Judul: Potensi Kebakaran Hutan Berdasarkan Ideks Kekeringan, Bahan Bakar dan Praktek Pembakaran oleh Masyarakat
Abstrak: Kebakaran hutan di Indonesia terjadi hampir setiap tahun. Sejumlah kebakaran besar terjadi pada tahun 1982/83, 1987, 199 t , 1993, 1994 dan 1997 yang banyak menimbulkan kerugian. Kebakaran yang terjadi di Sumatera dan Kalimantan pada tahun 1994 dan 1997 telah menyebabkan kerusakan lingkungan di kawasan yang terbakar dan kabut asap yang menyertainya telah mencemari udara di kawasan Asia Tenggara, terutama Malaysia dan Singapura.
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Judul: Model Spasial Tingkat Kerawanan Kebakaran Hutan Dan Lahan Studi Kasus Di Wilayah Propinsi Kalimantan Tengah
Abstrak: Kebakaran hutan merupakan salah satu penyebab utama deforestasi di berbagai negara. Kebakaran hutan menyebabkan kerusakan yang signifikan terhadap lingkungan, hilangnya keanekaragaman hayati dari hutan, polusi udara dan kerugian ekonomi lainnya. Kebakaran yang merusakkan area cukup luas terjadi pada tahun 1991 yang mencapai 118.831 ha, tahun 1994 seluas 161.798 ha, dan yang lebih luas lagi pada tahun 1997‐1998 mencapai 519.752 ha (Suratmo et al. 2003). Kebakaran hutan dan lahan memberikan dampak signifikan terhadap sosial ekonomi, dimana diperkirakan kerugian yang ditimbulkan kebakaran tahun 1997‐1998 berkisar US$ 8.7 juta sampai US$ 9.6 juta. Penelitian ini bertujuan untuk mendapatkan faktor‐faktor yang menjadi faktor utama pendukung terjadinya kebakaran hutan dan lahan, serta menganalisis data curah hujan dan tingkat kerawanan kebakaran hutan dan lahan; dan mendapatkan tingkat kerusakan tegakan di area bekas kebakaran hutan dan lahan. Penelitian ini dilaksanakan di wilayah Kalimantan Tengah yang merupakan daerah dengan hotspot lebih banyak dibandingkan dengan wilayah lain di Indonesia.
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Judul: IPB (Bogor Agricultural University)
Abstrak: The use of Percoll gradients for Leydig cells isolation has been reported to influence cell toxicity and reduce the viability and the amount of living cells after culture. To dissolve this problem, study has been carried out used non toxic Nycodenz gradient to isolated and purified the Leydig cells. The use of Nycodenz gradient for the isolation and purification of Leydig cells has not been done by other researchers. To obtain the optimum condition of Leydig cells production, growth factor is required as supporting factors for development of growing cells. Therefore, hCG and ITS has been used in this study. Leydig cells conditioned medium (LCM) contained bioactive materials such as testosterone and growth factors. The Leydig cells conditioned medium as culture medium for bone marrow mesenchymal stem cells will be used to determine its influence to differentiation of cells. The phase of this study included: 1. Isolation and purification of Leydig cells using Nycodenz gradient : (I) with 3 column ( 5 % , 10 % , 15 % ) and ( II ) with 5 columns ( 4 % , 8 % , 10 % , 12 % , 15 % ) and Percoll gradient ( 21 % , 26 % , 34 % , 40 % , 60 % ) as a control . 2. In vitro culture of the best result from cell purification was cultured with the addition of hormones and growth factors : (1) DMEM+NBCS 10% as control, (2) DMEM + NBCS + 2.5 IU/ml hCG , (3) DMEM + NBCS+ 5 ug / ml insulin, 10 ug/ml transferrin, selenium 5 ug/ml (ITS ) and (4) DMEM +NBCS + hCG+ITS . 3 . The concentration of testosteron and protein analyzed from Leydig cells conditioned medium has been used for culturing bone marrow mesenchymal stem cells. The result of first phase study was Nycodenz gradient have the same purity and viability compared with Percoll gradient. After 3 days cultured, in Nycodenz gradient the concentration and viability of Leydig cells more higher than Percoll gradient. The combination of hCG and ITS in DMEM produced Leydig cell proliferation (90.64%) higher compared with hCG (86.99%), ITS (88.35%) and control (86.82%). Proliferation rate (population doubling time, PDT) from primary culture using combination of hCG and ITS showed the fastest (0.88 day) compared with ITS (0.97 day), hCG (1.02 day) and control (1.03 day). The same result of Leydig cells proliferation rate has also showed in first and second cell lines. Testosterone consentration analyzed was the highest (5.25 ng/ml) in DMEM combination with hCG and ITS compared with other treatments (hCG 5.06 ng/ml; ITS 3.19 ng/ml and control 2.46 ng/ml). Differentiation to became Leydig cells from bone marrow mesenchymal stem cells has been known from positive reaction to 3β-HSD staining. Added of hCG to Leydig cells conditioned medium was able to increased the number of Leydig cells to 71.9%. It was also showed that concentration of testosterone has been increased (0.93 ng/ml and 10.22 ng/ml) in the culture medium. The combination of hCG and ITS in DMEM had testosterone (0.71 ng/ml) and protein
Keyword: Leydig cells, rat, Nycodenz, testosterone, mesenchymal stem cells, bone marrow, conditioned medium, transdiferentiation