53 research outputs found

    Geokimia Batubara Untuk Beberapa Industri

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    Dewasa ini perkembangan batubara sebagai sumber energi alternatif mampu bersaing dengan sumber daya utama yaitu minyak dan gas bumi. Banyak kerugian dan kerusakan yang terjadi akibat tidak diketahuinya karakteristik batubara. Batubara yang tidak memenuhi persyaratan dapat menghasilkan produktivitas yang rendah. Agar produktifitas industri yang memakai batubara tetap terjaga efesiensi dan efektifitasnya maka karakteristik geokimia batubara dari suatu daerah penambangan harus diketahui terlebih dahulu.Untuk mengetahui karakteristik geokimia dilakukan dengan cara analisa proksimat yaitu menentukan kandungan air, kandungan zat terbang, kandungan abu dan kandungan karbon tetap, dan analisa ultimat untuk menentukan kandungan karbon, kandungan sulfur, kandungan hidrogen dan kandungan oksigen. Selain kedua analisa tersebut juga terdapat sifat-sifat penting batubara untuk industri yaitu coal size High Heating Value (HHV), Hardgrove Grindability Index (HGI), ash funshion characteristic, nilai kalor (calorific value) serta sifat caking dan coking.Karakteristik geokimia batubara dalam bidang industri terutama Untuk PLTU diperlukan spesifikasi batubara dengan rata-rata adalah HHV 5242 kcl/kg, moisture 23 %, volatile matter 30,3 %, kandungan abu 7,8 %, kandungan sulfur 0,4 %, dan HGI-nya adalah 61,8. Indusri semen adalah nilai kalor cukup tinggi > 6000 cl/gr, volatile matter medium maksimum 36-42 %, moisture maksimum 12 %, kadar abu maksimum 6 %, kadar sulfur maksimum 0,8 %, kadar alkali dalam abu maksimum 2 % dan variasi kualitas tidak lebih dari 10 % . Untuk industri pengolahan logam, persyaratan batubaranya adalah nilai kalori tinggi > 6000 cl/gr, kandungan C dan H dominan, volatile matter harus mengandung CO / C, kandungan abu maksimal 6 %, sulfur kurang dari 0,0025 %, moisture dan fosfor rendah

    Hubungan Ketinggian dan Diameter Lubang Udara Tungku Pembakaran Biomassa dan Efisiensi Tungku

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    Energi alternatif, misalnya biomassa, dapat dimanfaatkan dengan menggunakan proses pembakaran di dalam tungku. Kendati demikian, tungku tradisional yang tersedia di pasaran atau yang sudah dimanfaatkan masyarakat selama bertahun-tahun efisiensinya masih rendah. Variabel-variabel yang dapat mempengaruhi efisiensi adalah jarak antara ruang bakar dengan lubang masuk udara dan diameter lubang udara. Oleh karena itu, penelitian ini meneliti pengaruh jarak lubang udara dan dan diameter lubang udara terhadap efisiensi tungku. Pengujian dilakukan menggunakan jarak antara ruang bakar dengan lubang udara 30 cm, 40 cm dan 50 cm dan diameter lubang udara 5 cm dan 10 cm. Diameter ruang bakar adalah 13 cm dan diameter bagian atas dari tungku 19 cm. Bahan bakar yang digunakan adalah tempurung kelapa dengan ukuran bervariasi antara 2 cm sampai dengan 4 cm. Pengujian dilakukan dengan memanaskan air dalam panci berdiameter 22 cm dari suhu lingkungan sampai mendidih (100°C). Parameter yang diteliti adalah kinerja tungku yang terdiri dari lama waktu mendidih, FCR, input daya, output daya, kehilangan daya dan efisiensi. Hasilnya menunjukkan bahwa waktu pendinginan tercepat adalah 337 detik dan FCR tertinggi adalah 1,61 kg /jam yaitu yang dihasilkan dengan tungku dengan diameter lubang 10 cm dan jarak lubang udara dari ruang bakar 50 cm. Efisiensi tertinggi 13,92% dicapai oleh tungku dengan jarak lubang udara 30 cm dan diameter lubang udara 5 cm

    Cellular profile of the peritumoral inflammatory infiltrate in squamous cells carcinoma of oral mucosa: Correlation with the expression of Ki67 and histologic grading

