ANALISIS KESTABILAN LERENG DI PIT PAJAJARAN PT. TAMBANG TONDANO NUSAJAYA SULAWESI UTARA

PT. Tambang Tondano Nusajaya merupakan perusahaan tambang emas di Kabupaten Minahasa Utara dan Kotamadya Bitung, Provinsi Sulawesi Utara. Kegiatan penambangan dilakukan dengan membuat lereng berjenjang. Pembuatan lereng di perusahaan tersebut tidak didasarkan pada kajian geoteknik, sehingga geometri lereng dibuat sama setiap pit tanpa memperhatikan perbedaan karakteristik massa batuan. Perlakuan yang sama terhadap geometri lereng dengan mengabaikan karakteristik massa batuan pembentuknya mempunyai tingkat keyakinan terhadap kestabilan lereng yang rendah.Penelitian dilakukan untuk mengklasifikasikan massa batuan dengan sistem rock mass rating (RMR) dan geological strenght index (GSI). Penelitian ini dilakukan pada dua domain batuan, yaitu massa batuan andesit di lereng barat (SLP 1) dan massa batuan andesit di lereng timur (SLP 2).Nilai RMR yang didapatkan dari pembobotan lima parameter RMR pada masing-masing lokasi adalah SLP 1 = 55 dan SLP 2 = 73. Nilai GSI merupakan RMR-5 (Hoek and Brown, 2002), sehingga didapatkan nilai GSI pada masing-masing lokasi penelitan adalah SLP 1= 50 dan SLP 2 = 68. Untuk mendapatkan nilai kohesi (c) dan sudut gesek dalam (ϕ) pada massa batuan di lokasi penelitian digunakan pendekatan kriteria keruntuhan Hoek & Brown (2002). Nilai kohesi (c) dan sudut gesek dalam (ϕ) secara berurutan pada masing lokasi penelitian adalah SLP 1 = 98 KPa, 51o dan SLP 2 = 406 KPa, 62o.Dari hasil analisis dapat disimpulkan bahwa lereng desain dengan tinggi 15 m dan kemiringan lereng 60o dalam keadaan stabil baik di SLP 1 maupun SLP 2. Kemiringan dapat dioptimumkan sampai 70o. Lereng aktual SLP 1 dengan tinggi 15 m dan kemiringan lereng 66o dalam keadaan stabil. Begitu pula lereng aktual SLP 2 dengan tinggi 15 m dan kemiringan lereng 69o juga dalam keadaan stabil. Lebar lereng yang diterapkan yaitu sebesar 5 m tidak memenuhi untuk menangkap batu jatuh. Untuk lereng dengan tinggi 15 m dan kemiringan lereng 60o lebar minimum 5,4 m dan untuk lereng dengan tinggi 15 m dan kemiringan lereng 70o lebar minimum sebesar 5,6 m. Lereng keseluruhan di SLP 1 dan SLP 2 dalam keadaan stabil. Kegiatan untuk menunjang kestabilan lereng pada daerah penelitian adalah dengan pemantauan lereng, seperti pemasangan crack meter dan scaling.Kata Kunci: RMR, GSI, SLP 1, SLP 2, Geometri Lereng

Prognostic value of LINE-1 retrotransposon expression and its subcellular localization in breast cancer

Long interspersed nuclear element 1 (L1) belongs to a family of retrotransposons. Expression of the normally repressed L1 retrotransposons has been shown to induce genome instability by creating DNA double-stranded breaks and chromosomal rearrangements through the process of retrotransposition. At present, little is known about the expression of L1-encoded ORF1p and ORF2p which are indispensable for its retrotransposition activity. Given its potentially harmful effects on the genome, we investigated the implications of both ORF1p and ORF2p expression and their subcellular localization in a range of breast cancer cell lines and breast tumor tissues including 15 normal breast tissues, 25 fibroadenomas, 25 ductal carcinomas in situ (DCIS), and 95 invasive cancers. Clinicopathologic parameters and survival outcomes were investigated in association with the cytoplasmic and nuclear expression of ORF1p and ORF2p using univariate and multivariate analysis. High cytoplasmic expression of ORF1p and ORF2p was seen in DCIS tumors, but they were not related with survival outcome. The majority of invasive cancers were found to express both ORF1p and ORF2p in the cytoplasm, while nuclear expression was also seen in a subclass of those invasive cancers in the range of 28-31 %. Tumors with high nuclear expression of ORF1p and ORF2p were more significantly associated with lymph node metastasis (p = 0.001) and the worst patient survival (p < 0.0001) than those with cytoplasmic expression. This is the first study examining the effects of both ORF1p and ORF2p expression in breast cancer tissues. Our observation shows altered expression patterns of ORF1p and ORF2p within invasive cancers, which are related to differences in overall patient survival. The differing patterns of both cytoplasmic and nuclear ORF1p and ORF2p expression indicate that further studies of the biology and function of L1 retrotransposons are required in breast cancer

