVN 296.9 at the fusion line of steel SS 304. Corrosion resistance, especially micro-pitting corrosion occurs denser in the weld metal, especially for welding positions 1G and thickness 6 mm and less dense in the HAZ which visually indicates in micro-photographs, the formation and distribution of carbides is much less. Uniform corrosion by galvanic process happens very aggressive on the carbon steel side.

Abstrak :
ABSTRAK
MiR-21 diketahui berperan dalam proliferasi dan diferensiasi osteoklas, namun peran ekspresi miR-21 serum pada osteoporosis masih belum jelas. Penelitian sebelumnya mendapatkan bahwa ekspresi miR-21 serum berkorelasi positif dengan densitas mineral tulang pada penderita osteoporosis pascamenopause, tetapi penelitian tersebut tidak menganalisis faktor-faktor lainnya yang terlibat dalam osteoporosis pascamenopause.Penelitian ini bertujuan untuk mengetahui peran ekspresi miR-21 serum, konsentrasi RANKL, OPG, TGF- ? 1, sklerostin, rasio RANKL/OPG, kalsium serum dan aktivitas fisis terhadap densitas mineral tulang belakang pada perempuan pascamenopause hipoestrogenik dengan osteoporosis dibandingkan dengan tanpa osteoporosis, dengan point of interest pada ekspresi miR-21 serum.Penelitian ini dilakukan dengan disain uji potong lintang komparatif, di RSUD Ulin Banjarmasin, pada bulan Agustus 2015 sampai Juli 2016. Subjek dibagi menjadi 2 kelompok yaitu perempuan pascamenopause hipoestrogenik dengan osteoporosis dan tanpa osteoporosis. Pengambilan sampel dilakukan dengan metode consecutive. Pemeriksaan ekspresi miR-21 serum menggunakan metode absolute quantification real-time PCR. Analisis statistik menggunakan uji korelasi Spearman, Mann-Whitney U test dan regresi linear berganda.Subjek dibagi menjadi 2 kelompok yaitu perempuan pascamenopause hipoestrogenik dengan osteoporosis PMOP dan tanpa osteoporosis PMNOP masing-masing sebanyak 60 subjek. Median ekspresi miR-21 serum pada PMOP lebih tinggi secara bermakna dibandingkan dan PMNOP p = 0,001 . Ekspresi miR-21 serum, RANKL, rasio RANKL/OPG dan aktivitas fisis berkorelasi bermakna dengan nilai BMD pada PMOP. Aktivitas fisis sedang berkorelasi negatif bermakna dengan ekspresi miR-21 serum pada PMOP dan PMNOP. Analisis regresi linear berganda menggunakan metode backward stepwise mendapatkan persamaan regresi linear: BMD = 1,373 - 0,085 Ln.miR-21 - 0,176 Log 10.RANKL R2 = 52,5 .Simpulan. Ekspresi miR-21 serum pada perempuan pascamenopsuse hipoestrogenik dengan osteoporosis terbukti lebih tinggi dibandingkan dengan tanpa osteoporosis. Ekspresi miR-21 serum terbukti memberikan pengaruh negatif terhadap nilai BMD tulang belakang pada perempuan pascamenopause hipoestrogenik dengan osteoporosis sebesar 8,5 , dengan persamaan regresi linear BMD = 1,373 - 0,085 Ln.miR-21 - 0,176 Log10.RANKL. Persamaan ini dapat menjelaskan nilai BMD tulang belakang sebesar 52,5 . Kata kunci: BMD, miR-21 serum, Osteoporosis, Pascamenopause

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ABSTRACT
MiR-21 is known to play a role in osteoclast proliferation and differentiation, but the role of serum miR-21 expression in osteoporosis remains unclear. Previous research found that serum miR-21 expression was positively correlated with bone mineral density in postmenopausal osteoporosis patients, but the study did not analyze other factors involved in postmenopausal osteoporosis.This study aimed to determine the role of serum miR-21 expression, concentration of RANKL, OPG, TGF- ? 1, sclerostin and serum calcium, RANKL/OPG ratio, and physical activity on bone mineral density of spine in hypoestrogenic postmenopausal women with osteoporosis compared to no osteoporosis, with point of interest on the expression of serum miR-21.This study was conducted by comparative cross sectional design, conducted at Ulin General Hospital Banjarmasin, from August 2015 until July 2016. The subjects were divided into 2 groups of hypoestrogenic postmenopausal women with osteoporosis and without osteoporosis. Sampling was done by consecutive method. Examination of serum miR-21 expression using absolute quantification real-time PCR method. Statistical analysis using Spearman correlation test, Mann-Whitney U test and multiple linear regression.The subjects were divided into 2 groups of hypoestrogenic postmenopausal women with osteoporosis PMOP and without osteoporosis PMNOP each as many as 60 people. Median of serum miR-21 expression at PMOP group was significantly higher compared to PMNOP group p = 0.001 . Serum miR-21 expression, RANKL, RANKL/OPG ratio and physical activity were significantly correlated with BMD values ? ? ? ?in PMOP group. Moderate physical activity was significantly negative correlated with serum miR-21 expression. Multiple linear regression multivariate analysis using backward stepwise method obtained linear regression equation BMD = 1,373 - 0,085 Ln.miR-21 - 0,176 Log10.RANKL R2 = 52,5 .Conclusion. Serum miR-21 expression in hypoestrogenic postmenopausal women with osteoporosis has been shown to be higher compared with no osteoporosis. Serum miR-21 expression proved to have a negative effect on spinal BMD values in hypoestrogenic postmenopausal women with osteoporosis of 8.5 , with linear regression equation BMD = 1.373 - 0.085 Ln.miR-21 - 0.176 Log10.RANKL. This equation can explain the value of spinal BMD by 52.5 . Keywords: BMD, Osteoporosis, postmenopausal, serum miR-21

Abstrak :
ABSTRACT
Background: MiR-21 is known to play a role in osteoclast proliferation and differentiation, but the role of serum miR-21 expression in osteoporosis remains unclear. Previous research found that serum miR-21 expression was positively correlated with bone mineral density in postmenopausal osteoporosis patients, but other factors involved in postmenopausal osteoporosis still unknown. This study aimed to determine the role of serum miR-21 expression, concentration of RANKL, OPG, TGF-β1, sclerostin and serum calcium, RANKL/OPG ratio, and physical activity on bone mineral density of spine in hypoestrogenic postmenopausal women with osteoporosis (PMOP) compared with no osteoporosis (PMNOP), with point of interest on the expression of serum miR-21. Methods: this study was conducted by comparative cross-sectional design. The subjects were divided into 2 groups of PMOP and PMNOP. We used an absolute quantification real-time PCR method to determine serum miR-21 expressions level. Results: Median of serum miR-21 expression at the PMOP group was significantly higher compared to PMNOP group (p = 0,001). Serum miR-21 expression, RANKL, RANKL/OPG ratio, and physical activity were significantly correlated with BMD values in the PMOP group. Moderate physical activity was significantly negatively correlated with serum miR-21 expression. We also obtained a linear regression equation BMD = 1,373-0,085*Ln.miR-21-0,176*Log10.RANKL (R2 = 52,5%). Conclusion: serum miR-21 expression in PMOP was higher compared with PMNOP. Serum miR-21 expression proved to have a negative effect on spinal BMD values in hypoestrogenic postmenopausal women with osteoporosis of 8,5%. Obtained equation of BMD = 1,373-0,085*Ln.miR-21-0,176*Log10.RANKL can explain the value of spinal BMD by 52,5%.