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    <p>Abstract</p> <p>Background</p> <p>Squamous cells carcinoma is the most important malignant tumor with primary site in the oral cavity and, given the great exposure of mucosa and lips to the etiologic factors of this neoplasm, its incidence is high. Investigation of the prognostic determinants is significant for the expectations of treatment proposal and cure of the patient. The local immune response represented by peritumoral inflammatory infiltrate is a possible prognostic factor.</p> <p>Methods</p> <p>In this study, oral mucosa samples of squamous cells carcinoma were analyzed, separated according to their histological classification as well as the phenotypical profile of the cells comprising the peritumoral inflammatory infiltrate was investigated by immunohistochemical method, in addiction, the cell proliferation index via protein Ki67 expression was determinated.</p> <p>Results</p> <p>The T lymphocytes made up most of this inflammatory infiltrate, and among these cells, there was a predominance of T CD8 lymphocytes relative to the T CD4 lymphocytes. The B lymhocytes were the second most visualized leucocyte cell type followed by macrophages and neutrophils. The immunohistochemical assessment of Ki-67 positive cells revealed a greater expression of this protein in samples of undifferentiated squamous cells carcinoma.</p> <p>Conclusion</p> <p>The results suggest that the cellular immune response is the main defense mechanism in squamous cells carcinoma of oral mucosa, expressed by the large number of T lymphocytes and macrophages, and that the greatest intensity of local response may be associated with the best prognosis.</p

    Concomitant Targeting of EGF Receptor, TGF-beta and Src Points to a Novel Therapeutic Approach in Pancreatic Cancer

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    To test the hypothesis that concomitant targeting of the epidermal growth factor receptor (EGFR) and transforming growth factor-beta (TGF-β) may offer a novel therapeutic approach in pancreatic cancer, EGFR silencing by RNA interference (shEGFR) was combined with TGF-β sequestration by soluble TGF-β receptor II (sTβRII). Effects on colony formation in 3-dimensional culture, tumor formation in nude mice, and downstream signaling were monitored. In both ASPC-1 and T3M4 cells, either shEGFR or sTβRII significantly inhibited colony formation. However, in ASPC-1 cells, combining shEGFR with sTβRII reduced colony formation more efficiently than either approach alone, whereas in T3M4 cells, shEGFR-mediated inhibition of colony formation was reversed by sTβRII. Similarly, in vivo growth of ASPC-1-derived tumors was attenuated by either shEGFR or sTβRII, and was markedly suppressed by both vectors. By contrast, T3M4-derived tumors either failed to form or were very small when EGFR alone was silenced, and these effects were reversed by sTβRII due to increased cancer cell proliferation. The combination of shEGFR and sTβRII decreased phospho-HER2, phospho-HER3, phoshpo-ERK and phospho-src (Tyr416) levels in ASPC-1 cells but increased their levels in T3M4 cells. Moreover, inhibition of both EGFR and HER2 by lapatinib or of src by SSKI-606, PP2, or dasatinib, blocked the sTβRII-mediated antagonism of colony formation in T3M4 cells. Together, these observations suggest that concomitantly targeting EGFR, TGF-β, and src may constitute a novel therapeutic approach in PDAC that prevents deleterious cross-talk between EGFR family members and TGF-β-dependent pathways

    Long-Term Gemcitabine Treatment Reshapes the Pancreatic Tumor Microenvironment and Sensitizes Murine Carcinoma to Combination Immunotherapy

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    Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death with a median survival time of 6–12 months. Most patients present with disseminated disease and the majority are offered palliative chemotherapy. With no approved treatment modalities for patients who progress on chemotherapy, we explored the effects of long-term Gemcitabine on the tumor microenvironment in order to identify potential therapeutic options for chemo-refractory PDAC. Using a combination of mouse models, primary cell line-derived xenografts, and established tumor cell lines, we first evaluated chemotherapy-induced alterations in the tumor secretome and immune surface proteins by high throughput proteomic arrays. In addition to enhancing antigen presentation and immune checkpoint expression, Gemcitabine consistently increased the synthesis of CCL/CXCL chemokines and TGFβ-associated signals. These secreted factors altered the composition of the tumor stroma, conferring Gemcitabine resistance to cancer-associated fibroblasts in vitro and further enhancing TGFβ1 biosynthesis. Combined Gemcitabine and anti-PD-1 treatment in transgenic models of murine PDAC failed to alter disease course unless mice also underwent genetic or pharmacologic ablation of TGFβ signaling. In the setting of TGFβ signaling deficiency, Gemcitabine and anti-PD-1 led to a robust CD8+ T-cell response and decrease in tumor burden, markedly enhancing overall survival. These results suggest that Gemcitabine successfully primes PDAC tumors for immune checkpoint inhibition by enhancing antigen presentation only following disruption of the immunosuppressive cytokine barrier. Given the current lack of third-line treatment options, this approach warrants consideration in the clinical management of Gemcitabine-refractory PDAC