Islet inflammation, hemosiderosis, and fibrosis in intrauterine growth-restricted and high fat-fed sprague-dawley rats

Prenatal and postnatal factors such as intrauterine growth restriction (IUGR) and high-fat (HF) diet contribute to type 2 diabetes. Our aim was to determine whether IUGR and HF diets interact in type 2 diabetes pathogenesis, with particular attention focused on pancreatic islet morphology including assessment for inflammation. A surgical model of IUGR (bilateral uterine artery ligation) in Sprague-Dawley rats with sham controls was used. Pups were fed either HF or chow diets after weaning. Serial measures of body weight and glucose tolerance were performed. At 25 weeks of age, rat pancreases were harvested for histologic assessment. The birth weight of IUGR pups was 13% lower than that of sham pups. HF diet caused excess weight gain, dyslipidemia, hyperinsulinemia, and mild glucose intolerance, however, this was not aggravated further by IUGR. Markedly abnormal islet morphology was evident in 0 of 6 sham-chow, 5 of 8 sham-HF, 4 of 8 IUGR-chow, and 8 of 9 IUGR-HF rats (chi-square, P = 0.007). Abnormal islets were characterized by larger size, irregular shape, inflammation with CD68-positive cells, marked fibrosis, and hemosiderosis. β-Cell mass was not altered by IUGR. In conclusion, HF and IUGR independently contribute to islet injury characterized by inflammation, hemosiderosis, and fibrosis. This suggests that both HF and IUGR can induce islet injury via converging pathways. The potential pathogenic or permissive role of iron in this process of islet inflammation warrants further investigation

Altered decidual DC-SIGN + antigen-presenting cells and impaired regulatory T-cell induction in preeclampsia

Regulatory T (Treg) cell expansion is required for tolerance of the semi-allogeneic fetus in healthy pregnancy and impaired in preeclampsia in humans. However, the reasons remain unknown. Herein, we show that expansion of CD4+Helios-Foxp3+ adaptive Treg (iTreg) cells, rather than CD4+Helios+Foxp3+ natural Treg cells, accounts for this expansion in healthy pregnancy. This expansion is even more pronounced in the decidua, where there is an overrepresentation of iTreg cells. In preeclampsia, however, there is impaired systemic iTreg cell expansion, associated with a lack of iTreg cell overrepresentation in the decidua. Because decidual antigen-presenting cells (APCs) may be important for iTreg cell induction, we studied decidual CD14+ APCs using immunohistochemistry and flow cytometry. We show that decidual CD14 +DC-SIGN+ APCs are closely associated with Foxp3 + Treg cells. Furthermore, CD14+DC-SIGN+ cells display a distinct phenotype compared with their CD14+DC-SIGN - counterparts. In particular, they have increased expression of tolerogenic molecules, HLA-G, and immunoglobulin-like transcript 4. In vitro, CD14+DC-SIGN+ APCs from healthy pregnant women induced iTreg cells significantly more efficiently than CD14+DC-SIGN - APCs. Conversely, in preeclampsia, both CD14+DC- SIGN+ and CD14+DC-SIGN- APCs induced iTreg cells poorly. These results suggest that decidual CD14+DC-SIGN + APCs may play important roles in iTreg cell induction, a process that is defective in preeclampsia and likely contributes to its pathogenesis