    Ets-1 Is Essential for Connective Tissue Growth Factor (CTGF/CCN2) Induction by TGF-β1 in Osteoblasts

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    Ets-1 controls osteoblast differentiation and bone development; however, its downstream mechanism of action in osteoblasts remains largely undetermined. CCN2 acts as an anabolic growth factor to regulate osteoblast differentiation and function. CCN2 is induced by TGF-β1 and acts as a mediator of TGF-β1 induced matrix production in osteoblasts; however, the molecular mechanisms that control CCN2 induction are poorly understood. In this study, we investigated the role of Ets-1 for CCN2 induction by TGF-β1 in primary osteoblasts.We demonstrated that Ets-1 is expressed and induced by TGF-β1 treatment in osteoblasts, and that Ets-1 over-expression induces CCN2 protein expression and promoter activity at a level similar to TGF-β1 treatment alone. Additionally, we found that simultaneous Ets-1 over-expression and TGF-β1 treatment synergize to enhance CCN2 induction, and that CCN2 induction by TGF-β1 treatment was impaired using Ets-1 siRNA, demonstrating the requirement of Ets-1 for CCN2 induction by TGF-β1. Site-directed mutagenesis of eight putative Ets-1 motifs (EBE) in the CCN2 promoter demonstrated that specific EBE sites are required for CCN2 induction, and that mutation of EBE sites in closer proximity to TRE or SBE (two sites previously shown to regulate CCN2 induction by TGF-β1) had a greater effect on CCN2 induction, suggesting potential synergetic interaction among these sites for CCN2 induction. In addition, mutation of EBE sites prevented protein complex binding, and this protein complex formation was also inhibited by addition of Ets-1 antibody or Smad 3 antibody, demonstrating that protein binding to EBE motifs as a result of TGF-β1 treatment require synergy between Ets-1 and Smad 3.This study demonstrates that Ets-1 is an essential downstream signaling component for CCN2 induction by TGF-β1 in osteoblasts, and that specific EBE sites in the CCN2 promoter are required for CCN2 promoter transactivation in osteoblasts

    Retinoid Signaling in Pancreatic Cancer, Injury and Regeneration

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    Background: Activation of embryonic signaling pathways quiescent in the adult pancreas is a feature of pancreatic cancer (PC). These discoveries have led to the development of novel inhibitors of pathways such as Notch and Hedgehog signaling that are currently in early phase clinical trials in the treatment of several cancer types. Retinoid signaling is also essential for pancreatic development, and retinoid therapy is used successfully in other malignancies such as leukemia, but little is known concerning retinoid signaling in PC. Methodology/Principal Findings: We investigated the role of retinoid signaling in vitro and in vivo in normal pancreas, pancreatic injury, regeneration and cancer. Retinoid signaling is active in occasional cells in the adult pancreas but is markedly augmented throughout the parenchyma during injury and regeneration. Both chemically induced and genetically engineered mouse models of PC exhibit a lack of retinoid signaling activity compared to normal pancreas. As a consequence, we investigated Cellular Retinoid Binding Protein 1 (CRBP1), a key regulator of retinoid signaling known to play a role in breast cancer development, as a potential therapeutic target. Loss, or significant downregulation of CRBP1 was present in 70% of human PC, and was evident in the very earliest precursor lesions (PanIN-1A). However, in vitro gain and loss of function studies and CRBP1 knockout mice suggested that loss of CRBP1 expression alone was not sufficient to induce carcinogenesis or to alter PC sensitivity to retinoid based therapies. Conclusions/Significance: In conclusion, retinoid signalling appears to play a role in pancreatic regeneration and carcinogenesis, but unlike breast cancer, it is not mediated directly by CRBP1

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700
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